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.
268 procedure Check_Fixed_Point_Type;
269 -- Verify that prefix of attribute N is a fixed type
271 procedure Check_Fixed_Point_Type_0;
272 -- Verify that prefix of attribute N is a fixed type and that
273 -- no attribute expressions are present
275 procedure Check_Floating_Point_Type;
276 -- Verify that prefix of attribute N is a float type
278 procedure Check_Floating_Point_Type_0;
279 -- Verify that prefix of attribute N is a float type and that
280 -- no attribute expressions are present
282 procedure Check_Floating_Point_Type_1;
283 -- Verify that prefix of attribute N is a float type and that
284 -- exactly one attribute expression is present
286 procedure Check_Floating_Point_Type_2;
287 -- Verify that prefix of attribute N is a float type and that
288 -- two attribute expressions are present
290 procedure Legal_Formal_Attribute;
291 -- Common processing for attributes Definite and Has_Discriminants.
292 -- Checks that prefix is generic indefinite formal type.
294 procedure Check_SPARK_Restriction_On_Attribute;
295 -- Issue an error in formal mode because attribute N is allowed
297 procedure Check_Integer_Type;
298 -- Verify that prefix of attribute N is an integer type
300 procedure Check_Modular_Integer_Type;
301 -- Verify that prefix of attribute N is a modular integer type
303 procedure Check_Not_CPP_Type;
304 -- Check that P (the prefix of the attribute) is not an CPP type
305 -- for which no Ada predefined primitive is available.
307 procedure Check_Not_Incomplete_Type;
308 -- Check that P (the prefix of the attribute) is not an incomplete
309 -- type or a private type for which no full view has been given.
311 procedure Check_Object_Reference (P : Node_Id);
312 -- Check that P (the prefix of the attribute) is an object reference
314 procedure Check_Program_Unit;
315 -- Verify that prefix of attribute N is a program unit
317 procedure Check_Real_Type;
318 -- Verify that prefix of attribute N is fixed or float type
320 procedure Check_Scalar_Type;
321 -- Verify that prefix of attribute N is a scalar type
323 procedure Check_Standard_Prefix;
324 -- Verify that prefix of attribute N is package Standard
326 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
327 -- Validity checking for stream attribute. Nam is the TSS name of the
328 -- corresponding possible defined attribute function (e.g. for the
329 -- Read attribute, Nam will be TSS_Stream_Read).
331 procedure Check_PolyORB_Attribute;
332 -- Validity checking for PolyORB/DSA attribute
334 procedure Check_Task_Prefix;
335 -- Verify that prefix of attribute N is a task or task type
337 procedure Check_Type;
338 -- Verify that the prefix of attribute N is a type
340 procedure Check_Unit_Name (Nod : Node_Id);
341 -- Check that Nod is of the form of a library unit name, i.e that
342 -- it is an identifier, or a selected component whose prefix is
343 -- itself of the form of a library unit name. Note that this is
344 -- quite different from Check_Program_Unit, since it only checks
345 -- the syntactic form of the name, not the semantic identity. This
346 -- is because it is used with attributes (Elab_Body, Elab_Spec,
347 -- UET_Address and Elaborated) which can refer to non-visible unit.
349 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
350 pragma No_Return (Error_Attr);
351 procedure Error_Attr;
352 pragma No_Return (Error_Attr);
353 -- Posts error using Error_Msg_N at given node, sets type of attribute
354 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
355 -- semantic processing. The message typically contains a % insertion
356 -- character which is replaced by the attribute name. The call with
357 -- no arguments is used when the caller has already generated the
358 -- required error messages.
360 procedure Error_Attr_P (Msg : String);
361 pragma No_Return (Error_Attr);
362 -- Like Error_Attr, but error is posted at the start of the prefix
364 procedure Standard_Attribute (Val : Int);
365 -- Used to process attributes whose prefix is package Standard which
366 -- yield values of type Universal_Integer. The attribute reference
367 -- node is rewritten with an integer literal of the given value.
369 procedure Unexpected_Argument (En : Node_Id);
370 -- Signal unexpected attribute argument (En is the argument)
372 procedure Validate_Non_Static_Attribute_Function_Call;
373 -- Called when processing an attribute that is a function call to a
374 -- non-static function, i.e. an attribute function that either takes
375 -- non-scalar arguments or returns a non-scalar result. Verifies that
376 -- such a call does not appear in a preelaborable context.
378 ------------------------------
379 -- Analyze_Access_Attribute --
380 ------------------------------
382 procedure Analyze_Access_Attribute is
383 Acc_Type : Entity_Id;
388 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
389 -- Build an access-to-object type whose designated type is DT,
390 -- and whose Ekind is appropriate to the attribute type. The
391 -- type that is constructed is returned as the result.
393 procedure Build_Access_Subprogram_Type (P : Node_Id);
394 -- Build an access to subprogram whose designated type is the type of
395 -- the prefix. If prefix is overloaded, so is the node itself. The
396 -- result is stored in Acc_Type.
398 function OK_Self_Reference return Boolean;
399 -- An access reference whose prefix is a type can legally appear
400 -- within an aggregate, where it is obtained by expansion of
401 -- a defaulted aggregate. The enclosing aggregate that contains
402 -- the self-referenced is flagged so that the self-reference can
403 -- be expanded into a reference to the target object (see exp_aggr).
405 ------------------------------
406 -- Build_Access_Object_Type --
407 ------------------------------
409 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
410 Typ : constant Entity_Id :=
412 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
414 Set_Etype (Typ, Typ);
416 Set_Associated_Node_For_Itype (Typ, N);
417 Set_Directly_Designated_Type (Typ, DT);
419 end Build_Access_Object_Type;
421 ----------------------------------
422 -- Build_Access_Subprogram_Type --
423 ----------------------------------
425 procedure Build_Access_Subprogram_Type (P : Node_Id) is
426 Index : Interp_Index;
429 procedure Check_Local_Access (E : Entity_Id);
430 -- Deal with possible access to local subprogram. If we have such
431 -- an access, we set a flag to kill all tracked values on any call
432 -- because this access value may be passed around, and any called
433 -- code might use it to access a local procedure which clobbers a
434 -- tracked value. If the scope is a loop or block, indicate that
435 -- value tracking is disabled for the enclosing subprogram.
437 function Get_Kind (E : Entity_Id) return Entity_Kind;
438 -- Distinguish between access to regular/protected subprograms
440 ------------------------
441 -- Check_Local_Access --
442 ------------------------
444 procedure Check_Local_Access (E : Entity_Id) is
446 if not Is_Library_Level_Entity (E) then
447 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
448 Set_Suppress_Value_Tracking_On_Call
449 (Nearest_Dynamic_Scope (Current_Scope));
451 end Check_Local_Access;
457 function Get_Kind (E : Entity_Id) return Entity_Kind is
459 if Convention (E) = Convention_Protected then
460 return E_Access_Protected_Subprogram_Type;
462 return E_Access_Subprogram_Type;
466 -- Start of processing for Build_Access_Subprogram_Type
469 -- In the case of an access to subprogram, use the name of the
470 -- subprogram itself as the designated type. Type-checking in
471 -- this case compares the signatures of the designated types.
473 -- Note: This fragment of the tree is temporarily malformed
474 -- because the correct tree requires an E_Subprogram_Type entity
475 -- as the designated type. In most cases this designated type is
476 -- later overridden by the semantics with the type imposed by the
477 -- context during the resolution phase. In the specific case of
478 -- the expression Address!(Prim'Unrestricted_Access), used to
479 -- initialize slots of dispatch tables, this work will be done by
480 -- the expander (see Exp_Aggr).
482 -- The reason to temporarily add this kind of node to the tree
483 -- instead of a proper E_Subprogram_Type itype, is the following:
484 -- in case of errors found in the source file we report better
485 -- error messages. For example, instead of generating the
488 -- "expected access to subprogram with profile
489 -- defined at line X"
491 -- we currently generate:
493 -- "expected access to function Z defined at line X"
495 Set_Etype (N, Any_Type);
497 if not Is_Overloaded (P) then
498 Check_Local_Access (Entity (P));
500 if not Is_Intrinsic_Subprogram (Entity (P)) then
501 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
502 Set_Is_Public (Acc_Type, False);
503 Set_Etype (Acc_Type, Acc_Type);
504 Set_Convention (Acc_Type, Convention (Entity (P)));
505 Set_Directly_Designated_Type (Acc_Type, Entity (P));
506 Set_Etype (N, Acc_Type);
507 Freeze_Before (N, Acc_Type);
511 Get_First_Interp (P, Index, It);
512 while Present (It.Nam) loop
513 Check_Local_Access (It.Nam);
515 if not Is_Intrinsic_Subprogram (It.Nam) then
516 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
517 Set_Is_Public (Acc_Type, False);
518 Set_Etype (Acc_Type, Acc_Type);
519 Set_Convention (Acc_Type, Convention (It.Nam));
520 Set_Directly_Designated_Type (Acc_Type, It.Nam);
521 Add_One_Interp (N, Acc_Type, Acc_Type);
522 Freeze_Before (N, Acc_Type);
525 Get_Next_Interp (Index, It);
529 -- Cannot be applied to intrinsic. Looking at the tests above,
530 -- the only way Etype (N) can still be set to Any_Type is if
531 -- Is_Intrinsic_Subprogram was True for some referenced entity.
533 if Etype (N) = Any_Type then
534 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
536 end Build_Access_Subprogram_Type;
538 ----------------------
539 -- OK_Self_Reference --
540 ----------------------
542 function OK_Self_Reference return Boolean is
549 (Nkind (Par) = N_Component_Association
550 or else Nkind (Par) in N_Subexpr)
552 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
553 if Etype (Par) = Typ then
554 Set_Has_Self_Reference (Par);
562 -- No enclosing aggregate, or not a self-reference
565 end OK_Self_Reference;
567 -- Start of processing for Analyze_Access_Attribute
570 Check_SPARK_Restriction_On_Attribute;
573 if Nkind (P) = N_Character_Literal then
575 ("prefix of % attribute cannot be enumeration literal");
578 -- Case of access to subprogram
580 if Is_Entity_Name (P)
581 and then Is_Overloadable (Entity (P))
583 if Has_Pragma_Inline_Always (Entity (P)) then
585 ("prefix of % attribute cannot be Inline_Always subprogram");
588 if Aname = Name_Unchecked_Access then
589 Error_Attr ("attribute% cannot be applied to a subprogram", P);
592 -- Issue an error if the prefix denotes an eliminated subprogram
594 Check_For_Eliminated_Subprogram (P, Entity (P));
596 -- Check for obsolescent subprogram reference
598 Check_Obsolescent_2005_Entity (Entity (P), P);
600 -- Build the appropriate subprogram type
602 Build_Access_Subprogram_Type (P);
604 -- For unrestricted access, kill current values, since this
605 -- attribute allows a reference to a local subprogram that
606 -- could modify local variables to be passed out of scope
608 if Aname = Name_Unrestricted_Access then
610 -- Do not kill values on nodes initializing dispatch tables
611 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
612 -- is currently generated by the expander only for this
613 -- purpose. Done to keep the quality of warnings currently
614 -- generated by the compiler (otherwise any declaration of
615 -- a tagged type cleans constant indications from its scope).
617 if Nkind (Parent (N)) = N_Unchecked_Type_Conversion
618 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
620 Etype (Parent (N)) = RTE (RE_Size_Ptr))
621 and then Is_Dispatching_Operation
622 (Directly_Designated_Type (Etype (N)))
632 -- Component is an operation of a protected type
634 elsif Nkind (P) = N_Selected_Component
635 and then Is_Overloadable (Entity (Selector_Name (P)))
637 if Ekind (Entity (Selector_Name (P))) = E_Entry then
638 Error_Attr_P ("prefix of % attribute must be subprogram");
641 Build_Access_Subprogram_Type (Selector_Name (P));
645 -- Deal with incorrect reference to a type, but note that some
646 -- accesses are allowed: references to the current type instance,
647 -- or in Ada 2005 self-referential pointer in a default-initialized
650 if Is_Entity_Name (P) then
653 -- The reference may appear in an aggregate that has been expanded
654 -- into a loop. Locate scope of type definition, if any.
656 Scop := Current_Scope;
657 while Ekind (Scop) = E_Loop loop
658 Scop := Scope (Scop);
661 if Is_Type (Typ) then
663 -- OK if we are within the scope of a limited type
664 -- let's mark the component as having per object constraint
666 if Is_Anonymous_Tagged_Base (Scop, Typ) then
674 Q : Node_Id := Parent (N);
678 and then Nkind (Q) /= N_Component_Declaration
684 Set_Has_Per_Object_Constraint
685 (Defining_Identifier (Q), True);
689 if Nkind (P) = N_Expanded_Name then
691 ("current instance prefix must be a direct name", P);
694 -- If a current instance attribute appears in a component
695 -- constraint it must appear alone; other contexts (spec-
696 -- expressions, within a task body) are not subject to this
699 if not In_Spec_Expression
700 and then not Has_Completion (Scop)
702 Nkind_In (Parent (N), N_Discriminant_Association,
703 N_Index_Or_Discriminant_Constraint)
706 ("current instance attribute must appear alone", N);
709 if Is_CPP_Class (Root_Type (Typ)) then
711 ("?current instance unsupported for derivations of "
712 & "'C'P'P types", N);
715 -- OK if we are in initialization procedure for the type
716 -- in question, in which case the reference to the type
717 -- is rewritten as a reference to the current object.
719 elsif Ekind (Scop) = E_Procedure
720 and then Is_Init_Proc (Scop)
721 and then Etype (First_Formal (Scop)) = Typ
724 Make_Attribute_Reference (Loc,
725 Prefix => Make_Identifier (Loc, Name_uInit),
726 Attribute_Name => Name_Unrestricted_Access));
730 -- OK if a task type, this test needs sharpening up ???
732 elsif Is_Task_Type (Typ) then
735 -- OK if self-reference in an aggregate in Ada 2005, and
736 -- the reference comes from a copied default expression.
738 -- Note that we check legality of self-reference even if the
739 -- expression comes from source, e.g. when a single component
740 -- association in an aggregate has a box association.
742 elsif Ada_Version >= Ada_2005
743 and then OK_Self_Reference
747 -- OK if reference to current instance of a protected object
749 elsif Is_Protected_Self_Reference (P) then
752 -- Otherwise we have an error case
755 Error_Attr ("% attribute cannot be applied to type", P);
761 -- If we fall through, we have a normal access to object case.
762 -- Unrestricted_Access is legal wherever an allocator would be
763 -- legal, so its Etype is set to E_Allocator. The expected type
764 -- of the other attributes is a general access type, and therefore
765 -- we label them with E_Access_Attribute_Type.
767 if not Is_Overloaded (P) then
768 Acc_Type := Build_Access_Object_Type (P_Type);
769 Set_Etype (N, Acc_Type);
772 Index : Interp_Index;
775 Set_Etype (N, Any_Type);
776 Get_First_Interp (P, Index, It);
777 while Present (It.Typ) loop
778 Acc_Type := Build_Access_Object_Type (It.Typ);
779 Add_One_Interp (N, Acc_Type, Acc_Type);
780 Get_Next_Interp (Index, It);
785 -- Special cases when we can find a prefix that is an entity name
794 if Is_Entity_Name (PP) then
797 -- If we have an access to an object, and the attribute
798 -- comes from source, then set the object as potentially
799 -- source modified. We do this because the resulting access
800 -- pointer can be used to modify the variable, and we might
801 -- not detect this, leading to some junk warnings.
803 Set_Never_Set_In_Source (Ent, False);
805 -- Mark entity as address taken, and kill current values
807 Set_Address_Taken (Ent);
808 Kill_Current_Values (Ent);
811 elsif Nkind_In (PP, N_Selected_Component,
822 -- Check for aliased view unless unrestricted case. We allow a
823 -- nonaliased prefix when within an instance because the prefix may
824 -- have been a tagged formal object, which is defined to be aliased
825 -- even when the actual might not be (other instance cases will have
826 -- been caught in the generic). Similarly, within an inlined body we
827 -- know that the attribute is legal in the original subprogram, and
828 -- therefore legal in the expansion.
830 if Aname /= Name_Unrestricted_Access
831 and then not Is_Aliased_View (P)
832 and then not In_Instance
833 and then not In_Inlined_Body
835 Error_Attr_P ("prefix of % attribute must be aliased");
837 end Analyze_Access_Attribute;
839 ---------------------------------
840 -- Bad_Attribute_For_Predicate --
841 ---------------------------------
843 procedure Bad_Attribute_For_Predicate is
845 if Is_Scalar_Type (P_Type)
846 and then Comes_From_Source (N)
848 Error_Msg_Name_1 := Aname;
849 Bad_Predicated_Subtype_Use
850 ("type& has predicates, attribute % not allowed", N, P_Type);
852 end Bad_Attribute_For_Predicate;
854 --------------------------------
855 -- Check_Array_Or_Scalar_Type --
856 --------------------------------
858 procedure Check_Array_Or_Scalar_Type is
862 -- Dimension number for array attributes
865 -- Case of string literal or string literal subtype. These cases
866 -- cannot arise from legal Ada code, but the expander is allowed
867 -- to generate them. They require special handling because string
868 -- literal subtypes do not have standard bounds (the whole idea
869 -- of these subtypes is to avoid having to generate the bounds)
871 if Ekind (P_Type) = E_String_Literal_Subtype then
872 Set_Etype (N, Etype (First_Index (P_Base_Type)));
877 elsif Is_Scalar_Type (P_Type) then
881 Error_Attr ("invalid argument in % attribute", E1);
883 Set_Etype (N, P_Base_Type);
887 -- The following is a special test to allow 'First to apply to
888 -- private scalar types if the attribute comes from generated
889 -- code. This occurs in the case of Normalize_Scalars code.
891 elsif Is_Private_Type (P_Type)
892 and then Present (Full_View (P_Type))
893 and then Is_Scalar_Type (Full_View (P_Type))
894 and then not Comes_From_Source (N)
896 Set_Etype (N, Implementation_Base_Type (P_Type));
898 -- Array types other than string literal subtypes handled above
903 -- We know prefix is an array type, or the name of an array
904 -- object, and that the expression, if present, is static
905 -- and within the range of the dimensions of the type.
907 pragma Assert (Is_Array_Type (P_Type));
908 Index := First_Index (P_Base_Type);
912 -- First dimension assumed
914 Set_Etype (N, Base_Type (Etype (Index)));
917 D := UI_To_Int (Intval (E1));
919 for J in 1 .. D - 1 loop
923 Set_Etype (N, Base_Type (Etype (Index)));
924 Set_Etype (E1, Standard_Integer);
927 end Check_Array_Or_Scalar_Type;
929 ----------------------
930 -- Check_Array_Type --
931 ----------------------
933 procedure Check_Array_Type is
935 -- Dimension number for array attributes
938 -- If the type is a string literal type, then this must be generated
939 -- internally, and no further check is required on its legality.
941 if Ekind (P_Type) = E_String_Literal_Subtype then
944 -- If the type is a composite, it is an illegal aggregate, no point
947 elsif P_Type = Any_Composite then
951 -- Normal case of array type or subtype
953 Check_Either_E0_Or_E1;
956 if Is_Array_Type (P_Type) then
957 if not Is_Constrained (P_Type)
958 and then Is_Entity_Name (P)
959 and then Is_Type (Entity (P))
961 -- Note: we do not call Error_Attr here, since we prefer to
962 -- continue, using the relevant index type of the array,
963 -- even though it is unconstrained. This gives better error
964 -- recovery behavior.
966 Error_Msg_Name_1 := Aname;
968 ("prefix for % attribute must be constrained array", P);
971 D := Number_Dimensions (P_Type);
974 if Is_Private_Type (P_Type) then
975 Error_Attr_P ("prefix for % attribute may not be private type");
977 elsif Is_Access_Type (P_Type)
978 and then Is_Array_Type (Designated_Type (P_Type))
979 and then Is_Entity_Name (P)
980 and then Is_Type (Entity (P))
982 Error_Attr_P ("prefix of % attribute cannot be access type");
984 elsif Attr_Id = Attribute_First
986 Attr_Id = Attribute_Last
988 Error_Attr ("invalid prefix for % attribute", P);
991 Error_Attr_P ("prefix for % attribute must be array");
996 Resolve (E1, Any_Integer);
997 Set_Etype (E1, Standard_Integer);
999 if not Is_Static_Expression (E1)
1000 or else Raises_Constraint_Error (E1)
1002 Flag_Non_Static_Expr
1003 ("expression for dimension must be static!", E1);
1006 elsif UI_To_Int (Expr_Value (E1)) > D
1007 or else UI_To_Int (Expr_Value (E1)) < 1
1009 Error_Attr ("invalid dimension number for array type", E1);
1013 if (Style_Check and Style_Check_Array_Attribute_Index)
1014 and then Comes_From_Source (N)
1016 Style.Check_Array_Attribute_Index (N, E1, D);
1018 end Check_Array_Type;
1020 -------------------------
1021 -- Check_Asm_Attribute --
1022 -------------------------
1024 procedure Check_Asm_Attribute is
1029 -- Check first argument is static string expression
1031 Analyze_And_Resolve (E1, Standard_String);
1033 if Etype (E1) = Any_Type then
1036 elsif not Is_OK_Static_Expression (E1) then
1037 Flag_Non_Static_Expr
1038 ("constraint argument must be static string expression!", E1);
1042 -- Check second argument is right type
1044 Analyze_And_Resolve (E2, Entity (P));
1046 -- Note: that is all we need to do, we don't need to check
1047 -- that it appears in a correct context. The Ada type system
1048 -- will do that for us.
1050 end Check_Asm_Attribute;
1052 ---------------------
1053 -- Check_Component --
1054 ---------------------
1056 procedure Check_Component is
1060 if Nkind (P) /= N_Selected_Component
1062 (Ekind (Entity (Selector_Name (P))) /= E_Component
1064 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1066 Error_Attr_P ("prefix for % attribute must be selected component");
1068 end Check_Component;
1070 ------------------------------------
1071 -- Check_Decimal_Fixed_Point_Type --
1072 ------------------------------------
1074 procedure Check_Decimal_Fixed_Point_Type is
1078 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1079 Error_Attr_P ("prefix of % attribute must be decimal type");
1081 end Check_Decimal_Fixed_Point_Type;
1083 -----------------------
1084 -- Check_Dereference --
1085 -----------------------
1087 procedure Check_Dereference is
1090 -- Case of a subtype mark
1092 if Is_Entity_Name (P)
1093 and then Is_Type (Entity (P))
1098 -- Case of an expression
1102 if Is_Access_Type (P_Type) then
1104 -- If there is an implicit dereference, then we must freeze
1105 -- the designated type of the access type, since the type of
1106 -- the referenced array is this type (see AI95-00106).
1108 -- As done elsewhere, freezing must not happen when pre-analyzing
1109 -- a pre- or postcondition or a default value for an object or
1110 -- for a formal parameter.
1112 if not In_Spec_Expression then
1113 Freeze_Before (N, Designated_Type (P_Type));
1117 Make_Explicit_Dereference (Sloc (P),
1118 Prefix => Relocate_Node (P)));
1120 Analyze_And_Resolve (P);
1121 P_Type := Etype (P);
1123 if P_Type = Any_Type then
1124 raise Bad_Attribute;
1127 P_Base_Type := Base_Type (P_Type);
1129 end Check_Dereference;
1131 -------------------------
1132 -- Check_Discrete_Type --
1133 -------------------------
1135 procedure Check_Discrete_Type is
1139 if not Is_Discrete_Type (P_Type) then
1140 Error_Attr_P ("prefix of % attribute must be discrete type");
1142 end Check_Discrete_Type;
1148 procedure Check_E0 is
1150 if Present (E1) then
1151 Unexpected_Argument (E1);
1159 procedure Check_E1 is
1161 Check_Either_E0_Or_E1;
1165 -- Special-case attributes that are functions and that appear as
1166 -- the prefix of another attribute. Error is posted on parent.
