1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
28 with Atree; use Atree;
29 with Casing; use Casing;
30 with Checks; use Checks;
31 with Einfo; use Einfo;
32 with Errout; use Errout;
34 with Exp_Dist; use Exp_Dist;
35 with Exp_Util; use Exp_Util;
36 with Expander; use Expander;
37 with Freeze; use Freeze;
38 with Gnatvsn; use Gnatvsn;
39 with Itypes; use Itypes;
41 with Lib.Xref; use Lib.Xref;
42 with Nlists; use Nlists;
43 with Nmake; use Nmake;
45 with Restrict; use Restrict;
46 with Rident; use Rident;
47 with Rtsfind; use Rtsfind;
48 with Sdefault; use Sdefault;
50 with Sem_Aux; use Sem_Aux;
51 with Sem_Cat; use Sem_Cat;
52 with Sem_Ch6; use Sem_Ch6;
53 with Sem_Ch8; use Sem_Ch8;
54 with Sem_Ch10; use Sem_Ch10;
55 with Sem_Dist; use Sem_Dist;
56 with Sem_Elim; use Sem_Elim;
57 with Sem_Eval; use Sem_Eval;
58 with Sem_Res; use Sem_Res;
59 with Sem_Type; use Sem_Type;
60 with Sem_Util; use Sem_Util;
61 with Stand; use Stand;
62 with Sinfo; use Sinfo;
63 with Sinput; use Sinput;
64 with Stringt; use Stringt;
66 with Stylesw; use Stylesw;
67 with Targparm; use Targparm;
68 with Ttypes; use Ttypes;
69 with Tbuild; use Tbuild;
70 with Uintp; use Uintp;
71 with Urealp; use Urealp;
73 package body Sem_Attr is
75 True_Value : constant Uint := Uint_1;
76 False_Value : constant Uint := Uint_0;
77 -- Synonyms to be used when these constants are used as Boolean values
79 Bad_Attribute : exception;
80 -- Exception raised if an error is detected during attribute processing,
81 -- used so that we can abandon the processing so we don't run into
82 -- trouble with cascaded errors.
84 -- The following array is the list of attributes defined in the Ada 83 RM
85 -- that are not included in Ada 95, but still get recognized in GNAT.
87 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
93 Attribute_Constrained |
100 Attribute_First_Bit |
106 Attribute_Leading_Part |
108 Attribute_Machine_Emax |
109 Attribute_Machine_Emin |
110 Attribute_Machine_Mantissa |
111 Attribute_Machine_Overflows |
112 Attribute_Machine_Radix |
113 Attribute_Machine_Rounds |
119 Attribute_Safe_Emax |
120 Attribute_Safe_Large |
121 Attribute_Safe_Small |
124 Attribute_Storage_Size |
126 Attribute_Terminated |
129 Attribute_Width => True,
132 -- The following array is the list of attributes defined in the Ada 2005
133 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
134 -- but in Ada 95 they are considered to be implementation defined.
136 Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'(
137 Attribute_Machine_Rounding |
140 Attribute_Stream_Size |
141 Attribute_Wide_Wide_Width => True,
144 -- The following array contains all attributes that imply a modification
145 -- of their prefixes or result in an access value. Such prefixes can be
146 -- considered as lvalues.
148 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
149 Attribute_Class_Array'(
154 Attribute_Unchecked_Access |
155 Attribute_Unrestricted_Access => True,
158 -----------------------
159 -- Local_Subprograms --
160 -----------------------
162 procedure Eval_Attribute (N : Node_Id);
163 -- Performs compile time evaluation of attributes where possible, leaving
164 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
165 -- set, and replacing the node with a literal node if the value can be
166 -- computed at compile time. All static attribute references are folded,
167 -- as well as a number of cases of non-static attributes that can always
168 -- be computed at compile time (e.g. floating-point model attributes that
169 -- are applied to non-static subtypes). Of course in such cases, the
170 -- Is_Static_Expression flag will not be set on the resulting literal.
171 -- Note that the only required action of this procedure is to catch the
172 -- static expression cases as described in the RM. Folding of other cases
173 -- is done where convenient, but some additional non-static folding is in
174 -- N_Expand_Attribute_Reference in cases where this is more convenient.
176 function Is_Anonymous_Tagged_Base
180 -- For derived tagged types that constrain parent discriminants we build
181 -- an anonymous unconstrained base type. We need to recognize the relation
182 -- between the two when analyzing an access attribute for a constrained
183 -- component, before the full declaration for Typ has been analyzed, and
184 -- where therefore the prefix of the attribute does not match the enclosing
187 -----------------------
188 -- Analyze_Attribute --
189 -----------------------
191 procedure Analyze_Attribute (N : Node_Id) is
192 Loc : constant Source_Ptr := Sloc (N);
193 Aname : constant Name_Id := Attribute_Name (N);
194 P : constant Node_Id := Prefix (N);
195 Exprs : constant List_Id := Expressions (N);
196 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
201 -- Type of prefix after analysis
203 P_Base_Type : Entity_Id;
204 -- Base type of prefix after analysis
206 -----------------------
207 -- Local Subprograms --
208 -----------------------
210 procedure Analyze_Access_Attribute;
211 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
212 -- Internally, Id distinguishes which of the three cases is involved.
214 procedure Bad_Attribute_For_Predicate;
215 -- Output error message for use of a predicate (First, Last, Range) not
216 -- allowed with a type that has predicates. If the type is a generic
217 -- actual, then the message is a warning, and we generate code to raise
218 -- program error with an appropriate reason. No error message is given
219 -- for internally generated uses of the attributes.
221 procedure Check_Array_Or_Scalar_Type;
222 -- Common procedure used by First, Last, Range attribute to check
223 -- that the prefix is a constrained array or scalar type, or a name
224 -- of an array object, and that an argument appears only if appropriate
225 -- (i.e. only in the array case).
227 procedure Check_Array_Type;
228 -- Common semantic checks for all array attributes. Checks that the
229 -- prefix is a constrained array type or the name of an array object.
230 -- The error message for non-arrays is specialized appropriately.
232 procedure Check_Asm_Attribute;
233 -- Common semantic checks for Asm_Input and Asm_Output attributes
235 procedure Check_Component;
236 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
237 -- Position. Checks prefix is an appropriate selected component.
239 procedure Check_Decimal_Fixed_Point_Type;
240 -- Check that prefix of attribute N is a decimal fixed-point type
242 procedure Check_Dereference;
243 -- If the prefix of attribute is an object of an access type, then
244 -- introduce an explicit dereference, and adjust P_Type accordingly.
246 procedure Check_Discrete_Type;
247 -- Verify that prefix of attribute N is a discrete type
250 -- Check that no attribute arguments are present
252 procedure Check_Either_E0_Or_E1;
253 -- Check that there are zero or one attribute arguments present
256 -- Check that exactly one attribute argument is present
259 -- Check that two attribute arguments are present
261 procedure Check_Enum_Image;
262 -- If the prefix type is an enumeration type, set all its literals
263 -- as referenced, since the image function could possibly end up
264 -- referencing any of the literals indirectly. Same for Enum_Val.
266 procedure Check_Fixed_Point_Type;
267 -- Verify that prefix of attribute N is a fixed type
269 procedure Check_Fixed_Point_Type_0;
270 -- Verify that prefix of attribute N is a fixed type and that
271 -- no attribute expressions are present
273 procedure Check_Floating_Point_Type;
274 -- Verify that prefix of attribute N is a float type
276 procedure Check_Floating_Point_Type_0;
277 -- Verify that prefix of attribute N is a float type and that
278 -- no attribute expressions are present
280 procedure Check_Floating_Point_Type_1;
281 -- Verify that prefix of attribute N is a float type and that
282 -- exactly one attribute expression is present
284 procedure Check_Floating_Point_Type_2;
285 -- Verify that prefix of attribute N is a float type and that
286 -- two attribute expressions are present
288 procedure Legal_Formal_Attribute;
289 -- Common processing for attributes Definite and Has_Discriminants.
290 -- Checks that prefix is generic indefinite formal type.
292 procedure Check_Integer_Type;
293 -- Verify that prefix of attribute N is an integer type
295 procedure Check_Library_Unit;
296 -- Verify that prefix of attribute N is a library unit
298 procedure Check_Modular_Integer_Type;
299 -- Verify that prefix of attribute N is a modular integer type
301 procedure Check_Not_CPP_Type;
302 -- Check that P (the prefix of the attribute) is not an CPP type
303 -- for which no Ada predefined primitive is available.
305 procedure Check_Not_Incomplete_Type;
306 -- Check that P (the prefix of the attribute) is not an incomplete
307 -- type or a private type for which no full view has been given.
309 procedure Check_Object_Reference (P : Node_Id);
310 -- Check that P (the prefix of the attribute) is an object reference
312 procedure Check_Program_Unit;
313 -- Verify that prefix of attribute N is a program unit
315 procedure Check_Real_Type;
316 -- Verify that prefix of attribute N is fixed or float type
318 procedure Check_Scalar_Type;
319 -- Verify that prefix of attribute N is a scalar type
321 procedure Check_Standard_Prefix;
322 -- Verify that prefix of attribute N is package Standard
324 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
325 -- Validity checking for stream attribute. Nam is the TSS name of the
326 -- corresponding possible defined attribute function (e.g. for the
327 -- Read attribute, Nam will be TSS_Stream_Read).
329 procedure Check_PolyORB_Attribute;
330 -- Validity checking for PolyORB/DSA attribute
332 procedure Check_Task_Prefix;
333 -- Verify that prefix of attribute N is a task or task type
335 procedure Check_Type;
336 -- Verify that the prefix of attribute N is a type
338 procedure Check_Unit_Name (Nod : Node_Id);
339 -- Check that Nod is of the form of a library unit name, i.e that
340 -- it is an identifier, or a selected component whose prefix is
341 -- itself of the form of a library unit name. Note that this is
342 -- quite different from Check_Program_Unit, since it only checks
343 -- the syntactic form of the name, not the semantic identity. This
344 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
345 -- UET_Address) which can refer to non-visible unit.
347 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
348 pragma No_Return (Error_Attr);
349 procedure Error_Attr;
350 pragma No_Return (Error_Attr);
351 -- Posts error using Error_Msg_N at given node, sets type of attribute
352 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
353 -- semantic processing. The message typically contains a % insertion
354 -- character which is replaced by the attribute name. The call with
355 -- no arguments is used when the caller has already generated the
356 -- required error messages.
358 procedure Error_Attr_P (Msg : String);
359 pragma No_Return (Error_Attr);
360 -- Like Error_Attr, but error is posted at the start of the prefix
362 procedure Standard_Attribute (Val : Int);
363 -- Used to process attributes whose prefix is package Standard which
364 -- yield values of type Universal_Integer. The attribute reference
365 -- node is rewritten with an integer literal of the given value.
367 procedure Unexpected_Argument (En : Node_Id);
368 -- Signal unexpected attribute argument (En is the argument)
370 procedure Validate_Non_Static_Attribute_Function_Call;
371 -- Called when processing an attribute that is a function call to a
372 -- non-static function, i.e. an attribute function that either takes
373 -- non-scalar arguments or returns a non-scalar result. Verifies that
374 -- such a call does not appear in a preelaborable context.
376 ------------------------------
377 -- Analyze_Access_Attribute --
378 ------------------------------
380 procedure Analyze_Access_Attribute is
381 Acc_Type : Entity_Id;
386 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
387 -- Build an access-to-object type whose designated type is DT,
388 -- and whose Ekind is appropriate to the attribute type. The
389 -- type that is constructed is returned as the result.
391 procedure Build_Access_Subprogram_Type (P : Node_Id);
392 -- Build an access to subprogram whose designated type is the type of
393 -- the prefix. If prefix is overloaded, so is the node itself. The
394 -- result is stored in Acc_Type.
396 function OK_Self_Reference return Boolean;
397 -- An access reference whose prefix is a type can legally appear
398 -- within an aggregate, where it is obtained by expansion of
399 -- a defaulted aggregate. The enclosing aggregate that contains
400 -- the self-referenced is flagged so that the self-reference can
401 -- be expanded into a reference to the target object (see exp_aggr).
403 ------------------------------
404 -- Build_Access_Object_Type --
405 ------------------------------
407 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
408 Typ : constant Entity_Id :=
410 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
412 Set_Etype (Typ, Typ);
414 Set_Associated_Node_For_Itype (Typ, N);
415 Set_Directly_Designated_Type (Typ, DT);
417 end Build_Access_Object_Type;
419 ----------------------------------
420 -- Build_Access_Subprogram_Type --
421 ----------------------------------
423 procedure Build_Access_Subprogram_Type (P : Node_Id) is
424 Index : Interp_Index;
427 procedure Check_Local_Access (E : Entity_Id);
428 -- Deal with possible access to local subprogram. If we have such
429 -- an access, we set a flag to kill all tracked values on any call
430 -- because this access value may be passed around, and any called
431 -- code might use it to access a local procedure which clobbers a
432 -- tracked value. If the scope is a loop or block, indicate that
433 -- value tracking is disabled for the enclosing subprogram.
435 function Get_Kind (E : Entity_Id) return Entity_Kind;
436 -- Distinguish between access to regular/protected subprograms
438 ------------------------
439 -- Check_Local_Access --
440 ------------------------
442 procedure Check_Local_Access (E : Entity_Id) is
444 if not Is_Library_Level_Entity (E) then
445 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
446 Set_Suppress_Value_Tracking_On_Call
447 (Nearest_Dynamic_Scope (Current_Scope));
449 end Check_Local_Access;
455 function Get_Kind (E : Entity_Id) return Entity_Kind is
457 if Convention (E) = Convention_Protected then
458 return E_Access_Protected_Subprogram_Type;
460 return E_Access_Subprogram_Type;
464 -- Start of processing for Build_Access_Subprogram_Type
467 -- In the case of an access to subprogram, use the name of the
468 -- subprogram itself as the designated type. Type-checking in
469 -- this case compares the signatures of the designated types.
471 -- Note: This fragment of the tree is temporarily malformed
472 -- because the correct tree requires an E_Subprogram_Type entity
473 -- as the designated type. In most cases this designated type is
474 -- later overridden by the semantics with the type imposed by the
475 -- context during the resolution phase. In the specific case of
476 -- the expression Address!(Prim'Unrestricted_Access), used to
477 -- initialize slots of dispatch tables, this work will be done by
478 -- the expander (see Exp_Aggr).
480 -- The reason to temporarily add this kind of node to the tree
481 -- instead of a proper E_Subprogram_Type itype, is the following:
482 -- in case of errors found in the source file we report better
483 -- error messages. For example, instead of generating the
486 -- "expected access to subprogram with profile
487 -- defined at line X"
489 -- we currently generate:
491 -- "expected access to function Z defined at line X"
493 Set_Etype (N, Any_Type);
495 if not Is_Overloaded (P) then
496 Check_Local_Access (Entity (P));
498 if not Is_Intrinsic_Subprogram (Entity (P)) then
499 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
500 Set_Is_Public (Acc_Type, False);
501 Set_Etype (Acc_Type, Acc_Type);
502 Set_Convention (Acc_Type, Convention (Entity (P)));
503 Set_Directly_Designated_Type (Acc_Type, Entity (P));
504 Set_Etype (N, Acc_Type);
505 Freeze_Before (N, Acc_Type);
509 Get_First_Interp (P, Index, It);
510 while Present (It.Nam) loop
511 Check_Local_Access (It.Nam);
513 if not Is_Intrinsic_Subprogram (It.Nam) then
514 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
515 Set_Is_Public (Acc_Type, False);
516 Set_Etype (Acc_Type, Acc_Type);
517 Set_Convention (Acc_Type, Convention (It.Nam));
518 Set_Directly_Designated_Type (Acc_Type, It.Nam);
519 Add_One_Interp (N, Acc_Type, Acc_Type);
520 Freeze_Before (N, Acc_Type);
523 Get_Next_Interp (Index, It);
527 -- Cannot be applied to intrinsic. Looking at the tests above,
528 -- the only way Etype (N) can still be set to Any_Type is if
529 -- Is_Intrinsic_Subprogram was True for some referenced entity.
531 if Etype (N) = Any_Type then
532 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
534 end Build_Access_Subprogram_Type;
536 ----------------------
537 -- OK_Self_Reference --
538 ----------------------
540 function OK_Self_Reference return Boolean is
547 (Nkind (Par) = N_Component_Association
548 or else Nkind (Par) in N_Subexpr)
550 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
551 if Etype (Par) = Typ then
552 Set_Has_Self_Reference (Par);
560 -- No enclosing aggregate, or not a self-reference
563 end OK_Self_Reference;
565 -- Start of processing for Analyze_Access_Attribute
570 if Nkind (P) = N_Character_Literal then
572 ("prefix of % attribute cannot be enumeration literal");
575 -- Case of access to subprogram
577 if Is_Entity_Name (P)
578 and then Is_Overloadable (Entity (P))
580 if Has_Pragma_Inline_Always (Entity (P)) then
582 ("prefix of % attribute cannot be Inline_Always subprogram");
585 if Aname = Name_Unchecked_Access then
586 Error_Attr ("attribute% cannot be applied to a subprogram", P);
589 -- Issue an error if the prefix denotes an eliminated subprogram
591 Check_For_Eliminated_Subprogram (P, Entity (P));
593 -- Check for obsolescent subprogram reference
595 Check_Obsolescent_2005_Entity (Entity (P), P);
597 -- Build the appropriate subprogram type
599 Build_Access_Subprogram_Type (P);
601 -- For unrestricted access, kill current values, since this
602 -- attribute allows a reference to a local subprogram that
603 -- could modify local variables to be passed out of scope
605 if Aname = Name_Unrestricted_Access then
607 -- Do not kill values on nodes initializing dispatch tables
608 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
609 -- is currently generated by the expander only for this
610 -- purpose. Done to keep the quality of warnings currently
611 -- generated by the compiler (otherwise any declaration of
612 -- a tagged type cleans constant indications from its scope).
614 if Nkind (Parent (N)) = N_Unchecked_Type_Conversion
615 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
617 Etype (Parent (N)) = RTE (RE_Size_Ptr))
618 and then Is_Dispatching_Operation
619 (Directly_Designated_Type (Etype (N)))
629 -- Component is an operation of a protected type
631 elsif Nkind (P) = N_Selected_Component
632 and then Is_Overloadable (Entity (Selector_Name (P)))
634 if Ekind (Entity (Selector_Name (P))) = E_Entry then
635 Error_Attr_P ("prefix of % attribute must be subprogram");
638 Build_Access_Subprogram_Type (Selector_Name (P));
642 -- Deal with incorrect reference to a type, but note that some
643 -- accesses are allowed: references to the current type instance,
644 -- or in Ada 2005 self-referential pointer in a default-initialized
647 if Is_Entity_Name (P) then
650 -- The reference may appear in an aggregate that has been expanded
651 -- into a loop. Locate scope of type definition, if any.
653 Scop := Current_Scope;
654 while Ekind (Scop) = E_Loop loop
655 Scop := Scope (Scop);
658 if Is_Type (Typ) then
660 -- OK if we are within the scope of a limited type
661 -- let's mark the component as having per object constraint
663 if Is_Anonymous_Tagged_Base (Scop, Typ) then
671 Q : Node_Id := Parent (N);
675 and then Nkind (Q) /= N_Component_Declaration
681 Set_Has_Per_Object_Constraint
682 (Defining_Identifier (Q), True);
686 if Nkind (P) = N_Expanded_Name then
688 ("current instance prefix must be a direct name", P);
691 -- If a current instance attribute appears in a component
692 -- constraint it must appear alone; other contexts (spec-
693 -- expressions, within a task body) are not subject to this
696 if not In_Spec_Expression
697 and then not Has_Completion (Scop)
699 Nkind_In (Parent (N), N_Discriminant_Association,
700 N_Index_Or_Discriminant_Constraint)
703 ("current instance attribute must appear alone", N);
706 if Is_CPP_Class (Root_Type (Typ)) then
708 ("?current instance unsupported for derivations of "
709 & "'C'P'P types", N);
712 -- OK if we are in initialization procedure for the type
713 -- in question, in which case the reference to the type
714 -- is rewritten as a reference to the current object.
716 elsif Ekind (Scop) = E_Procedure
717 and then Is_Init_Proc (Scop)
718 and then Etype (First_Formal (Scop)) = Typ
721 Make_Attribute_Reference (Loc,
722 Prefix => Make_Identifier (Loc, Name_uInit),
723 Attribute_Name => Name_Unrestricted_Access));
727 -- OK if a task type, this test needs sharpening up ???
729 elsif Is_Task_Type (Typ) then
732 -- OK if self-reference in an aggregate in Ada 2005, and
733 -- the reference comes from a copied default expression.
735 -- Note that we check legality of self-reference even if the
736 -- expression comes from source, e.g. when a single component
737 -- association in an aggregate has a box association.
739 elsif Ada_Version >= Ada_2005
740 and then OK_Self_Reference
744 -- OK if reference to current instance of a protected object
746 elsif Is_Protected_Self_Reference (P) then
749 -- Otherwise we have an error case
752 Error_Attr ("% attribute cannot be applied to type", P);
758 -- If we fall through, we have a normal access to object case.
759 -- Unrestricted_Access is legal wherever an allocator would be
760 -- legal, so its Etype is set to E_Allocator. The expected type
761 -- of the other attributes is a general access type, and therefore
762 -- we label them with E_Access_Attribute_Type.
764 if not Is_Overloaded (P) then
765 Acc_Type := Build_Access_Object_Type (P_Type);
766 Set_Etype (N, Acc_Type);
769 Index : Interp_Index;
772 Set_Etype (N, Any_Type);
773 Get_First_Interp (P, Index, It);
774 while Present (It.Typ) loop
775 Acc_Type := Build_Access_Object_Type (It.Typ);
776 Add_One_Interp (N, Acc_Type, Acc_Type);
777 Get_Next_Interp (Index, It);
782 -- Special cases when we can find a prefix that is an entity name
791 if Is_Entity_Name (PP) then
794 -- If we have an access to an object, and the attribute
795 -- comes from source, then set the object as potentially
796 -- source modified. We do this because the resulting access
797 -- pointer can be used to modify the variable, and we might
798 -- not detect this, leading to some junk warnings.
800 Set_Never_Set_In_Source (Ent, False);
802 -- Mark entity as address taken, and kill current values
804 Set_Address_Taken (Ent);
805 Kill_Current_Values (Ent);
808 elsif Nkind_In (PP, N_Selected_Component,
819 -- Check for aliased view unless unrestricted case. We allow a
820 -- nonaliased prefix when within an instance because the prefix may
821 -- have been a tagged formal object, which is defined to be aliased
822 -- even when the actual might not be (other instance cases will have
823 -- been caught in the generic). Similarly, within an inlined body we
824 -- know that the attribute is legal in the original subprogram, and
825 -- therefore legal in the expansion.
827 if Aname /= Name_Unrestricted_Access
828 and then not Is_Aliased_View (P)
829 and then not In_Instance
830 and then not In_Inlined_Body
832 Error_Attr_P ("prefix of % attribute must be aliased");
834 end Analyze_Access_Attribute;
836 ---------------------------------
837 -- Bad_Attribute_For_Predicate --
838 ---------------------------------
840 procedure Bad_Attribute_For_Predicate is
842 if Comes_From_Source (N) then
843 Error_Msg_Name_1 := Aname;
844 Bad_Predicated_Subtype_Use
845 ("type& has predicates, attribute % not allowed", N, P_Type);
847 end Bad_Attribute_For_Predicate;
849 --------------------------------
850 -- Check_Array_Or_Scalar_Type --
851 --------------------------------
853 procedure Check_Array_Or_Scalar_Type is
857 -- Dimension number for array attributes
860 -- Case of string literal or string literal subtype. These cases
861 -- cannot arise from legal Ada code, but the expander is allowed
862 -- to generate them. They require special handling because string
863 -- literal subtypes do not have standard bounds (the whole idea
864 -- of these subtypes is to avoid having to generate the bounds)
866 if Ekind (P_Type) = E_String_Literal_Subtype then
867 Set_Etype (N, Etype (First_Index (P_Base_Type)));
872 elsif Is_Scalar_Type (P_Type) then
876 Error_Attr ("invalid argument in % attribute", E1);
878 Set_Etype (N, P_Base_Type);
882 -- The following is a special test to allow 'First to apply to
883 -- private scalar types if the attribute comes from generated
884 -- code. This occurs in the case of Normalize_Scalars code.
