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objc/
[official-gcc.git] / gcc / ada / exp_util.adb
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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- E X P _ U T I L --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2005 Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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 Elists; use Elists;
31 with Errout; use Errout;
32 with Exp_Aggr; use Exp_Aggr;
33 with Exp_Ch7; use Exp_Ch7;
34 with Exp_Ch11; use Exp_Ch11;
35 with Exp_Tss; use Exp_Tss;
36 with Hostparm; use Hostparm;
37 with Inline; use Inline;
38 with Itypes; use Itypes;
39 with Lib; use Lib;
40 with Namet; use Namet;
41 with Nlists; use Nlists;
42 with Nmake; use Nmake;
43 with Opt; use Opt;
44 with Restrict; use Restrict;
45 with Rident; use Rident;
46 with Sem; use Sem;
47 with Sem_Ch8; use Sem_Ch8;
48 with Sem_Eval; use Sem_Eval;
49 with Sem_Res; use Sem_Res;
50 with Sem_Type; use Sem_Type;
51 with Sem_Util; use Sem_Util;
52 with Sinfo; use Sinfo;
53 with Snames; use Snames;
54 with Stand; use Stand;
55 with Stringt; use Stringt;
56 with Targparm; use Targparm;
57 with Tbuild; use Tbuild;
58 with Ttypes; use Ttypes;
59 with Uintp; use Uintp;
60 with Urealp; use Urealp;
61 with Validsw; use Validsw;
62
63 package body Exp_Util is
64
65 -----------------------
66 -- Local Subprograms --
67 -----------------------
68
69 function Build_Task_Array_Image
70 (Loc : Source_Ptr;
71 Id_Ref : Node_Id;
72 A_Type : Entity_Id;
73 Dyn : Boolean := False) return Node_Id;
74 -- Build function to generate the image string for a task that is an
75 -- array component, concatenating the images of each index. To avoid
76 -- storage leaks, the string is built with successive slice assignments.
77 -- The flag Dyn indicates whether this is called for the initialization
78 -- procedure of an array of tasks, or for the name of a dynamically
79 -- created task that is assigned to an indexed component.
80
81 function Build_Task_Image_Function
82 (Loc : Source_Ptr;
83 Decls : List_Id;
84 Stats : List_Id;
85 Res : Entity_Id) return Node_Id;
86 -- Common processing for Task_Array_Image and Task_Record_Image.
87 -- Build function body that computes image.
88
89 procedure Build_Task_Image_Prefix
90 (Loc : Source_Ptr;
91 Len : out Entity_Id;
92 Res : out Entity_Id;
93 Pos : out Entity_Id;
94 Prefix : Entity_Id;
95 Sum : Node_Id;
96 Decls : in out List_Id;
97 Stats : in out List_Id);
98 -- Common processing for Task_Array_Image and Task_Record_Image.
99 -- Create local variables and assign prefix of name to result string.
100
101 function Build_Task_Record_Image
102 (Loc : Source_Ptr;
103 Id_Ref : Node_Id;
104 Dyn : Boolean := False) return Node_Id;
105 -- Build function to generate the image string for a task that is a
106 -- record component. Concatenate name of variable with that of selector.
107 -- The flag Dyn indicates whether this is called for the initialization
108 -- procedure of record with task components, or for a dynamically
109 -- created task that is assigned to a selected component.
110
111 procedure Find_Interface_Tag
112 (T : Entity_Id;
113 Iface : Entity_Id;
114 Iface_Tag : out Entity_Id;
115 Iface_ADT : out Entity_Id);
116 -- Ada 2005 (AI-251): Subsidiary procedure to Find_Interface_ADT and
117 -- Find_Interface_Tag. Given a type T implementing the interface,
118 -- returns the corresponding Tag and Access_Disp_Table entities.
119
120 function Make_CW_Equivalent_Type
121 (T : Entity_Id;
122 E : Node_Id) return Entity_Id;
123 -- T is a class-wide type entity, E is the initial expression node that
124 -- constrains T in case such as: " X: T := E" or "new T'(E)"
125 -- This function returns the entity of the Equivalent type and inserts
126 -- on the fly the necessary declaration such as:
127 --
128 -- type anon is record
129 -- _parent : Root_Type (T); constrained with E discriminants (if any)
130 -- Extension : String (1 .. expr to match size of E);
131 -- end record;
132 --
133 -- This record is compatible with any object of the class of T thanks
134 -- to the first field and has the same size as E thanks to the second.
135
136 function Make_Literal_Range
137 (Loc : Source_Ptr;
138 Literal_Typ : Entity_Id) return Node_Id;
139 -- Produce a Range node whose bounds are:
140 -- Low_Bound (Literal_Type) ..
141 -- Low_Bound (Literal_Type) + Length (Literal_Typ) - 1
142 -- this is used for expanding declarations like X : String := "sdfgdfg";
143
144 function New_Class_Wide_Subtype
145 (CW_Typ : Entity_Id;
146 N : Node_Id) return Entity_Id;
147 -- Create an implicit subtype of CW_Typ attached to node N
148
149 ----------------------
150 -- Adjust_Condition --
151 ----------------------
152
153 procedure Adjust_Condition (N : Node_Id) is
154 begin
155 if No (N) then
156 return;
157 end if;
158
159 declare
160 Loc : constant Source_Ptr := Sloc (N);
161 T : constant Entity_Id := Etype (N);
162 Ti : Entity_Id;
163
164 begin
165 -- For now, we simply ignore a call where the argument has no
166 -- type (probably case of unanalyzed condition), or has a type
167 -- that is not Boolean. This is because this is a pretty marginal
168 -- piece of functionality, and violations of these rules are
169 -- likely to be truly marginal (how much code uses Fortran Logical
170 -- as the barrier to a protected entry?) and we do not want to
171 -- blow up existing programs. We can change this to an assertion
172 -- after 3.12a is released ???
173
174 if No (T) or else not Is_Boolean_Type (T) then
175 return;
176 end if;
177
178 -- Apply validity checking if needed
179
180 if Validity_Checks_On and Validity_Check_Tests then
181 Ensure_Valid (N);
182 end if;
183
184 -- Immediate return if standard boolean, the most common case,
185 -- where nothing needs to be done.
186
187 if Base_Type (T) = Standard_Boolean then
188 return;
189 end if;
190
191 -- Case of zero/non-zero semantics or non-standard enumeration
192 -- representation. In each case, we rewrite the node as:
193
194 -- ityp!(N) /= False'Enum_Rep
195
196 -- where ityp is an integer type with large enough size to hold
197 -- any value of type T.
198
199 if Nonzero_Is_True (T) or else Has_Non_Standard_Rep (T) then
200 if Esize (T) <= Esize (Standard_Integer) then
201 Ti := Standard_Integer;
202 else
203 Ti := Standard_Long_Long_Integer;
204 end if;
205
206 Rewrite (N,
207 Make_Op_Ne (Loc,
208 Left_Opnd => Unchecked_Convert_To (Ti, N),
209 Right_Opnd =>
210 Make_Attribute_Reference (Loc,
211 Attribute_Name => Name_Enum_Rep,
212 Prefix =>
213 New_Occurrence_Of (First_Literal (T), Loc))));
214 Analyze_And_Resolve (N, Standard_Boolean);
215
216 else
217 Rewrite (N, Convert_To (Standard_Boolean, N));
218 Analyze_And_Resolve (N, Standard_Boolean);
219 end if;
220 end;
221 end Adjust_Condition;
222
223 ------------------------
224 -- Adjust_Result_Type --
225 ------------------------
226
227 procedure Adjust_Result_Type (N : Node_Id; T : Entity_Id) is
228 begin
229 -- Ignore call if current type is not Standard.Boolean
230
231 if Etype (N) /= Standard_Boolean then
232 return;
233 end if;
234
235 -- If result is already of correct type, nothing to do. Note that
236 -- this will get the most common case where everything has a type
237 -- of Standard.Boolean.
238
239 if Base_Type (T) = Standard_Boolean then
240 return;
241
242 else
243 declare
244 KP : constant Node_Kind := Nkind (Parent (N));
245
246 begin
247 -- If result is to be used as a Condition in the syntax, no need
248 -- to convert it back, since if it was changed to Standard.Boolean
249 -- using Adjust_Condition, that is just fine for this usage.
250
251 if KP in N_Raise_xxx_Error or else KP in N_Has_Condition then
252 return;
253
254 -- If result is an operand of another logical operation, no need
255 -- to reset its type, since Standard.Boolean is just fine, and
256 -- such operations always do Adjust_Condition on their operands.
257
258 elsif KP in N_Op_Boolean
259 or else KP = N_And_Then
260 or else KP = N_Or_Else
261 or else KP = N_Op_Not
262 then
263 return;
264
265 -- Otherwise we perform a conversion from the current type,
266 -- which must be Standard.Boolean, to the desired type.
267
268 else
269 Set_Analyzed (N);
270 Rewrite (N, Convert_To (T, N));
271 Analyze_And_Resolve (N, T);
272 end if;
273 end;
274 end if;
275 end Adjust_Result_Type;
276
277 --------------------------
278 -- Append_Freeze_Action --
279 --------------------------
280
281 procedure Append_Freeze_Action (T : Entity_Id; N : Node_Id) is
282 Fnode : Node_Id := Freeze_Node (T);
283
284 begin
285 Ensure_Freeze_Node (T);
286 Fnode := Freeze_Node (T);
287
288 if not Present (Actions (Fnode)) then
289 Set_Actions (Fnode, New_List);
290 end if;
291
292 Append (N, Actions (Fnode));
293 end Append_Freeze_Action;
294
295 ---------------------------
296 -- Append_Freeze_Actions --
297 ---------------------------
298
299 procedure Append_Freeze_Actions (T : Entity_Id; L : List_Id) is
300 Fnode : constant Node_Id := Freeze_Node (T);
301
302 begin
303 if No (L) then
304 return;
305
306 else
307 if No (Actions (Fnode)) then
308 Set_Actions (Fnode, L);
309
310 else
311 Append_List (L, Actions (Fnode));
312 end if;
313
314 end if;
315 end Append_Freeze_Actions;
316
317 ------------------------
318 -- Build_Runtime_Call --
319 ------------------------
320
321 function Build_Runtime_Call (Loc : Source_Ptr; RE : RE_Id) return Node_Id is
322 begin
323 -- If entity is not available, we can skip making the call (this avoids
324 -- junk duplicated error messages in a number of cases).
325
326 if not RTE_Available (RE) then
327 return Make_Null_Statement (Loc);
328 else
329 return
330 Make_Procedure_Call_Statement (Loc,
331 Name => New_Reference_To (RTE (RE), Loc));
332 end if;
333 end Build_Runtime_Call;
334
335 ----------------------------
336 -- Build_Task_Array_Image --
337 ----------------------------
338
339 -- This function generates the body for a function that constructs the
340 -- image string for a task that is an array component. The function is
341 -- local to the init proc for the array type, and is called for each one
342 -- of the components. The constructed image has the form of an indexed
343 -- component, whose prefix is the outer variable of the array type.
344 -- The n-dimensional array type has known indices Index, Index2...
345 -- Id_Ref is an indexed component form created by the enclosing init proc.
346 -- Its successive indices are Val1, Val2,.. which are the loop variables
347 -- in the loops that call the individual task init proc on each component.
348
349 -- The generated function has the following structure:
350
351 -- function F return String is
352 -- Pref : string renames Task_Name;
353 -- T1 : String := Index1'Image (Val1);
354 -- ...
355 -- Tn : String := indexn'image (Valn);
356 -- Len : Integer := T1'Length + ... + Tn'Length + n + 1;
357 -- -- Len includes commas and the end parentheses.
358 -- Res : String (1..Len);
359 -- Pos : Integer := Pref'Length;
360 --
361 -- begin
362 -- Res (1 .. Pos) := Pref;
363 -- Pos := Pos + 1;
364 -- Res (Pos) := '(';
365 -- Pos := Pos + 1;
366 -- Res (Pos .. Pos + T1'Length - 1) := T1;
367 -- Pos := Pos + T1'Length;
368 -- Res (Pos) := '.';
369 -- Pos := Pos + 1;
370 -- ...
371 -- Res (Pos .. Pos + Tn'Length - 1) := Tn;
372 -- Res (Len) := ')';
373 --
374 -- return Res;
375 -- end F;
376 --
377 -- Needless to say, multidimensional arrays of tasks are rare enough
378 -- that the bulkiness of this code is not really a concern.
379
380 function Build_Task_Array_Image
381 (Loc : Source_Ptr;
382 Id_Ref : Node_Id;
383 A_Type : Entity_Id;
384 Dyn : Boolean := False) return Node_Id
385 is
386 Dims : constant Nat := Number_Dimensions (A_Type);
387 -- Number of dimensions for array of tasks
388
389 Temps : array (1 .. Dims) of Entity_Id;
390 -- Array of temporaries to hold string for each index
391
392 Indx : Node_Id;
393 -- Index expression
394
395 Len : Entity_Id;
396 -- Total length of generated name
397
398 Pos : Entity_Id;
399 -- Running index for substring assignments
400
401 Pref : Entity_Id;
402 -- Name of enclosing variable, prefix of resulting name
403
404 Res : Entity_Id;
405 -- String to hold result
406
407 Val : Node_Id;
408 -- Value of successive indices
409
410 Sum : Node_Id;
411 -- Expression to compute total size of string
412
413 T : Entity_Id;
414 -- Entity for name at one index position
415
416 Decls : List_Id := New_List;
417 Stats : List_Id := New_List;
418
419 begin
420 Pref := Make_Defining_Identifier (Loc, New_Internal_Name ('P'));
421
422 -- For a dynamic task, the name comes from the target variable.
423 -- For a static one it is a formal of the enclosing init proc.
424
425 if Dyn then
426 Get_Name_String (Chars (Entity (Prefix (Id_Ref))));
427 Append_To (Decls,
428 Make_Object_Declaration (Loc,
429 Defining_Identifier => Pref,
430 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
431 Expression =>
432 Make_String_Literal (Loc,
433 Strval => String_From_Name_Buffer)));
434
435 else
436 Append_To (Decls,
437 Make_Object_Renaming_Declaration (Loc,
438 Defining_Identifier => Pref,
439 Subtype_Mark => New_Occurrence_Of (Standard_String, Loc),
440 Name => Make_Identifier (Loc, Name_uTask_Name)));
441 end if;
442
443 Indx := First_Index (A_Type);
444 Val := First (Expressions (Id_Ref));
445
446 for J in 1 .. Dims loop
447 T := Make_Defining_Identifier (Loc, New_Internal_Name ('T'));
448 Temps (J) := T;
449
450 Append_To (Decls,
451 Make_Object_Declaration (Loc,
452 Defining_Identifier => T,
453 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
454 Expression =>
455 Make_Attribute_Reference (Loc,
456 Attribute_Name => Name_Image,
457 Prefix =>
458 New_Occurrence_Of (Etype (Indx), Loc),
459 Expressions => New_List (
460 New_Copy_Tree (Val)))));
461
462 Next_Index (Indx);
463 Next (Val);
464 end loop;
465
466 Sum := Make_Integer_Literal (Loc, Dims + 1);
467
468 Sum :=
469 Make_Op_Add (Loc,
470 Left_Opnd => Sum,
471 Right_Opnd =>
472 Make_Attribute_Reference (Loc,
473 Attribute_Name => Name_Length,
474 Prefix =>
475 New_Occurrence_Of (Pref, Loc),
476 Expressions => New_List (Make_Integer_Literal (Loc, 1))));
477
478 for J in 1 .. Dims loop
479 Sum :=
480 Make_Op_Add (Loc,
481 Left_Opnd => Sum,
482 Right_Opnd =>
483 Make_Attribute_Reference (Loc,
484 Attribute_Name => Name_Length,
485 Prefix =>
486 New_Occurrence_Of (Temps (J), Loc),
487 Expressions => New_List (Make_Integer_Literal (Loc, 1))));
488 end loop;
489
490 Build_Task_Image_Prefix (Loc, Len, Res, Pos, Pref, Sum, Decls, Stats);
491
492 Set_Character_Literal_Name (Char_Code (Character'Pos ('(')));
493
494 Append_To (Stats,
495 Make_Assignment_Statement (Loc,
496 Name => Make_Indexed_Component (Loc,
497 Prefix => New_Occurrence_Of (Res, Loc),
498 Expressions => New_List (New_Occurrence_Of (Pos, Loc))),
499 Expression =>
500 Make_Character_Literal (Loc,
501 Chars => Name_Find,
502 Char_Literal_Value =>
503 UI_From_Int (Character'Pos ('(')))));
504
505 Append_To (Stats,
506 Make_Assignment_Statement (Loc,
507 Name => New_Occurrence_Of (Pos, Loc),
508 Expression =>
509 Make_Op_Add (Loc,
510 Left_Opnd => New_Occurrence_Of (Pos, Loc),
511 Right_Opnd => Make_Integer_Literal (Loc, 1))));
512
513 for J in 1 .. Dims loop
514
515 Append_To (Stats,
516 Make_Assignment_Statement (Loc,
517 Name => Make_Slice (Loc,
518 Prefix => New_Occurrence_Of (Res, Loc),
519 Discrete_Range =>
520 Make_Range (Loc,
521 Low_Bound => New_Occurrence_Of (Pos, Loc),
522 High_Bound => Make_Op_Subtract (Loc,
523 Left_Opnd =>
524 Make_Op_Add (Loc,
525 Left_Opnd => New_Occurrence_Of (Pos, Loc),
526 Right_Opnd =>
527 Make_Attribute_Reference (Loc,
528 Attribute_Name => Name_Length,
529 Prefix =>
530 New_Occurrence_Of (Temps (J), Loc),
531 Expressions =>
532 New_List (Make_Integer_Literal (Loc, 1)))),
533 Right_Opnd => Make_Integer_Literal (Loc, 1)))),
534
535 Expression => New_Occurrence_Of (Temps (J), Loc)));
536
537 if J < Dims then
538 Append_To (Stats,
539 Make_Assignment_Statement (Loc,
540 Name => New_Occurrence_Of (Pos, Loc),
541 Expression =>
542 Make_Op_Add (Loc,
543 Left_Opnd => New_Occurrence_Of (Pos, Loc),
544 Right_Opnd =>
545 Make_Attribute_Reference (Loc,
546 Attribute_Name => Name_Length,
547 Prefix => New_Occurrence_Of (Temps (J), Loc),
548 Expressions =>
549 New_List (Make_Integer_Literal (Loc, 1))))));
550
551 Set_Character_Literal_Name (Char_Code (Character'Pos (',')));
552
553 Append_To (Stats,
554 Make_Assignment_Statement (Loc,
555 Name => Make_Indexed_Component (Loc,
556 Prefix => New_Occurrence_Of (Res, Loc),
557 Expressions => New_List (New_Occurrence_Of (Pos, Loc))),
558 Expression =>
559 Make_Character_Literal (Loc,
560 Chars => Name_Find,
561 Char_Literal_Value =>
562 UI_From_Int (Character'Pos (',')))));
563
564 Append_To (Stats,
565 Make_Assignment_Statement (Loc,
566 Name => New_Occurrence_Of (Pos, Loc),
567 Expression =>
568 Make_Op_Add (Loc,
569 Left_Opnd => New_Occurrence_Of (Pos, Loc),
570 Right_Opnd => Make_Integer_Literal (Loc, 1))));
571 end if;
572 end loop;
573
574 Set_Character_Literal_Name (Char_Code (Character'Pos (')')));
575
576 Append_To (Stats,
577 Make_Assignment_Statement (Loc,
578 Name => Make_Indexed_Component (Loc,
579 Prefix => New_Occurrence_Of (Res, Loc),
580 Expressions => New_List (New_Occurrence_Of (Len, Loc))),
581 Expression =>
582 Make_Character_Literal (Loc,
583 Chars => Name_Find,
584 Char_Literal_Value =>
585 UI_From_Int (Character'Pos (')')))));
586 return Build_Task_Image_Function (Loc, Decls, Stats, Res);
587 end Build_Task_Array_Image;
588
589 ----------------------------
590 -- Build_Task_Image_Decls --
591 ----------------------------
592
593 function Build_Task_Image_Decls
594 (Loc : Source_Ptr;
595 Id_Ref : Node_Id;
596 A_Type : Entity_Id) return List_Id
597 is
598 Decls : constant List_Id := New_List;
599 T_Id : Entity_Id := Empty;
600 Decl : Node_Id;
601 Expr : Node_Id := Empty;
602 Fun : Node_Id := Empty;
603 Is_Dyn : constant Boolean :=
604 Nkind (Parent (Id_Ref)) = N_Assignment_Statement
605 and then
606 Nkind (Expression (Parent (Id_Ref))) = N_Allocator;
607
608 begin
609 -- If Discard_Names or No_Implicit_Heap_Allocations are in effect,
610 -- generate a dummy declaration only.