1168 if Nkind (Parent (N)) = N_Attribute_Reference
1169 and then (Attribute_Name (Parent (N)) = Name_Address
1171 Attribute_Name (Parent (N)) = Name_Code_Address
1173 Attribute_Name (Parent (N)) = Name_Access)
1175 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1176 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1177 Set_Etype (Parent (N), Any_Type);
1178 Set_Entity (Parent (N), Any_Type);
1179 raise Bad_Attribute;
1182 Error_Attr ("missing argument for % attribute", N);
1191 procedure Check_E2 is
1194 Error_Attr ("missing arguments for % attribute (2 required)", N);
1196 Error_Attr ("missing argument for % attribute (2 required)", N);
1200 ---------------------------
1201 -- Check_Either_E0_Or_E1 --
1202 ---------------------------
1204 procedure Check_Either_E0_Or_E1 is
1206 if Present (E2) then
1207 Unexpected_Argument (E2);
1209 end Check_Either_E0_Or_E1;
1211 ----------------------
1212 -- Check_Enum_Image --
1213 ----------------------
1215 procedure Check_Enum_Image is
1218 if Is_Enumeration_Type (P_Base_Type) then
1219 Lit := First_Literal (P_Base_Type);
1220 while Present (Lit) loop
1221 Set_Referenced (Lit);
1225 end Check_Enum_Image;
1227 ----------------------------
1228 -- Check_Fixed_Point_Type --
1229 ----------------------------
1231 procedure Check_Fixed_Point_Type is
1235 if not Is_Fixed_Point_Type (P_Type) then
1236 Error_Attr_P ("prefix of % attribute must be fixed point type");
1238 end Check_Fixed_Point_Type;
1240 ------------------------------
1241 -- Check_Fixed_Point_Type_0 --
1242 ------------------------------
1244 procedure Check_Fixed_Point_Type_0 is
1246 Check_Fixed_Point_Type;
1248 end Check_Fixed_Point_Type_0;
1250 -------------------------------
1251 -- Check_Floating_Point_Type --
1252 -------------------------------
1254 procedure Check_Floating_Point_Type is
1258 if not Is_Floating_Point_Type (P_Type) then
1259 Error_Attr_P ("prefix of % attribute must be float type");
1261 end Check_Floating_Point_Type;
1263 ---------------------------------
1264 -- Check_Floating_Point_Type_0 --
1265 ---------------------------------
1267 procedure Check_Floating_Point_Type_0 is
1269 Check_Floating_Point_Type;
1271 end Check_Floating_Point_Type_0;
1273 ---------------------------------
1274 -- Check_Floating_Point_Type_1 --
1275 ---------------------------------
1277 procedure Check_Floating_Point_Type_1 is
1279 Check_Floating_Point_Type;
1281 end Check_Floating_Point_Type_1;
1283 ---------------------------------
1284 -- Check_Floating_Point_Type_2 --
1285 ---------------------------------
1287 procedure Check_Floating_Point_Type_2 is
1289 Check_Floating_Point_Type;
1291 end Check_Floating_Point_Type_2;
1293 ------------------------
1294 -- Check_Integer_Type --
1295 ------------------------
1297 procedure Check_Integer_Type is
1301 if not Is_Integer_Type (P_Type) then
1302 Error_Attr_P ("prefix of % attribute must be integer type");
1304 end Check_Integer_Type;
1306 --------------------------------
1307 -- Check_Modular_Integer_Type --
1308 --------------------------------
1310 procedure Check_Modular_Integer_Type is
1314 if not Is_Modular_Integer_Type (P_Type) then
1316 ("prefix of % attribute must be modular integer type");
1318 end Check_Modular_Integer_Type;
1320 ------------------------
1321 -- Check_Not_CPP_Type --
1322 ------------------------
1324 procedure Check_Not_CPP_Type is
1326 if Is_Tagged_Type (Etype (P))
1327 and then Convention (Etype (P)) = Convention_CPP
1328 and then Is_CPP_Class (Root_Type (Etype (P)))
1331 ("invalid use of % attribute with 'C'P'P tagged type");
1333 end Check_Not_CPP_Type;
1335 -------------------------------
1336 -- Check_Not_Incomplete_Type --
1337 -------------------------------
1339 procedure Check_Not_Incomplete_Type is
1344 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1345 -- dereference we have to check wrong uses of incomplete types
1346 -- (other wrong uses are checked at their freezing point).
1348 -- Example 1: Limited-with
1350 -- limited with Pkg;
1352 -- type Acc is access Pkg.T;
1354 -- S : Integer := X.all'Size; -- ERROR
1357 -- Example 2: Tagged incomplete
1359 -- type T is tagged;
1360 -- type Acc is access all T;
1362 -- S : constant Integer := X.all'Size; -- ERROR
1363 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1365 if Ada_Version >= Ada_2005
1366 and then Nkind (P) = N_Explicit_Dereference
1369 while Nkind (E) = N_Explicit_Dereference loop
1375 if From_With_Type (Typ) then
1377 ("prefix of % attribute cannot be an incomplete type");
1380 if Is_Access_Type (Typ) then
1381 Typ := Directly_Designated_Type (Typ);
1384 if Is_Class_Wide_Type (Typ) then
1385 Typ := Root_Type (Typ);
1388 -- A legal use of a shadow entity occurs only when the unit
1389 -- where the non-limited view resides is imported via a regular
1390 -- with clause in the current body. Such references to shadow
1391 -- entities may occur in subprogram formals.
1393 if Is_Incomplete_Type (Typ)
1394 and then From_With_Type (Typ)
1395 and then Present (Non_Limited_View (Typ))
1396 and then Is_Legal_Shadow_Entity_In_Body (Typ)
1398 Typ := Non_Limited_View (Typ);
1401 if Ekind (Typ) = E_Incomplete_Type
1402 and then No (Full_View (Typ))
1405 ("prefix of % attribute cannot be an incomplete type");
1410 if not Is_Entity_Name (P)
1411 or else not Is_Type (Entity (P))
1412 or else In_Spec_Expression
1416 Check_Fully_Declared (P_Type, P);
1418 end Check_Not_Incomplete_Type;
1420 ----------------------------
1421 -- Check_Object_Reference --
1422 ----------------------------
1424 procedure Check_Object_Reference (P : Node_Id) is
1428 -- If we need an object, and we have a prefix that is the name of
1429 -- a function entity, convert it into a function call.
1431 if Is_Entity_Name (P)
1432 and then Ekind (Entity (P)) = E_Function
1434 Rtyp := Etype (Entity (P));
1437 Make_Function_Call (Sloc (P),
1438 Name => Relocate_Node (P)));
1440 Analyze_And_Resolve (P, Rtyp);
1442 -- Otherwise we must have an object reference
1444 elsif not Is_Object_Reference (P) then
1445 Error_Attr_P ("prefix of % attribute must be object");
1447 end Check_Object_Reference;
1449 ----------------------------
1450 -- Check_PolyORB_Attribute --
1451 ----------------------------
1453 procedure Check_PolyORB_Attribute is
1455 Validate_Non_Static_Attribute_Function_Call;
1460 if Get_PCS_Name /= Name_PolyORB_DSA then
1462 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
1464 end Check_PolyORB_Attribute;
1466 ------------------------
1467 -- Check_Program_Unit --
1468 ------------------------
1470 procedure Check_Program_Unit is
1472 if Is_Entity_Name (P) then
1474 K : constant Entity_Kind := Ekind (Entity (P));
1475 T : constant Entity_Id := Etype (Entity (P));
1478 if K in Subprogram_Kind
1479 or else K in Task_Kind
1480 or else K in Protected_Kind
1481 or else K = E_Package
1482 or else K in Generic_Unit_Kind
1483 or else (K = E_Variable
1487 Is_Protected_Type (T)))
1494 Error_Attr_P ("prefix of % attribute must be program unit");
1495 end Check_Program_Unit;
1497 ---------------------
1498 -- Check_Real_Type --
1499 ---------------------
1501 procedure Check_Real_Type is
1505 if not Is_Real_Type (P_Type) then
1506 Error_Attr_P ("prefix of % attribute must be real type");
1508 end Check_Real_Type;
1510 -----------------------
1511 -- Check_Scalar_Type --
1512 -----------------------
1514 procedure Check_Scalar_Type is
1518 if not Is_Scalar_Type (P_Type) then
1519 Error_Attr_P ("prefix of % attribute must be scalar type");
1521 end Check_Scalar_Type;
1523 ------------------------------------------
1524 -- Check_SPARK_Restriction_On_Attribute --
1525 ------------------------------------------
1527 procedure Check_SPARK_Restriction_On_Attribute is
1529 Error_Msg_Name_1 := Aname;
1530 Check_SPARK_Restriction ("attribute % is not allowed", P);
1531 end Check_SPARK_Restriction_On_Attribute;
1533 ---------------------------
1534 -- Check_Standard_Prefix --
1535 ---------------------------
1537 procedure Check_Standard_Prefix is
1541 if Nkind (P) /= N_Identifier
1542 or else Chars (P) /= Name_Standard
1544 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1546 end Check_Standard_Prefix;
1548 ----------------------------
1549 -- Check_Stream_Attribute --
1550 ----------------------------
1552 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1556 In_Shared_Var_Procs : Boolean;
1557 -- True when compiling the body of System.Shared_Storage.
1558 -- Shared_Var_Procs. For this runtime package (always compiled in
1559 -- GNAT mode), we allow stream attributes references for limited
1560 -- types for the case where shared passive objects are implemented
1561 -- using stream attributes, which is the default in GNAT's persistent
1562 -- storage implementation.
1565 Validate_Non_Static_Attribute_Function_Call;
1567 -- With the exception of 'Input, Stream attributes are procedures,
1568 -- and can only appear at the position of procedure calls. We check
1569 -- for this here, before they are rewritten, to give a more precise
1572 if Nam = TSS_Stream_Input then
1575 elsif Is_List_Member (N)
1576 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
1583 ("invalid context for attribute%, which is a procedure", N);
1587 Btyp := Implementation_Base_Type (P_Type);
1589 -- Stream attributes not allowed on limited types unless the
1590 -- attribute reference was generated by the expander (in which
1591 -- case the underlying type will be used, as described in Sinfo),
1592 -- or the attribute was specified explicitly for the type itself
1593 -- or one of its ancestors (taking visibility rules into account if
1594 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
1595 -- (with no visibility restriction).
1598 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
1600 if Present (Gen_Body) then
1601 In_Shared_Var_Procs :=
1602 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
1604 In_Shared_Var_Procs := False;
1608 if (Comes_From_Source (N)
1609 and then not (In_Shared_Var_Procs or In_Instance))
1610 and then not Stream_Attribute_Available (P_Type, Nam)
1611 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
1613 Error_Msg_Name_1 := Aname;
1615 if Is_Limited_Type (P_Type) then
1617 ("limited type& has no% attribute", P, P_Type);
1618 Explain_Limited_Type (P_Type, P);
1621 ("attribute% for type& is not available", P, P_Type);
1625 -- Check restriction violations
1627 -- First check the No_Streams restriction, which prohibits the use
1628 -- of explicit stream attributes in the source program. We do not
1629 -- prevent the occurrence of stream attributes in generated code,
1630 -- for instance those generated implicitly for dispatching purposes.
1632 if Comes_From_Source (N) then
1633 Check_Restriction (No_Streams, P);
1636 -- AI05-0057: if restriction No_Default_Stream_Attributes is active,
1637 -- it is illegal to use a predefined elementary type stream attribute
1638 -- either by itself, or more importantly as part of the attribute
1639 -- subprogram for a composite type.
1641 if Restriction_Active (No_Default_Stream_Attributes) then
1646 if Nam = TSS_Stream_Input
1648 Nam = TSS_Stream_Read
1651 Type_Without_Stream_Operation (P_Type, TSS_Stream_Read);
1654 Type_Without_Stream_Operation (P_Type, TSS_Stream_Write);
1658 Check_Restriction (No_Default_Stream_Attributes, N);
1661 ("missing user-defined Stream Read or Write for type&",
1663 if not Is_Elementary_Type (P_Type) then
1665 ("\which is a component of type&", N, P_Type);
1671 -- Check special case of Exception_Id and Exception_Occurrence which
1672 -- are not allowed for restriction No_Exception_Registration.
1674 if Restriction_Check_Required (No_Exception_Registration)
1675 and then (Is_RTE (P_Type, RE_Exception_Id)
1677 Is_RTE (P_Type, RE_Exception_Occurrence))
1679 Check_Restriction (No_Exception_Registration, P);
1682 -- Here we must check that the first argument is an access type
1683 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1685 Analyze_And_Resolve (E1);
1688 -- Note: the double call to Root_Type here is needed because the
1689 -- root type of a class-wide type is the corresponding type (e.g.
1690 -- X for X'Class, and we really want to go to the root.)
1692 if not Is_Access_Type (Etyp)
1693 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1694 RTE (RE_Root_Stream_Type)
1697 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1700 -- Check that the second argument is of the right type if there is
1701 -- one (the Input attribute has only one argument so this is skipped)
1703 if Present (E2) then
1706 if Nam = TSS_Stream_Read
1707 and then not Is_OK_Variable_For_Out_Formal (E2)
1710 ("second argument of % attribute must be a variable", E2);
1713 Resolve (E2, P_Type);
1717 end Check_Stream_Attribute;
1719 -----------------------
1720 -- Check_Task_Prefix --
1721 -----------------------
1723 procedure Check_Task_Prefix is
1727 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1728 -- task interface class-wide types.
1730 if Is_Task_Type (Etype (P))
1731 or else (Is_Access_Type (Etype (P))
1732 and then Is_Task_Type (Designated_Type (Etype (P))))
1733 or else (Ada_Version >= Ada_2005
1734 and then Ekind (Etype (P)) = E_Class_Wide_Type
1735 and then Is_Interface (Etype (P))
1736 and then Is_Task_Interface (Etype (P)))
1741 if Ada_Version >= Ada_2005 then
1743 ("prefix of % attribute must be a task or a task " &
1744 "interface class-wide object");
1747 Error_Attr_P ("prefix of % attribute must be a task");
1750 end Check_Task_Prefix;
1756 -- The possibilities are an entity name denoting a type, or an
1757 -- attribute reference that denotes a type (Base or Class). If
1758 -- the type is incomplete, replace it with its full view.
1760 procedure Check_Type is
1762 if not Is_Entity_Name (P)
1763 or else not Is_Type (Entity (P))
1765 Error_Attr_P ("prefix of % attribute must be a type");
1767 elsif Is_Protected_Self_Reference (P) then
1769 ("prefix of % attribute denotes current instance "
1770 & "(RM 9.4(21/2))");
1772 elsif Ekind (Entity (P)) = E_Incomplete_Type
1773 and then Present (Full_View (Entity (P)))
1775 P_Type := Full_View (Entity (P));
1776 Set_Entity (P, P_Type);
1780 ---------------------
1781 -- Check_Unit_Name --
1782 ---------------------
1784 procedure Check_Unit_Name (Nod : Node_Id) is
1786 if Nkind (Nod) = N_Identifier then
1789 elsif Nkind_In (Nod, N_Selected_Component, N_Expanded_Name) then
1790 Check_Unit_Name (Prefix (Nod));
1792 if Nkind (Selector_Name (Nod)) = N_Identifier then
1797 Error_Attr ("argument for % attribute must be unit name", P);
1798 end Check_Unit_Name;
1804 procedure Error_Attr is
1806 Set_Etype (N, Any_Type);
1807 Set_Entity (N, Any_Type);
1808 raise Bad_Attribute;
1811 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1813 Error_Msg_Name_1 := Aname;
1814 Error_Msg_N (Msg, Error_Node);
1822 procedure Error_Attr_P (Msg : String) is
1824 Error_Msg_Name_1 := Aname;
1825 Error_Msg_F (Msg, P);
1829 ----------------------------
1830 -- Legal_Formal_Attribute --
1831 ----------------------------
1833 procedure Legal_Formal_Attribute is
1837 if not Is_Entity_Name (P)
1838 or else not Is_Type (Entity (P))
1840 Error_Attr_P ("prefix of % attribute must be generic type");
1842 elsif Is_Generic_Actual_Type (Entity (P))
1844 or else In_Inlined_Body
1848 elsif Is_Generic_Type (Entity (P)) then
1849 if not Is_Indefinite_Subtype (Entity (P)) then
1851 ("prefix of % attribute must be indefinite generic type");
1856 ("prefix of % attribute must be indefinite generic type");
1859 Set_Etype (N, Standard_Boolean);
1860 end Legal_Formal_Attribute;
1862 ------------------------
1863 -- Standard_Attribute --
1864 ------------------------
1866 procedure Standard_Attribute (Val : Int) is
1868 Check_Standard_Prefix;
1869 Rewrite (N, Make_Integer_Literal (Loc, Val));
1871 end Standard_Attribute;
1873 -------------------------
1874 -- Unexpected Argument --
1875 -------------------------
1877 procedure Unexpected_Argument (En : Node_Id) is
1879 Error_Attr ("unexpected argument for % attribute", En);
1880 end Unexpected_Argument;
1882 -------------------------------------------------
1883 -- Validate_Non_Static_Attribute_Function_Call --
1884 -------------------------------------------------
1886 -- This function should be moved to Sem_Dist ???
1888 procedure Validate_Non_Static_Attribute_Function_Call is
1890 if In_Preelaborated_Unit
1891 and then not In_Subprogram_Or_Concurrent_Unit
1893 Flag_Non_Static_Expr
1894 ("non-static function call in preelaborated unit!", N);
1896 end Validate_Non_Static_Attribute_Function_Call;
1898 -- Start of processing for Analyze_Attribute
1901 -- Immediate return if unrecognized attribute (already diagnosed
1902 -- by parser, so there is nothing more that we need to do)
1904 if not Is_Attribute_Name (Aname) then
1905 raise Bad_Attribute;
1908 -- Deal with Ada 83 issues
1910 if Comes_From_Source (N) then
1911 if not Attribute_83 (Attr_Id) then
1912 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1913 Error_Msg_Name_1 := Aname;
1914 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1917 if Attribute_Impl_Def (Attr_Id) then
1918 Check_Restriction (No_Implementation_Attributes, N);
1923 -- Deal with Ada 2005 attributes that are
1925 if Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005 then
1926 Check_Restriction (No_Implementation_Attributes, N);
1929 -- Remote access to subprogram type access attribute reference needs
1930 -- unanalyzed copy for tree transformation. The analyzed copy is used
1931 -- for its semantic information (whether prefix is a remote subprogram
1932 -- name), the unanalyzed copy is used to construct new subtree rooted
1933 -- with N_Aggregate which represents a fat pointer aggregate.
1935 if Aname = Name_Access then
1936 Discard_Node (Copy_Separate_Tree (N));
1939 -- Analyze prefix and exit if error in analysis. If the prefix is an
1940 -- incomplete type, use full view if available. Note that there are
1941 -- some attributes for which we do not analyze the prefix, since the
1942 -- prefix is not a normal name.
1944 if Aname /= Name_Elab_Body
1946 Aname /= Name_Elab_Spec
1948 Aname /= Name_UET_Address
1950 Aname /= Name_Enabled
1953 P_Type := Etype (P);
1955 if Is_Entity_Name (P)
1956 and then Present (Entity (P))
1957 and then Is_Type (Entity (P))
1959 if Ekind (Entity (P)) = E_Incomplete_Type then
1960 P_Type := Get_Full_View (P_Type);
1961 Set_Entity (P, P_Type);
1962 Set_Etype (P, P_Type);
1964 elsif Entity (P) = Current_Scope
1965 and then Is_Record_Type (Entity (P))
1967 -- Use of current instance within the type. Verify that if the
1968 -- attribute appears within a constraint, it yields an access
1969 -- type, other uses are illegal.
1977 and then Nkind (Parent (Par)) /= N_Component_Definition
1979 Par := Parent (Par);
1983 and then Nkind (Par) = N_Subtype_Indication
1985 if Attr_Id /= Attribute_Access
1986 and then Attr_Id /= Attribute_Unchecked_Access
1987 and then Attr_Id /= Attribute_Unrestricted_Access
1990 ("in a constraint the current instance can only"
1991 & " be used with an access attribute", N);
1998 if P_Type = Any_Type then
1999 raise Bad_Attribute;
2002 P_Base_Type := Base_Type (P_Type);
2005 -- Analyze expressions that may be present, exiting if an error occurs
2012 E1 := First (Exprs);
2015 -- Check for missing/bad expression (result of previous error)
2017 if No (E1) or else Etype (E1) = Any_Type then
2018 raise Bad_Attribute;
2023 if Present (E2) then
2026 if Etype (E2) = Any_Type then
2027 raise Bad_Attribute;
2030 if Present (Next (E2)) then
2031 Unexpected_Argument (Next (E2));
2036 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
2037 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
2039 if Ada_Version < Ada_2005
2040 and then Is_Overloaded (P)
2041 and then Aname /= Name_Access
2042 and then Aname /= Name_Address
2043 and then Aname /= Name_Code_Address
2044 and then Aname /= Name_Count
2045 and then Aname /= Name_Result
2046 and then Aname /= Name_Unchecked_Access
2048 Error_Attr ("ambiguous prefix for % attribute", P);
2050 elsif Ada_Version >= Ada_2005
2051 and then Is_Overloaded (P)
2052 and then Aname /= Name_Access
2053 and then Aname /= Name_Address
2054 and then Aname /= Name_Code_Address
2055 and then Aname /= Name_Result
2056 and then Aname /= Name_Unchecked_Access
2058 -- Ada 2005 (AI-345): Since protected and task types have primitive
2059 -- entry wrappers, the attributes Count, Caller and AST_Entry require
2062 if Ada_Version >= Ada_2005
2063 and then (Aname = Name_Count
2064 or else Aname = Name_Caller
2065 or else Aname = Name_AST_Entry)
2068 Count : Natural := 0;
2073 Get_First_Interp (P, I, It);
2074 while Present (It.Nam) loop
2075 if Comes_From_Source (It.Nam) then
2081 Get_Next_Interp (I, It);
2085 Error_Attr ("ambiguous prefix for % attribute", P);
2087 Set_Is_Overloaded (P, False);
2092 Error_Attr ("ambiguous prefix for % attribute", P);
2096 -- In SPARK, attributes of private types are only allowed if the full
2097 -- type declaration is visible.
2099 if Is_Entity_Name (P)
2100 and then Present (Entity (P)) -- needed in some cases
2101 and then Is_Type (Entity (P))
2102 and then Is_Private_Type (P_Type)
2103 and then not In_Open_Scopes (Scope (P_Type))
2104 and then not In_Spec_Expression
2106 Check_SPARK_Restriction ("invisible attribute of type", N);
2109 -- Remaining processing depends on attribute
2117 when Attribute_Abort_Signal =>
2118 Check_Standard_Prefix;
2119 Rewrite (N, New_Reference_To (Stand.Abort_Signal, Loc));
2126 when Attribute_Access =>
2127 Analyze_Access_Attribute;
2133 when Attribute_Address =>
2136 -- Check for some junk cases, where we have to allow the address
2137 -- attribute but it does not make much sense, so at least for now
2138 -- just replace with Null_Address.
2140 -- We also do this if the prefix is a reference to the AST_Entry
2141 -- attribute. If expansion is active, the attribute will be
2142 -- replaced by a function call, and address will work fine and
2143 -- get the proper value, but if expansion is not active, then
2144 -- the check here allows proper semantic analysis of the reference.
2146 -- An Address attribute created by expansion is legal even when it
2147 -- applies to other entity-denoting expressions.
2149 if Is_Protected_Self_Reference (P) then
2151 -- Address attribute on a protected object self reference is legal
2155 elsif Is_Entity_Name (P) then
2157 Ent : constant Entity_Id := Entity (P);
2160 if Is_Subprogram (Ent) then
2161 Set_Address_Taken (Ent);
2162 Kill_Current_Values (Ent);
2164 -- An Address attribute is accepted when generated by the
2165 -- compiler for dispatching operation, and an error is
2166 -- issued once the subprogram is frozen (to avoid confusing
2167 -- errors about implicit uses of Address in the dispatch
2168 -- table initialization).
2170 if Has_Pragma_Inline_Always (Entity (P))
2171 and then Comes_From_Source (P)
2174 ("prefix of % attribute cannot be Inline_Always" &
2177 -- It is illegal to apply 'Address to an intrinsic
2178 -- subprogram. This is now formalized in AI05-0095.
2179 -- In an instance, an attempt to obtain 'Address of an
2180 -- intrinsic subprogram (e.g the renaming of a predefined
2181 -- operator that is an actual) raises Program_Error.
