1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, 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 Gnatvsn; use Gnatvsn;
39 with Itypes; use Itypes;
41 with Lib.Xref; use Lib.Xref;
42 with Nlists; use Nlists;
43 with Nmake; use Nmake;
45 with Restrict; use Restrict;
46 with Rident; use Rident;
47 with Rtsfind; use Rtsfind;
48 with Sdefault; use Sdefault;
50 with Sem_Aux; use Sem_Aux;
51 with Sem_Cat; use Sem_Cat;
52 with Sem_Ch6; use Sem_Ch6;
53 with Sem_Ch8; use Sem_Ch8;
54 with Sem_Ch10; use Sem_Ch10;
55 with Sem_Dist; use Sem_Dist;
56 with Sem_Elim; use Sem_Elim;
57 with Sem_Eval; use Sem_Eval;
58 with Sem_Res; use Sem_Res;
59 with Sem_Type; use Sem_Type;
60 with Sem_Util; use Sem_Util;
61 with Stand; use Stand;
62 with Sinfo; use Sinfo;
63 with Sinput; use Sinput;
64 with Stringt; use Stringt;
66 with Stylesw; use Stylesw;
67 with Targparm; use Targparm;
68 with Ttypes; use Ttypes;
69 with Tbuild; use Tbuild;
70 with Uintp; use Uintp;
71 with Urealp; use Urealp;
73 package body Sem_Attr is
75 True_Value : constant Uint := Uint_1;
76 False_Value : constant Uint := Uint_0;
77 -- Synonyms to be used when these constants are used as Boolean values
79 Bad_Attribute : exception;
80 -- Exception raised if an error is detected during attribute processing,
81 -- used so that we can abandon the processing so we don't run into
82 -- trouble with cascaded errors.
84 -- The following array is the list of attributes defined in the Ada 83 RM
85 -- that are not included in Ada 95, but still get recognized in GNAT.
87 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
93 Attribute_Constrained |
100 Attribute_First_Bit |
106 Attribute_Leading_Part |
108 Attribute_Machine_Emax |
109 Attribute_Machine_Emin |
110 Attribute_Machine_Mantissa |
111 Attribute_Machine_Overflows |
112 Attribute_Machine_Radix |
113 Attribute_Machine_Rounds |
119 Attribute_Safe_Emax |
120 Attribute_Safe_Large |
121 Attribute_Safe_Small |
124 Attribute_Storage_Size |
126 Attribute_Terminated |
129 Attribute_Width => True,
132 -- The following array is the list of attributes defined in the Ada 2005
133 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
134 -- but in Ada 95 they are considered to be implementation defined.
136 Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'(
137 Attribute_Machine_Rounding |
140 Attribute_Stream_Size |
141 Attribute_Wide_Wide_Width => True,
144 -- The following array contains all attributes that imply a modification
145 -- of their prefixes or result in an access value. Such prefixes can be
146 -- considered as lvalues.
148 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
149 Attribute_Class_Array'(
154 Attribute_Unchecked_Access |
155 Attribute_Unrestricted_Access => True,
158 -----------------------
159 -- Local_Subprograms --
160 -----------------------
162 procedure Eval_Attribute (N : Node_Id);
163 -- Performs compile time evaluation of attributes where possible, leaving
164 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
165 -- set, and replacing the node with a literal node if the value can be
166 -- computed at compile time. All static attribute references are folded,
167 -- as well as a number of cases of non-static attributes that can always
168 -- be computed at compile time (e.g. floating-point model attributes that
169 -- are applied to non-static subtypes). Of course in such cases, the
170 -- Is_Static_Expression flag will not be set on the resulting literal.
171 -- Note that the only required action of this procedure is to catch the
172 -- static expression cases as described in the RM. Folding of other cases
173 -- is done where convenient, but some additional non-static folding is in
174 -- N_Expand_Attribute_Reference in cases where this is more convenient.
176 function Is_Anonymous_Tagged_Base
180 -- For derived tagged types that constrain parent discriminants we build
181 -- an anonymous unconstrained base type. We need to recognize the relation
182 -- between the two when analyzing an access attribute for a constrained
183 -- component, before the full declaration for Typ has been analyzed, and
184 -- where therefore the prefix of the attribute does not match the enclosing
187 -----------------------
188 -- Analyze_Attribute --
189 -----------------------
191 procedure Analyze_Attribute (N : Node_Id) is
192 Loc : constant Source_Ptr := Sloc (N);
193 Aname : constant Name_Id := Attribute_Name (N);
194 P : constant Node_Id := Prefix (N);
195 Exprs : constant List_Id := Expressions (N);
196 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
201 -- Type of prefix after analysis
203 P_Base_Type : Entity_Id;
204 -- Base type of prefix after analysis
206 -----------------------
207 -- Local Subprograms --
208 -----------------------
210 procedure Analyze_Access_Attribute;
211 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
212 -- Internally, Id distinguishes which of the three cases is involved.
214 procedure Bad_Attribute_For_Predicate;
215 -- Output error message for use of a predicate (First, Last, Range) not
216 -- allowed with a type that has predicates. If the type is a generic
217 -- actual, then the message is a warning, and we generate code to raise
218 -- program error with an appropriate reason. No error message is given
219 -- for internally generated uses of the attributes.
221 procedure Check_Array_Or_Scalar_Type;
222 -- Common procedure used by First, Last, Range attribute to check
223 -- that the prefix is a constrained array or scalar type, or a name
224 -- of an array object, and that an argument appears only if appropriate
225 -- (i.e. only in the array case).
227 procedure Check_Array_Type;
228 -- Common semantic checks for all array attributes. Checks that the
229 -- prefix is a constrained array type or the name of an array object.
230 -- The error message for non-arrays is specialized appropriately.
232 procedure Check_Asm_Attribute;
233 -- Common semantic checks for Asm_Input and Asm_Output attributes
235 procedure Check_Component;
236 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
237 -- Position. Checks prefix is an appropriate selected component.
239 procedure Check_Decimal_Fixed_Point_Type;
240 -- Check that prefix of attribute N is a decimal fixed-point type
242 procedure Check_Dereference;
243 -- If the prefix of attribute is an object of an access type, then
244 -- introduce an explicit dereference, and adjust P_Type accordingly.
246 procedure Check_Discrete_Type;
247 -- Verify that prefix of attribute N is a discrete type
250 -- Check that no attribute arguments are present
252 procedure Check_Either_E0_Or_E1;
253 -- Check that there are zero or one attribute arguments present
256 -- Check that exactly one attribute argument is present
259 -- Check that two attribute arguments are present
261 procedure Check_Enum_Image;
262 -- If the prefix type is an enumeration type, set all its literals
263 -- as referenced, since the image function could possibly end up
264 -- referencing any of the literals indirectly. Same for Enum_Val.
266 procedure Check_Fixed_Point_Type;
267 -- Verify that prefix of attribute N is a fixed type
269 procedure Check_Fixed_Point_Type_0;
270 -- Verify that prefix of attribute N is a fixed type and that
271 -- no attribute expressions are present
273 procedure Check_Floating_Point_Type;
274 -- Verify that prefix of attribute N is a float type
276 procedure Check_Floating_Point_Type_0;
277 -- Verify that prefix of attribute N is a float type and that
278 -- no attribute expressions are present
280 procedure Check_Floating_Point_Type_1;
281 -- Verify that prefix of attribute N is a float type and that
282 -- exactly one attribute expression is present
284 procedure Check_Floating_Point_Type_2;
285 -- Verify that prefix of attribute N is a float type and that
286 -- two attribute expressions are present
288 procedure Legal_Formal_Attribute;
289 -- Common processing for attributes Definite and Has_Discriminants.
290 -- Checks that prefix is generic indefinite formal type.
292 procedure Check_Formal_Restriction_On_Attribute;
293 -- Issue an error in formal mode because attribute N is allowed
295 procedure Check_Integer_Type;
296 -- Verify that prefix of attribute N is an integer type
298 procedure Check_Library_Unit;
299 -- Verify that prefix of attribute N is a library unit
301 procedure Check_Modular_Integer_Type;
302 -- Verify that prefix of attribute N is a modular integer type
304 procedure Check_Not_CPP_Type;
305 -- Check that P (the prefix of the attribute) is not an CPP type
306 -- for which no Ada predefined primitive is available.
308 procedure Check_Not_Incomplete_Type;
309 -- Check that P (the prefix of the attribute) is not an incomplete
310 -- type or a private type for which no full view has been given.
312 procedure Check_Object_Reference (P : Node_Id);
313 -- Check that P (the prefix of the attribute) is an object reference
315 procedure Check_Program_Unit;
316 -- Verify that prefix of attribute N is a program unit
318 procedure Check_Real_Type;
319 -- Verify that prefix of attribute N is fixed or float type
321 procedure Check_Scalar_Type;
322 -- Verify that prefix of attribute N is a scalar type
324 procedure Check_Standard_Prefix;
325 -- Verify that prefix of attribute N is package Standard
327 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
328 -- Validity checking for stream attribute. Nam is the TSS name of the
329 -- corresponding possible defined attribute function (e.g. for the
330 -- Read attribute, Nam will be TSS_Stream_Read).
332 procedure Check_PolyORB_Attribute;
333 -- Validity checking for PolyORB/DSA attribute
335 procedure Check_Task_Prefix;
336 -- Verify that prefix of attribute N is a task or task type
338 procedure Check_Type;
339 -- Verify that the prefix of attribute N is a type
341 procedure Check_Unit_Name (Nod : Node_Id);
342 -- Check that Nod is of the form of a library unit name, i.e that
343 -- it is an identifier, or a selected component whose prefix is
344 -- itself of the form of a library unit name. Note that this is
345 -- quite different from Check_Program_Unit, since it only checks
346 -- the syntactic form of the name, not the semantic identity. This
347 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
348 -- UET_Address) which can refer to non-visible unit.
350 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
351 pragma No_Return (Error_Attr);
352 procedure Error_Attr;
353 pragma No_Return (Error_Attr);
354 -- Posts error using Error_Msg_N at given node, sets type of attribute
355 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
356 -- semantic processing. The message typically contains a % insertion
357 -- character which is replaced by the attribute name. The call with
358 -- no arguments is used when the caller has already generated the
359 -- required error messages.
361 procedure Error_Attr_P (Msg : String);
362 pragma No_Return (Error_Attr);
363 -- Like Error_Attr, but error is posted at the start of the prefix
365 procedure Standard_Attribute (Val : Int);
366 -- Used to process attributes whose prefix is package Standard which
367 -- yield values of type Universal_Integer. The attribute reference
368 -- node is rewritten with an integer literal of the given value.
370 procedure Unexpected_Argument (En : Node_Id);
371 -- Signal unexpected attribute argument (En is the argument)
373 procedure Validate_Non_Static_Attribute_Function_Call;
374 -- Called when processing an attribute that is a function call to a
375 -- non-static function, i.e. an attribute function that either takes
376 -- non-scalar arguments or returns a non-scalar result. Verifies that
377 -- such a call does not appear in a preelaborable context.
379 ------------------------------
380 -- Analyze_Access_Attribute --
381 ------------------------------
383 procedure Analyze_Access_Attribute is
384 Acc_Type : Entity_Id;
389 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
390 -- Build an access-to-object type whose designated type is DT,
391 -- and whose Ekind is appropriate to the attribute type. The
392 -- type that is constructed is returned as the result.
394 procedure Build_Access_Subprogram_Type (P : Node_Id);
395 -- Build an access to subprogram whose designated type is the type of
396 -- the prefix. If prefix is overloaded, so is the node itself. The
397 -- result is stored in Acc_Type.
399 function OK_Self_Reference return Boolean;
400 -- An access reference whose prefix is a type can legally appear
401 -- within an aggregate, where it is obtained by expansion of
402 -- a defaulted aggregate. The enclosing aggregate that contains
403 -- the self-referenced is flagged so that the self-reference can
404 -- be expanded into a reference to the target object (see exp_aggr).
406 ------------------------------
407 -- Build_Access_Object_Type --
408 ------------------------------
410 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
411 Typ : constant Entity_Id :=
413 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
415 Set_Etype (Typ, Typ);
417 Set_Associated_Node_For_Itype (Typ, N);
418 Set_Directly_Designated_Type (Typ, DT);
420 end Build_Access_Object_Type;
422 ----------------------------------
423 -- Build_Access_Subprogram_Type --
424 ----------------------------------
426 procedure Build_Access_Subprogram_Type (P : Node_Id) is
427 Index : Interp_Index;
430 procedure Check_Local_Access (E : Entity_Id);
431 -- Deal with possible access to local subprogram. If we have such
432 -- an access, we set a flag to kill all tracked values on any call
433 -- because this access value may be passed around, and any called
434 -- code might use it to access a local procedure which clobbers a
435 -- tracked value. If the scope is a loop or block, indicate that
436 -- value tracking is disabled for the enclosing subprogram.
438 function Get_Kind (E : Entity_Id) return Entity_Kind;
439 -- Distinguish between access to regular/protected subprograms
441 ------------------------
442 -- Check_Local_Access --
443 ------------------------
445 procedure Check_Local_Access (E : Entity_Id) is
447 if not Is_Library_Level_Entity (E) then
448 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
449 Set_Suppress_Value_Tracking_On_Call
450 (Nearest_Dynamic_Scope (Current_Scope));
452 end Check_Local_Access;
458 function Get_Kind (E : Entity_Id) return Entity_Kind is
460 if Convention (E) = Convention_Protected then
461 return E_Access_Protected_Subprogram_Type;
463 return E_Access_Subprogram_Type;
467 -- Start of processing for Build_Access_Subprogram_Type
470 -- In the case of an access to subprogram, use the name of the
471 -- subprogram itself as the designated type. Type-checking in
472 -- this case compares the signatures of the designated types.
474 -- Note: This fragment of the tree is temporarily malformed
475 -- because the correct tree requires an E_Subprogram_Type entity
476 -- as the designated type. In most cases this designated type is
477 -- later overridden by the semantics with the type imposed by the
478 -- context during the resolution phase. In the specific case of
479 -- the expression Address!(Prim'Unrestricted_Access), used to
480 -- initialize slots of dispatch tables, this work will be done by
481 -- the expander (see Exp_Aggr).
483 -- The reason to temporarily add this kind of node to the tree
484 -- instead of a proper E_Subprogram_Type itype, is the following:
485 -- in case of errors found in the source file we report better
486 -- error messages. For example, instead of generating the
489 -- "expected access to subprogram with profile
490 -- defined at line X"
492 -- we currently generate:
494 -- "expected access to function Z defined at line X"
496 Set_Etype (N, Any_Type);
498 if not Is_Overloaded (P) then
499 Check_Local_Access (Entity (P));
501 if not Is_Intrinsic_Subprogram (Entity (P)) then
502 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
503 Set_Is_Public (Acc_Type, False);
504 Set_Etype (Acc_Type, Acc_Type);
505 Set_Convention (Acc_Type, Convention (Entity (P)));
506 Set_Directly_Designated_Type (Acc_Type, Entity (P));
507 Set_Etype (N, Acc_Type);
508 Freeze_Before (N, Acc_Type);
512 Get_First_Interp (P, Index, It);
513 while Present (It.Nam) loop
514 Check_Local_Access (It.Nam);
516 if not Is_Intrinsic_Subprogram (It.Nam) then
517 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
518 Set_Is_Public (Acc_Type, False);
519 Set_Etype (Acc_Type, Acc_Type);
520 Set_Convention (Acc_Type, Convention (It.Nam));
521 Set_Directly_Designated_Type (Acc_Type, It.Nam);
522 Add_One_Interp (N, Acc_Type, Acc_Type);
523 Freeze_Before (N, Acc_Type);
526 Get_Next_Interp (Index, It);
530 -- Cannot be applied to intrinsic. Looking at the tests above,
531 -- the only way Etype (N) can still be set to Any_Type is if
532 -- Is_Intrinsic_Subprogram was True for some referenced entity.
534 if Etype (N) = Any_Type then
535 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
537 end Build_Access_Subprogram_Type;
539 ----------------------
540 -- OK_Self_Reference --
541 ----------------------
543 function OK_Self_Reference return Boolean is
550 (Nkind (Par) = N_Component_Association
551 or else Nkind (Par) in N_Subexpr)
553 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
554 if Etype (Par) = Typ then
555 Set_Has_Self_Reference (Par);
563 -- No enclosing aggregate, or not a self-reference
566 end OK_Self_Reference;
568 -- Start of processing for Analyze_Access_Attribute
571 Check_Formal_Restriction_On_Attribute;
574 if Nkind (P) = N_Character_Literal then
576 ("prefix of % attribute cannot be enumeration literal");
579 -- Case of access to subprogram
581 if Is_Entity_Name (P)
582 and then Is_Overloadable (Entity (P))
584 if Has_Pragma_Inline_Always (Entity (P)) then
586 ("prefix of % attribute cannot be Inline_Always subprogram");
589 if Aname = Name_Unchecked_Access then
590 Error_Attr ("attribute% cannot be applied to a subprogram", P);
593 -- Issue an error if the prefix denotes an eliminated subprogram
595 Check_For_Eliminated_Subprogram (P, Entity (P));
597 -- Check for obsolescent subprogram reference
599 Check_Obsolescent_2005_Entity (Entity (P), P);
601 -- Build the appropriate subprogram type
603 Build_Access_Subprogram_Type (P);
605 -- For unrestricted access, kill current values, since this
606 -- attribute allows a reference to a local subprogram that
607 -- could modify local variables to be passed out of scope
609 if Aname = Name_Unrestricted_Access then
611 -- Do not kill values on nodes initializing dispatch tables
612 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
613 -- is currently generated by the expander only for this
614 -- purpose. Done to keep the quality of warnings currently
615 -- generated by the compiler (otherwise any declaration of
616 -- a tagged type cleans constant indications from its scope).
618 if Nkind (Parent (N)) = N_Unchecked_Type_Conversion
619 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
621 Etype (Parent (N)) = RTE (RE_Size_Ptr))
622 and then Is_Dispatching_Operation
623 (Directly_Designated_Type (Etype (N)))
633 -- Component is an operation of a protected type
635 elsif Nkind (P) = N_Selected_Component
636 and then Is_Overloadable (Entity (Selector_Name (P)))
638 if Ekind (Entity (Selector_Name (P))) = E_Entry then
639 Error_Attr_P ("prefix of % attribute must be subprogram");
642 Build_Access_Subprogram_Type (Selector_Name (P));
646 -- Deal with incorrect reference to a type, but note that some
647 -- accesses are allowed: references to the current type instance,
648 -- or in Ada 2005 self-referential pointer in a default-initialized
651 if Is_Entity_Name (P) then
654 -- The reference may appear in an aggregate that has been expanded
655 -- into a loop. Locate scope of type definition, if any.
657 Scop := Current_Scope;
658 while Ekind (Scop) = E_Loop loop
659 Scop := Scope (Scop);
662 if Is_Type (Typ) then
664 -- OK if we are within the scope of a limited type
665 -- let's mark the component as having per object constraint
667 if Is_Anonymous_Tagged_Base (Scop, Typ) then
675 Q : Node_Id := Parent (N);
679 and then Nkind (Q) /= N_Component_Declaration
685 Set_Has_Per_Object_Constraint
686 (Defining_Identifier (Q), True);
690 if Nkind (P) = N_Expanded_Name then
692 ("current instance prefix must be a direct name", P);
695 -- If a current instance attribute appears in a component
696 -- constraint it must appear alone; other contexts (spec-
697 -- expressions, within a task body) are not subject to this
700 if not In_Spec_Expression
701 and then not Has_Completion (Scop)
703 Nkind_In (Parent (N), N_Discriminant_Association,
704 N_Index_Or_Discriminant_Constraint)
707 ("current instance attribute must appear alone", N);
710 if Is_CPP_Class (Root_Type (Typ)) then
712 ("?current instance unsupported for derivations of "
713 & "'C'P'P types", N);
716 -- OK if we are in initialization procedure for the type
717 -- in question, in which case the reference to the type
718 -- is rewritten as a reference to the current object.
720 elsif Ekind (Scop) = E_Procedure
721 and then Is_Init_Proc (Scop)
722 and then Etype (First_Formal (Scop)) = Typ
725 Make_Attribute_Reference (Loc,
726 Prefix => Make_Identifier (Loc, Name_uInit),
727 Attribute_Name => Name_Unrestricted_Access));
731 -- OK if a task type, this test needs sharpening up ???
733 elsif Is_Task_Type (Typ) then
736 -- OK if self-reference in an aggregate in Ada 2005, and
737 -- the reference comes from a copied default expression.
739 -- Note that we check legality of self-reference even if the
740 -- expression comes from source, e.g. when a single component
741 -- association in an aggregate has a box association.
743 elsif Ada_Version >= Ada_2005
744 and then OK_Self_Reference
748 -- OK if reference to current instance of a protected object
750 elsif Is_Protected_Self_Reference (P) then
753 -- Otherwise we have an error case
756 Error_Attr ("% attribute cannot be applied to type", P);
762 -- If we fall through, we have a normal access to object case.
763 -- Unrestricted_Access is legal wherever an allocator would be
764 -- legal, so its Etype is set to E_Allocator. The expected type
765 -- of the other attributes is a general access type, and therefore
766 -- we label them with E_Access_Attribute_Type.
768 if not Is_Overloaded (P) then
769 Acc_Type := Build_Access_Object_Type (P_Type);
770 Set_Etype (N, Acc_Type);
773 Index : Interp_Index;
776 Set_Etype (N, Any_Type);
777 Get_First_Interp (P, Index, It);
778 while Present (It.Typ) loop
779 Acc_Type := Build_Access_Object_Type (It.Typ);
780 Add_One_Interp (N, Acc_Type, Acc_Type);
781 Get_Next_Interp (Index, It);
786 -- Special cases when we can find a prefix that is an entity name
795 if Is_Entity_Name (PP) then
798 -- If we have an access to an object, and the attribute
799 -- comes from source, then set the object as potentially
800 -- source modified. We do this because the resulting access
801 -- pointer can be used to modify the variable, and we might
802 -- not detect this, leading to some junk warnings.
804 Set_Never_Set_In_Source (Ent, False);
806 -- Mark entity as address taken, and kill current values
808 Set_Address_Taken (Ent);
809 Kill_Current_Values (Ent);
812 elsif Nkind_In (PP, N_Selected_Component,
823 -- Check for aliased view unless unrestricted case. We allow a
824 -- nonaliased prefix when within an instance because the prefix may
825 -- have been a tagged formal object, which is defined to be aliased
826 -- even when the actual might not be (other instance cases will have
827 -- been caught in the generic). Similarly, within an inlined body we
828 -- know that the attribute is legal in the original subprogram, and
829 -- therefore legal in the expansion.
831 if Aname /= Name_Unrestricted_Access
832 and then not Is_Aliased_View (P)
833 and then not In_Instance
834 and then not In_Inlined_Body
836 Error_Attr_P ("prefix of % attribute must be aliased");
838 end Analyze_Access_Attribute;
840 ---------------------------------
841 -- Bad_Attribute_For_Predicate --
842 ---------------------------------
844 procedure Bad_Attribute_For_Predicate is
846 if Comes_From_Source (N) then
847 Error_Msg_Name_1 := Aname;
848 Bad_Predicated_Subtype_Use
849 ("type& has predicates, attribute % not allowed", N, P_Type);
851 end Bad_Attribute_For_Predicate;
853 --------------------------------
854 -- Check_Array_Or_Scalar_Type --
855 --------------------------------
857 procedure Check_Array_Or_Scalar_Type is
861 -- Dimension number for array attributes
864 -- Case of string literal or string literal subtype. These cases
865 -- cannot arise from legal Ada code, but the expander is allowed
866 -- to generate them. They require special handling because string
867 -- literal subtypes do not have standard bounds (the whole idea
868 -- of these subtypes is to avoid having to generate the bounds)
870 if Ekind (P_Type) = E_String_Literal_Subtype then
871 Set_Etype (N, Etype (First_Index (P_Base_Type)));
876 elsif Is_Scalar_Type (P_Type) then
880 Error_Attr ("invalid argument in % attribute", E1);
882 Set_Etype (N, P_Base_Type);
886 -- The following is a special test to allow 'First to apply to
887 -- private scalar types if the attribute comes from generated
888 -- code. This occurs in the case of Normalize_Scalars code.
890 elsif Is_Private_Type (P_Type)
891 and then Present (Full_View (P_Type))
892 and then Is_Scalar_Type (Full_View (P_Type))
893 and then not Comes_From_Source (N)
895 Set_Etype (N, Implementation_Base_Type (P_Type));
897 -- Array types other than string literal subtypes handled above
902 -- We know prefix is an array type, or the name of an array
903 -- object, and that the expression, if present, is static
904 -- and within the range of the dimensions of the type.
