File : exp_strm.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- E X P _ S T R M --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2015, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
26 with Atree; use Atree;
27 with Einfo; use Einfo;
28 with Elists; use Elists;
29 with Exp_Util; use Exp_Util;
30 with Namet; use Namet;
31 with Nlists; use Nlists;
32 with Nmake; use Nmake;
33 with Rtsfind; use Rtsfind;
34 with Sem_Aux; use Sem_Aux;
35 with Sem_Util; use Sem_Util;
36 with Sinfo; use Sinfo;
37 with Snames; use Snames;
38 with Stand; use Stand;
39 with Tbuild; use Tbuild;
40 with Ttypes; use Ttypes;
41 with Uintp; use Uintp;
42
43 package body Exp_Strm is
44
45 -----------------------
46 -- Local Subprograms --
47 -----------------------
48
49 procedure Build_Array_Read_Write_Procedure
50 (Nod : Node_Id;
51 Typ : Entity_Id;
52 Decl : out Node_Id;
53 Pnam : Entity_Id;
54 Nam : Name_Id);
55 -- Common routine shared to build either an array Read procedure or an
56 -- array Write procedure, Nam is Name_Read or Name_Write to select which.
57 -- Pnam is the defining identifier for the constructed procedure. The
58 -- other parameters are as for Build_Array_Read_Procedure except that
59 -- the first parameter Nod supplies the Sloc to be used to generate code.
60
61 procedure Build_Record_Read_Write_Procedure
62 (Loc : Source_Ptr;
63 Typ : Entity_Id;
64 Decl : out Node_Id;
65 Pnam : Entity_Id;
66 Nam : Name_Id);
67 -- Common routine shared to build a record Read Write procedure, Nam
68 -- is Name_Read or Name_Write to select which. Pnam is the defining
69 -- identifier for the constructed procedure. The other parameters are
70 -- as for Build_Record_Read_Procedure.
71
72 procedure Build_Stream_Function
73 (Loc : Source_Ptr;
74 Typ : Entity_Id;
75 Decl : out Node_Id;
76 Fnam : Entity_Id;
77 Decls : List_Id;
78 Stms : List_Id);
79 -- Called to build an array or record stream function. The first three
80 -- arguments are the same as Build_Record_Or_Elementary_Input_Function.
81 -- Decls and Stms are the declarations and statements for the body and
82 -- The parameter Fnam is the name of the constructed function.
83
84 function Has_Stream_Standard_Rep (U_Type : Entity_Id) return Boolean;
85 -- This function is used to test the type U_Type, to determine if it has
86 -- a standard representation from a streaming point of view. Standard means
87 -- that it has a standard representation (e.g. no enumeration rep clause),
88 -- and the size of the root type is the same as the streaming size (which
89 -- is defined as value specified by a Stream_Size clause if present, or
90 -- the Esize of U_Type if not).
91
92 function Make_Stream_Subprogram_Name
93 (Loc : Source_Ptr;
94 Typ : Entity_Id;
95 Nam : TSS_Name_Type) return Entity_Id;
96 -- Return the entity that identifies the stream subprogram for type Typ
97 -- that is identified by the given Nam. This procedure deals with the
98 -- difference between tagged types (where a single subprogram associated
99 -- with the type is generated) and all other cases (where a subprogram
100 -- is generated at the point of the stream attribute reference). The
101 -- Loc parameter is used as the Sloc of the created entity.
102
103 function Stream_Base_Type (E : Entity_Id) return Entity_Id;
104 -- Stream attributes work on the basis of the base type except for the
105 -- array case. For the array case, we do not go to the base type, but
106 -- to the first subtype if it is constrained. This avoids problems with
107 -- incorrect conversions in the packed array case. Stream_Base_Type is
108 -- exactly this function (returns the base type, unless we have an array
109 -- type whose first subtype is constrained, in which case it returns the
110 -- first subtype).
111
112 --------------------------------
113 -- Build_Array_Input_Function --
114 --------------------------------
115
116 -- The function we build looks like
117
118 -- function typSI[_nnn] (S : access RST) return Typ is
119 -- L1 : constant Index_Type_1 := Index_Type_1'Input (S);
120 -- H1 : constant Index_Type_1 := Index_Type_1'Input (S);
121 -- L2 : constant Index_Type_2 := Index_Type_2'Input (S);
122 -- H2 : constant Index_Type_2 := Index_Type_2'Input (S);
123 -- ..
124 -- Ln : constant Index_Type_n := Index_Type_n'Input (S);
125 -- Hn : constant Index_Type_n := Index_Type_n'Input (S);
126 --
127 -- V : Typ'Base (L1 .. H1, L2 .. H2, ... Ln .. Hn)
128
129 -- begin
130 -- Typ'Read (S, V);
131 -- return V;
132 -- end typSI[_nnn]
133
134 -- Note: the suffix [_nnn] is present for untagged types, where we generate
135 -- a local subprogram at the point of the occurrence of the attribute
136 -- reference, so the name must be unique.
137
138 procedure Build_Array_Input_Function
139 (Loc : Source_Ptr;
140 Typ : Entity_Id;
141 Decl : out Node_Id;
142 Fnam : out Entity_Id)
143 is
144 Dim : constant Pos := Number_Dimensions (Typ);
145 Lnam : Name_Id;
146 Hnam : Name_Id;
147 Decls : List_Id;
148 Ranges : List_Id;
149 Stms : List_Id;
150 Rstmt : Node_Id;
151 Indx : Node_Id;
152 Odecl : Node_Id;
153
154 begin
155 Decls := New_List;
156 Ranges := New_List;
157 Indx := First_Index (Typ);
158 for J in 1 .. Dim loop
159 Lnam := New_External_Name ('L', J);
160 Hnam := New_External_Name ('H', J);
161
162 Append_To (Decls,
163 Make_Object_Declaration (Loc,
164 Defining_Identifier => Make_Defining_Identifier (Loc, Lnam),
165 Constant_Present => True,
166 Object_Definition => New_Occurrence_Of (Etype (Indx), Loc),
167 Expression =>
168 Make_Attribute_Reference (Loc,
169 Prefix =>
170 New_Occurrence_Of (Stream_Base_Type (Etype (Indx)), Loc),
171 Attribute_Name => Name_Input,
172 Expressions => New_List (Make_Identifier (Loc, Name_S)))));
173
174 Append_To (Decls,
175 Make_Object_Declaration (Loc,
176 Defining_Identifier => Make_Defining_Identifier (Loc, Hnam),
177 Constant_Present => True,
178 Object_Definition =>
179 New_Occurrence_Of (Stream_Base_Type (Etype (Indx)), Loc),
180 Expression =>
181 Make_Attribute_Reference (Loc,
182 Prefix =>
183 New_Occurrence_Of (Stream_Base_Type (Etype (Indx)), Loc),
184 Attribute_Name => Name_Input,
185 Expressions => New_List (Make_Identifier (Loc, Name_S)))));
186
187 Append_To (Ranges,
188 Make_Range (Loc,
189 Low_Bound => Make_Identifier (Loc, Lnam),
190 High_Bound => Make_Identifier (Loc, Hnam)));
191
192 Next_Index (Indx);
193 end loop;
194
195 -- If the type is constrained, use it directly. Otherwise build a
196 -- subtype indication with the proper bounds.