2183 elsif Convention (Ent) = Convention_Intrinsic then
2186 Make_Raise_Program_Error (Loc,
2187 Reason => PE_Address_Of_Intrinsic));
2191 ("cannot take Address of intrinsic subprogram", N);
2194 -- Issue an error if prefix denotes an eliminated subprogram
2197 Check_For_Eliminated_Subprogram (P, Ent);
2200 elsif Is_Object (Ent)
2201 or else Ekind (Ent) = E_Label
2203 Set_Address_Taken (Ent);
2205 -- If we have an address of an object, and the attribute
2206 -- comes from source, then set the object as potentially
2207 -- source modified. We do this because the resulting address
2208 -- can potentially be used to modify the variable and we
2209 -- might not detect this, leading to some junk warnings.
2211 Set_Never_Set_In_Source (Ent, False);
2213 elsif (Is_Concurrent_Type (Etype (Ent))
2214 and then Etype (Ent) = Base_Type (Ent))
2215 or else Ekind (Ent) = E_Package
2216 or else Is_Generic_Unit (Ent)
2219 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2222 Error_Attr ("invalid prefix for % attribute", P);
2226 elsif Nkind (P) = N_Attribute_Reference
2227 and then Attribute_Name (P) = Name_AST_Entry
2230 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2232 elsif Is_Object_Reference (P) then
2235 elsif Nkind (P) = N_Selected_Component
2236 and then Is_Subprogram (Entity (Selector_Name (P)))
2240 -- What exactly are we allowing here ??? and is this properly
2241 -- documented in the sinfo documentation for this node ???
2243 elsif not Comes_From_Source (N) then
2247 Error_Attr ("invalid prefix for % attribute", P);
2250 Set_Etype (N, RTE (RE_Address));
2256 when Attribute_Address_Size =>
2257 Standard_Attribute (System_Address_Size);
2263 when Attribute_Adjacent =>
2264 Check_Floating_Point_Type_2;
2265 Set_Etype (N, P_Base_Type);
2266 Resolve (E1, P_Base_Type);
2267 Resolve (E2, P_Base_Type);
2273 when Attribute_Aft =>
2274 Check_Fixed_Point_Type_0;
2275 Set_Etype (N, Universal_Integer);
2281 when Attribute_Alignment =>
2283 -- Don't we need more checking here, cf Size ???
2286 Check_Not_Incomplete_Type;
2288 Set_Etype (N, Universal_Integer);
2294 when Attribute_Asm_Input =>
2295 Check_Asm_Attribute;
2297 -- The back-end may need to take the address of E2
2299 if Is_Entity_Name (E2) then
2300 Set_Address_Taken (Entity (E2));
2303 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2309 when Attribute_Asm_Output =>
2310 Check_Asm_Attribute;
2312 if Etype (E2) = Any_Type then
2315 elsif Aname = Name_Asm_Output then
2316 if not Is_Variable (E2) then
2318 ("second argument for Asm_Output is not variable", E2);
2322 Note_Possible_Modification (E2, Sure => True);
2324 -- The back-end may need to take the address of E2
2326 if Is_Entity_Name (E2) then
2327 Set_Address_Taken (Entity (E2));
2330 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2336 when Attribute_AST_Entry => AST_Entry : declare
2342 -- Indicates if entry family index is present. Note the coding
2343 -- here handles the entry family case, but in fact it cannot be
2344 -- executed currently, because pragma AST_Entry does not permit
2345 -- the specification of an entry family.
2347 procedure Bad_AST_Entry;
2348 -- Signal a bad AST_Entry pragma
2350 function OK_Entry (E : Entity_Id) return Boolean;
2351 -- Checks that E is of an appropriate entity kind for an entry
2352 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2353 -- is set True for the entry family case). In the True case,
2354 -- makes sure that Is_AST_Entry is set on the entry.
2360 procedure Bad_AST_Entry is
2362 Error_Attr_P ("prefix for % attribute must be task entry");
2369 function OK_Entry (E : Entity_Id) return Boolean is
2374 Result := (Ekind (E) = E_Entry_Family);
2376 Result := (Ekind (E) = E_Entry);
2380 if not Is_AST_Entry (E) then
2381 Error_Msg_Name_2 := Aname;
2382 Error_Attr ("% attribute requires previous % pragma", P);
2389 -- Start of processing for AST_Entry
2395 -- Deal with entry family case
2397 if Nkind (P) = N_Indexed_Component then
2405 Ptyp := Etype (Pref);
2407 if Ptyp = Any_Type or else Error_Posted (Pref) then
2411 -- If the prefix is a selected component whose prefix is of an
2412 -- access type, then introduce an explicit dereference.
2413 -- ??? Could we reuse Check_Dereference here?
2415 if Nkind (Pref) = N_Selected_Component
2416 and then Is_Access_Type (Ptyp)
2419 Make_Explicit_Dereference (Sloc (Pref),
2420 Relocate_Node (Pref)));
2421 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2424 -- Prefix can be of the form a.b, where a is a task object
2425 -- and b is one of the entries of the corresponding task type.
2427 if Nkind (Pref) = N_Selected_Component
2428 and then OK_Entry (Entity (Selector_Name (Pref)))
2429 and then Is_Object_Reference (Prefix (Pref))
2430 and then Is_Task_Type (Etype (Prefix (Pref)))
2434 -- Otherwise the prefix must be an entry of a containing task,
2435 -- or of a variable of the enclosing task type.
2438 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2439 Ent := Entity (Pref);
2441 if not OK_Entry (Ent)
2442 or else not In_Open_Scopes (Scope (Ent))
2452 Set_Etype (N, RTE (RE_AST_Handler));
2459 -- Note: when the base attribute appears in the context of a subtype
2460 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2461 -- the following circuit.
2463 when Attribute_Base => Base : declare
2471 if Ada_Version >= Ada_95
2472 and then not Is_Scalar_Type (Typ)
2473 and then not Is_Generic_Type (Typ)
2475 Error_Attr_P ("prefix of Base attribute must be scalar type");
2477 elsif Sloc (Typ) = Standard_Location
2478 and then Base_Type (Typ) = Typ
2479 and then Warn_On_Redundant_Constructs
2481 Error_Msg_NE -- CODEFIX
2482 ("?redundant attribute, & is its own base type", N, Typ);
2485 if Nkind (Parent (N)) /= N_Attribute_Reference then
2486 Error_Msg_Name_1 := Aname;
2487 Check_SPARK_Restriction
2488 ("attribute% is only allowed as prefix of another attribute", P);
2491 Set_Etype (N, Base_Type (Entity (P)));
2492 Set_Entity (N, Base_Type (Entity (P)));
2493 Rewrite (N, New_Reference_To (Entity (N), Loc));
2501 when Attribute_Bit => Bit :
2505 if not Is_Object_Reference (P) then
2506 Error_Attr_P ("prefix for % attribute must be object");
2508 -- What about the access object cases ???
2514 Set_Etype (N, Universal_Integer);
2521 when Attribute_Bit_Order => Bit_Order :
2526 if not Is_Record_Type (P_Type) then
2527 Error_Attr_P ("prefix of % attribute must be record type");
2530 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2532 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2535 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2538 Set_Etype (N, RTE (RE_Bit_Order));
2541 -- Reset incorrect indication of staticness
2543 Set_Is_Static_Expression (N, False);
2550 -- Note: in generated code, we can have a Bit_Position attribute
2551 -- applied to a (naked) record component (i.e. the prefix is an
2552 -- identifier that references an E_Component or E_Discriminant
2553 -- entity directly, and this is interpreted as expected by Gigi.
2554 -- The following code will not tolerate such usage, but when the
2555 -- expander creates this special case, it marks it as analyzed
2556 -- immediately and sets an appropriate type.
2558 when Attribute_Bit_Position =>
2559 if Comes_From_Source (N) then
2563 Set_Etype (N, Universal_Integer);
2569 when Attribute_Body_Version =>
2572 Set_Etype (N, RTE (RE_Version_String));
2578 when Attribute_Callable =>
2580 Set_Etype (N, Standard_Boolean);
2587 when Attribute_Caller => Caller : declare
2594 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2597 if not Is_Entry (Ent) then
2598 Error_Attr ("invalid entry name", N);
2602 Error_Attr ("invalid entry name", N);
2606 for J in reverse 0 .. Scope_Stack.Last loop
2607 S := Scope_Stack.Table (J).Entity;
2609 if S = Scope (Ent) then
2610 Error_Attr ("Caller must appear in matching accept or body", N);
2616 Set_Etype (N, RTE (RO_AT_Task_Id));
2623 when Attribute_Ceiling =>
2624 Check_Floating_Point_Type_1;
2625 Set_Etype (N, P_Base_Type);
2626 Resolve (E1, P_Base_Type);
2632 when Attribute_Class =>
2633 Check_Restriction (No_Dispatch, N);
2637 -- Applying Class to untagged incomplete type is obsolescent in Ada
2638 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
2639 -- this flag gets set by Find_Type in this situation.
2641 if Restriction_Check_Required (No_Obsolescent_Features)
2642 and then Ada_Version >= Ada_2005
2643 and then Ekind (P_Type) = E_Incomplete_Type
2646 DN : constant Node_Id := Declaration_Node (P_Type);
2648 if Nkind (DN) = N_Incomplete_Type_Declaration
2649 and then not Tagged_Present (DN)
2651 Check_Restriction (No_Obsolescent_Features, P);
2660 when Attribute_Code_Address =>
2663 if Nkind (P) = N_Attribute_Reference
2664 and then (Attribute_Name (P) = Name_Elab_Body
2666 Attribute_Name (P) = Name_Elab_Spec)
2670 elsif not Is_Entity_Name (P)
2671 or else (Ekind (Entity (P)) /= E_Function
2673 Ekind (Entity (P)) /= E_Procedure)
2675 Error_Attr ("invalid prefix for % attribute", P);
2676 Set_Address_Taken (Entity (P));
2678 -- Issue an error if the prefix denotes an eliminated subprogram
2681 Check_For_Eliminated_Subprogram (P, Entity (P));
2684 Set_Etype (N, RTE (RE_Address));
2686 ----------------------
2687 -- Compiler_Version --
2688 ----------------------
2690 when Attribute_Compiler_Version =>
2692 Check_Standard_Prefix;
2693 Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
2694 Analyze_And_Resolve (N, Standard_String);
2696 --------------------
2697 -- Component_Size --
2698 --------------------
2700 when Attribute_Component_Size =>
2702 Set_Etype (N, Universal_Integer);
2704 -- Note: unlike other array attributes, unconstrained arrays are OK
2706 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2716 when Attribute_Compose =>
2717 Check_Floating_Point_Type_2;
2718 Set_Etype (N, P_Base_Type);
2719 Resolve (E1, P_Base_Type);
2720 Resolve (E2, Any_Integer);
2726 when Attribute_Constrained =>
2728 Set_Etype (N, Standard_Boolean);
2730 -- Case from RM J.4(2) of constrained applied to private type
2732 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2733 Check_Restriction (No_Obsolescent_Features, P);
2735 if Warn_On_Obsolescent_Feature then
2737 ("constrained for private type is an " &
2738 "obsolescent feature (RM J.4)?", N);
2741 -- If we are within an instance, the attribute must be legal
2742 -- because it was valid in the generic unit. Ditto if this is
2743 -- an inlining of a function declared in an instance.
2746 or else In_Inlined_Body
2750 -- For sure OK if we have a real private type itself, but must
2751 -- be completed, cannot apply Constrained to incomplete type.
2753 elsif Is_Private_Type (Entity (P)) then
2755 -- Note: this is one of the Annex J features that does not
2756 -- generate a warning from -gnatwj, since in fact it seems
2757 -- very useful, and is used in the GNAT runtime.
2759 Check_Not_Incomplete_Type;
2763 -- Normal (non-obsolescent case) of application to object of
2764 -- a discriminated type.
2767 Check_Object_Reference (P);
2769 -- If N does not come from source, then we allow the
2770 -- the attribute prefix to be of a private type whose
2771 -- full type has discriminants. This occurs in cases
2772 -- involving expanded calls to stream attributes.
2774 if not Comes_From_Source (N) then
2775 P_Type := Underlying_Type (P_Type);
2778 -- Must have discriminants or be an access type designating
2779 -- a type with discriminants. If it is a classwide type is ???
2780 -- has unknown discriminants.
2782 if Has_Discriminants (P_Type)
2783 or else Has_Unknown_Discriminants (P_Type)
2785 (Is_Access_Type (P_Type)
2786 and then Has_Discriminants (Designated_Type (P_Type)))
2790 -- Also allow an object of a generic type if extensions allowed
2791 -- and allow this for any type at all.
2793 elsif (Is_Generic_Type (P_Type)
2794 or else Is_Generic_Actual_Type (P_Type))
2795 and then Extensions_Allowed
2801 -- Fall through if bad prefix
2804 ("prefix of % attribute must be object of discriminated type");
2810 when Attribute_Copy_Sign =>
2811 Check_Floating_Point_Type_2;
2812 Set_Etype (N, P_Base_Type);
2813 Resolve (E1, P_Base_Type);
2814 Resolve (E2, P_Base_Type);
2820 when Attribute_Count => Count :
2829 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2832 if Ekind (Ent) /= E_Entry then
2833 Error_Attr ("invalid entry name", N);
2836 elsif Nkind (P) = N_Indexed_Component then
2837 if not Is_Entity_Name (Prefix (P))
2838 or else No (Entity (Prefix (P)))
2839 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2841 if Nkind (Prefix (P)) = N_Selected_Component
2842 and then Present (Entity (Selector_Name (Prefix (P))))
2843 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2847 ("attribute % must apply to entry of current task", P);
2850 Error_Attr ("invalid entry family name", P);
2855 Ent := Entity (Prefix (P));
2858 elsif Nkind (P) = N_Selected_Component
2859 and then Present (Entity (Selector_Name (P)))
2860 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2863 ("attribute % must apply to entry of current task", P);
2866 Error_Attr ("invalid entry name", N);
2870 for J in reverse 0 .. Scope_Stack.Last loop
2871 S := Scope_Stack.Table (J).Entity;
2873 if S = Scope (Ent) then
2874 if Nkind (P) = N_Expanded_Name then
2875 Tsk := Entity (Prefix (P));
2877 -- The prefix denotes either the task type, or else a
2878 -- single task whose task type is being analyzed.
2883 or else (not Is_Type (Tsk)
2884 and then Etype (Tsk) = S
2885 and then not (Comes_From_Source (S)))
2890 ("Attribute % must apply to entry of current task", N);
2896 elsif Ekind (Scope (Ent)) in Task_Kind
2898 not Ekind_In (S, E_Loop, E_Block, E_Entry, E_Entry_Family)
2900 Error_Attr ("Attribute % cannot appear in inner unit", N);
2902 elsif Ekind (Scope (Ent)) = E_Protected_Type
2903 and then not Has_Completion (Scope (Ent))
2905 Error_Attr ("attribute % can only be used inside body", N);
2909 if Is_Overloaded (P) then
2911 Index : Interp_Index;
2915 Get_First_Interp (P, Index, It);
2917 while Present (It.Nam) loop
2918 if It.Nam = Ent then
2921 -- Ada 2005 (AI-345): Do not consider primitive entry
2922 -- wrappers generated for task or protected types.
2924 elsif Ada_Version >= Ada_2005
2925 and then not Comes_From_Source (It.Nam)
2930 Error_Attr ("ambiguous entry name", N);
2933 Get_Next_Interp (Index, It);
2938 Set_Etype (N, Universal_Integer);
2941 -----------------------
2942 -- Default_Bit_Order --
2943 -----------------------
2945 when Attribute_Default_Bit_Order => Default_Bit_Order :
2947 Check_Standard_Prefix;
2949 if Bytes_Big_Endian then
2951 Make_Integer_Literal (Loc, False_Value));
2954 Make_Integer_Literal (Loc, True_Value));
2957 Set_Etype (N, Universal_Integer);
2958 Set_Is_Static_Expression (N);
2959 end Default_Bit_Order;
2965 when Attribute_Definite =>
2966 Legal_Formal_Attribute;
2972 when Attribute_Delta =>
2973 Check_Fixed_Point_Type_0;
2974 Set_Etype (N, Universal_Real);
2980 when Attribute_Denorm =>
2981 Check_Floating_Point_Type_0;
2982 Set_Etype (N, Standard_Boolean);
2988 when Attribute_Digits =>
2992 if not Is_Floating_Point_Type (P_Type)
2993 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2996 ("prefix of % attribute must be float or decimal type");
2999 Set_Etype (N, Universal_Integer);
3005 -- Also handles processing for Elab_Spec
3007 when Attribute_Elab_Body | Attribute_Elab_Spec =>
3009 Check_Unit_Name (P);
3010 Set_Etype (N, Standard_Void_Type);
3012 -- We have to manually call the expander in this case to get
3013 -- the necessary expansion (normally attributes that return
3014 -- entities are not expanded).
3022 -- Shares processing with Elab_Body
3028 when Attribute_Elaborated =>
3030 Check_Unit_Name (P);
3031 Set_Etype (N, Standard_Boolean);
3037 when Attribute_Emax =>
3038 Check_Floating_Point_Type_0;
3039 Set_Etype (N, Universal_Integer);
3045 when Attribute_Enabled =>
3046 Check_Either_E0_Or_E1;
3048 if Present (E1) then
3049 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
3050 Error_Msg_N ("entity name expected for Enabled attribute", E1);
3055 if Nkind (P) /= N_Identifier then
3056 Error_Msg_N ("identifier expected (check name)", P);
3057 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
3058 Error_Msg_N ("& is not a recognized check name", P);
3061 Set_Etype (N, Standard_Boolean);
3067 when Attribute_Enum_Rep => Enum_Rep : declare
3069 if Present (E1) then
3071 Check_Discrete_Type;
3072 Resolve (E1, P_Base_Type);
3075 if not Is_Entity_Name (P)
3076 or else (not Is_Object (Entity (P))
3078 Ekind (Entity (P)) /= E_Enumeration_Literal)
3081 ("prefix of % attribute must be " &
3082 "discrete type/object or enum literal");
3086 Set_Etype (N, Universal_Integer);
3093 when Attribute_Enum_Val => Enum_Val : begin
3097 if not Is_Enumeration_Type (P_Type) then
3098 Error_Attr_P ("prefix of % attribute must be enumeration type");
3101 -- If the enumeration type has a standard representation, the effect
3102 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3104 if not Has_Non_Standard_Rep (P_Base_Type) then
3106 Make_Attribute_Reference (Loc,
3107 Prefix => Relocate_Node (Prefix (N)),
3108 Attribute_Name => Name_Val,
3109 Expressions => New_List (Relocate_Node (E1))));
3110 Analyze_And_Resolve (N, P_Base_Type);
3112 -- Non-standard representation case (enumeration with holes)
3116 Resolve (E1, Any_Integer);
3117 Set_Etype (N, P_Base_Type);
3125 when Attribute_Epsilon =>
3126 Check_Floating_Point_Type_0;
3127 Set_Etype (N, Universal_Real);
3133 when Attribute_Exponent =>
3134 Check_Floating_Point_Type_1;
3135 Set_Etype (N, Universal_Integer);
3136 Resolve (E1, P_Base_Type);
3142 when Attribute_External_Tag =>
3146 Set_Etype (N, Standard_String);
3148 if not Is_Tagged_Type (P_Type) then
3149 Error_Attr_P ("prefix of % attribute must be tagged");
3156 when Attribute_Fast_Math =>
3157 Check_Standard_Prefix;
3159 if Opt.Fast_Math then
3160 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
3162 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
3169 when Attribute_First =>
3170 Check_Array_Or_Scalar_Type;
3171 Bad_Attribute_For_Predicate;
3177 when Attribute_First_Bit =>
3179 Set_Etype (N, Universal_Integer);
3185 when Attribute_Fixed_Value =>
3187 Check_Fixed_Point_Type;
3188 Resolve (E1, Any_Integer);
3189 Set_Etype (N, P_Base_Type);
3195 when Attribute_Floor =>
3196 Check_Floating_Point_Type_1;
3197 Set_Etype (N, P_Base_Type);
3198 Resolve (E1, P_Base_Type);
3204 when Attribute_Fore =>
3205 Check_Fixed_Point_Type_0;
3206 Set_Etype (N, Universal_Integer);
3212 when Attribute_Fraction =>
3213 Check_Floating_Point_Type_1;
3214 Set_Etype (N, P_Base_Type);
3215 Resolve (E1, P_Base_Type);
3221 when Attribute_From_Any =>
3223 Check_PolyORB_Attribute;
3224 Set_Etype (N, P_Base_Type);
3226 -----------------------
3227 -- Has_Access_Values --
3228 -----------------------
3230 when Attribute_Has_Access_Values =>
3233 Set_Etype (N, Standard_Boolean);
3235 -----------------------
3236 -- Has_Tagged_Values --
3237 -----------------------
3239 when Attribute_Has_Tagged_Values =>
3242 Set_Etype (N, Standard_Boolean);
3244 -----------------------
3245 -- Has_Discriminants --
3246 -----------------------
3248 when Attribute_Has_Discriminants =>
3249 Legal_Formal_Attribute;
3255 when Attribute_Identity =>
3259 if Etype (P) = Standard_Exception_Type then
3260 Set_Etype (N, RTE (RE_Exception_Id));
3262 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3263 -- task interface class-wide types.
3265 elsif Is_Task_Type (Etype (P))
3266 or else (Is_Access_Type (Etype (P))
3267 and then Is_Task_Type (Designated_Type (Etype (P))))
3268 or else (Ada_Version >= Ada_2005
3269 and then Ekind (Etype (P)) = E_Class_Wide_Type
3270 and then Is_Interface (Etype (P))
3271 and then Is_Task_Interface (Etype (P)))
3274 Set_Etype (N, RTE (RO_AT_Task_Id));
3277 if Ada_Version >= Ada_2005 then
3279 ("prefix of % attribute must be an exception, a " &
3280 "task or a task interface class-wide object");
3283 ("prefix of % attribute must be a task or an exception");
3291 when Attribute_Image => Image :
3293 Check_SPARK_Restriction_On_Attribute;
3295 Set_Etype (N, Standard_String);
3297 if Is_Real_Type (P_Type) then
3298 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3299 Error_Msg_Name_1 := Aname;
3301 ("(Ada 83) % attribute not allowed for real types", N);
3305 if Is_Enumeration_Type (P_Type) then
3306 Check_Restriction (No_Enumeration_Maps, N);
3310 Resolve (E1, P_Base_Type);
3312 Validate_Non_Static_Attribute_Function_Call;
3319 when Attribute_Img => Img :
3322 Set_Etype (N, Standard_String);
3324 if not Is_Scalar_Type (P_Type)
3325 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3328 ("prefix of % attribute must be scalar object name");
3338 when Attribute_Input =>
3340 Check_Stream_Attribute (TSS_Stream_Input);
3341 Set_Etype (N, P_Base_Type);
3347 when Attribute_Integer_Value =>
3350 Resolve (E1, Any_Fixed);
3352 -- Signal an error if argument type is not a specific fixed-point
3353 -- subtype. An error has been signalled already if the argument
3354 -- was not of a fixed-point type.
