1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, 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_SPARK_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 Restriction_Check_Required (No_Exception_Registration)
1650 and then (Is_RTE (P_Type, RE_Exception_Id)
1652 Is_RTE (P_Type, RE_Exception_Occurrence))
1654 Check_Restriction (No_Exception_Registration, P);
1657 -- Here we must check that the first argument is an access type
1658 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1660 Analyze_And_Resolve (E1);
1663 -- Note: the double call to Root_Type here is needed because the
1664 -- root type of a class-wide type is the corresponding type (e.g.
1665 -- X for X'Class, and we really want to go to the root.)
1667 if not Is_Access_Type (Etyp)
1668 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1669 RTE (RE_Root_Stream_Type)
1672 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1675 -- Check that the second argument is of the right type if there is
1676 -- one (the Input attribute has only one argument so this is skipped)
1678 if Present (E2) then
1681 if Nam = TSS_Stream_Read
1682 and then not Is_OK_Variable_For_Out_Formal (E2)
1685 ("second argument of % attribute must be a variable", E2);
1688 Resolve (E2, P_Type);
1692 end Check_Stream_Attribute;
1694 -----------------------
1695 -- Check_Task_Prefix --
1696 -----------------------
1698 procedure Check_Task_Prefix is
1702 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1703 -- task interface class-wide types.
1705 if Is_Task_Type (Etype (P))
1706 or else (Is_Access_Type (Etype (P))
1707 and then Is_Task_Type (Designated_Type (Etype (P))))
1708 or else (Ada_Version >= Ada_2005
1709 and then Ekind (Etype (P)) = E_Class_Wide_Type
1710 and then Is_Interface (Etype (P))
1711 and then Is_Task_Interface (Etype (P)))
1716 if Ada_Version >= Ada_2005 then
1718 ("prefix of % attribute must be a task or a task " &
1719 "interface class-wide object");
1722 Error_Attr_P ("prefix of % attribute must be a task");
1725 end Check_Task_Prefix;
1731 -- The possibilities are an entity name denoting a type, or an
1732 -- attribute reference that denotes a type (Base or Class). If
1733 -- the type is incomplete, replace it with its full view.
1735 procedure Check_Type is
1737 if not Is_Entity_Name (P)
1738 or else not Is_Type (Entity (P))
1740 Error_Attr_P ("prefix of % attribute must be a type");
1742 elsif Is_Protected_Self_Reference (P) then
1744 ("prefix of % attribute denotes current instance "
1745 & "(RM 9.4(21/2))");
1747 elsif Ekind (Entity (P)) = E_Incomplete_Type
1748 and then Present (Full_View (Entity (P)))
1750 P_Type := Full_View (Entity (P));
1751 Set_Entity (P, P_Type);
1755 ---------------------
1756 -- Check_Unit_Name --
1757 ---------------------
1759 procedure Check_Unit_Name (Nod : Node_Id) is
1761 if Nkind (Nod) = N_Identifier then
1764 elsif Nkind (Nod) = N_Selected_Component then
1765 Check_Unit_Name (Prefix (Nod));
1767 if Nkind (Selector_Name (Nod)) = N_Identifier then
1772 Error_Attr ("argument for % attribute must be unit name", P);
1773 end Check_Unit_Name;
1779 procedure Error_Attr is
1781 Set_Etype (N, Any_Type);
1782 Set_Entity (N, Any_Type);
1783 raise Bad_Attribute;
1786 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1788 Error_Msg_Name_1 := Aname;
1789 Error_Msg_N (Msg, Error_Node);
1797 procedure Error_Attr_P (Msg : String) is
1799 Error_Msg_Name_1 := Aname;
1800 Error_Msg_F (Msg, P);
1804 ----------------------------
1805 -- Legal_Formal_Attribute --
1806 ----------------------------
1808 procedure Legal_Formal_Attribute is
1812 if not Is_Entity_Name (P)
1813 or else not Is_Type (Entity (P))
1815 Error_Attr_P ("prefix of % attribute must be generic type");
1817 elsif Is_Generic_Actual_Type (Entity (P))
1819 or else In_Inlined_Body
1823 elsif Is_Generic_Type (Entity (P)) then
1824 if not Is_Indefinite_Subtype (Entity (P)) then
1826 ("prefix of % attribute must be indefinite generic type");
1831 ("prefix of % attribute must be indefinite generic type");
1834 Set_Etype (N, Standard_Boolean);
1835 end Legal_Formal_Attribute;
1837 ------------------------
1838 -- Standard_Attribute --
1839 ------------------------
1841 procedure Standard_Attribute (Val : Int) is
1843 Check_Standard_Prefix;
1844 Rewrite (N, Make_Integer_Literal (Loc, Val));
1846 end Standard_Attribute;
1848 -------------------------
1849 -- Unexpected Argument --
1850 -------------------------
1852 procedure Unexpected_Argument (En : Node_Id) is
1854 Error_Attr ("unexpected argument for % attribute", En);
1855 end Unexpected_Argument;
1857 -------------------------------------------------
1858 -- Validate_Non_Static_Attribute_Function_Call --
1859 -------------------------------------------------
1861 -- This function should be moved to Sem_Dist ???
1863 procedure Validate_Non_Static_Attribute_Function_Call is
1865 if In_Preelaborated_Unit
1866 and then not In_Subprogram_Or_Concurrent_Unit
1868 Flag_Non_Static_Expr
1869 ("non-static function call in preelaborated unit!", N);
1871 end Validate_Non_Static_Attribute_Function_Call;
1873 -- Start of processing for Analyze_Attribute
1876 -- Immediate return if unrecognized attribute (already diagnosed
1877 -- by parser, so there is nothing more that we need to do)
1879 if not Is_Attribute_Name (Aname) then
1880 raise Bad_Attribute;
1883 -- Deal with Ada 83 issues
1885 if Comes_From_Source (N) then
1886 if not Attribute_83 (Attr_Id) then
1887 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1888 Error_Msg_Name_1 := Aname;
1889 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1892 if Attribute_Impl_Def (Attr_Id) then
1893 Check_Restriction (No_Implementation_Attributes, N);
1898 -- Deal with Ada 2005 attributes that are
1900 if Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005 then
1901 Check_Restriction (No_Implementation_Attributes, N);
1904 -- Remote access to subprogram type access attribute reference needs
1905 -- unanalyzed copy for tree transformation. The analyzed copy is used
1906 -- for its semantic information (whether prefix is a remote subprogram
1907 -- name), the unanalyzed copy is used to construct new subtree rooted
1908 -- with N_Aggregate which represents a fat pointer aggregate.
1910 if Aname = Name_Access then
1911 Discard_Node (Copy_Separate_Tree (N));
1914 -- Analyze prefix and exit if error in analysis. If the prefix is an
1915 -- incomplete type, use full view if available. Note that there are
1916 -- some attributes for which we do not analyze the prefix, since the
1917 -- prefix is not a normal name.
1919 if Aname /= Name_Elab_Body
1921 Aname /= Name_Elab_Spec
1923 Aname /= Name_UET_Address
1925 Aname /= Name_Enabled
1928 P_Type := Etype (P);
1930 if Is_Entity_Name (P)
1931 and then Present (Entity (P))
1932 and then Is_Type (Entity (P))
1934 if Ekind (Entity (P)) = E_Incomplete_Type then
1935 P_Type := Get_Full_View (P_Type);
1936 Set_Entity (P, P_Type);
1937 Set_Etype (P, P_Type);
1939 elsif Entity (P) = Current_Scope
1940 and then Is_Record_Type (Entity (P))
1942 -- Use of current instance within the type. Verify that if the
1943 -- attribute appears within a constraint, it yields an access
1944 -- type, other uses are illegal.
1952 and then Nkind (Parent (Par)) /= N_Component_Definition
1954 Par := Parent (Par);
1958 and then Nkind (Par) = N_Subtype_Indication
1960 if Attr_Id /= Attribute_Access
1961 and then Attr_Id /= Attribute_Unchecked_Access
1962 and then Attr_Id /= Attribute_Unrestricted_Access
1965 ("in a constraint the current instance can only"
1966 & " be used with an access attribute", N);
1973 if P_Type = Any_Type then
1974 raise Bad_Attribute;
1977 P_Base_Type := Base_Type (P_Type);
1980 -- Analyze expressions that may be present, exiting if an error occurs
1987 E1 := First (Exprs);
1990 -- Check for missing/bad expression (result of previous error)
1992 if No (E1) or else Etype (E1) = Any_Type then
1993 raise Bad_Attribute;
1998 if Present (E2) then
2001 if Etype (E2) = Any_Type then
2002 raise Bad_Attribute;
2005 if Present (Next (E2)) then
2006 Unexpected_Argument (Next (E2));
2011 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
2012 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
2014 if Ada_Version < Ada_2005
2015 and then Is_Overloaded (P)
2016 and then Aname /= Name_Access
2017 and then Aname /= Name_Address
2018 and then Aname /= Name_Code_Address
2019 and then Aname /= Name_Count
2020 and then Aname /= Name_Result
2021 and then Aname /= Name_Unchecked_Access
2023 Error_Attr ("ambiguous prefix for % attribute", P);
2025 elsif Ada_Version >= Ada_2005
2026 and then Is_Overloaded (P)
2027 and then Aname /= Name_Access
2028 and then Aname /= Name_Address
2029 and then Aname /= Name_Code_Address
2030 and then Aname /= Name_Result
2031 and then Aname /= Name_Unchecked_Access
2033 -- Ada 2005 (AI-345): Since protected and task types have primitive
2034 -- entry wrappers, the attributes Count, Caller and AST_Entry require
2037 if Ada_Version >= Ada_2005
2038 and then (Aname = Name_Count
2039 or else Aname = Name_Caller
2040 or else Aname = Name_AST_Entry)
2043 Count : Natural := 0;
2048 Get_First_Interp (P, I, It);
2049 while Present (It.Nam) loop
2050 if Comes_From_Source (It.Nam) then
2056 Get_Next_Interp (I, It);
2060 Error_Attr ("ambiguous prefix for % attribute", P);
2062 Set_Is_Overloaded (P, False);
2067 Error_Attr ("ambiguous prefix for % attribute", P);
2071 -- In SPARK, attributes of private types are only allowed if the full
2072 -- type declaration is visible.
2074 if Is_Entity_Name (P)
2075 and then Present (Entity (P)) -- needed in some cases
2076 and then Is_Type (Entity (P))
2077 and then Is_Private_Type (P_Type)
2078 and then not In_Open_Scopes (Scope (P_Type))
2079 and then not In_Spec_Expression
2081 Error_Msg_Node_1 := First_Subtype (P_Type);
2082 Check_SPARK_Restriction ("invisible attribute of}", N);
2085 -- Remaining processing depends on attribute
2093 when Attribute_Abort_Signal =>
2094 Check_Standard_Prefix;
2095 Rewrite (N, New_Reference_To (Stand.Abort_Signal, Loc));
2102 when Attribute_Access =>
2103 Analyze_Access_Attribute;
2109 when Attribute_Address =>
2112 -- Check for some junk cases, where we have to allow the address
2113 -- attribute but it does not make much sense, so at least for now
2114 -- just replace with Null_Address.
2116 -- We also do this if the prefix is a reference to the AST_Entry
2117 -- attribute. If expansion is active, the attribute will be
2118 -- replaced by a function call, and address will work fine and
2119 -- get the proper value, but if expansion is not active, then
2120 -- the check here allows proper semantic analysis of the reference.
2122 -- An Address attribute created by expansion is legal even when it
2123 -- applies to other entity-denoting expressions.
2125 if Is_Protected_Self_Reference (P) then
2127 -- Address attribute on a protected object self reference is legal
2131 elsif Is_Entity_Name (P) then
2133 Ent : constant Entity_Id := Entity (P);
2136 if Is_Subprogram (Ent) then
2137 Set_Address_Taken (Ent);
2138 Kill_Current_Values (Ent);
2140 -- An Address attribute is accepted when generated by the
2141 -- compiler for dispatching operation, and an error is
2142 -- issued once the subprogram is frozen (to avoid confusing
2143 -- errors about implicit uses of Address in the dispatch
2144 -- table initialization).
2146 if Has_Pragma_Inline_Always (Entity (P))
2147 and then Comes_From_Source (P)
2150 ("prefix of % attribute cannot be Inline_Always" &
2153 -- It is illegal to apply 'Address to an intrinsic
2154 -- subprogram. This is now formalized in AI05-0095.
2155 -- In an instance, an attempt to obtain 'Address of an
2156 -- intrinsic subprogram (e.g the renaming of a predefined
2157 -- operator that is an actual) raises Program_Error.
2159 elsif Convention (Ent) = Convention_Intrinsic then
2162 Make_Raise_Program_Error (Loc,
2163 Reason => PE_Address_Of_Intrinsic));
2167 ("cannot take Address of intrinsic subprogram", N);
2170 -- Issue an error if prefix denotes an eliminated subprogram
2173 Check_For_Eliminated_Subprogram (P, Ent);
2176 elsif Is_Object (Ent)
2177 or else Ekind (Ent) = E_Label
2179 Set_Address_Taken (Ent);
2181 -- If we have an address of an object, and the attribute
2182 -- comes from source, then set the object as potentially
2183 -- source modified. We do this because the resulting address
2184 -- can potentially be used to modify the variable and we
2185 -- might not detect this, leading to some junk warnings.
2187 Set_Never_Set_In_Source (Ent, False);
2189 elsif (Is_Concurrent_Type (Etype (Ent))
2190 and then Etype (Ent) = Base_Type (Ent))
2191 or else Ekind (Ent) = E_Package
2192 or else Is_Generic_Unit (Ent)
2195 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2198 Error_Attr ("invalid prefix for % attribute", P);
2202 elsif Nkind (P) = N_Attribute_Reference
2203 and then Attribute_Name (P) = Name_AST_Entry
2206 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2208 elsif Is_Object_Reference (P) then
2211 elsif Nkind (P) = N_Selected_Component
2212 and then Is_Subprogram (Entity (Selector_Name (P)))
2216 -- What exactly are we allowing here ??? and is this properly
2217 -- documented in the sinfo documentation for this node ???
2219 elsif not Comes_From_Source (N) then
2223 Error_Attr ("invalid prefix for % attribute", P);
2226 Set_Etype (N, RTE (RE_Address));
2232 when Attribute_Address_Size =>
2233 Standard_Attribute (System_Address_Size);
2239 when Attribute_Adjacent =>
2240 Check_Floating_Point_Type_2;
2241 Set_Etype (N, P_Base_Type);
2242 Resolve (E1, P_Base_Type);
2243 Resolve (E2, P_Base_Type);
2249 when Attribute_Aft =>
2250 Check_Fixed_Point_Type_0;
2251 Set_Etype (N, Universal_Integer);
2257 when Attribute_Alignment =>
2259 -- Don't we need more checking here, cf Size ???
2262 Check_Not_Incomplete_Type;
2264 Set_Etype (N, Universal_Integer);
2270 when Attribute_Asm_Input =>
2271 Check_Asm_Attribute;
2273 -- The back-end may need to take the address of E2
2275 if Is_Entity_Name (E2) then
2276 Set_Address_Taken (Entity (E2));
2279 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2285 when Attribute_Asm_Output =>
2286 Check_Asm_Attribute;
2288 if Etype (E2) = Any_Type then
2291 elsif Aname = Name_Asm_Output then
2292 if not Is_Variable (E2) then
2294 ("second argument for Asm_Output is not variable", E2);
2298 Note_Possible_Modification (E2, Sure => True);
2300 -- The back-end may need to take the address of E2
2302 if Is_Entity_Name (E2) then
2303 Set_Address_Taken (Entity (E2));
2306 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2312 when Attribute_AST_Entry => AST_Entry : declare
2318 -- Indicates if entry family index is present. Note the coding
2319 -- here handles the entry family case, but in fact it cannot be
2320 -- executed currently, because pragma AST_Entry does not permit
2321 -- the specification of an entry family.
2323 procedure Bad_AST_Entry;
2324 -- Signal a bad AST_Entry pragma
2326 function OK_Entry (E : Entity_Id) return Boolean;
2327 -- Checks that E is of an appropriate entity kind for an entry
2328 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2329 -- is set True for the entry family case). In the True case,
2330 -- makes sure that Is_AST_Entry is set on the entry.
2336 procedure Bad_AST_Entry is
2338 Error_Attr_P ("prefix for % attribute must be task entry");
2345 function OK_Entry (E : Entity_Id) return Boolean is
2350 Result := (Ekind (E) = E_Entry_Family);
2352 Result := (Ekind (E) = E_Entry);
2356 if not Is_AST_Entry (E) then
2357 Error_Msg_Name_2 := Aname;
2358 Error_Attr ("% attribute requires previous % pragma", P);
2365 -- Start of processing for AST_Entry
2371 -- Deal with entry family case
2373 if Nkind (P) = N_Indexed_Component then
2381 Ptyp := Etype (Pref);
2383 if Ptyp = Any_Type or else Error_Posted (Pref) then
2387 -- If the prefix is a selected component whose prefix is of an
2388 -- access type, then introduce an explicit dereference.
2389 -- ??? Could we reuse Check_Dereference here?
2391 if Nkind (Pref) = N_Selected_Component
2392 and then Is_Access_Type (Ptyp)
2395 Make_Explicit_Dereference (Sloc (Pref),
2396 Relocate_Node (Pref)));
2397 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2400 -- Prefix can be of the form a.b, where a is a task object
2401 -- and b is one of the entries of the corresponding task type.
2403 if Nkind (Pref) = N_Selected_Component
2404 and then OK_Entry (Entity (Selector_Name (Pref)))
2405 and then Is_Object_Reference (Prefix (Pref))
2406 and then Is_Task_Type (Etype (Prefix (Pref)))
2410 -- Otherwise the prefix must be an entry of a containing task,
2411 -- or of a variable of the enclosing task type.
2414 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2415 Ent := Entity (Pref);
2417 if not OK_Entry (Ent)
2418 or else not In_Open_Scopes (Scope (Ent))
2428 Set_Etype (N, RTE (RE_AST_Handler));
2435 -- Note: when the base attribute appears in the context of a subtype
2436 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2437 -- the following circuit.
2439 when Attribute_Base => Base : declare
2447 if Ada_Version >= Ada_95
2448 and then not Is_Scalar_Type (Typ)
2449 and then not Is_Generic_Type (Typ)
2451 Error_Attr_P ("prefix of Base attribute must be scalar type");
2453 elsif Sloc (Typ) = Standard_Location
2454 and then Base_Type (Typ) = Typ
2455 and then Warn_On_Redundant_Constructs
2457 Error_Msg_NE -- CODEFIX
2458 ("?redundant attribute, & is its own base type", N, Typ);
2461 if Nkind (Parent (N)) /= N_Attribute_Reference then
2462 Error_Msg_Name_1 := Aname;
2463 Check_SPARK_Restriction
2464 ("attribute% is only allowed as prefix of another attribute", P);
2467 Set_Etype (N, Base_Type (Entity (P)));
2468 Set_Entity (N, Base_Type (Entity (P)));
2469 Rewrite (N, New_Reference_To (Entity (N), Loc));
2477 when Attribute_Bit => Bit :
2481 if not Is_Object_Reference (P) then
2482 Error_Attr_P ("prefix for % attribute must be object");
2484 -- What about the access object cases ???
2490 Set_Etype (N, Universal_Integer);
2497 when Attribute_Bit_Order => Bit_Order :
2502 if not Is_Record_Type (P_Type) then
2503 Error_Attr_P ("prefix of % attribute must be record type");
2506 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2508 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2511 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2514 Set_Etype (N, RTE (RE_Bit_Order));
2517 -- Reset incorrect indication of staticness
2519 Set_Is_Static_Expression (N, False);
2526 -- Note: in generated code, we can have a Bit_Position attribute
2527 -- applied to a (naked) record component (i.e. the prefix is an
2528 -- identifier that references an E_Component or E_Discriminant
2529 -- entity directly, and this is interpreted as expected by Gigi.
