1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
29 with Atree; use Atree;
30 with Checks; use Checks;
31 with Einfo; use Einfo;
32 with Errout; use Errout;
34 with Exp_Tss; use Exp_Tss;
35 with Exp_Util; use Exp_Util;
36 with Expander; use Expander;
37 with Freeze; use Freeze;
39 with Lib.Xref; use Lib.Xref;
40 with Namet; use Namet;
41 with Nlists; use Nlists;
42 with Nmake; use Nmake;
44 with Restrict; use Restrict;
45 with Rident; use Rident;
46 with Rtsfind; use Rtsfind;
47 with Sdefault; use Sdefault;
49 with Sem_Cat; use Sem_Cat;
50 with Sem_Ch6; use Sem_Ch6;
51 with Sem_Ch8; use Sem_Ch8;
52 with Sem_Dist; use Sem_Dist;
53 with Sem_Eval; use Sem_Eval;
54 with Sem_Res; use Sem_Res;
55 with Sem_Type; use Sem_Type;
56 with Sem_Util; use Sem_Util;
57 with Stand; use Stand;
58 with Sinfo; use Sinfo;
59 with Sinput; use Sinput;
60 with Snames; use Snames;
62 with Stringt; use Stringt;
63 with Targparm; use Targparm;
64 with Ttypes; use Ttypes;
65 with Ttypef; use Ttypef;
66 with Tbuild; use Tbuild;
67 with Uintp; use Uintp;
68 with Urealp; use Urealp;
69 with Widechar; use Widechar;
71 package body Sem_Attr is
73 True_Value : constant Uint := Uint_1;
74 False_Value : constant Uint := Uint_0;
75 -- Synonyms to be used when these constants are used as Boolean values
77 Bad_Attribute : exception;
78 -- Exception raised if an error is detected during attribute processing,
79 -- used so that we can abandon the processing so we don't run into
80 -- trouble with cascaded errors.
82 -- The following array is the list of attributes defined in the Ada 83 RM
84 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
90 Attribute_Constrained |
103 Attribute_Leading_Part |
105 Attribute_Machine_Emax |
106 Attribute_Machine_Emin |
107 Attribute_Machine_Mantissa |
108 Attribute_Machine_Overflows |
109 Attribute_Machine_Radix |
110 Attribute_Machine_Rounds |
116 Attribute_Safe_Emax |
117 Attribute_Safe_Large |
118 Attribute_Safe_Small |
121 Attribute_Storage_Size |
123 Attribute_Terminated |
126 Attribute_Width => True,
129 -----------------------
130 -- Local_Subprograms --
131 -----------------------
133 procedure Eval_Attribute (N : Node_Id);
134 -- Performs compile time evaluation of attributes where possible, leaving
135 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
136 -- set, and replacing the node with a literal node if the value can be
137 -- computed at compile time. All static attribute references are folded,
138 -- as well as a number of cases of non-static attributes that can always
139 -- be computed at compile time (e.g. floating-point model attributes that
140 -- are applied to non-static subtypes). Of course in such cases, the
141 -- Is_Static_Expression flag will not be set on the resulting literal.
142 -- Note that the only required action of this procedure is to catch the
143 -- static expression cases as described in the RM. Folding of other cases
144 -- is done where convenient, but some additional non-static folding is in
145 -- N_Expand_Attribute_Reference in cases where this is more convenient.
147 function Is_Anonymous_Tagged_Base
151 -- For derived tagged types that constrain parent discriminants we build
152 -- an anonymous unconstrained base type. We need to recognize the relation
153 -- between the two when analyzing an access attribute for a constrained
154 -- component, before the full declaration for Typ has been analyzed, and
155 -- where therefore the prefix of the attribute does not match the enclosing
158 -----------------------
159 -- Analyze_Attribute --
160 -----------------------
162 procedure Analyze_Attribute (N : Node_Id) is
163 Loc : constant Source_Ptr := Sloc (N);
164 Aname : constant Name_Id := Attribute_Name (N);
165 P : constant Node_Id := Prefix (N);
166 Exprs : constant List_Id := Expressions (N);
167 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
172 -- Type of prefix after analysis
174 P_Base_Type : Entity_Id;
175 -- Base type of prefix after analysis
177 -----------------------
178 -- Local Subprograms --
179 -----------------------
181 procedure Analyze_Access_Attribute;
182 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
183 -- Internally, Id distinguishes which of the three cases is involved.
185 procedure Check_Array_Or_Scalar_Type;
186 -- Common procedure used by First, Last, Range attribute to check
187 -- that the prefix is a constrained array or scalar type, or a name
188 -- of an array object, and that an argument appears only if appropriate
189 -- (i.e. only in the array case).
191 procedure Check_Array_Type;
192 -- Common semantic checks for all array attributes. Checks that the
193 -- prefix is a constrained array type or the name of an array object.
194 -- The error message for non-arrays is specialized appropriately.
196 procedure Check_Asm_Attribute;
197 -- Common semantic checks for Asm_Input and Asm_Output attributes
199 procedure Check_Component;
200 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
201 -- Position. Checks prefix is an appropriate selected component.
203 procedure Check_Decimal_Fixed_Point_Type;
204 -- Check that prefix of attribute N is a decimal fixed-point type
206 procedure Check_Dereference;
207 -- If the prefix of attribute is an object of an access type, then
208 -- introduce an explicit deference, and adjust P_Type accordingly.
210 procedure Check_Discrete_Type;
211 -- Verify that prefix of attribute N is a discrete type
214 -- Check that no attribute arguments are present
216 procedure Check_Either_E0_Or_E1;
217 -- Check that there are zero or one attribute arguments present
220 -- Check that exactly one attribute argument is present
223 -- Check that two attribute arguments are present
225 procedure Check_Enum_Image;
226 -- If the prefix type is an enumeration type, set all its literals
227 -- as referenced, since the image function could possibly end up
228 -- referencing any of the literals indirectly.
230 procedure Check_Fixed_Point_Type;
231 -- Verify that prefix of attribute N is a fixed type
233 procedure Check_Fixed_Point_Type_0;
234 -- Verify that prefix of attribute N is a fixed type and that
235 -- no attribute expressions are present
237 procedure Check_Floating_Point_Type;
238 -- Verify that prefix of attribute N is a float type
240 procedure Check_Floating_Point_Type_0;
241 -- Verify that prefix of attribute N is a float type and that
242 -- no attribute expressions are present
244 procedure Check_Floating_Point_Type_1;
245 -- Verify that prefix of attribute N is a float type and that
246 -- exactly one attribute expression is present
248 procedure Check_Floating_Point_Type_2;
249 -- Verify that prefix of attribute N is a float type and that
250 -- two attribute expressions are present
252 procedure Legal_Formal_Attribute;
253 -- Common processing for attributes Definite, Has_Access_Values,
254 -- and Has_Discriminants
256 procedure Check_Integer_Type;
257 -- Verify that prefix of attribute N is an integer type
259 procedure Check_Library_Unit;
260 -- Verify that prefix of attribute N is a library unit
262 procedure Check_Not_Incomplete_Type;
263 -- Check that P (the prefix of the attribute) is not an incomplete
264 -- type or a private type for which no full view has been given.
266 procedure Check_Object_Reference (P : Node_Id);
267 -- Check that P (the prefix of the attribute) is an object reference
269 procedure Check_Program_Unit;
270 -- Verify that prefix of attribute N is a program unit
272 procedure Check_Real_Type;
273 -- Verify that prefix of attribute N is fixed or float type
275 procedure Check_Scalar_Type;
276 -- Verify that prefix of attribute N is a scalar type
278 procedure Check_Standard_Prefix;
279 -- Verify that prefix of attribute N is package Standard
281 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
282 -- Validity checking for stream attribute. Nam is the TSS name of the
283 -- corresponding possible defined attribute function (e.g. for the
284 -- Read attribute, Nam will be TSS_Stream_Read).
286 procedure Check_Task_Prefix;
287 -- Verify that prefix of attribute N is a task or task type
289 procedure Check_Type;
290 -- Verify that the prefix of attribute N is a type
292 procedure Check_Unit_Name (Nod : Node_Id);
293 -- Check that Nod is of the form of a library unit name, i.e that
294 -- it is an identifier, or a selected component whose prefix is
295 -- itself of the form of a library unit name. Note that this is
296 -- quite different from Check_Program_Unit, since it only checks
297 -- the syntactic form of the name, not the semantic identity. This
298 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
299 -- UET_Address) which can refer to non-visible unit.
301 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
302 pragma No_Return (Error_Attr);
303 procedure Error_Attr;
304 pragma No_Return (Error_Attr);
305 -- Posts error using Error_Msg_N at given node, sets type of attribute
306 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
307 -- semantic processing. The message typically contains a % insertion
308 -- character which is replaced by the attribute name. The call with
309 -- no arguments is used when the caller has already generated the
310 -- required error messages.
312 procedure Standard_Attribute (Val : Int);
313 -- Used to process attributes whose prefix is package Standard which
314 -- yield values of type Universal_Integer. The attribute reference
315 -- node is rewritten with an integer literal of the given value.
317 procedure Unexpected_Argument (En : Node_Id);
318 -- Signal unexpected attribute argument (En is the argument)
320 procedure Validate_Non_Static_Attribute_Function_Call;
321 -- Called when processing an attribute that is a function call to a
322 -- non-static function, i.e. an attribute function that either takes
323 -- non-scalar arguments or returns a non-scalar result. Verifies that
324 -- such a call does not appear in a preelaborable context.
326 ------------------------------
327 -- Analyze_Access_Attribute --
328 ------------------------------
330 procedure Analyze_Access_Attribute is
331 Acc_Type : Entity_Id;
336 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
337 -- Build an access-to-object type whose designated type is DT,
338 -- and whose Ekind is appropriate to the attribute type. The
339 -- type that is constructed is returned as the result.
341 procedure Build_Access_Subprogram_Type (P : Node_Id);
342 -- Build an access to subprogram whose designated type is
343 -- the type of the prefix. If prefix is overloaded, so it the
344 -- node itself. The result is stored in Acc_Type.
346 ------------------------------
347 -- Build_Access_Object_Type --
348 ------------------------------
350 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
354 if Aname = Name_Unrestricted_Access then
357 (E_Allocator_Type, Current_Scope, Loc, 'A');
361 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
364 Set_Etype (Typ, Typ);
365 Init_Size_Align (Typ);
367 Set_Associated_Node_For_Itype (Typ, N);
368 Set_Directly_Designated_Type (Typ, DT);
370 end Build_Access_Object_Type;
372 ----------------------------------
373 -- Build_Access_Subprogram_Type --
374 ----------------------------------
376 procedure Build_Access_Subprogram_Type (P : Node_Id) is
377 Index : Interp_Index;
380 function Get_Kind (E : Entity_Id) return Entity_Kind;
381 -- Distinguish between access to regular and protected
388 function Get_Kind (E : Entity_Id) return Entity_Kind is
390 if Convention (E) = Convention_Protected then
391 return E_Access_Protected_Subprogram_Type;
393 return E_Access_Subprogram_Type;
397 -- Start of processing for Build_Access_Subprogram_Type
400 -- In the case of an access to subprogram, use the name of the
401 -- subprogram itself as the designated type. Type-checking in
402 -- this case compares the signatures of the designated types.
404 if not Is_Overloaded (P) then
407 (Get_Kind (Entity (P)), Current_Scope, Loc, 'A');
408 Set_Etype (Acc_Type, Acc_Type);
409 Set_Directly_Designated_Type (Acc_Type, Entity (P));
410 Set_Etype (N, Acc_Type);
413 Get_First_Interp (P, Index, It);
414 Set_Etype (N, Any_Type);
416 while Present (It.Nam) loop
417 if not Is_Intrinsic_Subprogram (It.Nam) then
420 (Get_Kind (It.Nam), Current_Scope, Loc, 'A');
421 Set_Etype (Acc_Type, Acc_Type);
422 Set_Directly_Designated_Type (Acc_Type, It.Nam);
423 Add_One_Interp (N, Acc_Type, Acc_Type);
426 Get_Next_Interp (Index, It);
429 if Etype (N) = Any_Type then
430 Error_Attr ("prefix of % attribute cannot be intrinsic", P);
433 end Build_Access_Subprogram_Type;
435 -- Start of processing for Analyze_Access_Attribute
440 if Nkind (P) = N_Character_Literal then
442 ("prefix of % attribute cannot be enumeration literal", P);
445 -- Case of access to subprogram
447 if Is_Entity_Name (P)
448 and then Is_Overloadable (Entity (P))
450 -- Not allowed for nested subprograms if No_Implicit_Dynamic_Code
451 -- restriction set (since in general a trampoline is required).
453 if not Is_Library_Level_Entity (Entity (P)) then
454 Check_Restriction (No_Implicit_Dynamic_Code, P);
457 -- Build the appropriate subprogram type
459 Build_Access_Subprogram_Type (P);
461 -- For unrestricted access, kill current values, since this
462 -- attribute allows a reference to a local subprogram that
463 -- could modify local variables to be passed out of scope
465 if Aname = Name_Unrestricted_Access then
471 -- Component is an operation of a protected type
473 elsif Nkind (P) = N_Selected_Component
474 and then Is_Overloadable (Entity (Selector_Name (P)))
476 if Ekind (Entity (Selector_Name (P))) = E_Entry then
477 Error_Attr ("prefix of % attribute must be subprogram", P);
480 Build_Access_Subprogram_Type (Selector_Name (P));
484 -- Deal with incorrect reference to a type, but note that some
485 -- accesses are allowed (references to the current type instance).
487 if Is_Entity_Name (P) then
488 Scop := Current_Scope;
491 if Is_Type (Typ) then
493 -- OK if we are within the scope of a limited type
494 -- let's mark the component as having per object constraint
496 if Is_Anonymous_Tagged_Base (Scop, Typ) then
504 Q : Node_Id := Parent (N);
508 and then Nkind (Q) /= N_Component_Declaration
513 Set_Has_Per_Object_Constraint (
514 Defining_Identifier (Q), True);
518 if Nkind (P) = N_Expanded_Name then
520 ("current instance prefix must be a direct name", P);
523 -- If a current instance attribute appears within a
524 -- a component constraint it must appear alone; other
525 -- contexts (default expressions, within a task body)
526 -- are not subject to this restriction.
528 if not In_Default_Expression
529 and then not Has_Completion (Scop)
531 Nkind (Parent (N)) /= N_Discriminant_Association
533 Nkind (Parent (N)) /= N_Index_Or_Discriminant_Constraint
536 ("current instance attribute must appear alone", N);
539 -- OK if we are in initialization procedure for the type
540 -- in question, in which case the reference to the type
541 -- is rewritten as a reference to the current object.
543 elsif Ekind (Scop) = E_Procedure
544 and then Is_Init_Proc (Scop)
545 and then Etype (First_Formal (Scop)) = Typ
548 Make_Attribute_Reference (Loc,
549 Prefix => Make_Identifier (Loc, Name_uInit),
550 Attribute_Name => Name_Unrestricted_Access));
554 -- OK if a task type, this test needs sharpening up ???
556 elsif Is_Task_Type (Typ) then
559 -- Otherwise we have an error case
562 Error_Attr ("% attribute cannot be applied to type", P);
568 -- If we fall through, we have a normal access to object case.
569 -- Unrestricted_Access is legal wherever an allocator would be
570 -- legal, so its Etype is set to E_Allocator. The expected type
571 -- of the other attributes is a general access type, and therefore
572 -- we label them with E_Access_Attribute_Type.
574 if not Is_Overloaded (P) then
575 Acc_Type := Build_Access_Object_Type (P_Type);
576 Set_Etype (N, Acc_Type);
579 Index : Interp_Index;
583 Set_Etype (N, Any_Type);
584 Get_First_Interp (P, Index, It);
586 while Present (It.Typ) loop
587 Acc_Type := Build_Access_Object_Type (It.Typ);
588 Add_One_Interp (N, Acc_Type, Acc_Type);
589 Get_Next_Interp (Index, It);
594 -- If we have an access to an object, and the attribute comes
595 -- from source, then set the object as potentially source modified.
596 -- We do this because the resulting access pointer can be used to
597 -- modify the variable, and we might not detect this, leading to
598 -- some junk warnings.
600 if Is_Entity_Name (P) then
601 Set_Never_Set_In_Source (Entity (P), False);
604 -- Check for aliased view unless unrestricted case. We allow
605 -- a nonaliased prefix when within an instance because the
606 -- prefix may have been a tagged formal object, which is
607 -- defined to be aliased even when the actual might not be
608 -- (other instance cases will have been caught in the generic).
609 -- Similarly, within an inlined body we know that the attribute
610 -- is legal in the original subprogram, and therefore legal in
613 if Aname /= Name_Unrestricted_Access
614 and then not Is_Aliased_View (P)
615 and then not In_Instance
616 and then not In_Inlined_Body
618 Error_Attr ("prefix of % attribute must be aliased", P);
620 end Analyze_Access_Attribute;
622 --------------------------------
623 -- Check_Array_Or_Scalar_Type --
624 --------------------------------
626 procedure Check_Array_Or_Scalar_Type is
630 -- Dimension number for array attributes.
633 -- Case of string literal or string literal subtype. These cases
634 -- cannot arise from legal Ada code, but the expander is allowed
635 -- to generate them. They require special handling because string
636 -- literal subtypes do not have standard bounds (the whole idea
637 -- of these subtypes is to avoid having to generate the bounds)
639 if Ekind (P_Type) = E_String_Literal_Subtype then
640 Set_Etype (N, Etype (First_Index (P_Base_Type)));
645 elsif Is_Scalar_Type (P_Type) then
649 Error_Attr ("invalid argument in % attribute", E1);
651 Set_Etype (N, P_Base_Type);
655 -- The following is a special test to allow 'First to apply to
656 -- private scalar types if the attribute comes from generated
657 -- code. This occurs in the case of Normalize_Scalars code.
659 elsif Is_Private_Type (P_Type)
660 and then Present (Full_View (P_Type))
661 and then Is_Scalar_Type (Full_View (P_Type))
662 and then not Comes_From_Source (N)
664 Set_Etype (N, Implementation_Base_Type (P_Type));
666 -- Array types other than string literal subtypes handled above
671 -- We know prefix is an array type, or the name of an array
672 -- object, and that the expression, if present, is static
673 -- and within the range of the dimensions of the type.
675 pragma Assert (Is_Array_Type (P_Type));
676 Index := First_Index (P_Base_Type);
680 -- First dimension assumed
682 Set_Etype (N, Base_Type (Etype (Index)));
685 D := UI_To_Int (Intval (E1));
687 for J in 1 .. D - 1 loop
691 Set_Etype (N, Base_Type (Etype (Index)));
692 Set_Etype (E1, Standard_Integer);
695 end Check_Array_Or_Scalar_Type;
697 ----------------------
698 -- Check_Array_Type --
699 ----------------------
701 procedure Check_Array_Type is
703 -- Dimension number for array attributes.
706 -- If the type is a string literal type, then this must be generated
707 -- internally, and no further check is required on its legality.
709 if Ekind (P_Type) = E_String_Literal_Subtype then
712 -- If the type is a composite, it is an illegal aggregate, no point
715 elsif P_Type = Any_Composite then
719 -- Normal case of array type or subtype
721 Check_Either_E0_Or_E1;
724 if Is_Array_Type (P_Type) then
725 if not Is_Constrained (P_Type)
726 and then Is_Entity_Name (P)
727 and then Is_Type (Entity (P))
729 -- Note: we do not call Error_Attr here, since we prefer to
730 -- continue, using the relevant index type of the array,
731 -- even though it is unconstrained. This gives better error
732 -- recovery behavior.
