1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2003, 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 Rtsfind; use Rtsfind;
46 with Sdefault; use Sdefault;
48 with Sem_Cat; use Sem_Cat;
49 with Sem_Ch6; use Sem_Ch6;
50 with Sem_Ch8; use Sem_Ch8;
51 with Sem_Dist; use Sem_Dist;
52 with Sem_Eval; use Sem_Eval;
53 with Sem_Res; use Sem_Res;
54 with Sem_Type; use Sem_Type;
55 with Sem_Util; use Sem_Util;
56 with Stand; use Stand;
57 with Sinfo; use Sinfo;
58 with Sinput; use Sinput;
59 with Snames; use Snames;
61 with Stringt; use Stringt;
62 with Targparm; use Targparm;
63 with Ttypes; use Ttypes;
64 with Ttypef; use Ttypef;
65 with Tbuild; use Tbuild;
66 with Uintp; use Uintp;
67 with Urealp; use Urealp;
68 with Widechar; use Widechar;
70 package body Sem_Attr is
72 True_Value : constant Uint := Uint_1;
73 False_Value : constant Uint := Uint_0;
74 -- Synonyms to be used when these constants are used as Boolean values
76 Bad_Attribute : exception;
77 -- Exception raised if an error is detected during attribute processing,
78 -- used so that we can abandon the processing so we don't run into
79 -- trouble with cascaded errors.
81 -- The following array is the list of attributes defined in the Ada 83 RM
83 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
89 Attribute_Constrained |
102 Attribute_Leading_Part |
104 Attribute_Machine_Emax |
105 Attribute_Machine_Emin |
106 Attribute_Machine_Mantissa |
107 Attribute_Machine_Overflows |
108 Attribute_Machine_Radix |
109 Attribute_Machine_Rounds |
115 Attribute_Safe_Emax |
116 Attribute_Safe_Large |
117 Attribute_Safe_Small |
120 Attribute_Storage_Size |
122 Attribute_Terminated |
125 Attribute_Width => True,
128 -----------------------
129 -- Local_Subprograms --
130 -----------------------
132 procedure Eval_Attribute (N : Node_Id);
133 -- Performs compile time evaluation of attributes where possible, leaving
134 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
135 -- set, and replacing the node with a literal node if the value can be
136 -- computed at compile time. All static attribute references are folded,
137 -- as well as a number of cases of non-static attributes that can always
138 -- be computed at compile time (e.g. floating-point model attributes that
139 -- are applied to non-static subtypes). Of course in such cases, the
140 -- Is_Static_Expression flag will not be set on the resulting literal.
141 -- Note that the only required action of this procedure is to catch the
142 -- static expression cases as described in the RM. Folding of other cases
143 -- is done where convenient, but some additional non-static folding is in
144 -- N_Expand_Attribute_Reference in cases where this is more convenient.
146 function Is_Anonymous_Tagged_Base
150 -- For derived tagged types that constrain parent discriminants we build
151 -- an anonymous unconstrained base type. We need to recognize the relation
152 -- between the two when analyzing an access attribute for a constrained
153 -- component, before the full declaration for Typ has been analyzed, and
154 -- where therefore the prefix of the attribute does not match the enclosing
157 -----------------------
158 -- Analyze_Attribute --
159 -----------------------
161 procedure Analyze_Attribute (N : Node_Id) is
162 Loc : constant Source_Ptr := Sloc (N);
163 Aname : constant Name_Id := Attribute_Name (N);
164 P : constant Node_Id := Prefix (N);
165 Exprs : constant List_Id := Expressions (N);
166 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
171 -- Type of prefix after analysis
173 P_Base_Type : Entity_Id;
174 -- Base type of prefix after analysis
176 -----------------------
177 -- Local Subprograms --
178 -----------------------
180 procedure Analyze_Access_Attribute;
181 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
182 -- Internally, Id distinguishes which of the three cases is involved.
184 procedure Check_Array_Or_Scalar_Type;
185 -- Common procedure used by First, Last, Range attribute to check
186 -- that the prefix is a constrained array or scalar type, or a name
187 -- of an array object, and that an argument appears only if appropriate
188 -- (i.e. only in the array case).
190 procedure Check_Array_Type;
191 -- Common semantic checks for all array attributes. Checks that the
192 -- prefix is a constrained array type or the name of an array object.
193 -- The error message for non-arrays is specialized appropriately.
195 procedure Check_Asm_Attribute;
196 -- Common semantic checks for Asm_Input and Asm_Output attributes
198 procedure Check_Component;
199 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
200 -- Position. Checks prefix is an appropriate selected component.
202 procedure Check_Decimal_Fixed_Point_Type;
203 -- Check that prefix of attribute N is a decimal fixed-point type
205 procedure Check_Dereference;
206 -- If the prefix of attribute is an object of an access type, then
207 -- introduce an explicit deference, and adjust P_Type accordingly.
209 procedure Check_Discrete_Type;
210 -- Verify that prefix of attribute N is a discrete type
213 -- Check that no attribute arguments are present
215 procedure Check_Either_E0_Or_E1;
216 -- Check that there are zero or one attribute arguments present
219 -- Check that exactly one attribute argument is present
222 -- Check that two attribute arguments are present
224 procedure Check_Enum_Image;
225 -- If the prefix type is an enumeration type, set all its literals
226 -- as referenced, since the image function could possibly end up
227 -- referencing any of the literals indirectly.
229 procedure Check_Fixed_Point_Type;
230 -- Verify that prefix of attribute N is a fixed type
232 procedure Check_Fixed_Point_Type_0;
233 -- Verify that prefix of attribute N is a fixed type and that
234 -- no attribute expressions are present
236 procedure Check_Floating_Point_Type;
237 -- Verify that prefix of attribute N is a float type
239 procedure Check_Floating_Point_Type_0;
240 -- Verify that prefix of attribute N is a float type and that
241 -- no attribute expressions are present
243 procedure Check_Floating_Point_Type_1;
244 -- Verify that prefix of attribute N is a float type and that
245 -- exactly one attribute expression is present
247 procedure Check_Floating_Point_Type_2;
248 -- Verify that prefix of attribute N is a float type and that
249 -- two attribute expressions are present
251 procedure Legal_Formal_Attribute;
252 -- Common processing for attributes Definite, and Has_Discriminants
254 procedure Check_Integer_Type;
255 -- Verify that prefix of attribute N is an integer type
257 procedure Check_Library_Unit;
258 -- Verify that prefix of attribute N is a library unit
260 procedure Check_Not_Incomplete_Type;
261 -- Check that P (the prefix of the attribute) is not an incomplete
262 -- type or a private type for which no full view has been given.
264 procedure Check_Object_Reference (P : Node_Id);
265 -- Check that P (the prefix of the attribute) is an object reference
267 procedure Check_Program_Unit;
268 -- Verify that prefix of attribute N is a program unit
270 procedure Check_Real_Type;
271 -- Verify that prefix of attribute N is fixed or float type
273 procedure Check_Scalar_Type;
274 -- Verify that prefix of attribute N is a scalar type
276 procedure Check_Standard_Prefix;
277 -- Verify that prefix of attribute N is package Standard
279 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
280 -- Validity checking for stream attribute. Nam is the TSS name of the
281 -- corresponding possible defined attribute function (e.g. for the
282 -- Read attribute, Nam will be TSS_Stream_Read).
284 procedure Check_Task_Prefix;
285 -- Verify that prefix of attribute N is a task or task type
287 procedure Check_Type;
288 -- Verify that the prefix of attribute N is a type
290 procedure Check_Unit_Name (Nod : Node_Id);
291 -- Check that Nod is of the form of a library unit name, i.e that
292 -- it is an identifier, or a selected component whose prefix is
293 -- itself of the form of a library unit name. Note that this is
294 -- quite different from Check_Program_Unit, since it only checks
295 -- the syntactic form of the name, not the semantic identity. This
296 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
297 -- UET_Address) which can refer to non-visible unit.
299 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
300 pragma No_Return (Error_Attr);
301 procedure Error_Attr;
302 pragma No_Return (Error_Attr);
303 -- Posts error using Error_Msg_N at given node, sets type of attribute
304 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
305 -- semantic processing. The message typically contains a % insertion
306 -- character which is replaced by the attribute name. The call with
307 -- no arguments is used when the caller has already generated the
308 -- required error messages.
310 procedure Standard_Attribute (Val : Int);
311 -- Used to process attributes whose prefix is package Standard which
312 -- yield values of type Universal_Integer. The attribute reference
313 -- node is rewritten with an integer literal of the given value.
315 procedure Unexpected_Argument (En : Node_Id);
316 -- Signal unexpected attribute argument (En is the argument)
318 procedure Validate_Non_Static_Attribute_Function_Call;
319 -- Called when processing an attribute that is a function call to a
320 -- non-static function, i.e. an attribute function that either takes
321 -- non-scalar arguments or returns a non-scalar result. Verifies that
322 -- such a call does not appear in a preelaborable context.
324 ------------------------------
325 -- Analyze_Access_Attribute --
326 ------------------------------
328 procedure Analyze_Access_Attribute is
329 Acc_Type : Entity_Id;
334 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
335 -- Build an access-to-object type whose designated type is DT,
336 -- and whose Ekind is appropriate to the attribute type. The
337 -- type that is constructed is returned as the result.
339 procedure Build_Access_Subprogram_Type (P : Node_Id);
340 -- Build an access to subprogram whose designated type is
341 -- the type of the prefix. If prefix is overloaded, so it the
342 -- node itself. The result is stored in Acc_Type.
344 ------------------------------
345 -- Build_Access_Object_Type --
346 ------------------------------
348 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
352 if Aname = Name_Unrestricted_Access then
355 (E_Allocator_Type, Current_Scope, Loc, 'A');
359 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
362 Set_Etype (Typ, Typ);
363 Init_Size_Align (Typ);
365 Set_Associated_Node_For_Itype (Typ, N);
366 Set_Directly_Designated_Type (Typ, DT);
368 end Build_Access_Object_Type;
370 ----------------------------------
371 -- Build_Access_Subprogram_Type --
372 ----------------------------------
374 procedure Build_Access_Subprogram_Type (P : Node_Id) is
375 Index : Interp_Index;
378 function Get_Kind (E : Entity_Id) return Entity_Kind;
379 -- Distinguish between access to regular and protected
386 function Get_Kind (E : Entity_Id) return Entity_Kind is
388 if Convention (E) = Convention_Protected then
389 return E_Access_Protected_Subprogram_Type;
391 return E_Access_Subprogram_Type;
395 -- Start of processing for Build_Access_Subprogram_Type
398 -- In the case of an access to subprogram, use the name of the
399 -- subprogram itself as the designated type. Type-checking in
400 -- this case compares the signatures of the designated types.
402 if not Is_Overloaded (P) then
405 (Get_Kind (Entity (P)), Current_Scope, Loc, 'A');
406 Set_Etype (Acc_Type, Acc_Type);
407 Set_Directly_Designated_Type (Acc_Type, Entity (P));
408 Set_Etype (N, Acc_Type);
411 Get_First_Interp (P, Index, It);
412 Set_Etype (N, Any_Type);
414 while Present (It.Nam) loop
415 if not Is_Intrinsic_Subprogram (It.Nam) then
418 (Get_Kind (It.Nam), Current_Scope, Loc, 'A');
419 Set_Etype (Acc_Type, Acc_Type);
420 Set_Directly_Designated_Type (Acc_Type, It.Nam);
421 Add_One_Interp (N, Acc_Type, Acc_Type);
424 Get_Next_Interp (Index, It);
427 if Etype (N) = Any_Type then
428 Error_Attr ("prefix of % attribute cannot be intrinsic", P);
431 end Build_Access_Subprogram_Type;
433 -- Start of processing for Analyze_Access_Attribute
438 if Nkind (P) = N_Character_Literal then
440 ("prefix of % attribute cannot be enumeration literal", P);
443 -- Case of access to subprogram
445 if Is_Entity_Name (P)
446 and then Is_Overloadable (Entity (P))
448 -- Not allowed for nested subprograms if No_Implicit_Dynamic_Code
449 -- restriction set (since in general a trampoline is required).
451 if not Is_Library_Level_Entity (Entity (P)) then
452 Check_Restriction (No_Implicit_Dynamic_Code, P);
455 -- Build the appropriate subprogram type
457 Build_Access_Subprogram_Type (P);
459 -- For unrestricted access, kill current values, since this
460 -- attribute allows a reference to a local subprogram that
461 -- could modify local variables to be passed out of scope
463 if Aname = Name_Unrestricted_Access then
469 -- Component is an operation of a protected type
471 elsif Nkind (P) = N_Selected_Component
472 and then Is_Overloadable (Entity (Selector_Name (P)))
474 if Ekind (Entity (Selector_Name (P))) = E_Entry then
475 Error_Attr ("prefix of % attribute must be subprogram", P);
478 Build_Access_Subprogram_Type (Selector_Name (P));
482 -- Deal with incorrect reference to a type, but note that some
483 -- accesses are allowed (references to the current type instance).
485 if Is_Entity_Name (P) then
486 Scop := Current_Scope;
489 if Is_Type (Typ) then
491 -- OK if we are within the scope of a limited type
492 -- let's mark the component as having per object constraint
494 if Is_Anonymous_Tagged_Base (Scop, Typ) then
502 Q : Node_Id := Parent (N);
506 and then Nkind (Q) /= N_Component_Declaration
511 Set_Has_Per_Object_Constraint (
512 Defining_Identifier (Q), True);
516 if Nkind (P) = N_Expanded_Name then
518 ("current instance prefix must be a direct name", P);
521 -- If a current instance attribute appears within a
522 -- a component constraint it must appear alone; other
523 -- contexts (default expressions, within a task body)
524 -- are not subject to this restriction.
526 if not In_Default_Expression
527 and then not Has_Completion (Scop)
529 Nkind (Parent (N)) /= N_Discriminant_Association
531 Nkind (Parent (N)) /= N_Index_Or_Discriminant_Constraint
534 ("current instance attribute must appear alone", N);
537 -- OK if we are in initialization procedure for the type
538 -- in question, in which case the reference to the type
539 -- is rewritten as a reference to the current object.
541 elsif Ekind (Scop) = E_Procedure
542 and then Is_Init_Proc (Scop)
543 and then Etype (First_Formal (Scop)) = Typ
546 Make_Attribute_Reference (Loc,
547 Prefix => Make_Identifier (Loc, Name_uInit),
548 Attribute_Name => Name_Unrestricted_Access));
552 -- OK if a task type, this test needs sharpening up ???
554 elsif Is_Task_Type (Typ) then
557 -- Otherwise we have an error case
560 Error_Attr ("% attribute cannot be applied to type", P);
566 -- If we fall through, we have a normal access to object case.
567 -- Unrestricted_Access is legal wherever an allocator would be
568 -- legal, so its Etype is set to E_Allocator. The expected type
569 -- of the other attributes is a general access type, and therefore
570 -- we label them with E_Access_Attribute_Type.
572 if not Is_Overloaded (P) then
573 Acc_Type := Build_Access_Object_Type (P_Type);
574 Set_Etype (N, Acc_Type);
577 Index : Interp_Index;
581 Set_Etype (N, Any_Type);
582 Get_First_Interp (P, Index, It);
584 while Present (It.Typ) loop
585 Acc_Type := Build_Access_Object_Type (It.Typ);
586 Add_One_Interp (N, Acc_Type, Acc_Type);
587 Get_Next_Interp (Index, It);
592 -- If we have an access to an object, and the attribute comes
593 -- from source, then set the object as potentially source modified.
594 -- We do this because the resulting access pointer can be used to
595 -- modify the variable, and we might not detect this, leading to
596 -- some junk warnings.
598 if Is_Entity_Name (P) then
599 Set_Never_Set_In_Source (Entity (P), False);
602 -- Check for aliased view unless unrestricted case. We allow
603 -- a nonaliased prefix when within an instance because the
604 -- prefix may have been a tagged formal object, which is
605 -- defined to be aliased even when the actual might not be
606 -- (other instance cases will have been caught in the generic).
608 if Aname /= Name_Unrestricted_Access
609 and then not Is_Aliased_View (P)
610 and then not In_Instance
612 Error_Attr ("prefix of % attribute must be aliased", P);
614 end Analyze_Access_Attribute;
616 --------------------------------
617 -- Check_Array_Or_Scalar_Type --
618 --------------------------------
620 procedure Check_Array_Or_Scalar_Type is
624 -- Dimension number for array attributes.
627 -- Case of string literal or string literal subtype. These cases
628 -- cannot arise from legal Ada code, but the expander is allowed
629 -- to generate them. They require special handling because string
630 -- literal subtypes do not have standard bounds (the whole idea
631 -- of these subtypes is to avoid having to generate the bounds)
633 if Ekind (P_Type) = E_String_Literal_Subtype then
634 Set_Etype (N, Etype (First_Index (P_Base_Type)));
639 elsif Is_Scalar_Type (P_Type) then
643 Error_Attr ("invalid argument in % attribute", E1);
645 Set_Etype (N, P_Base_Type);
649 -- The following is a special test to allow 'First to apply to
650 -- private scalar types if the attribute comes from generated
651 -- code. This occurs in the case of Normalize_Scalars code.
653 elsif Is_Private_Type (P_Type)
654 and then Present (Full_View (P_Type))
655 and then Is_Scalar_Type (Full_View (P_Type))
656 and then not Comes_From_Source (N)
658 Set_Etype (N, Implementation_Base_Type (P_Type));
660 -- Array types other than string literal subtypes handled above
665 -- We know prefix is an array type, or the name of an array
666 -- object, and that the expression, if present, is static
667 -- and within the range of the dimensions of the type.
669 if Is_Array_Type (P_Type) then
670 Index := First_Index (P_Base_Type);
672 else pragma Assert (Is_Access_Type (P_Type));
673 Index := First_Index (Base_Type (Designated_Type (P_Type)));
678 -- First dimension assumed
680 Set_Etype (N, Base_Type (Etype (Index)));
683 D := UI_To_Int (Intval (E1));
685 for J in 1 .. D - 1 loop
689 Set_Etype (N, Base_Type (Etype (Index)));
690 Set_Etype (E1, Standard_Integer);
693 end Check_Array_Or_Scalar_Type;
695 ----------------------
696 -- Check_Array_Type --
697 ----------------------
699 procedure Check_Array_Type is
701 -- Dimension number for array attributes.
704 -- If the type is a string literal type, then this must be generated
705 -- internally, and no further check is required on its legality.
707 if Ekind (P_Type) = E_String_Literal_Subtype then
710 -- If the type is a composite, it is an illegal aggregate, no point
713 elsif P_Type = Any_Composite then
717 -- Normal case of array type or subtype
719 Check_Either_E0_Or_E1;
721 if Is_Array_Type (P_Type) then
722 if not Is_Constrained (P_Type)
723 and then Is_Entity_Name (P)
724 and then Is_Type (Entity (P))
726 -- Note: we do not call Error_Attr here, since we prefer to
727 -- continue, using the relevant index type of the array,
728 -- even though it is unconstrained. This gives better error
729 -- recovery behavior.
731 Error_Msg_Name_1 := Aname;
733 ("prefix for % attribute must be constrained array", P);
736 D := Number_Dimensions (P_Type);
738 elsif Is_Access_Type (P_Type)
739 and then Is_Array_Type (Designated_Type (P_Type))
741 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
742 Error_Attr ("prefix of % attribute cannot be access type", P);
745 D := Number_Dimensions (Designated_Type (P_Type));
747 -- If there is an implicit dereference, then we must freeze
748 -- the designated type of the access type, since the type of
749 -- the referenced array is this type (see AI95-00106).
