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.
220 -- The legality rule only applies to scalar types, even though the
221 -- current AI mentions all subtypes.
223 procedure Check_Array_Or_Scalar_Type;
224 -- Common procedure used by First, Last, Range attribute to check
225 -- that the prefix is a constrained array or scalar type, or a name
226 -- of an array object, and that an argument appears only if appropriate
227 -- (i.e. only in the array case).
229 procedure Check_Array_Type;
230 -- Common semantic checks for all array attributes. Checks that the
231 -- prefix is a constrained array type or the name of an array object.
232 -- The error message for non-arrays is specialized appropriately.
234 procedure Check_Asm_Attribute;
235 -- Common semantic checks for Asm_Input and Asm_Output attributes
237 procedure Check_Component;
238 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
239 -- Position. Checks prefix is an appropriate selected component.
241 procedure Check_Decimal_Fixed_Point_Type;
242 -- Check that prefix of attribute N is a decimal fixed-point type
244 procedure Check_Dereference;
245 -- If the prefix of attribute is an object of an access type, then
246 -- introduce an explicit dereference, and adjust P_Type accordingly.
248 procedure Check_Discrete_Type;
249 -- Verify that prefix of attribute N is a discrete type
252 -- Check that no attribute arguments are present
254 procedure Check_Either_E0_Or_E1;
255 -- Check that there are zero or one attribute arguments present
258 -- Check that exactly one attribute argument is present
261 -- Check that two attribute arguments are present
263 procedure Check_Enum_Image;
264 -- If the prefix type is an enumeration type, set all its literals
265 -- as referenced, since the image function could possibly end up
266 -- referencing any of the literals indirectly. Same for Enum_Val.
267 -- Set the flag only if the reference is in the main code unit. Same
268 -- restriction when resolving 'Value; otherwise an improperly set
269 -- reference when analyzing an inlined body will lose a proper warning
270 -- on a useless with_clause.
272 procedure Check_Fixed_Point_Type;
273 -- Verify that prefix of attribute N is a fixed type
275 procedure Check_Fixed_Point_Type_0;
276 -- Verify that prefix of attribute N is a fixed type and that
277 -- no attribute expressions are present
279 procedure Check_Floating_Point_Type;
280 -- Verify that prefix of attribute N is a float type
282 procedure Check_Floating_Point_Type_0;
283 -- Verify that prefix of attribute N is a float type and that
284 -- no attribute expressions are present
286 procedure Check_Floating_Point_Type_1;
287 -- Verify that prefix of attribute N is a float type and that
288 -- exactly one attribute expression is present
290 procedure Check_Floating_Point_Type_2;
291 -- Verify that prefix of attribute N is a float type and that
292 -- two attribute expressions are present
294 procedure Legal_Formal_Attribute;
295 -- Common processing for attributes Definite and Has_Discriminants.
296 -- Checks that prefix is generic indefinite formal type.
298 procedure Check_SPARK_Restriction_On_Attribute;
299 -- Issue an error in formal mode because attribute N is allowed
301 procedure Check_Integer_Type;
302 -- Verify that prefix of attribute N is an integer type
304 procedure Check_Modular_Integer_Type;
305 -- Verify that prefix of attribute N is a modular integer type
307 procedure Check_Not_CPP_Type;
308 -- Check that P (the prefix of the attribute) is not an CPP type
309 -- for which no Ada predefined primitive is available.
311 procedure Check_Not_Incomplete_Type;
312 -- Check that P (the prefix of the attribute) is not an incomplete
313 -- type or a private type for which no full view has been given.
315 procedure Check_Object_Reference (P : Node_Id);
316 -- Check that P (the prefix of the attribute) is an object reference
318 procedure Check_Program_Unit;
319 -- Verify that prefix of attribute N is a program unit
321 procedure Check_Real_Type;
322 -- Verify that prefix of attribute N is fixed or float type
324 procedure Check_Scalar_Type;
325 -- Verify that prefix of attribute N is a scalar type
327 procedure Check_Standard_Prefix;
328 -- Verify that prefix of attribute N is package Standard
330 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
331 -- Validity checking for stream attribute. Nam is the TSS name of the
332 -- corresponding possible defined attribute function (e.g. for the
333 -- Read attribute, Nam will be TSS_Stream_Read).
335 procedure Check_PolyORB_Attribute;
336 -- Validity checking for PolyORB/DSA attribute
338 procedure Check_Task_Prefix;
339 -- Verify that prefix of attribute N is a task or task type
341 procedure Check_Type;
342 -- Verify that the prefix of attribute N is a type
344 procedure Check_Unit_Name (Nod : Node_Id);
345 -- Check that Nod is of the form of a library unit name, i.e that
346 -- it is an identifier, or a selected component whose prefix is
347 -- itself of the form of a library unit name. Note that this is
348 -- quite different from Check_Program_Unit, since it only checks
349 -- the syntactic form of the name, not the semantic identity. This
350 -- is because it is used with attributes (Elab_Body, Elab_Spec,
351 -- UET_Address and Elaborated) which can refer to non-visible unit.
353 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
354 pragma No_Return (Error_Attr);
355 procedure Error_Attr;
356 pragma No_Return (Error_Attr);
357 -- Posts error using Error_Msg_N at given node, sets type of attribute
358 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
359 -- semantic processing. The message typically contains a % insertion
360 -- character which is replaced by the attribute name. The call with
361 -- no arguments is used when the caller has already generated the
362 -- required error messages.
364 procedure Error_Attr_P (Msg : String);
365 pragma No_Return (Error_Attr);
366 -- Like Error_Attr, but error is posted at the start of the prefix
368 procedure Standard_Attribute (Val : Int);
369 -- Used to process attributes whose prefix is package Standard which
370 -- yield values of type Universal_Integer. The attribute reference
371 -- node is rewritten with an integer literal of the given value.
373 procedure Unexpected_Argument (En : Node_Id);
374 -- Signal unexpected attribute argument (En is the argument)
376 procedure Validate_Non_Static_Attribute_Function_Call;
377 -- Called when processing an attribute that is a function call to a
378 -- non-static function, i.e. an attribute function that either takes
379 -- non-scalar arguments or returns a non-scalar result. Verifies that
380 -- such a call does not appear in a preelaborable context.
382 ------------------------------
383 -- Analyze_Access_Attribute --
384 ------------------------------
386 procedure Analyze_Access_Attribute is
387 Acc_Type : Entity_Id;
392 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
393 -- Build an access-to-object type whose designated type is DT,
394 -- and whose Ekind is appropriate to the attribute type. The
395 -- type that is constructed is returned as the result.
397 procedure Build_Access_Subprogram_Type (P : Node_Id);
398 -- Build an access to subprogram whose designated type is the type of
399 -- the prefix. If prefix is overloaded, so is the node itself. The
400 -- result is stored in Acc_Type.
402 function OK_Self_Reference return Boolean;
403 -- An access reference whose prefix is a type can legally appear
404 -- within an aggregate, where it is obtained by expansion of
405 -- a defaulted aggregate. The enclosing aggregate that contains
406 -- the self-referenced is flagged so that the self-reference can
407 -- be expanded into a reference to the target object (see exp_aggr).
409 ------------------------------
410 -- Build_Access_Object_Type --
411 ------------------------------
413 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
414 Typ : constant Entity_Id :=
416 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
418 Set_Etype (Typ, Typ);
420 Set_Associated_Node_For_Itype (Typ, N);
421 Set_Directly_Designated_Type (Typ, DT);
423 end Build_Access_Object_Type;
425 ----------------------------------
426 -- Build_Access_Subprogram_Type --
427 ----------------------------------
429 procedure Build_Access_Subprogram_Type (P : Node_Id) is
430 Index : Interp_Index;
433 procedure Check_Local_Access (E : Entity_Id);
434 -- Deal with possible access to local subprogram. If we have such
435 -- an access, we set a flag to kill all tracked values on any call
436 -- because this access value may be passed around, and any called
437 -- code might use it to access a local procedure which clobbers a
438 -- tracked value. If the scope is a loop or block, indicate that
439 -- value tracking is disabled for the enclosing subprogram.
441 function Get_Kind (E : Entity_Id) return Entity_Kind;
442 -- Distinguish between access to regular/protected subprograms
444 ------------------------
445 -- Check_Local_Access --
446 ------------------------
448 procedure Check_Local_Access (E : Entity_Id) is
450 if not Is_Library_Level_Entity (E) then
451 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
452 Set_Suppress_Value_Tracking_On_Call
453 (Nearest_Dynamic_Scope (Current_Scope));
455 end Check_Local_Access;
461 function Get_Kind (E : Entity_Id) return Entity_Kind is
463 if Convention (E) = Convention_Protected then
464 return E_Access_Protected_Subprogram_Type;
466 return E_Access_Subprogram_Type;
470 -- Start of processing for Build_Access_Subprogram_Type
473 -- In the case of an access to subprogram, use the name of the
474 -- subprogram itself as the designated type. Type-checking in
475 -- this case compares the signatures of the designated types.
477 -- Note: This fragment of the tree is temporarily malformed
478 -- because the correct tree requires an E_Subprogram_Type entity
479 -- as the designated type. In most cases this designated type is
480 -- later overridden by the semantics with the type imposed by the
481 -- context during the resolution phase. In the specific case of
482 -- the expression Address!(Prim'Unrestricted_Access), used to
483 -- initialize slots of dispatch tables, this work will be done by
484 -- the expander (see Exp_Aggr).
486 -- The reason to temporarily add this kind of node to the tree
487 -- instead of a proper E_Subprogram_Type itype, is the following:
488 -- in case of errors found in the source file we report better
489 -- error messages. For example, instead of generating the
492 -- "expected access to subprogram with profile
493 -- defined at line X"
495 -- we currently generate:
497 -- "expected access to function Z defined at line X"
499 Set_Etype (N, Any_Type);
501 if not Is_Overloaded (P) then
502 Check_Local_Access (Entity (P));
504 if not Is_Intrinsic_Subprogram (Entity (P)) then
505 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
506 Set_Is_Public (Acc_Type, False);
507 Set_Etype (Acc_Type, Acc_Type);
508 Set_Convention (Acc_Type, Convention (Entity (P)));
509 Set_Directly_Designated_Type (Acc_Type, Entity (P));
510 Set_Etype (N, Acc_Type);
511 Freeze_Before (N, Acc_Type);
515 Get_First_Interp (P, Index, It);
516 while Present (It.Nam) loop
517 Check_Local_Access (It.Nam);
519 if not Is_Intrinsic_Subprogram (It.Nam) then
520 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
521 Set_Is_Public (Acc_Type, False);
522 Set_Etype (Acc_Type, Acc_Type);
523 Set_Convention (Acc_Type, Convention (It.Nam));
524 Set_Directly_Designated_Type (Acc_Type, It.Nam);
525 Add_One_Interp (N, Acc_Type, Acc_Type);
526 Freeze_Before (N, Acc_Type);
529 Get_Next_Interp (Index, It);
533 -- Cannot be applied to intrinsic. Looking at the tests above,
534 -- the only way Etype (N) can still be set to Any_Type is if
535 -- Is_Intrinsic_Subprogram was True for some referenced entity.
537 if Etype (N) = Any_Type then
538 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
540 end Build_Access_Subprogram_Type;
542 ----------------------
543 -- OK_Self_Reference --
544 ----------------------
546 function OK_Self_Reference return Boolean is
553 (Nkind (Par) = N_Component_Association
554 or else Nkind (Par) in N_Subexpr)
556 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
557 if Etype (Par) = Typ then
558 Set_Has_Self_Reference (Par);
566 -- No enclosing aggregate, or not a self-reference
569 end OK_Self_Reference;
571 -- Start of processing for Analyze_Access_Attribute
574 Check_SPARK_Restriction_On_Attribute;
577 if Nkind (P) = N_Character_Literal then
579 ("prefix of % attribute cannot be enumeration literal");
582 -- Case of access to subprogram
584 if Is_Entity_Name (P)
585 and then Is_Overloadable (Entity (P))
587 if Has_Pragma_Inline_Always (Entity (P)) then
589 ("prefix of % attribute cannot be Inline_Always subprogram");
592 if Aname = Name_Unchecked_Access then
593 Error_Attr ("attribute% cannot be applied to a subprogram", P);
596 -- Issue an error if the prefix denotes an eliminated subprogram
598 Check_For_Eliminated_Subprogram (P, Entity (P));
600 -- Check for obsolescent subprogram reference
602 Check_Obsolescent_2005_Entity (Entity (P), P);
604 -- Build the appropriate subprogram type
606 Build_Access_Subprogram_Type (P);
608 -- For P'Access or P'Unrestricted_Access, where P is a nested
609 -- subprogram, we might be passing P to another subprogram (but we
610 -- don't check that here), which might call P. P could modify
611 -- local variables, so we need to kill current values. It is
612 -- important not to do this for library-level subprograms, because
613 -- Kill_Current_Values is very inefficient in the case of library
614 -- level packages with lots of tagged types.
616 if Is_Library_Level_Entity (Entity (Prefix (N))) then
619 -- Do not kill values on nodes initializing dispatch tables
620 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
621 -- is currently generated by the expander only for this
622 -- purpose. Done to keep the quality of warnings currently
623 -- generated by the compiler (otherwise any declaration of
624 -- a tagged type cleans constant indications from its scope).
626 elsif Nkind (Parent (N)) = N_Unchecked_Type_Conversion
627 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
629 Etype (Parent (N)) = RTE (RE_Size_Ptr))
630 and then Is_Dispatching_Operation
631 (Directly_Designated_Type (Etype (N)))
641 -- Component is an operation of a protected type
643 elsif Nkind (P) = N_Selected_Component
644 and then Is_Overloadable (Entity (Selector_Name (P)))
646 if Ekind (Entity (Selector_Name (P))) = E_Entry then
647 Error_Attr_P ("prefix of % attribute must be subprogram");
650 Build_Access_Subprogram_Type (Selector_Name (P));
654 -- Deal with incorrect reference to a type, but note that some
655 -- accesses are allowed: references to the current type instance,
656 -- or in Ada 2005 self-referential pointer in a default-initialized
659 if Is_Entity_Name (P) then
662 -- The reference may appear in an aggregate that has been expanded
663 -- into a loop. Locate scope of type definition, if any.
665 Scop := Current_Scope;
666 while Ekind (Scop) = E_Loop loop
667 Scop := Scope (Scop);
670 if Is_Type (Typ) then
672 -- OK if we are within the scope of a limited type
673 -- let's mark the component as having per object constraint
675 if Is_Anonymous_Tagged_Base (Scop, Typ) then
683 Q : Node_Id := Parent (N);
687 and then Nkind (Q) /= N_Component_Declaration
693 Set_Has_Per_Object_Constraint
694 (Defining_Identifier (Q), True);
698 if Nkind (P) = N_Expanded_Name then
700 ("current instance prefix must be a direct name", P);
703 -- If a current instance attribute appears in a component
704 -- constraint it must appear alone; other contexts (spec-
705 -- expressions, within a task body) are not subject to this
708 if not In_Spec_Expression
709 and then not Has_Completion (Scop)
711 Nkind_In (Parent (N), N_Discriminant_Association,
712 N_Index_Or_Discriminant_Constraint)
715 ("current instance attribute must appear alone", N);
718 if Is_CPP_Class (Root_Type (Typ)) then
720 ("?current instance unsupported for derivations of "
721 & "'C'P'P types", N);
724 -- OK if we are in initialization procedure for the type
725 -- in question, in which case the reference to the type
726 -- is rewritten as a reference to the current object.
728 elsif Ekind (Scop) = E_Procedure
729 and then Is_Init_Proc (Scop)
730 and then Etype (First_Formal (Scop)) = Typ
733 Make_Attribute_Reference (Loc,
734 Prefix => Make_Identifier (Loc, Name_uInit),
735 Attribute_Name => Name_Unrestricted_Access));
739 -- OK if a task type, this test needs sharpening up ???
741 elsif Is_Task_Type (Typ) then
744 -- OK if self-reference in an aggregate in Ada 2005, and
745 -- the reference comes from a copied default expression.
747 -- Note that we check legality of self-reference even if the
748 -- expression comes from source, e.g. when a single component
749 -- association in an aggregate has a box association.
751 elsif Ada_Version >= Ada_2005
752 and then OK_Self_Reference
756 -- OK if reference to current instance of a protected object
758 elsif Is_Protected_Self_Reference (P) then
761 -- Otherwise we have an error case
764 Error_Attr ("% attribute cannot be applied to type", P);
770 -- If we fall through, we have a normal access to object case.
771 -- Unrestricted_Access is legal wherever an allocator would be
772 -- legal, so its Etype is set to E_Allocator. The expected type
773 -- of the other attributes is a general access type, and therefore
774 -- we label them with E_Access_Attribute_Type.
776 if not Is_Overloaded (P) then
777 Acc_Type := Build_Access_Object_Type (P_Type);
778 Set_Etype (N, Acc_Type);
781 Index : Interp_Index;
784 Set_Etype (N, Any_Type);
785 Get_First_Interp (P, Index, It);
786 while Present (It.Typ) loop
787 Acc_Type := Build_Access_Object_Type (It.Typ);
788 Add_One_Interp (N, Acc_Type, Acc_Type);
789 Get_Next_Interp (Index, It);
794 -- Special cases when we can find a prefix that is an entity name
803 if Is_Entity_Name (PP) then
806 -- If we have an access to an object, and the attribute
807 -- comes from source, then set the object as potentially
808 -- source modified. We do this because the resulting access
809 -- pointer can be used to modify the variable, and we might
810 -- not detect this, leading to some junk warnings.
812 Set_Never_Set_In_Source (Ent, False);
814 -- Mark entity as address taken, and kill current values
816 Set_Address_Taken (Ent);
817 Kill_Current_Values (Ent);
820 elsif Nkind_In (PP, N_Selected_Component,
831 -- Check for aliased view unless unrestricted case. We allow a
832 -- nonaliased prefix when within an instance because the prefix may
833 -- have been a tagged formal object, which is defined to be aliased
834 -- even when the actual might not be (other instance cases will have
835 -- been caught in the generic). Similarly, within an inlined body we
836 -- know that the attribute is legal in the original subprogram, and
837 -- therefore legal in the expansion.
839 if Aname /= Name_Unrestricted_Access
840 and then not Is_Aliased_View (P)
841 and then not In_Instance
842 and then not In_Inlined_Body
844 if Restriction_Check_Required (No_Implicit_Aliasing) then
846 ("prefix of % attribute must be explicitly aliased");
849 ("prefix of % attribute must be aliased");
852 end Analyze_Access_Attribute;
854 ---------------------------------
855 -- Bad_Attribute_For_Predicate --
856 ---------------------------------
858 procedure Bad_Attribute_For_Predicate is
860 if Is_Scalar_Type (P_Type)
861 and then Comes_From_Source (N)
863 Error_Msg_Name_1 := Aname;
864 Bad_Predicated_Subtype_Use
865 ("type& has predicates, attribute % not allowed", N, P_Type);
867 end Bad_Attribute_For_Predicate;
869 --------------------------------
870 -- Check_Array_Or_Scalar_Type --
871 --------------------------------
873 procedure Check_Array_Or_Scalar_Type is
877 -- Dimension number for array attributes
880 -- Case of string literal or string literal subtype. These cases
881 -- cannot arise from legal Ada code, but the expander is allowed
882 -- to generate them. They require special handling because string
883 -- literal subtypes do not have standard bounds (the whole idea
884 -- of these subtypes is to avoid having to generate the bounds)
886 if Ekind (P_Type) = E_String_Literal_Subtype then
887 Set_Etype (N, Etype (First_Index (P_Base_Type)));
892 elsif Is_Scalar_Type (P_Type) then
896 Error_Attr ("invalid argument in % attribute", E1);
898 Set_Etype (N, P_Base_Type);
902 -- The following is a special test to allow 'First to apply to
903 -- private scalar types if the attribute comes from generated
904 -- code. This occurs in the case of Normalize_Scalars code.
906 elsif Is_Private_Type (P_Type)
907 and then Present (Full_View (P_Type))
908 and then Is_Scalar_Type (Full_View (P_Type))
909 and then not Comes_From_Source (N)
911 Set_Etype (N, Implementation_Base_Type (P_Type));
913 -- Array types other than string literal subtypes handled above
918 -- We know prefix is an array type, or the name of an array
919 -- object, and that the expression, if present, is static
920 -- and within the range of the dimensions of the type.
922 pragma Assert (Is_Array_Type (P_Type));
923 Index := First_Index (P_Base_Type);
927 -- First dimension assumed
929 Set_Etype (N, Base_Type (Etype (Index)));
932 D := UI_To_Int (Intval (E1));
934 for J in 1 .. D - 1 loop
938 Set_Etype (N, Base_Type (Etype (Index)));
939 Set_Etype (E1, Standard_Integer);
942 end Check_Array_Or_Scalar_Type;
944 ----------------------
945 -- Check_Array_Type --
946 ----------------------
948 procedure Check_Array_Type is
950 -- Dimension number for array attributes
953 -- If the type is a string literal type, then this must be generated
954 -- internally, and no further check is required on its legality.
956 if Ekind (P_Type) = E_String_Literal_Subtype then
959 -- If the type is a composite, it is an illegal aggregate, no point
962 elsif P_Type = Any_Composite then
966 -- Normal case of array type or subtype
968 Check_Either_E0_Or_E1;
971 if Is_Array_Type (P_Type) then
972 if not Is_Constrained (P_Type)
973 and then Is_Entity_Name (P)
974 and then Is_Type (Entity (P))
976 -- Note: we do not call Error_Attr here, since we prefer to
977 -- continue, using the relevant index type of the array,
978 -- even though it is unconstrained. This gives better error
979 -- recovery behavior.
981 Error_Msg_Name_1 := Aname;
983 ("prefix for % attribute must be constrained array", P);
986 D := Number_Dimensions (P_Type);
989 if Is_Private_Type (P_Type) then
990 Error_Attr_P ("prefix for % attribute may not be private type");
992 elsif Is_Access_Type (P_Type)
993 and then Is_Array_Type (Designated_Type (P_Type))
994 and then Is_Entity_Name (P)
995 and then Is_Type (Entity (P))
997 Error_Attr_P ("prefix of % attribute cannot be access type");
999 elsif Attr_Id = Attribute_First
1001 Attr_Id = Attribute_Last
1003 Error_Attr ("invalid prefix for % attribute", P);
1006 Error_Attr_P ("prefix for % attribute must be array");
1010 if Present (E1) then
1011 Resolve (E1, Any_Integer);
1012 Set_Etype (E1, Standard_Integer);
1014 if not Is_Static_Expression (E1)
1015 or else Raises_Constraint_Error (E1)
1017 Flag_Non_Static_Expr
1018 ("expression for dimension must be static!", E1);
1021 elsif UI_To_Int (Expr_Value (E1)) > D
1022 or else UI_To_Int (Expr_Value (E1)) < 1
1024 Error_Attr ("invalid dimension number for array type", E1);
1028 if (Style_Check and Style_Check_Array_Attribute_Index)
1029 and then Comes_From_Source (N)
1031 Style.Check_Array_Attribute_Index (N, E1, D);
1033 end Check_Array_Type;
1035 -------------------------
1036 -- Check_Asm_Attribute --
1037 -------------------------
1039 procedure Check_Asm_Attribute is
1044 -- Check first argument is static string expression
1046 Analyze_And_Resolve (E1, Standard_String);
1048 if Etype (E1) = Any_Type then
1051 elsif not Is_OK_Static_Expression (E1) then
1052 Flag_Non_Static_Expr
1053 ("constraint argument must be static string expression!", E1);
1057 -- Check second argument is right type
1059 Analyze_And_Resolve (E2, Entity (P));
1061 -- Note: that is all we need to do, we don't need to check
1062 -- that it appears in a correct context. The Ada type system
1063 -- will do that for us.
1065 end Check_Asm_Attribute;
1067 ---------------------
1068 -- Check_Component --
1069 ---------------------
1071 procedure Check_Component is
1075 if Nkind (P) /= N_Selected_Component
1077 (Ekind (Entity (Selector_Name (P))) /= E_Component
1079 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1081 Error_Attr_P ("prefix for % attribute must be selected component");
1083 end Check_Component;
1085 ------------------------------------
1086 -- Check_Decimal_Fixed_Point_Type --
1087 ------------------------------------
1089 procedure Check_Decimal_Fixed_Point_Type is
1093 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1094 Error_Attr_P ("prefix of % attribute must be decimal type");
1096 end Check_Decimal_Fixed_Point_Type;
1098 -----------------------
1099 -- Check_Dereference --
1100 -----------------------
1102 procedure Check_Dereference is
1105 -- Case of a subtype mark
1107 if Is_Entity_Name (P)
1108 and then Is_Type (Entity (P))
1113 -- Case of an expression
1117 if Is_Access_Type (P_Type) then
1119 -- If there is an implicit dereference, then we must freeze
1120 -- the designated type of the access type, since the type of
1121 -- the referenced array is this type (see AI95-00106).
1123 -- As done elsewhere, freezing must not happen when pre-analyzing
1124 -- a pre- or postcondition or a default value for an object or
1125 -- for a formal parameter.