2530 -- The following code will not tolerate such usage, but when the
2531 -- expander creates this special case, it marks it as analyzed
2532 -- immediately and sets an appropriate type.
2534 when Attribute_Bit_Position =>
2535 if Comes_From_Source (N) then
2539 Set_Etype (N, Universal_Integer);
2545 when Attribute_Body_Version =>
2548 Set_Etype (N, RTE (RE_Version_String));
2554 when Attribute_Callable =>
2556 Set_Etype (N, Standard_Boolean);
2563 when Attribute_Caller => Caller : declare
2570 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2573 if not Is_Entry (Ent) then
2574 Error_Attr ("invalid entry name", N);
2578 Error_Attr ("invalid entry name", N);
2582 for J in reverse 0 .. Scope_Stack.Last loop
2583 S := Scope_Stack.Table (J).Entity;
2585 if S = Scope (Ent) then
2586 Error_Attr ("Caller must appear in matching accept or body", N);
2592 Set_Etype (N, RTE (RO_AT_Task_Id));
2599 when Attribute_Ceiling =>
2600 Check_Floating_Point_Type_1;
2601 Set_Etype (N, P_Base_Type);
2602 Resolve (E1, P_Base_Type);
2608 when Attribute_Class =>
2609 Check_Restriction (No_Dispatch, N);
2613 -- Applying Class to untagged incomplete type is obsolescent in Ada
2614 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
2615 -- this flag gets set by Find_Type in this situation.
2617 if Restriction_Check_Required (No_Obsolescent_Features)
2618 and then Ada_Version >= Ada_2005
2619 and then Ekind (P_Type) = E_Incomplete_Type
2622 DN : constant Node_Id := Declaration_Node (P_Type);
2624 if Nkind (DN) = N_Incomplete_Type_Declaration
2625 and then not Tagged_Present (DN)
2627 Check_Restriction (No_Obsolescent_Features, P);
2636 when Attribute_Code_Address =>
2639 if Nkind (P) = N_Attribute_Reference
2640 and then (Attribute_Name (P) = Name_Elab_Body
2642 Attribute_Name (P) = Name_Elab_Spec)
2646 elsif not Is_Entity_Name (P)
2647 or else (Ekind (Entity (P)) /= E_Function
2649 Ekind (Entity (P)) /= E_Procedure)
2651 Error_Attr ("invalid prefix for % attribute", P);
2652 Set_Address_Taken (Entity (P));
2654 -- Issue an error if the prefix denotes an eliminated subprogram
2657 Check_For_Eliminated_Subprogram (P, Entity (P));
2660 Set_Etype (N, RTE (RE_Address));
2662 ----------------------
2663 -- Compiler_Version --
2664 ----------------------
2666 when Attribute_Compiler_Version =>
2668 Check_Standard_Prefix;
2669 Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
2670 Analyze_And_Resolve (N, Standard_String);
2672 --------------------
2673 -- Component_Size --
2674 --------------------
2676 when Attribute_Component_Size =>
2678 Set_Etype (N, Universal_Integer);
2680 -- Note: unlike other array attributes, unconstrained arrays are OK
2682 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2692 when Attribute_Compose =>
2693 Check_Floating_Point_Type_2;
2694 Set_Etype (N, P_Base_Type);
2695 Resolve (E1, P_Base_Type);
2696 Resolve (E2, Any_Integer);
2702 when Attribute_Constrained =>
2704 Set_Etype (N, Standard_Boolean);
2706 -- Case from RM J.4(2) of constrained applied to private type
2708 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2709 Check_Restriction (No_Obsolescent_Features, P);
2711 if Warn_On_Obsolescent_Feature then
2713 ("constrained for private type is an " &
2714 "obsolescent feature (RM J.4)?", N);
2717 -- If we are within an instance, the attribute must be legal
2718 -- because it was valid in the generic unit. Ditto if this is
2719 -- an inlining of a function declared in an instance.
2722 or else In_Inlined_Body
2726 -- For sure OK if we have a real private type itself, but must
2727 -- be completed, cannot apply Constrained to incomplete type.
2729 elsif Is_Private_Type (Entity (P)) then
2731 -- Note: this is one of the Annex J features that does not
2732 -- generate a warning from -gnatwj, since in fact it seems
2733 -- very useful, and is used in the GNAT runtime.
2735 Check_Not_Incomplete_Type;
2739 -- Normal (non-obsolescent case) of application to object of
2740 -- a discriminated type.
2743 Check_Object_Reference (P);
2745 -- If N does not come from source, then we allow the
2746 -- the attribute prefix to be of a private type whose
2747 -- full type has discriminants. This occurs in cases
2748 -- involving expanded calls to stream attributes.
2750 if not Comes_From_Source (N) then
2751 P_Type := Underlying_Type (P_Type);
2754 -- Must have discriminants or be an access type designating
2755 -- a type with discriminants. If it is a classwide type is ???
2756 -- has unknown discriminants.
2758 if Has_Discriminants (P_Type)
2759 or else Has_Unknown_Discriminants (P_Type)
2761 (Is_Access_Type (P_Type)
2762 and then Has_Discriminants (Designated_Type (P_Type)))
2766 -- Also allow an object of a generic type if extensions allowed
2767 -- and allow this for any type at all.
2769 elsif (Is_Generic_Type (P_Type)
2770 or else Is_Generic_Actual_Type (P_Type))
2771 and then Extensions_Allowed
2777 -- Fall through if bad prefix
2780 ("prefix of % attribute must be object of discriminated type");
2786 when Attribute_Copy_Sign =>
2787 Check_Floating_Point_Type_2;
2788 Set_Etype (N, P_Base_Type);
2789 Resolve (E1, P_Base_Type);
2790 Resolve (E2, P_Base_Type);
2796 when Attribute_Count => Count :
2805 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2808 if Ekind (Ent) /= E_Entry then
2809 Error_Attr ("invalid entry name", N);
2812 elsif Nkind (P) = N_Indexed_Component then
2813 if not Is_Entity_Name (Prefix (P))
2814 or else No (Entity (Prefix (P)))
2815 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2817 if Nkind (Prefix (P)) = N_Selected_Component
2818 and then Present (Entity (Selector_Name (Prefix (P))))
2819 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2823 ("attribute % must apply to entry of current task", P);
2826 Error_Attr ("invalid entry family name", P);
2831 Ent := Entity (Prefix (P));
2834 elsif Nkind (P) = N_Selected_Component
2835 and then Present (Entity (Selector_Name (P)))
2836 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2839 ("attribute % must apply to entry of current task", P);
2842 Error_Attr ("invalid entry name", N);
2846 for J in reverse 0 .. Scope_Stack.Last loop
2847 S := Scope_Stack.Table (J).Entity;
2849 if S = Scope (Ent) then
2850 if Nkind (P) = N_Expanded_Name then
2851 Tsk := Entity (Prefix (P));
2853 -- The prefix denotes either the task type, or else a
2854 -- single task whose task type is being analyzed.
2859 or else (not Is_Type (Tsk)
2860 and then Etype (Tsk) = S
2861 and then not (Comes_From_Source (S)))
2866 ("Attribute % must apply to entry of current task", N);
2872 elsif Ekind (Scope (Ent)) in Task_Kind
2874 not Ekind_In (S, E_Loop, E_Block, E_Entry, E_Entry_Family)
2876 Error_Attr ("Attribute % cannot appear in inner unit", N);
2878 elsif Ekind (Scope (Ent)) = E_Protected_Type
2879 and then not Has_Completion (Scope (Ent))
2881 Error_Attr ("attribute % can only be used inside body", N);
2885 if Is_Overloaded (P) then
2887 Index : Interp_Index;
2891 Get_First_Interp (P, Index, It);
2893 while Present (It.Nam) loop
2894 if It.Nam = Ent then
2897 -- Ada 2005 (AI-345): Do not consider primitive entry
2898 -- wrappers generated for task or protected types.
2900 elsif Ada_Version >= Ada_2005
2901 and then not Comes_From_Source (It.Nam)
2906 Error_Attr ("ambiguous entry name", N);
2909 Get_Next_Interp (Index, It);
2914 Set_Etype (N, Universal_Integer);
2917 -----------------------
2918 -- Default_Bit_Order --
2919 -----------------------
2921 when Attribute_Default_Bit_Order => Default_Bit_Order :
2923 Check_Standard_Prefix;
2925 if Bytes_Big_Endian then
2927 Make_Integer_Literal (Loc, False_Value));
2930 Make_Integer_Literal (Loc, True_Value));
2933 Set_Etype (N, Universal_Integer);
2934 Set_Is_Static_Expression (N);
2935 end Default_Bit_Order;
2941 when Attribute_Definite =>
2942 Legal_Formal_Attribute;
2948 when Attribute_Delta =>
2949 Check_Fixed_Point_Type_0;
2950 Set_Etype (N, Universal_Real);
2956 when Attribute_Denorm =>
2957 Check_Floating_Point_Type_0;
2958 Set_Etype (N, Standard_Boolean);
2964 when Attribute_Digits =>
2968 if not Is_Floating_Point_Type (P_Type)
2969 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2972 ("prefix of % attribute must be float or decimal type");
2975 Set_Etype (N, Universal_Integer);
2981 -- Also handles processing for Elab_Spec
2983 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2985 Check_Unit_Name (P);
2986 Set_Etype (N, Standard_Void_Type);
2988 -- We have to manually call the expander in this case to get
2989 -- the necessary expansion (normally attributes that return
2990 -- entities are not expanded).
2998 -- Shares processing with Elab_Body
3004 when Attribute_Elaborated =>
3007 Set_Etype (N, Standard_Boolean);
3013 when Attribute_Emax =>
3014 Check_Floating_Point_Type_0;
3015 Set_Etype (N, Universal_Integer);
3021 when Attribute_Enabled =>
3022 Check_Either_E0_Or_E1;
3024 if Present (E1) then
3025 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
3026 Error_Msg_N ("entity name expected for Enabled attribute", E1);
3031 if Nkind (P) /= N_Identifier then
3032 Error_Msg_N ("identifier expected (check name)", P);
3033 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
3034 Error_Msg_N ("& is not a recognized check name", P);
3037 Set_Etype (N, Standard_Boolean);
3043 when Attribute_Enum_Rep => Enum_Rep : declare
3045 if Present (E1) then
3047 Check_Discrete_Type;
3048 Resolve (E1, P_Base_Type);
3051 if not Is_Entity_Name (P)
3052 or else (not Is_Object (Entity (P))
3054 Ekind (Entity (P)) /= E_Enumeration_Literal)
3057 ("prefix of % attribute must be " &
3058 "discrete type/object or enum literal");
3062 Set_Etype (N, Universal_Integer);
3069 when Attribute_Enum_Val => Enum_Val : begin
3073 if not Is_Enumeration_Type (P_Type) then
3074 Error_Attr_P ("prefix of % attribute must be enumeration type");
3077 -- If the enumeration type has a standard representation, the effect
3078 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3080 if not Has_Non_Standard_Rep (P_Base_Type) then
3082 Make_Attribute_Reference (Loc,
3083 Prefix => Relocate_Node (Prefix (N)),
3084 Attribute_Name => Name_Val,
3085 Expressions => New_List (Relocate_Node (E1))));
3086 Analyze_And_Resolve (N, P_Base_Type);
3088 -- Non-standard representation case (enumeration with holes)
3092 Resolve (E1, Any_Integer);
3093 Set_Etype (N, P_Base_Type);
3101 when Attribute_Epsilon =>
3102 Check_Floating_Point_Type_0;
3103 Set_Etype (N, Universal_Real);
3109 when Attribute_Exponent =>
3110 Check_Floating_Point_Type_1;
3111 Set_Etype (N, Universal_Integer);
3112 Resolve (E1, P_Base_Type);
3118 when Attribute_External_Tag =>
3122 Set_Etype (N, Standard_String);
3124 if not Is_Tagged_Type (P_Type) then
3125 Error_Attr_P ("prefix of % attribute must be tagged");
3132 when Attribute_Fast_Math =>
3133 Check_Standard_Prefix;
3135 if Opt.Fast_Math then
3136 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
3138 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
3145 when Attribute_First =>
3146 Check_Array_Or_Scalar_Type;
3147 Bad_Attribute_For_Predicate;
3153 when Attribute_First_Bit =>
3155 Set_Etype (N, Universal_Integer);
3161 when Attribute_Fixed_Value =>
3163 Check_Fixed_Point_Type;
3164 Resolve (E1, Any_Integer);
3165 Set_Etype (N, P_Base_Type);
3171 when Attribute_Floor =>
3172 Check_Floating_Point_Type_1;
3173 Set_Etype (N, P_Base_Type);
3174 Resolve (E1, P_Base_Type);
3180 when Attribute_Fore =>
3181 Check_Fixed_Point_Type_0;
3182 Set_Etype (N, Universal_Integer);
3188 when Attribute_Fraction =>
3189 Check_Floating_Point_Type_1;
3190 Set_Etype (N, P_Base_Type);
3191 Resolve (E1, P_Base_Type);
3197 when Attribute_From_Any =>
3199 Check_PolyORB_Attribute;
3200 Set_Etype (N, P_Base_Type);
3202 -----------------------
3203 -- Has_Access_Values --
3204 -----------------------
3206 when Attribute_Has_Access_Values =>
3209 Set_Etype (N, Standard_Boolean);
3211 -----------------------
3212 -- Has_Tagged_Values --
3213 -----------------------
3215 when Attribute_Has_Tagged_Values =>
3218 Set_Etype (N, Standard_Boolean);
3220 -----------------------
3221 -- Has_Discriminants --
3222 -----------------------
3224 when Attribute_Has_Discriminants =>
3225 Legal_Formal_Attribute;
3231 when Attribute_Identity =>
3235 if Etype (P) = Standard_Exception_Type then
3236 Set_Etype (N, RTE (RE_Exception_Id));
3238 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3239 -- task interface class-wide types.
3241 elsif Is_Task_Type (Etype (P))
3242 or else (Is_Access_Type (Etype (P))
3243 and then Is_Task_Type (Designated_Type (Etype (P))))
3244 or else (Ada_Version >= Ada_2005
3245 and then Ekind (Etype (P)) = E_Class_Wide_Type
3246 and then Is_Interface (Etype (P))
3247 and then Is_Task_Interface (Etype (P)))
3250 Set_Etype (N, RTE (RO_AT_Task_Id));
3253 if Ada_Version >= Ada_2005 then
3255 ("prefix of % attribute must be an exception, a " &
3256 "task or a task interface class-wide object");
3259 ("prefix of % attribute must be a task or an exception");
3267 when Attribute_Image => Image :
3269 Check_Formal_Restriction_On_Attribute;
3271 Set_Etype (N, Standard_String);
3273 if Is_Real_Type (P_Type) then
3274 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3275 Error_Msg_Name_1 := Aname;
3277 ("(Ada 83) % attribute not allowed for real types", N);
3281 if Is_Enumeration_Type (P_Type) then
3282 Check_Restriction (No_Enumeration_Maps, N);
3286 Resolve (E1, P_Base_Type);
3288 Validate_Non_Static_Attribute_Function_Call;
3295 when Attribute_Img => Img :
3298 Set_Etype (N, Standard_String);
3300 if not Is_Scalar_Type (P_Type)
3301 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3304 ("prefix of % attribute must be scalar object name");
3314 when Attribute_Input =>
3316 Check_Stream_Attribute (TSS_Stream_Input);
3317 Set_Etype (N, P_Base_Type);
3323 when Attribute_Integer_Value =>
3326 Resolve (E1, Any_Fixed);
3328 -- Signal an error if argument type is not a specific fixed-point
3329 -- subtype. An error has been signalled already if the argument
3330 -- was not of a fixed-point type.
3332 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3333 Error_Attr ("argument of % must be of a fixed-point type", E1);
3336 Set_Etype (N, P_Base_Type);
3342 when Attribute_Invalid_Value =>
3345 Set_Etype (N, P_Base_Type);
3346 Invalid_Value_Used := True;
3352 when Attribute_Large =>
3355 Set_Etype (N, Universal_Real);
3361 when Attribute_Last =>
3362 Check_Array_Or_Scalar_Type;
3363 Bad_Attribute_For_Predicate;
3369 when Attribute_Last_Bit =>
3371 Set_Etype (N, Universal_Integer);
3377 when Attribute_Leading_Part =>
3378 Check_Floating_Point_Type_2;
3379 Set_Etype (N, P_Base_Type);
3380 Resolve (E1, P_Base_Type);
3381 Resolve (E2, Any_Integer);
3387 when Attribute_Length =>
3389 Set_Etype (N, Universal_Integer);
3395 when Attribute_Machine =>
3396 Check_Floating_Point_Type_1;
3397 Set_Etype (N, P_Base_Type);
3398 Resolve (E1, P_Base_Type);
3404 when Attribute_Machine_Emax =>
3405 Check_Floating_Point_Type_0;
3406 Set_Etype (N, Universal_Integer);
3412 when Attribute_Machine_Emin =>
3413 Check_Floating_Point_Type_0;
3414 Set_Etype (N, Universal_Integer);
3416 ----------------------
3417 -- Machine_Mantissa --
3418 ----------------------
3420 when Attribute_Machine_Mantissa =>
3421 Check_Floating_Point_Type_0;
3422 Set_Etype (N, Universal_Integer);
3424 -----------------------
3425 -- Machine_Overflows --
3426 -----------------------
3428 when Attribute_Machine_Overflows =>
3431 Set_Etype (N, Standard_Boolean);
3437 when Attribute_Machine_Radix =>
3440 Set_Etype (N, Universal_Integer);
3442 ----------------------
3443 -- Machine_Rounding --
3444 ----------------------
3446 when Attribute_Machine_Rounding =>
3447 Check_Floating_Point_Type_1;
3448 Set_Etype (N, P_Base_Type);
3449 Resolve (E1, P_Base_Type);
3451 --------------------
3452 -- Machine_Rounds --
3453 --------------------
3455 when Attribute_Machine_Rounds =>
3458 Set_Etype (N, Standard_Boolean);
3464 when Attribute_Machine_Size =>
3467 Check_Not_Incomplete_Type;
3468 Set_Etype (N, Universal_Integer);
3474 when Attribute_Mantissa =>
3477 Set_Etype (N, Universal_Integer);
3483 when Attribute_Max =>
3486 Resolve (E1, P_Base_Type);
3487 Resolve (E2, P_Base_Type);
3488 Set_Etype (N, P_Base_Type);
3490 ----------------------------------
3491 -- Max_Alignment_For_Allocation --
3492 -- Max_Size_In_Storage_Elements --
3493 ----------------------------------
3495 when Attribute_Max_Alignment_For_Allocation |
3496 Attribute_Max_Size_In_Storage_Elements =>
3499 Check_Not_Incomplete_Type;
3500 Set_Etype (N, Universal_Integer);
3502 -----------------------
3503 -- Maximum_Alignment --
3504 -----------------------
3506 when Attribute_Maximum_Alignment =>
3507 Standard_Attribute (Ttypes.Maximum_Alignment);
3509 --------------------
3510 -- Mechanism_Code --
3511 --------------------
3513 when Attribute_Mechanism_Code =>
3514 if not Is_Entity_Name (P)
3515 or else not Is_Subprogram (Entity (P))
3517 Error_Attr_P ("prefix of % attribute must be subprogram");
3520 Check_Either_E0_Or_E1;
3522 if Present (E1) then
3523 Resolve (E1, Any_Integer);
3524 Set_Etype (E1, Standard_Integer);
3526 if not Is_Static_Expression (E1) then
3527 Flag_Non_Static_Expr
3528 ("expression for parameter number must be static!", E1);
3531 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3532 or else UI_To_Int (Intval (E1)) < 0
3534 Error_Attr ("invalid parameter number for % attribute", E1);
3538 Set_Etype (N, Universal_Integer);
3544 when Attribute_Min =>
3547 Resolve (E1, P_Base_Type);
3548 Resolve (E2, P_Base_Type);
3549 Set_Etype (N, P_Base_Type);
3555 when Attribute_Mod =>
3557 -- Note: this attribute is only allowed in Ada 2005 mode, but
3558 -- we do not need to test that here, since Mod is only recognized
3559 -- as an attribute name in Ada 2005 mode during the parse.
