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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ A T T R --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2018, Free Software Foundation, Inc. --
10 -- --
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. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
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 Debug; use Debug;
32 with Einfo; use Einfo;
33 with Elists; use Elists;
34 with Errout; use Errout;
35 with Eval_Fat;
36 with Exp_Dist; use Exp_Dist;
37 with Exp_Util; use Exp_Util;
38 with Expander; use Expander;
39 with Freeze; use Freeze;
40 with Gnatvsn; use Gnatvsn;
41 with Itypes; use Itypes;
42 with Lib; use Lib;
43 with Lib.Xref; use Lib.Xref;
44 with Nlists; use Nlists;
45 with Nmake; use Nmake;
46 with Opt; use Opt;
47 with Restrict; use Restrict;
48 with Rident; use Rident;
49 with Rtsfind; use Rtsfind;
50 with Sdefault;
51 with Sem; use Sem;
52 with Sem_Aux; use Sem_Aux;
53 with Sem_Cat; use Sem_Cat;
54 with Sem_Ch6; use Sem_Ch6;
55 with Sem_Ch8; use Sem_Ch8;
56 with Sem_Ch10; use Sem_Ch10;
57 with Sem_Dim; use Sem_Dim;
58 with Sem_Dist; use Sem_Dist;
59 with Sem_Elab; use Sem_Elab;
60 with Sem_Elim; use Sem_Elim;
61 with Sem_Eval; use Sem_Eval;
62 with Sem_Prag; use Sem_Prag;
63 with Sem_Res; use Sem_Res;
64 with Sem_Type; use Sem_Type;
65 with Sem_Util; use Sem_Util;
66 with Sem_Warn;
67 with Stand; use Stand;
68 with Sinfo; use Sinfo;
69 with Sinput; use Sinput;
70 with System;
71 with Stringt; use Stringt;
72 with Style;
73 with Stylesw; use Stylesw;
74 with Targparm; use Targparm;
75 with Ttypes; use Ttypes;
76 with Tbuild; use Tbuild;
77 with Uintp; use Uintp;
78 with Uname; use Uname;
79 with Urealp; use Urealp;
81 with System.CRC32; use System.CRC32;
83 package body Sem_Attr is
85 True_Value : constant Uint := Uint_1;
86 False_Value : constant Uint := Uint_0;
87 -- Synonyms to be used when these constants are used as Boolean values
89 Bad_Attribute : exception;
90 -- Exception raised if an error is detected during attribute processing,
91 -- used so that we can abandon the processing so we don't run into
92 -- trouble with cascaded errors.
94 -- The following array is the list of attributes defined in the Ada 83 RM.
95 -- In Ada 83 mode, these are the only recognized attributes. In other Ada
96 -- modes all these attributes are recognized, even if removed in Ada 95.
98 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
99 Attribute_Address |
100 Attribute_Aft |
101 Attribute_Alignment |
102 Attribute_Base |
103 Attribute_Callable |
104 Attribute_Constrained |
105 Attribute_Count |
106 Attribute_Delta |
107 Attribute_Digits |
108 Attribute_Emax |
109 Attribute_Epsilon |
110 Attribute_First |
111 Attribute_First_Bit |
112 Attribute_Fore |
113 Attribute_Image |
114 Attribute_Large |
115 Attribute_Last |
116 Attribute_Last_Bit |
117 Attribute_Leading_Part |
118 Attribute_Length |
119 Attribute_Machine_Emax |
120 Attribute_Machine_Emin |
121 Attribute_Machine_Mantissa |
122 Attribute_Machine_Overflows |
123 Attribute_Machine_Radix |
124 Attribute_Machine_Rounds |
125 Attribute_Mantissa |
126 Attribute_Pos |
127 Attribute_Position |
128 Attribute_Pred |
129 Attribute_Range |
130 Attribute_Safe_Emax |
131 Attribute_Safe_Large |
132 Attribute_Safe_Small |
133 Attribute_Size |
134 Attribute_Small |
135 Attribute_Storage_Size |
136 Attribute_Succ |
137 Attribute_Terminated |
138 Attribute_Val |
139 Attribute_Value |
140 Attribute_Width => True,
141 others => False);
143 -- The following array is the list of attributes defined in the Ada 2005
144 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
145 -- but in Ada 95 they are considered to be implementation defined.
147 Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'(
148 Attribute_Machine_Rounding |
149 Attribute_Mod |
150 Attribute_Priority |
151 Attribute_Stream_Size |
152 Attribute_Wide_Wide_Width => True,
153 others => False);
155 -- The following array is the list of attributes defined in the Ada 2012
156 -- RM which are not defined in Ada 2005. These are recognized in Ada 95
157 -- and Ada 2005 modes, but are considered to be implementation defined.
159 Attribute_12 : constant Attribute_Class_Array := Attribute_Class_Array'(
160 Attribute_First_Valid |
161 Attribute_Has_Same_Storage |
162 Attribute_Last_Valid |
163 Attribute_Max_Alignment_For_Allocation => True,
164 others => False);
166 -- The following array contains all attributes that imply a modification
167 -- of their prefixes or result in an access value. Such prefixes can be
168 -- considered as lvalues.
170 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
171 Attribute_Class_Array'(
172 Attribute_Access |
173 Attribute_Address |
174 Attribute_Input |
175 Attribute_Read |
176 Attribute_Unchecked_Access |
177 Attribute_Unrestricted_Access => True,
178 others => False);
180 -----------------------
181 -- Local_Subprograms --
182 -----------------------
184 procedure Eval_Attribute (N : Node_Id);
185 -- Performs compile time evaluation of attributes where possible, leaving
186 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
187 -- set, and replacing the node with a literal node if the value can be
188 -- computed at compile time. All static attribute references are folded,
189 -- as well as a number of cases of non-static attributes that can always
190 -- be computed at compile time (e.g. floating-point model attributes that
191 -- are applied to non-static subtypes). Of course in such cases, the
192 -- Is_Static_Expression flag will not be set on the resulting literal.
193 -- Note that the only required action of this procedure is to catch the
194 -- static expression cases as described in the RM. Folding of other cases
195 -- is done where convenient, but some additional non-static folding is in
196 -- Expand_N_Attribute_Reference in cases where this is more convenient.
198 function Is_Anonymous_Tagged_Base
199 (Anon : Entity_Id;
200 Typ : Entity_Id) return Boolean;
201 -- For derived tagged types that constrain parent discriminants we build
202 -- an anonymous unconstrained base type. We need to recognize the relation
203 -- between the two when analyzing an access attribute for a constrained
204 -- component, before the full declaration for Typ has been analyzed, and
205 -- where therefore the prefix of the attribute does not match the enclosing
206 -- scope.
208 procedure Set_Boolean_Result (N : Node_Id; B : Boolean);
209 -- Rewrites node N with an occurrence of either Standard_False or
210 -- Standard_True, depending on the value of the parameter B. The
211 -- result is marked as a static expression.
213 function Statically_Denotes_Object (N : Node_Id) return Boolean;
214 -- Predicate used to check the legality of the prefix to 'Loop_Entry and
215 -- 'Old, when the prefix is not an entity name. Current RM specfies that
216 -- the prefix must be a direct or expanded name, but it has been proposed
217 -- that the prefix be allowed to be a selected component that does not
218 -- depend on a discriminant, or an indexed component with static indices.
219 -- Current code for this predicate implements this more permissive
220 -- implementation.
222 -----------------------
223 -- Analyze_Attribute --
224 -----------------------
226 procedure Analyze_Attribute (N : Node_Id) is
227 Loc : constant Source_Ptr := Sloc (N);
228 Aname : constant Name_Id := Attribute_Name (N);
229 P : constant Node_Id := Prefix (N);
230 Exprs : constant List_Id := Expressions (N);
231 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
232 E1 : Node_Id;
233 E2 : Node_Id;
235 P_Type : Entity_Id := Empty;
236 -- Type of prefix after analysis
238 P_Base_Type : Entity_Id := Empty;
239 -- Base type of prefix after analysis
241 -----------------------
242 -- Local Subprograms --
243 -----------------------
245 procedure Address_Checks;
246 -- Semantic checks for valid use of Address attribute. This was made
247 -- a separate routine with the idea of using it for unrestricted access
248 -- which seems like it should follow the same rules, but that turned
249 -- out to be impractical. So now this is only used for Address.
251 procedure Analyze_Access_Attribute;
252 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
253 -- Internally, Id distinguishes which of the three cases is involved.
255 procedure Analyze_Attribute_Old_Result
256 (Legal : out Boolean;
257 Spec_Id : out Entity_Id);
258 -- Common processing for attributes 'Old and 'Result. The routine checks
259 -- that the attribute appears in a postcondition-like aspect or pragma
260 -- associated with a suitable subprogram or a body. Flag Legal is set
261 -- when the above criteria are met. Spec_Id denotes the entity of the
262 -- subprogram [body] or Empty if the attribute is illegal.
264 procedure Analyze_Image_Attribute (Str_Typ : Entity_Id);
265 -- Common processing for attributes 'Img, 'Image, 'Wide_Image, and
266 -- 'Wide_Wide_Image. The routine checks that the prefix is valid and
267 -- sets the type of the attribute to the one specified by Str_Typ (e.g.
268 -- Standard_String for 'Image and Standard_Wide_String for 'Wide_Image).
270 procedure Bad_Attribute_For_Predicate;
271 -- Output error message for use of a predicate (First, Last, Range) not
272 -- allowed with a type that has predicates. If the type is a generic
273 -- actual, then the message is a warning, and we generate code to raise
274 -- program error with an appropriate reason. No error message is given
275 -- for internally generated uses of the attributes. This legality rule
276 -- only applies to scalar types.
278 procedure Check_Array_Or_Scalar_Type;
279 -- Common procedure used by First, Last, Range attribute to check
280 -- that the prefix is a constrained array or scalar type, or a name
281 -- of an array object, and that an argument appears only if appropriate
282 -- (i.e. only in the array case).
284 procedure Check_Array_Type;
285 -- Common semantic checks for all array attributes. Checks that the
286 -- prefix is a constrained array type or the name of an array object.
287 -- The error message for non-arrays is specialized appropriately.
289 procedure Check_Asm_Attribute;
290 -- Common semantic checks for Asm_Input and Asm_Output attributes
292 procedure Check_Component;
293 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
294 -- Position. Checks prefix is an appropriate selected component.
296 procedure Check_Decimal_Fixed_Point_Type;
297 -- Check that prefix of attribute N is a decimal fixed-point type
299 procedure Check_Dereference;
300 -- If the prefix of attribute is an object of an access type, then
301 -- introduce an explicit dereference, and adjust P_Type accordingly.
303 procedure Check_Discrete_Type;
304 -- Verify that prefix of attribute N is a discrete type
306 procedure Check_E0;
307 -- Check that no attribute arguments are present
309 procedure Check_Either_E0_Or_E1;
310 -- Check that there are zero or one attribute arguments present
312 procedure Check_E1;
313 -- Check that exactly one attribute argument is present
315 procedure Check_E2;
316 -- Check that two attribute arguments are present
318 procedure Check_Enum_Image;
319 -- If the prefix type of 'Image is an enumeration type, set all its
320 -- literals as referenced, since the image function could possibly end
321 -- up referencing any of the literals indirectly. Same for Enum_Val.
322 -- Set the flag only if the reference is in the main code unit. Same
323 -- restriction when resolving 'Value; otherwise an improperly set
324 -- reference when analyzing an inlined body will lose a proper
325 -- warning on a useless with_clause.
327 procedure Check_First_Last_Valid;
328 -- Perform all checks for First_Valid and Last_Valid attributes
330 procedure Check_Fixed_Point_Type;
331 -- Verify that prefix of attribute N is a fixed type
333 procedure Check_Fixed_Point_Type_0;
334 -- Verify that prefix of attribute N is a fixed type and that
335 -- no attribute expressions are present.
337 procedure Check_Floating_Point_Type;
338 -- Verify that prefix of attribute N is a float type
340 procedure Check_Floating_Point_Type_0;
341 -- Verify that prefix of attribute N is a float type and that
342 -- no attribute expressions are present.
344 procedure Check_Floating_Point_Type_1;
345 -- Verify that prefix of attribute N is a float type and that
346 -- exactly one attribute expression is present.
348 procedure Check_Floating_Point_Type_2;
349 -- Verify that prefix of attribute N is a float type and that
350 -- two attribute expressions are present
352 procedure Check_SPARK_05_Restriction_On_Attribute;
353 -- Issue an error in formal mode because attribute N is allowed
355 procedure Check_Integer_Type;
356 -- Verify that prefix of attribute N is an integer type
358 procedure Check_Modular_Integer_Type;
359 -- Verify that prefix of attribute N is a modular integer type
361 procedure Check_Not_CPP_Type;
362 -- Check that P (the prefix of the attribute) is not an CPP type
363 -- for which no Ada predefined primitive is available.
365 procedure Check_Not_Incomplete_Type;
366 -- Check that P (the prefix of the attribute) is not an incomplete
367 -- type or a private type for which no full view has been given.
369 procedure Check_Object_Reference (P : Node_Id);
370 -- Check that P is an object reference
372 procedure Check_PolyORB_Attribute;
373 -- Validity checking for PolyORB/DSA attribute
375 procedure Check_Program_Unit;
376 -- Verify that prefix of attribute N is a program unit
378 procedure Check_Real_Type;
379 -- Verify that prefix of attribute N is fixed or float type
381 procedure Check_Scalar_Type;
382 -- Verify that prefix of attribute N is a scalar type
384 procedure Check_Standard_Prefix;
385 -- Verify that prefix of attribute N is package Standard. Also checks
386 -- that there are no arguments.
388 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
389 -- Validity checking for stream attribute. Nam is the TSS name of the
390 -- corresponding possible defined attribute function (e.g. for the
391 -- Read attribute, Nam will be TSS_Stream_Read).
393 procedure Check_System_Prefix;
394 -- Verify that prefix of attribute N is package System
396 procedure Check_Task_Prefix;
397 -- Verify that prefix of attribute N is a task or task type
399 procedure Check_Type;
400 -- Verify that the prefix of attribute N is a type
402 procedure Check_Unit_Name (Nod : Node_Id);
403 -- Check that Nod is of the form of a library unit name, i.e that
404 -- it is an identifier, or a selected component whose prefix is
405 -- itself of the form of a library unit name. Note that this is
406 -- quite different from Check_Program_Unit, since it only checks
407 -- the syntactic form of the name, not the semantic identity. This
408 -- is because it is used with attributes (Elab_Body, Elab_Spec and
409 -- Elaborated) which can refer to non-visible unit.
411 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
412 pragma No_Return (Error_Attr);
413 procedure Error_Attr;
414 pragma No_Return (Error_Attr);
415 -- Posts error using Error_Msg_N at given node, sets type of attribute
416 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
417 -- semantic processing. The message typically contains a % insertion
418 -- character which is replaced by the attribute name. The call with
419 -- no arguments is used when the caller has already generated the
420 -- required error messages.
422 procedure Error_Attr_P (Msg : String);
423 pragma No_Return (Error_Attr_P);
424 -- Like Error_Attr, but error is posted at the start of the prefix
426 procedure Legal_Formal_Attribute;
427 -- Common processing for attributes Definite and Has_Discriminants.
428 -- Checks that prefix is generic indefinite formal type.
430 procedure Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
431 -- Common processing for attributes Max_Alignment_For_Allocation and
432 -- Max_Size_In_Storage_Elements.
434 procedure Min_Max;
435 -- Common processing for attributes Max and Min
437 procedure Standard_Attribute (Val : Int);
438 -- Used to process attributes whose prefix is package Standard which
439 -- yield values of type Universal_Integer. The attribute reference
440 -- node is rewritten with an integer literal of the given value which
441 -- is marked as static.
443 procedure Uneval_Old_Msg;
444 -- Called when Loop_Entry or Old is used in a potentially unevaluated
445 -- expression. Generates appropriate message or warning depending on
446 -- the setting of Opt.Uneval_Old (or flags in an N_Aspect_Specification
447 -- node in the aspect case).
449 procedure Unexpected_Argument (En : Node_Id);
450 pragma No_Return (Unexpected_Argument);
451 -- Signal unexpected attribute argument (En is the argument), and then
452 -- raises Bad_Attribute to avoid any further semantic processing.
454 procedure Validate_Non_Static_Attribute_Function_Call;
455 -- Called when processing an attribute that is a function call to a
456 -- non-static function, i.e. an attribute function that either takes
457 -- non-scalar arguments or returns a non-scalar result. Verifies that
458 -- such a call does not appear in a preelaborable context.
460 --------------------
461 -- Address_Checks --
462 --------------------
464 procedure Address_Checks is
465 begin
466 -- An Address attribute created by expansion is legal even when it
467 -- applies to other entity-denoting expressions.
469 if not Comes_From_Source (N) then
470 return;
472 -- Address attribute on a protected object self reference is legal
474 elsif Is_Protected_Self_Reference (P) then
475 return;
477 -- Address applied to an entity
479 elsif Is_Entity_Name (P) then
480 declare
481 Ent : constant Entity_Id := Entity (P);
483 begin
484 if Is_Subprogram (Ent) then
485 Set_Address_Taken (Ent);
486 Kill_Current_Values (Ent);
488 -- An Address attribute is accepted when generated by the
489 -- compiler for dispatching operation, and an error is
490 -- issued once the subprogram is frozen (to avoid confusing
491 -- errors about implicit uses of Address in the dispatch
492 -- table initialization).
494 if Has_Pragma_Inline_Always (Entity (P))
495 and then Comes_From_Source (P)
496 then
497 Error_Attr_P
498 ("prefix of % attribute cannot be Inline_Always "
499 & "subprogram");
501 -- It is illegal to apply 'Address to an intrinsic
502 -- subprogram. This is now formalized in AI05-0095.
503 -- In an instance, an attempt to obtain 'Address of an
504 -- intrinsic subprogram (e.g the renaming of a predefined
505 -- operator that is an actual) raises Program_Error.
507 elsif Convention (Ent) = Convention_Intrinsic then
508 if In_Instance then
509 Rewrite (N,
510 Make_Raise_Program_Error (Loc,
511 Reason => PE_Address_Of_Intrinsic));
513 else
514 Error_Msg_Name_1 := Aname;
515 Error_Msg_N
516 ("cannot take % of intrinsic subprogram", N);
517 end if;
519 -- Issue an error if prefix denotes an eliminated subprogram
521 else
522 Check_For_Eliminated_Subprogram (P, Ent);
523 end if;
525 -- Object or label reference
527 elsif Is_Object (Ent) or else Ekind (Ent) = E_Label then
528 Set_Address_Taken (Ent);
530 -- Deal with No_Implicit_Aliasing restriction
532 if Restriction_Check_Required (No_Implicit_Aliasing) then
533 if not Is_Aliased_View (P) then
534 Check_Restriction (No_Implicit_Aliasing, P);
535 else
536 Check_No_Implicit_Aliasing (P);
537 end if;
538 end if;
540 -- If we have an address of an object, and the attribute
541 -- comes from source, then set the object as potentially
542 -- source modified. We do this because the resulting address
543 -- can potentially be used to modify the variable and we
544 -- might not detect this, leading to some junk warnings.
546 Set_Never_Set_In_Source (Ent, False);
548 -- Allow Address to be applied to task or protected type,
549 -- returning null address (what is that about???)
551 elsif (Is_Concurrent_Type (Etype (Ent))
552 and then Etype (Ent) = Base_Type (Ent))
553 or else Ekind (Ent) = E_Package
554 or else Is_Generic_Unit (Ent)
555 then
556 Rewrite (N,
557 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
559 -- Anything else is illegal
561 else
562 Error_Attr ("invalid prefix for % attribute", P);
563 end if;
564 end;
566 -- Object is OK
568 elsif Is_Object_Reference (P) then
569 return;
571 -- Subprogram called using dot notation
573 elsif Nkind (P) = N_Selected_Component
574 and then Is_Subprogram (Entity (Selector_Name (P)))
575 then
576 return;
578 -- What exactly are we allowing here ??? and is this properly
579 -- documented in the sinfo documentation for this node ???
581 elsif Relaxed_RM_Semantics
582 and then Nkind (P) = N_Attribute_Reference
583 then
584 return;
586 -- All other non-entity name cases are illegal
588 else
589 Error_Attr ("invalid prefix for % attribute", P);
590 end if;
591 end Address_Checks;
593 ------------------------------
594 -- Analyze_Access_Attribute --
595 ------------------------------
597 procedure Analyze_Access_Attribute is
598 Acc_Type : Entity_Id;
600 Scop : Entity_Id;
601 Typ : Entity_Id;
603 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
604 -- Build an access-to-object type whose designated type is DT,
605 -- and whose Ekind is appropriate to the attribute type. The
606 -- type that is constructed is returned as the result.
608 procedure Build_Access_Subprogram_Type (P : Node_Id);
609 -- Build an access to subprogram whose designated type is the type of
610 -- the prefix. If prefix is overloaded, so is the node itself. The
611 -- result is stored in Acc_Type.
613 function OK_Self_Reference return Boolean;
614 -- An access reference whose prefix is a type can legally appear
615 -- within an aggregate, where it is obtained by expansion of
616 -- a defaulted aggregate. The enclosing aggregate that contains
617 -- the self-referenced is flagged so that the self-reference can
618 -- be expanded into a reference to the target object (see exp_aggr).
620 ------------------------------
621 -- Build_Access_Object_Type --
622 ------------------------------
624 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
625 Typ : constant Entity_Id :=
626 New_Internal_Entity
627 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
628 begin
629 Set_Etype (Typ, Typ);
630 Set_Is_Itype (Typ);
631 Set_Associated_Node_For_Itype (Typ, N);
632 Set_Directly_Designated_Type (Typ, DT);
633 return Typ;
634 end Build_Access_Object_Type;
636 ----------------------------------
637 -- Build_Access_Subprogram_Type --
638 ----------------------------------
640 procedure Build_Access_Subprogram_Type (P : Node_Id) is
641 Index : Interp_Index;
642 It : Interp;
644 procedure Check_Local_Access (E : Entity_Id);
645 -- Deal with possible access to local subprogram. If we have such
646 -- an access, we set a flag to kill all tracked values on any call
647 -- because this access value may be passed around, and any called
648 -- code might use it to access a local procedure which clobbers a
649 -- tracked value. If the scope is a loop or block, indicate that
650 -- value tracking is disabled for the enclosing subprogram.
652 function Get_Kind (E : Entity_Id) return Entity_Kind;
653 -- Distinguish between access to regular/protected subprograms
655 ------------------------
656 -- Check_Local_Access --
657 ------------------------
659 procedure Check_Local_Access (E : Entity_Id) is
660 begin
661 if not Is_Library_Level_Entity (E) then
662 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
663 Set_Suppress_Value_Tracking_On_Call
664 (Nearest_Dynamic_Scope (Current_Scope));
665 end if;
666 end Check_Local_Access;
668 --------------
669 -- Get_Kind --
670 --------------
672 function Get_Kind (E : Entity_Id) return Entity_Kind is
673 begin
674 if Convention (E) = Convention_Protected then
675 return E_Access_Protected_Subprogram_Type;
676 else
677 return E_Access_Subprogram_Type;
678 end if;
679 end Get_Kind;
681 -- Start of processing for Build_Access_Subprogram_Type
683 begin
684 -- In the case of an access to subprogram, use the name of the
685 -- subprogram itself as the designated type. Type-checking in
686 -- this case compares the signatures of the designated types.
688 -- Note: This fragment of the tree is temporarily malformed
689 -- because the correct tree requires an E_Subprogram_Type entity
690 -- as the designated type. In most cases this designated type is
691 -- later overridden by the semantics with the type imposed by the
692 -- context during the resolution phase. In the specific case of
693 -- the expression Address!(Prim'Unrestricted_Access), used to
694 -- initialize slots of dispatch tables, this work will be done by
695 -- the expander (see Exp_Aggr).
697 -- The reason to temporarily add this kind of node to the tree
698 -- instead of a proper E_Subprogram_Type itype, is the following:
699 -- in case of errors found in the source file we report better
700 -- error messages. For example, instead of generating the
701 -- following error:
703 -- "expected access to subprogram with profile
704 -- defined at line X"
706 -- we currently generate:
708 -- "expected access to function Z defined at line X"
710 Set_Etype (N, Any_Type);
712 if not Is_Overloaded (P) then
713 Check_Local_Access (Entity (P));
715 if not Is_Intrinsic_Subprogram (Entity (P)) then
716 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
717 Set_Is_Public (Acc_Type, False);
718 Set_Etype (Acc_Type, Acc_Type);
719 Set_Convention (Acc_Type, Convention (Entity (P)));
720 Set_Directly_Designated_Type (Acc_Type, Entity (P));
721 Set_Etype (N, Acc_Type);
722 Freeze_Before (N, Acc_Type);
723 end if;
725 else
726 Get_First_Interp (P, Index, It);
727 while Present (It.Nam) loop
728 Check_Local_Access (It.Nam);
730 if not Is_Intrinsic_Subprogram (It.Nam) then
731 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
732 Set_Is_Public (Acc_Type, False);
733 Set_Etype (Acc_Type, Acc_Type);
734 Set_Convention (Acc_Type, Convention (It.Nam));
735 Set_Directly_Designated_Type (Acc_Type, It.Nam);
736 Add_One_Interp (N, Acc_Type, Acc_Type);
737 Freeze_Before (N, Acc_Type);
738 end if;
740 Get_Next_Interp (Index, It);
741 end loop;
742 end if;
744 -- Cannot be applied to intrinsic. Looking at the tests above,
745 -- the only way Etype (N) can still be set to Any_Type is if
746 -- Is_Intrinsic_Subprogram was True for some referenced entity.
748 if Etype (N) = Any_Type then
749 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
750 end if;
751 end Build_Access_Subprogram_Type;
753 ----------------------
754 -- OK_Self_Reference --
755 ----------------------
757 function OK_Self_Reference return Boolean is
758 Par : Node_Id;
760 begin
761 Par := Parent (N);
762 while Present (Par)
763 and then
764 (Nkind (Par) = N_Component_Association
765 or else Nkind (Par) in N_Subexpr)
766 loop
767 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
768 if Etype (Par) = Typ then
769 Set_Has_Self_Reference (Par);
771 -- Check the context: the aggregate must be part of the
772 -- initialization of a type or component, or it is the
773 -- resulting expansion in an initialization procedure.
775 if Is_Init_Proc (Current_Scope) then
776 return True;
777 else
778 Par := Parent (Par);
779 while Present (Par) loop
780 if Nkind (Par) = N_Full_Type_Declaration then
781 return True;
782 end if;
784 Par := Parent (Par);
785 end loop;
786 end if;
788 return False;
789 end if;
790 end if;
792 Par := Parent (Par);
793 end loop;
795 -- No enclosing aggregate, or not a self-reference
797 return False;
798 end OK_Self_Reference;
800 -- Start of processing for Analyze_Access_Attribute
802 begin
803 Check_SPARK_05_Restriction_On_Attribute;
804 Check_E0;
806 if Nkind (P) = N_Character_Literal then
807 Error_Attr_P
808 ("prefix of % attribute cannot be enumeration literal");
809 end if;
811 -- Preserve relevant elaboration-related attributes of the context
812 -- which are no longer available or very expensive to recompute once
813 -- analysis, resolution, and expansion are over.
815 Mark_Elaboration_Attributes
816 (N_Id => N,
817 Checks => True,
818 Modes => True);
820 -- Save the scenario for later examination by the ABE Processing
821 -- phase.
823 Record_Elaboration_Scenario (N);
825 -- Case of access to subprogram
827 if Is_Entity_Name (P) and then Is_Overloadable (Entity (P)) then
828 if Has_Pragma_Inline_Always (Entity (P)) then
829 Error_Attr_P
830 ("prefix of % attribute cannot be Inline_Always subprogram");
832 elsif Aname = Name_Unchecked_Access then
833 Error_Attr ("attribute% cannot be applied to a subprogram", P);
834 end if;
836 -- Issue an error if the prefix denotes an eliminated subprogram
838 Check_For_Eliminated_Subprogram (P, Entity (P));
840 -- Check for obsolescent subprogram reference
842 Check_Obsolescent_2005_Entity (Entity (P), P);
844 -- Build the appropriate subprogram type
846 Build_Access_Subprogram_Type (P);
848 -- For P'Access or P'Unrestricted_Access, where P is a nested
849 -- subprogram, we might be passing P to another subprogram (but we
850 -- don't check that here), which might call P. P could modify
851 -- local variables, so we need to kill current values. It is
852 -- important not to do this for library-level subprograms, because
853 -- Kill_Current_Values is very inefficient in the case of library
854 -- level packages with lots of tagged types.
856 if Is_Library_Level_Entity (Entity (Prefix (N))) then
857 null;
859 -- Do not kill values on nodes initializing dispatch tables
860 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
861 -- is currently generated by the expander only for this
862 -- purpose. Done to keep the quality of warnings currently
863 -- generated by the compiler (otherwise any declaration of
864 -- a tagged type cleans constant indications from its scope).
866 elsif Nkind (Parent (N)) = N_Unchecked_Type_Conversion
867 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
868 or else
869 Etype (Parent (N)) = RTE (RE_Size_Ptr))
870 and then Is_Dispatching_Operation
871 (Directly_Designated_Type (Etype (N)))
872 then
873 null;
875 else
876 Kill_Current_Values;
877 end if;
879 -- In the static elaboration model, treat the attribute reference
880 -- as a subprogram call for elaboration purposes. Suppress this
881 -- treatment under debug flag. In any case, we are all done.
883 if Legacy_Elaboration_Checks
884 and not Dynamic_Elaboration_Checks
885 and not Debug_Flag_Dot_UU
886 then
887 Check_Elab_Call (N);
888 end if;
890 return;
892 -- Component is an operation of a protected type
894 elsif Nkind (P) = N_Selected_Component
895 and then Is_Overloadable (Entity (Selector_Name (P)))
896 then
897 if Ekind (Entity (Selector_Name (P))) = E_Entry then
898 Error_Attr_P ("prefix of % attribute must be subprogram");
899 end if;
901 Build_Access_Subprogram_Type (Selector_Name (P));
902 return;
903 end if;
905 -- Deal with incorrect reference to a type, but note that some
906 -- accesses are allowed: references to the current type instance,
907 -- or in Ada 2005 self-referential pointer in a default-initialized
908 -- aggregate.
910 if Is_Entity_Name (P) then
911 Typ := Entity (P);
913 -- The reference may appear in an aggregate that has been expanded
914 -- into a loop. Locate scope of type definition, if any.
916 Scop := Current_Scope;
917 while Ekind (Scop) = E_Loop loop
918 Scop := Scope (Scop);
919 end loop;
921 if Is_Type (Typ) then
923 -- OK if we are within the scope of a limited type
924 -- let's mark the component as having per object constraint
926 if Is_Anonymous_Tagged_Base (Scop, Typ) then
927 Typ := Scop;
928 Set_Entity (P, Typ);
929 Set_Etype (P, Typ);
930 end if;
932 if Typ = Scop then
933 declare
934 Q : Node_Id := Parent (N);
936 begin
937 while Present (Q)
938 and then Nkind (Q) /= N_Component_Declaration
939 loop
940 Q := Parent (Q);
941 end loop;
943 if Present (Q) then
944 Set_Has_Per_Object_Constraint
945 (Defining_Identifier (Q), True);
946 end if;
947 end;
949 if Nkind (P) = N_Expanded_Name then
950 Error_Msg_F
951 ("current instance prefix must be a direct name", P);
952 end if;
954 -- If a current instance attribute appears in a component
955 -- constraint it must appear alone; other contexts (spec-
956 -- expressions, within a task body) are not subject to this
957 -- restriction.
959 if not In_Spec_Expression
960 and then not Has_Completion (Scop)
961 and then not
962 Nkind_In (Parent (N), N_Discriminant_Association,
963 N_Index_Or_Discriminant_Constraint)
964 then
965 Error_Msg_N
966 ("current instance attribute must appear alone", N);
967 end if;
969 if Is_CPP_Class (Root_Type (Typ)) then
970 Error_Msg_N
971 ("??current instance unsupported for derivations of "
972 & "'C'P'P types", N);
973 end if;
975 -- OK if we are in initialization procedure for the type
976 -- in question, in which case the reference to the type
977 -- is rewritten as a reference to the current object.
979 elsif Ekind (Scop) = E_Procedure
980 and then Is_Init_Proc (Scop)
981 and then Etype (First_Formal (Scop)) = Typ
982 then
983 Rewrite (N,
984 Make_Attribute_Reference (Loc,
985 Prefix => Make_Identifier (Loc, Name_uInit),
986 Attribute_Name => Name_Unrestricted_Access));
987 Analyze (N);
988 return;
990 -- OK if a task type, this test needs sharpening up ???
992 elsif Is_Task_Type (Typ) then
993 null;
995 -- OK if self-reference in an aggregate in Ada 2005, and
996 -- the reference comes from a copied default expression.
998 -- Note that we check legality of self-reference even if the
999 -- expression comes from source, e.g. when a single component
1000 -- association in an aggregate has a box association.
1002 elsif Ada_Version >= Ada_2005
1003 and then OK_Self_Reference
1004 then
1005 null;
1007 -- OK if reference to current instance of a protected object
1009 elsif Is_Protected_Self_Reference (P) then
1010 null;
1012 -- Otherwise we have an error case
1014 else
1015 Error_Attr ("% attribute cannot be applied to type", P);
1016 return;
1017 end if;
1018 end if;
1019 end if;
1021 -- If we fall through, we have a normal access to object case
1023 -- Unrestricted_Access is (for now) legal wherever an allocator would
1024 -- be legal, so its Etype is set to E_Allocator. The expected type
1025 -- of the other attributes is a general access type, and therefore
1026 -- we label them with E_Access_Attribute_Type.
1028 if not Is_Overloaded (P) then
1029 Acc_Type := Build_Access_Object_Type (P_Type);
1030 Set_Etype (N, Acc_Type);
1032 else
1033 declare
1034 Index : Interp_Index;
1035 It : Interp;
1036 begin
1037 Set_Etype (N, Any_Type);
1038 Get_First_Interp (P, Index, It);
1039 while Present (It.Typ) loop
1040 Acc_Type := Build_Access_Object_Type (It.Typ);
1041 Add_One_Interp (N, Acc_Type, Acc_Type);
1042 Get_Next_Interp (Index, It);
1043 end loop;
1044 end;
1045 end if;
1047 -- Special cases when we can find a prefix that is an entity name
1049 declare
1050 PP : Node_Id;
1051 Ent : Entity_Id;
1053 begin
1054 PP := P;
1055 loop
1056 if Is_Entity_Name (PP) then
1057 Ent := Entity (PP);
1059 -- If we have an access to an object, and the attribute
1060 -- comes from source, then set the object as potentially
1061 -- source modified. We do this because the resulting access
1062 -- pointer can be used to modify the variable, and we might
1063 -- not detect this, leading to some junk warnings.
1065 -- We only do this for source references, since otherwise
1066 -- we can suppress warnings, e.g. from the unrestricted
1067 -- access generated for validity checks in -gnatVa mode.
1069 if Comes_From_Source (N) then
1070 Set_Never_Set_In_Source (Ent, False);
1071 end if;
1073 -- Mark entity as address taken in the case of
1074 -- 'Unrestricted_Access or subprograms, and kill current
1075 -- values.
1077 if Aname = Name_Unrestricted_Access
1078 or else Is_Subprogram (Ent)
1079 then
1080 Set_Address_Taken (Ent);
1081 end if;
1083 Kill_Current_Values (Ent);
1084 exit;
1086 elsif Nkind_In (PP, N_Selected_Component,
1087 N_Indexed_Component)
1088 then
1089 PP := Prefix (PP);
1091 else
1092 exit;
1093 end if;
1094 end loop;
1095 end;
1096 end Analyze_Access_Attribute;
1098 ----------------------------------
1099 -- Analyze_Attribute_Old_Result --
1100 ----------------------------------
1102 procedure Analyze_Attribute_Old_Result
1103 (Legal : out Boolean;
1104 Spec_Id : out Entity_Id)
1106 procedure Check_Placement_In_Check (Prag : Node_Id);
1107 -- Verify that the attribute appears within pragma Check that mimics
1108 -- a postcondition.
1110 procedure Check_Placement_In_Contract_Cases (Prag : Node_Id);
1111 -- Verify that the attribute appears within a consequence of aspect
1112 -- or pragma Contract_Cases denoted by Prag.
1114 procedure Check_Placement_In_Test_Case (Prag : Node_Id);
1115 -- Verify that the attribute appears within the "Ensures" argument of
1116 -- aspect or pragma Test_Case denoted by Prag.
1118 function Is_Within
1119 (Nod : Node_Id;
1120 Encl_Nod : Node_Id) return Boolean;
1121 -- Subsidiary to Check_Placemenet_In_XXX. Determine whether arbitrary
1122 -- node Nod is within enclosing node Encl_Nod.
1124 procedure Placement_Error;
1125 pragma No_Return (Placement_Error);
1126 -- Emit a general error when the attributes does not appear in a
1127 -- postcondition-like aspect or pragma, and then raises Bad_Attribute
1128 -- to avoid any further semantic processing.
1130 ------------------------------
1131 -- Check_Placement_In_Check --
1132 ------------------------------
1134 procedure Check_Placement_In_Check (Prag : Node_Id) is
1135 Args : constant List_Id := Pragma_Argument_Associations (Prag);
1136 Nam : constant Name_Id := Chars (Get_Pragma_Arg (First (Args)));
1138 begin
1139 -- The "Name" argument of pragma Check denotes a postcondition
1141 if Nam_In (Nam, Name_Post,
1142 Name_Post_Class,
1143 Name_Postcondition,
1144 Name_Refined_Post)
1145 then
1146 null;
1148 -- Otherwise the placement of the attribute is illegal
1150 else
1151 Placement_Error;
1152 end if;
1153 end Check_Placement_In_Check;
1155 ---------------------------------------
1156 -- Check_Placement_In_Contract_Cases --
1157 ---------------------------------------
1159 procedure Check_Placement_In_Contract_Cases (Prag : Node_Id) is
1160 Arg : Node_Id;
1161 Cases : Node_Id;
1162 CCase : Node_Id;
1164 begin
1165 -- Obtain the argument of the aspect or pragma
1167 if Nkind (Prag) = N_Aspect_Specification then
1168 Arg := Prag;
1169 else
1170 Arg := First (Pragma_Argument_Associations (Prag));
1171 end if;
1173 Cases := Expression (Arg);
1175 if Present (Component_Associations (Cases)) then
1176 CCase := First (Component_Associations (Cases));
1177 while Present (CCase) loop
1179 -- Detect whether the attribute appears within the
1180 -- consequence of the current contract case.
1182 if Nkind (CCase) = N_Component_Association
1183 and then Is_Within (N, Expression (CCase))
1184 then
1185 return;
1186 end if;
1188 Next (CCase);
1189 end loop;
1190 end if;
1192 -- Otherwise aspect or pragma Contract_Cases is either malformed
1193 -- or the attribute does not appear within a consequence.
1195 Error_Attr
1196 ("attribute % must appear in the consequence of a contract case",
1198 end Check_Placement_In_Contract_Cases;
1200 ----------------------------------
1201 -- Check_Placement_In_Test_Case --
1202 ----------------------------------
1204 procedure Check_Placement_In_Test_Case (Prag : Node_Id) is
1205 Arg : constant Node_Id :=
1206 Test_Case_Arg
1207 (Prag => Prag,
1208 Arg_Nam => Name_Ensures,
1209 From_Aspect => Nkind (Prag) = N_Aspect_Specification);
1211 begin
1212 -- Detect whether the attribute appears within the "Ensures"
1213 -- expression of aspect or pragma Test_Case.
1215 if Present (Arg) and then Is_Within (N, Arg) then
1216 null;
1218 else
1219 Error_Attr
1220 ("attribute % must appear in the ensures expression of a "
1221 & "test case", P);
1222 end if;
1223 end Check_Placement_In_Test_Case;
1225 ---------------
1226 -- Is_Within --
1227 ---------------
1229 function Is_Within
1230 (Nod : Node_Id;
1231 Encl_Nod : Node_Id) return Boolean
1233 Par : Node_Id;
1235 begin
1236 Par := Nod;
1237 while Present (Par) loop
1238 if Par = Encl_Nod then
1239 return True;
1241 -- Prevent the search from going too far
1243 elsif Is_Body_Or_Package_Declaration (Par) then
1244 exit;
1245 end if;
1247 Par := Parent (Par);
1248 end loop;
1250 return False;
1251 end Is_Within;
1253 ---------------------
1254 -- Placement_Error --
1255 ---------------------
1257 procedure Placement_Error is
1258 begin
1259 if Aname = Name_Old then
1260 Error_Attr ("attribute % can only appear in postcondition", P);
1262 -- Specialize the error message for attribute 'Result
1264 else
1265 Error_Attr
1266 ("attribute % can only appear in postcondition of function",
1268 end if;
1269 end Placement_Error;
1271 -- Local variables
1273 Prag : Node_Id;
1274 Prag_Nam : Name_Id;
1275 Subp_Decl : Node_Id;
1277 -- Start of processing for Analyze_Attribute_Old_Result
1279 begin
1280 -- Assume that the attribute is illegal
1282 Legal := False;
1283 Spec_Id := Empty;
1285 -- Traverse the parent chain to find the aspect or pragma where the
1286 -- attribute resides.
1288 Prag := N;
1289 while Present (Prag) loop
1290 if Nkind_In (Prag, N_Aspect_Specification, N_Pragma) then
1291 exit;
1293 -- Prevent the search from going too far
1295 elsif Is_Body_Or_Package_Declaration (Prag) then
1296 exit;
1297 end if;
1299 Prag := Parent (Prag);
1300 end loop;
1302 -- The attribute is allowed to appear only in postcondition-like
1303 -- aspects or pragmas.
1305 if Nkind_In (Prag, N_Aspect_Specification, N_Pragma) then
1306 if Nkind (Prag) = N_Aspect_Specification then
1307 Prag_Nam := Chars (Identifier (Prag));
1308 else
1309 Prag_Nam := Pragma_Name (Prag);
1310 end if;
1312 if Prag_Nam = Name_Check then
1313 Check_Placement_In_Check (Prag);
1315 elsif Prag_Nam = Name_Contract_Cases then
1316 Check_Placement_In_Contract_Cases (Prag);
1318 -- Attribute 'Result is allowed to appear in aspect or pragma
1319 -- [Refined_]Depends (SPARK RM 6.1.5(11)).
1321 elsif Nam_In (Prag_Nam, Name_Depends, Name_Refined_Depends)
1322 and then Aname = Name_Result
1323 then
1324 null;
1326 elsif Nam_In (Prag_Nam, Name_Post,
1327 Name_Post_Class,
1328 Name_Postcondition,
1329 Name_Refined_Post)
1330 then
1331 null;
1333 elsif Prag_Nam = Name_Test_Case then
1334 Check_Placement_In_Test_Case (Prag);
1336 else
1337 Placement_Error;
1338 return;
1339 end if;
1341 -- Otherwise the placement of the attribute is illegal
1343 else
1344 Placement_Error;
1345 return;
1346 end if;
1348 -- Find the related subprogram subject to the aspect or pragma
1350 if Nkind (Prag) = N_Aspect_Specification then
1351 Subp_Decl := Parent (Prag);
1352 else
1353 Subp_Decl := Find_Related_Declaration_Or_Body (Prag);
1354 end if;
1356 -- The aspect or pragma where the attribute resides should be
1357 -- associated with a subprogram declaration or a body. If this is not
1358 -- the case, then the aspect or pragma is illegal. Return as analysis
1359 -- cannot be carried out. Note that it is legal to have the aspect
1360 -- appear on a subprogram renaming, when the renamed entity is an
1361 -- attribute reference.
1363 -- Generating C code the internally built nested _postcondition
1364 -- subprograms are inlined; after expanded, inlined aspects are
1365 -- located in the internal block generated by the frontend.
1367 if Nkind (Subp_Decl) = N_Block_Statement
1368 and then Modify_Tree_For_C
1369 and then In_Inlined_Body
1370 then
1371 null;
1373 elsif not Nkind_In (Subp_Decl, N_Abstract_Subprogram_Declaration,
1374 N_Entry_Declaration,
1375 N_Expression_Function,
1376 N_Generic_Subprogram_Declaration,
1377 N_Subprogram_Body,
1378 N_Subprogram_Body_Stub,
1379 N_Subprogram_Declaration,
1380 N_Subprogram_Renaming_Declaration)
1381 then
1382 return;
1383 end if;
1385 -- If we get here, then the attribute is legal
1387 Legal := True;
1388 Spec_Id := Unique_Defining_Entity (Subp_Decl);
1390 -- When generating C code, nested _postcondition subprograms are
1391 -- inlined by the front end to avoid problems (when unnested) with
1392 -- referenced itypes. Handle that here, since as part of inlining the
1393 -- expander nests subprogram within a dummy procedure named _parent
1394 -- (see Build_Postconditions_Procedure and Build_Body_To_Inline).
1395 -- Hence, in this context, the spec_id of _postconditions is the
1396 -- enclosing scope.
