1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree; use Atree;
28 with Checks; use Checks;
29 with Einfo; use Einfo;
30 with Exp_Aggr; use Exp_Aggr;
31 with Exp_Ch7; use Exp_Ch7;
32 with Exp_Ch11; use Exp_Ch11;
33 with Exp_Dbug; use Exp_Dbug;
34 with Exp_Pakd; use Exp_Pakd;
35 with Exp_Tss; use Exp_Tss;
36 with Exp_Util; use Exp_Util;
37 with Hostparm; use Hostparm;
38 with Nlists; use Nlists;
39 with Nmake; use Nmake;
41 with Restrict; use Restrict;
42 with Rident; use Rident;
43 with Rtsfind; use Rtsfind;
44 with Sinfo; use Sinfo;
46 with Sem_Ch8; use Sem_Ch8;
47 with Sem_Ch13; use Sem_Ch13;
48 with Sem_Eval; use Sem_Eval;
49 with Sem_Res; use Sem_Res;
50 with Sem_Util; use Sem_Util;
51 with Snames; use Snames;
52 with Stand; use Stand;
53 with Stringt; use Stringt;
54 with Tbuild; use Tbuild;
55 with Ttypes; use Ttypes;
56 with Uintp; use Uintp;
57 with Validsw; use Validsw;
59 package body Exp_Ch5 is
61 function Change_Of_Representation (N : Node_Id) return Boolean;
62 -- Determine if the right hand side of the assignment N is a type
63 -- conversion which requires a change of representation. Called
64 -- only for the array and record cases.
66 procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id);
67 -- N is an assignment which assigns an array value. This routine process
68 -- the various special cases and checks required for such assignments,
69 -- including change of representation. Rhs is normally simply the right
70 -- hand side of the assignment, except that if the right hand side is
71 -- a type conversion or a qualified expression, then the Rhs is the
72 -- actual expression inside any such type conversions or qualifications.
74 function Expand_Assign_Array_Loop
81 Rev : Boolean) return Node_Id;
82 -- N is an assignment statement which assigns an array value. This routine
83 -- expands the assignment into a loop (or nested loops for the case of a
84 -- multi-dimensional array) to do the assignment component by component.
85 -- Larray and Rarray are the entities of the actual arrays on the left
86 -- hand and right hand sides. L_Type and R_Type are the types of these
87 -- arrays (which may not be the same, due to either sliding, or to a
88 -- change of representation case). Ndim is the number of dimensions and
89 -- the parameter Rev indicates if the loops run normally (Rev = False),
90 -- or reversed (Rev = True). The value returned is the constructed
91 -- loop statement. Auxiliary declarations are inserted before node N
92 -- using the standard Insert_Actions mechanism.
94 procedure Expand_Assign_Record (N : Node_Id);
95 -- N is an assignment of a non-tagged record value. This routine handles
96 -- the case where the assignment must be made component by component,
97 -- either because the target is not byte aligned, or there is a change
100 function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id;
101 -- Generate the necessary code for controlled and Tagged assignment,
102 -- that is to say, finalization of the target before, adjustement of
103 -- the target after and save and restore of the tag and finalization
104 -- pointers which are not 'part of the value' and must not be changed
105 -- upon assignment. N is the original Assignment node.
107 function Possible_Bit_Aligned_Component (N : Node_Id) return Boolean;
108 -- This function is used in processing the assignment of a record or
109 -- indexed component. The argument N is either the left hand or right
110 -- hand side of an assignment, and this function determines if there
111 -- is a record component reference where the record may be bit aligned
112 -- in a manner that causes trouble for the back end (see description
113 -- of Sem_Util.Component_May_Be_Bit_Aligned for further details).
115 ------------------------------
116 -- Change_Of_Representation --
117 ------------------------------
119 function Change_Of_Representation (N : Node_Id) return Boolean is
120 Rhs : constant Node_Id := Expression (N);
123 Nkind (Rhs) = N_Type_Conversion
125 not Same_Representation (Etype (Rhs), Etype (Expression (Rhs)));
126 end Change_Of_Representation;
128 -------------------------
129 -- Expand_Assign_Array --
130 -------------------------
132 -- There are two issues here. First, do we let Gigi do a block move, or
133 -- do we expand out into a loop? Second, we need to set the two flags
134 -- Forwards_OK and Backwards_OK which show whether the block move (or
135 -- corresponding loops) can be legitimately done in a forwards (low to
136 -- high) or backwards (high to low) manner.
138 procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id) is
139 Loc : constant Source_Ptr := Sloc (N);
141 Lhs : constant Node_Id := Name (N);
143 Act_Lhs : constant Node_Id := Get_Referenced_Object (Lhs);
144 Act_Rhs : Node_Id := Get_Referenced_Object (Rhs);
146 L_Type : constant Entity_Id :=
147 Underlying_Type (Get_Actual_Subtype (Act_Lhs));
148 R_Type : Entity_Id :=
149 Underlying_Type (Get_Actual_Subtype (Act_Rhs));
151 L_Slice : constant Boolean := Nkind (Act_Lhs) = N_Slice;
152 R_Slice : constant Boolean := Nkind (Act_Rhs) = N_Slice;
154 Crep : constant Boolean := Change_Of_Representation (N);
159 Ndim : constant Pos := Number_Dimensions (L_Type);
161 Loop_Required : Boolean := False;
162 -- This switch is set to True if the array move must be done using
163 -- an explicit front end generated loop.
165 procedure Apply_Dereference (Arg : in out Node_Id);
166 -- If the argument is an access to an array, and the assignment is
167 -- converted into a procedure call, apply explicit dereference.
169 function Has_Address_Clause (Exp : Node_Id) return Boolean;
170 -- Test if Exp is a reference to an array whose declaration has
171 -- an address clause, or it is a slice of such an array.
173 function Is_Formal_Array (Exp : Node_Id) return Boolean;
174 -- Test if Exp is a reference to an array which is either a formal
175 -- parameter or a slice of a formal parameter. These are the cases
176 -- where hidden aliasing can occur.
178 function Is_Non_Local_Array (Exp : Node_Id) return Boolean;
179 -- Determine if Exp is a reference to an array variable which is other
180 -- than an object defined in the current scope, or a slice of such
181 -- an object. Such objects can be aliased to parameters (unlike local
182 -- array references).
184 function Possible_Unaligned_Slice (Arg : Node_Id) return Boolean;
185 -- Returns True if Arg (either the left or right hand side of the
186 -- assignment) is a slice that could be unaligned wrt the array type.
187 -- This is true if Arg is a component of a packed record, or is
188 -- a record component to which a component clause applies. This
189 -- is a little pessimistic, but the result of an unnecessary
190 -- decision that something is possibly unaligned is only to
191 -- generate a front end loop, which is not so terrible.
192 -- It would really be better if backend handled this ???
194 -----------------------
195 -- Apply_Dereference --
196 -----------------------
198 procedure Apply_Dereference (Arg : in out Node_Id) is
199 Typ : constant Entity_Id := Etype (Arg);
201 if Is_Access_Type (Typ) then
202 Rewrite (Arg, Make_Explicit_Dereference (Loc,
203 Prefix => Relocate_Node (Arg)));
204 Analyze_And_Resolve (Arg, Designated_Type (Typ));
206 end Apply_Dereference;
208 ------------------------
209 -- Has_Address_Clause --
210 ------------------------
212 function Has_Address_Clause (Exp : Node_Id) return Boolean is
215 (Is_Entity_Name (Exp) and then
216 Present (Address_Clause (Entity (Exp))))
218 (Nkind (Exp) = N_Slice and then Has_Address_Clause (Prefix (Exp)));
219 end Has_Address_Clause;
221 ---------------------
222 -- Is_Formal_Array --
223 ---------------------
225 function Is_Formal_Array (Exp : Node_Id) return Boolean is
228 (Is_Entity_Name (Exp) and then Is_Formal (Entity (Exp)))
230 (Nkind (Exp) = N_Slice and then Is_Formal_Array (Prefix (Exp)));
233 ------------------------
234 -- Is_Non_Local_Array --
235 ------------------------
237 function Is_Non_Local_Array (Exp : Node_Id) return Boolean is
239 return (Is_Entity_Name (Exp)
240 and then Scope (Entity (Exp)) /= Current_Scope)
241 or else (Nkind (Exp) = N_Slice
242 and then Is_Non_Local_Array (Prefix (Exp)));
243 end Is_Non_Local_Array;
245 ------------------------------
246 -- Possible_Unaligned_Slice --
247 ------------------------------
249 function Possible_Unaligned_Slice (Arg : Node_Id) return Boolean is
251 -- No issue if this is not a slice, or else strict alignment
252 -- is not required in any case.
254 if Nkind (Arg) /= N_Slice
255 or else not Target_Strict_Alignment
260 -- No issue if the component type is a byte or byte aligned
263 Array_Typ : constant Entity_Id := Etype (Arg);
264 Comp_Typ : constant Entity_Id := Component_Type (Array_Typ);
265 Pref : constant Node_Id := Prefix (Arg);
268 if Known_Alignment (Array_Typ) then
269 if Alignment (Array_Typ) = 1 then
273 elsif Known_Component_Size (Array_Typ) then
274 if Component_Size (Array_Typ) = 1 then
278 elsif Known_Esize (Comp_Typ) then
279 if Esize (Comp_Typ) <= System_Storage_Unit then
284 -- No issue if this is not a selected component
286 if Nkind (Pref) /= N_Selected_Component then
290 -- Else we test for a possibly unaligned component
293 Is_Packed (Etype (Pref))
295 Present (Component_Clause (Entity (Selector_Name (Pref))));
297 end Possible_Unaligned_Slice;
299 -- Determine if Lhs, Rhs are formal arrays or nonlocal arrays
301 Lhs_Formal : constant Boolean := Is_Formal_Array (Act_Lhs);
302 Rhs_Formal : constant Boolean := Is_Formal_Array (Act_Rhs);
304 Lhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Lhs);
305 Rhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Rhs);
307 -- Start of processing for Expand_Assign_Array
310 -- Deal with length check, note that the length check is done with
311 -- respect to the right hand side as given, not a possible underlying
312 -- renamed object, since this would generate incorrect extra checks.
314 Apply_Length_Check (Rhs, L_Type);
316 -- We start by assuming that the move can be done in either
317 -- direction, i.e. that the two sides are completely disjoint.
319 Set_Forwards_OK (N, True);
320 Set_Backwards_OK (N, True);
322 -- Normally it is only the slice case that can lead to overlap,
323 -- and explicit checks for slices are made below. But there is
324 -- one case where the slice can be implicit and invisible to us
325 -- and that is the case where we have a one dimensional array,
326 -- and either both operands are parameters, or one is a parameter
327 -- and the other is a global variable. In this case the parameter
328 -- could be a slice that overlaps with the other parameter.
330 -- Check for the case of slices requiring an explicit loop. Normally
331 -- it is only the explicit slice cases that bother us, but in the
332 -- case of one dimensional arrays, parameters can be slices that
333 -- are passed by reference, so we can have aliasing for assignments
334 -- from one parameter to another, or assignments between parameters
335 -- and nonlocal variables. However, if the array subtype is a
336 -- constrained first subtype in the parameter case, then we don't
337 -- have to worry about overlap, since slice assignments aren't
338 -- possible (other than for a slice denoting the whole array).
340 -- Note: overlap is never possible if there is a change of
341 -- representation, so we can exclude this case.
346 ((Lhs_Formal and Rhs_Formal)
348 (Lhs_Formal and Rhs_Non_Local_Var)
350 (Rhs_Formal and Lhs_Non_Local_Var))
352 (not Is_Constrained (Etype (Lhs))
353 or else not Is_First_Subtype (Etype (Lhs)))
355 -- In the case of compiling for the Java Virtual Machine,
356 -- slices are always passed by making a copy, so we don't
357 -- have to worry about overlap. We also want to prevent
358 -- generation of "<" comparisons for array addresses,
359 -- since that's a meaningless operation on the JVM.
363 Set_Forwards_OK (N, False);
364 Set_Backwards_OK (N, False);
366 -- Note: the bit-packed case is not worrisome here, since if
367 -- we have a slice passed as a parameter, it is always aligned
368 -- on a byte boundary, and if there are no explicit slices, the
369 -- assignment can be performed directly.
372 -- We certainly must use a loop for change of representation
373 -- and also we use the operand of the conversion on the right
374 -- hand side as the effective right hand side (the component
375 -- types must match in this situation).
