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[official-gcc.git] / gcc / ada / sem_ch13.adb
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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ C H 1 3 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2005, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
26
27 with Atree; use Atree;
28 with Checks; use Checks;
29 with Einfo; use Einfo;
30 with Errout; use Errout;
31 with Exp_Tss; use Exp_Tss;
32 with Exp_Util; use Exp_Util;
33 with Lib; use Lib;
34 with Nlists; use Nlists;
35 with Nmake; use Nmake;
36 with Opt; use Opt;
37 with Restrict; use Restrict;
38 with Rident; use Rident;
39 with Rtsfind; use Rtsfind;
40 with Sem; use Sem;
41 with Sem_Ch8; use Sem_Ch8;
42 with Sem_Eval; use Sem_Eval;
43 with Sem_Res; use Sem_Res;
44 with Sem_Type; use Sem_Type;
45 with Sem_Util; use Sem_Util;
46 with Snames; use Snames;
47 with Stand; use Stand;
48 with Sinfo; use Sinfo;
49 with Table;
50 with Targparm; use Targparm;
51 with Ttypes; use Ttypes;
52 with Tbuild; use Tbuild;
53 with Urealp; use Urealp;
54
55 with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
56
57 package body Sem_Ch13 is
58
59 SSU : constant Pos := System_Storage_Unit;
60 -- Convenient short hand for commonly used constant
61
62 -----------------------
63 -- Local Subprograms --
64 -----------------------
65
66 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id);
67 -- This routine is called after setting the Esize of type entity Typ.
68 -- The purpose is to deal with the situation where an aligment has been
69 -- inherited from a derived type that is no longer appropriate for the
70 -- new Esize value. In this case, we reset the Alignment to unknown.
71
72 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id);
73 -- Given two entities for record components or discriminants, checks
74 -- if they hav overlapping component clauses and issues errors if so.
75
76 function Get_Alignment_Value (Expr : Node_Id) return Uint;
77 -- Given the expression for an alignment value, returns the corresponding
78 -- Uint value. If the value is inappropriate, then error messages are
79 -- posted as required, and a value of No_Uint is returned.
80
81 function Is_Operational_Item (N : Node_Id) return Boolean;
82 -- A specification for a stream attribute is allowed before the full
83 -- type is declared, as explained in AI-00137 and the corrigendum.
84 -- Attributes that do not specify a representation characteristic are
85 -- operational attributes.
86
87 function Address_Aliased_Entity (N : Node_Id) return Entity_Id;
88 -- If expression N is of the form E'Address, return E
89
90 procedure Mark_Aliased_Address_As_Volatile (N : Node_Id);
91 -- This is used for processing of an address representation clause. If
92 -- the expression N is of the form of K'Address, then the entity that
93 -- is associated with K is marked as volatile.
94
95 procedure New_Stream_Function
96 (N : Node_Id;
97 Ent : Entity_Id;
98 Subp : Entity_Id;
99 Nam : TSS_Name_Type);
100 -- Create a function renaming of a given stream attribute to the
101 -- designated subprogram and then in the tagged case, provide this as
102 -- a primitive operation, or in the non-tagged case make an appropriate
103 -- TSS entry. Used for Input. This is more properly an expansion activity
104 -- than just semantics, but the presence of user-defined stream functions
105 -- for limited types is a legality check, which is why this takes place
106 -- here rather than in exp_ch13, where it was previously. Nam indicates
107 -- the name of the TSS function to be generated.
108 --
109 -- To avoid elaboration anomalies with freeze nodes, for untagged types
110 -- we generate both a subprogram declaration and a subprogram renaming
111 -- declaration, so that the attribute specification is handled as a
112 -- renaming_as_body. For tagged types, the specification is one of the
113 -- primitive specs.
114
115 procedure New_Stream_Procedure
116 (N : Node_Id;
117 Ent : Entity_Id;
118 Subp : Entity_Id;
119 Nam : TSS_Name_Type;
120 Out_P : Boolean := False);
121 -- Create a procedure renaming of a given stream attribute to the
122 -- designated subprogram and then in the tagged case, provide this as
123 -- a primitive operation, or in the non-tagged case make an appropriate
124 -- TSS entry. Used for Read, Output, Write. Nam indicates the name of
125 -- the TSS procedure to be generated.
126
127 ----------------------------------------------
128 -- Table for Validate_Unchecked_Conversions --
129 ----------------------------------------------
130
131 -- The following table collects unchecked conversions for validation.
132 -- Entries are made by Validate_Unchecked_Conversion and then the
133 -- call to Validate_Unchecked_Conversions does the actual error
134 -- checking and posting of warnings. The reason for this delayed
135 -- processing is to take advantage of back-annotations of size and
136 -- alignment values peformed by the back end.
137
138 type UC_Entry is record
139 Enode : Node_Id; -- node used for posting warnings
140 Source : Entity_Id; -- source type for unchecked conversion
141 Target : Entity_Id; -- target type for unchecked conversion
142 end record;
143
144 package Unchecked_Conversions is new Table.Table (
145 Table_Component_Type => UC_Entry,
146 Table_Index_Type => Int,
147 Table_Low_Bound => 1,
148 Table_Initial => 50,
149 Table_Increment => 200,
150 Table_Name => "Unchecked_Conversions");
151
152 ----------------------------
153 -- Address_Aliased_Entity --
154 ----------------------------
155
156 function Address_Aliased_Entity (N : Node_Id) return Entity_Id is
157 begin
158 if Nkind (N) = N_Attribute_Reference
159 and then Attribute_Name (N) = Name_Address
160 then
161 declare
162 Nam : Node_Id := Prefix (N);
163 begin
164 while False
165 or else Nkind (Nam) = N_Selected_Component
166 or else Nkind (Nam) = N_Indexed_Component
167 loop
168 Nam := Prefix (Nam);
169 end loop;
170
171 if Is_Entity_Name (Nam) then
172 return Entity (Nam);
173 end if;
174 end;
175 end if;
176
177 return Empty;
178 end Address_Aliased_Entity;
179
180 --------------------------------------
181 -- Alignment_Check_For_Esize_Change --
182 --------------------------------------
183
184 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is
185 begin
186 -- If the alignment is known, and not set by a rep clause, and is
187 -- inconsistent with the size being set, then reset it to unknown,
188 -- we assume in this case that the size overrides the inherited
189 -- alignment, and that the alignment must be recomputed.
190
191 if Known_Alignment (Typ)
192 and then not Has_Alignment_Clause (Typ)
193 and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0
194 then
195 Init_Alignment (Typ);
196 end if;
197 end Alignment_Check_For_Esize_Change;
198
199 -----------------------
200 -- Analyze_At_Clause --
201 -----------------------
202
203 -- An at clause is replaced by the corresponding Address attribute
204 -- definition clause that is the preferred approach in Ada 95.
205
206 procedure Analyze_At_Clause (N : Node_Id) is
207 begin
208 Check_Restriction (No_Obsolescent_Features, N);
209
210 if Warn_On_Obsolescent_Feature then
211 Error_Msg_N
212 ("at clause is an obsolescent feature ('R'M 'J.7(2))?", N);
213 Error_Msg_N
214 ("\use address attribute definition clause instead?", N);
215 end if;
216
217 Rewrite (N,
218 Make_Attribute_Definition_Clause (Sloc (N),
219 Name => Identifier (N),
220 Chars => Name_Address,
221 Expression => Expression (N)));
222 Analyze_Attribute_Definition_Clause (N);
223 end Analyze_At_Clause;
224
225 -----------------------------------------
226 -- Analyze_Attribute_Definition_Clause --
227 -----------------------------------------
228
229 procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is
230 Loc : constant Source_Ptr := Sloc (N);
231 Nam : constant Node_Id := Name (N);
232 Attr : constant Name_Id := Chars (N);
233 Expr : constant Node_Id := Expression (N);
234 Id : constant Attribute_Id := Get_Attribute_Id (Attr);
235 Ent : Entity_Id;
236 U_Ent : Entity_Id;
237
238 FOnly : Boolean := False;
239 -- Reset to True for subtype specific attribute (Alignment, Size)
240 -- and for stream attributes, i.e. those cases where in the call
241 -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing
242 -- rules are checked. Note that the case of stream attributes is not
243 -- clear from the RM, but see AI95-00137. Also, the RM seems to
244 -- disallow Storage_Size for derived task types, but that is also
245 -- clearly unintentional.
246
247 begin
248 Analyze (Nam);
249 Ent := Entity (Nam);
250
251 if Rep_Item_Too_Early (Ent, N) then
252 return;
253 end if;
254
255 -- Rep clause applies to full view of incomplete type or private type
256 -- if we have one (if not, this is a premature use of the type).
257 -- However, certain semantic checks need to be done on the specified
258 -- entity (i.e. the private view), so we save it in Ent.
259
260 if Is_Private_Type (Ent)
261 and then Is_Derived_Type (Ent)
262 and then not Is_Tagged_Type (Ent)
263 and then No (Full_View (Ent))
264 then
265 -- If this is a private type whose completion is a derivation
266 -- from another private type, there is no full view, and the
267 -- attribute belongs to the type itself, not its underlying parent.
268
269 U_Ent := Ent;
270
271 elsif Ekind (Ent) = E_Incomplete_Type then
272
273 -- The attribute applies to the full view, set the entity
274 -- of the attribute definition accordingly.
275
276 Ent := Underlying_Type (Ent);
277 U_Ent := Ent;
278 Set_Entity (Nam, Ent);
279
280 else
281 U_Ent := Underlying_Type (Ent);
282 end if;
283
284 -- Complete other routine error checks
285
286 if Etype (Nam) = Any_Type then
287 return;
288
289 elsif Scope (Ent) /= Current_Scope then
290 Error_Msg_N ("entity must be declared in this scope", Nam);
291 return;
292
293 elsif No (U_Ent) then
294 U_Ent := Ent;
295
296 elsif Is_Type (U_Ent)
297 and then not Is_First_Subtype (U_Ent)
298 and then Id /= Attribute_Object_Size
299 and then Id /= Attribute_Value_Size
300 and then not From_At_Mod (N)
301 then
302 Error_Msg_N ("cannot specify attribute for subtype", Nam);
303 return;
304 end if;
305
306 -- Switch on particular attribute
307
308 case Id is
309
310 -------------
311 -- Address --
312 -------------
313
314 -- Address attribute definition clause
315
316 when Attribute_Address => Address : begin
317 Analyze_And_Resolve (Expr, RTE (RE_Address));
318
319 if Present (Address_Clause (U_Ent)) then
320 Error_Msg_N ("address already given for &", Nam);
321
322 -- Case of address clause for subprogram
323
324 elsif Is_Subprogram (U_Ent) then
325 if Has_Homonym (U_Ent) then
326 Error_Msg_N
327 ("address clause cannot be given " &
328 "for overloaded subprogram",
329 Nam);
330 end if;
331
332 -- For subprograms, all address clauses are permitted,
333 -- and we mark the subprogram as having a deferred freeze
334 -- so that Gigi will not elaborate it too soon.
335
336 -- Above needs more comments, what is too soon about???
337
338 Set_Has_Delayed_Freeze (U_Ent);
339
340 -- Case of address clause for entry
341
342 elsif Ekind (U_Ent) = E_Entry then
343 if Nkind (Parent (N)) = N_Task_Body then
344 Error_Msg_N
345 ("entry address must be specified in task spec", Nam);
346 end if;
347
348 -- For entries, we require a constant address
349
350 Check_Constant_Address_Clause (Expr, U_Ent);
351
352 if Is_Task_Type (Scope (U_Ent))
353 and then Comes_From_Source (Scope (U_Ent))
354 then
355 Error_Msg_N
356 ("?entry address declared for entry in task type", N);
357 Error_Msg_N
358 ("\?only one task can be declared of this type", N);
359 end if;
360
361 Check_Restriction (No_Obsolescent_Features, N);
362
363 if Warn_On_Obsolescent_Feature then
364 Error_Msg_N
365 ("attaching interrupt to task entry is an " &
366 "obsolescent feature ('R'M 'J.7.1)?", N);
367 Error_Msg_N
368 ("\use interrupt procedure instead?", N);
369 end if;
370
371 -- Case of an address clause for a controlled object:
372 -- erroneous execution.
373
374 elsif Is_Controlled (Etype (U_Ent)) then
375 Error_Msg_NE
376 ("?controlled object& must not be overlaid", Nam, U_Ent);
377 Error_Msg_N
378 ("\?Program_Error will be raised at run time", Nam);
379 Insert_Action (Declaration_Node (U_Ent),
380 Make_Raise_Program_Error (Loc,
381 Reason => PE_Overlaid_Controlled_Object));
382
383 -- Case of address clause for a (non-controlled) object
384
385 elsif
386 Ekind (U_Ent) = E_Variable
387 or else
388 Ekind (U_Ent) = E_Constant
389 then
390 declare
391 Expr : constant Node_Id := Expression (N);
392 Aent : constant Entity_Id := Address_Aliased_Entity (Expr);
393
394 begin
395 -- Exported variables cannot have an address clause,
396 -- because this cancels the effect of the pragma Export
397
398 if Is_Exported (U_Ent) then
399 Error_Msg_N
400 ("cannot export object with address clause", Nam);
401
402 -- Overlaying controlled objects is erroneous
403
404 elsif Present (Aent)
405 and then Is_Controlled (Etype (Aent))
406 then
407 Error_Msg_N
408 ("?controlled object must not be overlaid", Expr);
409 Error_Msg_N
410 ("\?Program_Error will be raised at run time", Expr);
411 Insert_Action (Declaration_Node (U_Ent),
412 Make_Raise_Program_Error (Loc,
413 Reason => PE_Overlaid_Controlled_Object));
414
415 elsif Present (Aent)
416 and then Ekind (U_Ent) = E_Constant
417 and then Ekind (Aent) /= E_Constant
418 then
419 Error_Msg_N ("constant overlays a variable?", Expr);
420
421 elsif Present (Renamed_Object (U_Ent)) then
422 Error_Msg_N
423 ("address clause not allowed"
424 & " for a renaming declaration ('R'M 13.1(6))", Nam);
425
426 -- Imported variables can have an address clause, but then
427 -- the import is pretty meaningless except to suppress
428 -- initializations, so we do not need such variables to
429 -- be statically allocated (and in fact it causes trouble
430 -- if the address clause is a local value).
431
432 elsif Is_Imported (U_Ent) then
433 Set_Is_Statically_Allocated (U_Ent, False);
434 end if;
435
436 -- We mark a possible modification of a variable with an
437 -- address clause, since it is likely aliasing is occurring.
438
439 Note_Possible_Modification (Nam);
440
441 -- Here we are checking for explicit overlap of one
442 -- variable by another, and if we find this, then we
443 -- mark the overlapped variable as also being aliased.
444
445 -- First case is where we have an explicit
446
447 -- for J'Address use K'Address;
448
449 -- In this case, we mark K as volatile
450
451 Mark_Aliased_Address_As_Volatile (Expr);
452
453 -- Second case is where we have a constant whose
454 -- definition is of the form of an adress as in:
455
456 -- A : constant Address := K'Address;
457 -- ...
458 -- for B'Address use A;
459
460 -- In this case we also mark K as volatile
461
462 if Is_Entity_Name (Expr) then
463 declare
464 Ent : constant Entity_Id := Entity (Expr);
465 Decl : constant Node_Id := Declaration_Node (Ent);
466
467 begin
468 if Ekind (Ent) = E_Constant
469 and then Nkind (Decl) = N_Object_Declaration
470 and then Present (Expression (Decl))
471 then
472 Mark_Aliased_Address_As_Volatile
473 (Expression (Decl));
474 end if;
475 end;
476 end if;
477
478 -- Legality checks on the address clause for initialized
479 -- objects is deferred until the freeze point, because
480 -- a subsequent pragma might indicate that the object is
481 -- imported and thus not initialized.
482
483 Set_Has_Delayed_Freeze (U_Ent);
484
485 if Is_Exported (U_Ent) then
486 Error_Msg_N
487 ("& cannot be exported if an address clause is given",
488 Nam);
489 Error_Msg_N
490 ("\define and export a variable " &
491 "that holds its address instead",
492 Nam);
493 end if;
494
495 -- Entity has delayed freeze, so we will generate
496 -- an alignment check at the freeze point.