1398 if Modify_Tree_For_C
1399 and then Chars (Spec_Id) = Name_uParent
1400 and then Chars (Scope (Spec_Id)) = Name_uPostconditions
1401 then
1402 -- This situation occurs only when preanalyzing the inlined body
1404 pragma Assert (not Full_Analysis);
1406 Spec_Id := Scope (Spec_Id);
1407 pragma Assert (Is_Inlined (Spec_Id));
1408 end if;
1409 end Analyze_Attribute_Old_Result;
1411 -----------------------------
1412 -- Analyze_Image_Attribute --
1413 -----------------------------
1415 procedure Analyze_Image_Attribute (Str_Typ : Entity_Id) is
1416 begin
1417 Check_SPARK_05_Restriction_On_Attribute;
1419 -- AI12-00124: The ARG has adopted the GNAT semantics of 'Img for
1420 -- scalar types, so that the prefix can be an object, a named value,
1421 -- or a type, and there is no need for an argument in this case.
1423 if Attr_Id = Attribute_Img
1424 or else (Ada_Version > Ada_2005 and then Is_Object_Image (P))
1425 then
1426 Check_E0;
1427 Set_Etype (N, Str_Typ);
1429 if Attr_Id = Attribute_Img and then not Is_Object_Image (P) then
1430 Error_Attr_P
1431 ("prefix of % attribute must be a scalar object name");
1432 end if;
1433 else
1434 Check_E1;
1435 Set_Etype (N, Str_Typ);
1437 -- Check that the prefix type is scalar - much in the same way as
1438 -- Check_Scalar_Type but with custom error messages to denote the
1439 -- variants of 'Image attributes.
1441 if Is_Entity_Name (P)
1442 and then Is_Type (Entity (P))
1443 and then Ekind (Entity (P)) = E_Incomplete_Type
1444 and then Present (Full_View (Entity (P)))
1445 then
1446 P_Type := Full_View (Entity (P));
1447 Set_Entity (P, P_Type);
1448 end if;
1450 if not Is_Entity_Name (P)
1451 or else not Is_Type (Entity (P))
1452 or else not Is_Scalar_Type (P_Type)
1453 then
1454 if Ada_Version > Ada_2005 then
1455 Error_Attr_P
1456 ("prefix of % attribute must be a scalar type or a scalar "
1457 & "object name");
1458 else
1459 Error_Attr_P ("prefix of % attribute must be a scalar type");
1460 end if;
1462 elsif Is_Protected_Self_Reference (P) then
1463 Error_Attr_P
1464 ("prefix of % attribute denotes current instance "
1465 & "(RM 9.4(21/2))");
1466 end if;
1468 Resolve (E1, P_Base_Type);
1469 Validate_Non_Static_Attribute_Function_Call;
1470 end if;
1472 Check_Enum_Image;
1474 -- Check restriction No_Fixed_IO. Note the check of Comes_From_Source
1475 -- to avoid giving a duplicate message for when Image attributes
1476 -- applied to object references get expanded into type-based Image
1477 -- attributes.
1479 if Restriction_Check_Required (No_Fixed_IO)
1480 and then Comes_From_Source (N)
1481 and then Is_Fixed_Point_Type (P_Type)
1482 then
1483 Check_Restriction (No_Fixed_IO, P);
1484 end if;
1485 end Analyze_Image_Attribute;
1487 ---------------------------------
1488 -- Bad_Attribute_For_Predicate --
1489 ---------------------------------
1491 procedure Bad_Attribute_For_Predicate is
1492 begin
1493 if Is_Scalar_Type (P_Type)
1494 and then Comes_From_Source (N)
1495 then
1496 Error_Msg_Name_1 := Aname;
1497 Bad_Predicated_Subtype_Use
1498 ("type& has predicates, attribute % not allowed", N, P_Type);
1499 end if;
1500 end Bad_Attribute_For_Predicate;
1502 --------------------------------
1503 -- Check_Array_Or_Scalar_Type --
1504 --------------------------------
1506 procedure Check_Array_Or_Scalar_Type is
1507 function In_Aspect_Specification return Boolean;
1508 -- A current instance of a type in an aspect specification is an
1509 -- object and not a type, and therefore cannot be of a scalar type
1510 -- in the prefix of one of the array attributes if the attribute
1511 -- reference is part of an aspect expression.
1513 -----------------------------
1514 -- In_Aspect_Specification --
1515 -----------------------------
1517 function In_Aspect_Specification return Boolean is
1518 P : Node_Id;
1520 begin
1521 P := Parent (N);
1522 while Present (P) loop
1523 if Nkind (P) = N_Aspect_Specification then
1524 return P_Type = Entity (P);
1526 elsif Nkind (P) in N_Declaration then
1527 return False;
1528 end if;
1530 P := Parent (P);
1531 end loop;
1533 return False;
1534 end In_Aspect_Specification;
1536 -- Local variables
1538 Dims : Int;
1539 Index : Entity_Id;
1541 -- Start of processing for Check_Array_Or_Scalar_Type
1543 begin
1544 -- Case of string literal or string literal subtype. These cases
1545 -- cannot arise from legal Ada code, but the expander is allowed
1546 -- to generate them. They require special handling because string
1547 -- literal subtypes do not have standard bounds (the whole idea
1548 -- of these subtypes is to avoid having to generate the bounds)
1550 if Ekind (P_Type) = E_String_Literal_Subtype then
1551 Set_Etype (N, Etype (First_Index (P_Base_Type)));
1552 return;
1554 -- Scalar types
1556 elsif Is_Scalar_Type (P_Type) then
1557 Check_Type;
1559 if Present (E1) then
1560 Error_Attr ("invalid argument in % attribute", E1);
1562 elsif In_Aspect_Specification then
1563 Error_Attr
1564 ("prefix of % attribute cannot be the current instance of a "
1565 & "scalar type", P);
1567 else
1568 Set_Etype (N, P_Base_Type);
1569 return;
1570 end if;
1572 -- The following is a special test to allow 'First to apply to
1573 -- private scalar types if the attribute comes from generated
1574 -- code. This occurs in the case of Normalize_Scalars code.
1576 elsif Is_Private_Type (P_Type)
1577 and then Present (Full_View (P_Type))
1578 and then Is_Scalar_Type (Full_View (P_Type))
1579 and then not Comes_From_Source (N)
1580 then
1581 Set_Etype (N, Implementation_Base_Type (P_Type));
1583 -- Array types other than string literal subtypes handled above
1585 else
1586 Check_Array_Type;
1588 -- We know prefix is an array type, or the name of an array
1589 -- object, and that the expression, if present, is static
1590 -- and within the range of the dimensions of the type.
1592 pragma Assert (Is_Array_Type (P_Type));
1593 Index := First_Index (P_Base_Type);
1595 if No (E1) then
1597 -- First dimension assumed
1599 Set_Etype (N, Base_Type (Etype (Index)));
1601 else
1602 Dims := UI_To_Int (Intval (E1));
1604 for J in 1 .. Dims - 1 loop
1605 Next_Index (Index);
1606 end loop;
1608 Set_Etype (N, Base_Type (Etype (Index)));
1609 Set_Etype (E1, Standard_Integer);
1610 end if;
1611 end if;
1612 end Check_Array_Or_Scalar_Type;
1614 ----------------------
1615 -- Check_Array_Type --
1616 ----------------------
1618 procedure Check_Array_Type is
1619 D : Int;
1620 -- Dimension number for array attributes
1622 begin
1623 -- If the type is a string literal type, then this must be generated
1624 -- internally, and no further check is required on its legality.
1626 if Ekind (P_Type) = E_String_Literal_Subtype then
1627 return;
1629 -- If the type is a composite, it is an illegal aggregate, no point
1630 -- in going on.
1632 elsif P_Type = Any_Composite then
1633 raise Bad_Attribute;
1634 end if;
1636 -- Normal case of array type or subtype
1638 Check_Either_E0_Or_E1;
1639 Check_Dereference;
1641 if Is_Array_Type (P_Type) then
1642 if not Is_Constrained (P_Type)
1643 and then Is_Entity_Name (P)
1644 and then Is_Type (Entity (P))
1645 then
1646 -- Note: we do not call Error_Attr here, since we prefer to
1647 -- continue, using the relevant index type of the array,
1648 -- even though it is unconstrained. This gives better error
1649 -- recovery behavior.
1651 Error_Msg_Name_1 := Aname;
1652 Error_Msg_F
1653 ("prefix for % attribute must be constrained array", P);
1654 end if;
1656 -- The attribute reference freezes the type, and thus the
1657 -- component type, even if the attribute may not depend on the
1658 -- component. Diagnose arrays with incomplete components now.
1659 -- If the prefix is an access to array, this does not freeze
1660 -- the designated type.
1662 if Nkind (P) /= N_Explicit_Dereference then
1663 Check_Fully_Declared (Component_Type (P_Type), P);
1664 end if;
1666 D := Number_Dimensions (P_Type);
1668 else
1669 if Is_Private_Type (P_Type) then
1670 Error_Attr_P ("prefix for % attribute may not be private type");
1672 elsif Is_Access_Type (P_Type)
1673 and then Is_Array_Type (Designated_Type (P_Type))
1674 and then Is_Entity_Name (P)
1675 and then Is_Type (Entity (P))
1676 then
1677 Error_Attr_P ("prefix of % attribute cannot be access type");
1679 elsif Attr_Id = Attribute_First
1680 or else
1681 Attr_Id = Attribute_Last
1682 then
1683 Error_Attr ("invalid prefix for % attribute", P);
1685 else
1686 Error_Attr_P ("prefix for % attribute must be array");
1687 end if;
1688 end if;
1690 if Present (E1) then
1691 Resolve (E1, Any_Integer);
1692 Set_Etype (E1, Standard_Integer);
1694 if not Is_OK_Static_Expression (E1)
1695 or else Raises_Constraint_Error (E1)
1696 then
1697 Flag_Non_Static_Expr
1698 ("expression for dimension must be static!", E1);
1699 Error_Attr;
1701 elsif UI_To_Int (Expr_Value (E1)) > D
1702 or else UI_To_Int (Expr_Value (E1)) < 1
1703 then
1704 Error_Attr ("invalid dimension number for array type", E1);
1705 end if;
1706 end if;
1708 if (Style_Check and Style_Check_Array_Attribute_Index)
1709 and then Comes_From_Source (N)
1710 then
1711 Style.Check_Array_Attribute_Index (N, E1, D);
1712 end if;
1713 end Check_Array_Type;
1715 -------------------------
1716 -- Check_Asm_Attribute --
1717 -------------------------
1719 procedure Check_Asm_Attribute is
1720 begin
1721 Check_Type;
1722 Check_E2;
1724 -- Check first argument is static string expression
1726 Analyze_And_Resolve (E1, Standard_String);
1728 if Etype (E1) = Any_Type then
1729 return;
1731 elsif not Is_OK_Static_Expression (E1) then
1732 Flag_Non_Static_Expr
1733 ("constraint argument must be static string expression!", E1);
1734 Error_Attr;
1735 end if;
1737 -- Check second argument is right type
1739 Analyze_And_Resolve (E2, Entity (P));
1741 -- Note: that is all we need to do, we don't need to check
1742 -- that it appears in a correct context. The Ada type system
1743 -- will do that for us.
1745 end Check_Asm_Attribute;
1747 ---------------------
1748 -- Check_Component --
1749 ---------------------
1751 procedure Check_Component is
1752 begin
1753 Check_E0;
1755 if Nkind (P) /= N_Selected_Component
1756 or else
1757 (Ekind (Entity (Selector_Name (P))) /= E_Component
1758 and then
1759 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1760 then
1761 Error_Attr_P ("prefix for % attribute must be selected component");
1762 end if;
1763 end Check_Component;
1765 ------------------------------------
1766 -- Check_Decimal_Fixed_Point_Type --
1767 ------------------------------------
1769 procedure Check_Decimal_Fixed_Point_Type is
1770 begin
1771 Check_Type;
1773 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1774 Error_Attr_P ("prefix of % attribute must be decimal type");
1775 end if;
1776 end Check_Decimal_Fixed_Point_Type;
1778 -----------------------
1779 -- Check_Dereference --
1780 -----------------------
1782 procedure Check_Dereference is
1783 begin
1785 -- Case of a subtype mark
1787 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
1788 return;
1789 end if;
1791 -- Case of an expression
1793 Resolve (P);
1795 if Is_Access_Type (P_Type) then
1797 -- If there is an implicit dereference, then we must freeze the
1798 -- designated type of the access type, since the type of the
1799 -- referenced array is this type (see AI95-00106).
1801 -- As done elsewhere, freezing must not happen when pre-analyzing
1802 -- a pre- or postcondition or a default value for an object or for
1803 -- a formal parameter.
1805 if not In_Spec_Expression then
1806 Freeze_Before (N, Designated_Type (P_Type));
1807 end if;
1809 Rewrite (P,
1810 Make_Explicit_Dereference (Sloc (P),
1811 Prefix => Relocate_Node (P)));
1813 Analyze_And_Resolve (P);
1814 P_Type := Etype (P);
1816 if P_Type = Any_Type then
1817 raise Bad_Attribute;
1818 end if;
1820 P_Base_Type := Base_Type (P_Type);
1821 end if;
1822 end Check_Dereference;
1824 -------------------------
1825 -- Check_Discrete_Type --
1826 -------------------------
1828 procedure Check_Discrete_Type is
1829 begin
1830 Check_Type;
1832 if not Is_Discrete_Type (P_Type) then
1833 Error_Attr_P ("prefix of % attribute must be discrete type");
1834 end if;
1835 end Check_Discrete_Type;
1837 --------------
1838 -- Check_E0 --
1839 --------------
1841 procedure Check_E0 is
1842 begin
1843 if Present (E1) then
1844 Unexpected_Argument (E1);
1845 end if;
1846 end Check_E0;
1848 --------------
1849 -- Check_E1 --
1850 --------------
1852 procedure Check_E1 is
1853 begin
1854 Check_Either_E0_Or_E1;
1856 if No (E1) then
1858 -- Special-case attributes that are functions and that appear as
1859 -- the prefix of another attribute. Error is posted on parent.
1861 if Nkind (Parent (N)) = N_Attribute_Reference
1862 and then Nam_In (Attribute_Name (Parent (N)), Name_Address,
1863 Name_Code_Address,
1864 Name_Access)
1865 then
1866 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1867 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1868 Set_Etype (Parent (N), Any_Type);
1869 Set_Entity (Parent (N), Any_Type);
1870 raise Bad_Attribute;
1872 else
1873 Error_Attr ("missing argument for % attribute", N);
1874 end if;
1875 end if;
1876 end Check_E1;
1878 --------------
1879 -- Check_E2 --
1880 --------------
1882 procedure Check_E2 is
1883 begin
1884 if No (E1) then
1885 Error_Attr ("missing arguments for % attribute (2 required)", N);
1886 elsif No (E2) then
1887 Error_Attr ("missing argument for % attribute (2 required)", N);
1888 end if;
1889 end Check_E2;
1891 ---------------------------
1892 -- Check_Either_E0_Or_E1 --
1893 ---------------------------
1895 procedure Check_Either_E0_Or_E1 is
1896 begin
1897 if Present (E2) then
1898 Unexpected_Argument (E2);
1899 end if;
1900 end Check_Either_E0_Or_E1;
1902 ----------------------
1903 -- Check_Enum_Image --
1904 ----------------------
1906 procedure Check_Enum_Image is
1907 Lit : Entity_Id;
1909 begin
1910 -- When an enumeration type appears in an attribute reference, all
1911 -- literals of the type are marked as referenced. This must only be
1912 -- done if the attribute reference appears in the current source.
1913 -- Otherwise the information on references may differ between a
1914 -- normal compilation and one that performs inlining.
1916 if Is_Enumeration_Type (P_Base_Type)
1917 and then In_Extended_Main_Code_Unit (N)
1918 then
1919 Lit := First_Literal (P_Base_Type);
1920 while Present (Lit) loop
1921 Set_Referenced (Lit);
1922 Next_Literal (Lit);
1923 end loop;
1924 end if;
1925 end Check_Enum_Image;
1927 ----------------------------
1928 -- Check_First_Last_Valid --
1929 ----------------------------
1931 procedure Check_First_Last_Valid is
1932 begin
1933 Check_Discrete_Type;
1935 -- Freeze the subtype now, so that the following test for predicates
1936 -- works (we set the predicates stuff up at freeze time)
1938 Insert_Actions (N, Freeze_Entity (P_Type, P));
1940 -- Now test for dynamic predicate
1942 if Has_Predicates (P_Type)
1943 and then not (Has_Static_Predicate (P_Type))
1944 then
1945 Error_Attr_P
1946 ("prefix of % attribute may not have dynamic predicate");
1947 end if;
1949 -- Check non-static subtype
1951 if not Is_OK_Static_Subtype (P_Type) then
1952 Error_Attr_P ("prefix of % attribute must be a static subtype");
1953 end if;
1955 -- Test case for no values
1957 if Expr_Value (Type_Low_Bound (P_Type)) >
1958 Expr_Value (Type_High_Bound (P_Type))
1959 or else (Has_Predicates (P_Type)
1960 and then
1961 Is_Empty_List (Static_Discrete_Predicate (P_Type)))
1962 then
1963 Error_Attr_P
1964 ("prefix of % attribute must be subtype with at least one "
1965 & "value");
1966 end if;
1967 end Check_First_Last_Valid;
1969 ----------------------------
1970 -- Check_Fixed_Point_Type --
1971 ----------------------------
1973 procedure Check_Fixed_Point_Type is
1974 begin
1975 Check_Type;
1977 if not Is_Fixed_Point_Type (P_Type) then
1978 Error_Attr_P ("prefix of % attribute must be fixed point type");
1979 end if;
1980 end Check_Fixed_Point_Type;
1982 ------------------------------
1983 -- Check_Fixed_Point_Type_0 --
1984 ------------------------------
1986 procedure Check_Fixed_Point_Type_0 is
1987 begin
1988 Check_Fixed_Point_Type;
1989 Check_E0;
1990 end Check_Fixed_Point_Type_0;
1992 -------------------------------
1993 -- Check_Floating_Point_Type --
1994 -------------------------------
1996 procedure Check_Floating_Point_Type is
1997 begin
1998 Check_Type;
2000 if not Is_Floating_Point_Type (P_Type) then
2001 Error_Attr_P ("prefix of % attribute must be float type");
2002 end if;
2003 end Check_Floating_Point_Type;
2005 ---------------------------------
2006 -- Check_Floating_Point_Type_0 --
2007 ---------------------------------
2009 procedure Check_Floating_Point_Type_0 is
2010 begin
2011 Check_Floating_Point_Type;
2012 Check_E0;
2013 end Check_Floating_Point_Type_0;
2015 ---------------------------------
2016 -- Check_Floating_Point_Type_1 --
2017 ---------------------------------
2019 procedure Check_Floating_Point_Type_1 is
2020 begin
2021 Check_Floating_Point_Type;
2022 Check_E1;
2023 end Check_Floating_Point_Type_1;
2025 ---------------------------------
2026 -- Check_Floating_Point_Type_2 --
2027 ---------------------------------
2029 procedure Check_Floating_Point_Type_2 is
2030 begin
2031 Check_Floating_Point_Type;
2032 Check_E2;
2033 end Check_Floating_Point_Type_2;
2035 ------------------------
2036 -- Check_Integer_Type --
2037 ------------------------
2039 procedure Check_Integer_Type is
2040 begin
2041 Check_Type;
2043 if not Is_Integer_Type (P_Type) then
2044 Error_Attr_P ("prefix of % attribute must be integer type");
2045 end if;
2046 end Check_Integer_Type;
2048 --------------------------------
2049 -- Check_Modular_Integer_Type --
2050 --------------------------------
2052 procedure Check_Modular_Integer_Type is
2053 begin
2054 Check_Type;
2056 if not Is_Modular_Integer_Type (P_Type) then
2057 Error_Attr_P
2058 ("prefix of % attribute must be modular integer type");
2059 end if;
2060 end Check_Modular_Integer_Type;
2062 ------------------------
2063 -- Check_Not_CPP_Type --
2064 ------------------------
2066 procedure Check_Not_CPP_Type is
2067 begin
2068 if Is_Tagged_Type (Etype (P))
2069 and then Convention (Etype (P)) = Convention_CPP
2070 and then Is_CPP_Class (Root_Type (Etype (P)))
2071 then
2072 Error_Attr_P
2073 ("invalid use of % attribute with 'C'P'P tagged type");
2074 end if;
2075 end Check_Not_CPP_Type;
2077 -------------------------------
2078 -- Check_Not_Incomplete_Type --
2079 -------------------------------
2081 procedure Check_Not_Incomplete_Type is
2082 E : Entity_Id;
2083 Typ : Entity_Id;
2085 begin
2086 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
2087 -- dereference we have to check wrong uses of incomplete types
2088 -- (other wrong uses are checked at their freezing point).
2090 -- In Ada 2012, incomplete types can appear in subprogram
2091 -- profiles, but formals with incomplete types cannot be the
2092 -- prefix of attributes.
2094 -- Example 1: Limited-with
2096 -- limited with Pkg;
2097 -- package P is
2098 -- type Acc is access Pkg.T;
2099 -- X : Acc;
2100 -- S : Integer := X.all'Size; -- ERROR
2101 -- end P;
2103 -- Example 2: Tagged incomplete
2105 -- type T is tagged;
2106 -- type Acc is access all T;
2107 -- X : Acc;
2108 -- S : constant Integer := X.all'Size; -- ERROR
2109 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
2111 if Ada_Version >= Ada_2005
2112 and then Nkind (P) = N_Explicit_Dereference
2113 then
2114 E := P;
2115 while Nkind (E) = N_Explicit_Dereference loop
2116 E := Prefix (E);
2117 end loop;
2119 Typ := Etype (E);
2121 if From_Limited_With (Typ) then
2122 Error_Attr_P
2123 ("prefix of % attribute cannot be an incomplete type");
2125 -- If the prefix is an access type check the designated type
2127 elsif Is_Access_Type (Typ)
2128 and then Nkind (P) = N_Explicit_Dereference
2129 then
2130 Typ := Directly_Designated_Type (Typ);
2131 end if;
2133 if Is_Class_Wide_Type (Typ) then
2134 Typ := Root_Type (Typ);
2135 end if;
2137 -- A legal use of a shadow entity occurs only when the unit where
2138 -- the non-limited view resides is imported via a regular with
2139 -- clause in the current body. Such references to shadow entities
2140 -- may occur in subprogram formals.
2142 if Is_Incomplete_Type (Typ)
2143 and then From_Limited_With (Typ)
2144 and then Present (Non_Limited_View (Typ))
2145 and then Is_Legal_Shadow_Entity_In_Body (Typ)
2146 then
2147 Typ := Non_Limited_View (Typ);
2148 end if;
2150 -- If still incomplete, it can be a local incomplete type, or a
2151 -- limited view whose scope is also a limited view.
2153 if Ekind (Typ) = E_Incomplete_Type then
2154 if not From_Limited_With (Typ)
2155 and then No (Full_View (Typ))
2156 then
2157 Error_Attr_P
2158 ("prefix of % attribute cannot be an incomplete type");
2160 -- The limited view may be available indirectly through
2161 -- an intermediate unit. If the non-limited view is available
2162 -- the attribute reference is legal.
2164 elsif From_Limited_With (Typ)
2165 and then
2166 (No (Non_Limited_View (Typ))
2167 or else Is_Incomplete_Type (Non_Limited_View (Typ)))
2168 then
2169 Error_Attr_P
2170 ("prefix of % attribute cannot be an incomplete type");
2171 end if;
2172 end if;
2174 -- Ada 2012 : formals in bodies may be incomplete, but no attribute
2175 -- legally applies.
2177 elsif Is_Entity_Name (P)
2178 and then Is_Formal (Entity (P))
2179 and then Is_Incomplete_Type (Etype (Etype (P)))
2180 then
2181 Error_Attr_P
2182 ("prefix of % attribute cannot be an incomplete type");
2183 end if;
2185 if not Is_Entity_Name (P)
2186 or else not Is_Type (Entity (P))
2187 or else In_Spec_Expression
2188 then
2189 return;
2190 else
2191 Check_Fully_Declared (P_Type, P);
2192 end if;
2193 end Check_Not_Incomplete_Type;
2195 ----------------------------
2196 -- Check_Object_Reference --
2197 ----------------------------
2199 procedure Check_Object_Reference (P : Node_Id) is
2200 Rtyp : Entity_Id;
2202 begin
2203 -- If we need an object, and we have a prefix that is the name of
2204 -- a function entity, convert it into a function call.
2206 if Is_Entity_Name (P)
2207 and then Ekind (Entity (P)) = E_Function
2208 then
2209 Rtyp := Etype (Entity (P));
2211 Rewrite (P,
2212 Make_Function_Call (Sloc (P),
2213 Name => Relocate_Node (P)));
2215 Analyze_And_Resolve (P, Rtyp);
2217 -- Otherwise we must have an object reference
2219 elsif not Is_Object_Reference (P) then
2220 Error_Attr_P ("prefix of % attribute must be object");
2221 end if;
2222 end Check_Object_Reference;
2224 ----------------------------
2225 -- Check_PolyORB_Attribute --
2226 ----------------------------
2228 procedure Check_PolyORB_Attribute is
2229 begin
2230 Validate_Non_Static_Attribute_Function_Call;
2232 Check_Type;
2233 Check_Not_CPP_Type;
2235 if Get_PCS_Name /= Name_PolyORB_DSA then
2236 Error_Attr
2237 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
2238 end if;
2239 end Check_PolyORB_Attribute;
2241 ------------------------
2242 -- Check_Program_Unit --
2243 ------------------------
2245 procedure Check_Program_Unit is
2246 begin
2247 if Is_Entity_Name (P) then
2248 declare
2249 K : constant Entity_Kind := Ekind (Entity (P));
2250 T : constant Entity_Id := Etype (Entity (P));
2252 begin
2253 if K in Subprogram_Kind
2254 or else K in Task_Kind
2255 or else K in Protected_Kind
2256 or else K = E_Package
2257 or else K in Generic_Unit_Kind
2258 or else (K = E_Variable
2259 and then
2260 (Is_Task_Type (T)
2261 or else
2262 Is_Protected_Type (T)))
2263 then
2264 return;
2265 end if;
2266 end;
2267 end if;
2269 Error_Attr_P ("prefix of % attribute must be program unit");
2270 end Check_Program_Unit;
2272 ---------------------
2273 -- Check_Real_Type --
2274 ---------------------
2276 procedure Check_Real_Type is
2277 begin
2278 Check_Type;
2280 if not Is_Real_Type (P_Type) then
2281 Error_Attr_P ("prefix of % attribute must be real type");
2282 end if;
2283 end Check_Real_Type;
2285 -----------------------
2286 -- Check_Scalar_Type --
2287 -----------------------
2289 procedure Check_Scalar_Type is
2290 begin
2291 Check_Type;
2293 if not Is_Scalar_Type (P_Type) then
2294 Error_Attr_P ("prefix of % attribute must be scalar type");
2295 end if;
2296 end Check_Scalar_Type;
2298 ------------------------------------------
2299 -- Check_SPARK_05_Restriction_On_Attribute --
2300 ------------------------------------------
2302 procedure Check_SPARK_05_Restriction_On_Attribute is
2303 begin
2304 Error_Msg_Name_1 := Aname;
2305 Check_SPARK_05_Restriction ("attribute % is not allowed", P);
2306 end Check_SPARK_05_Restriction_On_Attribute;
2308 ---------------------------
2309 -- Check_Standard_Prefix --
2310 ---------------------------
2312 procedure Check_Standard_Prefix is
2313 begin
2314 Check_E0;
2316 if Nkind (P) /= N_Identifier or else Chars (P) /= Name_Standard then
2317 Error_Attr ("only allowed prefix for % attribute is Standard", P);
2318 end if;
2319 end Check_Standard_Prefix;
2321 ----------------------------
2322 -- Check_Stream_Attribute --
2323 ----------------------------
2325 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
2326 Etyp : Entity_Id;
2327 Btyp : Entity_Id;
2329 In_Shared_Var_Procs : Boolean;
2330 -- True when compiling System.Shared_Storage.Shared_Var_Procs body.
2331 -- For this runtime package (always compiled in GNAT mode), we allow
2332 -- stream attributes references for limited types for the case where
2333 -- shared passive objects are implemented using stream attributes,
2334 -- which is the default in GNAT's persistent storage implementation.
2336 begin
2337 Validate_Non_Static_Attribute_Function_Call;
2339 -- With the exception of 'Input, Stream attributes are procedures,
2340 -- and can only appear at the position of procedure calls. We check
2341 -- for this here, before they are rewritten, to give a more precise
2342 -- diagnostic.
2344 if Nam = TSS_Stream_Input then
2345 null;
2347 elsif Is_List_Member (N)
2348 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
2349 N_Aggregate)
2350 then
2351 null;
2353 else
2354 Error_Attr
2355 ("invalid context for attribute%, which is a procedure", N);
2356 end if;
2358 Check_Type;
2359 Btyp := Implementation_Base_Type (P_Type);
2361 -- Stream attributes not allowed on limited types unless the
2362 -- attribute reference was generated by the expander (in which
2363 -- case the underlying type will be used, as described in Sinfo),
2364 -- or the attribute was specified explicitly for the type itself
2365 -- or one of its ancestors (taking visibility rules into account if
2366 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
2367 -- (with no visibility restriction).
2369 declare
2370 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
2371 begin
2372 if Present (Gen_Body) then
2373 In_Shared_Var_Procs :=
2374 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
2375 else
2376 In_Shared_Var_Procs := False;
2377 end if;
2378 end;
2380 if (Comes_From_Source (N)
2381 and then not (In_Shared_Var_Procs or In_Instance))
2382 and then not Stream_Attribute_Available (P_Type, Nam)
2383 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
2384 then
2385 Error_Msg_Name_1 := Aname;
2387 if Is_Limited_Type (P_Type) then
2388 Error_Msg_NE
2389 ("limited type& has no% attribute", P, P_Type);
2390 Explain_Limited_Type (P_Type, P);
2391 else
2392 Error_Msg_NE
2393 ("attribute% for type& is not available", P, P_Type);
2394 end if;
2395 end if;
2397 -- Check for no stream operations allowed from No_Tagged_Streams
2399 if Is_Tagged_Type (P_Type)
2400 and then Present (No_Tagged_Streams_Pragma (P_Type))
2401 then
2402 Error_Msg_Sloc := Sloc (No_Tagged_Streams_Pragma (P_Type));
2403 Error_Msg_NE
2404 ("no stream operations for & (No_Tagged_Streams #)", N, P_Type);
2405 return;
2406 end if;
2408 -- Check restriction violations
2410 -- First check the No_Streams restriction, which prohibits the use
2411 -- of explicit stream attributes in the source program. We do not
2412 -- prevent the occurrence of stream attributes in generated code,
2413 -- for instance those generated implicitly for dispatching purposes.
2415 if Comes_From_Source (N) then
2416 Check_Restriction (No_Streams, P);
2417 end if;
2419 -- AI05-0057: if restriction No_Default_Stream_Attributes is active,
2420 -- it is illegal to use a predefined elementary type stream attribute
2421 -- either by itself, or more importantly as part of the attribute
2422 -- subprogram for a composite type. However, if the broader
2423 -- restriction No_Streams is active, stream operations are not
2424 -- generated, and there is no error.
2426 if Restriction_Active (No_Default_Stream_Attributes)
2427 and then not Restriction_Active (No_Streams)
2428 then
2429 declare
2430 T : Entity_Id;
2432 begin
2433 if Nam = TSS_Stream_Input
2434 or else
2435 Nam = TSS_Stream_Read
2436 then
2437 T :=
2438 Type_Without_Stream_Operation (P_Type, TSS_Stream_Read);
2439 else
2440 T :=
2441 Type_Without_Stream_Operation (P_Type, TSS_Stream_Write);
2442 end if;
2444 if Present (T) then
2445 Check_Restriction (No_Default_Stream_Attributes, N);
2447 Error_Msg_NE
2448 ("missing user-defined Stream Read or Write for type&",
2449 N, T);
2450 if not Is_Elementary_Type (P_Type) then
2451 Error_Msg_NE
2452 ("\which is a component of type&", N, P_Type);
2453 end if;
2454 end if;
2455 end;
2456 end if;
2458 -- Check special case of Exception_Id and Exception_Occurrence which
2459 -- are not allowed for restriction No_Exception_Registration.
2461 if Restriction_Check_Required (No_Exception_Registration)
2462 and then (Is_RTE (P_Type, RE_Exception_Id)
2463 or else
2464 Is_RTE (P_Type, RE_Exception_Occurrence))
2465 then
2466 Check_Restriction (No_Exception_Registration, P);
2467 end if;
2469 -- Here we must check that the first argument is an access type
2470 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
2472 Analyze_And_Resolve (E1);
2473 Etyp := Etype (E1);
2475 -- Note: the double call to Root_Type here is needed because the
2476 -- root type of a class-wide type is the corresponding type (e.g.
2477 -- X for X'Class, and we really want to go to the root.)
2479 if not Is_Access_Type (Etyp)
2480 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
2481 RTE (RE_Root_Stream_Type)
2482 then
2483 Error_Attr
2484 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
2485 end if;
2487 -- Check that the second argument is of the right type if there is
2488 -- one (the Input attribute has only one argument so this is skipped)
2490 if Present (E2) then
2491 Analyze (E2);
2493 if Nam = TSS_Stream_Read
2494 and then not Is_OK_Variable_For_Out_Formal (E2)
2495 then
2496 Error_Attr
2497 ("second argument of % attribute must be a variable", E2);
2498 end if;
2500 Resolve (E2, P_Type);
2501 end if;
2503 Check_Not_CPP_Type;
2504 end Check_Stream_Attribute;
2506 -------------------------
2507 -- Check_System_Prefix --
2508 -------------------------
2510 procedure Check_System_Prefix is
2511 begin
2512 if Nkind (P) /= N_Identifier or else Chars (P) /= Name_System then
2513 Error_Attr ("only allowed prefix for % attribute is System", P);
2514 end if;
2515 end Check_System_Prefix;
2517 -----------------------
2518 -- Check_Task_Prefix --
2519 -----------------------
2521 procedure Check_Task_Prefix is
2522 begin
2523 Analyze (P);
2525 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
2526 -- task interface class-wide types.
2528 if Is_Task_Type (Etype (P))
2529 or else (Is_Access_Type (Etype (P))
2530 and then Is_Task_Type (Designated_Type (Etype (P))))
2531 or else (Ada_Version >= Ada_2005
2532 and then Ekind (Etype (P)) = E_Class_Wide_Type
2533 and then Is_Interface (Etype (P))
2534 and then Is_Task_Interface (Etype (P)))
2535 then
2536 Resolve (P);
2538 else
2539 if Ada_Version >= Ada_2005 then
2540 Error_Attr_P
2541 ("prefix of % attribute must be a task or a task " &
2542 "interface class-wide object");
2544 else
2545 Error_Attr_P ("prefix of % attribute must be a task");
2546 end if;
2547 end if;
2548 end Check_Task_Prefix;
2550 ----------------
2551 -- Check_Type --
2552 ----------------
2554 -- The possibilities are an entity name denoting a type, or an
2555 -- attribute reference that denotes a type (Base or Class). If
2556 -- the type is incomplete, replace it with its full view.
2558 procedure Check_Type is
2559 begin
2560 if not Is_Entity_Name (P)
2561 or else not Is_Type (Entity (P))
2562 then
2563 Error_Attr_P ("prefix of % attribute must be a type");
2565 elsif Is_Protected_Self_Reference (P) then
2566 Error_Attr_P
2567 ("prefix of % attribute denotes current instance "
2568 & "(RM 9.4(21/2))");
2570 elsif Ekind (Entity (P)) = E_Incomplete_Type
2571 and then Present (Full_View (Entity (P)))
2572 then
2573 P_Type := Full_View (Entity (P));
2574 Set_Entity (P, P_Type);
2575 end if;
2576 end Check_Type;
2578 ---------------------
2579 -- Check_Unit_Name --
2580 ---------------------
2582 procedure Check_Unit_Name (Nod : Node_Id) is
2583 begin
2584 if Nkind (Nod) = N_Identifier then
2585 return;
2587 elsif Nkind_In (Nod, N_Selected_Component, N_Expanded_Name) then
2588 Check_Unit_Name (Prefix (Nod));
2590 if Nkind (Selector_Name (Nod)) = N_Identifier then
2591 return;
2592 end if;
2593 end if;
2595 Error_Attr ("argument for % attribute must be unit name", P);
2596 end Check_Unit_Name;
2598 ----------------
2599 -- Error_Attr --
2600 ----------------
2602 procedure Error_Attr is
2603 begin
2604 Set_Etype (N, Any_Type);
2605 Set_Entity (N, Any_Type);
2606 raise Bad_Attribute;
2607 end Error_Attr;
2609 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
2610 begin
2611 Error_Msg_Name_1 := Aname;
2612 Error_Msg_N (Msg, Error_Node);
2613 Error_Attr;
2614 end Error_Attr;
2616 ------------------
2617 -- Error_Attr_P --
2618 ------------------
2620 procedure Error_Attr_P (Msg : String) is
2621 begin
2622 Error_Msg_Name_1 := Aname;
2623 Error_Msg_F (Msg, P);
2624 Error_Attr;
2625 end Error_Attr_P;
2627 ----------------------------
2628 -- Legal_Formal_Attribute --
2629 ----------------------------
2631 procedure Legal_Formal_Attribute is
2632 begin
2633 Check_E0;
2635 if not Is_Entity_Name (P)
2636 or else not Is_Type (Entity (P))
2637 then
2638 Error_Attr_P ("prefix of % attribute must be generic type");
2640 elsif Is_Generic_Actual_Type (Entity (P))
2641 or else In_Instance
2642 or else In_Inlined_Body
2643 then
2644 null;
2646 elsif Is_Generic_Type (Entity (P)) then
2647 if Is_Definite_Subtype (Entity (P)) then
2648 Error_Attr_P
2649 ("prefix of % attribute must be indefinite generic type");
2650 end if;
2652 else
2653 Error_Attr_P
2654 ("prefix of % attribute must be indefinite generic type");
2655 end if;
2657 Set_Etype (N, Standard_Boolean);
2658 end Legal_Formal_Attribute;
2660 ---------------------------------------------------------------
2661 -- Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements --
2662 ---------------------------------------------------------------
2664 procedure Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements is
2665 begin
2666 Check_E0;
2667 Check_Type;
2668 Check_Not_Incomplete_Type;
2669 Set_Etype (N, Universal_Integer);
2670 end Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
2672 -------------
2673 -- Min_Max --
2674 -------------
2676 procedure Min_Max is
2677 begin
2678 Check_E2;
2679 Check_Scalar_Type;
2680 Resolve (E1, P_Base_Type);
2681 Resolve (E2, P_Base_Type);
2682 Set_Etype (N, P_Base_Type);
2684 -- Check for comparison on unordered enumeration type
2686 if Bad_Unordered_Enumeration_Reference (N, P_Base_Type) then
2687 Error_Msg_Sloc := Sloc (P_Base_Type);
2688 Error_Msg_NE
2689 ("comparison on unordered enumeration type& declared#?U?",
2690 N, P_Base_Type);
2691 end if;
2692 end Min_Max;
2694 ------------------------
2695 -- Standard_Attribute --
2696 ------------------------
2698 procedure Standard_Attribute (Val : Int) is
2699 begin
2700 Check_Standard_Prefix;
2701 Rewrite (N, Make_Integer_Literal (Loc, Val));
2702 Analyze (N);
2703 Set_Is_Static_Expression (N, True);
2704 end Standard_Attribute;
2706 --------------------
2707 -- Uneval_Old_Msg --
2708 --------------------
2710 procedure Uneval_Old_Msg is
2711 Uneval_Old_Setting : Character;
2712 Prag : Node_Id;
2714 begin
2715 -- If from aspect, then Uneval_Old_Setting comes from flags in the
2716 -- N_Aspect_Specification node that corresponds to the attribute.
2718 -- First find the pragma in which we appear (note that at this stage,
2719 -- even if we appeared originally within an aspect specification, we
2720 -- are now within the corresponding pragma).
2722 Prag := N;
2723 loop
2724 Prag := Parent (Prag);
2725 exit when No (Prag) or else Nkind (Prag) = N_Pragma;
2726 end loop;
2728 if Present (Prag) then
2729 if Uneval_Old_Accept (Prag) then
2730 Uneval_Old_Setting := 'A';
2731 elsif Uneval_Old_Warn (Prag) then
2732 Uneval_Old_Setting := 'W';
2733 else
2734 Uneval_Old_Setting := 'E';
2735 end if;
2737 -- If we did not find the pragma, that's odd, just use the setting
2738 -- from Opt.Uneval_Old. Perhaps this is due to a previous error?
2740 else
2741 Uneval_Old_Setting := Opt.Uneval_Old;
2742 end if;
2744 -- Processing depends on the setting of Uneval_Old
2746 case Uneval_Old_Setting is
2747 when 'E' =>
2748 Error_Attr_P
2749 ("prefix of attribute % that is potentially "
2750 & "unevaluated must denote an entity");
2752 when 'W' =>
2753 Error_Msg_Name_1 := Aname;
2754 Error_Msg_F
2755 ("??prefix of attribute % appears in potentially "
2756 & "unevaluated context, exception may be raised", P);
2758 when 'A' =>
2759 null;
2761 when others =>
2762 raise Program_Error;
2763 end case;
2764 end Uneval_Old_Msg;
2766 -------------------------
2767 -- Unexpected Argument --
2768 -------------------------
2770 procedure Unexpected_Argument (En : Node_Id) is
2771 begin
2772 Error_Attr ("unexpected argument for % attribute", En);
2773 end Unexpected_Argument;
2775 -------------------------------------------------
2776 -- Validate_Non_Static_Attribute_Function_Call --
2777 -------------------------------------------------
2779 -- This function should be moved to Sem_Dist ???
2781 procedure Validate_Non_Static_Attribute_Function_Call is
2782 begin
2783 if In_Preelaborated_Unit
2784 and then not In_Subprogram_Or_Concurrent_Unit
2785 then
2786 Flag_Non_Static_Expr
2787 ("non-static function call in preelaborated unit!", N);
2788 end if;
2789 end Validate_Non_Static_Attribute_Function_Call;
2791 -- Start of processing for Analyze_Attribute
2793 begin
2794 -- Immediate return if unrecognized attribute (already diagnosed by
2795 -- parser, so there is nothing more that we need to do).
2797 if not Is_Attribute_Name (Aname) then
2798 raise Bad_Attribute;
2799 end if;
2801 Check_Restriction_No_Use_Of_Attribute (N);
2803 -- Deal with Ada 83 issues
2805 if Comes_From_Source (N) then
2806 if not Attribute_83 (Attr_Id) then
2807 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
2808 Error_Msg_Name_1 := Aname;
2809 Error_Msg_N ("(Ada 83) attribute% is not standard??", N);
2810 end if;
2812 if Attribute_Impl_Def (Attr_Id) then
2813 Check_Restriction (No_Implementation_Attributes, N);
2814 end if;
2815 end if;
2816 end if;
2818 -- Deal with Ada 2005 attributes that are implementation attributes
2819 -- because they appear in a version of Ada before Ada 2005, and
2820 -- similarly for Ada 2012 attributes appearing in an earlier version.
2822 if (Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005)
2823 or else
2824 (Attribute_12 (Attr_Id) and then Ada_Version < Ada_2012)
2825 then
2826 Check_Restriction (No_Implementation_Attributes, N);
2827 end if;
2829 -- Remote access to subprogram type access attribute reference needs
2830 -- unanalyzed copy for tree transformation. The analyzed copy is used
2831 -- for its semantic information (whether prefix is a remote subprogram
2832 -- name), the unanalyzed copy is used to construct new subtree rooted
2833 -- with N_Aggregate which represents a fat pointer aggregate.
2835 if Aname = Name_Access then
2836 Discard_Node (Copy_Separate_Tree (N));
2837 end if;
2839 -- Analyze prefix and exit if error in analysis. If the prefix is an
2840 -- incomplete type, use full view if available. Note that there are
2841 -- some attributes for which we do not analyze the prefix, since the
2842 -- prefix is not a normal name, or else needs special handling.
2844 if Aname /= Name_Elab_Body and then
2845 Aname /= Name_Elab_Spec and then
2846 Aname /= Name_Elab_Subp_Body and then
2847 Aname /= Name_Enabled and then
2848 Aname /= Name_Old
2849 then
2850 Analyze (P);
2851 P_Type := Etype (P);
2853 if Is_Entity_Name (P)
2854 and then Present (Entity (P))
2855 and then Is_Type (Entity (P))
2856 then
2857 if Ekind (Entity (P)) = E_Incomplete_Type then
2858 P_Type := Get_Full_View (P_Type);
2859 Set_Entity (P, P_Type);
2860 Set_Etype (P, P_Type);
2862 elsif Entity (P) = Current_Scope
2863 and then Is_Record_Type (Entity (P))
2864 then
2865 -- Use of current instance within the type. Verify that if the
2866 -- attribute appears within a constraint, it yields an access
2867 -- type, other uses are illegal.
