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* tree-ssa-pre.c (grand_bitmap_obstack): New.
[official-gcc.git] / gcc / ada / sem_ch13.adb
blob9b8518d966a0581b80fc24b0d60f5be2c60c06e2
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) 1992-2004, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
26
27 with Atree; use Atree;
28 with Checks; use Checks;
29 with Einfo; use Einfo;
30 with Errout; use Errout;
31 with Exp_Tss; use Exp_Tss;
32 with Exp_Util; use Exp_Util;
33 with Lib; use Lib;
34 with Nlists; use Nlists;
35 with Nmake; use Nmake;
36 with Opt; use Opt;
37 with Rtsfind; use Rtsfind;
38 with Sem; use Sem;
39 with Sem_Ch8; use Sem_Ch8;
40 with Sem_Eval; use Sem_Eval;
41 with Sem_Res; use Sem_Res;
42 with Sem_Type; use Sem_Type;
43 with Sem_Util; use Sem_Util;
44 with Snames; use Snames;
45 with Stand; use Stand;
46 with Sinfo; use Sinfo;
47 with Table;
48 with Targparm; use Targparm;
49 with Ttypes; use Ttypes;
50 with Tbuild; use Tbuild;
51 with Urealp; use Urealp;
52
53 with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
54
55 package body Sem_Ch13 is
56
57 SSU : constant Pos := System_Storage_Unit;
58 -- Convenient short hand for commonly used constant
59
60 -----------------------
61 -- Local Subprograms --
62 -----------------------
63
64 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id);
65 -- This routine is called after setting the Esize of type entity Typ.
66 -- The purpose is to deal with the situation where an aligment has been
67 -- inherited from a derived type that is no longer appropriate for the
68 -- new Esize value. In this case, we reset the Alignment to unknown.
69
70 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id);
71 -- Given two entities for record components or discriminants, checks
72 -- if they hav overlapping component clauses and issues errors if so.
73
74 function Get_Alignment_Value (Expr : Node_Id) return Uint;
75 -- Given the expression for an alignment value, returns the corresponding
76 -- Uint value. If the value is inappropriate, then error messages are
77 -- posted as required, and a value of No_Uint is returned.
78
79 function Is_Operational_Item (N : Node_Id) return Boolean;
80 -- A specification for a stream attribute is allowed before the full
81 -- type is declared, as explained in AI-00137 and the corrigendum.
82 -- Attributes that do not specify a representation characteristic are
83 -- operational attributes.
84
85 function Address_Aliased_Entity (N : Node_Id) return Entity_Id;
86 -- If expression N is of the form E'Address, return E.
87
88 procedure Mark_Aliased_Address_As_Volatile (N : Node_Id);
89 -- This is used for processing of an address representation clause. If
90 -- the expression N is of the form of K'Address, then the entity that
91 -- is associated with K is marked as volatile.
92
93 procedure New_Stream_Function
94 (N : Node_Id;
95 Ent : Entity_Id;
96 Subp : Entity_Id;
97 Nam : TSS_Name_Type);
98 -- Create a function renaming of a given stream attribute to the
99 -- designated subprogram and then in the tagged case, provide this as
100 -- a primitive operation, or in the non-tagged case make an appropriate
101 -- TSS entry. Used for Input. This is more properly an expansion activity
102 -- than just semantics, but the presence of user-defined stream functions
103 -- for limited types is a legality check, which is why this takes place
104 -- here rather than in exp_ch13, where it was previously. Nam indicates
105 -- the name of the TSS function to be generated.
106 --
107 -- To avoid elaboration anomalies with freeze nodes, for untagged types
108 -- we generate both a subprogram declaration and a subprogram renaming
109 -- declaration, so that the attribute specification is handled as a
110 -- renaming_as_body. For tagged types, the specification is one of the
111 -- primitive specs.
112
113 procedure New_Stream_Procedure
114 (N : Node_Id;
115 Ent : Entity_Id;
116 Subp : Entity_Id;
117 Nam : TSS_Name_Type;
118 Out_P : Boolean := False);
119 -- Create a procedure renaming of a given stream attribute to the
120 -- designated subprogram and then in the tagged case, provide this as
121 -- a primitive operation, or in the non-tagged case make an appropriate
122 -- TSS entry. Used for Read, Output, Write. Nam indicates the name of
123 -- the TSS procedure to be generated.
124
125 ----------------------------------------------
126 -- Table for Validate_Unchecked_Conversions --
127 ----------------------------------------------
128
129 -- The following table collects unchecked conversions for validation.
130 -- Entries are made by Validate_Unchecked_Conversion and then the
131 -- call to Validate_Unchecked_Conversions does the actual error
132 -- checking and posting of warnings. The reason for this delayed
133 -- processing is to take advantage of back-annotations of size and
134 -- alignment values peformed by the back end.
135
136 type UC_Entry is record
137 Enode : Node_Id; -- node used for posting warnings
138 Source : Entity_Id; -- source type for unchecked conversion
139 Target : Entity_Id; -- target type for unchecked conversion
140 end record;
141
142 package Unchecked_Conversions is new Table.Table (
143 Table_Component_Type => UC_Entry,
144 Table_Index_Type => Int,
145 Table_Low_Bound => 1,
146 Table_Initial => 50,
147 Table_Increment => 200,
148 Table_Name => "Unchecked_Conversions");
149
150 ----------------------------
151 -- Address_Aliased_Entity --
152 ----------------------------
153
154 function Address_Aliased_Entity (N : Node_Id) return Entity_Id is
155 begin
156 if Nkind (N) = N_Attribute_Reference
157 and then Attribute_Name (N) = Name_Address
158 then
159 declare
160 Nam : Node_Id := Prefix (N);
161 begin
162 while False
163 or else Nkind (Nam) = N_Selected_Component
164 or else Nkind (Nam) = N_Indexed_Component
165 loop
166 Nam := Prefix (Nam);
167 end loop;
168
169 if Is_Entity_Name (Nam) then
170 return Entity (Nam);
171 end if;
172 end;
173 end if;
174
175 return Empty;
176 end Address_Aliased_Entity;
177
178 --------------------------------------
179 -- Alignment_Check_For_Esize_Change --
180 --------------------------------------
181
182 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is
183 begin
184 -- If the alignment is known, and not set by a rep clause, and is
185 -- inconsistent with the size being set, then reset it to unknown,
186 -- we assume in this case that the size overrides the inherited
187 -- alignment, and that the alignment must be recomputed.
188
189 if Known_Alignment (Typ)
190 and then not Has_Alignment_Clause (Typ)
191 and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0
192 then
193 Init_Alignment (Typ);
194 end if;
195 end Alignment_Check_For_Esize_Change;
196
197 -----------------------
198 -- Analyze_At_Clause --
199 -----------------------
200
201 -- An at clause is replaced by the corresponding Address attribute
202 -- definition clause that is the preferred approach in Ada 95.
203
204 procedure Analyze_At_Clause (N : Node_Id) is
205 begin
206 if Warn_On_Obsolescent_Feature then
207 Error_Msg_N
208 ("at clause is an obsolescent feature ('R'M 'J.7(2))?", N);
209 Error_Msg_N
210 ("|use address attribute definition clause instead?", N);
211 end if;
212
213 Rewrite (N,
214 Make_Attribute_Definition_Clause (Sloc (N),
215 Name => Identifier (N),
216 Chars => Name_Address,
217 Expression => Expression (N)));
218 Analyze_Attribute_Definition_Clause (N);
219 end Analyze_At_Clause;
220
221 -----------------------------------------
222 -- Analyze_Attribute_Definition_Clause --
223 -----------------------------------------
224
225 procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is
226 Loc : constant Source_Ptr := Sloc (N);
227 Nam : constant Node_Id := Name (N);
228 Attr : constant Name_Id := Chars (N);
229 Expr : constant Node_Id := Expression (N);
230 Id : constant Attribute_Id := Get_Attribute_Id (Attr);
231 Ent : Entity_Id;
232 U_Ent : Entity_Id;
233
234 FOnly : Boolean := False;
235 -- Reset to True for subtype specific attribute (Alignment, Size)
236 -- and for stream attributes, i.e. those cases where in the call
237 -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing
238 -- rules are checked. Note that the case of stream attributes is not
239 -- clear from the RM, but see AI95-00137. Also, the RM seems to
240 -- disallow Storage_Size for derived task types, but that is also
241 -- clearly unintentional.
242
243 begin
244 Analyze (Nam);
245 Ent := Entity (Nam);
246
247 if Rep_Item_Too_Early (Ent, N) then
248 return;
249 end if;
250
251 -- Rep clause applies to full view of incomplete type or private type
252 -- if we have one (if not, this is a premature use of the type).
253 -- However, certain semantic checks need to be done on the specified
254 -- entity (i.e. the private view), so we save it in Ent.
255
256 if Is_Private_Type (Ent)
257 and then Is_Derived_Type (Ent)
258 and then not Is_Tagged_Type (Ent)
259 and then No (Full_View (Ent))
260 then
261 -- If this is a private type whose completion is a derivation
262 -- from another private type, there is no full view, and the
263 -- attribute belongs to the type itself, not its underlying parent.
264
265 U_Ent := Ent;
266
267 elsif Ekind (Ent) = E_Incomplete_Type then
268
269 -- The attribute applies to the full view, set the entity
270 -- of the attribute definition accordingly.
271
272 Ent := Underlying_Type (Ent);
273 U_Ent := Ent;
274 Set_Entity (Nam, Ent);
275
276 else
277 U_Ent := Underlying_Type (Ent);
278 end if;
279
280 -- Complete other routine error checks
281
282 if Etype (Nam) = Any_Type then
283 return;
284
285 elsif Scope (Ent) /= Current_Scope then
286 Error_Msg_N ("entity must be declared in this scope", Nam);
287 return;
288
289 elsif No (U_Ent) then
290 U_Ent := Ent;
291
292 elsif Is_Type (U_Ent)
293 and then not Is_First_Subtype (U_Ent)
294 and then Id /= Attribute_Object_Size
295 and then Id /= Attribute_Value_Size
296 and then not From_At_Mod (N)
297 then
298 Error_Msg_N ("cannot specify attribute for subtype", Nam);
299 return;
300
301 end if;
302
303 -- Switch on particular attribute
304
305 case Id is
306
307 -------------
308 -- Address --
309 -------------
310
311 -- Address attribute definition clause
312
313 when Attribute_Address => Address : begin
314 Analyze_And_Resolve (Expr, RTE (RE_Address));
315
316 if Present (Address_Clause (U_Ent)) then
317 Error_Msg_N ("address already given for &", Nam);
318
319 -- Case of address clause for subprogram
320
321 elsif Is_Subprogram (U_Ent) then
322 if Has_Homonym (U_Ent) then
323 Error_Msg_N
324 ("address clause cannot be given " &
325 "for overloaded subprogram",
326 Nam);
327 end if;
328
329 -- For subprograms, all address clauses are permitted,
330 -- and we mark the subprogram as having a deferred freeze
331 -- so that Gigi will not elaborate it too soon.
332
333 -- Above needs more comments, what is too soon about???
334
335 Set_Has_Delayed_Freeze (U_Ent);
336
337 -- Case of address clause for entry
338
339 elsif Ekind (U_Ent) = E_Entry then
340 if Nkind (Parent (N)) = N_Task_Body then
341 Error_Msg_N
342 ("entry address must be specified in task spec", Nam);
343 end if;
344
345 -- For entries, we require a constant address
346
347 Check_Constant_Address_Clause (Expr, U_Ent);
348
349 if Is_Task_Type (Scope (U_Ent))
350 and then Comes_From_Source (Scope (U_Ent))
351 then
352 Error_Msg_N
353 ("?entry address declared for entry in task type", N);
354 Error_Msg_N
355 ("\?only one task can be declared of this type", N);
356 end if;
357
358 if Warn_On_Obsolescent_Feature then
359 Error_Msg_N
360 ("attaching interrupt to task entry is an " &
361 "obsolescent feature ('R'M 'J.7.1)?", N);
362 Error_Msg_N
363 ("|use interrupt procedure instead?", N);
364 end if;
365
366 -- Case of an address clause for a controlled object:
367 -- erroneous execution.
368
369 elsif Is_Controlled (Etype (U_Ent)) then
370 Error_Msg_NE
371 ("?controlled object& must not be overlaid", Nam, U_Ent);
372 Error_Msg_N
373 ("\?Program_Error will be raised at run time", Nam);
374 Insert_Action (Declaration_Node (U_Ent),
375 Make_Raise_Program_Error (Loc,
376 Reason => PE_Overlaid_Controlled_Object));
377
378 -- Case of address clause for a (non-controlled) object
379
380 elsif
381 Ekind (U_Ent) = E_Variable
382 or else
383 Ekind (U_Ent) = E_Constant
384 then
385 declare
386 Expr : constant Node_Id := Expression (N);
387 Aent : constant Entity_Id := Address_Aliased_Entity (Expr);
388
389 begin
390 -- Exported variables cannot have an address clause,
391 -- because this cancels the effect of the pragma Export
392
393 if Is_Exported (U_Ent) then
394 Error_Msg_N
395 ("cannot export object with address clause", Nam);
396
397 -- Overlaying controlled objects is erroneous
398
399 elsif Present (Aent)
400 and then Is_Controlled (Etype (Aent))
401 then
402 Error_Msg_N
403 ("?controlled object must not be overlaid", Expr);
404 Error_Msg_N
405 ("\?Program_Error will be raised at run time", Expr);
406 Insert_Action (Declaration_Node (U_Ent),
407 Make_Raise_Program_Error (Loc,
408 Reason => PE_Overlaid_Controlled_Object));
409
410 elsif Present (Aent)
411 and then Ekind (U_Ent) = E_Constant
412 and then Ekind (Aent) /= E_Constant
413 then
414 Error_Msg_N ("constant overlays a variable?", Expr);
415
416 elsif Present (Renamed_Object (U_Ent)) then
417 Error_Msg_N
418 ("address clause not allowed"
419 & " for a renaming declaration ('R'M 13.1(6))", Nam);
420
421 -- Imported variables can have an address clause, but then
422 -- the import is pretty meaningless except to suppress
423 -- initializations, so we do not need such variables to
424 -- be statically allocated (and in fact it causes trouble
425 -- if the address clause is a local value).
426
427 elsif Is_Imported (U_Ent) then
428 Set_Is_Statically_Allocated (U_Ent, False);
429 end if;
430
431 -- We mark a possible modification of a variable with an
432 -- address clause, since it is likely aliasing is occurring.
433
434 Note_Possible_Modification (Nam);
435
436 -- Here we are checking for explicit overlap of one
437 -- variable by another, and if we find this, then we
438 -- mark the overlapped variable as also being aliased.
439
440 -- First case is where we have an explicit
441
442 -- for J'Address use K'Address;
443
444 -- In this case, we mark K as volatile
445
446 Mark_Aliased_Address_As_Volatile (Expr);
447
448 -- Second case is where we have a constant whose
449 -- definition is of the form of an adress as in:
450
451 -- A : constant Address := K'Address;
452 -- ...
453 -- for B'Address use A;
454
455 -- In this case we also mark K as volatile
456
457 if Is_Entity_Name (Expr) then
458 declare
459 Ent : constant Entity_Id := Entity (Expr);
460 Decl : constant Node_Id := Declaration_Node (Ent);
461
462 begin
463 if Ekind (Ent) = E_Constant
464 and then Nkind (Decl) = N_Object_Declaration
465 and then Present (Expression (Decl))
466 then
467 Mark_Aliased_Address_As_Volatile
468 (Expression (Decl));
469 end if;
470 end;
471 end if;
472
473 -- Legality checks on the address clause for initialized
474 -- objects is deferred until the freeze point, because
475 -- a subsequent pragma might indicate that the object is
476 -- imported and thus not initialized.
