?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
fixing pr42337
[official-gcc.git] / gcc / ada / sem_ch13.adb
blob6542dd28174d52cc520fd3435095a6a9d0571b56
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) 1992-2009, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
26 with Atree; use Atree;
27 with Checks; use Checks;
28 with Einfo; use Einfo;
29 with Errout; use Errout;
30 with Exp_Tss; use Exp_Tss;
31 with Exp_Util; use Exp_Util;
32 with Lib; use Lib;
33 with Lib.Xref; use Lib.Xref;
34 with Namet; use Namet;
35 with Nlists; use Nlists;
36 with Nmake; use Nmake;
37 with Opt; use Opt;
38 with Restrict; use Restrict;
39 with Rident; use Rident;
40 with Rtsfind; use Rtsfind;
41 with Sem; use Sem;
42 with Sem_Aux; use Sem_Aux;
43 with Sem_Ch3; use Sem_Ch3;
44 with Sem_Ch8; use Sem_Ch8;
45 with Sem_Eval; use Sem_Eval;
46 with Sem_Res; use Sem_Res;
47 with Sem_Type; use Sem_Type;
48 with Sem_Util; use Sem_Util;
49 with Sem_Warn; use Sem_Warn;
50 with Snames; use Snames;
51 with Stand; use Stand;
52 with Sinfo; use Sinfo;
53 with Table;
54 with Targparm; use Targparm;
55 with Ttypes; use Ttypes;
56 with Tbuild; use Tbuild;
57 with Urealp; use Urealp;
58
59 with GNAT.Heap_Sort_G;
60
61 package body Sem_Ch13 is
62
63 SSU : constant Pos := System_Storage_Unit;
64 -- Convenient short hand for commonly used constant
65
66 -----------------------
67 -- Local Subprograms --
68 -----------------------
69
70 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id);
71 -- This routine is called after setting the Esize of type entity Typ.
72 -- The purpose is to deal with the situation where an alignment has been
73 -- inherited from a derived type that is no longer appropriate for the
74 -- new Esize value. In this case, we reset the Alignment to unknown.
75
76 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id);
77 -- Given two entities for record components or discriminants, checks
78 -- if they have overlapping component clauses and issues errors if so.
79
80 function Get_Alignment_Value (Expr : Node_Id) return Uint;
81 -- Given the expression for an alignment value, returns the corresponding
82 -- Uint value. If the value is inappropriate, then error messages are
83 -- posted as required, and a value of No_Uint is returned.
84
85 function Is_Operational_Item (N : Node_Id) return Boolean;
86 -- A specification for a stream attribute is allowed before the full
87 -- type is declared, as explained in AI-00137 and the corrigendum.
88 -- Attributes that do not specify a representation characteristic are
89 -- operational attributes.
90
91 procedure New_Stream_Subprogram
92 (N : Node_Id;
93 Ent : Entity_Id;
94 Subp : Entity_Id;
95 Nam : TSS_Name_Type);
96 -- Create a subprogram renaming of a given stream attribute to the
97 -- designated subprogram and then in the tagged case, provide this as a
98 -- primitive operation, or in the non-tagged case make an appropriate TSS
99 -- entry. This is more properly an expansion activity than just semantics,
100 -- but the presence of user-defined stream functions for limited types is a
101 -- legality check, which is why this takes place here rather than in
102 -- exp_ch13, where it was previously. Nam indicates the name of the TSS
103 -- function to be generated.
104 --
105 -- To avoid elaboration anomalies with freeze nodes, for untagged types
106 -- we generate both a subprogram declaration and a subprogram renaming
107 -- declaration, so that the attribute specification is handled as a
108 -- renaming_as_body. For tagged types, the specification is one of the
109 -- primitive specs.
110
111 ----------------------------------------------
112 -- Table for Validate_Unchecked_Conversions --
113 ----------------------------------------------
114
115 -- The following table collects unchecked conversions for validation.
116 -- Entries are made by Validate_Unchecked_Conversion and then the
117 -- call to Validate_Unchecked_Conversions does the actual error
118 -- checking and posting of warnings. The reason for this delayed
119 -- processing is to take advantage of back-annotations of size and
120 -- alignment values performed by the back end.
121
122 -- Note: the reason we store a Source_Ptr value instead of a Node_Id
123 -- is that by the time Validate_Unchecked_Conversions is called, Sprint
124 -- will already have modified all Sloc values if the -gnatD option is set.
125
126 type UC_Entry is record
127 Eloc : Source_Ptr; -- node used for posting warnings
128 Source : Entity_Id; -- source type for unchecked conversion
129 Target : Entity_Id; -- target type for unchecked conversion
130 end record;
131
132 package Unchecked_Conversions is new Table.Table (
133 Table_Component_Type => UC_Entry,
134 Table_Index_Type => Int,
135 Table_Low_Bound => 1,
136 Table_Initial => 50,
137 Table_Increment => 200,
138 Table_Name => "Unchecked_Conversions");
139
140 ----------------------------------------
141 -- Table for Validate_Address_Clauses --
142 ----------------------------------------
143
144 -- If an address clause has the form
145
146 -- for X'Address use Expr
147
148 -- where Expr is of the form Y'Address or recursively is a reference
149 -- to a constant of either of these forms, and X and Y are entities of
150 -- objects, then if Y has a smaller alignment than X, that merits a
151 -- warning about possible bad alignment. The following table collects
152 -- address clauses of this kind. We put these in a table so that they
153 -- can be checked after the back end has completed annotation of the
154 -- alignments of objects, since we can catch more cases that way.
155
156 type Address_Clause_Check_Record is record
157 N : Node_Id;
158 -- The address clause
159
160 X : Entity_Id;
161 -- The entity of the object overlaying Y
162
163 Y : Entity_Id;
164 -- The entity of the object being overlaid
165
166 Off : Boolean;
167 -- Whether the address is offseted within Y
168 end record;
169
170 package Address_Clause_Checks is new Table.Table (
171 Table_Component_Type => Address_Clause_Check_Record,
172 Table_Index_Type => Int,
173 Table_Low_Bound => 1,
174 Table_Initial => 20,
175 Table_Increment => 200,
176 Table_Name => "Address_Clause_Checks");
177
178 -----------------------------------------
179 -- Adjust_Record_For_Reverse_Bit_Order --
180 -----------------------------------------
181
182 procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is
183 Max_Machine_Scalar_Size : constant Uint :=
184 UI_From_Int
185 (Standard_Long_Long_Integer_Size);
186 -- We use this as the maximum machine scalar size in the sense of AI-133
187
188 Num_CC : Natural;
189 Comp : Entity_Id;
190 SSU : constant Uint := UI_From_Int (System_Storage_Unit);
191
192 begin
193 -- This first loop through components does two things. First it deals
194 -- with the case of components with component clauses whose length is
195 -- greater than the maximum machine scalar size (either accepting them
196 -- or rejecting as needed). Second, it counts the number of components
197 -- with component clauses whose length does not exceed this maximum for
198 -- later processing.
199
200 Num_CC := 0;
201 Comp := First_Component_Or_Discriminant (R);
202 while Present (Comp) loop
203 declare
204 CC : constant Node_Id := Component_Clause (Comp);
205
206 begin
207 if Present (CC) then
208 declare
209 Fbit : constant Uint := Static_Integer (First_Bit (CC));
210
211 begin
212 -- Case of component with size > max machine scalar
213
214 if Esize (Comp) > Max_Machine_Scalar_Size then
215
216 -- Must begin on byte boundary
217
218 if Fbit mod SSU /= 0 then
219 Error_Msg_N
220 ("illegal first bit value for reverse bit order",
221 First_Bit (CC));
222 Error_Msg_Uint_1 := SSU;
223 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
224
225 Error_Msg_N
226 ("\must be a multiple of ^ if size greater than ^",
227 First_Bit (CC));
228
229 -- Must end on byte boundary
230
231 elsif Esize (Comp) mod SSU /= 0 then
232 Error_Msg_N
233 ("illegal last bit value for reverse bit order",
234 Last_Bit (CC));
235 Error_Msg_Uint_1 := SSU;
236 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
237
238 Error_Msg_N
239 ("\must be a multiple of ^ if size greater than ^",
240 Last_Bit (CC));
241
242 -- OK, give warning if enabled
243
244 elsif Warn_On_Reverse_Bit_Order then
245 Error_Msg_N
246 ("multi-byte field specified with non-standard"
247 & " Bit_Order?", CC);
248
249 if Bytes_Big_Endian then
250 Error_Msg_N
251 ("\bytes are not reversed "
252 & "(component is big-endian)?", CC);
253 else
254 Error_Msg_N
255 ("\bytes are not reversed "
256 & "(component is little-endian)?", CC);
257 end if;
258 end if;
259
260 -- Case where size is not greater than max machine
261 -- scalar. For now, we just count these.
262
263 else
264 Num_CC := Num_CC + 1;
265 end if;
266 end;
267 end if;
268 end;
269
270 Next_Component_Or_Discriminant (Comp);
271 end loop;
272
273 -- We need to sort the component clauses on the basis of the Position
274 -- values in the clause, so we can group clauses with the same Position.
275 -- together to determine the relevant machine scalar size.
276
277 declare
278 Comps : array (0 .. Num_CC) of Entity_Id;
279 -- Array to collect component and discriminant entities. The data
280 -- starts at index 1, the 0'th entry is for the sort routine.
281
282 function CP_Lt (Op1, Op2 : Natural) return Boolean;
283 -- Compare routine for Sort
284
285 procedure CP_Move (From : Natural; To : Natural);
286 -- Move routine for Sort
287
288 package Sorting is new GNAT.Heap_Sort_G (CP_Move, CP_Lt);
289
290 Start : Natural;
291 Stop : Natural;
292 -- Start and stop positions in component list of set of components
293 -- with the same starting position (that constitute components in
294 -- a single machine scalar).
295
296 MaxL : Uint;
297 -- Maximum last bit value of any component in this set
298
299 MSS : Uint;
300 -- Corresponding machine scalar size
301
302 -----------
303 -- CP_Lt --
304 -----------
305
306 function CP_Lt (Op1, Op2 : Natural) return Boolean is
307 begin
308 return Position (Component_Clause (Comps (Op1))) <
309 Position (Component_Clause (Comps (Op2)));
310 end CP_Lt;
311
312 -------------
313 -- CP_Move --
314 -------------
315
316 procedure CP_Move (From : Natural; To : Natural) is
317 begin
318 Comps (To) := Comps (From);
319 end CP_Move;
320
321 begin
322 -- Collect the component clauses
323
324 Num_CC := 0;
325 Comp := First_Component_Or_Discriminant (R);
326 while Present (Comp) loop
327 if Present (Component_Clause (Comp))
328 and then Esize (Comp) <= Max_Machine_Scalar_Size
329 then
330 Num_CC := Num_CC + 1;
331 Comps (Num_CC) := Comp;
332 end if;
333
334 Next_Component_Or_Discriminant (Comp);
335 end loop;
336
337 -- Sort by ascending position number
338
339 Sorting.Sort (Num_CC);
340
341 -- We now have all the components whose size does not exceed the max
342 -- machine scalar value, sorted by starting position. In this loop
343 -- we gather groups of clauses starting at the same position, to
344 -- process them in accordance with Ada 2005 AI-133.
345
346 Stop := 0;
347 while Stop < Num_CC loop
348 Start := Stop + 1;
349 Stop := Start;
350 MaxL :=
351 Static_Integer (Last_Bit (Component_Clause (Comps (Start))));
352 while Stop < Num_CC loop
353 if Static_Integer
354 (Position (Component_Clause (Comps (Stop + 1)))) =
355 Static_Integer
356 (Position (Component_Clause (Comps (Stop))))
357 then
358 Stop := Stop + 1;
359 MaxL :=
360 UI_Max
361 (MaxL,
362 Static_Integer
363 (Last_Bit (Component_Clause (Comps (Stop)))));
364 else
365 exit;
366 end if;
367 end loop;
368
369 -- Now we have a group of component clauses from Start to Stop
370 -- whose positions are identical, and MaxL is the maximum last bit
371 -- value of any of these components.
372
373 -- We need to determine the corresponding machine scalar size.
374 -- This loop assumes that machine scalar sizes are even, and that
375 -- each possible machine scalar has twice as many bits as the
376 -- next smaller one.
377
378 MSS := Max_Machine_Scalar_Size;
379 while MSS mod 2 = 0
380 and then (MSS / 2) >= SSU
381 and then (MSS / 2) > MaxL
382 loop
383 MSS := MSS / 2;
384 end loop;
385
386 -- Here is where we fix up the Component_Bit_Offset value to
387 -- account for the reverse bit order. Some examples of what needs
388 -- to be done for the case of a machine scalar size of 8 are:
389
390 -- First_Bit .. Last_Bit Component_Bit_Offset
391 -- old new old new
392
393 -- 0 .. 0 7 .. 7 0 7
394 -- 0 .. 1 6 .. 7 0 6
395 -- 0 .. 2 5 .. 7 0 5
396 -- 0 .. 7 0 .. 7 0 4
397
398 -- 1 .. 1 6 .. 6 1 6
399 -- 1 .. 4 3 .. 6 1 3
400 -- 4 .. 7 0 .. 3 4 0
401
402 -- The general rule is that the first bit is obtained by
403 -- subtracting the old ending bit from machine scalar size - 1.
404
405 for C in Start .. Stop loop
406 declare
407 Comp : constant Entity_Id := Comps (C);
408 CC : constant Node_Id := Component_Clause (Comp);
409 LB : constant Uint := Static_Integer (Last_Bit (CC));
410 NFB : constant Uint := MSS - Uint_1 - LB;
411 NLB : constant Uint := NFB + Esize (Comp) - 1;
412 Pos : constant Uint := Static_Integer (Position (CC));
413
414 begin
415 if Warn_On_Reverse_Bit_Order then
416 Error_Msg_Uint_1 := MSS;
417 Error_Msg_N
418 ("info: reverse bit order in machine " &
419 "scalar of length^?", First_Bit (CC));
420 Error_Msg_Uint_1 := NFB;
421 Error_Msg_Uint_2 := NLB;
422
423 if Bytes_Big_Endian then
424 Error_Msg_NE
425 ("?\info: big-endian range for "
426 & "component & is ^ .. ^",
427 First_Bit (CC), Comp);
428 else
429 Error_Msg_NE
430 ("?\info: little-endian range "
431 & "for component & is ^ .. ^",
432 First_Bit (CC), Comp);
433 end if;
434 end if;
435
436 Set_Component_Bit_Offset (Comp, Pos * SSU + NFB);
437 Set_Normalized_First_Bit (Comp, NFB mod SSU);
438 end;
439 end loop;
440 end loop;
441 end;
442 end Adjust_Record_For_Reverse_Bit_Order;
443
444 --------------------------------------
445 -- Alignment_Check_For_Esize_Change --
446 --------------------------------------
447
448 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is
449 begin
450 -- If the alignment is known, and not set by a rep clause, and is
451 -- inconsistent with the size being set, then reset it to unknown,
452 -- we assume in this case that the size overrides the inherited
453 -- alignment, and that the alignment must be recomputed.
454
455 if Known_Alignment (Typ)
456 and then not Has_Alignment_Clause (Typ)
457 and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0
458 then
459 Init_Alignment (Typ);
460 end if;
461 end Alignment_Check_For_Esize_Change;
462
463 -----------------------
464 -- Analyze_At_Clause --
465 -----------------------
466
467 -- An at clause is replaced by the corresponding Address attribute
468 -- definition clause that is the preferred approach in Ada 95.
469
470 procedure Analyze_At_Clause (N : Node_Id) is
471 CS : constant Boolean := Comes_From_Source (N);
472
473 begin
474 -- This is an obsolescent feature
475
476 Check_Restriction (No_Obsolescent_Features, N);
477
478 if Warn_On_Obsolescent_Feature then
479 Error_Msg_N
480 ("at clause is an obsolescent feature (RM J.7(2))?", N);
481 Error_Msg_N
482 ("\use address attribute definition clause instead?", N);
483 end if;
484
485 -- Rewrite as address clause
486
487 Rewrite (N,
488 Make_Attribute_Definition_Clause (Sloc (N),
489 Name => Identifier (N),
490 Chars => Name_Address,
491 Expression => Expression (N)));
492
493 -- We preserve Comes_From_Source, since logically the clause still
494 -- comes from the source program even though it is changed in form.
495
496 Set_Comes_From_Source (N, CS);
497
498 -- Analyze rewritten clause
499
500 Analyze_Attribute_Definition_Clause (N);
501 end Analyze_At_Clause;
502
503 -----------------------------------------
504 -- Analyze_Attribute_Definition_Clause --
505 -----------------------------------------
506
507 procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is
508 Loc : constant Source_Ptr := Sloc (N);
509 Nam : constant Node_Id := Name (N);
510 Attr : constant Name_Id := Chars (N);
511 Expr : constant Node_Id := Expression (N);
512 Id : constant Attribute_Id := Get_Attribute_Id (Attr);
513 Ent : Entity_Id;
514 U_Ent : Entity_Id;
515
516 FOnly : Boolean := False;
517 -- Reset to True for subtype specific attribute (Alignment, Size)
518 -- and for stream attributes, i.e. those cases where in the call
519 -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing
520 -- rules are checked. Note that the case of stream attributes is not
521 -- clear from the RM, but see AI95-00137. Also, the RM seems to
522 -- disallow Storage_Size for derived task types, but that is also
523 -- clearly unintentional.
524
525 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type);
526 -- Common processing for 'Read, 'Write, 'Input and 'Output attribute
527 -- definition clauses.
528
529 -----------------------------------
530 -- Analyze_Stream_TSS_Definition --
531 -----------------------------------
532
533 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type) is
534 Subp : Entity_Id := Empty;
535 I : Interp_Index;
536 It : Interp;
537 Pnam : Entity_Id;
538
539 Is_Read : constant Boolean := (TSS_Nam = TSS_Stream_Read);
540
541 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
542 -- Return true if the entity is a subprogram with an appropriate
543 -- profile for the attribute being defined.
544
545 ----------------------
546 -- Has_Good_Profile --
547 ----------------------
548
549 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
550 F : Entity_Id;
551 Is_Function : constant Boolean := (TSS_Nam = TSS_Stream_Input);
552 Expected_Ekind : constant array (Boolean) of Entity_Kind :=
553 (False => E_Procedure, True => E_Function);
554 Typ : Entity_Id;
555
556 begin
557 if Ekind (Subp) /= Expected_Ekind (Is_Function) then
558 return False;
559 end if;
560
561 F := First_Formal (Subp);
562
563 if No (F)
564 or else Ekind (Etype (F)) /= E_Anonymous_Access_Type
565 or else Designated_Type (Etype (F)) /=
566 Class_Wide_Type (RTE (RE_Root_Stream_Type))
567 then
568 return False;
569 end if;
570
571 if not Is_Function then
572 Next_Formal (F);
573
574 declare
575 Expected_Mode : constant array (Boolean) of Entity_Kind :=
576 (False => E_In_Parameter,
577 True => E_Out_Parameter);
578 begin
579 if Parameter_Mode (F) /= Expected_Mode (Is_Read) then
580 return False;
581 end if;
582 end;
583
584 Typ := Etype (F);
585
586 else
587 Typ := Etype (Subp);
588 end if;
589
590 return Base_Type (Typ) = Base_Type (Ent)
591 and then No (Next_Formal (F));
592 end Has_Good_Profile;
593
594 -- Start of processing for Analyze_Stream_TSS_Definition
595
596 begin
597 FOnly := True;
598
599 if not Is_Type (U_Ent) then
600 Error_Msg_N ("local name must be a subtype", Nam);
601 return;
602 end if;
603
604 Pnam := TSS (Base_Type (U_Ent), TSS_Nam);
605
606 -- If Pnam is present, it can be either inherited from an ancestor
607 -- type (in which case it is legal to redefine it for this type), or
608 -- be a previous definition of the attribute for the same type (in
609 -- which case it is illegal).
