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(PREFERRED_DEBUGGING_TYPE): Use DWARF2_DEBUG.
[official-gcc.git] / gcc / ada / sem_ch13.adb
blob117dde2213144a6cbf97129bbe840693f73fa7b1
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 T : Entity_Id;
1254
1255 begin
1256 if Ekind (U_Ent) /= E_Access_Type
1257 and then Ekind (U_Ent) /= E_General_Access_Type
1258 then
1259 Error_Msg_N (
1260 "storage pool can only be given for access types", Nam);
1261 return;
1262
1263 elsif Is_Derived_Type (U_Ent) then
1264 Error_Msg_N
1265 ("storage pool cannot be given for a derived access type",
1266 Nam);
1267
1268 elsif Has_Storage_Size_Clause (U_Ent) then
1269 Error_Msg_N ("storage size already given for &", Nam);
1270 return;
1271
1272 elsif Present (Associated_Storage_Pool (U_Ent)) then
1273 Error_Msg_N ("storage pool already given for &", Nam);
1274 return;
1275 end if;
1276
1277 Analyze_And_Resolve
1278 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1279
1280 if Nkind (Expr) = N_Type_Conversion then
1281 T := Etype (Expression (Expr));
1282 else
1283 T := Etype (Expr);
1284 end if;
1285
1286 -- The Stack_Bounded_Pool is used internally for implementing
1287 -- access types with a Storage_Size. Since it only work
1288 -- properly when used on one specific type, we need to check
1289 -- that it is not highjacked improperly:
1290 -- type T is access Integer;
1291 -- for T'Storage_Size use n;
1292 -- type Q is access Float;
1293 -- for Q'Storage_Size use T'Storage_Size; -- incorrect
1294
1295 if Base_Type (T) = RTE (RE_Stack_Bounded_Pool) then
1296 Error_Msg_N ("non-sharable internal Pool", Expr);
1297 return;
1298 end if;
1299
1300 -- If the argument is a name that is not an entity name, then
1301 -- we construct a renaming operation to define an entity of
1302 -- type storage pool.
1303
1304 if not Is_Entity_Name (Expr)
1305 and then Is_Object_Reference (Expr)
1306 then
1307 Pool :=
1308 Make_Defining_Identifier (Loc,
1309 Chars => New_Internal_Name ('P'));
1310
1311 declare
1312 Rnode : constant Node_Id :=
1313 Make_Object_Renaming_Declaration (Loc,
1314 Defining_Identifier => Pool,
1315 Subtype_Mark =>
1316 New_Occurrence_Of (Etype (Expr), Loc),
1317 Name => Expr);
1318
1319 begin
1320 Insert_Before (N, Rnode);
1321 Analyze (Rnode);
1322 Set_Associated_Storage_Pool (U_Ent, Pool);
1323 end;
1324
1325 elsif Is_Entity_Name (Expr) then
1326 Pool := Entity (Expr);
1327
1328 -- If pool is a renamed object, get original one. This can
1329 -- happen with an explicit renaming, and within instances.
1330
1331 while Present (Renamed_Object (Pool))
1332 and then Is_Entity_Name (Renamed_Object (Pool))
1333 loop
1334 Pool := Entity (Renamed_Object (Pool));
1335 end loop;
1336
1337 if Present (Renamed_Object (Pool))
1338 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1339 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1340 then
1341 Pool := Entity (Expression (Renamed_Object (Pool)));
1342 end if;
1343
1344 Set_Associated_Storage_Pool (U_Ent, Pool);
1345
1346 elsif Nkind (Expr) = N_Type_Conversion
1347 and then Is_Entity_Name (Expression (Expr))
1348 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1349 then
1350 Pool := Entity (Expression (Expr));
1351 Set_Associated_Storage_Pool (U_Ent, Pool);
1352
1353 else
1354 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1355 return;
1356 end if;
1357 end Storage_Pool;
1358
1359 ----------------
1360 -- Value_Size --
1361 ----------------
1362
1363 -- Value_Size attribute definition clause
1364
1365 when Attribute_Value_Size => Value_Size : declare
1366 Size : constant Uint := Static_Integer (Expr);
1367 Biased : Boolean;
1368
1369 begin
1370 if not Is_Type (U_Ent) then
1371 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1372
1373 elsif Present
1374 (Get_Attribute_Definition_Clause
1375 (U_Ent, Attribute_Value_Size))
1376 then
1377 Error_Msg_N ("Value_Size already given for &", Nam);
1378
1379 else
1380 if Is_Elementary_Type (U_Ent) then
1381 Check_Size (Expr, U_Ent, Size, Biased);
1382 Set_Has_Biased_Representation (U_Ent, Biased);
1383 end if;
1384
1385 Set_RM_Size (U_Ent, Size);
1386 end if;
1387 end Value_Size;
1388
1389 -----------
1390 -- Write --
1391 -----------
1392
1393 -- Write attribute definition clause
1394 -- check for class-wide case will be performed later
1395
1396 when Attribute_Write => Write : declare
1397 Subp : Entity_Id := Empty;
1398 I : Interp_Index;
1399 It : Interp;
1400 Pnam : Entity_Id;
1401
1402 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
1403 -- Return true if the entity is a procedure with an
1404 -- appropriate profile for the write attribute.
1405
1406 ----------------------
1407 -- Has_Good_Profile --
1408 ----------------------
1409
1410 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
1411 F : Entity_Id;
1412 Ok : Boolean := False;
1413
1414 begin
1415 if Ekind (Subp) = E_Procedure then
1416 F := First_Formal (Subp);
1417
1418 if Present (F) then
1419 if Ekind (Etype (F)) = E_Anonymous_Access_Type
1420 and then
1421 Designated_Type (Etype (F)) =
1422 Class_Wide_Type (RTE (RE_Root_Stream_Type))
1423 then
1424 Next_Formal (F);
1425 Ok := Present (F)
1426 and then Parameter_Mode (F) = E_In_Parameter
1427 and then Base_Type (Etype (F)) = Base_Type (Ent)
1428 and then No (Next_Formal (F));
1429 end if;
1430 end if;
1431 end if;
1432
1433 return Ok;
1434 end Has_Good_Profile;
1435
1436 -- Start of processing for Write attribute definition
1437
1438 begin
1439 FOnly := True;
1440
1441 if not Is_Type (U_Ent) then
1442 Error_Msg_N ("local name must be a subtype", Nam);
1443 return;
1444 end if;
1445
1446 Pnam := TSS (Base_Type (U_Ent), TSS_Stream_Write);
1447
1448 if Present (Pnam)
1449 and then Base_Type (Etype (Next_Formal (First_Formal (Pnam))))
1450 = Base_Type (U_Ent)
1451 then
1452 Error_Msg_Sloc := Sloc (Pnam);
1453 Error_Msg_N ("write attribute already defined #", Nam);
1454 return;
1455 end if;
1456
1457 Analyze (Expr);
1458
1459 if Is_Entity_Name (Expr) then
1460 if not Is_Overloaded (Expr) then
1461 if Has_Good_Profile (Entity (Expr)) then
1462 Subp := Entity (Expr);
1463 end if;
1464
1465 else
1466 Get_First_Interp (Expr, I, It);
1467
1468 while Present (It.Nam) loop
1469 if Has_Good_Profile (It.Nam) then
1470 Subp := It.Nam;
1471 exit;
1472 end if;
1473
1474 Get_Next_Interp (I, It);
1475 end loop;
1476 end if;
1477 end if;
1478
1479 if Present (Subp) then
1480 Set_Entity (Expr, Subp);
1481 Set_Etype (Expr, Etype (Subp));
1482 New_Stream_Procedure (N, U_Ent, Subp, TSS_Stream_Write);
1483 else
1484 Error_Msg_N ("incorrect expression for write attribute", Expr);
1485 return;
1486 end if;
1487 end Write;
1488
1489 -- All other attributes cannot be set
1490
1491 when others =>
1492 Error_Msg_N
1493 ("attribute& cannot be set with definition clause", N);
1494
1495 end case;
1496
1497 -- The test for the type being frozen must be performed after
1498 -- any expression the clause has been analyzed since the expression
1499 -- itself might cause freezing that makes the clause illegal.
1500
1501 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1502 return;
1503 end if;
1504 end Analyze_Attribute_Definition_Clause;
1505
1506 ----------------------------
1507 -- Analyze_Code_Statement --
1508 ----------------------------
1509
1510 procedure Analyze_Code_Statement (N : Node_Id) is
1511 HSS : constant Node_Id := Parent (N);
1512 SBody : constant Node_Id := Parent (HSS);
1513 Subp : constant Entity_Id := Current_Scope;
1514 Stmt : Node_Id;
1515 Decl : Node_Id;
1516 StmtO : Node_Id;
1517 DeclO : Node_Id;
1518
1519 begin
1520 -- Analyze and check we get right type, note that this implements the
1521 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1522 -- is the only way that Asm_Insn could possibly be visible.
1523
1524 Analyze_And_Resolve (Expression (N));
1525
1526 if Etype (Expression (N)) = Any_Type then
1527 return;
1528 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1529 Error_Msg_N ("incorrect type for code statement", N);
1530 return;
1531 end if;
1532
1533 -- Make sure we appear in the handled statement sequence of a
1534 -- subprogram (RM 13.8(3)).
1535
1536 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1537 or else Nkind (SBody) /= N_Subprogram_Body
1538 then
1539 Error_Msg_N
1540 ("code statement can only appear in body of subprogram", N);
1541 return;
1542 end if;
1543
1544 -- Do remaining checks (RM 13.8(3)) if not already done
1545
1546 if not Is_Machine_Code_Subprogram (Subp) then
1547 Set_Is_Machine_Code_Subprogram (Subp);
1548
1549 -- No exception handlers allowed
1550
1551 if Present (Exception_Handlers (HSS)) then
1552 Error_Msg_N
1553 ("exception handlers not permitted in machine code subprogram",
1554 First (Exception_Handlers (HSS)));
1555 end if;
1556
1557 -- No declarations other than use clauses and pragmas (we allow
1558 -- certain internally generated declarations as well).
1559
1560 Decl := First (Declarations (SBody));
1561 while Present (Decl) loop
1562 DeclO := Original_Node (Decl);
1563 if Comes_From_Source (DeclO)
1564 and then Nkind (DeclO) /= N_Pragma
1565 and then Nkind (DeclO) /= N_Use_Package_Clause
1566 and then Nkind (DeclO) /= N_Use_Type_Clause
1567 and then Nkind (DeclO) /= N_Implicit_Label_Declaration
1568 then
1569 Error_Msg_N
1570 ("this declaration not allowed in machine code subprogram",
1571 DeclO);
1572 end if;
1573
1574 Next (Decl);
1575 end loop;
1576
1577 -- No statements other than code statements, pragmas, and labels.
1578 -- Again we allow certain internally generated statements.