751 Freeze_Before (N, Designated_Type (P_Type));
754 if Is_Private_Type (P_Type) then
756 ("prefix for % attribute may not be private type", P);
758 elsif Attr_Id = Attribute_First
760 Attr_Id = Attribute_Last
762 Error_Attr ("invalid prefix for % attribute", P);
765 Error_Attr ("prefix for % attribute must be array", P);
770 Resolve (E1, Any_Integer);
771 Set_Etype (E1, Standard_Integer);
773 if not Is_Static_Expression (E1)
774 or else Raises_Constraint_Error (E1)
777 ("expression for dimension must be static!", E1);
780 elsif UI_To_Int (Expr_Value (E1)) > D
781 or else UI_To_Int (Expr_Value (E1)) < 1
783 Error_Attr ("invalid dimension number for array type", E1);
786 end Check_Array_Type;
788 -------------------------
789 -- Check_Asm_Attribute --
790 -------------------------
792 procedure Check_Asm_Attribute is
797 -- Check first argument is static string expression
799 Analyze_And_Resolve (E1, Standard_String);
801 if Etype (E1) = Any_Type then
804 elsif not Is_OK_Static_Expression (E1) then
806 ("constraint argument must be static string expression!", E1);
810 -- Check second argument is right type
812 Analyze_And_Resolve (E2, Entity (P));
814 -- Note: that is all we need to do, we don't need to check
815 -- that it appears in a correct context. The Ada type system
816 -- will do that for us.
818 end Check_Asm_Attribute;
820 ---------------------
821 -- Check_Component --
822 ---------------------
824 procedure Check_Component is
828 if Nkind (P) /= N_Selected_Component
830 (Ekind (Entity (Selector_Name (P))) /= E_Component
832 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
835 ("prefix for % attribute must be selected component", P);
839 ------------------------------------
840 -- Check_Decimal_Fixed_Point_Type --
841 ------------------------------------
843 procedure Check_Decimal_Fixed_Point_Type is
847 if not Is_Decimal_Fixed_Point_Type (P_Type) then
849 ("prefix of % attribute must be decimal type", P);
851 end Check_Decimal_Fixed_Point_Type;
853 -----------------------
854 -- Check_Dereference --
855 -----------------------
857 procedure Check_Dereference is
859 if Is_Object_Reference (P)
860 and then Is_Access_Type (P_Type)
863 Make_Explicit_Dereference (Sloc (P),
864 Prefix => Relocate_Node (P)));
866 Analyze_And_Resolve (P);
869 if P_Type = Any_Type then
873 P_Base_Type := Base_Type (P_Type);
875 end Check_Dereference;
877 -------------------------
878 -- Check_Discrete_Type --
879 -------------------------
881 procedure Check_Discrete_Type is
885 if not Is_Discrete_Type (P_Type) then
886 Error_Attr ("prefix of % attribute must be discrete type", P);
888 end Check_Discrete_Type;
894 procedure Check_E0 is
897 Unexpected_Argument (E1);
905 procedure Check_E1 is
907 Check_Either_E0_Or_E1;
911 -- Special-case attributes that are functions and that appear as
912 -- the prefix of another attribute. Error is posted on parent.
914 if Nkind (Parent (N)) = N_Attribute_Reference
915 and then (Attribute_Name (Parent (N)) = Name_Address
917 Attribute_Name (Parent (N)) = Name_Code_Address
919 Attribute_Name (Parent (N)) = Name_Access)
921 Error_Msg_Name_1 := Attribute_Name (Parent (N));
922 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
923 Set_Etype (Parent (N), Any_Type);
924 Set_Entity (Parent (N), Any_Type);
928 Error_Attr ("missing argument for % attribute", N);
937 procedure Check_E2 is
940 Error_Attr ("missing arguments for % attribute (2 required)", N);
942 Error_Attr ("missing argument for % attribute (2 required)", N);
946 ---------------------------
947 -- Check_Either_E0_Or_E1 --
948 ---------------------------
950 procedure Check_Either_E0_Or_E1 is
953 Unexpected_Argument (E2);
955 end Check_Either_E0_Or_E1;
957 ----------------------
958 -- Check_Enum_Image --
959 ----------------------
961 procedure Check_Enum_Image is
965 if Is_Enumeration_Type (P_Base_Type) then
966 Lit := First_Literal (P_Base_Type);
967 while Present (Lit) loop
968 Set_Referenced (Lit);
972 end Check_Enum_Image;
974 ----------------------------
975 -- Check_Fixed_Point_Type --
976 ----------------------------
978 procedure Check_Fixed_Point_Type is
982 if not Is_Fixed_Point_Type (P_Type) then
983 Error_Attr ("prefix of % attribute must be fixed point type", P);
985 end Check_Fixed_Point_Type;
987 ------------------------------
988 -- Check_Fixed_Point_Type_0 --
989 ------------------------------
991 procedure Check_Fixed_Point_Type_0 is
993 Check_Fixed_Point_Type;
995 end Check_Fixed_Point_Type_0;
997 -------------------------------
998 -- Check_Floating_Point_Type --
999 -------------------------------
1001 procedure Check_Floating_Point_Type is
1005 if not Is_Floating_Point_Type (P_Type) then
1006 Error_Attr ("prefix of % attribute must be float type", P);
1008 end Check_Floating_Point_Type;
1010 ---------------------------------
1011 -- Check_Floating_Point_Type_0 --
1012 ---------------------------------
1014 procedure Check_Floating_Point_Type_0 is
1016 Check_Floating_Point_Type;
1018 end Check_Floating_Point_Type_0;
1020 ---------------------------------
1021 -- Check_Floating_Point_Type_1 --
1022 ---------------------------------
1024 procedure Check_Floating_Point_Type_1 is
1026 Check_Floating_Point_Type;
1028 end Check_Floating_Point_Type_1;
1030 ---------------------------------
1031 -- Check_Floating_Point_Type_2 --
1032 ---------------------------------
1034 procedure Check_Floating_Point_Type_2 is
1036 Check_Floating_Point_Type;
1038 end Check_Floating_Point_Type_2;
1040 ------------------------
1041 -- Check_Integer_Type --
1042 ------------------------
1044 procedure Check_Integer_Type is
1048 if not Is_Integer_Type (P_Type) then
1049 Error_Attr ("prefix of % attribute must be integer type", P);
1051 end Check_Integer_Type;
1053 ------------------------
1054 -- Check_Library_Unit --
1055 ------------------------
1057 procedure Check_Library_Unit is
1059 if not Is_Compilation_Unit (Entity (P)) then
1060 Error_Attr ("prefix of % attribute must be library unit", P);
1062 end Check_Library_Unit;
1064 -------------------------------
1065 -- Check_Not_Incomplete_Type --
1066 -------------------------------
1068 procedure Check_Not_Incomplete_Type is
1070 if not Is_Entity_Name (P)
1071 or else not Is_Type (Entity (P))
1072 or else In_Default_Expression
1077 Check_Fully_Declared (P_Type, P);
1079 end Check_Not_Incomplete_Type;
1081 ----------------------------
1082 -- Check_Object_Reference --
1083 ----------------------------
1085 procedure Check_Object_Reference (P : Node_Id) is
1089 -- If we need an object, and we have a prefix that is the name of
1090 -- a function entity, convert it into a function call.
1092 if Is_Entity_Name (P)
1093 and then Ekind (Entity (P)) = E_Function
1095 Rtyp := Etype (Entity (P));
1098 Make_Function_Call (Sloc (P),
1099 Name => Relocate_Node (P)));
1101 Analyze_And_Resolve (P, Rtyp);
1103 -- Otherwise we must have an object reference
1105 elsif not Is_Object_Reference (P) then
1106 Error_Attr ("prefix of % attribute must be object", P);
1108 end Check_Object_Reference;
1110 ------------------------
1111 -- Check_Program_Unit --
1112 ------------------------
1114 procedure Check_Program_Unit is
1116 if Is_Entity_Name (P) then
1118 K : constant Entity_Kind := Ekind (Entity (P));
1119 T : constant Entity_Id := Etype (Entity (P));
1122 if K in Subprogram_Kind
1123 or else K in Task_Kind
1124 or else K in Protected_Kind
1125 or else K = E_Package
1126 or else K in Generic_Unit_Kind
1127 or else (K = E_Variable
1131 Is_Protected_Type (T)))
1138 Error_Attr ("prefix of % attribute must be program unit", P);
1139 end Check_Program_Unit;
1141 ---------------------
1142 -- Check_Real_Type --
1143 ---------------------
1145 procedure Check_Real_Type is
1149 if not Is_Real_Type (P_Type) then
1150 Error_Attr ("prefix of % attribute must be real type", P);
1152 end Check_Real_Type;
1154 -----------------------
1155 -- Check_Scalar_Type --
1156 -----------------------
1158 procedure Check_Scalar_Type is
1162 if not Is_Scalar_Type (P_Type) then
1163 Error_Attr ("prefix of % attribute must be scalar type", P);
1165 end Check_Scalar_Type;
1167 ---------------------------
1168 -- Check_Standard_Prefix --
1169 ---------------------------
1171 procedure Check_Standard_Prefix is
1175 if Nkind (P) /= N_Identifier
1176 or else Chars (P) /= Name_Standard
1178 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1181 end Check_Standard_Prefix;
1183 ----------------------------
1184 -- Check_Stream_Attribute --
1185 ----------------------------
1187 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1192 Validate_Non_Static_Attribute_Function_Call;
1194 -- With the exception of 'Input, Stream attributes are procedures,
1195 -- and can only appear at the position of procedure calls. We check
1196 -- for this here, before they are rewritten, to give a more precise
1199 if Nam = TSS_Stream_Input then
1202 elsif Is_List_Member (N)
1203 and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
1204 and then Nkind (Parent (N)) /= N_Aggregate
1210 ("invalid context for attribute%, which is a procedure", N);
1214 Btyp := Implementation_Base_Type (P_Type);
1216 -- Stream attributes not allowed on limited types unless the
1217 -- special OK_For_Stream flag is set.
1219 if Is_Limited_Type (P_Type)
1220 and then Comes_From_Source (N)
1221 and then not Present (TSS (Btyp, Nam))
1222 and then No (Get_Rep_Pragma (Btyp, Name_Stream_Convert))
1224 Error_Msg_Name_1 := Aname;
1226 ("limited type& has no% attribute", P, Btyp);
1227 Explain_Limited_Type (P_Type, P);
1230 -- Check for violation of restriction No_Stream_Attributes
1232 if Is_RTE (P_Type, RE_Exception_Id)
1234 Is_RTE (P_Type, RE_Exception_Occurrence)
1236 Check_Restriction (No_Exception_Registration, P);
1239 -- Here we must check that the first argument is an access type
1240 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1242 Analyze_And_Resolve (E1);
1245 -- Note: the double call to Root_Type here is needed because the
1246 -- root type of a class-wide type is the corresponding type (e.g.
1247 -- X for X'Class, and we really want to go to the root.
1249 if not Is_Access_Type (Etyp)
1250 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1251 RTE (RE_Root_Stream_Type)
1254 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1257 -- Check that the second argument is of the right type if there is
1258 -- one (the Input attribute has only one argument so this is skipped)
1260 if Present (E2) then
1263 if Nam = TSS_Stream_Read
1264 and then not Is_OK_Variable_For_Out_Formal (E2)
1267 ("second argument of % attribute must be a variable", E2);
1270 Resolve (E2, P_Type);
1272 end Check_Stream_Attribute;
1274 -----------------------
1275 -- Check_Task_Prefix --
1276 -----------------------
1278 procedure Check_Task_Prefix is
1282 if Is_Task_Type (Etype (P))
1283 or else (Is_Access_Type (Etype (P))
1284 and then Is_Task_Type (Designated_Type (Etype (P))))
1288 Error_Attr ("prefix of % attribute must be a task", P);
1290 end Check_Task_Prefix;
1296 -- The possibilities are an entity name denoting a type, or an
1297 -- attribute reference that denotes a type (Base or Class). If
1298 -- the type is incomplete, replace it with its full view.
1300 procedure Check_Type is
1302 if not Is_Entity_Name (P)
1303 or else not Is_Type (Entity (P))
1305 Error_Attr ("prefix of % attribute must be a type", P);
1307 elsif Ekind (Entity (P)) = E_Incomplete_Type
1308 and then Present (Full_View (Entity (P)))
1310 P_Type := Full_View (Entity (P));
1311 Set_Entity (P, P_Type);
1315 ---------------------
1316 -- Check_Unit_Name --
1317 ---------------------
1319 procedure Check_Unit_Name (Nod : Node_Id) is
1321 if Nkind (Nod) = N_Identifier then
1324 elsif Nkind (Nod) = N_Selected_Component then
1325 Check_Unit_Name (Prefix (Nod));
1327 if Nkind (Selector_Name (Nod)) = N_Identifier then
1332 Error_Attr ("argument for % attribute must be unit name", P);
1333 end Check_Unit_Name;
1339 procedure Error_Attr is
1341 Set_Etype (N, Any_Type);
1342 Set_Entity (N, Any_Type);
1343 raise Bad_Attribute;
1346 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1348 Error_Msg_Name_1 := Aname;
1349 Error_Msg_N (Msg, Error_Node);
1353 ----------------------------
1354 -- Legal_Formal_Attribute --
1355 ----------------------------
1357 procedure Legal_Formal_Attribute is
1361 if not Is_Entity_Name (P)
1362 or else not Is_Type (Entity (P))
1364 Error_Attr ("prefix of % attribute must be generic type", N);
1366 elsif Is_Generic_Actual_Type (Entity (P))
1371 elsif Is_Generic_Type (Entity (P)) then
1372 if not Is_Indefinite_Subtype (Entity (P)) then
1374 ("prefix of % attribute must be indefinite generic type", N);
1379 ("prefix of % attribute must be indefinite generic type", N);
1382 Set_Etype (N, Standard_Boolean);
1383 end Legal_Formal_Attribute;
1385 ------------------------
1386 -- Standard_Attribute --
1387 ------------------------
1389 procedure Standard_Attribute (Val : Int) is
1391 Check_Standard_Prefix;
1393 -- First a special check (more like a kludge really). For GNAT5
1394 -- on Windows, the alignments in GCC are severely mixed up. In
1395 -- particular, we have a situation where the maximum alignment
1396 -- that GCC thinks is possible is greater than the guaranteed
1397 -- alignment at run-time. That causes many problems. As a partial
1398 -- cure for this situation, we force a value of 4 for the maximum
1399 -- alignment attribute on this target. This still does not solve
1400 -- all problems, but it helps.
1402 -- A further (even more horrible) dimension to this kludge is now
1403 -- installed. There are two uses for Maximum_Alignment, one is to
1404 -- determine the maximum guaranteed alignment, that's the one we
1405 -- want the kludge to yield as 4. The other use is to maximally
1406 -- align objects, we can't use 4 here, since for example, long
1407 -- long integer has an alignment of 8, so we will get errors.
1409 -- It is of course impossible to determine which use the programmer
1410 -- has in mind, but an approximation for now is to disconnect the
1411 -- kludge if the attribute appears in an alignment clause.
1413 -- To be removed if GCC ever gets its act together here ???
1415 Alignment_Kludge : declare
1418 function On_X86 return Boolean;
1419 -- Determine if target is x86 (ia32), return True if so
1425 function On_X86 return Boolean is
1426 T : String := Sdefault.Target_Name.all;
1429 -- There is no clean way to check this. That's not surprising,
1430 -- the front end should not be doing this kind of test ???. The
1431 -- way we do it is test for either "86" or "pentium" being in
1432 -- the string for the target name.
1434 for J in T'First .. T'Last - 1 loop
1435 if T (J .. J + 1) = "86"
1436 or else (J <= T'Last - 6
1437 and then T (J .. J + 6) = "pentium")
1447 if Aname = Name_Maximum_Alignment and then On_X86 then
1450 while Nkind (P) in N_Subexpr loop
1454 if Nkind (P) /= N_Attribute_Definition_Clause
1455 or else Chars (P) /= Name_Alignment
1457 Rewrite (N, Make_Integer_Literal (Loc, 4));
1462 end Alignment_Kludge;
1464 -- Normally we get the value from gcc ???
1466 Rewrite (N, Make_Integer_Literal (Loc, Val));
1468 end Standard_Attribute;
1470 -------------------------
1471 -- Unexpected Argument --
1472 -------------------------
1474 procedure Unexpected_Argument (En : Node_Id) is
1476 Error_Attr ("unexpected argument for % attribute", En);
1477 end Unexpected_Argument;
1479 -------------------------------------------------
1480 -- Validate_Non_Static_Attribute_Function_Call --
1481 -------------------------------------------------
1483 -- This function should be moved to Sem_Dist ???
1485 procedure Validate_Non_Static_Attribute_Function_Call is
1487 if In_Preelaborated_Unit
1488 and then not In_Subprogram_Or_Concurrent_Unit
1490 Flag_Non_Static_Expr
1491 ("non-static function call in preelaborated unit!", N);
1493 end Validate_Non_Static_Attribute_Function_Call;
1495 -----------------------------------------------
1496 -- Start of Processing for Analyze_Attribute --
1497 -----------------------------------------------
1500 -- Immediate return if unrecognized attribute (already diagnosed
1501 -- by parser, so there is nothing more that we need to do)
1503 if not Is_Attribute_Name (Aname) then
1504 raise Bad_Attribute;
1507 -- Deal with Ada 83 and Features issues
1509 if Comes_From_Source (N) then
1510 if not Attribute_83 (Attr_Id) then
1511 if Ada_83 and then Comes_From_Source (N) then
1512 Error_Msg_Name_1 := Aname;
1513 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1516 if Attribute_Impl_Def (Attr_Id) then
1517 Check_Restriction (No_Implementation_Attributes, N);
1522 -- Remote access to subprogram type access attribute reference needs
1523 -- unanalyzed copy for tree transformation. The analyzed copy is used
1524 -- for its semantic information (whether prefix is a remote subprogram
1525 -- name), the unanalyzed copy is used to construct new subtree rooted
1526 -- with N_aggregate which represents a fat pointer aggregate.
1528 if Aname = Name_Access then
1529 Discard_Node (Copy_Separate_Tree (N));
1532 -- Analyze prefix and exit if error in analysis. If the prefix is an
1533 -- incomplete type, use full view if available. A special case is
1534 -- that we never analyze the prefix of an Elab_Body or Elab_Spec
1535 -- or UET_Address attribute.
1537 if Aname /= Name_Elab_Body
1539 Aname /= Name_Elab_Spec
1541 Aname /= Name_UET_Address
1544 P_Type := Etype (P);
1546 if Is_Entity_Name (P)
1547 and then Present (Entity (P))
1548 and then Is_Type (Entity (P))
1549 and then Ekind (Entity (P)) = E_Incomplete_Type
1551 P_Type := Get_Full_View (P_Type);
1552 Set_Entity (P, P_Type);
1553 Set_Etype (P, P_Type);
1556 if P_Type = Any_Type then
1557 raise Bad_Attribute;
1560 P_Base_Type := Base_Type (P_Type);
1563 -- Analyze expressions that may be present, exiting if an error occurs
1570 E1 := First (Exprs);
1573 -- Check for missing or bad expression (result of previous error)
1575 if No (E1) or else Etype (E1) = Any_Type then
1576 raise Bad_Attribute;
1581 if Present (E2) then
1584 if Etype (E2) = Any_Type then
1585 raise Bad_Attribute;
1588 if Present (Next (E2)) then
1589 Unexpected_Argument (Next (E2));
1594 if Is_Overloaded (P)
1595 and then Aname /= Name_Access
1596 and then Aname /= Name_Address
1597 and then Aname /= Name_Code_Address
1598 and then Aname /= Name_Count
1599 and then Aname /= Name_Unchecked_Access
1601 Error_Attr ("ambiguous prefix for % attribute", P);
1604 -- Remaining processing depends on attribute
1612 when Attribute_Abort_Signal =>
1613 Check_Standard_Prefix;
1615 New_Reference_To (Stand.Abort_Signal, Loc));
1622 when Attribute_Access =>
1623 Analyze_Access_Attribute;
1629 when Attribute_Address =>
1632 -- Check for some junk cases, where we have to allow the address
1633 -- attribute but it does not make much sense, so at least for now
1634 -- just replace with Null_Address.