378 Act_Rhs := Get_Referenced_Object (Rhs);
379 R_Type := Get_Actual_Subtype (Act_Rhs);
380 Loop_Required := True;
382 -- We require a loop if the left side is possibly bit unaligned
384 elsif Possible_Bit_Aligned_Component (Lhs)
386 Possible_Bit_Aligned_Component (Rhs)
388 Loop_Required := True;
390 -- Arrays with controlled components are expanded into a loop
391 -- to force calls to adjust at the component level.
393 elsif Has_Controlled_Component (L_Type) then
394 Loop_Required := True;
396 -- Case where no slice is involved
398 elsif not L_Slice and not R_Slice then
400 -- The following code deals with the case of unconstrained bit
401 -- packed arrays. The problem is that the template for such
402 -- arrays contains the bounds of the actual source level array,
404 -- But the copy of an entire array requires the bounds of the
405 -- underlying array. It would be nice if the back end could take
406 -- care of this, but right now it does not know how, so if we
407 -- have such a type, then we expand out into a loop, which is
408 -- inefficient but works correctly. If we don't do this, we
409 -- get the wrong length computed for the array to be moved.
410 -- The two cases we need to worry about are:
412 -- Explicit deference of an unconstrained packed array type as
413 -- in the following example:
416 -- type BITS is array(INTEGER range <>) of BOOLEAN;
417 -- pragma PACK(BITS);
418 -- type A is access BITS;
421 -- P1 := new BITS (1 .. 65_535);
422 -- P2 := new BITS (1 .. 65_535);
426 -- A formal parameter reference with an unconstrained bit
427 -- array type is the other case we need to worry about (here
428 -- we assume the same BITS type declared above:
430 -- procedure Write_All (File : out BITS; Contents : in BITS);
432 -- File.Storage := Contents;
435 -- We expand to a loop in either of these two cases.
437 -- Question for future thought. Another potentially more efficient
438 -- approach would be to create the actual subtype, and then do an
439 -- unchecked conversion to this actual subtype ???
441 Check_Unconstrained_Bit_Packed_Array : declare
443 function Is_UBPA_Reference (Opnd : Node_Id) return Boolean;
444 -- Function to perform required test for the first case,
445 -- above (dereference of an unconstrained bit packed array)
447 -----------------------
448 -- Is_UBPA_Reference --
449 -----------------------
451 function Is_UBPA_Reference (Opnd : Node_Id) return Boolean is
452 Typ : constant Entity_Id := Underlying_Type (Etype (Opnd));
454 Des_Type : Entity_Id;
457 if Present (Packed_Array_Type (Typ))
458 and then Is_Array_Type (Packed_Array_Type (Typ))
459 and then not Is_Constrained (Packed_Array_Type (Typ))
463 elsif Nkind (Opnd) = N_Explicit_Dereference then
464 P_Type := Underlying_Type (Etype (Prefix (Opnd)));
466 if not Is_Access_Type (P_Type) then
470 Des_Type := Designated_Type (P_Type);
472 Is_Bit_Packed_Array (Des_Type)
473 and then not Is_Constrained (Des_Type);
479 end Is_UBPA_Reference;
481 -- Start of processing for Check_Unconstrained_Bit_Packed_Array
484 if Is_UBPA_Reference (Lhs)
486 Is_UBPA_Reference (Rhs)
488 Loop_Required := True;
490 -- Here if we do not have the case of a reference to a bit
491 -- packed unconstrained array case. In this case gigi can
492 -- most certainly handle the assignment if a forwards move
495 -- (could it handle the backwards case also???)
497 elsif Forwards_OK (N) then
500 end Check_Unconstrained_Bit_Packed_Array;
502 -- Gigi can always handle the assignment if the right side is a string
503 -- literal (note that overlap is definitely impossible in this case).
504 -- If the type is packed, a string literal is always converted into a
505 -- aggregate, except in the case of a null slice, for which no aggregate
506 -- can be written. In that case, rewrite the assignment as a null
507 -- statement, a length check has already been emitted to verify that
508 -- the range of the left-hand side is empty.
510 -- Note that this code is not executed if we had an assignment of
511 -- a string literal to a non-bit aligned component of a record, a
512 -- case which cannot be handled by the backend
514 elsif Nkind (Rhs) = N_String_Literal then
515 if String_Length (Strval (Rhs)) = 0
516 and then Is_Bit_Packed_Array (L_Type)
518 Rewrite (N, Make_Null_Statement (Loc));
524 -- If either operand is bit packed, then we need a loop, since we
525 -- can't be sure that the slice is byte aligned. Similarly, if either
526 -- operand is a possibly unaligned slice, then we need a loop (since
527 -- gigi cannot handle unaligned slices).
529 elsif Is_Bit_Packed_Array (L_Type)
530 or else Is_Bit_Packed_Array (R_Type)
531 or else Possible_Unaligned_Slice (Lhs)
532 or else Possible_Unaligned_Slice (Rhs)
534 Loop_Required := True;
536 -- If we are not bit-packed, and we have only one slice, then no
537 -- overlap is possible except in the parameter case, so we can let
538 -- gigi handle things.
540 elsif not (L_Slice and R_Slice) then
541 if Forwards_OK (N) then
546 -- Come here to compelete the analysis
548 -- Loop_Required: Set to True if we know that a loop is required
549 -- regardless of overlap considerations.
551 -- Forwards_OK: Set to False if we already know that a forwards
552 -- move is not safe, else set to True.
554 -- Backwards_OK: Set to False if we already know that a backwards
555 -- move is not safe, else set to True
557 -- Our task at this stage is to complete the overlap analysis, which
558 -- can result in possibly setting Forwards_OK or Backwards_OK to
559 -- False, and then generating the final code, either by deciding
560 -- that it is OK after all to let Gigi handle it, or by generating
561 -- appropriate code in the front end.
564 L_Index_Typ : constant Node_Id := Etype (First_Index (L_Type));
565 R_Index_Typ : constant Node_Id := Etype (First_Index (R_Type));
567 Left_Lo : constant Node_Id := Type_Low_Bound (L_Index_Typ);
568 Left_Hi : constant Node_Id := Type_High_Bound (L_Index_Typ);
569 Right_Lo : constant Node_Id := Type_Low_Bound (R_Index_Typ);
570 Right_Hi : constant Node_Id := Type_High_Bound (R_Index_Typ);
572 Act_L_Array : Node_Id;
573 Act_R_Array : Node_Id;
579 Cresult : Compare_Result;
582 -- Get the expressions for the arrays. If we are dealing with a
583 -- private type, then convert to the underlying type. We can do
584 -- direct assignments to an array that is a private type, but
585 -- we cannot assign to elements of the array without this extra
586 -- unchecked conversion.
588 if Nkind (Act_Lhs) = N_Slice then
589 Larray := Prefix (Act_Lhs);
593 if Is_Private_Type (Etype (Larray)) then
596 (Underlying_Type (Etype (Larray)), Larray);
600 if Nkind (Act_Rhs) = N_Slice then
601 Rarray := Prefix (Act_Rhs);
605 if Is_Private_Type (Etype (Rarray)) then
608 (Underlying_Type (Etype (Rarray)), Rarray);
612 -- If both sides are slices, we must figure out whether
613 -- it is safe to do the move in one direction or the other
614 -- It is always safe if there is a change of representation
615 -- since obviously two arrays with different representations
616 -- cannot possibly overlap.
618 if (not Crep) and L_Slice and R_Slice then
619 Act_L_Array := Get_Referenced_Object (Prefix (Act_Lhs));
620 Act_R_Array := Get_Referenced_Object (Prefix (Act_Rhs));
622 -- If both left and right hand arrays are entity names, and
623 -- refer to different entities, then we know that the move
624 -- is safe (the two storage areas are completely disjoint).
626 if Is_Entity_Name (Act_L_Array)
627 and then Is_Entity_Name (Act_R_Array)
628 and then Entity (Act_L_Array) /= Entity (Act_R_Array)
632 -- Otherwise, we assume the worst, which is that the two
633 -- arrays are the same array. There is no need to check if
634 -- we know that is the case, because if we don't know it,
635 -- we still have to assume it!
637 -- Generally if the same array is involved, then we have
638 -- an overlapping case. We will have to really assume the
639 -- worst (i.e. set neither of the OK flags) unless we can
640 -- determine the lower or upper bounds at compile time and
644 Cresult := Compile_Time_Compare (Left_Lo, Right_Lo);
646 if Cresult = Unknown then
647 Cresult := Compile_Time_Compare (Left_Hi, Right_Hi);
651 when LT | LE | EQ => Set_Backwards_OK (N, False);
652 when GT | GE => Set_Forwards_OK (N, False);
653 when NE | Unknown => Set_Backwards_OK (N, False);
654 Set_Forwards_OK (N, False);
659 -- If after that analysis, Forwards_OK is still True, and
660 -- Loop_Required is False, meaning that we have not discovered
661 -- some non-overlap reason for requiring a loop, then we can
662 -- still let gigi handle it.
664 if not Loop_Required then
665 if Forwards_OK (N) then
670 -- Here is where a memmove would be appropriate ???
674 -- At this stage we have to generate an explicit loop, and
675 -- we have the following cases:
677 -- Forwards_OK = True
679 -- Rnn : right_index := right_index'First;
680 -- for Lnn in left-index loop
681 -- left (Lnn) := right (Rnn);
682 -- Rnn := right_index'Succ (Rnn);
685 -- Note: the above code MUST be analyzed with checks off,
686 -- because otherwise the Succ could overflow. But in any
687 -- case this is more efficient!
689 -- Forwards_OK = False, Backwards_OK = True
691 -- Rnn : right_index := right_index'Last;
692 -- for Lnn in reverse left-index loop
693 -- left (Lnn) := right (Rnn);
694 -- Rnn := right_index'Pred (Rnn);
697 -- Note: the above code MUST be analyzed with checks off,
698 -- because otherwise the Pred could overflow. But in any
699 -- case this is more efficient!
701 -- Forwards_OK = Backwards_OK = False
703 -- This only happens if we have the same array on each side. It is
704 -- possible to create situations using overlays that violate this,
705 -- but we simply do not promise to get this "right" in this case.
707 -- There are two possible subcases. If the No_Implicit_Conditionals
708 -- restriction is set, then we generate the following code:
711 -- T : constant <operand-type> := rhs;
716 -- If implicit conditionals are permitted, then we generate:
718 -- if Left_Lo <= Right_Lo then
719 -- <code for Forwards_OK = True above>
721 -- <code for Backwards_OK = True above>
724 -- Cases where either Forwards_OK or Backwards_OK is true
726 if Forwards_OK (N) or else Backwards_OK (N) then
727 if Controlled_Type (Component_Type (L_Type))
728 and then Base_Type (L_Type) = Base_Type (R_Type)
730 and then not No_Ctrl_Actions (N)
733 Proc : constant Entity_Id :=
734 TSS (Base_Type (L_Type), TSS_Slice_Assign);
738 Apply_Dereference (Larray);
739 Apply_Dereference (Rarray);
740 Actuals := New_List (
741 Duplicate_Subexpr (Larray, Name_Req => True),
742 Duplicate_Subexpr (Rarray, Name_Req => True),
743 Duplicate_Subexpr (Left_Lo, Name_Req => True),
744 Duplicate_Subexpr (Left_Hi, Name_Req => True),
745 Duplicate_Subexpr (Right_Lo, Name_Req => True),
746 Duplicate_Subexpr (Right_Hi, Name_Req => True));
748 if Forwards_OK (N) then
750 New_Occurrence_Of (Standard_False, Loc));
753 New_Occurrence_Of (Standard_True, Loc));
757 Make_Procedure_Call_Statement (Loc,
758 Name => New_Reference_To (Proc, Loc),
759 Parameter_Associations => Actuals));
764 Expand_Assign_Array_Loop
765 (N, Larray, Rarray, L_Type, R_Type, Ndim,
766 Rev => not Forwards_OK (N)));
769 -- Case of both are false with No_Implicit_Conditionals
771 elsif Restriction_Active (No_Implicit_Conditionals) then
773 T : constant Entity_Id :=
774 Make_Defining_Identifier (Loc, Chars => Name_T);
778 Make_Block_Statement (Loc,
779 Declarations => New_List (
780 Make_Object_Declaration (Loc,
781 Defining_Identifier => T,
782 Constant_Present => True,
784 New_Occurrence_Of (Etype (Rhs), Loc),
785 Expression => Relocate_Node (Rhs))),
787 Handled_Statement_Sequence =>
788 Make_Handled_Sequence_Of_Statements (Loc,
789 Statements => New_List (
790 Make_Assignment_Statement (Loc,
791 Name => Relocate_Node (Lhs),
792 Expression => New_Occurrence_Of (T, Loc))))));
795 -- Case of both are false with implicit conditionals allowed
798 -- Before we generate this code, we must ensure that the
799 -- left and right side array types are defined. They may
800 -- be itypes, and we cannot let them be defined inside the
801 -- if, since the first use in the then may not be executed.