477
478 Set_Has_Delayed_Freeze (U_Ent);
479
480 if Is_Exported (U_Ent) then
481 Error_Msg_N
482 ("& cannot be exported if an address clause is given",
483 Nam);
484 Error_Msg_N
485 ("\define and export a variable " &
486 "that holds its address instead",
487 Nam);
488 end if;
489
490 -- Entity has delayed freeze, so we will generate
491 -- an alignment check at the freeze point.
492
493 Set_Check_Address_Alignment
494 (N, not Range_Checks_Suppressed (U_Ent));
495
496 -- Kill the size check code, since we are not allocating
497 -- the variable, it is somewhere else.
498
499 Kill_Size_Check_Code (U_Ent);
500 end;
501
502 -- Not a valid entity for an address clause
503
504 else
505 Error_Msg_N ("address cannot be given for &", Nam);
506 end if;
507 end Address;
508
509 ---------------
510 -- Alignment --
511 ---------------
512
513 -- Alignment attribute definition clause
514
515 when Attribute_Alignment => Alignment_Block : declare
516 Align : constant Uint := Get_Alignment_Value (Expr);
517
518 begin
519 FOnly := True;
520
521 if not Is_Type (U_Ent)
522 and then Ekind (U_Ent) /= E_Variable
523 and then Ekind (U_Ent) /= E_Constant
524 then
525 Error_Msg_N ("alignment cannot be given for &", Nam);
526
527 elsif Has_Alignment_Clause (U_Ent) then
528 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
529 Error_Msg_N ("alignment clause previously given#", N);
530
531 elsif Align /= No_Uint then
532 Set_Has_Alignment_Clause (U_Ent);
533 Set_Alignment (U_Ent, Align);
534 end if;
535 end Alignment_Block;
536
537 ---------------
538 -- Bit_Order --
539 ---------------
540
541 -- Bit_Order attribute definition clause
542
543 when Attribute_Bit_Order => Bit_Order : declare
544 begin
545 if not Is_Record_Type (U_Ent) then
546 Error_Msg_N
547 ("Bit_Order can only be defined for record type", Nam);
548
549 else
550 Analyze_And_Resolve (Expr, RTE (RE_Bit_Order));
551
552 if Etype (Expr) = Any_Type then
553 return;
554
555 elsif not Is_Static_Expression (Expr) then
556 Flag_Non_Static_Expr
557 ("Bit_Order requires static expression!", Expr);
558
559 else
560 if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then
561 Set_Reverse_Bit_Order (U_Ent, True);
562 end if;
563 end if;
564 end if;
565 end Bit_Order;
566
567 --------------------
568 -- Component_Size --
569 --------------------
570
571 -- Component_Size attribute definition clause
572
573 when Attribute_Component_Size => Component_Size_Case : declare
574 Csize : constant Uint := Static_Integer (Expr);
575 Btype : Entity_Id;
576 Biased : Boolean;
577 New_Ctyp : Entity_Id;
578 Decl : Node_Id;
579
580 begin
581 if not Is_Array_Type (U_Ent) then
582 Error_Msg_N ("component size requires array type", Nam);
583 return;
584 end if;
585
586 Btype := Base_Type (U_Ent);
587
588 if Has_Component_Size_Clause (Btype) then
589 Error_Msg_N
590 ("component size clase for& previously given", Nam);
591
592 elsif Csize /= No_Uint then
593 Check_Size (Expr, Component_Type (Btype), Csize, Biased);
594
595 if Has_Aliased_Components (Btype)
596 and then Csize < 32
597 and then Csize /= 8
598 and then Csize /= 16
599 then
600 Error_Msg_N
601 ("component size incorrect for aliased components", N);
602 return;
603 end if;
604
605 -- For the biased case, build a declaration for a subtype
606 -- that will be used to represent the biased subtype that
607 -- reflects the biased representation of components. We need
608 -- this subtype to get proper conversions on referencing
609 -- elements of the array.
610
611 if Biased then
612 New_Ctyp :=
613 Make_Defining_Identifier (Loc,
614 Chars => New_External_Name (Chars (U_Ent), 'C', 0, 'T'));
615
616 Decl :=
617 Make_Subtype_Declaration (Loc,
618 Defining_Identifier => New_Ctyp,
619 Subtype_Indication =>
620 New_Occurrence_Of (Component_Type (Btype), Loc));
621
622 Set_Parent (Decl, N);
623 Analyze (Decl, Suppress => All_Checks);
624
625 Set_Has_Delayed_Freeze (New_Ctyp, False);
626 Set_Esize (New_Ctyp, Csize);
627 Set_RM_Size (New_Ctyp, Csize);
628 Init_Alignment (New_Ctyp);
629 Set_Has_Biased_Representation (New_Ctyp, True);
630 Set_Is_Itype (New_Ctyp, True);
631 Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
632
633 Set_Component_Type (Btype, New_Ctyp);
634 end if;
635
636 Set_Component_Size (Btype, Csize);
637 Set_Has_Component_Size_Clause (Btype, True);
638 Set_Has_Non_Standard_Rep (Btype, True);
639 end if;
640 end Component_Size_Case;
641
642 ------------------
643 -- External_Tag --
644 ------------------
645
646 when Attribute_External_Tag => External_Tag :
647 begin
648 if not Is_Tagged_Type (U_Ent) then
649 Error_Msg_N ("should be a tagged type", Nam);
650 end if;
651
652 Analyze_And_Resolve (Expr, Standard_String);
653
654 if not Is_Static_Expression (Expr) then
655 Flag_Non_Static_Expr
656 ("static string required for tag name!", Nam);
657 end if;
658
659 Set_Has_External_Tag_Rep_Clause (U_Ent);
660 end External_Tag;
661
662 -----------
663 -- Input --
664 -----------
665
666 when Attribute_Input => Input : declare
667 Subp : Entity_Id := Empty;
668 I : Interp_Index;
669 It : Interp;
670 Pnam : Entity_Id;
671
672 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
673 -- Return true if the entity is a function with an appropriate
674 -- profile for the Input attribute.
675
676 ----------------------
677 -- Has_Good_Profile --
678 ----------------------
679
680 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
681 F : Entity_Id;
682 Ok : Boolean := False;
683
684 begin
685 if Ekind (Subp) = E_Function then
686 F := First_Formal (Subp);
687
688 if Present (F) and then No (Next_Formal (F)) then
689 if Ekind (Etype (F)) = E_Anonymous_Access_Type
690 and then
691 Designated_Type (Etype (F)) =
692 Class_Wide_Type (RTE (RE_Root_Stream_Type))
693 then
694 Ok := Base_Type (Etype (Subp)) = Base_Type (Ent);
695 end if;
696 end if;
697 end if;
698
699 return Ok;
700 end Has_Good_Profile;
701
702 -- Start of processing for Input attribute definition
703
704 begin
705 FOnly := True;
706
707 if not Is_Type (U_Ent) then
708 Error_Msg_N ("local name must be a subtype", Nam);
709 return;
710
711 else
712 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Input);
713
714 if Present (Pnam)
715 and then Base_Type (Etype (Pnam)) = Base_Type (U_Ent)
716 then
717 Error_Msg_Sloc := Sloc (Pnam);
718 Error_Msg_N ("input attribute already defined #", Nam);
719 return;
720 end if;
721 end if;
722
723 Analyze (Expr);
724
725 if Is_Entity_Name (Expr) then
726 if not Is_Overloaded (Expr) then
727 if Has_Good_Profile (Entity (Expr)) then
728 Subp := Entity (Expr);
729 end if;
730
731 else
732 Get_First_Interp (Expr, I, It);
733
734 while Present (It.Nam) loop
735 if Has_Good_Profile (It.Nam) then
736 Subp := It.Nam;
737 exit;
738 end if;
739
740 Get_Next_Interp (I, It);
741 end loop;
742 end if;
743 end if;
744
745 if Present (Subp) then
746 Set_Entity (Expr, Subp);
747 Set_Etype (Expr, Etype (Subp));
748 New_Stream_Function (N, U_Ent, Subp, TSS_Stream_Input);
749 else
750 Error_Msg_N ("incorrect expression for input attribute", Expr);
751 return;
752 end if;
753 end Input;
754
755 -------------------
756 -- Machine_Radix --
757 -------------------
758
759 -- Machine radix attribute definition clause
760
761 when Attribute_Machine_Radix => Machine_Radix : declare
762 Radix : constant Uint := Static_Integer (Expr);
763
764 begin
765 if not Is_Decimal_Fixed_Point_Type (U_Ent) then
766 Error_Msg_N ("decimal fixed-point type expected for &", Nam);
767
768 elsif Has_Machine_Radix_Clause (U_Ent) then
769 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
770 Error_Msg_N ("machine radix clause previously given#", N);
771
772 elsif Radix /= No_Uint then
773 Set_Has_Machine_Radix_Clause (U_Ent);
774 Set_Has_Non_Standard_Rep (Base_Type (U_Ent));
775
776 if Radix = 2 then
777 null;
778 elsif Radix = 10 then
779 Set_Machine_Radix_10 (U_Ent);
780 else
781 Error_Msg_N ("machine radix value must be 2 or 10", Expr);
782 end if;
783 end if;
784 end Machine_Radix;
785
786 -----------------
787 -- Object_Size --
788 -----------------
789
790 -- Object_Size attribute definition clause
791
792 when Attribute_Object_Size => Object_Size : declare
793 Size : constant Uint := Static_Integer (Expr);
794 Biased : Boolean;
795
796 begin
797 if not Is_Type (U_Ent) then
798 Error_Msg_N ("Object_Size cannot be given for &", Nam);
799
800 elsif Has_Object_Size_Clause (U_Ent) then
801 Error_Msg_N ("Object_Size already given for &", Nam);
802
803 else
804 Check_Size (Expr, U_Ent, Size, Biased);
805
806 if Size /= 8
807 and then
808 Size /= 16
809 and then
810 Size /= 32
811 and then
812 UI_Mod (Size, 64) /= 0
813 then
814 Error_Msg_N
815 ("Object_Size must be 8, 16, 32, or multiple of 64",
816 Expr);
817 end if;
818
819 Set_Esize (U_Ent, Size);
820 Set_Has_Object_Size_Clause (U_Ent);
821 Alignment_Check_For_Esize_Change (U_Ent);
822 end if;
823 end Object_Size;
824
825 ------------
826 -- Output --
827 ------------
828
829 when Attribute_Output => Output : declare
830 Subp : Entity_Id := Empty;
831 I : Interp_Index;
832 It : Interp;
833 Pnam : Entity_Id;
834
835 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
836 -- Return true if the entity is a procedure with an
837 -- appropriate profile for the output attribute.
838
839 ----------------------
840 -- Has_Good_Profile --
841 ----------------------
842
843 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
844 F : Entity_Id;
845 Ok : Boolean := False;
846
847 begin
848 if Ekind (Subp) = E_Procedure then
849 F := First_Formal (Subp);
850
851 if Present (F) then
852 if Ekind (Etype (F)) = E_Anonymous_Access_Type
853 and then
854 Designated_Type (Etype (F)) =
855 Class_Wide_Type (RTE (RE_Root_Stream_Type))
856 then
857 Next_Formal (F);
858 Ok := Present (F)
859 and then Parameter_Mode (F) = E_In_Parameter
860 and then Base_Type (Etype (F)) = Base_Type (Ent)
861 and then No (Next_Formal (F));
862 end if;
863 end if;
864 end if;
865
866 return Ok;
867 end Has_Good_Profile;
868
869 -- Start of processing for Output attribute definition
870
871 begin
872 FOnly := True;
873
874 if not Is_Type (U_Ent) then
875 Error_Msg_N ("local name must be a subtype", Nam);
876 return;
877
878 else
879 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Output);
880
881 if Present (Pnam)
882 and then
883 Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
884 = Base_Type (U_Ent)
885 then
886 Error_Msg_Sloc := Sloc (Pnam);
887 Error_Msg_N ("output attribute already defined #", Nam);
888 return;
889 end if;
890 end if;
891
892 Analyze (Expr);
893
894 if Is_Entity_Name (Expr) then
895 if not Is_Overloaded (Expr) then
896 if Has_Good_Profile (Entity (Expr)) then
897 Subp := Entity (Expr);
898 end if;
899
900 else
901 Get_First_Interp (Expr, I, It);
902
903 while Present (It.Nam) loop
904 if Has_Good_Profile (It.Nam) then
905 Subp := It.Nam;
906 exit;
907 end if;
908
909 Get_Next_Interp (I, It);
910 end loop;
911 end if;
912 end if;
913
914 if Present (Subp) then
915 Set_Entity (Expr, Subp);
916 Set_Etype (Expr, Etype (Subp));
917 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Output);
918 else
919 Error_Msg_N ("incorrect expression for output attribute", Expr);
920 return;
921 end if;
922 end Output;
923
924 ----------
925 -- Read --
926 ----------
927
928 when Attribute_Read => Read : declare
929 Subp : Entity_Id := Empty;
930 I : Interp_Index;
931 It : Interp;
932 Pnam : Entity_Id;
933
934 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
935 -- Return true if the entity is a procedure with an appropriate
936 -- profile for the Read attribute.
937
938 ----------------------
939 -- Has_Good_Profile --
940 ----------------------
941
942 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
943 F : Entity_Id;
944 Ok : Boolean := False;
945
946 begin
947 if Ekind (Subp) = E_Procedure then
948 F := First_Formal (Subp);
949
950 if Present (F) then
951 if Ekind (Etype (F)) = E_Anonymous_Access_Type
952 and then
953 Designated_Type (Etype (F)) =
954 Class_Wide_Type (RTE (RE_Root_Stream_Type))
955 then
956 Next_Formal (F);
957 Ok := Present (F)
958 and then Parameter_Mode (F) = E_Out_Parameter
959 and then Base_Type (Etype (F)) = Base_Type (Ent)
960 and then No (Next_Formal (F));
961 end if;
962 end if;
963 end if;
964
965 return Ok;
966 end Has_Good_Profile;
967
968 -- Start of processing for Read attribute definition
969
970 begin
971 FOnly := True;
972
973 if not Is_Type (U_Ent) then
974 Error_Msg_N ("local name must be a subtype", Nam);
975 return;
976
977 else
978 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Read);
979
980 if Present (Pnam)
981 and then Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
982 = Base_Type (U_Ent)
983 then
984 Error_Msg_Sloc := Sloc (Pnam);
985 Error_Msg_N ("read attribute already defined #", Nam);
986 return;
987 end if;
988 end if;
989
990 Analyze (Expr);
991
992 if Is_Entity_Name (Expr) then
993 if not Is_Overloaded (Expr) then
994 if Has_Good_Profile (Entity (Expr)) then
995 Subp := Entity (Expr);
996 end if;
997
998 else
999 Get_First_Interp (Expr, I, It);
1000
1001 while Present (It.Nam) loop
1002 if Has_Good_Profile (It.Nam) then
1003 Subp := It.Nam;
1004 exit;
1005 end if;
1006
1007 Get_Next_Interp (I, It);
1008 end loop;
1009 end if;
1010 end if;
1011
1012 if Present (Subp) then
1013 Set_Entity (Expr, Subp);
1014 Set_Etype (Expr, Etype (Subp));
1015 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Read, True);
1016 else
1017 Error_Msg_N ("incorrect expression for read attribute", Expr);
1018 return;
1019 end if;
1020 end Read;
1021
1022 ----------
1023 -- Size --
1024 ----------
1025
1026 -- Size attribute definition clause
1027
1028 when Attribute_Size => Size : declare
1029 Size : constant Uint := Static_Integer (Expr);
1030 Etyp : Entity_Id;
1031 Biased : Boolean;
1032
1033 begin
1034 FOnly := True;
1035
1036 if Has_Size_Clause (U_Ent) then
1037 Error_Msg_N ("size already given for &", Nam);
1038
1039 elsif not Is_Type (U_Ent)
1040 and then Ekind (U_Ent) /= E_Variable
1041 and then Ekind (U_Ent) /= E_Constant
1042 then
1043 Error_Msg_N ("size cannot be given for &", Nam);
1044
1045 elsif Is_Array_Type (U_Ent)
1046 and then not Is_Constrained (U_Ent)
1047 then
1048 Error_Msg_N
1049 ("size cannot be given for unconstrained array", Nam);
1050
1051 elsif Size /= No_Uint then
1052 if Is_Type (U_Ent) then
1053 Etyp := U_Ent;
1054 else
1055 Etyp := Etype (U_Ent);
1056 end if;
1057
1058 -- Check size, note that Gigi is in charge of checking
1059 -- that the size of an array or record type is OK. Also
1060 -- we do not check the size in the ordinary fixed-point
1061 -- case, since it is too early to do so (there may be a
1062 -- subsequent small clause that affects the size). We can
1063 -- check the size if a small clause has already been given.