906 pragma Assert (Is_Array_Type (P_Type));
907 Index := First_Index (P_Base_Type);
911 -- First dimension assumed
913 Set_Etype (N, Base_Type (Etype (Index)));
916 D := UI_To_Int (Intval (E1));
918 for J in 1 .. D - 1 loop
922 Set_Etype (N, Base_Type (Etype (Index)));
923 Set_Etype (E1, Standard_Integer);
926 end Check_Array_Or_Scalar_Type;
928 ----------------------
929 -- Check_Array_Type --
930 ----------------------
932 procedure Check_Array_Type is
934 -- Dimension number for array attributes
937 -- If the type is a string literal type, then this must be generated
938 -- internally, and no further check is required on its legality.
940 if Ekind (P_Type) = E_String_Literal_Subtype then
943 -- If the type is a composite, it is an illegal aggregate, no point
946 elsif P_Type = Any_Composite then
950 -- Normal case of array type or subtype
952 Check_Either_E0_Or_E1;
955 if Is_Array_Type (P_Type) then
956 if not Is_Constrained (P_Type)
957 and then Is_Entity_Name (P)
958 and then Is_Type (Entity (P))
960 -- Note: we do not call Error_Attr here, since we prefer to
961 -- continue, using the relevant index type of the array,
962 -- even though it is unconstrained. This gives better error
963 -- recovery behavior.
965 Error_Msg_Name_1 := Aname;
967 ("prefix for % attribute must be constrained array", P);
970 D := Number_Dimensions (P_Type);
973 if Is_Private_Type (P_Type) then
974 Error_Attr_P ("prefix for % attribute may not be private type");
976 elsif Is_Access_Type (P_Type)
977 and then Is_Array_Type (Designated_Type (P_Type))
978 and then Is_Entity_Name (P)
979 and then Is_Type (Entity (P))
981 Error_Attr_P ("prefix of % attribute cannot be access type");
983 elsif Attr_Id = Attribute_First
985 Attr_Id = Attribute_Last
987 Error_Attr ("invalid prefix for % attribute", P);
990 Error_Attr_P ("prefix for % attribute must be array");
995 Resolve (E1, Any_Integer);
996 Set_Etype (E1, Standard_Integer);
998 if not Is_Static_Expression (E1)
999 or else Raises_Constraint_Error (E1)
1001 Flag_Non_Static_Expr
1002 ("expression for dimension must be static!", E1);
1005 elsif UI_To_Int (Expr_Value (E1)) > D
1006 or else UI_To_Int (Expr_Value (E1)) < 1
1008 Error_Attr ("invalid dimension number for array type", E1);
1012 if (Style_Check and Style_Check_Array_Attribute_Index)
1013 and then Comes_From_Source (N)
1015 Style.Check_Array_Attribute_Index (N, E1, D);
1017 end Check_Array_Type;
1019 -------------------------
1020 -- Check_Asm_Attribute --
1021 -------------------------
1023 procedure Check_Asm_Attribute is
1028 -- Check first argument is static string expression
1030 Analyze_And_Resolve (E1, Standard_String);
1032 if Etype (E1) = Any_Type then
1035 elsif not Is_OK_Static_Expression (E1) then
1036 Flag_Non_Static_Expr
1037 ("constraint argument must be static string expression!", E1);
1041 -- Check second argument is right type
1043 Analyze_And_Resolve (E2, Entity (P));
1045 -- Note: that is all we need to do, we don't need to check
1046 -- that it appears in a correct context. The Ada type system
1047 -- will do that for us.
1049 end Check_Asm_Attribute;
1051 ---------------------
1052 -- Check_Component --
1053 ---------------------
1055 procedure Check_Component is
1059 if Nkind (P) /= N_Selected_Component
1061 (Ekind (Entity (Selector_Name (P))) /= E_Component
1063 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1065 Error_Attr_P ("prefix for % attribute must be selected component");
1067 end Check_Component;
1069 ------------------------------------
1070 -- Check_Decimal_Fixed_Point_Type --
1071 ------------------------------------
1073 procedure Check_Decimal_Fixed_Point_Type is
1077 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1078 Error_Attr_P ("prefix of % attribute must be decimal type");
1080 end Check_Decimal_Fixed_Point_Type;
1082 -----------------------
1083 -- Check_Dereference --
1084 -----------------------
1086 procedure Check_Dereference is
1089 -- Case of a subtype mark
1091 if Is_Entity_Name (P)
1092 and then Is_Type (Entity (P))
1097 -- Case of an expression
1101 if Is_Access_Type (P_Type) then
1103 -- If there is an implicit dereference, then we must freeze
1104 -- the designated type of the access type, since the type of
1105 -- the referenced array is this type (see AI95-00106).
1107 -- As done elsewhere, freezing must not happen when pre-analyzing
1108 -- a pre- or postcondition or a default value for an object or
1109 -- for a formal parameter.
1111 if not In_Spec_Expression then
1112 Freeze_Before (N, Designated_Type (P_Type));
1116 Make_Explicit_Dereference (Sloc (P),
1117 Prefix => Relocate_Node (P)));
1119 Analyze_And_Resolve (P);
1120 P_Type := Etype (P);
1122 if P_Type = Any_Type then
1123 raise Bad_Attribute;
1126 P_Base_Type := Base_Type (P_Type);
1128 end Check_Dereference;
1130 -------------------------
1131 -- Check_Discrete_Type --
1132 -------------------------
1134 procedure Check_Discrete_Type is
1138 if not Is_Discrete_Type (P_Type) then
1139 Error_Attr_P ("prefix of % attribute must be discrete type");
1141 end Check_Discrete_Type;
1147 procedure Check_E0 is
1149 if Present (E1) then
1150 Unexpected_Argument (E1);
1158 procedure Check_E1 is
1160 Check_Either_E0_Or_E1;
1164 -- Special-case attributes that are functions and that appear as
1165 -- the prefix of another attribute. Error is posted on parent.
1167 if Nkind (Parent (N)) = N_Attribute_Reference
1168 and then (Attribute_Name (Parent (N)) = Name_Address
1170 Attribute_Name (Parent (N)) = Name_Code_Address
1172 Attribute_Name (Parent (N)) = Name_Access)
1174 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1175 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1176 Set_Etype (Parent (N), Any_Type);
1177 Set_Entity (Parent (N), Any_Type);
1178 raise Bad_Attribute;
1181 Error_Attr ("missing argument for % attribute", N);
1190 procedure Check_E2 is
1193 Error_Attr ("missing arguments for % attribute (2 required)", N);
1195 Error_Attr ("missing argument for % attribute (2 required)", N);
1199 ---------------------------
1200 -- Check_Either_E0_Or_E1 --
1201 ---------------------------
1203 procedure Check_Either_E0_Or_E1 is
1205 if Present (E2) then
1206 Unexpected_Argument (E2);
1208 end Check_Either_E0_Or_E1;
1210 ----------------------
1211 -- Check_Enum_Image --
1212 ----------------------
1214 procedure Check_Enum_Image is
1217 if Is_Enumeration_Type (P_Base_Type) then
1218 Lit := First_Literal (P_Base_Type);
1219 while Present (Lit) loop
1220 Set_Referenced (Lit);
1224 end Check_Enum_Image;
1226 ----------------------------
1227 -- Check_Fixed_Point_Type --
1228 ----------------------------
1230 procedure Check_Fixed_Point_Type is
1234 if not Is_Fixed_Point_Type (P_Type) then
1235 Error_Attr_P ("prefix of % attribute must be fixed point type");
1237 end Check_Fixed_Point_Type;
1239 ------------------------------
1240 -- Check_Fixed_Point_Type_0 --
1241 ------------------------------
1243 procedure Check_Fixed_Point_Type_0 is
1245 Check_Fixed_Point_Type;
1247 end Check_Fixed_Point_Type_0;
1249 -------------------------------
1250 -- Check_Floating_Point_Type --
1251 -------------------------------
1253 procedure Check_Floating_Point_Type is
1257 if not Is_Floating_Point_Type (P_Type) then
1258 Error_Attr_P ("prefix of % attribute must be float type");
1260 end Check_Floating_Point_Type;
1262 ---------------------------------
1263 -- Check_Floating_Point_Type_0 --
1264 ---------------------------------
1266 procedure Check_Floating_Point_Type_0 is
1268 Check_Floating_Point_Type;
1270 end Check_Floating_Point_Type_0;
1272 ---------------------------------
1273 -- Check_Floating_Point_Type_1 --
1274 ---------------------------------
1276 procedure Check_Floating_Point_Type_1 is
1278 Check_Floating_Point_Type;
1280 end Check_Floating_Point_Type_1;
1282 ---------------------------------
1283 -- Check_Floating_Point_Type_2 --
1284 ---------------------------------
1286 procedure Check_Floating_Point_Type_2 is
1288 Check_Floating_Point_Type;
1290 end Check_Floating_Point_Type_2;
1292 -------------------------------------------
1293 -- Check_Formal_Restriction_On_Attribute --
1294 -------------------------------------------
1296 procedure Check_Formal_Restriction_On_Attribute is
1298 Error_Msg_Name_1 := Aname;
1299 Check_Formal_Restriction ("attribute % is not allowed", P);
1300 end Check_Formal_Restriction_On_Attribute;
1302 ------------------------
1303 -- Check_Integer_Type --
1304 ------------------------
1306 procedure Check_Integer_Type is
1310 if not Is_Integer_Type (P_Type) then
1311 Error_Attr_P ("prefix of % attribute must be integer type");
1313 end Check_Integer_Type;
1315 ------------------------
1316 -- Check_Library_Unit --
1317 ------------------------
1319 procedure Check_Library_Unit is
1321 if not Is_Compilation_Unit (Entity (P)) then
1322 Error_Attr_P ("prefix of % attribute must be library unit");
1324 end Check_Library_Unit;
1326 --------------------------------
1327 -- Check_Modular_Integer_Type --
1328 --------------------------------
1330 procedure Check_Modular_Integer_Type is
1334 if not Is_Modular_Integer_Type (P_Type) then
1336 ("prefix of % attribute must be modular integer type");
1338 end Check_Modular_Integer_Type;
1340 ------------------------
1341 -- Check_Not_CPP_Type --
1342 ------------------------
1344 procedure Check_Not_CPP_Type is
1346 if Is_Tagged_Type (Etype (P))
1347 and then Convention (Etype (P)) = Convention_CPP
1348 and then Is_CPP_Class (Root_Type (Etype (P)))
1351 ("invalid use of % attribute with 'C'P'P tagged type");
1353 end Check_Not_CPP_Type;
1355 -------------------------------
1356 -- Check_Not_Incomplete_Type --
1357 -------------------------------
1359 procedure Check_Not_Incomplete_Type is
1364 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1365 -- dereference we have to check wrong uses of incomplete types
1366 -- (other wrong uses are checked at their freezing point).
1368 -- Example 1: Limited-with
1370 -- limited with Pkg;
1372 -- type Acc is access Pkg.T;
1374 -- S : Integer := X.all'Size; -- ERROR
1377 -- Example 2: Tagged incomplete
1379 -- type T is tagged;
1380 -- type Acc is access all T;
1382 -- S : constant Integer := X.all'Size; -- ERROR
1383 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1385 if Ada_Version >= Ada_2005
1386 and then Nkind (P) = N_Explicit_Dereference
1389 while Nkind (E) = N_Explicit_Dereference loop
1395 if From_With_Type (Typ) then
1397 ("prefix of % attribute cannot be an incomplete type");
1400 if Is_Access_Type (Typ) then
1401 Typ := Directly_Designated_Type (Typ);
1404 if Is_Class_Wide_Type (Typ) then
1405 Typ := Root_Type (Typ);
1408 -- A legal use of a shadow entity occurs only when the unit
1409 -- where the non-limited view resides is imported via a regular
1410 -- with clause in the current body. Such references to shadow
1411 -- entities may occur in subprogram formals.
1413 if Is_Incomplete_Type (Typ)
1414 and then From_With_Type (Typ)
1415 and then Present (Non_Limited_View (Typ))
1416 and then Is_Legal_Shadow_Entity_In_Body (Typ)
1418 Typ := Non_Limited_View (Typ);
1421 if Ekind (Typ) = E_Incomplete_Type
1422 and then No (Full_View (Typ))
1425 ("prefix of % attribute cannot be an incomplete type");
1430 if not Is_Entity_Name (P)
1431 or else not Is_Type (Entity (P))
1432 or else In_Spec_Expression
1436 Check_Fully_Declared (P_Type, P);
1438 end Check_Not_Incomplete_Type;
1440 ----------------------------
1441 -- Check_Object_Reference --
1442 ----------------------------
1444 procedure Check_Object_Reference (P : Node_Id) is
1448 -- If we need an object, and we have a prefix that is the name of
1449 -- a function entity, convert it into a function call.
1451 if Is_Entity_Name (P)
1452 and then Ekind (Entity (P)) = E_Function
1454 Rtyp := Etype (Entity (P));
1457 Make_Function_Call (Sloc (P),
1458 Name => Relocate_Node (P)));
1460 Analyze_And_Resolve (P, Rtyp);
1462 -- Otherwise we must have an object reference
1464 elsif not Is_Object_Reference (P) then
1465 Error_Attr_P ("prefix of % attribute must be object");
1467 end Check_Object_Reference;
1469 ----------------------------
1470 -- Check_PolyORB_Attribute --
1471 ----------------------------
1473 procedure Check_PolyORB_Attribute is
1475 Validate_Non_Static_Attribute_Function_Call;
1480 if Get_PCS_Name /= Name_PolyORB_DSA then
1482 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
1484 end Check_PolyORB_Attribute;
1486 ------------------------
1487 -- Check_Program_Unit --
1488 ------------------------
1490 procedure Check_Program_Unit is
1492 if Is_Entity_Name (P) then
1494 K : constant Entity_Kind := Ekind (Entity (P));
1495 T : constant Entity_Id := Etype (Entity (P));
1498 if K in Subprogram_Kind
1499 or else K in Task_Kind
1500 or else K in Protected_Kind
1501 or else K = E_Package
1502 or else K in Generic_Unit_Kind
1503 or else (K = E_Variable
1507 Is_Protected_Type (T)))
1514 Error_Attr_P ("prefix of % attribute must be program unit");
1515 end Check_Program_Unit;
1517 ---------------------
1518 -- Check_Real_Type --
1519 ---------------------
1521 procedure Check_Real_Type is
1525 if not Is_Real_Type (P_Type) then
1526 Error_Attr_P ("prefix of % attribute must be real type");
1528 end Check_Real_Type;
1530 -----------------------
1531 -- Check_Scalar_Type --
1532 -----------------------
1534 procedure Check_Scalar_Type is
1538 if not Is_Scalar_Type (P_Type) then
1539 Error_Attr_P ("prefix of % attribute must be scalar type");
1541 end Check_Scalar_Type;
1543 ---------------------------
1544 -- Check_Standard_Prefix --
1545 ---------------------------
1547 procedure Check_Standard_Prefix is
1551 if Nkind (P) /= N_Identifier
1552 or else Chars (P) /= Name_Standard
1554 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1556 end Check_Standard_Prefix;
1558 ----------------------------
1559 -- Check_Stream_Attribute --
1560 ----------------------------
1562 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1566 In_Shared_Var_Procs : Boolean;
1567 -- True when compiling the body of System.Shared_Storage.
1568 -- Shared_Var_Procs. For this runtime package (always compiled in
1569 -- GNAT mode), we allow stream attributes references for limited
1570 -- types for the case where shared passive objects are implemented
1571 -- using stream attributes, which is the default in GNAT's persistent
1572 -- storage implementation.
1575 Validate_Non_Static_Attribute_Function_Call;
1577 -- With the exception of 'Input, Stream attributes are procedures,
1578 -- and can only appear at the position of procedure calls. We check
1579 -- for this here, before they are rewritten, to give a more precise
1582 if Nam = TSS_Stream_Input then
1585 elsif Is_List_Member (N)
1586 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
1593 ("invalid context for attribute%, which is a procedure", N);
1597 Btyp := Implementation_Base_Type (P_Type);
1599 -- Stream attributes not allowed on limited types unless the
1600 -- attribute reference was generated by the expander (in which
1601 -- case the underlying type will be used, as described in Sinfo),
1602 -- or the attribute was specified explicitly for the type itself
1603 -- or one of its ancestors (taking visibility rules into account if
1604 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
1605 -- (with no visibility restriction).
1608 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
1610 if Present (Gen_Body) then
1611 In_Shared_Var_Procs :=
1612 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
1614 In_Shared_Var_Procs := False;
1618 if (Comes_From_Source (N)
1619 and then not (In_Shared_Var_Procs or In_Instance))
1620 and then not Stream_Attribute_Available (P_Type, Nam)
1621 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
1623 Error_Msg_Name_1 := Aname;
1625 if Is_Limited_Type (P_Type) then
1627 ("limited type& has no% attribute", P, P_Type);
1628 Explain_Limited_Type (P_Type, P);
1631 ("attribute% for type& is not available", P, P_Type);
1635 -- Check restriction violations
1637 -- First check the No_Streams restriction, which prohibits the use
1638 -- of explicit stream attributes in the source program. We do not
1639 -- prevent the occurrence of stream attributes in generated code,
1640 -- for instance those generated implicitly for dispatching purposes.
1642 if Comes_From_Source (N) then
1643 Check_Restriction (No_Streams, P);
1646 -- Check special case of Exception_Id and Exception_Occurrence which
1647 -- are not allowed for restriction No_Exception_Registration.
1649 if Is_RTE (P_Type, RE_Exception_Id)
1651 Is_RTE (P_Type, RE_Exception_Occurrence)
1653 Check_Restriction (No_Exception_Registration, P);
1656 -- Here we must check that the first argument is an access type
1657 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1659 Analyze_And_Resolve (E1);
1662 -- Note: the double call to Root_Type here is needed because the
1663 -- root type of a class-wide type is the corresponding type (e.g.
1664 -- X for X'Class, and we really want to go to the root.)
1666 if not Is_Access_Type (Etyp)
1667 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1668 RTE (RE_Root_Stream_Type)
1671 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1674 -- Check that the second argument is of the right type if there is
1675 -- one (the Input attribute has only one argument so this is skipped)
1677 if Present (E2) then
1680 if Nam = TSS_Stream_Read
1681 and then not Is_OK_Variable_For_Out_Formal (E2)
1684 ("second argument of % attribute must be a variable", E2);
1687 Resolve (E2, P_Type);
1691 end Check_Stream_Attribute;
1693 -----------------------
1694 -- Check_Task_Prefix --
1695 -----------------------
1697 procedure Check_Task_Prefix is
1701 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1702 -- task interface class-wide types.
1704 if Is_Task_Type (Etype (P))
1705 or else (Is_Access_Type (Etype (P))
1706 and then Is_Task_Type (Designated_Type (Etype (P))))
1707 or else (Ada_Version >= Ada_2005
1708 and then Ekind (Etype (P)) = E_Class_Wide_Type
1709 and then Is_Interface (Etype (P))
1710 and then Is_Task_Interface (Etype (P)))
1715 if Ada_Version >= Ada_2005 then
1717 ("prefix of % attribute must be a task or a task " &
1718 "interface class-wide object");
1721 Error_Attr_P ("prefix of % attribute must be a task");
1724 end Check_Task_Prefix;
1730 -- The possibilities are an entity name denoting a type, or an
1731 -- attribute reference that denotes a type (Base or Class). If
1732 -- the type is incomplete, replace it with its full view.
1734 procedure Check_Type is
1736 if not Is_Entity_Name (P)
1737 or else not Is_Type (Entity (P))
1739 Error_Attr_P ("prefix of % attribute must be a type");
1741 elsif Is_Protected_Self_Reference (P) then
1743 ("prefix of % attribute denotes current instance "
1744 & "(RM 9.4(21/2))");
1746 elsif Ekind (Entity (P)) = E_Incomplete_Type
1747 and then Present (Full_View (Entity (P)))
1749 P_Type := Full_View (Entity (P));
1750 Set_Entity (P, P_Type);
1754 ---------------------
1755 -- Check_Unit_Name --
1756 ---------------------
1758 procedure Check_Unit_Name (Nod : Node_Id) is
1760 if Nkind (Nod) = N_Identifier then
1763 elsif Nkind (Nod) = N_Selected_Component then
1764 Check_Unit_Name (Prefix (Nod));
1766 if Nkind (Selector_Name (Nod)) = N_Identifier then
1771 Error_Attr ("argument for % attribute must be unit name", P);
1772 end Check_Unit_Name;
1778 procedure Error_Attr is
1780 Set_Etype (N, Any_Type);
1781 Set_Entity (N, Any_Type);
1782 raise Bad_Attribute;
1785 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1787 Error_Msg_Name_1 := Aname;
1788 Error_Msg_N (Msg, Error_Node);
1796 procedure Error_Attr_P (Msg : String) is
1798 Error_Msg_Name_1 := Aname;
1799 Error_Msg_F (Msg, P);
1803 ----------------------------
1804 -- Legal_Formal_Attribute --
1805 ----------------------------
1807 procedure Legal_Formal_Attribute is
1811 if not Is_Entity_Name (P)
1812 or else not Is_Type (Entity (P))
1814 Error_Attr_P ("prefix of % attribute must be generic type");
1816 elsif Is_Generic_Actual_Type (Entity (P))
1818 or else In_Inlined_Body
1822 elsif Is_Generic_Type (Entity (P)) then
1823 if not Is_Indefinite_Subtype (Entity (P)) then
1825 ("prefix of % attribute must be indefinite generic type");
1830 ("prefix of % attribute must be indefinite generic type");
1833 Set_Etype (N, Standard_Boolean);
1834 end Legal_Formal_Attribute;
1836 ------------------------
1837 -- Standard_Attribute --
1838 ------------------------
1840 procedure Standard_Attribute (Val : Int) is
1842 Check_Standard_Prefix;
1843 Rewrite (N, Make_Integer_Literal (Loc, Val));
1845 end Standard_Attribute;
1847 -------------------------
1848 -- Unexpected Argument --
1849 -------------------------
1851 procedure Unexpected_Argument (En : Node_Id) is
1853 Error_Attr ("unexpected argument for % attribute", En);
1854 end Unexpected_Argument;
1856 -------------------------------------------------
1857 -- Validate_Non_Static_Attribute_Function_Call --
1858 -------------------------------------------------
1860 -- This function should be moved to Sem_Dist ???
1862 procedure Validate_Non_Static_Attribute_Function_Call is
1864 if In_Preelaborated_Unit
1865 and then not In_Subprogram_Or_Concurrent_Unit
1867 Flag_Non_Static_Expr
1868 ("non-static function call in preelaborated unit!", N);
1870 end Validate_Non_Static_Attribute_Function_Call;
1872 -----------------------------------------------
1873 -- Start of Processing for Analyze_Attribute --
1874 -----------------------------------------------
1877 -- Immediate return if unrecognized attribute (already diagnosed
1878 -- by parser, so there is nothing more that we need to do)
1880 if not Is_Attribute_Name (Aname) then
1881 raise Bad_Attribute;
1884 -- Deal with Ada 83 issues
1886 if Comes_From_Source (N) then
1887 if not Attribute_83 (Attr_Id) then
1888 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1889 Error_Msg_Name_1 := Aname;
1890 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1893 if Attribute_Impl_Def (Attr_Id) then
1894 Check_Restriction (No_Implementation_Attributes, N);
1899 -- Deal with Ada 2005 issues
1901 if Attribute_05 (Attr_Id) and then Ada_Version <= Ada_95 then
1902 Check_Restriction (No_Implementation_Attributes, N);
1905 -- Remote access to subprogram type access attribute reference needs
1906 -- unanalyzed copy for tree transformation. The analyzed copy is used
1907 -- for its semantic information (whether prefix is a remote subprogram
1908 -- name), the unanalyzed copy is used to construct new subtree rooted
1909 -- with N_Aggregate which represents a fat pointer aggregate.
1911 if Aname = Name_Access then
1912 Discard_Node (Copy_Separate_Tree (N));
1915 -- Analyze prefix and exit if error in analysis. If the prefix is an
1916 -- incomplete type, use full view if available. Note that there are
1917 -- some attributes for which we do not analyze the prefix, since the
1918 -- prefix is not a normal name.
1920 if Aname /= Name_Elab_Body
1922 Aname /= Name_Elab_Spec
1924 Aname /= Name_UET_Address
1926 Aname /= Name_Enabled
1929 P_Type := Etype (P);
1931 if Is_Entity_Name (P)
1932 and then Present (Entity (P))
1933 and then Is_Type (Entity (P))
1935 if Ekind (Entity (P)) = E_Incomplete_Type then
1936 P_Type := Get_Full_View (P_Type);
1937 Set_Entity (P, P_Type);
1938 Set_Etype (P, P_Type);
1940 elsif Entity (P) = Current_Scope
1941 and then Is_Record_Type (Entity (P))
1943 -- Use of current instance within the type. Verify that if the
1944 -- attribute appears within a constraint, it yields an access
1945 -- type, other uses are illegal.