497
498 Set_Check_Address_Alignment
499 (N, not Range_Checks_Suppressed (U_Ent));
500
501 -- Kill the size check code, since we are not allocating
502 -- the variable, it is somewhere else.
503
504 Kill_Size_Check_Code (U_Ent);
505 end;
506
507 -- Not a valid entity for an address clause
508
509 else
510 Error_Msg_N ("address cannot be given for &", Nam);
511 end if;
512 end Address;
513
514 ---------------
515 -- Alignment --
516 ---------------
517
518 -- Alignment attribute definition clause
519
520 when Attribute_Alignment => Alignment_Block : declare
521 Align : constant Uint := Get_Alignment_Value (Expr);
522
523 begin
524 FOnly := True;
525
526 if not Is_Type (U_Ent)
527 and then Ekind (U_Ent) /= E_Variable
528 and then Ekind (U_Ent) /= E_Constant
529 then
530 Error_Msg_N ("alignment cannot be given for &", Nam);
531
532 elsif Has_Alignment_Clause (U_Ent) then
533 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
534 Error_Msg_N ("alignment clause previously given#", N);
535
536 elsif Align /= No_Uint then
537 Set_Has_Alignment_Clause (U_Ent);
538 Set_Alignment (U_Ent, Align);
539 end if;
540 end Alignment_Block;
541
542 ---------------
543 -- Bit_Order --
544 ---------------
545
546 -- Bit_Order attribute definition clause
547
548 when Attribute_Bit_Order => Bit_Order : declare
549 begin
550 if not Is_Record_Type (U_Ent) then
551 Error_Msg_N
552 ("Bit_Order can only be defined for record type", Nam);
553
554 else
555 Analyze_And_Resolve (Expr, RTE (RE_Bit_Order));
556
557 if Etype (Expr) = Any_Type then
558 return;
559
560 elsif not Is_Static_Expression (Expr) then
561 Flag_Non_Static_Expr
562 ("Bit_Order requires static expression!", Expr);
563
564 else
565 if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then
566 Set_Reverse_Bit_Order (U_Ent, True);
567 end if;
568 end if;
569 end if;
570 end Bit_Order;
571
572 --------------------
573 -- Component_Size --
574 --------------------
575
576 -- Component_Size attribute definition clause
577
578 when Attribute_Component_Size => Component_Size_Case : declare
579 Csize : constant Uint := Static_Integer (Expr);
580 Btype : Entity_Id;
581 Biased : Boolean;
582 New_Ctyp : Entity_Id;
583 Decl : Node_Id;
584
585 begin
586 if not Is_Array_Type (U_Ent) then
587 Error_Msg_N ("component size requires array type", Nam);
588 return;
589 end if;
590
591 Btype := Base_Type (U_Ent);
592
593 if Has_Component_Size_Clause (Btype) then
594 Error_Msg_N
595 ("component size clase for& previously given", Nam);
596
597 elsif Csize /= No_Uint then
598 Check_Size (Expr, Component_Type (Btype), Csize, Biased);
599
600 if Has_Aliased_Components (Btype)
601 and then Csize < 32
602 and then Csize /= 8
603 and then Csize /= 16
604 then
605 Error_Msg_N
606 ("component size incorrect for aliased components", N);
607 return;
608 end if;
609
610 -- For the biased case, build a declaration for a subtype
611 -- that will be used to represent the biased subtype that
612 -- reflects the biased representation of components. We need
613 -- this subtype to get proper conversions on referencing
614 -- elements of the array.
615
616 if Biased then
617 New_Ctyp :=
618 Make_Defining_Identifier (Loc,
619 Chars => New_External_Name (Chars (U_Ent), 'C', 0, 'T'));
620
621 Decl :=
622 Make_Subtype_Declaration (Loc,
623 Defining_Identifier => New_Ctyp,
624 Subtype_Indication =>
625 New_Occurrence_Of (Component_Type (Btype), Loc));
626
627 Set_Parent (Decl, N);
628 Analyze (Decl, Suppress => All_Checks);
629
630 Set_Has_Delayed_Freeze (New_Ctyp, False);
631 Set_Esize (New_Ctyp, Csize);
632 Set_RM_Size (New_Ctyp, Csize);
633 Init_Alignment (New_Ctyp);
634 Set_Has_Biased_Representation (New_Ctyp, True);
635 Set_Is_Itype (New_Ctyp, True);
636 Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
637
638 Set_Component_Type (Btype, New_Ctyp);
639 end if;
640
641 Set_Component_Size (Btype, Csize);
642 Set_Has_Component_Size_Clause (Btype, True);
643 Set_Has_Non_Standard_Rep (Btype, True);
644 end if;
645 end Component_Size_Case;
646
647 ------------------
648 -- External_Tag --
649 ------------------
650
651 when Attribute_External_Tag => External_Tag :
652 begin
653 if not Is_Tagged_Type (U_Ent) then
654 Error_Msg_N ("should be a tagged type", Nam);
655 end if;
656
657 Analyze_And_Resolve (Expr, Standard_String);
658
659 if not Is_Static_Expression (Expr) then
660 Flag_Non_Static_Expr
661 ("static string required for tag name!", Nam);
662 end if;
663
664 Set_Has_External_Tag_Rep_Clause (U_Ent);
665 end External_Tag;
666
667 -----------
668 -- Input --
669 -----------
670
671 when Attribute_Input => Input : declare
672 Subp : Entity_Id := Empty;
673 I : Interp_Index;
674 It : Interp;
675 Pnam : Entity_Id;
676
677 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
678 -- Return true if the entity is a function with an appropriate
679 -- profile for the Input attribute.
680
681 ----------------------
682 -- Has_Good_Profile --
683 ----------------------
684
685 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
686 F : Entity_Id;
687 Ok : Boolean := False;
688
689 begin
690 if Ekind (Subp) = E_Function then
691 F := First_Formal (Subp);
692
693 if Present (F) and then No (Next_Formal (F)) then
694 if Ekind (Etype (F)) = E_Anonymous_Access_Type
695 and then
696 Designated_Type (Etype (F)) =
697 Class_Wide_Type (RTE (RE_Root_Stream_Type))
698 then
699 Ok := Base_Type (Etype (Subp)) = Base_Type (Ent);
700 end if;
701 end if;
702 end if;
703
704 return Ok;
705 end Has_Good_Profile;
706
707 -- Start of processing for Input attribute definition
708
709 begin
710 FOnly := True;
711
712 if not Is_Type (U_Ent) then
713 Error_Msg_N ("local name must be a subtype", Nam);
714 return;
715
716 else
717 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Input);
718
719 if Present (Pnam)
720 and then Base_Type (Etype (Pnam)) = Base_Type (U_Ent)
721 then
722 Error_Msg_Sloc := Sloc (Pnam);
723 Error_Msg_N ("input attribute already defined #", Nam);
724 return;
725 end if;
726 end if;
727
728 Analyze (Expr);
729
730 if Is_Entity_Name (Expr) then
731 if not Is_Overloaded (Expr) then
732 if Has_Good_Profile (Entity (Expr)) then
733 Subp := Entity (Expr);
734 end if;
735
736 else
737 Get_First_Interp (Expr, I, It);
738
739 while Present (It.Nam) loop
740 if Has_Good_Profile (It.Nam) then
741 Subp := It.Nam;
742 exit;
743 end if;
744
745 Get_Next_Interp (I, It);
746 end loop;
747 end if;
748 end if;
749
750 if Present (Subp) then
751 Set_Entity (Expr, Subp);
752 Set_Etype (Expr, Etype (Subp));
753 New_Stream_Function (N, U_Ent, Subp, TSS_Stream_Input);
754 else
755 Error_Msg_N ("incorrect expression for input attribute", Expr);
756 return;
757 end if;
758 end Input;
759
760 -------------------
761 -- Machine_Radix --
762 -------------------
763
764 -- Machine radix attribute definition clause
765
766 when Attribute_Machine_Radix => Machine_Radix : declare
767 Radix : constant Uint := Static_Integer (Expr);
768
769 begin
770 if not Is_Decimal_Fixed_Point_Type (U_Ent) then
771 Error_Msg_N ("decimal fixed-point type expected for &", Nam);
772
773 elsif Has_Machine_Radix_Clause (U_Ent) then
774 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
775 Error_Msg_N ("machine radix clause previously given#", N);
776
777 elsif Radix /= No_Uint then
778 Set_Has_Machine_Radix_Clause (U_Ent);
779 Set_Has_Non_Standard_Rep (Base_Type (U_Ent));
780
781 if Radix = 2 then
782 null;
783 elsif Radix = 10 then
784 Set_Machine_Radix_10 (U_Ent);
785 else
786 Error_Msg_N ("machine radix value must be 2 or 10", Expr);
787 end if;
788 end if;
789 end Machine_Radix;
790
791 -----------------
792 -- Object_Size --
793 -----------------
794
795 -- Object_Size attribute definition clause
796
797 when Attribute_Object_Size => Object_Size : declare
798 Size : constant Uint := Static_Integer (Expr);
799 Biased : Boolean;
800
801 begin
802 if not Is_Type (U_Ent) then
803 Error_Msg_N ("Object_Size cannot be given for &", Nam);
804
805 elsif Has_Object_Size_Clause (U_Ent) then
806 Error_Msg_N ("Object_Size already given for &", Nam);
807
808 else
809 Check_Size (Expr, U_Ent, Size, Biased);
810
811 if Size /= 8
812 and then
813 Size /= 16
814 and then
815 Size /= 32
816 and then
817 UI_Mod (Size, 64) /= 0
818 then
819 Error_Msg_N
820 ("Object_Size must be 8, 16, 32, or multiple of 64",
821 Expr);
822 end if;
823
824 Set_Esize (U_Ent, Size);
825 Set_Has_Object_Size_Clause (U_Ent);
826 Alignment_Check_For_Esize_Change (U_Ent);
827 end if;
828 end Object_Size;
829
830 ------------
831 -- Output --
832 ------------
833
834 when Attribute_Output => Output : declare
835 Subp : Entity_Id := Empty;
836 I : Interp_Index;
837 It : Interp;
838 Pnam : Entity_Id;
839
840 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
841 -- Return true if the entity is a procedure with an
842 -- appropriate profile for the output attribute.
843
844 ----------------------
845 -- Has_Good_Profile --
846 ----------------------
847
848 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
849 F : Entity_Id;
850 Ok : Boolean := False;
851
852 begin
853 if Ekind (Subp) = E_Procedure then
854 F := First_Formal (Subp);
855
856 if Present (F) then
857 if Ekind (Etype (F)) = E_Anonymous_Access_Type
858 and then
859 Designated_Type (Etype (F)) =
860 Class_Wide_Type (RTE (RE_Root_Stream_Type))
861 then
862 Next_Formal (F);
863 Ok := Present (F)
864 and then Parameter_Mode (F) = E_In_Parameter
865 and then Base_Type (Etype (F)) = Base_Type (Ent)
866 and then No (Next_Formal (F));
867 end if;
868 end if;
869 end if;
870
871 return Ok;
872 end Has_Good_Profile;
873
874 -- Start of processing for Output attribute definition
875
876 begin
877 FOnly := True;
878
879 if not Is_Type (U_Ent) then
880 Error_Msg_N ("local name must be a subtype", Nam);
881 return;
882
883 else
884 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Output);
885
886 if Present (Pnam)
887 and then
888 Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
889 = Base_Type (U_Ent)
890 then
891 Error_Msg_Sloc := Sloc (Pnam);
892 Error_Msg_N ("output attribute already defined #", Nam);
893 return;
894 end if;
895 end if;
896
897 Analyze (Expr);
898
899 if Is_Entity_Name (Expr) then
900 if not Is_Overloaded (Expr) then
901 if Has_Good_Profile (Entity (Expr)) then
902 Subp := Entity (Expr);
903 end if;
904
905 else
906 Get_First_Interp (Expr, I, It);
907
908 while Present (It.Nam) loop
909 if Has_Good_Profile (It.Nam) then
910 Subp := It.Nam;
911 exit;
912 end if;
913
914 Get_Next_Interp (I, It);
915 end loop;
916 end if;
917 end if;
918
919 if Present (Subp) then
920 Set_Entity (Expr, Subp);
921 Set_Etype (Expr, Etype (Subp));
922 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Output);
923 else
924 Error_Msg_N ("incorrect expression for output attribute", Expr);
925 return;
926 end if;
927 end Output;
928
929 ----------
930 -- Read --
931 ----------
932
933 when Attribute_Read => Read : declare
934 Subp : Entity_Id := Empty;
935 I : Interp_Index;
936 It : Interp;
937 Pnam : Entity_Id;
938
939 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
940 -- Return true if the entity is a procedure with an appropriate
941 -- profile for the Read attribute.
942
943 ----------------------
944 -- Has_Good_Profile --
945 ----------------------
946
947 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
948 F : Entity_Id;
949 Ok : Boolean := False;
950
951 begin
952 if Ekind (Subp) = E_Procedure then
953 F := First_Formal (Subp);
954
955 if Present (F) then
956 if Ekind (Etype (F)) = E_Anonymous_Access_Type
957 and then
958 Designated_Type (Etype (F)) =
959 Class_Wide_Type (RTE (RE_Root_Stream_Type))
960 then
961 Next_Formal (F);
962 Ok := Present (F)
963 and then Parameter_Mode (F) = E_Out_Parameter
964 and then Base_Type (Etype (F)) = Base_Type (Ent)
965 and then No (Next_Formal (F));
966 end if;
967 end if;
968 end if;
969
970 return Ok;
971 end Has_Good_Profile;
972
973 -- Start of processing for Read attribute definition
974
975 begin
976 FOnly := True;
977
978 if not Is_Type (U_Ent) then
979 Error_Msg_N ("local name must be a subtype", Nam);
980 return;
981
982 else
983 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Read);
984
985 if Present (Pnam)
986 and then Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
987 = Base_Type (U_Ent)
988 then
989 Error_Msg_Sloc := Sloc (Pnam);
990 Error_Msg_N ("read attribute already defined #", Nam);
991 return;
992 end if;
993 end if;
994
995 Analyze (Expr);
996
997 if Is_Entity_Name (Expr) then
998 if not Is_Overloaded (Expr) then
999 if Has_Good_Profile (Entity (Expr)) then
1000 Subp := Entity (Expr);
1001 end if;
1002
1003 else
1004 Get_First_Interp (Expr, I, It);
1005
1006 while Present (It.Nam) loop
1007 if Has_Good_Profile (It.Nam) then
1008 Subp := It.Nam;
1009 exit;
1010 end if;
1011
1012 Get_Next_Interp (I, It);
1013 end loop;
1014 end if;
1015 end if;
1016
1017 if Present (Subp) then
1018 Set_Entity (Expr, Subp);
1019 Set_Etype (Expr, Etype (Subp));
1020 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Read, True);
1021 else
1022 Error_Msg_N ("incorrect expression for read attribute", Expr);
1023 return;
1024 end if;
1025 end Read;
1026
1027 ----------
1028 -- Size --
1029 ----------
1030
1031 -- Size attribute definition clause
1032
1033 when Attribute_Size => Size : declare
1034 Size : constant Uint := Static_Integer (Expr);
1035 Etyp : Entity_Id;
1036 Biased : Boolean;
1037
1038 begin
1039 FOnly := True;
1040
1041 if Has_Size_Clause (U_Ent) then
1042 Error_Msg_N ("size already given for &", Nam);
1043
1044 elsif not Is_Type (U_Ent)
1045 and then Ekind (U_Ent) /= E_Variable
1046 and then Ekind (U_Ent) /= E_Constant
1047 then
1048 Error_Msg_N ("size cannot be given for &", Nam);
1049
1050 elsif Is_Array_Type (U_Ent)
1051 and then not Is_Constrained (U_Ent)
1052 then
1053 Error_Msg_N
1054 ("size cannot be given for unconstrained array", Nam);
1055
1056 elsif Size /= No_Uint then
1057 if Is_Type (U_Ent) then
1058 Etyp := U_Ent;
1059 else
1060 Etyp := Etype (U_Ent);
1061 end if;
1062
1063 -- Check size, note that Gigi is in charge of checking
1064 -- that the size of an array or record type is OK. Also
1065 -- we do not check the size in the ordinary fixed-point
1066 -- case, since it is too early to do so (there may be a
1067 -- subsequent small clause that affects the size). We can
1068 -- check the size if a small clause has already been given.