803 Ensure_Defined (L_Type, N);
804 Ensure_Defined (R_Type, N);
806 -- We normally compare addresses to find out which way round
807 -- to do the loop, since this is realiable, and handles the
808 -- cases of parameters, conversions etc. But we can't do that
809 -- in the bit packed case or the Java VM case, because addresses
812 if not Is_Bit_Packed_Array (L_Type) and then not Java_VM then
816 Unchecked_Convert_To (RTE (RE_Integer_Address),
817 Make_Attribute_Reference (Loc,
819 Make_Indexed_Component (Loc,
821 Duplicate_Subexpr_Move_Checks (Larray, True),
822 Expressions => New_List (
823 Make_Attribute_Reference (Loc,
827 Attribute_Name => Name_First))),
828 Attribute_Name => Name_Address)),
831 Unchecked_Convert_To (RTE (RE_Integer_Address),
832 Make_Attribute_Reference (Loc,
834 Make_Indexed_Component (Loc,
836 Duplicate_Subexpr_Move_Checks (Rarray, True),
837 Expressions => New_List (
838 Make_Attribute_Reference (Loc,
842 Attribute_Name => Name_First))),
843 Attribute_Name => Name_Address)));
845 -- For the bit packed and Java VM cases we use the bounds.
846 -- That's OK, because we don't have to worry about parameters,
847 -- since they cannot cause overlap. Perhaps we should worry
848 -- about weird slice conversions ???
851 -- Copy the bounds and reset the Analyzed flag, because the
852 -- bounds of the index type itself may be universal, and must
853 -- must be reaanalyzed to acquire the proper type for Gigi.
855 Cleft_Lo := New_Copy_Tree (Left_Lo);
856 Cright_Lo := New_Copy_Tree (Right_Lo);
857 Set_Analyzed (Cleft_Lo, False);
858 Set_Analyzed (Cright_Lo, False);
862 Left_Opnd => Cleft_Lo,
863 Right_Opnd => Cright_Lo);
866 if Controlled_Type (Component_Type (L_Type))
867 and then Base_Type (L_Type) = Base_Type (R_Type)
869 and then not No_Ctrl_Actions (N)
872 -- Call TSS procedure for array assignment, passing the
873 -- the explicit bounds of right- and left-hand side.
876 Proc : constant Node_Id :=
877 TSS (Base_Type (L_Type), TSS_Slice_Assign);
881 Apply_Dereference (Larray);
882 Apply_Dereference (Rarray);
883 Actuals := New_List (
884 Duplicate_Subexpr (Larray, Name_Req => True),
885 Duplicate_Subexpr (Rarray, Name_Req => True),
886 Duplicate_Subexpr (Left_Lo, Name_Req => True),
887 Duplicate_Subexpr (Left_Hi, Name_Req => True),
888 Duplicate_Subexpr (Right_Lo, Name_Req => True),
889 Duplicate_Subexpr (Right_Hi, Name_Req => True));
890 Append_To (Actuals, Condition);
893 Make_Procedure_Call_Statement (Loc,
894 Name => New_Reference_To (Proc, Loc),
895 Parameter_Associations => Actuals));
900 Make_Implicit_If_Statement (N,
901 Condition => Condition,
903 Then_Statements => New_List (
904 Expand_Assign_Array_Loop
905 (N, Larray, Rarray, L_Type, R_Type, Ndim,
908 Else_Statements => New_List (
909 Expand_Assign_Array_Loop
910 (N, Larray, Rarray, L_Type, R_Type, Ndim,
915 Analyze (N, Suppress => All_Checks);
919 when RE_Not_Available =>
921 end Expand_Assign_Array;
923 ------------------------------
924 -- Expand_Assign_Array_Loop --
925 ------------------------------
927 -- The following is an example of the loop generated for the case of
928 -- a two-dimensional array:
933 -- for L1b in 1 .. 100 loop
937 -- for L3b in 1 .. 100 loop
938 -- vm1 (L1b, L3b) := vm2 (R2b, R4b);
939 -- R4b := Tm1X2'succ(R4b);
942 -- R2b := Tm1X1'succ(R2b);
946 -- Here Rev is False, and Tm1Xn are the subscript types for the right
947 -- hand side. The declarations of R2b and R4b are inserted before the
948 -- original assignment statement.
950 function Expand_Assign_Array_Loop
957 Rev : Boolean) return Node_Id
959 Loc : constant Source_Ptr := Sloc (N);
961 Lnn : array (1 .. Ndim) of Entity_Id;
962 Rnn : array (1 .. Ndim) of Entity_Id;
963 -- Entities used as subscripts on left and right sides
965 L_Index_Type : array (1 .. Ndim) of Entity_Id;
966 R_Index_Type : array (1 .. Ndim) of Entity_Id;
967 -- Left and right index types
979 F_Or_L := Name_First;
983 -- Setup index types and subscript entities
990 L_Index := First_Index (L_Type);
991 R_Index := First_Index (R_Type);
993 for J in 1 .. Ndim loop
995 Make_Defining_Identifier (Loc,
996 Chars => New_Internal_Name ('L'));
999 Make_Defining_Identifier (Loc,
1000 Chars => New_Internal_Name ('R'));
1002 L_Index_Type (J) := Etype (L_Index);
1003 R_Index_Type (J) := Etype (R_Index);
1005 Next_Index (L_Index);
1006 Next_Index (R_Index);
1010 -- Now construct the assignment statement
1013 ExprL : constant List_Id := New_List;
1014 ExprR : constant List_Id := New_List;
1017 for J in 1 .. Ndim loop
1018 Append_To (ExprL, New_Occurrence_Of (Lnn (J), Loc));
1019 Append_To (ExprR, New_Occurrence_Of (Rnn (J), Loc));
1023 Make_Assignment_Statement (Loc,
1025 Make_Indexed_Component (Loc,
1026 Prefix => Duplicate_Subexpr (Larray, Name_Req => True),
1027 Expressions => ExprL),
1029 Make_Indexed_Component (Loc,
1030 Prefix => Duplicate_Subexpr (Rarray, Name_Req => True),
1031 Expressions => ExprR));
1033 -- Propagate the No_Ctrl_Actions flag to individual assignments
1035 Set_No_Ctrl_Actions (Assign, No_Ctrl_Actions (N));
1038 -- Now construct the loop from the inside out, with the last subscript
1039 -- varying most rapidly. Note that Assign is first the raw assignment
1040 -- statement, and then subsequently the loop that wraps it up.
1042 for J in reverse 1 .. Ndim loop
1044 Make_Block_Statement (Loc,
1045 Declarations => New_List (
1046 Make_Object_Declaration (Loc,
1047 Defining_Identifier => Rnn (J),
1048 Object_Definition =>
1049 New_Occurrence_Of (R_Index_Type (J), Loc),
1051 Make_Attribute_Reference (Loc,
1052 Prefix => New_Occurrence_Of (R_Index_Type (J), Loc),
1053 Attribute_Name => F_Or_L))),
1055 Handled_Statement_Sequence =>
1056 Make_Handled_Sequence_Of_Statements (Loc,
1057 Statements => New_List (
1058 Make_Implicit_Loop_Statement (N,
1060 Make_Iteration_Scheme (Loc,
1061 Loop_Parameter_Specification =>
1062 Make_Loop_Parameter_Specification (Loc,
1063 Defining_Identifier => Lnn (J),
1064 Reverse_Present => Rev,
1065 Discrete_Subtype_Definition =>
1066 New_Reference_To (L_Index_Type (J), Loc))),
1068 Statements => New_List (
1071 Make_Assignment_Statement (Loc,
1072 Name => New_Occurrence_Of (Rnn (J), Loc),
1074 Make_Attribute_Reference (Loc,
1076 New_Occurrence_Of (R_Index_Type (J), Loc),
1077 Attribute_Name => S_Or_P,
1078 Expressions => New_List (
1079 New_Occurrence_Of (Rnn (J), Loc)))))))));
1083 end Expand_Assign_Array_Loop;
1085 --------------------------
1086 -- Expand_Assign_Record --
1087 --------------------------
1089 -- The only processing required is in the change of representation
1090 -- case, where we must expand the assignment to a series of field
1091 -- by field assignments.
1093 procedure Expand_Assign_Record (N : Node_Id) is
1094 Lhs : constant Node_Id := Name (N);
1095 Rhs : Node_Id := Expression (N);
1098 -- If change of representation, then extract the real right hand
1099 -- side from the type conversion, and proceed with component-wise
1100 -- assignment, since the two types are not the same as far as the
1101 -- back end is concerned.
1103 if Change_Of_Representation (N) then
1104 Rhs := Expression (Rhs);
1106 -- If this may be a case of a large bit aligned component, then
1107 -- proceed with component-wise assignment, to avoid possible
1108 -- clobbering of other components sharing bits in the first or
1109 -- last byte of the component to be assigned.
1111 elsif Possible_Bit_Aligned_Component (Lhs)
1113 Possible_Bit_Aligned_Component (Rhs)
1117 -- If neither condition met, then nothing special to do, the back end
1118 -- can handle assignment of the entire component as a single entity.
1124 -- At this stage we know that we must do a component wise assignment
1127 Loc : constant Source_Ptr := Sloc (N);
1128 R_Typ : constant Entity_Id := Base_Type (Etype (Rhs));
1129 L_Typ : constant Entity_Id := Base_Type (Etype (Lhs));
1130 Decl : constant Node_Id := Declaration_Node (R_Typ);
1134 function Find_Component
1136 Comp : Entity_Id) return Entity_Id;
1137 -- Find the component with the given name in the underlying record
1138 -- declaration for Typ. We need to use the actual entity because
1139 -- the type may be private and resolution by identifier alone would
1142 function Make_Component_List_Assign (CL : Node_Id) return List_Id;
1143 -- Returns a sequence of statements to assign the components that
1144 -- are referenced in the given component list.
1146 function Make_Field_Assign (C : Entity_Id) return Node_Id;
1147 -- Given C, the entity for a discriminant or component, build
1148 -- an assignment for the corresponding field values.
1150 function Make_Field_Assigns (CI : List_Id) return List_Id;
1151 -- Given CI, a component items list, construct series of statements
1152 -- for fieldwise assignment of the corresponding components.
1154 --------------------
1155 -- Find_Component --
1156 --------------------
1158 function Find_Component
1160 Comp : Entity_Id) return Entity_Id
1162 Utyp : constant Entity_Id := Underlying_Type (Typ);
1166 C := First_Entity (Utyp);
1168 while Present (C) loop
1169 if Chars (C) = Chars (Comp) then
1175 raise Program_Error;
1178 --------------------------------
1179 -- Make_Component_List_Assign --
1180 --------------------------------
1182 function Make_Component_List_Assign (CL : Node_Id) return List_Id is
1183 CI : constant List_Id := Component_Items (CL);
1184 VP : constant Node_Id := Variant_Part (CL);
1193 Result := Make_Field_Assigns (CI);
1195 if Present (VP) then
1197 V := First_Non_Pragma (Variants (VP));
1199 while Present (V) loop
1202 DC := First (Discrete_Choices (V));
1203 while Present (DC) loop
1204 Append_To (DCH, New_Copy_Tree (DC));
1209 Make_Case_Statement_Alternative (Loc,
1210 Discrete_Choices => DCH,
1212 Make_Component_List_Assign (Component_List (V))));
1213 Next_Non_Pragma (V);
1217 Make_Case_Statement (Loc,
1219 Make_Selected_Component (Loc,
1220 Prefix => Duplicate_Subexpr (Rhs),
1222 Make_Identifier (Loc, Chars (Name (VP)))),
1223 Alternatives => Alts));
1228 end Make_Component_List_Assign;
1230 -----------------------
1231 -- Make_Field_Assign --
1232 -----------------------
1234 function Make_Field_Assign (C : Entity_Id) return Node_Id is
1239 Make_Assignment_Statement (Loc,
1241 Make_Selected_Component (Loc,
1242 Prefix => Duplicate_Subexpr (Lhs),
1244 New_Occurrence_Of (Find_Component (L_Typ, C), Loc)),
1246 Make_Selected_Component (Loc,
1247 Prefix => Duplicate_Subexpr (Rhs),
1248 Selector_Name => New_Occurrence_Of (C, Loc)));
1250 -- Set Assignment_OK, so discriminants can be assigned
1252 Set_Assignment_OK (Name (A), True);
1254 end Make_Field_Assign;
1256 ------------------------
1257 -- Make_Field_Assigns --
1258 ------------------------
1260 function Make_Field_Assigns (CI : List_Id) return List_Id is
1268 while Present (Item) loop
1269 if Nkind (Item) = N_Component_Declaration then
1271 (Result, Make_Field_Assign (Defining_Identifier (Item)));
1278 end Make_Field_Assigns;
1280 -- Start of processing for Expand_Assign_Record
1283 -- Note that we use the base types for this processing. This results
1284 -- in some extra work in the constrained case, but the change of
1285 -- representation case is so unusual that it is not worth the effort.