886 elsif Is_Private_Type (P_Type)
887 and then Present (Full_View (P_Type))
888 and then Is_Scalar_Type (Full_View (P_Type))
889 and then not Comes_From_Source (N)
891 Set_Etype (N, Implementation_Base_Type (P_Type));
893 -- Array types other than string literal subtypes handled above
898 -- We know prefix is an array type, or the name of an array
899 -- object, and that the expression, if present, is static
900 -- and within the range of the dimensions of the type.
902 pragma Assert (Is_Array_Type (P_Type));
903 Index := First_Index (P_Base_Type);
907 -- First dimension assumed
909 Set_Etype (N, Base_Type (Etype (Index)));
912 D := UI_To_Int (Intval (E1));
914 for J in 1 .. D - 1 loop
918 Set_Etype (N, Base_Type (Etype (Index)));
919 Set_Etype (E1, Standard_Integer);
922 end Check_Array_Or_Scalar_Type;
924 ----------------------
925 -- Check_Array_Type --
926 ----------------------
928 procedure Check_Array_Type is
930 -- Dimension number for array attributes
933 -- If the type is a string literal type, then this must be generated
934 -- internally, and no further check is required on its legality.
936 if Ekind (P_Type) = E_String_Literal_Subtype then
939 -- If the type is a composite, it is an illegal aggregate, no point
942 elsif P_Type = Any_Composite then
946 -- Normal case of array type or subtype
948 Check_Either_E0_Or_E1;
951 if Is_Array_Type (P_Type) then
952 if not Is_Constrained (P_Type)
953 and then Is_Entity_Name (P)
954 and then Is_Type (Entity (P))
956 -- Note: we do not call Error_Attr here, since we prefer to
957 -- continue, using the relevant index type of the array,
958 -- even though it is unconstrained. This gives better error
959 -- recovery behavior.
961 Error_Msg_Name_1 := Aname;
963 ("prefix for % attribute must be constrained array", P);
966 D := Number_Dimensions (P_Type);
969 if Is_Private_Type (P_Type) then
970 Error_Attr_P ("prefix for % attribute may not be private type");
972 elsif Is_Access_Type (P_Type)
973 and then Is_Array_Type (Designated_Type (P_Type))
974 and then Is_Entity_Name (P)
975 and then Is_Type (Entity (P))
977 Error_Attr_P ("prefix of % attribute cannot be access type");
979 elsif Attr_Id = Attribute_First
981 Attr_Id = Attribute_Last
983 Error_Attr ("invalid prefix for % attribute", P);
986 Error_Attr_P ("prefix for % attribute must be array");
991 Resolve (E1, Any_Integer);
992 Set_Etype (E1, Standard_Integer);
994 if not Is_Static_Expression (E1)
995 or else Raises_Constraint_Error (E1)
998 ("expression for dimension must be static!", E1);
1001 elsif UI_To_Int (Expr_Value (E1)) > D
1002 or else UI_To_Int (Expr_Value (E1)) < 1
1004 Error_Attr ("invalid dimension number for array type", E1);
1008 if (Style_Check and Style_Check_Array_Attribute_Index)
1009 and then Comes_From_Source (N)
1011 Style.Check_Array_Attribute_Index (N, E1, D);
1013 end Check_Array_Type;
1015 -------------------------
1016 -- Check_Asm_Attribute --
1017 -------------------------
1019 procedure Check_Asm_Attribute is
1024 -- Check first argument is static string expression
1026 Analyze_And_Resolve (E1, Standard_String);
1028 if Etype (E1) = Any_Type then
1031 elsif not Is_OK_Static_Expression (E1) then
1032 Flag_Non_Static_Expr
1033 ("constraint argument must be static string expression!", E1);
1037 -- Check second argument is right type
1039 Analyze_And_Resolve (E2, Entity (P));
1041 -- Note: that is all we need to do, we don't need to check
1042 -- that it appears in a correct context. The Ada type system
1043 -- will do that for us.
1045 end Check_Asm_Attribute;
1047 ---------------------
1048 -- Check_Component --
1049 ---------------------
1051 procedure Check_Component is
1055 if Nkind (P) /= N_Selected_Component
1057 (Ekind (Entity (Selector_Name (P))) /= E_Component
1059 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1061 Error_Attr_P ("prefix for % attribute must be selected component");
1063 end Check_Component;
1065 ------------------------------------
1066 -- Check_Decimal_Fixed_Point_Type --
1067 ------------------------------------
1069 procedure Check_Decimal_Fixed_Point_Type is
1073 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1074 Error_Attr_P ("prefix of % attribute must be decimal type");
1076 end Check_Decimal_Fixed_Point_Type;
1078 -----------------------
1079 -- Check_Dereference --
1080 -----------------------
1082 procedure Check_Dereference is
1085 -- Case of a subtype mark
1087 if Is_Entity_Name (P)
1088 and then Is_Type (Entity (P))
1093 -- Case of an expression
1097 if Is_Access_Type (P_Type) then
1099 -- If there is an implicit dereference, then we must freeze
1100 -- the designated type of the access type, since the type of
1101 -- the referenced array is this type (see AI95-00106).
1103 -- As done elsewhere, freezing must not happen when pre-analyzing
1104 -- a pre- or postcondition or a default value for an object or
1105 -- for a formal parameter.
1107 if not In_Spec_Expression then
1108 Freeze_Before (N, Designated_Type (P_Type));
1112 Make_Explicit_Dereference (Sloc (P),
1113 Prefix => Relocate_Node (P)));
1115 Analyze_And_Resolve (P);
1116 P_Type := Etype (P);
1118 if P_Type = Any_Type then
1119 raise Bad_Attribute;
1122 P_Base_Type := Base_Type (P_Type);
1124 end Check_Dereference;
1126 -------------------------
1127 -- Check_Discrete_Type --
1128 -------------------------
1130 procedure Check_Discrete_Type is
1134 if not Is_Discrete_Type (P_Type) then
1135 Error_Attr_P ("prefix of % attribute must be discrete type");
1137 end Check_Discrete_Type;
1143 procedure Check_E0 is
1145 if Present (E1) then
1146 Unexpected_Argument (E1);
1154 procedure Check_E1 is
1156 Check_Either_E0_Or_E1;
1160 -- Special-case attributes that are functions and that appear as
1161 -- the prefix of another attribute. Error is posted on parent.
1163 if Nkind (Parent (N)) = N_Attribute_Reference
1164 and then (Attribute_Name (Parent (N)) = Name_Address
1166 Attribute_Name (Parent (N)) = Name_Code_Address
1168 Attribute_Name (Parent (N)) = Name_Access)
1170 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1171 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1172 Set_Etype (Parent (N), Any_Type);
1173 Set_Entity (Parent (N), Any_Type);
1174 raise Bad_Attribute;
1177 Error_Attr ("missing argument for % attribute", N);
1186 procedure Check_E2 is
1189 Error_Attr ("missing arguments for % attribute (2 required)", N);
1191 Error_Attr ("missing argument for % attribute (2 required)", N);
1195 ---------------------------
1196 -- Check_Either_E0_Or_E1 --
1197 ---------------------------
1199 procedure Check_Either_E0_Or_E1 is
1201 if Present (E2) then
1202 Unexpected_Argument (E2);
1204 end Check_Either_E0_Or_E1;
1206 ----------------------
1207 -- Check_Enum_Image --
1208 ----------------------
1210 procedure Check_Enum_Image is
1213 if Is_Enumeration_Type (P_Base_Type) then
1214 Lit := First_Literal (P_Base_Type);
1215 while Present (Lit) loop
1216 Set_Referenced (Lit);
1220 end Check_Enum_Image;
1222 ----------------------------
1223 -- Check_Fixed_Point_Type --
1224 ----------------------------
1226 procedure Check_Fixed_Point_Type is
1230 if not Is_Fixed_Point_Type (P_Type) then
1231 Error_Attr_P ("prefix of % attribute must be fixed point type");
1233 end Check_Fixed_Point_Type;
1235 ------------------------------
1236 -- Check_Fixed_Point_Type_0 --
1237 ------------------------------
1239 procedure Check_Fixed_Point_Type_0 is
1241 Check_Fixed_Point_Type;
1243 end Check_Fixed_Point_Type_0;
1245 -------------------------------
1246 -- Check_Floating_Point_Type --
1247 -------------------------------
1249 procedure Check_Floating_Point_Type is
1253 if not Is_Floating_Point_Type (P_Type) then
1254 Error_Attr_P ("prefix of % attribute must be float type");
1256 end Check_Floating_Point_Type;
1258 ---------------------------------
1259 -- Check_Floating_Point_Type_0 --
1260 ---------------------------------
1262 procedure Check_Floating_Point_Type_0 is
1264 Check_Floating_Point_Type;
1266 end Check_Floating_Point_Type_0;
1268 ---------------------------------
1269 -- Check_Floating_Point_Type_1 --
1270 ---------------------------------
1272 procedure Check_Floating_Point_Type_1 is
1274 Check_Floating_Point_Type;
1276 end Check_Floating_Point_Type_1;
1278 ---------------------------------
1279 -- Check_Floating_Point_Type_2 --
1280 ---------------------------------
1282 procedure Check_Floating_Point_Type_2 is
1284 Check_Floating_Point_Type;
1286 end Check_Floating_Point_Type_2;
1288 ------------------------
1289 -- Check_Integer_Type --
1290 ------------------------
1292 procedure Check_Integer_Type is
1296 if not Is_Integer_Type (P_Type) then
1297 Error_Attr_P ("prefix of % attribute must be integer type");
1299 end Check_Integer_Type;
1301 ------------------------
1302 -- Check_Library_Unit --
1303 ------------------------
1305 procedure Check_Library_Unit is
1307 if not Is_Compilation_Unit (Entity (P)) then
1308 Error_Attr_P ("prefix of % attribute must be library unit");
1310 end Check_Library_Unit;
1312 --------------------------------
1313 -- Check_Modular_Integer_Type --
1314 --------------------------------
1316 procedure Check_Modular_Integer_Type is
1320 if not Is_Modular_Integer_Type (P_Type) then
1322 ("prefix of % attribute must be modular integer type");
1324 end Check_Modular_Integer_Type;
1326 ------------------------
1327 -- Check_Not_CPP_Type --
1328 ------------------------
1330 procedure Check_Not_CPP_Type is
1332 if Is_Tagged_Type (Etype (P))
1333 and then Convention (Etype (P)) = Convention_CPP
1334 and then Is_CPP_Class (Root_Type (Etype (P)))
1337 ("invalid use of % attribute with 'C'P'P tagged type");
1339 end Check_Not_CPP_Type;
1341 -------------------------------
1342 -- Check_Not_Incomplete_Type --
1343 -------------------------------
1345 procedure Check_Not_Incomplete_Type is
1350 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1351 -- dereference we have to check wrong uses of incomplete types
1352 -- (other wrong uses are checked at their freezing point).
1354 -- Example 1: Limited-with
1356 -- limited with Pkg;
1358 -- type Acc is access Pkg.T;
1360 -- S : Integer := X.all'Size; -- ERROR
1363 -- Example 2: Tagged incomplete
1365 -- type T is tagged;
1366 -- type Acc is access all T;
1368 -- S : constant Integer := X.all'Size; -- ERROR
1369 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1371 if Ada_Version >= Ada_2005
1372 and then Nkind (P) = N_Explicit_Dereference
1375 while Nkind (E) = N_Explicit_Dereference loop
1381 if From_With_Type (Typ) then
1383 ("prefix of % attribute cannot be an incomplete type");
1386 if Is_Access_Type (Typ) then
1387 Typ := Directly_Designated_Type (Typ);
1390 if Is_Class_Wide_Type (Typ) then
1391 Typ := Root_Type (Typ);
1394 -- A legal use of a shadow entity occurs only when the unit
1395 -- where the non-limited view resides is imported via a regular
1396 -- with clause in the current body. Such references to shadow
1397 -- entities may occur in subprogram formals.
1399 if Is_Incomplete_Type (Typ)
1400 and then From_With_Type (Typ)
1401 and then Present (Non_Limited_View (Typ))
1402 and then Is_Legal_Shadow_Entity_In_Body (Typ)
1404 Typ := Non_Limited_View (Typ);
1407 if Ekind (Typ) = E_Incomplete_Type
1408 and then No (Full_View (Typ))
1411 ("prefix of % attribute cannot be an incomplete type");
1416 if not Is_Entity_Name (P)
1417 or else not Is_Type (Entity (P))
1418 or else In_Spec_Expression
1422 Check_Fully_Declared (P_Type, P);
1424 end Check_Not_Incomplete_Type;
1426 ----------------------------
1427 -- Check_Object_Reference --
1428 ----------------------------
1430 procedure Check_Object_Reference (P : Node_Id) is
1434 -- If we need an object, and we have a prefix that is the name of
1435 -- a function entity, convert it into a function call.
1437 if Is_Entity_Name (P)
1438 and then Ekind (Entity (P)) = E_Function
1440 Rtyp := Etype (Entity (P));
1443 Make_Function_Call (Sloc (P),
1444 Name => Relocate_Node (P)));
1446 Analyze_And_Resolve (P, Rtyp);
1448 -- Otherwise we must have an object reference
1450 elsif not Is_Object_Reference (P) then
1451 Error_Attr_P ("prefix of % attribute must be object");
1453 end Check_Object_Reference;
1455 ----------------------------
1456 -- Check_PolyORB_Attribute --
1457 ----------------------------
1459 procedure Check_PolyORB_Attribute is
1461 Validate_Non_Static_Attribute_Function_Call;
1466 if Get_PCS_Name /= Name_PolyORB_DSA then
1468 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
1470 end Check_PolyORB_Attribute;
1472 ------------------------
1473 -- Check_Program_Unit --
1474 ------------------------
1476 procedure Check_Program_Unit is
1478 if Is_Entity_Name (P) then
1480 K : constant Entity_Kind := Ekind (Entity (P));
1481 T : constant Entity_Id := Etype (Entity (P));
1484 if K in Subprogram_Kind
1485 or else K in Task_Kind
1486 or else K in Protected_Kind
1487 or else K = E_Package
1488 or else K in Generic_Unit_Kind
1489 or else (K = E_Variable
1493 Is_Protected_Type (T)))
1500 Error_Attr_P ("prefix of % attribute must be program unit");
1501 end Check_Program_Unit;
1503 ---------------------
1504 -- Check_Real_Type --
1505 ---------------------
1507 procedure Check_Real_Type is
1511 if not Is_Real_Type (P_Type) then
1512 Error_Attr_P ("prefix of % attribute must be real type");
1514 end Check_Real_Type;
1516 -----------------------
1517 -- Check_Scalar_Type --
1518 -----------------------
1520 procedure Check_Scalar_Type is
1524 if not Is_Scalar_Type (P_Type) then
1525 Error_Attr_P ("prefix of % attribute must be scalar type");
1527 end Check_Scalar_Type;
1529 ---------------------------
1530 -- Check_Standard_Prefix --
1531 ---------------------------
1533 procedure Check_Standard_Prefix is
1537 if Nkind (P) /= N_Identifier
1538 or else Chars (P) /= Name_Standard
1540 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1542 end Check_Standard_Prefix;
1544 ----------------------------
1545 -- Check_Stream_Attribute --
1546 ----------------------------
1548 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1552 In_Shared_Var_Procs : Boolean;
1553 -- True when compiling the body of System.Shared_Storage.
1554 -- Shared_Var_Procs. For this runtime package (always compiled in
1555 -- GNAT mode), we allow stream attributes references for limited
1556 -- types for the case where shared passive objects are implemented
1557 -- using stream attributes, which is the default in GNAT's persistent
1558 -- storage implementation.
1561 Validate_Non_Static_Attribute_Function_Call;
1563 -- With the exception of 'Input, Stream attributes are procedures,
1564 -- and can only appear at the position of procedure calls. We check
1565 -- for this here, before they are rewritten, to give a more precise
1568 if Nam = TSS_Stream_Input then
1571 elsif Is_List_Member (N)
1572 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
1579 ("invalid context for attribute%, which is a procedure", N);
1583 Btyp := Implementation_Base_Type (P_Type);
1585 -- Stream attributes not allowed on limited types unless the
1586 -- attribute reference was generated by the expander (in which
1587 -- case the underlying type will be used, as described in Sinfo),
1588 -- or the attribute was specified explicitly for the type itself
1589 -- or one of its ancestors (taking visibility rules into account if
1590 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
1591 -- (with no visibility restriction).
1594 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
1596 if Present (Gen_Body) then
1597 In_Shared_Var_Procs :=
1598 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
1600 In_Shared_Var_Procs := False;
1604 if (Comes_From_Source (N)
1605 and then not (In_Shared_Var_Procs or In_Instance))
1606 and then not Stream_Attribute_Available (P_Type, Nam)
1607 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
1609 Error_Msg_Name_1 := Aname;
1611 if Is_Limited_Type (P_Type) then
1613 ("limited type& has no% attribute", P, P_Type);
1614 Explain_Limited_Type (P_Type, P);
1617 ("attribute% for type& is not available", P, P_Type);
1621 -- Check restriction violations
1623 -- First check the No_Streams restriction, which prohibits the use
1624 -- of explicit stream attributes in the source program. We do not
1625 -- prevent the occurrence of stream attributes in generated code,
1626 -- for instance those generated implicitly for dispatching purposes.
1628 if Comes_From_Source (N) then
1629 Check_Restriction (No_Streams, P);
1632 -- Check special case of Exception_Id and Exception_Occurrence which
1633 -- are not allowed for restriction No_Exception_Registration.
1635 if Is_RTE (P_Type, RE_Exception_Id)
1637 Is_RTE (P_Type, RE_Exception_Occurrence)
1639 Check_Restriction (No_Exception_Registration, P);
1642 -- Here we must check that the first argument is an access type
1643 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1645 Analyze_And_Resolve (E1);
1648 -- Note: the double call to Root_Type here is needed because the
1649 -- root type of a class-wide type is the corresponding type (e.g.
1650 -- X for X'Class, and we really want to go to the root.)
1652 if not Is_Access_Type (Etyp)
1653 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1654 RTE (RE_Root_Stream_Type)
1657 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1660 -- Check that the second argument is of the right type if there is
1661 -- one (the Input attribute has only one argument so this is skipped)
1663 if Present (E2) then
1666 if Nam = TSS_Stream_Read
1667 and then not Is_OK_Variable_For_Out_Formal (E2)
1670 ("second argument of % attribute must be a variable", E2);
1673 Resolve (E2, P_Type);
1677 end Check_Stream_Attribute;
1679 -----------------------
1680 -- Check_Task_Prefix --
1681 -----------------------
1683 procedure Check_Task_Prefix is
1687 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1688 -- task interface class-wide types.
1690 if Is_Task_Type (Etype (P))
1691 or else (Is_Access_Type (Etype (P))
1692 and then Is_Task_Type (Designated_Type (Etype (P))))
1693 or else (Ada_Version >= Ada_2005
1694 and then Ekind (Etype (P)) = E_Class_Wide_Type
1695 and then Is_Interface (Etype (P))
1696 and then Is_Task_Interface (Etype (P)))
1701 if Ada_Version >= Ada_2005 then
1703 ("prefix of % attribute must be a task or a task " &
1704 "interface class-wide object");
1707 Error_Attr_P ("prefix of % attribute must be a task");
1710 end Check_Task_Prefix;
1716 -- The possibilities are an entity name denoting a type, or an
1717 -- attribute reference that denotes a type (Base or Class). If
1718 -- the type is incomplete, replace it with its full view.
1720 procedure Check_Type is
1722 if not Is_Entity_Name (P)
1723 or else not Is_Type (Entity (P))
1725 Error_Attr_P ("prefix of % attribute must be a type");
1727 elsif Is_Protected_Self_Reference (P) then
1729 ("prefix of % attribute denotes current instance "
1730 & "(RM 9.4(21/2))");
1732 elsif Ekind (Entity (P)) = E_Incomplete_Type
1733 and then Present (Full_View (Entity (P)))
1735 P_Type := Full_View (Entity (P));
1736 Set_Entity (P, P_Type);
1740 ---------------------
1741 -- Check_Unit_Name --
1742 ---------------------
1744 procedure Check_Unit_Name (Nod : Node_Id) is
1746 if Nkind (Nod) = N_Identifier then
1749 elsif Nkind (Nod) = N_Selected_Component then
1750 Check_Unit_Name (Prefix (Nod));
1752 if Nkind (Selector_Name (Nod)) = N_Identifier then
1757 Error_Attr ("argument for % attribute must be unit name", P);
1758 end Check_Unit_Name;
1764 procedure Error_Attr is
1766 Set_Etype (N, Any_Type);
1767 Set_Entity (N, Any_Type);
1768 raise Bad_Attribute;
1771 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1773 Error_Msg_Name_1 := Aname;
1774 Error_Msg_N (Msg, Error_Node);
1782 procedure Error_Attr_P (Msg : String) is
1784 Error_Msg_Name_1 := Aname;
1785 Error_Msg_F (Msg, P);
1789 ----------------------------
1790 -- Legal_Formal_Attribute --
1791 ----------------------------
1793 procedure Legal_Formal_Attribute is
1797 if not Is_Entity_Name (P)
1798 or else not Is_Type (Entity (P))
1800 Error_Attr_P ("prefix of % attribute must be generic type");
1802 elsif Is_Generic_Actual_Type (Entity (P))
1804 or else In_Inlined_Body
1808 elsif Is_Generic_Type (Entity (P)) then
1809 if not Is_Indefinite_Subtype (Entity (P)) then
1811 ("prefix of % attribute must be indefinite generic type");
1816 ("prefix of % attribute must be indefinite generic type");
1819 Set_Etype (N, Standard_Boolean);
1820 end Legal_Formal_Attribute;
1822 ------------------------
1823 -- Standard_Attribute --
1824 ------------------------
1826 procedure Standard_Attribute (Val : Int) is
1828 Check_Standard_Prefix;
1829 Rewrite (N, Make_Integer_Literal (Loc, Val));
1831 end Standard_Attribute;
1833 -------------------------
1834 -- Unexpected Argument --
1835 -------------------------
1837 procedure Unexpected_Argument (En : Node_Id) is
1839 Error_Attr ("unexpected argument for % attribute", En);
1840 end Unexpected_Argument;
1842 -------------------------------------------------
1843 -- Validate_Non_Static_Attribute_Function_Call --
1844 -------------------------------------------------
1846 -- This function should be moved to Sem_Dist ???
1848 procedure Validate_Non_Static_Attribute_Function_Call is
1850 if In_Preelaborated_Unit
1851 and then not In_Subprogram_Or_Concurrent_Unit
1853 Flag_Non_Static_Expr
1854 ("non-static function call in preelaborated unit!", N);
1856 end Validate_Non_Static_Attribute_Function_Call;
1858 -----------------------------------------------
1859 -- Start of Processing for Analyze_Attribute --
1860 -----------------------------------------------
1863 -- Immediate return if unrecognized attribute (already diagnosed
1864 -- by parser, so there is nothing more that we need to do)
1866 if not Is_Attribute_Name (Aname) then
1867 raise Bad_Attribute;
1870 -- Deal with Ada 83 issues
1872 if Comes_From_Source (N) then
1873 if not Attribute_83 (Attr_Id) then
1874 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1875 Error_Msg_Name_1 := Aname;
1876 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1879 if Attribute_Impl_Def (Attr_Id) then
1880 Check_Restriction (No_Implementation_Attributes, N);
1885 -- Deal with Ada 2005 issues
1887 if Attribute_05 (Attr_Id) and then Ada_Version <= Ada_95 then
1888 Check_Restriction (No_Implementation_Attributes, N);
1891 -- Remote access to subprogram type access attribute reference needs
1892 -- unanalyzed copy for tree transformation. The analyzed copy is used
1893 -- for its semantic information (whether prefix is a remote subprogram
1894 -- name), the unanalyzed copy is used to construct new subtree rooted
1895 -- with N_Aggregate which represents a fat pointer aggregate.
1897 if Aname = Name_Access then
1898 Discard_Node (Copy_Separate_Tree (N));
1901 -- Analyze prefix and exit if error in analysis. If the prefix is an
1902 -- incomplete type, use full view if available. Note that there are
1903 -- some attributes for which we do not analyze the prefix, since the
1904 -- prefix is not a normal name.
1906 if Aname /= Name_Elab_Body
1908 Aname /= Name_Elab_Spec
1910 Aname /= Name_UET_Address
1912 Aname /= Name_Enabled
1915 P_Type := Etype (P);
1917 if Is_Entity_Name (P)
1918 and then Present (Entity (P))
1919 and then Is_Type (Entity (P))
1921 if Ekind (Entity (P)) = E_Incomplete_Type then
1922 P_Type := Get_Full_View (P_Type);
1923 Set_Entity (P, P_Type);
1924 Set_Etype (P, P_Type);
1926 elsif Entity (P) = Current_Scope
1927 and then Is_Record_Type (Entity (P))
1929 -- Use of current instance within the type. Verify that if the
1930 -- attribute appears within a constraint, it yields an access
1931 -- type, other uses are illegal.