1064
1065 if not Is_Ordinary_Fixed_Point_Type (U_Ent)
1066 or else Has_Small_Clause (U_Ent)
1067 then
1068 Check_Size (Expr, Etyp, Size, Biased);
1069 Set_Has_Biased_Representation (U_Ent, Biased);
1070 end if;
1071
1072 -- For types set RM_Size and Esize if possible
1073
1074 if Is_Type (U_Ent) then
1075 Set_RM_Size (U_Ent, Size);
1076
1077 -- For scalar types, increase Object_Size to power of 2,
1078 -- but not less than a storage unit in any case (i.e.,
1079 -- normally this means it will be byte addressable).
1080
1081 if Is_Scalar_Type (U_Ent) then
1082 if Size <= System_Storage_Unit then
1083 Init_Esize (U_Ent, System_Storage_Unit);
1084 elsif Size <= 16 then
1085 Init_Esize (U_Ent, 16);
1086 elsif Size <= 32 then
1087 Init_Esize (U_Ent, 32);
1088 else
1089 Set_Esize (U_Ent, (Size + 63) / 64 * 64);
1090 end if;
1091
1092 -- For all other types, object size = value size. The
1093 -- backend will adjust as needed.
1094
1095 else
1096 Set_Esize (U_Ent, Size);
1097 end if;
1098
1099 Alignment_Check_For_Esize_Change (U_Ent);
1100
1101 -- For objects, set Esize only
1102
1103 else
1104 if Is_Elementary_Type (Etyp) then
1105 if Size /= System_Storage_Unit
1106 and then
1107 Size /= System_Storage_Unit * 2
1108 and then
1109 Size /= System_Storage_Unit * 4
1110 and then
1111 Size /= System_Storage_Unit * 8
1112 then
1113 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1114 Error_Msg_N
1115 ("size for primitive object must be a power of 2"
1116 & " and at least ^", N);
1117 end if;
1118 end if;
1119
1120 Set_Esize (U_Ent, Size);
1121 end if;
1122
1123 Set_Has_Size_Clause (U_Ent);
1124 end if;
1125 end Size;
1126
1127 -----------
1128 -- Small --
1129 -----------
1130
1131 -- Small attribute definition clause
1132
1133 when Attribute_Small => Small : declare
1134 Implicit_Base : constant Entity_Id := Base_Type (U_Ent);
1135 Small : Ureal;
1136
1137 begin
1138 Analyze_And_Resolve (Expr, Any_Real);
1139
1140 if Etype (Expr) = Any_Type then
1141 return;
1142
1143 elsif not Is_Static_Expression (Expr) then
1144 Flag_Non_Static_Expr
1145 ("small requires static expression!", Expr);
1146 return;
1147
1148 else
1149 Small := Expr_Value_R (Expr);
1150
1151 if Small <= Ureal_0 then
1152 Error_Msg_N ("small value must be greater than zero", Expr);
1153 return;
1154 end if;
1155
1156 end if;
1157
1158 if not Is_Ordinary_Fixed_Point_Type (U_Ent) then
1159 Error_Msg_N
1160 ("small requires an ordinary fixed point type", Nam);
1161
1162 elsif Has_Small_Clause (U_Ent) then
1163 Error_Msg_N ("small already given for &", Nam);
1164
1165 elsif Small > Delta_Value (U_Ent) then
1166 Error_Msg_N
1167 ("small value must not be greater then delta value", Nam);
1168
1169 else
1170 Set_Small_Value (U_Ent, Small);
1171 Set_Small_Value (Implicit_Base, Small);
1172 Set_Has_Small_Clause (U_Ent);
1173 Set_Has_Small_Clause (Implicit_Base);
1174 Set_Has_Non_Standard_Rep (Implicit_Base);
1175 end if;
1176 end Small;
1177
1178 ------------------
1179 -- Storage_Size --
1180 ------------------
1181
1182 -- Storage_Size attribute definition clause
1183
1184 when Attribute_Storage_Size => Storage_Size : declare
1185 Btype : constant Entity_Id := Base_Type (U_Ent);
1186 Sprag : Node_Id;
1187
1188 begin
1189 if Is_Task_Type (U_Ent) then
1190 if Warn_On_Obsolescent_Feature then
1191 Error_Msg_N
1192 ("storage size clause for task is an " &
1193 "obsolescent feature ('R'M 'J.9)?", N);
1194 Error_Msg_N
1195 ("|use Storage_Size pragma instead?", N);
1196 end if;
1197
1198 FOnly := True;
1199 end if;
1200
1201 if not Is_Access_Type (U_Ent)
1202 and then Ekind (U_Ent) /= E_Task_Type
1203 then
1204 Error_Msg_N ("storage size cannot be given for &", Nam);
1205
1206 elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then
1207 Error_Msg_N
1208 ("storage size cannot be given for a derived access type",
1209 Nam);
1210
1211 elsif Has_Storage_Size_Clause (Btype) then
1212 Error_Msg_N ("storage size already given for &", Nam);
1213
1214 else
1215 Analyze_And_Resolve (Expr, Any_Integer);
1216
1217 if Is_Access_Type (U_Ent) then
1218
1219 if Present (Associated_Storage_Pool (U_Ent)) then
1220 Error_Msg_N ("storage pool already given for &", Nam);
1221 return;
1222 end if;
1223
1224 if Compile_Time_Known_Value (Expr)
1225 and then Expr_Value (Expr) = 0
1226 then
1227 Set_No_Pool_Assigned (Btype);
1228 end if;
1229
1230 else -- Is_Task_Type (U_Ent)
1231 Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size);
1232
1233 if Present (Sprag) then
1234 Error_Msg_Sloc := Sloc (Sprag);
1235 Error_Msg_N
1236 ("Storage_Size already specified#", Nam);
1237 return;
1238 end if;
1239 end if;
1240
1241 Set_Has_Storage_Size_Clause (Btype);
1242 end if;
1243 end Storage_Size;
1244
1245 ------------------
1246 -- Storage_Pool --
1247 ------------------
1248
1249 -- Storage_Pool attribute definition clause
1250
1251 when Attribute_Storage_Pool => Storage_Pool : declare
1252 Pool : Entity_Id;
1253
1254 begin
1255 if Ekind (U_Ent) /= E_Access_Type
1256 and then Ekind (U_Ent) /= E_General_Access_Type
1257 then
1258 Error_Msg_N (
1259 "storage pool can only be given for access types", Nam);
1260 return;
1261
1262 elsif Is_Derived_Type (U_Ent) then
1263 Error_Msg_N
1264 ("storage pool cannot be given for a derived access type",
1265 Nam);
1266
1267 elsif Has_Storage_Size_Clause (U_Ent) then
1268 Error_Msg_N ("storage size already given for &", Nam);
1269 return;
1270
1271 elsif Present (Associated_Storage_Pool (U_Ent)) then
1272 Error_Msg_N ("storage pool already given for &", Nam);
1273 return;
1274 end if;
1275
1276 Analyze_And_Resolve
1277 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1278
1279 -- If the argument is a name that is not an entity name, then
1280 -- we construct a renaming operation to define an entity of
1281 -- type storage pool.
1282
1283 if not Is_Entity_Name (Expr)
1284 and then Is_Object_Reference (Expr)
1285 then
1286 Pool :=
1287 Make_Defining_Identifier (Loc,
1288 Chars => New_Internal_Name ('P'));
1289
1290 declare
1291 Rnode : constant Node_Id :=
1292 Make_Object_Renaming_Declaration (Loc,
1293 Defining_Identifier => Pool,
1294 Subtype_Mark =>
1295 New_Occurrence_Of (Etype (Expr), Loc),
1296 Name => Expr);
1297
1298 begin
1299 Insert_Before (N, Rnode);
1300 Analyze (Rnode);
1301 Set_Associated_Storage_Pool (U_Ent, Pool);
1302 end;
1303
1304 elsif Is_Entity_Name (Expr) then
1305 Pool := Entity (Expr);
1306
1307 -- If pool is a renamed object, get original one. This can
1308 -- happen with an explicit renaming, and within instances.
1309
1310 while Present (Renamed_Object (Pool))
1311 and then Is_Entity_Name (Renamed_Object (Pool))
1312 loop
1313 Pool := Entity (Renamed_Object (Pool));
1314 end loop;
1315
1316 if Present (Renamed_Object (Pool))
1317 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1318 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1319 then
1320 Pool := Entity (Expression (Renamed_Object (Pool)));
1321 end if;
1322
1323 if Present (Etype (Pool))
1324 and then Etype (Pool) /= RTE (RE_Stack_Bounded_Pool)
1325 and then Etype (Pool) /= RTE (RE_Unbounded_Reclaim_Pool)
1326 then
1327 Set_Associated_Storage_Pool (U_Ent, Pool);
1328 else
1329 Error_Msg_N ("Non sharable GNAT Pool", Expr);
1330 end if;
1331
1332 -- The pool may be specified as the Storage_Pool of some other
1333 -- type. It is rewritten as a class_wide conversion of the
1334 -- corresponding pool entity.
1335
1336 elsif Nkind (Expr) = N_Type_Conversion
1337 and then Is_Entity_Name (Expression (Expr))
1338 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1339 then
1340 Pool := Entity (Expression (Expr));
1341
1342 if Present (Etype (Pool))
1343 and then Etype (Pool) /= RTE (RE_Stack_Bounded_Pool)
1344 and then Etype (Pool) /= RTE (RE_Unbounded_Reclaim_Pool)
1345 then
1346 Set_Associated_Storage_Pool (U_Ent, Pool);
1347 else
1348 Error_Msg_N ("Non sharable GNAT Pool", Expr);
1349 end if;
1350
1351 else
1352 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1353 return;
1354 end if;
1355 end Storage_Pool;
1356
1357 ----------------
1358 -- Value_Size --
1359 ----------------
1360
1361 -- Value_Size attribute definition clause
1362
1363 when Attribute_Value_Size => Value_Size : declare
1364 Size : constant Uint := Static_Integer (Expr);
1365 Biased : Boolean;
1366
1367 begin
1368 if not Is_Type (U_Ent) then
1369 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1370
1371 elsif Present
1372 (Get_Attribute_Definition_Clause
1373 (U_Ent, Attribute_Value_Size))
1374 then
1375 Error_Msg_N ("Value_Size already given for &", Nam);
1376
1377 else
1378 if Is_Elementary_Type (U_Ent) then
1379 Check_Size (Expr, U_Ent, Size, Biased);
1380 Set_Has_Biased_Representation (U_Ent, Biased);
1381 end if;
1382
1383 Set_RM_Size (U_Ent, Size);
1384 end if;
1385 end Value_Size;
1386
1387 -----------
1388 -- Write --
1389 -----------
1390
1391 -- Write attribute definition clause
1392 -- check for class-wide case will be performed later
1393
1394 when Attribute_Write => Write : declare
1395 Subp : Entity_Id := Empty;
1396 I : Interp_Index;
1397 It : Interp;
1398 Pnam : Entity_Id;
1399
1400 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
1401 -- Return true if the entity is a procedure with an
1402 -- appropriate profile for the write attribute.
1403
1404 ----------------------
1405 -- Has_Good_Profile --
1406 ----------------------
1407
1408 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
1409 F : Entity_Id;
1410 Ok : Boolean := False;
1411
1412 begin
1413 if Ekind (Subp) = E_Procedure then
1414 F := First_Formal (Subp);
1415
1416 if Present (F) then
1417 if Ekind (Etype (F)) = E_Anonymous_Access_Type
1418 and then
1419 Designated_Type (Etype (F)) =
1420 Class_Wide_Type (RTE (RE_Root_Stream_Type))
1421 then
1422 Next_Formal (F);
1423 Ok := Present (F)
1424 and then Parameter_Mode (F) = E_In_Parameter
1425 and then Base_Type (Etype (F)) = Base_Type (Ent)
1426 and then No (Next_Formal (F));
1427 end if;
1428 end if;
1429 end if;
1430
1431 return Ok;
1432 end Has_Good_Profile;
1433
1434 -- Start of processing for Write attribute definition
1435
1436 begin
1437 FOnly := True;
1438
1439 if not Is_Type (U_Ent) then
1440 Error_Msg_N ("local name must be a subtype", Nam);
1441 return;
1442 end if;
1443
1444 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Write);
1445
1446 if Present (Pnam)
1447 and then Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
1448 = Base_Type (U_Ent)
1449 then
1450 Error_Msg_Sloc := Sloc (Pnam);
1451 Error_Msg_N ("write attribute already defined #", Nam);
1452 return;
1453 end if;
1454
1455 Analyze (Expr);
1456
1457 if Is_Entity_Name (Expr) then
1458 if not Is_Overloaded (Expr) then
1459 if Has_Good_Profile (Entity (Expr)) then
1460 Subp := Entity (Expr);
1461 end if;
1462
1463 else
1464 Get_First_Interp (Expr, I, It);
1465
1466 while Present (It.Nam) loop
1467 if Has_Good_Profile (It.Nam) then
1468 Subp := It.Nam;
1469 exit;
1470 end if;
1471
1472 Get_Next_Interp (I, It);
1473 end loop;
1474 end if;
1475 end if;
1476
1477 if Present (Subp) then
1478 Set_Entity (Expr, Subp);
1479 Set_Etype (Expr, Etype (Subp));
1480 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Write);
1481 else
1482 Error_Msg_N ("incorrect expression for write attribute", Expr);
1483 return;
1484 end if;
1485 end Write;
1486
1487 -- All other attributes cannot be set
1488
1489 when others =>
1490 Error_Msg_N
1491 ("attribute& cannot be set with definition clause", N);
1492
1493 end case;
1494
1495 -- The test for the type being frozen must be performed after
1496 -- any expression the clause has been analyzed since the expression
1497 -- itself might cause freezing that makes the clause illegal.
1498
1499 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1500 return;
1501 end if;
1502 end Analyze_Attribute_Definition_Clause;
1503
1504 ----------------------------
1505 -- Analyze_Code_Statement --
1506 ----------------------------
1507
1508 procedure Analyze_Code_Statement (N : Node_Id) is
1509 HSS : constant Node_Id := Parent (N);
1510 SBody : constant Node_Id := Parent (HSS);
1511 Subp : constant Entity_Id := Current_Scope;
1512 Stmt : Node_Id;
1513 Decl : Node_Id;
1514 StmtO : Node_Id;
1515 DeclO : Node_Id;
1516
1517 begin
1518 -- Analyze and check we get right type, note that this implements the
1519 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1520 -- is the only way that Asm_Insn could possibly be visible.
1521
1522 Analyze_And_Resolve (Expression (N));
1523
1524 if Etype (Expression (N)) = Any_Type then
1525 return;
1526 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1527 Error_Msg_N ("incorrect type for code statement", N);
1528 return;
1529 end if;
1530
1531 -- Make sure we appear in the handled statement sequence of a
1532 -- subprogram (RM 13.8(3)).