1636 -- We also do this if the prefix is a reference to the AST_Entry
1637 -- attribute. If expansion is active, the attribute will be
1638 -- replaced by a function call, and address will work fine and
1639 -- get the proper value, but if expansion is not active, then
1640 -- the check here allows proper semantic analysis of the reference.
1642 -- An Address attribute created by expansion is legal even when it
1643 -- applies to other entity-denoting expressions.
1645 if Is_Entity_Name (P) then
1647 Ent : constant Entity_Id := Entity (P);
1650 if Is_Subprogram (Ent) then
1651 if not Is_Library_Level_Entity (Ent) then
1652 Check_Restriction (No_Implicit_Dynamic_Code, P);
1655 Set_Address_Taken (Ent);
1657 elsif Is_Object (Ent)
1658 or else Ekind (Ent) = E_Label
1660 Set_Address_Taken (Ent);
1662 -- If we have an address of an object, and the attribute
1663 -- comes from source, then set the object as potentially
1664 -- source modified. We do this because the resulting address
1665 -- can potentially be used to modify the variable and we
1666 -- might not detect this, leading to some junk warnings.
1668 Set_Never_Set_In_Source (Ent, False);
1670 elsif (Is_Concurrent_Type (Etype (Ent))
1671 and then Etype (Ent) = Base_Type (Ent))
1672 or else Ekind (Ent) = E_Package
1673 or else Is_Generic_Unit (Ent)
1676 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
1679 Error_Attr ("invalid prefix for % attribute", P);
1683 elsif Nkind (P) = N_Attribute_Reference
1684 and then Attribute_Name (P) = Name_AST_Entry
1687 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
1689 elsif Is_Object_Reference (P) then
1692 elsif Nkind (P) = N_Selected_Component
1693 and then Is_Subprogram (Entity (Selector_Name (P)))
1697 -- What exactly are we allowing here ??? and is this properly
1698 -- documented in the sinfo documentation for this node ???
1700 elsif not Comes_From_Source (N) then
1704 Error_Attr ("invalid prefix for % attribute", P);
1707 Set_Etype (N, RTE (RE_Address));
1713 when Attribute_Address_Size =>
1714 Standard_Attribute (System_Address_Size);
1720 when Attribute_Adjacent =>
1721 Check_Floating_Point_Type_2;
1722 Set_Etype (N, P_Base_Type);
1723 Resolve (E1, P_Base_Type);
1724 Resolve (E2, P_Base_Type);
1730 when Attribute_Aft =>
1731 Check_Fixed_Point_Type_0;
1732 Set_Etype (N, Universal_Integer);
1738 when Attribute_Alignment =>
1740 -- Don't we need more checking here, cf Size ???
1743 Check_Not_Incomplete_Type;
1744 Set_Etype (N, Universal_Integer);
1750 when Attribute_Asm_Input =>
1751 Check_Asm_Attribute;
1752 Set_Etype (N, RTE (RE_Asm_Input_Operand));
1758 when Attribute_Asm_Output =>
1759 Check_Asm_Attribute;
1761 if Etype (E2) = Any_Type then
1764 elsif Aname = Name_Asm_Output then
1765 if not Is_Variable (E2) then
1767 ("second argument for Asm_Output is not variable", E2);
1771 Note_Possible_Modification (E2);
1772 Set_Etype (N, RTE (RE_Asm_Output_Operand));
1778 when Attribute_AST_Entry => AST_Entry : declare
1784 -- Indicates if entry family index is present. Note the coding
1785 -- here handles the entry family case, but in fact it cannot be
1786 -- executed currently, because pragma AST_Entry does not permit
1787 -- the specification of an entry family.
1789 procedure Bad_AST_Entry;
1790 -- Signal a bad AST_Entry pragma
1792 function OK_Entry (E : Entity_Id) return Boolean;
1793 -- Checks that E is of an appropriate entity kind for an entry
1794 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
1795 -- is set True for the entry family case). In the True case,
1796 -- makes sure that Is_AST_Entry is set on the entry.
1798 procedure Bad_AST_Entry is
1800 Error_Attr ("prefix for % attribute must be task entry", P);
1803 function OK_Entry (E : Entity_Id) return Boolean is
1808 Result := (Ekind (E) = E_Entry_Family);
1810 Result := (Ekind (E) = E_Entry);
1814 if not Is_AST_Entry (E) then
1815 Error_Msg_Name_2 := Aname;
1817 ("% attribute requires previous % pragma", P);
1824 -- Start of processing for AST_Entry
1830 -- Deal with entry family case
1832 if Nkind (P) = N_Indexed_Component then
1840 Ptyp := Etype (Pref);
1842 if Ptyp = Any_Type or else Error_Posted (Pref) then
1846 -- If the prefix is a selected component whose prefix is of an
1847 -- access type, then introduce an explicit dereference.
1849 if Nkind (Pref) = N_Selected_Component
1850 and then Is_Access_Type (Ptyp)
1853 Make_Explicit_Dereference (Sloc (Pref),
1854 Relocate_Node (Pref)));
1855 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
1858 -- Prefix can be of the form a.b, where a is a task object
1859 -- and b is one of the entries of the corresponding task type.
1861 if Nkind (Pref) = N_Selected_Component
1862 and then OK_Entry (Entity (Selector_Name (Pref)))
1863 and then Is_Object_Reference (Prefix (Pref))
1864 and then Is_Task_Type (Etype (Prefix (Pref)))
1868 -- Otherwise the prefix must be an entry of a containing task,
1869 -- or of a variable of the enclosing task type.
1872 if Nkind (Pref) = N_Identifier
1873 or else Nkind (Pref) = N_Expanded_Name
1875 Ent := Entity (Pref);
1877 if not OK_Entry (Ent)
1878 or else not In_Open_Scopes (Scope (Ent))
1888 Set_Etype (N, RTE (RE_AST_Handler));
1895 -- Note: when the base attribute appears in the context of a subtype
1896 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
1897 -- the following circuit.
1899 when Attribute_Base => Base : declare
1903 Check_Either_E0_Or_E1;
1908 and then not Is_Scalar_Type (Typ)
1909 and then not Is_Generic_Type (Typ)
1911 Error_Msg_N ("prefix of Base attribute must be scalar type", N);
1913 elsif Sloc (Typ) = Standard_Location
1914 and then Base_Type (Typ) = Typ
1915 and then Warn_On_Redundant_Constructs
1918 ("?redudant attribute, & is its own base type", N, Typ);
1921 Set_Etype (N, Base_Type (Entity (P)));
1923 -- If we have an expression present, then really this is a conversion
1924 -- and the tree must be reformed. Note that this is one of the cases
1925 -- in which we do a replace rather than a rewrite, because the
1926 -- original tree is junk.
1928 if Present (E1) then
1930 Make_Type_Conversion (Loc,
1932 Make_Attribute_Reference (Loc,
1933 Prefix => Prefix (N),
1934 Attribute_Name => Name_Base),
1935 Expression => Relocate_Node (E1)));
1937 -- E1 may be overloaded, and its interpretations preserved.
1939 Save_Interps (E1, Expression (N));
1942 -- For other cases, set the proper type as the entity of the
1943 -- attribute reference, and then rewrite the node to be an
1944 -- occurrence of the referenced base type. This way, no one
1945 -- else in the compiler has to worry about the base attribute.
1948 Set_Entity (N, Base_Type (Entity (P)));
1950 New_Reference_To (Entity (N), Loc));
1959 when Attribute_Bit => Bit :
1963 if not Is_Object_Reference (P) then
1964 Error_Attr ("prefix for % attribute must be object", P);
1966 -- What about the access object cases ???
1972 Set_Etype (N, Universal_Integer);
1979 when Attribute_Bit_Order => Bit_Order :
1984 if not Is_Record_Type (P_Type) then
1985 Error_Attr ("prefix of % attribute must be record type", P);
1988 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
1990 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
1993 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
1996 Set_Etype (N, RTE (RE_Bit_Order));
1999 -- Reset incorrect indication of staticness
2001 Set_Is_Static_Expression (N, False);
2008 -- Note: in generated code, we can have a Bit_Position attribute
2009 -- applied to a (naked) record component (i.e. the prefix is an
2010 -- identifier that references an E_Component or E_Discriminant
2011 -- entity directly, and this is interpreted as expected by Gigi.
2012 -- The following code will not tolerate such usage, but when the
2013 -- expander creates this special case, it marks it as analyzed
2014 -- immediately and sets an appropriate type.
2016 when Attribute_Bit_Position =>
2018 if Comes_From_Source (N) then
2022 Set_Etype (N, Universal_Integer);
2028 when Attribute_Body_Version =>
2031 Set_Etype (N, RTE (RE_Version_String));
2037 when Attribute_Callable =>
2039 Set_Etype (N, Standard_Boolean);
2046 when Attribute_Caller => Caller : declare
2053 if Nkind (P) = N_Identifier
2054 or else Nkind (P) = N_Expanded_Name
2058 if not Is_Entry (Ent) then
2059 Error_Attr ("invalid entry name", N);
2063 Error_Attr ("invalid entry name", N);
2067 for J in reverse 0 .. Scope_Stack.Last loop
2068 S := Scope_Stack.Table (J).Entity;
2070 if S = Scope (Ent) then
2071 Error_Attr ("Caller must appear in matching accept or body", N);
2077 Set_Etype (N, RTE (RO_AT_Task_ID));
2084 when Attribute_Ceiling =>
2085 Check_Floating_Point_Type_1;
2086 Set_Etype (N, P_Base_Type);
2087 Resolve (E1, P_Base_Type);
2093 when Attribute_Class => Class : declare
2095 Check_Restriction (No_Dispatch, N);
2096 Check_Either_E0_Or_E1;
2098 -- If we have an expression present, then really this is a conversion
2099 -- and the tree must be reformed into a proper conversion. This is a
2100 -- Replace rather than a Rewrite, because the original tree is junk.
2101 -- If expression is overloaded, propagate interpretations to new one.
2103 if Present (E1) then
2105 Make_Type_Conversion (Loc,
2107 Make_Attribute_Reference (Loc,
2108 Prefix => Prefix (N),
2109 Attribute_Name => Name_Class),
2110 Expression => Relocate_Node (E1)));
2112 Save_Interps (E1, Expression (N));
2115 -- Otherwise we just need to find the proper type
2127 when Attribute_Code_Address =>
2130 if Nkind (P) = N_Attribute_Reference
2131 and then (Attribute_Name (P) = Name_Elab_Body
2133 Attribute_Name (P) = Name_Elab_Spec)
2137 elsif not Is_Entity_Name (P)
2138 or else (Ekind (Entity (P)) /= E_Function
2140 Ekind (Entity (P)) /= E_Procedure)
2142 Error_Attr ("invalid prefix for % attribute", P);
2143 Set_Address_Taken (Entity (P));
2146 Set_Etype (N, RTE (RE_Address));
2148 --------------------
2149 -- Component_Size --
2150 --------------------
2152 when Attribute_Component_Size =>
2154 Set_Etype (N, Universal_Integer);
2156 -- Note: unlike other array attributes, unconstrained arrays are OK
2158 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2168 when Attribute_Compose =>
2169 Check_Floating_Point_Type_2;
2170 Set_Etype (N, P_Base_Type);
2171 Resolve (E1, P_Base_Type);
2172 Resolve (E2, Any_Integer);
2178 when Attribute_Constrained =>
2180 Set_Etype (N, Standard_Boolean);
2182 -- Case from RM J.4(2) of constrained applied to private type
2184 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2186 -- If we are within an instance, the attribute must be legal
2187 -- because it was valid in the generic unit.
2192 -- For sure OK if we have a real private type itself, but must
2193 -- be completed, cannot apply Constrained to incomplete type.
2195 elsif Is_Private_Type (Entity (P)) then
2197 -- Note: this is one of the Annex J features that does not
2198 -- generate a warning from -gnatwj, since in fact it seems
2199 -- very useful, and is used in the GNAT runtime.
2201 Check_Not_Incomplete_Type;
2205 -- Normal (non-obsolescent case) of application to object of
2206 -- a discriminated type.
2209 Check_Object_Reference (P);
2211 -- If N does not come from source, then we allow the
2212 -- the attribute prefix to be of a private type whose
2213 -- full type has discriminants. This occurs in cases
2214 -- involving expanded calls to stream attributes.
2216 if not Comes_From_Source (N) then
2217 P_Type := Underlying_Type (P_Type);
2220 -- Must have discriminants or be an access type designating
2221 -- a type with discriminants. If it is a classwide type is
2222 -- has unknown discriminants.
2224 if Has_Discriminants (P_Type)
2225 or else Has_Unknown_Discriminants (P_Type)
2227 (Is_Access_Type (P_Type)
2228 and then Has_Discriminants (Designated_Type (P_Type)))
2232 -- Also allow an object of a generic type if extensions allowed
2233 -- and allow this for any type at all.
2235 elsif (Is_Generic_Type (P_Type)
2236 or else Is_Generic_Actual_Type (P_Type))
2237 and then Extensions_Allowed
2243 -- Fall through if bad prefix
2246 ("prefix of % attribute must be object of discriminated type", P);
2252 when Attribute_Copy_Sign =>
2253 Check_Floating_Point_Type_2;
2254 Set_Etype (N, P_Base_Type);
2255 Resolve (E1, P_Base_Type);
2256 Resolve (E2, P_Base_Type);
2262 when Attribute_Count => Count :
2271 if Nkind (P) = N_Identifier
2272 or else Nkind (P) = N_Expanded_Name
2276 if Ekind (Ent) /= E_Entry then
2277 Error_Attr ("invalid entry name", N);
2280 elsif Nkind (P) = N_Indexed_Component then
2281 if not Is_Entity_Name (Prefix (P))
2282 or else No (Entity (Prefix (P)))
2283 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2285 if Nkind (Prefix (P)) = N_Selected_Component
2286 and then Present (Entity (Selector_Name (Prefix (P))))
2287 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2291 ("attribute % must apply to entry of current task", P);
2294 Error_Attr ("invalid entry family name", P);
2299 Ent := Entity (Prefix (P));
2302 elsif Nkind (P) = N_Selected_Component
2303 and then Present (Entity (Selector_Name (P)))
2304 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2307 ("attribute % must apply to entry of current task", P);
2310 Error_Attr ("invalid entry name", N);
2314 for J in reverse 0 .. Scope_Stack.Last loop
2315 S := Scope_Stack.Table (J).Entity;
2317 if S = Scope (Ent) then
2318 if Nkind (P) = N_Expanded_Name then
2319 Tsk := Entity (Prefix (P));
2321 -- The prefix denotes either the task type, or else a
2322 -- single task whose task type is being analyzed.
2327 or else (not Is_Type (Tsk)
2328 and then Etype (Tsk) = S
2329 and then not (Comes_From_Source (S)))
2334 ("Attribute % must apply to entry of current task", N);
2340 elsif Ekind (Scope (Ent)) in Task_Kind
2341 and then Ekind (S) /= E_Loop
2342 and then Ekind (S) /= E_Block
2343 and then Ekind (S) /= E_Entry
2344 and then Ekind (S) /= E_Entry_Family
2346 Error_Attr ("Attribute % cannot appear in inner unit", N);
2348 elsif Ekind (Scope (Ent)) = E_Protected_Type
2349 and then not Has_Completion (Scope (Ent))
2351 Error_Attr ("attribute % can only be used inside body", N);
2355 if Is_Overloaded (P) then
2357 Index : Interp_Index;
2361 Get_First_Interp (P, Index, It);
2363 while Present (It.Nam) loop
2364 if It.Nam = Ent then
2368 Error_Attr ("ambiguous entry name", N);
2371 Get_Next_Interp (Index, It);
2376 Set_Etype (N, Universal_Integer);
2379 -----------------------
2380 -- Default_Bit_Order --
2381 -----------------------
2383 when Attribute_Default_Bit_Order => Default_Bit_Order :
2385 Check_Standard_Prefix;
2388 if Bytes_Big_Endian then
2390 Make_Integer_Literal (Loc, False_Value));
2393 Make_Integer_Literal (Loc, True_Value));
2396 Set_Etype (N, Universal_Integer);
2397 Set_Is_Static_Expression (N);
2398 end Default_Bit_Order;
2404 when Attribute_Definite =>
2405 Legal_Formal_Attribute;
2411 when Attribute_Delta =>
2412 Check_Fixed_Point_Type_0;
2413 Set_Etype (N, Universal_Real);
2419 when Attribute_Denorm =>
2420 Check_Floating_Point_Type_0;
2421 Set_Etype (N, Standard_Boolean);
2427 when Attribute_Digits =>
2431 if not Is_Floating_Point_Type (P_Type)
2432 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2435 ("prefix of % attribute must be float or decimal type", P);
2438 Set_Etype (N, Universal_Integer);
2444 -- Also handles processing for Elab_Spec
2446 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2448 Check_Unit_Name (P);
2449 Set_Etype (N, Standard_Void_Type);
2451 -- We have to manually call the expander in this case to get
2452 -- the necessary expansion (normally attributes that return
2453 -- entities are not expanded).