1939 and then Nkind (Parent (Par)) /= N_Component_Definition
1941 Par := Parent (Par);
1945 and then Nkind (Par) = N_Subtype_Indication
1947 if Attr_Id /= Attribute_Access
1948 and then Attr_Id /= Attribute_Unchecked_Access
1949 and then Attr_Id /= Attribute_Unrestricted_Access
1952 ("in a constraint the current instance can only"
1953 & " be used with an access attribute", N);
1960 if P_Type = Any_Type then
1961 raise Bad_Attribute;
1964 P_Base_Type := Base_Type (P_Type);
1967 -- Analyze expressions that may be present, exiting if an error occurs
1974 E1 := First (Exprs);
1977 -- Check for missing/bad expression (result of previous error)
1979 if No (E1) or else Etype (E1) = Any_Type then
1980 raise Bad_Attribute;
1985 if Present (E2) then
1988 if Etype (E2) = Any_Type then
1989 raise Bad_Attribute;
1992 if Present (Next (E2)) then
1993 Unexpected_Argument (Next (E2));
1998 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
1999 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
2001 if Ada_Version < Ada_2005
2002 and then Is_Overloaded (P)
2003 and then Aname /= Name_Access
2004 and then Aname /= Name_Address
2005 and then Aname /= Name_Code_Address
2006 and then Aname /= Name_Count
2007 and then Aname /= Name_Result
2008 and then Aname /= Name_Unchecked_Access
2010 Error_Attr ("ambiguous prefix for % attribute", P);
2012 elsif Ada_Version >= Ada_2005
2013 and then Is_Overloaded (P)
2014 and then Aname /= Name_Access
2015 and then Aname /= Name_Address
2016 and then Aname /= Name_Code_Address
2017 and then Aname /= Name_Result
2018 and then Aname /= Name_Unchecked_Access
2020 -- Ada 2005 (AI-345): Since protected and task types have primitive
2021 -- entry wrappers, the attributes Count, Caller and AST_Entry require
2024 if Ada_Version >= Ada_2005
2025 and then (Aname = Name_Count
2026 or else Aname = Name_Caller
2027 or else Aname = Name_AST_Entry)
2030 Count : Natural := 0;
2035 Get_First_Interp (P, I, It);
2036 while Present (It.Nam) loop
2037 if Comes_From_Source (It.Nam) then
2043 Get_Next_Interp (I, It);
2047 Error_Attr ("ambiguous prefix for % attribute", P);
2049 Set_Is_Overloaded (P, False);
2054 Error_Attr ("ambiguous prefix for % attribute", P);
2058 -- Remaining processing depends on attribute
2066 when Attribute_Abort_Signal =>
2067 Check_Standard_Prefix;
2069 New_Reference_To (Stand.Abort_Signal, Loc));
2076 when Attribute_Access =>
2077 Analyze_Access_Attribute;
2083 when Attribute_Address =>
2086 -- Check for some junk cases, where we have to allow the address
2087 -- attribute but it does not make much sense, so at least for now
2088 -- just replace with Null_Address.
2090 -- We also do this if the prefix is a reference to the AST_Entry
2091 -- attribute. If expansion is active, the attribute will be
2092 -- replaced by a function call, and address will work fine and
2093 -- get the proper value, but if expansion is not active, then
2094 -- the check here allows proper semantic analysis of the reference.
2096 -- An Address attribute created by expansion is legal even when it
2097 -- applies to other entity-denoting expressions.
2099 if Is_Protected_Self_Reference (P) then
2101 -- Address attribute on a protected object self reference is legal
2105 elsif Is_Entity_Name (P) then
2107 Ent : constant Entity_Id := Entity (P);
2110 if Is_Subprogram (Ent) then
2111 Set_Address_Taken (Ent);
2112 Kill_Current_Values (Ent);
2114 -- An Address attribute is accepted when generated by the
2115 -- compiler for dispatching operation, and an error is
2116 -- issued once the subprogram is frozen (to avoid confusing
2117 -- errors about implicit uses of Address in the dispatch
2118 -- table initialization).
2120 if Has_Pragma_Inline_Always (Entity (P))
2121 and then Comes_From_Source (P)
2124 ("prefix of % attribute cannot be Inline_Always" &
2127 -- It is illegal to apply 'Address to an intrinsic
2128 -- subprogram. This is now formalized in AI05-0095.
2129 -- In an instance, an attempt to obtain 'Address of an
2130 -- intrinsic subprogram (e.g the renaming of a predefined
2131 -- operator that is an actual) raises Program_Error.
2133 elsif Convention (Ent) = Convention_Intrinsic then
2136 Make_Raise_Program_Error (Loc,
2137 Reason => PE_Address_Of_Intrinsic));
2141 ("cannot take Address of intrinsic subprogram", N);
2144 -- Issue an error if prefix denotes an eliminated subprogram
2147 Check_For_Eliminated_Subprogram (P, Ent);
2150 elsif Is_Object (Ent)
2151 or else Ekind (Ent) = E_Label
2153 Set_Address_Taken (Ent);
2155 -- If we have an address of an object, and the attribute
2156 -- comes from source, then set the object as potentially
2157 -- source modified. We do this because the resulting address
2158 -- can potentially be used to modify the variable and we
2159 -- might not detect this, leading to some junk warnings.
2161 Set_Never_Set_In_Source (Ent, False);
2163 elsif (Is_Concurrent_Type (Etype (Ent))
2164 and then Etype (Ent) = Base_Type (Ent))
2165 or else Ekind (Ent) = E_Package
2166 or else Is_Generic_Unit (Ent)
2169 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2172 Error_Attr ("invalid prefix for % attribute", P);
2176 elsif Nkind (P) = N_Attribute_Reference
2177 and then Attribute_Name (P) = Name_AST_Entry
2180 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2182 elsif Is_Object_Reference (P) then
2185 elsif Nkind (P) = N_Selected_Component
2186 and then Is_Subprogram (Entity (Selector_Name (P)))
2190 -- What exactly are we allowing here ??? and is this properly
2191 -- documented in the sinfo documentation for this node ???
2193 elsif not Comes_From_Source (N) then
2197 Error_Attr ("invalid prefix for % attribute", P);
2200 Set_Etype (N, RTE (RE_Address));
2206 when Attribute_Address_Size =>
2207 Standard_Attribute (System_Address_Size);
2213 when Attribute_Adjacent =>
2214 Check_Floating_Point_Type_2;
2215 Set_Etype (N, P_Base_Type);
2216 Resolve (E1, P_Base_Type);
2217 Resolve (E2, P_Base_Type);
2223 when Attribute_Aft =>
2224 Check_Fixed_Point_Type_0;
2225 Set_Etype (N, Universal_Integer);
2231 when Attribute_Alignment =>
2233 -- Don't we need more checking here, cf Size ???
2236 Check_Not_Incomplete_Type;
2238 Set_Etype (N, Universal_Integer);
2244 when Attribute_Asm_Input =>
2245 Check_Asm_Attribute;
2247 -- The back-end may need to take the address of E2
2249 if Is_Entity_Name (E2) then
2250 Set_Address_Taken (Entity (E2));
2253 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2259 when Attribute_Asm_Output =>
2260 Check_Asm_Attribute;
2262 if Etype (E2) = Any_Type then
2265 elsif Aname = Name_Asm_Output then
2266 if not Is_Variable (E2) then
2268 ("second argument for Asm_Output is not variable", E2);
2272 Note_Possible_Modification (E2, Sure => True);
2274 -- The back-end may need to take the address of E2
2276 if Is_Entity_Name (E2) then
2277 Set_Address_Taken (Entity (E2));
2280 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2286 when Attribute_AST_Entry => AST_Entry : declare
2292 -- Indicates if entry family index is present. Note the coding
2293 -- here handles the entry family case, but in fact it cannot be
2294 -- executed currently, because pragma AST_Entry does not permit
2295 -- the specification of an entry family.
2297 procedure Bad_AST_Entry;
2298 -- Signal a bad AST_Entry pragma
2300 function OK_Entry (E : Entity_Id) return Boolean;
2301 -- Checks that E is of an appropriate entity kind for an entry
2302 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2303 -- is set True for the entry family case). In the True case,
2304 -- makes sure that Is_AST_Entry is set on the entry.
2310 procedure Bad_AST_Entry is
2312 Error_Attr_P ("prefix for % attribute must be task entry");
2319 function OK_Entry (E : Entity_Id) return Boolean is
2324 Result := (Ekind (E) = E_Entry_Family);
2326 Result := (Ekind (E) = E_Entry);
2330 if not Is_AST_Entry (E) then
2331 Error_Msg_Name_2 := Aname;
2332 Error_Attr ("% attribute requires previous % pragma", P);
2339 -- Start of processing for AST_Entry
2345 -- Deal with entry family case
2347 if Nkind (P) = N_Indexed_Component then
2355 Ptyp := Etype (Pref);
2357 if Ptyp = Any_Type or else Error_Posted (Pref) then
2361 -- If the prefix is a selected component whose prefix is of an
2362 -- access type, then introduce an explicit dereference.
2363 -- ??? Could we reuse Check_Dereference here?
2365 if Nkind (Pref) = N_Selected_Component
2366 and then Is_Access_Type (Ptyp)
2369 Make_Explicit_Dereference (Sloc (Pref),
2370 Relocate_Node (Pref)));
2371 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2374 -- Prefix can be of the form a.b, where a is a task object
2375 -- and b is one of the entries of the corresponding task type.
2377 if Nkind (Pref) = N_Selected_Component
2378 and then OK_Entry (Entity (Selector_Name (Pref)))
2379 and then Is_Object_Reference (Prefix (Pref))
2380 and then Is_Task_Type (Etype (Prefix (Pref)))
2384 -- Otherwise the prefix must be an entry of a containing task,
2385 -- or of a variable of the enclosing task type.
2388 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2389 Ent := Entity (Pref);
2391 if not OK_Entry (Ent)
2392 or else not In_Open_Scopes (Scope (Ent))
2402 Set_Etype (N, RTE (RE_AST_Handler));
2409 -- Note: when the base attribute appears in the context of a subtype
2410 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2411 -- the following circuit.
2413 when Attribute_Base => Base : declare
2421 if Ada_Version >= Ada_95
2422 and then not Is_Scalar_Type (Typ)
2423 and then not Is_Generic_Type (Typ)
2425 Error_Attr_P ("prefix of Base attribute must be scalar type");
2427 elsif Sloc (Typ) = Standard_Location
2428 and then Base_Type (Typ) = Typ
2429 and then Warn_On_Redundant_Constructs
2431 Error_Msg_NE -- CODEFIX
2432 ("?redundant attribute, & is its own base type", N, Typ);
2435 Set_Etype (N, Base_Type (Entity (P)));
2436 Set_Entity (N, Base_Type (Entity (P)));
2437 Rewrite (N, New_Reference_To (Entity (N), Loc));
2445 when Attribute_Bit => Bit :
2449 if not Is_Object_Reference (P) then
2450 Error_Attr_P ("prefix for % attribute must be object");
2452 -- What about the access object cases ???
2458 Set_Etype (N, Universal_Integer);
2465 when Attribute_Bit_Order => Bit_Order :
2470 if not Is_Record_Type (P_Type) then
2471 Error_Attr_P ("prefix of % attribute must be record type");
2474 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2476 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2479 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2482 Set_Etype (N, RTE (RE_Bit_Order));
2485 -- Reset incorrect indication of staticness
2487 Set_Is_Static_Expression (N, False);
2494 -- Note: in generated code, we can have a Bit_Position attribute
2495 -- applied to a (naked) record component (i.e. the prefix is an
2496 -- identifier that references an E_Component or E_Discriminant
2497 -- entity directly, and this is interpreted as expected by Gigi.
2498 -- The following code will not tolerate such usage, but when the
2499 -- expander creates this special case, it marks it as analyzed
2500 -- immediately and sets an appropriate type.
2502 when Attribute_Bit_Position =>
2503 if Comes_From_Source (N) then
2507 Set_Etype (N, Universal_Integer);
2513 when Attribute_Body_Version =>
2516 Set_Etype (N, RTE (RE_Version_String));
2522 when Attribute_Callable =>
2524 Set_Etype (N, Standard_Boolean);
2531 when Attribute_Caller => Caller : declare
2538 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2541 if not Is_Entry (Ent) then
2542 Error_Attr ("invalid entry name", N);
2546 Error_Attr ("invalid entry name", N);
2550 for J in reverse 0 .. Scope_Stack.Last loop
2551 S := Scope_Stack.Table (J).Entity;
2553 if S = Scope (Ent) then
2554 Error_Attr ("Caller must appear in matching accept or body", N);
2560 Set_Etype (N, RTE (RO_AT_Task_Id));
2567 when Attribute_Ceiling =>
2568 Check_Floating_Point_Type_1;
2569 Set_Etype (N, P_Base_Type);
2570 Resolve (E1, P_Base_Type);
2576 when Attribute_Class =>
2577 Check_Restriction (No_Dispatch, N);
2581 -- Applying Class to untagged incomplete type is obsolescent in Ada
2582 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
2583 -- this flag gets set by Find_Type in this situation.
2585 if Restriction_Check_Required (No_Obsolescent_Features)
2586 and then Ada_Version >= Ada_2005
2587 and then Ekind (P_Type) = E_Incomplete_Type
2590 DN : constant Node_Id := Declaration_Node (P_Type);
2592 if Nkind (DN) = N_Incomplete_Type_Declaration
2593 and then not Tagged_Present (DN)
2595 Check_Restriction (No_Obsolescent_Features, P);
2604 when Attribute_Code_Address =>
2607 if Nkind (P) = N_Attribute_Reference
2608 and then (Attribute_Name (P) = Name_Elab_Body
2610 Attribute_Name (P) = Name_Elab_Spec)
2614 elsif not Is_Entity_Name (P)
2615 or else (Ekind (Entity (P)) /= E_Function
2617 Ekind (Entity (P)) /= E_Procedure)
2619 Error_Attr ("invalid prefix for % attribute", P);
2620 Set_Address_Taken (Entity (P));
2622 -- Issue an error if the prefix denotes an eliminated subprogram
2625 Check_For_Eliminated_Subprogram (P, Entity (P));
2628 Set_Etype (N, RTE (RE_Address));
2630 ----------------------
2631 -- Compiler_Version --
2632 ----------------------
2634 when Attribute_Compiler_Version =>
2636 Check_Standard_Prefix;
2637 Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
2638 Analyze_And_Resolve (N, Standard_String);
2640 --------------------
2641 -- Component_Size --
2642 --------------------
2644 when Attribute_Component_Size =>
2646 Set_Etype (N, Universal_Integer);
2648 -- Note: unlike other array attributes, unconstrained arrays are OK
2650 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2660 when Attribute_Compose =>
2661 Check_Floating_Point_Type_2;
2662 Set_Etype (N, P_Base_Type);
2663 Resolve (E1, P_Base_Type);
2664 Resolve (E2, Any_Integer);
2670 when Attribute_Constrained =>
2672 Set_Etype (N, Standard_Boolean);
2674 -- Case from RM J.4(2) of constrained applied to private type
2676 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2677 Check_Restriction (No_Obsolescent_Features, P);
2679 if Warn_On_Obsolescent_Feature then
2681 ("constrained for private type is an " &
2682 "obsolescent feature (RM J.4)?", N);
2685 -- If we are within an instance, the attribute must be legal
2686 -- because it was valid in the generic unit. Ditto if this is
2687 -- an inlining of a function declared in an instance.
2690 or else In_Inlined_Body
2694 -- For sure OK if we have a real private type itself, but must
2695 -- be completed, cannot apply Constrained to incomplete type.
2697 elsif Is_Private_Type (Entity (P)) then
2699 -- Note: this is one of the Annex J features that does not
2700 -- generate a warning from -gnatwj, since in fact it seems
2701 -- very useful, and is used in the GNAT runtime.
2703 Check_Not_Incomplete_Type;
2707 -- Normal (non-obsolescent case) of application to object of
2708 -- a discriminated type.
2711 Check_Object_Reference (P);
2713 -- If N does not come from source, then we allow the
2714 -- the attribute prefix to be of a private type whose
2715 -- full type has discriminants. This occurs in cases
2716 -- involving expanded calls to stream attributes.
2718 if not Comes_From_Source (N) then
2719 P_Type := Underlying_Type (P_Type);
2722 -- Must have discriminants or be an access type designating
2723 -- a type with discriminants. If it is a classwide type is ???
2724 -- has unknown discriminants.
2726 if Has_Discriminants (P_Type)
2727 or else Has_Unknown_Discriminants (P_Type)
2729 (Is_Access_Type (P_Type)
2730 and then Has_Discriminants (Designated_Type (P_Type)))
2734 -- Also allow an object of a generic type if extensions allowed
2735 -- and allow this for any type at all.
2737 elsif (Is_Generic_Type (P_Type)
2738 or else Is_Generic_Actual_Type (P_Type))
2739 and then Extensions_Allowed
2745 -- Fall through if bad prefix
2748 ("prefix of % attribute must be object of discriminated type");
2754 when Attribute_Copy_Sign =>
2755 Check_Floating_Point_Type_2;
2756 Set_Etype (N, P_Base_Type);
2757 Resolve (E1, P_Base_Type);
2758 Resolve (E2, P_Base_Type);
2764 when Attribute_Count => Count :
2773 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2776 if Ekind (Ent) /= E_Entry then
2777 Error_Attr ("invalid entry name", N);
2780 elsif Nkind (P) = N_Indexed_Component then
2781 if not Is_Entity_Name (Prefix (P))
2782 or else No (Entity (Prefix (P)))
2783 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2785 if Nkind (Prefix (P)) = N_Selected_Component
2786 and then Present (Entity (Selector_Name (Prefix (P))))
2787 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2791 ("attribute % must apply to entry of current task", P);
2794 Error_Attr ("invalid entry family name", P);
2799 Ent := Entity (Prefix (P));
2802 elsif Nkind (P) = N_Selected_Component
2803 and then Present (Entity (Selector_Name (P)))
2804 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2807 ("attribute % must apply to entry of current task", P);
2810 Error_Attr ("invalid entry name", N);
2814 for J in reverse 0 .. Scope_Stack.Last loop
2815 S := Scope_Stack.Table (J).Entity;
2817 if S = Scope (Ent) then
2818 if Nkind (P) = N_Expanded_Name then
2819 Tsk := Entity (Prefix (P));
2821 -- The prefix denotes either the task type, or else a
2822 -- single task whose task type is being analyzed.
2827 or else (not Is_Type (Tsk)
2828 and then Etype (Tsk) = S
2829 and then not (Comes_From_Source (S)))
2834 ("Attribute % must apply to entry of current task", N);
2840 elsif Ekind (Scope (Ent)) in Task_Kind
2842 not Ekind_In (S, E_Loop, E_Block, E_Entry, E_Entry_Family)
2844 Error_Attr ("Attribute % cannot appear in inner unit", N);
2846 elsif Ekind (Scope (Ent)) = E_Protected_Type
2847 and then not Has_Completion (Scope (Ent))
2849 Error_Attr ("attribute % can only be used inside body", N);
2853 if Is_Overloaded (P) then
2855 Index : Interp_Index;
2859 Get_First_Interp (P, Index, It);
2861 while Present (It.Nam) loop
2862 if It.Nam = Ent then
2865 -- Ada 2005 (AI-345): Do not consider primitive entry
2866 -- wrappers generated for task or protected types.
2868 elsif Ada_Version >= Ada_2005
2869 and then not Comes_From_Source (It.Nam)
2874 Error_Attr ("ambiguous entry name", N);
2877 Get_Next_Interp (Index, It);
2882 Set_Etype (N, Universal_Integer);
2885 -----------------------
2886 -- Default_Bit_Order --
2887 -----------------------
2889 when Attribute_Default_Bit_Order => Default_Bit_Order :
2891 Check_Standard_Prefix;
2893 if Bytes_Big_Endian then
2895 Make_Integer_Literal (Loc, False_Value));
2898 Make_Integer_Literal (Loc, True_Value));
2901 Set_Etype (N, Universal_Integer);
2902 Set_Is_Static_Expression (N);
2903 end Default_Bit_Order;
2909 when Attribute_Definite =>
2910 Legal_Formal_Attribute;
2916 when Attribute_Delta =>
2917 Check_Fixed_Point_Type_0;
2918 Set_Etype (N, Universal_Real);
2924 when Attribute_Denorm =>
2925 Check_Floating_Point_Type_0;
2926 Set_Etype (N, Standard_Boolean);
2932 when Attribute_Digits =>
2936 if not Is_Floating_Point_Type (P_Type)
2937 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2940 ("prefix of % attribute must be float or decimal type");
2943 Set_Etype (N, Universal_Integer);
2949 -- Also handles processing for Elab_Spec
2951 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2953 Check_Unit_Name (P);
2954 Set_Etype (N, Standard_Void_Type);
2956 -- We have to manually call the expander in this case to get
2957 -- the necessary expansion (normally attributes that return
2958 -- entities are not expanded).
2966 -- Shares processing with Elab_Body
2972 when Attribute_Elaborated =>
2975 Set_Etype (N, Standard_Boolean);
2981 when Attribute_Emax =>
2982 Check_Floating_Point_Type_0;
2983 Set_Etype (N, Universal_Integer);
2989 when Attribute_Enabled =>
2990 Check_Either_E0_Or_E1;
2992 if Present (E1) then
2993 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
2994 Error_Msg_N ("entity name expected for Enabled attribute", E1);
2999 if Nkind (P) /= N_Identifier then
3000 Error_Msg_N ("identifier expected (check name)", P);
3001 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
3002 Error_Msg_N ("& is not a recognized check name", P);
3005 Set_Etype (N, Standard_Boolean);
3011 when Attribute_Enum_Rep => Enum_Rep : declare
3013 if Present (E1) then
3015 Check_Discrete_Type;
3016 Resolve (E1, P_Base_Type);
3019 if not Is_Entity_Name (P)
3020 or else (not Is_Object (Entity (P))
3022 Ekind (Entity (P)) /= E_Enumeration_Literal)
3025 ("prefix of % attribute must be " &
3026 "discrete type/object or enum literal");
3030 Set_Etype (N, Universal_Integer);
3037 when Attribute_Enum_Val => Enum_Val : begin
3041 if not Is_Enumeration_Type (P_Type) then
3042 Error_Attr_P ("prefix of % attribute must be enumeration type");
3045 -- If the enumeration type has a standard representation, the effect
3046 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3048 if not Has_Non_Standard_Rep (P_Base_Type) then
3050 Make_Attribute_Reference (Loc,
3051 Prefix => Relocate_Node (Prefix (N)),
3052 Attribute_Name => Name_Val,
3053 Expressions => New_List (Relocate_Node (E1))));
3054 Analyze_And_Resolve (N, P_Base_Type);
3056 -- Non-standard representation case (enumeration with holes)
3060 Resolve (E1, Any_Integer);
3061 Set_Etype (N, P_Base_Type);
3069 when Attribute_Epsilon =>
3070 Check_Floating_Point_Type_0;
3071 Set_Etype (N, Universal_Real);
3077 when Attribute_Exponent =>
3078 Check_Floating_Point_Type_1;
3079 Set_Etype (N, Universal_Integer);
3080 Resolve (E1, P_Base_Type);
3086 when Attribute_External_Tag =>
3090 Set_Etype (N, Standard_String);
3092 if not Is_Tagged_Type (P_Type) then
3093 Error_Attr_P ("prefix of % attribute must be tagged");
3100 when Attribute_Fast_Math =>
3101 Check_Standard_Prefix;
3103 if Opt.Fast_Math then
3104 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
3106 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
3113 when Attribute_First =>
3114 Check_Array_Or_Scalar_Type;
3115 Bad_Attribute_For_Predicate;
3121 when Attribute_First_Bit =>
3123 Set_Etype (N, Universal_Integer);
3129 when Attribute_Fixed_Value =>
3131 Check_Fixed_Point_Type;
3132 Resolve (E1, Any_Integer);
3133 Set_Etype (N, P_Base_Type);
3139 when Attribute_Floor =>
3140 Check_Floating_Point_Type_1;
3141 Set_Etype (N, P_Base_Type);
3142 Resolve (E1, P_Base_Type);
3148 when Attribute_Fore =>
3149 Check_Fixed_Point_Type_0;
3150 Set_Etype (N, Universal_Integer);
3156 when Attribute_Fraction =>
3157 Check_Floating_Point_Type_1;
3158 Set_Etype (N, P_Base_Type);
3159 Resolve (E1, P_Base_Type);
3165 when Attribute_From_Any =>
3167 Check_PolyORB_Attribute;
3168 Set_Etype (N, P_Base_Type);
3170 -----------------------
3171 -- Has_Access_Values --
3172 -----------------------
3174 when Attribute_Has_Access_Values =>
3177 Set_Etype (N, Standard_Boolean);
3179 -----------------------
3180 -- Has_Tagged_Values --
3181 -----------------------
3183 when Attribute_Has_Tagged_Values =>
3186 Set_Etype (N, Standard_Boolean);
3188 -----------------------
3189 -- Has_Discriminants --
3190 -----------------------
3192 when Attribute_Has_Discriminants =>
3193 Legal_Formal_Attribute;
3199 when Attribute_Identity =>
3203 if Etype (P) = Standard_Exception_Type then
3204 Set_Etype (N, RTE (RE_Exception_Id));
3206 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3207 -- task interface class-wide types.