2869 declare
2870 Par : Node_Id;
2872 begin
2873 Par := Parent (N);
2874 while Present (Par)
2875 and then Nkind (Parent (Par)) /= N_Component_Definition
2876 loop
2877 Par := Parent (Par);
2878 end loop;
2880 if Present (Par)
2881 and then Nkind (Par) = N_Subtype_Indication
2882 then
2883 if Attr_Id /= Attribute_Access
2884 and then Attr_Id /= Attribute_Unchecked_Access
2885 and then Attr_Id /= Attribute_Unrestricted_Access
2886 then
2887 Error_Msg_N
2888 ("in a constraint the current instance can only "
2889 & "be used with an access attribute", N);
2890 end if;
2891 end if;
2892 end;
2893 end if;
2894 end if;
2896 if P_Type = Any_Type then
2897 raise Bad_Attribute;
2898 end if;
2900 P_Base_Type := Base_Type (P_Type);
2901 end if;
2903 -- Analyze expressions that may be present, exiting if an error occurs
2905 if No (Exprs) then
2906 E1 := Empty;
2907 E2 := Empty;
2909 else
2910 E1 := First (Exprs);
2912 -- Skip analysis for case of Restriction_Set, we do not expect
2913 -- the argument to be analyzed in this case.
2915 if Aname /= Name_Restriction_Set then
2916 Analyze (E1);
2918 -- Check for missing/bad expression (result of previous error)
2920 if No (E1) or else Etype (E1) = Any_Type then
2921 raise Bad_Attribute;
2922 end if;
2923 end if;
2925 E2 := Next (E1);
2927 if Present (E2) then
2928 Analyze (E2);
2930 if Etype (E2) = Any_Type then
2931 raise Bad_Attribute;
2932 end if;
2934 if Present (Next (E2)) then
2935 Unexpected_Argument (Next (E2));
2936 end if;
2937 end if;
2938 end if;
2940 -- Cases where prefix must be resolvable by itself
2942 if Is_Overloaded (P)
2943 and then Aname /= Name_Access
2944 and then Aname /= Name_Address
2945 and then Aname /= Name_Code_Address
2946 and then Aname /= Name_Result
2947 and then Aname /= Name_Unchecked_Access
2948 then
2949 -- The prefix must be resolvable by itself, without reference to the
2950 -- attribute. One case that requires special handling is a prefix
2951 -- that is a function name, where one interpretation may be a
2952 -- parameterless call. Entry attributes are handled specially below.
2954 if Is_Entity_Name (P)
2955 and then not Nam_In (Aname, Name_Count, Name_Caller)
2956 then
2957 Check_Parameterless_Call (P);
2958 end if;
2960 if Is_Overloaded (P) then
2962 -- Ada 2005 (AI-345): Since protected and task types have
2963 -- primitive entry wrappers, the attributes Count, and Caller
2964 -- require a context check
2966 if Nam_In (Aname, Name_Count, Name_Caller) then
2967 declare
2968 Count : Natural := 0;
2969 I : Interp_Index;
2970 It : Interp;
2972 begin
2973 Get_First_Interp (P, I, It);
2974 while Present (It.Nam) loop
2975 if Comes_From_Source (It.Nam) then
2976 Count := Count + 1;
2977 else
2978 Remove_Interp (I);
2979 end if;
2981 Get_Next_Interp (I, It);
2982 end loop;
2984 if Count > 1 then
2985 Error_Attr ("ambiguous prefix for % attribute", P);
2986 else
2987 Set_Is_Overloaded (P, False);
2988 end if;
2989 end;
2991 else
2992 Error_Attr ("ambiguous prefix for % attribute", P);
2993 end if;
2994 end if;
2995 end if;
2997 -- In SPARK, attributes of private types are only allowed if the full
2998 -- type declaration is visible.
3000 -- Note: the check for Present (Entity (P)) defends against some error
3001 -- conditions where the Entity field is not set.
3003 if Is_Entity_Name (P) and then Present (Entity (P))
3004 and then Is_Type (Entity (P))
3005 and then Is_Private_Type (P_Type)
3006 and then not In_Open_Scopes (Scope (P_Type))
3007 and then not In_Spec_Expression
3008 then
3009 Check_SPARK_05_Restriction ("invisible attribute of type", N);
3010 end if;
3012 -- Remaining processing depends on attribute
3014 case Attr_Id is
3016 -- Attributes related to Ada 2012 iterators. Attribute specifications
3017 -- exist for these, but they cannot be queried.
3019 when Attribute_Constant_Indexing
3020 | Attribute_Default_Iterator
3021 | Attribute_Implicit_Dereference
3022 | Attribute_Iterator_Element
3023 | Attribute_Iterable
3024 | Attribute_Variable_Indexing
3026 Error_Msg_N ("illegal attribute", N);
3028 -- Internal attributes used to deal with Ada 2012 delayed aspects. These
3029 -- were already rejected by the parser. Thus they shouldn't appear here.
3031 when Internal_Attribute_Id =>
3032 raise Program_Error;
3034 ------------------
3035 -- Abort_Signal --
3036 ------------------
3038 when Attribute_Abort_Signal =>
3039 Check_Standard_Prefix;
3040 Rewrite (N, New_Occurrence_Of (Stand.Abort_Signal, Loc));
3041 Analyze (N);
3043 ------------
3044 -- Access --
3045 ------------
3047 when Attribute_Access =>
3048 Analyze_Access_Attribute;
3049 Check_Not_Incomplete_Type;
3051 -------------
3052 -- Address --
3053 -------------
3055 when Attribute_Address =>
3056 Check_E0;
3057 Address_Checks;
3058 Check_Not_Incomplete_Type;
3059 Set_Etype (N, RTE (RE_Address));
3061 ------------------
3062 -- Address_Size --
3063 ------------------
3065 when Attribute_Address_Size =>
3066 Standard_Attribute (System_Address_Size);
3068 --------------
3069 -- Adjacent --
3070 --------------
3072 when Attribute_Adjacent =>
3073 Check_Floating_Point_Type_2;
3074 Set_Etype (N, P_Base_Type);
3075 Resolve (E1, P_Base_Type);
3076 Resolve (E2, P_Base_Type);
3078 ---------
3079 -- Aft --
3080 ---------
3082 when Attribute_Aft =>
3083 Check_Fixed_Point_Type_0;
3084 Set_Etype (N, Universal_Integer);
3086 ---------------
3087 -- Alignment --
3088 ---------------
3090 when Attribute_Alignment =>
3092 -- Don't we need more checking here, cf Size ???
3094 Check_E0;
3095 Check_Not_Incomplete_Type;
3096 Check_Not_CPP_Type;
3097 Set_Etype (N, Universal_Integer);
3099 ---------------
3100 -- Asm_Input --
3101 ---------------
3103 when Attribute_Asm_Input =>
3104 Check_Asm_Attribute;
3106 -- The back end may need to take the address of E2
3108 if Is_Entity_Name (E2) then
3109 Set_Address_Taken (Entity (E2));
3110 end if;
3112 Set_Etype (N, RTE (RE_Asm_Input_Operand));
3114 ----------------
3115 -- Asm_Output --
3116 ----------------
3118 when Attribute_Asm_Output =>
3119 Check_Asm_Attribute;
3121 if Etype (E2) = Any_Type then
3122 return;
3124 elsif Aname = Name_Asm_Output then
3125 if not Is_Variable (E2) then
3126 Error_Attr
3127 ("second argument for Asm_Output is not variable", E2);
3128 end if;
3129 end if;
3131 Note_Possible_Modification (E2, Sure => True);
3133 -- The back end may need to take the address of E2
3135 if Is_Entity_Name (E2) then
3136 Set_Address_Taken (Entity (E2));
3137 end if;
3139 Set_Etype (N, RTE (RE_Asm_Output_Operand));
3141 -----------------------------
3142 -- Atomic_Always_Lock_Free --
3143 -----------------------------
3145 when Attribute_Atomic_Always_Lock_Free =>
3146 Check_E0;
3147 Check_Type;
3148 Set_Etype (N, Standard_Boolean);
3150 ----------
3151 -- Base --
3152 ----------
3154 -- Note: when the base attribute appears in the context of a subtype
3155 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
3156 -- the following circuit.
3158 when Attribute_Base => Base : declare
3159 Typ : Entity_Id;
3161 begin
3162 Check_E0;
3163 Find_Type (P);
3164 Typ := Entity (P);
3166 if Ada_Version >= Ada_95
3167 and then not Is_Scalar_Type (Typ)
3168 and then not Is_Generic_Type (Typ)
3169 then
3170 Error_Attr_P ("prefix of Base attribute must be scalar type");
3172 elsif Sloc (Typ) = Standard_Location
3173 and then Base_Type (Typ) = Typ
3174 and then Warn_On_Redundant_Constructs
3175 then
3176 Error_Msg_NE -- CODEFIX
3177 ("?r?redundant attribute, & is its own base type", N, Typ);
3178 end if;
3180 if Nkind (Parent (N)) /= N_Attribute_Reference then
3181 Error_Msg_Name_1 := Aname;
3182 Check_SPARK_05_Restriction
3183 ("attribute% is only allowed as prefix of another attribute", P);
3184 end if;
3186 Set_Etype (N, Base_Type (Entity (P)));
3187 Set_Entity (N, Base_Type (Entity (P)));
3188 Rewrite (N, New_Occurrence_Of (Entity (N), Loc));
3189 Analyze (N);
3190 end Base;
3192 ---------
3193 -- Bit --
3194 ---------
3196 when Attribute_Bit =>
3197 Check_E0;
3199 if not Is_Object_Reference (P) then
3200 Error_Attr_P ("prefix for % attribute must be object");
3202 -- What about the access object cases ???
3204 else
3205 null;
3206 end if;
3208 Set_Etype (N, Universal_Integer);
3210 ---------------
3211 -- Bit_Order --
3212 ---------------
3214 when Attribute_Bit_Order =>
3215 Check_E0;
3216 Check_Type;
3218 if not Is_Record_Type (P_Type) then
3219 Error_Attr_P ("prefix of % attribute must be record type");
3220 end if;
3222 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
3223 Rewrite (N,
3224 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
3225 else
3226 Rewrite (N,
3227 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
3228 end if;
3230 Set_Etype (N, RTE (RE_Bit_Order));
3231 Resolve (N);
3233 -- Reset incorrect indication of staticness
3235 Set_Is_Static_Expression (N, False);
3237 ------------------
3238 -- Bit_Position --
3239 ------------------
3241 -- Note: in generated code, we can have a Bit_Position attribute
3242 -- applied to a (naked) record component (i.e. the prefix is an
3243 -- identifier that references an E_Component or E_Discriminant
3244 -- entity directly, and this is interpreted as expected by Gigi.
3245 -- The following code will not tolerate such usage, but when the
3246 -- expander creates this special case, it marks it as analyzed
3247 -- immediately and sets an appropriate type.
3249 when Attribute_Bit_Position =>
3250 if Comes_From_Source (N) then
3251 Check_Component;
3252 end if;
3254 Set_Etype (N, Universal_Integer);
3256 ------------------
3257 -- Body_Version --
3258 ------------------
3260 when Attribute_Body_Version =>
3261 Check_E0;
3262 Check_Program_Unit;
3263 Set_Etype (N, RTE (RE_Version_String));
3265 --------------
3266 -- Callable --
3267 --------------
3269 when Attribute_Callable =>
3270 Check_E0;
3271 Set_Etype (N, Standard_Boolean);
3272 Check_Task_Prefix;
3274 ------------
3275 -- Caller --
3276 ------------
3278 when Attribute_Caller => Caller : declare
3279 Ent : Entity_Id;
3280 S : Entity_Id;
3282 begin
3283 Check_E0;
3285 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
3286 Ent := Entity (P);
3288 if not Is_Entry (Ent) then
3289 Error_Attr ("invalid entry name", N);
3290 end if;
3292 else
3293 Error_Attr ("invalid entry name", N);
3294 return;
3295 end if;
3297 for J in reverse 0 .. Scope_Stack.Last loop
3298 S := Scope_Stack.Table (J).Entity;
3300 if S = Scope (Ent) then
3301 Error_Attr ("Caller must appear in matching accept or body", N);
3302 elsif S = Ent then
3303 exit;
3304 end if;
3305 end loop;
3307 Set_Etype (N, RTE (RO_AT_Task_Id));
3308 end Caller;
3310 -------------
3311 -- Ceiling --
3312 -------------
3314 when Attribute_Ceiling =>
3315 Check_Floating_Point_Type_1;
3316 Set_Etype (N, P_Base_Type);
3317 Resolve (E1, P_Base_Type);
3319 -----------
3320 -- Class --
3321 -----------
3323 when Attribute_Class =>
3324 Check_Restriction (No_Dispatch, N);
3325 Check_E0;
3326 Find_Type (N);
3328 -- Applying Class to untagged incomplete type is obsolescent in Ada
3329 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
3330 -- this flag gets set by Find_Type in this situation.
3332 if Restriction_Check_Required (No_Obsolescent_Features)
3333 and then Ada_Version >= Ada_2005
3334 and then Ekind (P_Type) = E_Incomplete_Type
3335 then
3336 declare
3337 DN : constant Node_Id := Declaration_Node (P_Type);
3338 begin
3339 if Nkind (DN) = N_Incomplete_Type_Declaration
3340 and then not Tagged_Present (DN)
3341 then
3342 Check_Restriction (No_Obsolescent_Features, P);
3343 end if;
3344 end;
3345 end if;
3347 ------------------
3348 -- Code_Address --
3349 ------------------
3351 when Attribute_Code_Address =>
3352 Check_E0;
3354 if Nkind (P) = N_Attribute_Reference
3355 and then Nam_In (Attribute_Name (P), Name_Elab_Body, Name_Elab_Spec)
3356 then
3357 null;
3359 elsif not Is_Entity_Name (P)
3360 or else (Ekind (Entity (P)) /= E_Function
3361 and then
3362 Ekind (Entity (P)) /= E_Procedure)
3363 then
3364 Error_Attr ("invalid prefix for % attribute", P);
3365 Set_Address_Taken (Entity (P));
3367 -- Issue an error if the prefix denotes an eliminated subprogram
3369 else
3370 Check_For_Eliminated_Subprogram (P, Entity (P));
3371 end if;
3373 Set_Etype (N, RTE (RE_Address));
3375 ----------------------
3376 -- Compiler_Version --
3377 ----------------------
3379 when Attribute_Compiler_Version =>
3380 Check_E0;
3381 Check_Standard_Prefix;
3382 Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
3383 Analyze_And_Resolve (N, Standard_String);
3384 Set_Is_Static_Expression (N, True);
3386 --------------------
3387 -- Component_Size --
3388 --------------------
3390 when Attribute_Component_Size =>
3391 Check_E0;
3392 Set_Etype (N, Universal_Integer);
3394 -- Note: unlike other array attributes, unconstrained arrays are OK
3396 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
3397 null;
3398 else
3399 Check_Array_Type;
3400 end if;
3402 -------------
3403 -- Compose --
3404 -------------
3406 when Attribute_Compose =>
3407 Check_Floating_Point_Type_2;
3408 Set_Etype (N, P_Base_Type);
3409 Resolve (E1, P_Base_Type);
3410 Resolve (E2, Any_Integer);
3412 -----------------
3413 -- Constrained --
3414 -----------------
3416 when Attribute_Constrained =>
3417 Check_E0;
3418 Set_Etype (N, Standard_Boolean);
3420 -- Case from RM J.4(2) of constrained applied to private type
3422 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
3423 Check_Restriction (No_Obsolescent_Features, P);
3425 if Warn_On_Obsolescent_Feature then
3426 Error_Msg_N
3427 ("constrained for private type is an obsolescent feature "
3428 & "(RM J.4)?j?", N);
3429 end if;
3431 -- If we are within an instance, the attribute must be legal
3432 -- because it was valid in the generic unit. Ditto if this is
3433 -- an inlining of a function declared in an instance.
3435 if In_Instance or else In_Inlined_Body then
3436 return;
3438 -- For sure OK if we have a real private type itself, but must
3439 -- be completed, cannot apply Constrained to incomplete type.
3441 elsif Is_Private_Type (Entity (P)) then
3443 -- Note: this is one of the Annex J features that does not
3444 -- generate a warning from -gnatwj, since in fact it seems
3445 -- very useful, and is used in the GNAT runtime.
3447 Check_Not_Incomplete_Type;
3448 return;
3449 end if;
3451 -- Normal (non-obsolescent case) of application to object of
3452 -- a discriminated type.
3454 else
3455 Check_Object_Reference (P);
3457 -- If N does not come from source, then we allow the
3458 -- the attribute prefix to be of a private type whose
3459 -- full type has discriminants. This occurs in cases
3460 -- involving expanded calls to stream attributes.
3462 if not Comes_From_Source (N) then
3463 P_Type := Underlying_Type (P_Type);
3464 end if;
3466 -- Must have discriminants or be an access type designating a type
3467 -- with discriminants. If it is a class-wide type it has unknown
3468 -- discriminants.
3470 if Has_Discriminants (P_Type)
3471 or else Has_Unknown_Discriminants (P_Type)
3472 or else
3473 (Is_Access_Type (P_Type)
3474 and then Has_Discriminants (Designated_Type (P_Type)))
3475 then
3476 return;
3478 -- The rule given in 3.7.2 is part of static semantics, but the
3479 -- intent is clearly that it be treated as a legality rule, and
3480 -- rechecked in the visible part of an instance. Nevertheless
3481 -- the intent also seems to be it should legally apply to the
3482 -- actual of a formal with unknown discriminants, regardless of
3483 -- whether the actual has discriminants, in which case the value
3484 -- of the attribute is determined using the J.4 rules. This choice
3485 -- seems the most useful, and is compatible with existing tests.
3487 elsif In_Instance then
3488 return;
3490 -- Also allow an object of a generic type if extensions allowed
3491 -- and allow this for any type at all. (this may be obsolete ???)
3493 elsif (Is_Generic_Type (P_Type)
3494 or else Is_Generic_Actual_Type (P_Type))
3495 and then Extensions_Allowed
3496 then
3497 return;
3498 end if;
3499 end if;
3501 -- Fall through if bad prefix
3503 Error_Attr_P
3504 ("prefix of % attribute must be object of discriminated type");
3506 ---------------
3507 -- Copy_Sign --
3508 ---------------
3510 when Attribute_Copy_Sign =>
3511 Check_Floating_Point_Type_2;
3512 Set_Etype (N, P_Base_Type);
3513 Resolve (E1, P_Base_Type);
3514 Resolve (E2, P_Base_Type);
3516 -----------
3517 -- Count --
3518 -----------
3520 when Attribute_Count => Count : declare
3521 Ent : Entity_Id;
3522 S : Entity_Id;
3523 Tsk : Entity_Id;
3525 begin
3526 Check_E0;
3528 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
3529 Ent := Entity (P);
3531 if Ekind (Ent) /= E_Entry then
3532 Error_Attr ("invalid entry name", N);
3533 end if;
3535 elsif Nkind (P) = N_Indexed_Component then
3536 if not Is_Entity_Name (Prefix (P))
3537 or else No (Entity (Prefix (P)))
3538 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
3539 then
3540 if Nkind (Prefix (P)) = N_Selected_Component
3541 and then Present (Entity (Selector_Name (Prefix (P))))
3542 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
3543 E_Entry_Family
3544 then
3545 Error_Attr
3546 ("attribute % must apply to entry of current task", P);
3548 else
3549 Error_Attr ("invalid entry family name", P);
3550 end if;
3551 return;
3553 else
3554 Ent := Entity (Prefix (P));
3555 end if;
3557 elsif Nkind (P) = N_Selected_Component
3558 and then Present (Entity (Selector_Name (P)))
3559 and then Ekind (Entity (Selector_Name (P))) = E_Entry
3560 then
3561 Error_Attr
3562 ("attribute % must apply to entry of current task", P);
3564 else
3565 Error_Attr ("invalid entry name", N);
3566 return;
3567 end if;
3569 for J in reverse 0 .. Scope_Stack.Last loop
3570 S := Scope_Stack.Table (J).Entity;
3572 if S = Scope (Ent) then
3573 if Nkind (P) = N_Expanded_Name then
3574 Tsk := Entity (Prefix (P));
3576 -- The prefix denotes either the task type, or else a
3577 -- single task whose task type is being analyzed.
3579 if (Is_Type (Tsk) and then Tsk = S)
3580 or else (not Is_Type (Tsk)
3581 and then Etype (Tsk) = S
3582 and then not (Comes_From_Source (S)))
3583 then
3584 null;
3585 else
3586 Error_Attr
3587 ("Attribute % must apply to entry of current task", N);
3588 end if;
3589 end if;
3591 exit;
3593 elsif Ekind (Scope (Ent)) in Task_Kind
3594 and then not Ekind_In (S, E_Block,
3595 E_Entry,
3596 E_Entry_Family,
3597 E_Loop)
3598 then
3599 Error_Attr ("Attribute % cannot appear in inner unit", N);
3601 elsif Ekind (Scope (Ent)) = E_Protected_Type
3602 and then not Has_Completion (Scope (Ent))
3603 then
3604 Error_Attr ("attribute % can only be used inside body", N);
3605 end if;
3606 end loop;
3608 if Is_Overloaded (P) then
3609 declare
3610 Index : Interp_Index;
3611 It : Interp;
3613 begin
3614 Get_First_Interp (P, Index, It);
3615 while Present (It.Nam) loop
3616 if It.Nam = Ent then
3617 null;
3619 -- Ada 2005 (AI-345): Do not consider primitive entry
3620 -- wrappers generated for task or protected types.
3622 elsif Ada_Version >= Ada_2005
3623 and then not Comes_From_Source (It.Nam)
3624 then
3625 null;
3627 else
3628 Error_Attr ("ambiguous entry name", N);
3629 end if;
3631 Get_Next_Interp (Index, It);
3632 end loop;
3633 end;
3634 end if;
3636 Set_Etype (N, Universal_Integer);
3637 end Count;
3639 -----------------------
3640 -- Default_Bit_Order --
3641 -----------------------
3643 when Attribute_Default_Bit_Order => Default_Bit_Order : declare
3644 Target_Default_Bit_Order : System.Bit_Order;
3646 begin
3647 Check_Standard_Prefix;
3649 if Bytes_Big_Endian then
3650 Target_Default_Bit_Order := System.High_Order_First;
3651 else
3652 Target_Default_Bit_Order := System.Low_Order_First;
3653 end if;
3655 Rewrite (N,
3656 Make_Integer_Literal (Loc,
3657 UI_From_Int (System.Bit_Order'Pos (Target_Default_Bit_Order))));
3659 Set_Etype (N, Universal_Integer);
3660 Set_Is_Static_Expression (N);
3661 end Default_Bit_Order;
3663 ----------------------------------
3664 -- Default_Scalar_Storage_Order --
3665 ----------------------------------
3667 when Attribute_Default_Scalar_Storage_Order => Default_SSO : declare
3668 RE_Default_SSO : RE_Id;
3670 begin
3671 Check_Standard_Prefix;
3673 case Opt.Default_SSO is
3674 when ' ' =>
3675 if Bytes_Big_Endian then
3676 RE_Default_SSO := RE_High_Order_First;
3677 else
3678 RE_Default_SSO := RE_Low_Order_First;
3679 end if;
3681 when 'H' =>
3682 RE_Default_SSO := RE_High_Order_First;
3684 when 'L' =>
3685 RE_Default_SSO := RE_Low_Order_First;
3687 when others =>
3688 raise Program_Error;
3689 end case;
3691 Rewrite (N, New_Occurrence_Of (RTE (RE_Default_SSO), Loc));
3692 end Default_SSO;
3694 --------------
3695 -- Definite --
3696 --------------
3698 when Attribute_Definite =>
3699 Legal_Formal_Attribute;
3701 -----------
3702 -- Delta --
3703 -----------
3705 when Attribute_Delta =>
3706 Check_Fixed_Point_Type_0;
3707 Set_Etype (N, Universal_Real);
3709 ------------
3710 -- Denorm --
3711 ------------
3713 when Attribute_Denorm =>
3714 Check_Floating_Point_Type_0;
3715 Set_Etype (N, Standard_Boolean);
3717 -----------
3718 -- Deref --
3719 -----------
3721 when Attribute_Deref =>
3722 Check_Type;
3723 Check_E1;
3724 Resolve (E1, RTE (RE_Address));
3725 Set_Etype (N, P_Type);
3727 ---------------------
3728 -- Descriptor_Size --
3729 ---------------------
3731 when Attribute_Descriptor_Size =>
3732 Check_E0;
3734 if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then
3735 Error_Attr_P ("prefix of attribute % must denote a type");
3736 end if;
3738 Set_Etype (N, Universal_Integer);
3740 ------------
3741 -- Digits --
3742 ------------
3744 when Attribute_Digits =>
3745 Check_E0;
3746 Check_Type;
3748 if not Is_Floating_Point_Type (P_Type)
3749 and then not Is_Decimal_Fixed_Point_Type (P_Type)
3750 then
3751 Error_Attr_P
3752 ("prefix of % attribute must be float or decimal type");
3753 end if;
3755 Set_Etype (N, Universal_Integer);
3757 ---------------
3758 -- Elab_Body --
3759 ---------------
3761 -- Also handles processing for Elab_Spec and Elab_Subp_Body
3763 when Attribute_Elab_Body
3764 | Attribute_Elab_Spec
3765 | Attribute_Elab_Subp_Body
3767 Check_E0;
3768 Check_Unit_Name (P);
3769 Set_Etype (N, Standard_Void_Type);
3771 -- We have to manually call the expander in this case to get
3772 -- the necessary expansion (normally attributes that return
3773 -- entities are not expanded).
3775 Expand (N);
3777 ---------------
3778 -- Elab_Spec --
3779 ---------------
3781 -- Shares processing with Elab_Body
3783 ----------------
3784 -- Elaborated --
3785 ----------------
3787 when Attribute_Elaborated =>
3788 Check_E0;
3789 Check_Unit_Name (P);
3790 Set_Etype (N, Standard_Boolean);
3792 ----------
3793 -- Emax --
3794 ----------
3796 when Attribute_Emax =>
3797 Check_Floating_Point_Type_0;
3798 Set_Etype (N, Universal_Integer);
3800 -------------
3801 -- Enabled --
3802 -------------
3804 when Attribute_Enabled =>
3805 Check_Either_E0_Or_E1;
3807 if Present (E1) then
3808 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
3809 Error_Msg_N ("entity name expected for Enabled attribute", E1);
3810 E1 := Empty;
3811 end if;
3812 end if;
3814 if Nkind (P) /= N_Identifier then
3815 Error_Msg_N ("identifier expected (check name)", P);
3816 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
3817 Error_Msg_N ("& is not a recognized check name", P);
3818 end if;
3820 Set_Etype (N, Standard_Boolean);
3822 --------------
3823 -- Enum_Rep --
3824 --------------
3826 when Attribute_Enum_Rep =>
3828 -- T'Enum_Rep (X) case
3830 if Present (E1) then
3831 Check_E1;
3832 Check_Discrete_Type;
3833 Resolve (E1, P_Base_Type);
3835 -- X'Enum_Rep case. X must be an object or enumeration literal, and
3836 -- it must be of a discrete type.
3838 elsif not
3839 ((Is_Object_Reference (P)
3840 or else
3841 (Is_Entity_Name (P)
3842 and then Ekind (Entity (P)) = E_Enumeration_Literal))
3843 and then Is_Discrete_Type (Etype (P)))
3844 then
3845 Error_Attr_P ("prefix of % attribute must be discrete object");
3846 end if;
3848 Set_Etype (N, Universal_Integer);
3850 --------------
3851 -- Enum_Val --
3852 --------------
3854 when Attribute_Enum_Val =>
3855 Check_E1;
3856 Check_Type;
3858 if not Is_Enumeration_Type (P_Type) then
3859 Error_Attr_P ("prefix of % attribute must be enumeration type");
3860 end if;
3862 -- If the enumeration type has a standard representation, the effect
3863 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3865 if not Has_Non_Standard_Rep (P_Base_Type) then
3866 Rewrite (N,
3867 Make_Attribute_Reference (Loc,
3868 Prefix => Relocate_Node (Prefix (N)),
3869 Attribute_Name => Name_Val,
3870 Expressions => New_List (Relocate_Node (E1))));
3871 Analyze_And_Resolve (N, P_Base_Type);
3873 -- Non-standard representation case (enumeration with holes)
3875 else
3876 Check_Enum_Image;
3877 Resolve (E1, Any_Integer);
3878 Set_Etype (N, P_Base_Type);
3879 end if;
3881 -------------
3882 -- Epsilon --
3883 -------------
3885 when Attribute_Epsilon =>
3886 Check_Floating_Point_Type_0;
3887 Set_Etype (N, Universal_Real);
3889 --------------
3890 -- Exponent --
3891 --------------
3893 when Attribute_Exponent =>
3894 Check_Floating_Point_Type_1;
3895 Set_Etype (N, Universal_Integer);
3896 Resolve (E1, P_Base_Type);
3898 ------------------
3899 -- External_Tag --
3900 ------------------
3902 when Attribute_External_Tag =>
3903 Check_E0;
3904 Check_Type;
3906 Set_Etype (N, Standard_String);
3908 if not Is_Tagged_Type (P_Type) then
3909 Error_Attr_P ("prefix of % attribute must be tagged");
3910 end if;
3912 ---------------
3913 -- Fast_Math --
3914 ---------------
3916 when Attribute_Fast_Math =>
3917 Check_Standard_Prefix;
3918 Rewrite (N, New_Occurrence_Of (Boolean_Literals (Fast_Math), Loc));
3920 -----------------------
3921 -- Finalization_Size --
3922 -----------------------
3924 when Attribute_Finalization_Size =>
3925 Check_E0;
3927 -- The prefix denotes an object
3929 if Is_Object_Reference (P) then
3930 Check_Object_Reference (P);
3932 -- The prefix denotes a type
3934 elsif Is_Entity_Name (P) and then Is_Type (Entity (P)) then
3935 Check_Type;
3936 Check_Not_Incomplete_Type;
3938 -- Attribute 'Finalization_Size is not defined for class-wide
3939 -- types because it is not possible to know statically whether
3940 -- a definite type will have controlled components or not.
3942 if Is_Class_Wide_Type (Etype (P)) then
3943 Error_Attr_P
3944 ("prefix of % attribute cannot denote a class-wide type");
3945 end if;
3947 -- The prefix denotes an illegal construct
3949 else
3950 Error_Attr_P
3951 ("prefix of % attribute must be a definite type or an object");
3952 end if;
3954 Set_Etype (N, Universal_Integer);
3956 -----------
3957 -- First --
3958 -----------
3960 when Attribute_First =>
3961 Check_Array_Or_Scalar_Type;
3962 Bad_Attribute_For_Predicate;
3964 ---------------
3965 -- First_Bit --
3966 ---------------
3968 when Attribute_First_Bit =>
3969 Check_Component;
3970 Set_Etype (N, Universal_Integer);
3972 -----------------
3973 -- First_Valid --
3974 -----------------
3976 when Attribute_First_Valid =>
3977 Check_First_Last_Valid;
3978 Set_Etype (N, P_Type);
3980 -----------------
3981 -- Fixed_Value --
3982 -----------------
3984 when Attribute_Fixed_Value =>
3985 Check_E1;
3986 Check_Fixed_Point_Type;
3987 Resolve (E1, Any_Integer);
3988 Set_Etype (N, P_Base_Type);
3990 -----------
3991 -- Floor --
3992 -----------
3994 when Attribute_Floor =>
3995 Check_Floating_Point_Type_1;
3996 Set_Etype (N, P_Base_Type);
3997 Resolve (E1, P_Base_Type);
3999 ----------
4000 -- Fore --
4001 ----------
4003 when Attribute_Fore =>
4004 Check_Fixed_Point_Type_0;
4005 Set_Etype (N, Universal_Integer);
4007 --------------
4008 -- Fraction --
4009 --------------
4011 when Attribute_Fraction =>
4012 Check_Floating_Point_Type_1;
4013 Set_Etype (N, P_Base_Type);
4014 Resolve (E1, P_Base_Type);
4016 --------------
4017 -- From_Any --
4018 --------------
4020 when Attribute_From_Any =>
4021 Check_E1;
4022 Check_PolyORB_Attribute;
4023 Set_Etype (N, P_Base_Type);
4025 -----------------------
4026 -- Has_Access_Values --
4027 -----------------------
4029 when Attribute_Has_Access_Values =>
4030 Check_Type;
4031 Check_E0;
4032 Set_Etype (N, Standard_Boolean);
4034 ----------------------
4035 -- Has_Same_Storage --
4036 ----------------------
4038 when Attribute_Has_Same_Storage =>
4039 Check_E1;
4041 -- The arguments must be objects of any type
4043 Analyze_And_Resolve (P);
4044 Analyze_And_Resolve (E1);
4045 Check_Object_Reference (P);
4046 Check_Object_Reference (E1);
4047 Set_Etype (N, Standard_Boolean);
4049 -----------------------
4050 -- Has_Tagged_Values --
4051 -----------------------
4053 when Attribute_Has_Tagged_Values =>
4054 Check_Type;
4055 Check_E0;
4056 Set_Etype (N, Standard_Boolean);
4058 -----------------------
4059 -- Has_Discriminants --
4060 -----------------------
4062 when Attribute_Has_Discriminants =>
4063 Legal_Formal_Attribute;
4065 --------------
4066 -- Identity --
4067 --------------
4069 when Attribute_Identity =>
4070 Check_E0;
4071 Analyze (P);
4073 if Etype (P) = Standard_Exception_Type then
4074 Set_Etype (N, RTE (RE_Exception_Id));
4076 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to task
4077 -- interface class-wide types.
4079 elsif Is_Task_Type (Etype (P))
4080 or else (Is_Access_Type (Etype (P))
4081 and then Is_Task_Type (Designated_Type (Etype (P))))
4082 or else (Ada_Version >= Ada_2005
4083 and then Ekind (Etype (P)) = E_Class_Wide_Type
4084 and then Is_Interface (Etype (P))
4085 and then Is_Task_Interface (Etype (P)))
4086 then
4087 Resolve (P);
4088 Set_Etype (N, RTE (RO_AT_Task_Id));
4090 else
4091 if Ada_Version >= Ada_2005 then
4092 Error_Attr_P
4093 ("prefix of % attribute must be an exception, a task or a "
4094 & "task interface class-wide object");
4095 else
4096 Error_Attr_P
4097 ("prefix of % attribute must be a task or an exception");
4098 end if;
4099 end if;
4101 -----------
4102 -- Image --
4103 -----------
4105 when Attribute_Image =>
4106 if Is_Real_Type (P_Type) then
4107 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
4108 Error_Msg_Name_1 := Aname;
4109 Error_Msg_N
4110 ("(Ada 83) % attribute not allowed for real types", N);
4111 end if;
4112 end if;
4114 Analyze_Image_Attribute (Standard_String);
4116 ---------
4117 -- Img --
4118 ---------
4120 when Attribute_Img =>
4121 Analyze_Image_Attribute (Standard_String);
4123 -----------
4124 -- Input --
4125 -----------
4127 when Attribute_Input =>
4128 Check_E1;
4129 Check_Stream_Attribute (TSS_Stream_Input);
4130 Set_Etype (N, P_Base_Type);
4132 -------------------
4133 -- Integer_Value --
4134 -------------------
4136 when Attribute_Integer_Value =>
4137 Check_E1;
4138 Check_Integer_Type;
4139 Resolve (E1, Any_Fixed);
4141 -- Signal an error if argument type is not a specific fixed-point
4142 -- subtype. An error has been signalled already if the argument
4143 -- was not of a fixed-point type.
4145 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
4146 Error_Attr ("argument of % must be of a fixed-point type", E1);
4147 end if;
4149 Set_Etype (N, P_Base_Type);
4151 -------------------
4152 -- Invalid_Value --
4153 -------------------
4155 when Attribute_Invalid_Value =>
4156 Check_E0;
4157 Check_Scalar_Type;
4158 Set_Etype (N, P_Base_Type);
4159 Invalid_Value_Used := True;
4161 -----------
4162 -- Large --
4163 -----------
4165 when Attribute_Large =>
4166 Check_E0;
4167 Check_Real_Type;
4168 Set_Etype (N, Universal_Real);
4170 ----------
4171 -- Last --
4172 ----------
4174 when Attribute_Last =>
4175 Check_Array_Or_Scalar_Type;
4176 Bad_Attribute_For_Predicate;
4178 --------------
4179 -- Last_Bit --
4180 --------------
4182 when Attribute_Last_Bit =>
4183 Check_Component;
4184 Set_Etype (N, Universal_Integer);
4186 ----------------
4187 -- Last_Valid --
4188 ----------------
4190 when Attribute_Last_Valid =>
4191 Check_First_Last_Valid;
4192 Set_Etype (N, P_Type);
4194 ------------------
4195 -- Leading_Part --
4196 ------------------
4198 when Attribute_Leading_Part =>
4199 Check_Floating_Point_Type_2;
4200 Set_Etype (N, P_Base_Type);
4201 Resolve (E1, P_Base_Type);
4202 Resolve (E2, Any_Integer);
4204 ------------
4205 -- Length --
4206 ------------
4208 when Attribute_Length =>
4209 Check_Array_Type;
4210 Set_Etype (N, Universal_Integer);
4212 -------------------
4213 -- Library_Level --
4214 -------------------
4216 when Attribute_Library_Level =>
4217 Check_E0;
4219 if not Is_Entity_Name (P) then
4220 Error_Attr_P ("prefix of % attribute must be an entity name");
4221 end if;
4223 if not Inside_A_Generic then
4224 Set_Boolean_Result (N,
4225 Is_Library_Level_Entity (Entity (P)));
4226 end if;
4228 Set_Etype (N, Standard_Boolean);
4230 ---------------
4231 -- Lock_Free --
4232 ---------------
4234 when Attribute_Lock_Free =>
4235 Check_E0;
4236 Set_Etype (N, Standard_Boolean);
4238 if not Is_Protected_Type (P_Type) then
4239 Error_Attr_P
4240 ("prefix of % attribute must be a protected object");
4241 end if;
4243 ----------------
4244 -- Loop_Entry --
4245 ----------------
4247 when Attribute_Loop_Entry => Loop_Entry : declare
4248 procedure Check_References_In_Prefix (Loop_Id : Entity_Id);
4249 -- Inspect the prefix for any uses of entities declared within the
4250 -- related loop. Loop_Id denotes the loop identifier.
4252 --------------------------------
4253 -- Check_References_In_Prefix --
4254 --------------------------------
4256 procedure Check_References_In_Prefix (Loop_Id : Entity_Id) is
4257 Loop_Decl : constant Node_Id := Label_Construct (Parent (Loop_Id));
4259 function Check_Reference (Nod : Node_Id) return Traverse_Result;
4260 -- Determine whether a reference mentions an entity declared
4261 -- within the related loop.
4263 function Declared_Within (Nod : Node_Id) return Boolean;
4264 -- Determine whether Nod appears in the subtree of Loop_Decl
4266 ---------------------
4267 -- Check_Reference --
4268 ---------------------
4270 function Check_Reference (Nod : Node_Id) return Traverse_Result is
4271 begin
4272 if Nkind (Nod) = N_Identifier
4273 and then Present (Entity (Nod))
4274 and then Declared_Within (Declaration_Node (Entity (Nod)))
4275 then
4276 Error_Attr
4277 ("prefix of attribute % cannot reference local entities",
4278 Nod);
4279 return Abandon;
4280 else
4281 return OK;
4282 end if;
4283 end Check_Reference;
4285 procedure Check_References is new Traverse_Proc (Check_Reference);
4287 ---------------------
4288 -- Declared_Within --
4289 ---------------------
4291 function Declared_Within (Nod : Node_Id) return Boolean is
4292 Stmt : Node_Id;
4294 begin
4295 Stmt := Nod;
4296 while Present (Stmt) loop
4297 if Stmt = Loop_Decl then
4298 return True;
4300 -- Prevent the search from going too far
4302 elsif Is_Body_Or_Package_Declaration (Stmt) then
4303 exit;
4304 end if;
4306 Stmt := Parent (Stmt);
4307 end loop;
4309 return False;
4310 end Declared_Within;
4312 -- Start of processing for Check_Prefix_For_Local_References
4314 begin
4315 Check_References (P);
4316 end Check_References_In_Prefix;
4318 -- Local variables
4320 Context : constant Node_Id := Parent (N);
4321 Attr : Node_Id;
4322 Encl_Loop : Node_Id := Empty;
4323 Encl_Prag : Node_Id := Empty;
4324 Loop_Id : Entity_Id := Empty;
4325 Scop : Entity_Id;
4326 Stmt : Node_Id;
4328 -- Start of processing for Loop_Entry
4330 begin
4331 Attr := N;
4333 -- Set the type of the attribute now to ensure the successful
4334 -- continuation of analysis even if the attribute is misplaced.
4336 Set_Etype (Attr, P_Type);
4338 -- Attribute 'Loop_Entry may appear in several flavors:
4340 -- * Prefix'Loop_Entry - in this form, the attribute applies to the
4341 -- nearest enclosing loop.
4343 -- * Prefix'Loop_Entry (Expr) - depending on what Expr denotes, the
4344 -- attribute may be related to a loop denoted by label Expr or
4345 -- the prefix may denote an array object and Expr may act as an
4346 -- indexed component.
4348 -- * Prefix'Loop_Entry (Expr1, ..., ExprN) - the attribute applies
4349 -- to the nearest enclosing loop, all expressions are part of
4350 -- an indexed component.
4352 -- * Prefix'Loop_Entry (Expr) (...) (...) - depending on what Expr
4353 -- denotes, the attribute may be related to a loop denoted by
4354 -- label Expr or the prefix may denote a multidimensional array
4355 -- array object and Expr along with the rest of the expressions
4356 -- may act as indexed components.
4358 -- Regardless of variations, the attribute reference does not have an
4359 -- expression list. Instead, all available expressions are stored as
4360 -- indexed components.
4362 -- When the attribute is part of an indexed component, find the first
4363 -- expression as it will determine the semantics of 'Loop_Entry.
4365 -- If the attribute is itself an index in an indexed component, i.e.
4366 -- a member of a list, the context itself is not relevant (the code
4367 -- below would lead to an infinite loop) and the attribute applies
4368 -- to the enclosing loop.
4370 if Nkind (Context) = N_Indexed_Component
4371 and then not Is_List_Member (N)
4372 then
4373 E1 := First (Expressions (Context));
4374 E2 := Next (E1);
4376 -- The attribute reference appears in the following form:
4378 -- Prefix'Loop_Entry (Exp1, Expr2, ..., ExprN) [(...)]
4380 -- In this case, the loop name is omitted and no rewriting is
4381 -- required.
4383 if Present (E2) then
4384 null;
4386 -- The form of the attribute is:
4388 -- Prefix'Loop_Entry (Expr) [(...)]
4390 -- If Expr denotes a loop entry, the whole attribute and indexed
4391 -- component will have to be rewritten to reflect this relation.
4393 else
4394 pragma Assert (Present (E1));
4396 -- Do not expand the expression as it may have side effects.
4397 -- Simply preanalyze to determine whether it is a loop name or
4398 -- something else.
4400 Preanalyze_And_Resolve (E1);
4402 if Is_Entity_Name (E1)
4403 and then Present (Entity (E1))
4404 and then Ekind (Entity (E1)) = E_Loop
4405 then
4406 Loop_Id := Entity (E1);
4408 -- Transform the attribute and enclosing indexed component
4410 Set_Expressions (N, Expressions (Context));
4411 Rewrite (Context, N);
4412 Set_Etype (Context, P_Type);
4414 Attr := Context;
4415 end if;
4416 end if;
4417 end if;
4419 -- The prefix must denote an object
4421 if not Is_Object_Reference (P) then
4422 Error_Attr_P ("prefix of attribute % must denote an object");
4423 end if;
4425 -- The prefix cannot be of a limited type because the expansion of
4426 -- Loop_Entry must create a constant initialized by the evaluated
4427 -- prefix.
4429 if Is_Limited_View (Etype (P)) then
4430 Error_Attr_P ("prefix of attribute % cannot be limited");
4431 end if;
4433 -- Climb the parent chain to verify the location of the attribute and
4434 -- find the enclosing loop.
4436 Stmt := Attr;
4437 while Present (Stmt) loop
4439 -- Locate the corresponding enclosing pragma. Note that in the
4440 -- case of Assert[And_Cut] and Assume, we have already checked
4441 -- that the pragma appears in an appropriate loop location.
4443 if Nkind (Original_Node (Stmt)) = N_Pragma
4444 and then Nam_In (Pragma_Name_Unmapped (Original_Node (Stmt)),
4445 Name_Loop_Invariant,
4446 Name_Loop_Variant,
4447 Name_Assert,
4448 Name_Assert_And_Cut,
4449 Name_Assume)
4450 then
4451 Encl_Prag := Original_Node (Stmt);
4453 -- Locate the enclosing loop (if any). Note that Ada 2012 array
4454 -- iteration may be expanded into several nested loops, we are
4455 -- interested in the outermost one which has the loop identifier,
4456 -- and comes from source.
4458 elsif Nkind (Stmt) = N_Loop_Statement
4459 and then Present (Identifier (Stmt))
4460 and then Comes_From_Source (Original_Node (Stmt))
4461 and then Nkind (Original_Node (Stmt)) = N_Loop_Statement
4462 then
4463 Encl_Loop := Stmt;
4465 -- The original attribute reference may lack a loop name. Use
4466 -- the name of the enclosing loop because it is the related
4467 -- loop.