1579
1580 Stmt := First (Statements (HSS));
1581 while Present (Stmt) loop
1582 StmtO := Original_Node (Stmt);
1583 if Comes_From_Source (StmtO)
1584 and then Nkind (StmtO) /= N_Pragma
1585 and then Nkind (StmtO) /= N_Label
1586 and then Nkind (StmtO) /= N_Code_Statement
1587 then
1588 Error_Msg_N
1589 ("this statement is not allowed in machine code subprogram",
1590 StmtO);
1591 end if;
1592
1593 Next (Stmt);
1594 end loop;
1595 end if;
1596 end Analyze_Code_Statement;
1597
1598 -----------------------------------------------
1599 -- Analyze_Enumeration_Representation_Clause --
1600 -----------------------------------------------
1601
1602 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1603 Ident : constant Node_Id := Identifier (N);
1604 Aggr : constant Node_Id := Array_Aggregate (N);
1605 Enumtype : Entity_Id;
1606 Elit : Entity_Id;
1607 Expr : Node_Id;
1608 Assoc : Node_Id;
1609 Choice : Node_Id;
1610 Val : Uint;
1611 Err : Boolean := False;
1612
1613 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1614 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1615 Min : Uint;
1616 Max : Uint;
1617
1618 begin
1619 -- First some basic error checks
1620
1621 Find_Type (Ident);
1622 Enumtype := Entity (Ident);
1623
1624 if Enumtype = Any_Type
1625 or else Rep_Item_Too_Early (Enumtype, N)
1626 then
1627 return;
1628 else
1629 Enumtype := Underlying_Type (Enumtype);
1630 end if;
1631
1632 if not Is_Enumeration_Type (Enumtype) then
1633 Error_Msg_NE
1634 ("enumeration type required, found}",
1635 Ident, First_Subtype (Enumtype));
1636 return;
1637 end if;
1638
1639 -- Ignore rep clause on generic actual type. This will already have
1640 -- been flagged on the template as an error, and this is the safest
1641 -- way to ensure we don't get a junk cascaded message in the instance.
1642
1643 if Is_Generic_Actual_Type (Enumtype) then
1644 return;
1645
1646 -- Type must be in current scope
1647
1648 elsif Scope (Enumtype) /= Current_Scope then
1649 Error_Msg_N ("type must be declared in this scope", Ident);
1650 return;
1651
1652 -- Type must be a first subtype
1653
1654 elsif not Is_First_Subtype (Enumtype) then
1655 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1656 return;
1657
1658 -- Ignore duplicate rep clause
1659
1660 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1661 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1662 return;
1663
1664 -- Don't allow rep clause if root type is standard [wide_]character
1665
1666 elsif Root_Type (Enumtype) = Standard_Character
1667 or else Root_Type (Enumtype) = Standard_Wide_Character
1668 then
1669 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1670 return;
1671
1672 -- All tests passed, so set rep clause in place
1673
1674 else
1675 Set_Has_Enumeration_Rep_Clause (Enumtype);
1676 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
1677 end if;
1678
1679 -- Now we process the aggregate. Note that we don't use the normal
1680 -- aggregate code for this purpose, because we don't want any of the
1681 -- normal expansion activities, and a number of special semantic
1682 -- rules apply (including the component type being any integer type)
1683
1684 -- Badent signals that we found some incorrect entries processing
1685 -- the list. The final checks for completeness and ordering are
1686 -- skipped in this case.
1687
1688 Elit := First_Literal (Enumtype);
1689
1690 -- First the positional entries if any
1691
1692 if Present (Expressions (Aggr)) then
1693 Expr := First (Expressions (Aggr));
1694 while Present (Expr) loop
1695 if No (Elit) then
1696 Error_Msg_N ("too many entries in aggregate", Expr);
1697 return;
1698 end if;
1699
1700 Val := Static_Integer (Expr);
1701
1702 if Val = No_Uint then
1703 Err := True;
1704
1705 elsif Val < Lo or else Hi < Val then
1706 Error_Msg_N ("value outside permitted range", Expr);
1707 Err := True;
1708 end if;
1709
1710 Set_Enumeration_Rep (Elit, Val);
1711 Set_Enumeration_Rep_Expr (Elit, Expr);
1712 Next (Expr);
1713 Next (Elit);
1714 end loop;
1715 end if;
1716
1717 -- Now process the named entries if present
1718
1719 if Present (Component_Associations (Aggr)) then
1720 Assoc := First (Component_Associations (Aggr));
1721 while Present (Assoc) loop
1722 Choice := First (Choices (Assoc));
1723
1724 if Present (Next (Choice)) then
1725 Error_Msg_N
1726 ("multiple choice not allowed here", Next (Choice));
1727 Err := True;
1728 end if;
1729
1730 if Nkind (Choice) = N_Others_Choice then
1731 Error_Msg_N ("others choice not allowed here", Choice);
1732 Err := True;
1733
1734 elsif Nkind (Choice) = N_Range then
1735 -- ??? should allow zero/one element range here
1736 Error_Msg_N ("range not allowed here", Choice);
1737 Err := True;
1738
1739 else
1740 Analyze_And_Resolve (Choice, Enumtype);
1741
1742 if Is_Entity_Name (Choice)
1743 and then Is_Type (Entity (Choice))
1744 then
1745 Error_Msg_N ("subtype name not allowed here", Choice);
1746 Err := True;
1747 -- ??? should allow static subtype with zero/one entry
1748
1749 elsif Etype (Choice) = Base_Type (Enumtype) then
1750 if not Is_Static_Expression (Choice) then
1751 Flag_Non_Static_Expr
1752 ("non-static expression used for choice!", Choice);
1753 Err := True;
1754
1755 else
1756 Elit := Expr_Value_E (Choice);
1757
1758 if Present (Enumeration_Rep_Expr (Elit)) then
1759 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
1760 Error_Msg_NE
1761 ("representation for& previously given#",
1762 Choice, Elit);
1763 Err := True;
1764 end if;
1765
1766 Set_Enumeration_Rep_Expr (Elit, Choice);
1767
1768 Expr := Expression (Assoc);
1769 Val := Static_Integer (Expr);
1770
1771 if Val = No_Uint then
1772 Err := True;
1773
1774 elsif Val < Lo or else Hi < Val then
1775 Error_Msg_N ("value outside permitted range", Expr);
1776 Err := True;
1777 end if;
1778
1779 Set_Enumeration_Rep (Elit, Val);
1780 end if;
1781 end if;
1782 end if;
1783
1784 Next (Assoc);
1785 end loop;
1786 end if;
1787
1788 -- Aggregate is fully processed. Now we check that a full set of
1789 -- representations was given, and that they are in range and in order.
1790 -- These checks are only done if no other errors occurred.
1791
1792 if not Err then
1793 Min := No_Uint;
1794 Max := No_Uint;
1795
1796 Elit := First_Literal (Enumtype);
1797 while Present (Elit) loop
1798 if No (Enumeration_Rep_Expr (Elit)) then
1799 Error_Msg_NE ("missing representation for&!", N, Elit);
1800
1801 else
1802 Val := Enumeration_Rep (Elit);
1803
1804 if Min = No_Uint then
1805 Min := Val;
1806 end if;
1807
1808 if Val /= No_Uint then
1809 if Max /= No_Uint and then Val <= Max then
1810 Error_Msg_NE
1811 ("enumeration value for& not ordered!",
1812 Enumeration_Rep_Expr (Elit), Elit);
1813 end if;
1814
1815 Max := Val;
1816 end if;
1817
1818 -- If there is at least one literal whose representation
1819 -- is not equal to the Pos value, then note that this
1820 -- enumeration type has a non-standard representation.
1821
1822 if Val /= Enumeration_Pos (Elit) then
1823 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
1824 end if;
1825 end if;
1826
1827 Next (Elit);
1828 end loop;
1829
1830 -- Now set proper size information
1831
1832 declare
1833 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
1834
1835 begin
1836 if Has_Size_Clause (Enumtype) then
1837 if Esize (Enumtype) >= Minsize then
1838 null;
1839
1840 else
1841 Minsize :=
1842 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
1843
1844 if Esize (Enumtype) < Minsize then
1845 Error_Msg_N ("previously given size is too small", N);
1846
1847 else
1848 Set_Has_Biased_Representation (Enumtype);
1849 end if;
1850 end if;
1851
1852 else
1853 Set_RM_Size (Enumtype, Minsize);
1854 Set_Enum_Esize (Enumtype);
1855 end if;
1856
1857 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
1858 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
1859 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
1860 end;
1861 end if;
1862
1863 -- We repeat the too late test in case it froze itself!
1864
1865 if Rep_Item_Too_Late (Enumtype, N) then
1866 null;
1867 end if;
1868 end Analyze_Enumeration_Representation_Clause;
1869
1870 ----------------------------
1871 -- Analyze_Free_Statement --
1872 ----------------------------
1873
1874 procedure Analyze_Free_Statement (N : Node_Id) is
1875 begin
1876 Analyze (Expression (N));
1877 end Analyze_Free_Statement;
1878
1879 ------------------------------------------
1880 -- Analyze_Record_Representation_Clause --
1881 ------------------------------------------
1882
1883 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
1884 Loc : constant Source_Ptr := Sloc (N);
1885 Ident : constant Node_Id := Identifier (N);
1886 Rectype : Entity_Id;
1887 Fent : Entity_Id;
1888 CC : Node_Id;
1889 Posit : Uint;
1890 Fbit : Uint;
1891 Lbit : Uint;
1892 Hbit : Uint := Uint_0;
1893 Comp : Entity_Id;
1894 Ocomp : Entity_Id;
1895 Biased : Boolean;
1896
1897 Max_Bit_So_Far : Uint;
1898 -- Records the maximum bit position so far. If all field positions
1899 -- are monotonically increasing, then we can skip the circuit for
1900 -- checking for overlap, since no overlap is possible.
1901
1902 Overlap_Check_Required : Boolean;
1903 -- Used to keep track of whether or not an overlap check is required
1904
1905 Ccount : Natural := 0;
1906 -- Number of component clauses in record rep clause
1907
1908 begin
1909 Find_Type (Ident);
1910 Rectype := Entity (Ident);
1911
1912 if Rectype = Any_Type
1913 or else Rep_Item_Too_Early (Rectype, N)
1914 then
1915 return;
1916 else
1917 Rectype := Underlying_Type (Rectype);
1918 end if;
1919
1920 -- First some basic error checks
1921
1922 if not Is_Record_Type (Rectype) then
1923 Error_Msg_NE
1924 ("record type required, found}", Ident, First_Subtype (Rectype));
1925 return;
1926
1927 elsif Is_Unchecked_Union (Rectype) then
1928 Error_Msg_N
1929 ("record rep clause not allowed for Unchecked_Union", N);
1930
1931 elsif Scope (Rectype) /= Current_Scope then
1932 Error_Msg_N ("type must be declared in this scope", N);
1933 return;
1934
1935 elsif not Is_First_Subtype (Rectype) then
1936 Error_Msg_N ("cannot give record rep clause for subtype", N);
1937 return;
1938
1939 elsif Has_Record_Rep_Clause (Rectype) then
1940 Error_Msg_N ("duplicate record rep clause ignored", N);
1941 return;
1942
1943 elsif Rep_Item_Too_Late (Rectype, N) then
1944 return;
1945 end if;
1946
1947 if Present (Mod_Clause (N)) then
1948 declare
1949 Loc : constant Source_Ptr := Sloc (N);
1950 M : constant Node_Id := Mod_Clause (N);
1951 P : constant List_Id := Pragmas_Before (M);
1952 AtM_Nod : Node_Id;
1953
1954 Mod_Val : Uint;
1955 pragma Warnings (Off, Mod_Val);
1956
1957 begin
1958 if Warn_On_Obsolescent_Feature then
1959 Error_Msg_N
1960 ("mod clause is an obsolescent feature ('R'M 'J.8)?", N);
1961 Error_Msg_N
1962 ("\use alignment attribute definition clause instead?", N);
1963 end if;
1964
1965 if Present (P) then
1966 Analyze_List (P);
1967 end if;
1968
1969 -- In ASIS_Mode mode, expansion is disabled, but we must
1970 -- convert the Mod clause into an alignment clause anyway, so
1971 -- that the back-end can compute and back-annotate properly the
1972 -- size and alignment of types that may include this record.