1287 -- First copy the discriminants. This is done unconditionally. It
1288 -- is required in the unconstrained left side case, and also in the
1289 -- case where this assignment was constructed during the expansion
1290 -- of a type conversion (since initialization of discriminants is
1291 -- suppressed in this case). It is unnecessary but harmless in
1294 if Has_Discriminants (L_Typ) then
1295 F := First_Discriminant (R_Typ);
1296 while Present (F) loop
1297 Insert_Action (N, Make_Field_Assign (F));
1298 Next_Discriminant (F);
1302 -- We know the underlying type is a record, but its current view
1303 -- may be private. We must retrieve the usable record declaration.
1305 if Nkind (Decl) = N_Private_Type_Declaration
1306 and then Present (Full_View (R_Typ))
1308 RDef := Type_Definition (Declaration_Node (Full_View (R_Typ)));
1310 RDef := Type_Definition (Decl);
1313 if Nkind (RDef) = N_Record_Definition
1314 and then Present (Component_List (RDef))
1317 (N, Make_Component_List_Assign (Component_List (RDef)));
1319 Rewrite (N, Make_Null_Statement (Loc));
1323 end Expand_Assign_Record;
1325 -----------------------------------
1326 -- Expand_N_Assignment_Statement --
1327 -----------------------------------
1329 -- For array types, deal with slice assignments and setting the flags
1330 -- to indicate if it can be statically determined which direction the
1331 -- move should go in. Also deal with generating range/length checks.
1333 procedure Expand_N_Assignment_Statement (N : Node_Id) is
1334 Loc : constant Source_Ptr := Sloc (N);
1335 Lhs : constant Node_Id := Name (N);
1336 Rhs : constant Node_Id := Expression (N);
1337 Typ : constant Entity_Id := Underlying_Type (Etype (Lhs));
1341 -- First deal with generation of range check if required. For now
1342 -- we do this only for discrete types.
1344 if Do_Range_Check (Rhs)
1345 and then Is_Discrete_Type (Typ)
1347 Set_Do_Range_Check (Rhs, False);
1348 Generate_Range_Check (Rhs, Typ, CE_Range_Check_Failed);
1351 -- Check for a special case where a high level transformation is
1352 -- required. If we have either of:
1357 -- where P is a reference to a bit packed array, then we have to unwind
1358 -- the assignment. The exact meaning of being a reference to a bit
1359 -- packed array is as follows:
1361 -- An indexed component whose prefix is a bit packed array is a
1362 -- reference to a bit packed array.
1364 -- An indexed component or selected component whose prefix is a
1365 -- reference to a bit packed array is itself a reference ot a
1366 -- bit packed array.
1368 -- The required transformation is
1370 -- Tnn : prefix_type := P;
1371 -- Tnn.field := rhs;
1376 -- Tnn : prefix_type := P;
1377 -- Tnn (subscr) := rhs;
1380 -- Since P is going to be evaluated more than once, any subscripts
1381 -- in P must have their evaluation forced.
1383 if (Nkind (Lhs) = N_Indexed_Component
1385 Nkind (Lhs) = N_Selected_Component)
1386 and then Is_Ref_To_Bit_Packed_Array (Prefix (Lhs))
1389 BPAR_Expr : constant Node_Id := Relocate_Node (Prefix (Lhs));
1390 BPAR_Typ : constant Entity_Id := Etype (BPAR_Expr);
1391 Tnn : constant Entity_Id :=
1392 Make_Defining_Identifier (Loc,
1393 Chars => New_Internal_Name ('T'));
1396 -- Insert the post assignment first, because we want to copy
1397 -- the BPAR_Expr tree before it gets analyzed in the context
1398 -- of the pre assignment. Note that we do not analyze the
1399 -- post assignment yet (we cannot till we have completed the
1400 -- analysis of the pre assignment). As usual, the analysis
1401 -- of this post assignment will happen on its own when we
1402 -- "run into" it after finishing the current assignment.
1405 Make_Assignment_Statement (Loc,
1406 Name => New_Copy_Tree (BPAR_Expr),
1407 Expression => New_Occurrence_Of (Tnn, Loc)));
1409 -- At this stage BPAR_Expr is a reference to a bit packed
1410 -- array where the reference was not expanded in the original
1411 -- tree, since it was on the left side of an assignment. But
1412 -- in the pre-assignment statement (the object definition),
1413 -- BPAR_Expr will end up on the right hand side, and must be
1414 -- reexpanded. To achieve this, we reset the analyzed flag
1415 -- of all selected and indexed components down to the actual
1416 -- indexed component for the packed array.
1420 Set_Analyzed (Exp, False);
1422 if Nkind (Exp) = N_Selected_Component
1424 Nkind (Exp) = N_Indexed_Component
1426 Exp := Prefix (Exp);
1432 -- Now we can insert and analyze the pre-assignment.
1434 -- If the right-hand side requires a transient scope, it has
1435 -- already been placed on the stack. However, the declaration is
1436 -- inserted in the tree outside of this scope, and must reflect
1437 -- the proper scope for its variable. This awkward bit is forced
1438 -- by the stricter scope discipline imposed by GCC 2.97.
1441 Uses_Transient_Scope : constant Boolean :=
1442 Scope_Is_Transient and then N = Node_To_Be_Wrapped;
1445 if Uses_Transient_Scope then
1446 New_Scope (Scope (Current_Scope));
1449 Insert_Before_And_Analyze (N,
1450 Make_Object_Declaration (Loc,
1451 Defining_Identifier => Tnn,
1452 Object_Definition => New_Occurrence_Of (BPAR_Typ, Loc),
1453 Expression => BPAR_Expr));
1455 if Uses_Transient_Scope then
1460 -- Now fix up the original assignment and continue processing
1462 Rewrite (Prefix (Lhs),
1463 New_Occurrence_Of (Tnn, Loc));
1465 -- We do not need to reanalyze that assignment, and we do not need
1466 -- to worry about references to the temporary, but we do need to
1467 -- make sure that the temporary is not marked as a true constant
1468 -- since we now have a generate assignment to it!
1470 Set_Is_True_Constant (Tnn, False);
1474 -- When we have the appropriate type of aggregate in the
1475 -- expression (it has been determined during analysis of the
1476 -- aggregate by setting the delay flag), let's perform in place
1477 -- assignment and thus avoid creating a temporay.
1479 if Is_Delayed_Aggregate (Rhs) then
1480 Convert_Aggr_In_Assignment (N);
1481 Rewrite (N, Make_Null_Statement (Loc));
1486 -- Apply discriminant check if required. If Lhs is an access type
1487 -- to a designated type with discriminants, we must always check.
1489 if Has_Discriminants (Etype (Lhs)) then
1491 -- Skip discriminant check if change of representation. Will be
1492 -- done when the change of representation is expanded out.
1494 if not Change_Of_Representation (N) then
1495 Apply_Discriminant_Check (Rhs, Etype (Lhs), Lhs);
1498 -- If the type is private without discriminants, and the full type
1499 -- has discriminants (necessarily with defaults) a check may still be
1500 -- necessary if the Lhs is aliased. The private determinants must be
1501 -- visible to build the discriminant constraints.
1503 -- Only an explicit dereference that comes from source indicates
1504 -- aliasing. Access to formals of protected operations and entries
1505 -- create dereferences but are not semantic aliasings.
1507 elsif Is_Private_Type (Etype (Lhs))
1508 and then Has_Discriminants (Typ)
1509 and then Nkind (Lhs) = N_Explicit_Dereference
1510 and then Comes_From_Source (Lhs)
1513 Lt : constant Entity_Id := Etype (Lhs);
1515 Set_Etype (Lhs, Typ);
1516 Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs));
1517 Apply_Discriminant_Check (Rhs, Typ, Lhs);
1518 Set_Etype (Lhs, Lt);
1521 -- If the Lhs has a private type with unknown discriminants, it
1522 -- may have a full view with discriminants, but those are nameable
1523 -- only in the underlying type, so convert the Rhs to it before
1524 -- potential checking.
1526 elsif Has_Unknown_Discriminants (Base_Type (Etype (Lhs)))
1527 and then Has_Discriminants (Typ)
1529 Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs));
1530 Apply_Discriminant_Check (Rhs, Typ, Lhs);
1532 -- In the access type case, we need the same discriminant check,
1533 -- and also range checks if we have an access to constrained array.
1535 elsif Is_Access_Type (Etype (Lhs))
1536 and then Is_Constrained (Designated_Type (Etype (Lhs)))
1538 if Has_Discriminants (Designated_Type (Etype (Lhs))) then
1540 -- Skip discriminant check if change of representation. Will be
1541 -- done when the change of representation is expanded out.
1543 if not Change_Of_Representation (N) then
1544 Apply_Discriminant_Check (Rhs, Etype (Lhs));
1547 elsif Is_Array_Type (Designated_Type (Etype (Lhs))) then
1548 Apply_Range_Check (Rhs, Etype (Lhs));
1550 if Is_Constrained (Etype (Lhs)) then
1551 Apply_Length_Check (Rhs, Etype (Lhs));
1554 if Nkind (Rhs) = N_Allocator then
1556 Target_Typ : constant Entity_Id := Etype (Expression (Rhs));
1557 C_Es : Check_Result;
1564 Etype (Designated_Type (Etype (Lhs))));
1576 -- Apply range check for access type case
1578 elsif Is_Access_Type (Etype (Lhs))
1579 and then Nkind (Rhs) = N_Allocator
1580 and then Nkind (Expression (Rhs)) = N_Qualified_Expression
1582 Analyze_And_Resolve (Expression (Rhs));
1584 (Expression (Rhs), Designated_Type (Etype (Lhs)));
1587 -- If we are assigning an access type and the left side is an
1588 -- entity, then make sure that Is_Known_Non_Null properly
1589 -- reflects the state of the entity after the assignment
1591 if Is_Access_Type (Typ)
1592 and then Is_Entity_Name (Lhs)
1593 and then Known_Non_Null (Rhs)
1594 and then Safe_To_Capture_Value (N, Entity (Lhs))
1596 Set_Is_Known_Non_Null (Entity (Lhs), Known_Non_Null (Rhs));
1599 -- Case of assignment to a bit packed array element
1601 if Nkind (Lhs) = N_Indexed_Component
1602 and then Is_Bit_Packed_Array (Etype (Prefix (Lhs)))
1604 Expand_Bit_Packed_Element_Set (N);
1607 -- Case of tagged type assignment
1609 elsif Is_Tagged_Type (Typ)
1610 or else (Controlled_Type (Typ) and then not Is_Array_Type (Typ))
1612 Tagged_Case : declare
1613 L : List_Id := No_List;
1614 Expand_Ctrl_Actions : constant Boolean := not No_Ctrl_Actions (N);
1617 -- In the controlled case, we need to make sure that function
1618 -- calls are evaluated before finalizing the target. In all
1619 -- cases, it makes the expansion easier if the side-effects
1620 -- are removed first.
1622 Remove_Side_Effects (Lhs);
1623 Remove_Side_Effects (Rhs);
1625 -- Avoid recursion in the mechanism
1629 -- If dispatching assignment, we need to dispatch to _assign
1631 if Is_Class_Wide_Type (Typ)
1633 -- If the type is tagged, we may as well use the predefined
1634 -- primitive assignment. This avoids inlining a lot of code
1635 -- and in the class-wide case, the assignment is replaced by
1636 -- a dispatch call to _assign. Note that this cannot be done
1637 -- when discriminant checks are locally suppressed (as in
1638 -- extension aggregate expansions) because otherwise the
1639 -- discriminant check will be performed within the _assign
1642 or else (Is_Tagged_Type (Typ)
1643 and then Chars (Current_Scope) /= Name_uAssign
1644 and then Expand_Ctrl_Actions
1645 and then not Discriminant_Checks_Suppressed (Empty))
1647 -- Fetch the primitive op _assign and proper type to call
1648 -- it. Because of possible conflits between private and
1649 -- full view the proper type is fetched directly from the
1650 -- operation profile.