1533
1534 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1535 or else Nkind (SBody) /= N_Subprogram_Body
1536 then
1537 Error_Msg_N
1538 ("code statement can only appear in body of subprogram", N);
1539 return;
1540 end if;
1541
1542 -- Do remaining checks (RM 13.8(3)) if not already done
1543
1544 if not Is_Machine_Code_Subprogram (Subp) then
1545 Set_Is_Machine_Code_Subprogram (Subp);
1546
1547 -- No exception handlers allowed
1548
1549 if Present (Exception_Handlers (HSS)) then
1550 Error_Msg_N
1551 ("exception handlers not permitted in machine code subprogram",
1552 First (Exception_Handlers (HSS)));
1553 end if;
1554
1555 -- No declarations other than use clauses and pragmas (we allow
1556 -- certain internally generated declarations as well).
1557
1558 Decl := First (Declarations (SBody));
1559 while Present (Decl) loop
1560 DeclO := Original_Node (Decl);
1561 if Comes_From_Source (DeclO)
1562 and then Nkind (DeclO) /= N_Pragma
1563 and then Nkind (DeclO) /= N_Use_Package_Clause
1564 and then Nkind (DeclO) /= N_Use_Type_Clause
1565 and then Nkind (DeclO) /= N_Implicit_Label_Declaration
1566 then
1567 Error_Msg_N
1568 ("this declaration not allowed in machine code subprogram",
1569 DeclO);
1570 end if;
1571
1572 Next (Decl);
1573 end loop;
1574
1575 -- No statements other than code statements, pragmas, and labels.
1576 -- Again we allow certain internally generated statements.
1577
1578 Stmt := First (Statements (HSS));
1579 while Present (Stmt) loop
1580 StmtO := Original_Node (Stmt);
1581 if Comes_From_Source (StmtO)
1582 and then Nkind (StmtO) /= N_Pragma
1583 and then Nkind (StmtO) /= N_Label
1584 and then Nkind (StmtO) /= N_Code_Statement
1585 then
1586 Error_Msg_N
1587 ("this statement is not allowed in machine code subprogram",
1588 StmtO);
1589 end if;
1590
1591 Next (Stmt);
1592 end loop;
1593 end if;
1594 end Analyze_Code_Statement;
1595
1596 -----------------------------------------------
1597 -- Analyze_Enumeration_Representation_Clause --
1598 -----------------------------------------------
1599
1600 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1601 Ident : constant Node_Id := Identifier (N);
1602 Aggr : constant Node_Id := Array_Aggregate (N);
1603 Enumtype : Entity_Id;
1604 Elit : Entity_Id;
1605 Expr : Node_Id;
1606 Assoc : Node_Id;
1607 Choice : Node_Id;
1608 Val : Uint;
1609 Err : Boolean := False;
1610
1611 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1612 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1613 Min : Uint;
1614 Max : Uint;
1615
1616 begin
1617 -- First some basic error checks
1618
1619 Find_Type (Ident);
1620 Enumtype := Entity (Ident);
1621
1622 if Enumtype = Any_Type
1623 or else Rep_Item_Too_Early (Enumtype, N)
1624 then
1625 return;
1626 else
1627 Enumtype := Underlying_Type (Enumtype);
1628 end if;
1629
1630 if not Is_Enumeration_Type (Enumtype) then
1631 Error_Msg_NE
1632 ("enumeration type required, found}",
1633 Ident, First_Subtype (Enumtype));
1634 return;
1635 end if;
1636
1637 -- Ignore rep clause on generic actual type. This will already have
1638 -- been flagged on the template as an error, and this is the safest
1639 -- way to ensure we don't get a junk cascaded message in the instance.
1640
1641 if Is_Generic_Actual_Type (Enumtype) then
1642 return;
1643
1644 -- Type must be in current scope
1645
1646 elsif Scope (Enumtype) /= Current_Scope then
1647 Error_Msg_N ("type must be declared in this scope", Ident);
1648 return;
1649
1650 -- Type must be a first subtype
1651
1652 elsif not Is_First_Subtype (Enumtype) then
1653 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1654 return;
1655
1656 -- Ignore duplicate rep clause
1657
1658 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1659 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1660 return;
1661
1662 -- Don't allow rep clause if root type is standard [wide_]character
1663
1664 elsif Root_Type (Enumtype) = Standard_Character
1665 or else Root_Type (Enumtype) = Standard_Wide_Character
1666 then
1667 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1668 return;
1669
1670 -- All tests passed, so set rep clause in place
1671
1672 else
1673 Set_Has_Enumeration_Rep_Clause (Enumtype);
1674 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
1675 end if;
1676
1677 -- Now we process the aggregate. Note that we don't use the normal
1678 -- aggregate code for this purpose, because we don't want any of the
1679 -- normal expansion activities, and a number of special semantic
1680 -- rules apply (including the component type being any integer type)
1681
1682 -- Badent signals that we found some incorrect entries processing
1683 -- the list. The final checks for completeness and ordering are
1684 -- skipped in this case.
1685
1686 Elit := First_Literal (Enumtype);
1687
1688 -- First the positional entries if any
1689
1690 if Present (Expressions (Aggr)) then
1691 Expr := First (Expressions (Aggr));
1692 while Present (Expr) loop
1693 if No (Elit) then
1694 Error_Msg_N ("too many entries in aggregate", Expr);
1695 return;
1696 end if;
1697
1698 Val := Static_Integer (Expr);
1699
1700 if Val = No_Uint then
1701 Err := True;
1702
1703 elsif Val < Lo or else Hi < Val then
1704 Error_Msg_N ("value outside permitted range", Expr);
1705 Err := True;
1706 end if;
1707
1708 Set_Enumeration_Rep (Elit, Val);
1709 Set_Enumeration_Rep_Expr (Elit, Expr);
1710 Next (Expr);
1711 Next (Elit);
1712 end loop;
1713 end if;
1714
1715 -- Now process the named entries if present
1716
1717 if Present (Component_Associations (Aggr)) then
1718 Assoc := First (Component_Associations (Aggr));
1719 while Present (Assoc) loop
1720 Choice := First (Choices (Assoc));
1721
1722 if Present (Next (Choice)) then
1723 Error_Msg_N
1724 ("multiple choice not allowed here", Next (Choice));
1725 Err := True;
1726 end if;
1727
1728 if Nkind (Choice) = N_Others_Choice then
1729 Error_Msg_N ("others choice not allowed here", Choice);
1730 Err := True;
1731
1732 elsif Nkind (Choice) = N_Range then
1733 -- ??? should allow zero/one element range here
1734 Error_Msg_N ("range not allowed here", Choice);
1735 Err := True;
1736
1737 else
1738 Analyze_And_Resolve (Choice, Enumtype);
1739
1740 if Is_Entity_Name (Choice)
1741 and then Is_Type (Entity (Choice))
1742 then
1743 Error_Msg_N ("subtype name not allowed here", Choice);
1744 Err := True;
1745 -- ??? should allow static subtype with zero/one entry
1746
1747 elsif Etype (Choice) = Base_Type (Enumtype) then
1748 if not Is_Static_Expression (Choice) then
1749 Flag_Non_Static_Expr
1750 ("non-static expression used for choice!", Choice);
1751 Err := True;
1752
1753 else
1754 Elit := Expr_Value_E (Choice);
1755
1756 if Present (Enumeration_Rep_Expr (Elit)) then
1757 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
1758 Error_Msg_NE
1759 ("representation for& previously given#",
1760 Choice, Elit);
1761 Err := True;
1762 end if;
1763
1764 Set_Enumeration_Rep_Expr (Elit, Choice);
1765
1766 Expr := Expression (Assoc);
1767 Val := Static_Integer (Expr);
1768
1769 if Val = No_Uint then
1770 Err := True;
1771
1772 elsif Val < Lo or else Hi < Val then
1773 Error_Msg_N ("value outside permitted range", Expr);
1774 Err := True;
1775 end if;
1776
1777 Set_Enumeration_Rep (Elit, Val);
1778 end if;
1779 end if;
1780 end if;
1781
1782 Next (Assoc);
1783 end loop;
1784 end if;
1785
1786 -- Aggregate is fully processed. Now we check that a full set of
1787 -- representations was given, and that they are in range and in order.
1788 -- These checks are only done if no other errors occurred.
1789
1790 if not Err then
1791 Min := No_Uint;
1792 Max := No_Uint;
1793
1794 Elit := First_Literal (Enumtype);
1795 while Present (Elit) loop
1796 if No (Enumeration_Rep_Expr (Elit)) then
1797 Error_Msg_NE ("missing representation for&!", N, Elit);
1798
1799 else
1800 Val := Enumeration_Rep (Elit);
1801
1802 if Min = No_Uint then
1803 Min := Val;
1804 end if;
1805
1806 if Val /= No_Uint then
1807 if Max /= No_Uint and then Val <= Max then
1808 Error_Msg_NE
1809 ("enumeration value for& not ordered!",
1810 Enumeration_Rep_Expr (Elit), Elit);
1811 end if;
1812
1813 Max := Val;
1814 end if;
1815
1816 -- If there is at least one literal whose representation
1817 -- is not equal to the Pos value, then note that this
1818 -- enumeration type has a non-standard representation.
1819
1820 if Val /= Enumeration_Pos (Elit) then
1821 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
1822 end if;
1823 end if;
1824
1825 Next (Elit);
1826 end loop;
1827
1828 -- Now set proper size information
1829
1830 declare
1831 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
1832
1833 begin
1834 if Has_Size_Clause (Enumtype) then
1835 if Esize (Enumtype) >= Minsize then
1836 null;
1837
1838 else
1839 Minsize :=
1840 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
1841
1842 if Esize (Enumtype) < Minsize then
1843 Error_Msg_N ("previously given size is too small", N);
1844
1845 else
1846 Set_Has_Biased_Representation (Enumtype);
1847 end if;
1848 end if;
1849
1850 else
1851 Set_RM_Size (Enumtype, Minsize);
1852 Set_Enum_Esize (Enumtype);
1853 end if;
1854
1855 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
1856 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
1857 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
1858 end;
1859 end if;
1860
1861 -- We repeat the too late test in case it froze itself!
1862
1863 if Rep_Item_Too_Late (Enumtype, N) then
1864 null;
1865 end if;
1866 end Analyze_Enumeration_Representation_Clause;
1867
1868 ----------------------------
1869 -- Analyze_Free_Statement --
1870 ----------------------------
1871
1872 procedure Analyze_Free_Statement (N : Node_Id) is
1873 begin
1874 Analyze (Expression (N));
1875 end Analyze_Free_Statement;
1876
1877 ------------------------------------------
1878 -- Analyze_Record_Representation_Clause --
1879 ------------------------------------------
1880
1881 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
1882 Loc : constant Source_Ptr := Sloc (N);
1883 Ident : constant Node_Id := Identifier (N);
1884 Rectype : Entity_Id;
1885 Fent : Entity_Id;
1886 CC : Node_Id;
1887 Posit : Uint;
1888 Fbit : Uint;
1889 Lbit : Uint;
1890 Hbit : Uint := Uint_0;
1891 Comp : Entity_Id;
1892 Ocomp : Entity_Id;
1893 Biased : Boolean;
1894
1895 Max_Bit_So_Far : Uint;
1896 -- Records the maximum bit position so far. If all field positions
1897 -- are monotonically increasing, then we can skip the circuit for
1898 -- checking for overlap, since no overlap is possible.
1899
1900 Overlap_Check_Required : Boolean;
1901 -- Used to keep track of whether or not an overlap check is required
1902
1903 Ccount : Natural := 0;
1904 -- Number of component clauses in record rep clause
1905
1906 begin
1907 Find_Type (Ident);
1908 Rectype := Entity (Ident);
1909
1910 if Rectype = Any_Type
1911 or else Rep_Item_Too_Early (Rectype, N)
1912 then
1913 return;
1914 else
1915 Rectype := Underlying_Type (Rectype);
1916 end if;
1917
1918 -- First some basic error checks
1919
1920 if not Is_Record_Type (Rectype) then
1921 Error_Msg_NE
1922 ("record type required, found}", Ident, First_Subtype (Rectype));
1923 return;
1924
1925 elsif Is_Unchecked_Union (Rectype) then
1926 Error_Msg_N
1927 ("record rep clause not allowed for Unchecked_Union", N);
1928
1929 elsif Scope (Rectype) /= Current_Scope then
1930 Error_Msg_N ("type must be declared in this scope", N);
1931 return;
1932
1933 elsif not Is_First_Subtype (Rectype) then
1934 Error_Msg_N ("cannot give record rep clause for subtype", N);
1935 return;
1936
1937 elsif Has_Record_Rep_Clause (Rectype) then
1938 Error_Msg_N ("duplicate record rep clause ignored", N);
1939 return;
1940
1941 elsif Rep_Item_Too_Late (Rectype, N) then
1942 return;
1943 end if;
1944
1945 if Present (Mod_Clause (N)) then
1946 declare
1947 Loc : constant Source_Ptr := Sloc (N);
1948 M : constant Node_Id := Mod_Clause (N);
1949 P : constant List_Id := Pragmas_Before (M);
1950 AtM_Nod : Node_Id;
1951
1952 Mod_Val : Uint;
1953 pragma Warnings (Off, Mod_Val);
1954
1955 begin
1956 if Warn_On_Obsolescent_Feature then
1957 Error_Msg_N
1958 ("mod clause is an obsolescent feature ('R'M 'J.8)?", N);
1959 Error_Msg_N
1960 ("|use alignment attribute definition clause instead?", N);
1961 end if;
1962
1963 if Present (P) then
1964 Analyze_List (P);
1965 end if;
1966
1967 -- In ASIS_Mode mode, expansion is disabled, but we must
1968 -- convert the Mod clause into an alignment clause anyway, so
1969 -- that the back-end can compute and back-annotate properly the
1970 -- size and alignment of types that may include this record.
1971
1972 if Operating_Mode = Check_Semantics
1973 and then ASIS_Mode
1974 then
1975 AtM_Nod :=
1976 Make_Attribute_Definition_Clause (Loc,
1977 Name => New_Reference_To (Base_Type (Rectype), Loc),
1978 Chars => Name_Alignment,
1979 Expression => Relocate_Node (Expression (M)));
1980
1981 Set_From_At_Mod (AtM_Nod);
1982 Insert_After (N, AtM_Nod);
1983 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
1984 Set_Mod_Clause (N, Empty);
1985
1986 else
1987 -- Get the alignment value to perform error checking
1988
1989 Mod_Val := Get_Alignment_Value (Expression (M));
1990
1991 end if;
1992 end;
1993 end if;
1994
1995 -- Clear any existing component clauses for the type (this happens
1996 -- with derived types, where we are now overriding the original)
1997
1998 Fent := First_Entity (Rectype);
1999
2000 Comp := Fent;
2001 while Present (Comp) loop
2002 if Ekind (Comp) = E_Component
2003 or else Ekind (Comp) = E_Discriminant
2004 then
2005 Set_Component_Clause (Comp, Empty);
2006 end if;
2007
2008 Next_Entity (Comp);
2009 end loop;
2010
2011 -- All done if no component clauses
2012
2013 CC := First (Component_Clauses (N));
2014
2015 if No (CC) then
2016 return;
2017 end if;
2018
2019 -- If a tag is present, then create a component clause that places
2020 -- it at the start of the record (otherwise gigi may place it after
2021 -- other fields that have rep clauses).