1973
1974 if Operating_Mode = Check_Semantics
1975 and then ASIS_Mode
1976 then
1977 AtM_Nod :=
1978 Make_Attribute_Definition_Clause (Loc,
1979 Name => New_Reference_To (Base_Type (Rectype), Loc),
1980 Chars => Name_Alignment,
1981 Expression => Relocate_Node (Expression (M)));
1982
1983 Set_From_At_Mod (AtM_Nod);
1984 Insert_After (N, AtM_Nod);
1985 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
1986 Set_Mod_Clause (N, Empty);
1987
1988 else
1989 -- Get the alignment value to perform error checking
1990
1991 Mod_Val := Get_Alignment_Value (Expression (M));
1992
1993 end if;
1994 end;
1995 end if;
1996
1997 -- Clear any existing component clauses for the type (this happens
1998 -- with derived types, where we are now overriding the original)
1999
2000 Fent := First_Entity (Rectype);
2001
2002 Comp := Fent;
2003 while Present (Comp) loop
2004 if Ekind (Comp) = E_Component
2005 or else Ekind (Comp) = E_Discriminant
2006 then
2007 Set_Component_Clause (Comp, Empty);
2008 end if;
2009
2010 Next_Entity (Comp);
2011 end loop;
2012
2013 -- All done if no component clauses
2014
2015 CC := First (Component_Clauses (N));
2016
2017 if No (CC) then
2018 return;
2019 end if;
2020
2021 -- If a tag is present, then create a component clause that places
2022 -- it at the start of the record (otherwise gigi may place it after
2023 -- other fields that have rep clauses).
2024
2025 if Nkind (Fent) = N_Defining_Identifier
2026 and then Chars (Fent) = Name_uTag
2027 then
2028 Set_Component_Bit_Offset (Fent, Uint_0);
2029 Set_Normalized_Position (Fent, Uint_0);
2030 Set_Normalized_First_Bit (Fent, Uint_0);
2031 Set_Normalized_Position_Max (Fent, Uint_0);
2032 Init_Esize (Fent, System_Address_Size);
2033
2034 Set_Component_Clause (Fent,
2035 Make_Component_Clause (Loc,
2036 Component_Name =>
2037 Make_Identifier (Loc,
2038 Chars => Name_uTag),
2039
2040 Position =>
2041 Make_Integer_Literal (Loc,
2042 Intval => Uint_0),
2043
2044 First_Bit =>
2045 Make_Integer_Literal (Loc,
2046 Intval => Uint_0),
2047
2048 Last_Bit =>
2049 Make_Integer_Literal (Loc,
2050 UI_From_Int (System_Address_Size))));
2051
2052 Ccount := Ccount + 1;
2053 end if;
2054
2055 -- A representation like this applies to the base type
2056
2057 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2058 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2059 Set_Has_Specified_Layout (Base_Type (Rectype));
2060
2061 Max_Bit_So_Far := Uint_Minus_1;
2062 Overlap_Check_Required := False;
2063
2064 -- Process the component clauses
2065
2066 while Present (CC) loop
2067
2068 -- If pragma, just analyze it
2069
2070 if Nkind (CC) = N_Pragma then
2071 Analyze (CC);
2072
2073 -- Processing for real component clause
2074
2075 else
2076 Ccount := Ccount + 1;
2077 Posit := Static_Integer (Position (CC));
2078 Fbit := Static_Integer (First_Bit (CC));
2079 Lbit := Static_Integer (Last_Bit (CC));
2080
2081 if Posit /= No_Uint
2082 and then Fbit /= No_Uint
2083 and then Lbit /= No_Uint
2084 then
2085 if Posit < 0 then
2086 Error_Msg_N
2087 ("position cannot be negative", Position (CC));
2088
2089 elsif Fbit < 0 then
2090 Error_Msg_N
2091 ("first bit cannot be negative", First_Bit (CC));
2092
2093 -- Values look OK, so find the corresponding record component
2094 -- Even though the syntax allows an attribute reference for
2095 -- implementation-defined components, GNAT does not allow the
2096 -- tag to get an explicit position.
2097
2098 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2099 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2100 Error_Msg_N ("position of tag cannot be specified", CC);
2101 else
2102 Error_Msg_N ("illegal component name", CC);
2103 end if;
2104
2105 else
2106 Comp := First_Entity (Rectype);
2107 while Present (Comp) loop
2108 exit when Chars (Comp) = Chars (Component_Name (CC));
2109 Next_Entity (Comp);
2110 end loop;
2111
2112 if No (Comp) then
2113
2114 -- Maybe component of base type that is absent from
2115 -- statically constrained first subtype.
2116
2117 Comp := First_Entity (Base_Type (Rectype));
2118 while Present (Comp) loop
2119 exit when Chars (Comp) = Chars (Component_Name (CC));
2120 Next_Entity (Comp);
2121 end loop;
2122 end if;
2123
2124 if No (Comp) then
2125 Error_Msg_N
2126 ("component clause is for non-existent field", CC);
2127
2128 elsif Present (Component_Clause (Comp)) then
2129 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2130 Error_Msg_N
2131 ("component clause previously given#", CC);
2132
2133 else
2134 -- Update Fbit and Lbit to the actual bit number
2135
2136 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2137 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2138
2139 if Fbit <= Max_Bit_So_Far then
2140 Overlap_Check_Required := True;
2141 else
2142 Max_Bit_So_Far := Lbit;
2143 end if;
2144
2145 if Has_Size_Clause (Rectype)
2146 and then Esize (Rectype) <= Lbit
2147 then
2148 Error_Msg_N
2149 ("bit number out of range of specified size",
2150 Last_Bit (CC));
2151 else
2152 Set_Component_Clause (Comp, CC);
2153 Set_Component_Bit_Offset (Comp, Fbit);
2154 Set_Esize (Comp, 1 + (Lbit - Fbit));
2155 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2156 Set_Normalized_Position (Comp, Fbit / SSU);
2157
2158 Set_Normalized_Position_Max
2159 (Fent, Normalized_Position (Fent));
2160
2161 if Is_Tagged_Type (Rectype)
2162 and then Fbit < System_Address_Size
2163 then
2164 Error_Msg_NE
2165 ("component overlaps tag field of&",
2166 CC, Rectype);
2167 end if;
2168
2169 -- This information is also set in the corresponding
2170 -- component of the base type, found by accessing the
2171 -- Original_Record_Component link if it is present.
2172
2173 Ocomp := Original_Record_Component (Comp);
2174
2175 if Hbit < Lbit then
2176 Hbit := Lbit;
2177 end if;
2178
2179 Check_Size
2180 (Component_Name (CC),
2181 Etype (Comp),
2182 Esize (Comp),
2183 Biased);
2184
2185 Set_Has_Biased_Representation (Comp, Biased);
2186
2187 if Present (Ocomp) then
2188 Set_Component_Clause (Ocomp, CC);
2189 Set_Component_Bit_Offset (Ocomp, Fbit);
2190 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2191 Set_Normalized_Position (Ocomp, Fbit / SSU);
2192 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2193
2194 Set_Normalized_Position_Max
2195 (Ocomp, Normalized_Position (Ocomp));
2196
2197 Set_Has_Biased_Representation
2198 (Ocomp, Has_Biased_Representation (Comp));
2199 end if;
2200
2201 if Esize (Comp) < 0 then
2202 Error_Msg_N ("component size is negative", CC);
2203 end if;
2204 end if;
2205 end if;
2206 end if;
2207 end if;
2208 end if;
2209
2210 Next (CC);
2211 end loop;
2212
2213 -- Now that we have processed all the component clauses, check for
2214 -- overlap. We have to leave this till last, since the components
2215 -- can appear in any arbitrary order in the representation clause.
2216
2217 -- We do not need this check if all specified ranges were monotonic,
2218 -- as recorded by Overlap_Check_Required being False at this stage.
2219
2220 -- This first section checks if there are any overlapping entries
2221 -- at all. It does this by sorting all entries and then seeing if
2222 -- there are any overlaps. If there are none, then that is decisive,
2223 -- but if there are overlaps, they may still be OK (they may result
2224 -- from fields in different variants).
2225
2226 if Overlap_Check_Required then
2227 Overlap_Check1 : declare
2228
2229 OC_Fbit : array (0 .. Ccount) of Uint;
2230 -- First-bit values for component clauses, the value is the
2231 -- offset of the first bit of the field from start of record.
2232 -- The zero entry is for use in sorting.
2233
2234 OC_Lbit : array (0 .. Ccount) of Uint;
2235 -- Last-bit values for component clauses, the value is the
2236 -- offset of the last bit of the field from start of record.
2237 -- The zero entry is for use in sorting.
2238
2239 OC_Count : Natural := 0;
2240 -- Count of entries in OC_Fbit and OC_Lbit
2241
2242 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2243 -- Compare routine for Sort (See GNAT.Heap_Sort_A)
2244
2245 procedure OC_Move (From : Natural; To : Natural);
2246 -- Move routine for Sort (see GNAT.Heap_Sort_A)
2247
2248 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2249 begin
2250 return OC_Fbit (Op1) < OC_Fbit (Op2);
2251 end OC_Lt;
2252
2253 procedure OC_Move (From : Natural; To : Natural) is
2254 begin
2255 OC_Fbit (To) := OC_Fbit (From);
2256 OC_Lbit (To) := OC_Lbit (From);
2257 end OC_Move;
2258
2259 begin
2260 CC := First (Component_Clauses (N));
2261 while Present (CC) loop
2262 if Nkind (CC) /= N_Pragma then
2263 Posit := Static_Integer (Position (CC));
2264 Fbit := Static_Integer (First_Bit (CC));
2265 Lbit := Static_Integer (Last_Bit (CC));
2266
2267 if Posit /= No_Uint
2268 and then Fbit /= No_Uint
2269 and then Lbit /= No_Uint
2270 then
2271 OC_Count := OC_Count + 1;
2272 Posit := Posit * SSU;
2273 OC_Fbit (OC_Count) := Fbit + Posit;
2274 OC_Lbit (OC_Count) := Lbit + Posit;
2275 end if;
2276 end if;
2277
2278 Next (CC);
2279 end loop;
2280
2281 Sort
2282 (OC_Count,
2283 OC_Move'Unrestricted_Access,
2284 OC_Lt'Unrestricted_Access);
2285
2286 Overlap_Check_Required := False;
2287 for J in 1 .. OC_Count - 1 loop
2288 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2289 Overlap_Check_Required := True;
2290 exit;
2291 end if;
2292 end loop;
2293 end Overlap_Check1;
2294 end if;
2295
2296 -- If Overlap_Check_Required is still True, then we have to do
2297 -- the full scale overlap check, since we have at least two fields
2298 -- that do overlap, and we need to know if that is OK since they
2299 -- are in the same variant, or whether we have a definite problem
2300
2301 if Overlap_Check_Required then
2302 Overlap_Check2 : declare
2303 C1_Ent, C2_Ent : Entity_Id;
2304 -- Entities of components being checked for overlap
2305
2306 Clist : Node_Id;
2307 -- Component_List node whose Component_Items are being checked
2308
2309 Citem : Node_Id;
2310 -- Component declaration for component being checked
2311
2312 begin
2313 C1_Ent := First_Entity (Base_Type (Rectype));
2314
2315 -- Loop through all components in record. For each component check
2316 -- for overlap with any of the preceding elements on the component
2317 -- list containing the component, and also, if the component is in
2318 -- a variant, check against components outside the case structure.