1127 if not In_Spec_Expression then
1128 Freeze_Before (N, Designated_Type (P_Type));
1132 Make_Explicit_Dereference (Sloc (P),
1133 Prefix => Relocate_Node (P)));
1135 Analyze_And_Resolve (P);
1136 P_Type := Etype (P);
1138 if P_Type = Any_Type then
1139 raise Bad_Attribute;
1142 P_Base_Type := Base_Type (P_Type);
1144 end Check_Dereference;
1146 -------------------------
1147 -- Check_Discrete_Type --
1148 -------------------------
1150 procedure Check_Discrete_Type is
1154 if not Is_Discrete_Type (P_Type) then
1155 Error_Attr_P ("prefix of % attribute must be discrete type");
1157 end Check_Discrete_Type;
1163 procedure Check_E0 is
1165 if Present (E1) then
1166 Unexpected_Argument (E1);
1174 procedure Check_E1 is
1176 Check_Either_E0_Or_E1;
1180 -- Special-case attributes that are functions and that appear as
1181 -- the prefix of another attribute. Error is posted on parent.
1183 if Nkind (Parent (N)) = N_Attribute_Reference
1184 and then (Attribute_Name (Parent (N)) = Name_Address
1186 Attribute_Name (Parent (N)) = Name_Code_Address
1188 Attribute_Name (Parent (N)) = Name_Access)
1190 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1191 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1192 Set_Etype (Parent (N), Any_Type);
1193 Set_Entity (Parent (N), Any_Type);
1194 raise Bad_Attribute;
1197 Error_Attr ("missing argument for % attribute", N);
1206 procedure Check_E2 is
1209 Error_Attr ("missing arguments for % attribute (2 required)", N);
1211 Error_Attr ("missing argument for % attribute (2 required)", N);
1215 ---------------------------
1216 -- Check_Either_E0_Or_E1 --
1217 ---------------------------
1219 procedure Check_Either_E0_Or_E1 is
1221 if Present (E2) then
1222 Unexpected_Argument (E2);
1224 end Check_Either_E0_Or_E1;
1226 ----------------------
1227 -- Check_Enum_Image --
1228 ----------------------
1230 procedure Check_Enum_Image is
1234 -- When an enumeration type appears in an attribute reference, all
1235 -- literals of the type are marked as referenced. This must only be
1236 -- done if the attribute reference appears in the current source.
1237 -- Otherwise the information on references may differ between a
1238 -- normal compilation and one that performs inlining.
1240 if Is_Enumeration_Type (P_Base_Type)
1241 and then In_Extended_Main_Code_Unit (N)
1243 Lit := First_Literal (P_Base_Type);
1244 while Present (Lit) loop
1245 Set_Referenced (Lit);
1249 end Check_Enum_Image;
1251 ----------------------------
1252 -- Check_Fixed_Point_Type --
1253 ----------------------------
1255 procedure Check_Fixed_Point_Type is
1259 if not Is_Fixed_Point_Type (P_Type) then
1260 Error_Attr_P ("prefix of % attribute must be fixed point type");
1262 end Check_Fixed_Point_Type;
1264 ------------------------------
1265 -- Check_Fixed_Point_Type_0 --
1266 ------------------------------
1268 procedure Check_Fixed_Point_Type_0 is
1270 Check_Fixed_Point_Type;
1272 end Check_Fixed_Point_Type_0;
1274 -------------------------------
1275 -- Check_Floating_Point_Type --
1276 -------------------------------
1278 procedure Check_Floating_Point_Type is
1282 if not Is_Floating_Point_Type (P_Type) then
1283 Error_Attr_P ("prefix of % attribute must be float type");
1285 end Check_Floating_Point_Type;
1287 ---------------------------------
1288 -- Check_Floating_Point_Type_0 --
1289 ---------------------------------
1291 procedure Check_Floating_Point_Type_0 is
1293 Check_Floating_Point_Type;
1295 end Check_Floating_Point_Type_0;
1297 ---------------------------------
1298 -- Check_Floating_Point_Type_1 --
1299 ---------------------------------
1301 procedure Check_Floating_Point_Type_1 is
1303 Check_Floating_Point_Type;
1305 end Check_Floating_Point_Type_1;
1307 ---------------------------------
1308 -- Check_Floating_Point_Type_2 --
1309 ---------------------------------
1311 procedure Check_Floating_Point_Type_2 is
1313 Check_Floating_Point_Type;
1315 end Check_Floating_Point_Type_2;
1317 ------------------------
1318 -- Check_Integer_Type --
1319 ------------------------
1321 procedure Check_Integer_Type is
1325 if not Is_Integer_Type (P_Type) then
1326 Error_Attr_P ("prefix of % attribute must be integer type");
1328 end Check_Integer_Type;
1330 --------------------------------
1331 -- Check_Modular_Integer_Type --
1332 --------------------------------
1334 procedure Check_Modular_Integer_Type is
1338 if not Is_Modular_Integer_Type (P_Type) then
1340 ("prefix of % attribute must be modular integer type");
1342 end Check_Modular_Integer_Type;
1344 ------------------------
1345 -- Check_Not_CPP_Type --
1346 ------------------------
1348 procedure Check_Not_CPP_Type is
1350 if Is_Tagged_Type (Etype (P))
1351 and then Convention (Etype (P)) = Convention_CPP
1352 and then Is_CPP_Class (Root_Type (Etype (P)))
1355 ("invalid use of % attribute with 'C'P'P tagged type");
1357 end Check_Not_CPP_Type;
1359 -------------------------------
1360 -- Check_Not_Incomplete_Type --
1361 -------------------------------
1363 procedure Check_Not_Incomplete_Type is
1368 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1369 -- dereference we have to check wrong uses of incomplete types
1370 -- (other wrong uses are checked at their freezing point).
1372 -- Example 1: Limited-with
1374 -- limited with Pkg;
1376 -- type Acc is access Pkg.T;
1378 -- S : Integer := X.all'Size; -- ERROR
1381 -- Example 2: Tagged incomplete
1383 -- type T is tagged;
1384 -- type Acc is access all T;
1386 -- S : constant Integer := X.all'Size; -- ERROR
1387 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1389 if Ada_Version >= Ada_2005
1390 and then Nkind (P) = N_Explicit_Dereference
1393 while Nkind (E) = N_Explicit_Dereference loop
1399 if From_With_Type (Typ) then
1401 ("prefix of % attribute cannot be an incomplete type");
1404 if Is_Access_Type (Typ) then
1405 Typ := Directly_Designated_Type (Typ);
1408 if Is_Class_Wide_Type (Typ) then
1409 Typ := Root_Type (Typ);
1412 -- A legal use of a shadow entity occurs only when the unit
1413 -- where the non-limited view resides is imported via a regular
1414 -- with clause in the current body. Such references to shadow
1415 -- entities may occur in subprogram formals.
1417 if Is_Incomplete_Type (Typ)
1418 and then From_With_Type (Typ)
1419 and then Present (Non_Limited_View (Typ))
1420 and then Is_Legal_Shadow_Entity_In_Body (Typ)
1422 Typ := Non_Limited_View (Typ);
1425 if Ekind (Typ) = E_Incomplete_Type
1426 and then No (Full_View (Typ))
1429 ("prefix of % attribute cannot be an incomplete type");
1434 if not Is_Entity_Name (P)
1435 or else not Is_Type (Entity (P))
1436 or else In_Spec_Expression
1440 Check_Fully_Declared (P_Type, P);
1442 end Check_Not_Incomplete_Type;
1444 ----------------------------
1445 -- Check_Object_Reference --
1446 ----------------------------
1448 procedure Check_Object_Reference (P : Node_Id) is
1452 -- If we need an object, and we have a prefix that is the name of
1453 -- a function entity, convert it into a function call.
1455 if Is_Entity_Name (P)
1456 and then Ekind (Entity (P)) = E_Function
1458 Rtyp := Etype (Entity (P));
1461 Make_Function_Call (Sloc (P),
1462 Name => Relocate_Node (P)));
1464 Analyze_And_Resolve (P, Rtyp);
1466 -- Otherwise we must have an object reference
1468 elsif not Is_Object_Reference (P) then
1469 Error_Attr_P ("prefix of % attribute must be object");
1471 end Check_Object_Reference;
1473 ----------------------------
1474 -- Check_PolyORB_Attribute --
1475 ----------------------------
1477 procedure Check_PolyORB_Attribute is
1479 Validate_Non_Static_Attribute_Function_Call;
1484 if Get_PCS_Name /= Name_PolyORB_DSA then
1486 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
1488 end Check_PolyORB_Attribute;
1490 ------------------------
1491 -- Check_Program_Unit --
1492 ------------------------
1494 procedure Check_Program_Unit is
1496 if Is_Entity_Name (P) then
1498 K : constant Entity_Kind := Ekind (Entity (P));
1499 T : constant Entity_Id := Etype (Entity (P));
1502 if K in Subprogram_Kind
1503 or else K in Task_Kind
1504 or else K in Protected_Kind
1505 or else K = E_Package
1506 or else K in Generic_Unit_Kind
1507 or else (K = E_Variable
1511 Is_Protected_Type (T)))
1518 Error_Attr_P ("prefix of % attribute must be program unit");
1519 end Check_Program_Unit;
1521 ---------------------
1522 -- Check_Real_Type --
1523 ---------------------
1525 procedure Check_Real_Type is
1529 if not Is_Real_Type (P_Type) then
1530 Error_Attr_P ("prefix of % attribute must be real type");
1532 end Check_Real_Type;
1534 -----------------------
1535 -- Check_Scalar_Type --
1536 -----------------------
1538 procedure Check_Scalar_Type is
1542 if not Is_Scalar_Type (P_Type) then
1543 Error_Attr_P ("prefix of % attribute must be scalar type");
1545 end Check_Scalar_Type;
1547 ------------------------------------------
1548 -- Check_SPARK_Restriction_On_Attribute --
1549 ------------------------------------------
1551 procedure Check_SPARK_Restriction_On_Attribute is
1553 Error_Msg_Name_1 := Aname;
1554 Check_SPARK_Restriction ("attribute % is not allowed", P);
1555 end Check_SPARK_Restriction_On_Attribute;
1557 ---------------------------
1558 -- Check_Standard_Prefix --
1559 ---------------------------
1561 procedure Check_Standard_Prefix is
1565 if Nkind (P) /= N_Identifier
1566 or else Chars (P) /= Name_Standard
1568 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1570 end Check_Standard_Prefix;
1572 ----------------------------
1573 -- Check_Stream_Attribute --
1574 ----------------------------
1576 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1580 In_Shared_Var_Procs : Boolean;
1581 -- True when compiling the body of System.Shared_Storage.
1582 -- Shared_Var_Procs. For this runtime package (always compiled in
1583 -- GNAT mode), we allow stream attributes references for limited
1584 -- types for the case where shared passive objects are implemented
1585 -- using stream attributes, which is the default in GNAT's persistent
1586 -- storage implementation.
1589 Validate_Non_Static_Attribute_Function_Call;
1591 -- With the exception of 'Input, Stream attributes are procedures,
1592 -- and can only appear at the position of procedure calls. We check
1593 -- for this here, before they are rewritten, to give a more precise
1596 if Nam = TSS_Stream_Input then
1599 elsif Is_List_Member (N)
1600 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
1607 ("invalid context for attribute%, which is a procedure", N);
1611 Btyp := Implementation_Base_Type (P_Type);
1613 -- Stream attributes not allowed on limited types unless the
1614 -- attribute reference was generated by the expander (in which
1615 -- case the underlying type will be used, as described in Sinfo),
1616 -- or the attribute was specified explicitly for the type itself
1617 -- or one of its ancestors (taking visibility rules into account if
1618 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
1619 -- (with no visibility restriction).
1622 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
1624 if Present (Gen_Body) then
1625 In_Shared_Var_Procs :=
1626 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
1628 In_Shared_Var_Procs := False;
1632 if (Comes_From_Source (N)
1633 and then not (In_Shared_Var_Procs or In_Instance))
1634 and then not Stream_Attribute_Available (P_Type, Nam)
1635 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
1637 Error_Msg_Name_1 := Aname;
1639 if Is_Limited_Type (P_Type) then
1641 ("limited type& has no% attribute", P, P_Type);
1642 Explain_Limited_Type (P_Type, P);
1645 ("attribute% for type& is not available", P, P_Type);
1649 -- Check restriction violations
1651 -- First check the No_Streams restriction, which prohibits the use
1652 -- of explicit stream attributes in the source program. We do not
1653 -- prevent the occurrence of stream attributes in generated code,
1654 -- for instance those generated implicitly for dispatching purposes.
1656 if Comes_From_Source (N) then
1657 Check_Restriction (No_Streams, P);
1660 -- AI05-0057: if restriction No_Default_Stream_Attributes is active,
1661 -- it is illegal to use a predefined elementary type stream attribute
1662 -- either by itself, or more importantly as part of the attribute
1663 -- subprogram for a composite type.
1665 if Restriction_Active (No_Default_Stream_Attributes) then
1670 if Nam = TSS_Stream_Input
1672 Nam = TSS_Stream_Read
1675 Type_Without_Stream_Operation (P_Type, TSS_Stream_Read);
1678 Type_Without_Stream_Operation (P_Type, TSS_Stream_Write);
1682 Check_Restriction (No_Default_Stream_Attributes, N);
1685 ("missing user-defined Stream Read or Write for type&",
1687 if not Is_Elementary_Type (P_Type) then
1689 ("\which is a component of type&", N, P_Type);
1695 -- Check special case of Exception_Id and Exception_Occurrence which
1696 -- are not allowed for restriction No_Exception_Registration.
1698 if Restriction_Check_Required (No_Exception_Registration)
1699 and then (Is_RTE (P_Type, RE_Exception_Id)
1701 Is_RTE (P_Type, RE_Exception_Occurrence))
1703 Check_Restriction (No_Exception_Registration, P);
1706 -- Here we must check that the first argument is an access type
1707 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1709 Analyze_And_Resolve (E1);
1712 -- Note: the double call to Root_Type here is needed because the
1713 -- root type of a class-wide type is the corresponding type (e.g.
1714 -- X for X'Class, and we really want to go to the root.)
1716 if not Is_Access_Type (Etyp)
1717 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1718 RTE (RE_Root_Stream_Type)
1721 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1724 -- Check that the second argument is of the right type if there is
1725 -- one (the Input attribute has only one argument so this is skipped)
1727 if Present (E2) then
1730 if Nam = TSS_Stream_Read
1731 and then not Is_OK_Variable_For_Out_Formal (E2)
1734 ("second argument of % attribute must be a variable", E2);
1737 Resolve (E2, P_Type);
1741 end Check_Stream_Attribute;
1743 -----------------------
1744 -- Check_Task_Prefix --
1745 -----------------------
1747 procedure Check_Task_Prefix is
1751 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1752 -- task interface class-wide types.
1754 if Is_Task_Type (Etype (P))
1755 or else (Is_Access_Type (Etype (P))
1756 and then Is_Task_Type (Designated_Type (Etype (P))))
1757 or else (Ada_Version >= Ada_2005
1758 and then Ekind (Etype (P)) = E_Class_Wide_Type
1759 and then Is_Interface (Etype (P))
1760 and then Is_Task_Interface (Etype (P)))
1765 if Ada_Version >= Ada_2005 then
1767 ("prefix of % attribute must be a task or a task " &
1768 "interface class-wide object");
1771 Error_Attr_P ("prefix of % attribute must be a task");
1774 end Check_Task_Prefix;
1780 -- The possibilities are an entity name denoting a type, or an
1781 -- attribute reference that denotes a type (Base or Class). If
1782 -- the type is incomplete, replace it with its full view.
1784 procedure Check_Type is
1786 if not Is_Entity_Name (P)
1787 or else not Is_Type (Entity (P))
1789 Error_Attr_P ("prefix of % attribute must be a type");
1791 elsif Is_Protected_Self_Reference (P) then
1793 ("prefix of % attribute denotes current instance "
1794 & "(RM 9.4(21/2))");
1796 elsif Ekind (Entity (P)) = E_Incomplete_Type
1797 and then Present (Full_View (Entity (P)))
1799 P_Type := Full_View (Entity (P));
1800 Set_Entity (P, P_Type);
1804 ---------------------
1805 -- Check_Unit_Name --
1806 ---------------------
1808 procedure Check_Unit_Name (Nod : Node_Id) is
1810 if Nkind (Nod) = N_Identifier then
1813 elsif Nkind_In (Nod, N_Selected_Component, N_Expanded_Name) then
1814 Check_Unit_Name (Prefix (Nod));
1816 if Nkind (Selector_Name (Nod)) = N_Identifier then
1821 Error_Attr ("argument for % attribute must be unit name", P);
1822 end Check_Unit_Name;
1828 procedure Error_Attr is
1830 Set_Etype (N, Any_Type);
1831 Set_Entity (N, Any_Type);
1832 raise Bad_Attribute;
1835 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1837 Error_Msg_Name_1 := Aname;
1838 Error_Msg_N (Msg, Error_Node);
1846 procedure Error_Attr_P (Msg : String) is
1848 Error_Msg_Name_1 := Aname;
1849 Error_Msg_F (Msg, P);
1853 ----------------------------
1854 -- Legal_Formal_Attribute --
1855 ----------------------------
1857 procedure Legal_Formal_Attribute is
1861 if not Is_Entity_Name (P)
1862 or else not Is_Type (Entity (P))
1864 Error_Attr_P ("prefix of % attribute must be generic type");
1866 elsif Is_Generic_Actual_Type (Entity (P))
1868 or else In_Inlined_Body
1872 elsif Is_Generic_Type (Entity (P)) then
1873 if not Is_Indefinite_Subtype (Entity (P)) then
1875 ("prefix of % attribute must be indefinite generic type");
1880 ("prefix of % attribute must be indefinite generic type");
1883 Set_Etype (N, Standard_Boolean);
1884 end Legal_Formal_Attribute;
1886 ------------------------
1887 -- Standard_Attribute --
1888 ------------------------
1890 procedure Standard_Attribute (Val : Int) is
1892 Check_Standard_Prefix;
1893 Rewrite (N, Make_Integer_Literal (Loc, Val));
1895 end Standard_Attribute;
1897 -------------------------
1898 -- Unexpected Argument --
1899 -------------------------
1901 procedure Unexpected_Argument (En : Node_Id) is
1903 Error_Attr ("unexpected argument for % attribute", En);
1904 end Unexpected_Argument;
1906 -------------------------------------------------
1907 -- Validate_Non_Static_Attribute_Function_Call --
1908 -------------------------------------------------
1910 -- This function should be moved to Sem_Dist ???
1912 procedure Validate_Non_Static_Attribute_Function_Call is
1914 if In_Preelaborated_Unit
1915 and then not In_Subprogram_Or_Concurrent_Unit
1917 Flag_Non_Static_Expr
1918 ("non-static function call in preelaborated unit!", N);
1920 end Validate_Non_Static_Attribute_Function_Call;
1922 -- Start of processing for Analyze_Attribute
1925 -- Immediate return if unrecognized attribute (already diagnosed
1926 -- by parser, so there is nothing more that we need to do)
1928 if not Is_Attribute_Name (Aname) then
1929 raise Bad_Attribute;
1932 -- Deal with Ada 83 issues
1934 if Comes_From_Source (N) then
1935 if not Attribute_83 (Attr_Id) then
1936 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1937 Error_Msg_Name_1 := Aname;
1938 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1941 if Attribute_Impl_Def (Attr_Id) then
1942 Check_Restriction (No_Implementation_Attributes, N);
1947 -- Deal with Ada 2005 attributes that are
1949 if Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005 then
1950 Check_Restriction (No_Implementation_Attributes, N);
1953 -- Remote access to subprogram type access attribute reference needs
1954 -- unanalyzed copy for tree transformation. The analyzed copy is used
1955 -- for its semantic information (whether prefix is a remote subprogram
1956 -- name), the unanalyzed copy is used to construct new subtree rooted
1957 -- with N_Aggregate which represents a fat pointer aggregate.
1959 if Aname = Name_Access then
1960 Discard_Node (Copy_Separate_Tree (N));
1963 -- Analyze prefix and exit if error in analysis. If the prefix is an
1964 -- incomplete type, use full view if available. Note that there are
1965 -- some attributes for which we do not analyze the prefix, since the
1966 -- prefix is not a normal name, or else needs special handling.
1968 if Aname /= Name_Elab_Body
1970 Aname /= Name_Elab_Spec
1972 Aname /= Name_Elab_Subp_Body
1974 Aname /= Name_UET_Address
1976 Aname /= Name_Enabled
1981 P_Type := Etype (P);
1983 if Is_Entity_Name (P)
1984 and then Present (Entity (P))
1985 and then Is_Type (Entity (P))
1987 if Ekind (Entity (P)) = E_Incomplete_Type then
1988 P_Type := Get_Full_View (P_Type);
1989 Set_Entity (P, P_Type);
1990 Set_Etype (P, P_Type);
1992 elsif Entity (P) = Current_Scope
1993 and then Is_Record_Type (Entity (P))
1995 -- Use of current instance within the type. Verify that if the
1996 -- attribute appears within a constraint, it yields an access
1997 -- type, other uses are illegal.
2005 and then Nkind (Parent (Par)) /= N_Component_Definition
2007 Par := Parent (Par);
2011 and then Nkind (Par) = N_Subtype_Indication
2013 if Attr_Id /= Attribute_Access
2014 and then Attr_Id /= Attribute_Unchecked_Access
2015 and then Attr_Id /= Attribute_Unrestricted_Access
2018 ("in a constraint the current instance can only"
2019 & " be used with an access attribute", N);
2026 if P_Type = Any_Type then
2027 raise Bad_Attribute;
2030 P_Base_Type := Base_Type (P_Type);
2033 -- Analyze expressions that may be present, exiting if an error occurs
2040 E1 := First (Exprs);
2043 -- Check for missing/bad expression (result of previous error)
2045 if No (E1) or else Etype (E1) = Any_Type then
2046 raise Bad_Attribute;
2051 if Present (E2) then
2054 if Etype (E2) = Any_Type then
2055 raise Bad_Attribute;
2058 if Present (Next (E2)) then
2059 Unexpected_Argument (Next (E2));
2064 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
2065 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
2067 if Ada_Version < Ada_2005
2068 and then Is_Overloaded (P)
2069 and then Aname /= Name_Access
2070 and then Aname /= Name_Address
2071 and then Aname /= Name_Code_Address
2072 and then Aname /= Name_Count
2073 and then Aname /= Name_Result
2074 and then Aname /= Name_Unchecked_Access
2076 Error_Attr ("ambiguous prefix for % attribute", P);
2078 elsif Ada_Version >= Ada_2005
2079 and then Is_Overloaded (P)
2080 and then Aname /= Name_Access
2081 and then Aname /= Name_Address
2082 and then Aname /= Name_Code_Address
2083 and then Aname /= Name_Result
2084 and then Aname /= Name_Unchecked_Access
2086 -- Ada 2005 (AI-345): Since protected and task types have primitive
2087 -- entry wrappers, the attributes Count, Caller and AST_Entry require
2090 if Ada_Version >= Ada_2005
2091 and then (Aname = Name_Count
2092 or else Aname = Name_Caller
2093 or else Aname = Name_AST_Entry)
2096 Count : Natural := 0;
2101 Get_First_Interp (P, I, It);
2102 while Present (It.Nam) loop
2103 if Comes_From_Source (It.Nam) then
2109 Get_Next_Interp (I, It);
2113 Error_Attr ("ambiguous prefix for % attribute", P);
2115 Set_Is_Overloaded (P, False);
2120 Error_Attr ("ambiguous prefix for % attribute", P);
2124 -- In SPARK, attributes of private types are only allowed if the full
2125 -- type declaration is visible.
2127 if Is_Entity_Name (P)
2128 and then Present (Entity (P)) -- needed in some cases
2129 and then Is_Type (Entity (P))
2130 and then Is_Private_Type (P_Type)
2131 and then not In_Open_Scopes (Scope (P_Type))
2132 and then not In_Spec_Expression
2134 Check_SPARK_Restriction ("invisible attribute of type", N);
2137 -- Remaining processing depends on attribute
2141 -- Attributes related to Ada 2012 iterators. Attribute specifications
2142 -- exist for these, but they cannot be queried.
2144 when Attribute_Constant_Indexing |
2145 Attribute_Default_Iterator |
2146 Attribute_Implicit_Dereference |
2147 Attribute_Iterator_Element |
2148 Attribute_Variable_Indexing =>
2149 Error_Msg_N ("illegal attribute", N);
2155 when Attribute_Abort_Signal =>
2156 Check_Standard_Prefix;
2157 Rewrite (N, New_Reference_To (Stand.Abort_Signal, Loc));
2164 when Attribute_Access =>
2165 Analyze_Access_Attribute;
2171 when Attribute_Address =>
2174 -- Check for some junk cases, where we have to allow the address
2175 -- attribute but it does not make much sense, so at least for now
2176 -- just replace with Null_Address.
2178 -- We also do this if the prefix is a reference to the AST_Entry
2179 -- attribute. If expansion is active, the attribute will be
2180 -- replaced by a function call, and address will work fine and
2181 -- get the proper value, but if expansion is not active, then
2182 -- the check here allows proper semantic analysis of the reference.
2184 -- An Address attribute created by expansion is legal even when it
2185 -- applies to other entity-denoting expressions.
2187 if Is_Protected_Self_Reference (P) then
2189 -- Address attribute on a protected object self reference is legal
2193 elsif Is_Entity_Name (P) then
2195 Ent : constant Entity_Id := Entity (P);
2198 if Is_Subprogram (Ent) then
2199 Set_Address_Taken (Ent);
2200 Kill_Current_Values (Ent);
2202 -- An Address attribute is accepted when generated by the
2203 -- compiler for dispatching operation, and an error is
2204 -- issued once the subprogram is frozen (to avoid confusing
2205 -- errors about implicit uses of Address in the dispatch
2206 -- table initialization).