610
611 -- In the first case, it will have been analyzed already, and we
612 -- can check that its profile does not match the expected profile
613 -- for a stream attribute of U_Ent. In the second case, either Pnam
614 -- has been analyzed (and has the expected profile), or it has not
615 -- been analyzed yet (case of a type that has not been frozen yet
616 -- and for which the stream attribute has been set using Set_TSS).
617
618 if Present (Pnam)
619 and then (No (First_Entity (Pnam)) or else Has_Good_Profile (Pnam))
620 then
621 Error_Msg_Sloc := Sloc (Pnam);
622 Error_Msg_Name_1 := Attr;
623 Error_Msg_N ("% attribute already defined #", Nam);
624 return;
625 end if;
626
627 Analyze (Expr);
628
629 if Is_Entity_Name (Expr) then
630 if not Is_Overloaded (Expr) then
631 if Has_Good_Profile (Entity (Expr)) then
632 Subp := Entity (Expr);
633 end if;
634
635 else
636 Get_First_Interp (Expr, I, It);
637 while Present (It.Nam) loop
638 if Has_Good_Profile (It.Nam) then
639 Subp := It.Nam;
640 exit;
641 end if;
642
643 Get_Next_Interp (I, It);
644 end loop;
645 end if;
646 end if;
647
648 if Present (Subp) then
649 if Is_Abstract_Subprogram (Subp) then
650 Error_Msg_N ("stream subprogram must not be abstract", Expr);
651 return;
652 end if;
653
654 Set_Entity (Expr, Subp);
655 Set_Etype (Expr, Etype (Subp));
656
657 New_Stream_Subprogram (N, U_Ent, Subp, TSS_Nam);
658
659 else
660 Error_Msg_Name_1 := Attr;
661 Error_Msg_N ("incorrect expression for% attribute", Expr);
662 end if;
663 end Analyze_Stream_TSS_Definition;
664
665 -- Start of processing for Analyze_Attribute_Definition_Clause
666
667 begin
668 -- Process Ignore_Rep_Clauses option
669
670 if Ignore_Rep_Clauses then
671 case Id is
672
673 -- The following should be ignored. They do not affect legality
674 -- and may be target dependent. The basic idea of -gnatI is to
675 -- ignore any rep clauses that may be target dependent but do not
676 -- affect legality (except possibly to be rejected because they
677 -- are incompatible with the compilation target).
678
679 when Attribute_Alignment |
680 Attribute_Bit_Order |
681 Attribute_Component_Size |
682 Attribute_Machine_Radix |
683 Attribute_Object_Size |
684 Attribute_Size |
685 Attribute_Small |
686 Attribute_Stream_Size |
687 Attribute_Value_Size =>
688
689 Rewrite (N, Make_Null_Statement (Sloc (N)));
690 return;
691
692 -- The following should not be ignored, because in the first place
693 -- they are reasonably portable, and should not cause problems in
694 -- compiling code from another target, and also they do affect
695 -- legality, e.g. failing to provide a stream attribute for a
696 -- type may make a program illegal.
697
698 when Attribute_External_Tag |
699 Attribute_Input |
700 Attribute_Output |
701 Attribute_Read |
702 Attribute_Storage_Pool |
703 Attribute_Storage_Size |
704 Attribute_Write =>
705 null;
706
707 -- Other cases are errors, which will be caught below
708
709 when others =>
710 null;
711 end case;
712 end if;
713
714 Analyze (Nam);
715 Ent := Entity (Nam);
716
717 if Rep_Item_Too_Early (Ent, N) then
718 return;
719 end if;
720
721 -- Rep clause applies to full view of incomplete type or private type if
722 -- we have one (if not, this is a premature use of the type). However,
723 -- certain semantic checks need to be done on the specified entity (i.e.
724 -- the private view), so we save it in Ent.
725
726 if Is_Private_Type (Ent)
727 and then Is_Derived_Type (Ent)
728 and then not Is_Tagged_Type (Ent)
729 and then No (Full_View (Ent))
730 then
731 -- If this is a private type whose completion is a derivation from
732 -- another private type, there is no full view, and the attribute
733 -- belongs to the type itself, not its underlying parent.
734
735 U_Ent := Ent;
736
737 elsif Ekind (Ent) = E_Incomplete_Type then
738
739 -- The attribute applies to the full view, set the entity of the
740 -- attribute definition accordingly.
741
742 Ent := Underlying_Type (Ent);
743 U_Ent := Ent;
744 Set_Entity (Nam, Ent);
745
746 else
747 U_Ent := Underlying_Type (Ent);
748 end if;
749
750 -- Complete other routine error checks
751
752 if Etype (Nam) = Any_Type then
753 return;
754
755 elsif Scope (Ent) /= Current_Scope then
756 Error_Msg_N ("entity must be declared in this scope", Nam);
757 return;
758
759 elsif No (U_Ent) then
760 U_Ent := Ent;
761
762 elsif Is_Type (U_Ent)
763 and then not Is_First_Subtype (U_Ent)
764 and then Id /= Attribute_Object_Size
765 and then Id /= Attribute_Value_Size
766 and then not From_At_Mod (N)
767 then
768 Error_Msg_N ("cannot specify attribute for subtype", Nam);
769 return;
770 end if;
771
772 -- Switch on particular attribute
773
774 case Id is
775
776 -------------
777 -- Address --
778 -------------
779
780 -- Address attribute definition clause
781
782 when Attribute_Address => Address : begin
783
784 -- A little error check, catch for X'Address use X'Address;
785
786 if Nkind (Nam) = N_Identifier
787 and then Nkind (Expr) = N_Attribute_Reference
788 and then Attribute_Name (Expr) = Name_Address
789 and then Nkind (Prefix (Expr)) = N_Identifier
790 and then Chars (Nam) = Chars (Prefix (Expr))
791 then
792 Error_Msg_NE
793 ("address for & is self-referencing", Prefix (Expr), Ent);
794 return;
795 end if;
796
797 -- Not that special case, carry on with analysis of expression
798
799 Analyze_And_Resolve (Expr, RTE (RE_Address));
800
801 -- Even when ignoring rep clauses we need to indicate that the
802 -- entity has an address clause and thus it is legal to declare
803 -- it imported.
804
805 if Ignore_Rep_Clauses then
806 if Ekind (U_Ent) = E_Variable
807 or else Ekind (U_Ent) = E_Constant
808 then
809 Record_Rep_Item (U_Ent, N);
810 end if;
811
812 return;
813 end if;
814
815 if Present (Address_Clause (U_Ent)) then
816 Error_Msg_N ("address already given for &", Nam);
817
818 -- Case of address clause for subprogram
819
820 elsif Is_Subprogram (U_Ent) then
821 if Has_Homonym (U_Ent) then
822 Error_Msg_N
823 ("address clause cannot be given " &
824 "for overloaded subprogram",
825 Nam);
826 return;
827 end if;
828
829 -- For subprograms, all address clauses are permitted, and we
830 -- mark the subprogram as having a deferred freeze so that Gigi
831 -- will not elaborate it too soon.
832
833 -- Above needs more comments, what is too soon about???
834
835 Set_Has_Delayed_Freeze (U_Ent);
836
837 -- Case of address clause for entry
838
839 elsif Ekind (U_Ent) = E_Entry then
840 if Nkind (Parent (N)) = N_Task_Body then
841 Error_Msg_N
842 ("entry address must be specified in task spec", Nam);
843 return;
844 end if;
845
846 -- For entries, we require a constant address
847
848 Check_Constant_Address_Clause (Expr, U_Ent);
849
850 -- Special checks for task types
851
852 if Is_Task_Type (Scope (U_Ent))
853 and then Comes_From_Source (Scope (U_Ent))
854 then
855 Error_Msg_N
856 ("?entry address declared for entry in task type", N);
857 Error_Msg_N
858 ("\?only one task can be declared of this type", N);
859 end if;
860
861 -- Entry address clauses are obsolescent
862
863 Check_Restriction (No_Obsolescent_Features, N);
864
865 if Warn_On_Obsolescent_Feature then
866 Error_Msg_N
867 ("attaching interrupt to task entry is an " &
868 "obsolescent feature (RM J.7.1)?", N);
869 Error_Msg_N
870 ("\use interrupt procedure instead?", N);
871 end if;
872
873 -- Case of an address clause for a controlled object which we
874 -- consider to be erroneous.
875
876 elsif Is_Controlled (Etype (U_Ent))
877 or else Has_Controlled_Component (Etype (U_Ent))
878 then
879 Error_Msg_NE
880 ("?controlled object& must not be overlaid", Nam, U_Ent);
881 Error_Msg_N
882 ("\?Program_Error will be raised at run time", Nam);
883 Insert_Action (Declaration_Node (U_Ent),
884 Make_Raise_Program_Error (Loc,
885 Reason => PE_Overlaid_Controlled_Object));
886 return;
887
888 -- Case of address clause for a (non-controlled) object
889
890 elsif
891 Ekind (U_Ent) = E_Variable
892 or else
893 Ekind (U_Ent) = E_Constant
894 then
895 declare
896 Expr : constant Node_Id := Expression (N);
897 O_Ent : Entity_Id;
898 Off : Boolean;
899
900 begin
901 -- Exported variables cannot have an address clause, because
902 -- this cancels the effect of the pragma Export.
903
904 if Is_Exported (U_Ent) then
905 Error_Msg_N
906 ("cannot export object with address clause", Nam);
907 return;
908 end if;
909
910 Find_Overlaid_Entity (N, O_Ent, Off);
911
912 -- Overlaying controlled objects is erroneous
913
914 if Present (O_Ent)
915 and then (Has_Controlled_Component (Etype (O_Ent))
916 or else Is_Controlled (Etype (O_Ent)))
917 then
918 Error_Msg_N
919 ("?cannot overlay with controlled object", Expr);
920 Error_Msg_N
921 ("\?Program_Error will be raised at run time", Expr);
922 Insert_Action (Declaration_Node (U_Ent),
923 Make_Raise_Program_Error (Loc,
924 Reason => PE_Overlaid_Controlled_Object));
925 return;
926
927 elsif Present (O_Ent)
928 and then Ekind (U_Ent) = E_Constant
929 and then not Is_Constant_Object (O_Ent)
930 then
931 Error_Msg_N ("constant overlays a variable?", Expr);
932
933 elsif Present (Renamed_Object (U_Ent)) then
934 Error_Msg_N
935 ("address clause not allowed"
936 & " for a renaming declaration (RM 13.1(6))", Nam);
937 return;
938
939 -- Imported variables can have an address clause, but then
940 -- the import is pretty meaningless except to suppress
941 -- initializations, so we do not need such variables to
942 -- be statically allocated (and in fact it causes trouble
943 -- if the address clause is a local value).
944
945 elsif Is_Imported (U_Ent) then
946 Set_Is_Statically_Allocated (U_Ent, False);
947 end if;
948
949 -- We mark a possible modification of a variable with an
950 -- address clause, since it is likely aliasing is occurring.
951
952 Note_Possible_Modification (Nam, Sure => False);
953
954 -- Here we are checking for explicit overlap of one variable
955 -- by another, and if we find this then mark the overlapped
956 -- variable as also being volatile to prevent unwanted
957 -- optimizations. This is a significant pessimization so
958 -- avoid it when there is an offset, i.e. when the object
959 -- is composite; they cannot be optimized easily anyway.
960
961 if Present (O_Ent)
962 and then Is_Object (O_Ent)
963 and then not Off
964 then
965 Set_Treat_As_Volatile (O_Ent);
966 end if;
967
968 -- Legality checks on the address clause for initialized
969 -- objects is deferred until the freeze point, because
970 -- a subsequent pragma might indicate that the object is
971 -- imported and thus not initialized.
972
973 Set_Has_Delayed_Freeze (U_Ent);
974
975 -- If an initialization call has been generated for this
976 -- object, it needs to be deferred to after the freeze node
977 -- we have just now added, otherwise GIGI will see a
978 -- reference to the variable (as actual to the IP call)
979 -- before its definition.
980
981 declare
982 Init_Call : constant Node_Id := Find_Init_Call (U_Ent, N);
983 begin
984 if Present (Init_Call) then
985 Remove (Init_Call);
986 Append_Freeze_Action (U_Ent, Init_Call);
987 end if;
988 end;
989
990 if Is_Exported (U_Ent) then
991 Error_Msg_N
992 ("& cannot be exported if an address clause is given",
993 Nam);
994 Error_Msg_N
995 ("\define and export a variable " &
996 "that holds its address instead",
997 Nam);
998 end if;
999
1000 -- Entity has delayed freeze, so we will generate an
1001 -- alignment check at the freeze point unless suppressed.
1002
1003 if not Range_Checks_Suppressed (U_Ent)
1004 and then not Alignment_Checks_Suppressed (U_Ent)
1005 then
1006 Set_Check_Address_Alignment (N);
1007 end if;
1008
1009 -- Kill the size check code, since we are not allocating
1010 -- the variable, it is somewhere else.
1011
1012 Kill_Size_Check_Code (U_Ent);
1013
1014 -- If the address clause is of the form:
1015
1016 -- for Y'Address use X'Address
1017
1018 -- or
1019
1020 -- Const : constant Address := X'Address;
1021 -- ...
1022 -- for Y'Address use Const;
1023
1024 -- then we make an entry in the table for checking the size
1025 -- and alignment of the overlaying variable. We defer this
1026 -- check till after code generation to take full advantage
1027 -- of the annotation done by the back end. This entry is
1028 -- only made if the address clause comes from source.
1029
1030 if Address_Clause_Overlay_Warnings
1031 and then Comes_From_Source (N)
1032 and then Present (O_Ent)
1033 and then Is_Object (O_Ent)
1034 then
1035 Address_Clause_Checks.Append ((N, U_Ent, O_Ent, Off));
1036
1037 -- If variable overlays a constant view, and we are
1038 -- warning on overlays, then mark the variable as
1039 -- overlaying a constant (we will give warnings later
1040 -- if this variable is assigned).
1041
1042 if Is_Constant_Object (O_Ent)
1043 and then Ekind (U_Ent) = E_Variable
1044 then
1045 Set_Overlays_Constant (U_Ent);
1046 end if;
1047 end if;
1048 end;
1049
1050 -- Not a valid entity for an address clause
1051
1052 else
1053 Error_Msg_N ("address cannot be given for &", Nam);
1054 end if;
1055 end Address;
1056
1057 ---------------
1058 -- Alignment --
1059 ---------------
1060
1061 -- Alignment attribute definition clause
1062
1063 when Attribute_Alignment => Alignment : declare
1064 Align : constant Uint := Get_Alignment_Value (Expr);
1065
1066 begin
1067 FOnly := True;
1068
1069 if not Is_Type (U_Ent)
1070 and then Ekind (U_Ent) /= E_Variable
1071 and then Ekind (U_Ent) /= E_Constant
1072 then
1073 Error_Msg_N ("alignment cannot be given for &", Nam);
1074
1075 elsif Has_Alignment_Clause (U_Ent) then
1076 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1077 Error_Msg_N ("alignment clause previously given#", N);
1078
1079 elsif Align /= No_Uint then
1080 Set_Has_Alignment_Clause (U_Ent);
1081 Set_Alignment (U_Ent, Align);
1082
1083 -- For an array type, U_Ent is the first subtype. In that case,
1084 -- also set the alignment of the anonymous base type so that
1085 -- other subtypes (such as the itypes for aggregates of the
1086 -- type) also receive the expected alignment.
1087
1088 if Is_Array_Type (U_Ent) then
1089 Set_Alignment (Base_Type (U_Ent), Align);
1090 end if;
1091 end if;
1092 end Alignment;
1093
1094 ---------------
1095 -- Bit_Order --
1096 ---------------
1097
1098 -- Bit_Order attribute definition clause
1099
1100 when Attribute_Bit_Order => Bit_Order : declare
1101 begin
1102 if not Is_Record_Type (U_Ent) then
1103 Error_Msg_N
1104 ("Bit_Order can only be defined for record type", Nam);
1105
1106 else
1107 Analyze_And_Resolve (Expr, RTE (RE_Bit_Order));
1108
1109 if Etype (Expr) = Any_Type then
1110 return;
1111
1112 elsif not Is_Static_Expression (Expr) then
1113 Flag_Non_Static_Expr
1114 ("Bit_Order requires static expression!", Expr);
1115
1116 else
1117 if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then
1118 Set_Reverse_Bit_Order (U_Ent, True);
1119 end if;
1120 end if;
1121 end if;
1122 end Bit_Order;
1123
1124 --------------------
1125 -- Component_Size --
1126 --------------------
1127
1128 -- Component_Size attribute definition clause
1129
1130 when Attribute_Component_Size => Component_Size_Case : declare
1131 Csize : constant Uint := Static_Integer (Expr);
1132 Btype : Entity_Id;
1133 Biased : Boolean;
1134 New_Ctyp : Entity_Id;
1135 Decl : Node_Id;
1136
1137 begin
1138 if not Is_Array_Type (U_Ent) then
1139 Error_Msg_N ("component size requires array type", Nam);
1140 return;
1141 end if;
1142
1143 Btype := Base_Type (U_Ent);
1144
1145 if Has_Component_Size_Clause (Btype) then
1146 Error_Msg_N
1147 ("component size clause for& previously given", Nam);
1148
1149 elsif Csize /= No_Uint then
1150 Check_Size (Expr, Component_Type (Btype), Csize, Biased);
1151
1152 if Has_Aliased_Components (Btype)
1153 and then Csize < 32
1154 and then Csize /= 8
1155 and then Csize /= 16
1156 then
1157 Error_Msg_N
1158 ("component size incorrect for aliased components", N);
1159 return;
1160 end if;
1161
1162 -- For the biased case, build a declaration for a subtype
1163 -- that will be used to represent the biased subtype that
1164 -- reflects the biased representation of components. We need
1165 -- this subtype to get proper conversions on referencing
1166 -- elements of the array. Note that component size clauses
1167 -- are ignored in VM mode.
1168
1169 if VM_Target = No_VM then
1170 if Biased then
1171 New_Ctyp :=
1172 Make_Defining_Identifier (Loc,
1173 Chars =>
1174 New_External_Name (Chars (U_Ent), 'C', 0, 'T'));
1175
1176 Decl :=
1177 Make_Subtype_Declaration (Loc,
1178 Defining_Identifier => New_Ctyp,
1179 Subtype_Indication =>
1180 New_Occurrence_Of (Component_Type (Btype), Loc));
1181
1182 Set_Parent (Decl, N);
1183 Analyze (Decl, Suppress => All_Checks);
1184
1185 Set_Has_Delayed_Freeze (New_Ctyp, False);
1186 Set_Esize (New_Ctyp, Csize);
1187 Set_RM_Size (New_Ctyp, Csize);
1188 Init_Alignment (New_Ctyp);
1189 Set_Has_Biased_Representation (New_Ctyp, True);
1190 Set_Is_Itype (New_Ctyp, True);
1191 Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
1192
1193 Set_Component_Type (Btype, New_Ctyp);
1194
1195 if Warn_On_Biased_Representation then
1196 Error_Msg_N
1197 ("?component size clause forces biased "
1198 & "representation", N);
1199 end if;
1200 end if;
1201
1202 Set_Component_Size (Btype, Csize);
1203
1204 -- For VM case, we ignore component size clauses
1205
1206 else
1207 -- Give a warning unless we are in GNAT mode, in which case
1208 -- the warning is suppressed since it is not useful.