3356 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3357 Error_Attr ("argument of % must be of a fixed-point type", E1);
3360 Set_Etype (N, P_Base_Type);
3366 when Attribute_Invalid_Value =>
3369 Set_Etype (N, P_Base_Type);
3370 Invalid_Value_Used := True;
3376 when Attribute_Large =>
3379 Set_Etype (N, Universal_Real);
3385 when Attribute_Last =>
3386 Check_Array_Or_Scalar_Type;
3387 Bad_Attribute_For_Predicate;
3393 when Attribute_Last_Bit =>
3395 Set_Etype (N, Universal_Integer);
3401 when Attribute_Leading_Part =>
3402 Check_Floating_Point_Type_2;
3403 Set_Etype (N, P_Base_Type);
3404 Resolve (E1, P_Base_Type);
3405 Resolve (E2, Any_Integer);
3411 when Attribute_Length =>
3413 Set_Etype (N, Universal_Integer);
3419 when Attribute_Machine =>
3420 Check_Floating_Point_Type_1;
3421 Set_Etype (N, P_Base_Type);
3422 Resolve (E1, P_Base_Type);
3428 when Attribute_Machine_Emax =>
3429 Check_Floating_Point_Type_0;
3430 Set_Etype (N, Universal_Integer);
3436 when Attribute_Machine_Emin =>
3437 Check_Floating_Point_Type_0;
3438 Set_Etype (N, Universal_Integer);
3440 ----------------------
3441 -- Machine_Mantissa --
3442 ----------------------
3444 when Attribute_Machine_Mantissa =>
3445 Check_Floating_Point_Type_0;
3446 Set_Etype (N, Universal_Integer);
3448 -----------------------
3449 -- Machine_Overflows --
3450 -----------------------
3452 when Attribute_Machine_Overflows =>
3455 Set_Etype (N, Standard_Boolean);
3461 when Attribute_Machine_Radix =>
3464 Set_Etype (N, Universal_Integer);
3466 ----------------------
3467 -- Machine_Rounding --
3468 ----------------------
3470 when Attribute_Machine_Rounding =>
3471 Check_Floating_Point_Type_1;
3472 Set_Etype (N, P_Base_Type);
3473 Resolve (E1, P_Base_Type);
3475 --------------------
3476 -- Machine_Rounds --
3477 --------------------
3479 when Attribute_Machine_Rounds =>
3482 Set_Etype (N, Standard_Boolean);
3488 when Attribute_Machine_Size =>
3491 Check_Not_Incomplete_Type;
3492 Set_Etype (N, Universal_Integer);
3498 when Attribute_Mantissa =>
3501 Set_Etype (N, Universal_Integer);
3507 when Attribute_Max =>
3510 Resolve (E1, P_Base_Type);
3511 Resolve (E2, P_Base_Type);
3512 Set_Etype (N, P_Base_Type);
3514 ----------------------------------
3515 -- Max_Alignment_For_Allocation --
3516 -- Max_Size_In_Storage_Elements --
3517 ----------------------------------
3519 when Attribute_Max_Alignment_For_Allocation |
3520 Attribute_Max_Size_In_Storage_Elements =>
3523 Check_Not_Incomplete_Type;
3524 Set_Etype (N, Universal_Integer);
3526 -----------------------
3527 -- Maximum_Alignment --
3528 -----------------------
3530 when Attribute_Maximum_Alignment =>
3531 Standard_Attribute (Ttypes.Maximum_Alignment);
3533 --------------------
3534 -- Mechanism_Code --
3535 --------------------
3537 when Attribute_Mechanism_Code =>
3538 if not Is_Entity_Name (P)
3539 or else not Is_Subprogram (Entity (P))
3541 Error_Attr_P ("prefix of % attribute must be subprogram");
3544 Check_Either_E0_Or_E1;
3546 if Present (E1) then
3547 Resolve (E1, Any_Integer);
3548 Set_Etype (E1, Standard_Integer);
3550 if not Is_Static_Expression (E1) then
3551 Flag_Non_Static_Expr
3552 ("expression for parameter number must be static!", E1);
3555 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3556 or else UI_To_Int (Intval (E1)) < 0
3558 Error_Attr ("invalid parameter number for % attribute", E1);
3562 Set_Etype (N, Universal_Integer);
3568 when Attribute_Min =>
3571 Resolve (E1, P_Base_Type);
3572 Resolve (E2, P_Base_Type);
3573 Set_Etype (N, P_Base_Type);
3579 when Attribute_Mod =>
3581 -- Note: this attribute is only allowed in Ada 2005 mode, but
3582 -- we do not need to test that here, since Mod is only recognized
3583 -- as an attribute name in Ada 2005 mode during the parse.
3586 Check_Modular_Integer_Type;
3587 Resolve (E1, Any_Integer);
3588 Set_Etype (N, P_Base_Type);
3594 when Attribute_Model =>
3595 Check_Floating_Point_Type_1;
3596 Set_Etype (N, P_Base_Type);
3597 Resolve (E1, P_Base_Type);
3603 when Attribute_Model_Emin =>
3604 Check_Floating_Point_Type_0;
3605 Set_Etype (N, Universal_Integer);
3611 when Attribute_Model_Epsilon =>
3612 Check_Floating_Point_Type_0;
3613 Set_Etype (N, Universal_Real);
3615 --------------------
3616 -- Model_Mantissa --
3617 --------------------
3619 when Attribute_Model_Mantissa =>
3620 Check_Floating_Point_Type_0;
3621 Set_Etype (N, Universal_Integer);
3627 when Attribute_Model_Small =>
3628 Check_Floating_Point_Type_0;
3629 Set_Etype (N, Universal_Real);
3635 when Attribute_Modulus =>
3637 Check_Modular_Integer_Type;
3638 Set_Etype (N, Universal_Integer);
3640 --------------------
3641 -- Null_Parameter --
3642 --------------------
3644 when Attribute_Null_Parameter => Null_Parameter : declare
3645 Parnt : constant Node_Id := Parent (N);
3646 GParnt : constant Node_Id := Parent (Parnt);
3648 procedure Bad_Null_Parameter (Msg : String);
3649 -- Used if bad Null parameter attribute node is found. Issues
3650 -- given error message, and also sets the type to Any_Type to
3651 -- avoid blowups later on from dealing with a junk node.
3653 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3654 -- Called to check that Proc_Ent is imported subprogram
3656 ------------------------
3657 -- Bad_Null_Parameter --
3658 ------------------------
3660 procedure Bad_Null_Parameter (Msg : String) is
3662 Error_Msg_N (Msg, N);
3663 Set_Etype (N, Any_Type);
3664 end Bad_Null_Parameter;
3666 ----------------------
3667 -- Must_Be_Imported --
3668 ----------------------
3670 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3671 Pent : constant Entity_Id := Ultimate_Alias (Proc_Ent);
3674 -- Ignore check if procedure not frozen yet (we will get
3675 -- another chance when the default parameter is reanalyzed)
3677 if not Is_Frozen (Pent) then
3680 elsif not Is_Imported (Pent) then
3682 ("Null_Parameter can only be used with imported subprogram");
3687 end Must_Be_Imported;
3689 -- Start of processing for Null_Parameter
3694 Set_Etype (N, P_Type);
3696 -- Case of attribute used as default expression
3698 if Nkind (Parnt) = N_Parameter_Specification then
3699 Must_Be_Imported (Defining_Entity (GParnt));
3701 -- Case of attribute used as actual for subprogram (positional)
3703 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3705 and then Is_Entity_Name (Name (Parnt))
3707 Must_Be_Imported (Entity (Name (Parnt)));
3709 -- Case of attribute used as actual for subprogram (named)
3711 elsif Nkind (Parnt) = N_Parameter_Association
3712 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3714 and then Is_Entity_Name (Name (GParnt))
3716 Must_Be_Imported (Entity (Name (GParnt)));
3718 -- Not an allowed case
3722 ("Null_Parameter must be actual or default parameter");
3730 when Attribute_Object_Size =>
3733 Check_Not_Incomplete_Type;
3734 Set_Etype (N, Universal_Integer);
3740 when Attribute_Old =>
3742 -- The attribute reference is a primary. If expressions follow, the
3743 -- attribute reference is an indexable object, so rewrite the node
3746 if Present (E1) then
3748 Make_Indexed_Component (Loc,
3750 Make_Attribute_Reference (Loc,
3751 Prefix => Relocate_Node (Prefix (N)),
3752 Attribute_Name => Name_Old),
3753 Expressions => Expressions (N)));
3760 Set_Etype (N, P_Type);
3762 if No (Current_Subprogram) then
3763 Error_Attr ("attribute % can only appear within subprogram", N);
3766 if Is_Limited_Type (P_Type) then
3767 Error_Attr ("attribute % cannot apply to limited objects", P);
3770 if Is_Entity_Name (P)
3771 and then Is_Constant_Object (Entity (P))
3774 ("?attribute Old applied to constant has no effect", P);
3777 -- Check that the expression does not refer to local entities
3779 Check_Local : declare
3780 Subp : Entity_Id := Current_Subprogram;
3782 function Process (N : Node_Id) return Traverse_Result;
3783 -- Check that N does not contain references to local variables or
3784 -- other local entities of Subp.
3790 function Process (N : Node_Id) return Traverse_Result is
3792 if Is_Entity_Name (N)
3793 and then Present (Entity (N))
3794 and then not Is_Formal (Entity (N))
3795 and then Enclosing_Subprogram (Entity (N)) = Subp
3797 Error_Msg_Node_1 := Entity (N);
3799 ("attribute % cannot refer to local variable&", N);
3805 procedure Check_No_Local is new Traverse_Proc;
3807 -- Start of processing for Check_Local
3812 if In_Parameter_Specification (P) then
3814 -- We have additional restrictions on using 'Old in parameter
3817 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3819 -- Check that there is no reference to the enclosing
3820 -- subprogram local variables. Otherwise, we might end up
3821 -- being called from the enclosing subprogram and thus using
3822 -- 'Old on a local variable which is not defined at entry
3825 Subp := Enclosing_Subprogram (Current_Subprogram);
3829 -- We must prevent default expression of library-level
3830 -- subprogram from using 'Old, as the subprogram may be
3831 -- used in elaboration code for which there is no enclosing
3835 ("attribute % can only appear within subprogram", N);
3844 when Attribute_Output =>
3846 Check_Stream_Attribute (TSS_Stream_Output);
3847 Set_Etype (N, Standard_Void_Type);
3848 Resolve (N, Standard_Void_Type);
3854 when Attribute_Partition_ID => Partition_Id :
3858 if P_Type /= Any_Type then
3859 if not Is_Library_Level_Entity (Entity (P)) then
3861 ("prefix of % attribute must be library-level entity");
3863 -- The defining entity of prefix should not be declared inside a
3864 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3866 elsif Is_Entity_Name (P)
3867 and then Is_Pure (Entity (P))
3869 Error_Attr_P ("prefix of% attribute must not be declared pure");
3873 Set_Etype (N, Universal_Integer);
3876 -------------------------
3877 -- Passed_By_Reference --
3878 -------------------------
3880 when Attribute_Passed_By_Reference =>
3883 Set_Etype (N, Standard_Boolean);
3889 when Attribute_Pool_Address =>
3891 Set_Etype (N, RTE (RE_Address));
3897 when Attribute_Pos =>
3898 Check_Discrete_Type;
3901 if Is_Boolean_Type (P_Type) then
3902 Error_Msg_Name_1 := Aname;
3903 Error_Msg_Name_2 := Chars (P_Type);
3904 Check_SPARK_Restriction
3905 ("attribute% is not allowed for type%", P);
3908 Resolve (E1, P_Base_Type);
3909 Set_Etype (N, Universal_Integer);
3915 when Attribute_Position =>
3917 Set_Etype (N, Universal_Integer);
3923 when Attribute_Pred =>
3927 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
3928 Error_Msg_Name_1 := Aname;
3929 Error_Msg_Name_2 := Chars (P_Type);
3930 Check_SPARK_Restriction
3931 ("attribute% is not allowed for type%", P);
3934 Resolve (E1, P_Base_Type);
3935 Set_Etype (N, P_Base_Type);
3937 -- Nothing to do for real type case
3939 if Is_Real_Type (P_Type) then
3942 -- If not modular type, test for overflow check required
3945 if not Is_Modular_Integer_Type (P_Type)
3946 and then not Range_Checks_Suppressed (P_Base_Type)
3948 Enable_Range_Check (E1);
3956 -- Ada 2005 (AI-327): Dynamic ceiling priorities
3958 when Attribute_Priority =>
3959 if Ada_Version < Ada_2005 then
3960 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
3965 -- The prefix must be a protected object (AARM D.5.2 (2/2))
3969 if Is_Protected_Type (Etype (P))
3970 or else (Is_Access_Type (Etype (P))
3971 and then Is_Protected_Type (Designated_Type (Etype (P))))
3973 Resolve (P, Etype (P));
3975 Error_Attr_P ("prefix of % attribute must be a protected object");
3978 Set_Etype (N, Standard_Integer);
3980 -- Must be called from within a protected procedure or entry of the
3981 -- protected object.
3988 while S /= Etype (P)
3989 and then S /= Standard_Standard
3994 if S = Standard_Standard then
3995 Error_Attr ("the attribute % is only allowed inside protected "
4000 Validate_Non_Static_Attribute_Function_Call;
4006 when Attribute_Range =>
4007 Check_Array_Or_Scalar_Type;
4008 Bad_Attribute_For_Predicate;
4010 if Ada_Version = Ada_83
4011 and then Is_Scalar_Type (P_Type)
4012 and then Comes_From_Source (N)
4015 ("(Ada 83) % attribute not allowed for scalar type", P);
4022 when Attribute_Result => Result : declare
4024 -- The enclosing scope, excluding loops for quantified expressions
4027 -- During analysis, CS is the postcondition subprogram and PS the
4028 -- source subprogram to which the postcondition applies. During
4029 -- pre-analysis, CS is the scope of the subprogram declaration.
4032 -- During pre-analysis, Prag is the enclosing pragma node if any
4035 -- Find enclosing scopes, excluding loops
4037 CS := Current_Scope;
4038 while Ekind (CS) = E_Loop loop
4044 -- If the enclosing subprogram is always inlined, the enclosing
4045 -- postcondition will not be propagated to the expanded call.
4047 if not In_Spec_Expression
4048 and then Has_Pragma_Inline_Always (PS)
4049 and then Warn_On_Redundant_Constructs
4052 ("postconditions on inlined functions not enforced?", N);
4055 -- If we are in the scope of a function and in Spec_Expression mode,
4056 -- this is likely the prescan of the postcondition pragma, and we
4057 -- just set the proper type. If there is an error it will be caught
4058 -- when the real Analyze call is done.
4060 if Ekind (CS) = E_Function
4061 and then In_Spec_Expression
4065 if Chars (CS) /= Chars (P) then
4066 Error_Msg_Name_1 := Name_Result;
4069 ("incorrect prefix for % attribute, expected &", P, CS);
4073 -- Check in postcondition of function
4076 while not Nkind_In (Prag, N_Pragma,
4077 N_Function_Specification,
4080 Prag := Parent (Prag);
4083 if Nkind (Prag) /= N_Pragma then
4085 ("% attribute can only appear in postcondition of function",
4088 elsif Get_Pragma_Id (Prag) = Pragma_Test_Case then
4090 Arg_Ens : constant Node_Id :=
4091 Get_Ensures_From_Test_Case_Pragma (Prag);
4096 while Arg /= Prag and Arg /= Arg_Ens loop
4097 Arg := Parent (Arg);
4100 if Arg /= Arg_Ens then
4101 Error_Attr ("% attribute misplaced inside Test_Case", P);
4105 elsif Get_Pragma_Id (Prag) /= Pragma_Postcondition then
4107 ("% attribute can only appear in postcondition of function",
4111 -- The attribute reference is a primary. If expressions follow,
4112 -- the attribute reference is really an indexable object, so
4113 -- rewrite and analyze as an indexed component.
4115 if Present (E1) then
4117 Make_Indexed_Component (Loc,
4119 Make_Attribute_Reference (Loc,
4120 Prefix => Relocate_Node (Prefix (N)),
4121 Attribute_Name => Name_Result),
4122 Expressions => Expressions (N)));
4127 Set_Etype (N, Etype (CS));
4129 -- If several functions with that name are visible,
4130 -- the intended one is the current scope.
4132 if Is_Overloaded (P) then
4134 Set_Is_Overloaded (P, False);
4137 -- Body case, where we must be inside a generated _Postcondition
4138 -- procedure, and the prefix must be on the scope stack, or else
4139 -- the attribute use is definitely misplaced. The condition itself
4140 -- may have generated transient scopes, and is not necessarily the
4144 while Present (CS) and then CS /= Standard_Standard loop
4145 if Chars (CS) = Name_uPostconditions then
4154 if Chars (CS) = Name_uPostconditions
4155 and then Ekind (PS) = E_Function
4159 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
4160 and then Chars (P) = Chars (PS)
4164 -- Within an instance, the prefix designates the local renaming
4165 -- of the original generic.
4167 elsif Is_Entity_Name (P)
4168 and then Ekind (Entity (P)) = E_Function
4169 and then Present (Alias (Entity (P)))
4170 and then Chars (Alias (Entity (P))) = Chars (PS)
4176 ("incorrect prefix for % attribute, expected &", P, PS);
4180 Rewrite (N, Make_Identifier (Sloc (N), Name_uResult));
4181 Analyze_And_Resolve (N, Etype (PS));
4185 ("% attribute can only appear in postcondition of function",
4195 when Attribute_Range_Length =>
4197 Check_Discrete_Type;
4198 Set_Etype (N, Universal_Integer);
4204 when Attribute_Read =>
4206 Check_Stream_Attribute (TSS_Stream_Read);
4207 Set_Etype (N, Standard_Void_Type);
4208 Resolve (N, Standard_Void_Type);
4209 Note_Possible_Modification (E2, Sure => True);
4215 when Attribute_Ref =>
4219 if Nkind (P) /= N_Expanded_Name
4220 or else not Is_RTE (P_Type, RE_Address)
4222 Error_Attr_P ("prefix of % attribute must be System.Address");
4225 Analyze_And_Resolve (E1, Any_Integer);
4226 Set_Etype (N, RTE (RE_Address));
4232 when Attribute_Remainder =>
4233 Check_Floating_Point_Type_2;
4234 Set_Etype (N, P_Base_Type);
4235 Resolve (E1, P_Base_Type);
4236 Resolve (E2, P_Base_Type);
4242 when Attribute_Round =>
4244 Check_Decimal_Fixed_Point_Type;
4245 Set_Etype (N, P_Base_Type);
4247 -- Because the context is universal_real (3.5.10(12)) it is a legal
4248 -- context for a universal fixed expression. This is the only
4249 -- attribute whose functional description involves U_R.
4251 if Etype (E1) = Universal_Fixed then
4253 Conv : constant Node_Id := Make_Type_Conversion (Loc,
4254 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
4255 Expression => Relocate_Node (E1));
4263 Resolve (E1, Any_Real);
4269 when Attribute_Rounding =>
4270 Check_Floating_Point_Type_1;
4271 Set_Etype (N, P_Base_Type);
4272 Resolve (E1, P_Base_Type);
4278 when Attribute_Safe_Emax =>
4279 Check_Floating_Point_Type_0;
4280 Set_Etype (N, Universal_Integer);
4286 when Attribute_Safe_First =>
4287 Check_Floating_Point_Type_0;
4288 Set_Etype (N, Universal_Real);
4294 when Attribute_Safe_Large =>
4297 Set_Etype (N, Universal_Real);
4303 when Attribute_Safe_Last =>
4304 Check_Floating_Point_Type_0;
4305 Set_Etype (N, Universal_Real);
4311 when Attribute_Safe_Small =>
4314 Set_Etype (N, Universal_Real);
4320 when Attribute_Scale =>
4322 Check_Decimal_Fixed_Point_Type;
4323 Set_Etype (N, Universal_Integer);
4329 when Attribute_Scaling =>
4330 Check_Floating_Point_Type_2;
4331 Set_Etype (N, P_Base_Type);
4332 Resolve (E1, P_Base_Type);
4338 when Attribute_Signed_Zeros =>
4339 Check_Floating_Point_Type_0;
4340 Set_Etype (N, Standard_Boolean);
4346 when Attribute_Size | Attribute_VADS_Size => Size :
4350 -- If prefix is parameterless function call, rewrite and resolve
4353 if Is_Entity_Name (P)
4354 and then Ekind (Entity (P)) = E_Function
4358 -- Similar processing for a protected function call
4360 elsif Nkind (P) = N_Selected_Component
4361 and then Ekind (Entity (Selector_Name (P))) = E_Function
4366 if Is_Object_Reference (P) then
4367 Check_Object_Reference (P);
4369 elsif Is_Entity_Name (P)
4370 and then (Is_Type (Entity (P))
4371 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4375 elsif Nkind (P) = N_Type_Conversion
4376 and then not Comes_From_Source (P)
4381 Error_Attr_P ("invalid prefix for % attribute");
4384 Check_Not_Incomplete_Type;
4386 Set_Etype (N, Universal_Integer);
4393 when Attribute_Small =>
4396 Set_Etype (N, Universal_Real);
4402 when Attribute_Storage_Pool => Storage_Pool :
4406 if Is_Access_Type (P_Type) then
4407 if Ekind (P_Type) = E_Access_Subprogram_Type then
4409 ("cannot use % attribute for access-to-subprogram type");
4412 -- Set appropriate entity
4414 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4415 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4417 Set_Entity (N, RTE (RE_Global_Pool_Object));
4420 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4422 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4423 -- Storage_Pool since this attribute is not defined for such
4424 -- types (RM E.2.3(22)).
4426 Validate_Remote_Access_To_Class_Wide_Type (N);
4429 Error_Attr_P ("prefix of % attribute must be access type");
4437 when Attribute_Storage_Size => Storage_Size :
4441 if Is_Task_Type (P_Type) then
4442 Set_Etype (N, Universal_Integer);
4444 -- Use with tasks is an obsolescent feature
4446 Check_Restriction (No_Obsolescent_Features, P);
4448 elsif Is_Access_Type (P_Type) then
4449 if Ekind (P_Type) = E_Access_Subprogram_Type then
4451 ("cannot use % attribute for access-to-subprogram type");
4454 if Is_Entity_Name (P)
4455 and then Is_Type (Entity (P))
4458 Set_Etype (N, Universal_Integer);
4460 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4461 -- Storage_Size since this attribute is not defined for
4462 -- such types (RM E.2.3(22)).
4464 Validate_Remote_Access_To_Class_Wide_Type (N);
4466 -- The prefix is allowed to be an implicit dereference
4467 -- of an access value designating a task.
4471 Set_Etype (N, Universal_Integer);
4475 Error_Attr_P ("prefix of % attribute must be access or task type");
4483 when Attribute_Storage_Unit =>
4484 Standard_Attribute (Ttypes.System_Storage_Unit);
4490 when Attribute_Stream_Size =>
4494 if Is_Entity_Name (P)
4495 and then Is_Elementary_Type (Entity (P))
4497 Set_Etype (N, Universal_Integer);
4499 Error_Attr_P ("invalid prefix for % attribute");
4506 when Attribute_Stub_Type =>
4510 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4512 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4515 ("prefix of% attribute must be remote access to classwide");
4522 when Attribute_Succ =>
4526 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
4527 Error_Msg_Name_1 := Aname;
4528 Error_Msg_Name_2 := Chars (P_Type);
4529 Check_SPARK_Restriction
4530 ("attribute% is not allowed for type%", P);
4533 Resolve (E1, P_Base_Type);
4534 Set_Etype (N, P_Base_Type);
4536 -- Nothing to do for real type case
4538 if Is_Real_Type (P_Type) then
4541 -- If not modular type, test for overflow check required
4544 if not Is_Modular_Integer_Type (P_Type)
4545 and then not Range_Checks_Suppressed (P_Base_Type)
4547 Enable_Range_Check (E1);
4555 when Attribute_Tag => Tag :
4560 if not Is_Tagged_Type (P_Type) then
4561 Error_Attr_P ("prefix of % attribute must be tagged");
4563 -- Next test does not apply to generated code
4564 -- why not, and what does the illegal reference mean???
4566 elsif Is_Object_Reference (P)
4567 and then not Is_Class_Wide_Type (P_Type)
4568 and then Comes_From_Source (N)
4571 ("% attribute can only be applied to objects " &
4572 "of class - wide type");
4575 -- The prefix cannot be an incomplete type. However, references
4576 -- to 'Tag can be generated when expanding interface conversions,
4577 -- and this is legal.
4579 if Comes_From_Source (N) then
4580 Check_Not_Incomplete_Type;
4583 -- Set appropriate type
4585 Set_Etype (N, RTE (RE_Tag));
4592 when Attribute_Target_Name => Target_Name : declare
4593 TN : constant String := Sdefault.Target_Name.all;
4597 Check_Standard_Prefix;
4601 if TN (TL) = '/' or else TN (TL) = '\' then
4606 Make_String_Literal (Loc,
4607 Strval => TN (TN'First .. TL)));
4608 Analyze_And_Resolve (N, Standard_String);
4615 when Attribute_Terminated =>
4617 Set_Etype (N, Standard_Boolean);
4624 when Attribute_To_Address =>
4628 if Nkind (P) /= N_Identifier
4629 or else Chars (P) /= Name_System
4631 Error_Attr_P ("prefix of % attribute must be System");
4634 Generate_Reference (RTE (RE_Address), P);
4635 Analyze_And_Resolve (E1, Any_Integer);
4636 Set_Etype (N, RTE (RE_Address));
4642 when Attribute_To_Any =>
4644 Check_PolyORB_Attribute;
4645 Set_Etype (N, RTE (RE_Any));
4651 when Attribute_Truncation =>
4652 Check_Floating_Point_Type_1;
4653 Resolve (E1, P_Base_Type);
4654 Set_Etype (N, P_Base_Type);
4660 when Attribute_Type_Class =>
4663 Check_Not_Incomplete_Type;
4664 Set_Etype (N, RTE (RE_Type_Class));
4670 when Attribute_TypeCode =>
4672 Check_PolyORB_Attribute;
4673 Set_Etype (N, RTE (RE_TypeCode));
4679 when Attribute_Type_Key =>
4683 -- This processing belongs in Eval_Attribute ???