1953 and then Nkind (Parent (Par)) /= N_Component_Definition
1955 Par := Parent (Par);
1959 and then Nkind (Par) = N_Subtype_Indication
1961 if Attr_Id /= Attribute_Access
1962 and then Attr_Id /= Attribute_Unchecked_Access
1963 and then Attr_Id /= Attribute_Unrestricted_Access
1966 ("in a constraint the current instance can only"
1967 & " be used with an access attribute", N);
1974 if P_Type = Any_Type then
1975 raise Bad_Attribute;
1978 P_Base_Type := Base_Type (P_Type);
1981 -- Analyze expressions that may be present, exiting if an error occurs
1988 E1 := First (Exprs);
1991 -- Check for missing/bad expression (result of previous error)
1993 if No (E1) or else Etype (E1) = Any_Type then
1994 raise Bad_Attribute;
1999 if Present (E2) then
2002 if Etype (E2) = Any_Type then
2003 raise Bad_Attribute;
2006 if Present (Next (E2)) then
2007 Unexpected_Argument (Next (E2));
2012 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
2013 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
2015 if Ada_Version < Ada_2005
2016 and then Is_Overloaded (P)
2017 and then Aname /= Name_Access
2018 and then Aname /= Name_Address
2019 and then Aname /= Name_Code_Address
2020 and then Aname /= Name_Count
2021 and then Aname /= Name_Result
2022 and then Aname /= Name_Unchecked_Access
2024 Error_Attr ("ambiguous prefix for % attribute", P);
2026 elsif Ada_Version >= Ada_2005
2027 and then Is_Overloaded (P)
2028 and then Aname /= Name_Access
2029 and then Aname /= Name_Address
2030 and then Aname /= Name_Code_Address
2031 and then Aname /= Name_Result
2032 and then Aname /= Name_Unchecked_Access
2034 -- Ada 2005 (AI-345): Since protected and task types have primitive
2035 -- entry wrappers, the attributes Count, Caller and AST_Entry require
2038 if Ada_Version >= Ada_2005
2039 and then (Aname = Name_Count
2040 or else Aname = Name_Caller
2041 or else Aname = Name_AST_Entry)
2044 Count : Natural := 0;
2049 Get_First_Interp (P, I, It);
2050 while Present (It.Nam) loop
2051 if Comes_From_Source (It.Nam) then
2057 Get_Next_Interp (I, It);
2061 Error_Attr ("ambiguous prefix for % attribute", P);
2063 Set_Is_Overloaded (P, False);
2068 Error_Attr ("ambiguous prefix for % attribute", P);
2072 -- In SPARK or ALFA, attributes of private types are only allowed if
2073 -- the full type declaration is visible.
2075 if Formal_Verification_Mode
2076 and then Comes_From_Source (Original_Node (N))
2077 and then Is_Entity_Name (P)
2078 and then Is_Type (Entity (P))
2079 and then Is_Private_Type (P_Type)
2080 and then not In_Open_Scopes (Scope (P_Type))
2081 and then not In_Spec_Expression
2084 ("|~~invisible attribute of}", N, First_Subtype (P_Type));
2087 -- Remaining processing depends on attribute
2095 when Attribute_Abort_Signal =>
2096 Check_Standard_Prefix;
2097 Rewrite (N, New_Reference_To (Stand.Abort_Signal, Loc));
2104 when Attribute_Access =>
2105 Analyze_Access_Attribute;
2111 when Attribute_Address =>
2114 -- Check for some junk cases, where we have to allow the address
2115 -- attribute but it does not make much sense, so at least for now
2116 -- just replace with Null_Address.
2118 -- We also do this if the prefix is a reference to the AST_Entry
2119 -- attribute. If expansion is active, the attribute will be
2120 -- replaced by a function call, and address will work fine and
2121 -- get the proper value, but if expansion is not active, then
2122 -- the check here allows proper semantic analysis of the reference.
2124 -- An Address attribute created by expansion is legal even when it
2125 -- applies to other entity-denoting expressions.
2127 if Is_Protected_Self_Reference (P) then
2129 -- Address attribute on a protected object self reference is legal
2133 elsif Is_Entity_Name (P) then
2135 Ent : constant Entity_Id := Entity (P);
2138 if Is_Subprogram (Ent) then
2139 Set_Address_Taken (Ent);
2140 Kill_Current_Values (Ent);
2142 -- An Address attribute is accepted when generated by the
2143 -- compiler for dispatching operation, and an error is
2144 -- issued once the subprogram is frozen (to avoid confusing
2145 -- errors about implicit uses of Address in the dispatch
2146 -- table initialization).
2148 if Has_Pragma_Inline_Always (Entity (P))
2149 and then Comes_From_Source (P)
2152 ("prefix of % attribute cannot be Inline_Always" &
2155 -- It is illegal to apply 'Address to an intrinsic
2156 -- subprogram. This is now formalized in AI05-0095.
2157 -- In an instance, an attempt to obtain 'Address of an
2158 -- intrinsic subprogram (e.g the renaming of a predefined
2159 -- operator that is an actual) raises Program_Error.
2161 elsif Convention (Ent) = Convention_Intrinsic then
2164 Make_Raise_Program_Error (Loc,
2165 Reason => PE_Address_Of_Intrinsic));
2169 ("cannot take Address of intrinsic subprogram", N);
2172 -- Issue an error if prefix denotes an eliminated subprogram
2175 Check_For_Eliminated_Subprogram (P, Ent);
2178 elsif Is_Object (Ent)
2179 or else Ekind (Ent) = E_Label
2181 Set_Address_Taken (Ent);
2183 -- If we have an address of an object, and the attribute
2184 -- comes from source, then set the object as potentially
2185 -- source modified. We do this because the resulting address
2186 -- can potentially be used to modify the variable and we
2187 -- might not detect this, leading to some junk warnings.
2189 Set_Never_Set_In_Source (Ent, False);
2191 elsif (Is_Concurrent_Type (Etype (Ent))
2192 and then Etype (Ent) = Base_Type (Ent))
2193 or else Ekind (Ent) = E_Package
2194 or else Is_Generic_Unit (Ent)
2197 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2200 Error_Attr ("invalid prefix for % attribute", P);
2204 elsif Nkind (P) = N_Attribute_Reference
2205 and then Attribute_Name (P) = Name_AST_Entry
2208 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2210 elsif Is_Object_Reference (P) then
2213 elsif Nkind (P) = N_Selected_Component
2214 and then Is_Subprogram (Entity (Selector_Name (P)))
2218 -- What exactly are we allowing here ??? and is this properly
2219 -- documented in the sinfo documentation for this node ???
2221 elsif not Comes_From_Source (N) then
2225 Error_Attr ("invalid prefix for % attribute", P);
2228 Set_Etype (N, RTE (RE_Address));
2234 when Attribute_Address_Size =>
2235 Standard_Attribute (System_Address_Size);
2241 when Attribute_Adjacent =>
2242 Check_Floating_Point_Type_2;
2243 Set_Etype (N, P_Base_Type);
2244 Resolve (E1, P_Base_Type);
2245 Resolve (E2, P_Base_Type);
2251 when Attribute_Aft =>
2252 Check_Fixed_Point_Type_0;
2253 Set_Etype (N, Universal_Integer);
2259 when Attribute_Alignment =>
2261 -- Don't we need more checking here, cf Size ???
2264 Check_Not_Incomplete_Type;
2266 Set_Etype (N, Universal_Integer);
2272 when Attribute_Asm_Input =>
2273 Check_Asm_Attribute;
2275 -- The back-end may need to take the address of E2
2277 if Is_Entity_Name (E2) then
2278 Set_Address_Taken (Entity (E2));
2281 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2287 when Attribute_Asm_Output =>
2288 Check_Asm_Attribute;
2290 if Etype (E2) = Any_Type then
2293 elsif Aname = Name_Asm_Output then
2294 if not Is_Variable (E2) then
2296 ("second argument for Asm_Output is not variable", E2);
2300 Note_Possible_Modification (E2, Sure => True);
2302 -- The back-end may need to take the address of E2
2304 if Is_Entity_Name (E2) then
2305 Set_Address_Taken (Entity (E2));
2308 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2314 when Attribute_AST_Entry => AST_Entry : declare
2320 -- Indicates if entry family index is present. Note the coding
2321 -- here handles the entry family case, but in fact it cannot be
2322 -- executed currently, because pragma AST_Entry does not permit
2323 -- the specification of an entry family.
2325 procedure Bad_AST_Entry;
2326 -- Signal a bad AST_Entry pragma
2328 function OK_Entry (E : Entity_Id) return Boolean;
2329 -- Checks that E is of an appropriate entity kind for an entry
2330 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2331 -- is set True for the entry family case). In the True case,
2332 -- makes sure that Is_AST_Entry is set on the entry.
2338 procedure Bad_AST_Entry is
2340 Error_Attr_P ("prefix for % attribute must be task entry");
2347 function OK_Entry (E : Entity_Id) return Boolean is
2352 Result := (Ekind (E) = E_Entry_Family);
2354 Result := (Ekind (E) = E_Entry);
2358 if not Is_AST_Entry (E) then
2359 Error_Msg_Name_2 := Aname;
2360 Error_Attr ("% attribute requires previous % pragma", P);
2367 -- Start of processing for AST_Entry
2373 -- Deal with entry family case
2375 if Nkind (P) = N_Indexed_Component then
2383 Ptyp := Etype (Pref);
2385 if Ptyp = Any_Type or else Error_Posted (Pref) then
2389 -- If the prefix is a selected component whose prefix is of an
2390 -- access type, then introduce an explicit dereference.
2391 -- ??? Could we reuse Check_Dereference here?
2393 if Nkind (Pref) = N_Selected_Component
2394 and then Is_Access_Type (Ptyp)
2397 Make_Explicit_Dereference (Sloc (Pref),
2398 Relocate_Node (Pref)));
2399 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2402 -- Prefix can be of the form a.b, where a is a task object
2403 -- and b is one of the entries of the corresponding task type.
2405 if Nkind (Pref) = N_Selected_Component
2406 and then OK_Entry (Entity (Selector_Name (Pref)))
2407 and then Is_Object_Reference (Prefix (Pref))
2408 and then Is_Task_Type (Etype (Prefix (Pref)))
2412 -- Otherwise the prefix must be an entry of a containing task,
2413 -- or of a variable of the enclosing task type.
2416 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2417 Ent := Entity (Pref);
2419 if not OK_Entry (Ent)
2420 or else not In_Open_Scopes (Scope (Ent))
2430 Set_Etype (N, RTE (RE_AST_Handler));
2437 -- Note: when the base attribute appears in the context of a subtype
2438 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2439 -- the following circuit.
2441 when Attribute_Base => Base : declare
2449 if Ada_Version >= Ada_95
2450 and then not Is_Scalar_Type (Typ)
2451 and then not Is_Generic_Type (Typ)
2453 Error_Attr_P ("prefix of Base attribute must be scalar type");
2455 elsif Sloc (Typ) = Standard_Location
2456 and then Base_Type (Typ) = Typ
2457 and then Warn_On_Redundant_Constructs
2459 Error_Msg_NE -- CODEFIX
2460 ("?redundant attribute, & is its own base type", N, Typ);
2463 if Nkind (Parent (N)) /= N_Attribute_Reference then
2464 Error_Msg_Name_1 := Aname;
2465 Check_Formal_Restriction
2466 ("attribute% is only allowed as prefix of another attribute", P);
2469 Set_Etype (N, Base_Type (Entity (P)));
2470 Set_Entity (N, Base_Type (Entity (P)));
2471 Rewrite (N, New_Reference_To (Entity (N), Loc));
2479 when Attribute_Bit => Bit :
2483 if not Is_Object_Reference (P) then
2484 Error_Attr_P ("prefix for % attribute must be object");
2486 -- What about the access object cases ???
2492 Set_Etype (N, Universal_Integer);
2499 when Attribute_Bit_Order => Bit_Order :
2504 if not Is_Record_Type (P_Type) then
2505 Error_Attr_P ("prefix of % attribute must be record type");
2508 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2510 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2513 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2516 Set_Etype (N, RTE (RE_Bit_Order));
2519 -- Reset incorrect indication of staticness
2521 Set_Is_Static_Expression (N, False);
2528 -- Note: in generated code, we can have a Bit_Position attribute
2529 -- applied to a (naked) record component (i.e. the prefix is an
2530 -- identifier that references an E_Component or E_Discriminant
2531 -- entity directly, and this is interpreted as expected by Gigi.
2532 -- The following code will not tolerate such usage, but when the
2533 -- expander creates this special case, it marks it as analyzed
2534 -- immediately and sets an appropriate type.
2536 when Attribute_Bit_Position =>
2537 if Comes_From_Source (N) then
2541 Set_Etype (N, Universal_Integer);
2547 when Attribute_Body_Version =>
2550 Set_Etype (N, RTE (RE_Version_String));
2556 when Attribute_Callable =>
2558 Set_Etype (N, Standard_Boolean);
2565 when Attribute_Caller => Caller : declare
2572 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2575 if not Is_Entry (Ent) then
2576 Error_Attr ("invalid entry name", N);
2580 Error_Attr ("invalid entry name", N);
2584 for J in reverse 0 .. Scope_Stack.Last loop
2585 S := Scope_Stack.Table (J).Entity;
2587 if S = Scope (Ent) then
2588 Error_Attr ("Caller must appear in matching accept or body", N);
2594 Set_Etype (N, RTE (RO_AT_Task_Id));
2601 when Attribute_Ceiling =>
2602 Check_Floating_Point_Type_1;
2603 Set_Etype (N, P_Base_Type);
2604 Resolve (E1, P_Base_Type);
2610 when Attribute_Class =>
2611 Check_Restriction (No_Dispatch, N);
2615 -- Applying Class to untagged incomplete type is obsolescent in Ada
2616 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
2617 -- this flag gets set by Find_Type in this situation.
2619 if Restriction_Check_Required (No_Obsolescent_Features)
2620 and then Ada_Version >= Ada_2005
2621 and then Ekind (P_Type) = E_Incomplete_Type
2624 DN : constant Node_Id := Declaration_Node (P_Type);
2626 if Nkind (DN) = N_Incomplete_Type_Declaration
2627 and then not Tagged_Present (DN)
2629 Check_Restriction (No_Obsolescent_Features, P);
2638 when Attribute_Code_Address =>
2641 if Nkind (P) = N_Attribute_Reference
2642 and then (Attribute_Name (P) = Name_Elab_Body
2644 Attribute_Name (P) = Name_Elab_Spec)
2648 elsif not Is_Entity_Name (P)
2649 or else (Ekind (Entity (P)) /= E_Function
2651 Ekind (Entity (P)) /= E_Procedure)
2653 Error_Attr ("invalid prefix for % attribute", P);
2654 Set_Address_Taken (Entity (P));
2656 -- Issue an error if the prefix denotes an eliminated subprogram
2659 Check_For_Eliminated_Subprogram (P, Entity (P));
2662 Set_Etype (N, RTE (RE_Address));
2664 ----------------------
2665 -- Compiler_Version --
2666 ----------------------
2668 when Attribute_Compiler_Version =>
2670 Check_Standard_Prefix;
2671 Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
2672 Analyze_And_Resolve (N, Standard_String);
2674 --------------------
2675 -- Component_Size --
2676 --------------------
2678 when Attribute_Component_Size =>
2680 Set_Etype (N, Universal_Integer);
2682 -- Note: unlike other array attributes, unconstrained arrays are OK
2684 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2694 when Attribute_Compose =>
2695 Check_Floating_Point_Type_2;
2696 Set_Etype (N, P_Base_Type);
2697 Resolve (E1, P_Base_Type);
2698 Resolve (E2, Any_Integer);
2704 when Attribute_Constrained =>
2706 Set_Etype (N, Standard_Boolean);
2708 -- Case from RM J.4(2) of constrained applied to private type
2710 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2711 Check_Restriction (No_Obsolescent_Features, P);
2713 if Warn_On_Obsolescent_Feature then
2715 ("constrained for private type is an " &
2716 "obsolescent feature (RM J.4)?", N);
2719 -- If we are within an instance, the attribute must be legal
2720 -- because it was valid in the generic unit. Ditto if this is
2721 -- an inlining of a function declared in an instance.
2724 or else In_Inlined_Body
2728 -- For sure OK if we have a real private type itself, but must
2729 -- be completed, cannot apply Constrained to incomplete type.
2731 elsif Is_Private_Type (Entity (P)) then
2733 -- Note: this is one of the Annex J features that does not
2734 -- generate a warning from -gnatwj, since in fact it seems
2735 -- very useful, and is used in the GNAT runtime.
2737 Check_Not_Incomplete_Type;
2741 -- Normal (non-obsolescent case) of application to object of
2742 -- a discriminated type.
2745 Check_Object_Reference (P);
2747 -- If N does not come from source, then we allow the
2748 -- the attribute prefix to be of a private type whose
2749 -- full type has discriminants. This occurs in cases
2750 -- involving expanded calls to stream attributes.
2752 if not Comes_From_Source (N) then
2753 P_Type := Underlying_Type (P_Type);
2756 -- Must have discriminants or be an access type designating
2757 -- a type with discriminants. If it is a classwide type is ???
2758 -- has unknown discriminants.
2760 if Has_Discriminants (P_Type)
2761 or else Has_Unknown_Discriminants (P_Type)
2763 (Is_Access_Type (P_Type)
2764 and then Has_Discriminants (Designated_Type (P_Type)))
2768 -- Also allow an object of a generic type if extensions allowed
2769 -- and allow this for any type at all.
2771 elsif (Is_Generic_Type (P_Type)
2772 or else Is_Generic_Actual_Type (P_Type))
2773 and then Extensions_Allowed
2779 -- Fall through if bad prefix
2782 ("prefix of % attribute must be object of discriminated type");
2788 when Attribute_Copy_Sign =>
2789 Check_Floating_Point_Type_2;
2790 Set_Etype (N, P_Base_Type);
2791 Resolve (E1, P_Base_Type);
2792 Resolve (E2, P_Base_Type);
2798 when Attribute_Count => Count :
2807 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2810 if Ekind (Ent) /= E_Entry then
2811 Error_Attr ("invalid entry name", N);
2814 elsif Nkind (P) = N_Indexed_Component then
2815 if not Is_Entity_Name (Prefix (P))
2816 or else No (Entity (Prefix (P)))
2817 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2819 if Nkind (Prefix (P)) = N_Selected_Component
2820 and then Present (Entity (Selector_Name (Prefix (P))))
2821 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2825 ("attribute % must apply to entry of current task", P);
2828 Error_Attr ("invalid entry family name", P);
2833 Ent := Entity (Prefix (P));
2836 elsif Nkind (P) = N_Selected_Component
2837 and then Present (Entity (Selector_Name (P)))
2838 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2841 ("attribute % must apply to entry of current task", P);
2844 Error_Attr ("invalid entry name", N);
2848 for J in reverse 0 .. Scope_Stack.Last loop
2849 S := Scope_Stack.Table (J).Entity;
2851 if S = Scope (Ent) then
2852 if Nkind (P) = N_Expanded_Name then
2853 Tsk := Entity (Prefix (P));
2855 -- The prefix denotes either the task type, or else a
2856 -- single task whose task type is being analyzed.
2861 or else (not Is_Type (Tsk)
2862 and then Etype (Tsk) = S
2863 and then not (Comes_From_Source (S)))
2868 ("Attribute % must apply to entry of current task", N);
2874 elsif Ekind (Scope (Ent)) in Task_Kind
2876 not Ekind_In (S, E_Loop, E_Block, E_Entry, E_Entry_Family)
2878 Error_Attr ("Attribute % cannot appear in inner unit", N);
2880 elsif Ekind (Scope (Ent)) = E_Protected_Type
2881 and then not Has_Completion (Scope (Ent))
2883 Error_Attr ("attribute % can only be used inside body", N);
2887 if Is_Overloaded (P) then
2889 Index : Interp_Index;
2893 Get_First_Interp (P, Index, It);
2895 while Present (It.Nam) loop
2896 if It.Nam = Ent then
2899 -- Ada 2005 (AI-345): Do not consider primitive entry
2900 -- wrappers generated for task or protected types.
2902 elsif Ada_Version >= Ada_2005
2903 and then not Comes_From_Source (It.Nam)
2908 Error_Attr ("ambiguous entry name", N);
2911 Get_Next_Interp (Index, It);
2916 Set_Etype (N, Universal_Integer);
2919 -----------------------
2920 -- Default_Bit_Order --
2921 -----------------------
2923 when Attribute_Default_Bit_Order => Default_Bit_Order :
2925 Check_Standard_Prefix;
2927 if Bytes_Big_Endian then
2929 Make_Integer_Literal (Loc, False_Value));
2932 Make_Integer_Literal (Loc, True_Value));
2935 Set_Etype (N, Universal_Integer);
2936 Set_Is_Static_Expression (N);
2937 end Default_Bit_Order;
2943 when Attribute_Definite =>
2944 Legal_Formal_Attribute;
2950 when Attribute_Delta =>
2951 Check_Fixed_Point_Type_0;
2952 Set_Etype (N, Universal_Real);
2958 when Attribute_Denorm =>
2959 Check_Floating_Point_Type_0;
2960 Set_Etype (N, Standard_Boolean);
2966 when Attribute_Digits =>
2970 if not Is_Floating_Point_Type (P_Type)
2971 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2974 ("prefix of % attribute must be float or decimal type");
2977 Set_Etype (N, Universal_Integer);
2983 -- Also handles processing for Elab_Spec
2985 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2987 Check_Unit_Name (P);
2988 Set_Etype (N, Standard_Void_Type);
2990 -- We have to manually call the expander in this case to get
2991 -- the necessary expansion (normally attributes that return
2992 -- entities are not expanded).
3000 -- Shares processing with Elab_Body
3006 when Attribute_Elaborated =>
3009 Set_Etype (N, Standard_Boolean);
3015 when Attribute_Emax =>
3016 Check_Floating_Point_Type_0;
3017 Set_Etype (N, Universal_Integer);
3023 when Attribute_Enabled =>
3024 Check_Either_E0_Or_E1;
3026 if Present (E1) then
3027 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
3028 Error_Msg_N ("entity name expected for Enabled attribute", E1);
3033 if Nkind (P) /= N_Identifier then
3034 Error_Msg_N ("identifier expected (check name)", P);
3035 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
3036 Error_Msg_N ("& is not a recognized check name", P);
3039 Set_Etype (N, Standard_Boolean);
3045 when Attribute_Enum_Rep => Enum_Rep : declare
3047 if Present (E1) then
3049 Check_Discrete_Type;
3050 Resolve (E1, P_Base_Type);
3053 if not Is_Entity_Name (P)
3054 or else (not Is_Object (Entity (P))
3056 Ekind (Entity (P)) /= E_Enumeration_Literal)
3059 ("prefix of % attribute must be " &
3060 "discrete type/object or enum literal");
3064 Set_Etype (N, Universal_Integer);
3071 when Attribute_Enum_Val => Enum_Val : begin
3075 if not Is_Enumeration_Type (P_Type) then
3076 Error_Attr_P ("prefix of % attribute must be enumeration type");
3079 -- If the enumeration type has a standard representation, the effect
3080 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3082 if not Has_Non_Standard_Rep (P_Base_Type) then
3084 Make_Attribute_Reference (Loc,
3085 Prefix => Relocate_Node (Prefix (N)),
3086 Attribute_Name => Name_Val,
3087 Expressions => New_List (Relocate_Node (E1))));
3088 Analyze_And_Resolve (N, P_Base_Type);
3090 -- Non-standard representation case (enumeration with holes)
3094 Resolve (E1, Any_Integer);
3095 Set_Etype (N, P_Base_Type);
3103 when Attribute_Epsilon =>
3104 Check_Floating_Point_Type_0;
3105 Set_Etype (N, Universal_Real);
3111 when Attribute_Exponent =>
3112 Check_Floating_Point_Type_1;
3113 Set_Etype (N, Universal_Integer);
3114 Resolve (E1, P_Base_Type);
3120 when Attribute_External_Tag =>
3124 Set_Etype (N, Standard_String);
3126 if not Is_Tagged_Type (P_Type) then
3127 Error_Attr_P ("prefix of % attribute must be tagged");
3134 when Attribute_Fast_Math =>
3135 Check_Standard_Prefix;
3137 if Opt.Fast_Math then
3138 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
3140 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
3147 when Attribute_First =>
3148 Check_Array_Or_Scalar_Type;
3149 Bad_Attribute_For_Predicate;
3155 when Attribute_First_Bit =>
3157 Set_Etype (N, Universal_Integer);
3163 when Attribute_Fixed_Value =>
3165 Check_Fixed_Point_Type;
3166 Resolve (E1, Any_Integer);
3167 Set_Etype (N, P_Base_Type);
3173 when Attribute_Floor =>
3174 Check_Floating_Point_Type_1;
3175 Set_Etype (N, P_Base_Type);
3176 Resolve (E1, P_Base_Type);
3182 when Attribute_Fore =>
3183 Check_Fixed_Point_Type_0;
3184 Set_Etype (N, Universal_Integer);
3190 when Attribute_Fraction =>
3191 Check_Floating_Point_Type_1;
3192 Set_Etype (N, P_Base_Type);
3193 Resolve (E1, P_Base_Type);
3199 when Attribute_From_Any =>
3201 Check_PolyORB_Attribute;
3202 Set_Etype (N, P_Base_Type);
3204 -----------------------
3205 -- Has_Access_Values --
3206 -----------------------
3208 when Attribute_Has_Access_Values =>
3211 Set_Etype (N, Standard_Boolean);
3213 -----------------------
3214 -- Has_Tagged_Values --
3215 -----------------------
3217 when Attribute_Has_Tagged_Values =>
3220 Set_Etype (N, Standard_Boolean);
3222 -----------------------
3223 -- Has_Discriminants --
3224 -----------------------
3226 when Attribute_Has_Discriminants =>
3227 Legal_Formal_Attribute;
3233 when Attribute_Identity =>
3237 if Etype (P) = Standard_Exception_Type then
3238 Set_Etype (N, RTE (RE_Exception_Id));
3240 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3241 -- task interface class-wide types.
