1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2008, 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 3, 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 COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
28 with Atree; use Atree;
29 with Casing; use Casing;
30 with Checks; use Checks;
31 with Einfo; use Einfo;
32 with Errout; use Errout;
34 with Exp_Dist; use Exp_Dist;
35 with Exp_Util; use Exp_Util;
36 with Expander; use Expander;
37 with Freeze; use Freeze;
38 with Itypes; use Itypes;
40 with Lib.Xref; use Lib.Xref;
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 Stringt; use Stringt;
62 with Stylesw; use Stylesw;
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;
70 package body Sem_Attr is
72 True_Value : constant Uint := Uint_1;
73 False_Value : constant Uint := Uint_0;
74 -- Synonyms to be used when these constants are used as Boolean values
76 Bad_Attribute : exception;
77 -- Exception raised if an error is detected during attribute processing,
78 -- used so that we can abandon the processing so we don't run into
79 -- trouble with cascaded errors.
81 -- The following array is the list of attributes defined in the Ada 83 RM
82 -- that are not included in Ada 95, but still get recognized in GNAT.
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 -- The following array is the list of attributes defined in the Ada 2005
130 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
131 -- but in Ada 95 they are considered to be implementation defined.
133 Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'(
134 Attribute_Machine_Rounding |
136 Attribute_Stream_Size |
137 Attribute_Wide_Wide_Width => True,
140 -- The following array contains all attributes that imply a modification
141 -- of their prefixes or result in an access value. Such prefixes can be
142 -- considered as lvalues.
144 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
145 Attribute_Class_Array'(
150 Attribute_Unchecked_Access |
151 Attribute_Unrestricted_Access => True,
154 -----------------------
155 -- Local_Subprograms --
156 -----------------------
158 procedure Eval_Attribute (N : Node_Id);
159 -- Performs compile time evaluation of attributes where possible, leaving
160 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
161 -- set, and replacing the node with a literal node if the value can be
162 -- computed at compile time. All static attribute references are folded,
163 -- as well as a number of cases of non-static attributes that can always
164 -- be computed at compile time (e.g. floating-point model attributes that
165 -- are applied to non-static subtypes). Of course in such cases, the
166 -- Is_Static_Expression flag will not be set on the resulting literal.
167 -- Note that the only required action of this procedure is to catch the
168 -- static expression cases as described in the RM. Folding of other cases
169 -- is done where convenient, but some additional non-static folding is in
170 -- N_Expand_Attribute_Reference in cases where this is more convenient.
172 function Is_Anonymous_Tagged_Base
176 -- For derived tagged types that constrain parent discriminants we build
177 -- an anonymous unconstrained base type. We need to recognize the relation
178 -- between the two when analyzing an access attribute for a constrained
179 -- component, before the full declaration for Typ has been analyzed, and
180 -- where therefore the prefix of the attribute does not match the enclosing
183 -----------------------
184 -- Analyze_Attribute --
185 -----------------------
187 procedure Analyze_Attribute (N : Node_Id) is
188 Loc : constant Source_Ptr := Sloc (N);
189 Aname : constant Name_Id := Attribute_Name (N);
190 P : constant Node_Id := Prefix (N);
191 Exprs : constant List_Id := Expressions (N);
192 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
197 -- Type of prefix after analysis
199 P_Base_Type : Entity_Id;
200 -- Base type of prefix after analysis
202 -----------------------
203 -- Local Subprograms --
204 -----------------------
206 procedure Analyze_Access_Attribute;
207 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
208 -- Internally, Id distinguishes which of the three cases is involved.
210 procedure Check_Array_Or_Scalar_Type;
211 -- Common procedure used by First, Last, Range attribute to check
212 -- that the prefix is a constrained array or scalar type, or a name
213 -- of an array object, and that an argument appears only if appropriate
214 -- (i.e. only in the array case).
216 procedure Check_Array_Type;
217 -- Common semantic checks for all array attributes. Checks that the
218 -- prefix is a constrained array type or the name of an array object.
219 -- The error message for non-arrays is specialized appropriately.
221 procedure Check_Asm_Attribute;
222 -- Common semantic checks for Asm_Input and Asm_Output attributes
224 procedure Check_Component;
225 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
226 -- Position. Checks prefix is an appropriate selected component.
228 procedure Check_Decimal_Fixed_Point_Type;
229 -- Check that prefix of attribute N is a decimal fixed-point type
231 procedure Check_Dereference;
232 -- If the prefix of attribute is an object of an access type, then
233 -- introduce an explicit deference, and adjust P_Type accordingly.
235 procedure Check_Discrete_Type;
236 -- Verify that prefix of attribute N is a discrete type
239 -- Check that no attribute arguments are present
241 procedure Check_Either_E0_Or_E1;
242 -- Check that there are zero or one attribute arguments present
245 -- Check that exactly one attribute argument is present
248 -- Check that two attribute arguments are present
250 procedure Check_Enum_Image;
251 -- If the prefix type is an enumeration type, set all its literals
252 -- as referenced, since the image function could possibly end up
253 -- referencing any of the literals indirectly. Same for Enum_Val.
255 procedure Check_Fixed_Point_Type;
256 -- Verify that prefix of attribute N is a fixed type
258 procedure Check_Fixed_Point_Type_0;
259 -- Verify that prefix of attribute N is a fixed type and that
260 -- no attribute expressions are present
262 procedure Check_Floating_Point_Type;
263 -- Verify that prefix of attribute N is a float type
265 procedure Check_Floating_Point_Type_0;
266 -- Verify that prefix of attribute N is a float type and that
267 -- no attribute expressions are present
269 procedure Check_Floating_Point_Type_1;
270 -- Verify that prefix of attribute N is a float type and that
271 -- exactly one attribute expression is present
273 procedure Check_Floating_Point_Type_2;
274 -- Verify that prefix of attribute N is a float type and that
275 -- two attribute expressions are present
277 procedure Legal_Formal_Attribute;
278 -- Common processing for attributes Definite and Has_Discriminants.
279 -- Checks that prefix is generic indefinite formal type.
281 procedure Check_Integer_Type;
282 -- Verify that prefix of attribute N is an integer type
284 procedure Check_Library_Unit;
285 -- Verify that prefix of attribute N is a library unit
287 procedure Check_Modular_Integer_Type;
288 -- Verify that prefix of attribute N is a modular integer type
290 procedure Check_Not_CPP_Type;
291 -- Check that P (the prefix of the attribute) is not an CPP type
292 -- for which no Ada predefined primitive is available.
294 procedure Check_Not_Incomplete_Type;
295 -- Check that P (the prefix of the attribute) is not an incomplete
296 -- type or a private type for which no full view has been given.
298 procedure Check_Object_Reference (P : Node_Id);
299 -- Check that P (the prefix of the attribute) is an object reference
301 procedure Check_Program_Unit;
302 -- Verify that prefix of attribute N is a program unit
304 procedure Check_Real_Type;
305 -- Verify that prefix of attribute N is fixed or float type
307 procedure Check_Scalar_Type;
308 -- Verify that prefix of attribute N is a scalar type
310 procedure Check_Standard_Prefix;
311 -- Verify that prefix of attribute N is package Standard
313 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
314 -- Validity checking for stream attribute. Nam is the TSS name of the
315 -- corresponding possible defined attribute function (e.g. for the
316 -- Read attribute, Nam will be TSS_Stream_Read).
318 procedure Check_PolyORB_Attribute;
319 -- Validity checking for PolyORB/DSA attribute
321 procedure Check_Task_Prefix;
322 -- Verify that prefix of attribute N is a task or task type
324 procedure Check_Type;
325 -- Verify that the prefix of attribute N is a type
327 procedure Check_Unit_Name (Nod : Node_Id);
328 -- Check that Nod is of the form of a library unit name, i.e that
329 -- it is an identifier, or a selected component whose prefix is
330 -- itself of the form of a library unit name. Note that this is
331 -- quite different from Check_Program_Unit, since it only checks
332 -- the syntactic form of the name, not the semantic identity. This
333 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
334 -- UET_Address) which can refer to non-visible unit.
336 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
337 pragma No_Return (Error_Attr);
338 procedure Error_Attr;
339 pragma No_Return (Error_Attr);
340 -- Posts error using Error_Msg_N at given node, sets type of attribute
341 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
342 -- semantic processing. The message typically contains a % insertion
343 -- character which is replaced by the attribute name. The call with
344 -- no arguments is used when the caller has already generated the
345 -- required error messages.
347 procedure Error_Attr_P (Msg : String);
348 pragma No_Return (Error_Attr);
349 -- Like Error_Attr, but error is posted at the start of the prefix
351 procedure Standard_Attribute (Val : Int);
352 -- Used to process attributes whose prefix is package Standard which
353 -- yield values of type Universal_Integer. The attribute reference
354 -- node is rewritten with an integer literal of the given value.
356 procedure Unexpected_Argument (En : Node_Id);
357 -- Signal unexpected attribute argument (En is the argument)
359 procedure Validate_Non_Static_Attribute_Function_Call;
360 -- Called when processing an attribute that is a function call to a
361 -- non-static function, i.e. an attribute function that either takes
362 -- non-scalar arguments or returns a non-scalar result. Verifies that
363 -- such a call does not appear in a preelaborable context.
365 ------------------------------
366 -- Analyze_Access_Attribute --
367 ------------------------------
369 procedure Analyze_Access_Attribute is
370 Acc_Type : Entity_Id;
375 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
376 -- Build an access-to-object type whose designated type is DT,
377 -- and whose Ekind is appropriate to the attribute type. The
378 -- type that is constructed is returned as the result.
380 procedure Build_Access_Subprogram_Type (P : Node_Id);
381 -- Build an access to subprogram whose designated type is the type of
382 -- the prefix. If prefix is overloaded, so is the node itself. The
383 -- result is stored in Acc_Type.
385 function OK_Self_Reference return Boolean;
386 -- An access reference whose prefix is a type can legally appear
387 -- within an aggregate, where it is obtained by expansion of
388 -- a defaulted aggregate. The enclosing aggregate that contains
389 -- the self-referenced is flagged so that the self-reference can
390 -- be expanded into a reference to the target object (see exp_aggr).
392 ------------------------------
393 -- Build_Access_Object_Type --
394 ------------------------------
396 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
397 Typ : constant Entity_Id :=
399 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
401 Set_Etype (Typ, Typ);
403 Set_Associated_Node_For_Itype (Typ, N);
404 Set_Directly_Designated_Type (Typ, DT);
406 end Build_Access_Object_Type;
408 ----------------------------------
409 -- Build_Access_Subprogram_Type --
410 ----------------------------------
412 procedure Build_Access_Subprogram_Type (P : Node_Id) is
413 Index : Interp_Index;
416 procedure Check_Local_Access (E : Entity_Id);
417 -- Deal with possible access to local subprogram. If we have such
418 -- an access, we set a flag to kill all tracked values on any call
419 -- because this access value may be passed around, and any called
420 -- code might use it to access a local procedure which clobbers a
423 function Get_Kind (E : Entity_Id) return Entity_Kind;
424 -- Distinguish between access to regular/protected subprograms
426 ------------------------
427 -- Check_Local_Access --
428 ------------------------
430 procedure Check_Local_Access (E : Entity_Id) is
432 if not Is_Library_Level_Entity (E) then
433 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
435 end Check_Local_Access;
441 function Get_Kind (E : Entity_Id) return Entity_Kind is
443 if Convention (E) = Convention_Protected then
444 return E_Access_Protected_Subprogram_Type;
446 return E_Access_Subprogram_Type;
450 -- Start of processing for Build_Access_Subprogram_Type
453 -- In the case of an access to subprogram, use the name of the
454 -- subprogram itself as the designated type. Type-checking in
455 -- this case compares the signatures of the designated types.
457 -- Note: This fragment of the tree is temporarily malformed
458 -- because the correct tree requires an E_Subprogram_Type entity
459 -- as the designated type. In most cases this designated type is
460 -- later overridden by the semantics with the type imposed by the
461 -- context during the resolution phase. In the specific case of
462 -- the expression Address!(Prim'Unrestricted_Access), used to
463 -- initialize slots of dispatch tables, this work will be done by
464 -- the expander (see Exp_Aggr).
466 -- The reason to temporarily add this kind of node to the tree
467 -- instead of a proper E_Subprogram_Type itype, is the following:
468 -- in case of errors found in the source file we report better
469 -- error messages. For example, instead of generating the
472 -- "expected access to subprogram with profile
473 -- defined at line X"
475 -- we currently generate:
477 -- "expected access to function Z defined at line X"
479 Set_Etype (N, Any_Type);
481 if not Is_Overloaded (P) then
482 Check_Local_Access (Entity (P));
484 if not Is_Intrinsic_Subprogram (Entity (P)) then
485 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
486 Set_Is_Public (Acc_Type, False);
487 Set_Etype (Acc_Type, Acc_Type);
488 Set_Convention (Acc_Type, Convention (Entity (P)));
489 Set_Directly_Designated_Type (Acc_Type, Entity (P));
490 Set_Etype (N, Acc_Type);
491 Freeze_Before (N, Acc_Type);
495 Get_First_Interp (P, Index, It);
496 while Present (It.Nam) loop
497 Check_Local_Access (It.Nam);
499 if not Is_Intrinsic_Subprogram (It.Nam) then
500 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
501 Set_Is_Public (Acc_Type, False);
502 Set_Etype (Acc_Type, Acc_Type);
503 Set_Convention (Acc_Type, Convention (It.Nam));
504 Set_Directly_Designated_Type (Acc_Type, It.Nam);
505 Add_One_Interp (N, Acc_Type, Acc_Type);
506 Freeze_Before (N, Acc_Type);
509 Get_Next_Interp (Index, It);
513 -- Cannot be applied to intrinsic. Looking at the tests above,
514 -- the only way Etype (N) can still be set to Any_Type is if
515 -- Is_Intrinsic_Subprogram was True for some referenced entity.
517 if Etype (N) = Any_Type then
518 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
520 end Build_Access_Subprogram_Type;
522 ----------------------
523 -- OK_Self_Reference --
524 ----------------------
526 function OK_Self_Reference return Boolean is
533 (Nkind (Par) = N_Component_Association
534 or else Nkind (Par) in N_Subexpr)
536 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
537 if Etype (Par) = Typ then
538 Set_Has_Self_Reference (Par);
546 -- No enclosing aggregate, or not a self-reference
549 end OK_Self_Reference;
551 -- Start of processing for Analyze_Access_Attribute
556 if Nkind (P) = N_Character_Literal then
558 ("prefix of % attribute cannot be enumeration literal");
561 -- Case of access to subprogram
563 if Is_Entity_Name (P)
564 and then Is_Overloadable (Entity (P))
566 if Has_Pragma_Inline_Always (Entity (P)) then
568 ("prefix of % attribute cannot be Inline_Always subprogram");
571 if Aname = Name_Unchecked_Access then
572 Error_Attr ("attribute% cannot be applied to a subprogram", P);
575 -- Build the appropriate subprogram type
577 Build_Access_Subprogram_Type (P);
579 -- For unrestricted access, kill current values, since this
580 -- attribute allows a reference to a local subprogram that
581 -- could modify local variables to be passed out of scope
583 if Aname = Name_Unrestricted_Access then
585 -- Do not kill values on nodes initializing dispatch tables
586 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
587 -- is currently generated by the expander only for this
588 -- purpose. Done to keep the quality of warnings currently
589 -- generated by the compiler (otherwise any declaration of
590 -- a tagged type cleans constant indications from its scope).
592 if Nkind (Parent (N)) = N_Unchecked_Type_Conversion
593 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
595 Etype (Parent (N)) = RTE (RE_Size_Ptr))
596 and then Is_Dispatching_Operation
597 (Directly_Designated_Type (Etype (N)))
607 -- Component is an operation of a protected type
609 elsif Nkind (P) = N_Selected_Component
610 and then Is_Overloadable (Entity (Selector_Name (P)))
612 if Ekind (Entity (Selector_Name (P))) = E_Entry then
613 Error_Attr_P ("prefix of % attribute must be subprogram");
616 Build_Access_Subprogram_Type (Selector_Name (P));
620 -- Deal with incorrect reference to a type, but note that some
621 -- accesses are allowed: references to the current type instance,
622 -- or in Ada 2005 self-referential pointer in a default-initialized
625 if Is_Entity_Name (P) then
628 -- The reference may appear in an aggregate that has been expanded
629 -- into a loop. Locate scope of type definition, if any.
631 Scop := Current_Scope;
632 while Ekind (Scop) = E_Loop loop
633 Scop := Scope (Scop);
636 if Is_Type (Typ) then
638 -- OK if we are within the scope of a limited type
639 -- let's mark the component as having per object constraint
641 if Is_Anonymous_Tagged_Base (Scop, Typ) then
649 Q : Node_Id := Parent (N);
653 and then Nkind (Q) /= N_Component_Declaration
659 Set_Has_Per_Object_Constraint (
660 Defining_Identifier (Q), True);
664 if Nkind (P) = N_Expanded_Name then
666 ("current instance prefix must be a direct name", P);
669 -- If a current instance attribute appears in a component
670 -- constraint it must appear alone; other contexts (spec-
671 -- expressions, within a task body) are not subject to this
674 if not In_Spec_Expression
675 and then not Has_Completion (Scop)
677 Nkind_In (Parent (N), N_Discriminant_Association,
678 N_Index_Or_Discriminant_Constraint)
681 ("current instance attribute must appear alone", N);
684 -- OK if we are in initialization procedure for the type
685 -- in question, in which case the reference to the type
686 -- is rewritten as a reference to the current object.
688 elsif Ekind (Scop) = E_Procedure
689 and then Is_Init_Proc (Scop)
690 and then Etype (First_Formal (Scop)) = Typ
693 Make_Attribute_Reference (Loc,
694 Prefix => Make_Identifier (Loc, Name_uInit),
695 Attribute_Name => Name_Unrestricted_Access));
699 -- OK if a task type, this test needs sharpening up ???
701 elsif Is_Task_Type (Typ) then
704 -- OK if self-reference in an aggregate in Ada 2005, and
705 -- the reference comes from a copied default expression.
707 -- Note that we check legality of self-reference even if the
708 -- expression comes from source, e.g. when a single component
709 -- association in an aggregate has a box association.
711 elsif Ada_Version >= Ada_05
712 and then OK_Self_Reference
716 -- OK if reference to the current instance of a protected
719 elsif Is_Protected_Self_Reference (P) then
722 -- Otherwise we have an error case
725 Error_Attr ("% attribute cannot be applied to type", P);
731 -- If we fall through, we have a normal access to object case.
732 -- Unrestricted_Access is legal wherever an allocator would be
733 -- legal, so its Etype is set to E_Allocator. The expected type
734 -- of the other attributes is a general access type, and therefore
735 -- we label them with E_Access_Attribute_Type.
737 if not Is_Overloaded (P) then
738 Acc_Type := Build_Access_Object_Type (P_Type);
739 Set_Etype (N, Acc_Type);
742 Index : Interp_Index;
745 Set_Etype (N, Any_Type);
746 Get_First_Interp (P, Index, It);
747 while Present (It.Typ) loop
748 Acc_Type := Build_Access_Object_Type (It.Typ);
749 Add_One_Interp (N, Acc_Type, Acc_Type);
750 Get_Next_Interp (Index, It);
755 -- Special cases when we can find a prefix that is an entity name
764 if Is_Entity_Name (PP) then
767 -- If we have an access to an object, and the attribute
768 -- comes from source, then set the object as potentially
769 -- source modified. We do this because the resulting access
770 -- pointer can be used to modify the variable, and we might
771 -- not detect this, leading to some junk warnings.
773 Set_Never_Set_In_Source (Ent, False);
775 -- Mark entity as address taken, and kill current values
777 Set_Address_Taken (Ent);
778 Kill_Current_Values (Ent);
781 elsif Nkind_In (PP, N_Selected_Component,
792 -- Check for aliased view unless unrestricted case. We allow a
793 -- nonaliased prefix when within an instance because the prefix may
794 -- have been a tagged formal object, which is defined to be aliased
795 -- even when the actual might not be (other instance cases will have
796 -- been caught in the generic). Similarly, within an inlined body we
797 -- know that the attribute is legal in the original subprogram, and
798 -- therefore legal in the expansion.
800 if Aname /= Name_Unrestricted_Access
801 and then not Is_Aliased_View (P)
802 and then not In_Instance
803 and then not In_Inlined_Body
805 Error_Attr_P ("prefix of % attribute must be aliased");
807 end Analyze_Access_Attribute;
809 --------------------------------
810 -- Check_Array_Or_Scalar_Type --
811 --------------------------------
813 procedure Check_Array_Or_Scalar_Type is
817 -- Dimension number for array attributes
820 -- Case of string literal or string literal subtype. These cases
821 -- cannot arise from legal Ada code, but the expander is allowed
822 -- to generate them. They require special handling because string
823 -- literal subtypes do not have standard bounds (the whole idea
824 -- of these subtypes is to avoid having to generate the bounds)
826 if Ekind (P_Type) = E_String_Literal_Subtype then
827 Set_Etype (N, Etype (First_Index (P_Base_Type)));
832 elsif Is_Scalar_Type (P_Type) then
836 Error_Attr ("invalid argument in % attribute", E1);
838 Set_Etype (N, P_Base_Type);
842 -- The following is a special test to allow 'First to apply to
843 -- private scalar types if the attribute comes from generated
844 -- code. This occurs in the case of Normalize_Scalars code.
846 elsif Is_Private_Type (P_Type)
847 and then Present (Full_View (P_Type))
848 and then Is_Scalar_Type (Full_View (P_Type))
849 and then not Comes_From_Source (N)
851 Set_Etype (N, Implementation_Base_Type (P_Type));
853 -- Array types other than string literal subtypes handled above
858 -- We know prefix is an array type, or the name of an array
859 -- object, and that the expression, if present, is static
860 -- and within the range of the dimensions of the type.
862 pragma Assert (Is_Array_Type (P_Type));
863 Index := First_Index (P_Base_Type);
867 -- First dimension assumed
869 Set_Etype (N, Base_Type (Etype (Index)));
872 D := UI_To_Int (Intval (E1));
874 for J in 1 .. D - 1 loop
878 Set_Etype (N, Base_Type (Etype (Index)));
879 Set_Etype (E1, Standard_Integer);
882 end Check_Array_Or_Scalar_Type;
884 ----------------------
885 -- Check_Array_Type --
886 ----------------------
888 procedure Check_Array_Type is
890 -- Dimension number for array attributes
893 -- If the type is a string literal type, then this must be generated
894 -- internally, and no further check is required on its legality.
896 if Ekind (P_Type) = E_String_Literal_Subtype then
899 -- If the type is a composite, it is an illegal aggregate, no point
902 elsif P_Type = Any_Composite then
906 -- Normal case of array type or subtype
908 Check_Either_E0_Or_E1;
911 if Is_Array_Type (P_Type) then
912 if not Is_Constrained (P_Type)
913 and then Is_Entity_Name (P)
914 and then Is_Type (Entity (P))
916 -- Note: we do not call Error_Attr here, since we prefer to
917 -- continue, using the relevant index type of the array,
918 -- even though it is unconstrained. This gives better error
919 -- recovery behavior.