1209
1210 if not GNAT_Mode then
1211 Error_Msg_N
1212 ("?component size ignored in this configuration", N);
1213 end if;
1214 end if;
1215
1216 Set_Has_Component_Size_Clause (Btype, True);
1217 Set_Has_Non_Standard_Rep (Btype, True);
1218 end if;
1219 end Component_Size_Case;
1220
1221 ------------------
1222 -- External_Tag --
1223 ------------------
1224
1225 when Attribute_External_Tag => External_Tag :
1226 begin
1227 if not Is_Tagged_Type (U_Ent) then
1228 Error_Msg_N ("should be a tagged type", Nam);
1229 end if;
1230
1231 Analyze_And_Resolve (Expr, Standard_String);
1232
1233 if not Is_Static_Expression (Expr) then
1234 Flag_Non_Static_Expr
1235 ("static string required for tag name!", Nam);
1236 end if;
1237
1238 if VM_Target = No_VM then
1239 Set_Has_External_Tag_Rep_Clause (U_Ent);
1240 else
1241 Error_Msg_Name_1 := Attr;
1242 Error_Msg_N
1243 ("% attribute unsupported in this configuration", Nam);
1244 end if;
1245
1246 if not Is_Library_Level_Entity (U_Ent) then
1247 Error_Msg_NE
1248 ("?non-unique external tag supplied for &", N, U_Ent);
1249 Error_Msg_N
1250 ("?\same external tag applies to all subprogram calls", N);
1251 Error_Msg_N
1252 ("?\corresponding internal tag cannot be obtained", N);
1253 end if;
1254 end External_Tag;
1255
1256 -----------
1257 -- Input --
1258 -----------
1259
1260 when Attribute_Input =>
1261 Analyze_Stream_TSS_Definition (TSS_Stream_Input);
1262 Set_Has_Specified_Stream_Input (Ent);
1263
1264 -------------------
1265 -- Machine_Radix --
1266 -------------------
1267
1268 -- Machine radix attribute definition clause
1269
1270 when Attribute_Machine_Radix => Machine_Radix : declare
1271 Radix : constant Uint := Static_Integer (Expr);
1272
1273 begin
1274 if not Is_Decimal_Fixed_Point_Type (U_Ent) then
1275 Error_Msg_N ("decimal fixed-point type expected for &", Nam);
1276
1277 elsif Has_Machine_Radix_Clause (U_Ent) then
1278 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1279 Error_Msg_N ("machine radix clause previously given#", N);
1280
1281 elsif Radix /= No_Uint then
1282 Set_Has_Machine_Radix_Clause (U_Ent);
1283 Set_Has_Non_Standard_Rep (Base_Type (U_Ent));
1284
1285 if Radix = 2 then
1286 null;
1287 elsif Radix = 10 then
1288 Set_Machine_Radix_10 (U_Ent);
1289 else
1290 Error_Msg_N ("machine radix value must be 2 or 10", Expr);
1291 end if;
1292 end if;
1293 end Machine_Radix;
1294
1295 -----------------
1296 -- Object_Size --
1297 -----------------
1298
1299 -- Object_Size attribute definition clause
1300
1301 when Attribute_Object_Size => Object_Size : declare
1302 Size : constant Uint := Static_Integer (Expr);
1303
1304 Biased : Boolean;
1305 pragma Warnings (Off, Biased);
1306
1307 begin
1308 if not Is_Type (U_Ent) then
1309 Error_Msg_N ("Object_Size cannot be given for &", Nam);
1310
1311 elsif Has_Object_Size_Clause (U_Ent) then
1312 Error_Msg_N ("Object_Size already given for &", Nam);
1313
1314 else
1315 Check_Size (Expr, U_Ent, Size, Biased);
1316
1317 if Size /= 8
1318 and then
1319 Size /= 16
1320 and then
1321 Size /= 32
1322 and then
1323 UI_Mod (Size, 64) /= 0
1324 then
1325 Error_Msg_N
1326 ("Object_Size must be 8, 16, 32, or multiple of 64",
1327 Expr);
1328 end if;
1329
1330 Set_Esize (U_Ent, Size);
1331 Set_Has_Object_Size_Clause (U_Ent);
1332 Alignment_Check_For_Esize_Change (U_Ent);
1333 end if;
1334 end Object_Size;
1335
1336 ------------
1337 -- Output --
1338 ------------
1339
1340 when Attribute_Output =>
1341 Analyze_Stream_TSS_Definition (TSS_Stream_Output);
1342 Set_Has_Specified_Stream_Output (Ent);
1343
1344 ----------
1345 -- Read --
1346 ----------
1347
1348 when Attribute_Read =>
1349 Analyze_Stream_TSS_Definition (TSS_Stream_Read);
1350 Set_Has_Specified_Stream_Read (Ent);
1351
1352 ----------
1353 -- Size --
1354 ----------
1355
1356 -- Size attribute definition clause
1357
1358 when Attribute_Size => Size : declare
1359 Size : constant Uint := Static_Integer (Expr);
1360 Etyp : Entity_Id;
1361 Biased : Boolean;
1362
1363 begin
1364 FOnly := True;
1365
1366 if Has_Size_Clause (U_Ent) then
1367 Error_Msg_N ("size already given for &", Nam);
1368
1369 elsif not Is_Type (U_Ent)
1370 and then Ekind (U_Ent) /= E_Variable
1371 and then Ekind (U_Ent) /= E_Constant
1372 then
1373 Error_Msg_N ("size cannot be given for &", Nam);
1374
1375 elsif Is_Array_Type (U_Ent)
1376 and then not Is_Constrained (U_Ent)
1377 then
1378 Error_Msg_N
1379 ("size cannot be given for unconstrained array", Nam);
1380
1381 elsif Size /= No_Uint then
1382 if Is_Type (U_Ent) then
1383 Etyp := U_Ent;
1384 else
1385 Etyp := Etype (U_Ent);
1386 end if;
1387
1388 -- Check size, note that Gigi is in charge of checking that the
1389 -- size of an array or record type is OK. Also we do not check
1390 -- the size in the ordinary fixed-point case, since it is too
1391 -- early to do so (there may be subsequent small clause that
1392 -- affects the size). We can check the size if a small clause
1393 -- has already been given.
1394
1395 if not Is_Ordinary_Fixed_Point_Type (U_Ent)
1396 or else Has_Small_Clause (U_Ent)
1397 then
1398 Check_Size (Expr, Etyp, Size, Biased);
1399 Set_Has_Biased_Representation (U_Ent, Biased);
1400
1401 if Biased and Warn_On_Biased_Representation then
1402 Error_Msg_N
1403 ("?size clause forces biased representation", N);
1404 end if;
1405 end if;
1406
1407 -- For types set RM_Size and Esize if possible
1408
1409 if Is_Type (U_Ent) then
1410 Set_RM_Size (U_Ent, Size);
1411
1412 -- For scalar types, increase Object_Size to power of 2, but
1413 -- not less than a storage unit in any case (i.e., normally
1414 -- this means it will be byte addressable).
1415
1416 if Is_Scalar_Type (U_Ent) then
1417 if Size <= System_Storage_Unit then
1418 Init_Esize (U_Ent, System_Storage_Unit);
1419 elsif Size <= 16 then
1420 Init_Esize (U_Ent, 16);
1421 elsif Size <= 32 then
1422 Init_Esize (U_Ent, 32);
1423 else
1424 Set_Esize (U_Ent, (Size + 63) / 64 * 64);
1425 end if;
1426
1427 -- For all other types, object size = value size. The
1428 -- backend will adjust as needed.
1429
1430 else
1431 Set_Esize (U_Ent, Size);
1432 end if;
1433
1434 Alignment_Check_For_Esize_Change (U_Ent);
1435
1436 -- For objects, set Esize only
1437
1438 else
1439 if Is_Elementary_Type (Etyp) then
1440 if Size /= System_Storage_Unit
1441 and then
1442 Size /= System_Storage_Unit * 2
1443 and then
1444 Size /= System_Storage_Unit * 4
1445 and then
1446 Size /= System_Storage_Unit * 8
1447 then
1448 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1449 Error_Msg_Uint_2 := Error_Msg_Uint_1 * 8;
1450 Error_Msg_N
1451 ("size for primitive object must be a power of 2"
1452 & " in the range ^-^", N);
1453 end if;
1454 end if;
1455
1456 Set_Esize (U_Ent, Size);
1457 end if;
1458
1459 Set_Has_Size_Clause (U_Ent);
1460 end if;
1461 end Size;
1462
1463 -----------
1464 -- Small --
1465 -----------
1466
1467 -- Small attribute definition clause
1468
1469 when Attribute_Small => Small : declare
1470 Implicit_Base : constant Entity_Id := Base_Type (U_Ent);
1471 Small : Ureal;
1472
1473 begin
1474 Analyze_And_Resolve (Expr, Any_Real);
1475
1476 if Etype (Expr) = Any_Type then
1477 return;
1478
1479 elsif not Is_Static_Expression (Expr) then
1480 Flag_Non_Static_Expr
1481 ("small requires static expression!", Expr);
1482 return;
1483
1484 else
1485 Small := Expr_Value_R (Expr);
1486
1487 if Small <= Ureal_0 then
1488 Error_Msg_N ("small value must be greater than zero", Expr);
1489 return;
1490 end if;
1491
1492 end if;
1493
1494 if not Is_Ordinary_Fixed_Point_Type (U_Ent) then
1495 Error_Msg_N
1496 ("small requires an ordinary fixed point type", Nam);
1497
1498 elsif Has_Small_Clause (U_Ent) then
1499 Error_Msg_N ("small already given for &", Nam);
1500
1501 elsif Small > Delta_Value (U_Ent) then
1502 Error_Msg_N
1503 ("small value must not be greater then delta value", Nam);
1504
1505 else
1506 Set_Small_Value (U_Ent, Small);
1507 Set_Small_Value (Implicit_Base, Small);
1508 Set_Has_Small_Clause (U_Ent);
1509 Set_Has_Small_Clause (Implicit_Base);
1510 Set_Has_Non_Standard_Rep (Implicit_Base);
1511 end if;
1512 end Small;
1513
1514 ------------------
1515 -- Storage_Pool --
1516 ------------------
1517
1518 -- Storage_Pool attribute definition clause
1519
1520 when Attribute_Storage_Pool => Storage_Pool : declare
1521 Pool : Entity_Id;
1522 T : Entity_Id;
1523
1524 begin
1525 if Ekind (U_Ent) = E_Access_Subprogram_Type then
1526 Error_Msg_N
1527 ("storage pool cannot be given for access-to-subprogram type",
1528 Nam);
1529 return;
1530
1531 elsif Ekind (U_Ent) /= E_Access_Type
1532 and then Ekind (U_Ent) /= E_General_Access_Type
1533 then
1534 Error_Msg_N
1535 ("storage pool can only be given for access types", Nam);
1536 return;
1537
1538 elsif Is_Derived_Type (U_Ent) then
1539 Error_Msg_N
1540 ("storage pool cannot be given for a derived access type",
1541 Nam);
1542
1543 elsif Has_Storage_Size_Clause (U_Ent) then
1544 Error_Msg_N ("storage size already given for &", Nam);
1545 return;
1546
1547 elsif Present (Associated_Storage_Pool (U_Ent)) then
1548 Error_Msg_N ("storage pool already given for &", Nam);
1549 return;
1550 end if;
1551
1552 Analyze_And_Resolve
1553 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1554
1555 if not Denotes_Variable (Expr) then
1556 Error_Msg_N ("storage pool must be a variable", Expr);
1557 return;
1558 end if;
1559
1560 if Nkind (Expr) = N_Type_Conversion then
1561 T := Etype (Expression (Expr));
1562 else
1563 T := Etype (Expr);
1564 end if;
1565
1566 -- The Stack_Bounded_Pool is used internally for implementing
1567 -- access types with a Storage_Size. Since it only work
1568 -- properly when used on one specific type, we need to check
1569 -- that it is not hijacked improperly:
1570 -- type T is access Integer;
1571 -- for T'Storage_Size use n;
1572 -- type Q is access Float;
1573 -- for Q'Storage_Size use T'Storage_Size; -- incorrect
1574
1575 if RTE_Available (RE_Stack_Bounded_Pool)
1576 and then Base_Type (T) = RTE (RE_Stack_Bounded_Pool)
1577 then
1578 Error_Msg_N ("non-shareable internal Pool", Expr);
1579 return;
1580 end if;
1581
1582 -- If the argument is a name that is not an entity name, then
1583 -- we construct a renaming operation to define an entity of
1584 -- type storage pool.
1585
1586 if not Is_Entity_Name (Expr)
1587 and then Is_Object_Reference (Expr)
1588 then
1589 Pool :=
1590 Make_Defining_Identifier (Loc,
1591 Chars => New_Internal_Name ('P'));
1592
1593 declare
1594 Rnode : constant Node_Id :=
1595 Make_Object_Renaming_Declaration (Loc,
1596 Defining_Identifier => Pool,
1597 Subtype_Mark =>
1598 New_Occurrence_Of (Etype (Expr), Loc),
1599 Name => Expr);
1600
1601 begin
1602 Insert_Before (N, Rnode);
1603 Analyze (Rnode);
1604 Set_Associated_Storage_Pool (U_Ent, Pool);
1605 end;
1606
1607 elsif Is_Entity_Name (Expr) then
1608 Pool := Entity (Expr);
1609
1610 -- If pool is a renamed object, get original one. This can
1611 -- happen with an explicit renaming, and within instances.
1612
1613 while Present (Renamed_Object (Pool))
1614 and then Is_Entity_Name (Renamed_Object (Pool))
1615 loop
1616 Pool := Entity (Renamed_Object (Pool));
1617 end loop;
1618
1619 if Present (Renamed_Object (Pool))
1620 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1621 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1622 then
1623 Pool := Entity (Expression (Renamed_Object (Pool)));
1624 end if;
1625
1626 Set_Associated_Storage_Pool (U_Ent, Pool);
1627
1628 elsif Nkind (Expr) = N_Type_Conversion
1629 and then Is_Entity_Name (Expression (Expr))
1630 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1631 then
1632 Pool := Entity (Expression (Expr));
1633 Set_Associated_Storage_Pool (U_Ent, Pool);
1634
1635 else
1636 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1637 return;
1638 end if;
1639 end Storage_Pool;
1640
1641 ------------------
1642 -- Storage_Size --
1643 ------------------
1644
1645 -- Storage_Size attribute definition clause
1646
1647 when Attribute_Storage_Size => Storage_Size : declare
1648 Btype : constant Entity_Id := Base_Type (U_Ent);
1649 Sprag : Node_Id;
1650
1651 begin
1652 if Is_Task_Type (U_Ent) then
1653 Check_Restriction (No_Obsolescent_Features, N);
1654
1655 if Warn_On_Obsolescent_Feature then
1656 Error_Msg_N
1657 ("storage size clause for task is an " &
1658 "obsolescent feature (RM J.9)?", N);
1659 Error_Msg_N
1660 ("\use Storage_Size pragma instead?", N);
1661 end if;
1662
1663 FOnly := True;
1664 end if;
1665
1666 if not Is_Access_Type (U_Ent)
1667 and then Ekind (U_Ent) /= E_Task_Type
1668 then
1669 Error_Msg_N ("storage size cannot be given for &", Nam);
1670
1671 elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then
1672 Error_Msg_N
1673 ("storage size cannot be given for a derived access type",
1674 Nam);
1675
1676 elsif Has_Storage_Size_Clause (Btype) then
1677 Error_Msg_N ("storage size already given for &", Nam);
1678
1679 else
1680 Analyze_And_Resolve (Expr, Any_Integer);
1681
1682 if Is_Access_Type (U_Ent) then
1683 if Present (Associated_Storage_Pool (U_Ent)) then
1684 Error_Msg_N ("storage pool already given for &", Nam);
1685 return;
1686 end if;
1687
1688 if Compile_Time_Known_Value (Expr)
1689 and then Expr_Value (Expr) = 0
1690 then
1691 Set_No_Pool_Assigned (Btype);
1692 end if;
1693
1694 else -- Is_Task_Type (U_Ent)
1695 Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size);
1696
1697 if Present (Sprag) then
1698 Error_Msg_Sloc := Sloc (Sprag);
1699 Error_Msg_N
1700 ("Storage_Size already specified#", Nam);
1701 return;
1702 end if;
1703 end if;
1704
1705 Set_Has_Storage_Size_Clause (Btype);
1706 end if;
1707 end Storage_Size;
1708
1709 -----------------
1710 -- Stream_Size --
1711 -----------------
1712
1713 when Attribute_Stream_Size => Stream_Size : declare
1714 Size : constant Uint := Static_Integer (Expr);
1715
1716 begin
1717 if Ada_Version <= Ada_95 then
1718 Check_Restriction (No_Implementation_Attributes, N);
1719 end if;
1720
1721 if Has_Stream_Size_Clause (U_Ent) then
1722 Error_Msg_N ("Stream_Size already given for &", Nam);
1723
1724 elsif Is_Elementary_Type (U_Ent) then
1725 if Size /= System_Storage_Unit
1726 and then
1727 Size /= System_Storage_Unit * 2
1728 and then
1729 Size /= System_Storage_Unit * 4
1730 and then
1731 Size /= System_Storage_Unit * 8
1732 then
1733 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1734 Error_Msg_N
1735 ("stream size for elementary type must be a"
1736 & " power of 2 and at least ^", N);
1737
1738 elsif RM_Size (U_Ent) > Size then
1739 Error_Msg_Uint_1 := RM_Size (U_Ent);
1740 Error_Msg_N
1741 ("stream size for elementary type must be a"
1742 & " power of 2 and at least ^", N);
1743 end if;
1744
1745 Set_Has_Stream_Size_Clause (U_Ent);
1746
1747 else
1748 Error_Msg_N ("Stream_Size cannot be given for &", Nam);
1749 end if;
1750 end Stream_Size;
1751
1752 ----------------
1753 -- Value_Size --
1754 ----------------
1755
1756 -- Value_Size attribute definition clause
1757
1758 when Attribute_Value_Size => Value_Size : declare
1759 Size : constant Uint := Static_Integer (Expr);
1760 Biased : Boolean;
1761
1762 begin
1763 if not Is_Type (U_Ent) then
1764 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1765
1766 elsif Present
1767 (Get_Attribute_Definition_Clause
1768 (U_Ent, Attribute_Value_Size))
1769 then
1770 Error_Msg_N ("Value_Size already given for &", Nam);
1771
1772 elsif Is_Array_Type (U_Ent)
1773 and then not Is_Constrained (U_Ent)
1774 then
1775 Error_Msg_N
1776 ("Value_Size cannot be given for unconstrained array", Nam);
1777
1778 else
1779 if Is_Elementary_Type (U_Ent) then
1780 Check_Size (Expr, U_Ent, Size, Biased);
1781 Set_Has_Biased_Representation (U_Ent, Biased);
1782
1783 if Biased and Warn_On_Biased_Representation then
1784 Error_Msg_N
1785 ("?value size clause forces biased representation", N);
1786 end if;
1787 end if;
1788
1789 Set_RM_Size (U_Ent, Size);
1790 end if;
1791 end Value_Size;
1792
1793 -----------
1794 -- Write --
1795 -----------
1796
1797 when Attribute_Write =>
1798 Analyze_Stream_TSS_Definition (TSS_Stream_Write);
1799 Set_Has_Specified_Stream_Write (Ent);
1800
1801 -- All other attributes cannot be set
1802
1803 when others =>
1804 Error_Msg_N
1805 ("attribute& cannot be set with definition clause", N);
1806 end case;
1807
1808 -- The test for the type being frozen must be performed after
1809 -- any expression the clause has been analyzed since the expression
1810 -- itself might cause freezing that makes the clause illegal.