1069
1070 if not Is_Ordinary_Fixed_Point_Type (U_Ent)
1071 or else Has_Small_Clause (U_Ent)
1072 then
1073 Check_Size (Expr, Etyp, Size, Biased);
1074 Set_Has_Biased_Representation (U_Ent, Biased);
1075 end if;
1076
1077 -- For types set RM_Size and Esize if possible
1078
1079 if Is_Type (U_Ent) then
1080 Set_RM_Size (U_Ent, Size);
1081
1082 -- For scalar types, increase Object_Size to power of 2,
1083 -- but not less than a storage unit in any case (i.e.,
1084 -- normally this means it will be byte addressable).
1085
1086 if Is_Scalar_Type (U_Ent) then
1087 if Size <= System_Storage_Unit then
1088 Init_Esize (U_Ent, System_Storage_Unit);
1089 elsif Size <= 16 then
1090 Init_Esize (U_Ent, 16);
1091 elsif Size <= 32 then
1092 Init_Esize (U_Ent, 32);
1093 else
1094 Set_Esize (U_Ent, (Size + 63) / 64 * 64);
1095 end if;
1096
1097 -- For all other types, object size = value size. The
1098 -- backend will adjust as needed.
1099
1100 else
1101 Set_Esize (U_Ent, Size);
1102 end if;
1103
1104 Alignment_Check_For_Esize_Change (U_Ent);
1105
1106 -- For objects, set Esize only
1107
1108 else
1109 if Is_Elementary_Type (Etyp) then
1110 if Size /= System_Storage_Unit
1111 and then
1112 Size /= System_Storage_Unit * 2
1113 and then
1114 Size /= System_Storage_Unit * 4
1115 and then
1116 Size /= System_Storage_Unit * 8
1117 then
1118 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1119 Error_Msg_N
1120 ("size for primitive object must be a power of 2"
1121 & " and at least ^", N);
1122 end if;
1123 end if;
1124
1125 Set_Esize (U_Ent, Size);
1126 end if;
1127
1128 Set_Has_Size_Clause (U_Ent);
1129 end if;
1130 end Size;
1131
1132 -----------
1133 -- Small --
1134 -----------
1135
1136 -- Small attribute definition clause
1137
1138 when Attribute_Small => Small : declare
1139 Implicit_Base : constant Entity_Id := Base_Type (U_Ent);
1140 Small : Ureal;
1141
1142 begin
1143 Analyze_And_Resolve (Expr, Any_Real);
1144
1145 if Etype (Expr) = Any_Type then
1146 return;
1147
1148 elsif not Is_Static_Expression (Expr) then
1149 Flag_Non_Static_Expr
1150 ("small requires static expression!", Expr);
1151 return;
1152
1153 else
1154 Small := Expr_Value_R (Expr);
1155
1156 if Small <= Ureal_0 then
1157 Error_Msg_N ("small value must be greater than zero", Expr);
1158 return;
1159 end if;
1160
1161 end if;
1162
1163 if not Is_Ordinary_Fixed_Point_Type (U_Ent) then
1164 Error_Msg_N
1165 ("small requires an ordinary fixed point type", Nam);
1166
1167 elsif Has_Small_Clause (U_Ent) then
1168 Error_Msg_N ("small already given for &", Nam);
1169
1170 elsif Small > Delta_Value (U_Ent) then
1171 Error_Msg_N
1172 ("small value must not be greater then delta value", Nam);
1173
1174 else
1175 Set_Small_Value (U_Ent, Small);
1176 Set_Small_Value (Implicit_Base, Small);
1177 Set_Has_Small_Clause (U_Ent);
1178 Set_Has_Small_Clause (Implicit_Base);
1179 Set_Has_Non_Standard_Rep (Implicit_Base);
1180 end if;
1181 end Small;
1182
1183 ------------------
1184 -- Storage_Size --
1185 ------------------
1186
1187 -- Storage_Size attribute definition clause
1188
1189 when Attribute_Storage_Size => Storage_Size : declare
1190 Btype : constant Entity_Id := Base_Type (U_Ent);
1191 Sprag : Node_Id;
1192
1193 begin
1194 if Is_Task_Type (U_Ent) then
1195 Check_Restriction (No_Obsolescent_Features, N);
1196
1197 if Warn_On_Obsolescent_Feature then
1198 Error_Msg_N
1199 ("storage size clause for task is an " &
1200 "obsolescent feature ('R'M 'J.9)?", N);
1201 Error_Msg_N
1202 ("\use Storage_Size pragma instead?", N);
1203 end if;
1204
1205 FOnly := True;
1206 end if;
1207
1208 if not Is_Access_Type (U_Ent)
1209 and then Ekind (U_Ent) /= E_Task_Type
1210 then
1211 Error_Msg_N ("storage size cannot be given for &", Nam);
1212
1213 elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then
1214 Error_Msg_N
1215 ("storage size cannot be given for a derived access type",
1216 Nam);
1217
1218 elsif Has_Storage_Size_Clause (Btype) then
1219 Error_Msg_N ("storage size already given for &", Nam);
1220
1221 else
1222 Analyze_And_Resolve (Expr, Any_Integer);
1223
1224 if Is_Access_Type (U_Ent) then
1225
1226 if Present (Associated_Storage_Pool (U_Ent)) then
1227 Error_Msg_N ("storage pool already given for &", Nam);
1228 return;
1229 end if;
1230
1231 if Compile_Time_Known_Value (Expr)
1232 and then Expr_Value (Expr) = 0
1233 then
1234 Set_No_Pool_Assigned (Btype);
1235 end if;
1236
1237 else -- Is_Task_Type (U_Ent)
1238 Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size);
1239
1240 if Present (Sprag) then
1241 Error_Msg_Sloc := Sloc (Sprag);
1242 Error_Msg_N
1243 ("Storage_Size already specified#", Nam);
1244 return;
1245 end if;
1246 end if;
1247
1248 Set_Has_Storage_Size_Clause (Btype);
1249 end if;
1250 end Storage_Size;
1251
1252 ------------------
1253 -- Storage_Pool --
1254 ------------------
1255
1256 -- Storage_Pool attribute definition clause
1257
1258 when Attribute_Storage_Pool => Storage_Pool : declare
1259 Pool : Entity_Id;
1260 T : Entity_Id;
1261
1262 begin
1263 if Ekind (U_Ent) /= E_Access_Type
1264 and then Ekind (U_Ent) /= E_General_Access_Type
1265 then
1266 Error_Msg_N (
1267 "storage pool can only be given for access types", Nam);
1268 return;
1269
1270 elsif Is_Derived_Type (U_Ent) then
1271 Error_Msg_N
1272 ("storage pool cannot be given for a derived access type",
1273 Nam);
1274
1275 elsif Has_Storage_Size_Clause (U_Ent) then
1276 Error_Msg_N ("storage size already given for &", Nam);
1277 return;
1278
1279 elsif Present (Associated_Storage_Pool (U_Ent)) then
1280 Error_Msg_N ("storage pool already given for &", Nam);
1281 return;
1282 end if;
1283
1284 Analyze_And_Resolve
1285 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1286
1287 if Nkind (Expr) = N_Type_Conversion then
1288 T := Etype (Expression (Expr));
1289 else
1290 T := Etype (Expr);
1291 end if;
1292
1293 -- The Stack_Bounded_Pool is used internally for implementing
1294 -- access types with a Storage_Size. Since it only work
1295 -- properly when used on one specific type, we need to check
1296 -- that it is not highjacked improperly:
1297 -- type T is access Integer;
1298 -- for T'Storage_Size use n;
1299 -- type Q is access Float;
1300 -- for Q'Storage_Size use T'Storage_Size; -- incorrect
1301
1302 if Base_Type (T) = RTE (RE_Stack_Bounded_Pool) then
1303 Error_Msg_N ("non-sharable internal Pool", Expr);
1304 return;
1305 end if;
1306
1307 -- If the argument is a name that is not an entity name, then
1308 -- we construct a renaming operation to define an entity of
1309 -- type storage pool.
1310
1311 if not Is_Entity_Name (Expr)
1312 and then Is_Object_Reference (Expr)
1313 then
1314 Pool :=
1315 Make_Defining_Identifier (Loc,
1316 Chars => New_Internal_Name ('P'));
1317
1318 declare
1319 Rnode : constant Node_Id :=
1320 Make_Object_Renaming_Declaration (Loc,
1321 Defining_Identifier => Pool,
1322 Subtype_Mark =>
1323 New_Occurrence_Of (Etype (Expr), Loc),
1324 Name => Expr);
1325
1326 begin
1327 Insert_Before (N, Rnode);
1328 Analyze (Rnode);
1329 Set_Associated_Storage_Pool (U_Ent, Pool);
1330 end;
1331
1332 elsif Is_Entity_Name (Expr) then
1333 Pool := Entity (Expr);
1334
1335 -- If pool is a renamed object, get original one. This can
1336 -- happen with an explicit renaming, and within instances.
1337
1338 while Present (Renamed_Object (Pool))
1339 and then Is_Entity_Name (Renamed_Object (Pool))
1340 loop
1341 Pool := Entity (Renamed_Object (Pool));
1342 end loop;
1343
1344 if Present (Renamed_Object (Pool))
1345 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1346 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1347 then
1348 Pool := Entity (Expression (Renamed_Object (Pool)));
1349 end if;
1350
1351 Set_Associated_Storage_Pool (U_Ent, Pool);
1352
1353 elsif Nkind (Expr) = N_Type_Conversion
1354 and then Is_Entity_Name (Expression (Expr))
1355 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1356 then
1357 Pool := Entity (Expression (Expr));
1358 Set_Associated_Storage_Pool (U_Ent, Pool);
1359
1360 else
1361 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1362 return;
1363 end if;
1364 end Storage_Pool;
1365
1366 -----------------
1367 -- Stream_Size --
1368 -----------------
1369
1370 when Attribute_Stream_Size => Stream_Size : declare
1371 Size : constant Uint := Static_Integer (Expr);
1372
1373 begin
1374 if Has_Stream_Size_Clause (U_Ent) then
1375 Error_Msg_N ("Stream_Size already given for &", Nam);
1376
1377 elsif Is_Elementary_Type (U_Ent) then
1378 if Size /= System_Storage_Unit
1379 and then
1380 Size /= System_Storage_Unit * 2
1381 and then
1382 Size /= System_Storage_Unit * 4
1383 and then
1384 Size /= System_Storage_Unit * 8
1385 then
1386 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1387 Error_Msg_N
1388 ("stream size for elementary type must be a"
1389 & " power of 2 and at least ^", N);
1390
1391 elsif RM_Size (U_Ent) > Size then
1392 Error_Msg_Uint_1 := RM_Size (U_Ent);
1393 Error_Msg_N
1394 ("stream size for elementary type must be a"
1395 & " power of 2 and at least ^", N);
1396 end if;
1397
1398 Set_Has_Stream_Size_Clause (U_Ent);
1399
1400 else
1401 Error_Msg_N ("Stream_Size cannot be given for &", Nam);
1402 end if;
1403 end Stream_Size;
1404
1405 ----------------
1406 -- Value_Size --
1407 ----------------
1408
1409 -- Value_Size attribute definition clause
1410
1411 when Attribute_Value_Size => Value_Size : declare
1412 Size : constant Uint := Static_Integer (Expr);
1413 Biased : Boolean;
1414
1415 begin
1416 if not Is_Type (U_Ent) then
1417 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1418
1419 elsif Present
1420 (Get_Attribute_Definition_Clause
1421 (U_Ent, Attribute_Value_Size))
1422 then
1423 Error_Msg_N ("Value_Size already given for &", Nam);
1424
1425 else
1426 if Is_Elementary_Type (U_Ent) then
1427 Check_Size (Expr, U_Ent, Size, Biased);
1428 Set_Has_Biased_Representation (U_Ent, Biased);
1429 end if;
1430
1431 Set_RM_Size (U_Ent, Size);
1432 end if;
1433 end Value_Size;
1434
1435 -----------
1436 -- Write --
1437 -----------
1438
1439 -- Write attribute definition clause
1440 -- check for class-wide case will be performed later
1441
1442 when Attribute_Write => Write : declare
1443 Subp : Entity_Id := Empty;
1444 I : Interp_Index;
1445 It : Interp;
1446 Pnam : Entity_Id;
1447
1448 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
1449 -- Return true if the entity is a procedure with an
1450 -- appropriate profile for the write attribute.
1451
1452 ----------------------
1453 -- Has_Good_Profile --
1454 ----------------------
1455
1456 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
1457 F : Entity_Id;
1458 Ok : Boolean := False;
1459
1460 begin
1461 if Ekind (Subp) = E_Procedure then
1462 F := First_Formal (Subp);
1463
1464 if Present (F) then
1465 if Ekind (Etype (F)) = E_Anonymous_Access_Type
1466 and then
1467 Designated_Type (Etype (F)) =
1468 Class_Wide_Type (RTE (RE_Root_Stream_Type))
1469 then
1470 Next_Formal (F);
1471 Ok := Present (F)
1472 and then Parameter_Mode (F) = E_In_Parameter
1473 and then Base_Type (Etype (F)) = Base_Type (Ent)
1474 and then No (Next_Formal (F));
1475 end if;
1476 end if;
1477 end if;
1478
1479 return Ok;
1480 end Has_Good_Profile;
1481
1482 -- Start of processing for Write attribute definition
1483
1484 begin
1485 FOnly := True;
1486
1487 if not Is_Type (U_Ent) then
1488 Error_Msg_N ("local name must be a subtype", Nam);
1489 return;
1490 end if;
1491
1492 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Write);
1493
1494 if Present (Pnam)
1495 and then Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
1496 = Base_Type (U_Ent)
1497 then
1498 Error_Msg_Sloc := Sloc (Pnam);
1499 Error_Msg_N ("write attribute already defined #", Nam);
1500 return;
1501 end if;
1502
1503 Analyze (Expr);
1504
1505 if Is_Entity_Name (Expr) then
1506 if not Is_Overloaded (Expr) then
1507 if Has_Good_Profile (Entity (Expr)) then
1508 Subp := Entity (Expr);
1509 end if;
1510
1511 else
1512 Get_First_Interp (Expr, I, It);
1513
1514 while Present (It.Nam) loop
1515 if Has_Good_Profile (It.Nam) then
1516 Subp := It.Nam;
1517 exit;
1518 end if;
1519
1520 Get_Next_Interp (I, It);
1521 end loop;
1522 end if;
1523 end if;
1524
1525 if Present (Subp) then
1526 Set_Entity (Expr, Subp);
1527 Set_Etype (Expr, Etype (Subp));
1528 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Write);
1529 else
1530 Error_Msg_N ("incorrect expression for write attribute", Expr);
1531 return;
1532 end if;
1533 end Write;
1534
1535 -- All other attributes cannot be set
1536
1537 when others =>
1538 Error_Msg_N
1539 ("attribute& cannot be set with definition clause", N);
1540 end case;
1541
1542 -- The test for the type being frozen must be performed after
1543 -- any expression the clause has been analyzed since the expression
1544 -- itself might cause freezing that makes the clause illegal.
1545
1546 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1547 return;
1548 end if;
1549 end Analyze_Attribute_Definition_Clause;
1550
1551 ----------------------------
1552 -- Analyze_Code_Statement --
1553 ----------------------------
1554
1555 procedure Analyze_Code_Statement (N : Node_Id) is
1556 HSS : constant Node_Id := Parent (N);
1557 SBody : constant Node_Id := Parent (HSS);
1558 Subp : constant Entity_Id := Current_Scope;
1559 Stmt : Node_Id;
1560 Decl : Node_Id;
1561 StmtO : Node_Id;
1562 DeclO : Node_Id;
1563
1564 begin
1565 -- Analyze and check we get right type, note that this implements the
1566 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1567 -- is the only way that Asm_Insn could possibly be visible.