1653 Op : constant Entity_Id :=
1654 Find_Prim_Op (Typ, Name_uAssign);
1655 F_Typ : Entity_Id := Etype (First_Formal (Op));
1658 -- If the assignment is dispatching, make sure to use the
1659 -- ??? where is rest of this comment ???
1661 if Is_Class_Wide_Type (Typ) then
1662 F_Typ := Class_Wide_Type (F_Typ);
1666 Make_Procedure_Call_Statement (Loc,
1667 Name => New_Reference_To (Op, Loc),
1668 Parameter_Associations => New_List (
1669 Unchecked_Convert_To (F_Typ, Duplicate_Subexpr (Lhs)),
1670 Unchecked_Convert_To (F_Typ,
1671 Duplicate_Subexpr (Rhs)))));
1675 L := Make_Tag_Ctrl_Assignment (N);
1677 -- We can't afford to have destructive Finalization Actions
1678 -- in the Self assignment case, so if the target and the
1679 -- source are not obviously different, code is generated to
1680 -- avoid the self assignment case
1682 -- if lhs'address /= rhs'address then
1683 -- <code for controlled and/or tagged assignment>
1686 if not Statically_Different (Lhs, Rhs)
1687 and then Expand_Ctrl_Actions
1690 Make_Implicit_If_Statement (N,
1694 Make_Attribute_Reference (Loc,
1695 Prefix => Duplicate_Subexpr (Lhs),
1696 Attribute_Name => Name_Address),
1699 Make_Attribute_Reference (Loc,
1700 Prefix => Duplicate_Subexpr (Rhs),
1701 Attribute_Name => Name_Address)),
1703 Then_Statements => L));
1706 -- We need to set up an exception handler for implementing
1707 -- 7.6.1 (18). The remaining adjustments are tackled by the
1708 -- implementation of adjust for record_controllers (see
1711 -- This is skipped if we have no finalization
1713 if Expand_Ctrl_Actions
1714 and then not Restriction_Active (No_Finalization)
1717 Make_Block_Statement (Loc,
1718 Handled_Statement_Sequence =>
1719 Make_Handled_Sequence_Of_Statements (Loc,
1721 Exception_Handlers => New_List (
1722 Make_Exception_Handler (Loc,
1723 Exception_Choices =>
1724 New_List (Make_Others_Choice (Loc)),
1725 Statements => New_List (
1726 Make_Raise_Program_Error (Loc,
1728 PE_Finalize_Raised_Exception)
1734 Make_Block_Statement (Loc,
1735 Handled_Statement_Sequence =>
1736 Make_Handled_Sequence_Of_Statements (Loc, Statements => L)));
1738 -- If no restrictions on aborts, protect the whole assignement
1739 -- for controlled objects as per 9.8(11)
1741 if Controlled_Type (Typ)
1742 and then Expand_Ctrl_Actions
1743 and then Abort_Allowed
1746 Blk : constant Entity_Id :=
1747 New_Internal_Entity (
1748 E_Block, Current_Scope, Sloc (N), 'B');
1751 Set_Scope (Blk, Current_Scope);
1752 Set_Etype (Blk, Standard_Void_Type);
1753 Set_Identifier (N, New_Occurrence_Of (Blk, Sloc (N)));
1755 Prepend_To (L, Build_Runtime_Call (Loc, RE_Abort_Defer));
1756 Set_At_End_Proc (Handled_Statement_Sequence (N),
1757 New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc));
1758 Expand_At_End_Handler
1759 (Handled_Statement_Sequence (N), Blk);
1769 elsif Is_Array_Type (Typ) then
1771 Actual_Rhs : Node_Id := Rhs;
1774 while Nkind (Actual_Rhs) = N_Type_Conversion
1776 Nkind (Actual_Rhs) = N_Qualified_Expression
1778 Actual_Rhs := Expression (Actual_Rhs);
1781 Expand_Assign_Array (N, Actual_Rhs);
1787 elsif Is_Record_Type (Typ) then
1788 Expand_Assign_Record (N);
1791 -- Scalar types. This is where we perform the processing related
1792 -- to the requirements of (RM 13.9.1(9-11)) concerning the handling
1793 -- of invalid scalar values.
1795 elsif Is_Scalar_Type (Typ) then
1797 -- Case where right side is known valid
1799 if Expr_Known_Valid (Rhs) then
1801 -- Here the right side is valid, so it is fine. The case to
1802 -- deal with is when the left side is a local variable reference
1803 -- whose value is not currently known to be valid. If this is
1804 -- the case, and the assignment appears in an unconditional
1805 -- context, then we can mark the left side as now being valid.
1807 if Is_Local_Variable_Reference (Lhs)
1808 and then not Is_Known_Valid (Entity (Lhs))
1809 and then In_Unconditional_Context (N)
1811 Set_Is_Known_Valid (Entity (Lhs), True);
1814 -- Case where right side may be invalid in the sense of the RM
1815 -- reference above. The RM does not require that we check for
1816 -- the validity on an assignment, but it does require that the
1817 -- assignment of an invalid value not cause erroneous behavior.
1819 -- The general approach in GNAT is to use the Is_Known_Valid flag
1820 -- to avoid the need for validity checking on assignments. However
1821 -- in some cases, we have to do validity checking in order to make
1822 -- sure that the setting of this flag is correct.
1825 -- Validate right side if we are validating copies
1827 if Validity_Checks_On
1828 and then Validity_Check_Copies
1832 -- We can propagate this to the left side where appropriate
1834 if Is_Local_Variable_Reference (Lhs)
1835 and then not Is_Known_Valid (Entity (Lhs))
1836 and then In_Unconditional_Context (N)
1838 Set_Is_Known_Valid (Entity (Lhs), True);
1841 -- Otherwise check to see what should be done
1843 -- If left side is a local variable, then we just set its
1844 -- flag to indicate that its value may no longer be valid,
1845 -- since we are copying a potentially invalid value.
1847 elsif Is_Local_Variable_Reference (Lhs) then
1848 Set_Is_Known_Valid (Entity (Lhs), False);
1850 -- Check for case of a nonlocal variable on the left side
1851 -- which is currently known to be valid. In this case, we
1852 -- simply ensure that the right side is valid. We only play
1853 -- the game of copying validity status for local variables,
1854 -- since we are doing this statically, not by tracing the
1857 elsif Is_Entity_Name (Lhs)
1858 and then Is_Known_Valid (Entity (Lhs))
1860 -- Note that the Ensure_Valid call is ignored if the
1861 -- Validity_Checking mode is set to none so we do not
1862 -- need to worry about that case here.
1866 -- In all other cases, we can safely copy an invalid value
1867 -- without worrying about the status of the left side. Since
1868 -- it is not a variable reference it will not be considered
1869 -- as being known to be valid in any case.
1877 -- Defend against invalid subscripts on left side if we are in
1878 -- standard validity checking mode. No need to do this if we
1879 -- are checking all subscripts.
1881 if Validity_Checks_On
1882 and then Validity_Check_Default
1883 and then not Validity_Check_Subscripts
1885 Check_Valid_Lvalue_Subscripts (Lhs);
1889 when RE_Not_Available =>
1891 end Expand_N_Assignment_Statement;
1893 ------------------------------
1894 -- Expand_N_Block_Statement --
1895 ------------------------------
1897 -- Encode entity names defined in block statement
1899 procedure Expand_N_Block_Statement (N : Node_Id) is
1901 Qualify_Entity_Names (N);
1902 end Expand_N_Block_Statement;
1904 -----------------------------
1905 -- Expand_N_Case_Statement --
1906 -----------------------------
1908 procedure Expand_N_Case_Statement (N : Node_Id) is
1909 Loc : constant Source_Ptr := Sloc (N);
1910 Expr : constant Node_Id := Expression (N);
1918 -- Check for the situation where we know at compile time which
1919 -- branch will be taken
1921 if Compile_Time_Known_Value (Expr) then
1922 Alt := Find_Static_Alternative (N);
1924 -- Move the statements from this alternative after the case
1925 -- statement. They are already analyzed, so will be skipped
1928 Insert_List_After (N, Statements (Alt));
1930 -- That leaves the case statement as a shell. The alternative
1931 -- that will be executed is reset to a null list. So now we can
1932 -- kill the entire case statement.
1934 Kill_Dead_Code (Expression (N));
1935 Kill_Dead_Code (Alternatives (N));
1936 Rewrite (N, Make_Null_Statement (Loc));
1940 -- Here if the choice is not determined at compile time
1943 Last_Alt : constant Node_Id := Last (Alternatives (N));
1945 Others_Present : Boolean;
1946 Others_Node : Node_Id;
1948 Then_Stms : List_Id;
1949 Else_Stms : List_Id;
1952 if Nkind (First (Discrete_Choices (Last_Alt))) = N_Others_Choice then
1953 Others_Present := True;
1954 Others_Node := Last_Alt;
1956 Others_Present := False;
1959 -- First step is to worry about possible invalid argument. The RM
1960 -- requires (RM 5.4(13)) that if the result is invalid (e.g. it is
1961 -- outside the base range), then Constraint_Error must be raised.
1963 -- Case of validity check required (validity checks are on, the
1964 -- expression is not known to be valid, and the case statement
1965 -- comes from source -- no need to validity check internally
1966 -- generated case statements).
1968 if Validity_Check_Default then
1969 Ensure_Valid (Expr);
1972 -- If there is only a single alternative, just replace it with
1973 -- the sequence of statements since obviously that is what is
1974 -- going to be executed in all cases.
1976 Len := List_Length (Alternatives (N));
1979 -- We still need to evaluate the expression if it has any
1982 Remove_Side_Effects (Expression (N));
1984 Insert_List_After (N, Statements (First (Alternatives (N))));
1986 -- That leaves the case statement as a shell. The alternative
1987 -- that will be executed is reset to a null list. So now we can
1988 -- kill the entire case statement.
1990 Kill_Dead_Code (Expression (N));
1991 Rewrite (N, Make_Null_Statement (Loc));
1995 -- An optimization. If there are only two alternatives, and only
1996 -- a single choice, then rewrite the whole case statement as an
1997 -- if statement, since this can result in susbequent optimizations.
1998 -- This helps not only with case statements in the source of a
1999 -- simple form, but also with generated code (discriminant check
2000 -- functions in particular)
2003 Chlist := Discrete_Choices (First (Alternatives (N)));
2005 if List_Length (Chlist) = 1 then
2006 Choice := First (Chlist);
2008 Then_Stms := Statements (First (Alternatives (N)));
2009 Else_Stms := Statements (Last (Alternatives (N)));
2011 -- For TRUE, generate "expression", not expression = true
2013 if Nkind (Choice) = N_Identifier
2014 and then Entity (Choice) = Standard_True
2016 Cond := Expression (N);
2018 -- For FALSE, generate "expression" and switch then/else
2020 elsif Nkind (Choice) = N_Identifier
2021 and then Entity (Choice) = Standard_False
2023 Cond := Expression (N);
2024 Else_Stms := Statements (First (Alternatives (N)));
2025 Then_Stms := Statements (Last (Alternatives (N)));
2027 -- For a range, generate "expression in range"
2029 elsif Nkind (Choice) = N_Range
2030 or else (Nkind (Choice) = N_Attribute_Reference
2031 and then Attribute_Name (Choice) = Name_Range)
2032 or else (Is_Entity_Name (Choice)
2033 and then Is_Type (Entity (Choice)))
2034 or else Nkind (Choice) = N_Subtype_Indication
2038 Left_Opnd => Expression (N),
2039 Right_Opnd => Relocate_Node (Choice));
2041 -- For any other subexpression "expression = value"
2046 Left_Opnd => Expression (N),
2047 Right_Opnd => Relocate_Node (Choice));
2050 -- Now rewrite the case as an IF
2053 Make_If_Statement (Loc,
2055 Then_Statements => Then_Stms,
2056 Else_Statements => Else_Stms));
2062 -- If the last alternative is not an Others choice, replace it
2063 -- with an N_Others_Choice. Note that we do not bother to call
2064 -- Analyze on the modified case statement, since it's only effect
2065 -- would be to compute the contents of the Others_Discrete_Choices
2066 -- which is not needed by the back end anyway.