4469 if No (Loop_Id) then
4470 Loop_Id := Entity (Identifier (Encl_Loop));
4471 end if;
4473 exit;
4475 -- Prevent the search from going too far
4477 elsif Is_Body_Or_Package_Declaration (Stmt) then
4478 exit;
4479 end if;
4481 Stmt := Parent (Stmt);
4482 end loop;
4484 -- Loop_Entry must appear within a Loop_Assertion pragma (Assert,
4485 -- Assert_And_Cut, Assume count as loop assertion pragmas for this
4486 -- purpose if they appear in an appropriate location in a loop,
4487 -- which was already checked by the top level pragma circuit).
4489 -- Loop_Entry also denotes a value and as such can appear within an
4490 -- expression that is an argument for another loop aspect. In that
4491 -- case it will have been expanded into the corresponding assignment.
4493 if Expander_Active
4494 and then Nkind (Parent (N)) = N_Assignment_Statement
4495 and then not Comes_From_Source (Parent (N))
4496 then
4497 null;
4499 elsif No (Encl_Prag) then
4500 Error_Attr ("attribute% must appear within appropriate pragma", N);
4501 end if;
4503 -- A Loop_Entry that applies to a given loop statement must not
4504 -- appear within a body of accept statement, if this construct is
4505 -- itself enclosed by the given loop statement.
4507 for Index in reverse 0 .. Scope_Stack.Last loop
4508 Scop := Scope_Stack.Table (Index).Entity;
4510 if Ekind (Scop) = E_Loop and then Scop = Loop_Id then
4511 exit;
4512 elsif Ekind_In (Scop, E_Block, E_Loop, E_Return_Statement) then
4513 null;
4514 else
4515 Error_Attr
4516 ("attribute % cannot appear in body or accept statement", N);
4517 exit;
4518 end if;
4519 end loop;
4521 -- The prefix cannot mention entities declared within the related
4522 -- loop because they will not be visible once the prefix is moved
4523 -- outside the loop.
4525 Check_References_In_Prefix (Loop_Id);
4527 -- The prefix must denote a static entity if the pragma does not
4528 -- apply to the innermost enclosing loop statement, or if it appears
4529 -- within a potentially unevaluated epxression.
4531 if Is_Entity_Name (P)
4532 or else Nkind (Parent (P)) = N_Object_Renaming_Declaration
4533 or else Statically_Denotes_Object (P)
4534 then
4535 null;
4537 elsif Present (Encl_Loop)
4538 and then Entity (Identifier (Encl_Loop)) /= Loop_Id
4539 then
4540 Error_Attr_P
4541 ("prefix of attribute % that applies to outer loop must denote "
4542 & "an entity");
4544 elsif Is_Potentially_Unevaluated (P) then
4545 Uneval_Old_Msg;
4546 end if;
4548 -- Replace the Loop_Entry attribute reference by its prefix if the
4549 -- related pragma is ignored. This transformation is OK with respect
4550 -- to typing because Loop_Entry's type is that of its prefix. This
4551 -- early transformation also avoids the generation of a useless loop
4552 -- entry constant.
4554 if Present (Encl_Prag) and then Is_Ignored (Encl_Prag) then
4555 Rewrite (N, Relocate_Node (P));
4556 Preanalyze_And_Resolve (N);
4558 else
4559 Preanalyze_And_Resolve (P);
4560 end if;
4561 end Loop_Entry;
4563 -------------
4564 -- Machine --
4565 -------------
4567 when Attribute_Machine =>
4568 Check_Floating_Point_Type_1;
4569 Set_Etype (N, P_Base_Type);
4570 Resolve (E1, P_Base_Type);
4572 ------------------
4573 -- Machine_Emax --
4574 ------------------
4576 when Attribute_Machine_Emax =>
4577 Check_Floating_Point_Type_0;
4578 Set_Etype (N, Universal_Integer);
4580 ------------------
4581 -- Machine_Emin --
4582 ------------------
4584 when Attribute_Machine_Emin =>
4585 Check_Floating_Point_Type_0;
4586 Set_Etype (N, Universal_Integer);
4588 ----------------------
4589 -- Machine_Mantissa --
4590 ----------------------
4592 when Attribute_Machine_Mantissa =>
4593 Check_Floating_Point_Type_0;
4594 Set_Etype (N, Universal_Integer);
4596 -----------------------
4597 -- Machine_Overflows --
4598 -----------------------
4600 when Attribute_Machine_Overflows =>
4601 Check_Real_Type;
4602 Check_E0;
4603 Set_Etype (N, Standard_Boolean);
4605 -------------------
4606 -- Machine_Radix --
4607 -------------------
4609 when Attribute_Machine_Radix =>
4610 Check_Real_Type;
4611 Check_E0;
4612 Set_Etype (N, Universal_Integer);
4614 ----------------------
4615 -- Machine_Rounding --
4616 ----------------------
4618 when Attribute_Machine_Rounding =>
4619 Check_Floating_Point_Type_1;
4620 Set_Etype (N, P_Base_Type);
4621 Resolve (E1, P_Base_Type);
4623 --------------------
4624 -- Machine_Rounds --
4625 --------------------
4627 when Attribute_Machine_Rounds =>
4628 Check_Real_Type;
4629 Check_E0;
4630 Set_Etype (N, Standard_Boolean);
4632 ------------------
4633 -- Machine_Size --
4634 ------------------
4636 when Attribute_Machine_Size =>
4637 Check_E0;
4638 Check_Type;
4639 Check_Not_Incomplete_Type;
4640 Set_Etype (N, Universal_Integer);
4642 --------------
4643 -- Mantissa --
4644 --------------
4646 when Attribute_Mantissa =>
4647 Check_E0;
4648 Check_Real_Type;
4649 Set_Etype (N, Universal_Integer);
4651 ---------
4652 -- Max --
4653 ---------
4655 when Attribute_Max =>
4656 Min_Max;
4658 ----------------------------------
4659 -- Max_Alignment_For_Allocation --
4660 ----------------------------------
4662 when Attribute_Max_Size_In_Storage_Elements =>
4663 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4665 ----------------------------------
4666 -- Max_Size_In_Storage_Elements --
4667 ----------------------------------
4669 when Attribute_Max_Alignment_For_Allocation =>
4670 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4672 -----------------------
4673 -- Maximum_Alignment --
4674 -----------------------
4676 when Attribute_Maximum_Alignment =>
4677 Standard_Attribute (Ttypes.Maximum_Alignment);
4679 --------------------
4680 -- Mechanism_Code --
4681 --------------------
4683 when Attribute_Mechanism_Code =>
4684 if not Is_Entity_Name (P)
4685 or else not Is_Subprogram (Entity (P))
4686 then
4687 Error_Attr_P ("prefix of % attribute must be subprogram");
4688 end if;
4690 Check_Either_E0_Or_E1;
4692 if Present (E1) then
4693 Resolve (E1, Any_Integer);
4694 Set_Etype (E1, Standard_Integer);
4696 if not Is_OK_Static_Expression (E1) then
4697 Flag_Non_Static_Expr
4698 ("expression for parameter number must be static!", E1);
4699 Error_Attr;
4701 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
4702 or else UI_To_Int (Intval (E1)) < 0
4703 then
4704 Error_Attr ("invalid parameter number for % attribute", E1);
4705 end if;
4706 end if;
4708 Set_Etype (N, Universal_Integer);
4710 ---------
4711 -- Min --
4712 ---------
4714 when Attribute_Min =>
4715 Min_Max;
4717 ---------
4718 -- Mod --
4719 ---------
4721 when Attribute_Mod =>
4723 -- Note: this attribute is only allowed in Ada 2005 mode, but
4724 -- we do not need to test that here, since Mod is only recognized
4725 -- as an attribute name in Ada 2005 mode during the parse.
4727 Check_E1;
4728 Check_Modular_Integer_Type;
4729 Resolve (E1, Any_Integer);
4730 Set_Etype (N, P_Base_Type);
4732 -----------
4733 -- Model --
4734 -----------
4736 when Attribute_Model =>
4737 Check_Floating_Point_Type_1;
4738 Set_Etype (N, P_Base_Type);
4739 Resolve (E1, P_Base_Type);
4741 ----------------
4742 -- Model_Emin --
4743 ----------------
4745 when Attribute_Model_Emin =>
4746 Check_Floating_Point_Type_0;
4747 Set_Etype (N, Universal_Integer);
4749 -------------------
4750 -- Model_Epsilon --
4751 -------------------
4753 when Attribute_Model_Epsilon =>
4754 Check_Floating_Point_Type_0;
4755 Set_Etype (N, Universal_Real);
4757 --------------------
4758 -- Model_Mantissa --
4759 --------------------
4761 when Attribute_Model_Mantissa =>
4762 Check_Floating_Point_Type_0;
4763 Set_Etype (N, Universal_Integer);
4765 -----------------
4766 -- Model_Small --
4767 -----------------
4769 when Attribute_Model_Small =>
4770 Check_Floating_Point_Type_0;
4771 Set_Etype (N, Universal_Real);
4773 -------------
4774 -- Modulus --
4775 -------------
4777 when Attribute_Modulus =>
4778 Check_E0;
4779 Check_Modular_Integer_Type;
4780 Set_Etype (N, Universal_Integer);
4782 --------------------
4783 -- Null_Parameter --
4784 --------------------
4786 when Attribute_Null_Parameter => Null_Parameter : declare
4787 Parnt : constant Node_Id := Parent (N);
4788 GParnt : constant Node_Id := Parent (Parnt);
4790 procedure Bad_Null_Parameter (Msg : String);
4791 -- Used if bad Null parameter attribute node is found. Issues
4792 -- given error message, and also sets the type to Any_Type to
4793 -- avoid blowups later on from dealing with a junk node.
4795 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
4796 -- Called to check that Proc_Ent is imported subprogram
4798 ------------------------
4799 -- Bad_Null_Parameter --
4800 ------------------------
4802 procedure Bad_Null_Parameter (Msg : String) is
4803 begin
4804 Error_Msg_N (Msg, N);
4805 Set_Etype (N, Any_Type);
4806 end Bad_Null_Parameter;
4808 ----------------------
4809 -- Must_Be_Imported --
4810 ----------------------
4812 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
4813 Pent : constant Entity_Id := Ultimate_Alias (Proc_Ent);
4815 begin
4816 -- Ignore check if procedure not frozen yet (we will get
4817 -- another chance when the default parameter is reanalyzed)
4819 if not Is_Frozen (Pent) then
4820 return;
4822 elsif not Is_Imported (Pent) then
4823 Bad_Null_Parameter
4824 ("Null_Parameter can only be used with imported subprogram");
4826 else
4827 return;
4828 end if;
4829 end Must_Be_Imported;
4831 -- Start of processing for Null_Parameter
4833 begin
4834 Check_Type;
4835 Check_E0;
4836 Set_Etype (N, P_Type);
4838 -- Case of attribute used as default expression
4840 if Nkind (Parnt) = N_Parameter_Specification then
4841 Must_Be_Imported (Defining_Entity (GParnt));
4843 -- Case of attribute used as actual for subprogram (positional)
4845 elsif Nkind (Parnt) in N_Subprogram_Call
4846 and then Is_Entity_Name (Name (Parnt))
4847 then
4848 Must_Be_Imported (Entity (Name (Parnt)));
4850 -- Case of attribute used as actual for subprogram (named)
4852 elsif Nkind (Parnt) = N_Parameter_Association
4853 and then Nkind (GParnt) in N_Subprogram_Call
4854 and then Is_Entity_Name (Name (GParnt))
4855 then
4856 Must_Be_Imported (Entity (Name (GParnt)));
4858 -- Not an allowed case
4860 else
4861 Bad_Null_Parameter
4862 ("Null_Parameter must be actual or default parameter");
4863 end if;
4864 end Null_Parameter;
4866 -----------------
4867 -- Object_Size --
4868 -----------------
4870 when Attribute_Object_Size =>
4871 Check_E0;
4872 Check_Type;
4873 Check_Not_Incomplete_Type;
4874 Set_Etype (N, Universal_Integer);
4876 ---------
4877 -- Old --
4878 ---------
4880 when Attribute_Old => Old : declare
4881 procedure Check_References_In_Prefix (Subp_Id : Entity_Id);
4882 -- Inspect the contents of the prefix and detect illegal uses of a
4883 -- nested 'Old, attribute 'Result or a use of an entity declared in
4884 -- the related postcondition expression. Subp_Id is the subprogram to
4885 -- which the related postcondition applies.
4887 --------------------------------
4888 -- Check_References_In_Prefix --
4889 --------------------------------
4891 procedure Check_References_In_Prefix (Subp_Id : Entity_Id) is
4892 function Check_Reference (Nod : Node_Id) return Traverse_Result;
4893 -- Detect attribute 'Old, attribute 'Result of a use of an entity
4894 -- and perform the appropriate semantic check.
4896 ---------------------
4897 -- Check_Reference --
4898 ---------------------
4900 function Check_Reference (Nod : Node_Id) return Traverse_Result is
4901 begin
4902 -- Attributes 'Old and 'Result cannot appear in the prefix of
4903 -- another attribute 'Old.
4905 if Nkind (Nod) = N_Attribute_Reference
4906 and then Nam_In (Attribute_Name (Nod), Name_Old,
4907 Name_Result)
4908 then
4909 Error_Msg_Name_1 := Attribute_Name (Nod);
4910 Error_Msg_Name_2 := Name_Old;
4911 Error_Msg_N
4912 ("attribute % cannot appear in the prefix of attribute %",
4913 Nod);
4914 return Abandon;
4916 -- Entities mentioned within the prefix of attribute 'Old must
4917 -- be global to the related postcondition. If this is not the
4918 -- case, then the scope of the local entity is nested within
4919 -- that of the subprogram.
4921 elsif Is_Entity_Name (Nod)
4922 and then Present (Entity (Nod))
4923 and then Scope_Within (Scope (Entity (Nod)), Subp_Id)
4924 then
4925 Error_Attr
4926 ("prefix of attribute % cannot reference local entities",
4927 Nod);
4928 return Abandon;
4930 -- Otherwise keep inspecting the prefix
4932 else
4933 return OK;
4934 end if;
4935 end Check_Reference;
4937 procedure Check_References is new Traverse_Proc (Check_Reference);
4939 -- Start of processing for Check_References_In_Prefix
4941 begin
4942 Check_References (P);
4943 end Check_References_In_Prefix;
4945 -- Local variables
4947 Legal : Boolean;
4948 Pref_Id : Entity_Id;
4949 Pref_Typ : Entity_Id;
4950 Spec_Id : Entity_Id;
4952 -- Start of processing for Old
4954 begin
4955 -- The attribute reference is a primary. If any expressions follow,
4956 -- then the attribute reference is an indexable object. Transform the
4957 -- attribute into an indexed component and analyze it.
4959 if Present (E1) then
4960 Rewrite (N,
4961 Make_Indexed_Component (Loc,
4962 Prefix =>
4963 Make_Attribute_Reference (Loc,
4964 Prefix => Relocate_Node (P),
4965 Attribute_Name => Name_Old),
4966 Expressions => Expressions (N)));
4967 Analyze (N);
4968 return;
4969 end if;
4971 Analyze_Attribute_Old_Result (Legal, Spec_Id);
4973 -- The aspect or pragma where attribute 'Old resides should be
4974 -- associated with a subprogram declaration or a body. If this is not
4975 -- the case, then the aspect or pragma is illegal. Return as analysis
4976 -- cannot be carried out.
4978 -- The exception to this rule is when generating C since in this case
4979 -- postconditions are inlined.
4981 if No (Spec_Id)
4982 and then Modify_Tree_For_C
4983 and then In_Inlined_Body
4984 then
4985 Spec_Id := Entity (P);
4987 elsif not Legal then
4988 return;
4989 end if;
4991 -- The prefix must be preanalyzed as the full analysis will take
4992 -- place during expansion.
4994 Preanalyze_And_Resolve (P);
4996 -- Ensure that the prefix does not contain attributes 'Old or 'Result
4998 Check_References_In_Prefix (Spec_Id);
5000 -- Set the type of the attribute now to prevent cascaded errors
5002 Pref_Typ := Etype (P);
5003 Set_Etype (N, Pref_Typ);
5005 -- Legality checks
5007 if Is_Limited_Type (Pref_Typ) then
5008 Error_Attr ("attribute % cannot apply to limited objects", P);
5009 end if;
5011 -- The prefix is a simple name
5013 if Is_Entity_Name (P) and then Present (Entity (P)) then
5014 Pref_Id := Entity (P);
5016 -- Emit a warning when the prefix is a constant. Note that the use
5017 -- of Error_Attr would reset the type of N to Any_Type even though
5018 -- this is a warning. Use Error_Msg_XXX instead.
5020 if Is_Constant_Object (Pref_Id) then
5021 Error_Msg_Name_1 := Name_Old;
5022 Error_Msg_N
5023 ("??attribute % applied to constant has no effect", P);
5024 end if;
5026 -- Otherwise the prefix is not a simple name
5028 else
5029 -- Ensure that the prefix of attribute 'Old is an entity when it
5030 -- is potentially unevaluated (6.1.1 (27/3)).
5032 if Is_Potentially_Unevaluated (N)
5033 and then not Statically_Denotes_Object (P)
5034 then
5035 Uneval_Old_Msg;
5037 -- Detect a possible infinite recursion when the prefix denotes
5038 -- the related function.
5040 -- function Func (...) return ...
5041 -- with Post => Func'Old ...;
5043 -- The function may be specified in qualified form X.Y where X is
5044 -- a protected object and Y is a protected function. In that case
5045 -- ensure that the qualified form has an entity.
5047 elsif Nkind (P) = N_Function_Call
5048 and then Nkind (Name (P)) in N_Has_Entity
5049 then
5050 Pref_Id := Entity (Name (P));
5052 if Ekind_In (Spec_Id, E_Function, E_Generic_Function)
5053 and then Pref_Id = Spec_Id
5054 then
5055 Error_Msg_Warn := SPARK_Mode /= On;
5056 Error_Msg_N ("!possible infinite recursion<<", P);
5057 Error_Msg_N ("\!??Storage_Error ]<<", P);
5058 end if;
5059 end if;
5061 -- The prefix of attribute 'Old may refer to a component of a
5062 -- formal parameter. In this case its expansion may generate
5063 -- actual subtypes that are referenced in an inner context and
5064 -- that must be elaborated within the subprogram itself. If the
5065 -- prefix includes a function call, it may involve finalization
5066 -- actions that should be inserted when the attribute has been
5067 -- rewritten as a declaration. Create a declaration for the prefix
5068 -- and insert it at the start of the enclosing subprogram. This is
5069 -- an expansion activity that has to be performed now to prevent
5070 -- out-of-order issues.
5072 -- This expansion is both harmful and not needed in SPARK mode,
5073 -- since the formal verification back end relies on the types of
5074 -- nodes (hence is not robust w.r.t. a change to base type here),
5075 -- and does not suffer from the out-of-order issue described
5076 -- above. Thus, this expansion is skipped in SPARK mode.
5078 -- The expansion is not relevant for discrete types, which will
5079 -- not generate extra declarations, and where use of the base type
5080 -- may lead to spurious errors if context is a case.
5082 if not GNATprove_Mode then
5083 if not Is_Discrete_Type (Pref_Typ) then
5084 Pref_Typ := Base_Type (Pref_Typ);
5085 end if;
5087 Set_Etype (N, Pref_Typ);
5088 Set_Etype (P, Pref_Typ);
5090 Analyze_Dimension (N);
5091 Expand (N);
5092 end if;
5093 end if;
5094 end Old;
5096 ----------------------
5097 -- Overlaps_Storage --
5098 ----------------------
5100 when Attribute_Overlaps_Storage =>
5101 Check_E1;
5103 -- Both arguments must be objects of any type
5105 Analyze_And_Resolve (P);
5106 Analyze_And_Resolve (E1);
5107 Check_Object_Reference (P);
5108 Check_Object_Reference (E1);
5109 Set_Etype (N, Standard_Boolean);
5111 ------------
5112 -- Output --
5113 ------------
5115 when Attribute_Output =>
5116 Check_E2;
5117 Check_Stream_Attribute (TSS_Stream_Output);
5118 Set_Etype (N, Standard_Void_Type);
5119 Resolve (N, Standard_Void_Type);
5121 ------------------
5122 -- Partition_ID --
5123 ------------------
5125 when Attribute_Partition_ID =>
5126 Check_E0;
5128 if P_Type /= Any_Type then
5129 if not Is_Library_Level_Entity (Entity (P)) then
5130 Error_Attr_P
5131 ("prefix of % attribute must be library-level entity");
5133 -- The defining entity of prefix should not be declared inside a
5134 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
5136 elsif Is_Entity_Name (P)
5137 and then Is_Pure (Entity (P))
5138 then
5139 Error_Attr_P ("prefix of% attribute must not be declared pure");
5140 end if;
5141 end if;
5143 Set_Etype (N, Universal_Integer);
5145 -------------------------
5146 -- Passed_By_Reference --
5147 -------------------------
5149 when Attribute_Passed_By_Reference =>
5150 Check_E0;
5151 Check_Type;
5152 Set_Etype (N, Standard_Boolean);
5154 ------------------
5155 -- Pool_Address --
5156 ------------------
5158 when Attribute_Pool_Address =>
5159 Check_E0;
5160 Set_Etype (N, RTE (RE_Address));
5162 ---------
5163 -- Pos --
5164 ---------
5166 when Attribute_Pos =>
5167 Check_Discrete_Type;
5168 Check_E1;
5170 if Is_Boolean_Type (P_Type) then
5171 Error_Msg_Name_1 := Aname;
5172 Error_Msg_Name_2 := Chars (P_Type);
5173 Check_SPARK_05_Restriction
5174 ("attribute% is not allowed for type%", P);
5175 end if;
5177 Resolve (E1, P_Base_Type);
5178 Set_Etype (N, Universal_Integer);
5180 --------------
5181 -- Position --
5182 --------------
5184 when Attribute_Position =>
5185 Check_Component;
5186 Set_Etype (N, Universal_Integer);
5188 ----------
5189 -- Pred --
5190 ----------
5192 when Attribute_Pred =>
5193 Check_Scalar_Type;
5194 Check_E1;
5196 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
5197 Error_Msg_Name_1 := Aname;
5198 Error_Msg_Name_2 := Chars (P_Type);
5199 Check_SPARK_05_Restriction
5200 ("attribute% is not allowed for type%", P);
5201 end if;
5203 Resolve (E1, P_Base_Type);
5204 Set_Etype (N, P_Base_Type);
5206 -- Since Pred works on the base type, we normally do no check for the
5207 -- floating-point case, since the base type is unconstrained. But we
5208 -- make an exception in Check_Float_Overflow mode.
5210 if Is_Floating_Point_Type (P_Type) then
5211 if not Range_Checks_Suppressed (P_Base_Type) then
5212 Set_Do_Range_Check (E1);
5213 end if;
5215 -- If not modular type, test for overflow check required
5217 else
5218 if not Is_Modular_Integer_Type (P_Type)
5219 and then not Range_Checks_Suppressed (P_Base_Type)
5220 then
5221 Enable_Range_Check (E1);
5222 end if;
5223 end if;
5225 --------------
5226 -- Priority --
5227 --------------
5229 -- Ada 2005 (AI-327): Dynamic ceiling priorities
5231 when Attribute_Priority =>
5232 if Ada_Version < Ada_2005 then
5233 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
5234 end if;
5236 Check_E0;
5238 Check_Restriction (No_Dynamic_Priorities, N);
5240 -- The prefix must be a protected object (AARM D.5.2 (2/2))
5242 Analyze (P);
5244 if Is_Protected_Type (Etype (P))
5245 or else (Is_Access_Type (Etype (P))
5246 and then Is_Protected_Type (Designated_Type (Etype (P))))
5247 then
5248 Resolve (P, Etype (P));
5249 else
5250 Error_Attr_P ("prefix of % attribute must be a protected object");
5251 end if;
5253 Set_Etype (N, Standard_Integer);
5255 -- Must be called from within a protected procedure or entry of the
5256 -- protected object.
5258 declare
5259 S : Entity_Id;
5261 begin
5262 S := Current_Scope;
5263 while S /= Etype (P)
5264 and then S /= Standard_Standard
5265 loop
5266 S := Scope (S);
5267 end loop;
5269 if S = Standard_Standard then
5270 Error_Attr ("the attribute % is only allowed inside protected "
5271 & "operations", P);
5272 end if;
5273 end;
5275 Validate_Non_Static_Attribute_Function_Call;
5277 -----------
5278 -- Range --
5279 -----------
5281 when Attribute_Range =>
5282 Check_Array_Or_Scalar_Type;
5283 Bad_Attribute_For_Predicate;
5285 if Ada_Version = Ada_83
5286 and then Is_Scalar_Type (P_Type)
5287 and then Comes_From_Source (N)
5288 then
5289 Error_Attr
5290 ("(Ada 83) % attribute not allowed for scalar type", P);
5291 end if;
5293 ------------
5294 -- Result --
5295 ------------
5297 when Attribute_Result => Result : declare
5298 function Denote_Same_Function
5299 (Pref_Id : Entity_Id;
5300 Spec_Id : Entity_Id) return Boolean;
5301 -- Determine whether the entity of the prefix Pref_Id denotes the
5302 -- same entity as that of the related subprogram Spec_Id.
5304 --------------------------
5305 -- Denote_Same_Function --
5306 --------------------------
5308 function Denote_Same_Function
5309 (Pref_Id : Entity_Id;
5310 Spec_Id : Entity_Id) return Boolean
5312 Over_Id : constant Entity_Id := Overridden_Operation (Spec_Id);
5313 Subp_Spec : constant Node_Id := Parent (Spec_Id);
5315 begin
5316 -- The prefix denotes the related subprogram
5318 if Pref_Id = Spec_Id then
5319 return True;
5321 -- Account for a special case when attribute 'Result appears in
5322 -- the postcondition of a generic function.
5324 -- generic
5325 -- function Gen_Func return ...
5326 -- with Post => Gen_Func'Result ...;
5328 -- When the generic function is instantiated, the Chars field of
5329 -- the instantiated prefix still denotes the name of the generic
5330 -- function. Note that any preemptive transformation is impossible
5331 -- without a proper analysis. The structure of the wrapper package
5332 -- is as follows:
5334 -- package Anon_Gen_Pack is
5335 -- <subtypes and renamings>
5336 -- function Subp_Decl return ...; -- (!)
5337 -- pragma Postcondition (Gen_Func'Result ...); -- (!)
5338 -- function Gen_Func ... renames Subp_Decl;
5339 -- end Anon_Gen_Pack;
5341 elsif Nkind (Subp_Spec) = N_Function_Specification
5342 and then Present (Generic_Parent (Subp_Spec))
5343 and then Ekind_In (Pref_Id, E_Generic_Function, E_Function)
5344 then
5345 if Generic_Parent (Subp_Spec) = Pref_Id then
5346 return True;
5348 elsif Present (Alias (Pref_Id))
5349 and then Alias (Pref_Id) = Spec_Id
5350 then
5351 return True;
5352 end if;
5354 -- Account for a special case where a primitive of a tagged type
5355 -- inherits a class-wide postcondition from a parent type. In this
5356 -- case the prefix of attribute 'Result denotes the overriding
5357 -- primitive.
5359 elsif Present (Over_Id) and then Pref_Id = Over_Id then
5360 return True;
5361 end if;
5363 -- Otherwise the prefix does not denote the related subprogram
5365 return False;
5366 end Denote_Same_Function;
5368 -- Local variables
5370 In_Inlined_C_Postcondition : constant Boolean :=
5371 Modify_Tree_For_C
5372 and then In_Inlined_Body;
5374 Legal : Boolean;
5375 Pref_Id : Entity_Id;
5376 Spec_Id : Entity_Id;
5378 -- Start of processing for Result
5380 begin
5381 -- The attribute reference is a primary. If any expressions follow,
5382 -- then the attribute reference is an indexable object. Transform the
5383 -- attribute into an indexed component and analyze it.
5385 if Present (E1) then
5386 Rewrite (N,
5387 Make_Indexed_Component (Loc,
5388 Prefix =>
5389 Make_Attribute_Reference (Loc,
5390 Prefix => Relocate_Node (P),
5391 Attribute_Name => Name_Result),
5392 Expressions => Expressions (N)));
5393 Analyze (N);
5394 return;
5395 end if;
5397 Analyze_Attribute_Old_Result (Legal, Spec_Id);
5399 -- The aspect or pragma where attribute 'Result resides should be
5400 -- associated with a subprogram declaration or a body. If this is not
5401 -- the case, then the aspect or pragma is illegal. Return as analysis
5402 -- cannot be carried out.
5404 -- The exception to this rule is when generating C since in this case
5405 -- postconditions are inlined.
5407 if No (Spec_Id) and then In_Inlined_C_Postcondition then
5408 Spec_Id := Entity (P);
5410 elsif not Legal then
5411 return;
5412 end if;
5414 -- Attribute 'Result is part of a _Postconditions procedure. There is
5415 -- no need to perform the semantic checks below as they were already
5416 -- verified when the attribute was analyzed in its original context.
5417 -- Instead, rewrite the attribute as a reference to formal parameter
5418 -- _Result of the _Postconditions procedure.
5420 if Chars (Spec_Id) = Name_uPostconditions
5421 or else
5422 (In_Inlined_C_Postcondition
5423 and then Nkind (Parent (Spec_Id)) = N_Block_Statement)
5424 then
5425 Rewrite (N, Make_Identifier (Loc, Name_uResult));
5427 -- The type of formal parameter _Result is that of the function
5428 -- encapsulating the _Postconditions procedure. Resolution must
5429 -- be carried out against the function return type.
5431 Analyze_And_Resolve (N, Etype (Scope (Spec_Id)));
5433 -- Otherwise attribute 'Result appears in its original context and
5434 -- all semantic checks should be carried out.
5436 else
5437 -- Verify the legality of the prefix. It must denotes the entity
5438 -- of the related [generic] function.
5440 if Is_Entity_Name (P) then
5441 Pref_Id := Entity (P);
5443 if Ekind_In (Pref_Id, E_Function, E_Generic_Function)
5444 and then Ekind (Spec_Id) = Ekind (Pref_Id)
5445 then
5446 if Denote_Same_Function (Pref_Id, Spec_Id) then
5448 -- Correct the prefix of the attribute when the context
5449 -- is a generic function.
5451 if Pref_Id /= Spec_Id then
5452 Rewrite (P, New_Occurrence_Of (Spec_Id, Loc));
5453 Analyze (P);
5454 end if;
5456 Set_Etype (N, Etype (Spec_Id));
5458 -- Otherwise the prefix denotes some unrelated function
5460 else
5461 Error_Msg_Name_2 := Chars (Spec_Id);
5462 Error_Attr
5463 ("incorrect prefix for attribute %, expected %", P);
5464 end if;
5466 -- Otherwise the prefix denotes some other form of subprogram
5467 -- entity.
5469 else
5470 Error_Attr
5471 ("attribute % can only appear in postcondition of "
5472 & "function", P);
5473 end if;
5475 -- Otherwise the prefix is illegal
5477 else
5478 Error_Msg_Name_2 := Chars (Spec_Id);
5479 Error_Attr ("incorrect prefix for attribute %, expected %", P);
5480 end if;
5481 end if;
5482 end Result;
5484 ------------------
5485 -- Range_Length --
5486 ------------------
5488 when Attribute_Range_Length =>
5489 Check_E0;
5490 Check_Discrete_Type;
5491 Set_Etype (N, Universal_Integer);
5493 ----------
5494 -- Read --
5495 ----------
5497 when Attribute_Read =>
5498 Check_E2;
5499 Check_Stream_Attribute (TSS_Stream_Read);
5500 Set_Etype (N, Standard_Void_Type);
5501 Resolve (N, Standard_Void_Type);
5502 Note_Possible_Modification (E2, Sure => True);
5504 ---------
5505 -- Ref --
5506 ---------
5508 when Attribute_Ref =>
5509 Check_E1;
5510 Analyze (P);
5512 if Nkind (P) /= N_Expanded_Name
5513 or else not Is_RTE (P_Type, RE_Address)
5514 then
5515 Error_Attr_P ("prefix of % attribute must be System.Address");
5516 end if;
5518 Analyze_And_Resolve (E1, Any_Integer);
5519 Set_Etype (N, RTE (RE_Address));
5521 ---------------
5522 -- Remainder --
5523 ---------------
5525 when Attribute_Remainder =>
5526 Check_Floating_Point_Type_2;
5527 Set_Etype (N, P_Base_Type);
5528 Resolve (E1, P_Base_Type);
5529 Resolve (E2, P_Base_Type);
5531 ---------------------
5532 -- Restriction_Set --
5533 ---------------------
5535 when Attribute_Restriction_Set => Restriction_Set : declare
5536 R : Restriction_Id;
5537 U : Node_Id;
5538 Unam : Unit_Name_Type;
5540 begin
5541 Check_E1;
5542 Analyze (P);
5543 Check_System_Prefix;
5545 -- No_Dependence case
5547 if Nkind (E1) = N_Parameter_Association then
5548 pragma Assert (Chars (Selector_Name (E1)) = Name_No_Dependence);
5549 U := Explicit_Actual_Parameter (E1);
5551 if not OK_No_Dependence_Unit_Name (U) then
5552 Set_Boolean_Result (N, False);
5553 Error_Attr;
5554 end if;
5556 -- See if there is an entry already in the table. That's the
5557 -- case in which we can return True.
5559 for J in No_Dependences.First .. No_Dependences.Last loop
5560 if Designate_Same_Unit (U, No_Dependences.Table (J).Unit)
5561 and then No_Dependences.Table (J).Warn = False
5562 then
5563 Set_Boolean_Result (N, True);
5564 return;
5565 end if;
5566 end loop;
5568 -- If not in the No_Dependence table, result is False
5570 Set_Boolean_Result (N, False);
5572 -- In this case, we must ensure that the binder will reject any
5573 -- other unit in the partition that sets No_Dependence for this
5574 -- unit. We do that by making an entry in the special table kept
5575 -- for this purpose (if the entry is not there already).
5577 Unam := Get_Spec_Name (Get_Unit_Name (U));
5579 for J in Restriction_Set_Dependences.First ..
5580 Restriction_Set_Dependences.Last
5581 loop
5582 if Restriction_Set_Dependences.Table (J) = Unam then
5583 return;
5584 end if;
5585 end loop;
5587 Restriction_Set_Dependences.Append (Unam);
5589 -- Normal restriction case
5591 else
5592 if Nkind (E1) /= N_Identifier then
5593 Set_Boolean_Result (N, False);
5594 Error_Attr ("attribute % requires restriction identifier", E1);
5596 else
5597 R := Get_Restriction_Id (Process_Restriction_Synonyms (E1));
5599 if R = Not_A_Restriction_Id then
5600 Set_Boolean_Result (N, False);
5601 Error_Msg_Node_1 := E1;
5602 Error_Attr ("invalid restriction identifier &", E1);
5604 elsif R not in Partition_Boolean_Restrictions then
5605 Set_Boolean_Result (N, False);
5606 Error_Msg_Node_1 := E1;
5607 Error_Attr
5608 ("& is not a boolean partition-wide restriction", E1);
5609 end if;
5611 if Restriction_Active (R) then
5612 Set_Boolean_Result (N, True);
5613 else
5614 Check_Restriction (R, N);
5615 Set_Boolean_Result (N, False);
5616 end if;
5617 end if;
5618 end if;
5619 end Restriction_Set;
5621 -----------
5622 -- Round --
5623 -----------
5625 when Attribute_Round =>
5626 Check_E1;
5627 Check_Decimal_Fixed_Point_Type;
5628 Set_Etype (N, P_Base_Type);
5630 -- Because the context is universal_real (3.5.10(12)) it is a
5631 -- legal context for a universal fixed expression. This is the
5632 -- only attribute whose functional description involves U_R.
5634 if Etype (E1) = Universal_Fixed then
5635 declare
5636 Conv : constant Node_Id := Make_Type_Conversion (Loc,
5637 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
5638 Expression => Relocate_Node (E1));
5640 begin
5641 Rewrite (E1, Conv);
5642 Analyze (E1);
5643 end;
5644 end if;
5646 Resolve (E1, Any_Real);
5648 --------------
5649 -- Rounding --
5650 --------------
5652 when Attribute_Rounding =>
5653 Check_Floating_Point_Type_1;
5654 Set_Etype (N, P_Base_Type);
5655 Resolve (E1, P_Base_Type);
5657 ---------------
5658 -- Safe_Emax --
5659 ---------------
5661 when Attribute_Safe_Emax =>
5662 Check_Floating_Point_Type_0;
5663 Set_Etype (N, Universal_Integer);
5665 ----------------
5666 -- Safe_First --
5667 ----------------
5669 when Attribute_Safe_First =>
5670 Check_Floating_Point_Type_0;
5671 Set_Etype (N, Universal_Real);
5673 ----------------
5674 -- Safe_Large --
5675 ----------------
5677 when Attribute_Safe_Large =>
5678 Check_E0;
5679 Check_Real_Type;
5680 Set_Etype (N, Universal_Real);
5682 ---------------
5683 -- Safe_Last --
5684 ---------------
5686 when Attribute_Safe_Last =>
5687 Check_Floating_Point_Type_0;
5688 Set_Etype (N, Universal_Real);
5690 ----------------
5691 -- Safe_Small --
5692 ----------------
5694 when Attribute_Safe_Small =>
5695 Check_E0;
5696 Check_Real_Type;
5697 Set_Etype (N, Universal_Real);
5699 --------------------------
5700 -- Scalar_Storage_Order --
5701 --------------------------
5703 when Attribute_Scalar_Storage_Order => Scalar_Storage_Order : declare
5704 Ent : Entity_Id := Empty;
5706 begin
5707 Check_E0;
5708 Check_Type;
5710 if not (Is_Record_Type (P_Type) or else Is_Array_Type (P_Type)) then
5712 -- In GNAT mode, the attribute applies to generic types as well
5713 -- as composite types, and for non-composite types always returns
5714 -- the default bit order for the target.
5716 if not (GNAT_Mode and then Is_Generic_Type (P_Type))
5717 and then not In_Instance
5718 then
5719 Error_Attr_P
5720 ("prefix of % attribute must be record or array type");
5722 elsif not Is_Generic_Type (P_Type) then
5723 if Bytes_Big_Endian then
5724 Ent := RTE (RE_High_Order_First);
5725 else
5726 Ent := RTE (RE_Low_Order_First);
5727 end if;
5728 end if;
5730 elsif Bytes_Big_Endian xor Reverse_Storage_Order (P_Type) then
5731 Ent := RTE (RE_High_Order_First);
5733 else
5734 Ent := RTE (RE_Low_Order_First);
5735 end if;
5737 if Present (Ent) then
5738 Rewrite (N, New_Occurrence_Of (Ent, Loc));
5739 end if;
5741 Set_Etype (N, RTE (RE_Bit_Order));
5742 Resolve (N);
5744 -- Reset incorrect indication of staticness
5746 Set_Is_Static_Expression (N, False);
5747 end Scalar_Storage_Order;
5749 -----------
5750 -- Scale --
5751 -----------
5753 when Attribute_Scale =>
5754 Check_E0;
5755 Check_Decimal_Fixed_Point_Type;
5756 Set_Etype (N, Universal_Integer);
5758 -------------
5759 -- Scaling --
5760 -------------
5762 when Attribute_Scaling =>
5763 Check_Floating_Point_Type_2;
5764 Set_Etype (N, P_Base_Type);
5765 Resolve (E1, P_Base_Type);
5767 ------------------
5768 -- Signed_Zeros --
5769 ------------------
5771 when Attribute_Signed_Zeros =>
5772 Check_Floating_Point_Type_0;
5773 Set_Etype (N, Standard_Boolean);
5775 ----------
5776 -- Size --
5777 ----------
5779 when Attribute_Size
5780 | Attribute_VADS_Size
5782 Check_E0;
5784 -- If prefix is parameterless function call, rewrite and resolve
5785 -- as such.
5787 if Is_Entity_Name (P)
5788 and then Ekind (Entity (P)) = E_Function
5789 then
5790 Resolve (P);
5792 -- Similar processing for a protected function call
5794 elsif Nkind (P) = N_Selected_Component
5795 and then Ekind (Entity (Selector_Name (P))) = E_Function
5796 then
5797 Resolve (P);
5798 end if;
5800 if Is_Object_Reference (P) then
5801 Check_Object_Reference (P);
5803 elsif Is_Entity_Name (P)
5804 and then (Is_Type (Entity (P))
5805 or else Ekind (Entity (P)) = E_Enumeration_Literal)
5806 then
5807 null;
5809 elsif Nkind (P) = N_Type_Conversion
5810 and then not Comes_From_Source (P)
5811 then
5812 null;
5814 -- Some other compilers allow dubious use of X'???'Size
5816 elsif Relaxed_RM_Semantics
5817 and then Nkind (P) = N_Attribute_Reference
5818 then
5819 null;
5821 else
5822 Error_Attr_P ("invalid prefix for % attribute");
5823 end if;
5825 Check_Not_Incomplete_Type;
5826 Check_Not_CPP_Type;
5827 Set_Etype (N, Universal_Integer);
5829 -- If we are processing pragmas Compile_Time_Warning and Compile_
5830 -- Time_Errors after the back end has been called and this occurrence
5831 -- of 'Size is known at compile time then it is safe to perform this
5832 -- evaluation. Needed to perform the static evaluation of the full
5833 -- boolean expression of these pragmas.
5835 if In_Compile_Time_Warning_Or_Error
5836 and then Is_Entity_Name (P)
5837 and then (Is_Type (Entity (P))
5838 or else Ekind (Entity (P)) = E_Enumeration_Literal)
5839 and then Size_Known_At_Compile_Time (Entity (P))
5840 then
5841 Rewrite (N, Make_Integer_Literal (Sloc (N), Esize (Entity (P))));
5842 Analyze (N);
5843 end if;
5845 -----------
5846 -- Small --
5847 -----------
5849 when Attribute_Small =>
5850 Check_E0;
5851 Check_Real_Type;
5852 Set_Etype (N, Universal_Real);
5854 ------------------
5855 -- Storage_Pool --
5856 ------------------
5858 when Attribute_Storage_Pool
5859 | Attribute_Simple_Storage_Pool
5861 Check_E0;
5863 if Is_Access_Type (P_Type) then
5864 if Ekind (P_Type) = E_Access_Subprogram_Type then
5865 Error_Attr_P
5866 ("cannot use % attribute for access-to-subprogram type");
5867 end if;
5869 -- Set appropriate entity
5871 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
5872 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
5873 else
5874 Set_Entity (N, RTE (RE_Global_Pool_Object));
5875 end if;
5877 if Attr_Id = Attribute_Storage_Pool then
5878 if Present (Get_Rep_Pragma (Etype (Entity (N)),
5879 Name_Simple_Storage_Pool_Type))
5880 then
5881 Error_Msg_Name_1 := Aname;
5882 Error_Msg_Warn := SPARK_Mode /= On;
5883 Error_Msg_N
5884 ("cannot use % attribute for type with simple storage "
5885 & "pool<<", N);
5886 Error_Msg_N ("\Program_Error [<<", N);
5888 Rewrite
5889 (N, Make_Raise_Program_Error
5890 (Sloc (N), Reason => PE_Explicit_Raise));
5891 end if;
5893 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
5895 -- In the Simple_Storage_Pool case, verify that the pool entity is
5896 -- actually of a simple storage pool type, and set the attribute's
5897 -- type to the pool object's type.
5899 else
5900 if not Present (Get_Rep_Pragma (Etype (Entity (N)),
5901 Name_Simple_Storage_Pool_Type))
5902 then
5903 Error_Attr_P
5904 ("cannot use % attribute for type without simple " &
5905 "storage pool");
5906 end if;
5908 Set_Etype (N, Etype (Entity (N)));
5909 end if;
5911 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5912 -- Storage_Pool since this attribute is not defined for such
5913 -- types (RM E.2.3(22)).
5915 Validate_Remote_Access_To_Class_Wide_Type (N);
5917 else
5918 Error_Attr_P ("prefix of % attribute must be access type");
5919 end if;
5921 ------------------
5922 -- Storage_Size --
5923 ------------------
5925 when Attribute_Storage_Size =>
5926 Check_E0;
5928 if Is_Task_Type (P_Type) then
5929 Set_Etype (N, Universal_Integer);
5931 -- Use with tasks is an obsolescent feature
5933 Check_Restriction (No_Obsolescent_Features, P);
5935 elsif Is_Access_Type (P_Type) then
5936 if Ekind (P_Type) = E_Access_Subprogram_Type then
5937 Error_Attr_P
5938 ("cannot use % attribute for access-to-subprogram type");
5939 end if;
5941 if Is_Entity_Name (P)
5942 and then Is_Type (Entity (P))
5943 then
5944 Check_Type;
5945 Set_Etype (N, Universal_Integer);
5947 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5948 -- Storage_Size since this attribute is not defined for
5949 -- such types (RM E.2.3(22)).