3209 elsif Is_Task_Type (Etype (P))
3210 or else (Is_Access_Type (Etype (P))
3211 and then Is_Task_Type (Designated_Type (Etype (P))))
3212 or else (Ada_Version >= Ada_2005
3213 and then Ekind (Etype (P)) = E_Class_Wide_Type
3214 and then Is_Interface (Etype (P))
3215 and then Is_Task_Interface (Etype (P)))
3218 Set_Etype (N, RTE (RO_AT_Task_Id));
3221 if Ada_Version >= Ada_2005 then
3223 ("prefix of % attribute must be an exception, a " &
3224 "task or a task interface class-wide object");
3227 ("prefix of % attribute must be a task or an exception");
3235 when Attribute_Image => Image :
3237 Set_Etype (N, Standard_String);
3240 if Is_Real_Type (P_Type) then
3241 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3242 Error_Msg_Name_1 := Aname;
3244 ("(Ada 83) % attribute not allowed for real types", N);
3248 if Is_Enumeration_Type (P_Type) then
3249 Check_Restriction (No_Enumeration_Maps, N);
3253 Resolve (E1, P_Base_Type);
3255 Validate_Non_Static_Attribute_Function_Call;
3262 when Attribute_Img => Img :
3265 Set_Etype (N, Standard_String);
3267 if not Is_Scalar_Type (P_Type)
3268 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3271 ("prefix of % attribute must be scalar object name");
3281 when Attribute_Input =>
3283 Check_Stream_Attribute (TSS_Stream_Input);
3284 Set_Etype (N, P_Base_Type);
3290 when Attribute_Integer_Value =>
3293 Resolve (E1, Any_Fixed);
3295 -- Signal an error if argument type is not a specific fixed-point
3296 -- subtype. An error has been signalled already if the argument
3297 -- was not of a fixed-point type.
3299 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3300 Error_Attr ("argument of % must be of a fixed-point type", E1);
3303 Set_Etype (N, P_Base_Type);
3309 when Attribute_Invalid_Value =>
3312 Set_Etype (N, P_Base_Type);
3313 Invalid_Value_Used := True;
3319 when Attribute_Large =>
3322 Set_Etype (N, Universal_Real);
3328 when Attribute_Last =>
3329 Check_Array_Or_Scalar_Type;
3330 Bad_Attribute_For_Predicate;
3336 when Attribute_Last_Bit =>
3338 Set_Etype (N, Universal_Integer);
3344 when Attribute_Leading_Part =>
3345 Check_Floating_Point_Type_2;
3346 Set_Etype (N, P_Base_Type);
3347 Resolve (E1, P_Base_Type);
3348 Resolve (E2, Any_Integer);
3354 when Attribute_Length =>
3356 Set_Etype (N, Universal_Integer);
3362 when Attribute_Machine =>
3363 Check_Floating_Point_Type_1;
3364 Set_Etype (N, P_Base_Type);
3365 Resolve (E1, P_Base_Type);
3371 when Attribute_Machine_Emax =>
3372 Check_Floating_Point_Type_0;
3373 Set_Etype (N, Universal_Integer);
3379 when Attribute_Machine_Emin =>
3380 Check_Floating_Point_Type_0;
3381 Set_Etype (N, Universal_Integer);
3383 ----------------------
3384 -- Machine_Mantissa --
3385 ----------------------
3387 when Attribute_Machine_Mantissa =>
3388 Check_Floating_Point_Type_0;
3389 Set_Etype (N, Universal_Integer);
3391 -----------------------
3392 -- Machine_Overflows --
3393 -----------------------
3395 when Attribute_Machine_Overflows =>
3398 Set_Etype (N, Standard_Boolean);
3404 when Attribute_Machine_Radix =>
3407 Set_Etype (N, Universal_Integer);
3409 ----------------------
3410 -- Machine_Rounding --
3411 ----------------------
3413 when Attribute_Machine_Rounding =>
3414 Check_Floating_Point_Type_1;
3415 Set_Etype (N, P_Base_Type);
3416 Resolve (E1, P_Base_Type);
3418 --------------------
3419 -- Machine_Rounds --
3420 --------------------
3422 when Attribute_Machine_Rounds =>
3425 Set_Etype (N, Standard_Boolean);
3431 when Attribute_Machine_Size =>
3434 Check_Not_Incomplete_Type;
3435 Set_Etype (N, Universal_Integer);
3441 when Attribute_Mantissa =>
3444 Set_Etype (N, Universal_Integer);
3450 when Attribute_Max =>
3453 Resolve (E1, P_Base_Type);
3454 Resolve (E2, P_Base_Type);
3455 Set_Etype (N, P_Base_Type);
3457 ----------------------------------
3458 -- Max_Alignment_For_Allocation --
3459 -- Max_Size_In_Storage_Elements --
3460 ----------------------------------
3462 when Attribute_Max_Alignment_For_Allocation |
3463 Attribute_Max_Size_In_Storage_Elements =>
3466 Check_Not_Incomplete_Type;
3467 Set_Etype (N, Universal_Integer);
3469 -----------------------
3470 -- Maximum_Alignment --
3471 -----------------------
3473 when Attribute_Maximum_Alignment =>
3474 Standard_Attribute (Ttypes.Maximum_Alignment);
3476 --------------------
3477 -- Mechanism_Code --
3478 --------------------
3480 when Attribute_Mechanism_Code =>
3481 if not Is_Entity_Name (P)
3482 or else not Is_Subprogram (Entity (P))
3484 Error_Attr_P ("prefix of % attribute must be subprogram");
3487 Check_Either_E0_Or_E1;
3489 if Present (E1) then
3490 Resolve (E1, Any_Integer);
3491 Set_Etype (E1, Standard_Integer);
3493 if not Is_Static_Expression (E1) then
3494 Flag_Non_Static_Expr
3495 ("expression for parameter number must be static!", E1);
3498 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3499 or else UI_To_Int (Intval (E1)) < 0
3501 Error_Attr ("invalid parameter number for % attribute", E1);
3505 Set_Etype (N, Universal_Integer);
3511 when Attribute_Min =>
3514 Resolve (E1, P_Base_Type);
3515 Resolve (E2, P_Base_Type);
3516 Set_Etype (N, P_Base_Type);
3522 when Attribute_Mod =>
3524 -- Note: this attribute is only allowed in Ada 2005 mode, but
3525 -- we do not need to test that here, since Mod is only recognized
3526 -- as an attribute name in Ada 2005 mode during the parse.
3529 Check_Modular_Integer_Type;
3530 Resolve (E1, Any_Integer);
3531 Set_Etype (N, P_Base_Type);
3537 when Attribute_Model =>
3538 Check_Floating_Point_Type_1;
3539 Set_Etype (N, P_Base_Type);
3540 Resolve (E1, P_Base_Type);
3546 when Attribute_Model_Emin =>
3547 Check_Floating_Point_Type_0;
3548 Set_Etype (N, Universal_Integer);
3554 when Attribute_Model_Epsilon =>
3555 Check_Floating_Point_Type_0;
3556 Set_Etype (N, Universal_Real);
3558 --------------------
3559 -- Model_Mantissa --
3560 --------------------
3562 when Attribute_Model_Mantissa =>
3563 Check_Floating_Point_Type_0;
3564 Set_Etype (N, Universal_Integer);
3570 when Attribute_Model_Small =>
3571 Check_Floating_Point_Type_0;
3572 Set_Etype (N, Universal_Real);
3578 when Attribute_Modulus =>
3580 Check_Modular_Integer_Type;
3581 Set_Etype (N, Universal_Integer);
3583 --------------------
3584 -- Null_Parameter --
3585 --------------------
3587 when Attribute_Null_Parameter => Null_Parameter : declare
3588 Parnt : constant Node_Id := Parent (N);
3589 GParnt : constant Node_Id := Parent (Parnt);
3591 procedure Bad_Null_Parameter (Msg : String);
3592 -- Used if bad Null parameter attribute node is found. Issues
3593 -- given error message, and also sets the type to Any_Type to
3594 -- avoid blowups later on from dealing with a junk node.
3596 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3597 -- Called to check that Proc_Ent is imported subprogram
3599 ------------------------
3600 -- Bad_Null_Parameter --
3601 ------------------------
3603 procedure Bad_Null_Parameter (Msg : String) is
3605 Error_Msg_N (Msg, N);
3606 Set_Etype (N, Any_Type);
3607 end Bad_Null_Parameter;
3609 ----------------------
3610 -- Must_Be_Imported --
3611 ----------------------
3613 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3614 Pent : constant Entity_Id := Ultimate_Alias (Proc_Ent);
3617 -- Ignore check if procedure not frozen yet (we will get
3618 -- another chance when the default parameter is reanalyzed)
3620 if not Is_Frozen (Pent) then
3623 elsif not Is_Imported (Pent) then
3625 ("Null_Parameter can only be used with imported subprogram");
3630 end Must_Be_Imported;
3632 -- Start of processing for Null_Parameter
3637 Set_Etype (N, P_Type);
3639 -- Case of attribute used as default expression
3641 if Nkind (Parnt) = N_Parameter_Specification then
3642 Must_Be_Imported (Defining_Entity (GParnt));
3644 -- Case of attribute used as actual for subprogram (positional)
3646 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3648 and then Is_Entity_Name (Name (Parnt))
3650 Must_Be_Imported (Entity (Name (Parnt)));
3652 -- Case of attribute used as actual for subprogram (named)
3654 elsif Nkind (Parnt) = N_Parameter_Association
3655 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3657 and then Is_Entity_Name (Name (GParnt))
3659 Must_Be_Imported (Entity (Name (GParnt)));
3661 -- Not an allowed case
3665 ("Null_Parameter must be actual or default parameter");
3673 when Attribute_Object_Size =>
3676 Check_Not_Incomplete_Type;
3677 Set_Etype (N, Universal_Integer);
3683 when Attribute_Old =>
3685 -- The attribute reference is a primary. If expressions follow, the
3686 -- attribute reference is an indexable object, so rewrite the node
3689 if Present (E1) then
3691 Make_Indexed_Component (Loc,
3693 Make_Attribute_Reference (Loc,
3694 Prefix => Relocate_Node (Prefix (N)),
3695 Attribute_Name => Name_Old),
3696 Expressions => Expressions (N)));
3703 Set_Etype (N, P_Type);
3705 if No (Current_Subprogram) then
3706 Error_Attr ("attribute % can only appear within subprogram", N);
3709 if Is_Limited_Type (P_Type) then
3710 Error_Attr ("attribute % cannot apply to limited objects", P);
3713 if Is_Entity_Name (P)
3714 and then Is_Constant_Object (Entity (P))
3717 ("?attribute Old applied to constant has no effect", P);
3720 -- Check that the expression does not refer to local entities
3722 Check_Local : declare
3723 Subp : Entity_Id := Current_Subprogram;
3725 function Process (N : Node_Id) return Traverse_Result;
3726 -- Check that N does not contain references to local variables or
3727 -- other local entities of Subp.
3733 function Process (N : Node_Id) return Traverse_Result is
3735 if Is_Entity_Name (N)
3736 and then Present (Entity (N))
3737 and then not Is_Formal (Entity (N))
3738 and then Enclosing_Subprogram (Entity (N)) = Subp
3740 Error_Msg_Node_1 := Entity (N);
3742 ("attribute % cannot refer to local variable&", N);
3748 procedure Check_No_Local is new Traverse_Proc;
3750 -- Start of processing for Check_Local
3755 if In_Parameter_Specification (P) then
3757 -- We have additional restrictions on using 'Old in parameter
3760 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3762 -- Check that there is no reference to the enclosing
3763 -- subprogram local variables. Otherwise, we might end up
3764 -- being called from the enclosing subprogram and thus using
3765 -- 'Old on a local variable which is not defined at entry
3768 Subp := Enclosing_Subprogram (Current_Subprogram);
3772 -- We must prevent default expression of library-level
3773 -- subprogram from using 'Old, as the subprogram may be
3774 -- used in elaboration code for which there is no enclosing
3778 ("attribute % can only appear within subprogram", N);
3787 when Attribute_Output =>
3789 Check_Stream_Attribute (TSS_Stream_Output);
3790 Set_Etype (N, Standard_Void_Type);
3791 Resolve (N, Standard_Void_Type);
3797 when Attribute_Partition_ID => Partition_Id :
3801 if P_Type /= Any_Type then
3802 if not Is_Library_Level_Entity (Entity (P)) then
3804 ("prefix of % attribute must be library-level entity");
3806 -- The defining entity of prefix should not be declared inside a
3807 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3809 elsif Is_Entity_Name (P)
3810 and then Is_Pure (Entity (P))
3812 Error_Attr_P ("prefix of% attribute must not be declared pure");
3816 Set_Etype (N, Universal_Integer);
3819 -------------------------
3820 -- Passed_By_Reference --
3821 -------------------------
3823 when Attribute_Passed_By_Reference =>
3826 Set_Etype (N, Standard_Boolean);
3832 when Attribute_Pool_Address =>
3834 Set_Etype (N, RTE (RE_Address));
3840 when Attribute_Pos =>
3841 Check_Discrete_Type;
3843 Resolve (E1, P_Base_Type);
3844 Set_Etype (N, Universal_Integer);
3850 when Attribute_Position =>
3852 Set_Etype (N, Universal_Integer);
3858 when Attribute_Pred =>
3861 Resolve (E1, P_Base_Type);
3862 Set_Etype (N, P_Base_Type);
3864 -- Nothing to do for real type case
3866 if Is_Real_Type (P_Type) then
3869 -- If not modular type, test for overflow check required
3872 if not Is_Modular_Integer_Type (P_Type)
3873 and then not Range_Checks_Suppressed (P_Base_Type)
3875 Enable_Range_Check (E1);
3883 -- Ada 2005 (AI-327): Dynamic ceiling priorities
3885 when Attribute_Priority =>
3886 if Ada_Version < Ada_2005 then
3887 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
3892 -- The prefix must be a protected object (AARM D.5.2 (2/2))
3896 if Is_Protected_Type (Etype (P))
3897 or else (Is_Access_Type (Etype (P))
3898 and then Is_Protected_Type (Designated_Type (Etype (P))))
3900 Resolve (P, Etype (P));
3902 Error_Attr_P ("prefix of % attribute must be a protected object");
3905 Set_Etype (N, Standard_Integer);
3907 -- Must be called from within a protected procedure or entry of the
3908 -- protected object.
3915 while S /= Etype (P)
3916 and then S /= Standard_Standard
3921 if S = Standard_Standard then
3922 Error_Attr ("the attribute % is only allowed inside protected "
3927 Validate_Non_Static_Attribute_Function_Call;
3933 when Attribute_Range =>
3934 Check_Array_Or_Scalar_Type;
3935 Bad_Attribute_For_Predicate;
3937 if Ada_Version = Ada_83
3938 and then Is_Scalar_Type (P_Type)
3939 and then Comes_From_Source (N)
3942 ("(Ada 83) % attribute not allowed for scalar type", P);
3949 when Attribute_Result => Result : declare
3951 -- The enclosing scope, excluding loops for quantified expressions
3954 -- During analysis, CS is the postcondition subprogram and PS the
3955 -- source subprogram to which the postcondition applies. During
3956 -- pre-analysis, CS is the scope of the subprogram declaration.
3959 -- Find enclosing scopes, excluding loops
3961 CS := Current_Scope;
3962 while Ekind (CS) = E_Loop loop
3968 -- If the enclosing subprogram is always inlined, the enclosing
3969 -- postcondition will not be propagated to the expanded call.
3971 if not In_Spec_Expression
3972 and then Has_Pragma_Inline_Always (PS)
3973 and then Warn_On_Redundant_Constructs
3976 ("postconditions on inlined functions not enforced?", N);
3979 -- If we are in the scope of a function and in Spec_Expression mode,
3980 -- this is likely the prescan of the postcondition pragma, and we
3981 -- just set the proper type. If there is an error it will be caught
3982 -- when the real Analyze call is done.
3984 if Ekind (CS) = E_Function
3985 and then In_Spec_Expression
3989 if Chars (CS) /= Chars (P) then
3991 ("incorrect prefix for % attribute, expected &", P, CS);
3995 Set_Etype (N, Etype (CS));
3997 -- If several functions with that name are visible,
3998 -- the intended one is the current scope.
4000 if Is_Overloaded (P) then
4002 Set_Is_Overloaded (P, False);
4005 -- Body case, where we must be inside a generated _Postcondition
4006 -- procedure, and the prefix must be on the scope stack, or else
4007 -- the attribute use is definitely misplaced. The condition itself
4008 -- may have generated transient scopes, and is not necessarily the
4012 while Present (CS) and then CS /= Standard_Standard loop
4013 if Chars (CS) = Name_uPostconditions then
4022 if Chars (CS) = Name_uPostconditions
4023 and then Ekind (PS) = E_Function
4027 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
4028 and then Chars (P) = Chars (PS)
4032 -- Within an instance, the prefix designates the local renaming
4033 -- of the original generic.
4035 elsif Is_Entity_Name (P)
4036 and then Ekind (Entity (P)) = E_Function
4037 and then Present (Alias (Entity (P)))
4038 and then Chars (Alias (Entity (P))) = Chars (PS)
4044 ("incorrect prefix for % attribute, expected &", P, PS);
4048 Rewrite (N, Make_Identifier (Sloc (N), Name_uResult));
4049 Analyze_And_Resolve (N, Etype (PS));
4053 ("% attribute can only appear" &
4054 " in function Postcondition pragma", P);
4063 when Attribute_Range_Length =>
4065 Check_Discrete_Type;
4066 Set_Etype (N, Universal_Integer);
4072 when Attribute_Read =>
4074 Check_Stream_Attribute (TSS_Stream_Read);
4075 Set_Etype (N, Standard_Void_Type);
4076 Resolve (N, Standard_Void_Type);
4077 Note_Possible_Modification (E2, Sure => True);
4083 when Attribute_Ref =>
4087 if Nkind (P) /= N_Expanded_Name
4088 or else not Is_RTE (P_Type, RE_Address)
4090 Error_Attr_P ("prefix of % attribute must be System.Address");
4093 Analyze_And_Resolve (E1, Any_Integer);
4094 Set_Etype (N, RTE (RE_Address));
4100 when Attribute_Remainder =>
4101 Check_Floating_Point_Type_2;
4102 Set_Etype (N, P_Base_Type);
4103 Resolve (E1, P_Base_Type);
4104 Resolve (E2, P_Base_Type);
4110 when Attribute_Round =>
4112 Check_Decimal_Fixed_Point_Type;
4113 Set_Etype (N, P_Base_Type);
4115 -- Because the context is universal_real (3.5.10(12)) it is a legal
4116 -- context for a universal fixed expression. This is the only
4117 -- attribute whose functional description involves U_R.
4119 if Etype (E1) = Universal_Fixed then
4121 Conv : constant Node_Id := Make_Type_Conversion (Loc,
4122 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
4123 Expression => Relocate_Node (E1));
4131 Resolve (E1, Any_Real);
4137 when Attribute_Rounding =>
4138 Check_Floating_Point_Type_1;
4139 Set_Etype (N, P_Base_Type);
4140 Resolve (E1, P_Base_Type);
4146 when Attribute_Safe_Emax =>
4147 Check_Floating_Point_Type_0;
4148 Set_Etype (N, Universal_Integer);
4154 when Attribute_Safe_First =>
4155 Check_Floating_Point_Type_0;
4156 Set_Etype (N, Universal_Real);
4162 when Attribute_Safe_Large =>
4165 Set_Etype (N, Universal_Real);
4171 when Attribute_Safe_Last =>
4172 Check_Floating_Point_Type_0;
4173 Set_Etype (N, Universal_Real);
4179 when Attribute_Safe_Small =>
4182 Set_Etype (N, Universal_Real);
4188 when Attribute_Scale =>
4190 Check_Decimal_Fixed_Point_Type;
4191 Set_Etype (N, Universal_Integer);
4197 when Attribute_Scaling =>
4198 Check_Floating_Point_Type_2;
4199 Set_Etype (N, P_Base_Type);
4200 Resolve (E1, P_Base_Type);
4206 when Attribute_Signed_Zeros =>
4207 Check_Floating_Point_Type_0;
4208 Set_Etype (N, Standard_Boolean);
4214 when Attribute_Size | Attribute_VADS_Size => Size :
4218 -- If prefix is parameterless function call, rewrite and resolve
4221 if Is_Entity_Name (P)
4222 and then Ekind (Entity (P)) = E_Function
4226 -- Similar processing for a protected function call
4228 elsif Nkind (P) = N_Selected_Component
4229 and then Ekind (Entity (Selector_Name (P))) = E_Function
4234 if Is_Object_Reference (P) then
4235 Check_Object_Reference (P);
4237 elsif Is_Entity_Name (P)
4238 and then (Is_Type (Entity (P))
4239 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4243 elsif Nkind (P) = N_Type_Conversion
4244 and then not Comes_From_Source (P)
4249 Error_Attr_P ("invalid prefix for % attribute");
4252 Check_Not_Incomplete_Type;
4254 Set_Etype (N, Universal_Integer);
4261 when Attribute_Small =>
4264 Set_Etype (N, Universal_Real);
4270 when Attribute_Storage_Pool => Storage_Pool :
4274 if Is_Access_Type (P_Type) then
4275 if Ekind (P_Type) = E_Access_Subprogram_Type then
4277 ("cannot use % attribute for access-to-subprogram type");
4280 -- Set appropriate entity
4282 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4283 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4285 Set_Entity (N, RTE (RE_Global_Pool_Object));
4288 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4290 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4291 -- Storage_Pool since this attribute is not defined for such
4292 -- types (RM E.2.3(22)).
4294 Validate_Remote_Access_To_Class_Wide_Type (N);
4297 Error_Attr_P ("prefix of % attribute must be access type");
4305 when Attribute_Storage_Size => Storage_Size :
4309 if Is_Task_Type (P_Type) then
4310 Set_Etype (N, Universal_Integer);
4312 -- Use with tasks is an obsolescent feature
4314 Check_Restriction (No_Obsolescent_Features, P);
4316 elsif Is_Access_Type (P_Type) then
4317 if Ekind (P_Type) = E_Access_Subprogram_Type then
4319 ("cannot use % attribute for access-to-subprogram type");
4322 if Is_Entity_Name (P)
4323 and then Is_Type (Entity (P))
4326 Set_Etype (N, Universal_Integer);
4328 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4329 -- Storage_Size since this attribute is not defined for
4330 -- such types (RM E.2.3(22)).
4332 Validate_Remote_Access_To_Class_Wide_Type (N);
4334 -- The prefix is allowed to be an implicit dereference
4335 -- of an access value designating a task.
4339 Set_Etype (N, Universal_Integer);
4343 Error_Attr_P ("prefix of % attribute must be access or task type");
4351 when Attribute_Storage_Unit =>
4352 Standard_Attribute (Ttypes.System_Storage_Unit);
4358 when Attribute_Stream_Size =>
4362 if Is_Entity_Name (P)
4363 and then Is_Elementary_Type (Entity (P))
4365 Set_Etype (N, Universal_Integer);
4367 Error_Attr_P ("invalid prefix for % attribute");
4374 when Attribute_Stub_Type =>
4378 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4380 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4383 ("prefix of% attribute must be remote access to classwide");
4390 when Attribute_Succ =>
4393 Resolve (E1, P_Base_Type);
4394 Set_Etype (N, P_Base_Type);
4396 -- Nothing to do for real type case
4398 if Is_Real_Type (P_Type) then
4401 -- If not modular type, test for overflow check required
4404 if not Is_Modular_Integer_Type (P_Type)
4405 and then not Range_Checks_Suppressed (P_Base_Type)
4407 Enable_Range_Check (E1);
4415 when Attribute_Tag => Tag :
4420 if not Is_Tagged_Type (P_Type) then
4421 Error_Attr_P ("prefix of % attribute must be tagged");
4423 -- Next test does not apply to generated code
4424 -- why not, and what does the illegal reference mean???