2208 if Has_Pragma_Inline_Always (Entity (P))
2209 and then Comes_From_Source (P)
2212 ("prefix of % attribute cannot be Inline_Always" &
2215 -- It is illegal to apply 'Address to an intrinsic
2216 -- subprogram. This is now formalized in AI05-0095.
2217 -- In an instance, an attempt to obtain 'Address of an
2218 -- intrinsic subprogram (e.g the renaming of a predefined
2219 -- operator that is an actual) raises Program_Error.
2221 elsif Convention (Ent) = Convention_Intrinsic then
2224 Make_Raise_Program_Error (Loc,
2225 Reason => PE_Address_Of_Intrinsic));
2229 ("cannot take Address of intrinsic subprogram", N);
2232 -- Issue an error if prefix denotes an eliminated subprogram
2235 Check_For_Eliminated_Subprogram (P, Ent);
2238 elsif Is_Object (Ent)
2239 or else Ekind (Ent) = E_Label
2241 Set_Address_Taken (Ent);
2243 -- Deal with No_Implicit_Aliasing restriction
2245 if Restriction_Check_Required (No_Implicit_Aliasing) then
2246 if not Is_Aliased_View (P) then
2247 Check_Restriction (No_Implicit_Aliasing, P);
2251 -- If we have an address of an object, and the attribute
2252 -- comes from source, then set the object as potentially
2253 -- source modified. We do this because the resulting address
2254 -- can potentially be used to modify the variable and we
2255 -- might not detect this, leading to some junk warnings.
2257 Set_Never_Set_In_Source (Ent, False);
2259 elsif (Is_Concurrent_Type (Etype (Ent))
2260 and then Etype (Ent) = Base_Type (Ent))
2261 or else Ekind (Ent) = E_Package
2262 or else Is_Generic_Unit (Ent)
2265 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2268 Error_Attr ("invalid prefix for % attribute", P);
2272 elsif Nkind (P) = N_Attribute_Reference
2273 and then Attribute_Name (P) = Name_AST_Entry
2276 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2278 elsif Is_Object_Reference (P) then
2281 elsif Nkind (P) = N_Selected_Component
2282 and then Is_Subprogram (Entity (Selector_Name (P)))
2286 -- What exactly are we allowing here ??? and is this properly
2287 -- documented in the sinfo documentation for this node ???
2289 elsif not Comes_From_Source (N) then
2293 Error_Attr ("invalid prefix for % attribute", P);
2296 Set_Etype (N, RTE (RE_Address));
2302 when Attribute_Address_Size =>
2303 Standard_Attribute (System_Address_Size);
2309 when Attribute_Adjacent =>
2310 Check_Floating_Point_Type_2;
2311 Set_Etype (N, P_Base_Type);
2312 Resolve (E1, P_Base_Type);
2313 Resolve (E2, P_Base_Type);
2319 when Attribute_Aft =>
2320 Check_Fixed_Point_Type_0;
2321 Set_Etype (N, Universal_Integer);
2327 when Attribute_Alignment =>
2329 -- Don't we need more checking here, cf Size ???
2332 Check_Not_Incomplete_Type;
2334 Set_Etype (N, Universal_Integer);
2340 when Attribute_Asm_Input =>
2341 Check_Asm_Attribute;
2343 -- The back-end may need to take the address of E2
2345 if Is_Entity_Name (E2) then
2346 Set_Address_Taken (Entity (E2));
2349 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2355 when Attribute_Asm_Output =>
2356 Check_Asm_Attribute;
2358 if Etype (E2) = Any_Type then
2361 elsif Aname = Name_Asm_Output then
2362 if not Is_Variable (E2) then
2364 ("second argument for Asm_Output is not variable", E2);
2368 Note_Possible_Modification (E2, Sure => True);
2370 -- The back-end may need to take the address of E2
2372 if Is_Entity_Name (E2) then
2373 Set_Address_Taken (Entity (E2));
2376 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2382 when Attribute_AST_Entry => AST_Entry : declare
2388 -- Indicates if entry family index is present. Note the coding
2389 -- here handles the entry family case, but in fact it cannot be
2390 -- executed currently, because pragma AST_Entry does not permit
2391 -- the specification of an entry family.
2393 procedure Bad_AST_Entry;
2394 -- Signal a bad AST_Entry pragma
2396 function OK_Entry (E : Entity_Id) return Boolean;
2397 -- Checks that E is of an appropriate entity kind for an entry
2398 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2399 -- is set True for the entry family case). In the True case,
2400 -- makes sure that Is_AST_Entry is set on the entry.
2406 procedure Bad_AST_Entry is
2408 Error_Attr_P ("prefix for % attribute must be task entry");
2415 function OK_Entry (E : Entity_Id) return Boolean is
2420 Result := (Ekind (E) = E_Entry_Family);
2422 Result := (Ekind (E) = E_Entry);
2426 if not Is_AST_Entry (E) then
2427 Error_Msg_Name_2 := Aname;
2428 Error_Attr ("% attribute requires previous % pragma", P);
2435 -- Start of processing for AST_Entry
2441 -- Deal with entry family case
2443 if Nkind (P) = N_Indexed_Component then
2451 Ptyp := Etype (Pref);
2453 if Ptyp = Any_Type or else Error_Posted (Pref) then
2457 -- If the prefix is a selected component whose prefix is of an
2458 -- access type, then introduce an explicit dereference.
2459 -- ??? Could we reuse Check_Dereference here?
2461 if Nkind (Pref) = N_Selected_Component
2462 and then Is_Access_Type (Ptyp)
2465 Make_Explicit_Dereference (Sloc (Pref),
2466 Relocate_Node (Pref)));
2467 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2470 -- Prefix can be of the form a.b, where a is a task object
2471 -- and b is one of the entries of the corresponding task type.
2473 if Nkind (Pref) = N_Selected_Component
2474 and then OK_Entry (Entity (Selector_Name (Pref)))
2475 and then Is_Object_Reference (Prefix (Pref))
2476 and then Is_Task_Type (Etype (Prefix (Pref)))
2480 -- Otherwise the prefix must be an entry of a containing task,
2481 -- or of a variable of the enclosing task type.
2484 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2485 Ent := Entity (Pref);
2487 if not OK_Entry (Ent)
2488 or else not In_Open_Scopes (Scope (Ent))
2498 Set_Etype (N, RTE (RE_AST_Handler));
2505 -- Note: when the base attribute appears in the context of a subtype
2506 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2507 -- the following circuit.
2509 when Attribute_Base => Base : declare
2517 if Ada_Version >= Ada_95
2518 and then not Is_Scalar_Type (Typ)
2519 and then not Is_Generic_Type (Typ)
2521 Error_Attr_P ("prefix of Base attribute must be scalar type");
2523 elsif Sloc (Typ) = Standard_Location
2524 and then Base_Type (Typ) = Typ
2525 and then Warn_On_Redundant_Constructs
2527 Error_Msg_NE -- CODEFIX
2528 ("?redundant attribute, & is its own base type", N, Typ);
2531 if Nkind (Parent (N)) /= N_Attribute_Reference then
2532 Error_Msg_Name_1 := Aname;
2533 Check_SPARK_Restriction
2534 ("attribute% is only allowed as prefix of another attribute", P);
2537 Set_Etype (N, Base_Type (Entity (P)));
2538 Set_Entity (N, Base_Type (Entity (P)));
2539 Rewrite (N, New_Reference_To (Entity (N), Loc));
2547 when Attribute_Bit => Bit :
2551 if not Is_Object_Reference (P) then
2552 Error_Attr_P ("prefix for % attribute must be object");
2554 -- What about the access object cases ???
2560 Set_Etype (N, Universal_Integer);
2567 when Attribute_Bit_Order => Bit_Order :
2572 if not Is_Record_Type (P_Type) then
2573 Error_Attr_P ("prefix of % attribute must be record type");
2576 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2578 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2581 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2584 Set_Etype (N, RTE (RE_Bit_Order));
2587 -- Reset incorrect indication of staticness
2589 Set_Is_Static_Expression (N, False);
2596 -- Note: in generated code, we can have a Bit_Position attribute
2597 -- applied to a (naked) record component (i.e. the prefix is an
2598 -- identifier that references an E_Component or E_Discriminant
2599 -- entity directly, and this is interpreted as expected by Gigi.
2600 -- The following code will not tolerate such usage, but when the
2601 -- expander creates this special case, it marks it as analyzed
2602 -- immediately and sets an appropriate type.
2604 when Attribute_Bit_Position =>
2605 if Comes_From_Source (N) then
2609 Set_Etype (N, Universal_Integer);
2615 when Attribute_Body_Version =>
2618 Set_Etype (N, RTE (RE_Version_String));
2624 when Attribute_Callable =>
2626 Set_Etype (N, Standard_Boolean);
2633 when Attribute_Caller => Caller : declare
2640 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2643 if not Is_Entry (Ent) then
2644 Error_Attr ("invalid entry name", N);
2648 Error_Attr ("invalid entry name", N);
2652 for J in reverse 0 .. Scope_Stack.Last loop
2653 S := Scope_Stack.Table (J).Entity;
2655 if S = Scope (Ent) then
2656 Error_Attr ("Caller must appear in matching accept or body", N);
2662 Set_Etype (N, RTE (RO_AT_Task_Id));
2669 when Attribute_Ceiling =>
2670 Check_Floating_Point_Type_1;
2671 Set_Etype (N, P_Base_Type);
2672 Resolve (E1, P_Base_Type);
2678 when Attribute_Class =>
2679 Check_Restriction (No_Dispatch, N);
2683 -- Applying Class to untagged incomplete type is obsolescent in Ada
2684 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
2685 -- this flag gets set by Find_Type in this situation.
2687 if Restriction_Check_Required (No_Obsolescent_Features)
2688 and then Ada_Version >= Ada_2005
2689 and then Ekind (P_Type) = E_Incomplete_Type
2692 DN : constant Node_Id := Declaration_Node (P_Type);
2694 if Nkind (DN) = N_Incomplete_Type_Declaration
2695 and then not Tagged_Present (DN)
2697 Check_Restriction (No_Obsolescent_Features, P);
2706 when Attribute_Code_Address =>
2709 if Nkind (P) = N_Attribute_Reference
2710 and then (Attribute_Name (P) = Name_Elab_Body
2712 Attribute_Name (P) = Name_Elab_Spec)
2716 elsif not Is_Entity_Name (P)
2717 or else (Ekind (Entity (P)) /= E_Function
2719 Ekind (Entity (P)) /= E_Procedure)
2721 Error_Attr ("invalid prefix for % attribute", P);
2722 Set_Address_Taken (Entity (P));
2724 -- Issue an error if the prefix denotes an eliminated subprogram
2727 Check_For_Eliminated_Subprogram (P, Entity (P));
2730 Set_Etype (N, RTE (RE_Address));
2732 ----------------------
2733 -- Compiler_Version --
2734 ----------------------
2736 when Attribute_Compiler_Version =>
2738 Check_Standard_Prefix;
2739 Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
2740 Analyze_And_Resolve (N, Standard_String);
2742 --------------------
2743 -- Component_Size --
2744 --------------------
2746 when Attribute_Component_Size =>
2748 Set_Etype (N, Universal_Integer);
2750 -- Note: unlike other array attributes, unconstrained arrays are OK
2752 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2762 when Attribute_Compose =>
2763 Check_Floating_Point_Type_2;
2764 Set_Etype (N, P_Base_Type);
2765 Resolve (E1, P_Base_Type);
2766 Resolve (E2, Any_Integer);
2772 when Attribute_Constrained =>
2774 Set_Etype (N, Standard_Boolean);
2776 -- Case from RM J.4(2) of constrained applied to private type
2778 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2779 Check_Restriction (No_Obsolescent_Features, P);
2781 if Warn_On_Obsolescent_Feature then
2783 ("constrained for private type is an " &
2784 "obsolescent feature (RM J.4)?", N);
2787 -- If we are within an instance, the attribute must be legal
2788 -- because it was valid in the generic unit. Ditto if this is
2789 -- an inlining of a function declared in an instance.
2792 or else In_Inlined_Body
2796 -- For sure OK if we have a real private type itself, but must
2797 -- be completed, cannot apply Constrained to incomplete type.
2799 elsif Is_Private_Type (Entity (P)) then
2801 -- Note: this is one of the Annex J features that does not
2802 -- generate a warning from -gnatwj, since in fact it seems
2803 -- very useful, and is used in the GNAT runtime.
2805 Check_Not_Incomplete_Type;
2809 -- Normal (non-obsolescent case) of application to object of
2810 -- a discriminated type.
2813 Check_Object_Reference (P);
2815 -- If N does not come from source, then we allow the
2816 -- the attribute prefix to be of a private type whose
2817 -- full type has discriminants. This occurs in cases
2818 -- involving expanded calls to stream attributes.
2820 if not Comes_From_Source (N) then
2821 P_Type := Underlying_Type (P_Type);
2824 -- Must have discriminants or be an access type designating
2825 -- a type with discriminants. If it is a classwide type is ???
2826 -- has unknown discriminants.
2828 if Has_Discriminants (P_Type)
2829 or else Has_Unknown_Discriminants (P_Type)
2831 (Is_Access_Type (P_Type)
2832 and then Has_Discriminants (Designated_Type (P_Type)))
2836 -- Also allow an object of a generic type if extensions allowed
2837 -- and allow this for any type at all.
2839 elsif (Is_Generic_Type (P_Type)
2840 or else Is_Generic_Actual_Type (P_Type))
2841 and then Extensions_Allowed
2847 -- Fall through if bad prefix
2850 ("prefix of % attribute must be object of discriminated type");
2856 when Attribute_Copy_Sign =>
2857 Check_Floating_Point_Type_2;
2858 Set_Etype (N, P_Base_Type);
2859 Resolve (E1, P_Base_Type);
2860 Resolve (E2, P_Base_Type);
2866 when Attribute_Count => Count :
2875 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2878 if Ekind (Ent) /= E_Entry then
2879 Error_Attr ("invalid entry name", N);
2882 elsif Nkind (P) = N_Indexed_Component then
2883 if not Is_Entity_Name (Prefix (P))
2884 or else No (Entity (Prefix (P)))
2885 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2887 if Nkind (Prefix (P)) = N_Selected_Component
2888 and then Present (Entity (Selector_Name (Prefix (P))))
2889 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2893 ("attribute % must apply to entry of current task", P);
2896 Error_Attr ("invalid entry family name", P);
2901 Ent := Entity (Prefix (P));
2904 elsif Nkind (P) = N_Selected_Component
2905 and then Present (Entity (Selector_Name (P)))
2906 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2909 ("attribute % must apply to entry of current task", P);
2912 Error_Attr ("invalid entry name", N);
2916 for J in reverse 0 .. Scope_Stack.Last loop
2917 S := Scope_Stack.Table (J).Entity;
2919 if S = Scope (Ent) then
2920 if Nkind (P) = N_Expanded_Name then
2921 Tsk := Entity (Prefix (P));
2923 -- The prefix denotes either the task type, or else a
2924 -- single task whose task type is being analyzed.
2929 or else (not Is_Type (Tsk)
2930 and then Etype (Tsk) = S
2931 and then not (Comes_From_Source (S)))
2936 ("Attribute % must apply to entry of current task", N);
2942 elsif Ekind (Scope (Ent)) in Task_Kind
2944 not Ekind_In (S, E_Loop, E_Block, E_Entry, E_Entry_Family)
2946 Error_Attr ("Attribute % cannot appear in inner unit", N);
2948 elsif Ekind (Scope (Ent)) = E_Protected_Type
2949 and then not Has_Completion (Scope (Ent))
2951 Error_Attr ("attribute % can only be used inside body", N);
2955 if Is_Overloaded (P) then
2957 Index : Interp_Index;
2961 Get_First_Interp (P, Index, It);
2963 while Present (It.Nam) loop
2964 if It.Nam = Ent then
2967 -- Ada 2005 (AI-345): Do not consider primitive entry
2968 -- wrappers generated for task or protected types.
2970 elsif Ada_Version >= Ada_2005
2971 and then not Comes_From_Source (It.Nam)
2976 Error_Attr ("ambiguous entry name", N);
2979 Get_Next_Interp (Index, It);
2984 Set_Etype (N, Universal_Integer);
2987 -----------------------
2988 -- Default_Bit_Order --
2989 -----------------------
2991 when Attribute_Default_Bit_Order => Default_Bit_Order :
2993 Check_Standard_Prefix;
2995 if Bytes_Big_Endian then
2997 Make_Integer_Literal (Loc, False_Value));
3000 Make_Integer_Literal (Loc, True_Value));
3003 Set_Etype (N, Universal_Integer);
3004 Set_Is_Static_Expression (N);
3005 end Default_Bit_Order;
3011 when Attribute_Definite =>
3012 Legal_Formal_Attribute;
3018 when Attribute_Delta =>
3019 Check_Fixed_Point_Type_0;
3020 Set_Etype (N, Universal_Real);
3026 when Attribute_Denorm =>
3027 Check_Floating_Point_Type_0;
3028 Set_Etype (N, Standard_Boolean);
3030 ---------------------
3031 -- Descriptor_Size --
3032 ---------------------
3034 when Attribute_Descriptor_Size =>
3037 if not Is_Entity_Name (P)
3038 or else not Is_Type (Entity (P))
3040 Error_Attr_P ("prefix of attribute % must denote a type");
3043 Set_Etype (N, Universal_Integer);
3049 when Attribute_Digits =>
3053 if not Is_Floating_Point_Type (P_Type)
3054 and then not Is_Decimal_Fixed_Point_Type (P_Type)
3057 ("prefix of % attribute must be float or decimal type");
3060 Set_Etype (N, Universal_Integer);
3066 -- Also handles processing for Elab_Spec and Elab_Subp_Body
3068 when Attribute_Elab_Body |
3069 Attribute_Elab_Spec |
3070 Attribute_Elab_Subp_Body =>
3073 Check_Unit_Name (P);
3074 Set_Etype (N, Standard_Void_Type);
3076 -- We have to manually call the expander in this case to get
3077 -- the necessary expansion (normally attributes that return
3078 -- entities are not expanded).
3086 -- Shares processing with Elab_Body
3092 when Attribute_Elaborated =>
3094 Check_Unit_Name (P);
3095 Set_Etype (N, Standard_Boolean);
3101 when Attribute_Emax =>
3102 Check_Floating_Point_Type_0;
3103 Set_Etype (N, Universal_Integer);
3109 when Attribute_Enabled =>
3110 Check_Either_E0_Or_E1;
3112 if Present (E1) then
3113 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
3114 Error_Msg_N ("entity name expected for Enabled attribute", E1);
3119 if Nkind (P) /= N_Identifier then
3120 Error_Msg_N ("identifier expected (check name)", P);
3121 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
3122 Error_Msg_N ("& is not a recognized check name", P);
3125 Set_Etype (N, Standard_Boolean);
3131 when Attribute_Enum_Rep => Enum_Rep : declare
3133 if Present (E1) then
3135 Check_Discrete_Type;
3136 Resolve (E1, P_Base_Type);
3139 if not Is_Entity_Name (P)
3140 or else (not Is_Object (Entity (P))
3142 Ekind (Entity (P)) /= E_Enumeration_Literal)
3145 ("prefix of % attribute must be " &
3146 "discrete type/object or enum literal");
3150 Set_Etype (N, Universal_Integer);
3157 when Attribute_Enum_Val => Enum_Val : begin
3161 if not Is_Enumeration_Type (P_Type) then
3162 Error_Attr_P ("prefix of % attribute must be enumeration type");
3165 -- If the enumeration type has a standard representation, the effect
3166 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3168 if not Has_Non_Standard_Rep (P_Base_Type) then
3170 Make_Attribute_Reference (Loc,
3171 Prefix => Relocate_Node (Prefix (N)),
3172 Attribute_Name => Name_Val,
3173 Expressions => New_List (Relocate_Node (E1))));
3174 Analyze_And_Resolve (N, P_Base_Type);
3176 -- Non-standard representation case (enumeration with holes)
3180 Resolve (E1, Any_Integer);
3181 Set_Etype (N, P_Base_Type);
3189 when Attribute_Epsilon =>
3190 Check_Floating_Point_Type_0;
3191 Set_Etype (N, Universal_Real);
3197 when Attribute_Exponent =>
3198 Check_Floating_Point_Type_1;
3199 Set_Etype (N, Universal_Integer);
3200 Resolve (E1, P_Base_Type);
3206 when Attribute_External_Tag =>
3210 Set_Etype (N, Standard_String);
3212 if not Is_Tagged_Type (P_Type) then
3213 Error_Attr_P ("prefix of % attribute must be tagged");
3220 when Attribute_Fast_Math =>
3221 Check_Standard_Prefix;
3223 if Opt.Fast_Math then
3224 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
3226 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
3233 when Attribute_First =>
3234 Check_Array_Or_Scalar_Type;
3235 Bad_Attribute_For_Predicate;
3241 when Attribute_First_Bit =>
3243 Set_Etype (N, Universal_Integer);
3249 when Attribute_Fixed_Value =>
3251 Check_Fixed_Point_Type;
3252 Resolve (E1, Any_Integer);
3253 Set_Etype (N, P_Base_Type);
3259 when Attribute_Floor =>
3260 Check_Floating_Point_Type_1;
3261 Set_Etype (N, P_Base_Type);
3262 Resolve (E1, P_Base_Type);
3268 when Attribute_Fore =>
3269 Check_Fixed_Point_Type_0;
3270 Set_Etype (N, Universal_Integer);
3276 when Attribute_Fraction =>
3277 Check_Floating_Point_Type_1;
3278 Set_Etype (N, P_Base_Type);
3279 Resolve (E1, P_Base_Type);
3285 when Attribute_From_Any =>
3287 Check_PolyORB_Attribute;
3288 Set_Etype (N, P_Base_Type);
3290 -----------------------
3291 -- Has_Access_Values --
3292 -----------------------
3294 when Attribute_Has_Access_Values =>
3297 Set_Etype (N, Standard_Boolean);
3299 -----------------------
3300 -- Has_Tagged_Values --
3301 -----------------------
3303 when Attribute_Has_Tagged_Values =>
3306 Set_Etype (N, Standard_Boolean);
3308 -----------------------
3309 -- Has_Discriminants --
3310 -----------------------
3312 when Attribute_Has_Discriminants =>
3313 Legal_Formal_Attribute;
3319 when Attribute_Identity =>
3323 if Etype (P) = Standard_Exception_Type then
3324 Set_Etype (N, RTE (RE_Exception_Id));
3326 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3327 -- task interface class-wide types.
3329 elsif Is_Task_Type (Etype (P))
3330 or else (Is_Access_Type (Etype (P))
3331 and then Is_Task_Type (Designated_Type (Etype (P))))
3332 or else (Ada_Version >= Ada_2005
3333 and then Ekind (Etype (P)) = E_Class_Wide_Type
3334 and then Is_Interface (Etype (P))
3335 and then Is_Task_Interface (Etype (P)))
3338 Set_Etype (N, RTE (RO_AT_Task_Id));
3341 if Ada_Version >= Ada_2005 then
3343 ("prefix of % attribute must be an exception, a " &
3344 "task or a task interface class-wide object");
3347 ("prefix of % attribute must be a task or an exception");
3355 when Attribute_Image => Image :
3357 Check_SPARK_Restriction_On_Attribute;
3359 Set_Etype (N, Standard_String);
3361 if Is_Real_Type (P_Type) then
3362 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3363 Error_Msg_Name_1 := Aname;
3365 ("(Ada 83) % attribute not allowed for real types", N);
3369 if Is_Enumeration_Type (P_Type) then
3370 Check_Restriction (No_Enumeration_Maps, N);
3374 Resolve (E1, P_Base_Type);
3376 Validate_Non_Static_Attribute_Function_Call;
3383 when Attribute_Img => Img :
3386 Set_Etype (N, Standard_String);
3388 if not Is_Scalar_Type (P_Type)
3389 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3392 ("prefix of % attribute must be scalar object name");
3402 when Attribute_Input =>
3404 Check_Stream_Attribute (TSS_Stream_Input);
3405 Set_Etype (N, P_Base_Type);
3411 when Attribute_Integer_Value =>
3414 Resolve (E1, Any_Fixed);
3416 -- Signal an error if argument type is not a specific fixed-point
3417 -- subtype. An error has been signalled already if the argument
3418 -- was not of a fixed-point type.