3243 elsif Is_Task_Type (Etype (P))
3244 or else (Is_Access_Type (Etype (P))
3245 and then Is_Task_Type (Designated_Type (Etype (P))))
3246 or else (Ada_Version >= Ada_2005
3247 and then Ekind (Etype (P)) = E_Class_Wide_Type
3248 and then Is_Interface (Etype (P))
3249 and then Is_Task_Interface (Etype (P)))
3252 Set_Etype (N, RTE (RO_AT_Task_Id));
3255 if Ada_Version >= Ada_2005 then
3257 ("prefix of % attribute must be an exception, a " &
3258 "task or a task interface class-wide object");
3261 ("prefix of % attribute must be a task or an exception");
3269 when Attribute_Image => Image :
3271 Check_Formal_Restriction_On_Attribute;
3273 Set_Etype (N, Standard_String);
3275 if Is_Real_Type (P_Type) then
3276 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3277 Error_Msg_Name_1 := Aname;
3279 ("(Ada 83) % attribute not allowed for real types", N);
3283 if Is_Enumeration_Type (P_Type) then
3284 Check_Restriction (No_Enumeration_Maps, N);
3288 Resolve (E1, P_Base_Type);
3290 Validate_Non_Static_Attribute_Function_Call;
3297 when Attribute_Img => Img :
3300 Set_Etype (N, Standard_String);
3302 if not Is_Scalar_Type (P_Type)
3303 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3306 ("prefix of % attribute must be scalar object name");
3316 when Attribute_Input =>
3318 Check_Stream_Attribute (TSS_Stream_Input);
3319 Set_Etype (N, P_Base_Type);
3325 when Attribute_Integer_Value =>
3328 Resolve (E1, Any_Fixed);
3330 -- Signal an error if argument type is not a specific fixed-point
3331 -- subtype. An error has been signalled already if the argument
3332 -- was not of a fixed-point type.
3334 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3335 Error_Attr ("argument of % must be of a fixed-point type", E1);
3338 Set_Etype (N, P_Base_Type);
3344 when Attribute_Invalid_Value =>
3347 Set_Etype (N, P_Base_Type);
3348 Invalid_Value_Used := True;
3354 when Attribute_Large =>
3357 Set_Etype (N, Universal_Real);
3363 when Attribute_Last =>
3364 Check_Array_Or_Scalar_Type;
3365 Bad_Attribute_For_Predicate;
3371 when Attribute_Last_Bit =>
3373 Set_Etype (N, Universal_Integer);
3379 when Attribute_Leading_Part =>
3380 Check_Floating_Point_Type_2;
3381 Set_Etype (N, P_Base_Type);
3382 Resolve (E1, P_Base_Type);
3383 Resolve (E2, Any_Integer);
3389 when Attribute_Length =>
3391 Set_Etype (N, Universal_Integer);
3397 when Attribute_Machine =>
3398 Check_Floating_Point_Type_1;
3399 Set_Etype (N, P_Base_Type);
3400 Resolve (E1, P_Base_Type);
3406 when Attribute_Machine_Emax =>
3407 Check_Floating_Point_Type_0;
3408 Set_Etype (N, Universal_Integer);
3414 when Attribute_Machine_Emin =>
3415 Check_Floating_Point_Type_0;
3416 Set_Etype (N, Universal_Integer);
3418 ----------------------
3419 -- Machine_Mantissa --
3420 ----------------------
3422 when Attribute_Machine_Mantissa =>
3423 Check_Floating_Point_Type_0;
3424 Set_Etype (N, Universal_Integer);
3426 -----------------------
3427 -- Machine_Overflows --
3428 -----------------------
3430 when Attribute_Machine_Overflows =>
3433 Set_Etype (N, Standard_Boolean);
3439 when Attribute_Machine_Radix =>
3442 Set_Etype (N, Universal_Integer);
3444 ----------------------
3445 -- Machine_Rounding --
3446 ----------------------
3448 when Attribute_Machine_Rounding =>
3449 Check_Floating_Point_Type_1;
3450 Set_Etype (N, P_Base_Type);
3451 Resolve (E1, P_Base_Type);
3453 --------------------
3454 -- Machine_Rounds --
3455 --------------------
3457 when Attribute_Machine_Rounds =>
3460 Set_Etype (N, Standard_Boolean);
3466 when Attribute_Machine_Size =>
3469 Check_Not_Incomplete_Type;
3470 Set_Etype (N, Universal_Integer);
3476 when Attribute_Mantissa =>
3479 Set_Etype (N, Universal_Integer);
3485 when Attribute_Max =>
3488 Resolve (E1, P_Base_Type);
3489 Resolve (E2, P_Base_Type);
3490 Set_Etype (N, P_Base_Type);
3492 ----------------------------------
3493 -- Max_Alignment_For_Allocation --
3494 -- Max_Size_In_Storage_Elements --
3495 ----------------------------------
3497 when Attribute_Max_Alignment_For_Allocation |
3498 Attribute_Max_Size_In_Storage_Elements =>
3501 Check_Not_Incomplete_Type;
3502 Set_Etype (N, Universal_Integer);
3504 -----------------------
3505 -- Maximum_Alignment --
3506 -----------------------
3508 when Attribute_Maximum_Alignment =>
3509 Standard_Attribute (Ttypes.Maximum_Alignment);
3511 --------------------
3512 -- Mechanism_Code --
3513 --------------------
3515 when Attribute_Mechanism_Code =>
3516 if not Is_Entity_Name (P)
3517 or else not Is_Subprogram (Entity (P))
3519 Error_Attr_P ("prefix of % attribute must be subprogram");
3522 Check_Either_E0_Or_E1;
3524 if Present (E1) then
3525 Resolve (E1, Any_Integer);
3526 Set_Etype (E1, Standard_Integer);
3528 if not Is_Static_Expression (E1) then
3529 Flag_Non_Static_Expr
3530 ("expression for parameter number must be static!", E1);
3533 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3534 or else UI_To_Int (Intval (E1)) < 0
3536 Error_Attr ("invalid parameter number for % attribute", E1);
3540 Set_Etype (N, Universal_Integer);
3546 when Attribute_Min =>
3549 Resolve (E1, P_Base_Type);
3550 Resolve (E2, P_Base_Type);
3551 Set_Etype (N, P_Base_Type);
3557 when Attribute_Mod =>
3559 -- Note: this attribute is only allowed in Ada 2005 mode, but
3560 -- we do not need to test that here, since Mod is only recognized
3561 -- as an attribute name in Ada 2005 mode during the parse.
3564 Check_Modular_Integer_Type;
3565 Resolve (E1, Any_Integer);
3566 Set_Etype (N, P_Base_Type);
3572 when Attribute_Model =>
3573 Check_Floating_Point_Type_1;
3574 Set_Etype (N, P_Base_Type);
3575 Resolve (E1, P_Base_Type);
3581 when Attribute_Model_Emin =>
3582 Check_Floating_Point_Type_0;
3583 Set_Etype (N, Universal_Integer);
3589 when Attribute_Model_Epsilon =>
3590 Check_Floating_Point_Type_0;
3591 Set_Etype (N, Universal_Real);
3593 --------------------
3594 -- Model_Mantissa --
3595 --------------------
3597 when Attribute_Model_Mantissa =>
3598 Check_Floating_Point_Type_0;
3599 Set_Etype (N, Universal_Integer);
3605 when Attribute_Model_Small =>
3606 Check_Floating_Point_Type_0;
3607 Set_Etype (N, Universal_Real);
3613 when Attribute_Modulus =>
3615 Check_Modular_Integer_Type;
3616 Set_Etype (N, Universal_Integer);
3618 --------------------
3619 -- Null_Parameter --
3620 --------------------
3622 when Attribute_Null_Parameter => Null_Parameter : declare
3623 Parnt : constant Node_Id := Parent (N);
3624 GParnt : constant Node_Id := Parent (Parnt);
3626 procedure Bad_Null_Parameter (Msg : String);
3627 -- Used if bad Null parameter attribute node is found. Issues
3628 -- given error message, and also sets the type to Any_Type to
3629 -- avoid blowups later on from dealing with a junk node.
3631 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3632 -- Called to check that Proc_Ent is imported subprogram
3634 ------------------------
3635 -- Bad_Null_Parameter --
3636 ------------------------
3638 procedure Bad_Null_Parameter (Msg : String) is
3640 Error_Msg_N (Msg, N);
3641 Set_Etype (N, Any_Type);
3642 end Bad_Null_Parameter;
3644 ----------------------
3645 -- Must_Be_Imported --
3646 ----------------------
3648 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3649 Pent : constant Entity_Id := Ultimate_Alias (Proc_Ent);
3652 -- Ignore check if procedure not frozen yet (we will get
3653 -- another chance when the default parameter is reanalyzed)
3655 if not Is_Frozen (Pent) then
3658 elsif not Is_Imported (Pent) then
3660 ("Null_Parameter can only be used with imported subprogram");
3665 end Must_Be_Imported;
3667 -- Start of processing for Null_Parameter
3672 Set_Etype (N, P_Type);
3674 -- Case of attribute used as default expression
3676 if Nkind (Parnt) = N_Parameter_Specification then
3677 Must_Be_Imported (Defining_Entity (GParnt));
3679 -- Case of attribute used as actual for subprogram (positional)
3681 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3683 and then Is_Entity_Name (Name (Parnt))
3685 Must_Be_Imported (Entity (Name (Parnt)));
3687 -- Case of attribute used as actual for subprogram (named)
3689 elsif Nkind (Parnt) = N_Parameter_Association
3690 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3692 and then Is_Entity_Name (Name (GParnt))
3694 Must_Be_Imported (Entity (Name (GParnt)));
3696 -- Not an allowed case
3700 ("Null_Parameter must be actual or default parameter");
3708 when Attribute_Object_Size =>
3711 Check_Not_Incomplete_Type;
3712 Set_Etype (N, Universal_Integer);
3718 when Attribute_Old =>
3720 -- The attribute reference is a primary. If expressions follow, the
3721 -- attribute reference is an indexable object, so rewrite the node
3724 if Present (E1) then
3726 Make_Indexed_Component (Loc,
3728 Make_Attribute_Reference (Loc,
3729 Prefix => Relocate_Node (Prefix (N)),
3730 Attribute_Name => Name_Old),
3731 Expressions => Expressions (N)));
3738 Set_Etype (N, P_Type);
3740 if No (Current_Subprogram) then
3741 Error_Attr ("attribute % can only appear within subprogram", N);
3744 if Is_Limited_Type (P_Type) then
3745 Error_Attr ("attribute % cannot apply to limited objects", P);
3748 if Is_Entity_Name (P)
3749 and then Is_Constant_Object (Entity (P))
3752 ("?attribute Old applied to constant has no effect", P);
3755 -- Check that the expression does not refer to local entities
3757 Check_Local : declare
3758 Subp : Entity_Id := Current_Subprogram;
3760 function Process (N : Node_Id) return Traverse_Result;
3761 -- Check that N does not contain references to local variables or
3762 -- other local entities of Subp.
3768 function Process (N : Node_Id) return Traverse_Result is
3770 if Is_Entity_Name (N)
3771 and then Present (Entity (N))
3772 and then not Is_Formal (Entity (N))
3773 and then Enclosing_Subprogram (Entity (N)) = Subp
3775 Error_Msg_Node_1 := Entity (N);
3777 ("attribute % cannot refer to local variable&", N);
3783 procedure Check_No_Local is new Traverse_Proc;
3785 -- Start of processing for Check_Local
3790 if In_Parameter_Specification (P) then
3792 -- We have additional restrictions on using 'Old in parameter
3795 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3797 -- Check that there is no reference to the enclosing
3798 -- subprogram local variables. Otherwise, we might end up
3799 -- being called from the enclosing subprogram and thus using
3800 -- 'Old on a local variable which is not defined at entry
3803 Subp := Enclosing_Subprogram (Current_Subprogram);
3807 -- We must prevent default expression of library-level
3808 -- subprogram from using 'Old, as the subprogram may be
3809 -- used in elaboration code for which there is no enclosing
3813 ("attribute % can only appear within subprogram", N);
3822 when Attribute_Output =>
3824 Check_Stream_Attribute (TSS_Stream_Output);
3825 Set_Etype (N, Standard_Void_Type);
3826 Resolve (N, Standard_Void_Type);
3832 when Attribute_Partition_ID => Partition_Id :
3836 if P_Type /= Any_Type then
3837 if not Is_Library_Level_Entity (Entity (P)) then
3839 ("prefix of % attribute must be library-level entity");
3841 -- The defining entity of prefix should not be declared inside a
3842 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3844 elsif Is_Entity_Name (P)
3845 and then Is_Pure (Entity (P))
3847 Error_Attr_P ("prefix of% attribute must not be declared pure");
3851 Set_Etype (N, Universal_Integer);
3854 -------------------------
3855 -- Passed_By_Reference --
3856 -------------------------
3858 when Attribute_Passed_By_Reference =>
3861 Set_Etype (N, Standard_Boolean);
3867 when Attribute_Pool_Address =>
3869 Set_Etype (N, RTE (RE_Address));
3875 when Attribute_Pos =>
3876 Check_Discrete_Type;
3879 if Is_Boolean_Type (P_Type) then
3880 Error_Msg_Name_1 := Aname;
3881 Error_Msg_Name_2 := Chars (P_Type);
3882 Check_Formal_Restriction
3883 ("attribute% is not allowed for type%", P);
3886 Resolve (E1, P_Base_Type);
3887 Set_Etype (N, Universal_Integer);
3893 when Attribute_Position =>
3895 Set_Etype (N, Universal_Integer);
3901 when Attribute_Pred =>
3905 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
3906 Error_Msg_Name_1 := Aname;
3907 Error_Msg_Name_2 := Chars (P_Type);
3908 Check_Formal_Restriction
3909 ("attribute% is not allowed for type%", P);
3912 Resolve (E1, P_Base_Type);
3913 Set_Etype (N, P_Base_Type);
3915 -- Nothing to do for real type case
3917 if Is_Real_Type (P_Type) then
3920 -- If not modular type, test for overflow check required
3923 if not Is_Modular_Integer_Type (P_Type)
3924 and then not Range_Checks_Suppressed (P_Base_Type)
3926 Enable_Range_Check (E1);
3934 -- Ada 2005 (AI-327): Dynamic ceiling priorities
3936 when Attribute_Priority =>
3937 if Ada_Version < Ada_2005 then
3938 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
3943 -- The prefix must be a protected object (AARM D.5.2 (2/2))
3947 if Is_Protected_Type (Etype (P))
3948 or else (Is_Access_Type (Etype (P))
3949 and then Is_Protected_Type (Designated_Type (Etype (P))))
3951 Resolve (P, Etype (P));
3953 Error_Attr_P ("prefix of % attribute must be a protected object");
3956 Set_Etype (N, Standard_Integer);
3958 -- Must be called from within a protected procedure or entry of the
3959 -- protected object.
3966 while S /= Etype (P)
3967 and then S /= Standard_Standard
3972 if S = Standard_Standard then
3973 Error_Attr ("the attribute % is only allowed inside protected "
3978 Validate_Non_Static_Attribute_Function_Call;
3984 when Attribute_Range =>
3985 Check_Array_Or_Scalar_Type;
3986 Bad_Attribute_For_Predicate;
3988 if Ada_Version = Ada_83
3989 and then Is_Scalar_Type (P_Type)
3990 and then Comes_From_Source (N)
3993 ("(Ada 83) % attribute not allowed for scalar type", P);
4000 when Attribute_Result => Result : declare
4002 -- The enclosing scope, excluding loops for quantified expressions
4005 -- During analysis, CS is the postcondition subprogram and PS the
4006 -- source subprogram to which the postcondition applies. During
4007 -- pre-analysis, CS is the scope of the subprogram declaration.
4010 -- Find enclosing scopes, excluding loops
4012 CS := Current_Scope;
4013 while Ekind (CS) = E_Loop loop
4019 -- If the enclosing subprogram is always inlined, the enclosing
4020 -- postcondition will not be propagated to the expanded call.
4022 if not In_Spec_Expression
4023 and then Has_Pragma_Inline_Always (PS)
4024 and then Warn_On_Redundant_Constructs
4027 ("postconditions on inlined functions not enforced?", N);
4030 -- If we are in the scope of a function and in Spec_Expression mode,
4031 -- this is likely the prescan of the postcondition pragma, and we
4032 -- just set the proper type. If there is an error it will be caught
4033 -- when the real Analyze call is done.
4035 if Ekind (CS) = E_Function
4036 and then In_Spec_Expression
4040 if Chars (CS) /= Chars (P) then
4041 Error_Msg_Name_1 := Name_Result;
4044 ("incorrect prefix for % attribute, expected &", P, CS);
4048 Set_Etype (N, Etype (CS));
4050 -- If several functions with that name are visible,
4051 -- the intended one is the current scope.
4053 if Is_Overloaded (P) then
4055 Set_Is_Overloaded (P, False);
4058 -- Body case, where we must be inside a generated _Postcondition
4059 -- procedure, and the prefix must be on the scope stack, or else
4060 -- the attribute use is definitely misplaced. The condition itself
4061 -- may have generated transient scopes, and is not necessarily the
4065 while Present (CS) and then CS /= Standard_Standard loop
4066 if Chars (CS) = Name_uPostconditions then
4075 if Chars (CS) = Name_uPostconditions
4076 and then Ekind (PS) = E_Function
4080 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
4081 and then Chars (P) = Chars (PS)
4085 -- Within an instance, the prefix designates the local renaming
4086 -- of the original generic.
4088 elsif Is_Entity_Name (P)
4089 and then Ekind (Entity (P)) = E_Function
4090 and then Present (Alias (Entity (P)))
4091 and then Chars (Alias (Entity (P))) = Chars (PS)
4097 ("incorrect prefix for % attribute, expected &", P, PS);
4101 Rewrite (N, Make_Identifier (Sloc (N), Name_uResult));
4102 Analyze_And_Resolve (N, Etype (PS));
4106 ("% attribute can only appear" &
4107 " in function Postcondition pragma", P);
4116 when Attribute_Range_Length =>
4118 Check_Discrete_Type;
4119 Set_Etype (N, Universal_Integer);
4125 when Attribute_Read =>
4127 Check_Stream_Attribute (TSS_Stream_Read);
4128 Set_Etype (N, Standard_Void_Type);
4129 Resolve (N, Standard_Void_Type);
4130 Note_Possible_Modification (E2, Sure => True);
4136 when Attribute_Ref =>
4140 if Nkind (P) /= N_Expanded_Name
4141 or else not Is_RTE (P_Type, RE_Address)
4143 Error_Attr_P ("prefix of % attribute must be System.Address");
4146 Analyze_And_Resolve (E1, Any_Integer);
4147 Set_Etype (N, RTE (RE_Address));
4153 when Attribute_Remainder =>
4154 Check_Floating_Point_Type_2;
4155 Set_Etype (N, P_Base_Type);
4156 Resolve (E1, P_Base_Type);
4157 Resolve (E2, P_Base_Type);
4163 when Attribute_Round =>
4165 Check_Decimal_Fixed_Point_Type;
4166 Set_Etype (N, P_Base_Type);
4168 -- Because the context is universal_real (3.5.10(12)) it is a legal
4169 -- context for a universal fixed expression. This is the only
4170 -- attribute whose functional description involves U_R.
4172 if Etype (E1) = Universal_Fixed then
4174 Conv : constant Node_Id := Make_Type_Conversion (Loc,
4175 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
4176 Expression => Relocate_Node (E1));
4184 Resolve (E1, Any_Real);
4190 when Attribute_Rounding =>
4191 Check_Floating_Point_Type_1;
4192 Set_Etype (N, P_Base_Type);
4193 Resolve (E1, P_Base_Type);
4199 when Attribute_Safe_Emax =>
4200 Check_Floating_Point_Type_0;
4201 Set_Etype (N, Universal_Integer);
4207 when Attribute_Safe_First =>
4208 Check_Floating_Point_Type_0;
4209 Set_Etype (N, Universal_Real);
4215 when Attribute_Safe_Large =>
4218 Set_Etype (N, Universal_Real);
4224 when Attribute_Safe_Last =>
4225 Check_Floating_Point_Type_0;
4226 Set_Etype (N, Universal_Real);
4232 when Attribute_Safe_Small =>
4235 Set_Etype (N, Universal_Real);
4241 when Attribute_Scale =>
4243 Check_Decimal_Fixed_Point_Type;
4244 Set_Etype (N, Universal_Integer);
4250 when Attribute_Scaling =>
4251 Check_Floating_Point_Type_2;
4252 Set_Etype (N, P_Base_Type);
4253 Resolve (E1, P_Base_Type);
4259 when Attribute_Signed_Zeros =>
4260 Check_Floating_Point_Type_0;
4261 Set_Etype (N, Standard_Boolean);
4267 when Attribute_Size | Attribute_VADS_Size => Size :
4271 -- If prefix is parameterless function call, rewrite and resolve
4274 if Is_Entity_Name (P)
4275 and then Ekind (Entity (P)) = E_Function
4279 -- Similar processing for a protected function call
4281 elsif Nkind (P) = N_Selected_Component
4282 and then Ekind (Entity (Selector_Name (P))) = E_Function
4287 if Is_Object_Reference (P) then
4288 Check_Object_Reference (P);
4290 elsif Is_Entity_Name (P)
4291 and then (Is_Type (Entity (P))
4292 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4296 elsif Nkind (P) = N_Type_Conversion
4297 and then not Comes_From_Source (P)
4302 Error_Attr_P ("invalid prefix for % attribute");
4305 Check_Not_Incomplete_Type;
4307 Set_Etype (N, Universal_Integer);
4314 when Attribute_Small =>
4317 Set_Etype (N, Universal_Real);
4323 when Attribute_Storage_Pool => Storage_Pool :
4327 if Is_Access_Type (P_Type) then
4328 if Ekind (P_Type) = E_Access_Subprogram_Type then
4330 ("cannot use % attribute for access-to-subprogram type");
4333 -- Set appropriate entity
4335 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4336 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4338 Set_Entity (N, RTE (RE_Global_Pool_Object));
4341 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4343 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4344 -- Storage_Pool since this attribute is not defined for such
4345 -- types (RM E.2.3(22)).
4347 Validate_Remote_Access_To_Class_Wide_Type (N);
4350 Error_Attr_P ("prefix of % attribute must be access type");
4358 when Attribute_Storage_Size => Storage_Size :
4362 if Is_Task_Type (P_Type) then
4363 Set_Etype (N, Universal_Integer);
4365 -- Use with tasks is an obsolescent feature
4367 Check_Restriction (No_Obsolescent_Features, P);
4369 elsif Is_Access_Type (P_Type) then
4370 if Ekind (P_Type) = E_Access_Subprogram_Type then
4372 ("cannot use % attribute for access-to-subprogram type");
4375 if Is_Entity_Name (P)
4376 and then Is_Type (Entity (P))
4379 Set_Etype (N, Universal_Integer);
4381 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4382 -- Storage_Size since this attribute is not defined for
4383 -- such types (RM E.2.3(22)).
4385 Validate_Remote_Access_To_Class_Wide_Type (N);
4387 -- The prefix is allowed to be an implicit dereference
4388 -- of an access value designating a task.