5951 Validate_Remote_Access_To_Class_Wide_Type (N);
5953 -- The prefix is allowed to be an implicit dereference of an
5954 -- access value designating a task.
5956 else
5957 Check_Task_Prefix;
5958 Set_Etype (N, Universal_Integer);
5959 end if;
5961 else
5962 Error_Attr_P ("prefix of % attribute must be access or task type");
5963 end if;
5965 ------------------
5966 -- Storage_Unit --
5967 ------------------
5969 when Attribute_Storage_Unit =>
5970 Standard_Attribute (Ttypes.System_Storage_Unit);
5972 -----------------
5973 -- Stream_Size --
5974 -----------------
5976 when Attribute_Stream_Size =>
5977 Check_E0;
5978 Check_Type;
5980 if Is_Entity_Name (P)
5981 and then Is_Elementary_Type (Entity (P))
5982 then
5983 Set_Etype (N, Universal_Integer);
5984 else
5985 Error_Attr_P ("invalid prefix for % attribute");
5986 end if;
5988 ---------------
5989 -- Stub_Type --
5990 ---------------
5992 when Attribute_Stub_Type =>
5993 Check_Type;
5994 Check_E0;
5996 if Is_Remote_Access_To_Class_Wide_Type (Base_Type (P_Type)) then
5998 -- For a real RACW [sub]type, use corresponding stub type
6000 if not Is_Generic_Type (P_Type) then
6001 Rewrite (N,
6002 New_Occurrence_Of
6003 (Corresponding_Stub_Type (Base_Type (P_Type)), Loc));
6005 -- For a generic type (that has been marked as an RACW using the
6006 -- Remote_Access_Type aspect or pragma), use a generic RACW stub
6007 -- type. Note that if the actual is not a remote access type, the
6008 -- instantiation will fail.
6010 else
6011 -- Note: we go to the underlying type here because the view
6012 -- returned by RTE (RE_RACW_Stub_Type) might be incomplete.
6014 Rewrite (N,
6015 New_Occurrence_Of
6016 (Underlying_Type (RTE (RE_RACW_Stub_Type)), Loc));
6017 end if;
6019 else
6020 Error_Attr_P
6021 ("prefix of% attribute must be remote access-to-class-wide");
6022 end if;
6024 ----------
6025 -- Succ --
6026 ----------
6028 when Attribute_Succ =>
6029 Check_Scalar_Type;
6030 Check_E1;
6032 if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
6033 Error_Msg_Name_1 := Aname;
6034 Error_Msg_Name_2 := Chars (P_Type);
6035 Check_SPARK_05_Restriction
6036 ("attribute% is not allowed for type%", P);
6037 end if;
6039 Resolve (E1, P_Base_Type);
6040 Set_Etype (N, P_Base_Type);
6042 -- Since Pred works on the base type, we normally do no check for the
6043 -- floating-point case, since the base type is unconstrained. But we
6044 -- make an exception in Check_Float_Overflow mode.
6046 if Is_Floating_Point_Type (P_Type) then
6047 if not Range_Checks_Suppressed (P_Base_Type) then
6048 Set_Do_Range_Check (E1);
6049 end if;
6051 -- If not modular type, test for overflow check required
6053 else
6054 if not Is_Modular_Integer_Type (P_Type)
6055 and then not Range_Checks_Suppressed (P_Base_Type)
6056 then
6057 Enable_Range_Check (E1);
6058 end if;
6059 end if;
6061 --------------------------------
6062 -- System_Allocator_Alignment --
6063 --------------------------------
6065 when Attribute_System_Allocator_Alignment =>
6066 Standard_Attribute (Ttypes.System_Allocator_Alignment);
6068 ---------
6069 -- Tag --
6070 ---------
6072 when Attribute_Tag =>
6073 Check_E0;
6074 Check_Dereference;
6076 if not Is_Tagged_Type (P_Type) then
6077 Error_Attr_P ("prefix of % attribute must be tagged");
6079 -- Next test does not apply to generated code why not, and what does
6080 -- the illegal reference mean???
6082 elsif Is_Object_Reference (P)
6083 and then not Is_Class_Wide_Type (P_Type)
6084 and then Comes_From_Source (N)
6085 then
6086 Error_Attr_P
6087 ("% attribute can only be applied to objects " &
6088 "of class - wide type");
6089 end if;
6091 -- The prefix cannot be an incomplete type. However, references to
6092 -- 'Tag can be generated when expanding interface conversions, and
6093 -- this is legal.
6095 if Comes_From_Source (N) then
6096 Check_Not_Incomplete_Type;
6097 end if;
6099 -- Set appropriate type
6101 Set_Etype (N, RTE (RE_Tag));
6103 -----------------
6104 -- Target_Name --
6105 -----------------
6107 when Attribute_Target_Name => Target_Name : declare
6108 TN : constant String := Sdefault.Target_Name.all;
6109 TL : Natural;
6111 begin
6112 Check_Standard_Prefix;
6114 TL := TN'Last;
6116 if TN (TL) = '/' or else TN (TL) = '\' then
6117 TL := TL - 1;
6118 end if;
6120 Rewrite (N,
6121 Make_String_Literal (Loc,
6122 Strval => TN (TN'First .. TL)));
6123 Analyze_And_Resolve (N, Standard_String);
6124 Set_Is_Static_Expression (N, True);
6125 end Target_Name;
6127 ----------------
6128 -- Terminated --
6129 ----------------
6131 when Attribute_Terminated =>
6132 Check_E0;
6133 Set_Etype (N, Standard_Boolean);
6134 Check_Task_Prefix;
6136 ----------------
6137 -- To_Address --
6138 ----------------
6140 when Attribute_To_Address => To_Address : declare
6141 Val : Uint;
6143 begin
6144 Check_E1;
6145 Analyze (P);
6146 Check_System_Prefix;
6148 Generate_Reference (RTE (RE_Address), P);
6149 Analyze_And_Resolve (E1, Any_Integer);
6150 Set_Etype (N, RTE (RE_Address));
6152 if Is_Static_Expression (E1) then
6153 Set_Is_Static_Expression (N, True);
6154 end if;
6156 -- OK static expression case, check range and set appropriate type
6158 if Is_OK_Static_Expression (E1) then
6159 Val := Expr_Value (E1);
6161 if Val < -(2 ** UI_From_Int (Standard'Address_Size - 1))
6162 or else
6163 Val > 2 ** UI_From_Int (Standard'Address_Size) - 1
6164 then
6165 Error_Attr ("address value out of range for % attribute", E1);
6166 end if;
6168 -- In most cases the expression is a numeric literal or some other
6169 -- address expression, but if it is a declared constant it may be
6170 -- of a compatible type that must be left on the node.
6172 if Is_Entity_Name (E1) then
6173 null;
6175 -- Set type to universal integer if negative
6177 elsif Val < 0 then
6178 Set_Etype (E1, Universal_Integer);
6180 -- Otherwise set type to Unsigned_64 to accommodate max values
6182 else
6183 Set_Etype (E1, Standard_Unsigned_64);
6184 end if;
6185 end if;
6187 Set_Is_Static_Expression (N, True);
6188 end To_Address;
6190 ------------
6191 -- To_Any --
6192 ------------
6194 when Attribute_To_Any =>
6195 Check_E1;
6196 Check_PolyORB_Attribute;
6197 Set_Etype (N, RTE (RE_Any));
6199 ----------------
6200 -- Truncation --
6201 ----------------
6203 when Attribute_Truncation =>
6204 Check_Floating_Point_Type_1;
6205 Resolve (E1, P_Base_Type);
6206 Set_Etype (N, P_Base_Type);
6208 ----------------
6209 -- Type_Class --
6210 ----------------
6212 when Attribute_Type_Class =>
6213 Check_E0;
6214 Check_Type;
6215 Check_Not_Incomplete_Type;
6216 Set_Etype (N, RTE (RE_Type_Class));
6218 --------------
6219 -- TypeCode --
6220 --------------
6222 when Attribute_TypeCode =>
6223 Check_E0;
6224 Check_PolyORB_Attribute;
6225 Set_Etype (N, RTE (RE_TypeCode));
6227 --------------
6228 -- Type_Key --
6229 --------------
6231 when Attribute_Type_Key => Type_Key : declare
6232 Full_Name : constant String_Id :=
6233 Fully_Qualified_Name_String (Entity (P));
6235 CRC : CRC32;
6236 -- The computed signature for the type
6238 Deref : Boolean;
6239 -- To simplify the handling of mutually recursive types, follow a
6240 -- single dereference link in a composite type.
6242 procedure Compute_Type_Key (T : Entity_Id);
6243 -- Create a CRC integer from the declaration of the type. For a
6244 -- composite type, fold in the representation of its components in
6245 -- recursive fashion. We use directly the source representation of
6246 -- the types involved.
6248 ----------------------
6249 -- Compute_Type_Key --
6250 ----------------------
6252 procedure Compute_Type_Key (T : Entity_Id) is
6253 Buffer : Source_Buffer_Ptr;
6254 P_Max : Source_Ptr;
6255 P_Min : Source_Ptr;
6256 Rep : Node_Id;
6257 SFI : Source_File_Index;
6259 procedure Process_One_Declaration;
6260 -- Update CRC with the characters of one type declaration, or a
6261 -- representation pragma that applies to the type.
6263 -----------------------------
6264 -- Process_One_Declaration --
6265 -----------------------------
6267 procedure Process_One_Declaration is
6268 begin
6269 -- Scan type declaration, skipping blanks
6271 for Ptr in P_Min .. P_Max loop
6272 if Buffer (Ptr) /= ' ' then
6273 System.CRC32.Update (CRC, Buffer (Ptr));
6274 end if;
6275 end loop;
6276 end Process_One_Declaration;
6278 -- Start of processing for Compute_Type_Key
6280 begin
6281 if Is_Itype (T) then
6282 return;
6283 end if;
6285 -- If the type is declared in Standard, there is no source, so
6286 -- just use its name.
6288 if Scope (T) = Standard_Standard then
6289 declare
6290 Name : constant String := Get_Name_String (Chars (T));
6291 begin
6292 for J in Name'Range loop
6293 System.CRC32.Update (CRC, Name (J));
6294 end loop;
6295 end;
6297 return;
6298 end if;
6300 Sloc_Range (Enclosing_Declaration (T), P_Min, P_Max);
6301 SFI := Get_Source_File_Index (P_Min);
6302 pragma Assert (SFI = Get_Source_File_Index (P_Max));
6303 Buffer := Source_Text (SFI);
6305 Process_One_Declaration;
6307 -- Recurse on relevant component types
6309 if Is_Array_Type (T) then
6310 Compute_Type_Key (Component_Type (T));
6312 elsif Is_Access_Type (T) then
6313 if not Deref then
6314 Deref := True;
6315 Compute_Type_Key (Designated_Type (T));
6316 end if;
6318 elsif Is_Derived_Type (T) then
6319 Compute_Type_Key (Etype (T));
6321 elsif Is_Record_Type (T) then
6322 declare
6323 Comp : Entity_Id;
6324 begin
6325 Comp := First_Component (T);
6326 while Present (Comp) loop
6327 Compute_Type_Key (Etype (Comp));
6328 Next_Component (Comp);
6329 end loop;
6330 end;
6331 end if;
6333 if Is_First_Subtype (T) then
6335 -- Fold in representation aspects for the type, which appear in
6336 -- the same source buffer. If the representation aspects are in
6337 -- a different source file, then skip them; they apply to some
6338 -- other type, perhaps one we're derived from.
6340 Rep := First_Rep_Item (T);
6342 while Present (Rep) loop
6343 if Comes_From_Source (Rep) then
6344 Sloc_Range (Rep, P_Min, P_Max);
6346 if SFI = Get_Source_File_Index (P_Min) then
6347 pragma Assert (SFI = Get_Source_File_Index (P_Max));
6348 Process_One_Declaration;
6349 end if;
6350 end if;
6352 Rep := Next_Rep_Item (Rep);
6353 end loop;
6354 end if;
6355 end Compute_Type_Key;
6357 -- Start of processing for Type_Key
6359 begin
6360 Check_E0;
6361 Check_Type;
6363 Start_String;
6364 Deref := False;
6366 -- Copy all characters in Full_Name but the trailing NUL
6368 for J in 1 .. String_Length (Full_Name) - 1 loop
6369 Store_String_Char (Get_String_Char (Full_Name, Pos (J)));
6370 end loop;
6372 -- Compute CRC and convert it to string one character at a time, so
6373 -- as not to use Image within the compiler.
6375 Initialize (CRC);
6376 Compute_Type_Key (Entity (P));
6378 if not Is_Frozen (Entity (P)) then
6379 Error_Msg_N ("premature usage of Type_Key?", N);
6380 end if;
6382 while CRC > 0 loop
6383 Store_String_Char (Character'Val (48 + (CRC rem 10)));
6384 CRC := CRC / 10;
6385 end loop;
6387 Rewrite (N, Make_String_Literal (Loc, End_String));
6388 Analyze_And_Resolve (N, Standard_String);
6389 end Type_Key;
6391 -----------------------
6392 -- Unbiased_Rounding --
6393 -----------------------
6395 when Attribute_Unbiased_Rounding =>
6396 Check_Floating_Point_Type_1;
6397 Set_Etype (N, P_Base_Type);
6398 Resolve (E1, P_Base_Type);
6400 ----------------------
6401 -- Unchecked_Access --
6402 ----------------------
6404 when Attribute_Unchecked_Access =>
6405 if Comes_From_Source (N) then
6406 Check_Restriction (No_Unchecked_Access, N);
6407 end if;
6409 Analyze_Access_Attribute;
6410 Check_Not_Incomplete_Type;
6412 -------------------------
6413 -- Unconstrained_Array --
6414 -------------------------
6416 when Attribute_Unconstrained_Array =>
6417 Check_E0;
6418 Check_Type;
6419 Check_Not_Incomplete_Type;
6420 Set_Etype (N, Standard_Boolean);
6421 Set_Is_Static_Expression (N, True);
6423 ------------------------------
6424 -- Universal_Literal_String --
6425 ------------------------------
6427 -- This is a GNAT specific attribute whose prefix must be a named
6428 -- number where the expression is either a single numeric literal,
6429 -- or a numeric literal immediately preceded by a minus sign. The
6430 -- result is equivalent to a string literal containing the text of
6431 -- the literal as it appeared in the source program with a possible
6432 -- leading minus sign.
6434 when Attribute_Universal_Literal_String =>
6435 Check_E0;
6437 if not Is_Entity_Name (P)
6438 or else Ekind (Entity (P)) not in Named_Kind
6439 then
6440 Error_Attr_P ("prefix for % attribute must be named number");
6442 else
6443 declare
6444 Expr : Node_Id;
6445 Negative : Boolean;
6446 S : Source_Ptr;
6447 Src : Source_Buffer_Ptr;
6449 begin
6450 Expr := Original_Node (Expression (Parent (Entity (P))));
6452 if Nkind (Expr) = N_Op_Minus then
6453 Negative := True;
6454 Expr := Original_Node (Right_Opnd (Expr));
6455 else
6456 Negative := False;
6457 end if;
6459 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
6460 Error_Attr
6461 ("named number for % attribute must be simple literal", N);
6462 end if;
6464 -- Build string literal corresponding to source literal text
6466 Start_String;
6468 if Negative then
6469 Store_String_Char (Get_Char_Code ('-'));
6470 end if;
6472 S := Sloc (Expr);
6473 Src := Source_Text (Get_Source_File_Index (S));
6475 while Src (S) /= ';' and then Src (S) /= ' ' loop
6476 Store_String_Char (Get_Char_Code (Src (S)));
6477 S := S + 1;
6478 end loop;
6480 -- Now we rewrite the attribute with the string literal
6482 Rewrite (N,
6483 Make_String_Literal (Loc, End_String));
6484 Analyze (N);
6485 Set_Is_Static_Expression (N, True);
6486 end;
6487 end if;
6489 -------------------------
6490 -- Unrestricted_Access --
6491 -------------------------
6493 -- This is a GNAT specific attribute which is like Access except that
6494 -- all scope checks and checks for aliased views are omitted. It is
6495 -- documented as being equivalent to the use of the Address attribute
6496 -- followed by an unchecked conversion to the target access type.
6498 when Attribute_Unrestricted_Access =>
6500 -- If from source, deal with relevant restrictions
6502 if Comes_From_Source (N) then
6503 Check_Restriction (No_Unchecked_Access, N);
6505 if Nkind (P) in N_Has_Entity
6506 and then Present (Entity (P))
6507 and then Is_Object (Entity (P))
6508 then
6509 Check_Restriction (No_Implicit_Aliasing, N);
6510 end if;
6511 end if;
6513 if Is_Entity_Name (P) then
6514 Set_Address_Taken (Entity (P));
6515 end if;
6517 -- It might seem reasonable to call Address_Checks here to apply the
6518 -- same set of semantic checks that we enforce for 'Address (after
6519 -- all we document Unrestricted_Access as being equivalent to the
6520 -- use of Address followed by an Unchecked_Conversion). However, if
6521 -- we do enable these checks, we get multiple failures in both the
6522 -- compiler run-time and in our regression test suite, so we leave
6523 -- out these checks for now. To be investigated further some time???
6525 -- Address_Checks;
6527 -- Now complete analysis using common access processing
6529 Analyze_Access_Attribute;
6531 ------------
6532 -- Update --
6533 ------------
6535 when Attribute_Update => Update : declare
6536 Common_Typ : Entity_Id;
6537 -- The common type of a multiple component update for a record
6539 Comps : Elist_Id := No_Elist;
6540 -- A list used in the resolution of a record update. It contains the
6541 -- entities of all record components processed so far.
6543 procedure Analyze_Array_Component_Update (Assoc : Node_Id);
6544 -- Analyze and resolve array_component_association Assoc against the
6545 -- index of array type P_Type.
6547 procedure Analyze_Record_Component_Update (Comp : Node_Id);
6548 -- Analyze and resolve record_component_association Comp against
6549 -- record type P_Type.
6551 ------------------------------------
6552 -- Analyze_Array_Component_Update --
6553 ------------------------------------
6555 procedure Analyze_Array_Component_Update (Assoc : Node_Id) is
6556 Expr : Node_Id;
6557 High : Node_Id;
6558 Index : Node_Id;
6559 Index_Typ : Entity_Id;
6560 Low : Node_Id;
6562 begin
6563 -- The current association contains a sequence of indexes denoting
6564 -- an element of a multidimensional array:
6566 -- (Index_1, ..., Index_N)
6568 -- Examine each individual index and resolve it against the proper
6569 -- index type of the array.
6571 if Nkind (First (Choices (Assoc))) = N_Aggregate then
6572 Expr := First (Choices (Assoc));
6573 while Present (Expr) loop
6575 -- The use of others is illegal (SPARK RM 4.4.1(12))
6577 if Nkind (Expr) = N_Others_Choice then
6578 Error_Attr
6579 ("others choice not allowed in attribute %", Expr);
6581 -- Otherwise analyze and resolve all indexes
6583 else
6584 Index := First (Expressions (Expr));
6585 Index_Typ := First_Index (P_Type);
6586 while Present (Index) and then Present (Index_Typ) loop
6587 Analyze_And_Resolve (Index, Etype (Index_Typ));
6588 Next (Index);
6589 Next_Index (Index_Typ);
6590 end loop;
6592 -- Detect a case where the association either lacks an
6593 -- index or contains an extra index.
6595 if Present (Index) or else Present (Index_Typ) then
6596 Error_Msg_N
6597 ("dimension mismatch in index list", Assoc);
6598 end if;
6599 end if;
6601 Next (Expr);
6602 end loop;
6604 -- The current association denotes either a single component or a
6605 -- range of components of a one dimensional array:
6607 -- 1, 2 .. 5
6609 -- Resolve the index or its high and low bounds (if range) against
6610 -- the proper index type of the array.
6612 else
6613 Index := First (Choices (Assoc));
6614 Index_Typ := First_Index (P_Type);
6616 if Present (Next_Index (Index_Typ)) then
6617 Error_Msg_N ("too few subscripts in array reference", Assoc);
6618 end if;
6620 while Present (Index) loop
6622 -- The use of others is illegal (SPARK RM 4.4.1(12))
6624 if Nkind (Index) = N_Others_Choice then
6625 Error_Attr
6626 ("others choice not allowed in attribute %", Index);
6628 -- The index denotes a range of elements
6630 elsif Nkind (Index) = N_Range then
6631 Low := Low_Bound (Index);
6632 High := High_Bound (Index);
6634 Analyze_And_Resolve (Low, Etype (Index_Typ));
6635 Analyze_And_Resolve (High, Etype (Index_Typ));
6637 -- Add a range check to ensure that the bounds of the
6638 -- range are within the index type when this cannot be
6639 -- determined statically.
6641 if not Is_OK_Static_Expression (Low) then
6642 Set_Do_Range_Check (Low);
6643 end if;
6645 if not Is_OK_Static_Expression (High) then
6646 Set_Do_Range_Check (High);
6647 end if;
6649 -- Otherwise the index denotes a single element
6651 else
6652 Analyze_And_Resolve (Index, Etype (Index_Typ));
6654 -- Add a range check to ensure that the index is within
6655 -- the index type when it is not possible to determine
6656 -- this statically.
6658 if not Is_OK_Static_Expression (Index) then
6659 Set_Do_Range_Check (Index);
6660 end if;
6661 end if;
6663 Next (Index);
6664 end loop;
6665 end if;
6666 end Analyze_Array_Component_Update;
6668 -------------------------------------
6669 -- Analyze_Record_Component_Update --
6670 -------------------------------------
6672 procedure Analyze_Record_Component_Update (Comp : Node_Id) is
6673 Comp_Name : constant Name_Id := Chars (Comp);
6674 Base_Typ : Entity_Id;
6675 Comp_Or_Discr : Entity_Id;
6677 begin
6678 -- Find the discriminant or component whose name corresponds to
6679 -- Comp. A simple character comparison is sufficient because all
6680 -- visible names within a record type are unique.
6682 Comp_Or_Discr := First_Entity (P_Type);
6683 while Present (Comp_Or_Discr) loop
6684 if Chars (Comp_Or_Discr) = Comp_Name then
6686 -- Decorate the component reference by setting its entity
6687 -- and type for resolution purposes.
6689 Set_Entity (Comp, Comp_Or_Discr);
6690 Set_Etype (Comp, Etype (Comp_Or_Discr));
6691 exit;
6692 end if;
6694 Comp_Or_Discr := Next_Entity (Comp_Or_Discr);
6695 end loop;
6697 -- Diagnose an illegal reference
6699 if Present (Comp_Or_Discr) then
6700 if Ekind (Comp_Or_Discr) = E_Discriminant then
6701 Error_Attr
6702 ("attribute % may not modify record discriminants", Comp);
6704 else pragma Assert (Ekind (Comp_Or_Discr) = E_Component);
6705 if Contains (Comps, Comp_Or_Discr) then
6706 Error_Msg_N ("component & already updated", Comp);
6708 -- Mark this component as processed
6710 else
6711 Append_New_Elmt (Comp_Or_Discr, Comps);
6712 end if;
6713 end if;
6715 -- The update aggregate mentions an entity that does not belong to
6716 -- the record type.
6718 else
6719 Error_Msg_N ("& is not a component of aggregate subtype", Comp);
6720 end if;
6722 -- Verify the consistency of types when the current component is
6723 -- part of a miltiple component update.
6725 -- Comp_1, ..., Comp_N => <value>
6727 if Present (Etype (Comp)) then
6728 Base_Typ := Base_Type (Etype (Comp));
6730 -- Save the type of the first component reference as the
6731 -- remaning references (if any) must resolve to this type.
6733 if No (Common_Typ) then
6734 Common_Typ := Base_Typ;
6736 elsif Base_Typ /= Common_Typ then
6737 Error_Msg_N
6738 ("components in choice list must have same type", Comp);
6739 end if;
6740 end if;
6741 end Analyze_Record_Component_Update;
6743 -- Local variables
6745 Assoc : Node_Id;
6746 Comp : Node_Id;
6748 -- Start of processing for Update
6750 begin
6751 Check_E1;
6753 if not Is_Object_Reference (P) then
6754 Error_Attr_P ("prefix of attribute % must denote an object");
6756 elsif not Is_Array_Type (P_Type)
6757 and then not Is_Record_Type (P_Type)
6758 then
6759 Error_Attr_P ("prefix of attribute % must be a record or array");
6761 elsif Is_Limited_View (P_Type) then
6762 Error_Attr ("prefix of attribute % cannot be limited", N);
6764 elsif Nkind (E1) /= N_Aggregate then
6765 Error_Attr ("attribute % requires component association list", N);
6766 end if;
6768 -- Inspect the update aggregate, looking at all the associations and
6769 -- choices. Perform the following checks:
6771 -- 1) Legality of "others" in all cases
6772 -- 2) Legality of <>
6773 -- 3) Component legality for arrays
6774 -- 4) Component legality for records
6776 -- The remaining checks are performed on the expanded attribute
6778 Assoc := First (Component_Associations (E1));
6779 while Present (Assoc) loop
6781 -- The use of <> is illegal (SPARK RM 4.4.1(1))
6783 if Box_Present (Assoc) then
6784 Error_Attr
6785 ("default initialization not allowed in attribute %", Assoc);
6787 -- Otherwise process the association
6789 else
6790 Analyze (Expression (Assoc));
6792 if Is_Array_Type (P_Type) then
6793 Analyze_Array_Component_Update (Assoc);
6795 elsif Is_Record_Type (P_Type) then
6797 -- Reset the common type used in a multiple component update
6798 -- as we are processing the contents of a new association.
6800 Common_Typ := Empty;
6802 Comp := First (Choices (Assoc));
6803 while Present (Comp) loop
6804 if Nkind (Comp) = N_Identifier then
6805 Analyze_Record_Component_Update (Comp);
6807 -- The use of others is illegal (SPARK RM 4.4.1(5))
6809 elsif Nkind (Comp) = N_Others_Choice then
6810 Error_Attr
6811 ("others choice not allowed in attribute %", Comp);
6813 -- The name of a record component cannot appear in any
6814 -- other form.
6816 else
6817 Error_Msg_N
6818 ("name should be identifier or OTHERS", Comp);
6819 end if;
6821 Next (Comp);
6822 end loop;
6823 end if;
6824 end if;
6826 Next (Assoc);
6827 end loop;
6829 -- The type of attribute 'Update is that of the prefix
6831 Set_Etype (N, P_Type);
6833 Sem_Warn.Warn_On_Suspicious_Update (N);
6834 end Update;
6836 ---------
6837 -- Val --
6838 ---------
6840 when Attribute_Val =>
6841 Check_E1;
6842 Check_Discrete_Type;
6844 if Is_Boolean_Type (P_Type) then
6845 Error_Msg_Name_1 := Aname;
6846 Error_Msg_Name_2 := Chars (P_Type);
6847 Check_SPARK_05_Restriction
6848 ("attribute% is not allowed for type%", P);
6849 end if;
6851 -- Note, we need a range check in general, but we wait for the
6852 -- Resolve call to do this, since we want to let Eval_Attribute
6853 -- have a chance to find an static illegality first.
6855 Resolve (E1, Any_Integer);
6856 Set_Etype (N, P_Base_Type);
6858 -----------
6859 -- Valid --
6860 -----------
6862 when Attribute_Valid =>
6863 Check_E0;
6865 -- Ignore check for object if we have a 'Valid reference generated
6866 -- by the expanded code, since in some cases valid checks can occur
6867 -- on items that are names, but are not objects (e.g. attributes).
6869 if Comes_From_Source (N) then
6870 Check_Object_Reference (P);
6871 end if;
6873 if not Is_Scalar_Type (P_Type) then
6874 Error_Attr_P ("object for % attribute must be of scalar type");
6875 end if;
6877 -- If the attribute appears within the subtype's own predicate
6878 -- function, then issue a warning that this will cause infinite
6879 -- recursion.
6881 declare
6882 Pred_Func : constant Entity_Id := Predicate_Function (P_Type);
6884 begin
6885 if Present (Pred_Func) and then Current_Scope = Pred_Func then
6886 Error_Msg_N
6887 ("attribute Valid requires a predicate check??", N);
6888 Error_Msg_N ("\and will result in infinite recursion??", N);
6889 end if;
6890 end;
6892 Set_Etype (N, Standard_Boolean);
6894 -------------------
6895 -- Valid_Scalars --
6896 -------------------
6898 when Attribute_Valid_Scalars =>
6899 Check_E0;
6900 Check_Object_Reference (P);
6901 Set_Etype (N, Standard_Boolean);
6903 -- Following checks are only for source types
6905 if Comes_From_Source (N) then
6906 if not Scalar_Part_Present (P_Type) then
6907 Error_Attr_P
6908 ("??attribute % always True, no scalars to check");
6909 end if;
6911 -- Not allowed for unchecked union type
6913 if Has_Unchecked_Union (P_Type) then
6914 Error_Attr_P
6915 ("attribute % not allowed for Unchecked_Union type");
6916 end if;
6917 end if;
6919 -----------
6920 -- Value --
6921 -----------
6923 when Attribute_Value =>
6924 Check_SPARK_05_Restriction_On_Attribute;
6925 Check_E1;
6926 Check_Scalar_Type;
6928 -- Case of enumeration type
6930 -- When an enumeration type appears in an attribute reference, all
6931 -- literals of the type are marked as referenced. This must only be
6932 -- done if the attribute reference appears in the current source.
6933 -- Otherwise the information on references may differ between a
6934 -- normal compilation and one that performs inlining.
6936 if Is_Enumeration_Type (P_Type)
6937 and then In_Extended_Main_Code_Unit (N)
6938 then
6939 Check_Restriction (No_Enumeration_Maps, N);
6941 -- Mark all enumeration literals as referenced, since the use of
6942 -- the Value attribute can implicitly reference any of the
6943 -- literals of the enumeration base type.
6945 declare
6946 Ent : Entity_Id := First_Literal (P_Base_Type);
6947 begin
6948 while Present (Ent) loop
6949 Set_Referenced (Ent);
6950 Next_Literal (Ent);
6951 end loop;
6952 end;
6953 end if;
6955 -- Set Etype before resolving expression because expansion of
6956 -- expression may require enclosing type. Note that the type
6957 -- returned by 'Value is the base type of the prefix type.
6959 Set_Etype (N, P_Base_Type);
6960 Validate_Non_Static_Attribute_Function_Call;
6962 -- Check restriction No_Fixed_IO
6964 if Restriction_Check_Required (No_Fixed_IO)
6965 and then Is_Fixed_Point_Type (P_Type)
6966 then
6967 Check_Restriction (No_Fixed_IO, P);
6968 end if;
6970 ----------------
6971 -- Value_Size --
6972 ----------------
6974 when Attribute_Value_Size =>
6975 Check_E0;
6976 Check_Type;
6977 Check_Not_Incomplete_Type;
6978 Set_Etype (N, Universal_Integer);
6980 -------------
6981 -- Version --
6982 -------------
6984 when Attribute_Version =>
6985 Check_E0;
6986 Check_Program_Unit;
6987 Set_Etype (N, RTE (RE_Version_String));
6989 ------------------
6990 -- Wchar_T_Size --
6991 ------------------
6993 when Attribute_Wchar_T_Size =>
6994 Standard_Attribute (Interfaces_Wchar_T_Size);
6996 ----------------
6997 -- Wide_Image --
6998 ----------------
7000 when Attribute_Wide_Image =>
7001 Analyze_Image_Attribute (Standard_Wide_String);
7003 ---------------------
7004 -- Wide_Wide_Image --
7005 ---------------------
7007 when Attribute_Wide_Wide_Image =>
7008 Analyze_Image_Attribute (Standard_Wide_Wide_String);
7010 ----------------
7011 -- Wide_Value --
7012 ----------------
7014 when Attribute_Wide_Value =>
7015 Check_SPARK_05_Restriction_On_Attribute;
7016 Check_E1;
7017 Check_Scalar_Type;
7019 -- Set Etype before resolving expression because expansion
7020 -- of expression may require enclosing type.
7022 Set_Etype (N, P_Type);
7023 Validate_Non_Static_Attribute_Function_Call;
7025 -- Check restriction No_Fixed_IO
7027 if Restriction_Check_Required (No_Fixed_IO)
7028 and then Is_Fixed_Point_Type (P_Type)
7029 then
7030 Check_Restriction (No_Fixed_IO, P);
7031 end if;
7033 ---------------------
7034 -- Wide_Wide_Value --
7035 ---------------------
7037 when Attribute_Wide_Wide_Value =>
7038 Check_E1;
7039 Check_Scalar_Type;
7041 -- Set Etype before resolving expression because expansion
7042 -- of expression may require enclosing type.
7044 Set_Etype (N, P_Type);
7045 Validate_Non_Static_Attribute_Function_Call;
7047 -- Check restriction No_Fixed_IO
7049 if Restriction_Check_Required (No_Fixed_IO)
7050 and then Is_Fixed_Point_Type (P_Type)
7051 then
7052 Check_Restriction (No_Fixed_IO, P);
7053 end if;
7055 ---------------------
7056 -- Wide_Wide_Width --
7057 ---------------------
7059 when Attribute_Wide_Wide_Width =>
7060 Check_E0;
7061 Check_Scalar_Type;
7062 Set_Etype (N, Universal_Integer);
7064 ----------------
7065 -- Wide_Width --
7066 ----------------
7068 when Attribute_Wide_Width =>
7069 Check_SPARK_05_Restriction_On_Attribute;
7070 Check_E0;
7071 Check_Scalar_Type;
7072 Set_Etype (N, Universal_Integer);
7074 -----------
7075 -- Width --
7076 -----------
7078 when Attribute_Width =>
7079 Check_SPARK_05_Restriction_On_Attribute;
7080 Check_E0;
7081 Check_Scalar_Type;
7082 Set_Etype (N, Universal_Integer);
7084 ---------------
7085 -- Word_Size --
7086 ---------------
7088 when Attribute_Word_Size =>
7089 Standard_Attribute (System_Word_Size);
7091 -----------
7092 -- Write --
7093 -----------
7095 when Attribute_Write =>
7096 Check_E2;
7097 Check_Stream_Attribute (TSS_Stream_Write);
7098 Set_Etype (N, Standard_Void_Type);
7099 Resolve (N, Standard_Void_Type);
7101 end case;
7103 -- In SPARK certain attributes (see below) depend on Tasking_State.
7104 -- Ensure that the entity is available for gnat2why by loading it.
7105 -- See SPARK RM 9(18) for the relevant rule.
7107 if GNATprove_Mode then
7108 declare
7109 Unused : Entity_Id;
7111 begin
7112 case Attr_Id is
7113 when Attribute_Callable
7114 | Attribute_Caller
7115 | Attribute_Count
7116 | Attribute_Terminated
7118 Unused := RTE (RE_Tasking_State);
7120 when others =>
7121 null;
7122 end case;
7123 end;
7124 end if;
7126 -- All errors raise Bad_Attribute, so that we get out before any further
7127 -- damage occurs when an error is detected (for example, if we check for
7128 -- one attribute expression, and the check succeeds, we want to be able
7129 -- to proceed securely assuming that an expression is in fact present.
7131 -- Note: we set the attribute analyzed in this case to prevent any
7132 -- attempt at reanalysis which could generate spurious error msgs.
7134 exception
7135 when Bad_Attribute =>
7136 Set_Analyzed (N);
7137 Set_Etype (N, Any_Type);
7138 return;
7139 end Analyze_Attribute;
7141 --------------------
7142 -- Eval_Attribute --
7143 --------------------
7145 procedure Eval_Attribute (N : Node_Id) is
7146 Loc : constant Source_Ptr := Sloc (N);
7147 Aname : constant Name_Id := Attribute_Name (N);
7148 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7149 P : constant Node_Id := Prefix (N);
7151 C_Type : constant Entity_Id := Etype (N);
7152 -- The type imposed by the context
7154 E1 : Node_Id;
7155 -- First expression, or Empty if none
7157 E2 : Node_Id;
7158 -- Second expression, or Empty if none
7160 P_Entity : Entity_Id;
7161 -- Entity denoted by prefix
7163 P_Type : Entity_Id;
7164 -- The type of the prefix
7166 P_Base_Type : Entity_Id;
7167 -- The base type of the prefix type
7169 P_Root_Type : Entity_Id;
7170 -- The root type of the prefix type
7172 Static : Boolean;
7173 -- True if the result is Static. This is set by the general processing
7174 -- to true if the prefix is static, and all expressions are static. It
7175 -- can be reset as processing continues for particular attributes. This
7176 -- flag can still be True if the reference raises a constraint error.
7177 -- Is_Static_Expression (N) is set to follow this value as it is set
7178 -- and we could always reference this, but it is convenient to have a
7179 -- simple short name to use, since it is frequently referenced.
7181 Lo_Bound, Hi_Bound : Node_Id;
7182 -- Expressions for low and high bounds of type or array index referenced
7183 -- by First, Last, or Length attribute for array, set by Set_Bounds.
7185 CE_Node : Node_Id;
7186 -- Constraint error node used if we have an attribute reference has
7187 -- an argument that raises a constraint error. In this case we replace
7188 -- the attribute with a raise constraint_error node. This is important
7189 -- processing, since otherwise gigi might see an attribute which it is
7190 -- unprepared to deal with.
7192 procedure Check_Concurrent_Discriminant (Bound : Node_Id);
7193 -- If Bound is a reference to a discriminant of a task or protected type
7194 -- occurring within the object's body, rewrite attribute reference into
7195 -- a reference to the corresponding discriminal. Use for the expansion
7196 -- of checks against bounds of entry family index subtypes.
7198 procedure Check_Expressions;
7199 -- In case where the attribute is not foldable, the expressions, if
7200 -- any, of the attribute, are in a non-static context. This procedure
7201 -- performs the required additional checks.
7203 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
7204 -- Determines if the given type has compile time known bounds. Note
7205 -- that we enter the case statement even in cases where the prefix
7206 -- type does NOT have known bounds, so it is important to guard any
7207 -- attempt to evaluate both bounds with a call to this function.
7209 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
7210 -- This procedure is called when the attribute N has a non-static
7211 -- but compile time known value given by Val. It includes the
7212 -- necessary checks for out of range values.
7214 function Fore_Value return Nat;
7215 -- Computes the Fore value for the current attribute prefix, which is
7216 -- known to be a static fixed-point type. Used by Fore and Width.
7218 function Mantissa return Uint;
7219 -- Returns the Mantissa value for the prefix type
7221 procedure Set_Bounds;
7222 -- Used for First, Last and Length attributes applied to an array or
7223 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
7224 -- and high bound expressions for the index referenced by the attribute
7225 -- designator (i.e. the first index if no expression is present, and the
7226 -- N'th index if the value N is present as an expression). Also used for
7227 -- First and Last of scalar types and for First_Valid and Last_Valid.
7228 -- Static is reset to False if the type or index type is not statically
7229 -- constrained.
7231 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
7232 -- Verify that the prefix of a potentially static array attribute
7233 -- satisfies the conditions of 4.9 (14).
7235 -----------------------------------
7236 -- Check_Concurrent_Discriminant --
7237 -----------------------------------
7239 procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
7240 Tsk : Entity_Id;
7241 -- The concurrent (task or protected) type
7243 begin
7244 if Nkind (Bound) = N_Identifier
7245 and then Ekind (Entity (Bound)) = E_Discriminant
7246 and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
7247 then
7248 Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
7250 if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
7252 -- Find discriminant of original concurrent type, and use
7253 -- its current discriminal, which is the renaming within
7254 -- the task/protected body.
7256 Rewrite (N,
7257 New_Occurrence_Of
7258 (Find_Body_Discriminal (Entity (Bound)), Loc));
7259 end if;
7260 end if;
7261 end Check_Concurrent_Discriminant;
7263 -----------------------
7264 -- Check_Expressions --
7265 -----------------------
7267 procedure Check_Expressions is
7268 E : Node_Id;
7269 begin
7270 E := E1;
7271 while Present (E) loop
7272 Check_Non_Static_Context (E);
7273 Next (E);
7274 end loop;
7275 end Check_Expressions;
7277 ----------------------------------
7278 -- Compile_Time_Known_Attribute --
7279 ----------------------------------
7281 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
7282 T : constant Entity_Id := Etype (N);
7284 begin
7285 Fold_Uint (N, Val, False);
7287 -- Check that result is in bounds of the type if it is static
7289 if Is_In_Range (N, T, Assume_Valid => False) then
7290 null;
7292 elsif Is_Out_Of_Range (N, T) then
7293 Apply_Compile_Time_Constraint_Error
7294 (N, "value not in range of}??", CE_Range_Check_Failed);
7296 elsif not Range_Checks_Suppressed (T) then
7297 Enable_Range_Check (N);
7299 else
7300 Set_Do_Range_Check (N, False);
7301 end if;
7302 end Compile_Time_Known_Attribute;
7304 -------------------------------
7305 -- Compile_Time_Known_Bounds --
7306 -------------------------------
7308 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
7309 begin
7310 return
7311 Compile_Time_Known_Value (Type_Low_Bound (Typ))
7312 and then
7313 Compile_Time_Known_Value (Type_High_Bound (Typ));
7314 end Compile_Time_Known_Bounds;
7316 ----------------
7317 -- Fore_Value --
7318 ----------------
7320 -- Note that the Fore calculation is based on the actual values
7321 -- of the bounds, and does not take into account possible rounding.
7323 function Fore_Value return Nat is
7324 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7325 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7326 Small : constant Ureal := Small_Value (P_Type);
7327 Lo_Real : constant Ureal := Lo * Small;
7328 Hi_Real : constant Ureal := Hi * Small;
7329 T : Ureal;
7330 R : Nat;
7332 begin
7333 -- Bounds are given in terms of small units, so first compute
7334 -- proper values as reals.
7336 T := UR_Max (abs Lo_Real, abs Hi_Real);
7337 R := 2;
7339 -- Loop to compute proper value if more than one digit required
7341 while T >= Ureal_10 loop
7342 R := R + 1;
7343 T := T / Ureal_10;
7344 end loop;
7346 return R;
7347 end Fore_Value;
7349 --------------
7350 -- Mantissa --
7351 --------------
7353 -- Table of mantissa values accessed by function Computed using
7354 -- the relation:
7356 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
7358 -- where D is T'Digits (RM83 3.5.7)
7360 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
7361 1 => 5,
7362 2 => 8,
7363 3 => 11,
7364 4 => 15,
7365 5 => 18,
7366 6 => 21,
7367 7 => 25,
7368 8 => 28,
7369 9 => 31,
7370 10 => 35,
7371 11 => 38,
7372 12 => 41,
7373 13 => 45,
7374 14 => 48,
7375 15 => 51,
7376 16 => 55,
7377 17 => 58,
7378 18 => 61,
7379 19 => 65,
7380 20 => 68,
7381 21 => 71,
7382 22 => 75,
7383 23 => 78,
7384 24 => 81,
7385 25 => 85,
7386 26 => 88,
7387 27 => 91,
7388 28 => 95,
7389 29 => 98,
7390 30 => 101,
7391 31 => 104,
7392 32 => 108,
7393 33 => 111,
7394 34 => 114,
7395 35 => 118,
7396 36 => 121,
7397 37 => 124,
7398 38 => 128,
7399 39 => 131,
7400 40 => 134);
7402 function Mantissa return Uint is
7403 begin
7404 return
7405 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
7406 end Mantissa;
7408 ----------------
7409 -- Set_Bounds --
7410 ----------------
7412 procedure Set_Bounds is
7413 Ndim : Nat;
7414 Indx : Node_Id;
7415 Ityp : Entity_Id;
7417 begin
7418 -- For a string literal subtype, we have to construct the bounds.
7419 -- Valid Ada code never applies attributes to string literals, but
7420 -- it is convenient to allow the expander to generate attribute
7421 -- references of this type (e.g. First and Last applied to a string
7422 -- literal).
7424 -- Note that the whole point of the E_String_Literal_Subtype is to
7425 -- avoid this construction of bounds, but the cases in which we
7426 -- have to materialize them are rare enough that we don't worry.
7428 -- The low bound is simply the low bound of the base type. The
7429 -- high bound is computed from the length of the string and this
7430 -- low bound.
7432 if Ekind (P_Type) = E_String_Literal_Subtype then
7433 Ityp := Etype (First_Index (Base_Type (P_Type)));
7434 Lo_Bound := Type_Low_Bound (Ityp);
7436 Hi_Bound :=
7437 Make_Integer_Literal (Sloc (P),
7438 Intval =>
7439 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
7441 Set_Parent (Hi_Bound, P);
7442 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
7443 return;
7445 -- For non-array case, just get bounds of scalar type
7447 elsif Is_Scalar_Type (P_Type) then
7448 Ityp := P_Type;
7450 -- For a fixed-point type, we must freeze to get the attributes
7451 -- of the fixed-point type set now so we can reference them.
7453 if Is_Fixed_Point_Type (P_Type)
7454 and then not Is_Frozen (Base_Type (P_Type))
7455 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
7456 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
7457 then
7458 Freeze_Fixed_Point_Type (Base_Type (P_Type));
7459 end if;
7461 -- For array case, get type of proper index
7463 else
7464 if No (E1) then
7465 Ndim := 1;
7466 else
7467 Ndim := UI_To_Int (Expr_Value (E1));
7468 end if;
7470 Indx := First_Index (P_Type);
7471 for J in 1 .. Ndim - 1 loop
7472 Next_Index (Indx);
7473 end loop;
7475 -- If no index type, get out (some other error occurred, and
7476 -- we don't have enough information to complete the job).