197
198 if Is_Constrained (Typ) then
199 Odecl :=
200 Make_Object_Declaration (Loc,
201 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
202 Object_Definition => New_Occurrence_Of (Typ, Loc));
203
204 else
205 Odecl :=
206 Make_Object_Declaration (Loc,
207 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
208 Object_Definition =>
209 Make_Subtype_Indication (Loc,
210 Subtype_Mark =>
211 New_Occurrence_Of (Stream_Base_Type (Typ), Loc),
212 Constraint =>
213 Make_Index_Or_Discriminant_Constraint (Loc, Ranges)));
214 end if;
215
216 Rstmt :=
217 Make_Attribute_Reference (Loc,
218 Prefix => New_Occurrence_Of (Typ, Loc),
219 Attribute_Name => Name_Read,
220 Expressions => New_List (
221 Make_Identifier (Loc, Name_S),
222 Make_Identifier (Loc, Name_V)));
223
224 Stms := New_List (
225 Make_Extended_Return_Statement (Loc,
226 Return_Object_Declarations => New_List (Odecl),
227 Handled_Statement_Sequence =>
228 Make_Handled_Sequence_Of_Statements (Loc, New_List (Rstmt))));
229
230 Fnam :=
231 Make_Defining_Identifier (Loc,
232 Chars => Make_TSS_Name_Local (Typ, TSS_Stream_Input));
233
234 Build_Stream_Function (Loc, Typ, Decl, Fnam, Decls, Stms);
235 end Build_Array_Input_Function;
236
237 ----------------------------------
238 -- Build_Array_Output_Procedure --
239 ----------------------------------
240
241 procedure Build_Array_Output_Procedure
242 (Loc : Source_Ptr;
243 Typ : Entity_Id;
244 Decl : out Node_Id;
245 Pnam : out Entity_Id)
246 is
247 Stms : List_Id;
248 Indx : Node_Id;
249
250 begin
251 -- Build series of statements to output bounds
252
253 Indx := First_Index (Typ);
254 Stms := New_List;
255
256 for J in 1 .. Number_Dimensions (Typ) loop
257 Append_To (Stms,
258 Make_Attribute_Reference (Loc,
259 Prefix =>
260 New_Occurrence_Of (Stream_Base_Type (Etype (Indx)), Loc),
261 Attribute_Name => Name_Write,
262 Expressions => New_List (
263 Make_Identifier (Loc, Name_S),
264 Make_Attribute_Reference (Loc,
265 Prefix => Make_Identifier (Loc, Name_V),
266 Attribute_Name => Name_First,
267 Expressions => New_List (
268 Make_Integer_Literal (Loc, J))))));
269
270 Append_To (Stms,
271 Make_Attribute_Reference (Loc,
272 Prefix =>
273 New_Occurrence_Of (Stream_Base_Type (Etype (Indx)), Loc),
274 Attribute_Name => Name_Write,
275 Expressions => New_List (
276 Make_Identifier (Loc, Name_S),
277 Make_Attribute_Reference (Loc,
278 Prefix => Make_Identifier (Loc, Name_V),
279 Attribute_Name => Name_Last,
280 Expressions => New_List (
281 Make_Integer_Literal (Loc, J))))));
282
283 Next_Index (Indx);
284 end loop;
285
286 -- Append Write attribute to write array elements
287
288 Append_To (Stms,
289 Make_Attribute_Reference (Loc,
290 Prefix => New_Occurrence_Of (Typ, Loc),
291 Attribute_Name => Name_Write,
292 Expressions => New_List (
293 Make_Identifier (Loc, Name_S),
294 Make_Identifier (Loc, Name_V))));
295
296 Pnam :=
297 Make_Defining_Identifier (Loc,
298 Chars => Make_TSS_Name_Local (Typ, TSS_Stream_Output));
299
300 Build_Stream_Procedure (Loc, Typ, Decl, Pnam, Stms, False);
301 end Build_Array_Output_Procedure;
302
303 --------------------------------
304 -- Build_Array_Read_Procedure --
305 --------------------------------
306
307 procedure Build_Array_Read_Procedure
308 (Nod : Node_Id;
309 Typ : Entity_Id;
310 Decl : out Node_Id;
311 Pnam : out Entity_Id)
312 is
313 Loc : constant Source_Ptr := Sloc (Nod);
314
315 begin
316 Pnam :=
317 Make_Defining_Identifier (Loc,
318 Chars => Make_TSS_Name_Local (Typ, TSS_Stream_Read));
319 Build_Array_Read_Write_Procedure (Nod, Typ, Decl, Pnam, Name_Read);
320 end Build_Array_Read_Procedure;
321
322 --------------------------------------
323 -- Build_Array_Read_Write_Procedure --
324 --------------------------------------
325
326 -- The form of the array read/write procedure is as follows:
327
328 -- procedure pnam (S : access RST, V : [out] Typ) is
329 -- begin
330 -- for L1 in V'Range (1) loop
331 -- for L2 in V'Range (2) loop
332 -- ...
333 -- for Ln in V'Range (n) loop
334 -- Component_Type'Read/Write (S, V (L1, L2, .. Ln));
335 -- end loop;
336 -- ..
337 -- end loop;
338 -- end loop
339 -- end pnam;
340
341 -- The out keyword for V is supplied in the Read case
342
343 procedure Build_Array_Read_Write_Procedure
344 (Nod : Node_Id;
345 Typ : Entity_Id;
346 Decl : out Node_Id;
347 Pnam : Entity_Id;
348 Nam : Name_Id)
349 is
350 Loc : constant Source_Ptr := Sloc (Nod);
351 Ndim : constant Pos := Number_Dimensions (Typ);
352 Ctyp : constant Entity_Id := Component_Type (Typ);
353
354 Stm : Node_Id;
355 Exl : List_Id;
356 RW : Entity_Id;
357
358 begin
359 -- First build the inner attribute call
360
361 Exl := New_List;
362
363 for J in 1 .. Ndim loop
364 Append_To (Exl, Make_Identifier (Loc, New_External_Name ('L', J)));
365 end loop;
366
367 Stm :=
368 Make_Attribute_Reference (Loc,
369 Prefix => New_Occurrence_Of (Stream_Base_Type (Ctyp), Loc),
370 Attribute_Name => Nam,
371 Expressions => New_List (
372 Make_Identifier (Loc, Name_S),
373 Make_Indexed_Component (Loc,
374 Prefix => Make_Identifier (Loc, Name_V),
375 Expressions => Exl)));
376
377 -- The corresponding stream attribute for the component type of the
378 -- array may be user-defined, and be frozen after the type for which
379 -- we are generating the stream subprogram. In that case, freeze the
380 -- stream attribute of the component type, whose declaration could not
381 -- generate any additional freezing actions in any case.
382
383 if Nam = Name_Read then
384 RW := TSS (Base_Type (Ctyp), TSS_Stream_Read);
385 else
386 RW := TSS (Base_Type (Ctyp), TSS_Stream_Write);
387 end if;
388
389 if Present (RW)
390 and then not Is_Frozen (RW)
391 then
392 Set_Is_Frozen (RW);
393 end if;
394
395 -- Now this is the big loop to wrap that statement up in a sequence
396 -- of loops. The first time around, Stm is the attribute call. The
397 -- second and subsequent times, Stm is an inner loop.
398
399 for J in 1 .. Ndim loop
400 Stm :=
401 Make_Implicit_Loop_Statement (Nod,
402 Iteration_Scheme =>
403 Make_Iteration_Scheme (Loc,
404 Loop_Parameter_Specification =>
405 Make_Loop_Parameter_Specification (Loc,
406 Defining_Identifier =>
407 Make_Defining_Identifier (Loc,
408 Chars => New_External_Name ('L', Ndim - J + 1)),
409
410 Discrete_Subtype_Definition =>
411 Make_Attribute_Reference (Loc,
412 Prefix => Make_Identifier (Loc, Name_V),
413 Attribute_Name => Name_Range,
414
415 Expressions => New_List (
416 Make_Integer_Literal (Loc, Ndim - J + 1))))),
417
418 Statements => New_List (Stm));
419
420 end loop;
421
422 Build_Stream_Procedure
423 (Loc, Typ, Decl, Pnam, New_List (Stm), Nam = Name_Read);
424 end Build_Array_Read_Write_Procedure;
425
426 ---------------------------------
427 -- Build_Array_Write_Procedure --
428 ---------------------------------
429
430 procedure Build_Array_Write_Procedure
431 (Nod : Node_Id;
432 Typ : Entity_Id;
433 Decl : out Node_Id;
434 Pnam : out Entity_Id)
435 is
436 Loc : constant Source_Ptr := Sloc (Nod);
437 begin
438 Pnam :=
439 Make_Defining_Identifier (Loc,
440 Chars => Make_TSS_Name_Local (Typ, TSS_Stream_Write));
441 Build_Array_Read_Write_Procedure (Nod, Typ, Decl, Pnam, Name_Write);
442 end Build_Array_Write_Procedure;
443
444 ---------------------------------
445 -- Build_Elementary_Input_Call --
446 ---------------------------------
447
448 function Build_Elementary_Input_Call (N : Node_Id) return Node_Id is
449 Loc : constant Source_Ptr := Sloc (N);
450 P_Type : constant Entity_Id := Entity (Prefix (N));
451 U_Type : constant Entity_Id := Underlying_Type (P_Type);
452 Rt_Type : constant Entity_Id := Root_Type (U_Type);
453 FST : constant Entity_Id := First_Subtype (U_Type);
454 Strm : constant Node_Id := First (Expressions (N));
455 Targ : constant Node_Id := Next (Strm);
456 P_Size : constant Uint := Get_Stream_Size (FST);
457 Res : Node_Id;
458 Lib_RE : RE_Id;
459
460 begin
461
462 -- Check first for Boolean and Character. These are enumeration types,
463 -- but we treat them specially, since they may require special handling
464 -- in the transfer protocol. However, this special handling only applies
465 -- if they have standard representation, otherwise they are treated like
466 -- any other enumeration type.