2022
2023 if Nkind (Fent) = N_Defining_Identifier
2024 and then Chars (Fent) = Name_uTag
2025 then
2026 Set_Component_Bit_Offset (Fent, Uint_0);
2027 Set_Normalized_Position (Fent, Uint_0);
2028 Set_Normalized_First_Bit (Fent, Uint_0);
2029 Set_Normalized_Position_Max (Fent, Uint_0);
2030 Init_Esize (Fent, System_Address_Size);
2031
2032 Set_Component_Clause (Fent,
2033 Make_Component_Clause (Loc,
2034 Component_Name =>
2035 Make_Identifier (Loc,
2036 Chars => Name_uTag),
2037
2038 Position =>
2039 Make_Integer_Literal (Loc,
2040 Intval => Uint_0),
2041
2042 First_Bit =>
2043 Make_Integer_Literal (Loc,
2044 Intval => Uint_0),
2045
2046 Last_Bit =>
2047 Make_Integer_Literal (Loc,
2048 UI_From_Int (System_Address_Size))));
2049
2050 Ccount := Ccount + 1;
2051 end if;
2052
2053 -- A representation like this applies to the base type
2054
2055 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2056 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2057 Set_Has_Specified_Layout (Base_Type (Rectype));
2058
2059 Max_Bit_So_Far := Uint_Minus_1;
2060 Overlap_Check_Required := False;
2061
2062 -- Process the component clauses
2063
2064 while Present (CC) loop
2065
2066 -- If pragma, just analyze it
2067
2068 if Nkind (CC) = N_Pragma then
2069 Analyze (CC);
2070
2071 -- Processing for real component clause
2072
2073 else
2074 Ccount := Ccount + 1;
2075 Posit := Static_Integer (Position (CC));
2076 Fbit := Static_Integer (First_Bit (CC));
2077 Lbit := Static_Integer (Last_Bit (CC));
2078
2079 if Posit /= No_Uint
2080 and then Fbit /= No_Uint
2081 and then Lbit /= No_Uint
2082 then
2083 if Posit < 0 then
2084 Error_Msg_N
2085 ("position cannot be negative", Position (CC));
2086
2087 elsif Fbit < 0 then
2088 Error_Msg_N
2089 ("first bit cannot be negative", First_Bit (CC));
2090
2091 -- Values look OK, so find the corresponding record component
2092 -- Even though the syntax allows an attribute reference for
2093 -- implementation-defined components, GNAT does not allow the
2094 -- tag to get an explicit position.
2095
2096 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2097 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2098 Error_Msg_N ("position of tag cannot be specified", CC);
2099 else
2100 Error_Msg_N ("illegal component name", CC);
2101 end if;
2102
2103 else
2104 Comp := First_Entity (Rectype);
2105 while Present (Comp) loop
2106 exit when Chars (Comp) = Chars (Component_Name (CC));
2107 Next_Entity (Comp);
2108 end loop;
2109
2110 if No (Comp) then
2111
2112 -- Maybe component of base type that is absent from
2113 -- statically constrained first subtype.
2114
2115 Comp := First_Entity (Base_Type (Rectype));
2116 while Present (Comp) loop
2117 exit when Chars (Comp) = Chars (Component_Name (CC));
2118 Next_Entity (Comp);
2119 end loop;
2120 end if;
2121
2122 if No (Comp) then
2123 Error_Msg_N
2124 ("component clause is for non-existent field", CC);
2125
2126 elsif Present (Component_Clause (Comp)) then
2127 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2128 Error_Msg_N
2129 ("component clause previously given#", CC);
2130
2131 else
2132 -- Update Fbit and Lbit to the actual bit number.
2133
2134 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2135 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2136
2137 if Fbit <= Max_Bit_So_Far then
2138 Overlap_Check_Required := True;
2139 else
2140 Max_Bit_So_Far := Lbit;
2141 end if;
2142
2143 if Has_Size_Clause (Rectype)
2144 and then Esize (Rectype) <= Lbit
2145 then
2146 Error_Msg_N
2147 ("bit number out of range of specified size",
2148 Last_Bit (CC));
2149 else
2150 Set_Component_Clause (Comp, CC);
2151 Set_Component_Bit_Offset (Comp, Fbit);
2152 Set_Esize (Comp, 1 + (Lbit - Fbit));
2153 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2154 Set_Normalized_Position (Comp, Fbit / SSU);
2155
2156 Set_Normalized_Position_Max
2157 (Fent, Normalized_Position (Fent));
2158
2159 if Is_Tagged_Type (Rectype)
2160 and then Fbit < System_Address_Size
2161 then
2162 Error_Msg_NE
2163 ("component overlaps tag field of&",
2164 CC, Rectype);
2165 end if;
2166
2167 -- This information is also set in the corresponding
2168 -- component of the base type, found by accessing the
2169 -- Original_Record_Component link if it is present.
2170
2171 Ocomp := Original_Record_Component (Comp);
2172
2173 if Hbit < Lbit then
2174 Hbit := Lbit;
2175 end if;
2176
2177 Check_Size
2178 (Component_Name (CC),
2179 Etype (Comp),
2180 Esize (Comp),
2181 Biased);
2182
2183 Set_Has_Biased_Representation (Comp, Biased);
2184
2185 if Present (Ocomp) then
2186 Set_Component_Clause (Ocomp, CC);
2187 Set_Component_Bit_Offset (Ocomp, Fbit);
2188 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2189 Set_Normalized_Position (Ocomp, Fbit / SSU);
2190 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2191
2192 Set_Normalized_Position_Max
2193 (Ocomp, Normalized_Position (Ocomp));
2194
2195 Set_Has_Biased_Representation
2196 (Ocomp, Has_Biased_Representation (Comp));
2197 end if;
2198
2199 if Esize (Comp) < 0 then
2200 Error_Msg_N ("component size is negative", CC);
2201 end if;
2202 end if;
2203 end if;
2204 end if;
2205 end if;
2206 end if;
2207
2208 Next (CC);
2209 end loop;
2210
2211 -- Now that we have processed all the component clauses, check for
2212 -- overlap. We have to leave this till last, since the components
2213 -- can appear in any arbitrary order in the representation clause.
2214
2215 -- We do not need this check if all specified ranges were monotonic,
2216 -- as recorded by Overlap_Check_Required being False at this stage.
2217
2218 -- This first section checks if there are any overlapping entries
2219 -- at all. It does this by sorting all entries and then seeing if
2220 -- there are any overlaps. If there are none, then that is decisive,
2221 -- but if there are overlaps, they may still be OK (they may result
2222 -- from fields in different variants).
2223
2224 if Overlap_Check_Required then
2225 Overlap_Check1 : declare
2226
2227 OC_Fbit : array (0 .. Ccount) of Uint;
2228 -- First-bit values for component clauses, the value is the
2229 -- offset of the first bit of the field from start of record.
2230 -- The zero entry is for use in sorting.
2231
2232 OC_Lbit : array (0 .. Ccount) of Uint;
2233 -- Last-bit values for component clauses, the value is the
2234 -- offset of the last bit of the field from start of record.
2235 -- The zero entry is for use in sorting.
2236
2237 OC_Count : Natural := 0;
2238 -- Count of entries in OC_Fbit and OC_Lbit
2239
2240 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2241 -- Compare routine for Sort (See GNAT.Heap_Sort_A)
2242
2243 procedure OC_Move (From : Natural; To : Natural);
2244 -- Move routine for Sort (see GNAT.Heap_Sort_A)
2245
2246 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2247 begin
2248 return OC_Fbit (Op1) < OC_Fbit (Op2);
2249 end OC_Lt;
2250
2251 procedure OC_Move (From : Natural; To : Natural) is
2252 begin
2253 OC_Fbit (To) := OC_Fbit (From);
2254 OC_Lbit (To) := OC_Lbit (From);
2255 end OC_Move;
2256
2257 begin
2258 CC := First (Component_Clauses (N));
2259 while Present (CC) loop
2260 if Nkind (CC) /= N_Pragma then
2261 Posit := Static_Integer (Position (CC));
2262 Fbit := Static_Integer (First_Bit (CC));
2263 Lbit := Static_Integer (Last_Bit (CC));
2264
2265 if Posit /= No_Uint
2266 and then Fbit /= No_Uint
2267 and then Lbit /= No_Uint
2268 then
2269 OC_Count := OC_Count + 1;
2270 Posit := Posit * SSU;
2271 OC_Fbit (OC_Count) := Fbit + Posit;
2272 OC_Lbit (OC_Count) := Lbit + Posit;
2273 end if;
2274 end if;
2275
2276 Next (CC);
2277 end loop;
2278
2279 Sort
2280 (OC_Count,
2281 OC_Move'Unrestricted_Access,
2282 OC_Lt'Unrestricted_Access);
2283
2284 Overlap_Check_Required := False;
2285 for J in 1 .. OC_Count - 1 loop
2286 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2287 Overlap_Check_Required := True;
2288 exit;
2289 end if;
2290 end loop;
2291 end Overlap_Check1;
2292 end if;
2293
2294 -- If Overlap_Check_Required is still True, then we have to do
2295 -- the full scale overlap check, since we have at least two fields
2296 -- that do overlap, and we need to know if that is OK since they
2297 -- are in the same variant, or whether we have a definite problem
2298
2299 if Overlap_Check_Required then
2300 Overlap_Check2 : declare
2301 C1_Ent, C2_Ent : Entity_Id;
2302 -- Entities of components being checked for overlap
2303
2304 Clist : Node_Id;
2305 -- Component_List node whose Component_Items are being checked
2306
2307 Citem : Node_Id;
2308 -- Component declaration for component being checked
2309
2310 begin
2311 C1_Ent := First_Entity (Base_Type (Rectype));
2312
2313 -- Loop through all components in record. For each component check
2314 -- for overlap with any of the preceding elements on the component
2315 -- list containing the component, and also, if the component is in
2316 -- a variant, check against components outside the case structure.
2317 -- This latter test is repeated recursively up the variant tree.
2318
2319 Main_Component_Loop : while Present (C1_Ent) loop
2320 if Ekind (C1_Ent) /= E_Component
2321 and then Ekind (C1_Ent) /= E_Discriminant
2322 then
2323 goto Continue_Main_Component_Loop;
2324 end if;
2325
2326 -- Skip overlap check if entity has no declaration node. This
2327 -- happens with discriminants in constrained derived types.
2328 -- Probably we are missing some checks as a result, but that
2329 -- does not seem terribly serious ???
2330
2331 if No (Declaration_Node (C1_Ent)) then
2332 goto Continue_Main_Component_Loop;
2333 end if;
2334
2335 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2336
2337 -- Loop through component lists that need checking. Check the
2338 -- current component list and all lists in variants above us.
2339
2340 Component_List_Loop : loop
2341
2342 -- If derived type definition, go to full declaration
2343 -- If at outer level, check discriminants if there are any
2344
2345 if Nkind (Clist) = N_Derived_Type_Definition then
2346 Clist := Parent (Clist);
2347 end if;
2348
2349 -- Outer level of record definition, check discriminants
2350
2351 if Nkind (Clist) = N_Full_Type_Declaration
2352 or else Nkind (Clist) = N_Private_Type_Declaration
2353 then
2354 if Has_Discriminants (Defining_Identifier (Clist)) then
2355 C2_Ent :=
2356 First_Discriminant (Defining_Identifier (Clist));
2357
2358 while Present (C2_Ent) loop
2359 exit when C1_Ent = C2_Ent;
2360 Check_Component_Overlap (C1_Ent, C2_Ent);
2361 Next_Discriminant (C2_Ent);
2362 end loop;
2363 end if;
2364
2365 -- Record extension case
2366
2367 elsif Nkind (Clist) = N_Derived_Type_Definition then
2368 Clist := Empty;
2369
2370 -- Otherwise check one component list
2371
2372 else
2373 Citem := First (Component_Items (Clist));
2374
2375 while Present (Citem) loop
2376 if Nkind (Citem) = N_Component_Declaration then
2377 C2_Ent := Defining_Identifier (Citem);
2378 exit when C1_Ent = C2_Ent;
2379 Check_Component_Overlap (C1_Ent, C2_Ent);
2380 end if;
2381
2382 Next (Citem);
2383 end loop;
2384 end if;
2385
2386 -- Check for variants above us (the parent of the Clist can
2387 -- be a variant, in which case its parent is a variant part,
2388 -- and the parent of the variant part is a component list
2389 -- whose components must all be checked against the current
2390 -- component for overlap.
2391
2392 if Nkind (Parent (Clist)) = N_Variant then
2393 Clist := Parent (Parent (Parent (Clist)));
2394
2395 -- Check for possible discriminant part in record, this is
2396 -- treated essentially as another level in the recursion.
2397 -- For this case we have the parent of the component list
2398 -- is the record definition, and its parent is the full
2399 -- type declaration which contains the discriminant
2400 -- specifications.
2401
2402 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2403 Clist := Parent (Parent ((Clist)));
2404
2405 -- If neither of these two cases, we are at the top of
2406 -- the tree
2407
2408 else
2409 exit Component_List_Loop;
2410 end if;
2411 end loop Component_List_Loop;
2412
2413 <<Continue_Main_Component_Loop>>
2414 Next_Entity (C1_Ent);
2415
2416 end loop Main_Component_Loop;
2417 end Overlap_Check2;
2418 end if;
2419
2420 -- For records that have component clauses for all components, and
2421 -- whose size is less than or equal to 32, we need to know the size
2422 -- in the front end to activate possible packed array processing
2423 -- where the component type is a record.
2424
2425 -- At this stage Hbit + 1 represents the first unused bit from all
2426 -- the component clauses processed, so if the component clauses are
2427 -- complete, then this is the length of the record.
2428
2429 -- For records longer than System.Storage_Unit, and for those where
2430 -- not all components have component clauses, the back end determines
2431 -- the length (it may for example be appopriate to round up the size
2432 -- to some convenient boundary, based on alignment considerations etc).
2433
2434 if Unknown_RM_Size (Rectype)
2435 and then Hbit + 1 <= 32
2436 then
2437 -- Nothing to do if at least one component with no component clause
2438
2439 Comp := First_Entity (Rectype);
2440 while Present (Comp) loop
2441 if Ekind (Comp) = E_Component
2442 or else Ekind (Comp) = E_Discriminant
2443 then
2444 if No (Component_Clause (Comp)) then
2445 return;
2446 end if;
2447 end if;
2448
2449 Next_Entity (Comp);
2450 end loop;
2451
2452 -- If we fall out of loop, all components have component clauses
2453 -- and so we can set the size to the maximum value.
2454
2455 Set_RM_Size (Rectype, Hbit + 1);
2456 end if;
2457 end Analyze_Record_Representation_Clause;
2458
2459 -----------------------------
2460 -- Check_Component_Overlap --
2461 -----------------------------
2462
2463 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
2464 begin
2465 if Present (Component_Clause (C1_Ent))
2466 and then Present (Component_Clause (C2_Ent))
2467 then
2468 -- Exclude odd case where we have two tag fields in the same
2469 -- record, both at location zero. This seems a bit strange,
2470 -- but it seems to happen in some circumstances ???
2471
2472 if Chars (C1_Ent) = Name_uTag
2473 and then Chars (C2_Ent) = Name_uTag
2474 then
2475 return;
2476 end if;
2477
2478 -- Here we check if the two fields overlap
2479
2480 declare
2481 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
2482 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
2483 E1 : constant Uint := S1 + Esize (C1_Ent);
2484 E2 : constant Uint := S2 + Esize (C2_Ent);
2485
2486 begin
2487 if E2 <= S1 or else E1 <= S2 then
2488 null;
2489 else
2490 Error_Msg_Node_2 :=
2491 Component_Name (Component_Clause (C2_Ent));
2492 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
2493 Error_Msg_Node_1 :=
2494 Component_Name (Component_Clause (C1_Ent));
2495 Error_Msg_N
2496 ("component& overlaps & #",
2497 Component_Name (Component_Clause (C1_Ent)));
2498 end if;
2499 end;
2500 end if;
2501 end Check_Component_Overlap;
2502
2503 -----------------------------------
2504 -- Check_Constant_Address_Clause --
2505 -----------------------------------
2506
2507 procedure Check_Constant_Address_Clause
2508 (Expr : Node_Id;
2509 U_Ent : Entity_Id)
2510 is
2511 procedure Check_At_Constant_Address (Nod : Node_Id);
2512 -- Checks that the given node N represents a name whose 'Address
2513 -- is constant (in the same sense as OK_Constant_Address_Clause,
2514 -- i.e. the address value is the same at the point of declaration
2515 -- of U_Ent and at the time of elaboration of the address clause.
2516
2517 procedure Check_Expr_Constants (Nod : Node_Id);
2518 -- Checks that Nod meets the requirements for a constant address
2519 -- clause in the sense of the enclosing procedure.