3562 Check_Modular_Integer_Type;
3563 Resolve (E1, Any_Integer);
3564 Set_Etype (N, P_Base_Type);
3570 when Attribute_Model =>
3571 Check_Floating_Point_Type_1;
3572 Set_Etype (N, P_Base_Type);
3573 Resolve (E1, P_Base_Type);
3579 when Attribute_Model_Emin =>
3580 Check_Floating_Point_Type_0;
3581 Set_Etype (N, Universal_Integer);
3587 when Attribute_Model_Epsilon =>
3588 Check_Floating_Point_Type_0;
3589 Set_Etype (N, Universal_Real);
3591 --------------------
3592 -- Model_Mantissa --
3593 --------------------
3595 when Attribute_Model_Mantissa =>
3596 Check_Floating_Point_Type_0;
3597 Set_Etype (N, Universal_Integer);
3603 when Attribute_Model_Small =>
3604 Check_Floating_Point_Type_0;
3605 Set_Etype (N, Universal_Real);
3611 when Attribute_Modulus =>
3613 Check_Modular_Integer_Type;
3614 Set_Etype (N, Universal_Integer);
3616 --------------------
3617 -- Null_Parameter --
3618 --------------------
3620 when Attribute_Null_Parameter => Null_Parameter : declare
3621 Parnt : constant Node_Id := Parent (N);
3622 GParnt : constant Node_Id := Parent (Parnt);
3624 procedure Bad_Null_Parameter (Msg : String);
3625 -- Used if bad Null parameter attribute node is found. Issues
3626 -- given error message, and also sets the type to Any_Type to
3627 -- avoid blowups later on from dealing with a junk node.
3629 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3630 -- Called to check that Proc_Ent is imported subprogram
3632 ------------------------
3633 -- Bad_Null_Parameter --
3634 ------------------------
3636 procedure Bad_Null_Parameter (Msg : String) is
3638 Error_Msg_N (Msg, N);
3639 Set_Etype (N, Any_Type);
3640 end Bad_Null_Parameter;
3642 ----------------------
3643 -- Must_Be_Imported --
3644 ----------------------
3646 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3647 Pent : constant Entity_Id := Ultimate_Alias (Proc_Ent);
3650 -- Ignore check if procedure not frozen yet (we will get
3651 -- another chance when the default parameter is reanalyzed)
3653 if not Is_Frozen (Pent) then
3656 elsif not Is_Imported (Pent) then
3658 ("Null_Parameter can only be used with imported subprogram");
3663 end Must_Be_Imported;
3665 -- Start of processing for Null_Parameter
3670 Set_Etype (N, P_Type);
3672 -- Case of attribute used as default expression
3674 if Nkind (Parnt) = N_Parameter_Specification then
3675 Must_Be_Imported (Defining_Entity (GParnt));
3677 -- Case of attribute used as actual for subprogram (positional)
3679 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3681 and then Is_Entity_Name (Name (Parnt))
3683 Must_Be_Imported (Entity (Name (Parnt)));
3685 -- Case of attribute used as actual for subprogram (named)
3687 elsif Nkind (Parnt) = N_Parameter_Association
3688 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3690 and then Is_Entity_Name (Name (GParnt))
3692 Must_Be_Imported (Entity (Name (GParnt)));
3694 -- Not an allowed case
3698 ("Null_Parameter must be actual or default parameter");
3706 when Attribute_Object_Size =>
3709 Check_Not_Incomplete_Type;
3710 Set_Etype (N, Universal_Integer);
3716 when Attribute_Old =>
3718 -- The attribute reference is a primary. If expressions follow, the
3719 -- attribute reference is an indexable object, so rewrite the node
3722 if Present (E1) then
3724 Make_Indexed_Component (Loc,
3726 Make_Attribute_Reference (Loc,
3727 Prefix => Relocate_Node (Prefix (N)),
3728 Attribute_Name => Name_Old),
3729 Expressions => Expressions (N)));
3736 Set_Etype (N, P_Type);
3738 if No (Current_Subprogram) then
3739 Error_Attr ("attribute % can only appear within subprogram", N);
3742 if Is_Limited_Type (P_Type) then
3743 Error_Attr ("attribute % cannot apply to limited objects", P);
3746 if Is_Entity_Name (P)
3747 and then Is_Constant_Object (Entity (P))
3750 ("?attribute Old applied to constant has no effect", P);
3753 -- Check that the expression does not refer to local entities
3755 Check_Local : declare
3756 Subp : Entity_Id := Current_Subprogram;
3758 function Process (N : Node_Id) return Traverse_Result;
3759 -- Check that N does not contain references to local variables or
3760 -- other local entities of Subp.
3766 function Process (N : Node_Id) return Traverse_Result is
3768 if Is_Entity_Name (N)
3769 and then Present (Entity (N))
3770 and then not Is_Formal (Entity (N))
3771 and then Enclosing_Subprogram (Entity (N)) = Subp
3773 Error_Msg_Node_1 := Entity (N);
3775 ("attribute % cannot refer to local variable&", N);
3781 procedure Check_No_Local is new Traverse_Proc;
3783 -- Start of processing for Check_Local
3788 if In_Parameter_Specification (P) then
3790 -- We have additional restrictions on using 'Old in parameter
3793 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3795 -- Check that there is no reference to the enclosing
3796 -- subprogram local variables. Otherwise, we might end up
3797 -- being called from the enclosing subprogram and thus using
3798 -- 'Old on a local variable which is not defined at entry
3801 Subp := Enclosing_Subprogram (Current_Subprogram);
3805 -- We must prevent default expression of library-level
3806 -- subprogram from using 'Old, as the subprogram may be
3807 -- used in elaboration code for which there is no enclosing
3811 ("attribute % can only appear within subprogram", N);
3820 when Attribute_Output =>
3822 Check_Stream_Attribute (TSS_Stream_Output);
3823 Set_Etype (N, Standard_Void_Type);
3824 Resolve (N, Standard_Void_Type);
3830 when Attribute_Partition_ID => Partition_Id :
3834 if P_Type /= Any_Type then
3835 if not Is_Library_Level_Entity (Entity (P)) then
3837 ("prefix of % attribute must be library-level entity");
3839 -- The defining entity of prefix should not be declared inside a
3840 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3842 elsif Is_Entity_Name (P)
3843 and then Is_Pure (Entity (P))
3845 Error_Attr_P ("prefix of% attribute must not be declared pure");
3849 Set_Etype (N, Universal_Integer);
3852 -------------------------
3853 -- Passed_By_Reference --
3854 -------------------------
3856 when Attribute_Passed_By_Reference =>
3859 Set_Etype (N, Standard_Boolean);
3865 when Attribute_Pool_Address =>
3867 Set_Etype (N, RTE (RE_Address));
3873 when Attribute_Pos =>
3874 Check_Discrete_Type;
3877 if Is_Boolean_Type (P_Type) then
3878 Error_Msg_Name_1 := Aname;
3879 Error_Msg_Name_2 := Chars (P_Type);
3880 Check_SPARK_Restriction
3881 ("attribute% is not allowed for type%", P);
3884 Resolve (E1, P_Base_Type);
3885 Set_Etype (N, Universal_Integer);
3891 when Attribute_Position =>
3893 Set_Etype (N, Universal_Integer);
3899 when Attribute_Pred =>
3903 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
3904 Error_Msg_Name_1 := Aname;
3905 Error_Msg_Name_2 := Chars (P_Type);
3906 Check_SPARK_Restriction
3907 ("attribute% is not allowed for type%", P);
3910 Resolve (E1, P_Base_Type);
3911 Set_Etype (N, P_Base_Type);
3913 -- Nothing to do for real type case
3915 if Is_Real_Type (P_Type) then
3918 -- If not modular type, test for overflow check required
3921 if not Is_Modular_Integer_Type (P_Type)
3922 and then not Range_Checks_Suppressed (P_Base_Type)
3924 Enable_Range_Check (E1);
3932 -- Ada 2005 (AI-327): Dynamic ceiling priorities
3934 when Attribute_Priority =>
3935 if Ada_Version < Ada_2005 then
3936 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
3941 -- The prefix must be a protected object (AARM D.5.2 (2/2))
3945 if Is_Protected_Type (Etype (P))
3946 or else (Is_Access_Type (Etype (P))
3947 and then Is_Protected_Type (Designated_Type (Etype (P))))
3949 Resolve (P, Etype (P));
3951 Error_Attr_P ("prefix of % attribute must be a protected object");
3954 Set_Etype (N, Standard_Integer);
3956 -- Must be called from within a protected procedure or entry of the
3957 -- protected object.
3964 while S /= Etype (P)
3965 and then S /= Standard_Standard
3970 if S = Standard_Standard then
3971 Error_Attr ("the attribute % is only allowed inside protected "
3976 Validate_Non_Static_Attribute_Function_Call;
3982 when Attribute_Range =>
3983 Check_Array_Or_Scalar_Type;
3984 Bad_Attribute_For_Predicate;
3986 if Ada_Version = Ada_83
3987 and then Is_Scalar_Type (P_Type)
3988 and then Comes_From_Source (N)
3991 ("(Ada 83) % attribute not allowed for scalar type", P);
3998 when Attribute_Result => Result : declare
4000 -- The enclosing scope, excluding loops for quantified expressions
4003 -- During analysis, CS is the postcondition subprogram and PS the
4004 -- source subprogram to which the postcondition applies. During
4005 -- pre-analysis, CS is the scope of the subprogram declaration.
4008 -- Find enclosing scopes, excluding loops
4010 CS := Current_Scope;
4011 while Ekind (CS) = E_Loop loop
4017 -- If the enclosing subprogram is always inlined, the enclosing
4018 -- postcondition will not be propagated to the expanded call.
4020 if not In_Spec_Expression
4021 and then Has_Pragma_Inline_Always (PS)
4022 and then Warn_On_Redundant_Constructs
4025 ("postconditions on inlined functions not enforced?", N);
4028 -- If we are in the scope of a function and in Spec_Expression mode,
4029 -- this is likely the prescan of the postcondition pragma, and we
4030 -- just set the proper type. If there is an error it will be caught
4031 -- when the real Analyze call is done.
4033 if Ekind (CS) = E_Function
4034 and then In_Spec_Expression
4038 if Chars (CS) /= Chars (P) then
4039 Error_Msg_Name_1 := Name_Result;
4042 ("incorrect prefix for % attribute, expected &", P, CS);
4046 -- The attribute reference is a primary. If expressions follow,
4047 -- the attribute reference is really an indexable object, so
4048 -- rewrite and analyze as an indexed component.
4050 if Present (E1) then
4052 Make_Indexed_Component (Loc,
4054 Make_Attribute_Reference (Loc,
4055 Prefix => Relocate_Node (Prefix (N)),
4056 Attribute_Name => Name_Result),
4057 Expressions => Expressions (N)));
4062 Set_Etype (N, Etype (CS));
4064 -- If several functions with that name are visible,
4065 -- the intended one is the current scope.
4067 if Is_Overloaded (P) then
4069 Set_Is_Overloaded (P, False);
4072 -- Body case, where we must be inside a generated _Postcondition
4073 -- procedure, and the prefix must be on the scope stack, or else
4074 -- the attribute use is definitely misplaced. The condition itself
4075 -- may have generated transient scopes, and is not necessarily the
4079 while Present (CS) and then CS /= Standard_Standard loop
4080 if Chars (CS) = Name_uPostconditions then
4089 if Chars (CS) = Name_uPostconditions
4090 and then Ekind (PS) = E_Function
4094 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
4095 and then Chars (P) = Chars (PS)
4099 -- Within an instance, the prefix designates the local renaming
4100 -- of the original generic.
4102 elsif Is_Entity_Name (P)
4103 and then Ekind (Entity (P)) = E_Function
4104 and then Present (Alias (Entity (P)))
4105 and then Chars (Alias (Entity (P))) = Chars (PS)
4111 ("incorrect prefix for % attribute, expected &", P, PS);
4115 Rewrite (N, Make_Identifier (Sloc (N), Name_uResult));
4116 Analyze_And_Resolve (N, Etype (PS));
4120 ("% attribute can only appear" &
4121 " in function Postcondition pragma", P);
4130 when Attribute_Range_Length =>
4132 Check_Discrete_Type;
4133 Set_Etype (N, Universal_Integer);
4139 when Attribute_Read =>
4141 Check_Stream_Attribute (TSS_Stream_Read);
4142 Set_Etype (N, Standard_Void_Type);
4143 Resolve (N, Standard_Void_Type);
4144 Note_Possible_Modification (E2, Sure => True);
4150 when Attribute_Ref =>
4154 if Nkind (P) /= N_Expanded_Name
4155 or else not Is_RTE (P_Type, RE_Address)
4157 Error_Attr_P ("prefix of % attribute must be System.Address");
4160 Analyze_And_Resolve (E1, Any_Integer);
4161 Set_Etype (N, RTE (RE_Address));
4167 when Attribute_Remainder =>
4168 Check_Floating_Point_Type_2;
4169 Set_Etype (N, P_Base_Type);
4170 Resolve (E1, P_Base_Type);
4171 Resolve (E2, P_Base_Type);
4177 when Attribute_Round =>
4179 Check_Decimal_Fixed_Point_Type;
4180 Set_Etype (N, P_Base_Type);
4182 -- Because the context is universal_real (3.5.10(12)) it is a legal
4183 -- context for a universal fixed expression. This is the only
4184 -- attribute whose functional description involves U_R.
4186 if Etype (E1) = Universal_Fixed then
4188 Conv : constant Node_Id := Make_Type_Conversion (Loc,
4189 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
4190 Expression => Relocate_Node (E1));
4198 Resolve (E1, Any_Real);
4204 when Attribute_Rounding =>
4205 Check_Floating_Point_Type_1;
4206 Set_Etype (N, P_Base_Type);
4207 Resolve (E1, P_Base_Type);
4213 when Attribute_Safe_Emax =>
4214 Check_Floating_Point_Type_0;
4215 Set_Etype (N, Universal_Integer);
4221 when Attribute_Safe_First =>
4222 Check_Floating_Point_Type_0;
4223 Set_Etype (N, Universal_Real);
4229 when Attribute_Safe_Large =>
4232 Set_Etype (N, Universal_Real);
4238 when Attribute_Safe_Last =>
4239 Check_Floating_Point_Type_0;
4240 Set_Etype (N, Universal_Real);
4246 when Attribute_Safe_Small =>
4249 Set_Etype (N, Universal_Real);
4255 when Attribute_Scale =>
4257 Check_Decimal_Fixed_Point_Type;
4258 Set_Etype (N, Universal_Integer);
4264 when Attribute_Scaling =>
4265 Check_Floating_Point_Type_2;
4266 Set_Etype (N, P_Base_Type);
4267 Resolve (E1, P_Base_Type);
4273 when Attribute_Signed_Zeros =>
4274 Check_Floating_Point_Type_0;
4275 Set_Etype (N, Standard_Boolean);
4281 when Attribute_Size | Attribute_VADS_Size => Size :
4285 -- If prefix is parameterless function call, rewrite and resolve
4288 if Is_Entity_Name (P)
4289 and then Ekind (Entity (P)) = E_Function
4293 -- Similar processing for a protected function call
4295 elsif Nkind (P) = N_Selected_Component
4296 and then Ekind (Entity (Selector_Name (P))) = E_Function
4301 if Is_Object_Reference (P) then
4302 Check_Object_Reference (P);
4304 elsif Is_Entity_Name (P)
4305 and then (Is_Type (Entity (P))
4306 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4310 elsif Nkind (P) = N_Type_Conversion
4311 and then not Comes_From_Source (P)
4316 Error_Attr_P ("invalid prefix for % attribute");
4319 Check_Not_Incomplete_Type;
4321 Set_Etype (N, Universal_Integer);
4328 when Attribute_Small =>
4331 Set_Etype (N, Universal_Real);
4337 when Attribute_Storage_Pool => Storage_Pool :
4341 if Is_Access_Type (P_Type) then
4342 if Ekind (P_Type) = E_Access_Subprogram_Type then
4344 ("cannot use % attribute for access-to-subprogram type");
4347 -- Set appropriate entity
4349 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4350 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4352 Set_Entity (N, RTE (RE_Global_Pool_Object));
4355 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4357 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4358 -- Storage_Pool since this attribute is not defined for such
4359 -- types (RM E.2.3(22)).
4361 Validate_Remote_Access_To_Class_Wide_Type (N);
4364 Error_Attr_P ("prefix of % attribute must be access type");
4372 when Attribute_Storage_Size => Storage_Size :
4376 if Is_Task_Type (P_Type) then
4377 Set_Etype (N, Universal_Integer);
4379 -- Use with tasks is an obsolescent feature
4381 Check_Restriction (No_Obsolescent_Features, P);
4383 elsif Is_Access_Type (P_Type) then
4384 if Ekind (P_Type) = E_Access_Subprogram_Type then
4386 ("cannot use % attribute for access-to-subprogram type");
4389 if Is_Entity_Name (P)
4390 and then Is_Type (Entity (P))
4393 Set_Etype (N, Universal_Integer);
4395 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4396 -- Storage_Size since this attribute is not defined for
4397 -- such types (RM E.2.3(22)).
4399 Validate_Remote_Access_To_Class_Wide_Type (N);
4401 -- The prefix is allowed to be an implicit dereference
4402 -- of an access value designating a task.
4406 Set_Etype (N, Universal_Integer);
4410 Error_Attr_P ("prefix of % attribute must be access or task type");
4418 when Attribute_Storage_Unit =>
4419 Standard_Attribute (Ttypes.System_Storage_Unit);
4425 when Attribute_Stream_Size =>
4429 if Is_Entity_Name (P)
4430 and then Is_Elementary_Type (Entity (P))
4432 Set_Etype (N, Universal_Integer);
4434 Error_Attr_P ("invalid prefix for % attribute");
4441 when Attribute_Stub_Type =>
4445 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4447 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4450 ("prefix of% attribute must be remote access to classwide");
4457 when Attribute_Succ =>
4461 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
4462 Error_Msg_Name_1 := Aname;
4463 Error_Msg_Name_2 := Chars (P_Type);
4464 Check_SPARK_Restriction
4465 ("attribute% is not allowed for type%", P);
4468 Resolve (E1, P_Base_Type);
4469 Set_Etype (N, P_Base_Type);
4471 -- Nothing to do for real type case
4473 if Is_Real_Type (P_Type) then
4476 -- If not modular type, test for overflow check required
4479 if not Is_Modular_Integer_Type (P_Type)
4480 and then not Range_Checks_Suppressed (P_Base_Type)
4482 Enable_Range_Check (E1);
4490 when Attribute_Tag => Tag :
4495 if not Is_Tagged_Type (P_Type) then
4496 Error_Attr_P ("prefix of % attribute must be tagged");
4498 -- Next test does not apply to generated code
4499 -- why not, and what does the illegal reference mean???
4501 elsif Is_Object_Reference (P)
4502 and then not Is_Class_Wide_Type (P_Type)
4503 and then Comes_From_Source (N)
4506 ("% attribute can only be applied to objects " &
4507 "of class - wide type");
4510 -- The prefix cannot be an incomplete type. However, references
4511 -- to 'Tag can be generated when expanding interface conversions,
4512 -- and this is legal.
