File : sem_res.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2016, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
26 with Atree; use Atree;
27 with Checks; use Checks;
28 with Debug; use Debug;
29 with Debug_A; use Debug_A;
30 with Einfo; use Einfo;
31 with Errout; use Errout;
32 with Expander; use Expander;
33 with Exp_Disp; use Exp_Disp;
34 with Exp_Ch6; use Exp_Ch6;
35 with Exp_Ch7; use Exp_Ch7;
36 with Exp_Tss; use Exp_Tss;
37 with Exp_Util; use Exp_Util;
38 with Fname; use Fname;
39 with Freeze; use Freeze;
40 with Ghost; use Ghost;
41 with Inline; use Inline;
42 with Itypes; use Itypes;
43 with Lib; use Lib;
44 with Lib.Xref; use Lib.Xref;
45 with Namet; use Namet;
46 with Nmake; use Nmake;
47 with Nlists; use Nlists;
48 with Opt; use Opt;
49 with Output; use Output;
50 with Par_SCO; use Par_SCO;
51 with Restrict; use Restrict;
52 with Rident; use Rident;
53 with Rtsfind; use Rtsfind;
54 with Sem; use Sem;
55 with Sem_Aux; use Sem_Aux;
56 with Sem_Aggr; use Sem_Aggr;
57 with Sem_Attr; use Sem_Attr;
58 with Sem_Cat; use Sem_Cat;
59 with Sem_Ch4; use Sem_Ch4;
60 with Sem_Ch3; use Sem_Ch3;
61 with Sem_Ch6; use Sem_Ch6;
62 with Sem_Ch8; use Sem_Ch8;
63 with Sem_Ch13; use Sem_Ch13;
64 with Sem_Dim; use Sem_Dim;
65 with Sem_Disp; use Sem_Disp;
66 with Sem_Dist; use Sem_Dist;
67 with Sem_Elim; use Sem_Elim;
68 with Sem_Elab; use Sem_Elab;
69 with Sem_Eval; use Sem_Eval;
70 with Sem_Intr; use Sem_Intr;
71 with Sem_Util; use Sem_Util;
72 with Targparm; use Targparm;
73 with Sem_Type; use Sem_Type;
74 with Sem_Warn; use Sem_Warn;
75 with Sinfo; use Sinfo;
76 with Sinfo.CN; use Sinfo.CN;
77 with Snames; use Snames;
78 with Stand; use Stand;
79 with Stringt; use Stringt;
80 with Style; use Style;
81 with Tbuild; use Tbuild;
82 with Uintp; use Uintp;
83 with Urealp; use Urealp;
84
85 package body Sem_Res is
86
87 -----------------------
88 -- Local Subprograms --
89 -----------------------
90
91 -- Second pass (top-down) type checking and overload resolution procedures
92 -- Typ is the type required by context. These procedures propagate the
93 -- type information recursively to the descendants of N. If the node is not
94 -- overloaded, its Etype is established in the first pass. If overloaded,
95 -- the Resolve routines set the correct type. For arithmetic operators, the
96 -- Etype is the base type of the context.
97
98 -- Note that Resolve_Attribute is separated off in Sem_Attr
99
100 procedure Check_Discriminant_Use (N : Node_Id);
101 -- Enforce the restrictions on the use of discriminants when constraining
102 -- a component of a discriminated type (record or concurrent type).
103
104 procedure Check_For_Visible_Operator (N : Node_Id; T : Entity_Id);
105 -- Given a node for an operator associated with type T, check that the
106 -- operator is visible. Operators all of whose operands are universal must
107 -- be checked for visibility during resolution because their type is not
108 -- determinable based on their operands.
109
110 procedure Check_Fully_Declared_Prefix
111 (Typ : Entity_Id;
112 Pref : Node_Id);
113 -- Check that the type of the prefix of a dereference is not incomplete
114
115 function Check_Infinite_Recursion (N : Node_Id) return Boolean;
116 -- Given a call node, N, which is known to occur immediately within the
117 -- subprogram being called, determines whether it is a detectable case of
118 -- an infinite recursion, and if so, outputs appropriate messages. Returns
119 -- True if an infinite recursion is detected, and False otherwise.
120
121 procedure Check_Initialization_Call (N : Entity_Id; Nam : Entity_Id);
122 -- If the type of the object being initialized uses the secondary stack
123 -- directly or indirectly, create a transient scope for the call to the
124 -- init proc. This is because we do not create transient scopes for the
125 -- initialization of individual components within the init proc itself.
126 -- Could be optimized away perhaps?
127
128 procedure Check_No_Direct_Boolean_Operators (N : Node_Id);
129 -- N is the node for a logical operator. If the operator is predefined, and
130 -- the root type of the operands is Standard.Boolean, then a check is made
131 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
132 -- the style check for Style_Check_Boolean_And_Or.
133
134 function Is_Atomic_Ref_With_Address (N : Node_Id) return Boolean;
135 -- N is either an indexed component or a selected component. This function
136 -- returns true if the prefix refers to an object that has an address
137 -- clause (the case in which we may want to issue a warning).
138
139 function Is_Definite_Access_Type (E : Entity_Id) return Boolean;
140 -- Determine whether E is an access type declared by an access declaration,
141 -- and not an (anonymous) allocator type.
142
143 function Is_Predefined_Op (Nam : Entity_Id) return Boolean;
144 -- Utility to check whether the entity for an operator is a predefined
145 -- operator, in which case the expression is left as an operator in the
146 -- tree (else it is rewritten into a call). An instance of an intrinsic
147 -- conversion operation may be given an operator name, but is not treated
148 -- like an operator. Note that an operator that is an imported back-end
149 -- builtin has convention Intrinsic, but is expected to be rewritten into
150 -- a call, so such an operator is not treated as predefined by this
151 -- predicate.
152
153 procedure Replace_Actual_Discriminants (N : Node_Id; Default : Node_Id);
154 -- If a default expression in entry call N depends on the discriminants
155 -- of the task, it must be replaced with a reference to the discriminant
156 -- of the task being called.
157
158 procedure Resolve_Op_Concat_Arg
159 (N : Node_Id;
160 Arg : Node_Id;
161 Typ : Entity_Id;
162 Is_Comp : Boolean);
163 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
164 -- concatenation operator. The operand is either of the array type or of
165 -- the component type. If the operand is an aggregate, and the component
166 -- type is composite, this is ambiguous if component type has aggregates.
167
168 procedure Resolve_Op_Concat_First (N : Node_Id; Typ : Entity_Id);
169 -- Does the first part of the work of Resolve_Op_Concat
170
171 procedure Resolve_Op_Concat_Rest (N : Node_Id; Typ : Entity_Id);
172 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
173 -- has been resolved. See Resolve_Op_Concat for details.
174
175 procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id);
176 procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id);
177 procedure Resolve_Call (N : Node_Id; Typ : Entity_Id);
178 procedure Resolve_Case_Expression (N : Node_Id; Typ : Entity_Id);
179 procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id);
180 procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id);
181 procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id);
182 procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id);
183 procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id);
184 procedure Resolve_Expression_With_Actions (N : Node_Id; Typ : Entity_Id);
185 procedure Resolve_If_Expression (N : Node_Id; Typ : Entity_Id);
186 procedure Resolve_Generalized_Indexing (N : Node_Id; Typ : Entity_Id);
187 procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id);
188 procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id);
189 procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id);
190 procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id);
191 procedure Resolve_Null (N : Node_Id; Typ : Entity_Id);
192 procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id);
193 procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id);
194 procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id);
195 procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id);
196 procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id);
197 procedure Resolve_Raise_Expression (N : Node_Id; Typ : Entity_Id);
198 procedure Resolve_Range (N : Node_Id; Typ : Entity_Id);
199 procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id);
200 procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id);
201 procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id);
202 procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id);
203 procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id);
204 procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id);
205 procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id);
206 procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id);
207 procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id);
208 procedure Resolve_Unchecked_Expression (N : Node_Id; Typ : Entity_Id);
209 procedure Resolve_Unchecked_Type_Conversion (N : Node_Id; Typ : Entity_Id);
210
211 function Operator_Kind
212 (Op_Name : Name_Id;
213 Is_Binary : Boolean) return Node_Kind;
214 -- Utility to map the name of an operator into the corresponding Node. Used
215 -- by other node rewriting procedures.
216
217 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id);
218 -- Resolve actuals of call, and add default expressions for missing ones.
219 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
220 -- called subprogram.
221
222 procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id);
223 -- Called from Resolve_Call, when the prefix denotes an entry or element
224 -- of entry family. Actuals are resolved as for subprograms, and the node
225 -- is rebuilt as an entry call. Also called for protected operations. Typ
226 -- is the context type, which is used when the operation is a protected
227 -- function with no arguments, and the return value is indexed.
228
229 procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id);
230 -- A call to a user-defined intrinsic operator is rewritten as a call to
231 -- the corresponding predefined operator, with suitable conversions. Note
232 -- that this applies only for intrinsic operators that denote predefined
233 -- operators, not ones that are intrinsic imports of back-end builtins.
234
235 procedure Resolve_Intrinsic_Unary_Operator (N : Node_Id; Typ : Entity_Id);
236 -- Ditto, for arithmetic unary operators
237
238 procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id);
239 -- If an operator node resolves to a call to a user-defined operator,
240 -- rewrite the node as a function call.
241
242 procedure Make_Call_Into_Operator
243 (N : Node_Id;
244 Typ : Entity_Id;
245 Op_Id : Entity_Id);
246 -- Inverse transformation: if an operator is given in functional notation,
247 -- then after resolving the node, transform into an operator node, so that
248 -- operands are resolved properly. Recall that predefined operators do not
249 -- have a full signature and special resolution rules apply.
250
251 procedure Rewrite_Renamed_Operator
252 (N : Node_Id;
253 Op : Entity_Id;
254 Typ : Entity_Id);
255 -- An operator can rename another, e.g. in an instantiation. In that
256 -- case, the proper operator node must be constructed and resolved.
257
258 procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id);
259 -- The String_Literal_Subtype is built for all strings that are not
260 -- operands of a static concatenation operation. If the argument is not
261 -- a N_String_Literal node, then the call has no effect.
262
263 procedure Set_Slice_Subtype (N : Node_Id);
264 -- Build subtype of array type, with the range specified by the slice
265
266 procedure Simplify_Type_Conversion (N : Node_Id);
267 -- Called after N has been resolved and evaluated, but before range checks
268 -- have been applied. Currently simplifies a combination of floating-point
269 -- to integer conversion and Rounding or Truncation attribute.
270
271 function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id;
272 -- A universal_fixed expression in an universal context is unambiguous if
273 -- there is only one applicable fixed point type. Determining whether there
274 -- is only one requires a search over all visible entities, and happens
275 -- only in very pathological cases (see 6115-006).
276
277 -------------------------
278 -- Ambiguous_Character --
279 -------------------------
280
281 procedure Ambiguous_Character (C : Node_Id) is
282 E : Entity_Id;
283
284 begin
285 if Nkind (C) = N_Character_Literal then
286 Error_Msg_N ("ambiguous character literal", C);
287
288 -- First the ones in Standard
289
290 Error_Msg_N ("\\possible interpretation: Character!", C);
291 Error_Msg_N ("\\possible interpretation: Wide_Character!", C);
292
293 -- Include Wide_Wide_Character in Ada 2005 mode
294
295 if Ada_Version >= Ada_2005 then
296 Error_Msg_N ("\\possible interpretation: Wide_Wide_Character!", C);
297 end if;
298
299 -- Now any other types that match
300
301 E := Current_Entity (C);
302 while Present (E) loop
303 Error_Msg_NE ("\\possible interpretation:}!", C, Etype (E));
304 E := Homonym (E);
305 end loop;
306 end if;
307 end Ambiguous_Character;
308
309 -------------------------
310 -- Analyze_And_Resolve --
311 -------------------------
312
313 procedure Analyze_And_Resolve (N : Node_Id) is
314 begin
315 Analyze (N);
316 Resolve (N);
317 end Analyze_And_Resolve;
318
319 procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id) is
320 begin
321 Analyze (N);
322 Resolve (N, Typ);
323 end Analyze_And_Resolve;
324
325 -- Versions with check(s) suppressed
326
327 procedure Analyze_And_Resolve
328 (N : Node_Id;
329 Typ : Entity_Id;
330 Suppress : Check_Id)
331 is
332 Scop : constant Entity_Id := Current_Scope;
333
334 begin
335 if Suppress = All_Checks then
336 declare
337 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
338 begin
339 Scope_Suppress.Suppress := (others => True);
340 Analyze_And_Resolve (N, Typ);
341 Scope_Suppress.Suppress := Sva;
342 end;
343
344 else
345 declare
346 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
347 begin
348 Scope_Suppress.Suppress (Suppress) := True;
349 Analyze_And_Resolve (N, Typ);
350 Scope_Suppress.Suppress (Suppress) := Svg;
351 end;
352 end if;
353
354 if Current_Scope /= Scop
355 and then Scope_Is_Transient
356 then
357 -- This can only happen if a transient scope was created for an inner
358 -- expression, which will be removed upon completion of the analysis
359 -- of an enclosing construct. The transient scope must have the
360 -- suppress status of the enclosing environment, not of this Analyze
361 -- call.
362
363 Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress :=
364 Scope_Suppress;
365 end if;
366 end Analyze_And_Resolve;
367
368 procedure Analyze_And_Resolve
369 (N : Node_Id;
370 Suppress : Check_Id)
371 is
372 Scop : constant Entity_Id := Current_Scope;
373
374 begin
375 if Suppress = All_Checks then
376 declare
377 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
378 begin
379 Scope_Suppress.Suppress := (others => True);
380 Analyze_And_Resolve (N);
381 Scope_Suppress.Suppress := Sva;
382 end;
383
384 else
385 declare
386 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
387 begin
388 Scope_Suppress.Suppress (Suppress) := True;
389 Analyze_And_Resolve (N);
390 Scope_Suppress.Suppress (Suppress) := Svg;
391 end;
392 end if;
393
394 if Current_Scope /= Scop and then Scope_Is_Transient then
395 Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress :=
396 Scope_Suppress;
397 end if;
398 end Analyze_And_Resolve;
399
400 ----------------------------
401 -- Check_Discriminant_Use --
402 ----------------------------
403
404 procedure Check_Discriminant_Use (N : Node_Id) is
405 PN : constant Node_Id := Parent (N);
406 Disc : constant Entity_Id := Entity (N);
407 P : Node_Id;
408 D : Node_Id;
409
410 begin
411 -- Any use in a spec-expression is legal
412
413 if In_Spec_Expression then
414 null;
415
416 elsif Nkind (PN) = N_Range then
417
418 -- Discriminant cannot be used to constrain a scalar type
419
420 P := Parent (PN);
421
422 if Nkind (P) = N_Range_Constraint
423 and then Nkind (Parent (P)) = N_Subtype_Indication
424 and then Nkind (Parent (Parent (P))) = N_Component_Definition
425 then
426 Error_Msg_N ("discriminant cannot constrain scalar type", N);
427
428 elsif Nkind (P) = N_Index_Or_Discriminant_Constraint then
429
430 -- The following check catches the unusual case where a
431 -- discriminant appears within an index constraint that is part
432 -- of a larger expression within a constraint on a component,
433 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
434 -- check case of record components, and note that a similar check
435 -- should also apply in the case of discriminant constraints
436 -- below. ???
437
438 -- Note that the check for N_Subtype_Declaration below is to
439 -- detect the valid use of discriminants in the constraints of a
440 -- subtype declaration when this subtype declaration appears
441 -- inside the scope of a record type (which is syntactically
442 -- illegal, but which may be created as part of derived type
443 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
444 -- for more info.
445
446 if Ekind (Current_Scope) = E_Record_Type
447 and then Scope (Disc) = Current_Scope
448 and then not
449 (Nkind (Parent (P)) = N_Subtype_Indication
450 and then
451 Nkind_In (Parent (Parent (P)), N_Component_Definition,
452 N_Subtype_Declaration)
453 and then Paren_Count (N) = 0)
454 then
455 Error_Msg_N
456 ("discriminant must appear alone in component constraint", N);
457 return;
458 end if;
459
460 -- Detect a common error:
461
462 -- type R (D : Positive := 100) is record
463 -- Name : String (1 .. D);
464 -- end record;
465
466 -- The default value causes an object of type R to be allocated
467 -- with room for Positive'Last characters. The RM does not mandate
468 -- the allocation of the maximum size, but that is what GNAT does
469 -- so we should warn the programmer that there is a problem.
470
471 Check_Large : declare
472 SI : Node_Id;
473 T : Entity_Id;
474 TB : Node_Id;
475 CB : Entity_Id;
476
477 function Large_Storage_Type (T : Entity_Id) return Boolean;
478 -- Return True if type T has a large enough range that any
479 -- array whose index type covered the whole range of the type
480 -- would likely raise Storage_Error.
481
482 ------------------------
483 -- Large_Storage_Type --
484 ------------------------
485
486 function Large_Storage_Type (T : Entity_Id) return Boolean is
487 begin
488 -- The type is considered large if its bounds are known at
489 -- compile time and if it requires at least as many bits as
490 -- a Positive to store the possible values.
491
492 return Compile_Time_Known_Value (Type_Low_Bound (T))
493 and then Compile_Time_Known_Value (Type_High_Bound (T))
494 and then
495 Minimum_Size (T, Biased => True) >=
496 RM_Size (Standard_Positive);
497 end Large_Storage_Type;
498
499 -- Start of processing for Check_Large
500
501 begin
502 -- Check that the Disc has a large range
503
504 if not Large_Storage_Type (Etype (Disc)) then
505 goto No_Danger;
506 end if;
507
508 -- If the enclosing type is limited, we allocate only the
509 -- default value, not the maximum, and there is no need for
510 -- a warning.
511
512 if Is_Limited_Type (Scope (Disc)) then
513 goto No_Danger;
514 end if;
515
516 -- Check that it is the high bound
517
518 if N /= High_Bound (PN)
519 or else No (Discriminant_Default_Value (Disc))
520 then
521 goto No_Danger;
522 end if;
523
524 -- Check the array allows a large range at this bound. First
525 -- find the array
526
527 SI := Parent (P);
528
529 if Nkind (SI) /= N_Subtype_Indication then
530 goto No_Danger;
531 end if;
532
533 T := Entity (Subtype_Mark (SI));
534
535 if not Is_Array_Type (T) then
536 goto No_Danger;
537 end if;
538
539 -- Next, find the dimension
540
541 TB := First_Index (T);
542 CB := First (Constraints (P));
543 while True
544 and then Present (TB)
545 and then Present (CB)
546 and then CB /= PN
547 loop
548 Next_Index (TB);
549 Next (CB);
550 end loop;
551
552 if CB /= PN then
553 goto No_Danger;
554 end if;
555
556 -- Now, check the dimension has a large range
557
558 if not Large_Storage_Type (Etype (TB)) then
559 goto No_Danger;
560 end if;
561
562 -- Warn about the danger
563
564 Error_Msg_N
565 ("??creation of & object may raise Storage_Error!",
566 Scope (Disc));
567
568 <<No_Danger>>
569 null;
570
571 end Check_Large;
572 end if;
573
574 -- Legal case is in index or discriminant constraint
575
576 elsif Nkind_In (PN, N_Index_Or_Discriminant_Constraint,
577 N_Discriminant_Association)
578 then
579 if Paren_Count (N) > 0 then
580 Error_Msg_N
581 ("discriminant in constraint must appear alone", N);
582
583 elsif Nkind (N) = N_Expanded_Name
584 and then Comes_From_Source (N)
585 then
586 Error_Msg_N
587 ("discriminant must appear alone as a direct name", N);
588 end if;
589
590 return;
591
592 -- Otherwise, context is an expression. It should not be within (i.e. a
593 -- subexpression of) a constraint for a component.
594
595 else
596 D := PN;
597 P := Parent (PN);
598 while not Nkind_In (P, N_Component_Declaration,
599 N_Subtype_Indication,
600 N_Entry_Declaration)
601 loop
602 D := P;
603 P := Parent (P);
604 exit when No (P);
605 end loop;
606
607 -- If the discriminant is used in an expression that is a bound of a
608 -- scalar type, an Itype is created and the bounds are attached to
609 -- its range, not to the original subtype indication. Such use is of
610 -- course a double fault.
611
612 if (Nkind (P) = N_Subtype_Indication
613 and then Nkind_In (Parent (P), N_Component_Definition,
614 N_Derived_Type_Definition)
615 and then D = Constraint (P))
616
617 -- The constraint itself may be given by a subtype indication,
618 -- rather than by a more common discrete range.
619
620 or else (Nkind (P) = N_Subtype_Indication
621 and then
622 Nkind (Parent (P)) = N_Index_Or_Discriminant_Constraint)
623 or else Nkind (P) = N_Entry_Declaration
624 or else Nkind (D) = N_Defining_Identifier
625 then
626 Error_Msg_N
627 ("discriminant in constraint must appear alone", N);
628 end if;
629 end if;
630 end Check_Discriminant_Use;
631
632 --------------------------------
633 -- Check_For_Visible_Operator --
634 --------------------------------
635
636 procedure Check_For_Visible_Operator (N : Node_Id; T : Entity_Id) is
637 begin
638 if Is_Invisible_Operator (N, T) then
639 Error_Msg_NE -- CODEFIX
640 ("operator for} is not directly visible!", N, First_Subtype (T));
641 Error_Msg_N -- CODEFIX
642 ("use clause would make operation legal!", N);
643 end if;
644 end Check_For_Visible_Operator;
645
646 ----------------------------------
647 -- Check_Fully_Declared_Prefix --
648 ----------------------------------
649
650 procedure Check_Fully_Declared_Prefix
651 (Typ : Entity_Id;
652 Pref : Node_Id)
653 is
654 begin
655 -- Check that the designated type of the prefix of a dereference is
656 -- not an incomplete type. This cannot be done unconditionally, because
657 -- dereferences of private types are legal in default expressions. This
658 -- case is taken care of in Check_Fully_Declared, called below. There
659 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
660
661 -- This consideration also applies to similar checks for allocators,
662 -- qualified expressions, and type conversions.
663
664 -- An additional exception concerns other per-object expressions that
665 -- are not directly related to component declarations, in particular
666 -- representation pragmas for tasks. These will be per-object
667 -- expressions if they depend on discriminants or some global entity.
668 -- If the task has access discriminants, the designated type may be
669 -- incomplete at the point the expression is resolved. This resolution
670 -- takes place within the body of the initialization procedure, where
671 -- the discriminant is replaced by its discriminal.
672
673 if Is_Entity_Name (Pref)
674 and then Ekind (Entity (Pref)) = E_In_Parameter
675 then
676 null;
677
678 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
679 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
680 -- Analyze_Object_Renaming, and Freeze_Entity.
681
682 elsif Ada_Version >= Ada_2005
683 and then Is_Entity_Name (Pref)
684 and then Is_Access_Type (Etype (Pref))
685 and then Ekind (Directly_Designated_Type (Etype (Pref))) =
686 E_Incomplete_Type
687 and then Is_Tagged_Type (Directly_Designated_Type (Etype (Pref)))
688 then
689 null;
690 else
691 Check_Fully_Declared (Typ, Parent (Pref));
692 end if;
693 end Check_Fully_Declared_Prefix;
694
695 ------------------------------
696 -- Check_Infinite_Recursion --
697 ------------------------------
698
699 function Check_Infinite_Recursion (N : Node_Id) return Boolean is
700 P : Node_Id;
701 C : Node_Id;
702
703 function Same_Argument_List return Boolean;
704 -- Check whether list of actuals is identical to list of formals of
705 -- called function (which is also the enclosing scope).