1811
1812 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1813 return;
1814 end if;
1815 end Analyze_Attribute_Definition_Clause;
1816
1817 ----------------------------
1818 -- Analyze_Code_Statement --
1819 ----------------------------
1820
1821 procedure Analyze_Code_Statement (N : Node_Id) is
1822 HSS : constant Node_Id := Parent (N);
1823 SBody : constant Node_Id := Parent (HSS);
1824 Subp : constant Entity_Id := Current_Scope;
1825 Stmt : Node_Id;
1826 Decl : Node_Id;
1827 StmtO : Node_Id;
1828 DeclO : Node_Id;
1829
1830 begin
1831 -- Analyze and check we get right type, note that this implements the
1832 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1833 -- is the only way that Asm_Insn could possibly be visible.
1834
1835 Analyze_And_Resolve (Expression (N));
1836
1837 if Etype (Expression (N)) = Any_Type then
1838 return;
1839 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1840 Error_Msg_N ("incorrect type for code statement", N);
1841 return;
1842 end if;
1843
1844 Check_Code_Statement (N);
1845
1846 -- Make sure we appear in the handled statement sequence of a
1847 -- subprogram (RM 13.8(3)).
1848
1849 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1850 or else Nkind (SBody) /= N_Subprogram_Body
1851 then
1852 Error_Msg_N
1853 ("code statement can only appear in body of subprogram", N);
1854 return;
1855 end if;
1856
1857 -- Do remaining checks (RM 13.8(3)) if not already done
1858
1859 if not Is_Machine_Code_Subprogram (Subp) then
1860 Set_Is_Machine_Code_Subprogram (Subp);
1861
1862 -- No exception handlers allowed
1863
1864 if Present (Exception_Handlers (HSS)) then
1865 Error_Msg_N
1866 ("exception handlers not permitted in machine code subprogram",
1867 First (Exception_Handlers (HSS)));
1868 end if;
1869
1870 -- No declarations other than use clauses and pragmas (we allow
1871 -- certain internally generated declarations as well).
1872
1873 Decl := First (Declarations (SBody));
1874 while Present (Decl) loop
1875 DeclO := Original_Node (Decl);
1876 if Comes_From_Source (DeclO)
1877 and not Nkind_In (DeclO, N_Pragma,
1878 N_Use_Package_Clause,
1879 N_Use_Type_Clause,
1880 N_Implicit_Label_Declaration)
1881 then
1882 Error_Msg_N
1883 ("this declaration not allowed in machine code subprogram",
1884 DeclO);
1885 end if;
1886
1887 Next (Decl);
1888 end loop;
1889
1890 -- No statements other than code statements, pragmas, and labels.
1891 -- Again we allow certain internally generated statements.
1892
1893 Stmt := First (Statements (HSS));
1894 while Present (Stmt) loop
1895 StmtO := Original_Node (Stmt);
1896 if Comes_From_Source (StmtO)
1897 and then not Nkind_In (StmtO, N_Pragma,
1898 N_Label,
1899 N_Code_Statement)
1900 then
1901 Error_Msg_N
1902 ("this statement is not allowed in machine code subprogram",
1903 StmtO);
1904 end if;
1905
1906 Next (Stmt);
1907 end loop;
1908 end if;
1909 end Analyze_Code_Statement;
1910
1911 -----------------------------------------------
1912 -- Analyze_Enumeration_Representation_Clause --
1913 -----------------------------------------------
1914
1915 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1916 Ident : constant Node_Id := Identifier (N);
1917 Aggr : constant Node_Id := Array_Aggregate (N);
1918 Enumtype : Entity_Id;
1919 Elit : Entity_Id;
1920 Expr : Node_Id;
1921 Assoc : Node_Id;
1922 Choice : Node_Id;
1923 Val : Uint;
1924 Err : Boolean := False;
1925
1926 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1927 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1928 Min : Uint;
1929 Max : Uint;
1930
1931 begin
1932 if Ignore_Rep_Clauses then
1933 return;
1934 end if;
1935
1936 -- First some basic error checks
1937
1938 Find_Type (Ident);
1939 Enumtype := Entity (Ident);
1940
1941 if Enumtype = Any_Type
1942 or else Rep_Item_Too_Early (Enumtype, N)
1943 then
1944 return;
1945 else
1946 Enumtype := Underlying_Type (Enumtype);
1947 end if;
1948
1949 if not Is_Enumeration_Type (Enumtype) then
1950 Error_Msg_NE
1951 ("enumeration type required, found}",
1952 Ident, First_Subtype (Enumtype));
1953 return;
1954 end if;
1955
1956 -- Ignore rep clause on generic actual type. This will already have
1957 -- been flagged on the template as an error, and this is the safest
1958 -- way to ensure we don't get a junk cascaded message in the instance.
1959
1960 if Is_Generic_Actual_Type (Enumtype) then
1961 return;
1962
1963 -- Type must be in current scope
1964
1965 elsif Scope (Enumtype) /= Current_Scope then
1966 Error_Msg_N ("type must be declared in this scope", Ident);
1967 return;
1968
1969 -- Type must be a first subtype
1970
1971 elsif not Is_First_Subtype (Enumtype) then
1972 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1973 return;
1974
1975 -- Ignore duplicate rep clause
1976
1977 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1978 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1979 return;
1980
1981 -- Don't allow rep clause for standard [wide_[wide_]]character
1982
1983 elsif Is_Standard_Character_Type (Enumtype) then
1984 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1985 return;
1986
1987 -- Check that the expression is a proper aggregate (no parentheses)
1988
1989 elsif Paren_Count (Aggr) /= 0 then
1990 Error_Msg
1991 ("extra parentheses surrounding aggregate not allowed",
1992 First_Sloc (Aggr));
1993 return;
1994
1995 -- All tests passed, so set rep clause in place
1996
1997 else
1998 Set_Has_Enumeration_Rep_Clause (Enumtype);
1999 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
2000 end if;
2001
2002 -- Now we process the aggregate. Note that we don't use the normal
2003 -- aggregate code for this purpose, because we don't want any of the
2004 -- normal expansion activities, and a number of special semantic
2005 -- rules apply (including the component type being any integer type)
2006
2007 Elit := First_Literal (Enumtype);
2008
2009 -- First the positional entries if any
2010
2011 if Present (Expressions (Aggr)) then
2012 Expr := First (Expressions (Aggr));
2013 while Present (Expr) loop
2014 if No (Elit) then
2015 Error_Msg_N ("too many entries in aggregate", Expr);
2016 return;
2017 end if;
2018
2019 Val := Static_Integer (Expr);
2020
2021 -- Err signals that we found some incorrect entries processing
2022 -- the list. The final checks for completeness and ordering are
2023 -- skipped in this case.
2024
2025 if Val = No_Uint then
2026 Err := True;
2027 elsif Val < Lo or else Hi < Val then
2028 Error_Msg_N ("value outside permitted range", Expr);
2029 Err := True;
2030 end if;
2031
2032 Set_Enumeration_Rep (Elit, Val);
2033 Set_Enumeration_Rep_Expr (Elit, Expr);
2034 Next (Expr);
2035 Next (Elit);
2036 end loop;
2037 end if;
2038
2039 -- Now process the named entries if present
2040
2041 if Present (Component_Associations (Aggr)) then
2042 Assoc := First (Component_Associations (Aggr));
2043 while Present (Assoc) loop
2044 Choice := First (Choices (Assoc));
2045
2046 if Present (Next (Choice)) then
2047 Error_Msg_N
2048 ("multiple choice not allowed here", Next (Choice));
2049 Err := True;
2050 end if;
2051
2052 if Nkind (Choice) = N_Others_Choice then
2053 Error_Msg_N ("others choice not allowed here", Choice);
2054 Err := True;
2055
2056 elsif Nkind (Choice) = N_Range then
2057 -- ??? should allow zero/one element range here
2058 Error_Msg_N ("range not allowed here", Choice);
2059 Err := True;
2060
2061 else
2062 Analyze_And_Resolve (Choice, Enumtype);
2063
2064 if Is_Entity_Name (Choice)
2065 and then Is_Type (Entity (Choice))
2066 then
2067 Error_Msg_N ("subtype name not allowed here", Choice);
2068 Err := True;
2069 -- ??? should allow static subtype with zero/one entry
2070
2071 elsif Etype (Choice) = Base_Type (Enumtype) then
2072 if not Is_Static_Expression (Choice) then
2073 Flag_Non_Static_Expr
2074 ("non-static expression used for choice!", Choice);
2075 Err := True;
2076
2077 else
2078 Elit := Expr_Value_E (Choice);
2079
2080 if Present (Enumeration_Rep_Expr (Elit)) then
2081 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
2082 Error_Msg_NE
2083 ("representation for& previously given#",
2084 Choice, Elit);
2085 Err := True;
2086 end if;
2087
2088 Set_Enumeration_Rep_Expr (Elit, Choice);
2089
2090 Expr := Expression (Assoc);
2091 Val := Static_Integer (Expr);
2092
2093 if Val = No_Uint then
2094 Err := True;
2095
2096 elsif Val < Lo or else Hi < Val then
2097 Error_Msg_N ("value outside permitted range", Expr);
2098 Err := True;
2099 end if;
2100
2101 Set_Enumeration_Rep (Elit, Val);
2102 end if;
2103 end if;
2104 end if;
2105
2106 Next (Assoc);
2107 end loop;
2108 end if;
2109
2110 -- Aggregate is fully processed. Now we check that a full set of
2111 -- representations was given, and that they are in range and in order.
2112 -- These checks are only done if no other errors occurred.
2113
2114 if not Err then
2115 Min := No_Uint;
2116 Max := No_Uint;
2117
2118 Elit := First_Literal (Enumtype);
2119 while Present (Elit) loop
2120 if No (Enumeration_Rep_Expr (Elit)) then
2121 Error_Msg_NE ("missing representation for&!", N, Elit);
2122
2123 else
2124 Val := Enumeration_Rep (Elit);
2125
2126 if Min = No_Uint then
2127 Min := Val;
2128 end if;
2129
2130 if Val /= No_Uint then
2131 if Max /= No_Uint and then Val <= Max then
2132 Error_Msg_NE
2133 ("enumeration value for& not ordered!",
2134 Enumeration_Rep_Expr (Elit), Elit);
2135 end if;
2136
2137 Max := Val;
2138 end if;
2139
2140 -- If there is at least one literal whose representation
2141 -- is not equal to the Pos value, then note that this
2142 -- enumeration type has a non-standard representation.
2143
2144 if Val /= Enumeration_Pos (Elit) then
2145 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
2146 end if;
2147 end if;
2148
2149 Next (Elit);
2150 end loop;
2151
2152 -- Now set proper size information
2153
2154 declare
2155 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
2156
2157 begin
2158 if Has_Size_Clause (Enumtype) then
2159 if Esize (Enumtype) >= Minsize then
2160 null;
2161
2162 else
2163 Minsize :=
2164 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
2165
2166 if Esize (Enumtype) < Minsize then
2167 Error_Msg_N ("previously given size is too small", N);
2168
2169 else
2170 Set_Has_Biased_Representation (Enumtype);
2171 end if;
2172 end if;
2173
2174 else
2175 Set_RM_Size (Enumtype, Minsize);
2176 Set_Enum_Esize (Enumtype);
2177 end if;
2178
2179 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
2180 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
2181 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
2182 end;
2183 end if;
2184
2185 -- We repeat the too late test in case it froze itself!
2186
2187 if Rep_Item_Too_Late (Enumtype, N) then
2188 null;
2189 end if;
2190 end Analyze_Enumeration_Representation_Clause;
2191
2192 ----------------------------
2193 -- Analyze_Free_Statement --
2194 ----------------------------
2195
2196 procedure Analyze_Free_Statement (N : Node_Id) is
2197 begin
2198 Analyze (Expression (N));
2199 end Analyze_Free_Statement;
2200
2201 ---------------------------
2202 -- Analyze_Freeze_Entity --
2203 ---------------------------
2204
2205 procedure Analyze_Freeze_Entity (N : Node_Id) is
2206 E : constant Entity_Id := Entity (N);
2207
2208 begin
2209 -- For tagged types covering interfaces add internal entities that link
2210 -- the primitives of the interfaces with the primitives that cover them.
2211
2212 -- Note: These entities were originally generated only when generating
2213 -- code because their main purpose was to provide support to initialize
2214 -- the secondary dispatch tables. They are now generated also when
2215 -- compiling with no code generation to provide ASIS the relationship
2216 -- between interface primitives and tagged type primitives.
2217
2218 if Ada_Version >= Ada_05
2219 and then Ekind (E) = E_Record_Type
2220 and then Is_Tagged_Type (E)
2221 and then not Is_Interface (E)
2222 and then Has_Interfaces (E)
2223 then
2224 Add_Internal_Interface_Entities (E);
2225 end if;
2226 end Analyze_Freeze_Entity;
2227
2228 ------------------------------------------
2229 -- Analyze_Record_Representation_Clause --
2230 ------------------------------------------
2231
2232 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
2233 Loc : constant Source_Ptr := Sloc (N);
2234 Ident : constant Node_Id := Identifier (N);
2235 Rectype : Entity_Id;
2236 Fent : Entity_Id;
2237 CC : Node_Id;
2238 Posit : Uint;
2239 Fbit : Uint;
2240 Lbit : Uint;
2241 Hbit : Uint := Uint_0;
2242 Comp : Entity_Id;
2243 Ocomp : Entity_Id;
2244 Pcomp : Entity_Id;
2245 Biased : Boolean;
2246
2247 Max_Bit_So_Far : Uint;
2248 -- Records the maximum bit position so far. If all field positions
2249 -- are monotonically increasing, then we can skip the circuit for
2250 -- checking for overlap, since no overlap is possible.
2251
2252 Tagged_Parent : Entity_Id := Empty;
2253 -- This is set in the case of a derived tagged type for which we have
2254 -- Is_Fully_Repped_Tagged_Type True (indicating that all components are
2255 -- positioned by record representation clauses). In this case we must
2256 -- check for overlap between components of this tagged type, and the
2257 -- components of its parent. Tagged_Parent will point to this parent
2258 -- type. For all other cases Tagged_Parent is left set to Empty.
2259
2260 Parent_Last_Bit : Uint;
2261 -- Relevant only if Tagged_Parent is set, Parent_Last_Bit indicates the
2262 -- last bit position for any field in the parent type. We only need to
2263 -- check overlap for fields starting below this point.
2264
2265 Overlap_Check_Required : Boolean;
2266 -- Used to keep track of whether or not an overlap check is required
2267
2268 Ccount : Natural := 0;
2269 -- Number of component clauses in record rep clause
2270
2271 CR_Pragma : Node_Id := Empty;
2272 -- Points to N_Pragma node if Complete_Representation pragma present
2273
2274 begin
2275 if Ignore_Rep_Clauses then
2276 return;
2277 end if;
2278
2279 Find_Type (Ident);
2280 Rectype := Entity (Ident);
2281
2282 if Rectype = Any_Type
2283 or else Rep_Item_Too_Early (Rectype, N)
2284 then
2285 return;
2286 else
2287 Rectype := Underlying_Type (Rectype);
2288 end if;
2289
2290 -- First some basic error checks
2291
2292 if not Is_Record_Type (Rectype) then
2293 Error_Msg_NE
2294 ("record type required, found}", Ident, First_Subtype (Rectype));
2295 return;
2296
2297 elsif Is_Unchecked_Union (Rectype) then
2298 Error_Msg_N
2299 ("record rep clause not allowed for Unchecked_Union", N);
2300
2301 elsif Scope (Rectype) /= Current_Scope then
2302 Error_Msg_N ("type must be declared in this scope", N);
2303 return;
2304
2305 elsif not Is_First_Subtype (Rectype) then
2306 Error_Msg_N ("cannot give record rep clause for subtype", N);
2307 return;
2308
2309 elsif Has_Record_Rep_Clause (Rectype) then
2310 Error_Msg_N ("duplicate record rep clause ignored", N);
2311 return;
2312
2313 elsif Rep_Item_Too_Late (Rectype, N) then
2314 return;
2315 end if;
2316
2317 if Present (Mod_Clause (N)) then
2318 declare
2319 Loc : constant Source_Ptr := Sloc (N);
2320 M : constant Node_Id := Mod_Clause (N);
2321 P : constant List_Id := Pragmas_Before (M);
2322 AtM_Nod : Node_Id;
2323
2324 Mod_Val : Uint;
2325 pragma Warnings (Off, Mod_Val);
2326
2327 begin
2328 Check_Restriction (No_Obsolescent_Features, Mod_Clause (N));
2329
2330 if Warn_On_Obsolescent_Feature then
2331 Error_Msg_N
2332 ("mod clause is an obsolescent feature (RM J.8)?", N);
2333 Error_Msg_N
2334 ("\use alignment attribute definition clause instead?", N);
2335 end if;
2336
2337 if Present (P) then
2338 Analyze_List (P);
2339 end if;
2340
2341 -- In ASIS_Mode mode, expansion is disabled, but we must convert
2342 -- the Mod clause into an alignment clause anyway, so that the
2343 -- back-end can compute and back-annotate properly the size and
2344 -- alignment of types that may include this record.
2345
2346 -- This seems dubious, this destroys the source tree in a manner
2347 -- not detectable by ASIS ???
2348
2349 if Operating_Mode = Check_Semantics
2350 and then ASIS_Mode
2351 then
2352 AtM_Nod :=
2353 Make_Attribute_Definition_Clause (Loc,
2354 Name => New_Reference_To (Base_Type (Rectype), Loc),
2355 Chars => Name_Alignment,
2356 Expression => Relocate_Node (Expression (M)));
2357
2358 Set_From_At_Mod (AtM_Nod);
2359 Insert_After (N, AtM_Nod);
2360 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
2361 Set_Mod_Clause (N, Empty);
2362
2363 else
2364 -- Get the alignment value to perform error checking
2365
2366 Mod_Val := Get_Alignment_Value (Expression (M));
2367
2368 end if;
2369 end;
2370 end if;
2371
2372 -- For untagged types, clear any existing component clauses for the
2373 -- type. If the type is derived, this is what allows us to override
2374 -- a rep clause for the parent. For type extensions, the representation
2375 -- of the inherited components is inherited, so we want to keep previous
2376 -- component clauses for completeness.