2461 -- Shares processing with Elab_Body
2467 when Attribute_Elaborated =>
2470 Set_Etype (N, Standard_Boolean);
2476 when Attribute_Emax =>
2477 Check_Floating_Point_Type_0;
2478 Set_Etype (N, Universal_Integer);
2484 when Attribute_Enum_Rep => Enum_Rep : declare
2486 if Present (E1) then
2488 Check_Discrete_Type;
2489 Resolve (E1, P_Base_Type);
2492 if not Is_Entity_Name (P)
2493 or else (not Is_Object (Entity (P))
2495 Ekind (Entity (P)) /= E_Enumeration_Literal)
2498 ("prefix of %attribute must be " &
2499 "discrete type/object or enum literal", P);
2503 Set_Etype (N, Universal_Integer);
2510 when Attribute_Epsilon =>
2511 Check_Floating_Point_Type_0;
2512 Set_Etype (N, Universal_Real);
2518 when Attribute_Exponent =>
2519 Check_Floating_Point_Type_1;
2520 Set_Etype (N, Universal_Integer);
2521 Resolve (E1, P_Base_Type);
2527 when Attribute_External_Tag =>
2531 Set_Etype (N, Standard_String);
2533 if not Is_Tagged_Type (P_Type) then
2534 Error_Attr ("prefix of % attribute must be tagged", P);
2541 when Attribute_First =>
2542 Check_Array_Or_Scalar_Type;
2548 when Attribute_First_Bit =>
2550 Set_Etype (N, Universal_Integer);
2556 when Attribute_Fixed_Value =>
2558 Check_Fixed_Point_Type;
2559 Resolve (E1, Any_Integer);
2560 Set_Etype (N, P_Base_Type);
2566 when Attribute_Floor =>
2567 Check_Floating_Point_Type_1;
2568 Set_Etype (N, P_Base_Type);
2569 Resolve (E1, P_Base_Type);
2575 when Attribute_Fore =>
2576 Check_Fixed_Point_Type_0;
2577 Set_Etype (N, Universal_Integer);
2583 when Attribute_Fraction =>
2584 Check_Floating_Point_Type_1;
2585 Set_Etype (N, P_Base_Type);
2586 Resolve (E1, P_Base_Type);
2588 -----------------------
2589 -- Has_Discriminants --
2590 -----------------------
2592 when Attribute_Has_Discriminants =>
2593 Legal_Formal_Attribute;
2599 when Attribute_Identity =>
2603 if Etype (P) = Standard_Exception_Type then
2604 Set_Etype (N, RTE (RE_Exception_Id));
2606 elsif Is_Task_Type (Etype (P))
2607 or else (Is_Access_Type (Etype (P))
2608 and then Is_Task_Type (Designated_Type (Etype (P))))
2611 Set_Etype (N, RTE (RO_AT_Task_ID));
2614 Error_Attr ("prefix of % attribute must be a task or an "
2622 when Attribute_Image => Image :
2624 Set_Etype (N, Standard_String);
2627 if Is_Real_Type (P_Type) then
2628 if Ada_83 and then Comes_From_Source (N) then
2629 Error_Msg_Name_1 := Aname;
2631 ("(Ada 83) % attribute not allowed for real types", N);
2635 if Is_Enumeration_Type (P_Type) then
2636 Check_Restriction (No_Enumeration_Maps, N);
2640 Resolve (E1, P_Base_Type);
2642 Validate_Non_Static_Attribute_Function_Call;
2649 when Attribute_Img => Img :
2651 Set_Etype (N, Standard_String);
2653 if not Is_Scalar_Type (P_Type)
2654 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
2657 ("prefix of % attribute must be scalar object name", N);
2667 when Attribute_Input =>
2669 Check_Stream_Attribute (TSS_Stream_Input);
2670 Set_Etype (N, P_Base_Type);
2676 when Attribute_Integer_Value =>
2679 Resolve (E1, Any_Fixed);
2680 Set_Etype (N, P_Base_Type);
2686 when Attribute_Large =>
2689 Set_Etype (N, Universal_Real);
2695 when Attribute_Last =>
2696 Check_Array_Or_Scalar_Type;
2702 when Attribute_Last_Bit =>
2704 Set_Etype (N, Universal_Integer);
2710 when Attribute_Leading_Part =>
2711 Check_Floating_Point_Type_2;
2712 Set_Etype (N, P_Base_Type);
2713 Resolve (E1, P_Base_Type);
2714 Resolve (E2, Any_Integer);
2720 when Attribute_Length =>
2722 Set_Etype (N, Universal_Integer);
2728 when Attribute_Machine =>
2729 Check_Floating_Point_Type_1;
2730 Set_Etype (N, P_Base_Type);
2731 Resolve (E1, P_Base_Type);
2737 when Attribute_Machine_Emax =>
2738 Check_Floating_Point_Type_0;
2739 Set_Etype (N, Universal_Integer);
2745 when Attribute_Machine_Emin =>
2746 Check_Floating_Point_Type_0;
2747 Set_Etype (N, Universal_Integer);
2749 ----------------------
2750 -- Machine_Mantissa --
2751 ----------------------
2753 when Attribute_Machine_Mantissa =>
2754 Check_Floating_Point_Type_0;
2755 Set_Etype (N, Universal_Integer);
2757 -----------------------
2758 -- Machine_Overflows --
2759 -----------------------
2761 when Attribute_Machine_Overflows =>
2764 Set_Etype (N, Standard_Boolean);
2770 when Attribute_Machine_Radix =>
2773 Set_Etype (N, Universal_Integer);
2775 --------------------
2776 -- Machine_Rounds --
2777 --------------------
2779 when Attribute_Machine_Rounds =>
2782 Set_Etype (N, Standard_Boolean);
2788 when Attribute_Machine_Size =>
2791 Check_Not_Incomplete_Type;
2792 Set_Etype (N, Universal_Integer);
2798 when Attribute_Mantissa =>
2801 Set_Etype (N, Universal_Integer);
2807 when Attribute_Max =>
2810 Resolve (E1, P_Base_Type);
2811 Resolve (E2, P_Base_Type);
2812 Set_Etype (N, P_Base_Type);
2814 ----------------------------------
2815 -- Max_Size_In_Storage_Elements --
2816 ----------------------------------
2818 when Attribute_Max_Size_In_Storage_Elements =>
2821 Check_Not_Incomplete_Type;
2822 Set_Etype (N, Universal_Integer);
2824 -----------------------
2825 -- Maximum_Alignment --
2826 -----------------------
2828 when Attribute_Maximum_Alignment =>
2829 Standard_Attribute (Ttypes.Maximum_Alignment);
2831 --------------------
2832 -- Mechanism_Code --
2833 --------------------
2835 when Attribute_Mechanism_Code =>
2836 if not Is_Entity_Name (P)
2837 or else not Is_Subprogram (Entity (P))
2839 Error_Attr ("prefix of % attribute must be subprogram", P);
2842 Check_Either_E0_Or_E1;
2844 if Present (E1) then
2845 Resolve (E1, Any_Integer);
2846 Set_Etype (E1, Standard_Integer);
2848 if not Is_Static_Expression (E1) then
2849 Flag_Non_Static_Expr
2850 ("expression for parameter number must be static!", E1);
2853 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
2854 or else UI_To_Int (Intval (E1)) < 0
2856 Error_Attr ("invalid parameter number for %attribute", E1);
2860 Set_Etype (N, Universal_Integer);
2866 when Attribute_Min =>
2869 Resolve (E1, P_Base_Type);
2870 Resolve (E2, P_Base_Type);
2871 Set_Etype (N, P_Base_Type);
2877 when Attribute_Model =>
2878 Check_Floating_Point_Type_1;
2879 Set_Etype (N, P_Base_Type);
2880 Resolve (E1, P_Base_Type);
2886 when Attribute_Model_Emin =>
2887 Check_Floating_Point_Type_0;
2888 Set_Etype (N, Universal_Integer);
2894 when Attribute_Model_Epsilon =>
2895 Check_Floating_Point_Type_0;
2896 Set_Etype (N, Universal_Real);
2898 --------------------
2899 -- Model_Mantissa --
2900 --------------------
2902 when Attribute_Model_Mantissa =>
2903 Check_Floating_Point_Type_0;
2904 Set_Etype (N, Universal_Integer);
2910 when Attribute_Model_Small =>
2911 Check_Floating_Point_Type_0;
2912 Set_Etype (N, Universal_Real);
2918 when Attribute_Modulus =>
2922 if not Is_Modular_Integer_Type (P_Type) then
2923 Error_Attr ("prefix of % attribute must be modular type", P);
2926 Set_Etype (N, Universal_Integer);
2928 --------------------
2929 -- Null_Parameter --
2930 --------------------
2932 when Attribute_Null_Parameter => Null_Parameter : declare
2933 Parnt : constant Node_Id := Parent (N);
2934 GParnt : constant Node_Id := Parent (Parnt);
2936 procedure Bad_Null_Parameter (Msg : String);
2937 -- Used if bad Null parameter attribute node is found. Issues
2938 -- given error message, and also sets the type to Any_Type to
2939 -- avoid blowups later on from dealing with a junk node.
2941 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
2942 -- Called to check that Proc_Ent is imported subprogram
2944 ------------------------
2945 -- Bad_Null_Parameter --
2946 ------------------------
2948 procedure Bad_Null_Parameter (Msg : String) is
2950 Error_Msg_N (Msg, N);
2951 Set_Etype (N, Any_Type);
2952 end Bad_Null_Parameter;
2954 ----------------------
2955 -- Must_Be_Imported --
2956 ----------------------
2958 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
2959 Pent : Entity_Id := Proc_Ent;
2962 while Present (Alias (Pent)) loop
2963 Pent := Alias (Pent);
2966 -- Ignore check if procedure not frozen yet (we will get
2967 -- another chance when the default parameter is reanalyzed)
2969 if not Is_Frozen (Pent) then
2972 elsif not Is_Imported (Pent) then
2974 ("Null_Parameter can only be used with imported subprogram");
2979 end Must_Be_Imported;
2981 -- Start of processing for Null_Parameter
2986 Set_Etype (N, P_Type);
2988 -- Case of attribute used as default expression
2990 if Nkind (Parnt) = N_Parameter_Specification then
2991 Must_Be_Imported (Defining_Entity (GParnt));
2993 -- Case of attribute used as actual for subprogram (positional)
2995 elsif (Nkind (Parnt) = N_Procedure_Call_Statement
2997 Nkind (Parnt) = N_Function_Call)
2998 and then Is_Entity_Name (Name (Parnt))
3000 Must_Be_Imported (Entity (Name (Parnt)));
3002 -- Case of attribute used as actual for subprogram (named)
3004 elsif Nkind (Parnt) = N_Parameter_Association
3005 and then (Nkind (GParnt) = N_Procedure_Call_Statement
3007 Nkind (GParnt) = N_Function_Call)
3008 and then Is_Entity_Name (Name (GParnt))
3010 Must_Be_Imported (Entity (Name (GParnt)));
3012 -- Not an allowed case
3016 ("Null_Parameter must be actual or default parameter");
3025 when Attribute_Object_Size =>
3028 Check_Not_Incomplete_Type;
3029 Set_Etype (N, Universal_Integer);
3035 when Attribute_Output =>
3037 Check_Stream_Attribute (TSS_Stream_Output);
3038 Set_Etype (N, Standard_Void_Type);
3039 Resolve (N, Standard_Void_Type);
3045 when Attribute_Partition_ID =>
3048 if P_Type /= Any_Type then
3049 if not Is_Library_Level_Entity (Entity (P)) then
3051 ("prefix of % attribute must be library-level entity", P);
3053 -- The defining entity of prefix should not be declared inside
3054 -- a Pure unit. RM E.1(8).
3055 -- The Is_Pure flag has been set during declaration.
3057 elsif Is_Entity_Name (P)
3058 and then Is_Pure (Entity (P))
3061 ("prefix of % attribute must not be declared pure", P);
3065 Set_Etype (N, Universal_Integer);
3067 -------------------------
3068 -- Passed_By_Reference --
3069 -------------------------
3071 when Attribute_Passed_By_Reference =>
3074 Set_Etype (N, Standard_Boolean);
3080 when Attribute_Pool_Address =>
3082 Set_Etype (N, RTE (RE_Address));
3088 when Attribute_Pos =>
3089 Check_Discrete_Type;
3091 Resolve (E1, P_Base_Type);
3092 Set_Etype (N, Universal_Integer);
3098 when Attribute_Position =>
3100 Set_Etype (N, Universal_Integer);
3106 when Attribute_Pred =>
3109 Resolve (E1, P_Base_Type);
3110 Set_Etype (N, P_Base_Type);
3112 -- Nothing to do for real type case
3114 if Is_Real_Type (P_Type) then
3117 -- If not modular type, test for overflow check required
3120 if not Is_Modular_Integer_Type (P_Type)
3121 and then not Range_Checks_Suppressed (P_Base_Type)
3123 Enable_Range_Check (E1);
3131 when Attribute_Range =>
3132 Check_Array_Or_Scalar_Type;
3135 and then Is_Scalar_Type (P_Type)
3136 and then Comes_From_Source (N)
3139 ("(Ada 83) % attribute not allowed for scalar type", P);
3146 when Attribute_Range_Length =>
3147 Check_Discrete_Type;
3148 Set_Etype (N, Universal_Integer);
3154 when Attribute_Read =>
3156 Check_Stream_Attribute (TSS_Stream_Read);
3157 Set_Etype (N, Standard_Void_Type);
3158 Resolve (N, Standard_Void_Type);
3159 Note_Possible_Modification (E2);
3165 when Attribute_Remainder =>
3166 Check_Floating_Point_Type_2;
3167 Set_Etype (N, P_Base_Type);
3168 Resolve (E1, P_Base_Type);
3169 Resolve (E2, P_Base_Type);
3175 when Attribute_Round =>
3177 Check_Decimal_Fixed_Point_Type;
3178 Set_Etype (N, P_Base_Type);
3180 -- Because the context is universal_real (3.5.10(12)) it is a legal
3181 -- context for a universal fixed expression. This is the only
3182 -- attribute whose functional description involves U_R.
3184 if Etype (E1) = Universal_Fixed then
3186 Conv : constant Node_Id := Make_Type_Conversion (Loc,
3187 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
3188 Expression => Relocate_Node (E1));
3196 Resolve (E1, Any_Real);
3202 when Attribute_Rounding =>
3203 Check_Floating_Point_Type_1;
3204 Set_Etype (N, P_Base_Type);
3205 Resolve (E1, P_Base_Type);
3211 when Attribute_Safe_Emax =>
3212 Check_Floating_Point_Type_0;
3213 Set_Etype (N, Universal_Integer);
3219 when Attribute_Safe_First =>
3220 Check_Floating_Point_Type_0;
3221 Set_Etype (N, Universal_Real);
3227 when Attribute_Safe_Large =>
3230 Set_Etype (N, Universal_Real);
3236 when Attribute_Safe_Last =>
3237 Check_Floating_Point_Type_0;
3238 Set_Etype (N, Universal_Real);
3244 when Attribute_Safe_Small =>
3247 Set_Etype (N, Universal_Real);
3253 when Attribute_Scale =>
3255 Check_Decimal_Fixed_Point_Type;
3256 Set_Etype (N, Universal_Integer);
3262 when Attribute_Scaling =>
3263 Check_Floating_Point_Type_2;
3264 Set_Etype (N, P_Base_Type);
3265 Resolve (E1, P_Base_Type);
3271 when Attribute_Signed_Zeros =>
3272 Check_Floating_Point_Type_0;
3273 Set_Etype (N, Standard_Boolean);
3279 when Attribute_Size | Attribute_VADS_Size =>
3282 if Is_Object_Reference (P)
3283 or else (Is_Entity_Name (P)
3284 and then Ekind (Entity (P)) = E_Function)
3286 Check_Object_Reference (P);
3288 elsif Is_Entity_Name (P)
3289 and then Is_Type (Entity (P))
3293 elsif Nkind (P) = N_Type_Conversion
3294 and then not Comes_From_Source (P)
3299 Error_Attr ("invalid prefix for % attribute", P);
3302 Check_Not_Incomplete_Type;
3303 Set_Etype (N, Universal_Integer);
3309 when Attribute_Small =>
3312 Set_Etype (N, Universal_Real);
3318 when Attribute_Storage_Pool =>
3319 if Is_Access_Type (P_Type) then
3322 -- Set appropriate entity
3324 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
3325 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
3327 Set_Entity (N, RTE (RE_Global_Pool_Object));
3330 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
3332 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
3333 -- Storage_Pool since this attribute is not defined for such
3334 -- types (RM E.2.3(22)).
3336 Validate_Remote_Access_To_Class_Wide_Type (N);
3339 Error_Attr ("prefix of % attribute must be access type", P);
3346 when Attribute_Storage_Size =>
3348 if Is_Task_Type (P_Type) then
3350 Set_Etype (N, Universal_Integer);
3352 elsif Is_Access_Type (P_Type) then
3353 if Is_Entity_Name (P)
3354 and then Is_Type (Entity (P))
3358 Set_Etype (N, Universal_Integer);
3360 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
3361 -- Storage_Size since this attribute is not defined for
3362 -- such types (RM E.2.3(22)).
3364 Validate_Remote_Access_To_Class_Wide_Type (N);
3366 -- The prefix is allowed to be an implicit dereference
3367 -- of an access value designating a task.
3372 Set_Etype (N, Universal_Integer);
3377 ("prefix of % attribute must be access or task type", P);
3384 when Attribute_Storage_Unit =>
3385 Standard_Attribute (Ttypes.System_Storage_Unit);
3391 when Attribute_Succ =>
3394 Resolve (E1, P_Base_Type);
3395 Set_Etype (N, P_Base_Type);
3397 -- Nothing to do for real type case
3399 if Is_Real_Type (P_Type) then
3402 -- If not modular type, test for overflow check required.
3405 if not Is_Modular_Integer_Type (P_Type)
3406 and then not Range_Checks_Suppressed (P_Base_Type)
3408 Enable_Range_Check (E1);
3416 when Attribute_Tag =>
3420 if not Is_Tagged_Type (P_Type) then
3421 Error_Attr ("prefix of % attribute must be tagged", P);
3423 -- Next test does not apply to generated code
3424 -- why not, and what does the illegal reference mean???
3426 elsif Is_Object_Reference (P)
3427 and then not Is_Class_Wide_Type (P_Type)
3428 and then Comes_From_Source (N)
3431 ("% attribute can only be applied to objects of class-wide type",
3435 Set_Etype (N, RTE (RE_Tag));
3441 when Attribute_Target_Name => Target_Name : declare
3442 TN : constant String := Sdefault.Target_Name.all;
3443 TL : Integer := TN'Last;
3446 Check_Standard_Prefix;
3450 if TN (TL) = '/' or else TN (TL) = '\' then
3454 Store_String_Chars (TN (TN'First .. TL));
3457 Make_String_Literal (Loc,
3458 Strval => End_String));
3459 Analyze_And_Resolve (N, Standard_String);
3466 when Attribute_Terminated =>
3468 Set_Etype (N, Standard_Boolean);
3475 when Attribute_To_Address =>
3479 if Nkind (P) /= N_Identifier
3480 or else Chars (P) /= Name_System
3482 Error_Attr ("prefix of %attribute must be System", P);
3485 Generate_Reference (RTE (RE_Address), P);
3486 Analyze_And_Resolve (E1, Any_Integer);
3487 Set_Etype (N, RTE (RE_Address));
3493 when Attribute_Truncation =>
3494 Check_Floating_Point_Type_1;
3495 Resolve (E1, P_Base_Type);
3496 Set_Etype (N, P_Base_Type);
3502 when Attribute_Type_Class =>
3505 Check_Not_Incomplete_Type;
3506 Set_Etype (N, RTE (RE_Type_Class));
3512 when Attribute_UET_Address =>
3514 Check_Unit_Name (P);
3515 Set_Etype (N, RTE (RE_Address));
3517 -----------------------
3518 -- Unbiased_Rounding --
3519 -----------------------
3521 when Attribute_Unbiased_Rounding =>
3522 Check_Floating_Point_Type_1;
3523 Set_Etype (N, P_Base_Type);
3524 Resolve (E1, P_Base_Type);
3526 ----------------------
3527 -- Unchecked_Access --
3528 ----------------------
3530 when Attribute_Unchecked_Access =>
3531 if Comes_From_Source (N) then
3532 Check_Restriction (No_Unchecked_Access, N);
3535 Analyze_Access_Attribute;
3537 -------------------------
3538 -- Unconstrained_Array --
3539 -------------------------
3541 when Attribute_Unconstrained_Array =>
3544 Check_Not_Incomplete_Type;
3545 Set_Etype (N, Standard_Boolean);
3547 ------------------------------
3548 -- Universal_Literal_String --
3549 ------------------------------
3551 -- This is a GNAT specific attribute whose prefix must be a named
3552 -- number where the expression is either a single numeric literal,
3553 -- or a numeric literal immediately preceded by a minus sign. The
3554 -- result is equivalent to a string literal containing the text of
3555 -- the literal as it appeared in the source program with a possible
3556 -- leading minus sign.
3558 when Attribute_Universal_Literal_String => Universal_Literal_String :
3562 if not Is_Entity_Name (P)
3563 or else Ekind (Entity (P)) not in Named_Kind
3565 Error_Attr ("prefix for % attribute must be named number", P);
3572 Src : Source_Buffer_Ptr;
3575 Expr := Original_Node (Expression (Parent (Entity (P))));
3577 if Nkind (Expr) = N_Op_Minus then
3579 Expr := Original_Node (Right_Opnd (Expr));
3584 if Nkind (Expr) /= N_Integer_Literal
3585 and then Nkind (Expr) /= N_Real_Literal
3588 ("named number for % attribute must be simple literal", N);
3591 -- Build string literal corresponding to source literal text
3596 Store_String_Char (Get_Char_Code ('-'));
3600 Src := Source_Text (Get_Source_File_Index (S));
3602 while Src (S) /= ';' and then Src (S) /= ' ' loop
3603 Store_String_Char (Get_Char_Code (Src (S)));
3607 -- Now we rewrite the attribute with the string literal
3610 Make_String_Literal (Loc, End_String));
3614 end Universal_Literal_String;
3616 -------------------------
3617 -- Unrestricted_Access --
3618 -------------------------
3620 -- This is a GNAT specific attribute which is like Access except that
3621 -- all scope checks and checks for aliased views are omitted.