467
468 if Rt_Type = Standard_Boolean
469 and then Has_Stream_Standard_Rep (U_Type)
470 then
471 Lib_RE := RE_I_B;
472
473 elsif Rt_Type = Standard_Character
474 and then Has_Stream_Standard_Rep (U_Type)
475 then
476 Lib_RE := RE_I_C;
477
478 elsif Rt_Type = Standard_Wide_Character
479 and then Has_Stream_Standard_Rep (U_Type)
480 then
481 Lib_RE := RE_I_WC;
482
483 elsif Rt_Type = Standard_Wide_Wide_Character
484 and then Has_Stream_Standard_Rep (U_Type)
485 then
486 Lib_RE := RE_I_WWC;
487
488 -- Floating point types
489
490 elsif Is_Floating_Point_Type (U_Type) then
491
492 -- Question: should we use P_Size or Rt_Type to distinguish between
493 -- possible floating point types? If a non-standard size or a stream
494 -- size is specified, then we should certainly use the size. But if
495 -- we have two types the same (notably Short_Float_Size = Float_Size
496 -- which is close to universally true, and Long_Long_Float_Size =
497 -- Long_Float_Size, true on most targets except the x86), then we
498 -- would really rather use the root type, so that if people want to
499 -- fiddle with System.Stream_Attributes to get inter-target portable
500 -- streams, they get the size they expect. Consider in particular the
501 -- case of a stream written on an x86, with 96-bit Long_Long_Float
502 -- being read into a non-x86 target with 64 bit Long_Long_Float. A
503 -- special version of System.Stream_Attributes can deal with this
504 -- provided the proper type is always used.
505
506 -- To deal with these two requirements we add the special checks
507 -- on equal sizes and use the root type to distinguish.
508
509 if P_Size <= Standard_Short_Float_Size
510 and then (Standard_Short_Float_Size /= Standard_Float_Size
511 or else Rt_Type = Standard_Short_Float)
512 then
513 Lib_RE := RE_I_SF;
514
515 elsif P_Size <= Standard_Float_Size then
516 Lib_RE := RE_I_F;
517
518 elsif P_Size <= Standard_Long_Float_Size
519 and then (Standard_Long_Float_Size /= Standard_Long_Long_Float_Size
520 or else Rt_Type = Standard_Long_Float)
521 then
522 Lib_RE := RE_I_LF;
523
524 else
525 Lib_RE := RE_I_LLF;
526 end if;
527
528 -- Signed integer types. Also includes signed fixed-point types and
529 -- enumeration types with a signed representation.
530
531 -- Note on signed integer types. We do not consider types as signed for
532 -- this purpose if they have no negative numbers, or if they have biased
533 -- representation. The reason is that the value in either case basically
534 -- represents an unsigned value.
535
536 -- For example, consider:
537
538 -- type W is range 0 .. 2**32 - 1;
539 -- for W'Size use 32;
540
541 -- This is a signed type, but the representation is unsigned, and may
542 -- be outside the range of a 32-bit signed integer, so this must be
543 -- treated as 32-bit unsigned.
544
545 -- Similarly, if we have
546
547 -- type W is range -1 .. +254;
548 -- for W'Size use 8;
549
550 -- then the representation is unsigned
551
552 elsif not Is_Unsigned_Type (FST)
553
554 -- The following set of tests gets repeated many times, we should
555 -- have an abstraction defined ???
556
557 and then
558 (Is_Fixed_Point_Type (U_Type)
559 or else
560 Is_Enumeration_Type (U_Type)
561 or else
562 (Is_Signed_Integer_Type (U_Type)
563 and then not Has_Biased_Representation (FST)))
564
565 then
566 if P_Size <= Standard_Short_Short_Integer_Size then
567 Lib_RE := RE_I_SSI;
568
569 elsif P_Size <= Standard_Short_Integer_Size then
570 Lib_RE := RE_I_SI;
571
572 elsif P_Size <= Standard_Integer_Size then
573 Lib_RE := RE_I_I;
574
575 elsif P_Size <= Standard_Long_Integer_Size then
576 Lib_RE := RE_I_LI;
577
578 else
579 Lib_RE := RE_I_LLI;
580 end if;
581
582 -- Unsigned integer types, also includes unsigned fixed-point types
583 -- and enumeration types with an unsigned representation (note that
584 -- we know they are unsigned because we already tested for signed).
585
586 -- Also includes signed integer types that are unsigned in the sense
587 -- that they do not include negative numbers. See above for details.
588
589 elsif Is_Modular_Integer_Type (U_Type)
590 or else Is_Fixed_Point_Type (U_Type)
591 or else Is_Enumeration_Type (U_Type)
592 or else Is_Signed_Integer_Type (U_Type)
593 then
594 if P_Size <= Standard_Short_Short_Integer_Size then
595 Lib_RE := RE_I_SSU;
596
597 elsif P_Size <= Standard_Short_Integer_Size then
598 Lib_RE := RE_I_SU;
599
600 elsif P_Size <= Standard_Integer_Size then
601 Lib_RE := RE_I_U;
602
603 elsif P_Size <= Standard_Long_Integer_Size then
604 Lib_RE := RE_I_LU;
605
606 else
607 Lib_RE := RE_I_LLU;
608 end if;
609
610 else pragma Assert (Is_Access_Type (U_Type));
611 if P_Size > System_Address_Size then
612 Lib_RE := RE_I_AD;
613 else
614 Lib_RE := RE_I_AS;
615 end if;
616 end if;
617
618 -- Call the function, and do an unchecked conversion of the result
619 -- to the actual type of the prefix. If the target is a discriminant,
620 -- and we are in the body of the default implementation of a 'Read
621 -- attribute, set target type to force a constraint check (13.13.2(35)).
622 -- If the type of the discriminant is currently private, add another
623 -- unchecked conversion from the full view.
624
625 if Nkind (Targ) = N_Identifier
626 and then Is_Internal_Name (Chars (Targ))
627 and then Is_TSS (Scope (Entity (Targ)), TSS_Stream_Read)
628 then
629 Res :=
630 Unchecked_Convert_To (Base_Type (U_Type),
631 Make_Function_Call (Loc,
632 Name => New_Occurrence_Of (RTE (Lib_RE), Loc),
633 Parameter_Associations => New_List (
634 Relocate_Node (Strm))));
635
636 Set_Do_Range_Check (Res);
637
638 if Base_Type (P_Type) /= Base_Type (U_Type) then
639 Res := Unchecked_Convert_To (Base_Type (P_Type), Res);
640 end if;
641
642 return Res;
643
644 else
645 Res :=
646 Make_Function_Call (Loc,
647 Name => New_Occurrence_Of (RTE (Lib_RE), Loc),
648 Parameter_Associations => New_List (
649 Relocate_Node (Strm)));
650
651 -- Now convert to the base type if we do not have a biased type. Note
652 -- that we did not do this in some older versions, and the result was
653 -- losing a required range check in the case where 'Input is being
654 -- called from 'Read.
655
656 if not Has_Biased_Representation (P_Type) then
657 return Unchecked_Convert_To (Base_Type (P_Type), Res);
658
659 -- For the biased case, the conversion to the base type loses the
660 -- biasing, so just convert to Ptype. This is not quite right, and
661 -- for example may lose a corner case CE test, but it is such a
662 -- rare case that for now we ignore it ???
663
664 else
665 return Unchecked_Convert_To (P_Type, Res);
666 end if;
667 end if;
668 end Build_Elementary_Input_Call;
669
670 ---------------------------------
671 -- Build_Elementary_Write_Call --
672 ---------------------------------
673
674 function Build_Elementary_Write_Call (N : Node_Id) return Node_Id is
675 Loc : constant Source_Ptr := Sloc (N);
676 P_Type : constant Entity_Id := Entity (Prefix (N));
677 U_Type : constant Entity_Id := Underlying_Type (P_Type);
678 Rt_Type : constant Entity_Id := Root_Type (U_Type);
679 FST : constant Entity_Id := First_Subtype (U_Type);
680 Strm : constant Node_Id := First (Expressions (N));
681 Item : constant Node_Id := Next (Strm);
682 P_Size : Uint;
683 Lib_RE : RE_Id;
684 Libent : Entity_Id;
685
686 begin
687 -- Compute the size of the stream element. This is either the size of
688 -- the first subtype or if given the size of the Stream_Size attribute.
