1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2015, 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 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Aspects
; use Aspects
;
27 with Atree
; use Atree
;
28 with Checks
; use Checks
;
29 with Debug
; use Debug
;
30 with Einfo
; use Einfo
;
31 with Elists
; use Elists
;
32 with Errout
; use Errout
;
33 with Exp_Aggr
; use Exp_Aggr
;
34 with Exp_Ch6
; use Exp_Ch6
;
35 with Exp_Ch7
; use Exp_Ch7
;
36 with Exp_Ch11
; use Exp_Ch11
;
37 with Exp_Dbug
; use Exp_Dbug
;
38 with Exp_Pakd
; use Exp_Pakd
;
39 with Exp_Tss
; use Exp_Tss
;
40 with Exp_Util
; use Exp_Util
;
41 with Ghost
; use Ghost
;
42 with Inline
; use Inline
;
43 with Namet
; use Namet
;
44 with Nlists
; use Nlists
;
45 with Nmake
; use Nmake
;
47 with Restrict
; use Restrict
;
48 with Rident
; use Rident
;
49 with Rtsfind
; use Rtsfind
;
50 with Sinfo
; use Sinfo
;
52 with Sem_Aux
; use Sem_Aux
;
53 with Sem_Ch3
; use Sem_Ch3
;
54 with Sem_Ch8
; use Sem_Ch8
;
55 with Sem_Ch13
; use Sem_Ch13
;
56 with Sem_Eval
; use Sem_Eval
;
57 with Sem_Res
; use Sem_Res
;
58 with Sem_Util
; use Sem_Util
;
59 with Snames
; use Snames
;
60 with Stand
; use Stand
;
61 with Stringt
; use Stringt
;
62 with Targparm
; use Targparm
;
63 with Tbuild
; use Tbuild
;
64 with Uintp
; use Uintp
;
65 with Validsw
; use Validsw
;
67 package body Exp_Ch5
is
69 procedure Build_Formal_Container_Iteration
71 Container
: Entity_Id
;
74 Advance
: out Node_Id
;
75 New_Loop
: out Node_Id
);
76 -- Utility to create declarations and loop statement for both forms
77 -- of formal container iterators.
79 function Change_Of_Representation
(N
: Node_Id
) return Boolean;
80 -- Determine if the right hand side of assignment N is a type conversion
81 -- which requires a change of representation. Called only for the array
84 procedure Expand_Assign_Array
(N
: Node_Id
; Rhs
: Node_Id
);
85 -- N is an assignment which assigns an array value. This routine process
86 -- the various special cases and checks required for such assignments,
87 -- including change of representation. Rhs is normally simply the right
88 -- hand side of the assignment, except that if the right hand side is a
89 -- type conversion or a qualified expression, then the RHS is the actual
90 -- expression inside any such type conversions or qualifications.
92 function Expand_Assign_Array_Loop
99 Rev
: Boolean) return Node_Id
;
100 -- N is an assignment statement which assigns an array value. This routine
101 -- expands the assignment into a loop (or nested loops for the case of a
102 -- multi-dimensional array) to do the assignment component by component.
103 -- Larray and Rarray are the entities of the actual arrays on the left
104 -- hand and right hand sides. L_Type and R_Type are the types of these
105 -- arrays (which may not be the same, due to either sliding, or to a
106 -- change of representation case). Ndim is the number of dimensions and
107 -- the parameter Rev indicates if the loops run normally (Rev = False),
108 -- or reversed (Rev = True). The value returned is the constructed
109 -- loop statement. Auxiliary declarations are inserted before node N
110 -- using the standard Insert_Actions mechanism.
112 procedure Expand_Assign_Record
(N
: Node_Id
);
113 -- N is an assignment of an untagged record value. This routine handles
114 -- the case where the assignment must be made component by component,
115 -- either because the target is not byte aligned, or there is a change
116 -- of representation, or when we have a tagged type with a representation
117 -- clause (this last case is required because holes in the tagged type
118 -- might be filled with components from child types).
120 procedure Expand_Formal_Container_Loop
(N
: Node_Id
);
121 -- Use the primitives specified in an Iterable aspect to expand a loop
122 -- over a so-called formal container, primarily for SPARK usage.
124 procedure Expand_Formal_Container_Element_Loop
(N
: Node_Id
);
125 -- Same, for an iterator of the form " For E of C". In this case the
126 -- iterator provides the name of the element, and the cursor is generated
129 procedure Expand_Iterator_Loop
(N
: Node_Id
);
130 -- Expand loop over arrays and containers that uses the form "for X of C"
131 -- with an optional subtype mark, or "for Y in C".
133 procedure Expand_Iterator_Loop_Over_Array
(N
: Node_Id
);
134 -- Expand loop over arrays that uses the form "for X of C"
136 procedure Expand_Iterator_Loop_Over_Container
141 Container_Typ
: Entity_Id
);
142 -- Expand loop over containers that uses the form "for X of C" with an
143 -- optional subtype mark, or "for Y in C". Isc is the iteration scheme.
144 -- I_Spec is the iterator specification and Container is either the
145 -- Container (for OF) or the iterator (for IN).
147 procedure Expand_Predicated_Loop
(N
: Node_Id
);
148 -- Expand for loop over predicated subtype
150 function Make_Tag_Ctrl_Assignment
(N
: Node_Id
) return List_Id
;
151 -- Generate the necessary code for controlled and tagged assignment, that
152 -- is to say, finalization of the target before, adjustment of the target
153 -- after and save and restore of the tag and finalization pointers which
154 -- are not 'part of the value' and must not be changed upon assignment. N
155 -- is the original Assignment node.
157 --------------------------------------
158 -- Build_Formal_Container_iteration --
159 --------------------------------------
161 procedure Build_Formal_Container_Iteration
163 Container
: Entity_Id
;
166 Advance
: out Node_Id
;
167 New_Loop
: out Node_Id
)
169 Loc
: constant Source_Ptr
:= Sloc
(N
);
170 Stats
: constant List_Id
:= Statements
(N
);
171 Typ
: constant Entity_Id
:= Base_Type
(Etype
(Container
));
172 First_Op
: constant Entity_Id
:=
173 Get_Iterable_Type_Primitive
(Typ
, Name_First
);
174 Next_Op
: constant Entity_Id
:=
175 Get_Iterable_Type_Primitive
(Typ
, Name_Next
);
177 Has_Element_Op
: constant Entity_Id
:=
178 Get_Iterable_Type_Primitive
(Typ
, Name_Has_Element
);
180 -- Declaration for Cursor
183 Make_Object_Declaration
(Loc
,
184 Defining_Identifier
=> Cursor
,
185 Object_Definition
=> New_Occurrence_Of
(Etype
(First_Op
), Loc
),
187 Make_Function_Call
(Loc
,
188 Name
=> New_Occurrence_Of
(First_Op
, Loc
),
189 Parameter_Associations
=> New_List
(
190 New_Occurrence_Of
(Container
, Loc
))));
192 -- Statement that advances cursor in loop
195 Make_Assignment_Statement
(Loc
,
196 Name
=> New_Occurrence_Of
(Cursor
, Loc
),
198 Make_Function_Call
(Loc
,
199 Name
=> New_Occurrence_Of
(Next_Op
, Loc
),
200 Parameter_Associations
=> New_List
(
201 New_Occurrence_Of
(Container
, Loc
),
202 New_Occurrence_Of
(Cursor
, Loc
))));
204 -- Iterator is rewritten as a while_loop
207 Make_Loop_Statement
(Loc
,
209 Make_Iteration_Scheme
(Loc
,
211 Make_Function_Call
(Loc
,
212 Name
=> New_Occurrence_Of
(Has_Element_Op
, Loc
),
213 Parameter_Associations
=> New_List
(
214 New_Occurrence_Of
(Container
, Loc
),
215 New_Occurrence_Of
(Cursor
, Loc
)))),
218 end Build_Formal_Container_Iteration
;
220 ------------------------------
221 -- Change_Of_Representation --
222 ------------------------------
224 function Change_Of_Representation
(N
: Node_Id
) return Boolean is
225 Rhs
: constant Node_Id
:= Expression
(N
);
228 Nkind
(Rhs
) = N_Type_Conversion
230 not Same_Representation
(Etype
(Rhs
), Etype
(Expression
(Rhs
)));
231 end Change_Of_Representation
;
233 -------------------------
234 -- Expand_Assign_Array --
235 -------------------------
237 -- There are two issues here. First, do we let Gigi do a block move, or
238 -- do we expand out into a loop? Second, we need to set the two flags
239 -- Forwards_OK and Backwards_OK which show whether the block move (or
240 -- corresponding loops) can be legitimately done in a forwards (low to
241 -- high) or backwards (high to low) manner.
243 procedure Expand_Assign_Array
(N
: Node_Id
; Rhs
: Node_Id
) is
244 Loc
: constant Source_Ptr
:= Sloc
(N
);
246 Lhs
: constant Node_Id
:= Name
(N
);
248 Act_Lhs
: constant Node_Id
:= Get_Referenced_Object
(Lhs
);
249 Act_Rhs
: Node_Id
:= Get_Referenced_Object
(Rhs
);
251 L_Type
: constant Entity_Id
:=
252 Underlying_Type
(Get_Actual_Subtype
(Act_Lhs
));
253 R_Type
: Entity_Id
:=
254 Underlying_Type
(Get_Actual_Subtype
(Act_Rhs
));
256 L_Slice
: constant Boolean := Nkind
(Act_Lhs
) = N_Slice
;
257 R_Slice
: constant Boolean := Nkind
(Act_Rhs
) = N_Slice
;
259 Crep
: constant Boolean := Change_Of_Representation
(N
);
264 Ndim
: constant Pos
:= Number_Dimensions
(L_Type
);
266 Loop_Required
: Boolean := False;
267 -- This switch is set to True if the array move must be done using
268 -- an explicit front end generated loop.
270 procedure Apply_Dereference
(Arg
: Node_Id
);
271 -- If the argument is an access to an array, and the assignment is
272 -- converted into a procedure call, apply explicit dereference.
274 function Has_Address_Clause
(Exp
: Node_Id
) return Boolean;
275 -- Test if Exp is a reference to an array whose declaration has
276 -- an address clause, or it is a slice of such an array.
278 function Is_Formal_Array
(Exp
: Node_Id
) return Boolean;
279 -- Test if Exp is a reference to an array which is either a formal
280 -- parameter or a slice of a formal parameter. These are the cases
281 -- where hidden aliasing can occur.
283 function Is_Non_Local_Array
(Exp
: Node_Id
) return Boolean;
284 -- Determine if Exp is a reference to an array variable which is other
285 -- than an object defined in the current scope, or a slice of such
286 -- an object. Such objects can be aliased to parameters (unlike local
287 -- array references).
289 -----------------------
290 -- Apply_Dereference --
291 -----------------------
293 procedure Apply_Dereference
(Arg
: Node_Id
) is
294 Typ
: constant Entity_Id
:= Etype
(Arg
);
296 if Is_Access_Type
(Typ
) then
297 Rewrite
(Arg
, Make_Explicit_Dereference
(Loc
,
298 Prefix
=> Relocate_Node
(Arg
)));
299 Analyze_And_Resolve
(Arg
, Designated_Type
(Typ
));
301 end Apply_Dereference
;
303 ------------------------
304 -- Has_Address_Clause --
305 ------------------------
307 function Has_Address_Clause
(Exp
: Node_Id
) return Boolean is
310 (Is_Entity_Name
(Exp
) and then
311 Present
(Address_Clause
(Entity
(Exp
))))
313 (Nkind
(Exp
) = N_Slice
and then Has_Address_Clause
(Prefix
(Exp
)));
314 end Has_Address_Clause
;
316 ---------------------
317 -- Is_Formal_Array --
318 ---------------------
320 function Is_Formal_Array
(Exp
: Node_Id
) return Boolean is
323 (Is_Entity_Name
(Exp
) and then Is_Formal
(Entity
(Exp
)))
325 (Nkind
(Exp
) = N_Slice
and then Is_Formal_Array
(Prefix
(Exp
)));
328 ------------------------
329 -- Is_Non_Local_Array --
330 ------------------------
332 function Is_Non_Local_Array
(Exp
: Node_Id
) return Boolean is
334 return (Is_Entity_Name
(Exp
)
335 and then Scope
(Entity
(Exp
)) /= Current_Scope
)
336 or else (Nkind
(Exp
) = N_Slice
337 and then Is_Non_Local_Array
(Prefix
(Exp
)));
338 end Is_Non_Local_Array
;
340 -- Determine if Lhs, Rhs are formal arrays or nonlocal arrays
342 Lhs_Formal
: constant Boolean := Is_Formal_Array
(Act_Lhs
);
343 Rhs_Formal
: constant Boolean := Is_Formal_Array
(Act_Rhs
);
345 Lhs_Non_Local_Var
: constant Boolean := Is_Non_Local_Array
(Act_Lhs
);
346 Rhs_Non_Local_Var
: constant Boolean := Is_Non_Local_Array
(Act_Rhs
);
348 -- Start of processing for Expand_Assign_Array
351 -- Deal with length check. Note that the length check is done with
352 -- respect to the right hand side as given, not a possible underlying
353 -- renamed object, since this would generate incorrect extra checks.
355 Apply_Length_Check
(Rhs
, L_Type
);
357 -- We start by assuming that the move can be done in either direction,
358 -- i.e. that the two sides are completely disjoint.
360 Set_Forwards_OK
(N
, True);
361 Set_Backwards_OK
(N
, True);
363 -- Normally it is only the slice case that can lead to overlap, and
364 -- explicit checks for slices are made below. But there is one case
365 -- where the slice can be implicit and invisible to us: when we have a
366 -- one dimensional array, and either both operands are parameters, or
367 -- one is a parameter (which can be a slice passed by reference) and the
368 -- other is a non-local variable. In this case the parameter could be a
369 -- slice that overlaps with the other operand.
371 -- However, if the array subtype is a constrained first subtype in the
372 -- parameter case, then we don't have to worry about overlap, since
373 -- slice assignments aren't possible (other than for a slice denoting
376 -- Note: No overlap is possible if there is a change of representation,
377 -- so we can exclude this case.
382 ((Lhs_Formal
and Rhs_Formal
)
384 (Lhs_Formal
and Rhs_Non_Local_Var
)
386 (Rhs_Formal
and Lhs_Non_Local_Var
))
388 (not Is_Constrained
(Etype
(Lhs
))
389 or else not Is_First_Subtype
(Etype
(Lhs
)))
391 -- In the case of compiling for the Java or .NET Virtual Machine,
392 -- slices are always passed by making a copy, so we don't have to
393 -- worry about overlap. We also want to prevent generation of "<"
394 -- comparisons for array addresses, since that's a meaningless
395 -- operation on the VM.
397 and then VM_Target
= No_VM
399 Set_Forwards_OK
(N
, False);
400 Set_Backwards_OK
(N
, False);
402 -- Note: the bit-packed case is not worrisome here, since if we have
403 -- a slice passed as a parameter, it is always aligned on a byte
404 -- boundary, and if there are no explicit slices, the assignment
405 -- can be performed directly.
408 -- If either operand has an address clause clear Backwards_OK and
409 -- Forwards_OK, since we cannot tell if the operands overlap. We
410 -- exclude this treatment when Rhs is an aggregate, since we know
411 -- that overlap can't occur.
413 if (Has_Address_Clause
(Lhs
) and then Nkind
(Rhs
) /= N_Aggregate
)
414 or else Has_Address_Clause
(Rhs
)
416 Set_Forwards_OK
(N
, False);
417 Set_Backwards_OK
(N
, False);
420 -- We certainly must use a loop for change of representation and also
421 -- we use the operand of the conversion on the right hand side as the
422 -- effective right hand side (the component types must match in this
426 Act_Rhs
:= Get_Referenced_Object
(Rhs
);
427 R_Type
:= Get_Actual_Subtype
(Act_Rhs
);
428 Loop_Required
:= True;
430 -- We require a loop if the left side is possibly bit unaligned
432 elsif Possible_Bit_Aligned_Component
(Lhs
)
434 Possible_Bit_Aligned_Component
(Rhs
)
436 Loop_Required
:= True;
438 -- Arrays with controlled components are expanded into a loop to force
439 -- calls to Adjust at the component level.
441 elsif Has_Controlled_Component
(L_Type
) then
442 Loop_Required
:= True;
444 -- If object is atomic/VFA, we cannot tolerate a loop
446 elsif Is_Atomic_Or_VFA_Object
(Act_Lhs
)
448 Is_Atomic_Or_VFA_Object
(Act_Rhs
)
452 -- Loop is required if we have atomic components since we have to
453 -- be sure to do any accesses on an element by element basis.
455 elsif Has_Atomic_Components
(L_Type
)
456 or else Has_Atomic_Components
(R_Type
)
457 or else Is_Atomic_Or_VFA
(Component_Type
(L_Type
))
458 or else Is_Atomic_Or_VFA
(Component_Type
(R_Type
))
460 Loop_Required
:= True;
462 -- Case where no slice is involved
464 elsif not L_Slice
and not R_Slice
then
466 -- The following code deals with the case of unconstrained bit packed
467 -- arrays. The problem is that the template for such arrays contains
468 -- the bounds of the actual source level array, but the copy of an
469 -- entire array requires the bounds of the underlying array. It would
470 -- be nice if the back end could take care of this, but right now it
471 -- does not know how, so if we have such a type, then we expand out
472 -- into a loop, which is inefficient but works correctly. If we don't
473 -- do this, we get the wrong length computed for the array to be
474 -- moved. The two cases we need to worry about are:
476 -- Explicit dereference of an unconstrained packed array type as in
477 -- the following example:
480 -- type BITS is array(INTEGER range <>) of BOOLEAN;
481 -- pragma PACK(BITS);
482 -- type A is access BITS;
485 -- P1 := new BITS (1 .. 65_535);
486 -- P2 := new BITS (1 .. 65_535);
490 -- A formal parameter reference with an unconstrained bit array type
491 -- is the other case we need to worry about (here we assume the same
492 -- BITS type declared above):
494 -- procedure Write_All (File : out BITS; Contents : BITS);
496 -- File.Storage := Contents;
499 -- We expand to a loop in either of these two cases
501 -- Question for future thought. Another potentially more efficient
502 -- approach would be to create the actual subtype, and then do an
503 -- unchecked conversion to this actual subtype ???
505 Check_Unconstrained_Bit_Packed_Array
: declare
507 function Is_UBPA_Reference
(Opnd
: Node_Id
) return Boolean;
508 -- Function to perform required test for the first case, above
509 -- (dereference of an unconstrained bit packed array).