2319 -- This latter test is repeated recursively up the variant tree.
2320
2321 Main_Component_Loop : while Present (C1_Ent) loop
2322 if Ekind (C1_Ent) /= E_Component
2323 and then Ekind (C1_Ent) /= E_Discriminant
2324 then
2325 goto Continue_Main_Component_Loop;
2326 end if;
2327
2328 -- Skip overlap check if entity has no declaration node. This
2329 -- happens with discriminants in constrained derived types.
2330 -- Probably we are missing some checks as a result, but that
2331 -- does not seem terribly serious ???
2332
2333 if No (Declaration_Node (C1_Ent)) then
2334 goto Continue_Main_Component_Loop;
2335 end if;
2336
2337 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2338
2339 -- Loop through component lists that need checking. Check the
2340 -- current component list and all lists in variants above us.
2341
2342 Component_List_Loop : loop
2343
2344 -- If derived type definition, go to full declaration
2345 -- If at outer level, check discriminants if there are any
2346
2347 if Nkind (Clist) = N_Derived_Type_Definition then
2348 Clist := Parent (Clist);
2349 end if;
2350
2351 -- Outer level of record definition, check discriminants
2352
2353 if Nkind (Clist) = N_Full_Type_Declaration
2354 or else Nkind (Clist) = N_Private_Type_Declaration
2355 then
2356 if Has_Discriminants (Defining_Identifier (Clist)) then
2357 C2_Ent :=
2358 First_Discriminant (Defining_Identifier (Clist));
2359
2360 while Present (C2_Ent) loop
2361 exit when C1_Ent = C2_Ent;
2362 Check_Component_Overlap (C1_Ent, C2_Ent);
2363 Next_Discriminant (C2_Ent);
2364 end loop;
2365 end if;
2366
2367 -- Record extension case
2368
2369 elsif Nkind (Clist) = N_Derived_Type_Definition then
2370 Clist := Empty;
2371
2372 -- Otherwise check one component list
2373
2374 else
2375 Citem := First (Component_Items (Clist));
2376
2377 while Present (Citem) loop
2378 if Nkind (Citem) = N_Component_Declaration then
2379 C2_Ent := Defining_Identifier (Citem);
2380 exit when C1_Ent = C2_Ent;
2381 Check_Component_Overlap (C1_Ent, C2_Ent);
2382 end if;
2383
2384 Next (Citem);
2385 end loop;
2386 end if;
2387
2388 -- Check for variants above us (the parent of the Clist can
2389 -- be a variant, in which case its parent is a variant part,
2390 -- and the parent of the variant part is a component list
2391 -- whose components must all be checked against the current
2392 -- component for overlap.
2393
2394 if Nkind (Parent (Clist)) = N_Variant then
2395 Clist := Parent (Parent (Parent (Clist)));
2396
2397 -- Check for possible discriminant part in record, this is
2398 -- treated essentially as another level in the recursion.
2399 -- For this case we have the parent of the component list
2400 -- is the record definition, and its parent is the full
2401 -- type declaration which contains the discriminant
2402 -- specifications.
2403
2404 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2405 Clist := Parent (Parent ((Clist)));
2406
2407 -- If neither of these two cases, we are at the top of
2408 -- the tree
2409
2410 else
2411 exit Component_List_Loop;
2412 end if;
2413 end loop Component_List_Loop;
2414
2415 <<Continue_Main_Component_Loop>>
2416 Next_Entity (C1_Ent);
2417
2418 end loop Main_Component_Loop;
2419 end Overlap_Check2;
2420 end if;
2421
2422 -- For records that have component clauses for all components, and
2423 -- whose size is less than or equal to 32, we need to know the size
2424 -- in the front end to activate possible packed array processing
2425 -- where the component type is a record.
2426
2427 -- At this stage Hbit + 1 represents the first unused bit from all
2428 -- the component clauses processed, so if the component clauses are
2429 -- complete, then this is the length of the record.
2430
2431 -- For records longer than System.Storage_Unit, and for those where
2432 -- not all components have component clauses, the back end determines
2433 -- the length (it may for example be appopriate to round up the size
2434 -- to some convenient boundary, based on alignment considerations etc).
2435
2436 if Unknown_RM_Size (Rectype)
2437 and then Hbit + 1 <= 32
2438 then
2439 -- Nothing to do if at least one component with no component clause
2440
2441 Comp := First_Entity (Rectype);
2442 while Present (Comp) loop
2443 if Ekind (Comp) = E_Component
2444 or else Ekind (Comp) = E_Discriminant
2445 then
2446 if No (Component_Clause (Comp)) then
2447 return;
2448 end if;
2449 end if;
2450
2451 Next_Entity (Comp);
2452 end loop;
2453
2454 -- If we fall out of loop, all components have component clauses
2455 -- and so we can set the size to the maximum value.
2456
2457 Set_RM_Size (Rectype, Hbit + 1);
2458 end if;
2459 end Analyze_Record_Representation_Clause;
2460
2461 -----------------------------
2462 -- Check_Component_Overlap --
2463 -----------------------------
2464
2465 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
2466 begin
2467 if Present (Component_Clause (C1_Ent))
2468 and then Present (Component_Clause (C2_Ent))
2469 then
2470 -- Exclude odd case where we have two tag fields in the same
2471 -- record, both at location zero. This seems a bit strange,
2472 -- but it seems to happen in some circumstances ???
2473
2474 if Chars (C1_Ent) = Name_uTag
2475 and then Chars (C2_Ent) = Name_uTag
2476 then
2477 return;
2478 end if;
2479
2480 -- Here we check if the two fields overlap
2481
2482 declare
2483 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
2484 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
2485 E1 : constant Uint := S1 + Esize (C1_Ent);
2486 E2 : constant Uint := S2 + Esize (C2_Ent);
2487
2488 begin
2489 if E2 <= S1 or else E1 <= S2 then
2490 null;
2491 else
2492 Error_Msg_Node_2 :=
2493 Component_Name (Component_Clause (C2_Ent));
2494 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
2495 Error_Msg_Node_1 :=
2496 Component_Name (Component_Clause (C1_Ent));
2497 Error_Msg_N
2498 ("component& overlaps & #",
2499 Component_Name (Component_Clause (C1_Ent)));
2500 end if;
2501 end;
2502 end if;
2503 end Check_Component_Overlap;
2504
2505 -----------------------------------
2506 -- Check_Constant_Address_Clause --
2507 -----------------------------------
2508
2509 procedure Check_Constant_Address_Clause
2510 (Expr : Node_Id;
2511 U_Ent : Entity_Id)
2512 is
2513 procedure Check_At_Constant_Address (Nod : Node_Id);
2514 -- Checks that the given node N represents a name whose 'Address
2515 -- is constant (in the same sense as OK_Constant_Address_Clause,
2516 -- i.e. the address value is the same at the point of declaration
2517 -- of U_Ent and at the time of elaboration of the address clause.
2518
2519 procedure Check_Expr_Constants (Nod : Node_Id);
2520 -- Checks that Nod meets the requirements for a constant address
2521 -- clause in the sense of the enclosing procedure.
2522
2523 procedure Check_List_Constants (Lst : List_Id);
2524 -- Check that all elements of list Lst meet the requirements for a
2525 -- constant address clause in the sense of the enclosing procedure.
2526
2527 -------------------------------
2528 -- Check_At_Constant_Address --
2529 -------------------------------
2530
2531 procedure Check_At_Constant_Address (Nod : Node_Id) is
2532 begin
2533 if Is_Entity_Name (Nod) then
2534 if Present (Address_Clause (Entity ((Nod)))) then
2535 Error_Msg_NE
2536 ("invalid address clause for initialized object &!",
2537 Nod, U_Ent);
2538 Error_Msg_NE
2539 ("address for& cannot" &
2540 " depend on another address clause! ('R'M 13.1(22))!",
2541 Nod, U_Ent);
2542
2543 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
2544 and then Sloc (U_Ent) < Sloc (Entity (Nod))
2545 then
2546 Error_Msg_NE
2547 ("invalid address clause for initialized object &!",
2548 Nod, U_Ent);
2549 Error_Msg_Name_1 := Chars (Entity (Nod));
2550 Error_Msg_Name_2 := Chars (U_Ent);
2551 Error_Msg_N
2552 ("\% must be defined before % ('R'M 13.1(22))!",
2553 Nod);
2554 end if;
2555
2556 elsif Nkind (Nod) = N_Selected_Component then
2557 declare
2558 T : constant Entity_Id := Etype (Prefix (Nod));
2559
2560 begin
2561 if (Is_Record_Type (T)
2562 and then Has_Discriminants (T))
2563 or else
2564 (Is_Access_Type (T)
2565 and then Is_Record_Type (Designated_Type (T))
2566 and then Has_Discriminants (Designated_Type (T)))
2567 then
2568 Error_Msg_NE
2569 ("invalid address clause for initialized object &!",
2570 Nod, U_Ent);
2571 Error_Msg_N
2572 ("\address cannot depend on component" &
2573 " of discriminated record ('R'M 13.1(22))!",
2574 Nod);
2575 else
2576 Check_At_Constant_Address (Prefix (Nod));
2577 end if;
2578 end;
2579
2580 elsif Nkind (Nod) = N_Indexed_Component then
2581 Check_At_Constant_Address (Prefix (Nod));
2582 Check_List_Constants (Expressions (Nod));
2583
2584 else
2585 Check_Expr_Constants (Nod);
2586 end if;
2587 end Check_At_Constant_Address;
2588
2589 --------------------------
2590 -- Check_Expr_Constants --
2591 --------------------------
2592
2593 procedure Check_Expr_Constants (Nod : Node_Id) is
2594 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
2595 Ent : Entity_Id := Empty;
2596
2597 begin
2598 if Nkind (Nod) in N_Has_Etype
2599 and then Etype (Nod) = Any_Type
2600 then
2601 return;
2602 end if;
2603
2604 case Nkind (Nod) is
2605 when N_Empty | N_Error =>
2606 return;
2607
2608 when N_Identifier | N_Expanded_Name =>
2609 Ent := Entity (Nod);
2610
2611 -- We need to look at the original node if it is different
2612 -- from the node, since we may have rewritten things and
2613 -- substituted an identifier representing the rewrite.