3623 when Attribute_Unrestricted_Access =>
3624 if Comes_From_Source (N) then
3625 Check_Restriction (No_Unchecked_Access, N);
3628 if Is_Entity_Name (P) then
3629 Set_Address_Taken (Entity (P));
3632 Analyze_Access_Attribute;
3638 when Attribute_Val => Val : declare
3641 Check_Discrete_Type;
3642 Resolve (E1, Any_Integer);
3643 Set_Etype (N, P_Base_Type);
3645 -- Note, we need a range check in general, but we wait for the
3646 -- Resolve call to do this, since we want to let Eval_Attribute
3647 -- have a chance to find an static illegality first!
3654 when Attribute_Valid =>
3657 -- Ignore check for object if we have a 'Valid reference generated
3658 -- by the expanded code, since in some cases valid checks can occur
3659 -- on items that are names, but are not objects (e.g. attributes).
3661 if Comes_From_Source (N) then
3662 Check_Object_Reference (P);
3665 if not Is_Scalar_Type (P_Type) then
3666 Error_Attr ("object for % attribute must be of scalar type", P);
3669 Set_Etype (N, Standard_Boolean);
3675 when Attribute_Value => Value :
3680 if Is_Enumeration_Type (P_Type) then
3681 Check_Restriction (No_Enumeration_Maps, N);
3684 -- Set Etype before resolving expression because expansion of
3685 -- expression may require enclosing type. Note that the type
3686 -- returned by 'Value is the base type of the prefix type.
3688 Set_Etype (N, P_Base_Type);
3689 Validate_Non_Static_Attribute_Function_Call;
3696 when Attribute_Value_Size =>
3699 Check_Not_Incomplete_Type;
3700 Set_Etype (N, Universal_Integer);
3706 when Attribute_Version =>
3709 Set_Etype (N, RTE (RE_Version_String));
3715 when Attribute_Wchar_T_Size =>
3716 Standard_Attribute (Interfaces_Wchar_T_Size);
3722 when Attribute_Wide_Image => Wide_Image :
3725 Set_Etype (N, Standard_Wide_String);
3727 Resolve (E1, P_Base_Type);
3728 Validate_Non_Static_Attribute_Function_Call;
3735 when Attribute_Wide_Value => Wide_Value :
3740 -- Set Etype before resolving expression because expansion
3741 -- of expression may require enclosing type.
3743 Set_Etype (N, P_Type);
3744 Validate_Non_Static_Attribute_Function_Call;
3751 when Attribute_Wide_Width =>
3754 Set_Etype (N, Universal_Integer);
3760 when Attribute_Width =>
3763 Set_Etype (N, Universal_Integer);
3769 when Attribute_Word_Size =>
3770 Standard_Attribute (System_Word_Size);
3776 when Attribute_Write =>
3778 Check_Stream_Attribute (TSS_Stream_Write);
3779 Set_Etype (N, Standard_Void_Type);
3780 Resolve (N, Standard_Void_Type);
3784 -- All errors raise Bad_Attribute, so that we get out before any further
3785 -- damage occurs when an error is detected (for example, if we check for
3786 -- one attribute expression, and the check succeeds, we want to be able
3787 -- to proceed securely assuming that an expression is in fact present.
3790 when Bad_Attribute =>
3791 Set_Etype (N, Any_Type);
3794 end Analyze_Attribute;
3796 --------------------
3797 -- Eval_Attribute --
3798 --------------------
3800 procedure Eval_Attribute (N : Node_Id) is
3801 Loc : constant Source_Ptr := Sloc (N);
3802 Aname : constant Name_Id := Attribute_Name (N);
3803 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
3804 P : constant Node_Id := Prefix (N);
3806 C_Type : constant Entity_Id := Etype (N);
3807 -- The type imposed by the context.
3810 -- First expression, or Empty if none
3813 -- Second expression, or Empty if none
3815 P_Entity : Entity_Id;
3816 -- Entity denoted by prefix
3819 -- The type of the prefix
3821 P_Base_Type : Entity_Id;
3822 -- The base type of the prefix type
3824 P_Root_Type : Entity_Id;
3825 -- The root type of the prefix type
3828 -- True if the result is Static. This is set by the general processing
3829 -- to true if the prefix is static, and all expressions are static. It
3830 -- can be reset as processing continues for particular attributes
3832 Lo_Bound, Hi_Bound : Node_Id;
3833 -- Expressions for low and high bounds of type or array index referenced
3834 -- by First, Last, or Length attribute for array, set by Set_Bounds.
3837 -- Constraint error node used if we have an attribute reference has
3838 -- an argument that raises a constraint error. In this case we replace
3839 -- the attribute with a raise constraint_error node. This is important
3840 -- processing, since otherwise gigi might see an attribute which it is
3841 -- unprepared to deal with.
3843 function Aft_Value return Nat;
3844 -- Computes Aft value for current attribute prefix (used by Aft itself
3845 -- and also by Width for computing the Width of a fixed point type).
3847 procedure Check_Expressions;
3848 -- In case where the attribute is not foldable, the expressions, if
3849 -- any, of the attribute, are in a non-static context. This procedure
3850 -- performs the required additional checks.
3852 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
3853 -- Determines if the given type has compile time known bounds. Note
3854 -- that we enter the case statement even in cases where the prefix
3855 -- type does NOT have known bounds, so it is important to guard any
3856 -- attempt to evaluate both bounds with a call to this function.
3858 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
3859 -- This procedure is called when the attribute N has a non-static
3860 -- but compile time known value given by Val. It includes the
3861 -- necessary checks for out of range values.
3863 procedure Float_Attribute_Universal_Integer
3872 -- This procedure evaluates a float attribute with no arguments that
3873 -- returns a universal integer result. The parameters give the values
3874 -- for the possible floating-point root types. See ttypef for details.
3875 -- The prefix type is a float type (and is thus not a generic type).
3877 procedure Float_Attribute_Universal_Real
3878 (IEEES_Val : String;
3885 AAMPL_Val : String);
3886 -- This procedure evaluates a float attribute with no arguments that
3887 -- returns a universal real result. The parameters give the values
3888 -- required for the possible floating-point root types in string
3889 -- format as real literals with a possible leading minus sign.
3890 -- The prefix type is a float type (and is thus not a generic type).
3892 function Fore_Value return Nat;
3893 -- Computes the Fore value for the current attribute prefix, which is
3894 -- known to be a static fixed-point type. Used by Fore and Width.
3896 function Mantissa return Uint;
3897 -- Returns the Mantissa value for the prefix type
3899 procedure Set_Bounds;
3900 -- Used for First, Last and Length attributes applied to an array or
3901 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
3902 -- and high bound expressions for the index referenced by the attribute
3903 -- designator (i.e. the first index if no expression is present, and
3904 -- the N'th index if the value N is present as an expression). Also
3905 -- used for First and Last of scalar types. Static is reset to False
3906 -- if the type or index type is not statically constrained.
3912 function Aft_Value return Nat is
3918 Delta_Val := Delta_Value (P_Type);
3920 while Delta_Val < Ureal_Tenth loop
3921 Delta_Val := Delta_Val * Ureal_10;
3922 Result := Result + 1;
3928 -----------------------
3929 -- Check_Expressions --
3930 -----------------------
3932 procedure Check_Expressions is
3936 while Present (E) loop
3937 Check_Non_Static_Context (E);
3940 end Check_Expressions;
3942 ----------------------------------
3943 -- Compile_Time_Known_Attribute --
3944 ----------------------------------
3946 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
3947 T : constant Entity_Id := Etype (N);
3950 Fold_Uint (N, Val, False);
3952 -- Check that result is in bounds of the type if it is static
3954 if Is_In_Range (N, T) then
3957 elsif Is_Out_Of_Range (N, T) then
3958 Apply_Compile_Time_Constraint_Error
3959 (N, "value not in range of}?", CE_Range_Check_Failed);
3961 elsif not Range_Checks_Suppressed (T) then
3962 Enable_Range_Check (N);
3965 Set_Do_Range_Check (N, False);
3967 end Compile_Time_Known_Attribute;
3969 -------------------------------
3970 -- Compile_Time_Known_Bounds --
3971 -------------------------------
3973 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
3976 Compile_Time_Known_Value (Type_Low_Bound (Typ))
3978 Compile_Time_Known_Value (Type_High_Bound (Typ));
3979 end Compile_Time_Known_Bounds;
3981 ---------------------------------------
3982 -- Float_Attribute_Universal_Integer --
3983 ---------------------------------------
3985 procedure Float_Attribute_Universal_Integer
3996 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
3999 if Vax_Float (P_Base_Type) then
4000 if Digs = VAXFF_Digits then
4002 elsif Digs = VAXDF_Digits then
4004 else pragma Assert (Digs = VAXGF_Digits);
4008 elsif Is_AAMP_Float (P_Base_Type) then
4009 if Digs = AAMPS_Digits then
4011 else pragma Assert (Digs = AAMPL_Digits);
4016 if Digs = IEEES_Digits then
4018 elsif Digs = IEEEL_Digits then
4020 else pragma Assert (Digs = IEEEX_Digits);
4025 Fold_Uint (N, UI_From_Int (Val), True);
4026 end Float_Attribute_Universal_Integer;
4028 ------------------------------------
4029 -- Float_Attribute_Universal_Real --
4030 ------------------------------------
4032 procedure Float_Attribute_Universal_Real
4033 (IEEES_Val : String;
4043 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4046 if Vax_Float (P_Base_Type) then
4047 if Digs = VAXFF_Digits then
4048 Val := Real_Convert (VAXFF_Val);
4049 elsif Digs = VAXDF_Digits then
4050 Val := Real_Convert (VAXDF_Val);
4051 else pragma Assert (Digs = VAXGF_Digits);
4052 Val := Real_Convert (VAXGF_Val);
4055 elsif Is_AAMP_Float (P_Base_Type) then
4056 if Digs = AAMPS_Digits then
4057 Val := Real_Convert (AAMPS_Val);
4058 else pragma Assert (Digs = AAMPL_Digits);
4059 Val := Real_Convert (AAMPL_Val);
4063 if Digs = IEEES_Digits then
4064 Val := Real_Convert (IEEES_Val);
4065 elsif Digs = IEEEL_Digits then
4066 Val := Real_Convert (IEEEL_Val);
4067 else pragma Assert (Digs = IEEEX_Digits);
4068 Val := Real_Convert (IEEEX_Val);
4072 Set_Sloc (Val, Loc);
4074 Set_Is_Static_Expression (N, Static);
4075 Analyze_And_Resolve (N, C_Type);
4076 end Float_Attribute_Universal_Real;
4082 -- Note that the Fore calculation is based on the actual values
4083 -- of the bounds, and does not take into account possible rounding.
4085 function Fore_Value return Nat is
4086 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
4087 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
4088 Small : constant Ureal := Small_Value (P_Type);
4089 Lo_Real : constant Ureal := Lo * Small;
4090 Hi_Real : constant Ureal := Hi * Small;
4095 -- Bounds are given in terms of small units, so first compute
4096 -- proper values as reals.
4098 T := UR_Max (abs Lo_Real, abs Hi_Real);
4101 -- Loop to compute proper value if more than one digit required
4103 while T >= Ureal_10 loop
4115 -- Table of mantissa values accessed by function Computed using
4118 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
4120 -- where D is T'Digits (RM83 3.5.7)
4122 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
4164 function Mantissa return Uint is
4167 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
4174 procedure Set_Bounds is
4180 -- For a string literal subtype, we have to construct the bounds.
4181 -- Valid Ada code never applies attributes to string literals, but
4182 -- it is convenient to allow the expander to generate attribute
4183 -- references of this type (e.g. First and Last applied to a string
4186 -- Note that the whole point of the E_String_Literal_Subtype is to
4187 -- avoid this construction of bounds, but the cases in which we
4188 -- have to materialize them are rare enough that we don't worry!
4190 -- The low bound is simply the low bound of the base type. The
4191 -- high bound is computed from the length of the string and this
4194 if Ekind (P_Type) = E_String_Literal_Subtype then
4195 Ityp := Etype (First_Index (Base_Type (P_Type)));
4196 Lo_Bound := Type_Low_Bound (Ityp);
4199 Make_Integer_Literal (Sloc (P),
4201 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
4203 Set_Parent (Hi_Bound, P);
4204 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
4207 -- For non-array case, just get bounds of scalar type
4209 elsif Is_Scalar_Type (P_Type) then
4212 -- For a fixed-point type, we must freeze to get the attributes
4213 -- of the fixed-point type set now so we can reference them.
4215 if Is_Fixed_Point_Type (P_Type)
4216 and then not Is_Frozen (Base_Type (P_Type))
4217 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
4218 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
4220 Freeze_Fixed_Point_Type (Base_Type (P_Type));
4223 -- For array case, get type of proper index
4229 Ndim := UI_To_Int (Expr_Value (E1));
4232 Indx := First_Index (P_Type);
4233 for J in 1 .. Ndim - 1 loop
4237 -- If no index type, get out (some other error occurred, and
4238 -- we don't have enough information to complete the job!)
4246 Ityp := Etype (Indx);
4249 -- A discrete range in an index constraint is allowed to be a
4250 -- subtype indication. This is syntactically a pain, but should
4251 -- not propagate to the entity for the corresponding index subtype.
4252 -- After checking that the subtype indication is legal, the range
4253 -- of the subtype indication should be transfered to the entity.
4254 -- The attributes for the bounds should remain the simple retrievals
4255 -- that they are now.
4257 Lo_Bound := Type_Low_Bound (Ityp);
4258 Hi_Bound := Type_High_Bound (Ityp);
4260 if not Is_Static_Subtype (Ityp) then
4265 -- Start of processing for Eval_Attribute
4268 -- Acquire first two expressions (at the moment, no attributes
4269 -- take more than two expressions in any case).
4271 if Present (Expressions (N)) then
4272 E1 := First (Expressions (N));
4279 -- Special processing for cases where the prefix is an object. For
4280 -- this purpose, a string literal counts as an object (attributes
4281 -- of string literals can only appear in generated code).
4283 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
4285 -- For Component_Size, the prefix is an array object, and we apply
4286 -- the attribute to the type of the object. This is allowed for
4287 -- both unconstrained and constrained arrays, since the bounds
4288 -- have no influence on the value of this attribute.
4290 if Id = Attribute_Component_Size then
4291 P_Entity := Etype (P);
4293 -- For First and Last, the prefix is an array object, and we apply
4294 -- the attribute to the type of the array, but we need a constrained
4295 -- type for this, so we use the actual subtype if available.
4297 elsif Id = Attribute_First
4301 Id = Attribute_Length
4304 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
4307 if Present (AS) and then Is_Constrained (AS) then
4310 -- If we have an unconstrained type, cannot fold
4318 -- For Size, give size of object if available, otherwise we
4319 -- cannot fold Size.
4321 elsif Id = Attribute_Size then
4322 if Is_Entity_Name (P)
4323 and then Known_Esize (Entity (P))
4325 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
4333 -- For Alignment, give size of object if available, otherwise we
4334 -- cannot fold Alignment.
4336 elsif Id = Attribute_Alignment then
4337 if Is_Entity_Name (P)
4338 and then Known_Alignment (Entity (P))
4340 Fold_Uint (N, Alignment (Entity (P)), False);
4348 -- No other attributes for objects are folded
4355 -- Cases where P is not an object. Cannot do anything if P is
4356 -- not the name of an entity.
4358 elsif not Is_Entity_Name (P) then
4362 -- Otherwise get prefix entity
4365 P_Entity := Entity (P);
4368 -- At this stage P_Entity is the entity to which the attribute
4369 -- is to be applied. This is usually simply the entity of the
4370 -- prefix, except in some cases of attributes for objects, where
4371 -- as described above, we apply the attribute to the object type.
4373 -- First foldable possibility is a scalar or array type (RM 4.9(7))
4374 -- that is not generic (generic types are eliminated by RM 4.9(25)).
4375 -- Note we allow non-static non-generic types at this stage as further
4378 if Is_Type (P_Entity)
4379 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
4380 and then (not Is_Generic_Type (P_Entity))
4384 -- Second foldable possibility is an array object (RM 4.9(8))
4386 elsif (Ekind (P_Entity) = E_Variable
4388 Ekind (P_Entity) = E_Constant)
4389 and then Is_Array_Type (Etype (P_Entity))
4390 and then (not Is_Generic_Type (Etype (P_Entity)))
4392 P_Type := Etype (P_Entity);
4394 -- If the entity is an array constant with an unconstrained
4395 -- nominal subtype then get the type from the initial value.
4396 -- If the value has been expanded into assignments, the expression
4397 -- is not present and the attribute reference remains dynamic.
4398 -- We could do better here and retrieve the type ???
4400 if Ekind (P_Entity) = E_Constant
4401 and then not Is_Constrained (P_Type)
4403 if No (Constant_Value (P_Entity)) then
4406 P_Type := Etype (Constant_Value (P_Entity));
4410 -- Definite must be folded if the prefix is not a generic type,
4411 -- that is to say if we are within an instantiation. Same processing
4412 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
4413 -- and Unconstrained_Array.
4415 elsif (Id = Attribute_Definite
4417 Id = Attribute_Has_Discriminants
4419 Id = Attribute_Type_Class
4421 Id = Attribute_Unconstrained_Array)
4422 and then not Is_Generic_Type (P_Entity)
4426 -- We can fold 'Size applied to a type if the size is known
4427 -- (as happens for a size from an attribute definition clause).
4428 -- At this stage, this can happen only for types (e.g. record
4429 -- types) for which the size is always non-static. We exclude
4430 -- generic types from consideration (since they have bogus
4431 -- sizes set within templates).
4433 elsif Id = Attribute_Size
4434 and then Is_Type (P_Entity)
4435 and then (not Is_Generic_Type (P_Entity))
4436 and then Known_Static_RM_Size (P_Entity)
4438 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
4441 -- We can fold 'Alignment applied to a type if the alignment is known
4442 -- (as happens for an alignment from an attribute definition clause).
4443 -- At this stage, this can happen only for types (e.g. record
4444 -- types) for which the size is always non-static. We exclude
4445 -- generic types from consideration (since they have bogus
4446 -- sizes set within templates).
4448 elsif Id = Attribute_Alignment
4449 and then Is_Type (P_Entity)
4450 and then (not Is_Generic_Type (P_Entity))
4451 and then Known_Alignment (P_Entity)
4453 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
4456 -- No other cases are foldable (they certainly aren't static, and at
4457 -- the moment we don't try to fold any cases other than these three).
4464 -- If either attribute or the prefix is Any_Type, then propagate
4465 -- Any_Type to the result and don't do anything else at all.
4467 if P_Type = Any_Type
4468 or else (Present (E1) and then Etype (E1) = Any_Type)
4469 or else (Present (E2) and then Etype (E2) = Any_Type)
4471 Set_Etype (N, Any_Type);
4475 -- Scalar subtype case. We have not yet enforced the static requirement
4476 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
4477 -- of non-static attribute references (e.g. S'Digits for a non-static
4478 -- floating-point type, which we can compute at compile time).
4480 -- Note: this folding of non-static attributes is not simply a case of
4481 -- optimization. For many of the attributes affected, Gigi cannot handle
4482 -- the attribute and depends on the front end having folded them away.