4392 Set_Etype (N, Universal_Integer);
4396 Error_Attr_P ("prefix of % attribute must be access or task type");
4404 when Attribute_Storage_Unit =>
4405 Standard_Attribute (Ttypes.System_Storage_Unit);
4411 when Attribute_Stream_Size =>
4415 if Is_Entity_Name (P)
4416 and then Is_Elementary_Type (Entity (P))
4418 Set_Etype (N, Universal_Integer);
4420 Error_Attr_P ("invalid prefix for % attribute");
4427 when Attribute_Stub_Type =>
4431 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4433 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4436 ("prefix of% attribute must be remote access to classwide");
4443 when Attribute_Succ =>
4447 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
4448 Error_Msg_Name_1 := Aname;
4449 Error_Msg_Name_2 := Chars (P_Type);
4450 Check_Formal_Restriction
4451 ("attribute% is not allowed for type%", P);
4454 Resolve (E1, P_Base_Type);
4455 Set_Etype (N, P_Base_Type);
4457 -- Nothing to do for real type case
4459 if Is_Real_Type (P_Type) then
4462 -- If not modular type, test for overflow check required
4465 if not Is_Modular_Integer_Type (P_Type)
4466 and then not Range_Checks_Suppressed (P_Base_Type)
4468 Enable_Range_Check (E1);
4476 when Attribute_Tag => Tag :
4481 if not Is_Tagged_Type (P_Type) then
4482 Error_Attr_P ("prefix of % attribute must be tagged");
4484 -- Next test does not apply to generated code
4485 -- why not, and what does the illegal reference mean???
4487 elsif Is_Object_Reference (P)
4488 and then not Is_Class_Wide_Type (P_Type)
4489 and then Comes_From_Source (N)
4492 ("% attribute can only be applied to objects " &
4493 "of class - wide type");
4496 -- The prefix cannot be an incomplete type. However, references
4497 -- to 'Tag can be generated when expanding interface conversions,
4498 -- and this is legal.
4500 if Comes_From_Source (N) then
4501 Check_Not_Incomplete_Type;
4504 -- Set appropriate type
4506 Set_Etype (N, RTE (RE_Tag));
4513 when Attribute_Target_Name => Target_Name : declare
4514 TN : constant String := Sdefault.Target_Name.all;
4518 Check_Standard_Prefix;
4522 if TN (TL) = '/' or else TN (TL) = '\' then
4527 Make_String_Literal (Loc,
4528 Strval => TN (TN'First .. TL)));
4529 Analyze_And_Resolve (N, Standard_String);
4536 when Attribute_Terminated =>
4538 Set_Etype (N, Standard_Boolean);
4545 when Attribute_To_Address =>
4549 if Nkind (P) /= N_Identifier
4550 or else Chars (P) /= Name_System
4552 Error_Attr_P ("prefix of % attribute must be System");
4555 Generate_Reference (RTE (RE_Address), P);
4556 Analyze_And_Resolve (E1, Any_Integer);
4557 Set_Etype (N, RTE (RE_Address));
4563 when Attribute_To_Any =>
4565 Check_PolyORB_Attribute;
4566 Set_Etype (N, RTE (RE_Any));
4572 when Attribute_Truncation =>
4573 Check_Floating_Point_Type_1;
4574 Resolve (E1, P_Base_Type);
4575 Set_Etype (N, P_Base_Type);
4581 when Attribute_Type_Class =>
4584 Check_Not_Incomplete_Type;
4585 Set_Etype (N, RTE (RE_Type_Class));
4591 when Attribute_TypeCode =>
4593 Check_PolyORB_Attribute;
4594 Set_Etype (N, RTE (RE_TypeCode));
4600 when Attribute_Type_Key =>
4604 -- This processing belongs in Eval_Attribute ???
4607 function Type_Key return String_Id;
4608 -- A very preliminary implementation. For now, a signature
4609 -- consists of only the type name. This is clearly incomplete
4610 -- (e.g., adding a new field to a record type should change the
4611 -- type's Type_Key attribute).
4617 function Type_Key return String_Id is
4618 Full_Name : constant String_Id :=
4619 Fully_Qualified_Name_String (Entity (P));
4622 -- Copy all characters in Full_Name but the trailing NUL
4625 for J in 1 .. String_Length (Full_Name) - 1 loop
4626 Store_String_Char (Get_String_Char (Full_Name, Int (J)));
4629 Store_String_Chars ("'Type_Key");
4634 Rewrite (N, Make_String_Literal (Loc, Type_Key));
4637 Analyze_And_Resolve (N, Standard_String);
4643 when Attribute_UET_Address =>
4645 Check_Unit_Name (P);
4646 Set_Etype (N, RTE (RE_Address));
4648 -----------------------
4649 -- Unbiased_Rounding --
4650 -----------------------
4652 when Attribute_Unbiased_Rounding =>
4653 Check_Floating_Point_Type_1;
4654 Set_Etype (N, P_Base_Type);
4655 Resolve (E1, P_Base_Type);
4657 ----------------------
4658 -- Unchecked_Access --
4659 ----------------------
4661 when Attribute_Unchecked_Access =>
4662 if Comes_From_Source (N) then
4663 Check_Restriction (No_Unchecked_Access, N);
4666 Analyze_Access_Attribute;
4668 -------------------------
4669 -- Unconstrained_Array --
4670 -------------------------
4672 when Attribute_Unconstrained_Array =>
4675 Check_Not_Incomplete_Type;
4676 Set_Etype (N, Standard_Boolean);
4678 ------------------------------
4679 -- Universal_Literal_String --
4680 ------------------------------
4682 -- This is a GNAT specific attribute whose prefix must be a named
4683 -- number where the expression is either a single numeric literal,
4684 -- or a numeric literal immediately preceded by a minus sign. The
4685 -- result is equivalent to a string literal containing the text of
4686 -- the literal as it appeared in the source program with a possible
4687 -- leading minus sign.
4689 when Attribute_Universal_Literal_String => Universal_Literal_String :
4693 if not Is_Entity_Name (P)
4694 or else Ekind (Entity (P)) not in Named_Kind
4696 Error_Attr_P ("prefix for % attribute must be named number");
4703 Src : Source_Buffer_Ptr;
4706 Expr := Original_Node (Expression (Parent (Entity (P))));
4708 if Nkind (Expr) = N_Op_Minus then
4710 Expr := Original_Node (Right_Opnd (Expr));
4715 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4717 ("named number for % attribute must be simple literal", N);
4720 -- Build string literal corresponding to source literal text
4725 Store_String_Char (Get_Char_Code ('-'));
4729 Src := Source_Text (Get_Source_File_Index (S));
4731 while Src (S) /= ';' and then Src (S) /= ' ' loop
4732 Store_String_Char (Get_Char_Code (Src (S)));
4736 -- Now we rewrite the attribute with the string literal
4739 Make_String_Literal (Loc, End_String));
4743 end Universal_Literal_String;
4745 -------------------------
4746 -- Unrestricted_Access --
4747 -------------------------
4749 -- This is a GNAT specific attribute which is like Access except that
4750 -- all scope checks and checks for aliased views are omitted.
4752 when Attribute_Unrestricted_Access =>
4753 if Comes_From_Source (N) then
4754 Check_Restriction (No_Unchecked_Access, N);
4757 if Is_Entity_Name (P) then
4758 Set_Address_Taken (Entity (P));
4761 Analyze_Access_Attribute;
4767 when Attribute_Val => Val : declare
4770 Check_Discrete_Type;
4772 if Is_Boolean_Type (P_Type) then
4773 Error_Msg_Name_1 := Aname;
4774 Error_Msg_Name_2 := Chars (P_Type);
4775 Check_Formal_Restriction
4776 ("attribute% is not allowed for type%", P);
4779 Resolve (E1, Any_Integer);
4780 Set_Etype (N, P_Base_Type);
4782 -- Note, we need a range check in general, but we wait for the
4783 -- Resolve call to do this, since we want to let Eval_Attribute
4784 -- have a chance to find an static illegality first!
4791 when Attribute_Valid =>
4794 -- Ignore check for object if we have a 'Valid reference generated
4795 -- by the expanded code, since in some cases valid checks can occur
4796 -- on items that are names, but are not objects (e.g. attributes).
4798 if Comes_From_Source (N) then
4799 Check_Object_Reference (P);
4802 if not Is_Scalar_Type (P_Type) then
4803 Error_Attr_P ("object for % attribute must be of scalar type");
4806 Set_Etype (N, Standard_Boolean);
4812 when Attribute_Value => Value :
4814 Check_Formal_Restriction_On_Attribute;
4818 -- Case of enumeration type
4820 if Is_Enumeration_Type (P_Type) then
4821 Check_Restriction (No_Enumeration_Maps, N);
4823 -- Mark all enumeration literals as referenced, since the use of
4824 -- the Value attribute can implicitly reference any of the
4825 -- literals of the enumeration base type.
4828 Ent : Entity_Id := First_Literal (P_Base_Type);
4830 while Present (Ent) loop
4831 Set_Referenced (Ent);
4837 -- Set Etype before resolving expression because expansion of
4838 -- expression may require enclosing type. Note that the type
4839 -- returned by 'Value is the base type of the prefix type.
4841 Set_Etype (N, P_Base_Type);
4842 Validate_Non_Static_Attribute_Function_Call;
4849 when Attribute_Value_Size =>
4852 Check_Not_Incomplete_Type;
4853 Set_Etype (N, Universal_Integer);
4859 when Attribute_Version =>
4862 Set_Etype (N, RTE (RE_Version_String));
4868 when Attribute_Wchar_T_Size =>
4869 Standard_Attribute (Interfaces_Wchar_T_Size);
4875 when Attribute_Wide_Image => Wide_Image :
4877 Check_Formal_Restriction_On_Attribute;
4879 Set_Etype (N, Standard_Wide_String);
4881 Resolve (E1, P_Base_Type);
4882 Validate_Non_Static_Attribute_Function_Call;
4885 ---------------------
4886 -- Wide_Wide_Image --
4887 ---------------------
4889 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
4892 Set_Etype (N, Standard_Wide_Wide_String);
4894 Resolve (E1, P_Base_Type);
4895 Validate_Non_Static_Attribute_Function_Call;
4896 end Wide_Wide_Image;
4902 when Attribute_Wide_Value => Wide_Value :
4904 Check_Formal_Restriction_On_Attribute;
4908 -- Set Etype before resolving expression because expansion
4909 -- of expression may require enclosing type.
4911 Set_Etype (N, P_Type);
4912 Validate_Non_Static_Attribute_Function_Call;
4915 ---------------------
4916 -- Wide_Wide_Value --
4917 ---------------------
4919 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
4924 -- Set Etype before resolving expression because expansion
4925 -- of expression may require enclosing type.
4927 Set_Etype (N, P_Type);
4928 Validate_Non_Static_Attribute_Function_Call;
4929 end Wide_Wide_Value;
4931 ---------------------
4932 -- Wide_Wide_Width --
4933 ---------------------
4935 when Attribute_Wide_Wide_Width =>
4938 Set_Etype (N, Universal_Integer);
4944 when Attribute_Wide_Width =>
4945 Check_Formal_Restriction_On_Attribute;
4948 Set_Etype (N, Universal_Integer);
4954 when Attribute_Width =>
4955 Check_Formal_Restriction_On_Attribute;
4958 Set_Etype (N, Universal_Integer);
4964 when Attribute_Word_Size =>
4965 Standard_Attribute (System_Word_Size);
4971 when Attribute_Write =>
4973 Check_Stream_Attribute (TSS_Stream_Write);
4974 Set_Etype (N, Standard_Void_Type);
4975 Resolve (N, Standard_Void_Type);
4979 -- All errors raise Bad_Attribute, so that we get out before any further
4980 -- damage occurs when an error is detected (for example, if we check for
4981 -- one attribute expression, and the check succeeds, we want to be able
4982 -- to proceed securely assuming that an expression is in fact present.
4984 -- Note: we set the attribute analyzed in this case to prevent any
4985 -- attempt at reanalysis which could generate spurious error msgs.
4988 when Bad_Attribute =>
4990 Set_Etype (N, Any_Type);
4992 end Analyze_Attribute;
4994 --------------------
4995 -- Eval_Attribute --
4996 --------------------
4998 procedure Eval_Attribute (N : Node_Id) is
4999 Loc : constant Source_Ptr := Sloc (N);
5000 Aname : constant Name_Id := Attribute_Name (N);
5001 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
5002 P : constant Node_Id := Prefix (N);
5004 C_Type : constant Entity_Id := Etype (N);
5005 -- The type imposed by the context
5008 -- First expression, or Empty if none
5011 -- Second expression, or Empty if none
5013 P_Entity : Entity_Id;
5014 -- Entity denoted by prefix
5017 -- The type of the prefix
5019 P_Base_Type : Entity_Id;
5020 -- The base type of the prefix type
5022 P_Root_Type : Entity_Id;
5023 -- The root type of the prefix type
5026 -- True if the result is Static. This is set by the general processing
5027 -- to true if the prefix is static, and all expressions are static. It
5028 -- can be reset as processing continues for particular attributes
5030 Lo_Bound, Hi_Bound : Node_Id;
5031 -- Expressions for low and high bounds of type or array index referenced
5032 -- by First, Last, or Length attribute for array, set by Set_Bounds.
5035 -- Constraint error node used if we have an attribute reference has
5036 -- an argument that raises a constraint error. In this case we replace
5037 -- the attribute with a raise constraint_error node. This is important
5038 -- processing, since otherwise gigi might see an attribute which it is
5039 -- unprepared to deal with.
5041 procedure Check_Concurrent_Discriminant (Bound : Node_Id);
5042 -- If Bound is a reference to a discriminant of a task or protected type
5043 -- occurring within the object's body, rewrite attribute reference into
5044 -- a reference to the corresponding discriminal. Use for the expansion
5045 -- of checks against bounds of entry family index subtypes.
5047 procedure Check_Expressions;
5048 -- In case where the attribute is not foldable, the expressions, if
5049 -- any, of the attribute, are in a non-static context. This procedure
5050 -- performs the required additional checks.
5052 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
5053 -- Determines if the given type has compile time known bounds. Note
5054 -- that we enter the case statement even in cases where the prefix
5055 -- type does NOT have known bounds, so it is important to guard any
5056 -- attempt to evaluate both bounds with a call to this function.
5058 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
5059 -- This procedure is called when the attribute N has a non-static
5060 -- but compile time known value given by Val. It includes the
5061 -- necessary checks for out of range values.
5063 function Fore_Value return Nat;
5064 -- Computes the Fore value for the current attribute prefix, which is
5065 -- known to be a static fixed-point type. Used by Fore and Width.
5067 function Mantissa return Uint;
5068 -- Returns the Mantissa value for the prefix type
5070 procedure Set_Bounds;
5071 -- Used for First, Last and Length attributes applied to an array or
5072 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
5073 -- and high bound expressions for the index referenced by the attribute
5074 -- designator (i.e. the first index if no expression is present, and
5075 -- the N'th index if the value N is present as an expression). Also
5076 -- used for First and Last of scalar types. Static is reset to False
5077 -- if the type or index type is not statically constrained.
5079 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
5080 -- Verify that the prefix of a potentially static array attribute
5081 -- satisfies the conditions of 4.9 (14).
5083 -----------------------------------
5084 -- Check_Concurrent_Discriminant --
5085 -----------------------------------
5087 procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
5089 -- The concurrent (task or protected) type
5092 if Nkind (Bound) = N_Identifier
5093 and then Ekind (Entity (Bound)) = E_Discriminant
5094 and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
5096 Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
5098 if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
5100 -- Find discriminant of original concurrent type, and use
5101 -- its current discriminal, which is the renaming within
5102 -- the task/protected body.
5106 (Find_Body_Discriminal (Entity (Bound)), Loc));
5109 end Check_Concurrent_Discriminant;
5111 -----------------------
5112 -- Check_Expressions --
5113 -----------------------
5115 procedure Check_Expressions is
5119 while Present (E) loop
5120 Check_Non_Static_Context (E);
5123 end Check_Expressions;
5125 ----------------------------------
5126 -- Compile_Time_Known_Attribute --
5127 ----------------------------------
5129 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
5130 T : constant Entity_Id := Etype (N);
5133 Fold_Uint (N, Val, False);
5135 -- Check that result is in bounds of the type if it is static
5137 if Is_In_Range (N, T, Assume_Valid => False) then
5140 elsif Is_Out_Of_Range (N, T) then
5141 Apply_Compile_Time_Constraint_Error
5142 (N, "value not in range of}?", CE_Range_Check_Failed);
5144 elsif not Range_Checks_Suppressed (T) then
5145 Enable_Range_Check (N);
5148 Set_Do_Range_Check (N, False);
5150 end Compile_Time_Known_Attribute;
5152 -------------------------------
5153 -- Compile_Time_Known_Bounds --
5154 -------------------------------
5156 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
5159 Compile_Time_Known_Value (Type_Low_Bound (Typ))
5161 Compile_Time_Known_Value (Type_High_Bound (Typ));
5162 end Compile_Time_Known_Bounds;
5168 -- Note that the Fore calculation is based on the actual values
5169 -- of the bounds, and does not take into account possible rounding.
5171 function Fore_Value return Nat is
5172 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
5173 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
5174 Small : constant Ureal := Small_Value (P_Type);
5175 Lo_Real : constant Ureal := Lo * Small;
5176 Hi_Real : constant Ureal := Hi * Small;
5181 -- Bounds are given in terms of small units, so first compute
5182 -- proper values as reals.
5184 T := UR_Max (abs Lo_Real, abs Hi_Real);
5187 -- Loop to compute proper value if more than one digit required
5189 while T >= Ureal_10 loop
5201 -- Table of mantissa values accessed by function Computed using
5204 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5206 -- where D is T'Digits (RM83 3.5.7)
5208 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5250 function Mantissa return Uint is
5253 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5260 procedure Set_Bounds is
5266 -- For a string literal subtype, we have to construct the bounds.
5267 -- Valid Ada code never applies attributes to string literals, but
5268 -- it is convenient to allow the expander to generate attribute
5269 -- references of this type (e.g. First and Last applied to a string
5272 -- Note that the whole point of the E_String_Literal_Subtype is to
5273 -- avoid this construction of bounds, but the cases in which we
5274 -- have to materialize them are rare enough that we don't worry!
5276 -- The low bound is simply the low bound of the base type. The
5277 -- high bound is computed from the length of the string and this
5280 if Ekind (P_Type) = E_String_Literal_Subtype then
5281 Ityp := Etype (First_Index (Base_Type (P_Type)));
5282 Lo_Bound := Type_Low_Bound (Ityp);
5285 Make_Integer_Literal (Sloc (P),
5287 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5289 Set_Parent (Hi_Bound, P);
5290 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5293 -- For non-array case, just get bounds of scalar type
5295 elsif Is_Scalar_Type (P_Type) then
5298 -- For a fixed-point type, we must freeze to get the attributes
5299 -- of the fixed-point type set now so we can reference them.
5301 if Is_Fixed_Point_Type (P_Type)
5302 and then not Is_Frozen (Base_Type (P_Type))
5303 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5304 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5306 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5309 -- For array case, get type of proper index
5315 Ndim := UI_To_Int (Expr_Value (E1));
5318 Indx := First_Index (P_Type);
5319 for J in 1 .. Ndim - 1 loop
5323 -- If no index type, get out (some other error occurred, and
5324 -- we don't have enough information to complete the job!)
5332 Ityp := Etype (Indx);
5335 -- A discrete range in an index constraint is allowed to be a
5336 -- subtype indication. This is syntactically a pain, but should
5337 -- not propagate to the entity for the corresponding index subtype.
5338 -- After checking that the subtype indication is legal, the range
5339 -- of the subtype indication should be transfered to the entity.
5340 -- The attributes for the bounds should remain the simple retrievals
5341 -- that they are now.
5343 Lo_Bound := Type_Low_Bound (Ityp);
5344 Hi_Bound := Type_High_Bound (Ityp);
5346 if not Is_Static_Subtype (Ityp) then
5351 -------------------------------
5352 -- Statically_Denotes_Entity --
5353 -------------------------------
5355 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5359 if not Is_Entity_Name (N) then
5366 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5367 or else Statically_Denotes_Entity (Renamed_Object (E));
5368 end Statically_Denotes_Entity;
5370 -- Start of processing for Eval_Attribute
5373 -- No folding in spec expression that comes from source where the prefix
5374 -- is an unfrozen entity. This avoids premature folding in cases like:
5376 -- procedure DefExprAnal is
5377 -- type R is new Integer;
5378 -- procedure P (Arg : Integer := R'Size);
5379 -- for R'Size use 64;
5380 -- procedure P (Arg : Integer := R'Size) is
5382 -- Put_Line (Arg'Img);
5388 -- which should print 64 rather than 32. The exclusion of non-source
5389 -- constructs from this test comes from some internal usage in packed
5390 -- arrays, which otherwise fails, could use more analysis perhaps???
5392 -- We do however go ahead with generic actual types, otherwise we get
5393 -- some regressions, probably these types should be frozen anyway???
5395 if In_Spec_Expression
5396 and then Comes_From_Source (N)
5397 and then not (Is_Entity_Name (P)
5399 (Is_Frozen (Entity (P))
5400 or else (Is_Type (Entity (P))
5402 Is_Generic_Actual_Type (Entity (P)))))
5407 -- Acquire first two expressions (at the moment, no attributes take more
5408 -- than two expressions in any case).
5410 if Present (Expressions (N)) then
5411 E1 := First (Expressions (N));
5418 -- Special processing for Enabled attribute. This attribute has a very
5419 -- special prefix, and the easiest way to avoid lots of special checks
5420 -- to protect this special prefix from causing trouble is to deal with
5421 -- this attribute immediately and be done with it.
5423 if Id = Attribute_Enabled then
5425 -- We skip evaluation if the expander is not active. This is not just
5426 -- an optimization. It is of key importance that we not rewrite the
5427 -- attribute in a generic template, since we want to pick up the
5428 -- setting of the check in the instance, and testing expander active
5429 -- is as easy way of doing this as any.
5431 if Expander_Active then
5433 C : constant Check_Id := Get_Check_Id (Chars (P));
5438 if C in Predefined_Check_Id then
5439 R := Scope_Suppress (C);
5441 R := Is_Check_Suppressed (Empty, C);
5445 R := Is_Check_Suppressed (Entity (E1), C);
5449 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5451 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5459 -- Special processing for cases where the prefix is an object. For
5460 -- this purpose, a string literal counts as an object (attributes
5461 -- of string literals can only appear in generated code).
5463 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5465 -- For Component_Size, the prefix is an array object, and we apply
5466 -- the attribute to the type of the object. This is allowed for
5467 -- both unconstrained and constrained arrays, since the bounds
5468 -- have no influence on the value of this attribute.
5470 if Id = Attribute_Component_Size then
5471 P_Entity := Etype (P);
5473 -- For First and Last, the prefix is an array object, and we apply
5474 -- the attribute to the type of the array, but we need a constrained
5475 -- type for this, so we use the actual subtype if available.
5477 elsif Id = Attribute_First
5481 Id = Attribute_Length
5484 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5487 if Present (AS) and then Is_Constrained (AS) then
5490 -- If we have an unconstrained type we cannot fold
5498 -- For Size, give size of object if available, otherwise we
5499 -- cannot fold Size.
5501 elsif Id = Attribute_Size then
5502 if Is_Entity_Name (P)
5503 and then Known_Esize (Entity (P))
5505 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5513 -- For Alignment, give size of object if available, otherwise we
5514 -- cannot fold Alignment.
5516 elsif Id = Attribute_Alignment then
5517 if Is_Entity_Name (P)
5518 and then Known_Alignment (Entity (P))
5520 Fold_Uint (N, Alignment (Entity (P)), False);
5528 -- No other attributes for objects are folded
5535 -- Cases where P is not an object. Cannot do anything if P is
5536 -- not the name of an entity.
5538 elsif not Is_Entity_Name (P) then
5542 -- Otherwise get prefix entity
5545 P_Entity := Entity (P);
5548 -- At this stage P_Entity is the entity to which the attribute
5549 -- is to be applied. This is usually simply the entity of the
5550 -- prefix, except in some cases of attributes for objects, where
5551 -- as described above, we apply the attribute to the object type.
5553 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5554 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5555 -- Note we allow non-static non-generic types at this stage as further
5558 if Is_Type (P_Entity)
5559 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5560 and then (not Is_Generic_Type (P_Entity))
5564 -- Second foldable possibility is an array object (RM 4.9(8))
5566 elsif (Ekind (P_Entity) = E_Variable
5568 Ekind (P_Entity) = E_Constant)
5569 and then Is_Array_Type (Etype (P_Entity))
5570 and then (not Is_Generic_Type (Etype (P_Entity)))
5572 P_Type := Etype (P_Entity);
5574 -- If the entity is an array constant with an unconstrained nominal
5575 -- subtype then get the type from the initial value. If the value has
5576 -- been expanded into assignments, there is no expression and the
5577 -- attribute reference remains dynamic.
5579 -- We could do better here and retrieve the type ???
5581 if Ekind (P_Entity) = E_Constant
5582 and then not Is_Constrained (P_Type)
5584 if No (Constant_Value (P_Entity)) then
5587 P_Type := Etype (Constant_Value (P_Entity));
5591 -- Definite must be folded if the prefix is not a generic type,
5592 -- that is to say if we are within an instantiation. Same processing
5593 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5594 -- Has_Tagged_Value, and Unconstrained_Array.