921 Error_Msg_Name_1 := Aname;
923 ("prefix for % attribute must be constrained array", P);
926 D := Number_Dimensions (P_Type);
929 if Is_Private_Type (P_Type) then
930 Error_Attr_P ("prefix for % attribute may not be private type");
932 elsif Is_Access_Type (P_Type)
933 and then Is_Array_Type (Designated_Type (P_Type))
934 and then Is_Entity_Name (P)
935 and then Is_Type (Entity (P))
937 Error_Attr_P ("prefix of % attribute cannot be access type");
939 elsif Attr_Id = Attribute_First
941 Attr_Id = Attribute_Last
943 Error_Attr ("invalid prefix for % attribute", P);
946 Error_Attr_P ("prefix for % attribute must be array");
951 Resolve (E1, Any_Integer);
952 Set_Etype (E1, Standard_Integer);
954 if not Is_Static_Expression (E1)
955 or else Raises_Constraint_Error (E1)
958 ("expression for dimension must be static!", E1);
961 elsif UI_To_Int (Expr_Value (E1)) > D
962 or else UI_To_Int (Expr_Value (E1)) < 1
964 Error_Attr ("invalid dimension number for array type", E1);
968 if (Style_Check and Style_Check_Array_Attribute_Index)
969 and then Comes_From_Source (N)
971 Style.Check_Array_Attribute_Index (N, E1, D);
973 end Check_Array_Type;
975 -------------------------
976 -- Check_Asm_Attribute --
977 -------------------------
979 procedure Check_Asm_Attribute is
984 -- Check first argument is static string expression
986 Analyze_And_Resolve (E1, Standard_String);
988 if Etype (E1) = Any_Type then
991 elsif not Is_OK_Static_Expression (E1) then
993 ("constraint argument must be static string expression!", E1);
997 -- Check second argument is right type
999 Analyze_And_Resolve (E2, Entity (P));
1001 -- Note: that is all we need to do, we don't need to check
1002 -- that it appears in a correct context. The Ada type system
1003 -- will do that for us.
1005 end Check_Asm_Attribute;
1007 ---------------------
1008 -- Check_Component --
1009 ---------------------
1011 procedure Check_Component is
1015 if Nkind (P) /= N_Selected_Component
1017 (Ekind (Entity (Selector_Name (P))) /= E_Component
1019 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1021 Error_Attr_P ("prefix for % attribute must be selected component");
1023 end Check_Component;
1025 ------------------------------------
1026 -- Check_Decimal_Fixed_Point_Type --
1027 ------------------------------------
1029 procedure Check_Decimal_Fixed_Point_Type is
1033 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1034 Error_Attr_P ("prefix of % attribute must be decimal type");
1036 end Check_Decimal_Fixed_Point_Type;
1038 -----------------------
1039 -- Check_Dereference --
1040 -----------------------
1042 procedure Check_Dereference is
1045 -- Case of a subtype mark
1047 if Is_Entity_Name (P)
1048 and then Is_Type (Entity (P))
1053 -- Case of an expression
1057 if Is_Access_Type (P_Type) then
1059 -- If there is an implicit dereference, then we must freeze
1060 -- the designated type of the access type, since the type of
1061 -- the referenced array is this type (see AI95-00106).
1063 Freeze_Before (N, Designated_Type (P_Type));
1066 Make_Explicit_Dereference (Sloc (P),
1067 Prefix => Relocate_Node (P)));
1069 Analyze_And_Resolve (P);
1070 P_Type := Etype (P);
1072 if P_Type = Any_Type then
1073 raise Bad_Attribute;
1076 P_Base_Type := Base_Type (P_Type);
1078 end Check_Dereference;
1080 -------------------------
1081 -- Check_Discrete_Type --
1082 -------------------------
1084 procedure Check_Discrete_Type is
1088 if not Is_Discrete_Type (P_Type) then
1089 Error_Attr_P ("prefix of % attribute must be discrete type");
1091 end Check_Discrete_Type;
1097 procedure Check_E0 is
1099 if Present (E1) then
1100 Unexpected_Argument (E1);
1108 procedure Check_E1 is
1110 Check_Either_E0_Or_E1;
1114 -- Special-case attributes that are functions and that appear as
1115 -- the prefix of another attribute. Error is posted on parent.
1117 if Nkind (Parent (N)) = N_Attribute_Reference
1118 and then (Attribute_Name (Parent (N)) = Name_Address
1120 Attribute_Name (Parent (N)) = Name_Code_Address
1122 Attribute_Name (Parent (N)) = Name_Access)
1124 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1125 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1126 Set_Etype (Parent (N), Any_Type);
1127 Set_Entity (Parent (N), Any_Type);
1128 raise Bad_Attribute;
1131 Error_Attr ("missing argument for % attribute", N);
1140 procedure Check_E2 is
1143 Error_Attr ("missing arguments for % attribute (2 required)", N);
1145 Error_Attr ("missing argument for % attribute (2 required)", N);
1149 ---------------------------
1150 -- Check_Either_E0_Or_E1 --
1151 ---------------------------
1153 procedure Check_Either_E0_Or_E1 is
1155 if Present (E2) then
1156 Unexpected_Argument (E2);
1158 end Check_Either_E0_Or_E1;
1160 ----------------------
1161 -- Check_Enum_Image --
1162 ----------------------
1164 procedure Check_Enum_Image is
1167 if Is_Enumeration_Type (P_Base_Type) then
1168 Lit := First_Literal (P_Base_Type);
1169 while Present (Lit) loop
1170 Set_Referenced (Lit);
1174 end Check_Enum_Image;
1176 ----------------------------
1177 -- Check_Fixed_Point_Type --
1178 ----------------------------
1180 procedure Check_Fixed_Point_Type is
1184 if not Is_Fixed_Point_Type (P_Type) then
1185 Error_Attr_P ("prefix of % attribute must be fixed point type");
1187 end Check_Fixed_Point_Type;
1189 ------------------------------
1190 -- Check_Fixed_Point_Type_0 --
1191 ------------------------------
1193 procedure Check_Fixed_Point_Type_0 is
1195 Check_Fixed_Point_Type;
1197 end Check_Fixed_Point_Type_0;
1199 -------------------------------
1200 -- Check_Floating_Point_Type --
1201 -------------------------------
1203 procedure Check_Floating_Point_Type is
1207 if not Is_Floating_Point_Type (P_Type) then
1208 Error_Attr_P ("prefix of % attribute must be float type");
1210 end Check_Floating_Point_Type;
1212 ---------------------------------
1213 -- Check_Floating_Point_Type_0 --
1214 ---------------------------------
1216 procedure Check_Floating_Point_Type_0 is
1218 Check_Floating_Point_Type;
1220 end Check_Floating_Point_Type_0;
1222 ---------------------------------
1223 -- Check_Floating_Point_Type_1 --
1224 ---------------------------------
1226 procedure Check_Floating_Point_Type_1 is
1228 Check_Floating_Point_Type;
1230 end Check_Floating_Point_Type_1;
1232 ---------------------------------
1233 -- Check_Floating_Point_Type_2 --
1234 ---------------------------------
1236 procedure Check_Floating_Point_Type_2 is
1238 Check_Floating_Point_Type;
1240 end Check_Floating_Point_Type_2;
1242 ------------------------
1243 -- Check_Integer_Type --
1244 ------------------------
1246 procedure Check_Integer_Type is
1250 if not Is_Integer_Type (P_Type) then
1251 Error_Attr_P ("prefix of % attribute must be integer type");
1253 end Check_Integer_Type;
1255 ------------------------
1256 -- Check_Library_Unit --
1257 ------------------------
1259 procedure Check_Library_Unit is
1261 if not Is_Compilation_Unit (Entity (P)) then
1262 Error_Attr_P ("prefix of % attribute must be library unit");
1264 end Check_Library_Unit;
1266 --------------------------------
1267 -- Check_Modular_Integer_Type --
1268 --------------------------------
1270 procedure Check_Modular_Integer_Type is
1274 if not Is_Modular_Integer_Type (P_Type) then
1276 ("prefix of % attribute must be modular integer type");
1278 end Check_Modular_Integer_Type;
1280 ------------------------
1281 -- Check_Not_CPP_Type --
1282 ------------------------
1284 procedure Check_Not_CPP_Type is
1286 if Is_Tagged_Type (Etype (P))
1287 and then Convention (Etype (P)) = Convention_CPP
1288 and then Is_CPP_Class (Root_Type (Etype (P)))
1291 ("invalid use of % attribute with 'C'P'P tagged type");
1293 end Check_Not_CPP_Type;
1295 -------------------------------
1296 -- Check_Not_Incomplete_Type --
1297 -------------------------------
1299 procedure Check_Not_Incomplete_Type is
1304 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1305 -- dereference we have to check wrong uses of incomplete types
1306 -- (other wrong uses are checked at their freezing point).
1308 -- Example 1: Limited-with
1310 -- limited with Pkg;
1312 -- type Acc is access Pkg.T;
1314 -- S : Integer := X.all'Size; -- ERROR
1317 -- Example 2: Tagged incomplete
1319 -- type T is tagged;
1320 -- type Acc is access all T;
1322 -- S : constant Integer := X.all'Size; -- ERROR
1323 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1325 if Ada_Version >= Ada_05
1326 and then Nkind (P) = N_Explicit_Dereference
1329 while Nkind (E) = N_Explicit_Dereference loop
1333 if From_With_Type (Etype (E)) then
1335 ("prefix of % attribute cannot be an incomplete type");
1338 if Is_Access_Type (Etype (E)) then
1339 Typ := Directly_Designated_Type (Etype (E));
1344 if Ekind (Typ) = E_Incomplete_Type
1345 and then No (Full_View (Typ))
1348 ("prefix of % attribute cannot be an incomplete type");
1353 if not Is_Entity_Name (P)
1354 or else not Is_Type (Entity (P))
1355 or else In_Spec_Expression
1359 Check_Fully_Declared (P_Type, P);
1361 end Check_Not_Incomplete_Type;
1363 ----------------------------
1364 -- Check_Object_Reference --
1365 ----------------------------
1367 procedure Check_Object_Reference (P : Node_Id) is
1371 -- If we need an object, and we have a prefix that is the name of
1372 -- a function entity, convert it into a function call.
1374 if Is_Entity_Name (P)
1375 and then Ekind (Entity (P)) = E_Function
1377 Rtyp := Etype (Entity (P));
1380 Make_Function_Call (Sloc (P),
1381 Name => Relocate_Node (P)));
1383 Analyze_And_Resolve (P, Rtyp);
1385 -- Otherwise we must have an object reference
1387 elsif not Is_Object_Reference (P) then
1388 Error_Attr_P ("prefix of % attribute must be object");
1390 end Check_Object_Reference;
1392 ----------------------------
1393 -- Check_PolyORB_Attribute --
1394 ----------------------------
1396 procedure Check_PolyORB_Attribute is
1398 Validate_Non_Static_Attribute_Function_Call;
1403 if Get_PCS_Name /= Name_PolyORB_DSA then
1405 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
1407 end Check_PolyORB_Attribute;
1409 ------------------------
1410 -- Check_Program_Unit --
1411 ------------------------
1413 procedure Check_Program_Unit is
1415 if Is_Entity_Name (P) then
1417 K : constant Entity_Kind := Ekind (Entity (P));
1418 T : constant Entity_Id := Etype (Entity (P));
1421 if K in Subprogram_Kind
1422 or else K in Task_Kind
1423 or else K in Protected_Kind
1424 or else K = E_Package
1425 or else K in Generic_Unit_Kind
1426 or else (K = E_Variable
1430 Is_Protected_Type (T)))
1437 Error_Attr_P ("prefix of % attribute must be program unit");
1438 end Check_Program_Unit;
1440 ---------------------
1441 -- Check_Real_Type --
1442 ---------------------
1444 procedure Check_Real_Type is
1448 if not Is_Real_Type (P_Type) then
1449 Error_Attr_P ("prefix of % attribute must be real type");
1451 end Check_Real_Type;
1453 -----------------------
1454 -- Check_Scalar_Type --
1455 -----------------------
1457 procedure Check_Scalar_Type is
1461 if not Is_Scalar_Type (P_Type) then
1462 Error_Attr_P ("prefix of % attribute must be scalar type");
1464 end Check_Scalar_Type;
1466 ---------------------------
1467 -- Check_Standard_Prefix --
1468 ---------------------------
1470 procedure Check_Standard_Prefix is
1474 if Nkind (P) /= N_Identifier
1475 or else Chars (P) /= Name_Standard
1477 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1479 end Check_Standard_Prefix;
1481 ----------------------------
1482 -- Check_Stream_Attribute --
1483 ----------------------------
1485 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1489 In_Shared_Var_Procs : Boolean;
1490 -- True when compiling the body of System.Shared_Storage.
1491 -- Shared_Var_Procs. For this runtime package (always compiled in
1492 -- GNAT mode), we allow stream attributes references for limited
1493 -- types for the case where shared passive objects are implemented
1494 -- using stream attributes, which is the default in GNAT's persistent
1495 -- storage implementation.
1498 Validate_Non_Static_Attribute_Function_Call;
1500 -- With the exception of 'Input, Stream attributes are procedures,
1501 -- and can only appear at the position of procedure calls. We check
1502 -- for this here, before they are rewritten, to give a more precise
1505 if Nam = TSS_Stream_Input then
1508 elsif Is_List_Member (N)
1509 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
1516 ("invalid context for attribute%, which is a procedure", N);
1520 Btyp := Implementation_Base_Type (P_Type);
1522 -- Stream attributes not allowed on limited types unless the
1523 -- attribute reference was generated by the expander (in which
1524 -- case the underlying type will be used, as described in Sinfo),
1525 -- or the attribute was specified explicitly for the type itself
1526 -- or one of its ancestors (taking visibility rules into account if
1527 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
1528 -- (with no visibility restriction).
1531 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
1533 if Present (Gen_Body) then
1534 In_Shared_Var_Procs :=
1535 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
1537 In_Shared_Var_Procs := False;
1541 if (Comes_From_Source (N)
1542 and then not (In_Shared_Var_Procs or In_Instance))
1543 and then not Stream_Attribute_Available (P_Type, Nam)
1544 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
1546 Error_Msg_Name_1 := Aname;
1548 if Is_Limited_Type (P_Type) then
1550 ("limited type& has no% attribute", P, P_Type);
1551 Explain_Limited_Type (P_Type, P);
1554 ("attribute% for type& is not available", P, P_Type);
1558 -- Check for violation of restriction No_Stream_Attributes
1560 if Is_RTE (P_Type, RE_Exception_Id)
1562 Is_RTE (P_Type, RE_Exception_Occurrence)
1564 Check_Restriction (No_Exception_Registration, P);
1567 -- Here we must check that the first argument is an access type
1568 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1570 Analyze_And_Resolve (E1);
1573 -- Note: the double call to Root_Type here is needed because the
1574 -- root type of a class-wide type is the corresponding type (e.g.
1575 -- X for X'Class, and we really want to go to the root.)
1577 if not Is_Access_Type (Etyp)
1578 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1579 RTE (RE_Root_Stream_Type)
1582 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1585 -- Check that the second argument is of the right type if there is
1586 -- one (the Input attribute has only one argument so this is skipped)
1588 if Present (E2) then
1591 if Nam = TSS_Stream_Read
1592 and then not Is_OK_Variable_For_Out_Formal (E2)
1595 ("second argument of % attribute must be a variable", E2);
1598 Resolve (E2, P_Type);
1602 end Check_Stream_Attribute;
1604 -----------------------
1605 -- Check_Task_Prefix --
1606 -----------------------
1608 procedure Check_Task_Prefix is
1612 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1613 -- task interface class-wide types.
1615 if Is_Task_Type (Etype (P))
1616 or else (Is_Access_Type (Etype (P))
1617 and then Is_Task_Type (Designated_Type (Etype (P))))
1618 or else (Ada_Version >= Ada_05
1619 and then Ekind (Etype (P)) = E_Class_Wide_Type
1620 and then Is_Interface (Etype (P))
1621 and then Is_Task_Interface (Etype (P)))
1626 if Ada_Version >= Ada_05 then
1628 ("prefix of % attribute must be a task or a task " &
1629 "interface class-wide object");
1632 Error_Attr_P ("prefix of % attribute must be a task");
1635 end Check_Task_Prefix;
1641 -- The possibilities are an entity name denoting a type, or an
1642 -- attribute reference that denotes a type (Base or Class). If
1643 -- the type is incomplete, replace it with its full view.
1645 procedure Check_Type is
1647 if not Is_Entity_Name (P)
1648 or else not Is_Type (Entity (P))
1650 Error_Attr_P ("prefix of % attribute must be a type");
1652 elsif Is_Protected_Self_Reference (P) then
1654 ("prefix of % attribute denotes current instance " &
1657 elsif Ekind (Entity (P)) = E_Incomplete_Type
1658 and then Present (Full_View (Entity (P)))
1660 P_Type := Full_View (Entity (P));
1661 Set_Entity (P, P_Type);
1665 ---------------------
1666 -- Check_Unit_Name --
1667 ---------------------
1669 procedure Check_Unit_Name (Nod : Node_Id) is
1671 if Nkind (Nod) = N_Identifier then
1674 elsif Nkind (Nod) = N_Selected_Component then
1675 Check_Unit_Name (Prefix (Nod));
1677 if Nkind (Selector_Name (Nod)) = N_Identifier then
1682 Error_Attr ("argument for % attribute must be unit name", P);
1683 end Check_Unit_Name;
1689 procedure Error_Attr is
1691 Set_Etype (N, Any_Type);
1692 Set_Entity (N, Any_Type);
1693 raise Bad_Attribute;
1696 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1698 Error_Msg_Name_1 := Aname;
1699 Error_Msg_N (Msg, Error_Node);
1707 procedure Error_Attr_P (Msg : String) is
1709 Error_Msg_Name_1 := Aname;
1710 Error_Msg_F (Msg, P);
1714 ----------------------------
1715 -- Legal_Formal_Attribute --
1716 ----------------------------
1718 procedure Legal_Formal_Attribute is
1722 if not Is_Entity_Name (P)
1723 or else not Is_Type (Entity (P))
1725 Error_Attr_P ("prefix of % attribute must be generic type");
1727 elsif Is_Generic_Actual_Type (Entity (P))
1729 or else In_Inlined_Body
1733 elsif Is_Generic_Type (Entity (P)) then
1734 if not Is_Indefinite_Subtype (Entity (P)) then
1736 ("prefix of % attribute must be indefinite generic type");
1741 ("prefix of % attribute must be indefinite generic type");
1744 Set_Etype (N, Standard_Boolean);
1745 end Legal_Formal_Attribute;
1747 ------------------------
1748 -- Standard_Attribute --
1749 ------------------------
1751 procedure Standard_Attribute (Val : Int) is
1753 Check_Standard_Prefix;
1754 Rewrite (N, Make_Integer_Literal (Loc, Val));
1756 end Standard_Attribute;
1758 -------------------------
1759 -- Unexpected Argument --
1760 -------------------------
1762 procedure Unexpected_Argument (En : Node_Id) is
1764 Error_Attr ("unexpected argument for % attribute", En);
1765 end Unexpected_Argument;
1767 -------------------------------------------------
1768 -- Validate_Non_Static_Attribute_Function_Call --
1769 -------------------------------------------------
1771 -- This function should be moved to Sem_Dist ???
1773 procedure Validate_Non_Static_Attribute_Function_Call is
1775 if In_Preelaborated_Unit
1776 and then not In_Subprogram_Or_Concurrent_Unit
1778 Flag_Non_Static_Expr
1779 ("non-static function call in preelaborated unit!", N);
1781 end Validate_Non_Static_Attribute_Function_Call;
1783 -----------------------------------------------
1784 -- Start of Processing for Analyze_Attribute --
1785 -----------------------------------------------
1788 -- Immediate return if unrecognized attribute (already diagnosed
1789 -- by parser, so there is nothing more that we need to do)
1791 if not Is_Attribute_Name (Aname) then
1792 raise Bad_Attribute;
1795 -- Deal with Ada 83 issues
1797 if Comes_From_Source (N) then
1798 if not Attribute_83 (Attr_Id) then
1799 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1800 Error_Msg_Name_1 := Aname;
1801 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1804 if Attribute_Impl_Def (Attr_Id) then
1805 Check_Restriction (No_Implementation_Attributes, N);
1810 -- Deal with Ada 2005 issues
1812 if Attribute_05 (Attr_Id) and then Ada_Version <= Ada_95 then
1813 Check_Restriction (No_Implementation_Attributes, N);
1816 -- Remote access to subprogram type access attribute reference needs
1817 -- unanalyzed copy for tree transformation. The analyzed copy is used
1818 -- for its semantic information (whether prefix is a remote subprogram
1819 -- name), the unanalyzed copy is used to construct new subtree rooted
1820 -- with N_Aggregate which represents a fat pointer aggregate.
1822 if Aname = Name_Access then
1823 Discard_Node (Copy_Separate_Tree (N));
1826 -- Analyze prefix and exit if error in analysis. If the prefix is an
1827 -- incomplete type, use full view if available. Note that there are
1828 -- some attributes for which we do not analyze the prefix, since the
1829 -- prefix is not a normal name.
1831 if Aname /= Name_Elab_Body
1833 Aname /= Name_Elab_Spec
1835 Aname /= Name_UET_Address
1837 Aname /= Name_Enabled
1840 P_Type := Etype (P);
1842 if Is_Entity_Name (P)
1843 and then Present (Entity (P))
1844 and then Is_Type (Entity (P))
1846 if Ekind (Entity (P)) = E_Incomplete_Type then
1847 P_Type := Get_Full_View (P_Type);
1848 Set_Entity (P, P_Type);
1849 Set_Etype (P, P_Type);
1851 elsif Entity (P) = Current_Scope
1852 and then Is_Record_Type (Entity (P))
1854 -- Use of current instance within the type. Verify that if the
1855 -- attribute appears within a constraint, it yields an access
1856 -- type, other uses are illegal.
1864 and then Nkind (Parent (Par)) /= N_Component_Definition
1866 Par := Parent (Par);
1870 and then Nkind (Par) = N_Subtype_Indication
1872 if Attr_Id /= Attribute_Access
1873 and then Attr_Id /= Attribute_Unchecked_Access
1874 and then Attr_Id /= Attribute_Unrestricted_Access
1877 ("in a constraint the current instance can only"
1878 & " be used with an access attribute", N);
1885 if P_Type = Any_Type then
1886 raise Bad_Attribute;
1889 P_Base_Type := Base_Type (P_Type);
1892 -- Analyze expressions that may be present, exiting if an error occurs
1899 E1 := First (Exprs);
1902 -- Check for missing/bad expression (result of previous error)
1904 if No (E1) or else Etype (E1) = Any_Type then
1905 raise Bad_Attribute;
1910 if Present (E2) then
1913 if Etype (E2) = Any_Type then
1914 raise Bad_Attribute;
1917 if Present (Next (E2)) then
1918 Unexpected_Argument (Next (E2));
1923 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
1924 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
1926 if Ada_Version < Ada_05
1927 and then Is_Overloaded (P)
1928 and then Aname /= Name_Access
1929 and then Aname /= Name_Address
1930 and then Aname /= Name_Code_Address
1931 and then Aname /= Name_Count
1932 and then Aname /= Name_Result
1933 and then Aname /= Name_Unchecked_Access
1935 Error_Attr ("ambiguous prefix for % attribute", P);
1937 elsif Ada_Version >= Ada_05
1938 and then Is_Overloaded (P)
1939 and then Aname /= Name_Access
1940 and then Aname /= Name_Address
1941 and then Aname /= Name_Code_Address
1942 and then Aname /= Name_Result
1943 and then Aname /= Name_Unchecked_Access
1945 -- Ada 2005 (AI-345): Since protected and task types have primitive
1946 -- entry wrappers, the attributes Count, Caller and AST_Entry require
1949 if Aname = Name_Count
1950 or else Aname = Name_Caller
1951 or else Aname = Name_AST_Entry
1954 Count : Natural := 0;
1959 Get_First_Interp (P, I, It);
1960 while Present (It.Nam) loop
1961 if Comes_From_Source (It.Nam) then
1967 Get_Next_Interp (I, It);
1971 Error_Attr ("ambiguous prefix for % attribute", P);
1973 Set_Is_Overloaded (P, False);
1978 Error_Attr ("ambiguous prefix for % attribute", P);
1982 -- Remaining processing depends on attribute
1990 when Attribute_Abort_Signal =>
1991 Check_Standard_Prefix;
1993 New_Reference_To (Stand.Abort_Signal, Loc));
2000 when Attribute_Access =>
2001 Analyze_Access_Attribute;
2007 when Attribute_Address =>
2010 -- Check for some junk cases, where we have to allow the address
2011 -- attribute but it does not make much sense, so at least for now
2012 -- just replace with Null_Address.