4514 if Comes_From_Source (N) then
4515 Check_Not_Incomplete_Type;
4518 -- Set appropriate type
4520 Set_Etype (N, RTE (RE_Tag));
4527 when Attribute_Target_Name => Target_Name : declare
4528 TN : constant String := Sdefault.Target_Name.all;
4532 Check_Standard_Prefix;
4536 if TN (TL) = '/' or else TN (TL) = '\' then
4541 Make_String_Literal (Loc,
4542 Strval => TN (TN'First .. TL)));
4543 Analyze_And_Resolve (N, Standard_String);
4550 when Attribute_Terminated =>
4552 Set_Etype (N, Standard_Boolean);
4559 when Attribute_To_Address =>
4563 if Nkind (P) /= N_Identifier
4564 or else Chars (P) /= Name_System
4566 Error_Attr_P ("prefix of % attribute must be System");
4569 Generate_Reference (RTE (RE_Address), P);
4570 Analyze_And_Resolve (E1, Any_Integer);
4571 Set_Etype (N, RTE (RE_Address));
4577 when Attribute_To_Any =>
4579 Check_PolyORB_Attribute;
4580 Set_Etype (N, RTE (RE_Any));
4586 when Attribute_Truncation =>
4587 Check_Floating_Point_Type_1;
4588 Resolve (E1, P_Base_Type);
4589 Set_Etype (N, P_Base_Type);
4595 when Attribute_Type_Class =>
4598 Check_Not_Incomplete_Type;
4599 Set_Etype (N, RTE (RE_Type_Class));
4605 when Attribute_TypeCode =>
4607 Check_PolyORB_Attribute;
4608 Set_Etype (N, RTE (RE_TypeCode));
4614 when Attribute_Type_Key =>
4618 -- This processing belongs in Eval_Attribute ???
4621 function Type_Key return String_Id;
4622 -- A very preliminary implementation. For now, a signature
4623 -- consists of only the type name. This is clearly incomplete
4624 -- (e.g., adding a new field to a record type should change the
4625 -- type's Type_Key attribute).
4631 function Type_Key return String_Id is
4632 Full_Name : constant String_Id :=
4633 Fully_Qualified_Name_String (Entity (P));
4636 -- Copy all characters in Full_Name but the trailing NUL
4639 for J in 1 .. String_Length (Full_Name) - 1 loop
4640 Store_String_Char (Get_String_Char (Full_Name, Int (J)));
4643 Store_String_Chars ("'Type_Key");
4648 Rewrite (N, Make_String_Literal (Loc, Type_Key));
4651 Analyze_And_Resolve (N, Standard_String);
4657 when Attribute_UET_Address =>
4659 Check_Unit_Name (P);
4660 Set_Etype (N, RTE (RE_Address));
4662 -----------------------
4663 -- Unbiased_Rounding --
4664 -----------------------
4666 when Attribute_Unbiased_Rounding =>
4667 Check_Floating_Point_Type_1;
4668 Set_Etype (N, P_Base_Type);
4669 Resolve (E1, P_Base_Type);
4671 ----------------------
4672 -- Unchecked_Access --
4673 ----------------------
4675 when Attribute_Unchecked_Access =>
4676 if Comes_From_Source (N) then
4677 Check_Restriction (No_Unchecked_Access, N);
4680 Analyze_Access_Attribute;
4682 -------------------------
4683 -- Unconstrained_Array --
4684 -------------------------
4686 when Attribute_Unconstrained_Array =>
4689 Check_Not_Incomplete_Type;
4690 Set_Etype (N, Standard_Boolean);
4692 ------------------------------
4693 -- Universal_Literal_String --
4694 ------------------------------
4696 -- This is a GNAT specific attribute whose prefix must be a named
4697 -- number where the expression is either a single numeric literal,
4698 -- or a numeric literal immediately preceded by a minus sign. The
4699 -- result is equivalent to a string literal containing the text of
4700 -- the literal as it appeared in the source program with a possible
4701 -- leading minus sign.
4703 when Attribute_Universal_Literal_String => Universal_Literal_String :
4707 if not Is_Entity_Name (P)
4708 or else Ekind (Entity (P)) not in Named_Kind
4710 Error_Attr_P ("prefix for % attribute must be named number");
4717 Src : Source_Buffer_Ptr;
4720 Expr := Original_Node (Expression (Parent (Entity (P))));
4722 if Nkind (Expr) = N_Op_Minus then
4724 Expr := Original_Node (Right_Opnd (Expr));
4729 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4731 ("named number for % attribute must be simple literal", N);
4734 -- Build string literal corresponding to source literal text
4739 Store_String_Char (Get_Char_Code ('-'));
4743 Src := Source_Text (Get_Source_File_Index (S));
4745 while Src (S) /= ';' and then Src (S) /= ' ' loop
4746 Store_String_Char (Get_Char_Code (Src (S)));
4750 -- Now we rewrite the attribute with the string literal
4753 Make_String_Literal (Loc, End_String));
4757 end Universal_Literal_String;
4759 -------------------------
4760 -- Unrestricted_Access --
4761 -------------------------
4763 -- This is a GNAT specific attribute which is like Access except that
4764 -- all scope checks and checks for aliased views are omitted.
4766 when Attribute_Unrestricted_Access =>
4767 if Comes_From_Source (N) then
4768 Check_Restriction (No_Unchecked_Access, N);
4771 if Is_Entity_Name (P) then
4772 Set_Address_Taken (Entity (P));
4775 Analyze_Access_Attribute;
4781 when Attribute_Val => Val : declare
4784 Check_Discrete_Type;
4786 if Is_Boolean_Type (P_Type) then
4787 Error_Msg_Name_1 := Aname;
4788 Error_Msg_Name_2 := Chars (P_Type);
4789 Check_SPARK_Restriction
4790 ("attribute% is not allowed for type%", P);
4793 Resolve (E1, Any_Integer);
4794 Set_Etype (N, P_Base_Type);
4796 -- Note, we need a range check in general, but we wait for the
4797 -- Resolve call to do this, since we want to let Eval_Attribute
4798 -- have a chance to find an static illegality first!
4805 when Attribute_Valid =>
4808 -- Ignore check for object if we have a 'Valid reference generated
4809 -- by the expanded code, since in some cases valid checks can occur
4810 -- on items that are names, but are not objects (e.g. attributes).
4812 if Comes_From_Source (N) then
4813 Check_Object_Reference (P);
4816 if not Is_Scalar_Type (P_Type) then
4817 Error_Attr_P ("object for % attribute must be of scalar type");
4820 Set_Etype (N, Standard_Boolean);
4826 when Attribute_Value => Value :
4828 Check_Formal_Restriction_On_Attribute;
4832 -- Case of enumeration type
4834 if Is_Enumeration_Type (P_Type) then
4835 Check_Restriction (No_Enumeration_Maps, N);
4837 -- Mark all enumeration literals as referenced, since the use of
4838 -- the Value attribute can implicitly reference any of the
4839 -- literals of the enumeration base type.
4842 Ent : Entity_Id := First_Literal (P_Base_Type);
4844 while Present (Ent) loop
4845 Set_Referenced (Ent);
4851 -- Set Etype before resolving expression because expansion of
4852 -- expression may require enclosing type. Note that the type
4853 -- returned by 'Value is the base type of the prefix type.
4855 Set_Etype (N, P_Base_Type);
4856 Validate_Non_Static_Attribute_Function_Call;
4863 when Attribute_Value_Size =>
4866 Check_Not_Incomplete_Type;
4867 Set_Etype (N, Universal_Integer);
4873 when Attribute_Version =>
4876 Set_Etype (N, RTE (RE_Version_String));
4882 when Attribute_Wchar_T_Size =>
4883 Standard_Attribute (Interfaces_Wchar_T_Size);
4889 when Attribute_Wide_Image => Wide_Image :
4891 Check_Formal_Restriction_On_Attribute;
4893 Set_Etype (N, Standard_Wide_String);
4895 Resolve (E1, P_Base_Type);
4896 Validate_Non_Static_Attribute_Function_Call;
4899 ---------------------
4900 -- Wide_Wide_Image --
4901 ---------------------
4903 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
4906 Set_Etype (N, Standard_Wide_Wide_String);
4908 Resolve (E1, P_Base_Type);
4909 Validate_Non_Static_Attribute_Function_Call;
4910 end Wide_Wide_Image;
4916 when Attribute_Wide_Value => Wide_Value :
4918 Check_Formal_Restriction_On_Attribute;
4922 -- Set Etype before resolving expression because expansion
4923 -- of expression may require enclosing type.
4925 Set_Etype (N, P_Type);
4926 Validate_Non_Static_Attribute_Function_Call;
4929 ---------------------
4930 -- Wide_Wide_Value --
4931 ---------------------
4933 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
4938 -- Set Etype before resolving expression because expansion
4939 -- of expression may require enclosing type.
4941 Set_Etype (N, P_Type);
4942 Validate_Non_Static_Attribute_Function_Call;
4943 end Wide_Wide_Value;
4945 ---------------------
4946 -- Wide_Wide_Width --
4947 ---------------------
4949 when Attribute_Wide_Wide_Width =>
4952 Set_Etype (N, Universal_Integer);
4958 when Attribute_Wide_Width =>
4959 Check_Formal_Restriction_On_Attribute;
4962 Set_Etype (N, Universal_Integer);
4968 when Attribute_Width =>
4969 Check_Formal_Restriction_On_Attribute;
4972 Set_Etype (N, Universal_Integer);
4978 when Attribute_Word_Size =>
4979 Standard_Attribute (System_Word_Size);
4985 when Attribute_Write =>
4987 Check_Stream_Attribute (TSS_Stream_Write);
4988 Set_Etype (N, Standard_Void_Type);
4989 Resolve (N, Standard_Void_Type);
4993 -- All errors raise Bad_Attribute, so that we get out before any further
4994 -- damage occurs when an error is detected (for example, if we check for
4995 -- one attribute expression, and the check succeeds, we want to be able
4996 -- to proceed securely assuming that an expression is in fact present.
4998 -- Note: we set the attribute analyzed in this case to prevent any
4999 -- attempt at reanalysis which could generate spurious error msgs.
5002 when Bad_Attribute =>
5004 Set_Etype (N, Any_Type);
5006 end Analyze_Attribute;
5008 --------------------
5009 -- Eval_Attribute --
5010 --------------------
5012 procedure Eval_Attribute (N : Node_Id) is
5013 Loc : constant Source_Ptr := Sloc (N);
5014 Aname : constant Name_Id := Attribute_Name (N);
5015 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
5016 P : constant Node_Id := Prefix (N);
5018 C_Type : constant Entity_Id := Etype (N);
5019 -- The type imposed by the context
5022 -- First expression, or Empty if none
5025 -- Second expression, or Empty if none
5027 P_Entity : Entity_Id;
5028 -- Entity denoted by prefix
5031 -- The type of the prefix
5033 P_Base_Type : Entity_Id;
5034 -- The base type of the prefix type
5036 P_Root_Type : Entity_Id;
5037 -- The root type of the prefix type
5040 -- True if the result is Static. This is set by the general processing
5041 -- to true if the prefix is static, and all expressions are static. It
5042 -- can be reset as processing continues for particular attributes
5044 Lo_Bound, Hi_Bound : Node_Id;
5045 -- Expressions for low and high bounds of type or array index referenced
5046 -- by First, Last, or Length attribute for array, set by Set_Bounds.
5049 -- Constraint error node used if we have an attribute reference has
5050 -- an argument that raises a constraint error. In this case we replace
5051 -- the attribute with a raise constraint_error node. This is important
5052 -- processing, since otherwise gigi might see an attribute which it is
5053 -- unprepared to deal with.
5055 procedure Check_Concurrent_Discriminant (Bound : Node_Id);
5056 -- If Bound is a reference to a discriminant of a task or protected type
5057 -- occurring within the object's body, rewrite attribute reference into
5058 -- a reference to the corresponding discriminal. Use for the expansion
5059 -- of checks against bounds of entry family index subtypes.
5061 procedure Check_Expressions;
5062 -- In case where the attribute is not foldable, the expressions, if
5063 -- any, of the attribute, are in a non-static context. This procedure
5064 -- performs the required additional checks.
5066 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
5067 -- Determines if the given type has compile time known bounds. Note
5068 -- that we enter the case statement even in cases where the prefix
5069 -- type does NOT have known bounds, so it is important to guard any
5070 -- attempt to evaluate both bounds with a call to this function.
5072 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
5073 -- This procedure is called when the attribute N has a non-static
5074 -- but compile time known value given by Val. It includes the
5075 -- necessary checks for out of range values.
5077 function Fore_Value return Nat;
5078 -- Computes the Fore value for the current attribute prefix, which is
5079 -- known to be a static fixed-point type. Used by Fore and Width.
5081 function Mantissa return Uint;
5082 -- Returns the Mantissa value for the prefix type
5084 procedure Set_Bounds;
5085 -- Used for First, Last and Length attributes applied to an array or
5086 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
5087 -- and high bound expressions for the index referenced by the attribute
5088 -- designator (i.e. the first index if no expression is present, and
5089 -- the N'th index if the value N is present as an expression). Also
5090 -- used for First and Last of scalar types. Static is reset to False
5091 -- if the type or index type is not statically constrained.
5093 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
5094 -- Verify that the prefix of a potentially static array attribute
5095 -- satisfies the conditions of 4.9 (14).
5097 -----------------------------------
5098 -- Check_Concurrent_Discriminant --
5099 -----------------------------------
5101 procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
5103 -- The concurrent (task or protected) type
5106 if Nkind (Bound) = N_Identifier
5107 and then Ekind (Entity (Bound)) = E_Discriminant
5108 and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
5110 Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
5112 if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
5114 -- Find discriminant of original concurrent type, and use
5115 -- its current discriminal, which is the renaming within
5116 -- the task/protected body.
5120 (Find_Body_Discriminal (Entity (Bound)), Loc));
5123 end Check_Concurrent_Discriminant;
5125 -----------------------
5126 -- Check_Expressions --
5127 -----------------------
5129 procedure Check_Expressions is
5133 while Present (E) loop
5134 Check_Non_Static_Context (E);
5137 end Check_Expressions;
5139 ----------------------------------
5140 -- Compile_Time_Known_Attribute --
5141 ----------------------------------
5143 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
5144 T : constant Entity_Id := Etype (N);
5147 Fold_Uint (N, Val, False);
5149 -- Check that result is in bounds of the type if it is static
5151 if Is_In_Range (N, T, Assume_Valid => False) then
5154 elsif Is_Out_Of_Range (N, T) then
5155 Apply_Compile_Time_Constraint_Error
5156 (N, "value not in range of}?", CE_Range_Check_Failed);
5158 elsif not Range_Checks_Suppressed (T) then
5159 Enable_Range_Check (N);
5162 Set_Do_Range_Check (N, False);
5164 end Compile_Time_Known_Attribute;
5166 -------------------------------
5167 -- Compile_Time_Known_Bounds --
5168 -------------------------------
5170 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
5173 Compile_Time_Known_Value (Type_Low_Bound (Typ))
5175 Compile_Time_Known_Value (Type_High_Bound (Typ));
5176 end Compile_Time_Known_Bounds;
5182 -- Note that the Fore calculation is based on the actual values
5183 -- of the bounds, and does not take into account possible rounding.
5185 function Fore_Value return Nat is
5186 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
5187 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
5188 Small : constant Ureal := Small_Value (P_Type);
5189 Lo_Real : constant Ureal := Lo * Small;
5190 Hi_Real : constant Ureal := Hi * Small;
5195 -- Bounds are given in terms of small units, so first compute
5196 -- proper values as reals.
5198 T := UR_Max (abs Lo_Real, abs Hi_Real);
5201 -- Loop to compute proper value if more than one digit required
5203 while T >= Ureal_10 loop
5215 -- Table of mantissa values accessed by function Computed using
5218 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5220 -- where D is T'Digits (RM83 3.5.7)
5222 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5264 function Mantissa return Uint is
5267 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5274 procedure Set_Bounds is
5280 -- For a string literal subtype, we have to construct the bounds.
5281 -- Valid Ada code never applies attributes to string literals, but
5282 -- it is convenient to allow the expander to generate attribute
5283 -- references of this type (e.g. First and Last applied to a string
5286 -- Note that the whole point of the E_String_Literal_Subtype is to
5287 -- avoid this construction of bounds, but the cases in which we
5288 -- have to materialize them are rare enough that we don't worry!
5290 -- The low bound is simply the low bound of the base type. The
5291 -- high bound is computed from the length of the string and this
5294 if Ekind (P_Type) = E_String_Literal_Subtype then
5295 Ityp := Etype (First_Index (Base_Type (P_Type)));
5296 Lo_Bound := Type_Low_Bound (Ityp);
5299 Make_Integer_Literal (Sloc (P),
5301 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5303 Set_Parent (Hi_Bound, P);
5304 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5307 -- For non-array case, just get bounds of scalar type
5309 elsif Is_Scalar_Type (P_Type) then
5312 -- For a fixed-point type, we must freeze to get the attributes
5313 -- of the fixed-point type set now so we can reference them.
5315 if Is_Fixed_Point_Type (P_Type)
5316 and then not Is_Frozen (Base_Type (P_Type))
5317 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5318 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5320 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5323 -- For array case, get type of proper index
5329 Ndim := UI_To_Int (Expr_Value (E1));
5332 Indx := First_Index (P_Type);
5333 for J in 1 .. Ndim - 1 loop
5337 -- If no index type, get out (some other error occurred, and
5338 -- we don't have enough information to complete the job!)
5346 Ityp := Etype (Indx);
5349 -- A discrete range in an index constraint is allowed to be a
5350 -- subtype indication. This is syntactically a pain, but should
5351 -- not propagate to the entity for the corresponding index subtype.
5352 -- After checking that the subtype indication is legal, the range
5353 -- of the subtype indication should be transfered to the entity.
5354 -- The attributes for the bounds should remain the simple retrievals
5355 -- that they are now.
5357 Lo_Bound := Type_Low_Bound (Ityp);
5358 Hi_Bound := Type_High_Bound (Ityp);
5360 if not Is_Static_Subtype (Ityp) then
5365 -------------------------------
5366 -- Statically_Denotes_Entity --
5367 -------------------------------
5369 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5373 if not Is_Entity_Name (N) then
5380 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5381 or else Statically_Denotes_Entity (Renamed_Object (E));
5382 end Statically_Denotes_Entity;
5384 -- Start of processing for Eval_Attribute
5387 -- No folding in spec expression that comes from source where the prefix
5388 -- is an unfrozen entity. This avoids premature folding in cases like:
5390 -- procedure DefExprAnal is
5391 -- type R is new Integer;
5392 -- procedure P (Arg : Integer := R'Size);
5393 -- for R'Size use 64;
5394 -- procedure P (Arg : Integer := R'Size) is
5396 -- Put_Line (Arg'Img);
5402 -- which should print 64 rather than 32. The exclusion of non-source
5403 -- constructs from this test comes from some internal usage in packed
5404 -- arrays, which otherwise fails, could use more analysis perhaps???
5406 -- We do however go ahead with generic actual types, otherwise we get
5407 -- some regressions, probably these types should be frozen anyway???
5409 if In_Spec_Expression
5410 and then Comes_From_Source (N)
5411 and then not (Is_Entity_Name (P)
5413 (Is_Frozen (Entity (P))
5414 or else (Is_Type (Entity (P))
5416 Is_Generic_Actual_Type (Entity (P)))))
5421 -- Acquire first two expressions (at the moment, no attributes take more
5422 -- than two expressions in any case).
5424 if Present (Expressions (N)) then
5425 E1 := First (Expressions (N));
5432 -- Special processing for Enabled attribute. This attribute has a very
5433 -- special prefix, and the easiest way to avoid lots of special checks
5434 -- to protect this special prefix from causing trouble is to deal with
5435 -- this attribute immediately and be done with it.