1568
1569 Analyze_And_Resolve (Expression (N));
1570
1571 if Etype (Expression (N)) = Any_Type then
1572 return;
1573 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1574 Error_Msg_N ("incorrect type for code statement", N);
1575 return;
1576 end if;
1577
1578 -- Make sure we appear in the handled statement sequence of a
1579 -- subprogram (RM 13.8(3)).
1580
1581 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1582 or else Nkind (SBody) /= N_Subprogram_Body
1583 then
1584 Error_Msg_N
1585 ("code statement can only appear in body of subprogram", N);
1586 return;
1587 end if;
1588
1589 -- Do remaining checks (RM 13.8(3)) if not already done
1590
1591 if not Is_Machine_Code_Subprogram (Subp) then
1592 Set_Is_Machine_Code_Subprogram (Subp);
1593
1594 -- No exception handlers allowed
1595
1596 if Present (Exception_Handlers (HSS)) then
1597 Error_Msg_N
1598 ("exception handlers not permitted in machine code subprogram",
1599 First (Exception_Handlers (HSS)));
1600 end if;
1601
1602 -- No declarations other than use clauses and pragmas (we allow
1603 -- certain internally generated declarations as well).
1604
1605 Decl := First (Declarations (SBody));
1606 while Present (Decl) loop
1607 DeclO := Original_Node (Decl);
1608 if Comes_From_Source (DeclO)
1609 and then Nkind (DeclO) /= N_Pragma
1610 and then Nkind (DeclO) /= N_Use_Package_Clause
1611 and then Nkind (DeclO) /= N_Use_Type_Clause
1612 and then Nkind (DeclO) /= N_Implicit_Label_Declaration
1613 then
1614 Error_Msg_N
1615 ("this declaration not allowed in machine code subprogram",
1616 DeclO);
1617 end if;
1618
1619 Next (Decl);
1620 end loop;
1621
1622 -- No statements other than code statements, pragmas, and labels.
1623 -- Again we allow certain internally generated statements.
1624
1625 Stmt := First (Statements (HSS));
1626 while Present (Stmt) loop
1627 StmtO := Original_Node (Stmt);
1628 if Comes_From_Source (StmtO)
1629 and then Nkind (StmtO) /= N_Pragma
1630 and then Nkind (StmtO) /= N_Label
1631 and then Nkind (StmtO) /= N_Code_Statement
1632 then
1633 Error_Msg_N
1634 ("this statement is not allowed in machine code subprogram",
1635 StmtO);
1636 end if;
1637
1638 Next (Stmt);
1639 end loop;
1640 end if;
1641 end Analyze_Code_Statement;
1642
1643 -----------------------------------------------
1644 -- Analyze_Enumeration_Representation_Clause --
1645 -----------------------------------------------
1646
1647 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1648 Ident : constant Node_Id := Identifier (N);
1649 Aggr : constant Node_Id := Array_Aggregate (N);
1650 Enumtype : Entity_Id;
1651 Elit : Entity_Id;
1652 Expr : Node_Id;
1653 Assoc : Node_Id;
1654 Choice : Node_Id;
1655 Val : Uint;
1656 Err : Boolean := False;
1657
1658 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1659 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1660 Min : Uint;
1661 Max : Uint;
1662
1663 begin
1664 -- First some basic error checks
1665
1666 Find_Type (Ident);
1667 Enumtype := Entity (Ident);
1668
1669 if Enumtype = Any_Type
1670 or else Rep_Item_Too_Early (Enumtype, N)
1671 then
1672 return;
1673 else
1674 Enumtype := Underlying_Type (Enumtype);
1675 end if;
1676
1677 if not Is_Enumeration_Type (Enumtype) then
1678 Error_Msg_NE
1679 ("enumeration type required, found}",
1680 Ident, First_Subtype (Enumtype));
1681 return;
1682 end if;
1683
1684 -- Ignore rep clause on generic actual type. This will already have
1685 -- been flagged on the template as an error, and this is the safest
1686 -- way to ensure we don't get a junk cascaded message in the instance.
1687
1688 if Is_Generic_Actual_Type (Enumtype) then
1689 return;
1690
1691 -- Type must be in current scope
1692
1693 elsif Scope (Enumtype) /= Current_Scope then
1694 Error_Msg_N ("type must be declared in this scope", Ident);
1695 return;
1696
1697 -- Type must be a first subtype
1698
1699 elsif not Is_First_Subtype (Enumtype) then
1700 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1701 return;
1702
1703 -- Ignore duplicate rep clause
1704
1705 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1706 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1707 return;
1708
1709 -- Don't allow rep clause for standard [wide_[wide_]]character
1710
1711 elsif Root_Type (Enumtype) = Standard_Character
1712 or else Root_Type (Enumtype) = Standard_Wide_Character
1713 or else Root_Type (Enumtype) = Standard_Wide_Wide_Character
1714 then
1715 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1716 return;
1717
1718 -- All tests passed, so set rep clause in place
1719
1720 else
1721 Set_Has_Enumeration_Rep_Clause (Enumtype);
1722 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
1723 end if;
1724
1725 -- Now we process the aggregate. Note that we don't use the normal
1726 -- aggregate code for this purpose, because we don't want any of the
1727 -- normal expansion activities, and a number of special semantic
1728 -- rules apply (including the component type being any integer type)
1729
1730 -- Badent signals that we found some incorrect entries processing
1731 -- the list. The final checks for completeness and ordering are
1732 -- skipped in this case.
1733
1734 Elit := First_Literal (Enumtype);
1735
1736 -- First the positional entries if any
1737
1738 if Present (Expressions (Aggr)) then
1739 Expr := First (Expressions (Aggr));
1740 while Present (Expr) loop
1741 if No (Elit) then
1742 Error_Msg_N ("too many entries in aggregate", Expr);
1743 return;
1744 end if;
1745
1746 Val := Static_Integer (Expr);
1747
1748 if Val = No_Uint then
1749 Err := True;
1750
1751 elsif Val < Lo or else Hi < Val then
1752 Error_Msg_N ("value outside permitted range", Expr);
1753 Err := True;
1754 end if;
1755
1756 Set_Enumeration_Rep (Elit, Val);
1757 Set_Enumeration_Rep_Expr (Elit, Expr);
1758 Next (Expr);
1759 Next (Elit);
1760 end loop;
1761 end if;
1762
1763 -- Now process the named entries if present
1764
1765 if Present (Component_Associations (Aggr)) then
1766 Assoc := First (Component_Associations (Aggr));
1767 while Present (Assoc) loop
1768 Choice := First (Choices (Assoc));
1769
1770 if Present (Next (Choice)) then
1771 Error_Msg_N
1772 ("multiple choice not allowed here", Next (Choice));
1773 Err := True;
1774 end if;
1775
1776 if Nkind (Choice) = N_Others_Choice then
1777 Error_Msg_N ("others choice not allowed here", Choice);
1778 Err := True;
1779
1780 elsif Nkind (Choice) = N_Range then
1781 -- ??? should allow zero/one element range here
1782 Error_Msg_N ("range not allowed here", Choice);
1783 Err := True;
1784
1785 else
1786 Analyze_And_Resolve (Choice, Enumtype);
1787
1788 if Is_Entity_Name (Choice)
1789 and then Is_Type (Entity (Choice))
1790 then
1791 Error_Msg_N ("subtype name not allowed here", Choice);
1792 Err := True;
1793 -- ??? should allow static subtype with zero/one entry
1794
1795 elsif Etype (Choice) = Base_Type (Enumtype) then
1796 if not Is_Static_Expression (Choice) then
1797 Flag_Non_Static_Expr
1798 ("non-static expression used for choice!", Choice);
1799 Err := True;
1800
1801 else
1802 Elit := Expr_Value_E (Choice);
1803
1804 if Present (Enumeration_Rep_Expr (Elit)) then
1805 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
1806 Error_Msg_NE
1807 ("representation for& previously given#",
1808 Choice, Elit);
1809 Err := True;
1810 end if;
1811
1812 Set_Enumeration_Rep_Expr (Elit, Choice);
1813
1814 Expr := Expression (Assoc);
1815 Val := Static_Integer (Expr);
1816
1817 if Val = No_Uint then
1818 Err := True;
1819
1820 elsif Val < Lo or else Hi < Val then
1821 Error_Msg_N ("value outside permitted range", Expr);
1822 Err := True;
1823 end if;
1824
1825 Set_Enumeration_Rep (Elit, Val);
1826 end if;
1827 end if;
1828 end if;
1829
1830 Next (Assoc);
1831 end loop;
1832 end if;
1833
1834 -- Aggregate is fully processed. Now we check that a full set of
1835 -- representations was given, and that they are in range and in order.
1836 -- These checks are only done if no other errors occurred.
1837
1838 if not Err then
1839 Min := No_Uint;
1840 Max := No_Uint;
1841
1842 Elit := First_Literal (Enumtype);
1843 while Present (Elit) loop
1844 if No (Enumeration_Rep_Expr (Elit)) then
1845 Error_Msg_NE ("missing representation for&!", N, Elit);
1846
1847 else
1848 Val := Enumeration_Rep (Elit);
1849
1850 if Min = No_Uint then
1851 Min := Val;
1852 end if;
1853
1854 if Val /= No_Uint then
1855 if Max /= No_Uint and then Val <= Max then
1856 Error_Msg_NE
1857 ("enumeration value for& not ordered!",
1858 Enumeration_Rep_Expr (Elit), Elit);
1859 end if;
1860
1861 Max := Val;
1862 end if;
1863
1864 -- If there is at least one literal whose representation
1865 -- is not equal to the Pos value, then note that this
1866 -- enumeration type has a non-standard representation.
1867
1868 if Val /= Enumeration_Pos (Elit) then
1869 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
1870 end if;
1871 end if;
1872
1873 Next (Elit);
1874 end loop;
1875
1876 -- Now set proper size information
1877
1878 declare
1879 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
1880
1881 begin
1882 if Has_Size_Clause (Enumtype) then
1883 if Esize (Enumtype) >= Minsize then
1884 null;
1885
1886 else
1887 Minsize :=
1888 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
1889
1890 if Esize (Enumtype) < Minsize then
1891 Error_Msg_N ("previously given size is too small", N);
1892
1893 else
1894 Set_Has_Biased_Representation (Enumtype);
1895 end if;
1896 end if;
1897
1898 else
1899 Set_RM_Size (Enumtype, Minsize);
1900 Set_Enum_Esize (Enumtype);
1901 end if;
1902
1903 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
1904 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
1905 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
1906 end;
1907 end if;
1908
1909 -- We repeat the too late test in case it froze itself!
1910
1911 if Rep_Item_Too_Late (Enumtype, N) then
1912 null;
1913 end if;
1914 end Analyze_Enumeration_Representation_Clause;
1915
1916 ----------------------------
1917 -- Analyze_Free_Statement --
1918 ----------------------------
1919
1920 procedure Analyze_Free_Statement (N : Node_Id) is
1921 begin
1922 Analyze (Expression (N));
1923 end Analyze_Free_Statement;
1924
1925 ------------------------------------------
1926 -- Analyze_Record_Representation_Clause --
1927 ------------------------------------------
1928
1929 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
1930 Loc : constant Source_Ptr := Sloc (N);
1931 Ident : constant Node_Id := Identifier (N);
1932 Rectype : Entity_Id;
1933 Fent : Entity_Id;
1934 CC : Node_Id;
1935 Posit : Uint;
1936 Fbit : Uint;
1937 Lbit : Uint;
1938 Hbit : Uint := Uint_0;
1939 Comp : Entity_Id;
1940 Ocomp : Entity_Id;
1941 Biased : Boolean;
1942
1943 Max_Bit_So_Far : Uint;
1944 -- Records the maximum bit position so far. If all field positions
1945 -- are monotonically increasing, then we can skip the circuit for
1946 -- checking for overlap, since no overlap is possible.
1947
1948 Overlap_Check_Required : Boolean;
1949 -- Used to keep track of whether or not an overlap check is required
1950
1951 Ccount : Natural := 0;
1952 -- Number of component clauses in record rep clause
1953
1954 begin
1955 Find_Type (Ident);
1956 Rectype := Entity (Ident);
1957
1958 if Rectype = Any_Type
1959 or else Rep_Item_Too_Early (Rectype, N)
1960 then
1961 return;
1962 else
1963 Rectype := Underlying_Type (Rectype);
1964 end if;
1965
1966 -- First some basic error checks
1967
1968 if not Is_Record_Type (Rectype) then
1969 Error_Msg_NE
1970 ("record type required, found}", Ident, First_Subtype (Rectype));
1971 return;
1972
1973 elsif Is_Unchecked_Union (Rectype) then
1974 Error_Msg_N
1975 ("record rep clause not allowed for Unchecked_Union", N);
1976
1977 elsif Scope (Rectype) /= Current_Scope then
1978 Error_Msg_N ("type must be declared in this scope", N);
1979 return;
1980
1981 elsif not Is_First_Subtype (Rectype) then
1982 Error_Msg_N ("cannot give record rep clause for subtype", N);
1983 return;
1984
1985 elsif Has_Record_Rep_Clause (Rectype) then
1986 Error_Msg_N ("duplicate record rep clause ignored", N);
1987 return;
1988
1989 elsif Rep_Item_Too_Late (Rectype, N) then
1990 return;
1991 end if;
1992
1993 if Present (Mod_Clause (N)) then
1994 declare
1995 Loc : constant Source_Ptr := Sloc (N);
1996 M : constant Node_Id := Mod_Clause (N);
1997 P : constant List_Id := Pragmas_Before (M);
1998 AtM_Nod : Node_Id;
1999
2000 Mod_Val : Uint;
2001 pragma Warnings (Off, Mod_Val);
2002
2003 begin
2004 Check_Restriction (No_Obsolescent_Features, Mod_Clause (N));
2005
2006 if Warn_On_Obsolescent_Feature then
2007 Error_Msg_N
2008 ("mod clause is an obsolescent feature ('R'M 'J.8)?", N);
2009 Error_Msg_N
2010 ("\use alignment attribute definition clause instead?", N);
2011 end if;
2012
2013 if Present (P) then
2014 Analyze_List (P);
2015 end if;
2016
2017 -- In ASIS_Mode mode, expansion is disabled, but we must
2018 -- convert the Mod clause into an alignment clause anyway, so
2019 -- that the back-end can compute and back-annotate properly the
2020 -- size and alignment of types that may include this record.
2021
2022 if Operating_Mode = Check_Semantics
2023 and then ASIS_Mode
2024 then
2025 AtM_Nod :=
2026 Make_Attribute_Definition_Clause (Loc,
2027 Name => New_Reference_To (Base_Type (Rectype), Loc),
2028 Chars => Name_Alignment,
2029 Expression => Relocate_Node (Expression (M)));
2030
2031 Set_From_At_Mod (AtM_Nod);
2032 Insert_After (N, AtM_Nod);
2033 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
2034 Set_Mod_Clause (N, Empty);
2035
2036 else
2037 -- Get the alignment value to perform error checking
2038
2039 Mod_Val := Get_Alignment_Value (Expression (M));
2040
2041 end if;
2042 end;
2043 end if;
2044
2045 -- Clear any existing component clauses for the type (this happens
2046 -- with derived types, where we are now overriding the original)
2047
2048 Fent := First_Entity (Rectype);
2049
2050 Comp := Fent;
2051 while Present (Comp) loop
2052 if Ekind (Comp) = E_Component
2053 or else Ekind (Comp) = E_Discriminant
2054 then
2055 Set_Component_Clause (Comp, Empty);
2056 end if;
2057
2058 Next_Entity (Comp);
2059 end loop;
2060
2061 -- All done if no component clauses
2062
2063 CC := First (Component_Clauses (N));
2064
2065 if No (CC) then
2066 return;
2067 end if;
2068
2069 -- If a tag is present, then create a component clause that places
2070 -- it at the start of the record (otherwise gigi may place it after
2071 -- other fields that have rep clauses).