2377
2378 if not Is_Tagged_Type (Rectype) then
2379 Comp := First_Component_Or_Discriminant (Rectype);
2380 while Present (Comp) loop
2381 Set_Component_Clause (Comp, Empty);
2382 Next_Component_Or_Discriminant (Comp);
2383 end loop;
2384 end if;
2385
2386 -- See if we have a fully repped derived tagged type
2387
2388 declare
2389 PS : constant Entity_Id := Parent_Subtype (Rectype);
2390
2391 begin
2392 if Present (PS) and then Is_Fully_Repped_Tagged_Type (PS) then
2393 Tagged_Parent := PS;
2394
2395 -- Find maximum bit of any component of the parent type
2396
2397 Parent_Last_Bit := UI_From_Int (System_Address_Size - 1);
2398 Pcomp := First_Entity (Tagged_Parent);
2399 while Present (Pcomp) loop
2400 if Ekind (Pcomp) = E_Discriminant
2401 or else
2402 Ekind (Pcomp) = E_Component
2403 then
2404 if Component_Bit_Offset (Pcomp) /= No_Uint
2405 and then Known_Static_Esize (Pcomp)
2406 then
2407 Parent_Last_Bit :=
2408 UI_Max
2409 (Parent_Last_Bit,
2410 Component_Bit_Offset (Pcomp) + Esize (Pcomp) - 1);
2411 end if;
2412
2413 Next_Entity (Pcomp);
2414 end if;
2415 end loop;
2416 end if;
2417 end;
2418
2419 -- All done if no component clauses
2420
2421 CC := First (Component_Clauses (N));
2422
2423 if No (CC) then
2424 return;
2425 end if;
2426
2427 -- If a tag is present, then create a component clause that places it
2428 -- at the start of the record (otherwise gigi may place it after other
2429 -- fields that have rep clauses).
2430
2431 Fent := First_Entity (Rectype);
2432
2433 if Nkind (Fent) = N_Defining_Identifier
2434 and then Chars (Fent) = Name_uTag
2435 then
2436 Set_Component_Bit_Offset (Fent, Uint_0);
2437 Set_Normalized_Position (Fent, Uint_0);
2438 Set_Normalized_First_Bit (Fent, Uint_0);
2439 Set_Normalized_Position_Max (Fent, Uint_0);
2440 Init_Esize (Fent, System_Address_Size);
2441
2442 Set_Component_Clause (Fent,
2443 Make_Component_Clause (Loc,
2444 Component_Name =>
2445 Make_Identifier (Loc,
2446 Chars => Name_uTag),
2447
2448 Position =>
2449 Make_Integer_Literal (Loc,
2450 Intval => Uint_0),
2451
2452 First_Bit =>
2453 Make_Integer_Literal (Loc,
2454 Intval => Uint_0),
2455
2456 Last_Bit =>
2457 Make_Integer_Literal (Loc,
2458 UI_From_Int (System_Address_Size))));
2459
2460 Ccount := Ccount + 1;
2461 end if;
2462
2463 -- A representation like this applies to the base type
2464
2465 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2466 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2467 Set_Has_Specified_Layout (Base_Type (Rectype));
2468
2469 Max_Bit_So_Far := Uint_Minus_1;
2470 Overlap_Check_Required := False;
2471
2472 -- Process the component clauses
2473
2474 while Present (CC) loop
2475
2476 -- Pragma
2477
2478 if Nkind (CC) = N_Pragma then
2479 Analyze (CC);
2480
2481 -- The only pragma of interest is Complete_Representation
2482
2483 if Pragma_Name (CC) = Name_Complete_Representation then
2484 CR_Pragma := CC;
2485 end if;
2486
2487 -- Processing for real component clause
2488
2489 else
2490 Ccount := Ccount + 1;
2491 Posit := Static_Integer (Position (CC));
2492 Fbit := Static_Integer (First_Bit (CC));
2493 Lbit := Static_Integer (Last_Bit (CC));
2494
2495 if Posit /= No_Uint
2496 and then Fbit /= No_Uint
2497 and then Lbit /= No_Uint
2498 then
2499 if Posit < 0 then
2500 Error_Msg_N
2501 ("position cannot be negative", Position (CC));
2502
2503 elsif Fbit < 0 then
2504 Error_Msg_N
2505 ("first bit cannot be negative", First_Bit (CC));
2506
2507 -- The Last_Bit specified in a component clause must not be
2508 -- less than the First_Bit minus one (RM-13.5.1(10)).
2509
2510 elsif Lbit < Fbit - 1 then
2511 Error_Msg_N
2512 ("last bit cannot be less than first bit minus one",
2513 Last_Bit (CC));
2514
2515 -- Values look OK, so find the corresponding record component
2516 -- Even though the syntax allows an attribute reference for
2517 -- implementation-defined components, GNAT does not allow the
2518 -- tag to get an explicit position.
2519
2520 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2521 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2522 Error_Msg_N ("position of tag cannot be specified", CC);
2523 else
2524 Error_Msg_N ("illegal component name", CC);
2525 end if;
2526
2527 else
2528 Comp := First_Entity (Rectype);
2529 while Present (Comp) loop
2530 exit when Chars (Comp) = Chars (Component_Name (CC));
2531 Next_Entity (Comp);
2532 end loop;
2533
2534 if No (Comp) then
2535
2536 -- Maybe component of base type that is absent from
2537 -- statically constrained first subtype.
2538
2539 Comp := First_Entity (Base_Type (Rectype));
2540 while Present (Comp) loop
2541 exit when Chars (Comp) = Chars (Component_Name (CC));
2542 Next_Entity (Comp);
2543 end loop;
2544 end if;
2545
2546 if No (Comp) then
2547 Error_Msg_N
2548 ("component clause is for non-existent field", CC);
2549
2550 elsif Present (Component_Clause (Comp)) then
2551
2552 -- Diagnose duplicate rep clause, or check consistency
2553 -- if this is an inherited component. In a double fault,
2554 -- there may be a duplicate inconsistent clause for an
2555 -- inherited component.
2556
2557 if Scope (Original_Record_Component (Comp)) = Rectype
2558 or else Parent (Component_Clause (Comp)) = N
2559 then
2560 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2561 Error_Msg_N ("component clause previously given#", CC);
2562
2563 else
2564 declare
2565 Rep1 : constant Node_Id := Component_Clause (Comp);
2566 begin
2567 if Intval (Position (Rep1)) /=
2568 Intval (Position (CC))
2569 or else Intval (First_Bit (Rep1)) /=
2570 Intval (First_Bit (CC))
2571 or else Intval (Last_Bit (Rep1)) /=
2572 Intval (Last_Bit (CC))
2573 then
2574 Error_Msg_N ("component clause inconsistent "
2575 & "with representation of ancestor", CC);
2576 elsif Warn_On_Redundant_Constructs then
2577 Error_Msg_N ("?redundant component clause "
2578 & "for inherited component!", CC);
2579 end if;
2580 end;
2581 end if;
2582
2583 -- Normal case where this is the first component clause we
2584 -- have seen for this entity, so set it up properly.
2585
2586 else
2587 -- Make reference for field in record rep clause and set
2588 -- appropriate entity field in the field identifier.
2589
2590 Generate_Reference
2591 (Comp, Component_Name (CC), Set_Ref => False);
2592 Set_Entity (Component_Name (CC), Comp);
2593
2594 -- Update Fbit and Lbit to the actual bit number
2595
2596 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2597 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2598
2599 if Fbit <= Max_Bit_So_Far then
2600 Overlap_Check_Required := True;
2601 else
2602 Max_Bit_So_Far := Lbit;
2603 end if;
2604
2605 if Has_Size_Clause (Rectype)
2606 and then Esize (Rectype) <= Lbit
2607 then
2608 Error_Msg_N
2609 ("bit number out of range of specified size",
2610 Last_Bit (CC));
2611 else
2612 Set_Component_Clause (Comp, CC);
2613 Set_Component_Bit_Offset (Comp, Fbit);
2614 Set_Esize (Comp, 1 + (Lbit - Fbit));
2615 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2616 Set_Normalized_Position (Comp, Fbit / SSU);
2617
2618 Set_Normalized_Position_Max
2619 (Fent, Normalized_Position (Fent));
2620
2621 if Is_Tagged_Type (Rectype)
2622 and then Fbit < System_Address_Size
2623 then
2624 Error_Msg_NE
2625 ("component overlaps tag field of&",
2626 Component_Name (CC), Rectype);
2627 end if;
2628
2629 -- This information is also set in the corresponding
2630 -- component of the base type, found by accessing the
2631 -- Original_Record_Component link if it is present.
2632
2633 Ocomp := Original_Record_Component (Comp);
2634
2635 if Hbit < Lbit then
2636 Hbit := Lbit;
2637 end if;
2638
2639 Check_Size
2640 (Component_Name (CC),
2641 Etype (Comp),
2642 Esize (Comp),
2643 Biased);
2644
2645 Set_Has_Biased_Representation (Comp, Biased);
2646
2647 if Biased and Warn_On_Biased_Representation then
2648 Error_Msg_F
2649 ("?component clause forces biased "
2650 & "representation", CC);
2651 end if;
2652
2653 if Present (Ocomp) then
2654 Set_Component_Clause (Ocomp, CC);
2655 Set_Component_Bit_Offset (Ocomp, Fbit);
2656 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2657 Set_Normalized_Position (Ocomp, Fbit / SSU);
2658 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2659
2660 Set_Normalized_Position_Max
2661 (Ocomp, Normalized_Position (Ocomp));
2662
2663 Set_Has_Biased_Representation
2664 (Ocomp, Has_Biased_Representation (Comp));
2665 end if;
2666
2667 if Esize (Comp) < 0 then
2668 Error_Msg_N ("component size is negative", CC);
2669 end if;
2670 end if;
2671
2672 -- If OK component size, check parent type overlap if
2673 -- this component might overlap a parent field.
2674
2675 if Present (Tagged_Parent)
2676 and then Fbit <= Parent_Last_Bit
2677 then
2678 Pcomp := First_Entity (Tagged_Parent);
2679 while Present (Pcomp) loop
2680 if (Ekind (Pcomp) = E_Discriminant
2681 or else
2682 Ekind (Pcomp) = E_Component)
2683 and then not Is_Tag (Pcomp)
2684 and then Chars (Pcomp) /= Name_uParent
2685 then
2686 Check_Component_Overlap (Comp, Pcomp);
2687 end if;
2688
2689 Next_Entity (Pcomp);
2690 end loop;
2691 end if;
2692 end if;
2693 end if;
2694 end if;
2695 end if;
2696
2697 Next (CC);
2698 end loop;
2699
2700 -- Now that we have processed all the component clauses, check for
2701 -- overlap. We have to leave this till last, since the components can
2702 -- appear in any arbitrary order in the representation clause.
2703
2704 -- We do not need this check if all specified ranges were monotonic,
2705 -- as recorded by Overlap_Check_Required being False at this stage.
2706
2707 -- This first section checks if there are any overlapping entries at
2708 -- all. It does this by sorting all entries and then seeing if there are
2709 -- any overlaps. If there are none, then that is decisive, but if there
2710 -- are overlaps, they may still be OK (they may result from fields in
2711 -- different variants).
2712
2713 if Overlap_Check_Required then
2714 Overlap_Check1 : declare
2715
2716 OC_Fbit : array (0 .. Ccount) of Uint;
2717 -- First-bit values for component clauses, the value is the offset
2718 -- of the first bit of the field from start of record. The zero
2719 -- entry is for use in sorting.
2720
2721 OC_Lbit : array (0 .. Ccount) of Uint;
2722 -- Last-bit values for component clauses, the value is the offset
2723 -- of the last bit of the field from start of record. The zero
2724 -- entry is for use in sorting.
2725
2726 OC_Count : Natural := 0;
2727 -- Count of entries in OC_Fbit and OC_Lbit
2728
2729 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2730 -- Compare routine for Sort
2731
2732 procedure OC_Move (From : Natural; To : Natural);
2733 -- Move routine for Sort
2734
2735 package Sorting is new GNAT.Heap_Sort_G (OC_Move, OC_Lt);
2736
2737 -----------
2738 -- OC_Lt --
2739 -----------
2740
2741 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2742 begin
2743 return OC_Fbit (Op1) < OC_Fbit (Op2);
2744 end OC_Lt;
2745
2746 -------------
2747 -- OC_Move --
2748 -------------
2749
2750 procedure OC_Move (From : Natural; To : Natural) is
2751 begin
2752 OC_Fbit (To) := OC_Fbit (From);
2753 OC_Lbit (To) := OC_Lbit (From);
2754 end OC_Move;
2755
2756 -- Start of processing for Overlap_Check
2757
2758 begin
2759 CC := First (Component_Clauses (N));
2760 while Present (CC) loop
2761 if Nkind (CC) /= N_Pragma then
2762 Posit := Static_Integer (Position (CC));
2763 Fbit := Static_Integer (First_Bit (CC));
2764 Lbit := Static_Integer (Last_Bit (CC));
2765
2766 if Posit /= No_Uint
2767 and then Fbit /= No_Uint
2768 and then Lbit /= No_Uint
2769 then
2770 OC_Count := OC_Count + 1;
2771 Posit := Posit * SSU;
2772 OC_Fbit (OC_Count) := Fbit + Posit;
2773 OC_Lbit (OC_Count) := Lbit + Posit;
2774 end if;
2775 end if;
2776
2777 Next (CC);
2778 end loop;
2779
2780 Sorting.Sort (OC_Count);
2781
2782 Overlap_Check_Required := False;
2783 for J in 1 .. OC_Count - 1 loop
2784 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2785 Overlap_Check_Required := True;
2786 exit;
2787 end if;
2788 end loop;
2789 end Overlap_Check1;
2790 end if;
2791
2792 -- If Overlap_Check_Required is still True, then we have to do the full
2793 -- scale overlap check, since we have at least two fields that do
2794 -- overlap, and we need to know if that is OK since they are in
2795 -- different variant, or whether we have a definite problem.
2796
2797 if Overlap_Check_Required then
2798 Overlap_Check2 : declare
2799 C1_Ent, C2_Ent : Entity_Id;
2800 -- Entities of components being checked for overlap
2801
2802 Clist : Node_Id;
2803 -- Component_List node whose Component_Items are being checked
2804
2805 Citem : Node_Id;
2806 -- Component declaration for component being checked
2807
2808 begin
2809 C1_Ent := First_Entity (Base_Type (Rectype));
2810
2811 -- Loop through all components in record. For each component check
2812 -- for overlap with any of the preceding elements on the component
2813 -- list containing the component and also, if the component is in
2814 -- a variant, check against components outside the case structure.
2815 -- This latter test is repeated recursively up the variant tree.
2816
2817 Main_Component_Loop : while Present (C1_Ent) loop
2818 if Ekind (C1_Ent) /= E_Component
2819 and then Ekind (C1_Ent) /= E_Discriminant
2820 then
2821 goto Continue_Main_Component_Loop;
2822 end if;
2823
2824 -- Skip overlap check if entity has no declaration node. This
2825 -- happens with discriminants in constrained derived types.
2826 -- Probably we are missing some checks as a result, but that
2827 -- does not seem terribly serious ???
2828
2829 if No (Declaration_Node (C1_Ent)) then
2830 goto Continue_Main_Component_Loop;
2831 end if;
2832
2833 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2834
2835 -- Loop through component lists that need checking. Check the
2836 -- current component list and all lists in variants above us.
2837
2838 Component_List_Loop : loop
2839
2840 -- If derived type definition, go to full declaration
2841 -- If at outer level, check discriminants if there are any.
2842
2843 if Nkind (Clist) = N_Derived_Type_Definition then
2844 Clist := Parent (Clist);
2845 end if;
2846
2847 -- Outer level of record definition, check discriminants
2848
2849 if Nkind_In (Clist, N_Full_Type_Declaration,
2850 N_Private_Type_Declaration)
2851 then
2852 if Has_Discriminants (Defining_Identifier (Clist)) then
2853 C2_Ent :=
2854 First_Discriminant (Defining_Identifier (Clist));
2855 while Present (C2_Ent) loop
2856 exit when C1_Ent = C2_Ent;
2857 Check_Component_Overlap (C1_Ent, C2_Ent);
2858 Next_Discriminant (C2_Ent);
2859 end loop;
2860 end if;
2861
2862 -- Record extension case
2863
2864 elsif Nkind (Clist) = N_Derived_Type_Definition then
2865 Clist := Empty;
2866
2867 -- Otherwise check one component list
2868
2869 else
2870 Citem := First (Component_Items (Clist));
2871
2872 while Present (Citem) loop
2873 if Nkind (Citem) = N_Component_Declaration then
2874 C2_Ent := Defining_Identifier (Citem);
2875 exit when C1_Ent = C2_Ent;
2876 Check_Component_Overlap (C1_Ent, C2_Ent);
2877 end if;
2878
2879 Next (Citem);
2880 end loop;
2881 end if;
2882
2883 -- Check for variants above us (the parent of the Clist can
2884 -- be a variant, in which case its parent is a variant part,
2885 -- and the parent of the variant part is a component list
2886 -- whose components must all be checked against the current
2887 -- component for overlap).
2888
2889 if Nkind (Parent (Clist)) = N_Variant then
2890 Clist := Parent (Parent (Parent (Clist)));
2891
2892 -- Check for possible discriminant part in record, this is
2893 -- treated essentially as another level in the recursion.
2894 -- For this case the parent of the component list is the
2895 -- record definition, and its parent is the full type
2896 -- declaration containing the discriminant specifications.
2897
2898 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2899 Clist := Parent (Parent ((Clist)));
2900
2901 -- If neither of these two cases, we are at the top of
2902 -- the tree.
2903
2904 else
2905 exit Component_List_Loop;
2906 end if;
2907 end loop Component_List_Loop;
2908
2909 <<Continue_Main_Component_Loop>>
2910 Next_Entity (C1_Ent);
2911
2912 end loop Main_Component_Loop;
2913 end Overlap_Check2;
2914 end if;
2915
2916 -- For records that have component clauses for all components, and whose
2917 -- size is less than or equal to 32, we need to know the size in the
2918 -- front end to activate possible packed array processing where the
2919 -- component type is a record.
2920
2921 -- At this stage Hbit + 1 represents the first unused bit from all the
2922 -- component clauses processed, so if the component clauses are
2923 -- complete, then this is the length of the record.
2924
2925 -- For records longer than System.Storage_Unit, and for those where not
2926 -- all components have component clauses, the back end determines the
2927 -- length (it may for example be appropriate to round up the size
2928 -- to some convenient boundary, based on alignment considerations, etc).
2929
2930 if Unknown_RM_Size (Rectype) and then Hbit + 1 <= 32 then
2931
2932 -- Nothing to do if at least one component has no component clause
2933
2934 Comp := First_Component_Or_Discriminant (Rectype);
2935 while Present (Comp) loop
2936 exit when No (Component_Clause (Comp));
2937 Next_Component_Or_Discriminant (Comp);
2938 end loop;
2939
2940 -- If we fall out of loop, all components have component clauses
2941 -- and so we can set the size to the maximum value.