4484 -- Note: although we don't require staticness at this stage, we do set
4485 -- the Static variable to record the staticness, for easy reference by
4486 -- those attributes where it matters (e.g. Succ and Pred), and also to
4487 -- be used to ensure that non-static folded things are not marked as
4488 -- being static (a check that is done right at the end).
4490 P_Root_Type := Root_Type (P_Type);
4491 P_Base_Type := Base_Type (P_Type);
4493 -- If the root type or base type is generic, then we cannot fold. This
4494 -- test is needed because subtypes of generic types are not always
4495 -- marked as being generic themselves (which seems odd???)
4497 if Is_Generic_Type (P_Root_Type)
4498 or else Is_Generic_Type (P_Base_Type)
4503 if Is_Scalar_Type (P_Type) then
4504 Static := Is_OK_Static_Subtype (P_Type);
4506 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
4507 -- since we can't do anything with unconstrained arrays. In addition,
4508 -- only the First, Last and Length attributes are possibly static.
4509 -- In addition Component_Size is possibly foldable, even though it
4510 -- can never be static.
4512 -- Definite, Has_Discriminants, Type_Class and Unconstrained_Array are
4513 -- again exceptions, because they apply as well to unconstrained types.
4515 elsif Id = Attribute_Definite
4517 Id = Attribute_Has_Discriminants
4519 Id = Attribute_Type_Class
4521 Id = Attribute_Unconstrained_Array
4526 if not Is_Constrained (P_Type)
4527 or else (Id /= Attribute_Component_Size and then
4528 Id /= Attribute_First and then
4529 Id /= Attribute_Last and then
4530 Id /= Attribute_Length)
4536 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
4537 -- scalar case, we hold off on enforcing staticness, since there are
4538 -- cases which we can fold at compile time even though they are not
4539 -- static (e.g. 'Length applied to a static index, even though other
4540 -- non-static indexes make the array type non-static). This is only
4541 -- an optimization, but it falls out essentially free, so why not.
4542 -- Again we compute the variable Static for easy reference later
4543 -- (note that no array attributes are static in Ada 83).
4551 N := First_Index (P_Type);
4552 while Present (N) loop
4553 Static := Static and then Is_Static_Subtype (Etype (N));
4555 -- If however the index type is generic, attributes cannot
4558 if Is_Generic_Type (Etype (N))
4559 and then Id /= Attribute_Component_Size
4569 -- Check any expressions that are present. Note that these expressions,
4570 -- depending on the particular attribute type, are either part of the
4571 -- attribute designator, or they are arguments in a case where the
4572 -- attribute reference returns a function. In the latter case, the
4573 -- rule in (RM 4.9(22)) applies and in particular requires the type
4574 -- of the expressions to be scalar in order for the attribute to be
4575 -- considered to be static.
4582 while Present (E) loop
4584 -- If expression is not static, then the attribute reference
4585 -- result certainly cannot be static.
4587 if not Is_Static_Expression (E) then
4591 -- If the result is not known at compile time, or is not of
4592 -- a scalar type, then the result is definitely not static,
4593 -- so we can quit now.
4595 if not Compile_Time_Known_Value (E)
4596 or else not Is_Scalar_Type (Etype (E))
4598 -- An odd special case, if this is a Pos attribute, this
4599 -- is where we need to apply a range check since it does
4600 -- not get done anywhere else.
4602 if Id = Attribute_Pos then
4603 if Is_Integer_Type (Etype (E)) then
4604 Apply_Range_Check (E, Etype (N));
4611 -- If the expression raises a constraint error, then so does
4612 -- the attribute reference. We keep going in this case because
4613 -- we are still interested in whether the attribute reference
4614 -- is static even if it is not static.
4616 elsif Raises_Constraint_Error (E) then
4617 Set_Raises_Constraint_Error (N);
4623 if Raises_Constraint_Error (Prefix (N)) then
4628 -- Deal with the case of a static attribute reference that raises
4629 -- constraint error. The Raises_Constraint_Error flag will already
4630 -- have been set, and the Static flag shows whether the attribute
4631 -- reference is static. In any case we certainly can't fold such an
4632 -- attribute reference.
4634 -- Note that the rewriting of the attribute node with the constraint
4635 -- error node is essential in this case, because otherwise Gigi might
4636 -- blow up on one of the attributes it never expects to see.
4638 -- The constraint_error node must have the type imposed by the context,
4639 -- to avoid spurious errors in the enclosing expression.
4641 if Raises_Constraint_Error (N) then
4643 Make_Raise_Constraint_Error (Sloc (N),
4644 Reason => CE_Range_Check_Failed);
4645 Set_Etype (CE_Node, Etype (N));
4646 Set_Raises_Constraint_Error (CE_Node);
4648 Rewrite (N, Relocate_Node (CE_Node));
4649 Set_Is_Static_Expression (N, Static);
4653 -- At this point we have a potentially foldable attribute reference.
4654 -- If Static is set, then the attribute reference definitely obeys
4655 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
4656 -- folded. If Static is not set, then the attribute may or may not
4657 -- be foldable, and the individual attribute processing routines
4658 -- test Static as required in cases where it makes a difference.
4660 -- In the case where Static is not set, we do know that all the
4661 -- expressions present are at least known at compile time (we
4662 -- assumed above that if this was not the case, then there was
4663 -- no hope of static evaluation). However, we did not require
4664 -- that the bounds of the prefix type be compile time known,
4665 -- let alone static). That's because there are many attributes
4666 -- that can be computed at compile time on non-static subtypes,
4667 -- even though such references are not static expressions.
4675 when Attribute_Adjacent =>
4678 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
4684 when Attribute_Aft =>
4685 Fold_Uint (N, UI_From_Int (Aft_Value), True);
4691 when Attribute_Alignment => Alignment_Block : declare
4692 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
4695 -- Fold if alignment is set and not otherwise
4697 if Known_Alignment (P_TypeA) then
4698 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
4700 end Alignment_Block;
4706 -- Can only be folded in No_Ast_Handler case
4708 when Attribute_AST_Entry =>
4709 if not Is_AST_Entry (P_Entity) then
4711 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
4720 -- Bit can never be folded
4722 when Attribute_Bit =>
4729 -- Body_version can never be static
4731 when Attribute_Body_Version =>
4738 when Attribute_Ceiling =>
4740 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
4742 --------------------
4743 -- Component_Size --
4744 --------------------
4746 when Attribute_Component_Size =>
4747 if Known_Static_Component_Size (P_Type) then
4748 Fold_Uint (N, Component_Size (P_Type), False);
4755 when Attribute_Compose =>
4758 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
4765 -- Constrained is never folded for now, there may be cases that
4766 -- could be handled at compile time. to be looked at later.
4768 when Attribute_Constrained =>
4775 when Attribute_Copy_Sign =>
4778 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
4784 when Attribute_Delta =>
4785 Fold_Ureal (N, Delta_Value (P_Type), True);
4791 when Attribute_Definite =>
4796 if Is_Indefinite_Subtype (P_Entity) then
4797 Result := New_Occurrence_Of (Standard_False, Loc);
4799 Result := New_Occurrence_Of (Standard_True, Loc);
4802 Rewrite (N, Result);
4803 Analyze_And_Resolve (N, Standard_Boolean);
4810 when Attribute_Denorm =>
4812 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
4818 when Attribute_Digits =>
4819 Fold_Uint (N, Digits_Value (P_Type), True);
4825 when Attribute_Emax =>
4827 -- Ada 83 attribute is defined as (RM83 3.5.8)
4829 -- T'Emax = 4 * T'Mantissa
4831 Fold_Uint (N, 4 * Mantissa, True);
4837 when Attribute_Enum_Rep =>
4839 -- For an enumeration type with a non-standard representation
4840 -- use the Enumeration_Rep field of the proper constant. Note
4841 -- that this would not work for types Character/Wide_Character,
4842 -- since no real entities are created for the enumeration
4843 -- literals, but that does not matter since these two types
4844 -- do not have non-standard representations anyway.
4846 if Is_Enumeration_Type (P_Type)
4847 and then Has_Non_Standard_Rep (P_Type)
4849 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
4851 -- For enumeration types with standard representations and all
4852 -- other cases (i.e. all integer and modular types), Enum_Rep
4853 -- is equivalent to Pos.
4856 Fold_Uint (N, Expr_Value (E1), Static);
4863 when Attribute_Epsilon =>
4865 -- Ada 83 attribute is defined as (RM83 3.5.8)
4867 -- T'Epsilon = 2.0**(1 - T'Mantissa)
4869 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
4875 when Attribute_Exponent =>
4877 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
4883 when Attribute_First => First_Attr :
4887 if Compile_Time_Known_Value (Lo_Bound) then
4888 if Is_Real_Type (P_Type) then
4889 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
4891 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
4900 when Attribute_Fixed_Value =>
4907 when Attribute_Floor =>
4909 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
4915 when Attribute_Fore =>
4916 if Compile_Time_Known_Bounds (P_Type) then
4917 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
4924 when Attribute_Fraction =>
4926 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
4928 -----------------------
4929 -- Has_Discriminants --
4930 -----------------------
4932 when Attribute_Has_Discriminants =>
4937 if Has_Discriminants (P_Entity) then
4938 Result := New_Occurrence_Of (Standard_True, Loc);
4940 Result := New_Occurrence_Of (Standard_False, Loc);
4943 Rewrite (N, Result);
4944 Analyze_And_Resolve (N, Standard_Boolean);
4951 when Attribute_Identity =>
4958 -- Image is a scalar attribute, but is never static, because it is
4959 -- not a static function (having a non-scalar argument (RM 4.9(22))
4961 when Attribute_Image =>
4968 -- Img is a scalar attribute, but is never static, because it is
4969 -- not a static function (having a non-scalar argument (RM 4.9(22))
4971 when Attribute_Img =>
4978 when Attribute_Integer_Value =>
4985 when Attribute_Large =>
4987 -- For fixed-point, we use the identity:
4989 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
4991 if Is_Fixed_Point_Type (P_Type) then
4993 Make_Op_Multiply (Loc,
4995 Make_Op_Subtract (Loc,
4999 Make_Real_Literal (Loc, Ureal_2),
5001 Make_Attribute_Reference (Loc,
5003 Attribute_Name => Name_Mantissa)),
5004 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
5007 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
5009 Analyze_And_Resolve (N, C_Type);
5011 -- Floating-point (Ada 83 compatibility)
5014 -- Ada 83 attribute is defined as (RM83 3.5.8)
5016 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
5020 -- T'Emax = 4 * T'Mantissa
5023 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
5031 when Attribute_Last => Last :
5035 if Compile_Time_Known_Value (Hi_Bound) then
5036 if Is_Real_Type (P_Type) then
5037 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
5039 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
5048 when Attribute_Leading_Part =>
5050 Eval_Fat.Leading_Part
5051 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
5057 when Attribute_Length => Length : declare
5061 -- In the case of a generic index type, the bounds may
5062 -- appear static but the computation is not meaningful,
5063 -- and may generate a spurious warning.
5065 Ind := First_Index (P_Type);
5067 while Present (Ind) loop
5068 if Is_Generic_Type (Etype (Ind)) then
5077 if Compile_Time_Known_Value (Lo_Bound)
5078 and then Compile_Time_Known_Value (Hi_Bound)
5081 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
5090 when Attribute_Machine =>
5093 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
5100 when Attribute_Machine_Emax =>
5101 Float_Attribute_Universal_Integer (
5109 AAMPL_Machine_Emax);
5115 when Attribute_Machine_Emin =>
5116 Float_Attribute_Universal_Integer (
5124 AAMPL_Machine_Emin);
5126 ----------------------
5127 -- Machine_Mantissa --
5128 ----------------------
5130 when Attribute_Machine_Mantissa =>
5131 Float_Attribute_Universal_Integer (
5132 IEEES_Machine_Mantissa,
5133 IEEEL_Machine_Mantissa,
5134 IEEEX_Machine_Mantissa,
5135 VAXFF_Machine_Mantissa,
5136 VAXDF_Machine_Mantissa,
5137 VAXGF_Machine_Mantissa,
5138 AAMPS_Machine_Mantissa,
5139 AAMPL_Machine_Mantissa);
5141 -----------------------
5142 -- Machine_Overflows --
5143 -----------------------
5145 when Attribute_Machine_Overflows =>
5147 -- Always true for fixed-point
5149 if Is_Fixed_Point_Type (P_Type) then
5150 Fold_Uint (N, True_Value, True);
5152 -- Floating point case
5156 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
5164 when Attribute_Machine_Radix =>
5165 if Is_Fixed_Point_Type (P_Type) then
5166 if Is_Decimal_Fixed_Point_Type (P_Type)
5167 and then Machine_Radix_10 (P_Type)
5169 Fold_Uint (N, Uint_10, True);
5171 Fold_Uint (N, Uint_2, True);
5174 -- All floating-point type always have radix 2
5177 Fold_Uint (N, Uint_2, True);
5180 --------------------
5181 -- Machine_Rounds --
5182 --------------------
5184 when Attribute_Machine_Rounds =>
5186 -- Always False for fixed-point
5188 if Is_Fixed_Point_Type (P_Type) then
5189 Fold_Uint (N, False_Value, True);
5191 -- Else yield proper floating-point result
5195 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
5202 -- Note: Machine_Size is identical to Object_Size
5204 when Attribute_Machine_Size => Machine_Size : declare
5205 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5208 if Known_Esize (P_TypeA) then
5209 Fold_Uint (N, Esize (P_TypeA), True);
5217 when Attribute_Mantissa =>
5219 -- Fixed-point mantissa
5221 if Is_Fixed_Point_Type (P_Type) then
5223 -- Compile time foldable case
5225 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5227 Compile_Time_Known_Value (Type_High_Bound (P_Type))
5229 -- The calculation of the obsolete Ada 83 attribute Mantissa
5230 -- is annoying, because of AI00143, quoted here:
5232 -- !question 84-01-10
5234 -- Consider the model numbers for F:
5236 -- type F is delta 1.0 range -7.0 .. 8.0;
5238 -- The wording requires that F'MANTISSA be the SMALLEST
5239 -- integer number for which each bound of the specified
5240 -- range is either a model number or lies at most small
5241 -- distant from a model number. This means F'MANTISSA
5242 -- is required to be 3 since the range -7.0 .. 7.0 fits
5243 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
5244 -- number, namely, 7. Is this analysis correct? Note that
5245 -- this implies the upper bound of the range is not
5246 -- represented as a model number.
5248 -- !response 84-03-17
5250 -- The analysis is correct. The upper and lower bounds for
5251 -- a fixed point type can lie outside the range of model
5262 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
5263 UBound := Expr_Value_R (Type_High_Bound (P_Type));
5264 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
5265 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
5267 -- If the Bound is exactly a model number, i.e. a multiple
5268 -- of Small, then we back it off by one to get the integer
5269 -- value that must be representable.
5271 if Small_Value (P_Type) * Max_Man = Bound then
5272 Max_Man := Max_Man - 1;
5275 -- Now find corresponding size = Mantissa value
5278 while 2 ** Siz < Max_Man loop
5282 Fold_Uint (N, Siz, True);
5286 -- The case of dynamic bounds cannot be evaluated at compile
5287 -- time. Instead we use a runtime routine (see Exp_Attr).
5292 -- Floating-point Mantissa
5295 Fold_Uint (N, Mantissa, True);
5302 when Attribute_Max => Max :
5304 if Is_Real_Type (P_Type) then
5306 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5308 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
5312 ----------------------------------
5313 -- Max_Size_In_Storage_Elements --
5314 ----------------------------------
5316 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
5317 -- Storage_Unit boundary. We can fold any cases for which the size
5318 -- is known by the front end.
5320 when Attribute_Max_Size_In_Storage_Elements =>
5321 if Known_Esize (P_Type) then
5323 (Esize (P_Type) + System_Storage_Unit - 1) /
5324 System_Storage_Unit,
5328 --------------------
5329 -- Mechanism_Code --
5330 --------------------
5332 when Attribute_Mechanism_Code =>
5336 Mech : Mechanism_Type;
5340 Mech := Mechanism (P_Entity);
5343 Val := UI_To_Int (Expr_Value (E1));
5345 Formal := First_Formal (P_Entity);
5346 for J in 1 .. Val - 1 loop
5347 Next_Formal (Formal);
5349 Mech := Mechanism (Formal);
5353 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
5361 when Attribute_Min => Min :
5363 if Is_Real_Type (P_Type) then
5365 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5367 Fold_Uint (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
5375 when Attribute_Model =>
5377 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
5383 when Attribute_Model_Emin =>
5384 Float_Attribute_Universal_Integer (
5398 when Attribute_Model_Epsilon =>
5399 Float_Attribute_Universal_Real (
5400 IEEES_Model_Epsilon'Universal_Literal_String,
5401 IEEEL_Model_Epsilon'Universal_Literal_String,
5402 IEEEX_Model_Epsilon'Universal_Literal_String,
5403 VAXFF_Model_Epsilon'Universal_Literal_String,
5404 VAXDF_Model_Epsilon'Universal_Literal_String,
5405 VAXGF_Model_Epsilon'Universal_Literal_String,
5406 AAMPS_Model_Epsilon'Universal_Literal_String,
5407 AAMPL_Model_Epsilon'Universal_Literal_String);
5409 --------------------
5410 -- Model_Mantissa --
5411 --------------------
5413 when Attribute_Model_Mantissa =>
5414 Float_Attribute_Universal_Integer (
5415 IEEES_Model_Mantissa,
5416 IEEEL_Model_Mantissa,
5417 IEEEX_Model_Mantissa,
5418 VAXFF_Model_Mantissa,
5419 VAXDF_Model_Mantissa,
5420 VAXGF_Model_Mantissa,
5421 AAMPS_Model_Mantissa,
5422 AAMPL_Model_Mantissa);
5428 when Attribute_Model_Small =>
5429 Float_Attribute_Universal_Real (
5430 IEEES_Model_Small'Universal_Literal_String,
5431 IEEEL_Model_Small'Universal_Literal_String,
5432 IEEEX_Model_Small'Universal_Literal_String,
5433 VAXFF_Model_Small'Universal_Literal_String,
5434 VAXDF_Model_Small'Universal_Literal_String,
5435 VAXGF_Model_Small'Universal_Literal_String,
5436 AAMPS_Model_Small'Universal_Literal_String,
5437 AAMPL_Model_Small'Universal_Literal_String);
5443 when Attribute_Modulus =>
5444 Fold_Uint (N, Modulus (P_Type), True);
5446 --------------------
5447 -- Null_Parameter --
5448 --------------------
5450 -- Cannot fold, we know the value sort of, but the whole point is
5451 -- that there is no way to talk about this imaginary value except
5452 -- by using the attribute, so we leave it the way it is.
5454 when Attribute_Null_Parameter =>
5461 -- The Object_Size attribute for a type returns the Esize of the
5462 -- type and can be folded if this value is known.
5464 when Attribute_Object_Size => Object_Size : declare
5465 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5468 if Known_Esize (P_TypeA) then
5469 Fold_Uint (N, Esize (P_TypeA), True);
5473 -------------------------
5474 -- Passed_By_Reference --
5475 -------------------------
5477 -- Scalar types are never passed by reference
5479 when Attribute_Passed_By_Reference =>
5480 Fold_Uint (N, False_Value, True);
5486 when Attribute_Pos =>
5487 Fold_Uint (N, Expr_Value (E1), True);
5493 when Attribute_Pred => Pred :
5495 -- Floating-point case
5497 if Is_Floating_Point_Type (P_Type) then
5499 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
5503 elsif Is_Fixed_Point_Type (P_Type) then
5505 Expr_Value_R (E1) - Small_Value (P_Type), True);
5507 -- Modular integer case (wraps)
5509 elsif Is_Modular_Integer_Type (P_Type) then
5510 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
5512 -- Other scalar cases
5515 pragma Assert (Is_Scalar_Type (P_Type));
5517 if Is_Enumeration_Type (P_Type)
5518 and then Expr_Value (E1) =
5519 Expr_Value (Type_Low_Bound (P_Base_Type))
5521 Apply_Compile_Time_Constraint_Error
5522 (N, "Pred of `&''First`",
5523 CE_Overflow_Check_Failed,
5525 Warn => not Static);
5531 Fold_Uint (N, Expr_Value (E1) - 1, Static);
5539 -- No processing required, because by this stage, Range has been
5540 -- replaced by First .. Last, so this branch can never be taken.