611
612 if Restriction_Active (No_Implicit_Heap_Allocations)
613 or else Global_Discard_Names
614 then
615 T_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('J'));
616 Name_Len := 0;
617
618 return
619 New_List (
620 Make_Object_Declaration (Loc,
621 Defining_Identifier => T_Id,
622 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
623 Expression =>
624 Make_String_Literal (Loc,
625 Strval => String_From_Name_Buffer)));
626
627 else
628 if Nkind (Id_Ref) = N_Identifier
629 or else Nkind (Id_Ref) = N_Defining_Identifier
630 then
631 -- For a simple variable, the image of the task is built from
632 -- the name of the variable. To avoid possible conflict with
633 -- the anonymous type created for a single protected object,
634 -- add a numeric suffix.
635
636 T_Id :=
637 Make_Defining_Identifier (Loc,
638 New_External_Name (Chars (Id_Ref), 'T', 1));
639
640 Get_Name_String (Chars (Id_Ref));
641
642 Expr :=
643 Make_String_Literal (Loc,
644 Strval => String_From_Name_Buffer);
645
646 elsif Nkind (Id_Ref) = N_Selected_Component then
647 T_Id :=
648 Make_Defining_Identifier (Loc,
649 New_External_Name (Chars (Selector_Name (Id_Ref)), 'T'));
650 Fun := Build_Task_Record_Image (Loc, Id_Ref, Is_Dyn);
651
652 elsif Nkind (Id_Ref) = N_Indexed_Component then
653 T_Id :=
654 Make_Defining_Identifier (Loc,
655 New_External_Name (Chars (A_Type), 'N'));
656
657 Fun := Build_Task_Array_Image (Loc, Id_Ref, A_Type, Is_Dyn);
658 end if;
659 end if;
660
661 if Present (Fun) then
662 Append (Fun, Decls);
663 Expr := Make_Function_Call (Loc,
664 Name => New_Occurrence_Of (Defining_Entity (Fun), Loc));
665 end if;
666
667 Decl := Make_Object_Declaration (Loc,
668 Defining_Identifier => T_Id,
669 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
670 Constant_Present => True,
671 Expression => Expr);
672
673 Append (Decl, Decls);
674 return Decls;
675 end Build_Task_Image_Decls;
676
677 -------------------------------
678 -- Build_Task_Image_Function --
679 -------------------------------
680
681 function Build_Task_Image_Function
682 (Loc : Source_Ptr;
683 Decls : List_Id;
684 Stats : List_Id;
685 Res : Entity_Id) return Node_Id
686 is
687 Spec : Node_Id;
688
689 begin
690 Append_To (Stats,
691 Make_Return_Statement (Loc,
692 Expression => New_Occurrence_Of (Res, Loc)));
693
694 Spec := Make_Function_Specification (Loc,
695 Defining_Unit_Name =>
696 Make_Defining_Identifier (Loc, New_Internal_Name ('F')),
697 Subtype_Mark => New_Occurrence_Of (Standard_String, Loc));
698
699 -- Calls to 'Image use the secondary stack, which must be cleaned
700 -- up after the task name is built.
701
702 Set_Uses_Sec_Stack (Defining_Unit_Name (Spec));
703
704 return Make_Subprogram_Body (Loc,
705 Specification => Spec,
706 Declarations => Decls,
707 Handled_Statement_Sequence =>
708 Make_Handled_Sequence_Of_Statements (Loc, Statements => Stats));
709 end Build_Task_Image_Function;
710
711 -----------------------------
712 -- Build_Task_Image_Prefix --
713 -----------------------------
714
715 procedure Build_Task_Image_Prefix
716 (Loc : Source_Ptr;
717 Len : out Entity_Id;
718 Res : out Entity_Id;
719 Pos : out Entity_Id;
720 Prefix : Entity_Id;
721 Sum : Node_Id;
722 Decls : in out List_Id;
723 Stats : in out List_Id)
724 is
725 begin
726 Len := Make_Defining_Identifier (Loc, New_Internal_Name ('L'));
727
728 Append_To (Decls,
729 Make_Object_Declaration (Loc,
730 Defining_Identifier => Len,
731 Object_Definition => New_Occurrence_Of (Standard_Integer, Loc),
732 Expression => Sum));
733
734 Res := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
735
736 Append_To (Decls,
737 Make_Object_Declaration (Loc,
738 Defining_Identifier => Res,
739 Object_Definition =>
740 Make_Subtype_Indication (Loc,
741 Subtype_Mark => New_Occurrence_Of (Standard_String, Loc),
742 Constraint =>
743 Make_Index_Or_Discriminant_Constraint (Loc,
744 Constraints =>
745 New_List (
746 Make_Range (Loc,
747 Low_Bound => Make_Integer_Literal (Loc, 1),
748 High_Bound => New_Occurrence_Of (Len, Loc)))))));
749
750 Pos := Make_Defining_Identifier (Loc, New_Internal_Name ('P'));
751
752 Append_To (Decls,
753 Make_Object_Declaration (Loc,
754 Defining_Identifier => Pos,
755 Object_Definition => New_Occurrence_Of (Standard_Integer, Loc)));
756
757 -- Pos := Prefix'Length;
758
759 Append_To (Stats,
760 Make_Assignment_Statement (Loc,
761 Name => New_Occurrence_Of (Pos, Loc),
762 Expression =>
763 Make_Attribute_Reference (Loc,
764 Attribute_Name => Name_Length,
765 Prefix => New_Occurrence_Of (Prefix, Loc),
766 Expressions =>
767 New_List (Make_Integer_Literal (Loc, 1)))));
768
769 -- Res (1 .. Pos) := Prefix;
770
771 Append_To (Stats,
772 Make_Assignment_Statement (Loc,
773 Name => Make_Slice (Loc,
774 Prefix => New_Occurrence_Of (Res, Loc),
775 Discrete_Range =>
776 Make_Range (Loc,
777 Low_Bound => Make_Integer_Literal (Loc, 1),
778 High_Bound => New_Occurrence_Of (Pos, Loc))),
779
780 Expression => New_Occurrence_Of (Prefix, Loc)));
781
782 Append_To (Stats,
783 Make_Assignment_Statement (Loc,
784 Name => New_Occurrence_Of (Pos, Loc),
785 Expression =>
786 Make_Op_Add (Loc,
787 Left_Opnd => New_Occurrence_Of (Pos, Loc),
788 Right_Opnd => Make_Integer_Literal (Loc, 1))));
789 end Build_Task_Image_Prefix;
790
791 -----------------------------
792 -- Build_Task_Record_Image --
793 -----------------------------
794
795 function Build_Task_Record_Image
796 (Loc : Source_Ptr;
797 Id_Ref : Node_Id;
798 Dyn : Boolean := False) return Node_Id
799 is
800 Len : Entity_Id;
801 -- Total length of generated name
802
803 Pos : Entity_Id;
804 -- Index into result
805
806 Res : Entity_Id;
807 -- String to hold result
808
809 Pref : Entity_Id;
810 -- Name of enclosing variable, prefix of resulting name
811
812 Sum : Node_Id;
813 -- Expression to compute total size of string
814
815 Sel : Entity_Id;
816 -- Entity for selector name
817
818 Decls : List_Id := New_List;
819 Stats : List_Id := New_List;
820
821 begin
822 Pref := Make_Defining_Identifier (Loc, New_Internal_Name ('P'));
823
824 -- For a dynamic task, the name comes from the target variable.
825 -- For a static one it is a formal of the enclosing init proc.
826
827 if Dyn then
828 Get_Name_String (Chars (Entity (Prefix (Id_Ref))));
829 Append_To (Decls,
830 Make_Object_Declaration (Loc,
831 Defining_Identifier => Pref,
832 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
833 Expression =>
834 Make_String_Literal (Loc,
835 Strval => String_From_Name_Buffer)));
836
837 else
838 Append_To (Decls,
839 Make_Object_Renaming_Declaration (Loc,
840 Defining_Identifier => Pref,
841 Subtype_Mark => New_Occurrence_Of (Standard_String, Loc),
842 Name => Make_Identifier (Loc, Name_uTask_Name)));
843 end if;
844
845 Sel := Make_Defining_Identifier (Loc, New_Internal_Name ('S'));
846
847 Get_Name_String (Chars (Selector_Name (Id_Ref)));
848
849 Append_To (Decls,
850 Make_Object_Declaration (Loc,
851 Defining_Identifier => Sel,
852 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
853 Expression =>
854 Make_String_Literal (Loc,
855 Strval => String_From_Name_Buffer)));
856
857 Sum := Make_Integer_Literal (Loc, Nat (Name_Len + 1));
858
859 Sum :=
860 Make_Op_Add (Loc,
861 Left_Opnd => Sum,
862 Right_Opnd =>
863 Make_Attribute_Reference (Loc,
864 Attribute_Name => Name_Length,
865 Prefix =>
866 New_Occurrence_Of (Pref, Loc),
867 Expressions => New_List (Make_Integer_Literal (Loc, 1))));
868
869 Build_Task_Image_Prefix (Loc, Len, Res, Pos, Pref, Sum, Decls, Stats);
870
871 Set_Character_Literal_Name (Char_Code (Character'Pos ('.')));
872
873 -- Res (Pos) := '.';
874
875 Append_To (Stats,
876 Make_Assignment_Statement (Loc,
877 Name => Make_Indexed_Component (Loc,
878 Prefix => New_Occurrence_Of (Res, Loc),
879 Expressions => New_List (New_Occurrence_Of (Pos, Loc))),
880 Expression =>
881 Make_Character_Literal (Loc,
882 Chars => Name_Find,
883 Char_Literal_Value =>
884 UI_From_Int (Character'Pos ('.')))));
885
886 Append_To (Stats,
887 Make_Assignment_Statement (Loc,
888 Name => New_Occurrence_Of (Pos, Loc),
889 Expression =>
890 Make_Op_Add (Loc,
891 Left_Opnd => New_Occurrence_Of (Pos, Loc),
892 Right_Opnd => Make_Integer_Literal (Loc, 1))));
893
894 -- Res (Pos .. Len) := Selector;
895
896 Append_To (Stats,
897 Make_Assignment_Statement (Loc,
898 Name => Make_Slice (Loc,
899 Prefix => New_Occurrence_Of (Res, Loc),
900 Discrete_Range =>
901 Make_Range (Loc,
902 Low_Bound => New_Occurrence_Of (Pos, Loc),
903 High_Bound => New_Occurrence_Of (Len, Loc))),
904 Expression => New_Occurrence_Of (Sel, Loc)));
905
906 return Build_Task_Image_Function (Loc, Decls, Stats, Res);
907 end Build_Task_Record_Image;
908
909 ----------------------------------
910 -- Component_May_Be_Bit_Aligned --
911 ----------------------------------
912
913 function Component_May_Be_Bit_Aligned (Comp : Entity_Id) return Boolean is
914 begin
915 -- If no component clause, then everything is fine, since the
916 -- back end never bit-misaligns by default, even if there is
917 -- a pragma Packed for the record.
918
919 if No (Component_Clause (Comp)) then
920 return False;
921 end if;
922
923 -- It is only array and record types that cause trouble
924
925 if not Is_Record_Type (Etype (Comp))
926 and then not Is_Array_Type (Etype (Comp))
927 then
928 return False;
929
930 -- If we know that we have a small (64 bits or less) record
931 -- or bit-packed array, then everything is fine, since the
932 -- back end can handle these cases correctly.
933
934 elsif Esize (Comp) <= 64
935 and then (Is_Record_Type (Etype (Comp))
936 or else Is_Bit_Packed_Array (Etype (Comp)))
937 then
938 return False;
939
940 -- Otherwise if the component is not byte aligned, we
941 -- know we have the nasty unaligned case.
942
943 elsif Normalized_First_Bit (Comp) /= Uint_0
944 or else Esize (Comp) mod System_Storage_Unit /= Uint_0
945 then
946 return True;
947
948 -- If we are large and byte aligned, then OK at this level
949
950 else
951 return False;
952 end if;
953 end Component_May_Be_Bit_Aligned;
954
955 -------------------------------
956 -- Convert_To_Actual_Subtype --
957 -------------------------------
958
959 procedure Convert_To_Actual_Subtype (Exp : Entity_Id) is
960 Act_ST : Entity_Id;
961
962 begin
963 Act_ST := Get_Actual_Subtype (Exp);
964
965 if Act_ST = Etype (Exp) then
966 return;
967
968 else
969 Rewrite (Exp,
970 Convert_To (Act_ST, Relocate_Node (Exp)));
971 Analyze_And_Resolve (Exp, Act_ST);
972 end if;
973 end Convert_To_Actual_Subtype;
974
975 -----------------------------------
976 -- Current_Sem_Unit_Declarations --
977 -----------------------------------
978
979 function Current_Sem_Unit_Declarations return List_Id is
980 U : Node_Id := Unit (Cunit (Current_Sem_Unit));
981 Decls : List_Id;
982
983 begin
984 -- If the current unit is a package body, locate the visible
985 -- declarations of the package spec.
986
987 if Nkind (U) = N_Package_Body then
988 U := Unit (Library_Unit (Cunit (Current_Sem_Unit)));
989 end if;
990
991 if Nkind (U) = N_Package_Declaration then
992 U := Specification (U);
993 Decls := Visible_Declarations (U);
994
995 if No (Decls) then
996 Decls := New_List;
997 Set_Visible_Declarations (U, Decls);
998 end if;
999
1000 else
1001 Decls := Declarations (U);
1002
1003 if No (Decls) then
1004 Decls := New_List;
1005 Set_Declarations (U, Decls);
1006 end if;
1007 end if;
1008
1009 return Decls;
1010 end Current_Sem_Unit_Declarations;
1011
1012 -----------------------
1013 -- Duplicate_Subexpr --
1014 -----------------------
1015
1016 function Duplicate_Subexpr
1017 (Exp : Node_Id;
1018 Name_Req : Boolean := False) return Node_Id
1019 is
1020 begin
1021 Remove_Side_Effects (Exp, Name_Req);
1022 return New_Copy_Tree (Exp);
1023 end Duplicate_Subexpr;
1024
1025 ---------------------------------
1026 -- Duplicate_Subexpr_No_Checks --
1027 ---------------------------------
1028
1029 function Duplicate_Subexpr_No_Checks
1030 (Exp : Node_Id;
1031 Name_Req : Boolean := False) return Node_Id
1032 is
1033 New_Exp : Node_Id;
1034
1035 begin
1036 Remove_Side_Effects (Exp, Name_Req);
1037 New_Exp := New_Copy_Tree (Exp);
1038 Remove_Checks (New_Exp);
1039 return New_Exp;
1040 end Duplicate_Subexpr_No_Checks;
1041
1042 -----------------------------------
1043 -- Duplicate_Subexpr_Move_Checks --
1044 -----------------------------------
1045
1046 function Duplicate_Subexpr_Move_Checks
1047 (Exp : Node_Id;
1048 Name_Req : Boolean := False) return Node_Id
1049 is
1050 New_Exp : Node_Id;
1051
1052 begin
1053 Remove_Side_Effects (Exp, Name_Req);
1054 New_Exp := New_Copy_Tree (Exp);
1055 Remove_Checks (Exp);
1056 return New_Exp;
1057 end Duplicate_Subexpr_Move_Checks;
1058
1059 --------------------
1060 -- Ensure_Defined --
1061 --------------------
1062
1063 procedure Ensure_Defined (Typ : Entity_Id; N : Node_Id) is
1064 IR : Node_Id;
1065 P : Node_Id;
1066
1067 begin
1068 if Is_Itype (Typ) then
1069 IR := Make_Itype_Reference (Sloc (N));
1070 Set_Itype (IR, Typ);
1071
1072 if not In_Open_Scopes (Scope (Typ))
1073 and then Is_Subprogram (Current_Scope)
1074 and then Scope (Current_Scope) /= Standard_Standard
1075 then
1076 -- Insert node in front of subprogram, to avoid scope anomalies
1077 -- in gigi.
1078
1079 P := Parent (N);
1080 while Present (P)
1081 and then Nkind (P) /= N_Subprogram_Body
1082 loop
1083 P := Parent (P);
1084 end loop;
1085
1086 if Present (P) then
1087 Insert_Action (P, IR);
1088 else
1089 Insert_Action (N, IR);
1090 end if;
1091
1092 else
1093 Insert_Action (N, IR);
1094 end if;
1095 end if;
1096 end Ensure_Defined;
1097
1098 ---------------------
1099 -- Evolve_And_Then --
1100 ---------------------
1101
1102 procedure Evolve_And_Then (Cond : in out Node_Id; Cond1 : Node_Id) is
1103 begin
1104 if No (Cond) then
1105 Cond := Cond1;
1106 else
1107 Cond :=
1108 Make_And_Then (Sloc (Cond1),
1109 Left_Opnd => Cond,
1110 Right_Opnd => Cond1);
1111 end if;
1112 end Evolve_And_Then;
1113
1114 --------------------
1115 -- Evolve_Or_Else --
1116 --------------------
1117
1118 procedure Evolve_Or_Else (Cond : in out Node_Id; Cond1 : Node_Id) is
1119 begin
1120 if No (Cond) then
1121 Cond := Cond1;
1122 else
1123 Cond :=
1124 Make_Or_Else (Sloc (Cond1),
1125 Left_Opnd => Cond,
1126 Right_Opnd => Cond1);
1127 end if;
1128 end Evolve_Or_Else;
1129
1130 ------------------------------
1131 -- Expand_Subtype_From_Expr --
1132 ------------------------------
1133
1134 -- This function is applicable for both static and dynamic allocation of
1135 -- objects which are constrained by an initial expression. Basically it
1136 -- transforms an unconstrained subtype indication into a constrained one.