5596 elsif (Id = Attribute_Definite
5598 Id = Attribute_Has_Access_Values
5600 Id = Attribute_Has_Discriminants
5602 Id = Attribute_Has_Tagged_Values
5604 Id = Attribute_Type_Class
5606 Id = Attribute_Unconstrained_Array
5608 Id = Attribute_Max_Alignment_For_Allocation)
5609 and then not Is_Generic_Type (P_Entity)
5613 -- We can fold 'Size applied to a type if the size is known (as happens
5614 -- for a size from an attribute definition clause). At this stage, this
5615 -- can happen only for types (e.g. record types) for which the size is
5616 -- always non-static. We exclude generic types from consideration (since
5617 -- they have bogus sizes set within templates).
5619 elsif Id = Attribute_Size
5620 and then Is_Type (P_Entity)
5621 and then (not Is_Generic_Type (P_Entity))
5622 and then Known_Static_RM_Size (P_Entity)
5624 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5627 -- We can fold 'Alignment applied to a type if the alignment is known
5628 -- (as happens for an alignment from an attribute definition clause).
5629 -- At this stage, this can happen only for types (e.g. record
5630 -- types) for which the size is always non-static. We exclude
5631 -- generic types from consideration (since they have bogus
5632 -- sizes set within templates).
5634 elsif Id = Attribute_Alignment
5635 and then Is_Type (P_Entity)
5636 and then (not Is_Generic_Type (P_Entity))
5637 and then Known_Alignment (P_Entity)
5639 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5642 -- If this is an access attribute that is known to fail accessibility
5643 -- check, rewrite accordingly.
5645 elsif Attribute_Name (N) = Name_Access
5646 and then Raises_Constraint_Error (N)
5649 Make_Raise_Program_Error (Loc,
5650 Reason => PE_Accessibility_Check_Failed));
5651 Set_Etype (N, C_Type);
5654 -- No other cases are foldable (they certainly aren't static, and at
5655 -- the moment we don't try to fold any cases other than these three).
5662 -- If either attribute or the prefix is Any_Type, then propagate
5663 -- Any_Type to the result and don't do anything else at all.
5665 if P_Type = Any_Type
5666 or else (Present (E1) and then Etype (E1) = Any_Type)
5667 or else (Present (E2) and then Etype (E2) = Any_Type)
5669 Set_Etype (N, Any_Type);
5673 -- Scalar subtype case. We have not yet enforced the static requirement
5674 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5675 -- of non-static attribute references (e.g. S'Digits for a non-static
5676 -- floating-point type, which we can compute at compile time).
5678 -- Note: this folding of non-static attributes is not simply a case of
5679 -- optimization. For many of the attributes affected, Gigi cannot handle
5680 -- the attribute and depends on the front end having folded them away.
5682 -- Note: although we don't require staticness at this stage, we do set
5683 -- the Static variable to record the staticness, for easy reference by
5684 -- those attributes where it matters (e.g. Succ and Pred), and also to
5685 -- be used to ensure that non-static folded things are not marked as
5686 -- being static (a check that is done right at the end).
5688 P_Root_Type := Root_Type (P_Type);
5689 P_Base_Type := Base_Type (P_Type);
5691 -- If the root type or base type is generic, then we cannot fold. This
5692 -- test is needed because subtypes of generic types are not always
5693 -- marked as being generic themselves (which seems odd???)
5695 if Is_Generic_Type (P_Root_Type)
5696 or else Is_Generic_Type (P_Base_Type)
5701 if Is_Scalar_Type (P_Type) then
5702 Static := Is_OK_Static_Subtype (P_Type);
5704 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5705 -- since we can't do anything with unconstrained arrays. In addition,
5706 -- only the First, Last and Length attributes are possibly static.
5708 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5709 -- Type_Class, and Unconstrained_Array are again exceptions, because
5710 -- they apply as well to unconstrained types.
5712 -- In addition Component_Size is an exception since it is possibly
5713 -- foldable, even though it is never static, and it does apply to
5714 -- unconstrained arrays. Furthermore, it is essential to fold this
5715 -- in the packed case, since otherwise the value will be incorrect.
5717 elsif Id = Attribute_Definite
5719 Id = Attribute_Has_Access_Values
5721 Id = Attribute_Has_Discriminants
5723 Id = Attribute_Has_Tagged_Values
5725 Id = Attribute_Type_Class
5727 Id = Attribute_Unconstrained_Array
5729 Id = Attribute_Component_Size
5733 elsif Id /= Attribute_Max_Alignment_For_Allocation then
5734 if not Is_Constrained (P_Type)
5735 or else (Id /= Attribute_First and then
5736 Id /= Attribute_Last and then
5737 Id /= Attribute_Length)
5743 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5744 -- scalar case, we hold off on enforcing staticness, since there are
5745 -- cases which we can fold at compile time even though they are not
5746 -- static (e.g. 'Length applied to a static index, even though other
5747 -- non-static indexes make the array type non-static). This is only
5748 -- an optimization, but it falls out essentially free, so why not.
5749 -- Again we compute the variable Static for easy reference later
5750 -- (note that no array attributes are static in Ada 83).
5752 -- We also need to set Static properly for subsequent legality checks
5753 -- which might otherwise accept non-static constants in contexts
5754 -- where they are not legal.
5756 Static := Ada_Version >= Ada_95
5757 and then Statically_Denotes_Entity (P);
5763 N := First_Index (P_Type);
5765 -- The expression is static if the array type is constrained
5766 -- by given bounds, and not by an initial expression. Constant
5767 -- strings are static in any case.
5769 if Root_Type (P_Type) /= Standard_String then
5771 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
5774 while Present (N) loop
5775 Static := Static and then Is_Static_Subtype (Etype (N));
5777 -- If however the index type is generic, or derived from
5778 -- one, attributes cannot be folded.
5780 if Is_Generic_Type (Root_Type (Etype (N)))
5781 and then Id /= Attribute_Component_Size
5791 -- Check any expressions that are present. Note that these expressions,
5792 -- depending on the particular attribute type, are either part of the
5793 -- attribute designator, or they are arguments in a case where the
5794 -- attribute reference returns a function. In the latter case, the
5795 -- rule in (RM 4.9(22)) applies and in particular requires the type
5796 -- of the expressions to be scalar in order for the attribute to be
5797 -- considered to be static.
5804 while Present (E) loop
5806 -- If expression is not static, then the attribute reference
5807 -- result certainly cannot be static.
5809 if not Is_Static_Expression (E) then
5813 -- If the result is not known at compile time, or is not of
5814 -- a scalar type, then the result is definitely not static,
5815 -- so we can quit now.
5817 if not Compile_Time_Known_Value (E)
5818 or else not Is_Scalar_Type (Etype (E))
5820 -- An odd special case, if this is a Pos attribute, this
5821 -- is where we need to apply a range check since it does
5822 -- not get done anywhere else.
5824 if Id = Attribute_Pos then
5825 if Is_Integer_Type (Etype (E)) then
5826 Apply_Range_Check (E, Etype (N));
5833 -- If the expression raises a constraint error, then so does
5834 -- the attribute reference. We keep going in this case because
5835 -- we are still interested in whether the attribute reference
5836 -- is static even if it is not static.
5838 elsif Raises_Constraint_Error (E) then
5839 Set_Raises_Constraint_Error (N);
5845 if Raises_Constraint_Error (Prefix (N)) then
5850 -- Deal with the case of a static attribute reference that raises
5851 -- constraint error. The Raises_Constraint_Error flag will already
5852 -- have been set, and the Static flag shows whether the attribute
5853 -- reference is static. In any case we certainly can't fold such an
5854 -- attribute reference.
5856 -- Note that the rewriting of the attribute node with the constraint
5857 -- error node is essential in this case, because otherwise Gigi might
5858 -- blow up on one of the attributes it never expects to see.
5860 -- The constraint_error node must have the type imposed by the context,
5861 -- to avoid spurious errors in the enclosing expression.
5863 if Raises_Constraint_Error (N) then
5865 Make_Raise_Constraint_Error (Sloc (N),
5866 Reason => CE_Range_Check_Failed);
5867 Set_Etype (CE_Node, Etype (N));
5868 Set_Raises_Constraint_Error (CE_Node);
5870 Rewrite (N, Relocate_Node (CE_Node));
5871 Set_Is_Static_Expression (N, Static);
5875 -- At this point we have a potentially foldable attribute reference.
5876 -- If Static is set, then the attribute reference definitely obeys
5877 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
5878 -- folded. If Static is not set, then the attribute may or may not
5879 -- be foldable, and the individual attribute processing routines
5880 -- test Static as required in cases where it makes a difference.
5882 -- In the case where Static is not set, we do know that all the
5883 -- expressions present are at least known at compile time (we
5884 -- assumed above that if this was not the case, then there was
5885 -- no hope of static evaluation). However, we did not require
5886 -- that the bounds of the prefix type be compile time known,
5887 -- let alone static). That's because there are many attributes
5888 -- that can be computed at compile time on non-static subtypes,
5889 -- even though such references are not static expressions.
5897 when Attribute_Adjacent =>
5900 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5906 when Attribute_Aft =>
5907 Fold_Uint (N, Aft_Value (P_Type), True);
5913 when Attribute_Alignment => Alignment_Block : declare
5914 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5917 -- Fold if alignment is set and not otherwise
5919 if Known_Alignment (P_TypeA) then
5920 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
5922 end Alignment_Block;
5928 -- Can only be folded in No_Ast_Handler case
5930 when Attribute_AST_Entry =>
5931 if not Is_AST_Entry (P_Entity) then
5933 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
5942 -- Bit can never be folded
5944 when Attribute_Bit =>
5951 -- Body_version can never be static
5953 when Attribute_Body_Version =>
5960 when Attribute_Ceiling =>
5962 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
5964 --------------------
5965 -- Component_Size --
5966 --------------------
5968 when Attribute_Component_Size =>
5969 if Known_Static_Component_Size (P_Type) then
5970 Fold_Uint (N, Component_Size (P_Type), False);
5977 when Attribute_Compose =>
5980 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
5987 -- Constrained is never folded for now, there may be cases that
5988 -- could be handled at compile time. To be looked at later.
5990 when Attribute_Constrained =>
5997 when Attribute_Copy_Sign =>
6000 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6006 when Attribute_Delta =>
6007 Fold_Ureal (N, Delta_Value (P_Type), True);
6013 when Attribute_Definite =>
6014 Rewrite (N, New_Occurrence_Of (
6015 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
6016 Analyze_And_Resolve (N, Standard_Boolean);
6022 when Attribute_Denorm =>
6024 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
6030 when Attribute_Digits =>
6031 Fold_Uint (N, Digits_Value (P_Type), True);
6037 when Attribute_Emax =>
6039 -- Ada 83 attribute is defined as (RM83 3.5.8)
6041 -- T'Emax = 4 * T'Mantissa
6043 Fold_Uint (N, 4 * Mantissa, True);
6049 when Attribute_Enum_Rep =>
6051 -- For an enumeration type with a non-standard representation use
6052 -- the Enumeration_Rep field of the proper constant. Note that this
6053 -- will not work for types Character/Wide_[Wide-]Character, since no
6054 -- real entities are created for the enumeration literals, but that
6055 -- does not matter since these two types do not have non-standard
6056 -- representations anyway.
6058 if Is_Enumeration_Type (P_Type)
6059 and then Has_Non_Standard_Rep (P_Type)
6061 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
6063 -- For enumeration types with standard representations and all
6064 -- other cases (i.e. all integer and modular types), Enum_Rep
6065 -- is equivalent to Pos.
6068 Fold_Uint (N, Expr_Value (E1), Static);
6075 when Attribute_Enum_Val => Enum_Val : declare
6079 -- We have something like Enum_Type'Enum_Val (23), so search for a
6080 -- corresponding value in the list of Enum_Rep values for the type.
6082 Lit := First_Literal (P_Base_Type);
6084 if Enumeration_Rep (Lit) = Expr_Value (E1) then
6085 Fold_Uint (N, Enumeration_Pos (Lit), Static);
6092 Apply_Compile_Time_Constraint_Error
6093 (N, "no representation value matches",
6094 CE_Range_Check_Failed,
6095 Warn => not Static);
6105 when Attribute_Epsilon =>
6107 -- Ada 83 attribute is defined as (RM83 3.5.8)
6109 -- T'Epsilon = 2.0**(1 - T'Mantissa)
6111 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
6117 when Attribute_Exponent =>
6119 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
6125 when Attribute_First => First_Attr :
6129 if Compile_Time_Known_Value (Lo_Bound) then
6130 if Is_Real_Type (P_Type) then
6131 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
6133 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
6137 Check_Concurrent_Discriminant (Lo_Bound);
6145 when Attribute_Fixed_Value =>
6152 when Attribute_Floor =>
6154 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
6160 when Attribute_Fore =>
6161 if Compile_Time_Known_Bounds (P_Type) then
6162 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
6169 when Attribute_Fraction =>
6171 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
6173 -----------------------
6174 -- Has_Access_Values --
6175 -----------------------
6177 when Attribute_Has_Access_Values =>
6178 Rewrite (N, New_Occurrence_Of
6179 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
6180 Analyze_And_Resolve (N, Standard_Boolean);
6182 -----------------------
6183 -- Has_Discriminants --
6184 -----------------------
6186 when Attribute_Has_Discriminants =>
6187 Rewrite (N, New_Occurrence_Of (
6188 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
6189 Analyze_And_Resolve (N, Standard_Boolean);
6191 -----------------------
6192 -- Has_Tagged_Values --
6193 -----------------------
6195 when Attribute_Has_Tagged_Values =>
6196 Rewrite (N, New_Occurrence_Of
6197 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
6198 Analyze_And_Resolve (N, Standard_Boolean);
6204 when Attribute_Identity =>
6211 -- Image is a scalar attribute, but is never static, because it is
6212 -- not a static function (having a non-scalar argument (RM 4.9(22))
6213 -- However, we can constant-fold the image of an enumeration literal
6214 -- if names are available.
6216 when Attribute_Image =>
6217 if Is_Entity_Name (E1)
6218 and then Ekind (Entity (E1)) = E_Enumeration_Literal
6219 and then not Discard_Names (First_Subtype (Etype (E1)))
6220 and then not Global_Discard_Names
6223 Lit : constant Entity_Id := Entity (E1);
6227 Get_Unqualified_Decoded_Name_String (Chars (Lit));
6228 Set_Casing (All_Upper_Case);
6229 Store_String_Chars (Name_Buffer (1 .. Name_Len));
6231 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
6232 Analyze_And_Resolve (N, Standard_String);
6233 Set_Is_Static_Expression (N, False);
6241 -- Img is a scalar attribute, but is never static, because it is
6242 -- not a static function (having a non-scalar argument (RM 4.9(22))
6244 when Attribute_Img =>
6251 -- We never try to fold Integer_Value (though perhaps we could???)
6253 when Attribute_Integer_Value =>
6260 -- Invalid_Value is a scalar attribute that is never static, because
6261 -- the value is by design out of range.
6263 when Attribute_Invalid_Value =>
6270 when Attribute_Large =>
6272 -- For fixed-point, we use the identity:
6274 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6276 if Is_Fixed_Point_Type (P_Type) then
6278 Make_Op_Multiply (Loc,
6280 Make_Op_Subtract (Loc,
6284 Make_Real_Literal (Loc, Ureal_2),
6286 Make_Attribute_Reference (Loc,
6288 Attribute_Name => Name_Mantissa)),
6289 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6292 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6294 Analyze_And_Resolve (N, C_Type);
6296 -- Floating-point (Ada 83 compatibility)
6299 -- Ada 83 attribute is defined as (RM83 3.5.8)
6301 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6305 -- T'Emax = 4 * T'Mantissa
6308 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6316 when Attribute_Last => Last :
6320 if Compile_Time_Known_Value (Hi_Bound) then
6321 if Is_Real_Type (P_Type) then
6322 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6324 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6328 Check_Concurrent_Discriminant (Hi_Bound);
6336 when Attribute_Leading_Part =>
6338 Eval_Fat.Leading_Part
6339 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6345 when Attribute_Length => Length : declare
6349 -- If any index type is a formal type, or derived from one, the
6350 -- bounds are not static. Treating them as static can produce
6351 -- spurious warnings or improper constant folding.
6353 Ind := First_Index (P_Type);
6354 while Present (Ind) loop
6355 if Is_Generic_Type (Root_Type (Etype (Ind))) then
6364 -- For two compile time values, we can compute length
6366 if Compile_Time_Known_Value (Lo_Bound)
6367 and then Compile_Time_Known_Value (Hi_Bound)
6370 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6374 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6375 -- comparable, and we can figure out the difference between them.
6378 Diff : aliased Uint;
6382 Compile_Time_Compare
6383 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6386 Fold_Uint (N, Uint_1, False);
6389 Fold_Uint (N, Uint_0, False);
6392 if Diff /= No_Uint then
6393 Fold_Uint (N, Diff + 1, False);
6406 when Attribute_Machine =>
6409 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6416 when Attribute_Machine_Emax =>
6417 Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
6423 when Attribute_Machine_Emin =>
6424 Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
6426 ----------------------
6427 -- Machine_Mantissa --
6428 ----------------------
6430 when Attribute_Machine_Mantissa =>
6431 Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
6433 -----------------------
6434 -- Machine_Overflows --
6435 -----------------------
6437 when Attribute_Machine_Overflows =>
6439 -- Always true for fixed-point
6441 if Is_Fixed_Point_Type (P_Type) then
6442 Fold_Uint (N, True_Value, True);
6444 -- Floating point case
6448 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6456 when Attribute_Machine_Radix =>
6457 if Is_Fixed_Point_Type (P_Type) then
6458 if Is_Decimal_Fixed_Point_Type (P_Type)
6459 and then Machine_Radix_10 (P_Type)
6461 Fold_Uint (N, Uint_10, True);
6463 Fold_Uint (N, Uint_2, True);
6466 -- All floating-point type always have radix 2
6469 Fold_Uint (N, Uint_2, True);
6472 ----------------------
6473 -- Machine_Rounding --
6474 ----------------------
6476 -- Note: for the folding case, it is fine to treat Machine_Rounding
6477 -- exactly the same way as Rounding, since this is one of the allowed
6478 -- behaviors, and performance is not an issue here. It might be a bit
6479 -- better to give the same result as it would give at run time, even
6480 -- though the non-determinism is certainly permitted.
6482 when Attribute_Machine_Rounding =>
6484 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6486 --------------------
6487 -- Machine_Rounds --
6488 --------------------
6490 when Attribute_Machine_Rounds =>
6492 -- Always False for fixed-point
6494 if Is_Fixed_Point_Type (P_Type) then
6495 Fold_Uint (N, False_Value, True);
6497 -- Else yield proper floating-point result
6501 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6508 -- Note: Machine_Size is identical to Object_Size
6510 when Attribute_Machine_Size => Machine_Size : declare
6511 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6514 if Known_Esize (P_TypeA) then
6515 Fold_Uint (N, Esize (P_TypeA), True);
6523 when Attribute_Mantissa =>
6525 -- Fixed-point mantissa
6527 if Is_Fixed_Point_Type (P_Type) then
6529 -- Compile time foldable case
6531 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6533 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6535 -- The calculation of the obsolete Ada 83 attribute Mantissa
6536 -- is annoying, because of AI00143, quoted here:
6538 -- !question 84-01-10
6540 -- Consider the model numbers for F:
6542 -- type F is delta 1.0 range -7.0 .. 8.0;
6544 -- The wording requires that F'MANTISSA be the SMALLEST
6545 -- integer number for which each bound of the specified
6546 -- range is either a model number or lies at most small
6547 -- distant from a model number. This means F'MANTISSA
6548 -- is required to be 3 since the range -7.0 .. 7.0 fits
6549 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6550 -- number, namely, 7. Is this analysis correct? Note that
6551 -- this implies the upper bound of the range is not
6552 -- represented as a model number.
6554 -- !response 84-03-17
6556 -- The analysis is correct. The upper and lower bounds for
6557 -- a fixed point type can lie outside the range of model
6568 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6569 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6570 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6571 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6573 -- If the Bound is exactly a model number, i.e. a multiple
6574 -- of Small, then we back it off by one to get the integer
6575 -- value that must be representable.
6577 if Small_Value (P_Type) * Max_Man = Bound then
6578 Max_Man := Max_Man - 1;
6581 -- Now find corresponding size = Mantissa value
6584 while 2 ** Siz < Max_Man loop
6588 Fold_Uint (N, Siz, True);
6592 -- The case of dynamic bounds cannot be evaluated at compile
6593 -- time. Instead we use a runtime routine (see Exp_Attr).
6598 -- Floating-point Mantissa
6601 Fold_Uint (N, Mantissa, True);
6608 when Attribute_Max => Max :
6610 if Is_Real_Type (P_Type) then
6612 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6614 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6618 ----------------------------------
6619 -- Max_Alignment_For_Allocation --
6620 ----------------------------------
6622 -- Max_Alignment_For_Allocation is usually the Alignment. However,
6623 -- arrays are allocated with dope, so we need to take into account both
6624 -- the alignment of the array, which comes from the component alignment,
6625 -- and the alignment of the dope. Also, if the alignment is unknown, we
6626 -- use the max (it's OK to be pessimistic).
6628 when Attribute_Max_Alignment_For_Allocation =>
6630 A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
6632 if Known_Alignment (P_Type) and then
6633 (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
6635 A := Alignment (P_Type);
6638 Fold_Uint (N, A, Static);
6641 ----------------------------------
6642 -- Max_Size_In_Storage_Elements --
6643 ----------------------------------
6645 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6646 -- Storage_Unit boundary. We can fold any cases for which the size
6647 -- is known by the front end.
6649 when Attribute_Max_Size_In_Storage_Elements =>
6650 if Known_Esize (P_Type) then
6652 (Esize (P_Type) + System_Storage_Unit - 1) /
6653 System_Storage_Unit,
6657 --------------------
6658 -- Mechanism_Code --
6659 --------------------
6661 when Attribute_Mechanism_Code =>
6665 Mech : Mechanism_Type;
6669 Mech := Mechanism (P_Entity);
6672 Val := UI_To_Int (Expr_Value (E1));
6674 Formal := First_Formal (P_Entity);
6675 for J in 1 .. Val - 1 loop
6676 Next_Formal (Formal);
6678 Mech := Mechanism (Formal);
6682 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6690 when Attribute_Min => Min :
6692 if Is_Real_Type (P_Type) then
6694 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6697 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6705 when Attribute_Mod =>
6707 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6713 when Attribute_Model =>
6715 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
6721 when Attribute_Model_Emin =>
6722 Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
6728 when Attribute_Model_Epsilon =>
6729 Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
6731 --------------------
6732 -- Model_Mantissa --
6733 --------------------
6735 when Attribute_Model_Mantissa =>
6736 Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
6742 when Attribute_Model_Small =>
6743 Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
6749 when Attribute_Modulus =>
6750 Fold_Uint (N, Modulus (P_Type), True);
6752 --------------------
6753 -- Null_Parameter --
6754 --------------------
6756 -- Cannot fold, we know the value sort of, but the whole point is
6757 -- that there is no way to talk about this imaginary value except
6758 -- by using the attribute, so we leave it the way it is.
6760 when Attribute_Null_Parameter =>
6767 -- The Object_Size attribute for a type returns the Esize of the
6768 -- type and can be folded if this value is known.
6770 when Attribute_Object_Size => Object_Size : declare
6771 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6774 if Known_Esize (P_TypeA) then
6775 Fold_Uint (N, Esize (P_TypeA), True);
6779 -------------------------
6780 -- Passed_By_Reference --
6781 -------------------------
6783 -- Scalar types are never passed by reference
6785 when Attribute_Passed_By_Reference =>
6786 Fold_Uint (N, False_Value, True);
6792 when Attribute_Pos =>
6793 Fold_Uint (N, Expr_Value (E1), True);
6799 when Attribute_Pred => Pred :
6801 -- Floating-point case
6803 if Is_Floating_Point_Type (P_Type) then
6805 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
6809 elsif Is_Fixed_Point_Type (P_Type) then
6811 Expr_Value_R (E1) - Small_Value (P_Type), True);
6813 -- Modular integer case (wraps)
6815 elsif Is_Modular_Integer_Type (P_Type) then
6816 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
6818 -- Other scalar cases
6821 pragma Assert (Is_Scalar_Type (P_Type));
6823 if Is_Enumeration_Type (P_Type)
6824 and then Expr_Value (E1) =
6825 Expr_Value (Type_Low_Bound (P_Base_Type))
6827 Apply_Compile_Time_Constraint_Error
6828 (N, "Pred of `&''First`",
6829 CE_Overflow_Check_Failed,
6831 Warn => not Static);
6837 Fold_Uint (N, Expr_Value (E1) - 1, Static);
6845 -- No processing required, because by this stage, Range has been
6846 -- replaced by First .. Last, so this branch can never be taken.
6848 when Attribute_Range =>
6849 raise Program_Error;
6855 when Attribute_Range_Length =>
6858 -- Can fold if both bounds are compile time known
6860 if Compile_Time_Known_Value (Hi_Bound)
6861 and then Compile_Time_Known_Value (Lo_Bound)
6865 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
6869 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6870 -- comparable, and we can figure out the difference between them.