2068 -- The reason we do this is that the back end always needs some
2069 -- default for a switch, so if we have not supplied one in the
2070 -- processing above for validity checking, then we need to
2073 if not Others_Present then
2074 Others_Node := Make_Others_Choice (Sloc (Last_Alt));
2075 Set_Others_Discrete_Choices
2076 (Others_Node, Discrete_Choices (Last_Alt));
2077 Set_Discrete_Choices (Last_Alt, New_List (Others_Node));
2080 end Expand_N_Case_Statement;
2082 -----------------------------
2083 -- Expand_N_Exit_Statement --
2084 -----------------------------
2086 -- The only processing required is to deal with a possible C/Fortran
2087 -- boolean value used as the condition for the exit statement.
2089 procedure Expand_N_Exit_Statement (N : Node_Id) is
2091 Adjust_Condition (Condition (N));
2092 end Expand_N_Exit_Statement;
2094 -----------------------------
2095 -- Expand_N_Goto_Statement --
2096 -----------------------------
2098 -- Add poll before goto if polling active
2100 procedure Expand_N_Goto_Statement (N : Node_Id) is
2102 Generate_Poll_Call (N);
2103 end Expand_N_Goto_Statement;
2105 ---------------------------
2106 -- Expand_N_If_Statement --
2107 ---------------------------
2109 -- First we deal with the case of C and Fortran convention boolean
2110 -- values, with zero/non-zero semantics.
2112 -- Second, we deal with the obvious rewriting for the cases where the
2113 -- condition of the IF is known at compile time to be True or False.
2115 -- Third, we remove elsif parts which have non-empty Condition_Actions
2116 -- and rewrite as independent if statements. For example:
2127 -- <<condition actions of y>>
2133 -- This rewriting is needed if at least one elsif part has a non-empty
2134 -- Condition_Actions list. We also do the same processing if there is
2135 -- a constant condition in an elsif part (in conjunction with the first
2136 -- processing step mentioned above, for the recursive call made to deal
2137 -- with the created inner if, this deals with properly optimizing the
2138 -- cases of constant elsif conditions).
2140 procedure Expand_N_If_Statement (N : Node_Id) is
2141 Loc : constant Source_Ptr := Sloc (N);
2147 Adjust_Condition (Condition (N));
2149 -- The following loop deals with constant conditions for the IF. We
2150 -- need a loop because as we eliminate False conditions, we grab the
2151 -- first elsif condition and use it as the primary condition.
2153 while Compile_Time_Known_Value (Condition (N)) loop
2155 -- If condition is True, we can simply rewrite the if statement
2156 -- now by replacing it by the series of then statements.
2158 if Is_True (Expr_Value (Condition (N))) then
2160 -- All the else parts can be killed
2162 Kill_Dead_Code (Elsif_Parts (N));
2163 Kill_Dead_Code (Else_Statements (N));
2165 Hed := Remove_Head (Then_Statements (N));
2166 Insert_List_After (N, Then_Statements (N));
2170 -- If condition is False, then we can delete the condition and
2171 -- the Then statements
2174 -- We do not delete the condition if constant condition
2175 -- warnings are enabled, since otherwise we end up deleting
2176 -- the desired warning. Of course the backend will get rid
2177 -- of this True/False test anyway, so nothing is lost here.
2179 if not Constant_Condition_Warnings then
2180 Kill_Dead_Code (Condition (N));
2183 Kill_Dead_Code (Then_Statements (N));
2185 -- If there are no elsif statements, then we simply replace
2186 -- the entire if statement by the sequence of else statements.
2188 if No (Elsif_Parts (N)) then
2190 if No (Else_Statements (N))
2191 or else Is_Empty_List (Else_Statements (N))
2194 Make_Null_Statement (Sloc (N)));
2197 Hed := Remove_Head (Else_Statements (N));
2198 Insert_List_After (N, Else_Statements (N));
2204 -- If there are elsif statements, the first of them becomes
2205 -- the if/then section of the rebuilt if statement This is
2206 -- the case where we loop to reprocess this copied condition.
2209 Hed := Remove_Head (Elsif_Parts (N));
2210 Insert_Actions (N, Condition_Actions (Hed));
2211 Set_Condition (N, Condition (Hed));
2212 Set_Then_Statements (N, Then_Statements (Hed));
2214 if Is_Empty_List (Elsif_Parts (N)) then
2215 Set_Elsif_Parts (N, No_List);
2221 -- Loop through elsif parts, dealing with constant conditions and
2222 -- possible expression actions that are present.
2224 if Present (Elsif_Parts (N)) then
2225 E := First (Elsif_Parts (N));
2226 while Present (E) loop
2227 Adjust_Condition (Condition (E));
2229 -- If there are condition actions, then we rewrite the if
2230 -- statement as indicated above. We also do the same rewrite
2231 -- if the condition is True or False. The further processing
2232 -- of this constant condition is then done by the recursive
2233 -- call to expand the newly created if statement
2235 if Present (Condition_Actions (E))
2236 or else Compile_Time_Known_Value (Condition (E))
2238 -- Note this is not an implicit if statement, since it is
2239 -- part of an explicit if statement in the source (or of an
2240 -- implicit if statement that has already been tested).
2243 Make_If_Statement (Sloc (E),
2244 Condition => Condition (E),
2245 Then_Statements => Then_Statements (E),
2246 Elsif_Parts => No_List,
2247 Else_Statements => Else_Statements (N));
2249 -- Elsif parts for new if come from remaining elsif's of parent
2251 while Present (Next (E)) loop
2252 if No (Elsif_Parts (New_If)) then
2253 Set_Elsif_Parts (New_If, New_List);
2256 Append (Remove_Next (E), Elsif_Parts (New_If));
2259 Set_Else_Statements (N, New_List (New_If));
2261 if Present (Condition_Actions (E)) then
2262 Insert_List_Before (New_If, Condition_Actions (E));
2267 if Is_Empty_List (Elsif_Parts (N)) then
2268 Set_Elsif_Parts (N, No_List);
2274 -- No special processing for that elsif part, move to next
2282 -- Some more optimizations applicable if we still have an IF statement
2284 if Nkind (N) /= N_If_Statement then
2288 -- Another optimization, special cases that can be simplified
2290 -- if expression then
2296 -- can be changed to:
2298 -- return expression;
2302 -- if expression then
2308 -- can be changed to:
2310 -- return not (expression);
2312 if Nkind (N) = N_If_Statement
2313 and then No (Elsif_Parts (N))
2314 and then Present (Else_Statements (N))
2315 and then List_Length (Then_Statements (N)) = 1
2316 and then List_Length (Else_Statements (N)) = 1
2319 Then_Stm : constant Node_Id := First (Then_Statements (N));
2320 Else_Stm : constant Node_Id := First (Else_Statements (N));
2323 if Nkind (Then_Stm) = N_Return_Statement
2325 Nkind (Else_Stm) = N_Return_Statement
2328 Then_Expr : constant Node_Id := Expression (Then_Stm);
2329 Else_Expr : constant Node_Id := Expression (Else_Stm);
2332 if Nkind (Then_Expr) = N_Identifier
2334 Nkind (Else_Expr) = N_Identifier
2336 if Entity (Then_Expr) = Standard_True
2337 and then Entity (Else_Expr) = Standard_False
2340 Make_Return_Statement (Loc,
2341 Expression => Relocate_Node (Condition (N))));
2345 elsif Entity (Then_Expr) = Standard_False
2346 and then Entity (Else_Expr) = Standard_True
2349 Make_Return_Statement (Loc,
2352 Right_Opnd => Relocate_Node (Condition (N)))));
2361 end Expand_N_If_Statement;
2363 -----------------------------
2364 -- Expand_N_Loop_Statement --
2365 -----------------------------
2367 -- 1. Deal with while condition for C/Fortran boolean
2368 -- 2. Deal with loops with a non-standard enumeration type range
2369 -- 3. Deal with while loops where Condition_Actions is set
2370 -- 4. Insert polling call if required
2372 procedure Expand_N_Loop_Statement (N : Node_Id) is
2373 Loc : constant Source_Ptr := Sloc (N);
2374 Isc : constant Node_Id := Iteration_Scheme (N);
2377 if Present (Isc) then
2378 Adjust_Condition (Condition (Isc));
2381 if Is_Non_Empty_List (Statements (N)) then
2382 Generate_Poll_Call (First (Statements (N)));
2389 -- Handle the case where we have a for loop with the range type being
2390 -- an enumeration type with non-standard representation. In this case
2393 -- for x in [reverse] a .. b loop
2399 -- for xP in [reverse] integer
2400 -- range etype'Pos (a) .. etype'Pos (b) loop
2402 -- x : constant etype := Pos_To_Rep (xP);
2408 if Present (Loop_Parameter_Specification (Isc)) then
2410 LPS : constant Node_Id := Loop_Parameter_Specification (Isc);
2411 Loop_Id : constant Entity_Id := Defining_Identifier (LPS);
2412 Ltype : constant Entity_Id := Etype (Loop_Id);
2413 Btype : constant Entity_Id := Base_Type (Ltype);
2418 if not Is_Enumeration_Type (Btype)
2419 or else No (Enum_Pos_To_Rep (Btype))
2425 Make_Defining_Identifier (Loc,
2426 Chars => New_External_Name (Chars (Loop_Id), 'P'));
2428 -- If the type has a contiguous representation, successive
2429 -- values can be generated as offsets from the first literal.
2431 if Has_Contiguous_Rep (Btype) then
2433 Unchecked_Convert_To (Btype,
2436 Make_Integer_Literal (Loc,
2437 Enumeration_Rep (First_Literal (Btype))),
2438 Right_Opnd => New_Reference_To (New_Id, Loc)));
2440 -- Use the constructed array Enum_Pos_To_Rep.
2443 Make_Indexed_Component (Loc,
2444 Prefix => New_Reference_To (Enum_Pos_To_Rep (Btype), Loc),
2445 Expressions => New_List (New_Reference_To (New_Id, Loc)));
2449 Make_Loop_Statement (Loc,
2450 Identifier => Identifier (N),
2453 Make_Iteration_Scheme (Loc,
2454 Loop_Parameter_Specification =>
2455 Make_Loop_Parameter_Specification (Loc,
2456 Defining_Identifier => New_Id,
2457 Reverse_Present => Reverse_Present (LPS),
2459 Discrete_Subtype_Definition =>
2460 Make_Subtype_Indication (Loc,
2463 New_Reference_To (Standard_Natural, Loc),
2466 Make_Range_Constraint (Loc,
2471 Make_Attribute_Reference (Loc,
2473 New_Reference_To (Btype, Loc),
2475 Attribute_Name => Name_Pos,
2477 Expressions => New_List (
2479 (Type_Low_Bound (Ltype)))),
2482 Make_Attribute_Reference (Loc,
2484 New_Reference_To (Btype, Loc),
2486 Attribute_Name => Name_Pos,
2488 Expressions => New_List (
2490 (Type_High_Bound (Ltype))))))))),
2492 Statements => New_List (
2493 Make_Block_Statement (Loc,
2494 Declarations => New_List (
2495 Make_Object_Declaration (Loc,
2496 Defining_Identifier => Loop_Id,
2497 Constant_Present => True,
2498 Object_Definition => New_Reference_To (Ltype, Loc),
2499 Expression => Expr)),
2501 Handled_Statement_Sequence =>
2502 Make_Handled_Sequence_Of_Statements (Loc,
2503 Statements => Statements (N)))),
2505 End_Label => End_Label (N)));
2509 -- Second case, if we have a while loop with Condition_Actions set,
2510 -- then we change it into a plain loop:
2519 -- <<condition actions>>
2525 and then Present (Condition_Actions (Isc))
2532 Make_Exit_Statement (Sloc (Condition (Isc)),
2534 Make_Op_Not (Sloc (Condition (Isc)),
2535 Right_Opnd => Condition (Isc)));
2537 Prepend (ES, Statements (N));
2538 Insert_List_Before (ES, Condition_Actions (Isc));
2540 -- This is not an implicit loop, since it is generated in
2541 -- response to the loop statement being processed. If this
2542 -- is itself implicit, the restriction has already been
2543 -- checked. If not, it is an explicit loop.