7478 if No (Indx) then
7479 Lo_Bound := Error;
7480 Hi_Bound := Error;
7481 return;
7482 end if;
7484 Ityp := Etype (Indx);
7485 end if;
7487 -- A discrete range in an index constraint is allowed to be a
7488 -- subtype indication. This is syntactically a pain, but should
7489 -- not propagate to the entity for the corresponding index subtype.
7490 -- After checking that the subtype indication is legal, the range
7491 -- of the subtype indication should be transfered to the entity.
7492 -- The attributes for the bounds should remain the simple retrievals
7493 -- that they are now.
7495 Lo_Bound := Type_Low_Bound (Ityp);
7496 Hi_Bound := Type_High_Bound (Ityp);
7498 -- If subtype is non-static, result is definitely non-static
7500 if not Is_Static_Subtype (Ityp) then
7501 Static := False;
7502 Set_Is_Static_Expression (N, False);
7504 -- Subtype is static, does it raise CE?
7506 elsif not Is_OK_Static_Subtype (Ityp) then
7507 Set_Raises_Constraint_Error (N);
7508 end if;
7509 end Set_Bounds;
7511 -------------------------------
7512 -- Statically_Denotes_Entity --
7513 -------------------------------
7515 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
7516 E : Entity_Id;
7518 begin
7519 if not Is_Entity_Name (N) then
7520 return False;
7521 else
7522 E := Entity (N);
7523 end if;
7525 return
7526 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
7527 or else Statically_Denotes_Entity (Renamed_Object (E));
7528 end Statically_Denotes_Entity;
7530 -- Start of processing for Eval_Attribute
7532 begin
7533 -- Initialize result as non-static, will be reset if appropriate
7535 Set_Is_Static_Expression (N, False);
7536 Static := False;
7538 -- Acquire first two expressions (at the moment, no attributes take more
7539 -- than two expressions in any case).
7541 if Present (Expressions (N)) then
7542 E1 := First (Expressions (N));
7543 E2 := Next (E1);
7544 else
7545 E1 := Empty;
7546 E2 := Empty;
7547 end if;
7549 -- Special processing for Enabled attribute. This attribute has a very
7550 -- special prefix, and the easiest way to avoid lots of special checks
7551 -- to protect this special prefix from causing trouble is to deal with
7552 -- this attribute immediately and be done with it.
7554 if Id = Attribute_Enabled then
7556 -- We skip evaluation if the expander is not active. This is not just
7557 -- an optimization. It is of key importance that we not rewrite the
7558 -- attribute in a generic template, since we want to pick up the
7559 -- setting of the check in the instance, Testing Expander_Active
7560 -- might seem an easy way of doing this, but we need to account for
7561 -- ASIS needs, so check explicitly for a generic context.
7563 if not Inside_A_Generic then
7564 declare
7565 C : constant Check_Id := Get_Check_Id (Chars (P));
7566 R : Boolean;
7568 begin
7569 if No (E1) then
7570 if C in Predefined_Check_Id then
7571 R := Scope_Suppress.Suppress (C);
7572 else
7573 R := Is_Check_Suppressed (Empty, C);
7574 end if;
7576 else
7577 R := Is_Check_Suppressed (Entity (E1), C);
7578 end if;
7580 Rewrite (N, New_Occurrence_Of (Boolean_Literals (not R), Loc));
7581 end;
7582 end if;
7584 return;
7585 end if;
7587 -- Attribute 'Img applied to a static enumeration value is static, and
7588 -- we will do the folding right here (things get confused if we let this
7589 -- case go through the normal circuitry).
7591 if Attribute_Name (N) = Name_Img
7592 and then Is_Entity_Name (P)
7593 and then Is_Enumeration_Type (Etype (Entity (P)))
7594 and then Is_OK_Static_Expression (P)
7595 then
7596 declare
7597 Lit : constant Entity_Id := Expr_Value_E (P);
7598 Str : String_Id;
7600 begin
7601 Start_String;
7602 Get_Unqualified_Decoded_Name_String (Chars (Lit));
7603 Set_Casing (All_Upper_Case);
7604 Store_String_Chars (Name_Buffer (1 .. Name_Len));
7605 Str := End_String;
7607 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
7608 Analyze_And_Resolve (N, Standard_String);
7609 Set_Is_Static_Expression (N, True);
7610 end;
7612 return;
7613 end if;
7615 -- Special processing for cases where the prefix is an object. For this
7616 -- purpose, a string literal counts as an object (attributes of string
7617 -- literals can only appear in generated code).
7619 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
7621 -- For Component_Size, the prefix is an array object, and we apply
7622 -- the attribute to the type of the object. This is allowed for both
7623 -- unconstrained and constrained arrays, since the bounds have no
7624 -- influence on the value of this attribute.
7626 if Id = Attribute_Component_Size then
7627 P_Entity := Etype (P);
7629 -- For Enum_Rep, evaluation depends on the nature of the prefix and
7630 -- the optional argument.
7632 elsif Id = Attribute_Enum_Rep then
7633 if Is_Entity_Name (P) then
7635 declare
7636 Enum_Expr : Node_Id;
7637 -- The enumeration-type expression of interest
7639 begin
7640 -- P'Enum_Rep case
7642 if Ekind_In (Entity (P), E_Constant,
7643 E_Enumeration_Literal)
7644 then
7645 Enum_Expr := P;
7647 -- Enum_Type'Enum_Rep (E1) case
7649 elsif Is_Enumeration_Type (Entity (P)) then
7650 Enum_Expr := E1;
7652 -- Otherwise the attribute must be expanded into a
7653 -- conversion and evaluated at run time.
7655 else
7656 Check_Expressions;
7657 return;
7658 end if;
7660 -- We can fold if the expression is an enumeration
7661 -- literal, or if it denotes a constant whose value
7662 -- is known at compile time.
7664 if Nkind (Enum_Expr) in N_Has_Entity
7665 and then (Ekind (Entity (Enum_Expr)) =
7666 E_Enumeration_Literal
7667 or else
7668 (Ekind (Entity (Enum_Expr)) = E_Constant
7669 and then Nkind (Parent (Entity (Enum_Expr))) =
7670 N_Object_Declaration
7671 and then Compile_Time_Known_Value
7672 (Expression (Parent (Entity (P))))))
7673 then
7674 P_Entity := Etype (P);
7675 else
7676 Check_Expressions;
7677 return;
7678 end if;
7679 end;
7681 -- Otherwise the attribute is illegal, do not attempt to perform
7682 -- any kind of folding.
7684 else
7685 return;
7686 end if;
7688 -- For First and Last, the prefix is an array object, and we apply
7689 -- the attribute to the type of the array, but we need a constrained
7690 -- type for this, so we use the actual subtype if available.
7692 elsif Id = Attribute_First or else
7693 Id = Attribute_Last or else
7694 Id = Attribute_Length
7695 then
7696 declare
7697 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
7699 begin
7700 if Present (AS) and then Is_Constrained (AS) then
7701 P_Entity := AS;
7703 -- If we have an unconstrained type we cannot fold
7705 else
7706 Check_Expressions;
7707 return;
7708 end if;
7709 end;
7711 -- For Size, give size of object if available, otherwise we
7712 -- cannot fold Size.
7714 elsif Id = Attribute_Size then
7715 if Is_Entity_Name (P)
7716 and then Known_Esize (Entity (P))
7717 then
7718 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
7719 return;
7721 else
7722 Check_Expressions;
7723 return;
7724 end if;
7726 -- For Alignment, give size of object if available, otherwise we
7727 -- cannot fold Alignment.
7729 elsif Id = Attribute_Alignment then
7730 if Is_Entity_Name (P)
7731 and then Known_Alignment (Entity (P))
7732 then
7733 Fold_Uint (N, Alignment (Entity (P)), Static);
7734 return;
7736 else
7737 Check_Expressions;
7738 return;
7739 end if;
7741 -- For Lock_Free, we apply the attribute to the type of the object.
7742 -- This is allowed since we have already verified that the type is a
7743 -- protected type.
7745 elsif Id = Attribute_Lock_Free then
7746 P_Entity := Etype (P);
7748 -- No other attributes for objects are folded
7750 else
7751 Check_Expressions;
7752 return;
7753 end if;
7755 -- Cases where P is not an object. Cannot do anything if P is not the
7756 -- name of an entity.
7758 elsif not Is_Entity_Name (P) then
7759 Check_Expressions;
7760 return;
7762 -- Otherwise get prefix entity
7764 else
7765 P_Entity := Entity (P);
7766 end if;
7768 -- If we are asked to evaluate an attribute where the prefix is a
7769 -- non-frozen generic actual type whose RM_Size is still set to zero,
7770 -- then abandon the effort.
7772 if Is_Type (P_Entity)
7773 and then (not Is_Frozen (P_Entity)
7774 and then Is_Generic_Actual_Type (P_Entity)
7775 and then RM_Size (P_Entity) = 0)
7777 -- However, the attribute Unconstrained_Array must be evaluated,
7778 -- since it is documented to be a static attribute (and can for
7779 -- example appear in a Compile_Time_Warning pragma). The frozen
7780 -- status of the type does not affect its evaluation.
7782 and then Id /= Attribute_Unconstrained_Array
7783 then
7784 return;
7785 end if;
7787 -- At this stage P_Entity is the entity to which the attribute
7788 -- is to be applied. This is usually simply the entity of the
7789 -- prefix, except in some cases of attributes for objects, where
7790 -- as described above, we apply the attribute to the object type.
7792 -- Here is where we make sure that static attributes are properly
7793 -- marked as such. These are attributes whose prefix is a static
7794 -- scalar subtype, whose result is scalar, and whose arguments, if
7795 -- present, are static scalar expressions. Note that such references
7796 -- are static expressions even if they raise Constraint_Error.
7798 -- For example, Boolean'Pos (1/0 = 0) is a static expression, even
7799 -- though evaluating it raises constraint error. This means that a
7800 -- declaration like:
7802 -- X : constant := (if True then 1 else Boolean'Pos (1/0 = 0));
7804 -- is legal, since here this expression appears in a statically
7805 -- unevaluated position, so it does not actually raise an exception.
7807 if Is_Scalar_Type (P_Entity)
7808 and then (not Is_Generic_Type (P_Entity))
7809 and then Is_Static_Subtype (P_Entity)
7810 and then Is_Scalar_Type (Etype (N))
7811 and then
7812 (No (E1)
7813 or else (Is_Static_Expression (E1)
7814 and then Is_Scalar_Type (Etype (E1))))
7815 and then
7816 (No (E2)
7817 or else (Is_Static_Expression (E2)
7818 and then Is_Scalar_Type (Etype (E1))))
7819 then
7820 Static := True;
7821 Set_Is_Static_Expression (N, True);
7822 end if;
7824 -- First foldable possibility is a scalar or array type (RM 4.9(7))
7825 -- that is not generic (generic types are eliminated by RM 4.9(25)).
7826 -- Note we allow non-static non-generic types at this stage as further
7827 -- described below.
7829 if Is_Type (P_Entity)
7830 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
7831 and then (not Is_Generic_Type (P_Entity))
7832 then
7833 P_Type := P_Entity;
7835 -- Second foldable possibility is an array object (RM 4.9(8))
7837 elsif Ekind_In (P_Entity, E_Variable, E_Constant)
7838 and then Is_Array_Type (Etype (P_Entity))
7839 and then (not Is_Generic_Type (Etype (P_Entity)))
7840 then
7841 P_Type := Etype (P_Entity);
7843 -- If the entity is an array constant with an unconstrained nominal
7844 -- subtype then get the type from the initial value. If the value has
7845 -- been expanded into assignments, there is no expression and the
7846 -- attribute reference remains dynamic.
7848 -- We could do better here and retrieve the type ???
7850 if Ekind (P_Entity) = E_Constant
7851 and then not Is_Constrained (P_Type)
7852 then
7853 if No (Constant_Value (P_Entity)) then
7854 return;
7855 else
7856 P_Type := Etype (Constant_Value (P_Entity));
7857 end if;
7858 end if;
7860 -- Definite must be folded if the prefix is not a generic type, that
7861 -- is to say if we are within an instantiation. Same processing applies
7862 -- to the GNAT attributes Atomic_Always_Lock_Free, Has_Discriminants,
7863 -- Lock_Free, Type_Class, Has_Tagged_Value, and Unconstrained_Array.
7865 elsif (Id = Attribute_Atomic_Always_Lock_Free or else
7866 Id = Attribute_Definite or else
7867 Id = Attribute_Has_Access_Values or else
7868 Id = Attribute_Has_Discriminants or else
7869 Id = Attribute_Has_Tagged_Values or else
7870 Id = Attribute_Lock_Free or else
7871 Id = Attribute_Type_Class or else
7872 Id = Attribute_Unconstrained_Array or else
7873 Id = Attribute_Max_Alignment_For_Allocation)
7874 and then not Is_Generic_Type (P_Entity)
7875 then
7876 P_Type := P_Entity;
7878 -- We can fold 'Size applied to a type if the size is known (as happens
7879 -- for a size from an attribute definition clause). At this stage, this
7880 -- can happen only for types (e.g. record types) for which the size is
7881 -- always non-static. We exclude generic types from consideration (since
7882 -- they have bogus sizes set within templates).
7884 elsif Id = Attribute_Size
7885 and then Is_Type (P_Entity)
7886 and then (not Is_Generic_Type (P_Entity))
7887 and then Known_Static_RM_Size (P_Entity)
7888 then
7889 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
7890 return;
7892 -- We can fold 'Alignment applied to a type if the alignment is known
7893 -- (as happens for an alignment from an attribute definition clause).
7894 -- At this stage, this can happen only for types (e.g. record types) for
7895 -- which the size is always non-static. We exclude generic types from
7896 -- consideration (since they have bogus sizes set within templates).
7898 elsif Id = Attribute_Alignment
7899 and then Is_Type (P_Entity)
7900 and then (not Is_Generic_Type (P_Entity))
7901 and then Known_Alignment (P_Entity)
7902 then
7903 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
7904 return;
7906 -- If this is an access attribute that is known to fail accessibility
7907 -- check, rewrite accordingly.
7909 elsif Attribute_Name (N) = Name_Access
7910 and then Raises_Constraint_Error (N)
7911 then
7912 Rewrite (N,
7913 Make_Raise_Program_Error (Loc,
7914 Reason => PE_Accessibility_Check_Failed));
7915 Set_Etype (N, C_Type);
7916 return;
7918 -- No other cases are foldable (they certainly aren't static, and at
7919 -- the moment we don't try to fold any cases other than the ones above).
7921 else
7922 Check_Expressions;
7923 return;
7924 end if;
7926 -- If either attribute or the prefix is Any_Type, then propagate
7927 -- Any_Type to the result and don't do anything else at all.
7929 if P_Type = Any_Type
7930 or else (Present (E1) and then Etype (E1) = Any_Type)
7931 or else (Present (E2) and then Etype (E2) = Any_Type)
7932 then
7933 Set_Etype (N, Any_Type);
7934 return;
7935 end if;
7937 -- Scalar subtype case. We have not yet enforced the static requirement
7938 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
7939 -- of non-static attribute references (e.g. S'Digits for a non-static
7940 -- floating-point type, which we can compute at compile time).
7942 -- Note: this folding of non-static attributes is not simply a case of
7943 -- optimization. For many of the attributes affected, Gigi cannot handle
7944 -- the attribute and depends on the front end having folded them away.
7946 -- Note: although we don't require staticness at this stage, we do set
7947 -- the Static variable to record the staticness, for easy reference by
7948 -- those attributes where it matters (e.g. Succ and Pred), and also to
7949 -- be used to ensure that non-static folded things are not marked as
7950 -- being static (a check that is done right at the end).
7952 P_Root_Type := Root_Type (P_Type);
7953 P_Base_Type := Base_Type (P_Type);
7955 -- If the root type or base type is generic, then we cannot fold. This
7956 -- test is needed because subtypes of generic types are not always
7957 -- marked as being generic themselves (which seems odd???)
7959 if Is_Generic_Type (P_Root_Type)
7960 or else Is_Generic_Type (P_Base_Type)
7961 then
7962 return;
7963 end if;
7965 if Is_Scalar_Type (P_Type) then
7966 if not Is_Static_Subtype (P_Type) then
7967 Static := False;
7968 Set_Is_Static_Expression (N, False);
7969 elsif not Is_OK_Static_Subtype (P_Type) then
7970 Set_Raises_Constraint_Error (N);
7971 end if;
7973 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
7974 -- since we can't do anything with unconstrained arrays. In addition,
7975 -- only the First, Last and Length attributes are possibly static.
7977 -- Atomic_Always_Lock_Free, Definite, Has_Access_Values,
7978 -- Has_Discriminants, Has_Tagged_Values, Lock_Free, Type_Class, and
7979 -- Unconstrained_Array are again exceptions, because they apply as well
7980 -- to unconstrained types.
7982 -- In addition Component_Size is an exception since it is possibly
7983 -- foldable, even though it is never static, and it does apply to
7984 -- unconstrained arrays. Furthermore, it is essential to fold this
7985 -- in the packed case, since otherwise the value will be incorrect.
7987 elsif Id = Attribute_Atomic_Always_Lock_Free or else
7988 Id = Attribute_Definite or else
7989 Id = Attribute_Has_Access_Values or else
7990 Id = Attribute_Has_Discriminants or else
7991 Id = Attribute_Has_Tagged_Values or else
7992 Id = Attribute_Lock_Free or else
7993 Id = Attribute_Type_Class or else
7994 Id = Attribute_Unconstrained_Array or else
7995 Id = Attribute_Component_Size
7996 then
7997 Static := False;
7998 Set_Is_Static_Expression (N, False);
8000 elsif Id /= Attribute_Max_Alignment_For_Allocation then
8001 if not Is_Constrained (P_Type)
8002 or else (Id /= Attribute_First and then
8003 Id /= Attribute_Last and then
8004 Id /= Attribute_Length)
8005 then
8006 Check_Expressions;
8007 return;
8008 end if;
8010 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
8011 -- scalar case, we hold off on enforcing staticness, since there are
8012 -- cases which we can fold at compile time even though they are not
8013 -- static (e.g. 'Length applied to a static index, even though other
8014 -- non-static indexes make the array type non-static). This is only
8015 -- an optimization, but it falls out essentially free, so why not.
8016 -- Again we compute the variable Static for easy reference later
8017 -- (note that no array attributes are static in Ada 83).
8019 -- We also need to set Static properly for subsequent legality checks
8020 -- which might otherwise accept non-static constants in contexts
8021 -- where they are not legal.
8023 Static :=
8024 Ada_Version >= Ada_95 and then Statically_Denotes_Entity (P);
8025 Set_Is_Static_Expression (N, Static);
8027 declare
8028 Nod : Node_Id;
8030 begin
8031 Nod := First_Index (P_Type);
8033 -- The expression is static if the array type is constrained
8034 -- by given bounds, and not by an initial expression. Constant
8035 -- strings are static in any case.
8037 if Root_Type (P_Type) /= Standard_String then
8038 Static :=
8039 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
8040 Set_Is_Static_Expression (N, Static);
8041 end if;
8043 while Present (Nod) loop
8044 if not Is_Static_Subtype (Etype (Nod)) then
8045 Static := False;
8046 Set_Is_Static_Expression (N, False);
8048 elsif not Is_OK_Static_Subtype (Etype (Nod)) then
8049 Set_Raises_Constraint_Error (N);
8050 Static := False;
8051 Set_Is_Static_Expression (N, False);
8052 end if;
8054 -- If however the index type is generic, or derived from
8055 -- one, attributes cannot be folded.
8057 if Is_Generic_Type (Root_Type (Etype (Nod)))
8058 and then Id /= Attribute_Component_Size
8059 then
8060 return;
8061 end if;
8063 Next_Index (Nod);
8064 end loop;
8065 end;
8066 end if;
8068 -- Check any expressions that are present. Note that these expressions,
8069 -- depending on the particular attribute type, are either part of the
8070 -- attribute designator, or they are arguments in a case where the
8071 -- attribute reference returns a function. In the latter case, the
8072 -- rule in (RM 4.9(22)) applies and in particular requires the type
8073 -- of the expressions to be scalar in order for the attribute to be
8074 -- considered to be static.
8076 declare
8077 E : Node_Id;
8079 begin
8080 E := E1;
8082 while Present (E) loop
8084 -- If expression is not static, then the attribute reference
8085 -- result certainly cannot be static.
8087 if not Is_Static_Expression (E) then
8088 Static := False;
8089 Set_Is_Static_Expression (N, False);
8090 end if;
8092 if Raises_Constraint_Error (E) then
8093 Set_Raises_Constraint_Error (N);
8094 end if;
8096 -- If the result is not known at compile time, or is not of
8097 -- a scalar type, then the result is definitely not static,
8098 -- so we can quit now.
8100 if not Compile_Time_Known_Value (E)
8101 or else not Is_Scalar_Type (Etype (E))
8102 then
8103 -- An odd special case, if this is a Pos attribute, this
8104 -- is where we need to apply a range check since it does
8105 -- not get done anywhere else.
8107 if Id = Attribute_Pos then
8108 if Is_Integer_Type (Etype (E)) then
8109 Apply_Range_Check (E, Etype (N));
8110 end if;
8111 end if;
8113 Check_Expressions;
8114 return;
8116 -- If the expression raises a constraint error, then so does
8117 -- the attribute reference. We keep going in this case because
8118 -- we are still interested in whether the attribute reference
8119 -- is static even if it is not static.
8121 elsif Raises_Constraint_Error (E) then
8122 Set_Raises_Constraint_Error (N);
8123 end if;
8125 Next (E);
8126 end loop;
8128 if Raises_Constraint_Error (Prefix (N)) then
8129 Set_Is_Static_Expression (N, False);
8130 return;
8131 end if;
8132 end;
8134 -- Deal with the case of a static attribute reference that raises
8135 -- constraint error. The Raises_Constraint_Error flag will already
8136 -- have been set, and the Static flag shows whether the attribute
8137 -- reference is static. In any case we certainly can't fold such an
8138 -- attribute reference.
8140 -- Note that the rewriting of the attribute node with the constraint
8141 -- error node is essential in this case, because otherwise Gigi might
8142 -- blow up on one of the attributes it never expects to see.
8144 -- The constraint_error node must have the type imposed by the context,
8145 -- to avoid spurious errors in the enclosing expression.
8147 if Raises_Constraint_Error (N) then
8148 CE_Node :=
8149 Make_Raise_Constraint_Error (Sloc (N),
8150 Reason => CE_Range_Check_Failed);
8151 Set_Etype (CE_Node, Etype (N));
8152 Set_Raises_Constraint_Error (CE_Node);
8153 Check_Expressions;
8154 Rewrite (N, Relocate_Node (CE_Node));
8155 Set_Raises_Constraint_Error (N, True);
8156 return;
8157 end if;
8159 -- At this point we have a potentially foldable attribute reference.
8160 -- If Static is set, then the attribute reference definitely obeys
8161 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
8162 -- folded. If Static is not set, then the attribute may or may not
8163 -- be foldable, and the individual attribute processing routines
8164 -- test Static as required in cases where it makes a difference.
8166 -- In the case where Static is not set, we do know that all the
8167 -- expressions present are at least known at compile time (we assumed
8168 -- above that if this was not the case, then there was no hope of static
8169 -- evaluation). However, we did not require that the bounds of the
8170 -- prefix type be compile time known, let alone static). That's because
8171 -- there are many attributes that can be computed at compile time on
8172 -- non-static subtypes, even though such references are not static
8173 -- expressions.
8175 -- For VAX float, the root type is an IEEE type. So make sure to use the
8176 -- base type instead of the root-type for floating point attributes.
8178 case Id is
8180 -- Attributes related to Ada 2012 iterators; nothing to evaluate for
8181 -- these.
8183 when Attribute_Constant_Indexing
8184 | Attribute_Default_Iterator
8185 | Attribute_Implicit_Dereference
8186 | Attribute_Iterator_Element
8187 | Attribute_Iterable
8188 | Attribute_Variable_Indexing
8190 null;
8192 -- Internal attributes used to deal with Ada 2012 delayed aspects.
8193 -- These were already rejected by the parser. Thus they shouldn't
8194 -- appear here.
8196 when Internal_Attribute_Id =>
8197 raise Program_Error;
8199 --------------
8200 -- Adjacent --
8201 --------------
8203 when Attribute_Adjacent =>
8204 Fold_Ureal
8206 Eval_Fat.Adjacent
8207 (P_Base_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
8208 Static);
8210 ---------
8211 -- Aft --
8212 ---------
8214 when Attribute_Aft =>
8215 Fold_Uint (N, Aft_Value (P_Type), Static);
8217 ---------------
8218 -- Alignment --
8219 ---------------
8221 when Attribute_Alignment => Alignment_Block : declare
8222 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
8224 begin
8225 -- Fold if alignment is set and not otherwise
8227 if Known_Alignment (P_TypeA) then
8228 Fold_Uint (N, Alignment (P_TypeA), Static);
8229 end if;
8230 end Alignment_Block;
8232 -----------------------------
8233 -- Atomic_Always_Lock_Free --
8234 -----------------------------
8236 -- Atomic_Always_Lock_Free attribute is a Boolean, thus no need to fold
8237 -- here.
8239 when Attribute_Atomic_Always_Lock_Free => Atomic_Always_Lock_Free :
8240 declare
8241 V : constant Entity_Id :=
8242 Boolean_Literals
8243 (Support_Atomic_Primitives_On_Target
8244 and then Support_Atomic_Primitives (P_Type));
8246 begin
8247 Rewrite (N, New_Occurrence_Of (V, Loc));
8249 -- Analyze and resolve as boolean. Note that this attribute is a
8250 -- static attribute in GNAT.
8252 Analyze_And_Resolve (N, Standard_Boolean);
8253 Static := True;
8254 Set_Is_Static_Expression (N, True);
8255 end Atomic_Always_Lock_Free;
8257 ---------
8258 -- Bit --
8259 ---------
8261 -- Bit can never be folded
8263 when Attribute_Bit =>
8264 null;
8266 ------------------
8267 -- Body_Version --
8268 ------------------
8270 -- Body_version can never be static
8272 when Attribute_Body_Version =>
8273 null;
8275 -------------
8276 -- Ceiling --
8277 -------------
8279 when Attribute_Ceiling =>
8280 Fold_Ureal
8281 (N, Eval_Fat.Ceiling (P_Base_Type, Expr_Value_R (E1)), Static);
8283 --------------------
8284 -- Component_Size --
8285 --------------------
8287 when Attribute_Component_Size =>
8288 if Known_Static_Component_Size (P_Type) then
8289 Fold_Uint (N, Component_Size (P_Type), Static);
8290 end if;
8292 -------------
8293 -- Compose --
8294 -------------
8296 when Attribute_Compose =>
8297 Fold_Ureal
8299 Eval_Fat.Compose (P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)),
8300 Static);
8302 -----------------
8303 -- Constrained --
8304 -----------------
8306 -- Constrained is never folded for now, there may be cases that
8307 -- could be handled at compile time. To be looked at later.
8309 when Attribute_Constrained =>
8311 -- The expander might fold it and set the static flag accordingly,
8312 -- but with expansion disabled (as in ASIS), it remains as an
8313 -- attribute reference, and this reference is not static.
8315 Set_Is_Static_Expression (N, False);
8316 null;
8318 ---------------
8319 -- Copy_Sign --
8320 ---------------
8322 when Attribute_Copy_Sign =>
8323 Fold_Ureal
8325 Eval_Fat.Copy_Sign
8326 (P_Base_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
8327 Static);
8329 --------------
8330 -- Definite --
8331 --------------
8333 when Attribute_Definite =>
8334 Rewrite (N, New_Occurrence_Of (
8335 Boolean_Literals (Is_Definite_Subtype (P_Entity)), Loc));
8336 Analyze_And_Resolve (N, Standard_Boolean);
8338 -----------
8339 -- Delta --
8340 -----------
8342 when Attribute_Delta =>
8343 Fold_Ureal (N, Delta_Value (P_Type), True);
8345 ------------
8346 -- Denorm --
8347 ------------
8349 when Attribute_Denorm =>
8350 Fold_Uint
8351 (N, UI_From_Int (Boolean'Pos (Has_Denormals (P_Type))), Static);
8353 ---------------------
8354 -- Descriptor_Size --
8355 ---------------------
8357 when Attribute_Descriptor_Size =>
8358 null;
8360 ------------
8361 -- Digits --
8362 ------------
8364 when Attribute_Digits =>
8365 Fold_Uint (N, Digits_Value (P_Type), Static);
8367 ----------
8368 -- Emax --
8369 ----------
8371 when Attribute_Emax =>
8373 -- Ada 83 attribute is defined as (RM83 3.5.8)
8375 -- T'Emax = 4 * T'Mantissa
8377 Fold_Uint (N, 4 * Mantissa, Static);
8379 --------------
8380 -- Enum_Rep --
8381 --------------
8383 when Attribute_Enum_Rep => Enum_Rep : declare
8384 Val : Node_Id;
8386 begin
8387 -- The attribute appears in the form:
8389 -- Enum_Typ'Enum_Rep (Const)
8390 -- Enum_Typ'Enum_Rep (Enum_Lit)
8392 if Present (E1) then
8393 Val := E1;
8395 -- Otherwise the prefix denotes a constant or enumeration literal:
8397 -- Const'Enum_Rep
8398 -- Enum_Lit'Enum_Rep
8400 else
8401 Val := P;
8402 end if;
8404 -- For an enumeration type with a non-standard representation use
8405 -- the Enumeration_Rep field of the proper constant. Note that this
8406 -- will not work for types Character/Wide_[Wide-]Character, since no
8407 -- real entities are created for the enumeration literals, but that
8408 -- does not matter since these two types do not have non-standard
8409 -- representations anyway.
8411 if Is_Enumeration_Type (P_Type)
8412 and then Has_Non_Standard_Rep (P_Type)
8413 then
8414 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (Val)), Static);
8416 -- For enumeration types with standard representations and all other
8417 -- cases (i.e. all integer and modular types), Enum_Rep is equivalent
8418 -- to Pos.
8420 else
8421 Fold_Uint (N, Expr_Value (Val), Static);
8422 end if;
8423 end Enum_Rep;
8425 --------------
8426 -- Enum_Val --
8427 --------------
8429 when Attribute_Enum_Val => Enum_Val : declare
8430 Lit : Node_Id;
8432 begin
8433 -- We have something like Enum_Type'Enum_Val (23), so search for a
8434 -- corresponding value in the list of Enum_Rep values for the type.
8436 Lit := First_Literal (P_Base_Type);
8437 loop
8438 if Enumeration_Rep (Lit) = Expr_Value (E1) then
8439 Fold_Uint (N, Enumeration_Pos (Lit), Static);
8440 exit;
8441 end if;
8443 Next_Literal (Lit);
8445 if No (Lit) then
8446 Apply_Compile_Time_Constraint_Error
8447 (N, "no representation value matches",
8448 CE_Range_Check_Failed,
8449 Warn => not Static);
8450 exit;
8451 end if;
8452 end loop;
8453 end Enum_Val;
8455 -------------
8456 -- Epsilon --
8457 -------------
8459 when Attribute_Epsilon =>
8461 -- Ada 83 attribute is defined as (RM83 3.5.8)
8463 -- T'Epsilon = 2.0**(1 - T'Mantissa)
8465 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
8467 --------------
8468 -- Exponent --
8469 --------------
8471 when Attribute_Exponent =>
8472 Fold_Uint (N,
8473 Eval_Fat.Exponent (P_Base_Type, Expr_Value_R (E1)), Static);
8475 -----------------------
8476 -- Finalization_Size --
8477 -----------------------
8479 when Attribute_Finalization_Size =>
8480 null;
8482 -----------
8483 -- First --
8484 -----------
8486 when Attribute_First =>
8487 Set_Bounds;
8489 if Compile_Time_Known_Value (Lo_Bound) then
8490 if Is_Real_Type (P_Type) then
8491 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
8492 else
8493 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
8494 end if;
8496 else
8497 Check_Concurrent_Discriminant (Lo_Bound);
8498 end if;
8500 -----------------
8501 -- First_Valid --
8502 -----------------
8504 when Attribute_First_Valid =>
8505 if Has_Predicates (P_Type)
8506 and then Has_Static_Predicate (P_Type)
8507 then
8508 declare
8509 FirstN : constant Node_Id :=
8510 First (Static_Discrete_Predicate (P_Type));
8511 begin
8512 if Nkind (FirstN) = N_Range then
8513 Fold_Uint (N, Expr_Value (Low_Bound (FirstN)), Static);
8514 else
8515 Fold_Uint (N, Expr_Value (FirstN), Static);
8516 end if;
8517 end;
8519 else
8520 Set_Bounds;
8521 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
8522 end if;
8524 -----------------
8525 -- Fixed_Value --
8526 -----------------
8528 when Attribute_Fixed_Value =>
8529 null;
8531 -----------
8532 -- Floor --
8533 -----------
8535 when Attribute_Floor =>
8536 Fold_Ureal
8537 (N, Eval_Fat.Floor (P_Base_Type, Expr_Value_R (E1)), Static);
8539 ----------
8540 -- Fore --
8541 ----------
8543 when Attribute_Fore =>
8544 if Compile_Time_Known_Bounds (P_Type) then
8545 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
8546 end if;
8548 --------------
8549 -- Fraction --
8550 --------------
8552 when Attribute_Fraction =>
8553 Fold_Ureal
8554 (N, Eval_Fat.Fraction (P_Base_Type, Expr_Value_R (E1)), Static);
8556 -----------------------
8557 -- Has_Access_Values --
8558 -----------------------
8560 when Attribute_Has_Access_Values =>
8561 Rewrite (N, New_Occurrence_Of
8562 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
8563 Analyze_And_Resolve (N, Standard_Boolean);
8565 -----------------------
8566 -- Has_Discriminants --
8567 -----------------------
8569 when Attribute_Has_Discriminants =>
8570 Rewrite (N, New_Occurrence_Of (
8571 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
8572 Analyze_And_Resolve (N, Standard_Boolean);
8574 ----------------------
8575 -- Has_Same_Storage --
8576 ----------------------
8578 when Attribute_Has_Same_Storage =>
8579 null;
8581 -----------------------
8582 -- Has_Tagged_Values --
8583 -----------------------
8585 when Attribute_Has_Tagged_Values =>
8586 Rewrite (N, New_Occurrence_Of
8587 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
8588 Analyze_And_Resolve (N, Standard_Boolean);
8590 --------------
8591 -- Identity --
8592 --------------
8594 when Attribute_Identity =>
8595 null;
8597 -----------
8598 -- Image --
8599 -----------
8601 -- Image is a scalar attribute, but is never static, because it is
8602 -- not a static function (having a non-scalar argument (RM 4.9(22))
8603 -- However, we can constant-fold the image of an enumeration literal
8604 -- if names are available.
8606 when Attribute_Image =>
8607 if Is_Entity_Name (E1)
8608 and then Ekind (Entity (E1)) = E_Enumeration_Literal
8609 and then not Discard_Names (First_Subtype (Etype (E1)))
8610 and then not Global_Discard_Names
8611 then
8612 declare
8613 Lit : constant Entity_Id := Entity (E1);
8614 Str : String_Id;
8615 begin
8616 Start_String;
8617 Get_Unqualified_Decoded_Name_String (Chars (Lit));
8618 Set_Casing (All_Upper_Case);
8619 Store_String_Chars (Name_Buffer (1 .. Name_Len));
8620 Str := End_String;
8621 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
8622 Analyze_And_Resolve (N, Standard_String);
8623 Set_Is_Static_Expression (N, False);
8624 end;
8625 end if;
8627 -------------------
8628 -- Integer_Value --
8629 -------------------
8631 -- We never try to fold Integer_Value (though perhaps we could???)
8633 when Attribute_Integer_Value =>
8634 null;
8636 -------------------
8637 -- Invalid_Value --
8638 -------------------
8640 -- Invalid_Value is a scalar attribute that is never static, because
8641 -- the value is by design out of range.
8643 when Attribute_Invalid_Value =>
8644 null;
8646 -----------
8647 -- Large --
8648 -----------
8650 when Attribute_Large =>
8652 -- For fixed-point, we use the identity:
8654 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
8656 if Is_Fixed_Point_Type (P_Type) then
8657 Rewrite (N,
8658 Make_Op_Multiply (Loc,
8659 Left_Opnd =>
8660 Make_Op_Subtract (Loc,
8661 Left_Opnd =>
8662 Make_Op_Expon (Loc,
8663 Left_Opnd =>
8664 Make_Real_Literal (Loc, Ureal_2),
8665 Right_Opnd =>
8666 Make_Attribute_Reference (Loc,
8667 Prefix => P,
8668 Attribute_Name => Name_Mantissa)),
8669 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
8671 Right_Opnd =>
8672 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
8674 Analyze_And_Resolve (N, C_Type);
8676 -- Floating-point (Ada 83 compatibility)
8678 else
8679 -- Ada 83 attribute is defined as (RM83 3.5.8)
8681 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
8683 -- where
8685 -- T'Emax = 4 * T'Mantissa
8687 Fold_Ureal
8689 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
8690 True);
8691 end if;
8693 ---------------
8694 -- Lock_Free --
8695 ---------------
8697 when Attribute_Lock_Free => Lock_Free : declare
8698 V : constant Entity_Id := Boolean_Literals (Uses_Lock_Free (P_Type));
8700 begin
8701 Rewrite (N, New_Occurrence_Of (V, Loc));
8703 -- Analyze and resolve as boolean. Note that this attribute is a
8704 -- static attribute in GNAT.
8706 Analyze_And_Resolve (N, Standard_Boolean);
8707 Static := True;
8708 Set_Is_Static_Expression (N, True);
8709 end Lock_Free;
8711 ----------
8712 -- Last --
8713 ----------
8715 when Attribute_Last =>
8716 Set_Bounds;
8718 if Compile_Time_Known_Value (Hi_Bound) then
8719 if Is_Real_Type (P_Type) then
8720 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
8721 else
8722 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
8723 end if;
8725 else
8726 Check_Concurrent_Discriminant (Hi_Bound);
8727 end if;
8729 ----------------
8730 -- Last_Valid --
8731 ----------------
8733 when Attribute_Last_Valid =>
8734 if Has_Predicates (P_Type)
8735 and then Has_Static_Predicate (P_Type)
8736 then
8737 declare
8738 LastN : constant Node_Id :=
8739 Last (Static_Discrete_Predicate (P_Type));
8740 begin
8741 if Nkind (LastN) = N_Range then
8742 Fold_Uint (N, Expr_Value (High_Bound (LastN)), Static);
8743 else
8744 Fold_Uint (N, Expr_Value (LastN), Static);
8745 end if;
8746 end;
8748 else
8749 Set_Bounds;
8750 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
8751 end if;
8753 ------------------
8754 -- Leading_Part --
8755 ------------------
8757 when Attribute_Leading_Part =>
8758 Fold_Ureal
8760 Eval_Fat.Leading_Part
8761 (P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)),
8762 Static);
8764 ------------
8765 -- Length --
8766 ------------
8768 when Attribute_Length => Length : declare
8769 Ind : Node_Id;
8771 begin
8772 -- If any index type is a formal type, or derived from one, the
8773 -- bounds are not static. Treating them as static can produce
8774 -- spurious warnings or improper constant folding.
8776 Ind := First_Index (P_Type);
8777 while Present (Ind) loop
8778 if Is_Generic_Type (Root_Type (Etype (Ind))) then
8779 return;
8780 end if;
8782 Next_Index (Ind);
8783 end loop;
8785 Set_Bounds;
8787 -- For two compile time values, we can compute length
8789 if Compile_Time_Known_Value (Lo_Bound)
8790 and then Compile_Time_Known_Value (Hi_Bound)
8791 then
8792 Fold_Uint (N,
8793 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
8794 Static);
8795 end if;
8797 -- One more case is where Hi_Bound and Lo_Bound are compile-time
8798 -- comparable, and we can figure out the difference between them.
8800 declare
8801 Diff : aliased Uint;
8803 begin
8804 case
8805 Compile_Time_Compare
8806 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
8808 when EQ =>
8809 Fold_Uint (N, Uint_1, Static);
8811 when GT =>
8812 Fold_Uint (N, Uint_0, Static);
8814 when LT =>
8815 if Diff /= No_Uint then
8816 Fold_Uint (N, Diff + 1, Static);
8817 end if;
8819 when others =>
8820 null;
8821 end case;
8822 end;
8823 end Length;
8825 ----------------
8826 -- Loop_Entry --
8827 ----------------
8829 -- Loop_Entry acts as an alias of a constant initialized to the prefix
8830 -- of the said attribute at the point of entry into the related loop. As
8831 -- such, the attribute reference does not need to be evaluated because
8832 -- the prefix is the one that is evaluted.
8834 when Attribute_Loop_Entry =>
8835 null;
8837 -------------
8838 -- Machine --
8839 -------------
8841 when Attribute_Machine =>
8842 Fold_Ureal
8844 Eval_Fat.Machine
8845 (P_Base_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
8846 Static);
8848 ------------------
8849 -- Machine_Emax --
8850 ------------------
8852 when Attribute_Machine_Emax =>
8853 Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
8855 ------------------
8856 -- Machine_Emin --
8857 ------------------
8859 when Attribute_Machine_Emin =>
8860 Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
8862 ----------------------
8863 -- Machine_Mantissa --
8864 ----------------------
8866 when Attribute_Machine_Mantissa =>
8867 Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
8869 -----------------------
8870 -- Machine_Overflows --
8871 -----------------------
8873 when Attribute_Machine_Overflows =>
8875 -- Always true for fixed-point
8877 if Is_Fixed_Point_Type (P_Type) then
8878 Fold_Uint (N, True_Value, Static);
8880 -- Floating point case
8882 else
8883 Fold_Uint (N,
8884 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
8885 Static);
8886 end if;
8888 -------------------
8889 -- Machine_Radix --
8890 -------------------
8892 when Attribute_Machine_Radix =>
8893 if Is_Fixed_Point_Type (P_Type) then
8894 if Is_Decimal_Fixed_Point_Type (P_Type)
8895 and then Machine_Radix_10 (P_Type)
8896 then
8897 Fold_Uint (N, Uint_10, Static);
8898 else
8899 Fold_Uint (N, Uint_2, Static);
8900 end if;
8902 -- All floating-point type always have radix 2
8904 else
8905 Fold_Uint (N, Uint_2, Static);
8906 end if;
8908 ----------------------
8909 -- Machine_Rounding --
8910 ----------------------
8912 -- Note: for the folding case, it is fine to treat Machine_Rounding
8913 -- exactly the same way as Rounding, since this is one of the allowed
8914 -- behaviors, and performance is not an issue here. It might be a bit
8915 -- better to give the same result as it would give at run time, even
8916 -- though the non-determinism is certainly permitted.
8918 when Attribute_Machine_Rounding =>
8919 Fold_Ureal
8920 (N, Eval_Fat.Rounding (P_Base_Type, Expr_Value_R (E1)), Static);
8922 --------------------
8923 -- Machine_Rounds --
8924 --------------------
8926 when Attribute_Machine_Rounds =>
8928 -- Always False for fixed-point
8930 if Is_Fixed_Point_Type (P_Type) then
8931 Fold_Uint (N, False_Value, Static);
8933 -- Else yield proper floating-point result
8935 else
8936 Fold_Uint
8937 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)),
8938 Static);
8939 end if;
8941 ------------------
8942 -- Machine_Size --
8943 ------------------
8945 -- Note: Machine_Size is identical to Object_Size
8947 when Attribute_Machine_Size => Machine_Size : declare
8948 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
8950 begin
8951 if Known_Esize (P_TypeA) then
8952 Fold_Uint (N, Esize (P_TypeA), Static);
8953 end if;
8954 end Machine_Size;
8956 --------------
8957 -- Mantissa --
8958 --------------
8960 when Attribute_Mantissa =>
8962 -- Fixed-point mantissa
8964 if Is_Fixed_Point_Type (P_Type) then
8966 -- Compile time foldable case
8968 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
8969 and then
8970 Compile_Time_Known_Value (Type_High_Bound (P_Type))
8971 then
8972 -- The calculation of the obsolete Ada 83 attribute Mantissa
8973 -- is annoying, because of AI00143, quoted here:
8975 -- !question 84-01-10
8977 -- Consider the model numbers for F:
8979 -- type F is delta 1.0 range -7.0 .. 8.0;
8981 -- The wording requires that F'MANTISSA be the SMALLEST
8982 -- integer number for which each bound of the specified
8983 -- range is either a model number or lies at most small
8984 -- distant from a model number. This means F'MANTISSA
8985 -- is required to be 3 since the range -7.0 .. 7.0 fits
8986 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
8987 -- number, namely, 7. Is this analysis correct? Note that
8988 -- this implies the upper bound of the range is not
8989 -- represented as a model number.
8991 -- !response 84-03-17
8993 -- The analysis is correct. The upper and lower bounds for
8994 -- a fixed point type can lie outside the range of model
8995 -- numbers.