2014 -- We also do this if the prefix is a reference to the AST_Entry
2015 -- attribute. If expansion is active, the attribute will be
2016 -- replaced by a function call, and address will work fine and
2017 -- get the proper value, but if expansion is not active, then
2018 -- the check here allows proper semantic analysis of the reference.
2020 -- An Address attribute created by expansion is legal even when it
2021 -- applies to other entity-denoting expressions.
2023 if Is_Protected_Self_Reference (P) then
2024 -- An Address attribute on a protected object self reference
2029 elsif Is_Entity_Name (P) then
2031 Ent : constant Entity_Id := Entity (P);
2034 if Is_Subprogram (Ent) then
2035 Set_Address_Taken (Ent);
2036 Kill_Current_Values (Ent);
2038 -- An Address attribute is accepted when generated by the
2039 -- compiler for dispatching operation, and an error is
2040 -- issued once the subprogram is frozen (to avoid confusing
2041 -- errors about implicit uses of Address in the dispatch
2042 -- table initialization).
2044 if Has_Pragma_Inline_Always (Entity (P))
2045 and then Comes_From_Source (P)
2048 ("prefix of % attribute cannot be Inline_Always" &
2052 elsif Is_Object (Ent)
2053 or else Ekind (Ent) = E_Label
2055 Set_Address_Taken (Ent);
2057 -- If we have an address of an object, and the attribute
2058 -- comes from source, then set the object as potentially
2059 -- source modified. We do this because the resulting address
2060 -- can potentially be used to modify the variable and we
2061 -- might not detect this, leading to some junk warnings.
2063 Set_Never_Set_In_Source (Ent, False);
2065 elsif (Is_Concurrent_Type (Etype (Ent))
2066 and then Etype (Ent) = Base_Type (Ent))
2067 or else Ekind (Ent) = E_Package
2068 or else Is_Generic_Unit (Ent)
2071 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2074 Error_Attr ("invalid prefix for % attribute", P);
2078 elsif Nkind (P) = N_Attribute_Reference
2079 and then Attribute_Name (P) = Name_AST_Entry
2082 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2084 elsif Is_Object_Reference (P) then
2087 elsif Nkind (P) = N_Selected_Component
2088 and then Is_Subprogram (Entity (Selector_Name (P)))
2092 -- What exactly are we allowing here ??? and is this properly
2093 -- documented in the sinfo documentation for this node ???
2095 elsif not Comes_From_Source (N) then
2099 Error_Attr ("invalid prefix for % attribute", P);
2102 Set_Etype (N, RTE (RE_Address));
2108 when Attribute_Address_Size =>
2109 Standard_Attribute (System_Address_Size);
2115 when Attribute_Adjacent =>
2116 Check_Floating_Point_Type_2;
2117 Set_Etype (N, P_Base_Type);
2118 Resolve (E1, P_Base_Type);
2119 Resolve (E2, P_Base_Type);
2125 when Attribute_Aft =>
2126 Check_Fixed_Point_Type_0;
2127 Set_Etype (N, Universal_Integer);
2133 when Attribute_Alignment =>
2135 -- Don't we need more checking here, cf Size ???
2138 Check_Not_Incomplete_Type;
2140 Set_Etype (N, Universal_Integer);
2146 when Attribute_Asm_Input =>
2147 Check_Asm_Attribute;
2148 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2154 when Attribute_Asm_Output =>
2155 Check_Asm_Attribute;
2157 if Etype (E2) = Any_Type then
2160 elsif Aname = Name_Asm_Output then
2161 if not Is_Variable (E2) then
2163 ("second argument for Asm_Output is not variable", E2);
2167 Note_Possible_Modification (E2, Sure => True);
2168 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2174 when Attribute_AST_Entry => AST_Entry : declare
2180 -- Indicates if entry family index is present. Note the coding
2181 -- here handles the entry family case, but in fact it cannot be
2182 -- executed currently, because pragma AST_Entry does not permit
2183 -- the specification of an entry family.
2185 procedure Bad_AST_Entry;
2186 -- Signal a bad AST_Entry pragma
2188 function OK_Entry (E : Entity_Id) return Boolean;
2189 -- Checks that E is of an appropriate entity kind for an entry
2190 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2191 -- is set True for the entry family case). In the True case,
2192 -- makes sure that Is_AST_Entry is set on the entry.
2198 procedure Bad_AST_Entry is
2200 Error_Attr_P ("prefix for % attribute must be task entry");
2207 function OK_Entry (E : Entity_Id) return Boolean is
2212 Result := (Ekind (E) = E_Entry_Family);
2214 Result := (Ekind (E) = E_Entry);
2218 if not Is_AST_Entry (E) then
2219 Error_Msg_Name_2 := Aname;
2220 Error_Attr ("% attribute requires previous % pragma", P);
2227 -- Start of processing for AST_Entry
2233 -- Deal with entry family case
2235 if Nkind (P) = N_Indexed_Component then
2243 Ptyp := Etype (Pref);
2245 if Ptyp = Any_Type or else Error_Posted (Pref) then
2249 -- If the prefix is a selected component whose prefix is of an
2250 -- access type, then introduce an explicit dereference.
2251 -- ??? Could we reuse Check_Dereference here?
2253 if Nkind (Pref) = N_Selected_Component
2254 and then Is_Access_Type (Ptyp)
2257 Make_Explicit_Dereference (Sloc (Pref),
2258 Relocate_Node (Pref)));
2259 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2262 -- Prefix can be of the form a.b, where a is a task object
2263 -- and b is one of the entries of the corresponding task type.
2265 if Nkind (Pref) = N_Selected_Component
2266 and then OK_Entry (Entity (Selector_Name (Pref)))
2267 and then Is_Object_Reference (Prefix (Pref))
2268 and then Is_Task_Type (Etype (Prefix (Pref)))
2272 -- Otherwise the prefix must be an entry of a containing task,
2273 -- or of a variable of the enclosing task type.
2276 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2277 Ent := Entity (Pref);
2279 if not OK_Entry (Ent)
2280 or else not In_Open_Scopes (Scope (Ent))
2290 Set_Etype (N, RTE (RE_AST_Handler));
2297 -- Note: when the base attribute appears in the context of a subtype
2298 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2299 -- the following circuit.
2301 when Attribute_Base => Base : declare
2309 if Ada_Version >= Ada_95
2310 and then not Is_Scalar_Type (Typ)
2311 and then not Is_Generic_Type (Typ)
2313 Error_Attr_P ("prefix of Base attribute must be scalar type");
2315 elsif Sloc (Typ) = Standard_Location
2316 and then Base_Type (Typ) = Typ
2317 and then Warn_On_Redundant_Constructs
2320 ("?redundant attribute, & is its own base type", N, Typ);
2323 Set_Etype (N, Base_Type (Entity (P)));
2324 Set_Entity (N, Base_Type (Entity (P)));
2325 Rewrite (N, New_Reference_To (Entity (N), Loc));
2333 when Attribute_Bit => Bit :
2337 if not Is_Object_Reference (P) then
2338 Error_Attr_P ("prefix for % attribute must be object");
2340 -- What about the access object cases ???
2346 Set_Etype (N, Universal_Integer);
2353 when Attribute_Bit_Order => Bit_Order :
2358 if not Is_Record_Type (P_Type) then
2359 Error_Attr_P ("prefix of % attribute must be record type");
2362 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2364 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2367 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2370 Set_Etype (N, RTE (RE_Bit_Order));
2373 -- Reset incorrect indication of staticness
2375 Set_Is_Static_Expression (N, False);
2382 -- Note: in generated code, we can have a Bit_Position attribute
2383 -- applied to a (naked) record component (i.e. the prefix is an
2384 -- identifier that references an E_Component or E_Discriminant
2385 -- entity directly, and this is interpreted as expected by Gigi.
2386 -- The following code will not tolerate such usage, but when the
2387 -- expander creates this special case, it marks it as analyzed
2388 -- immediately and sets an appropriate type.
2390 when Attribute_Bit_Position =>
2391 if Comes_From_Source (N) then
2395 Set_Etype (N, Universal_Integer);
2401 when Attribute_Body_Version =>
2404 Set_Etype (N, RTE (RE_Version_String));
2410 when Attribute_Callable =>
2412 Set_Etype (N, Standard_Boolean);
2419 when Attribute_Caller => Caller : declare
2426 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2429 if not Is_Entry (Ent) then
2430 Error_Attr ("invalid entry name", N);
2434 Error_Attr ("invalid entry name", N);
2438 for J in reverse 0 .. Scope_Stack.Last loop
2439 S := Scope_Stack.Table (J).Entity;
2441 if S = Scope (Ent) then
2442 Error_Attr ("Caller must appear in matching accept or body", N);
2448 Set_Etype (N, RTE (RO_AT_Task_Id));
2455 when Attribute_Ceiling =>
2456 Check_Floating_Point_Type_1;
2457 Set_Etype (N, P_Base_Type);
2458 Resolve (E1, P_Base_Type);
2464 when Attribute_Class =>
2465 Check_Restriction (No_Dispatch, N);
2473 when Attribute_Code_Address =>
2476 if Nkind (P) = N_Attribute_Reference
2477 and then (Attribute_Name (P) = Name_Elab_Body
2479 Attribute_Name (P) = Name_Elab_Spec)
2483 elsif not Is_Entity_Name (P)
2484 or else (Ekind (Entity (P)) /= E_Function
2486 Ekind (Entity (P)) /= E_Procedure)
2488 Error_Attr ("invalid prefix for % attribute", P);
2489 Set_Address_Taken (Entity (P));
2492 Set_Etype (N, RTE (RE_Address));
2494 --------------------
2495 -- Component_Size --
2496 --------------------
2498 when Attribute_Component_Size =>
2500 Set_Etype (N, Universal_Integer);
2502 -- Note: unlike other array attributes, unconstrained arrays are OK
2504 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2514 when Attribute_Compose =>
2515 Check_Floating_Point_Type_2;
2516 Set_Etype (N, P_Base_Type);
2517 Resolve (E1, P_Base_Type);
2518 Resolve (E2, Any_Integer);
2524 when Attribute_Constrained =>
2526 Set_Etype (N, Standard_Boolean);
2528 -- Case from RM J.4(2) of constrained applied to private type
2530 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2531 Check_Restriction (No_Obsolescent_Features, N);
2533 if Warn_On_Obsolescent_Feature then
2535 ("constrained for private type is an " &
2536 "obsolescent feature (RM J.4)?", N);
2539 -- If we are within an instance, the attribute must be legal
2540 -- because it was valid in the generic unit. Ditto if this is
2541 -- an inlining of a function declared in an instance.
2544 or else In_Inlined_Body
2548 -- For sure OK if we have a real private type itself, but must
2549 -- be completed, cannot apply Constrained to incomplete type.
2551 elsif Is_Private_Type (Entity (P)) then
2553 -- Note: this is one of the Annex J features that does not
2554 -- generate a warning from -gnatwj, since in fact it seems
2555 -- very useful, and is used in the GNAT runtime.
2557 Check_Not_Incomplete_Type;
2561 -- Normal (non-obsolescent case) of application to object of
2562 -- a discriminated type.
2565 Check_Object_Reference (P);
2567 -- If N does not come from source, then we allow the
2568 -- the attribute prefix to be of a private type whose
2569 -- full type has discriminants. This occurs in cases
2570 -- involving expanded calls to stream attributes.
2572 if not Comes_From_Source (N) then
2573 P_Type := Underlying_Type (P_Type);
2576 -- Must have discriminants or be an access type designating
2577 -- a type with discriminants. If it is a classwide type is ???
2578 -- has unknown discriminants.
2580 if Has_Discriminants (P_Type)
2581 or else Has_Unknown_Discriminants (P_Type)
2583 (Is_Access_Type (P_Type)
2584 and then Has_Discriminants (Designated_Type (P_Type)))
2588 -- Also allow an object of a generic type if extensions allowed
2589 -- and allow this for any type at all.
2591 elsif (Is_Generic_Type (P_Type)
2592 or else Is_Generic_Actual_Type (P_Type))
2593 and then Extensions_Allowed
2599 -- Fall through if bad prefix
2602 ("prefix of % attribute must be object of discriminated type");
2608 when Attribute_Copy_Sign =>
2609 Check_Floating_Point_Type_2;
2610 Set_Etype (N, P_Base_Type);
2611 Resolve (E1, P_Base_Type);
2612 Resolve (E2, P_Base_Type);
2618 when Attribute_Count => Count :
2627 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2630 if Ekind (Ent) /= E_Entry then
2631 Error_Attr ("invalid entry name", N);
2634 elsif Nkind (P) = N_Indexed_Component then
2635 if not Is_Entity_Name (Prefix (P))
2636 or else No (Entity (Prefix (P)))
2637 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2639 if Nkind (Prefix (P)) = N_Selected_Component
2640 and then Present (Entity (Selector_Name (Prefix (P))))
2641 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2645 ("attribute % must apply to entry of current task", P);
2648 Error_Attr ("invalid entry family name", P);
2653 Ent := Entity (Prefix (P));
2656 elsif Nkind (P) = N_Selected_Component
2657 and then Present (Entity (Selector_Name (P)))
2658 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2661 ("attribute % must apply to entry of current task", P);
2664 Error_Attr ("invalid entry name", N);
2668 for J in reverse 0 .. Scope_Stack.Last loop
2669 S := Scope_Stack.Table (J).Entity;
2671 if S = Scope (Ent) then
2672 if Nkind (P) = N_Expanded_Name then
2673 Tsk := Entity (Prefix (P));
2675 -- The prefix denotes either the task type, or else a
2676 -- single task whose task type is being analyzed.
2681 or else (not Is_Type (Tsk)
2682 and then Etype (Tsk) = S
2683 and then not (Comes_From_Source (S)))
2688 ("Attribute % must apply to entry of current task", N);
2694 elsif Ekind (Scope (Ent)) in Task_Kind
2695 and then Ekind (S) /= E_Loop
2696 and then Ekind (S) /= E_Block
2697 and then Ekind (S) /= E_Entry
2698 and then Ekind (S) /= E_Entry_Family
2700 Error_Attr ("Attribute % cannot appear in inner unit", N);
2702 elsif Ekind (Scope (Ent)) = E_Protected_Type
2703 and then not Has_Completion (Scope (Ent))
2705 Error_Attr ("attribute % can only be used inside body", N);
2709 if Is_Overloaded (P) then
2711 Index : Interp_Index;
2715 Get_First_Interp (P, Index, It);
2717 while Present (It.Nam) loop
2718 if It.Nam = Ent then
2721 -- Ada 2005 (AI-345): Do not consider primitive entry
2722 -- wrappers generated for task or protected types.
2724 elsif Ada_Version >= Ada_05
2725 and then not Comes_From_Source (It.Nam)
2730 Error_Attr ("ambiguous entry name", N);
2733 Get_Next_Interp (Index, It);
2738 Set_Etype (N, Universal_Integer);
2741 -----------------------
2742 -- Default_Bit_Order --
2743 -----------------------
2745 when Attribute_Default_Bit_Order => Default_Bit_Order :
2747 Check_Standard_Prefix;
2749 if Bytes_Big_Endian then
2751 Make_Integer_Literal (Loc, False_Value));
2754 Make_Integer_Literal (Loc, True_Value));
2757 Set_Etype (N, Universal_Integer);
2758 Set_Is_Static_Expression (N);
2759 end Default_Bit_Order;
2765 when Attribute_Definite =>
2766 Legal_Formal_Attribute;
2772 when Attribute_Delta =>
2773 Check_Fixed_Point_Type_0;
2774 Set_Etype (N, Universal_Real);
2780 when Attribute_Denorm =>
2781 Check_Floating_Point_Type_0;
2782 Set_Etype (N, Standard_Boolean);
2788 when Attribute_Digits =>
2792 if not Is_Floating_Point_Type (P_Type)
2793 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2796 ("prefix of % attribute must be float or decimal type");
2799 Set_Etype (N, Universal_Integer);
2805 -- Also handles processing for Elab_Spec
2807 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2809 Check_Unit_Name (P);
2810 Set_Etype (N, Standard_Void_Type);
2812 -- We have to manually call the expander in this case to get
2813 -- the necessary expansion (normally attributes that return
2814 -- entities are not expanded).
2822 -- Shares processing with Elab_Body
2828 when Attribute_Elaborated =>
2831 Set_Etype (N, Standard_Boolean);
2837 when Attribute_Emax =>
2838 Check_Floating_Point_Type_0;
2839 Set_Etype (N, Universal_Integer);
2845 when Attribute_Enabled =>
2846 Check_Either_E0_Or_E1;
2848 if Present (E1) then
2849 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
2850 Error_Msg_N ("entity name expected for Enabled attribute", E1);
2855 if Nkind (P) /= N_Identifier then
2856 Error_Msg_N ("identifier expected (check name)", P);
2857 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
2858 Error_Msg_N ("& is not a recognized check name", P);
2861 Set_Etype (N, Standard_Boolean);
2867 when Attribute_Enum_Rep => Enum_Rep : declare
2869 if Present (E1) then
2871 Check_Discrete_Type;
2872 Resolve (E1, P_Base_Type);
2875 if not Is_Entity_Name (P)
2876 or else (not Is_Object (Entity (P))
2878 Ekind (Entity (P)) /= E_Enumeration_Literal)
2881 ("prefix of %attribute must be " &
2882 "discrete type/object or enum literal");
2886 Set_Etype (N, Universal_Integer);
2893 when Attribute_Enum_Val => Enum_Val : begin
2897 if not Is_Enumeration_Type (P_Type) then
2898 Error_Attr_P ("prefix of % attribute must be enumeration type");
2901 -- If the enumeration type has a standard representation, the effect
2902 -- is the same as 'Val, so rewrite the attribute as a 'Val.
2904 if not Has_Non_Standard_Rep (P_Base_Type) then
2906 Make_Attribute_Reference (Loc,
2907 Prefix => Relocate_Node (Prefix (N)),
2908 Attribute_Name => Name_Val,
2909 Expressions => New_List (Relocate_Node (E1))));
2910 Analyze_And_Resolve (N, P_Base_Type);
2912 -- Non-standard representation case (enumeration with holes)
2916 Resolve (E1, Any_Integer);
2917 Set_Etype (N, P_Base_Type);
2925 when Attribute_Epsilon =>
2926 Check_Floating_Point_Type_0;
2927 Set_Etype (N, Universal_Real);
2933 when Attribute_Exponent =>
2934 Check_Floating_Point_Type_1;
2935 Set_Etype (N, Universal_Integer);
2936 Resolve (E1, P_Base_Type);
2942 when Attribute_External_Tag =>
2946 Set_Etype (N, Standard_String);
2948 if not Is_Tagged_Type (P_Type) then
2949 Error_Attr_P ("prefix of % attribute must be tagged");
2956 when Attribute_Fast_Math =>
2957 Check_Standard_Prefix;
2959 if Opt.Fast_Math then
2960 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
2962 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
2969 when Attribute_First =>
2970 Check_Array_Or_Scalar_Type;
2976 when Attribute_First_Bit =>
2978 Set_Etype (N, Universal_Integer);
2984 when Attribute_Fixed_Value =>
2986 Check_Fixed_Point_Type;
2987 Resolve (E1, Any_Integer);
2988 Set_Etype (N, P_Base_Type);
2994 when Attribute_Floor =>
2995 Check_Floating_Point_Type_1;
2996 Set_Etype (N, P_Base_Type);
2997 Resolve (E1, P_Base_Type);
3003 when Attribute_Fore =>
3004 Check_Fixed_Point_Type_0;
3005 Set_Etype (N, Universal_Integer);
3011 when Attribute_Fraction =>
3012 Check_Floating_Point_Type_1;
3013 Set_Etype (N, P_Base_Type);
3014 Resolve (E1, P_Base_Type);
3020 when Attribute_From_Any =>
3022 Check_PolyORB_Attribute;
3023 Set_Etype (N, P_Base_Type);
3025 -----------------------
3026 -- Has_Access_Values --
3027 -----------------------
3029 when Attribute_Has_Access_Values =>
3032 Set_Etype (N, Standard_Boolean);
3034 -----------------------
3035 -- Has_Tagged_Values --
3036 -----------------------
3038 when Attribute_Has_Tagged_Values =>
3041 Set_Etype (N, Standard_Boolean);
3043 -----------------------
3044 -- Has_Discriminants --
3045 -----------------------
3047 when Attribute_Has_Discriminants =>
3048 Legal_Formal_Attribute;
3054 when Attribute_Identity =>
3058 if Etype (P) = Standard_Exception_Type then
3059 Set_Etype (N, RTE (RE_Exception_Id));
3061 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3062 -- task interface class-wide types.
3064 elsif Is_Task_Type (Etype (P))
3065 or else (Is_Access_Type (Etype (P))
3066 and then Is_Task_Type (Designated_Type (Etype (P))))
3067 or else (Ada_Version >= Ada_05
3068 and then Ekind (Etype (P)) = E_Class_Wide_Type
3069 and then Is_Interface (Etype (P))
3070 and then Is_Task_Interface (Etype (P)))
3073 Set_Etype (N, RTE (RO_AT_Task_Id));
3076 if Ada_Version >= Ada_05 then
3078 ("prefix of % attribute must be an exception, a " &
3079 "task or a task interface class-wide object");
3082 ("prefix of % attribute must be a task or an exception");
3090 when Attribute_Image => Image :
3092 Set_Etype (N, Standard_String);
3095 if Is_Real_Type (P_Type) then
3096 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3097 Error_Msg_Name_1 := Aname;
3099 ("(Ada 83) % attribute not allowed for real types", N);
3103 if Is_Enumeration_Type (P_Type) then
3104 Check_Restriction (No_Enumeration_Maps, N);
3108 Resolve (E1, P_Base_Type);
3110 Validate_Non_Static_Attribute_Function_Call;
3117 when Attribute_Img => Img :
3120 Set_Etype (N, Standard_String);
3122 if not Is_Scalar_Type (P_Type)
3123 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3126 ("prefix of % attribute must be scalar object name");
3136 when Attribute_Input =>
3138 Check_Stream_Attribute (TSS_Stream_Input);
3139 Set_Etype (N, P_Base_Type);
3145 when Attribute_Integer_Value =>
3148 Resolve (E1, Any_Fixed);
3150 -- Signal an error if argument type is not a specific fixed-point
3151 -- subtype. An error has been signalled already if the argument
3152 -- was not of a fixed-point type.