2614
2615 if Original_Node (Nod) /= Nod then
2616 Check_Expr_Constants (Original_Node (Nod));
2617
2618 -- If the node is an object declaration without initial
2619 -- value, some code has been expanded, and the expression
2620 -- is not constant, even if the constituents might be
2621 -- acceptable, as in A'Address + offset.
2622
2623 if Ekind (Ent) = E_Variable
2624 and then Nkind (Declaration_Node (Ent))
2625 = N_Object_Declaration
2626 and then
2627 No (Expression (Declaration_Node (Ent)))
2628 then
2629 Error_Msg_NE
2630 ("invalid address clause for initialized object &!",
2631 Nod, U_Ent);
2632
2633 -- If entity is constant, it may be the result of expanding
2634 -- a check. We must verify that its declaration appears
2635 -- before the object in question, else we also reject the
2636 -- address clause.
2637
2638 elsif Ekind (Ent) = E_Constant
2639 and then In_Same_Source_Unit (Ent, U_Ent)
2640 and then Sloc (Ent) > Loc_U_Ent
2641 then
2642 Error_Msg_NE
2643 ("invalid address clause for initialized object &!",
2644 Nod, U_Ent);
2645 end if;
2646
2647 return;
2648 end if;
2649
2650 -- Otherwise look at the identifier and see if it is OK
2651
2652 if Ekind (Ent) = E_Named_Integer
2653 or else
2654 Ekind (Ent) = E_Named_Real
2655 or else
2656 Is_Type (Ent)
2657 then
2658 return;
2659
2660 elsif
2661 Ekind (Ent) = E_Constant
2662 or else
2663 Ekind (Ent) = E_In_Parameter
2664 then
2665 -- This is the case where we must have Ent defined
2666 -- before U_Ent. Clearly if they are in different
2667 -- units this requirement is met since the unit
2668 -- containing Ent is already processed.
2669
2670 if not In_Same_Source_Unit (Ent, U_Ent) then
2671 return;
2672
2673 -- Otherwise location of Ent must be before the
2674 -- location of U_Ent, that's what prior defined means.
2675
2676 elsif Sloc (Ent) < Loc_U_Ent then
2677 return;
2678
2679 else
2680 Error_Msg_NE
2681 ("invalid address clause for initialized object &!",
2682 Nod, U_Ent);
2683 Error_Msg_Name_1 := Chars (Ent);
2684 Error_Msg_Name_2 := Chars (U_Ent);
2685 Error_Msg_N
2686 ("\% must be defined before % ('R'M 13.1(22))!",
2687 Nod);
2688 end if;
2689
2690 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
2691 Check_Expr_Constants (Original_Node (Nod));
2692
2693 else
2694 Error_Msg_NE
2695 ("invalid address clause for initialized object &!",
2696 Nod, U_Ent);
2697
2698 if Comes_From_Source (Ent) then
2699 Error_Msg_Name_1 := Chars (Ent);
2700 Error_Msg_N
2701 ("\reference to variable% not allowed"
2702 & " ('R'M 13.1(22))!", Nod);
2703 else
2704 Error_Msg_N
2705 ("non-static expression not allowed"
2706 & " ('R'M 13.1(22))!", Nod);
2707 end if;
2708 end if;
2709
2710 when N_Integer_Literal =>
2711
2712 -- If this is a rewritten unchecked conversion, in a system
2713 -- where Address is an integer type, always use the base type
2714 -- for a literal value. This is user-friendly and prevents
2715 -- order-of-elaboration issues with instances of unchecked
2716 -- conversion.
2717
2718 if Nkind (Original_Node (Nod)) = N_Function_Call then
2719 Set_Etype (Nod, Base_Type (Etype (Nod)));
2720 end if;
2721
2722 when N_Real_Literal |
2723 N_String_Literal |
2724 N_Character_Literal =>
2725 return;
2726
2727 when N_Range =>
2728 Check_Expr_Constants (Low_Bound (Nod));
2729 Check_Expr_Constants (High_Bound (Nod));
2730
2731 when N_Explicit_Dereference =>
2732 Check_Expr_Constants (Prefix (Nod));
2733
2734 when N_Indexed_Component =>
2735 Check_Expr_Constants (Prefix (Nod));
2736 Check_List_Constants (Expressions (Nod));
2737
2738 when N_Slice =>
2739 Check_Expr_Constants (Prefix (Nod));
2740 Check_Expr_Constants (Discrete_Range (Nod));
2741
2742 when N_Selected_Component =>
2743 Check_Expr_Constants (Prefix (Nod));
2744
2745 when N_Attribute_Reference =>
2746
2747 if Attribute_Name (Nod) = Name_Address
2748 or else
2749 Attribute_Name (Nod) = Name_Access
2750 or else
2751 Attribute_Name (Nod) = Name_Unchecked_Access
2752 or else
2753 Attribute_Name (Nod) = Name_Unrestricted_Access
2754 then
2755 Check_At_Constant_Address (Prefix (Nod));
2756
2757 else
2758 Check_Expr_Constants (Prefix (Nod));
2759 Check_List_Constants (Expressions (Nod));
2760 end if;
2761
2762 when N_Aggregate =>
2763 Check_List_Constants (Component_Associations (Nod));
2764 Check_List_Constants (Expressions (Nod));
2765
2766 when N_Component_Association =>
2767 Check_Expr_Constants (Expression (Nod));
2768
2769 when N_Extension_Aggregate =>
2770 Check_Expr_Constants (Ancestor_Part (Nod));
2771 Check_List_Constants (Component_Associations (Nod));
2772 Check_List_Constants (Expressions (Nod));
2773
2774 when N_Null =>
2775 return;
2776
2777 when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In =>
2778 Check_Expr_Constants (Left_Opnd (Nod));
2779 Check_Expr_Constants (Right_Opnd (Nod));
2780
2781 when N_Unary_Op =>
2782 Check_Expr_Constants (Right_Opnd (Nod));
2783
2784 when N_Type_Conversion |
2785 N_Qualified_Expression |
2786 N_Allocator =>
2787 Check_Expr_Constants (Expression (Nod));
2788
2789 when N_Unchecked_Type_Conversion =>
2790 Check_Expr_Constants (Expression (Nod));
2791
2792 -- If this is a rewritten unchecked conversion, subtypes
2793 -- in this node are those created within the instance.
2794 -- To avoid order of elaboration issues, replace them
2795 -- with their base types. Note that address clauses can
2796 -- cause order of elaboration problems because they are
2797 -- elaborated by the back-end at the point of definition,
2798 -- and may mention entities declared in between (as long
2799 -- as everything is static). It is user-friendly to allow
2800 -- unchecked conversions in this context.
2801
2802 if Nkind (Original_Node (Nod)) = N_Function_Call then
2803 Set_Etype (Expression (Nod),
2804 Base_Type (Etype (Expression (Nod))));
2805 Set_Etype (Nod, Base_Type (Etype (Nod)));
2806 end if;
2807
2808 when N_Function_Call =>
2809 if not Is_Pure (Entity (Name (Nod))) then
2810 Error_Msg_NE
2811 ("invalid address clause for initialized object &!",
2812 Nod, U_Ent);
2813
2814 Error_Msg_NE
2815 ("\function & is not pure ('R'M 13.1(22))!",
2816 Nod, Entity (Name (Nod)));
2817
2818 else
2819 Check_List_Constants (Parameter_Associations (Nod));
2820 end if;
2821
2822 when N_Parameter_Association =>
2823 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
2824
2825 when others =>
2826 Error_Msg_NE
2827 ("invalid address clause for initialized object &!",
2828 Nod, U_Ent);
2829 Error_Msg_NE
2830 ("\must be constant defined before& ('R'M 13.1(22))!",
2831 Nod, U_Ent);
2832 end case;
2833 end Check_Expr_Constants;
2834
2835 --------------------------
2836 -- Check_List_Constants --
2837 --------------------------
2838
2839 procedure Check_List_Constants (Lst : List_Id) is
2840 Nod1 : Node_Id;
2841
2842 begin
2843 if Present (Lst) then
2844 Nod1 := First (Lst);
2845 while Present (Nod1) loop
2846 Check_Expr_Constants (Nod1);
2847 Next (Nod1);
2848 end loop;
2849 end if;
2850 end Check_List_Constants;
2851
2852 -- Start of processing for Check_Constant_Address_Clause
2853
2854 begin
2855 Check_Expr_Constants (Expr);
2856 end Check_Constant_Address_Clause;
2857
2858 ----------------
2859 -- Check_Size --
2860 ----------------
2861
2862 procedure Check_Size
2863 (N : Node_Id;
2864 T : Entity_Id;
2865 Siz : Uint;
2866 Biased : out Boolean)
2867 is
2868 UT : constant Entity_Id := Underlying_Type (T);
2869 M : Uint;
2870
2871 begin
2872 Biased := False;
2873
2874 -- Dismiss cases for generic types or types with previous errors
2875
2876 if No (UT)
2877 or else UT = Any_Type
2878 or else Is_Generic_Type (UT)
2879 or else Is_Generic_Type (Root_Type (UT))
2880 then
2881 return;
2882
2883 -- Check case of bit packed array
2884
2885 elsif Is_Array_Type (UT)
2886 and then Known_Static_Component_Size (UT)
2887 and then Is_Bit_Packed_Array (UT)
2888 then
2889 declare
2890 Asiz : Uint;
2891 Indx : Node_Id;
2892 Ityp : Entity_Id;
2893
2894 begin
2895 Asiz := Component_Size (UT);
2896 Indx := First_Index (UT);
2897 loop
2898 Ityp := Etype (Indx);
2899
2900 -- If non-static bound, then we are not in the business of
2901 -- trying to check the length, and indeed an error will be
2902 -- issued elsewhere, since sizes of non-static array types
2903 -- cannot be set implicitly or explicitly.
2904
2905 if not Is_Static_Subtype (Ityp) then
2906 return;
2907 end if;
2908
2909 -- Otherwise accumulate next dimension
2910
2911 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
2912 Expr_Value (Type_Low_Bound (Ityp)) +
2913 Uint_1);
2914
2915 Next_Index (Indx);
2916 exit when No (Indx);
2917 end loop;
2918
2919 if Asiz <= Siz then
2920 return;
2921 else
2922 Error_Msg_Uint_1 := Asiz;
2923 Error_Msg_NE
2924 ("size for& too small, minimum allowed is ^", N, T);
2925 Set_Esize (T, Asiz);
2926 Set_RM_Size (T, Asiz);
2927 end if;
2928 end;
2929
2930 -- All other composite types are ignored
2931
2932 elsif Is_Composite_Type (UT) then
2933 return;
2934
2935 -- For fixed-point types, don't check minimum if type is not frozen,
2936 -- since we don't know all the characteristics of the type that can
2937 -- affect the size (e.g. a specified small) till freeze time.