6873 Diff : aliased Uint;
6877 Compile_Time_Compare
6878 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6881 Fold_Uint (N, Uint_1, False);
6884 Fold_Uint (N, Uint_0, False);
6887 if Diff /= No_Uint then
6888 Fold_Uint (N, Diff + 1, False);
6900 when Attribute_Ref =>
6901 Fold_Uint (N, Expr_Value (E1), True);
6907 when Attribute_Remainder => Remainder : declare
6908 X : constant Ureal := Expr_Value_R (E1);
6909 Y : constant Ureal := Expr_Value_R (E2);
6912 if UR_Is_Zero (Y) then
6913 Apply_Compile_Time_Constraint_Error
6914 (N, "division by zero in Remainder",
6915 CE_Overflow_Check_Failed,
6916 Warn => not Static);
6922 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
6929 when Attribute_Round => Round :
6935 -- First we get the (exact result) in units of small
6937 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
6939 -- Now round that exactly to an integer
6941 Si := UR_To_Uint (Sr);
6943 -- Finally the result is obtained by converting back to real
6945 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
6952 when Attribute_Rounding =>
6954 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6960 when Attribute_Safe_Emax =>
6961 Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
6967 when Attribute_Safe_First =>
6968 Fold_Ureal (N, Safe_First_Value (P_Type), Static);
6974 when Attribute_Safe_Large =>
6975 if Is_Fixed_Point_Type (P_Type) then
6977 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
6979 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
6986 when Attribute_Safe_Last =>
6987 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
6993 when Attribute_Safe_Small =>
6995 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
6996 -- for fixed-point, since is the same as Small, but we implement
6997 -- it for backwards compatibility.
6999 if Is_Fixed_Point_Type (P_Type) then
7000 Fold_Ureal (N, Small_Value (P_Type), Static);
7002 -- Ada 83 Safe_Small for floating-point cases
7005 Fold_Ureal (N, Model_Small_Value (P_Type), Static);
7012 when Attribute_Scale =>
7013 Fold_Uint (N, Scale_Value (P_Type), True);
7019 when Attribute_Scaling =>
7022 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
7028 when Attribute_Signed_Zeros =>
7030 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
7036 -- Size attribute returns the RM size. All scalar types can be folded,
7037 -- as well as any types for which the size is known by the front end,
7038 -- including any type for which a size attribute is specified.
7040 when Attribute_Size | Attribute_VADS_Size => Size : declare
7041 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7044 if RM_Size (P_TypeA) /= Uint_0 then
7048 if Id = Attribute_VADS_Size or else Use_VADS_Size then
7050 S : constant Node_Id := Size_Clause (P_TypeA);
7053 -- If a size clause applies, then use the size from it.
7054 -- This is one of the rare cases where we can use the
7055 -- Size_Clause field for a subtype when Has_Size_Clause
7056 -- is False. Consider:
7058 -- type x is range 1 .. 64;
7059 -- for x'size use 12;
7060 -- subtype y is x range 0 .. 3;
7062 -- Here y has a size clause inherited from x, but normally
7063 -- it does not apply, and y'size is 2. However, y'VADS_Size
7064 -- is indeed 12 and not 2.
7067 and then Is_OK_Static_Expression (Expression (S))
7069 Fold_Uint (N, Expr_Value (Expression (S)), True);
7071 -- If no size is specified, then we simply use the object
7072 -- size in the VADS_Size case (e.g. Natural'Size is equal
7073 -- to Integer'Size, not one less).
7076 Fold_Uint (N, Esize (P_TypeA), True);
7080 -- Normal case (Size) in which case we want the RM_Size
7085 Static and then Is_Discrete_Type (P_TypeA));
7094 when Attribute_Small =>
7096 -- The floating-point case is present only for Ada 83 compatibility.
7097 -- Note that strictly this is an illegal addition, since we are
7098 -- extending an Ada 95 defined attribute, but we anticipate an
7099 -- ARG ruling that will permit this.
7101 if Is_Floating_Point_Type (P_Type) then
7103 -- Ada 83 attribute is defined as (RM83 3.5.8)
7105 -- T'Small = 2.0**(-T'Emax - 1)
7109 -- T'Emax = 4 * T'Mantissa
7111 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
7113 -- Normal Ada 95 fixed-point case
7116 Fold_Ureal (N, Small_Value (P_Type), True);
7123 when Attribute_Stream_Size =>
7130 when Attribute_Succ => Succ :
7132 -- Floating-point case
7134 if Is_Floating_Point_Type (P_Type) then
7136 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
7140 elsif Is_Fixed_Point_Type (P_Type) then
7142 Expr_Value_R (E1) + Small_Value (P_Type), Static);
7144 -- Modular integer case (wraps)
7146 elsif Is_Modular_Integer_Type (P_Type) then
7147 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
7149 -- Other scalar cases
7152 pragma Assert (Is_Scalar_Type (P_Type));
7154 if Is_Enumeration_Type (P_Type)
7155 and then Expr_Value (E1) =
7156 Expr_Value (Type_High_Bound (P_Base_Type))
7158 Apply_Compile_Time_Constraint_Error
7159 (N, "Succ of `&''Last`",
7160 CE_Overflow_Check_Failed,
7162 Warn => not Static);
7167 Fold_Uint (N, Expr_Value (E1) + 1, Static);
7176 when Attribute_Truncation =>
7178 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
7184 when Attribute_Type_Class => Type_Class : declare
7185 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
7189 if Is_Descendent_Of_Address (Typ) then
7190 Id := RE_Type_Class_Address;
7192 elsif Is_Enumeration_Type (Typ) then
7193 Id := RE_Type_Class_Enumeration;
7195 elsif Is_Integer_Type (Typ) then
7196 Id := RE_Type_Class_Integer;
7198 elsif Is_Fixed_Point_Type (Typ) then
7199 Id := RE_Type_Class_Fixed_Point;
7201 elsif Is_Floating_Point_Type (Typ) then
7202 Id := RE_Type_Class_Floating_Point;
7204 elsif Is_Array_Type (Typ) then
7205 Id := RE_Type_Class_Array;
7207 elsif Is_Record_Type (Typ) then
7208 Id := RE_Type_Class_Record;
7210 elsif Is_Access_Type (Typ) then
7211 Id := RE_Type_Class_Access;
7213 elsif Is_Enumeration_Type (Typ) then
7214 Id := RE_Type_Class_Enumeration;
7216 elsif Is_Task_Type (Typ) then
7217 Id := RE_Type_Class_Task;
7219 -- We treat protected types like task types. It would make more
7220 -- sense to have another enumeration value, but after all the
7221 -- whole point of this feature is to be exactly DEC compatible,
7222 -- and changing the type Type_Class would not meet this requirement.
7224 elsif Is_Protected_Type (Typ) then
7225 Id := RE_Type_Class_Task;
7227 -- Not clear if there are any other possibilities, but if there
7228 -- are, then we will treat them as the address case.
7231 Id := RE_Type_Class_Address;
7234 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
7237 -----------------------
7238 -- Unbiased_Rounding --
7239 -----------------------
7241 when Attribute_Unbiased_Rounding =>
7243 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7246 -------------------------
7247 -- Unconstrained_Array --
7248 -------------------------
7250 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7251 Typ : constant Entity_Id := Underlying_Type (P_Type);
7254 Rewrite (N, New_Occurrence_Of (
7256 Is_Array_Type (P_Type)
7257 and then not Is_Constrained (Typ)), Loc));
7259 -- Analyze and resolve as boolean, note that this attribute is
7260 -- a static attribute in GNAT.
7262 Analyze_And_Resolve (N, Standard_Boolean);
7264 end Unconstrained_Array;
7270 -- Processing is shared with Size
7276 when Attribute_Val => Val :
7278 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7280 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7282 Apply_Compile_Time_Constraint_Error
7283 (N, "Val expression out of range",
7284 CE_Range_Check_Failed,
7285 Warn => not Static);
7291 Fold_Uint (N, Expr_Value (E1), Static);
7299 -- The Value_Size attribute for a type returns the RM size of the
7300 -- type. This an always be folded for scalar types, and can also
7301 -- be folded for non-scalar types if the size is set.
7303 when Attribute_Value_Size => Value_Size : declare
7304 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7306 if RM_Size (P_TypeA) /= Uint_0 then
7307 Fold_Uint (N, RM_Size (P_TypeA), True);
7315 -- Version can never be static
7317 when Attribute_Version =>
7324 -- Wide_Image is a scalar attribute, but is never static, because it
7325 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7327 when Attribute_Wide_Image =>
7330 ---------------------
7331 -- Wide_Wide_Image --
7332 ---------------------
7334 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7335 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7337 when Attribute_Wide_Wide_Image =>
7340 ---------------------
7341 -- Wide_Wide_Width --
7342 ---------------------
7344 -- Processing for Wide_Wide_Width is combined with Width
7350 -- Processing for Wide_Width is combined with Width
7356 -- This processing also handles the case of Wide_[Wide_]Width
7358 when Attribute_Width |
7359 Attribute_Wide_Width |
7360 Attribute_Wide_Wide_Width => Width :
7362 if Compile_Time_Known_Bounds (P_Type) then
7364 -- Floating-point types
7366 if Is_Floating_Point_Type (P_Type) then
7368 -- Width is zero for a null range (RM 3.5 (38))
7370 if Expr_Value_R (Type_High_Bound (P_Type)) <
7371 Expr_Value_R (Type_Low_Bound (P_Type))
7373 Fold_Uint (N, Uint_0, True);
7376 -- For floating-point, we have +N.dddE+nnn where length
7377 -- of ddd is determined by type'Digits - 1, but is one
7378 -- if Digits is one (RM 3.5 (33)).
7380 -- nnn is set to 2 for Short_Float and Float (32 bit
7381 -- floats), and 3 for Long_Float and Long_Long_Float.
7382 -- For machines where Long_Long_Float is the IEEE
7383 -- extended precision type, the exponent takes 4 digits.
7387 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7390 if Esize (P_Type) <= 32 then
7392 elsif Esize (P_Type) = 64 then
7398 Fold_Uint (N, UI_From_Int (Len), True);
7402 -- Fixed-point types
7404 elsif Is_Fixed_Point_Type (P_Type) then
7406 -- Width is zero for a null range (RM 3.5 (38))
7408 if Expr_Value (Type_High_Bound (P_Type)) <
7409 Expr_Value (Type_Low_Bound (P_Type))
7411 Fold_Uint (N, Uint_0, True);
7413 -- The non-null case depends on the specific real type
7416 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7419 (N, UI_From_Int (Fore_Value + 1) + Aft_Value (P_Type),
7427 R : constant Entity_Id := Root_Type (P_Type);
7428 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7429 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7442 -- Width for types derived from Standard.Character
7443 -- and Standard.Wide_[Wide_]Character.
7445 elsif Is_Standard_Character_Type (P_Type) then
7448 -- Set W larger if needed
7450 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7452 -- All wide characters look like Hex_hhhhhhhh
7456 -- No need to compute this more than once!
7461 C := Character'Val (J);
7463 -- Test for all cases where Character'Image
7464 -- yields an image that is longer than three
7465 -- characters. First the cases of Reserved_xxx
7466 -- names (length = 12).
7469 when Reserved_128 | Reserved_129 |
7470 Reserved_132 | Reserved_153
7473 when BS | HT | LF | VT | FF | CR |
7474 SO | SI | EM | FS | GS | RS |
7475 US | RI | MW | ST | PM
7478 when NUL | SOH | STX | ETX | EOT |
7479 ENQ | ACK | BEL | DLE | DC1 |
7480 DC2 | DC3 | DC4 | NAK | SYN |
7481 ETB | CAN | SUB | ESC | DEL |
7482 BPH | NBH | NEL | SSA | ESA |
7483 HTS | HTJ | VTS | PLD | PLU |
7484 SS2 | SS3 | DCS | PU1 | PU2 |
7485 STS | CCH | SPA | EPA | SOS |
7486 SCI | CSI | OSC | APC
7489 when Space .. Tilde |
7490 No_Break_Space .. LC_Y_Diaeresis
7492 -- Special case of soft hyphen in Ada 2005
7494 if C = Character'Val (16#AD#)
7495 and then Ada_Version >= Ada_2005
7503 W := Int'Max (W, Wt);
7507 -- Width for types derived from Standard.Boolean
7509 elsif R = Standard_Boolean then
7516 -- Width for integer types
7518 elsif Is_Integer_Type (P_Type) then
7519 T := UI_Max (abs Lo, abs Hi);
7527 -- Only remaining possibility is user declared enum type
7530 pragma Assert (Is_Enumeration_Type (P_Type));
7533 L := First_Literal (P_Type);
7535 while Present (L) loop
7537 -- Only pay attention to in range characters
7539 if Lo <= Enumeration_Pos (L)
7540 and then Enumeration_Pos (L) <= Hi
7542 -- For Width case, use decoded name
7544 if Id = Attribute_Width then
7545 Get_Decoded_Name_String (Chars (L));
7546 Wt := Nat (Name_Len);
7548 -- For Wide_[Wide_]Width, use encoded name, and
7549 -- then adjust for the encoding.
7552 Get_Name_String (Chars (L));
7554 -- Character literals are always of length 3
7556 if Name_Buffer (1) = 'Q' then
7559 -- Otherwise loop to adjust for upper/wide chars
7562 Wt := Nat (Name_Len);
7564 for J in 1 .. Name_Len loop
7565 if Name_Buffer (J) = 'U' then
7567 elsif Name_Buffer (J) = 'W' then
7574 W := Int'Max (W, Wt);
7581 Fold_Uint (N, UI_From_Int (W), True);
7587 -- The following attributes denote functions that cannot be folded
7589 when Attribute_From_Any |
7591 Attribute_TypeCode =>
7594 -- The following attributes can never be folded, and furthermore we
7595 -- should not even have entered the case statement for any of these.
7596 -- Note that in some cases, the values have already been folded as
7597 -- a result of the processing in Analyze_Attribute.
7599 when Attribute_Abort_Signal |
7602 Attribute_Address_Size |
7603 Attribute_Asm_Input |
7604 Attribute_Asm_Output |
7606 Attribute_Bit_Order |
7607 Attribute_Bit_Position |
7608 Attribute_Callable |
7611 Attribute_Code_Address |
7612 Attribute_Compiler_Version |
7614 Attribute_Default_Bit_Order |
7615 Attribute_Elaborated |
7616 Attribute_Elab_Body |
7617 Attribute_Elab_Spec |
7619 Attribute_External_Tag |
7620 Attribute_Fast_Math |
7621 Attribute_First_Bit |
7623 Attribute_Last_Bit |
7624 Attribute_Maximum_Alignment |
7627 Attribute_Partition_ID |
7628 Attribute_Pool_Address |
7629 Attribute_Position |
7630 Attribute_Priority |
7633 Attribute_Storage_Pool |
7634 Attribute_Storage_Size |
7635 Attribute_Storage_Unit |
7636 Attribute_Stub_Type |
7638 Attribute_Target_Name |
7639 Attribute_Terminated |
7640 Attribute_To_Address |
7641 Attribute_Type_Key |
7642 Attribute_UET_Address |
7643 Attribute_Unchecked_Access |
7644 Attribute_Universal_Literal_String |
7645 Attribute_Unrestricted_Access |
7648 Attribute_Wchar_T_Size |
7649 Attribute_Wide_Value |
7650 Attribute_Wide_Wide_Value |
7651 Attribute_Word_Size |
7654 raise Program_Error;
7657 -- At the end of the case, one more check. If we did a static evaluation
7658 -- so that the result is now a literal, then set Is_Static_Expression
7659 -- in the constant only if the prefix type is a static subtype. For
7660 -- non-static subtypes, the folding is still OK, but not static.
7662 -- An exception is the GNAT attribute Constrained_Array which is
7663 -- defined to be a static attribute in all cases.
7665 if Nkind_In (N, N_Integer_Literal,
7667 N_Character_Literal,
7669 or else (Is_Entity_Name (N)
7670 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7672 Set_Is_Static_Expression (N, Static);
7674 -- If this is still an attribute reference, then it has not been folded
7675 -- and that means that its expressions are in a non-static context.
7677 elsif Nkind (N) = N_Attribute_Reference then
7680 -- Note: the else case not covered here are odd cases where the
7681 -- processing has transformed the attribute into something other
7682 -- than a constant. Nothing more to do in such cases.
7689 ------------------------------
7690 -- Is_Anonymous_Tagged_Base --
7691 ------------------------------
7693 function Is_Anonymous_Tagged_Base
7700 Anon = Current_Scope
7701 and then Is_Itype (Anon)
7702 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
7703 end Is_Anonymous_Tagged_Base;
7705 --------------------------------
7706 -- Name_Implies_Lvalue_Prefix --
7707 --------------------------------
7709 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
7710 pragma Assert (Is_Attribute_Name (Nam));
7712 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
7713 end Name_Implies_Lvalue_Prefix;
7715 -----------------------
7716 -- Resolve_Attribute --
7717 -----------------------
7719 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
7720 Loc : constant Source_Ptr := Sloc (N);
7721 P : constant Node_Id := Prefix (N);
7722 Aname : constant Name_Id := Attribute_Name (N);
7723 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7724 Btyp : constant Entity_Id := Base_Type (Typ);
7725 Des_Btyp : Entity_Id;
7726 Index : Interp_Index;
7728 Nom_Subt : Entity_Id;
7730 procedure Accessibility_Message;
7731 -- Error, or warning within an instance, if the static accessibility
7732 -- rules of 3.10.2 are violated.
7734 ---------------------------
7735 -- Accessibility_Message --
7736 ---------------------------
7738 procedure Accessibility_Message is
7739 Indic : Node_Id := Parent (Parent (N));
7742 -- In an instance, this is a runtime check, but one we
7743 -- know will fail, so generate an appropriate warning.
7745 if In_Instance_Body then
7746 Error_Msg_F ("?non-local pointer cannot point to local object", P);
7748 ("\?Program_Error will be raised at run time", P);
7750 Make_Raise_Program_Error (Loc,
7751 Reason => PE_Accessibility_Check_Failed));
7756 Error_Msg_F ("non-local pointer cannot point to local object", P);
7758 -- Check for case where we have a missing access definition
7760 if Is_Record_Type (Current_Scope)
7762 Nkind_In (Parent (N), N_Discriminant_Association,
7763 N_Index_Or_Discriminant_Constraint)
7765 Indic := Parent (Parent (N));
7766 while Present (Indic)
7767 and then Nkind (Indic) /= N_Subtype_Indication
7769 Indic := Parent (Indic);
7772 if Present (Indic) then
7774 ("\use an access definition for" &
7775 " the access discriminant of&",
7776 N, Entity (Subtype_Mark (Indic)));
7780 end Accessibility_Message;
7782 -- Start of processing for Resolve_Attribute
7785 -- If error during analysis, no point in continuing, except for array
7786 -- types, where we get better recovery by using unconstrained indexes
7787 -- than nothing at all (see Check_Array_Type).
7790 and then Attr_Id /= Attribute_First
7791 and then Attr_Id /= Attribute_Last
7792 and then Attr_Id /= Attribute_Length
7793 and then Attr_Id /= Attribute_Range
7798 -- If attribute was universal type, reset to actual type
7800 if Etype (N) = Universal_Integer
7801 or else Etype (N) = Universal_Real
7806 -- Remaining processing depends on attribute
7814 -- For access attributes, if the prefix denotes an entity, it is
7815 -- interpreted as a name, never as a call. It may be overloaded,
7816 -- in which case resolution uses the profile of the context type.
7817 -- Otherwise prefix must be resolved.
7819 when Attribute_Access
7820 | Attribute_Unchecked_Access
7821 | Attribute_Unrestricted_Access =>
7825 if Is_Variable (P) then
7826 Note_Possible_Modification (P, Sure => False);
7829 -- The following comes from a query by Adam Beneschan, concerning
7830 -- improper use of universal_access in equality tests involving
7831 -- anonymous access types. Another good reason for 'Ref, but
7832 -- for now disable the test, which breaks several filed tests.
7834 if Ekind (Typ) = E_Anonymous_Access_Type
7835 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
7838 Error_Msg_N ("need unique type to resolve 'Access", N);
7839 Error_Msg_N ("\qualify attribute with some access type", N);
7842 if Is_Entity_Name (P) then
7843 if Is_Overloaded (P) then
7844 Get_First_Interp (P, Index, It);
7845 while Present (It.Nam) loop
7846 if Type_Conformant (Designated_Type (Typ), It.Nam) then
7847 Set_Entity (P, It.Nam);
7849 -- The prefix is definitely NOT overloaded anymore at
7850 -- this point, so we reset the Is_Overloaded flag to
7851 -- avoid any confusion when reanalyzing the node.
7853 Set_Is_Overloaded (P, False);
7854 Set_Is_Overloaded (N, False);
7855 Generate_Reference (Entity (P), P);
7859 Get_Next_Interp (Index, It);
7862 -- If Prefix is a subprogram name, it is frozen by this
7865 -- If it is a type, there is nothing to resolve.
7866 -- If it is an object, complete its resolution.
7868 elsif Is_Overloadable (Entity (P)) then
7870 -- Avoid insertion of freeze actions in spec expression mode
7872 if not In_Spec_Expression then
7873 Freeze_Before (N, Entity (P));
7876 elsif Is_Type (Entity (P)) then
7882 Error_Msg_Name_1 := Aname;
7884 if not Is_Entity_Name (P) then
7887 elsif Is_Overloadable (Entity (P))
7888 and then Is_Abstract_Subprogram (Entity (P))
7890 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
7891 Set_Etype (N, Any_Type);
7893 elsif Convention (Entity (P)) = Convention_Intrinsic then
7894 if Ekind (Entity (P)) = E_Enumeration_Literal then
7896 ("prefix of % attribute cannot be enumeration literal",
7900 ("prefix of % attribute cannot be intrinsic", P);
7903 Set_Etype (N, Any_Type);
7906 -- Assignments, return statements, components of aggregates,
7907 -- generic instantiations will require convention checks if
7908 -- the type is an access to subprogram. Given that there will
7909 -- also be accessibility checks on those, this is where the
7910 -- checks can eventually be centralized ???
7912 if Ekind_In (Btyp, E_Access_Subprogram_Type,
7913 E_Anonymous_Access_Subprogram_Type,
7914 E_Access_Protected_Subprogram_Type,
7915 E_Anonymous_Access_Protected_Subprogram_Type)
7917 -- Deal with convention mismatch
7919 if Convention (Designated_Type (Btyp)) /=
7920 Convention (Entity (P))
7923 ("subprogram & has wrong convention", P, Entity (P));
7925 ("\does not match convention of access type &",
7928 if not Has_Convention_Pragma (Btyp) then
7930 ("\probable missing pragma Convention for &",
7935 Check_Subtype_Conformant
7936 (New_Id => Entity (P),
7937 Old_Id => Designated_Type (Btyp),
7941 if Attr_Id = Attribute_Unchecked_Access then
7942 Error_Msg_Name_1 := Aname;
7944 ("attribute% cannot be applied to a subprogram", P);
7946 elsif Aname = Name_Unrestricted_Access then
7947 null; -- Nothing to check
7949 -- Check the static accessibility rule of 3.10.2(32).
7950 -- This rule also applies within the private part of an
7951 -- instantiation. This rule does not apply to anonymous
7952 -- access-to-subprogram types in access parameters.
7954 elsif Attr_Id = Attribute_Access
7955 and then not In_Instance_Body
7957 (Ekind (Btyp) = E_Access_Subprogram_Type
7958 or else Is_Local_Anonymous_Access (Btyp))
7960 and then Subprogram_Access_Level (Entity (P)) >
7961 Type_Access_Level (Btyp)
7964 ("subprogram must not be deeper than access type", P);
7966 -- Check the restriction of 3.10.2(32) that disallows the
7967 -- access attribute within a generic body when the ultimate
7968 -- ancestor of the type of the attribute is declared outside
7969 -- of the generic unit and the subprogram is declared within
7970 -- that generic unit. This includes any such attribute that
7971 -- occurs within the body of a generic unit that is a child
7972 -- of the generic unit where the subprogram is declared.
7974 -- The rule also prohibits applying the attribute when the
7975 -- access type is a generic formal access type (since the
7976 -- level of the actual type is not known). This restriction
7977 -- does not apply when the attribute type is an anonymous
7978 -- access-to-subprogram type. Note that this check was
7979 -- revised by AI-229, because the originally Ada 95 rule
7980 -- was too lax. The original rule only applied when the
7981 -- subprogram was declared within the body of the generic,
7982 -- which allowed the possibility of dangling references).