706
707 ------------------------
708 -- Same_Argument_List --
709 ------------------------
710
711 function Same_Argument_List return Boolean is
712 A : Node_Id;
713 F : Entity_Id;
714 Subp : Entity_Id;
715
716 begin
717 if not Is_Entity_Name (Name (N)) then
718 return False;
719 else
720 Subp := Entity (Name (N));
721 end if;
722
723 F := First_Formal (Subp);
724 A := First_Actual (N);
725 while Present (F) and then Present (A) loop
726 if not Is_Entity_Name (A) or else Entity (A) /= F then
727 return False;
728 end if;
729
730 Next_Actual (A);
731 Next_Formal (F);
732 end loop;
733
734 return True;
735 end Same_Argument_List;
736
737 -- Start of processing for Check_Infinite_Recursion
738
739 begin
740 -- Special case, if this is a procedure call and is a call to the
741 -- current procedure with the same argument list, then this is for
742 -- sure an infinite recursion and we insert a call to raise SE.
743
744 if Is_List_Member (N)
745 and then List_Length (List_Containing (N)) = 1
746 and then Same_Argument_List
747 then
748 declare
749 P : constant Node_Id := Parent (N);
750 begin
751 if Nkind (P) = N_Handled_Sequence_Of_Statements
752 and then Nkind (Parent (P)) = N_Subprogram_Body
753 and then Is_Empty_List (Declarations (Parent (P)))
754 then
755 Error_Msg_Warn := SPARK_Mode /= On;
756 Error_Msg_N ("!infinite recursion<<", N);
757 Error_Msg_N ("\!Storage_Error [<<", N);
758 Insert_Action (N,
759 Make_Raise_Storage_Error (Sloc (N),
760 Reason => SE_Infinite_Recursion));
761 return True;
762 end if;
763 end;
764 end if;
765
766 -- If not that special case, search up tree, quitting if we reach a
767 -- construct (e.g. a conditional) that tells us that this is not a
768 -- case for an infinite recursion warning.
769
770 C := N;
771 loop
772 P := Parent (C);
773
774 -- If no parent, then we were not inside a subprogram, this can for
775 -- example happen when processing certain pragmas in a spec. Just
776 -- return False in this case.
777
778 if No (P) then
779 return False;
780 end if;
781
782 -- Done if we get to subprogram body, this is definitely an infinite
783 -- recursion case if we did not find anything to stop us.
784
785 exit when Nkind (P) = N_Subprogram_Body;
786
787 -- If appearing in conditional, result is false
788
789 if Nkind_In (P, N_Or_Else,
790 N_And_Then,
791 N_Case_Expression,
792 N_Case_Statement,
793 N_If_Expression,
794 N_If_Statement)
795 then
796 return False;
797
798 elsif Nkind (P) = N_Handled_Sequence_Of_Statements
799 and then C /= First (Statements (P))
800 then
801 -- If the call is the expression of a return statement and the
802 -- actuals are identical to the formals, it's worth a warning.
803 -- However, we skip this if there is an immediately preceding
804 -- raise statement, since the call is never executed.
805
806 -- Furthermore, this corresponds to a common idiom:
807
808 -- function F (L : Thing) return Boolean is
809 -- begin
810 -- raise Program_Error;
811 -- return F (L);
812 -- end F;
813
814 -- for generating a stub function
815
816 if Nkind (Parent (N)) = N_Simple_Return_Statement
817 and then Same_Argument_List
818 then
819 exit when not Is_List_Member (Parent (N));
820
821 -- OK, return statement is in a statement list, look for raise
822
823 declare
824 Nod : Node_Id;
825
826 begin
827 -- Skip past N_Freeze_Entity nodes generated by expansion
828
829 Nod := Prev (Parent (N));
830 while Present (Nod)
831 and then Nkind (Nod) = N_Freeze_Entity
832 loop
833 Prev (Nod);
834 end loop;
835
836 -- If no raise statement, give warning. We look at the
837 -- original node, because in the case of "raise ... with
838 -- ...", the node has been transformed into a call.
839
840 exit when Nkind (Original_Node (Nod)) /= N_Raise_Statement
841 and then
842 (Nkind (Nod) not in N_Raise_xxx_Error
843 or else Present (Condition (Nod)));
844 end;
845 end if;
846
847 return False;
848
849 else
850 C := P;
851 end if;
852 end loop;
853
854 Error_Msg_Warn := SPARK_Mode /= On;
855 Error_Msg_N ("!possible infinite recursion<<", N);
856 Error_Msg_N ("\!??Storage_Error ]<<", N);
857
858 return True;
859 end Check_Infinite_Recursion;
860
861 -------------------------------
862 -- Check_Initialization_Call --
863 -------------------------------
864
865 procedure Check_Initialization_Call (N : Entity_Id; Nam : Entity_Id) is
866 Typ : constant Entity_Id := Etype (First_Formal (Nam));
867
868 function Uses_SS (T : Entity_Id) return Boolean;
869 -- Check whether the creation of an object of the type will involve
870 -- use of the secondary stack. If T is a record type, this is true
871 -- if the expression for some component uses the secondary stack, e.g.
872 -- through a call to a function that returns an unconstrained value.
873 -- False if T is controlled, because cleanups occur elsewhere.
874
875 -------------
876 -- Uses_SS --
877 -------------
878
879 function Uses_SS (T : Entity_Id) return Boolean is
880 Comp : Entity_Id;
881 Expr : Node_Id;
882 Full_Type : Entity_Id := Underlying_Type (T);
883
884 begin
885 -- Normally we want to use the underlying type, but if it's not set
886 -- then continue with T.
887
888 if not Present (Full_Type) then
889 Full_Type := T;
890 end if;
891
892 if Is_Controlled (Full_Type) then
893 return False;
894
895 elsif Is_Array_Type (Full_Type) then
896 return Uses_SS (Component_Type (Full_Type));
897
898 elsif Is_Record_Type (Full_Type) then
899 Comp := First_Component (Full_Type);
900 while Present (Comp) loop
901 if Ekind (Comp) = E_Component
902 and then Nkind (Parent (Comp)) = N_Component_Declaration
903 then
904 -- The expression for a dynamic component may be rewritten
905 -- as a dereference, so retrieve original node.
906
907 Expr := Original_Node (Expression (Parent (Comp)));
908
909 -- Return True if the expression is a call to a function
910 -- (including an attribute function such as Image, or a
911 -- user-defined operator) with a result that requires a
912 -- transient scope.
913
914 if (Nkind (Expr) = N_Function_Call
915 or else Nkind (Expr) in N_Op
916 or else (Nkind (Expr) = N_Attribute_Reference
917 and then Present (Expressions (Expr))))
918 and then Requires_Transient_Scope (Etype (Expr))
919 then
920 return True;
921
922 elsif Uses_SS (Etype (Comp)) then
923 return True;
924 end if;
925 end if;
926
927 Next_Component (Comp);
928 end loop;
929
930 return False;
931
932 else
933 return False;
934 end if;
935 end Uses_SS;
936
937 -- Start of processing for Check_Initialization_Call
938
939 begin
940 -- Establish a transient scope if the type needs it
941
942 if Uses_SS (Typ) then
943 Establish_Transient_Scope (First_Actual (N), Sec_Stack => True);
944 end if;
945 end Check_Initialization_Call;
946
947 ---------------------------------------
948 -- Check_No_Direct_Boolean_Operators --
949 ---------------------------------------
950
951 procedure Check_No_Direct_Boolean_Operators (N : Node_Id) is
952 begin
953 if Scope (Entity (N)) = Standard_Standard
954 and then Root_Type (Etype (Left_Opnd (N))) = Standard_Boolean
955 then
956 -- Restriction only applies to original source code
957
958 if Comes_From_Source (N) then
959 Check_Restriction (No_Direct_Boolean_Operators, N);
960 end if;
961 end if;
962
963 -- Do style check (but skip if in instance, error is on template)
964
965 if Style_Check then
966 if not In_Instance then
967 Check_Boolean_Operator (N);
968 end if;
969 end if;
970 end Check_No_Direct_Boolean_Operators;
971
972 ------------------------------
973 -- Check_Parameterless_Call --
974 ------------------------------
975
976 procedure Check_Parameterless_Call (N : Node_Id) is
977 Nam : Node_Id;
978
979 function Prefix_Is_Access_Subp return Boolean;
980 -- If the prefix is of an access_to_subprogram type, the node must be
981 -- rewritten as a call. Ditto if the prefix is overloaded and all its
982 -- interpretations are access to subprograms.
983
984 ---------------------------
985 -- Prefix_Is_Access_Subp --
986 ---------------------------
987
988 function Prefix_Is_Access_Subp return Boolean is
989 I : Interp_Index;
990 It : Interp;
991
992 begin
993 -- If the context is an attribute reference that can apply to
994 -- functions, this is never a parameterless call (RM 4.1.4(6)).
995
996 if Nkind (Parent (N)) = N_Attribute_Reference
997 and then Nam_In (Attribute_Name (Parent (N)), Name_Address,
998 Name_Code_Address,
999 Name_Access)
1000 then
1001 return False;
1002 end if;
1003
1004 if not Is_Overloaded (N) then
1005 return
1006 Ekind (Etype (N)) = E_Subprogram_Type
1007 and then Base_Type (Etype (Etype (N))) /= Standard_Void_Type;
1008 else
1009 Get_First_Interp (N, I, It);
1010 while Present (It.Typ) loop
1011 if Ekind (It.Typ) /= E_Subprogram_Type
1012 or else Base_Type (Etype (It.Typ)) = Standard_Void_Type
1013 then
1014 return False;
1015 end if;
1016
1017 Get_Next_Interp (I, It);
1018 end loop;
1019
1020 return True;
1021 end if;
1022 end Prefix_Is_Access_Subp;
1023
1024 -- Start of processing for Check_Parameterless_Call
1025
1026 begin
1027 -- Defend against junk stuff if errors already detected
1028
1029 if Total_Errors_Detected /= 0 then
1030 if Nkind (N) in N_Has_Etype and then Etype (N) = Any_Type then
1031 return;
1032 elsif Nkind (N) in N_Has_Chars
1033 and then Chars (N) in Error_Name_Or_No_Name
1034 then
1035 return;
1036 end if;
1037
1038 Require_Entity (N);
1039 end if;
1040
1041 -- If the context expects a value, and the name is a procedure, this is
1042 -- most likely a missing 'Access. Don't try to resolve the parameterless
1043 -- call, error will be caught when the outer call is analyzed.
1044
1045 if Is_Entity_Name (N)
1046 and then Ekind (Entity (N)) = E_Procedure
1047 and then not Is_Overloaded (N)
1048 and then
1049 Nkind_In (Parent (N), N_Parameter_Association,
1050 N_Function_Call,
1051 N_Procedure_Call_Statement)
1052 then
1053 return;
1054 end if;
1055
1056 -- Rewrite as call if overloadable entity that is (or could be, in the
1057 -- overloaded case) a function call. If we know for sure that the entity
1058 -- is an enumeration literal, we do not rewrite it.
1059
1060 -- If the entity is the name of an operator, it cannot be a call because
1061 -- operators cannot have default parameters. In this case, this must be
1062 -- a string whose contents coincide with an operator name. Set the kind
1063 -- of the node appropriately.
1064
1065 if (Is_Entity_Name (N)
1066 and then Nkind (N) /= N_Operator_Symbol
1067 and then Is_Overloadable (Entity (N))
1068 and then (Ekind (Entity (N)) /= E_Enumeration_Literal
1069 or else Is_Overloaded (N)))
1070
1071 -- Rewrite as call if it is an explicit dereference of an expression of
1072 -- a subprogram access type, and the subprogram type is not that of a
1073 -- procedure or entry.
1074
1075 or else
1076 (Nkind (N) = N_Explicit_Dereference and then Prefix_Is_Access_Subp)
1077
1078 -- Rewrite as call if it is a selected component which is a function,
1079 -- this is the case of a call to a protected function (which may be
1080 -- overloaded with other protected operations).
1081
1082 or else
1083 (Nkind (N) = N_Selected_Component
1084 and then (Ekind (Entity (Selector_Name (N))) = E_Function
1085 or else
1086 (Ekind_In (Entity (Selector_Name (N)), E_Entry,
1087 E_Procedure)
1088 and then Is_Overloaded (Selector_Name (N)))))
1089
1090 -- If one of the above three conditions is met, rewrite as call. Apply
1091 -- the rewriting only once.
1092
1093 then
1094 if Nkind (Parent (N)) /= N_Function_Call
1095 or else N /= Name (Parent (N))
1096 then
1097
1098 -- This may be a prefixed call that was not fully analyzed, e.g.
1099 -- an actual in an instance.
1100
1101 if Ada_Version >= Ada_2005
1102 and then Nkind (N) = N_Selected_Component
1103 and then Is_Dispatching_Operation (Entity (Selector_Name (N)))
1104 then
1105 Analyze_Selected_Component (N);
1106
1107 if Nkind (N) /= N_Selected_Component then
1108 return;
1109 end if;
1110 end if;
1111
1112 -- The node is the name of the parameterless call. Preserve its
1113 -- descendants, which may be complex expressions.
1114
1115 Nam := Relocate_Node (N);
1116
1117 -- If overloaded, overload set belongs to new copy
1118
1119 Save_Interps (N, Nam);
1120
1121 -- Change node to parameterless function call (note that the
1122 -- Parameter_Associations associations field is left set to Empty,
1123 -- its normal default value since there are no parameters)
1124
1125 Change_Node (N, N_Function_Call);
1126 Set_Name (N, Nam);
1127 Set_Sloc (N, Sloc (Nam));
1128 Analyze_Call (N);
1129 end if;
1130
1131 elsif Nkind (N) = N_Parameter_Association then
1132 Check_Parameterless_Call (Explicit_Actual_Parameter (N));
1133
1134 elsif Nkind (N) = N_Operator_Symbol then
1135 Change_Operator_Symbol_To_String_Literal (N);
1136 Set_Is_Overloaded (N, False);
1137 Set_Etype (N, Any_String);
1138 end if;
1139 end Check_Parameterless_Call;
1140
1141 --------------------------------
1142 -- Is_Atomic_Ref_With_Address --
1143 --------------------------------
1144
1145 function Is_Atomic_Ref_With_Address (N : Node_Id) return Boolean is
1146 Pref : constant Node_Id := Prefix (N);
1147
1148 begin
1149 if not Is_Entity_Name (Pref) then
1150 return False;
1151
1152 else
1153 declare
1154 Pent : constant Entity_Id := Entity (Pref);
1155 Ptyp : constant Entity_Id := Etype (Pent);
1156 begin
1157 return not Is_Access_Type (Ptyp)
1158 and then (Is_Atomic (Ptyp) or else Is_Atomic (Pent))
1159 and then Present (Address_Clause (Pent));
1160 end;
1161 end if;
1162 end Is_Atomic_Ref_With_Address;
1163
1164 -----------------------------
1165 -- Is_Definite_Access_Type --
1166 -----------------------------
1167
1168 function Is_Definite_Access_Type (E : Entity_Id) return Boolean is
1169 Btyp : constant Entity_Id := Base_Type (E);
1170 begin
1171 return Ekind (Btyp) = E_Access_Type
1172 or else (Ekind (Btyp) = E_Access_Subprogram_Type
1173 and then Comes_From_Source (Btyp));
1174 end Is_Definite_Access_Type;
1175
1176 ----------------------
1177 -- Is_Predefined_Op --
1178 ----------------------
1179
1180 function Is_Predefined_Op (Nam : Entity_Id) return Boolean is
1181 begin
1182 -- Predefined operators are intrinsic subprograms
1183
1184 if not Is_Intrinsic_Subprogram (Nam) then
1185 return False;
1186 end if;
1187
1188 -- A call to a back-end builtin is never a predefined operator
1189
1190 if Is_Imported (Nam) and then Present (Interface_Name (Nam)) then
1191 return False;
1192 end if;
1193
1194 return not Is_Generic_Instance (Nam)
1195 and then Chars (Nam) in Any_Operator_Name
1196 and then (No (Alias (Nam)) or else Is_Predefined_Op (Alias (Nam)));
1197 end Is_Predefined_Op;
1198
1199 -----------------------------
1200 -- Make_Call_Into_Operator --
1201 -----------------------------
1202
1203 procedure Make_Call_Into_Operator
1204 (N : Node_Id;
1205 Typ : Entity_Id;
1206 Op_Id : Entity_Id)
1207 is
1208 Op_Name : constant Name_Id := Chars (Op_Id);
1209 Act1 : Node_Id := First_Actual (N);
1210 Act2 : Node_Id := Next_Actual (Act1);
1211 Error : Boolean := False;
1212 Func : constant Entity_Id := Entity (Name (N));
1213 Is_Binary : constant Boolean := Present (Act2);
1214 Op_Node : Node_Id;
1215 Opnd_Type : Entity_Id;
1216 Orig_Type : Entity_Id := Empty;
1217 Pack : Entity_Id;
1218
1219 type Kind_Test is access function (E : Entity_Id) return Boolean;
1220
1221 function Operand_Type_In_Scope (S : Entity_Id) return Boolean;
1222 -- If the operand is not universal, and the operator is given by an
1223 -- expanded name, verify that the operand has an interpretation with a
1224 -- type defined in the given scope of the operator.
1225
1226 function Type_In_P (Test : Kind_Test) return Entity_Id;
1227 -- Find a type of the given class in package Pack that contains the
1228 -- operator.
1229
1230 ---------------------------
1231 -- Operand_Type_In_Scope --
1232 ---------------------------
1233
1234 function Operand_Type_In_Scope (S : Entity_Id) return Boolean is
1235 Nod : constant Node_Id := Right_Opnd (Op_Node);
1236 I : Interp_Index;
1237 It : Interp;
1238
1239 begin
1240 if not Is_Overloaded (Nod) then
1241 return Scope (Base_Type (Etype (Nod))) = S;
1242
1243 else
1244 Get_First_Interp (Nod, I, It);
1245 while Present (It.Typ) loop
1246 if Scope (Base_Type (It.Typ)) = S then
1247 return True;
1248 end if;
1249
1250 Get_Next_Interp (I, It);
1251 end loop;
1252
1253 return False;
1254 end if;
1255 end Operand_Type_In_Scope;
1256
1257 ---------------
1258 -- Type_In_P --
1259 ---------------
1260
1261 function Type_In_P (Test : Kind_Test) return Entity_Id is
1262 E : Entity_Id;
1263
1264 function In_Decl return Boolean;
1265 -- Verify that node is not part of the type declaration for the
1266 -- candidate type, which would otherwise be invisible.
1267
1268 -------------
1269 -- In_Decl --
1270 -------------
1271
1272 function In_Decl return Boolean is
1273 Decl_Node : constant Node_Id := Parent (E);
1274 N2 : Node_Id;
1275
1276 begin
1277 N2 := N;
1278
1279 if Etype (E) = Any_Type then
1280 return True;
1281
1282 elsif No (Decl_Node) then
1283 return False;
1284
1285 else
1286 while Present (N2)
1287 and then Nkind (N2) /= N_Compilation_Unit
1288 loop
1289 if N2 = Decl_Node then
1290 return True;
1291 else
1292 N2 := Parent (N2);
1293 end if;
1294 end loop;
1295
1296 return False;
1297 end if;
1298 end In_Decl;
1299
1300 -- Start of processing for Type_In_P
1301
1302 begin
1303 -- If the context type is declared in the prefix package, this is the
1304 -- desired base type.
1305
1306 if Scope (Base_Type (Typ)) = Pack and then Test (Typ) then
1307 return Base_Type (Typ);
1308
1309 else
1310 E := First_Entity (Pack);
1311 while Present (E) loop
1312 if Test (E) and then not In_Decl then
1313 return E;
1314 end if;
1315
1316 Next_Entity (E);
1317 end loop;
1318
1319 return Empty;
1320 end if;
1321 end Type_In_P;
1322
1323 -- Start of processing for Make_Call_Into_Operator
1324
1325 begin
1326 Op_Node := New_Node (Operator_Kind (Op_Name, Is_Binary), Sloc (N));
1327
1328 -- Binary operator
1329
1330 if Is_Binary then
1331 Set_Left_Opnd (Op_Node, Relocate_Node (Act1));
1332 Set_Right_Opnd (Op_Node, Relocate_Node (Act2));
1333 Save_Interps (Act1, Left_Opnd (Op_Node));
1334 Save_Interps (Act2, Right_Opnd (Op_Node));
1335 Act1 := Left_Opnd (Op_Node);
1336 Act2 := Right_Opnd (Op_Node);
1337
1338 -- Unary operator
1339
1340 else
1341 Set_Right_Opnd (Op_Node, Relocate_Node (Act1));
1342 Save_Interps (Act1, Right_Opnd (Op_Node));
1343 Act1 := Right_Opnd (Op_Node);
1344 end if;
1345
1346 -- If the operator is denoted by an expanded name, and the prefix is
1347 -- not Standard, but the operator is a predefined one whose scope is
1348 -- Standard, then this is an implicit_operator, inserted as an
1349 -- interpretation by the procedure of the same name. This procedure
1350 -- overestimates the presence of implicit operators, because it does
1351 -- not examine the type of the operands. Verify now that the operand
1352 -- type appears in the given scope. If right operand is universal,
1353 -- check the other operand. In the case of concatenation, either
1354 -- argument can be the component type, so check the type of the result.
1355 -- If both arguments are literals, look for a type of the right kind
1356 -- defined in the given scope. This elaborate nonsense is brought to
1357 -- you courtesy of b33302a. The type itself must be frozen, so we must
1358 -- find the type of the proper class in the given scope.
1359
1360 -- A final wrinkle is the multiplication operator for fixed point types,
1361 -- which is defined in Standard only, and not in the scope of the
1362 -- fixed point type itself.
1363
1364 if Nkind (Name (N)) = N_Expanded_Name then
1365 Pack := Entity (Prefix (Name (N)));
1366
1367 -- If this is a package renaming, get renamed entity, which will be
1368 -- the scope of the operands if operaton is type-correct.
1369
1370 if Present (Renamed_Entity (Pack)) then
1371 Pack := Renamed_Entity (Pack);
1372 end if;
1373
1374 -- If the entity being called is defined in the given package, it is
1375 -- a renaming of a predefined operator, and known to be legal.
1376
1377 if Scope (Entity (Name (N))) = Pack
1378 and then Pack /= Standard_Standard
1379 then
1380 null;
1381
1382 -- Visibility does not need to be checked in an instance: if the
1383 -- operator was not visible in the generic it has been diagnosed
1384 -- already, else there is an implicit copy of it in the instance.
1385
1386 elsif In_Instance then
1387 null;
1388
1389 elsif Nam_In (Op_Name, Name_Op_Multiply, Name_Op_Divide)
1390 and then Is_Fixed_Point_Type (Etype (Left_Opnd (Op_Node)))
1391 and then Is_Fixed_Point_Type (Etype (Right_Opnd (Op_Node)))
1392 then
1393 if Pack /= Standard_Standard then
1394 Error := True;
1395 end if;
1396
1397 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1398 -- available.
1399
1400 elsif Ada_Version >= Ada_2005
1401 and then Nam_In (Op_Name, Name_Op_Eq, Name_Op_Ne)
1402 and then Ekind (Etype (Act1)) = E_Anonymous_Access_Type
1403 then
1404 null;
1405
1406 else
1407 Opnd_Type := Base_Type (Etype (Right_Opnd (Op_Node)));
1408
1409 if Op_Name = Name_Op_Concat then
1410 Opnd_Type := Base_Type (Typ);
1411
1412 elsif (Scope (Opnd_Type) = Standard_Standard
1413 and then Is_Binary)
1414 or else (Nkind (Right_Opnd (Op_Node)) = N_Attribute_Reference
1415 and then Is_Binary
1416 and then not Comes_From_Source (Opnd_Type))
1417 then
1418 Opnd_Type := Base_Type (Etype (Left_Opnd (Op_Node)));
1419 end if;
1420
1421 if Scope (Opnd_Type) = Standard_Standard then
1422
1423 -- Verify that the scope contains a type that corresponds to
1424 -- the given literal. Optimize the case where Pack is Standard.