689
690 if Has_Stream_Size_Clause (FST) then
691 P_Size := Static_Integer (Expression (Stream_Size_Clause (FST)));
692 else
693 P_Size := Esize (FST);
694 end if;
695
696 -- Find the routine to be called
697
698 -- Check for First Boolean and Character. These are enumeration types,
699 -- but we treat them specially, since they may require special handling
700 -- in the transfer protocol. However, this special handling only applies
701 -- if they have standard representation, otherwise they are treated like
702 -- any other enumeration type.
703
704 if Rt_Type = Standard_Boolean
705 and then Has_Stream_Standard_Rep (U_Type)
706 then
707 Lib_RE := RE_W_B;
708
709 elsif Rt_Type = Standard_Character
710 and then Has_Stream_Standard_Rep (U_Type)
711 then
712 Lib_RE := RE_W_C;
713
714 elsif Rt_Type = Standard_Wide_Character
715 and then Has_Stream_Standard_Rep (U_Type)
716 then
717 Lib_RE := RE_W_WC;
718
719 elsif Rt_Type = Standard_Wide_Wide_Character
720 and then Has_Stream_Standard_Rep (U_Type)
721 then
722 Lib_RE := RE_W_WWC;
723
724 -- Floating point types
725
726 elsif Is_Floating_Point_Type (U_Type) then
727
728 -- Question: should we use P_Size or Rt_Type to distinguish between
729 -- possible floating point types? If a non-standard size or a stream
730 -- size is specified, then we should certainly use the size. But if
731 -- we have two types the same (notably Short_Float_Size = Float_Size
732 -- which is close to universally true, and Long_Long_Float_Size =
733 -- Long_Float_Size, true on most targets except the x86), then we
734 -- would really rather use the root type, so that if people want to
735 -- fiddle with System.Stream_Attributes to get inter-target portable
736 -- streams, they get the size they expect. Consider in particular the
737 -- case of a stream written on an x86, with 96-bit Long_Long_Float
738 -- being read into a non-x86 target with 64 bit Long_Long_Float. A
739 -- special version of System.Stream_Attributes can deal with this
740 -- provided the proper type is always used.
741
742 -- To deal with these two requirements we add the special checks
743 -- on equal sizes and use the root type to distinguish.
744
745 if P_Size <= Standard_Short_Float_Size
746 and then (Standard_Short_Float_Size /= Standard_Float_Size
747 or else Rt_Type = Standard_Short_Float)
748 then
749 Lib_RE := RE_W_SF;
750
751 elsif P_Size <= Standard_Float_Size then
752 Lib_RE := RE_W_F;
753
754 elsif P_Size <= Standard_Long_Float_Size
755 and then (Standard_Long_Float_Size /= Standard_Long_Long_Float_Size
756 or else Rt_Type = Standard_Long_Float)
757 then
758 Lib_RE := RE_W_LF;
759
760 else
761 Lib_RE := RE_W_LLF;
762 end if;
763
764 -- Signed integer types. Also includes signed fixed-point types and
765 -- signed enumeration types share this circuitry.
766
767 -- Note on signed integer types. We do not consider types as signed for
768 -- this purpose if they have no negative numbers, or if they have biased
769 -- representation. The reason is that the value in either case basically
770 -- represents an unsigned value.
771
772 -- For example, consider:
773
774 -- type W is range 0 .. 2**32 - 1;
775 -- for W'Size use 32;
776
777 -- This is a signed type, but the representation is unsigned, and may
778 -- be outside the range of a 32-bit signed integer, so this must be
779 -- treated as 32-bit unsigned.
780
781 -- Similarly, the representation is also unsigned if we have:
782
783 -- type W is range -1 .. +254;
784 -- for W'Size use 8;
785
786 -- forcing a biased and unsigned representation
787
788 elsif not Is_Unsigned_Type (FST)
789 and then
790 (Is_Fixed_Point_Type (U_Type)
791 or else
792 Is_Enumeration_Type (U_Type)
793 or else
794 (Is_Signed_Integer_Type (U_Type)
795 and then not Has_Biased_Representation (FST)))
796 then
797 if P_Size <= Standard_Short_Short_Integer_Size then
798 Lib_RE := RE_W_SSI;
799 elsif P_Size <= Standard_Short_Integer_Size then
800 Lib_RE := RE_W_SI;
801 elsif P_Size <= Standard_Integer_Size then
802 Lib_RE := RE_W_I;
803 elsif P_Size <= Standard_Long_Integer_Size then
804 Lib_RE := RE_W_LI;
805 else
806 Lib_RE := RE_W_LLI;
807 end if;
808
809 -- Unsigned integer types, also includes unsigned fixed-point types
810 -- and unsigned enumeration types (note we know they are unsigned
811 -- because we already tested for signed above).
812
813 -- Also includes signed integer types that are unsigned in the sense
814 -- that they do not include negative numbers. See above for details.
815
816 elsif Is_Modular_Integer_Type (U_Type)
817 or else Is_Fixed_Point_Type (U_Type)
818 or else Is_Enumeration_Type (U_Type)
819 or else Is_Signed_Integer_Type (U_Type)
820 then
821 if P_Size <= Standard_Short_Short_Integer_Size then
822 Lib_RE := RE_W_SSU;
823 elsif P_Size <= Standard_Short_Integer_Size then
824 Lib_RE := RE_W_SU;
825 elsif P_Size <= Standard_Integer_Size then
826 Lib_RE := RE_W_U;
827 elsif P_Size <= Standard_Long_Integer_Size then
828 Lib_RE := RE_W_LU;
829 else
830 Lib_RE := RE_W_LLU;
831 end if;
832
833 else pragma Assert (Is_Access_Type (U_Type));
834
835 if P_Size > System_Address_Size then
836 Lib_RE := RE_W_AD;
837 else
838 Lib_RE := RE_W_AS;
839 end if;
840 end if;
841
842 -- Unchecked-convert parameter to the required type (i.e. the type of
843 -- the corresponding parameter, and call the appropriate routine.
844
845 Libent := RTE (Lib_RE);
846
847 return
848 Make_Procedure_Call_Statement (Loc,
849 Name => New_Occurrence_Of (Libent, Loc),
850 Parameter_Associations => New_List (
851 Relocate_Node (Strm),
852 Unchecked_Convert_To (Etype (Next_Formal (First_Formal (Libent))),
853 Relocate_Node (Item))));
854 end Build_Elementary_Write_Call;
855
856 -----------------------------------------
857 -- Build_Mutable_Record_Read_Procedure --
858 -----------------------------------------
859
860 procedure Build_Mutable_Record_Read_Procedure
861 (Loc : Source_Ptr;
862 Typ : Entity_Id;
863 Decl : out Node_Id;
864 Pnam : out Entity_Id)
865 is
866 Out_Formal : Node_Id;
867 -- Expression denoting the out formal parameter
868
869 Dcls : constant List_Id := New_List;
870 -- Declarations for the 'Read body
871
872 Stms : constant List_Id := New_List;
873 -- Statements for the 'Read body
874
875 Disc : Entity_Id;
876 -- Entity of the discriminant being processed
877
878 Tmp_For_Disc : Entity_Id;
879 -- Temporary object used to read the value of Disc
880
881 Tmps_For_Discs : constant List_Id := New_List;
882 -- List of object declarations for temporaries holding the read values
883 -- for the discriminants.
884
885 Cstr : constant List_Id := New_List;
886 -- List of constraints to be applied on temporary record
887
888 Discriminant_Checks : constant List_Id := New_List;
889 -- List of discriminant checks to be performed if the actual object
890 -- is constrained.
891
892 Tmp : constant Entity_Id := Make_Defining_Identifier (Loc, Name_V);
893 -- Temporary record must hide formal (assignments to components of the
894 -- record are always generated with V as the identifier for the record).
895
896 Constrained_Stms : List_Id := New_List;
897 -- Statements within the block where we have the constrained temporary
898
899 begin
900 -- A mutable type cannot be a tagged type, so we generate a new name
901 -- for the stream procedure.
902
903 Pnam :=
904 Make_Defining_Identifier (Loc,
905 Chars => Make_TSS_Name_Local (Typ, TSS_Stream_Read));
906
907 if Is_Unchecked_Union (Typ) then
908
909 -- If this is an unchecked union, the stream procedure is erroneous,
910 -- because there are no discriminants to read.