734 Error_Msg_Name_1 := Aname;
736 ("prefix for % attribute must be constrained array", P);
739 D := Number_Dimensions (P_Type);
742 if Is_Private_Type (P_Type) then
744 ("prefix for % attribute may not be private type", P);
746 elsif Is_Access_Type (P_Type)
747 and then Is_Array_Type (Designated_Type (P_Type))
748 and then Is_Entity_Name (P)
749 and then Is_Type (Entity (P))
751 Error_Attr ("prefix of % attribute cannot be access type", P);
753 elsif Attr_Id = Attribute_First
755 Attr_Id = Attribute_Last
757 Error_Attr ("invalid prefix for % attribute", P);
760 Error_Attr ("prefix for % attribute must be array", P);
765 Resolve (E1, Any_Integer);
766 Set_Etype (E1, Standard_Integer);
768 if not Is_Static_Expression (E1)
769 or else Raises_Constraint_Error (E1)
772 ("expression for dimension must be static!", E1);
775 elsif UI_To_Int (Expr_Value (E1)) > D
776 or else UI_To_Int (Expr_Value (E1)) < 1
778 Error_Attr ("invalid dimension number for array type", E1);
781 end Check_Array_Type;
783 -------------------------
784 -- Check_Asm_Attribute --
785 -------------------------
787 procedure Check_Asm_Attribute is
792 -- Check first argument is static string expression
794 Analyze_And_Resolve (E1, Standard_String);
796 if Etype (E1) = Any_Type then
799 elsif not Is_OK_Static_Expression (E1) then
801 ("constraint argument must be static string expression!", E1);
805 -- Check second argument is right type
807 Analyze_And_Resolve (E2, Entity (P));
809 -- Note: that is all we need to do, we don't need to check
810 -- that it appears in a correct context. The Ada type system
811 -- will do that for us.
813 end Check_Asm_Attribute;
815 ---------------------
816 -- Check_Component --
817 ---------------------
819 procedure Check_Component is
823 if Nkind (P) /= N_Selected_Component
825 (Ekind (Entity (Selector_Name (P))) /= E_Component
827 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
830 ("prefix for % attribute must be selected component", P);
834 ------------------------------------
835 -- Check_Decimal_Fixed_Point_Type --
836 ------------------------------------
838 procedure Check_Decimal_Fixed_Point_Type is
842 if not Is_Decimal_Fixed_Point_Type (P_Type) then
844 ("prefix of % attribute must be decimal type", P);
846 end Check_Decimal_Fixed_Point_Type;
848 -----------------------
849 -- Check_Dereference --
850 -----------------------
852 procedure Check_Dereference is
855 -- Case of a subtype mark
857 if Is_Entity_Name (P)
858 and then Is_Type (Entity (P))
863 -- Case of an expression
867 if Is_Access_Type (P_Type) then
869 -- If there is an implicit dereference, then we must freeze
870 -- the designated type of the access type, since the type of
871 -- the referenced array is this type (see AI95-00106).
873 Freeze_Before (N, Designated_Type (P_Type));
876 Make_Explicit_Dereference (Sloc (P),
877 Prefix => Relocate_Node (P)));
879 Analyze_And_Resolve (P);
882 if P_Type = Any_Type then
886 P_Base_Type := Base_Type (P_Type);
888 end Check_Dereference;
890 -------------------------
891 -- Check_Discrete_Type --
892 -------------------------
894 procedure Check_Discrete_Type is
898 if not Is_Discrete_Type (P_Type) then
899 Error_Attr ("prefix of % attribute must be discrete type", P);
901 end Check_Discrete_Type;
907 procedure Check_E0 is
910 Unexpected_Argument (E1);
918 procedure Check_E1 is
920 Check_Either_E0_Or_E1;
924 -- Special-case attributes that are functions and that appear as
925 -- the prefix of another attribute. Error is posted on parent.
927 if Nkind (Parent (N)) = N_Attribute_Reference
928 and then (Attribute_Name (Parent (N)) = Name_Address
930 Attribute_Name (Parent (N)) = Name_Code_Address
932 Attribute_Name (Parent (N)) = Name_Access)
934 Error_Msg_Name_1 := Attribute_Name (Parent (N));
935 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
936 Set_Etype (Parent (N), Any_Type);
937 Set_Entity (Parent (N), Any_Type);
941 Error_Attr ("missing argument for % attribute", N);
950 procedure Check_E2 is
953 Error_Attr ("missing arguments for % attribute (2 required)", N);
955 Error_Attr ("missing argument for % attribute (2 required)", N);
959 ---------------------------
960 -- Check_Either_E0_Or_E1 --
961 ---------------------------
963 procedure Check_Either_E0_Or_E1 is
966 Unexpected_Argument (E2);
968 end Check_Either_E0_Or_E1;
970 ----------------------
971 -- Check_Enum_Image --
972 ----------------------
974 procedure Check_Enum_Image is
978 if Is_Enumeration_Type (P_Base_Type) then
979 Lit := First_Literal (P_Base_Type);
980 while Present (Lit) loop
981 Set_Referenced (Lit);
985 end Check_Enum_Image;
987 ----------------------------
988 -- Check_Fixed_Point_Type --
989 ----------------------------
991 procedure Check_Fixed_Point_Type is
995 if not Is_Fixed_Point_Type (P_Type) then
996 Error_Attr ("prefix of % attribute must be fixed point type", P);
998 end Check_Fixed_Point_Type;
1000 ------------------------------
1001 -- Check_Fixed_Point_Type_0 --
1002 ------------------------------
1004 procedure Check_Fixed_Point_Type_0 is
1006 Check_Fixed_Point_Type;
1008 end Check_Fixed_Point_Type_0;
1010 -------------------------------
1011 -- Check_Floating_Point_Type --
1012 -------------------------------
1014 procedure Check_Floating_Point_Type is
1018 if not Is_Floating_Point_Type (P_Type) then
1019 Error_Attr ("prefix of % attribute must be float type", P);
1021 end Check_Floating_Point_Type;
1023 ---------------------------------
1024 -- Check_Floating_Point_Type_0 --
1025 ---------------------------------
1027 procedure Check_Floating_Point_Type_0 is
1029 Check_Floating_Point_Type;
1031 end Check_Floating_Point_Type_0;
1033 ---------------------------------
1034 -- Check_Floating_Point_Type_1 --
1035 ---------------------------------
1037 procedure Check_Floating_Point_Type_1 is
1039 Check_Floating_Point_Type;
1041 end Check_Floating_Point_Type_1;
1043 ---------------------------------
1044 -- Check_Floating_Point_Type_2 --
1045 ---------------------------------
1047 procedure Check_Floating_Point_Type_2 is
1049 Check_Floating_Point_Type;
1051 end Check_Floating_Point_Type_2;
1053 ------------------------
1054 -- Check_Integer_Type --
1055 ------------------------
1057 procedure Check_Integer_Type is
1061 if not Is_Integer_Type (P_Type) then
1062 Error_Attr ("prefix of % attribute must be integer type", P);
1064 end Check_Integer_Type;
1066 ------------------------
1067 -- Check_Library_Unit --
1068 ------------------------
1070 procedure Check_Library_Unit is
1072 if not Is_Compilation_Unit (Entity (P)) then
1073 Error_Attr ("prefix of % attribute must be library unit", P);
1075 end Check_Library_Unit;
1077 -------------------------------
1078 -- Check_Not_Incomplete_Type --
1079 -------------------------------
1081 procedure Check_Not_Incomplete_Type is
1083 if not Is_Entity_Name (P)
1084 or else not Is_Type (Entity (P))
1085 or else In_Default_Expression
1090 Check_Fully_Declared (P_Type, P);
1092 end Check_Not_Incomplete_Type;
1094 ----------------------------
1095 -- Check_Object_Reference --
1096 ----------------------------
1098 procedure Check_Object_Reference (P : Node_Id) is
1102 -- If we need an object, and we have a prefix that is the name of
1103 -- a function entity, convert it into a function call.
1105 if Is_Entity_Name (P)
1106 and then Ekind (Entity (P)) = E_Function
1108 Rtyp := Etype (Entity (P));
1111 Make_Function_Call (Sloc (P),
1112 Name => Relocate_Node (P)));
1114 Analyze_And_Resolve (P, Rtyp);
1116 -- Otherwise we must have an object reference
1118 elsif not Is_Object_Reference (P) then
1119 Error_Attr ("prefix of % attribute must be object", P);
1121 end Check_Object_Reference;
1123 ------------------------
1124 -- Check_Program_Unit --
1125 ------------------------
1127 procedure Check_Program_Unit is
1129 if Is_Entity_Name (P) then
1131 K : constant Entity_Kind := Ekind (Entity (P));
1132 T : constant Entity_Id := Etype (Entity (P));
1135 if K in Subprogram_Kind
1136 or else K in Task_Kind
1137 or else K in Protected_Kind
1138 or else K = E_Package
1139 or else K in Generic_Unit_Kind
1140 or else (K = E_Variable
1144 Is_Protected_Type (T)))
1151 Error_Attr ("prefix of % attribute must be program unit", P);
1152 end Check_Program_Unit;
1154 ---------------------
1155 -- Check_Real_Type --
1156 ---------------------
1158 procedure Check_Real_Type is
1162 if not Is_Real_Type (P_Type) then
1163 Error_Attr ("prefix of % attribute must be real type", P);
1165 end Check_Real_Type;
1167 -----------------------
1168 -- Check_Scalar_Type --
1169 -----------------------
1171 procedure Check_Scalar_Type is
1175 if not Is_Scalar_Type (P_Type) then
1176 Error_Attr ("prefix of % attribute must be scalar type", P);
1178 end Check_Scalar_Type;
1180 ---------------------------
1181 -- Check_Standard_Prefix --
1182 ---------------------------
1184 procedure Check_Standard_Prefix is
1188 if Nkind (P) /= N_Identifier
1189 or else Chars (P) /= Name_Standard
1191 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1194 end Check_Standard_Prefix;
1196 ----------------------------
1197 -- Check_Stream_Attribute --
1198 ----------------------------
1200 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1205 Validate_Non_Static_Attribute_Function_Call;
1207 -- With the exception of 'Input, Stream attributes are procedures,
1208 -- and can only appear at the position of procedure calls. We check
1209 -- for this here, before they are rewritten, to give a more precise
1212 if Nam = TSS_Stream_Input then
1215 elsif Is_List_Member (N)
1216 and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
1217 and then Nkind (Parent (N)) /= N_Aggregate
1223 ("invalid context for attribute%, which is a procedure", N);
1227 Btyp := Implementation_Base_Type (P_Type);
1229 -- Stream attributes not allowed on limited types unless the
1230 -- special OK_For_Stream flag is set.
1232 if Is_Limited_Type (P_Type)
1233 and then Comes_From_Source (N)
1234 and then not Present (TSS (Btyp, Nam))
1235 and then No (Get_Rep_Pragma (Btyp, Name_Stream_Convert))
1237 Error_Msg_Name_1 := Aname;
1239 ("limited type& has no% attribute", P, Btyp);
1240 Explain_Limited_Type (P_Type, P);
1243 -- Check for violation of restriction No_Stream_Attributes
1245 if Is_RTE (P_Type, RE_Exception_Id)
1247 Is_RTE (P_Type, RE_Exception_Occurrence)
1249 Check_Restriction (No_Exception_Registration, P);
1252 -- Here we must check that the first argument is an access type
1253 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1255 Analyze_And_Resolve (E1);
1258 -- Note: the double call to Root_Type here is needed because the
1259 -- root type of a class-wide type is the corresponding type (e.g.
1260 -- X for X'Class, and we really want to go to the root.
1262 if not Is_Access_Type (Etyp)
1263 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1264 RTE (RE_Root_Stream_Type)
1267 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1270 -- Check that the second argument is of the right type if there is
1271 -- one (the Input attribute has only one argument so this is skipped)
1273 if Present (E2) then
1276 if Nam = TSS_Stream_Read
1277 and then not Is_OK_Variable_For_Out_Formal (E2)
1280 ("second argument of % attribute must be a variable", E2);
1283 Resolve (E2, P_Type);
1285 end Check_Stream_Attribute;
1287 -----------------------
1288 -- Check_Task_Prefix --
1289 -----------------------
1291 procedure Check_Task_Prefix is
1295 if Is_Task_Type (Etype (P))
1296 or else (Is_Access_Type (Etype (P))
1297 and then Is_Task_Type (Designated_Type (Etype (P))))
1301 Error_Attr ("prefix of % attribute must be a task", P);
1303 end Check_Task_Prefix;
1309 -- The possibilities are an entity name denoting a type, or an
1310 -- attribute reference that denotes a type (Base or Class). If
1311 -- the type is incomplete, replace it with its full view.
1313 procedure Check_Type is
1315 if not Is_Entity_Name (P)
1316 or else not Is_Type (Entity (P))
1318 Error_Attr ("prefix of % attribute must be a type", P);
1320 elsif Ekind (Entity (P)) = E_Incomplete_Type
1321 and then Present (Full_View (Entity (P)))
1323 P_Type := Full_View (Entity (P));
1324 Set_Entity (P, P_Type);
1328 ---------------------
1329 -- Check_Unit_Name --
1330 ---------------------
1332 procedure Check_Unit_Name (Nod : Node_Id) is
1334 if Nkind (Nod) = N_Identifier then
1337 elsif Nkind (Nod) = N_Selected_Component then
1338 Check_Unit_Name (Prefix (Nod));
1340 if Nkind (Selector_Name (Nod)) = N_Identifier then
1345 Error_Attr ("argument for % attribute must be unit name", P);
1346 end Check_Unit_Name;
1352 procedure Error_Attr is
1354 Set_Etype (N, Any_Type);
1355 Set_Entity (N, Any_Type);
1356 raise Bad_Attribute;
1359 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1361 Error_Msg_Name_1 := Aname;
1362 Error_Msg_N (Msg, Error_Node);
1366 ----------------------------
1367 -- Legal_Formal_Attribute --
1368 ----------------------------
1370 procedure Legal_Formal_Attribute is
1374 if not Is_Entity_Name (P)
1375 or else not Is_Type (Entity (P))
1377 Error_Attr ("prefix of % attribute must be generic type", N);
1379 elsif Is_Generic_Actual_Type (Entity (P))
1381 or else In_Inlined_Body
1385 elsif Is_Generic_Type (Entity (P)) then
1386 if not Is_Indefinite_Subtype (Entity (P)) then
1388 ("prefix of % attribute must be indefinite generic type", N);
1393 ("prefix of % attribute must be indefinite generic type", N);
1396 Set_Etype (N, Standard_Boolean);
1397 end Legal_Formal_Attribute;
1399 ------------------------
1400 -- Standard_Attribute --
1401 ------------------------
1403 procedure Standard_Attribute (Val : Int) is
1405 Check_Standard_Prefix;
1407 -- First a special check (more like a kludge really). For GNAT5
1408 -- on Windows, the alignments in GCC are severely mixed up. In
1409 -- particular, we have a situation where the maximum alignment
1410 -- that GCC thinks is possible is greater than the guaranteed
1411 -- alignment at run-time. That causes many problems. As a partial
1412 -- cure for this situation, we force a value of 4 for the maximum
1413 -- alignment attribute on this target. This still does not solve
1414 -- all problems, but it helps.
1416 -- A further (even more horrible) dimension to this kludge is now
1417 -- installed. There are two uses for Maximum_Alignment, one is to
1418 -- determine the maximum guaranteed alignment, that's the one we
1419 -- want the kludge to yield as 4. The other use is to maximally
1420 -- align objects, we can't use 4 here, since for example, long
1421 -- long integer has an alignment of 8, so we will get errors.
1423 -- It is of course impossible to determine which use the programmer
1424 -- has in mind, but an approximation for now is to disconnect the
1425 -- kludge if the attribute appears in an alignment clause.
1427 -- To be removed if GCC ever gets its act together here ???
1429 Alignment_Kludge : declare
1432 function On_X86 return Boolean;
1433 -- Determine if target is x86 (ia32), return True if so
1439 function On_X86 return Boolean is
1440 T : constant String := Sdefault.Target_Name.all;
1443 -- There is no clean way to check this. That's not surprising,
1444 -- the front end should not be doing this kind of test ???. The
1445 -- way we do it is test for either "86" or "pentium" being in
1446 -- the string for the target name.
1448 for J in T'First .. T'Last - 1 loop
1449 if T (J .. J + 1) = "86"
1450 or else (J <= T'Last - 6
1451 and then T (J .. J + 6) = "pentium")
1461 if Aname = Name_Maximum_Alignment and then On_X86 then
1464 while Nkind (P) in N_Subexpr loop
1468 if Nkind (P) /= N_Attribute_Definition_Clause
1469 or else Chars (P) /= Name_Alignment
1471 Rewrite (N, Make_Integer_Literal (Loc, 4));
1476 end Alignment_Kludge;
1478 -- Normally we get the value from gcc ???
1480 Rewrite (N, Make_Integer_Literal (Loc, Val));
1482 end Standard_Attribute;
1484 -------------------------
1485 -- Unexpected Argument --
1486 -------------------------
1488 procedure Unexpected_Argument (En : Node_Id) is
1490 Error_Attr ("unexpected argument for % attribute", En);
1491 end Unexpected_Argument;
1493 -------------------------------------------------
1494 -- Validate_Non_Static_Attribute_Function_Call --
1495 -------------------------------------------------
1497 -- This function should be moved to Sem_Dist ???
1499 procedure Validate_Non_Static_Attribute_Function_Call is
1501 if In_Preelaborated_Unit
1502 and then not In_Subprogram_Or_Concurrent_Unit
1504 Flag_Non_Static_Expr
1505 ("non-static function call in preelaborated unit!", N);
1507 end Validate_Non_Static_Attribute_Function_Call;
1509 -----------------------------------------------
1510 -- Start of Processing for Analyze_Attribute --
1511 -----------------------------------------------
1514 -- Immediate return if unrecognized attribute (already diagnosed
1515 -- by parser, so there is nothing more that we need to do)
1517 if not Is_Attribute_Name (Aname) then
1518 raise Bad_Attribute;
1521 -- Deal with Ada 83 and Features issues
1523 if Comes_From_Source (N) then
1524 if not Attribute_83 (Attr_Id) then
1525 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1526 Error_Msg_Name_1 := Aname;
1527 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1530 if Attribute_Impl_Def (Attr_Id) then
1531 Check_Restriction (No_Implementation_Attributes, N);
1536 -- Remote access to subprogram type access attribute reference needs
1537 -- unanalyzed copy for tree transformation. The analyzed copy is used
1538 -- for its semantic information (whether prefix is a remote subprogram
1539 -- name), the unanalyzed copy is used to construct new subtree rooted
1540 -- with N_aggregate which represents a fat pointer aggregate.
1542 if Aname = Name_Access then
1543 Discard_Node (Copy_Separate_Tree (N));
1546 -- Analyze prefix and exit if error in analysis. If the prefix is an
1547 -- incomplete type, use full view if available. A special case is
1548 -- that we never analyze the prefix of an Elab_Body or Elab_Spec
1549 -- or UET_Address attribute.
1551 if Aname /= Name_Elab_Body
1553 Aname /= Name_Elab_Spec
1555 Aname /= Name_UET_Address
1558 P_Type := Etype (P);
1560 if Is_Entity_Name (P)
1561 and then Present (Entity (P))
1562 and then Is_Type (Entity (P))
1563 and then Ekind (Entity (P)) = E_Incomplete_Type
1565 P_Type := Get_Full_View (P_Type);
1566 Set_Entity (P, P_Type);
1567 Set_Etype (P, P_Type);
1570 if P_Type = Any_Type then
1571 raise Bad_Attribute;
1574 P_Base_Type := Base_Type (P_Type);
1577 -- Analyze expressions that may be present, exiting if an error occurs
1584 E1 := First (Exprs);
1587 -- Check for missing or bad expression (result of previous error)
1589 if No (E1) or else Etype (E1) = Any_Type then
1590 raise Bad_Attribute;
1595 if Present (E2) then
1598 if Etype (E2) = Any_Type then
1599 raise Bad_Attribute;
1602 if Present (Next (E2)) then
1603 Unexpected_Argument (Next (E2));
1608 if Is_Overloaded (P)
1609 and then Aname /= Name_Access
1610 and then Aname /= Name_Address
1611 and then Aname /= Name_Code_Address
1612 and then Aname /= Name_Count
1613 and then Aname /= Name_Unchecked_Access
1615 Error_Attr ("ambiguous prefix for % attribute", P);
1618 -- Remaining processing depends on attribute
1626 when Attribute_Abort_Signal =>
1627 Check_Standard_Prefix;
1629 New_Reference_To (Stand.Abort_Signal, Loc));
1636 when Attribute_Access =>
1637 Analyze_Access_Attribute;
1643 when Attribute_Address =>
1646 -- Check for some junk cases, where we have to allow the address
1647 -- attribute but it does not make much sense, so at least for now
1648 -- just replace with Null_Address.