1137 -- The expression may also be transformed in certain cases in order to
1138 -- avoid multiple evaulation. In the static allocation case, the general
1139 -- scheme is :
1140
1141 -- Val : T := Expr;
1142
1143 -- is transformed into
1144
1145 -- Val : Constrained_Subtype_of_T := Maybe_Modified_Expr;
1146 --
1147 -- Here are the main cases :
1148 --
1149 -- <if Expr is a Slice>
1150 -- Val : T ([Index_Subtype (Expr)]) := Expr;
1151 --
1152 -- <elsif Expr is a String Literal>
1153 -- Val : T (T'First .. T'First + Length (string literal) - 1) := Expr;
1154 --
1155 -- <elsif Expr is Constrained>
1156 -- subtype T is Type_Of_Expr
1157 -- Val : T := Expr;
1158 --
1159 -- <elsif Expr is an entity_name>
1160 -- Val : T (constraints taken from Expr) := Expr;
1161 --
1162 -- <else>
1163 -- type Axxx is access all T;
1164 -- Rval : Axxx := Expr'ref;
1165 -- Val : T (constraints taken from Rval) := Rval.all;
1166
1167 -- ??? note: when the Expression is allocated in the secondary stack
1168 -- we could use it directly instead of copying it by declaring
1169 -- Val : T (...) renames Rval.all
1170
1171 procedure Expand_Subtype_From_Expr
1172 (N : Node_Id;
1173 Unc_Type : Entity_Id;
1174 Subtype_Indic : Node_Id;
1175 Exp : Node_Id)
1176 is
1177 Loc : constant Source_Ptr := Sloc (N);
1178 Exp_Typ : constant Entity_Id := Etype (Exp);
1179 T : Entity_Id;
1180
1181 begin
1182 -- In general we cannot build the subtype if expansion is disabled,
1183 -- because internal entities may not have been defined. However, to
1184 -- avoid some cascaded errors, we try to continue when the expression
1185 -- is an array (or string), because it is safe to compute the bounds.
1186 -- It is in fact required to do so even in a generic context, because
1187 -- there may be constants that depend on bounds of string literal.
1188
1189 if not Expander_Active
1190 and then (No (Etype (Exp))
1191 or else Base_Type (Etype (Exp)) /= Standard_String)
1192 then
1193 return;
1194 end if;
1195
1196 if Nkind (Exp) = N_Slice then
1197 declare
1198 Slice_Type : constant Entity_Id := Etype (First_Index (Exp_Typ));
1199
1200 begin
1201 Rewrite (Subtype_Indic,
1202 Make_Subtype_Indication (Loc,
1203 Subtype_Mark => New_Reference_To (Unc_Type, Loc),
1204 Constraint =>
1205 Make_Index_Or_Discriminant_Constraint (Loc,
1206 Constraints => New_List
1207 (New_Reference_To (Slice_Type, Loc)))));
1208
1209 -- This subtype indication may be used later for contraint checks
1210 -- we better make sure that if a variable was used as a bound of
1211 -- of the original slice, its value is frozen.
1212
1213 Force_Evaluation (Low_Bound (Scalar_Range (Slice_Type)));
1214 Force_Evaluation (High_Bound (Scalar_Range (Slice_Type)));
1215 end;
1216
1217 elsif Ekind (Exp_Typ) = E_String_Literal_Subtype then
1218 Rewrite (Subtype_Indic,
1219 Make_Subtype_Indication (Loc,
1220 Subtype_Mark => New_Reference_To (Unc_Type, Loc),
1221 Constraint =>
1222 Make_Index_Or_Discriminant_Constraint (Loc,
1223 Constraints => New_List (
1224 Make_Literal_Range (Loc,
1225 Literal_Typ => Exp_Typ)))));
1226
1227 elsif Is_Constrained (Exp_Typ)
1228 and then not Is_Class_Wide_Type (Unc_Type)
1229 then
1230 if Is_Itype (Exp_Typ) then
1231
1232 -- Within an initialization procedure, a selected component
1233 -- denotes a component of the enclosing record, and it appears
1234 -- as an actual in a call to its own initialization procedure.
1235 -- If this component depends on the outer discriminant, we must
1236 -- generate the proper actual subtype for it.
1237
1238 if Nkind (Exp) = N_Selected_Component
1239 and then Within_Init_Proc
1240 then
1241 declare
1242 Decl : constant Node_Id :=
1243 Build_Actual_Subtype_Of_Component (Exp_Typ, Exp);
1244 begin
1245 if Present (Decl) then
1246 Insert_Action (N, Decl);
1247 T := Defining_Identifier (Decl);
1248 else
1249 T := Exp_Typ;
1250 end if;
1251 end;
1252
1253 -- No need to generate a new one (new what???)
1254
1255 else
1256 T := Exp_Typ;
1257 end if;
1258
1259 else
1260 T :=
1261 Make_Defining_Identifier (Loc,
1262 Chars => New_Internal_Name ('T'));
1263
1264 Insert_Action (N,
1265 Make_Subtype_Declaration (Loc,
1266 Defining_Identifier => T,
1267 Subtype_Indication => New_Reference_To (Exp_Typ, Loc)));
1268
1269 -- This type is marked as an itype even though it has an
1270 -- explicit declaration because otherwise it can be marked
1271 -- with Is_Generic_Actual_Type and generate spurious errors.
1272 -- (see sem_ch8.Analyze_Package_Renaming and sem_type.covers)
1273
1274 Set_Is_Itype (T);
1275 Set_Associated_Node_For_Itype (T, Exp);
1276 end if;
1277
1278 Rewrite (Subtype_Indic, New_Reference_To (T, Loc));
1279
1280 -- nothing needs to be done for private types with unknown discriminants
1281 -- if the underlying type is not an unconstrained composite type.
1282
1283 elsif Is_Private_Type (Unc_Type)
1284 and then Has_Unknown_Discriminants (Unc_Type)
1285 and then (not Is_Composite_Type (Underlying_Type (Unc_Type))
1286 or else Is_Constrained (Underlying_Type (Unc_Type)))
1287 then
1288 null;
1289
1290 else
1291 Remove_Side_Effects (Exp);
1292 Rewrite (Subtype_Indic,
1293 Make_Subtype_From_Expr (Exp, Unc_Type));
1294 end if;
1295 end Expand_Subtype_From_Expr;
1296
1297 ------------------------
1298 -- Find_Interface_Tag --
1299 ------------------------
1300
1301 procedure Find_Interface_Tag
1302 (T : Entity_Id;
1303 Iface : Entity_Id;
1304 Iface_Tag : out Entity_Id;
1305 Iface_ADT : out Entity_Id)
1306 is
1307 AI_Tag : Entity_Id;
1308 ADT_Elmt : Elmt_Id;
1309 Found : Boolean := False;
1310
1311 procedure Find_AI_Tag (Typ : in Entity_Id; Found : in out Boolean);
1312 -- This must be commented ???
1313
1314 -----------------
1315 -- Find_AI_Tag --
1316 -----------------
1317
1318 procedure Find_AI_Tag (Typ : in Entity_Id; Found : in out Boolean) is
1319 T : Entity_Id := Typ;
1320 Etyp : Entity_Id; -- := Etype (Typ); -- why is this commented ???
1321 AI_Elmt : Elmt_Id;
1322 AI : Node_Id;
1323
1324 begin
1325 -- Check if the interface is an immediate ancestor of the type and
1326 -- therefore shares the main tag.
1327
1328 if Typ = Iface then
1329 AI_Tag := First_Tag_Component (Typ);
1330 ADT_Elmt := First_Elmt (Access_Disp_Table (Typ));
1331 Found := True;
1332 return;
1333 end if;
1334
1335 -- Handle private types
1336
1337 if Has_Private_Declaration (T)
1338 and then Present (Full_View (T))
1339 then
1340 T := Full_View (T);
1341 end if;
1342
1343 if Is_Access_Type (Typ) then
1344 T := Directly_Designated_Type (T);
1345
1346 elsif Ekind (T) = E_Protected_Type
1347 or else Ekind (T) = E_Task_Type
1348 then
1349 T := Corresponding_Record_Type (T);
1350 end if;
1351
1352 Etyp := Etype (T);
1353
1354 -- Climb to the root type
1355
1356 if Etyp /= Typ then
1357 Find_AI_Tag (Etyp, Found);
1358 end if;
1359
1360 -- Traverse the list of interfaces implemented by the type
1361
1362 if not Found
1363 and then Present (Abstract_Interfaces (T))
1364 and then not Is_Empty_Elmt_List (Abstract_Interfaces (T))
1365 then
1366 -- Skip the tag associated with the primary table (if
1367 -- already placed in the record)
1368
1369 if Etype (Node (First_Elmt
1370 (Access_Disp_Table (T)))) = RTE (RE_Tag)
1371 then
1372 AI_Tag := Next_Tag_Component (First_Tag_Component (T));
1373 ADT_Elmt := Next_Elmt (First_Elmt (Access_Disp_Table (T)));
1374 else
1375 AI_Tag := First_Tag_Component (T);
1376 ADT_Elmt := First_Elmt (Access_Disp_Table (T));
1377 end if;
1378
1379 pragma Assert (Present (AI_Tag));
1380 pragma Assert (Present (Node (ADT_Elmt)));
1381
1382 AI_Elmt := First_Elmt (Abstract_Interfaces (T));
1383 while Present (AI_Elmt) loop
1384 AI := Node (AI_Elmt);
1385
1386 if AI = Iface or else Is_Ancestor (Iface, AI) then
1387 Found := True;
1388 return;
1389 end if;
1390
1391 AI_Tag := Next_Tag_Component (AI_Tag);
1392 Next_Elmt (AI_Elmt);
1393 Next_Elmt (ADT_Elmt);
1394 end loop;
1395 end if;
1396 end Find_AI_Tag;
1397
1398 begin
1399 Find_AI_Tag (T, Found);
1400 pragma Assert (Found);
1401
1402 Iface_Tag := AI_Tag;
1403 Iface_ADT := Node (ADT_Elmt);
1404 end Find_Interface_Tag;
1405
1406 ------------------------
1407 -- Find_Interface_Tag --
1408 ------------------------
1409
1410 function Find_Interface_ADT
1411 (T : Entity_Id;
1412 Iface : Entity_Id) return Entity_Id
1413 is
1414 Iface_Tag : Entity_Id := Empty;
1415 Iface_ADT : Entity_Id := Empty;
1416 begin
1417 Find_Interface_Tag (T, Iface, Iface_Tag, Iface_ADT);
1418 return Iface_ADT;
1419 end Find_Interface_ADT;
1420
1421 ------------------------
1422 -- Find_Interface_Tag --
1423 ------------------------
1424
1425 function Find_Interface_Tag
1426 (T : Entity_Id;
1427 Iface : Entity_Id) return Entity_Id
1428 is
1429 Iface_Tag : Entity_Id := Empty;
1430 Iface_ADT : Entity_Id := Empty;
1431 begin
1432 Find_Interface_Tag (T, Iface, Iface_Tag, Iface_ADT);
1433 return Iface_Tag;
1434 end Find_Interface_Tag;
1435
1436 ------------------
1437 -- Find_Prim_Op --
1438 ------------------
1439
1440 function Find_Prim_Op (T : Entity_Id; Name : Name_Id) return Entity_Id is
1441 Prim : Elmt_Id;
1442 Typ : Entity_Id := T;
1443
1444 begin
1445 if Is_Class_Wide_Type (Typ) then
1446 Typ := Root_Type (Typ);
1447 end if;
1448
1449 Typ := Underlying_Type (Typ);
1450
1451 Prim := First_Elmt (Primitive_Operations (Typ));
1452 while Chars (Node (Prim)) /= Name loop
1453 Next_Elmt (Prim);
1454 pragma Assert (Present (Prim));
1455 end loop;
1456
1457 return Node (Prim);
1458 end Find_Prim_Op;
1459
1460 function Find_Prim_Op
1461 (T : Entity_Id;
1462 Name : TSS_Name_Type) return Entity_Id
1463 is
1464 Prim : Elmt_Id;
1465 Typ : Entity_Id := T;
1466
1467 begin
1468 if Is_Class_Wide_Type (Typ) then
1469 Typ := Root_Type (Typ);
1470 end if;
1471
1472 Typ := Underlying_Type (Typ);
1473
1474 Prim := First_Elmt (Primitive_Operations (Typ));
1475 while not Is_TSS (Node (Prim), Name) loop
1476 Next_Elmt (Prim);
1477 pragma Assert (Present (Prim));
1478 end loop;
1479
1480 return Node (Prim);
1481 end Find_Prim_Op;
1482
1483 ----------------------
1484 -- Force_Evaluation --
1485 ----------------------
1486
1487 procedure Force_Evaluation (Exp : Node_Id; Name_Req : Boolean := False) is
1488 Component_In_Lhs : Boolean := False;
1489 Par : Node_Id;
1490
1491 begin
1492 -- Loop to determine whether there is a component reference in the left
1493 -- hand side if Exp appears on the left side of an assignment statement.
1494 -- Needed to determine if form of result must be a variable.
1495
1496 Par := Exp;
1497 while Present (Par)
1498 and then
1499 (Nkind (Par) = N_Selected_Component
1500 or else
1501 Nkind (Par) = N_Indexed_Component)
1502 loop
1503 if Nkind (Parent (Par)) = N_Assignment_Statement
1504 and then Par = Name (Parent (Par))
1505 then
1506 Component_In_Lhs := True;
1507 exit;
1508 else
1509 Par := Parent (Par);
1510 end if;
1511 end loop;
1512
1513 -- If the expression is a selected component, it is being evaluated as
1514 -- part of a discriminant check. If it is part of a left-hand side, this
1515 -- is the last use of its value and it is safe to create a renaming for
1516 -- it, rather than a temporary. In addition, if it is not an addressable
1517 -- field, creating a temporary may be a problem for gigi, or might drop
1518 -- the value of the assignment. Therefore, if the expression is on the
1519 -- lhs of an assignment, remove side effects without requiring a
1520 -- temporary, and create a renaming. (See remove_side_effects for
1521 -- details).
1522
1523 Remove_Side_Effects
1524 (Exp, Name_Req, Variable_Ref => not Component_In_Lhs);
1525 end Force_Evaluation;
1526
1527 ------------------------
1528 -- Generate_Poll_Call --
1529 ------------------------
1530
1531 procedure Generate_Poll_Call (N : Node_Id) is
1532 begin
1533 -- No poll call if polling not active
1534
1535 if not Polling_Required then
1536 return;
1537
1538 -- Otherwise generate require poll call
1539
1540 else
1541 Insert_Before_And_Analyze (N,
1542 Make_Procedure_Call_Statement (Sloc (N),
1543 Name => New_Occurrence_Of (RTE (RE_Poll), Sloc (N))));
1544 end if;
1545 end Generate_Poll_Call;
1546
1547 ---------------------------------
1548 -- Get_Current_Value_Condition --
1549 ---------------------------------
1550
1551 procedure Get_Current_Value_Condition
1552 (Var : Node_Id;
1553 Op : out Node_Kind;
1554 Val : out Node_Id)
1555 is
1556 Loc : constant Source_Ptr := Sloc (Var);
1557 CV : constant Node_Id := Current_Value (Entity (Var));
1558 Sens : Boolean;
1559 Stm : Node_Id;
1560 Cond : Node_Id;
1561
1562 begin
1563 Op := N_Empty;
1564 Val := Empty;
1565
1566 -- If statement. Condition is known true in THEN section, known False
1567 -- in any ELSIF or ELSE part, and unknown outside the IF statement.
1568
1569 if Nkind (CV) = N_If_Statement then
1570
1571 -- Before start of IF statement
1572
1573 if Loc < Sloc (CV) then
1574 return;
1575
1576 -- After end of IF statement
1577
1578 elsif Loc >= Sloc (CV) + Text_Ptr (UI_To_Int (End_Span (CV))) then
1579 return;
1580 end if;
1581
1582 -- At this stage we know that we are within the IF statement, but
1583 -- unfortunately, the tree does not record the SLOC of the ELSE so
1584 -- we cannot use a simple SLOC comparison to distinguish between
1585 -- the then/else statements, so we have to climb the tree.
1586
1587 declare
1588 N : Node_Id;
1589
1590 begin
1591 N := Parent (Var);
1592 while Parent (N) /= CV loop
1593 N := Parent (N);
1594
1595 -- If we fall off the top of the tree, then that's odd, but
1596 -- perhaps it could occur in some error situation, and the
1597 -- safest response is simply to assume that the outcome of the
1598 -- condition is unknown. No point in bombing during an attempt
1599 -- to optimize things.
1600
1601 if No (N) then
1602 return;
1603 end if;
1604 end loop;
1605
1606 -- Now we have N pointing to a node whose parent is the IF
1607 -- statement in question, so now we can tell if we are within
1608 -- the THEN statements.
1609
1610 if Is_List_Member (N)
1611 and then List_Containing (N) = Then_Statements (CV)
1612 then
1613 Sens := True;
1614
1615 -- Otherwise we must be in ELSIF or ELSE part
1616
1617 else
1618 Sens := False;
1619 end if;
1620 end;
1621
1622 -- ELSIF part. Condition is known true within the referenced ELSIF,
1623 -- known False in any subsequent ELSIF or ELSE part, and unknown before
1624 -- the ELSE part or after the IF statement.
1625
1626 elsif Nkind (CV) = N_Elsif_Part then
1627 Stm := Parent (CV);
1628
1629 -- Before start of ELSIF part
1630
1631 if Loc < Sloc (CV) then
1632 return;
1633
1634 -- After end of IF statement
1635
1636 elsif Loc >= Sloc (Stm) +
1637 Text_Ptr (UI_To_Int (End_Span (Stm)))
1638 then
1639 return;
1640 end if;
1641
1642 -- Again we lack the SLOC of the ELSE, so we need to climb the tree
1643 -- to see if we are within the ELSIF part in question.
1644
1645 declare
1646 N : Node_Id;
1647
1648 begin
1649 N := Parent (Var);
1650 while Parent (N) /= Stm loop
1651 N := Parent (N);
1652
1653 -- If we fall off the top of the tree, then that's odd, but
1654 -- perhaps it could occur in some error situation, and the
1655 -- safest response is simply to assume that the outcome of the
1656 -- condition is unknown. No point in bombing during an attempt
1657 -- to optimize things.
1658
1659 if No (N) then
1660 return;
1661 end if;
1662 end loop;
1663
1664 -- Now we have N pointing to a node whose parent is the IF
1665 -- statement in question, so see if is the ELSIF part we want.
1666 -- the THEN statements.
1667
1668 if N = CV then
1669 Sens := True;
1670
1671 -- Otherwise we must be in susbequent ELSIF or ELSE part
1672
1673 else
1674 Sens := False;
1675 end if;
1676 end;
1677
1678 -- All other cases of Current_Value settings
1679
1680 else
1681 return;
1682 end if;
1683
1684 -- If we fall through here, then we have a reportable condition, Sens is
1685 -- True if the condition is true and False if it needs inverting.