5437 if Id = Attribute_Enabled then
5439 -- We skip evaluation if the expander is not active. This is not just
5440 -- an optimization. It is of key importance that we not rewrite the
5441 -- attribute in a generic template, since we want to pick up the
5442 -- setting of the check in the instance, and testing expander active
5443 -- is as easy way of doing this as any.
5445 if Expander_Active then
5447 C : constant Check_Id := Get_Check_Id (Chars (P));
5452 if C in Predefined_Check_Id then
5453 R := Scope_Suppress (C);
5455 R := Is_Check_Suppressed (Empty, C);
5459 R := Is_Check_Suppressed (Entity (E1), C);
5463 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5465 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5473 -- Special processing for cases where the prefix is an object. For
5474 -- this purpose, a string literal counts as an object (attributes
5475 -- of string literals can only appear in generated code).
5477 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5479 -- For Component_Size, the prefix is an array object, and we apply
5480 -- the attribute to the type of the object. This is allowed for
5481 -- both unconstrained and constrained arrays, since the bounds
5482 -- have no influence on the value of this attribute.
5484 if Id = Attribute_Component_Size then
5485 P_Entity := Etype (P);
5487 -- For First and Last, the prefix is an array object, and we apply
5488 -- the attribute to the type of the array, but we need a constrained
5489 -- type for this, so we use the actual subtype if available.
5491 elsif Id = Attribute_First
5495 Id = Attribute_Length
5498 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5501 if Present (AS) and then Is_Constrained (AS) then
5504 -- If we have an unconstrained type we cannot fold
5512 -- For Size, give size of object if available, otherwise we
5513 -- cannot fold Size.
5515 elsif Id = Attribute_Size then
5516 if Is_Entity_Name (P)
5517 and then Known_Esize (Entity (P))
5519 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5527 -- For Alignment, give size of object if available, otherwise we
5528 -- cannot fold Alignment.
5530 elsif Id = Attribute_Alignment then
5531 if Is_Entity_Name (P)
5532 and then Known_Alignment (Entity (P))
5534 Fold_Uint (N, Alignment (Entity (P)), False);
5542 -- No other attributes for objects are folded
5549 -- Cases where P is not an object. Cannot do anything if P is
5550 -- not the name of an entity.
5552 elsif not Is_Entity_Name (P) then
5556 -- Otherwise get prefix entity
5559 P_Entity := Entity (P);
5562 -- At this stage P_Entity is the entity to which the attribute
5563 -- is to be applied. This is usually simply the entity of the
5564 -- prefix, except in some cases of attributes for objects, where
5565 -- as described above, we apply the attribute to the object type.
5567 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5568 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5569 -- Note we allow non-static non-generic types at this stage as further
5572 if Is_Type (P_Entity)
5573 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5574 and then (not Is_Generic_Type (P_Entity))
5578 -- Second foldable possibility is an array object (RM 4.9(8))
5580 elsif (Ekind (P_Entity) = E_Variable
5582 Ekind (P_Entity) = E_Constant)
5583 and then Is_Array_Type (Etype (P_Entity))
5584 and then (not Is_Generic_Type (Etype (P_Entity)))
5586 P_Type := Etype (P_Entity);
5588 -- If the entity is an array constant with an unconstrained nominal
5589 -- subtype then get the type from the initial value. If the value has
5590 -- been expanded into assignments, there is no expression and the
5591 -- attribute reference remains dynamic.
5593 -- We could do better here and retrieve the type ???
5595 if Ekind (P_Entity) = E_Constant
5596 and then not Is_Constrained (P_Type)
5598 if No (Constant_Value (P_Entity)) then
5601 P_Type := Etype (Constant_Value (P_Entity));
5605 -- Definite must be folded if the prefix is not a generic type,
5606 -- that is to say if we are within an instantiation. Same processing
5607 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5608 -- Has_Tagged_Value, and Unconstrained_Array.
5610 elsif (Id = Attribute_Definite
5612 Id = Attribute_Has_Access_Values
5614 Id = Attribute_Has_Discriminants
5616 Id = Attribute_Has_Tagged_Values
5618 Id = Attribute_Type_Class
5620 Id = Attribute_Unconstrained_Array
5622 Id = Attribute_Max_Alignment_For_Allocation)
5623 and then not Is_Generic_Type (P_Entity)
5627 -- We can fold 'Size applied to a type if the size is known (as happens
5628 -- for a size from an attribute definition clause). At this stage, this
5629 -- can happen only for types (e.g. record types) for which the size is
5630 -- always non-static. We exclude generic types from consideration (since
5631 -- they have bogus sizes set within templates).
5633 elsif Id = Attribute_Size
5634 and then Is_Type (P_Entity)
5635 and then (not Is_Generic_Type (P_Entity))
5636 and then Known_Static_RM_Size (P_Entity)
5638 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5641 -- We can fold 'Alignment applied to a type if the alignment is known
5642 -- (as happens for an alignment from an attribute definition clause).
5643 -- At this stage, this can happen only for types (e.g. record
5644 -- types) for which the size is always non-static. We exclude
5645 -- generic types from consideration (since they have bogus
5646 -- sizes set within templates).
5648 elsif Id = Attribute_Alignment
5649 and then Is_Type (P_Entity)
5650 and then (not Is_Generic_Type (P_Entity))
5651 and then Known_Alignment (P_Entity)
5653 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5656 -- If this is an access attribute that is known to fail accessibility
5657 -- check, rewrite accordingly.
5659 elsif Attribute_Name (N) = Name_Access
5660 and then Raises_Constraint_Error (N)
5663 Make_Raise_Program_Error (Loc,
5664 Reason => PE_Accessibility_Check_Failed));
5665 Set_Etype (N, C_Type);
5668 -- No other cases are foldable (they certainly aren't static, and at
5669 -- the moment we don't try to fold any cases other than these three).
5676 -- If either attribute or the prefix is Any_Type, then propagate
5677 -- Any_Type to the result and don't do anything else at all.
5679 if P_Type = Any_Type
5680 or else (Present (E1) and then Etype (E1) = Any_Type)
5681 or else (Present (E2) and then Etype (E2) = Any_Type)
5683 Set_Etype (N, Any_Type);
5687 -- Scalar subtype case. We have not yet enforced the static requirement
5688 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5689 -- of non-static attribute references (e.g. S'Digits for a non-static
5690 -- floating-point type, which we can compute at compile time).
5692 -- Note: this folding of non-static attributes is not simply a case of
5693 -- optimization. For many of the attributes affected, Gigi cannot handle
5694 -- the attribute and depends on the front end having folded them away.
5696 -- Note: although we don't require staticness at this stage, we do set
5697 -- the Static variable to record the staticness, for easy reference by
5698 -- those attributes where it matters (e.g. Succ and Pred), and also to
5699 -- be used to ensure that non-static folded things are not marked as
5700 -- being static (a check that is done right at the end).
5702 P_Root_Type := Root_Type (P_Type);
5703 P_Base_Type := Base_Type (P_Type);
5705 -- If the root type or base type is generic, then we cannot fold. This
5706 -- test is needed because subtypes of generic types are not always
5707 -- marked as being generic themselves (which seems odd???)
5709 if Is_Generic_Type (P_Root_Type)
5710 or else Is_Generic_Type (P_Base_Type)
5715 if Is_Scalar_Type (P_Type) then
5716 Static := Is_OK_Static_Subtype (P_Type);
5718 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5719 -- since we can't do anything with unconstrained arrays. In addition,
5720 -- only the First, Last and Length attributes are possibly static.
5722 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5723 -- Type_Class, and Unconstrained_Array are again exceptions, because
5724 -- they apply as well to unconstrained types.
5726 -- In addition Component_Size is an exception since it is possibly
5727 -- foldable, even though it is never static, and it does apply to
5728 -- unconstrained arrays. Furthermore, it is essential to fold this
5729 -- in the packed case, since otherwise the value will be incorrect.
5731 elsif Id = Attribute_Definite
5733 Id = Attribute_Has_Access_Values
5735 Id = Attribute_Has_Discriminants
5737 Id = Attribute_Has_Tagged_Values
5739 Id = Attribute_Type_Class
5741 Id = Attribute_Unconstrained_Array
5743 Id = Attribute_Component_Size
5747 elsif Id /= Attribute_Max_Alignment_For_Allocation then
5748 if not Is_Constrained (P_Type)
5749 or else (Id /= Attribute_First and then
5750 Id /= Attribute_Last and then
5751 Id /= Attribute_Length)
5757 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5758 -- scalar case, we hold off on enforcing staticness, since there are
5759 -- cases which we can fold at compile time even though they are not
5760 -- static (e.g. 'Length applied to a static index, even though other
5761 -- non-static indexes make the array type non-static). This is only
5762 -- an optimization, but it falls out essentially free, so why not.
5763 -- Again we compute the variable Static for easy reference later
5764 -- (note that no array attributes are static in Ada 83).
5766 -- We also need to set Static properly for subsequent legality checks
5767 -- which might otherwise accept non-static constants in contexts
5768 -- where they are not legal.
5770 Static := Ada_Version >= Ada_95
5771 and then Statically_Denotes_Entity (P);
5777 N := First_Index (P_Type);
5779 -- The expression is static if the array type is constrained
5780 -- by given bounds, and not by an initial expression. Constant
5781 -- strings are static in any case.
5783 if Root_Type (P_Type) /= Standard_String then
5785 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
5788 while Present (N) loop
5789 Static := Static and then Is_Static_Subtype (Etype (N));
5791 -- If however the index type is generic, or derived from
5792 -- one, attributes cannot be folded.
5794 if Is_Generic_Type (Root_Type (Etype (N)))
5795 and then Id /= Attribute_Component_Size
5805 -- Check any expressions that are present. Note that these expressions,
5806 -- depending on the particular attribute type, are either part of the
5807 -- attribute designator, or they are arguments in a case where the
5808 -- attribute reference returns a function. In the latter case, the
5809 -- rule in (RM 4.9(22)) applies and in particular requires the type
5810 -- of the expressions to be scalar in order for the attribute to be
5811 -- considered to be static.
5818 while Present (E) loop
5820 -- If expression is not static, then the attribute reference
5821 -- result certainly cannot be static.
5823 if not Is_Static_Expression (E) then
5827 -- If the result is not known at compile time, or is not of
5828 -- a scalar type, then the result is definitely not static,
5829 -- so we can quit now.
5831 if not Compile_Time_Known_Value (E)
5832 or else not Is_Scalar_Type (Etype (E))
5834 -- An odd special case, if this is a Pos attribute, this
5835 -- is where we need to apply a range check since it does
5836 -- not get done anywhere else.
5838 if Id = Attribute_Pos then
5839 if Is_Integer_Type (Etype (E)) then
5840 Apply_Range_Check (E, Etype (N));
5847 -- If the expression raises a constraint error, then so does
5848 -- the attribute reference. We keep going in this case because
5849 -- we are still interested in whether the attribute reference
5850 -- is static even if it is not static.
5852 elsif Raises_Constraint_Error (E) then
5853 Set_Raises_Constraint_Error (N);
5859 if Raises_Constraint_Error (Prefix (N)) then
5864 -- Deal with the case of a static attribute reference that raises
5865 -- constraint error. The Raises_Constraint_Error flag will already
5866 -- have been set, and the Static flag shows whether the attribute
5867 -- reference is static. In any case we certainly can't fold such an
5868 -- attribute reference.
5870 -- Note that the rewriting of the attribute node with the constraint
5871 -- error node is essential in this case, because otherwise Gigi might
5872 -- blow up on one of the attributes it never expects to see.
5874 -- The constraint_error node must have the type imposed by the context,
5875 -- to avoid spurious errors in the enclosing expression.
5877 if Raises_Constraint_Error (N) then
5879 Make_Raise_Constraint_Error (Sloc (N),
5880 Reason => CE_Range_Check_Failed);
5881 Set_Etype (CE_Node, Etype (N));
5882 Set_Raises_Constraint_Error (CE_Node);
5884 Rewrite (N, Relocate_Node (CE_Node));
5885 Set_Is_Static_Expression (N, Static);
5889 -- At this point we have a potentially foldable attribute reference.
5890 -- If Static is set, then the attribute reference definitely obeys
5891 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
5892 -- folded. If Static is not set, then the attribute may or may not
5893 -- be foldable, and the individual attribute processing routines
5894 -- test Static as required in cases where it makes a difference.
5896 -- In the case where Static is not set, we do know that all the
5897 -- expressions present are at least known at compile time (we
5898 -- assumed above that if this was not the case, then there was
5899 -- no hope of static evaluation). However, we did not require
5900 -- that the bounds of the prefix type be compile time known,
5901 -- let alone static). That's because there are many attributes
5902 -- that can be computed at compile time on non-static subtypes,
5903 -- even though such references are not static expressions.
5911 when Attribute_Adjacent =>
5914 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5920 when Attribute_Aft =>
5921 Fold_Uint (N, Aft_Value (P_Type), True);
5927 when Attribute_Alignment => Alignment_Block : declare
5928 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5931 -- Fold if alignment is set and not otherwise
5933 if Known_Alignment (P_TypeA) then
5934 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
5936 end Alignment_Block;
5942 -- Can only be folded in No_Ast_Handler case
5944 when Attribute_AST_Entry =>
5945 if not Is_AST_Entry (P_Entity) then
5947 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
5956 -- Bit can never be folded
5958 when Attribute_Bit =>
5965 -- Body_version can never be static
5967 when Attribute_Body_Version =>
5974 when Attribute_Ceiling =>
5976 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
5978 --------------------
5979 -- Component_Size --
5980 --------------------
5982 when Attribute_Component_Size =>
5983 if Known_Static_Component_Size (P_Type) then
5984 Fold_Uint (N, Component_Size (P_Type), False);
5991 when Attribute_Compose =>
5994 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
6001 -- Constrained is never folded for now, there may be cases that
6002 -- could be handled at compile time. To be looked at later.
6004 when Attribute_Constrained =>
6011 when Attribute_Copy_Sign =>
6014 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6020 when Attribute_Definite =>
6021 Rewrite (N, New_Occurrence_Of (
6022 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
6023 Analyze_And_Resolve (N, Standard_Boolean);
6029 when Attribute_Delta =>
6030 Fold_Ureal (N, Delta_Value (P_Type), True);
6036 when Attribute_Denorm =>
6038 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
6044 when Attribute_Digits =>
6045 Fold_Uint (N, Digits_Value (P_Type), True);
6051 when Attribute_Emax =>
6053 -- Ada 83 attribute is defined as (RM83 3.5.8)
6055 -- T'Emax = 4 * T'Mantissa
6057 Fold_Uint (N, 4 * Mantissa, True);
6063 when Attribute_Enum_Rep =>
6065 -- For an enumeration type with a non-standard representation use
6066 -- the Enumeration_Rep field of the proper constant. Note that this
6067 -- will not work for types Character/Wide_[Wide-]Character, since no
6068 -- real entities are created for the enumeration literals, but that
6069 -- does not matter since these two types do not have non-standard
6070 -- representations anyway.
6072 if Is_Enumeration_Type (P_Type)
6073 and then Has_Non_Standard_Rep (P_Type)
6075 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
6077 -- For enumeration types with standard representations and all
6078 -- other cases (i.e. all integer and modular types), Enum_Rep
6079 -- is equivalent to Pos.
6082 Fold_Uint (N, Expr_Value (E1), Static);
6089 when Attribute_Enum_Val => Enum_Val : declare
6093 -- We have something like Enum_Type'Enum_Val (23), so search for a
6094 -- corresponding value in the list of Enum_Rep values for the type.
6096 Lit := First_Literal (P_Base_Type);
6098 if Enumeration_Rep (Lit) = Expr_Value (E1) then
6099 Fold_Uint (N, Enumeration_Pos (Lit), Static);
6106 Apply_Compile_Time_Constraint_Error
6107 (N, "no representation value matches",
6108 CE_Range_Check_Failed,
6109 Warn => not Static);
6119 when Attribute_Epsilon =>
6121 -- Ada 83 attribute is defined as (RM83 3.5.8)
6123 -- T'Epsilon = 2.0**(1 - T'Mantissa)
6125 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
6131 when Attribute_Exponent =>
6133 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
6139 when Attribute_First => First_Attr :
6143 if Compile_Time_Known_Value (Lo_Bound) then
6144 if Is_Real_Type (P_Type) then
6145 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
6147 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
6151 Check_Concurrent_Discriminant (Lo_Bound);
6159 when Attribute_Fixed_Value =>
6166 when Attribute_Floor =>
6168 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
6174 when Attribute_Fore =>
6175 if Compile_Time_Known_Bounds (P_Type) then
6176 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
6183 when Attribute_Fraction =>
6185 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
6187 -----------------------
6188 -- Has_Access_Values --
6189 -----------------------
6191 when Attribute_Has_Access_Values =>
6192 Rewrite (N, New_Occurrence_Of
6193 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
6194 Analyze_And_Resolve (N, Standard_Boolean);
6196 -----------------------
6197 -- Has_Discriminants --
6198 -----------------------
6200 when Attribute_Has_Discriminants =>
6201 Rewrite (N, New_Occurrence_Of (
6202 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
6203 Analyze_And_Resolve (N, Standard_Boolean);
6205 -----------------------
6206 -- Has_Tagged_Values --
6207 -----------------------
6209 when Attribute_Has_Tagged_Values =>
6210 Rewrite (N, New_Occurrence_Of
6211 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
6212 Analyze_And_Resolve (N, Standard_Boolean);
6218 when Attribute_Identity =>
6225 -- Image is a scalar attribute, but is never static, because it is
6226 -- not a static function (having a non-scalar argument (RM 4.9(22))
6227 -- However, we can constant-fold the image of an enumeration literal
6228 -- if names are available.
6230 when Attribute_Image =>
6231 if Is_Entity_Name (E1)
6232 and then Ekind (Entity (E1)) = E_Enumeration_Literal
6233 and then not Discard_Names (First_Subtype (Etype (E1)))
6234 and then not Global_Discard_Names
6237 Lit : constant Entity_Id := Entity (E1);
6241 Get_Unqualified_Decoded_Name_String (Chars (Lit));
6242 Set_Casing (All_Upper_Case);
6243 Store_String_Chars (Name_Buffer (1 .. Name_Len));
6245 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
6246 Analyze_And_Resolve (N, Standard_String);
6247 Set_Is_Static_Expression (N, False);
6255 -- Img is a scalar attribute, but is never static, because it is
6256 -- not a static function (having a non-scalar argument (RM 4.9(22))
6258 when Attribute_Img =>
6265 -- We never try to fold Integer_Value (though perhaps we could???)
6267 when Attribute_Integer_Value =>
6274 -- Invalid_Value is a scalar attribute that is never static, because
6275 -- the value is by design out of range.
6277 when Attribute_Invalid_Value =>
6284 when Attribute_Large =>
6286 -- For fixed-point, we use the identity:
6288 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6290 if Is_Fixed_Point_Type (P_Type) then
6292 Make_Op_Multiply (Loc,
6294 Make_Op_Subtract (Loc,
6298 Make_Real_Literal (Loc, Ureal_2),
6300 Make_Attribute_Reference (Loc,
6302 Attribute_Name => Name_Mantissa)),
6303 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6306 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6308 Analyze_And_Resolve (N, C_Type);
6310 -- Floating-point (Ada 83 compatibility)
6313 -- Ada 83 attribute is defined as (RM83 3.5.8)
6315 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6319 -- T'Emax = 4 * T'Mantissa
6322 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6330 when Attribute_Last => Last :
6334 if Compile_Time_Known_Value (Hi_Bound) then
6335 if Is_Real_Type (P_Type) then
6336 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6338 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6342 Check_Concurrent_Discriminant (Hi_Bound);
6350 when Attribute_Leading_Part =>
6352 Eval_Fat.Leading_Part
6353 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6359 when Attribute_Length => Length : declare
6363 -- If any index type is a formal type, or derived from one, the
6364 -- bounds are not static. Treating them as static can produce
6365 -- spurious warnings or improper constant folding.