911
912 -- This should generate a warning ???
913
914 Append_To (Stms,
915 Make_Raise_Program_Error (Loc,
916 Reason => PE_Unchecked_Union_Restriction));
917
918 Build_Stream_Procedure (Loc, Typ, Decl, Pnam, Stms, Outp => True);
919 return;
920 end if;
921
922 Disc := First_Discriminant (Typ);
923
924 Out_Formal :=
925 Make_Selected_Component (Loc,
926 Prefix => New_Occurrence_Of (Pnam, Loc),
927 Selector_Name => Make_Identifier (Loc, Name_V));
928
929 -- Generate Reads for the discriminants of the type. The discriminants
930 -- need to be read before the rest of the components, so that variants
931 -- are initialized correctly. The discriminants must be read into temp
932 -- variables so an incomplete Read (interrupted by an exception, for
933 -- example) does not alter the passed object.
934
935 while Present (Disc) loop
936 Tmp_For_Disc := Make_Defining_Identifier (Loc,
937 New_External_Name (Chars (Disc), "D"));
938
939 Append_To (Tmps_For_Discs,
940 Make_Object_Declaration (Loc,
941 Defining_Identifier => Tmp_For_Disc,
942 Object_Definition => New_Occurrence_Of (Etype (Disc), Loc)));
943 Set_No_Initialization (Last (Tmps_For_Discs));
944
945 Append_To (Stms,
946 Make_Attribute_Reference (Loc,
947 Prefix => New_Occurrence_Of (Etype (Disc), Loc),
948 Attribute_Name => Name_Read,
949 Expressions => New_List (
950 Make_Identifier (Loc, Name_S),
951 New_Occurrence_Of (Tmp_For_Disc, Loc))));
952
953 Append_To (Cstr,
954 Make_Discriminant_Association (Loc,
955 Selector_Names => New_List (New_Occurrence_Of (Disc, Loc)),
956 Expression => New_Occurrence_Of (Tmp_For_Disc, Loc)));
957
958 Append_To (Discriminant_Checks,
959 Make_Raise_Constraint_Error (Loc,
960 Condition =>
961 Make_Op_Ne (Loc,
962 Left_Opnd => New_Occurrence_Of (Tmp_For_Disc, Loc),
963 Right_Opnd =>
964 Make_Selected_Component (Loc,
965 Prefix => New_Copy_Tree (Out_Formal),
966 Selector_Name => New_Occurrence_Of (Disc, Loc))),
967 Reason => CE_Discriminant_Check_Failed));
968 Next_Discriminant (Disc);
969 end loop;
970
971 -- Generate reads for the components of the record (including those
972 -- that depend on discriminants).
973
974 Build_Record_Read_Write_Procedure (Loc, Typ, Decl, Pnam, Name_Read);
975
976 -- Save original statement sequence for component assignments, and
977 -- replace it with Stms.
978
979 Constrained_Stms := Statements (Handled_Statement_Sequence (Decl));
980 Set_Handled_Statement_Sequence (Decl,
981 Make_Handled_Sequence_Of_Statements (Loc,
982 Statements => Stms));
983
984 -- If Typ has controlled components (i.e. if it is classwide or
985 -- Has_Controlled), or components constrained using the discriminants
986 -- of Typ, then we need to ensure that all component assignments are
987 -- performed on an object that has been appropriately constrained
988 -- prior to being initialized. To this effect, we wrap the component
989 -- assignments in a block where V is a constrained temporary.
990
991 Append_To (Dcls,
992 Make_Object_Declaration (Loc,
993 Defining_Identifier => Tmp,
994 Object_Definition =>
995 Make_Subtype_Indication (Loc,
996 Subtype_Mark => New_Occurrence_Of (Base_Type (Typ), Loc),
997 Constraint =>
998 Make_Index_Or_Discriminant_Constraint (Loc,
999 Constraints => Cstr))));
1000
1001 -- AI05-023-1: Insert discriminant check prior to initialization of the
1002 -- constrained temporary.
1003
1004 Append_To (Stms,
1005 Make_Implicit_If_Statement (Pnam,
1006 Condition =>
1007 Make_Attribute_Reference (Loc,
1008 Prefix => New_Copy_Tree (Out_Formal),
1009 Attribute_Name => Name_Constrained),
1010 Then_Statements => Discriminant_Checks));
1011
1012 -- Now insert back original component assignments, wrapped in a block
1013 -- in which V is the constrained temporary.
1014
1015 Append_To (Stms,
1016 Make_Block_Statement (Loc,
1017 Declarations => Dcls,
1018 Handled_Statement_Sequence => Parent (Constrained_Stms)));
1019
1020 Append_To (Constrained_Stms,
1021 Make_Assignment_Statement (Loc,
1022 Name => Out_Formal,
1023 Expression => Make_Identifier (Loc, Name_V)));
1024
1025 Set_Declarations (Decl, Tmps_For_Discs);
1026 end Build_Mutable_Record_Read_Procedure;
1027
1028 ------------------------------------------
1029 -- Build_Mutable_Record_Write_Procedure --
1030 ------------------------------------------
1031
1032 procedure Build_Mutable_Record_Write_Procedure
1033 (Loc : Source_Ptr;
1034 Typ : Entity_Id;
1035 Decl : out Node_Id;
1036 Pnam : out Entity_Id)
1037 is
1038 Stms : List_Id;
1039 Disc : Entity_Id;
1040 D_Ref : Node_Id;
1041
1042 begin
1043 Stms := New_List;
1044 Disc := First_Discriminant (Typ);
1045
1046 -- Generate Writes for the discriminants of the type
1047 -- If the type is an unchecked union, use the default values of
1048 -- the discriminants, because they are not stored.
1049
1050 while Present (Disc) loop
1051 if Is_Unchecked_Union (Typ) then
1052 D_Ref :=
1053 New_Copy_Tree (Discriminant_Default_Value (Disc));
1054 else
1055 D_Ref :=
1056 Make_Selected_Component (Loc,
1057 Prefix => Make_Identifier (Loc, Name_V),
1058 Selector_Name => New_Occurrence_Of (Disc, Loc));
1059 end if;
1060
1061 Append_To (Stms,
1062 Make_Attribute_Reference (Loc,
1063 Prefix => New_Occurrence_Of (Etype (Disc), Loc),
1064 Attribute_Name => Name_Write,
1065 Expressions => New_List (
1066 Make_Identifier (Loc, Name_S),
1067 D_Ref)));
1068
1069 Next_Discriminant (Disc);
1070 end loop;
1071
1072 -- A mutable type cannot be a tagged type, so we generate a new name
1073 -- for the stream procedure.
1074
1075 Pnam :=
1076 Make_Defining_Identifier (Loc,
1077 Chars => Make_TSS_Name_Local (Typ, TSS_Stream_Write));
1078 Build_Record_Read_Write_Procedure (Loc, Typ, Decl, Pnam, Name_Write);
1079
1080 -- Write the discriminants before the rest of the components, so
1081 -- that discriminant values are properly set of variants, etc.
1082
1083 if Is_Non_Empty_List (
1084 Statements (Handled_Statement_Sequence (Decl)))
1085 then
1086 Insert_List_Before
1087 (First (Statements (Handled_Statement_Sequence (Decl))), Stms);
1088 else
1089 Set_Statements (Handled_Statement_Sequence (Decl), Stms);
1090 end if;
1091 end Build_Mutable_Record_Write_Procedure;
1092
1093 -----------------------------------------------
1094 -- Build_Record_Or_Elementary_Input_Function --
1095 -----------------------------------------------
1096
1097 -- The function we build looks like
1098
1099 -- function InputN (S : access RST) return Typ is
1100 -- C1 : constant Disc_Type_1;
1101 -- Discr_Type_1'Read (S, C1);
1102 -- C2 : constant Disc_Type_2;
1103 -- Discr_Type_2'Read (S, C2);
1104 -- ...
1105 -- Cn : constant Disc_Type_n;
1106 -- Discr_Type_n'Read (S, Cn);
1107 -- V : Typ (C1, C2, .. Cn)
1108
1109 -- begin
1110 -- Typ'Read (S, V);
1111 -- return V;
1112 -- end InputN
1113
1114 -- The discriminants are of course only present in the case of a record
1115 -- with discriminants. In the case of a record with no discriminants, or
1116 -- an elementary type, then no Cn constants are defined.