2520
2521 procedure Check_List_Constants (Lst : List_Id);
2522 -- Check that all elements of list Lst meet the requirements for a
2523 -- constant address clause in the sense of the enclosing procedure.
2524
2525 -------------------------------
2526 -- Check_At_Constant_Address --
2527 -------------------------------
2528
2529 procedure Check_At_Constant_Address (Nod : Node_Id) is
2530 begin
2531 if Is_Entity_Name (Nod) then
2532 if Present (Address_Clause (Entity ((Nod)))) then
2533 Error_Msg_NE
2534 ("invalid address clause for initialized object &!",
2535 Nod, U_Ent);
2536 Error_Msg_NE
2537 ("address for& cannot" &
2538 " depend on another address clause! ('R'M 13.1(22))!",
2539 Nod, U_Ent);
2540
2541 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
2542 and then Sloc (U_Ent) < Sloc (Entity (Nod))
2543 then
2544 Error_Msg_NE
2545 ("invalid address clause for initialized object &!",
2546 Nod, U_Ent);
2547 Error_Msg_Name_1 := Chars (Entity (Nod));
2548 Error_Msg_Name_2 := Chars (U_Ent);
2549 Error_Msg_N
2550 ("\% must be defined before % ('R'M 13.1(22))!",
2551 Nod);
2552 end if;
2553
2554 elsif Nkind (Nod) = N_Selected_Component then
2555 declare
2556 T : constant Entity_Id := Etype (Prefix (Nod));
2557
2558 begin
2559 if (Is_Record_Type (T)
2560 and then Has_Discriminants (T))
2561 or else
2562 (Is_Access_Type (T)
2563 and then Is_Record_Type (Designated_Type (T))
2564 and then Has_Discriminants (Designated_Type (T)))
2565 then
2566 Error_Msg_NE
2567 ("invalid address clause for initialized object &!",
2568 Nod, U_Ent);
2569 Error_Msg_N
2570 ("\address cannot depend on component" &
2571 " of discriminated record ('R'M 13.1(22))!",
2572 Nod);
2573 else
2574 Check_At_Constant_Address (Prefix (Nod));
2575 end if;
2576 end;
2577
2578 elsif Nkind (Nod) = N_Indexed_Component then
2579 Check_At_Constant_Address (Prefix (Nod));
2580 Check_List_Constants (Expressions (Nod));
2581
2582 else
2583 Check_Expr_Constants (Nod);
2584 end if;
2585 end Check_At_Constant_Address;
2586
2587 --------------------------
2588 -- Check_Expr_Constants --
2589 --------------------------
2590
2591 procedure Check_Expr_Constants (Nod : Node_Id) is
2592 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
2593 Ent : Entity_Id := Empty;
2594
2595 begin
2596 if Nkind (Nod) in N_Has_Etype
2597 and then Etype (Nod) = Any_Type
2598 then
2599 return;
2600 end if;
2601
2602 case Nkind (Nod) is
2603 when N_Empty | N_Error =>
2604 return;
2605
2606 when N_Identifier | N_Expanded_Name =>
2607 Ent := Entity (Nod);
2608
2609 -- We need to look at the original node if it is different
2610 -- from the node, since we may have rewritten things and
2611 -- substituted an identifier representing the rewrite.
2612
2613 if Original_Node (Nod) /= Nod then
2614 Check_Expr_Constants (Original_Node (Nod));
2615
2616 -- If the node is an object declaration without initial
2617 -- value, some code has been expanded, and the expression
2618 -- is not constant, even if the constituents might be
2619 -- acceptable, as in A'Address + offset.
2620
2621 if Ekind (Ent) = E_Variable
2622 and then Nkind (Declaration_Node (Ent))
2623 = N_Object_Declaration
2624 and then
2625 No (Expression (Declaration_Node (Ent)))
2626 then
2627 Error_Msg_NE
2628 ("invalid address clause for initialized object &!",
2629 Nod, U_Ent);
2630
2631 -- If entity is constant, it may be the result of expanding
2632 -- a check. We must verify that its declaration appears
2633 -- before the object in question, else we also reject the
2634 -- address clause.
2635
2636 elsif Ekind (Ent) = E_Constant
2637 and then In_Same_Source_Unit (Ent, U_Ent)
2638 and then Sloc (Ent) > Loc_U_Ent
2639 then
2640 Error_Msg_NE
2641 ("invalid address clause for initialized object &!",
2642 Nod, U_Ent);
2643 end if;
2644
2645 return;
2646 end if;
2647
2648 -- Otherwise look at the identifier and see if it is OK.
2649
2650 if Ekind (Ent) = E_Named_Integer
2651 or else
2652 Ekind (Ent) = E_Named_Real
2653 or else
2654 Is_Type (Ent)
2655 then
2656 return;
2657
2658 elsif
2659 Ekind (Ent) = E_Constant
2660 or else
2661 Ekind (Ent) = E_In_Parameter
2662 then
2663 -- This is the case where we must have Ent defined
2664 -- before U_Ent. Clearly if they are in different
2665 -- units this requirement is met since the unit
2666 -- containing Ent is already processed.
2667
2668 if not In_Same_Source_Unit (Ent, U_Ent) then
2669 return;
2670
2671 -- Otherwise location of Ent must be before the
2672 -- location of U_Ent, that's what prior defined means.
2673
2674 elsif Sloc (Ent) < Loc_U_Ent then
2675 return;
2676
2677 else
2678 Error_Msg_NE
2679 ("invalid address clause for initialized object &!",
2680 Nod, U_Ent);
2681 Error_Msg_Name_1 := Chars (Ent);
2682 Error_Msg_Name_2 := Chars (U_Ent);
2683 Error_Msg_N
2684 ("\% must be defined before % ('R'M 13.1(22))!",
2685 Nod);
2686 end if;
2687
2688 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
2689 Check_Expr_Constants (Original_Node (Nod));
2690
2691 else
2692 Error_Msg_NE
2693 ("invalid address clause for initialized object &!",
2694 Nod, U_Ent);
2695
2696 if Comes_From_Source (Ent) then
2697 Error_Msg_Name_1 := Chars (Ent);
2698 Error_Msg_N
2699 ("\reference to variable% not allowed"
2700 & " ('R'M 13.1(22))!", Nod);
2701 else
2702 Error_Msg_N
2703 ("non-static expression not allowed"
2704 & " ('R'M 13.1(22))!", Nod);
2705 end if;
2706 end if;
2707
2708 when N_Integer_Literal =>
2709
2710 -- If this is a rewritten unchecked conversion, in a system
2711 -- where Address is an integer type, always use the base type
2712 -- for a literal value. This is user-friendly and prevents
2713 -- order-of-elaboration issues with instances of unchecked
2714 -- conversion.
2715
2716 if Nkind (Original_Node (Nod)) = N_Function_Call then
2717 Set_Etype (Nod, Base_Type (Etype (Nod)));
2718 end if;
2719
2720 when N_Real_Literal |
2721 N_String_Literal |
2722 N_Character_Literal =>
2723 return;
2724
2725 when N_Range =>
2726 Check_Expr_Constants (Low_Bound (Nod));
2727 Check_Expr_Constants (High_Bound (Nod));
2728
2729 when N_Explicit_Dereference =>
2730 Check_Expr_Constants (Prefix (Nod));
2731
2732 when N_Indexed_Component =>
2733 Check_Expr_Constants (Prefix (Nod));
2734 Check_List_Constants (Expressions (Nod));
2735
2736 when N_Slice =>
2737 Check_Expr_Constants (Prefix (Nod));
2738 Check_Expr_Constants (Discrete_Range (Nod));
2739
2740 when N_Selected_Component =>
2741 Check_Expr_Constants (Prefix (Nod));
2742
2743 when N_Attribute_Reference =>
2744
2745 if Attribute_Name (Nod) = Name_Address
2746 or else
2747 Attribute_Name (Nod) = Name_Access
2748 or else
2749 Attribute_Name (Nod) = Name_Unchecked_Access
2750 or else
2751 Attribute_Name (Nod) = Name_Unrestricted_Access
2752 then
2753 Check_At_Constant_Address (Prefix (Nod));
2754
2755 else
2756 Check_Expr_Constants (Prefix (Nod));
2757 Check_List_Constants (Expressions (Nod));
2758 end if;
2759
2760 when N_Aggregate =>
2761 Check_List_Constants (Component_Associations (Nod));
2762 Check_List_Constants (Expressions (Nod));
2763
2764 when N_Component_Association =>
2765 Check_Expr_Constants (Expression (Nod));
2766
2767 when N_Extension_Aggregate =>
2768 Check_Expr_Constants (Ancestor_Part (Nod));
2769 Check_List_Constants (Component_Associations (Nod));
2770 Check_List_Constants (Expressions (Nod));
2771
2772 when N_Null =>
2773 return;
2774
2775 when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In =>
2776 Check_Expr_Constants (Left_Opnd (Nod));
2777 Check_Expr_Constants (Right_Opnd (Nod));
2778
2779 when N_Unary_Op =>
2780 Check_Expr_Constants (Right_Opnd (Nod));
2781
2782 when N_Type_Conversion |
2783 N_Qualified_Expression |
2784 N_Allocator =>
2785 Check_Expr_Constants (Expression (Nod));
2786
2787 when N_Unchecked_Type_Conversion =>
2788 Check_Expr_Constants (Expression (Nod));
2789
2790 -- If this is a rewritten unchecked conversion, subtypes
2791 -- in this node are those created within the instance.
2792 -- To avoid order of elaboration issues, replace them
2793 -- with their base types. Note that address clauses can
2794 -- cause order of elaboration problems because they are
2795 -- elaborated by the back-end at the point of definition,
2796 -- and may mention entities declared in between (as long
2797 -- as everything is static). It is user-friendly to allow
2798 -- unchecked conversions in this context.
2799
2800 if Nkind (Original_Node (Nod)) = N_Function_Call then
2801 Set_Etype (Expression (Nod),
2802 Base_Type (Etype (Expression (Nod))));
2803 Set_Etype (Nod, Base_Type (Etype (Nod)));
2804 end if;
2805
2806 when N_Function_Call =>
2807 if not Is_Pure (Entity (Name (Nod))) then
2808 Error_Msg_NE
2809 ("invalid address clause for initialized object &!",
2810 Nod, U_Ent);
2811
2812 Error_Msg_NE
2813 ("\function & is not pure ('R'M 13.1(22))!",
2814 Nod, Entity (Name (Nod)));
2815
2816 else
2817 Check_List_Constants (Parameter_Associations (Nod));
2818 end if;
2819
2820 when N_Parameter_Association =>
2821 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
2822
2823 when others =>
2824 Error_Msg_NE
2825 ("invalid address clause for initialized object &!",
2826 Nod, U_Ent);
2827 Error_Msg_NE
2828 ("\must be constant defined before& ('R'M 13.1(22))!",
2829 Nod, U_Ent);
2830 end case;
2831 end Check_Expr_Constants;
2832
2833 --------------------------
2834 -- Check_List_Constants --
2835 --------------------------
2836
2837 procedure Check_List_Constants (Lst : List_Id) is
2838 Nod1 : Node_Id;
2839
2840 begin
2841 if Present (Lst) then
2842 Nod1 := First (Lst);
2843 while Present (Nod1) loop
2844 Check_Expr_Constants (Nod1);
2845 Next (Nod1);
2846 end loop;
2847 end if;
2848 end Check_List_Constants;
2849
2850 -- Start of processing for Check_Constant_Address_Clause
2851
2852 begin
2853 Check_Expr_Constants (Expr);
2854 end Check_Constant_Address_Clause;
2855
2856 ----------------
2857 -- Check_Size --
2858 ----------------
2859
2860 procedure Check_Size
2861 (N : Node_Id;
2862 T : Entity_Id;
2863 Siz : Uint;
2864 Biased : out Boolean)
2865 is
2866 UT : constant Entity_Id := Underlying_Type (T);
2867 M : Uint;
2868
2869 begin
2870 Biased := False;
2871
2872 -- Dismiss cases for generic types or types with previous errors
2873
2874 if No (UT)
2875 or else UT = Any_Type
2876 or else Is_Generic_Type (UT)
2877 or else Is_Generic_Type (Root_Type (UT))
2878 then
2879 return;
2880
2881 -- Check case of bit packed array
2882
2883 elsif Is_Array_Type (UT)
2884 and then Known_Static_Component_Size (UT)
2885 and then Is_Bit_Packed_Array (UT)
2886 then
2887 declare
2888 Asiz : Uint;
2889 Indx : Node_Id;
2890 Ityp : Entity_Id;
2891
2892 begin
2893 Asiz := Component_Size (UT);
2894 Indx := First_Index (UT);
2895 loop
2896 Ityp := Etype (Indx);
2897
2898 -- If non-static bound, then we are not in the business of
2899 -- trying to check the length, and indeed an error will be
2900 -- issued elsewhere, since sizes of non-static array types
2901 -- cannot be set implicitly or explicitly.
2902
2903 if not Is_Static_Subtype (Ityp) then
2904 return;
2905 end if;
2906
2907 -- Otherwise accumulate next dimension
2908
2909 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
2910 Expr_Value (Type_Low_Bound (Ityp)) +
2911 Uint_1);
2912
2913 Next_Index (Indx);
2914 exit when No (Indx);
2915 end loop;
2916
2917 if Asiz <= Siz then
2918 return;
2919 else
2920 Error_Msg_Uint_1 := Asiz;
2921 Error_Msg_NE
2922 ("size for& too small, minimum allowed is ^", N, T);
2923 Set_Esize (T, Asiz);
2924 Set_RM_Size (T, Asiz);
2925 end if;
2926 end;
2927
2928 -- All other composite types are ignored
2929
2930 elsif Is_Composite_Type (UT) then
2931 return;
2932
2933 -- For fixed-point types, don't check minimum if type is not frozen,
2934 -- since we don't know all the characteristics of the type that can
2935 -- affect the size (e.g. a specified small) till freeze time.