5542 when Attribute_Range =>
5543 raise Program_Error;
5549 when Attribute_Range_Length =>
5552 if Compile_Time_Known_Value (Hi_Bound)
5553 and then Compile_Time_Known_Value (Lo_Bound)
5557 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
5565 when Attribute_Remainder =>
5568 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
5575 when Attribute_Round => Round :
5581 -- First we get the (exact result) in units of small
5583 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
5585 -- Now round that exactly to an integer
5587 Si := UR_To_Uint (Sr);
5589 -- Finally the result is obtained by converting back to real
5591 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
5598 when Attribute_Rounding =>
5600 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
5606 when Attribute_Safe_Emax =>
5607 Float_Attribute_Universal_Integer (
5621 when Attribute_Safe_First =>
5622 Float_Attribute_Universal_Real (
5623 IEEES_Safe_First'Universal_Literal_String,
5624 IEEEL_Safe_First'Universal_Literal_String,
5625 IEEEX_Safe_First'Universal_Literal_String,
5626 VAXFF_Safe_First'Universal_Literal_String,
5627 VAXDF_Safe_First'Universal_Literal_String,
5628 VAXGF_Safe_First'Universal_Literal_String,
5629 AAMPS_Safe_First'Universal_Literal_String,
5630 AAMPL_Safe_First'Universal_Literal_String);
5636 when Attribute_Safe_Large =>
5637 if Is_Fixed_Point_Type (P_Type) then
5639 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
5641 Float_Attribute_Universal_Real (
5642 IEEES_Safe_Large'Universal_Literal_String,
5643 IEEEL_Safe_Large'Universal_Literal_String,
5644 IEEEX_Safe_Large'Universal_Literal_String,
5645 VAXFF_Safe_Large'Universal_Literal_String,
5646 VAXDF_Safe_Large'Universal_Literal_String,
5647 VAXGF_Safe_Large'Universal_Literal_String,
5648 AAMPS_Safe_Large'Universal_Literal_String,
5649 AAMPL_Safe_Large'Universal_Literal_String);
5656 when Attribute_Safe_Last =>
5657 Float_Attribute_Universal_Real (
5658 IEEES_Safe_Last'Universal_Literal_String,
5659 IEEEL_Safe_Last'Universal_Literal_String,
5660 IEEEX_Safe_Last'Universal_Literal_String,
5661 VAXFF_Safe_Last'Universal_Literal_String,
5662 VAXDF_Safe_Last'Universal_Literal_String,
5663 VAXGF_Safe_Last'Universal_Literal_String,
5664 AAMPS_Safe_Last'Universal_Literal_String,
5665 AAMPL_Safe_Last'Universal_Literal_String);
5671 when Attribute_Safe_Small =>
5673 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
5674 -- for fixed-point, since is the same as Small, but we implement
5675 -- it for backwards compatibility.
5677 if Is_Fixed_Point_Type (P_Type) then
5678 Fold_Ureal (N, Small_Value (P_Type), Static);
5680 -- Ada 83 Safe_Small for floating-point cases
5683 Float_Attribute_Universal_Real (
5684 IEEES_Safe_Small'Universal_Literal_String,
5685 IEEEL_Safe_Small'Universal_Literal_String,
5686 IEEEX_Safe_Small'Universal_Literal_String,
5687 VAXFF_Safe_Small'Universal_Literal_String,
5688 VAXDF_Safe_Small'Universal_Literal_String,
5689 VAXGF_Safe_Small'Universal_Literal_String,
5690 AAMPS_Safe_Small'Universal_Literal_String,
5691 AAMPL_Safe_Small'Universal_Literal_String);
5698 when Attribute_Scale =>
5699 Fold_Uint (N, Scale_Value (P_Type), True);
5705 when Attribute_Scaling =>
5708 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
5714 when Attribute_Signed_Zeros =>
5716 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
5722 -- Size attribute returns the RM size. All scalar types can be folded,
5723 -- as well as any types for which the size is known by the front end,
5724 -- including any type for which a size attribute is specified.
5726 when Attribute_Size | Attribute_VADS_Size => Size : declare
5727 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5730 if RM_Size (P_TypeA) /= Uint_0 then
5734 if Id = Attribute_VADS_Size or else Use_VADS_Size then
5736 S : constant Node_Id := Size_Clause (P_TypeA);
5739 -- If a size clause applies, then use the size from it.
5740 -- This is one of the rare cases where we can use the
5741 -- Size_Clause field for a subtype when Has_Size_Clause
5742 -- is False. Consider:
5744 -- type x is range 1 .. 64; g
5745 -- for x'size use 12;
5746 -- subtype y is x range 0 .. 3;
5748 -- Here y has a size clause inherited from x, but normally
5749 -- it does not apply, and y'size is 2. However, y'VADS_Size
5750 -- is indeed 12 and not 2.
5753 and then Is_OK_Static_Expression (Expression (S))
5755 Fold_Uint (N, Expr_Value (Expression (S)), True);
5757 -- If no size is specified, then we simply use the object
5758 -- size in the VADS_Size case (e.g. Natural'Size is equal
5759 -- to Integer'Size, not one less).
5762 Fold_Uint (N, Esize (P_TypeA), True);
5766 -- Normal case (Size) in which case we want the RM_Size
5771 Static and then Is_Discrete_Type (P_TypeA));
5780 when Attribute_Small =>
5782 -- The floating-point case is present only for Ada 83 compatability.
5783 -- Note that strictly this is an illegal addition, since we are
5784 -- extending an Ada 95 defined attribute, but we anticipate an
5785 -- ARG ruling that will permit this.
5787 if Is_Floating_Point_Type (P_Type) then
5789 -- Ada 83 attribute is defined as (RM83 3.5.8)
5791 -- T'Small = 2.0**(-T'Emax - 1)
5795 -- T'Emax = 4 * T'Mantissa
5797 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
5799 -- Normal Ada 95 fixed-point case
5802 Fold_Ureal (N, Small_Value (P_Type), True);
5809 when Attribute_Succ => Succ :
5811 -- Floating-point case
5813 if Is_Floating_Point_Type (P_Type) then
5815 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
5819 elsif Is_Fixed_Point_Type (P_Type) then
5821 Expr_Value_R (E1) + Small_Value (P_Type), Static);
5823 -- Modular integer case (wraps)
5825 elsif Is_Modular_Integer_Type (P_Type) then
5826 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
5828 -- Other scalar cases
5831 pragma Assert (Is_Scalar_Type (P_Type));
5833 if Is_Enumeration_Type (P_Type)
5834 and then Expr_Value (E1) =
5835 Expr_Value (Type_High_Bound (P_Base_Type))
5837 Apply_Compile_Time_Constraint_Error
5838 (N, "Succ of `&''Last`",
5839 CE_Overflow_Check_Failed,
5841 Warn => not Static);
5846 Fold_Uint (N, Expr_Value (E1) + 1, Static);
5855 when Attribute_Truncation =>
5857 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
5863 when Attribute_Type_Class => Type_Class : declare
5864 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
5868 if Is_RTE (P_Root_Type, RE_Address) then
5869 Id := RE_Type_Class_Address;
5871 elsif Is_Enumeration_Type (Typ) then
5872 Id := RE_Type_Class_Enumeration;
5874 elsif Is_Integer_Type (Typ) then
5875 Id := RE_Type_Class_Integer;
5877 elsif Is_Fixed_Point_Type (Typ) then
5878 Id := RE_Type_Class_Fixed_Point;
5880 elsif Is_Floating_Point_Type (Typ) then
5881 Id := RE_Type_Class_Floating_Point;
5883 elsif Is_Array_Type (Typ) then
5884 Id := RE_Type_Class_Array;
5886 elsif Is_Record_Type (Typ) then
5887 Id := RE_Type_Class_Record;
5889 elsif Is_Access_Type (Typ) then
5890 Id := RE_Type_Class_Access;
5892 elsif Is_Enumeration_Type (Typ) then
5893 Id := RE_Type_Class_Enumeration;
5895 elsif Is_Task_Type (Typ) then
5896 Id := RE_Type_Class_Task;
5898 -- We treat protected types like task types. It would make more
5899 -- sense to have another enumeration value, but after all the
5900 -- whole point of this feature is to be exactly DEC compatible,
5901 -- and changing the type Type_Clas would not meet this requirement.
5903 elsif Is_Protected_Type (Typ) then
5904 Id := RE_Type_Class_Task;
5906 -- Not clear if there are any other possibilities, but if there
5907 -- are, then we will treat them as the address case.
5910 Id := RE_Type_Class_Address;
5913 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
5917 -----------------------
5918 -- Unbiased_Rounding --
5919 -----------------------
5921 when Attribute_Unbiased_Rounding =>
5923 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
5926 -------------------------
5927 -- Unconstrained_Array --
5928 -------------------------
5930 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
5931 Typ : constant Entity_Id := Underlying_Type (P_Type);
5934 if Is_Array_Type (P_Type)
5935 and then not Is_Constrained (Typ)
5937 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5939 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5942 -- Analyze and resolve as boolean, note that this attribute is
5943 -- a static attribute in GNAT.
5945 Analyze_And_Resolve (N, Standard_Boolean);
5947 end Unconstrained_Array;
5953 -- Processing is shared with Size
5959 when Attribute_Val => Val :
5961 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
5963 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
5965 Apply_Compile_Time_Constraint_Error
5966 (N, "Val expression out of range",
5967 CE_Range_Check_Failed,
5968 Warn => not Static);
5974 Fold_Uint (N, Expr_Value (E1), Static);
5982 -- The Value_Size attribute for a type returns the RM size of the
5983 -- type. This an always be folded for scalar types, and can also
5984 -- be folded for non-scalar types if the size is set.
5986 when Attribute_Value_Size => Value_Size : declare
5987 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5990 if RM_Size (P_TypeA) /= Uint_0 then
5991 Fold_Uint (N, RM_Size (P_TypeA), True);
6000 -- Version can never be static
6002 when Attribute_Version =>
6009 -- Wide_Image is a scalar attribute, but is never static, because it
6010 -- is not a static function (having a non-scalar argument (RM 4.9(22))
6012 when Attribute_Wide_Image =>
6019 -- Processing for Wide_Width is combined with Width
6025 -- This processing also handles the case of Wide_Width
6027 when Attribute_Width | Attribute_Wide_Width => Width :
6029 if Compile_Time_Known_Bounds (P_Type) then
6031 -- Floating-point types
6033 if Is_Floating_Point_Type (P_Type) then
6035 -- Width is zero for a null range (RM 3.5 (38))
6037 if Expr_Value_R (Type_High_Bound (P_Type)) <
6038 Expr_Value_R (Type_Low_Bound (P_Type))
6040 Fold_Uint (N, Uint_0, True);
6043 -- For floating-point, we have +N.dddE+nnn where length
6044 -- of ddd is determined by type'Digits - 1, but is one
6045 -- if Digits is one (RM 3.5 (33)).
6047 -- nnn is set to 2 for Short_Float and Float (32 bit
6048 -- floats), and 3 for Long_Float and Long_Long_Float.
6049 -- This is not quite right, but is good enough.
6053 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
6056 if Esize (P_Type) <= 32 then
6062 Fold_Uint (N, UI_From_Int (Len), True);
6066 -- Fixed-point types
6068 elsif Is_Fixed_Point_Type (P_Type) then
6070 -- Width is zero for a null range (RM 3.5 (38))
6072 if Expr_Value (Type_High_Bound (P_Type)) <
6073 Expr_Value (Type_Low_Bound (P_Type))
6075 Fold_Uint (N, Uint_0, True);
6077 -- The non-null case depends on the specific real type
6080 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
6083 (N, UI_From_Int (Fore_Value + 1 + Aft_Value), True);
6090 R : constant Entity_Id := Root_Type (P_Type);
6091 Lo : constant Uint :=
6092 Expr_Value (Type_Low_Bound (P_Type));
6093 Hi : constant Uint :=
6094 Expr_Value (Type_High_Bound (P_Type));
6107 -- Width for types derived from Standard.Character
6108 -- and Standard.Wide_Character.
6110 elsif R = Standard_Character
6111 or else R = Standard_Wide_Character
6115 -- Set W larger if needed
6117 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
6119 -- Assume all wide-character escape sequences are
6120 -- same length, so we can quit when we reach one.
6123 if Id = Attribute_Wide_Width then
6124 W := Int'Max (W, 3);
6127 W := Int'Max (W, Length_Wide);
6132 C := Character'Val (J);
6134 -- Test for all cases where Character'Image
6135 -- yields an image that is longer than three
6136 -- characters. First the cases of Reserved_xxx
6137 -- names (length = 12).
6140 when Reserved_128 | Reserved_129 |
6141 Reserved_132 | Reserved_153
6145 when BS | HT | LF | VT | FF | CR |
6146 SO | SI | EM | FS | GS | RS |
6147 US | RI | MW | ST | PM
6151 when NUL | SOH | STX | ETX | EOT |
6152 ENQ | ACK | BEL | DLE | DC1 |
6153 DC2 | DC3 | DC4 | NAK | SYN |
6154 ETB | CAN | SUB | ESC | DEL |
6155 BPH | NBH | NEL | SSA | ESA |
6156 HTS | HTJ | VTS | PLD | PLU |
6157 SS2 | SS3 | DCS | PU1 | PU2 |
6158 STS | CCH | SPA | EPA | SOS |
6159 SCI | CSI | OSC | APC
6163 when Space .. Tilde |
6164 No_Break_Space .. LC_Y_Diaeresis
6169 W := Int'Max (W, Wt);
6173 -- Width for types derived from Standard.Boolean
6175 elsif R = Standard_Boolean then
6182 -- Width for integer types
6184 elsif Is_Integer_Type (P_Type) then
6185 T := UI_Max (abs Lo, abs Hi);
6193 -- Only remaining possibility is user declared enum type
6196 pragma Assert (Is_Enumeration_Type (P_Type));
6199 L := First_Literal (P_Type);
6201 while Present (L) loop
6203 -- Only pay attention to in range characters
6205 if Lo <= Enumeration_Pos (L)
6206 and then Enumeration_Pos (L) <= Hi
6208 -- For Width case, use decoded name
6210 if Id = Attribute_Width then
6211 Get_Decoded_Name_String (Chars (L));
6212 Wt := Nat (Name_Len);
6214 -- For Wide_Width, use encoded name, and then
6215 -- adjust for the encoding.
6218 Get_Name_String (Chars (L));
6220 -- Character literals are always of length 3
6222 if Name_Buffer (1) = 'Q' then
6225 -- Otherwise loop to adjust for upper/wide chars
6228 Wt := Nat (Name_Len);
6230 for J in 1 .. Name_Len loop
6231 if Name_Buffer (J) = 'U' then
6233 elsif Name_Buffer (J) = 'W' then
6240 W := Int'Max (W, Wt);
6247 Fold_Uint (N, UI_From_Int (W), True);
6253 -- The following attributes can never be folded, and furthermore we
6254 -- should not even have entered the case statement for any of these.
6255 -- Note that in some cases, the values have already been folded as
6256 -- a result of the processing in Analyze_Attribute.
6258 when Attribute_Abort_Signal |
6261 Attribute_Address_Size |
6262 Attribute_Asm_Input |
6263 Attribute_Asm_Output |
6265 Attribute_Bit_Order |
6266 Attribute_Bit_Position |
6267 Attribute_Callable |
6270 Attribute_Code_Address |
6272 Attribute_Default_Bit_Order |
6273 Attribute_Elaborated |
6274 Attribute_Elab_Body |
6275 Attribute_Elab_Spec |
6276 Attribute_External_Tag |
6277 Attribute_First_Bit |
6279 Attribute_Last_Bit |
6280 Attribute_Maximum_Alignment |
6282 Attribute_Partition_ID |
6283 Attribute_Pool_Address |
6284 Attribute_Position |
6286 Attribute_Storage_Pool |
6287 Attribute_Storage_Size |
6288 Attribute_Storage_Unit |
6290 Attribute_Target_Name |
6291 Attribute_Terminated |
6292 Attribute_To_Address |
6293 Attribute_UET_Address |
6294 Attribute_Unchecked_Access |
6295 Attribute_Universal_Literal_String |
6296 Attribute_Unrestricted_Access |
6299 Attribute_Wchar_T_Size |
6300 Attribute_Wide_Value |
6301 Attribute_Word_Size |
6304 raise Program_Error;
6308 -- At the end of the case, one more check. If we did a static evaluation
6309 -- so that the result is now a literal, then set Is_Static_Expression
6310 -- in the constant only if the prefix type is a static subtype. For
6311 -- non-static subtypes, the folding is still OK, but not static.
6313 -- An exception is the GNAT attribute Constrained_Array which is
6314 -- defined to be a static attribute in all cases.
6316 if Nkind (N) = N_Integer_Literal
6317 or else Nkind (N) = N_Real_Literal
6318 or else Nkind (N) = N_Character_Literal
6319 or else Nkind (N) = N_String_Literal
6320 or else (Is_Entity_Name (N)
6321 and then Ekind (Entity (N)) = E_Enumeration_Literal)
6323 Set_Is_Static_Expression (N, Static);
6325 -- If this is still an attribute reference, then it has not been folded
6326 -- and that means that its expressions are in a non-static context.
6328 elsif Nkind (N) = N_Attribute_Reference then
6331 -- Note: the else case not covered here are odd cases where the
6332 -- processing has transformed the attribute into something other
6333 -- than a constant. Nothing more to do in such cases.
6341 ------------------------------
6342 -- Is_Anonymous_Tagged_Base --
6343 ------------------------------
6345 function Is_Anonymous_Tagged_Base
6352 Anon = Current_Scope
6353 and then Is_Itype (Anon)
6354 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
6355 end Is_Anonymous_Tagged_Base;
6357 -----------------------
6358 -- Resolve_Attribute --
6359 -----------------------
6361 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
6362 Loc : constant Source_Ptr := Sloc (N);
6363 P : constant Node_Id := Prefix (N);
6364 Aname : constant Name_Id := Attribute_Name (N);
6365 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
6366 Btyp : constant Entity_Id := Base_Type (Typ);
6367 Index : Interp_Index;
6369 Nom_Subt : Entity_Id;
6372 -- If error during analysis, no point in continuing, except for
6373 -- array types, where we get better recovery by using unconstrained
6374 -- indices than nothing at all (see Check_Array_Type).
6377 and then Attr_Id /= Attribute_First
6378 and then Attr_Id /= Attribute_Last
6379 and then Attr_Id /= Attribute_Length
6380 and then Attr_Id /= Attribute_Range
6385 -- If attribute was universal type, reset to actual type
6387 if Etype (N) = Universal_Integer
6388 or else Etype (N) = Universal_Real
6393 -- Remaining processing depends on attribute
6401 -- For access attributes, if the prefix denotes an entity, it is
6402 -- interpreted as a name, never as a call. It may be overloaded,
6403 -- in which case resolution uses the profile of the context type.
6404 -- Otherwise prefix must be resolved.