2942
2943 if No (Comp) then
2944 Set_RM_Size (Rectype, Hbit + 1);
2945 end if;
2946 end if;
2947
2948 -- Check missing components if Complete_Representation pragma appeared
2949
2950 if Present (CR_Pragma) then
2951 Comp := First_Component_Or_Discriminant (Rectype);
2952 while Present (Comp) loop
2953 if No (Component_Clause (Comp)) then
2954 Error_Msg_NE
2955 ("missing component clause for &", CR_Pragma, Comp);
2956 end if;
2957
2958 Next_Component_Or_Discriminant (Comp);
2959 end loop;
2960
2961 -- If no Complete_Representation pragma, warn if missing components
2962
2963 elsif Warn_On_Unrepped_Components then
2964 declare
2965 Num_Repped_Components : Nat := 0;
2966 Num_Unrepped_Components : Nat := 0;
2967
2968 begin
2969 -- First count number of repped and unrepped components
2970
2971 Comp := First_Component_Or_Discriminant (Rectype);
2972 while Present (Comp) loop
2973 if Present (Component_Clause (Comp)) then
2974 Num_Repped_Components := Num_Repped_Components + 1;
2975 else
2976 Num_Unrepped_Components := Num_Unrepped_Components + 1;
2977 end if;
2978
2979 Next_Component_Or_Discriminant (Comp);
2980 end loop;
2981
2982 -- We are only interested in the case where there is at least one
2983 -- unrepped component, and at least half the components have rep
2984 -- clauses. We figure that if less than half have them, then the
2985 -- partial rep clause is really intentional. If the component
2986 -- type has no underlying type set at this point (as for a generic
2987 -- formal type), we don't know enough to give a warning on the
2988 -- component.
2989
2990 if Num_Unrepped_Components > 0
2991 and then Num_Unrepped_Components < Num_Repped_Components
2992 then
2993 Comp := First_Component_Or_Discriminant (Rectype);
2994 while Present (Comp) loop
2995 if No (Component_Clause (Comp))
2996 and then Comes_From_Source (Comp)
2997 and then Present (Underlying_Type (Etype (Comp)))
2998 and then (Is_Scalar_Type (Underlying_Type (Etype (Comp)))
2999 or else Size_Known_At_Compile_Time
3000 (Underlying_Type (Etype (Comp))))
3001 and then not Has_Warnings_Off (Rectype)
3002 then
3003 Error_Msg_Sloc := Sloc (Comp);
3004 Error_Msg_NE
3005 ("?no component clause given for & declared #",
3006 N, Comp);
3007 end if;
3008
3009 Next_Component_Or_Discriminant (Comp);
3010 end loop;
3011 end if;
3012 end;
3013 end if;
3014 end Analyze_Record_Representation_Clause;
3015
3016 -----------------------------
3017 -- Check_Component_Overlap --
3018 -----------------------------
3019
3020 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
3021 begin
3022 if Present (Component_Clause (C1_Ent))
3023 and then Present (Component_Clause (C2_Ent))
3024 then
3025 -- Exclude odd case where we have two tag fields in the same record,
3026 -- both at location zero. This seems a bit strange, but it seems to
3027 -- happen in some circumstances ???
3028
3029 if Chars (C1_Ent) = Name_uTag
3030 and then Chars (C2_Ent) = Name_uTag
3031 then
3032 return;
3033 end if;
3034
3035 -- Here we check if the two fields overlap
3036
3037 declare
3038 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
3039 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
3040 E1 : constant Uint := S1 + Esize (C1_Ent);
3041 E2 : constant Uint := S2 + Esize (C2_Ent);
3042
3043 begin
3044 if E2 <= S1 or else E1 <= S2 then
3045 null;
3046 else
3047 Error_Msg_Node_2 :=
3048 Component_Name (Component_Clause (C2_Ent));
3049 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
3050 Error_Msg_Node_1 :=
3051 Component_Name (Component_Clause (C1_Ent));
3052 Error_Msg_N
3053 ("component& overlaps & #",
3054 Component_Name (Component_Clause (C1_Ent)));
3055 end if;
3056 end;
3057 end if;
3058 end Check_Component_Overlap;
3059
3060 -----------------------------------
3061 -- Check_Constant_Address_Clause --
3062 -----------------------------------
3063
3064 procedure Check_Constant_Address_Clause
3065 (Expr : Node_Id;
3066 U_Ent : Entity_Id)
3067 is
3068 procedure Check_At_Constant_Address (Nod : Node_Id);
3069 -- Checks that the given node N represents a name whose 'Address is
3070 -- constant (in the same sense as OK_Constant_Address_Clause, i.e. the
3071 -- address value is the same at the point of declaration of U_Ent and at
3072 -- the time of elaboration of the address clause.
3073
3074 procedure Check_Expr_Constants (Nod : Node_Id);
3075 -- Checks that Nod meets the requirements for a constant address clause
3076 -- in the sense of the enclosing procedure.
3077
3078 procedure Check_List_Constants (Lst : List_Id);
3079 -- Check that all elements of list Lst meet the requirements for a
3080 -- constant address clause in the sense of the enclosing procedure.
3081
3082 -------------------------------
3083 -- Check_At_Constant_Address --
3084 -------------------------------
3085
3086 procedure Check_At_Constant_Address (Nod : Node_Id) is
3087 begin
3088 if Is_Entity_Name (Nod) then
3089 if Present (Address_Clause (Entity ((Nod)))) then
3090 Error_Msg_NE
3091 ("invalid address clause for initialized object &!",
3092 Nod, U_Ent);
3093 Error_Msg_NE
3094 ("address for& cannot" &
3095 " depend on another address clause! (RM 13.1(22))!",
3096 Nod, U_Ent);
3097
3098 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
3099 and then Sloc (U_Ent) < Sloc (Entity (Nod))
3100 then
3101 Error_Msg_NE
3102 ("invalid address clause for initialized object &!",
3103 Nod, U_Ent);
3104 Error_Msg_Node_2 := U_Ent;
3105 Error_Msg_NE
3106 ("\& must be defined before & (RM 13.1(22))!",
3107 Nod, Entity (Nod));
3108 end if;
3109
3110 elsif Nkind (Nod) = N_Selected_Component then
3111 declare
3112 T : constant Entity_Id := Etype (Prefix (Nod));
3113
3114 begin
3115 if (Is_Record_Type (T)
3116 and then Has_Discriminants (T))
3117 or else
3118 (Is_Access_Type (T)
3119 and then Is_Record_Type (Designated_Type (T))
3120 and then Has_Discriminants (Designated_Type (T)))
3121 then
3122 Error_Msg_NE
3123 ("invalid address clause for initialized object &!",
3124 Nod, U_Ent);
3125 Error_Msg_N
3126 ("\address cannot depend on component" &
3127 " of discriminated record (RM 13.1(22))!",
3128 Nod);
3129 else
3130 Check_At_Constant_Address (Prefix (Nod));
3131 end if;
3132 end;
3133
3134 elsif Nkind (Nod) = N_Indexed_Component then
3135 Check_At_Constant_Address (Prefix (Nod));
3136 Check_List_Constants (Expressions (Nod));
3137
3138 else
3139 Check_Expr_Constants (Nod);
3140 end if;
3141 end Check_At_Constant_Address;
3142
3143 --------------------------
3144 -- Check_Expr_Constants --
3145 --------------------------
3146
3147 procedure Check_Expr_Constants (Nod : Node_Id) is
3148 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
3149 Ent : Entity_Id := Empty;
3150
3151 begin
3152 if Nkind (Nod) in N_Has_Etype
3153 and then Etype (Nod) = Any_Type
3154 then
3155 return;
3156 end if;
3157
3158 case Nkind (Nod) is
3159 when N_Empty | N_Error =>
3160 return;
3161
3162 when N_Identifier | N_Expanded_Name =>
3163 Ent := Entity (Nod);
3164
3165 -- We need to look at the original node if it is different
3166 -- from the node, since we may have rewritten things and
3167 -- substituted an identifier representing the rewrite.
3168
3169 if Original_Node (Nod) /= Nod then
3170 Check_Expr_Constants (Original_Node (Nod));
3171
3172 -- If the node is an object declaration without initial
3173 -- value, some code has been expanded, and the expression
3174 -- is not constant, even if the constituents might be
3175 -- acceptable, as in A'Address + offset.
3176
3177 if Ekind (Ent) = E_Variable
3178 and then
3179 Nkind (Declaration_Node (Ent)) = N_Object_Declaration
3180 and then
3181 No (Expression (Declaration_Node (Ent)))
3182 then
3183 Error_Msg_NE
3184 ("invalid address clause for initialized object &!",
3185 Nod, U_Ent);
3186
3187 -- If entity is constant, it may be the result of expanding
3188 -- a check. We must verify that its declaration appears
3189 -- before the object in question, else we also reject the
3190 -- address clause.
3191
3192 elsif Ekind (Ent) = E_Constant
3193 and then In_Same_Source_Unit (Ent, U_Ent)
3194 and then Sloc (Ent) > Loc_U_Ent
3195 then
3196 Error_Msg_NE
3197 ("invalid address clause for initialized object &!",
3198 Nod, U_Ent);
3199 end if;
3200
3201 return;
3202 end if;
3203
3204 -- Otherwise look at the identifier and see if it is OK
3205
3206 if Ekind (Ent) = E_Named_Integer
3207 or else
3208 Ekind (Ent) = E_Named_Real
3209 or else
3210 Is_Type (Ent)
3211 then
3212 return;
3213
3214 elsif
3215 Ekind (Ent) = E_Constant
3216 or else
3217 Ekind (Ent) = E_In_Parameter
3218 then
3219 -- This is the case where we must have Ent defined before
3220 -- U_Ent. Clearly if they are in different units this
3221 -- requirement is met since the unit containing Ent is
3222 -- already processed.
3223
3224 if not In_Same_Source_Unit (Ent, U_Ent) then
3225 return;
3226
3227 -- Otherwise location of Ent must be before the location
3228 -- of U_Ent, that's what prior defined means.
3229
3230 elsif Sloc (Ent) < Loc_U_Ent then
3231 return;
3232
3233 else
3234 Error_Msg_NE
3235 ("invalid address clause for initialized object &!",
3236 Nod, U_Ent);
3237 Error_Msg_Node_2 := U_Ent;
3238 Error_Msg_NE
3239 ("\& must be defined before & (RM 13.1(22))!",
3240 Nod, Ent);
3241 end if;
3242
3243 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
3244 Check_Expr_Constants (Original_Node (Nod));
3245
3246 else
3247 Error_Msg_NE
3248 ("invalid address clause for initialized object &!",
3249 Nod, U_Ent);
3250
3251 if Comes_From_Source (Ent) then
3252 Error_Msg_NE
3253 ("\reference to variable& not allowed"
3254 & " (RM 13.1(22))!", Nod, Ent);
3255 else
3256 Error_Msg_N
3257 ("non-static expression not allowed"
3258 & " (RM 13.1(22))!", Nod);
3259 end if;
3260 end if;
3261
3262 when N_Integer_Literal =>
3263
3264 -- If this is a rewritten unchecked conversion, in a system
3265 -- where Address is an integer type, always use the base type
3266 -- for a literal value. This is user-friendly and prevents
3267 -- order-of-elaboration issues with instances of unchecked
3268 -- conversion.
3269
3270 if Nkind (Original_Node (Nod)) = N_Function_Call then
3271 Set_Etype (Nod, Base_Type (Etype (Nod)));
3272 end if;
3273
3274 when N_Real_Literal |
3275 N_String_Literal |
3276 N_Character_Literal =>
3277 return;
3278
3279 when N_Range =>
3280 Check_Expr_Constants (Low_Bound (Nod));
3281 Check_Expr_Constants (High_Bound (Nod));
3282
3283 when N_Explicit_Dereference =>
3284 Check_Expr_Constants (Prefix (Nod));
3285
3286 when N_Indexed_Component =>
3287 Check_Expr_Constants (Prefix (Nod));
3288 Check_List_Constants (Expressions (Nod));
3289
3290 when N_Slice =>
3291 Check_Expr_Constants (Prefix (Nod));
3292 Check_Expr_Constants (Discrete_Range (Nod));
3293
3294 when N_Selected_Component =>
3295 Check_Expr_Constants (Prefix (Nod));
3296
3297 when N_Attribute_Reference =>
3298 if Attribute_Name (Nod) = Name_Address
3299 or else
3300 Attribute_Name (Nod) = Name_Access
3301 or else
3302 Attribute_Name (Nod) = Name_Unchecked_Access
3303 or else
3304 Attribute_Name (Nod) = Name_Unrestricted_Access
3305 then
3306 Check_At_Constant_Address (Prefix (Nod));
3307
3308 else
3309 Check_Expr_Constants (Prefix (Nod));
3310 Check_List_Constants (Expressions (Nod));
3311 end if;
3312
3313 when N_Aggregate =>
3314 Check_List_Constants (Component_Associations (Nod));
3315 Check_List_Constants (Expressions (Nod));
3316
3317 when N_Component_Association =>
3318 Check_Expr_Constants (Expression (Nod));
3319
3320 when N_Extension_Aggregate =>
3321 Check_Expr_Constants (Ancestor_Part (Nod));
3322 Check_List_Constants (Component_Associations (Nod));
3323 Check_List_Constants (Expressions (Nod));
3324
3325 when N_Null =>
3326 return;
3327
3328 when N_Binary_Op | N_Short_Circuit | N_Membership_Test =>
3329 Check_Expr_Constants (Left_Opnd (Nod));
3330 Check_Expr_Constants (Right_Opnd (Nod));
3331
3332 when N_Unary_Op =>
3333 Check_Expr_Constants (Right_Opnd (Nod));
3334
3335 when N_Type_Conversion |
3336 N_Qualified_Expression |
3337 N_Allocator =>
3338 Check_Expr_Constants (Expression (Nod));
3339
3340 when N_Unchecked_Type_Conversion =>
3341 Check_Expr_Constants (Expression (Nod));
3342
3343 -- If this is a rewritten unchecked conversion, subtypes in
3344 -- this node are those created within the instance. To avoid
3345 -- order of elaboration issues, replace them with their base
3346 -- types. Note that address clauses can cause order of
3347 -- elaboration problems because they are elaborated by the
3348 -- back-end at the point of definition, and may mention
3349 -- entities declared in between (as long as everything is
3350 -- static). It is user-friendly to allow unchecked conversions
3351 -- in this context.
3352
3353 if Nkind (Original_Node (Nod)) = N_Function_Call then
3354 Set_Etype (Expression (Nod),
3355 Base_Type (Etype (Expression (Nod))));
3356 Set_Etype (Nod, Base_Type (Etype (Nod)));
3357 end if;
3358
3359 when N_Function_Call =>
3360 if not Is_Pure (Entity (Name (Nod))) then
3361 Error_Msg_NE
3362 ("invalid address clause for initialized object &!",
3363 Nod, U_Ent);
3364
3365 Error_Msg_NE
3366 ("\function & is not pure (RM 13.1(22))!",
3367 Nod, Entity (Name (Nod)));
3368
3369 else
3370 Check_List_Constants (Parameter_Associations (Nod));
3371 end if;
3372
3373 when N_Parameter_Association =>
3374 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
3375
3376 when others =>
3377 Error_Msg_NE
3378 ("invalid address clause for initialized object &!",
3379 Nod, U_Ent);
3380 Error_Msg_NE
3381 ("\must be constant defined before& (RM 13.1(22))!",
3382 Nod, U_Ent);
3383 end case;
3384 end Check_Expr_Constants;
3385
3386 --------------------------
3387 -- Check_List_Constants --
3388 --------------------------
3389
3390 procedure Check_List_Constants (Lst : List_Id) is
3391 Nod1 : Node_Id;
3392
3393 begin
3394 if Present (Lst) then
3395 Nod1 := First (Lst);
3396 while Present (Nod1) loop
3397 Check_Expr_Constants (Nod1);
3398 Next (Nod1);
3399 end loop;
3400 end if;
3401 end Check_List_Constants;
3402
3403 -- Start of processing for Check_Constant_Address_Clause
3404
3405 begin
3406 Check_Expr_Constants (Expr);
3407 end Check_Constant_Address_Clause;
3408
3409 ----------------
3410 -- Check_Size --
3411 ----------------
3412
3413 procedure Check_Size
3414 (N : Node_Id;
3415 T : Entity_Id;
3416 Siz : Uint;
3417 Biased : out Boolean)
3418 is
3419 UT : constant Entity_Id := Underlying_Type (T);
3420 M : Uint;
3421
3422 begin
3423 Biased := False;
3424
3425 -- Dismiss cases for generic types or types with previous errors
3426
3427 if No (UT)
3428 or else UT = Any_Type
3429 or else Is_Generic_Type (UT)
3430 or else Is_Generic_Type (Root_Type (UT))
3431 then
3432 return;
3433
3434 -- Check case of bit packed array
3435
3436 elsif Is_Array_Type (UT)
3437 and then Known_Static_Component_Size (UT)
3438 and then Is_Bit_Packed_Array (UT)
3439 then
3440 declare
3441 Asiz : Uint;
3442 Indx : Node_Id;
3443 Ityp : Entity_Id;
3444
3445 begin
3446 Asiz := Component_Size (UT);
3447 Indx := First_Index (UT);
3448 loop
3449 Ityp := Etype (Indx);
3450
3451 -- If non-static bound, then we are not in the business of
3452 -- trying to check the length, and indeed an error will be
3453 -- issued elsewhere, since sizes of non-static array types
3454 -- cannot be set implicitly or explicitly.
3455
3456 if not Is_Static_Subtype (Ityp) then
3457 return;
3458 end if;
3459
3460 -- Otherwise accumulate next dimension
3461
3462 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
3463 Expr_Value (Type_Low_Bound (Ityp)) +
3464 Uint_1);
3465
3466 Next_Index (Indx);
3467 exit when No (Indx);
3468 end loop;
3469
3470 if Asiz <= Siz then
3471 return;
3472 else
3473 Error_Msg_Uint_1 := Asiz;
3474 Error_Msg_NE
3475 ("size for& too small, minimum allowed is ^", N, T);
3476 Set_Esize (T, Asiz);
3477 Set_RM_Size (T, Asiz);
3478 end if;
3479 end;
3480
3481 -- All other composite types are ignored
3482
3483 elsif Is_Composite_Type (UT) then
3484 return;
3485
3486 -- For fixed-point types, don't check minimum if type is not frozen,
3487 -- since we don't know all the characteristics of the type that can
3488 -- affect the size (e.g. a specified small) till freeze time.
3489
3490 elsif Is_Fixed_Point_Type (UT)
3491 and then not Is_Frozen (UT)
3492 then
3493 null;
3494
3495 -- Cases for which a minimum check is required
3496
3497 else
3498 -- Ignore if specified size is correct for the type
3499
3500 if Known_Esize (UT) and then Siz = Esize (UT) then
3501 return;
3502 end if;
3503
3504 -- Otherwise get minimum size
3505
3506 M := UI_From_Int (Minimum_Size (UT));
3507
3508 if Siz < M then
3509
3510 -- Size is less than minimum size, but one possibility remains
3511 -- that we can manage with the new size if we bias the type.