511 -----------------------
512 -- Is_UBPA_Reference --
513 -----------------------
515 function Is_UBPA_Reference
(Opnd
: Node_Id
) return Boolean is
516 Typ
: constant Entity_Id
:= Underlying_Type
(Etype
(Opnd
));
518 Des_Type
: Entity_Id
;
521 if Present
(Packed_Array_Impl_Type
(Typ
))
522 and then Is_Array_Type
(Packed_Array_Impl_Type
(Typ
))
523 and then not Is_Constrained
(Packed_Array_Impl_Type
(Typ
))
527 elsif Nkind
(Opnd
) = N_Explicit_Dereference
then
528 P_Type
:= Underlying_Type
(Etype
(Prefix
(Opnd
)));
530 if not Is_Access_Type
(P_Type
) then
534 Des_Type
:= Designated_Type
(P_Type
);
536 Is_Bit_Packed_Array
(Des_Type
)
537 and then not Is_Constrained
(Des_Type
);
543 end Is_UBPA_Reference
;
545 -- Start of processing for Check_Unconstrained_Bit_Packed_Array
548 if Is_UBPA_Reference
(Lhs
)
550 Is_UBPA_Reference
(Rhs
)
552 Loop_Required
:= True;
554 -- Here if we do not have the case of a reference to a bit packed
555 -- unconstrained array case. In this case gigi can most certainly
556 -- handle the assignment if a forwards move is allowed.
558 -- (could it handle the backwards case also???)
560 elsif Forwards_OK
(N
) then
563 end Check_Unconstrained_Bit_Packed_Array
;
565 -- The back end can always handle the assignment if the right side is a
566 -- string literal (note that overlap is definitely impossible in this
567 -- case). If the type is packed, a string literal is always converted
568 -- into an aggregate, except in the case of a null slice, for which no
569 -- aggregate can be written. In that case, rewrite the assignment as a
570 -- null statement, a length check has already been emitted to verify
571 -- that the range of the left-hand side is empty.
573 -- Note that this code is not executed if we have an assignment of a
574 -- string literal to a non-bit aligned component of a record, a case
575 -- which cannot be handled by the backend.
577 elsif Nkind
(Rhs
) = N_String_Literal
then
578 if String_Length
(Strval
(Rhs
)) = 0
579 and then Is_Bit_Packed_Array
(L_Type
)
581 Rewrite
(N
, Make_Null_Statement
(Loc
));
587 -- If either operand is bit packed, then we need a loop, since we can't
588 -- be sure that the slice is byte aligned. Similarly, if either operand
589 -- is a possibly unaligned slice, then we need a loop (since the back
590 -- end cannot handle unaligned slices).
592 elsif Is_Bit_Packed_Array
(L_Type
)
593 or else Is_Bit_Packed_Array
(R_Type
)
594 or else Is_Possibly_Unaligned_Slice
(Lhs
)
595 or else Is_Possibly_Unaligned_Slice
(Rhs
)
597 Loop_Required
:= True;
599 -- If we are not bit-packed, and we have only one slice, then no overlap
600 -- is possible except in the parameter case, so we can let the back end
603 elsif not (L_Slice
and R_Slice
) then
604 if Forwards_OK
(N
) then
609 -- If the right-hand side is a string literal, introduce a temporary for
610 -- it, for use in the generated loop that will follow.
612 if Nkind
(Rhs
) = N_String_Literal
then
614 Temp
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', Rhs
);
619 Make_Object_Declaration
(Loc
,
620 Defining_Identifier
=> Temp
,
621 Object_Definition
=> New_Occurrence_Of
(L_Type
, Loc
),
622 Expression
=> Relocate_Node
(Rhs
));
624 Insert_Action
(N
, Decl
);
625 Rewrite
(Rhs
, New_Occurrence_Of
(Temp
, Loc
));
626 R_Type
:= Etype
(Temp
);
630 -- Come here to complete the analysis
632 -- Loop_Required: Set to True if we know that a loop is required
633 -- regardless of overlap considerations.
635 -- Forwards_OK: Set to False if we already know that a forwards
636 -- move is not safe, else set to True.
638 -- Backwards_OK: Set to False if we already know that a backwards
639 -- move is not safe, else set to True
641 -- Our task at this stage is to complete the overlap analysis, which can
642 -- result in possibly setting Forwards_OK or Backwards_OK to False, and
643 -- then generating the final code, either by deciding that it is OK
644 -- after all to let Gigi handle it, or by generating appropriate code
648 L_Index_Typ
: constant Node_Id
:= Etype
(First_Index
(L_Type
));
649 R_Index_Typ
: constant Node_Id
:= Etype
(First_Index
(R_Type
));
651 Left_Lo
: constant Node_Id
:= Type_Low_Bound
(L_Index_Typ
);
652 Left_Hi
: constant Node_Id
:= Type_High_Bound
(L_Index_Typ
);
653 Right_Lo
: constant Node_Id
:= Type_Low_Bound
(R_Index_Typ
);
654 Right_Hi
: constant Node_Id
:= Type_High_Bound
(R_Index_Typ
);
656 Act_L_Array
: Node_Id
;
657 Act_R_Array
: Node_Id
;
663 Cresult
: Compare_Result
;
666 -- Get the expressions for the arrays. If we are dealing with a
667 -- private type, then convert to the underlying type. We can do
668 -- direct assignments to an array that is a private type, but we
669 -- cannot assign to elements of the array without this extra
670 -- unchecked conversion.
672 -- Note: We propagate Parent to the conversion nodes to generate
673 -- a well-formed subtree.
675 if Nkind
(Act_Lhs
) = N_Slice
then
676 Larray
:= Prefix
(Act_Lhs
);
680 if Is_Private_Type
(Etype
(Larray
)) then
682 Par
: constant Node_Id
:= Parent
(Larray
);
686 (Underlying_Type
(Etype
(Larray
)), Larray
);
687 Set_Parent
(Larray
, Par
);
692 if Nkind
(Act_Rhs
) = N_Slice
then
693 Rarray
:= Prefix
(Act_Rhs
);
697 if Is_Private_Type
(Etype
(Rarray
)) then
699 Par
: constant Node_Id
:= Parent
(Rarray
);
703 (Underlying_Type
(Etype
(Rarray
)), Rarray
);
704 Set_Parent
(Rarray
, Par
);
709 -- If both sides are slices, we must figure out whether it is safe
710 -- to do the move in one direction or the other. It is always safe
711 -- if there is a change of representation since obviously two arrays
712 -- with different representations cannot possibly overlap.
714 if (not Crep
) and L_Slice
and R_Slice
then
715 Act_L_Array
:= Get_Referenced_Object
(Prefix
(Act_Lhs
));
716 Act_R_Array
:= Get_Referenced_Object
(Prefix
(Act_Rhs
));
718 -- If both left and right hand arrays are entity names, and refer
719 -- to different entities, then we know that the move is safe (the
720 -- two storage areas are completely disjoint).
722 if Is_Entity_Name
(Act_L_Array
)
723 and then Is_Entity_Name
(Act_R_Array
)
724 and then Entity
(Act_L_Array
) /= Entity
(Act_R_Array
)
728 -- Otherwise, we assume the worst, which is that the two arrays
729 -- are the same array. There is no need to check if we know that
730 -- is the case, because if we don't know it, we still have to
733 -- Generally if the same array is involved, then we have an
734 -- overlapping case. We will have to really assume the worst (i.e.
735 -- set neither of the OK flags) unless we can determine the lower
736 -- or upper bounds at compile time and compare them.
741 (Left_Lo
, Right_Lo
, Assume_Valid
=> True);
743 if Cresult
= Unknown
then
746 (Left_Hi
, Right_Hi
, Assume_Valid
=> True);
750 when LT | LE | EQ
=> Set_Backwards_OK
(N
, False);
751 when GT | GE
=> Set_Forwards_OK
(N
, False);
752 when NE | Unknown
=> Set_Backwards_OK
(N
, False);
753 Set_Forwards_OK
(N
, False);
758 -- If after that analysis Loop_Required is False, meaning that we
759 -- have not discovered some non-overlap reason for requiring a loop,
760 -- then the outcome depends on the capabilities of the back end.
762 if not Loop_Required
then
764 -- The GCC back end can deal with all cases of overlap by falling
765 -- back to memmove if it cannot use a more efficient approach.
767 if VM_Target
= No_VM
and not AAMP_On_Target
then
770 -- Assume other back ends can handle it if Forwards_OK is set
772 elsif Forwards_OK
(N
) then
775 -- If Forwards_OK is not set, the back end will need something
776 -- like memmove to handle the move. For now, this processing is
777 -- activated using the .s debug flag (-gnatd.s).
779 elsif Debug_Flag_Dot_S
then
784 -- At this stage we have to generate an explicit loop, and we have
785 -- the following cases:
787 -- Forwards_OK = True
789 -- Rnn : right_index := right_index'First;
790 -- for Lnn in left-index loop
791 -- left (Lnn) := right (Rnn);
792 -- Rnn := right_index'Succ (Rnn);
795 -- Note: the above code MUST be analyzed with checks off, because
796 -- otherwise the Succ could overflow. But in any case this is more
799 -- Forwards_OK = False, Backwards_OK = True
801 -- Rnn : right_index := right_index'Last;
802 -- for Lnn in reverse left-index loop
803 -- left (Lnn) := right (Rnn);
804 -- Rnn := right_index'Pred (Rnn);
807 -- Note: the above code MUST be analyzed with checks off, because
808 -- otherwise the Pred could overflow. But in any case this is more
811 -- Forwards_OK = Backwards_OK = False
813 -- This only happens if we have the same array on each side. It is
814 -- possible to create situations using overlays that violate this,
815 -- but we simply do not promise to get this "right" in this case.
817 -- There are two possible subcases. If the No_Implicit_Conditionals
818 -- restriction is set, then we generate the following code:
821 -- T : constant <operand-type> := rhs;
826 -- If implicit conditionals are permitted, then we generate:
828 -- if Left_Lo <= Right_Lo then
829 -- <code for Forwards_OK = True above>
831 -- <code for Backwards_OK = True above>
834 -- In order to detect possible aliasing, we examine the renamed
835 -- expression when the source or target is a renaming. However,
836 -- the renaming may be intended to capture an address that may be
837 -- affected by subsequent code, and therefore we must recover
838 -- the actual entity for the expansion that follows, not the
839 -- object it renames. In particular, if source or target designate
840 -- a portion of a dynamically allocated object, the pointer to it
841 -- may be reassigned but the renaming preserves the proper location.
843 if Is_Entity_Name
(Rhs
)
845 Nkind
(Parent
(Entity
(Rhs
))) = N_Object_Renaming_Declaration
846 and then Nkind
(Act_Rhs
) = N_Slice
851 if Is_Entity_Name
(Lhs
)
853 Nkind
(Parent
(Entity
(Lhs
))) = N_Object_Renaming_Declaration
854 and then Nkind
(Act_Lhs
) = N_Slice
859 -- Cases where either Forwards_OK or Backwards_OK is true
861 if Forwards_OK
(N
) or else Backwards_OK
(N
) then
862 if Needs_Finalization
(Component_Type
(L_Type
))
863 and then Base_Type
(L_Type
) = Base_Type
(R_Type
)
865 and then not No_Ctrl_Actions
(N
)
868 Proc
: constant Entity_Id
:=
869 TSS
(Base_Type
(L_Type
), TSS_Slice_Assign
);
873 Apply_Dereference
(Larray
);
874 Apply_Dereference
(Rarray
);
875 Actuals
:= New_List
(
876 Duplicate_Subexpr
(Larray
, Name_Req
=> True),
877 Duplicate_Subexpr
(Rarray
, Name_Req
=> True),
878 Duplicate_Subexpr
(Left_Lo
, Name_Req
=> True),
879 Duplicate_Subexpr
(Left_Hi
, Name_Req
=> True),
880 Duplicate_Subexpr
(Right_Lo
, Name_Req
=> True),
881 Duplicate_Subexpr
(Right_Hi
, Name_Req
=> True));
885 Boolean_Literals
(not Forwards_OK
(N
)), Loc
));
888 Make_Procedure_Call_Statement
(Loc
,
889 Name
=> New_Occurrence_Of
(Proc
, Loc
),
890 Parameter_Associations
=> Actuals
));
895 Expand_Assign_Array_Loop
896 (N
, Larray
, Rarray
, L_Type
, R_Type
, Ndim
,
897 Rev
=> not Forwards_OK
(N
)));
900 -- Case of both are false with No_Implicit_Conditionals
902 elsif Restriction_Active
(No_Implicit_Conditionals
) then
904 T
: constant Entity_Id
:=
905 Make_Defining_Identifier
(Loc
, Chars
=> Name_T
);
909 Make_Block_Statement
(Loc
,
910 Declarations
=> New_List
(
911 Make_Object_Declaration
(Loc
,
912 Defining_Identifier
=> T
,
913 Constant_Present
=> True,
915 New_Occurrence_Of
(Etype
(Rhs
), Loc
),
916 Expression
=> Relocate_Node
(Rhs
))),
918 Handled_Statement_Sequence
=>
919 Make_Handled_Sequence_Of_Statements
(Loc
,
920 Statements
=> New_List
(
921 Make_Assignment_Statement
(Loc
,
922 Name
=> Relocate_Node
(Lhs
),
923 Expression
=> New_Occurrence_Of
(T
, Loc
))))));
926 -- Case of both are false with implicit conditionals allowed
929 -- Before we generate this code, we must ensure that the left and
930 -- right side array types are defined. They may be itypes, and we
931 -- cannot let them be defined inside the if, since the first use
932 -- in the then may not be executed.
934 Ensure_Defined
(L_Type
, N
);
935 Ensure_Defined
(R_Type
, N
);
937 -- We normally compare addresses to find out which way round to
938 -- do the loop, since this is reliable, and handles the cases of
939 -- parameters, conversions etc. But we can't do that in the bit
940 -- packed case or the VM case, because addresses don't work there.
942 if not Is_Bit_Packed_Array
(L_Type
) and then VM_Target
= No_VM
then
946 Unchecked_Convert_To
(RTE
(RE_Integer_Address
),
947 Make_Attribute_Reference
(Loc
,
949 Make_Indexed_Component
(Loc
,
951 Duplicate_Subexpr_Move_Checks
(Larray
, True),
952 Expressions
=> New_List
(
953 Make_Attribute_Reference
(Loc
,
957 Attribute_Name
=> Name_First
))),
958 Attribute_Name
=> Name_Address
)),
961 Unchecked_Convert_To
(RTE
(RE_Integer_Address
),
962 Make_Attribute_Reference
(Loc
,
964 Make_Indexed_Component
(Loc
,
966 Duplicate_Subexpr_Move_Checks
(Rarray
, True),
967 Expressions
=> New_List
(
968 Make_Attribute_Reference
(Loc
,
972 Attribute_Name
=> Name_First
))),
973 Attribute_Name
=> Name_Address
)));
975 -- For the bit packed and VM cases we use the bounds. That's OK,
976 -- because we don't have to worry about parameters, since they
977 -- cannot cause overlap. Perhaps we should worry about weird slice
983 Cleft_Lo
:= New_Copy_Tree
(Left_Lo
);
984 Cright_Lo
:= New_Copy_Tree
(Right_Lo
);
986 -- If the types do not match we add an implicit conversion
987 -- here to ensure proper match
989 if Etype
(Left_Lo
) /= Etype
(Right_Lo
) then
991 Unchecked_Convert_To
(Etype
(Left_Lo
), Cright_Lo
);
994 -- Reset the Analyzed flag, because the bounds of the index
995 -- type itself may be universal, and must must be reanalyzed
996 -- to acquire the proper type for the back end.
998 Set_Analyzed
(Cleft_Lo
, False);
999 Set_Analyzed
(Cright_Lo
, False);
1003 Left_Opnd
=> Cleft_Lo
,
1004 Right_Opnd
=> Cright_Lo
);
1007 if Needs_Finalization
(Component_Type
(L_Type
))
1008 and then Base_Type
(L_Type
) = Base_Type
(R_Type
)
1010 and then not No_Ctrl_Actions
(N
)
1013 -- Call TSS procedure for array assignment, passing the
1014 -- explicit bounds of right and left hand sides.
1017 Proc
: constant Entity_Id
:=
1018 TSS
(Base_Type
(L_Type
), TSS_Slice_Assign
);
1022 Apply_Dereference
(Larray
);
1023 Apply_Dereference
(Rarray
);
1024 Actuals
:= New_List
(
1025 Duplicate_Subexpr
(Larray
, Name_Req
=> True),
1026 Duplicate_Subexpr
(Rarray
, Name_Req
=> True),
1027 Duplicate_Subexpr
(Left_Lo
, Name_Req
=> True),
1028 Duplicate_Subexpr
(Left_Hi
, Name_Req
=> True),
1029 Duplicate_Subexpr
(Right_Lo
, Name_Req
=> True),
1030 Duplicate_Subexpr
(Right_Hi
, Name_Req
=> True));
1034 Right_Opnd
=> Condition
));
1037 Make_Procedure_Call_Statement
(Loc
,
1038 Name
=> New_Occurrence_Of
(Proc
, Loc
),
1039 Parameter_Associations
=> Actuals
));
1044 Make_Implicit_If_Statement
(N
,
1045 Condition
=> Condition
,
1047 Then_Statements
=> New_List
(
1048 Expand_Assign_Array_Loop
1049 (N
, Larray
, Rarray
, L_Type
, R_Type
, Ndim
,
1052 Else_Statements
=> New_List
(
1053 Expand_Assign_Array_Loop
1054 (N
, Larray
, Rarray
, L_Type
, R_Type
, Ndim
,
1059 Analyze
(N
, Suppress
=> All_Checks
);
1063 when RE_Not_Available
=>
1065 end Expand_Assign_Array
;
1067 ------------------------------
1068 -- Expand_Assign_Array_Loop --
1069 ------------------------------
1071 -- The following is an example of the loop generated for the case of a
1072 -- two-dimensional array:
1075 -- R2b : Tm1X1 := 1;
1077 -- for L1b in 1 .. 100 loop
1079 -- R4b : Tm1X2 := 1;
1081 -- for L3b in 1 .. 100 loop
1082 -- vm1 (L1b, L3b) := vm2 (R2b, R4b);
1083 -- R4b := Tm1X2'succ(R4b);
1086 -- R2b := Tm1X1'succ(R2b);
1090 -- Here Rev is False, and Tm1Xn are the subscript types for the right hand
1091 -- side. The declarations of R2b and R4b are inserted before the original
1092 -- assignment statement.
1094 function Expand_Assign_Array_Loop
1101 Rev
: Boolean) return Node_Id
1103 Loc
: constant Source_Ptr
:= Sloc
(N
);
1105 Lnn
: array (1 .. Ndim
) of Entity_Id
;
1106 Rnn
: array (1 .. Ndim
) of Entity_Id
;
1107 -- Entities used as subscripts on left and right sides
1109 L_Index_Type
: array (1 .. Ndim
) of Entity_Id
;
1110 R_Index_Type
: array (1 .. Ndim
) of Entity_Id
;
1111 -- Left and right index types
1118 function Build_Step
(J
: Nat
) return Node_Id
;
1119 -- The increment step for the index of the right-hand side is written
1120 -- as an attribute reference (Succ or Pred). This function returns
1121 -- the corresponding node, which is placed at the end of the loop body.