6406 when Attribute_Access
6407 | Attribute_Unchecked_Access
6408 | Attribute_Unrestricted_Access =>
6410 if Is_Variable (P) then
6411 Note_Possible_Modification (P);
6414 if Is_Entity_Name (P) then
6415 if Is_Overloaded (P) then
6416 Get_First_Interp (P, Index, It);
6418 while Present (It.Nam) loop
6420 if Type_Conformant (Designated_Type (Typ), It.Nam) then
6421 Set_Entity (P, It.Nam);
6423 -- The prefix is definitely NOT overloaded anymore
6424 -- at this point, so we reset the Is_Overloaded
6425 -- flag to avoid any confusion when reanalyzing
6428 Set_Is_Overloaded (P, False);
6429 Generate_Reference (Entity (P), P);
6433 Get_Next_Interp (Index, It);
6436 -- If it is a subprogram name or a type, there is nothing
6439 elsif not Is_Overloadable (Entity (P))
6440 and then not Is_Type (Entity (P))
6445 Error_Msg_Name_1 := Aname;
6447 if not Is_Entity_Name (P) then
6450 elsif Is_Abstract (Entity (P))
6451 and then Is_Overloadable (Entity (P))
6453 Error_Msg_N ("prefix of % attribute cannot be abstract", P);
6454 Set_Etype (N, Any_Type);
6456 elsif Convention (Entity (P)) = Convention_Intrinsic then
6457 if Ekind (Entity (P)) = E_Enumeration_Literal then
6459 ("prefix of % attribute cannot be enumeration literal",
6463 ("prefix of % attribute cannot be intrinsic", P);
6466 Set_Etype (N, Any_Type);
6468 elsif Is_Thread_Body (Entity (P)) then
6470 ("prefix of % attribute cannot be a thread body", P);
6473 -- Assignments, return statements, components of aggregates,
6474 -- generic instantiations will require convention checks if
6475 -- the type is an access to subprogram. Given that there will
6476 -- also be accessibility checks on those, this is where the
6477 -- checks can eventually be centralized ???
6479 if Ekind (Btyp) = E_Access_Subprogram_Type then
6480 if Convention (Btyp) /= Convention (Entity (P)) then
6482 ("subprogram has invalid convention for context", P);
6485 Check_Subtype_Conformant
6486 (New_Id => Entity (P),
6487 Old_Id => Designated_Type (Btyp),
6491 if Attr_Id = Attribute_Unchecked_Access then
6492 Error_Msg_Name_1 := Aname;
6494 ("attribute% cannot be applied to a subprogram", P);
6496 elsif Aname = Name_Unrestricted_Access then
6497 null; -- Nothing to check
6499 -- Check the static accessibility rule of 3.10.2(32)
6501 elsif Attr_Id = Attribute_Access
6502 and then Subprogram_Access_Level (Entity (P))
6503 > Type_Access_Level (Btyp)
6505 if not In_Instance_Body then
6507 ("subprogram must not be deeper than access type",
6511 ("subprogram must not be deeper than access type?",
6514 ("Constraint_Error will be raised ?", P);
6515 Set_Raises_Constraint_Error (N);
6518 -- Check the restriction of 3.10.2(32) that disallows
6519 -- the type of the access attribute to be declared
6520 -- outside a generic body when the attribute occurs
6521 -- within that generic body.
6523 elsif Enclosing_Generic_Body (Entity (P))
6524 /= Enclosing_Generic_Body (Btyp)
6527 ("access type must not be outside generic body", P);
6531 -- if this is a renaming, an inherited operation, or a
6532 -- subprogram instance, use the original entity.
6534 if Is_Entity_Name (P)
6535 and then Is_Overloadable (Entity (P))
6536 and then Present (Alias (Entity (P)))
6539 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
6542 elsif Nkind (P) = N_Selected_Component
6543 and then Is_Overloadable (Entity (Selector_Name (P)))
6545 -- Protected operation. If operation is overloaded, must
6546 -- disambiguate. Prefix that denotes protected object itself
6547 -- is resolved with its own type.
6549 if Attr_Id = Attribute_Unchecked_Access then
6550 Error_Msg_Name_1 := Aname;
6552 ("attribute% cannot be applied to protected operation", P);
6555 Resolve (Prefix (P));
6556 Generate_Reference (Entity (Selector_Name (P)), P);
6558 elsif Is_Overloaded (P) then
6560 -- Use the designated type of the context to disambiguate.
6562 Index : Interp_Index;
6565 Get_First_Interp (P, Index, It);
6567 while Present (It.Typ) loop
6568 if Covers (Designated_Type (Typ), It.Typ) then
6569 Resolve (P, It.Typ);
6573 Get_Next_Interp (Index, It);
6580 -- X'Access is illegal if X denotes a constant and the access
6581 -- type is access-to-variable. Same for 'Unchecked_Access.
6582 -- The rule does not apply to 'Unrestricted_Access.
6584 if not (Ekind (Btyp) = E_Access_Subprogram_Type
6585 or else (Is_Record_Type (Btyp) and then
6586 Present (Corresponding_Remote_Type (Btyp)))
6587 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
6588 or else Is_Access_Constant (Btyp)
6589 or else Is_Variable (P)
6590 or else Attr_Id = Attribute_Unrestricted_Access)
6592 if Comes_From_Source (N) then
6593 Error_Msg_N ("access-to-variable designates constant", P);
6597 if (Attr_Id = Attribute_Access
6599 Attr_Id = Attribute_Unchecked_Access)
6600 and then (Ekind (Btyp) = E_General_Access_Type
6601 or else Ekind (Btyp) = E_Anonymous_Access_Type)
6603 if Is_Dependent_Component_Of_Mutable_Object (P) then
6605 ("illegal attribute for discriminant-dependent component",
6609 -- Check the static matching rule of 3.10.2(27). The
6610 -- nominal subtype of the prefix must statically
6611 -- match the designated type.
6613 Nom_Subt := Etype (P);
6615 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
6616 Nom_Subt := Etype (Nom_Subt);
6619 if Is_Tagged_Type (Designated_Type (Typ)) then
6621 -- If the attribute is in the context of an access
6622 -- parameter, then the prefix is allowed to be of
6623 -- the class-wide type (by AI-127).
6625 if Ekind (Typ) = E_Anonymous_Access_Type then
6626 if not Covers (Designated_Type (Typ), Nom_Subt)
6627 and then not Covers (Nom_Subt, Designated_Type (Typ))
6633 Desig := Designated_Type (Typ);
6635 if Is_Class_Wide_Type (Desig) then
6636 Desig := Etype (Desig);
6639 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
6644 ("type of prefix: & not compatible",
6647 ("\with &, the expected designated type",
6648 P, Designated_Type (Typ));
6653 elsif not Covers (Designated_Type (Typ), Nom_Subt)
6655 (not Is_Class_Wide_Type (Designated_Type (Typ))
6656 and then Is_Class_Wide_Type (Nom_Subt))
6659 ("type of prefix: & is not covered", P, Nom_Subt);
6661 ("\by &, the expected designated type" &
6662 " ('R'M 3.10.2 (27))", P, Designated_Type (Typ));
6665 if Is_Class_Wide_Type (Designated_Type (Typ))
6666 and then Has_Discriminants (Etype (Designated_Type (Typ)))
6667 and then Is_Constrained (Etype (Designated_Type (Typ)))
6668 and then Designated_Type (Typ) /= Nom_Subt
6670 Apply_Discriminant_Check
6671 (N, Etype (Designated_Type (Typ)));
6674 elsif not Subtypes_Statically_Match
6675 (Designated_Type (Base_Type (Typ)), Nom_Subt)
6677 not (Has_Discriminants (Designated_Type (Typ))
6680 (Designated_Type (Base_Type (Typ))))
6683 ("object subtype must statically match "
6684 & "designated subtype", P);
6686 if Is_Entity_Name (P)
6687 and then Is_Array_Type (Designated_Type (Typ))
6691 D : constant Node_Id := Declaration_Node (Entity (P));
6694 Error_Msg_N ("aliased object has explicit bounds?",
6696 Error_Msg_N ("\declare without bounds"
6697 & " (and with explicit initialization)?", D);
6698 Error_Msg_N ("\for use with unconstrained access?", D);
6703 -- Check the static accessibility rule of 3.10.2(28).
6704 -- Note that this check is not performed for the
6705 -- case of an anonymous access type, since the access
6706 -- attribute is always legal in such a context.
6708 if Attr_Id /= Attribute_Unchecked_Access
6709 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
6710 and then Ekind (Btyp) = E_General_Access_Type
6712 -- In an instance, this is a runtime check, but one we
6713 -- know will fail, so generate an appropriate warning.
6715 if In_Instance_Body then
6717 ("?non-local pointer cannot point to local object", P);
6719 ("?Program_Error will be raised at run time", P);
6721 Make_Raise_Program_Error (Loc,
6722 Reason => PE_Accessibility_Check_Failed));
6728 ("non-local pointer cannot point to local object", P);
6730 if Is_Record_Type (Current_Scope)
6731 and then (Nkind (Parent (N)) =
6732 N_Discriminant_Association
6734 Nkind (Parent (N)) =
6735 N_Index_Or_Discriminant_Constraint)
6738 Indic : Node_Id := Parent (Parent (N));
6741 while Present (Indic)
6742 and then Nkind (Indic) /= N_Subtype_Indication
6744 Indic := Parent (Indic);
6747 if Present (Indic) then
6749 ("\use an access definition for" &
6750 " the access discriminant of&", N,
6751 Entity (Subtype_Mark (Indic)));
6759 if Ekind (Btyp) = E_Access_Protected_Subprogram_Type
6760 and then Is_Entity_Name (P)
6761 and then not Is_Protected_Type (Scope (Entity (P)))
6763 Error_Msg_N ("context requires a protected subprogram", P);
6765 elsif Ekind (Btyp) = E_Access_Subprogram_Type
6766 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
6768 Error_Msg_N ("context requires a non-protected subprogram", P);
6771 -- The context cannot be a pool-specific type, but this is a
6772 -- legality rule, not a resolution rule, so it must be checked
6773 -- separately, after possibly disambiguation (see AI-245).
6775 if Ekind (Btyp) = E_Access_Type
6776 and then Attr_Id /= Attribute_Unrestricted_Access
6778 Wrong_Type (N, Typ);
6783 -- Check for incorrect atomic/volatile reference (RM C.6(12))
6785 if Attr_Id /= Attribute_Unrestricted_Access then
6786 if Is_Atomic_Object (P)
6787 and then not Is_Atomic (Designated_Type (Typ))
6790 ("access to atomic object cannot yield access-to-" &
6791 "non-atomic type", P);
6793 elsif Is_Volatile_Object (P)
6794 and then not Is_Volatile (Designated_Type (Typ))
6797 ("access to volatile object cannot yield access-to-" &
6798 "non-volatile type", P);
6806 -- Deal with resolving the type for Address attribute, overloading
6807 -- is not permitted here, since there is no context to resolve it.
6809 when Attribute_Address | Attribute_Code_Address =>
6811 -- To be safe, assume that if the address of a variable is taken,
6812 -- it may be modified via this address, so note modification.
6814 if Is_Variable (P) then
6815 Note_Possible_Modification (P);
6818 if Nkind (P) in N_Subexpr
6819 and then Is_Overloaded (P)
6821 Get_First_Interp (P, Index, It);
6822 Get_Next_Interp (Index, It);
6824 if Present (It.Nam) then
6825 Error_Msg_Name_1 := Aname;
6827 ("prefix of % attribute cannot be overloaded", N);
6832 if not Is_Entity_Name (P)
6833 or else not Is_Overloadable (Entity (P))
6835 if not Is_Task_Type (Etype (P))
6836 or else Nkind (P) = N_Explicit_Dereference
6842 -- If this is the name of a derived subprogram, or that of a
6843 -- generic actual, the address is that of the original entity.
6845 if Is_Entity_Name (P)
6846 and then Is_Overloadable (Entity (P))
6847 and then Present (Alias (Entity (P)))
6850 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
6857 -- Prefix of the AST_Entry attribute is an entry name which must
6858 -- not be resolved, since this is definitely not an entry call.
6860 when Attribute_AST_Entry =>
6867 -- Prefix of Body_Version attribute can be a subprogram name which
6868 -- must not be resolved, since this is not a call.
6870 when Attribute_Body_Version =>
6877 -- Prefix of Caller attribute is an entry name which must not
6878 -- be resolved, since this is definitely not an entry call.
6880 when Attribute_Caller =>
6887 -- Shares processing with Address attribute
6893 -- If the prefix of the Count attribute is an entry name it must not
6894 -- be resolved, since this is definitely not an entry call. However,
6895 -- if it is an element of an entry family, the index itself may
6896 -- have to be resolved because it can be a general expression.
6898 when Attribute_Count =>
6899 if Nkind (P) = N_Indexed_Component
6900 and then Is_Entity_Name (Prefix (P))
6903 Indx : constant Node_Id := First (Expressions (P));
6904 Fam : constant Entity_Id := Entity (Prefix (P));
6906 Resolve (Indx, Entry_Index_Type (Fam));
6907 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
6915 -- Prefix of the Elaborated attribute is a subprogram name which
6916 -- must not be resolved, since this is definitely not a call. Note
6917 -- that it is a library unit, so it cannot be overloaded here.
6919 when Attribute_Elaborated =>
6922 --------------------
6923 -- Mechanism_Code --
6924 --------------------
6926 -- Prefix of the Mechanism_Code attribute is a function name
6927 -- which must not be resolved. Should we check for overloaded ???
6929 when Attribute_Mechanism_Code =>
6936 -- Most processing is done in sem_dist, after determining the
6937 -- context type. Node is rewritten as a conversion to a runtime call.
6939 when Attribute_Partition_ID =>
6940 Process_Partition_Id (N);
6943 when Attribute_Pool_Address =>
6950 -- We replace the Range attribute node with a range expression
6951 -- whose bounds are the 'First and 'Last attributes applied to the
6952 -- same prefix. The reason that we do this transformation here
6953 -- instead of in the expander is that it simplifies other parts of
6954 -- the semantic analysis which assume that the Range has been
6955 -- replaced; thus it must be done even when in semantic-only mode
6956 -- (note that the RM specifically mentions this equivalence, we
6957 -- take care that the prefix is only evaluated once).
6959 when Attribute_Range => Range_Attribute :
6964 function Check_Discriminated_Prival
6967 -- The range of a private component constrained by a
6968 -- discriminant is rewritten to make the discriminant
6969 -- explicit. This solves some complex visibility problems
6970 -- related to the use of privals.
6972 --------------------------------
6973 -- Check_Discriminated_Prival --
6974 --------------------------------
6976 function Check_Discriminated_Prival
6981 if Is_Entity_Name (N)
6982 and then Ekind (Entity (N)) = E_In_Parameter
6983 and then not Within_Init_Proc
6985 return Make_Identifier (Sloc (N), Chars (Entity (N)));
6987 return Duplicate_Subexpr (N);
6989 end Check_Discriminated_Prival;
6991 -- Start of processing for Range_Attribute
6994 if not Is_Entity_Name (P)
6995 or else not Is_Type (Entity (P))
7000 -- Check whether prefix is (renaming of) private component
7001 -- of protected type.
7003 if Is_Entity_Name (P)
7004 and then Comes_From_Source (N)
7005 and then Is_Array_Type (Etype (P))
7006 and then Number_Dimensions (Etype (P)) = 1
7007 and then (Ekind (Scope (Entity (P))) = E_Protected_Type
7009 Ekind (Scope (Scope (Entity (P)))) =
7013 Check_Discriminated_Prival
7014 (Type_Low_Bound (Etype (First_Index (Etype (P)))));
7017 Check_Discriminated_Prival
7018 (Type_High_Bound (Etype (First_Index (Etype (P)))));
7022 Make_Attribute_Reference (Loc,
7023 Prefix => Duplicate_Subexpr (P),
7024 Attribute_Name => Name_Last,
7025 Expressions => Expressions (N));
7028 Make_Attribute_Reference (Loc,
7030 Attribute_Name => Name_First,
7031 Expressions => Expressions (N));
7034 -- If the original was marked as Must_Not_Freeze (see code
7035 -- in Sem_Ch3.Make_Index), then make sure the rewriting
7036 -- does not freeze either.
7038 if Must_Not_Freeze (N) then
7039 Set_Must_Not_Freeze (HB);
7040 Set_Must_Not_Freeze (LB);
7041 Set_Must_Not_Freeze (Prefix (HB));
7042 Set_Must_Not_Freeze (Prefix (LB));
7045 if Raises_Constraint_Error (Prefix (N)) then
7047 -- Preserve Sloc of prefix in the new bounds, so that
7048 -- the posted warning can be removed if we are within
7049 -- unreachable code.
7051 Set_Sloc (LB, Sloc (Prefix (N)));
7052 Set_Sloc (HB, Sloc (Prefix (N)));
7055 Rewrite (N, Make_Range (Loc, LB, HB));
7056 Analyze_And_Resolve (N, Typ);
7058 -- Normally after resolving attribute nodes, Eval_Attribute
7059 -- is called to do any possible static evaluation of the node.
7060 -- However, here since the Range attribute has just been
7061 -- transformed into a range expression it is no longer an
7062 -- attribute node and therefore the call needs to be avoided
7063 -- and is accomplished by simply returning from the procedure.
7066 end Range_Attribute;
7072 -- Prefix must not be resolved in this case, since it is not a
7073 -- real entity reference. No action of any kind is require!
7075 when Attribute_UET_Address =>
7078 ----------------------
7079 -- Unchecked_Access --
7080 ----------------------
7082 -- Processing is shared with Access
7084 -------------------------
7085 -- Unrestricted_Access --
7086 -------------------------
7088 -- Processing is shared with Access
7094 -- Apply range check. Note that we did not do this during the
7095 -- analysis phase, since we wanted Eval_Attribute to have a
7096 -- chance at finding an illegal out of range value.
7098 when Attribute_Val =>
7100 -- Note that we do our own Eval_Attribute call here rather than
7101 -- use the common one, because we need to do processing after
7102 -- the call, as per above comment.
7106 -- Eval_Attribute may replace the node with a raise CE, or
7107 -- fold it to a constant. Obviously we only apply a scalar
7108 -- range check if this did not happen!
7110 if Nkind (N) = N_Attribute_Reference
7111 and then Attribute_Name (N) = Name_Val
7113 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
7122 -- Prefix of Version attribute can be a subprogram name which
7123 -- must not be resolved, since this is not a call.
7125 when Attribute_Version =>
7128 ----------------------
7129 -- Other Attributes --
7130 ----------------------
7132 -- For other attributes, resolve prefix unless it is a type. If
7133 -- the attribute reference itself is a type name ('Base and 'Class)
7134 -- then this is only legal within a task or protected record.
7137 if not Is_Entity_Name (P)
7138 or else not Is_Type (Entity (P))
7143 -- If the attribute reference itself is a type name ('Base,
7144 -- 'Class) then this is only legal within a task or protected
7145 -- record. What is this all about ???
7147 if Is_Entity_Name (N)
7148 and then Is_Type (Entity (N))
7150 if Is_Concurrent_Type (Entity (N))
7151 and then In_Open_Scopes (Entity (P))
7156 ("invalid use of subtype name in expression or call", N);
7160 -- For attributes whose argument may be a string, complete
7161 -- resolution of argument now. This avoids premature expansion
7162 -- (and the creation of transient scopes) before the attribute
7163 -- reference is resolved.
7166 when Attribute_Value =>
7167 Resolve (First (Expressions (N)), Standard_String);
7169 when Attribute_Wide_Value =>
7170 Resolve (First (Expressions (N)), Standard_Wide_String);
7172 when others => null;
7176 -- Normally the Freezing is done by Resolve but sometimes the Prefix
7177 -- is not resolved, in which case the freezing must be done now.
7179 Freeze_Expression (P);
7181 -- Finally perform static evaluation on the attribute reference
7185 end Resolve_Attribute;