2072
2073 if Nkind (Fent) = N_Defining_Identifier
2074 and then Chars (Fent) = Name_uTag
2075 then
2076 Set_Component_Bit_Offset (Fent, Uint_0);
2077 Set_Normalized_Position (Fent, Uint_0);
2078 Set_Normalized_First_Bit (Fent, Uint_0);
2079 Set_Normalized_Position_Max (Fent, Uint_0);
2080 Init_Esize (Fent, System_Address_Size);
2081
2082 Set_Component_Clause (Fent,
2083 Make_Component_Clause (Loc,
2084 Component_Name =>
2085 Make_Identifier (Loc,
2086 Chars => Name_uTag),
2087
2088 Position =>
2089 Make_Integer_Literal (Loc,
2090 Intval => Uint_0),
2091
2092 First_Bit =>
2093 Make_Integer_Literal (Loc,
2094 Intval => Uint_0),
2095
2096 Last_Bit =>
2097 Make_Integer_Literal (Loc,
2098 UI_From_Int (System_Address_Size))));
2099
2100 Ccount := Ccount + 1;
2101 end if;
2102
2103 -- A representation like this applies to the base type
2104
2105 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2106 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2107 Set_Has_Specified_Layout (Base_Type (Rectype));
2108
2109 Max_Bit_So_Far := Uint_Minus_1;
2110 Overlap_Check_Required := False;
2111
2112 -- Process the component clauses
2113
2114 while Present (CC) loop
2115
2116 -- If pragma, just analyze it
2117
2118 if Nkind (CC) = N_Pragma then
2119 Analyze (CC);
2120
2121 -- Processing for real component clause
2122
2123 else
2124 Ccount := Ccount + 1;
2125 Posit := Static_Integer (Position (CC));
2126 Fbit := Static_Integer (First_Bit (CC));
2127 Lbit := Static_Integer (Last_Bit (CC));
2128
2129 if Posit /= No_Uint
2130 and then Fbit /= No_Uint
2131 and then Lbit /= No_Uint
2132 then
2133 if Posit < 0 then
2134 Error_Msg_N
2135 ("position cannot be negative", Position (CC));
2136
2137 elsif Fbit < 0 then
2138 Error_Msg_N
2139 ("first bit cannot be negative", First_Bit (CC));
2140
2141 -- Values look OK, so find the corresponding record component
2142 -- Even though the syntax allows an attribute reference for
2143 -- implementation-defined components, GNAT does not allow the
2144 -- tag to get an explicit position.
2145
2146 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2147 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2148 Error_Msg_N ("position of tag cannot be specified", CC);
2149 else
2150 Error_Msg_N ("illegal component name", CC);
2151 end if;
2152
2153 else
2154 Comp := First_Entity (Rectype);
2155 while Present (Comp) loop
2156 exit when Chars (Comp) = Chars (Component_Name (CC));
2157 Next_Entity (Comp);
2158 end loop;
2159
2160 if No (Comp) then
2161
2162 -- Maybe component of base type that is absent from
2163 -- statically constrained first subtype.
2164
2165 Comp := First_Entity (Base_Type (Rectype));
2166 while Present (Comp) loop
2167 exit when Chars (Comp) = Chars (Component_Name (CC));
2168 Next_Entity (Comp);
2169 end loop;
2170 end if;
2171
2172 if No (Comp) then
2173 Error_Msg_N
2174 ("component clause is for non-existent field", CC);
2175
2176 elsif Present (Component_Clause (Comp)) then
2177 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2178 Error_Msg_N
2179 ("component clause previously given#", CC);
2180
2181 else
2182 -- Update Fbit and Lbit to the actual bit number
2183
2184 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2185 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2186
2187 if Fbit <= Max_Bit_So_Far then
2188 Overlap_Check_Required := True;
2189 else
2190 Max_Bit_So_Far := Lbit;
2191 end if;
2192
2193 if Has_Size_Clause (Rectype)
2194 and then Esize (Rectype) <= Lbit
2195 then
2196 Error_Msg_N
2197 ("bit number out of range of specified size",
2198 Last_Bit (CC));
2199 else
2200 Set_Component_Clause (Comp, CC);
2201 Set_Component_Bit_Offset (Comp, Fbit);
2202 Set_Esize (Comp, 1 + (Lbit - Fbit));
2203 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2204 Set_Normalized_Position (Comp, Fbit / SSU);
2205
2206 Set_Normalized_Position_Max
2207 (Fent, Normalized_Position (Fent));
2208
2209 if Is_Tagged_Type (Rectype)
2210 and then Fbit < System_Address_Size
2211 then
2212 Error_Msg_NE
2213 ("component overlaps tag field of&",
2214 CC, Rectype);
2215 end if;
2216
2217 -- This information is also set in the corresponding
2218 -- component of the base type, found by accessing the
2219 -- Original_Record_Component link if it is present.
2220
2221 Ocomp := Original_Record_Component (Comp);
2222
2223 if Hbit < Lbit then
2224 Hbit := Lbit;
2225 end if;
2226
2227 Check_Size
2228 (Component_Name (CC),
2229 Etype (Comp),
2230 Esize (Comp),
2231 Biased);
2232
2233 Set_Has_Biased_Representation (Comp, Biased);
2234
2235 if Present (Ocomp) then
2236 Set_Component_Clause (Ocomp, CC);
2237 Set_Component_Bit_Offset (Ocomp, Fbit);
2238 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2239 Set_Normalized_Position (Ocomp, Fbit / SSU);
2240 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2241
2242 Set_Normalized_Position_Max
2243 (Ocomp, Normalized_Position (Ocomp));
2244
2245 Set_Has_Biased_Representation
2246 (Ocomp, Has_Biased_Representation (Comp));
2247 end if;
2248
2249 if Esize (Comp) < 0 then
2250 Error_Msg_N ("component size is negative", CC);
2251 end if;
2252 end if;
2253 end if;
2254 end if;
2255 end if;
2256 end if;
2257
2258 Next (CC);
2259 end loop;
2260
2261 -- Now that we have processed all the component clauses, check for
2262 -- overlap. We have to leave this till last, since the components
2263 -- can appear in any arbitrary order in the representation clause.
2264
2265 -- We do not need this check if all specified ranges were monotonic,
2266 -- as recorded by Overlap_Check_Required being False at this stage.
2267
2268 -- This first section checks if there are any overlapping entries
2269 -- at all. It does this by sorting all entries and then seeing if
2270 -- there are any overlaps. If there are none, then that is decisive,
2271 -- but if there are overlaps, they may still be OK (they may result
2272 -- from fields in different variants).
2273
2274 if Overlap_Check_Required then
2275 Overlap_Check1 : declare
2276
2277 OC_Fbit : array (0 .. Ccount) of Uint;
2278 -- First-bit values for component clauses, the value is the
2279 -- offset of the first bit of the field from start of record.
2280 -- The zero entry is for use in sorting.
2281
2282 OC_Lbit : array (0 .. Ccount) of Uint;
2283 -- Last-bit values for component clauses, the value is the
2284 -- offset of the last bit of the field from start of record.
2285 -- The zero entry is for use in sorting.
2286
2287 OC_Count : Natural := 0;
2288 -- Count of entries in OC_Fbit and OC_Lbit
2289
2290 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2291 -- Compare routine for Sort (See GNAT.Heap_Sort_A)
2292
2293 procedure OC_Move (From : Natural; To : Natural);
2294 -- Move routine for Sort (see GNAT.Heap_Sort_A)
2295
2296 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2297 begin
2298 return OC_Fbit (Op1) < OC_Fbit (Op2);
2299 end OC_Lt;
2300
2301 procedure OC_Move (From : Natural; To : Natural) is
2302 begin
2303 OC_Fbit (To) := OC_Fbit (From);
2304 OC_Lbit (To) := OC_Lbit (From);
2305 end OC_Move;
2306
2307 begin
2308 CC := First (Component_Clauses (N));
2309 while Present (CC) loop
2310 if Nkind (CC) /= N_Pragma then
2311 Posit := Static_Integer (Position (CC));
2312 Fbit := Static_Integer (First_Bit (CC));
2313 Lbit := Static_Integer (Last_Bit (CC));
2314
2315 if Posit /= No_Uint
2316 and then Fbit /= No_Uint
2317 and then Lbit /= No_Uint
2318 then
2319 OC_Count := OC_Count + 1;
2320 Posit := Posit * SSU;
2321 OC_Fbit (OC_Count) := Fbit + Posit;
2322 OC_Lbit (OC_Count) := Lbit + Posit;
2323 end if;
2324 end if;
2325
2326 Next (CC);
2327 end loop;
2328
2329 Sort
2330 (OC_Count,
2331 OC_Move'Unrestricted_Access,
2332 OC_Lt'Unrestricted_Access);
2333
2334 Overlap_Check_Required := False;
2335 for J in 1 .. OC_Count - 1 loop
2336 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2337 Overlap_Check_Required := True;
2338 exit;
2339 end if;
2340 end loop;
2341 end Overlap_Check1;
2342 end if;
2343
2344 -- If Overlap_Check_Required is still True, then we have to do
2345 -- the full scale overlap check, since we have at least two fields
2346 -- that do overlap, and we need to know if that is OK since they
2347 -- are in the same variant, or whether we have a definite problem
2348
2349 if Overlap_Check_Required then
2350 Overlap_Check2 : declare
2351 C1_Ent, C2_Ent : Entity_Id;
2352 -- Entities of components being checked for overlap
2353
2354 Clist : Node_Id;
2355 -- Component_List node whose Component_Items are being checked
2356
2357 Citem : Node_Id;
2358 -- Component declaration for component being checked
2359
2360 begin
2361 C1_Ent := First_Entity (Base_Type (Rectype));
2362
2363 -- Loop through all components in record. For each component check
2364 -- for overlap with any of the preceding elements on the component
2365 -- list containing the component, and also, if the component is in
2366 -- a variant, check against components outside the case structure.
2367 -- This latter test is repeated recursively up the variant tree.
2368
2369 Main_Component_Loop : while Present (C1_Ent) loop
2370 if Ekind (C1_Ent) /= E_Component
2371 and then Ekind (C1_Ent) /= E_Discriminant
2372 then
2373 goto Continue_Main_Component_Loop;
2374 end if;
2375
2376 -- Skip overlap check if entity has no declaration node. This
2377 -- happens with discriminants in constrained derived types.
2378 -- Probably we are missing some checks as a result, but that
2379 -- does not seem terribly serious ???
2380
2381 if No (Declaration_Node (C1_Ent)) then
2382 goto Continue_Main_Component_Loop;
2383 end if;
2384
2385 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2386
2387 -- Loop through component lists that need checking. Check the
2388 -- current component list and all lists in variants above us.
2389
2390 Component_List_Loop : loop
2391
2392 -- If derived type definition, go to full declaration
2393 -- If at outer level, check discriminants if there are any
2394
2395 if Nkind (Clist) = N_Derived_Type_Definition then
2396 Clist := Parent (Clist);
2397 end if;
2398
2399 -- Outer level of record definition, check discriminants
2400
2401 if Nkind (Clist) = N_Full_Type_Declaration
2402 or else Nkind (Clist) = N_Private_Type_Declaration
2403 then
2404 if Has_Discriminants (Defining_Identifier (Clist)) then
2405 C2_Ent :=
2406 First_Discriminant (Defining_Identifier (Clist));
2407
2408 while Present (C2_Ent) loop
2409 exit when C1_Ent = C2_Ent;
2410 Check_Component_Overlap (C1_Ent, C2_Ent);
2411 Next_Discriminant (C2_Ent);
2412 end loop;
2413 end if;
2414
2415 -- Record extension case
2416
2417 elsif Nkind (Clist) = N_Derived_Type_Definition then
2418 Clist := Empty;
2419
2420 -- Otherwise check one component list
2421
2422 else
2423 Citem := First (Component_Items (Clist));
2424
2425 while Present (Citem) loop
2426 if Nkind (Citem) = N_Component_Declaration then
2427 C2_Ent := Defining_Identifier (Citem);
2428 exit when C1_Ent = C2_Ent;
2429 Check_Component_Overlap (C1_Ent, C2_Ent);
2430 end if;
2431
2432 Next (Citem);
2433 end loop;
2434 end if;
2435
2436 -- Check for variants above us (the parent of the Clist can
2437 -- be a variant, in which case its parent is a variant part,
2438 -- and the parent of the variant part is a component list
2439 -- whose components must all be checked against the current
2440 -- component for overlap.
2441
2442 if Nkind (Parent (Clist)) = N_Variant then
2443 Clist := Parent (Parent (Parent (Clist)));
2444
2445 -- Check for possible discriminant part in record, this is
2446 -- treated essentially as another level in the recursion.
2447 -- For this case we have the parent of the component list
2448 -- is the record definition, and its parent is the full
2449 -- type declaration which contains the discriminant
2450 -- specifications.
2451
2452 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2453 Clist := Parent (Parent ((Clist)));
2454
2455 -- If neither of these two cases, we are at the top of
2456 -- the tree
2457
2458 else
2459 exit Component_List_Loop;
2460 end if;
2461 end loop Component_List_Loop;
2462
2463 <<Continue_Main_Component_Loop>>
2464 Next_Entity (C1_Ent);
2465
2466 end loop Main_Component_Loop;
2467 end Overlap_Check2;
2468 end if;
2469
2470 -- For records that have component clauses for all components, and
2471 -- whose size is less than or equal to 32, we need to know the size
2472 -- in the front end to activate possible packed array processing
2473 -- where the component type is a record.
2474
2475 -- At this stage Hbit + 1 represents the first unused bit from all
2476 -- the component clauses processed, so if the component clauses are
2477 -- complete, then this is the length of the record.
2478
2479 -- For records longer than System.Storage_Unit, and for those where
2480 -- not all components have component clauses, the back end determines
2481 -- the length (it may for example be appopriate to round up the size
2482 -- to some convenient boundary, based on alignment considerations etc).
2483
2484 if Unknown_RM_Size (Rectype)
2485 and then Hbit + 1 <= 32
2486 then
2487 -- Nothing to do if at least one component with no component clause
2488
2489 Comp := First_Entity (Rectype);
2490 while Present (Comp) loop
2491 if Ekind (Comp) = E_Component
2492 or else Ekind (Comp) = E_Discriminant
2493 then
2494 if No (Component_Clause (Comp)) then
2495 return;
2496 end if;
2497 end if;
2498
2499 Next_Entity (Comp);
2500 end loop;
2501
2502 -- If we fall out of loop, all components have component clauses
2503 -- and so we can set the size to the maximum value.
2504
2505 Set_RM_Size (Rectype, Hbit + 1);
2506 end if;
2507 end Analyze_Record_Representation_Clause;
2508
2509 -----------------------------
2510 -- Check_Component_Overlap --
2511 -----------------------------
2512
2513 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
2514 begin
2515 if Present (Component_Clause (C1_Ent))
2516 and then Present (Component_Clause (C2_Ent))
2517 then
2518 -- Exclude odd case where we have two tag fields in the same
2519 -- record, both at location zero. This seems a bit strange,
2520 -- but it seems to happen in some circumstances ???
2521
2522 if Chars (C1_Ent) = Name_uTag
2523 and then Chars (C2_Ent) = Name_uTag
2524 then
2525 return;
2526 end if;
2527
2528 -- Here we check if the two fields overlap
2529
2530 declare
2531 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
2532 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
2533 E1 : constant Uint := S1 + Esize (C1_Ent);
2534 E2 : constant Uint := S2 + Esize (C2_Ent);
2535
2536 begin
2537 if E2 <= S1 or else E1 <= S2 then
2538 null;
2539 else
2540 Error_Msg_Node_2 :=
2541 Component_Name (Component_Clause (C2_Ent));
2542 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
2543 Error_Msg_Node_1 :=
2544 Component_Name (Component_Clause (C1_Ent));
2545 Error_Msg_N
2546 ("component& overlaps & #",
2547 Component_Name (Component_Clause (C1_Ent)));
2548 end if;
2549 end;
2550 end if;
2551 end Check_Component_Overlap;
2552
2553 -----------------------------------
2554 -- Check_Constant_Address_Clause --
2555 -----------------------------------
2556
2557 procedure Check_Constant_Address_Clause
2558 (Expr : Node_Id;
2559 U_Ent : Entity_Id)
2560 is
2561 procedure Check_At_Constant_Address (Nod : Node_Id);
2562 -- Checks that the given node N represents a name whose 'Address
2563 -- is constant (in the same sense as OK_Constant_Address_Clause,
2564 -- i.e. the address value is the same at the point of declaration
2565 -- of U_Ent and at the time of elaboration of the address clause.