1127 function Build_Step
(J
: Nat
) return Node_Id
is
1139 Make_Assignment_Statement
(Loc
,
1140 Name
=> New_Occurrence_Of
(Rnn
(J
), Loc
),
1142 Make_Attribute_Reference
(Loc
,
1144 New_Occurrence_Of
(R_Index_Type
(J
), Loc
),
1145 Attribute_Name
=> S_Or_P
,
1146 Expressions
=> New_List
(
1147 New_Occurrence_Of
(Rnn
(J
), Loc
))));
1149 -- Note that on the last iteration of the loop, the index is increased
1150 -- (or decreased) past the corresponding bound. This is consistent with
1151 -- the C semantics of the back-end, where such an off-by-one value on a
1152 -- dead index variable is OK. However, in CodePeer mode this leads to
1153 -- spurious warnings, and thus we place a guard around the attribute
1154 -- reference. For obvious reasons we only do this for CodePeer.
1156 if CodePeer_Mode
then
1158 Make_If_Statement
(Loc
,
1161 Left_Opnd
=> New_Occurrence_Of
(Lnn
(J
), Loc
),
1163 Make_Attribute_Reference
(Loc
,
1164 Prefix
=> New_Occurrence_Of
(L_Index_Type
(J
), Loc
),
1165 Attribute_Name
=> Lim
)),
1166 Then_Statements
=> New_List
(Step
));
1172 -- Start of processing for Expand_Assign_Array_Loop
1176 F_Or_L
:= Name_Last
;
1177 S_Or_P
:= Name_Pred
;
1179 F_Or_L
:= Name_First
;
1180 S_Or_P
:= Name_Succ
;
1183 -- Setup index types and subscript entities
1190 L_Index
:= First_Index
(L_Type
);
1191 R_Index
:= First_Index
(R_Type
);
1193 for J
in 1 .. Ndim
loop
1194 Lnn
(J
) := Make_Temporary
(Loc
, 'L');
1195 Rnn
(J
) := Make_Temporary
(Loc
, 'R');
1197 L_Index_Type
(J
) := Etype
(L_Index
);
1198 R_Index_Type
(J
) := Etype
(R_Index
);
1200 Next_Index
(L_Index
);
1201 Next_Index
(R_Index
);
1205 -- Now construct the assignment statement
1208 ExprL
: constant List_Id
:= New_List
;
1209 ExprR
: constant List_Id
:= New_List
;
1212 for J
in 1 .. Ndim
loop
1213 Append_To
(ExprL
, New_Occurrence_Of
(Lnn
(J
), Loc
));
1214 Append_To
(ExprR
, New_Occurrence_Of
(Rnn
(J
), Loc
));
1218 Make_Assignment_Statement
(Loc
,
1220 Make_Indexed_Component
(Loc
,
1221 Prefix
=> Duplicate_Subexpr
(Larray
, Name_Req
=> True),
1222 Expressions
=> ExprL
),
1224 Make_Indexed_Component
(Loc
,
1225 Prefix
=> Duplicate_Subexpr
(Rarray
, Name_Req
=> True),
1226 Expressions
=> ExprR
));
1228 -- We set assignment OK, since there are some cases, e.g. in object
1229 -- declarations, where we are actually assigning into a constant.
1230 -- If there really is an illegality, it was caught long before now,
1231 -- and was flagged when the original assignment was analyzed.
1233 Set_Assignment_OK
(Name
(Assign
));
1235 -- Propagate the No_Ctrl_Actions flag to individual assignments
1237 Set_No_Ctrl_Actions
(Assign
, No_Ctrl_Actions
(N
));
1240 -- Now construct the loop from the inside out, with the last subscript
1241 -- varying most rapidly. Note that Assign is first the raw assignment
1242 -- statement, and then subsequently the loop that wraps it up.
1244 for J
in reverse 1 .. Ndim
loop
1246 Make_Block_Statement
(Loc
,
1247 Declarations
=> New_List
(
1248 Make_Object_Declaration
(Loc
,
1249 Defining_Identifier
=> Rnn
(J
),
1250 Object_Definition
=>
1251 New_Occurrence_Of
(R_Index_Type
(J
), Loc
),
1253 Make_Attribute_Reference
(Loc
,
1254 Prefix
=> New_Occurrence_Of
(R_Index_Type
(J
), Loc
),
1255 Attribute_Name
=> F_Or_L
))),
1257 Handled_Statement_Sequence
=>
1258 Make_Handled_Sequence_Of_Statements
(Loc
,
1259 Statements
=> New_List
(
1260 Make_Implicit_Loop_Statement
(N
,
1262 Make_Iteration_Scheme
(Loc
,
1263 Loop_Parameter_Specification
=>
1264 Make_Loop_Parameter_Specification
(Loc
,
1265 Defining_Identifier
=> Lnn
(J
),
1266 Reverse_Present
=> Rev
,
1267 Discrete_Subtype_Definition
=>
1268 New_Occurrence_Of
(L_Index_Type
(J
), Loc
))),
1270 Statements
=> New_List
(Assign
, Build_Step
(J
))))));
1274 end Expand_Assign_Array_Loop
;
1276 --------------------------
1277 -- Expand_Assign_Record --
1278 --------------------------
1280 procedure Expand_Assign_Record
(N
: Node_Id
) is
1281 Lhs
: constant Node_Id
:= Name
(N
);
1282 Rhs
: Node_Id
:= Expression
(N
);
1283 L_Typ
: constant Entity_Id
:= Base_Type
(Etype
(Lhs
));
1286 -- If change of representation, then extract the real right hand side
1287 -- from the type conversion, and proceed with component-wise assignment,
1288 -- since the two types are not the same as far as the back end is
1291 if Change_Of_Representation
(N
) then
1292 Rhs
:= Expression
(Rhs
);
1294 -- If this may be a case of a large bit aligned component, then proceed
1295 -- with component-wise assignment, to avoid possible clobbering of other
1296 -- components sharing bits in the first or last byte of the component to
1299 elsif Possible_Bit_Aligned_Component
(Lhs
)
1301 Possible_Bit_Aligned_Component
(Rhs
)
1305 -- If we have a tagged type that has a complete record representation
1306 -- clause, we must do we must do component-wise assignments, since child
1307 -- types may have used gaps for their components, and we might be
1308 -- dealing with a view conversion.
1310 elsif Is_Fully_Repped_Tagged_Type
(L_Typ
) then
1313 -- If neither condition met, then nothing special to do, the back end
1314 -- can handle assignment of the entire component as a single entity.
1320 -- At this stage we know that we must do a component wise assignment
1323 Loc
: constant Source_Ptr
:= Sloc
(N
);
1324 R_Typ
: constant Entity_Id
:= Base_Type
(Etype
(Rhs
));
1325 Decl
: constant Node_Id
:= Declaration_Node
(R_Typ
);
1329 function Find_Component
1331 Comp
: Entity_Id
) return Entity_Id
;
1332 -- Find the component with the given name in the underlying record
1333 -- declaration for Typ. We need to use the actual entity because the
1334 -- type may be private and resolution by identifier alone would fail.
1336 function Make_Component_List_Assign
1338 U_U
: Boolean := False) return List_Id
;
1339 -- Returns a sequence of statements to assign the components that
1340 -- are referenced in the given component list. The flag U_U is
1341 -- used to force the usage of the inferred value of the variant
1342 -- part expression as the switch for the generated case statement.
1344 function Make_Field_Assign
1346 U_U
: Boolean := False) return Node_Id
;
1347 -- Given C, the entity for a discriminant or component, build an
1348 -- assignment for the corresponding field values. The flag U_U
1349 -- signals the presence of an Unchecked_Union and forces the usage
1350 -- of the inferred discriminant value of C as the right hand side
1351 -- of the assignment.
1353 function Make_Field_Assigns
(CI
: List_Id
) return List_Id
;
1354 -- Given CI, a component items list, construct series of statements
1355 -- for fieldwise assignment of the corresponding components.
1357 --------------------
1358 -- Find_Component --
1359 --------------------
1361 function Find_Component
1363 Comp
: Entity_Id
) return Entity_Id
1365 Utyp
: constant Entity_Id
:= Underlying_Type
(Typ
);
1369 C
:= First_Entity
(Utyp
);
1370 while Present
(C
) loop
1371 if Chars
(C
) = Chars
(Comp
) then
1378 raise Program_Error
;
1381 --------------------------------
1382 -- Make_Component_List_Assign --
1383 --------------------------------
1385 function Make_Component_List_Assign
1387 U_U
: Boolean := False) return List_Id
1389 CI
: constant List_Id
:= Component_Items
(CL
);
1390 VP
: constant Node_Id
:= Variant_Part
(CL
);
1400 Result
:= Make_Field_Assigns
(CI
);
1402 if Present
(VP
) then
1403 V
:= First_Non_Pragma
(Variants
(VP
));
1405 while Present
(V
) loop
1407 DC
:= First
(Discrete_Choices
(V
));
1408 while Present
(DC
) loop
1409 Append_To
(DCH
, New_Copy_Tree
(DC
));
1414 Make_Case_Statement_Alternative
(Loc
,
1415 Discrete_Choices
=> DCH
,
1417 Make_Component_List_Assign
(Component_List
(V
))));
1418 Next_Non_Pragma
(V
);
1421 -- If we have an Unchecked_Union, use the value of the inferred
1422 -- discriminant of the variant part expression as the switch
1423 -- for the case statement. The case statement may later be
1428 New_Copy
(Get_Discriminant_Value
(
1431 Discriminant_Constraint
(Etype
(Rhs
))));
1434 Make_Selected_Component
(Loc
,
1435 Prefix
=> Duplicate_Subexpr
(Rhs
),
1437 Make_Identifier
(Loc
, Chars
(Name
(VP
))));
1441 Make_Case_Statement
(Loc
,
1443 Alternatives
=> Alts
));
1447 end Make_Component_List_Assign
;
1449 -----------------------
1450 -- Make_Field_Assign --
1451 -----------------------
1453 function Make_Field_Assign
1455 U_U
: Boolean := False) return Node_Id
1461 -- In the case of an Unchecked_Union, use the discriminant
1462 -- constraint value as on the right hand side of the assignment.
1466 New_Copy
(Get_Discriminant_Value
(C
,
1468 Discriminant_Constraint
(Etype
(Rhs
))));
1471 Make_Selected_Component
(Loc
,
1472 Prefix
=> Duplicate_Subexpr
(Rhs
),
1473 Selector_Name
=> New_Occurrence_Of
(C
, Loc
));
1477 Make_Assignment_Statement
(Loc
,
1479 Make_Selected_Component
(Loc
,
1480 Prefix
=> Duplicate_Subexpr
(Lhs
),
1482 New_Occurrence_Of
(Find_Component
(L_Typ
, C
), Loc
)),
1483 Expression
=> Expr
);
1485 -- Set Assignment_OK, so discriminants can be assigned
1487 Set_Assignment_OK
(Name
(A
), True);
1489 if Componentwise_Assignment
(N
)
1490 and then Nkind
(Name
(A
)) = N_Selected_Component
1491 and then Chars
(Selector_Name
(Name
(A
))) = Name_uParent
1493 Set_Componentwise_Assignment
(A
);
1497 end Make_Field_Assign
;
1499 ------------------------
1500 -- Make_Field_Assigns --
1501 ------------------------
1503 function Make_Field_Assigns
(CI
: List_Id
) return List_Id
is
1511 while Present
(Item
) loop
1513 -- Look for components, but exclude _tag field assignment if
1514 -- the special Componentwise_Assignment flag is set.
1516 if Nkind
(Item
) = N_Component_Declaration
1517 and then not (Is_Tag
(Defining_Identifier
(Item
))
1518 and then Componentwise_Assignment
(N
))
1521 (Result
, Make_Field_Assign
(Defining_Identifier
(Item
)));
1528 end Make_Field_Assigns
;
1530 -- Start of processing for Expand_Assign_Record
1533 -- Note that we use the base types for this processing. This results
1534 -- in some extra work in the constrained case, but the change of
1535 -- representation case is so unusual that it is not worth the effort.
1537 -- First copy the discriminants. This is done unconditionally. It
1538 -- is required in the unconstrained left side case, and also in the
1539 -- case where this assignment was constructed during the expansion
1540 -- of a type conversion (since initialization of discriminants is
1541 -- suppressed in this case). It is unnecessary but harmless in
1544 if Has_Discriminants
(L_Typ
) then
1545 F
:= First_Discriminant
(R_Typ
);
1546 while Present
(F
) loop
1548 -- If we are expanding the initialization of a derived record
1549 -- that constrains or renames discriminants of the parent, we
1550 -- must use the corresponding discriminant in the parent.
1557 and then Present
(Corresponding_Discriminant
(F
))
1559 CF
:= Corresponding_Discriminant
(F
);
1564 if Is_Unchecked_Union
(Base_Type
(R_Typ
)) then
1566 -- Within an initialization procedure this is the
1567 -- assignment to an unchecked union component, in which
1568 -- case there is no discriminant to initialize.
1570 if Inside_Init_Proc
then
1574 -- The assignment is part of a conversion from a
1575 -- derived unchecked union type with an inferable
1576 -- discriminant, to a parent type.
1578 Insert_Action
(N
, Make_Field_Assign
(CF
, True));
1582 Insert_Action
(N
, Make_Field_Assign
(CF
));
1585 Next_Discriminant
(F
);
1590 -- We know the underlying type is a record, but its current view
1591 -- may be private. We must retrieve the usable record declaration.
1593 if Nkind_In
(Decl
, N_Private_Type_Declaration
,
1594 N_Private_Extension_Declaration
)
1595 and then Present
(Full_View
(R_Typ
))
1597 RDef
:= Type_Definition
(Declaration_Node
(Full_View
(R_Typ
)));
1599 RDef
:= Type_Definition
(Decl
);
1602 if Nkind
(RDef
) = N_Derived_Type_Definition
then
1603 RDef
:= Record_Extension_Part
(RDef
);
1606 if Nkind
(RDef
) = N_Record_Definition
1607 and then Present
(Component_List
(RDef
))
1609 if Is_Unchecked_Union
(R_Typ
) then
1611 Make_Component_List_Assign
(Component_List
(RDef
), True));
1614 (N
, Make_Component_List_Assign
(Component_List
(RDef
)));
1617 Rewrite
(N
, Make_Null_Statement
(Loc
));
1620 end Expand_Assign_Record
;
1622 -----------------------------------
1623 -- Expand_N_Assignment_Statement --
1624 -----------------------------------
1626 -- This procedure implements various cases where an assignment statement
1627 -- cannot just be passed on to the back end in untransformed state.
1629 procedure Expand_N_Assignment_Statement
(N
: Node_Id
) is
1630 GM
: constant Ghost_Mode_Type
:= Ghost_Mode
;
1632 procedure Restore_Globals
;
1633 -- Restore the values of all saved global variables
1635 ---------------------
1636 -- Restore_Globals --
1637 ---------------------
1639 procedure Restore_Globals
is
1642 end Restore_Globals
;
1646 Crep
: constant Boolean := Change_Of_Representation
(N
);
1647 Lhs
: constant Node_Id
:= Name
(N
);
1648 Loc
: constant Source_Ptr
:= Sloc
(N
);
1649 Rhs
: constant Node_Id
:= Expression
(N
);
1650 Typ
: constant Entity_Id
:= Underlying_Type
(Etype
(Lhs
));
1653 -- Start of processing for Expand_N_Assignment_Statement
1656 -- The assignment statement may be Ghost if the left hand side is Ghost.
1657 -- Set the mode now to ensure that any nodes generated during expansion
1658 -- are properly flagged as ignored Ghost.
1662 -- Special case to check right away, if the Componentwise_Assignment
1663 -- flag is set, this is a reanalysis from the expansion of the primitive
1664 -- assignment procedure for a tagged type, and all we need to do is to
1665 -- expand to assignment of components, because otherwise, we would get
1666 -- infinite recursion (since this looks like a tagged assignment which
1667 -- would normally try to *call* the primitive assignment procedure).
1669 if Componentwise_Assignment
(N
) then
1670 Expand_Assign_Record
(N
);
1675 -- Defend against invalid subscripts on left side if we are in standard
1676 -- validity checking mode. No need to do this if we are checking all
1679 -- Note that we do this right away, because there are some early return
1680 -- paths in this procedure, and this is required on all paths.
1682 if Validity_Checks_On
1683 and then Validity_Check_Default
1684 and then not Validity_Check_Subscripts
1686 Check_Valid_Lvalue_Subscripts
(Lhs
);
1689 -- Ada 2005 (AI-327): Handle assignment to priority of protected object
1691 -- Rewrite an assignment to X'Priority into a run-time call
1693 -- For example: X'Priority := New_Prio_Expr;
1694 -- ...is expanded into Set_Ceiling (X._Object, New_Prio_Expr);
1696 -- Note that although X'Priority is notionally an object, it is quite
1697 -- deliberately not defined as an aliased object in the RM. This means
1698 -- that it works fine to rewrite it as a call, without having to worry
1699 -- about complications that would other arise from X'Priority'Access,
1700 -- which is illegal, because of the lack of aliasing.
1702 if Ada_Version
>= Ada_2005
then
1705 Conctyp
: Entity_Id
;
1708 RT_Subprg_Name
: Node_Id
;
1711 -- Handle chains of renamings
1714 while Nkind
(Ent
) in N_Has_Entity
1715 and then Present
(Entity
(Ent
))
1716 and then Present
(Renamed_Object
(Entity
(Ent
)))
1718 Ent
:= Renamed_Object
(Entity
(Ent
));
1721 -- The attribute Priority applied to protected objects has been
1722 -- previously expanded into a call to the Get_Ceiling run-time
1725 if Nkind
(Ent
) = N_Function_Call
1726 and then (Entity
(Name
(Ent
)) = RTE
(RE_Get_Ceiling
)
1728 Entity
(Name
(Ent
)) = RTE
(RO_PE_Get_Ceiling
))
1730 -- Look for the enclosing concurrent type
1732 Conctyp
:= Current_Scope
;
1733 while not Is_Concurrent_Type
(Conctyp
) loop
1734 Conctyp
:= Scope
(Conctyp
);
1737 pragma Assert
(Is_Protected_Type
(Conctyp
));
1739 -- Generate the first actual of the call
1741 Subprg
:= Current_Scope
;
1742 while not Present
(Protected_Body_Subprogram
(Subprg
)) loop
1743 Subprg
:= Scope
(Subprg
);
1746 -- Select the appropriate run-time call
1748 if Number_Entries
(Conctyp
) = 0 then
1750 New_Occurrence_Of
(RTE
(RE_Set_Ceiling
), Loc
);
1753 New_Occurrence_Of
(RTE
(RO_PE_Set_Ceiling
), Loc
);
1757 Make_Procedure_Call_Statement
(Loc
,
1758 Name
=> RT_Subprg_Name
,
1759 Parameter_Associations
=> New_List
(
1760 New_Copy_Tree
(First
(Parameter_Associations
(Ent
))),
1761 Relocate_Node
(Expression
(N
))));
1772 -- Deal with assignment checks unless suppressed
1774 if not Suppress_Assignment_Checks
(N
) then
1776 -- First deal with generation of range check if required
1778 if Do_Range_Check
(Rhs
) then
1779 Generate_Range_Check
(Rhs
, Typ
, CE_Range_Check_Failed
);
1782 -- Then generate predicate check if required
1784 Apply_Predicate_Check
(Rhs
, Typ
);
1787 -- Check for a special case where a high level transformation is
1788 -- required. If we have either of:
1793 -- where P is a reference to a bit packed array, then we have to unwind
1794 -- the assignment. The exact meaning of being a reference to a bit
1795 -- packed array is as follows:
1797 -- An indexed component whose prefix is a bit packed array is a
1798 -- reference to a bit packed array.