2938
2939 elsif Is_Fixed_Point_Type (UT)
2940 and then not Is_Frozen (UT)
2941 then
2942 null;
2943
2944 -- Cases for which a minimum check is required
2945
2946 else
2947 -- Ignore if specified size is correct for the type
2948
2949 if Known_Esize (UT) and then Siz = Esize (UT) then
2950 return;
2951 end if;
2952
2953 -- Otherwise get minimum size
2954
2955 M := UI_From_Int (Minimum_Size (UT));
2956
2957 if Siz < M then
2958
2959 -- Size is less than minimum size, but one possibility remains
2960 -- that we can manage with the new size if we bias the type
2961
2962 M := UI_From_Int (Minimum_Size (UT, Biased => True));
2963
2964 if Siz < M then
2965 Error_Msg_Uint_1 := M;
2966 Error_Msg_NE
2967 ("size for& too small, minimum allowed is ^", N, T);
2968 Set_Esize (T, M);
2969 Set_RM_Size (T, M);
2970 else
2971 Biased := True;
2972 end if;
2973 end if;
2974 end if;
2975 end Check_Size;
2976
2977 -------------------------
2978 -- Get_Alignment_Value --
2979 -------------------------
2980
2981 function Get_Alignment_Value (Expr : Node_Id) return Uint is
2982 Align : constant Uint := Static_Integer (Expr);
2983
2984 begin
2985 if Align = No_Uint then
2986 return No_Uint;
2987
2988 elsif Align <= 0 then
2989 Error_Msg_N ("alignment value must be positive", Expr);
2990 return No_Uint;
2991
2992 else
2993 for J in Int range 0 .. 64 loop
2994 declare
2995 M : constant Uint := Uint_2 ** J;
2996
2997 begin
2998 exit when M = Align;
2999
3000 if M > Align then
3001 Error_Msg_N
3002 ("alignment value must be power of 2", Expr);
3003 return No_Uint;
3004 end if;
3005 end;
3006 end loop;
3007
3008 return Align;
3009 end if;
3010 end Get_Alignment_Value;
3011
3012 ----------------
3013 -- Initialize --
3014 ----------------
3015
3016 procedure Initialize is
3017 begin
3018 Unchecked_Conversions.Init;
3019 end Initialize;
3020
3021 -------------------------
3022 -- Is_Operational_Item --
3023 -------------------------
3024
3025 function Is_Operational_Item (N : Node_Id) return Boolean is
3026 begin
3027 if Nkind (N) /= N_Attribute_Definition_Clause then
3028 return False;
3029 else
3030 declare
3031 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3032
3033 begin
3034 return Id = Attribute_Input
3035 or else Id = Attribute_Output
3036 or else Id = Attribute_Read
3037 or else Id = Attribute_Write
3038 or else Id = Attribute_External_Tag;
3039 end;
3040 end if;
3041 end Is_Operational_Item;
3042
3043 --------------------------------------
3044 -- Mark_Aliased_Address_As_Volatile --
3045 --------------------------------------
3046
3047 procedure Mark_Aliased_Address_As_Volatile (N : Node_Id) is
3048 Ent : constant Entity_Id := Address_Aliased_Entity (N);
3049
3050 begin
3051 if Present (Ent) then
3052 Set_Treat_As_Volatile (Ent);
3053 end if;
3054 end Mark_Aliased_Address_As_Volatile;
3055
3056 ------------------
3057 -- Minimum_Size --
3058 ------------------
3059
3060 function Minimum_Size
3061 (T : Entity_Id;
3062 Biased : Boolean := False) return Nat
3063 is
3064 Lo : Uint := No_Uint;
3065 Hi : Uint := No_Uint;
3066 LoR : Ureal := No_Ureal;
3067 HiR : Ureal := No_Ureal;
3068 LoSet : Boolean := False;
3069 HiSet : Boolean := False;
3070 B : Uint;
3071 S : Nat;
3072 Ancest : Entity_Id;
3073 R_Typ : constant Entity_Id := Root_Type (T);
3074
3075 begin
3076 -- If bad type, return 0
3077
3078 if T = Any_Type then
3079 return 0;
3080
3081 -- For generic types, just return zero. There cannot be any legitimate
3082 -- need to know such a size, but this routine may be called with a
3083 -- generic type as part of normal processing.
3084
3085 elsif Is_Generic_Type (R_Typ)
3086 or else R_Typ = Any_Type
3087 then
3088 return 0;
3089
3090 -- Access types. Normally an access type cannot have a size smaller
3091 -- than the size of System.Address. The exception is on VMS, where
3092 -- we have short and long addresses, and it is possible for an access
3093 -- type to have a short address size (and thus be less than the size
3094 -- of System.Address itself). We simply skip the check for VMS, and
3095 -- leave the back end to do the check.
3096
3097 elsif Is_Access_Type (T) then
3098 if OpenVMS_On_Target then
3099 return 0;
3100 else
3101 return System_Address_Size;
3102 end if;
3103
3104 -- Floating-point types
3105
3106 elsif Is_Floating_Point_Type (T) then
3107 return UI_To_Int (Esize (R_Typ));
3108
3109 -- Discrete types
3110
3111 elsif Is_Discrete_Type (T) then
3112
3113 -- The following loop is looking for the nearest compile time
3114 -- known bounds following the ancestor subtype chain. The idea
3115 -- is to find the most restrictive known bounds information.
3116
3117 Ancest := T;
3118 loop
3119 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3120 return 0;
3121 end if;
3122
3123 if not LoSet then
3124 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3125 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3126 LoSet := True;
3127 exit when HiSet;
3128 end if;
3129 end if;
3130
3131 if not HiSet then
3132 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3133 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3134 HiSet := True;
3135 exit when LoSet;
3136 end if;
3137 end if;
3138
3139 Ancest := Ancestor_Subtype (Ancest);
3140
3141 if No (Ancest) then
3142 Ancest := Base_Type (T);
3143
3144 if Is_Generic_Type (Ancest) then
3145 return 0;
3146 end if;
3147 end if;
3148 end loop;
3149
3150 -- Fixed-point types. We can't simply use Expr_Value to get the
3151 -- Corresponding_Integer_Value values of the bounds, since these
3152 -- do not get set till the type is frozen, and this routine can
3153 -- be called before the type is frozen. Similarly the test for
3154 -- bounds being static needs to include the case where we have
3155 -- unanalyzed real literals for the same reason.
3156
3157 elsif Is_Fixed_Point_Type (T) then
3158
3159 -- The following loop is looking for the nearest compile time
3160 -- known bounds following the ancestor subtype chain. The idea
3161 -- is to find the most restrictive known bounds information.
3162
3163 Ancest := T;
3164 loop
3165 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3166 return 0;
3167 end if;
3168
3169 if not LoSet then
3170 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3171 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3172 then
3173 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3174 LoSet := True;
3175 exit when HiSet;
3176 end if;
3177 end if;
3178
3179 if not HiSet then
3180 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3181 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3182 then
3183 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3184 HiSet := True;
3185 exit when LoSet;
3186 end if;
3187 end if;
3188
3189 Ancest := Ancestor_Subtype (Ancest);
3190
3191 if No (Ancest) then
3192 Ancest := Base_Type (T);
3193
3194 if Is_Generic_Type (Ancest) then
3195 return 0;
3196 end if;
3197 end if;
3198 end loop;
3199
3200 Lo := UR_To_Uint (LoR / Small_Value (T));
3201 Hi := UR_To_Uint (HiR / Small_Value (T));
3202
3203 -- No other types allowed
3204
3205 else
3206 raise Program_Error;
3207 end if;
3208
3209 -- Fall through with Hi and Lo set. Deal with biased case
3210
3211 if (Biased and then not Is_Fixed_Point_Type (T))
3212 or else Has_Biased_Representation (T)
3213 then
3214 Hi := Hi - Lo;
3215 Lo := Uint_0;
3216 end if;
3217
3218 -- Signed case. Note that we consider types like range 1 .. -1 to be
3219 -- signed for the purpose of computing the size, since the bounds
3220 -- have to be accomodated in the base type.
3221
3222 if Lo < 0 or else Hi < 0 then
3223 S := 1;
3224 B := Uint_1;
3225
3226 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3227 -- Note that we accommodate the case where the bounds cross. This
3228 -- can happen either because of the way the bounds are declared
3229 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3230
3231 while Lo < -B
3232 or else Hi < -B
3233 or else Lo >= B
3234 or else Hi >= B
3235 loop
3236 B := Uint_2 ** S;
3237 S := S + 1;
3238 end loop;
3239
3240 -- Unsigned case
3241
3242 else
3243 -- If both bounds are positive, make sure that both are represen-
3244 -- table in the case where the bounds are crossed. This can happen
3245 -- either because of the way the bounds are declared, or because of
3246 -- the algorithm in Freeze_Fixed_Point_Type.
3247
3248 if Lo > Hi then
3249 Hi := Lo;
3250 end if;
3251
3252 -- S = size, (can accommodate 0 .. (2**size - 1))
3253
3254 S := 0;
3255 while Hi >= Uint_2 ** S loop
3256 S := S + 1;
3257 end loop;
3258 end if;
3259
3260 return S;
3261 end Minimum_Size;
3262
3263 -------------------------
3264 -- New_Stream_Function --
3265 -------------------------
3266
3267 procedure New_Stream_Function
3268 (N : Node_Id;
3269 Ent : Entity_Id;
3270 Subp : Entity_Id;
3271 Nam : TSS_Name_Type)
3272 is
3273 Loc : constant Source_Ptr := Sloc (N);
3274 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3275 Subp_Id : Entity_Id;
3276 Subp_Decl : Node_Id;
3277 F : Entity_Id;
3278 Etyp : Entity_Id;
3279
3280 function Build_Spec return Node_Id;
3281 -- Used for declaration and renaming declaration, so that this is
3282 -- treated as a renaming_as_body.
3283
3284 ----------------
3285 -- Build_Spec --
3286 ----------------
3287
3288 function Build_Spec return Node_Id is
3289 begin
3290 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3291
3292 return
3293 Make_Function_Specification (Loc,
3294 Defining_Unit_Name => Subp_Id,
3295 Parameter_Specifications =>
3296 New_List (
3297 Make_Parameter_Specification (Loc,
3298 Defining_Identifier =>
3299 Make_Defining_Identifier (Loc, Name_S),
3300 Parameter_Type =>
3301 Make_Access_Definition (Loc,
3302 Subtype_Mark =>
3303 New_Reference_To (
3304 Designated_Type (Etype (F)), Loc)))),
3305
3306 Subtype_Mark =>
3307 New_Reference_To (Etyp, Loc));
3308 end Build_Spec;
3309
3310 -- Start of processing for New_Stream_Function
3311
3312 begin
3313 F := First_Formal (Subp);
3314 Etyp := Etype (Subp);
3315
3316 if not Is_Tagged_Type (Ent) then
3317 Subp_Decl :=
3318 Make_Subprogram_Declaration (Loc,
3319 Specification => Build_Spec);
3320 Insert_Action (N, Subp_Decl);
3321 end if;
3322
3323 Subp_Decl :=
3324 Make_Subprogram_Renaming_Declaration (Loc,
3325 Specification => Build_Spec,
3326 Name => New_Reference_To (Subp, Loc));
3327
3328 if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then
3329 Set_TSS (Base_Type (Ent), Subp_Id);
3330 else
3331 Insert_Action (N, Subp_Decl);
3332 Copy_TSS (Subp_Id, Base_Type (Ent));
3333 end if;
3334 end New_Stream_Function;
3335
3336 --------------------------
3337 -- New_Stream_Procedure --
3338 --------------------------
3339
3340 procedure New_Stream_Procedure
3341 (N : Node_Id;
3342 Ent : Entity_Id;
3343 Subp : Entity_Id;
3344 Nam : TSS_Name_Type;
3345 Out_P : Boolean := False)
3346 is
3347 Loc : constant Source_Ptr := Sloc (N);
3348 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3349 Subp_Id : Entity_Id;
3350 Subp_Decl : Node_Id;
3351 F : Entity_Id;
3352 Etyp : Entity_Id;
3353
3354 function Build_Spec return Node_Id;
3355 -- Used for declaration and renaming declaration, so that this is
3356 -- treated as a renaming_as_body.