3154 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3155 Error_Attr ("argument of % must be of a fixed-point type", E1);
3158 Set_Etype (N, P_Base_Type);
3164 when Attribute_Invalid_Value =>
3167 Set_Etype (N, P_Base_Type);
3168 Invalid_Value_Used := True;
3174 when Attribute_Large =>
3177 Set_Etype (N, Universal_Real);
3183 when Attribute_Last =>
3184 Check_Array_Or_Scalar_Type;
3190 when Attribute_Last_Bit =>
3192 Set_Etype (N, Universal_Integer);
3198 when Attribute_Leading_Part =>
3199 Check_Floating_Point_Type_2;
3200 Set_Etype (N, P_Base_Type);
3201 Resolve (E1, P_Base_Type);
3202 Resolve (E2, Any_Integer);
3208 when Attribute_Length =>
3210 Set_Etype (N, Universal_Integer);
3216 when Attribute_Machine =>
3217 Check_Floating_Point_Type_1;
3218 Set_Etype (N, P_Base_Type);
3219 Resolve (E1, P_Base_Type);
3225 when Attribute_Machine_Emax =>
3226 Check_Floating_Point_Type_0;
3227 Set_Etype (N, Universal_Integer);
3233 when Attribute_Machine_Emin =>
3234 Check_Floating_Point_Type_0;
3235 Set_Etype (N, Universal_Integer);
3237 ----------------------
3238 -- Machine_Mantissa --
3239 ----------------------
3241 when Attribute_Machine_Mantissa =>
3242 Check_Floating_Point_Type_0;
3243 Set_Etype (N, Universal_Integer);
3245 -----------------------
3246 -- Machine_Overflows --
3247 -----------------------
3249 when Attribute_Machine_Overflows =>
3252 Set_Etype (N, Standard_Boolean);
3258 when Attribute_Machine_Radix =>
3261 Set_Etype (N, Universal_Integer);
3263 ----------------------
3264 -- Machine_Rounding --
3265 ----------------------
3267 when Attribute_Machine_Rounding =>
3268 Check_Floating_Point_Type_1;
3269 Set_Etype (N, P_Base_Type);
3270 Resolve (E1, P_Base_Type);
3272 --------------------
3273 -- Machine_Rounds --
3274 --------------------
3276 when Attribute_Machine_Rounds =>
3279 Set_Etype (N, Standard_Boolean);
3285 when Attribute_Machine_Size =>
3288 Check_Not_Incomplete_Type;
3289 Set_Etype (N, Universal_Integer);
3295 when Attribute_Mantissa =>
3298 Set_Etype (N, Universal_Integer);
3304 when Attribute_Max =>
3307 Resolve (E1, P_Base_Type);
3308 Resolve (E2, P_Base_Type);
3309 Set_Etype (N, P_Base_Type);
3311 ----------------------------------
3312 -- Max_Size_In_Storage_Elements --
3313 ----------------------------------
3315 when Attribute_Max_Size_In_Storage_Elements =>
3318 Check_Not_Incomplete_Type;
3319 Set_Etype (N, Universal_Integer);
3321 -----------------------
3322 -- Maximum_Alignment --
3323 -----------------------
3325 when Attribute_Maximum_Alignment =>
3326 Standard_Attribute (Ttypes.Maximum_Alignment);
3328 --------------------
3329 -- Mechanism_Code --
3330 --------------------
3332 when Attribute_Mechanism_Code =>
3333 if not Is_Entity_Name (P)
3334 or else not Is_Subprogram (Entity (P))
3336 Error_Attr_P ("prefix of % attribute must be subprogram");
3339 Check_Either_E0_Or_E1;
3341 if Present (E1) then
3342 Resolve (E1, Any_Integer);
3343 Set_Etype (E1, Standard_Integer);
3345 if not Is_Static_Expression (E1) then
3346 Flag_Non_Static_Expr
3347 ("expression for parameter number must be static!", E1);
3350 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3351 or else UI_To_Int (Intval (E1)) < 0
3353 Error_Attr ("invalid parameter number for %attribute", E1);
3357 Set_Etype (N, Universal_Integer);
3363 when Attribute_Min =>
3366 Resolve (E1, P_Base_Type);
3367 Resolve (E2, P_Base_Type);
3368 Set_Etype (N, P_Base_Type);
3374 when Attribute_Mod =>
3376 -- Note: this attribute is only allowed in Ada 2005 mode, but
3377 -- we do not need to test that here, since Mod is only recognized
3378 -- as an attribute name in Ada 2005 mode during the parse.
3381 Check_Modular_Integer_Type;
3382 Resolve (E1, Any_Integer);
3383 Set_Etype (N, P_Base_Type);
3389 when Attribute_Model =>
3390 Check_Floating_Point_Type_1;
3391 Set_Etype (N, P_Base_Type);
3392 Resolve (E1, P_Base_Type);
3398 when Attribute_Model_Emin =>
3399 Check_Floating_Point_Type_0;
3400 Set_Etype (N, Universal_Integer);
3406 when Attribute_Model_Epsilon =>
3407 Check_Floating_Point_Type_0;
3408 Set_Etype (N, Universal_Real);
3410 --------------------
3411 -- Model_Mantissa --
3412 --------------------
3414 when Attribute_Model_Mantissa =>
3415 Check_Floating_Point_Type_0;
3416 Set_Etype (N, Universal_Integer);
3422 when Attribute_Model_Small =>
3423 Check_Floating_Point_Type_0;
3424 Set_Etype (N, Universal_Real);
3430 when Attribute_Modulus =>
3432 Check_Modular_Integer_Type;
3433 Set_Etype (N, Universal_Integer);
3435 --------------------
3436 -- Null_Parameter --
3437 --------------------
3439 when Attribute_Null_Parameter => Null_Parameter : declare
3440 Parnt : constant Node_Id := Parent (N);
3441 GParnt : constant Node_Id := Parent (Parnt);
3443 procedure Bad_Null_Parameter (Msg : String);
3444 -- Used if bad Null parameter attribute node is found. Issues
3445 -- given error message, and also sets the type to Any_Type to
3446 -- avoid blowups later on from dealing with a junk node.
3448 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3449 -- Called to check that Proc_Ent is imported subprogram
3451 ------------------------
3452 -- Bad_Null_Parameter --
3453 ------------------------
3455 procedure Bad_Null_Parameter (Msg : String) is
3457 Error_Msg_N (Msg, N);
3458 Set_Etype (N, Any_Type);
3459 end Bad_Null_Parameter;
3461 ----------------------
3462 -- Must_Be_Imported --
3463 ----------------------
3465 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3466 Pent : Entity_Id := Proc_Ent;
3469 while Present (Alias (Pent)) loop
3470 Pent := Alias (Pent);
3473 -- Ignore check if procedure not frozen yet (we will get
3474 -- another chance when the default parameter is reanalyzed)
3476 if not Is_Frozen (Pent) then
3479 elsif not Is_Imported (Pent) then
3481 ("Null_Parameter can only be used with imported subprogram");
3486 end Must_Be_Imported;
3488 -- Start of processing for Null_Parameter
3493 Set_Etype (N, P_Type);
3495 -- Case of attribute used as default expression
3497 if Nkind (Parnt) = N_Parameter_Specification then
3498 Must_Be_Imported (Defining_Entity (GParnt));
3500 -- Case of attribute used as actual for subprogram (positional)
3502 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3504 and then Is_Entity_Name (Name (Parnt))
3506 Must_Be_Imported (Entity (Name (Parnt)));
3508 -- Case of attribute used as actual for subprogram (named)
3510 elsif Nkind (Parnt) = N_Parameter_Association
3511 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3513 and then Is_Entity_Name (Name (GParnt))
3515 Must_Be_Imported (Entity (Name (GParnt)));
3517 -- Not an allowed case
3521 ("Null_Parameter must be actual or default parameter");
3529 when Attribute_Object_Size =>
3532 Check_Not_Incomplete_Type;
3533 Set_Etype (N, Universal_Integer);
3539 when Attribute_Old =>
3541 Set_Etype (N, P_Type);
3543 if No (Current_Subprogram) then
3544 Error_Attr ("attribute % can only appear within subprogram", N);
3547 if Is_Limited_Type (P_Type) then
3548 Error_Attr ("attribute % cannot apply to limited objects", P);
3551 if Is_Entity_Name (P)
3552 and then Is_Constant_Object (Entity (P))
3555 ("?attribute Old applied to constant has no effect", P);
3558 -- Check that the expression does not refer to local entities
3560 Check_Local : declare
3561 Subp : Entity_Id := Current_Subprogram;
3563 function Process (N : Node_Id) return Traverse_Result;
3564 -- Check that N does not contain references to local variables
3565 -- or other local entities of Subp.
3571 function Process (N : Node_Id) return Traverse_Result is
3573 if Is_Entity_Name (N)
3574 and then not Is_Formal (Entity (N))
3575 and then Enclosing_Subprogram (Entity (N)) = Subp
3577 Error_Msg_Node_1 := Entity (N);
3579 ("attribute % cannot refer to local variable&", N);
3585 procedure Check_No_Local is new Traverse_Proc;
3587 -- Start of processing for Check_Local
3592 if In_Parameter_Specification (P) then
3594 -- We have additional restrictions on using 'Old in parameter
3597 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3599 -- Check that there is no reference to the enclosing
3600 -- subprogram local variables. Otherwise, we might end
3601 -- up being called from the enclosing subprogram and thus
3602 -- using 'Old on a local variable which is not defined
3605 Subp := Enclosing_Subprogram (Current_Subprogram);
3609 -- We must prevent default expression of library-level
3610 -- subprogram from using 'Old, as the subprogram may be
3611 -- used in elaboration code for which there is no enclosing
3615 ("attribute % can only appear within subprogram", N);
3624 when Attribute_Output =>
3626 Check_Stream_Attribute (TSS_Stream_Output);
3627 Set_Etype (N, Standard_Void_Type);
3628 Resolve (N, Standard_Void_Type);
3634 when Attribute_Partition_ID => Partition_Id :
3638 if P_Type /= Any_Type then
3639 if not Is_Library_Level_Entity (Entity (P)) then
3641 ("prefix of % attribute must be library-level entity");
3643 -- The defining entity of prefix should not be declared inside a
3644 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3646 elsif Is_Entity_Name (P)
3647 and then Is_Pure (Entity (P))
3650 ("prefix of % attribute must not be declared pure");
3654 Set_Etype (N, Universal_Integer);
3657 -------------------------
3658 -- Passed_By_Reference --
3659 -------------------------
3661 when Attribute_Passed_By_Reference =>
3664 Set_Etype (N, Standard_Boolean);
3670 when Attribute_Pool_Address =>
3672 Set_Etype (N, RTE (RE_Address));
3678 when Attribute_Pos =>
3679 Check_Discrete_Type;
3681 Resolve (E1, P_Base_Type);
3682 Set_Etype (N, Universal_Integer);
3688 when Attribute_Position =>
3690 Set_Etype (N, Universal_Integer);
3696 when Attribute_Pred =>
3699 Resolve (E1, P_Base_Type);
3700 Set_Etype (N, P_Base_Type);
3702 -- Nothing to do for real type case
3704 if Is_Real_Type (P_Type) then
3707 -- If not modular type, test for overflow check required
3710 if not Is_Modular_Integer_Type (P_Type)
3711 and then not Range_Checks_Suppressed (P_Base_Type)
3713 Enable_Range_Check (E1);
3721 -- Ada 2005 (AI-327): Dynamic ceiling priorities
3723 when Attribute_Priority =>
3724 if Ada_Version < Ada_05 then
3725 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
3730 -- The prefix must be a protected object (AARM D.5.2 (2/2))
3734 if Is_Protected_Type (Etype (P))
3735 or else (Is_Access_Type (Etype (P))
3736 and then Is_Protected_Type (Designated_Type (Etype (P))))
3738 Resolve (P, Etype (P));
3740 Error_Attr_P ("prefix of % attribute must be a protected object");
3743 Set_Etype (N, Standard_Integer);
3745 -- Must be called from within a protected procedure or entry of the
3746 -- protected object.
3753 while S /= Etype (P)
3754 and then S /= Standard_Standard
3759 if S = Standard_Standard then
3760 Error_Attr ("the attribute % is only allowed inside protected "
3765 Validate_Non_Static_Attribute_Function_Call;
3771 when Attribute_Range =>
3772 Check_Array_Or_Scalar_Type;
3774 if Ada_Version = Ada_83
3775 and then Is_Scalar_Type (P_Type)
3776 and then Comes_From_Source (N)
3779 ("(Ada 83) % attribute not allowed for scalar type", P);
3786 when Attribute_Result => Result : declare
3787 CS : Entity_Id := Current_Scope;
3788 PS : Entity_Id := Scope (CS);
3791 -- If the enclosing subprogram is always inlined, the enclosing
3792 -- postcondition will not be propagated to the expanded call.
3794 if Has_Pragma_Inline_Always (PS)
3795 and then Warn_On_Redundant_Constructs
3798 ("postconditions on inlined functions not enforced?", N);
3801 -- If we are in the scope of a function and in Spec_Expression mode,
3802 -- this is likely the prescan of the postcondition pragma, and we
3803 -- just set the proper type. If there is an error it will be caught
3804 -- when the real Analyze call is done.
3806 if Ekind (CS) = E_Function
3807 and then In_Spec_Expression
3811 if Chars (CS) /= Chars (P) then
3813 ("incorrect prefix for % attribute, expected &", P, CS);
3817 Set_Etype (N, Etype (CS));
3819 -- If several functions with that name are visible,
3820 -- the intended one is the current scope.
3822 if Is_Overloaded (P) then
3824 Set_Is_Overloaded (P, False);
3827 -- Body case, where we must be inside a generated _Postcondition
3828 -- procedure, and the prefix must be on the scope stack, or else
3829 -- the attribute use is definitely misplaced. The condition itself
3830 -- may have generated transient scopes, and is not necessarily the
3835 and then CS /= Standard_Standard
3837 if Chars (CS) = Name_uPostconditions then
3846 if Chars (CS) = Name_uPostconditions
3847 and then Ekind (PS) = E_Function
3851 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
3852 and then Chars (P) = Chars (PS)
3856 -- Within an instance, the prefix designates the local renaming
3857 -- of the original generic.
3859 elsif Is_Entity_Name (P)
3860 and then Ekind (Entity (P)) = E_Function
3861 and then Present (Alias (Entity (P)))
3862 and then Chars (Alias (Entity (P))) = Chars (PS)
3868 ("incorrect prefix for % attribute, expected &", P, PS);
3873 Make_Identifier (Sloc (N),
3874 Chars => Name_uResult));
3875 Analyze_And_Resolve (N, Etype (PS));
3879 ("% attribute can only appear" &
3880 " in function Postcondition pragma", P);
3889 when Attribute_Range_Length =>
3891 Check_Discrete_Type;
3892 Set_Etype (N, Universal_Integer);
3898 when Attribute_Read =>
3900 Check_Stream_Attribute (TSS_Stream_Read);
3901 Set_Etype (N, Standard_Void_Type);
3902 Resolve (N, Standard_Void_Type);
3903 Note_Possible_Modification (E2, Sure => True);
3909 when Attribute_Remainder =>
3910 Check_Floating_Point_Type_2;
3911 Set_Etype (N, P_Base_Type);
3912 Resolve (E1, P_Base_Type);
3913 Resolve (E2, P_Base_Type);
3919 when Attribute_Round =>
3921 Check_Decimal_Fixed_Point_Type;
3922 Set_Etype (N, P_Base_Type);
3924 -- Because the context is universal_real (3.5.10(12)) it is a legal
3925 -- context for a universal fixed expression. This is the only
3926 -- attribute whose functional description involves U_R.
3928 if Etype (E1) = Universal_Fixed then
3930 Conv : constant Node_Id := Make_Type_Conversion (Loc,
3931 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
3932 Expression => Relocate_Node (E1));
3940 Resolve (E1, Any_Real);
3946 when Attribute_Rounding =>
3947 Check_Floating_Point_Type_1;
3948 Set_Etype (N, P_Base_Type);
3949 Resolve (E1, P_Base_Type);
3955 when Attribute_Safe_Emax =>
3956 Check_Floating_Point_Type_0;
3957 Set_Etype (N, Universal_Integer);
3963 when Attribute_Safe_First =>
3964 Check_Floating_Point_Type_0;
3965 Set_Etype (N, Universal_Real);
3971 when Attribute_Safe_Large =>
3974 Set_Etype (N, Universal_Real);
3980 when Attribute_Safe_Last =>
3981 Check_Floating_Point_Type_0;
3982 Set_Etype (N, Universal_Real);
3988 when Attribute_Safe_Small =>
3991 Set_Etype (N, Universal_Real);
3997 when Attribute_Scale =>
3999 Check_Decimal_Fixed_Point_Type;
4000 Set_Etype (N, Universal_Integer);
4006 when Attribute_Scaling =>
4007 Check_Floating_Point_Type_2;
4008 Set_Etype (N, P_Base_Type);
4009 Resolve (E1, P_Base_Type);
4015 when Attribute_Signed_Zeros =>
4016 Check_Floating_Point_Type_0;
4017 Set_Etype (N, Standard_Boolean);
4023 when Attribute_Size | Attribute_VADS_Size => Size :
4027 -- If prefix is parameterless function call, rewrite and resolve
4030 if Is_Entity_Name (P)
4031 and then Ekind (Entity (P)) = E_Function
4035 -- Similar processing for a protected function call
4037 elsif Nkind (P) = N_Selected_Component
4038 and then Ekind (Entity (Selector_Name (P))) = E_Function
4043 if Is_Object_Reference (P) then
4044 Check_Object_Reference (P);
4046 elsif Is_Entity_Name (P)
4047 and then (Is_Type (Entity (P))
4048 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4052 elsif Nkind (P) = N_Type_Conversion
4053 and then not Comes_From_Source (P)
4058 Error_Attr_P ("invalid prefix for % attribute");
4061 Check_Not_Incomplete_Type;
4063 Set_Etype (N, Universal_Integer);
4070 when Attribute_Small =>
4073 Set_Etype (N, Universal_Real);
4079 when Attribute_Storage_Pool => Storage_Pool :
4083 if Is_Access_Type (P_Type) then
4084 if Ekind (P_Type) = E_Access_Subprogram_Type then
4086 ("cannot use % attribute for access-to-subprogram type");
4089 -- Set appropriate entity
4091 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4092 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4094 Set_Entity (N, RTE (RE_Global_Pool_Object));
4097 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4099 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4100 -- Storage_Pool since this attribute is not defined for such
4101 -- types (RM E.2.3(22)).
4103 Validate_Remote_Access_To_Class_Wide_Type (N);
4106 Error_Attr_P ("prefix of % attribute must be access type");
4114 when Attribute_Storage_Size => Storage_Size :
4118 if Is_Task_Type (P_Type) then
4119 Set_Etype (N, Universal_Integer);
4121 elsif Is_Access_Type (P_Type) then
4122 if Ekind (P_Type) = E_Access_Subprogram_Type then
4124 ("cannot use % attribute for access-to-subprogram type");
4127 if Is_Entity_Name (P)
4128 and then Is_Type (Entity (P))
4131 Set_Etype (N, Universal_Integer);
4133 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4134 -- Storage_Size since this attribute is not defined for
4135 -- such types (RM E.2.3(22)).
4137 Validate_Remote_Access_To_Class_Wide_Type (N);
4139 -- The prefix is allowed to be an implicit dereference
4140 -- of an access value designating a task.
4144 Set_Etype (N, Universal_Integer);
4148 Error_Attr_P ("prefix of % attribute must be access or task type");
4156 when Attribute_Storage_Unit =>
4157 Standard_Attribute (Ttypes.System_Storage_Unit);
4163 when Attribute_Stream_Size =>
4167 if Is_Entity_Name (P)
4168 and then Is_Elementary_Type (Entity (P))
4170 Set_Etype (N, Universal_Integer);
4172 Error_Attr_P ("invalid prefix for % attribute");
4179 when Attribute_Stub_Type =>
4183 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4185 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4188 ("prefix of% attribute must be remote access to classwide");
4195 when Attribute_Succ =>
4198 Resolve (E1, P_Base_Type);
4199 Set_Etype (N, P_Base_Type);
4201 -- Nothing to do for real type case
4203 if Is_Real_Type (P_Type) then
4206 -- If not modular type, test for overflow check required
4209 if not Is_Modular_Integer_Type (P_Type)
4210 and then not Range_Checks_Suppressed (P_Base_Type)
4212 Enable_Range_Check (E1);
4220 when Attribute_Tag => Tag :
4225 if not Is_Tagged_Type (P_Type) then
4226 Error_Attr_P ("prefix of % attribute must be tagged");
4228 -- Next test does not apply to generated code
4229 -- why not, and what does the illegal reference mean???
4231 elsif Is_Object_Reference (P)
4232 and then not Is_Class_Wide_Type (P_Type)
4233 and then Comes_From_Source (N)
4236 ("% attribute can only be applied to objects " &
4237 "of class - wide type");
4240 -- The prefix cannot be an incomplete type. However, references
4241 -- to 'Tag can be generated when expanding interface conversions,
4242 -- and this is legal.
4244 if Comes_From_Source (N) then
4245 Check_Not_Incomplete_Type;
4248 -- Set appropriate type
4250 Set_Etype (N, RTE (RE_Tag));
4257 when Attribute_Target_Name => Target_Name : declare
4258 TN : constant String := Sdefault.Target_Name.all;
4262 Check_Standard_Prefix;
4266 if TN (TL) = '/' or else TN (TL) = '\' then
4271 Make_String_Literal (Loc,
4272 Strval => TN (TN'First .. TL)));
4273 Analyze_And_Resolve (N, Standard_String);
4280 when Attribute_Terminated =>
4282 Set_Etype (N, Standard_Boolean);
4289 when Attribute_To_Address =>
4293 if Nkind (P) /= N_Identifier
4294 or else Chars (P) /= Name_System
4296 Error_Attr_P ("prefix of %attribute must be System");
4299 Generate_Reference (RTE (RE_Address), P);
4300 Analyze_And_Resolve (E1, Any_Integer);
4301 Set_Etype (N, RTE (RE_Address));
4307 when Attribute_To_Any =>
4309 Check_PolyORB_Attribute;
4310 Set_Etype (N, RTE (RE_Any));
4316 when Attribute_Truncation =>
4317 Check_Floating_Point_Type_1;
4318 Resolve (E1, P_Base_Type);
4319 Set_Etype (N, P_Base_Type);
4325 when Attribute_Type_Class =>
4328 Check_Not_Incomplete_Type;
4329 Set_Etype (N, RTE (RE_Type_Class));
4335 when Attribute_TypeCode =>
4337 Check_PolyORB_Attribute;
4338 Set_Etype (N, RTE (RE_TypeCode));
4344 when Attribute_UET_Address =>
4346 Check_Unit_Name (P);
4347 Set_Etype (N, RTE (RE_Address));
4349 -----------------------
4350 -- Unbiased_Rounding --
4351 -----------------------
4353 when Attribute_Unbiased_Rounding =>
4354 Check_Floating_Point_Type_1;
4355 Set_Etype (N, P_Base_Type);
4356 Resolve (E1, P_Base_Type);
4358 ----------------------
4359 -- Unchecked_Access --
4360 ----------------------
4362 when Attribute_Unchecked_Access =>
4363 if Comes_From_Source (N) then
4364 Check_Restriction (No_Unchecked_Access, N);
4367 Analyze_Access_Attribute;
4369 -------------------------
4370 -- Unconstrained_Array --
4371 -------------------------
4373 when Attribute_Unconstrained_Array =>
4376 Check_Not_Incomplete_Type;
4377 Set_Etype (N, Standard_Boolean);
4379 ------------------------------
4380 -- Universal_Literal_String --
4381 ------------------------------
4383 -- This is a GNAT specific attribute whose prefix must be a named
4384 -- number where the expression is either a single numeric literal,
4385 -- or a numeric literal immediately preceded by a minus sign. The
4386 -- result is equivalent to a string literal containing the text of
4387 -- the literal as it appeared in the source program with a possible
4388 -- leading minus sign.
4390 when Attribute_Universal_Literal_String => Universal_Literal_String :
4394 if not Is_Entity_Name (P)
4395 or else Ekind (Entity (P)) not in Named_Kind
4397 Error_Attr_P ("prefix for % attribute must be named number");
4404 Src : Source_Buffer_Ptr;
4407 Expr := Original_Node (Expression (Parent (Entity (P))));
4409 if Nkind (Expr) = N_Op_Minus then
4411 Expr := Original_Node (Right_Opnd (Expr));
4416 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4418 ("named number for % attribute must be simple literal", N);
4421 -- Build string literal corresponding to source literal text
4426 Store_String_Char (Get_Char_Code ('-'));
4430 Src := Source_Text (Get_Source_File_Index (S));
4432 while Src (S) /= ';' and then Src (S) /= ' ' loop
4433 Store_String_Char (Get_Char_Code (Src (S)));
4437 -- Now we rewrite the attribute with the string literal
4440 Make_String_Literal (Loc, End_String));
4444 end Universal_Literal_String;
4446 -------------------------
4447 -- Unrestricted_Access --
4448 -------------------------
4450 -- This is a GNAT specific attribute which is like Access except that
4451 -- all scope checks and checks for aliased views are omitted.