3420 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3421 Error_Attr ("argument of % must be of a fixed-point type", E1);
3424 Set_Etype (N, P_Base_Type);
3430 when Attribute_Invalid_Value =>
3433 Set_Etype (N, P_Base_Type);
3434 Invalid_Value_Used := True;
3440 when Attribute_Large =>
3443 Set_Etype (N, Universal_Real);
3449 when Attribute_Last =>
3450 Check_Array_Or_Scalar_Type;
3451 Bad_Attribute_For_Predicate;
3457 when Attribute_Last_Bit =>
3459 Set_Etype (N, Universal_Integer);
3465 when Attribute_Leading_Part =>
3466 Check_Floating_Point_Type_2;
3467 Set_Etype (N, P_Base_Type);
3468 Resolve (E1, P_Base_Type);
3469 Resolve (E2, Any_Integer);
3475 when Attribute_Length =>
3477 Set_Etype (N, Universal_Integer);
3483 when Attribute_Machine =>
3484 Check_Floating_Point_Type_1;
3485 Set_Etype (N, P_Base_Type);
3486 Resolve (E1, P_Base_Type);
3492 when Attribute_Machine_Emax =>
3493 Check_Floating_Point_Type_0;
3494 Set_Etype (N, Universal_Integer);
3500 when Attribute_Machine_Emin =>
3501 Check_Floating_Point_Type_0;
3502 Set_Etype (N, Universal_Integer);
3504 ----------------------
3505 -- Machine_Mantissa --
3506 ----------------------
3508 when Attribute_Machine_Mantissa =>
3509 Check_Floating_Point_Type_0;
3510 Set_Etype (N, Universal_Integer);
3512 -----------------------
3513 -- Machine_Overflows --
3514 -----------------------
3516 when Attribute_Machine_Overflows =>
3519 Set_Etype (N, Standard_Boolean);
3525 when Attribute_Machine_Radix =>
3528 Set_Etype (N, Universal_Integer);
3530 ----------------------
3531 -- Machine_Rounding --
3532 ----------------------
3534 when Attribute_Machine_Rounding =>
3535 Check_Floating_Point_Type_1;
3536 Set_Etype (N, P_Base_Type);
3537 Resolve (E1, P_Base_Type);
3539 --------------------
3540 -- Machine_Rounds --
3541 --------------------
3543 when Attribute_Machine_Rounds =>
3546 Set_Etype (N, Standard_Boolean);
3552 when Attribute_Machine_Size =>
3555 Check_Not_Incomplete_Type;
3556 Set_Etype (N, Universal_Integer);
3562 when Attribute_Mantissa =>
3565 Set_Etype (N, Universal_Integer);
3571 when Attribute_Max =>
3574 Resolve (E1, P_Base_Type);
3575 Resolve (E2, P_Base_Type);
3576 Set_Etype (N, P_Base_Type);
3578 ----------------------------------
3579 -- Max_Alignment_For_Allocation --
3580 -- Max_Size_In_Storage_Elements --
3581 ----------------------------------
3583 when Attribute_Max_Alignment_For_Allocation |
3584 Attribute_Max_Size_In_Storage_Elements =>
3587 Check_Not_Incomplete_Type;
3588 Set_Etype (N, Universal_Integer);
3590 -----------------------
3591 -- Maximum_Alignment --
3592 -----------------------
3594 when Attribute_Maximum_Alignment =>
3595 Standard_Attribute (Ttypes.Maximum_Alignment);
3597 --------------------
3598 -- Mechanism_Code --
3599 --------------------
3601 when Attribute_Mechanism_Code =>
3602 if not Is_Entity_Name (P)
3603 or else not Is_Subprogram (Entity (P))
3605 Error_Attr_P ("prefix of % attribute must be subprogram");
3608 Check_Either_E0_Or_E1;
3610 if Present (E1) then
3611 Resolve (E1, Any_Integer);
3612 Set_Etype (E1, Standard_Integer);
3614 if not Is_Static_Expression (E1) then
3615 Flag_Non_Static_Expr
3616 ("expression for parameter number must be static!", E1);
3619 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3620 or else UI_To_Int (Intval (E1)) < 0
3622 Error_Attr ("invalid parameter number for % attribute", E1);
3626 Set_Etype (N, Universal_Integer);
3632 when Attribute_Min =>
3635 Resolve (E1, P_Base_Type);
3636 Resolve (E2, P_Base_Type);
3637 Set_Etype (N, P_Base_Type);
3643 when Attribute_Mod =>
3645 -- Note: this attribute is only allowed in Ada 2005 mode, but
3646 -- we do not need to test that here, since Mod is only recognized
3647 -- as an attribute name in Ada 2005 mode during the parse.
3650 Check_Modular_Integer_Type;
3651 Resolve (E1, Any_Integer);
3652 Set_Etype (N, P_Base_Type);
3658 when Attribute_Model =>
3659 Check_Floating_Point_Type_1;
3660 Set_Etype (N, P_Base_Type);
3661 Resolve (E1, P_Base_Type);
3667 when Attribute_Model_Emin =>
3668 Check_Floating_Point_Type_0;
3669 Set_Etype (N, Universal_Integer);
3675 when Attribute_Model_Epsilon =>
3676 Check_Floating_Point_Type_0;
3677 Set_Etype (N, Universal_Real);
3679 --------------------
3680 -- Model_Mantissa --
3681 --------------------
3683 when Attribute_Model_Mantissa =>
3684 Check_Floating_Point_Type_0;
3685 Set_Etype (N, Universal_Integer);
3691 when Attribute_Model_Small =>
3692 Check_Floating_Point_Type_0;
3693 Set_Etype (N, Universal_Real);
3699 when Attribute_Modulus =>
3701 Check_Modular_Integer_Type;
3702 Set_Etype (N, Universal_Integer);
3704 --------------------
3705 -- Null_Parameter --
3706 --------------------
3708 when Attribute_Null_Parameter => Null_Parameter : declare
3709 Parnt : constant Node_Id := Parent (N);
3710 GParnt : constant Node_Id := Parent (Parnt);
3712 procedure Bad_Null_Parameter (Msg : String);
3713 -- Used if bad Null parameter attribute node is found. Issues
3714 -- given error message, and also sets the type to Any_Type to
3715 -- avoid blowups later on from dealing with a junk node.
3717 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3718 -- Called to check that Proc_Ent is imported subprogram
3720 ------------------------
3721 -- Bad_Null_Parameter --
3722 ------------------------
3724 procedure Bad_Null_Parameter (Msg : String) is
3726 Error_Msg_N (Msg, N);
3727 Set_Etype (N, Any_Type);
3728 end Bad_Null_Parameter;
3730 ----------------------
3731 -- Must_Be_Imported --
3732 ----------------------
3734 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3735 Pent : constant Entity_Id := Ultimate_Alias (Proc_Ent);
3738 -- Ignore check if procedure not frozen yet (we will get
3739 -- another chance when the default parameter is reanalyzed)
3741 if not Is_Frozen (Pent) then
3744 elsif not Is_Imported (Pent) then
3746 ("Null_Parameter can only be used with imported subprogram");
3751 end Must_Be_Imported;
3753 -- Start of processing for Null_Parameter
3758 Set_Etype (N, P_Type);
3760 -- Case of attribute used as default expression
3762 if Nkind (Parnt) = N_Parameter_Specification then
3763 Must_Be_Imported (Defining_Entity (GParnt));
3765 -- Case of attribute used as actual for subprogram (positional)
3767 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3769 and then Is_Entity_Name (Name (Parnt))
3771 Must_Be_Imported (Entity (Name (Parnt)));
3773 -- Case of attribute used as actual for subprogram (named)
3775 elsif Nkind (Parnt) = N_Parameter_Association
3776 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3778 and then Is_Entity_Name (Name (GParnt))
3780 Must_Be_Imported (Entity (Name (GParnt)));
3782 -- Not an allowed case
3786 ("Null_Parameter must be actual or default parameter");
3794 when Attribute_Object_Size =>
3797 Check_Not_Incomplete_Type;
3798 Set_Etype (N, Universal_Integer);
3804 when Attribute_Old =>
3806 -- The attribute reference is a primary. If expressions follow, the
3807 -- attribute reference is an indexable object, so rewrite the node
3810 if Present (E1) then
3812 Make_Indexed_Component (Loc,
3814 Make_Attribute_Reference (Loc,
3815 Prefix => Relocate_Node (Prefix (N)),
3816 Attribute_Name => Name_Old),
3817 Expressions => Expressions (N)));
3825 -- Prefix has not been analyzed yet, and its full analysis will take
3826 -- place during expansion (see below).
3828 Preanalyze_And_Resolve (P);
3829 P_Type := Etype (P);
3830 Set_Etype (N, P_Type);
3832 if No (Current_Subprogram) then
3833 Error_Attr ("attribute % can only appear within subprogram", N);
3836 if Is_Limited_Type (P_Type) then
3837 Error_Attr ("attribute % cannot apply to limited objects", P);
3840 if Is_Entity_Name (P)
3841 and then Is_Constant_Object (Entity (P))
3844 ("?attribute Old applied to constant has no effect", P);
3847 -- Check that the expression does not refer to local entities
3849 Check_Local : declare
3850 Subp : Entity_Id := Current_Subprogram;
3852 function Process (N : Node_Id) return Traverse_Result;
3853 -- Check that N does not contain references to local variables or
3854 -- other local entities of Subp.
3860 function Process (N : Node_Id) return Traverse_Result is
3862 if Is_Entity_Name (N)
3863 and then Present (Entity (N))
3864 and then not Is_Formal (Entity (N))
3865 and then Enclosing_Subprogram (Entity (N)) = Subp
3867 Error_Msg_Node_1 := Entity (N);
3869 ("attribute % cannot refer to local variable&", N);
3875 procedure Check_No_Local is new Traverse_Proc;
3877 -- Start of processing for Check_Local
3882 if In_Parameter_Specification (P) then
3884 -- We have additional restrictions on using 'Old in parameter
3887 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3889 -- Check that there is no reference to the enclosing
3890 -- subprogram local variables. Otherwise, we might end up
3891 -- being called from the enclosing subprogram and thus using
3892 -- 'Old on a local variable which is not defined at entry
3895 Subp := Enclosing_Subprogram (Current_Subprogram);
3899 -- We must prevent default expression of library-level
3900 -- subprogram from using 'Old, as the subprogram may be
3901 -- used in elaboration code for which there is no enclosing
3905 ("attribute % can only appear within subprogram", N);
3910 -- The attribute appears within a pre/postcondition, but refers to
3911 -- an entity in the enclosing subprogram. If it is a component of a
3912 -- formal its expansion might generate actual subtypes that may be
3913 -- referenced in an inner context, and which must be elaborated
3914 -- within the subprogram itself. As a result we create a declaration
3915 -- for it and insert it at the start of the enclosing subprogram
3916 -- This is properly an expansion activity but it has to be performed
3917 -- now to prevent out-of-order issues.
3919 if Nkind (P) = N_Selected_Component
3920 and then Has_Discriminants (Etype (Prefix (P)))
3922 P_Type := Base_Type (P_Type);
3923 Set_Etype (N, P_Type);
3924 Set_Etype (P, P_Type);
3928 ----------------------
3929 -- Overlaps_Storage --
3930 ----------------------
3932 when Attribute_Overlaps_Storage =>
3933 if Ada_Version < Ada_2012 then
3935 ("attribute Overlaps_Storage is an Ada 2012 feature", N);
3937 ("\unit must be compiled with -gnat2012 switch", N);
3941 -- Both arguments must be objects of any type
3943 Analyze_And_Resolve (P);
3944 Analyze_And_Resolve (E1);
3945 Check_Object_Reference (P);
3946 Check_Object_Reference (E1);
3947 Set_Etype (N, Standard_Boolean);
3953 when Attribute_Output =>
3955 Check_Stream_Attribute (TSS_Stream_Output);
3956 Set_Etype (N, Standard_Void_Type);
3957 Resolve (N, Standard_Void_Type);
3963 when Attribute_Partition_ID => Partition_Id :
3967 if P_Type /= Any_Type then
3968 if not Is_Library_Level_Entity (Entity (P)) then
3970 ("prefix of % attribute must be library-level entity");
3972 -- The defining entity of prefix should not be declared inside a
3973 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3975 elsif Is_Entity_Name (P)
3976 and then Is_Pure (Entity (P))
3978 Error_Attr_P ("prefix of% attribute must not be declared pure");
3982 Set_Etype (N, Universal_Integer);
3985 -------------------------
3986 -- Passed_By_Reference --
3987 -------------------------
3989 when Attribute_Passed_By_Reference =>
3992 Set_Etype (N, Standard_Boolean);
3998 when Attribute_Pool_Address =>
4000 Set_Etype (N, RTE (RE_Address));
4006 when Attribute_Pos =>
4007 Check_Discrete_Type;
4010 if Is_Boolean_Type (P_Type) then
4011 Error_Msg_Name_1 := Aname;
4012 Error_Msg_Name_2 := Chars (P_Type);
4013 Check_SPARK_Restriction
4014 ("attribute% is not allowed for type%", P);
4017 Resolve (E1, P_Base_Type);
4018 Set_Etype (N, Universal_Integer);
4024 when Attribute_Position =>
4026 Set_Etype (N, Universal_Integer);
4032 when Attribute_Pred =>
4036 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
4037 Error_Msg_Name_1 := Aname;
4038 Error_Msg_Name_2 := Chars (P_Type);
4039 Check_SPARK_Restriction
4040 ("attribute% is not allowed for type%", P);
4043 Resolve (E1, P_Base_Type);
4044 Set_Etype (N, P_Base_Type);
4046 -- Nothing to do for real type case
4048 if Is_Real_Type (P_Type) then
4051 -- If not modular type, test for overflow check required
4054 if not Is_Modular_Integer_Type (P_Type)
4055 and then not Range_Checks_Suppressed (P_Base_Type)
4057 Enable_Range_Check (E1);
4065 -- Ada 2005 (AI-327): Dynamic ceiling priorities
4067 when Attribute_Priority =>
4068 if Ada_Version < Ada_2005 then
4069 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
4074 -- The prefix must be a protected object (AARM D.5.2 (2/2))
4078 if Is_Protected_Type (Etype (P))
4079 or else (Is_Access_Type (Etype (P))
4080 and then Is_Protected_Type (Designated_Type (Etype (P))))
4082 Resolve (P, Etype (P));
4084 Error_Attr_P ("prefix of % attribute must be a protected object");
4087 Set_Etype (N, Standard_Integer);
4089 -- Must be called from within a protected procedure or entry of the
4090 -- protected object.
4097 while S /= Etype (P)
4098 and then S /= Standard_Standard
4103 if S = Standard_Standard then
4104 Error_Attr ("the attribute % is only allowed inside protected "
4109 Validate_Non_Static_Attribute_Function_Call;
4115 when Attribute_Range =>
4116 Check_Array_Or_Scalar_Type;
4117 Bad_Attribute_For_Predicate;
4119 if Ada_Version = Ada_83
4120 and then Is_Scalar_Type (P_Type)
4121 and then Comes_From_Source (N)
4124 ("(Ada 83) % attribute not allowed for scalar type", P);
4131 when Attribute_Result => Result : declare
4133 -- The enclosing scope, excluding loops for quantified expressions
4136 -- During analysis, CS is the postcondition subprogram and PS the
4137 -- source subprogram to which the postcondition applies. During
4138 -- pre-analysis, CS is the scope of the subprogram declaration.
4141 -- During pre-analysis, Prag is the enclosing pragma node if any
4144 -- Find enclosing scopes, excluding loops
4146 CS := Current_Scope;
4147 while Ekind (CS) = E_Loop loop
4153 -- If the enclosing subprogram is always inlined, the enclosing
4154 -- postcondition will not be propagated to the expanded call.
4156 if not In_Spec_Expression
4157 and then Has_Pragma_Inline_Always (PS)
4158 and then Warn_On_Redundant_Constructs
4161 ("postconditions on inlined functions not enforced?", N);
4164 -- If we are in the scope of a function and in Spec_Expression mode,
4165 -- this is likely the prescan of the postcondition pragma, and we
4166 -- just set the proper type. If there is an error it will be caught
4167 -- when the real Analyze call is done.
4169 if Ekind (CS) = E_Function
4170 and then In_Spec_Expression
4174 if Chars (CS) /= Chars (P) then
4175 Error_Msg_Name_1 := Name_Result;
4178 ("incorrect prefix for % attribute, expected &", P, CS);
4182 -- Check in postcondition of function
4185 while not Nkind_In (Prag, N_Pragma,
4186 N_Function_Specification,
4189 Prag := Parent (Prag);
4192 if Nkind (Prag) /= N_Pragma then
4194 ("% attribute can only appear in postcondition of function",
4197 elsif Get_Pragma_Id (Prag) = Pragma_Test_Case then
4199 Arg_Ens : constant Node_Id :=
4200 Get_Ensures_From_Test_Case_Pragma (Prag);
4205 while Arg /= Prag and Arg /= Arg_Ens loop
4206 Arg := Parent (Arg);
4209 if Arg /= Arg_Ens then
4210 Error_Attr ("% attribute misplaced inside Test_Case", P);
4214 elsif Get_Pragma_Id (Prag) /= Pragma_Postcondition then
4216 ("% attribute can only appear in postcondition of function",
4220 -- The attribute reference is a primary. If expressions follow,
4221 -- the attribute reference is really an indexable object, so
4222 -- rewrite and analyze as an indexed component.
4224 if Present (E1) then
4226 Make_Indexed_Component (Loc,
4228 Make_Attribute_Reference (Loc,
4229 Prefix => Relocate_Node (Prefix (N)),
4230 Attribute_Name => Name_Result),
4231 Expressions => Expressions (N)));
4236 Set_Etype (N, Etype (CS));
4238 -- If several functions with that name are visible,
4239 -- the intended one is the current scope.
4241 if Is_Overloaded (P) then
4243 Set_Is_Overloaded (P, False);
4246 -- Body case, where we must be inside a generated _Postcondition
4247 -- procedure, and the prefix must be on the scope stack, or else
4248 -- the attribute use is definitely misplaced. The condition itself
4249 -- may have generated transient scopes, and is not necessarily the
4253 while Present (CS) and then CS /= Standard_Standard loop
4254 if Chars (CS) = Name_uPostconditions then
4263 if Chars (CS) = Name_uPostconditions
4264 and then Ekind (PS) = E_Function
4268 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
4269 and then Chars (P) = Chars (PS)
4273 -- Within an instance, the prefix designates the local renaming
4274 -- of the original generic.
4276 elsif Is_Entity_Name (P)
4277 and then Ekind (Entity (P)) = E_Function
4278 and then Present (Alias (Entity (P)))
4279 and then Chars (Alias (Entity (P))) = Chars (PS)
4285 ("incorrect prefix for % attribute, expected &", P, PS);
4289 Rewrite (N, Make_Identifier (Sloc (N), Name_uResult));
4290 Analyze_And_Resolve (N, Etype (PS));
4294 ("% attribute can only appear in postcondition of function",
4304 when Attribute_Range_Length =>
4306 Check_Discrete_Type;
4307 Set_Etype (N, Universal_Integer);
4313 when Attribute_Read =>
4315 Check_Stream_Attribute (TSS_Stream_Read);
4316 Set_Etype (N, Standard_Void_Type);
4317 Resolve (N, Standard_Void_Type);
4318 Note_Possible_Modification (E2, Sure => True);
4324 when Attribute_Ref =>
4328 if Nkind (P) /= N_Expanded_Name
4329 or else not Is_RTE (P_Type, RE_Address)
4331 Error_Attr_P ("prefix of % attribute must be System.Address");
4334 Analyze_And_Resolve (E1, Any_Integer);
4335 Set_Etype (N, RTE (RE_Address));
4341 when Attribute_Remainder =>
4342 Check_Floating_Point_Type_2;
4343 Set_Etype (N, P_Base_Type);
4344 Resolve (E1, P_Base_Type);
4345 Resolve (E2, P_Base_Type);
4351 when Attribute_Round =>
4353 Check_Decimal_Fixed_Point_Type;
4354 Set_Etype (N, P_Base_Type);
4356 -- Because the context is universal_real (3.5.10(12)) it is a legal
4357 -- context for a universal fixed expression. This is the only
4358 -- attribute whose functional description involves U_R.
4360 if Etype (E1) = Universal_Fixed then
4362 Conv : constant Node_Id := Make_Type_Conversion (Loc,
4363 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
4364 Expression => Relocate_Node (E1));
4372 Resolve (E1, Any_Real);
4378 when Attribute_Rounding =>
4379 Check_Floating_Point_Type_1;
4380 Set_Etype (N, P_Base_Type);
4381 Resolve (E1, P_Base_Type);
4387 when Attribute_Safe_Emax =>
4388 Check_Floating_Point_Type_0;
4389 Set_Etype (N, Universal_Integer);
4395 when Attribute_Safe_First =>
4396 Check_Floating_Point_Type_0;
4397 Set_Etype (N, Universal_Real);
4403 when Attribute_Safe_Large =>
4406 Set_Etype (N, Universal_Real);
4412 when Attribute_Safe_Last =>
4413 Check_Floating_Point_Type_0;
4414 Set_Etype (N, Universal_Real);
4420 when Attribute_Safe_Small =>
4423 Set_Etype (N, Universal_Real);
4429 when Attribute_Same_Storage =>
4430 if Ada_Version < Ada_2012 then
4432 ("attribute Same_Storage is an Ada 2012 feature", N);
4434 ("\unit must be compiled with -gnat2012 switch", N);
4439 -- The arguments must be objects of any type
4441 Analyze_And_Resolve (P);
4442 Analyze_And_Resolve (E1);
4443 Check_Object_Reference (P);
4444 Check_Object_Reference (E1);
4445 Set_Etype (N, Standard_Boolean);
4451 when Attribute_Scale =>
4453 Check_Decimal_Fixed_Point_Type;
4454 Set_Etype (N, Universal_Integer);
4460 when Attribute_Scaling =>
4461 Check_Floating_Point_Type_2;
4462 Set_Etype (N, P_Base_Type);
4463 Resolve (E1, P_Base_Type);
4469 when Attribute_Signed_Zeros =>
4470 Check_Floating_Point_Type_0;
4471 Set_Etype (N, Standard_Boolean);
4477 when Attribute_Size | Attribute_VADS_Size => Size :
4481 -- If prefix is parameterless function call, rewrite and resolve
4484 if Is_Entity_Name (P)
4485 and then Ekind (Entity (P)) = E_Function
4489 -- Similar processing for a protected function call
4491 elsif Nkind (P) = N_Selected_Component
4492 and then Ekind (Entity (Selector_Name (P))) = E_Function
4497 if Is_Object_Reference (P) then
4498 Check_Object_Reference (P);
4500 elsif Is_Entity_Name (P)
4501 and then (Is_Type (Entity (P))
4502 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4506 elsif Nkind (P) = N_Type_Conversion
4507 and then not Comes_From_Source (P)
4512 Error_Attr_P ("invalid prefix for % attribute");
4515 Check_Not_Incomplete_Type;
4517 Set_Etype (N, Universal_Integer);
4524 when Attribute_Small =>
4527 Set_Etype (N, Universal_Real);
4533 when Attribute_Storage_Pool => Storage_Pool :
4537 if Is_Access_Type (P_Type) then
4538 if Ekind (P_Type) = E_Access_Subprogram_Type then
4540 ("cannot use % attribute for access-to-subprogram type");
4543 -- Set appropriate entity
4545 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4546 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4548 Set_Entity (N, RTE (RE_Global_Pool_Object));
4551 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4553 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4554 -- Storage_Pool since this attribute is not defined for such
4555 -- types (RM E.2.3(22)).
4557 Validate_Remote_Access_To_Class_Wide_Type (N);
4560 Error_Attr_P ("prefix of % attribute must be access type");
4568 when Attribute_Storage_Size => Storage_Size :
4572 if Is_Task_Type (P_Type) then
4573 Set_Etype (N, Universal_Integer);
4575 -- Use with tasks is an obsolescent feature
4577 Check_Restriction (No_Obsolescent_Features, P);
4579 elsif Is_Access_Type (P_Type) then
4580 if Ekind (P_Type) = E_Access_Subprogram_Type then
4582 ("cannot use % attribute for access-to-subprogram type");
4585 if Is_Entity_Name (P)
4586 and then Is_Type (Entity (P))
4589 Set_Etype (N, Universal_Integer);
4591 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4592 -- Storage_Size since this attribute is not defined for
4593 -- such types (RM E.2.3(22)).
4595 Validate_Remote_Access_To_Class_Wide_Type (N);
4597 -- The prefix is allowed to be an implicit dereference
4598 -- of an access value designating a task.
4602 Set_Etype (N, Universal_Integer);
4606 Error_Attr_P ("prefix of % attribute must be access or task type");
4614 when Attribute_Storage_Unit =>
4615 Standard_Attribute (Ttypes.System_Storage_Unit);
4621 when Attribute_Stream_Size =>
4625 if Is_Entity_Name (P)
4626 and then Is_Elementary_Type (Entity (P))
4628 Set_Etype (N, Universal_Integer);
4630 Error_Attr_P ("invalid prefix for % attribute");
4637 when Attribute_Stub_Type =>
4641 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4643 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4646 ("prefix of% attribute must be remote access to classwide");
4653 when Attribute_Succ =>
4657 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
4658 Error_Msg_Name_1 := Aname;
4659 Error_Msg_Name_2 := Chars (P_Type);
4660 Check_SPARK_Restriction
4661 ("attribute% is not allowed for type%", P);
4664 Resolve (E1, P_Base_Type);
4665 Set_Etype (N, P_Base_Type);
4667 -- Nothing to do for real type case
4669 if Is_Real_Type (P_Type) then
4672 -- If not modular type, test for overflow check required
4675 if not Is_Modular_Integer_Type (P_Type)
4676 and then not Range_Checks_Suppressed (P_Base_Type)
4678 Enable_Range_Check (E1);
4682 --------------------------------
4683 -- System_Allocator_Alignment --
4684 --------------------------------
4686 when Attribute_System_Allocator_Alignment =>
4687 Standard_Attribute (Ttypes.System_Allocator_Alignment);
4693 when Attribute_Tag => Tag :
4698 if not Is_Tagged_Type (P_Type) then
4699 Error_Attr_P ("prefix of % attribute must be tagged");
4701 -- Next test does not apply to generated code
4702 -- why not, and what does the illegal reference mean???