4686 function Type_Key return String_Id;
4687 -- A very preliminary implementation. For now, a signature
4688 -- consists of only the type name. This is clearly incomplete
4689 -- (e.g., adding a new field to a record type should change the
4690 -- type's Type_Key attribute).
4696 function Type_Key return String_Id is
4697 Full_Name : constant String_Id :=
4698 Fully_Qualified_Name_String (Entity (P));
4701 -- Copy all characters in Full_Name but the trailing NUL
4704 for J in 1 .. String_Length (Full_Name) - 1 loop
4705 Store_String_Char (Get_String_Char (Full_Name, Int (J)));
4708 Store_String_Chars ("'Type_Key");
4713 Rewrite (N, Make_String_Literal (Loc, Type_Key));
4716 Analyze_And_Resolve (N, Standard_String);
4722 when Attribute_UET_Address =>
4724 Check_Unit_Name (P);
4725 Set_Etype (N, RTE (RE_Address));
4727 -----------------------
4728 -- Unbiased_Rounding --
4729 -----------------------
4731 when Attribute_Unbiased_Rounding =>
4732 Check_Floating_Point_Type_1;
4733 Set_Etype (N, P_Base_Type);
4734 Resolve (E1, P_Base_Type);
4736 ----------------------
4737 -- Unchecked_Access --
4738 ----------------------
4740 when Attribute_Unchecked_Access =>
4741 if Comes_From_Source (N) then
4742 Check_Restriction (No_Unchecked_Access, N);
4745 Analyze_Access_Attribute;
4747 -------------------------
4748 -- Unconstrained_Array --
4749 -------------------------
4751 when Attribute_Unconstrained_Array =>
4754 Check_Not_Incomplete_Type;
4755 Set_Etype (N, Standard_Boolean);
4757 ------------------------------
4758 -- Universal_Literal_String --
4759 ------------------------------
4761 -- This is a GNAT specific attribute whose prefix must be a named
4762 -- number where the expression is either a single numeric literal,
4763 -- or a numeric literal immediately preceded by a minus sign. The
4764 -- result is equivalent to a string literal containing the text of
4765 -- the literal as it appeared in the source program with a possible
4766 -- leading minus sign.
4768 when Attribute_Universal_Literal_String => Universal_Literal_String :
4772 if not Is_Entity_Name (P)
4773 or else Ekind (Entity (P)) not in Named_Kind
4775 Error_Attr_P ("prefix for % attribute must be named number");
4782 Src : Source_Buffer_Ptr;
4785 Expr := Original_Node (Expression (Parent (Entity (P))));
4787 if Nkind (Expr) = N_Op_Minus then
4789 Expr := Original_Node (Right_Opnd (Expr));
4794 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4796 ("named number for % attribute must be simple literal", N);
4799 -- Build string literal corresponding to source literal text
4804 Store_String_Char (Get_Char_Code ('-'));
4808 Src := Source_Text (Get_Source_File_Index (S));
4810 while Src (S) /= ';' and then Src (S) /= ' ' loop
4811 Store_String_Char (Get_Char_Code (Src (S)));
4815 -- Now we rewrite the attribute with the string literal
4818 Make_String_Literal (Loc, End_String));
4822 end Universal_Literal_String;
4824 -------------------------
4825 -- Unrestricted_Access --
4826 -------------------------
4828 -- This is a GNAT specific attribute which is like Access except that
4829 -- all scope checks and checks for aliased views are omitted.
4831 when Attribute_Unrestricted_Access =>
4832 if Comes_From_Source (N) then
4833 Check_Restriction (No_Unchecked_Access, N);
4836 if Is_Entity_Name (P) then
4837 Set_Address_Taken (Entity (P));
4840 Analyze_Access_Attribute;
4846 when Attribute_Val => Val : declare
4849 Check_Discrete_Type;
4851 if Is_Boolean_Type (P_Type) then
4852 Error_Msg_Name_1 := Aname;
4853 Error_Msg_Name_2 := Chars (P_Type);
4854 Check_SPARK_Restriction
4855 ("attribute% is not allowed for type%", P);
4858 Resolve (E1, Any_Integer);
4859 Set_Etype (N, P_Base_Type);
4861 -- Note, we need a range check in general, but we wait for the
4862 -- Resolve call to do this, since we want to let Eval_Attribute
4863 -- have a chance to find an static illegality first!
4870 when Attribute_Valid =>
4873 -- Ignore check for object if we have a 'Valid reference generated
4874 -- by the expanded code, since in some cases valid checks can occur
4875 -- on items that are names, but are not objects (e.g. attributes).
4877 if Comes_From_Source (N) then
4878 Check_Object_Reference (P);
4881 if not Is_Scalar_Type (P_Type) then
4882 Error_Attr_P ("object for % attribute must be of scalar type");
4885 Set_Etype (N, Standard_Boolean);
4891 when Attribute_Value => Value :
4893 Check_SPARK_Restriction_On_Attribute;
4897 -- Case of enumeration type
4899 if Is_Enumeration_Type (P_Type) then
4900 Check_Restriction (No_Enumeration_Maps, N);
4902 -- Mark all enumeration literals as referenced, since the use of
4903 -- the Value attribute can implicitly reference any of the
4904 -- literals of the enumeration base type.
4907 Ent : Entity_Id := First_Literal (P_Base_Type);
4909 while Present (Ent) loop
4910 Set_Referenced (Ent);
4916 -- Set Etype before resolving expression because expansion of
4917 -- expression may require enclosing type. Note that the type
4918 -- returned by 'Value is the base type of the prefix type.
4920 Set_Etype (N, P_Base_Type);
4921 Validate_Non_Static_Attribute_Function_Call;
4928 when Attribute_Value_Size =>
4931 Check_Not_Incomplete_Type;
4932 Set_Etype (N, Universal_Integer);
4938 when Attribute_Version =>
4941 Set_Etype (N, RTE (RE_Version_String));
4947 when Attribute_Wchar_T_Size =>
4948 Standard_Attribute (Interfaces_Wchar_T_Size);
4954 when Attribute_Wide_Image => Wide_Image :
4956 Check_SPARK_Restriction_On_Attribute;
4958 Set_Etype (N, Standard_Wide_String);
4960 Resolve (E1, P_Base_Type);
4961 Validate_Non_Static_Attribute_Function_Call;
4964 ---------------------
4965 -- Wide_Wide_Image --
4966 ---------------------
4968 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
4971 Set_Etype (N, Standard_Wide_Wide_String);
4973 Resolve (E1, P_Base_Type);
4974 Validate_Non_Static_Attribute_Function_Call;
4975 end Wide_Wide_Image;
4981 when Attribute_Wide_Value => Wide_Value :
4983 Check_SPARK_Restriction_On_Attribute;
4987 -- Set Etype before resolving expression because expansion
4988 -- of expression may require enclosing type.
4990 Set_Etype (N, P_Type);
4991 Validate_Non_Static_Attribute_Function_Call;
4994 ---------------------
4995 -- Wide_Wide_Value --
4996 ---------------------
4998 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
5003 -- Set Etype before resolving expression because expansion
5004 -- of expression may require enclosing type.
5006 Set_Etype (N, P_Type);
5007 Validate_Non_Static_Attribute_Function_Call;
5008 end Wide_Wide_Value;
5010 ---------------------
5011 -- Wide_Wide_Width --
5012 ---------------------
5014 when Attribute_Wide_Wide_Width =>
5017 Set_Etype (N, Universal_Integer);
5023 when Attribute_Wide_Width =>
5024 Check_SPARK_Restriction_On_Attribute;
5027 Set_Etype (N, Universal_Integer);
5033 when Attribute_Width =>
5034 Check_SPARK_Restriction_On_Attribute;
5037 Set_Etype (N, Universal_Integer);
5043 when Attribute_Word_Size =>
5044 Standard_Attribute (System_Word_Size);
5050 when Attribute_Write =>
5052 Check_Stream_Attribute (TSS_Stream_Write);
5053 Set_Etype (N, Standard_Void_Type);
5054 Resolve (N, Standard_Void_Type);
5058 -- All errors raise Bad_Attribute, so that we get out before any further
5059 -- damage occurs when an error is detected (for example, if we check for
5060 -- one attribute expression, and the check succeeds, we want to be able
5061 -- to proceed securely assuming that an expression is in fact present.
5063 -- Note: we set the attribute analyzed in this case to prevent any
5064 -- attempt at reanalysis which could generate spurious error msgs.
5067 when Bad_Attribute =>
5069 Set_Etype (N, Any_Type);
5071 end Analyze_Attribute;
5073 --------------------
5074 -- Eval_Attribute --
5075 --------------------
5077 procedure Eval_Attribute (N : Node_Id) is
5078 Loc : constant Source_Ptr := Sloc (N);
5079 Aname : constant Name_Id := Attribute_Name (N);
5080 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
5081 P : constant Node_Id := Prefix (N);
5083 C_Type : constant Entity_Id := Etype (N);
5084 -- The type imposed by the context
5087 -- First expression, or Empty if none
5090 -- Second expression, or Empty if none
5092 P_Entity : Entity_Id;
5093 -- Entity denoted by prefix
5096 -- The type of the prefix
5098 P_Base_Type : Entity_Id;
5099 -- The base type of the prefix type
5101 P_Root_Type : Entity_Id;
5102 -- The root type of the prefix type
5105 -- True if the result is Static. This is set by the general processing
5106 -- to true if the prefix is static, and all expressions are static. It
5107 -- can be reset as processing continues for particular attributes
5109 Lo_Bound, Hi_Bound : Node_Id;
5110 -- Expressions for low and high bounds of type or array index referenced
5111 -- by First, Last, or Length attribute for array, set by Set_Bounds.
5114 -- Constraint error node used if we have an attribute reference has
5115 -- an argument that raises a constraint error. In this case we replace
5116 -- the attribute with a raise constraint_error node. This is important
5117 -- processing, since otherwise gigi might see an attribute which it is
5118 -- unprepared to deal with.
5120 procedure Check_Concurrent_Discriminant (Bound : Node_Id);
5121 -- If Bound is a reference to a discriminant of a task or protected type
5122 -- occurring within the object's body, rewrite attribute reference into
5123 -- a reference to the corresponding discriminal. Use for the expansion
5124 -- of checks against bounds of entry family index subtypes.
5126 procedure Check_Expressions;
5127 -- In case where the attribute is not foldable, the expressions, if
5128 -- any, of the attribute, are in a non-static context. This procedure
5129 -- performs the required additional checks.
5131 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
5132 -- Determines if the given type has compile time known bounds. Note
5133 -- that we enter the case statement even in cases where the prefix
5134 -- type does NOT have known bounds, so it is important to guard any
5135 -- attempt to evaluate both bounds with a call to this function.
5137 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
5138 -- This procedure is called when the attribute N has a non-static
5139 -- but compile time known value given by Val. It includes the
5140 -- necessary checks for out of range values.
5142 function Fore_Value return Nat;
5143 -- Computes the Fore value for the current attribute prefix, which is
5144 -- known to be a static fixed-point type. Used by Fore and Width.
5146 function Mantissa return Uint;
5147 -- Returns the Mantissa value for the prefix type
5149 procedure Set_Bounds;
5150 -- Used for First, Last and Length attributes applied to an array or
5151 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
5152 -- and high bound expressions for the index referenced by the attribute
5153 -- designator (i.e. the first index if no expression is present, and
5154 -- the N'th index if the value N is present as an expression). Also
5155 -- used for First and Last of scalar types. Static is reset to False
5156 -- if the type or index type is not statically constrained.
5158 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
5159 -- Verify that the prefix of a potentially static array attribute
5160 -- satisfies the conditions of 4.9 (14).
5162 -----------------------------------
5163 -- Check_Concurrent_Discriminant --
5164 -----------------------------------
5166 procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
5168 -- The concurrent (task or protected) type
5171 if Nkind (Bound) = N_Identifier
5172 and then Ekind (Entity (Bound)) = E_Discriminant
5173 and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
5175 Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
5177 if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
5179 -- Find discriminant of original concurrent type, and use
5180 -- its current discriminal, which is the renaming within
5181 -- the task/protected body.
5185 (Find_Body_Discriminal (Entity (Bound)), Loc));
5188 end Check_Concurrent_Discriminant;
5190 -----------------------
5191 -- Check_Expressions --
5192 -----------------------
5194 procedure Check_Expressions is
5198 while Present (E) loop
5199 Check_Non_Static_Context (E);
5202 end Check_Expressions;
5204 ----------------------------------
5205 -- Compile_Time_Known_Attribute --
5206 ----------------------------------
5208 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
5209 T : constant Entity_Id := Etype (N);
5212 Fold_Uint (N, Val, False);
5214 -- Check that result is in bounds of the type if it is static
5216 if Is_In_Range (N, T, Assume_Valid => False) then
5219 elsif Is_Out_Of_Range (N, T) then
5220 Apply_Compile_Time_Constraint_Error
5221 (N, "value not in range of}?", CE_Range_Check_Failed);
5223 elsif not Range_Checks_Suppressed (T) then
5224 Enable_Range_Check (N);
5227 Set_Do_Range_Check (N, False);
5229 end Compile_Time_Known_Attribute;
5231 -------------------------------
5232 -- Compile_Time_Known_Bounds --
5233 -------------------------------
5235 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
5238 Compile_Time_Known_Value (Type_Low_Bound (Typ))
5240 Compile_Time_Known_Value (Type_High_Bound (Typ));
5241 end Compile_Time_Known_Bounds;
5247 -- Note that the Fore calculation is based on the actual values
5248 -- of the bounds, and does not take into account possible rounding.
5250 function Fore_Value return Nat is
5251 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
5252 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
5253 Small : constant Ureal := Small_Value (P_Type);
5254 Lo_Real : constant Ureal := Lo * Small;
5255 Hi_Real : constant Ureal := Hi * Small;
5260 -- Bounds are given in terms of small units, so first compute
5261 -- proper values as reals.
5263 T := UR_Max (abs Lo_Real, abs Hi_Real);
5266 -- Loop to compute proper value if more than one digit required
5268 while T >= Ureal_10 loop
5280 -- Table of mantissa values accessed by function Computed using
5283 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5285 -- where D is T'Digits (RM83 3.5.7)
5287 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5329 function Mantissa return Uint is
5332 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5339 procedure Set_Bounds is
5345 -- For a string literal subtype, we have to construct the bounds.
5346 -- Valid Ada code never applies attributes to string literals, but
5347 -- it is convenient to allow the expander to generate attribute
5348 -- references of this type (e.g. First and Last applied to a string
5351 -- Note that the whole point of the E_String_Literal_Subtype is to
5352 -- avoid this construction of bounds, but the cases in which we
5353 -- have to materialize them are rare enough that we don't worry!
5355 -- The low bound is simply the low bound of the base type. The
5356 -- high bound is computed from the length of the string and this
5359 if Ekind (P_Type) = E_String_Literal_Subtype then
5360 Ityp := Etype (First_Index (Base_Type (P_Type)));
5361 Lo_Bound := Type_Low_Bound (Ityp);
5364 Make_Integer_Literal (Sloc (P),
5366 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5368 Set_Parent (Hi_Bound, P);
5369 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5372 -- For non-array case, just get bounds of scalar type
5374 elsif Is_Scalar_Type (P_Type) then
5377 -- For a fixed-point type, we must freeze to get the attributes
5378 -- of the fixed-point type set now so we can reference them.
5380 if Is_Fixed_Point_Type (P_Type)
5381 and then not Is_Frozen (Base_Type (P_Type))
5382 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5383 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5385 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5388 -- For array case, get type of proper index
5394 Ndim := UI_To_Int (Expr_Value (E1));
5397 Indx := First_Index (P_Type);
5398 for J in 1 .. Ndim - 1 loop
5402 -- If no index type, get out (some other error occurred, and
5403 -- we don't have enough information to complete the job!)
5411 Ityp := Etype (Indx);
5414 -- A discrete range in an index constraint is allowed to be a
5415 -- subtype indication. This is syntactically a pain, but should
5416 -- not propagate to the entity for the corresponding index subtype.
5417 -- After checking that the subtype indication is legal, the range
5418 -- of the subtype indication should be transfered to the entity.
5419 -- The attributes for the bounds should remain the simple retrievals
5420 -- that they are now.
5422 Lo_Bound := Type_Low_Bound (Ityp);
5423 Hi_Bound := Type_High_Bound (Ityp);
5425 if not Is_Static_Subtype (Ityp) then
5430 -------------------------------
5431 -- Statically_Denotes_Entity --
5432 -------------------------------
5434 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5438 if not Is_Entity_Name (N) then
5445 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5446 or else Statically_Denotes_Entity (Renamed_Object (E));
5447 end Statically_Denotes_Entity;
5449 -- Start of processing for Eval_Attribute
5452 -- No folding in spec expression that comes from source where the prefix
5453 -- is an unfrozen entity. This avoids premature folding in cases like:
5455 -- procedure DefExprAnal is
5456 -- type R is new Integer;
5457 -- procedure P (Arg : Integer := R'Size);
5458 -- for R'Size use 64;
5459 -- procedure P (Arg : Integer := R'Size) is
5461 -- Put_Line (Arg'Img);
5467 -- which should print 64 rather than 32. The exclusion of non-source
5468 -- constructs from this test comes from some internal usage in packed
5469 -- arrays, which otherwise fails, could use more analysis perhaps???
5471 -- We do however go ahead with generic actual types, otherwise we get
5472 -- some regressions, probably these types should be frozen anyway???
5474 if In_Spec_Expression
5475 and then Comes_From_Source (N)
5476 and then not (Is_Entity_Name (P)
5478 (Is_Frozen (Entity (P))
5479 or else (Is_Type (Entity (P))
5481 Is_Generic_Actual_Type (Entity (P)))))
5486 -- Acquire first two expressions (at the moment, no attributes take more
5487 -- than two expressions in any case).
5489 if Present (Expressions (N)) then
5490 E1 := First (Expressions (N));
5497 -- Special processing for Enabled attribute. This attribute has a very
5498 -- special prefix, and the easiest way to avoid lots of special checks
5499 -- to protect this special prefix from causing trouble is to deal with
5500 -- this attribute immediately and be done with it.
5502 if Id = Attribute_Enabled then
5504 -- We skip evaluation if the expander is not active. This is not just
5505 -- an optimization. It is of key importance that we not rewrite the
5506 -- attribute in a generic template, since we want to pick up the
5507 -- setting of the check in the instance, and testing expander active
5508 -- is as easy way of doing this as any.
5510 if Expander_Active then
5512 C : constant Check_Id := Get_Check_Id (Chars (P));
5517 if C in Predefined_Check_Id then
5518 R := Scope_Suppress (C);
5520 R := Is_Check_Suppressed (Empty, C);
5524 R := Is_Check_Suppressed (Entity (E1), C);
5528 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5530 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5538 -- Special processing for cases where the prefix is an object. For
5539 -- this purpose, a string literal counts as an object (attributes
5540 -- of string literals can only appear in generated code).
5542 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5544 -- For Component_Size, the prefix is an array object, and we apply
5545 -- the attribute to the type of the object. This is allowed for
5546 -- both unconstrained and constrained arrays, since the bounds
5547 -- have no influence on the value of this attribute.
5549 if Id = Attribute_Component_Size then
5550 P_Entity := Etype (P);
5552 -- For First and Last, the prefix is an array object, and we apply
5553 -- the attribute to the type of the array, but we need a constrained
5554 -- type for this, so we use the actual subtype if available.
5556 elsif Id = Attribute_First
5560 Id = Attribute_Length
5563 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5566 if Present (AS) and then Is_Constrained (AS) then
5569 -- If we have an unconstrained type we cannot fold
5577 -- For Size, give size of object if available, otherwise we
5578 -- cannot fold Size.
5580 elsif Id = Attribute_Size then
5581 if Is_Entity_Name (P)
5582 and then Known_Esize (Entity (P))
5584 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5592 -- For Alignment, give size of object if available, otherwise we
5593 -- cannot fold Alignment.
5595 elsif Id = Attribute_Alignment then
5596 if Is_Entity_Name (P)
5597 and then Known_Alignment (Entity (P))
5599 Fold_Uint (N, Alignment (Entity (P)), False);
5607 -- No other attributes for objects are folded
5614 -- Cases where P is not an object. Cannot do anything if P is
5615 -- not the name of an entity.
5617 elsif not Is_Entity_Name (P) then
5621 -- Otherwise get prefix entity
5624 P_Entity := Entity (P);
5627 -- At this stage P_Entity is the entity to which the attribute
5628 -- is to be applied. This is usually simply the entity of the
5629 -- prefix, except in some cases of attributes for objects, where
5630 -- as described above, we apply the attribute to the object type.
5632 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5633 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5634 -- Note we allow non-static non-generic types at this stage as further
5637 if Is_Type (P_Entity)
5638 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5639 and then (not Is_Generic_Type (P_Entity))
5643 -- Second foldable possibility is an array object (RM 4.9(8))
5645 elsif (Ekind (P_Entity) = E_Variable
5647 Ekind (P_Entity) = E_Constant)
5648 and then Is_Array_Type (Etype (P_Entity))
5649 and then (not Is_Generic_Type (Etype (P_Entity)))
5651 P_Type := Etype (P_Entity);
5653 -- If the entity is an array constant with an unconstrained nominal
5654 -- subtype then get the type from the initial value. If the value has
5655 -- been expanded into assignments, there is no expression and the
5656 -- attribute reference remains dynamic.
5658 -- We could do better here and retrieve the type ???
5660 if Ekind (P_Entity) = E_Constant
5661 and then not Is_Constrained (P_Type)
5663 if No (Constant_Value (P_Entity)) then
5666 P_Type := Etype (Constant_Value (P_Entity));
5670 -- Definite must be folded if the prefix is not a generic type,
5671 -- that is to say if we are within an instantiation. Same processing
5672 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5673 -- Has_Tagged_Value, and Unconstrained_Array.
5675 elsif (Id = Attribute_Definite
5677 Id = Attribute_Has_Access_Values
5679 Id = Attribute_Has_Discriminants
5681 Id = Attribute_Has_Tagged_Values
5683 Id = Attribute_Type_Class
5685 Id = Attribute_Unconstrained_Array
5687 Id = Attribute_Max_Alignment_For_Allocation)
5688 and then not Is_Generic_Type (P_Entity)
5692 -- We can fold 'Size applied to a type if the size is known (as happens
5693 -- for a size from an attribute definition clause). At this stage, this
5694 -- can happen only for types (e.g. record types) for which the size is
5695 -- always non-static. We exclude generic types from consideration (since
5696 -- they have bogus sizes set within templates).
5698 elsif Id = Attribute_Size
5699 and then Is_Type (P_Entity)
5700 and then (not Is_Generic_Type (P_Entity))
5701 and then Known_Static_RM_Size (P_Entity)
5703 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5706 -- We can fold 'Alignment applied to a type if the alignment is known
5707 -- (as happens for an alignment from an attribute definition clause).
5708 -- At this stage, this can happen only for types (e.g. record
5709 -- types) for which the size is always non-static. We exclude
5710 -- generic types from consideration (since they have bogus
5711 -- sizes set within templates).
5713 elsif Id = Attribute_Alignment
5714 and then Is_Type (P_Entity)
5715 and then (not Is_Generic_Type (P_Entity))
5716 and then Known_Alignment (P_Entity)
5718 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5721 -- If this is an access attribute that is known to fail accessibility
5722 -- check, rewrite accordingly.
5724 elsif Attribute_Name (N) = Name_Access
5725 and then Raises_Constraint_Error (N)
5728 Make_Raise_Program_Error (Loc,
5729 Reason => PE_Accessibility_Check_Failed));
5730 Set_Etype (N, C_Type);
5733 -- No other cases are foldable (they certainly aren't static, and at
5734 -- the moment we don't try to fold any cases other than these three).