4426 elsif Is_Object_Reference (P)
4427 and then not Is_Class_Wide_Type (P_Type)
4428 and then Comes_From_Source (N)
4431 ("% attribute can only be applied to objects " &
4432 "of class - wide type");
4435 -- The prefix cannot be an incomplete type. However, references
4436 -- to 'Tag can be generated when expanding interface conversions,
4437 -- and this is legal.
4439 if Comes_From_Source (N) then
4440 Check_Not_Incomplete_Type;
4443 -- Set appropriate type
4445 Set_Etype (N, RTE (RE_Tag));
4452 when Attribute_Target_Name => Target_Name : declare
4453 TN : constant String := Sdefault.Target_Name.all;
4457 Check_Standard_Prefix;
4461 if TN (TL) = '/' or else TN (TL) = '\' then
4466 Make_String_Literal (Loc,
4467 Strval => TN (TN'First .. TL)));
4468 Analyze_And_Resolve (N, Standard_String);
4475 when Attribute_Terminated =>
4477 Set_Etype (N, Standard_Boolean);
4484 when Attribute_To_Address =>
4488 if Nkind (P) /= N_Identifier
4489 or else Chars (P) /= Name_System
4491 Error_Attr_P ("prefix of % attribute must be System");
4494 Generate_Reference (RTE (RE_Address), P);
4495 Analyze_And_Resolve (E1, Any_Integer);
4496 Set_Etype (N, RTE (RE_Address));
4502 when Attribute_To_Any =>
4504 Check_PolyORB_Attribute;
4505 Set_Etype (N, RTE (RE_Any));
4511 when Attribute_Truncation =>
4512 Check_Floating_Point_Type_1;
4513 Resolve (E1, P_Base_Type);
4514 Set_Etype (N, P_Base_Type);
4520 when Attribute_Type_Class =>
4523 Check_Not_Incomplete_Type;
4524 Set_Etype (N, RTE (RE_Type_Class));
4530 when Attribute_TypeCode =>
4532 Check_PolyORB_Attribute;
4533 Set_Etype (N, RTE (RE_TypeCode));
4539 when Attribute_Type_Key =>
4543 -- This processing belongs in Eval_Attribute ???
4546 function Type_Key return String_Id;
4547 -- A very preliminary implementation. For now, a signature
4548 -- consists of only the type name. This is clearly incomplete
4549 -- (e.g., adding a new field to a record type should change the
4550 -- type's Type_Key attribute).
4556 function Type_Key return String_Id is
4557 Full_Name : constant String_Id :=
4558 Fully_Qualified_Name_String (Entity (P));
4561 -- Copy all characters in Full_Name but the trailing NUL
4564 for J in 1 .. String_Length (Full_Name) - 1 loop
4565 Store_String_Char (Get_String_Char (Full_Name, Int (J)));
4568 Store_String_Chars ("'Type_Key");
4573 Rewrite (N, Make_String_Literal (Loc, Type_Key));
4576 Analyze_And_Resolve (N, Standard_String);
4582 when Attribute_UET_Address =>
4584 Check_Unit_Name (P);
4585 Set_Etype (N, RTE (RE_Address));
4587 -----------------------
4588 -- Unbiased_Rounding --
4589 -----------------------
4591 when Attribute_Unbiased_Rounding =>
4592 Check_Floating_Point_Type_1;
4593 Set_Etype (N, P_Base_Type);
4594 Resolve (E1, P_Base_Type);
4596 ----------------------
4597 -- Unchecked_Access --
4598 ----------------------
4600 when Attribute_Unchecked_Access =>
4601 if Comes_From_Source (N) then
4602 Check_Restriction (No_Unchecked_Access, N);
4605 Analyze_Access_Attribute;
4607 -------------------------
4608 -- Unconstrained_Array --
4609 -------------------------
4611 when Attribute_Unconstrained_Array =>
4614 Check_Not_Incomplete_Type;
4615 Set_Etype (N, Standard_Boolean);
4617 ------------------------------
4618 -- Universal_Literal_String --
4619 ------------------------------
4621 -- This is a GNAT specific attribute whose prefix must be a named
4622 -- number where the expression is either a single numeric literal,
4623 -- or a numeric literal immediately preceded by a minus sign. The
4624 -- result is equivalent to a string literal containing the text of
4625 -- the literal as it appeared in the source program with a possible
4626 -- leading minus sign.
4628 when Attribute_Universal_Literal_String => Universal_Literal_String :
4632 if not Is_Entity_Name (P)
4633 or else Ekind (Entity (P)) not in Named_Kind
4635 Error_Attr_P ("prefix for % attribute must be named number");
4642 Src : Source_Buffer_Ptr;
4645 Expr := Original_Node (Expression (Parent (Entity (P))));
4647 if Nkind (Expr) = N_Op_Minus then
4649 Expr := Original_Node (Right_Opnd (Expr));
4654 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4656 ("named number for % attribute must be simple literal", N);
4659 -- Build string literal corresponding to source literal text
4664 Store_String_Char (Get_Char_Code ('-'));
4668 Src := Source_Text (Get_Source_File_Index (S));
4670 while Src (S) /= ';' and then Src (S) /= ' ' loop
4671 Store_String_Char (Get_Char_Code (Src (S)));
4675 -- Now we rewrite the attribute with the string literal
4678 Make_String_Literal (Loc, End_String));
4682 end Universal_Literal_String;
4684 -------------------------
4685 -- Unrestricted_Access --
4686 -------------------------
4688 -- This is a GNAT specific attribute which is like Access except that
4689 -- all scope checks and checks for aliased views are omitted.
4691 when Attribute_Unrestricted_Access =>
4692 if Comes_From_Source (N) then
4693 Check_Restriction (No_Unchecked_Access, N);
4696 if Is_Entity_Name (P) then
4697 Set_Address_Taken (Entity (P));
4700 Analyze_Access_Attribute;
4706 when Attribute_Val => Val : declare
4709 Check_Discrete_Type;
4710 Resolve (E1, Any_Integer);
4711 Set_Etype (N, P_Base_Type);
4713 -- Note, we need a range check in general, but we wait for the
4714 -- Resolve call to do this, since we want to let Eval_Attribute
4715 -- have a chance to find an static illegality first!
4722 when Attribute_Valid =>
4725 -- Ignore check for object if we have a 'Valid reference generated
4726 -- by the expanded code, since in some cases valid checks can occur
4727 -- on items that are names, but are not objects (e.g. attributes).
4729 if Comes_From_Source (N) then
4730 Check_Object_Reference (P);
4733 if not Is_Scalar_Type (P_Type) then
4734 Error_Attr_P ("object for % attribute must be of scalar type");
4737 Set_Etype (N, Standard_Boolean);
4743 when Attribute_Value => Value :
4748 -- Case of enumeration type
4750 if Is_Enumeration_Type (P_Type) then
4751 Check_Restriction (No_Enumeration_Maps, N);
4753 -- Mark all enumeration literals as referenced, since the use of
4754 -- the Value attribute can implicitly reference any of the
4755 -- literals of the enumeration base type.
4758 Ent : Entity_Id := First_Literal (P_Base_Type);
4760 while Present (Ent) loop
4761 Set_Referenced (Ent);
4767 -- Set Etype before resolving expression because expansion of
4768 -- expression may require enclosing type. Note that the type
4769 -- returned by 'Value is the base type of the prefix type.
4771 Set_Etype (N, P_Base_Type);
4772 Validate_Non_Static_Attribute_Function_Call;
4779 when Attribute_Value_Size =>
4782 Check_Not_Incomplete_Type;
4783 Set_Etype (N, Universal_Integer);
4789 when Attribute_Version =>
4792 Set_Etype (N, RTE (RE_Version_String));
4798 when Attribute_Wchar_T_Size =>
4799 Standard_Attribute (Interfaces_Wchar_T_Size);
4805 when Attribute_Wide_Image => Wide_Image :
4808 Set_Etype (N, Standard_Wide_String);
4810 Resolve (E1, P_Base_Type);
4811 Validate_Non_Static_Attribute_Function_Call;
4814 ---------------------
4815 -- Wide_Wide_Image --
4816 ---------------------
4818 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
4821 Set_Etype (N, Standard_Wide_Wide_String);
4823 Resolve (E1, P_Base_Type);
4824 Validate_Non_Static_Attribute_Function_Call;
4825 end Wide_Wide_Image;
4831 when Attribute_Wide_Value => Wide_Value :
4836 -- Set Etype before resolving expression because expansion
4837 -- of expression may require enclosing type.
4839 Set_Etype (N, P_Type);
4840 Validate_Non_Static_Attribute_Function_Call;
4843 ---------------------
4844 -- Wide_Wide_Value --
4845 ---------------------
4847 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
4852 -- Set Etype before resolving expression because expansion
4853 -- of expression may require enclosing type.
4855 Set_Etype (N, P_Type);
4856 Validate_Non_Static_Attribute_Function_Call;
4857 end Wide_Wide_Value;
4859 ---------------------
4860 -- Wide_Wide_Width --
4861 ---------------------
4863 when Attribute_Wide_Wide_Width =>
4866 Set_Etype (N, Universal_Integer);
4872 when Attribute_Wide_Width =>
4875 Set_Etype (N, Universal_Integer);
4881 when Attribute_Width =>
4884 Set_Etype (N, Universal_Integer);
4890 when Attribute_Word_Size =>
4891 Standard_Attribute (System_Word_Size);
4897 when Attribute_Write =>
4899 Check_Stream_Attribute (TSS_Stream_Write);
4900 Set_Etype (N, Standard_Void_Type);
4901 Resolve (N, Standard_Void_Type);
4905 -- All errors raise Bad_Attribute, so that we get out before any further
4906 -- damage occurs when an error is detected (for example, if we check for
4907 -- one attribute expression, and the check succeeds, we want to be able
4908 -- to proceed securely assuming that an expression is in fact present.
4910 -- Note: we set the attribute analyzed in this case to prevent any
4911 -- attempt at reanalysis which could generate spurious error msgs.
4914 when Bad_Attribute =>
4916 Set_Etype (N, Any_Type);
4918 end Analyze_Attribute;
4920 --------------------
4921 -- Eval_Attribute --
4922 --------------------
4924 procedure Eval_Attribute (N : Node_Id) is
4925 Loc : constant Source_Ptr := Sloc (N);
4926 Aname : constant Name_Id := Attribute_Name (N);
4927 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
4928 P : constant Node_Id := Prefix (N);
4930 C_Type : constant Entity_Id := Etype (N);
4931 -- The type imposed by the context
4934 -- First expression, or Empty if none
4937 -- Second expression, or Empty if none
4939 P_Entity : Entity_Id;
4940 -- Entity denoted by prefix
4943 -- The type of the prefix
4945 P_Base_Type : Entity_Id;
4946 -- The base type of the prefix type
4948 P_Root_Type : Entity_Id;
4949 -- The root type of the prefix type
4952 -- True if the result is Static. This is set by the general processing
4953 -- to true if the prefix is static, and all expressions are static. It
4954 -- can be reset as processing continues for particular attributes
4956 Lo_Bound, Hi_Bound : Node_Id;
4957 -- Expressions for low and high bounds of type or array index referenced
4958 -- by First, Last, or Length attribute for array, set by Set_Bounds.
4961 -- Constraint error node used if we have an attribute reference has
4962 -- an argument that raises a constraint error. In this case we replace
4963 -- the attribute with a raise constraint_error node. This is important
4964 -- processing, since otherwise gigi might see an attribute which it is
4965 -- unprepared to deal with.
4967 procedure Check_Concurrent_Discriminant (Bound : Node_Id);
4968 -- If Bound is a reference to a discriminant of a task or protected type
4969 -- occurring within the object's body, rewrite attribute reference into
4970 -- a reference to the corresponding discriminal. Use for the expansion
4971 -- of checks against bounds of entry family index subtypes.
4973 procedure Check_Expressions;
4974 -- In case where the attribute is not foldable, the expressions, if
4975 -- any, of the attribute, are in a non-static context. This procedure
4976 -- performs the required additional checks.
4978 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
4979 -- Determines if the given type has compile time known bounds. Note
4980 -- that we enter the case statement even in cases where the prefix
4981 -- type does NOT have known bounds, so it is important to guard any
4982 -- attempt to evaluate both bounds with a call to this function.
4984 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
4985 -- This procedure is called when the attribute N has a non-static
4986 -- but compile time known value given by Val. It includes the
4987 -- necessary checks for out of range values.
4989 function Fore_Value return Nat;
4990 -- Computes the Fore value for the current attribute prefix, which is
4991 -- known to be a static fixed-point type. Used by Fore and Width.
4993 function Mantissa return Uint;
4994 -- Returns the Mantissa value for the prefix type
4996 procedure Set_Bounds;
4997 -- Used for First, Last and Length attributes applied to an array or
4998 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
4999 -- and high bound expressions for the index referenced by the attribute
5000 -- designator (i.e. the first index if no expression is present, and
5001 -- the N'th index if the value N is present as an expression). Also
5002 -- used for First and Last of scalar types. Static is reset to False
5003 -- if the type or index type is not statically constrained.
5005 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
5006 -- Verify that the prefix of a potentially static array attribute
5007 -- satisfies the conditions of 4.9 (14).
5009 -----------------------------------
5010 -- Check_Concurrent_Discriminant --
5011 -----------------------------------
5013 procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
5015 -- The concurrent (task or protected) type
5018 if Nkind (Bound) = N_Identifier
5019 and then Ekind (Entity (Bound)) = E_Discriminant
5020 and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
5022 Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
5024 if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
5026 -- Find discriminant of original concurrent type, and use
5027 -- its current discriminal, which is the renaming within
5028 -- the task/protected body.
5032 (Find_Body_Discriminal (Entity (Bound)), Loc));
5035 end Check_Concurrent_Discriminant;
5037 -----------------------
5038 -- Check_Expressions --
5039 -----------------------
5041 procedure Check_Expressions is
5045 while Present (E) loop
5046 Check_Non_Static_Context (E);
5049 end Check_Expressions;
5051 ----------------------------------
5052 -- Compile_Time_Known_Attribute --
5053 ----------------------------------
5055 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
5056 T : constant Entity_Id := Etype (N);
5059 Fold_Uint (N, Val, False);
5061 -- Check that result is in bounds of the type if it is static
5063 if Is_In_Range (N, T, Assume_Valid => False) then
5066 elsif Is_Out_Of_Range (N, T) then
5067 Apply_Compile_Time_Constraint_Error
5068 (N, "value not in range of}?", CE_Range_Check_Failed);
5070 elsif not Range_Checks_Suppressed (T) then
5071 Enable_Range_Check (N);
5074 Set_Do_Range_Check (N, False);
5076 end Compile_Time_Known_Attribute;
5078 -------------------------------
5079 -- Compile_Time_Known_Bounds --
5080 -------------------------------
5082 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
5085 Compile_Time_Known_Value (Type_Low_Bound (Typ))
5087 Compile_Time_Known_Value (Type_High_Bound (Typ));
5088 end Compile_Time_Known_Bounds;
5094 -- Note that the Fore calculation is based on the actual values
5095 -- of the bounds, and does not take into account possible rounding.
5097 function Fore_Value return Nat is
5098 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
5099 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
5100 Small : constant Ureal := Small_Value (P_Type);
5101 Lo_Real : constant Ureal := Lo * Small;
5102 Hi_Real : constant Ureal := Hi * Small;
5107 -- Bounds are given in terms of small units, so first compute
5108 -- proper values as reals.
5110 T := UR_Max (abs Lo_Real, abs Hi_Real);
5113 -- Loop to compute proper value if more than one digit required
5115 while T >= Ureal_10 loop
5127 -- Table of mantissa values accessed by function Computed using
5130 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5132 -- where D is T'Digits (RM83 3.5.7)
5134 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5176 function Mantissa return Uint is
5179 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5186 procedure Set_Bounds is
5192 -- For a string literal subtype, we have to construct the bounds.
5193 -- Valid Ada code never applies attributes to string literals, but
5194 -- it is convenient to allow the expander to generate attribute
5195 -- references of this type (e.g. First and Last applied to a string
5198 -- Note that the whole point of the E_String_Literal_Subtype is to
5199 -- avoid this construction of bounds, but the cases in which we
5200 -- have to materialize them are rare enough that we don't worry!
5202 -- The low bound is simply the low bound of the base type. The
5203 -- high bound is computed from the length of the string and this
5206 if Ekind (P_Type) = E_String_Literal_Subtype then
5207 Ityp := Etype (First_Index (Base_Type (P_Type)));
5208 Lo_Bound := Type_Low_Bound (Ityp);
5211 Make_Integer_Literal (Sloc (P),
5213 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5215 Set_Parent (Hi_Bound, P);
5216 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5219 -- For non-array case, just get bounds of scalar type
5221 elsif Is_Scalar_Type (P_Type) then
5224 -- For a fixed-point type, we must freeze to get the attributes
5225 -- of the fixed-point type set now so we can reference them.
5227 if Is_Fixed_Point_Type (P_Type)
5228 and then not Is_Frozen (Base_Type (P_Type))
5229 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5230 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5232 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5235 -- For array case, get type of proper index
5241 Ndim := UI_To_Int (Expr_Value (E1));
5244 Indx := First_Index (P_Type);
5245 for J in 1 .. Ndim - 1 loop
5249 -- If no index type, get out (some other error occurred, and
5250 -- we don't have enough information to complete the job!)
5258 Ityp := Etype (Indx);
5261 -- A discrete range in an index constraint is allowed to be a
5262 -- subtype indication. This is syntactically a pain, but should
5263 -- not propagate to the entity for the corresponding index subtype.
5264 -- After checking that the subtype indication is legal, the range
5265 -- of the subtype indication should be transfered to the entity.
5266 -- The attributes for the bounds should remain the simple retrievals
5267 -- that they are now.
5269 Lo_Bound := Type_Low_Bound (Ityp);
5270 Hi_Bound := Type_High_Bound (Ityp);
5272 if not Is_Static_Subtype (Ityp) then
5277 -------------------------------
5278 -- Statically_Denotes_Entity --
5279 -------------------------------
5281 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5285 if not Is_Entity_Name (N) then
5292 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5293 or else Statically_Denotes_Entity (Renamed_Object (E));
5294 end Statically_Denotes_Entity;
5296 -- Start of processing for Eval_Attribute
5299 -- No folding in spec expression that comes from source where the prefix
5300 -- is an unfrozen entity. This avoids premature folding in cases like:
5302 -- procedure DefExprAnal is
5303 -- type R is new Integer;
5304 -- procedure P (Arg : Integer := R'Size);
5305 -- for R'Size use 64;
5306 -- procedure P (Arg : Integer := R'Size) is
5308 -- Put_Line (Arg'Img);
5314 -- which should print 64 rather than 32. The exclusion of non-source
5315 -- constructs from this test comes from some internal usage in packed
5316 -- arrays, which otherwise fails, could use more analysis perhaps???
5318 -- We do however go ahead with generic actual types, otherwise we get
5319 -- some regressions, probably these types should be frozen anyway???
5321 if In_Spec_Expression
5322 and then Comes_From_Source (N)
5323 and then not (Is_Entity_Name (P)
5325 (Is_Frozen (Entity (P))
5326 or else (Is_Type (Entity (P))
5328 Is_Generic_Actual_Type (Entity (P)))))
5333 -- Acquire first two expressions (at the moment, no attributes take more
5334 -- than two expressions in any case).
5336 if Present (Expressions (N)) then
5337 E1 := First (Expressions (N));
5344 -- Special processing for Enabled attribute. This attribute has a very
5345 -- special prefix, and the easiest way to avoid lots of special checks
5346 -- to protect this special prefix from causing trouble is to deal with
5347 -- this attribute immediately and be done with it.
5349 if Id = Attribute_Enabled then
5351 -- We skip evaluation if the expander is not active. This is not just
5352 -- an optimization. It is of key importance that we not rewrite the
5353 -- attribute in a generic template, since we want to pick up the
5354 -- setting of the check in the instance, and testing expander active
5355 -- is as easy way of doing this as any.
5357 if Expander_Active then
5359 C : constant Check_Id := Get_Check_Id (Chars (P));
5364 if C in Predefined_Check_Id then
5365 R := Scope_Suppress (C);
5367 R := Is_Check_Suppressed (Empty, C);
5371 R := Is_Check_Suppressed (Entity (E1), C);
5375 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5377 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5385 -- Special processing for cases where the prefix is an object. For
5386 -- this purpose, a string literal counts as an object (attributes
5387 -- of string literals can only appear in generated code).
5389 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5391 -- For Component_Size, the prefix is an array object, and we apply
5392 -- the attribute to the type of the object. This is allowed for
5393 -- both unconstrained and constrained arrays, since the bounds
5394 -- have no influence on the value of this attribute.
5396 if Id = Attribute_Component_Size then
5397 P_Entity := Etype (P);
5399 -- For First and Last, the prefix is an array object, and we apply
5400 -- the attribute to the type of the array, but we need a constrained
5401 -- type for this, so we use the actual subtype if available.
5403 elsif Id = Attribute_First
5407 Id = Attribute_Length
5410 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5413 if Present (AS) and then Is_Constrained (AS) then
5416 -- If we have an unconstrained type we cannot fold
5424 -- For Size, give size of object if available, otherwise we
5425 -- cannot fold Size.
5427 elsif Id = Attribute_Size then
5428 if Is_Entity_Name (P)
5429 and then Known_Esize (Entity (P))
5431 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5439 -- For Alignment, give size of object if available, otherwise we
5440 -- cannot fold Alignment.
5442 elsif Id = Attribute_Alignment then
5443 if Is_Entity_Name (P)
5444 and then Known_Alignment (Entity (P))
5446 Fold_Uint (N, Alignment (Entity (P)), False);
5454 -- No other attributes for objects are folded
5461 -- Cases where P is not an object. Cannot do anything if P is
5462 -- not the name of an entity.
5464 elsif not Is_Entity_Name (P) then
5468 -- Otherwise get prefix entity
5471 P_Entity := Entity (P);
5474 -- At this stage P_Entity is the entity to which the attribute
5475 -- is to be applied. This is usually simply the entity of the
5476 -- prefix, except in some cases of attributes for objects, where
5477 -- as described above, we apply the attribute to the object type.
5479 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5480 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5481 -- Note we allow non-static non-generic types at this stage as further
5484 if Is_Type (P_Entity)
5485 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5486 and then (not Is_Generic_Type (P_Entity))
5490 -- Second foldable possibility is an array object (RM 4.9(8))
5492 elsif (Ekind (P_Entity) = E_Variable
5494 Ekind (P_Entity) = E_Constant)
5495 and then Is_Array_Type (Etype (P_Entity))
5496 and then (not Is_Generic_Type (Etype (P_Entity)))
5498 P_Type := Etype (P_Entity);
5500 -- If the entity is an array constant with an unconstrained nominal
5501 -- subtype then get the type from the initial value. If the value has
5502 -- been expanded into assignments, there is no expression and the
5503 -- attribute reference remains dynamic.
5505 -- We could do better here and retrieve the type ???
5507 if Ekind (P_Entity) = E_Constant
5508 and then not Is_Constrained (P_Type)
5510 if No (Constant_Value (P_Entity)) then
5513 P_Type := Etype (Constant_Value (P_Entity));
5517 -- Definite must be folded if the prefix is not a generic type,
5518 -- that is to say if we are within an instantiation. Same processing
5519 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5520 -- Has_Tagged_Value, and Unconstrained_Array.
5522 elsif (Id = Attribute_Definite
5524 Id = Attribute_Has_Access_Values
5526 Id = Attribute_Has_Discriminants
5528 Id = Attribute_Has_Tagged_Values
5530 Id = Attribute_Type_Class
5532 Id = Attribute_Unconstrained_Array
5534 Id = Attribute_Max_Alignment_For_Allocation)
5535 and then not Is_Generic_Type (P_Entity)
5539 -- We can fold 'Size applied to a type if the size is known (as happens
5540 -- for a size from an attribute definition clause). At this stage, this
5541 -- can happen only for types (e.g. record types) for which the size is
5542 -- always non-static. We exclude generic types from consideration (since
5543 -- they have bogus sizes set within templates).
5545 elsif Id = Attribute_Size
5546 and then Is_Type (P_Entity)
5547 and then (not Is_Generic_Type (P_Entity))
5548 and then Known_Static_RM_Size (P_Entity)
5550 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5553 -- We can fold 'Alignment applied to a type if the alignment is known
5554 -- (as happens for an alignment from an attribute definition clause).