1686
1687 -- Deal with NOT operators, inverting sense
1688
1689 Cond := Condition (CV);
1690 while Nkind (Cond) = N_Op_Not loop
1691 Cond := Right_Opnd (Cond);
1692 Sens := not Sens;
1693 end loop;
1694
1695 -- Now we must have a relational operator
1696
1697 pragma Assert (Entity (Var) = Entity (Left_Opnd (Cond)));
1698 Val := Right_Opnd (Cond);
1699 Op := Nkind (Cond);
1700
1701 if Sens = False then
1702 case Op is
1703 when N_Op_Eq => Op := N_Op_Ne;
1704 when N_Op_Ne => Op := N_Op_Eq;
1705 when N_Op_Lt => Op := N_Op_Ge;
1706 when N_Op_Gt => Op := N_Op_Le;
1707 when N_Op_Le => Op := N_Op_Gt;
1708 when N_Op_Ge => Op := N_Op_Lt;
1709
1710 -- No other entry should be possible
1711
1712 when others =>
1713 raise Program_Error;
1714 end case;
1715 end if;
1716 end Get_Current_Value_Condition;
1717
1718 --------------------
1719 -- Homonym_Number --
1720 --------------------
1721
1722 function Homonym_Number (Subp : Entity_Id) return Nat is
1723 Count : Nat;
1724 Hom : Entity_Id;
1725
1726 begin
1727 Count := 1;
1728 Hom := Homonym (Subp);
1729 while Present (Hom) loop
1730 if Scope (Hom) = Scope (Subp) then
1731 Count := Count + 1;
1732 end if;
1733
1734 Hom := Homonym (Hom);
1735 end loop;
1736
1737 return Count;
1738 end Homonym_Number;
1739
1740 ------------------------------
1741 -- In_Unconditional_Context --
1742 ------------------------------
1743
1744 function In_Unconditional_Context (Node : Node_Id) return Boolean is
1745 P : Node_Id;
1746
1747 begin
1748 P := Node;
1749 while Present (P) loop
1750 case Nkind (P) is
1751 when N_Subprogram_Body =>
1752 return True;
1753
1754 when N_If_Statement =>
1755 return False;
1756
1757 when N_Loop_Statement =>
1758 return False;
1759
1760 when N_Case_Statement =>
1761 return False;
1762
1763 when others =>
1764 P := Parent (P);
1765 end case;
1766 end loop;
1767
1768 return False;
1769 end In_Unconditional_Context;
1770
1771 -------------------
1772 -- Insert_Action --
1773 -------------------
1774
1775 procedure Insert_Action (Assoc_Node : Node_Id; Ins_Action : Node_Id) is
1776 begin
1777 if Present (Ins_Action) then
1778 Insert_Actions (Assoc_Node, New_List (Ins_Action));
1779 end if;
1780 end Insert_Action;
1781
1782 -- Version with check(s) suppressed
1783
1784 procedure Insert_Action
1785 (Assoc_Node : Node_Id; Ins_Action : Node_Id; Suppress : Check_Id)
1786 is
1787 begin
1788 Insert_Actions (Assoc_Node, New_List (Ins_Action), Suppress);
1789 end Insert_Action;
1790
1791 --------------------
1792 -- Insert_Actions --
1793 --------------------
1794
1795 procedure Insert_Actions (Assoc_Node : Node_Id; Ins_Actions : List_Id) is
1796 N : Node_Id;
1797 P : Node_Id;
1798
1799 Wrapped_Node : Node_Id := Empty;
1800
1801 begin
1802 if No (Ins_Actions) or else Is_Empty_List (Ins_Actions) then
1803 return;
1804 end if;
1805
1806 -- Ignore insert of actions from inside default expression in the
1807 -- special preliminary analyze mode. Any insertions at this point
1808 -- have no relevance, since we are only doing the analyze to freeze
1809 -- the types of any static expressions. See section "Handling of
1810 -- Default Expressions" in the spec of package Sem for further details.
1811
1812 if In_Default_Expression then
1813 return;
1814 end if;
1815
1816 -- If the action derives from stuff inside a record, then the actions
1817 -- are attached to the current scope, to be inserted and analyzed on
1818 -- exit from the scope. The reason for this is that we may also
1819 -- be generating freeze actions at the same time, and they must
1820 -- eventually be elaborated in the correct order.
1821
1822 if Is_Record_Type (Current_Scope)
1823 and then not Is_Frozen (Current_Scope)
1824 then
1825 if No (Scope_Stack.Table
1826 (Scope_Stack.Last).Pending_Freeze_Actions)
1827 then
1828 Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions :=
1829 Ins_Actions;
1830 else
1831 Append_List
1832 (Ins_Actions,
1833 Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions);
1834 end if;
1835
1836 return;
1837 end if;
1838
1839 -- We now intend to climb up the tree to find the right point to
1840 -- insert the actions. We start at Assoc_Node, unless this node is
1841 -- a subexpression in which case we start with its parent. We do this
1842 -- for two reasons. First it speeds things up. Second, if Assoc_Node
1843 -- is itself one of the special nodes like N_And_Then, then we assume
1844 -- that an initial request to insert actions for such a node does not
1845 -- expect the actions to get deposited in the node for later handling
1846 -- when the node is expanded, since clearly the node is being dealt
1847 -- with by the caller. Note that in the subexpression case, N is
1848 -- always the child we came from.
1849
1850 -- N_Raise_xxx_Error is an annoying special case, it is a statement
1851 -- if it has type Standard_Void_Type, and a subexpression otherwise.
1852 -- otherwise. Procedure attribute references are also statements.
1853
1854 if Nkind (Assoc_Node) in N_Subexpr
1855 and then (Nkind (Assoc_Node) in N_Raise_xxx_Error
1856 or else Etype (Assoc_Node) /= Standard_Void_Type)
1857 and then (Nkind (Assoc_Node) /= N_Attribute_Reference
1858 or else
1859 not Is_Procedure_Attribute_Name
1860 (Attribute_Name (Assoc_Node)))
1861 then
1862 P := Assoc_Node; -- ??? does not agree with above!
1863 N := Parent (Assoc_Node);
1864
1865 -- Non-subexpression case. Note that N is initially Empty in this
1866 -- case (N is only guaranteed Non-Empty in the subexpr case).
1867
1868 else
1869 P := Assoc_Node;
1870 N := Empty;
1871 end if;
1872
1873 -- Capture root of the transient scope
1874
1875 if Scope_Is_Transient then
1876 Wrapped_Node := Node_To_Be_Wrapped;
1877 end if;
1878
1879 loop
1880 pragma Assert (Present (P));
1881
1882 case Nkind (P) is
1883
1884 -- Case of right operand of AND THEN or OR ELSE. Put the actions
1885 -- in the Actions field of the right operand. They will be moved
1886 -- out further when the AND THEN or OR ELSE operator is expanded.
1887 -- Nothing special needs to be done for the left operand since
1888 -- in that case the actions are executed unconditionally.
1889
1890 when N_And_Then | N_Or_Else =>
1891 if N = Right_Opnd (P) then
1892 if Present (Actions (P)) then
1893 Insert_List_After_And_Analyze
1894 (Last (Actions (P)), Ins_Actions);
1895 else
1896 Set_Actions (P, Ins_Actions);
1897 Analyze_List (Actions (P));
1898 end if;
1899
1900 return;
1901 end if;
1902
1903 -- Then or Else operand of conditional expression. Add actions to
1904 -- Then_Actions or Else_Actions field as appropriate. The actions
1905 -- will be moved further out when the conditional is expanded.
1906
1907 when N_Conditional_Expression =>
1908 declare
1909 ThenX : constant Node_Id := Next (First (Expressions (P)));
1910 ElseX : constant Node_Id := Next (ThenX);
1911
1912 begin
1913 -- Actions belong to the then expression, temporarily
1914 -- place them as Then_Actions of the conditional expr.
1915 -- They will be moved to the proper place later when
1916 -- the conditional expression is expanded.
1917
1918 if N = ThenX then
1919 if Present (Then_Actions (P)) then
1920 Insert_List_After_And_Analyze
1921 (Last (Then_Actions (P)), Ins_Actions);
1922 else
1923 Set_Then_Actions (P, Ins_Actions);
1924 Analyze_List (Then_Actions (P));
1925 end if;
1926
1927 return;
1928
1929 -- Actions belong to the else expression, temporarily
1930 -- place them as Else_Actions of the conditional expr.
1931 -- They will be moved to the proper place later when
1932 -- the conditional expression is expanded.
1933
1934 elsif N = ElseX then
1935 if Present (Else_Actions (P)) then
1936 Insert_List_After_And_Analyze
1937 (Last (Else_Actions (P)), Ins_Actions);
1938 else
1939 Set_Else_Actions (P, Ins_Actions);
1940 Analyze_List (Else_Actions (P));
1941 end if;
1942
1943 return;
1944
1945 -- Actions belong to the condition. In this case they are
1946 -- unconditionally executed, and so we can continue the
1947 -- search for the proper insert point.
1948
1949 else
1950 null;
1951 end if;
1952 end;
1953
1954 -- Case of appearing in the condition of a while expression or
1955 -- elsif. We insert the actions into the Condition_Actions field.
1956 -- They will be moved further out when the while loop or elsif
1957 -- is analyzed.
1958
1959 when N_Iteration_Scheme |
1960 N_Elsif_Part
1961 =>
1962 if N = Condition (P) then
1963 if Present (Condition_Actions (P)) then
1964 Insert_List_After_And_Analyze
1965 (Last (Condition_Actions (P)), Ins_Actions);
1966 else
1967 Set_Condition_Actions (P, Ins_Actions);
1968
1969 -- Set the parent of the insert actions explicitly.
1970 -- This is not a syntactic field, but we need the
1971 -- parent field set, in particular so that freeze
1972 -- can understand that it is dealing with condition
1973 -- actions, and properly insert the freezing actions.
1974
1975 Set_Parent (Ins_Actions, P);
1976 Analyze_List (Condition_Actions (P));
1977 end if;
1978
1979 return;
1980 end if;
1981
1982 -- Statements, declarations, pragmas, representation clauses
1983
1984 when
1985 -- Statements
1986
1987 N_Procedure_Call_Statement |
1988 N_Statement_Other_Than_Procedure_Call |
1989
1990 -- Pragmas
1991
1992 N_Pragma |
1993
1994 -- Representation_Clause
1995
1996 N_At_Clause |
1997 N_Attribute_Definition_Clause |
1998 N_Enumeration_Representation_Clause |
1999 N_Record_Representation_Clause |
2000
2001 -- Declarations
2002
2003 N_Abstract_Subprogram_Declaration |
2004 N_Entry_Body |
2005 N_Exception_Declaration |
2006 N_Exception_Renaming_Declaration |
2007 N_Formal_Abstract_Subprogram_Declaration |
2008 N_Formal_Concrete_Subprogram_Declaration |
2009 N_Formal_Object_Declaration |
2010 N_Formal_Type_Declaration |
2011 N_Full_Type_Declaration |
2012 N_Function_Instantiation |
2013 N_Generic_Function_Renaming_Declaration |
2014 N_Generic_Package_Declaration |
2015 N_Generic_Package_Renaming_Declaration |
2016 N_Generic_Procedure_Renaming_Declaration |
2017 N_Generic_Subprogram_Declaration |
2018 N_Implicit_Label_Declaration |
2019 N_Incomplete_Type_Declaration |
2020 N_Number_Declaration |
2021 N_Object_Declaration |
2022 N_Object_Renaming_Declaration |
2023 N_Package_Body |
2024 N_Package_Body_Stub |
2025 N_Package_Declaration |
2026 N_Package_Instantiation |
2027 N_Package_Renaming_Declaration |
2028 N_Private_Extension_Declaration |
2029 N_Private_Type_Declaration |
2030 N_Procedure_Instantiation |
2031 N_Protected_Body_Stub |
2032 N_Protected_Type_Declaration |
2033 N_Single_Task_Declaration |
2034 N_Subprogram_Body |
2035 N_Subprogram_Body_Stub |
2036 N_Subprogram_Declaration |
2037 N_Subprogram_Renaming_Declaration |
2038 N_Subtype_Declaration |
2039 N_Task_Body |
2040 N_Task_Body_Stub |
2041 N_Task_Type_Declaration |
2042
2043 -- Freeze entity behaves like a declaration or statement
2044
2045 N_Freeze_Entity
2046 =>
2047 -- Do not insert here if the item is not a list member (this
2048 -- happens for example with a triggering statement, and the
2049 -- proper approach is to insert before the entire select).
2050
2051 if not Is_List_Member (P) then
2052 null;
2053
2054 -- Do not insert if parent of P is an N_Component_Association
2055 -- node (i.e. we are in the context of an N_Aggregate node.
2056 -- In this case we want to insert before the entire aggregate.
2057
2058 elsif Nkind (Parent (P)) = N_Component_Association then
2059 null;
2060
2061 -- Do not insert if the parent of P is either an N_Variant
2062 -- node or an N_Record_Definition node, meaning in either
2063 -- case that P is a member of a component list, and that
2064 -- therefore the actions should be inserted outside the
2065 -- complete record declaration.
2066
2067 elsif Nkind (Parent (P)) = N_Variant
2068 or else Nkind (Parent (P)) = N_Record_Definition
2069 then
2070 null;
2071
2072 -- Do not insert freeze nodes within the loop generated for
2073 -- an aggregate, because they may be elaborated too late for
2074 -- subsequent use in the back end: within a package spec the
2075 -- loop is part of the elaboration procedure and is only
2076 -- elaborated during the second pass.
2077 -- If the loop comes from source, or the entity is local to
2078 -- the loop itself it must remain within.
2079
2080 elsif Nkind (Parent (P)) = N_Loop_Statement
2081 and then not Comes_From_Source (Parent (P))
2082 and then Nkind (First (Ins_Actions)) = N_Freeze_Entity
2083 and then
2084 Scope (Entity (First (Ins_Actions))) /= Current_Scope
2085 then
2086 null;
2087
2088 -- Otherwise we can go ahead and do the insertion
2089
2090 elsif P = Wrapped_Node then
2091 Store_Before_Actions_In_Scope (Ins_Actions);
2092 return;
2093
2094 else
2095 Insert_List_Before_And_Analyze (P, Ins_Actions);
2096 return;
2097 end if;
2098
2099 -- A special case, N_Raise_xxx_Error can act either as a
2100 -- statement or a subexpression. We tell the difference
2101 -- by looking at the Etype. It is set to Standard_Void_Type
2102 -- in the statement case.
2103
2104 when
2105 N_Raise_xxx_Error =>
2106 if Etype (P) = Standard_Void_Type then
2107 if P = Wrapped_Node then
2108 Store_Before_Actions_In_Scope (Ins_Actions);
2109 else
2110 Insert_List_Before_And_Analyze (P, Ins_Actions);
2111 end if;
2112
2113 return;
2114
2115 -- In the subexpression case, keep climbing
2116
2117 else
2118 null;
2119 end if;
2120
2121 -- If a component association appears within a loop created for
2122 -- an array aggregate, attach the actions to the association so
2123 -- they can be subsequently inserted within the loop. For other
2124 -- component associations insert outside of the aggregate. For
2125 -- an association that will generate a loop, its Loop_Actions
2126 -- attribute is already initialized (see exp_aggr.adb).
2127
2128 -- The list of loop_actions can in turn generate additional ones,
2129 -- that are inserted before the associated node. If the associated
2130 -- node is outside the aggregate, the new actions are collected
2131 -- at the end of the loop actions, to respect the order in which
2132 -- they are to be elaborated.
2133
2134 when
2135 N_Component_Association =>
2136 if Nkind (Parent (P)) = N_Aggregate
2137 and then Present (Loop_Actions (P))
2138 then
2139 if Is_Empty_List (Loop_Actions (P)) then
2140 Set_Loop_Actions (P, Ins_Actions);
2141 Analyze_List (Ins_Actions);
2142
2143 else
2144 declare
2145 Decl : Node_Id;
2146
2147 begin
2148 -- Check whether these actions were generated
2149 -- by a declaration that is part of the loop_
2150 -- actions for the component_association.
2151
2152 Decl := Assoc_Node;
2153 while Present (Decl) loop
2154 exit when Parent (Decl) = P
2155 and then Is_List_Member (Decl)
2156 and then
2157 List_Containing (Decl) = Loop_Actions (P);
2158 Decl := Parent (Decl);
2159 end loop;
2160
2161 if Present (Decl) then
2162 Insert_List_Before_And_Analyze
2163 (Decl, Ins_Actions);
2164 else
2165 Insert_List_After_And_Analyze
2166 (Last (Loop_Actions (P)), Ins_Actions);
2167 end if;
2168 end;
2169 end if;
2170
2171 return;
2172
2173 else
2174 null;
2175 end if;
2176
2177 -- Another special case, an attribute denoting a procedure call
2178
2179 when
2180 N_Attribute_Reference =>
2181 if Is_Procedure_Attribute_Name (Attribute_Name (P)) then
2182 if P = Wrapped_Node then
2183 Store_Before_Actions_In_Scope (Ins_Actions);
2184 else
2185 Insert_List_Before_And_Analyze (P, Ins_Actions);
2186 end if;
2187
2188 return;
2189
2190 -- In the subexpression case, keep climbing
2191
2192 else
2193 null;
2194 end if;
2195
2196 -- For all other node types, keep climbing tree
2197
2198 when
2199 N_Abortable_Part |
2200 N_Accept_Alternative |
2201 N_Access_Definition |
2202 N_Access_Function_Definition |
2203 N_Access_Procedure_Definition |
2204 N_Access_To_Object_Definition |
2205 N_Aggregate |
2206 N_Allocator |
2207 N_Case_Statement_Alternative |
2208 N_Character_Literal |
2209 N_Compilation_Unit |
2210 N_Compilation_Unit_Aux |
2211 N_Component_Clause |
2212 N_Component_Declaration |
2213 N_Component_Definition |
2214 N_Component_List |
2215 N_Constrained_Array_Definition |
2216 N_Decimal_Fixed_Point_Definition |
2217 N_Defining_Character_Literal |
2218 N_Defining_Identifier |
2219 N_Defining_Operator_Symbol |
2220 N_Defining_Program_Unit_Name |
2221 N_Delay_Alternative |
2222 N_Delta_Constraint |
2223 N_Derived_Type_Definition |
2224 N_Designator |
2225 N_Digits_Constraint |
2226 N_Discriminant_Association |
2227 N_Discriminant_Specification |
2228 N_Empty |
2229 N_Entry_Body_Formal_Part |
2230 N_Entry_Call_Alternative |
2231 N_Entry_Declaration |
2232 N_Entry_Index_Specification |
2233 N_Enumeration_Type_Definition |
2234 N_Error |
2235 N_Exception_Handler |
2236 N_Expanded_Name |
2237 N_Explicit_Dereference |
2238 N_Extension_Aggregate |
2239 N_Floating_Point_Definition |
2240 N_Formal_Decimal_Fixed_Point_Definition |
2241 N_Formal_Derived_Type_Definition |
2242 N_Formal_Discrete_Type_Definition |
2243 N_Formal_Floating_Point_Definition |
2244 N_Formal_Modular_Type_Definition |
2245 N_Formal_Ordinary_Fixed_Point_Definition |
2246 N_Formal_Package_Declaration |
2247 N_Formal_Private_Type_Definition |
2248 N_Formal_Signed_Integer_Type_Definition |
2249 N_Function_Call |
2250 N_Function_Specification |
2251 N_Generic_Association |
2252 N_Handled_Sequence_Of_Statements |
2253 N_Identifier |
2254 N_In |
2255 N_Index_Or_Discriminant_Constraint |
2256 N_Indexed_Component |
2257 N_Integer_Literal |
2258 N_Itype_Reference |
2259 N_Label |
2260 N_Loop_Parameter_Specification |
2261 N_Mod_Clause |
2262 N_Modular_Type_Definition |
2263 N_Not_In |
2264 N_Null |
2265 N_Op_Abs |
2266 N_Op_Add |
2267 N_Op_And |
2268 N_Op_Concat |
2269 N_Op_Divide |
2270 N_Op_Eq |
2271 N_Op_Expon |
2272 N_Op_Ge |
2273 N_Op_Gt |
2274 N_Op_Le |
2275 N_Op_Lt |
2276 N_Op_Minus |
2277 N_Op_Mod |
2278 N_Op_Multiply |
2279 N_Op_Ne |
2280 N_Op_Not |
2281 N_Op_Or |
2282 N_Op_Plus |
2283 N_Op_Rem |
2284 N_Op_Rotate_Left |
2285 N_Op_Rotate_Right |
2286 N_Op_Shift_Left |
2287 N_Op_Shift_Right |
2288 N_Op_Shift_Right_Arithmetic |
2289 N_Op_Subtract |
2290 N_Op_Xor |
2291 N_Operator_Symbol |
2292 N_Ordinary_Fixed_Point_Definition |
2293 N_Others_Choice |
2294 N_Package_Specification |
2295 N_Parameter_Association |
2296 N_Parameter_Specification |
2297 N_Pragma_Argument_Association |
2298 N_Procedure_Specification |
2299 N_Protected_Body |
2300 N_Protected_Definition |
2301 N_Qualified_Expression |
2302 N_Range |
2303 N_Range_Constraint |
2304 N_Real_Literal |
2305 N_Real_Range_Specification |
2306 N_Record_Definition |
2307 N_Reference |
2308 N_Selected_Component |
2309 N_Signed_Integer_Type_Definition |
2310 N_Single_Protected_Declaration |
2311 N_Slice |
2312 N_String_Literal |
2313 N_Subprogram_Info |
2314 N_Subtype_Indication |
2315 N_Subunit |
2316 N_Task_Definition |
2317 N_Terminate_Alternative |
2318 N_Triggering_Alternative |
2319 N_Type_Conversion |
2320 N_Unchecked_Expression |
2321 N_Unchecked_Type_Conversion |
2322 N_Unconstrained_Array_Definition |
2323 N_Unused_At_End |
2324 N_Unused_At_Start |
2325 N_Use_Package_Clause |
2326 N_Use_Type_Clause |
2327 N_Variant |
2328 N_Variant_Part |
2329 N_Validate_Unchecked_Conversion |
2330 N_With_Clause |
2331 N_With_Type_Clause
2332 =>
2333 null;
2334
2335 end case;
2336
2337 -- Make sure that inserted actions stay in the transient scope
2338
2339 if P = Wrapped_Node then
2340 Store_Before_Actions_In_Scope (Ins_Actions);
2341 return;
2342 end if;
2343
2344 -- If we fall through above tests, keep climbing tree
2345
2346 N := P;
2347
2348 if Nkind (Parent (N)) = N_Subunit then
2349
2350 -- This is the proper body corresponding to a stub. Insertion
2351 -- must be done at the point of the stub, which is in the decla-
2352 -- tive part of the parent unit.