1425
1426 if Pack /= Standard_Standard then
1427
1428 if Opnd_Type = Universal_Integer then
1429 Orig_Type := Type_In_P (Is_Integer_Type'Access);
1430
1431 elsif Opnd_Type = Universal_Real then
1432 Orig_Type := Type_In_P (Is_Real_Type'Access);
1433
1434 elsif Opnd_Type = Any_String then
1435 Orig_Type := Type_In_P (Is_String_Type'Access);
1436
1437 elsif Opnd_Type = Any_Access then
1438 Orig_Type := Type_In_P (Is_Definite_Access_Type'Access);
1439
1440 elsif Opnd_Type = Any_Composite then
1441 Orig_Type := Type_In_P (Is_Composite_Type'Access);
1442
1443 if Present (Orig_Type) then
1444 if Has_Private_Component (Orig_Type) then
1445 Orig_Type := Empty;
1446 else
1447 Set_Etype (Act1, Orig_Type);
1448
1449 if Is_Binary then
1450 Set_Etype (Act2, Orig_Type);
1451 end if;
1452 end if;
1453 end if;
1454
1455 else
1456 Orig_Type := Empty;
1457 end if;
1458
1459 Error := No (Orig_Type);
1460 end if;
1461
1462 elsif Ekind (Opnd_Type) = E_Allocator_Type
1463 and then No (Type_In_P (Is_Definite_Access_Type'Access))
1464 then
1465 Error := True;
1466
1467 -- If the type is defined elsewhere, and the operator is not
1468 -- defined in the given scope (by a renaming declaration, e.g.)
1469 -- then this is an error as well. If an extension of System is
1470 -- present, and the type may be defined there, Pack must be
1471 -- System itself.
1472
1473 elsif Scope (Opnd_Type) /= Pack
1474 and then Scope (Op_Id) /= Pack
1475 and then (No (System_Aux_Id)
1476 or else Scope (Opnd_Type) /= System_Aux_Id
1477 or else Pack /= Scope (System_Aux_Id))
1478 then
1479 if not Is_Overloaded (Right_Opnd (Op_Node)) then
1480 Error := True;
1481 else
1482 Error := not Operand_Type_In_Scope (Pack);
1483 end if;
1484
1485 elsif Pack = Standard_Standard
1486 and then not Operand_Type_In_Scope (Standard_Standard)
1487 then
1488 Error := True;
1489 end if;
1490 end if;
1491
1492 if Error then
1493 Error_Msg_Node_2 := Pack;
1494 Error_Msg_NE
1495 ("& not declared in&", N, Selector_Name (Name (N)));
1496 Set_Etype (N, Any_Type);
1497 return;
1498
1499 -- Detect a mismatch between the context type and the result type
1500 -- in the named package, which is otherwise not detected if the
1501 -- operands are universal. Check is only needed if source entity is
1502 -- an operator, not a function that renames an operator.
1503
1504 elsif Nkind (Parent (N)) /= N_Type_Conversion
1505 and then Ekind (Entity (Name (N))) = E_Operator
1506 and then Is_Numeric_Type (Typ)
1507 and then not Is_Universal_Numeric_Type (Typ)
1508 and then Scope (Base_Type (Typ)) /= Pack
1509 and then not In_Instance
1510 then
1511 if Is_Fixed_Point_Type (Typ)
1512 and then Nam_In (Op_Name, Name_Op_Multiply, Name_Op_Divide)
1513 then
1514 -- Already checked above
1515
1516 null;
1517
1518 -- Operator may be defined in an extension of System
1519
1520 elsif Present (System_Aux_Id)
1521 and then Scope (Opnd_Type) = System_Aux_Id
1522 then
1523 null;
1524
1525 else
1526 -- Could we use Wrong_Type here??? (this would require setting
1527 -- Etype (N) to the actual type found where Typ was expected).
1528
1529 Error_Msg_NE ("expect }", N, Typ);
1530 end if;
1531 end if;
1532 end if;
1533
1534 Set_Chars (Op_Node, Op_Name);
1535
1536 if not Is_Private_Type (Etype (N)) then
1537 Set_Etype (Op_Node, Base_Type (Etype (N)));
1538 else
1539 Set_Etype (Op_Node, Etype (N));
1540 end if;
1541
1542 -- If this is a call to a function that renames a predefined equality,
1543 -- the renaming declaration provides a type that must be used to
1544 -- resolve the operands. This must be done now because resolution of
1545 -- the equality node will not resolve any remaining ambiguity, and it
1546 -- assumes that the first operand is not overloaded.
1547
1548 if Nam_In (Op_Name, Name_Op_Eq, Name_Op_Ne)
1549 and then Ekind (Func) = E_Function
1550 and then Is_Overloaded (Act1)
1551 then
1552 Resolve (Act1, Base_Type (Etype (First_Formal (Func))));
1553 Resolve (Act2, Base_Type (Etype (First_Formal (Func))));
1554 end if;
1555
1556 Set_Entity (Op_Node, Op_Id);
1557 Generate_Reference (Op_Id, N, ' ');
1558
1559 -- Do rewrite setting Comes_From_Source on the result if the original
1560 -- call came from source. Although it is not strictly the case that the
1561 -- operator as such comes from the source, logically it corresponds
1562 -- exactly to the function call in the source, so it should be marked
1563 -- this way (e.g. to make sure that validity checks work fine).
1564
1565 declare
1566 CS : constant Boolean := Comes_From_Source (N);
1567 begin
1568 Rewrite (N, Op_Node);
1569 Set_Comes_From_Source (N, CS);
1570 end;
1571
1572 -- If this is an arithmetic operator and the result type is private,
1573 -- the operands and the result must be wrapped in conversion to
1574 -- expose the underlying numeric type and expand the proper checks,
1575 -- e.g. on division.
1576
1577 if Is_Private_Type (Typ) then
1578 case Nkind (N) is
1579 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1580 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1581 Resolve_Intrinsic_Operator (N, Typ);
1582
1583 when N_Op_Plus | N_Op_Minus | N_Op_Abs =>
1584 Resolve_Intrinsic_Unary_Operator (N, Typ);
1585
1586 when others =>
1587 Resolve (N, Typ);
1588 end case;
1589 else
1590 Resolve (N, Typ);
1591 end if;
1592
1593 -- If in ASIS_Mode, propagate operand types to original actuals of
1594 -- function call, which would otherwise not be fully resolved. If
1595 -- the call has already been constant-folded, nothing to do. We
1596 -- relocate the operand nodes rather than copy them, to preserve
1597 -- original_node pointers, given that the operands themselves may
1598 -- have been rewritten. If the call was itself a rewriting of an
1599 -- operator node, nothing to do.
1600
1601 if ASIS_Mode
1602 and then Nkind (N) in N_Op
1603 and then Nkind (Original_Node (N)) = N_Function_Call
1604 then
1605 declare
1606 L : Node_Id;
1607 R : constant Node_Id := Right_Opnd (N);
1608
1609 Old_First : constant Node_Id :=
1610 First (Parameter_Associations (Original_Node (N)));
1611 Old_Sec : Node_Id;
1612
1613 begin
1614 if Is_Binary then
1615 L := Left_Opnd (N);
1616 Old_Sec := Next (Old_First);
1617
1618 -- If the original call has named associations, replace the
1619 -- explicit actual parameter in the association with the proper
1620 -- resolved operand.
1621
1622 if Nkind (Old_First) = N_Parameter_Association then
1623 if Chars (Selector_Name (Old_First)) =
1624 Chars (First_Entity (Op_Id))
1625 then
1626 Rewrite (Explicit_Actual_Parameter (Old_First),
1627 Relocate_Node (L));
1628 else
1629 Rewrite (Explicit_Actual_Parameter (Old_First),
1630 Relocate_Node (R));
1631 end if;
1632
1633 else
1634 Rewrite (Old_First, Relocate_Node (L));
1635 end if;
1636
1637 if Nkind (Old_Sec) = N_Parameter_Association then
1638 if Chars (Selector_Name (Old_Sec)) =
1639 Chars (First_Entity (Op_Id))
1640 then
1641 Rewrite (Explicit_Actual_Parameter (Old_Sec),
1642 Relocate_Node (L));
1643 else
1644 Rewrite (Explicit_Actual_Parameter (Old_Sec),
1645 Relocate_Node (R));
1646 end if;
1647
1648 else
1649 Rewrite (Old_Sec, Relocate_Node (R));
1650 end if;
1651
1652 else
1653 if Nkind (Old_First) = N_Parameter_Association then
1654 Rewrite (Explicit_Actual_Parameter (Old_First),
1655 Relocate_Node (R));
1656 else
1657 Rewrite (Old_First, Relocate_Node (R));
1658 end if;
1659 end if;
1660 end;
1661
1662 Set_Parent (Original_Node (N), Parent (N));
1663 end if;
1664 end Make_Call_Into_Operator;
1665
1666 -------------------
1667 -- Operator_Kind --
1668 -------------------
1669
1670 function Operator_Kind
1671 (Op_Name : Name_Id;
1672 Is_Binary : Boolean) return Node_Kind
1673 is
1674 Kind : Node_Kind;
1675
1676 begin
1677 -- Use CASE statement or array???
1678
1679 if Is_Binary then
1680 if Op_Name = Name_Op_And then
1681 Kind := N_Op_And;
1682 elsif Op_Name = Name_Op_Or then
1683 Kind := N_Op_Or;
1684 elsif Op_Name = Name_Op_Xor then
1685 Kind := N_Op_Xor;
1686 elsif Op_Name = Name_Op_Eq then
1687 Kind := N_Op_Eq;
1688 elsif Op_Name = Name_Op_Ne then
1689 Kind := N_Op_Ne;
1690 elsif Op_Name = Name_Op_Lt then
1691 Kind := N_Op_Lt;
1692 elsif Op_Name = Name_Op_Le then
1693 Kind := N_Op_Le;
1694 elsif Op_Name = Name_Op_Gt then
1695 Kind := N_Op_Gt;
1696 elsif Op_Name = Name_Op_Ge then
1697 Kind := N_Op_Ge;
1698 elsif Op_Name = Name_Op_Add then
1699 Kind := N_Op_Add;
1700 elsif Op_Name = Name_Op_Subtract then
1701 Kind := N_Op_Subtract;
1702 elsif Op_Name = Name_Op_Concat then
1703 Kind := N_Op_Concat;
1704 elsif Op_Name = Name_Op_Multiply then
1705 Kind := N_Op_Multiply;
1706 elsif Op_Name = Name_Op_Divide then
1707 Kind := N_Op_Divide;
1708 elsif Op_Name = Name_Op_Mod then
1709 Kind := N_Op_Mod;
1710 elsif Op_Name = Name_Op_Rem then
1711 Kind := N_Op_Rem;
1712 elsif Op_Name = Name_Op_Expon then
1713 Kind := N_Op_Expon;
1714 else
1715 raise Program_Error;
1716 end if;
1717
1718 -- Unary operators
1719
1720 else
1721 if Op_Name = Name_Op_Add then
1722 Kind := N_Op_Plus;
1723 elsif Op_Name = Name_Op_Subtract then
1724 Kind := N_Op_Minus;
1725 elsif Op_Name = Name_Op_Abs then
1726 Kind := N_Op_Abs;
1727 elsif Op_Name = Name_Op_Not then
1728 Kind := N_Op_Not;
1729 else
1730 raise Program_Error;
1731 end if;
1732 end if;
1733
1734 return Kind;
1735 end Operator_Kind;
1736
1737 ----------------------------
1738 -- Preanalyze_And_Resolve --
1739 ----------------------------
1740
1741 procedure Preanalyze_And_Resolve (N : Node_Id; T : Entity_Id) is
1742 Save_Full_Analysis : constant Boolean := Full_Analysis;
1743
1744 begin
1745 Full_Analysis := False;
1746 Expander_Mode_Save_And_Set (False);
1747
1748 -- Normally, we suppress all checks for this preanalysis. There is no
1749 -- point in processing them now, since they will be applied properly
1750 -- and in the proper location when the default expressions reanalyzed
1751 -- and reexpanded later on. We will also have more information at that
1752 -- point for possible suppression of individual checks.
1753
1754 -- However, in SPARK mode, most expansion is suppressed, and this
1755 -- later reanalysis and reexpansion may not occur. SPARK mode does
1756 -- require the setting of checking flags for proof purposes, so we
1757 -- do the SPARK preanalysis without suppressing checks.
1758
1759 -- This special handling for SPARK mode is required for example in the
1760 -- case of Ada 2012 constructs such as quantified expressions, which are
1761 -- expanded in two separate steps.
1762
1763 if GNATprove_Mode then
1764 Analyze_And_Resolve (N, T);
1765 else
1766 Analyze_And_Resolve (N, T, Suppress => All_Checks);
1767 end if;
1768
1769 Expander_Mode_Restore;
1770 Full_Analysis := Save_Full_Analysis;
1771 end Preanalyze_And_Resolve;
1772
1773 -- Version without context type
1774
1775 procedure Preanalyze_And_Resolve (N : Node_Id) is
1776 Save_Full_Analysis : constant Boolean := Full_Analysis;
1777
1778 begin
1779 Full_Analysis := False;
1780 Expander_Mode_Save_And_Set (False);
1781
1782 Analyze (N);
1783 Resolve (N, Etype (N), Suppress => All_Checks);
1784
1785 Expander_Mode_Restore;
1786 Full_Analysis := Save_Full_Analysis;
1787 end Preanalyze_And_Resolve;
1788
1789 ----------------------------------
1790 -- Replace_Actual_Discriminants --
1791 ----------------------------------
1792
1793 procedure Replace_Actual_Discriminants (N : Node_Id; Default : Node_Id) is
1794 Loc : constant Source_Ptr := Sloc (N);
1795 Tsk : Node_Id := Empty;
1796
1797 function Process_Discr (Nod : Node_Id) return Traverse_Result;
1798 -- Comment needed???
1799
1800 -------------------
1801 -- Process_Discr --
1802 -------------------
1803
1804 function Process_Discr (Nod : Node_Id) return Traverse_Result is
1805 Ent : Entity_Id;
1806
1807 begin
1808 if Nkind (Nod) = N_Identifier then
1809 Ent := Entity (Nod);
1810
1811 if Present (Ent)
1812 and then Ekind (Ent) = E_Discriminant
1813 then
1814 Rewrite (Nod,
1815 Make_Selected_Component (Loc,
1816 Prefix => New_Copy_Tree (Tsk, New_Sloc => Loc),
1817 Selector_Name => Make_Identifier (Loc, Chars (Ent))));
1818
1819 Set_Etype (Nod, Etype (Ent));
1820 end if;
1821
1822 end if;
1823
1824 return OK;
1825 end Process_Discr;
1826
1827 procedure Replace_Discrs is new Traverse_Proc (Process_Discr);
1828
1829 -- Start of processing for Replace_Actual_Discriminants
1830
1831 begin
1832 if not Expander_Active then
1833 return;
1834 end if;
1835
1836 if Nkind (Name (N)) = N_Selected_Component then
1837 Tsk := Prefix (Name (N));
1838
1839 elsif Nkind (Name (N)) = N_Indexed_Component then
1840 Tsk := Prefix (Prefix (Name (N)));
1841 end if;
1842
1843 if No (Tsk) then
1844 return;
1845 else
1846 Replace_Discrs (Default);
1847 end if;
1848 end Replace_Actual_Discriminants;
1849
1850 -------------
1851 -- Resolve --
1852 -------------
1853
1854 procedure Resolve (N : Node_Id; Typ : Entity_Id) is
1855 Ambiguous : Boolean := False;
1856 Ctx_Type : Entity_Id := Typ;
1857 Expr_Type : Entity_Id := Empty; -- prevent junk warning
1858 Err_Type : Entity_Id := Empty;
1859 Found : Boolean := False;
1860 From_Lib : Boolean;
1861 I : Interp_Index;
1862 I1 : Interp_Index := 0; -- prevent junk warning
1863 It : Interp;
1864 It1 : Interp;
1865 Seen : Entity_Id := Empty; -- prevent junk warning
1866
1867 function Comes_From_Predefined_Lib_Unit (Nod : Node_Id) return Boolean;
1868 -- Determine whether a node comes from a predefined library unit or
1869 -- Standard.
1870
1871 procedure Patch_Up_Value (N : Node_Id; Typ : Entity_Id);
1872 -- Try and fix up a literal so that it matches its expected type. New
1873 -- literals are manufactured if necessary to avoid cascaded errors.
1874
1875 procedure Report_Ambiguous_Argument;
1876 -- Additional diagnostics when an ambiguous call has an ambiguous
1877 -- argument (typically a controlling actual).
1878
1879 procedure Resolution_Failed;
1880 -- Called when attempt at resolving current expression fails
1881
1882 ------------------------------------
1883 -- Comes_From_Predefined_Lib_Unit --
1884 -------------------------------------
1885
1886 function Comes_From_Predefined_Lib_Unit (Nod : Node_Id) return Boolean is
1887 begin
1888 return
1889 Sloc (Nod) = Standard_Location
1890 or else Is_Predefined_File_Name
1891 (Unit_File_Name (Get_Source_Unit (Sloc (Nod))));
1892 end Comes_From_Predefined_Lib_Unit;
1893
1894 --------------------
1895 -- Patch_Up_Value --
1896 --------------------
1897
1898 procedure Patch_Up_Value (N : Node_Id; Typ : Entity_Id) is
1899 begin
1900 if Nkind (N) = N_Integer_Literal and then Is_Real_Type (Typ) then
1901 Rewrite (N,
1902 Make_Real_Literal (Sloc (N),
1903 Realval => UR_From_Uint (Intval (N))));
1904 Set_Etype (N, Universal_Real);
1905 Set_Is_Static_Expression (N);
1906
1907 elsif Nkind (N) = N_Real_Literal and then Is_Integer_Type (Typ) then
1908 Rewrite (N,
1909 Make_Integer_Literal (Sloc (N),
1910 Intval => UR_To_Uint (Realval (N))));
1911 Set_Etype (N, Universal_Integer);
1912 Set_Is_Static_Expression (N);
1913
1914 elsif Nkind (N) = N_String_Literal
1915 and then Is_Character_Type (Typ)
1916 then
1917 Set_Character_Literal_Name (Char_Code (Character'Pos ('A')));
1918 Rewrite (N,
1919 Make_Character_Literal (Sloc (N),
1920 Chars => Name_Find,
1921 Char_Literal_Value =>
1922 UI_From_Int (Character'Pos ('A'))));
1923 Set_Etype (N, Any_Character);
1924 Set_Is_Static_Expression (N);
1925
1926 elsif Nkind (N) /= N_String_Literal and then Is_String_Type (Typ) then
1927 Rewrite (N,
1928 Make_String_Literal (Sloc (N),
1929 Strval => End_String));
1930
1931 elsif Nkind (N) = N_Range then
1932 Patch_Up_Value (Low_Bound (N), Typ);
1933 Patch_Up_Value (High_Bound (N), Typ);
1934 end if;
1935 end Patch_Up_Value;
1936
1937 -------------------------------
1938 -- Report_Ambiguous_Argument --
1939 -------------------------------
1940
1941 procedure Report_Ambiguous_Argument is
1942 Arg : constant Node_Id := First (Parameter_Associations (N));
1943 I : Interp_Index;
1944 It : Interp;
1945
1946 begin
1947 if Nkind (Arg) = N_Function_Call
1948 and then Is_Entity_Name (Name (Arg))
1949 and then Is_Overloaded (Name (Arg))
1950 then
1951 Error_Msg_NE ("ambiguous call to&", Arg, Name (Arg));
1952
1953 -- Could use comments on what is going on here???
1954
1955 Get_First_Interp (Name (Arg), I, It);
1956 while Present (It.Nam) loop
1957 Error_Msg_Sloc := Sloc (It.Nam);
1958
1959 if Nkind (Parent (It.Nam)) = N_Full_Type_Declaration then
1960 Error_Msg_N ("interpretation (inherited) #!", Arg);
1961 else
1962 Error_Msg_N ("interpretation #!", Arg);
1963 end if;
1964
1965 Get_Next_Interp (I, It);
1966 end loop;
1967 end if;
1968 end Report_Ambiguous_Argument;
1969
1970 -----------------------
1971 -- Resolution_Failed --
1972 -----------------------
1973
1974 procedure Resolution_Failed is
1975 begin
1976 Patch_Up_Value (N, Typ);
1977
1978 -- Set the type to the desired one to minimize cascaded errors. Note
1979 -- that this is an approximation and does not work in all cases.
1980
1981 Set_Etype (N, Typ);
1982
1983 Debug_A_Exit ("resolving ", N, " (done, resolution failed)");
1984 Set_Is_Overloaded (N, False);
1985
1986 -- The caller will return without calling the expander, so we need
1987 -- to set the analyzed flag. Note that it is fine to set Analyzed
1988 -- to True even if we are in the middle of a shallow analysis,
1989 -- (see the spec of sem for more details) since this is an error
1990 -- situation anyway, and there is no point in repeating the
1991 -- analysis later (indeed it won't work to repeat it later, since
1992 -- we haven't got a clear resolution of which entity is being
1993 -- referenced.)
1994
1995 Set_Analyzed (N, True);
1996 return;
1997 end Resolution_Failed;
1998
1999 -- Local variables
2000
2001 Save_Ghost_Mode : constant Ghost_Mode_Type := Ghost_Mode;
2002
2003 -- Start of processing for Resolve
2004
2005 begin
2006 if N = Error then
2007 return;
2008 end if;
2009
2010 -- A declaration may be subject to pragma Ghost. Set the mode now to
2011 -- ensure that any nodes generated during analysis and expansion are
2012 -- marked as Ghost.
2013
2014 if Is_Declaration (N) then
2015 Set_Ghost_Mode (N);
2016 end if;
2017
2018 -- Access attribute on remote subprogram cannot be used for a non-remote
2019 -- access-to-subprogram type.
2020
2021 if Nkind (N) = N_Attribute_Reference
2022 and then Nam_In (Attribute_Name (N), Name_Access,
2023 Name_Unrestricted_Access,
2024 Name_Unchecked_Access)
2025 and then Comes_From_Source (N)
2026 and then Is_Entity_Name (Prefix (N))
2027 and then Is_Subprogram (Entity (Prefix (N)))
2028 and then Is_Remote_Call_Interface (Entity (Prefix (N)))
2029 and then not Is_Remote_Access_To_Subprogram_Type (Typ)
2030 then
2031 Error_Msg_N
2032 ("prefix must statically denote a non-remote subprogram", N);
2033 end if;
2034
2035 From_Lib := Comes_From_Predefined_Lib_Unit (N);
2036
2037 -- If the context is a Remote_Access_To_Subprogram, access attributes
2038 -- must be resolved with the corresponding fat pointer. There is no need
2039 -- to check for the attribute name since the return type of an
2040 -- attribute is never a remote type.
2041
2042 if Nkind (N) = N_Attribute_Reference
2043 and then Comes_From_Source (N)
2044 and then (Is_Remote_Call_Interface (Typ) or else Is_Remote_Types (Typ))
2045 then
2046 declare
2047 Attr : constant Attribute_Id :=
2048 Get_Attribute_Id (Attribute_Name (N));
2049 Pref : constant Node_Id := Prefix (N);
2050 Decl : Node_Id;
2051 Spec : Node_Id;
2052 Is_Remote : Boolean := True;
2053
2054 begin
2055 -- Check that Typ is a remote access-to-subprogram type
2056
2057 if Is_Remote_Access_To_Subprogram_Type (Typ) then
2058
2059 -- Prefix (N) must statically denote a remote subprogram
2060 -- declared in a package specification.
2061
2062 if Attr = Attribute_Access or else
2063 Attr = Attribute_Unchecked_Access or else
2064 Attr = Attribute_Unrestricted_Access
2065 then
2066 Decl := Unit_Declaration_Node (Entity (Pref));
2067
2068 if Nkind (Decl) = N_Subprogram_Body then
2069 Spec := Corresponding_Spec (Decl);
2070
2071 if Present (Spec) then
2072 Decl := Unit_Declaration_Node (Spec);
2073 end if;
2074 end if;
2075
2076 Spec := Parent (Decl);
2077
2078 if not Is_Entity_Name (Prefix (N))
2079 or else Nkind (Spec) /= N_Package_Specification
2080 or else
2081 not Is_Remote_Call_Interface (Defining_Entity (Spec))
2082 then
2083 Is_Remote := False;
2084 Error_Msg_N
2085 ("prefix must statically denote a remote subprogram ",
2086 N);
2087 end if;
2088
2089 -- If we are generating code in distributed mode, perform
2090 -- semantic checks against corresponding remote entities.