3512
3513 M := UI_From_Int (Minimum_Size (UT, Biased => True));
3514
3515 if Siz < M then
3516 Error_Msg_Uint_1 := M;
3517 Error_Msg_NE
3518 ("size for& too small, minimum allowed is ^", N, T);
3519 Set_Esize (T, M);
3520 Set_RM_Size (T, M);
3521 else
3522 Biased := True;
3523 end if;
3524 end if;
3525 end if;
3526 end Check_Size;
3527
3528 -------------------------
3529 -- Get_Alignment_Value --
3530 -------------------------
3531
3532 function Get_Alignment_Value (Expr : Node_Id) return Uint is
3533 Align : constant Uint := Static_Integer (Expr);
3534
3535 begin
3536 if Align = No_Uint then
3537 return No_Uint;
3538
3539 elsif Align <= 0 then
3540 Error_Msg_N ("alignment value must be positive", Expr);
3541 return No_Uint;
3542
3543 else
3544 for J in Int range 0 .. 64 loop
3545 declare
3546 M : constant Uint := Uint_2 ** J;
3547
3548 begin
3549 exit when M = Align;
3550
3551 if M > Align then
3552 Error_Msg_N
3553 ("alignment value must be power of 2", Expr);
3554 return No_Uint;
3555 end if;
3556 end;
3557 end loop;
3558
3559 return Align;
3560 end if;
3561 end Get_Alignment_Value;
3562
3563 ----------------
3564 -- Initialize --
3565 ----------------
3566
3567 procedure Initialize is
3568 begin
3569 Unchecked_Conversions.Init;
3570 end Initialize;
3571
3572 -------------------------
3573 -- Is_Operational_Item --
3574 -------------------------
3575
3576 function Is_Operational_Item (N : Node_Id) return Boolean is
3577 begin
3578 if Nkind (N) /= N_Attribute_Definition_Clause then
3579 return False;
3580 else
3581 declare
3582 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3583 begin
3584 return Id = Attribute_Input
3585 or else Id = Attribute_Output
3586 or else Id = Attribute_Read
3587 or else Id = Attribute_Write
3588 or else Id = Attribute_External_Tag;
3589 end;
3590 end if;
3591 end Is_Operational_Item;
3592
3593 ------------------
3594 -- Minimum_Size --
3595 ------------------
3596
3597 function Minimum_Size
3598 (T : Entity_Id;
3599 Biased : Boolean := False) return Nat
3600 is
3601 Lo : Uint := No_Uint;
3602 Hi : Uint := No_Uint;
3603 LoR : Ureal := No_Ureal;
3604 HiR : Ureal := No_Ureal;
3605 LoSet : Boolean := False;
3606 HiSet : Boolean := False;
3607 B : Uint;
3608 S : Nat;
3609 Ancest : Entity_Id;
3610 R_Typ : constant Entity_Id := Root_Type (T);
3611
3612 begin
3613 -- If bad type, return 0
3614
3615 if T = Any_Type then
3616 return 0;
3617
3618 -- For generic types, just return zero. There cannot be any legitimate
3619 -- need to know such a size, but this routine may be called with a
3620 -- generic type as part of normal processing.
3621
3622 elsif Is_Generic_Type (R_Typ)
3623 or else R_Typ = Any_Type
3624 then
3625 return 0;
3626
3627 -- Access types. Normally an access type cannot have a size smaller
3628 -- than the size of System.Address. The exception is on VMS, where
3629 -- we have short and long addresses, and it is possible for an access
3630 -- type to have a short address size (and thus be less than the size
3631 -- of System.Address itself). We simply skip the check for VMS, and
3632 -- leave it to the back end to do the check.
3633
3634 elsif Is_Access_Type (T) then
3635 if OpenVMS_On_Target then
3636 return 0;
3637 else
3638 return System_Address_Size;
3639 end if;
3640
3641 -- Floating-point types
3642
3643 elsif Is_Floating_Point_Type (T) then
3644 return UI_To_Int (Esize (R_Typ));
3645
3646 -- Discrete types
3647
3648 elsif Is_Discrete_Type (T) then
3649
3650 -- The following loop is looking for the nearest compile time known
3651 -- bounds following the ancestor subtype chain. The idea is to find
3652 -- the most restrictive known bounds information.
3653
3654 Ancest := T;
3655 loop
3656 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3657 return 0;
3658 end if;
3659
3660 if not LoSet then
3661 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3662 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3663 LoSet := True;
3664 exit when HiSet;
3665 end if;
3666 end if;
3667
3668 if not HiSet then
3669 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3670 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3671 HiSet := True;
3672 exit when LoSet;
3673 end if;
3674 end if;
3675
3676 Ancest := Ancestor_Subtype (Ancest);
3677
3678 if No (Ancest) then
3679 Ancest := Base_Type (T);
3680
3681 if Is_Generic_Type (Ancest) then
3682 return 0;
3683 end if;
3684 end if;
3685 end loop;
3686
3687 -- Fixed-point types. We can't simply use Expr_Value to get the
3688 -- Corresponding_Integer_Value values of the bounds, since these do not
3689 -- get set till the type is frozen, and this routine can be called
3690 -- before the type is frozen. Similarly the test for bounds being static
3691 -- needs to include the case where we have unanalyzed real literals for
3692 -- the same reason.
3693
3694 elsif Is_Fixed_Point_Type (T) then
3695
3696 -- The following loop is looking for the nearest compile time known
3697 -- bounds following the ancestor subtype chain. The idea is to find
3698 -- the most restrictive known bounds information.
3699
3700 Ancest := T;
3701 loop
3702 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3703 return 0;
3704 end if;
3705
3706 -- Note: In the following two tests for LoSet and HiSet, it may
3707 -- seem redundant to test for N_Real_Literal here since normally
3708 -- one would assume that the test for the value being known at
3709 -- compile time includes this case. However, there is a glitch.
3710 -- If the real literal comes from folding a non-static expression,
3711 -- then we don't consider any non- static expression to be known
3712 -- at compile time if we are in configurable run time mode (needed
3713 -- in some cases to give a clearer definition of what is and what
3714 -- is not accepted). So the test is indeed needed. Without it, we
3715 -- would set neither Lo_Set nor Hi_Set and get an infinite loop.
3716
3717 if not LoSet then
3718 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3719 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3720 then
3721 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3722 LoSet := True;
3723 exit when HiSet;
3724 end if;
3725 end if;
3726
3727 if not HiSet then
3728 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3729 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3730 then
3731 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3732 HiSet := True;
3733 exit when LoSet;
3734 end if;
3735 end if;
3736
3737 Ancest := Ancestor_Subtype (Ancest);
3738
3739 if No (Ancest) then
3740 Ancest := Base_Type (T);
3741
3742 if Is_Generic_Type (Ancest) then
3743 return 0;
3744 end if;
3745 end if;
3746 end loop;
3747
3748 Lo := UR_To_Uint (LoR / Small_Value (T));
3749 Hi := UR_To_Uint (HiR / Small_Value (T));
3750
3751 -- No other types allowed
3752
3753 else
3754 raise Program_Error;
3755 end if;
3756
3757 -- Fall through with Hi and Lo set. Deal with biased case
3758
3759 if (Biased
3760 and then not Is_Fixed_Point_Type (T)
3761 and then not (Is_Enumeration_Type (T)
3762 and then Has_Non_Standard_Rep (T)))
3763 or else Has_Biased_Representation (T)
3764 then
3765 Hi := Hi - Lo;
3766 Lo := Uint_0;
3767 end if;
3768
3769 -- Signed case. Note that we consider types like range 1 .. -1 to be
3770 -- signed for the purpose of computing the size, since the bounds have
3771 -- to be accommodated in the base type.
3772
3773 if Lo < 0 or else Hi < 0 then
3774 S := 1;
3775 B := Uint_1;
3776
3777 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3778 -- Note that we accommodate the case where the bounds cross. This
3779 -- can happen either because of the way the bounds are declared
3780 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3781
3782 while Lo < -B
3783 or else Hi < -B
3784 or else Lo >= B
3785 or else Hi >= B
3786 loop
3787 B := Uint_2 ** S;
3788 S := S + 1;
3789 end loop;
3790
3791 -- Unsigned case
3792
3793 else
3794 -- If both bounds are positive, make sure that both are represen-
3795 -- table in the case where the bounds are crossed. This can happen
3796 -- either because of the way the bounds are declared, or because of
3797 -- the algorithm in Freeze_Fixed_Point_Type.
3798
3799 if Lo > Hi then
3800 Hi := Lo;
3801 end if;
3802
3803 -- S = size, (can accommodate 0 .. (2**size - 1))
3804
3805 S := 0;
3806 while Hi >= Uint_2 ** S loop
3807 S := S + 1;
3808 end loop;
3809 end if;
3810
3811 return S;
3812 end Minimum_Size;
3813
3814 ---------------------------
3815 -- New_Stream_Subprogram --
3816 ---------------------------
3817
3818 procedure New_Stream_Subprogram
3819 (N : Node_Id;
3820 Ent : Entity_Id;
3821 Subp : Entity_Id;
3822 Nam : TSS_Name_Type)
3823 is
3824 Loc : constant Source_Ptr := Sloc (N);
3825 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3826 Subp_Id : Entity_Id;
3827 Subp_Decl : Node_Id;
3828 F : Entity_Id;
3829 Etyp : Entity_Id;
3830
3831 Defer_Declaration : constant Boolean :=
3832 Is_Tagged_Type (Ent) or else Is_Private_Type (Ent);
3833 -- For a tagged type, there is a declaration for each stream attribute
3834 -- at the freeze point, and we must generate only a completion of this
3835 -- declaration. We do the same for private types, because the full view
3836 -- might be tagged. Otherwise we generate a declaration at the point of
3837 -- the attribute definition clause.
3838
3839 function Build_Spec return Node_Id;
3840 -- Used for declaration and renaming declaration, so that this is
3841 -- treated as a renaming_as_body.
3842
3843 ----------------
3844 -- Build_Spec --
3845 ----------------
3846
3847 function Build_Spec return Node_Id is
3848 Out_P : constant Boolean := (Nam = TSS_Stream_Read);
3849 Formals : List_Id;
3850 Spec : Node_Id;
3851 T_Ref : constant Node_Id := New_Reference_To (Etyp, Loc);
3852
3853 begin
3854 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3855
3856 -- S : access Root_Stream_Type'Class
3857
3858 Formals := New_List (
3859 Make_Parameter_Specification (Loc,
3860 Defining_Identifier =>
3861 Make_Defining_Identifier (Loc, Name_S),
3862 Parameter_Type =>
3863 Make_Access_Definition (Loc,
3864 Subtype_Mark =>
3865 New_Reference_To (
3866 Designated_Type (Etype (F)), Loc))));
3867
3868 if Nam = TSS_Stream_Input then
3869 Spec := Make_Function_Specification (Loc,
3870 Defining_Unit_Name => Subp_Id,
3871 Parameter_Specifications => Formals,
3872 Result_Definition => T_Ref);
3873 else
3874 -- V : [out] T
3875
3876 Append_To (Formals,
3877 Make_Parameter_Specification (Loc,
3878 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
3879 Out_Present => Out_P,
3880 Parameter_Type => T_Ref));
3881
3882 Spec := Make_Procedure_Specification (Loc,
3883 Defining_Unit_Name => Subp_Id,
3884 Parameter_Specifications => Formals);
3885 end if;
3886
3887 return Spec;
3888 end Build_Spec;
3889
3890 -- Start of processing for New_Stream_Subprogram
3891
3892 begin
3893 F := First_Formal (Subp);
3894
3895 if Ekind (Subp) = E_Procedure then
3896 Etyp := Etype (Next_Formal (F));
3897 else
3898 Etyp := Etype (Subp);
3899 end if;
3900
3901 -- Prepare subprogram declaration and insert it as an action on the
3902 -- clause node. The visibility for this entity is used to test for
3903 -- visibility of the attribute definition clause (in the sense of
3904 -- 8.3(23) as amended by AI-195).
3905
3906 if not Defer_Declaration then
3907 Subp_Decl :=
3908 Make_Subprogram_Declaration (Loc,
3909 Specification => Build_Spec);
3910
3911 -- For a tagged type, there is always a visible declaration for each
3912 -- stream TSS (it is a predefined primitive operation), and the
3913 -- completion of this declaration occurs at the freeze point, which is
3914 -- not always visible at places where the attribute definition clause is
3915 -- visible. So, we create a dummy entity here for the purpose of
3916 -- tracking the visibility of the attribute definition clause itself.
3917
3918 else
3919 Subp_Id :=
3920 Make_Defining_Identifier (Loc,
3921 Chars => New_External_Name (Sname, 'V'));
3922 Subp_Decl :=
3923 Make_Object_Declaration (Loc,
3924 Defining_Identifier => Subp_Id,
3925 Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc));
3926 end if;
3927
3928 Insert_Action (N, Subp_Decl);
3929 Set_Entity (N, Subp_Id);
3930
3931 Subp_Decl :=
3932 Make_Subprogram_Renaming_Declaration (Loc,
3933 Specification => Build_Spec,
3934 Name => New_Reference_To (Subp, Loc));
3935
3936 if Defer_Declaration then
3937 Set_TSS (Base_Type (Ent), Subp_Id);
3938 else
3939 Insert_Action (N, Subp_Decl);
3940 Copy_TSS (Subp_Id, Base_Type (Ent));
3941 end if;
3942 end New_Stream_Subprogram;
3943
3944 ------------------------
3945 -- Rep_Item_Too_Early --
3946 ------------------------
3947
3948 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3949 begin
3950 -- Cannot apply non-operational rep items to generic types
3951
3952 if Is_Operational_Item (N) then
3953 return False;
3954
3955 elsif Is_Type (T)
3956 and then Is_Generic_Type (Root_Type (T))
3957 then
3958 Error_Msg_N
3959 ("representation item not allowed for generic type", N);
3960 return True;
3961 end if;
3962
3963 -- Otherwise check for incomplete type
3964
3965 if Is_Incomplete_Or_Private_Type (T)
3966 and then No (Underlying_Type (T))
3967 then
3968 Error_Msg_N
3969 ("representation item must be after full type declaration", N);
3970 return True;
3971
3972 -- If the type has incomplete components, a representation clause is
3973 -- illegal but stream attributes and Convention pragmas are correct.
3974
3975 elsif Has_Private_Component (T) then
3976 if Nkind (N) = N_Pragma then
3977 return False;
3978 else
3979 Error_Msg_N
3980 ("representation item must appear after type is fully defined",
3981 N);
3982 return True;
3983 end if;
3984 else
3985 return False;
3986 end if;
3987 end Rep_Item_Too_Early;
3988
3989 -----------------------
3990 -- Rep_Item_Too_Late --
3991 -----------------------
3992
3993 function Rep_Item_Too_Late
3994 (T : Entity_Id;
3995 N : Node_Id;
3996 FOnly : Boolean := False) return Boolean
3997 is
3998 S : Entity_Id;
3999 Parent_Type : Entity_Id;
4000
4001 procedure Too_Late;
4002 -- Output the too late message. Note that this is not considered a
4003 -- serious error, since the effect is simply that we ignore the
4004 -- representation clause in this case.
4005
4006 --------------
4007 -- Too_Late --
4008 --------------
4009
4010 procedure Too_Late is
4011 begin
4012 Error_Msg_N ("|representation item appears too late!", N);
4013 end Too_Late;
4014
4015 -- Start of processing for Rep_Item_Too_Late
4016
4017 begin
4018 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
4019 -- types, which may be frozen if they appear in a representation clause
4020 -- for a local type.
4021
4022 if Is_Frozen (T)
4023 and then not From_With_Type (T)
4024 then
4025 Too_Late;
4026 S := First_Subtype (T);
4027
4028 if Present (Freeze_Node (S)) then
4029 Error_Msg_NE
4030 ("?no more representation items for }", Freeze_Node (S), S);
4031 end if;
4032
4033 return True;
4034
4035 -- Check for case of non-tagged derived type whose parent either has
4036 -- primitive operations, or is a by reference type (RM 13.1(10)).
4037
4038 elsif Is_Type (T)
4039 and then not FOnly
4040 and then Is_Derived_Type (T)
4041 and then not Is_Tagged_Type (T)
4042 then
4043 Parent_Type := Etype (Base_Type (T));
4044
4045 if Has_Primitive_Operations (Parent_Type) then
4046 Too_Late;
4047 Error_Msg_NE
4048 ("primitive operations already defined for&!", N, Parent_Type);
4049 return True;
4050
4051 elsif Is_By_Reference_Type (Parent_Type) then
4052 Too_Late;
4053 Error_Msg_NE
4054 ("parent type & is a by reference type!", N, Parent_Type);
4055 return True;
4056 end if;
4057 end if;
4058
4059 -- No error, link item into head of chain of rep items for the entity,
4060 -- but avoid chaining if we have an overloadable entity, and the pragma
4061 -- is one that can apply to multiple overloaded entities.
4062
4063 if Is_Overloadable (T)
4064 and then Nkind (N) = N_Pragma
4065 then
4066 declare
4067 Pname : constant Name_Id := Pragma_Name (N);
4068 begin
4069 if Pname = Name_Convention or else
4070 Pname = Name_Import or else
4071 Pname = Name_Export or else
4072 Pname = Name_External or else
4073 Pname = Name_Interface
4074 then
4075 return False;
4076 end if;
4077 end;
4078 end if;
4079
4080 Record_Rep_Item (T, N);
4081 return False;
4082 end Rep_Item_Too_Late;
4083
4084 -------------------------
4085 -- Same_Representation --
4086 -------------------------
4087
4088 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
4089 T1 : constant Entity_Id := Underlying_Type (Typ1);
4090 T2 : constant Entity_Id := Underlying_Type (Typ2);
4091
4092 begin
4093 -- A quick check, if base types are the same, then we definitely have
4094 -- the same representation, because the subtype specific representation
4095 -- attributes (Size and Alignment) do not affect representation from
4096 -- the point of view of this test.
4097
4098 if Base_Type (T1) = Base_Type (T2) then
4099 return True;
4100
4101 elsif Is_Private_Type (Base_Type (T2))
4102 and then Base_Type (T1) = Full_View (Base_Type (T2))
4103 then
4104 return True;
4105 end if;
4106
4107 -- Tagged types never have differing representations
4108
4109 if Is_Tagged_Type (T1) then
4110 return True;
4111 end if;
4112
4113 -- Representations are definitely different if conventions differ
4114
4115 if Convention (T1) /= Convention (T2) then
4116 return False;
4117 end if;
4118
4119 -- Representations are different if component alignments differ
4120
4121 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
4122 and then
4123 (Is_Record_Type (T2) or else Is_Array_Type (T2))
4124 and then Component_Alignment (T1) /= Component_Alignment (T2)
4125 then
4126 return False;
4127 end if;
4128
4129 -- For arrays, the only real issue is component size. If we know the
4130 -- component size for both arrays, and it is the same, then that's
4131 -- good enough to know we don't have a change of representation.
4132
4133 if Is_Array_Type (T1) then
4134 if Known_Component_Size (T1)
4135 and then Known_Component_Size (T2)
4136 and then Component_Size (T1) = Component_Size (T2)
4137 then
4138 return True;
4139 end if;
4140 end if;
4141
4142 -- Types definitely have same representation if neither has non-standard
4143 -- representation since default representations are always consistent.
4144 -- If only one has non-standard representation, and the other does not,
4145 -- then we consider that they do not have the same representation. They
4146 -- might, but there is no way of telling early enough.
4147
4148 if Has_Non_Standard_Rep (T1) then
4149 if not Has_Non_Standard_Rep (T2) then
4150 return False;
4151 end if;
4152 else
4153 return not Has_Non_Standard_Rep (T2);
4154 end if;
4155
4156 -- Here the two types both have non-standard representation, and we need
4157 -- to determine if they have the same non-standard representation.
4158
4159 -- For arrays, we simply need to test if the component sizes are the
4160 -- same. Pragma Pack is reflected in modified component sizes, so this
4161 -- check also deals with pragma Pack.