6367 Ind := First_Index (P_Type);
6368 while Present (Ind) loop
6369 if Is_Generic_Type (Root_Type (Etype (Ind))) then
6378 -- For two compile time values, we can compute length
6380 if Compile_Time_Known_Value (Lo_Bound)
6381 and then Compile_Time_Known_Value (Hi_Bound)
6384 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6388 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6389 -- comparable, and we can figure out the difference between them.
6392 Diff : aliased Uint;
6396 Compile_Time_Compare
6397 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6400 Fold_Uint (N, Uint_1, False);
6403 Fold_Uint (N, Uint_0, False);
6406 if Diff /= No_Uint then
6407 Fold_Uint (N, Diff + 1, False);
6420 when Attribute_Machine =>
6423 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6430 when Attribute_Machine_Emax =>
6431 Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
6437 when Attribute_Machine_Emin =>
6438 Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
6440 ----------------------
6441 -- Machine_Mantissa --
6442 ----------------------
6444 when Attribute_Machine_Mantissa =>
6445 Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
6447 -----------------------
6448 -- Machine_Overflows --
6449 -----------------------
6451 when Attribute_Machine_Overflows =>
6453 -- Always true for fixed-point
6455 if Is_Fixed_Point_Type (P_Type) then
6456 Fold_Uint (N, True_Value, True);
6458 -- Floating point case
6462 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6470 when Attribute_Machine_Radix =>
6471 if Is_Fixed_Point_Type (P_Type) then
6472 if Is_Decimal_Fixed_Point_Type (P_Type)
6473 and then Machine_Radix_10 (P_Type)
6475 Fold_Uint (N, Uint_10, True);
6477 Fold_Uint (N, Uint_2, True);
6480 -- All floating-point type always have radix 2
6483 Fold_Uint (N, Uint_2, True);
6486 ----------------------
6487 -- Machine_Rounding --
6488 ----------------------
6490 -- Note: for the folding case, it is fine to treat Machine_Rounding
6491 -- exactly the same way as Rounding, since this is one of the allowed
6492 -- behaviors, and performance is not an issue here. It might be a bit
6493 -- better to give the same result as it would give at run time, even
6494 -- though the non-determinism is certainly permitted.
6496 when Attribute_Machine_Rounding =>
6498 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6500 --------------------
6501 -- Machine_Rounds --
6502 --------------------
6504 when Attribute_Machine_Rounds =>
6506 -- Always False for fixed-point
6508 if Is_Fixed_Point_Type (P_Type) then
6509 Fold_Uint (N, False_Value, True);
6511 -- Else yield proper floating-point result
6515 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6522 -- Note: Machine_Size is identical to Object_Size
6524 when Attribute_Machine_Size => Machine_Size : declare
6525 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6528 if Known_Esize (P_TypeA) then
6529 Fold_Uint (N, Esize (P_TypeA), True);
6537 when Attribute_Mantissa =>
6539 -- Fixed-point mantissa
6541 if Is_Fixed_Point_Type (P_Type) then
6543 -- Compile time foldable case
6545 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6547 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6549 -- The calculation of the obsolete Ada 83 attribute Mantissa
6550 -- is annoying, because of AI00143, quoted here:
6552 -- !question 84-01-10
6554 -- Consider the model numbers for F:
6556 -- type F is delta 1.0 range -7.0 .. 8.0;
6558 -- The wording requires that F'MANTISSA be the SMALLEST
6559 -- integer number for which each bound of the specified
6560 -- range is either a model number or lies at most small
6561 -- distant from a model number. This means F'MANTISSA
6562 -- is required to be 3 since the range -7.0 .. 7.0 fits
6563 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6564 -- number, namely, 7. Is this analysis correct? Note that
6565 -- this implies the upper bound of the range is not
6566 -- represented as a model number.
6568 -- !response 84-03-17
6570 -- The analysis is correct. The upper and lower bounds for
6571 -- a fixed point type can lie outside the range of model
6582 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6583 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6584 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6585 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6587 -- If the Bound is exactly a model number, i.e. a multiple
6588 -- of Small, then we back it off by one to get the integer
6589 -- value that must be representable.
6591 if Small_Value (P_Type) * Max_Man = Bound then
6592 Max_Man := Max_Man - 1;
6595 -- Now find corresponding size = Mantissa value
6598 while 2 ** Siz < Max_Man loop
6602 Fold_Uint (N, Siz, True);
6606 -- The case of dynamic bounds cannot be evaluated at compile
6607 -- time. Instead we use a runtime routine (see Exp_Attr).
6612 -- Floating-point Mantissa
6615 Fold_Uint (N, Mantissa, True);
6622 when Attribute_Max => Max :
6624 if Is_Real_Type (P_Type) then
6626 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6628 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6632 ----------------------------------
6633 -- Max_Alignment_For_Allocation --
6634 ----------------------------------
6636 -- Max_Alignment_For_Allocation is usually the Alignment. However,
6637 -- arrays are allocated with dope, so we need to take into account both
6638 -- the alignment of the array, which comes from the component alignment,
6639 -- and the alignment of the dope. Also, if the alignment is unknown, we
6640 -- use the max (it's OK to be pessimistic).
6642 when Attribute_Max_Alignment_For_Allocation =>
6644 A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
6646 if Known_Alignment (P_Type) and then
6647 (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
6649 A := Alignment (P_Type);
6652 Fold_Uint (N, A, Static);
6655 ----------------------------------
6656 -- Max_Size_In_Storage_Elements --
6657 ----------------------------------
6659 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6660 -- Storage_Unit boundary. We can fold any cases for which the size
6661 -- is known by the front end.
6663 when Attribute_Max_Size_In_Storage_Elements =>
6664 if Known_Esize (P_Type) then
6666 (Esize (P_Type) + System_Storage_Unit - 1) /
6667 System_Storage_Unit,
6671 --------------------
6672 -- Mechanism_Code --
6673 --------------------
6675 when Attribute_Mechanism_Code =>
6679 Mech : Mechanism_Type;
6683 Mech := Mechanism (P_Entity);
6686 Val := UI_To_Int (Expr_Value (E1));
6688 Formal := First_Formal (P_Entity);
6689 for J in 1 .. Val - 1 loop
6690 Next_Formal (Formal);
6692 Mech := Mechanism (Formal);
6696 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6704 when Attribute_Min => Min :
6706 if Is_Real_Type (P_Type) then
6708 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6711 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6719 when Attribute_Mod =>
6721 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6727 when Attribute_Model =>
6729 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
6735 when Attribute_Model_Emin =>
6736 Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
6742 when Attribute_Model_Epsilon =>
6743 Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
6745 --------------------
6746 -- Model_Mantissa --
6747 --------------------
6749 when Attribute_Model_Mantissa =>
6750 Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
6756 when Attribute_Model_Small =>
6757 Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
6763 when Attribute_Modulus =>
6764 Fold_Uint (N, Modulus (P_Type), True);
6766 --------------------
6767 -- Null_Parameter --
6768 --------------------
6770 -- Cannot fold, we know the value sort of, but the whole point is
6771 -- that there is no way to talk about this imaginary value except
6772 -- by using the attribute, so we leave it the way it is.
6774 when Attribute_Null_Parameter =>
6781 -- The Object_Size attribute for a type returns the Esize of the
6782 -- type and can be folded if this value is known.
6784 when Attribute_Object_Size => Object_Size : declare
6785 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6788 if Known_Esize (P_TypeA) then
6789 Fold_Uint (N, Esize (P_TypeA), True);
6793 -------------------------
6794 -- Passed_By_Reference --
6795 -------------------------
6797 -- Scalar types are never passed by reference
6799 when Attribute_Passed_By_Reference =>
6800 Fold_Uint (N, False_Value, True);
6806 when Attribute_Pos =>
6807 Fold_Uint (N, Expr_Value (E1), True);
6813 when Attribute_Pred => Pred :
6815 -- Floating-point case
6817 if Is_Floating_Point_Type (P_Type) then
6819 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
6823 elsif Is_Fixed_Point_Type (P_Type) then
6825 Expr_Value_R (E1) - Small_Value (P_Type), True);
6827 -- Modular integer case (wraps)
6829 elsif Is_Modular_Integer_Type (P_Type) then
6830 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
6832 -- Other scalar cases
6835 pragma Assert (Is_Scalar_Type (P_Type));
6837 if Is_Enumeration_Type (P_Type)
6838 and then Expr_Value (E1) =
6839 Expr_Value (Type_Low_Bound (P_Base_Type))
6841 Apply_Compile_Time_Constraint_Error
6842 (N, "Pred of `&''First`",
6843 CE_Overflow_Check_Failed,
6845 Warn => not Static);
6851 Fold_Uint (N, Expr_Value (E1) - 1, Static);
6859 -- No processing required, because by this stage, Range has been
6860 -- replaced by First .. Last, so this branch can never be taken.
6862 when Attribute_Range =>
6863 raise Program_Error;
6869 when Attribute_Range_Length =>
6872 -- Can fold if both bounds are compile time known
6874 if Compile_Time_Known_Value (Hi_Bound)
6875 and then Compile_Time_Known_Value (Lo_Bound)
6879 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
6883 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6884 -- comparable, and we can figure out the difference between them.
6887 Diff : aliased Uint;
6891 Compile_Time_Compare
6892 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6895 Fold_Uint (N, Uint_1, False);
6898 Fold_Uint (N, Uint_0, False);
6901 if Diff /= No_Uint then
6902 Fold_Uint (N, Diff + 1, False);
6914 when Attribute_Ref =>
6915 Fold_Uint (N, Expr_Value (E1), True);
6921 when Attribute_Remainder => Remainder : declare
6922 X : constant Ureal := Expr_Value_R (E1);
6923 Y : constant Ureal := Expr_Value_R (E2);
6926 if UR_Is_Zero (Y) then
6927 Apply_Compile_Time_Constraint_Error
6928 (N, "division by zero in Remainder",
6929 CE_Overflow_Check_Failed,
6930 Warn => not Static);
6936 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
6943 when Attribute_Round => Round :
6949 -- First we get the (exact result) in units of small
6951 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
6953 -- Now round that exactly to an integer
6955 Si := UR_To_Uint (Sr);
6957 -- Finally the result is obtained by converting back to real
6959 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
6966 when Attribute_Rounding =>
6968 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6974 when Attribute_Safe_Emax =>
6975 Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
6981 when Attribute_Safe_First =>
6982 Fold_Ureal (N, Safe_First_Value (P_Type), Static);
6988 when Attribute_Safe_Large =>
6989 if Is_Fixed_Point_Type (P_Type) then
6991 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
6993 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
7000 when Attribute_Safe_Last =>
7001 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
7007 when Attribute_Safe_Small =>
7009 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
7010 -- for fixed-point, since is the same as Small, but we implement
7011 -- it for backwards compatibility.
7013 if Is_Fixed_Point_Type (P_Type) then
7014 Fold_Ureal (N, Small_Value (P_Type), Static);
7016 -- Ada 83 Safe_Small for floating-point cases
7019 Fold_Ureal (N, Model_Small_Value (P_Type), Static);
7026 when Attribute_Scale =>
7027 Fold_Uint (N, Scale_Value (P_Type), True);
7033 when Attribute_Scaling =>
7036 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
7042 when Attribute_Signed_Zeros =>
7044 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
7050 -- Size attribute returns the RM size. All scalar types can be folded,
7051 -- as well as any types for which the size is known by the front end,
7052 -- including any type for which a size attribute is specified.
7054 when Attribute_Size | Attribute_VADS_Size => Size : declare
7055 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7058 if RM_Size (P_TypeA) /= Uint_0 then
7062 if Id = Attribute_VADS_Size or else Use_VADS_Size then
7064 S : constant Node_Id := Size_Clause (P_TypeA);
7067 -- If a size clause applies, then use the size from it.
7068 -- This is one of the rare cases where we can use the
7069 -- Size_Clause field for a subtype when Has_Size_Clause
7070 -- is False. Consider:
7072 -- type x is range 1 .. 64;
7073 -- for x'size use 12;
7074 -- subtype y is x range 0 .. 3;
7076 -- Here y has a size clause inherited from x, but normally
7077 -- it does not apply, and y'size is 2. However, y'VADS_Size
7078 -- is indeed 12 and not 2.
7081 and then Is_OK_Static_Expression (Expression (S))
7083 Fold_Uint (N, Expr_Value (Expression (S)), True);
7085 -- If no size is specified, then we simply use the object
7086 -- size in the VADS_Size case (e.g. Natural'Size is equal
7087 -- to Integer'Size, not one less).
7090 Fold_Uint (N, Esize (P_TypeA), True);
7094 -- Normal case (Size) in which case we want the RM_Size
7099 Static and then Is_Discrete_Type (P_TypeA));
7108 when Attribute_Small =>
7110 -- The floating-point case is present only for Ada 83 compatibility.
7111 -- Note that strictly this is an illegal addition, since we are
7112 -- extending an Ada 95 defined attribute, but we anticipate an
7113 -- ARG ruling that will permit this.
7115 if Is_Floating_Point_Type (P_Type) then
7117 -- Ada 83 attribute is defined as (RM83 3.5.8)
7119 -- T'Small = 2.0**(-T'Emax - 1)
7123 -- T'Emax = 4 * T'Mantissa
7125 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
7127 -- Normal Ada 95 fixed-point case
7130 Fold_Ureal (N, Small_Value (P_Type), True);
7137 when Attribute_Stream_Size =>
7144 when Attribute_Succ => Succ :
7146 -- Floating-point case
7148 if Is_Floating_Point_Type (P_Type) then
7150 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
7154 elsif Is_Fixed_Point_Type (P_Type) then
7156 Expr_Value_R (E1) + Small_Value (P_Type), Static);
7158 -- Modular integer case (wraps)
7160 elsif Is_Modular_Integer_Type (P_Type) then
7161 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
7163 -- Other scalar cases
7166 pragma Assert (Is_Scalar_Type (P_Type));
7168 if Is_Enumeration_Type (P_Type)
7169 and then Expr_Value (E1) =
7170 Expr_Value (Type_High_Bound (P_Base_Type))
7172 Apply_Compile_Time_Constraint_Error
7173 (N, "Succ of `&''Last`",
7174 CE_Overflow_Check_Failed,
7176 Warn => not Static);
7181 Fold_Uint (N, Expr_Value (E1) + 1, Static);
7190 when Attribute_Truncation =>
7192 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
7198 when Attribute_Type_Class => Type_Class : declare
7199 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
7203 if Is_Descendent_Of_Address (Typ) then
7204 Id := RE_Type_Class_Address;
7206 elsif Is_Enumeration_Type (Typ) then
7207 Id := RE_Type_Class_Enumeration;
7209 elsif Is_Integer_Type (Typ) then
7210 Id := RE_Type_Class_Integer;
7212 elsif Is_Fixed_Point_Type (Typ) then
7213 Id := RE_Type_Class_Fixed_Point;
7215 elsif Is_Floating_Point_Type (Typ) then
7216 Id := RE_Type_Class_Floating_Point;
7218 elsif Is_Array_Type (Typ) then
7219 Id := RE_Type_Class_Array;
7221 elsif Is_Record_Type (Typ) then
7222 Id := RE_Type_Class_Record;
7224 elsif Is_Access_Type (Typ) then
7225 Id := RE_Type_Class_Access;
7227 elsif Is_Enumeration_Type (Typ) then
7228 Id := RE_Type_Class_Enumeration;
7230 elsif Is_Task_Type (Typ) then
7231 Id := RE_Type_Class_Task;
7233 -- We treat protected types like task types. It would make more
7234 -- sense to have another enumeration value, but after all the
7235 -- whole point of this feature is to be exactly DEC compatible,
7236 -- and changing the type Type_Class would not meet this requirement.
7238 elsif Is_Protected_Type (Typ) then
7239 Id := RE_Type_Class_Task;
7241 -- Not clear if there are any other possibilities, but if there
7242 -- are, then we will treat them as the address case.
7245 Id := RE_Type_Class_Address;
7248 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
7251 -----------------------
7252 -- Unbiased_Rounding --
7253 -----------------------
7255 when Attribute_Unbiased_Rounding =>
7257 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7260 -------------------------
7261 -- Unconstrained_Array --
7262 -------------------------
7264 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7265 Typ : constant Entity_Id := Underlying_Type (P_Type);
7268 Rewrite (N, New_Occurrence_Of (
7270 Is_Array_Type (P_Type)
7271 and then not Is_Constrained (Typ)), Loc));
7273 -- Analyze and resolve as boolean, note that this attribute is
7274 -- a static attribute in GNAT.
7276 Analyze_And_Resolve (N, Standard_Boolean);
7278 end Unconstrained_Array;
7284 -- Processing is shared with Size
7290 when Attribute_Val => Val :
7292 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7294 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7296 Apply_Compile_Time_Constraint_Error
7297 (N, "Val expression out of range",
7298 CE_Range_Check_Failed,
7299 Warn => not Static);
7305 Fold_Uint (N, Expr_Value (E1), Static);
7313 -- The Value_Size attribute for a type returns the RM size of the
7314 -- type. This an always be folded for scalar types, and can also
7315 -- be folded for non-scalar types if the size is set.
7317 when Attribute_Value_Size => Value_Size : declare
7318 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7320 if RM_Size (P_TypeA) /= Uint_0 then
7321 Fold_Uint (N, RM_Size (P_TypeA), True);
7329 -- Version can never be static
7331 when Attribute_Version =>
7338 -- Wide_Image is a scalar attribute, but is never static, because it
7339 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7341 when Attribute_Wide_Image =>
7344 ---------------------
7345 -- Wide_Wide_Image --
7346 ---------------------
7348 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7349 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7351 when Attribute_Wide_Wide_Image =>
7354 ---------------------
7355 -- Wide_Wide_Width --
7356 ---------------------
7358 -- Processing for Wide_Wide_Width is combined with Width
7364 -- Processing for Wide_Width is combined with Width
7370 -- This processing also handles the case of Wide_[Wide_]Width
7372 when Attribute_Width |
7373 Attribute_Wide_Width |
7374 Attribute_Wide_Wide_Width => Width :
7376 if Compile_Time_Known_Bounds (P_Type) then
7378 -- Floating-point types
7380 if Is_Floating_Point_Type (P_Type) then
7382 -- Width is zero for a null range (RM 3.5 (38))
7384 if Expr_Value_R (Type_High_Bound (P_Type)) <
7385 Expr_Value_R (Type_Low_Bound (P_Type))
7387 Fold_Uint (N, Uint_0, True);
7390 -- For floating-point, we have +N.dddE+nnn where length
7391 -- of ddd is determined by type'Digits - 1, but is one
7392 -- if Digits is one (RM 3.5 (33)).
7394 -- nnn is set to 2 for Short_Float and Float (32 bit
7395 -- floats), and 3 for Long_Float and Long_Long_Float.
7396 -- For machines where Long_Long_Float is the IEEE
7397 -- extended precision type, the exponent takes 4 digits.
7401 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7404 if Esize (P_Type) <= 32 then
7406 elsif Esize (P_Type) = 64 then
7412 Fold_Uint (N, UI_From_Int (Len), True);
7416 -- Fixed-point types
7418 elsif Is_Fixed_Point_Type (P_Type) then
7420 -- Width is zero for a null range (RM 3.5 (38))
7422 if Expr_Value (Type_High_Bound (P_Type)) <
7423 Expr_Value (Type_Low_Bound (P_Type))
7425 Fold_Uint (N, Uint_0, True);
7427 -- The non-null case depends on the specific real type
7430 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7433 (N, UI_From_Int (Fore_Value + 1) + Aft_Value (P_Type),
7441 R : constant Entity_Id := Root_Type (P_Type);
7442 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7443 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7456 -- Width for types derived from Standard.Character
7457 -- and Standard.Wide_[Wide_]Character.