2091
2092 if Expander_Active
2093 and then Get_PCS_Name /= Name_No_DSA
2094 then
2095 Check_Subtype_Conformant
2096 (New_Id => Entity (Prefix (N)),
2097 Old_Id => Designated_Type
2098 (Corresponding_Remote_Type (Typ)),
2099 Err_Loc => N);
2100
2101 if Is_Remote then
2102 Process_Remote_AST_Attribute (N, Typ);
2103 end if;
2104 end if;
2105 end if;
2106 end if;
2107 end;
2108 end if;
2109
2110 Debug_A_Entry ("resolving ", N);
2111
2112 if Debug_Flag_V then
2113 Write_Overloads (N);
2114 end if;
2115
2116 if Comes_From_Source (N) then
2117 if Is_Fixed_Point_Type (Typ) then
2118 Check_Restriction (No_Fixed_Point, N);
2119
2120 elsif Is_Floating_Point_Type (Typ)
2121 and then Typ /= Universal_Real
2122 and then Typ /= Any_Real
2123 then
2124 Check_Restriction (No_Floating_Point, N);
2125 end if;
2126 end if;
2127
2128 -- Return if already analyzed
2129
2130 if Analyzed (N) then
2131 Debug_A_Exit ("resolving ", N, " (done, already analyzed)");
2132 Analyze_Dimension (N);
2133 Ghost_Mode := Save_Ghost_Mode;
2134 return;
2135
2136 -- Any case of Any_Type as the Etype value means that we had a
2137 -- previous error.
2138
2139 elsif Etype (N) = Any_Type then
2140 Debug_A_Exit ("resolving ", N, " (done, Etype = Any_Type)");
2141 Ghost_Mode := Save_Ghost_Mode;
2142 return;
2143 end if;
2144
2145 Check_Parameterless_Call (N);
2146
2147 -- The resolution of an Expression_With_Actions is determined by
2148 -- its Expression.
2149
2150 if Nkind (N) = N_Expression_With_Actions then
2151 Resolve (Expression (N), Typ);
2152
2153 Found := True;
2154 Expr_Type := Etype (Expression (N));
2155
2156 -- If not overloaded, then we know the type, and all that needs doing
2157 -- is to check that this type is compatible with the context.
2158
2159 elsif not Is_Overloaded (N) then
2160 Found := Covers (Typ, Etype (N));
2161 Expr_Type := Etype (N);
2162
2163 -- In the overloaded case, we must select the interpretation that
2164 -- is compatible with the context (i.e. the type passed to Resolve)
2165
2166 else
2167 -- Loop through possible interpretations
2168
2169 Get_First_Interp (N, I, It);
2170 Interp_Loop : while Present (It.Typ) loop
2171 if Debug_Flag_V then
2172 Write_Str ("Interp: ");
2173 Write_Interp (It);
2174 end if;
2175
2176 -- We are only interested in interpretations that are compatible
2177 -- with the expected type, any other interpretations are ignored.
2178
2179 if not Covers (Typ, It.Typ) then
2180 if Debug_Flag_V then
2181 Write_Str (" interpretation incompatible with context");
2182 Write_Eol;
2183 end if;
2184
2185 else
2186 -- Skip the current interpretation if it is disabled by an
2187 -- abstract operator. This action is performed only when the
2188 -- type against which we are resolving is the same as the
2189 -- type of the interpretation.
2190
2191 if Ada_Version >= Ada_2005
2192 and then It.Typ = Typ
2193 and then Typ /= Universal_Integer
2194 and then Typ /= Universal_Real
2195 and then Present (It.Abstract_Op)
2196 then
2197 if Debug_Flag_V then
2198 Write_Line ("Skip.");
2199 end if;
2200
2201 goto Continue;
2202 end if;
2203
2204 -- First matching interpretation
2205
2206 if not Found then
2207 Found := True;
2208 I1 := I;
2209 Seen := It.Nam;
2210 Expr_Type := It.Typ;
2211
2212 -- Matching interpretation that is not the first, maybe an
2213 -- error, but there are some cases where preference rules are
2214 -- used to choose between the two possibilities. These and
2215 -- some more obscure cases are handled in Disambiguate.
2216
2217 else
2218 -- If the current statement is part of a predefined library
2219 -- unit, then all interpretations which come from user level
2220 -- packages should not be considered. Check previous and
2221 -- current one.
2222
2223 if From_Lib then
2224 if not Comes_From_Predefined_Lib_Unit (It.Nam) then
2225 goto Continue;
2226
2227 elsif not Comes_From_Predefined_Lib_Unit (Seen) then
2228
2229 -- Previous interpretation must be discarded
2230
2231 I1 := I;
2232 Seen := It.Nam;
2233 Expr_Type := It.Typ;
2234 Set_Entity (N, Seen);
2235 goto Continue;
2236 end if;
2237 end if;
2238
2239 -- Otherwise apply further disambiguation steps
2240
2241 Error_Msg_Sloc := Sloc (Seen);
2242 It1 := Disambiguate (N, I1, I, Typ);
2243
2244 -- Disambiguation has succeeded. Skip the remaining
2245 -- interpretations.
2246
2247 if It1 /= No_Interp then
2248 Seen := It1.Nam;
2249 Expr_Type := It1.Typ;
2250
2251 while Present (It.Typ) loop
2252 Get_Next_Interp (I, It);
2253 end loop;
2254
2255 else
2256 -- Before we issue an ambiguity complaint, check for the
2257 -- case of a subprogram call where at least one of the
2258 -- arguments is Any_Type, and if so suppress the message,
2259 -- since it is a cascaded error. This can also happen for
2260 -- a generalized indexing operation.
2261
2262 if Nkind (N) in N_Subprogram_Call
2263 or else (Nkind (N) = N_Indexed_Component
2264 and then Present (Generalized_Indexing (N)))
2265 then
2266 declare
2267 A : Node_Id;
2268 E : Node_Id;
2269
2270 begin
2271 if Nkind (N) = N_Indexed_Component then
2272 Rewrite (N, Generalized_Indexing (N));
2273 end if;
2274
2275 A := First_Actual (N);
2276 while Present (A) loop
2277 E := A;
2278
2279 if Nkind (E) = N_Parameter_Association then
2280 E := Explicit_Actual_Parameter (E);
2281 end if;
2282
2283 if Etype (E) = Any_Type then
2284 if Debug_Flag_V then
2285 Write_Str ("Any_Type in call");
2286 Write_Eol;
2287 end if;
2288
2289 exit Interp_Loop;
2290 end if;
2291
2292 Next_Actual (A);
2293 end loop;
2294 end;
2295
2296 elsif Nkind (N) in N_Binary_Op
2297 and then (Etype (Left_Opnd (N)) = Any_Type
2298 or else Etype (Right_Opnd (N)) = Any_Type)
2299 then
2300 exit Interp_Loop;
2301
2302 elsif Nkind (N) in N_Unary_Op
2303 and then Etype (Right_Opnd (N)) = Any_Type
2304 then
2305 exit Interp_Loop;
2306 end if;
2307
2308 -- Not that special case, so issue message using the flag
2309 -- Ambiguous to control printing of the header message
2310 -- only at the start of an ambiguous set.
2311
2312 if not Ambiguous then
2313 if Nkind (N) = N_Function_Call
2314 and then Nkind (Name (N)) = N_Explicit_Dereference
2315 then
2316 Error_Msg_N
2317 ("ambiguous expression (cannot resolve indirect "
2318 & "call)!", N);
2319 else
2320 Error_Msg_NE -- CODEFIX
2321 ("ambiguous expression (cannot resolve&)!",
2322 N, It.Nam);
2323 end if;
2324
2325 Ambiguous := True;
2326
2327 if Nkind (Parent (Seen)) = N_Full_Type_Declaration then
2328 Error_Msg_N
2329 ("\\possible interpretation (inherited)#!", N);
2330 else
2331 Error_Msg_N -- CODEFIX
2332 ("\\possible interpretation#!", N);
2333 end if;
2334
2335 if Nkind (N) in N_Subprogram_Call
2336 and then Present (Parameter_Associations (N))
2337 then
2338 Report_Ambiguous_Argument;
2339 end if;
2340 end if;
2341
2342 Error_Msg_Sloc := Sloc (It.Nam);
2343
2344 -- By default, the error message refers to the candidate
2345 -- interpretation. But if it is a predefined operator, it
2346 -- is implicitly declared at the declaration of the type
2347 -- of the operand. Recover the sloc of that declaration
2348 -- for the error message.
2349
2350 if Nkind (N) in N_Op
2351 and then Scope (It.Nam) = Standard_Standard
2352 and then not Is_Overloaded (Right_Opnd (N))
2353 and then Scope (Base_Type (Etype (Right_Opnd (N)))) /=
2354 Standard_Standard
2355 then
2356 Err_Type := First_Subtype (Etype (Right_Opnd (N)));
2357
2358 if Comes_From_Source (Err_Type)
2359 and then Present (Parent (Err_Type))
2360 then
2361 Error_Msg_Sloc := Sloc (Parent (Err_Type));
2362 end if;
2363
2364 elsif Nkind (N) in N_Binary_Op
2365 and then Scope (It.Nam) = Standard_Standard
2366 and then not Is_Overloaded (Left_Opnd (N))
2367 and then Scope (Base_Type (Etype (Left_Opnd (N)))) /=
2368 Standard_Standard
2369 then
2370 Err_Type := First_Subtype (Etype (Left_Opnd (N)));
2371
2372 if Comes_From_Source (Err_Type)
2373 and then Present (Parent (Err_Type))
2374 then
2375 Error_Msg_Sloc := Sloc (Parent (Err_Type));
2376 end if;
2377
2378 -- If this is an indirect call, use the subprogram_type
2379 -- in the message, to have a meaningful location. Also
2380 -- indicate if this is an inherited operation, created
2381 -- by a type declaration.
2382
2383 elsif Nkind (N) = N_Function_Call
2384 and then Nkind (Name (N)) = N_Explicit_Dereference
2385 and then Is_Type (It.Nam)
2386 then
2387 Err_Type := It.Nam;
2388 Error_Msg_Sloc :=
2389 Sloc (Associated_Node_For_Itype (Err_Type));
2390 else
2391 Err_Type := Empty;
2392 end if;
2393
2394 if Nkind (N) in N_Op
2395 and then Scope (It.Nam) = Standard_Standard
2396 and then Present (Err_Type)
2397 then
2398 -- Special-case the message for universal_fixed
2399 -- operators, which are not declared with the type
2400 -- of the operand, but appear forever in Standard.
2401
2402 if It.Typ = Universal_Fixed
2403 and then Scope (It.Nam) = Standard_Standard
2404 then
2405 Error_Msg_N
2406 ("\\possible interpretation as universal_fixed "
2407 & "operation (RM 4.5.5 (19))", N);
2408 else
2409 Error_Msg_N
2410 ("\\possible interpretation (predefined)#!", N);
2411 end if;
2412
2413 elsif
2414 Nkind (Parent (It.Nam)) = N_Full_Type_Declaration
2415 then
2416 Error_Msg_N
2417 ("\\possible interpretation (inherited)#!", N);
2418 else
2419 Error_Msg_N -- CODEFIX
2420 ("\\possible interpretation#!", N);
2421 end if;
2422
2423 end if;
2424 end if;
2425
2426 -- We have a matching interpretation, Expr_Type is the type
2427 -- from this interpretation, and Seen is the entity.
2428
2429 -- For an operator, just set the entity name. The type will be
2430 -- set by the specific operator resolution routine.
2431
2432 if Nkind (N) in N_Op then
2433 Set_Entity (N, Seen);
2434 Generate_Reference (Seen, N);
2435
2436 elsif Nkind (N) = N_Case_Expression then
2437 Set_Etype (N, Expr_Type);
2438
2439 elsif Nkind (N) = N_Character_Literal then
2440 Set_Etype (N, Expr_Type);
2441
2442 elsif Nkind (N) = N_If_Expression then
2443 Set_Etype (N, Expr_Type);
2444
2445 -- AI05-0139-2: Expression is overloaded because type has
2446 -- implicit dereference. If type matches context, no implicit
2447 -- dereference is involved.
2448
2449 elsif Has_Implicit_Dereference (Expr_Type) then
2450 Set_Etype (N, Expr_Type);
2451 Set_Is_Overloaded (N, False);
2452 exit Interp_Loop;
2453
2454 elsif Is_Overloaded (N)
2455 and then Present (It.Nam)
2456 and then Ekind (It.Nam) = E_Discriminant
2457 and then Has_Implicit_Dereference (It.Nam)
2458 then
2459 -- If the node is a general indexing, the dereference is
2460 -- is inserted when resolving the rewritten form, else
2461 -- insert it now.
2462
2463 if Nkind (N) /= N_Indexed_Component
2464 or else No (Generalized_Indexing (N))
2465 then
2466 Build_Explicit_Dereference (N, It.Nam);
2467 end if;
2468
2469 -- For an explicit dereference, attribute reference, range,
2470 -- short-circuit form (which is not an operator node), or call
2471 -- with a name that is an explicit dereference, there is
2472 -- nothing to be done at this point.
2473
2474 elsif Nkind_In (N, N_Explicit_Dereference,
2475 N_Attribute_Reference,
2476 N_And_Then,
2477 N_Indexed_Component,
2478 N_Or_Else,
2479 N_Range,
2480 N_Selected_Component,
2481 N_Slice)
2482 or else Nkind (Name (N)) = N_Explicit_Dereference
2483 then
2484 null;
2485
2486 -- For procedure or function calls, set the type of the name,
2487 -- and also the entity pointer for the prefix.
2488
2489 elsif Nkind (N) in N_Subprogram_Call
2490 and then Is_Entity_Name (Name (N))
2491 then
2492 Set_Etype (Name (N), Expr_Type);
2493 Set_Entity (Name (N), Seen);
2494 Generate_Reference (Seen, Name (N));
2495
2496 elsif Nkind (N) = N_Function_Call
2497 and then Nkind (Name (N)) = N_Selected_Component
2498 then
2499 Set_Etype (Name (N), Expr_Type);
2500 Set_Entity (Selector_Name (Name (N)), Seen);
2501 Generate_Reference (Seen, Selector_Name (Name (N)));
2502
2503 -- For all other cases, just set the type of the Name
2504
2505 else
2506 Set_Etype (Name (N), Expr_Type);
2507 end if;
2508
2509 end if;
2510
2511 <<Continue>>
2512
2513 -- Move to next interpretation
2514
2515 exit Interp_Loop when No (It.Typ);
2516
2517 Get_Next_Interp (I, It);
2518 end loop Interp_Loop;
2519 end if;
2520
2521 -- At this stage Found indicates whether or not an acceptable
2522 -- interpretation exists. If not, then we have an error, except that if
2523 -- the context is Any_Type as a result of some other error, then we
2524 -- suppress the error report.
2525
2526 if not Found then
2527 if Typ /= Any_Type then
2528
2529 -- If type we are looking for is Void, then this is the procedure
2530 -- call case, and the error is simply that what we gave is not a
2531 -- procedure name (we think of procedure calls as expressions with
2532 -- types internally, but the user doesn't think of them this way).
2533
2534 if Typ = Standard_Void_Type then
2535
2536 -- Special case message if function used as a procedure
2537
2538 if Nkind (N) = N_Procedure_Call_Statement
2539 and then Is_Entity_Name (Name (N))
2540 and then Ekind (Entity (Name (N))) = E_Function
2541 then
2542 Error_Msg_NE
2543 ("cannot use function & in a procedure call",
2544 Name (N), Entity (Name (N)));
2545
2546 -- Otherwise give general message (not clear what cases this
2547 -- covers, but no harm in providing for them).
2548
2549 else
2550 Error_Msg_N ("expect procedure name in procedure call", N);
2551 end if;
2552
2553 Found := True;
2554
2555 -- Otherwise we do have a subexpression with the wrong type
2556
2557 -- Check for the case of an allocator which uses an access type
2558 -- instead of the designated type. This is a common error and we
2559 -- specialize the message, posting an error on the operand of the
2560 -- allocator, complaining that we expected the designated type of
2561 -- the allocator.
2562
2563 elsif Nkind (N) = N_Allocator
2564 and then Is_Access_Type (Typ)
2565 and then Is_Access_Type (Etype (N))
2566 and then Designated_Type (Etype (N)) = Typ
2567 then
2568 Wrong_Type (Expression (N), Designated_Type (Typ));
2569 Found := True;
2570
2571 -- Check for view mismatch on Null in instances, for which the
2572 -- view-swapping mechanism has no identifier.
2573
2574 elsif (In_Instance or else In_Inlined_Body)
2575 and then (Nkind (N) = N_Null)
2576 and then Is_Private_Type (Typ)
2577 and then Is_Access_Type (Full_View (Typ))
2578 then
2579 Resolve (N, Full_View (Typ));
2580 Set_Etype (N, Typ);
2581 Ghost_Mode := Save_Ghost_Mode;
2582 return;
2583
2584 -- Check for an aggregate. Sometimes we can get bogus aggregates
2585 -- from misuse of parentheses, and we are about to complain about
2586 -- the aggregate without even looking inside it.
2587
2588 -- Instead, if we have an aggregate of type Any_Composite, then
2589 -- analyze and resolve the component fields, and then only issue
2590 -- another message if we get no errors doing this (otherwise
2591 -- assume that the errors in the aggregate caused the problem).
2592
2593 elsif Nkind (N) = N_Aggregate
2594 and then Etype (N) = Any_Composite
2595 then
2596 -- Disable expansion in any case. If there is a type mismatch
2597 -- it may be fatal to try to expand the aggregate. The flag
2598 -- would otherwise be set to false when the error is posted.
2599
2600 Expander_Active := False;
2601
2602 declare
2603 procedure Check_Aggr (Aggr : Node_Id);
2604 -- Check one aggregate, and set Found to True if we have a
2605 -- definite error in any of its elements
2606
2607 procedure Check_Elmt (Aelmt : Node_Id);
2608 -- Check one element of aggregate and set Found to True if
2609 -- we definitely have an error in the element.
2610
2611 ----------------
2612 -- Check_Aggr --
2613 ----------------
2614
2615 procedure Check_Aggr (Aggr : Node_Id) is
2616 Elmt : Node_Id;
2617
2618 begin
2619 if Present (Expressions (Aggr)) then
2620 Elmt := First (Expressions (Aggr));
2621 while Present (Elmt) loop
2622 Check_Elmt (Elmt);
2623 Next (Elmt);
2624 end loop;
2625 end if;
2626
2627 if Present (Component_Associations (Aggr)) then
2628 Elmt := First (Component_Associations (Aggr));
2629 while Present (Elmt) loop
2630
2631 -- If this is a default-initialized component, then
2632 -- there is nothing to check. The box will be
2633 -- replaced by the appropriate call during late
2634 -- expansion.
2635
2636 if not Box_Present (Elmt) then
2637 Check_Elmt (Expression (Elmt));
2638 end if;
2639
2640 Next (Elmt);
2641 end loop;
2642 end if;
2643 end Check_Aggr;
2644
2645 ----------------
2646 -- Check_Elmt --
2647 ----------------
2648
2649 procedure Check_Elmt (Aelmt : Node_Id) is
2650 begin
2651 -- If we have a nested aggregate, go inside it (to
2652 -- attempt a naked analyze-resolve of the aggregate can
2653 -- cause undesirable cascaded errors). Do not resolve
2654 -- expression if it needs a type from context, as for
2655 -- integer * fixed expression.
2656
2657 if Nkind (Aelmt) = N_Aggregate then
2658 Check_Aggr (Aelmt);
2659
2660 else
2661 Analyze (Aelmt);
2662
2663 if not Is_Overloaded (Aelmt)
2664 and then Etype (Aelmt) /= Any_Fixed
2665 then
2666 Resolve (Aelmt);
2667 end if;
2668
2669 if Etype (Aelmt) = Any_Type then
2670 Found := True;
2671 end if;
2672 end if;
2673 end Check_Elmt;
2674
2675 begin
2676 Check_Aggr (N);
2677 end;
2678 end if;
2679
2680 -- Looks like we have a type error, but check for special case
2681 -- of Address wanted, integer found, with the configuration pragma
2682 -- Allow_Integer_Address active. If we have this case, introduce
2683 -- an unchecked conversion to allow the integer expression to be
2684 -- treated as an Address. The reverse case of integer wanted,
2685 -- Address found, is treated in an analogous manner.
2686
2687 if Address_Integer_Convert_OK (Typ, Etype (N)) then
2688 Rewrite (N, Unchecked_Convert_To (Typ, Relocate_Node (N)));
2689 Analyze_And_Resolve (N, Typ);
2690 Ghost_Mode := Save_Ghost_Mode;
2691 return;
2692
2693 -- Under relaxed RM semantics silently replace occurrences of null
2694 -- by System.Address_Null.
2695
2696 elsif Null_To_Null_Address_Convert_OK (N, Typ) then
2697 Replace_Null_By_Null_Address (N);
2698 Analyze_And_Resolve (N, Typ);
2699 return;
2700 end if;
2701
2702 -- That special Allow_Integer_Address check did not apply, so we
2703 -- have a real type error. If an error message was issued already,
2704 -- Found got reset to True, so if it's still False, issue standard
2705 -- Wrong_Type message.
2706
2707 if not Found then
2708 if Is_Overloaded (N) and then Nkind (N) = N_Function_Call then
2709 declare
2710 Subp_Name : Node_Id;
2711
2712 begin
2713 if Is_Entity_Name (Name (N)) then
2714 Subp_Name := Name (N);
2715
2716 elsif Nkind (Name (N)) = N_Selected_Component then
2717
2718 -- Protected operation: retrieve operation name
2719
2720 Subp_Name := Selector_Name (Name (N));
2721
2722 else
2723 raise Program_Error;
2724 end if;
2725
2726 Error_Msg_Node_2 := Typ;
2727 Error_Msg_NE
2728 ("no visible interpretation of& "
2729 & "matches expected type&", N, Subp_Name);
2730 end;
2731
2732 if All_Errors_Mode then
2733 declare
2734 Index : Interp_Index;
2735 It : Interp;
2736
2737 begin
2738 Error_Msg_N ("\\possible interpretations:", N);
2739
2740 Get_First_Interp (Name (N), Index, It);
2741 while Present (It.Nam) loop
2742 Error_Msg_Sloc := Sloc (It.Nam);
2743 Error_Msg_Node_2 := It.Nam;
2744 Error_Msg_NE
2745 ("\\ type& for & declared#", N, It.Typ);
2746 Get_Next_Interp (Index, It);
2747 end loop;
2748 end;
2749
2750 else
2751 Error_Msg_N ("\use -gnatf for details", N);
2752 end if;
2753
2754 else
2755 Wrong_Type (N, Typ);
2756 end if;
2757 end if;
2758 end if;
2759
2760 Resolution_Failed;
2761 Ghost_Mode := Save_Ghost_Mode;
2762 return;
2763
2764 -- Test if we have more than one interpretation for the context
2765
2766 elsif Ambiguous then
2767 Resolution_Failed;
2768 Ghost_Mode := Save_Ghost_Mode;
2769 return;
2770
2771 -- Only one intepretation
2772
2773 else
2774 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2775 -- the "+" on T is abstract, and the operands are of universal type,
2776 -- the above code will have (incorrectly) resolved the "+" to the
2777 -- universal one in Standard. Therefore check for this case and give
2778 -- an error. We can't do this earlier, because it would cause legal
2779 -- cases to get errors (when some other type has an abstract "+").