1650 -- We also do this if the prefix is a reference to the AST_Entry
1651 -- attribute. If expansion is active, the attribute will be
1652 -- replaced by a function call, and address will work fine and
1653 -- get the proper value, but if expansion is not active, then
1654 -- the check here allows proper semantic analysis of the reference.
1656 -- An Address attribute created by expansion is legal even when it
1657 -- applies to other entity-denoting expressions.
1659 if Is_Entity_Name (P) then
1661 Ent : constant Entity_Id := Entity (P);
1664 if Is_Subprogram (Ent) then
1665 if not Is_Library_Level_Entity (Ent) then
1666 Check_Restriction (No_Implicit_Dynamic_Code, P);
1669 Set_Address_Taken (Ent);
1671 elsif Is_Object (Ent)
1672 or else Ekind (Ent) = E_Label
1674 Set_Address_Taken (Ent);
1676 -- If we have an address of an object, and the attribute
1677 -- comes from source, then set the object as potentially
1678 -- source modified. We do this because the resulting address
1679 -- can potentially be used to modify the variable and we
1680 -- might not detect this, leading to some junk warnings.
1682 Set_Never_Set_In_Source (Ent, False);
1684 elsif (Is_Concurrent_Type (Etype (Ent))
1685 and then Etype (Ent) = Base_Type (Ent))
1686 or else Ekind (Ent) = E_Package
1687 or else Is_Generic_Unit (Ent)
1690 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
1693 Error_Attr ("invalid prefix for % attribute", P);
1697 elsif Nkind (P) = N_Attribute_Reference
1698 and then Attribute_Name (P) = Name_AST_Entry
1701 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
1703 elsif Is_Object_Reference (P) then
1706 elsif Nkind (P) = N_Selected_Component
1707 and then Is_Subprogram (Entity (Selector_Name (P)))
1711 -- What exactly are we allowing here ??? and is this properly
1712 -- documented in the sinfo documentation for this node ???
1714 elsif not Comes_From_Source (N) then
1718 Error_Attr ("invalid prefix for % attribute", P);
1721 Set_Etype (N, RTE (RE_Address));
1727 when Attribute_Address_Size =>
1728 Standard_Attribute (System_Address_Size);
1734 when Attribute_Adjacent =>
1735 Check_Floating_Point_Type_2;
1736 Set_Etype (N, P_Base_Type);
1737 Resolve (E1, P_Base_Type);
1738 Resolve (E2, P_Base_Type);
1744 when Attribute_Aft =>
1745 Check_Fixed_Point_Type_0;
1746 Set_Etype (N, Universal_Integer);
1752 when Attribute_Alignment =>
1754 -- Don't we need more checking here, cf Size ???
1757 Check_Not_Incomplete_Type;
1758 Set_Etype (N, Universal_Integer);
1764 when Attribute_Asm_Input =>
1765 Check_Asm_Attribute;
1766 Set_Etype (N, RTE (RE_Asm_Input_Operand));
1772 when Attribute_Asm_Output =>
1773 Check_Asm_Attribute;
1775 if Etype (E2) = Any_Type then
1778 elsif Aname = Name_Asm_Output then
1779 if not Is_Variable (E2) then
1781 ("second argument for Asm_Output is not variable", E2);
1785 Note_Possible_Modification (E2);
1786 Set_Etype (N, RTE (RE_Asm_Output_Operand));
1792 when Attribute_AST_Entry => AST_Entry : declare
1798 -- Indicates if entry family index is present. Note the coding
1799 -- here handles the entry family case, but in fact it cannot be
1800 -- executed currently, because pragma AST_Entry does not permit
1801 -- the specification of an entry family.
1803 procedure Bad_AST_Entry;
1804 -- Signal a bad AST_Entry pragma
1806 function OK_Entry (E : Entity_Id) return Boolean;
1807 -- Checks that E is of an appropriate entity kind for an entry
1808 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
1809 -- is set True for the entry family case). In the True case,
1810 -- makes sure that Is_AST_Entry is set on the entry.
1812 procedure Bad_AST_Entry is
1814 Error_Attr ("prefix for % attribute must be task entry", P);
1817 function OK_Entry (E : Entity_Id) return Boolean is
1822 Result := (Ekind (E) = E_Entry_Family);
1824 Result := (Ekind (E) = E_Entry);
1828 if not Is_AST_Entry (E) then
1829 Error_Msg_Name_2 := Aname;
1831 ("% attribute requires previous % pragma", P);
1838 -- Start of processing for AST_Entry
1844 -- Deal with entry family case
1846 if Nkind (P) = N_Indexed_Component then
1854 Ptyp := Etype (Pref);
1856 if Ptyp = Any_Type or else Error_Posted (Pref) then
1860 -- If the prefix is a selected component whose prefix is of an
1861 -- access type, then introduce an explicit dereference.
1862 -- ??? Could we reuse Check_Dereference here?
1864 if Nkind (Pref) = N_Selected_Component
1865 and then Is_Access_Type (Ptyp)
1868 Make_Explicit_Dereference (Sloc (Pref),
1869 Relocate_Node (Pref)));
1870 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
1873 -- Prefix can be of the form a.b, where a is a task object
1874 -- and b is one of the entries of the corresponding task type.
1876 if Nkind (Pref) = N_Selected_Component
1877 and then OK_Entry (Entity (Selector_Name (Pref)))
1878 and then Is_Object_Reference (Prefix (Pref))
1879 and then Is_Task_Type (Etype (Prefix (Pref)))
1883 -- Otherwise the prefix must be an entry of a containing task,
1884 -- or of a variable of the enclosing task type.
1887 if Nkind (Pref) = N_Identifier
1888 or else Nkind (Pref) = N_Expanded_Name
1890 Ent := Entity (Pref);
1892 if not OK_Entry (Ent)
1893 or else not In_Open_Scopes (Scope (Ent))
1903 Set_Etype (N, RTE (RE_AST_Handler));
1910 -- Note: when the base attribute appears in the context of a subtype
1911 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
1912 -- the following circuit.
1914 when Attribute_Base => Base : declare
1918 Check_Either_E0_Or_E1;
1922 if Ada_Version >= Ada_95
1923 and then not Is_Scalar_Type (Typ)
1924 and then not Is_Generic_Type (Typ)
1926 Error_Msg_N ("prefix of Base attribute must be scalar type", N);
1928 elsif Sloc (Typ) = Standard_Location
1929 and then Base_Type (Typ) = Typ
1930 and then Warn_On_Redundant_Constructs
1933 ("?redudant attribute, & is its own base type", N, Typ);
1936 Set_Etype (N, Base_Type (Entity (P)));
1938 -- If we have an expression present, then really this is a conversion
1939 -- and the tree must be reformed. Note that this is one of the cases
1940 -- in which we do a replace rather than a rewrite, because the
1941 -- original tree is junk.
1943 if Present (E1) then
1945 Make_Type_Conversion (Loc,
1947 Make_Attribute_Reference (Loc,
1948 Prefix => Prefix (N),
1949 Attribute_Name => Name_Base),
1950 Expression => Relocate_Node (E1)));
1952 -- E1 may be overloaded, and its interpretations preserved.
1954 Save_Interps (E1, Expression (N));
1957 -- For other cases, set the proper type as the entity of the
1958 -- attribute reference, and then rewrite the node to be an
1959 -- occurrence of the referenced base type. This way, no one
1960 -- else in the compiler has to worry about the base attribute.
1963 Set_Entity (N, Base_Type (Entity (P)));
1965 New_Reference_To (Entity (N), Loc));
1974 when Attribute_Bit => Bit :
1978 if not Is_Object_Reference (P) then
1979 Error_Attr ("prefix for % attribute must be object", P);
1981 -- What about the access object cases ???
1987 Set_Etype (N, Universal_Integer);
1994 when Attribute_Bit_Order => Bit_Order :
1999 if not Is_Record_Type (P_Type) then
2000 Error_Attr ("prefix of % attribute must be record type", P);
2003 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2005 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2008 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2011 Set_Etype (N, RTE (RE_Bit_Order));
2014 -- Reset incorrect indication of staticness
2016 Set_Is_Static_Expression (N, False);
2023 -- Note: in generated code, we can have a Bit_Position attribute
2024 -- applied to a (naked) record component (i.e. the prefix is an
2025 -- identifier that references an E_Component or E_Discriminant
2026 -- entity directly, and this is interpreted as expected by Gigi.
2027 -- The following code will not tolerate such usage, but when the
2028 -- expander creates this special case, it marks it as analyzed
2029 -- immediately and sets an appropriate type.
2031 when Attribute_Bit_Position =>
2033 if Comes_From_Source (N) then
2037 Set_Etype (N, Universal_Integer);
2043 when Attribute_Body_Version =>
2046 Set_Etype (N, RTE (RE_Version_String));
2052 when Attribute_Callable =>
2054 Set_Etype (N, Standard_Boolean);
2061 when Attribute_Caller => Caller : declare
2068 if Nkind (P) = N_Identifier
2069 or else Nkind (P) = N_Expanded_Name
2073 if not Is_Entry (Ent) then
2074 Error_Attr ("invalid entry name", N);
2078 Error_Attr ("invalid entry name", N);
2082 for J in reverse 0 .. Scope_Stack.Last loop
2083 S := Scope_Stack.Table (J).Entity;
2085 if S = Scope (Ent) then
2086 Error_Attr ("Caller must appear in matching accept or body", N);
2092 Set_Etype (N, RTE (RO_AT_Task_Id));
2099 when Attribute_Ceiling =>
2100 Check_Floating_Point_Type_1;
2101 Set_Etype (N, P_Base_Type);
2102 Resolve (E1, P_Base_Type);
2108 when Attribute_Class => Class : declare
2110 Check_Restriction (No_Dispatch, N);
2111 Check_Either_E0_Or_E1;
2113 -- If we have an expression present, then really this is a conversion
2114 -- and the tree must be reformed into a proper conversion. This is a
2115 -- Replace rather than a Rewrite, because the original tree is junk.
2116 -- If expression is overloaded, propagate interpretations to new one.
2118 if Present (E1) then
2120 Make_Type_Conversion (Loc,
2122 Make_Attribute_Reference (Loc,
2123 Prefix => Prefix (N),
2124 Attribute_Name => Name_Class),
2125 Expression => Relocate_Node (E1)));
2127 Save_Interps (E1, Expression (N));
2130 -- Otherwise we just need to find the proper type
2142 when Attribute_Code_Address =>
2145 if Nkind (P) = N_Attribute_Reference
2146 and then (Attribute_Name (P) = Name_Elab_Body
2148 Attribute_Name (P) = Name_Elab_Spec)
2152 elsif not Is_Entity_Name (P)
2153 or else (Ekind (Entity (P)) /= E_Function
2155 Ekind (Entity (P)) /= E_Procedure)
2157 Error_Attr ("invalid prefix for % attribute", P);
2158 Set_Address_Taken (Entity (P));
2161 Set_Etype (N, RTE (RE_Address));
2163 --------------------
2164 -- Component_Size --
2165 --------------------
2167 when Attribute_Component_Size =>
2169 Set_Etype (N, Universal_Integer);
2171 -- Note: unlike other array attributes, unconstrained arrays are OK
2173 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2183 when Attribute_Compose =>
2184 Check_Floating_Point_Type_2;
2185 Set_Etype (N, P_Base_Type);
2186 Resolve (E1, P_Base_Type);
2187 Resolve (E2, Any_Integer);
2193 when Attribute_Constrained =>
2195 Set_Etype (N, Standard_Boolean);
2197 -- Case from RM J.4(2) of constrained applied to private type
2199 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2201 -- If we are within an instance, the attribute must be legal
2202 -- because it was valid in the generic unit. Ditto if this is
2203 -- an inlining of a function declared in an instance.
2206 or else In_Inlined_Body
2210 -- For sure OK if we have a real private type itself, but must
2211 -- be completed, cannot apply Constrained to incomplete type.
2213 elsif Is_Private_Type (Entity (P)) then
2215 -- Note: this is one of the Annex J features that does not
2216 -- generate a warning from -gnatwj, since in fact it seems
2217 -- very useful, and is used in the GNAT runtime.
2219 Check_Not_Incomplete_Type;
2223 -- Normal (non-obsolescent case) of application to object of
2224 -- a discriminated type.
2227 Check_Object_Reference (P);
2229 -- If N does not come from source, then we allow the
2230 -- the attribute prefix to be of a private type whose
2231 -- full type has discriminants. This occurs in cases
2232 -- involving expanded calls to stream attributes.
2234 if not Comes_From_Source (N) then
2235 P_Type := Underlying_Type (P_Type);
2238 -- Must have discriminants or be an access type designating
2239 -- a type with discriminants. If it is a classwide type is
2240 -- has unknown discriminants.
2242 if Has_Discriminants (P_Type)
2243 or else Has_Unknown_Discriminants (P_Type)
2245 (Is_Access_Type (P_Type)
2246 and then Has_Discriminants (Designated_Type (P_Type)))
2250 -- Also allow an object of a generic type if extensions allowed
2251 -- and allow this for any type at all.
2253 elsif (Is_Generic_Type (P_Type)
2254 or else Is_Generic_Actual_Type (P_Type))
2255 and then Extensions_Allowed
2261 -- Fall through if bad prefix
2264 ("prefix of % attribute must be object of discriminated type", P);
2270 when Attribute_Copy_Sign =>
2271 Check_Floating_Point_Type_2;
2272 Set_Etype (N, P_Base_Type);
2273 Resolve (E1, P_Base_Type);
2274 Resolve (E2, P_Base_Type);
2280 when Attribute_Count => Count :
2289 if Nkind (P) = N_Identifier
2290 or else Nkind (P) = N_Expanded_Name
2294 if Ekind (Ent) /= E_Entry then
2295 Error_Attr ("invalid entry name", N);
2298 elsif Nkind (P) = N_Indexed_Component then
2299 if not Is_Entity_Name (Prefix (P))
2300 or else No (Entity (Prefix (P)))
2301 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2303 if Nkind (Prefix (P)) = N_Selected_Component
2304 and then Present (Entity (Selector_Name (Prefix (P))))
2305 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2309 ("attribute % must apply to entry of current task", P);
2312 Error_Attr ("invalid entry family name", P);
2317 Ent := Entity (Prefix (P));
2320 elsif Nkind (P) = N_Selected_Component
2321 and then Present (Entity (Selector_Name (P)))
2322 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2325 ("attribute % must apply to entry of current task", P);
2328 Error_Attr ("invalid entry name", N);
2332 for J in reverse 0 .. Scope_Stack.Last loop
2333 S := Scope_Stack.Table (J).Entity;
2335 if S = Scope (Ent) then
2336 if Nkind (P) = N_Expanded_Name then
2337 Tsk := Entity (Prefix (P));
2339 -- The prefix denotes either the task type, or else a
2340 -- single task whose task type is being analyzed.
2345 or else (not Is_Type (Tsk)
2346 and then Etype (Tsk) = S
2347 and then not (Comes_From_Source (S)))
2352 ("Attribute % must apply to entry of current task", N);
2358 elsif Ekind (Scope (Ent)) in Task_Kind
2359 and then Ekind (S) /= E_Loop
2360 and then Ekind (S) /= E_Block
2361 and then Ekind (S) /= E_Entry
2362 and then Ekind (S) /= E_Entry_Family
2364 Error_Attr ("Attribute % cannot appear in inner unit", N);
2366 elsif Ekind (Scope (Ent)) = E_Protected_Type
2367 and then not Has_Completion (Scope (Ent))
2369 Error_Attr ("attribute % can only be used inside body", N);
2373 if Is_Overloaded (P) then
2375 Index : Interp_Index;
2379 Get_First_Interp (P, Index, It);
2381 while Present (It.Nam) loop
2382 if It.Nam = Ent then
2386 Error_Attr ("ambiguous entry name", N);
2389 Get_Next_Interp (Index, It);
2394 Set_Etype (N, Universal_Integer);
2397 -----------------------
2398 -- Default_Bit_Order --
2399 -----------------------
2401 when Attribute_Default_Bit_Order => Default_Bit_Order :
2403 Check_Standard_Prefix;
2406 if Bytes_Big_Endian then
2408 Make_Integer_Literal (Loc, False_Value));
2411 Make_Integer_Literal (Loc, True_Value));
2414 Set_Etype (N, Universal_Integer);
2415 Set_Is_Static_Expression (N);
2416 end Default_Bit_Order;
2422 when Attribute_Definite =>
2423 Legal_Formal_Attribute;
2429 when Attribute_Delta =>
2430 Check_Fixed_Point_Type_0;
2431 Set_Etype (N, Universal_Real);
2437 when Attribute_Denorm =>
2438 Check_Floating_Point_Type_0;
2439 Set_Etype (N, Standard_Boolean);
2445 when Attribute_Digits =>
2449 if not Is_Floating_Point_Type (P_Type)
2450 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2453 ("prefix of % attribute must be float or decimal type", P);
2456 Set_Etype (N, Universal_Integer);
2462 -- Also handles processing for Elab_Spec
2464 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2466 Check_Unit_Name (P);
2467 Set_Etype (N, Standard_Void_Type);
2469 -- We have to manually call the expander in this case to get
2470 -- the necessary expansion (normally attributes that return
2471 -- entities are not expanded).