1800 -- An indexed component or selected component whose prefix is a
1801 -- reference to a bit packed array is itself a reference ot a
1802 -- bit packed array.
1804 -- The required transformation is
1806 -- Tnn : prefix_type := P;
1807 -- Tnn.field := rhs;
1812 -- Tnn : prefix_type := P;
1813 -- Tnn (subscr) := rhs;
1816 -- Since P is going to be evaluated more than once, any subscripts
1817 -- in P must have their evaluation forced.
1819 if Nkind_In
(Lhs
, N_Indexed_Component
, N_Selected_Component
)
1820 and then Is_Ref_To_Bit_Packed_Array
(Prefix
(Lhs
))
1823 BPAR_Expr
: constant Node_Id
:= Relocate_Node
(Prefix
(Lhs
));
1824 BPAR_Typ
: constant Entity_Id
:= Etype
(BPAR_Expr
);
1825 Tnn
: constant Entity_Id
:=
1826 Make_Temporary
(Loc
, 'T', BPAR_Expr
);
1829 -- Insert the post assignment first, because we want to copy the
1830 -- BPAR_Expr tree before it gets analyzed in the context of the
1831 -- pre assignment. Note that we do not analyze the post assignment
1832 -- yet (we cannot till we have completed the analysis of the pre
1833 -- assignment). As usual, the analysis of this post assignment
1834 -- will happen on its own when we "run into" it after finishing
1835 -- the current assignment.
1838 Make_Assignment_Statement
(Loc
,
1839 Name
=> New_Copy_Tree
(BPAR_Expr
),
1840 Expression
=> New_Occurrence_Of
(Tnn
, Loc
)));
1842 -- At this stage BPAR_Expr is a reference to a bit packed array
1843 -- where the reference was not expanded in the original tree,
1844 -- since it was on the left side of an assignment. But in the
1845 -- pre-assignment statement (the object definition), BPAR_Expr
1846 -- will end up on the right hand side, and must be reexpanded. To
1847 -- achieve this, we reset the analyzed flag of all selected and
1848 -- indexed components down to the actual indexed component for
1849 -- the packed array.
1853 Set_Analyzed
(Exp
, False);
1856 (Exp
, N_Selected_Component
, N_Indexed_Component
)
1858 Exp
:= Prefix
(Exp
);
1864 -- Now we can insert and analyze the pre-assignment
1866 -- If the right-hand side requires a transient scope, it has
1867 -- already been placed on the stack. However, the declaration is
1868 -- inserted in the tree outside of this scope, and must reflect
1869 -- the proper scope for its variable. This awkward bit is forced
1870 -- by the stricter scope discipline imposed by GCC 2.97.
1873 Uses_Transient_Scope
: constant Boolean :=
1875 and then N
= Node_To_Be_Wrapped
;
1878 if Uses_Transient_Scope
then
1879 Push_Scope
(Scope
(Current_Scope
));
1882 Insert_Before_And_Analyze
(N
,
1883 Make_Object_Declaration
(Loc
,
1884 Defining_Identifier
=> Tnn
,
1885 Object_Definition
=> New_Occurrence_Of
(BPAR_Typ
, Loc
),
1886 Expression
=> BPAR_Expr
));
1888 if Uses_Transient_Scope
then
1893 -- Now fix up the original assignment and continue processing
1895 Rewrite
(Prefix
(Lhs
),
1896 New_Occurrence_Of
(Tnn
, Loc
));
1898 -- We do not need to reanalyze that assignment, and we do not need
1899 -- to worry about references to the temporary, but we do need to
1900 -- make sure that the temporary is not marked as a true constant
1901 -- since we now have a generated assignment to it.
1903 Set_Is_True_Constant
(Tnn
, False);
1907 -- When we have the appropriate type of aggregate in the expression (it
1908 -- has been determined during analysis of the aggregate by setting the
1909 -- delay flag), let's perform in place assignment and thus avoid
1910 -- creating a temporary.
1912 if Is_Delayed_Aggregate
(Rhs
) then
1913 Convert_Aggr_In_Assignment
(N
);
1914 Rewrite
(N
, Make_Null_Statement
(Loc
));
1921 -- Apply discriminant check if required. If Lhs is an access type to a
1922 -- designated type with discriminants, we must always check. If the
1923 -- type has unknown discriminants, more elaborate processing below.
1925 if Has_Discriminants
(Etype
(Lhs
))
1926 and then not Has_Unknown_Discriminants
(Etype
(Lhs
))
1928 -- Skip discriminant check if change of representation. Will be
1929 -- done when the change of representation is expanded out.
1932 Apply_Discriminant_Check
(Rhs
, Etype
(Lhs
), Lhs
);
1935 -- If the type is private without discriminants, and the full type
1936 -- has discriminants (necessarily with defaults) a check may still be
1937 -- necessary if the Lhs is aliased. The private discriminants must be
1938 -- visible to build the discriminant constraints.
1940 -- Only an explicit dereference that comes from source indicates
1941 -- aliasing. Access to formals of protected operations and entries
1942 -- create dereferences but are not semantic aliasings.
1944 elsif Is_Private_Type
(Etype
(Lhs
))
1945 and then Has_Discriminants
(Typ
)
1946 and then Nkind
(Lhs
) = N_Explicit_Dereference
1947 and then Comes_From_Source
(Lhs
)
1950 Lt
: constant Entity_Id
:= Etype
(Lhs
);
1951 Ubt
: Entity_Id
:= Base_Type
(Typ
);
1954 -- In the case of an expander-generated record subtype whose base
1955 -- type still appears private, Typ will have been set to that
1956 -- private type rather than the underlying record type (because
1957 -- Underlying type will have returned the record subtype), so it's
1958 -- necessary to apply Underlying_Type again to the base type to
1959 -- get the record type we need for the discriminant check. Such
1960 -- subtypes can be created for assignments in certain cases, such
1961 -- as within an instantiation passed this kind of private type.
1962 -- It would be good to avoid this special test, but making changes
1963 -- to prevent this odd form of record subtype seems difficult. ???
1965 if Is_Private_Type
(Ubt
) then
1966 Ubt
:= Underlying_Type
(Ubt
);
1969 Set_Etype
(Lhs
, Ubt
);
1970 Rewrite
(Rhs
, OK_Convert_To
(Base_Type
(Ubt
), Rhs
));
1971 Apply_Discriminant_Check
(Rhs
, Ubt
, Lhs
);
1972 Set_Etype
(Lhs
, Lt
);
1975 -- If the Lhs has a private type with unknown discriminants, it may
1976 -- have a full view with discriminants, but those are nameable only
1977 -- in the underlying type, so convert the Rhs to it before potential
1978 -- checking. Convert Lhs as well, otherwise the actual subtype might
1979 -- not be constructible.
1981 elsif Has_Unknown_Discriminants
(Base_Type
(Etype
(Lhs
)))
1982 and then Has_Discriminants
(Typ
)
1984 Rewrite
(Rhs
, OK_Convert_To
(Base_Type
(Typ
), Rhs
));
1985 Rewrite
(Lhs
, OK_Convert_To
(Base_Type
(Typ
), Lhs
));
1986 Apply_Discriminant_Check
(Rhs
, Typ
, Lhs
);
1988 -- In the access type case, we need the same discriminant check, and
1989 -- also range checks if we have an access to constrained array.
1991 elsif Is_Access_Type
(Etype
(Lhs
))
1992 and then Is_Constrained
(Designated_Type
(Etype
(Lhs
)))
1994 if Has_Discriminants
(Designated_Type
(Etype
(Lhs
))) then
1996 -- Skip discriminant check if change of representation. Will be
1997 -- done when the change of representation is expanded out.
2000 Apply_Discriminant_Check
(Rhs
, Etype
(Lhs
));
2003 elsif Is_Array_Type
(Designated_Type
(Etype
(Lhs
))) then
2004 Apply_Range_Check
(Rhs
, Etype
(Lhs
));
2006 if Is_Constrained
(Etype
(Lhs
)) then
2007 Apply_Length_Check
(Rhs
, Etype
(Lhs
));
2010 if Nkind
(Rhs
) = N_Allocator
then
2012 Target_Typ
: constant Entity_Id
:= Etype
(Expression
(Rhs
));
2013 C_Es
: Check_Result
;
2020 Etype
(Designated_Type
(Etype
(Lhs
))));
2032 -- Apply range check for access type case
2034 elsif Is_Access_Type
(Etype
(Lhs
))
2035 and then Nkind
(Rhs
) = N_Allocator
2036 and then Nkind
(Expression
(Rhs
)) = N_Qualified_Expression
2038 Analyze_And_Resolve
(Expression
(Rhs
));
2040 (Expression
(Rhs
), Designated_Type
(Etype
(Lhs
)));
2043 -- Ada 2005 (AI-231): Generate the run-time check
2045 if Is_Access_Type
(Typ
)
2046 and then Can_Never_Be_Null
(Etype
(Lhs
))
2047 and then not Can_Never_Be_Null
(Etype
(Rhs
))
2049 -- If an actual is an out parameter of a null-excluding access
2050 -- type, there is access check on entry, so we set the flag
2051 -- Suppress_Assignment_Checks on the generated statement to
2052 -- assign the actual to the parameter block, and we do not want
2053 -- to generate an additional check at this point.
2055 and then not Suppress_Assignment_Checks
(N
)
2057 Apply_Constraint_Check
(Rhs
, Etype
(Lhs
));
2060 -- Ada 2012 (AI05-148): Update current accessibility level if Rhs is a
2061 -- stand-alone obj of an anonymous access type.
2063 if Is_Access_Type
(Typ
)
2064 and then Is_Entity_Name
(Lhs
)
2065 and then Present
(Effective_Extra_Accessibility
(Entity
(Lhs
)))
2068 function Lhs_Entity
return Entity_Id
;
2069 -- Look through renames to find the underlying entity.
2070 -- For assignment to a rename, we don't care about the
2071 -- Enclosing_Dynamic_Scope of the rename declaration.
2077 function Lhs_Entity
return Entity_Id
is
2078 Result
: Entity_Id
:= Entity
(Lhs
);
2081 while Present
(Renamed_Object
(Result
)) loop
2083 -- Renamed_Object must return an Entity_Name here
2084 -- because of preceding "Present (E_E_A (...))" test.
2086 Result
:= Entity
(Renamed_Object
(Result
));
2092 -- Local Declarations
2094 Access_Check
: constant Node_Id
:=
2095 Make_Raise_Program_Error
(Loc
,
2099 Dynamic_Accessibility_Level
(Rhs
),
2101 Make_Integer_Literal
(Loc
,
2104 (Enclosing_Dynamic_Scope
2106 Reason
=> PE_Accessibility_Check_Failed
);
2108 Access_Level_Update
: constant Node_Id
:=
2109 Make_Assignment_Statement
(Loc
,
2112 (Effective_Extra_Accessibility
2113 (Entity
(Lhs
)), Loc
),
2115 Dynamic_Accessibility_Level
(Rhs
));
2118 if not Accessibility_Checks_Suppressed
(Entity
(Lhs
)) then
2119 Insert_Action
(N
, Access_Check
);
2122 Insert_Action
(N
, Access_Level_Update
);
2126 -- Case of assignment to a bit packed array element. If there is a
2127 -- change of representation this must be expanded into components,
2128 -- otherwise this is a bit-field assignment.
2130 if Nkind
(Lhs
) = N_Indexed_Component
2131 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Lhs
)))
2133 -- Normal case, no change of representation
2136 Expand_Bit_Packed_Element_Set
(N
);
2140 -- Change of representation case
2143 -- Generate the following, to force component-by-component
2144 -- assignments in an efficient way. Otherwise each component
2145 -- will require a temporary and two bit-field manipulations.
2152 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T');
2158 Make_Object_Declaration
(Loc
,
2159 Defining_Identifier
=> Tnn
,
2160 Object_Definition
=>
2161 New_Occurrence_Of
(Etype
(Lhs
), Loc
)),
2162 Make_Assignment_Statement
(Loc
,
2163 Name
=> New_Occurrence_Of
(Tnn
, Loc
),
2164 Expression
=> Relocate_Node
(Rhs
)),
2165 Make_Assignment_Statement
(Loc
,
2166 Name
=> Relocate_Node
(Lhs
),
2167 Expression
=> New_Occurrence_Of
(Tnn
, Loc
)));
2169 Insert_Actions
(N
, Stats
);
2170 Rewrite
(N
, Make_Null_Statement
(Loc
));
2175 -- Build-in-place function call case. Note that we're not yet doing
2176 -- build-in-place for user-written assignment statements (the assignment
2177 -- here came from an aggregate.)
2179 elsif Ada_Version
>= Ada_2005
2180 and then Is_Build_In_Place_Function_Call
(Rhs
)
2182 Make_Build_In_Place_Call_In_Assignment
(N
, Rhs
);
2184 elsif Is_Tagged_Type
(Typ
) and then Is_Value_Type
(Etype
(Lhs
)) then
2186 -- Nothing to do for valuetypes
2187 -- ??? Set_Scope_Is_Transient (False);
2192 elsif Is_Tagged_Type
(Typ
)
2193 or else (Needs_Finalization
(Typ
) and then not Is_Array_Type
(Typ
))
2195 Tagged_Case
: declare
2196 L
: List_Id
:= No_List
;
2197 Expand_Ctrl_Actions
: constant Boolean := not No_Ctrl_Actions
(N
);
2200 -- In the controlled case, we ensure that function calls are
2201 -- evaluated before finalizing the target. In all cases, it makes
2202 -- the expansion easier if the side-effects are removed first.
2204 Remove_Side_Effects
(Lhs
);
2205 Remove_Side_Effects
(Rhs
);
2207 -- Avoid recursion in the mechanism
2211 -- If dispatching assignment, we need to dispatch to _assign
2213 if Is_Class_Wide_Type
(Typ
)
2215 -- If the type is tagged, we may as well use the predefined
2216 -- primitive assignment. This avoids inlining a lot of code
2217 -- and in the class-wide case, the assignment is replaced
2218 -- by a dispatching call to _assign. It is suppressed in the
2219 -- case of assignments created by the expander that correspond
2220 -- to initializations, where we do want to copy the tag
2221 -- (Expand_Ctrl_Actions flag is set False in this case). It is
2222 -- also suppressed if restriction No_Dispatching_Calls is in
2223 -- force because in that case predefined primitives are not
2226 or else (Is_Tagged_Type
(Typ
)
2227 and then not Is_Value_Type
(Etype
(Lhs
))
2228 and then Chars
(Current_Scope
) /= Name_uAssign
2229 and then Expand_Ctrl_Actions
2231 not Restriction_Active
(No_Dispatching_Calls
))
2233 if Is_Limited_Type
(Typ
) then
2235 -- This can happen in an instance when the formal is an
2236 -- extension of a limited interface, and the actual is
2237 -- limited. This is an error according to AI05-0087, but
2238 -- is not caught at the point of instantiation in earlier
2241 -- This is wrong, error messages cannot be issued during
2242 -- expansion, since they would be missed in -gnatc mode ???
2244 Error_Msg_N
("assignment not available on limited type", N
);
2249 -- Fetch the primitive op _assign and proper type to call it.
2250 -- Because of possible conflicts between private and full view,
2251 -- fetch the proper type directly from the operation profile.
2254 Op
: constant Entity_Id
:=
2255 Find_Prim_Op
(Typ
, Name_uAssign
);
2256 F_Typ
: Entity_Id
:= Etype
(First_Formal
(Op
));
2259 -- If the assignment is dispatching, make sure to use the
2262 if Is_Class_Wide_Type
(Typ
) then
2263 F_Typ
:= Class_Wide_Type
(F_Typ
);
2268 -- In case of assignment to a class-wide tagged type, before
2269 -- the assignment we generate run-time check to ensure that
2270 -- the tags of source and target match.
2272 if not Tag_Checks_Suppressed
(Typ
)
2273 and then Is_Class_Wide_Type
(Typ
)
2274 and then Is_Tagged_Type
(Typ
)
2275 and then Is_Tagged_Type
(Underlying_Type
(Etype
(Rhs
)))
2278 Make_Raise_Constraint_Error
(Loc
,
2282 Make_Selected_Component
(Loc
,
2283 Prefix
=> Duplicate_Subexpr
(Lhs
),
2285 Make_Identifier
(Loc
, Name_uTag
)),
2287 Make_Selected_Component
(Loc
,
2288 Prefix
=> Duplicate_Subexpr
(Rhs
),
2290 Make_Identifier
(Loc
, Name_uTag
))),
2291 Reason
=> CE_Tag_Check_Failed
));
2295 Left_N
: Node_Id
:= Duplicate_Subexpr
(Lhs
);
2296 Right_N
: Node_Id
:= Duplicate_Subexpr
(Rhs
);
2299 -- In order to dispatch the call to _assign the type of
2300 -- the actuals must match. Add conversion (if required).
2302 if Etype
(Lhs
) /= F_Typ
then
2303 Left_N
:= Unchecked_Convert_To
(F_Typ
, Left_N
);
2306 if Etype
(Rhs
) /= F_Typ
then
2307 Right_N
:= Unchecked_Convert_To
(F_Typ
, Right_N
);
2311 Make_Procedure_Call_Statement
(Loc
,
2312 Name
=> New_Occurrence_Of
(Op
, Loc
),
2313 Parameter_Associations
=> New_List
(
2315 Node2
=> Right_N
)));
2320 L
:= Make_Tag_Ctrl_Assignment
(N
);
2322 -- We can't afford to have destructive Finalization Actions in
2323 -- the Self assignment case, so if the target and the source
2324 -- are not obviously different, code is generated to avoid the
2325 -- self assignment case:
2327 -- if lhs'address /= rhs'address then
2328 -- <code for controlled and/or tagged assignment>
2331 -- Skip this if Restriction (No_Finalization) is active
2333 if not Statically_Different
(Lhs
, Rhs
)
2334 and then Expand_Ctrl_Actions
2335 and then not Restriction_Active
(No_Finalization
)
2338 Make_Implicit_If_Statement
(N
,
2342 Make_Attribute_Reference
(Loc
,
2343 Prefix
=> Duplicate_Subexpr
(Lhs
),
2344 Attribute_Name
=> Name_Address
),
2347 Make_Attribute_Reference
(Loc
,
2348 Prefix
=> Duplicate_Subexpr
(Rhs
),
2349 Attribute_Name
=> Name_Address
)),
2351 Then_Statements
=> L
));
2354 -- We need to set up an exception handler for implementing
2355 -- 7.6.1(18). The remaining adjustments are tackled by the
2356 -- implementation of adjust for record_controllers (see
2359 -- This is skipped if we have no finalization
2361 if Expand_Ctrl_Actions
2362 and then not Restriction_Active
(No_Finalization
)
2365 Make_Block_Statement
(Loc
,
2366 Handled_Statement_Sequence
=>
2367 Make_Handled_Sequence_Of_Statements
(Loc
,
2369 Exception_Handlers
=> New_List
(
2370 Make_Handler_For_Ctrl_Operation
(Loc
)))));
2375 Make_Block_Statement
(Loc
,
2376 Handled_Statement_Sequence
=>
2377 Make_Handled_Sequence_Of_Statements
(Loc
, Statements
=> L
)));
2379 -- If no restrictions on aborts, protect the whole assignment
2380 -- for controlled objects as per 9.8(11).