2780
2781 if Ada_Version >= Ada_2005
2782 and then Nkind (N) in N_Op
2783 and then Is_Overloaded (N)
2784 and then Is_Universal_Numeric_Type (Etype (Entity (N)))
2785 then
2786 Get_First_Interp (N, I, It);
2787 while Present (It.Typ) loop
2788 if Present (It.Abstract_Op) and then
2789 Etype (It.Abstract_Op) = Typ
2790 then
2791 Error_Msg_NE
2792 ("cannot call abstract subprogram &!", N, It.Abstract_Op);
2793 return;
2794 end if;
2795
2796 Get_Next_Interp (I, It);
2797 end loop;
2798 end if;
2799
2800 -- Here we have an acceptable interpretation for the context
2801
2802 -- Propagate type information and normalize tree for various
2803 -- predefined operations. If the context only imposes a class of
2804 -- types, rather than a specific type, propagate the actual type
2805 -- downward.
2806
2807 if Typ = Any_Integer or else
2808 Typ = Any_Boolean or else
2809 Typ = Any_Modular or else
2810 Typ = Any_Real or else
2811 Typ = Any_Discrete
2812 then
2813 Ctx_Type := Expr_Type;
2814
2815 -- Any_Fixed is legal in a real context only if a specific fixed-
2816 -- point type is imposed. If Norman Cohen can be confused by this,
2817 -- it deserves a separate message.
2818
2819 if Typ = Any_Real
2820 and then Expr_Type = Any_Fixed
2821 then
2822 Error_Msg_N ("illegal context for mixed mode operation", N);
2823 Set_Etype (N, Universal_Real);
2824 Ctx_Type := Universal_Real;
2825 end if;
2826 end if;
2827
2828 -- A user-defined operator is transformed into a function call at
2829 -- this point, so that further processing knows that operators are
2830 -- really operators (i.e. are predefined operators). User-defined
2831 -- operators that are intrinsic are just renamings of the predefined
2832 -- ones, and need not be turned into calls either, but if they rename
2833 -- a different operator, we must transform the node accordingly.
2834 -- Instantiations of Unchecked_Conversion are intrinsic but are
2835 -- treated as functions, even if given an operator designator.
2836
2837 if Nkind (N) in N_Op
2838 and then Present (Entity (N))
2839 and then Ekind (Entity (N)) /= E_Operator
2840 then
2841
2842 if not Is_Predefined_Op (Entity (N)) then
2843 Rewrite_Operator_As_Call (N, Entity (N));
2844
2845 elsif Present (Alias (Entity (N)))
2846 and then
2847 Nkind (Parent (Parent (Entity (N)))) =
2848 N_Subprogram_Renaming_Declaration
2849 then
2850 Rewrite_Renamed_Operator (N, Alias (Entity (N)), Typ);
2851
2852 -- If the node is rewritten, it will be fully resolved in
2853 -- Rewrite_Renamed_Operator.
2854
2855 if Analyzed (N) then
2856 Ghost_Mode := Save_Ghost_Mode;
2857 return;
2858 end if;
2859 end if;
2860 end if;
2861
2862 case N_Subexpr'(Nkind (N)) is
2863
2864 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2865
2866 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2867
2868 when N_Short_Circuit
2869 => Resolve_Short_Circuit (N, Ctx_Type);
2870
2871 when N_Attribute_Reference
2872 => Resolve_Attribute (N, Ctx_Type);
2873
2874 when N_Case_Expression
2875 => Resolve_Case_Expression (N, Ctx_Type);
2876
2877 when N_Character_Literal
2878 => Resolve_Character_Literal (N, Ctx_Type);
2879
2880 when N_Expanded_Name
2881 => Resolve_Entity_Name (N, Ctx_Type);
2882
2883 when N_Explicit_Dereference
2884 => Resolve_Explicit_Dereference (N, Ctx_Type);
2885
2886 when N_Expression_With_Actions
2887 => Resolve_Expression_With_Actions (N, Ctx_Type);
2888
2889 when N_Extension_Aggregate
2890 => Resolve_Extension_Aggregate (N, Ctx_Type);
2891
2892 when N_Function_Call
2893 => Resolve_Call (N, Ctx_Type);
2894
2895 when N_Identifier
2896 => Resolve_Entity_Name (N, Ctx_Type);
2897
2898 when N_If_Expression
2899 => Resolve_If_Expression (N, Ctx_Type);
2900
2901 when N_Indexed_Component
2902 => Resolve_Indexed_Component (N, Ctx_Type);
2903
2904 when N_Integer_Literal
2905 => Resolve_Integer_Literal (N, Ctx_Type);
2906
2907 when N_Membership_Test
2908 => Resolve_Membership_Op (N, Ctx_Type);
2909
2910 when N_Null => Resolve_Null (N, Ctx_Type);
2911
2912 when N_Op_And | N_Op_Or | N_Op_Xor
2913 => Resolve_Logical_Op (N, Ctx_Type);
2914
2915 when N_Op_Eq | N_Op_Ne
2916 => Resolve_Equality_Op (N, Ctx_Type);
2917
2918 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2919 => Resolve_Comparison_Op (N, Ctx_Type);
2920
2921 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2922
2923 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2924 N_Op_Divide | N_Op_Mod | N_Op_Rem
2925
2926 => Resolve_Arithmetic_Op (N, Ctx_Type);
2927
2928 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2929
2930 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2931
2932 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2933 => Resolve_Unary_Op (N, Ctx_Type);
2934
2935 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2936
2937 when N_Procedure_Call_Statement
2938 => Resolve_Call (N, Ctx_Type);
2939
2940 when N_Operator_Symbol
2941 => Resolve_Operator_Symbol (N, Ctx_Type);
2942
2943 when N_Qualified_Expression
2944 => Resolve_Qualified_Expression (N, Ctx_Type);
2945
2946 -- Why is the following null, needs a comment ???
2947
2948 when N_Quantified_Expression
2949 => null;
2950
2951 when N_Raise_Expression
2952 => Resolve_Raise_Expression (N, Ctx_Type);
2953
2954 when N_Raise_xxx_Error
2955 => Set_Etype (N, Ctx_Type);
2956
2957 when N_Range => Resolve_Range (N, Ctx_Type);
2958
2959 when N_Real_Literal
2960 => Resolve_Real_Literal (N, Ctx_Type);
2961
2962 when N_Reference => Resolve_Reference (N, Ctx_Type);
2963
2964 when N_Selected_Component
2965 => Resolve_Selected_Component (N, Ctx_Type);
2966
2967 when N_Slice => Resolve_Slice (N, Ctx_Type);
2968
2969 when N_String_Literal
2970 => Resolve_String_Literal (N, Ctx_Type);
2971
2972 when N_Type_Conversion
2973 => Resolve_Type_Conversion (N, Ctx_Type);
2974
2975 when N_Unchecked_Expression =>
2976 Resolve_Unchecked_Expression (N, Ctx_Type);
2977
2978 when N_Unchecked_Type_Conversion =>
2979 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2980 end case;
2981
2982 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2983 -- expression of an anonymous access type that occurs in the context
2984 -- of a named general access type, except when the expression is that
2985 -- of a membership test. This ensures proper legality checking in
2986 -- terms of allowed conversions (expressions that would be illegal to
2987 -- convert implicitly are allowed in membership tests).
2988
2989 if Ada_Version >= Ada_2012
2990 and then Ekind (Ctx_Type) = E_General_Access_Type
2991 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2992 and then Nkind (Parent (N)) not in N_Membership_Test
2993 then
2994 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2995 Analyze_And_Resolve (N, Ctx_Type);
2996 end if;
2997
2998 -- If the subexpression was replaced by a non-subexpression, then
2999 -- all we do is to expand it. The only legitimate case we know of
3000 -- is converting procedure call statement to entry call statements,
3001 -- but there may be others, so we are making this test general.
3002
3003 if Nkind (N) not in N_Subexpr then
3004 Debug_A_Exit ("resolving ", N, " (done)");
3005 Expand (N);
3006 Ghost_Mode := Save_Ghost_Mode;
3007 return;
3008 end if;
3009
3010 -- The expression is definitely NOT overloaded at this point, so
3011 -- we reset the Is_Overloaded flag to avoid any confusion when
3012 -- reanalyzing the node.
3013
3014 Set_Is_Overloaded (N, False);
3015
3016 -- Freeze expression type, entity if it is a name, and designated
3017 -- type if it is an allocator (RM 13.14(10,11,13)).
3018
3019 -- Now that the resolution of the type of the node is complete, and
3020 -- we did not detect an error, we can expand this node. We skip the
3021 -- expand call if we are in a default expression, see section
3022 -- "Handling of Default Expressions" in Sem spec.
3023
3024 Debug_A_Exit ("resolving ", N, " (done)");
3025
3026 -- We unconditionally freeze the expression, even if we are in
3027 -- default expression mode (the Freeze_Expression routine tests this
3028 -- flag and only freezes static types if it is set).
3029
3030 -- Ada 2012 (AI05-177): The declaration of an expression function
3031 -- does not cause freezing, but we never reach here in that case.
3032 -- Here we are resolving the corresponding expanded body, so we do
3033 -- need to perform normal freezing.
3034
3035 Freeze_Expression (N);
3036
3037 -- Now we can do the expansion
3038
3039 Expand (N);
3040 end if;
3041
3042 Ghost_Mode := Save_Ghost_Mode;
3043 end Resolve;
3044
3045 -------------
3046 -- Resolve --
3047 -------------
3048
3049 -- Version with check(s) suppressed
3050
3051 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3052 begin
3053 if Suppress = All_Checks then
3054 declare
3055 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3056 begin
3057 Scope_Suppress.Suppress := (others => True);
3058 Resolve (N, Typ);
3059 Scope_Suppress.Suppress := Sva;
3060 end;
3061
3062 else
3063 declare
3064 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3065 begin
3066 Scope_Suppress.Suppress (Suppress) := True;
3067 Resolve (N, Typ);
3068 Scope_Suppress.Suppress (Suppress) := Svg;
3069 end;
3070 end if;
3071 end Resolve;
3072
3073 -------------
3074 -- Resolve --
3075 -------------
3076
3077 -- Version with implicit type
3078
3079 procedure Resolve (N : Node_Id) is
3080 begin
3081 Resolve (N, Etype (N));
3082 end Resolve;
3083
3084 ---------------------
3085 -- Resolve_Actuals --
3086 ---------------------
3087
3088 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3089 Loc : constant Source_Ptr := Sloc (N);
3090 A : Node_Id;
3091 A_Id : Entity_Id;
3092 A_Typ : Entity_Id;
3093 F : Entity_Id;
3094 F_Typ : Entity_Id;
3095 Prev : Node_Id := Empty;
3096 Orig_A : Node_Id;
3097 Real_F : Entity_Id;
3098
3099 Real_Subp : Entity_Id;
3100 -- If the subprogram being called is an inherited operation for
3101 -- a formal derived type in an instance, Real_Subp is the subprogram
3102 -- that will be called. It may have different formal names than the
3103 -- operation of the formal in the generic, so after actual is resolved
3104 -- the name of the actual in a named association must carry the name
3105 -- of the actual of the subprogram being called.
3106
3107 procedure Check_Aliased_Parameter;
3108 -- Check rules on aliased parameters and related accessibility rules
3109 -- in (RM 3.10.2 (10.2-10.4)).
3110
3111 procedure Check_Argument_Order;
3112 -- Performs a check for the case where the actuals are all simple
3113 -- identifiers that correspond to the formal names, but in the wrong
3114 -- order, which is considered suspicious and cause for a warning.
3115
3116 procedure Check_Prefixed_Call;
3117 -- If the original node is an overloaded call in prefix notation,
3118 -- insert an 'Access or a dereference as needed over the first actual.
3119 -- Try_Object_Operation has already verified that there is a valid
3120 -- interpretation, but the form of the actual can only be determined
3121 -- once the primitive operation is identified.
3122
3123 procedure Flag_Effectively_Volatile_Objects (Expr : Node_Id);
3124 -- Emit an error concerning the illegal usage of an effectively volatile
3125 -- object in interfering context (SPARK RM 7.13(12)).
3126
3127 procedure Insert_Default;
3128 -- If the actual is missing in a call, insert in the actuals list
3129 -- an instance of the default expression. The insertion is always
3130 -- a named association.
3131
3132 procedure Property_Error
3133 (Var : Node_Id;
3134 Var_Id : Entity_Id;
3135 Prop_Nam : Name_Id);
3136 -- Emit an error concerning variable Var with entity Var_Id that has
3137 -- enabled property Prop_Nam when it acts as an actual parameter in a
3138 -- call and the corresponding formal parameter is of mode IN.
3139
3140 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean;
3141 -- Check whether T1 and T2, or their full views, are derived from a
3142 -- common type. Used to enforce the restrictions on array conversions
3143 -- of AI95-00246.
3144
3145 function Static_Concatenation (N : Node_Id) return Boolean;
3146 -- Predicate to determine whether an actual that is a concatenation
3147 -- will be evaluated statically and does not need a transient scope.
3148 -- This must be determined before the actual is resolved and expanded
3149 -- because if needed the transient scope must be introduced earlier.
3150
3151 -----------------------------
3152 -- Check_Aliased_Parameter --
3153 -----------------------------
3154
3155 procedure Check_Aliased_Parameter is
3156 Nominal_Subt : Entity_Id;
3157
3158 begin
3159 if Is_Aliased (F) then
3160 if Is_Tagged_Type (A_Typ) then
3161 null;
3162
3163 elsif Is_Aliased_View (A) then
3164 if Is_Constr_Subt_For_U_Nominal (A_Typ) then
3165 Nominal_Subt := Base_Type (A_Typ);
3166 else
3167 Nominal_Subt := A_Typ;
3168 end if;
3169
3170 if Subtypes_Statically_Match (F_Typ, Nominal_Subt) then
3171 null;
3172
3173 -- In a generic body assume the worst for generic formals:
3174 -- they can have a constrained partial view (AI05-041).
3175
3176 elsif Has_Discriminants (F_Typ)
3177 and then not Is_Constrained (F_Typ)
3178 and then not Has_Constrained_Partial_View (F_Typ)
3179 and then not Is_Generic_Type (F_Typ)
3180 then
3181 null;
3182
3183 else
3184 Error_Msg_NE ("untagged actual does not match "
3185 & "aliased formal&", A, F);
3186 end if;
3187
3188 else
3189 Error_Msg_NE ("actual for aliased formal& must be "
3190 & "aliased object", A, F);
3191 end if;
3192
3193 if Ekind (Nam) = E_Procedure then
3194 null;
3195
3196 elsif Ekind (Etype (Nam)) = E_Anonymous_Access_Type then
3197 if Nkind (Parent (N)) = N_Type_Conversion
3198 and then Type_Access_Level (Etype (Parent (N))) <
3199 Object_Access_Level (A)
3200 then
3201 Error_Msg_N ("aliased actual has wrong accessibility", A);
3202 end if;
3203
3204 elsif Nkind (Parent (N)) = N_Qualified_Expression
3205 and then Nkind (Parent (Parent (N))) = N_Allocator
3206 and then Type_Access_Level (Etype (Parent (Parent (N)))) <
3207 Object_Access_Level (A)
3208 then
3209 Error_Msg_N
3210 ("aliased actual in allocator has wrong accessibility", A);
3211 end if;
3212 end if;
3213 end Check_Aliased_Parameter;
3214
3215 --------------------------
3216 -- Check_Argument_Order --
3217 --------------------------
3218
3219 procedure Check_Argument_Order is
3220 begin
3221 -- Nothing to do if no parameters, or original node is neither a
3222 -- function call nor a procedure call statement (happens in the
3223 -- operator-transformed-to-function call case), or the call does
3224 -- not come from source, or this warning is off.
3225
3226 if not Warn_On_Parameter_Order
3227 or else No (Parameter_Associations (N))
3228 or else Nkind (Original_Node (N)) not in N_Subprogram_Call
3229 or else not Comes_From_Source (N)
3230 then
3231 return;
3232 end if;
3233
3234 declare
3235 Nargs : constant Nat := List_Length (Parameter_Associations (N));
3236
3237 begin
3238 -- Nothing to do if only one parameter
3239
3240 if Nargs < 2 then
3241 return;
3242 end if;
3243
3244 -- Here if at least two arguments
3245
3246 declare
3247 Actuals : array (1 .. Nargs) of Node_Id;
3248 Actual : Node_Id;
3249 Formal : Node_Id;
3250
3251 Wrong_Order : Boolean := False;
3252 -- Set True if an out of order case is found
3253
3254 begin
3255 -- Collect identifier names of actuals, fail if any actual is
3256 -- not a simple identifier, and record max length of name.
3257
3258 Actual := First (Parameter_Associations (N));
3259 for J in Actuals'Range loop
3260 if Nkind (Actual) /= N_Identifier then
3261 return;
3262 else
3263 Actuals (J) := Actual;
3264 Next (Actual);
3265 end if;
3266 end loop;
3267
3268 -- If we got this far, all actuals are identifiers and the list
3269 -- of their names is stored in the Actuals array.
3270
3271 Formal := First_Formal (Nam);
3272 for J in Actuals'Range loop
3273
3274 -- If we ran out of formals, that's odd, probably an error
3275 -- which will be detected elsewhere, but abandon the search.
3276
3277 if No (Formal) then
3278 return;
3279 end if;
3280
3281 -- If name matches and is in order OK
3282
3283 if Chars (Formal) = Chars (Actuals (J)) then
3284 null;
3285
3286 else
3287 -- If no match, see if it is elsewhere in list and if so
3288 -- flag potential wrong order if type is compatible.
3289
3290 for K in Actuals'Range loop
3291 if Chars (Formal) = Chars (Actuals (K))
3292 and then
3293 Has_Compatible_Type (Actuals (K), Etype (Formal))
3294 then
3295 Wrong_Order := True;
3296 goto Continue;
3297 end if;
3298 end loop;
3299
3300 -- No match
3301
3302 return;
3303 end if;
3304
3305 <<Continue>> Next_Formal (Formal);
3306 end loop;
3307
3308 -- If Formals left over, also probably an error, skip warning
3309
3310 if Present (Formal) then
3311 return;
3312 end if;
3313
3314 -- Here we give the warning if something was out of order
3315
3316 if Wrong_Order then
3317 Error_Msg_N
3318 ("?P?actuals for this call may be in wrong order", N);
3319 end if;
3320 end;
3321 end;
3322 end Check_Argument_Order;
3323
3324 -------------------------
3325 -- Check_Prefixed_Call --
3326 -------------------------
3327
3328 procedure Check_Prefixed_Call is
3329 Act : constant Node_Id := First_Actual (N);
3330 A_Type : constant Entity_Id := Etype (Act);
3331 F_Type : constant Entity_Id := Etype (First_Formal (Nam));
3332 Orig : constant Node_Id := Original_Node (N);
3333 New_A : Node_Id;
3334
3335 begin
3336 -- Check whether the call is a prefixed call, with or without
3337 -- additional actuals.
3338
3339 if Nkind (Orig) = N_Selected_Component
3340 or else
3341 (Nkind (Orig) = N_Indexed_Component
3342 and then Nkind (Prefix (Orig)) = N_Selected_Component
3343 and then Is_Entity_Name (Prefix (Prefix (Orig)))
3344 and then Is_Entity_Name (Act)
3345 and then Chars (Act) = Chars (Prefix (Prefix (Orig))))
3346 then
3347 if Is_Access_Type (A_Type)
3348 and then not Is_Access_Type (F_Type)
3349 then
3350 -- Introduce dereference on object in prefix
3351
3352 New_A :=
3353 Make_Explicit_Dereference (Sloc (Act),
3354 Prefix => Relocate_Node (Act));
3355 Rewrite (Act, New_A);
3356 Analyze (Act);
3357
3358 elsif Is_Access_Type (F_Type)
3359 and then not Is_Access_Type (A_Type)
3360 then
3361 -- Introduce an implicit 'Access in prefix
3362
3363 if not Is_Aliased_View (Act) then
3364 Error_Msg_NE
3365 ("object in prefixed call to& must be aliased "
3366 & "(RM 4.1.3 (13 1/2))",
3367 Prefix (Act), Nam);
3368 end if;
3369
3370 Rewrite (Act,
3371 Make_Attribute_Reference (Loc,
3372 Attribute_Name => Name_Access,
3373 Prefix => Relocate_Node (Act)));
3374 end if;
3375
3376 Analyze (Act);
3377 end if;
3378 end Check_Prefixed_Call;
3379
3380 ---------------------------------------
3381 -- Flag_Effectively_Volatile_Objects --
3382 ---------------------------------------
3383
3384 procedure Flag_Effectively_Volatile_Objects (Expr : Node_Id) is
3385 function Flag_Object (N : Node_Id) return Traverse_Result;
3386 -- Determine whether arbitrary node N denotes an effectively volatile
3387 -- object and if it does, emit an error.
3388
3389 -----------------
3390 -- Flag_Object --
3391 -----------------
3392
3393 function Flag_Object (N : Node_Id) return Traverse_Result is
3394 Id : Entity_Id;
3395
3396 begin
3397 -- Do not consider nested function calls because they have already
3398 -- been processed during their own resolution.
3399
3400 if Nkind (N) = N_Function_Call then
3401 return Skip;
3402
3403 elsif Is_Entity_Name (N) and then Present (Entity (N)) then
3404 Id := Entity (N);
3405
3406 if Is_Object (Id)
3407 and then Is_Effectively_Volatile (Id)
3408 and then (Async_Writers_Enabled (Id)
3409 or else Effective_Reads_Enabled (Id))
3410 then
3411 Error_Msg_N
3412 ("volatile object cannot appear in this context (SPARK "
3413 & "RM 7.1.3(11))", N);
3414 return Skip;
3415 end if;
3416 end if;
3417
3418 return OK;
3419 end Flag_Object;
3420
3421 procedure Flag_Objects is new Traverse_Proc (Flag_Object);
3422
3423 -- Start of processing for Flag_Effectively_Volatile_Objects
3424
3425 begin
3426 Flag_Objects (Expr);
3427 end Flag_Effectively_Volatile_Objects;
3428
3429 --------------------
3430 -- Insert_Default --
3431 --------------------
3432
3433 procedure Insert_Default is
3434 Actval : Node_Id;
3435 Assoc : Node_Id;
3436
3437 begin
3438 -- Missing argument in call, nothing to insert
3439
3440 if No (Default_Value (F)) then
3441 return;
3442
3443 else
3444 -- Note that we do a full New_Copy_Tree, so that any associated
3445 -- Itypes are properly copied. This may not be needed any more,
3446 -- but it does no harm as a safety measure. Defaults of a generic
3447 -- formal may be out of bounds of the corresponding actual (see
3448 -- cc1311b) and an additional check may be required.
3449
3450 Actval :=
3451 New_Copy_Tree
3452 (Default_Value (F),
3453 New_Scope => Current_Scope,
3454 New_Sloc => Loc);
3455
3456 -- Propagate dimension information, if any.
3457
3458 Copy_Dimensions (Default_Value (F), Actval);
3459
3460 if Is_Concurrent_Type (Scope (Nam))
3461 and then Has_Discriminants (Scope (Nam))
3462 then
3463 Replace_Actual_Discriminants (N, Actval);
3464 end if;
3465
3466 if Is_Overloadable (Nam)
3467 and then Present (Alias (Nam))
3468 then
3469 if Base_Type (Etype (F)) /= Base_Type (Etype (Actval))
3470 and then not Is_Tagged_Type (Etype (F))
3471 then
3472 -- If default is a real literal, do not introduce a
3473 -- conversion whose effect may depend on the run-time
3474 -- size of universal real.
3475
3476 if Nkind (Actval) = N_Real_Literal then
3477 Set_Etype (Actval, Base_Type (Etype (F)));
3478 else
3479 Actval := Unchecked_Convert_To (Etype (F), Actval);
3480 end if;
3481 end if;
3482
3483 if Is_Scalar_Type (Etype (F)) then
3484 Enable_Range_Check (Actval);
3485 end if;
3486
3487 Set_Parent (Actval, N);
3488
3489 -- Resolve aggregates with their base type, to avoid scope
3490 -- anomalies: the subtype was first built in the subprogram
3491 -- declaration, and the current call may be nested.