2479 -- Shares processing with Elab_Body
2485 when Attribute_Elaborated =>
2488 Set_Etype (N, Standard_Boolean);
2494 when Attribute_Emax =>
2495 Check_Floating_Point_Type_0;
2496 Set_Etype (N, Universal_Integer);
2502 when Attribute_Enum_Rep => Enum_Rep : declare
2504 if Present (E1) then
2506 Check_Discrete_Type;
2507 Resolve (E1, P_Base_Type);
2510 if not Is_Entity_Name (P)
2511 or else (not Is_Object (Entity (P))
2513 Ekind (Entity (P)) /= E_Enumeration_Literal)
2516 ("prefix of %attribute must be " &
2517 "discrete type/object or enum literal", P);
2521 Set_Etype (N, Universal_Integer);
2528 when Attribute_Epsilon =>
2529 Check_Floating_Point_Type_0;
2530 Set_Etype (N, Universal_Real);
2536 when Attribute_Exponent =>
2537 Check_Floating_Point_Type_1;
2538 Set_Etype (N, Universal_Integer);
2539 Resolve (E1, P_Base_Type);
2545 when Attribute_External_Tag =>
2549 Set_Etype (N, Standard_String);
2551 if not Is_Tagged_Type (P_Type) then
2552 Error_Attr ("prefix of % attribute must be tagged", P);
2559 when Attribute_First =>
2560 Check_Array_Or_Scalar_Type;
2566 when Attribute_First_Bit =>
2568 Set_Etype (N, Universal_Integer);
2574 when Attribute_Fixed_Value =>
2576 Check_Fixed_Point_Type;
2577 Resolve (E1, Any_Integer);
2578 Set_Etype (N, P_Base_Type);
2584 when Attribute_Floor =>
2585 Check_Floating_Point_Type_1;
2586 Set_Etype (N, P_Base_Type);
2587 Resolve (E1, P_Base_Type);
2593 when Attribute_Fore =>
2594 Check_Fixed_Point_Type_0;
2595 Set_Etype (N, Universal_Integer);
2601 when Attribute_Fraction =>
2602 Check_Floating_Point_Type_1;
2603 Set_Etype (N, P_Base_Type);
2604 Resolve (E1, P_Base_Type);
2606 -----------------------
2607 -- Has_Access_Values --
2608 -----------------------
2610 when Attribute_Has_Access_Values =>
2613 Set_Etype (N, Standard_Boolean);
2615 -----------------------
2616 -- Has_Discriminants --
2617 -----------------------
2619 when Attribute_Has_Discriminants =>
2620 Legal_Formal_Attribute;
2626 when Attribute_Identity =>
2630 if Etype (P) = Standard_Exception_Type then
2631 Set_Etype (N, RTE (RE_Exception_Id));
2633 elsif Is_Task_Type (Etype (P))
2634 or else (Is_Access_Type (Etype (P))
2635 and then Is_Task_Type (Designated_Type (Etype (P))))
2638 Set_Etype (N, RTE (RO_AT_Task_Id));
2641 Error_Attr ("prefix of % attribute must be a task or an "
2649 when Attribute_Image => Image :
2651 Set_Etype (N, Standard_String);
2654 if Is_Real_Type (P_Type) then
2655 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
2656 Error_Msg_Name_1 := Aname;
2658 ("(Ada 83) % attribute not allowed for real types", N);
2662 if Is_Enumeration_Type (P_Type) then
2663 Check_Restriction (No_Enumeration_Maps, N);
2667 Resolve (E1, P_Base_Type);
2669 Validate_Non_Static_Attribute_Function_Call;
2676 when Attribute_Img => Img :
2678 Set_Etype (N, Standard_String);
2680 if not Is_Scalar_Type (P_Type)
2681 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
2684 ("prefix of % attribute must be scalar object name", N);
2694 when Attribute_Input =>
2696 Check_Stream_Attribute (TSS_Stream_Input);
2697 Set_Etype (N, P_Base_Type);
2703 when Attribute_Integer_Value =>
2706 Resolve (E1, Any_Fixed);
2707 Set_Etype (N, P_Base_Type);
2713 when Attribute_Large =>
2716 Set_Etype (N, Universal_Real);
2722 when Attribute_Last =>
2723 Check_Array_Or_Scalar_Type;
2729 when Attribute_Last_Bit =>
2731 Set_Etype (N, Universal_Integer);
2737 when Attribute_Leading_Part =>
2738 Check_Floating_Point_Type_2;
2739 Set_Etype (N, P_Base_Type);
2740 Resolve (E1, P_Base_Type);
2741 Resolve (E2, Any_Integer);
2747 when Attribute_Length =>
2749 Set_Etype (N, Universal_Integer);
2755 when Attribute_Machine =>
2756 Check_Floating_Point_Type_1;
2757 Set_Etype (N, P_Base_Type);
2758 Resolve (E1, P_Base_Type);
2764 when Attribute_Machine_Emax =>
2765 Check_Floating_Point_Type_0;
2766 Set_Etype (N, Universal_Integer);
2772 when Attribute_Machine_Emin =>
2773 Check_Floating_Point_Type_0;
2774 Set_Etype (N, Universal_Integer);
2776 ----------------------
2777 -- Machine_Mantissa --
2778 ----------------------
2780 when Attribute_Machine_Mantissa =>
2781 Check_Floating_Point_Type_0;
2782 Set_Etype (N, Universal_Integer);
2784 -----------------------
2785 -- Machine_Overflows --
2786 -----------------------
2788 when Attribute_Machine_Overflows =>
2791 Set_Etype (N, Standard_Boolean);
2797 when Attribute_Machine_Radix =>
2800 Set_Etype (N, Universal_Integer);
2802 --------------------
2803 -- Machine_Rounds --
2804 --------------------
2806 when Attribute_Machine_Rounds =>
2809 Set_Etype (N, Standard_Boolean);
2815 when Attribute_Machine_Size =>
2818 Check_Not_Incomplete_Type;
2819 Set_Etype (N, Universal_Integer);
2825 when Attribute_Mantissa =>
2828 Set_Etype (N, Universal_Integer);
2834 when Attribute_Max =>
2837 Resolve (E1, P_Base_Type);
2838 Resolve (E2, P_Base_Type);
2839 Set_Etype (N, P_Base_Type);
2841 ----------------------------------
2842 -- Max_Size_In_Storage_Elements --
2843 ----------------------------------
2845 when Attribute_Max_Size_In_Storage_Elements =>
2848 Check_Not_Incomplete_Type;
2849 Set_Etype (N, Universal_Integer);
2851 -----------------------
2852 -- Maximum_Alignment --
2853 -----------------------
2855 when Attribute_Maximum_Alignment =>
2856 Standard_Attribute (Ttypes.Maximum_Alignment);
2858 --------------------
2859 -- Mechanism_Code --
2860 --------------------
2862 when Attribute_Mechanism_Code =>
2863 if not Is_Entity_Name (P)
2864 or else not Is_Subprogram (Entity (P))
2866 Error_Attr ("prefix of % attribute must be subprogram", P);
2869 Check_Either_E0_Or_E1;
2871 if Present (E1) then
2872 Resolve (E1, Any_Integer);
2873 Set_Etype (E1, Standard_Integer);
2875 if not Is_Static_Expression (E1) then
2876 Flag_Non_Static_Expr
2877 ("expression for parameter number must be static!", E1);
2880 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
2881 or else UI_To_Int (Intval (E1)) < 0
2883 Error_Attr ("invalid parameter number for %attribute", E1);
2887 Set_Etype (N, Universal_Integer);
2893 when Attribute_Min =>
2896 Resolve (E1, P_Base_Type);
2897 Resolve (E2, P_Base_Type);
2898 Set_Etype (N, P_Base_Type);
2904 when Attribute_Model =>
2905 Check_Floating_Point_Type_1;
2906 Set_Etype (N, P_Base_Type);
2907 Resolve (E1, P_Base_Type);
2913 when Attribute_Model_Emin =>
2914 Check_Floating_Point_Type_0;
2915 Set_Etype (N, Universal_Integer);
2921 when Attribute_Model_Epsilon =>
2922 Check_Floating_Point_Type_0;
2923 Set_Etype (N, Universal_Real);
2925 --------------------
2926 -- Model_Mantissa --
2927 --------------------
2929 when Attribute_Model_Mantissa =>
2930 Check_Floating_Point_Type_0;
2931 Set_Etype (N, Universal_Integer);
2937 when Attribute_Model_Small =>
2938 Check_Floating_Point_Type_0;
2939 Set_Etype (N, Universal_Real);
2945 when Attribute_Modulus =>
2949 if not Is_Modular_Integer_Type (P_Type) then
2950 Error_Attr ("prefix of % attribute must be modular type", P);
2953 Set_Etype (N, Universal_Integer);
2955 --------------------
2956 -- Null_Parameter --
2957 --------------------
2959 when Attribute_Null_Parameter => Null_Parameter : declare
2960 Parnt : constant Node_Id := Parent (N);
2961 GParnt : constant Node_Id := Parent (Parnt);
2963 procedure Bad_Null_Parameter (Msg : String);
2964 -- Used if bad Null parameter attribute node is found. Issues
2965 -- given error message, and also sets the type to Any_Type to
2966 -- avoid blowups later on from dealing with a junk node.
2968 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
2969 -- Called to check that Proc_Ent is imported subprogram
2971 ------------------------
2972 -- Bad_Null_Parameter --
2973 ------------------------
2975 procedure Bad_Null_Parameter (Msg : String) is
2977 Error_Msg_N (Msg, N);
2978 Set_Etype (N, Any_Type);
2979 end Bad_Null_Parameter;
2981 ----------------------
2982 -- Must_Be_Imported --
2983 ----------------------
2985 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
2986 Pent : Entity_Id := Proc_Ent;
2989 while Present (Alias (Pent)) loop
2990 Pent := Alias (Pent);
2993 -- Ignore check if procedure not frozen yet (we will get
2994 -- another chance when the default parameter is reanalyzed)
2996 if not Is_Frozen (Pent) then
2999 elsif not Is_Imported (Pent) then
3001 ("Null_Parameter can only be used with imported subprogram");
3006 end Must_Be_Imported;
3008 -- Start of processing for Null_Parameter
3013 Set_Etype (N, P_Type);
3015 -- Case of attribute used as default expression
3017 if Nkind (Parnt) = N_Parameter_Specification then
3018 Must_Be_Imported (Defining_Entity (GParnt));
3020 -- Case of attribute used as actual for subprogram (positional)
3022 elsif (Nkind (Parnt) = N_Procedure_Call_Statement
3024 Nkind (Parnt) = N_Function_Call)
3025 and then Is_Entity_Name (Name (Parnt))
3027 Must_Be_Imported (Entity (Name (Parnt)));
3029 -- Case of attribute used as actual for subprogram (named)
3031 elsif Nkind (Parnt) = N_Parameter_Association
3032 and then (Nkind (GParnt) = N_Procedure_Call_Statement
3034 Nkind (GParnt) = N_Function_Call)
3035 and then Is_Entity_Name (Name (GParnt))
3037 Must_Be_Imported (Entity (Name (GParnt)));
3039 -- Not an allowed case
3043 ("Null_Parameter must be actual or default parameter");
3052 when Attribute_Object_Size =>
3055 Check_Not_Incomplete_Type;
3056 Set_Etype (N, Universal_Integer);
3062 when Attribute_Output =>
3064 Check_Stream_Attribute (TSS_Stream_Output);
3065 Set_Etype (N, Standard_Void_Type);
3066 Resolve (N, Standard_Void_Type);
3072 when Attribute_Partition_ID =>
3075 if P_Type /= Any_Type then
3076 if not Is_Library_Level_Entity (Entity (P)) then
3078 ("prefix of % attribute must be library-level entity", P);
3080 -- The defining entity of prefix should not be declared inside
3081 -- a Pure unit. RM E.1(8).
3082 -- The Is_Pure flag has been set during declaration.
3084 elsif Is_Entity_Name (P)
3085 and then Is_Pure (Entity (P))
3088 ("prefix of % attribute must not be declared pure", P);
3092 Set_Etype (N, Universal_Integer);
3094 -------------------------
3095 -- Passed_By_Reference --
3096 -------------------------
3098 when Attribute_Passed_By_Reference =>
3101 Set_Etype (N, Standard_Boolean);
3107 when Attribute_Pool_Address =>
3109 Set_Etype (N, RTE (RE_Address));
3115 when Attribute_Pos =>
3116 Check_Discrete_Type;
3118 Resolve (E1, P_Base_Type);
3119 Set_Etype (N, Universal_Integer);
3125 when Attribute_Position =>
3127 Set_Etype (N, Universal_Integer);
3133 when Attribute_Pred =>
3136 Resolve (E1, P_Base_Type);
3137 Set_Etype (N, P_Base_Type);
3139 -- Nothing to do for real type case
3141 if Is_Real_Type (P_Type) then
3144 -- If not modular type, test for overflow check required
3147 if not Is_Modular_Integer_Type (P_Type)
3148 and then not Range_Checks_Suppressed (P_Base_Type)
3150 Enable_Range_Check (E1);
3158 when Attribute_Range =>
3159 Check_Array_Or_Scalar_Type;
3161 if Ada_Version = Ada_83
3162 and then Is_Scalar_Type (P_Type)
3163 and then Comes_From_Source (N)
3166 ("(Ada 83) % attribute not allowed for scalar type", P);
3173 when Attribute_Range_Length =>
3174 Check_Discrete_Type;
3175 Set_Etype (N, Universal_Integer);
3181 when Attribute_Read =>
3183 Check_Stream_Attribute (TSS_Stream_Read);
3184 Set_Etype (N, Standard_Void_Type);
3185 Resolve (N, Standard_Void_Type);
3186 Note_Possible_Modification (E2);
3192 when Attribute_Remainder =>
3193 Check_Floating_Point_Type_2;
3194 Set_Etype (N, P_Base_Type);
3195 Resolve (E1, P_Base_Type);
3196 Resolve (E2, P_Base_Type);
3202 when Attribute_Round =>
3204 Check_Decimal_Fixed_Point_Type;
3205 Set_Etype (N, P_Base_Type);
3207 -- Because the context is universal_real (3.5.10(12)) it is a legal
3208 -- context for a universal fixed expression. This is the only
3209 -- attribute whose functional description involves U_R.
3211 if Etype (E1) = Universal_Fixed then
3213 Conv : constant Node_Id := Make_Type_Conversion (Loc,
3214 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
3215 Expression => Relocate_Node (E1));
3223 Resolve (E1, Any_Real);
3229 when Attribute_Rounding =>
3230 Check_Floating_Point_Type_1;
3231 Set_Etype (N, P_Base_Type);
3232 Resolve (E1, P_Base_Type);
3238 when Attribute_Safe_Emax =>
3239 Check_Floating_Point_Type_0;
3240 Set_Etype (N, Universal_Integer);
3246 when Attribute_Safe_First =>
3247 Check_Floating_Point_Type_0;
3248 Set_Etype (N, Universal_Real);
3254 when Attribute_Safe_Large =>
3257 Set_Etype (N, Universal_Real);
3263 when Attribute_Safe_Last =>
3264 Check_Floating_Point_Type_0;
3265 Set_Etype (N, Universal_Real);
3271 when Attribute_Safe_Small =>
3274 Set_Etype (N, Universal_Real);
3280 when Attribute_Scale =>
3282 Check_Decimal_Fixed_Point_Type;
3283 Set_Etype (N, Universal_Integer);
3289 when Attribute_Scaling =>
3290 Check_Floating_Point_Type_2;
3291 Set_Etype (N, P_Base_Type);
3292 Resolve (E1, P_Base_Type);
3298 when Attribute_Signed_Zeros =>
3299 Check_Floating_Point_Type_0;
3300 Set_Etype (N, Standard_Boolean);
3306 when Attribute_Size | Attribute_VADS_Size =>
3309 if Is_Object_Reference (P)
3310 or else (Is_Entity_Name (P)
3311 and then Ekind (Entity (P)) = E_Function)
3313 Check_Object_Reference (P);
3315 elsif Is_Entity_Name (P)
3316 and then Is_Type (Entity (P))
3320 elsif Nkind (P) = N_Type_Conversion
3321 and then not Comes_From_Source (P)
3326 Error_Attr ("invalid prefix for % attribute", P);
3329 Check_Not_Incomplete_Type;
3330 Set_Etype (N, Universal_Integer);
3336 when Attribute_Small =>
3339 Set_Etype (N, Universal_Real);
3345 when Attribute_Storage_Pool =>
3346 if Is_Access_Type (P_Type) then
3349 -- Set appropriate entity
3351 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
3352 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
3354 Set_Entity (N, RTE (RE_Global_Pool_Object));
3357 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
3359 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
3360 -- Storage_Pool since this attribute is not defined for such
3361 -- types (RM E.2.3(22)).
3363 Validate_Remote_Access_To_Class_Wide_Type (N);
3366 Error_Attr ("prefix of % attribute must be access type", P);
3373 when Attribute_Storage_Size =>
3375 if Is_Task_Type (P_Type) then
3377 Set_Etype (N, Universal_Integer);
3379 elsif Is_Access_Type (P_Type) then
3380 if Is_Entity_Name (P)
3381 and then Is_Type (Entity (P))
3385 Set_Etype (N, Universal_Integer);
3387 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
3388 -- Storage_Size since this attribute is not defined for
3389 -- such types (RM E.2.3(22)).
3391 Validate_Remote_Access_To_Class_Wide_Type (N);
3393 -- The prefix is allowed to be an implicit dereference
3394 -- of an access value designating a task.
3399 Set_Etype (N, Universal_Integer);
3404 ("prefix of % attribute must be access or task type", P);
3411 when Attribute_Storage_Unit =>
3412 Standard_Attribute (Ttypes.System_Storage_Unit);
3418 when Attribute_Succ =>
3421 Resolve (E1, P_Base_Type);
3422 Set_Etype (N, P_Base_Type);
3424 -- Nothing to do for real type case
3426 if Is_Real_Type (P_Type) then
3429 -- If not modular type, test for overflow check required.
3432 if not Is_Modular_Integer_Type (P_Type)
3433 and then not Range_Checks_Suppressed (P_Base_Type)
3435 Enable_Range_Check (E1);
3443 when Attribute_Tag =>
3447 if not Is_Tagged_Type (P_Type) then
3448 Error_Attr ("prefix of % attribute must be tagged", P);
3450 -- Next test does not apply to generated code
3451 -- why not, and what does the illegal reference mean???
3453 elsif Is_Object_Reference (P)
3454 and then not Is_Class_Wide_Type (P_Type)
3455 and then Comes_From_Source (N)
3458 ("% attribute can only be applied to objects of class-wide type",
3462 Set_Etype (N, RTE (RE_Tag));
3468 when Attribute_Target_Name => Target_Name : declare
3469 TN : constant String := Sdefault.Target_Name.all;
3470 TL : Integer := TN'Last;
3473 Check_Standard_Prefix;
3477 if TN (TL) = '/' or else TN (TL) = '\' then
3481 Store_String_Chars (TN (TN'First .. TL));
3484 Make_String_Literal (Loc,
3485 Strval => End_String));
3486 Analyze_And_Resolve (N, Standard_String);
3493 when Attribute_Terminated =>
3495 Set_Etype (N, Standard_Boolean);
3502 when Attribute_To_Address =>
3506 if Nkind (P) /= N_Identifier
3507 or else Chars (P) /= Name_System
3509 Error_Attr ("prefix of %attribute must be System", P);
3512 Generate_Reference (RTE (RE_Address), P);
3513 Analyze_And_Resolve (E1, Any_Integer);
3514 Set_Etype (N, RTE (RE_Address));
3520 when Attribute_Truncation =>
3521 Check_Floating_Point_Type_1;
3522 Resolve (E1, P_Base_Type);
3523 Set_Etype (N, P_Base_Type);
3529 when Attribute_Type_Class =>
3532 Check_Not_Incomplete_Type;
3533 Set_Etype (N, RTE (RE_Type_Class));
3539 when Attribute_UET_Address =>
3541 Check_Unit_Name (P);
3542 Set_Etype (N, RTE (RE_Address));
3544 -----------------------
3545 -- Unbiased_Rounding --
3546 -----------------------
3548 when Attribute_Unbiased_Rounding =>
3549 Check_Floating_Point_Type_1;
3550 Set_Etype (N, P_Base_Type);
3551 Resolve (E1, P_Base_Type);
3553 ----------------------
3554 -- Unchecked_Access --
3555 ----------------------
3557 when Attribute_Unchecked_Access =>
3558 if Comes_From_Source (N) then
3559 Check_Restriction (No_Unchecked_Access, N);
3562 Analyze_Access_Attribute;
3564 -------------------------
3565 -- Unconstrained_Array --
3566 -------------------------
3568 when Attribute_Unconstrained_Array =>
3571 Check_Not_Incomplete_Type;
3572 Set_Etype (N, Standard_Boolean);
3574 ------------------------------
3575 -- Universal_Literal_String --
3576 ------------------------------
3578 -- This is a GNAT specific attribute whose prefix must be a named
3579 -- number where the expression is either a single numeric literal,
3580 -- or a numeric literal immediately preceded by a minus sign. The
3581 -- result is equivalent to a string literal containing the text of
3582 -- the literal as it appeared in the source program with a possible
3583 -- leading minus sign.
3585 when Attribute_Universal_Literal_String => Universal_Literal_String :
3589 if not Is_Entity_Name (P)
3590 or else Ekind (Entity (P)) not in Named_Kind
3592 Error_Attr ("prefix for % attribute must be named number", P);
3599 Src : Source_Buffer_Ptr;
3602 Expr := Original_Node (Expression (Parent (Entity (P))));
3604 if Nkind (Expr) = N_Op_Minus then
3606 Expr := Original_Node (Right_Opnd (Expr));
3611 if Nkind (Expr) /= N_Integer_Literal
3612 and then Nkind (Expr) /= N_Real_Literal
3615 ("named number for % attribute must be simple literal", N);
3618 -- Build string literal corresponding to source literal text
3623 Store_String_Char (Get_Char_Code ('-'));
3627 Src := Source_Text (Get_Source_File_Index (S));
3629 while Src (S) /= ';' and then Src (S) /= ' ' loop
3630 Store_String_Char (Get_Char_Code (Src (S)));
3634 -- Now we rewrite the attribute with the string literal
3637 Make_String_Literal (Loc, End_String));
3641 end Universal_Literal_String;
3643 -------------------------
3644 -- Unrestricted_Access --
3645 -------------------------
3647 -- This is a GNAT specific attribute which is like Access except that
3648 -- all scope checks and checks for aliased views are omitted.