4453 when Attribute_Unrestricted_Access =>
4454 if Comes_From_Source (N) then
4455 Check_Restriction (No_Unchecked_Access, N);
4458 if Is_Entity_Name (P) then
4459 Set_Address_Taken (Entity (P));
4462 Analyze_Access_Attribute;
4468 when Attribute_Val => Val : declare
4471 Check_Discrete_Type;
4472 Resolve (E1, Any_Integer);
4473 Set_Etype (N, P_Base_Type);
4475 -- Note, we need a range check in general, but we wait for the
4476 -- Resolve call to do this, since we want to let Eval_Attribute
4477 -- have a chance to find an static illegality first!
4484 when Attribute_Valid =>
4487 -- Ignore check for object if we have a 'Valid reference generated
4488 -- by the expanded code, since in some cases valid checks can occur
4489 -- on items that are names, but are not objects (e.g. attributes).
4491 if Comes_From_Source (N) then
4492 Check_Object_Reference (P);
4495 if not Is_Scalar_Type (P_Type) then
4496 Error_Attr_P ("object for % attribute must be of scalar type");
4499 Set_Etype (N, Standard_Boolean);
4505 when Attribute_Value => Value :
4510 -- Case of enumeration type
4512 if Is_Enumeration_Type (P_Type) then
4513 Check_Restriction (No_Enumeration_Maps, N);
4515 -- Mark all enumeration literals as referenced, since the use of
4516 -- the Value attribute can implicitly reference any of the
4517 -- literals of the enumeration base type.
4520 Ent : Entity_Id := First_Literal (P_Base_Type);
4522 while Present (Ent) loop
4523 Set_Referenced (Ent);
4529 -- Set Etype before resolving expression because expansion of
4530 -- expression may require enclosing type. Note that the type
4531 -- returned by 'Value is the base type of the prefix type.
4533 Set_Etype (N, P_Base_Type);
4534 Validate_Non_Static_Attribute_Function_Call;
4541 when Attribute_Value_Size =>
4544 Check_Not_Incomplete_Type;
4545 Set_Etype (N, Universal_Integer);
4551 when Attribute_Version =>
4554 Set_Etype (N, RTE (RE_Version_String));
4560 when Attribute_Wchar_T_Size =>
4561 Standard_Attribute (Interfaces_Wchar_T_Size);
4567 when Attribute_Wide_Image => Wide_Image :
4570 Set_Etype (N, Standard_Wide_String);
4572 Resolve (E1, P_Base_Type);
4573 Validate_Non_Static_Attribute_Function_Call;
4576 ---------------------
4577 -- Wide_Wide_Image --
4578 ---------------------
4580 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
4583 Set_Etype (N, Standard_Wide_Wide_String);
4585 Resolve (E1, P_Base_Type);
4586 Validate_Non_Static_Attribute_Function_Call;
4587 end Wide_Wide_Image;
4593 when Attribute_Wide_Value => Wide_Value :
4598 -- Set Etype before resolving expression because expansion
4599 -- of expression may require enclosing type.
4601 Set_Etype (N, P_Type);
4602 Validate_Non_Static_Attribute_Function_Call;
4605 ---------------------
4606 -- Wide_Wide_Value --
4607 ---------------------
4609 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
4614 -- Set Etype before resolving expression because expansion
4615 -- of expression may require enclosing type.
4617 Set_Etype (N, P_Type);
4618 Validate_Non_Static_Attribute_Function_Call;
4619 end Wide_Wide_Value;
4621 ---------------------
4622 -- Wide_Wide_Width --
4623 ---------------------
4625 when Attribute_Wide_Wide_Width =>
4628 Set_Etype (N, Universal_Integer);
4634 when Attribute_Wide_Width =>
4637 Set_Etype (N, Universal_Integer);
4643 when Attribute_Width =>
4646 Set_Etype (N, Universal_Integer);
4652 when Attribute_Word_Size =>
4653 Standard_Attribute (System_Word_Size);
4659 when Attribute_Write =>
4661 Check_Stream_Attribute (TSS_Stream_Write);
4662 Set_Etype (N, Standard_Void_Type);
4663 Resolve (N, Standard_Void_Type);
4667 -- All errors raise Bad_Attribute, so that we get out before any further
4668 -- damage occurs when an error is detected (for example, if we check for
4669 -- one attribute expression, and the check succeeds, we want to be able
4670 -- to proceed securely assuming that an expression is in fact present.
4672 -- Note: we set the attribute analyzed in this case to prevent any
4673 -- attempt at reanalysis which could generate spurious error msgs.
4676 when Bad_Attribute =>
4678 Set_Etype (N, Any_Type);
4680 end Analyze_Attribute;
4682 --------------------
4683 -- Eval_Attribute --
4684 --------------------
4686 procedure Eval_Attribute (N : Node_Id) is
4687 Loc : constant Source_Ptr := Sloc (N);
4688 Aname : constant Name_Id := Attribute_Name (N);
4689 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
4690 P : constant Node_Id := Prefix (N);
4692 C_Type : constant Entity_Id := Etype (N);
4693 -- The type imposed by the context
4696 -- First expression, or Empty if none
4699 -- Second expression, or Empty if none
4701 P_Entity : Entity_Id;
4702 -- Entity denoted by prefix
4705 -- The type of the prefix
4707 P_Base_Type : Entity_Id;
4708 -- The base type of the prefix type
4710 P_Root_Type : Entity_Id;
4711 -- The root type of the prefix type
4714 -- True if the result is Static. This is set by the general processing
4715 -- to true if the prefix is static, and all expressions are static. It
4716 -- can be reset as processing continues for particular attributes
4718 Lo_Bound, Hi_Bound : Node_Id;
4719 -- Expressions for low and high bounds of type or array index referenced
4720 -- by First, Last, or Length attribute for array, set by Set_Bounds.
4723 -- Constraint error node used if we have an attribute reference has
4724 -- an argument that raises a constraint error. In this case we replace
4725 -- the attribute with a raise constraint_error node. This is important
4726 -- processing, since otherwise gigi might see an attribute which it is
4727 -- unprepared to deal with.
4729 function Aft_Value return Nat;
4730 -- Computes Aft value for current attribute prefix (used by Aft itself
4731 -- and also by Width for computing the Width of a fixed point type).
4733 procedure Check_Expressions;
4734 -- In case where the attribute is not foldable, the expressions, if
4735 -- any, of the attribute, are in a non-static context. This procedure
4736 -- performs the required additional checks.
4738 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
4739 -- Determines if the given type has compile time known bounds. Note
4740 -- that we enter the case statement even in cases where the prefix
4741 -- type does NOT have known bounds, so it is important to guard any
4742 -- attempt to evaluate both bounds with a call to this function.
4744 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
4745 -- This procedure is called when the attribute N has a non-static
4746 -- but compile time known value given by Val. It includes the
4747 -- necessary checks for out of range values.
4749 procedure Float_Attribute_Universal_Integer
4758 -- This procedure evaluates a float attribute with no arguments that
4759 -- returns a universal integer result. The parameters give the values
4760 -- for the possible floating-point root types. See ttypef for details.
4761 -- The prefix type is a float type (and is thus not a generic type).
4763 procedure Float_Attribute_Universal_Real
4764 (IEEES_Val : String;
4771 AAMPL_Val : String);
4772 -- This procedure evaluates a float attribute with no arguments that
4773 -- returns a universal real result. The parameters give the values
4774 -- required for the possible floating-point root types in string
4775 -- format as real literals with a possible leading minus sign.
4776 -- The prefix type is a float type (and is thus not a generic type).
4778 function Fore_Value return Nat;
4779 -- Computes the Fore value for the current attribute prefix, which is
4780 -- known to be a static fixed-point type. Used by Fore and Width.
4782 function Mantissa return Uint;
4783 -- Returns the Mantissa value for the prefix type
4785 procedure Set_Bounds;
4786 -- Used for First, Last and Length attributes applied to an array or
4787 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
4788 -- and high bound expressions for the index referenced by the attribute
4789 -- designator (i.e. the first index if no expression is present, and
4790 -- the N'th index if the value N is present as an expression). Also
4791 -- used for First and Last of scalar types. Static is reset to False
4792 -- if the type or index type is not statically constrained.
4794 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
4795 -- Verify that the prefix of a potentially static array attribute
4796 -- satisfies the conditions of 4.9 (14).
4802 function Aft_Value return Nat is
4808 Delta_Val := Delta_Value (P_Type);
4809 while Delta_Val < Ureal_Tenth loop
4810 Delta_Val := Delta_Val * Ureal_10;
4811 Result := Result + 1;
4817 -----------------------
4818 -- Check_Expressions --
4819 -----------------------
4821 procedure Check_Expressions is
4825 while Present (E) loop
4826 Check_Non_Static_Context (E);
4829 end Check_Expressions;
4831 ----------------------------------
4832 -- Compile_Time_Known_Attribute --
4833 ----------------------------------
4835 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
4836 T : constant Entity_Id := Etype (N);
4839 Fold_Uint (N, Val, False);
4841 -- Check that result is in bounds of the type if it is static
4843 if Is_In_Range (N, T) then
4846 elsif Is_Out_Of_Range (N, T) then
4847 Apply_Compile_Time_Constraint_Error
4848 (N, "value not in range of}?", CE_Range_Check_Failed);
4850 elsif not Range_Checks_Suppressed (T) then
4851 Enable_Range_Check (N);
4854 Set_Do_Range_Check (N, False);
4856 end Compile_Time_Known_Attribute;
4858 -------------------------------
4859 -- Compile_Time_Known_Bounds --
4860 -------------------------------
4862 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
4865 Compile_Time_Known_Value (Type_Low_Bound (Typ))
4867 Compile_Time_Known_Value (Type_High_Bound (Typ));
4868 end Compile_Time_Known_Bounds;
4870 ---------------------------------------
4871 -- Float_Attribute_Universal_Integer --
4872 ---------------------------------------
4874 procedure Float_Attribute_Universal_Integer
4885 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4888 if Vax_Float (P_Base_Type) then
4889 if Digs = VAXFF_Digits then
4891 elsif Digs = VAXDF_Digits then
4893 else pragma Assert (Digs = VAXGF_Digits);
4897 elsif Is_AAMP_Float (P_Base_Type) then
4898 if Digs = AAMPS_Digits then
4900 else pragma Assert (Digs = AAMPL_Digits);
4905 if Digs = IEEES_Digits then
4907 elsif Digs = IEEEL_Digits then
4909 else pragma Assert (Digs = IEEEX_Digits);
4914 Fold_Uint (N, UI_From_Int (Val), True);
4915 end Float_Attribute_Universal_Integer;
4917 ------------------------------------
4918 -- Float_Attribute_Universal_Real --
4919 ------------------------------------
4921 procedure Float_Attribute_Universal_Real
4922 (IEEES_Val : String;
4932 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4935 if Vax_Float (P_Base_Type) then
4936 if Digs = VAXFF_Digits then
4937 Val := Real_Convert (VAXFF_Val);
4938 elsif Digs = VAXDF_Digits then
4939 Val := Real_Convert (VAXDF_Val);
4940 else pragma Assert (Digs = VAXGF_Digits);
4941 Val := Real_Convert (VAXGF_Val);
4944 elsif Is_AAMP_Float (P_Base_Type) then
4945 if Digs = AAMPS_Digits then
4946 Val := Real_Convert (AAMPS_Val);
4947 else pragma Assert (Digs = AAMPL_Digits);
4948 Val := Real_Convert (AAMPL_Val);
4952 if Digs = IEEES_Digits then
4953 Val := Real_Convert (IEEES_Val);
4954 elsif Digs = IEEEL_Digits then
4955 Val := Real_Convert (IEEEL_Val);
4956 else pragma Assert (Digs = IEEEX_Digits);
4957 Val := Real_Convert (IEEEX_Val);
4961 Set_Sloc (Val, Loc);
4963 Set_Is_Static_Expression (N, Static);
4964 Analyze_And_Resolve (N, C_Type);
4965 end Float_Attribute_Universal_Real;
4971 -- Note that the Fore calculation is based on the actual values
4972 -- of the bounds, and does not take into account possible rounding.
4974 function Fore_Value return Nat is
4975 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
4976 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
4977 Small : constant Ureal := Small_Value (P_Type);
4978 Lo_Real : constant Ureal := Lo * Small;
4979 Hi_Real : constant Ureal := Hi * Small;
4984 -- Bounds are given in terms of small units, so first compute
4985 -- proper values as reals.
4987 T := UR_Max (abs Lo_Real, abs Hi_Real);
4990 -- Loop to compute proper value if more than one digit required
4992 while T >= Ureal_10 loop
5004 -- Table of mantissa values accessed by function Computed using
5007 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5009 -- where D is T'Digits (RM83 3.5.7)
5011 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5053 function Mantissa return Uint is
5056 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5063 procedure Set_Bounds is
5069 -- For a string literal subtype, we have to construct the bounds.
5070 -- Valid Ada code never applies attributes to string literals, but
5071 -- it is convenient to allow the expander to generate attribute
5072 -- references of this type (e.g. First and Last applied to a string
5075 -- Note that the whole point of the E_String_Literal_Subtype is to
5076 -- avoid this construction of bounds, but the cases in which we
5077 -- have to materialize them are rare enough that we don't worry!
5079 -- The low bound is simply the low bound of the base type. The
5080 -- high bound is computed from the length of the string and this
5083 if Ekind (P_Type) = E_String_Literal_Subtype then
5084 Ityp := Etype (First_Index (Base_Type (P_Type)));
5085 Lo_Bound := Type_Low_Bound (Ityp);
5088 Make_Integer_Literal (Sloc (P),
5090 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5092 Set_Parent (Hi_Bound, P);
5093 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5096 -- For non-array case, just get bounds of scalar type
5098 elsif Is_Scalar_Type (P_Type) then
5101 -- For a fixed-point type, we must freeze to get the attributes
5102 -- of the fixed-point type set now so we can reference them.
5104 if Is_Fixed_Point_Type (P_Type)
5105 and then not Is_Frozen (Base_Type (P_Type))
5106 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5107 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5109 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5112 -- For array case, get type of proper index
5118 Ndim := UI_To_Int (Expr_Value (E1));
5121 Indx := First_Index (P_Type);
5122 for J in 1 .. Ndim - 1 loop
5126 -- If no index type, get out (some other error occurred, and
5127 -- we don't have enough information to complete the job!)
5135 Ityp := Etype (Indx);
5138 -- A discrete range in an index constraint is allowed to be a
5139 -- subtype indication. This is syntactically a pain, but should
5140 -- not propagate to the entity for the corresponding index subtype.
5141 -- After checking that the subtype indication is legal, the range
5142 -- of the subtype indication should be transfered to the entity.
5143 -- The attributes for the bounds should remain the simple retrievals
5144 -- that they are now.
5146 Lo_Bound := Type_Low_Bound (Ityp);
5147 Hi_Bound := Type_High_Bound (Ityp);
5149 if not Is_Static_Subtype (Ityp) then
5154 -------------------------------
5155 -- Statically_Denotes_Entity --
5156 -------------------------------
5158 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5162 if not Is_Entity_Name (N) then
5169 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5170 or else Statically_Denotes_Entity (Renamed_Object (E));
5171 end Statically_Denotes_Entity;
5173 -- Start of processing for Eval_Attribute
5176 -- Acquire first two expressions (at the moment, no attributes
5177 -- take more than two expressions in any case).
5179 if Present (Expressions (N)) then
5180 E1 := First (Expressions (N));
5187 -- Special processing for Enabled attribute. This attribute has a very
5188 -- special prefix, and the easiest way to avoid lots of special checks
5189 -- to protect this special prefix from causing trouble is to deal with
5190 -- this attribute immediately and be done with it.
5192 if Id = Attribute_Enabled then
5194 -- Evaluate the Enabled attribute
5196 -- We skip evaluation if the expander is not active. This is not just
5197 -- an optimization. It is of key importance that we not rewrite the
5198 -- attribute in a generic template, since we want to pick up the
5199 -- setting of the check in the instance, and testing expander active
5200 -- is as easy way of doing this as any.
5202 if Expander_Active then
5204 C : constant Check_Id := Get_Check_Id (Chars (P));
5209 if C in Predefined_Check_Id then
5210 R := Scope_Suppress (C);
5212 R := Is_Check_Suppressed (Empty, C);
5216 R := Is_Check_Suppressed (Entity (E1), C);
5220 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5222 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5230 -- Special processing for cases where the prefix is an object. For
5231 -- this purpose, a string literal counts as an object (attributes
5232 -- of string literals can only appear in generated code).
5234 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5236 -- For Component_Size, the prefix is an array object, and we apply
5237 -- the attribute to the type of the object. This is allowed for
5238 -- both unconstrained and constrained arrays, since the bounds
5239 -- have no influence on the value of this attribute.
5241 if Id = Attribute_Component_Size then
5242 P_Entity := Etype (P);
5244 -- For First and Last, the prefix is an array object, and we apply
5245 -- the attribute to the type of the array, but we need a constrained
5246 -- type for this, so we use the actual subtype if available.
5248 elsif Id = Attribute_First
5252 Id = Attribute_Length
5255 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5258 if Present (AS) and then Is_Constrained (AS) then
5261 -- If we have an unconstrained type, cannot fold
5269 -- For Size, give size of object if available, otherwise we
5270 -- cannot fold Size.
5272 elsif Id = Attribute_Size then
5273 if Is_Entity_Name (P)
5274 and then Known_Esize (Entity (P))
5276 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5284 -- For Alignment, give size of object if available, otherwise we
5285 -- cannot fold Alignment.
5287 elsif Id = Attribute_Alignment then
5288 if Is_Entity_Name (P)
5289 and then Known_Alignment (Entity (P))
5291 Fold_Uint (N, Alignment (Entity (P)), False);
5299 -- No other attributes for objects are folded
5306 -- Cases where P is not an object. Cannot do anything if P is
5307 -- not the name of an entity.
5309 elsif not Is_Entity_Name (P) then
5313 -- Otherwise get prefix entity
5316 P_Entity := Entity (P);
5319 -- At this stage P_Entity is the entity to which the attribute
5320 -- is to be applied. This is usually simply the entity of the
5321 -- prefix, except in some cases of attributes for objects, where
5322 -- as described above, we apply the attribute to the object type.
5324 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5325 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5326 -- Note we allow non-static non-generic types at this stage as further
5329 if Is_Type (P_Entity)
5330 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5331 and then (not Is_Generic_Type (P_Entity))
5335 -- Second foldable possibility is an array object (RM 4.9(8))
5337 elsif (Ekind (P_Entity) = E_Variable
5339 Ekind (P_Entity) = E_Constant)
5340 and then Is_Array_Type (Etype (P_Entity))
5341 and then (not Is_Generic_Type (Etype (P_Entity)))
5343 P_Type := Etype (P_Entity);
5345 -- If the entity is an array constant with an unconstrained nominal
5346 -- subtype then get the type from the initial value. If the value has
5347 -- been expanded into assignments, there is no expression and the
5348 -- attribute reference remains dynamic.
5350 -- We could do better here and retrieve the type ???
5352 if Ekind (P_Entity) = E_Constant
5353 and then not Is_Constrained (P_Type)
5355 if No (Constant_Value (P_Entity)) then
5358 P_Type := Etype (Constant_Value (P_Entity));
5362 -- Definite must be folded if the prefix is not a generic type,
5363 -- that is to say if we are within an instantiation. Same processing
5364 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5365 -- Has_Tagged_Value, and Unconstrained_Array.
5367 elsif (Id = Attribute_Definite
5369 Id = Attribute_Has_Access_Values
5371 Id = Attribute_Has_Discriminants
5373 Id = Attribute_Has_Tagged_Values
5375 Id = Attribute_Type_Class
5377 Id = Attribute_Unconstrained_Array)
5378 and then not Is_Generic_Type (P_Entity)
5382 -- We can fold 'Size applied to a type if the size is known (as happens
5383 -- for a size from an attribute definition clause). At this stage, this
5384 -- can happen only for types (e.g. record types) for which the size is
5385 -- always non-static. We exclude generic types from consideration (since
5386 -- they have bogus sizes set within templates).
5388 elsif Id = Attribute_Size
5389 and then Is_Type (P_Entity)
5390 and then (not Is_Generic_Type (P_Entity))
5391 and then Known_Static_RM_Size (P_Entity)
5393 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5396 -- We can fold 'Alignment applied to a type if the alignment is known
5397 -- (as happens for an alignment from an attribute definition clause).
5398 -- At this stage, this can happen only for types (e.g. record
5399 -- types) for which the size is always non-static. We exclude
5400 -- generic types from consideration (since they have bogus
5401 -- sizes set within templates).
5403 elsif Id = Attribute_Alignment
5404 and then Is_Type (P_Entity)
5405 and then (not Is_Generic_Type (P_Entity))
5406 and then Known_Alignment (P_Entity)
5408 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5411 -- If this is an access attribute that is known to fail accessibility
5412 -- check, rewrite accordingly.
5414 elsif Attribute_Name (N) = Name_Access
5415 and then Raises_Constraint_Error (N)
5418 Make_Raise_Program_Error (Loc,
5419 Reason => PE_Accessibility_Check_Failed));
5420 Set_Etype (N, C_Type);
5423 -- No other cases are foldable (they certainly aren't static, and at
5424 -- the moment we don't try to fold any cases other than these three).
5431 -- If either attribute or the prefix is Any_Type, then propagate
5432 -- Any_Type to the result and don't do anything else at all.
5434 if P_Type = Any_Type
5435 or else (Present (E1) and then Etype (E1) = Any_Type)
5436 or else (Present (E2) and then Etype (E2) = Any_Type)
5438 Set_Etype (N, Any_Type);
5442 -- Scalar subtype case. We have not yet enforced the static requirement
5443 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5444 -- of non-static attribute references (e.g. S'Digits for a non-static
5445 -- floating-point type, which we can compute at compile time).
5447 -- Note: this folding of non-static attributes is not simply a case of
5448 -- optimization. For many of the attributes affected, Gigi cannot handle
5449 -- the attribute and depends on the front end having folded them away.
5451 -- Note: although we don't require staticness at this stage, we do set
5452 -- the Static variable to record the staticness, for easy reference by
5453 -- those attributes where it matters (e.g. Succ and Pred), and also to
5454 -- be used to ensure that non-static folded things are not marked as
5455 -- being static (a check that is done right at the end).
5457 P_Root_Type := Root_Type (P_Type);
5458 P_Base_Type := Base_Type (P_Type);
5460 -- If the root type or base type is generic, then we cannot fold. This
5461 -- test is needed because subtypes of generic types are not always
5462 -- marked as being generic themselves (which seems odd???)
5464 if Is_Generic_Type (P_Root_Type)
5465 or else Is_Generic_Type (P_Base_Type)
5470 if Is_Scalar_Type (P_Type) then
5471 Static := Is_OK_Static_Subtype (P_Type);
5473 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5474 -- since we can't do anything with unconstrained arrays. In addition,
5475 -- only the First, Last and Length attributes are possibly static.
5477 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5478 -- Type_Class, and Unconstrained_Array are again exceptions, because
5479 -- they apply as well to unconstrained types.
5481 -- In addition Component_Size is an exception since it is possibly
5482 -- foldable, even though it is never static, and it does apply to
5483 -- unconstrained arrays. Furthermore, it is essential to fold this
5484 -- in the packed case, since otherwise the value will be incorrect.
5486 elsif Id = Attribute_Definite
5488 Id = Attribute_Has_Access_Values
5490 Id = Attribute_Has_Discriminants
5492 Id = Attribute_Has_Tagged_Values
5494 Id = Attribute_Type_Class
5496 Id = Attribute_Unconstrained_Array
5498 Id = Attribute_Component_Size
5503 if not Is_Constrained (P_Type)
5504 or else (Id /= Attribute_First and then
5505 Id /= Attribute_Last and then
5506 Id /= Attribute_Length)
5512 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5513 -- scalar case, we hold off on enforcing staticness, since there are
5514 -- cases which we can fold at compile time even though they are not
5515 -- static (e.g. 'Length applied to a static index, even though other
5516 -- non-static indexes make the array type non-static). This is only
5517 -- an optimization, but it falls out essentially free, so why not.