2936
2937 elsif Is_Fixed_Point_Type (UT)
2938 and then not Is_Frozen (UT)
2939 then
2940 null;
2941
2942 -- Cases for which a minimum check is required
2943
2944 else
2945 -- Ignore if specified size is correct for the type
2946
2947 if Known_Esize (UT) and then Siz = Esize (UT) then
2948 return;
2949 end if;
2950
2951 -- Otherwise get minimum size
2952
2953 M := UI_From_Int (Minimum_Size (UT));
2954
2955 if Siz < M then
2956
2957 -- Size is less than minimum size, but one possibility remains
2958 -- that we can manage with the new size if we bias the type
2959
2960 M := UI_From_Int (Minimum_Size (UT, Biased => True));
2961
2962 if Siz < M then
2963 Error_Msg_Uint_1 := M;
2964 Error_Msg_NE
2965 ("size for& too small, minimum allowed is ^", N, T);
2966 Set_Esize (T, M);
2967 Set_RM_Size (T, M);
2968 else
2969 Biased := True;
2970 end if;
2971 end if;
2972 end if;
2973 end Check_Size;
2974
2975 -------------------------
2976 -- Get_Alignment_Value --
2977 -------------------------
2978
2979 function Get_Alignment_Value (Expr : Node_Id) return Uint is
2980 Align : constant Uint := Static_Integer (Expr);
2981
2982 begin
2983 if Align = No_Uint then
2984 return No_Uint;
2985
2986 elsif Align <= 0 then
2987 Error_Msg_N ("alignment value must be positive", Expr);
2988 return No_Uint;
2989
2990 else
2991 for J in Int range 0 .. 64 loop
2992 declare
2993 M : constant Uint := Uint_2 ** J;
2994
2995 begin
2996 exit when M = Align;
2997
2998 if M > Align then
2999 Error_Msg_N
3000 ("alignment value must be power of 2", Expr);
3001 return No_Uint;
3002 end if;
3003 end;
3004 end loop;
3005
3006 return Align;
3007 end if;
3008 end Get_Alignment_Value;
3009
3010 ----------------
3011 -- Initialize --
3012 ----------------
3013
3014 procedure Initialize is
3015 begin
3016 Unchecked_Conversions.Init;
3017 end Initialize;
3018
3019 -------------------------
3020 -- Is_Operational_Item --
3021 -------------------------
3022
3023 function Is_Operational_Item (N : Node_Id) return Boolean is
3024 begin
3025 if Nkind (N) /= N_Attribute_Definition_Clause then
3026 return False;
3027 else
3028 declare
3029 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3030
3031 begin
3032 return Id = Attribute_Input
3033 or else Id = Attribute_Output
3034 or else Id = Attribute_Read
3035 or else Id = Attribute_Write
3036 or else Id = Attribute_External_Tag;
3037 end;
3038 end if;
3039 end Is_Operational_Item;
3040
3041 --------------------------------------
3042 -- Mark_Aliased_Address_As_Volatile --
3043 --------------------------------------
3044
3045 procedure Mark_Aliased_Address_As_Volatile (N : Node_Id) is
3046 Ent : constant Entity_Id := Address_Aliased_Entity (N);
3047
3048 begin
3049 if Present (Ent) then
3050 Set_Treat_As_Volatile (Ent);
3051 end if;
3052 end Mark_Aliased_Address_As_Volatile;
3053
3054 ------------------
3055 -- Minimum_Size --
3056 ------------------
3057
3058 function Minimum_Size
3059 (T : Entity_Id;
3060 Biased : Boolean := False) return Nat
3061 is
3062 Lo : Uint := No_Uint;
3063 Hi : Uint := No_Uint;
3064 LoR : Ureal := No_Ureal;
3065 HiR : Ureal := No_Ureal;
3066 LoSet : Boolean := False;
3067 HiSet : Boolean := False;
3068 B : Uint;
3069 S : Nat;
3070 Ancest : Entity_Id;
3071 R_Typ : constant Entity_Id := Root_Type (T);
3072
3073 begin
3074 -- If bad type, return 0
3075
3076 if T = Any_Type then
3077 return 0;
3078
3079 -- For generic types, just return zero. There cannot be any legitimate
3080 -- need to know such a size, but this routine may be called with a
3081 -- generic type as part of normal processing.
3082
3083 elsif Is_Generic_Type (R_Typ)
3084 or else R_Typ = Any_Type
3085 then
3086 return 0;
3087
3088 -- Access types. Normally an access type cannot have a size smaller
3089 -- than the size of System.Address. The exception is on VMS, where
3090 -- we have short and long addresses, and it is possible for an access
3091 -- type to have a short address size (and thus be less than the size
3092 -- of System.Address itself). We simply skip the check for VMS, and
3093 -- leave the back end to do the check.
3094
3095 elsif Is_Access_Type (T) then
3096 if OpenVMS_On_Target then
3097 return 0;
3098 else
3099 return System_Address_Size;
3100 end if;
3101
3102 -- Floating-point types
3103
3104 elsif Is_Floating_Point_Type (T) then
3105 return UI_To_Int (Esize (R_Typ));
3106
3107 -- Discrete types
3108
3109 elsif Is_Discrete_Type (T) then
3110
3111 -- The following loop is looking for the nearest compile time
3112 -- known bounds following the ancestor subtype chain. The idea
3113 -- is to find the most restrictive known bounds information.
3114
3115 Ancest := T;
3116 loop
3117 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3118 return 0;
3119 end if;
3120
3121 if not LoSet then
3122 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3123 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3124 LoSet := True;
3125 exit when HiSet;
3126 end if;
3127 end if;
3128
3129 if not HiSet then
3130 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3131 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3132 HiSet := True;
3133 exit when LoSet;
3134 end if;
3135 end if;
3136
3137 Ancest := Ancestor_Subtype (Ancest);
3138
3139 if No (Ancest) then
3140 Ancest := Base_Type (T);
3141
3142 if Is_Generic_Type (Ancest) then
3143 return 0;
3144 end if;
3145 end if;
3146 end loop;
3147
3148 -- Fixed-point types. We can't simply use Expr_Value to get the
3149 -- Corresponding_Integer_Value values of the bounds, since these
3150 -- do not get set till the type is frozen, and this routine can
3151 -- be called before the type is frozen. Similarly the test for
3152 -- bounds being static needs to include the case where we have
3153 -- unanalyzed real literals for the same reason.
3154
3155 elsif Is_Fixed_Point_Type (T) then
3156
3157 -- The following loop is looking for the nearest compile time
3158 -- known bounds following the ancestor subtype chain. The idea
3159 -- is to find the most restrictive known bounds information.
3160
3161 Ancest := T;
3162 loop
3163 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3164 return 0;
3165 end if;
3166
3167 if not LoSet then
3168 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3169 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3170 then
3171 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3172 LoSet := True;
3173 exit when HiSet;
3174 end if;
3175 end if;
3176
3177 if not HiSet then
3178 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3179 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3180 then
3181 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3182 HiSet := True;
3183 exit when LoSet;
3184 end if;
3185 end if;
3186
3187 Ancest := Ancestor_Subtype (Ancest);
3188
3189 if No (Ancest) then
3190 Ancest := Base_Type (T);
3191
3192 if Is_Generic_Type (Ancest) then
3193 return 0;
3194 end if;
3195 end if;
3196 end loop;
3197
3198 Lo := UR_To_Uint (LoR / Small_Value (T));
3199 Hi := UR_To_Uint (HiR / Small_Value (T));
3200
3201 -- No other types allowed
3202
3203 else
3204 raise Program_Error;
3205 end if;
3206
3207 -- Fall through with Hi and Lo set. Deal with biased case.
3208
3209 if (Biased and then not Is_Fixed_Point_Type (T))
3210 or else Has_Biased_Representation (T)
3211 then
3212 Hi := Hi - Lo;
3213 Lo := Uint_0;
3214 end if;
3215
3216 -- Signed case. Note that we consider types like range 1 .. -1 to be
3217 -- signed for the purpose of computing the size, since the bounds
3218 -- have to be accomodated in the base type.
3219
3220 if Lo < 0 or else Hi < 0 then
3221 S := 1;
3222 B := Uint_1;
3223
3224 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3225 -- Note that we accommodate the case where the bounds cross. This
3226 -- can happen either because of the way the bounds are declared
3227 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3228
3229 while Lo < -B
3230 or else Hi < -B
3231 or else Lo >= B
3232 or else Hi >= B
3233 loop
3234 B := Uint_2 ** S;
3235 S := S + 1;
3236 end loop;
3237
3238 -- Unsigned case
3239
3240 else
3241 -- If both bounds are positive, make sure that both are represen-
3242 -- table in the case where the bounds are crossed. This can happen
3243 -- either because of the way the bounds are declared, or because of
3244 -- the algorithm in Freeze_Fixed_Point_Type.
3245
3246 if Lo > Hi then
3247 Hi := Lo;
3248 end if;
3249
3250 -- S = size, (can accommodate 0 .. (2**size - 1))
3251
3252 S := 0;
3253 while Hi >= Uint_2 ** S loop
3254 S := S + 1;
3255 end loop;
3256 end if;
3257
3258 return S;
3259 end Minimum_Size;
3260
3261 -------------------------
3262 -- New_Stream_Function --
3263 -------------------------
3264
3265 procedure New_Stream_Function
3266 (N : Node_Id;
3267 Ent : Entity_Id;
3268 Subp : Entity_Id;
3269 Nam : TSS_Name_Type)
3270 is
3271 Loc : constant Source_Ptr := Sloc (N);
3272 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3273 Subp_Id : Entity_Id;
3274 Subp_Decl : Node_Id;
3275 F : Entity_Id;
3276 Etyp : Entity_Id;
3277
3278 function Build_Spec return Node_Id;
3279 -- Used for declaration and renaming declaration, so that this is
3280 -- treated as a renaming_as_body.
3281
3282 ----------------
3283 -- Build_Spec --
3284 ----------------
3285
3286 function Build_Spec return Node_Id is
3287 begin
3288 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3289
3290 return
3291 Make_Function_Specification (Loc,
3292 Defining_Unit_Name => Subp_Id,
3293 Parameter_Specifications =>
3294 New_List (
3295 Make_Parameter_Specification (Loc,
3296 Defining_Identifier =>
3297 Make_Defining_Identifier (Loc, Name_S),
3298 Parameter_Type =>
3299 Make_Access_Definition (Loc,
3300 Subtype_Mark =>
3301 New_Reference_To (
3302 Designated_Type (Etype (F)), Loc)))),
3303
3304 Subtype_Mark =>
3305 New_Reference_To (Etyp, Loc));
3306 end Build_Spec;
3307
3308 -- Start of processing for New_Stream_Function
3309
3310 begin
3311 F := First_Formal (Subp);
3312 Etyp := Etype (Subp);
3313
3314 if not Is_Tagged_Type (Ent) then
3315 Subp_Decl :=
3316 Make_Subprogram_Declaration (Loc,
3317 Specification => Build_Spec);
3318 Insert_Action (N, Subp_Decl);
3319 end if;
3320
3321 Subp_Decl :=
3322 Make_Subprogram_Renaming_Declaration (Loc,
3323 Specification => Build_Spec,
3324 Name => New_Reference_To (Subp, Loc));
3325
3326 if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then
3327 Set_TSS (Base_Type (Ent), Subp_Id);
3328 else
3329 Insert_Action (N, Subp_Decl);
3330 Copy_TSS (Subp_Id, Base_Type (Ent));
3331 end if;
3332 end New_Stream_Function;
3333
3334 --------------------------
3335 -- New_Stream_Procedure --
3336 --------------------------
3337
3338 procedure New_Stream_Procedure
3339 (N : Node_Id;
3340 Ent : Entity_Id;
3341 Subp : Entity_Id;
3342 Nam : TSS_Name_Type;
3343 Out_P : Boolean := False)
3344 is
3345 Loc : constant Source_Ptr := Sloc (N);
3346 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3347 Subp_Id : Entity_Id;
3348 Subp_Decl : Node_Id;
3349 F : Entity_Id;
3350 Etyp : Entity_Id;
3351
3352 function Build_Spec return Node_Id;
3353 -- Used for declaration and renaming declaration, so that this is
3354 -- treated as a renaming_as_body.
3355
3356 ----------------
3357 -- Build_Spec --
3358 ----------------
3359
3360 function Build_Spec return Node_Id is
3361 begin
3362 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3363
3364 return
3365 Make_Procedure_Specification (Loc,
3366 Defining_Unit_Name => Subp_Id,
3367 Parameter_Specifications =>
3368 New_List (
3369 Make_Parameter_Specification (Loc,
3370 Defining_Identifier =>
3371 Make_Defining_Identifier (Loc, Name_S),
3372 Parameter_Type =>
3373 Make_Access_Definition (Loc,
3374 Subtype_Mark =>
3375 New_Reference_To (
3376 Designated_Type (Etype (F)), Loc))),
3377
3378 Make_Parameter_Specification (Loc,
3379 Defining_Identifier =>
3380 Make_Defining_Identifier (Loc, Name_V),
3381 Out_Present => Out_P,
3382 Parameter_Type =>
3383 New_Reference_To (Etyp, Loc))));
3384 end Build_Spec;
3385
3386 -- Start of processing for New_Stream_Procedure
3387
3388 begin
3389 F := First_Formal (Subp);
3390 Etyp := Etype (Next_Formal (F));
3391
3392 if not Is_Tagged_Type (Ent) then
3393 Subp_Decl :=
3394 Make_Subprogram_Declaration (Loc,
3395 Specification => Build_Spec);
3396 Insert_Action (N, Subp_Decl);
3397 end if;
3398
3399 Subp_Decl :=
3400 Make_Subprogram_Renaming_Declaration (Loc,
3401 Specification => Build_Spec,
3402 Name => New_Reference_To (Subp, Loc));
3403
3404 if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then
3405 Set_TSS (Base_Type (Ent), Subp_Id);
3406 else
3407 Insert_Action (N, Subp_Decl);
3408 Copy_TSS (Subp_Id, Base_Type (Ent));
3409 end if;
3410 end New_Stream_Procedure;
3411
3412 ---------------------
3413 -- Record_Rep_Item --
3414 ---------------------
3415
3416 procedure Record_Rep_Item (T : Entity_Id; N : Node_Id) is
3417 begin
3418 Set_Next_Rep_Item (N, First_Rep_Item (T));
3419 Set_First_Rep_Item (T, N);
3420 end Record_Rep_Item;
3421
3422 ------------------------
3423 -- Rep_Item_Too_Early --
3424 ------------------------
3425
3426 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3427 begin
3428 -- Cannot apply rep items that are not operational items
3429 -- to generic types
3430
3431 if Is_Operational_Item (N) then
3432 return False;
3433
3434 elsif Is_Type (T)
3435 and then Is_Generic_Type (Root_Type (T))
3436 then
3437 Error_Msg_N
3438 ("representation item not allowed for generic type", N);
3439 return True;
3440 end if;
3441
3442 -- Otherwise check for incompleted type
3443
3444 if Is_Incomplete_Or_Private_Type (T)
3445 and then No (Underlying_Type (T))
3446 then
3447 Error_Msg_N
3448 ("representation item must be after full type declaration", N);
3449 return True;
3450
3451 -- If the type has incompleted components, a representation clause is
3452 -- illegal but stream attributes and Convention pragmas are correct.
3453
3454 elsif Has_Private_Component (T) then
3455 if Nkind (N) = N_Pragma then
3456 return False;
3457 else
3458 Error_Msg_N
3459 ("representation item must appear after type is fully defined",
3460 N);
3461 return True;
3462 end if;
3463 else
3464 return False;
3465 end if;
3466 end Rep_Item_Too_Early;
3467
3468 -----------------------
3469 -- Rep_Item_Too_Late --
3470 -----------------------
3471
3472 function Rep_Item_Too_Late
3473 (T : Entity_Id;
3474 N : Node_Id;
3475 FOnly : Boolean := False) return Boolean
3476 is
3477 S : Entity_Id;
3478 Parent_Type : Entity_Id;
3479
3480 procedure Too_Late;
3481 -- Output the too late message
3482
3483 procedure Too_Late is
3484 begin
3485 Error_Msg_N ("representation item appears too late!", N);
3486 end Too_Late;
3487
3488 -- Start of processing for Rep_Item_Too_Late
3489
3490 begin
3491 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
3492 -- types, which may be frozen if they appear in a representation clause
3493 -- for a local type.
3494
3495 if Is_Frozen (T)
3496 and then not From_With_Type (T)
3497 then
3498 Too_Late;
3499 S := First_Subtype (T);
3500
3501 if Present (Freeze_Node (S)) then
3502 Error_Msg_NE
3503 ("?no more representation items for }!", Freeze_Node (S), S);
3504 end if;
3505
3506 return True;
3507
3508 -- Check for case of non-tagged derived type whose parent either has
3509 -- primitive operations, or is a by reference type (RM 13.1(10)).
3510
3511 elsif Is_Type (T)
3512 and then not FOnly
3513 and then Is_Derived_Type (T)
3514 and then not Is_Tagged_Type (T)
3515 then
3516 Parent_Type := Etype (Base_Type (T));
3517
3518 if Has_Primitive_Operations (Parent_Type) then
3519 Too_Late;
3520 Error_Msg_NE
3521 ("primitive operations already defined for&!", N, Parent_Type);
3522 return True;
3523
3524 elsif Is_By_Reference_Type (Parent_Type) then
3525 Too_Late;
3526 Error_Msg_NE
3527 ("parent type & is a by reference type!", N, Parent_Type);
3528 return True;
3529 end if;
3530 end if;
3531
3532 -- No error, link item into head of chain of rep items for the entity
3533
3534 Record_Rep_Item (T, N);
3535 return False;
3536 end Rep_Item_Too_Late;
3537
3538 -------------------------
3539 -- Same_Representation --
3540 -------------------------
3541
3542 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
3543 T1 : constant Entity_Id := Underlying_Type (Typ1);
3544 T2 : constant Entity_Id := Underlying_Type (Typ2);
3545
3546 begin
3547 -- A quick check, if base types are the same, then we definitely have
3548 -- the same representation, because the subtype specific representation
3549 -- attributes (Size and Alignment) do not affect representation from
3550 -- the point of view of this test.