2353
2354 P := Corresponding_Stub (Parent (N));
2355
2356 else
2357 P := Parent (N);
2358 end if;
2359 end loop;
2360
2361 end Insert_Actions;
2362
2363 -- Version with check(s) suppressed
2364
2365 procedure Insert_Actions
2366 (Assoc_Node : Node_Id; Ins_Actions : List_Id; Suppress : Check_Id)
2367 is
2368 begin
2369 if Suppress = All_Checks then
2370 declare
2371 Svg : constant Suppress_Array := Scope_Suppress;
2372
2373 begin
2374 Scope_Suppress := (others => True);
2375 Insert_Actions (Assoc_Node, Ins_Actions);
2376 Scope_Suppress := Svg;
2377 end;
2378
2379 else
2380 declare
2381 Svg : constant Boolean := Scope_Suppress (Suppress);
2382
2383 begin
2384 Scope_Suppress (Suppress) := True;
2385 Insert_Actions (Assoc_Node, Ins_Actions);
2386 Scope_Suppress (Suppress) := Svg;
2387 end;
2388 end if;
2389 end Insert_Actions;
2390
2391 --------------------------
2392 -- Insert_Actions_After --
2393 --------------------------
2394
2395 procedure Insert_Actions_After
2396 (Assoc_Node : Node_Id;
2397 Ins_Actions : List_Id)
2398 is
2399 begin
2400 if Scope_Is_Transient
2401 and then Assoc_Node = Node_To_Be_Wrapped
2402 then
2403 Store_After_Actions_In_Scope (Ins_Actions);
2404 else
2405 Insert_List_After_And_Analyze (Assoc_Node, Ins_Actions);
2406 end if;
2407 end Insert_Actions_After;
2408
2409 ---------------------------------
2410 -- Insert_Library_Level_Action --
2411 ---------------------------------
2412
2413 procedure Insert_Library_Level_Action (N : Node_Id) is
2414 Aux : constant Node_Id := Aux_Decls_Node (Cunit (Main_Unit));
2415
2416 begin
2417 New_Scope (Cunit_Entity (Main_Unit));
2418
2419 if No (Actions (Aux)) then
2420 Set_Actions (Aux, New_List (N));
2421 else
2422 Append (N, Actions (Aux));
2423 end if;
2424
2425 Analyze (N);
2426 Pop_Scope;
2427 end Insert_Library_Level_Action;
2428
2429 ----------------------------------
2430 -- Insert_Library_Level_Actions --
2431 ----------------------------------
2432
2433 procedure Insert_Library_Level_Actions (L : List_Id) is
2434 Aux : constant Node_Id := Aux_Decls_Node (Cunit (Main_Unit));
2435
2436 begin
2437 if Is_Non_Empty_List (L) then
2438 New_Scope (Cunit_Entity (Main_Unit));
2439
2440 if No (Actions (Aux)) then
2441 Set_Actions (Aux, L);
2442 Analyze_List (L);
2443 else
2444 Insert_List_After_And_Analyze (Last (Actions (Aux)), L);
2445 end if;
2446
2447 Pop_Scope;
2448 end if;
2449 end Insert_Library_Level_Actions;
2450
2451 ----------------------
2452 -- Inside_Init_Proc --
2453 ----------------------
2454
2455 function Inside_Init_Proc return Boolean is
2456 S : Entity_Id;
2457
2458 begin
2459 S := Current_Scope;
2460 while Present (S)
2461 and then S /= Standard_Standard
2462 loop
2463 if Is_Init_Proc (S) then
2464 return True;
2465 else
2466 S := Scope (S);
2467 end if;
2468 end loop;
2469
2470 return False;
2471 end Inside_Init_Proc;
2472
2473 ----------------------------
2474 -- Is_All_Null_Statements --
2475 ----------------------------
2476
2477 function Is_All_Null_Statements (L : List_Id) return Boolean is
2478 Stm : Node_Id;
2479
2480 begin
2481 Stm := First (L);
2482 while Present (Stm) loop
2483 if Nkind (Stm) /= N_Null_Statement then
2484 return False;
2485 end if;
2486
2487 Next (Stm);
2488 end loop;
2489
2490 return True;
2491 end Is_All_Null_Statements;
2492
2493 ------------------------
2494 -- Is_Default_Prim_Op --
2495 ------------------------
2496
2497 function Is_Predefined_Dispatching_Operation
2498 (Subp : Entity_Id) return Boolean
2499 is
2500 TSS_Name : TSS_Name_Type;
2501 E : Entity_Id := Subp;
2502 begin
2503 pragma Assert (Is_Dispatching_Operation (Subp));
2504
2505 -- Handle overriden subprograms
2506
2507 while Present (Alias (E)) loop
2508 E := Alias (E);
2509 end loop;
2510
2511 Get_Name_String (Chars (E));
2512
2513 if Name_Len > TSS_Name_Type'Last then
2514 TSS_Name := TSS_Name_Type (Name_Buffer (Name_Len - TSS_Name'Length + 1
2515 .. Name_Len));
2516 if Chars (E) = Name_uSize
2517 or else Chars (E) = Name_uAlignment
2518 or else TSS_Name = TSS_Stream_Read
2519 or else TSS_Name = TSS_Stream_Write
2520 or else TSS_Name = TSS_Stream_Input
2521 or else TSS_Name = TSS_Stream_Output
2522 or else Chars (E) = Name_Op_Eq
2523 or else Chars (E) = Name_uAssign
2524 or else TSS_Name = TSS_Deep_Adjust
2525 or else TSS_Name = TSS_Deep_Finalize
2526 then
2527 return True;
2528 end if;
2529 end if;
2530
2531 return False;
2532 end Is_Predefined_Dispatching_Operation;
2533
2534 ----------------------------------
2535 -- Is_Possibly_Unaligned_Object --
2536 ----------------------------------
2537
2538 function Is_Possibly_Unaligned_Object (N : Node_Id) return Boolean is
2539 T : constant Entity_Id := Etype (N);
2540
2541 begin
2542 -- If renamed object, apply test to underlying object
2543
2544 if Is_Entity_Name (N)
2545 and then Is_Object (Entity (N))
2546 and then Present (Renamed_Object (Entity (N)))
2547 then
2548 return Is_Possibly_Unaligned_Object (Renamed_Object (Entity (N)));
2549 end if;
2550
2551 -- Tagged and controlled types and aliased types are always aligned,
2552 -- as are concurrent types.
2553
2554 if Is_Aliased (T)
2555 or else Has_Controlled_Component (T)
2556 or else Is_Concurrent_Type (T)
2557 or else Is_Tagged_Type (T)
2558 or else Is_Controlled (T)
2559 then
2560 return False;
2561 end if;
2562
2563 -- If this is an element of a packed array, may be unaligned
2564
2565 if Is_Ref_To_Bit_Packed_Array (N) then
2566 return True;
2567 end if;
2568
2569 -- Case of component reference
2570
2571 if Nkind (N) = N_Selected_Component then
2572 declare
2573 P : constant Node_Id := Prefix (N);
2574 C : constant Entity_Id := Entity (Selector_Name (N));
2575 M : Nat;
2576 S : Nat;
2577
2578 begin
2579 -- If component reference is for an array with non-static bounds,
2580 -- then it is always aligned: we can only process unaligned
2581 -- arrays with static bounds (more accurately bounds known at
2582 -- compile time).
2583
2584 if Is_Array_Type (T)
2585 and then not Compile_Time_Known_Bounds (T)
2586 then
2587 return False;
2588 end if;
2589
2590 -- If component is aliased, it is definitely properly aligned
2591
2592 if Is_Aliased (C) then
2593 return False;
2594 end if;
2595
2596 -- If component is for a type implemented as a scalar, and the
2597 -- record is packed, and the component is other than the first
2598 -- component of the record, then the component may be unaligned.
2599
2600 if Is_Packed (Etype (P))
2601 and then Represented_As_Scalar (Etype (C))
2602 and then First_Entity (Scope (C)) /= C
2603 then
2604 return True;
2605 end if;
2606
2607 -- Compute maximum possible alignment for T
2608
2609 -- If alignment is known, then that settles things
2610
2611 if Known_Alignment (T) then
2612 M := UI_To_Int (Alignment (T));
2613
2614 -- If alignment is not known, tentatively set max alignment
2615
2616 else
2617 M := Ttypes.Maximum_Alignment;
2618
2619 -- We can reduce this if the Esize is known since the default
2620 -- alignment will never be more than the smallest power of 2
2621 -- that does not exceed this Esize value.
2622
2623 if Known_Esize (T) then
2624 S := UI_To_Int (Esize (T));
2625
2626 while (M / 2) >= S loop
2627 M := M / 2;
2628 end loop;
2629 end if;
2630 end if;
2631
2632 -- If the component reference is for a record that has a specified
2633 -- alignment, and we either know it is too small, or cannot tell,
2634 -- then the component may be unaligned
2635
2636 if Known_Alignment (Etype (P))
2637 and then Alignment (Etype (P)) < Ttypes.Maximum_Alignment
2638 and then M > Alignment (Etype (P))
2639 then
2640 return True;
2641 end if;
2642
2643 -- Case of component clause present which may specify an
2644 -- unaligned position.
2645
2646 if Present (Component_Clause (C)) then
2647
2648 -- Otherwise we can do a test to make sure that the actual
2649 -- start position in the record, and the length, are both
2650 -- consistent with the required alignment. If not, we know
2651 -- that we are unaligned.
2652
2653 declare
2654 Align_In_Bits : constant Nat := M * System_Storage_Unit;
2655 begin
2656 if Component_Bit_Offset (C) mod Align_In_Bits /= 0
2657 or else Esize (C) mod Align_In_Bits /= 0
2658 then
2659 return True;
2660 end if;
2661 end;
2662 end if;
2663
2664 -- Otherwise, for a component reference, test prefix
2665
2666 return Is_Possibly_Unaligned_Object (P);
2667 end;
2668
2669 -- If not a component reference, must be aligned
2670
2671 else
2672 return False;
2673 end if;
2674 end Is_Possibly_Unaligned_Object;
2675
2676 ---------------------------------
2677 -- Is_Possibly_Unaligned_Slice --
2678 ---------------------------------
2679
2680 function Is_Possibly_Unaligned_Slice (N : Node_Id) return Boolean is
2681 begin
2682 -- ??? GCC3 will eventually handle strings with arbitrary alignments,
2683 -- but for now the following check must be disabled.
2684
2685 -- if get_gcc_version >= 3 then
2686 -- return False;
2687 -- end if;
2688
2689 -- For renaming case, go to renamed object
2690
2691 if Is_Entity_Name (N)
2692 and then Is_Object (Entity (N))
2693 and then Present (Renamed_Object (Entity (N)))
2694 then
2695 return Is_Possibly_Unaligned_Slice (Renamed_Object (Entity (N)));
2696 end if;
2697
2698 -- The reference must be a slice
2699
2700 if Nkind (N) /= N_Slice then
2701 return False;
2702 end if;
2703
2704 -- Always assume the worst for a nested record component with a
2705 -- component clause, which gigi/gcc does not appear to handle well.
2706 -- It is not clear why this special test is needed at all ???
2707
2708 if Nkind (Prefix (N)) = N_Selected_Component
2709 and then Nkind (Prefix (Prefix (N))) = N_Selected_Component
2710 and then
2711 Present (Component_Clause (Entity (Selector_Name (Prefix (N)))))
2712 then
2713 return True;
2714 end if;
2715
2716 -- We only need to worry if the target has strict alignment
2717
2718 if not Target_Strict_Alignment then
2719 return False;
2720 end if;
2721
2722 -- If it is a slice, then look at the array type being sliced
2723
2724 declare
2725 Sarr : constant Node_Id := Prefix (N);
2726 -- Prefix of the slice, i.e. the array being sliced
2727
2728 Styp : constant Entity_Id := Etype (Prefix (N));
2729 -- Type of the array being sliced
2730
2731 Pref : Node_Id;
2732 Ptyp : Entity_Id;
2733
2734 begin
2735 -- The problems arise if the array object that is being sliced
2736 -- is a component of a record or array, and we cannot guarantee
2737 -- the alignment of the array within its containing object.
2738
2739 -- To investigate this, we look at successive prefixes to see
2740 -- if we have a worrisome indexed or selected component.
2741
2742 Pref := Sarr;
2743 loop
2744 -- Case of array is part of an indexed component reference
2745
2746 if Nkind (Pref) = N_Indexed_Component then
2747 Ptyp := Etype (Prefix (Pref));
2748
2749 -- The only problematic case is when the array is packed,
2750 -- in which case we really know nothing about the alignment
2751 -- of individual components.
2752
2753 if Is_Bit_Packed_Array (Ptyp) then
2754 return True;
2755 end if;
2756
2757 -- Case of array is part of a selected component reference
2758
2759 elsif Nkind (Pref) = N_Selected_Component then
2760 Ptyp := Etype (Prefix (Pref));
2761
2762 -- We are definitely in trouble if the record in question
2763 -- has an alignment, and either we know this alignment is
2764 -- inconsistent with the alignment of the slice, or we
2765 -- don't know what the alignment of the slice should be.
2766
2767 if Known_Alignment (Ptyp)
2768 and then (Unknown_Alignment (Styp)
2769 or else Alignment (Styp) > Alignment (Ptyp))
2770 then
2771 return True;
2772 end if;
2773
2774 -- We are in potential trouble if the record type is packed.
2775 -- We could special case when we know that the array is the
2776 -- first component, but that's not such a simple case ???
2777
2778 if Is_Packed (Ptyp) then
2779 return True;
2780 end if;
2781
2782 -- We are in trouble if there is a component clause, and
2783 -- either we do not know the alignment of the slice, or
2784 -- the alignment of the slice is inconsistent with the
2785 -- bit position specified by the component clause.
2786
2787 declare
2788 Field : constant Entity_Id := Entity (Selector_Name (Pref));
2789 begin
2790 if Present (Component_Clause (Field))
2791 and then
2792 (Unknown_Alignment (Styp)
2793 or else
2794 (Component_Bit_Offset (Field) mod
2795 (System_Storage_Unit * Alignment (Styp))) /= 0)
2796 then
2797 return True;
2798 end if;
2799 end;
2800
2801 -- For cases other than selected or indexed components we
2802 -- know we are OK, since no issues arise over alignment.
2803
2804 else
2805 return False;
2806 end if;
2807
2808 -- We processed an indexed component or selected component
2809 -- reference that looked safe, so keep checking prefixes.