3492
3493 if Nkind (Actval) = N_Aggregate then
3494 Analyze_And_Resolve (Actval, Etype (F));
3495 else
3496 Analyze_And_Resolve (Actval, Etype (Actval));
3497 end if;
3498
3499 else
3500 Set_Parent (Actval, N);
3501
3502 -- See note above concerning aggregates
3503
3504 if Nkind (Actval) = N_Aggregate
3505 and then Has_Discriminants (Etype (Actval))
3506 then
3507 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
3508
3509 -- Resolve entities with their own type, which may differ from
3510 -- the type of a reference in a generic context (the view
3511 -- swapping mechanism did not anticipate the re-analysis of
3512 -- default values in calls).
3513
3514 elsif Is_Entity_Name (Actval) then
3515 Analyze_And_Resolve (Actval, Etype (Entity (Actval)));
3516
3517 else
3518 Analyze_And_Resolve (Actval, Etype (Actval));
3519 end if;
3520 end if;
3521
3522 -- If default is a tag indeterminate function call, propagate tag
3523 -- to obtain proper dispatching.
3524
3525 if Is_Controlling_Formal (F)
3526 and then Nkind (Default_Value (F)) = N_Function_Call
3527 then
3528 Set_Is_Controlling_Actual (Actval);
3529 end if;
3530 end if;
3531
3532 -- If the default expression raises constraint error, then just
3533 -- silently replace it with an N_Raise_Constraint_Error node, since
3534 -- we already gave the warning on the subprogram spec. If node is
3535 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3536 -- the warnings removal machinery.
3537
3538 if Raises_Constraint_Error (Actval)
3539 and then Nkind (Actval) /= N_Raise_Constraint_Error
3540 then
3541 Rewrite (Actval,
3542 Make_Raise_Constraint_Error (Loc,
3543 Reason => CE_Range_Check_Failed));
3544 Set_Raises_Constraint_Error (Actval);
3545 Set_Etype (Actval, Etype (F));
3546 end if;
3547
3548 Assoc :=
3549 Make_Parameter_Association (Loc,
3550 Explicit_Actual_Parameter => Actval,
3551 Selector_Name => Make_Identifier (Loc, Chars (F)));
3552
3553 -- Case of insertion is first named actual
3554
3555 if No (Prev) or else
3556 Nkind (Parent (Prev)) /= N_Parameter_Association
3557 then
3558 Set_Next_Named_Actual (Assoc, First_Named_Actual (N));
3559 Set_First_Named_Actual (N, Actval);
3560
3561 if No (Prev) then
3562 if No (Parameter_Associations (N)) then
3563 Set_Parameter_Associations (N, New_List (Assoc));
3564 else
3565 Append (Assoc, Parameter_Associations (N));
3566 end if;
3567
3568 else
3569 Insert_After (Prev, Assoc);
3570 end if;
3571
3572 -- Case of insertion is not first named actual
3573
3574 else
3575 Set_Next_Named_Actual
3576 (Assoc, Next_Named_Actual (Parent (Prev)));
3577 Set_Next_Named_Actual (Parent (Prev), Actval);
3578 Append (Assoc, Parameter_Associations (N));
3579 end if;
3580
3581 Mark_Rewrite_Insertion (Assoc);
3582 Mark_Rewrite_Insertion (Actval);
3583
3584 Prev := Actval;
3585 end Insert_Default;
3586
3587 --------------------
3588 -- Property_Error --
3589 --------------------
3590
3591 procedure Property_Error
3592 (Var : Node_Id;
3593 Var_Id : Entity_Id;
3594 Prop_Nam : Name_Id)
3595 is
3596 begin
3597 Error_Msg_Name_1 := Prop_Nam;
3598 Error_Msg_NE
3599 ("external variable & with enabled property % cannot appear as "
3600 & "actual in procedure call (SPARK RM 7.1.3(10))", Var, Var_Id);
3601 Error_Msg_N ("\\corresponding formal parameter has mode In", Var);
3602 end Property_Error;
3603
3604 -------------------
3605 -- Same_Ancestor --
3606 -------------------
3607
3608 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean is
3609 FT1 : Entity_Id := T1;
3610 FT2 : Entity_Id := T2;
3611
3612 begin
3613 if Is_Private_Type (T1)
3614 and then Present (Full_View (T1))
3615 then
3616 FT1 := Full_View (T1);
3617 end if;
3618
3619 if Is_Private_Type (T2)
3620 and then Present (Full_View (T2))
3621 then
3622 FT2 := Full_View (T2);
3623 end if;
3624
3625 return Root_Type (Base_Type (FT1)) = Root_Type (Base_Type (FT2));
3626 end Same_Ancestor;
3627
3628 --------------------------
3629 -- Static_Concatenation --
3630 --------------------------
3631
3632 function Static_Concatenation (N : Node_Id) return Boolean is
3633 begin
3634 case Nkind (N) is
3635 when N_String_Literal =>
3636 return True;
3637
3638 when N_Op_Concat =>
3639
3640 -- Concatenation is static when both operands are static and
3641 -- the concatenation operator is a predefined one.
3642
3643 return Scope (Entity (N)) = Standard_Standard
3644 and then
3645 Static_Concatenation (Left_Opnd (N))
3646 and then
3647 Static_Concatenation (Right_Opnd (N));
3648
3649 when others =>
3650 if Is_Entity_Name (N) then
3651 declare
3652 Ent : constant Entity_Id := Entity (N);
3653 begin
3654 return Ekind (Ent) = E_Constant
3655 and then Present (Constant_Value (Ent))
3656 and then
3657 Is_OK_Static_Expression (Constant_Value (Ent));
3658 end;
3659
3660 else
3661 return False;
3662 end if;
3663 end case;
3664 end Static_Concatenation;
3665
3666 -- Start of processing for Resolve_Actuals
3667
3668 begin
3669 Check_Argument_Order;
3670
3671 if Is_Overloadable (Nam)
3672 and then Is_Inherited_Operation (Nam)
3673 and then In_Instance
3674 and then Present (Alias (Nam))
3675 and then Present (Overridden_Operation (Alias (Nam)))
3676 then
3677 Real_Subp := Alias (Nam);
3678 else
3679 Real_Subp := Empty;
3680 end if;
3681
3682 if Present (First_Actual (N)) then
3683 Check_Prefixed_Call;
3684 end if;
3685
3686 A := First_Actual (N);
3687 F := First_Formal (Nam);
3688
3689 if Present (Real_Subp) then
3690 Real_F := First_Formal (Real_Subp);
3691 end if;
3692
3693 while Present (F) loop
3694 if No (A) and then Needs_No_Actuals (Nam) then
3695 null;
3696
3697 -- If we have an error in any actual or formal, indicated by a type
3698 -- of Any_Type, then abandon resolution attempt, and set result type
3699 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3700 -- type is imposed from context.
3701
3702 elsif (Present (A) and then Etype (A) = Any_Type)
3703 or else Etype (F) = Any_Type
3704 then
3705 if Nkind (A) /= N_Raise_Expression then
3706 Set_Etype (N, Any_Type);
3707 return;
3708 end if;
3709 end if;
3710
3711 -- Case where actual is present
3712
3713 -- If the actual is an entity, generate a reference to it now. We
3714 -- do this before the actual is resolved, because a formal of some
3715 -- protected subprogram, or a task discriminant, will be rewritten
3716 -- during expansion, and the source entity reference may be lost.
3717
3718 if Present (A)
3719 and then Is_Entity_Name (A)
3720 and then Comes_From_Source (A)
3721 then
3722 Orig_A := Entity (A);
3723
3724 if Present (Orig_A) then
3725 if Is_Formal (Orig_A)
3726 and then Ekind (F) /= E_In_Parameter
3727 then
3728 Generate_Reference (Orig_A, A, 'm');
3729
3730 elsif not Is_Overloaded (A) then
3731 if Ekind (F) /= E_Out_Parameter then
3732 Generate_Reference (Orig_A, A);
3733
3734 -- RM 6.4.1(12): For an out parameter that is passed by
3735 -- copy, the formal parameter object is created, and:
3736
3737 -- * For an access type, the formal parameter is initialized
3738 -- from the value of the actual, without checking that the
3739 -- value satisfies any constraint, any predicate, or any
3740 -- exclusion of the null value.
3741
3742 -- * For a scalar type that has the Default_Value aspect
3743 -- specified, the formal parameter is initialized from the
3744 -- value of the actual, without checking that the value
3745 -- satisfies any constraint or any predicate.
3746 -- I do not understand why this case is included??? this is
3747 -- not a case where an OUT parameter is treated as IN OUT.
3748
3749 -- * For a composite type with discriminants or that has
3750 -- implicit initial values for any subcomponents, the
3751 -- behavior is as for an in out parameter passed by copy.
3752
3753 -- Hence for these cases we generate the read reference now
3754 -- (the write reference will be generated later by
3755 -- Note_Possible_Modification).
3756
3757 elsif Is_By_Copy_Type (Etype (F))
3758 and then
3759 (Is_Access_Type (Etype (F))
3760 or else
3761 (Is_Scalar_Type (Etype (F))
3762 and then
3763 Present (Default_Aspect_Value (Etype (F))))
3764 or else
3765 (Is_Composite_Type (Etype (F))
3766 and then (Has_Discriminants (Etype (F))
3767 or else Is_Partially_Initialized_Type
3768 (Etype (F)))))
3769 then
3770 Generate_Reference (Orig_A, A);
3771 end if;
3772 end if;
3773 end if;
3774 end if;
3775
3776 if Present (A)
3777 and then (Nkind (Parent (A)) /= N_Parameter_Association
3778 or else Chars (Selector_Name (Parent (A))) = Chars (F))
3779 then
3780 -- If style checking mode on, check match of formal name
3781
3782 if Style_Check then
3783 if Nkind (Parent (A)) = N_Parameter_Association then
3784 Check_Identifier (Selector_Name (Parent (A)), F);
3785 end if;
3786 end if;
3787
3788 -- If the formal is Out or In_Out, do not resolve and expand the
3789 -- conversion, because it is subsequently expanded into explicit
3790 -- temporaries and assignments. However, the object of the
3791 -- conversion can be resolved. An exception is the case of tagged
3792 -- type conversion with a class-wide actual. In that case we want
3793 -- the tag check to occur and no temporary will be needed (no
3794 -- representation change can occur) and the parameter is passed by
3795 -- reference, so we go ahead and resolve the type conversion.
3796 -- Another exception is the case of reference to component or
3797 -- subcomponent of a bit-packed array, in which case we want to
3798 -- defer expansion to the point the in and out assignments are
3799 -- performed.
3800
3801 if Ekind (F) /= E_In_Parameter
3802 and then Nkind (A) = N_Type_Conversion
3803 and then not Is_Class_Wide_Type (Etype (Expression (A)))
3804 then
3805 if Ekind (F) = E_In_Out_Parameter
3806 and then Is_Array_Type (Etype (F))
3807 then
3808 -- In a view conversion, the conversion must be legal in
3809 -- both directions, and thus both component types must be
3810 -- aliased, or neither (4.6 (8)).
3811
3812 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3813 -- the privacy requirement should not apply to generic
3814 -- types, and should be checked in an instance. ARG query
3815 -- is in order ???
3816
3817 if Has_Aliased_Components (Etype (Expression (A))) /=
3818 Has_Aliased_Components (Etype (F))
3819 then
3820 Error_Msg_N
3821 ("both component types in a view conversion must be"
3822 & " aliased, or neither", A);
3823
3824 -- Comment here??? what set of cases???
3825
3826 elsif
3827 not Same_Ancestor (Etype (F), Etype (Expression (A)))
3828 then
3829 -- Check view conv between unrelated by ref array types
3830
3831 if Is_By_Reference_Type (Etype (F))
3832 or else Is_By_Reference_Type (Etype (Expression (A)))
3833 then
3834 Error_Msg_N
3835 ("view conversion between unrelated by reference "
3836 & "array types not allowed (\'A'I-00246)", A);
3837
3838 -- In Ada 2005 mode, check view conversion component
3839 -- type cannot be private, tagged, or volatile. Note
3840 -- that we only apply this to source conversions. The
3841 -- generated code can contain conversions which are
3842 -- not subject to this test, and we cannot extract the
3843 -- component type in such cases since it is not present.
3844
3845 elsif Comes_From_Source (A)
3846 and then Ada_Version >= Ada_2005
3847 then
3848 declare
3849 Comp_Type : constant Entity_Id :=
3850 Component_Type
3851 (Etype (Expression (A)));
3852 begin
3853 if (Is_Private_Type (Comp_Type)
3854 and then not Is_Generic_Type (Comp_Type))
3855 or else Is_Tagged_Type (Comp_Type)
3856 or else Is_Volatile (Comp_Type)
3857 then
3858 Error_Msg_N
3859 ("component type of a view conversion cannot"
3860 & " be private, tagged, or volatile"
3861 & " (RM 4.6 (24))",
3862 Expression (A));
3863 end if;
3864 end;
3865 end if;
3866 end if;
3867 end if;
3868
3869 -- Resolve expression if conversion is all OK
3870
3871 if (Conversion_OK (A)
3872 or else Valid_Conversion (A, Etype (A), Expression (A)))
3873 and then not Is_Ref_To_Bit_Packed_Array (Expression (A))
3874 then
3875 Resolve (Expression (A));
3876 end if;
3877
3878 -- If the actual is a function call that returns a limited
3879 -- unconstrained object that needs finalization, create a
3880 -- transient scope for it, so that it can receive the proper
3881 -- finalization list.
3882
3883 elsif Nkind (A) = N_Function_Call
3884 and then Is_Limited_Record (Etype (F))
3885 and then not Is_Constrained (Etype (F))
3886 and then Expander_Active
3887 and then (Is_Controlled (Etype (F)) or else Has_Task (Etype (F)))
3888 then
3889 Establish_Transient_Scope (A, Sec_Stack => False);
3890 Resolve (A, Etype (F));
3891
3892 -- A small optimization: if one of the actuals is a concatenation
3893 -- create a block around a procedure call to recover stack space.
3894 -- This alleviates stack usage when several procedure calls in
3895 -- the same statement list use concatenation. We do not perform
3896 -- this wrapping for code statements, where the argument is a
3897 -- static string, and we want to preserve warnings involving
3898 -- sequences of such statements.
3899
3900 elsif Nkind (A) = N_Op_Concat
3901 and then Nkind (N) = N_Procedure_Call_Statement
3902 and then Expander_Active
3903 and then
3904 not (Is_Intrinsic_Subprogram (Nam)
3905 and then Chars (Nam) = Name_Asm)
3906 and then not Static_Concatenation (A)
3907 then
3908 Establish_Transient_Scope (A, Sec_Stack => False);
3909 Resolve (A, Etype (F));
3910
3911 else
3912 if Nkind (A) = N_Type_Conversion
3913 and then Is_Array_Type (Etype (F))
3914 and then not Same_Ancestor (Etype (F), Etype (Expression (A)))
3915 and then
3916 (Is_Limited_Type (Etype (F))
3917 or else Is_Limited_Type (Etype (Expression (A))))
3918 then
3919 Error_Msg_N
3920 ("conversion between unrelated limited array types "
3921 & "not allowed ('A'I-00246)", A);
3922
3923 if Is_Limited_Type (Etype (F)) then
3924 Explain_Limited_Type (Etype (F), A);
3925 end if;
3926
3927 if Is_Limited_Type (Etype (Expression (A))) then
3928 Explain_Limited_Type (Etype (Expression (A)), A);
3929 end if;
3930 end if;
3931
3932 -- (Ada 2005: AI-251): If the actual is an allocator whose
3933 -- directly designated type is a class-wide interface, we build
3934 -- an anonymous access type to use it as the type of the
3935 -- allocator. Later, when the subprogram call is expanded, if
3936 -- the interface has a secondary dispatch table the expander
3937 -- will add a type conversion to force the correct displacement
3938 -- of the pointer.
3939
3940 if Nkind (A) = N_Allocator then
3941 declare
3942 DDT : constant Entity_Id :=
3943 Directly_Designated_Type (Base_Type (Etype (F)));
3944
3945 New_Itype : Entity_Id;
3946
3947 begin
3948 if Is_Class_Wide_Type (DDT)
3949 and then Is_Interface (DDT)
3950 then
3951 New_Itype := Create_Itype (E_Anonymous_Access_Type, A);
3952 Set_Etype (New_Itype, Etype (A));
3953 Set_Directly_Designated_Type
3954 (New_Itype, Directly_Designated_Type (Etype (A)));
3955 Set_Etype (A, New_Itype);
3956 end if;
3957
3958 -- Ada 2005, AI-162:If the actual is an allocator, the
3959 -- innermost enclosing statement is the master of the
3960 -- created object. This needs to be done with expansion
3961 -- enabled only, otherwise the transient scope will not
3962 -- be removed in the expansion of the wrapped construct.
3963
3964 if (Is_Controlled (DDT) or else Has_Task (DDT))
3965 and then Expander_Active
3966 then
3967 Establish_Transient_Scope (A, Sec_Stack => False);
3968 end if;
3969 end;
3970
3971 if Ekind (Etype (F)) = E_Anonymous_Access_Type then
3972 Check_Restriction (No_Access_Parameter_Allocators, A);
3973 end if;
3974 end if;
3975
3976 -- (Ada 2005): The call may be to a primitive operation of a
3977 -- tagged synchronized type, declared outside of the type. In
3978 -- this case the controlling actual must be converted to its
3979 -- corresponding record type, which is the formal type. The
3980 -- actual may be a subtype, either because of a constraint or
3981 -- because it is a generic actual, so use base type to locate
3982 -- concurrent type.
3983
3984 F_Typ := Base_Type (Etype (F));
3985
3986 if Is_Tagged_Type (F_Typ)
3987 and then (Is_Concurrent_Type (F_Typ)
3988 or else Is_Concurrent_Record_Type (F_Typ))
3989 then
3990 -- If the actual is overloaded, look for an interpretation
3991 -- that has a synchronized type.
3992
3993 if not Is_Overloaded (A) then
3994 A_Typ := Base_Type (Etype (A));
3995
3996 else
3997 declare
3998 Index : Interp_Index;
3999 It : Interp;
4000
4001 begin
4002 Get_First_Interp (A, Index, It);
4003 while Present (It.Typ) loop
4004 if Is_Concurrent_Type (It.Typ)
4005 or else Is_Concurrent_Record_Type (It.Typ)
4006 then
4007 A_Typ := Base_Type (It.Typ);
4008 exit;
4009 end if;
4010
4011 Get_Next_Interp (Index, It);
4012 end loop;
4013 end;
4014 end if;
4015
4016 declare
4017 Full_A_Typ : Entity_Id;
4018
4019 begin
4020 if Present (Full_View (A_Typ)) then
4021 Full_A_Typ := Base_Type (Full_View (A_Typ));
4022 else
4023 Full_A_Typ := A_Typ;
4024 end if;
4025
4026 -- Tagged synchronized type (case 1): the actual is a
4027 -- concurrent type.
4028
4029 if Is_Concurrent_Type (A_Typ)
4030 and then Corresponding_Record_Type (A_Typ) = F_Typ
4031 then
4032 Rewrite (A,
4033 Unchecked_Convert_To
4034 (Corresponding_Record_Type (A_Typ), A));
4035 Resolve (A, Etype (F));
4036
4037 -- Tagged synchronized type (case 2): the formal is a
4038 -- concurrent type.
4039
4040 elsif Ekind (Full_A_Typ) = E_Record_Type
4041 and then Present
4042 (Corresponding_Concurrent_Type (Full_A_Typ))
4043 and then Is_Concurrent_Type (F_Typ)
4044 and then Present (Corresponding_Record_Type (F_Typ))
4045 and then Full_A_Typ = Corresponding_Record_Type (F_Typ)
4046 then
4047 Resolve (A, Corresponding_Record_Type (F_Typ));
4048
4049 -- Common case
4050
4051 else
4052 Resolve (A, Etype (F));
4053 end if;
4054 end;
4055
4056 -- Not a synchronized operation
4057
4058 else
4059 Resolve (A, Etype (F));
4060 end if;
4061 end if;
4062
4063 A_Typ := Etype (A);
4064 F_Typ := Etype (F);
4065
4066 -- An actual cannot be an untagged formal incomplete type
4067
4068 if Ekind (A_Typ) = E_Incomplete_Type
4069 and then not Is_Tagged_Type (A_Typ)
4070 and then Is_Generic_Type (A_Typ)
4071 then
4072 Error_Msg_N
4073 ("invalid use of untagged formal incomplete type", A);
4074 end if;
4075
4076 if Comes_From_Source (Original_Node (N))
4077 and then Nkind_In (Original_Node (N), N_Function_Call,
4078 N_Procedure_Call_Statement)
4079 then
4080 -- In formal mode, check that actual parameters matching
4081 -- formals of tagged types are objects (or ancestor type
4082 -- conversions of objects), not general expressions.
4083
4084 if Is_Actual_Tagged_Parameter (A) then
4085 if Is_SPARK_05_Object_Reference (A) then
4086 null;
4087
4088 elsif Nkind (A) = N_Type_Conversion then
4089 declare
4090 Operand : constant Node_Id := Expression (A);
4091 Operand_Typ : constant Entity_Id := Etype (Operand);
4092 Target_Typ : constant Entity_Id := A_Typ;
4093
4094 begin
4095 if not Is_SPARK_05_Object_Reference (Operand) then
4096 Check_SPARK_05_Restriction
4097 ("object required", Operand);
4098
4099 -- In formal mode, the only view conversions are those
4100 -- involving ancestor conversion of an extended type.
4101
4102 elsif not
4103 (Is_Tagged_Type (Target_Typ)
4104 and then not Is_Class_Wide_Type (Target_Typ)
4105 and then Is_Tagged_Type (Operand_Typ)
4106 and then not Is_Class_Wide_Type (Operand_Typ)
4107 and then Is_Ancestor (Target_Typ, Operand_Typ))
4108 then
4109 if Ekind_In
4110 (F, E_Out_Parameter, E_In_Out_Parameter)
4111 then
4112 Check_SPARK_05_Restriction
4113 ("ancestor conversion is the only permitted "
4114 & "view conversion", A);
4115 else
4116 Check_SPARK_05_Restriction
4117 ("ancestor conversion required", A);
4118 end if;
4119
4120 else
4121 null;
4122 end if;
4123 end;
4124
4125 else
4126 Check_SPARK_05_Restriction ("object required", A);
4127 end if;
4128
4129 -- In formal mode, the only view conversions are those
4130 -- involving ancestor conversion of an extended type.
4131
4132 elsif Nkind (A) = N_Type_Conversion
4133 and then Ekind_In (F, E_Out_Parameter, E_In_Out_Parameter)
4134 then
4135 Check_SPARK_05_Restriction
4136 ("ancestor conversion is the only permitted view "
4137 & "conversion", A);
4138 end if;
4139 end if;
4140
4141 -- has warnings suppressed, then we reset Never_Set_In_Source for
4142 -- the calling entity. The reason for this is to catch cases like
4143 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4144 -- uses trickery to modify an IN parameter.
4145
4146 if Ekind (F) = E_In_Parameter
4147 and then Is_Entity_Name (A)
4148 and then Present (Entity (A))
4149 and then Ekind (Entity (A)) = E_Variable
4150 and then Has_Warnings_Off (F_Typ)
4151 then
4152 Set_Never_Set_In_Source (Entity (A), False);
4153 end if;
4154
4155 -- Perform error checks for IN and IN OUT parameters
4156
4157 if Ekind (F) /= E_Out_Parameter then
4158
4159 -- Check unset reference. For scalar parameters, it is clearly
4160 -- wrong to pass an uninitialized value as either an IN or
4161 -- IN-OUT parameter. For composites, it is also clearly an
4162 -- error to pass a completely uninitialized value as an IN
4163 -- parameter, but the case of IN OUT is trickier. We prefer
4164 -- not to give a warning here. For example, suppose there is
4165 -- a routine that sets some component of a record to False.