7459 elsif Is_Standard_Character_Type (P_Type) then
7462 -- Set W larger if needed
7464 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7466 -- All wide characters look like Hex_hhhhhhhh
7470 -- No need to compute this more than once!
7475 C := Character'Val (J);
7477 -- Test for all cases where Character'Image
7478 -- yields an image that is longer than three
7479 -- characters. First the cases of Reserved_xxx
7480 -- names (length = 12).
7483 when Reserved_128 | Reserved_129 |
7484 Reserved_132 | Reserved_153
7487 when BS | HT | LF | VT | FF | CR |
7488 SO | SI | EM | FS | GS | RS |
7489 US | RI | MW | ST | PM
7492 when NUL | SOH | STX | ETX | EOT |
7493 ENQ | ACK | BEL | DLE | DC1 |
7494 DC2 | DC3 | DC4 | NAK | SYN |
7495 ETB | CAN | SUB | ESC | DEL |
7496 BPH | NBH | NEL | SSA | ESA |
7497 HTS | HTJ | VTS | PLD | PLU |
7498 SS2 | SS3 | DCS | PU1 | PU2 |
7499 STS | CCH | SPA | EPA | SOS |
7500 SCI | CSI | OSC | APC
7503 when Space .. Tilde |
7504 No_Break_Space .. LC_Y_Diaeresis
7506 -- Special case of soft hyphen in Ada 2005
7508 if C = Character'Val (16#AD#)
7509 and then Ada_Version >= Ada_2005
7517 W := Int'Max (W, Wt);
7521 -- Width for types derived from Standard.Boolean
7523 elsif R = Standard_Boolean then
7530 -- Width for integer types
7532 elsif Is_Integer_Type (P_Type) then
7533 T := UI_Max (abs Lo, abs Hi);
7541 -- Only remaining possibility is user declared enum type
7544 pragma Assert (Is_Enumeration_Type (P_Type));
7547 L := First_Literal (P_Type);
7549 while Present (L) loop
7551 -- Only pay attention to in range characters
7553 if Lo <= Enumeration_Pos (L)
7554 and then Enumeration_Pos (L) <= Hi
7556 -- For Width case, use decoded name
7558 if Id = Attribute_Width then
7559 Get_Decoded_Name_String (Chars (L));
7560 Wt := Nat (Name_Len);
7562 -- For Wide_[Wide_]Width, use encoded name, and
7563 -- then adjust for the encoding.
7566 Get_Name_String (Chars (L));
7568 -- Character literals are always of length 3
7570 if Name_Buffer (1) = 'Q' then
7573 -- Otherwise loop to adjust for upper/wide chars
7576 Wt := Nat (Name_Len);
7578 for J in 1 .. Name_Len loop
7579 if Name_Buffer (J) = 'U' then
7581 elsif Name_Buffer (J) = 'W' then
7588 W := Int'Max (W, Wt);
7595 Fold_Uint (N, UI_From_Int (W), True);
7601 -- The following attributes denote functions that cannot be folded
7603 when Attribute_From_Any |
7605 Attribute_TypeCode =>
7608 -- The following attributes can never be folded, and furthermore we
7609 -- should not even have entered the case statement for any of these.
7610 -- Note that in some cases, the values have already been folded as
7611 -- a result of the processing in Analyze_Attribute.
7613 when Attribute_Abort_Signal |
7616 Attribute_Address_Size |
7617 Attribute_Asm_Input |
7618 Attribute_Asm_Output |
7620 Attribute_Bit_Order |
7621 Attribute_Bit_Position |
7622 Attribute_Callable |
7625 Attribute_Code_Address |
7626 Attribute_Compiler_Version |
7628 Attribute_Default_Bit_Order |
7629 Attribute_Elaborated |
7630 Attribute_Elab_Body |
7631 Attribute_Elab_Spec |
7633 Attribute_External_Tag |
7634 Attribute_Fast_Math |
7635 Attribute_First_Bit |
7637 Attribute_Last_Bit |
7638 Attribute_Maximum_Alignment |
7641 Attribute_Partition_ID |
7642 Attribute_Pool_Address |
7643 Attribute_Position |
7644 Attribute_Priority |
7647 Attribute_Storage_Pool |
7648 Attribute_Storage_Size |
7649 Attribute_Storage_Unit |
7650 Attribute_Stub_Type |
7652 Attribute_Target_Name |
7653 Attribute_Terminated |
7654 Attribute_To_Address |
7655 Attribute_Type_Key |
7656 Attribute_UET_Address |
7657 Attribute_Unchecked_Access |
7658 Attribute_Universal_Literal_String |
7659 Attribute_Unrestricted_Access |
7662 Attribute_Wchar_T_Size |
7663 Attribute_Wide_Value |
7664 Attribute_Wide_Wide_Value |
7665 Attribute_Word_Size |
7668 raise Program_Error;
7671 -- At the end of the case, one more check. If we did a static evaluation
7672 -- so that the result is now a literal, then set Is_Static_Expression
7673 -- in the constant only if the prefix type is a static subtype. For
7674 -- non-static subtypes, the folding is still OK, but not static.
7676 -- An exception is the GNAT attribute Constrained_Array which is
7677 -- defined to be a static attribute in all cases.
7679 if Nkind_In (N, N_Integer_Literal,
7681 N_Character_Literal,
7683 or else (Is_Entity_Name (N)
7684 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7686 Set_Is_Static_Expression (N, Static);
7688 -- If this is still an attribute reference, then it has not been folded
7689 -- and that means that its expressions are in a non-static context.
7691 elsif Nkind (N) = N_Attribute_Reference then
7694 -- Note: the else case not covered here are odd cases where the
7695 -- processing has transformed the attribute into something other
7696 -- than a constant. Nothing more to do in such cases.
7703 ------------------------------
7704 -- Is_Anonymous_Tagged_Base --
7705 ------------------------------
7707 function Is_Anonymous_Tagged_Base
7714 Anon = Current_Scope
7715 and then Is_Itype (Anon)
7716 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
7717 end Is_Anonymous_Tagged_Base;
7719 --------------------------------
7720 -- Name_Implies_Lvalue_Prefix --
7721 --------------------------------
7723 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
7724 pragma Assert (Is_Attribute_Name (Nam));
7726 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
7727 end Name_Implies_Lvalue_Prefix;
7729 -----------------------
7730 -- Resolve_Attribute --
7731 -----------------------
7733 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
7734 Loc : constant Source_Ptr := Sloc (N);
7735 P : constant Node_Id := Prefix (N);
7736 Aname : constant Name_Id := Attribute_Name (N);
7737 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7738 Btyp : constant Entity_Id := Base_Type (Typ);
7739 Des_Btyp : Entity_Id;
7740 Index : Interp_Index;
7742 Nom_Subt : Entity_Id;
7744 procedure Accessibility_Message;
7745 -- Error, or warning within an instance, if the static accessibility
7746 -- rules of 3.10.2 are violated.
7748 ---------------------------
7749 -- Accessibility_Message --
7750 ---------------------------
7752 procedure Accessibility_Message is
7753 Indic : Node_Id := Parent (Parent (N));
7756 -- In an instance, this is a runtime check, but one we
7757 -- know will fail, so generate an appropriate warning.
7759 if In_Instance_Body then
7760 Error_Msg_F ("?non-local pointer cannot point to local object", P);
7762 ("\?Program_Error will be raised at run time", P);
7764 Make_Raise_Program_Error (Loc,
7765 Reason => PE_Accessibility_Check_Failed));
7770 Error_Msg_F ("non-local pointer cannot point to local object", P);
7772 -- Check for case where we have a missing access definition
7774 if Is_Record_Type (Current_Scope)
7776 Nkind_In (Parent (N), N_Discriminant_Association,
7777 N_Index_Or_Discriminant_Constraint)
7779 Indic := Parent (Parent (N));
7780 while Present (Indic)
7781 and then Nkind (Indic) /= N_Subtype_Indication
7783 Indic := Parent (Indic);
7786 if Present (Indic) then
7788 ("\use an access definition for" &
7789 " the access discriminant of&",
7790 N, Entity (Subtype_Mark (Indic)));
7794 end Accessibility_Message;
7796 -- Start of processing for Resolve_Attribute
7799 -- If error during analysis, no point in continuing, except for array
7800 -- types, where we get better recovery by using unconstrained indexes
7801 -- than nothing at all (see Check_Array_Type).
7804 and then Attr_Id /= Attribute_First
7805 and then Attr_Id /= Attribute_Last
7806 and then Attr_Id /= Attribute_Length
7807 and then Attr_Id /= Attribute_Range
7812 -- If attribute was universal type, reset to actual type
7814 if Etype (N) = Universal_Integer
7815 or else Etype (N) = Universal_Real
7820 -- Remaining processing depends on attribute
7828 -- For access attributes, if the prefix denotes an entity, it is
7829 -- interpreted as a name, never as a call. It may be overloaded,
7830 -- in which case resolution uses the profile of the context type.
7831 -- Otherwise prefix must be resolved.
7833 when Attribute_Access
7834 | Attribute_Unchecked_Access
7835 | Attribute_Unrestricted_Access =>
7839 if Is_Variable (P) then
7840 Note_Possible_Modification (P, Sure => False);
7843 -- The following comes from a query by Adam Beneschan, concerning
7844 -- improper use of universal_access in equality tests involving
7845 -- anonymous access types. Another good reason for 'Ref, but
7846 -- for now disable the test, which breaks several filed tests.
7848 if Ekind (Typ) = E_Anonymous_Access_Type
7849 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
7852 Error_Msg_N ("need unique type to resolve 'Access", N);
7853 Error_Msg_N ("\qualify attribute with some access type", N);
7856 if Is_Entity_Name (P) then
7857 if Is_Overloaded (P) then
7858 Get_First_Interp (P, Index, It);
7859 while Present (It.Nam) loop
7860 if Type_Conformant (Designated_Type (Typ), It.Nam) then
7861 Set_Entity (P, It.Nam);
7863 -- The prefix is definitely NOT overloaded anymore at
7864 -- this point, so we reset the Is_Overloaded flag to
7865 -- avoid any confusion when reanalyzing the node.
7867 Set_Is_Overloaded (P, False);
7868 Set_Is_Overloaded (N, False);
7869 Generate_Reference (Entity (P), P);
7873 Get_Next_Interp (Index, It);
7876 -- If Prefix is a subprogram name, it is frozen by this
7879 -- If it is a type, there is nothing to resolve.
7880 -- If it is an object, complete its resolution.
7882 elsif Is_Overloadable (Entity (P)) then
7884 -- Avoid insertion of freeze actions in spec expression mode
7886 if not In_Spec_Expression then
7887 Freeze_Before (N, Entity (P));
7890 elsif Is_Type (Entity (P)) then
7896 Error_Msg_Name_1 := Aname;
7898 if not Is_Entity_Name (P) then
7901 elsif Is_Overloadable (Entity (P))
7902 and then Is_Abstract_Subprogram (Entity (P))
7904 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
7905 Set_Etype (N, Any_Type);
7907 elsif Convention (Entity (P)) = Convention_Intrinsic then
7908 if Ekind (Entity (P)) = E_Enumeration_Literal then
7910 ("prefix of % attribute cannot be enumeration literal",
7914 ("prefix of % attribute cannot be intrinsic", P);
7917 Set_Etype (N, Any_Type);
7920 -- Assignments, return statements, components of aggregates,
7921 -- generic instantiations will require convention checks if
7922 -- the type is an access to subprogram. Given that there will
7923 -- also be accessibility checks on those, this is where the
7924 -- checks can eventually be centralized ???
7926 if Ekind_In (Btyp, E_Access_Subprogram_Type,
7927 E_Anonymous_Access_Subprogram_Type,
7928 E_Access_Protected_Subprogram_Type,
7929 E_Anonymous_Access_Protected_Subprogram_Type)
7931 -- Deal with convention mismatch
7933 if Convention (Designated_Type (Btyp)) /=
7934 Convention (Entity (P))
7937 ("subprogram & has wrong convention", P, Entity (P));
7939 ("\does not match convention of access type &",
7942 if not Has_Convention_Pragma (Btyp) then
7944 ("\probable missing pragma Convention for &",
7949 Check_Subtype_Conformant
7950 (New_Id => Entity (P),
7951 Old_Id => Designated_Type (Btyp),
7955 if Attr_Id = Attribute_Unchecked_Access then
7956 Error_Msg_Name_1 := Aname;
7958 ("attribute% cannot be applied to a subprogram", P);
7960 elsif Aname = Name_Unrestricted_Access then
7961 null; -- Nothing to check
7963 -- Check the static accessibility rule of 3.10.2(32).
7964 -- This rule also applies within the private part of an
7965 -- instantiation. This rule does not apply to anonymous
7966 -- access-to-subprogram types in access parameters.
7968 elsif Attr_Id = Attribute_Access
7969 and then not In_Instance_Body
7971 (Ekind (Btyp) = E_Access_Subprogram_Type
7972 or else Is_Local_Anonymous_Access (Btyp))
7974 and then Subprogram_Access_Level (Entity (P)) >
7975 Type_Access_Level (Btyp)
7978 ("subprogram must not be deeper than access type", P);
7980 -- Check the restriction of 3.10.2(32) that disallows the
7981 -- access attribute within a generic body when the ultimate
7982 -- ancestor of the type of the attribute is declared outside
7983 -- of the generic unit and the subprogram is declared within
7984 -- that generic unit. This includes any such attribute that
7985 -- occurs within the body of a generic unit that is a child
7986 -- of the generic unit where the subprogram is declared.
7988 -- The rule also prohibits applying the attribute when the
7989 -- access type is a generic formal access type (since the
7990 -- level of the actual type is not known). This restriction
7991 -- does not apply when the attribute type is an anonymous
7992 -- access-to-subprogram type. Note that this check was
7993 -- revised by AI-229, because the originally Ada 95 rule
7994 -- was too lax. The original rule only applied when the
7995 -- subprogram was declared within the body of the generic,
7996 -- which allowed the possibility of dangling references).
7997 -- The rule was also too strict in some case, in that it
7998 -- didn't permit the access to be declared in the generic
7999 -- spec, whereas the revised rule does (as long as it's not
8002 -- There are a couple of subtleties of the test for applying
8003 -- the check that are worth noting. First, we only apply it
8004 -- when the levels of the subprogram and access type are the
8005 -- same (the case where the subprogram is statically deeper
8006 -- was applied above, and the case where the type is deeper
8007 -- is always safe). Second, we want the check to apply
8008 -- within nested generic bodies and generic child unit
8009 -- bodies, but not to apply to an attribute that appears in
8010 -- the generic unit's specification. This is done by testing
8011 -- that the attribute's innermost enclosing generic body is
8012 -- not the same as the innermost generic body enclosing the
8013 -- generic unit where the subprogram is declared (we don't
8014 -- want the check to apply when the access attribute is in
8015 -- the spec and there's some other generic body enclosing
8016 -- generic). Finally, there's no point applying the check
8017 -- when within an instance, because any violations will have
8018 -- been caught by the compilation of the generic unit.
8020 -- Note that we relax this check in CodePeer mode for
8021 -- compatibility with legacy code, since CodePeer is an
8022 -- Ada source code analyzer, not a strict compiler.
8023 -- ??? Note that a better approach would be to have a
8024 -- separate switch to relax this rule, and enable this
8025 -- switch in CodePeer mode.
8027 elsif Attr_Id = Attribute_Access
8028 and then not CodePeer_Mode
8029 and then not In_Instance
8030 and then Present (Enclosing_Generic_Unit (Entity (P)))
8031 and then Present (Enclosing_Generic_Body (N))
8032 and then Enclosing_Generic_Body (N) /=
8033 Enclosing_Generic_Body
8034 (Enclosing_Generic_Unit (Entity (P)))
8035 and then Subprogram_Access_Level (Entity (P)) =
8036 Type_Access_Level (Btyp)
8037 and then Ekind (Btyp) /=
8038 E_Anonymous_Access_Subprogram_Type
8039 and then Ekind (Btyp) /=
8040 E_Anonymous_Access_Protected_Subprogram_Type
8042 -- The attribute type's ultimate ancestor must be
8043 -- declared within the same generic unit as the
8044 -- subprogram is declared. The error message is
8045 -- specialized to say "ancestor" for the case where the
8046 -- access type is not its own ancestor, since saying
8047 -- simply "access type" would be very confusing.
8049 if Enclosing_Generic_Unit (Entity (P)) /=
8050 Enclosing_Generic_Unit (Root_Type (Btyp))
8053 ("''Access attribute not allowed in generic body",
8056 if Root_Type (Btyp) = Btyp then
8059 "access type & is declared outside " &
8060 "generic unit (RM 3.10.2(32))", N, Btyp);
8063 ("\because ancestor of " &
8064 "access type & is declared outside " &
8065 "generic unit (RM 3.10.2(32))", N, Btyp);
8069 ("\move ''Access to private part, or " &
8070 "(Ada 2005) use anonymous access type instead of &",
8073 -- If the ultimate ancestor of the attribute's type is
8074 -- a formal type, then the attribute is illegal because
8075 -- the actual type might be declared at a higher level.
8076 -- The error message is specialized to say "ancestor"
8077 -- for the case where the access type is not its own
8078 -- ancestor, since saying simply "access type" would be
8081 elsif Is_Generic_Type (Root_Type (Btyp)) then
8082 if Root_Type (Btyp) = Btyp then
8084 ("access type must not be a generic formal type",
8088 ("ancestor access type must not be a generic " &
8095 -- If this is a renaming, an inherited operation, or a
8096 -- subprogram instance, use the original entity. This may make
8097 -- the node type-inconsistent, so this transformation can only
8098 -- be done if the node will not be reanalyzed. In particular,
8099 -- if it is within a default expression, the transformation
8100 -- must be delayed until the default subprogram is created for
8101 -- it, when the enclosing subprogram is frozen.
8103 if Is_Entity_Name (P)
8104 and then Is_Overloadable (Entity (P))
8105 and then Present (Alias (Entity (P)))
8106 and then Expander_Active
8109 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8112 elsif Nkind (P) = N_Selected_Component
8113 and then Is_Overloadable (Entity (Selector_Name (P)))
8115 -- Protected operation. If operation is overloaded, must
8116 -- disambiguate. Prefix that denotes protected object itself
8117 -- is resolved with its own type.
8119 if Attr_Id = Attribute_Unchecked_Access then
8120 Error_Msg_Name_1 := Aname;
8122 ("attribute% cannot be applied to protected operation", P);
8125 Resolve (Prefix (P));
8126 Generate_Reference (Entity (Selector_Name (P)), P);
8128 elsif Is_Overloaded (P) then
8130 -- Use the designated type of the context to disambiguate
8131 -- Note that this was not strictly conformant to Ada 95,
8132 -- but was the implementation adopted by most Ada 95 compilers.
8133 -- The use of the context type to resolve an Access attribute
8134 -- reference is now mandated in AI-235 for Ada 2005.
8137 Index : Interp_Index;
8141 Get_First_Interp (P, Index, It);
8142 while Present (It.Typ) loop
8143 if Covers (Designated_Type (Typ), It.Typ) then
8144 Resolve (P, It.Typ);
8148 Get_Next_Interp (Index, It);
8155 -- X'Access is illegal if X denotes a constant and the access type
8156 -- is access-to-variable. Same for 'Unchecked_Access. The rule
8157 -- does not apply to 'Unrestricted_Access. If the reference is a
8158 -- default-initialized aggregate component for a self-referential
8159 -- type the reference is legal.