5555 -- At this stage, this can happen only for types (e.g. record
5556 -- types) for which the size is always non-static. We exclude
5557 -- generic types from consideration (since they have bogus
5558 -- sizes set within templates).
5560 elsif Id = Attribute_Alignment
5561 and then Is_Type (P_Entity)
5562 and then (not Is_Generic_Type (P_Entity))
5563 and then Known_Alignment (P_Entity)
5565 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5568 -- If this is an access attribute that is known to fail accessibility
5569 -- check, rewrite accordingly.
5571 elsif Attribute_Name (N) = Name_Access
5572 and then Raises_Constraint_Error (N)
5575 Make_Raise_Program_Error (Loc,
5576 Reason => PE_Accessibility_Check_Failed));
5577 Set_Etype (N, C_Type);
5580 -- No other cases are foldable (they certainly aren't static, and at
5581 -- the moment we don't try to fold any cases other than these three).
5588 -- If either attribute or the prefix is Any_Type, then propagate
5589 -- Any_Type to the result and don't do anything else at all.
5591 if P_Type = Any_Type
5592 or else (Present (E1) and then Etype (E1) = Any_Type)
5593 or else (Present (E2) and then Etype (E2) = Any_Type)
5595 Set_Etype (N, Any_Type);
5599 -- Scalar subtype case. We have not yet enforced the static requirement
5600 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5601 -- of non-static attribute references (e.g. S'Digits for a non-static
5602 -- floating-point type, which we can compute at compile time).
5604 -- Note: this folding of non-static attributes is not simply a case of
5605 -- optimization. For many of the attributes affected, Gigi cannot handle
5606 -- the attribute and depends on the front end having folded them away.
5608 -- Note: although we don't require staticness at this stage, we do set
5609 -- the Static variable to record the staticness, for easy reference by
5610 -- those attributes where it matters (e.g. Succ and Pred), and also to
5611 -- be used to ensure that non-static folded things are not marked as
5612 -- being static (a check that is done right at the end).
5614 P_Root_Type := Root_Type (P_Type);
5615 P_Base_Type := Base_Type (P_Type);
5617 -- If the root type or base type is generic, then we cannot fold. This
5618 -- test is needed because subtypes of generic types are not always
5619 -- marked as being generic themselves (which seems odd???)
5621 if Is_Generic_Type (P_Root_Type)
5622 or else Is_Generic_Type (P_Base_Type)
5627 if Is_Scalar_Type (P_Type) then
5628 Static := Is_OK_Static_Subtype (P_Type);
5630 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5631 -- since we can't do anything with unconstrained arrays. In addition,
5632 -- only the First, Last and Length attributes are possibly static.
5634 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5635 -- Type_Class, and Unconstrained_Array are again exceptions, because
5636 -- they apply as well to unconstrained types.
5638 -- In addition Component_Size is an exception since it is possibly
5639 -- foldable, even though it is never static, and it does apply to
5640 -- unconstrained arrays. Furthermore, it is essential to fold this
5641 -- in the packed case, since otherwise the value will be incorrect.
5643 elsif Id = Attribute_Definite
5645 Id = Attribute_Has_Access_Values
5647 Id = Attribute_Has_Discriminants
5649 Id = Attribute_Has_Tagged_Values
5651 Id = Attribute_Type_Class
5653 Id = Attribute_Unconstrained_Array
5655 Id = Attribute_Component_Size
5659 elsif Id /= Attribute_Max_Alignment_For_Allocation then
5660 if not Is_Constrained (P_Type)
5661 or else (Id /= Attribute_First and then
5662 Id /= Attribute_Last and then
5663 Id /= Attribute_Length)
5669 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5670 -- scalar case, we hold off on enforcing staticness, since there are
5671 -- cases which we can fold at compile time even though they are not
5672 -- static (e.g. 'Length applied to a static index, even though other
5673 -- non-static indexes make the array type non-static). This is only
5674 -- an optimization, but it falls out essentially free, so why not.
5675 -- Again we compute the variable Static for easy reference later
5676 -- (note that no array attributes are static in Ada 83).
5678 -- We also need to set Static properly for subsequent legality checks
5679 -- which might otherwise accept non-static constants in contexts
5680 -- where they are not legal.
5682 Static := Ada_Version >= Ada_95
5683 and then Statically_Denotes_Entity (P);
5689 N := First_Index (P_Type);
5691 -- The expression is static if the array type is constrained
5692 -- by given bounds, and not by an initial expression. Constant
5693 -- strings are static in any case.
5695 if Root_Type (P_Type) /= Standard_String then
5697 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
5700 while Present (N) loop
5701 Static := Static and then Is_Static_Subtype (Etype (N));
5703 -- If however the index type is generic, or derived from
5704 -- one, attributes cannot be folded.
5706 if Is_Generic_Type (Root_Type (Etype (N)))
5707 and then Id /= Attribute_Component_Size
5717 -- Check any expressions that are present. Note that these expressions,
5718 -- depending on the particular attribute type, are either part of the
5719 -- attribute designator, or they are arguments in a case where the
5720 -- attribute reference returns a function. In the latter case, the
5721 -- rule in (RM 4.9(22)) applies and in particular requires the type
5722 -- of the expressions to be scalar in order for the attribute to be
5723 -- considered to be static.
5730 while Present (E) loop
5732 -- If expression is not static, then the attribute reference
5733 -- result certainly cannot be static.
5735 if not Is_Static_Expression (E) then
5739 -- If the result is not known at compile time, or is not of
5740 -- a scalar type, then the result is definitely not static,
5741 -- so we can quit now.
5743 if not Compile_Time_Known_Value (E)
5744 or else not Is_Scalar_Type (Etype (E))
5746 -- An odd special case, if this is a Pos attribute, this
5747 -- is where we need to apply a range check since it does
5748 -- not get done anywhere else.
5750 if Id = Attribute_Pos then
5751 if Is_Integer_Type (Etype (E)) then
5752 Apply_Range_Check (E, Etype (N));
5759 -- If the expression raises a constraint error, then so does
5760 -- the attribute reference. We keep going in this case because
5761 -- we are still interested in whether the attribute reference
5762 -- is static even if it is not static.
5764 elsif Raises_Constraint_Error (E) then
5765 Set_Raises_Constraint_Error (N);
5771 if Raises_Constraint_Error (Prefix (N)) then
5776 -- Deal with the case of a static attribute reference that raises
5777 -- constraint error. The Raises_Constraint_Error flag will already
5778 -- have been set, and the Static flag shows whether the attribute
5779 -- reference is static. In any case we certainly can't fold such an
5780 -- attribute reference.
5782 -- Note that the rewriting of the attribute node with the constraint
5783 -- error node is essential in this case, because otherwise Gigi might
5784 -- blow up on one of the attributes it never expects to see.
5786 -- The constraint_error node must have the type imposed by the context,
5787 -- to avoid spurious errors in the enclosing expression.
5789 if Raises_Constraint_Error (N) then
5791 Make_Raise_Constraint_Error (Sloc (N),
5792 Reason => CE_Range_Check_Failed);
5793 Set_Etype (CE_Node, Etype (N));
5794 Set_Raises_Constraint_Error (CE_Node);
5796 Rewrite (N, Relocate_Node (CE_Node));
5797 Set_Is_Static_Expression (N, Static);
5801 -- At this point we have a potentially foldable attribute reference.
5802 -- If Static is set, then the attribute reference definitely obeys
5803 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
5804 -- folded. If Static is not set, then the attribute may or may not
5805 -- be foldable, and the individual attribute processing routines
5806 -- test Static as required in cases where it makes a difference.
5808 -- In the case where Static is not set, we do know that all the
5809 -- expressions present are at least known at compile time (we
5810 -- assumed above that if this was not the case, then there was
5811 -- no hope of static evaluation). However, we did not require
5812 -- that the bounds of the prefix type be compile time known,
5813 -- let alone static). That's because there are many attributes
5814 -- that can be computed at compile time on non-static subtypes,
5815 -- even though such references are not static expressions.
5823 when Attribute_Adjacent =>
5826 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5832 when Attribute_Aft =>
5833 Fold_Uint (N, Aft_Value (P_Type), True);
5839 when Attribute_Alignment => Alignment_Block : declare
5840 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5843 -- Fold if alignment is set and not otherwise
5845 if Known_Alignment (P_TypeA) then
5846 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
5848 end Alignment_Block;
5854 -- Can only be folded in No_Ast_Handler case
5856 when Attribute_AST_Entry =>
5857 if not Is_AST_Entry (P_Entity) then
5859 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
5868 -- Bit can never be folded
5870 when Attribute_Bit =>
5877 -- Body_version can never be static
5879 when Attribute_Body_Version =>
5886 when Attribute_Ceiling =>
5888 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
5890 --------------------
5891 -- Component_Size --
5892 --------------------
5894 when Attribute_Component_Size =>
5895 if Known_Static_Component_Size (P_Type) then
5896 Fold_Uint (N, Component_Size (P_Type), False);
5903 when Attribute_Compose =>
5906 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
5913 -- Constrained is never folded for now, there may be cases that
5914 -- could be handled at compile time. To be looked at later.
5916 when Attribute_Constrained =>
5923 when Attribute_Copy_Sign =>
5926 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5932 when Attribute_Delta =>
5933 Fold_Ureal (N, Delta_Value (P_Type), True);
5939 when Attribute_Definite =>
5940 Rewrite (N, New_Occurrence_Of (
5941 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
5942 Analyze_And_Resolve (N, Standard_Boolean);
5948 when Attribute_Denorm =>
5950 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
5956 when Attribute_Digits =>
5957 Fold_Uint (N, Digits_Value (P_Type), True);
5963 when Attribute_Emax =>
5965 -- Ada 83 attribute is defined as (RM83 3.5.8)
5967 -- T'Emax = 4 * T'Mantissa
5969 Fold_Uint (N, 4 * Mantissa, True);
5975 when Attribute_Enum_Rep =>
5977 -- For an enumeration type with a non-standard representation use
5978 -- the Enumeration_Rep field of the proper constant. Note that this
5979 -- will not work for types Character/Wide_[Wide-]Character, since no
5980 -- real entities are created for the enumeration literals, but that
5981 -- does not matter since these two types do not have non-standard
5982 -- representations anyway.
5984 if Is_Enumeration_Type (P_Type)
5985 and then Has_Non_Standard_Rep (P_Type)
5987 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
5989 -- For enumeration types with standard representations and all
5990 -- other cases (i.e. all integer and modular types), Enum_Rep
5991 -- is equivalent to Pos.
5994 Fold_Uint (N, Expr_Value (E1), Static);
6001 when Attribute_Enum_Val => Enum_Val : declare
6005 -- We have something like Enum_Type'Enum_Val (23), so search for a
6006 -- corresponding value in the list of Enum_Rep values for the type.
6008 Lit := First_Literal (P_Base_Type);
6010 if Enumeration_Rep (Lit) = Expr_Value (E1) then
6011 Fold_Uint (N, Enumeration_Pos (Lit), Static);
6018 Apply_Compile_Time_Constraint_Error
6019 (N, "no representation value matches",
6020 CE_Range_Check_Failed,
6021 Warn => not Static);
6031 when Attribute_Epsilon =>
6033 -- Ada 83 attribute is defined as (RM83 3.5.8)
6035 -- T'Epsilon = 2.0**(1 - T'Mantissa)
6037 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
6043 when Attribute_Exponent =>
6045 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
6051 when Attribute_First => First_Attr :
6055 if Compile_Time_Known_Value (Lo_Bound) then
6056 if Is_Real_Type (P_Type) then
6057 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
6059 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
6063 Check_Concurrent_Discriminant (Lo_Bound);
6071 when Attribute_Fixed_Value =>
6078 when Attribute_Floor =>
6080 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
6086 when Attribute_Fore =>
6087 if Compile_Time_Known_Bounds (P_Type) then
6088 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
6095 when Attribute_Fraction =>
6097 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
6099 -----------------------
6100 -- Has_Access_Values --
6101 -----------------------
6103 when Attribute_Has_Access_Values =>
6104 Rewrite (N, New_Occurrence_Of
6105 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
6106 Analyze_And_Resolve (N, Standard_Boolean);
6108 -----------------------
6109 -- Has_Discriminants --
6110 -----------------------
6112 when Attribute_Has_Discriminants =>
6113 Rewrite (N, New_Occurrence_Of (
6114 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
6115 Analyze_And_Resolve (N, Standard_Boolean);
6117 -----------------------
6118 -- Has_Tagged_Values --
6119 -----------------------
6121 when Attribute_Has_Tagged_Values =>
6122 Rewrite (N, New_Occurrence_Of
6123 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
6124 Analyze_And_Resolve (N, Standard_Boolean);
6130 when Attribute_Identity =>
6137 -- Image is a scalar attribute, but is never static, because it is
6138 -- not a static function (having a non-scalar argument (RM 4.9(22))
6139 -- However, we can constant-fold the image of an enumeration literal
6140 -- if names are available.
6142 when Attribute_Image =>
6143 if Is_Entity_Name (E1)
6144 and then Ekind (Entity (E1)) = E_Enumeration_Literal
6145 and then not Discard_Names (First_Subtype (Etype (E1)))
6146 and then not Global_Discard_Names
6149 Lit : constant Entity_Id := Entity (E1);
6153 Get_Unqualified_Decoded_Name_String (Chars (Lit));
6154 Set_Casing (All_Upper_Case);
6155 Store_String_Chars (Name_Buffer (1 .. Name_Len));
6157 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
6158 Analyze_And_Resolve (N, Standard_String);
6159 Set_Is_Static_Expression (N, False);
6167 -- Img is a scalar attribute, but is never static, because it is
6168 -- not a static function (having a non-scalar argument (RM 4.9(22))
6170 when Attribute_Img =>
6177 -- We never try to fold Integer_Value (though perhaps we could???)
6179 when Attribute_Integer_Value =>
6186 -- Invalid_Value is a scalar attribute that is never static, because
6187 -- the value is by design out of range.
6189 when Attribute_Invalid_Value =>
6196 when Attribute_Large =>
6198 -- For fixed-point, we use the identity:
6200 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6202 if Is_Fixed_Point_Type (P_Type) then
6204 Make_Op_Multiply (Loc,
6206 Make_Op_Subtract (Loc,
6210 Make_Real_Literal (Loc, Ureal_2),
6212 Make_Attribute_Reference (Loc,
6214 Attribute_Name => Name_Mantissa)),
6215 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6218 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6220 Analyze_And_Resolve (N, C_Type);
6222 -- Floating-point (Ada 83 compatibility)
6225 -- Ada 83 attribute is defined as (RM83 3.5.8)
6227 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6231 -- T'Emax = 4 * T'Mantissa
6234 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6242 when Attribute_Last => Last :
6246 if Compile_Time_Known_Value (Hi_Bound) then
6247 if Is_Real_Type (P_Type) then
6248 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6250 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6254 Check_Concurrent_Discriminant (Hi_Bound);
6262 when Attribute_Leading_Part =>
6264 Eval_Fat.Leading_Part
6265 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6271 when Attribute_Length => Length : declare
6275 -- If any index type is a formal type, or derived from one, the
6276 -- bounds are not static. Treating them as static can produce
6277 -- spurious warnings or improper constant folding.
6279 Ind := First_Index (P_Type);
6280 while Present (Ind) loop
6281 if Is_Generic_Type (Root_Type (Etype (Ind))) then
6290 -- For two compile time values, we can compute length
6292 if Compile_Time_Known_Value (Lo_Bound)
6293 and then Compile_Time_Known_Value (Hi_Bound)
6296 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6300 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6301 -- comparable, and we can figure out the difference between them.
6304 Diff : aliased Uint;
6308 Compile_Time_Compare
6309 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6312 Fold_Uint (N, Uint_1, False);
6315 Fold_Uint (N, Uint_0, False);
6318 if Diff /= No_Uint then
6319 Fold_Uint (N, Diff + 1, False);
6332 when Attribute_Machine =>
6335 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6342 when Attribute_Machine_Emax =>
6343 Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
6349 when Attribute_Machine_Emin =>
6350 Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
6352 ----------------------
6353 -- Machine_Mantissa --
6354 ----------------------
6356 when Attribute_Machine_Mantissa =>
6357 Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
6359 -----------------------
6360 -- Machine_Overflows --
6361 -----------------------
6363 when Attribute_Machine_Overflows =>
6365 -- Always true for fixed-point
6367 if Is_Fixed_Point_Type (P_Type) then
6368 Fold_Uint (N, True_Value, True);
6370 -- Floating point case
6374 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6382 when Attribute_Machine_Radix =>
6383 if Is_Fixed_Point_Type (P_Type) then
6384 if Is_Decimal_Fixed_Point_Type (P_Type)
6385 and then Machine_Radix_10 (P_Type)
6387 Fold_Uint (N, Uint_10, True);
6389 Fold_Uint (N, Uint_2, True);
6392 -- All floating-point type always have radix 2
6395 Fold_Uint (N, Uint_2, True);
6398 ----------------------
6399 -- Machine_Rounding --
6400 ----------------------
6402 -- Note: for the folding case, it is fine to treat Machine_Rounding
6403 -- exactly the same way as Rounding, since this is one of the allowed
6404 -- behaviors, and performance is not an issue here. It might be a bit
6405 -- better to give the same result as it would give at run time, even
6406 -- though the non-determinism is certainly permitted.
6408 when Attribute_Machine_Rounding =>
6410 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6412 --------------------
6413 -- Machine_Rounds --
6414 --------------------
6416 when Attribute_Machine_Rounds =>
6418 -- Always False for fixed-point
6420 if Is_Fixed_Point_Type (P_Type) then
6421 Fold_Uint (N, False_Value, True);
6423 -- Else yield proper floating-point result
6427 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6434 -- Note: Machine_Size is identical to Object_Size
6436 when Attribute_Machine_Size => Machine_Size : declare
6437 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6440 if Known_Esize (P_TypeA) then
6441 Fold_Uint (N, Esize (P_TypeA), True);
6449 when Attribute_Mantissa =>
6451 -- Fixed-point mantissa
6453 if Is_Fixed_Point_Type (P_Type) then
6455 -- Compile time foldable case
6457 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6459 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6461 -- The calculation of the obsolete Ada 83 attribute Mantissa
6462 -- is annoying, because of AI00143, quoted here:
6464 -- !question 84-01-10
6466 -- Consider the model numbers for F:
6468 -- type F is delta 1.0 range -7.0 .. 8.0;
6470 -- The wording requires that F'MANTISSA be the SMALLEST
6471 -- integer number for which each bound of the specified
6472 -- range is either a model number or lies at most small
6473 -- distant from a model number. This means F'MANTISSA
6474 -- is required to be 3 since the range -7.0 .. 7.0 fits
6475 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6476 -- number, namely, 7. Is this analysis correct? Note that
6477 -- this implies the upper bound of the range is not
6478 -- represented as a model number.
6480 -- !response 84-03-17
6482 -- The analysis is correct. The upper and lower bounds for
6483 -- a fixed point type can lie outside the range of model
6494 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6495 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6496 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6497 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6499 -- If the Bound is exactly a model number, i.e. a multiple
6500 -- of Small, then we back it off by one to get the integer
6501 -- value that must be representable.
6503 if Small_Value (P_Type) * Max_Man = Bound then
6504 Max_Man := Max_Man - 1;
6507 -- Now find corresponding size = Mantissa value
6510 while 2 ** Siz < Max_Man loop
6514 Fold_Uint (N, Siz, True);
6518 -- The case of dynamic bounds cannot be evaluated at compile
6519 -- time. Instead we use a runtime routine (see Exp_Attr).
6524 -- Floating-point Mantissa
6527 Fold_Uint (N, Mantissa, True);
6534 when Attribute_Max => Max :
6536 if Is_Real_Type (P_Type) then
6538 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6540 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6544 ----------------------------------
6545 -- Max_Alignment_For_Allocation --
6546 ----------------------------------
6548 -- Max_Alignment_For_Allocation is usually the Alignment. However,
6549 -- arrays are allocated with dope, so we need to take into account both
6550 -- the alignment of the array, which comes from the component alignment,
6551 -- and the alignment of the dope. Also, if the alignment is unknown, we
6552 -- use the max (it's OK to be pessimistic).
6554 when Attribute_Max_Alignment_For_Allocation =>
6556 A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
6558 if Known_Alignment (P_Type) and then
6559 (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
6561 A := Alignment (P_Type);
6564 Fold_Uint (N, A, Static);
6567 ----------------------------------
6568 -- Max_Size_In_Storage_Elements --
6569 ----------------------------------
6571 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6572 -- Storage_Unit boundary. We can fold any cases for which the size
6573 -- is known by the front end.
6575 when Attribute_Max_Size_In_Storage_Elements =>
6576 if Known_Esize (P_Type) then
6578 (Esize (P_Type) + System_Storage_Unit - 1) /
6579 System_Storage_Unit,
6583 --------------------
6584 -- Mechanism_Code --
6585 --------------------
6587 when Attribute_Mechanism_Code =>
6591 Mech : Mechanism_Type;
6595 Mech := Mechanism (P_Entity);
6598 Val := UI_To_Int (Expr_Value (E1));
6600 Formal := First_Formal (P_Entity);
6601 for J in 1 .. Val - 1 loop
6602 Next_Formal (Formal);
6604 Mech := Mechanism (Formal);
6608 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6616 when Attribute_Min => Min :
6618 if Is_Real_Type (P_Type) then
6620 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6623 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6631 when Attribute_Mod =>
6633 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6639 when Attribute_Model =>
6641 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
6647 when Attribute_Model_Emin =>
6648 Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
6654 when Attribute_Model_Epsilon =>
6655 Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
6657 --------------------
6658 -- Model_Mantissa --
6659 --------------------
6661 when Attribute_Model_Mantissa =>
6662 Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
6668 when Attribute_Model_Small =>
6669 Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
6675 when Attribute_Modulus =>
6676 Fold_Uint (N, Modulus (P_Type), True);
6678 --------------------
6679 -- Null_Parameter --
6680 --------------------
6682 -- Cannot fold, we know the value sort of, but the whole point is
6683 -- that there is no way to talk about this imaginary value except
6684 -- by using the attribute, so we leave it the way it is.
6686 when Attribute_Null_Parameter =>
6693 -- The Object_Size attribute for a type returns the Esize of the
6694 -- type and can be folded if this value is known.
6696 when Attribute_Object_Size => Object_Size : declare
6697 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6700 if Known_Esize (P_TypeA) then
6701 Fold_Uint (N, Esize (P_TypeA), True);
6705 -------------------------
6706 -- Passed_By_Reference --
6707 -------------------------
6709 -- Scalar types are never passed by reference
6711 when Attribute_Passed_By_Reference =>
6712 Fold_Uint (N, False_Value, True);
6718 when Attribute_Pos =>
6719 Fold_Uint (N, Expr_Value (E1), True);
6725 when Attribute_Pred => Pred :
6727 -- Floating-point case
6729 if Is_Floating_Point_Type (P_Type) then
6731 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
6735 elsif Is_Fixed_Point_Type (P_Type) then
6737 Expr_Value_R (E1) - Small_Value (P_Type), True);
6739 -- Modular integer case (wraps)
6741 elsif Is_Modular_Integer_Type (P_Type) then
6742 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
6744 -- Other scalar cases
6747 pragma Assert (Is_Scalar_Type (P_Type));
6749 if Is_Enumeration_Type (P_Type)
6750 and then Expr_Value (E1) =
6751 Expr_Value (Type_Low_Bound (P_Base_Type))
6753 Apply_Compile_Time_Constraint_Error
6754 (N, "Pred of `&''First`",
6755 CE_Overflow_Check_Failed,
6757 Warn => not Static);
6763 Fold_Uint (N, Expr_Value (E1) - 1, Static);
6771 -- No processing required, because by this stage, Range has been
6772 -- replaced by First .. Last, so this branch can never be taken.
6774 when Attribute_Range =>
6775 raise Program_Error;
6781 when Attribute_Range_Length =>
6784 -- Can fold if both bounds are compile time known
6786 if Compile_Time_Known_Value (Hi_Bound)
6787 and then Compile_Time_Known_Value (Lo_Bound)
6791 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
6795 -- One more case is where Hi_Bound and Lo_Bound are compile-time
6796 -- comparable, and we can figure out the difference between them.