5518 -- Again we compute the variable Static for easy reference later
5519 -- (note that no array attributes are static in Ada 83).
5521 Static := Ada_Version >= Ada_95
5522 and then Statically_Denotes_Entity (P);
5528 N := First_Index (P_Type);
5529 while Present (N) loop
5530 Static := Static and then Is_Static_Subtype (Etype (N));
5532 -- If however the index type is generic, attributes cannot
5535 if Is_Generic_Type (Etype (N))
5536 and then Id /= Attribute_Component_Size
5546 -- Check any expressions that are present. Note that these expressions,
5547 -- depending on the particular attribute type, are either part of the
5548 -- attribute designator, or they are arguments in a case where the
5549 -- attribute reference returns a function. In the latter case, the
5550 -- rule in (RM 4.9(22)) applies and in particular requires the type
5551 -- of the expressions to be scalar in order for the attribute to be
5552 -- considered to be static.
5559 while Present (E) loop
5561 -- If expression is not static, then the attribute reference
5562 -- result certainly cannot be static.
5564 if not Is_Static_Expression (E) then
5568 -- If the result is not known at compile time, or is not of
5569 -- a scalar type, then the result is definitely not static,
5570 -- so we can quit now.
5572 if not Compile_Time_Known_Value (E)
5573 or else not Is_Scalar_Type (Etype (E))
5575 -- An odd special case, if this is a Pos attribute, this
5576 -- is where we need to apply a range check since it does
5577 -- not get done anywhere else.
5579 if Id = Attribute_Pos then
5580 if Is_Integer_Type (Etype (E)) then
5581 Apply_Range_Check (E, Etype (N));
5588 -- If the expression raises a constraint error, then so does
5589 -- the attribute reference. We keep going in this case because
5590 -- we are still interested in whether the attribute reference
5591 -- is static even if it is not static.
5593 elsif Raises_Constraint_Error (E) then
5594 Set_Raises_Constraint_Error (N);
5600 if Raises_Constraint_Error (Prefix (N)) then
5605 -- Deal with the case of a static attribute reference that raises
5606 -- constraint error. The Raises_Constraint_Error flag will already
5607 -- have been set, and the Static flag shows whether the attribute
5608 -- reference is static. In any case we certainly can't fold such an
5609 -- attribute reference.
5611 -- Note that the rewriting of the attribute node with the constraint
5612 -- error node is essential in this case, because otherwise Gigi might
5613 -- blow up on one of the attributes it never expects to see.
5615 -- The constraint_error node must have the type imposed by the context,
5616 -- to avoid spurious errors in the enclosing expression.
5618 if Raises_Constraint_Error (N) then
5620 Make_Raise_Constraint_Error (Sloc (N),
5621 Reason => CE_Range_Check_Failed);
5622 Set_Etype (CE_Node, Etype (N));
5623 Set_Raises_Constraint_Error (CE_Node);
5625 Rewrite (N, Relocate_Node (CE_Node));
5626 Set_Is_Static_Expression (N, Static);
5630 -- At this point we have a potentially foldable attribute reference.
5631 -- If Static is set, then the attribute reference definitely obeys
5632 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
5633 -- folded. If Static is not set, then the attribute may or may not
5634 -- be foldable, and the individual attribute processing routines
5635 -- test Static as required in cases where it makes a difference.
5637 -- In the case where Static is not set, we do know that all the
5638 -- expressions present are at least known at compile time (we
5639 -- assumed above that if this was not the case, then there was
5640 -- no hope of static evaluation). However, we did not require
5641 -- that the bounds of the prefix type be compile time known,
5642 -- let alone static). That's because there are many attributes
5643 -- that can be computed at compile time on non-static subtypes,
5644 -- even though such references are not static expressions.
5652 when Attribute_Adjacent =>
5655 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5661 when Attribute_Aft =>
5662 Fold_Uint (N, UI_From_Int (Aft_Value), True);
5668 when Attribute_Alignment => Alignment_Block : declare
5669 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5672 -- Fold if alignment is set and not otherwise
5674 if Known_Alignment (P_TypeA) then
5675 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
5677 end Alignment_Block;
5683 -- Can only be folded in No_Ast_Handler case
5685 when Attribute_AST_Entry =>
5686 if not Is_AST_Entry (P_Entity) then
5688 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
5697 -- Bit can never be folded
5699 when Attribute_Bit =>
5706 -- Body_version can never be static
5708 when Attribute_Body_Version =>
5715 when Attribute_Ceiling =>
5717 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
5719 --------------------
5720 -- Component_Size --
5721 --------------------
5723 when Attribute_Component_Size =>
5724 if Known_Static_Component_Size (P_Type) then
5725 Fold_Uint (N, Component_Size (P_Type), False);
5732 when Attribute_Compose =>
5735 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
5742 -- Constrained is never folded for now, there may be cases that
5743 -- could be handled at compile time. To be looked at later.
5745 when Attribute_Constrained =>
5752 when Attribute_Copy_Sign =>
5755 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5761 when Attribute_Delta =>
5762 Fold_Ureal (N, Delta_Value (P_Type), True);
5768 when Attribute_Definite =>
5769 Rewrite (N, New_Occurrence_Of (
5770 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
5771 Analyze_And_Resolve (N, Standard_Boolean);
5777 when Attribute_Denorm =>
5779 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
5785 when Attribute_Digits =>
5786 Fold_Uint (N, Digits_Value (P_Type), True);
5792 when Attribute_Emax =>
5794 -- Ada 83 attribute is defined as (RM83 3.5.8)
5796 -- T'Emax = 4 * T'Mantissa
5798 Fold_Uint (N, 4 * Mantissa, True);
5804 when Attribute_Enum_Rep =>
5806 -- For an enumeration type with a non-standard representation use
5807 -- the Enumeration_Rep field of the proper constant. Note that this
5808 -- will not work for types Character/Wide_[Wide-]Character, since no
5809 -- real entities are created for the enumeration literals, but that
5810 -- does not matter since these two types do not have non-standard
5811 -- representations anyway.
5813 if Is_Enumeration_Type (P_Type)
5814 and then Has_Non_Standard_Rep (P_Type)
5816 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
5818 -- For enumeration types with standard representations and all
5819 -- other cases (i.e. all integer and modular types), Enum_Rep
5820 -- is equivalent to Pos.
5823 Fold_Uint (N, Expr_Value (E1), Static);
5830 when Attribute_Enum_Val => Enum_Val : declare
5834 -- We have something like Enum_Type'Enum_Val (23), so search for a
5835 -- corresponding value in the list of Enum_Rep values for the type.
5837 Lit := First_Literal (P_Base_Type);
5839 if Enumeration_Rep (Lit) = Expr_Value (E1) then
5840 Fold_Uint (N, Enumeration_Pos (Lit), Static);
5847 Apply_Compile_Time_Constraint_Error
5848 (N, "no representation value matches",
5849 CE_Range_Check_Failed,
5850 Warn => not Static);
5860 when Attribute_Epsilon =>
5862 -- Ada 83 attribute is defined as (RM83 3.5.8)
5864 -- T'Epsilon = 2.0**(1 - T'Mantissa)
5866 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
5872 when Attribute_Exponent =>
5874 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
5880 when Attribute_First => First_Attr :
5884 if Compile_Time_Known_Value (Lo_Bound) then
5885 if Is_Real_Type (P_Type) then
5886 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
5888 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
5897 when Attribute_Fixed_Value =>
5904 when Attribute_Floor =>
5906 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
5912 when Attribute_Fore =>
5913 if Compile_Time_Known_Bounds (P_Type) then
5914 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
5921 when Attribute_Fraction =>
5923 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
5925 -----------------------
5926 -- Has_Access_Values --
5927 -----------------------
5929 when Attribute_Has_Access_Values =>
5930 Rewrite (N, New_Occurrence_Of
5931 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
5932 Analyze_And_Resolve (N, Standard_Boolean);
5934 -----------------------
5935 -- Has_Discriminants --
5936 -----------------------
5938 when Attribute_Has_Discriminants =>
5939 Rewrite (N, New_Occurrence_Of (
5940 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
5941 Analyze_And_Resolve (N, Standard_Boolean);
5943 -----------------------
5944 -- Has_Tagged_Values --
5945 -----------------------
5947 when Attribute_Has_Tagged_Values =>
5948 Rewrite (N, New_Occurrence_Of
5949 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
5950 Analyze_And_Resolve (N, Standard_Boolean);
5956 when Attribute_Identity =>
5963 -- Image is a scalar attribute, but is never static, because it is
5964 -- not a static function (having a non-scalar argument (RM 4.9(22))
5965 -- However, we can constant-fold the image of an enumeration literal
5966 -- if names are available.
5968 when Attribute_Image =>
5969 if Is_Entity_Name (E1)
5970 and then Ekind (Entity (E1)) = E_Enumeration_Literal
5971 and then not Discard_Names (First_Subtype (Etype (E1)))
5972 and then not Global_Discard_Names
5975 Lit : constant Entity_Id := Entity (E1);
5979 Get_Unqualified_Decoded_Name_String (Chars (Lit));
5980 Set_Casing (All_Upper_Case);
5981 Store_String_Chars (Name_Buffer (1 .. Name_Len));
5983 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
5984 Analyze_And_Resolve (N, Standard_String);
5985 Set_Is_Static_Expression (N, False);
5993 -- Img is a scalar attribute, but is never static, because it is
5994 -- not a static function (having a non-scalar argument (RM 4.9(22))
5996 when Attribute_Img =>
6003 -- We never try to fold Integer_Value (though perhaps we could???)
6005 when Attribute_Integer_Value =>
6012 -- Invalid_Value is a scalar attribute that is never static, because
6013 -- the value is by design out of range.
6015 when Attribute_Invalid_Value =>
6022 when Attribute_Large =>
6024 -- For fixed-point, we use the identity:
6026 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6028 if Is_Fixed_Point_Type (P_Type) then
6030 Make_Op_Multiply (Loc,
6032 Make_Op_Subtract (Loc,
6036 Make_Real_Literal (Loc, Ureal_2),
6038 Make_Attribute_Reference (Loc,
6040 Attribute_Name => Name_Mantissa)),
6041 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6044 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6046 Analyze_And_Resolve (N, C_Type);
6048 -- Floating-point (Ada 83 compatibility)
6051 -- Ada 83 attribute is defined as (RM83 3.5.8)
6053 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6057 -- T'Emax = 4 * T'Mantissa
6060 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6068 when Attribute_Last => Last :
6072 if Compile_Time_Known_Value (Hi_Bound) then
6073 if Is_Real_Type (P_Type) then
6074 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6076 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6085 when Attribute_Leading_Part =>
6087 Eval_Fat.Leading_Part
6088 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6094 when Attribute_Length => Length : declare
6098 -- In the case of a generic index type, the bounds may
6099 -- appear static but the computation is not meaningful,
6100 -- and may generate a spurious warning.
6102 Ind := First_Index (P_Type);
6104 while Present (Ind) loop
6105 if Is_Generic_Type (Etype (Ind)) then
6114 if Compile_Time_Known_Value (Lo_Bound)
6115 and then Compile_Time_Known_Value (Hi_Bound)
6118 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6127 when Attribute_Machine =>
6130 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6137 when Attribute_Machine_Emax =>
6138 Float_Attribute_Universal_Integer (
6146 AAMPL_Machine_Emax);
6152 when Attribute_Machine_Emin =>
6153 Float_Attribute_Universal_Integer (
6161 AAMPL_Machine_Emin);
6163 ----------------------
6164 -- Machine_Mantissa --
6165 ----------------------
6167 when Attribute_Machine_Mantissa =>
6168 Float_Attribute_Universal_Integer (
6169 IEEES_Machine_Mantissa,
6170 IEEEL_Machine_Mantissa,
6171 IEEEX_Machine_Mantissa,
6172 VAXFF_Machine_Mantissa,
6173 VAXDF_Machine_Mantissa,
6174 VAXGF_Machine_Mantissa,
6175 AAMPS_Machine_Mantissa,
6176 AAMPL_Machine_Mantissa);
6178 -----------------------
6179 -- Machine_Overflows --
6180 -----------------------
6182 when Attribute_Machine_Overflows =>
6184 -- Always true for fixed-point
6186 if Is_Fixed_Point_Type (P_Type) then
6187 Fold_Uint (N, True_Value, True);
6189 -- Floating point case
6193 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6201 when Attribute_Machine_Radix =>
6202 if Is_Fixed_Point_Type (P_Type) then
6203 if Is_Decimal_Fixed_Point_Type (P_Type)
6204 and then Machine_Radix_10 (P_Type)
6206 Fold_Uint (N, Uint_10, True);
6208 Fold_Uint (N, Uint_2, True);
6211 -- All floating-point type always have radix 2
6214 Fold_Uint (N, Uint_2, True);
6217 ----------------------
6218 -- Machine_Rounding --
6219 ----------------------
6221 -- Note: for the folding case, it is fine to treat Machine_Rounding
6222 -- exactly the same way as Rounding, since this is one of the allowed
6223 -- behaviors, and performance is not an issue here. It might be a bit
6224 -- better to give the same result as it would give at run-time, even
6225 -- though the non-determinism is certainly permitted.
6227 when Attribute_Machine_Rounding =>
6229 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6231 --------------------
6232 -- Machine_Rounds --
6233 --------------------
6235 when Attribute_Machine_Rounds =>
6237 -- Always False for fixed-point
6239 if Is_Fixed_Point_Type (P_Type) then
6240 Fold_Uint (N, False_Value, True);
6242 -- Else yield proper floating-point result
6246 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6253 -- Note: Machine_Size is identical to Object_Size
6255 when Attribute_Machine_Size => Machine_Size : declare
6256 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6259 if Known_Esize (P_TypeA) then
6260 Fold_Uint (N, Esize (P_TypeA), True);
6268 when Attribute_Mantissa =>
6270 -- Fixed-point mantissa
6272 if Is_Fixed_Point_Type (P_Type) then
6274 -- Compile time foldable case
6276 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6278 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6280 -- The calculation of the obsolete Ada 83 attribute Mantissa
6281 -- is annoying, because of AI00143, quoted here:
6283 -- !question 84-01-10
6285 -- Consider the model numbers for F:
6287 -- type F is delta 1.0 range -7.0 .. 8.0;
6289 -- The wording requires that F'MANTISSA be the SMALLEST
6290 -- integer number for which each bound of the specified
6291 -- range is either a model number or lies at most small
6292 -- distant from a model number. This means F'MANTISSA
6293 -- is required to be 3 since the range -7.0 .. 7.0 fits
6294 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6295 -- number, namely, 7. Is this analysis correct? Note that
6296 -- this implies the upper bound of the range is not
6297 -- represented as a model number.
6299 -- !response 84-03-17
6301 -- The analysis is correct. The upper and lower bounds for
6302 -- a fixed point type can lie outside the range of model
6313 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6314 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6315 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6316 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6318 -- If the Bound is exactly a model number, i.e. a multiple
6319 -- of Small, then we back it off by one to get the integer
6320 -- value that must be representable.
6322 if Small_Value (P_Type) * Max_Man = Bound then
6323 Max_Man := Max_Man - 1;
6326 -- Now find corresponding size = Mantissa value
6329 while 2 ** Siz < Max_Man loop
6333 Fold_Uint (N, Siz, True);
6337 -- The case of dynamic bounds cannot be evaluated at compile
6338 -- time. Instead we use a runtime routine (see Exp_Attr).
6343 -- Floating-point Mantissa
6346 Fold_Uint (N, Mantissa, True);
6353 when Attribute_Max => Max :
6355 if Is_Real_Type (P_Type) then
6357 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6359 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6363 ----------------------------------
6364 -- Max_Size_In_Storage_Elements --
6365 ----------------------------------
6367 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6368 -- Storage_Unit boundary. We can fold any cases for which the size
6369 -- is known by the front end.
6371 when Attribute_Max_Size_In_Storage_Elements =>
6372 if Known_Esize (P_Type) then
6374 (Esize (P_Type) + System_Storage_Unit - 1) /
6375 System_Storage_Unit,
6379 --------------------
6380 -- Mechanism_Code --
6381 --------------------
6383 when Attribute_Mechanism_Code =>
6387 Mech : Mechanism_Type;
6391 Mech := Mechanism (P_Entity);
6394 Val := UI_To_Int (Expr_Value (E1));
6396 Formal := First_Formal (P_Entity);
6397 for J in 1 .. Val - 1 loop
6398 Next_Formal (Formal);
6400 Mech := Mechanism (Formal);
6404 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6412 when Attribute_Min => Min :
6414 if Is_Real_Type (P_Type) then
6416 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6419 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6427 when Attribute_Mod =>
6429 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6435 when Attribute_Model =>
6437 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
6443 when Attribute_Model_Emin =>
6444 Float_Attribute_Universal_Integer (
6458 when Attribute_Model_Epsilon =>
6459 Float_Attribute_Universal_Real (
6460 IEEES_Model_Epsilon'Universal_Literal_String,
6461 IEEEL_Model_Epsilon'Universal_Literal_String,
6462 IEEEX_Model_Epsilon'Universal_Literal_String,
6463 VAXFF_Model_Epsilon'Universal_Literal_String,
6464 VAXDF_Model_Epsilon'Universal_Literal_String,
6465 VAXGF_Model_Epsilon'Universal_Literal_String,
6466 AAMPS_Model_Epsilon'Universal_Literal_String,
6467 AAMPL_Model_Epsilon'Universal_Literal_String);
6469 --------------------
6470 -- Model_Mantissa --
6471 --------------------
6473 when Attribute_Model_Mantissa =>
6474 Float_Attribute_Universal_Integer (
6475 IEEES_Model_Mantissa,
6476 IEEEL_Model_Mantissa,
6477 IEEEX_Model_Mantissa,
6478 VAXFF_Model_Mantissa,
6479 VAXDF_Model_Mantissa,
6480 VAXGF_Model_Mantissa,
6481 AAMPS_Model_Mantissa,
6482 AAMPL_Model_Mantissa);
6488 when Attribute_Model_Small =>
6489 Float_Attribute_Universal_Real (
6490 IEEES_Model_Small'Universal_Literal_String,
6491 IEEEL_Model_Small'Universal_Literal_String,
6492 IEEEX_Model_Small'Universal_Literal_String,
6493 VAXFF_Model_Small'Universal_Literal_String,
6494 VAXDF_Model_Small'Universal_Literal_String,
6495 VAXGF_Model_Small'Universal_Literal_String,
6496 AAMPS_Model_Small'Universal_Literal_String,
6497 AAMPL_Model_Small'Universal_Literal_String);
6503 when Attribute_Modulus =>
6504 Fold_Uint (N, Modulus (P_Type), True);
6506 --------------------
6507 -- Null_Parameter --
6508 --------------------
6510 -- Cannot fold, we know the value sort of, but the whole point is
6511 -- that there is no way to talk about this imaginary value except
6512 -- by using the attribute, so we leave it the way it is.
6514 when Attribute_Null_Parameter =>
6521 -- The Object_Size attribute for a type returns the Esize of the
6522 -- type and can be folded if this value is known.
6524 when Attribute_Object_Size => Object_Size : declare
6525 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6528 if Known_Esize (P_TypeA) then
6529 Fold_Uint (N, Esize (P_TypeA), True);
6533 -------------------------
6534 -- Passed_By_Reference --
6535 -------------------------
6537 -- Scalar types are never passed by reference
6539 when Attribute_Passed_By_Reference =>
6540 Fold_Uint (N, False_Value, True);
6546 when Attribute_Pos =>
6547 Fold_Uint (N, Expr_Value (E1), True);
6553 when Attribute_Pred => Pred :
6555 -- Floating-point case
6557 if Is_Floating_Point_Type (P_Type) then
6559 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
6563 elsif Is_Fixed_Point_Type (P_Type) then
6565 Expr_Value_R (E1) - Small_Value (P_Type), True);
6567 -- Modular integer case (wraps)
6569 elsif Is_Modular_Integer_Type (P_Type) then
6570 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
6572 -- Other scalar cases
6575 pragma Assert (Is_Scalar_Type (P_Type));
6577 if Is_Enumeration_Type (P_Type)
6578 and then Expr_Value (E1) =
6579 Expr_Value (Type_Low_Bound (P_Base_Type))
6581 Apply_Compile_Time_Constraint_Error
6582 (N, "Pred of `&''First`",
6583 CE_Overflow_Check_Failed,
6585 Warn => not Static);
6591 Fold_Uint (N, Expr_Value (E1) - 1, Static);
6599 -- No processing required, because by this stage, Range has been
6600 -- replaced by First .. Last, so this branch can never be taken.
6602 when Attribute_Range =>
6603 raise Program_Error;
6609 when Attribute_Range_Length =>
6612 if Compile_Time_Known_Value (Hi_Bound)
6613 and then Compile_Time_Known_Value (Lo_Bound)
6617 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
6625 when Attribute_Remainder => Remainder : declare
6626 X : constant Ureal := Expr_Value_R (E1);
6627 Y : constant Ureal := Expr_Value_R (E2);
6630 if UR_Is_Zero (Y) then
6631 Apply_Compile_Time_Constraint_Error
6632 (N, "division by zero in Remainder",
6633 CE_Overflow_Check_Failed,
6634 Warn => not Static);
6640 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
6647 when Attribute_Round => Round :
6653 -- First we get the (exact result) in units of small
6655 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
6657 -- Now round that exactly to an integer
6659 Si := UR_To_Uint (Sr);
6661 -- Finally the result is obtained by converting back to real
6663 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
6670 when Attribute_Rounding =>
6672 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6678 when Attribute_Safe_Emax =>
6679 Float_Attribute_Universal_Integer (
6693 when Attribute_Safe_First =>
6694 Float_Attribute_Universal_Real (
6695 IEEES_Safe_First'Universal_Literal_String,
6696 IEEEL_Safe_First'Universal_Literal_String,
6697 IEEEX_Safe_First'Universal_Literal_String,
6698 VAXFF_Safe_First'Universal_Literal_String,
6699 VAXDF_Safe_First'Universal_Literal_String,
6700 VAXGF_Safe_First'Universal_Literal_String,
6701 AAMPS_Safe_First'Universal_Literal_String,
6702 AAMPL_Safe_First'Universal_Literal_String);
6708 when Attribute_Safe_Large =>
6709 if Is_Fixed_Point_Type (P_Type) then
6711 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
6713 Float_Attribute_Universal_Real (
6714 IEEES_Safe_Large'Universal_Literal_String,
6715 IEEEL_Safe_Large'Universal_Literal_String,
6716 IEEEX_Safe_Large'Universal_Literal_String,
6717 VAXFF_Safe_Large'Universal_Literal_String,
6718 VAXDF_Safe_Large'Universal_Literal_String,
6719 VAXGF_Safe_Large'Universal_Literal_String,
6720 AAMPS_Safe_Large'Universal_Literal_String,
6721 AAMPL_Safe_Large'Universal_Literal_String);
6728 when Attribute_Safe_Last =>
6729 Float_Attribute_Universal_Real (
6730 IEEES_Safe_Last'Universal_Literal_String,
6731 IEEEL_Safe_Last'Universal_Literal_String,
6732 IEEEX_Safe_Last'Universal_Literal_String,
6733 VAXFF_Safe_Last'Universal_Literal_String,
6734 VAXDF_Safe_Last'Universal_Literal_String,
6735 VAXGF_Safe_Last'Universal_Literal_String,
6736 AAMPS_Safe_Last'Universal_Literal_String,
6737 AAMPL_Safe_Last'Universal_Literal_String);
6743 when Attribute_Safe_Small =>
6745 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
6746 -- for fixed-point, since is the same as Small, but we implement
6747 -- it for backwards compatibility.