2382 if Needs_Finalization
(Typ
)
2383 and then Expand_Ctrl_Actions
2384 and then Abort_Allowed
2387 Blk
: constant Entity_Id
:=
2389 (E_Block
, Current_Scope
, Sloc
(N
), 'B');
2390 AUD
: constant Entity_Id
:= RTE
(RE_Abort_Undefer_Direct
);
2393 Set_Scope
(Blk
, Current_Scope
);
2394 Set_Etype
(Blk
, Standard_Void_Type
);
2395 Set_Identifier
(N
, New_Occurrence_Of
(Blk
, Sloc
(N
)));
2397 Prepend_To
(L
, Build_Runtime_Call
(Loc
, RE_Abort_Defer
));
2398 Set_At_End_Proc
(Handled_Statement_Sequence
(N
),
2399 New_Occurrence_Of
(AUD
, Loc
));
2401 -- Present the Abort_Undefer_Direct function to the backend
2402 -- so that it can inline the call to the function.
2404 Add_Inlined_Body
(AUD
, N
);
2406 Expand_At_End_Handler
2407 (Handled_Statement_Sequence
(N
), Blk
);
2411 -- N has been rewritten to a block statement for which it is
2412 -- known by construction that no checks are necessary: analyze
2413 -- it with all checks suppressed.
2415 Analyze
(N
, Suppress
=> All_Checks
);
2422 elsif Is_Array_Type
(Typ
) then
2424 Actual_Rhs
: Node_Id
:= Rhs
;
2427 while Nkind_In
(Actual_Rhs
, N_Type_Conversion
,
2428 N_Qualified_Expression
)
2430 Actual_Rhs
:= Expression
(Actual_Rhs
);
2433 Expand_Assign_Array
(N
, Actual_Rhs
);
2440 elsif Is_Record_Type
(Typ
) then
2441 Expand_Assign_Record
(N
);
2445 -- Scalar types. This is where we perform the processing related to the
2446 -- requirements of (RM 13.9.1(9-11)) concerning the handling of invalid
2449 elsif Is_Scalar_Type
(Typ
) then
2451 -- Case where right side is known valid
2453 if Expr_Known_Valid
(Rhs
) then
2455 -- Here the right side is valid, so it is fine. The case to deal
2456 -- with is when the left side is a local variable reference whose
2457 -- value is not currently known to be valid. If this is the case,
2458 -- and the assignment appears in an unconditional context, then
2459 -- we can mark the left side as now being valid if one of these
2460 -- conditions holds:
2462 -- The expression of the right side has Do_Range_Check set so
2463 -- that we know a range check will be performed. Note that it
2464 -- can be the case that a range check is omitted because we
2465 -- make the assumption that we can assume validity for operands
2466 -- appearing in the right side in determining whether a range
2467 -- check is required
2469 -- The subtype of the right side matches the subtype of the
2470 -- left side. In this case, even though we have not checked
2471 -- the range of the right side, we know it is in range of its
2472 -- subtype if the expression is valid.
2474 if Is_Local_Variable_Reference
(Lhs
)
2475 and then not Is_Known_Valid
(Entity
(Lhs
))
2476 and then In_Unconditional_Context
(N
)
2478 if Do_Range_Check
(Rhs
)
2479 or else Etype
(Lhs
) = Etype
(Rhs
)
2481 Set_Is_Known_Valid
(Entity
(Lhs
), True);
2485 -- Case where right side may be invalid in the sense of the RM
2486 -- reference above. The RM does not require that we check for the
2487 -- validity on an assignment, but it does require that the assignment
2488 -- of an invalid value not cause erroneous behavior.
2490 -- The general approach in GNAT is to use the Is_Known_Valid flag
2491 -- to avoid the need for validity checking on assignments. However
2492 -- in some cases, we have to do validity checking in order to make
2493 -- sure that the setting of this flag is correct.
2496 -- Validate right side if we are validating copies
2498 if Validity_Checks_On
2499 and then Validity_Check_Copies
2501 -- Skip this if left hand side is an array or record component
2502 -- and elementary component validity checks are suppressed.
2504 if Nkind_In
(Lhs
, N_Selected_Component
, N_Indexed_Component
)
2505 and then not Validity_Check_Components
2512 -- We can propagate this to the left side where appropriate
2514 if Is_Local_Variable_Reference
(Lhs
)
2515 and then not Is_Known_Valid
(Entity
(Lhs
))
2516 and then In_Unconditional_Context
(N
)
2518 Set_Is_Known_Valid
(Entity
(Lhs
), True);
2521 -- Otherwise check to see what should be done
2523 -- If left side is a local variable, then we just set its flag to
2524 -- indicate that its value may no longer be valid, since we are
2525 -- copying a potentially invalid value.
2527 elsif Is_Local_Variable_Reference
(Lhs
) then
2528 Set_Is_Known_Valid
(Entity
(Lhs
), False);
2530 -- Check for case of a nonlocal variable on the left side which
2531 -- is currently known to be valid. In this case, we simply ensure
2532 -- that the right side is valid. We only play the game of copying
2533 -- validity status for local variables, since we are doing this
2534 -- statically, not by tracing the full flow graph.
2536 elsif Is_Entity_Name
(Lhs
)
2537 and then Is_Known_Valid
(Entity
(Lhs
))
2539 -- Note: If Validity_Checking mode is set to none, we ignore
2540 -- the Ensure_Valid call so don't worry about that case here.
2544 -- In all other cases, we can safely copy an invalid value without
2545 -- worrying about the status of the left side. Since it is not a
2546 -- variable reference it will not be considered
2547 -- as being known to be valid in any case.
2558 when RE_Not_Available
=>
2561 end Expand_N_Assignment_Statement
;
2563 ------------------------------
2564 -- Expand_N_Block_Statement --
2565 ------------------------------
2567 -- Encode entity names defined in block statement
2569 procedure Expand_N_Block_Statement
(N
: Node_Id
) is
2571 Qualify_Entity_Names
(N
);
2572 end Expand_N_Block_Statement
;
2574 -----------------------------
2575 -- Expand_N_Case_Statement --
2576 -----------------------------
2578 procedure Expand_N_Case_Statement
(N
: Node_Id
) is
2579 Loc
: constant Source_Ptr
:= Sloc
(N
);
2580 Expr
: constant Node_Id
:= Expression
(N
);
2588 -- Check for the situation where we know at compile time which branch
2591 -- If the value is static but its subtype is predicated and the value
2592 -- does not obey the predicate, the value is marked non-static, and
2593 -- there can be no corresponding static alternative.
2595 if Compile_Time_Known_Value
(Expr
)
2596 and then (not Has_Predicates
(Etype
(Expr
))
2597 or else Is_Static_Expression
(Expr
))
2599 Alt
:= Find_Static_Alternative
(N
);
2601 -- Do not consider controlled objects found in a case statement which
2602 -- actually models a case expression because their early finalization
2603 -- will affect the result of the expression.
2605 if not From_Conditional_Expression
(N
) then
2606 Process_Statements_For_Controlled_Objects
(Alt
);
2609 -- Move statements from this alternative after the case statement.
2610 -- They are already analyzed, so will be skipped by the analyzer.
2612 Insert_List_After
(N
, Statements
(Alt
));
2614 -- That leaves the case statement as a shell. So now we can kill all
2615 -- other alternatives in the case statement.
2617 Kill_Dead_Code
(Expression
(N
));
2623 -- Loop through case alternatives, skipping pragmas, and skipping
2624 -- the one alternative that we select (and therefore retain).
2626 Dead_Alt
:= First
(Alternatives
(N
));
2627 while Present
(Dead_Alt
) loop
2629 and then Nkind
(Dead_Alt
) = N_Case_Statement_Alternative
2631 Kill_Dead_Code
(Statements
(Dead_Alt
), Warn_On_Deleted_Code
);
2638 Rewrite
(N
, Make_Null_Statement
(Loc
));
2642 -- Here if the choice is not determined at compile time
2645 Last_Alt
: constant Node_Id
:= Last
(Alternatives
(N
));
2647 Others_Present
: Boolean;
2648 Others_Node
: Node_Id
;
2650 Then_Stms
: List_Id
;
2651 Else_Stms
: List_Id
;
2654 if Nkind
(First
(Discrete_Choices
(Last_Alt
))) = N_Others_Choice
then
2655 Others_Present
:= True;
2656 Others_Node
:= Last_Alt
;
2658 Others_Present
:= False;
2661 -- First step is to worry about possible invalid argument. The RM
2662 -- requires (RM 5.4(13)) that if the result is invalid (e.g. it is
2663 -- outside the base range), then Constraint_Error must be raised.
2665 -- Case of validity check required (validity checks are on, the
2666 -- expression is not known to be valid, and the case statement
2667 -- comes from source -- no need to validity check internally
2668 -- generated case statements).
2670 if Validity_Check_Default
then
2671 Ensure_Valid
(Expr
);
2674 -- If there is only a single alternative, just replace it with the
2675 -- sequence of statements since obviously that is what is going to
2676 -- be executed in all cases.
2678 Len
:= List_Length
(Alternatives
(N
));
2682 -- We still need to evaluate the expression if it has any side
2685 Remove_Side_Effects
(Expression
(N
));
2686 Alt
:= First
(Alternatives
(N
));
2688 -- Do not consider controlled objects found in a case statement
2689 -- which actually models a case expression because their early
2690 -- finalization will affect the result of the expression.
2692 if not From_Conditional_Expression
(N
) then
2693 Process_Statements_For_Controlled_Objects
(Alt
);
2696 Insert_List_After
(N
, Statements
(Alt
));
2698 -- That leaves the case statement as a shell. The alternative that
2699 -- will be executed is reset to a null list. So now we can kill
2700 -- the entire case statement.
2702 Kill_Dead_Code
(Expression
(N
));
2703 Rewrite
(N
, Make_Null_Statement
(Loc
));
2706 -- An optimization. If there are only two alternatives, and only
2707 -- a single choice, then rewrite the whole case statement as an
2708 -- if statement, since this can result in subsequent optimizations.
2709 -- This helps not only with case statements in the source of a
2710 -- simple form, but also with generated code (discriminant check
2711 -- functions in particular).
2713 -- Note: it is OK to do this before expanding out choices for any
2714 -- static predicates, since the if statement processing will handle
2715 -- the static predicate case fine.
2718 Chlist
:= Discrete_Choices
(First
(Alternatives
(N
)));
2720 if List_Length
(Chlist
) = 1 then
2721 Choice
:= First
(Chlist
);
2723 Then_Stms
:= Statements
(First
(Alternatives
(N
)));
2724 Else_Stms
:= Statements
(Last
(Alternatives
(N
)));
2726 -- For TRUE, generate "expression", not expression = true
2728 if Nkind
(Choice
) = N_Identifier
2729 and then Entity
(Choice
) = Standard_True
2731 Cond
:= Expression
(N
);
2733 -- For FALSE, generate "expression" and switch then/else
2735 elsif Nkind
(Choice
) = N_Identifier
2736 and then Entity
(Choice
) = Standard_False
2738 Cond
:= Expression
(N
);
2739 Else_Stms
:= Statements
(First
(Alternatives
(N
)));
2740 Then_Stms
:= Statements
(Last
(Alternatives
(N
)));
2742 -- For a range, generate "expression in range"
2744 elsif Nkind
(Choice
) = N_Range
2745 or else (Nkind
(Choice
) = N_Attribute_Reference
2746 and then Attribute_Name
(Choice
) = Name_Range
)
2747 or else (Is_Entity_Name
(Choice
)
2748 and then Is_Type
(Entity
(Choice
)))
2752 Left_Opnd
=> Expression
(N
),
2753 Right_Opnd
=> Relocate_Node
(Choice
));
2755 -- A subtype indication is not a legal operator in a membership
2756 -- test, so retrieve its range.
2758 elsif Nkind
(Choice
) = N_Subtype_Indication
then
2761 Left_Opnd
=> Expression
(N
),
2764 (Range_Expression
(Constraint
(Choice
))));
2766 -- For any other subexpression "expression = value"
2771 Left_Opnd
=> Expression
(N
),
2772 Right_Opnd
=> Relocate_Node
(Choice
));
2775 -- Now rewrite the case as an IF
2778 Make_If_Statement
(Loc
,
2780 Then_Statements
=> Then_Stms
,
2781 Else_Statements
=> Else_Stms
));
2787 -- If the last alternative is not an Others choice, replace it with
2788 -- an N_Others_Choice. Note that we do not bother to call Analyze on
2789 -- the modified case statement, since it's only effect would be to
2790 -- compute the contents of the Others_Discrete_Choices which is not
2791 -- needed by the back end anyway.
2793 -- The reason for this is that the back end always needs some default
2794 -- for a switch, so if we have not supplied one in the processing
2795 -- above for validity checking, then we need to supply one here.
2797 if not Others_Present
then
2798 Others_Node
:= Make_Others_Choice
(Sloc
(Last_Alt
));
2799 Set_Others_Discrete_Choices
2800 (Others_Node
, Discrete_Choices
(Last_Alt
));
2801 Set_Discrete_Choices
(Last_Alt
, New_List
(Others_Node
));
2804 -- Deal with possible declarations of controlled objects, and also
2805 -- with rewriting choice sequences for static predicate references.
2807 Alt
:= First_Non_Pragma
(Alternatives
(N
));
2808 while Present
(Alt
) loop
2810 -- Do not consider controlled objects found in a case statement
2811 -- which actually models a case expression because their early
2812 -- finalization will affect the result of the expression.
2814 if not From_Conditional_Expression
(N
) then
2815 Process_Statements_For_Controlled_Objects
(Alt
);
2818 if Has_SP_Choice
(Alt
) then
2819 Expand_Static_Predicates_In_Choices
(Alt
);
2822 Next_Non_Pragma
(Alt
);
2825 end Expand_N_Case_Statement
;
2827 -----------------------------
2828 -- Expand_N_Exit_Statement --
2829 -----------------------------
2831 -- The only processing required is to deal with a possible C/Fortran
2832 -- boolean value used as the condition for the exit statement.
2834 procedure Expand_N_Exit_Statement
(N
: Node_Id
) is
2836 Adjust_Condition
(Condition
(N
));
2837 end Expand_N_Exit_Statement
;
2839 ----------------------------------
2840 -- Expand_Formal_Container_Loop --
2841 ----------------------------------
2843 procedure Expand_Formal_Container_Loop
(N
: Node_Id
) is
2844 Loc
: constant Source_Ptr
:= Sloc
(N
);
2845 Isc
: constant Node_Id
:= Iteration_Scheme
(N
);
2846 I_Spec
: constant Node_Id
:= Iterator_Specification
(Isc
);
2847 Cursor
: constant Entity_Id
:= Defining_Identifier
(I_Spec
);
2848 Container
: constant Node_Id
:= Entity
(Name
(I_Spec
));
2849 Stats
: constant List_Id
:= Statements
(N
);
2857 -- The expansion resembles the one for Ada containers, but the
2858 -- primitives mention the domain of iteration explicitly, and
2859 -- function First applied to the container yields a cursor directly.
2861 -- Cursor : Cursor_type := First (Container);
2862 -- while Has_Element (Cursor, Container) loop
2863 -- <original loop statements>
2864 -- Cursor := Next (Container, Cursor);
2867 Build_Formal_Container_Iteration
2868 (N
, Container
, Cursor
, Init
, Advance
, New_Loop
);
2870 Set_Ekind
(Cursor
, E_Variable
);
2871 Append_To
(Stats
, Advance
);
2873 -- Build block to capture declaration of cursor entity.
2876 Make_Block_Statement
(Loc
,
2877 Declarations
=> New_List
(Init
),
2878 Handled_Statement_Sequence
=>
2879 Make_Handled_Sequence_Of_Statements
(Loc
,
2880 Statements
=> New_List
(New_Loop
)));
2882 Rewrite
(N
, Blk_Nod
);
2884 end Expand_Formal_Container_Loop
;
2886 ------------------------------------------
2887 -- Expand_Formal_Container_Element_Loop --
2888 ------------------------------------------
2890 procedure Expand_Formal_Container_Element_Loop
(N
: Node_Id
) is
2891 Loc
: constant Source_Ptr
:= Sloc
(N
);
2892 Isc
: constant Node_Id
:= Iteration_Scheme
(N
);
2893 I_Spec
: constant Node_Id
:= Iterator_Specification
(Isc
);
2894 Element
: constant Entity_Id
:= Defining_Identifier
(I_Spec
);
2895 Container
: constant Node_Id
:= Entity
(Name
(I_Spec
));
2896 Container_Typ
: constant Entity_Id
:= Base_Type
(Etype
(Container
));
2897 Stats
: constant List_Id
:= Statements
(N
);
2899 Cursor
: constant Entity_Id
:=
2900 Make_Defining_Identifier
(Loc
,
2901 Chars
=> New_External_Name
(Chars
(Element
), 'C'));
2902 Elmt_Decl
: Node_Id
;
2905 Element_Op
: constant Entity_Id
:=
2906 Get_Iterable_Type_Primitive
(Container_Typ
, Name_Element
);
2913 -- For an element iterator, the Element aspect must be present,
2914 -- (this is checked during analysis) and the expansion takes the form:
2916 -- Cursor : Cursor_type := First (Container);
2917 -- Elmt : Element_Type;
2918 -- while Has_Element (Cursor, Container) loop
2919 -- Elmt := Element (Container, Cursor);
2920 -- <original loop statements>
2921 -- Cursor := Next (Container, Cursor);
2924 Build_Formal_Container_Iteration
2925 (N
, Container
, Cursor
, Init
, Advance
, New_Loop
);
2927 Set_Ekind
(Cursor
, E_Variable
);
2928 Insert_Action
(N
, Init
);
2930 -- Declaration for Element.