5741 -- If either attribute or the prefix is Any_Type, then propagate
5742 -- Any_Type to the result and don't do anything else at all.
5744 if P_Type = Any_Type
5745 or else (Present (E1) and then Etype (E1) = Any_Type)
5746 or else (Present (E2) and then Etype (E2) = Any_Type)
5748 Set_Etype (N, Any_Type);
5752 -- Scalar subtype case. We have not yet enforced the static requirement
5753 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5754 -- of non-static attribute references (e.g. S'Digits for a non-static
5755 -- floating-point type, which we can compute at compile time).
5757 -- Note: this folding of non-static attributes is not simply a case of
5758 -- optimization. For many of the attributes affected, Gigi cannot handle
5759 -- the attribute and depends on the front end having folded them away.
5761 -- Note: although we don't require staticness at this stage, we do set
5762 -- the Static variable to record the staticness, for easy reference by
5763 -- those attributes where it matters (e.g. Succ and Pred), and also to
5764 -- be used to ensure that non-static folded things are not marked as
5765 -- being static (a check that is done right at the end).
5767 P_Root_Type := Root_Type (P_Type);
5768 P_Base_Type := Base_Type (P_Type);
5770 -- If the root type or base type is generic, then we cannot fold. This
5771 -- test is needed because subtypes of generic types are not always
5772 -- marked as being generic themselves (which seems odd???)
5774 if Is_Generic_Type (P_Root_Type)
5775 or else Is_Generic_Type (P_Base_Type)
5780 if Is_Scalar_Type (P_Type) then
5781 Static := Is_OK_Static_Subtype (P_Type);
5783 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5784 -- since we can't do anything with unconstrained arrays. In addition,
5785 -- only the First, Last and Length attributes are possibly static.
5787 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5788 -- Type_Class, and Unconstrained_Array are again exceptions, because
5789 -- they apply as well to unconstrained types.
5791 -- In addition Component_Size is an exception since it is possibly
5792 -- foldable, even though it is never static, and it does apply to
5793 -- unconstrained arrays. Furthermore, it is essential to fold this
5794 -- in the packed case, since otherwise the value will be incorrect.
5796 elsif Id = Attribute_Definite
5798 Id = Attribute_Has_Access_Values
5800 Id = Attribute_Has_Discriminants
5802 Id = Attribute_Has_Tagged_Values
5804 Id = Attribute_Type_Class
5806 Id = Attribute_Unconstrained_Array
5808 Id = Attribute_Component_Size
5812 elsif Id /= Attribute_Max_Alignment_For_Allocation then
5813 if not Is_Constrained (P_Type)
5814 or else (Id /= Attribute_First and then
5815 Id /= Attribute_Last and then
5816 Id /= Attribute_Length)
5822 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5823 -- scalar case, we hold off on enforcing staticness, since there are
5824 -- cases which we can fold at compile time even though they are not
5825 -- static (e.g. 'Length applied to a static index, even though other
5826 -- non-static indexes make the array type non-static). This is only
5827 -- an optimization, but it falls out essentially free, so why not.
5828 -- Again we compute the variable Static for easy reference later
5829 -- (note that no array attributes are static in Ada 83).
5831 -- We also need to set Static properly for subsequent legality checks
5832 -- which might otherwise accept non-static constants in contexts
5833 -- where they are not legal.
5835 Static := Ada_Version >= Ada_95
5836 and then Statically_Denotes_Entity (P);
5842 N := First_Index (P_Type);
5844 -- The expression is static if the array type is constrained
5845 -- by given bounds, and not by an initial expression. Constant
5846 -- strings are static in any case.
5848 if Root_Type (P_Type) /= Standard_String then
5850 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
5853 while Present (N) loop
5854 Static := Static and then Is_Static_Subtype (Etype (N));
5856 -- If however the index type is generic, or derived from
5857 -- one, attributes cannot be folded.
5859 if Is_Generic_Type (Root_Type (Etype (N)))
5860 and then Id /= Attribute_Component_Size
5870 -- Check any expressions that are present. Note that these expressions,
5871 -- depending on the particular attribute type, are either part of the
5872 -- attribute designator, or they are arguments in a case where the
5873 -- attribute reference returns a function. In the latter case, the
5874 -- rule in (RM 4.9(22)) applies and in particular requires the type
5875 -- of the expressions to be scalar in order for the attribute to be
5876 -- considered to be static.
5883 while Present (E) loop
5885 -- If expression is not static, then the attribute reference
5886 -- result certainly cannot be static.
5888 if not Is_Static_Expression (E) then
5892 -- If the result is not known at compile time, or is not of
5893 -- a scalar type, then the result is definitely not static,
5894 -- so we can quit now.
5896 if not Compile_Time_Known_Value (E)
5897 or else not Is_Scalar_Type (Etype (E))
5899 -- An odd special case, if this is a Pos attribute, this
5900 -- is where we need to apply a range check since it does
5901 -- not get done anywhere else.
5903 if Id = Attribute_Pos then
5904 if Is_Integer_Type (Etype (E)) then
5905 Apply_Range_Check (E, Etype (N));
5912 -- If the expression raises a constraint error, then so does
5913 -- the attribute reference. We keep going in this case because
5914 -- we are still interested in whether the attribute reference
5915 -- is static even if it is not static.
5917 elsif Raises_Constraint_Error (E) then
5918 Set_Raises_Constraint_Error (N);
5924 if Raises_Constraint_Error (Prefix (N)) then
5929 -- Deal with the case of a static attribute reference that raises
5930 -- constraint error. The Raises_Constraint_Error flag will already
5931 -- have been set, and the Static flag shows whether the attribute
5932 -- reference is static. In any case we certainly can't fold such an
5933 -- attribute reference.
5935 -- Note that the rewriting of the attribute node with the constraint
5936 -- error node is essential in this case, because otherwise Gigi might
5937 -- blow up on one of the attributes it never expects to see.
5939 -- The constraint_error node must have the type imposed by the context,
5940 -- to avoid spurious errors in the enclosing expression.
5942 if Raises_Constraint_Error (N) then
5944 Make_Raise_Constraint_Error (Sloc (N),
5945 Reason => CE_Range_Check_Failed);
5946 Set_Etype (CE_Node, Etype (N));
5947 Set_Raises_Constraint_Error (CE_Node);
5949 Rewrite (N, Relocate_Node (CE_Node));
5950 Set_Is_Static_Expression (N, Static);
5954 -- At this point we have a potentially foldable attribute reference.
5955 -- If Static is set, then the attribute reference definitely obeys
5956 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
5957 -- folded. If Static is not set, then the attribute may or may not
5958 -- be foldable, and the individual attribute processing routines
5959 -- test Static as required in cases where it makes a difference.
5961 -- In the case where Static is not set, we do know that all the
5962 -- expressions present are at least known at compile time (we
5963 -- assumed above that if this was not the case, then there was
5964 -- no hope of static evaluation). However, we did not require
5965 -- that the bounds of the prefix type be compile time known,
5966 -- let alone static). That's because there are many attributes
5967 -- that can be computed at compile time on non-static subtypes,
5968 -- even though such references are not static expressions.
5976 when Attribute_Adjacent =>
5979 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5985 when Attribute_Aft =>
5986 Fold_Uint (N, Aft_Value (P_Type), True);
5992 when Attribute_Alignment => Alignment_Block : declare
5993 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5996 -- Fold if alignment is set and not otherwise
5998 if Known_Alignment (P_TypeA) then
5999 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
6001 end Alignment_Block;
6007 -- Can only be folded in No_Ast_Handler case
6009 when Attribute_AST_Entry =>
6010 if not Is_AST_Entry (P_Entity) then
6012 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
6021 -- Bit can never be folded
6023 when Attribute_Bit =>
6030 -- Body_version can never be static
6032 when Attribute_Body_Version =>
6039 when Attribute_Ceiling =>
6041 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
6043 --------------------
6044 -- Component_Size --
6045 --------------------
6047 when Attribute_Component_Size =>
6048 if Known_Static_Component_Size (P_Type) then
6049 Fold_Uint (N, Component_Size (P_Type), False);
6056 when Attribute_Compose =>
6059 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
6066 -- Constrained is never folded for now, there may be cases that
6067 -- could be handled at compile time. To be looked at later.
6069 when Attribute_Constrained =>
6076 when Attribute_Copy_Sign =>
6079 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6085 when Attribute_Definite =>
6086 Rewrite (N, New_Occurrence_Of (
6087 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
6088 Analyze_And_Resolve (N, Standard_Boolean);
6094 when Attribute_Delta =>
6095 Fold_Ureal (N, Delta_Value (P_Type), True);
6101 when Attribute_Denorm =>
6103 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
6109 when Attribute_Digits =>
6110 Fold_Uint (N, Digits_Value (P_Type), True);
6116 when Attribute_Emax =>
6118 -- Ada 83 attribute is defined as (RM83 3.5.8)
6120 -- T'Emax = 4 * T'Mantissa
6122 Fold_Uint (N, 4 * Mantissa, True);
6128 when Attribute_Enum_Rep =>
6130 -- For an enumeration type with a non-standard representation use
6131 -- the Enumeration_Rep field of the proper constant. Note that this
6132 -- will not work for types Character/Wide_[Wide-]Character, since no
6133 -- real entities are created for the enumeration literals, but that
6134 -- does not matter since these two types do not have non-standard
6135 -- representations anyway.
6137 if Is_Enumeration_Type (P_Type)
6138 and then Has_Non_Standard_Rep (P_Type)
6140 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
6142 -- For enumeration types with standard representations and all
6143 -- other cases (i.e. all integer and modular types), Enum_Rep
6144 -- is equivalent to Pos.
6147 Fold_Uint (N, Expr_Value (E1), Static);
6154 when Attribute_Enum_Val => Enum_Val : declare
6158 -- We have something like Enum_Type'Enum_Val (23), so search for a
6159 -- corresponding value in the list of Enum_Rep values for the type.
6161 Lit := First_Literal (P_Base_Type);
6163 if Enumeration_Rep (Lit) = Expr_Value (E1) then
6164 Fold_Uint (N, Enumeration_Pos (Lit), Static);
6171 Apply_Compile_Time_Constraint_Error
6172 (N, "no representation value matches",
6173 CE_Range_Check_Failed,
6174 Warn => not Static);
6184 when Attribute_Epsilon =>
6186 -- Ada 83 attribute is defined as (RM83 3.5.8)
6188 -- T'Epsilon = 2.0**(1 - T'Mantissa)
6190 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
6196 when Attribute_Exponent =>
6198 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
6204 when Attribute_First => First_Attr :
6208 if Compile_Time_Known_Value (Lo_Bound) then
6209 if Is_Real_Type (P_Type) then
6210 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
6212 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
6216 Check_Concurrent_Discriminant (Lo_Bound);
6224 when Attribute_Fixed_Value =>
6231 when Attribute_Floor =>
6233 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
6239 when Attribute_Fore =>
6240 if Compile_Time_Known_Bounds (P_Type) then
6241 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
6248 when Attribute_Fraction =>
6250 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
6252 -----------------------
6253 -- Has_Access_Values --
6254 -----------------------
6256 when Attribute_Has_Access_Values =>
6257 Rewrite (N, New_Occurrence_Of
6258 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
6259 Analyze_And_Resolve (N, Standard_Boolean);
6261 -----------------------
6262 -- Has_Discriminants --
6263 -----------------------
6265 when Attribute_Has_Discriminants =>
6266 Rewrite (N, New_Occurrence_Of (
6267 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
6268 Analyze_And_Resolve (N, Standard_Boolean);
6270 -----------------------
6271 -- Has_Tagged_Values --
6272 -----------------------
6274 when Attribute_Has_Tagged_Values =>
6275 Rewrite (N, New_Occurrence_Of
6276 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
6277 Analyze_And_Resolve (N, Standard_Boolean);
6283 when Attribute_Identity =>
6290 -- Image is a scalar attribute, but is never static, because it is
6291 -- not a static function (having a non-scalar argument (RM 4.9(22))
6292 -- However, we can constant-fold the image of an enumeration literal
6293 -- if names are available.
6295 when Attribute_Image =>
6296 if Is_Entity_Name (E1)
6297 and then Ekind (Entity (E1)) = E_Enumeration_Literal
6298 and then not Discard_Names (First_Subtype (Etype (E1)))
6299 and then not Global_Discard_Names
6302 Lit : constant Entity_Id := Entity (E1);
6306 Get_Unqualified_Decoded_Name_String (Chars (Lit));
6307 Set_Casing (All_Upper_Case);
6308 Store_String_Chars (Name_Buffer (1 .. Name_Len));
6310 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
6311 Analyze_And_Resolve (N, Standard_String);
6312 Set_Is_Static_Expression (N, False);
6320 -- Img is a scalar attribute, but is never static, because it is
6321 -- not a static function (having a non-scalar argument (RM 4.9(22))
6323 when Attribute_Img =>
6330 -- We never try to fold Integer_Value (though perhaps we could???)
6332 when Attribute_Integer_Value =>
6339 -- Invalid_Value is a scalar attribute that is never static, because
6340 -- the value is by design out of range.
6342 when Attribute_Invalid_Value =>
6349 when Attribute_Large =>
6351 -- For fixed-point, we use the identity:
6353 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6355 if Is_Fixed_Point_Type (P_Type) then
6357 Make_Op_Multiply (Loc,
6359 Make_Op_Subtract (Loc,
6363 Make_Real_Literal (Loc, Ureal_2),
6365 Make_Attribute_Reference (Loc,
6367 Attribute_Name => Name_Mantissa)),
6368 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6371 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6373 Analyze_And_Resolve (N, C_Type);
6375 -- Floating-point (Ada 83 compatibility)
6378 -- Ada 83 attribute is defined as (RM83 3.5.8)
6380 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6384 -- T'Emax = 4 * T'Mantissa
6387 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6395 when Attribute_Last => Last :
6399 if Compile_Time_Known_Value (Hi_Bound) then
6400 if Is_Real_Type (P_Type) then
6401 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6403 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6407 Check_Concurrent_Discriminant (Hi_Bound);
6415 when Attribute_Leading_Part =>
6417 Eval_Fat.Leading_Part
6418 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6424 when Attribute_Length => Length : declare
6428 -- If any index type is a formal type, or derived from one, the
6429 -- bounds are not static. Treating them as static can produce
6430 -- spurious warnings or improper constant folding.
6432 Ind := First_Index (P_Type);
6433 while Present (Ind) loop
6434 if Is_Generic_Type (Root_Type (Etype (Ind))) then
6443 -- For two compile time values, we can compute length
6445 if Compile_Time_Known_Value (Lo_Bound)
6446 and then Compile_Time_Known_Value (Hi_Bound)
6449 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6453 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6454 -- comparable, and we can figure out the difference between them.
6457 Diff : aliased Uint;
6461 Compile_Time_Compare
6462 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6465 Fold_Uint (N, Uint_1, False);
6468 Fold_Uint (N, Uint_0, False);
6471 if Diff /= No_Uint then
6472 Fold_Uint (N, Diff + 1, False);
6485 when Attribute_Machine =>
6488 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6495 when Attribute_Machine_Emax =>
6496 Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
6502 when Attribute_Machine_Emin =>
6503 Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
6505 ----------------------
6506 -- Machine_Mantissa --
6507 ----------------------
6509 when Attribute_Machine_Mantissa =>
6510 Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
6512 -----------------------
6513 -- Machine_Overflows --
6514 -----------------------
6516 when Attribute_Machine_Overflows =>
6518 -- Always true for fixed-point
6520 if Is_Fixed_Point_Type (P_Type) then
6521 Fold_Uint (N, True_Value, True);
6523 -- Floating point case
6527 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6535 when Attribute_Machine_Radix =>
6536 if Is_Fixed_Point_Type (P_Type) then
6537 if Is_Decimal_Fixed_Point_Type (P_Type)
6538 and then Machine_Radix_10 (P_Type)
6540 Fold_Uint (N, Uint_10, True);
6542 Fold_Uint (N, Uint_2, True);
6545 -- All floating-point type always have radix 2
6548 Fold_Uint (N, Uint_2, True);
6551 ----------------------
6552 -- Machine_Rounding --
6553 ----------------------
6555 -- Note: for the folding case, it is fine to treat Machine_Rounding
6556 -- exactly the same way as Rounding, since this is one of the allowed
6557 -- behaviors, and performance is not an issue here. It might be a bit
6558 -- better to give the same result as it would give at run time, even
6559 -- though the non-determinism is certainly permitted.
6561 when Attribute_Machine_Rounding =>
6563 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6565 --------------------
6566 -- Machine_Rounds --
6567 --------------------
6569 when Attribute_Machine_Rounds =>
6571 -- Always False for fixed-point
6573 if Is_Fixed_Point_Type (P_Type) then
6574 Fold_Uint (N, False_Value, True);
6576 -- Else yield proper floating-point result
6580 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6587 -- Note: Machine_Size is identical to Object_Size
6589 when Attribute_Machine_Size => Machine_Size : declare
6590 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6593 if Known_Esize (P_TypeA) then
6594 Fold_Uint (N, Esize (P_TypeA), True);
6602 when Attribute_Mantissa =>
6604 -- Fixed-point mantissa
6606 if Is_Fixed_Point_Type (P_Type) then
6608 -- Compile time foldable case
6610 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6612 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6614 -- The calculation of the obsolete Ada 83 attribute Mantissa
6615 -- is annoying, because of AI00143, quoted here:
6617 -- !question 84-01-10
6619 -- Consider the model numbers for F:
6621 -- type F is delta 1.0 range -7.0 .. 8.0;
6623 -- The wording requires that F'MANTISSA be the SMALLEST
6624 -- integer number for which each bound of the specified
6625 -- range is either a model number or lies at most small
6626 -- distant from a model number. This means F'MANTISSA
6627 -- is required to be 3 since the range -7.0 .. 7.0 fits
6628 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6629 -- number, namely, 7. Is this analysis correct? Note that
6630 -- this implies the upper bound of the range is not
6631 -- represented as a model number.
6633 -- !response 84-03-17
6635 -- The analysis is correct. The upper and lower bounds for
6636 -- a fixed point type can lie outside the range of model
6647 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6648 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6649 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6650 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6652 -- If the Bound is exactly a model number, i.e. a multiple
6653 -- of Small, then we back it off by one to get the integer
6654 -- value that must be representable.
6656 if Small_Value (P_Type) * Max_Man = Bound then
6657 Max_Man := Max_Man - 1;
6660 -- Now find corresponding size = Mantissa value
6663 while 2 ** Siz < Max_Man loop
6667 Fold_Uint (N, Siz, True);
6671 -- The case of dynamic bounds cannot be evaluated at compile
6672 -- time. Instead we use a runtime routine (see Exp_Attr).
6677 -- Floating-point Mantissa
6680 Fold_Uint (N, Mantissa, True);
6687 when Attribute_Max => Max :
6689 if Is_Real_Type (P_Type) then
6691 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6693 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6697 ----------------------------------
6698 -- Max_Alignment_For_Allocation --
6699 ----------------------------------
6701 -- Max_Alignment_For_Allocation is usually the Alignment. However,
6702 -- arrays are allocated with dope, so we need to take into account both
6703 -- the alignment of the array, which comes from the component alignment,
6704 -- and the alignment of the dope. Also, if the alignment is unknown, we
6705 -- use the max (it's OK to be pessimistic).
6707 when Attribute_Max_Alignment_For_Allocation =>
6709 A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
6711 if Known_Alignment (P_Type) and then
6712 (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
6714 A := Alignment (P_Type);
6717 Fold_Uint (N, A, Static);
6720 ----------------------------------
6721 -- Max_Size_In_Storage_Elements --
6722 ----------------------------------
6724 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6725 -- Storage_Unit boundary. We can fold any cases for which the size
6726 -- is known by the front end.
6728 when Attribute_Max_Size_In_Storage_Elements =>
6729 if Known_Esize (P_Type) then
6731 (Esize (P_Type) + System_Storage_Unit - 1) /
6732 System_Storage_Unit,
6736 --------------------
6737 -- Mechanism_Code --
6738 --------------------
6740 when Attribute_Mechanism_Code =>
6744 Mech : Mechanism_Type;
6748 Mech := Mechanism (P_Entity);
6751 Val := UI_To_Int (Expr_Value (E1));
6753 Formal := First_Formal (P_Entity);
6754 for J in 1 .. Val - 1 loop
6755 Next_Formal (Formal);
6757 Mech := Mechanism (Formal);
6761 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6769 when Attribute_Min => Min :
6771 if Is_Real_Type (P_Type) then
6773 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6776 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6784 when Attribute_Mod =>
6786 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6792 when Attribute_Model =>
6794 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
6800 when Attribute_Model_Emin =>
6801 Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
6807 when Attribute_Model_Epsilon =>
6808 Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
6810 --------------------
6811 -- Model_Mantissa --
6812 --------------------
6814 when Attribute_Model_Mantissa =>
6815 Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
6821 when Attribute_Model_Small =>
6822 Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
6828 when Attribute_Modulus =>
6829 Fold_Uint (N, Modulus (P_Type), True);
6831 --------------------
6832 -- Null_Parameter --
6833 --------------------
6835 -- Cannot fold, we know the value sort of, but the whole point is
6836 -- that there is no way to talk about this imaginary value except
6837 -- by using the attribute, so we leave it the way it is.
6839 when Attribute_Null_Parameter =>
6846 -- The Object_Size attribute for a type returns the Esize of the
6847 -- type and can be folded if this value is known.
6849 when Attribute_Object_Size => Object_Size : declare
6850 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6853 if Known_Esize (P_TypeA) then
6854 Fold_Uint (N, Esize (P_TypeA), True);
6858 -------------------------
6859 -- Passed_By_Reference --
6860 -------------------------
6862 -- Scalar types are never passed by reference
6864 when Attribute_Passed_By_Reference =>
6865 Fold_Uint (N, False_Value, True);
6871 when Attribute_Pos =>
6872 Fold_Uint (N, Expr_Value (E1), True);
6878 when Attribute_Pred => Pred :
6880 -- Floating-point case
6882 if Is_Floating_Point_Type (P_Type) then
6884 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
6888 elsif Is_Fixed_Point_Type (P_Type) then
6890 Expr_Value_R (E1) - Small_Value (P_Type), True);
6892 -- Modular integer case (wraps)
6894 elsif Is_Modular_Integer_Type (P_Type) then
6895 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
6897 -- Other scalar cases
6900 pragma Assert (Is_Scalar_Type (P_Type));
6902 if Is_Enumeration_Type (P_Type)
6903 and then Expr_Value (E1) =
6904 Expr_Value (Type_Low_Bound (P_Base_Type))
6906 Apply_Compile_Time_Constraint_Error
6907 (N, "Pred of `&''First`",
6908 CE_Overflow_Check_Failed,
6910 Warn => not Static);
6916 Fold_Uint (N, Expr_Value (E1) - 1, Static);
6924 -- No processing required, because by this stage, Range has been
6925 -- replaced by First .. Last, so this branch can never be taken.
6927 when Attribute_Range =>
6928 raise Program_Error;
6934 when Attribute_Range_Length =>
6937 -- Can fold if both bounds are compile time known
6939 if Compile_Time_Known_Value (Hi_Bound)
6940 and then Compile_Time_Known_Value (Lo_Bound)
6944 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
6948 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6949 -- comparable, and we can figure out the difference between them.
6952 Diff : aliased Uint;
6956 Compile_Time_Compare
6957 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6960 Fold_Uint (N, Uint_1, False);
6963 Fold_Uint (N, Uint_0, False);
6966 if Diff /= No_Uint then
6967 Fold_Uint (N, Diff + 1, False);
6979 when Attribute_Ref =>
6980 Fold_Uint (N, Expr_Value (E1), True);
6986 when Attribute_Remainder => Remainder : declare
6987 X : constant Ureal := Expr_Value_R (E1);
6988 Y : constant Ureal := Expr_Value_R (E2);
6991 if UR_Is_Zero (Y) then
6992 Apply_Compile_Time_Constraint_Error
6993 (N, "division by zero in Remainder",
6994 CE_Overflow_Check_Failed,
6995 Warn => not Static);
7001 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
7008 when Attribute_Round => Round :
7014 -- First we get the (exact result) in units of small
7016 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
7018 -- Now round that exactly to an integer
7020 Si := UR_To_Uint (Sr);
7022 -- Finally the result is obtained by converting back to real
7024 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
7031 when Attribute_Rounding =>
7033 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
7039 when Attribute_Safe_Emax =>
7040 Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
7046 when Attribute_Safe_First =>
7047 Fold_Ureal (N, Safe_First_Value (P_Type), Static);
7053 when Attribute_Safe_Large =>
7054 if Is_Fixed_Point_Type (P_Type) then
7056 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
7058 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
7065 when Attribute_Safe_Last =>
7066 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
7072 when Attribute_Safe_Small =>
7074 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
7075 -- for fixed-point, since is the same as Small, but we implement
7076 -- it for backwards compatibility.