8161 if not (Ekind (Btyp) = E_Access_Subprogram_Type
8162 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
8163 or else (Is_Record_Type (Btyp)
8165 Present (Corresponding_Remote_Type (Btyp)))
8166 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8167 or else Ekind (Btyp)
8168 = E_Anonymous_Access_Protected_Subprogram_Type
8169 or else Is_Access_Constant (Btyp)
8170 or else Is_Variable (P)
8171 or else Attr_Id = Attribute_Unrestricted_Access)
8173 if Is_Entity_Name (P)
8174 and then Is_Type (Entity (P))
8176 -- Legality of a self-reference through an access
8177 -- attribute has been verified in Analyze_Access_Attribute.
8181 elsif Comes_From_Source (N) then
8182 Error_Msg_F ("access-to-variable designates constant", P);
8186 Des_Btyp := Designated_Type (Btyp);
8188 if Ada_Version >= Ada_2005
8189 and then Is_Incomplete_Type (Des_Btyp)
8191 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
8192 -- imported entity, and the non-limited view is visible, make
8193 -- use of it. If it is an incomplete subtype, use the base type
8196 if From_With_Type (Des_Btyp)
8197 and then Present (Non_Limited_View (Des_Btyp))
8199 Des_Btyp := Non_Limited_View (Des_Btyp);
8201 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
8202 Des_Btyp := Etype (Des_Btyp);
8206 if (Attr_Id = Attribute_Access
8208 Attr_Id = Attribute_Unchecked_Access)
8209 and then (Ekind (Btyp) = E_General_Access_Type
8210 or else Ekind (Btyp) = E_Anonymous_Access_Type)
8212 -- Ada 2005 (AI-230): Check the accessibility of anonymous
8213 -- access types for stand-alone objects, record and array
8214 -- components, and return objects. For a component definition
8215 -- the level is the same of the enclosing composite type.
8217 if Ada_Version >= Ada_2005
8218 and then Is_Local_Anonymous_Access (Btyp)
8219 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8220 and then Attr_Id = Attribute_Access
8222 -- In an instance, this is a runtime check, but one we
8223 -- know will fail, so generate an appropriate warning.
8225 if In_Instance_Body then
8227 ("?non-local pointer cannot point to local object", P);
8229 ("\?Program_Error will be raised at run time", P);
8231 Make_Raise_Program_Error (Loc,
8232 Reason => PE_Accessibility_Check_Failed));
8237 ("non-local pointer cannot point to local object", P);
8241 if Is_Dependent_Component_Of_Mutable_Object (P) then
8243 ("illegal attribute for discriminant-dependent component",
8247 -- Check static matching rule of 3.10.2(27). Nominal subtype
8248 -- of the prefix must statically match the designated type.
8250 Nom_Subt := Etype (P);
8252 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
8253 Nom_Subt := Base_Type (Nom_Subt);
8256 if Is_Tagged_Type (Designated_Type (Typ)) then
8258 -- If the attribute is in the context of an access
8259 -- parameter, then the prefix is allowed to be of the
8260 -- class-wide type (by AI-127).
8262 if Ekind (Typ) = E_Anonymous_Access_Type then
8263 if not Covers (Designated_Type (Typ), Nom_Subt)
8264 and then not Covers (Nom_Subt, Designated_Type (Typ))
8270 Desig := Designated_Type (Typ);
8272 if Is_Class_Wide_Type (Desig) then
8273 Desig := Etype (Desig);
8276 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8281 ("type of prefix: & not compatible",
8284 ("\with &, the expected designated type",
8285 P, Designated_Type (Typ));
8290 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8292 (not Is_Class_Wide_Type (Designated_Type (Typ))
8293 and then Is_Class_Wide_Type (Nom_Subt))
8296 ("type of prefix: & is not covered", P, Nom_Subt);
8298 ("\by &, the expected designated type" &
8299 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8302 if Is_Class_Wide_Type (Designated_Type (Typ))
8303 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8304 and then Is_Constrained (Etype (Designated_Type (Typ)))
8305 and then Designated_Type (Typ) /= Nom_Subt
8307 Apply_Discriminant_Check
8308 (N, Etype (Designated_Type (Typ)));
8311 -- Ada 2005 (AI-363): Require static matching when designated
8312 -- type has discriminants and a constrained partial view, since
8313 -- in general objects of such types are mutable, so we can't
8314 -- allow the access value to designate a constrained object
8315 -- (because access values must be assumed to designate mutable
8316 -- objects when designated type does not impose a constraint).
8318 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8321 elsif Has_Discriminants (Designated_Type (Typ))
8322 and then not Is_Constrained (Des_Btyp)
8324 (Ada_Version < Ada_2005
8326 not Has_Constrained_Partial_View
8327 (Designated_Type (Base_Type (Typ))))
8333 ("object subtype must statically match "
8334 & "designated subtype", P);
8336 if Is_Entity_Name (P)
8337 and then Is_Array_Type (Designated_Type (Typ))
8340 D : constant Node_Id := Declaration_Node (Entity (P));
8343 Error_Msg_N ("aliased object has explicit bounds?",
8345 Error_Msg_N ("\declare without bounds"
8346 & " (and with explicit initialization)?", D);
8347 Error_Msg_N ("\for use with unconstrained access?", D);
8352 -- Check the static accessibility rule of 3.10.2(28).
8353 -- Note that this check is not performed for the
8354 -- case of an anonymous access type, since the access
8355 -- attribute is always legal in such a context.
8357 if Attr_Id /= Attribute_Unchecked_Access
8358 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8359 and then Ekind (Btyp) = E_General_Access_Type
8361 Accessibility_Message;
8366 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
8367 E_Anonymous_Access_Protected_Subprogram_Type)
8369 if Is_Entity_Name (P)
8370 and then not Is_Protected_Type (Scope (Entity (P)))
8372 Error_Msg_F ("context requires a protected subprogram", P);
8374 -- Check accessibility of protected object against that of the
8375 -- access type, but only on user code, because the expander
8376 -- creates access references for handlers. If the context is an
8377 -- anonymous_access_to_protected, there are no accessibility
8378 -- checks either. Omit check entirely for Unrestricted_Access.
8380 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8381 and then Comes_From_Source (N)
8382 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8383 and then Attr_Id /= Attribute_Unrestricted_Access
8385 Accessibility_Message;
8389 elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
8390 E_Anonymous_Access_Subprogram_Type)
8391 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8393 Error_Msg_F ("context requires a non-protected subprogram", P);
8396 -- The context cannot be a pool-specific type, but this is a
8397 -- legality rule, not a resolution rule, so it must be checked
8398 -- separately, after possibly disambiguation (see AI-245).
8400 if Ekind (Btyp) = E_Access_Type
8401 and then Attr_Id /= Attribute_Unrestricted_Access
8403 Wrong_Type (N, Typ);
8406 -- The context may be a constrained access type (however ill-
8407 -- advised such subtypes might be) so in order to generate a
8408 -- constraint check when needed set the type of the attribute
8409 -- reference to the base type of the context.
8411 Set_Etype (N, Btyp);
8413 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8415 if Attr_Id /= Attribute_Unrestricted_Access then
8416 if Is_Atomic_Object (P)
8417 and then not Is_Atomic (Designated_Type (Typ))
8420 ("access to atomic object cannot yield access-to-" &
8421 "non-atomic type", P);
8423 elsif Is_Volatile_Object (P)
8424 and then not Is_Volatile (Designated_Type (Typ))
8427 ("access to volatile object cannot yield access-to-" &
8428 "non-volatile type", P);
8432 if Is_Entity_Name (P) then
8433 Set_Address_Taken (Entity (P));
8435 end Access_Attribute;
8441 -- Deal with resolving the type for Address attribute, overloading
8442 -- is not permitted here, since there is no context to resolve it.
8444 when Attribute_Address | Attribute_Code_Address =>
8445 Address_Attribute : begin
8447 -- To be safe, assume that if the address of a variable is taken,
8448 -- it may be modified via this address, so note modification.
8450 if Is_Variable (P) then
8451 Note_Possible_Modification (P, Sure => False);
8454 if Nkind (P) in N_Subexpr
8455 and then Is_Overloaded (P)
8457 Get_First_Interp (P, Index, It);
8458 Get_Next_Interp (Index, It);
8460 if Present (It.Nam) then
8461 Error_Msg_Name_1 := Aname;
8463 ("prefix of % attribute cannot be overloaded", P);
8467 if not Is_Entity_Name (P)
8468 or else not Is_Overloadable (Entity (P))
8470 if not Is_Task_Type (Etype (P))
8471 or else Nkind (P) = N_Explicit_Dereference
8477 -- If this is the name of a derived subprogram, or that of a
8478 -- generic actual, the address is that of the original entity.
8480 if Is_Entity_Name (P)
8481 and then Is_Overloadable (Entity (P))
8482 and then Present (Alias (Entity (P)))
8485 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8488 if Is_Entity_Name (P) then
8489 Set_Address_Taken (Entity (P));
8492 if Nkind (P) = N_Slice then
8494 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8495 -- even if the array is packed and the slice itself is not
8496 -- addressable. Transform the prefix into an indexed component.
8498 -- Note that the transformation is safe only if we know that
8499 -- the slice is non-null. That is because a null slice can have
8500 -- an out of bounds index value.
8502 -- Right now, gigi blows up if given 'Address on a slice as a
8503 -- result of some incorrect freeze nodes generated by the front
8504 -- end, and this covers up that bug in one case, but the bug is
8505 -- likely still there in the cases not handled by this code ???
8507 -- It's not clear what 'Address *should* return for a null
8508 -- slice with out of bounds indexes, this might be worth an ARG
8511 -- One approach would be to do a length check unconditionally,
8512 -- and then do the transformation below unconditionally, but
8513 -- analyze with checks off, avoiding the problem of the out of
8514 -- bounds index. This approach would interpret the address of
8515 -- an out of bounds null slice as being the address where the
8516 -- array element would be if there was one, which is probably
8517 -- as reasonable an interpretation as any ???
8520 Loc : constant Source_Ptr := Sloc (P);
8521 D : constant Node_Id := Discrete_Range (P);
8525 if Is_Entity_Name (D)
8528 (Type_Low_Bound (Entity (D)),
8529 Type_High_Bound (Entity (D)))
8532 Make_Attribute_Reference (Loc,
8533 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8534 Attribute_Name => Name_First);
8536 elsif Nkind (D) = N_Range
8537 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8539 Lo := Low_Bound (D);
8545 if Present (Lo) then
8547 Make_Indexed_Component (Loc,
8548 Prefix => Relocate_Node (Prefix (P)),
8549 Expressions => New_List (Lo)));
8551 Analyze_And_Resolve (P);
8555 end Address_Attribute;
8561 -- Prefix of the AST_Entry attribute is an entry name which must
8562 -- not be resolved, since this is definitely not an entry call.
8564 when Attribute_AST_Entry =>
8571 -- Prefix of Body_Version attribute can be a subprogram name which
8572 -- must not be resolved, since this is not a call.
8574 when Attribute_Body_Version =>
8581 -- Prefix of Caller attribute is an entry name which must not
8582 -- be resolved, since this is definitely not an entry call.
8584 when Attribute_Caller =>
8591 -- Shares processing with Address attribute
8597 -- If the prefix of the Count attribute is an entry name it must not
8598 -- be resolved, since this is definitely not an entry call. However,
8599 -- if it is an element of an entry family, the index itself may
8600 -- have to be resolved because it can be a general expression.
8602 when Attribute_Count =>
8603 if Nkind (P) = N_Indexed_Component
8604 and then Is_Entity_Name (Prefix (P))
8607 Indx : constant Node_Id := First (Expressions (P));
8608 Fam : constant Entity_Id := Entity (Prefix (P));
8610 Resolve (Indx, Entry_Index_Type (Fam));
8611 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8619 -- Prefix of the Elaborated attribute is a subprogram name which
8620 -- must not be resolved, since this is definitely not a call. Note
8621 -- that it is a library unit, so it cannot be overloaded here.
8623 when Attribute_Elaborated =>
8630 -- Prefix of Enabled attribute is a check name, which must be treated
8631 -- specially and not touched by Resolve.
8633 when Attribute_Enabled =>
8636 --------------------
8637 -- Mechanism_Code --
8638 --------------------
8640 -- Prefix of the Mechanism_Code attribute is a function name
8641 -- which must not be resolved. Should we check for overloaded ???
8643 when Attribute_Mechanism_Code =>
8650 -- Most processing is done in sem_dist, after determining the
8651 -- context type. Node is rewritten as a conversion to a runtime call.
8653 when Attribute_Partition_ID =>
8654 Process_Partition_Id (N);
8661 when Attribute_Pool_Address =>
8668 -- We replace the Range attribute node with a range expression whose
8669 -- bounds are the 'First and 'Last attributes applied to the same
8670 -- prefix. The reason that we do this transformation here instead of
8671 -- in the expander is that it simplifies other parts of the semantic
8672 -- analysis which assume that the Range has been replaced; thus it
8673 -- must be done even when in semantic-only mode (note that the RM
8674 -- specifically mentions this equivalence, we take care that the
8675 -- prefix is only evaluated once).
8677 when Attribute_Range => Range_Attribute :
8683 if not Is_Entity_Name (P)
8684 or else not Is_Type (Entity (P))
8690 Make_Attribute_Reference (Loc,
8692 Duplicate_Subexpr (P, Name_Req => True),
8693 Attribute_Name => Name_Last,
8694 Expressions => Expressions (N));
8697 Make_Attribute_Reference (Loc,
8699 Attribute_Name => Name_First,
8700 Expressions => Expressions (N));
8702 -- If the original was marked as Must_Not_Freeze (see code
8703 -- in Sem_Ch3.Make_Index), then make sure the rewriting
8704 -- does not freeze either.
8706 if Must_Not_Freeze (N) then
8707 Set_Must_Not_Freeze (HB);
8708 Set_Must_Not_Freeze (LB);
8709 Set_Must_Not_Freeze (Prefix (HB));
8710 Set_Must_Not_Freeze (Prefix (LB));
8713 if Raises_Constraint_Error (Prefix (N)) then
8715 -- Preserve Sloc of prefix in the new bounds, so that
8716 -- the posted warning can be removed if we are within
8717 -- unreachable code.
8719 Set_Sloc (LB, Sloc (Prefix (N)));
8720 Set_Sloc (HB, Sloc (Prefix (N)));
8723 Rewrite (N, Make_Range (Loc, LB, HB));
8724 Analyze_And_Resolve (N, Typ);
8726 -- Ensure that the expanded range does not have side effects
8728 Force_Evaluation (LB);
8729 Force_Evaluation (HB);
8731 -- Normally after resolving attribute nodes, Eval_Attribute
8732 -- is called to do any possible static evaluation of the node.
8733 -- However, here since the Range attribute has just been
8734 -- transformed into a range expression it is no longer an
8735 -- attribute node and therefore the call needs to be avoided
8736 -- and is accomplished by simply returning from the procedure.
8739 end Range_Attribute;
8745 -- We will only come here during the prescan of a spec expression
8746 -- containing a Result attribute. In that case the proper Etype has
8747 -- already been set, and nothing more needs to be done here.
8749 when Attribute_Result =>
8756 -- Prefix must not be resolved in this case, since it is not a
8757 -- real entity reference. No action of any kind is require!
8759 when Attribute_UET_Address =>
8762 ----------------------
8763 -- Unchecked_Access --
8764 ----------------------
8766 -- Processing is shared with Access
8768 -------------------------
8769 -- Unrestricted_Access --
8770 -------------------------
8772 -- Processing is shared with Access
8778 -- Apply range check. Note that we did not do this during the
8779 -- analysis phase, since we wanted Eval_Attribute to have a
8780 -- chance at finding an illegal out of range value.
8782 when Attribute_Val =>
8784 -- Note that we do our own Eval_Attribute call here rather than
8785 -- use the common one, because we need to do processing after
8786 -- the call, as per above comment.
8790 -- Eval_Attribute may replace the node with a raise CE, or
8791 -- fold it to a constant. Obviously we only apply a scalar
8792 -- range check if this did not happen!
8794 if Nkind (N) = N_Attribute_Reference
8795 and then Attribute_Name (N) = Name_Val
8797 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
8806 -- Prefix of Version attribute can be a subprogram name which
8807 -- must not be resolved, since this is not a call.
8809 when Attribute_Version =>
8812 ----------------------
8813 -- Other Attributes --
8814 ----------------------
8816 -- For other attributes, resolve prefix unless it is a type. If
8817 -- the attribute reference itself is a type name ('Base and 'Class)
8818 -- then this is only legal within a task or protected record.
8821 if not Is_Entity_Name (P)
8822 or else not Is_Type (Entity (P))
8827 -- If the attribute reference itself is a type name ('Base,
8828 -- 'Class) then this is only legal within a task or protected
8829 -- record. What is this all about ???
8831 if Is_Entity_Name (N)
8832 and then Is_Type (Entity (N))
8834 if Is_Concurrent_Type (Entity (N))
8835 and then In_Open_Scopes (Entity (P))
8840 ("invalid use of subtype name in expression or call", N);
8844 -- For attributes whose argument may be a string, complete
8845 -- resolution of argument now. This avoids premature expansion
8846 -- (and the creation of transient scopes) before the attribute
8847 -- reference is resolved.
8850 when Attribute_Value =>
8851 Resolve (First (Expressions (N)), Standard_String);
8853 when Attribute_Wide_Value =>
8854 Resolve (First (Expressions (N)), Standard_Wide_String);
8856 when Attribute_Wide_Wide_Value =>
8857 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
8859 when others => null;
8862 -- If the prefix of the attribute is a class-wide type then it
8863 -- will be expanded into a dispatching call to a predefined
8864 -- primitive. Therefore we must check for potential violation
8865 -- of such restriction.
8867 if Is_Class_Wide_Type (Etype (P)) then
8868 Check_Restriction (No_Dispatching_Calls, N);
8872 -- Normally the Freezing is done by Resolve but sometimes the Prefix
8873 -- is not resolved, in which case the freezing must be done now.
8875 Freeze_Expression (P);
8877 -- Finally perform static evaluation on the attribute reference
8880 end Resolve_Attribute;
8882 --------------------------------
8883 -- Stream_Attribute_Available --
8884 --------------------------------
8886 function Stream_Attribute_Available
8888 Nam : TSS_Name_Type;
8889 Partial_View : Node_Id := Empty) return Boolean
8891 Etyp : Entity_Id := Typ;
8893 -- Start of processing for Stream_Attribute_Available
8896 -- We need some comments in this body ???
8898 if Has_Stream_Attribute_Definition (Typ, Nam) then
8902 if Is_Class_Wide_Type (Typ) then
8903 return not Is_Limited_Type (Typ)
8904 or else Stream_Attribute_Available (Etype (Typ), Nam);
8907 if Nam = TSS_Stream_Input
8908 and then Is_Abstract_Type (Typ)
8909 and then not Is_Class_Wide_Type (Typ)
8914 if not (Is_Limited_Type (Typ)
8915 or else (Present (Partial_View)
8916 and then Is_Limited_Type (Partial_View)))
8921 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
8923 if Nam = TSS_Stream_Input
8924 and then Ada_Version >= Ada_2005
8925 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
8929 elsif Nam = TSS_Stream_Output
8930 and then Ada_Version >= Ada_2005
8931 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
8936 -- Case of Read and Write: check for attribute definition clause that
8937 -- applies to an ancestor type.
8939 while Etype (Etyp) /= Etyp loop
8940 Etyp := Etype (Etyp);
8942 if Has_Stream_Attribute_Definition (Etyp, Nam) then
8947 if Ada_Version < Ada_2005 then
8949 -- In Ada 95 mode, also consider a non-visible definition
8952 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
8955 and then Stream_Attribute_Available
8956 (Btyp, Nam, Partial_View => Typ);
8961 end Stream_Attribute_Available;