8997 declare
8998 Siz : Uint;
8999 LBound : Ureal;
9000 UBound : Ureal;
9001 Bound : Ureal;
9002 Max_Man : Uint;
9004 begin
9005 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
9006 UBound := Expr_Value_R (Type_High_Bound (P_Type));
9007 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
9008 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
9010 -- If the Bound is exactly a model number, i.e. a multiple
9011 -- of Small, then we back it off by one to get the integer
9012 -- value that must be representable.
9014 if Small_Value (P_Type) * Max_Man = Bound then
9015 Max_Man := Max_Man - 1;
9016 end if;
9018 -- Now find corresponding size = Mantissa value
9020 Siz := Uint_0;
9021 while 2 ** Siz < Max_Man loop
9022 Siz := Siz + 1;
9023 end loop;
9025 Fold_Uint (N, Siz, Static);
9026 end;
9028 else
9029 -- The case of dynamic bounds cannot be evaluated at compile
9030 -- time. Instead we use a runtime routine (see Exp_Attr).
9032 null;
9033 end if;
9035 -- Floating-point Mantissa
9037 else
9038 Fold_Uint (N, Mantissa, Static);
9039 end if;
9041 ---------
9042 -- Max --
9043 ---------
9045 when Attribute_Max =>
9046 if Is_Real_Type (P_Type) then
9047 Fold_Ureal
9048 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
9049 else
9050 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
9051 end if;
9053 ----------------------------------
9054 -- Max_Alignment_For_Allocation --
9055 ----------------------------------
9057 -- Max_Alignment_For_Allocation is usually the Alignment. However,
9058 -- arrays are allocated with dope, so we need to take into account both
9059 -- the alignment of the array, which comes from the component alignment,
9060 -- and the alignment of the dope. Also, if the alignment is unknown, we
9061 -- use the max (it's OK to be pessimistic).
9063 when Attribute_Max_Alignment_For_Allocation => Max_Align : declare
9064 A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
9065 begin
9066 if Known_Alignment (P_Type)
9067 and then (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
9068 then
9069 A := Alignment (P_Type);
9070 end if;
9072 Fold_Uint (N, A, Static);
9073 end Max_Align;
9075 ----------------------------------
9076 -- Max_Size_In_Storage_Elements --
9077 ----------------------------------
9079 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
9080 -- Storage_Unit boundary. We can fold any cases for which the size
9081 -- is known by the front end.
9083 when Attribute_Max_Size_In_Storage_Elements =>
9084 if Known_Esize (P_Type) then
9085 Fold_Uint (N,
9086 (Esize (P_Type) + System_Storage_Unit - 1) /
9087 System_Storage_Unit,
9088 Static);
9089 end if;
9091 --------------------
9092 -- Mechanism_Code --
9093 --------------------
9095 when Attribute_Mechanism_Code => Mechanism_Code : declare
9096 Formal : Entity_Id;
9097 Mech : Mechanism_Type;
9098 Val : Int;
9100 begin
9101 if No (E1) then
9102 Mech := Mechanism (P_Entity);
9104 else
9105 Val := UI_To_Int (Expr_Value (E1));
9107 Formal := First_Formal (P_Entity);
9108 for J in 1 .. Val - 1 loop
9109 Next_Formal (Formal);
9110 end loop;
9112 Mech := Mechanism (Formal);
9113 end if;
9115 if Mech < 0 then
9116 Fold_Uint (N, UI_From_Int (Int (-Mech)), Static);
9117 end if;
9118 end Mechanism_Code;
9120 ---------
9121 -- Min --
9122 ---------
9124 when Attribute_Min =>
9125 if Is_Real_Type (P_Type) then
9126 Fold_Ureal
9127 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
9128 else
9129 Fold_Uint
9130 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
9131 end if;
9133 ---------
9134 -- Mod --
9135 ---------
9137 when Attribute_Mod =>
9138 Fold_Uint
9139 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
9141 -----------
9142 -- Model --
9143 -----------
9145 when Attribute_Model =>
9146 Fold_Ureal
9147 (N, Eval_Fat.Model (P_Base_Type, Expr_Value_R (E1)), Static);
9149 ----------------
9150 -- Model_Emin --
9151 ----------------
9153 when Attribute_Model_Emin =>
9154 Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
9156 -------------------
9157 -- Model_Epsilon --
9158 -------------------
9160 when Attribute_Model_Epsilon =>
9161 Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
9163 --------------------
9164 -- Model_Mantissa --
9165 --------------------
9167 when Attribute_Model_Mantissa =>
9168 Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
9170 -----------------
9171 -- Model_Small --
9172 -----------------
9174 when Attribute_Model_Small =>
9175 Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
9177 -------------
9178 -- Modulus --
9179 -------------
9181 when Attribute_Modulus =>
9182 Fold_Uint (N, Modulus (P_Type), Static);
9184 --------------------
9185 -- Null_Parameter --
9186 --------------------
9188 -- Cannot fold, we know the value sort of, but the whole point is
9189 -- that there is no way to talk about this imaginary value except
9190 -- by using the attribute, so we leave it the way it is.
9192 when Attribute_Null_Parameter =>
9193 null;
9195 -----------------
9196 -- Object_Size --
9197 -----------------
9199 -- The Object_Size attribute for a type returns the Esize of the
9200 -- type and can be folded if this value is known.
9202 when Attribute_Object_Size => Object_Size : declare
9203 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
9205 begin
9206 if Known_Esize (P_TypeA) then
9207 Fold_Uint (N, Esize (P_TypeA), Static);
9208 end if;
9209 end Object_Size;
9211 ----------------------
9212 -- Overlaps_Storage --
9213 ----------------------
9215 when Attribute_Overlaps_Storage =>
9216 null;
9218 -------------------------
9219 -- Passed_By_Reference --
9220 -------------------------
9222 -- Scalar types are never passed by reference
9224 when Attribute_Passed_By_Reference =>
9225 Fold_Uint (N, False_Value, Static);
9227 ---------
9228 -- Pos --
9229 ---------
9231 when Attribute_Pos =>
9232 Fold_Uint (N, Expr_Value (E1), Static);
9234 ----------
9235 -- Pred --
9236 ----------
9238 when Attribute_Pred =>
9240 -- Floating-point case
9242 if Is_Floating_Point_Type (P_Type) then
9243 Fold_Ureal
9244 (N, Eval_Fat.Pred (P_Base_Type, Expr_Value_R (E1)), Static);
9246 -- Fixed-point case
9248 elsif Is_Fixed_Point_Type (P_Type) then
9249 Fold_Ureal
9250 (N, Expr_Value_R (E1) - Small_Value (P_Type), True);
9252 -- Modular integer case (wraps)
9254 elsif Is_Modular_Integer_Type (P_Type) then
9255 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
9257 -- Other scalar cases
9259 else
9260 pragma Assert (Is_Scalar_Type (P_Type));
9262 if Is_Enumeration_Type (P_Type)
9263 and then Expr_Value (E1) =
9264 Expr_Value (Type_Low_Bound (P_Base_Type))
9265 then
9266 Apply_Compile_Time_Constraint_Error
9267 (N, "Pred of `&''First`",
9268 CE_Overflow_Check_Failed,
9269 Ent => P_Base_Type,
9270 Warn => not Static);
9272 Check_Expressions;
9273 return;
9274 end if;
9276 Fold_Uint (N, Expr_Value (E1) - 1, Static);
9277 end if;
9279 -----------
9280 -- Range --
9281 -----------
9283 -- No processing required, because by this stage, Range has been
9284 -- replaced by First .. Last, so this branch can never be taken.
9286 when Attribute_Range =>
9287 raise Program_Error;
9289 ------------------
9290 -- Range_Length --
9291 ------------------
9293 when Attribute_Range_Length => Range_Length : declare
9294 Diff : aliased Uint;
9296 begin
9297 Set_Bounds;
9299 -- Can fold if both bounds are compile time known
9301 if Compile_Time_Known_Value (Hi_Bound)
9302 and then Compile_Time_Known_Value (Lo_Bound)
9303 then
9304 Fold_Uint (N,
9305 UI_Max
9306 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
9307 Static);
9308 end if;
9310 -- One more case is where Hi_Bound and Lo_Bound are compile-time
9311 -- comparable, and we can figure out the difference between them.
9313 case Compile_Time_Compare
9314 (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
9316 when EQ =>
9317 Fold_Uint (N, Uint_1, Static);
9319 when GT =>
9320 Fold_Uint (N, Uint_0, Static);
9322 when LT =>
9323 if Diff /= No_Uint then
9324 Fold_Uint (N, Diff + 1, Static);
9325 end if;
9327 when others =>
9328 null;
9329 end case;
9330 end Range_Length;
9332 ---------
9333 -- Ref --
9334 ---------
9336 when Attribute_Ref =>
9337 Fold_Uint (N, Expr_Value (E1), Static);
9339 ---------------
9340 -- Remainder --
9341 ---------------
9343 when Attribute_Remainder => Remainder : declare
9344 X : constant Ureal := Expr_Value_R (E1);
9345 Y : constant Ureal := Expr_Value_R (E2);
9347 begin
9348 if UR_Is_Zero (Y) then
9349 Apply_Compile_Time_Constraint_Error
9350 (N, "division by zero in Remainder",
9351 CE_Overflow_Check_Failed,
9352 Warn => not Static);
9354 Check_Expressions;
9355 return;
9356 end if;
9358 Fold_Ureal (N, Eval_Fat.Remainder (P_Base_Type, X, Y), Static);
9359 end Remainder;
9361 -----------------
9362 -- Restriction --
9363 -----------------
9365 when Attribute_Restriction_Set =>
9366 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
9367 Set_Is_Static_Expression (N);
9369 -----------
9370 -- Round --
9371 -----------
9373 when Attribute_Round => Round : declare
9374 Sr : Ureal;
9375 Si : Uint;
9377 begin
9378 -- First we get the (exact result) in units of small
9380 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
9382 -- Now round that exactly to an integer
9384 Si := UR_To_Uint (Sr);
9386 -- Finally the result is obtained by converting back to real
9388 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
9389 end Round;
9391 --------------
9392 -- Rounding --
9393 --------------
9395 when Attribute_Rounding =>
9396 Fold_Ureal
9397 (N, Eval_Fat.Rounding (P_Base_Type, Expr_Value_R (E1)), Static);
9399 ---------------
9400 -- Safe_Emax --
9401 ---------------
9403 when Attribute_Safe_Emax =>
9404 Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
9406 ----------------
9407 -- Safe_First --
9408 ----------------
9410 when Attribute_Safe_First =>
9411 Fold_Ureal (N, Safe_First_Value (P_Type), Static);
9413 ----------------
9414 -- Safe_Large --
9415 ----------------
9417 when Attribute_Safe_Large =>
9418 if Is_Fixed_Point_Type (P_Type) then
9419 Fold_Ureal
9420 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
9421 else
9422 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
9423 end if;
9425 ---------------
9426 -- Safe_Last --
9427 ---------------
9429 when Attribute_Safe_Last =>
9430 Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
9432 ----------------
9433 -- Safe_Small --
9434 ----------------
9436 when Attribute_Safe_Small =>
9438 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
9439 -- for fixed-point, since is the same as Small, but we implement
9440 -- it for backwards compatibility.
9442 if Is_Fixed_Point_Type (P_Type) then
9443 Fold_Ureal (N, Small_Value (P_Type), Static);
9445 -- Ada 83 Safe_Small for floating-point cases
9447 else
9448 Fold_Ureal (N, Model_Small_Value (P_Type), Static);
9449 end if;
9451 -----------
9452 -- Scale --
9453 -----------
9455 when Attribute_Scale =>
9456 Fold_Uint (N, Scale_Value (P_Type), Static);
9458 -------------
9459 -- Scaling --
9460 -------------
9462 when Attribute_Scaling =>
9463 Fold_Ureal
9465 Eval_Fat.Scaling
9466 (P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)),
9467 Static);
9469 ------------------
9470 -- Signed_Zeros --
9471 ------------------
9473 when Attribute_Signed_Zeros =>
9474 Fold_Uint
9475 (N, UI_From_Int (Boolean'Pos (Has_Signed_Zeros (P_Type))), Static);
9477 ----------
9478 -- Size --
9479 ----------
9481 -- Size attribute returns the RM size. All scalar types can be folded,
9482 -- as well as any types for which the size is known by the front end,
9483 -- including any type for which a size attribute is specified. This is
9484 -- one of the places where it is annoying that a size of zero means two
9485 -- things (zero size for scalars, unspecified size for non-scalars).
9487 when Attribute_Size
9488 | Attribute_VADS_Size
9490 Size : declare
9491 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
9493 begin
9494 if Is_Scalar_Type (P_TypeA)
9495 or else RM_Size (P_TypeA) /= Uint_0
9496 then
9497 -- VADS_Size case
9499 if Id = Attribute_VADS_Size or else Use_VADS_Size then
9500 declare
9501 S : constant Node_Id := Size_Clause (P_TypeA);
9503 begin
9504 -- If a size clause applies, then use the size from it.
9505 -- This is one of the rare cases where we can use the
9506 -- Size_Clause field for a subtype when Has_Size_Clause
9507 -- is False. Consider:
9509 -- type x is range 1 .. 64;
9510 -- for x'size use 12;
9511 -- subtype y is x range 0 .. 3;
9513 -- Here y has a size clause inherited from x, but
9514 -- normally it does not apply, and y'size is 2. However,
9515 -- y'VADS_Size is indeed 12 and not 2.
9517 if Present (S)
9518 and then Is_OK_Static_Expression (Expression (S))
9519 then
9520 Fold_Uint (N, Expr_Value (Expression (S)), Static);
9522 -- If no size is specified, then we simply use the object
9523 -- size in the VADS_Size case (e.g. Natural'Size is equal
9524 -- to Integer'Size, not one less).
9526 else
9527 Fold_Uint (N, Esize (P_TypeA), Static);
9528 end if;
9529 end;
9531 -- Normal case (Size) in which case we want the RM_Size
9533 else
9534 Fold_Uint (N, RM_Size (P_TypeA), Static);
9535 end if;
9536 end if;
9537 end Size;
9539 -----------
9540 -- Small --
9541 -----------
9543 when Attribute_Small =>
9545 -- The floating-point case is present only for Ada 83 compatibility.
9546 -- Note that strictly this is an illegal addition, since we are
9547 -- extending an Ada 95 defined attribute, but we anticipate an
9548 -- ARG ruling that will permit this.
9550 if Is_Floating_Point_Type (P_Type) then
9552 -- Ada 83 attribute is defined as (RM83 3.5.8)
9554 -- T'Small = 2.0**(-T'Emax - 1)
9556 -- where
9558 -- T'Emax = 4 * T'Mantissa
9560 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
9562 -- Normal Ada 95 fixed-point case
9564 else
9565 Fold_Ureal (N, Small_Value (P_Type), True);
9566 end if;
9568 -----------------
9569 -- Stream_Size --
9570 -----------------
9572 when Attribute_Stream_Size =>
9573 null;
9575 ----------
9576 -- Succ --
9577 ----------
9579 when Attribute_Succ =>
9580 -- Floating-point case
9582 if Is_Floating_Point_Type (P_Type) then
9583 Fold_Ureal
9584 (N, Eval_Fat.Succ (P_Base_Type, Expr_Value_R (E1)), Static);
9586 -- Fixed-point case
9588 elsif Is_Fixed_Point_Type (P_Type) then
9589 Fold_Ureal (N, Expr_Value_R (E1) + Small_Value (P_Type), Static);
9591 -- Modular integer case (wraps)
9593 elsif Is_Modular_Integer_Type (P_Type) then
9594 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
9596 -- Other scalar cases
9598 else
9599 pragma Assert (Is_Scalar_Type (P_Type));
9601 if Is_Enumeration_Type (P_Type)
9602 and then Expr_Value (E1) =
9603 Expr_Value (Type_High_Bound (P_Base_Type))
9604 then
9605 Apply_Compile_Time_Constraint_Error
9606 (N, "Succ of `&''Last`",
9607 CE_Overflow_Check_Failed,
9608 Ent => P_Base_Type,
9609 Warn => not Static);
9611 Check_Expressions;
9612 return;
9613 else
9614 Fold_Uint (N, Expr_Value (E1) + 1, Static);
9615 end if;
9616 end if;
9618 ----------------
9619 -- Truncation --
9620 ----------------
9622 when Attribute_Truncation =>
9623 Fold_Ureal
9625 Eval_Fat.Truncation (P_Base_Type, Expr_Value_R (E1)),
9626 Static);
9628 ----------------
9629 -- Type_Class --
9630 ----------------
9632 when Attribute_Type_Class => Type_Class : declare
9633 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
9634 Id : RE_Id;
9636 begin
9637 if Is_Descendant_Of_Address (Typ) then
9638 Id := RE_Type_Class_Address;
9640 elsif Is_Enumeration_Type (Typ) then
9641 Id := RE_Type_Class_Enumeration;
9643 elsif Is_Integer_Type (Typ) then
9644 Id := RE_Type_Class_Integer;
9646 elsif Is_Fixed_Point_Type (Typ) then
9647 Id := RE_Type_Class_Fixed_Point;
9649 elsif Is_Floating_Point_Type (Typ) then
9650 Id := RE_Type_Class_Floating_Point;
9652 elsif Is_Array_Type (Typ) then
9653 Id := RE_Type_Class_Array;
9655 elsif Is_Record_Type (Typ) then
9656 Id := RE_Type_Class_Record;
9658 elsif Is_Access_Type (Typ) then
9659 Id := RE_Type_Class_Access;
9661 elsif Is_Task_Type (Typ) then
9662 Id := RE_Type_Class_Task;
9664 -- We treat protected types like task types. It would make more
9665 -- sense to have another enumeration value, but after all the
9666 -- whole point of this feature is to be exactly DEC compatible,
9667 -- and changing the type Type_Class would not meet this requirement.
9669 elsif Is_Protected_Type (Typ) then
9670 Id := RE_Type_Class_Task;
9672 -- Not clear if there are any other possibilities, but if there
9673 -- are, then we will treat them as the address case.
9675 else
9676 Id := RE_Type_Class_Address;
9677 end if;
9679 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
9680 end Type_Class;
9682 -----------------------
9683 -- Unbiased_Rounding --
9684 -----------------------
9686 when Attribute_Unbiased_Rounding =>
9687 Fold_Ureal
9689 Eval_Fat.Unbiased_Rounding (P_Base_Type, Expr_Value_R (E1)),
9690 Static);
9692 -------------------------
9693 -- Unconstrained_Array --
9694 -------------------------
9696 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
9697 Typ : constant Entity_Id := Underlying_Type (P_Type);
9699 begin
9700 Rewrite (N, New_Occurrence_Of (
9701 Boolean_Literals (
9702 Is_Array_Type (P_Type)
9703 and then not Is_Constrained (Typ)), Loc));
9705 -- Analyze and resolve as boolean, note that this attribute is
9706 -- a static attribute in GNAT.
9708 Analyze_And_Resolve (N, Standard_Boolean);
9709 Static := True;
9710 Set_Is_Static_Expression (N, True);
9711 end Unconstrained_Array;
9713 -- Attribute Update is never static
9715 when Attribute_Update =>
9716 return;
9718 ---------------
9719 -- VADS_Size --
9720 ---------------
9722 -- Processing is shared with Size
9724 ---------
9725 -- Val --
9726 ---------
9728 when Attribute_Val =>
9729 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
9730 or else
9731 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
9732 then
9733 Apply_Compile_Time_Constraint_Error
9734 (N, "Val expression out of range",
9735 CE_Range_Check_Failed,
9736 Warn => not Static);
9738 Check_Expressions;
9739 return;
9741 else
9742 Fold_Uint (N, Expr_Value (E1), Static);
9743 end if;
9745 ----------------
9746 -- Value_Size --
9747 ----------------
9749 -- The Value_Size attribute for a type returns the RM size of the type.
9750 -- This an always be folded for scalar types, and can also be folded for
9751 -- non-scalar types if the size is set. This is one of the places where
9752 -- it is annoying that a size of zero means two things!
9754 when Attribute_Value_Size => Value_Size : declare
9755 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
9757 begin
9758 if Is_Scalar_Type (P_TypeA) or else RM_Size (P_TypeA) /= Uint_0 then
9759 Fold_Uint (N, RM_Size (P_TypeA), Static);
9760 end if;
9761 end Value_Size;
9763 -------------
9764 -- Version --
9765 -------------
9767 -- Version can never be static
9769 when Attribute_Version =>
9770 null;
9772 ----------------
9773 -- Wide_Image --
9774 ----------------
9776 -- Wide_Image is a scalar attribute, but is never static, because it
9777 -- is not a static function (having a non-scalar argument (RM 4.9(22))
9779 when Attribute_Wide_Image =>
9780 null;
9782 ---------------------
9783 -- Wide_Wide_Image --
9784 ---------------------
9786 -- Wide_Wide_Image is a scalar attribute but is never static, because it
9787 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
9789 when Attribute_Wide_Wide_Image =>
9790 null;
9792 ---------------------
9793 -- Wide_Wide_Width --
9794 ---------------------
9796 -- Processing for Wide_Wide_Width is combined with Width
9798 ----------------
9799 -- Wide_Width --
9800 ----------------
9802 -- Processing for Wide_Width is combined with Width
9804 -----------
9805 -- Width --
9806 -----------
9808 -- This processing also handles the case of Wide_[Wide_]Width
9810 when Attribute_Width
9811 | Attribute_Wide_Width
9812 | Attribute_Wide_Wide_Width
9814 if Compile_Time_Known_Bounds (P_Type) then
9816 -- Floating-point types
9818 if Is_Floating_Point_Type (P_Type) then
9820 -- Width is zero for a null range (RM 3.5 (38))
9822 if Expr_Value_R (Type_High_Bound (P_Type)) <
9823 Expr_Value_R (Type_Low_Bound (P_Type))
9824 then
9825 Fold_Uint (N, Uint_0, Static);
9827 else
9828 -- For floating-point, we have +N.dddE+nnn where length
9829 -- of ddd is determined by type'Digits - 1, but is one
9830 -- if Digits is one (RM 3.5 (33)).
9832 -- nnn is set to 2 for Short_Float and Float (32 bit
9833 -- floats), and 3 for Long_Float and Long_Long_Float.
9834 -- For machines where Long_Long_Float is the IEEE
9835 -- extended precision type, the exponent takes 4 digits.
9837 declare
9838 Len : Int :=
9839 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
9841 begin
9842 if Esize (P_Type) <= 32 then
9843 Len := Len + 6;
9844 elsif Esize (P_Type) = 64 then
9845 Len := Len + 7;
9846 else
9847 Len := Len + 8;
9848 end if;
9850 Fold_Uint (N, UI_From_Int (Len), Static);
9851 end;
9852 end if;
9854 -- Fixed-point types
9856 elsif Is_Fixed_Point_Type (P_Type) then
9858 -- Width is zero for a null range (RM 3.5 (38))
9860 if Expr_Value (Type_High_Bound (P_Type)) <
9861 Expr_Value (Type_Low_Bound (P_Type))
9862 then
9863 Fold_Uint (N, Uint_0, Static);
9865 -- The non-null case depends on the specific real type
9867 else
9868 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
9870 Fold_Uint
9871 (N, UI_From_Int (Fore_Value + 1) + Aft_Value (P_Type),
9872 Static);
9873 end if;
9875 -- Discrete types
9877 else
9878 declare
9879 R : constant Entity_Id := Root_Type (P_Type);
9880 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
9881 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
9882 W : Nat;
9883 Wt : Nat;
9884 T : Uint;
9885 L : Node_Id;
9886 C : Character;
9888 begin
9889 -- Empty ranges
9891 if Lo > Hi then
9892 W := 0;
9894 -- Width for types derived from Standard.Character
9895 -- and Standard.Wide_[Wide_]Character.
9897 elsif Is_Standard_Character_Type (P_Type) then
9898 W := 0;
9900 -- Set W larger if needed
9902 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
9904 -- All wide characters look like Hex_hhhhhhhh
9906 if J > 255 then
9908 -- No need to compute this more than once
9910 exit;
9912 else
9913 C := Character'Val (J);
9915 -- Test for all cases where Character'Image
9916 -- yields an image that is longer than three
9917 -- characters. First the cases of Reserved_xxx
9918 -- names (length = 12).
9920 case C is
9921 when Reserved_128
9922 | Reserved_129
9923 | Reserved_132
9924 | Reserved_153
9926 Wt := 12;
9928 when BS
9929 | CR
9930 | EM
9931 | FF
9932 | FS
9933 | GS
9934 | HT
9935 | LF
9936 | MW
9937 | PM
9938 | RI
9939 | RS
9940 | SI
9941 | SO
9942 | ST
9943 | US
9944 | VT
9946 Wt := 2;
9948 when ACK
9949 | APC
9950 | BEL
9951 | BPH
9952 | CAN
9953 | CCH
9954 | CSI
9955 | DC1
9956 | DC2
9957 | DC3
9958 | DC4
9959 | DCS
9960 | DEL
9961 | DLE
9962 | ENQ
9963 | EOT
9964 | EPA
9965 | ESA
9966 | ESC
9967 | ETB
9968 | ETX
9969 | HTJ
9970 | HTS
9971 | NAK
9972 | NBH
9973 | NEL
9974 | NUL
9975 | OSC
9976 | PLD
9977 | PLU
9978 | PU1
9979 | PU2
9980 | SCI
9981 | SOH
9982 | SOS
9983 | SPA
9984 | SS2
9985 | SS3
9986 | SSA
9987 | STS
9988 | STX
9989 | SUB
9990 | SYN
9991 | VTS
9993 Wt := 3;
9995 when Space .. Tilde
9996 | No_Break_Space .. LC_Y_Diaeresis
9998 -- Special case of soft hyphen in Ada 2005
10000 if C = Character'Val (16#AD#)
10001 and then Ada_Version >= Ada_2005
10002 then
10003 Wt := 11;
10004 else
10005 Wt := 3;
10006 end if;
10007 end case;
10009 W := Int'Max (W, Wt);
10010 end if;
10011 end loop;
10013 -- Width for types derived from Standard.Boolean
10015 elsif R = Standard_Boolean then
10016 if Lo = 0 then
10017 W := 5; -- FALSE
10018 else
10019 W := 4; -- TRUE
10020 end if;
10022 -- Width for integer types
10024 elsif Is_Integer_Type (P_Type) then
10025 T := UI_Max (abs Lo, abs Hi);
10027 W := 2;
10028 while T >= 10 loop
10029 W := W + 1;
10030 T := T / 10;
10031 end loop;
10033 -- User declared enum type with discard names
10035 elsif Discard_Names (R) then
10037 -- If range is null, result is zero, that has already
10038 -- been dealt with, so what we need is the power of ten
10039 -- that accommodates the Pos of the largest value, which
10040 -- is the high bound of the range + one for the space.
10042 W := 1;
10043 T := Hi;
10044 while T /= 0 loop
10045 T := T / 10;
10046 W := W + 1;
10047 end loop;
10049 -- Only remaining possibility is user declared enum type
10050 -- with normal case of Discard_Names not active.
10052 else
10053 pragma Assert (Is_Enumeration_Type (P_Type));
10055 W := 0;
10056 L := First_Literal (P_Type);
10057 while Present (L) loop
10059 -- Only pay attention to in range characters
10061 if Lo <= Enumeration_Pos (L)
10062 and then Enumeration_Pos (L) <= Hi
10063 then
10064 -- For Width case, use decoded name
10066 if Id = Attribute_Width then
10067 Get_Decoded_Name_String (Chars (L));
10068 Wt := Nat (Name_Len);
10070 -- For Wide_[Wide_]Width, use encoded name, and
10071 -- then adjust for the encoding.
10073 else
10074 Get_Name_String (Chars (L));
10076 -- Character literals are always of length 3
10078 if Name_Buffer (1) = 'Q' then
10079 Wt := 3;
10081 -- Otherwise loop to adjust for upper/wide chars
10083 else
10084 Wt := Nat (Name_Len);
10086 for J in 1 .. Name_Len loop
10087 if Name_Buffer (J) = 'U' then
10088 Wt := Wt - 2;
10089 elsif Name_Buffer (J) = 'W' then
10090 Wt := Wt - 4;
10091 end if;
10092 end loop;
10093 end if;
10094 end if;
10096 W := Int'Max (W, Wt);
10097 end if;
10099 Next_Literal (L);
10100 end loop;
10101 end if;
10103 Fold_Uint (N, UI_From_Int (W), Static);
10104 end;
10105 end if;
10106 end if;
10108 -- The following attributes denote functions that cannot be folded
10110 when Attribute_From_Any
10111 | Attribute_To_Any
10112 | Attribute_TypeCode
10114 null;
10116 -- The following attributes can never be folded, and furthermore we
10117 -- should not even have entered the case statement for any of these.
10118 -- Note that in some cases, the values have already been folded as
10119 -- a result of the processing in Analyze_Attribute or earlier in
10120 -- this procedure.
10122 when Attribute_Abort_Signal
10123 | Attribute_Access
10124 | Attribute_Address
10125 | Attribute_Address_Size
10126 | Attribute_Asm_Input
10127 | Attribute_Asm_Output
10128 | Attribute_Base
10129 | Attribute_Bit_Order
10130 | Attribute_Bit_Position
10131 | Attribute_Callable
10132 | Attribute_Caller
10133 | Attribute_Class
10134 | Attribute_Code_Address
10135 | Attribute_Compiler_Version
10136 | Attribute_Count
10137 | Attribute_Default_Bit_Order
10138 | Attribute_Default_Scalar_Storage_Order
10139 | Attribute_Deref
10140 | Attribute_Elaborated
10141 | Attribute_Elab_Body
10142 | Attribute_Elab_Spec
10143 | Attribute_Elab_Subp_Body
10144 | Attribute_Enabled
10145 | Attribute_External_Tag
10146 | Attribute_Fast_Math
10147 | Attribute_First_Bit
10148 | Attribute_Img
10149 | Attribute_Input
10150 | Attribute_Last_Bit
10151 | Attribute_Library_Level
10152 | Attribute_Maximum_Alignment
10153 | Attribute_Old
10154 | Attribute_Output
10155 | Attribute_Partition_ID
10156 | Attribute_Pool_Address
10157 | Attribute_Position
10158 | Attribute_Priority
10159 | Attribute_Read
10160 | Attribute_Result
10161 | Attribute_Scalar_Storage_Order
10162 | Attribute_Simple_Storage_Pool
10163 | Attribute_Storage_Pool
10164 | Attribute_Storage_Size
10165 | Attribute_Storage_Unit
10166 | Attribute_Stub_Type
10167 | Attribute_System_Allocator_Alignment
10168 | Attribute_Tag
10169 | Attribute_Target_Name
10170 | Attribute_Terminated
10171 | Attribute_To_Address
10172 | Attribute_Type_Key
10173 | Attribute_Unchecked_Access
10174 | Attribute_Universal_Literal_String
10175 | Attribute_Unrestricted_Access
10176 | Attribute_Valid
10177 | Attribute_Valid_Scalars
10178 | Attribute_Value
10179 | Attribute_Wchar_T_Size
10180 | Attribute_Wide_Value
10181 | Attribute_Wide_Wide_Value
10182 | Attribute_Word_Size
10183 | Attribute_Write
10185 raise Program_Error;
10186 end case;
10188 -- At the end of the case, one more check. If we did a static evaluation
10189 -- so that the result is now a literal, then set Is_Static_Expression
10190 -- in the constant only if the prefix type is a static subtype. For
10191 -- non-static subtypes, the folding is still OK, but not static.
10193 -- An exception is the GNAT attribute Constrained_Array which is
10194 -- defined to be a static attribute in all cases.
10196 if Nkind_In (N, N_Integer_Literal,
10197 N_Real_Literal,
10198 N_Character_Literal,
10199 N_String_Literal)
10200 or else (Is_Entity_Name (N)
10201 and then Ekind (Entity (N)) = E_Enumeration_Literal)
10202 then
10203 Set_Is_Static_Expression (N, Static);
10205 -- If this is still an attribute reference, then it has not been folded
10206 -- and that means that its expressions are in a non-static context.
10208 elsif Nkind (N) = N_Attribute_Reference then
10209 Check_Expressions;
10211 -- Note: the else case not covered here are odd cases where the
10212 -- processing has transformed the attribute into something other
10213 -- than a constant. Nothing more to do in such cases.
10215 else
10216 null;
10217 end if;
10218 end Eval_Attribute;
10220 ------------------------------
10221 -- Is_Anonymous_Tagged_Base --
10222 ------------------------------
10224 function Is_Anonymous_Tagged_Base
10225 (Anon : Entity_Id;
10226 Typ : Entity_Id) return Boolean
10228 begin
10229 return
10230 Anon = Current_Scope
10231 and then Is_Itype (Anon)
10232 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
10233 end Is_Anonymous_Tagged_Base;
10235 --------------------------------
10236 -- Name_Implies_Lvalue_Prefix --
10237 --------------------------------
10239 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
10240 pragma Assert (Is_Attribute_Name (Nam));
10241 begin
10242 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
10243 end Name_Implies_Lvalue_Prefix;
10245 -----------------------
10246 -- Resolve_Attribute --
10247 -----------------------
10249 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
10250 Loc : constant Source_Ptr := Sloc (N);
10251 P : constant Node_Id := Prefix (N);
10252 Aname : constant Name_Id := Attribute_Name (N);
10253 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
10254 Btyp : constant Entity_Id := Base_Type (Typ);
10255 Des_Btyp : Entity_Id;
10256 Index : Interp_Index;
10257 It : Interp;
10258 Nom_Subt : Entity_Id;
10260 procedure Accessibility_Message;
10261 -- Error, or warning within an instance, if the static accessibility
10262 -- rules of 3.10.2 are violated.
10264 function Declared_Within_Generic_Unit
10265 (Entity : Entity_Id;
10266 Generic_Unit : Node_Id) return Boolean;
10267 -- Returns True if Declared_Entity is declared within the declarative
10268 -- region of Generic_Unit; otherwise returns False.
10270 ---------------------------
10271 -- Accessibility_Message --
10272 ---------------------------
10274 procedure Accessibility_Message is
10275 Indic : Node_Id := Parent (Parent (N));
10277 begin
10278 -- In an instance, this is a runtime check, but one we
10279 -- know will fail, so generate an appropriate warning.
10281 if In_Instance_Body then
10282 Error_Msg_Warn := SPARK_Mode /= On;
10283 Error_Msg_F
10284 ("non-local pointer cannot point to local object<<", P);
10285 Error_Msg_F ("\Program_Error [<<", P);
10286 Rewrite (N,
10287 Make_Raise_Program_Error (Loc,
10288 Reason => PE_Accessibility_Check_Failed));
10289 Set_Etype (N, Typ);
10290 return;
10292 else
10293 Error_Msg_F ("non-local pointer cannot point to local object", P);
10295 -- Check for case where we have a missing access definition
10297 if Is_Record_Type (Current_Scope)
10298 and then
10299 Nkind_In (Parent (N), N_Discriminant_Association,
10300 N_Index_Or_Discriminant_Constraint)
10301 then
10302 Indic := Parent (Parent (N));
10303 while Present (Indic)
10304 and then Nkind (Indic) /= N_Subtype_Indication
10305 loop
10306 Indic := Parent (Indic);
10307 end loop;
10309 if Present (Indic) then
10310 Error_Msg_NE
10311 ("\use an access definition for" &
10312 " the access discriminant of&",
10313 N, Entity (Subtype_Mark (Indic)));
10314 end if;
10315 end if;
10316 end if;
10317 end Accessibility_Message;
10319 ----------------------------------
10320 -- Declared_Within_Generic_Unit --
10321 ----------------------------------
10323 function Declared_Within_Generic_Unit
10324 (Entity : Entity_Id;
10325 Generic_Unit : Node_Id) return Boolean
10327 Generic_Encloser : Node_Id := Enclosing_Generic_Unit (Entity);
10329 begin
10330 while Present (Generic_Encloser) loop
10331 if Generic_Encloser = Generic_Unit then
10332 return True;
10333 end if;
10335 -- We have to step to the scope of the generic's entity, because
10336 -- otherwise we'll just get back the same generic.
10338 Generic_Encloser :=
10339 Enclosing_Generic_Unit
10340 (Scope (Defining_Entity (Generic_Encloser)));
10341 end loop;
10343 return False;
10344 end Declared_Within_Generic_Unit;
10346 -- Start of processing for Resolve_Attribute
10348 begin
10349 -- If error during analysis, no point in continuing, except for array
10350 -- types, where we get better recovery by using unconstrained indexes
10351 -- than nothing at all (see Check_Array_Type).
10353 if Error_Posted (N)
10354 and then Attr_Id /= Attribute_First
10355 and then Attr_Id /= Attribute_Last
10356 and then Attr_Id /= Attribute_Length
10357 and then Attr_Id /= Attribute_Range
10358 then
10359 return;
10360 end if;
10362 -- If attribute was universal type, reset to actual type
10364 if Etype (N) = Universal_Integer
10365 or else Etype (N) = Universal_Real
10366 then
10367 Set_Etype (N, Typ);
10368 end if;
10370 -- Remaining processing depends on attribute
10372 case Attr_Id is
10374 ------------
10375 -- Access --
10376 ------------
10378 -- For access attributes, if the prefix denotes an entity, it is
10379 -- interpreted as a name, never as a call. It may be overloaded,
10380 -- in which case resolution uses the profile of the context type.
10381 -- Otherwise prefix must be resolved.
10383 when Attribute_Access
10384 | Attribute_Unchecked_Access
10385 | Attribute_Unrestricted_Access
10387 -- Note possible modification if we have a variable
10389 if Is_Variable (P) then
10390 declare
10391 PN : constant Node_Id := Parent (N);
10392 Nm : Node_Id;
10394 Note : Boolean := True;
10395 -- Skip this for the case of Unrestricted_Access occuring in
10396 -- the context of a Valid check, since this otherwise leads
10397 -- to a missed warning (the Valid check does not really
10398 -- modify!) If this case, Note will be reset to False.
10400 -- Skip it as well if the type is an Acccess_To_Constant,
10401 -- given that no use of the value can modify the prefix.
10403 begin
10404 if Attr_Id = Attribute_Unrestricted_Access
10405 and then Nkind (PN) = N_Function_Call
10406 then
10407 Nm := Name (PN);
10409 if Nkind (Nm) = N_Expanded_Name
10410 and then Chars (Nm) = Name_Valid
10411 and then Nkind (Prefix (Nm)) = N_Identifier
10412 and then Chars (Prefix (Nm)) = Name_Attr_Long_Float
10413 then
10414 Note := False;
10415 end if;
10417 elsif Is_Access_Constant (Typ) then
10418 Note := False;
10419 end if;
10421 if Note then
10422 Note_Possible_Modification (P, Sure => False);
10423 end if;
10424 end;
10425 end if;
10427 -- The following comes from a query concerning improper use of
10428 -- universal_access in equality tests involving anonymous access
10429 -- types. Another good reason for 'Ref, but for now disable the
10430 -- test, which breaks several filed tests???
10432 if Ekind (Typ) = E_Anonymous_Access_Type
10433 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
10434 and then False
10435 then
10436 Error_Msg_N ("need unique type to resolve 'Access", N);
10437 Error_Msg_N ("\qualify attribute with some access type", N);
10438 end if;
10440 -- Case where prefix is an entity name
10442 if Is_Entity_Name (P) then
10444 -- Deal with case where prefix itself is overloaded
10446 if Is_Overloaded (P) then
10447 Get_First_Interp (P, Index, It);
10448 while Present (It.Nam) loop
10449 if Type_Conformant (Designated_Type (Typ), It.Nam) then
10450 Set_Entity (P, It.Nam);
10452 -- The prefix is definitely NOT overloaded anymore at
10453 -- this point, so we reset the Is_Overloaded flag to
10454 -- avoid any confusion when reanalyzing the node.
10456 Set_Is_Overloaded (P, False);
10457 Set_Is_Overloaded (N, False);
10458 Generate_Reference (Entity (P), P);
10459 exit;
10460 end if;
10462 Get_Next_Interp (Index, It);
10463 end loop;
10465 -- If Prefix is a subprogram name, this reference freezes,
10466 -- but not if within spec expression mode. The profile of
10467 -- the subprogram is not frozen at this point.
10469 if not In_Spec_Expression then
10470 Freeze_Before (N, Entity (P), Do_Freeze_Profile => False);
10471 end if;
10473 -- If it is a type, there is nothing to resolve.
10474 -- If it is a subprogram, do not freeze its profile.
10475 -- If it is an object, complete its resolution.
10477 elsif Is_Overloadable (Entity (P)) then
10478 if not In_Spec_Expression then
10479 Freeze_Before (N, Entity (P), Do_Freeze_Profile => False);
10480 end if;
10482 -- Nothing to do if prefix is a type name
10484 elsif Is_Type (Entity (P)) then
10485 null;
10487 -- Otherwise non-overloaded other case, resolve the prefix
10489 else
10490 Resolve (P);
10491 end if;
10493 -- Some further error checks
10495 Error_Msg_Name_1 := Aname;
10497 if not Is_Entity_Name (P) then
10498 null;
10500 elsif Is_Overloadable (Entity (P))
10501 and then Is_Abstract_Subprogram (Entity (P))
10502 then
10503 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
10504 Set_Etype (N, Any_Type);
10506 elsif Ekind (Entity (P)) = E_Enumeration_Literal then
10507 Error_Msg_F
10508 ("prefix of % attribute cannot be enumeration literal", P);
10509 Set_Etype (N, Any_Type);
10511 -- An attempt to take 'Access of a function that renames an
10512 -- enumeration literal. Issue a specialized error message.
10514 elsif Ekind (Entity (P)) = E_Function
10515 and then Present (Alias (Entity (P)))
10516 and then Ekind (Alias (Entity (P))) = E_Enumeration_Literal
10517 then
10518 Error_Msg_F
10519 ("prefix of % attribute cannot be function renaming "
10520 & "an enumeration literal", P);
10521 Set_Etype (N, Any_Type);
10523 elsif Convention (Entity (P)) = Convention_Intrinsic then
10524 Error_Msg_F ("prefix of % attribute cannot be intrinsic", P);
10525 Set_Etype (N, Any_Type);
10526 end if;
10528 -- Assignments, return statements, components of aggregates,
10529 -- generic instantiations will require convention checks if
10530 -- the type is an access to subprogram. Given that there will
10531 -- also be accessibility checks on those, this is where the
10532 -- checks can eventually be centralized ???
10534 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
10535 E_Access_Subprogram_Type,
10536 E_Anonymous_Access_Protected_Subprogram_Type,
10537 E_Anonymous_Access_Subprogram_Type)
10538 then
10539 -- Deal with convention mismatch
10541 if Convention (Designated_Type (Btyp)) /=
10542 Convention (Entity (P))
10543 then
10544 -- The rule in 6.3.1 (8) deserves a special error
10545 -- message.
10547 if Convention (Btyp) = Convention_Intrinsic
10548 and then Nkind (Parent (N)) = N_Procedure_Call_Statement
10549 and then Is_Entity_Name (Name (Parent (N)))
10550 and then Inside_A_Generic
10551 then
10552 declare
10553 Subp : constant Entity_Id :=
10554 Entity (Name (Parent (N)));
10555 begin
10556 if Convention (Subp) = Convention_Intrinsic then
10557 Error_Msg_FE
10558 ("?subprogram and its formal access "
10559 & "parameters have convention Intrinsic",
10560 Parent (N), Subp);
10561 Error_Msg_N
10562 ("actual cannot be access attribute", N);
10563 end if;
10564 end;
10566 else
10567 Error_Msg_FE
10568 ("subprogram & has wrong convention", P, Entity (P));
10569 Error_Msg_Sloc := Sloc (Btyp);
10570 Error_Msg_FE ("\does not match & declared#", P, Btyp);
10571 end if;
10573 if not Is_Itype (Btyp)
10574 and then not Has_Convention_Pragma (Btyp)
10575 then
10576 Error_Msg_FE
10577 ("\probable missing pragma Convention for &",
10578 P, Btyp);
10579 end if;
10581 else
10582 Check_Subtype_Conformant
10583 (New_Id => Entity (P),
10584 Old_Id => Designated_Type (Btyp),
10585 Err_Loc => P);
10586 end if;
10588 if Attr_Id = Attribute_Unchecked_Access then
10589 Error_Msg_Name_1 := Aname;
10590 Error_Msg_F
10591 ("attribute% cannot be applied to a subprogram", P);
10593 elsif Aname = Name_Unrestricted_Access then
10594 null; -- Nothing to check
10596 -- Check the static accessibility rule of 3.10.2(32).
10597 -- This rule also applies within the private part of an
10598 -- instantiation. This rule does not apply to anonymous
10599 -- access-to-subprogram types in access parameters.
10601 elsif Attr_Id = Attribute_Access
10602 and then not In_Instance_Body
10603 and then
10604 (Ekind (Btyp) = E_Access_Subprogram_Type
10605 or else Is_Local_Anonymous_Access (Btyp))
10606 and then Subprogram_Access_Level (Entity (P)) >
10607 Type_Access_Level (Btyp)
10608 then
10609 Error_Msg_F
10610 ("subprogram must not be deeper than access type", P);
10612 -- Check the restriction of 3.10.2(32) that disallows the
10613 -- access attribute within a generic body when the ultimate
10614 -- ancestor of the type of the attribute is declared outside
10615 -- of the generic unit and the subprogram is declared within
10616 -- that generic unit. This includes any such attribute that
10617 -- occurs within the body of a generic unit that is a child
10618 -- of the generic unit where the subprogram is declared.