2933 Make_Object_Declaration
(Loc
,
2934 Defining_Identifier
=> Element
,
2935 Object_Definition
=> New_Occurrence_Of
(Etype
(Element_Op
), Loc
));
2937 -- The element is only modified in expanded code, so it appears as
2938 -- unassigned to the warning machinery. We must suppress this spurious
2939 -- warning explicitly.
2941 Set_Warnings_Off
(Element
);
2944 Make_Assignment_Statement
(Loc
,
2945 Name
=> New_Occurrence_Of
(Element
, Loc
),
2947 Make_Function_Call
(Loc
,
2948 Name
=> New_Occurrence_Of
(Element_Op
, Loc
),
2949 Parameter_Associations
=> New_List
(
2950 New_Occurrence_Of
(Container
, Loc
),
2951 New_Occurrence_Of
(Cursor
, Loc
))));
2953 Prepend
(Elmt_Ref
, Stats
);
2954 Append_To
(Stats
, Advance
);
2956 -- The loop is rewritten as a block, to hold the element declaration
2959 Make_Block_Statement
(Loc
,
2960 Declarations
=> New_List
(Elmt_Decl
),
2961 Handled_Statement_Sequence
=>
2962 Make_Handled_Sequence_Of_Statements
(Loc
,
2963 Statements
=> New_List
(New_Loop
)));
2965 Rewrite
(N
, New_Loop
);
2967 -- The loop parameter is declared by an object declaration, but within
2968 -- the loop we must prevent user assignments to it, so we analyze the
2969 -- declaration and reset the entity kind, before analyzing the rest of
2972 Analyze
(Elmt_Decl
);
2973 Set_Ekind
(Defining_Identifier
(Elmt_Decl
), E_Loop_Parameter
);
2974 Set_Assignment_OK
(Name
(Elmt_Ref
));
2977 end Expand_Formal_Container_Element_Loop
;
2979 -----------------------------
2980 -- Expand_N_Goto_Statement --
2981 -----------------------------
2983 -- Add poll before goto if polling active
2985 procedure Expand_N_Goto_Statement
(N
: Node_Id
) is
2987 Generate_Poll_Call
(N
);
2988 end Expand_N_Goto_Statement
;
2990 ---------------------------
2991 -- Expand_N_If_Statement --
2992 ---------------------------
2994 -- First we deal with the case of C and Fortran convention boolean values,
2995 -- with zero/non-zero semantics.
2997 -- Second, we deal with the obvious rewriting for the cases where the
2998 -- condition of the IF is known at compile time to be True or False.
3000 -- Third, we remove elsif parts which have non-empty Condition_Actions and
3001 -- rewrite as independent if statements. For example:
3012 -- <<condition actions of y>>
3018 -- This rewriting is needed if at least one elsif part has a non-empty
3019 -- Condition_Actions list. We also do the same processing if there is a
3020 -- constant condition in an elsif part (in conjunction with the first
3021 -- processing step mentioned above, for the recursive call made to deal
3022 -- with the created inner if, this deals with properly optimizing the
3023 -- cases of constant elsif conditions).
3025 procedure Expand_N_If_Statement
(N
: Node_Id
) is
3026 Loc
: constant Source_Ptr
:= Sloc
(N
);
3031 Warn_If_Deleted
: constant Boolean :=
3032 Warn_On_Deleted_Code
and then Comes_From_Source
(N
);
3033 -- Indicates whether we want warnings when we delete branches of the
3034 -- if statement based on constant condition analysis. We never want
3035 -- these warnings for expander generated code.
3038 -- Do not consider controlled objects found in an if statement which
3039 -- actually models an if expression because their early finalization
3040 -- will affect the result of the expression.
3042 if not From_Conditional_Expression
(N
) then
3043 Process_Statements_For_Controlled_Objects
(N
);
3046 Adjust_Condition
(Condition
(N
));
3048 -- The following loop deals with constant conditions for the IF. We
3049 -- need a loop because as we eliminate False conditions, we grab the
3050 -- first elsif condition and use it as the primary condition.
3052 while Compile_Time_Known_Value
(Condition
(N
)) loop
3054 -- If condition is True, we can simply rewrite the if statement now
3055 -- by replacing it by the series of then statements.
3057 if Is_True
(Expr_Value
(Condition
(N
))) then
3059 -- All the else parts can be killed
3061 Kill_Dead_Code
(Elsif_Parts
(N
), Warn_If_Deleted
);
3062 Kill_Dead_Code
(Else_Statements
(N
), Warn_If_Deleted
);
3064 Hed
:= Remove_Head
(Then_Statements
(N
));
3065 Insert_List_After
(N
, Then_Statements
(N
));
3069 -- If condition is False, then we can delete the condition and
3070 -- the Then statements
3073 -- We do not delete the condition if constant condition warnings
3074 -- are enabled, since otherwise we end up deleting the desired
3075 -- warning. Of course the backend will get rid of this True/False
3076 -- test anyway, so nothing is lost here.
3078 if not Constant_Condition_Warnings
then
3079 Kill_Dead_Code
(Condition
(N
));
3082 Kill_Dead_Code
(Then_Statements
(N
), Warn_If_Deleted
);
3084 -- If there are no elsif statements, then we simply replace the
3085 -- entire if statement by the sequence of else statements.
3087 if No
(Elsif_Parts
(N
)) then
3088 if No
(Else_Statements
(N
))
3089 or else Is_Empty_List
(Else_Statements
(N
))
3092 Make_Null_Statement
(Sloc
(N
)));
3094 Hed
:= Remove_Head
(Else_Statements
(N
));
3095 Insert_List_After
(N
, Else_Statements
(N
));
3101 -- If there are elsif statements, the first of them becomes the
3102 -- if/then section of the rebuilt if statement This is the case
3103 -- where we loop to reprocess this copied condition.
3106 Hed
:= Remove_Head
(Elsif_Parts
(N
));
3107 Insert_Actions
(N
, Condition_Actions
(Hed
));
3108 Set_Condition
(N
, Condition
(Hed
));
3109 Set_Then_Statements
(N
, Then_Statements
(Hed
));
3111 -- Hed might have been captured as the condition determining
3112 -- the current value for an entity. Now it is detached from
3113 -- the tree, so a Current_Value pointer in the condition might
3114 -- need to be updated.
3116 Set_Current_Value_Condition
(N
);
3118 if Is_Empty_List
(Elsif_Parts
(N
)) then
3119 Set_Elsif_Parts
(N
, No_List
);
3125 -- Loop through elsif parts, dealing with constant conditions and
3126 -- possible condition actions that are present.
3128 if Present
(Elsif_Parts
(N
)) then
3129 E
:= First
(Elsif_Parts
(N
));
3130 while Present
(E
) loop
3132 -- Do not consider controlled objects found in an if statement
3133 -- which actually models an if expression because their early
3134 -- finalization will affect the result of the expression.
3136 if not From_Conditional_Expression
(N
) then
3137 Process_Statements_For_Controlled_Objects
(E
);
3140 Adjust_Condition
(Condition
(E
));
3142 -- If there are condition actions, then rewrite the if statement
3143 -- as indicated above. We also do the same rewrite for a True or
3144 -- False condition. The further processing of this constant
3145 -- condition is then done by the recursive call to expand the
3146 -- newly created if statement
3148 if Present
(Condition_Actions
(E
))
3149 or else Compile_Time_Known_Value
(Condition
(E
))
3151 -- Note this is not an implicit if statement, since it is part
3152 -- of an explicit if statement in the source (or of an implicit
3153 -- if statement that has already been tested).
3156 Make_If_Statement
(Sloc
(E
),
3157 Condition
=> Condition
(E
),
3158 Then_Statements
=> Then_Statements
(E
),
3159 Elsif_Parts
=> No_List
,
3160 Else_Statements
=> Else_Statements
(N
));
3162 -- Elsif parts for new if come from remaining elsif's of parent
3164 while Present
(Next
(E
)) loop
3165 if No
(Elsif_Parts
(New_If
)) then
3166 Set_Elsif_Parts
(New_If
, New_List
);
3169 Append
(Remove_Next
(E
), Elsif_Parts
(New_If
));
3172 Set_Else_Statements
(N
, New_List
(New_If
));
3174 if Present
(Condition_Actions
(E
)) then
3175 Insert_List_Before
(New_If
, Condition_Actions
(E
));
3180 if Is_Empty_List
(Elsif_Parts
(N
)) then
3181 Set_Elsif_Parts
(N
, No_List
);
3187 -- No special processing for that elsif part, move to next
3195 -- Some more optimizations applicable if we still have an IF statement
3197 if Nkind
(N
) /= N_If_Statement
then
3201 -- Another optimization, special cases that can be simplified
3203 -- if expression then
3209 -- can be changed to:
3211 -- return expression;
3215 -- if expression then
3221 -- can be changed to:
3223 -- return not (expression);
3225 -- Only do these optimizations if we are at least at -O1 level and
3226 -- do not do them if control flow optimizations are suppressed.
3228 if Optimization_Level
> 0
3229 and then not Opt
.Suppress_Control_Flow_Optimizations
3231 if Nkind
(N
) = N_If_Statement
3232 and then No
(Elsif_Parts
(N
))
3233 and then Present
(Else_Statements
(N
))
3234 and then List_Length
(Then_Statements
(N
)) = 1
3235 and then List_Length
(Else_Statements
(N
)) = 1
3238 Then_Stm
: constant Node_Id
:= First
(Then_Statements
(N
));
3239 Else_Stm
: constant Node_Id
:= First
(Else_Statements
(N
));
3242 if Nkind
(Then_Stm
) = N_Simple_Return_Statement
3244 Nkind
(Else_Stm
) = N_Simple_Return_Statement
3247 Then_Expr
: constant Node_Id
:= Expression
(Then_Stm
);
3248 Else_Expr
: constant Node_Id
:= Expression
(Else_Stm
);
3251 if Nkind
(Then_Expr
) = N_Identifier
3253 Nkind
(Else_Expr
) = N_Identifier
3255 if Entity
(Then_Expr
) = Standard_True
3256 and then Entity
(Else_Expr
) = Standard_False
3259 Make_Simple_Return_Statement
(Loc
,
3260 Expression
=> Relocate_Node
(Condition
(N
))));
3264 elsif Entity
(Then_Expr
) = Standard_False
3265 and then Entity
(Else_Expr
) = Standard_True
3268 Make_Simple_Return_Statement
(Loc
,
3272 Relocate_Node
(Condition
(N
)))));
3282 end Expand_N_If_Statement
;
3284 --------------------------
3285 -- Expand_Iterator_Loop --
3286 --------------------------
3288 procedure Expand_Iterator_Loop
(N
: Node_Id
) is
3289 Isc
: constant Node_Id
:= Iteration_Scheme
(N
);
3290 I_Spec
: constant Node_Id
:= Iterator_Specification
(Isc
);
3292 Container
: constant Node_Id
:= Name
(I_Spec
);
3293 Container_Typ
: constant Entity_Id
:= Base_Type
(Etype
(Container
));
3296 -- Processing for arrays
3298 if Is_Array_Type
(Container_Typ
) then
3299 pragma Assert
(Of_Present
(I_Spec
));
3300 Expand_Iterator_Loop_Over_Array
(N
);
3302 elsif Has_Aspect
(Container_Typ
, Aspect_Iterable
) then
3303 if Of_Present
(I_Spec
) then
3304 Expand_Formal_Container_Element_Loop
(N
);
3306 Expand_Formal_Container_Loop
(N
);
3309 -- Processing for containers
3312 Expand_Iterator_Loop_Over_Container
3313 (N
, Isc
, I_Spec
, Container
, Container_Typ
);
3315 end Expand_Iterator_Loop
;
3317 -------------------------------------
3318 -- Expand_Iterator_Loop_Over_Array --
3319 -------------------------------------
3321 procedure Expand_Iterator_Loop_Over_Array
(N
: Node_Id
) is
3322 Isc
: constant Node_Id
:= Iteration_Scheme
(N
);
3323 I_Spec
: constant Node_Id
:= Iterator_Specification
(Isc
);
3324 Array_Node
: constant Node_Id
:= Name
(I_Spec
);
3325 Array_Typ
: constant Entity_Id
:= Base_Type
(Etype
(Array_Node
));
3326 Array_Dim
: constant Pos
:= Number_Dimensions
(Array_Typ
);
3327 Id
: constant Entity_Id
:= Defining_Identifier
(I_Spec
);
3328 Loc
: constant Source_Ptr
:= Sloc
(N
);
3329 Stats
: constant List_Id
:= Statements
(N
);
3330 Core_Loop
: Node_Id
;
3333 Iterator
: Entity_Id
;
3335 -- Start of processing for Expand_Iterator_Loop_Over_Array
3338 -- for Element of Array loop
3340 -- This case requires an internally generated cursor to iterate over
3343 if Of_Present
(I_Spec
) then
3344 Iterator
:= Make_Temporary
(Loc
, 'C');
3347 -- Element : Component_Type renames Array (Iterator);
3348 -- Iterator is the index value, or a list of index values
3349 -- in the case of a multidimensional array.
3352 Make_Indexed_Component
(Loc
,
3353 Prefix
=> Relocate_Node
(Array_Node
),
3354 Expressions
=> New_List
(New_Occurrence_Of
(Iterator
, Loc
)));
3357 Make_Object_Renaming_Declaration
(Loc
,
3358 Defining_Identifier
=> Id
,
3360 New_Occurrence_Of
(Component_Type
(Array_Typ
), Loc
),
3363 -- Mark the loop variable as needing debug info, so that expansion
3364 -- of the renaming will result in Materialize_Entity getting set via
3365 -- Debug_Renaming_Declaration. (This setting is needed here because
3366 -- the setting in Freeze_Entity comes after the expansion, which is
3369 Set_Debug_Info_Needed
(Id
);
3371 -- for Index in Array loop
3373 -- This case utilizes the already given iterator name
3381 -- for Iterator in [reverse] Array'Range (Array_Dim) loop
3382 -- Element : Component_Type renames Array (Iterator);
3383 -- <original loop statements>
3386 -- If this is an iteration over a multidimensional array, the
3387 -- innermost loop is over the last dimension in Ada, and over
3388 -- the first dimension in Fortran.
3390 if Convention
(Array_Typ
) = Convention_Fortran
then
3397 Make_Loop_Statement
(Loc
,
3399 Make_Iteration_Scheme
(Loc
,
3400 Loop_Parameter_Specification
=>
3401 Make_Loop_Parameter_Specification
(Loc
,
3402 Defining_Identifier
=> Iterator
,
3403 Discrete_Subtype_Definition
=>
3404 Make_Attribute_Reference
(Loc
,
3405 Prefix
=> Relocate_Node
(Array_Node
),
3406 Attribute_Name
=> Name_Range
,
3407 Expressions
=> New_List
(
3408 Make_Integer_Literal
(Loc
, Dim1
))),
3409 Reverse_Present
=> Reverse_Present
(I_Spec
))),
3410 Statements
=> Stats
,
3411 End_Label
=> Empty
);
3413 -- Processing for multidimensional array. The body of each loop is
3414 -- a loop over a previous dimension, going in decreasing order in Ada
3415 -- and in increasing order in Fortran.
3417 if Array_Dim
> 1 then
3418 for Dim
in 1 .. Array_Dim
- 1 loop
3419 if Convention
(Array_Typ
) = Convention_Fortran
then
3422 Dim1
:= Array_Dim
- Dim
;
3425 Iterator
:= Make_Temporary
(Loc
, 'C');
3427 -- Generate the dimension loops starting from the innermost one
3429 -- for Iterator in [reverse] Array'Range (Array_Dim - Dim) loop
3434 Make_Loop_Statement
(Loc
,
3436 Make_Iteration_Scheme
(Loc
,
3437 Loop_Parameter_Specification
=>
3438 Make_Loop_Parameter_Specification
(Loc
,
3439 Defining_Identifier
=> Iterator
,
3440 Discrete_Subtype_Definition
=>
3441 Make_Attribute_Reference
(Loc
,
3442 Prefix
=> Relocate_Node
(Array_Node
),
3443 Attribute_Name
=> Name_Range
,
3444 Expressions
=> New_List
(
3445 Make_Integer_Literal
(Loc
, Dim1
))),
3446 Reverse_Present
=> Reverse_Present
(I_Spec
))),
3447 Statements
=> New_List
(Core_Loop
),
3448 End_Label
=> Empty
);
3450 -- Update the previously created object renaming declaration with
3451 -- the new iterator, by adding the index of the next loop to the
3452 -- indexed component, in the order that corresponds to the
3455 if Convention
(Array_Typ
) = Convention_Fortran
then
3456 Append_To
(Expressions
(Ind_Comp
),
3457 New_Occurrence_Of
(Iterator
, Loc
));
3459 Prepend_To
(Expressions
(Ind_Comp
),
3460 New_Occurrence_Of
(Iterator
, Loc
));
3465 -- Inherit the loop identifier from the original loop. This ensures that
3466 -- the scope stack is consistent after the rewriting.
3468 if Present
(Identifier
(N
)) then
3469 Set_Identifier
(Core_Loop
, Relocate_Node
(Identifier
(N
)));
3472 Rewrite
(N
, Core_Loop
);
3474 end Expand_Iterator_Loop_Over_Array
;
3476 -----------------------------------------
3477 -- Expand_Iterator_Loop_Over_Container --
3478 -----------------------------------------
3480 -- For a 'for ... in' loop, such as:
3482 -- for Cursor in Iterator_Function (...) loop
3488 -- Iter : Iterator_Type := Iterator_Function (...);
3489 -- Cursor : Cursor_type := First (Iter); -- or Last for "reverse"
3490 -- while Has_Element (Cursor) loop
3493 -- Cursor := Iter.Next (Cursor); -- or Prev for "reverse"
3496 -- For a 'for ... of' loop, such as:
3498 -- for X of Container loop
3502 -- the RM implies the generation of:
3504 -- Iter : Iterator_Type := Container.Iterate; -- the Default_Iterator
3505 -- Cursor : Cursor_Type := First (Iter); -- or Last for "reverse"
3506 -- while Has_Element (Cursor) loop
3508 -- X : Element_Type renames Element (Cursor).Element.all;
3509 -- -- or Constant_Element
3513 -- Cursor := Iter.Next (Cursor); -- or Prev for "reverse"
3516 -- In the general case, we do what the RM says. However, the operations
3517 -- Element and Iter.Next are slow, which is bad inside a loop, because they
3518 -- involve dispatching via interfaces, secondary stack manipulation,
3519 -- Busy/Lock incr/decr, and adjust/finalization/at-end handling. So for the
3520 -- predefined containers, we use an equivalent but optimized expansion.
3522 -- In the optimized case, we make use of these:
3524 -- procedure Next (Position : in out Cursor); -- instead of Iter.Next
3526 -- function Pseudo_Reference
3527 -- (Container : aliased Vector'Class) return Reference_Control_Type;
3529 -- type Element_Access is access all Element_Type;
3531 -- function Get_Element_Access
3532 -- (Position : Cursor) return not null Element_Access;
3534 -- Next is declared in the visible part of the container packages.