3650 when Attribute_Unrestricted_Access =>
3651 if Comes_From_Source (N) then
3652 Check_Restriction (No_Unchecked_Access, N);
3655 if Is_Entity_Name (P) then
3656 Set_Address_Taken (Entity (P));
3659 Analyze_Access_Attribute;
3665 when Attribute_Val => Val : declare
3668 Check_Discrete_Type;
3669 Resolve (E1, Any_Integer);
3670 Set_Etype (N, P_Base_Type);
3672 -- Note, we need a range check in general, but we wait for the
3673 -- Resolve call to do this, since we want to let Eval_Attribute
3674 -- have a chance to find an static illegality first!
3681 when Attribute_Valid =>
3684 -- Ignore check for object if we have a 'Valid reference generated
3685 -- by the expanded code, since in some cases valid checks can occur
3686 -- on items that are names, but are not objects (e.g. attributes).
3688 if Comes_From_Source (N) then
3689 Check_Object_Reference (P);
3692 if not Is_Scalar_Type (P_Type) then
3693 Error_Attr ("object for % attribute must be of scalar type", P);
3696 Set_Etype (N, Standard_Boolean);
3702 when Attribute_Value => Value :
3707 if Is_Enumeration_Type (P_Type) then
3708 Check_Restriction (No_Enumeration_Maps, N);
3711 -- Set Etype before resolving expression because expansion of
3712 -- expression may require enclosing type. Note that the type
3713 -- returned by 'Value is the base type of the prefix type.
3715 Set_Etype (N, P_Base_Type);
3716 Validate_Non_Static_Attribute_Function_Call;
3723 when Attribute_Value_Size =>
3726 Check_Not_Incomplete_Type;
3727 Set_Etype (N, Universal_Integer);
3733 when Attribute_Version =>
3736 Set_Etype (N, RTE (RE_Version_String));
3742 when Attribute_Wchar_T_Size =>
3743 Standard_Attribute (Interfaces_Wchar_T_Size);
3749 when Attribute_Wide_Image => Wide_Image :
3752 Set_Etype (N, Standard_Wide_String);
3754 Resolve (E1, P_Base_Type);
3755 Validate_Non_Static_Attribute_Function_Call;
3762 when Attribute_Wide_Value => Wide_Value :
3767 -- Set Etype before resolving expression because expansion
3768 -- of expression may require enclosing type.
3770 Set_Etype (N, P_Type);
3771 Validate_Non_Static_Attribute_Function_Call;
3778 when Attribute_Wide_Width =>
3781 Set_Etype (N, Universal_Integer);
3787 when Attribute_Width =>
3790 Set_Etype (N, Universal_Integer);
3796 when Attribute_Word_Size =>
3797 Standard_Attribute (System_Word_Size);
3803 when Attribute_Write =>
3805 Check_Stream_Attribute (TSS_Stream_Write);
3806 Set_Etype (N, Standard_Void_Type);
3807 Resolve (N, Standard_Void_Type);
3811 -- All errors raise Bad_Attribute, so that we get out before any further
3812 -- damage occurs when an error is detected (for example, if we check for
3813 -- one attribute expression, and the check succeeds, we want to be able
3814 -- to proceed securely assuming that an expression is in fact present.
3816 -- Note: we set the attribute analyzed in this case to prevent any
3817 -- attempt at reanalysis which could generate spurious error msgs.
3820 when Bad_Attribute =>
3822 Set_Etype (N, Any_Type);
3824 end Analyze_Attribute;
3826 --------------------
3827 -- Eval_Attribute --
3828 --------------------
3830 procedure Eval_Attribute (N : Node_Id) is
3831 Loc : constant Source_Ptr := Sloc (N);
3832 Aname : constant Name_Id := Attribute_Name (N);
3833 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
3834 P : constant Node_Id := Prefix (N);
3836 C_Type : constant Entity_Id := Etype (N);
3837 -- The type imposed by the context.
3840 -- First expression, or Empty if none
3843 -- Second expression, or Empty if none
3845 P_Entity : Entity_Id;
3846 -- Entity denoted by prefix
3849 -- The type of the prefix
3851 P_Base_Type : Entity_Id;
3852 -- The base type of the prefix type
3854 P_Root_Type : Entity_Id;
3855 -- The root type of the prefix type
3858 -- True if the result is Static. This is set by the general processing
3859 -- to true if the prefix is static, and all expressions are static. It
3860 -- can be reset as processing continues for particular attributes
3862 Lo_Bound, Hi_Bound : Node_Id;
3863 -- Expressions for low and high bounds of type or array index referenced
3864 -- by First, Last, or Length attribute for array, set by Set_Bounds.
3867 -- Constraint error node used if we have an attribute reference has
3868 -- an argument that raises a constraint error. In this case we replace
3869 -- the attribute with a raise constraint_error node. This is important
3870 -- processing, since otherwise gigi might see an attribute which it is
3871 -- unprepared to deal with.
3873 function Aft_Value return Nat;
3874 -- Computes Aft value for current attribute prefix (used by Aft itself
3875 -- and also by Width for computing the Width of a fixed point type).
3877 procedure Check_Expressions;
3878 -- In case where the attribute is not foldable, the expressions, if
3879 -- any, of the attribute, are in a non-static context. This procedure
3880 -- performs the required additional checks.
3882 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
3883 -- Determines if the given type has compile time known bounds. Note
3884 -- that we enter the case statement even in cases where the prefix
3885 -- type does NOT have known bounds, so it is important to guard any
3886 -- attempt to evaluate both bounds with a call to this function.
3888 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
3889 -- This procedure is called when the attribute N has a non-static
3890 -- but compile time known value given by Val. It includes the
3891 -- necessary checks for out of range values.
3893 procedure Float_Attribute_Universal_Integer
3902 -- This procedure evaluates a float attribute with no arguments that
3903 -- returns a universal integer result. The parameters give the values
3904 -- for the possible floating-point root types. See ttypef for details.
3905 -- The prefix type is a float type (and is thus not a generic type).
3907 procedure Float_Attribute_Universal_Real
3908 (IEEES_Val : String;
3915 AAMPL_Val : String);
3916 -- This procedure evaluates a float attribute with no arguments that
3917 -- returns a universal real result. The parameters give the values
3918 -- required for the possible floating-point root types in string
3919 -- format as real literals with a possible leading minus sign.
3920 -- The prefix type is a float type (and is thus not a generic type).
3922 function Fore_Value return Nat;
3923 -- Computes the Fore value for the current attribute prefix, which is
3924 -- known to be a static fixed-point type. Used by Fore and Width.
3926 function Mantissa return Uint;
3927 -- Returns the Mantissa value for the prefix type
3929 procedure Set_Bounds;
3930 -- Used for First, Last and Length attributes applied to an array or
3931 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
3932 -- and high bound expressions for the index referenced by the attribute
3933 -- designator (i.e. the first index if no expression is present, and
3934 -- the N'th index if the value N is present as an expression). Also
3935 -- used for First and Last of scalar types. Static is reset to False
3936 -- if the type or index type is not statically constrained.
3942 function Aft_Value return Nat is
3948 Delta_Val := Delta_Value (P_Type);
3950 while Delta_Val < Ureal_Tenth loop
3951 Delta_Val := Delta_Val * Ureal_10;
3952 Result := Result + 1;
3958 -----------------------
3959 -- Check_Expressions --
3960 -----------------------
3962 procedure Check_Expressions is
3966 while Present (E) loop
3967 Check_Non_Static_Context (E);
3970 end Check_Expressions;
3972 ----------------------------------
3973 -- Compile_Time_Known_Attribute --
3974 ----------------------------------
3976 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
3977 T : constant Entity_Id := Etype (N);
3980 Fold_Uint (N, Val, False);
3982 -- Check that result is in bounds of the type if it is static
3984 if Is_In_Range (N, T) then
3987 elsif Is_Out_Of_Range (N, T) then
3988 Apply_Compile_Time_Constraint_Error
3989 (N, "value not in range of}?", CE_Range_Check_Failed);
3991 elsif not Range_Checks_Suppressed (T) then
3992 Enable_Range_Check (N);
3995 Set_Do_Range_Check (N, False);
3997 end Compile_Time_Known_Attribute;
3999 -------------------------------
4000 -- Compile_Time_Known_Bounds --
4001 -------------------------------
4003 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
4006 Compile_Time_Known_Value (Type_Low_Bound (Typ))
4008 Compile_Time_Known_Value (Type_High_Bound (Typ));
4009 end Compile_Time_Known_Bounds;
4011 ---------------------------------------
4012 -- Float_Attribute_Universal_Integer --
4013 ---------------------------------------
4015 procedure Float_Attribute_Universal_Integer
4026 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4029 if Vax_Float (P_Base_Type) then
4030 if Digs = VAXFF_Digits then
4032 elsif Digs = VAXDF_Digits then
4034 else pragma Assert (Digs = VAXGF_Digits);
4038 elsif Is_AAMP_Float (P_Base_Type) then
4039 if Digs = AAMPS_Digits then
4041 else pragma Assert (Digs = AAMPL_Digits);
4046 if Digs = IEEES_Digits then
4048 elsif Digs = IEEEL_Digits then
4050 else pragma Assert (Digs = IEEEX_Digits);
4055 Fold_Uint (N, UI_From_Int (Val), True);
4056 end Float_Attribute_Universal_Integer;
4058 ------------------------------------
4059 -- Float_Attribute_Universal_Real --
4060 ------------------------------------
4062 procedure Float_Attribute_Universal_Real
4063 (IEEES_Val : String;
4073 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4076 if Vax_Float (P_Base_Type) then
4077 if Digs = VAXFF_Digits then
4078 Val := Real_Convert (VAXFF_Val);
4079 elsif Digs = VAXDF_Digits then
4080 Val := Real_Convert (VAXDF_Val);
4081 else pragma Assert (Digs = VAXGF_Digits);
4082 Val := Real_Convert (VAXGF_Val);
4085 elsif Is_AAMP_Float (P_Base_Type) then
4086 if Digs = AAMPS_Digits then
4087 Val := Real_Convert (AAMPS_Val);
4088 else pragma Assert (Digs = AAMPL_Digits);
4089 Val := Real_Convert (AAMPL_Val);
4093 if Digs = IEEES_Digits then
4094 Val := Real_Convert (IEEES_Val);
4095 elsif Digs = IEEEL_Digits then
4096 Val := Real_Convert (IEEEL_Val);
4097 else pragma Assert (Digs = IEEEX_Digits);
4098 Val := Real_Convert (IEEEX_Val);
4102 Set_Sloc (Val, Loc);
4104 Set_Is_Static_Expression (N, Static);
4105 Analyze_And_Resolve (N, C_Type);
4106 end Float_Attribute_Universal_Real;
4112 -- Note that the Fore calculation is based on the actual values
4113 -- of the bounds, and does not take into account possible rounding.
4115 function Fore_Value return Nat is
4116 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
4117 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
4118 Small : constant Ureal := Small_Value (P_Type);
4119 Lo_Real : constant Ureal := Lo * Small;
4120 Hi_Real : constant Ureal := Hi * Small;
4125 -- Bounds are given in terms of small units, so first compute
4126 -- proper values as reals.
4128 T := UR_Max (abs Lo_Real, abs Hi_Real);
4131 -- Loop to compute proper value if more than one digit required
4133 while T >= Ureal_10 loop
4145 -- Table of mantissa values accessed by function Computed using
4148 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
4150 -- where D is T'Digits (RM83 3.5.7)
4152 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
4194 function Mantissa return Uint is
4197 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
4204 procedure Set_Bounds is
4210 -- For a string literal subtype, we have to construct the bounds.
4211 -- Valid Ada code never applies attributes to string literals, but
4212 -- it is convenient to allow the expander to generate attribute
4213 -- references of this type (e.g. First and Last applied to a string
4216 -- Note that the whole point of the E_String_Literal_Subtype is to
4217 -- avoid this construction of bounds, but the cases in which we
4218 -- have to materialize them are rare enough that we don't worry!
4220 -- The low bound is simply the low bound of the base type. The
4221 -- high bound is computed from the length of the string and this
4224 if Ekind (P_Type) = E_String_Literal_Subtype then
4225 Ityp := Etype (First_Index (Base_Type (P_Type)));
4226 Lo_Bound := Type_Low_Bound (Ityp);
4229 Make_Integer_Literal (Sloc (P),
4231 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
4233 Set_Parent (Hi_Bound, P);
4234 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
4237 -- For non-array case, just get bounds of scalar type
4239 elsif Is_Scalar_Type (P_Type) then
4242 -- For a fixed-point type, we must freeze to get the attributes
4243 -- of the fixed-point type set now so we can reference them.
4245 if Is_Fixed_Point_Type (P_Type)
4246 and then not Is_Frozen (Base_Type (P_Type))
4247 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
4248 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
4250 Freeze_Fixed_Point_Type (Base_Type (P_Type));
4253 -- For array case, get type of proper index
4259 Ndim := UI_To_Int (Expr_Value (E1));
4262 Indx := First_Index (P_Type);
4263 for J in 1 .. Ndim - 1 loop
4267 -- If no index type, get out (some other error occurred, and
4268 -- we don't have enough information to complete the job!)
4276 Ityp := Etype (Indx);
4279 -- A discrete range in an index constraint is allowed to be a
4280 -- subtype indication. This is syntactically a pain, but should
4281 -- not propagate to the entity for the corresponding index subtype.
4282 -- After checking that the subtype indication is legal, the range
4283 -- of the subtype indication should be transfered to the entity.
4284 -- The attributes for the bounds should remain the simple retrievals
4285 -- that they are now.
4287 Lo_Bound := Type_Low_Bound (Ityp);
4288 Hi_Bound := Type_High_Bound (Ityp);
4290 if not Is_Static_Subtype (Ityp) then
4295 -- Start of processing for Eval_Attribute
4298 -- Acquire first two expressions (at the moment, no attributes
4299 -- take more than two expressions in any case).
4301 if Present (Expressions (N)) then
4302 E1 := First (Expressions (N));
4309 -- Special processing for cases where the prefix is an object. For
4310 -- this purpose, a string literal counts as an object (attributes
4311 -- of string literals can only appear in generated code).
4313 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
4315 -- For Component_Size, the prefix is an array object, and we apply
4316 -- the attribute to the type of the object. This is allowed for
4317 -- both unconstrained and constrained arrays, since the bounds
4318 -- have no influence on the value of this attribute.
4320 if Id = Attribute_Component_Size then
4321 P_Entity := Etype (P);
4323 -- For First and Last, the prefix is an array object, and we apply
4324 -- the attribute to the type of the array, but we need a constrained
4325 -- type for this, so we use the actual subtype if available.
4327 elsif Id = Attribute_First
4331 Id = Attribute_Length
4334 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
4337 if Present (AS) and then Is_Constrained (AS) then
4340 -- If we have an unconstrained type, cannot fold
4348 -- For Size, give size of object if available, otherwise we
4349 -- cannot fold Size.
4351 elsif Id = Attribute_Size then
4352 if Is_Entity_Name (P)
4353 and then Known_Esize (Entity (P))
4355 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
4363 -- For Alignment, give size of object if available, otherwise we
4364 -- cannot fold Alignment.
4366 elsif Id = Attribute_Alignment then
4367 if Is_Entity_Name (P)
4368 and then Known_Alignment (Entity (P))
4370 Fold_Uint (N, Alignment (Entity (P)), False);
4378 -- No other attributes for objects are folded
4385 -- Cases where P is not an object. Cannot do anything if P is
4386 -- not the name of an entity.
4388 elsif not Is_Entity_Name (P) then
4392 -- Otherwise get prefix entity
4395 P_Entity := Entity (P);
4398 -- At this stage P_Entity is the entity to which the attribute
4399 -- is to be applied. This is usually simply the entity of the
4400 -- prefix, except in some cases of attributes for objects, where
4401 -- as described above, we apply the attribute to the object type.
4403 -- First foldable possibility is a scalar or array type (RM 4.9(7))
4404 -- that is not generic (generic types are eliminated by RM 4.9(25)).
4405 -- Note we allow non-static non-generic types at this stage as further
4408 if Is_Type (P_Entity)
4409 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
4410 and then (not Is_Generic_Type (P_Entity))
4414 -- Second foldable possibility is an array object (RM 4.9(8))
4416 elsif (Ekind (P_Entity) = E_Variable
4418 Ekind (P_Entity) = E_Constant)
4419 and then Is_Array_Type (Etype (P_Entity))
4420 and then (not Is_Generic_Type (Etype (P_Entity)))
4422 P_Type := Etype (P_Entity);
4424 -- If the entity is an array constant with an unconstrained
4425 -- nominal subtype then get the type from the initial value.
4426 -- If the value has been expanded into assignments, the expression
4427 -- is not present and the attribute reference remains dynamic.
4428 -- We could do better here and retrieve the type ???
4430 if Ekind (P_Entity) = E_Constant
4431 and then not Is_Constrained (P_Type)
4433 if No (Constant_Value (P_Entity)) then
4436 P_Type := Etype (Constant_Value (P_Entity));
4440 -- Definite must be folded if the prefix is not a generic type,
4441 -- that is to say if we are within an instantiation. Same processing
4442 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
4443 -- and Unconstrained_Array.
4445 elsif (Id = Attribute_Definite
4447 Id = Attribute_Has_Access_Values
4449 Id = Attribute_Has_Discriminants
4451 Id = Attribute_Type_Class
4453 Id = Attribute_Unconstrained_Array)
4454 and then not Is_Generic_Type (P_Entity)
4458 -- We can fold 'Size applied to a type if the size is known
4459 -- (as happens for a size from an attribute definition clause).
4460 -- At this stage, this can happen only for types (e.g. record
4461 -- types) for which the size is always non-static. We exclude
4462 -- generic types from consideration (since they have bogus
4463 -- sizes set within templates).
4465 elsif Id = Attribute_Size
4466 and then Is_Type (P_Entity)
4467 and then (not Is_Generic_Type (P_Entity))
4468 and then Known_Static_RM_Size (P_Entity)
4470 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
4473 -- We can fold 'Alignment applied to a type if the alignment is known
4474 -- (as happens for an alignment from an attribute definition clause).
4475 -- At this stage, this can happen only for types (e.g. record
4476 -- types) for which the size is always non-static. We exclude
4477 -- generic types from consideration (since they have bogus
4478 -- sizes set within templates).
4480 elsif Id = Attribute_Alignment
4481 and then Is_Type (P_Entity)
4482 and then (not Is_Generic_Type (P_Entity))
4483 and then Known_Alignment (P_Entity)
4485 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
4488 -- If this is an access attribute that is known to fail accessibility
4489 -- check, rewrite accordingly.
4491 elsif Attribute_Name (N) = Name_Access
4492 and then Raises_Constraint_Error (N)
4495 Make_Raise_Program_Error (Loc,
4496 Reason => PE_Accessibility_Check_Failed));
4497 Set_Etype (N, C_Type);
4500 -- No other cases are foldable (they certainly aren't static, and at
4501 -- the moment we don't try to fold any cases other than these three).
4508 -- If either attribute or the prefix is Any_Type, then propagate
4509 -- Any_Type to the result and don't do anything else at all.
4511 if P_Type = Any_Type
4512 or else (Present (E1) and then Etype (E1) = Any_Type)
4513 or else (Present (E2) and then Etype (E2) = Any_Type)
4515 Set_Etype (N, Any_Type);
4519 -- Scalar subtype case. We have not yet enforced the static requirement
4520 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
4521 -- of non-static attribute references (e.g. S'Digits for a non-static
4522 -- floating-point type, which we can compute at compile time).
4524 -- Note: this folding of non-static attributes is not simply a case of
4525 -- optimization. For many of the attributes affected, Gigi cannot handle
4526 -- the attribute and depends on the front end having folded them away.
4528 -- Note: although we don't require staticness at this stage, we do set
4529 -- the Static variable to record the staticness, for easy reference by
4530 -- those attributes where it matters (e.g. Succ and Pred), and also to
4531 -- be used to ensure that non-static folded things are not marked as
4532 -- being static (a check that is done right at the end).
4534 P_Root_Type := Root_Type (P_Type);
4535 P_Base_Type := Base_Type (P_Type);
4537 -- If the root type or base type is generic, then we cannot fold. This
4538 -- test is needed because subtypes of generic types are not always
4539 -- marked as being generic themselves (which seems odd???)