1117
1118 procedure Build_Record_Or_Elementary_Input_Function
1119 (Loc : Source_Ptr;
1120 Typ : Entity_Id;
1121 Decl : out Node_Id;
1122 Fnam : out Entity_Id)
1123 is
1124 B_Typ : constant Entity_Id := Underlying_Type (Base_Type (Typ));
1125 Cn : Name_Id;
1126 Constr : List_Id;
1127 Decls : List_Id;
1128 Discr : Entity_Id;
1129 Discr_Elmt : Elmt_Id := No_Elmt;
1130 J : Pos;
1131 Obj_Decl : Node_Id;
1132 Odef : Node_Id;
1133 Stms : List_Id;
1134
1135 begin
1136 Decls := New_List;
1137 Constr := New_List;
1138
1139 J := 1;
1140
1141 -- In the presence of multiple instantiations (as in uses of the Booch
1142 -- components) the base type may be private, and the underlying type
1143 -- already constrained, in which case there's no discriminant constraint
1144 -- to construct.
1145
1146 if Has_Discriminants (Typ)
1147 and then No (Discriminant_Default_Value (First_Discriminant (Typ)))
1148 and then not Is_Constrained (Underlying_Type (B_Typ))
1149 then
1150 Discr := First_Discriminant (B_Typ);
1151
1152 -- If the prefix subtype is constrained, then retrieve the first
1153 -- element of its constraint.
1154
1155 if Is_Constrained (Typ) then
1156 Discr_Elmt := First_Elmt (Discriminant_Constraint (Typ));
1157 end if;
1158
1159 while Present (Discr) loop
1160 Cn := New_External_Name ('C', J);
1161
1162 Decl :=
1163 Make_Object_Declaration (Loc,
1164 Defining_Identifier => Make_Defining_Identifier (Loc, Cn),
1165 Object_Definition =>
1166 New_Occurrence_Of (Etype (Discr), Loc));
1167
1168 -- If this is an access discriminant, do not perform default
1169 -- initialization. The discriminant is about to get its value
1170 -- from Read, and if the type is null excluding we do not want
1171 -- spurious warnings on an initial null value.
1172
1173 if Is_Access_Type (Etype (Discr)) then
1174 Set_No_Initialization (Decl);
1175 end if;
1176
1177 Append_To (Decls, Decl);
1178 Append_To (Decls,
1179 Make_Attribute_Reference (Loc,
1180 Prefix => New_Occurrence_Of (Etype (Discr), Loc),
1181 Attribute_Name => Name_Read,
1182 Expressions => New_List (
1183 Make_Identifier (Loc, Name_S),
1184 Make_Identifier (Loc, Cn))));
1185
1186 Append_To (Constr, Make_Identifier (Loc, Cn));
1187
1188 -- If the prefix subtype imposes a discriminant constraint, then
1189 -- check that each discriminant value equals the value read.
1190
1191 if Present (Discr_Elmt) then
1192 Append_To (Decls,
1193 Make_Raise_Constraint_Error (Loc,
1194 Condition => Make_Op_Ne (Loc,
1195 Left_Opnd =>
1196 New_Occurrence_Of
1197 (Defining_Identifier (Decl), Loc),
1198 Right_Opnd =>
1199 New_Copy_Tree (Node (Discr_Elmt))),
1200 Reason => CE_Discriminant_Check_Failed));
1201
1202 Next_Elmt (Discr_Elmt);
1203 end if;
1204
1205 Next_Discriminant (Discr);
1206 J := J + 1;
1207 end loop;
1208
1209 Odef :=
1210 Make_Subtype_Indication (Loc,
1211 Subtype_Mark => New_Occurrence_Of (B_Typ, Loc),
1212 Constraint =>
1213 Make_Index_Or_Discriminant_Constraint (Loc,
1214 Constraints => Constr));
1215
1216 -- If no discriminants, then just use the type with no constraint
1217
1218 else
1219 Odef := New_Occurrence_Of (B_Typ, Loc);
1220 end if;
1221
1222 -- Create an extended return statement encapsulating the result object
1223 -- and 'Read call, which is needed in general for proper handling of
1224 -- build-in-place results (such as when the result type is inherently
1225 -- limited).
1226
1227 Obj_Decl :=
1228 Make_Object_Declaration (Loc,
1229 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
1230 Object_Definition => Odef);
1231
1232 -- If the type is an access type, do not perform default initialization.
1233 -- The object is about to get its value from Read, and if the type is
1234 -- null excluding we do not want spurious warnings on an initial null.
1235
1236 if Is_Access_Type (B_Typ) then
1237 Set_No_Initialization (Obj_Decl);
1238 end if;
1239
1240 Stms := New_List (
1241 Make_Extended_Return_Statement (Loc,
1242 Return_Object_Declarations => New_List (Obj_Decl),
1243 Handled_Statement_Sequence =>
1244 Make_Handled_Sequence_Of_Statements (Loc,
1245 Statements => New_List (
1246 Make_Attribute_Reference (Loc,
1247 Prefix => New_Occurrence_Of (B_Typ, Loc),
1248 Attribute_Name => Name_Read,
1249 Expressions => New_List (
1250 Make_Identifier (Loc, Name_S),
1251 Make_Identifier (Loc, Name_V)))))));
1252
1253 Fnam := Make_Stream_Subprogram_Name (Loc, B_Typ, TSS_Stream_Input);
1254
1255 Build_Stream_Function (Loc, B_Typ, Decl, Fnam, Decls, Stms);
1256 end Build_Record_Or_Elementary_Input_Function;
1257
1258 -------------------------------------------------
1259 -- Build_Record_Or_Elementary_Output_Procedure --
1260 -------------------------------------------------
1261
1262 procedure Build_Record_Or_Elementary_Output_Procedure
1263 (Loc : Source_Ptr;
1264 Typ : Entity_Id;
1265 Decl : out Node_Id;
1266 Pnam : out Entity_Id)
1267 is
1268 Stms : List_Id;
1269 Disc : Entity_Id;
1270 Disc_Ref : Node_Id;
1271
1272 begin
1273 Stms := New_List;
1274
1275 -- Note that of course there will be no discriminants for the elementary
1276 -- type case, so Has_Discriminants will be False. Note that the language
1277 -- rules do not allow writing the discriminants in the defaulted case,
1278 -- because those are written by 'Write.
1279
1280 if Has_Discriminants (Typ)
1281 and then No (Discriminant_Default_Value (First_Discriminant (Typ)))
1282 then
1283 Disc := First_Discriminant (Typ);
1284 while Present (Disc) loop
1285
1286 -- If the type is an unchecked union, it must have default
1287 -- discriminants (this is checked earlier), and those defaults
1288 -- are written out to the stream.
1289
1290 if Is_Unchecked_Union (Typ) then
1291 Disc_Ref := New_Copy_Tree (Discriminant_Default_Value (Disc));
1292
1293 else
1294 Disc_Ref :=
1295 Make_Selected_Component (Loc,
1296 Prefix => Make_Identifier (Loc, Name_V),
1297 Selector_Name => New_Occurrence_Of (Disc, Loc));
1298 end if;
1299
1300 Append_To (Stms,
1301 Make_Attribute_Reference (Loc,
1302 Prefix =>
1303 New_Occurrence_Of (Stream_Base_Type (Etype (Disc)), Loc),
1304 Attribute_Name => Name_Write,
1305 Expressions => New_List (
1306 Make_Identifier (Loc, Name_S),
1307 Disc_Ref)));
1308
1309 Next_Discriminant (Disc);
1310 end loop;
1311 end if;
1312
1313 Append_To (Stms,
1314 Make_Attribute_Reference (Loc,
1315 Prefix => New_Occurrence_Of (Typ, Loc),
1316 Attribute_Name => Name_Write,
1317 Expressions => New_List (
1318 Make_Identifier (Loc, Name_S),
1319 Make_Identifier (Loc, Name_V))));
1320
1321 Pnam := Make_Stream_Subprogram_Name (Loc, Typ, TSS_Stream_Output);
1322
1323 Build_Stream_Procedure (Loc, Typ, Decl, Pnam, Stms, False);
1324 end Build_Record_Or_Elementary_Output_Procedure;
1325
1326 ---------------------------------
1327 -- Build_Record_Read_Procedure --
1328 ---------------------------------
1329
1330 procedure Build_Record_Read_Procedure
1331 (Loc : Source_Ptr;
1332 Typ : Entity_Id;
1333 Decl : out Node_Id;
1334 Pnam : out Entity_Id)
1335 is
1336 begin
1337 Pnam := Make_Stream_Subprogram_Name (Loc, Typ, TSS_Stream_Read);
1338 Build_Record_Read_Write_Procedure (Loc, Typ, Decl, Pnam, Name_Read);
1339 end Build_Record_Read_Procedure;
1340
1341 ---------------------------------------
1342 -- Build_Record_Read_Write_Procedure --
1343 ---------------------------------------
1344
1345 -- The form of the record read/write procedure is as shown by the
1346 -- following example for a case with one discriminant case variant:
1347
1348 -- procedure pnam (S : access RST, V : [out] Typ) is
1349 -- begin
1350 -- Component_Type'Read/Write (S, V.component);
1351 -- Component_Type'Read/Write (S, V.component);
1352 -- ...