6749 if Is_Fixed_Point_Type (P_Type) then
6750 Fold_Ureal (N, Small_Value (P_Type), Static);
6752 -- Ada 83 Safe_Small for floating-point cases
6755 Float_Attribute_Universal_Real (
6756 IEEES_Safe_Small'Universal_Literal_String,
6757 IEEEL_Safe_Small'Universal_Literal_String,
6758 IEEEX_Safe_Small'Universal_Literal_String,
6759 VAXFF_Safe_Small'Universal_Literal_String,
6760 VAXDF_Safe_Small'Universal_Literal_String,
6761 VAXGF_Safe_Small'Universal_Literal_String,
6762 AAMPS_Safe_Small'Universal_Literal_String,
6763 AAMPL_Safe_Small'Universal_Literal_String);
6770 when Attribute_Scale =>
6771 Fold_Uint (N, Scale_Value (P_Type), True);
6777 when Attribute_Scaling =>
6780 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6786 when Attribute_Signed_Zeros =>
6788 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
6794 -- Size attribute returns the RM size. All scalar types can be folded,
6795 -- as well as any types for which the size is known by the front end,
6796 -- including any type for which a size attribute is specified.
6798 when Attribute_Size | Attribute_VADS_Size => Size : declare
6799 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6802 if RM_Size (P_TypeA) /= Uint_0 then
6806 if Id = Attribute_VADS_Size or else Use_VADS_Size then
6808 S : constant Node_Id := Size_Clause (P_TypeA);
6811 -- If a size clause applies, then use the size from it.
6812 -- This is one of the rare cases where we can use the
6813 -- Size_Clause field for a subtype when Has_Size_Clause
6814 -- is False. Consider:
6816 -- type x is range 1 .. 64;
6817 -- for x'size use 12;
6818 -- subtype y is x range 0 .. 3;
6820 -- Here y has a size clause inherited from x, but normally
6821 -- it does not apply, and y'size is 2. However, y'VADS_Size
6822 -- is indeed 12 and not 2.
6825 and then Is_OK_Static_Expression (Expression (S))
6827 Fold_Uint (N, Expr_Value (Expression (S)), True);
6829 -- If no size is specified, then we simply use the object
6830 -- size in the VADS_Size case (e.g. Natural'Size is equal
6831 -- to Integer'Size, not one less).
6834 Fold_Uint (N, Esize (P_TypeA), True);
6838 -- Normal case (Size) in which case we want the RM_Size
6843 Static and then Is_Discrete_Type (P_TypeA));
6852 when Attribute_Small =>
6854 -- The floating-point case is present only for Ada 83 compatibility.
6855 -- Note that strictly this is an illegal addition, since we are
6856 -- extending an Ada 95 defined attribute, but we anticipate an
6857 -- ARG ruling that will permit this.
6859 if Is_Floating_Point_Type (P_Type) then
6861 -- Ada 83 attribute is defined as (RM83 3.5.8)
6863 -- T'Small = 2.0**(-T'Emax - 1)
6867 -- T'Emax = 4 * T'Mantissa
6869 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
6871 -- Normal Ada 95 fixed-point case
6874 Fold_Ureal (N, Small_Value (P_Type), True);
6881 when Attribute_Stream_Size =>
6888 when Attribute_Succ => Succ :
6890 -- Floating-point case
6892 if Is_Floating_Point_Type (P_Type) then
6894 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
6898 elsif Is_Fixed_Point_Type (P_Type) then
6900 Expr_Value_R (E1) + Small_Value (P_Type), Static);
6902 -- Modular integer case (wraps)
6904 elsif Is_Modular_Integer_Type (P_Type) then
6905 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
6907 -- Other scalar cases
6910 pragma Assert (Is_Scalar_Type (P_Type));
6912 if Is_Enumeration_Type (P_Type)
6913 and then Expr_Value (E1) =
6914 Expr_Value (Type_High_Bound (P_Base_Type))
6916 Apply_Compile_Time_Constraint_Error
6917 (N, "Succ of `&''Last`",
6918 CE_Overflow_Check_Failed,
6920 Warn => not Static);
6925 Fold_Uint (N, Expr_Value (E1) + 1, Static);
6934 when Attribute_Truncation =>
6936 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
6942 when Attribute_Type_Class => Type_Class : declare
6943 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
6947 if Is_Descendent_Of_Address (Typ) then
6948 Id := RE_Type_Class_Address;
6950 elsif Is_Enumeration_Type (Typ) then
6951 Id := RE_Type_Class_Enumeration;
6953 elsif Is_Integer_Type (Typ) then
6954 Id := RE_Type_Class_Integer;
6956 elsif Is_Fixed_Point_Type (Typ) then
6957 Id := RE_Type_Class_Fixed_Point;
6959 elsif Is_Floating_Point_Type (Typ) then
6960 Id := RE_Type_Class_Floating_Point;
6962 elsif Is_Array_Type (Typ) then
6963 Id := RE_Type_Class_Array;
6965 elsif Is_Record_Type (Typ) then
6966 Id := RE_Type_Class_Record;
6968 elsif Is_Access_Type (Typ) then
6969 Id := RE_Type_Class_Access;
6971 elsif Is_Enumeration_Type (Typ) then
6972 Id := RE_Type_Class_Enumeration;
6974 elsif Is_Task_Type (Typ) then
6975 Id := RE_Type_Class_Task;
6977 -- We treat protected types like task types. It would make more
6978 -- sense to have another enumeration value, but after all the
6979 -- whole point of this feature is to be exactly DEC compatible,
6980 -- and changing the type Type_Class would not meet this requirement.
6982 elsif Is_Protected_Type (Typ) then
6983 Id := RE_Type_Class_Task;
6985 -- Not clear if there are any other possibilities, but if there
6986 -- are, then we will treat them as the address case.
6989 Id := RE_Type_Class_Address;
6992 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
6995 -----------------------
6996 -- Unbiased_Rounding --
6997 -----------------------
6999 when Attribute_Unbiased_Rounding =>
7001 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7004 -------------------------
7005 -- Unconstrained_Array --
7006 -------------------------
7008 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7009 Typ : constant Entity_Id := Underlying_Type (P_Type);
7012 Rewrite (N, New_Occurrence_Of (
7014 Is_Array_Type (P_Type)
7015 and then not Is_Constrained (Typ)), Loc));
7017 -- Analyze and resolve as boolean, note that this attribute is
7018 -- a static attribute in GNAT.
7020 Analyze_And_Resolve (N, Standard_Boolean);
7022 end Unconstrained_Array;
7028 -- Processing is shared with Size
7034 when Attribute_Val => Val :
7036 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7038 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7040 Apply_Compile_Time_Constraint_Error
7041 (N, "Val expression out of range",
7042 CE_Range_Check_Failed,
7043 Warn => not Static);
7049 Fold_Uint (N, Expr_Value (E1), Static);
7057 -- The Value_Size attribute for a type returns the RM size of the
7058 -- type. This an always be folded for scalar types, and can also
7059 -- be folded for non-scalar types if the size is set.
7061 when Attribute_Value_Size => Value_Size : declare
7062 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7064 if RM_Size (P_TypeA) /= Uint_0 then
7065 Fold_Uint (N, RM_Size (P_TypeA), True);
7073 -- Version can never be static
7075 when Attribute_Version =>
7082 -- Wide_Image is a scalar attribute, but is never static, because it
7083 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7085 when Attribute_Wide_Image =>
7088 ---------------------
7089 -- Wide_Wide_Image --
7090 ---------------------
7092 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7093 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7095 when Attribute_Wide_Wide_Image =>
7098 ---------------------
7099 -- Wide_Wide_Width --
7100 ---------------------
7102 -- Processing for Wide_Wide_Width is combined with Width
7108 -- Processing for Wide_Width is combined with Width
7114 -- This processing also handles the case of Wide_[Wide_]Width
7116 when Attribute_Width |
7117 Attribute_Wide_Width |
7118 Attribute_Wide_Wide_Width => Width :
7120 if Compile_Time_Known_Bounds (P_Type) then
7122 -- Floating-point types
7124 if Is_Floating_Point_Type (P_Type) then
7126 -- Width is zero for a null range (RM 3.5 (38))
7128 if Expr_Value_R (Type_High_Bound (P_Type)) <
7129 Expr_Value_R (Type_Low_Bound (P_Type))
7131 Fold_Uint (N, Uint_0, True);
7134 -- For floating-point, we have +N.dddE+nnn where length
7135 -- of ddd is determined by type'Digits - 1, but is one
7136 -- if Digits is one (RM 3.5 (33)).
7138 -- nnn is set to 2 for Short_Float and Float (32 bit
7139 -- floats), and 3 for Long_Float and Long_Long_Float.
7140 -- For machines where Long_Long_Float is the IEEE
7141 -- extended precision type, the exponent takes 4 digits.
7145 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7148 if Esize (P_Type) <= 32 then
7150 elsif Esize (P_Type) = 64 then
7156 Fold_Uint (N, UI_From_Int (Len), True);
7160 -- Fixed-point types
7162 elsif Is_Fixed_Point_Type (P_Type) then
7164 -- Width is zero for a null range (RM 3.5 (38))
7166 if Expr_Value (Type_High_Bound (P_Type)) <
7167 Expr_Value (Type_Low_Bound (P_Type))
7169 Fold_Uint (N, Uint_0, True);
7171 -- The non-null case depends on the specific real type
7174 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7177 (N, UI_From_Int (Fore_Value + 1 + Aft_Value), True);
7184 R : constant Entity_Id := Root_Type (P_Type);
7185 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7186 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7199 -- Width for types derived from Standard.Character
7200 -- and Standard.Wide_[Wide_]Character.
7202 elsif Is_Standard_Character_Type (P_Type) then
7205 -- Set W larger if needed
7207 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7209 -- All wide characters look like Hex_hhhhhhhh
7215 C := Character'Val (J);
7217 -- Test for all cases where Character'Image
7218 -- yields an image that is longer than three
7219 -- characters. First the cases of Reserved_xxx
7220 -- names (length = 12).
7223 when Reserved_128 | Reserved_129 |
7224 Reserved_132 | Reserved_153
7228 when BS | HT | LF | VT | FF | CR |
7229 SO | SI | EM | FS | GS | RS |
7230 US | RI | MW | ST | PM
7234 when NUL | SOH | STX | ETX | EOT |
7235 ENQ | ACK | BEL | DLE | DC1 |
7236 DC2 | DC3 | DC4 | NAK | SYN |
7237 ETB | CAN | SUB | ESC | DEL |
7238 BPH | NBH | NEL | SSA | ESA |
7239 HTS | HTJ | VTS | PLD | PLU |
7240 SS2 | SS3 | DCS | PU1 | PU2 |
7241 STS | CCH | SPA | EPA | SOS |
7242 SCI | CSI | OSC | APC
7246 when Space .. Tilde |
7247 No_Break_Space .. LC_Y_Diaeresis
7252 W := Int'Max (W, Wt);
7256 -- Width for types derived from Standard.Boolean
7258 elsif R = Standard_Boolean then
7265 -- Width for integer types
7267 elsif Is_Integer_Type (P_Type) then
7268 T := UI_Max (abs Lo, abs Hi);
7276 -- Only remaining possibility is user declared enum type
7279 pragma Assert (Is_Enumeration_Type (P_Type));
7282 L := First_Literal (P_Type);
7284 while Present (L) loop
7286 -- Only pay attention to in range characters
7288 if Lo <= Enumeration_Pos (L)
7289 and then Enumeration_Pos (L) <= Hi
7291 -- For Width case, use decoded name
7293 if Id = Attribute_Width then
7294 Get_Decoded_Name_String (Chars (L));
7295 Wt := Nat (Name_Len);
7297 -- For Wide_[Wide_]Width, use encoded name, and
7298 -- then adjust for the encoding.
7301 Get_Name_String (Chars (L));
7303 -- Character literals are always of length 3
7305 if Name_Buffer (1) = 'Q' then
7308 -- Otherwise loop to adjust for upper/wide chars
7311 Wt := Nat (Name_Len);
7313 for J in 1 .. Name_Len loop
7314 if Name_Buffer (J) = 'U' then
7316 elsif Name_Buffer (J) = 'W' then
7323 W := Int'Max (W, Wt);
7330 Fold_Uint (N, UI_From_Int (W), True);
7336 -- The following attributes denote function that cannot be folded
7338 when Attribute_From_Any |
7340 Attribute_TypeCode =>
7343 -- The following attributes can never be folded, and furthermore we
7344 -- should not even have entered the case statement for any of these.
7345 -- Note that in some cases, the values have already been folded as
7346 -- a result of the processing in Analyze_Attribute.
7348 when Attribute_Abort_Signal |
7351 Attribute_Address_Size |
7352 Attribute_Asm_Input |
7353 Attribute_Asm_Output |
7355 Attribute_Bit_Order |
7356 Attribute_Bit_Position |
7357 Attribute_Callable |
7360 Attribute_Code_Address |
7362 Attribute_Default_Bit_Order |
7363 Attribute_Elaborated |
7364 Attribute_Elab_Body |
7365 Attribute_Elab_Spec |
7367 Attribute_External_Tag |
7368 Attribute_Fast_Math |
7369 Attribute_First_Bit |
7371 Attribute_Last_Bit |
7372 Attribute_Maximum_Alignment |
7375 Attribute_Partition_ID |
7376 Attribute_Pool_Address |
7377 Attribute_Position |
7378 Attribute_Priority |
7381 Attribute_Storage_Pool |
7382 Attribute_Storage_Size |
7383 Attribute_Storage_Unit |
7384 Attribute_Stub_Type |
7386 Attribute_Target_Name |
7387 Attribute_Terminated |
7388 Attribute_To_Address |
7389 Attribute_UET_Address |
7390 Attribute_Unchecked_Access |
7391 Attribute_Universal_Literal_String |
7392 Attribute_Unrestricted_Access |
7395 Attribute_Wchar_T_Size |
7396 Attribute_Wide_Value |
7397 Attribute_Wide_Wide_Value |
7398 Attribute_Word_Size |
7401 raise Program_Error;
7404 -- At the end of the case, one more check. If we did a static evaluation
7405 -- so that the result is now a literal, then set Is_Static_Expression
7406 -- in the constant only if the prefix type is a static subtype. For
7407 -- non-static subtypes, the folding is still OK, but not static.
7409 -- An exception is the GNAT attribute Constrained_Array which is
7410 -- defined to be a static attribute in all cases.
7412 if Nkind_In (N, N_Integer_Literal,
7414 N_Character_Literal,
7416 or else (Is_Entity_Name (N)
7417 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7419 Set_Is_Static_Expression (N, Static);
7421 -- If this is still an attribute reference, then it has not been folded
7422 -- and that means that its expressions are in a non-static context.
7424 elsif Nkind (N) = N_Attribute_Reference then
7427 -- Note: the else case not covered here are odd cases where the
7428 -- processing has transformed the attribute into something other
7429 -- than a constant. Nothing more to do in such cases.
7436 ------------------------------
7437 -- Is_Anonymous_Tagged_Base --
7438 ------------------------------
7440 function Is_Anonymous_Tagged_Base
7447 Anon = Current_Scope
7448 and then Is_Itype (Anon)
7449 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
7450 end Is_Anonymous_Tagged_Base;
7452 --------------------------------
7453 -- Name_Implies_Lvalue_Prefix --
7454 --------------------------------
7456 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
7457 pragma Assert (Is_Attribute_Name (Nam));
7459 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
7460 end Name_Implies_Lvalue_Prefix;
7462 -----------------------
7463 -- Resolve_Attribute --
7464 -----------------------
7466 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
7467 Loc : constant Source_Ptr := Sloc (N);
7468 P : constant Node_Id := Prefix (N);
7469 Aname : constant Name_Id := Attribute_Name (N);
7470 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7471 Btyp : constant Entity_Id := Base_Type (Typ);
7472 Des_Btyp : Entity_Id;
7473 Index : Interp_Index;
7475 Nom_Subt : Entity_Id;
7477 procedure Accessibility_Message;
7478 -- Error, or warning within an instance, if the static accessibility
7479 -- rules of 3.10.2 are violated.
7481 ---------------------------
7482 -- Accessibility_Message --
7483 ---------------------------
7485 procedure Accessibility_Message is
7486 Indic : Node_Id := Parent (Parent (N));
7489 -- In an instance, this is a runtime check, but one we
7490 -- know will fail, so generate an appropriate warning.
7492 if In_Instance_Body then
7494 ("?non-local pointer cannot point to local object", P);
7496 ("\?Program_Error will be raised at run time", P);
7498 Make_Raise_Program_Error (Loc,
7499 Reason => PE_Accessibility_Check_Failed));
7505 ("non-local pointer cannot point to local object", P);
7507 -- Check for case where we have a missing access definition
7509 if Is_Record_Type (Current_Scope)
7511 Nkind_In (Parent (N), N_Discriminant_Association,
7512 N_Index_Or_Discriminant_Constraint)
7514 Indic := Parent (Parent (N));
7515 while Present (Indic)
7516 and then Nkind (Indic) /= N_Subtype_Indication
7518 Indic := Parent (Indic);
7521 if Present (Indic) then
7523 ("\use an access definition for" &
7524 " the access discriminant of&",
7525 N, Entity (Subtype_Mark (Indic)));
7529 end Accessibility_Message;
7531 -- Start of processing for Resolve_Attribute
7534 -- If error during analysis, no point in continuing, except for
7535 -- array types, where we get better recovery by using unconstrained
7536 -- indices than nothing at all (see Check_Array_Type).
7539 and then Attr_Id /= Attribute_First
7540 and then Attr_Id /= Attribute_Last
7541 and then Attr_Id /= Attribute_Length
7542 and then Attr_Id /= Attribute_Range
7547 -- If attribute was universal type, reset to actual type
7549 if Etype (N) = Universal_Integer
7550 or else Etype (N) = Universal_Real
7555 -- Remaining processing depends on attribute
7563 -- For access attributes, if the prefix denotes an entity, it is
7564 -- interpreted as a name, never as a call. It may be overloaded,
7565 -- in which case resolution uses the profile of the context type.
7566 -- Otherwise prefix must be resolved.
7568 when Attribute_Access
7569 | Attribute_Unchecked_Access
7570 | Attribute_Unrestricted_Access =>
7574 if Is_Variable (P) then
7575 Note_Possible_Modification (P, Sure => False);
7578 -- The following comes from a query by Adam Beneschan, concerning
7579 -- improper use of universal_access in equality tests involving
7580 -- anonymous access types. Another good reason for 'Ref, but
7581 -- for now disable the test, which breaks several filed tests.
7583 if Ekind (Typ) = E_Anonymous_Access_Type
7584 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
7587 Error_Msg_N ("need unique type to resolve 'Access", N);
7588 Error_Msg_N ("\qualify attribute with some access type", N);
7591 if Is_Entity_Name (P) then
7592 if Is_Overloaded (P) then
7593 Get_First_Interp (P, Index, It);
7594 while Present (It.Nam) loop
7595 if Type_Conformant (Designated_Type (Typ), It.Nam) then
7596 Set_Entity (P, It.Nam);
7598 -- The prefix is definitely NOT overloaded anymore at
7599 -- this point, so we reset the Is_Overloaded flag to
7600 -- avoid any confusion when reanalyzing the node.
7602 Set_Is_Overloaded (P, False);
7603 Set_Is_Overloaded (N, False);
7604 Generate_Reference (Entity (P), P);
7608 Get_Next_Interp (Index, It);
7611 -- If Prefix is a subprogram name, it is frozen by this
7614 -- If it is a type, there is nothing to resolve.
7615 -- If it is an object, complete its resolution.
7617 elsif Is_Overloadable (Entity (P)) then
7619 -- Avoid insertion of freeze actions in spec expression mode
7621 if not In_Spec_Expression then
7622 Insert_Actions (N, Freeze_Entity (Entity (P), Loc));
7625 elsif Is_Type (Entity (P)) then
7631 Error_Msg_Name_1 := Aname;
7633 if not Is_Entity_Name (P) then
7636 elsif Is_Overloadable (Entity (P))
7637 and then Is_Abstract_Subprogram (Entity (P))
7639 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
7640 Set_Etype (N, Any_Type);
7642 elsif Convention (Entity (P)) = Convention_Intrinsic then
7643 if Ekind (Entity (P)) = E_Enumeration_Literal then
7645 ("prefix of % attribute cannot be enumeration literal",
7649 ("prefix of % attribute cannot be intrinsic", P);
7652 Set_Etype (N, Any_Type);
7655 -- Assignments, return statements, components of aggregates,
7656 -- generic instantiations will require convention checks if
7657 -- the type is an access to subprogram. Given that there will
7658 -- also be accessibility checks on those, this is where the
7659 -- checks can eventually be centralized ???
7661 if Ekind (Btyp) = E_Access_Subprogram_Type
7663 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
7665 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type
7667 -- Deal with convention mismatch
7669 if Convention (Btyp) /= Convention (Entity (P)) then
7671 ("subprogram & has wrong convention", P, Entity (P));
7674 ("\does not match convention of access type &",
7677 if not Has_Convention_Pragma (Btyp) then
7679 ("\probable missing pragma Convention for &",
7684 Check_Subtype_Conformant
7685 (New_Id => Entity (P),
7686 Old_Id => Designated_Type (Btyp),
7690 if Attr_Id = Attribute_Unchecked_Access then
7691 Error_Msg_Name_1 := Aname;
7693 ("attribute% cannot be applied to a subprogram", P);
7695 elsif Aname = Name_Unrestricted_Access then
7696 null; -- Nothing to check
7698 -- Check the static accessibility rule of 3.10.2(32).
7699 -- This rule also applies within the private part of an
7700 -- instantiation. This rule does not apply to anonymous
7701 -- access-to-subprogram types (Ada 2005).
7703 elsif Attr_Id = Attribute_Access
7704 and then not In_Instance_Body
7705 and then Subprogram_Access_Level (Entity (P)) >
7706 Type_Access_Level (Btyp)
7707 and then Ekind (Btyp) /=
7708 E_Anonymous_Access_Subprogram_Type
7709 and then Ekind (Btyp) /=
7710 E_Anonymous_Access_Protected_Subprogram_Type
7713 ("subprogram must not be deeper than access type", P);
7715 -- Check the restriction of 3.10.2(32) that disallows the
7716 -- access attribute within a generic body when the ultimate
7717 -- ancestor of the type of the attribute is declared outside
7718 -- of the generic unit and the subprogram is declared within
7719 -- that generic unit. This includes any such attribute that
7720 -- occurs within the body of a generic unit that is a child
7721 -- of the generic unit where the subprogram is declared.
7722 -- The rule also prohibits applying the attribute when the
7723 -- access type is a generic formal access type (since the
7724 -- level of the actual type is not known). This restriction
7725 -- does not apply when the attribute type is an anonymous
7726 -- access-to-subprogram type. Note that this check was
7727 -- revised by AI-229, because the originally Ada 95 rule
7728 -- was too lax. The original rule only applied when the
7729 -- subprogram was declared within the body of the generic,
7730 -- which allowed the possibility of dangling references).
7731 -- The rule was also too strict in some case, in that it
7732 -- didn't permit the access to be declared in the generic
7733 -- spec, whereas the revised rule does (as long as it's not
7736 -- There are a couple of subtleties of the test for applying
7737 -- the check that are worth noting. First, we only apply it
7738 -- when the levels of the subprogram and access type are the
7739 -- same (the case where the subprogram is statically deeper
7740 -- was applied above, and the case where the type is deeper
7741 -- is always safe). Second, we want the check to apply
7742 -- within nested generic bodies and generic child unit
7743 -- bodies, but not to apply to an attribute that appears in
7744 -- the generic unit's specification. This is done by testing
7745 -- that the attribute's innermost enclosing generic body is
7746 -- not the same as the innermost generic body enclosing the
7747 -- generic unit where the subprogram is declared (we don't
7748 -- want the check to apply when the access attribute is in
7749 -- the spec and there's some other generic body enclosing
7750 -- generic). Finally, there's no point applying the check
7751 -- when within an instance, because any violations will have
7752 -- been caught by the compilation of the generic unit.