3551
3552 if Base_Type (T1) = Base_Type (T2) then
3553 return True;
3554
3555 elsif Is_Private_Type (Base_Type (T2))
3556 and then Base_Type (T1) = Full_View (Base_Type (T2))
3557 then
3558 return True;
3559 end if;
3560
3561 -- Tagged types never have differing representations
3562
3563 if Is_Tagged_Type (T1) then
3564 return True;
3565 end if;
3566
3567 -- Representations are definitely different if conventions differ
3568
3569 if Convention (T1) /= Convention (T2) then
3570 return False;
3571 end if;
3572
3573 -- Representations are different if component alignments differ
3574
3575 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
3576 and then
3577 (Is_Record_Type (T2) or else Is_Array_Type (T2))
3578 and then Component_Alignment (T1) /= Component_Alignment (T2)
3579 then
3580 return False;
3581 end if;
3582
3583 -- For arrays, the only real issue is component size. If we know the
3584 -- component size for both arrays, and it is the same, then that's
3585 -- good enough to know we don't have a change of representation.
3586
3587 if Is_Array_Type (T1) then
3588 if Known_Component_Size (T1)
3589 and then Known_Component_Size (T2)
3590 and then Component_Size (T1) = Component_Size (T2)
3591 then
3592 return True;
3593 end if;
3594 end if;
3595
3596 -- Types definitely have same representation if neither has non-standard
3597 -- representation since default representations are always consistent.
3598 -- If only one has non-standard representation, and the other does not,
3599 -- then we consider that they do not have the same representation. They
3600 -- might, but there is no way of telling early enough.
3601
3602 if Has_Non_Standard_Rep (T1) then
3603 if not Has_Non_Standard_Rep (T2) then
3604 return False;
3605 end if;
3606 else
3607 return not Has_Non_Standard_Rep (T2);
3608 end if;
3609
3610 -- Here the two types both have non-standard representation, and we
3611 -- need to determine if they have the same non-standard representation
3612
3613 -- For arrays, we simply need to test if the component sizes are the
3614 -- same. Pragma Pack is reflected in modified component sizes, so this
3615 -- check also deals with pragma Pack.
3616
3617 if Is_Array_Type (T1) then
3618 return Component_Size (T1) = Component_Size (T2);
3619
3620 -- Tagged types always have the same representation, because it is not
3621 -- possible to specify different representations for common fields.
3622
3623 elsif Is_Tagged_Type (T1) then
3624 return True;
3625
3626 -- Case of record types
3627
3628 elsif Is_Record_Type (T1) then
3629
3630 -- Packed status must conform
3631
3632 if Is_Packed (T1) /= Is_Packed (T2) then
3633 return False;
3634
3635 -- Otherwise we must check components. Typ2 maybe a constrained
3636 -- subtype with fewer components, so we compare the components
3637 -- of the base types.
3638
3639 else
3640 Record_Case : declare
3641 CD1, CD2 : Entity_Id;
3642
3643 function Same_Rep return Boolean;
3644 -- CD1 and CD2 are either components or discriminants. This
3645 -- function tests whether the two have the same representation
3646
3647 --------------
3648 -- Same_Rep --
3649 --------------
3650
3651 function Same_Rep return Boolean is
3652 begin
3653 if No (Component_Clause (CD1)) then
3654 return No (Component_Clause (CD2));
3655
3656 else
3657 return
3658 Present (Component_Clause (CD2))
3659 and then
3660 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
3661 and then
3662 Esize (CD1) = Esize (CD2);
3663 end if;
3664 end Same_Rep;
3665
3666 -- Start processing for Record_Case
3667
3668 begin
3669 if Has_Discriminants (T1) then
3670 CD1 := First_Discriminant (T1);
3671 CD2 := First_Discriminant (T2);
3672
3673 -- The number of discriminants may be different if the
3674 -- derived type has fewer (constrained by values). The
3675 -- invisible discriminants retain the representation of
3676 -- the original, so the discrepancy does not per se
3677 -- indicate a different representation.
3678
3679 while Present (CD1)
3680 and then Present (CD2)
3681 loop
3682 if not Same_Rep then
3683 return False;
3684 else
3685 Next_Discriminant (CD1);
3686 Next_Discriminant (CD2);
3687 end if;
3688 end loop;
3689 end if;
3690
3691 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
3692 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
3693
3694 while Present (CD1) loop
3695 if not Same_Rep then
3696 return False;
3697 else
3698 Next_Component (CD1);
3699 Next_Component (CD2);
3700 end if;
3701 end loop;
3702
3703 return True;
3704 end Record_Case;
3705 end if;
3706
3707 -- For enumeration types, we must check each literal to see if the
3708 -- representation is the same. Note that we do not permit enumeration
3709 -- reprsentation clauses for Character and Wide_Character, so these
3710 -- cases were already dealt with.
3711
3712 elsif Is_Enumeration_Type (T1) then
3713
3714 Enumeration_Case : declare
3715 L1, L2 : Entity_Id;
3716
3717 begin
3718 L1 := First_Literal (T1);
3719 L2 := First_Literal (T2);
3720
3721 while Present (L1) loop
3722 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
3723 return False;
3724 else
3725 Next_Literal (L1);
3726 Next_Literal (L2);
3727 end if;
3728 end loop;
3729
3730 return True;
3731
3732 end Enumeration_Case;
3733
3734 -- Any other types have the same representation for these purposes
3735
3736 else
3737 return True;
3738 end if;
3739 end Same_Representation;
3740
3741 --------------------
3742 -- Set_Enum_Esize --
3743 --------------------
3744
3745 procedure Set_Enum_Esize (T : Entity_Id) is
3746 Lo : Uint;
3747 Hi : Uint;
3748 Sz : Nat;
3749
3750 begin
3751 Init_Alignment (T);
3752
3753 -- Find the minimum standard size (8,16,32,64) that fits
3754
3755 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
3756 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
3757
3758 if Lo < 0 then
3759 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
3760 Sz := Standard_Character_Size; -- May be > 8 on some targets
3761
3762 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
3763 Sz := 16;
3764
3765 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
3766 Sz := 32;
3767
3768 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
3769 Sz := 64;
3770 end if;
3771
3772 else
3773 if Hi < Uint_2**08 then
3774 Sz := Standard_Character_Size; -- May be > 8 on some targets
3775
3776 elsif Hi < Uint_2**16 then
3777 Sz := 16;
3778
3779 elsif Hi < Uint_2**32 then
3780 Sz := 32;
3781
3782 else pragma Assert (Hi < Uint_2**63);
3783 Sz := 64;
3784 end if;
3785 end if;
3786
3787 -- That minimum is the proper size unless we have a foreign convention
3788 -- and the size required is 32 or less, in which case we bump the size
3789 -- up to 32. This is required for C and C++ and seems reasonable for
3790 -- all other foreign conventions.
3791
3792 if Has_Foreign_Convention (T)
3793 and then Esize (T) < Standard_Integer_Size
3794 then
3795 Init_Esize (T, Standard_Integer_Size);
3796
3797 else
3798 Init_Esize (T, Sz);
3799 end if;
3800 end Set_Enum_Esize;
3801
3802 -----------------------------------
3803 -- Validate_Unchecked_Conversion --
3804 -----------------------------------
3805
3806 procedure Validate_Unchecked_Conversion
3807 (N : Node_Id;
3808 Act_Unit : Entity_Id)
3809 is
3810 Source : Entity_Id;
3811 Target : Entity_Id;
3812 Vnode : Node_Id;
3813
3814 begin
3815 -- Obtain source and target types. Note that we call Ancestor_Subtype
3816 -- here because the processing for generic instantiation always makes
3817 -- subtypes, and we want the original frozen actual types.
3818
3819 -- If we are dealing with private types, then do the check on their
3820 -- fully declared counterparts if the full declarations have been
3821 -- encountered (they don't have to be visible, but they must exist!)
3822
3823 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
3824
3825 if Is_Private_Type (Source)
3826 and then Present (Underlying_Type (Source))
3827 then
3828 Source := Underlying_Type (Source);
3829 end if;
3830
3831 Target := Ancestor_Subtype (Etype (Act_Unit));
3832
3833 -- If either type is generic, the instantiation happens within a
3834 -- generic unit, and there is nothing to check. The proper check
3835 -- will happen when the enclosing generic is instantiated.
3836
3837 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
3838 return;
3839 end if;
3840
3841 if Is_Private_Type (Target)
3842 and then Present (Underlying_Type (Target))
3843 then
3844 Target := Underlying_Type (Target);
3845 end if;
3846
3847 -- Source may be unconstrained array, but not target
3848
3849 if Is_Array_Type (Target)
3850 and then not Is_Constrained (Target)
3851 then
3852 Error_Msg_N
3853 ("unchecked conversion to unconstrained array not allowed", N);
3854 return;
3855 end if;
3856
3857 -- Make entry in unchecked conversion table for later processing
3858 -- by Validate_Unchecked_Conversions, which will check sizes and
3859 -- alignments (using values set by the back-end where possible).
3860 -- This is only done if the appropriate warning is active
3861
3862 if Warn_On_Unchecked_Conversion then
3863 Unchecked_Conversions.Append
3864 (New_Val => UC_Entry'
3865 (Enode => N,
3866 Source => Source,
3867 Target => Target));
3868
3869 -- If both sizes are known statically now, then back end annotation
3870 -- is not required to do a proper check but if either size is not
3871 -- known statically, then we need the annotation.
3872
3873 if Known_Static_RM_Size (Source)
3874 and then Known_Static_RM_Size (Target)
3875 then
3876 null;
3877 else
3878 Back_Annotate_Rep_Info := True;
3879 end if;
3880 end if;
3881
3882 -- If unchecked conversion to access type, and access type is
3883 -- declared in the same unit as the unchecked conversion, then
3884 -- set the No_Strict_Aliasing flag (no strict aliasing is
3885 -- implicit in this situation).
3886
3887 if Is_Access_Type (Target) and then
3888 In_Same_Source_Unit (Target, N)
3889 then
3890 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
3891 end if;
3892
3893 -- Generate N_Validate_Unchecked_Conversion node for back end in
3894 -- case the back end needs to perform special validation checks.
3895
3896 -- Shouldn't this be in exp_ch13, since the check only gets done
3897 -- if we have full expansion and the back end is called ???
3898
3899 Vnode :=
3900 Make_Validate_Unchecked_Conversion (Sloc (N));
3901 Set_Source_Type (Vnode, Source);
3902 Set_Target_Type (Vnode, Target);
3903
3904 -- If the unchecked conversion node is in a list, just insert before
3905 -- it. If not we have some strange case, not worth bothering about.
3906
3907 if Is_List_Member (N) then
3908 Insert_After (N, Vnode);
3909 end if;
3910 end Validate_Unchecked_Conversion;
3911
3912 ------------------------------------
3913 -- Validate_Unchecked_Conversions --
3914 ------------------------------------
3915
3916 procedure Validate_Unchecked_Conversions is
3917 begin
3918 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
3919 declare
3920 T : UC_Entry renames Unchecked_Conversions.Table (N);
3921
3922 Enode : constant Node_Id := T.Enode;
3923 Source : constant Entity_Id := T.Source;
3924 Target : constant Entity_Id := T.Target;
3925
3926 Source_Siz : Uint;
3927 Target_Siz : Uint;
3928
3929 begin
3930 -- This validation check, which warns if we have unequal sizes
3931 -- for unchecked conversion, and thus potentially implementation
3932 -- dependent semantics, is one of the few occasions on which we
3933 -- use the official RM size instead of Esize. See description
3934 -- in Einfo "Handling of Type'Size Values" for details.
3935
3936 if Serious_Errors_Detected = 0
3937 and then Known_Static_RM_Size (Source)
3938 and then Known_Static_RM_Size (Target)
3939 then
3940 Source_Siz := RM_Size (Source);
3941 Target_Siz := RM_Size (Target);
3942
3943 if Source_Siz /= Target_Siz then
3944 Error_Msg_N
3945 ("types for unchecked conversion have different sizes?",
3946 Enode);
3947
3948 if All_Errors_Mode then
3949 Error_Msg_Name_1 := Chars (Source);
3950 Error_Msg_Uint_1 := Source_Siz;
3951 Error_Msg_Name_2 := Chars (Target);
3952 Error_Msg_Uint_2 := Target_Siz;
3953 Error_Msg_N
3954 ("\size of % is ^, size of % is ^?", Enode);
3955
3956 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
3957
3958 if Is_Discrete_Type (Source)
3959 and then Is_Discrete_Type (Target)
3960 then
3961 if Source_Siz > Target_Siz then
3962 Error_Msg_N
3963 ("\^ high order bits of source will be ignored?",
3964 Enode);
3965
3966 elsif Is_Unsigned_Type (Source) then
3967 Error_Msg_N
3968 ("\source will be extended with ^ high order " &
3969 "zero bits?", Enode);
3970
3971 else
3972 Error_Msg_N
3973 ("\source will be extended with ^ high order " &
3974 "sign bits?",
3975 Enode);
3976 end if;
3977
3978 elsif Source_Siz < Target_Siz then
3979 if Is_Discrete_Type (Target) then
3980 if Bytes_Big_Endian then
3981 Error_Msg_N
3982 ("\target value will include ^ undefined " &
3983 "low order bits?",
3984 Enode);
3985 else
3986 Error_Msg_N
3987 ("\target value will include ^ undefined " &
3988 "high order bits?",
3989 Enode);
3990 end if;
3991
3992 else
3993 Error_Msg_N
3994 ("\^ trailing bits of target value will be " &
3995 "undefined?", Enode);
3996 end if;
3997
3998 else pragma Assert (Source_Siz > Target_Siz);
3999 Error_Msg_N
4000 ("\^ trailing bits of source will be ignored?",
4001 Enode);
4002 end if;
4003 end if;
4004 end if;
4005 end if;
4006
4007 -- If both types are access types, we need to check the alignment.
4008 -- If the alignment of both is specified, we can do it here.
4009
4010 if Serious_Errors_Detected = 0
4011 and then Ekind (Source) in Access_Kind
4012 and then Ekind (Target) in Access_Kind
4013 and then Target_Strict_Alignment
4014 and then Present (Designated_Type (Source))
4015 and then Present (Designated_Type (Target))
4016 then
4017 declare
4018 D_Source : constant Entity_Id := Designated_Type (Source);
4019 D_Target : constant Entity_Id := Designated_Type (Target);
4020
4021 begin
4022 if Known_Alignment (D_Source)
4023 and then Known_Alignment (D_Target)
4024 then
4025 declare
4026 Source_Align : constant Uint := Alignment (D_Source);
4027 Target_Align : constant Uint := Alignment (D_Target);
4028
4029 begin
4030 if Source_Align < Target_Align
4031 and then not Is_Tagged_Type (D_Source)
4032 then
4033 Error_Msg_Uint_1 := Target_Align;
4034 Error_Msg_Uint_2 := Source_Align;
4035 Error_Msg_Node_2 := D_Source;
4036 Error_Msg_NE
4037 ("alignment of & (^) is stricter than " &
4038 "alignment of & (^)?", Enode, D_Target);
4039
4040 if All_Errors_Mode then
4041 Error_Msg_N
4042 ("\resulting access value may have invalid " &
4043 "alignment?", Enode);
4044 end if;
4045 end if;
4046 end;
4047 end if;
4048 end;
4049 end if;
4050 end;
4051 end loop;
4052 end Validate_Unchecked_Conversions;
4053
4054 end Sem_Ch13;
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