4704 elsif Is_Object_Reference (P)
4705 and then not Is_Class_Wide_Type (P_Type)
4706 and then Comes_From_Source (N)
4709 ("% attribute can only be applied to objects " &
4710 "of class - wide type");
4713 -- The prefix cannot be an incomplete type. However, references
4714 -- to 'Tag can be generated when expanding interface conversions,
4715 -- and this is legal.
4717 if Comes_From_Source (N) then
4718 Check_Not_Incomplete_Type;
4721 -- Set appropriate type
4723 Set_Etype (N, RTE (RE_Tag));
4730 when Attribute_Target_Name => Target_Name : declare
4731 TN : constant String := Sdefault.Target_Name.all;
4735 Check_Standard_Prefix;
4739 if TN (TL) = '/' or else TN (TL) = '\' then
4744 Make_String_Literal (Loc,
4745 Strval => TN (TN'First .. TL)));
4746 Analyze_And_Resolve (N, Standard_String);
4753 when Attribute_Terminated =>
4755 Set_Etype (N, Standard_Boolean);
4762 when Attribute_To_Address =>
4766 if Nkind (P) /= N_Identifier
4767 or else Chars (P) /= Name_System
4769 Error_Attr_P ("prefix of % attribute must be System");
4772 Generate_Reference (RTE (RE_Address), P);
4773 Analyze_And_Resolve (E1, Any_Integer);
4774 Set_Etype (N, RTE (RE_Address));
4780 when Attribute_To_Any =>
4782 Check_PolyORB_Attribute;
4783 Set_Etype (N, RTE (RE_Any));
4789 when Attribute_Truncation =>
4790 Check_Floating_Point_Type_1;
4791 Resolve (E1, P_Base_Type);
4792 Set_Etype (N, P_Base_Type);
4798 when Attribute_Type_Class =>
4801 Check_Not_Incomplete_Type;
4802 Set_Etype (N, RTE (RE_Type_Class));
4808 when Attribute_TypeCode =>
4810 Check_PolyORB_Attribute;
4811 Set_Etype (N, RTE (RE_TypeCode));
4817 when Attribute_Type_Key =>
4821 -- This processing belongs in Eval_Attribute ???
4824 function Type_Key return String_Id;
4825 -- A very preliminary implementation. For now, a signature
4826 -- consists of only the type name. This is clearly incomplete
4827 -- (e.g., adding a new field to a record type should change the
4828 -- type's Type_Key attribute).
4834 function Type_Key return String_Id is
4835 Full_Name : constant String_Id :=
4836 Fully_Qualified_Name_String (Entity (P));
4839 -- Copy all characters in Full_Name but the trailing NUL
4842 for J in 1 .. String_Length (Full_Name) - 1 loop
4843 Store_String_Char (Get_String_Char (Full_Name, Int (J)));
4846 Store_String_Chars ("'Type_Key");
4851 Rewrite (N, Make_String_Literal (Loc, Type_Key));
4854 Analyze_And_Resolve (N, Standard_String);
4860 when Attribute_UET_Address =>
4862 Check_Unit_Name (P);
4863 Set_Etype (N, RTE (RE_Address));
4865 -----------------------
4866 -- Unbiased_Rounding --
4867 -----------------------
4869 when Attribute_Unbiased_Rounding =>
4870 Check_Floating_Point_Type_1;
4871 Set_Etype (N, P_Base_Type);
4872 Resolve (E1, P_Base_Type);
4874 ----------------------
4875 -- Unchecked_Access --
4876 ----------------------
4878 when Attribute_Unchecked_Access =>
4879 if Comes_From_Source (N) then
4880 Check_Restriction (No_Unchecked_Access, N);
4883 Analyze_Access_Attribute;
4885 -------------------------
4886 -- Unconstrained_Array --
4887 -------------------------
4889 when Attribute_Unconstrained_Array =>
4892 Check_Not_Incomplete_Type;
4893 Set_Etype (N, Standard_Boolean);
4895 ------------------------------
4896 -- Universal_Literal_String --
4897 ------------------------------
4899 -- This is a GNAT specific attribute whose prefix must be a named
4900 -- number where the expression is either a single numeric literal,
4901 -- or a numeric literal immediately preceded by a minus sign. The
4902 -- result is equivalent to a string literal containing the text of
4903 -- the literal as it appeared in the source program with a possible
4904 -- leading minus sign.
4906 when Attribute_Universal_Literal_String => Universal_Literal_String :
4910 if not Is_Entity_Name (P)
4911 or else Ekind (Entity (P)) not in Named_Kind
4913 Error_Attr_P ("prefix for % attribute must be named number");
4920 Src : Source_Buffer_Ptr;
4923 Expr := Original_Node (Expression (Parent (Entity (P))));
4925 if Nkind (Expr) = N_Op_Minus then
4927 Expr := Original_Node (Right_Opnd (Expr));
4932 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4934 ("named number for % attribute must be simple literal", N);
4937 -- Build string literal corresponding to source literal text
4942 Store_String_Char (Get_Char_Code ('-'));
4946 Src := Source_Text (Get_Source_File_Index (S));
4948 while Src (S) /= ';' and then Src (S) /= ' ' loop
4949 Store_String_Char (Get_Char_Code (Src (S)));
4953 -- Now we rewrite the attribute with the string literal
4956 Make_String_Literal (Loc, End_String));
4960 end Universal_Literal_String;
4962 -------------------------
4963 -- Unrestricted_Access --
4964 -------------------------
4966 -- This is a GNAT specific attribute which is like Access except that
4967 -- all scope checks and checks for aliased views are omitted.
4969 when Attribute_Unrestricted_Access =>
4971 -- If from source, deal with relevant restrictions
4973 if Comes_From_Source (N) then
4974 Check_Restriction (No_Unchecked_Access, N);
4976 if Nkind (P) in N_Has_Entity
4977 and then Present (Entity (P))
4978 and then Is_Object (Entity (P))
4980 Check_Restriction (No_Implicit_Aliasing, N);
4984 if Is_Entity_Name (P) then
4985 Set_Address_Taken (Entity (P));
4988 Analyze_Access_Attribute;
4994 when Attribute_Val => Val : declare
4997 Check_Discrete_Type;
4999 if Is_Boolean_Type (P_Type) then
5000 Error_Msg_Name_1 := Aname;
5001 Error_Msg_Name_2 := Chars (P_Type);
5002 Check_SPARK_Restriction
5003 ("attribute% is not allowed for type%", P);
5006 Resolve (E1, Any_Integer);
5007 Set_Etype (N, P_Base_Type);
5009 -- Note, we need a range check in general, but we wait for the
5010 -- Resolve call to do this, since we want to let Eval_Attribute
5011 -- have a chance to find an static illegality first!
5018 when Attribute_Valid =>
5021 -- Ignore check for object if we have a 'Valid reference generated
5022 -- by the expanded code, since in some cases valid checks can occur
5023 -- on items that are names, but are not objects (e.g. attributes).
5025 if Comes_From_Source (N) then
5026 Check_Object_Reference (P);
5029 if not Is_Scalar_Type (P_Type) then
5030 Error_Attr_P ("object for % attribute must be of scalar type");
5033 Set_Etype (N, Standard_Boolean);
5039 when Attribute_Value => Value :
5041 Check_SPARK_Restriction_On_Attribute;
5045 -- Case of enumeration type
5047 -- When an enumeration type appears in an attribute reference, all
5048 -- literals of the type are marked as referenced. This must only be
5049 -- done if the attribute reference appears in the current source.
5050 -- Otherwise the information on references may differ between a
5051 -- normal compilation and one that performs inlining.
5053 if Is_Enumeration_Type (P_Type)
5054 and then In_Extended_Main_Code_Unit (N)
5056 Check_Restriction (No_Enumeration_Maps, N);
5058 -- Mark all enumeration literals as referenced, since the use of
5059 -- the Value attribute can implicitly reference any of the
5060 -- literals of the enumeration base type.
5063 Ent : Entity_Id := First_Literal (P_Base_Type);
5065 while Present (Ent) loop
5066 Set_Referenced (Ent);
5072 -- Set Etype before resolving expression because expansion of
5073 -- expression may require enclosing type. Note that the type
5074 -- returned by 'Value is the base type of the prefix type.
5076 Set_Etype (N, P_Base_Type);
5077 Validate_Non_Static_Attribute_Function_Call;
5084 when Attribute_Value_Size =>
5087 Check_Not_Incomplete_Type;
5088 Set_Etype (N, Universal_Integer);
5094 when Attribute_Version =>
5097 Set_Etype (N, RTE (RE_Version_String));
5103 when Attribute_Wchar_T_Size =>
5104 Standard_Attribute (Interfaces_Wchar_T_Size);
5110 when Attribute_Wide_Image => Wide_Image :
5112 Check_SPARK_Restriction_On_Attribute;
5114 Set_Etype (N, Standard_Wide_String);
5116 Resolve (E1, P_Base_Type);
5117 Validate_Non_Static_Attribute_Function_Call;
5120 ---------------------
5121 -- Wide_Wide_Image --
5122 ---------------------
5124 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
5127 Set_Etype (N, Standard_Wide_Wide_String);
5129 Resolve (E1, P_Base_Type);
5130 Validate_Non_Static_Attribute_Function_Call;
5131 end Wide_Wide_Image;
5137 when Attribute_Wide_Value => Wide_Value :
5139 Check_SPARK_Restriction_On_Attribute;
5143 -- Set Etype before resolving expression because expansion
5144 -- of expression may require enclosing type.
5146 Set_Etype (N, P_Type);
5147 Validate_Non_Static_Attribute_Function_Call;
5150 ---------------------
5151 -- Wide_Wide_Value --
5152 ---------------------
5154 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
5159 -- Set Etype before resolving expression because expansion
5160 -- of expression may require enclosing type.
5162 Set_Etype (N, P_Type);
5163 Validate_Non_Static_Attribute_Function_Call;
5164 end Wide_Wide_Value;
5166 ---------------------
5167 -- Wide_Wide_Width --
5168 ---------------------
5170 when Attribute_Wide_Wide_Width =>
5173 Set_Etype (N, Universal_Integer);
5179 when Attribute_Wide_Width =>
5180 Check_SPARK_Restriction_On_Attribute;
5183 Set_Etype (N, Universal_Integer);
5189 when Attribute_Width =>
5190 Check_SPARK_Restriction_On_Attribute;
5193 Set_Etype (N, Universal_Integer);
5199 when Attribute_Word_Size =>
5200 Standard_Attribute (System_Word_Size);
5206 when Attribute_Write =>
5208 Check_Stream_Attribute (TSS_Stream_Write);
5209 Set_Etype (N, Standard_Void_Type);
5210 Resolve (N, Standard_Void_Type);
5214 -- All errors raise Bad_Attribute, so that we get out before any further
5215 -- damage occurs when an error is detected (for example, if we check for
5216 -- one attribute expression, and the check succeeds, we want to be able
5217 -- to proceed securely assuming that an expression is in fact present.
5219 -- Note: we set the attribute analyzed in this case to prevent any
5220 -- attempt at reanalysis which could generate spurious error msgs.
5223 when Bad_Attribute =>
5225 Set_Etype (N, Any_Type);
5227 end Analyze_Attribute;
5229 --------------------
5230 -- Eval_Attribute --
5231 --------------------
5233 procedure Eval_Attribute (N : Node_Id) is
5234 Loc : constant Source_Ptr := Sloc (N);
5235 Aname : constant Name_Id := Attribute_Name (N);
5236 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
5237 P : constant Node_Id := Prefix (N);
5239 C_Type : constant Entity_Id := Etype (N);
5240 -- The type imposed by the context
5243 -- First expression, or Empty if none
5246 -- Second expression, or Empty if none
5248 P_Entity : Entity_Id;
5249 -- Entity denoted by prefix
5252 -- The type of the prefix
5254 P_Base_Type : Entity_Id;
5255 -- The base type of the prefix type
5257 P_Root_Type : Entity_Id;
5258 -- The root type of the prefix type
5261 -- True if the result is Static. This is set by the general processing
5262 -- to true if the prefix is static, and all expressions are static. It
5263 -- can be reset as processing continues for particular attributes
5265 Lo_Bound, Hi_Bound : Node_Id;
5266 -- Expressions for low and high bounds of type or array index referenced
5267 -- by First, Last, or Length attribute for array, set by Set_Bounds.
5270 -- Constraint error node used if we have an attribute reference has
5271 -- an argument that raises a constraint error. In this case we replace
5272 -- the attribute with a raise constraint_error node. This is important
5273 -- processing, since otherwise gigi might see an attribute which it is
5274 -- unprepared to deal with.
5276 procedure Check_Concurrent_Discriminant (Bound : Node_Id);
5277 -- If Bound is a reference to a discriminant of a task or protected type
5278 -- occurring within the object's body, rewrite attribute reference into
5279 -- a reference to the corresponding discriminal. Use for the expansion
5280 -- of checks against bounds of entry family index subtypes.
5282 procedure Check_Expressions;
5283 -- In case where the attribute is not foldable, the expressions, if
5284 -- any, of the attribute, are in a non-static context. This procedure
5285 -- performs the required additional checks.
5287 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
5288 -- Determines if the given type has compile time known bounds. Note
5289 -- that we enter the case statement even in cases where the prefix
5290 -- type does NOT have known bounds, so it is important to guard any
5291 -- attempt to evaluate both bounds with a call to this function.
5293 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
5294 -- This procedure is called when the attribute N has a non-static
5295 -- but compile time known value given by Val. It includes the
5296 -- necessary checks for out of range values.
5298 function Fore_Value return Nat;
5299 -- Computes the Fore value for the current attribute prefix, which is
5300 -- known to be a static fixed-point type. Used by Fore and Width.
5302 function Is_VAX_Float (Typ : Entity_Id) return Boolean;
5303 -- Determine whether Typ denotes a VAX floating point type
5305 function Mantissa return Uint;
5306 -- Returns the Mantissa value for the prefix type
5308 procedure Set_Bounds;
5309 -- Used for First, Last and Length attributes applied to an array or
5310 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
5311 -- and high bound expressions for the index referenced by the attribute
5312 -- designator (i.e. the first index if no expression is present, and
5313 -- the N'th index if the value N is present as an expression). Also
5314 -- used for First and Last of scalar types. Static is reset to False
5315 -- if the type or index type is not statically constrained.
5317 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
5318 -- Verify that the prefix of a potentially static array attribute
5319 -- satisfies the conditions of 4.9 (14).
5321 -----------------------------------
5322 -- Check_Concurrent_Discriminant --
5323 -----------------------------------
5325 procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
5327 -- The concurrent (task or protected) type
5330 if Nkind (Bound) = N_Identifier
5331 and then Ekind (Entity (Bound)) = E_Discriminant
5332 and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
5334 Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
5336 if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
5338 -- Find discriminant of original concurrent type, and use
5339 -- its current discriminal, which is the renaming within
5340 -- the task/protected body.
5344 (Find_Body_Discriminal (Entity (Bound)), Loc));
5347 end Check_Concurrent_Discriminant;
5349 -----------------------
5350 -- Check_Expressions --
5351 -----------------------
5353 procedure Check_Expressions is
5357 while Present (E) loop
5358 Check_Non_Static_Context (E);
5361 end Check_Expressions;
5363 ----------------------------------
5364 -- Compile_Time_Known_Attribute --
5365 ----------------------------------
5367 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
5368 T : constant Entity_Id := Etype (N);
5371 Fold_Uint (N, Val, False);
5373 -- Check that result is in bounds of the type if it is static
5375 if Is_In_Range (N, T, Assume_Valid => False) then
5378 elsif Is_Out_Of_Range (N, T) then
5379 Apply_Compile_Time_Constraint_Error
5380 (N, "value not in range of}?", CE_Range_Check_Failed);
5382 elsif not Range_Checks_Suppressed (T) then
5383 Enable_Range_Check (N);
5386 Set_Do_Range_Check (N, False);
5388 end Compile_Time_Known_Attribute;
5390 -------------------------------
5391 -- Compile_Time_Known_Bounds --
5392 -------------------------------
5394 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
5397 Compile_Time_Known_Value (Type_Low_Bound (Typ))
5399 Compile_Time_Known_Value (Type_High_Bound (Typ));
5400 end Compile_Time_Known_Bounds;
5406 -- Note that the Fore calculation is based on the actual values
5407 -- of the bounds, and does not take into account possible rounding.
5409 function Fore_Value return Nat is
5410 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
5411 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
5412 Small : constant Ureal := Small_Value (P_Type);
5413 Lo_Real : constant Ureal := Lo * Small;
5414 Hi_Real : constant Ureal := Hi * Small;
5419 -- Bounds are given in terms of small units, so first compute
5420 -- proper values as reals.
5422 T := UR_Max (abs Lo_Real, abs Hi_Real);
5425 -- Loop to compute proper value if more than one digit required
5427 while T >= Ureal_10 loop
5439 function Is_VAX_Float (Typ : Entity_Id) return Boolean is
5442 Is_Floating_Point_Type (Typ)
5445 or else Float_Rep (Typ) = VAX_Native);
5452 -- Table of mantissa values accessed by function Computed using
5455 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5457 -- where D is T'Digits (RM83 3.5.7)
5459 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5501 function Mantissa return Uint is
5504 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5511 procedure Set_Bounds is
5517 -- For a string literal subtype, we have to construct the bounds.
5518 -- Valid Ada code never applies attributes to string literals, but
5519 -- it is convenient to allow the expander to generate attribute
5520 -- references of this type (e.g. First and Last applied to a string
5523 -- Note that the whole point of the E_String_Literal_Subtype is to
5524 -- avoid this construction of bounds, but the cases in which we
5525 -- have to materialize them are rare enough that we don't worry!
5527 -- The low bound is simply the low bound of the base type. The
5528 -- high bound is computed from the length of the string and this
5531 if Ekind (P_Type) = E_String_Literal_Subtype then
5532 Ityp := Etype (First_Index (Base_Type (P_Type)));
5533 Lo_Bound := Type_Low_Bound (Ityp);
5536 Make_Integer_Literal (Sloc (P),
5538 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5540 Set_Parent (Hi_Bound, P);
5541 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5544 -- For non-array case, just get bounds of scalar type
5546 elsif Is_Scalar_Type (P_Type) then
5549 -- For a fixed-point type, we must freeze to get the attributes
5550 -- of the fixed-point type set now so we can reference them.
5552 if Is_Fixed_Point_Type (P_Type)
5553 and then not Is_Frozen (Base_Type (P_Type))
5554 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5555 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5557 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5560 -- For array case, get type of proper index
5566 Ndim := UI_To_Int (Expr_Value (E1));
5569 Indx := First_Index (P_Type);
5570 for J in 1 .. Ndim - 1 loop
5574 -- If no index type, get out (some other error occurred, and
5575 -- we don't have enough information to complete the job!)
5583 Ityp := Etype (Indx);
5586 -- A discrete range in an index constraint is allowed to be a
5587 -- subtype indication. This is syntactically a pain, but should
5588 -- not propagate to the entity for the corresponding index subtype.
5589 -- After checking that the subtype indication is legal, the range
5590 -- of the subtype indication should be transfered to the entity.
5591 -- The attributes for the bounds should remain the simple retrievals
5592 -- that they are now.
5594 Lo_Bound := Type_Low_Bound (Ityp);
5595 Hi_Bound := Type_High_Bound (Ityp);
5597 if not Is_Static_Subtype (Ityp) then
5602 -------------------------------
5603 -- Statically_Denotes_Entity --
5604 -------------------------------
5606 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5610 if not Is_Entity_Name (N) then
5617 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5618 or else Statically_Denotes_Entity (Renamed_Object (E));
5619 end Statically_Denotes_Entity;
5621 -- Start of processing for Eval_Attribute
5624 -- No folding in spec expression that comes from source where the prefix
5625 -- is an unfrozen entity. This avoids premature folding in cases like:
5627 -- procedure DefExprAnal is
5628 -- type R is new Integer;
5629 -- procedure P (Arg : Integer := R'Size);
5630 -- for R'Size use 64;
5631 -- procedure P (Arg : Integer := R'Size) is
5633 -- Put_Line (Arg'Img);
5639 -- which should print 64 rather than 32. The exclusion of non-source
5640 -- constructs from this test comes from some internal usage in packed
5641 -- arrays, which otherwise fails, could use more analysis perhaps???
5643 -- We do however go ahead with generic actual types, otherwise we get
5644 -- some regressions, probably these types should be frozen anyway???
5646 if In_Spec_Expression
5647 and then Comes_From_Source (N)
5648 and then not (Is_Entity_Name (P)
5650 (Is_Frozen (Entity (P))
5651 or else (Is_Type (Entity (P))
5653 Is_Generic_Actual_Type (Entity (P)))))
5658 -- Acquire first two expressions (at the moment, no attributes take more
5659 -- than two expressions in any case).
5661 if Present (Expressions (N)) then
5662 E1 := First (Expressions (N));
5669 -- Special processing for Enabled attribute. This attribute has a very
5670 -- special prefix, and the easiest way to avoid lots of special checks
5671 -- to protect this special prefix from causing trouble is to deal with
5672 -- this attribute immediately and be done with it.
5674 if Id = Attribute_Enabled then
5676 -- We skip evaluation if the expander is not active. This is not just
5677 -- an optimization. It is of key importance that we not rewrite the
5678 -- attribute in a generic template, since we want to pick up the
5679 -- setting of the check in the instance, and testing expander active
5680 -- is as easy way of doing this as any.
5682 if Expander_Active then
5684 C : constant Check_Id := Get_Check_Id (Chars (P));
5689 if C in Predefined_Check_Id then
5690 R := Scope_Suppress (C);
5692 R := Is_Check_Suppressed (Empty, C);
5696 R := Is_Check_Suppressed (Entity (E1), C);
5700 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5702 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5710 -- Special processing for cases where the prefix is an object. For
5711 -- this purpose, a string literal counts as an object (attributes
5712 -- of string literals can only appear in generated code).
5714 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5716 -- For Component_Size, the prefix is an array object, and we apply
5717 -- the attribute to the type of the object. This is allowed for
5718 -- both unconstrained and constrained arrays, since the bounds
5719 -- have no influence on the value of this attribute.
5721 if Id = Attribute_Component_Size then
5722 P_Entity := Etype (P);
5724 -- For First and Last, the prefix is an array object, and we apply
5725 -- the attribute to the type of the array, but we need a constrained
5726 -- type for this, so we use the actual subtype if available.
5728 elsif Id = Attribute_First
5732 Id = Attribute_Length
5735 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5738 if Present (AS) and then Is_Constrained (AS) then
5741 -- If we have an unconstrained type we cannot fold
5749 -- For Size, give size of object if available, otherwise we
5750 -- cannot fold Size.
5752 elsif Id = Attribute_Size then
5753 if Is_Entity_Name (P)
5754 and then Known_Esize (Entity (P))
5756 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5764 -- For Alignment, give size of object if available, otherwise we
5765 -- cannot fold Alignment.
5767 elsif Id = Attribute_Alignment then
5768 if Is_Entity_Name (P)
5769 and then Known_Alignment (Entity (P))
5771 Fold_Uint (N, Alignment (Entity (P)), False);
5779 -- No other attributes for objects are folded
5786 -- Cases where P is not an object. Cannot do anything if P is
5787 -- not the name of an entity.
5789 elsif not Is_Entity_Name (P) then
5793 -- Otherwise get prefix entity
5796 P_Entity := Entity (P);
5799 -- At this stage P_Entity is the entity to which the attribute
5800 -- is to be applied. This is usually simply the entity of the
5801 -- prefix, except in some cases of attributes for objects, where
5802 -- as described above, we apply the attribute to the object type.
5804 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5805 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5806 -- Note we allow non-static non-generic types at this stage as further
5809 if Is_Type (P_Entity)
5810 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5811 and then (not Is_Generic_Type (P_Entity))
5815 -- Second foldable possibility is an array object (RM 4.9(8))
5817 elsif (Ekind (P_Entity) = E_Variable
5819 Ekind (P_Entity) = E_Constant)
5820 and then Is_Array_Type (Etype (P_Entity))
5821 and then (not Is_Generic_Type (Etype (P_Entity)))
5823 P_Type := Etype (P_Entity);
5825 -- If the entity is an array constant with an unconstrained nominal
5826 -- subtype then get the type from the initial value. If the value has
5827 -- been expanded into assignments, there is no expression and the
5828 -- attribute reference remains dynamic.
5830 -- We could do better here and retrieve the type ???
5832 if Ekind (P_Entity) = E_Constant
5833 and then not Is_Constrained (P_Type)
5835 if No (Constant_Value (P_Entity)) then
5838 P_Type := Etype (Constant_Value (P_Entity));
5842 -- Definite must be folded if the prefix is not a generic type,
5843 -- that is to say if we are within an instantiation. Same processing
5844 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5845 -- Has_Tagged_Value, and Unconstrained_Array.
5847 elsif (Id = Attribute_Definite
5849 Id = Attribute_Has_Access_Values
5851 Id = Attribute_Has_Discriminants
5853 Id = Attribute_Has_Tagged_Values
5855 Id = Attribute_Type_Class
5857 Id = Attribute_Unconstrained_Array
5859 Id = Attribute_Max_Alignment_For_Allocation)
5860 and then not Is_Generic_Type (P_Entity)
5864 -- We can fold 'Size applied to a type if the size is known (as happens
5865 -- for a size from an attribute definition clause). At this stage, this
5866 -- can happen only for types (e.g. record types) for which the size is
5867 -- always non-static. We exclude generic types from consideration (since
5868 -- they have bogus sizes set within templates).