3357
3358 ----------------
3359 -- Build_Spec --
3360 ----------------
3361
3362 function Build_Spec return Node_Id is
3363 begin
3364 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3365
3366 return
3367 Make_Procedure_Specification (Loc,
3368 Defining_Unit_Name => Subp_Id,
3369 Parameter_Specifications =>
3370 New_List (
3371 Make_Parameter_Specification (Loc,
3372 Defining_Identifier =>
3373 Make_Defining_Identifier (Loc, Name_S),
3374 Parameter_Type =>
3375 Make_Access_Definition (Loc,
3376 Subtype_Mark =>
3377 New_Reference_To (
3378 Designated_Type (Etype (F)), Loc))),
3379
3380 Make_Parameter_Specification (Loc,
3381 Defining_Identifier =>
3382 Make_Defining_Identifier (Loc, Name_V),
3383 Out_Present => Out_P,
3384 Parameter_Type =>
3385 New_Reference_To (Etyp, Loc))));
3386 end Build_Spec;
3387
3388 -- Start of processing for New_Stream_Procedure
3389
3390 begin
3391 F := First_Formal (Subp);
3392 Etyp := Etype (Next_Formal (F));
3393
3394 if not Is_Tagged_Type (Ent) then
3395 Subp_Decl :=
3396 Make_Subprogram_Declaration (Loc,
3397 Specification => Build_Spec);
3398 Insert_Action (N, Subp_Decl);
3399 end if;
3400
3401 Subp_Decl :=
3402 Make_Subprogram_Renaming_Declaration (Loc,
3403 Specification => Build_Spec,
3404 Name => New_Reference_To (Subp, Loc));
3405
3406 if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then
3407 Set_TSS (Base_Type (Ent), Subp_Id);
3408 else
3409 Insert_Action (N, Subp_Decl);
3410 Copy_TSS (Subp_Id, Base_Type (Ent));
3411 end if;
3412 end New_Stream_Procedure;
3413
3414 ------------------------
3415 -- Rep_Item_Too_Early --
3416 ------------------------
3417
3418 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3419 begin
3420 -- Cannot apply rep items that are not operational items
3421 -- to generic types
3422
3423 if Is_Operational_Item (N) then
3424 return False;
3425
3426 elsif Is_Type (T)
3427 and then Is_Generic_Type (Root_Type (T))
3428 then
3429 Error_Msg_N
3430 ("representation item not allowed for generic type", N);
3431 return True;
3432 end if;
3433
3434 -- Otherwise check for incompleted type
3435
3436 if Is_Incomplete_Or_Private_Type (T)
3437 and then No (Underlying_Type (T))
3438 then
3439 Error_Msg_N
3440 ("representation item must be after full type declaration", N);
3441 return True;
3442
3443 -- If the type has incompleted components, a representation clause is
3444 -- illegal but stream attributes and Convention pragmas are correct.
3445
3446 elsif Has_Private_Component (T) then
3447 if Nkind (N) = N_Pragma then
3448 return False;
3449 else
3450 Error_Msg_N
3451 ("representation item must appear after type is fully defined",
3452 N);
3453 return True;
3454 end if;
3455 else
3456 return False;
3457 end if;
3458 end Rep_Item_Too_Early;
3459
3460 -----------------------
3461 -- Rep_Item_Too_Late --
3462 -----------------------
3463
3464 function Rep_Item_Too_Late
3465 (T : Entity_Id;
3466 N : Node_Id;
3467 FOnly : Boolean := False) return Boolean
3468 is
3469 S : Entity_Id;
3470 Parent_Type : Entity_Id;
3471
3472 procedure Too_Late;
3473 -- Output the too late message. Note that this is not considered a
3474 -- serious error, since the effect is simply that we ignore the
3475 -- representation clause in this case.
3476
3477 --------------
3478 -- Too_Late --
3479 --------------
3480
3481 procedure Too_Late is
3482 begin
3483 Error_Msg_N ("|representation item appears too late!", N);
3484 end Too_Late;
3485
3486 -- Start of processing for Rep_Item_Too_Late
3487
3488 begin
3489 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
3490 -- types, which may be frozen if they appear in a representation clause
3491 -- for a local type.
3492
3493 if Is_Frozen (T)
3494 and then not From_With_Type (T)
3495 then
3496 Too_Late;
3497 S := First_Subtype (T);
3498
3499 if Present (Freeze_Node (S)) then
3500 Error_Msg_NE
3501 ("?no more representation items for }!", Freeze_Node (S), S);
3502 end if;
3503
3504 return True;
3505
3506 -- Check for case of non-tagged derived type whose parent either has
3507 -- primitive operations, or is a by reference type (RM 13.1(10)).
3508
3509 elsif Is_Type (T)
3510 and then not FOnly
3511 and then Is_Derived_Type (T)
3512 and then not Is_Tagged_Type (T)
3513 then
3514 Parent_Type := Etype (Base_Type (T));
3515
3516 if Has_Primitive_Operations (Parent_Type) then
3517 Too_Late;
3518 Error_Msg_NE
3519 ("primitive operations already defined for&!", N, Parent_Type);
3520 return True;
3521
3522 elsif Is_By_Reference_Type (Parent_Type) then
3523 Too_Late;
3524 Error_Msg_NE
3525 ("parent type & is a by reference type!", N, Parent_Type);
3526 return True;
3527 end if;
3528 end if;
3529
3530 -- No error, link item into head of chain of rep items for the entity
3531
3532 Record_Rep_Item (T, N);
3533 return False;
3534 end Rep_Item_Too_Late;
3535
3536 -------------------------
3537 -- Same_Representation --
3538 -------------------------
3539
3540 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
3541 T1 : constant Entity_Id := Underlying_Type (Typ1);
3542 T2 : constant Entity_Id := Underlying_Type (Typ2);
3543
3544 begin
3545 -- A quick check, if base types are the same, then we definitely have
3546 -- the same representation, because the subtype specific representation
3547 -- attributes (Size and Alignment) do not affect representation from
3548 -- the point of view of this test.
3549
3550 if Base_Type (T1) = Base_Type (T2) then
3551 return True;
3552
3553 elsif Is_Private_Type (Base_Type (T2))
3554 and then Base_Type (T1) = Full_View (Base_Type (T2))
3555 then
3556 return True;
3557 end if;
3558
3559 -- Tagged types never have differing representations
3560
3561 if Is_Tagged_Type (T1) then
3562 return True;
3563 end if;
3564
3565 -- Representations are definitely different if conventions differ
3566
3567 if Convention (T1) /= Convention (T2) then
3568 return False;
3569 end if;
3570
3571 -- Representations are different if component alignments differ
3572
3573 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
3574 and then
3575 (Is_Record_Type (T2) or else Is_Array_Type (T2))
3576 and then Component_Alignment (T1) /= Component_Alignment (T2)
3577 then
3578 return False;
3579 end if;
3580
3581 -- For arrays, the only real issue is component size. If we know the
3582 -- component size for both arrays, and it is the same, then that's
3583 -- good enough to know we don't have a change of representation.
3584
3585 if Is_Array_Type (T1) then
3586 if Known_Component_Size (T1)
3587 and then Known_Component_Size (T2)
3588 and then Component_Size (T1) = Component_Size (T2)
3589 then
3590 return True;
3591 end if;
3592 end if;
3593
3594 -- Types definitely have same representation if neither has non-standard
3595 -- representation since default representations are always consistent.
3596 -- If only one has non-standard representation, and the other does not,
3597 -- then we consider that they do not have the same representation. They
3598 -- might, but there is no way of telling early enough.
3599
3600 if Has_Non_Standard_Rep (T1) then
3601 if not Has_Non_Standard_Rep (T2) then
3602 return False;
3603 end if;
3604 else
3605 return not Has_Non_Standard_Rep (T2);
3606 end if;
3607
3608 -- Here the two types both have non-standard representation, and we
3609 -- need to determine if they have the same non-standard representation
3610
3611 -- For arrays, we simply need to test if the component sizes are the
3612 -- same. Pragma Pack is reflected in modified component sizes, so this
3613 -- check also deals with pragma Pack.
3614
3615 if Is_Array_Type (T1) then
3616 return Component_Size (T1) = Component_Size (T2);
3617
3618 -- Tagged types always have the same representation, because it is not
3619 -- possible to specify different representations for common fields.
3620
3621 elsif Is_Tagged_Type (T1) then
3622 return True;
3623
3624 -- Case of record types
3625
3626 elsif Is_Record_Type (T1) then
3627
3628 -- Packed status must conform
3629
3630 if Is_Packed (T1) /= Is_Packed (T2) then
3631 return False;
3632
3633 -- Otherwise we must check components. Typ2 maybe a constrained
3634 -- subtype with fewer components, so we compare the components
3635 -- of the base types.
3636
3637 else
3638 Record_Case : declare
3639 CD1, CD2 : Entity_Id;
3640
3641 function Same_Rep return Boolean;
3642 -- CD1 and CD2 are either components or discriminants. This
3643 -- function tests whether the two have the same representation
3644
3645 --------------
3646 -- Same_Rep --
3647 --------------
3648
3649 function Same_Rep return Boolean is
3650 begin
3651 if No (Component_Clause (CD1)) then
3652 return No (Component_Clause (CD2));
3653
3654 else
3655 return
3656 Present (Component_Clause (CD2))
3657 and then
3658 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
3659 and then
3660 Esize (CD1) = Esize (CD2);
3661 end if;
3662 end Same_Rep;
3663
3664 -- Start processing for Record_Case
3665
3666 begin
3667 if Has_Discriminants (T1) then
3668 CD1 := First_Discriminant (T1);
3669 CD2 := First_Discriminant (T2);
3670
3671 -- The number of discriminants may be different if the
3672 -- derived type has fewer (constrained by values). The
3673 -- invisible discriminants retain the representation of
3674 -- the original, so the discrepancy does not per se
3675 -- indicate a different representation.
3676
3677 while Present (CD1)
3678 and then Present (CD2)
3679 loop
3680 if not Same_Rep then
3681 return False;
3682 else
3683 Next_Discriminant (CD1);
3684 Next_Discriminant (CD2);
3685 end if;
3686 end loop;
3687 end if;
3688
3689 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
3690 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
3691
3692 while Present (CD1) loop
3693 if not Same_Rep then
3694 return False;
3695 else
3696 Next_Component (CD1);
3697 Next_Component (CD2);
3698 end if;
3699 end loop;
3700
3701 return True;
3702 end Record_Case;
3703 end if;
3704
3705 -- For enumeration types, we must check each literal to see if the
3706 -- representation is the same. Note that we do not permit enumeration
3707 -- reprsentation clauses for Character and Wide_Character, so these
3708 -- cases were already dealt with.