4541 if Is_Generic_Type (P_Root_Type)
4542 or else Is_Generic_Type (P_Base_Type)
4547 if Is_Scalar_Type (P_Type) then
4548 Static := Is_OK_Static_Subtype (P_Type);
4550 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
4551 -- since we can't do anything with unconstrained arrays. In addition,
4552 -- only the First, Last and Length attributes are possibly static.
4553 -- In addition Component_Size is possibly foldable, even though it
4554 -- can never be static.
4556 -- Definite, Has_Access_Values, Has_Discriminants, Type_Class, and
4557 -- Unconstrained_Array are again exceptions, because they apply as
4558 -- well to unconstrained types.
4560 elsif Id = Attribute_Definite
4562 Id = Attribute_Has_Access_Values
4564 Id = Attribute_Has_Discriminants
4566 Id = Attribute_Type_Class
4568 Id = Attribute_Unconstrained_Array
4573 if not Is_Constrained (P_Type)
4574 or else (Id /= Attribute_Component_Size and then
4575 Id /= Attribute_First and then
4576 Id /= Attribute_Last and then
4577 Id /= Attribute_Length)
4583 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
4584 -- scalar case, we hold off on enforcing staticness, since there are
4585 -- cases which we can fold at compile time even though they are not
4586 -- static (e.g. 'Length applied to a static index, even though other
4587 -- non-static indexes make the array type non-static). This is only
4588 -- an optimization, but it falls out essentially free, so why not.
4589 -- Again we compute the variable Static for easy reference later
4590 -- (note that no array attributes are static in Ada 83).
4592 Static := Ada_Version >= Ada_95;
4598 N := First_Index (P_Type);
4599 while Present (N) loop
4600 Static := Static and then Is_Static_Subtype (Etype (N));
4602 -- If however the index type is generic, attributes cannot
4605 if Is_Generic_Type (Etype (N))
4606 and then Id /= Attribute_Component_Size
4616 -- Check any expressions that are present. Note that these expressions,
4617 -- depending on the particular attribute type, are either part of the
4618 -- attribute designator, or they are arguments in a case where the
4619 -- attribute reference returns a function. In the latter case, the
4620 -- rule in (RM 4.9(22)) applies and in particular requires the type
4621 -- of the expressions to be scalar in order for the attribute to be
4622 -- considered to be static.
4629 while Present (E) loop
4631 -- If expression is not static, then the attribute reference
4632 -- result certainly cannot be static.
4634 if not Is_Static_Expression (E) then
4638 -- If the result is not known at compile time, or is not of
4639 -- a scalar type, then the result is definitely not static,
4640 -- so we can quit now.
4642 if not Compile_Time_Known_Value (E)
4643 or else not Is_Scalar_Type (Etype (E))
4645 -- An odd special case, if this is a Pos attribute, this
4646 -- is where we need to apply a range check since it does
4647 -- not get done anywhere else.
4649 if Id = Attribute_Pos then
4650 if Is_Integer_Type (Etype (E)) then
4651 Apply_Range_Check (E, Etype (N));
4658 -- If the expression raises a constraint error, then so does
4659 -- the attribute reference. We keep going in this case because
4660 -- we are still interested in whether the attribute reference
4661 -- is static even if it is not static.
4663 elsif Raises_Constraint_Error (E) then
4664 Set_Raises_Constraint_Error (N);
4670 if Raises_Constraint_Error (Prefix (N)) then
4675 -- Deal with the case of a static attribute reference that raises
4676 -- constraint error. The Raises_Constraint_Error flag will already
4677 -- have been set, and the Static flag shows whether the attribute
4678 -- reference is static. In any case we certainly can't fold such an
4679 -- attribute reference.
4681 -- Note that the rewriting of the attribute node with the constraint
4682 -- error node is essential in this case, because otherwise Gigi might
4683 -- blow up on one of the attributes it never expects to see.
4685 -- The constraint_error node must have the type imposed by the context,
4686 -- to avoid spurious errors in the enclosing expression.
4688 if Raises_Constraint_Error (N) then
4690 Make_Raise_Constraint_Error (Sloc (N),
4691 Reason => CE_Range_Check_Failed);
4692 Set_Etype (CE_Node, Etype (N));
4693 Set_Raises_Constraint_Error (CE_Node);
4695 Rewrite (N, Relocate_Node (CE_Node));
4696 Set_Is_Static_Expression (N, Static);
4700 -- At this point we have a potentially foldable attribute reference.
4701 -- If Static is set, then the attribute reference definitely obeys
4702 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
4703 -- folded. If Static is not set, then the attribute may or may not
4704 -- be foldable, and the individual attribute processing routines
4705 -- test Static as required in cases where it makes a difference.
4707 -- In the case where Static is not set, we do know that all the
4708 -- expressions present are at least known at compile time (we
4709 -- assumed above that if this was not the case, then there was
4710 -- no hope of static evaluation). However, we did not require
4711 -- that the bounds of the prefix type be compile time known,
4712 -- let alone static). That's because there are many attributes
4713 -- that can be computed at compile time on non-static subtypes,
4714 -- even though such references are not static expressions.
4722 when Attribute_Adjacent =>
4725 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
4731 when Attribute_Aft =>
4732 Fold_Uint (N, UI_From_Int (Aft_Value), True);
4738 when Attribute_Alignment => Alignment_Block : declare
4739 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
4742 -- Fold if alignment is set and not otherwise
4744 if Known_Alignment (P_TypeA) then
4745 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
4747 end Alignment_Block;
4753 -- Can only be folded in No_Ast_Handler case
4755 when Attribute_AST_Entry =>
4756 if not Is_AST_Entry (P_Entity) then
4758 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
4767 -- Bit can never be folded
4769 when Attribute_Bit =>
4776 -- Body_version can never be static
4778 when Attribute_Body_Version =>
4785 when Attribute_Ceiling =>
4787 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
4789 --------------------
4790 -- Component_Size --
4791 --------------------
4793 when Attribute_Component_Size =>
4794 if Known_Static_Component_Size (P_Type) then
4795 Fold_Uint (N, Component_Size (P_Type), False);
4802 when Attribute_Compose =>
4805 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
4812 -- Constrained is never folded for now, there may be cases that
4813 -- could be handled at compile time. to be looked at later.
4815 when Attribute_Constrained =>
4822 when Attribute_Copy_Sign =>
4825 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
4831 when Attribute_Delta =>
4832 Fold_Ureal (N, Delta_Value (P_Type), True);
4838 when Attribute_Definite =>
4839 Rewrite (N, New_Occurrence_Of (
4840 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
4841 Analyze_And_Resolve (N, Standard_Boolean);
4847 when Attribute_Denorm =>
4849 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
4855 when Attribute_Digits =>
4856 Fold_Uint (N, Digits_Value (P_Type), True);
4862 when Attribute_Emax =>
4864 -- Ada 83 attribute is defined as (RM83 3.5.8)
4866 -- T'Emax = 4 * T'Mantissa
4868 Fold_Uint (N, 4 * Mantissa, True);
4874 when Attribute_Enum_Rep =>
4876 -- For an enumeration type with a non-standard representation
4877 -- use the Enumeration_Rep field of the proper constant. Note
4878 -- that this would not work for types Character/Wide_Character,
4879 -- since no real entities are created for the enumeration
4880 -- literals, but that does not matter since these two types
4881 -- do not have non-standard representations anyway.
4883 if Is_Enumeration_Type (P_Type)
4884 and then Has_Non_Standard_Rep (P_Type)
4886 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
4888 -- For enumeration types with standard representations and all
4889 -- other cases (i.e. all integer and modular types), Enum_Rep
4890 -- is equivalent to Pos.
4893 Fold_Uint (N, Expr_Value (E1), Static);
4900 when Attribute_Epsilon =>
4902 -- Ada 83 attribute is defined as (RM83 3.5.8)
4904 -- T'Epsilon = 2.0**(1 - T'Mantissa)
4906 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
4912 when Attribute_Exponent =>
4914 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
4920 when Attribute_First => First_Attr :
4924 if Compile_Time_Known_Value (Lo_Bound) then
4925 if Is_Real_Type (P_Type) then
4926 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
4928 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
4937 when Attribute_Fixed_Value =>
4944 when Attribute_Floor =>
4946 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
4952 when Attribute_Fore =>
4953 if Compile_Time_Known_Bounds (P_Type) then
4954 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
4961 when Attribute_Fraction =>
4963 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
4965 -----------------------
4966 -- Has_Access_Values --
4967 -----------------------
4969 when Attribute_Has_Access_Values =>
4970 Rewrite (N, New_Occurrence_Of
4971 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
4972 Analyze_And_Resolve (N, Standard_Boolean);
4974 -----------------------
4975 -- Has_Discriminants --
4976 -----------------------
4978 when Attribute_Has_Discriminants =>
4979 Rewrite (N, New_Occurrence_Of (
4980 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
4981 Analyze_And_Resolve (N, Standard_Boolean);
4987 when Attribute_Identity =>
4994 -- Image is a scalar attribute, but is never static, because it is
4995 -- not a static function (having a non-scalar argument (RM 4.9(22))
4997 when Attribute_Image =>
5004 -- Img is a scalar attribute, but is never static, because it is
5005 -- not a static function (having a non-scalar argument (RM 4.9(22))
5007 when Attribute_Img =>
5014 when Attribute_Integer_Value =>
5021 when Attribute_Large =>
5023 -- For fixed-point, we use the identity:
5025 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
5027 if Is_Fixed_Point_Type (P_Type) then
5029 Make_Op_Multiply (Loc,
5031 Make_Op_Subtract (Loc,
5035 Make_Real_Literal (Loc, Ureal_2),
5037 Make_Attribute_Reference (Loc,
5039 Attribute_Name => Name_Mantissa)),
5040 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
5043 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
5045 Analyze_And_Resolve (N, C_Type);
5047 -- Floating-point (Ada 83 compatibility)
5050 -- Ada 83 attribute is defined as (RM83 3.5.8)
5052 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
5056 -- T'Emax = 4 * T'Mantissa
5059 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
5067 when Attribute_Last => Last :
5071 if Compile_Time_Known_Value (Hi_Bound) then
5072 if Is_Real_Type (P_Type) then
5073 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
5075 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
5084 when Attribute_Leading_Part =>
5086 Eval_Fat.Leading_Part
5087 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
5093 when Attribute_Length => Length : declare
5097 -- In the case of a generic index type, the bounds may
5098 -- appear static but the computation is not meaningful,
5099 -- and may generate a spurious warning.
5101 Ind := First_Index (P_Type);
5103 while Present (Ind) loop
5104 if Is_Generic_Type (Etype (Ind)) then
5113 if Compile_Time_Known_Value (Lo_Bound)
5114 and then Compile_Time_Known_Value (Hi_Bound)
5117 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
5126 when Attribute_Machine =>
5129 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
5136 when Attribute_Machine_Emax =>
5137 Float_Attribute_Universal_Integer (
5145 AAMPL_Machine_Emax);
5151 when Attribute_Machine_Emin =>
5152 Float_Attribute_Universal_Integer (
5160 AAMPL_Machine_Emin);
5162 ----------------------
5163 -- Machine_Mantissa --
5164 ----------------------
5166 when Attribute_Machine_Mantissa =>
5167 Float_Attribute_Universal_Integer (
5168 IEEES_Machine_Mantissa,
5169 IEEEL_Machine_Mantissa,
5170 IEEEX_Machine_Mantissa,
5171 VAXFF_Machine_Mantissa,
5172 VAXDF_Machine_Mantissa,
5173 VAXGF_Machine_Mantissa,
5174 AAMPS_Machine_Mantissa,
5175 AAMPL_Machine_Mantissa);
5177 -----------------------
5178 -- Machine_Overflows --
5179 -----------------------
5181 when Attribute_Machine_Overflows =>
5183 -- Always true for fixed-point
5185 if Is_Fixed_Point_Type (P_Type) then
5186 Fold_Uint (N, True_Value, True);
5188 -- Floating point case
5192 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
5200 when Attribute_Machine_Radix =>
5201 if Is_Fixed_Point_Type (P_Type) then
5202 if Is_Decimal_Fixed_Point_Type (P_Type)
5203 and then Machine_Radix_10 (P_Type)
5205 Fold_Uint (N, Uint_10, True);
5207 Fold_Uint (N, Uint_2, True);
5210 -- All floating-point type always have radix 2
5213 Fold_Uint (N, Uint_2, True);
5216 --------------------
5217 -- Machine_Rounds --
5218 --------------------
5220 when Attribute_Machine_Rounds =>
5222 -- Always False for fixed-point
5224 if Is_Fixed_Point_Type (P_Type) then
5225 Fold_Uint (N, False_Value, True);
5227 -- Else yield proper floating-point result
5231 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
5238 -- Note: Machine_Size is identical to Object_Size
5240 when Attribute_Machine_Size => Machine_Size : declare
5241 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5244 if Known_Esize (P_TypeA) then
5245 Fold_Uint (N, Esize (P_TypeA), True);
5253 when Attribute_Mantissa =>
5255 -- Fixed-point mantissa
5257 if Is_Fixed_Point_Type (P_Type) then
5259 -- Compile time foldable case
5261 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5263 Compile_Time_Known_Value (Type_High_Bound (P_Type))
5265 -- The calculation of the obsolete Ada 83 attribute Mantissa
5266 -- is annoying, because of AI00143, quoted here:
5268 -- !question 84-01-10
5270 -- Consider the model numbers for F:
5272 -- type F is delta 1.0 range -7.0 .. 8.0;
5274 -- The wording requires that F'MANTISSA be the SMALLEST
5275 -- integer number for which each bound of the specified
5276 -- range is either a model number or lies at most small
5277 -- distant from a model number. This means F'MANTISSA
5278 -- is required to be 3 since the range -7.0 .. 7.0 fits
5279 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
5280 -- number, namely, 7. Is this analysis correct? Note that
5281 -- this implies the upper bound of the range is not
5282 -- represented as a model number.
5284 -- !response 84-03-17
5286 -- The analysis is correct. The upper and lower bounds for
5287 -- a fixed point type can lie outside the range of model
5298 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
5299 UBound := Expr_Value_R (Type_High_Bound (P_Type));
5300 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
5301 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
5303 -- If the Bound is exactly a model number, i.e. a multiple
5304 -- of Small, then we back it off by one to get the integer
5305 -- value that must be representable.
5307 if Small_Value (P_Type) * Max_Man = Bound then
5308 Max_Man := Max_Man - 1;
5311 -- Now find corresponding size = Mantissa value
5314 while 2 ** Siz < Max_Man loop
5318 Fold_Uint (N, Siz, True);
5322 -- The case of dynamic bounds cannot be evaluated at compile
5323 -- time. Instead we use a runtime routine (see Exp_Attr).
5328 -- Floating-point Mantissa
5331 Fold_Uint (N, Mantissa, True);
5338 when Attribute_Max => Max :
5340 if Is_Real_Type (P_Type) then
5342 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5344 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
5348 ----------------------------------
5349 -- Max_Size_In_Storage_Elements --
5350 ----------------------------------
5352 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
5353 -- Storage_Unit boundary. We can fold any cases for which the size
5354 -- is known by the front end.
5356 when Attribute_Max_Size_In_Storage_Elements =>
5357 if Known_Esize (P_Type) then
5359 (Esize (P_Type) + System_Storage_Unit - 1) /
5360 System_Storage_Unit,
5364 --------------------
5365 -- Mechanism_Code --
5366 --------------------
5368 when Attribute_Mechanism_Code =>
5372 Mech : Mechanism_Type;
5376 Mech := Mechanism (P_Entity);
5379 Val := UI_To_Int (Expr_Value (E1));
5381 Formal := First_Formal (P_Entity);
5382 for J in 1 .. Val - 1 loop
5383 Next_Formal (Formal);
5385 Mech := Mechanism (Formal);
5389 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
5397 when Attribute_Min => Min :
5399 if Is_Real_Type (P_Type) then
5401 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5403 Fold_Uint (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
5411 when Attribute_Model =>
5413 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
5419 when Attribute_Model_Emin =>
5420 Float_Attribute_Universal_Integer (
5434 when Attribute_Model_Epsilon =>
5435 Float_Attribute_Universal_Real (
5436 IEEES_Model_Epsilon'Universal_Literal_String,
5437 IEEEL_Model_Epsilon'Universal_Literal_String,
5438 IEEEX_Model_Epsilon'Universal_Literal_String,
5439 VAXFF_Model_Epsilon'Universal_Literal_String,
5440 VAXDF_Model_Epsilon'Universal_Literal_String,
5441 VAXGF_Model_Epsilon'Universal_Literal_String,
5442 AAMPS_Model_Epsilon'Universal_Literal_String,
5443 AAMPL_Model_Epsilon'Universal_Literal_String);
5445 --------------------
5446 -- Model_Mantissa --
5447 --------------------
5449 when Attribute_Model_Mantissa =>
5450 Float_Attribute_Universal_Integer (
5451 IEEES_Model_Mantissa,
5452 IEEEL_Model_Mantissa,
5453 IEEEX_Model_Mantissa,
5454 VAXFF_Model_Mantissa,
5455 VAXDF_Model_Mantissa,
5456 VAXGF_Model_Mantissa,
5457 AAMPS_Model_Mantissa,
5458 AAMPL_Model_Mantissa);
5464 when Attribute_Model_Small =>
5465 Float_Attribute_Universal_Real (
5466 IEEES_Model_Small'Universal_Literal_String,
5467 IEEEL_Model_Small'Universal_Literal_String,
5468 IEEEX_Model_Small'Universal_Literal_String,
5469 VAXFF_Model_Small'Universal_Literal_String,
5470 VAXDF_Model_Small'Universal_Literal_String,
5471 VAXGF_Model_Small'Universal_Literal_String,
5472 AAMPS_Model_Small'Universal_Literal_String,
5473 AAMPL_Model_Small'Universal_Literal_String);
5479 when Attribute_Modulus =>
5480 Fold_Uint (N, Modulus (P_Type), True);
5482 --------------------
5483 -- Null_Parameter --
5484 --------------------
5486 -- Cannot fold, we know the value sort of, but the whole point is
5487 -- that there is no way to talk about this imaginary value except
5488 -- by using the attribute, so we leave it the way it is.
5490 when Attribute_Null_Parameter =>
5497 -- The Object_Size attribute for a type returns the Esize of the
5498 -- type and can be folded if this value is known.
5500 when Attribute_Object_Size => Object_Size : declare
5501 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5504 if Known_Esize (P_TypeA) then
5505 Fold_Uint (N, Esize (P_TypeA), True);
5509 -------------------------
5510 -- Passed_By_Reference --
5511 -------------------------
5513 -- Scalar types are never passed by reference
5515 when Attribute_Passed_By_Reference =>
5516 Fold_Uint (N, False_Value, True);
5522 when Attribute_Pos =>
5523 Fold_Uint (N, Expr_Value (E1), True);
5529 when Attribute_Pred => Pred :
5531 -- Floating-point case
5533 if Is_Floating_Point_Type (P_Type) then
5535 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
5539 elsif Is_Fixed_Point_Type (P_Type) then
5541 Expr_Value_R (E1) - Small_Value (P_Type), True);
5543 -- Modular integer case (wraps)
5545 elsif Is_Modular_Integer_Type (P_Type) then
5546 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
5548 -- Other scalar cases
5551 pragma Assert (Is_Scalar_Type (P_Type));
5553 if Is_Enumeration_Type (P_Type)
5554 and then Expr_Value (E1) =
5555 Expr_Value (Type_Low_Bound (P_Base_Type))
5557 Apply_Compile_Time_Constraint_Error
5558 (N, "Pred of `&''First`",
5559 CE_Overflow_Check_Failed,
5561 Warn => not Static);
5567 Fold_Uint (N, Expr_Value (E1) - 1, Static);
5575 -- No processing required, because by this stage, Range has been
5576 -- replaced by First .. Last, so this branch can never be taken.