3535 -- The other three are added in the private part. (We're not supposed to
3536 -- pollute the namespace for clients. The compiler has no trouble breaking
3537 -- privacy to call things in the private part of an instance.)
3541 -- for X of My_Vector loop
3542 -- X.Count := X.Count + 1;
3546 -- The compiler will generate:
3548 -- Iter : Reversible_Iterator'Class := Iterate (My_Vector);
3549 -- -- Reversible_Iterator is an interface. Iterate is the
3550 -- -- Default_Iterator aspect of Vector. This increments Lock,
3551 -- -- disallowing tampering with cursors. Unfortunately, it does not
3552 -- -- increment Busy. The result of Iterate is Limited_Controlled;
3553 -- -- finalization will decrement Lock. This is a build-in-place
3554 -- -- dispatching call to Iterate.
3556 -- Cur : Cursor := First (Iter); -- or Last
3557 -- -- Dispatching call via interface.
3559 -- Control : Reference_Control_Type := Pseudo_Reference (My_Vector);
3560 -- -- Pseudo_Reference increments Busy, to detect tampering with
3561 -- -- elements, as required by RM. Also redundantly increment
3562 -- -- Lock. Finalization of Control will decrement both Busy and
3563 -- -- Lock. Pseudo_Reference returns a record containing a pointer to
3564 -- -- My_Vector, used by Finalize.
3566 -- -- Control is not used below, except to finalize it -- it's purely
3567 -- -- an RAII thing. This is needed because we are eliminating the
3568 -- -- call to Reference within the loop.
3570 -- while Has_Element (Cur) loop
3572 -- X : My_Element renames Get_Element_Access (Cur).all;
3573 -- -- Get_Element_Access returns a pointer to the element
3574 -- -- designated by Cur. No dispatching here, and no horsing
3575 -- -- around with access discriminants. This is instead of the
3578 -- -- X : My_Element renames Reference (Cur).Element.all;
3580 -- -- which creates a controlled object.
3582 -- -- Any attempt to tamper with My_Vector here in the loop
3583 -- -- will correctly raise Program_Error, because of the
3586 -- X.Count := X.Count + 1;
3589 -- Next (Cur); -- or Prev
3590 -- -- This is instead of "Cur := Next (Iter, Cur);"
3592 -- -- No finalization here
3594 -- Finalize Iter and Control here, decrementing Lock twice and Busy
3597 -- This optimization makes "for ... of" loops over 30 times faster in cases
3600 procedure Expand_Iterator_Loop_Over_Container
3604 Container
: Node_Id
;
3605 Container_Typ
: Entity_Id
)
3607 Id
: constant Entity_Id
:= Defining_Identifier
(I_Spec
);
3608 Loc
: constant Source_Ptr
:= Sloc
(N
);
3610 I_Kind
: constant Entity_Kind
:= Ekind
(Id
);
3612 Iterator
: Entity_Id
;
3614 Stats
: constant List_Id
:= Statements
(N
);
3616 Element_Type
: constant Entity_Id
:= Etype
(Id
);
3617 Iter_Type
: Entity_Id
;
3620 Name_Init
: Name_Id
;
3621 Name_Step
: Name_Id
;
3623 Fast_Element_Access_Op
, Fast_Step_Op
: Entity_Id
:= Empty
;
3624 -- Only for optimized version of "for ... of"
3627 -- Determine the advancement and initialization steps for the cursor.
3628 -- Analysis of the expanded loop will verify that the container has a
3629 -- reverse iterator.
3631 if Reverse_Present
(I_Spec
) then
3632 Name_Init
:= Name_Last
;
3633 Name_Step
:= Name_Previous
;
3635 Name_Init
:= Name_First
;
3636 Name_Step
:= Name_Next
;
3639 -- The type of the iterator is the return type of the Iterate function
3640 -- used. For the "of" form this is the default iterator for the type,
3641 -- otherwise it is the type of the explicit function used in the
3642 -- iterator specification. The most common case will be an Iterate
3643 -- function in the container package.
3645 -- The Iterator type is declared in an instance within the container
3646 -- package itself, for example:
3648 -- package Vector_Iterator_Interfaces is new
3649 -- Ada.Iterator_Interfaces (Cursor, Has_Element);
3651 -- If the container type is a derived type, the cursor type is found in
3652 -- the package of the ultimate ancestor type.
3654 if Is_Derived_Type
(Container_Typ
) then
3655 Pack
:= Scope
(Root_Type
(Container_Typ
));
3657 Pack
:= Scope
(Container_Typ
);
3660 Iter_Type
:= Etype
(Name
(I_Spec
));
3662 if Of_Present
(I_Spec
) then
3664 Container_Arg
: Node_Id
;
3666 function Get_Default_Iterator
3667 (T
: Entity_Id
) return Entity_Id
;
3668 -- If the container is a derived type, the aspect holds the parent
3669 -- operation. The required one is a primitive of the derived type
3670 -- and is either inherited or overridden. Also sets Container_Arg.
3672 --------------------------
3673 -- Get_Default_Iterator --
3674 --------------------------
3676 function Get_Default_Iterator
3677 (T
: Entity_Id
) return Entity_Id
3679 Iter
: constant Entity_Id
:=
3680 Entity
(Find_Value_Of_Aspect
(T
, Aspect_Default_Iterator
));
3685 Container_Arg
:= New_Copy_Tree
(Container
);
3687 -- A previous version of GNAT allowed indexing aspects to
3688 -- be redefined on derived container types, while the
3689 -- default iterator was inherited from the parent type.
3690 -- This non-standard extension is preserved temporarily for
3691 -- use by the modelling project under debug flag d.X.
3693 if Debug_Flag_Dot_XX
then
3694 if Base_Type
(Etype
(Container
)) /=
3695 Base_Type
(Etype
(First_Formal
(Iter
)))
3698 Make_Type_Conversion
(Loc
,
3701 (Etype
(First_Formal
(Iter
)), Loc
),
3702 Expression
=> Container_Arg
);
3707 elsif Is_Derived_Type
(T
) then
3709 -- The default iterator must be a primitive operation of the
3710 -- type, at the same dispatch slot position.
3712 Prim
:= First_Elmt
(Primitive_Operations
(T
));
3713 while Present
(Prim
) loop
3716 if Chars
(Op
) = Chars
(Iter
)
3717 and then DT_Position
(Op
) = DT_Position
(Iter
)
3725 -- Default iterator must exist
3727 pragma Assert
(False);
3729 -- Otherwise not a derived type
3734 end Get_Default_Iterator
;
3736 Default_Iter
: Entity_Id
;
3739 Reference_Control_Type
: Entity_Id
:= Empty
;
3740 Pseudo_Reference
: Entity_Id
:= Empty
;
3742 -- Start of processing for Handle_Of
3745 if Is_Class_Wide_Type
(Container_Typ
) then
3747 Get_Default_Iterator
(Etype
(Base_Type
(Container_Typ
)));
3749 Default_Iter
:= Get_Default_Iterator
(Etype
(Container
));
3752 Cursor
:= Make_Temporary
(Loc
, 'C');
3754 -- For a container element iterator, the iterator type is obtained
3755 -- from the corresponding aspect, whose return type is descended
3756 -- from the corresponding interface type in some instance of
3757 -- Ada.Iterator_Interfaces. The actuals of that instantiation
3758 -- are Cursor and Has_Element.
3760 Iter_Type
:= Etype
(Default_Iter
);
3762 -- Find declarations needed for "for ... of" optimization
3764 Ent
:= First_Entity
(Pack
);
3765 while Present
(Ent
) loop
3766 if Chars
(Ent
) = Name_Get_Element_Access
then
3767 Fast_Element_Access_Op
:= Ent
;
3769 elsif Chars
(Ent
) = Name_Step
3770 and then Ekind
(Ent
) = E_Procedure
3772 Fast_Step_Op
:= Ent
;
3774 elsif Chars
(Ent
) = Name_Reference_Control_Type
then
3775 Reference_Control_Type
:= Ent
;
3777 elsif Chars
(Ent
) = Name_Pseudo_Reference
then
3778 Pseudo_Reference
:= Ent
;
3784 if Present
(Reference_Control_Type
)
3785 and then Present
(Pseudo_Reference
)
3788 Make_Object_Declaration
(Loc
,
3789 Defining_Identifier
=> Make_Temporary
(Loc
, 'D'),
3790 Object_Definition
=>
3791 New_Occurrence_Of
(Reference_Control_Type
, Loc
),
3793 Make_Function_Call
(Loc
,
3795 New_Occurrence_Of
(Pseudo_Reference
, Loc
),
3796 Parameter_Associations
=>
3797 New_List
(New_Copy_Tree
(Container_Arg
)))));
3800 -- The iterator type, which is a class-wide type, may itself be
3801 -- derived locally, so the desired instantiation is the scope of
3802 -- the root type of the iterator type. Currently, Pack is the
3803 -- container instance; this overwrites it with the iterator
3806 Pack
:= Scope
(Root_Type
(Etype
(Iter_Type
)));
3808 -- Rewrite domain of iteration as a call to the default iterator
3809 -- for the container type.
3811 Rewrite
(Name
(I_Spec
),
3812 Make_Function_Call
(Loc
,
3814 New_Occurrence_Of
(Default_Iter
, Loc
),
3815 Parameter_Associations
=> New_List
(Container_Arg
)));
3816 Analyze_And_Resolve
(Name
(I_Spec
));
3818 -- Find cursor type in proper iterator package, which is an
3819 -- instantiation of Iterator_Interfaces.
3821 Ent
:= First_Entity
(Pack
);
3822 while Present
(Ent
) loop
3823 if Chars
(Ent
) = Name_Cursor
then
3824 Set_Etype
(Cursor
, Etype
(Ent
));
3831 if Present
(Fast_Element_Access_Op
) then
3833 Make_Object_Renaming_Declaration
(Loc
,
3834 Defining_Identifier
=> Id
,
3836 New_Occurrence_Of
(Element_Type
, Loc
),
3838 Make_Explicit_Dereference
(Loc
,
3840 Make_Function_Call
(Loc
,
3842 New_Occurrence_Of
(Fast_Element_Access_Op
, Loc
),
3843 Parameter_Associations
=>
3844 New_List
(New_Occurrence_Of
(Cursor
, Loc
)))));
3848 Make_Object_Renaming_Declaration
(Loc
,
3849 Defining_Identifier
=> Id
,
3851 New_Occurrence_Of
(Element_Type
, Loc
),
3853 Make_Indexed_Component
(Loc
,
3854 Prefix
=> Relocate_Node
(Container_Arg
),
3856 New_List
(New_Occurrence_Of
(Cursor
, Loc
))));
3859 -- The defining identifier in the iterator is user-visible
3860 -- and must be visible in the debugger.
3862 Set_Debug_Info_Needed
(Id
);
3864 -- If the container does not have a variable indexing aspect,
3865 -- the element is a constant in the loop.
3867 if No
(Find_Value_Of_Aspect
3868 (Container_Typ
, Aspect_Variable_Indexing
))
3870 Set_Ekind
(Id
, E_Constant
);
3873 Prepend_To
(Stats
, Decl
);
3876 -- X in Iterate (S) : type of iterator is type of explicitly
3877 -- given Iterate function, and the loop variable is the cursor.
3878 -- It will be assigned in the loop and must be a variable.
3884 Iterator
:= Make_Temporary
(Loc
, 'I');
3886 -- For both iterator forms, add a call to the step operation to
3887 -- advance the cursor. Generate:
3889 -- Cursor := Iterator.Next (Cursor);
3893 -- Cursor := Next (Cursor);
3895 if Present
(Fast_Element_Access_Op
) and then Present
(Fast_Step_Op
) then
3897 Step_Call
: Node_Id
;
3898 Curs_Name
: constant Node_Id
:= New_Occurrence_Of
(Cursor
, Loc
);
3901 Make_Procedure_Call_Statement
(Loc
,
3903 New_Occurrence_Of
(Fast_Step_Op
, Loc
),
3904 Parameter_Associations
=> New_List
(Curs_Name
));
3906 Append_To
(Stats
, Step_Call
);
3907 Set_Assignment_OK
(Curs_Name
);
3916 Make_Function_Call
(Loc
,
3918 Make_Selected_Component
(Loc
,
3919 Prefix
=> New_Occurrence_Of
(Iterator
, Loc
),
3920 Selector_Name
=> Make_Identifier
(Loc
, Name_Step
)),
3921 Parameter_Associations
=> New_List
(
3922 New_Occurrence_Of
(Cursor
, Loc
)));
3925 Make_Assignment_Statement
(Loc
,
3926 Name
=> New_Occurrence_Of
(Cursor
, Loc
),
3927 Expression
=> Rhs
));
3928 Set_Assignment_OK
(Name
(Last
(Stats
)));
3933 -- while Has_Element (Cursor) loop
3937 -- Has_Element is the second actual in the iterator package
3940 Make_Loop_Statement
(Loc
,
3942 Make_Iteration_Scheme
(Loc
,
3944 Make_Function_Call
(Loc
,
3947 Next_Entity
(First_Entity
(Pack
)), Loc
),
3948 Parameter_Associations
=>
3949 New_List
(New_Occurrence_Of
(Cursor
, Loc
)))),
3951 Statements
=> Stats
,
3952 End_Label
=> Empty
);
3954 -- If present, preserve identifier of loop, which can be used in
3955 -- an exit statement in the body.
3957 if Present
(Identifier
(N
)) then
3958 Set_Identifier
(New_Loop
, Relocate_Node
(Identifier
(N
)));
3961 -- Create the declarations for Iterator and cursor and insert them
3962 -- before the source loop. Given that the domain of iteration is already
3963 -- an entity, the iterator is just a renaming of that entity. Possible
3967 Make_Object_Renaming_Declaration
(Loc
,
3968 Defining_Identifier
=> Iterator
,
3969 Subtype_Mark
=> New_Occurrence_Of
(Iter_Type
, Loc
),
3970 Name
=> Relocate_Node
(Name
(I_Spec
))));
3972 -- Create declaration for cursor
3975 Cursor_Decl
: constant Node_Id
:=
3976 Make_Object_Declaration
(Loc
,
3977 Defining_Identifier
=> Cursor
,
3978 Object_Definition
=>
3979 New_Occurrence_Of
(Etype
(Cursor
), Loc
),
3981 Make_Selected_Component
(Loc
,
3982 Prefix
=> New_Occurrence_Of
(Iterator
, Loc
),
3984 Make_Identifier
(Loc
, Name_Init
)));
3987 -- The cursor is only modified in expanded code, so it appears
3988 -- as unassigned to the warning machinery. We must suppress this
3989 -- spurious warning explicitly. The cursor's kind is that of the
3990 -- original loop parameter (it is a constant if the domain of
3991 -- iteration is constant).
3993 Set_Warnings_Off
(Cursor
);
3994 Set_Assignment_OK
(Cursor_Decl
);
3996 Insert_Action
(N
, Cursor_Decl
);
3997 Set_Ekind
(Cursor
, I_Kind
);
4000 -- If the range of iteration is given by a function call that returns
4001 -- a container, the finalization actions have been saved in the
4002 -- Condition_Actions of the iterator. Insert them now at the head of
4005 if Present
(Condition_Actions
(Isc
)) then
4006 Insert_List_Before
(N
, Condition_Actions
(Isc
));
4009 Rewrite
(N
, New_Loop
);
4011 end Expand_Iterator_Loop_Over_Container
;
4013 -----------------------------
4014 -- Expand_N_Loop_Statement --
4015 -----------------------------
4017 -- 1. Remove null loop entirely
4018 -- 2. Deal with while condition for C/Fortran boolean
4019 -- 3. Deal with loops with a non-standard enumeration type range
4020 -- 4. Deal with while loops where Condition_Actions is set
4021 -- 5. Deal with loops over predicated subtypes
4022 -- 6. Deal with loops with iterators over arrays and containers
4023 -- 7. Insert polling call if required
4025 procedure Expand_N_Loop_Statement
(N
: Node_Id
) is
4026 Loc
: constant Source_Ptr
:= Sloc
(N
);
4027 Scheme
: constant Node_Id
:= Iteration_Scheme
(N
);
4033 if Is_Null_Loop
(N
) then
4034 Rewrite
(N
, Make_Null_Statement
(Loc
));
4038 -- Deal with condition for C/Fortran Boolean
4040 if Present
(Scheme
) then
4041 Adjust_Condition
(Condition
(Scheme
));
4044 -- Generate polling call
4046 if Is_Non_Empty_List
(Statements
(N
)) then
4047 Generate_Poll_Call
(First
(Statements
(N
)));
4050 -- Nothing more to do for plain loop with no iteration scheme
4055 -- Case of for loop (Loop_Parameter_Specification present)
4057 -- Note: we do not have to worry about validity checking of the for loop
4058 -- range bounds here, since they were frozen with constant declarations
4059 -- and it is during that process that the validity checking is done.
4061 elsif Present
(Loop_Parameter_Specification
(Scheme
)) then
4063 LPS
: constant Node_Id
:=
4064 Loop_Parameter_Specification
(Scheme
);
4065 Loop_Id
: constant Entity_Id
:= Defining_Identifier
(LPS
);
4066 Ltype
: constant Entity_Id
:= Etype
(Loop_Id
);
4067 Btype
: constant Entity_Id
:= Base_Type
(Ltype
);
4073 -- Deal with loop over predicates
4075 if Is_Discrete_Type
(Ltype
)
4076 and then Present
(Predicate_Function
(Ltype
))
4078 Expand_Predicated_Loop
(N
);
4080 -- Handle the case where we have a for loop with the range type
4081 -- being an enumeration type with non-standard representation.
4082 -- In this case we expand:
4084 -- for x in [reverse] a .. b loop
4090 -- for xP in [reverse] integer
4091 -- range etype'Pos (a) .. etype'Pos (b)
4094 -- x : constant etype := Pos_To_Rep (xP);
4100 elsif Is_Enumeration_Type
(Btype
)
4101 and then Present
(Enum_Pos_To_Rep
(Btype
))
4104 Make_Defining_Identifier
(Loc
,
4105 Chars
=> New_External_Name
(Chars
(Loop_Id
), 'P'));
4107 -- If the type has a contiguous representation, successive
4108 -- values can be generated as offsets from the first literal.