1353 -- Component_Type'Read/Write (S, V.component);
1354 --
1355 -- case V.discriminant is
1356 -- when choices =>
1357 -- Component_Type'Read/Write (S, V.component);
1358 -- Component_Type'Read/Write (S, V.component);
1359 -- ...
1360 -- Component_Type'Read/Write (S, V.component);
1361 --
1362 -- when choices =>
1363 -- Component_Type'Read/Write (S, V.component);
1364 -- Component_Type'Read/Write (S, V.component);
1365 -- ...
1366 -- Component_Type'Read/Write (S, V.component);
1367 -- ...
1368 -- end case;
1369 -- end pnam;
1370
1371 -- The out keyword for V is supplied in the Read case
1372
1373 procedure Build_Record_Read_Write_Procedure
1374 (Loc : Source_Ptr;
1375 Typ : Entity_Id;
1376 Decl : out Node_Id;
1377 Pnam : Entity_Id;
1378 Nam : Name_Id)
1379 is
1380 Rdef : Node_Id;
1381 Stms : List_Id;
1382 Typt : Entity_Id;
1383
1384 In_Limited_Extension : Boolean := False;
1385 -- Set to True while processing the record extension definition
1386 -- for an extension of a limited type (for which an ancestor type
1387 -- has an explicit Nam attribute definition).
1388
1389 function Make_Component_List_Attributes (CL : Node_Id) return List_Id;
1390 -- Returns a sequence of attributes to process the components that
1391 -- are referenced in the given component list.
1392
1393 function Make_Field_Attribute (C : Entity_Id) return Node_Id;
1394 -- Given C, the entity for a discriminant or component, build
1395 -- an attribute for the corresponding field values.
1396
1397 function Make_Field_Attributes (Clist : List_Id) return List_Id;
1398 -- Given Clist, a component items list, construct series of attributes
1399 -- for fieldwise processing of the corresponding components.
1400
1401 ------------------------------------
1402 -- Make_Component_List_Attributes --
1403 ------------------------------------
1404
1405 function Make_Component_List_Attributes (CL : Node_Id) return List_Id is
1406 CI : constant List_Id := Component_Items (CL);
1407 VP : constant Node_Id := Variant_Part (CL);
1408
1409 Result : List_Id;
1410 Alts : List_Id;
1411 V : Node_Id;
1412 DC : Node_Id;
1413 DCH : List_Id;
1414 D_Ref : Node_Id;
1415
1416 begin
1417 Result := Make_Field_Attributes (CI);
1418
1419 if Present (VP) then
1420 Alts := New_List;
1421
1422 V := First_Non_Pragma (Variants (VP));
1423 while Present (V) loop
1424 DCH := New_List;
1425
1426 DC := First (Discrete_Choices (V));
1427 while Present (DC) loop
1428 Append_To (DCH, New_Copy_Tree (DC));
1429 Next (DC);
1430 end loop;
1431
1432 Append_To (Alts,
1433 Make_Case_Statement_Alternative (Loc,
1434 Discrete_Choices => DCH,
1435 Statements =>
1436 Make_Component_List_Attributes (Component_List (V))));
1437 Next_Non_Pragma (V);
1438 end loop;
1439
1440 -- Note: in the following, we make sure that we use new occurrence
1441 -- of for the selector, since there are cases in which we make a
1442 -- reference to a hidden discriminant that is not visible.
1443
1444 -- If the enclosing record is an unchecked_union, we use the
1445 -- default expressions for the discriminant (it must exist)
1446 -- because we cannot generate a reference to it, given that
1447 -- it is not stored.
1448
1449 if Is_Unchecked_Union (Scope (Entity (Name (VP)))) then
1450 D_Ref :=
1451 New_Copy_Tree
1452 (Discriminant_Default_Value (Entity (Name (VP))));
1453 else
1454 D_Ref :=
1455 Make_Selected_Component (Loc,
1456 Prefix => Make_Identifier (Loc, Name_V),
1457 Selector_Name =>
1458 New_Occurrence_Of (Entity (Name (VP)), Loc));
1459 end if;
1460
1461 Append_To (Result,
1462 Make_Case_Statement (Loc,
1463 Expression => D_Ref,
1464 Alternatives => Alts));
1465 end if;
1466
1467 return Result;
1468 end Make_Component_List_Attributes;
1469
1470 --------------------------
1471 -- Make_Field_Attribute --
1472 --------------------------
1473
1474 function Make_Field_Attribute (C : Entity_Id) return Node_Id is
1475 Field_Typ : constant Entity_Id := Stream_Base_Type (Etype (C));
1476
1477 TSS_Names : constant array (Name_Input .. Name_Write) of
1478 TSS_Name_Type :=
1479 (Name_Read => TSS_Stream_Read,
1480 Name_Write => TSS_Stream_Write,
1481 Name_Input => TSS_Stream_Input,
1482 Name_Output => TSS_Stream_Output,
1483 others => TSS_Null);
1484 pragma Assert (TSS_Names (Nam) /= TSS_Null);
1485
1486 begin
1487 if In_Limited_Extension
1488 and then Is_Limited_Type (Field_Typ)
1489 and then No (Find_Inherited_TSS (Field_Typ, TSS_Names (Nam)))
1490 then
1491 -- The declaration is illegal per 13.13.2(9/1), and this is
1492 -- enforced in Exp_Ch3.Check_Stream_Attributes. Keep the caller
1493 -- happy by returning a null statement.
1494
1495 return Make_Null_Statement (Loc);
1496 end if;
1497
1498 return
1499 Make_Attribute_Reference (Loc,
1500 Prefix => New_Occurrence_Of (Field_Typ, Loc),
1501 Attribute_Name => Nam,
1502 Expressions => New_List (
1503 Make_Identifier (Loc, Name_S),
1504 Make_Selected_Component (Loc,
1505 Prefix => Make_Identifier (Loc, Name_V),
1506 Selector_Name => New_Occurrence_Of (C, Loc))));
1507 end Make_Field_Attribute;
1508
1509 ---------------------------
1510 -- Make_Field_Attributes --
1511 ---------------------------
1512
1513 function Make_Field_Attributes (Clist : List_Id) return List_Id is
1514 Item : Node_Id;
1515 Result : List_Id;
1516
1517 begin
1518 Result := New_List;
1519
1520 if Present (Clist) then
1521 Item := First (Clist);
1522
1523 -- Loop through components, skipping all internal components,
1524 -- which are not part of the value (e.g. _Tag), except that we
1525 -- don't skip the _Parent, since we do want to process that
1526 -- recursively. If _Parent is an interface type, being abstract
1527 -- with no components there is no need to handle it.
1528
1529 while Present (Item) loop
1530 if Nkind (Item) = N_Component_Declaration
1531 and then
1532 ((Chars (Defining_Identifier (Item)) = Name_uParent
1533 and then not Is_Interface
1534 (Etype (Defining_Identifier (Item))))
1535 or else
1536 not Is_Internal_Name (Chars (Defining_Identifier (Item))))
1537 then
1538 Append_To
1539 (Result,
1540 Make_Field_Attribute (Defining_Identifier (Item)));
1541 end if;
1542
1543 Next (Item);
1544 end loop;
1545 end if;
1546
1547 return Result;
1548 end Make_Field_Attributes;
1549
1550 -- Start of processing for Build_Record_Read_Write_Procedure
1551
1552 begin
1553 -- For the protected type case, use corresponding record
1554
1555 if Is_Protected_Type (Typ) then
1556 Typt := Corresponding_Record_Type (Typ);
1557 else
1558 Typt := Typ;
1559 end if;
1560
1561 -- Note that we do nothing with the discriminants, since Read and
1562 -- Write do not read or write the discriminant values. All handling
1563 -- of discriminants occurs in the Input and Output subprograms.