5578 when Attribute_Range =>
5579 raise Program_Error;
5585 when Attribute_Range_Length =>
5588 if Compile_Time_Known_Value (Hi_Bound)
5589 and then Compile_Time_Known_Value (Lo_Bound)
5593 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
5601 when Attribute_Remainder =>
5604 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
5611 when Attribute_Round => Round :
5617 -- First we get the (exact result) in units of small
5619 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
5621 -- Now round that exactly to an integer
5623 Si := UR_To_Uint (Sr);
5625 -- Finally the result is obtained by converting back to real
5627 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
5634 when Attribute_Rounding =>
5636 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
5642 when Attribute_Safe_Emax =>
5643 Float_Attribute_Universal_Integer (
5657 when Attribute_Safe_First =>
5658 Float_Attribute_Universal_Real (
5659 IEEES_Safe_First'Universal_Literal_String,
5660 IEEEL_Safe_First'Universal_Literal_String,
5661 IEEEX_Safe_First'Universal_Literal_String,
5662 VAXFF_Safe_First'Universal_Literal_String,
5663 VAXDF_Safe_First'Universal_Literal_String,
5664 VAXGF_Safe_First'Universal_Literal_String,
5665 AAMPS_Safe_First'Universal_Literal_String,
5666 AAMPL_Safe_First'Universal_Literal_String);
5672 when Attribute_Safe_Large =>
5673 if Is_Fixed_Point_Type (P_Type) then
5675 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
5677 Float_Attribute_Universal_Real (
5678 IEEES_Safe_Large'Universal_Literal_String,
5679 IEEEL_Safe_Large'Universal_Literal_String,
5680 IEEEX_Safe_Large'Universal_Literal_String,
5681 VAXFF_Safe_Large'Universal_Literal_String,
5682 VAXDF_Safe_Large'Universal_Literal_String,
5683 VAXGF_Safe_Large'Universal_Literal_String,
5684 AAMPS_Safe_Large'Universal_Literal_String,
5685 AAMPL_Safe_Large'Universal_Literal_String);
5692 when Attribute_Safe_Last =>
5693 Float_Attribute_Universal_Real (
5694 IEEES_Safe_Last'Universal_Literal_String,
5695 IEEEL_Safe_Last'Universal_Literal_String,
5696 IEEEX_Safe_Last'Universal_Literal_String,
5697 VAXFF_Safe_Last'Universal_Literal_String,
5698 VAXDF_Safe_Last'Universal_Literal_String,
5699 VAXGF_Safe_Last'Universal_Literal_String,
5700 AAMPS_Safe_Last'Universal_Literal_String,
5701 AAMPL_Safe_Last'Universal_Literal_String);
5707 when Attribute_Safe_Small =>
5709 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
5710 -- for fixed-point, since is the same as Small, but we implement
5711 -- it for backwards compatibility.
5713 if Is_Fixed_Point_Type (P_Type) then
5714 Fold_Ureal (N, Small_Value (P_Type), Static);
5716 -- Ada 83 Safe_Small for floating-point cases
5719 Float_Attribute_Universal_Real (
5720 IEEES_Safe_Small'Universal_Literal_String,
5721 IEEEL_Safe_Small'Universal_Literal_String,
5722 IEEEX_Safe_Small'Universal_Literal_String,
5723 VAXFF_Safe_Small'Universal_Literal_String,
5724 VAXDF_Safe_Small'Universal_Literal_String,
5725 VAXGF_Safe_Small'Universal_Literal_String,
5726 AAMPS_Safe_Small'Universal_Literal_String,
5727 AAMPL_Safe_Small'Universal_Literal_String);
5734 when Attribute_Scale =>
5735 Fold_Uint (N, Scale_Value (P_Type), True);
5741 when Attribute_Scaling =>
5744 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
5750 when Attribute_Signed_Zeros =>
5752 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
5758 -- Size attribute returns the RM size. All scalar types can be folded,
5759 -- as well as any types for which the size is known by the front end,
5760 -- including any type for which a size attribute is specified.
5762 when Attribute_Size | Attribute_VADS_Size => Size : declare
5763 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5766 if RM_Size (P_TypeA) /= Uint_0 then
5770 if Id = Attribute_VADS_Size or else Use_VADS_Size then
5772 S : constant Node_Id := Size_Clause (P_TypeA);
5775 -- If a size clause applies, then use the size from it.
5776 -- This is one of the rare cases where we can use the
5777 -- Size_Clause field for a subtype when Has_Size_Clause
5778 -- is False. Consider:
5780 -- type x is range 1 .. 64; g
5781 -- for x'size use 12;
5782 -- subtype y is x range 0 .. 3;
5784 -- Here y has a size clause inherited from x, but normally
5785 -- it does not apply, and y'size is 2. However, y'VADS_Size
5786 -- is indeed 12 and not 2.
5789 and then Is_OK_Static_Expression (Expression (S))
5791 Fold_Uint (N, Expr_Value (Expression (S)), True);
5793 -- If no size is specified, then we simply use the object
5794 -- size in the VADS_Size case (e.g. Natural'Size is equal
5795 -- to Integer'Size, not one less).
5798 Fold_Uint (N, Esize (P_TypeA), True);
5802 -- Normal case (Size) in which case we want the RM_Size
5807 Static and then Is_Discrete_Type (P_TypeA));
5816 when Attribute_Small =>
5818 -- The floating-point case is present only for Ada 83 compatability.
5819 -- Note that strictly this is an illegal addition, since we are
5820 -- extending an Ada 95 defined attribute, but we anticipate an
5821 -- ARG ruling that will permit this.
5823 if Is_Floating_Point_Type (P_Type) then
5825 -- Ada 83 attribute is defined as (RM83 3.5.8)
5827 -- T'Small = 2.0**(-T'Emax - 1)
5831 -- T'Emax = 4 * T'Mantissa
5833 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
5835 -- Normal Ada 95 fixed-point case
5838 Fold_Ureal (N, Small_Value (P_Type), True);
5845 when Attribute_Succ => Succ :
5847 -- Floating-point case
5849 if Is_Floating_Point_Type (P_Type) then
5851 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
5855 elsif Is_Fixed_Point_Type (P_Type) then
5857 Expr_Value_R (E1) + Small_Value (P_Type), Static);
5859 -- Modular integer case (wraps)
5861 elsif Is_Modular_Integer_Type (P_Type) then
5862 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
5864 -- Other scalar cases
5867 pragma Assert (Is_Scalar_Type (P_Type));
5869 if Is_Enumeration_Type (P_Type)
5870 and then Expr_Value (E1) =
5871 Expr_Value (Type_High_Bound (P_Base_Type))
5873 Apply_Compile_Time_Constraint_Error
5874 (N, "Succ of `&''Last`",
5875 CE_Overflow_Check_Failed,
5877 Warn => not Static);
5882 Fold_Uint (N, Expr_Value (E1) + 1, Static);
5891 when Attribute_Truncation =>
5893 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
5899 when Attribute_Type_Class => Type_Class : declare
5900 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
5904 if Is_Descendent_Of_Address (Typ) then
5905 Id := RE_Type_Class_Address;
5907 elsif Is_Enumeration_Type (Typ) then
5908 Id := RE_Type_Class_Enumeration;
5910 elsif Is_Integer_Type (Typ) then
5911 Id := RE_Type_Class_Integer;
5913 elsif Is_Fixed_Point_Type (Typ) then
5914 Id := RE_Type_Class_Fixed_Point;
5916 elsif Is_Floating_Point_Type (Typ) then
5917 Id := RE_Type_Class_Floating_Point;
5919 elsif Is_Array_Type (Typ) then
5920 Id := RE_Type_Class_Array;
5922 elsif Is_Record_Type (Typ) then
5923 Id := RE_Type_Class_Record;
5925 elsif Is_Access_Type (Typ) then
5926 Id := RE_Type_Class_Access;
5928 elsif Is_Enumeration_Type (Typ) then
5929 Id := RE_Type_Class_Enumeration;
5931 elsif Is_Task_Type (Typ) then
5932 Id := RE_Type_Class_Task;
5934 -- We treat protected types like task types. It would make more
5935 -- sense to have another enumeration value, but after all the
5936 -- whole point of this feature is to be exactly DEC compatible,
5937 -- and changing the type Type_Clas would not meet this requirement.
5939 elsif Is_Protected_Type (Typ) then
5940 Id := RE_Type_Class_Task;
5942 -- Not clear if there are any other possibilities, but if there
5943 -- are, then we will treat them as the address case.
5946 Id := RE_Type_Class_Address;
5949 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
5953 -----------------------
5954 -- Unbiased_Rounding --
5955 -----------------------
5957 when Attribute_Unbiased_Rounding =>
5959 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
5962 -------------------------
5963 -- Unconstrained_Array --
5964 -------------------------
5966 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
5967 Typ : constant Entity_Id := Underlying_Type (P_Type);
5970 Rewrite (N, New_Occurrence_Of (
5972 Is_Array_Type (P_Type)
5973 and then not Is_Constrained (Typ)), Loc));
5975 -- Analyze and resolve as boolean, note that this attribute is
5976 -- a static attribute in GNAT.
5978 Analyze_And_Resolve (N, Standard_Boolean);
5980 end Unconstrained_Array;
5986 -- Processing is shared with Size
5992 when Attribute_Val => Val :
5994 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
5996 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
5998 Apply_Compile_Time_Constraint_Error
5999 (N, "Val expression out of range",
6000 CE_Range_Check_Failed,
6001 Warn => not Static);
6007 Fold_Uint (N, Expr_Value (E1), Static);
6015 -- The Value_Size attribute for a type returns the RM size of the
6016 -- type. This an always be folded for scalar types, and can also
6017 -- be folded for non-scalar types if the size is set.
6019 when Attribute_Value_Size => Value_Size : declare
6020 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6023 if RM_Size (P_TypeA) /= Uint_0 then
6024 Fold_Uint (N, RM_Size (P_TypeA), True);
6033 -- Version can never be static
6035 when Attribute_Version =>
6042 -- Wide_Image is a scalar attribute, but is never static, because it
6043 -- is not a static function (having a non-scalar argument (RM 4.9(22))
6045 when Attribute_Wide_Image =>
6052 -- Processing for Wide_Width is combined with Width
6058 -- This processing also handles the case of Wide_Width
6060 when Attribute_Width | Attribute_Wide_Width => Width :
6062 if Compile_Time_Known_Bounds (P_Type) then
6064 -- Floating-point types
6066 if Is_Floating_Point_Type (P_Type) then
6068 -- Width is zero for a null range (RM 3.5 (38))
6070 if Expr_Value_R (Type_High_Bound (P_Type)) <
6071 Expr_Value_R (Type_Low_Bound (P_Type))
6073 Fold_Uint (N, Uint_0, True);
6076 -- For floating-point, we have +N.dddE+nnn where length
6077 -- of ddd is determined by type'Digits - 1, but is one
6078 -- if Digits is one (RM 3.5 (33)).
6080 -- nnn is set to 2 for Short_Float and Float (32 bit
6081 -- floats), and 3 for Long_Float and Long_Long_Float.
6082 -- This is not quite right, but is good enough.
6086 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
6089 if Esize (P_Type) <= 32 then
6095 Fold_Uint (N, UI_From_Int (Len), True);
6099 -- Fixed-point types
6101 elsif Is_Fixed_Point_Type (P_Type) then
6103 -- Width is zero for a null range (RM 3.5 (38))
6105 if Expr_Value (Type_High_Bound (P_Type)) <
6106 Expr_Value (Type_Low_Bound (P_Type))
6108 Fold_Uint (N, Uint_0, True);
6110 -- The non-null case depends on the specific real type
6113 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
6116 (N, UI_From_Int (Fore_Value + 1 + Aft_Value), True);
6123 R : constant Entity_Id := Root_Type (P_Type);
6124 Lo : constant Uint :=
6125 Expr_Value (Type_Low_Bound (P_Type));
6126 Hi : constant Uint :=
6127 Expr_Value (Type_High_Bound (P_Type));
6140 -- Width for types derived from Standard.Character
6141 -- and Standard.Wide_Character.
6143 elsif R = Standard_Character
6144 or else R = Standard_Wide_Character
6148 -- Set W larger if needed
6150 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
6152 -- Assume all wide-character escape sequences are
6153 -- same length, so we can quit when we reach one.
6156 if Id = Attribute_Wide_Width then
6157 W := Int'Max (W, 3);
6160 W := Int'Max (W, Length_Wide);
6165 C := Character'Val (J);
6167 -- Test for all cases where Character'Image
6168 -- yields an image that is longer than three
6169 -- characters. First the cases of Reserved_xxx
6170 -- names (length = 12).
6173 when Reserved_128 | Reserved_129 |
6174 Reserved_132 | Reserved_153
6178 when BS | HT | LF | VT | FF | CR |
6179 SO | SI | EM | FS | GS | RS |
6180 US | RI | MW | ST | PM
6184 when NUL | SOH | STX | ETX | EOT |
6185 ENQ | ACK | BEL | DLE | DC1 |
6186 DC2 | DC3 | DC4 | NAK | SYN |
6187 ETB | CAN | SUB | ESC | DEL |
6188 BPH | NBH | NEL | SSA | ESA |
6189 HTS | HTJ | VTS | PLD | PLU |
6190 SS2 | SS3 | DCS | PU1 | PU2 |
6191 STS | CCH | SPA | EPA | SOS |
6192 SCI | CSI | OSC | APC
6196 when Space .. Tilde |
6197 No_Break_Space .. LC_Y_Diaeresis
6202 W := Int'Max (W, Wt);
6206 -- Width for types derived from Standard.Boolean
6208 elsif R = Standard_Boolean then
6215 -- Width for integer types
6217 elsif Is_Integer_Type (P_Type) then
6218 T := UI_Max (abs Lo, abs Hi);
6226 -- Only remaining possibility is user declared enum type
6229 pragma Assert (Is_Enumeration_Type (P_Type));
6232 L := First_Literal (P_Type);
6234 while Present (L) loop
6236 -- Only pay attention to in range characters
6238 if Lo <= Enumeration_Pos (L)
6239 and then Enumeration_Pos (L) <= Hi
6241 -- For Width case, use decoded name
6243 if Id = Attribute_Width then
6244 Get_Decoded_Name_String (Chars (L));
6245 Wt := Nat (Name_Len);
6247 -- For Wide_Width, use encoded name, and then
6248 -- adjust for the encoding.
6251 Get_Name_String (Chars (L));
6253 -- Character literals are always of length 3
6255 if Name_Buffer (1) = 'Q' then
6258 -- Otherwise loop to adjust for upper/wide chars
6261 Wt := Nat (Name_Len);
6263 for J in 1 .. Name_Len loop
6264 if Name_Buffer (J) = 'U' then
6266 elsif Name_Buffer (J) = 'W' then
6273 W := Int'Max (W, Wt);
6280 Fold_Uint (N, UI_From_Int (W), True);
6286 -- The following attributes can never be folded, and furthermore we
6287 -- should not even have entered the case statement for any of these.
6288 -- Note that in some cases, the values have already been folded as
6289 -- a result of the processing in Analyze_Attribute.
6291 when Attribute_Abort_Signal |
6294 Attribute_Address_Size |
6295 Attribute_Asm_Input |
6296 Attribute_Asm_Output |
6298 Attribute_Bit_Order |
6299 Attribute_Bit_Position |
6300 Attribute_Callable |
6303 Attribute_Code_Address |
6305 Attribute_Default_Bit_Order |
6306 Attribute_Elaborated |
6307 Attribute_Elab_Body |
6308 Attribute_Elab_Spec |
6309 Attribute_External_Tag |
6310 Attribute_First_Bit |
6312 Attribute_Last_Bit |
6313 Attribute_Maximum_Alignment |
6315 Attribute_Partition_ID |
6316 Attribute_Pool_Address |
6317 Attribute_Position |
6319 Attribute_Storage_Pool |
6320 Attribute_Storage_Size |
6321 Attribute_Storage_Unit |
6323 Attribute_Target_Name |
6324 Attribute_Terminated |
6325 Attribute_To_Address |
6326 Attribute_UET_Address |
6327 Attribute_Unchecked_Access |
6328 Attribute_Universal_Literal_String |
6329 Attribute_Unrestricted_Access |
6332 Attribute_Wchar_T_Size |
6333 Attribute_Wide_Value |
6334 Attribute_Word_Size |
6337 raise Program_Error;
6341 -- At the end of the case, one more check. If we did a static evaluation
6342 -- so that the result is now a literal, then set Is_Static_Expression
6343 -- in the constant only if the prefix type is a static subtype. For
6344 -- non-static subtypes, the folding is still OK, but not static.
6346 -- An exception is the GNAT attribute Constrained_Array which is
6347 -- defined to be a static attribute in all cases.
6349 if Nkind (N) = N_Integer_Literal
6350 or else Nkind (N) = N_Real_Literal
6351 or else Nkind (N) = N_Character_Literal
6352 or else Nkind (N) = N_String_Literal
6353 or else (Is_Entity_Name (N)
6354 and then Ekind (Entity (N)) = E_Enumeration_Literal)
6356 Set_Is_Static_Expression (N, Static);
6358 -- If this is still an attribute reference, then it has not been folded
6359 -- and that means that its expressions are in a non-static context.
6361 elsif Nkind (N) = N_Attribute_Reference then
6364 -- Note: the else case not covered here are odd cases where the
6365 -- processing has transformed the attribute into something other
6366 -- than a constant. Nothing more to do in such cases.
6374 ------------------------------
6375 -- Is_Anonymous_Tagged_Base --
6376 ------------------------------
6378 function Is_Anonymous_Tagged_Base
6385 Anon = Current_Scope
6386 and then Is_Itype (Anon)
6387 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
6388 end Is_Anonymous_Tagged_Base;
6390 -----------------------
6391 -- Resolve_Attribute --
6392 -----------------------
6394 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
6395 Loc : constant Source_Ptr := Sloc (N);
6396 P : constant Node_Id := Prefix (N);
6397 Aname : constant Name_Id := Attribute_Name (N);
6398 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
6399 Btyp : constant Entity_Id := Base_Type (Typ);
6400 Index : Interp_Index;
6402 Nom_Subt : Entity_Id;
6405 -- If error during analysis, no point in continuing, except for
6406 -- array types, where we get better recovery by using unconstrained
6407 -- indices than nothing at all (see Check_Array_Type).
6410 and then Attr_Id /= Attribute_First
6411 and then Attr_Id /= Attribute_Last
6412 and then Attr_Id /= Attribute_Length
6413 and then Attr_Id /= Attribute_Range
6418 -- If attribute was universal type, reset to actual type
6420 if Etype (N) = Universal_Integer
6421 or else Etype (N) = Universal_Real
6426 -- Remaining processing depends on attribute
6434 -- For access attributes, if the prefix denotes an entity, it is
6435 -- interpreted as a name, never as a call. It may be overloaded,
6436 -- in which case resolution uses the profile of the context type.
6437 -- Otherwise prefix must be resolved.
6439 when Attribute_Access
6440 | Attribute_Unchecked_Access
6441 | Attribute_Unrestricted_Access =>
6443 if Is_Variable (P) then
6444 Note_Possible_Modification (P);
6447 if Is_Entity_Name (P) then
6448 if Is_Overloaded (P) then
6449 Get_First_Interp (P, Index, It);
6451 while Present (It.Nam) loop
6453 if Type_Conformant (Designated_Type (Typ), It.Nam) then
6454 Set_Entity (P, It.Nam);
6456 -- The prefix is definitely NOT overloaded anymore
6457 -- at this point, so we reset the Is_Overloaded
6458 -- flag to avoid any confusion when reanalyzing
6461 Set_Is_Overloaded (P, False);
6462 Generate_Reference (Entity (P), P);
6466 Get_Next_Interp (Index, It);
6469 -- If it is a subprogram name or a type, there is nothing
6472 elsif not Is_Overloadable (Entity (P))
6473 and then not Is_Type (Entity (P))
6478 Error_Msg_Name_1 := Aname;
6480 if not Is_Entity_Name (P) then
6483 elsif Is_Abstract (Entity (P))
6484 and then Is_Overloadable (Entity (P))
6486 Error_Msg_N ("prefix of % attribute cannot be abstract", P);
6487 Set_Etype (N, Any_Type);
6489 elsif Convention (Entity (P)) = Convention_Intrinsic then
6490 if Ekind (Entity (P)) = E_Enumeration_Literal then
6492 ("prefix of % attribute cannot be enumeration literal",
6496 ("prefix of % attribute cannot be intrinsic", P);
6499 Set_Etype (N, Any_Type);
6501 elsif Is_Thread_Body (Entity (P)) then
6503 ("prefix of % attribute cannot be a thread body", P);
6506 -- Assignments, return statements, components of aggregates,
6507 -- generic instantiations will require convention checks if
6508 -- the type is an access to subprogram. Given that there will
6509 -- also be accessibility checks on those, this is where the
6510 -- checks can eventually be centralized ???