2566
2567 procedure Check_Expr_Constants (Nod : Node_Id);
2568 -- Checks that Nod meets the requirements for a constant address
2569 -- clause in the sense of the enclosing procedure.
2570
2571 procedure Check_List_Constants (Lst : List_Id);
2572 -- Check that all elements of list Lst meet the requirements for a
2573 -- constant address clause in the sense of the enclosing procedure.
2574
2575 -------------------------------
2576 -- Check_At_Constant_Address --
2577 -------------------------------
2578
2579 procedure Check_At_Constant_Address (Nod : Node_Id) is
2580 begin
2581 if Is_Entity_Name (Nod) then
2582 if Present (Address_Clause (Entity ((Nod)))) then
2583 Error_Msg_NE
2584 ("invalid address clause for initialized object &!",
2585 Nod, U_Ent);
2586 Error_Msg_NE
2587 ("address for& cannot" &
2588 " depend on another address clause! ('R'M 13.1(22))!",
2589 Nod, U_Ent);
2590
2591 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
2592 and then Sloc (U_Ent) < Sloc (Entity (Nod))
2593 then
2594 Error_Msg_NE
2595 ("invalid address clause for initialized object &!",
2596 Nod, U_Ent);
2597 Error_Msg_Name_1 := Chars (Entity (Nod));
2598 Error_Msg_Name_2 := Chars (U_Ent);
2599 Error_Msg_N
2600 ("\% must be defined before % ('R'M 13.1(22))!",
2601 Nod);
2602 end if;
2603
2604 elsif Nkind (Nod) = N_Selected_Component then
2605 declare
2606 T : constant Entity_Id := Etype (Prefix (Nod));
2607
2608 begin
2609 if (Is_Record_Type (T)
2610 and then Has_Discriminants (T))
2611 or else
2612 (Is_Access_Type (T)
2613 and then Is_Record_Type (Designated_Type (T))
2614 and then Has_Discriminants (Designated_Type (T)))
2615 then
2616 Error_Msg_NE
2617 ("invalid address clause for initialized object &!",
2618 Nod, U_Ent);
2619 Error_Msg_N
2620 ("\address cannot depend on component" &
2621 " of discriminated record ('R'M 13.1(22))!",
2622 Nod);
2623 else
2624 Check_At_Constant_Address (Prefix (Nod));
2625 end if;
2626 end;
2627
2628 elsif Nkind (Nod) = N_Indexed_Component then
2629 Check_At_Constant_Address (Prefix (Nod));
2630 Check_List_Constants (Expressions (Nod));
2631
2632 else
2633 Check_Expr_Constants (Nod);
2634 end if;
2635 end Check_At_Constant_Address;
2636
2637 --------------------------
2638 -- Check_Expr_Constants --
2639 --------------------------
2640
2641 procedure Check_Expr_Constants (Nod : Node_Id) is
2642 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
2643 Ent : Entity_Id := Empty;
2644
2645 begin
2646 if Nkind (Nod) in N_Has_Etype
2647 and then Etype (Nod) = Any_Type
2648 then
2649 return;
2650 end if;
2651
2652 case Nkind (Nod) is
2653 when N_Empty | N_Error =>
2654 return;
2655
2656 when N_Identifier | N_Expanded_Name =>
2657 Ent := Entity (Nod);
2658
2659 -- We need to look at the original node if it is different
2660 -- from the node, since we may have rewritten things and
2661 -- substituted an identifier representing the rewrite.
2662
2663 if Original_Node (Nod) /= Nod then
2664 Check_Expr_Constants (Original_Node (Nod));
2665
2666 -- If the node is an object declaration without initial
2667 -- value, some code has been expanded, and the expression
2668 -- is not constant, even if the constituents might be
2669 -- acceptable, as in A'Address + offset.
2670
2671 if Ekind (Ent) = E_Variable
2672 and then Nkind (Declaration_Node (Ent))
2673 = N_Object_Declaration
2674 and then
2675 No (Expression (Declaration_Node (Ent)))
2676 then
2677 Error_Msg_NE
2678 ("invalid address clause for initialized object &!",
2679 Nod, U_Ent);
2680
2681 -- If entity is constant, it may be the result of expanding
2682 -- a check. We must verify that its declaration appears
2683 -- before the object in question, else we also reject the
2684 -- address clause.
2685
2686 elsif Ekind (Ent) = E_Constant
2687 and then In_Same_Source_Unit (Ent, U_Ent)
2688 and then Sloc (Ent) > Loc_U_Ent
2689 then
2690 Error_Msg_NE
2691 ("invalid address clause for initialized object &!",
2692 Nod, U_Ent);
2693 end if;
2694
2695 return;
2696 end if;
2697
2698 -- Otherwise look at the identifier and see if it is OK
2699
2700 if Ekind (Ent) = E_Named_Integer
2701 or else
2702 Ekind (Ent) = E_Named_Real
2703 or else
2704 Is_Type (Ent)
2705 then
2706 return;
2707
2708 elsif
2709 Ekind (Ent) = E_Constant
2710 or else
2711 Ekind (Ent) = E_In_Parameter
2712 then
2713 -- This is the case where we must have Ent defined
2714 -- before U_Ent. Clearly if they are in different
2715 -- units this requirement is met since the unit
2716 -- containing Ent is already processed.
2717
2718 if not In_Same_Source_Unit (Ent, U_Ent) then
2719 return;
2720
2721 -- Otherwise location of Ent must be before the
2722 -- location of U_Ent, that's what prior defined means.
2723
2724 elsif Sloc (Ent) < Loc_U_Ent then
2725 return;
2726
2727 else
2728 Error_Msg_NE
2729 ("invalid address clause for initialized object &!",
2730 Nod, U_Ent);
2731 Error_Msg_Name_1 := Chars (Ent);
2732 Error_Msg_Name_2 := Chars (U_Ent);
2733 Error_Msg_N
2734 ("\% must be defined before % ('R'M 13.1(22))!",
2735 Nod);
2736 end if;
2737
2738 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
2739 Check_Expr_Constants (Original_Node (Nod));
2740
2741 else
2742 Error_Msg_NE
2743 ("invalid address clause for initialized object &!",
2744 Nod, U_Ent);
2745
2746 if Comes_From_Source (Ent) then
2747 Error_Msg_Name_1 := Chars (Ent);
2748 Error_Msg_N
2749 ("\reference to variable% not allowed"
2750 & " ('R'M 13.1(22))!", Nod);
2751 else
2752 Error_Msg_N
2753 ("non-static expression not allowed"
2754 & " ('R'M 13.1(22))!", Nod);
2755 end if;
2756 end if;
2757
2758 when N_Integer_Literal =>
2759
2760 -- If this is a rewritten unchecked conversion, in a system
2761 -- where Address is an integer type, always use the base type
2762 -- for a literal value. This is user-friendly and prevents
2763 -- order-of-elaboration issues with instances of unchecked
2764 -- conversion.
2765
2766 if Nkind (Original_Node (Nod)) = N_Function_Call then
2767 Set_Etype (Nod, Base_Type (Etype (Nod)));
2768 end if;
2769
2770 when N_Real_Literal |
2771 N_String_Literal |
2772 N_Character_Literal =>
2773 return;
2774
2775 when N_Range =>
2776 Check_Expr_Constants (Low_Bound (Nod));
2777 Check_Expr_Constants (High_Bound (Nod));
2778
2779 when N_Explicit_Dereference =>
2780 Check_Expr_Constants (Prefix (Nod));
2781
2782 when N_Indexed_Component =>
2783 Check_Expr_Constants (Prefix (Nod));
2784 Check_List_Constants (Expressions (Nod));
2785
2786 when N_Slice =>
2787 Check_Expr_Constants (Prefix (Nod));
2788 Check_Expr_Constants (Discrete_Range (Nod));
2789
2790 when N_Selected_Component =>
2791 Check_Expr_Constants (Prefix (Nod));
2792
2793 when N_Attribute_Reference =>
2794
2795 if Attribute_Name (Nod) = Name_Address
2796 or else
2797 Attribute_Name (Nod) = Name_Access
2798 or else
2799 Attribute_Name (Nod) = Name_Unchecked_Access
2800 or else
2801 Attribute_Name (Nod) = Name_Unrestricted_Access
2802 then
2803 Check_At_Constant_Address (Prefix (Nod));
2804
2805 else
2806 Check_Expr_Constants (Prefix (Nod));
2807 Check_List_Constants (Expressions (Nod));
2808 end if;
2809
2810 when N_Aggregate =>
2811 Check_List_Constants (Component_Associations (Nod));
2812 Check_List_Constants (Expressions (Nod));
2813
2814 when N_Component_Association =>
2815 Check_Expr_Constants (Expression (Nod));
2816
2817 when N_Extension_Aggregate =>
2818 Check_Expr_Constants (Ancestor_Part (Nod));
2819 Check_List_Constants (Component_Associations (Nod));
2820 Check_List_Constants (Expressions (Nod));
2821
2822 when N_Null =>
2823 return;
2824
2825 when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In =>
2826 Check_Expr_Constants (Left_Opnd (Nod));
2827 Check_Expr_Constants (Right_Opnd (Nod));
2828
2829 when N_Unary_Op =>
2830 Check_Expr_Constants (Right_Opnd (Nod));
2831
2832 when N_Type_Conversion |
2833 N_Qualified_Expression |
2834 N_Allocator =>
2835 Check_Expr_Constants (Expression (Nod));
2836
2837 when N_Unchecked_Type_Conversion =>
2838 Check_Expr_Constants (Expression (Nod));
2839
2840 -- If this is a rewritten unchecked conversion, subtypes
2841 -- in this node are those created within the instance.
2842 -- To avoid order of elaboration issues, replace them
2843 -- with their base types. Note that address clauses can
2844 -- cause order of elaboration problems because they are
2845 -- elaborated by the back-end at the point of definition,
2846 -- and may mention entities declared in between (as long
2847 -- as everything is static). It is user-friendly to allow
2848 -- unchecked conversions in this context.
2849
2850 if Nkind (Original_Node (Nod)) = N_Function_Call then
2851 Set_Etype (Expression (Nod),
2852 Base_Type (Etype (Expression (Nod))));
2853 Set_Etype (Nod, Base_Type (Etype (Nod)));
2854 end if;
2855
2856 when N_Function_Call =>
2857 if not Is_Pure (Entity (Name (Nod))) then
2858 Error_Msg_NE
2859 ("invalid address clause for initialized object &!",
2860 Nod, U_Ent);
2861
2862 Error_Msg_NE
2863 ("\function & is not pure ('R'M 13.1(22))!",
2864 Nod, Entity (Name (Nod)));
2865
2866 else
2867 Check_List_Constants (Parameter_Associations (Nod));
2868 end if;
2869
2870 when N_Parameter_Association =>
2871 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
2872
2873 when others =>
2874 Error_Msg_NE
2875 ("invalid address clause for initialized object &!",
2876 Nod, U_Ent);
2877 Error_Msg_NE
2878 ("\must be constant defined before& ('R'M 13.1(22))!",
2879 Nod, U_Ent);
2880 end case;
2881 end Check_Expr_Constants;
2882
2883 --------------------------
2884 -- Check_List_Constants --
2885 --------------------------
2886
2887 procedure Check_List_Constants (Lst : List_Id) is
2888 Nod1 : Node_Id;
2889
2890 begin
2891 if Present (Lst) then
2892 Nod1 := First (Lst);
2893 while Present (Nod1) loop
2894 Check_Expr_Constants (Nod1);
2895 Next (Nod1);
2896 end loop;
2897 end if;
2898 end Check_List_Constants;
2899
2900 -- Start of processing for Check_Constant_Address_Clause
2901
2902 begin
2903 Check_Expr_Constants (Expr);
2904 end Check_Constant_Address_Clause;
2905
2906 ----------------
2907 -- Check_Size --
2908 ----------------
2909
2910 procedure Check_Size
2911 (N : Node_Id;
2912 T : Entity_Id;
2913 Siz : Uint;
2914 Biased : out Boolean)
2915 is
2916 UT : constant Entity_Id := Underlying_Type (T);
2917 M : Uint;
2918
2919 begin
2920 Biased := False;
2921
2922 -- Dismiss cases for generic types or types with previous errors
2923
2924 if No (UT)
2925 or else UT = Any_Type
2926 or else Is_Generic_Type (UT)
2927 or else Is_Generic_Type (Root_Type (UT))
2928 then
2929 return;
2930
2931 -- Check case of bit packed array
2932
2933 elsif Is_Array_Type (UT)
2934 and then Known_Static_Component_Size (UT)
2935 and then Is_Bit_Packed_Array (UT)
2936 then
2937 declare
2938 Asiz : Uint;
2939 Indx : Node_Id;
2940 Ityp : Entity_Id;
2941
2942 begin
2943 Asiz := Component_Size (UT);
2944 Indx := First_Index (UT);
2945 loop
2946 Ityp := Etype (Indx);
2947
2948 -- If non-static bound, then we are not in the business of
2949 -- trying to check the length, and indeed an error will be
2950 -- issued elsewhere, since sizes of non-static array types
2951 -- cannot be set implicitly or explicitly.
2952
2953 if not Is_Static_Subtype (Ityp) then
2954 return;
2955 end if;
2956
2957 -- Otherwise accumulate next dimension
2958
2959 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
2960 Expr_Value (Type_Low_Bound (Ityp)) +
2961 Uint_1);
2962
2963 Next_Index (Indx);
2964 exit when No (Indx);
2965 end loop;
2966
2967 if Asiz <= Siz then
2968 return;
2969 else
2970 Error_Msg_Uint_1 := Asiz;
2971 Error_Msg_NE
2972 ("size for& too small, minimum allowed is ^", N, T);
2973 Set_Esize (T, Asiz);
2974 Set_RM_Size (T, Asiz);
2975 end if;
2976 end;
2977
2978 -- All other composite types are ignored
2979
2980 elsif Is_Composite_Type (UT) then
2981 return;
2982
2983 -- For fixed-point types, don't check minimum if type is not frozen,
2984 -- since we don't know all the characteristics of the type that can
2985 -- affect the size (e.g. a specified small) till freeze time.