7983 -- The rule was also too strict in some case, in that it
7984 -- didn't permit the access to be declared in the generic
7985 -- spec, whereas the revised rule does (as long as it's not
7988 -- There are a couple of subtleties of the test for applying
7989 -- the check that are worth noting. First, we only apply it
7990 -- when the levels of the subprogram and access type are the
7991 -- same (the case where the subprogram is statically deeper
7992 -- was applied above, and the case where the type is deeper
7993 -- is always safe). Second, we want the check to apply
7994 -- within nested generic bodies and generic child unit
7995 -- bodies, but not to apply to an attribute that appears in
7996 -- the generic unit's specification. This is done by testing
7997 -- that the attribute's innermost enclosing generic body is
7998 -- not the same as the innermost generic body enclosing the
7999 -- generic unit where the subprogram is declared (we don't
8000 -- want the check to apply when the access attribute is in
8001 -- the spec and there's some other generic body enclosing
8002 -- generic). Finally, there's no point applying the check
8003 -- when within an instance, because any violations will have
8004 -- been caught by the compilation of the generic unit.
8006 -- Note that we relax this check in CodePeer mode for
8007 -- compatibility with legacy code, since CodePeer is an
8008 -- Ada source code analyzer, not a strict compiler.
8009 -- ??? Note that a better approach would be to have a
8010 -- separate switch to relax this rule, and enable this
8011 -- switch in CodePeer mode.
8013 elsif Attr_Id = Attribute_Access
8014 and then not CodePeer_Mode
8015 and then not In_Instance
8016 and then Present (Enclosing_Generic_Unit (Entity (P)))
8017 and then Present (Enclosing_Generic_Body (N))
8018 and then Enclosing_Generic_Body (N) /=
8019 Enclosing_Generic_Body
8020 (Enclosing_Generic_Unit (Entity (P)))
8021 and then Subprogram_Access_Level (Entity (P)) =
8022 Type_Access_Level (Btyp)
8023 and then Ekind (Btyp) /=
8024 E_Anonymous_Access_Subprogram_Type
8025 and then Ekind (Btyp) /=
8026 E_Anonymous_Access_Protected_Subprogram_Type
8028 -- The attribute type's ultimate ancestor must be
8029 -- declared within the same generic unit as the
8030 -- subprogram is declared. The error message is
8031 -- specialized to say "ancestor" for the case where the
8032 -- access type is not its own ancestor, since saying
8033 -- simply "access type" would be very confusing.
8035 if Enclosing_Generic_Unit (Entity (P)) /=
8036 Enclosing_Generic_Unit (Root_Type (Btyp))
8039 ("''Access attribute not allowed in generic body",
8042 if Root_Type (Btyp) = Btyp then
8045 "access type & is declared outside " &
8046 "generic unit (RM 3.10.2(32))", N, Btyp);
8049 ("\because ancestor of " &
8050 "access type & is declared outside " &
8051 "generic unit (RM 3.10.2(32))", N, Btyp);
8055 ("\move ''Access to private part, or " &
8056 "(Ada 2005) use anonymous access type instead of &",
8059 -- If the ultimate ancestor of the attribute's type is
8060 -- a formal type, then the attribute is illegal because
8061 -- the actual type might be declared at a higher level.
8062 -- The error message is specialized to say "ancestor"
8063 -- for the case where the access type is not its own
8064 -- ancestor, since saying simply "access type" would be
8067 elsif Is_Generic_Type (Root_Type (Btyp)) then
8068 if Root_Type (Btyp) = Btyp then
8070 ("access type must not be a generic formal type",
8074 ("ancestor access type must not be a generic " &
8081 -- If this is a renaming, an inherited operation, or a
8082 -- subprogram instance, use the original entity. This may make
8083 -- the node type-inconsistent, so this transformation can only
8084 -- be done if the node will not be reanalyzed. In particular,
8085 -- if it is within a default expression, the transformation
8086 -- must be delayed until the default subprogram is created for
8087 -- it, when the enclosing subprogram is frozen.
8089 if Is_Entity_Name (P)
8090 and then Is_Overloadable (Entity (P))
8091 and then Present (Alias (Entity (P)))
8092 and then Expander_Active
8095 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8098 elsif Nkind (P) = N_Selected_Component
8099 and then Is_Overloadable (Entity (Selector_Name (P)))
8101 -- Protected operation. If operation is overloaded, must
8102 -- disambiguate. Prefix that denotes protected object itself
8103 -- is resolved with its own type.
8105 if Attr_Id = Attribute_Unchecked_Access then
8106 Error_Msg_Name_1 := Aname;
8108 ("attribute% cannot be applied to protected operation", P);
8111 Resolve (Prefix (P));
8112 Generate_Reference (Entity (Selector_Name (P)), P);
8114 elsif Is_Overloaded (P) then
8116 -- Use the designated type of the context to disambiguate
8117 -- Note that this was not strictly conformant to Ada 95,
8118 -- but was the implementation adopted by most Ada 95 compilers.
8119 -- The use of the context type to resolve an Access attribute
8120 -- reference is now mandated in AI-235 for Ada 2005.
8123 Index : Interp_Index;
8127 Get_First_Interp (P, Index, It);
8128 while Present (It.Typ) loop
8129 if Covers (Designated_Type (Typ), It.Typ) then
8130 Resolve (P, It.Typ);
8134 Get_Next_Interp (Index, It);
8141 -- X'Access is illegal if X denotes a constant and the access type
8142 -- is access-to-variable. Same for 'Unchecked_Access. The rule
8143 -- does not apply to 'Unrestricted_Access. If the reference is a
8144 -- default-initialized aggregate component for a self-referential
8145 -- type the reference is legal.
8147 if not (Ekind (Btyp) = E_Access_Subprogram_Type
8148 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
8149 or else (Is_Record_Type (Btyp)
8151 Present (Corresponding_Remote_Type (Btyp)))
8152 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8153 or else Ekind (Btyp)
8154 = E_Anonymous_Access_Protected_Subprogram_Type
8155 or else Is_Access_Constant (Btyp)
8156 or else Is_Variable (P)
8157 or else Attr_Id = Attribute_Unrestricted_Access)
8159 if Is_Entity_Name (P)
8160 and then Is_Type (Entity (P))
8162 -- Legality of a self-reference through an access
8163 -- attribute has been verified in Analyze_Access_Attribute.
8167 elsif Comes_From_Source (N) then
8168 Error_Msg_F ("access-to-variable designates constant", P);
8172 Des_Btyp := Designated_Type (Btyp);
8174 if Ada_Version >= Ada_2005
8175 and then Is_Incomplete_Type (Des_Btyp)
8177 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
8178 -- imported entity, and the non-limited view is visible, make
8179 -- use of it. If it is an incomplete subtype, use the base type
8182 if From_With_Type (Des_Btyp)
8183 and then Present (Non_Limited_View (Des_Btyp))
8185 Des_Btyp := Non_Limited_View (Des_Btyp);
8187 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
8188 Des_Btyp := Etype (Des_Btyp);
8192 if (Attr_Id = Attribute_Access
8194 Attr_Id = Attribute_Unchecked_Access)
8195 and then (Ekind (Btyp) = E_General_Access_Type
8196 or else Ekind (Btyp) = E_Anonymous_Access_Type)
8198 -- Ada 2005 (AI-230): Check the accessibility of anonymous
8199 -- access types for stand-alone objects, record and array
8200 -- components, and return objects. For a component definition
8201 -- the level is the same of the enclosing composite type.
8203 if Ada_Version >= Ada_2005
8204 and then Is_Local_Anonymous_Access (Btyp)
8205 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8206 and then Attr_Id = Attribute_Access
8208 -- In an instance, this is a runtime check, but one we
8209 -- know will fail, so generate an appropriate warning.
8211 if In_Instance_Body then
8213 ("?non-local pointer cannot point to local object", P);
8215 ("\?Program_Error will be raised at run time", P);
8217 Make_Raise_Program_Error (Loc,
8218 Reason => PE_Accessibility_Check_Failed));
8223 ("non-local pointer cannot point to local object", P);
8227 if Is_Dependent_Component_Of_Mutable_Object (P) then
8229 ("illegal attribute for discriminant-dependent component",
8233 -- Check static matching rule of 3.10.2(27). Nominal subtype
8234 -- of the prefix must statically match the designated type.
8236 Nom_Subt := Etype (P);
8238 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
8239 Nom_Subt := Base_Type (Nom_Subt);
8242 if Is_Tagged_Type (Designated_Type (Typ)) then
8244 -- If the attribute is in the context of an access
8245 -- parameter, then the prefix is allowed to be of the
8246 -- class-wide type (by AI-127).
8248 if Ekind (Typ) = E_Anonymous_Access_Type then
8249 if not Covers (Designated_Type (Typ), Nom_Subt)
8250 and then not Covers (Nom_Subt, Designated_Type (Typ))
8256 Desig := Designated_Type (Typ);
8258 if Is_Class_Wide_Type (Desig) then
8259 Desig := Etype (Desig);
8262 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8267 ("type of prefix: & not compatible",
8270 ("\with &, the expected designated type",
8271 P, Designated_Type (Typ));
8276 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8278 (not Is_Class_Wide_Type (Designated_Type (Typ))
8279 and then Is_Class_Wide_Type (Nom_Subt))
8282 ("type of prefix: & is not covered", P, Nom_Subt);
8284 ("\by &, the expected designated type" &
8285 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8288 if Is_Class_Wide_Type (Designated_Type (Typ))
8289 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8290 and then Is_Constrained (Etype (Designated_Type (Typ)))
8291 and then Designated_Type (Typ) /= Nom_Subt
8293 Apply_Discriminant_Check
8294 (N, Etype (Designated_Type (Typ)));
8297 -- Ada 2005 (AI-363): Require static matching when designated
8298 -- type has discriminants and a constrained partial view, since
8299 -- in general objects of such types are mutable, so we can't
8300 -- allow the access value to designate a constrained object
8301 -- (because access values must be assumed to designate mutable
8302 -- objects when designated type does not impose a constraint).
8304 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8307 elsif Has_Discriminants (Designated_Type (Typ))
8308 and then not Is_Constrained (Des_Btyp)
8310 (Ada_Version < Ada_2005
8312 not Has_Constrained_Partial_View
8313 (Designated_Type (Base_Type (Typ))))
8319 ("object subtype must statically match "
8320 & "designated subtype", P);
8322 if Is_Entity_Name (P)
8323 and then Is_Array_Type (Designated_Type (Typ))
8326 D : constant Node_Id := Declaration_Node (Entity (P));
8329 Error_Msg_N ("aliased object has explicit bounds?",
8331 Error_Msg_N ("\declare without bounds"
8332 & " (and with explicit initialization)?", D);
8333 Error_Msg_N ("\for use with unconstrained access?", D);
8338 -- Check the static accessibility rule of 3.10.2(28).
8339 -- Note that this check is not performed for the
8340 -- case of an anonymous access type, since the access
8341 -- attribute is always legal in such a context.
8343 if Attr_Id /= Attribute_Unchecked_Access
8344 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8345 and then Ekind (Btyp) = E_General_Access_Type
8347 Accessibility_Message;
8352 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
8353 E_Anonymous_Access_Protected_Subprogram_Type)
8355 if Is_Entity_Name (P)
8356 and then not Is_Protected_Type (Scope (Entity (P)))
8358 Error_Msg_F ("context requires a protected subprogram", P);
8360 -- Check accessibility of protected object against that of the
8361 -- access type, but only on user code, because the expander
8362 -- creates access references for handlers. If the context is an
8363 -- anonymous_access_to_protected, there are no accessibility
8364 -- checks either. Omit check entirely for Unrestricted_Access.
8366 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8367 and then Comes_From_Source (N)
8368 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8369 and then Attr_Id /= Attribute_Unrestricted_Access
8371 Accessibility_Message;
8375 elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
8376 E_Anonymous_Access_Subprogram_Type)
8377 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8379 Error_Msg_F ("context requires a non-protected subprogram", P);
8382 -- The context cannot be a pool-specific type, but this is a
8383 -- legality rule, not a resolution rule, so it must be checked
8384 -- separately, after possibly disambiguation (see AI-245).
8386 if Ekind (Btyp) = E_Access_Type
8387 and then Attr_Id /= Attribute_Unrestricted_Access
8389 Wrong_Type (N, Typ);
8392 -- The context may be a constrained access type (however ill-
8393 -- advised such subtypes might be) so in order to generate a
8394 -- constraint check when needed set the type of the attribute
8395 -- reference to the base type of the context.
8397 Set_Etype (N, Btyp);
8399 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8401 if Attr_Id /= Attribute_Unrestricted_Access then
8402 if Is_Atomic_Object (P)
8403 and then not Is_Atomic (Designated_Type (Typ))
8406 ("access to atomic object cannot yield access-to-" &
8407 "non-atomic type", P);
8409 elsif Is_Volatile_Object (P)
8410 and then not Is_Volatile (Designated_Type (Typ))
8413 ("access to volatile object cannot yield access-to-" &
8414 "non-volatile type", P);
8418 if Is_Entity_Name (P) then
8419 Set_Address_Taken (Entity (P));
8421 end Access_Attribute;
8427 -- Deal with resolving the type for Address attribute, overloading
8428 -- is not permitted here, since there is no context to resolve it.
8430 when Attribute_Address | Attribute_Code_Address =>
8431 Address_Attribute : begin
8433 -- To be safe, assume that if the address of a variable is taken,
8434 -- it may be modified via this address, so note modification.
8436 if Is_Variable (P) then
8437 Note_Possible_Modification (P, Sure => False);
8440 if Nkind (P) in N_Subexpr
8441 and then Is_Overloaded (P)
8443 Get_First_Interp (P, Index, It);
8444 Get_Next_Interp (Index, It);
8446 if Present (It.Nam) then
8447 Error_Msg_Name_1 := Aname;
8449 ("prefix of % attribute cannot be overloaded", P);
8453 if not Is_Entity_Name (P)
8454 or else not Is_Overloadable (Entity (P))
8456 if not Is_Task_Type (Etype (P))
8457 or else Nkind (P) = N_Explicit_Dereference
8463 -- If this is the name of a derived subprogram, or that of a
8464 -- generic actual, the address is that of the original entity.
8466 if Is_Entity_Name (P)
8467 and then Is_Overloadable (Entity (P))
8468 and then Present (Alias (Entity (P)))
8471 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8474 if Is_Entity_Name (P) then
8475 Set_Address_Taken (Entity (P));
8478 if Nkind (P) = N_Slice then
8480 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8481 -- even if the array is packed and the slice itself is not
8482 -- addressable. Transform the prefix into an indexed component.
8484 -- Note that the transformation is safe only if we know that
8485 -- the slice is non-null. That is because a null slice can have
8486 -- an out of bounds index value.
8488 -- Right now, gigi blows up if given 'Address on a slice as a
8489 -- result of some incorrect freeze nodes generated by the front
8490 -- end, and this covers up that bug in one case, but the bug is
8491 -- likely still there in the cases not handled by this code ???
8493 -- It's not clear what 'Address *should* return for a null
8494 -- slice with out of bounds indexes, this might be worth an ARG
8497 -- One approach would be to do a length check unconditionally,
8498 -- and then do the transformation below unconditionally, but
8499 -- analyze with checks off, avoiding the problem of the out of
8500 -- bounds index. This approach would interpret the address of
8501 -- an out of bounds null slice as being the address where the
8502 -- array element would be if there was one, which is probably
8503 -- as reasonable an interpretation as any ???
8506 Loc : constant Source_Ptr := Sloc (P);
8507 D : constant Node_Id := Discrete_Range (P);
8511 if Is_Entity_Name (D)
8514 (Type_Low_Bound (Entity (D)),
8515 Type_High_Bound (Entity (D)))
8518 Make_Attribute_Reference (Loc,
8519 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8520 Attribute_Name => Name_First);
8522 elsif Nkind (D) = N_Range
8523 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8525 Lo := Low_Bound (D);
8531 if Present (Lo) then
8533 Make_Indexed_Component (Loc,
8534 Prefix => Relocate_Node (Prefix (P)),
8535 Expressions => New_List (Lo)));
8537 Analyze_And_Resolve (P);
8541 end Address_Attribute;
8547 -- Prefix of the AST_Entry attribute is an entry name which must
8548 -- not be resolved, since this is definitely not an entry call.
8550 when Attribute_AST_Entry =>
8557 -- Prefix of Body_Version attribute can be a subprogram name which
8558 -- must not be resolved, since this is not a call.
8560 when Attribute_Body_Version =>
8567 -- Prefix of Caller attribute is an entry name which must not
8568 -- be resolved, since this is definitely not an entry call.
8570 when Attribute_Caller =>
8577 -- Shares processing with Address attribute
8583 -- If the prefix of the Count attribute is an entry name it must not
8584 -- be resolved, since this is definitely not an entry call. However,
8585 -- if it is an element of an entry family, the index itself may
8586 -- have to be resolved because it can be a general expression.
8588 when Attribute_Count =>
8589 if Nkind (P) = N_Indexed_Component
8590 and then Is_Entity_Name (Prefix (P))
8593 Indx : constant Node_Id := First (Expressions (P));
8594 Fam : constant Entity_Id := Entity (Prefix (P));
8596 Resolve (Indx, Entry_Index_Type (Fam));
8597 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8605 -- Prefix of the Elaborated attribute is a subprogram name which
8606 -- must not be resolved, since this is definitely not a call. Note
8607 -- that it is a library unit, so it cannot be overloaded here.
8609 when Attribute_Elaborated =>
8616 -- Prefix of Enabled attribute is a check name, which must be treated
8617 -- specially and not touched by Resolve.
8619 when Attribute_Enabled =>
8622 --------------------
8623 -- Mechanism_Code --
8624 --------------------
8626 -- Prefix of the Mechanism_Code attribute is a function name
8627 -- which must not be resolved. Should we check for overloaded ???
8629 when Attribute_Mechanism_Code =>
8636 -- Most processing is done in sem_dist, after determining the
8637 -- context type. Node is rewritten as a conversion to a runtime call.
8639 when Attribute_Partition_ID =>
8640 Process_Partition_Id (N);
8647 when Attribute_Pool_Address =>
8654 -- We replace the Range attribute node with a range expression whose
8655 -- bounds are the 'First and 'Last attributes applied to the same
8656 -- prefix. The reason that we do this transformation here instead of
8657 -- in the expander is that it simplifies other parts of the semantic
8658 -- analysis which assume that the Range has been replaced; thus it
8659 -- must be done even when in semantic-only mode (note that the RM
8660 -- specifically mentions this equivalence, we take care that the
8661 -- prefix is only evaluated once).
8663 when Attribute_Range => Range_Attribute :
8669 if not Is_Entity_Name (P)
8670 or else not Is_Type (Entity (P))
8676 Make_Attribute_Reference (Loc,
8678 Duplicate_Subexpr (P, Name_Req => True),
8679 Attribute_Name => Name_Last,
8680 Expressions => Expressions (N));
8683 Make_Attribute_Reference (Loc,
8685 Attribute_Name => Name_First,
8686 Expressions => Expressions (N));
8688 -- If the original was marked as Must_Not_Freeze (see code
8689 -- in Sem_Ch3.Make_Index), then make sure the rewriting
8690 -- does not freeze either.
8692 if Must_Not_Freeze (N) then
8693 Set_Must_Not_Freeze (HB);
8694 Set_Must_Not_Freeze (LB);
8695 Set_Must_Not_Freeze (Prefix (HB));
8696 Set_Must_Not_Freeze (Prefix (LB));
8699 if Raises_Constraint_Error (Prefix (N)) then
8701 -- Preserve Sloc of prefix in the new bounds, so that
8702 -- the posted warning can be removed if we are within
8703 -- unreachable code.
8705 Set_Sloc (LB, Sloc (Prefix (N)));
8706 Set_Sloc (HB, Sloc (Prefix (N)));
8709 Rewrite (N, Make_Range (Loc, LB, HB));
8710 Analyze_And_Resolve (N, Typ);
8712 -- Ensure that the expanded range does not have side effects
8714 Force_Evaluation (LB);
8715 Force_Evaluation (HB);
8717 -- Normally after resolving attribute nodes, Eval_Attribute
8718 -- is called to do any possible static evaluation of the node.
8719 -- However, here since the Range attribute has just been
8720 -- transformed into a range expression it is no longer an
8721 -- attribute node and therefore the call needs to be avoided
8722 -- and is accomplished by simply returning from the procedure.
8725 end Range_Attribute;
8731 -- We will only come here during the prescan of a spec expression
8732 -- containing a Result attribute. In that case the proper Etype has
8733 -- already been set, and nothing more needs to be done here.
8735 when Attribute_Result =>
8742 -- Prefix must not be resolved in this case, since it is not a
8743 -- real entity reference. No action of any kind is require!
8745 when Attribute_UET_Address =>
8748 ----------------------
8749 -- Unchecked_Access --
8750 ----------------------
8752 -- Processing is shared with Access
8754 -------------------------
8755 -- Unrestricted_Access --
8756 -------------------------
8758 -- Processing is shared with Access
8764 -- Apply range check. Note that we did not do this during the
8765 -- analysis phase, since we wanted Eval_Attribute to have a
8766 -- chance at finding an illegal out of range value.
8768 when Attribute_Val =>
8770 -- Note that we do our own Eval_Attribute call here rather than
8771 -- use the common one, because we need to do processing after
8772 -- the call, as per above comment.
8776 -- Eval_Attribute may replace the node with a raise CE, or
8777 -- fold it to a constant. Obviously we only apply a scalar
8778 -- range check if this did not happen!
8780 if Nkind (N) = N_Attribute_Reference
8781 and then Attribute_Name (N) = Name_Val
8783 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
8792 -- Prefix of Version attribute can be a subprogram name which
8793 -- must not be resolved, since this is not a call.
8795 when Attribute_Version =>
8798 ----------------------
8799 -- Other Attributes --
8800 ----------------------
8802 -- For other attributes, resolve prefix unless it is a type. If
8803 -- the attribute reference itself is a type name ('Base and 'Class)
8804 -- then this is only legal within a task or protected record.
8807 if not Is_Entity_Name (P)
8808 or else not Is_Type (Entity (P))
8813 -- If the attribute reference itself is a type name ('Base,
8814 -- 'Class) then this is only legal within a task or protected
8815 -- record. What is this all about ???
8817 if Is_Entity_Name (N)
8818 and then Is_Type (Entity (N))
8820 if Is_Concurrent_Type (Entity (N))
8821 and then In_Open_Scopes (Entity (P))
8826 ("invalid use of subtype name in expression or call", N);
8830 -- For attributes whose argument may be a string, complete
8831 -- resolution of argument now. This avoids premature expansion
8832 -- (and the creation of transient scopes) before the attribute
8833 -- reference is resolved.
8836 when Attribute_Value =>
8837 Resolve (First (Expressions (N)), Standard_String);
8839 when Attribute_Wide_Value =>
8840 Resolve (First (Expressions (N)), Standard_Wide_String);
8842 when Attribute_Wide_Wide_Value =>
8843 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
8845 when others => null;
8848 -- If the prefix of the attribute is a class-wide type then it
8849 -- will be expanded into a dispatching call to a predefined
8850 -- primitive. Therefore we must check for potential violation
8851 -- of such restriction.
8853 if Is_Class_Wide_Type (Etype (P)) then
8854 Check_Restriction (No_Dispatching_Calls, N);
8858 -- Normally the Freezing is done by Resolve but sometimes the Prefix
8859 -- is not resolved, in which case the freezing must be done now.
8861 Freeze_Expression (P);
8863 -- Finally perform static evaluation on the attribute reference
8866 end Resolve_Attribute;
8868 --------------------------------
8869 -- Stream_Attribute_Available --
8870 --------------------------------
8872 function Stream_Attribute_Available
8874 Nam : TSS_Name_Type;
8875 Partial_View : Node_Id := Empty) return Boolean
8877 Etyp : Entity_Id := Typ;
8879 -- Start of processing for Stream_Attribute_Available
8882 -- We need some comments in this body ???
8884 if Has_Stream_Attribute_Definition (Typ, Nam) then
8888 if Is_Class_Wide_Type (Typ) then
8889 return not Is_Limited_Type (Typ)
8890 or else Stream_Attribute_Available (Etype (Typ), Nam);
8893 if Nam = TSS_Stream_Input
8894 and then Is_Abstract_Type (Typ)
8895 and then not Is_Class_Wide_Type (Typ)
8900 if not (Is_Limited_Type (Typ)
8901 or else (Present (Partial_View)
8902 and then Is_Limited_Type (Partial_View)))
8907 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
8909 if Nam = TSS_Stream_Input
8910 and then Ada_Version >= Ada_2005
8911 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
8915 elsif Nam = TSS_Stream_Output
8916 and then Ada_Version >= Ada_2005
8917 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
8922 -- Case of Read and Write: check for attribute definition clause that
8923 -- applies to an ancestor type.
8925 while Etype (Etyp) /= Etyp loop
8926 Etyp := Etype (Etyp);
8928 if Has_Stream_Attribute_Definition (Etyp, Nam) then
8933 if Ada_Version < Ada_2005 then
8935 -- In Ada 95 mode, also consider a non-visible definition
8938 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
8941 and then Stream_Attribute_Available
8942 (Btyp, Nam, Partial_View => Typ);
8947 end Stream_Attribute_Available;