6512 if Ekind (Btyp) = E_Access_Subprogram_Type
6514 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
6516 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type
6518 if Convention (Btyp) /= Convention (Entity (P)) then
6520 ("subprogram has invalid convention for context", P);
6523 Check_Subtype_Conformant
6524 (New_Id => Entity (P),
6525 Old_Id => Designated_Type (Btyp),
6529 if Attr_Id = Attribute_Unchecked_Access then
6530 Error_Msg_Name_1 := Aname;
6532 ("attribute% cannot be applied to a subprogram", P);
6534 elsif Aname = Name_Unrestricted_Access then
6535 null; -- Nothing to check
6537 -- Check the static accessibility rule of 3.10.2(32)
6538 -- In an instance body, if subprogram and type are both
6539 -- local, other rules prevent dangling references, and no
6540 -- warning is needed.
6542 elsif Attr_Id = Attribute_Access
6543 and then Subprogram_Access_Level (Entity (P)) >
6544 Type_Access_Level (Btyp)
6545 and then Ekind (Btyp) /=
6546 E_Anonymous_Access_Subprogram_Type
6547 and then Ekind (Btyp) /=
6548 E_Anonymous_Access_Protected_Subprogram_Type
6550 if not In_Instance_Body then
6552 ("subprogram must not be deeper than access type",
6555 elsif Scope (Entity (P)) /= Scope (Btyp) then
6557 ("subprogram must not be deeper than access type?",
6560 ("Constraint_Error will be raised ?", P);
6561 Set_Raises_Constraint_Error (N);
6564 -- Check the restriction of 3.10.2(32) that disallows
6565 -- the type of the access attribute to be declared
6566 -- outside a generic body when the subprogram is declared
6567 -- within that generic body.
6569 elsif Enclosing_Generic_Body (Entity (P))
6570 /= Enclosing_Generic_Body (Btyp)
6573 ("access type must not be outside generic body", P);
6577 -- if this is a renaming, an inherited operation, or a
6578 -- subprogram instance, use the original entity.
6580 if Is_Entity_Name (P)
6581 and then Is_Overloadable (Entity (P))
6582 and then Present (Alias (Entity (P)))
6585 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
6588 elsif Nkind (P) = N_Selected_Component
6589 and then Is_Overloadable (Entity (Selector_Name (P)))
6591 -- Protected operation. If operation is overloaded, must
6592 -- disambiguate. Prefix that denotes protected object itself
6593 -- is resolved with its own type.
6595 if Attr_Id = Attribute_Unchecked_Access then
6596 Error_Msg_Name_1 := Aname;
6598 ("attribute% cannot be applied to protected operation", P);
6601 Resolve (Prefix (P));
6602 Generate_Reference (Entity (Selector_Name (P)), P);
6604 elsif Is_Overloaded (P) then
6606 -- Use the designated type of the context to disambiguate.
6608 Index : Interp_Index;
6611 Get_First_Interp (P, Index, It);
6613 while Present (It.Typ) loop
6614 if Covers (Designated_Type (Typ), It.Typ) then
6615 Resolve (P, It.Typ);
6619 Get_Next_Interp (Index, It);
6626 -- X'Access is illegal if X denotes a constant and the access
6627 -- type is access-to-variable. Same for 'Unchecked_Access.
6628 -- The rule does not apply to 'Unrestricted_Access.
6630 if not (Ekind (Btyp) = E_Access_Subprogram_Type
6631 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
6632 or else (Is_Record_Type (Btyp) and then
6633 Present (Corresponding_Remote_Type (Btyp)))
6634 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
6635 or else Ekind (Btyp)
6636 = E_Anonymous_Access_Protected_Subprogram_Type
6637 or else Is_Access_Constant (Btyp)
6638 or else Is_Variable (P)
6639 or else Attr_Id = Attribute_Unrestricted_Access)
6641 if Comes_From_Source (N) then
6642 Error_Msg_N ("access-to-variable designates constant", P);
6646 if (Attr_Id = Attribute_Access
6648 Attr_Id = Attribute_Unchecked_Access)
6649 and then (Ekind (Btyp) = E_General_Access_Type
6650 or else Ekind (Btyp) = E_Anonymous_Access_Type)
6652 -- Ada 2005 (AI-230): Check the accessibility of anonymous
6653 -- access types in record and array components. For a
6654 -- component definition the level is the same of the
6655 -- enclosing composite type.
6657 if Ada_Version >= Ada_05
6658 and then Ekind (Btyp) = E_Anonymous_Access_Type
6659 and then (Is_Array_Type (Scope (Btyp))
6660 or else Ekind (Scope (Btyp)) = E_Record_Type)
6661 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
6663 -- In an instance, this is a runtime check, but one we
6664 -- know will fail, so generate an appropriate warning.
6666 if In_Instance_Body then
6668 ("?non-local pointer cannot point to local object", P);
6670 ("?Program_Error will be raised at run time", P);
6672 Make_Raise_Program_Error (Loc,
6673 Reason => PE_Accessibility_Check_Failed));
6677 ("non-local pointer cannot point to local object", P);
6681 if Is_Dependent_Component_Of_Mutable_Object (P) then
6683 ("illegal attribute for discriminant-dependent component",
6687 -- Check the static matching rule of 3.10.2(27). The
6688 -- nominal subtype of the prefix must statically
6689 -- match the designated type.
6691 Nom_Subt := Etype (P);
6693 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
6694 Nom_Subt := Etype (Nom_Subt);
6697 if Is_Tagged_Type (Designated_Type (Typ)) then
6699 -- If the attribute is in the context of an access
6700 -- parameter, then the prefix is allowed to be of
6701 -- the class-wide type (by AI-127).
6703 if Ekind (Typ) = E_Anonymous_Access_Type then
6704 if not Covers (Designated_Type (Typ), Nom_Subt)
6705 and then not Covers (Nom_Subt, Designated_Type (Typ))
6711 Desig := Designated_Type (Typ);
6713 if Is_Class_Wide_Type (Desig) then
6714 Desig := Etype (Desig);
6717 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
6722 ("type of prefix: & not compatible",
6725 ("\with &, the expected designated type",
6726 P, Designated_Type (Typ));
6731 elsif not Covers (Designated_Type (Typ), Nom_Subt)
6733 (not Is_Class_Wide_Type (Designated_Type (Typ))
6734 and then Is_Class_Wide_Type (Nom_Subt))
6737 ("type of prefix: & is not covered", P, Nom_Subt);
6739 ("\by &, the expected designated type" &
6740 " ('R'M 3.10.2 (27))", P, Designated_Type (Typ));
6743 if Is_Class_Wide_Type (Designated_Type (Typ))
6744 and then Has_Discriminants (Etype (Designated_Type (Typ)))
6745 and then Is_Constrained (Etype (Designated_Type (Typ)))
6746 and then Designated_Type (Typ) /= Nom_Subt
6748 Apply_Discriminant_Check
6749 (N, Etype (Designated_Type (Typ)));
6752 elsif not Subtypes_Statically_Match
6753 (Designated_Type (Base_Type (Typ)), Nom_Subt)
6755 not (Has_Discriminants (Designated_Type (Typ))
6758 (Designated_Type (Base_Type (Typ))))
6761 ("object subtype must statically match "
6762 & "designated subtype", P);
6764 if Is_Entity_Name (P)
6765 and then Is_Array_Type (Designated_Type (Typ))
6769 D : constant Node_Id := Declaration_Node (Entity (P));
6772 Error_Msg_N ("aliased object has explicit bounds?",
6774 Error_Msg_N ("\declare without bounds"
6775 & " (and with explicit initialization)?", D);
6776 Error_Msg_N ("\for use with unconstrained access?", D);
6781 -- Check the static accessibility rule of 3.10.2(28).
6782 -- Note that this check is not performed for the
6783 -- case of an anonymous access type, since the access
6784 -- attribute is always legal in such a context.
6786 if Attr_Id /= Attribute_Unchecked_Access
6787 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
6788 and then Ekind (Btyp) = E_General_Access_Type
6790 -- In an instance, this is a runtime check, but one we
6791 -- know will fail, so generate an appropriate warning.
6793 if In_Instance_Body then
6795 ("?non-local pointer cannot point to local object", P);
6797 ("?Program_Error will be raised at run time", P);
6799 Make_Raise_Program_Error (Loc,
6800 Reason => PE_Accessibility_Check_Failed));
6806 ("non-local pointer cannot point to local object", P);
6808 if Is_Record_Type (Current_Scope)
6809 and then (Nkind (Parent (N)) =
6810 N_Discriminant_Association
6812 Nkind (Parent (N)) =
6813 N_Index_Or_Discriminant_Constraint)
6816 Indic : Node_Id := Parent (Parent (N));
6819 while Present (Indic)
6820 and then Nkind (Indic) /= N_Subtype_Indication
6822 Indic := Parent (Indic);
6825 if Present (Indic) then
6827 ("\use an access definition for" &
6828 " the access discriminant of&", N,
6829 Entity (Subtype_Mark (Indic)));
6837 if (Ekind (Btyp) = E_Access_Protected_Subprogram_Type
6839 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type)
6840 and then Is_Entity_Name (P)
6841 and then not Is_Protected_Type (Scope (Entity (P)))
6843 Error_Msg_N ("context requires a protected subprogram", P);
6845 elsif (Ekind (Btyp) = E_Access_Subprogram_Type
6847 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type)
6848 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
6850 Error_Msg_N ("context requires a non-protected subprogram", P);
6853 -- The context cannot be a pool-specific type, but this is a
6854 -- legality rule, not a resolution rule, so it must be checked
6855 -- separately, after possibly disambiguation (see AI-245).
6857 if Ekind (Btyp) = E_Access_Type
6858 and then Attr_Id /= Attribute_Unrestricted_Access
6860 Wrong_Type (N, Typ);
6865 -- Check for incorrect atomic/volatile reference (RM C.6(12))
6867 if Attr_Id /= Attribute_Unrestricted_Access then
6868 if Is_Atomic_Object (P)
6869 and then not Is_Atomic (Designated_Type (Typ))
6872 ("access to atomic object cannot yield access-to-" &
6873 "non-atomic type", P);
6875 elsif Is_Volatile_Object (P)
6876 and then not Is_Volatile (Designated_Type (Typ))
6879 ("access to volatile object cannot yield access-to-" &
6880 "non-volatile type", P);
6888 -- Deal with resolving the type for Address attribute, overloading
6889 -- is not permitted here, since there is no context to resolve it.
6891 when Attribute_Address | Attribute_Code_Address =>
6893 -- To be safe, assume that if the address of a variable is taken,
6894 -- it may be modified via this address, so note modification.
6896 if Is_Variable (P) then
6897 Note_Possible_Modification (P);
6900 if Nkind (P) in N_Subexpr
6901 and then Is_Overloaded (P)
6903 Get_First_Interp (P, Index, It);
6904 Get_Next_Interp (Index, It);
6906 if Present (It.Nam) then
6907 Error_Msg_Name_1 := Aname;
6909 ("prefix of % attribute cannot be overloaded", N);
6914 if not Is_Entity_Name (P)
6915 or else not Is_Overloadable (Entity (P))
6917 if not Is_Task_Type (Etype (P))
6918 or else Nkind (P) = N_Explicit_Dereference
6924 -- If this is the name of a derived subprogram, or that of a
6925 -- generic actual, the address is that of the original entity.
6927 if Is_Entity_Name (P)
6928 and then Is_Overloadable (Entity (P))
6929 and then Present (Alias (Entity (P)))
6932 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
6939 -- Prefix of the AST_Entry attribute is an entry name which must
6940 -- not be resolved, since this is definitely not an entry call.
6942 when Attribute_AST_Entry =>
6949 -- Prefix of Body_Version attribute can be a subprogram name which
6950 -- must not be resolved, since this is not a call.
6952 when Attribute_Body_Version =>
6959 -- Prefix of Caller attribute is an entry name which must not
6960 -- be resolved, since this is definitely not an entry call.
6962 when Attribute_Caller =>
6969 -- Shares processing with Address attribute
6975 -- If the prefix of the Count attribute is an entry name it must not
6976 -- be resolved, since this is definitely not an entry call. However,
6977 -- if it is an element of an entry family, the index itself may
6978 -- have to be resolved because it can be a general expression.
6980 when Attribute_Count =>
6981 if Nkind (P) = N_Indexed_Component
6982 and then Is_Entity_Name (Prefix (P))
6985 Indx : constant Node_Id := First (Expressions (P));
6986 Fam : constant Entity_Id := Entity (Prefix (P));
6988 Resolve (Indx, Entry_Index_Type (Fam));
6989 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
6997 -- Prefix of the Elaborated attribute is a subprogram name which
6998 -- must not be resolved, since this is definitely not a call. Note
6999 -- that it is a library unit, so it cannot be overloaded here.
7001 when Attribute_Elaborated =>
7004 --------------------
7005 -- Mechanism_Code --
7006 --------------------
7008 -- Prefix of the Mechanism_Code attribute is a function name
7009 -- which must not be resolved. Should we check for overloaded ???
7011 when Attribute_Mechanism_Code =>
7018 -- Most processing is done in sem_dist, after determining the
7019 -- context type. Node is rewritten as a conversion to a runtime call.
7021 when Attribute_Partition_ID =>
7022 Process_Partition_Id (N);
7025 when Attribute_Pool_Address =>
7032 -- We replace the Range attribute node with a range expression
7033 -- whose bounds are the 'First and 'Last attributes applied to the
7034 -- same prefix. The reason that we do this transformation here
7035 -- instead of in the expander is that it simplifies other parts of
7036 -- the semantic analysis which assume that the Range has been
7037 -- replaced; thus it must be done even when in semantic-only mode
7038 -- (note that the RM specifically mentions this equivalence, we
7039 -- take care that the prefix is only evaluated once).
7041 when Attribute_Range => Range_Attribute :
7046 function Check_Discriminated_Prival
7049 -- The range of a private component constrained by a
7050 -- discriminant is rewritten to make the discriminant
7051 -- explicit. This solves some complex visibility problems
7052 -- related to the use of privals.
7054 --------------------------------
7055 -- Check_Discriminated_Prival --
7056 --------------------------------
7058 function Check_Discriminated_Prival
7063 if Is_Entity_Name (N)
7064 and then Ekind (Entity (N)) = E_In_Parameter
7065 and then not Within_Init_Proc
7067 return Make_Identifier (Sloc (N), Chars (Entity (N)));
7069 return Duplicate_Subexpr (N);
7071 end Check_Discriminated_Prival;
7073 -- Start of processing for Range_Attribute
7076 if not Is_Entity_Name (P)
7077 or else not Is_Type (Entity (P))
7082 -- Check whether prefix is (renaming of) private component
7083 -- of protected type.
7085 if Is_Entity_Name (P)
7086 and then Comes_From_Source (N)
7087 and then Is_Array_Type (Etype (P))
7088 and then Number_Dimensions (Etype (P)) = 1
7089 and then (Ekind (Scope (Entity (P))) = E_Protected_Type
7091 Ekind (Scope (Scope (Entity (P)))) =
7095 Check_Discriminated_Prival
7096 (Type_Low_Bound (Etype (First_Index (Etype (P)))));
7099 Check_Discriminated_Prival
7100 (Type_High_Bound (Etype (First_Index (Etype (P)))));
7104 Make_Attribute_Reference (Loc,
7105 Prefix => Duplicate_Subexpr (P),
7106 Attribute_Name => Name_Last,
7107 Expressions => Expressions (N));
7110 Make_Attribute_Reference (Loc,
7112 Attribute_Name => Name_First,
7113 Expressions => Expressions (N));
7116 -- If the original was marked as Must_Not_Freeze (see code
7117 -- in Sem_Ch3.Make_Index), then make sure the rewriting
7118 -- does not freeze either.
7120 if Must_Not_Freeze (N) then
7121 Set_Must_Not_Freeze (HB);
7122 Set_Must_Not_Freeze (LB);
7123 Set_Must_Not_Freeze (Prefix (HB));
7124 Set_Must_Not_Freeze (Prefix (LB));
7127 if Raises_Constraint_Error (Prefix (N)) then
7129 -- Preserve Sloc of prefix in the new bounds, so that
7130 -- the posted warning can be removed if we are within
7131 -- unreachable code.
7133 Set_Sloc (LB, Sloc (Prefix (N)));
7134 Set_Sloc (HB, Sloc (Prefix (N)));
7137 Rewrite (N, Make_Range (Loc, LB, HB));
7138 Analyze_And_Resolve (N, Typ);
7140 -- Normally after resolving attribute nodes, Eval_Attribute
7141 -- is called to do any possible static evaluation of the node.
7142 -- However, here since the Range attribute has just been
7143 -- transformed into a range expression it is no longer an
7144 -- attribute node and therefore the call needs to be avoided
7145 -- and is accomplished by simply returning from the procedure.
7148 end Range_Attribute;
7154 -- Prefix must not be resolved in this case, since it is not a
7155 -- real entity reference. No action of any kind is require!
7157 when Attribute_UET_Address =>
7160 ----------------------
7161 -- Unchecked_Access --
7162 ----------------------
7164 -- Processing is shared with Access
7166 -------------------------
7167 -- Unrestricted_Access --
7168 -------------------------
7170 -- Processing is shared with Access
7176 -- Apply range check. Note that we did not do this during the
7177 -- analysis phase, since we wanted Eval_Attribute to have a
7178 -- chance at finding an illegal out of range value.
7180 when Attribute_Val =>
7182 -- Note that we do our own Eval_Attribute call here rather than
7183 -- use the common one, because we need to do processing after
7184 -- the call, as per above comment.
7188 -- Eval_Attribute may replace the node with a raise CE, or
7189 -- fold it to a constant. Obviously we only apply a scalar
7190 -- range check if this did not happen!
7192 if Nkind (N) = N_Attribute_Reference
7193 and then Attribute_Name (N) = Name_Val
7195 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
7204 -- Prefix of Version attribute can be a subprogram name which
7205 -- must not be resolved, since this is not a call.
7207 when Attribute_Version =>
7210 ----------------------
7211 -- Other Attributes --
7212 ----------------------
7214 -- For other attributes, resolve prefix unless it is a type. If
7215 -- the attribute reference itself is a type name ('Base and 'Class)
7216 -- then this is only legal within a task or protected record.
7219 if not Is_Entity_Name (P)
7220 or else not Is_Type (Entity (P))
7225 -- If the attribute reference itself is a type name ('Base,
7226 -- 'Class) then this is only legal within a task or protected
7227 -- record. What is this all about ???
7229 if Is_Entity_Name (N)
7230 and then Is_Type (Entity (N))
7232 if Is_Concurrent_Type (Entity (N))
7233 and then In_Open_Scopes (Entity (P))
7238 ("invalid use of subtype name in expression or call", N);
7242 -- For attributes whose argument may be a string, complete
7243 -- resolution of argument now. This avoids premature expansion
7244 -- (and the creation of transient scopes) before the attribute
7245 -- reference is resolved.
7248 when Attribute_Value =>
7249 Resolve (First (Expressions (N)), Standard_String);
7251 when Attribute_Wide_Value =>
7252 Resolve (First (Expressions (N)), Standard_Wide_String);
7254 when others => null;
7258 -- Normally the Freezing is done by Resolve but sometimes the Prefix
7259 -- is not resolved, in which case the freezing must be done now.
7261 Freeze_Expression (P);
7263 -- Finally perform static evaluation on the attribute reference
7267 end Resolve_Attribute;