2546 Make_Loop_Statement (Sloc (N),
2547 Identifier => Identifier (N),
2548 Statements => Statements (N),
2549 End_Label => End_Label (N)));
2554 end Expand_N_Loop_Statement;
2556 -------------------------------
2557 -- Expand_N_Return_Statement --
2558 -------------------------------
2560 procedure Expand_N_Return_Statement (N : Node_Id) is
2561 Loc : constant Source_Ptr := Sloc (N);
2562 Exp : constant Node_Id := Expression (N);
2566 Scope_Id : Entity_Id;
2570 Goto_Stat : Node_Id;
2573 Return_Type : Entity_Id;
2574 Result_Exp : Node_Id;
2575 Result_Id : Entity_Id;
2576 Result_Obj : Node_Id;
2579 -- Case where returned expression is present
2581 if Present (Exp) then
2583 -- Always normalize C/Fortran boolean result. This is not always
2584 -- necessary, but it seems a good idea to minimize the passing
2585 -- around of non-normalized values, and in any case this handles
2586 -- the processing of barrier functions for protected types, which
2587 -- turn the condition into a return statement.
2589 Exptyp := Etype (Exp);
2591 if Is_Boolean_Type (Exptyp)
2592 and then Nonzero_Is_True (Exptyp)
2594 Adjust_Condition (Exp);
2595 Adjust_Result_Type (Exp, Exptyp);
2598 -- Do validity check if enabled for returns
2600 if Validity_Checks_On
2601 and then Validity_Check_Returns
2607 -- Find relevant enclosing scope from which return is returning
2609 Cur_Idx := Scope_Stack.Last;
2611 Scope_Id := Scope_Stack.Table (Cur_Idx).Entity;
2613 if Ekind (Scope_Id) /= E_Block
2614 and then Ekind (Scope_Id) /= E_Loop
2619 Cur_Idx := Cur_Idx - 1;
2620 pragma Assert (Cur_Idx >= 0);
2625 Kind := Ekind (Scope_Id);
2627 -- If it is a return from procedures do no extra steps.
2629 if Kind = E_Procedure or else Kind = E_Generic_Procedure then
2633 pragma Assert (Is_Entry (Scope_Id));
2635 -- Look at the enclosing block to see whether the return is from
2636 -- an accept statement or an entry body.
2638 for J in reverse 0 .. Cur_Idx loop
2639 Scope_Id := Scope_Stack.Table (J).Entity;
2640 exit when Is_Concurrent_Type (Scope_Id);
2643 -- If it is a return from accept statement it should be expanded
2644 -- as a call to RTS Complete_Rendezvous and a goto to the end of
2647 -- (cf : Expand_N_Accept_Statement, Expand_N_Selective_Accept,
2648 -- Expand_N_Accept_Alternative in exp_ch9.adb)
2650 if Is_Task_Type (Scope_Id) then
2652 Call := (Make_Procedure_Call_Statement (Loc,
2653 Name => New_Reference_To
2654 (RTE (RE_Complete_Rendezvous), Loc)));
2655 Insert_Before (N, Call);
2656 -- why not insert actions here???
2659 Acc_Stat := Parent (N);
2660 while Nkind (Acc_Stat) /= N_Accept_Statement loop
2661 Acc_Stat := Parent (Acc_Stat);
2664 Lab_Node := Last (Statements
2665 (Handled_Statement_Sequence (Acc_Stat)));
2667 Goto_Stat := Make_Goto_Statement (Loc,
2668 Name => New_Occurrence_Of
2669 (Entity (Identifier (Lab_Node)), Loc));
2671 Set_Analyzed (Goto_Stat);
2673 Rewrite (N, Goto_Stat);
2676 -- If it is a return from an entry body, put a Complete_Entry_Body
2677 -- call in front of the return.
2679 elsif Is_Protected_Type (Scope_Id) then
2682 Make_Procedure_Call_Statement (Loc,
2683 Name => New_Reference_To
2684 (RTE (RE_Complete_Entry_Body), Loc),
2685 Parameter_Associations => New_List
2686 (Make_Attribute_Reference (Loc,
2690 (Corresponding_Body (Parent (Scope_Id))),
2692 Attribute_Name => Name_Unchecked_Access)));
2694 Insert_Before (N, Call);
2703 Return_Type := Etype (Scope_Id);
2704 Utyp := Underlying_Type (Return_Type);
2706 -- Check the result expression of a scalar function against
2707 -- the subtype of the function by inserting a conversion.
2708 -- This conversion must eventually be performed for other
2709 -- classes of types, but for now it's only done for scalars.
2712 if Is_Scalar_Type (T) then
2713 Rewrite (Exp, Convert_To (Return_Type, Exp));
2717 -- Implement the rules of 6.5(8-10), which require a tag check in
2718 -- the case of a limited tagged return type, and tag reassignment
2719 -- for nonlimited tagged results. These actions are needed when
2720 -- the return type is a specific tagged type and the result
2721 -- expression is a conversion or a formal parameter, because in
2722 -- that case the tag of the expression might differ from the tag
2723 -- of the specific result type.
2725 if Is_Tagged_Type (Utyp)
2726 and then not Is_Class_Wide_Type (Utyp)
2727 and then (Nkind (Exp) = N_Type_Conversion
2728 or else Nkind (Exp) = N_Unchecked_Type_Conversion
2729 or else (Is_Entity_Name (Exp)
2730 and then Ekind (Entity (Exp)) in Formal_Kind))
2732 -- When the return type is limited, perform a check that the
2733 -- tag of the result is the same as the tag of the return type.
2735 if Is_Limited_Type (Return_Type) then
2737 Make_Raise_Constraint_Error (Loc,
2741 Make_Selected_Component (Loc,
2742 Prefix => Duplicate_Subexpr (Exp),
2744 New_Reference_To (Tag_Component (Utyp), Loc)),
2746 Unchecked_Convert_To (RTE (RE_Tag),
2748 (Access_Disp_Table (Base_Type (Utyp)), Loc))),
2749 Reason => CE_Tag_Check_Failed));
2751 -- If the result type is a specific nonlimited tagged type,
2752 -- then we have to ensure that the tag of the result is that
2753 -- of the result type. This is handled by making a copy of the
2754 -- expression in the case where it might have a different tag,
2755 -- namely when the expression is a conversion or a formal
2756 -- parameter. We create a new object of the result type and
2757 -- initialize it from the expression, which will implicitly
2758 -- force the tag to be set appropriately.
2762 Make_Defining_Identifier (Loc, New_Internal_Name ('R'));
2763 Result_Exp := New_Reference_To (Result_Id, Loc);
2766 Make_Object_Declaration (Loc,
2767 Defining_Identifier => Result_Id,
2768 Object_Definition => New_Reference_To (Return_Type, Loc),
2769 Constant_Present => True,
2770 Expression => Relocate_Node (Exp));
2772 Set_Assignment_OK (Result_Obj);
2773 Insert_Action (Exp, Result_Obj);
2775 Rewrite (Exp, Result_Exp);
2776 Analyze_And_Resolve (Exp, Return_Type);
2780 -- Deal with returning variable length objects and controlled types
2782 -- Nothing to do if we are returning by reference, or this is not
2783 -- a type that requires special processing (indicated by the fact
2784 -- that it requires a cleanup scope for the secondary stack case)
2786 if Is_Return_By_Reference_Type (T)
2787 or else not Requires_Transient_Scope (Return_Type)
2791 -- Case of secondary stack not used
2793 elsif Function_Returns_With_DSP (Scope_Id) then
2795 -- Here what we need to do is to always return by reference, since
2796 -- we will return with the stack pointer depressed. We may need to
2797 -- do a copy to a local temporary before doing this return.
2799 No_Secondary_Stack_Case : declare
2800 Local_Copy_Required : Boolean := False;
2801 -- Set to True if a local copy is required
2803 Copy_Ent : Entity_Id;
2804 -- Used for the target entity if a copy is required
2807 -- Declaration used to create copy if needed
2809 procedure Test_Copy_Required (Expr : Node_Id);
2810 -- Determines if Expr represents a return value for which a
2811 -- copy is required. More specifically, a copy is not required
2812 -- if Expr represents an object or component of an object that
2813 -- is either in the local subprogram frame, or is constant.
2814 -- If a copy is required, then Local_Copy_Required is set True.
2816 ------------------------
2817 -- Test_Copy_Required --
2818 ------------------------
2820 procedure Test_Copy_Required (Expr : Node_Id) is
2824 -- If component, test prefix (object containing component)
2826 if Nkind (Expr) = N_Indexed_Component
2828 Nkind (Expr) = N_Selected_Component
2830 Test_Copy_Required (Prefix (Expr));
2833 -- See if we have an entity name
2835 elsif Is_Entity_Name (Expr) then
2836 Ent := Entity (Expr);
2838 -- Constant entity is always OK, no copy required
2840 if Ekind (Ent) = E_Constant then
2843 -- No copy required for local variable
2845 elsif Ekind (Ent) = E_Variable
2846 and then Scope (Ent) = Current_Subprogram
2852 -- All other cases require a copy
2854 Local_Copy_Required := True;
2855 end Test_Copy_Required;
2857 -- Start of processing for No_Secondary_Stack_Case
2860 -- No copy needed if result is from a function call.
2861 -- In this case the result is already being returned by
2862 -- reference with the stack pointer depressed.
2864 -- To make up for a gcc 2.8.1 deficiency (???), we perform
2865 -- the copy for array types if the constrained status of the
2866 -- target type is different from that of the expression.
2868 if Requires_Transient_Scope (T)
2870 (not Is_Array_Type (T)
2871 or else Is_Constrained (T) = Is_Constrained (Return_Type)
2872 or else Controlled_Type (T))
2873 and then Nkind (Exp) = N_Function_Call
2877 -- We always need a local copy for a controlled type, since
2878 -- we are required to finalize the local value before return.
2879 -- The copy will automatically include the required finalize.
2880 -- Moreover, gigi cannot make this copy, since we need special
2881 -- processing to ensure proper behavior for finalization.
2883 -- Note: the reason we are returning with a depressed stack
2884 -- pointer in the controlled case (even if the type involved
2885 -- is constrained) is that we must make a local copy to deal
2886 -- properly with the requirement that the local result be
2889 elsif Controlled_Type (Utyp) then
2891 Make_Defining_Identifier (Loc,
2892 Chars => New_Internal_Name ('R'));
2894 -- Build declaration to do the copy, and insert it, setting
2895 -- Assignment_OK, because we may be copying a limited type.
2896 -- In addition we set the special flag to inhibit finalize
2897 -- attachment if this is a controlled type (since this attach
2898 -- must be done by the caller, otherwise if we attach it here
2899 -- we will finalize the returned result prematurely).
2902 Make_Object_Declaration (Loc,
2903 Defining_Identifier => Copy_Ent,
2904 Object_Definition => New_Occurrence_Of (Return_Type, Loc),
2905 Expression => Relocate_Node (Exp));
2907 Set_Assignment_OK (Decl);
2908 Set_Delay_Finalize_Attach (Decl);
2909 Insert_Action (N, Decl);
2911 -- Now the actual return uses the copied value
2913 Rewrite (Exp, New_Occurrence_Of (Copy_Ent, Loc));
2914 Analyze_And_Resolve (Exp, Return_Type);
2916 -- Since we have made the copy, gigi does not have to, so
2917 -- we set the By_Ref flag to prevent another copy being made.
2921 -- Non-controlled cases
2924 Test_Copy_Required (Exp);
2926 -- If a local copy is required, then gigi will make the
2927 -- copy, otherwise, we can return the result directly,
2928 -- so set By_Ref to suppress the gigi copy.
2930 if not Local_Copy_Required then
2934 end No_Secondary_Stack_Case;
2936 -- Here if secondary stack is used
2939 -- Make sure that no surrounding block will reclaim the
2940 -- secondary-stack on which we are going to put the result.
2941 -- Not only may this introduce secondary stack leaks but worse,
2942 -- if the reclamation is done too early, then the result we are
2943 -- returning may get clobbered. See example in 7417-003.
2946 S : Entity_Id := Current_Scope;
2949 while Ekind (S) = E_Block or else Ekind (S) = E_Loop loop
2950 Set_Sec_Stack_Needed_For_Return (S, True);
2951 S := Enclosing_Dynamic_Scope (S);
2955 -- Optimize the case where the result is a function call. In this
2956 -- case either the result is already on the secondary stack, or is
2957 -- already being returned with the stack pointer depressed and no
2958 -- further processing is required except to set the By_Ref flag to
2959 -- ensure that gigi does not attempt an extra unnecessary copy.