6799 Diff : aliased Uint;
6803 Compile_Time_Compare
6804 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
6807 Fold_Uint (N, Uint_1, False);
6810 Fold_Uint (N, Uint_0, False);
6813 if Diff /= No_Uint then
6814 Fold_Uint (N, Diff + 1, False);
6826 when Attribute_Ref =>
6827 Fold_Uint (N, Expr_Value (E1), True);
6833 when Attribute_Remainder => Remainder : declare
6834 X : constant Ureal := Expr_Value_R (E1);
6835 Y : constant Ureal := Expr_Value_R (E2);
6838 if UR_Is_Zero (Y) then
6839 Apply_Compile_Time_Constraint_Error
6840 (N, "division by zero in Remainder",
6841 CE_Overflow_Check_Failed,
6842 Warn => not Static);
6848 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
6855 when Attribute_Round => Round :
6861 -- First we get the (exact result) in units of small
6863 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
6865 -- Now round that exactly to an integer
6867 Si := UR_To_Uint (Sr);
6869 -- Finally the result is obtained by converting back to real
6871 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
6878 when Attribute_Rounding =>
6880 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6886 when Attribute_Safe_Emax =>
6887 Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
6893 when Attribute_Safe_First =>
6894 Fold_Ureal (N, Safe_First_Value (P_Type), Static);
6900 when Attribute_Safe_Large =>
6901 if Is_Fixed_Point_Type (P_Type) then
6903 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
6905 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
6912 when Attribute_Safe_Last =>
6913 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
6919 when Attribute_Safe_Small =>
6921 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
6922 -- for fixed-point, since is the same as Small, but we implement
6923 -- it for backwards compatibility.
6925 if Is_Fixed_Point_Type (P_Type) then
6926 Fold_Ureal (N, Small_Value (P_Type), Static);
6928 -- Ada 83 Safe_Small for floating-point cases
6931 Fold_Ureal (N, Model_Small_Value (P_Type), Static);
6938 when Attribute_Scale =>
6939 Fold_Uint (N, Scale_Value (P_Type), True);
6945 when Attribute_Scaling =>
6948 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6954 when Attribute_Signed_Zeros =>
6956 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
6962 -- Size attribute returns the RM size. All scalar types can be folded,
6963 -- as well as any types for which the size is known by the front end,
6964 -- including any type for which a size attribute is specified.
6966 when Attribute_Size | Attribute_VADS_Size => Size : declare
6967 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6970 if RM_Size (P_TypeA) /= Uint_0 then
6974 if Id = Attribute_VADS_Size or else Use_VADS_Size then
6976 S : constant Node_Id := Size_Clause (P_TypeA);
6979 -- If a size clause applies, then use the size from it.
6980 -- This is one of the rare cases where we can use the
6981 -- Size_Clause field for a subtype when Has_Size_Clause
6982 -- is False. Consider:
6984 -- type x is range 1 .. 64;
6985 -- for x'size use 12;
6986 -- subtype y is x range 0 .. 3;
6988 -- Here y has a size clause inherited from x, but normally
6989 -- it does not apply, and y'size is 2. However, y'VADS_Size
6990 -- is indeed 12 and not 2.
6993 and then Is_OK_Static_Expression (Expression (S))
6995 Fold_Uint (N, Expr_Value (Expression (S)), True);
6997 -- If no size is specified, then we simply use the object
6998 -- size in the VADS_Size case (e.g. Natural'Size is equal
6999 -- to Integer'Size, not one less).
7002 Fold_Uint (N, Esize (P_TypeA), True);
7006 -- Normal case (Size) in which case we want the RM_Size
7011 Static and then Is_Discrete_Type (P_TypeA));
7020 when Attribute_Small =>
7022 -- The floating-point case is present only for Ada 83 compatibility.
7023 -- Note that strictly this is an illegal addition, since we are
7024 -- extending an Ada 95 defined attribute, but we anticipate an
7025 -- ARG ruling that will permit this.
7027 if Is_Floating_Point_Type (P_Type) then
7029 -- Ada 83 attribute is defined as (RM83 3.5.8)
7031 -- T'Small = 2.0**(-T'Emax - 1)
7035 -- T'Emax = 4 * T'Mantissa
7037 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
7039 -- Normal Ada 95 fixed-point case
7042 Fold_Ureal (N, Small_Value (P_Type), True);
7049 when Attribute_Stream_Size =>
7056 when Attribute_Succ => Succ :
7058 -- Floating-point case
7060 if Is_Floating_Point_Type (P_Type) then
7062 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
7066 elsif Is_Fixed_Point_Type (P_Type) then
7068 Expr_Value_R (E1) + Small_Value (P_Type), Static);
7070 -- Modular integer case (wraps)
7072 elsif Is_Modular_Integer_Type (P_Type) then
7073 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
7075 -- Other scalar cases
7078 pragma Assert (Is_Scalar_Type (P_Type));
7080 if Is_Enumeration_Type (P_Type)
7081 and then Expr_Value (E1) =
7082 Expr_Value (Type_High_Bound (P_Base_Type))
7084 Apply_Compile_Time_Constraint_Error
7085 (N, "Succ of `&''Last`",
7086 CE_Overflow_Check_Failed,
7088 Warn => not Static);
7093 Fold_Uint (N, Expr_Value (E1) + 1, Static);
7102 when Attribute_Truncation =>
7104 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
7110 when Attribute_Type_Class => Type_Class : declare
7111 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
7115 if Is_Descendent_Of_Address (Typ) then
7116 Id := RE_Type_Class_Address;
7118 elsif Is_Enumeration_Type (Typ) then
7119 Id := RE_Type_Class_Enumeration;
7121 elsif Is_Integer_Type (Typ) then
7122 Id := RE_Type_Class_Integer;
7124 elsif Is_Fixed_Point_Type (Typ) then
7125 Id := RE_Type_Class_Fixed_Point;
7127 elsif Is_Floating_Point_Type (Typ) then
7128 Id := RE_Type_Class_Floating_Point;
7130 elsif Is_Array_Type (Typ) then
7131 Id := RE_Type_Class_Array;
7133 elsif Is_Record_Type (Typ) then
7134 Id := RE_Type_Class_Record;
7136 elsif Is_Access_Type (Typ) then
7137 Id := RE_Type_Class_Access;
7139 elsif Is_Enumeration_Type (Typ) then
7140 Id := RE_Type_Class_Enumeration;
7142 elsif Is_Task_Type (Typ) then
7143 Id := RE_Type_Class_Task;
7145 -- We treat protected types like task types. It would make more
7146 -- sense to have another enumeration value, but after all the
7147 -- whole point of this feature is to be exactly DEC compatible,
7148 -- and changing the type Type_Class would not meet this requirement.
7150 elsif Is_Protected_Type (Typ) then
7151 Id := RE_Type_Class_Task;
7153 -- Not clear if there are any other possibilities, but if there
7154 -- are, then we will treat them as the address case.
7157 Id := RE_Type_Class_Address;
7160 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
7163 -----------------------
7164 -- Unbiased_Rounding --
7165 -----------------------
7167 when Attribute_Unbiased_Rounding =>
7169 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7172 -------------------------
7173 -- Unconstrained_Array --
7174 -------------------------
7176 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7177 Typ : constant Entity_Id := Underlying_Type (P_Type);
7180 Rewrite (N, New_Occurrence_Of (
7182 Is_Array_Type (P_Type)
7183 and then not Is_Constrained (Typ)), Loc));
7185 -- Analyze and resolve as boolean, note that this attribute is
7186 -- a static attribute in GNAT.
7188 Analyze_And_Resolve (N, Standard_Boolean);
7190 end Unconstrained_Array;
7196 -- Processing is shared with Size
7202 when Attribute_Val => Val :
7204 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7206 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7208 Apply_Compile_Time_Constraint_Error
7209 (N, "Val expression out of range",
7210 CE_Range_Check_Failed,
7211 Warn => not Static);
7217 Fold_Uint (N, Expr_Value (E1), Static);
7225 -- The Value_Size attribute for a type returns the RM size of the
7226 -- type. This an always be folded for scalar types, and can also
7227 -- be folded for non-scalar types if the size is set.
7229 when Attribute_Value_Size => Value_Size : declare
7230 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7232 if RM_Size (P_TypeA) /= Uint_0 then
7233 Fold_Uint (N, RM_Size (P_TypeA), True);
7241 -- Version can never be static
7243 when Attribute_Version =>
7250 -- Wide_Image is a scalar attribute, but is never static, because it
7251 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7253 when Attribute_Wide_Image =>
7256 ---------------------
7257 -- Wide_Wide_Image --
7258 ---------------------
7260 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7261 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7263 when Attribute_Wide_Wide_Image =>
7266 ---------------------
7267 -- Wide_Wide_Width --
7268 ---------------------
7270 -- Processing for Wide_Wide_Width is combined with Width
7276 -- Processing for Wide_Width is combined with Width
7282 -- This processing also handles the case of Wide_[Wide_]Width
7284 when Attribute_Width |
7285 Attribute_Wide_Width |
7286 Attribute_Wide_Wide_Width => Width :
7288 if Compile_Time_Known_Bounds (P_Type) then
7290 -- Floating-point types
7292 if Is_Floating_Point_Type (P_Type) then
7294 -- Width is zero for a null range (RM 3.5 (38))
7296 if Expr_Value_R (Type_High_Bound (P_Type)) <
7297 Expr_Value_R (Type_Low_Bound (P_Type))
7299 Fold_Uint (N, Uint_0, True);
7302 -- For floating-point, we have +N.dddE+nnn where length
7303 -- of ddd is determined by type'Digits - 1, but is one
7304 -- if Digits is one (RM 3.5 (33)).
7306 -- nnn is set to 2 for Short_Float and Float (32 bit
7307 -- floats), and 3 for Long_Float and Long_Long_Float.
7308 -- For machines where Long_Long_Float is the IEEE
7309 -- extended precision type, the exponent takes 4 digits.
7313 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7316 if Esize (P_Type) <= 32 then
7318 elsif Esize (P_Type) = 64 then
7324 Fold_Uint (N, UI_From_Int (Len), True);
7328 -- Fixed-point types
7330 elsif Is_Fixed_Point_Type (P_Type) then
7332 -- Width is zero for a null range (RM 3.5 (38))
7334 if Expr_Value (Type_High_Bound (P_Type)) <
7335 Expr_Value (Type_Low_Bound (P_Type))
7337 Fold_Uint (N, Uint_0, True);
7339 -- The non-null case depends on the specific real type
7342 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7345 (N, UI_From_Int (Fore_Value + 1) + Aft_Value (P_Type),
7353 R : constant Entity_Id := Root_Type (P_Type);
7354 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7355 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7368 -- Width for types derived from Standard.Character
7369 -- and Standard.Wide_[Wide_]Character.
7371 elsif Is_Standard_Character_Type (P_Type) then
7374 -- Set W larger if needed
7376 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7378 -- All wide characters look like Hex_hhhhhhhh
7382 -- No need to compute this more than once!
7387 C := Character'Val (J);
7389 -- Test for all cases where Character'Image
7390 -- yields an image that is longer than three
7391 -- characters. First the cases of Reserved_xxx
7392 -- names (length = 12).
7395 when Reserved_128 | Reserved_129 |
7396 Reserved_132 | Reserved_153
7399 when BS | HT | LF | VT | FF | CR |
7400 SO | SI | EM | FS | GS | RS |
7401 US | RI | MW | ST | PM
7404 when NUL | SOH | STX | ETX | EOT |
7405 ENQ | ACK | BEL | DLE | DC1 |
7406 DC2 | DC3 | DC4 | NAK | SYN |
7407 ETB | CAN | SUB | ESC | DEL |
7408 BPH | NBH | NEL | SSA | ESA |
7409 HTS | HTJ | VTS | PLD | PLU |
7410 SS2 | SS3 | DCS | PU1 | PU2 |
7411 STS | CCH | SPA | EPA | SOS |
7412 SCI | CSI | OSC | APC
7415 when Space .. Tilde |
7416 No_Break_Space .. LC_Y_Diaeresis
7418 -- Special case of soft hyphen in Ada 2005
7420 if C = Character'Val (16#AD#)
7421 and then Ada_Version >= Ada_2005
7429 W := Int'Max (W, Wt);
7433 -- Width for types derived from Standard.Boolean
7435 elsif R = Standard_Boolean then
7442 -- Width for integer types
7444 elsif Is_Integer_Type (P_Type) then
7445 T := UI_Max (abs Lo, abs Hi);
7453 -- Only remaining possibility is user declared enum type
7456 pragma Assert (Is_Enumeration_Type (P_Type));
7459 L := First_Literal (P_Type);
7461 while Present (L) loop
7463 -- Only pay attention to in range characters
7465 if Lo <= Enumeration_Pos (L)
7466 and then Enumeration_Pos (L) <= Hi
7468 -- For Width case, use decoded name
7470 if Id = Attribute_Width then
7471 Get_Decoded_Name_String (Chars (L));
7472 Wt := Nat (Name_Len);
7474 -- For Wide_[Wide_]Width, use encoded name, and
7475 -- then adjust for the encoding.
7478 Get_Name_String (Chars (L));
7480 -- Character literals are always of length 3
7482 if Name_Buffer (1) = 'Q' then
7485 -- Otherwise loop to adjust for upper/wide chars
7488 Wt := Nat (Name_Len);
7490 for J in 1 .. Name_Len loop
7491 if Name_Buffer (J) = 'U' then
7493 elsif Name_Buffer (J) = 'W' then
7500 W := Int'Max (W, Wt);
7507 Fold_Uint (N, UI_From_Int (W), True);
7513 -- The following attributes denote functions that cannot be folded
7515 when Attribute_From_Any |
7517 Attribute_TypeCode =>
7520 -- The following attributes can never be folded, and furthermore we
7521 -- should not even have entered the case statement for any of these.
7522 -- Note that in some cases, the values have already been folded as
7523 -- a result of the processing in Analyze_Attribute.
7525 when Attribute_Abort_Signal |
7528 Attribute_Address_Size |
7529 Attribute_Asm_Input |
7530 Attribute_Asm_Output |
7532 Attribute_Bit_Order |
7533 Attribute_Bit_Position |
7534 Attribute_Callable |
7537 Attribute_Code_Address |
7538 Attribute_Compiler_Version |
7540 Attribute_Default_Bit_Order |
7541 Attribute_Elaborated |
7542 Attribute_Elab_Body |
7543 Attribute_Elab_Spec |
7545 Attribute_External_Tag |
7546 Attribute_Fast_Math |
7547 Attribute_First_Bit |
7549 Attribute_Last_Bit |
7550 Attribute_Maximum_Alignment |
7553 Attribute_Partition_ID |
7554 Attribute_Pool_Address |
7555 Attribute_Position |
7556 Attribute_Priority |
7559 Attribute_Storage_Pool |
7560 Attribute_Storage_Size |
7561 Attribute_Storage_Unit |
7562 Attribute_Stub_Type |
7564 Attribute_Target_Name |
7565 Attribute_Terminated |
7566 Attribute_To_Address |
7567 Attribute_Type_Key |
7568 Attribute_UET_Address |
7569 Attribute_Unchecked_Access |
7570 Attribute_Universal_Literal_String |
7571 Attribute_Unrestricted_Access |
7574 Attribute_Wchar_T_Size |
7575 Attribute_Wide_Value |
7576 Attribute_Wide_Wide_Value |
7577 Attribute_Word_Size |
7580 raise Program_Error;
7583 -- At the end of the case, one more check. If we did a static evaluation
7584 -- so that the result is now a literal, then set Is_Static_Expression
7585 -- in the constant only if the prefix type is a static subtype. For
7586 -- non-static subtypes, the folding is still OK, but not static.
7588 -- An exception is the GNAT attribute Constrained_Array which is
7589 -- defined to be a static attribute in all cases.
7591 if Nkind_In (N, N_Integer_Literal,
7593 N_Character_Literal,
7595 or else (Is_Entity_Name (N)
7596 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7598 Set_Is_Static_Expression (N, Static);
7600 -- If this is still an attribute reference, then it has not been folded
7601 -- and that means that its expressions are in a non-static context.
7603 elsif Nkind (N) = N_Attribute_Reference then
7606 -- Note: the else case not covered here are odd cases where the
7607 -- processing has transformed the attribute into something other
7608 -- than a constant. Nothing more to do in such cases.
7615 ------------------------------
7616 -- Is_Anonymous_Tagged_Base --
7617 ------------------------------
7619 function Is_Anonymous_Tagged_Base
7626 Anon = Current_Scope
7627 and then Is_Itype (Anon)
7628 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
7629 end Is_Anonymous_Tagged_Base;
7631 --------------------------------
7632 -- Name_Implies_Lvalue_Prefix --
7633 --------------------------------
7635 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
7636 pragma Assert (Is_Attribute_Name (Nam));
7638 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
7639 end Name_Implies_Lvalue_Prefix;
7641 -----------------------
7642 -- Resolve_Attribute --
7643 -----------------------
7645 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
7646 Loc : constant Source_Ptr := Sloc (N);
7647 P : constant Node_Id := Prefix (N);
7648 Aname : constant Name_Id := Attribute_Name (N);
7649 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7650 Btyp : constant Entity_Id := Base_Type (Typ);
7651 Des_Btyp : Entity_Id;
7652 Index : Interp_Index;
7654 Nom_Subt : Entity_Id;
7656 procedure Accessibility_Message;
7657 -- Error, or warning within an instance, if the static accessibility
7658 -- rules of 3.10.2 are violated.
7660 ---------------------------
7661 -- Accessibility_Message --
7662 ---------------------------
7664 procedure Accessibility_Message is
7665 Indic : Node_Id := Parent (Parent (N));
7668 -- In an instance, this is a runtime check, but one we
7669 -- know will fail, so generate an appropriate warning.
7671 if In_Instance_Body then
7672 Error_Msg_F ("?non-local pointer cannot point to local object", P);
7674 ("\?Program_Error will be raised at run time", P);
7676 Make_Raise_Program_Error (Loc,
7677 Reason => PE_Accessibility_Check_Failed));
7682 Error_Msg_F ("non-local pointer cannot point to local object", P);
7684 -- Check for case where we have a missing access definition
7686 if Is_Record_Type (Current_Scope)
7688 Nkind_In (Parent (N), N_Discriminant_Association,
7689 N_Index_Or_Discriminant_Constraint)
7691 Indic := Parent (Parent (N));
7692 while Present (Indic)
7693 and then Nkind (Indic) /= N_Subtype_Indication
7695 Indic := Parent (Indic);
7698 if Present (Indic) then
7700 ("\use an access definition for" &
7701 " the access discriminant of&",
7702 N, Entity (Subtype_Mark (Indic)));
7706 end Accessibility_Message;
7708 -- Start of processing for Resolve_Attribute
7711 -- If error during analysis, no point in continuing, except for array
7712 -- types, where we get better recovery by using unconstrained indexes
7713 -- than nothing at all (see Check_Array_Type).
7716 and then Attr_Id /= Attribute_First
7717 and then Attr_Id /= Attribute_Last
7718 and then Attr_Id /= Attribute_Length
7719 and then Attr_Id /= Attribute_Range
7724 -- If attribute was universal type, reset to actual type
7726 if Etype (N) = Universal_Integer
7727 or else Etype (N) = Universal_Real
7732 -- Remaining processing depends on attribute
7740 -- For access attributes, if the prefix denotes an entity, it is
7741 -- interpreted as a name, never as a call. It may be overloaded,
7742 -- in which case resolution uses the profile of the context type.
7743 -- Otherwise prefix must be resolved.
7745 when Attribute_Access
7746 | Attribute_Unchecked_Access
7747 | Attribute_Unrestricted_Access =>
7751 if Is_Variable (P) then
7752 Note_Possible_Modification (P, Sure => False);
7755 -- The following comes from a query by Adam Beneschan, concerning
7756 -- improper use of universal_access in equality tests involving
7757 -- anonymous access types. Another good reason for 'Ref, but
7758 -- for now disable the test, which breaks several filed tests.
7760 if Ekind (Typ) = E_Anonymous_Access_Type
7761 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
7764 Error_Msg_N ("need unique type to resolve 'Access", N);
7765 Error_Msg_N ("\qualify attribute with some access type", N);
7768 if Is_Entity_Name (P) then
7769 if Is_Overloaded (P) then
7770 Get_First_Interp (P, Index, It);
7771 while Present (It.Nam) loop
7772 if Type_Conformant (Designated_Type (Typ), It.Nam) then
7773 Set_Entity (P, It.Nam);
7775 -- The prefix is definitely NOT overloaded anymore at
7776 -- this point, so we reset the Is_Overloaded flag to
7777 -- avoid any confusion when reanalyzing the node.
7779 Set_Is_Overloaded (P, False);
7780 Set_Is_Overloaded (N, False);
7781 Generate_Reference (Entity (P), P);
7785 Get_Next_Interp (Index, It);
7788 -- If Prefix is a subprogram name, it is frozen by this
7791 -- If it is a type, there is nothing to resolve.
7792 -- If it is an object, complete its resolution.
7794 elsif Is_Overloadable (Entity (P)) then
7796 -- Avoid insertion of freeze actions in spec expression mode
7798 if not In_Spec_Expression then
7799 Freeze_Before (N, Entity (P));
7802 elsif Is_Type (Entity (P)) then
7808 Error_Msg_Name_1 := Aname;
7810 if not Is_Entity_Name (P) then
7813 elsif Is_Overloadable (Entity (P))
7814 and then Is_Abstract_Subprogram (Entity (P))
7816 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
7817 Set_Etype (N, Any_Type);
7819 elsif Convention (Entity (P)) = Convention_Intrinsic then
7820 if Ekind (Entity (P)) = E_Enumeration_Literal then
7822 ("prefix of % attribute cannot be enumeration literal",
7826 ("prefix of % attribute cannot be intrinsic", P);
7829 Set_Etype (N, Any_Type);
7832 -- Assignments, return statements, components of aggregates,
7833 -- generic instantiations will require convention checks if
7834 -- the type is an access to subprogram. Given that there will
7835 -- also be accessibility checks on those, this is where the
7836 -- checks can eventually be centralized ???
7838 if Ekind_In (Btyp, E_Access_Subprogram_Type,
7839 E_Anonymous_Access_Subprogram_Type,
7840 E_Anonymous_Access_Protected_Subprogram_Type)
7842 -- Deal with convention mismatch
7844 if Convention (Btyp) /= Convention (Entity (P)) then
7846 ("subprogram & has wrong convention", P, Entity (P));
7849 ("\does not match convention of access type &",
7852 if not Has_Convention_Pragma (Btyp) then
7854 ("\probable missing pragma Convention for &",
7859 Check_Subtype_Conformant
7860 (New_Id => Entity (P),
7861 Old_Id => Designated_Type (Btyp),
7865 if Attr_Id = Attribute_Unchecked_Access then
7866 Error_Msg_Name_1 := Aname;
7868 ("attribute% cannot be applied to a subprogram", P);
7870 elsif Aname = Name_Unrestricted_Access then
7871 null; -- Nothing to check
7873 -- Check the static accessibility rule of 3.10.2(32).
7874 -- This rule also applies within the private part of an
7875 -- instantiation. This rule does not apply to anonymous
7876 -- access-to-subprogram types in access parameters.
7878 elsif Attr_Id = Attribute_Access
7879 and then not In_Instance_Body
7881 (Ekind (Btyp) = E_Access_Subprogram_Type
7882 or else Is_Local_Anonymous_Access (Btyp))
7884 and then Subprogram_Access_Level (Entity (P)) >
7885 Type_Access_Level (Btyp)
7888 ("subprogram must not be deeper than access type", P);
7890 -- Check the restriction of 3.10.2(32) that disallows the
7891 -- access attribute within a generic body when the ultimate
7892 -- ancestor of the type of the attribute is declared outside
7893 -- of the generic unit and the subprogram is declared within
7894 -- that generic unit. This includes any such attribute that
7895 -- occurs within the body of a generic unit that is a child
7896 -- of the generic unit where the subprogram is declared.
7898 -- The rule also prohibits applying the attribute when the
7899 -- access type is a generic formal access type (since the
7900 -- level of the actual type is not known). This restriction
7901 -- does not apply when the attribute type is an anonymous
7902 -- access-to-subprogram type. Note that this check was
7903 -- revised by AI-229, because the originally Ada 95 rule
7904 -- was too lax. The original rule only applied when the
7905 -- subprogram was declared within the body of the generic,
7906 -- which allowed the possibility of dangling references).
7907 -- The rule was also too strict in some case, in that it
7908 -- didn't permit the access to be declared in the generic
7909 -- spec, whereas the revised rule does (as long as it's not
7912 -- There are a couple of subtleties of the test for applying
7913 -- the check that are worth noting. First, we only apply it
7914 -- when the levels of the subprogram and access type are the
7915 -- same (the case where the subprogram is statically deeper
7916 -- was applied above, and the case where the type is deeper
7917 -- is always safe). Second, we want the check to apply
7918 -- within nested generic bodies and generic child unit
7919 -- bodies, but not to apply to an attribute that appears in
7920 -- the generic unit's specification. This is done by testing
7921 -- that the attribute's innermost enclosing generic body is
7922 -- not the same as the innermost generic body enclosing the
7923 -- generic unit where the subprogram is declared (we don't
7924 -- want the check to apply when the access attribute is in
7925 -- the spec and there's some other generic body enclosing
7926 -- generic). Finally, there's no point applying the check
7927 -- when within an instance, because any violations will have
7928 -- been caught by the compilation of the generic unit.