2810
2811 Pref := Prefix (Pref);
2812 end loop;
2813 end;
2814 end Is_Possibly_Unaligned_Slice;
2815
2816 --------------------------------
2817 -- Is_Ref_To_Bit_Packed_Array --
2818 --------------------------------
2819
2820 function Is_Ref_To_Bit_Packed_Array (N : Node_Id) return Boolean is
2821 Result : Boolean;
2822 Expr : Node_Id;
2823
2824 begin
2825 if Is_Entity_Name (N)
2826 and then Is_Object (Entity (N))
2827 and then Present (Renamed_Object (Entity (N)))
2828 then
2829 return Is_Ref_To_Bit_Packed_Array (Renamed_Object (Entity (N)));
2830 end if;
2831
2832 if Nkind (N) = N_Indexed_Component
2833 or else
2834 Nkind (N) = N_Selected_Component
2835 then
2836 if Is_Bit_Packed_Array (Etype (Prefix (N))) then
2837 Result := True;
2838 else
2839 Result := Is_Ref_To_Bit_Packed_Array (Prefix (N));
2840 end if;
2841
2842 if Result and then Nkind (N) = N_Indexed_Component then
2843 Expr := First (Expressions (N));
2844 while Present (Expr) loop
2845 Force_Evaluation (Expr);
2846 Next (Expr);
2847 end loop;
2848 end if;
2849
2850 return Result;
2851
2852 else
2853 return False;
2854 end if;
2855 end Is_Ref_To_Bit_Packed_Array;
2856
2857 --------------------------------
2858 -- Is_Ref_To_Bit_Packed_Slice --
2859 --------------------------------
2860
2861 function Is_Ref_To_Bit_Packed_Slice (N : Node_Id) return Boolean is
2862 begin
2863 if Is_Entity_Name (N)
2864 and then Is_Object (Entity (N))
2865 and then Present (Renamed_Object (Entity (N)))
2866 then
2867 return Is_Ref_To_Bit_Packed_Slice (Renamed_Object (Entity (N)));
2868 end if;
2869
2870 if Nkind (N) = N_Slice
2871 and then Is_Bit_Packed_Array (Etype (Prefix (N)))
2872 then
2873 return True;
2874
2875 elsif Nkind (N) = N_Indexed_Component
2876 or else
2877 Nkind (N) = N_Selected_Component
2878 then
2879 return Is_Ref_To_Bit_Packed_Slice (Prefix (N));
2880
2881 else
2882 return False;
2883 end if;
2884 end Is_Ref_To_Bit_Packed_Slice;
2885
2886 -----------------------
2887 -- Is_Renamed_Object --
2888 -----------------------
2889
2890 function Is_Renamed_Object (N : Node_Id) return Boolean is
2891 Pnod : constant Node_Id := Parent (N);
2892 Kind : constant Node_Kind := Nkind (Pnod);
2893
2894 begin
2895 if Kind = N_Object_Renaming_Declaration then
2896 return True;
2897
2898 elsif Kind = N_Indexed_Component
2899 or else Kind = N_Selected_Component
2900 then
2901 return Is_Renamed_Object (Pnod);
2902
2903 else
2904 return False;
2905 end if;
2906 end Is_Renamed_Object;
2907
2908 ----------------------------
2909 -- Is_Untagged_Derivation --
2910 ----------------------------
2911
2912 function Is_Untagged_Derivation (T : Entity_Id) return Boolean is
2913 begin
2914 return (not Is_Tagged_Type (T) and then Is_Derived_Type (T))
2915 or else
2916 (Is_Private_Type (T) and then Present (Full_View (T))
2917 and then not Is_Tagged_Type (Full_View (T))
2918 and then Is_Derived_Type (Full_View (T))
2919 and then Etype (Full_View (T)) /= T);
2920
2921 end Is_Untagged_Derivation;
2922
2923 --------------------
2924 -- Kill_Dead_Code --
2925 --------------------
2926
2927 procedure Kill_Dead_Code (N : Node_Id) is
2928 begin
2929 if Present (N) then
2930 Remove_Handler_Entries (N);
2931 Remove_Warning_Messages (N);
2932
2933 -- Recurse into block statements and bodies to process declarations
2934 -- and statements
2935
2936 if Nkind (N) = N_Block_Statement
2937 or else Nkind (N) = N_Subprogram_Body
2938 or else Nkind (N) = N_Package_Body
2939 then
2940 Kill_Dead_Code (Declarations (N));
2941 Kill_Dead_Code (Statements (Handled_Statement_Sequence (N)));
2942
2943 if Nkind (N) = N_Subprogram_Body then
2944 Set_Is_Eliminated (Defining_Entity (N));
2945 end if;
2946
2947 elsif Nkind (N) = N_Package_Declaration then
2948 Kill_Dead_Code (Visible_Declarations (Specification (N)));
2949 Kill_Dead_Code (Private_Declarations (Specification (N)));
2950
2951 declare
2952 E : Entity_Id := First_Entity (Defining_Entity (N));
2953 begin
2954 while Present (E) loop
2955 if Ekind (E) = E_Operator then
2956 Set_Is_Eliminated (E);
2957 end if;
2958
2959 Next_Entity (E);
2960 end loop;
2961 end;
2962
2963 -- Recurse into composite statement to kill individual statements,
2964 -- in particular instantiations.
2965
2966 elsif Nkind (N) = N_If_Statement then
2967 Kill_Dead_Code (Then_Statements (N));
2968 Kill_Dead_Code (Elsif_Parts (N));
2969 Kill_Dead_Code (Else_Statements (N));
2970
2971 elsif Nkind (N) = N_Loop_Statement then
2972 Kill_Dead_Code (Statements (N));
2973
2974 elsif Nkind (N) = N_Case_Statement then
2975 declare
2976 Alt : Node_Id;
2977 begin
2978 Alt := First (Alternatives (N));
2979 while Present (Alt) loop
2980 Kill_Dead_Code (Statements (Alt));
2981 Next (Alt);
2982 end loop;
2983 end;
2984
2985 elsif Nkind (N) = N_Case_Statement_Alternative then
2986 Kill_Dead_Code (Statements (N));
2987
2988 -- Deal with dead instances caused by deleting instantiations
2989
2990 elsif Nkind (N) in N_Generic_Instantiation then
2991 Remove_Dead_Instance (N);
2992 end if;
2993
2994 Delete_Tree (N);
2995 end if;
2996 end Kill_Dead_Code;
2997
2998 -- Case where argument is a list of nodes to be killed
2999
3000 procedure Kill_Dead_Code (L : List_Id) is
3001 N : Node_Id;
3002
3003 begin
3004 if Is_Non_Empty_List (L) then
3005 loop
3006 N := Remove_Head (L);
3007 exit when No (N);
3008 Kill_Dead_Code (N);
3009 end loop;
3010 end if;
3011 end Kill_Dead_Code;
3012
3013 ------------------------
3014 -- Known_Non_Negative --
3015 ------------------------
3016
3017 function Known_Non_Negative (Opnd : Node_Id) return Boolean is
3018 begin
3019 if Is_OK_Static_Expression (Opnd)
3020 and then Expr_Value (Opnd) >= 0
3021 then
3022 return True;
3023
3024 else
3025 declare
3026 Lo : constant Node_Id := Type_Low_Bound (Etype (Opnd));
3027
3028 begin
3029 return
3030 Is_OK_Static_Expression (Lo) and then Expr_Value (Lo) >= 0;
3031 end;
3032 end if;
3033 end Known_Non_Negative;
3034
3035 --------------------
3036 -- Known_Non_Null --
3037 --------------------
3038
3039 function Known_Non_Null (N : Node_Id) return Boolean is
3040 begin
3041 pragma Assert (Is_Access_Type (Underlying_Type (Etype (N))));
3042
3043 -- Case of entity for which Is_Known_Non_Null is True
3044
3045 if Is_Entity_Name (N) and then Is_Known_Non_Null (Entity (N)) then
3046
3047 -- If the entity is aliased or volatile, then we decide that
3048 -- we don't know it is really non-null even if the sequential
3049 -- flow indicates that it is, since such variables can be
3050 -- changed without us noticing.
3051
3052 if Is_Aliased (Entity (N))
3053 or else Treat_As_Volatile (Entity (N))
3054 then
3055 return False;
3056
3057 -- For all other cases, the flag is decisive
3058
3059 else
3060 return True;
3061 end if;
3062
3063 -- True if access attribute
3064
3065 elsif Nkind (N) = N_Attribute_Reference
3066 and then (Attribute_Name (N) = Name_Access
3067 or else
3068 Attribute_Name (N) = Name_Unchecked_Access
3069 or else
3070 Attribute_Name (N) = Name_Unrestricted_Access)
3071 then
3072 return True;
3073
3074 -- True if allocator
3075
3076 elsif Nkind (N) = N_Allocator then
3077 return True;
3078
3079 -- For a conversion, true if expression is known non-null
3080
3081 elsif Nkind (N) = N_Type_Conversion then
3082 return Known_Non_Null (Expression (N));
3083
3084 -- One more case is when Current_Value references a condition
3085 -- that ensures a non-null value.
3086
3087 elsif Is_Entity_Name (N) then
3088 declare
3089 Op : Node_Kind;
3090 Val : Node_Id;
3091
3092 begin
3093 Get_Current_Value_Condition (N, Op, Val);
3094 return Op = N_Op_Ne and then Nkind (Val) = N_Null;
3095 end;
3096
3097 -- Above are all cases where the value could be determined to be
3098 -- non-null. In all other cases, we don't know, so return False.
3099
3100 else
3101 return False;
3102 end if;
3103 end Known_Non_Null;
3104
3105 -----------------------------
3106 -- Make_CW_Equivalent_Type --
3107 -----------------------------
3108
3109 -- Create a record type used as an equivalent of any member
3110 -- of the class which takes its size from exp.
3111
3112 -- Generate the following code:
3113
3114 -- type Equiv_T is record
3115 -- _parent : T (List of discriminant constaints taken from Exp);
3116 -- Ext__50 : Storage_Array (1 .. (Exp'size - Typ'object_size)/8);
3117 -- end Equiv_T;
3118 --
3119 -- ??? Note that this type does not guarantee same alignment as all
3120 -- derived types
3121
3122 function Make_CW_Equivalent_Type
3123 (T : Entity_Id;
3124 E : Node_Id) return Entity_Id
3125 is
3126 Loc : constant Source_Ptr := Sloc (E);
3127 Root_Typ : constant Entity_Id := Root_Type (T);
3128 List_Def : constant List_Id := Empty_List;
3129 Equiv_Type : Entity_Id;
3130 Range_Type : Entity_Id;
3131 Str_Type : Entity_Id;
3132 Constr_Root : Entity_Id;
3133 Sizexpr : Node_Id;
3134
3135 begin
3136 if not Has_Discriminants (Root_Typ) then
3137 Constr_Root := Root_Typ;
3138 else
3139 Constr_Root :=
3140 Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
3141
3142 -- subtype cstr__n is T (List of discr constraints taken from Exp)
3143
3144 Append_To (List_Def,
3145 Make_Subtype_Declaration (Loc,
3146 Defining_Identifier => Constr_Root,
3147 Subtype_Indication =>
3148 Make_Subtype_From_Expr (E, Root_Typ)));
3149 end if;
3150
3151 -- subtype rg__xx is Storage_Offset range
3152 -- (Expr'size - typ'size) / Storage_Unit
3153
3154 Range_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('G'));
3155
3156 Sizexpr :=
3157 Make_Op_Subtract (Loc,
3158 Left_Opnd =>
3159 Make_Attribute_Reference (Loc,
3160 Prefix =>
3161 OK_Convert_To (T, Duplicate_Subexpr_No_Checks (E)),
3162 Attribute_Name => Name_Size),
3163 Right_Opnd =>
3164 Make_Attribute_Reference (Loc,
3165 Prefix => New_Reference_To (Constr_Root, Loc),
3166 Attribute_Name => Name_Object_Size));
3167
3168 Set_Paren_Count (Sizexpr, 1);
3169
3170 Append_To (List_Def,
3171 Make_Subtype_Declaration (Loc,
3172 Defining_Identifier => Range_Type,
3173 Subtype_Indication =>
3174 Make_Subtype_Indication (Loc,
3175 Subtype_Mark => New_Reference_To (RTE (RE_Storage_Offset), Loc),
3176 Constraint => Make_Range_Constraint (Loc,
3177 Range_Expression =>
3178 Make_Range (Loc,
3179 Low_Bound => Make_Integer_Literal (Loc, 1),
3180 High_Bound =>
3181 Make_Op_Divide (Loc,
3182 Left_Opnd => Sizexpr,
3183 Right_Opnd => Make_Integer_Literal (Loc,
3184 Intval => System_Storage_Unit)))))));
3185
3186 -- subtype str__nn is Storage_Array (rg__x);
3187
3188 Str_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('S'));
3189 Append_To (List_Def,
3190 Make_Subtype_Declaration (Loc,
3191 Defining_Identifier => Str_Type,
3192 Subtype_Indication =>
3193 Make_Subtype_Indication (Loc,
3194 Subtype_Mark => New_Reference_To (RTE (RE_Storage_Array), Loc),
3195 Constraint =>
3196 Make_Index_Or_Discriminant_Constraint (Loc,
3197 Constraints =>
3198 New_List (New_Reference_To (Range_Type, Loc))))));
3199
3200 -- type Equiv_T is record
3201 -- _parent : Tnn;
3202 -- E : Str_Type;
3203 -- end Equiv_T;
3204
3205 Equiv_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('T'));
3206
3207 -- When the target requires front-end layout, it's necessary to allow
3208 -- the equivalent type to be frozen so that layout can occur (when the
3209 -- associated class-wide subtype is frozen, the equivalent type will
3210 -- be frozen, see freeze.adb). For other targets, Gigi wants to have
3211 -- the equivalent type marked as frozen and deals with this type itself.
3212 -- In the Gigi case this will also avoid the generation of an init
3213 -- procedure for the type.
3214
3215 if not Frontend_Layout_On_Target then
3216 Set_Is_Frozen (Equiv_Type);
3217 end if;
3218
3219 Set_Ekind (Equiv_Type, E_Record_Type);
3220 Set_Parent_Subtype (Equiv_Type, Constr_Root);
3221
3222 Append_To (List_Def,
3223 Make_Full_Type_Declaration (Loc,
3224 Defining_Identifier => Equiv_Type,
3225
3226 Type_Definition =>
3227 Make_Record_Definition (Loc,
3228 Component_List => Make_Component_List (Loc,
3229 Component_Items => New_List (
3230 Make_Component_Declaration (Loc,
3231 Defining_Identifier =>
3232 Make_Defining_Identifier (Loc, Name_uParent),
3233 Component_Definition =>
3234 Make_Component_Definition (Loc,
3235 Aliased_Present => False,
3236 Subtype_Indication =>
3237 New_Reference_To (Constr_Root, Loc))),
3238
3239 Make_Component_Declaration (Loc,
3240 Defining_Identifier =>
3241 Make_Defining_Identifier (Loc,
3242 Chars => New_Internal_Name ('C')),
3243 Component_Definition =>
3244 Make_Component_Definition (Loc,
3245 Aliased_Present => False,
3246 Subtype_Indication =>
3247 New_Reference_To (Str_Type, Loc)))),
3248
3249 Variant_Part => Empty))));
3250
3251 Insert_Actions (E, List_Def);
3252 return Equiv_Type;
3253 end Make_CW_Equivalent_Type;
3254
3255 ------------------------
3256 -- Make_Literal_Range --
3257 ------------------------
3258
3259 function Make_Literal_Range
3260 (Loc : Source_Ptr;
3261 Literal_Typ : Entity_Id) return Node_Id
3262 is
3263 Lo : constant Node_Id :=
3264 New_Copy_Tree (String_Literal_Low_Bound (Literal_Typ));
3265
3266 begin
3267 Set_Analyzed (Lo, False);
3268
3269 return
3270 Make_Range (Loc,
3271 Low_Bound => Lo,
3272
3273 High_Bound =>
3274 Make_Op_Subtract (Loc,
3275 Left_Opnd =>
3276 Make_Op_Add (Loc,
3277 Left_Opnd => New_Copy_Tree (Lo),
3278 Right_Opnd =>
3279 Make_Integer_Literal (Loc,
3280 String_Literal_Length (Literal_Typ))),
3281 Right_Opnd => Make_Integer_Literal (Loc, 1)));
3282 end Make_Literal_Range;
3283
3284 ----------------------------
3285 -- Make_Subtype_From_Expr --
3286 ----------------------------
3287
3288 -- 1. If Expr is an uncontrained array expression, creates
3289 -- Unc_Type(Expr'first(1)..Expr'Last(1),..., Expr'first(n)..Expr'last(n))
3290
3291 -- 2. If Expr is a unconstrained discriminated type expression, creates
3292 -- Unc_Type(Expr.Discr1, ... , Expr.Discr_n)
3293
3294 -- 3. If Expr is class-wide, creates an implicit class wide subtype
3295
3296 function Make_Subtype_From_Expr
3297 (E : Node_Id;
3298 Unc_Typ : Entity_Id) return Node_Id
3299 is
3300 Loc : constant Source_Ptr := Sloc (E);
3301 List_Constr : constant List_Id := New_List;
3302 D : Entity_Id;
3303
3304 Full_Subtyp : Entity_Id;
3305 Priv_Subtyp : Entity_Id;
3306 Utyp : Entity_Id;
3307 Full_Exp : Node_Id;
3308
3309 begin
3310 if Is_Private_Type (Unc_Typ)
3311 and then Has_Unknown_Discriminants (Unc_Typ)
3312 then
3313 -- Prepare the subtype completion, Go to base type to
3314 -- find underlying type.
3315
3316 Utyp := Underlying_Type (Base_Type (Unc_Typ));
3317 Full_Subtyp := Make_Defining_Identifier (Loc,
3318 New_Internal_Name ('C'));
3319 Full_Exp :=
3320 Unchecked_Convert_To
3321 (Utyp, Duplicate_Subexpr_No_Checks (E));
3322 Set_Parent (Full_Exp, Parent (E));
3323
3324 Priv_Subtyp :=
3325 Make_Defining_Identifier (Loc, New_Internal_Name ('P'));
3326
3327 Insert_Action (E,
3328 Make_Subtype_Declaration (Loc,
3329 Defining_Identifier => Full_Subtyp,
3330 Subtype_Indication => Make_Subtype_From_Expr (Full_Exp, Utyp)));
3331
3332 -- Define the dummy private subtype
3333
3334 Set_Ekind (Priv_Subtyp, Subtype_Kind (Ekind (Unc_Typ)));
3335 Set_Etype (Priv_Subtyp, Unc_Typ);
3336 Set_Scope (Priv_Subtyp, Full_Subtyp);
3337 Set_Is_Constrained (Priv_Subtyp);
3338 Set_Is_Tagged_Type (Priv_Subtyp, Is_Tagged_Type (Unc_Typ));
3339 Set_Is_Itype (Priv_Subtyp);
3340 Set_Associated_Node_For_Itype (Priv_Subtyp, E);
3341
3342 if Is_Tagged_Type (Priv_Subtyp) then
3343 Set_Class_Wide_Type
3344 (Base_Type (Priv_Subtyp), Class_Wide_Type (Unc_Typ));
3345 Set_Primitive_Operations (Priv_Subtyp,
3346 Primitive_Operations (Unc_Typ));
3347 end if;
3348
3349 Set_Full_View (Priv_Subtyp, Full_Subtyp);
3350
3351 return New_Reference_To (Priv_Subtyp, Loc);
3352
3353 elsif Is_Array_Type (Unc_Typ) then
3354 for J in 1 .. Number_Dimensions (Unc_Typ) loop
3355 Append_To (List_Constr,
3356 Make_Range (Loc,
3357 Low_Bound =>
3358 Make_Attribute_Reference (Loc,
3359 Prefix => Duplicate_Subexpr_No_Checks (E),
3360 Attribute_Name => Name_First,
3361 Expressions => New_List (
3362 Make_Integer_Literal (Loc, J))),
3363
3364 High_Bound =>
3365 Make_Attribute_Reference (Loc,
3366 Prefix => Duplicate_Subexpr_No_Checks (E),
3367 Attribute_Name => Name_Last,
3368 Expressions => New_List (
3369 Make_Integer_Literal (Loc, J)))));
3370 end loop;
3371
3372 elsif Is_Class_Wide_Type (Unc_Typ) then
3373 declare
3374 CW_Subtype : Entity_Id;
3375 EQ_Typ : Entity_Id := Empty;
3376
3377 begin
3378 -- A class-wide equivalent type is not needed when Java_VM
3379 -- because the JVM back end handles the class-wide object
3380 -- initialization itself (and doesn't need or want the
3381 -- additional intermediate type to handle the assignment).
3382
3383 if Expander_Active and then not Java_VM then
3384 EQ_Typ := Make_CW_Equivalent_Type (Unc_Typ, E);
3385 end if;
3386
3387 CW_Subtype := New_Class_Wide_Subtype (Unc_Typ, E);
3388 Set_Equivalent_Type (CW_Subtype, EQ_Typ);
3389
3390 if Present (EQ_Typ) then
3391 Set_Is_Class_Wide_Equivalent_Type (EQ_Typ);
3392 end if;
3393
3394 Set_Cloned_Subtype (CW_Subtype, Base_Type (Unc_Typ));
3395
3396 return New_Occurrence_Of (CW_Subtype, Loc);
3397 end;
3398
3399 -- Comment needed (what case is this ???)