2986
2987 elsif Is_Fixed_Point_Type (UT)
2988 and then not Is_Frozen (UT)
2989 then
2990 null;
2991
2992 -- Cases for which a minimum check is required
2993
2994 else
2995 -- Ignore if specified size is correct for the type
2996
2997 if Known_Esize (UT) and then Siz = Esize (UT) then
2998 return;
2999 end if;
3000
3001 -- Otherwise get minimum size
3002
3003 M := UI_From_Int (Minimum_Size (UT));
3004
3005 if Siz < M then
3006
3007 -- Size is less than minimum size, but one possibility remains
3008 -- that we can manage with the new size if we bias the type
3009
3010 M := UI_From_Int (Minimum_Size (UT, Biased => True));
3011
3012 if Siz < M then
3013 Error_Msg_Uint_1 := M;
3014 Error_Msg_NE
3015 ("size for& too small, minimum allowed is ^", N, T);
3016 Set_Esize (T, M);
3017 Set_RM_Size (T, M);
3018 else
3019 Biased := True;
3020 end if;
3021 end if;
3022 end if;
3023 end Check_Size;
3024
3025 -------------------------
3026 -- Get_Alignment_Value --
3027 -------------------------
3028
3029 function Get_Alignment_Value (Expr : Node_Id) return Uint is
3030 Align : constant Uint := Static_Integer (Expr);
3031
3032 begin
3033 if Align = No_Uint then
3034 return No_Uint;
3035
3036 elsif Align <= 0 then
3037 Error_Msg_N ("alignment value must be positive", Expr);
3038 return No_Uint;
3039
3040 else
3041 for J in Int range 0 .. 64 loop
3042 declare
3043 M : constant Uint := Uint_2 ** J;
3044
3045 begin
3046 exit when M = Align;
3047
3048 if M > Align then
3049 Error_Msg_N
3050 ("alignment value must be power of 2", Expr);
3051 return No_Uint;
3052 end if;
3053 end;
3054 end loop;
3055
3056 return Align;
3057 end if;
3058 end Get_Alignment_Value;
3059
3060 ----------------
3061 -- Initialize --
3062 ----------------
3063
3064 procedure Initialize is
3065 begin
3066 Unchecked_Conversions.Init;
3067 end Initialize;
3068
3069 -------------------------
3070 -- Is_Operational_Item --
3071 -------------------------
3072
3073 function Is_Operational_Item (N : Node_Id) return Boolean is
3074 begin
3075 if Nkind (N) /= N_Attribute_Definition_Clause then
3076 return False;
3077 else
3078 declare
3079 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3080
3081 begin
3082 return Id = Attribute_Input
3083 or else Id = Attribute_Output
3084 or else Id = Attribute_Read
3085 or else Id = Attribute_Write
3086 or else Id = Attribute_External_Tag;
3087 end;
3088 end if;
3089 end Is_Operational_Item;
3090
3091 --------------------------------------
3092 -- Mark_Aliased_Address_As_Volatile --
3093 --------------------------------------
3094
3095 procedure Mark_Aliased_Address_As_Volatile (N : Node_Id) is
3096 Ent : constant Entity_Id := Address_Aliased_Entity (N);
3097
3098 begin
3099 if Present (Ent) then
3100 Set_Treat_As_Volatile (Ent);
3101 end if;
3102 end Mark_Aliased_Address_As_Volatile;
3103
3104 ------------------
3105 -- Minimum_Size --
3106 ------------------
3107
3108 function Minimum_Size
3109 (T : Entity_Id;
3110 Biased : Boolean := False) return Nat
3111 is
3112 Lo : Uint := No_Uint;
3113 Hi : Uint := No_Uint;
3114 LoR : Ureal := No_Ureal;
3115 HiR : Ureal := No_Ureal;
3116 LoSet : Boolean := False;
3117 HiSet : Boolean := False;
3118 B : Uint;
3119 S : Nat;
3120 Ancest : Entity_Id;
3121 R_Typ : constant Entity_Id := Root_Type (T);
3122
3123 begin
3124 -- If bad type, return 0
3125
3126 if T = Any_Type then
3127 return 0;
3128
3129 -- For generic types, just return zero. There cannot be any legitimate
3130 -- need to know such a size, but this routine may be called with a
3131 -- generic type as part of normal processing.
3132
3133 elsif Is_Generic_Type (R_Typ)
3134 or else R_Typ = Any_Type
3135 then
3136 return 0;
3137
3138 -- Access types. Normally an access type cannot have a size smaller
3139 -- than the size of System.Address. The exception is on VMS, where
3140 -- we have short and long addresses, and it is possible for an access
3141 -- type to have a short address size (and thus be less than the size
3142 -- of System.Address itself). We simply skip the check for VMS, and
3143 -- leave the back end to do the check.
3144
3145 elsif Is_Access_Type (T) then
3146 if OpenVMS_On_Target then
3147 return 0;
3148 else
3149 return System_Address_Size;
3150 end if;
3151
3152 -- Floating-point types
3153
3154 elsif Is_Floating_Point_Type (T) then
3155 return UI_To_Int (Esize (R_Typ));
3156
3157 -- Discrete types
3158
3159 elsif Is_Discrete_Type (T) then
3160
3161 -- The following loop is looking for the nearest compile time
3162 -- known bounds following the ancestor subtype chain. The idea
3163 -- is to find the most restrictive known bounds information.
3164
3165 Ancest := T;
3166 loop
3167 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3168 return 0;
3169 end if;
3170
3171 if not LoSet then
3172 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3173 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3174 LoSet := True;
3175 exit when HiSet;
3176 end if;
3177 end if;
3178
3179 if not HiSet then
3180 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3181 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3182 HiSet := True;
3183 exit when LoSet;
3184 end if;
3185 end if;
3186
3187 Ancest := Ancestor_Subtype (Ancest);
3188
3189 if No (Ancest) then
3190 Ancest := Base_Type (T);
3191
3192 if Is_Generic_Type (Ancest) then
3193 return 0;
3194 end if;
3195 end if;
3196 end loop;
3197
3198 -- Fixed-point types. We can't simply use Expr_Value to get the
3199 -- Corresponding_Integer_Value values of the bounds, since these
3200 -- do not get set till the type is frozen, and this routine can
3201 -- be called before the type is frozen. Similarly the test for
3202 -- bounds being static needs to include the case where we have
3203 -- unanalyzed real literals for the same reason.
3204
3205 elsif Is_Fixed_Point_Type (T) then
3206
3207 -- The following loop is looking for the nearest compile time
3208 -- known bounds following the ancestor subtype chain. The idea
3209 -- is to find the most restrictive known bounds information.
3210
3211 Ancest := T;
3212 loop
3213 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3214 return 0;
3215 end if;
3216
3217 if not LoSet then
3218 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3219 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3220 then
3221 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3222 LoSet := True;
3223 exit when HiSet;
3224 end if;
3225 end if;
3226
3227 if not HiSet then
3228 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3229 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3230 then
3231 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3232 HiSet := True;
3233 exit when LoSet;
3234 end if;
3235 end if;
3236
3237 Ancest := Ancestor_Subtype (Ancest);
3238
3239 if No (Ancest) then
3240 Ancest := Base_Type (T);
3241
3242 if Is_Generic_Type (Ancest) then
3243 return 0;
3244 end if;
3245 end if;
3246 end loop;
3247
3248 Lo := UR_To_Uint (LoR / Small_Value (T));
3249 Hi := UR_To_Uint (HiR / Small_Value (T));
3250
3251 -- No other types allowed
3252
3253 else
3254 raise Program_Error;
3255 end if;
3256
3257 -- Fall through with Hi and Lo set. Deal with biased case
3258
3259 if (Biased and then not Is_Fixed_Point_Type (T))
3260 or else Has_Biased_Representation (T)
3261 then
3262 Hi := Hi - Lo;
3263 Lo := Uint_0;
3264 end if;
3265
3266 -- Signed case. Note that we consider types like range 1 .. -1 to be
3267 -- signed for the purpose of computing the size, since the bounds
3268 -- have to be accomodated in the base type.
3269
3270 if Lo < 0 or else Hi < 0 then
3271 S := 1;
3272 B := Uint_1;
3273
3274 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3275 -- Note that we accommodate the case where the bounds cross. This
3276 -- can happen either because of the way the bounds are declared
3277 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3278
3279 while Lo < -B
3280 or else Hi < -B
3281 or else Lo >= B
3282 or else Hi >= B
3283 loop
3284 B := Uint_2 ** S;
3285 S := S + 1;
3286 end loop;
3287
3288 -- Unsigned case
3289
3290 else
3291 -- If both bounds are positive, make sure that both are represen-
3292 -- table in the case where the bounds are crossed. This can happen
3293 -- either because of the way the bounds are declared, or because of
3294 -- the algorithm in Freeze_Fixed_Point_Type.
3295
3296 if Lo > Hi then
3297 Hi := Lo;
3298 end if;
3299
3300 -- S = size, (can accommodate 0 .. (2**size - 1))
3301
3302 S := 0;
3303 while Hi >= Uint_2 ** S loop
3304 S := S + 1;
3305 end loop;
3306 end if;
3307
3308 return S;
3309 end Minimum_Size;
3310
3311 -------------------------
3312 -- New_Stream_Function --
3313 -------------------------
3314
3315 procedure New_Stream_Function
3316 (N : Node_Id;
3317 Ent : Entity_Id;
3318 Subp : Entity_Id;
3319 Nam : TSS_Name_Type)
3320 is
3321 Loc : constant Source_Ptr := Sloc (N);
3322 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3323 Subp_Id : Entity_Id;
3324 Subp_Decl : Node_Id;
3325 F : Entity_Id;
3326 Etyp : Entity_Id;
3327
3328 function Build_Spec return Node_Id;
3329 -- Used for declaration and renaming declaration, so that this is
3330 -- treated as a renaming_as_body.
3331
3332 ----------------
3333 -- Build_Spec --
3334 ----------------
3335
3336 function Build_Spec return Node_Id is
3337 begin
3338 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3339
3340 return
3341 Make_Function_Specification (Loc,
3342 Defining_Unit_Name => Subp_Id,
3343 Parameter_Specifications =>
3344 New_List (
3345 Make_Parameter_Specification (Loc,
3346 Defining_Identifier =>
3347 Make_Defining_Identifier (Loc, Name_S),
3348 Parameter_Type =>
3349 Make_Access_Definition (Loc,
3350 Subtype_Mark =>
3351 New_Reference_To (
3352 Designated_Type (Etype (F)), Loc)))),
3353
3354 Subtype_Mark =>
3355 New_Reference_To (Etyp, Loc));
3356 end Build_Spec;
3357
3358 -- Start of processing for New_Stream_Function
3359
3360 begin
3361 F := First_Formal (Subp);
3362 Etyp := Etype (Subp);
3363
3364 if not Is_Tagged_Type (Ent) then
3365 Subp_Decl :=
3366 Make_Subprogram_Declaration (Loc,
3367 Specification => Build_Spec);
3368 Insert_Action (N, Subp_Decl);
3369 end if;
3370
3371 Subp_Decl :=
3372 Make_Subprogram_Renaming_Declaration (Loc,
3373 Specification => Build_Spec,
3374 Name => New_Reference_To (Subp, Loc));
3375
3376 if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then
3377 Set_TSS (Base_Type (Ent), Subp_Id);
3378 else
3379 Insert_Action (N, Subp_Decl);
3380 Copy_TSS (Subp_Id, Base_Type (Ent));
3381 end if;
3382 end New_Stream_Function;
3383
3384 --------------------------
3385 -- New_Stream_Procedure --
3386 --------------------------
3387
3388 procedure New_Stream_Procedure
3389 (N : Node_Id;
3390 Ent : Entity_Id;
3391 Subp : Entity_Id;
3392 Nam : TSS_Name_Type;
3393 Out_P : Boolean := False)
3394 is
3395 Loc : constant Source_Ptr := Sloc (N);
3396 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3397 Subp_Id : Entity_Id;
3398 Subp_Decl : Node_Id;
3399 F : Entity_Id;
3400 Etyp : Entity_Id;
3401
3402 function Build_Spec return Node_Id;
3403 -- Used for declaration and renaming declaration, so that this is
3404 -- treated as a renaming_as_body.
3405
3406 ----------------
3407 -- Build_Spec --
3408 ----------------
3409
3410 function Build_Spec return Node_Id is
3411 begin
3412 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3413
3414 return
3415 Make_Procedure_Specification (Loc,
3416 Defining_Unit_Name => Subp_Id,
3417 Parameter_Specifications =>
3418 New_List (
3419 Make_Parameter_Specification (Loc,
3420 Defining_Identifier =>
3421 Make_Defining_Identifier (Loc, Name_S),
3422 Parameter_Type =>
3423 Make_Access_Definition (Loc,
3424 Subtype_Mark =>
3425 New_Reference_To (
3426 Designated_Type (Etype (F)), Loc))),
3427
3428 Make_Parameter_Specification (Loc,
3429 Defining_Identifier =>
3430 Make_Defining_Identifier (Loc, Name_V),
3431 Out_Present => Out_P,
3432 Parameter_Type =>
3433 New_Reference_To (Etyp, Loc))));
3434 end Build_Spec;
3435
3436 -- Start of processing for New_Stream_Procedure
3437
3438 begin
3439 F := First_Formal (Subp);
3440 Etyp := Etype (Next_Formal (F));
3441
3442 if not Is_Tagged_Type (Ent) then
3443 Subp_Decl :=
3444 Make_Subprogram_Declaration (Loc,
3445 Specification => Build_Spec);
3446 Insert_Action (N, Subp_Decl);
3447 end if;
3448
3449 Subp_Decl :=
3450 Make_Subprogram_Renaming_Declaration (Loc,
3451 Specification => Build_Spec,
3452 Name => New_Reference_To (Subp, Loc));
3453
3454 if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then
3455 Set_TSS (Base_Type (Ent), Subp_Id);
3456 else
3457 Insert_Action (N, Subp_Decl);
3458 Copy_TSS (Subp_Id, Base_Type (Ent));
3459 end if;
3460 end New_Stream_Procedure;
3461
3462 ------------------------
3463 -- Rep_Item_Too_Early --
3464 ------------------------
3465
3466 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3467 begin
3468 -- Cannot apply rep items that are not operational items
3469 -- to generic types
3470
3471 if Is_Operational_Item (N) then
3472 return False;
3473
3474 elsif Is_Type (T)
3475 and then Is_Generic_Type (Root_Type (T))
3476 then
3477 Error_Msg_N
3478 ("representation item not allowed for generic type", N);
3479 return True;
3480 end if;
3481
3482 -- Otherwise check for incompleted type
3483
3484 if Is_Incomplete_Or_Private_Type (T)
3485 and then No (Underlying_Type (T))
3486 then
3487 Error_Msg_N
3488 ("representation item must be after full type declaration", N);
3489 return True;
3490
3491 -- If the type has incompleted components, a representation clause is
3492 -- illegal but stream attributes and Convention pragmas are correct.
3493
3494 elsif Has_Private_Component (T) then
3495 if Nkind (N) = N_Pragma then
3496 return False;
3497 else
3498 Error_Msg_N
3499 ("representation item must appear after type is fully defined",
3500 N);
3501 return True;
3502 end if;
3503 else
3504 return False;
3505 end if;
3506 end Rep_Item_Too_Early;
3507
3508 -----------------------
3509 -- Rep_Item_Too_Late --
3510 -----------------------
3511
3512 function Rep_Item_Too_Late
3513 (T : Entity_Id;
3514 N : Node_Id;
3515 FOnly : Boolean := False) return Boolean
3516 is
3517 S : Entity_Id;
3518 Parent_Type : Entity_Id;
3519
3520 procedure Too_Late;
3521 -- Output the too late message. Note that this is not considered a
3522 -- serious error, since the effect is simply that we ignore the
3523 -- representation clause in this case.
3524
3525 --------------
3526 -- Too_Late --
3527 --------------
3528
3529 procedure Too_Late is
3530 begin
3531 Error_Msg_N ("|representation item appears too late!", N);
3532 end Too_Late;
3533
3534 -- Start of processing for Rep_Item_Too_Late
3535
3536 begin
3537 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
3538 -- types, which may be frozen if they appear in a representation clause
3539 -- for a local type.
3540
3541 if Is_Frozen (T)
3542 and then not From_With_Type (T)
3543 then
3544 Too_Late;
3545 S := First_Subtype (T);
3546
3547 if Present (Freeze_Node (S)) then
3548 Error_Msg_NE
3549 ("?no more representation items for }!", Freeze_Node (S), S);
3550 end if;
3551
3552 return True;
3553
3554 -- Check for case of non-tagged derived type whose parent either has
3555 -- primitive operations, or is a by reference type (RM 13.1(10)).
3556
3557 elsif Is_Type (T)
3558 and then not FOnly
3559 and then Is_Derived_Type (T)
3560 and then not Is_Tagged_Type (T)
3561 then
3562 Parent_Type := Etype (Base_Type (T));
3563
3564 if Has_Primitive_Operations (Parent_Type) then
3565 Too_Late;
3566 Error_Msg_NE
3567 ("primitive operations already defined for&!", N, Parent_Type);
3568 return True;
3569
3570 elsif Is_By_Reference_Type (Parent_Type) then
3571 Too_Late;
3572 Error_Msg_NE
3573 ("parent type & is a by reference type!", N, Parent_Type);
3574 return True;
3575 end if;
3576 end if;
3577
3578 -- No error, link item into head of chain of rep items for the entity
3579
3580 Record_Rep_Item (T, N);
3581 return False;
3582 end Rep_Item_Too_Late;
3583
3584 -------------------------
3585 -- Same_Representation --
3586 -------------------------
3587
3588 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
3589 T1 : constant Entity_Id := Underlying_Type (Typ1);
3590 T2 : constant Entity_Id := Underlying_Type (Typ2);
3591
3592 begin
3593 -- A quick check, if base types are the same, then we definitely have
3594 -- the same representation, because the subtype specific representation
3595 -- attributes (Size and Alignment) do not affect representation from
3596 -- the point of view of this test.