7078 if Is_Fixed_Point_Type (P_Type) then
7079 Fold_Ureal (N, Small_Value (P_Type), Static);
7081 -- Ada 83 Safe_Small for floating-point cases
7084 Fold_Ureal (N, Model_Small_Value (P_Type), Static);
7091 when Attribute_Scale =>
7092 Fold_Uint (N, Scale_Value (P_Type), True);
7098 when Attribute_Scaling =>
7101 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
7107 when Attribute_Signed_Zeros =>
7109 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
7115 -- Size attribute returns the RM size. All scalar types can be folded,
7116 -- as well as any types for which the size is known by the front end,
7117 -- including any type for which a size attribute is specified.
7119 when Attribute_Size | Attribute_VADS_Size => Size : declare
7120 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7123 if RM_Size (P_TypeA) /= Uint_0 then
7127 if Id = Attribute_VADS_Size or else Use_VADS_Size then
7129 S : constant Node_Id := Size_Clause (P_TypeA);
7132 -- If a size clause applies, then use the size from it.
7133 -- This is one of the rare cases where we can use the
7134 -- Size_Clause field for a subtype when Has_Size_Clause
7135 -- is False. Consider:
7137 -- type x is range 1 .. 64;
7138 -- for x'size use 12;
7139 -- subtype y is x range 0 .. 3;
7141 -- Here y has a size clause inherited from x, but normally
7142 -- it does not apply, and y'size is 2. However, y'VADS_Size
7143 -- is indeed 12 and not 2.
7146 and then Is_OK_Static_Expression (Expression (S))
7148 Fold_Uint (N, Expr_Value (Expression (S)), True);
7150 -- If no size is specified, then we simply use the object
7151 -- size in the VADS_Size case (e.g. Natural'Size is equal
7152 -- to Integer'Size, not one less).
7155 Fold_Uint (N, Esize (P_TypeA), True);
7159 -- Normal case (Size) in which case we want the RM_Size
7164 Static and then Is_Discrete_Type (P_TypeA));
7173 when Attribute_Small =>
7175 -- The floating-point case is present only for Ada 83 compatibility.
7176 -- Note that strictly this is an illegal addition, since we are
7177 -- extending an Ada 95 defined attribute, but we anticipate an
7178 -- ARG ruling that will permit this.
7180 if Is_Floating_Point_Type (P_Type) then
7182 -- Ada 83 attribute is defined as (RM83 3.5.8)
7184 -- T'Small = 2.0**(-T'Emax - 1)
7188 -- T'Emax = 4 * T'Mantissa
7190 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
7192 -- Normal Ada 95 fixed-point case
7195 Fold_Ureal (N, Small_Value (P_Type), True);
7202 when Attribute_Stream_Size =>
7209 when Attribute_Succ => Succ :
7211 -- Floating-point case
7213 if Is_Floating_Point_Type (P_Type) then
7215 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
7219 elsif Is_Fixed_Point_Type (P_Type) then
7221 Expr_Value_R (E1) + Small_Value (P_Type), Static);
7223 -- Modular integer case (wraps)
7225 elsif Is_Modular_Integer_Type (P_Type) then
7226 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
7228 -- Other scalar cases
7231 pragma Assert (Is_Scalar_Type (P_Type));
7233 if Is_Enumeration_Type (P_Type)
7234 and then Expr_Value (E1) =
7235 Expr_Value (Type_High_Bound (P_Base_Type))
7237 Apply_Compile_Time_Constraint_Error
7238 (N, "Succ of `&''Last`",
7239 CE_Overflow_Check_Failed,
7241 Warn => not Static);
7246 Fold_Uint (N, Expr_Value (E1) + 1, Static);
7255 when Attribute_Truncation =>
7257 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
7263 when Attribute_Type_Class => Type_Class : declare
7264 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
7268 if Is_Descendent_Of_Address (Typ) then
7269 Id := RE_Type_Class_Address;
7271 elsif Is_Enumeration_Type (Typ) then
7272 Id := RE_Type_Class_Enumeration;
7274 elsif Is_Integer_Type (Typ) then
7275 Id := RE_Type_Class_Integer;
7277 elsif Is_Fixed_Point_Type (Typ) then
7278 Id := RE_Type_Class_Fixed_Point;
7280 elsif Is_Floating_Point_Type (Typ) then
7281 Id := RE_Type_Class_Floating_Point;
7283 elsif Is_Array_Type (Typ) then
7284 Id := RE_Type_Class_Array;
7286 elsif Is_Record_Type (Typ) then
7287 Id := RE_Type_Class_Record;
7289 elsif Is_Access_Type (Typ) then
7290 Id := RE_Type_Class_Access;
7292 elsif Is_Enumeration_Type (Typ) then
7293 Id := RE_Type_Class_Enumeration;
7295 elsif Is_Task_Type (Typ) then
7296 Id := RE_Type_Class_Task;
7298 -- We treat protected types like task types. It would make more
7299 -- sense to have another enumeration value, but after all the
7300 -- whole point of this feature is to be exactly DEC compatible,
7301 -- and changing the type Type_Class would not meet this requirement.
7303 elsif Is_Protected_Type (Typ) then
7304 Id := RE_Type_Class_Task;
7306 -- Not clear if there are any other possibilities, but if there
7307 -- are, then we will treat them as the address case.
7310 Id := RE_Type_Class_Address;
7313 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
7316 -----------------------
7317 -- Unbiased_Rounding --
7318 -----------------------
7320 when Attribute_Unbiased_Rounding =>
7322 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7325 -------------------------
7326 -- Unconstrained_Array --
7327 -------------------------
7329 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7330 Typ : constant Entity_Id := Underlying_Type (P_Type);
7333 Rewrite (N, New_Occurrence_Of (
7335 Is_Array_Type (P_Type)
7336 and then not Is_Constrained (Typ)), Loc));
7338 -- Analyze and resolve as boolean, note that this attribute is
7339 -- a static attribute in GNAT.
7341 Analyze_And_Resolve (N, Standard_Boolean);
7343 end Unconstrained_Array;
7349 -- Processing is shared with Size
7355 when Attribute_Val => Val :
7357 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7359 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7361 Apply_Compile_Time_Constraint_Error
7362 (N, "Val expression out of range",
7363 CE_Range_Check_Failed,
7364 Warn => not Static);
7370 Fold_Uint (N, Expr_Value (E1), Static);
7378 -- The Value_Size attribute for a type returns the RM size of the
7379 -- type. This an always be folded for scalar types, and can also
7380 -- be folded for non-scalar types if the size is set.
7382 when Attribute_Value_Size => Value_Size : declare
7383 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7385 if RM_Size (P_TypeA) /= Uint_0 then
7386 Fold_Uint (N, RM_Size (P_TypeA), True);
7394 -- Version can never be static
7396 when Attribute_Version =>
7403 -- Wide_Image is a scalar attribute, but is never static, because it
7404 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7406 when Attribute_Wide_Image =>
7409 ---------------------
7410 -- Wide_Wide_Image --
7411 ---------------------
7413 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7414 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7416 when Attribute_Wide_Wide_Image =>
7419 ---------------------
7420 -- Wide_Wide_Width --
7421 ---------------------
7423 -- Processing for Wide_Wide_Width is combined with Width
7429 -- Processing for Wide_Width is combined with Width
7435 -- This processing also handles the case of Wide_[Wide_]Width
7437 when Attribute_Width |
7438 Attribute_Wide_Width |
7439 Attribute_Wide_Wide_Width => Width :
7441 if Compile_Time_Known_Bounds (P_Type) then
7443 -- Floating-point types
7445 if Is_Floating_Point_Type (P_Type) then
7447 -- Width is zero for a null range (RM 3.5 (38))
7449 if Expr_Value_R (Type_High_Bound (P_Type)) <
7450 Expr_Value_R (Type_Low_Bound (P_Type))
7452 Fold_Uint (N, Uint_0, True);
7455 -- For floating-point, we have +N.dddE+nnn where length
7456 -- of ddd is determined by type'Digits - 1, but is one
7457 -- if Digits is one (RM 3.5 (33)).
7459 -- nnn is set to 2 for Short_Float and Float (32 bit
7460 -- floats), and 3 for Long_Float and Long_Long_Float.
7461 -- For machines where Long_Long_Float is the IEEE
7462 -- extended precision type, the exponent takes 4 digits.
7466 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7469 if Esize (P_Type) <= 32 then
7471 elsif Esize (P_Type) = 64 then
7477 Fold_Uint (N, UI_From_Int (Len), True);
7481 -- Fixed-point types
7483 elsif Is_Fixed_Point_Type (P_Type) then
7485 -- Width is zero for a null range (RM 3.5 (38))
7487 if Expr_Value (Type_High_Bound (P_Type)) <
7488 Expr_Value (Type_Low_Bound (P_Type))
7490 Fold_Uint (N, Uint_0, True);
7492 -- The non-null case depends on the specific real type
7495 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7498 (N, UI_From_Int (Fore_Value + 1) + Aft_Value (P_Type),
7506 R : constant Entity_Id := Root_Type (P_Type);
7507 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7508 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7521 -- Width for types derived from Standard.Character
7522 -- and Standard.Wide_[Wide_]Character.
7524 elsif Is_Standard_Character_Type (P_Type) then
7527 -- Set W larger if needed
7529 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7531 -- All wide characters look like Hex_hhhhhhhh
7535 -- No need to compute this more than once!
7540 C := Character'Val (J);
7542 -- Test for all cases where Character'Image
7543 -- yields an image that is longer than three
7544 -- characters. First the cases of Reserved_xxx
7545 -- names (length = 12).
7548 when Reserved_128 | Reserved_129 |
7549 Reserved_132 | Reserved_153
7552 when BS | HT | LF | VT | FF | CR |
7553 SO | SI | EM | FS | GS | RS |
7554 US | RI | MW | ST | PM
7557 when NUL | SOH | STX | ETX | EOT |
7558 ENQ | ACK | BEL | DLE | DC1 |
7559 DC2 | DC3 | DC4 | NAK | SYN |
7560 ETB | CAN | SUB | ESC | DEL |
7561 BPH | NBH | NEL | SSA | ESA |
7562 HTS | HTJ | VTS | PLD | PLU |
7563 SS2 | SS3 | DCS | PU1 | PU2 |
7564 STS | CCH | SPA | EPA | SOS |
7565 SCI | CSI | OSC | APC
7568 when Space .. Tilde |
7569 No_Break_Space .. LC_Y_Diaeresis
7571 -- Special case of soft hyphen in Ada 2005
7573 if C = Character'Val (16#AD#)
7574 and then Ada_Version >= Ada_2005
7582 W := Int'Max (W, Wt);
7586 -- Width for types derived from Standard.Boolean
7588 elsif R = Standard_Boolean then
7595 -- Width for integer types
7597 elsif Is_Integer_Type (P_Type) then
7598 T := UI_Max (abs Lo, abs Hi);
7606 -- Only remaining possibility is user declared enum type
7609 pragma Assert (Is_Enumeration_Type (P_Type));
7612 L := First_Literal (P_Type);
7614 while Present (L) loop
7616 -- Only pay attention to in range characters
7618 if Lo <= Enumeration_Pos (L)
7619 and then Enumeration_Pos (L) <= Hi
7621 -- For Width case, use decoded name
7623 if Id = Attribute_Width then
7624 Get_Decoded_Name_String (Chars (L));
7625 Wt := Nat (Name_Len);
7627 -- For Wide_[Wide_]Width, use encoded name, and
7628 -- then adjust for the encoding.
7631 Get_Name_String (Chars (L));
7633 -- Character literals are always of length 3
7635 if Name_Buffer (1) = 'Q' then
7638 -- Otherwise loop to adjust for upper/wide chars
7641 Wt := Nat (Name_Len);
7643 for J in 1 .. Name_Len loop
7644 if Name_Buffer (J) = 'U' then
7646 elsif Name_Buffer (J) = 'W' then
7653 W := Int'Max (W, Wt);
7660 Fold_Uint (N, UI_From_Int (W), True);
7666 -- The following attributes denote functions that cannot be folded
7668 when Attribute_From_Any |
7670 Attribute_TypeCode =>
7673 -- The following attributes can never be folded, and furthermore we
7674 -- should not even have entered the case statement for any of these.
7675 -- Note that in some cases, the values have already been folded as
7676 -- a result of the processing in Analyze_Attribute.
7678 when Attribute_Abort_Signal |
7681 Attribute_Address_Size |
7682 Attribute_Asm_Input |
7683 Attribute_Asm_Output |
7685 Attribute_Bit_Order |
7686 Attribute_Bit_Position |
7687 Attribute_Callable |
7690 Attribute_Code_Address |
7691 Attribute_Compiler_Version |
7693 Attribute_Default_Bit_Order |
7694 Attribute_Elaborated |
7695 Attribute_Elab_Body |
7696 Attribute_Elab_Spec |
7698 Attribute_External_Tag |
7699 Attribute_Fast_Math |
7700 Attribute_First_Bit |
7702 Attribute_Last_Bit |
7703 Attribute_Maximum_Alignment |
7706 Attribute_Partition_ID |
7707 Attribute_Pool_Address |
7708 Attribute_Position |
7709 Attribute_Priority |
7712 Attribute_Storage_Pool |
7713 Attribute_Storage_Size |
7714 Attribute_Storage_Unit |
7715 Attribute_Stub_Type |
7717 Attribute_Target_Name |
7718 Attribute_Terminated |
7719 Attribute_To_Address |
7720 Attribute_Type_Key |
7721 Attribute_UET_Address |
7722 Attribute_Unchecked_Access |
7723 Attribute_Universal_Literal_String |
7724 Attribute_Unrestricted_Access |
7727 Attribute_Wchar_T_Size |
7728 Attribute_Wide_Value |
7729 Attribute_Wide_Wide_Value |
7730 Attribute_Word_Size |
7733 raise Program_Error;
7736 -- At the end of the case, one more check. If we did a static evaluation
7737 -- so that the result is now a literal, then set Is_Static_Expression
7738 -- in the constant only if the prefix type is a static subtype. For
7739 -- non-static subtypes, the folding is still OK, but not static.
7741 -- An exception is the GNAT attribute Constrained_Array which is
7742 -- defined to be a static attribute in all cases.
7744 if Nkind_In (N, N_Integer_Literal,
7746 N_Character_Literal,
7748 or else (Is_Entity_Name (N)
7749 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7751 Set_Is_Static_Expression (N, Static);
7753 -- If this is still an attribute reference, then it has not been folded
7754 -- and that means that its expressions are in a non-static context.
7756 elsif Nkind (N) = N_Attribute_Reference then
7759 -- Note: the else case not covered here are odd cases where the
7760 -- processing has transformed the attribute into something other
7761 -- than a constant. Nothing more to do in such cases.
7768 ------------------------------
7769 -- Is_Anonymous_Tagged_Base --
7770 ------------------------------
7772 function Is_Anonymous_Tagged_Base
7779 Anon = Current_Scope
7780 and then Is_Itype (Anon)
7781 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
7782 end Is_Anonymous_Tagged_Base;
7784 --------------------------------
7785 -- Name_Implies_Lvalue_Prefix --
7786 --------------------------------
7788 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
7789 pragma Assert (Is_Attribute_Name (Nam));
7791 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
7792 end Name_Implies_Lvalue_Prefix;
7794 -----------------------
7795 -- Resolve_Attribute --
7796 -----------------------
7798 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
7799 Loc : constant Source_Ptr := Sloc (N);
7800 P : constant Node_Id := Prefix (N);
7801 Aname : constant Name_Id := Attribute_Name (N);
7802 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7803 Btyp : constant Entity_Id := Base_Type (Typ);
7804 Des_Btyp : Entity_Id;
7805 Index : Interp_Index;
7807 Nom_Subt : Entity_Id;
7809 procedure Accessibility_Message;
7810 -- Error, or warning within an instance, if the static accessibility
7811 -- rules of 3.10.2 are violated.
7813 ---------------------------
7814 -- Accessibility_Message --
7815 ---------------------------
7817 procedure Accessibility_Message is
7818 Indic : Node_Id := Parent (Parent (N));
7821 -- In an instance, this is a runtime check, but one we
7822 -- know will fail, so generate an appropriate warning.
7824 if In_Instance_Body then
7825 Error_Msg_F ("?non-local pointer cannot point to local object", P);
7827 ("\?Program_Error will be raised at run time", P);
7829 Make_Raise_Program_Error (Loc,
7830 Reason => PE_Accessibility_Check_Failed));
7835 Error_Msg_F ("non-local pointer cannot point to local object", P);
7837 -- Check for case where we have a missing access definition
7839 if Is_Record_Type (Current_Scope)
7841 Nkind_In (Parent (N), N_Discriminant_Association,
7842 N_Index_Or_Discriminant_Constraint)
7844 Indic := Parent (Parent (N));
7845 while Present (Indic)
7846 and then Nkind (Indic) /= N_Subtype_Indication
7848 Indic := Parent (Indic);
7851 if Present (Indic) then
7853 ("\use an access definition for" &
7854 " the access discriminant of&",
7855 N, Entity (Subtype_Mark (Indic)));
7859 end Accessibility_Message;
7861 -- Start of processing for Resolve_Attribute
7864 -- If error during analysis, no point in continuing, except for array
7865 -- types, where we get better recovery by using unconstrained indexes
7866 -- than nothing at all (see Check_Array_Type).
7869 and then Attr_Id /= Attribute_First
7870 and then Attr_Id /= Attribute_Last
7871 and then Attr_Id /= Attribute_Length
7872 and then Attr_Id /= Attribute_Range
7877 -- If attribute was universal type, reset to actual type
7879 if Etype (N) = Universal_Integer
7880 or else Etype (N) = Universal_Real
7885 -- Remaining processing depends on attribute
7893 -- For access attributes, if the prefix denotes an entity, it is
7894 -- interpreted as a name, never as a call. It may be overloaded,
7895 -- in which case resolution uses the profile of the context type.
7896 -- Otherwise prefix must be resolved.
7898 when Attribute_Access
7899 | Attribute_Unchecked_Access
7900 | Attribute_Unrestricted_Access =>
7904 if Is_Variable (P) then
7905 Note_Possible_Modification (P, Sure => False);
7908 -- The following comes from a query by Adam Beneschan, concerning
7909 -- improper use of universal_access in equality tests involving
7910 -- anonymous access types. Another good reason for 'Ref, but
7911 -- for now disable the test, which breaks several filed tests.
7913 if Ekind (Typ) = E_Anonymous_Access_Type
7914 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
7917 Error_Msg_N ("need unique type to resolve 'Access", N);
7918 Error_Msg_N ("\qualify attribute with some access type", N);
7921 if Is_Entity_Name (P) then
7922 if Is_Overloaded (P) then
7923 Get_First_Interp (P, Index, It);
7924 while Present (It.Nam) loop
7925 if Type_Conformant (Designated_Type (Typ), It.Nam) then
7926 Set_Entity (P, It.Nam);
7928 -- The prefix is definitely NOT overloaded anymore at
7929 -- this point, so we reset the Is_Overloaded flag to
7930 -- avoid any confusion when reanalyzing the node.
7932 Set_Is_Overloaded (P, False);
7933 Set_Is_Overloaded (N, False);
7934 Generate_Reference (Entity (P), P);
7938 Get_Next_Interp (Index, It);
7941 -- If Prefix is a subprogram name, it is frozen by this
7944 -- If it is a type, there is nothing to resolve.
7945 -- If it is an object, complete its resolution.
7947 elsif Is_Overloadable (Entity (P)) then
7949 -- Avoid insertion of freeze actions in spec expression mode
7951 if not In_Spec_Expression then
7952 Freeze_Before (N, Entity (P));
7955 elsif Is_Type (Entity (P)) then
7961 Error_Msg_Name_1 := Aname;
7963 if not Is_Entity_Name (P) then
7966 elsif Is_Overloadable (Entity (P))
7967 and then Is_Abstract_Subprogram (Entity (P))
7969 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
7970 Set_Etype (N, Any_Type);
7972 elsif Convention (Entity (P)) = Convention_Intrinsic then
7973 if Ekind (Entity (P)) = E_Enumeration_Literal then
7975 ("prefix of % attribute cannot be enumeration literal",
7979 ("prefix of % attribute cannot be intrinsic", P);
7982 Set_Etype (N, Any_Type);
7985 -- Assignments, return statements, components of aggregates,
7986 -- generic instantiations will require convention checks if
7987 -- the type is an access to subprogram. Given that there will
7988 -- also be accessibility checks on those, this is where the
7989 -- checks can eventually be centralized ???
7991 if Ekind_In (Btyp, E_Access_Subprogram_Type,
7992 E_Anonymous_Access_Subprogram_Type,
7993 E_Access_Protected_Subprogram_Type,
7994 E_Anonymous_Access_Protected_Subprogram_Type)
7996 -- Deal with convention mismatch
7998 if Convention (Designated_Type (Btyp)) /=
7999 Convention (Entity (P))
8002 ("subprogram & has wrong convention", P, Entity (P));
8004 ("\does not match convention of access type &",
8007 if not Has_Convention_Pragma (Btyp) then
8009 ("\probable missing pragma Convention for &",
8014 Check_Subtype_Conformant
8015 (New_Id => Entity (P),
8016 Old_Id => Designated_Type (Btyp),
8020 if Attr_Id = Attribute_Unchecked_Access then
8021 Error_Msg_Name_1 := Aname;
8023 ("attribute% cannot be applied to a subprogram", P);
8025 elsif Aname = Name_Unrestricted_Access then
8026 null; -- Nothing to check
8028 -- Check the static accessibility rule of 3.10.2(32).
8029 -- This rule also applies within the private part of an
8030 -- instantiation. This rule does not apply to anonymous
8031 -- access-to-subprogram types in access parameters.
8033 elsif Attr_Id = Attribute_Access
8034 and then not In_Instance_Body
8036 (Ekind (Btyp) = E_Access_Subprogram_Type
8037 or else Is_Local_Anonymous_Access (Btyp))
8039 and then Subprogram_Access_Level (Entity (P)) >
8040 Type_Access_Level (Btyp)
8043 ("subprogram must not be deeper than access type", P);
8045 -- Check the restriction of 3.10.2(32) that disallows the
8046 -- access attribute within a generic body when the ultimate
8047 -- ancestor of the type of the attribute is declared outside
8048 -- of the generic unit and the subprogram is declared within
8049 -- that generic unit. This includes any such attribute that
8050 -- occurs within the body of a generic unit that is a child
8051 -- of the generic unit where the subprogram is declared.
8053 -- The rule also prohibits applying the attribute when the
8054 -- access type is a generic formal access type (since the
8055 -- level of the actual type is not known). This restriction
8056 -- does not apply when the attribute type is an anonymous
8057 -- access-to-subprogram type. Note that this check was
8058 -- revised by AI-229, because the originally Ada 95 rule
8059 -- was too lax. The original rule only applied when the
8060 -- subprogram was declared within the body of the generic,
8061 -- which allowed the possibility of dangling references).
8062 -- The rule was also too strict in some case, in that it
8063 -- didn't permit the access to be declared in the generic
8064 -- spec, whereas the revised rule does (as long as it's not
8067 -- There are a couple of subtleties of the test for applying
8068 -- the check that are worth noting. First, we only apply it
8069 -- when the levels of the subprogram and access type are the
8070 -- same (the case where the subprogram is statically deeper
8071 -- was applied above, and the case where the type is deeper
8072 -- is always safe). Second, we want the check to apply
8073 -- within nested generic bodies and generic child unit
8074 -- bodies, but not to apply to an attribute that appears in
8075 -- the generic unit's specification. This is done by testing
8076 -- that the attribute's innermost enclosing generic body is
8077 -- not the same as the innermost generic body enclosing the
8078 -- generic unit where the subprogram is declared (we don't
8079 -- want the check to apply when the access attribute is in
8080 -- the spec and there's some other generic body enclosing
8081 -- generic). Finally, there's no point applying the check
8082 -- when within an instance, because any violations will have
8083 -- been caught by the compilation of the generic unit.