7930 -- Note that we relax this check in CodePeer mode for
7931 -- compatibility with legacy code, since CodePeer is an
7932 -- Ada source code analyzer, not a strict compiler.
7933 -- ??? Note that a better approach would be to have a
7934 -- separate switch to relax this rule, and enable this
7935 -- switch in CodePeer mode.
7937 elsif Attr_Id = Attribute_Access
7938 and then not CodePeer_Mode
7939 and then not In_Instance
7940 and then Present (Enclosing_Generic_Unit (Entity (P)))
7941 and then Present (Enclosing_Generic_Body (N))
7942 and then Enclosing_Generic_Body (N) /=
7943 Enclosing_Generic_Body
7944 (Enclosing_Generic_Unit (Entity (P)))
7945 and then Subprogram_Access_Level (Entity (P)) =
7946 Type_Access_Level (Btyp)
7947 and then Ekind (Btyp) /=
7948 E_Anonymous_Access_Subprogram_Type
7949 and then Ekind (Btyp) /=
7950 E_Anonymous_Access_Protected_Subprogram_Type
7952 -- The attribute type's ultimate ancestor must be
7953 -- declared within the same generic unit as the
7954 -- subprogram is declared. The error message is
7955 -- specialized to say "ancestor" for the case where the
7956 -- access type is not its own ancestor, since saying
7957 -- simply "access type" would be very confusing.
7959 if Enclosing_Generic_Unit (Entity (P)) /=
7960 Enclosing_Generic_Unit (Root_Type (Btyp))
7963 ("''Access attribute not allowed in generic body",
7966 if Root_Type (Btyp) = Btyp then
7969 "access type & is declared outside " &
7970 "generic unit (RM 3.10.2(32))", N, Btyp);
7973 ("\because ancestor of " &
7974 "access type & is declared outside " &
7975 "generic unit (RM 3.10.2(32))", N, Btyp);
7979 ("\move ''Access to private part, or " &
7980 "(Ada 2005) use anonymous access type instead of &",
7983 -- If the ultimate ancestor of the attribute's type is
7984 -- a formal type, then the attribute is illegal because
7985 -- the actual type might be declared at a higher level.
7986 -- The error message is specialized to say "ancestor"
7987 -- for the case where the access type is not its own
7988 -- ancestor, since saying simply "access type" would be
7991 elsif Is_Generic_Type (Root_Type (Btyp)) then
7992 if Root_Type (Btyp) = Btyp then
7994 ("access type must not be a generic formal type",
7998 ("ancestor access type must not be a generic " &
8005 -- If this is a renaming, an inherited operation, or a
8006 -- subprogram instance, use the original entity. This may make
8007 -- the node type-inconsistent, so this transformation can only
8008 -- be done if the node will not be reanalyzed. In particular,
8009 -- if it is within a default expression, the transformation
8010 -- must be delayed until the default subprogram is created for
8011 -- it, when the enclosing subprogram is frozen.
8013 if Is_Entity_Name (P)
8014 and then Is_Overloadable (Entity (P))
8015 and then Present (Alias (Entity (P)))
8016 and then Expander_Active
8019 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8022 elsif Nkind (P) = N_Selected_Component
8023 and then Is_Overloadable (Entity (Selector_Name (P)))
8025 -- Protected operation. If operation is overloaded, must
8026 -- disambiguate. Prefix that denotes protected object itself
8027 -- is resolved with its own type.
8029 if Attr_Id = Attribute_Unchecked_Access then
8030 Error_Msg_Name_1 := Aname;
8032 ("attribute% cannot be applied to protected operation", P);
8035 Resolve (Prefix (P));
8036 Generate_Reference (Entity (Selector_Name (P)), P);
8038 elsif Is_Overloaded (P) then
8040 -- Use the designated type of the context to disambiguate
8041 -- Note that this was not strictly conformant to Ada 95,
8042 -- but was the implementation adopted by most Ada 95 compilers.
8043 -- The use of the context type to resolve an Access attribute
8044 -- reference is now mandated in AI-235 for Ada 2005.
8047 Index : Interp_Index;
8051 Get_First_Interp (P, Index, It);
8052 while Present (It.Typ) loop
8053 if Covers (Designated_Type (Typ), It.Typ) then
8054 Resolve (P, It.Typ);
8058 Get_Next_Interp (Index, It);
8065 -- X'Access is illegal if X denotes a constant and the access type
8066 -- is access-to-variable. Same for 'Unchecked_Access. The rule
8067 -- does not apply to 'Unrestricted_Access. If the reference is a
8068 -- default-initialized aggregate component for a self-referential
8069 -- type the reference is legal.
8071 if not (Ekind (Btyp) = E_Access_Subprogram_Type
8072 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
8073 or else (Is_Record_Type (Btyp)
8075 Present (Corresponding_Remote_Type (Btyp)))
8076 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8077 or else Ekind (Btyp)
8078 = E_Anonymous_Access_Protected_Subprogram_Type
8079 or else Is_Access_Constant (Btyp)
8080 or else Is_Variable (P)
8081 or else Attr_Id = Attribute_Unrestricted_Access)
8083 if Is_Entity_Name (P)
8084 and then Is_Type (Entity (P))
8086 -- Legality of a self-reference through an access
8087 -- attribute has been verified in Analyze_Access_Attribute.
8091 elsif Comes_From_Source (N) then
8092 Error_Msg_F ("access-to-variable designates constant", P);
8096 Des_Btyp := Designated_Type (Btyp);
8098 if Ada_Version >= Ada_2005
8099 and then Is_Incomplete_Type (Des_Btyp)
8101 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
8102 -- imported entity, and the non-limited view is visible, make
8103 -- use of it. If it is an incomplete subtype, use the base type
8106 if From_With_Type (Des_Btyp)
8107 and then Present (Non_Limited_View (Des_Btyp))
8109 Des_Btyp := Non_Limited_View (Des_Btyp);
8111 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
8112 Des_Btyp := Etype (Des_Btyp);
8116 if (Attr_Id = Attribute_Access
8118 Attr_Id = Attribute_Unchecked_Access)
8119 and then (Ekind (Btyp) = E_General_Access_Type
8120 or else Ekind (Btyp) = E_Anonymous_Access_Type)
8122 -- Ada 2005 (AI-230): Check the accessibility of anonymous
8123 -- access types for stand-alone objects, record and array
8124 -- components, and return objects. For a component definition
8125 -- the level is the same of the enclosing composite type.
8127 if Ada_Version >= Ada_2005
8128 and then Is_Local_Anonymous_Access (Btyp)
8129 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8130 and then Attr_Id = Attribute_Access
8132 -- In an instance, this is a runtime check, but one we
8133 -- know will fail, so generate an appropriate warning.
8135 if In_Instance_Body then
8137 ("?non-local pointer cannot point to local object", P);
8139 ("\?Program_Error will be raised at run time", P);
8141 Make_Raise_Program_Error (Loc,
8142 Reason => PE_Accessibility_Check_Failed));
8147 ("non-local pointer cannot point to local object", P);
8151 if Is_Dependent_Component_Of_Mutable_Object (P) then
8153 ("illegal attribute for discriminant-dependent component",
8157 -- Check static matching rule of 3.10.2(27). Nominal subtype
8158 -- of the prefix must statically match the designated type.
8160 Nom_Subt := Etype (P);
8162 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
8163 Nom_Subt := Base_Type (Nom_Subt);
8166 if Is_Tagged_Type (Designated_Type (Typ)) then
8168 -- If the attribute is in the context of an access
8169 -- parameter, then the prefix is allowed to be of the
8170 -- class-wide type (by AI-127).
8172 if Ekind (Typ) = E_Anonymous_Access_Type then
8173 if not Covers (Designated_Type (Typ), Nom_Subt)
8174 and then not Covers (Nom_Subt, Designated_Type (Typ))
8180 Desig := Designated_Type (Typ);
8182 if Is_Class_Wide_Type (Desig) then
8183 Desig := Etype (Desig);
8186 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8191 ("type of prefix: & not compatible",
8194 ("\with &, the expected designated type",
8195 P, Designated_Type (Typ));
8200 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8202 (not Is_Class_Wide_Type (Designated_Type (Typ))
8203 and then Is_Class_Wide_Type (Nom_Subt))
8206 ("type of prefix: & is not covered", P, Nom_Subt);
8208 ("\by &, the expected designated type" &
8209 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8212 if Is_Class_Wide_Type (Designated_Type (Typ))
8213 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8214 and then Is_Constrained (Etype (Designated_Type (Typ)))
8215 and then Designated_Type (Typ) /= Nom_Subt
8217 Apply_Discriminant_Check
8218 (N, Etype (Designated_Type (Typ)));
8221 -- Ada 2005 (AI-363): Require static matching when designated
8222 -- type has discriminants and a constrained partial view, since
8223 -- in general objects of such types are mutable, so we can't
8224 -- allow the access value to designate a constrained object
8225 -- (because access values must be assumed to designate mutable
8226 -- objects when designated type does not impose a constraint).
8228 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8231 elsif Has_Discriminants (Designated_Type (Typ))
8232 and then not Is_Constrained (Des_Btyp)
8234 (Ada_Version < Ada_2005
8236 not Has_Constrained_Partial_View
8237 (Designated_Type (Base_Type (Typ))))
8243 ("object subtype must statically match "
8244 & "designated subtype", P);
8246 if Is_Entity_Name (P)
8247 and then Is_Array_Type (Designated_Type (Typ))
8250 D : constant Node_Id := Declaration_Node (Entity (P));
8253 Error_Msg_N ("aliased object has explicit bounds?",
8255 Error_Msg_N ("\declare without bounds"
8256 & " (and with explicit initialization)?", D);
8257 Error_Msg_N ("\for use with unconstrained access?", D);
8262 -- Check the static accessibility rule of 3.10.2(28).
8263 -- Note that this check is not performed for the
8264 -- case of an anonymous access type, since the access
8265 -- attribute is always legal in such a context.
8267 if Attr_Id /= Attribute_Unchecked_Access
8268 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8269 and then Ekind (Btyp) = E_General_Access_Type
8271 Accessibility_Message;
8276 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
8277 E_Anonymous_Access_Protected_Subprogram_Type)
8279 if Is_Entity_Name (P)
8280 and then not Is_Protected_Type (Scope (Entity (P)))
8282 Error_Msg_F ("context requires a protected subprogram", P);
8284 -- Check accessibility of protected object against that of the
8285 -- access type, but only on user code, because the expander
8286 -- creates access references for handlers. If the context is an
8287 -- anonymous_access_to_protected, there are no accessibility
8288 -- checks either. Omit check entirely for Unrestricted_Access.
8290 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8291 and then Comes_From_Source (N)
8292 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8293 and then Attr_Id /= Attribute_Unrestricted_Access
8295 Accessibility_Message;
8299 elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
8300 E_Anonymous_Access_Subprogram_Type)
8301 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8303 Error_Msg_F ("context requires a non-protected subprogram", P);
8306 -- The context cannot be a pool-specific type, but this is a
8307 -- legality rule, not a resolution rule, so it must be checked
8308 -- separately, after possibly disambiguation (see AI-245).
8310 if Ekind (Btyp) = E_Access_Type
8311 and then Attr_Id /= Attribute_Unrestricted_Access
8313 Wrong_Type (N, Typ);
8316 -- The context may be a constrained access type (however ill-
8317 -- advised such subtypes might be) so in order to generate a
8318 -- constraint check when needed set the type of the attribute
8319 -- reference to the base type of the context.
8321 Set_Etype (N, Btyp);
8323 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8325 if Attr_Id /= Attribute_Unrestricted_Access then
8326 if Is_Atomic_Object (P)
8327 and then not Is_Atomic (Designated_Type (Typ))
8330 ("access to atomic object cannot yield access-to-" &
8331 "non-atomic type", P);
8333 elsif Is_Volatile_Object (P)
8334 and then not Is_Volatile (Designated_Type (Typ))
8337 ("access to volatile object cannot yield access-to-" &
8338 "non-volatile type", P);
8342 if Is_Entity_Name (P) then
8343 Set_Address_Taken (Entity (P));
8345 end Access_Attribute;
8351 -- Deal with resolving the type for Address attribute, overloading
8352 -- is not permitted here, since there is no context to resolve it.
8354 when Attribute_Address | Attribute_Code_Address =>
8355 Address_Attribute : begin
8357 -- To be safe, assume that if the address of a variable is taken,
8358 -- it may be modified via this address, so note modification.
8360 if Is_Variable (P) then
8361 Note_Possible_Modification (P, Sure => False);
8364 if Nkind (P) in N_Subexpr
8365 and then Is_Overloaded (P)
8367 Get_First_Interp (P, Index, It);
8368 Get_Next_Interp (Index, It);
8370 if Present (It.Nam) then
8371 Error_Msg_Name_1 := Aname;
8373 ("prefix of % attribute cannot be overloaded", P);
8377 if not Is_Entity_Name (P)
8378 or else not Is_Overloadable (Entity (P))
8380 if not Is_Task_Type (Etype (P))
8381 or else Nkind (P) = N_Explicit_Dereference
8387 -- If this is the name of a derived subprogram, or that of a
8388 -- generic actual, the address is that of the original entity.
8390 if Is_Entity_Name (P)
8391 and then Is_Overloadable (Entity (P))
8392 and then Present (Alias (Entity (P)))
8395 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8398 if Is_Entity_Name (P) then
8399 Set_Address_Taken (Entity (P));
8402 if Nkind (P) = N_Slice then
8404 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8405 -- even if the array is packed and the slice itself is not
8406 -- addressable. Transform the prefix into an indexed component.
8408 -- Note that the transformation is safe only if we know that
8409 -- the slice is non-null. That is because a null slice can have
8410 -- an out of bounds index value.
8412 -- Right now, gigi blows up if given 'Address on a slice as a
8413 -- result of some incorrect freeze nodes generated by the front
8414 -- end, and this covers up that bug in one case, but the bug is
8415 -- likely still there in the cases not handled by this code ???
8417 -- It's not clear what 'Address *should* return for a null
8418 -- slice with out of bounds indexes, this might be worth an ARG
8421 -- One approach would be to do a length check unconditionally,
8422 -- and then do the transformation below unconditionally, but
8423 -- analyze with checks off, avoiding the problem of the out of
8424 -- bounds index. This approach would interpret the address of
8425 -- an out of bounds null slice as being the address where the
8426 -- array element would be if there was one, which is probably
8427 -- as reasonable an interpretation as any ???
8430 Loc : constant Source_Ptr := Sloc (P);
8431 D : constant Node_Id := Discrete_Range (P);
8435 if Is_Entity_Name (D)
8438 (Type_Low_Bound (Entity (D)),
8439 Type_High_Bound (Entity (D)))
8442 Make_Attribute_Reference (Loc,
8443 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8444 Attribute_Name => Name_First);
8446 elsif Nkind (D) = N_Range
8447 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8449 Lo := Low_Bound (D);
8455 if Present (Lo) then
8457 Make_Indexed_Component (Loc,
8458 Prefix => Relocate_Node (Prefix (P)),
8459 Expressions => New_List (Lo)));
8461 Analyze_And_Resolve (P);
8465 end Address_Attribute;
8471 -- Prefix of the AST_Entry attribute is an entry name which must
8472 -- not be resolved, since this is definitely not an entry call.
8474 when Attribute_AST_Entry =>
8481 -- Prefix of Body_Version attribute can be a subprogram name which
8482 -- must not be resolved, since this is not a call.
8484 when Attribute_Body_Version =>
8491 -- Prefix of Caller attribute is an entry name which must not
8492 -- be resolved, since this is definitely not an entry call.
8494 when Attribute_Caller =>
8501 -- Shares processing with Address attribute
8507 -- If the prefix of the Count attribute is an entry name it must not
8508 -- be resolved, since this is definitely not an entry call. However,
8509 -- if it is an element of an entry family, the index itself may
8510 -- have to be resolved because it can be a general expression.
8512 when Attribute_Count =>
8513 if Nkind (P) = N_Indexed_Component
8514 and then Is_Entity_Name (Prefix (P))
8517 Indx : constant Node_Id := First (Expressions (P));
8518 Fam : constant Entity_Id := Entity (Prefix (P));
8520 Resolve (Indx, Entry_Index_Type (Fam));
8521 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8529 -- Prefix of the Elaborated attribute is a subprogram name which
8530 -- must not be resolved, since this is definitely not a call. Note
8531 -- that it is a library unit, so it cannot be overloaded here.
8533 when Attribute_Elaborated =>
8540 -- Prefix of Enabled attribute is a check name, which must be treated
8541 -- specially and not touched by Resolve.
8543 when Attribute_Enabled =>
8546 --------------------
8547 -- Mechanism_Code --
8548 --------------------
8550 -- Prefix of the Mechanism_Code attribute is a function name
8551 -- which must not be resolved. Should we check for overloaded ???
8553 when Attribute_Mechanism_Code =>
8560 -- Most processing is done in sem_dist, after determining the
8561 -- context type. Node is rewritten as a conversion to a runtime call.
8563 when Attribute_Partition_ID =>
8564 Process_Partition_Id (N);
8571 when Attribute_Pool_Address =>
8578 -- We replace the Range attribute node with a range expression whose
8579 -- bounds are the 'First and 'Last attributes applied to the same
8580 -- prefix. The reason that we do this transformation here instead of
8581 -- in the expander is that it simplifies other parts of the semantic
8582 -- analysis which assume that the Range has been replaced; thus it
8583 -- must be done even when in semantic-only mode (note that the RM
8584 -- specifically mentions this equivalence, we take care that the
8585 -- prefix is only evaluated once).
8587 when Attribute_Range => Range_Attribute :
8593 if not Is_Entity_Name (P)
8594 or else not Is_Type (Entity (P))
8600 Make_Attribute_Reference (Loc,
8602 Duplicate_Subexpr (P, Name_Req => True),
8603 Attribute_Name => Name_Last,
8604 Expressions => Expressions (N));
8607 Make_Attribute_Reference (Loc,
8609 Attribute_Name => Name_First,
8610 Expressions => Expressions (N));
8612 -- If the original was marked as Must_Not_Freeze (see code
8613 -- in Sem_Ch3.Make_Index), then make sure the rewriting
8614 -- does not freeze either.
8616 if Must_Not_Freeze (N) then
8617 Set_Must_Not_Freeze (HB);
8618 Set_Must_Not_Freeze (LB);
8619 Set_Must_Not_Freeze (Prefix (HB));
8620 Set_Must_Not_Freeze (Prefix (LB));
8623 if Raises_Constraint_Error (Prefix (N)) then
8625 -- Preserve Sloc of prefix in the new bounds, so that
8626 -- the posted warning can be removed if we are within
8627 -- unreachable code.
8629 Set_Sloc (LB, Sloc (Prefix (N)));
8630 Set_Sloc (HB, Sloc (Prefix (N)));
8633 Rewrite (N, Make_Range (Loc, LB, HB));
8634 Analyze_And_Resolve (N, Typ);
8636 -- Ensure that the expanded range does not have side effects
8638 Force_Evaluation (LB);
8639 Force_Evaluation (HB);
8641 -- Normally after resolving attribute nodes, Eval_Attribute
8642 -- is called to do any possible static evaluation of the node.
8643 -- However, here since the Range attribute has just been
8644 -- transformed into a range expression it is no longer an
8645 -- attribute node and therefore the call needs to be avoided
8646 -- and is accomplished by simply returning from the procedure.
8649 end Range_Attribute;
8655 -- We will only come here during the prescan of a spec expression
8656 -- containing a Result attribute. In that case the proper Etype has
8657 -- already been set, and nothing more needs to be done here.
8659 when Attribute_Result =>
8666 -- Prefix must not be resolved in this case, since it is not a
8667 -- real entity reference. No action of any kind is require!
8669 when Attribute_UET_Address =>
8672 ----------------------
8673 -- Unchecked_Access --
8674 ----------------------
8676 -- Processing is shared with Access
8678 -------------------------
8679 -- Unrestricted_Access --
8680 -------------------------
8682 -- Processing is shared with Access
8688 -- Apply range check. Note that we did not do this during the
8689 -- analysis phase, since we wanted Eval_Attribute to have a
8690 -- chance at finding an illegal out of range value.
8692 when Attribute_Val =>
8694 -- Note that we do our own Eval_Attribute call here rather than
8695 -- use the common one, because we need to do processing after
8696 -- the call, as per above comment.
8700 -- Eval_Attribute may replace the node with a raise CE, or
8701 -- fold it to a constant. Obviously we only apply a scalar
8702 -- range check if this did not happen!
8704 if Nkind (N) = N_Attribute_Reference
8705 and then Attribute_Name (N) = Name_Val
8707 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
8716 -- Prefix of Version attribute can be a subprogram name which
8717 -- must not be resolved, since this is not a call.
8719 when Attribute_Version =>
8722 ----------------------
8723 -- Other Attributes --
8724 ----------------------
8726 -- For other attributes, resolve prefix unless it is a type. If
8727 -- the attribute reference itself is a type name ('Base and 'Class)
8728 -- then this is only legal within a task or protected record.
8731 if not Is_Entity_Name (P)
8732 or else not Is_Type (Entity (P))
8737 -- If the attribute reference itself is a type name ('Base,
8738 -- 'Class) then this is only legal within a task or protected
8739 -- record. What is this all about ???
8741 if Is_Entity_Name (N)
8742 and then Is_Type (Entity (N))
8744 if Is_Concurrent_Type (Entity (N))
8745 and then In_Open_Scopes (Entity (P))
8750 ("invalid use of subtype name in expression or call", N);
8754 -- For attributes whose argument may be a string, complete
8755 -- resolution of argument now. This avoids premature expansion
8756 -- (and the creation of transient scopes) before the attribute
8757 -- reference is resolved.
8760 when Attribute_Value =>
8761 Resolve (First (Expressions (N)), Standard_String);
8763 when Attribute_Wide_Value =>
8764 Resolve (First (Expressions (N)), Standard_Wide_String);
8766 when Attribute_Wide_Wide_Value =>
8767 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
8769 when others => null;
8772 -- If the prefix of the attribute is a class-wide type then it
8773 -- will be expanded into a dispatching call to a predefined
8774 -- primitive. Therefore we must check for potential violation
8775 -- of such restriction.
8777 if Is_Class_Wide_Type (Etype (P)) then
8778 Check_Restriction (No_Dispatching_Calls, N);
8782 -- Normally the Freezing is done by Resolve but sometimes the Prefix
8783 -- is not resolved, in which case the freezing must be done now.
8785 Freeze_Expression (P);
8787 -- Finally perform static evaluation on the attribute reference
8790 end Resolve_Attribute;
8792 --------------------------------
8793 -- Stream_Attribute_Available --
8794 --------------------------------
8796 function Stream_Attribute_Available
8798 Nam : TSS_Name_Type;
8799 Partial_View : Node_Id := Empty) return Boolean
8801 Etyp : Entity_Id := Typ;
8803 -- Start of processing for Stream_Attribute_Available
8806 -- We need some comments in this body ???
8808 if Has_Stream_Attribute_Definition (Typ, Nam) then
8812 if Is_Class_Wide_Type (Typ) then
8813 return not Is_Limited_Type (Typ)
8814 or else Stream_Attribute_Available (Etype (Typ), Nam);
8817 if Nam = TSS_Stream_Input
8818 and then Is_Abstract_Type (Typ)
8819 and then not Is_Class_Wide_Type (Typ)
8824 if not (Is_Limited_Type (Typ)
8825 or else (Present (Partial_View)
8826 and then Is_Limited_Type (Partial_View)))
8831 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
8833 if Nam = TSS_Stream_Input
8834 and then Ada_Version >= Ada_2005
8835 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
8839 elsif Nam = TSS_Stream_Output
8840 and then Ada_Version >= Ada_2005
8841 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
8846 -- Case of Read and Write: check for attribute definition clause that
8847 -- applies to an ancestor type.
8849 while Etype (Etyp) /= Etyp loop
8850 Etyp := Etype (Etyp);
8852 if Has_Stream_Attribute_Definition (Etyp, Nam) then
8857 if Ada_Version < Ada_2005 then
8859 -- In Ada 95 mode, also consider a non-visible definition
8862 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
8865 and then Stream_Attribute_Available
8866 (Btyp, Nam, Partial_View => Typ);
8871 end Stream_Attribute_Available;