10620 -- The rule also prohibits applying the attribute when the
10621 -- access type is a generic formal access type (since the
10622 -- level of the actual type is not known). This restriction
10623 -- does not apply when the attribute type is an anonymous
10624 -- access-to-subprogram type. Note that this check was
10625 -- revised by AI-229, because the original Ada 95 rule
10626 -- was too lax. The original rule only applied when the
10627 -- subprogram was declared within the body of the generic,
10628 -- which allowed the possibility of dangling references).
10629 -- The rule was also too strict in some cases, in that it
10630 -- didn't permit the access to be declared in the generic
10631 -- spec, whereas the revised rule does (as long as it's not
10632 -- a formal type).
10634 -- There are a couple of subtleties of the test for applying
10635 -- the check that are worth noting. First, we only apply it
10636 -- when the levels of the subprogram and access type are the
10637 -- same (the case where the subprogram is statically deeper
10638 -- was applied above, and the case where the type is deeper
10639 -- is always safe). Second, we want the check to apply
10640 -- within nested generic bodies and generic child unit
10641 -- bodies, but not to apply to an attribute that appears in
10642 -- the generic unit's specification. This is done by testing
10643 -- that the attribute's innermost enclosing generic body is
10644 -- not the same as the innermost generic body enclosing the
10645 -- generic unit where the subprogram is declared (we don't
10646 -- want the check to apply when the access attribute is in
10647 -- the spec and there's some other generic body enclosing
10648 -- generic). Finally, there's no point applying the check
10649 -- when within an instance, because any violations will have
10650 -- been caught by the compilation of the generic unit.
10652 -- We relax this check in Relaxed_RM_Semantics mode for
10653 -- compatibility with legacy code for use by Ada source
10654 -- code analyzers (e.g. CodePeer).
10656 elsif Attr_Id = Attribute_Access
10657 and then not Relaxed_RM_Semantics
10658 and then not In_Instance
10659 and then Present (Enclosing_Generic_Unit (Entity (P)))
10660 and then Present (Enclosing_Generic_Body (N))
10661 and then Enclosing_Generic_Body (N) /=
10662 Enclosing_Generic_Body
10663 (Enclosing_Generic_Unit (Entity (P)))
10664 and then Subprogram_Access_Level (Entity (P)) =
10665 Type_Access_Level (Btyp)
10666 and then Ekind (Btyp) /=
10667 E_Anonymous_Access_Subprogram_Type
10668 and then Ekind (Btyp) /=
10669 E_Anonymous_Access_Protected_Subprogram_Type
10670 then
10671 -- The attribute type's ultimate ancestor must be
10672 -- declared within the same generic unit as the
10673 -- subprogram is declared (including within another
10674 -- nested generic unit). The error message is
10675 -- specialized to say "ancestor" for the case where the
10676 -- access type is not its own ancestor, since saying
10677 -- simply "access type" would be very confusing.
10679 if not Declared_Within_Generic_Unit
10680 (Root_Type (Btyp),
10681 Enclosing_Generic_Unit (Entity (P)))
10682 then
10683 Error_Msg_N
10684 ("''Access attribute not allowed in generic body",
10687 if Root_Type (Btyp) = Btyp then
10688 Error_Msg_NE
10689 ("\because " &
10690 "access type & is declared outside " &
10691 "generic unit (RM 3.10.2(32))", N, Btyp);
10692 else
10693 Error_Msg_NE
10694 ("\because ancestor of " &
10695 "access type & is declared outside " &
10696 "generic unit (RM 3.10.2(32))", N, Btyp);
10697 end if;
10699 Error_Msg_NE
10700 ("\move ''Access to private part, or " &
10701 "(Ada 2005) use anonymous access type instead of &",
10702 N, Btyp);
10704 -- If the ultimate ancestor of the attribute's type is
10705 -- a formal type, then the attribute is illegal because
10706 -- the actual type might be declared at a higher level.
10707 -- The error message is specialized to say "ancestor"
10708 -- for the case where the access type is not its own
10709 -- ancestor, since saying simply "access type" would be
10710 -- very confusing.
10712 elsif Is_Generic_Type (Root_Type (Btyp)) then
10713 if Root_Type (Btyp) = Btyp then
10714 Error_Msg_N
10715 ("access type must not be a generic formal type",
10717 else
10718 Error_Msg_N
10719 ("ancestor access type must not be a generic " &
10720 "formal type", N);
10721 end if;
10722 end if;
10723 end if;
10724 end if;
10726 -- If this is a renaming, an inherited operation, or a
10727 -- subprogram instance, use the original entity. This may make
10728 -- the node type-inconsistent, so this transformation can only
10729 -- be done if the node will not be reanalyzed. In particular,
10730 -- if it is within a default expression, the transformation
10731 -- must be delayed until the default subprogram is created for
10732 -- it, when the enclosing subprogram is frozen.
10734 if Is_Entity_Name (P)
10735 and then Is_Overloadable (Entity (P))
10736 and then Present (Alias (Entity (P)))
10737 and then Expander_Active
10738 then
10739 Rewrite (P,
10740 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
10741 end if;
10743 elsif Nkind (P) = N_Selected_Component
10744 and then Is_Overloadable (Entity (Selector_Name (P)))
10745 then
10746 -- Protected operation. If operation is overloaded, must
10747 -- disambiguate. Prefix that denotes protected object itself
10748 -- is resolved with its own type.
10750 if Attr_Id = Attribute_Unchecked_Access then
10751 Error_Msg_Name_1 := Aname;
10752 Error_Msg_F
10753 ("attribute% cannot be applied to protected operation", P);
10754 end if;
10756 Resolve (Prefix (P));
10757 Generate_Reference (Entity (Selector_Name (P)), P);
10759 -- Implement check implied by 3.10.2 (18.1/2) : F.all'access is
10760 -- statically illegal if F is an anonymous access to subprogram.
10762 elsif Nkind (P) = N_Explicit_Dereference
10763 and then Is_Entity_Name (Prefix (P))
10764 and then Ekind (Etype (Entity (Prefix (P)))) =
10765 E_Anonymous_Access_Subprogram_Type
10766 then
10767 Error_Msg_N ("anonymous access to subprogram "
10768 & "has deeper accessibility than any master", P);
10770 elsif Is_Overloaded (P) then
10772 -- Use the designated type of the context to disambiguate
10773 -- Note that this was not strictly conformant to Ada 95,
10774 -- but was the implementation adopted by most Ada 95 compilers.
10775 -- The use of the context type to resolve an Access attribute
10776 -- reference is now mandated in AI-235 for Ada 2005.
10778 declare
10779 Index : Interp_Index;
10780 It : Interp;
10782 begin
10783 Get_First_Interp (P, Index, It);
10784 while Present (It.Typ) loop
10785 if Covers (Designated_Type (Typ), It.Typ) then
10786 Resolve (P, It.Typ);
10787 exit;
10788 end if;
10790 Get_Next_Interp (Index, It);
10791 end loop;
10792 end;
10793 else
10794 Resolve (P);
10795 end if;
10797 -- X'Access is illegal if X denotes a constant and the access type
10798 -- is access-to-variable. Same for 'Unchecked_Access. The rule
10799 -- does not apply to 'Unrestricted_Access. If the reference is a
10800 -- default-initialized aggregate component for a self-referential
10801 -- type the reference is legal.
10803 if not (Ekind (Btyp) = E_Access_Subprogram_Type
10804 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
10805 or else (Is_Record_Type (Btyp)
10806 and then
10807 Present (Corresponding_Remote_Type (Btyp)))
10808 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
10809 or else Ekind (Btyp)
10810 = E_Anonymous_Access_Protected_Subprogram_Type
10811 or else Is_Access_Constant (Btyp)
10812 or else Is_Variable (P)
10813 or else Attr_Id = Attribute_Unrestricted_Access)
10814 then
10815 if Is_Entity_Name (P)
10816 and then Is_Type (Entity (P))
10817 then
10818 -- Legality of a self-reference through an access
10819 -- attribute has been verified in Analyze_Access_Attribute.
10821 null;
10823 elsif Comes_From_Source (N) then
10824 Error_Msg_F ("access-to-variable designates constant", P);
10825 end if;
10826 end if;
10828 Des_Btyp := Designated_Type (Btyp);
10830 if Ada_Version >= Ada_2005
10831 and then Is_Incomplete_Type (Des_Btyp)
10832 then
10833 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
10834 -- imported entity, and the non-limited view is visible, make
10835 -- use of it. If it is an incomplete subtype, use the base type
10836 -- in any case.
10838 if From_Limited_With (Des_Btyp)
10839 and then Present (Non_Limited_View (Des_Btyp))
10840 then
10841 Des_Btyp := Non_Limited_View (Des_Btyp);
10843 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
10844 Des_Btyp := Etype (Des_Btyp);
10845 end if;
10846 end if;
10848 if (Attr_Id = Attribute_Access
10849 or else
10850 Attr_Id = Attribute_Unchecked_Access)
10851 and then (Ekind (Btyp) = E_General_Access_Type
10852 or else Ekind (Btyp) = E_Anonymous_Access_Type)
10853 then
10854 -- Ada 2005 (AI-230): Check the accessibility of anonymous
10855 -- access types for stand-alone objects, record and array
10856 -- components, and return objects. For a component definition
10857 -- the level is the same of the enclosing composite type.
10859 if Ada_Version >= Ada_2005
10860 and then (Is_Local_Anonymous_Access (Btyp)
10862 -- Handle cases where Btyp is the anonymous access
10863 -- type of an Ada 2012 stand-alone object.
10865 or else Nkind (Associated_Node_For_Itype (Btyp)) =
10866 N_Object_Declaration)
10867 and then
10868 Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
10869 and then Attr_Id = Attribute_Access
10870 then
10871 -- In an instance, this is a runtime check, but one we know
10872 -- will fail, so generate an appropriate warning. As usual,
10873 -- this kind of warning is an error in SPARK mode.
10875 if In_Instance_Body then
10876 Error_Msg_Warn := SPARK_Mode /= On;
10877 Error_Msg_F
10878 ("non-local pointer cannot point to local object<<", P);
10879 Error_Msg_F ("\Program_Error [<<", P);
10881 Rewrite (N,
10882 Make_Raise_Program_Error (Loc,
10883 Reason => PE_Accessibility_Check_Failed));
10884 Set_Etype (N, Typ);
10886 else
10887 Error_Msg_F
10888 ("non-local pointer cannot point to local object", P);
10889 end if;
10890 end if;
10892 if Is_Dependent_Component_Of_Mutable_Object (P) then
10893 Error_Msg_F
10894 ("illegal attribute for discriminant-dependent component",
10896 end if;
10898 -- Check static matching rule of 3.10.2(27). Nominal subtype
10899 -- of the prefix must statically match the designated type.
10901 Nom_Subt := Etype (P);
10903 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
10904 Nom_Subt := Base_Type (Nom_Subt);
10905 end if;
10907 if Is_Tagged_Type (Designated_Type (Typ)) then
10909 -- If the attribute is in the context of an access
10910 -- parameter, then the prefix is allowed to be of
10911 -- the class-wide type (by AI-127).
10913 if Ekind (Typ) = E_Anonymous_Access_Type then
10914 if not Covers (Designated_Type (Typ), Nom_Subt)
10915 and then not Covers (Nom_Subt, Designated_Type (Typ))
10916 then
10917 declare
10918 Desig : Entity_Id;
10920 begin
10921 Desig := Designated_Type (Typ);
10923 if Is_Class_Wide_Type (Desig) then
10924 Desig := Etype (Desig);
10925 end if;
10927 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
10928 null;
10930 else
10931 Error_Msg_FE
10932 ("type of prefix: & not compatible",
10933 P, Nom_Subt);
10934 Error_Msg_FE
10935 ("\with &, the expected designated type",
10936 P, Designated_Type (Typ));
10937 end if;
10938 end;
10939 end if;
10941 elsif not Covers (Designated_Type (Typ), Nom_Subt)
10942 or else
10943 (not Is_Class_Wide_Type (Designated_Type (Typ))
10944 and then Is_Class_Wide_Type (Nom_Subt))
10945 then
10946 Error_Msg_FE
10947 ("type of prefix: & is not covered", P, Nom_Subt);
10948 Error_Msg_FE
10949 ("\by &, the expected designated type" &
10950 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
10951 end if;
10953 if Is_Class_Wide_Type (Designated_Type (Typ))
10954 and then Has_Discriminants (Etype (Designated_Type (Typ)))
10955 and then Is_Constrained (Etype (Designated_Type (Typ)))
10956 and then Designated_Type (Typ) /= Nom_Subt
10957 then
10958 Apply_Discriminant_Check
10959 (N, Etype (Designated_Type (Typ)));
10960 end if;
10962 -- Ada 2005 (AI-363): Require static matching when designated
10963 -- type has discriminants and a constrained partial view, since
10964 -- in general objects of such types are mutable, so we can't
10965 -- allow the access value to designate a constrained object
10966 -- (because access values must be assumed to designate mutable
10967 -- objects when designated type does not impose a constraint).
10969 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
10970 null;
10972 elsif Has_Discriminants (Designated_Type (Typ))
10973 and then not Is_Constrained (Des_Btyp)
10974 and then
10975 (Ada_Version < Ada_2005
10976 or else
10977 not Object_Type_Has_Constrained_Partial_View
10978 (Typ => Designated_Type (Base_Type (Typ)),
10979 Scop => Current_Scope))
10980 then
10981 null;
10983 else
10984 Error_Msg_F
10985 ("object subtype must statically match "
10986 & "designated subtype", P);
10988 if Is_Entity_Name (P)
10989 and then Is_Array_Type (Designated_Type (Typ))
10990 then
10991 declare
10992 D : constant Node_Id := Declaration_Node (Entity (P));
10993 begin
10994 Error_Msg_N
10995 ("aliased object has explicit bounds??", D);
10996 Error_Msg_N
10997 ("\declare without bounds (and with explicit "
10998 & "initialization)??", D);
10999 Error_Msg_N
11000 ("\for use with unconstrained access??", D);
11001 end;
11002 end if;
11003 end if;
11005 -- Check the static accessibility rule of 3.10.2(28). Note that
11006 -- this check is not performed for the case of an anonymous
11007 -- access type, since the access attribute is always legal
11008 -- in such a context.
11010 if Attr_Id /= Attribute_Unchecked_Access
11011 and then Ekind (Btyp) = E_General_Access_Type
11012 and then
11013 Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
11014 then
11015 Accessibility_Message;
11016 return;
11017 end if;
11018 end if;
11020 if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
11021 E_Anonymous_Access_Protected_Subprogram_Type)
11022 then
11023 if Is_Entity_Name (P)
11024 and then not Is_Protected_Type (Scope (Entity (P)))
11025 then
11026 Error_Msg_F ("context requires a protected subprogram", P);
11028 -- Check accessibility of protected object against that of the
11029 -- access type, but only on user code, because the expander
11030 -- creates access references for handlers. If the context is an
11031 -- anonymous_access_to_protected, there are no accessibility
11032 -- checks either. Omit check entirely for Unrestricted_Access.
11034 elsif Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
11035 and then Comes_From_Source (N)
11036 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
11037 and then Attr_Id /= Attribute_Unrestricted_Access
11038 then
11039 Accessibility_Message;
11040 return;
11042 -- AI05-0225: If the context is not an access to protected
11043 -- function, the prefix must be a variable, given that it may
11044 -- be used subsequently in a protected call.
11046 elsif Nkind (P) = N_Selected_Component
11047 and then not Is_Variable (Prefix (P))
11048 and then Ekind (Entity (Selector_Name (P))) /= E_Function
11049 then
11050 Error_Msg_N
11051 ("target object of access to protected procedure "
11052 & "must be variable", N);
11054 elsif Is_Entity_Name (P) then
11055 Check_Internal_Protected_Use (N, Entity (P));
11056 end if;
11058 elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
11059 E_Anonymous_Access_Subprogram_Type)
11060 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
11061 then
11062 Error_Msg_F ("context requires a non-protected subprogram", P);
11063 end if;
11065 -- The context cannot be a pool-specific type, but this is a
11066 -- legality rule, not a resolution rule, so it must be checked
11067 -- separately, after possibly disambiguation (see AI-245).
11069 if Ekind (Btyp) = E_Access_Type
11070 and then Attr_Id /= Attribute_Unrestricted_Access
11071 then
11072 Wrong_Type (N, Typ);
11073 end if;
11075 -- The context may be a constrained access type (however ill-
11076 -- advised such subtypes might be) so in order to generate a
11077 -- constraint check when needed set the type of the attribute
11078 -- reference to the base type of the context.
11080 Set_Etype (N, Btyp);
11082 -- Check for incorrect atomic/volatile reference (RM C.6(12))
11084 if Attr_Id /= Attribute_Unrestricted_Access then
11085 if Is_Atomic_Object (P)
11086 and then not Is_Atomic (Designated_Type (Typ))
11087 then
11088 Error_Msg_F
11089 ("access to atomic object cannot yield access-to-" &
11090 "non-atomic type", P);
11092 elsif Is_Volatile_Object (P)
11093 and then not Is_Volatile (Designated_Type (Typ))
11094 then
11095 Error_Msg_F
11096 ("access to volatile object cannot yield access-to-" &
11097 "non-volatile type", P);
11098 end if;
11099 end if;
11101 -- Check for aliased view. We allow a nonaliased prefix when in
11102 -- an instance because the prefix may have been a tagged formal
11103 -- object, which is defined to be aliased even when the actual
11104 -- might not be (other instance cases will have been caught in
11105 -- the generic). Similarly, within an inlined body we know that
11106 -- the attribute is legal in the original subprogram, therefore
11107 -- legal in the expansion.
11109 if not (Is_Entity_Name (P)
11110 and then Is_Overloadable (Entity (P)))
11111 and then not (Nkind (P) = N_Selected_Component
11112 and then
11113 Is_Overloadable (Entity (Selector_Name (P))))
11114 and then not Is_Aliased_View (Original_Node (P))
11115 and then not In_Instance
11116 and then not In_Inlined_Body
11117 and then Comes_From_Source (N)
11118 then
11119 -- Here we have a non-aliased view. This is illegal unless we
11120 -- have the case of Unrestricted_Access, where for now we allow
11121 -- this (we will reject later if expected type is access to an
11122 -- unconstrained array with a thin pointer).
11124 -- No need for an error message on a generated access reference
11125 -- for the controlling argument in a dispatching call: error
11126 -- will be reported when resolving the call.
11128 if Attr_Id /= Attribute_Unrestricted_Access then
11129 Error_Msg_N ("prefix of % attribute must be aliased", P);
11131 -- Check for unrestricted access where expected type is a thin
11132 -- pointer to an unconstrained array.
11134 elsif Has_Size_Clause (Typ)
11135 and then RM_Size (Typ) = System_Address_Size
11136 then
11137 declare
11138 DT : constant Entity_Id := Designated_Type (Typ);
11139 begin
11140 if Is_Array_Type (DT)
11141 and then not Is_Constrained (DT)
11142 then
11143 Error_Msg_N
11144 ("illegal use of Unrestricted_Access attribute", P);
11145 Error_Msg_N
11146 ("\attempt to generate thin pointer to unaliased "
11147 & "object", P);
11148 end if;
11149 end;
11150 end if;
11151 end if;
11153 -- Mark that address of entity is taken in case of
11154 -- 'Unrestricted_Access or in case of a subprogram.
11156 if Is_Entity_Name (P)
11157 and then (Attr_Id = Attribute_Unrestricted_Access
11158 or else Is_Subprogram (Entity (P)))
11159 then
11160 Set_Address_Taken (Entity (P));
11161 end if;
11163 -- Deal with possible elaboration check
11165 if Is_Entity_Name (P) and then Is_Subprogram (Entity (P)) then
11166 declare
11167 Subp_Id : constant Entity_Id := Entity (P);
11168 Scop : constant Entity_Id := Scope (Subp_Id);
11169 Subp_Decl : constant Node_Id :=
11170 Unit_Declaration_Node (Subp_Id);
11171 Flag_Id : Entity_Id;
11172 Subp_Body : Node_Id;
11174 -- If the access has been taken and the body of the subprogram
11175 -- has not been see yet, indirect calls must be protected with
11176 -- elaboration checks. We have the proper elaboration machinery
11177 -- for subprograms declared in packages, but within a block or
11178 -- a subprogram the body will appear in the same declarative
11179 -- part, and we must insert a check in the eventual body itself
11180 -- using the elaboration flag that we generate now. The check
11181 -- is then inserted when the body is expanded. This processing
11182 -- is not needed for a stand alone expression function because
11183 -- the internally generated spec and body are always inserted
11184 -- as a pair in the same declarative list.
11186 begin
11187 if Expander_Active
11188 and then Comes_From_Source (Subp_Id)
11189 and then Comes_From_Source (N)
11190 and then In_Open_Scopes (Scop)
11191 and then Ekind_In (Scop, E_Block, E_Procedure, E_Function)
11192 and then not Has_Completion (Subp_Id)
11193 and then No (Elaboration_Entity (Subp_Id))
11194 and then Nkind (Subp_Decl) = N_Subprogram_Declaration
11195 and then Nkind (Original_Node (Subp_Decl)) /=
11196 N_Expression_Function
11197 then
11198 -- Create elaboration variable for it
11200 Flag_Id := Make_Temporary (Loc, 'E');
11201 Set_Elaboration_Entity (Subp_Id, Flag_Id);
11202 Set_Is_Frozen (Flag_Id);
11204 -- Insert declaration for flag after subprogram
11205 -- declaration. Note that attribute reference may
11206 -- appear within a nested scope.
11208 Insert_After_And_Analyze (Subp_Decl,
11209 Make_Object_Declaration (Loc,
11210 Defining_Identifier => Flag_Id,
11211 Object_Definition =>
11212 New_Occurrence_Of (Standard_Short_Integer, Loc),
11213 Expression =>
11214 Make_Integer_Literal (Loc, Uint_0)));
11215 end if;
11217 -- Taking the 'Access of an expression function freezes its
11218 -- expression (RM 13.14 10.3/3). This does not apply to an
11219 -- expression function that acts as a completion because the
11220 -- generated body is immediately analyzed and the expression
11221 -- is automatically frozen.
11223 if Is_Expression_Function (Subp_Id)
11224 and then Present (Corresponding_Body (Subp_Decl))
11225 then
11226 Subp_Body :=
11227 Unit_Declaration_Node (Corresponding_Body (Subp_Decl));
11229 -- The body has already been analyzed when the expression
11230 -- function acts as a completion.
11232 if Analyzed (Subp_Body) then
11233 null;
11235 -- Attribute 'Access may appear within the generated body
11236 -- of the expression function subject to the attribute:
11238 -- function F is (... F'Access ...);
11240 -- If the expression function is on the scope stack, then
11241 -- the body is currently being analyzed. Do not reanalyze
11242 -- it because this will lead to infinite recursion.
11244 elsif In_Open_Scopes (Subp_Id) then
11245 null;
11247 -- If reference to the expression function appears in an
11248 -- inner scope, for example as an actual in an instance,
11249 -- this is not a freeze point either.
11251 elsif Scope (Subp_Id) /= Current_Scope then
11252 null;
11254 -- Analyze the body of the expression function to freeze
11255 -- the expression. This takes care of the case where the
11256 -- 'Access is part of dispatch table initialization and
11257 -- the generated body of the expression function has not
11258 -- been analyzed yet.
11260 else
11261 Analyze (Subp_Body);
11262 end if;
11263 end if;
11264 end;
11265 end if;
11267 -------------
11268 -- Address --
11269 -------------
11271 -- Deal with resolving the type for Address attribute, overloading
11272 -- is not permitted here, since there is no context to resolve it.
11274 when Attribute_Address
11275 | Attribute_Code_Address
11277 -- To be safe, assume that if the address of a variable is taken,
11278 -- it may be modified via this address, so note modification.
11280 if Is_Variable (P) then
11281 Note_Possible_Modification (P, Sure => False);
11282 end if;
11284 if Nkind (P) in N_Subexpr
11285 and then Is_Overloaded (P)
11286 then
11287 Get_First_Interp (P, Index, It);
11288 Get_Next_Interp (Index, It);
11290 if Present (It.Nam) then
11291 Error_Msg_Name_1 := Aname;
11292 Error_Msg_F
11293 ("prefix of % attribute cannot be overloaded", P);
11294 end if;
11295 end if;
11297 if not Is_Entity_Name (P)
11298 or else not Is_Overloadable (Entity (P))
11299 then
11300 if not Is_Task_Type (Etype (P))
11301 or else Nkind (P) = N_Explicit_Dereference
11302 then
11303 Resolve (P);
11304 end if;
11305 end if;
11307 -- If this is the name of a derived subprogram, or that of a
11308 -- generic actual, the address is that of the original entity.
11310 if Is_Entity_Name (P)
11311 and then Is_Overloadable (Entity (P))
11312 and then Present (Alias (Entity (P)))
11313 then
11314 Rewrite (P,
11315 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
11316 end if;
11318 if Is_Entity_Name (P) then
11319 Set_Address_Taken (Entity (P));
11320 end if;
11322 if Nkind (P) = N_Slice then
11324 -- Arr (X .. Y)'address is identical to Arr (X)'address,
11325 -- even if the array is packed and the slice itself is not
11326 -- addressable. Transform the prefix into an indexed component.
11328 -- Note that the transformation is safe only if we know that
11329 -- the slice is non-null. That is because a null slice can have
11330 -- an out of bounds index value.
11332 -- Right now, gigi blows up if given 'Address on a slice as a
11333 -- result of some incorrect freeze nodes generated by the front
11334 -- end, and this covers up that bug in one case, but the bug is
11335 -- likely still there in the cases not handled by this code ???
11337 -- It's not clear what 'Address *should* return for a null
11338 -- slice with out of bounds indexes, this might be worth an ARG
11339 -- discussion ???
11341 -- One approach would be to do a length check unconditionally,
11342 -- and then do the transformation below unconditionally, but
11343 -- analyze with checks off, avoiding the problem of the out of
11344 -- bounds index. This approach would interpret the address of
11345 -- an out of bounds null slice as being the address where the
11346 -- array element would be if there was one, which is probably
11347 -- as reasonable an interpretation as any ???
11349 declare
11350 Loc : constant Source_Ptr := Sloc (P);
11351 D : constant Node_Id := Discrete_Range (P);
11352 Lo : Node_Id;
11354 begin
11355 if Is_Entity_Name (D)
11356 and then
11357 Not_Null_Range
11358 (Type_Low_Bound (Entity (D)),
11359 Type_High_Bound (Entity (D)))
11360 then
11361 Lo :=
11362 Make_Attribute_Reference (Loc,
11363 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
11364 Attribute_Name => Name_First);
11366 elsif Nkind (D) = N_Range
11367 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
11368 then
11369 Lo := Low_Bound (D);
11371 else
11372 Lo := Empty;
11373 end if;
11375 if Present (Lo) then
11376 Rewrite (P,
11377 Make_Indexed_Component (Loc,
11378 Prefix => Relocate_Node (Prefix (P)),
11379 Expressions => New_List (Lo)));
11381 Analyze_And_Resolve (P);
11382 end if;
11383 end;
11384 end if;
11386 ------------------
11387 -- Body_Version --
11388 ------------------
11390 -- Prefix of Body_Version attribute can be a subprogram name which
11391 -- must not be resolved, since this is not a call.
11393 when Attribute_Body_Version =>
11394 null;
11396 ------------
11397 -- Caller --
11398 ------------
11400 -- Prefix of Caller attribute is an entry name which must not
11401 -- be resolved, since this is definitely not an entry call.
11403 when Attribute_Caller =>
11404 null;
11406 ------------------
11407 -- Code_Address --
11408 ------------------
11410 -- Shares processing with Address attribute
11412 -----------
11413 -- Count --
11414 -----------
11416 -- If the prefix of the Count attribute is an entry name it must not
11417 -- be resolved, since this is definitely not an entry call. However,
11418 -- if it is an element of an entry family, the index itself may
11419 -- have to be resolved because it can be a general expression.
11421 when Attribute_Count =>
11422 if Nkind (P) = N_Indexed_Component
11423 and then Is_Entity_Name (Prefix (P))
11424 then
11425 declare
11426 Indx : constant Node_Id := First (Expressions (P));
11427 Fam : constant Entity_Id := Entity (Prefix (P));
11428 begin
11429 Resolve (Indx, Entry_Index_Type (Fam));
11430 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
11431 end;
11432 end if;
11434 ----------------
11435 -- Elaborated --
11436 ----------------
11438 -- Prefix of the Elaborated attribute is a subprogram name which
11439 -- must not be resolved, since this is definitely not a call. Note
11440 -- that it is a library unit, so it cannot be overloaded here.
11442 when Attribute_Elaborated =>
11443 null;
11445 -------------
11446 -- Enabled --
11447 -------------
11449 -- Prefix of Enabled attribute is a check name, which must be treated
11450 -- specially and not touched by Resolve.
11452 when Attribute_Enabled =>
11453 null;
11455 ----------------
11456 -- Loop_Entry --
11457 ----------------
11459 -- Do not resolve the prefix of Loop_Entry, instead wait until the
11460 -- attribute has been expanded (see Expand_Loop_Entry_Attributes).
11461 -- The delay ensures that any generated checks or temporaries are
11462 -- inserted before the relocated prefix.
11464 when Attribute_Loop_Entry =>
11465 null;
11467 --------------------
11468 -- Mechanism_Code --
11469 --------------------
11471 -- Prefix of the Mechanism_Code attribute is a function name
11472 -- which must not be resolved. Should we check for overloaded ???
11474 when Attribute_Mechanism_Code =>
11475 null;
11477 ------------------
11478 -- Partition_ID --
11479 ------------------
11481 -- Most processing is done in sem_dist, after determining the
11482 -- context type. Node is rewritten as a conversion to a runtime call.
11484 when Attribute_Partition_ID =>
11485 Process_Partition_Id (N);
11486 return;
11488 ------------------
11489 -- Pool_Address --
11490 ------------------
11492 when Attribute_Pool_Address =>
11493 Resolve (P);
11495 -----------
11496 -- Range --
11497 -----------
11499 -- We replace the Range attribute node with a range expression whose
11500 -- bounds are the 'First and 'Last attributes applied to the same
11501 -- prefix. The reason that we do this transformation here instead of
11502 -- in the expander is that it simplifies other parts of the semantic
11503 -- analysis which assume that the Range has been replaced; thus it
11504 -- must be done even when in semantic-only mode (note that the RM
11505 -- specifically mentions this equivalence, we take care that the
11506 -- prefix is only evaluated once).
11508 when Attribute_Range => Range_Attribute : declare
11509 Dims : List_Id;
11510 HB : Node_Id;
11511 LB : Node_Id;
11513 begin
11514 if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then
11515 Resolve (P);
11516 end if;
11518 Dims := Expressions (N);
11520 HB :=
11521 Make_Attribute_Reference (Loc,
11522 Prefix => Duplicate_Subexpr (P, Name_Req => True),
11523 Attribute_Name => Name_Last,
11524 Expressions => Dims);
11526 LB :=
11527 Make_Attribute_Reference (Loc,
11528 Prefix => P,
11529 Attribute_Name => Name_First,
11530 Expressions => (Dims));
11532 -- Do not share the dimension indicator, if present. Even though
11533 -- it is a static constant, its source location may be modified
11534 -- when printing expanded code and node sharing will lead to chaos
11535 -- in Sprint.
11537 if Present (Dims) then
11538 Set_Expressions (LB, New_List (New_Copy_Tree (First (Dims))));
11539 end if;
11541 -- If the original was marked as Must_Not_Freeze (see code in
11542 -- Sem_Ch3.Make_Index), then make sure the rewriting does not
11543 -- freeze either.
11545 if Must_Not_Freeze (N) then
11546 Set_Must_Not_Freeze (HB);
11547 Set_Must_Not_Freeze (LB);
11548 Set_Must_Not_Freeze (Prefix (HB));
11549 Set_Must_Not_Freeze (Prefix (LB));
11550 end if;
11552 if Raises_Constraint_Error (Prefix (N)) then
11554 -- Preserve Sloc of prefix in the new bounds, so that the
11555 -- posted warning can be removed if we are within unreachable
11556 -- code.
11558 Set_Sloc (LB, Sloc (Prefix (N)));
11559 Set_Sloc (HB, Sloc (Prefix (N)));
11560 end if;
11562 Rewrite (N, Make_Range (Loc, LB, HB));
11563 Analyze_And_Resolve (N, Typ);
11565 -- Ensure that the expanded range does not have side effects
11567 Force_Evaluation (LB);
11568 Force_Evaluation (HB);
11570 -- Normally after resolving attribute nodes, Eval_Attribute
11571 -- is called to do any possible static evaluation of the node.
11572 -- However, here since the Range attribute has just been
11573 -- transformed into a range expression it is no longer an
11574 -- attribute node and therefore the call needs to be avoided
11575 -- and is accomplished by simply returning from the procedure.
11577 return;
11578 end Range_Attribute;
11580 ------------
11581 -- Result --
11582 ------------
11584 -- We will only come here during the prescan of a spec expression
11585 -- containing a Result attribute. In that case the proper Etype has
11586 -- already been set, and nothing more needs to be done here.
11588 when Attribute_Result =>
11589 null;
11591 ----------------------
11592 -- Unchecked_Access --
11593 ----------------------
11595 -- Processing is shared with Access
11597 -------------------------
11598 -- Unrestricted_Access --
11599 -------------------------
11601 -- Processing is shared with Access
11603 ------------
11604 -- Update --
11605 ------------
11607 -- Resolve aggregate components in component associations
11609 when Attribute_Update => Update : declare
11610 Aggr : constant Node_Id := First (Expressions (N));
11611 Typ : constant Entity_Id := Etype (Prefix (N));
11612 Assoc : Node_Id;
11613 Comp : Node_Id;
11614 Expr : Node_Id;
11616 begin
11617 -- Set the Etype of the aggregate to that of the prefix, even
11618 -- though the aggregate may not be a proper representation of a
11619 -- value of the type (missing or duplicated associations, etc.)
11620 -- Complete resolution of the prefix. Note that in Ada 2012 it
11621 -- can be a qualified expression that is e.g. an aggregate.
11623 Set_Etype (Aggr, Typ);
11624 Resolve (Prefix (N), Typ);
11626 -- For an array type, resolve expressions with the component type
11627 -- of the array, and apply constraint checks when needed.
11629 if Is_Array_Type (Typ) then
11630 Assoc := First (Component_Associations (Aggr));
11631 while Present (Assoc) loop
11632 Expr := Expression (Assoc);
11633 Resolve (Expr, Component_Type (Typ));
11635 -- For scalar array components set Do_Range_Check when
11636 -- needed. Constraint checking on non-scalar components
11637 -- is done in Aggregate_Constraint_Checks, but only if
11638 -- full analysis is enabled. These flags are not set in
11639 -- the front-end in GnatProve mode.
11641 if Is_Scalar_Type (Component_Type (Typ))
11642 and then not Is_OK_Static_Expression (Expr)
11643 and then not Range_Checks_Suppressed (Component_Type (Typ))
11644 then
11645 if Is_Entity_Name (Expr)
11646 and then Etype (Expr) = Component_Type (Typ)
11647 then
11648 null;
11650 else
11651 Set_Do_Range_Check (Expr);
11652 end if;
11653 end if;
11655 -- The choices in the association are static constants,
11656 -- or static aggregates each of whose components belongs
11657 -- to the proper index type. However, they must also
11658 -- belong to the index subtype (s) of the prefix, which
11659 -- may be a subtype (e.g. given by a slice).
11661 -- Choices may also be identifiers with no staticness
11662 -- requirements, in which case they must resolve to the
11663 -- index type.
11665 declare
11666 C : Node_Id;
11667 C_E : Node_Id;
11668 Indx : Node_Id;
11670 begin
11671 C := First (Choices (Assoc));
11672 while Present (C) loop
11673 Indx := First_Index (Etype (Prefix (N)));
11675 if Nkind (C) /= N_Aggregate then
11676 Analyze_And_Resolve (C, Etype (Indx));
11677 Apply_Constraint_Check (C, Etype (Indx));
11678 Check_Non_Static_Context (C);
11680 else
11681 C_E := First (Expressions (C));
11682 while Present (C_E) loop
11683 Analyze_And_Resolve (C_E, Etype (Indx));
11684 Apply_Constraint_Check (C_E, Etype (Indx));
11685 Check_Non_Static_Context (C_E);
11687 Next (C_E);
11688 Next_Index (Indx);
11689 end loop;
11690 end if;
11692 Next (C);
11693 end loop;
11694 end;
11696 Next (Assoc);
11697 end loop;
11699 -- For a record type, use type of each component, which is
11700 -- recorded during analysis.
11702 else
11703 Assoc := First (Component_Associations (Aggr));
11704 while Present (Assoc) loop
11705 Comp := First (Choices (Assoc));
11706 Expr := Expression (Assoc);
11708 if Nkind (Comp) /= N_Others_Choice
11709 and then not Error_Posted (Comp)
11710 then
11711 Resolve (Expr, Etype (Entity (Comp)));
11713 if Is_Scalar_Type (Etype (Entity (Comp)))
11714 and then not Is_OK_Static_Expression (Expr)
11715 and then not Range_Checks_Suppressed
11716 (Etype (Entity (Comp)))
11717 then
11718 Set_Do_Range_Check (Expr);
11719 end if;
11720 end if;
11722 Next (Assoc);
11723 end loop;
11724 end if;
11725 end Update;
11727 ---------
11728 -- Val --
11729 ---------
11731 -- Apply range check. Note that we did not do this during the
11732 -- analysis phase, since we wanted Eval_Attribute to have a
11733 -- chance at finding an illegal out of range value.
11735 when Attribute_Val =>
11737 -- Note that we do our own Eval_Attribute call here rather than
11738 -- use the common one, because we need to do processing after
11739 -- the call, as per above comment.
11741 Eval_Attribute (N);
11743 -- Eval_Attribute may replace the node with a raise CE, or
11744 -- fold it to a constant. Obviously we only apply a scalar
11745 -- range check if this did not happen.
11747 if Nkind (N) = N_Attribute_Reference
11748 and then Attribute_Name (N) = Name_Val
11749 then
11750 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
11751 end if;
11753 return;
11755 -------------
11756 -- Version --
11757 -------------
11759 -- Prefix of Version attribute can be a subprogram name which
11760 -- must not be resolved, since this is not a call.
11762 when Attribute_Version =>
11763 null;
11765 ----------------------
11766 -- Other Attributes --
11767 ----------------------
11769 -- For other attributes, resolve prefix unless it is a type. If
11770 -- the attribute reference itself is a type name ('Base and 'Class)
11771 -- then this is only legal within a task or protected record.
11773 when others =>
11774 if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then
11775 Resolve (P);
11776 end if;
11778 -- If the attribute reference itself is a type name ('Base,
11779 -- 'Class) then this is only legal within a task or protected
11780 -- record. What is this all about ???
11782 if Is_Entity_Name (N) and then Is_Type (Entity (N)) then
11783 if Is_Concurrent_Type (Entity (N))
11784 and then In_Open_Scopes (Entity (P))
11785 then
11786 null;
11787 else
11788 Error_Msg_N
11789 ("invalid use of subtype name in expression or call", N);
11790 end if;
11791 end if;
11793 -- For attributes whose argument may be a string, complete
11794 -- resolution of argument now. This avoids premature expansion
11795 -- (and the creation of transient scopes) before the attribute
11796 -- reference is resolved.
11798 case Attr_Id is
11799 when Attribute_Value =>
11800 Resolve (First (Expressions (N)), Standard_String);
11802 when Attribute_Wide_Value =>
11803 Resolve (First (Expressions (N)), Standard_Wide_String);
11805 when Attribute_Wide_Wide_Value =>
11806 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
11808 when others => null;
11809 end case;
11811 -- If the prefix of the attribute is a class-wide type then it
11812 -- will be expanded into a dispatching call to a predefined
11813 -- primitive. Therefore we must check for potential violation
11814 -- of such restriction.
11816 if Is_Class_Wide_Type (Etype (P)) then
11817 Check_Restriction (No_Dispatching_Calls, N);
11818 end if;
11819 end case;
11821 -- Mark use clauses of the original prefix if the attribute is applied
11822 -- to an entity.
11824 if Nkind (Original_Node (P)) in N_Has_Entity
11825 and then Present (Entity (Original_Node (P)))
11826 then
11827 Mark_Use_Clauses (Original_Node (P));
11828 end if;
11830 -- Normally the Freezing is done by Resolve but sometimes the Prefix
11831 -- is not resolved, in which case the freezing must be done now.
11833 -- For an elaboration check on a subprogram, we do not freeze its type.
11834 -- It may be declared in an unrelated scope, in particular in the case
11835 -- of a generic function whose type may remain unelaborated.
11837 if Attr_Id = Attribute_Elaborated then
11838 null;
11840 else
11841 Freeze_Expression (P);
11842 end if;
11844 -- Finally perform static evaluation on the attribute reference
11846 Analyze_Dimension (N);
11847 Eval_Attribute (N);
11848 end Resolve_Attribute;
11850 ------------------------
11851 -- Set_Boolean_Result --
11852 ------------------------
11854 procedure Set_Boolean_Result (N : Node_Id; B : Boolean) is
11855 Loc : constant Source_Ptr := Sloc (N);
11856 begin
11857 if B then
11858 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
11859 else
11860 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
11861 end if;
11862 end Set_Boolean_Result;
11864 -------------------------------
11865 -- Statically_Denotes_Object --
11866 -------------------------------
11868 function Statically_Denotes_Object (N : Node_Id) return Boolean is
11869 Indx : Node_Id;
11871 begin
11872 if Is_Entity_Name (N) then
11873 return True;
11875 elsif Nkind (N) = N_Selected_Component
11876 and then Statically_Denotes_Object (Prefix (N))
11877 and then Present (Entity (Selector_Name (N)))
11878 then
11879 declare
11880 Sel_Id : constant Entity_Id := Entity (Selector_Name (N));
11881 Comp_Decl : constant Node_Id := Parent (Sel_Id);
11883 begin
11884 if Depends_On_Discriminant (Sel_Id) then
11885 return False;
11887 elsif Nkind (Parent (Parent (Comp_Decl))) = N_Variant then
11888 return False;
11890 else
11891 return True;
11892 end if;
11893 end;
11895 elsif Nkind (N) = N_Indexed_Component
11896 and then Statically_Denotes_Object (Prefix (N))
11897 and then Is_Constrained (Etype (Prefix (N)))
11898 then
11899 Indx := First (Expressions (N));
11900 while Present (Indx) loop
11901 if not Compile_Time_Known_Value (Indx)
11902 or else Do_Range_Check (Indx)
11903 then
11904 return False;
11905 end if;
11907 Next (Indx);
11908 end loop;
11910 return True;
11912 else
11913 return False;
11914 end if;
11915 end Statically_Denotes_Object;
11917 --------------------------------
11918 -- Stream_Attribute_Available --
11919 --------------------------------
11921 function Stream_Attribute_Available
11922 (Typ : Entity_Id;
11923 Nam : TSS_Name_Type;
11924 Partial_View : Node_Id := Empty) return Boolean
11926 Etyp : Entity_Id := Typ;
11928 -- Start of processing for Stream_Attribute_Available
11930 begin
11931 -- We need some comments in this body ???
11933 if Has_Stream_Attribute_Definition (Typ, Nam) then
11934 return True;
11935 end if;
11937 if Is_Class_Wide_Type (Typ) then
11938 return not Is_Limited_Type (Typ)
11939 or else Stream_Attribute_Available (Etype (Typ), Nam);
11940 end if;
11942 if Nam = TSS_Stream_Input
11943 and then Is_Abstract_Type (Typ)
11944 and then not Is_Class_Wide_Type (Typ)
11945 then
11946 return False;
11947 end if;
11949 if not (Is_Limited_Type (Typ)
11950 or else (Present (Partial_View)
11951 and then Is_Limited_Type (Partial_View)))
11952 then
11953 return True;
11954 end if;
11956 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
11958 if Nam = TSS_Stream_Input
11959 and then Ada_Version >= Ada_2005
11960 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
11961 then
11962 return True;
11964 elsif Nam = TSS_Stream_Output
11965 and then Ada_Version >= Ada_2005
11966 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
11967 then
11968 return True;
11969 end if;
11971 -- Case of Read and Write: check for attribute definition clause that
11972 -- applies to an ancestor type.
11974 while Etype (Etyp) /= Etyp loop
11975 Etyp := Etype (Etyp);
11977 if Has_Stream_Attribute_Definition (Etyp, Nam) then
11978 return True;
11979 end if;
11980 end loop;
11982 if Ada_Version < Ada_2005 then
11984 -- In Ada 95 mode, also consider a non-visible definition
11986 declare
11987 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
11988 begin
11989 return Btyp /= Typ
11990 and then Stream_Attribute_Available
11991 (Btyp, Nam, Partial_View => Typ);
11992 end;
11993 end if;
11995 return False;
11996 end Stream_Attribute_Available;
11998 end Sem_Attr;