5870 elsif Id = Attribute_Size
5871 and then Is_Type (P_Entity)
5872 and then (not Is_Generic_Type (P_Entity))
5873 and then Known_Static_RM_Size (P_Entity)
5875 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5878 -- We can fold 'Alignment applied to a type if the alignment is known
5879 -- (as happens for an alignment from an attribute definition clause).
5880 -- At this stage, this can happen only for types (e.g. record
5881 -- types) for which the size is always non-static. We exclude
5882 -- generic types from consideration (since they have bogus
5883 -- sizes set within templates).
5885 elsif Id = Attribute_Alignment
5886 and then Is_Type (P_Entity)
5887 and then (not Is_Generic_Type (P_Entity))
5888 and then Known_Alignment (P_Entity)
5890 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5893 -- If this is an access attribute that is known to fail accessibility
5894 -- check, rewrite accordingly.
5896 elsif Attribute_Name (N) = Name_Access
5897 and then Raises_Constraint_Error (N)
5900 Make_Raise_Program_Error (Loc,
5901 Reason => PE_Accessibility_Check_Failed));
5902 Set_Etype (N, C_Type);
5905 -- No other cases are foldable (they certainly aren't static, and at
5906 -- the moment we don't try to fold any cases other than these three).
5913 -- If either attribute or the prefix is Any_Type, then propagate
5914 -- Any_Type to the result and don't do anything else at all.
5916 if P_Type = Any_Type
5917 or else (Present (E1) and then Etype (E1) = Any_Type)
5918 or else (Present (E2) and then Etype (E2) = Any_Type)
5920 Set_Etype (N, Any_Type);
5924 -- Scalar subtype case. We have not yet enforced the static requirement
5925 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5926 -- of non-static attribute references (e.g. S'Digits for a non-static
5927 -- floating-point type, which we can compute at compile time).
5929 -- Note: this folding of non-static attributes is not simply a case of
5930 -- optimization. For many of the attributes affected, Gigi cannot handle
5931 -- the attribute and depends on the front end having folded them away.
5933 -- Note: although we don't require staticness at this stage, we do set
5934 -- the Static variable to record the staticness, for easy reference by
5935 -- those attributes where it matters (e.g. Succ and Pred), and also to
5936 -- be used to ensure that non-static folded things are not marked as
5937 -- being static (a check that is done right at the end).
5939 P_Root_Type := Root_Type (P_Type);
5940 P_Base_Type := Base_Type (P_Type);
5942 -- If the root type or base type is generic, then we cannot fold. This
5943 -- test is needed because subtypes of generic types are not always
5944 -- marked as being generic themselves (which seems odd???)
5946 if Is_Generic_Type (P_Root_Type)
5947 or else Is_Generic_Type (P_Base_Type)
5952 if Is_Scalar_Type (P_Type) then
5953 Static := Is_OK_Static_Subtype (P_Type);
5955 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5956 -- since we can't do anything with unconstrained arrays. In addition,
5957 -- only the First, Last and Length attributes are possibly static.
5959 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5960 -- Type_Class, and Unconstrained_Array are again exceptions, because
5961 -- they apply as well to unconstrained types.
5963 -- In addition Component_Size is an exception since it is possibly
5964 -- foldable, even though it is never static, and it does apply to
5965 -- unconstrained arrays. Furthermore, it is essential to fold this
5966 -- in the packed case, since otherwise the value will be incorrect.
5968 elsif Id = Attribute_Definite
5970 Id = Attribute_Has_Access_Values
5972 Id = Attribute_Has_Discriminants
5974 Id = Attribute_Has_Tagged_Values
5976 Id = Attribute_Type_Class
5978 Id = Attribute_Unconstrained_Array
5980 Id = Attribute_Component_Size
5984 elsif Id /= Attribute_Max_Alignment_For_Allocation then
5985 if not Is_Constrained (P_Type)
5986 or else (Id /= Attribute_First and then
5987 Id /= Attribute_Last and then
5988 Id /= Attribute_Length)
5994 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5995 -- scalar case, we hold off on enforcing staticness, since there are
5996 -- cases which we can fold at compile time even though they are not
5997 -- static (e.g. 'Length applied to a static index, even though other
5998 -- non-static indexes make the array type non-static). This is only
5999 -- an optimization, but it falls out essentially free, so why not.
6000 -- Again we compute the variable Static for easy reference later
6001 -- (note that no array attributes are static in Ada 83).
6003 -- We also need to set Static properly for subsequent legality checks
6004 -- which might otherwise accept non-static constants in contexts
6005 -- where they are not legal.
6007 Static := Ada_Version >= Ada_95
6008 and then Statically_Denotes_Entity (P);
6014 N := First_Index (P_Type);
6016 -- The expression is static if the array type is constrained
6017 -- by given bounds, and not by an initial expression. Constant
6018 -- strings are static in any case.
6020 if Root_Type (P_Type) /= Standard_String then
6022 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
6025 while Present (N) loop
6026 Static := Static and then Is_Static_Subtype (Etype (N));
6028 -- If however the index type is generic, or derived from
6029 -- one, attributes cannot be folded.
6031 if Is_Generic_Type (Root_Type (Etype (N)))
6032 and then Id /= Attribute_Component_Size
6042 -- Check any expressions that are present. Note that these expressions,
6043 -- depending on the particular attribute type, are either part of the
6044 -- attribute designator, or they are arguments in a case where the
6045 -- attribute reference returns a function. In the latter case, the
6046 -- rule in (RM 4.9(22)) applies and in particular requires the type
6047 -- of the expressions to be scalar in order for the attribute to be
6048 -- considered to be static.
6055 while Present (E) loop
6057 -- If expression is not static, then the attribute reference
6058 -- result certainly cannot be static.
6060 if not Is_Static_Expression (E) then
6064 -- If the result is not known at compile time, or is not of
6065 -- a scalar type, then the result is definitely not static,
6066 -- so we can quit now.
6068 if not Compile_Time_Known_Value (E)
6069 or else not Is_Scalar_Type (Etype (E))
6071 -- An odd special case, if this is a Pos attribute, this
6072 -- is where we need to apply a range check since it does
6073 -- not get done anywhere else.
6075 if Id = Attribute_Pos then
6076 if Is_Integer_Type (Etype (E)) then
6077 Apply_Range_Check (E, Etype (N));
6084 -- If the expression raises a constraint error, then so does
6085 -- the attribute reference. We keep going in this case because
6086 -- we are still interested in whether the attribute reference
6087 -- is static even if it is not static.
6089 elsif Raises_Constraint_Error (E) then
6090 Set_Raises_Constraint_Error (N);
6096 if Raises_Constraint_Error (Prefix (N)) then
6101 -- Deal with the case of a static attribute reference that raises
6102 -- constraint error. The Raises_Constraint_Error flag will already
6103 -- have been set, and the Static flag shows whether the attribute
6104 -- reference is static. In any case we certainly can't fold such an
6105 -- attribute reference.
6107 -- Note that the rewriting of the attribute node with the constraint
6108 -- error node is essential in this case, because otherwise Gigi might
6109 -- blow up on one of the attributes it never expects to see.
6111 -- The constraint_error node must have the type imposed by the context,
6112 -- to avoid spurious errors in the enclosing expression.
6114 if Raises_Constraint_Error (N) then
6116 Make_Raise_Constraint_Error (Sloc (N),
6117 Reason => CE_Range_Check_Failed);
6118 Set_Etype (CE_Node, Etype (N));
6119 Set_Raises_Constraint_Error (CE_Node);
6121 Rewrite (N, Relocate_Node (CE_Node));
6122 Set_Is_Static_Expression (N, Static);
6126 -- At this point we have a potentially foldable attribute reference.
6127 -- If Static is set, then the attribute reference definitely obeys
6128 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
6129 -- folded. If Static is not set, then the attribute may or may not
6130 -- be foldable, and the individual attribute processing routines
6131 -- test Static as required in cases where it makes a difference.
6133 -- In the case where Static is not set, we do know that all the
6134 -- expressions present are at least known at compile time (we assumed
6135 -- above that if this was not the case, then there was no hope of static
6136 -- evaluation). However, we did not require that the bounds of the
6137 -- prefix type be compile time known, let alone static). That's because
6138 -- there are many attributes that can be computed at compile time on
6139 -- non-static subtypes, even though such references are not static
6144 -- Attributes related to Ada 2012 iterators (placeholder ???)
6146 when Attribute_Constant_Indexing => null;
6147 when Attribute_Default_Iterator => null;
6148 when Attribute_Implicit_Dereference => null;
6149 when Attribute_Iterator_Element => null;
6150 when Attribute_Variable_Indexing => null;
6156 when Attribute_Adjacent =>
6159 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6165 when Attribute_Aft =>
6166 Fold_Uint (N, Aft_Value (P_Type), True);
6172 when Attribute_Alignment => Alignment_Block : declare
6173 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6176 -- Fold if alignment is set and not otherwise
6178 if Known_Alignment (P_TypeA) then
6179 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
6181 end Alignment_Block;
6187 -- Can only be folded in No_Ast_Handler case
6189 when Attribute_AST_Entry =>
6190 if not Is_AST_Entry (P_Entity) then
6192 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
6201 -- Bit can never be folded
6203 when Attribute_Bit =>
6210 -- Body_version can never be static
6212 when Attribute_Body_Version =>
6219 when Attribute_Ceiling =>
6221 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
6223 --------------------
6224 -- Component_Size --
6225 --------------------
6227 when Attribute_Component_Size =>
6228 if Known_Static_Component_Size (P_Type) then
6229 Fold_Uint (N, Component_Size (P_Type), False);
6236 when Attribute_Compose =>
6239 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
6246 -- Constrained is never folded for now, there may be cases that
6247 -- could be handled at compile time. To be looked at later.
6249 when Attribute_Constrained =>
6256 when Attribute_Copy_Sign =>
6259 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6265 when Attribute_Definite =>
6266 Rewrite (N, New_Occurrence_Of (
6267 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
6268 Analyze_And_Resolve (N, Standard_Boolean);
6274 when Attribute_Delta =>
6275 Fold_Ureal (N, Delta_Value (P_Type), True);
6281 when Attribute_Denorm =>
6283 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
6285 ---------------------
6286 -- Descriptor_Size --
6287 ---------------------
6289 when Attribute_Descriptor_Size =>
6296 when Attribute_Digits =>
6297 Fold_Uint (N, Digits_Value (P_Type), True);
6303 when Attribute_Emax =>
6305 -- Ada 83 attribute is defined as (RM83 3.5.8)
6307 -- T'Emax = 4 * T'Mantissa
6309 Fold_Uint (N, 4 * Mantissa, True);
6315 when Attribute_Enum_Rep =>
6317 -- For an enumeration type with a non-standard representation use
6318 -- the Enumeration_Rep field of the proper constant. Note that this
6319 -- will not work for types Character/Wide_[Wide-]Character, since no
6320 -- real entities are created for the enumeration literals, but that
6321 -- does not matter since these two types do not have non-standard
6322 -- representations anyway.
6324 if Is_Enumeration_Type (P_Type)
6325 and then Has_Non_Standard_Rep (P_Type)
6327 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
6329 -- For enumeration types with standard representations and all
6330 -- other cases (i.e. all integer and modular types), Enum_Rep
6331 -- is equivalent to Pos.
6334 Fold_Uint (N, Expr_Value (E1), Static);
6341 when Attribute_Enum_Val => Enum_Val : declare
6345 -- We have something like Enum_Type'Enum_Val (23), so search for a
6346 -- corresponding value in the list of Enum_Rep values for the type.
6348 Lit := First_Literal (P_Base_Type);
6350 if Enumeration_Rep (Lit) = Expr_Value (E1) then
6351 Fold_Uint (N, Enumeration_Pos (Lit), Static);
6358 Apply_Compile_Time_Constraint_Error
6359 (N, "no representation value matches",
6360 CE_Range_Check_Failed,
6361 Warn => not Static);
6371 when Attribute_Epsilon =>
6373 -- Ada 83 attribute is defined as (RM83 3.5.8)
6375 -- T'Epsilon = 2.0**(1 - T'Mantissa)
6377 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
6383 when Attribute_Exponent =>
6385 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
6391 when Attribute_First => First_Attr :
6395 if Compile_Time_Known_Value (Lo_Bound) then
6396 if Is_Real_Type (P_Type) then
6397 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
6399 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
6402 -- Replace VAX Float_Type'First with a reference to the temporary
6403 -- which represents the low bound of the type. This transformation
6404 -- is needed since the back end cannot evaluate 'First on VAX.
6406 elsif Is_VAX_Float (P_Type)
6407 and then Nkind (Lo_Bound) = N_Identifier
6409 Rewrite (N, New_Reference_To (Entity (Lo_Bound), Sloc (N)));
6413 Check_Concurrent_Discriminant (Lo_Bound);
6421 when Attribute_Fixed_Value =>
6428 when Attribute_Floor =>
6430 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
6436 when Attribute_Fore =>
6437 if Compile_Time_Known_Bounds (P_Type) then
6438 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
6445 when Attribute_Fraction =>
6447 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
6449 -----------------------
6450 -- Has_Access_Values --
6451 -----------------------
6453 when Attribute_Has_Access_Values =>
6454 Rewrite (N, New_Occurrence_Of
6455 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
6456 Analyze_And_Resolve (N, Standard_Boolean);
6458 -----------------------
6459 -- Has_Discriminants --
6460 -----------------------
6462 when Attribute_Has_Discriminants =>
6463 Rewrite (N, New_Occurrence_Of (
6464 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
6465 Analyze_And_Resolve (N, Standard_Boolean);
6467 -----------------------
6468 -- Has_Tagged_Values --
6469 -----------------------
6471 when Attribute_Has_Tagged_Values =>
6472 Rewrite (N, New_Occurrence_Of
6473 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
6474 Analyze_And_Resolve (N, Standard_Boolean);
6480 when Attribute_Identity =>
6487 -- Image is a scalar attribute, but is never static, because it is
6488 -- not a static function (having a non-scalar argument (RM 4.9(22))
6489 -- However, we can constant-fold the image of an enumeration literal
6490 -- if names are available.
6492 when Attribute_Image =>
6493 if Is_Entity_Name (E1)
6494 and then Ekind (Entity (E1)) = E_Enumeration_Literal
6495 and then not Discard_Names (First_Subtype (Etype (E1)))
6496 and then not Global_Discard_Names
6499 Lit : constant Entity_Id := Entity (E1);
6503 Get_Unqualified_Decoded_Name_String (Chars (Lit));
6504 Set_Casing (All_Upper_Case);
6505 Store_String_Chars (Name_Buffer (1 .. Name_Len));
6507 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
6508 Analyze_And_Resolve (N, Standard_String);
6509 Set_Is_Static_Expression (N, False);
6517 -- Img is a scalar attribute, but is never static, because it is
6518 -- not a static function (having a non-scalar argument (RM 4.9(22))
6520 when Attribute_Img =>
6527 -- We never try to fold Integer_Value (though perhaps we could???)
6529 when Attribute_Integer_Value =>
6536 -- Invalid_Value is a scalar attribute that is never static, because
6537 -- the value is by design out of range.
6539 when Attribute_Invalid_Value =>
6546 when Attribute_Large =>
6548 -- For fixed-point, we use the identity:
6550 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6552 if Is_Fixed_Point_Type (P_Type) then
6554 Make_Op_Multiply (Loc,
6556 Make_Op_Subtract (Loc,
6560 Make_Real_Literal (Loc, Ureal_2),
6562 Make_Attribute_Reference (Loc,
6564 Attribute_Name => Name_Mantissa)),
6565 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6568 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6570 Analyze_And_Resolve (N, C_Type);
6572 -- Floating-point (Ada 83 compatibility)
6575 -- Ada 83 attribute is defined as (RM83 3.5.8)
6577 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6581 -- T'Emax = 4 * T'Mantissa
6584 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6592 when Attribute_Last => Last :
6596 if Compile_Time_Known_Value (Hi_Bound) then
6597 if Is_Real_Type (P_Type) then
6598 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6600 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6603 -- Replace VAX Float_Type'Last with a reference to the temporary
6604 -- which represents the high bound of the type. This transformation
6605 -- is needed since the back end cannot evaluate 'Last on VAX.
6607 elsif Is_VAX_Float (P_Type)
6608 and then Nkind (Hi_Bound) = N_Identifier
6610 Rewrite (N, New_Reference_To (Entity (Hi_Bound), Sloc (N)));
6614 Check_Concurrent_Discriminant (Hi_Bound);
6622 when Attribute_Leading_Part =>
6624 Eval_Fat.Leading_Part
6625 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6631 when Attribute_Length => Length : declare
6635 -- If any index type is a formal type, or derived from one, the
6636 -- bounds are not static. Treating them as static can produce
6637 -- spurious warnings or improper constant folding.
6639 Ind := First_Index (P_Type);
6640 while Present (Ind) loop
6641 if Is_Generic_Type (Root_Type (Etype (Ind))) then
6650 -- For two compile time values, we can compute length
6652 if Compile_Time_Known_Value (Lo_Bound)
6653 and then Compile_Time_Known_Value (Hi_Bound)
6656 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6660 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6661 -- comparable, and we can figure out the difference between them.
6664 Diff : aliased Uint;
6668 Compile_Time_Compare
6669 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6672 Fold_Uint (N, Uint_1, False);
6675 Fold_Uint (N, Uint_0, False);
6678 if Diff /= No_Uint then
6679 Fold_Uint (N, Diff + 1, False);
6692 when Attribute_Machine =>
6695 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6702 when Attribute_Machine_Emax =>
6703 Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
6709 when Attribute_Machine_Emin =>
6710 Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
6712 ----------------------
6713 -- Machine_Mantissa --
6714 ----------------------
6716 when Attribute_Machine_Mantissa =>
6717 Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
6719 -----------------------
6720 -- Machine_Overflows --
6721 -----------------------
6723 when Attribute_Machine_Overflows =>
6725 -- Always true for fixed-point
6727 if Is_Fixed_Point_Type (P_Type) then
6728 Fold_Uint (N, True_Value, True);
6730 -- Floating point case
6734 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6742 when Attribute_Machine_Radix =>
6743 if Is_Fixed_Point_Type (P_Type) then
6744 if Is_Decimal_Fixed_Point_Type (P_Type)
6745 and then Machine_Radix_10 (P_Type)
6747 Fold_Uint (N, Uint_10, True);
6749 Fold_Uint (N, Uint_2, True);
6752 -- All floating-point type always have radix 2
6755 Fold_Uint (N, Uint_2, True);
6758 ----------------------
6759 -- Machine_Rounding --
6760 ----------------------
6762 -- Note: for the folding case, it is fine to treat Machine_Rounding
6763 -- exactly the same way as Rounding, since this is one of the allowed
6764 -- behaviors, and performance is not an issue here. It might be a bit
6765 -- better to give the same result as it would give at run time, even
6766 -- though the non-determinism is certainly permitted.
6768 when Attribute_Machine_Rounding =>
6770 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6772 --------------------
6773 -- Machine_Rounds --
6774 --------------------
6776 when Attribute_Machine_Rounds =>
6778 -- Always False for fixed-point
6780 if Is_Fixed_Point_Type (P_Type) then
6781 Fold_Uint (N, False_Value, True);
6783 -- Else yield proper floating-point result
6787 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6794 -- Note: Machine_Size is identical to Object_Size
6796 when Attribute_Machine_Size => Machine_Size : declare
6797 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6800 if Known_Esize (P_TypeA) then
6801 Fold_Uint (N, Esize (P_TypeA), True);
6809 when Attribute_Mantissa =>
6811 -- Fixed-point mantissa
6813 if Is_Fixed_Point_Type (P_Type) then
6815 -- Compile time foldable case
6817 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6819 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6821 -- The calculation of the obsolete Ada 83 attribute Mantissa
6822 -- is annoying, because of AI00143, quoted here:
6824 -- !question 84-01-10
6826 -- Consider the model numbers for F:
6828 -- type F is delta 1.0 range -7.0 .. 8.0;
6830 -- The wording requires that F'MANTISSA be the SMALLEST
6831 -- integer number for which each bound of the specified
6832 -- range is either a model number or lies at most small
6833 -- distant from a model number. This means F'MANTISSA
6834 -- is required to be 3 since the range -7.0 .. 7.0 fits
6835 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6836 -- number, namely, 7. Is this analysis correct? Note that
6837 -- this implies the upper bound of the range is not
6838 -- represented as a model number.
6840 -- !response 84-03-17
6842 -- The analysis is correct. The upper and lower bounds for
6843 -- a fixed point type can lie outside the range of model
6854 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6855 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6856 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6857 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6859 -- If the Bound is exactly a model number, i.e. a multiple
6860 -- of Small, then we back it off by one to get the integer
6861 -- value that must be representable.
6863 if Small_Value (P_Type) * Max_Man = Bound then
6864 Max_Man := Max_Man - 1;
6867 -- Now find corresponding size = Mantissa value
6870 while 2 ** Siz < Max_Man loop
6874 Fold_Uint (N, Siz, True);
6878 -- The case of dynamic bounds cannot be evaluated at compile
6879 -- time. Instead we use a runtime routine (see Exp_Attr).
6884 -- Floating-point Mantissa
6887 Fold_Uint (N, Mantissa, True);
6894 when Attribute_Max => Max :
6896 if Is_Real_Type (P_Type) then
6898 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6900 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6904 ----------------------------------
6905 -- Max_Alignment_For_Allocation --
6906 ----------------------------------
6908 -- Max_Alignment_For_Allocation is usually the Alignment. However,
6909 -- arrays are allocated with dope, so we need to take into account both
6910 -- the alignment of the array, which comes from the component alignment,
6911 -- and the alignment of the dope. Also, if the alignment is unknown, we
6912 -- use the max (it's OK to be pessimistic).
6914 when Attribute_Max_Alignment_For_Allocation =>
6916 A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
6918 if Known_Alignment (P_Type) and then
6919 (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
6921 A := Alignment (P_Type);
6924 Fold_Uint (N, A, Static);
6927 ----------------------------------
6928 -- Max_Size_In_Storage_Elements --
6929 ----------------------------------
6931 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6932 -- Storage_Unit boundary. We can fold any cases for which the size
6933 -- is known by the front end.
6935 when Attribute_Max_Size_In_Storage_Elements =>
6936 if Known_Esize (P_Type) then
6938 (Esize (P_Type) + System_Storage_Unit - 1) /
6939 System_Storage_Unit,
6943 --------------------
6944 -- Mechanism_Code --
6945 --------------------
6947 when Attribute_Mechanism_Code =>
6951 Mech : Mechanism_Type;
6955 Mech := Mechanism (P_Entity);
6958 Val := UI_To_Int (Expr_Value (E1));
6960 Formal := First_Formal (P_Entity);
6961 for J in 1 .. Val - 1 loop
6962 Next_Formal (Formal);
6964 Mech := Mechanism (Formal);
6968 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6976 when Attribute_Min => Min :
6978 if Is_Real_Type (P_Type) then
6980 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6983 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6991 when Attribute_Mod =>
6993 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6999 when Attribute_Model =>
7001 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
7007 when Attribute_Model_Emin =>
7008 Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
7014 when Attribute_Model_Epsilon =>
7015 Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
7017 --------------------
7018 -- Model_Mantissa --
7019 --------------------
7021 when Attribute_Model_Mantissa =>
7022 Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
7028 when Attribute_Model_Small =>
7029 Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
7035 when Attribute_Modulus =>
7036 Fold_Uint (N, Modulus (P_Type), True);
7038 --------------------
7039 -- Null_Parameter --
7040 --------------------
7042 -- Cannot fold, we know the value sort of, but the whole point is
7043 -- that there is no way to talk about this imaginary value except
7044 -- by using the attribute, so we leave it the way it is.
7046 when Attribute_Null_Parameter =>
7053 -- The Object_Size attribute for a type returns the Esize of the
7054 -- type and can be folded if this value is known.
7056 when Attribute_Object_Size => Object_Size : declare
7057 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7060 if Known_Esize (P_TypeA) then
7061 Fold_Uint (N, Esize (P_TypeA), True);
7065 ----------------------
7066 -- Overlaps_Storage --
7067 ----------------------
7069 when Attribute_Overlaps_Storage =>
7072 -------------------------
7073 -- Passed_By_Reference --
7074 -------------------------
7076 -- Scalar types are never passed by reference
7078 when Attribute_Passed_By_Reference =>
7079 Fold_Uint (N, False_Value, True);
7085 when Attribute_Pos =>
7086 Fold_Uint (N, Expr_Value (E1), True);
7092 when Attribute_Pred => Pred :
7094 -- Floating-point case
7096 if Is_Floating_Point_Type (P_Type) then
7098 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
7102 elsif Is_Fixed_Point_Type (P_Type) then
7104 Expr_Value_R (E1) - Small_Value (P_Type), True);
7106 -- Modular integer case (wraps)
7108 elsif Is_Modular_Integer_Type (P_Type) then
7109 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
7111 -- Other scalar cases
7114 pragma Assert (Is_Scalar_Type (P_Type));
7116 if Is_Enumeration_Type (P_Type)
7117 and then Expr_Value (E1) =
7118 Expr_Value (Type_Low_Bound (P_Base_Type))
7120 Apply_Compile_Time_Constraint_Error
7121 (N, "Pred of `&''First`",
7122 CE_Overflow_Check_Failed,
7124 Warn => not Static);
7130 Fold_Uint (N, Expr_Value (E1) - 1, Static);
7138 -- No processing required, because by this stage, Range has been
7139 -- replaced by First .. Last, so this branch can never be taken.