4166 -- It is perfectly reasonable to make this IN-OUT and allow
4167 -- either initialized or uninitialized records to be passed
4168 -- in this case.
4169
4170 -- For partially initialized composite values, we also avoid
4171 -- warnings, since it is quite likely that we are passing a
4172 -- partially initialized value and only the initialized fields
4173 -- will in fact be read in the subprogram.
4174
4175 if Is_Scalar_Type (A_Typ)
4176 or else (Ekind (F) = E_In_Parameter
4177 and then not Is_Partially_Initialized_Type (A_Typ))
4178 then
4179 Check_Unset_Reference (A);
4180 end if;
4181
4182 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4183 -- actual to a nested call, since this constitutes a reading of
4184 -- the parameter, which is not allowed.
4185
4186 if Ada_Version = Ada_83
4187 and then Is_Entity_Name (A)
4188 and then Ekind (Entity (A)) = E_Out_Parameter
4189 then
4190 Error_Msg_N ("(Ada 83) illegal reading of out parameter", A);
4191 end if;
4192 end if;
4193
4194 -- Case of OUT or IN OUT parameter
4195
4196 if Ekind (F) /= E_In_Parameter then
4197
4198 -- For an Out parameter, check for useless assignment. Note
4199 -- that we can't set Last_Assignment this early, because we may
4200 -- kill current values in Resolve_Call, and that call would
4201 -- clobber the Last_Assignment field.
4202
4203 -- Note: call Warn_On_Useless_Assignment before doing the check
4204 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4205 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4206 -- reflects the last assignment, not this one.
4207
4208 if Ekind (F) = E_Out_Parameter then
4209 if Warn_On_Modified_As_Out_Parameter (F)
4210 and then Is_Entity_Name (A)
4211 and then Present (Entity (A))
4212 and then Comes_From_Source (N)
4213 then
4214 Warn_On_Useless_Assignment (Entity (A), A);
4215 end if;
4216 end if;
4217
4218 -- Validate the form of the actual. Note that the call to
4219 -- Is_OK_Variable_For_Out_Formal generates the required
4220 -- reference in this case.
4221
4222 -- A call to an initialization procedure for an aggregate
4223 -- component may initialize a nested component of a constant
4224 -- designated object. In this context the object is variable.
4225
4226 if not Is_OK_Variable_For_Out_Formal (A)
4227 and then not Is_Init_Proc (Nam)
4228 then
4229 Error_Msg_NE ("actual for& must be a variable", A, F);
4230
4231 if Is_Subprogram (Current_Scope) then
4232 if Is_Invariant_Procedure (Current_Scope)
4233 or else Is_Partial_Invariant_Procedure (Current_Scope)
4234 then
4235 Error_Msg_N
4236 ("function used in invariant cannot modify its "
4237 & "argument", F);
4238
4239 elsif Is_Predicate_Function (Current_Scope) then
4240 Error_Msg_N
4241 ("function used in predicate cannot modify its "
4242 & "argument", F);
4243 end if;
4244 end if;
4245 end if;
4246
4247 -- What's the following about???
4248
4249 if Is_Entity_Name (A) then
4250 Kill_Checks (Entity (A));
4251 else
4252 Kill_All_Checks;
4253 end if;
4254 end if;
4255
4256 if Etype (A) = Any_Type then
4257 Set_Etype (N, Any_Type);
4258 return;
4259 end if;
4260
4261 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4262
4263 if Ekind_In (F, E_In_Parameter, E_In_Out_Parameter) then
4264
4265 -- Apply predicate tests except in certain special cases. Note
4266 -- that it might be more consistent to apply these only when
4267 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4268 -- for the outbound predicate tests ???
4269
4270 if Predicate_Tests_On_Arguments (Nam) then
4271 Apply_Predicate_Check (A, F_Typ);
4272 end if;
4273
4274 -- Apply required constraint checks
4275
4276 -- Gigi looks at the check flag and uses the appropriate types.
4277 -- For now since one flag is used there is an optimization
4278 -- which might not be done in the IN OUT case since Gigi does
4279 -- not do any analysis. More thought required about this ???
4280
4281 -- In fact is this comment obsolete??? doesn't the expander now
4282 -- generate all these tests anyway???
4283
4284 if Is_Scalar_Type (Etype (A)) then
4285 Apply_Scalar_Range_Check (A, F_Typ);
4286
4287 elsif Is_Array_Type (Etype (A)) then
4288 Apply_Length_Check (A, F_Typ);
4289
4290 elsif Is_Record_Type (F_Typ)
4291 and then Has_Discriminants (F_Typ)
4292 and then Is_Constrained (F_Typ)
4293 and then (not Is_Derived_Type (F_Typ)
4294 or else Comes_From_Source (Nam))
4295 then
4296 Apply_Discriminant_Check (A, F_Typ);
4297
4298 -- For view conversions of a discriminated object, apply
4299 -- check to object itself, the conversion alreay has the
4300 -- proper type.
4301
4302 if Nkind (A) = N_Type_Conversion
4303 and then Is_Constrained (Etype (Expression (A)))
4304 then
4305 Apply_Discriminant_Check (Expression (A), F_Typ);
4306 end if;
4307
4308 elsif Is_Access_Type (F_Typ)
4309 and then Is_Array_Type (Designated_Type (F_Typ))
4310 and then Is_Constrained (Designated_Type (F_Typ))
4311 then
4312 Apply_Length_Check (A, F_Typ);
4313
4314 elsif Is_Access_Type (F_Typ)
4315 and then Has_Discriminants (Designated_Type (F_Typ))
4316 and then Is_Constrained (Designated_Type (F_Typ))
4317 then
4318 Apply_Discriminant_Check (A, F_Typ);
4319
4320 else
4321 Apply_Range_Check (A, F_Typ);
4322 end if;
4323
4324 -- Ada 2005 (AI-231): Note that the controlling parameter case
4325 -- already existed in Ada 95, which is partially checked
4326 -- elsewhere (see Checks), and we don't want the warning
4327 -- message to differ.
4328
4329 if Is_Access_Type (F_Typ)
4330 and then Can_Never_Be_Null (F_Typ)
4331 and then Known_Null (A)
4332 then
4333 if Is_Controlling_Formal (F) then
4334 Apply_Compile_Time_Constraint_Error
4335 (N => A,
4336 Msg => "null value not allowed here??",
4337 Reason => CE_Access_Check_Failed);
4338
4339 elsif Ada_Version >= Ada_2005 then
4340 Apply_Compile_Time_Constraint_Error
4341 (N => A,
4342 Msg => "(Ada 2005) null not allowed in "
4343 & "null-excluding formal??",
4344 Reason => CE_Null_Not_Allowed);
4345 end if;
4346 end if;
4347 end if;
4348
4349 -- Checks for OUT parameters and IN OUT parameters
4350
4351 if Ekind_In (F, E_Out_Parameter, E_In_Out_Parameter) then
4352
4353 -- If there is a type conversion, to make sure the return value
4354 -- meets the constraints of the variable before the conversion.
4355
4356 if Nkind (A) = N_Type_Conversion then
4357 if Is_Scalar_Type (A_Typ) then
4358 Apply_Scalar_Range_Check
4359 (Expression (A), Etype (Expression (A)), A_Typ);
4360 else
4361 Apply_Range_Check
4362 (Expression (A), Etype (Expression (A)), A_Typ);
4363 end if;
4364
4365 -- If no conversion apply scalar range checks and length checks
4366 -- base on the subtype of the actual (NOT that of the formal).
4367
4368 else
4369 if Is_Scalar_Type (F_Typ) then
4370 Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
4371 elsif Is_Array_Type (F_Typ)
4372 and then Ekind (F) = E_Out_Parameter
4373 then
4374 Apply_Length_Check (A, F_Typ);
4375 else
4376 Apply_Range_Check (A, A_Typ, F_Typ);
4377 end if;
4378 end if;
4379
4380 -- Note: we do not apply the predicate checks for the case of
4381 -- OUT and IN OUT parameters. They are instead applied in the
4382 -- Expand_Actuals routine in Exp_Ch6.
4383 end if;
4384
4385 -- An actual associated with an access parameter is implicitly
4386 -- converted to the anonymous access type of the formal and must
4387 -- satisfy the legality checks for access conversions.
4388
4389 if Ekind (F_Typ) = E_Anonymous_Access_Type then
4390 if not Valid_Conversion (A, F_Typ, A) then
4391 Error_Msg_N
4392 ("invalid implicit conversion for access parameter", A);
4393 end if;
4394
4395 -- If the actual is an access selected component of a variable,
4396 -- the call may modify its designated object. It is reasonable
4397 -- to treat this as a potential modification of the enclosing
4398 -- record, to prevent spurious warnings that it should be
4399 -- declared as a constant, because intuitively programmers
4400 -- regard the designated subcomponent as part of the record.
4401
4402 if Nkind (A) = N_Selected_Component
4403 and then Is_Entity_Name (Prefix (A))
4404 and then not Is_Constant_Object (Entity (Prefix (A)))
4405 then
4406 Note_Possible_Modification (A, Sure => False);
4407 end if;
4408 end if;
4409
4410 -- Check bad case of atomic/volatile argument (RM C.6(12))
4411
4412 if Is_By_Reference_Type (Etype (F))
4413 and then Comes_From_Source (N)
4414 then
4415 if Is_Atomic_Object (A)
4416 and then not Is_Atomic (Etype (F))
4417 then
4418 Error_Msg_NE
4419 ("cannot pass atomic argument to non-atomic formal&",
4420 A, F);
4421
4422 elsif Is_Volatile_Object (A)
4423 and then not Is_Volatile (Etype (F))
4424 then
4425 Error_Msg_NE
4426 ("cannot pass volatile argument to non-volatile formal&",
4427 A, F);
4428 end if;
4429 end if;
4430
4431 -- Check that subprograms don't have improper controlling
4432 -- arguments (RM 3.9.2 (9)).
4433
4434 -- A primitive operation may have an access parameter of an
4435 -- incomplete tagged type, but a dispatching call is illegal
4436 -- if the type is still incomplete.
4437
4438 if Is_Controlling_Formal (F) then
4439 Set_Is_Controlling_Actual (A);
4440
4441 if Ekind (Etype (F)) = E_Anonymous_Access_Type then
4442 declare
4443 Desig : constant Entity_Id := Designated_Type (Etype (F));
4444 begin
4445 if Ekind (Desig) = E_Incomplete_Type
4446 and then No (Full_View (Desig))
4447 and then No (Non_Limited_View (Desig))
4448 then
4449 Error_Msg_NE
4450 ("premature use of incomplete type& "
4451 & "in dispatching call", A, Desig);
4452 end if;
4453 end;
4454 end if;
4455
4456 elsif Nkind (A) = N_Explicit_Dereference then
4457 Validate_Remote_Access_To_Class_Wide_Type (A);
4458 end if;
4459
4460 -- Apply legality rule 3.9.2 (9/1)
4461
4462 if (Is_Class_Wide_Type (A_Typ) or else Is_Dynamically_Tagged (A))
4463 and then not Is_Class_Wide_Type (F_Typ)
4464 and then not Is_Controlling_Formal (F)
4465 and then not In_Instance
4466 then
4467 Error_Msg_N ("class-wide argument not allowed here!", A);
4468
4469 if Is_Subprogram (Nam) and then Comes_From_Source (Nam) then
4470 Error_Msg_Node_2 := F_Typ;
4471 Error_Msg_NE
4472 ("& is not a dispatching operation of &!", A, Nam);
4473 end if;
4474
4475 -- Apply the checks described in 3.10.2(27): if the context is a
4476 -- specific access-to-object, the actual cannot be class-wide.
4477 -- Use base type to exclude access_to_subprogram cases.
4478
4479 elsif Is_Access_Type (A_Typ)
4480 and then Is_Access_Type (F_Typ)
4481 and then not Is_Access_Subprogram_Type (Base_Type (F_Typ))
4482 and then (Is_Class_Wide_Type (Designated_Type (A_Typ))
4483 or else (Nkind (A) = N_Attribute_Reference
4484 and then
4485 Is_Class_Wide_Type (Etype (Prefix (A)))))
4486 and then not Is_Class_Wide_Type (Designated_Type (F_Typ))
4487 and then not Is_Controlling_Formal (F)
4488
4489 -- Disable these checks for call to imported C++ subprograms
4490
4491 and then not
4492 (Is_Entity_Name (Name (N))
4493 and then Is_Imported (Entity (Name (N)))
4494 and then Convention (Entity (Name (N))) = Convention_CPP)
4495 then
4496 Error_Msg_N
4497 ("access to class-wide argument not allowed here!", A);
4498
4499 if Is_Subprogram (Nam) and then Comes_From_Source (Nam) then
4500 Error_Msg_Node_2 := Designated_Type (F_Typ);
4501 Error_Msg_NE
4502 ("& is not a dispatching operation of &!", A, Nam);
4503 end if;
4504 end if;
4505
4506 Check_Aliased_Parameter;
4507
4508 Eval_Actual (A);
4509
4510 -- If it is a named association, treat the selector_name as a
4511 -- proper identifier, and mark the corresponding entity.
4512
4513 if Nkind (Parent (A)) = N_Parameter_Association
4514
4515 -- Ignore reference in SPARK mode, as it refers to an entity not
4516 -- in scope at the point of reference, so the reference should
4517 -- be ignored for computing effects of subprograms.
4518
4519 and then not GNATprove_Mode
4520 then
4521 -- If subprogram is overridden, use name of formal that
4522 -- is being called.
4523
4524 if Present (Real_Subp) then
4525 Set_Entity (Selector_Name (Parent (A)), Real_F);
4526 Set_Etype (Selector_Name (Parent (A)), Etype (Real_F));
4527
4528 else
4529 Set_Entity (Selector_Name (Parent (A)), F);
4530 Generate_Reference (F, Selector_Name (Parent (A)));
4531 Set_Etype (Selector_Name (Parent (A)), F_Typ);
4532 Generate_Reference (F_Typ, N, ' ');
4533 end if;
4534 end if;
4535
4536 Prev := A;
4537
4538 if Ekind (F) /= E_Out_Parameter then
4539 Check_Unset_Reference (A);
4540 end if;
4541
4542 -- The following checks are only relevant when SPARK_Mode is on as
4543 -- they are not standard Ada legality rule. Internally generated
4544 -- temporaries are ignored.
4545
4546 if SPARK_Mode = On and then Comes_From_Source (A) then
4547
4548 -- An effectively volatile object may act as an actual when the
4549 -- corresponding formal is of a non-scalar effectively volatile
4550 -- type (SPARK RM 7.1.3(11)).
4551
4552 if not Is_Scalar_Type (Etype (F))
4553 and then Is_Effectively_Volatile (Etype (F))
4554 then
4555 null;
4556
4557 -- An effectively volatile object may act as an actual in a
4558 -- call to an instance of Unchecked_Conversion.
4559 -- (SPARK RM 7.1.3(11)).
4560
4561 elsif Is_Unchecked_Conversion_Instance (Nam) then
4562 null;
4563
4564 -- The actual denotes an object
4565
4566 elsif Is_Effectively_Volatile_Object (A) then
4567 Error_Msg_N
4568 ("volatile object cannot act as actual in a call (SPARK "
4569 & "RM 7.1.3(11))", A);
4570
4571 -- Otherwise the actual denotes an expression. Inspect the
4572 -- expression and flag each effectively volatile object with
4573 -- enabled property Async_Writers or Effective_Reads as illegal
4574 -- because it apprears within an interfering context. Note that
4575 -- this is usually done in Resolve_Entity_Name, but when the
4576 -- effectively volatile object appears as an actual in a call,
4577 -- the call must be resolved first.
4578
4579 else
4580 Flag_Effectively_Volatile_Objects (A);
4581 end if;
4582
4583 -- Detect an external variable with an enabled property that
4584 -- does not match the mode of the corresponding formal in a
4585 -- procedure call. Functions are not considered because they
4586 -- cannot have effectively volatile formal parameters in the
4587 -- first place.
4588
4589 if Ekind (Nam) = E_Procedure
4590 and then Ekind (F) = E_In_Parameter
4591 and then Is_Entity_Name (A)
4592 and then Present (Entity (A))
4593 and then Ekind (Entity (A)) = E_Variable
4594 then
4595 A_Id := Entity (A);
4596
4597 if Async_Readers_Enabled (A_Id) then
4598 Property_Error (A, A_Id, Name_Async_Readers);
4599 elsif Effective_Reads_Enabled (A_Id) then
4600 Property_Error (A, A_Id, Name_Effective_Reads);
4601 elsif Effective_Writes_Enabled (A_Id) then
4602 Property_Error (A, A_Id, Name_Effective_Writes);
4603 end if;
4604 end if;
4605 end if;
4606
4607 -- A formal parameter of a specific tagged type whose related
4608 -- subprogram is subject to pragma Extensions_Visible with value
4609 -- "False" cannot act as an actual in a subprogram with value
4610 -- "True" (SPARK RM 6.1.7(3)).
4611
4612 if Is_EVF_Expression (A)
4613 and then Extensions_Visible_Status (Nam) =
4614 Extensions_Visible_True
4615 then
4616 Error_Msg_N
4617 ("formal parameter cannot act as actual parameter when "
4618 & "Extensions_Visible is False", A);
4619 Error_Msg_NE
4620 ("\subprogram & has Extensions_Visible True", A, Nam);
4621 end if;
4622
4623 -- The actual parameter of a Ghost subprogram whose formal is of
4624 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4625
4626 if Comes_From_Source (Nam)
4627 and then Is_Ghost_Entity (Nam)
4628 and then Ekind_In (F, E_In_Out_Parameter, E_Out_Parameter)
4629 and then Is_Entity_Name (A)
4630 and then Present (Entity (A))
4631 and then not Is_Ghost_Entity (Entity (A))
4632 then
4633 Error_Msg_NE
4634 ("non-ghost variable & cannot appear as actual in call to "
4635 & "ghost procedure", A, Entity (A));
4636
4637 if Ekind (F) = E_In_Out_Parameter then
4638 Error_Msg_N ("\corresponding formal has mode `IN OUT`", A);
4639 else
4640 Error_Msg_N ("\corresponding formal has mode OUT", A);
4641 end if;
4642 end if;
4643
4644 Next_Actual (A);
4645
4646 -- Case where actual is not present
4647
4648 else
4649 Insert_Default;
4650 end if;
4651
4652 Next_Formal (F);
4653
4654 if Present (Real_Subp) then
4655 Next_Formal (Real_F);
4656 end if;
4657 end loop;
4658 end Resolve_Actuals;
4659
4660 -----------------------
4661 -- Resolve_Allocator --
4662 -----------------------
4663
4664 procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id) is
4665 Desig_T : constant Entity_Id := Designated_Type (Typ);
4666 E : constant Node_Id := Expression (N);
4667 Subtyp : Entity_Id;
4668 Discrim : Entity_Id;
4669 Constr : Node_Id;
4670 Aggr : Node_Id;
4671 Assoc : Node_Id := Empty;
4672 Disc_Exp : Node_Id;
4673
4674 procedure Check_Allocator_Discrim_Accessibility
4675 (Disc_Exp : Node_Id;
4676 Alloc_Typ : Entity_Id);
4677 -- Check that accessibility level associated with an access discriminant
4678 -- initialized in an allocator by the expression Disc_Exp is not deeper
4679 -- than the level of the allocator type Alloc_Typ. An error message is
4680 -- issued if this condition is violated. Specialized checks are done for
4681 -- the cases of a constraint expression which is an access attribute or
4682 -- an access discriminant.
4683
4684 function In_Dispatching_Context return Boolean;
4685 -- If the allocator is an actual in a call, it is allowed to be class-
4686 -- wide when the context is not because it is a controlling actual.
4687
4688 -------------------------------------------
4689 -- Check_Allocator_Discrim_Accessibility --
4690 -------------------------------------------
4691
4692 procedure Check_Allocator_Discrim_Accessibility
4693 (Disc_Exp : Node_Id;
4694 Alloc_Typ : Entity_Id)
4695 is
4696 begin
4697 if Type_Access_Level (Etype (Disc_Exp)) >
4698 Deepest_Type_Access_Level (Alloc_Typ)
4699 then
4700 Error_Msg_N
4701 ("operand type has deeper level than allocator type", Disc_Exp);
4702
4703 -- When the expression is an Access attribute the level of the prefix
4704 -- object must not be deeper than that of the allocator's type.
4705
4706 elsif Nkind (Disc_Exp) = N_Attribute_Reference
4707 and then Get_Attribute_Id (Attribute_Name (Disc_Exp)) =
4708 Attribute_Access
4709 and then Object_Access_Level (Prefix (Disc_Exp)) >
4710 Deepest_Type_Access_Level (Alloc_Typ)
4711 then
4712 Error_Msg_N
4713 ("prefix of attribute has deeper level than allocator type",
4714 Disc_Exp);
4715
4716 -- When the expression is an access discriminant the check is against
4717 -- the level of the prefix object.
4718
4719 elsif Ekind (Etype (Disc_Exp)) = E_Anonymous_Access_Type
4720 and then Nkind (Disc_Exp) = N_Selected_Component
4721 and then Object_Access_Level (Prefix (Disc_Exp)) >
4722 Deepest_Type_Access_Level (Alloc_Typ)
4723 then
4724 Error_Msg_N
4725 ("access discriminant has deeper level than allocator type",
4726 Disc_Exp);
4727
4728 -- All other cases are legal
4729
4730 else
4731 null;
4732 end if;
4733 end Check_Allocator_Discrim_Accessibility;
4734
4735 ----------------------------
4736 -- In_Dispatching_Context --
4737 ----------------------------
4738
4739 function In_Dispatching_Context return Boolean is
4740 Par : constant Node_Id := Parent (N);
4741
4742 begin
4743 return Nkind (Par) in N_Subprogram_Call
4744 and then Is_Entity_Name (Name (Par))
4745 and then Is_Dispatching_Operation (Entity (Name (Par)));
4746 end In_Dispatching_Context;
4747
4748 -- Start of processing for Resolve_Allocator
4749
4750 begin
4751 -- Replace general access with specific type
4752
4753 if Ekind (Etype (N)) = E_Allocator_Type then
4754 Set_Etype (N, Base_Type (Typ));
4755 end if;
4756
4757 if Is_Abstract_Type (Typ) then
4758 Error_Msg_N ("type of allocator cannot be abstract", N);
4759 end if;
4760
4761 -- For qualified expression, resolve the expression using the given
4762 -- subtype (nothing to do for type mark, subtype indication)
4763
4764 if Nkind (E) = N_Qualified_Expression then
4765 if Is_Class_Wide_Type (Etype (E))
4766 and then not Is_Class_Wide_Type (Desig_T)
4767 and then not In_Dispatching_Context
4768 then
4769 Error_Msg_N
4770 ("class-wide allocator not allowed for this access type", N);
4771 end if;
4772
4773 Resolve (Expression (E), Etype (E));
4774 Check_Non_Static_Context (Expression (E));
4775 Check_Unset_Reference (Expression (E));
4776
4777 -- Allocators generated by the build-in-place expansion mechanism
4778 -- are explicitly marked as coming from source but do not need to be
4779 -- checked for limited initialization. To exclude this case, ensure
4780 -- that the parent of the allocator is a source node.
4781
4782 if Is_Limited_Type (Etype (E))
4783 and then Comes_From_Source (N)
4784 and then Comes_From_Source (Parent (N))
4785 and then not In_Instance_Body
4786 then
4787 if not OK_For_Limited_Init (Etype (E), Expression (E)) then
4788 if Nkind (Parent (N)) = N_Assignment_Statement then
4789 Error_Msg_N
4790 ("illegal expression for initialized allocator of a "
4791 & "limited type (RM 7.5 (2.7/2))", N);
4792 else
4793 Error_Msg_N
4794 ("initialization not allowed for limited types", N);
4795 end if;
4796
4797 Explain_Limited_Type (Etype (E), N);
4798 end if;
4799 end if;
4800
4801 -- A qualified expression requires an exact match of the type. Class-
4802 -- wide matching is not allowed.