3400
3401 else
3402 D := First_Discriminant (Unc_Typ);
3403 while Present (D) loop
3404 Append_To (List_Constr,
3405 Make_Selected_Component (Loc,
3406 Prefix => Duplicate_Subexpr_No_Checks (E),
3407 Selector_Name => New_Reference_To (D, Loc)));
3408
3409 Next_Discriminant (D);
3410 end loop;
3411 end if;
3412
3413 return
3414 Make_Subtype_Indication (Loc,
3415 Subtype_Mark => New_Reference_To (Unc_Typ, Loc),
3416 Constraint =>
3417 Make_Index_Or_Discriminant_Constraint (Loc,
3418 Constraints => List_Constr));
3419 end Make_Subtype_From_Expr;
3420
3421 -----------------------------
3422 -- May_Generate_Large_Temp --
3423 -----------------------------
3424
3425 -- At the current time, the only types that we return False for (i.e.
3426 -- where we decide we know they cannot generate large temps) are ones
3427 -- where we know the size is 256 bits or less at compile time, and we
3428 -- are still not doing a thorough job on arrays and records ???
3429
3430 function May_Generate_Large_Temp (Typ : Entity_Id) return Boolean is
3431 begin
3432 if not Size_Known_At_Compile_Time (Typ) then
3433 return False;
3434
3435 elsif Esize (Typ) /= 0 and then Esize (Typ) <= 256 then
3436 return False;
3437
3438 elsif Is_Array_Type (Typ)
3439 and then Present (Packed_Array_Type (Typ))
3440 then
3441 return May_Generate_Large_Temp (Packed_Array_Type (Typ));
3442
3443 -- We could do more here to find other small types ???
3444
3445 else
3446 return True;
3447 end if;
3448 end May_Generate_Large_Temp;
3449
3450 ----------------------------
3451 -- New_Class_Wide_Subtype --
3452 ----------------------------
3453
3454 function New_Class_Wide_Subtype
3455 (CW_Typ : Entity_Id;
3456 N : Node_Id) return Entity_Id
3457 is
3458 Res : constant Entity_Id := Create_Itype (E_Void, N);
3459 Res_Name : constant Name_Id := Chars (Res);
3460 Res_Scope : constant Entity_Id := Scope (Res);
3461
3462 begin
3463 Copy_Node (CW_Typ, Res);
3464 Set_Sloc (Res, Sloc (N));
3465 Set_Is_Itype (Res);
3466 Set_Associated_Node_For_Itype (Res, N);
3467 Set_Is_Public (Res, False); -- By default, may be changed below.
3468 Set_Public_Status (Res);
3469 Set_Chars (Res, Res_Name);
3470 Set_Scope (Res, Res_Scope);
3471 Set_Ekind (Res, E_Class_Wide_Subtype);
3472 Set_Next_Entity (Res, Empty);
3473 Set_Etype (Res, Base_Type (CW_Typ));
3474
3475 -- For targets where front-end layout is required, reset the Is_Frozen
3476 -- status of the subtype to False (it can be implicitly set to true
3477 -- from the copy of the class-wide type). For other targets, Gigi
3478 -- doesn't want the class-wide subtype to go through the freezing
3479 -- process (though it's unclear why that causes problems and it would
3480 -- be nice to allow freezing to occur normally for all targets ???).
3481
3482 if Frontend_Layout_On_Target then
3483 Set_Is_Frozen (Res, False);
3484 end if;
3485
3486 Set_Freeze_Node (Res, Empty);
3487 return (Res);
3488 end New_Class_Wide_Subtype;
3489
3490 -------------------------
3491 -- Remove_Side_Effects --
3492 -------------------------
3493
3494 procedure Remove_Side_Effects
3495 (Exp : Node_Id;
3496 Name_Req : Boolean := False;
3497 Variable_Ref : Boolean := False)
3498 is
3499 Loc : constant Source_Ptr := Sloc (Exp);
3500 Exp_Type : constant Entity_Id := Etype (Exp);
3501 Svg_Suppress : constant Suppress_Array := Scope_Suppress;
3502 Def_Id : Entity_Id;
3503 Ref_Type : Entity_Id;
3504 Res : Node_Id;
3505 Ptr_Typ_Decl : Node_Id;
3506 New_Exp : Node_Id;
3507 E : Node_Id;
3508
3509 function Side_Effect_Free (N : Node_Id) return Boolean;
3510 -- Determines if the tree N represents an expression that is known
3511 -- not to have side effects, and for which no processing is required.
3512
3513 function Side_Effect_Free (L : List_Id) return Boolean;
3514 -- Determines if all elements of the list L are side effect free
3515
3516 function Safe_Prefixed_Reference (N : Node_Id) return Boolean;
3517 -- The argument N is a construct where the Prefix is dereferenced
3518 -- if it is a an access type and the result is a variable. The call
3519 -- returns True if the construct is side effect free (not considering
3520 -- side effects in other than the prefix which are to be tested by the
3521 -- caller).
3522
3523 function Within_In_Parameter (N : Node_Id) return Boolean;
3524 -- Determines if N is a subcomponent of a composite in-parameter.
3525 -- If so, N is not side-effect free when the actual is global and
3526 -- modifiable indirectly from within a subprogram, because it may
3527 -- be passed by reference. The front-end must be conservative here
3528 -- and assume that this may happen with any array or record type.
3529 -- On the other hand, we cannot create temporaries for all expressions
3530 -- for which this condition is true, for various reasons that might
3531 -- require clearing up ??? For example, descriminant references that
3532 -- appear out of place, or spurious type errors with class-wide
3533 -- expressions. As a result, we limit the transformation to loop
3534 -- bounds, which is so far the only case that requires it.
3535
3536 -----------------------------
3537 -- Safe_Prefixed_Reference --
3538 -----------------------------
3539
3540 function Safe_Prefixed_Reference (N : Node_Id) return Boolean is
3541 begin
3542 -- If prefix is not side effect free, definitely not safe
3543
3544 if not Side_Effect_Free (Prefix (N)) then
3545 return False;
3546
3547 -- If the prefix is of an access type that is not access-to-constant,
3548 -- then this construct is a variable reference, which means it is to
3549 -- be considered to have side effects if Variable_Ref is set True
3550 -- Exception is an access to an entity that is a constant or an
3551 -- in-parameter which does not come from source, and is the result
3552 -- of a previous removal of side-effects.
3553
3554 elsif Is_Access_Type (Etype (Prefix (N)))
3555 and then not Is_Access_Constant (Etype (Prefix (N)))
3556 and then Variable_Ref
3557 then
3558 if not Is_Entity_Name (Prefix (N)) then
3559 return False;
3560 else
3561 return Ekind (Entity (Prefix (N))) = E_Constant
3562 or else Ekind (Entity (Prefix (N))) = E_In_Parameter;
3563 end if;
3564
3565 -- The following test is the simplest way of solving a complex
3566 -- problem uncovered by BB08-010: Side effect on loop bound that
3567 -- is a subcomponent of a global variable:
3568 -- If a loop bound is a subcomponent of a global variable, a
3569 -- modification of that variable within the loop may incorrectly
3570 -- affect the execution of the loop.
3571
3572 elsif not
3573 (Nkind (Parent (Parent (N))) /= N_Loop_Parameter_Specification
3574 or else not Within_In_Parameter (Prefix (N)))
3575 then
3576 return False;
3577
3578 -- All other cases are side effect free
3579
3580 else
3581 return True;
3582 end if;
3583 end Safe_Prefixed_Reference;
3584
3585 ----------------------
3586 -- Side_Effect_Free --
3587 ----------------------
3588
3589 function Side_Effect_Free (N : Node_Id) return Boolean is
3590 begin
3591 -- Note on checks that could raise Constraint_Error. Strictly, if
3592 -- we take advantage of 11.6, these checks do not count as side
3593 -- effects. However, we would just as soon consider that they are
3594 -- side effects, since the backend CSE does not work very well on
3595 -- expressions which can raise Constraint_Error. On the other
3596 -- hand, if we do not consider them to be side effect free, then
3597 -- we get some awkward expansions in -gnato mode, resulting in
3598 -- code insertions at a point where we do not have a clear model
3599 -- for performing the insertions. See 4908-002/comment for details.
3600
3601 -- Special handling for entity names
3602
3603 if Is_Entity_Name (N) then
3604
3605 -- If the entity is a constant, it is definitely side effect
3606 -- free. Note that the test of Is_Variable (N) below might
3607 -- be expected to catch this case, but it does not, because
3608 -- this test goes to the original tree, and we may have
3609 -- already rewritten a variable node with a constant as
3610 -- a result of an earlier Force_Evaluation call.
3611
3612 if Ekind (Entity (N)) = E_Constant
3613 or else Ekind (Entity (N)) = E_In_Parameter
3614 then
3615 return True;
3616
3617 -- Functions are not side effect free
3618
3619 elsif Ekind (Entity (N)) = E_Function then
3620 return False;
3621
3622 -- Variables are considered to be a side effect if Variable_Ref
3623 -- is set or if we have a volatile variable and Name_Req is off.
3624 -- If Name_Req is True then we can't help returning a name which
3625 -- effectively allows multiple references in any case.
3626
3627 elsif Is_Variable (N) then
3628 return not Variable_Ref
3629 and then (not Treat_As_Volatile (Entity (N))
3630 or else Name_Req);
3631
3632 -- Any other entity (e.g. a subtype name) is definitely side
3633 -- effect free.
3634
3635 else
3636 return True;
3637 end if;
3638
3639 -- A value known at compile time is always side effect free
3640
3641 elsif Compile_Time_Known_Value (N) then
3642 return True;
3643 end if;
3644
3645 -- For other than entity names and compile time known values,
3646 -- check the node kind for special processing.
3647
3648 case Nkind (N) is
3649
3650 -- An attribute reference is side effect free if its expressions
3651 -- are side effect free and its prefix is side effect free or
3652 -- is an entity reference.
3653
3654 -- Is this right? what about x'first where x is a variable???
3655
3656 when N_Attribute_Reference =>
3657 return Side_Effect_Free (Expressions (N))
3658 and then (Is_Entity_Name (Prefix (N))
3659 or else Side_Effect_Free (Prefix (N)));
3660
3661 -- A binary operator is side effect free if and both operands
3662 -- are side effect free. For this purpose binary operators
3663 -- include membership tests and short circuit forms
3664
3665 when N_Binary_Op |
3666 N_In |
3667 N_Not_In |
3668 N_And_Then |
3669 N_Or_Else =>
3670 return Side_Effect_Free (Left_Opnd (N))
3671 and then Side_Effect_Free (Right_Opnd (N));
3672
3673 -- An explicit dereference is side effect free only if it is
3674 -- a side effect free prefixed reference.
3675
3676 when N_Explicit_Dereference =>
3677 return Safe_Prefixed_Reference (N);
3678
3679 -- A call to _rep_to_pos is side effect free, since we generate
3680 -- this pure function call ourselves. Moreover it is critically
3681 -- important to make this exception, since otherwise we can
3682 -- have discriminants in array components which don't look
3683 -- side effect free in the case of an array whose index type
3684 -- is an enumeration type with an enumeration rep clause.
3685
3686 -- All other function calls are not side effect free
3687
3688 when N_Function_Call =>
3689 return Nkind (Name (N)) = N_Identifier
3690 and then Is_TSS (Name (N), TSS_Rep_To_Pos)
3691 and then
3692 Side_Effect_Free (First (Parameter_Associations (N)));
3693
3694 -- An indexed component is side effect free if it is a side
3695 -- effect free prefixed reference and all the indexing
3696 -- expressions are side effect free.
3697
3698 when N_Indexed_Component =>
3699 return Side_Effect_Free (Expressions (N))
3700 and then Safe_Prefixed_Reference (N);
3701
3702 -- A type qualification is side effect free if the expression
3703 -- is side effect free.
3704
3705 when N_Qualified_Expression =>
3706 return Side_Effect_Free (Expression (N));
3707
3708 -- A selected component is side effect free only if it is a
3709 -- side effect free prefixed reference.
3710
3711 when N_Selected_Component =>
3712 return Safe_Prefixed_Reference (N);
3713
3714 -- A range is side effect free if the bounds are side effect free
3715
3716 when N_Range =>
3717 return Side_Effect_Free (Low_Bound (N))
3718 and then Side_Effect_Free (High_Bound (N));
3719
3720 -- A slice is side effect free if it is a side effect free
3721 -- prefixed reference and the bounds are side effect free.
3722
3723 when N_Slice =>
3724 return Side_Effect_Free (Discrete_Range (N))
3725 and then Safe_Prefixed_Reference (N);
3726
3727 -- A type conversion is side effect free if the expression
3728 -- to be converted is side effect free.
3729
3730 when N_Type_Conversion =>
3731 return Side_Effect_Free (Expression (N));
3732
3733 -- A unary operator is side effect free if the operand
3734 -- is side effect free.
3735
3736 when N_Unary_Op =>
3737 return Side_Effect_Free (Right_Opnd (N));
3738
3739 -- An unchecked type conversion is side effect free only if it
3740 -- is safe and its argument is side effect free.
3741
3742 when N_Unchecked_Type_Conversion =>
3743 return Safe_Unchecked_Type_Conversion (N)
3744 and then Side_Effect_Free (Expression (N));
3745
3746 -- An unchecked expression is side effect free if its expression
3747 -- is side effect free.
3748
3749 when N_Unchecked_Expression =>
3750 return Side_Effect_Free (Expression (N));
3751
3752 -- A literal is side effect free
3753
3754 when N_Character_Literal |
3755 N_Integer_Literal |
3756 N_Real_Literal |
3757 N_String_Literal =>
3758 return True;
3759
3760 -- We consider that anything else has side effects. This is a bit
3761 -- crude, but we are pretty close for most common cases, and we
3762 -- are certainly correct (i.e. we never return True when the
3763 -- answer should be False).
3764
3765 when others =>
3766 return False;
3767 end case;
3768 end Side_Effect_Free;
3769
3770 -- A list is side effect free if all elements of the list are
3771 -- side effect free.
3772
3773 function Side_Effect_Free (L : List_Id) return Boolean is
3774 N : Node_Id;
3775
3776 begin
3777 if L = No_List or else L = Error_List then
3778 return True;
3779
3780 else
3781 N := First (L);
3782 while Present (N) loop
3783 if not Side_Effect_Free (N) then
3784 return False;
3785 else
3786 Next (N);
3787 end if;
3788 end loop;
3789
3790 return True;
3791 end if;
3792 end Side_Effect_Free;
3793
3794 -------------------------
3795 -- Within_In_Parameter --
3796 -------------------------
3797
3798 function Within_In_Parameter (N : Node_Id) return Boolean is
3799 begin
3800 if not Comes_From_Source (N) then
3801 return False;
3802
3803 elsif Is_Entity_Name (N) then
3804 return
3805 Ekind (Entity (N)) = E_In_Parameter;
3806
3807 elsif Nkind (N) = N_Indexed_Component
3808 or else Nkind (N) = N_Selected_Component
3809 then
3810 return Within_In_Parameter (Prefix (N));
3811 else
3812
3813 return False;
3814 end if;
3815 end Within_In_Parameter;
3816
3817 -- Start of processing for Remove_Side_Effects
3818
3819 begin
3820 -- If we are side effect free already or expansion is disabled,
3821 -- there is nothing to do.
3822
3823 if Side_Effect_Free (Exp) or else not Expander_Active then
3824 return;
3825 end if;
3826
3827 -- All this must not have any checks
3828
3829 Scope_Suppress := (others => True);
3830
3831 -- If the expression has the form v.all then we can just capture
3832 -- the pointer, and then do an explicit dereference on the result.
3833
3834 if Nkind (Exp) = N_Explicit_Dereference then
3835 Def_Id :=
3836 Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
3837 Res :=
3838 Make_Explicit_Dereference (Loc, New_Reference_To (Def_Id, Loc));
3839
3840 Insert_Action (Exp,
3841 Make_Object_Declaration (Loc,
3842 Defining_Identifier => Def_Id,
3843 Object_Definition =>
3844 New_Reference_To (Etype (Prefix (Exp)), Loc),
3845 Constant_Present => True,
3846 Expression => Relocate_Node (Prefix (Exp))));
3847
3848 -- Similar processing for an unchecked conversion of an expression
3849 -- of the form v.all, where we want the same kind of treatment.
3850
3851 elsif Nkind (Exp) = N_Unchecked_Type_Conversion
3852 and then Nkind (Expression (Exp)) = N_Explicit_Dereference
3853 then
3854 Remove_Side_Effects (Expression (Exp), Name_Req, Variable_Ref);
3855 Scope_Suppress := Svg_Suppress;
3856 return;
3857
3858 -- If this is a type conversion, leave the type conversion and remove
3859 -- the side effects in the expression. This is important in several
3860 -- circumstances: for change of representations, and also when this
3861 -- is a view conversion to a smaller object, where gigi can end up
3862 -- creating its own temporary of the wrong size.
3863
3864 -- ??? this transformation is inhibited for elementary types that are
3865 -- not involved in a change of representation because it causes
3866 -- regressions that are not fully understood yet.
3867
3868 elsif Nkind (Exp) = N_Type_Conversion
3869 and then (not Is_Elementary_Type (Underlying_Type (Exp_Type))
3870 or else Nkind (Parent (Exp)) = N_Assignment_Statement)
3871 then
3872 Remove_Side_Effects (Expression (Exp), Name_Req, Variable_Ref);
3873 Scope_Suppress := Svg_Suppress;
3874 return;
3875
3876 -- For expressions that denote objects, we can use a renaming scheme.
3877 -- We skip using this if we have a volatile variable and we do not
3878 -- have Nam_Req set true (see comments above for Side_Effect_Free).
3879 -- We also skip this scheme for class-wide expressions in order to
3880 -- avoid recursive expansion (see Expand_N_Object_Renaming_Declaration)
3881 -- If the object is a function call, we need to create a temporary and
3882 -- not a renaming.
3883
3884 -- Note that we could use ordinary object declarations in the case of
3885 -- expressions not appearing as lvalues. That is left as a possible
3886 -- optimization in the future but we prefer to generate renamings
3887 -- right now, since we may indeed be transforming an lvalue.
3888
3889 elsif Is_Object_Reference (Exp)
3890 and then Nkind (Exp) /= N_Function_Call
3891 and then not Variable_Ref
3892 and then (Name_Req
3893 or else not Is_Entity_Name (Exp)
3894 or else not Treat_As_Volatile (Entity (Exp)))
3895 and then not Is_Class_Wide_Type (Exp_Type)
3896 then
3897 Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
3898
3899 if Nkind (Exp) = N_Selected_Component
3900 and then Nkind (Prefix (Exp)) = N_Function_Call
3901 and then Is_Array_Type (Etype (Exp))
3902 then
3903 -- Avoid generating a variable-sized temporary, by generating
3904 -- the renaming declaration just for the function call. The
3905 -- transformation could be refined to apply only when the array
3906 -- component is constrained by a discriminant???
3907
3908 Res :=
3909 Make_Selected_Component (Loc,
3910 Prefix => New_Occurrence_Of (Def_Id, Loc),
3911 Selector_Name => Selector_Name (Exp));
3912
3913 Insert_Action (Exp,
3914 Make_Object_Renaming_Declaration (Loc,
3915 Defining_Identifier => Def_Id,
3916 Subtype_Mark =>
3917 New_Reference_To (Base_Type (Etype (Prefix (Exp))), Loc),
3918 Name => Relocate_Node (Prefix (Exp))));
3919
3920 -- The temporary must be elaborated by gigi, and is of course
3921 -- not to be replaced in-line by the expression it renames,
3922 -- which would defeat the purpose of removing the side-effect.