3597
3598 if Base_Type (T1) = Base_Type (T2) then
3599 return True;
3600
3601 elsif Is_Private_Type (Base_Type (T2))
3602 and then Base_Type (T1) = Full_View (Base_Type (T2))
3603 then
3604 return True;
3605 end if;
3606
3607 -- Tagged types never have differing representations
3608
3609 if Is_Tagged_Type (T1) then
3610 return True;
3611 end if;
3612
3613 -- Representations are definitely different if conventions differ
3614
3615 if Convention (T1) /= Convention (T2) then
3616 return False;
3617 end if;
3618
3619 -- Representations are different if component alignments differ
3620
3621 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
3622 and then
3623 (Is_Record_Type (T2) or else Is_Array_Type (T2))
3624 and then Component_Alignment (T1) /= Component_Alignment (T2)
3625 then
3626 return False;
3627 end if;
3628
3629 -- For arrays, the only real issue is component size. If we know the
3630 -- component size for both arrays, and it is the same, then that's
3631 -- good enough to know we don't have a change of representation.
3632
3633 if Is_Array_Type (T1) then
3634 if Known_Component_Size (T1)
3635 and then Known_Component_Size (T2)
3636 and then Component_Size (T1) = Component_Size (T2)
3637 then
3638 return True;
3639 end if;
3640 end if;
3641
3642 -- Types definitely have same representation if neither has non-standard
3643 -- representation since default representations are always consistent.
3644 -- If only one has non-standard representation, and the other does not,
3645 -- then we consider that they do not have the same representation. They
3646 -- might, but there is no way of telling early enough.
3647
3648 if Has_Non_Standard_Rep (T1) then
3649 if not Has_Non_Standard_Rep (T2) then
3650 return False;
3651 end if;
3652 else
3653 return not Has_Non_Standard_Rep (T2);
3654 end if;
3655
3656 -- Here the two types both have non-standard representation, and we
3657 -- need to determine if they have the same non-standard representation
3658
3659 -- For arrays, we simply need to test if the component sizes are the
3660 -- same. Pragma Pack is reflected in modified component sizes, so this
3661 -- check also deals with pragma Pack.
3662
3663 if Is_Array_Type (T1) then
3664 return Component_Size (T1) = Component_Size (T2);
3665
3666 -- Tagged types always have the same representation, because it is not
3667 -- possible to specify different representations for common fields.
3668
3669 elsif Is_Tagged_Type (T1) then
3670 return True;
3671
3672 -- Case of record types
3673
3674 elsif Is_Record_Type (T1) then
3675
3676 -- Packed status must conform
3677
3678 if Is_Packed (T1) /= Is_Packed (T2) then
3679 return False;
3680
3681 -- Otherwise we must check components. Typ2 maybe a constrained
3682 -- subtype with fewer components, so we compare the components
3683 -- of the base types.
3684
3685 else
3686 Record_Case : declare
3687 CD1, CD2 : Entity_Id;
3688
3689 function Same_Rep return Boolean;
3690 -- CD1 and CD2 are either components or discriminants. This
3691 -- function tests whether the two have the same representation
3692
3693 --------------
3694 -- Same_Rep --
3695 --------------
3696
3697 function Same_Rep return Boolean is
3698 begin
3699 if No (Component_Clause (CD1)) then
3700 return No (Component_Clause (CD2));
3701
3702 else
3703 return
3704 Present (Component_Clause (CD2))
3705 and then
3706 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
3707 and then
3708 Esize (CD1) = Esize (CD2);
3709 end if;
3710 end Same_Rep;
3711
3712 -- Start processing for Record_Case
3713
3714 begin
3715 if Has_Discriminants (T1) then
3716 CD1 := First_Discriminant (T1);
3717 CD2 := First_Discriminant (T2);
3718
3719 -- The number of discriminants may be different if the
3720 -- derived type has fewer (constrained by values). The
3721 -- invisible discriminants retain the representation of
3722 -- the original, so the discrepancy does not per se
3723 -- indicate a different representation.
3724
3725 while Present (CD1)
3726 and then Present (CD2)
3727 loop
3728 if not Same_Rep then
3729 return False;
3730 else
3731 Next_Discriminant (CD1);
3732 Next_Discriminant (CD2);
3733 end if;
3734 end loop;
3735 end if;
3736
3737 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
3738 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
3739
3740 while Present (CD1) loop
3741 if not Same_Rep then
3742 return False;
3743 else
3744 Next_Component (CD1);
3745 Next_Component (CD2);
3746 end if;
3747 end loop;
3748
3749 return True;
3750 end Record_Case;
3751 end if;
3752
3753 -- For enumeration types, we must check each literal to see if the
3754 -- representation is the same. Note that we do not permit enumeration
3755 -- reprsentation clauses for Character and Wide_Character, so these
3756 -- cases were already dealt with.
3757
3758 elsif Is_Enumeration_Type (T1) then
3759
3760 Enumeration_Case : declare
3761 L1, L2 : Entity_Id;
3762
3763 begin
3764 L1 := First_Literal (T1);
3765 L2 := First_Literal (T2);
3766
3767 while Present (L1) loop
3768 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
3769 return False;
3770 else
3771 Next_Literal (L1);
3772 Next_Literal (L2);
3773 end if;
3774 end loop;
3775
3776 return True;
3777
3778 end Enumeration_Case;
3779
3780 -- Any other types have the same representation for these purposes
3781
3782 else
3783 return True;
3784 end if;
3785 end Same_Representation;
3786
3787 --------------------
3788 -- Set_Enum_Esize --
3789 --------------------
3790
3791 procedure Set_Enum_Esize (T : Entity_Id) is
3792 Lo : Uint;
3793 Hi : Uint;
3794 Sz : Nat;
3795
3796 begin
3797 Init_Alignment (T);
3798
3799 -- Find the minimum standard size (8,16,32,64) that fits
3800
3801 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
3802 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
3803
3804 if Lo < 0 then
3805 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
3806 Sz := Standard_Character_Size; -- May be > 8 on some targets
3807
3808 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
3809 Sz := 16;
3810
3811 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
3812 Sz := 32;
3813
3814 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
3815 Sz := 64;
3816 end if;
3817
3818 else
3819 if Hi < Uint_2**08 then
3820 Sz := Standard_Character_Size; -- May be > 8 on some targets
3821
3822 elsif Hi < Uint_2**16 then
3823 Sz := 16;
3824
3825 elsif Hi < Uint_2**32 then
3826 Sz := 32;
3827
3828 else pragma Assert (Hi < Uint_2**63);
3829 Sz := 64;
3830 end if;
3831 end if;
3832
3833 -- That minimum is the proper size unless we have a foreign convention
3834 -- and the size required is 32 or less, in which case we bump the size
3835 -- up to 32. This is required for C and C++ and seems reasonable for
3836 -- all other foreign conventions.
3837
3838 if Has_Foreign_Convention (T)
3839 and then Esize (T) < Standard_Integer_Size
3840 then
3841 Init_Esize (T, Standard_Integer_Size);
3842
3843 else
3844 Init_Esize (T, Sz);
3845 end if;
3846 end Set_Enum_Esize;
3847
3848 -----------------------------------
3849 -- Validate_Unchecked_Conversion --
3850 -----------------------------------
3851
3852 procedure Validate_Unchecked_Conversion
3853 (N : Node_Id;
3854 Act_Unit : Entity_Id)
3855 is
3856 Source : Entity_Id;
3857 Target : Entity_Id;
3858 Vnode : Node_Id;
3859
3860 begin
3861 -- Obtain source and target types. Note that we call Ancestor_Subtype
3862 -- here because the processing for generic instantiation always makes
3863 -- subtypes, and we want the original frozen actual types.
3864
3865 -- If we are dealing with private types, then do the check on their
3866 -- fully declared counterparts if the full declarations have been
3867 -- encountered (they don't have to be visible, but they must exist!)
3868
3869 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
3870
3871 if Is_Private_Type (Source)
3872 and then Present (Underlying_Type (Source))
3873 then
3874 Source := Underlying_Type (Source);
3875 end if;
3876
3877 Target := Ancestor_Subtype (Etype (Act_Unit));
3878
3879 -- If either type is generic, the instantiation happens within a
3880 -- generic unit, and there is nothing to check. The proper check
3881 -- will happen when the enclosing generic is instantiated.
3882
3883 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
3884 return;
3885 end if;
3886
3887 if Is_Private_Type (Target)
3888 and then Present (Underlying_Type (Target))
3889 then
3890 Target := Underlying_Type (Target);
3891 end if;
3892
3893 -- Source may be unconstrained array, but not target
3894
3895 if Is_Array_Type (Target)
3896 and then not Is_Constrained (Target)
3897 then
3898 Error_Msg_N
3899 ("unchecked conversion to unconstrained array not allowed", N);
3900 return;
3901 end if;
3902
3903 -- Make entry in unchecked conversion table for later processing
3904 -- by Validate_Unchecked_Conversions, which will check sizes and
3905 -- alignments (using values set by the back-end where possible).
3906 -- This is only done if the appropriate warning is active
3907
3908 if Warn_On_Unchecked_Conversion then
3909 Unchecked_Conversions.Append
3910 (New_Val => UC_Entry'
3911 (Enode => N,
3912 Source => Source,
3913 Target => Target));
3914
3915 -- If both sizes are known statically now, then back end annotation
3916 -- is not required to do a proper check but if either size is not
3917 -- known statically, then we need the annotation.
3918
3919 if Known_Static_RM_Size (Source)
3920 and then Known_Static_RM_Size (Target)
3921 then
3922 null;
3923 else
3924 Back_Annotate_Rep_Info := True;
3925 end if;
3926 end if;
3927
3928 -- If unchecked conversion to access type, and access type is
3929 -- declared in the same unit as the unchecked conversion, then
3930 -- set the No_Strict_Aliasing flag (no strict aliasing is
3931 -- implicit in this situation).
3932
3933 if Is_Access_Type (Target) and then
3934 In_Same_Source_Unit (Target, N)
3935 then
3936 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
3937 end if;
3938
3939 -- Generate N_Validate_Unchecked_Conversion node for back end in
3940 -- case the back end needs to perform special validation checks.
3941
3942 -- Shouldn't this be in exp_ch13, since the check only gets done
3943 -- if we have full expansion and the back end is called ???
3944
3945 Vnode :=
3946 Make_Validate_Unchecked_Conversion (Sloc (N));
3947 Set_Source_Type (Vnode, Source);
3948 Set_Target_Type (Vnode, Target);
3949
3950 -- If the unchecked conversion node is in a list, just insert before
3951 -- it. If not we have some strange case, not worth bothering about.
3952
3953 if Is_List_Member (N) then
3954 Insert_After (N, Vnode);
3955 end if;
3956 end Validate_Unchecked_Conversion;
3957
3958 ------------------------------------
3959 -- Validate_Unchecked_Conversions --
3960 ------------------------------------
3961
3962 procedure Validate_Unchecked_Conversions is
3963 begin
3964 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
3965 declare
3966 T : UC_Entry renames Unchecked_Conversions.Table (N);
3967
3968 Enode : constant Node_Id := T.Enode;
3969 Source : constant Entity_Id := T.Source;
3970 Target : constant Entity_Id := T.Target;
3971
3972 Source_Siz : Uint;
3973 Target_Siz : Uint;
3974
3975 begin
3976 -- This validation check, which warns if we have unequal sizes
3977 -- for unchecked conversion, and thus potentially implementation
3978 -- dependent semantics, is one of the few occasions on which we
3979 -- use the official RM size instead of Esize. See description
3980 -- in Einfo "Handling of Type'Size Values" for details.
3981
3982 if Serious_Errors_Detected = 0
3983 and then Known_Static_RM_Size (Source)
3984 and then Known_Static_RM_Size (Target)
3985 then
3986 Source_Siz := RM_Size (Source);
3987 Target_Siz := RM_Size (Target);
3988
3989 if Source_Siz /= Target_Siz then
3990 Error_Msg_N
3991 ("types for unchecked conversion have different sizes?",
3992 Enode);
3993
3994 if All_Errors_Mode then
3995 Error_Msg_Name_1 := Chars (Source);
3996 Error_Msg_Uint_1 := Source_Siz;
3997 Error_Msg_Name_2 := Chars (Target);
3998 Error_Msg_Uint_2 := Target_Siz;
3999 Error_Msg_N
4000 ("\size of % is ^, size of % is ^?", Enode);
4001
4002 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
4003
4004 if Is_Discrete_Type (Source)
4005 and then Is_Discrete_Type (Target)
4006 then
4007 if Source_Siz > Target_Siz then
4008 Error_Msg_N
4009 ("\^ high order bits of source will be ignored?",
4010 Enode);
4011
4012 elsif Is_Unsigned_Type (Source) then
4013 Error_Msg_N
4014 ("\source will be extended with ^ high order " &
4015 "zero bits?", Enode);
4016
4017 else
4018 Error_Msg_N
4019 ("\source will be extended with ^ high order " &
4020 "sign bits?",
4021 Enode);
4022 end if;
4023
4024 elsif Source_Siz < Target_Siz then
4025 if Is_Discrete_Type (Target) then
4026 if Bytes_Big_Endian then
4027 Error_Msg_N
4028 ("\target value will include ^ undefined " &
4029 "low order bits?",
4030 Enode);
4031 else
4032 Error_Msg_N
4033 ("\target value will include ^ undefined " &
4034 "high order bits?",
4035 Enode);
4036 end if;
4037
4038 else
4039 Error_Msg_N
4040 ("\^ trailing bits of target value will be " &
4041 "undefined?", Enode);
4042 end if;
4043
4044 else pragma Assert (Source_Siz > Target_Siz);
4045 Error_Msg_N
4046 ("\^ trailing bits of source will be ignored?",
4047 Enode);
4048 end if;
4049 end if;
4050 end if;
4051 end if;
4052
4053 -- If both types are access types, we need to check the alignment.
4054 -- If the alignment of both is specified, we can do it here.
4055
4056 if Serious_Errors_Detected = 0
4057 and then Ekind (Source) in Access_Kind
4058 and then Ekind (Target) in Access_Kind
4059 and then Target_Strict_Alignment
4060 and then Present (Designated_Type (Source))
4061 and then Present (Designated_Type (Target))
4062 then
4063 declare
4064 D_Source : constant Entity_Id := Designated_Type (Source);
4065 D_Target : constant Entity_Id := Designated_Type (Target);
4066
4067 begin
4068 if Known_Alignment (D_Source)
4069 and then Known_Alignment (D_Target)
4070 then
4071 declare
4072 Source_Align : constant Uint := Alignment (D_Source);
4073 Target_Align : constant Uint := Alignment (D_Target);
4074
4075 begin
4076 if Source_Align < Target_Align
4077 and then not Is_Tagged_Type (D_Source)
4078 then
4079 Error_Msg_Uint_1 := Target_Align;
4080 Error_Msg_Uint_2 := Source_Align;
4081 Error_Msg_Node_2 := D_Source;
4082 Error_Msg_NE
4083 ("alignment of & (^) is stricter than " &
4084 "alignment of & (^)?", Enode, D_Target);
4085
4086 if All_Errors_Mode then
4087 Error_Msg_N
4088 ("\resulting access value may have invalid " &
4089 "alignment?", Enode);
4090 end if;
4091 end if;
4092 end;
4093 end if;
4094 end;
4095 end if;
4096 end;
4097 end loop;
4098 end Validate_Unchecked_Conversions;
4099
4100 end Sem_Ch13;
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