8085 -- Note that we relax this check in CodePeer mode for
8086 -- compatibility with legacy code, since CodePeer is an
8087 -- Ada source code analyzer, not a strict compiler.
8088 -- ??? Note that a better approach would be to have a
8089 -- separate switch to relax this rule, and enable this
8090 -- switch in CodePeer mode.
8092 elsif Attr_Id = Attribute_Access
8093 and then not CodePeer_Mode
8094 and then not In_Instance
8095 and then Present (Enclosing_Generic_Unit (Entity (P)))
8096 and then Present (Enclosing_Generic_Body (N))
8097 and then Enclosing_Generic_Body (N) /=
8098 Enclosing_Generic_Body
8099 (Enclosing_Generic_Unit (Entity (P)))
8100 and then Subprogram_Access_Level (Entity (P)) =
8101 Type_Access_Level (Btyp)
8102 and then Ekind (Btyp) /=
8103 E_Anonymous_Access_Subprogram_Type
8104 and then Ekind (Btyp) /=
8105 E_Anonymous_Access_Protected_Subprogram_Type
8107 -- The attribute type's ultimate ancestor must be
8108 -- declared within the same generic unit as the
8109 -- subprogram is declared. The error message is
8110 -- specialized to say "ancestor" for the case where the
8111 -- access type is not its own ancestor, since saying
8112 -- simply "access type" would be very confusing.
8114 if Enclosing_Generic_Unit (Entity (P)) /=
8115 Enclosing_Generic_Unit (Root_Type (Btyp))
8118 ("''Access attribute not allowed in generic body",
8121 if Root_Type (Btyp) = Btyp then
8124 "access type & is declared outside " &
8125 "generic unit (RM 3.10.2(32))", N, Btyp);
8128 ("\because ancestor of " &
8129 "access type & is declared outside " &
8130 "generic unit (RM 3.10.2(32))", N, Btyp);
8134 ("\move ''Access to private part, or " &
8135 "(Ada 2005) use anonymous access type instead of &",
8138 -- If the ultimate ancestor of the attribute's type is
8139 -- a formal type, then the attribute is illegal because
8140 -- the actual type might be declared at a higher level.
8141 -- The error message is specialized to say "ancestor"
8142 -- for the case where the access type is not its own
8143 -- ancestor, since saying simply "access type" would be
8146 elsif Is_Generic_Type (Root_Type (Btyp)) then
8147 if Root_Type (Btyp) = Btyp then
8149 ("access type must not be a generic formal type",
8153 ("ancestor access type must not be a generic " &
8160 -- If this is a renaming, an inherited operation, or a
8161 -- subprogram instance, use the original entity. This may make
8162 -- the node type-inconsistent, so this transformation can only
8163 -- be done if the node will not be reanalyzed. In particular,
8164 -- if it is within a default expression, the transformation
8165 -- must be delayed until the default subprogram is created for
8166 -- it, when the enclosing subprogram is frozen.
8168 if Is_Entity_Name (P)
8169 and then Is_Overloadable (Entity (P))
8170 and then Present (Alias (Entity (P)))
8171 and then Expander_Active
8174 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8177 elsif Nkind (P) = N_Selected_Component
8178 and then Is_Overloadable (Entity (Selector_Name (P)))
8180 -- Protected operation. If operation is overloaded, must
8181 -- disambiguate. Prefix that denotes protected object itself
8182 -- is resolved with its own type.
8184 if Attr_Id = Attribute_Unchecked_Access then
8185 Error_Msg_Name_1 := Aname;
8187 ("attribute% cannot be applied to protected operation", P);
8190 Resolve (Prefix (P));
8191 Generate_Reference (Entity (Selector_Name (P)), P);
8193 elsif Is_Overloaded (P) then
8195 -- Use the designated type of the context to disambiguate
8196 -- Note that this was not strictly conformant to Ada 95,
8197 -- but was the implementation adopted by most Ada 95 compilers.
8198 -- The use of the context type to resolve an Access attribute
8199 -- reference is now mandated in AI-235 for Ada 2005.
8202 Index : Interp_Index;
8206 Get_First_Interp (P, Index, It);
8207 while Present (It.Typ) loop
8208 if Covers (Designated_Type (Typ), It.Typ) then
8209 Resolve (P, It.Typ);
8213 Get_Next_Interp (Index, It);
8220 -- X'Access is illegal if X denotes a constant and the access type
8221 -- is access-to-variable. Same for 'Unchecked_Access. The rule
8222 -- does not apply to 'Unrestricted_Access. If the reference is a
8223 -- default-initialized aggregate component for a self-referential
8224 -- type the reference is legal.
8226 if not (Ekind (Btyp) = E_Access_Subprogram_Type
8227 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
8228 or else (Is_Record_Type (Btyp)
8230 Present (Corresponding_Remote_Type (Btyp)))
8231 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8232 or else Ekind (Btyp)
8233 = E_Anonymous_Access_Protected_Subprogram_Type
8234 or else Is_Access_Constant (Btyp)
8235 or else Is_Variable (P)
8236 or else Attr_Id = Attribute_Unrestricted_Access)
8238 if Is_Entity_Name (P)
8239 and then Is_Type (Entity (P))
8241 -- Legality of a self-reference through an access
8242 -- attribute has been verified in Analyze_Access_Attribute.
8246 elsif Comes_From_Source (N) then
8247 Error_Msg_F ("access-to-variable designates constant", P);
8251 Des_Btyp := Designated_Type (Btyp);
8253 if Ada_Version >= Ada_2005
8254 and then Is_Incomplete_Type (Des_Btyp)
8256 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
8257 -- imported entity, and the non-limited view is visible, make
8258 -- use of it. If it is an incomplete subtype, use the base type
8261 if From_With_Type (Des_Btyp)
8262 and then Present (Non_Limited_View (Des_Btyp))
8264 Des_Btyp := Non_Limited_View (Des_Btyp);
8266 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
8267 Des_Btyp := Etype (Des_Btyp);
8271 if (Attr_Id = Attribute_Access
8273 Attr_Id = Attribute_Unchecked_Access)
8274 and then (Ekind (Btyp) = E_General_Access_Type
8275 or else Ekind (Btyp) = E_Anonymous_Access_Type)
8277 -- Ada 2005 (AI-230): Check the accessibility of anonymous
8278 -- access types for stand-alone objects, record and array
8279 -- components, and return objects. For a component definition
8280 -- the level is the same of the enclosing composite type.
8282 if Ada_Version >= Ada_2005
8283 and then Is_Local_Anonymous_Access (Btyp)
8284 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8285 and then Attr_Id = Attribute_Access
8287 -- In an instance, this is a runtime check, but one we
8288 -- know will fail, so generate an appropriate warning.
8290 if In_Instance_Body then
8292 ("?non-local pointer cannot point to local object", P);
8294 ("\?Program_Error will be raised at run time", P);
8296 Make_Raise_Program_Error (Loc,
8297 Reason => PE_Accessibility_Check_Failed));
8302 ("non-local pointer cannot point to local object", P);
8306 if Is_Dependent_Component_Of_Mutable_Object (P) then
8308 ("illegal attribute for discriminant-dependent component",
8312 -- Check static matching rule of 3.10.2(27). Nominal subtype
8313 -- of the prefix must statically match the designated type.
8315 Nom_Subt := Etype (P);
8317 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
8318 Nom_Subt := Base_Type (Nom_Subt);
8321 if Is_Tagged_Type (Designated_Type (Typ)) then
8323 -- If the attribute is in the context of an access
8324 -- parameter, then the prefix is allowed to be of the
8325 -- class-wide type (by AI-127).
8327 if Ekind (Typ) = E_Anonymous_Access_Type then
8328 if not Covers (Designated_Type (Typ), Nom_Subt)
8329 and then not Covers (Nom_Subt, Designated_Type (Typ))
8335 Desig := Designated_Type (Typ);
8337 if Is_Class_Wide_Type (Desig) then
8338 Desig := Etype (Desig);
8341 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8346 ("type of prefix: & not compatible",
8349 ("\with &, the expected designated type",
8350 P, Designated_Type (Typ));
8355 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8357 (not Is_Class_Wide_Type (Designated_Type (Typ))
8358 and then Is_Class_Wide_Type (Nom_Subt))
8361 ("type of prefix: & is not covered", P, Nom_Subt);
8363 ("\by &, the expected designated type" &
8364 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8367 if Is_Class_Wide_Type (Designated_Type (Typ))
8368 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8369 and then Is_Constrained (Etype (Designated_Type (Typ)))
8370 and then Designated_Type (Typ) /= Nom_Subt
8372 Apply_Discriminant_Check
8373 (N, Etype (Designated_Type (Typ)));
8376 -- Ada 2005 (AI-363): Require static matching when designated
8377 -- type has discriminants and a constrained partial view, since
8378 -- in general objects of such types are mutable, so we can't
8379 -- allow the access value to designate a constrained object
8380 -- (because access values must be assumed to designate mutable
8381 -- objects when designated type does not impose a constraint).
8383 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8386 elsif Has_Discriminants (Designated_Type (Typ))
8387 and then not Is_Constrained (Des_Btyp)
8389 (Ada_Version < Ada_2005
8391 not Has_Constrained_Partial_View
8392 (Designated_Type (Base_Type (Typ))))
8398 ("object subtype must statically match "
8399 & "designated subtype", P);
8401 if Is_Entity_Name (P)
8402 and then Is_Array_Type (Designated_Type (Typ))
8405 D : constant Node_Id := Declaration_Node (Entity (P));
8408 Error_Msg_N ("aliased object has explicit bounds?",
8410 Error_Msg_N ("\declare without bounds"
8411 & " (and with explicit initialization)?", D);
8412 Error_Msg_N ("\for use with unconstrained access?", D);
8417 -- Check the static accessibility rule of 3.10.2(28).
8418 -- Note that this check is not performed for the
8419 -- case of an anonymous access type, since the access
8420 -- attribute is always legal in such a context.
8422 if Attr_Id /= Attribute_Unchecked_Access
8423 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8424 and then Ekind (Btyp) = E_General_Access_Type
8426 Accessibility_Message;
8431 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
8432 E_Anonymous_Access_Protected_Subprogram_Type)
8434 if Is_Entity_Name (P)
8435 and then not Is_Protected_Type (Scope (Entity (P)))
8437 Error_Msg_F ("context requires a protected subprogram", P);
8439 -- Check accessibility of protected object against that of the
8440 -- access type, but only on user code, because the expander
8441 -- creates access references for handlers. If the context is an
8442 -- anonymous_access_to_protected, there are no accessibility
8443 -- checks either. Omit check entirely for Unrestricted_Access.
8445 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8446 and then Comes_From_Source (N)
8447 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8448 and then Attr_Id /= Attribute_Unrestricted_Access
8450 Accessibility_Message;
8454 elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
8455 E_Anonymous_Access_Subprogram_Type)
8456 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8458 Error_Msg_F ("context requires a non-protected subprogram", P);
8461 -- The context cannot be a pool-specific type, but this is a
8462 -- legality rule, not a resolution rule, so it must be checked
8463 -- separately, after possibly disambiguation (see AI-245).
8465 if Ekind (Btyp) = E_Access_Type
8466 and then Attr_Id /= Attribute_Unrestricted_Access
8468 Wrong_Type (N, Typ);
8471 -- The context may be a constrained access type (however ill-
8472 -- advised such subtypes might be) so in order to generate a
8473 -- constraint check when needed set the type of the attribute
8474 -- reference to the base type of the context.
8476 Set_Etype (N, Btyp);
8478 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8480 if Attr_Id /= Attribute_Unrestricted_Access then
8481 if Is_Atomic_Object (P)
8482 and then not Is_Atomic (Designated_Type (Typ))
8485 ("access to atomic object cannot yield access-to-" &
8486 "non-atomic type", P);
8488 elsif Is_Volatile_Object (P)
8489 and then not Is_Volatile (Designated_Type (Typ))
8492 ("access to volatile object cannot yield access-to-" &
8493 "non-volatile type", P);
8497 if Is_Entity_Name (P) then
8498 Set_Address_Taken (Entity (P));
8500 end Access_Attribute;
8506 -- Deal with resolving the type for Address attribute, overloading
8507 -- is not permitted here, since there is no context to resolve it.
8509 when Attribute_Address | Attribute_Code_Address =>
8510 Address_Attribute : begin
8512 -- To be safe, assume that if the address of a variable is taken,
8513 -- it may be modified via this address, so note modification.
8515 if Is_Variable (P) then
8516 Note_Possible_Modification (P, Sure => False);
8519 if Nkind (P) in N_Subexpr
8520 and then Is_Overloaded (P)
8522 Get_First_Interp (P, Index, It);
8523 Get_Next_Interp (Index, It);
8525 if Present (It.Nam) then
8526 Error_Msg_Name_1 := Aname;
8528 ("prefix of % attribute cannot be overloaded", P);
8532 if not Is_Entity_Name (P)
8533 or else not Is_Overloadable (Entity (P))
8535 if not Is_Task_Type (Etype (P))
8536 or else Nkind (P) = N_Explicit_Dereference
8542 -- If this is the name of a derived subprogram, or that of a
8543 -- generic actual, the address is that of the original entity.
8545 if Is_Entity_Name (P)
8546 and then Is_Overloadable (Entity (P))
8547 and then Present (Alias (Entity (P)))
8550 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8553 if Is_Entity_Name (P) then
8554 Set_Address_Taken (Entity (P));
8557 if Nkind (P) = N_Slice then
8559 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8560 -- even if the array is packed and the slice itself is not
8561 -- addressable. Transform the prefix into an indexed component.
8563 -- Note that the transformation is safe only if we know that
8564 -- the slice is non-null. That is because a null slice can have
8565 -- an out of bounds index value.
8567 -- Right now, gigi blows up if given 'Address on a slice as a
8568 -- result of some incorrect freeze nodes generated by the front
8569 -- end, and this covers up that bug in one case, but the bug is
8570 -- likely still there in the cases not handled by this code ???
8572 -- It's not clear what 'Address *should* return for a null
8573 -- slice with out of bounds indexes, this might be worth an ARG
8576 -- One approach would be to do a length check unconditionally,
8577 -- and then do the transformation below unconditionally, but
8578 -- analyze with checks off, avoiding the problem of the out of
8579 -- bounds index. This approach would interpret the address of
8580 -- an out of bounds null slice as being the address where the
8581 -- array element would be if there was one, which is probably
8582 -- as reasonable an interpretation as any ???
8585 Loc : constant Source_Ptr := Sloc (P);
8586 D : constant Node_Id := Discrete_Range (P);
8590 if Is_Entity_Name (D)
8593 (Type_Low_Bound (Entity (D)),
8594 Type_High_Bound (Entity (D)))
8597 Make_Attribute_Reference (Loc,
8598 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8599 Attribute_Name => Name_First);
8601 elsif Nkind (D) = N_Range
8602 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8604 Lo := Low_Bound (D);
8610 if Present (Lo) then
8612 Make_Indexed_Component (Loc,
8613 Prefix => Relocate_Node (Prefix (P)),
8614 Expressions => New_List (Lo)));
8616 Analyze_And_Resolve (P);
8620 end Address_Attribute;
8626 -- Prefix of the AST_Entry attribute is an entry name which must
8627 -- not be resolved, since this is definitely not an entry call.
8629 when Attribute_AST_Entry =>
8636 -- Prefix of Body_Version attribute can be a subprogram name which
8637 -- must not be resolved, since this is not a call.
8639 when Attribute_Body_Version =>
8646 -- Prefix of Caller attribute is an entry name which must not
8647 -- be resolved, since this is definitely not an entry call.
8649 when Attribute_Caller =>
8656 -- Shares processing with Address attribute
8662 -- If the prefix of the Count attribute is an entry name it must not
8663 -- be resolved, since this is definitely not an entry call. However,
8664 -- if it is an element of an entry family, the index itself may
8665 -- have to be resolved because it can be a general expression.
8667 when Attribute_Count =>
8668 if Nkind (P) = N_Indexed_Component
8669 and then Is_Entity_Name (Prefix (P))
8672 Indx : constant Node_Id := First (Expressions (P));
8673 Fam : constant Entity_Id := Entity (Prefix (P));
8675 Resolve (Indx, Entry_Index_Type (Fam));
8676 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8684 -- Prefix of the Elaborated attribute is a subprogram name which
8685 -- must not be resolved, since this is definitely not a call. Note
8686 -- that it is a library unit, so it cannot be overloaded here.
8688 when Attribute_Elaborated =>
8695 -- Prefix of Enabled attribute is a check name, which must be treated
8696 -- specially and not touched by Resolve.
8698 when Attribute_Enabled =>
8701 --------------------
8702 -- Mechanism_Code --
8703 --------------------
8705 -- Prefix of the Mechanism_Code attribute is a function name
8706 -- which must not be resolved. Should we check for overloaded ???
8708 when Attribute_Mechanism_Code =>
8715 -- Most processing is done in sem_dist, after determining the
8716 -- context type. Node is rewritten as a conversion to a runtime call.
8718 when Attribute_Partition_ID =>
8719 Process_Partition_Id (N);
8726 when Attribute_Pool_Address =>
8733 -- We replace the Range attribute node with a range expression whose
8734 -- bounds are the 'First and 'Last attributes applied to the same
8735 -- prefix. The reason that we do this transformation here instead of
8736 -- in the expander is that it simplifies other parts of the semantic
8737 -- analysis which assume that the Range has been replaced; thus it
8738 -- must be done even when in semantic-only mode (note that the RM
8739 -- specifically mentions this equivalence, we take care that the
8740 -- prefix is only evaluated once).
8742 when Attribute_Range => Range_Attribute :
8748 if not Is_Entity_Name (P)
8749 or else not Is_Type (Entity (P))
8755 Make_Attribute_Reference (Loc,
8757 Duplicate_Subexpr (P, Name_Req => True),
8758 Attribute_Name => Name_Last,
8759 Expressions => Expressions (N));
8762 Make_Attribute_Reference (Loc,
8764 Attribute_Name => Name_First,
8765 Expressions => Expressions (N));
8767 -- If the original was marked as Must_Not_Freeze (see code
8768 -- in Sem_Ch3.Make_Index), then make sure the rewriting
8769 -- does not freeze either.
8771 if Must_Not_Freeze (N) then
8772 Set_Must_Not_Freeze (HB);
8773 Set_Must_Not_Freeze (LB);
8774 Set_Must_Not_Freeze (Prefix (HB));
8775 Set_Must_Not_Freeze (Prefix (LB));
8778 if Raises_Constraint_Error (Prefix (N)) then
8780 -- Preserve Sloc of prefix in the new bounds, so that
8781 -- the posted warning can be removed if we are within
8782 -- unreachable code.
8784 Set_Sloc (LB, Sloc (Prefix (N)));
8785 Set_Sloc (HB, Sloc (Prefix (N)));
8788 Rewrite (N, Make_Range (Loc, LB, HB));
8789 Analyze_And_Resolve (N, Typ);
8791 -- Ensure that the expanded range does not have side effects
8793 Force_Evaluation (LB);
8794 Force_Evaluation (HB);
8796 -- Normally after resolving attribute nodes, Eval_Attribute
8797 -- is called to do any possible static evaluation of the node.
8798 -- However, here since the Range attribute has just been
8799 -- transformed into a range expression it is no longer an
8800 -- attribute node and therefore the call needs to be avoided
8801 -- and is accomplished by simply returning from the procedure.
8804 end Range_Attribute;
8810 -- We will only come here during the prescan of a spec expression
8811 -- containing a Result attribute. In that case the proper Etype has
8812 -- already been set, and nothing more needs to be done here.
8814 when Attribute_Result =>
8821 -- Prefix must not be resolved in this case, since it is not a
8822 -- real entity reference. No action of any kind is require!
8824 when Attribute_UET_Address =>
8827 ----------------------
8828 -- Unchecked_Access --
8829 ----------------------
8831 -- Processing is shared with Access
8833 -------------------------
8834 -- Unrestricted_Access --
8835 -------------------------
8837 -- Processing is shared with Access
8843 -- Apply range check. Note that we did not do this during the
8844 -- analysis phase, since we wanted Eval_Attribute to have a
8845 -- chance at finding an illegal out of range value.
8847 when Attribute_Val =>
8849 -- Note that we do our own Eval_Attribute call here rather than
8850 -- use the common one, because we need to do processing after
8851 -- the call, as per above comment.
8855 -- Eval_Attribute may replace the node with a raise CE, or
8856 -- fold it to a constant. Obviously we only apply a scalar
8857 -- range check if this did not happen!
8859 if Nkind (N) = N_Attribute_Reference
8860 and then Attribute_Name (N) = Name_Val
8862 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
8871 -- Prefix of Version attribute can be a subprogram name which
8872 -- must not be resolved, since this is not a call.
8874 when Attribute_Version =>
8877 ----------------------
8878 -- Other Attributes --
8879 ----------------------
8881 -- For other attributes, resolve prefix unless it is a type. If
8882 -- the attribute reference itself is a type name ('Base and 'Class)
8883 -- then this is only legal within a task or protected record.
8886 if not Is_Entity_Name (P)
8887 or else not Is_Type (Entity (P))
8892 -- If the attribute reference itself is a type name ('Base,
8893 -- 'Class) then this is only legal within a task or protected
8894 -- record. What is this all about ???
8896 if Is_Entity_Name (N)
8897 and then Is_Type (Entity (N))
8899 if Is_Concurrent_Type (Entity (N))
8900 and then In_Open_Scopes (Entity (P))
8905 ("invalid use of subtype name in expression or call", N);
8909 -- For attributes whose argument may be a string, complete
8910 -- resolution of argument now. This avoids premature expansion
8911 -- (and the creation of transient scopes) before the attribute
8912 -- reference is resolved.
8915 when Attribute_Value =>
8916 Resolve (First (Expressions (N)), Standard_String);
8918 when Attribute_Wide_Value =>
8919 Resolve (First (Expressions (N)), Standard_Wide_String);
8921 when Attribute_Wide_Wide_Value =>
8922 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
8924 when others => null;
8927 -- If the prefix of the attribute is a class-wide type then it
8928 -- will be expanded into a dispatching call to a predefined
8929 -- primitive. Therefore we must check for potential violation
8930 -- of such restriction.
8932 if Is_Class_Wide_Type (Etype (P)) then
8933 Check_Restriction (No_Dispatching_Calls, N);
8937 -- Normally the Freezing is done by Resolve but sometimes the Prefix
8938 -- is not resolved, in which case the freezing must be done now.
8940 Freeze_Expression (P);
8942 -- Finally perform static evaluation on the attribute reference
8945 end Resolve_Attribute;
8947 --------------------------------
8948 -- Stream_Attribute_Available --
8949 --------------------------------
8951 function Stream_Attribute_Available
8953 Nam : TSS_Name_Type;
8954 Partial_View : Node_Id := Empty) return Boolean
8956 Etyp : Entity_Id := Typ;
8958 -- Start of processing for Stream_Attribute_Available
8961 -- We need some comments in this body ???
8963 if Has_Stream_Attribute_Definition (Typ, Nam) then
8967 if Is_Class_Wide_Type (Typ) then
8968 return not Is_Limited_Type (Typ)
8969 or else Stream_Attribute_Available (Etype (Typ), Nam);
8972 if Nam = TSS_Stream_Input
8973 and then Is_Abstract_Type (Typ)
8974 and then not Is_Class_Wide_Type (Typ)
8979 if not (Is_Limited_Type (Typ)
8980 or else (Present (Partial_View)
8981 and then Is_Limited_Type (Partial_View)))
8986 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
8988 if Nam = TSS_Stream_Input
8989 and then Ada_Version >= Ada_2005
8990 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
8994 elsif Nam = TSS_Stream_Output
8995 and then Ada_Version >= Ada_2005
8996 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
9001 -- Case of Read and Write: check for attribute definition clause that
9002 -- applies to an ancestor type.
9004 while Etype (Etyp) /= Etyp loop
9005 Etyp := Etype (Etyp);
9007 if Has_Stream_Attribute_Definition (Etyp, Nam) then
9012 if Ada_Version < Ada_2005 then
9014 -- In Ada 95 mode, also consider a non-visible definition
9017 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
9020 and then Stream_Attribute_Available
9021 (Btyp, Nam, Partial_View => Typ);
9026 end Stream_Attribute_Available;