7754 elsif Attr_Id = Attribute_Access
7755 and then not In_Instance
7756 and then Present (Enclosing_Generic_Unit (Entity (P)))
7757 and then Present (Enclosing_Generic_Body (N))
7758 and then Enclosing_Generic_Body (N) /=
7759 Enclosing_Generic_Body
7760 (Enclosing_Generic_Unit (Entity (P)))
7761 and then Subprogram_Access_Level (Entity (P)) =
7762 Type_Access_Level (Btyp)
7763 and then Ekind (Btyp) /=
7764 E_Anonymous_Access_Subprogram_Type
7765 and then Ekind (Btyp) /=
7766 E_Anonymous_Access_Protected_Subprogram_Type
7768 -- The attribute type's ultimate ancestor must be
7769 -- declared within the same generic unit as the
7770 -- subprogram is declared. The error message is
7771 -- specialized to say "ancestor" for the case where
7772 -- the access type is not its own ancestor, since
7773 -- saying simply "access type" would be very confusing.
7775 if Enclosing_Generic_Unit (Entity (P)) /=
7776 Enclosing_Generic_Unit (Root_Type (Btyp))
7779 ("''Access attribute not allowed in generic body",
7782 if Root_Type (Btyp) = Btyp then
7785 "access type & is declared outside " &
7786 "generic unit (RM 3.10.2(32))", N, Btyp);
7789 ("\because ancestor of " &
7790 "access type & is declared outside " &
7791 "generic unit (RM 3.10.2(32))", N, Btyp);
7795 ("\move ''Access to private part, or " &
7796 "(Ada 2005) use anonymous access type instead of &",
7799 -- If the ultimate ancestor of the attribute's type is
7800 -- a formal type, then the attribute is illegal because
7801 -- the actual type might be declared at a higher level.
7802 -- The error message is specialized to say "ancestor"
7803 -- for the case where the access type is not its own
7804 -- ancestor, since saying simply "access type" would be
7807 elsif Is_Generic_Type (Root_Type (Btyp)) then
7808 if Root_Type (Btyp) = Btyp then
7810 ("access type must not be a generic formal type",
7814 ("ancestor access type must not be a generic " &
7821 -- If this is a renaming, an inherited operation, or a
7822 -- subprogram instance, use the original entity. This may make
7823 -- the node type-inconsistent, so this transformation can only
7824 -- be done if the node will not be reanalyzed. In particular,
7825 -- if it is within a default expression, the transformation
7826 -- must be delayed until the default subprogram is created for
7827 -- it, when the enclosing subprogram is frozen.
7829 if Is_Entity_Name (P)
7830 and then Is_Overloadable (Entity (P))
7831 and then Present (Alias (Entity (P)))
7832 and then Expander_Active
7835 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
7838 elsif Nkind (P) = N_Selected_Component
7839 and then Is_Overloadable (Entity (Selector_Name (P)))
7841 -- Protected operation. If operation is overloaded, must
7842 -- disambiguate. Prefix that denotes protected object itself
7843 -- is resolved with its own type.
7845 if Attr_Id = Attribute_Unchecked_Access then
7846 Error_Msg_Name_1 := Aname;
7848 ("attribute% cannot be applied to protected operation", P);
7851 Resolve (Prefix (P));
7852 Generate_Reference (Entity (Selector_Name (P)), P);
7854 elsif Is_Overloaded (P) then
7856 -- Use the designated type of the context to disambiguate
7857 -- Note that this was not strictly conformant to Ada 95,
7858 -- but was the implementation adopted by most Ada 95 compilers.
7859 -- The use of the context type to resolve an Access attribute
7860 -- reference is now mandated in AI-235 for Ada 2005.
7863 Index : Interp_Index;
7867 Get_First_Interp (P, Index, It);
7868 while Present (It.Typ) loop
7869 if Covers (Designated_Type (Typ), It.Typ) then
7870 Resolve (P, It.Typ);
7874 Get_Next_Interp (Index, It);
7881 -- X'Access is illegal if X denotes a constant and the access type
7882 -- is access-to-variable. Same for 'Unchecked_Access. The rule
7883 -- does not apply to 'Unrestricted_Access. If the reference is a
7884 -- default-initialized aggregate component for a self-referential
7885 -- type the reference is legal.
7887 if not (Ekind (Btyp) = E_Access_Subprogram_Type
7888 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
7889 or else (Is_Record_Type (Btyp)
7891 Present (Corresponding_Remote_Type (Btyp)))
7892 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
7893 or else Ekind (Btyp)
7894 = E_Anonymous_Access_Protected_Subprogram_Type
7895 or else Is_Access_Constant (Btyp)
7896 or else Is_Variable (P)
7897 or else Attr_Id = Attribute_Unrestricted_Access)
7899 if Is_Entity_Name (P)
7900 and then Is_Type (Entity (P))
7902 -- Legality of a self-reference through an access
7903 -- attribute has been verified in Analyze_Access_Attribute.
7907 elsif Comes_From_Source (N) then
7908 Error_Msg_F ("access-to-variable designates constant", P);
7912 Des_Btyp := Designated_Type (Btyp);
7914 if Ada_Version >= Ada_05
7915 and then Is_Incomplete_Type (Des_Btyp)
7917 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
7918 -- imported entity, and the non-limited view is visible, make
7919 -- use of it. If it is an incomplete subtype, use the base type
7922 if From_With_Type (Des_Btyp)
7923 and then Present (Non_Limited_View (Des_Btyp))
7925 Des_Btyp := Non_Limited_View (Des_Btyp);
7927 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
7928 Des_Btyp := Etype (Des_Btyp);
7932 if (Attr_Id = Attribute_Access
7934 Attr_Id = Attribute_Unchecked_Access)
7935 and then (Ekind (Btyp) = E_General_Access_Type
7936 or else Ekind (Btyp) = E_Anonymous_Access_Type)
7938 -- Ada 2005 (AI-230): Check the accessibility of anonymous
7939 -- access types for stand-alone objects, record and array
7940 -- components, and return objects. For a component definition
7941 -- the level is the same of the enclosing composite type.
7943 if Ada_Version >= Ada_05
7944 and then Is_Local_Anonymous_Access (Btyp)
7945 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
7946 and then Attr_Id = Attribute_Access
7948 -- In an instance, this is a runtime check, but one we
7949 -- know will fail, so generate an appropriate warning.
7951 if In_Instance_Body then
7953 ("?non-local pointer cannot point to local object", P);
7955 ("\?Program_Error will be raised at run time", P);
7957 Make_Raise_Program_Error (Loc,
7958 Reason => PE_Accessibility_Check_Failed));
7963 ("non-local pointer cannot point to local object", P);
7967 if Is_Dependent_Component_Of_Mutable_Object (P) then
7969 ("illegal attribute for discriminant-dependent component",
7973 -- Check static matching rule of 3.10.2(27). Nominal subtype
7974 -- of the prefix must statically match the designated type.
7976 Nom_Subt := Etype (P);
7978 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
7979 Nom_Subt := Base_Type (Nom_Subt);
7982 if Is_Tagged_Type (Designated_Type (Typ)) then
7984 -- If the attribute is in the context of an access
7985 -- parameter, then the prefix is allowed to be of the
7986 -- class-wide type (by AI-127).
7988 if Ekind (Typ) = E_Anonymous_Access_Type then
7989 if not Covers (Designated_Type (Typ), Nom_Subt)
7990 and then not Covers (Nom_Subt, Designated_Type (Typ))
7996 Desig := Designated_Type (Typ);
7998 if Is_Class_Wide_Type (Desig) then
7999 Desig := Etype (Desig);
8002 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8007 ("type of prefix: & not compatible",
8010 ("\with &, the expected designated type",
8011 P, Designated_Type (Typ));
8016 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8018 (not Is_Class_Wide_Type (Designated_Type (Typ))
8019 and then Is_Class_Wide_Type (Nom_Subt))
8022 ("type of prefix: & is not covered", P, Nom_Subt);
8024 ("\by &, the expected designated type" &
8025 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8028 if Is_Class_Wide_Type (Designated_Type (Typ))
8029 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8030 and then Is_Constrained (Etype (Designated_Type (Typ)))
8031 and then Designated_Type (Typ) /= Nom_Subt
8033 Apply_Discriminant_Check
8034 (N, Etype (Designated_Type (Typ)));
8037 -- Ada 2005 (AI-363): Require static matching when designated
8038 -- type has discriminants and a constrained partial view, since
8039 -- in general objects of such types are mutable, so we can't
8040 -- allow the access value to designate a constrained object
8041 -- (because access values must be assumed to designate mutable
8042 -- objects when designated type does not impose a constraint).
8044 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8047 elsif Has_Discriminants (Designated_Type (Typ))
8048 and then not Is_Constrained (Des_Btyp)
8050 (Ada_Version < Ada_05
8052 not Has_Constrained_Partial_View
8053 (Designated_Type (Base_Type (Typ))))
8059 ("object subtype must statically match "
8060 & "designated subtype", P);
8062 if Is_Entity_Name (P)
8063 and then Is_Array_Type (Designated_Type (Typ))
8066 D : constant Node_Id := Declaration_Node (Entity (P));
8069 Error_Msg_N ("aliased object has explicit bounds?",
8071 Error_Msg_N ("\declare without bounds"
8072 & " (and with explicit initialization)?", D);
8073 Error_Msg_N ("\for use with unconstrained access?", D);
8078 -- Check the static accessibility rule of 3.10.2(28).
8079 -- Note that this check is not performed for the
8080 -- case of an anonymous access type, since the access
8081 -- attribute is always legal in such a context.
8083 if Attr_Id /= Attribute_Unchecked_Access
8084 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8085 and then Ekind (Btyp) = E_General_Access_Type
8087 Accessibility_Message;
8092 if Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8094 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type
8096 if Is_Entity_Name (P)
8097 and then not Is_Protected_Type (Scope (Entity (P)))
8099 Error_Msg_F ("context requires a protected subprogram", P);
8101 -- Check accessibility of protected object against that of the
8102 -- access type, but only on user code, because the expander
8103 -- creates access references for handlers. If the context is an
8104 -- anonymous_access_to_protected, there are no accessibility
8105 -- checks either. Omit check entirely for Unrestricted_Access.
8107 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8108 and then Comes_From_Source (N)
8109 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8110 and then Attr_Id /= Attribute_Unrestricted_Access
8112 Accessibility_Message;
8116 elsif (Ekind (Btyp) = E_Access_Subprogram_Type
8118 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type)
8119 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8121 Error_Msg_F ("context requires a non-protected subprogram", P);
8124 -- The context cannot be a pool-specific type, but this is a
8125 -- legality rule, not a resolution rule, so it must be checked
8126 -- separately, after possibly disambiguation (see AI-245).
8128 if Ekind (Btyp) = E_Access_Type
8129 and then Attr_Id /= Attribute_Unrestricted_Access
8131 Wrong_Type (N, Typ);
8134 -- The context may be a constrained access type (however ill-
8135 -- advised such subtypes might be) so in order to generate a
8136 -- constraint check when needed set the type of the attribute
8137 -- reference to the base type of the context.
8139 Set_Etype (N, Btyp);
8141 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8143 if Attr_Id /= Attribute_Unrestricted_Access then
8144 if Is_Atomic_Object (P)
8145 and then not Is_Atomic (Designated_Type (Typ))
8148 ("access to atomic object cannot yield access-to-" &
8149 "non-atomic type", P);
8151 elsif Is_Volatile_Object (P)
8152 and then not Is_Volatile (Designated_Type (Typ))
8155 ("access to volatile object cannot yield access-to-" &
8156 "non-volatile type", P);
8160 if Is_Entity_Name (P) then
8161 Set_Address_Taken (Entity (P));
8163 end Access_Attribute;
8169 -- Deal with resolving the type for Address attribute, overloading
8170 -- is not permitted here, since there is no context to resolve it.
8172 when Attribute_Address | Attribute_Code_Address =>
8173 Address_Attribute : begin
8175 -- To be safe, assume that if the address of a variable is taken,
8176 -- it may be modified via this address, so note modification.
8178 if Is_Variable (P) then
8179 Note_Possible_Modification (P, Sure => False);
8182 if Nkind (P) in N_Subexpr
8183 and then Is_Overloaded (P)
8185 Get_First_Interp (P, Index, It);
8186 Get_Next_Interp (Index, It);
8188 if Present (It.Nam) then
8189 Error_Msg_Name_1 := Aname;
8191 ("prefix of % attribute cannot be overloaded", P);
8195 if not Is_Entity_Name (P)
8196 or else not Is_Overloadable (Entity (P))
8198 if not Is_Task_Type (Etype (P))
8199 or else Nkind (P) = N_Explicit_Dereference
8205 -- If this is the name of a derived subprogram, or that of a
8206 -- generic actual, the address is that of the original entity.
8208 if Is_Entity_Name (P)
8209 and then Is_Overloadable (Entity (P))
8210 and then Present (Alias (Entity (P)))
8213 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8216 if Is_Entity_Name (P) then
8217 Set_Address_Taken (Entity (P));
8220 if Nkind (P) = N_Slice then
8222 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8223 -- even if the array is packed and the slice itself is not
8224 -- addressable. Transform the prefix into an indexed component.
8226 -- Note that the transformation is safe only if we know that
8227 -- the slice is non-null. That is because a null slice can have
8228 -- an out of bounds index value.
8230 -- Right now, gigi blows up if given 'Address on a slice as a
8231 -- result of some incorrect freeze nodes generated by the front
8232 -- end, and this covers up that bug in one case, but the bug is
8233 -- likely still there in the cases not handled by this code ???
8235 -- It's not clear what 'Address *should* return for a null
8236 -- slice with out of bounds indexes, this might be worth an ARG
8239 -- One approach would be to do a length check unconditionally,
8240 -- and then do the transformation below unconditionally, but
8241 -- analyze with checks off, avoiding the problem of the out of
8242 -- bounds index. This approach would interpret the address of
8243 -- an out of bounds null slice as being the address where the
8244 -- array element would be if there was one, which is probably
8245 -- as reasonable an interpretation as any ???
8248 Loc : constant Source_Ptr := Sloc (P);
8249 D : constant Node_Id := Discrete_Range (P);
8253 if Is_Entity_Name (D)
8256 (Type_Low_Bound (Entity (D)),
8257 Type_High_Bound (Entity (D)))
8260 Make_Attribute_Reference (Loc,
8261 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8262 Attribute_Name => Name_First);
8264 elsif Nkind (D) = N_Range
8265 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8267 Lo := Low_Bound (D);
8273 if Present (Lo) then
8275 Make_Indexed_Component (Loc,
8276 Prefix => Relocate_Node (Prefix (P)),
8277 Expressions => New_List (Lo)));
8279 Analyze_And_Resolve (P);
8283 end Address_Attribute;
8289 -- Prefix of the AST_Entry attribute is an entry name which must
8290 -- not be resolved, since this is definitely not an entry call.
8292 when Attribute_AST_Entry =>
8299 -- Prefix of Body_Version attribute can be a subprogram name which
8300 -- must not be resolved, since this is not a call.
8302 when Attribute_Body_Version =>
8309 -- Prefix of Caller attribute is an entry name which must not
8310 -- be resolved, since this is definitely not an entry call.
8312 when Attribute_Caller =>
8319 -- Shares processing with Address attribute
8325 -- If the prefix of the Count attribute is an entry name it must not
8326 -- be resolved, since this is definitely not an entry call. However,
8327 -- if it is an element of an entry family, the index itself may
8328 -- have to be resolved because it can be a general expression.
8330 when Attribute_Count =>
8331 if Nkind (P) = N_Indexed_Component
8332 and then Is_Entity_Name (Prefix (P))
8335 Indx : constant Node_Id := First (Expressions (P));
8336 Fam : constant Entity_Id := Entity (Prefix (P));
8338 Resolve (Indx, Entry_Index_Type (Fam));
8339 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8347 -- Prefix of the Elaborated attribute is a subprogram name which
8348 -- must not be resolved, since this is definitely not a call. Note
8349 -- that it is a library unit, so it cannot be overloaded here.
8351 when Attribute_Elaborated =>
8358 -- Prefix of Enabled attribute is a check name, which must be treated
8359 -- specially and not touched by Resolve.
8361 when Attribute_Enabled =>
8364 --------------------
8365 -- Mechanism_Code --
8366 --------------------
8368 -- Prefix of the Mechanism_Code attribute is a function name
8369 -- which must not be resolved. Should we check for overloaded ???
8371 when Attribute_Mechanism_Code =>
8378 -- Most processing is done in sem_dist, after determining the
8379 -- context type. Node is rewritten as a conversion to a runtime call.
8381 when Attribute_Partition_ID =>
8382 Process_Partition_Id (N);
8389 when Attribute_Pool_Address =>
8396 -- We replace the Range attribute node with a range expression
8397 -- whose bounds are the 'First and 'Last attributes applied to the
8398 -- same prefix. The reason that we do this transformation here
8399 -- instead of in the expander is that it simplifies other parts of
8400 -- the semantic analysis which assume that the Range has been
8401 -- replaced; thus it must be done even when in semantic-only mode
8402 -- (note that the RM specifically mentions this equivalence, we
8403 -- take care that the prefix is only evaluated once).
8405 when Attribute_Range => Range_Attribute :
8411 if not Is_Entity_Name (P)
8412 or else not Is_Type (Entity (P))
8418 Make_Attribute_Reference (Loc,
8420 Duplicate_Subexpr (P, Name_Req => True),
8421 Attribute_Name => Name_Last,
8422 Expressions => Expressions (N));
8425 Make_Attribute_Reference (Loc,
8427 Attribute_Name => Name_First,
8428 Expressions => Expressions (N));
8430 -- If the original was marked as Must_Not_Freeze (see code
8431 -- in Sem_Ch3.Make_Index), then make sure the rewriting
8432 -- does not freeze either.
8434 if Must_Not_Freeze (N) then
8435 Set_Must_Not_Freeze (HB);
8436 Set_Must_Not_Freeze (LB);
8437 Set_Must_Not_Freeze (Prefix (HB));
8438 Set_Must_Not_Freeze (Prefix (LB));
8441 if Raises_Constraint_Error (Prefix (N)) then
8443 -- Preserve Sloc of prefix in the new bounds, so that
8444 -- the posted warning can be removed if we are within
8445 -- unreachable code.
8447 Set_Sloc (LB, Sloc (Prefix (N)));
8448 Set_Sloc (HB, Sloc (Prefix (N)));
8451 Rewrite (N, Make_Range (Loc, LB, HB));
8452 Analyze_And_Resolve (N, Typ);
8454 -- Normally after resolving attribute nodes, Eval_Attribute
8455 -- is called to do any possible static evaluation of the node.
8456 -- However, here since the Range attribute has just been
8457 -- transformed into a range expression it is no longer an
8458 -- attribute node and therefore the call needs to be avoided
8459 -- and is accomplished by simply returning from the procedure.
8462 end Range_Attribute;
8468 -- We will only come here during the prescan of a spec expression
8469 -- containing a Result attribute. In that case the proper Etype has
8470 -- already been set, and nothing more needs to be done here.
8472 when Attribute_Result =>
8479 -- Prefix must not be resolved in this case, since it is not a
8480 -- real entity reference. No action of any kind is require!
8482 when Attribute_UET_Address =>
8485 ----------------------
8486 -- Unchecked_Access --
8487 ----------------------
8489 -- Processing is shared with Access
8491 -------------------------
8492 -- Unrestricted_Access --
8493 -------------------------
8495 -- Processing is shared with Access
8501 -- Apply range check. Note that we did not do this during the
8502 -- analysis phase, since we wanted Eval_Attribute to have a
8503 -- chance at finding an illegal out of range value.
8505 when Attribute_Val =>
8507 -- Note that we do our own Eval_Attribute call here rather than
8508 -- use the common one, because we need to do processing after
8509 -- the call, as per above comment.
8513 -- Eval_Attribute may replace the node with a raise CE, or
8514 -- fold it to a constant. Obviously we only apply a scalar
8515 -- range check if this did not happen!
8517 if Nkind (N) = N_Attribute_Reference
8518 and then Attribute_Name (N) = Name_Val
8520 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
8529 -- Prefix of Version attribute can be a subprogram name which
8530 -- must not be resolved, since this is not a call.
8532 when Attribute_Version =>
8535 ----------------------
8536 -- Other Attributes --
8537 ----------------------
8539 -- For other attributes, resolve prefix unless it is a type. If
8540 -- the attribute reference itself is a type name ('Base and 'Class)
8541 -- then this is only legal within a task or protected record.
8544 if not Is_Entity_Name (P)
8545 or else not Is_Type (Entity (P))
8550 -- If the attribute reference itself is a type name ('Base,
8551 -- 'Class) then this is only legal within a task or protected
8552 -- record. What is this all about ???
8554 if Is_Entity_Name (N)
8555 and then Is_Type (Entity (N))
8557 if Is_Concurrent_Type (Entity (N))
8558 and then In_Open_Scopes (Entity (P))
8563 ("invalid use of subtype name in expression or call", N);
8567 -- For attributes whose argument may be a string, complete
8568 -- resolution of argument now. This avoids premature expansion
8569 -- (and the creation of transient scopes) before the attribute
8570 -- reference is resolved.
8573 when Attribute_Value =>
8574 Resolve (First (Expressions (N)), Standard_String);
8576 when Attribute_Wide_Value =>
8577 Resolve (First (Expressions (N)), Standard_Wide_String);
8579 when Attribute_Wide_Wide_Value =>
8580 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
8582 when others => null;
8585 -- If the prefix of the attribute is a class-wide type then it
8586 -- will be expanded into a dispatching call to a predefined
8587 -- primitive. Therefore we must check for potential violation
8588 -- of such restriction.
8590 if Is_Class_Wide_Type (Etype (P)) then
8591 Check_Restriction (No_Dispatching_Calls, N);
8595 -- Normally the Freezing is done by Resolve but sometimes the Prefix
8596 -- is not resolved, in which case the freezing must be done now.
8598 Freeze_Expression (P);
8600 -- Finally perform static evaluation on the attribute reference
8603 end Resolve_Attribute;
8605 --------------------------------
8606 -- Stream_Attribute_Available --
8607 --------------------------------
8609 function Stream_Attribute_Available
8611 Nam : TSS_Name_Type;
8612 Partial_View : Node_Id := Empty) return Boolean
8614 Etyp : Entity_Id := Typ;
8616 -- Start of processing for Stream_Attribute_Available
8619 -- We need some comments in this body ???
8621 if Has_Stream_Attribute_Definition (Typ, Nam) then
8625 if Is_Class_Wide_Type (Typ) then
8626 return not Is_Limited_Type (Typ)
8627 or else Stream_Attribute_Available (Etype (Typ), Nam);
8630 if Nam = TSS_Stream_Input
8631 and then Is_Abstract_Type (Typ)
8632 and then not Is_Class_Wide_Type (Typ)
8637 if not (Is_Limited_Type (Typ)
8638 or else (Present (Partial_View)
8639 and then Is_Limited_Type (Partial_View)))
8644 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
8646 if Nam = TSS_Stream_Input
8647 and then Ada_Version >= Ada_05
8648 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
8652 elsif Nam = TSS_Stream_Output
8653 and then Ada_Version >= Ada_05
8654 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
8659 -- Case of Read and Write: check for attribute definition clause that
8660 -- applies to an ancestor type.
8662 while Etype (Etyp) /= Etyp loop
8663 Etyp := Etype (Etyp);
8665 if Has_Stream_Attribute_Definition (Etyp, Nam) then
8670 if Ada_Version < Ada_05 then
8672 -- In Ada 95 mode, also consider a non-visible definition
8675 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
8678 and then Stream_Attribute_Available
8679 (Btyp, Nam, Partial_View => Typ);
8684 end Stream_Attribute_Available;