3923
3924 Set_Is_Renaming_Of_Object (Def_Id, False);
3925
3926 else
3927 Res := New_Reference_To (Def_Id, Loc);
3928
3929 Insert_Action (Exp,
3930 Make_Object_Renaming_Declaration (Loc,
3931 Defining_Identifier => Def_Id,
3932 Subtype_Mark => New_Reference_To (Exp_Type, Loc),
3933 Name => Relocate_Node (Exp)));
3934
3935 Set_Is_Renaming_Of_Object (Def_Id, False);
3936 end if;
3937
3938 -- If it is a scalar type, just make a copy
3939
3940 elsif Is_Elementary_Type (Exp_Type) then
3941 Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
3942 Set_Etype (Def_Id, Exp_Type);
3943 Res := New_Reference_To (Def_Id, Loc);
3944
3945 E :=
3946 Make_Object_Declaration (Loc,
3947 Defining_Identifier => Def_Id,
3948 Object_Definition => New_Reference_To (Exp_Type, Loc),
3949 Constant_Present => True,
3950 Expression => Relocate_Node (Exp));
3951
3952 Set_Assignment_OK (E);
3953 Insert_Action (Exp, E);
3954
3955 -- Always use a renaming for an unchecked conversion
3956 -- If this is an unchecked conversion that Gigi can't handle, make
3957 -- a copy or a use a renaming to capture the value.
3958
3959 elsif Nkind (Exp) = N_Unchecked_Type_Conversion
3960 and then not Safe_Unchecked_Type_Conversion (Exp)
3961 then
3962 if Controlled_Type (Etype (Exp)) then
3963
3964 -- Use a renaming to capture the expression, rather than create
3965 -- a controlled temporary.
3966
3967 Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
3968 Res := New_Reference_To (Def_Id, Loc);
3969
3970 Insert_Action (Exp,
3971 Make_Object_Renaming_Declaration (Loc,
3972 Defining_Identifier => Def_Id,
3973 Subtype_Mark => New_Reference_To (Exp_Type, Loc),
3974 Name => Relocate_Node (Exp)));
3975
3976 else
3977 Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
3978 Set_Etype (Def_Id, Exp_Type);
3979 Res := New_Reference_To (Def_Id, Loc);
3980
3981 E :=
3982 Make_Object_Declaration (Loc,
3983 Defining_Identifier => Def_Id,
3984 Object_Definition => New_Reference_To (Exp_Type, Loc),
3985 Constant_Present => not Is_Variable (Exp),
3986 Expression => Relocate_Node (Exp));
3987
3988 Set_Assignment_OK (E);
3989 Insert_Action (Exp, E);
3990 end if;
3991
3992 -- Otherwise we generate a reference to the value
3993
3994 else
3995 Ref_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('A'));
3996
3997 Ptr_Typ_Decl :=
3998 Make_Full_Type_Declaration (Loc,
3999 Defining_Identifier => Ref_Type,
4000 Type_Definition =>
4001 Make_Access_To_Object_Definition (Loc,
4002 All_Present => True,
4003 Subtype_Indication =>
4004 New_Reference_To (Exp_Type, Loc)));
4005
4006 E := Exp;
4007 Insert_Action (Exp, Ptr_Typ_Decl);
4008
4009 Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
4010 Set_Etype (Def_Id, Exp_Type);
4011
4012 Res :=
4013 Make_Explicit_Dereference (Loc,
4014 Prefix => New_Reference_To (Def_Id, Loc));
4015
4016 if Nkind (E) = N_Explicit_Dereference then
4017 New_Exp := Relocate_Node (Prefix (E));
4018 else
4019 E := Relocate_Node (E);
4020 New_Exp := Make_Reference (Loc, E);
4021 end if;
4022
4023 if Is_Delayed_Aggregate (E) then
4024
4025 -- The expansion of nested aggregates is delayed until the
4026 -- enclosing aggregate is expanded. As aggregates are often
4027 -- qualified, the predicate applies to qualified expressions
4028 -- as well, indicating that the enclosing aggregate has not
4029 -- been expanded yet. At this point the aggregate is part of
4030 -- a stand-alone declaration, and must be fully expanded.
4031
4032 if Nkind (E) = N_Qualified_Expression then
4033 Set_Expansion_Delayed (Expression (E), False);
4034 Set_Analyzed (Expression (E), False);
4035 else
4036 Set_Expansion_Delayed (E, False);
4037 end if;
4038
4039 Set_Analyzed (E, False);
4040 end if;
4041
4042 Insert_Action (Exp,
4043 Make_Object_Declaration (Loc,
4044 Defining_Identifier => Def_Id,
4045 Object_Definition => New_Reference_To (Ref_Type, Loc),
4046 Expression => New_Exp));
4047 end if;
4048
4049 -- Preserve the Assignment_OK flag in all copies, since at least
4050 -- one copy may be used in a context where this flag must be set
4051 -- (otherwise why would the flag be set in the first place).
4052
4053 Set_Assignment_OK (Res, Assignment_OK (Exp));
4054
4055 -- Finally rewrite the original expression and we are done
4056
4057 Rewrite (Exp, Res);
4058 Analyze_And_Resolve (Exp, Exp_Type);
4059 Scope_Suppress := Svg_Suppress;
4060 end Remove_Side_Effects;
4061
4062 ---------------------------
4063 -- Represented_As_Scalar --
4064 ---------------------------
4065
4066 function Represented_As_Scalar (T : Entity_Id) return Boolean is
4067 UT : constant Entity_Id := Underlying_Type (T);
4068 begin
4069 return Is_Scalar_Type (UT)
4070 or else (Is_Bit_Packed_Array (UT)
4071 and then Is_Scalar_Type (Packed_Array_Type (UT)));
4072 end Represented_As_Scalar;
4073
4074 ------------------------------------
4075 -- Safe_Unchecked_Type_Conversion --
4076 ------------------------------------
4077
4078 -- Note: this function knows quite a bit about the exact requirements
4079 -- of Gigi with respect to unchecked type conversions, and its code
4080 -- must be coordinated with any changes in Gigi in this area.
4081
4082 -- The above requirements should be documented in Sinfo ???
4083
4084 function Safe_Unchecked_Type_Conversion (Exp : Node_Id) return Boolean is
4085 Otyp : Entity_Id;
4086 Ityp : Entity_Id;
4087 Oalign : Uint;
4088 Ialign : Uint;
4089 Pexp : constant Node_Id := Parent (Exp);
4090
4091 begin
4092 -- If the expression is the RHS of an assignment or object declaration
4093 -- we are always OK because there will always be a target.
4094
4095 -- Object renaming declarations, (generated for view conversions of
4096 -- actuals in inlined calls), like object declarations, provide an
4097 -- explicit type, and are safe as well.
4098
4099 if (Nkind (Pexp) = N_Assignment_Statement
4100 and then Expression (Pexp) = Exp)
4101 or else Nkind (Pexp) = N_Object_Declaration
4102 or else Nkind (Pexp) = N_Object_Renaming_Declaration
4103 then
4104 return True;
4105
4106 -- If the expression is the prefix of an N_Selected_Component
4107 -- we should also be OK because GCC knows to look inside the
4108 -- conversion except if the type is discriminated. We assume
4109 -- that we are OK anyway if the type is not set yet or if it is
4110 -- controlled since we can't afford to introduce a temporary in
4111 -- this case.
4112
4113 elsif Nkind (Pexp) = N_Selected_Component
4114 and then Prefix (Pexp) = Exp
4115 then
4116 if No (Etype (Pexp)) then
4117 return True;
4118 else
4119 return
4120 not Has_Discriminants (Etype (Pexp))
4121 or else Is_Constrained (Etype (Pexp));
4122 end if;
4123 end if;
4124
4125 -- Set the output type, this comes from Etype if it is set, otherwise
4126 -- we take it from the subtype mark, which we assume was already
4127 -- fully analyzed.
4128
4129 if Present (Etype (Exp)) then
4130 Otyp := Etype (Exp);
4131 else
4132 Otyp := Entity (Subtype_Mark (Exp));
4133 end if;
4134
4135 -- The input type always comes from the expression, and we assume
4136 -- this is indeed always analyzed, so we can simply get the Etype.
4137
4138 Ityp := Etype (Expression (Exp));
4139
4140 -- Initialize alignments to unknown so far
4141
4142 Oalign := No_Uint;
4143 Ialign := No_Uint;
4144
4145 -- Replace a concurrent type by its corresponding record type
4146 -- and each type by its underlying type and do the tests on those.
4147 -- The original type may be a private type whose completion is a
4148 -- concurrent type, so find the underlying type first.
4149
4150 if Present (Underlying_Type (Otyp)) then
4151 Otyp := Underlying_Type (Otyp);
4152 end if;
4153
4154 if Present (Underlying_Type (Ityp)) then
4155 Ityp := Underlying_Type (Ityp);
4156 end if;
4157
4158 if Is_Concurrent_Type (Otyp) then
4159 Otyp := Corresponding_Record_Type (Otyp);
4160 end if;
4161
4162 if Is_Concurrent_Type (Ityp) then
4163 Ityp := Corresponding_Record_Type (Ityp);
4164 end if;
4165
4166 -- If the base types are the same, we know there is no problem since
4167 -- this conversion will be a noop.
4168
4169 if Implementation_Base_Type (Otyp) = Implementation_Base_Type (Ityp) then
4170 return True;
4171
4172 -- Same if this is an upwards conversion of an untagged type, and there
4173 -- are no constraints involved (could be more general???)
4174
4175 elsif Etype (Ityp) = Otyp
4176 and then not Is_Tagged_Type (Ityp)
4177 and then not Has_Discriminants (Ityp)
4178 and then No (First_Rep_Item (Base_Type (Ityp)))
4179 then
4180 return True;
4181
4182 -- If the size of output type is known at compile time, there is
4183 -- never a problem. Note that unconstrained records are considered
4184 -- to be of known size, but we can't consider them that way here,
4185 -- because we are talking about the actual size of the object.
4186
4187 -- We also make sure that in addition to the size being known, we do
4188 -- not have a case which might generate an embarrassingly large temp
4189 -- in stack checking mode.
4190
4191 elsif Size_Known_At_Compile_Time (Otyp)
4192 and then
4193 (not Stack_Checking_Enabled
4194 or else not May_Generate_Large_Temp (Otyp))
4195 and then not (Is_Record_Type (Otyp) and then not Is_Constrained (Otyp))
4196 then
4197 return True;
4198
4199 -- If either type is tagged, then we know the alignment is OK so
4200 -- Gigi will be able to use pointer punning.
4201
4202 elsif Is_Tagged_Type (Otyp) or else Is_Tagged_Type (Ityp) then
4203 return True;
4204
4205 -- If either type is a limited record type, we cannot do a copy, so
4206 -- say safe since there's nothing else we can do.
4207
4208 elsif Is_Limited_Record (Otyp) or else Is_Limited_Record (Ityp) then
4209 return True;
4210
4211 -- Conversions to and from packed array types are always ignored and
4212 -- hence are safe.
4213
4214 elsif Is_Packed_Array_Type (Otyp)
4215 or else Is_Packed_Array_Type (Ityp)
4216 then
4217 return True;
4218 end if;
4219
4220 -- The only other cases known to be safe is if the input type's
4221 -- alignment is known to be at least the maximum alignment for the
4222 -- target or if both alignments are known and the output type's
4223 -- alignment is no stricter than the input's. We can use the alignment
4224 -- of the component type of an array if a type is an unpacked
4225 -- array type.
4226
4227 if Present (Alignment_Clause (Otyp)) then
4228 Oalign := Expr_Value (Expression (Alignment_Clause (Otyp)));
4229
4230 elsif Is_Array_Type (Otyp)
4231 and then Present (Alignment_Clause (Component_Type (Otyp)))
4232 then
4233 Oalign := Expr_Value (Expression (Alignment_Clause
4234 (Component_Type (Otyp))));
4235 end if;
4236
4237 if Present (Alignment_Clause (Ityp)) then
4238 Ialign := Expr_Value (Expression (Alignment_Clause (Ityp)));
4239
4240 elsif Is_Array_Type (Ityp)
4241 and then Present (Alignment_Clause (Component_Type (Ityp)))
4242 then
4243 Ialign := Expr_Value (Expression (Alignment_Clause
4244 (Component_Type (Ityp))));
4245 end if;
4246
4247 if Ialign /= No_Uint and then Ialign > Maximum_Alignment then
4248 return True;
4249
4250 elsif Ialign /= No_Uint and then Oalign /= No_Uint
4251 and then Ialign <= Oalign
4252 then
4253 return True;
4254
4255 -- Otherwise, Gigi cannot handle this and we must make a temporary
4256
4257 else
4258 return False;
4259 end if;
4260
4261 end Safe_Unchecked_Type_Conversion;
4262
4263 --------------------------
4264 -- Set_Elaboration_Flag --
4265 --------------------------
4266
4267 procedure Set_Elaboration_Flag (N : Node_Id; Spec_Id : Entity_Id) is
4268 Loc : constant Source_Ptr := Sloc (N);
4269 Ent : constant Entity_Id := Elaboration_Entity (Spec_Id);
4270 Asn : Node_Id;
4271
4272 begin
4273 if Present (Ent) then
4274
4275 -- Nothing to do if at the compilation unit level, because in this
4276 -- case the flag is set by the binder generated elaboration routine.
4277
4278 if Nkind (Parent (N)) = N_Compilation_Unit then
4279 null;
4280
4281 -- Here we do need to generate an assignment statement
4282
4283 else
4284 Check_Restriction (No_Elaboration_Code, N);
4285 Asn :=
4286 Make_Assignment_Statement (Loc,
4287 Name => New_Occurrence_Of (Ent, Loc),
4288 Expression => New_Occurrence_Of (Standard_True, Loc));
4289
4290 if Nkind (Parent (N)) = N_Subunit then
4291 Insert_After (Corresponding_Stub (Parent (N)), Asn);
4292 else
4293 Insert_After (N, Asn);
4294 end if;
4295
4296 Analyze (Asn);
4297
4298 -- Kill current value indication. This is necessary because
4299 -- the tests of this flag are inserted out of sequence and must
4300 -- not pick up bogus indications of the wrong constant value.
4301
4302 Set_Current_Value (Ent, Empty);
4303 end if;
4304 end if;
4305 end Set_Elaboration_Flag;
4306
4307 --------------------------
4308 -- Target_Has_Fixed_Ops --
4309 --------------------------
4310
4311 Integer_Sized_Small : Ureal;
4312 -- Set to 2.0 ** -(Integer'Size - 1) the first time that this
4313 -- function is called (we don't want to compute it more than once!)
4314
4315 Long_Integer_Sized_Small : Ureal;
4316 -- Set to 2.0 ** -(Long_Integer'Size - 1) the first time that this
4317 -- functoin is called (we don't want to compute it more than once)
4318
4319 First_Time_For_THFO : Boolean := True;
4320 -- Set to False after first call (if Fractional_Fixed_Ops_On_Target)
4321
4322 function Target_Has_Fixed_Ops
4323 (Left_Typ : Entity_Id;
4324 Right_Typ : Entity_Id;
4325 Result_Typ : Entity_Id) return Boolean
4326 is
4327 function Is_Fractional_Type (Typ : Entity_Id) return Boolean;
4328 -- Return True if the given type is a fixed-point type with a small
4329 -- value equal to 2 ** (-(T'Object_Size - 1)) and whose values have
4330 -- an absolute value less than 1.0. This is currently limited
4331 -- to fixed-point types that map to Integer or Long_Integer.
4332
4333 ------------------------
4334 -- Is_Fractional_Type --
4335 ------------------------
4336
4337 function Is_Fractional_Type (Typ : Entity_Id) return Boolean is
4338 begin
4339 if Esize (Typ) = Standard_Integer_Size then
4340 return Small_Value (Typ) = Integer_Sized_Small;
4341
4342 elsif Esize (Typ) = Standard_Long_Integer_Size then
4343 return Small_Value (Typ) = Long_Integer_Sized_Small;
4344
4345 else
4346 return False;
4347 end if;
4348 end Is_Fractional_Type;
4349
4350 -- Start of processing for Target_Has_Fixed_Ops
4351
4352 begin
4353 -- Return False if Fractional_Fixed_Ops_On_Target is false
4354
4355 if not Fractional_Fixed_Ops_On_Target then
4356 return False;
4357 end if;
4358
4359 -- Here the target has Fractional_Fixed_Ops, if first time, compute
4360 -- standard constants used by Is_Fractional_Type.
4361
4362 if First_Time_For_THFO then
4363 First_Time_For_THFO := False;
4364
4365 Integer_Sized_Small :=
4366 UR_From_Components
4367 (Num => Uint_1,
4368 Den => UI_From_Int (Standard_Integer_Size - 1),
4369 Rbase => 2);
4370
4371 Long_Integer_Sized_Small :=
4372 UR_From_Components
4373 (Num => Uint_1,
4374 Den => UI_From_Int (Standard_Long_Integer_Size - 1),
4375 Rbase => 2);
4376 end if;
4377
4378 -- Return True if target supports fixed-by-fixed multiply/divide
4379 -- for fractional fixed-point types (see Is_Fractional_Type) and
4380 -- the operand and result types are equivalent fractional types.
4381
4382 return Is_Fractional_Type (Base_Type (Left_Typ))
4383 and then Is_Fractional_Type (Base_Type (Right_Typ))
4384 and then Is_Fractional_Type (Base_Type (Result_Typ))
4385 and then Esize (Left_Typ) = Esize (Right_Typ)
4386 and then Esize (Left_Typ) = Esize (Result_Typ);
4387 end Target_Has_Fixed_Ops;
4388
4389 ------------------------------------------
4390 -- Type_May_Have_Bit_Aligned_Components --
4391 ------------------------------------------
4392
4393 function Type_May_Have_Bit_Aligned_Components
4394 (Typ : Entity_Id) return Boolean
4395 is
4396 begin
4397 -- Array type, check component type
4398
4399 if Is_Array_Type (Typ) then
4400 return
4401 Type_May_Have_Bit_Aligned_Components (Component_Type (Typ));
4402
4403 -- Record type, check components
4404
4405 elsif Is_Record_Type (Typ) then
4406 declare
4407 E : Entity_Id;
4408
4409 begin
4410 E := First_Entity (Typ);
4411 while Present (E) loop
4412 if Ekind (E) = E_Component
4413 or else Ekind (E) = E_Discriminant
4414 then
4415 if Component_May_Be_Bit_Aligned (E)
4416 or else
4417 Type_May_Have_Bit_Aligned_Components (Etype (E))
4418 then
4419 return True;
4420 end if;
4421 end if;
4422
4423 Next_Entity (E);
4424 end loop;
4425
4426 return False;
4427 end;
4428
4429 -- Type other than array or record is always OK
4430
4431 else
4432 return False;
4433 end if;
4434 end Type_May_Have_Bit_Aligned_Components;
4435
4436 ----------------------------
4437 -- Wrap_Cleanup_Procedure --
4438 ----------------------------
4439
4440 procedure Wrap_Cleanup_Procedure (N : Node_Id) is
4441 Loc : constant Source_Ptr := Sloc (N);
4442 Stseq : constant Node_Id := Handled_Statement_Sequence (N);
4443 Stmts : constant List_Id := Statements (Stseq);
4444
4445 begin
4446 if Abort_Allowed then
4447 Prepend_To (Stmts, Build_Runtime_Call (Loc, RE_Abort_Defer));
4448 Append_To (Stmts, Build_Runtime_Call (Loc, RE_Abort_Undefer));
4449 end if;
4450 end Wrap_Cleanup_Procedure;
4451
4452 end Exp_Util;
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