7141 when Attribute_Range =>
7142 raise Program_Error;
7148 when Attribute_Range_Length =>
7151 -- Can fold if both bounds are compile time known
7153 if Compile_Time_Known_Value (Hi_Bound)
7154 and then Compile_Time_Known_Value (Lo_Bound)
7158 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
7162 -- One more case is where Hi_Bound and Lo_Bound are compile-time
7163 -- comparable, and we can figure out the difference between them.
7166 Diff : aliased Uint;
7170 Compile_Time_Compare
7171 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
7174 Fold_Uint (N, Uint_1, False);
7177 Fold_Uint (N, Uint_0, False);
7180 if Diff /= No_Uint then
7181 Fold_Uint (N, Diff + 1, False);
7193 when Attribute_Ref =>
7194 Fold_Uint (N, Expr_Value (E1), True);
7200 when Attribute_Remainder => Remainder : declare
7201 X : constant Ureal := Expr_Value_R (E1);
7202 Y : constant Ureal := Expr_Value_R (E2);
7205 if UR_Is_Zero (Y) then
7206 Apply_Compile_Time_Constraint_Error
7207 (N, "division by zero in Remainder",
7208 CE_Overflow_Check_Failed,
7209 Warn => not Static);
7215 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
7222 when Attribute_Round => Round :
7228 -- First we get the (exact result) in units of small
7230 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
7232 -- Now round that exactly to an integer
7234 Si := UR_To_Uint (Sr);
7236 -- Finally the result is obtained by converting back to real
7238 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
7245 when Attribute_Rounding =>
7247 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
7253 when Attribute_Safe_Emax =>
7254 Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
7260 when Attribute_Safe_First =>
7261 Fold_Ureal (N, Safe_First_Value (P_Type), Static);
7267 when Attribute_Safe_Large =>
7268 if Is_Fixed_Point_Type (P_Type) then
7270 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
7272 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
7279 when Attribute_Safe_Last =>
7280 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
7286 when Attribute_Safe_Small =>
7288 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
7289 -- for fixed-point, since is the same as Small, but we implement
7290 -- it for backwards compatibility.
7292 if Is_Fixed_Point_Type (P_Type) then
7293 Fold_Ureal (N, Small_Value (P_Type), Static);
7295 -- Ada 83 Safe_Small for floating-point cases
7298 Fold_Ureal (N, Model_Small_Value (P_Type), Static);
7305 when Attribute_Same_Storage =>
7312 when Attribute_Scale =>
7313 Fold_Uint (N, Scale_Value (P_Type), True);
7319 when Attribute_Scaling =>
7322 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
7328 when Attribute_Signed_Zeros =>
7330 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
7336 -- Size attribute returns the RM size. All scalar types can be folded,
7337 -- as well as any types for which the size is known by the front end,
7338 -- including any type for which a size attribute is specified.
7340 when Attribute_Size | Attribute_VADS_Size => Size : declare
7341 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7344 if RM_Size (P_TypeA) /= Uint_0 then
7348 if Id = Attribute_VADS_Size or else Use_VADS_Size then
7350 S : constant Node_Id := Size_Clause (P_TypeA);
7353 -- If a size clause applies, then use the size from it.
7354 -- This is one of the rare cases where we can use the
7355 -- Size_Clause field for a subtype when Has_Size_Clause
7356 -- is False. Consider:
7358 -- type x is range 1 .. 64;
7359 -- for x'size use 12;
7360 -- subtype y is x range 0 .. 3;
7362 -- Here y has a size clause inherited from x, but normally
7363 -- it does not apply, and y'size is 2. However, y'VADS_Size
7364 -- is indeed 12 and not 2.
7367 and then Is_OK_Static_Expression (Expression (S))
7369 Fold_Uint (N, Expr_Value (Expression (S)), True);
7371 -- If no size is specified, then we simply use the object
7372 -- size in the VADS_Size case (e.g. Natural'Size is equal
7373 -- to Integer'Size, not one less).
7376 Fold_Uint (N, Esize (P_TypeA), True);
7380 -- Normal case (Size) in which case we want the RM_Size
7385 Static and then Is_Discrete_Type (P_TypeA));
7394 when Attribute_Small =>
7396 -- The floating-point case is present only for Ada 83 compatibility.
7397 -- Note that strictly this is an illegal addition, since we are
7398 -- extending an Ada 95 defined attribute, but we anticipate an
7399 -- ARG ruling that will permit this.
7401 if Is_Floating_Point_Type (P_Type) then
7403 -- Ada 83 attribute is defined as (RM83 3.5.8)
7405 -- T'Small = 2.0**(-T'Emax - 1)
7409 -- T'Emax = 4 * T'Mantissa
7411 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
7413 -- Normal Ada 95 fixed-point case
7416 Fold_Ureal (N, Small_Value (P_Type), True);
7423 when Attribute_Stream_Size =>
7430 when Attribute_Succ => Succ :
7432 -- Floating-point case
7434 if Is_Floating_Point_Type (P_Type) then
7436 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
7440 elsif Is_Fixed_Point_Type (P_Type) then
7442 Expr_Value_R (E1) + Small_Value (P_Type), Static);
7444 -- Modular integer case (wraps)
7446 elsif Is_Modular_Integer_Type (P_Type) then
7447 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
7449 -- Other scalar cases
7452 pragma Assert (Is_Scalar_Type (P_Type));
7454 if Is_Enumeration_Type (P_Type)
7455 and then Expr_Value (E1) =
7456 Expr_Value (Type_High_Bound (P_Base_Type))
7458 Apply_Compile_Time_Constraint_Error
7459 (N, "Succ of `&''Last`",
7460 CE_Overflow_Check_Failed,
7462 Warn => not Static);
7467 Fold_Uint (N, Expr_Value (E1) + 1, Static);
7476 when Attribute_Truncation =>
7478 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
7484 when Attribute_Type_Class => Type_Class : declare
7485 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
7489 if Is_Descendent_Of_Address (Typ) then
7490 Id := RE_Type_Class_Address;
7492 elsif Is_Enumeration_Type (Typ) then
7493 Id := RE_Type_Class_Enumeration;
7495 elsif Is_Integer_Type (Typ) then
7496 Id := RE_Type_Class_Integer;
7498 elsif Is_Fixed_Point_Type (Typ) then
7499 Id := RE_Type_Class_Fixed_Point;
7501 elsif Is_Floating_Point_Type (Typ) then
7502 Id := RE_Type_Class_Floating_Point;
7504 elsif Is_Array_Type (Typ) then
7505 Id := RE_Type_Class_Array;
7507 elsif Is_Record_Type (Typ) then
7508 Id := RE_Type_Class_Record;
7510 elsif Is_Access_Type (Typ) then
7511 Id := RE_Type_Class_Access;
7513 elsif Is_Enumeration_Type (Typ) then
7514 Id := RE_Type_Class_Enumeration;
7516 elsif Is_Task_Type (Typ) then
7517 Id := RE_Type_Class_Task;
7519 -- We treat protected types like task types. It would make more
7520 -- sense to have another enumeration value, but after all the
7521 -- whole point of this feature is to be exactly DEC compatible,
7522 -- and changing the type Type_Class would not meet this requirement.
7524 elsif Is_Protected_Type (Typ) then
7525 Id := RE_Type_Class_Task;
7527 -- Not clear if there are any other possibilities, but if there
7528 -- are, then we will treat them as the address case.
7531 Id := RE_Type_Class_Address;
7534 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
7537 -----------------------
7538 -- Unbiased_Rounding --
7539 -----------------------
7541 when Attribute_Unbiased_Rounding =>
7543 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7546 -------------------------
7547 -- Unconstrained_Array --
7548 -------------------------
7550 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7551 Typ : constant Entity_Id := Underlying_Type (P_Type);
7554 Rewrite (N, New_Occurrence_Of (
7556 Is_Array_Type (P_Type)
7557 and then not Is_Constrained (Typ)), Loc));
7559 -- Analyze and resolve as boolean, note that this attribute is
7560 -- a static attribute in GNAT.
7562 Analyze_And_Resolve (N, Standard_Boolean);
7564 end Unconstrained_Array;
7570 -- Processing is shared with Size
7576 when Attribute_Val => Val :
7578 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7580 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7582 Apply_Compile_Time_Constraint_Error
7583 (N, "Val expression out of range",
7584 CE_Range_Check_Failed,
7585 Warn => not Static);
7591 Fold_Uint (N, Expr_Value (E1), Static);
7599 -- The Value_Size attribute for a type returns the RM size of the
7600 -- type. This an always be folded for scalar types, and can also
7601 -- be folded for non-scalar types if the size is set.
7603 when Attribute_Value_Size => Value_Size : declare
7604 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7606 if RM_Size (P_TypeA) /= Uint_0 then
7607 Fold_Uint (N, RM_Size (P_TypeA), True);
7615 -- Version can never be static
7617 when Attribute_Version =>
7624 -- Wide_Image is a scalar attribute, but is never static, because it
7625 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7627 when Attribute_Wide_Image =>
7630 ---------------------
7631 -- Wide_Wide_Image --
7632 ---------------------
7634 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7635 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7637 when Attribute_Wide_Wide_Image =>
7640 ---------------------
7641 -- Wide_Wide_Width --
7642 ---------------------
7644 -- Processing for Wide_Wide_Width is combined with Width
7650 -- Processing for Wide_Width is combined with Width
7656 -- This processing also handles the case of Wide_[Wide_]Width
7658 when Attribute_Width |
7659 Attribute_Wide_Width |
7660 Attribute_Wide_Wide_Width => Width :
7662 if Compile_Time_Known_Bounds (P_Type) then
7664 -- Floating-point types
7666 if Is_Floating_Point_Type (P_Type) then
7668 -- Width is zero for a null range (RM 3.5 (38))
7670 if Expr_Value_R (Type_High_Bound (P_Type)) <
7671 Expr_Value_R (Type_Low_Bound (P_Type))
7673 Fold_Uint (N, Uint_0, True);
7676 -- For floating-point, we have +N.dddE+nnn where length
7677 -- of ddd is determined by type'Digits - 1, but is one
7678 -- if Digits is one (RM 3.5 (33)).
7680 -- nnn is set to 2 for Short_Float and Float (32 bit
7681 -- floats), and 3 for Long_Float and Long_Long_Float.
7682 -- For machines where Long_Long_Float is the IEEE
7683 -- extended precision type, the exponent takes 4 digits.
7687 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7690 if Esize (P_Type) <= 32 then
7692 elsif Esize (P_Type) = 64 then
7698 Fold_Uint (N, UI_From_Int (Len), True);
7702 -- Fixed-point types
7704 elsif Is_Fixed_Point_Type (P_Type) then
7706 -- Width is zero for a null range (RM 3.5 (38))
7708 if Expr_Value (Type_High_Bound (P_Type)) <
7709 Expr_Value (Type_Low_Bound (P_Type))
7711 Fold_Uint (N, Uint_0, True);
7713 -- The non-null case depends on the specific real type
7716 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7719 (N, UI_From_Int (Fore_Value + 1) + Aft_Value (P_Type),
7727 R : constant Entity_Id := Root_Type (P_Type);
7728 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7729 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7742 -- Width for types derived from Standard.Character
7743 -- and Standard.Wide_[Wide_]Character.
7745 elsif Is_Standard_Character_Type (P_Type) then
7748 -- Set W larger if needed
7750 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7752 -- All wide characters look like Hex_hhhhhhhh
7756 -- No need to compute this more than once!
7761 C := Character'Val (J);
7763 -- Test for all cases where Character'Image
7764 -- yields an image that is longer than three
7765 -- characters. First the cases of Reserved_xxx
7766 -- names (length = 12).
7769 when Reserved_128 | Reserved_129 |
7770 Reserved_132 | Reserved_153
7773 when BS | HT | LF | VT | FF | CR |
7774 SO | SI | EM | FS | GS | RS |
7775 US | RI | MW | ST | PM
7778 when NUL | SOH | STX | ETX | EOT |
7779 ENQ | ACK | BEL | DLE | DC1 |
7780 DC2 | DC3 | DC4 | NAK | SYN |
7781 ETB | CAN | SUB | ESC | DEL |
7782 BPH | NBH | NEL | SSA | ESA |
7783 HTS | HTJ | VTS | PLD | PLU |
7784 SS2 | SS3 | DCS | PU1 | PU2 |
7785 STS | CCH | SPA | EPA | SOS |
7786 SCI | CSI | OSC | APC
7789 when Space .. Tilde |
7790 No_Break_Space .. LC_Y_Diaeresis
7792 -- Special case of soft hyphen in Ada 2005
7794 if C = Character'Val (16#AD#)
7795 and then Ada_Version >= Ada_2005
7803 W := Int'Max (W, Wt);
7807 -- Width for types derived from Standard.Boolean
7809 elsif R = Standard_Boolean then
7816 -- Width for integer types
7818 elsif Is_Integer_Type (P_Type) then
7819 T := UI_Max (abs Lo, abs Hi);
7827 -- Only remaining possibility is user declared enum type
7830 pragma Assert (Is_Enumeration_Type (P_Type));
7833 L := First_Literal (P_Type);
7835 while Present (L) loop
7837 -- Only pay attention to in range characters
7839 if Lo <= Enumeration_Pos (L)
7840 and then Enumeration_Pos (L) <= Hi
7842 -- For Width case, use decoded name
7844 if Id = Attribute_Width then
7845 Get_Decoded_Name_String (Chars (L));
7846 Wt := Nat (Name_Len);
7848 -- For Wide_[Wide_]Width, use encoded name, and
7849 -- then adjust for the encoding.
7852 Get_Name_String (Chars (L));
7854 -- Character literals are always of length 3
7856 if Name_Buffer (1) = 'Q' then
7859 -- Otherwise loop to adjust for upper/wide chars
7862 Wt := Nat (Name_Len);
7864 for J in 1 .. Name_Len loop
7865 if Name_Buffer (J) = 'U' then
7867 elsif Name_Buffer (J) = 'W' then
7874 W := Int'Max (W, Wt);
7881 Fold_Uint (N, UI_From_Int (W), True);
7887 -- The following attributes denote functions that cannot be folded
7889 when Attribute_From_Any |
7891 Attribute_TypeCode =>
7894 -- The following attributes can never be folded, and furthermore we
7895 -- should not even have entered the case statement for any of these.
7896 -- Note that in some cases, the values have already been folded as
7897 -- a result of the processing in Analyze_Attribute.
7899 when Attribute_Abort_Signal |
7902 Attribute_Address_Size |
7903 Attribute_Asm_Input |
7904 Attribute_Asm_Output |
7906 Attribute_Bit_Order |
7907 Attribute_Bit_Position |
7908 Attribute_Callable |
7911 Attribute_Code_Address |
7912 Attribute_Compiler_Version |
7914 Attribute_Default_Bit_Order |
7915 Attribute_Elaborated |
7916 Attribute_Elab_Body |
7917 Attribute_Elab_Spec |
7918 Attribute_Elab_Subp_Body |
7920 Attribute_External_Tag |
7921 Attribute_Fast_Math |
7922 Attribute_First_Bit |
7924 Attribute_Last_Bit |
7925 Attribute_Maximum_Alignment |
7928 Attribute_Partition_ID |
7929 Attribute_Pool_Address |
7930 Attribute_Position |
7931 Attribute_Priority |
7934 Attribute_Storage_Pool |
7935 Attribute_Storage_Size |
7936 Attribute_Storage_Unit |
7937 Attribute_Stub_Type |
7938 Attribute_System_Allocator_Alignment |
7940 Attribute_Target_Name |
7941 Attribute_Terminated |
7942 Attribute_To_Address |
7943 Attribute_Type_Key |
7944 Attribute_UET_Address |
7945 Attribute_Unchecked_Access |
7946 Attribute_Universal_Literal_String |
7947 Attribute_Unrestricted_Access |
7950 Attribute_Wchar_T_Size |
7951 Attribute_Wide_Value |
7952 Attribute_Wide_Wide_Value |
7953 Attribute_Word_Size |
7956 raise Program_Error;
7959 -- At the end of the case, one more check. If we did a static evaluation
7960 -- so that the result is now a literal, then set Is_Static_Expression
7961 -- in the constant only if the prefix type is a static subtype. For
7962 -- non-static subtypes, the folding is still OK, but not static.
7964 -- An exception is the GNAT attribute Constrained_Array which is
7965 -- defined to be a static attribute in all cases.
7967 if Nkind_In (N, N_Integer_Literal,
7969 N_Character_Literal,
7971 or else (Is_Entity_Name (N)
7972 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7974 Set_Is_Static_Expression (N, Static);
7976 -- If this is still an attribute reference, then it has not been folded
7977 -- and that means that its expressions are in a non-static context.
7979 elsif Nkind (N) = N_Attribute_Reference then
7982 -- Note: the else case not covered here are odd cases where the
7983 -- processing has transformed the attribute into something other
7984 -- than a constant. Nothing more to do in such cases.
7991 ------------------------------
7992 -- Is_Anonymous_Tagged_Base --
7993 ------------------------------
7995 function Is_Anonymous_Tagged_Base
8002 Anon = Current_Scope
8003 and then Is_Itype (Anon)
8004 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
8005 end Is_Anonymous_Tagged_Base;
8007 --------------------------------
8008 -- Name_Implies_Lvalue_Prefix --
8009 --------------------------------
8011 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
8012 pragma Assert (Is_Attribute_Name (Nam));
8014 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
8015 end Name_Implies_Lvalue_Prefix;
8017 -----------------------
8018 -- Resolve_Attribute --
8019 -----------------------
8021 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
8022 Loc : constant Source_Ptr := Sloc (N);
8023 P : constant Node_Id := Prefix (N);
8024 Aname : constant Name_Id := Attribute_Name (N);
8025 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
8026 Btyp : constant Entity_Id := Base_Type (Typ);
8027 Des_Btyp : Entity_Id;
8028 Index : Interp_Index;
8030 Nom_Subt : Entity_Id;
8032 procedure Accessibility_Message;
8033 -- Error, or warning within an instance, if the static accessibility
8034 -- rules of 3.10.2 are violated.
8036 ---------------------------
8037 -- Accessibility_Message --
8038 ---------------------------
8040 procedure Accessibility_Message is
8041 Indic : Node_Id := Parent (Parent (N));
8044 -- In an instance, this is a runtime check, but one we
8045 -- know will fail, so generate an appropriate warning.
8047 if In_Instance_Body then
8048 Error_Msg_F ("?non-local pointer cannot point to local object", P);
8050 ("\?Program_Error will be raised at run time", P);
8052 Make_Raise_Program_Error (Loc,
8053 Reason => PE_Accessibility_Check_Failed));
8058 Error_Msg_F ("non-local pointer cannot point to local object", P);
8060 -- Check for case where we have a missing access definition
8062 if Is_Record_Type (Current_Scope)
8064 Nkind_In (Parent (N), N_Discriminant_Association,
8065 N_Index_Or_Discriminant_Constraint)
8067 Indic := Parent (Parent (N));
8068 while Present (Indic)
8069 and then Nkind (Indic) /= N_Subtype_Indication
8071 Indic := Parent (Indic);
8074 if Present (Indic) then
8076 ("\use an access definition for" &
8077 " the access discriminant of&",
8078 N, Entity (Subtype_Mark (Indic)));
8082 end Accessibility_Message;
8084 -- Start of processing for Resolve_Attribute
8087 -- If error during analysis, no point in continuing, except for array
8088 -- types, where we get better recovery by using unconstrained indexes
8089 -- than nothing at all (see Check_Array_Type).
8092 and then Attr_Id /= Attribute_First
8093 and then Attr_Id /= Attribute_Last
8094 and then Attr_Id /= Attribute_Length
8095 and then Attr_Id /= Attribute_Range
8100 -- If attribute was universal type, reset to actual type
8102 if Etype (N) = Universal_Integer
8103 or else Etype (N) = Universal_Real
8108 -- Remaining processing depends on attribute
8116 -- For access attributes, if the prefix denotes an entity, it is
8117 -- interpreted as a name, never as a call. It may be overloaded,
8118 -- in which case resolution uses the profile of the context type.
8119 -- Otherwise prefix must be resolved.
8121 when Attribute_Access
8122 | Attribute_Unchecked_Access
8123 | Attribute_Unrestricted_Access =>
8127 if Is_Variable (P) then
8128 Note_Possible_Modification (P, Sure => False);
8131 -- The following comes from a query by Adam Beneschan, concerning
8132 -- improper use of universal_access in equality tests involving
8133 -- anonymous access types. Another good reason for 'Ref, but
8134 -- for now disable the test, which breaks several filed tests.
8136 if Ekind (Typ) = E_Anonymous_Access_Type
8137 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
8140 Error_Msg_N ("need unique type to resolve 'Access", N);
8141 Error_Msg_N ("\qualify attribute with some access type", N);
8144 if Is_Entity_Name (P) then
8145 if Is_Overloaded (P) then
8146 Get_First_Interp (P, Index, It);
8147 while Present (It.Nam) loop
8148 if Type_Conformant (Designated_Type (Typ), It.Nam) then
8149 Set_Entity (P, It.Nam);
8151 -- The prefix is definitely NOT overloaded anymore at
8152 -- this point, so we reset the Is_Overloaded flag to
8153 -- avoid any confusion when reanalyzing the node.
8155 Set_Is_Overloaded (P, False);
8156 Set_Is_Overloaded (N, False);
8157 Generate_Reference (Entity (P), P);
8161 Get_Next_Interp (Index, It);
8164 -- If Prefix is a subprogram name, it is frozen by this
8167 -- If it is a type, there is nothing to resolve.
8168 -- If it is an object, complete its resolution.
8170 elsif Is_Overloadable (Entity (P)) then
8172 -- Avoid insertion of freeze actions in spec expression mode
8174 if not In_Spec_Expression then
8175 Freeze_Before (N, Entity (P));
8178 elsif Is_Type (Entity (P)) then
8184 Error_Msg_Name_1 := Aname;
8186 if not Is_Entity_Name (P) then
8189 elsif Is_Overloadable (Entity (P))
8190 and then Is_Abstract_Subprogram (Entity (P))
8192 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
8193 Set_Etype (N, Any_Type);
8195 elsif Convention (Entity (P)) = Convention_Intrinsic then
8196 if Ekind (Entity (P)) = E_Enumeration_Literal then
8198 ("prefix of % attribute cannot be enumeration literal",
8202 ("prefix of % attribute cannot be intrinsic", P);
8205 Set_Etype (N, Any_Type);
8208 -- Assignments, return statements, components of aggregates,
8209 -- generic instantiations will require convention checks if
8210 -- the type is an access to subprogram. Given that there will
8211 -- also be accessibility checks on those, this is where the
8212 -- checks can eventually be centralized ???
8214 if Ekind_In (Btyp, E_Access_Subprogram_Type,
8215 E_Anonymous_Access_Subprogram_Type,
8216 E_Access_Protected_Subprogram_Type,
8217 E_Anonymous_Access_Protected_Subprogram_Type)
8219 -- Deal with convention mismatch
8221 if Convention (Designated_Type (Btyp)) /=
8222 Convention (Entity (P))
8225 ("subprogram & has wrong convention", P, Entity (P));
8227 ("\does not match convention of access type &",
8230 if not Has_Convention_Pragma (Btyp) then
8232 ("\probable missing pragma Convention for &",
8237 Check_Subtype_Conformant
8238 (New_Id => Entity (P),
8239 Old_Id => Designated_Type (Btyp),
8243 if Attr_Id = Attribute_Unchecked_Access then
8244 Error_Msg_Name_1 := Aname;
8246 ("attribute% cannot be applied to a subprogram", P);
8248 elsif Aname = Name_Unrestricted_Access then
8249 null; -- Nothing to check
8251 -- Check the static accessibility rule of 3.10.2(32).
8252 -- This rule also applies within the private part of an
8253 -- instantiation. This rule does not apply to anonymous
8254 -- access-to-subprogram types in access parameters.
8256 elsif Attr_Id = Attribute_Access
8257 and then not In_Instance_Body
8259 (Ekind (Btyp) = E_Access_Subprogram_Type
8260 or else Is_Local_Anonymous_Access (Btyp))
8262 and then Subprogram_Access_Level (Entity (P)) >
8263 Type_Access_Level (Btyp)
8266 ("subprogram must not be deeper than access type", P);
8268 -- Check the restriction of 3.10.2(32) that disallows the
8269 -- access attribute within a generic body when the ultimate
8270 -- ancestor of the type of the attribute is declared outside
8271 -- of the generic unit and the subprogram is declared within
8272 -- that generic unit. This includes any such attribute that
8273 -- occurs within the body of a generic unit that is a child
8274 -- of the generic unit where the subprogram is declared.
8276 -- The rule also prohibits applying the attribute when the
8277 -- access type is a generic formal access type (since the
8278 -- level of the actual type is not known). This restriction
8279 -- does not apply when the attribute type is an anonymous
8280 -- access-to-subprogram type. Note that this check was
8281 -- revised by AI-229, because the originally Ada 95 rule
8282 -- was too lax. The original rule only applied when the
8283 -- subprogram was declared within the body of the generic,
8284 -- which allowed the possibility of dangling references).