4110 if Has_Contiguous_Rep
(Btype
) then
4112 Unchecked_Convert_To
(Btype
,
4115 Make_Integer_Literal
(Loc
,
4116 Enumeration_Rep
(First_Literal
(Btype
))),
4117 Right_Opnd
=> New_Occurrence_Of
(New_Id
, Loc
)));
4119 -- Use the constructed array Enum_Pos_To_Rep
4122 Make_Indexed_Component
(Loc
,
4124 New_Occurrence_Of
(Enum_Pos_To_Rep
(Btype
), Loc
),
4126 New_List
(New_Occurrence_Of
(New_Id
, Loc
)));
4129 -- Build declaration for loop identifier
4133 Make_Object_Declaration
(Loc
,
4134 Defining_Identifier
=> Loop_Id
,
4135 Constant_Present
=> True,
4136 Object_Definition
=> New_Occurrence_Of
(Ltype
, Loc
),
4137 Expression
=> Expr
));
4140 Make_Loop_Statement
(Loc
,
4141 Identifier
=> Identifier
(N
),
4144 Make_Iteration_Scheme
(Loc
,
4145 Loop_Parameter_Specification
=>
4146 Make_Loop_Parameter_Specification
(Loc
,
4147 Defining_Identifier
=> New_Id
,
4148 Reverse_Present
=> Reverse_Present
(LPS
),
4150 Discrete_Subtype_Definition
=>
4151 Make_Subtype_Indication
(Loc
,
4154 New_Occurrence_Of
(Standard_Natural
, Loc
),
4157 Make_Range_Constraint
(Loc
,
4162 Make_Attribute_Reference
(Loc
,
4164 New_Occurrence_Of
(Btype
, Loc
),
4166 Attribute_Name
=> Name_Pos
,
4168 Expressions
=> New_List
(
4170 (Type_Low_Bound
(Ltype
)))),
4173 Make_Attribute_Reference
(Loc
,
4175 New_Occurrence_Of
(Btype
, Loc
),
4177 Attribute_Name
=> Name_Pos
,
4179 Expressions
=> New_List
(
4184 Statements
=> New_List
(
4185 Make_Block_Statement
(Loc
,
4186 Declarations
=> Decls
,
4187 Handled_Statement_Sequence
=>
4188 Make_Handled_Sequence_Of_Statements
(Loc
,
4189 Statements
=> Statements
(N
)))),
4191 End_Label
=> End_Label
(N
)));
4193 -- The loop parameter's entity must be removed from the loop
4194 -- scope's entity list and rendered invisible, since it will
4195 -- now be located in the new block scope. Any other entities
4196 -- already associated with the loop scope, such as the loop
4197 -- parameter's subtype, will remain there.
4199 -- In an element loop, the loop will contain a declaration for
4200 -- a cursor variable; otherwise the loop id is the first entity
4201 -- in the scope constructed for the loop.
4203 if Comes_From_Source
(Loop_Id
) then
4204 pragma Assert
(First_Entity
(Scope
(Loop_Id
)) = Loop_Id
);
4208 Set_First_Entity
(Scope
(Loop_Id
), Next_Entity
(Loop_Id
));
4209 Remove_Homonym
(Loop_Id
);
4211 if Last_Entity
(Scope
(Loop_Id
)) = Loop_Id
then
4212 Set_Last_Entity
(Scope
(Loop_Id
), Empty
);
4217 -- Nothing to do with other cases of for loops
4224 -- Second case, if we have a while loop with Condition_Actions set, then
4225 -- we change it into a plain loop:
4234 -- <<condition actions>>
4239 elsif Present
(Scheme
)
4240 and then Present
(Condition_Actions
(Scheme
))
4241 and then Present
(Condition
(Scheme
))
4248 Make_Exit_Statement
(Sloc
(Condition
(Scheme
)),
4250 Make_Op_Not
(Sloc
(Condition
(Scheme
)),
4251 Right_Opnd
=> Condition
(Scheme
)));
4253 Prepend
(ES
, Statements
(N
));
4254 Insert_List_Before
(ES
, Condition_Actions
(Scheme
));
4256 -- This is not an implicit loop, since it is generated in response
4257 -- to the loop statement being processed. If this is itself
4258 -- implicit, the restriction has already been checked. If not,
4259 -- it is an explicit loop.
4262 Make_Loop_Statement
(Sloc
(N
),
4263 Identifier
=> Identifier
(N
),
4264 Statements
=> Statements
(N
),
4265 End_Label
=> End_Label
(N
)));
4270 -- Here to deal with iterator case
4272 elsif Present
(Scheme
)
4273 and then Present
(Iterator_Specification
(Scheme
))
4275 Expand_Iterator_Loop
(N
);
4277 -- An iterator loop may generate renaming declarations for elements
4278 -- that require debug information. This is the case in particular
4279 -- with element iterators, where debug information must be generated
4280 -- for the temporary that holds the element value. These temporaries
4281 -- are created within a transient block whose local declarations are
4282 -- transferred to the loop, which now has non-trivial local objects.
4284 if Nkind
(N
) = N_Loop_Statement
4285 and then Present
(Identifier
(N
))
4287 Qualify_Entity_Names
(N
);
4291 -- When the iteration scheme mentiones attribute 'Loop_Entry, the loop
4292 -- is transformed into a conditional block where the original loop is
4293 -- the sole statement. Inspect the statements of the nested loop for
4294 -- controlled objects.
4298 if Subject_To_Loop_Entry_Attributes
(Stmt
) then
4299 Stmt
:= Find_Loop_In_Conditional_Block
(Stmt
);
4302 Process_Statements_For_Controlled_Objects
(Stmt
);
4303 end Expand_N_Loop_Statement
;
4305 ----------------------------
4306 -- Expand_Predicated_Loop --
4307 ----------------------------
4309 -- Note: the expander can handle generation of loops over predicated
4310 -- subtypes for both the dynamic and static cases. Depending on what
4311 -- we decide is allowed in Ada 2012 mode and/or extensions allowed
4312 -- mode, the semantic analyzer may disallow one or both forms.
4314 procedure Expand_Predicated_Loop
(N
: Node_Id
) is
4315 Loc
: constant Source_Ptr
:= Sloc
(N
);
4316 Isc
: constant Node_Id
:= Iteration_Scheme
(N
);
4317 LPS
: constant Node_Id
:= Loop_Parameter_Specification
(Isc
);
4318 Loop_Id
: constant Entity_Id
:= Defining_Identifier
(LPS
);
4319 Ltype
: constant Entity_Id
:= Etype
(Loop_Id
);
4320 Stat
: constant List_Id
:= Static_Discrete_Predicate
(Ltype
);
4321 Stmts
: constant List_Id
:= Statements
(N
);
4324 -- Case of iteration over non-static predicate, should not be possible
4325 -- since this is not allowed by the semantics and should have been
4326 -- caught during analysis of the loop statement.
4329 raise Program_Error
;
4331 -- If the predicate list is empty, that corresponds to a predicate of
4332 -- False, in which case the loop won't run at all, and we rewrite the
4333 -- entire loop as a null statement.
4335 elsif Is_Empty_List
(Stat
) then
4336 Rewrite
(N
, Make_Null_Statement
(Loc
));
4339 -- For expansion over a static predicate we generate the following
4342 -- J : Ltype := min-val;
4347 -- when endpoint => J := startpoint;
4348 -- when endpoint => J := startpoint;
4350 -- when max-val => exit;
4351 -- when others => J := Lval'Succ (J);
4356 -- with min-val replaced by max-val and Succ replaced by Pred if the
4357 -- loop parameter specification carries a Reverse indicator.
4359 -- To make this a little clearer, let's take a specific example:
4361 -- type Int is range 1 .. 10;
4362 -- subtype StaticP is Int with
4363 -- predicate => StaticP in 3 | 10 | 5 .. 7;
4365 -- for L in StaticP loop
4366 -- Put_Line ("static:" & J'Img);
4369 -- In this case, the loop is transformed into
4376 -- when 3 => J := 5;
4377 -- when 7 => J := 10;
4379 -- when others => J := L'Succ (J);
4385 Static_Predicate
: declare
4392 function Lo_Val
(N
: Node_Id
) return Node_Id
;
4393 -- Given static expression or static range, returns an identifier
4394 -- whose value is the low bound of the expression value or range.
4396 function Hi_Val
(N
: Node_Id
) return Node_Id
;
4397 -- Given static expression or static range, returns an identifier
4398 -- whose value is the high bound of the expression value or range.
4404 function Hi_Val
(N
: Node_Id
) return Node_Id
is
4406 if Is_OK_Static_Expression
(N
) then
4407 return New_Copy
(N
);
4409 pragma Assert
(Nkind
(N
) = N_Range
);
4410 return New_Copy
(High_Bound
(N
));
4418 function Lo_Val
(N
: Node_Id
) return Node_Id
is
4420 if Is_OK_Static_Expression
(N
) then
4421 return New_Copy
(N
);
4423 pragma Assert
(Nkind
(N
) = N_Range
);
4424 return New_Copy
(Low_Bound
(N
));
4428 -- Start of processing for Static_Predicate
4431 -- Convert loop identifier to normal variable and reanalyze it so
4432 -- that this conversion works. We have to use the same defining
4433 -- identifier, since there may be references in the loop body.
4435 Set_Analyzed
(Loop_Id
, False);
4436 Set_Ekind
(Loop_Id
, E_Variable
);
4438 -- In most loops the loop variable is assigned in various
4439 -- alternatives in the body. However, in the rare case when
4440 -- the range specifies a single element, the loop variable
4441 -- may trigger a spurious warning that is could be constant.
4442 -- This warning might as well be suppressed.
4444 Set_Warnings_Off
(Loop_Id
);
4446 -- Loop to create branches of case statement
4450 if Reverse_Present
(LPS
) then
4452 -- Initial value is largest value in predicate.
4455 Make_Object_Declaration
(Loc
,
4456 Defining_Identifier
=> Loop_Id
,
4457 Object_Definition
=> New_Occurrence_Of
(Ltype
, Loc
),
4458 Expression
=> Hi_Val
(Last
(Stat
)));
4461 while Present
(P
) loop
4462 if No
(Prev
(P
)) then
4463 S
:= Make_Exit_Statement
(Loc
);
4466 Make_Assignment_Statement
(Loc
,
4467 Name
=> New_Occurrence_Of
(Loop_Id
, Loc
),
4468 Expression
=> Hi_Val
(Prev
(P
)));
4469 Set_Suppress_Assignment_Checks
(S
);
4473 Make_Case_Statement_Alternative
(Loc
,
4474 Statements
=> New_List
(S
),
4475 Discrete_Choices
=> New_List
(Lo_Val
(P
))));
4482 -- Initial value is smallest value in predicate.
4485 Make_Object_Declaration
(Loc
,
4486 Defining_Identifier
=> Loop_Id
,
4487 Object_Definition
=> New_Occurrence_Of
(Ltype
, Loc
),
4488 Expression
=> Lo_Val
(First
(Stat
)));
4491 while Present
(P
) loop
4492 if No
(Next
(P
)) then
4493 S
:= Make_Exit_Statement
(Loc
);
4496 Make_Assignment_Statement
(Loc
,
4497 Name
=> New_Occurrence_Of
(Loop_Id
, Loc
),
4498 Expression
=> Lo_Val
(Next
(P
)));
4499 Set_Suppress_Assignment_Checks
(S
);
4503 Make_Case_Statement_Alternative
(Loc
,
4504 Statements
=> New_List
(S
),
4505 Discrete_Choices
=> New_List
(Hi_Val
(P
))));
4511 -- Add others choice
4514 Name_Next
: Name_Id
;
4517 if Reverse_Present
(LPS
) then
4518 Name_Next
:= Name_Pred
;
4520 Name_Next
:= Name_Succ
;
4524 Make_Assignment_Statement
(Loc
,
4525 Name
=> New_Occurrence_Of
(Loop_Id
, Loc
),
4527 Make_Attribute_Reference
(Loc
,
4528 Prefix
=> New_Occurrence_Of
(Ltype
, Loc
),
4529 Attribute_Name
=> Name_Next
,
4530 Expressions
=> New_List
(
4531 New_Occurrence_Of
(Loop_Id
, Loc
))));
4532 Set_Suppress_Assignment_Checks
(S
);
4536 Make_Case_Statement_Alternative
(Loc
,
4537 Discrete_Choices
=> New_List
(Make_Others_Choice
(Loc
)),
4538 Statements
=> New_List
(S
)));
4540 -- Construct case statement and append to body statements
4543 Make_Case_Statement
(Loc
,
4544 Expression
=> New_Occurrence_Of
(Loop_Id
, Loc
),
4545 Alternatives
=> Alts
);
4546 Append_To
(Stmts
, Cstm
);
4550 Set_Suppress_Assignment_Checks
(D
);
4553 Make_Block_Statement
(Loc
,
4554 Declarations
=> New_List
(D
),
4555 Handled_Statement_Sequence
=>
4556 Make_Handled_Sequence_Of_Statements
(Loc
,
4557 Statements
=> New_List
(
4558 Make_Loop_Statement
(Loc
,
4559 Statements
=> Stmts
,
4560 End_Label
=> Empty
)))));
4563 end Static_Predicate
;
4565 end Expand_Predicated_Loop
;
4567 ------------------------------
4568 -- Make_Tag_Ctrl_Assignment --
4569 ------------------------------
4571 function Make_Tag_Ctrl_Assignment
(N
: Node_Id
) return List_Id
is
4572 Asn
: constant Node_Id
:= Relocate_Node
(N
);
4573 L
: constant Node_Id
:= Name
(N
);
4574 Loc
: constant Source_Ptr
:= Sloc
(N
);
4575 Res
: constant List_Id
:= New_List
;
4576 T
: constant Entity_Id
:= Underlying_Type
(Etype
(L
));
4578 Comp_Asn
: constant Boolean := Is_Fully_Repped_Tagged_Type
(T
);
4579 Ctrl_Act
: constant Boolean := Needs_Finalization
(T
)
4580 and then not No_Ctrl_Actions
(N
);
4581 Save_Tag
: constant Boolean := Is_Tagged_Type
(T
)
4582 and then not Comp_Asn
4583 and then not No_Ctrl_Actions
(N
)
4584 and then Tagged_Type_Expansion
;
4585 -- Tags are not saved and restored when VM_Target because VM tags are
4586 -- represented implicitly in objects.
4588 Next_Id
: Entity_Id
;
4589 Prev_Id
: Entity_Id
;
4593 -- Finalize the target of the assignment when controlled
4595 -- We have two exceptions here:
4597 -- 1. If we are in an init proc since it is an initialization more
4598 -- than an assignment.
4600 -- 2. If the left-hand side is a temporary that was not initialized
4601 -- (or the parent part of a temporary since it is the case in
4602 -- extension aggregates). Such a temporary does not come from
4603 -- source. We must examine the original node for the prefix, because
4604 -- it may be a component of an entry formal, in which case it has
4605 -- been rewritten and does not appear to come from source either.
4607 -- Case of init proc
4609 if not Ctrl_Act
then
4612 -- The left hand side is an uninitialized temporary object
4614 elsif Nkind
(L
) = N_Type_Conversion
4615 and then Is_Entity_Name
(Expression
(L
))
4616 and then Nkind
(Parent
(Entity
(Expression
(L
)))) =
4617 N_Object_Declaration
4618 and then No_Initialization
(Parent
(Entity
(Expression
(L
))))
4625 (Obj_Ref
=> Duplicate_Subexpr_No_Checks
(L
),
4629 -- Save the Tag in a local variable Tag_Id
4632 Tag_Id
:= Make_Temporary
(Loc
, 'A');
4635 Make_Object_Declaration
(Loc
,
4636 Defining_Identifier
=> Tag_Id
,
4637 Object_Definition
=> New_Occurrence_Of
(RTE
(RE_Tag
), Loc
),
4639 Make_Selected_Component
(Loc
,
4640 Prefix
=> Duplicate_Subexpr_No_Checks
(L
),
4642 New_Occurrence_Of
(First_Tag_Component
(T
), Loc
))));
4644 -- Otherwise Tag_Id is not used
4650 -- Save the Prev and Next fields on .NET/JVM. This is not needed on non
4651 -- VM targets since the fields are not part of the object.
4653 if VM_Target
/= No_VM
4654 and then Is_Controlled
(T
)
4656 Prev_Id
:= Make_Temporary
(Loc
, 'P');
4657 Next_Id
:= Make_Temporary
(Loc
, 'N');
4660 -- Pnn : Root_Controlled_Ptr := Root_Controlled (L).Prev;
4663 Make_Object_Declaration
(Loc
,
4664 Defining_Identifier
=> Prev_Id
,
4665 Object_Definition
=>
4666 New_Occurrence_Of
(RTE
(RE_Root_Controlled_Ptr
), Loc
),
4668 Make_Selected_Component
(Loc
,
4670 Unchecked_Convert_To
4671 (RTE
(RE_Root_Controlled
), New_Copy_Tree
(L
)),
4673 Make_Identifier
(Loc
, Name_Prev
))));
4676 -- Nnn : Root_Controlled_Ptr := Root_Controlled (L).Next;
4679 Make_Object_Declaration
(Loc
,
4680 Defining_Identifier
=> Next_Id
,
4681 Object_Definition
=>
4682 New_Occurrence_Of
(RTE
(RE_Root_Controlled_Ptr
), Loc
),
4684 Make_Selected_Component
(Loc
,
4686 Unchecked_Convert_To
4687 (RTE
(RE_Root_Controlled
), New_Copy_Tree
(L
)),
4689 Make_Identifier
(Loc
, Name_Next
))));
4692 -- If the tagged type has a full rep clause, expand the assignment into
4693 -- component-wise assignments. Mark the node as unanalyzed in order to
4694 -- generate the proper code and propagate this scenario by setting a
4695 -- flag to avoid infinite recursion.
4698 Set_Analyzed
(Asn
, False);
4699 Set_Componentwise_Assignment
(Asn
, True);
4702 Append_To
(Res
, Asn
);
4708 Make_Assignment_Statement
(Loc
,
4710 Make_Selected_Component
(Loc
,
4711 Prefix
=> Duplicate_Subexpr_No_Checks
(L
),
4713 New_Occurrence_Of
(First_Tag_Component
(T
), Loc
)),
4714 Expression
=> New_Occurrence_Of
(Tag_Id
, Loc
)));
4717 -- Restore the Prev and Next fields on .NET/JVM
4719 if VM_Target
/= No_VM
4720 and then Is_Controlled
(T
)
4723 -- Root_Controlled (L).Prev := Prev_Id;
4726 Make_Assignment_Statement
(Loc
,
4728 Make_Selected_Component
(Loc
,
4730 Unchecked_Convert_To
4731 (RTE
(RE_Root_Controlled
), New_Copy_Tree
(L
)),
4733 Make_Identifier
(Loc
, Name_Prev
)),
4734 Expression
=> New_Occurrence_Of
(Prev_Id
, Loc
)));
4737 -- Root_Controlled (L).Next := Next_Id;
4740 Make_Assignment_Statement
(Loc
,
4742 Make_Selected_Component
(Loc
,
4744 Unchecked_Convert_To
4745 (RTE
(RE_Root_Controlled
), New_Copy_Tree
(L
)),
4746 Selector_Name
=> Make_Identifier
(Loc
, Name_Next
)),
4747 Expression
=> New_Occurrence_Of
(Next_Id
, Loc
)));
4750 -- Adjust the target after the assignment when controlled (not in the
4751 -- init proc since it is an initialization more than an assignment).
4756 (Obj_Ref
=> Duplicate_Subexpr_Move_Checks
(L
),
4764 -- Could use comment here ???
4766 when RE_Not_Available
=>
4768 end Make_Tag_Ctrl_Assignment
;