1564
1565 Rdef := Type_Definition
1566 (Declaration_Node (Base_Type (Underlying_Type (Typt))));
1567 Stms := Empty_List;
1568
1569 -- In record extension case, the fields we want, including the _Parent
1570 -- field representing the parent type, are to be found in the extension.
1571 -- Note that we will naturally process the _Parent field using the type
1572 -- of the parent, and hence its stream attributes, which is appropriate.
1573
1574 if Nkind (Rdef) = N_Derived_Type_Definition then
1575 Rdef := Record_Extension_Part (Rdef);
1576
1577 if Is_Limited_Type (Typt) then
1578 In_Limited_Extension := True;
1579 end if;
1580 end if;
1581
1582 if Present (Component_List (Rdef)) then
1583 Append_List_To (Stms,
1584 Make_Component_List_Attributes (Component_List (Rdef)));
1585 end if;
1586
1587 Build_Stream_Procedure
1588 (Loc, Typ, Decl, Pnam, Stms, Nam = Name_Read);
1589 end Build_Record_Read_Write_Procedure;
1590
1591 ----------------------------------
1592 -- Build_Record_Write_Procedure --
1593 ----------------------------------
1594
1595 procedure Build_Record_Write_Procedure
1596 (Loc : Source_Ptr;
1597 Typ : Entity_Id;
1598 Decl : out Node_Id;
1599 Pnam : out Entity_Id)
1600 is
1601 begin
1602 Pnam := Make_Stream_Subprogram_Name (Loc, Typ, TSS_Stream_Write);
1603 Build_Record_Read_Write_Procedure (Loc, Typ, Decl, Pnam, Name_Write);
1604 end Build_Record_Write_Procedure;
1605
1606 -------------------------------
1607 -- Build_Stream_Attr_Profile --
1608 -------------------------------
1609
1610 function Build_Stream_Attr_Profile
1611 (Loc : Source_Ptr;
1612 Typ : Entity_Id;
1613 Nam : TSS_Name_Type) return List_Id
1614 is
1615 Profile : List_Id;
1616
1617 begin
1618 -- (Ada 2005: AI-441): Set the null-excluding attribute because it has
1619 -- no semantic meaning in Ada 95 but it is a requirement in Ada 2005.
1620
1621 Profile := New_List (
1622 Make_Parameter_Specification (Loc,
1623 Defining_Identifier => Make_Defining_Identifier (Loc, Name_S),
1624 Parameter_Type =>
1625 Make_Access_Definition (Loc,
1626 Null_Exclusion_Present => True,
1627 Subtype_Mark => New_Occurrence_Of (
1628 Class_Wide_Type (RTE (RE_Root_Stream_Type)), Loc))));
1629
1630 if Nam /= TSS_Stream_Input then
1631 Append_To (Profile,
1632 Make_Parameter_Specification (Loc,
1633 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
1634 Out_Present => (Nam = TSS_Stream_Read),
1635 Parameter_Type => New_Occurrence_Of (Typ, Loc)));
1636 end if;
1637
1638 return Profile;
1639 end Build_Stream_Attr_Profile;
1640
1641 ---------------------------
1642 -- Build_Stream_Function --
1643 ---------------------------
1644
1645 procedure Build_Stream_Function
1646 (Loc : Source_Ptr;
1647 Typ : Entity_Id;
1648 Decl : out Node_Id;
1649 Fnam : Entity_Id;
1650 Decls : List_Id;
1651 Stms : List_Id)
1652 is
1653 Spec : Node_Id;
1654
1655 begin
1656 -- Construct function specification
1657
1658 -- (Ada 2005: AI-441): Set the null-excluding attribute because it has
1659 -- no semantic meaning in Ada 95 but it is a requirement in Ada 2005.
1660
1661 Spec :=
1662 Make_Function_Specification (Loc,
1663 Defining_Unit_Name => Fnam,
1664
1665 Parameter_Specifications => New_List (
1666 Make_Parameter_Specification (Loc,
1667 Defining_Identifier => Make_Defining_Identifier (Loc, Name_S),
1668 Parameter_Type =>
1669 Make_Access_Definition (Loc,
1670 Null_Exclusion_Present => True,
1671 Subtype_Mark =>
1672 New_Occurrence_Of
1673 (Class_Wide_Type (RTE (RE_Root_Stream_Type)), Loc)))),
1674
1675 Result_Definition => New_Occurrence_Of (Typ, Loc));
1676
1677 Decl :=
1678 Make_Subprogram_Body (Loc,
1679 Specification => Spec,
1680 Declarations => Decls,
1681 Handled_Statement_Sequence =>
1682 Make_Handled_Sequence_Of_Statements (Loc,
1683 Statements => Stms));
1684 end Build_Stream_Function;
1685
1686 ----------------------------
1687 -- Build_Stream_Procedure --
1688 ----------------------------
1689
1690 procedure Build_Stream_Procedure
1691 (Loc : Source_Ptr;
1692 Typ : Entity_Id;
1693 Decl : out Node_Id;
1694 Pnam : Entity_Id;
1695 Stms : List_Id;
1696 Outp : Boolean)
1697 is
1698 Spec : Node_Id;
1699
1700 begin
1701 -- Construct procedure specification
1702
1703 -- (Ada 2005: AI-441): Set the null-excluding attribute because it has
1704 -- no semantic meaning in Ada 95 but it is a requirement in Ada 2005.
1705
1706 Spec :=
1707 Make_Procedure_Specification (Loc,
1708 Defining_Unit_Name => Pnam,
1709
1710 Parameter_Specifications => New_List (
1711 Make_Parameter_Specification (Loc,
1712 Defining_Identifier => Make_Defining_Identifier (Loc, Name_S),
1713 Parameter_Type =>
1714 Make_Access_Definition (Loc,
1715 Null_Exclusion_Present => True,
1716 Subtype_Mark =>
1717 New_Occurrence_Of
1718 (Class_Wide_Type (RTE (RE_Root_Stream_Type)), Loc))),
1719
1720 Make_Parameter_Specification (Loc,
1721 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
1722 Out_Present => Outp,
1723 Parameter_Type => New_Occurrence_Of (Typ, Loc))));
1724
1725 Decl :=
1726 Make_Subprogram_Body (Loc,
1727 Specification => Spec,
1728 Declarations => Empty_List,
1729 Handled_Statement_Sequence =>
1730 Make_Handled_Sequence_Of_Statements (Loc,
1731 Statements => Stms));
1732 end Build_Stream_Procedure;
1733
1734 -----------------------------
1735 -- Has_Stream_Standard_Rep --
1736 -----------------------------
1737
1738 function Has_Stream_Standard_Rep (U_Type : Entity_Id) return Boolean is
1739 Siz : Uint;
1740
1741 begin
1742 if Has_Non_Standard_Rep (U_Type) then
1743 return False;
1744 end if;
1745
1746 if Has_Stream_Size_Clause (U_Type) then
1747 Siz := Static_Integer (Expression (Stream_Size_Clause (U_Type)));
1748 else
1749 Siz := Esize (First_Subtype (U_Type));
1750 end if;
1751
1752 return Siz = Esize (Root_Type (U_Type));
1753 end Has_Stream_Standard_Rep;
1754
1755 ---------------------------------
1756 -- Make_Stream_Subprogram_Name --
1757 ---------------------------------
1758
1759 function Make_Stream_Subprogram_Name
1760 (Loc : Source_Ptr;
1761 Typ : Entity_Id;
1762 Nam : TSS_Name_Type) return Entity_Id
1763 is
1764 Sname : Name_Id;
1765
1766 begin
1767 -- For tagged types, we are dealing with a TSS associated with the
1768 -- declaration, so we use the standard primitive function name. For
1769 -- other types, generate a local TSS name since we are generating
1770 -- the subprogram at the point of use.
1771
1772 if Is_Tagged_Type (Typ) then
1773 Sname := Make_TSS_Name (Typ, Nam);
1774 else
1775 Sname := Make_TSS_Name_Local (Typ, Nam);
1776 end if;
1777
1778 return Make_Defining_Identifier (Loc, Sname);
1779 end Make_Stream_Subprogram_Name;
1780
1781 ----------------------
1782 -- Stream_Base_Type --
1783 ----------------------
1784
1785 function Stream_Base_Type (E : Entity_Id) return Entity_Id is
1786 begin
1787 if Is_Array_Type (E)
1788 and then Is_First_Subtype (E)
1789 then
1790 return E;
1791 else
1792 return Base_Type (E);
1793 end if;
1794 end Stream_Base_Type;
1795
1796 end Exp_Strm;