8285 -- The rule was also too strict in some case, in that it
8286 -- didn't permit the access to be declared in the generic
8287 -- spec, whereas the revised rule does (as long as it's not
8290 -- There are a couple of subtleties of the test for applying
8291 -- the check that are worth noting. First, we only apply it
8292 -- when the levels of the subprogram and access type are the
8293 -- same (the case where the subprogram is statically deeper
8294 -- was applied above, and the case where the type is deeper
8295 -- is always safe). Second, we want the check to apply
8296 -- within nested generic bodies and generic child unit
8297 -- bodies, but not to apply to an attribute that appears in
8298 -- the generic unit's specification. This is done by testing
8299 -- that the attribute's innermost enclosing generic body is
8300 -- not the same as the innermost generic body enclosing the
8301 -- generic unit where the subprogram is declared (we don't
8302 -- want the check to apply when the access attribute is in
8303 -- the spec and there's some other generic body enclosing
8304 -- generic). Finally, there's no point applying the check
8305 -- when within an instance, because any violations will have
8306 -- been caught by the compilation of the generic unit.
8308 -- Note that we relax this check in CodePeer mode for
8309 -- compatibility with legacy code, since CodePeer is an
8310 -- Ada source code analyzer, not a strict compiler.
8311 -- ??? Note that a better approach would be to have a
8312 -- separate switch to relax this rule, and enable this
8313 -- switch in CodePeer mode.
8315 elsif Attr_Id = Attribute_Access
8316 and then not CodePeer_Mode
8317 and then not In_Instance
8318 and then Present (Enclosing_Generic_Unit (Entity (P)))
8319 and then Present (Enclosing_Generic_Body (N))
8320 and then Enclosing_Generic_Body (N) /=
8321 Enclosing_Generic_Body
8322 (Enclosing_Generic_Unit (Entity (P)))
8323 and then Subprogram_Access_Level (Entity (P)) =
8324 Type_Access_Level (Btyp)
8325 and then Ekind (Btyp) /=
8326 E_Anonymous_Access_Subprogram_Type
8327 and then Ekind (Btyp) /=
8328 E_Anonymous_Access_Protected_Subprogram_Type
8330 -- The attribute type's ultimate ancestor must be
8331 -- declared within the same generic unit as the
8332 -- subprogram is declared. The error message is
8333 -- specialized to say "ancestor" for the case where the
8334 -- access type is not its own ancestor, since saying
8335 -- simply "access type" would be very confusing.
8337 if Enclosing_Generic_Unit (Entity (P)) /=
8338 Enclosing_Generic_Unit (Root_Type (Btyp))
8341 ("''Access attribute not allowed in generic body",
8344 if Root_Type (Btyp) = Btyp then
8347 "access type & is declared outside " &
8348 "generic unit (RM 3.10.2(32))", N, Btyp);
8351 ("\because ancestor of " &
8352 "access type & is declared outside " &
8353 "generic unit (RM 3.10.2(32))", N, Btyp);
8357 ("\move ''Access to private part, or " &
8358 "(Ada 2005) use anonymous access type instead of &",
8361 -- If the ultimate ancestor of the attribute's type is
8362 -- a formal type, then the attribute is illegal because
8363 -- the actual type might be declared at a higher level.
8364 -- The error message is specialized to say "ancestor"
8365 -- for the case where the access type is not its own
8366 -- ancestor, since saying simply "access type" would be
8369 elsif Is_Generic_Type (Root_Type (Btyp)) then
8370 if Root_Type (Btyp) = Btyp then
8372 ("access type must not be a generic formal type",
8376 ("ancestor access type must not be a generic " &
8383 -- If this is a renaming, an inherited operation, or a
8384 -- subprogram instance, use the original entity. This may make
8385 -- the node type-inconsistent, so this transformation can only
8386 -- be done if the node will not be reanalyzed. In particular,
8387 -- if it is within a default expression, the transformation
8388 -- must be delayed until the default subprogram is created for
8389 -- it, when the enclosing subprogram is frozen.
8391 if Is_Entity_Name (P)
8392 and then Is_Overloadable (Entity (P))
8393 and then Present (Alias (Entity (P)))
8394 and then Expander_Active
8397 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8400 elsif Nkind (P) = N_Selected_Component
8401 and then Is_Overloadable (Entity (Selector_Name (P)))
8403 -- Protected operation. If operation is overloaded, must
8404 -- disambiguate. Prefix that denotes protected object itself
8405 -- is resolved with its own type.
8407 if Attr_Id = Attribute_Unchecked_Access then
8408 Error_Msg_Name_1 := Aname;
8410 ("attribute% cannot be applied to protected operation", P);
8413 Resolve (Prefix (P));
8414 Generate_Reference (Entity (Selector_Name (P)), P);
8416 elsif Is_Overloaded (P) then
8418 -- Use the designated type of the context to disambiguate
8419 -- Note that this was not strictly conformant to Ada 95,
8420 -- but was the implementation adopted by most Ada 95 compilers.
8421 -- The use of the context type to resolve an Access attribute
8422 -- reference is now mandated in AI-235 for Ada 2005.
8425 Index : Interp_Index;
8429 Get_First_Interp (P, Index, It);
8430 while Present (It.Typ) loop
8431 if Covers (Designated_Type (Typ), It.Typ) then
8432 Resolve (P, It.Typ);
8436 Get_Next_Interp (Index, It);
8443 -- X'Access is illegal if X denotes a constant and the access type
8444 -- is access-to-variable. Same for 'Unchecked_Access. The rule
8445 -- does not apply to 'Unrestricted_Access. If the reference is a
8446 -- default-initialized aggregate component for a self-referential
8447 -- type the reference is legal.
8449 if not (Ekind (Btyp) = E_Access_Subprogram_Type
8450 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
8451 or else (Is_Record_Type (Btyp)
8453 Present (Corresponding_Remote_Type (Btyp)))
8454 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8455 or else Ekind (Btyp)
8456 = E_Anonymous_Access_Protected_Subprogram_Type
8457 or else Is_Access_Constant (Btyp)
8458 or else Is_Variable (P)
8459 or else Attr_Id = Attribute_Unrestricted_Access)
8461 if Is_Entity_Name (P)
8462 and then Is_Type (Entity (P))
8464 -- Legality of a self-reference through an access
8465 -- attribute has been verified in Analyze_Access_Attribute.
8469 elsif Comes_From_Source (N) then
8470 Error_Msg_F ("access-to-variable designates constant", P);
8474 Des_Btyp := Designated_Type (Btyp);
8476 if Ada_Version >= Ada_2005
8477 and then Is_Incomplete_Type (Des_Btyp)
8479 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
8480 -- imported entity, and the non-limited view is visible, make
8481 -- use of it. If it is an incomplete subtype, use the base type
8484 if From_With_Type (Des_Btyp)
8485 and then Present (Non_Limited_View (Des_Btyp))
8487 Des_Btyp := Non_Limited_View (Des_Btyp);
8489 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
8490 Des_Btyp := Etype (Des_Btyp);
8494 if (Attr_Id = Attribute_Access
8496 Attr_Id = Attribute_Unchecked_Access)
8497 and then (Ekind (Btyp) = E_General_Access_Type
8498 or else Ekind (Btyp) = E_Anonymous_Access_Type)
8500 -- Ada 2005 (AI-230): Check the accessibility of anonymous
8501 -- access types for stand-alone objects, record and array
8502 -- components, and return objects. For a component definition
8503 -- the level is the same of the enclosing composite type.
8505 if Ada_Version >= Ada_2005
8506 and then (Is_Local_Anonymous_Access (Btyp)
8508 -- Handle cases where Btyp is the
8509 -- anonymous access type of an Ada 2012
8510 -- stand-alone object.
8512 or else Nkind (Associated_Node_For_Itype (Btyp)) =
8513 N_Object_Declaration)
8514 and then Object_Access_Level (P)
8515 > Deepest_Type_Access_Level (Btyp)
8516 and then Attr_Id = Attribute_Access
8518 -- In an instance, this is a runtime check, but one we
8519 -- know will fail, so generate an appropriate warning.
8521 if In_Instance_Body then
8523 ("?non-local pointer cannot point to local object", P);
8525 ("\?Program_Error will be raised at run time", P);
8527 Make_Raise_Program_Error (Loc,
8528 Reason => PE_Accessibility_Check_Failed));
8533 ("non-local pointer cannot point to local object", P);
8537 if Is_Dependent_Component_Of_Mutable_Object (P) then
8539 ("illegal attribute for discriminant-dependent component",
8543 -- Check static matching rule of 3.10.2(27). Nominal subtype
8544 -- of the prefix must statically match the designated type.
8546 Nom_Subt := Etype (P);
8548 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
8549 Nom_Subt := Base_Type (Nom_Subt);
8552 if Is_Tagged_Type (Designated_Type (Typ)) then
8554 -- If the attribute is in the context of an access
8555 -- parameter, then the prefix is allowed to be of the
8556 -- class-wide type (by AI-127).
8558 if Ekind (Typ) = E_Anonymous_Access_Type then
8559 if not Covers (Designated_Type (Typ), Nom_Subt)
8560 and then not Covers (Nom_Subt, Designated_Type (Typ))
8566 Desig := Designated_Type (Typ);
8568 if Is_Class_Wide_Type (Desig) then
8569 Desig := Etype (Desig);
8572 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8577 ("type of prefix: & not compatible",
8580 ("\with &, the expected designated type",
8581 P, Designated_Type (Typ));
8586 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8588 (not Is_Class_Wide_Type (Designated_Type (Typ))
8589 and then Is_Class_Wide_Type (Nom_Subt))
8592 ("type of prefix: & is not covered", P, Nom_Subt);
8594 ("\by &, the expected designated type" &
8595 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8598 if Is_Class_Wide_Type (Designated_Type (Typ))
8599 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8600 and then Is_Constrained (Etype (Designated_Type (Typ)))
8601 and then Designated_Type (Typ) /= Nom_Subt
8603 Apply_Discriminant_Check
8604 (N, Etype (Designated_Type (Typ)));
8607 -- Ada 2005 (AI-363): Require static matching when designated
8608 -- type has discriminants and a constrained partial view, since
8609 -- in general objects of such types are mutable, so we can't
8610 -- allow the access value to designate a constrained object
8611 -- (because access values must be assumed to designate mutable
8612 -- objects when designated type does not impose a constraint).
8614 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8617 elsif Has_Discriminants (Designated_Type (Typ))
8618 and then not Is_Constrained (Des_Btyp)
8620 (Ada_Version < Ada_2005
8622 not Has_Constrained_Partial_View
8623 (Designated_Type (Base_Type (Typ))))
8629 ("object subtype must statically match "
8630 & "designated subtype", P);
8632 if Is_Entity_Name (P)
8633 and then Is_Array_Type (Designated_Type (Typ))
8636 D : constant Node_Id := Declaration_Node (Entity (P));
8639 Error_Msg_N ("aliased object has explicit bounds?",
8641 Error_Msg_N ("\declare without bounds"
8642 & " (and with explicit initialization)?", D);
8643 Error_Msg_N ("\for use with unconstrained access?", D);
8648 -- Check the static accessibility rule of 3.10.2(28).
8649 -- Note that this check is not performed for the
8650 -- case of an anonymous access type, since the access
8651 -- attribute is always legal in such a context.
8653 if Attr_Id /= Attribute_Unchecked_Access
8654 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8655 and then Ekind (Btyp) = E_General_Access_Type
8657 Accessibility_Message;
8662 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
8663 E_Anonymous_Access_Protected_Subprogram_Type)
8665 if Is_Entity_Name (P)
8666 and then not Is_Protected_Type (Scope (Entity (P)))
8668 Error_Msg_F ("context requires a protected subprogram", P);
8670 -- Check accessibility of protected object against that of the
8671 -- access type, but only on user code, because the expander
8672 -- creates access references for handlers. If the context is an
8673 -- anonymous_access_to_protected, there are no accessibility
8674 -- checks either. Omit check entirely for Unrestricted_Access.
8676 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8677 and then Comes_From_Source (N)
8678 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8679 and then Attr_Id /= Attribute_Unrestricted_Access
8681 Accessibility_Message;
8685 elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
8686 E_Anonymous_Access_Subprogram_Type)
8687 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8689 Error_Msg_F ("context requires a non-protected subprogram", P);
8692 -- The context cannot be a pool-specific type, but this is a
8693 -- legality rule, not a resolution rule, so it must be checked
8694 -- separately, after possibly disambiguation (see AI-245).
8696 if Ekind (Btyp) = E_Access_Type
8697 and then Attr_Id /= Attribute_Unrestricted_Access
8699 Wrong_Type (N, Typ);
8702 -- The context may be a constrained access type (however ill-
8703 -- advised such subtypes might be) so in order to generate a
8704 -- constraint check when needed set the type of the attribute
8705 -- reference to the base type of the context.
8707 Set_Etype (N, Btyp);
8709 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8711 if Attr_Id /= Attribute_Unrestricted_Access then
8712 if Is_Atomic_Object (P)
8713 and then not Is_Atomic (Designated_Type (Typ))
8716 ("access to atomic object cannot yield access-to-" &
8717 "non-atomic type", P);
8719 elsif Is_Volatile_Object (P)
8720 and then not Is_Volatile (Designated_Type (Typ))
8723 ("access to volatile object cannot yield access-to-" &
8724 "non-volatile type", P);
8728 if Is_Entity_Name (P) then
8729 Set_Address_Taken (Entity (P));
8731 end Access_Attribute;
8737 -- Deal with resolving the type for Address attribute, overloading
8738 -- is not permitted here, since there is no context to resolve it.
8740 when Attribute_Address | Attribute_Code_Address =>
8741 Address_Attribute : begin
8743 -- To be safe, assume that if the address of a variable is taken,
8744 -- it may be modified via this address, so note modification.
8746 if Is_Variable (P) then
8747 Note_Possible_Modification (P, Sure => False);
8750 if Nkind (P) in N_Subexpr
8751 and then Is_Overloaded (P)
8753 Get_First_Interp (P, Index, It);
8754 Get_Next_Interp (Index, It);
8756 if Present (It.Nam) then
8757 Error_Msg_Name_1 := Aname;
8759 ("prefix of % attribute cannot be overloaded", P);
8763 if not Is_Entity_Name (P)
8764 or else not Is_Overloadable (Entity (P))
8766 if not Is_Task_Type (Etype (P))
8767 or else Nkind (P) = N_Explicit_Dereference
8773 -- If this is the name of a derived subprogram, or that of a
8774 -- generic actual, the address is that of the original entity.
8776 if Is_Entity_Name (P)
8777 and then Is_Overloadable (Entity (P))
8778 and then Present (Alias (Entity (P)))
8781 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8784 if Is_Entity_Name (P) then
8785 Set_Address_Taken (Entity (P));
8788 if Nkind (P) = N_Slice then
8790 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8791 -- even if the array is packed and the slice itself is not
8792 -- addressable. Transform the prefix into an indexed component.
8794 -- Note that the transformation is safe only if we know that
8795 -- the slice is non-null. That is because a null slice can have
8796 -- an out of bounds index value.
8798 -- Right now, gigi blows up if given 'Address on a slice as a
8799 -- result of some incorrect freeze nodes generated by the front
8800 -- end, and this covers up that bug in one case, but the bug is
8801 -- likely still there in the cases not handled by this code ???
8803 -- It's not clear what 'Address *should* return for a null
8804 -- slice with out of bounds indexes, this might be worth an ARG
8807 -- One approach would be to do a length check unconditionally,
8808 -- and then do the transformation below unconditionally, but
8809 -- analyze with checks off, avoiding the problem of the out of
8810 -- bounds index. This approach would interpret the address of
8811 -- an out of bounds null slice as being the address where the
8812 -- array element would be if there was one, which is probably
8813 -- as reasonable an interpretation as any ???
8816 Loc : constant Source_Ptr := Sloc (P);
8817 D : constant Node_Id := Discrete_Range (P);
8821 if Is_Entity_Name (D)
8824 (Type_Low_Bound (Entity (D)),
8825 Type_High_Bound (Entity (D)))
8828 Make_Attribute_Reference (Loc,
8829 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8830 Attribute_Name => Name_First);
8832 elsif Nkind (D) = N_Range
8833 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8835 Lo := Low_Bound (D);
8841 if Present (Lo) then
8843 Make_Indexed_Component (Loc,
8844 Prefix => Relocate_Node (Prefix (P)),
8845 Expressions => New_List (Lo)));
8847 Analyze_And_Resolve (P);
8851 end Address_Attribute;
8857 -- Prefix of the AST_Entry attribute is an entry name which must
8858 -- not be resolved, since this is definitely not an entry call.
8860 when Attribute_AST_Entry =>
8867 -- Prefix of Body_Version attribute can be a subprogram name which
8868 -- must not be resolved, since this is not a call.
8870 when Attribute_Body_Version =>
8877 -- Prefix of Caller attribute is an entry name which must not
8878 -- be resolved, since this is definitely not an entry call.
8880 when Attribute_Caller =>
8887 -- Shares processing with Address attribute
8893 -- If the prefix of the Count attribute is an entry name it must not
8894 -- be resolved, since this is definitely not an entry call. However,
8895 -- if it is an element of an entry family, the index itself may
8896 -- have to be resolved because it can be a general expression.
8898 when Attribute_Count =>
8899 if Nkind (P) = N_Indexed_Component
8900 and then Is_Entity_Name (Prefix (P))
8903 Indx : constant Node_Id := First (Expressions (P));
8904 Fam : constant Entity_Id := Entity (Prefix (P));
8906 Resolve (Indx, Entry_Index_Type (Fam));
8907 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8915 -- Prefix of the Elaborated attribute is a subprogram name which
8916 -- must not be resolved, since this is definitely not a call. Note
8917 -- that it is a library unit, so it cannot be overloaded here.
8919 when Attribute_Elaborated =>
8926 -- Prefix of Enabled attribute is a check name, which must be treated
8927 -- specially and not touched by Resolve.
8929 when Attribute_Enabled =>
8932 --------------------
8933 -- Mechanism_Code --
8934 --------------------
8936 -- Prefix of the Mechanism_Code attribute is a function name
8937 -- which must not be resolved. Should we check for overloaded ???
8939 when Attribute_Mechanism_Code =>
8946 -- Most processing is done in sem_dist, after determining the
8947 -- context type. Node is rewritten as a conversion to a runtime call.
8949 when Attribute_Partition_ID =>
8950 Process_Partition_Id (N);
8957 when Attribute_Pool_Address =>
8964 -- We replace the Range attribute node with a range expression whose
8965 -- bounds are the 'First and 'Last attributes applied to the same
8966 -- prefix. The reason that we do this transformation here instead of
8967 -- in the expander is that it simplifies other parts of the semantic
8968 -- analysis which assume that the Range has been replaced; thus it
8969 -- must be done even when in semantic-only mode (note that the RM
8970 -- specifically mentions this equivalence, we take care that the
8971 -- prefix is only evaluated once).
8973 when Attribute_Range => Range_Attribute :
8980 if not Is_Entity_Name (P)
8981 or else not Is_Type (Entity (P))
8986 Dims := Expressions (N);
8989 Make_Attribute_Reference (Loc,
8991 Duplicate_Subexpr (P, Name_Req => True),
8992 Attribute_Name => Name_Last,
8993 Expressions => Dims);
8996 Make_Attribute_Reference (Loc,
8998 Attribute_Name => Name_First,
8999 Expressions => (Dims));
9001 -- Do not share the dimension indicator, if present. Even
9002 -- though it is a static constant, its source location
9003 -- may be modified when printing expanded code and node
9004 -- sharing will lead to chaos in Sprint.
9006 if Present (Dims) then
9007 Set_Expressions (LB,
9008 New_List (New_Copy_Tree (First (Dims))));
9011 -- If the original was marked as Must_Not_Freeze (see code
9012 -- in Sem_Ch3.Make_Index), then make sure the rewriting
9013 -- does not freeze either.
9015 if Must_Not_Freeze (N) then
9016 Set_Must_Not_Freeze (HB);
9017 Set_Must_Not_Freeze (LB);
9018 Set_Must_Not_Freeze (Prefix (HB));
9019 Set_Must_Not_Freeze (Prefix (LB));
9022 if Raises_Constraint_Error (Prefix (N)) then
9024 -- Preserve Sloc of prefix in the new bounds, so that
9025 -- the posted warning can be removed if we are within
9026 -- unreachable code.
9028 Set_Sloc (LB, Sloc (Prefix (N)));
9029 Set_Sloc (HB, Sloc (Prefix (N)));
9032 Rewrite (N, Make_Range (Loc, LB, HB));
9033 Analyze_And_Resolve (N, Typ);
9035 -- Ensure that the expanded range does not have side effects
9037 Force_Evaluation (LB);
9038 Force_Evaluation (HB);
9040 -- Normally after resolving attribute nodes, Eval_Attribute
9041 -- is called to do any possible static evaluation of the node.
9042 -- However, here since the Range attribute has just been
9043 -- transformed into a range expression it is no longer an
9044 -- attribute node and therefore the call needs to be avoided
9045 -- and is accomplished by simply returning from the procedure.
9048 end Range_Attribute;
9054 -- We will only come here during the prescan of a spec expression
9055 -- containing a Result attribute. In that case the proper Etype has
9056 -- already been set, and nothing more needs to be done here.
9058 when Attribute_Result =>
9065 -- Prefix must not be resolved in this case, since it is not a
9066 -- real entity reference. No action of any kind is require!
9068 when Attribute_UET_Address =>
9071 ----------------------
9072 -- Unchecked_Access --
9073 ----------------------
9075 -- Processing is shared with Access
9077 -------------------------
9078 -- Unrestricted_Access --
9079 -------------------------
9081 -- Processing is shared with Access
9087 -- Apply range check. Note that we did not do this during the
9088 -- analysis phase, since we wanted Eval_Attribute to have a
9089 -- chance at finding an illegal out of range value.
9091 when Attribute_Val =>
9093 -- Note that we do our own Eval_Attribute call here rather than
9094 -- use the common one, because we need to do processing after
9095 -- the call, as per above comment.
9099 -- Eval_Attribute may replace the node with a raise CE, or
9100 -- fold it to a constant. Obviously we only apply a scalar
9101 -- range check if this did not happen!
9103 if Nkind (N) = N_Attribute_Reference
9104 and then Attribute_Name (N) = Name_Val
9106 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
9115 -- Prefix of Version attribute can be a subprogram name which
9116 -- must not be resolved, since this is not a call.
9118 when Attribute_Version =>
9121 ----------------------
9122 -- Other Attributes --
9123 ----------------------
9125 -- For other attributes, resolve prefix unless it is a type. If
9126 -- the attribute reference itself is a type name ('Base and 'Class)
9127 -- then this is only legal within a task or protected record.
9130 if not Is_Entity_Name (P)
9131 or else not Is_Type (Entity (P))
9136 -- If the attribute reference itself is a type name ('Base,
9137 -- 'Class) then this is only legal within a task or protected
9138 -- record. What is this all about ???
9140 if Is_Entity_Name (N)
9141 and then Is_Type (Entity (N))
9143 if Is_Concurrent_Type (Entity (N))
9144 and then In_Open_Scopes (Entity (P))
9149 ("invalid use of subtype name in expression or call", N);
9153 -- For attributes whose argument may be a string, complete
9154 -- resolution of argument now. This avoids premature expansion
9155 -- (and the creation of transient scopes) before the attribute
9156 -- reference is resolved.
9159 when Attribute_Value =>
9160 Resolve (First (Expressions (N)), Standard_String);
9162 when Attribute_Wide_Value =>
9163 Resolve (First (Expressions (N)), Standard_Wide_String);
9165 when Attribute_Wide_Wide_Value =>
9166 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
9168 when others => null;
9171 -- If the prefix of the attribute is a class-wide type then it
9172 -- will be expanded into a dispatching call to a predefined
9173 -- primitive. Therefore we must check for potential violation
9174 -- of such restriction.
9176 if Is_Class_Wide_Type (Etype (P)) then
9177 Check_Restriction (No_Dispatching_Calls, N);
9181 -- Normally the Freezing is done by Resolve but sometimes the Prefix
9182 -- is not resolved, in which case the freezing must be done now.
9184 Freeze_Expression (P);
9186 -- Finally perform static evaluation on the attribute reference
9189 end Resolve_Attribute;
9191 --------------------------------
9192 -- Stream_Attribute_Available --
9193 --------------------------------
9195 function Stream_Attribute_Available
9197 Nam : TSS_Name_Type;
9198 Partial_View : Node_Id := Empty) return Boolean
9200 Etyp : Entity_Id := Typ;
9202 -- Start of processing for Stream_Attribute_Available
9205 -- We need some comments in this body ???
9207 if Has_Stream_Attribute_Definition (Typ, Nam) then
9211 if Is_Class_Wide_Type (Typ) then
9212 return not Is_Limited_Type (Typ)
9213 or else Stream_Attribute_Available (Etype (Typ), Nam);
9216 if Nam = TSS_Stream_Input
9217 and then Is_Abstract_Type (Typ)
9218 and then not Is_Class_Wide_Type (Typ)
9223 if not (Is_Limited_Type (Typ)
9224 or else (Present (Partial_View)
9225 and then Is_Limited_Type (Partial_View)))
9230 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
9232 if Nam = TSS_Stream_Input
9233 and then Ada_Version >= Ada_2005
9234 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
9238 elsif Nam = TSS_Stream_Output
9239 and then Ada_Version >= Ada_2005
9240 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
9245 -- Case of Read and Write: check for attribute definition clause that
9246 -- applies to an ancestor type.
9248 while Etype (Etyp) /= Etyp loop
9249 Etyp := Etype (Etyp);
9251 if Has_Stream_Attribute_Definition (Etyp, Nam) then
9256 if Ada_Version < Ada_2005 then
9258 -- In Ada 95 mode, also consider a non-visible definition
9261 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
9264 and then Stream_Attribute_Available
9265 (Btyp, Nam, Partial_View => Typ);
9270 end Stream_Attribute_Available;