2960 -- (actually not just unnecessary but harmfully wrong in the case
2961 -- of a controlled type, where gigi does not know how to do a copy).
2962 -- To make up for a gcc 2.8.1 deficiency (???), we perform
2963 -- the copy for array types if the constrained status of the
2964 -- target type is different from that of the expression.
2966 if Requires_Transient_Scope (T)
2968 (not Is_Array_Type (T)
2969 or else Is_Constrained (T) = Is_Constrained (Return_Type)
2970 or else Controlled_Type (T))
2971 and then Nkind (Exp) = N_Function_Call
2975 -- For controlled types, do the allocation on the sec-stack
2976 -- manually in order to call adjust at the right time
2977 -- type Anon1 is access Return_Type;
2978 -- for Anon1'Storage_pool use ss_pool;
2979 -- Anon2 : anon1 := new Return_Type'(expr);
2980 -- return Anon2.all;
2982 elsif Controlled_Type (Utyp) then
2984 Loc : constant Source_Ptr := Sloc (N);
2985 Temp : constant Entity_Id :=
2986 Make_Defining_Identifier (Loc,
2987 Chars => New_Internal_Name ('R'));
2988 Acc_Typ : constant Entity_Id :=
2989 Make_Defining_Identifier (Loc,
2990 Chars => New_Internal_Name ('A'));
2991 Alloc_Node : Node_Id;
2994 Set_Ekind (Acc_Typ, E_Access_Type);
2996 Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_SS_Pool));
2999 Make_Allocator (Loc,
3001 Make_Qualified_Expression (Loc,
3002 Subtype_Mark => New_Reference_To (Etype (Exp), Loc),
3003 Expression => Relocate_Node (Exp)));
3005 Insert_List_Before_And_Analyze (N, New_List (
3006 Make_Full_Type_Declaration (Loc,
3007 Defining_Identifier => Acc_Typ,
3009 Make_Access_To_Object_Definition (Loc,
3010 Subtype_Indication =>
3011 New_Reference_To (Return_Type, Loc))),
3013 Make_Object_Declaration (Loc,
3014 Defining_Identifier => Temp,
3015 Object_Definition => New_Reference_To (Acc_Typ, Loc),
3016 Expression => Alloc_Node)));
3019 Make_Explicit_Dereference (Loc,
3020 Prefix => New_Reference_To (Temp, Loc)));
3022 Analyze_And_Resolve (Exp, Return_Type);
3025 -- Otherwise use the gigi mechanism to allocate result on the
3029 Set_Storage_Pool (N, RTE (RE_SS_Pool));
3031 -- If we are generating code for the Java VM do not use
3032 -- SS_Allocate since everything is heap-allocated anyway.
3035 Set_Procedure_To_Call (N, RTE (RE_SS_Allocate));
3041 when RE_Not_Available =>
3043 end Expand_N_Return_Statement;
3045 ------------------------------
3046 -- Make_Tag_Ctrl_Assignment --
3047 ------------------------------
3049 function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id is
3050 Loc : constant Source_Ptr := Sloc (N);
3051 L : constant Node_Id := Name (N);
3052 T : constant Entity_Id := Underlying_Type (Etype (L));
3054 Ctrl_Act : constant Boolean := Controlled_Type (T)
3055 and then not No_Ctrl_Actions (N);
3057 Save_Tag : constant Boolean := Is_Tagged_Type (T)
3058 and then not No_Ctrl_Actions (N)
3059 and then not Java_VM;
3060 -- Tags are not saved and restored when Java_VM because JVM tags
3061 -- are represented implicitly in objects.
3064 Tag_Tmp : Entity_Id;
3065 Prev_Tmp : Entity_Id;
3066 Next_Tmp : Entity_Id;
3068 Ctrl_Ref2 : Node_Id := Empty;
3069 Prev_Tmp2 : Entity_Id := Empty; -- prevent warning
3070 Next_Tmp2 : Entity_Id := Empty; -- prevent warning
3075 -- Finalize the target of the assignment when controlled.
3076 -- We have two exceptions here:
3078 -- 1. If we are in an init proc since it is an initialization
3079 -- more than an assignment
3081 -- 2. If the left-hand side is a temporary that was not initialized
3082 -- (or the parent part of a temporary since it is the case in
3083 -- extension aggregates). Such a temporary does not come from
3084 -- source. We must examine the original node for the prefix, because
3085 -- it may be a component of an entry formal, in which case it has
3086 -- been rewritten and does not appear to come from source either.
3088 -- Case of init proc
3090 if not Ctrl_Act then
3093 -- The left hand side is an uninitialized temporary
3095 elsif Nkind (L) = N_Type_Conversion
3096 and then Is_Entity_Name (Expression (L))
3097 and then No_Initialization (Parent (Entity (Expression (L))))
3101 Append_List_To (Res,
3103 Ref => Duplicate_Subexpr_No_Checks (L),
3105 With_Detach => New_Reference_To (Standard_False, Loc)));
3108 Next_Tmp := Make_Defining_Identifier (Loc, New_Internal_Name ('C'));
3110 -- Save the Tag in a local variable Tag_Tmp
3114 Make_Defining_Identifier (Loc, New_Internal_Name ('A'));
3117 Make_Object_Declaration (Loc,
3118 Defining_Identifier => Tag_Tmp,
3119 Object_Definition => New_Reference_To (RTE (RE_Tag), Loc),
3121 Make_Selected_Component (Loc,
3122 Prefix => Duplicate_Subexpr_No_Checks (L),
3123 Selector_Name => New_Reference_To (Tag_Component (T), Loc))));
3125 -- Otherwise Tag_Tmp not used
3131 -- Save the Finalization Pointers in local variables Prev_Tmp and
3132 -- Next_Tmp. For objects with Has_Controlled_Component set, these
3133 -- pointers are in the Record_Controller and if it is also
3134 -- Is_Controlled, we need to save the object pointers as well.
3137 Ctrl_Ref := Duplicate_Subexpr_No_Checks (L);
3139 if Has_Controlled_Component (T) then
3141 Make_Selected_Component (Loc,
3144 New_Reference_To (Controller_Component (T), Loc));
3146 if Is_Controlled (T) then
3147 Ctrl_Ref2 := Duplicate_Subexpr_No_Checks (L);
3151 Prev_Tmp := Make_Defining_Identifier (Loc, New_Internal_Name ('B'));
3154 Make_Object_Declaration (Loc,
3155 Defining_Identifier => Prev_Tmp,
3157 Object_Definition =>
3158 New_Reference_To (RTE (RE_Finalizable_Ptr), Loc),
3161 Make_Selected_Component (Loc,
3163 Unchecked_Convert_To (RTE (RE_Finalizable), Ctrl_Ref),
3164 Selector_Name => Make_Identifier (Loc, Name_Prev))));
3166 Next_Tmp := Make_Defining_Identifier (Loc, New_Internal_Name ('C'));
3169 Make_Object_Declaration (Loc,
3170 Defining_Identifier => Next_Tmp,
3172 Object_Definition =>
3173 New_Reference_To (RTE (RE_Finalizable_Ptr), Loc),
3176 Make_Selected_Component (Loc,
3178 Unchecked_Convert_To (RTE (RE_Finalizable),
3179 New_Copy_Tree (Ctrl_Ref)),
3180 Selector_Name => Make_Identifier (Loc, Name_Next))));
3182 if Present (Ctrl_Ref2) then
3184 Make_Defining_Identifier (Loc, New_Internal_Name ('B'));
3187 Make_Object_Declaration (Loc,
3188 Defining_Identifier => Prev_Tmp2,
3190 Object_Definition =>
3191 New_Reference_To (RTE (RE_Finalizable_Ptr), Loc),
3194 Make_Selected_Component (Loc,
3196 Unchecked_Convert_To (RTE (RE_Finalizable), Ctrl_Ref2),
3197 Selector_Name => Make_Identifier (Loc, Name_Prev))));
3200 Make_Defining_Identifier (Loc, New_Internal_Name ('C'));
3203 Make_Object_Declaration (Loc,
3204 Defining_Identifier => Next_Tmp2,
3206 Object_Definition =>
3207 New_Reference_To (RTE (RE_Finalizable_Ptr), Loc),
3210 Make_Selected_Component (Loc,
3212 Unchecked_Convert_To (RTE (RE_Finalizable),
3213 New_Copy_Tree (Ctrl_Ref2)),
3214 Selector_Name => Make_Identifier (Loc, Name_Next))));
3217 -- If not controlled type, then Prev_Tmp and Ctrl_Ref unused
3224 -- Do the Assignment
3226 Append_To (Res, Relocate_Node (N));
3232 Make_Assignment_Statement (Loc,
3234 Make_Selected_Component (Loc,
3235 Prefix => Duplicate_Subexpr_No_Checks (L),
3236 Selector_Name => New_Reference_To (Tag_Component (T), Loc)),
3237 Expression => New_Reference_To (Tag_Tmp, Loc)));
3240 -- Restore the finalization pointers
3244 Make_Assignment_Statement (Loc,
3246 Make_Selected_Component (Loc,
3248 Unchecked_Convert_To (RTE (RE_Finalizable),
3249 New_Copy_Tree (Ctrl_Ref)),
3250 Selector_Name => Make_Identifier (Loc, Name_Prev)),
3251 Expression => New_Reference_To (Prev_Tmp, Loc)));
3254 Make_Assignment_Statement (Loc,
3256 Make_Selected_Component (Loc,
3258 Unchecked_Convert_To (RTE (RE_Finalizable),
3259 New_Copy_Tree (Ctrl_Ref)),
3260 Selector_Name => Make_Identifier (Loc, Name_Next)),
3261 Expression => New_Reference_To (Next_Tmp, Loc)));
3263 if Present (Ctrl_Ref2) then
3265 Make_Assignment_Statement (Loc,
3267 Make_Selected_Component (Loc,
3269 Unchecked_Convert_To (RTE (RE_Finalizable),
3270 New_Copy_Tree (Ctrl_Ref2)),
3271 Selector_Name => Make_Identifier (Loc, Name_Prev)),
3272 Expression => New_Reference_To (Prev_Tmp2, Loc)));
3275 Make_Assignment_Statement (Loc,
3277 Make_Selected_Component (Loc,
3279 Unchecked_Convert_To (RTE (RE_Finalizable),
3280 New_Copy_Tree (Ctrl_Ref2)),
3281 Selector_Name => Make_Identifier (Loc, Name_Next)),
3282 Expression => New_Reference_To (Next_Tmp2, Loc)));
3286 -- Adjust the target after the assignment when controlled. (not in
3287 -- the init proc since it is an initialization more than an
3291 Append_List_To (Res,
3293 Ref => Duplicate_Subexpr_Move_Checks (L),
3295 Flist_Ref => New_Reference_To (RTE (RE_Global_Final_List), Loc),
3296 With_Attach => Make_Integer_Literal (Loc, 0)));
3302 when RE_Not_Available =>
3304 end Make_Tag_Ctrl_Assignment;
3306 ------------------------------------
3307 -- Possible_Bit_Aligned_Component --
3308 ------------------------------------
3310 function Possible_Bit_Aligned_Component (N : Node_Id) return Boolean is
3314 -- Case of indexed component
3316 when N_Indexed_Component =>
3318 P : constant Node_Id := Prefix (N);
3319 Ptyp : constant Entity_Id := Etype (P);
3322 -- If we know the component size and it is less than 64, then
3323 -- we are definitely OK. The back end always does assignment
3324 -- of misaligned small objects correctly.
3326 if Known_Static_Component_Size (Ptyp)
3327 and then Component_Size (Ptyp) <= 64
3331 -- Otherwise, we need to test the prefix, to see if we are
3332 -- indexing from a possibly unaligned component.
3335 return Possible_Bit_Aligned_Component (P);
3339 -- Case of selected component
3341 when N_Selected_Component =>
3343 P : constant Node_Id := Prefix (N);
3344 Comp : constant Entity_Id := Entity (Selector_Name (N));
3347 -- If there is no component clause, then we are in the clear
3348 -- since the back end will never misalign a large component
3349 -- unless it is forced to do so. In the clear means we need
3350 -- only the recursive test on the prefix.
3352 if Component_May_Be_Bit_Aligned (Comp) then
3355 return Possible_Bit_Aligned_Component (P);
3359 -- If we have neither a record nor array component, it means that
3360 -- we have fallen off the top testing prefixes recursively, and
3361 -- we now have a stand alone object, where we don't have a problem
3367 end Possible_Bit_Aligned_Component;