3709
3710 elsif Is_Enumeration_Type (T1) then
3711
3712 Enumeration_Case : declare
3713 L1, L2 : Entity_Id;
3714
3715 begin
3716 L1 := First_Literal (T1);
3717 L2 := First_Literal (T2);
3718
3719 while Present (L1) loop
3720 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
3721 return False;
3722 else
3723 Next_Literal (L1);
3724 Next_Literal (L2);
3725 end if;
3726 end loop;
3727
3728 return True;
3729
3730 end Enumeration_Case;
3731
3732 -- Any other types have the same representation for these purposes
3733
3734 else
3735 return True;
3736 end if;
3737 end Same_Representation;
3738
3739 --------------------
3740 -- Set_Enum_Esize --
3741 --------------------
3742
3743 procedure Set_Enum_Esize (T : Entity_Id) is
3744 Lo : Uint;
3745 Hi : Uint;
3746 Sz : Nat;
3747
3748 begin
3749 Init_Alignment (T);
3750
3751 -- Find the minimum standard size (8,16,32,64) that fits
3752
3753 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
3754 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
3755
3756 if Lo < 0 then
3757 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
3758 Sz := Standard_Character_Size; -- May be > 8 on some targets
3759
3760 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
3761 Sz := 16;
3762
3763 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
3764 Sz := 32;
3765
3766 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
3767 Sz := 64;
3768 end if;
3769
3770 else
3771 if Hi < Uint_2**08 then
3772 Sz := Standard_Character_Size; -- May be > 8 on some targets
3773
3774 elsif Hi < Uint_2**16 then
3775 Sz := 16;
3776
3777 elsif Hi < Uint_2**32 then
3778 Sz := 32;
3779
3780 else pragma Assert (Hi < Uint_2**63);
3781 Sz := 64;
3782 end if;
3783 end if;
3784
3785 -- That minimum is the proper size unless we have a foreign convention
3786 -- and the size required is 32 or less, in which case we bump the size
3787 -- up to 32. This is required for C and C++ and seems reasonable for
3788 -- all other foreign conventions.
3789
3790 if Has_Foreign_Convention (T)
3791 and then Esize (T) < Standard_Integer_Size
3792 then
3793 Init_Esize (T, Standard_Integer_Size);
3794
3795 else
3796 Init_Esize (T, Sz);
3797 end if;
3798 end Set_Enum_Esize;
3799
3800 -----------------------------------
3801 -- Validate_Unchecked_Conversion --
3802 -----------------------------------
3803
3804 procedure Validate_Unchecked_Conversion
3805 (N : Node_Id;
3806 Act_Unit : Entity_Id)
3807 is
3808 Source : Entity_Id;
3809 Target : Entity_Id;
3810 Vnode : Node_Id;
3811
3812 begin
3813 -- Obtain source and target types. Note that we call Ancestor_Subtype
3814 -- here because the processing for generic instantiation always makes
3815 -- subtypes, and we want the original frozen actual types.
3816
3817 -- If we are dealing with private types, then do the check on their
3818 -- fully declared counterparts if the full declarations have been
3819 -- encountered (they don't have to be visible, but they must exist!)
3820
3821 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
3822
3823 if Is_Private_Type (Source)
3824 and then Present (Underlying_Type (Source))
3825 then
3826 Source := Underlying_Type (Source);
3827 end if;
3828
3829 Target := Ancestor_Subtype (Etype (Act_Unit));
3830
3831 -- If either type is generic, the instantiation happens within a
3832 -- generic unit, and there is nothing to check. The proper check
3833 -- will happen when the enclosing generic is instantiated.
3834
3835 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
3836 return;
3837 end if;
3838
3839 if Is_Private_Type (Target)
3840 and then Present (Underlying_Type (Target))
3841 then
3842 Target := Underlying_Type (Target);
3843 end if;
3844
3845 -- Source may be unconstrained array, but not target
3846
3847 if Is_Array_Type (Target)
3848 and then not Is_Constrained (Target)
3849 then
3850 Error_Msg_N
3851 ("unchecked conversion to unconstrained array not allowed", N);
3852 return;
3853 end if;
3854
3855 -- Make entry in unchecked conversion table for later processing
3856 -- by Validate_Unchecked_Conversions, which will check sizes and
3857 -- alignments (using values set by the back-end where possible).
3858 -- This is only done if the appropriate warning is active
3859
3860 if Warn_On_Unchecked_Conversion then
3861 Unchecked_Conversions.Append
3862 (New_Val => UC_Entry'
3863 (Enode => N,
3864 Source => Source,
3865 Target => Target));
3866
3867 -- If both sizes are known statically now, then back end annotation
3868 -- is not required to do a proper check but if either size is not
3869 -- known statically, then we need the annotation.
3870
3871 if Known_Static_RM_Size (Source)
3872 and then Known_Static_RM_Size (Target)
3873 then
3874 null;
3875 else
3876 Back_Annotate_Rep_Info := True;
3877 end if;
3878 end if;
3879
3880 -- If unchecked conversion to access type, and access type is
3881 -- declared in the same unit as the unchecked conversion, then
3882 -- set the No_Strict_Aliasing flag (no strict aliasing is
3883 -- implicit in this situation).
3884
3885 if Is_Access_Type (Target) and then
3886 In_Same_Source_Unit (Target, N)
3887 then
3888 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
3889 end if;
3890
3891 -- Generate N_Validate_Unchecked_Conversion node for back end in
3892 -- case the back end needs to perform special validation checks.
3893
3894 -- Shouldn't this be in exp_ch13, since the check only gets done
3895 -- if we have full expansion and the back end is called ???
3896
3897 Vnode :=
3898 Make_Validate_Unchecked_Conversion (Sloc (N));
3899 Set_Source_Type (Vnode, Source);
3900 Set_Target_Type (Vnode, Target);
3901
3902 -- If the unchecked conversion node is in a list, just insert before
3903 -- it. If not we have some strange case, not worth bothering about.
3904
3905 if Is_List_Member (N) then
3906 Insert_After (N, Vnode);
3907 end if;
3908 end Validate_Unchecked_Conversion;
3909
3910 ------------------------------------
3911 -- Validate_Unchecked_Conversions --
3912 ------------------------------------
3913
3914 procedure Validate_Unchecked_Conversions is
3915 begin
3916 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
3917 declare
3918 T : UC_Entry renames Unchecked_Conversions.Table (N);
3919
3920 Enode : constant Node_Id := T.Enode;
3921 Source : constant Entity_Id := T.Source;
3922 Target : constant Entity_Id := T.Target;
3923
3924 Source_Siz : Uint;
3925 Target_Siz : Uint;
3926
3927 begin
3928 -- This validation check, which warns if we have unequal sizes
3929 -- for unchecked conversion, and thus potentially implementation
3930 -- dependent semantics, is one of the few occasions on which we
3931 -- use the official RM size instead of Esize. See description
3932 -- in Einfo "Handling of Type'Size Values" for details.
3933
3934 if Serious_Errors_Detected = 0
3935 and then Known_Static_RM_Size (Source)
3936 and then Known_Static_RM_Size (Target)
3937 then
3938 Source_Siz := RM_Size (Source);
3939 Target_Siz := RM_Size (Target);
3940
3941 if Source_Siz /= Target_Siz then
3942 Error_Msg_N
3943 ("types for unchecked conversion have different sizes?",
3944 Enode);
3945
3946 if All_Errors_Mode then
3947 Error_Msg_Name_1 := Chars (Source);
3948 Error_Msg_Uint_1 := Source_Siz;
3949 Error_Msg_Name_2 := Chars (Target);
3950 Error_Msg_Uint_2 := Target_Siz;
3951 Error_Msg_N
3952 ("\size of % is ^, size of % is ^?", Enode);
3953
3954 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
3955
3956 if Is_Discrete_Type (Source)
3957 and then Is_Discrete_Type (Target)
3958 then
3959 if Source_Siz > Target_Siz then
3960 Error_Msg_N
3961 ("\^ high order bits of source will be ignored?",
3962 Enode);
3963
3964 elsif Is_Unsigned_Type (Source) then
3965 Error_Msg_N
3966 ("\source will be extended with ^ high order " &
3967 "zero bits?", Enode);
3968
3969 else
3970 Error_Msg_N
3971 ("\source will be extended with ^ high order " &
3972 "sign bits?",
3973 Enode);
3974 end if;
3975
3976 elsif Source_Siz < Target_Siz then
3977 if Is_Discrete_Type (Target) then
3978 if Bytes_Big_Endian then
3979 Error_Msg_N
3980 ("\target value will include ^ undefined " &
3981 "low order bits?",
3982 Enode);
3983 else
3984 Error_Msg_N
3985 ("\target value will include ^ undefined " &
3986 "high order bits?",
3987 Enode);
3988 end if;
3989
3990 else
3991 Error_Msg_N
3992 ("\^ trailing bits of target value will be " &
3993 "undefined?", Enode);
3994 end if;
3995
3996 else pragma Assert (Source_Siz > Target_Siz);
3997 Error_Msg_N
3998 ("\^ trailing bits of source will be ignored?",
3999 Enode);
4000 end if;
4001 end if;
4002 end if;
4003 end if;
4004
4005 -- If both types are access types, we need to check the alignment.
4006 -- If the alignment of both is specified, we can do it here.
4007
4008 if Serious_Errors_Detected = 0
4009 and then Ekind (Source) in Access_Kind
4010 and then Ekind (Target) in Access_Kind
4011 and then Target_Strict_Alignment
4012 and then Present (Designated_Type (Source))
4013 and then Present (Designated_Type (Target))
4014 then
4015 declare
4016 D_Source : constant Entity_Id := Designated_Type (Source);
4017 D_Target : constant Entity_Id := Designated_Type (Target);
4018
4019 begin
4020 if Known_Alignment (D_Source)
4021 and then Known_Alignment (D_Target)
4022 then
4023 declare
4024 Source_Align : constant Uint := Alignment (D_Source);
4025 Target_Align : constant Uint := Alignment (D_Target);
4026
4027 begin
4028 if Source_Align < Target_Align
4029 and then not Is_Tagged_Type (D_Source)
4030 then
4031 Error_Msg_Uint_1 := Target_Align;
4032 Error_Msg_Uint_2 := Source_Align;
4033 Error_Msg_Node_2 := D_Source;
4034 Error_Msg_NE
4035 ("alignment of & (^) is stricter than " &
4036 "alignment of & (^)?", Enode, D_Target);
4037
4038 if All_Errors_Mode then
4039 Error_Msg_N
4040 ("\resulting access value may have invalid " &
4041 "alignment?", Enode);
4042 end if;
4043 end if;
4044 end;
4045 end if;
4046 end;
4047 end if;
4048 end;
4049 end loop;
4050 end Validate_Unchecked_Conversions;
4051
4052 end Sem_Ch13;
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