4162
4163 if Is_Array_Type (T1) then
4164 return Component_Size (T1) = Component_Size (T2);
4165
4166 -- Tagged types always have the same representation, because it is not
4167 -- possible to specify different representations for common fields.
4168
4169 elsif Is_Tagged_Type (T1) then
4170 return True;
4171
4172 -- Case of record types
4173
4174 elsif Is_Record_Type (T1) then
4175
4176 -- Packed status must conform
4177
4178 if Is_Packed (T1) /= Is_Packed (T2) then
4179 return False;
4180
4181 -- Otherwise we must check components. Typ2 maybe a constrained
4182 -- subtype with fewer components, so we compare the components
4183 -- of the base types.
4184
4185 else
4186 Record_Case : declare
4187 CD1, CD2 : Entity_Id;
4188
4189 function Same_Rep return Boolean;
4190 -- CD1 and CD2 are either components or discriminants. This
4191 -- function tests whether the two have the same representation
4192
4193 --------------
4194 -- Same_Rep --
4195 --------------
4196
4197 function Same_Rep return Boolean is
4198 begin
4199 if No (Component_Clause (CD1)) then
4200 return No (Component_Clause (CD2));
4201
4202 else
4203 return
4204 Present (Component_Clause (CD2))
4205 and then
4206 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
4207 and then
4208 Esize (CD1) = Esize (CD2);
4209 end if;
4210 end Same_Rep;
4211
4212 -- Start of processing for Record_Case
4213
4214 begin
4215 if Has_Discriminants (T1) then
4216 CD1 := First_Discriminant (T1);
4217 CD2 := First_Discriminant (T2);
4218
4219 -- The number of discriminants may be different if the
4220 -- derived type has fewer (constrained by values). The
4221 -- invisible discriminants retain the representation of
4222 -- the original, so the discrepancy does not per se
4223 -- indicate a different representation.
4224
4225 while Present (CD1)
4226 and then Present (CD2)
4227 loop
4228 if not Same_Rep then
4229 return False;
4230 else
4231 Next_Discriminant (CD1);
4232 Next_Discriminant (CD2);
4233 end if;
4234 end loop;
4235 end if;
4236
4237 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
4238 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
4239
4240 while Present (CD1) loop
4241 if not Same_Rep then
4242 return False;
4243 else
4244 Next_Component (CD1);
4245 Next_Component (CD2);
4246 end if;
4247 end loop;
4248
4249 return True;
4250 end Record_Case;
4251 end if;
4252
4253 -- For enumeration types, we must check each literal to see if the
4254 -- representation is the same. Note that we do not permit enumeration
4255 -- representation clauses for Character and Wide_Character, so these
4256 -- cases were already dealt with.
4257
4258 elsif Is_Enumeration_Type (T1) then
4259
4260 Enumeration_Case : declare
4261 L1, L2 : Entity_Id;
4262
4263 begin
4264 L1 := First_Literal (T1);
4265 L2 := First_Literal (T2);
4266
4267 while Present (L1) loop
4268 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
4269 return False;
4270 else
4271 Next_Literal (L1);
4272 Next_Literal (L2);
4273 end if;
4274 end loop;
4275
4276 return True;
4277
4278 end Enumeration_Case;
4279
4280 -- Any other types have the same representation for these purposes
4281
4282 else
4283 return True;
4284 end if;
4285 end Same_Representation;
4286
4287 --------------------
4288 -- Set_Enum_Esize --
4289 --------------------
4290
4291 procedure Set_Enum_Esize (T : Entity_Id) is
4292 Lo : Uint;
4293 Hi : Uint;
4294 Sz : Nat;
4295
4296 begin
4297 Init_Alignment (T);
4298
4299 -- Find the minimum standard size (8,16,32,64) that fits
4300
4301 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
4302 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
4303
4304 if Lo < 0 then
4305 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
4306 Sz := Standard_Character_Size; -- May be > 8 on some targets
4307
4308 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
4309 Sz := 16;
4310
4311 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
4312 Sz := 32;
4313
4314 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
4315 Sz := 64;
4316 end if;
4317
4318 else
4319 if Hi < Uint_2**08 then
4320 Sz := Standard_Character_Size; -- May be > 8 on some targets
4321
4322 elsif Hi < Uint_2**16 then
4323 Sz := 16;
4324
4325 elsif Hi < Uint_2**32 then
4326 Sz := 32;
4327
4328 else pragma Assert (Hi < Uint_2**63);
4329 Sz := 64;
4330 end if;
4331 end if;
4332
4333 -- That minimum is the proper size unless we have a foreign convention
4334 -- and the size required is 32 or less, in which case we bump the size
4335 -- up to 32. This is required for C and C++ and seems reasonable for
4336 -- all other foreign conventions.
4337
4338 if Has_Foreign_Convention (T)
4339 and then Esize (T) < Standard_Integer_Size
4340 then
4341 Init_Esize (T, Standard_Integer_Size);
4342 else
4343 Init_Esize (T, Sz);
4344 end if;
4345 end Set_Enum_Esize;
4346
4347 ------------------------------
4348 -- Validate_Address_Clauses --
4349 ------------------------------
4350
4351 procedure Validate_Address_Clauses is
4352 begin
4353 for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop
4354 declare
4355 ACCR : Address_Clause_Check_Record
4356 renames Address_Clause_Checks.Table (J);
4357
4358 Expr : Node_Id;
4359
4360 X_Alignment : Uint;
4361 Y_Alignment : Uint;
4362
4363 X_Size : Uint;
4364 Y_Size : Uint;
4365
4366 begin
4367 -- Skip processing of this entry if warning already posted
4368
4369 if not Address_Warning_Posted (ACCR.N) then
4370
4371 Expr := Original_Node (Expression (ACCR.N));
4372
4373 -- Get alignments
4374
4375 X_Alignment := Alignment (ACCR.X);
4376 Y_Alignment := Alignment (ACCR.Y);
4377
4378 -- Similarly obtain sizes
4379
4380 X_Size := Esize (ACCR.X);
4381 Y_Size := Esize (ACCR.Y);
4382
4383 -- Check for large object overlaying smaller one
4384
4385 if Y_Size > Uint_0
4386 and then X_Size > Uint_0
4387 and then X_Size > Y_Size
4388 then
4389 Error_Msg_NE
4390 ("?& overlays smaller object", ACCR.N, ACCR.X);
4391 Error_Msg_N
4392 ("\?program execution may be erroneous", ACCR.N);
4393 Error_Msg_Uint_1 := X_Size;
4394 Error_Msg_NE
4395 ("\?size of & is ^", ACCR.N, ACCR.X);
4396 Error_Msg_Uint_1 := Y_Size;
4397 Error_Msg_NE
4398 ("\?size of & is ^", ACCR.N, ACCR.Y);
4399
4400 -- Check for inadequate alignment, both of the base object
4401 -- and of the offset, if any.
4402
4403 -- Note: we do not check the alignment if we gave a size
4404 -- warning, since it would likely be redundant.
4405
4406 elsif Y_Alignment /= Uint_0
4407 and then (Y_Alignment < X_Alignment
4408 or else (ACCR.Off
4409 and then
4410 Nkind (Expr) = N_Attribute_Reference
4411 and then
4412 Attribute_Name (Expr) = Name_Address
4413 and then
4414 Has_Compatible_Alignment
4415 (ACCR.X, Prefix (Expr))
4416 /= Known_Compatible))
4417 then
4418 Error_Msg_NE
4419 ("?specified address for& may be inconsistent "
4420 & "with alignment",
4421 ACCR.N, ACCR.X);
4422 Error_Msg_N
4423 ("\?program execution may be erroneous (RM 13.3(27))",
4424 ACCR.N);
4425 Error_Msg_Uint_1 := X_Alignment;
4426 Error_Msg_NE
4427 ("\?alignment of & is ^",
4428 ACCR.N, ACCR.X);
4429 Error_Msg_Uint_1 := Y_Alignment;
4430 Error_Msg_NE
4431 ("\?alignment of & is ^",
4432 ACCR.N, ACCR.Y);
4433 if Y_Alignment >= X_Alignment then
4434 Error_Msg_N
4435 ("\?but offset is not multiple of alignment",
4436 ACCR.N);
4437 end if;
4438 end if;
4439 end if;
4440 end;
4441 end loop;
4442 end Validate_Address_Clauses;
4443
4444 -----------------------------------
4445 -- Validate_Unchecked_Conversion --
4446 -----------------------------------
4447
4448 procedure Validate_Unchecked_Conversion
4449 (N : Node_Id;
4450 Act_Unit : Entity_Id)
4451 is
4452 Source : Entity_Id;
4453 Target : Entity_Id;
4454 Vnode : Node_Id;
4455
4456 begin
4457 -- Obtain source and target types. Note that we call Ancestor_Subtype
4458 -- here because the processing for generic instantiation always makes
4459 -- subtypes, and we want the original frozen actual types.
4460
4461 -- If we are dealing with private types, then do the check on their
4462 -- fully declared counterparts if the full declarations have been
4463 -- encountered (they don't have to be visible, but they must exist!)
4464
4465 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
4466
4467 if Is_Private_Type (Source)
4468 and then Present (Underlying_Type (Source))
4469 then
4470 Source := Underlying_Type (Source);
4471 end if;
4472
4473 Target := Ancestor_Subtype (Etype (Act_Unit));
4474
4475 -- If either type is generic, the instantiation happens within a generic
4476 -- unit, and there is nothing to check. The proper check
4477 -- will happen when the enclosing generic is instantiated.
4478
4479 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
4480 return;
4481 end if;
4482
4483 if Is_Private_Type (Target)
4484 and then Present (Underlying_Type (Target))
4485 then
4486 Target := Underlying_Type (Target);
4487 end if;
4488
4489 -- Source may be unconstrained array, but not target
4490
4491 if Is_Array_Type (Target)
4492 and then not Is_Constrained (Target)
4493 then
4494 Error_Msg_N
4495 ("unchecked conversion to unconstrained array not allowed", N);
4496 return;
4497 end if;
4498
4499 -- Warn if conversion between two different convention pointers
4500
4501 if Is_Access_Type (Target)
4502 and then Is_Access_Type (Source)
4503 and then Convention (Target) /= Convention (Source)
4504 and then Warn_On_Unchecked_Conversion
4505 then
4506 -- Give warnings for subprogram pointers only on most targets. The
4507 -- exception is VMS, where data pointers can have different lengths
4508 -- depending on the pointer convention.
4509
4510 if Is_Access_Subprogram_Type (Target)
4511 or else Is_Access_Subprogram_Type (Source)
4512 or else OpenVMS_On_Target
4513 then
4514 Error_Msg_N
4515 ("?conversion between pointers with different conventions!", N);
4516 end if;
4517 end if;
4518
4519 -- Warn if one of the operands is Ada.Calendar.Time. Do not emit a
4520 -- warning when compiling GNAT-related sources.
4521
4522 if Warn_On_Unchecked_Conversion
4523 and then not In_Predefined_Unit (N)
4524 and then RTU_Loaded (Ada_Calendar)
4525 and then
4526 (Chars (Source) = Name_Time
4527 or else
4528 Chars (Target) = Name_Time)
4529 then
4530 -- If Ada.Calendar is loaded and the name of one of the operands is
4531 -- Time, there is a good chance that this is Ada.Calendar.Time.
4532
4533 declare
4534 Calendar_Time : constant Entity_Id :=
4535 Full_View (RTE (RO_CA_Time));
4536 begin
4537 pragma Assert (Present (Calendar_Time));
4538
4539 if Source = Calendar_Time
4540 or else Target = Calendar_Time
4541 then
4542 Error_Msg_N
4543 ("?representation of 'Time values may change between " &
4544 "'G'N'A'T versions", N);
4545 end if;
4546 end;
4547 end if;
4548
4549 -- Make entry in unchecked conversion table for later processing by
4550 -- Validate_Unchecked_Conversions, which will check sizes and alignments
4551 -- (using values set by the back-end where possible). This is only done
4552 -- if the appropriate warning is active.
4553
4554 if Warn_On_Unchecked_Conversion then
4555 Unchecked_Conversions.Append
4556 (New_Val => UC_Entry'
4557 (Eloc => Sloc (N),
4558 Source => Source,
4559 Target => Target));
4560
4561 -- If both sizes are known statically now, then back end annotation
4562 -- is not required to do a proper check but if either size is not
4563 -- known statically, then we need the annotation.
4564
4565 if Known_Static_RM_Size (Source)
4566 and then Known_Static_RM_Size (Target)
4567 then
4568 null;
4569 else
4570 Back_Annotate_Rep_Info := True;
4571 end if;
4572 end if;
4573
4574 -- If unchecked conversion to access type, and access type is declared
4575 -- in the same unit as the unchecked conversion, then set the
4576 -- No_Strict_Aliasing flag (no strict aliasing is implicit in this
4577 -- situation).
4578
4579 if Is_Access_Type (Target) and then
4580 In_Same_Source_Unit (Target, N)
4581 then
4582 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
4583 end if;
4584
4585 -- Generate N_Validate_Unchecked_Conversion node for back end in
4586 -- case the back end needs to perform special validation checks.
4587
4588 -- Shouldn't this be in Exp_Ch13, since the check only gets done
4589 -- if we have full expansion and the back end is called ???
4590
4591 Vnode :=
4592 Make_Validate_Unchecked_Conversion (Sloc (N));
4593 Set_Source_Type (Vnode, Source);
4594 Set_Target_Type (Vnode, Target);
4595
4596 -- If the unchecked conversion node is in a list, just insert before it.
4597 -- If not we have some strange case, not worth bothering about.
4598
4599 if Is_List_Member (N) then
4600 Insert_After (N, Vnode);
4601 end if;
4602 end Validate_Unchecked_Conversion;
4603
4604 ------------------------------------
4605 -- Validate_Unchecked_Conversions --
4606 ------------------------------------
4607
4608 procedure Validate_Unchecked_Conversions is
4609 begin
4610 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
4611 declare
4612 T : UC_Entry renames Unchecked_Conversions.Table (N);
4613
4614 Eloc : constant Source_Ptr := T.Eloc;
4615 Source : constant Entity_Id := T.Source;
4616 Target : constant Entity_Id := T.Target;
4617
4618 Source_Siz : Uint;
4619 Target_Siz : Uint;
4620
4621 begin
4622 -- This validation check, which warns if we have unequal sizes for
4623 -- unchecked conversion, and thus potentially implementation
4624 -- dependent semantics, is one of the few occasions on which we
4625 -- use the official RM size instead of Esize. See description in
4626 -- Einfo "Handling of Type'Size Values" for details.
4627
4628 if Serious_Errors_Detected = 0
4629 and then Known_Static_RM_Size (Source)
4630 and then Known_Static_RM_Size (Target)
4631
4632 -- Don't do the check if warnings off for either type, note the
4633 -- deliberate use of OR here instead of OR ELSE to get the flag
4634 -- Warnings_Off_Used set for both types if appropriate.
4635
4636 and then not (Has_Warnings_Off (Source)
4637 or
4638 Has_Warnings_Off (Target))
4639 then
4640 Source_Siz := RM_Size (Source);
4641 Target_Siz := RM_Size (Target);
4642
4643 if Source_Siz /= Target_Siz then
4644 Error_Msg
4645 ("?types for unchecked conversion have different sizes!",
4646 Eloc);
4647
4648 if All_Errors_Mode then
4649 Error_Msg_Name_1 := Chars (Source);
4650 Error_Msg_Uint_1 := Source_Siz;
4651 Error_Msg_Name_2 := Chars (Target);
4652 Error_Msg_Uint_2 := Target_Siz;
4653 Error_Msg ("\size of % is ^, size of % is ^?", Eloc);
4654
4655 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
4656
4657 if Is_Discrete_Type (Source)
4658 and then Is_Discrete_Type (Target)
4659 then
4660 if Source_Siz > Target_Siz then
4661 Error_Msg
4662 ("\?^ high order bits of source will be ignored!",
4663 Eloc);
4664
4665 elsif Is_Unsigned_Type (Source) then
4666 Error_Msg
4667 ("\?source will be extended with ^ high order " &
4668 "zero bits?!", Eloc);
4669
4670 else
4671 Error_Msg
4672 ("\?source will be extended with ^ high order " &
4673 "sign bits!",
4674 Eloc);
4675 end if;
4676
4677 elsif Source_Siz < Target_Siz then
4678 if Is_Discrete_Type (Target) then
4679 if Bytes_Big_Endian then
4680 Error_Msg
4681 ("\?target value will include ^ undefined " &
4682 "low order bits!",
4683 Eloc);
4684 else
4685 Error_Msg
4686 ("\?target value will include ^ undefined " &
4687 "high order bits!",
4688 Eloc);
4689 end if;
4690
4691 else
4692 Error_Msg
4693 ("\?^ trailing bits of target value will be " &
4694 "undefined!", Eloc);
4695 end if;
4696
4697 else pragma Assert (Source_Siz > Target_Siz);
4698 Error_Msg
4699 ("\?^ trailing bits of source will be ignored!",
4700 Eloc);
4701 end if;
4702 end if;
4703 end if;
4704 end if;
4705
4706 -- If both types are access types, we need to check the alignment.
4707 -- If the alignment of both is specified, we can do it here.
4708
4709 if Serious_Errors_Detected = 0
4710 and then Ekind (Source) in Access_Kind
4711 and then Ekind (Target) in Access_Kind
4712 and then Target_Strict_Alignment
4713 and then Present (Designated_Type (Source))
4714 and then Present (Designated_Type (Target))
4715 then
4716 declare
4717 D_Source : constant Entity_Id := Designated_Type (Source);
4718 D_Target : constant Entity_Id := Designated_Type (Target);
4719
4720 begin
4721 if Known_Alignment (D_Source)
4722 and then Known_Alignment (D_Target)
4723 then
4724 declare
4725 Source_Align : constant Uint := Alignment (D_Source);
4726 Target_Align : constant Uint := Alignment (D_Target);
4727
4728 begin
4729 if Source_Align < Target_Align
4730 and then not Is_Tagged_Type (D_Source)
4731
4732 -- Suppress warning if warnings suppressed on either
4733 -- type or either designated type. Note the use of
4734 -- OR here instead of OR ELSE. That is intentional,
4735 -- we would like to set flag Warnings_Off_Used in
4736 -- all types for which warnings are suppressed.
4737
4738 and then not (Has_Warnings_Off (D_Source)
4739 or
4740 Has_Warnings_Off (D_Target)
4741 or
4742 Has_Warnings_Off (Source)
4743 or
4744 Has_Warnings_Off (Target))
4745 then
4746 Error_Msg_Uint_1 := Target_Align;
4747 Error_Msg_Uint_2 := Source_Align;
4748 Error_Msg_Node_1 := D_Target;
4749 Error_Msg_Node_2 := D_Source;
4750 Error_Msg
4751 ("?alignment of & (^) is stricter than " &
4752 "alignment of & (^)!", Eloc);
4753 Error_Msg
4754 ("\?resulting access value may have invalid " &
4755 "alignment!", Eloc);
4756 end if;
4757 end;
4758 end if;
4759 end;
4760 end if;
4761 end;
4762 end loop;
4763 end Validate_Unchecked_Conversions;
4764
4765 end Sem_Ch13;
Mirror of the offical gcc git repository hosted at gcc.gnu.org