4803
4804 if (Is_Class_Wide_Type (Etype (Expression (E)))
4805 or else Is_Class_Wide_Type (Etype (E)))
4806 and then Base_Type (Etype (Expression (E))) /= Base_Type (Etype (E))
4807 then
4808 Wrong_Type (Expression (E), Etype (E));
4809 end if;
4810
4811 -- Calls to build-in-place functions are not currently supported in
4812 -- allocators for access types associated with a simple storage pool.
4813 -- Supporting such allocators may require passing additional implicit
4814 -- parameters to build-in-place functions (or a significant revision
4815 -- of the current b-i-p implementation to unify the handling for
4816 -- multiple kinds of storage pools). ???
4817
4818 if Is_Limited_View (Desig_T)
4819 and then Nkind (Expression (E)) = N_Function_Call
4820 then
4821 declare
4822 Pool : constant Entity_Id :=
4823 Associated_Storage_Pool (Root_Type (Typ));
4824 begin
4825 if Present (Pool)
4826 and then
4827 Present (Get_Rep_Pragma
4828 (Etype (Pool), Name_Simple_Storage_Pool_Type))
4829 then
4830 Error_Msg_N
4831 ("limited function calls not yet supported in simple "
4832 & "storage pool allocators", Expression (E));
4833 end if;
4834 end;
4835 end if;
4836
4837 -- A special accessibility check is needed for allocators that
4838 -- constrain access discriminants. The level of the type of the
4839 -- expression used to constrain an access discriminant cannot be
4840 -- deeper than the type of the allocator (in contrast to access
4841 -- parameters, where the level of the actual can be arbitrary).
4842
4843 -- We can't use Valid_Conversion to perform this check because in
4844 -- general the type of the allocator is unrelated to the type of
4845 -- the access discriminant.
4846
4847 if Ekind (Typ) /= E_Anonymous_Access_Type
4848 or else Is_Local_Anonymous_Access (Typ)
4849 then
4850 Subtyp := Entity (Subtype_Mark (E));
4851
4852 Aggr := Original_Node (Expression (E));
4853
4854 if Has_Discriminants (Subtyp)
4855 and then Nkind_In (Aggr, N_Aggregate, N_Extension_Aggregate)
4856 then
4857 Discrim := First_Discriminant (Base_Type (Subtyp));
4858
4859 -- Get the first component expression of the aggregate
4860
4861 if Present (Expressions (Aggr)) then
4862 Disc_Exp := First (Expressions (Aggr));
4863
4864 elsif Present (Component_Associations (Aggr)) then
4865 Assoc := First (Component_Associations (Aggr));
4866
4867 if Present (Assoc) then
4868 Disc_Exp := Expression (Assoc);
4869 else
4870 Disc_Exp := Empty;
4871 end if;
4872
4873 else
4874 Disc_Exp := Empty;
4875 end if;
4876
4877 while Present (Discrim) and then Present (Disc_Exp) loop
4878 if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
4879 Check_Allocator_Discrim_Accessibility (Disc_Exp, Typ);
4880 end if;
4881
4882 Next_Discriminant (Discrim);
4883
4884 if Present (Discrim) then
4885 if Present (Assoc) then
4886 Next (Assoc);
4887 Disc_Exp := Expression (Assoc);
4888
4889 elsif Present (Next (Disc_Exp)) then
4890 Next (Disc_Exp);
4891
4892 else
4893 Assoc := First (Component_Associations (Aggr));
4894
4895 if Present (Assoc) then
4896 Disc_Exp := Expression (Assoc);
4897 else
4898 Disc_Exp := Empty;
4899 end if;
4900 end if;
4901 end if;
4902 end loop;
4903 end if;
4904 end if;
4905
4906 -- For a subtype mark or subtype indication, freeze the subtype
4907
4908 else
4909 Freeze_Expression (E);
4910
4911 if Is_Access_Constant (Typ) and then not No_Initialization (N) then
4912 Error_Msg_N
4913 ("initialization required for access-to-constant allocator", N);
4914 end if;
4915
4916 -- A special accessibility check is needed for allocators that
4917 -- constrain access discriminants. The level of the type of the
4918 -- expression used to constrain an access discriminant cannot be
4919 -- deeper than the type of the allocator (in contrast to access
4920 -- parameters, where the level of the actual can be arbitrary).
4921 -- We can't use Valid_Conversion to perform this check because
4922 -- in general the type of the allocator is unrelated to the type
4923 -- of the access discriminant.
4924
4925 if Nkind (Original_Node (E)) = N_Subtype_Indication
4926 and then (Ekind (Typ) /= E_Anonymous_Access_Type
4927 or else Is_Local_Anonymous_Access (Typ))
4928 then
4929 Subtyp := Entity (Subtype_Mark (Original_Node (E)));
4930
4931 if Has_Discriminants (Subtyp) then
4932 Discrim := First_Discriminant (Base_Type (Subtyp));
4933 Constr := First (Constraints (Constraint (Original_Node (E))));
4934 while Present (Discrim) and then Present (Constr) loop
4935 if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
4936 if Nkind (Constr) = N_Discriminant_Association then
4937 Disc_Exp := Original_Node (Expression (Constr));
4938 else
4939 Disc_Exp := Original_Node (Constr);
4940 end if;
4941
4942 Check_Allocator_Discrim_Accessibility (Disc_Exp, Typ);
4943 end if;
4944
4945 Next_Discriminant (Discrim);
4946 Next (Constr);
4947 end loop;
4948 end if;
4949 end if;
4950 end if;
4951
4952 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4953 -- check that the level of the type of the created object is not deeper
4954 -- than the level of the allocator's access type, since extensions can
4955 -- now occur at deeper levels than their ancestor types. This is a
4956 -- static accessibility level check; a run-time check is also needed in
4957 -- the case of an initialized allocator with a class-wide argument (see
4958 -- Expand_Allocator_Expression).
4959
4960 if Ada_Version >= Ada_2005
4961 and then Is_Class_Wide_Type (Desig_T)
4962 then
4963 declare
4964 Exp_Typ : Entity_Id;
4965
4966 begin
4967 if Nkind (E) = N_Qualified_Expression then
4968 Exp_Typ := Etype (E);
4969 elsif Nkind (E) = N_Subtype_Indication then
4970 Exp_Typ := Entity (Subtype_Mark (Original_Node (E)));
4971 else
4972 Exp_Typ := Entity (E);
4973 end if;
4974
4975 if Type_Access_Level (Exp_Typ) >
4976 Deepest_Type_Access_Level (Typ)
4977 then
4978 if In_Instance_Body then
4979 Error_Msg_Warn := SPARK_Mode /= On;
4980 Error_Msg_N
4981 ("type in allocator has deeper level than "
4982 & "designated class-wide type<<", E);
4983 Error_Msg_N ("\Program_Error [<<", E);
4984 Rewrite (N,
4985 Make_Raise_Program_Error (Sloc (N),
4986 Reason => PE_Accessibility_Check_Failed));
4987 Set_Etype (N, Typ);
4988
4989 -- Do not apply Ada 2005 accessibility checks on a class-wide
4990 -- allocator if the type given in the allocator is a formal
4991 -- type. A run-time check will be performed in the instance.
4992
4993 elsif not Is_Generic_Type (Exp_Typ) then
4994 Error_Msg_N ("type in allocator has deeper level than "
4995 & "designated class-wide type", E);
4996 end if;
4997 end if;
4998 end;
4999 end if;
5000
5001 -- Check for allocation from an empty storage pool
5002
5003 if No_Pool_Assigned (Typ) then
5004 Error_Msg_N ("allocation from empty storage pool!", N);
5005
5006 -- If the context is an unchecked conversion, as may happen within an
5007 -- inlined subprogram, the allocator is being resolved with its own
5008 -- anonymous type. In that case, if the target type has a specific
5009 -- storage pool, it must be inherited explicitly by the allocator type.
5010
5011 elsif Nkind (Parent (N)) = N_Unchecked_Type_Conversion
5012 and then No (Associated_Storage_Pool (Typ))
5013 then
5014 Set_Associated_Storage_Pool
5015 (Typ, Associated_Storage_Pool (Etype (Parent (N))));
5016 end if;
5017
5018 if Ekind (Etype (N)) = E_Anonymous_Access_Type then
5019 Check_Restriction (No_Anonymous_Allocators, N);
5020 end if;
5021
5022 -- Check that an allocator with task parts isn't for a nested access
5023 -- type when restriction No_Task_Hierarchy applies.
5024
5025 if not Is_Library_Level_Entity (Base_Type (Typ))
5026 and then Has_Task (Base_Type (Desig_T))
5027 then
5028 Check_Restriction (No_Task_Hierarchy, N);
5029 end if;
5030
5031 -- An illegal allocator may be rewritten as a raise Program_Error
5032 -- statement.
5033
5034 if Nkind (N) = N_Allocator then
5035
5036 -- An anonymous access discriminant is the definition of a
5037 -- coextension.
5038
5039 if Ekind (Typ) = E_Anonymous_Access_Type
5040 and then Nkind (Associated_Node_For_Itype (Typ)) =
5041 N_Discriminant_Specification
5042 then
5043 declare
5044 Discr : constant Entity_Id :=
5045 Defining_Identifier (Associated_Node_For_Itype (Typ));
5046
5047 begin
5048 Check_Restriction (No_Coextensions, N);
5049
5050 -- Ada 2012 AI05-0052: If the designated type of the allocator
5051 -- is limited, then the allocator shall not be used to define
5052 -- the value of an access discriminant unless the discriminated
5053 -- type is immutably limited.
5054
5055 if Ada_Version >= Ada_2012
5056 and then Is_Limited_Type (Desig_T)
5057 and then not Is_Limited_View (Scope (Discr))
5058 then
5059 Error_Msg_N
5060 ("only immutably limited types can have anonymous "
5061 & "access discriminants designating a limited type", N);
5062 end if;
5063 end;
5064
5065 -- Avoid marking an allocator as a dynamic coextension if it is
5066 -- within a static construct.
5067
5068 if not Is_Static_Coextension (N) then
5069 Set_Is_Dynamic_Coextension (N);
5070 end if;
5071
5072 -- Cleanup for potential static coextensions
5073
5074 else
5075 Set_Is_Dynamic_Coextension (N, False);
5076 Set_Is_Static_Coextension (N, False);
5077 end if;
5078 end if;
5079
5080 -- Report a simple error: if the designated object is a local task,
5081 -- its body has not been seen yet, and its activation will fail an
5082 -- elaboration check.
5083
5084 if Is_Task_Type (Desig_T)
5085 and then Scope (Base_Type (Desig_T)) = Current_Scope
5086 and then Is_Compilation_Unit (Current_Scope)
5087 and then Ekind (Current_Scope) = E_Package
5088 and then not In_Package_Body (Current_Scope)
5089 then
5090 Error_Msg_Warn := SPARK_Mode /= On;
5091 Error_Msg_N ("cannot activate task before body seen<<", N);
5092 Error_Msg_N ("\Program_Error [<<", N);
5093 end if;
5094
5095 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5096 -- type with a task component on a subpool. This action must raise
5097 -- Program_Error at runtime.
5098
5099 if Ada_Version >= Ada_2012
5100 and then Nkind (N) = N_Allocator
5101 and then Present (Subpool_Handle_Name (N))
5102 and then Has_Task (Desig_T)
5103 then
5104 Error_Msg_Warn := SPARK_Mode /= On;
5105 Error_Msg_N ("cannot allocate task on subpool<<", N);
5106 Error_Msg_N ("\Program_Error [<<", N);
5107
5108 Rewrite (N,
5109 Make_Raise_Program_Error (Sloc (N),
5110 Reason => PE_Explicit_Raise));
5111 Set_Etype (N, Typ);
5112 end if;
5113 end Resolve_Allocator;
5114
5115 ---------------------------
5116 -- Resolve_Arithmetic_Op --
5117 ---------------------------
5118
5119 -- Used for resolving all arithmetic operators except exponentiation
5120
5121 procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id) is
5122 L : constant Node_Id := Left_Opnd (N);
5123 R : constant Node_Id := Right_Opnd (N);
5124 TL : constant Entity_Id := Base_Type (Etype (L));
5125 TR : constant Entity_Id := Base_Type (Etype (R));
5126 T : Entity_Id;
5127 Rop : Node_Id;
5128
5129 B_Typ : constant Entity_Id := Base_Type (Typ);
5130 -- We do the resolution using the base type, because intermediate values
5131 -- in expressions always are of the base type, not a subtype of it.
5132
5133 function Expected_Type_Is_Any_Real (N : Node_Id) return Boolean;
5134 -- Returns True if N is in a context that expects "any real type"
5135
5136 function Is_Integer_Or_Universal (N : Node_Id) return Boolean;
5137 -- Return True iff given type is Integer or universal real/integer
5138
5139 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id);
5140 -- Choose type of integer literal in fixed-point operation to conform
5141 -- to available fixed-point type. T is the type of the other operand,
5142 -- which is needed to determine the expected type of N.
5143
5144 procedure Set_Operand_Type (N : Node_Id);
5145 -- Set operand type to T if universal
5146
5147 -------------------------------
5148 -- Expected_Type_Is_Any_Real --
5149 -------------------------------
5150
5151 function Expected_Type_Is_Any_Real (N : Node_Id) return Boolean is
5152 begin
5153 -- N is the expression after "delta" in a fixed_point_definition;
5154 -- see RM-3.5.9(6):
5155
5156 return Nkind_In (Parent (N), N_Ordinary_Fixed_Point_Definition,
5157 N_Decimal_Fixed_Point_Definition,
5158
5159 -- N is one of the bounds in a real_range_specification;
5160 -- see RM-3.5.7(5):
5161
5162 N_Real_Range_Specification,
5163
5164 -- N is the expression of a delta_constraint;
5165 -- see RM-J.3(3):
5166
5167 N_Delta_Constraint);
5168 end Expected_Type_Is_Any_Real;
5169
5170 -----------------------------
5171 -- Is_Integer_Or_Universal --
5172 -----------------------------
5173
5174 function Is_Integer_Or_Universal (N : Node_Id) return Boolean is
5175 T : Entity_Id;
5176 Index : Interp_Index;
5177 It : Interp;
5178
5179 begin
5180 if not Is_Overloaded (N) then
5181 T := Etype (N);
5182 return Base_Type (T) = Base_Type (Standard_Integer)
5183 or else T = Universal_Integer
5184 or else T = Universal_Real;
5185 else
5186 Get_First_Interp (N, Index, It);
5187 while Present (It.Typ) loop
5188 if Base_Type (It.Typ) = Base_Type (Standard_Integer)
5189 or else It.Typ = Universal_Integer
5190 or else It.Typ = Universal_Real
5191 then
5192 return True;
5193 end if;
5194
5195 Get_Next_Interp (Index, It);
5196 end loop;
5197 end if;
5198
5199 return False;
5200 end Is_Integer_Or_Universal;
5201
5202 ----------------------------
5203 -- Set_Mixed_Mode_Operand --
5204 ----------------------------
5205
5206 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id) is
5207 Index : Interp_Index;
5208 It : Interp;
5209
5210 begin
5211 if Universal_Interpretation (N) = Universal_Integer then
5212
5213 -- A universal integer literal is resolved as standard integer
5214 -- except in the case of a fixed-point result, where we leave it
5215 -- as universal (to be handled by Exp_Fixd later on)
5216
5217 if Is_Fixed_Point_Type (T) then
5218 Resolve (N, Universal_Integer);
5219 else
5220 Resolve (N, Standard_Integer);
5221 end if;
5222
5223 elsif Universal_Interpretation (N) = Universal_Real
5224 and then (T = Base_Type (Standard_Integer)
5225 or else T = Universal_Integer
5226 or else T = Universal_Real)
5227 then
5228 -- A universal real can appear in a fixed-type context. We resolve
5229 -- the literal with that context, even though this might raise an
5230 -- exception prematurely (the other operand may be zero).
5231
5232 Resolve (N, B_Typ);
5233
5234 elsif Etype (N) = Base_Type (Standard_Integer)
5235 and then T = Universal_Real
5236 and then Is_Overloaded (N)
5237 then
5238 -- Integer arg in mixed-mode operation. Resolve with universal
5239 -- type, in case preference rule must be applied.
5240
5241 Resolve (N, Universal_Integer);
5242
5243 elsif Etype (N) = T
5244 and then B_Typ /= Universal_Fixed
5245 then
5246 -- Not a mixed-mode operation, resolve with context
5247
5248 Resolve (N, B_Typ);
5249
5250 elsif Etype (N) = Any_Fixed then
5251
5252 -- N may itself be a mixed-mode operation, so use context type
5253
5254 Resolve (N, B_Typ);
5255
5256 elsif Is_Fixed_Point_Type (T)
5257 and then B_Typ = Universal_Fixed
5258 and then Is_Overloaded (N)
5259 then
5260 -- Must be (fixed * fixed) operation, operand must have one
5261 -- compatible interpretation.
5262
5263 Resolve (N, Any_Fixed);
5264
5265 elsif Is_Fixed_Point_Type (B_Typ)
5266 and then (T = Universal_Real or else Is_Fixed_Point_Type (T))
5267 and then Is_Overloaded (N)
5268 then
5269 -- C * F(X) in a fixed context, where C is a real literal or a
5270 -- fixed-point expression. F must have either a fixed type
5271 -- interpretation or an integer interpretation, but not both.
5272
5273 Get_First_Interp (N, Index, It);
5274 while Present (It.Typ) loop
5275 if Base_Type (It.Typ) = Base_Type (Standard_Integer) then
5276 if Analyzed (N) then
5277 Error_Msg_N ("ambiguous operand in fixed operation", N);
5278 else
5279 Resolve (N, Standard_Integer);
5280 end if;
5281
5282 elsif Is_Fixed_Point_Type (It.Typ) then
5283 if Analyzed (N) then
5284 Error_Msg_N ("ambiguous operand in fixed operation", N);
5285 else
5286 Resolve (N, It.Typ);
5287 end if;
5288 end if;
5289
5290 Get_Next_Interp (Index, It);
5291 end loop;
5292
5293 -- Reanalyze the literal with the fixed type of the context. If
5294 -- context is Universal_Fixed, we are within a conversion, leave
5295 -- the literal as a universal real because there is no usable
5296 -- fixed type, and the target of the conversion plays no role in
5297 -- the resolution.
5298
5299 declare
5300 Op2 : Node_Id;
5301 T2 : Entity_Id;
5302
5303 begin
5304 if N = L then
5305 Op2 := R;
5306 else
5307 Op2 := L;
5308 end if;
5309
5310 if B_Typ = Universal_Fixed
5311 and then Nkind (Op2) = N_Real_Literal
5312 then
5313 T2 := Universal_Real;
5314 else
5315 T2 := B_Typ;
5316 end if;
5317
5318 Set_Analyzed (Op2, False);
5319 Resolve (Op2, T2);
5320 end;
5321
5322 else
5323 Resolve (N);
5324 end if;
5325 end Set_Mixed_Mode_Operand;
5326
5327 ----------------------
5328 -- Set_Operand_Type --
5329 ----------------------
5330
5331 procedure Set_Operand_Type (N : Node_Id) is
5332 begin
5333 if Etype (N) = Universal_Integer
5334 or else Etype (N) = Universal_Real
5335 then
5336 Set_Etype (N, T);
5337 end if;
5338 end Set_Operand_Type;
5339
5340 -- Start of processing for Resolve_Arithmetic_Op
5341
5342 begin
5343 if Comes_From_Source (N)
5344 and then Ekind (Entity (N)) = E_Function
5345 and then Is_Imported (Entity (N))
5346 and then Is_Intrinsic_Subprogram (Entity (N))
5347 then
5348 Resolve_Intrinsic_Operator (N, Typ);
5349 return;
5350
5351 -- Special-case for mixed-mode universal expressions or fixed point type
5352 -- operation: each argument is resolved separately. The same treatment
5353 -- is required if one of the operands of a fixed point operation is
5354 -- universal real, since in this case we don't do a conversion to a
5355 -- specific fixed-point type (instead the expander handles the case).
5356
5357 -- Set the type of the node to its universal interpretation because
5358 -- legality checks on an exponentiation operand need the context.
5359
5360 elsif (B_Typ = Universal_Integer or else B_Typ = Universal_Real)
5361 and then Present (Universal_Interpretation (L))
5362 and then Present (Universal_Interpretation (R))
5363 then
5364 Set_Etype (N, B_Typ);
5365 Resolve (L, Universal_Interpretation (L));
5366 Resolve (R, Universal_Interpretation (R));
5367
5368 elsif (B_Typ = Universal_Real
5369 or else Etype (N) = Universal_Fixed
5370 or else (Etype (N) = Any_Fixed
5371 and then Is_Fixed_Point_Type (B_Typ))
5372 or else (Is_Fixed_Point_Type (B_Typ)
5373 and then (Is_Integer_Or_Universal (L)
5374 or else
5375 Is_Integer_Or_Universal (R))))
5376 and then Nkind_In (N, N_Op_Multiply, N_Op_Divide)
5377 then
5378 if TL = Universal_Integer or else TR = Universal_Integer then
5379 Check_For_Visible_Operator (N, B_Typ);
5380 end if;
5381
5382 -- If context is a fixed type and one operand is integer, the other
5383 -- is resolved with the type of the context.
5384
5385 if Is_Fixed_Point_Type (B_Typ)
5386 and then (Base_Type (TL) = Base_Type (Standard_Integer)
5387 or else TL = Universal_Integer)
5388 then
5389 Resolve (R, B_Typ);
5390 Resolve (L, TL);
5391
5392 elsif Is_Fixed_Point_Type (B_Typ)
5393 and then (Base_Type (TR) = Base_Type (Standard_Integer)
5394 or else TR = Universal_Integer)
5395 then
5396 Resolve (L, B_Typ);
5397 Resolve (R, TR);
5398
5399 else
5400 Set_Mixed_Mode_Operand (L, TR);
5401 Set_Mixed_Mode_Operand (R, TL);
5402 end if;
5403
5404 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5405 -- multiplying operators from being used when the expected type is
5406 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5407 -- some cases where the expected type is actually Any_Real;
5408 -- Expected_Type_Is_Any_Real takes care of that case.
5409
5410 if Etype (N) = Universal_Fixed
5411 or else Etype (N) = Any_Fixed
5412 then
5413 if B_Typ = Universal_Fixed
5414 and then not Expected_Type_Is_Any_Real (N)
5415 and then not Nkind_In (Parent (N), N_Type_Conversion,
5416 N_Unchecked_Type_Conversion)
5417 then
5418 Error_Msg_N ("type cannot be determined from context!", N);
5419 Error_Msg_N ("\explicit conversion to result type required", N);
5420
5421 Set_Etype (L, Any_Type);
5422 Set_Etype (R, Any_Type);
5423
5424 else
5425 if Ada_Version = Ada_83
5426 and then Etype (N) = Universal_Fixed
5427 and then not
5428 Nkind_In (Parent (N), N_Type_Conversion,
5429 N_Unchecked_Type_Conversion)
5430 then
5431 Error_Msg_N
5432 ("(Ada 83) fixed-point operation needs explicit "
5433 & "conversion", N);
5434 end if;
5435
5436 -- The expected type is "any real type" in contexts like
5437
5438 -- type T is delta <universal_fixed-expression> ...
5439
5440 -- in which case we need to set the type to Universal_Real
5441 -- so that static expression evaluation will work properly.
5442
5443 if Expected_Type_Is_Any_Real (N) then
5444 Set_Etype (N, Universal_Real);
5445 else
5446 Set_Etype (N, B_Typ);
5447 end if;
5448 end if;
5449
5450 elsif Is_Fixed_Point_Type (B_Typ)
5451 and then (Is_Integer_Or_Universal (L)
5452 or else Nkind (L) = N_Real_Literal
5453 or else Nkind (R) = N_Real_Literal
5454 or else Is_Integer_Or_Universal (R))
5455 then
5456 Set_Etype (N, B_Typ);
5457
5458 elsif Etype (N) = Any_Fixed then
5459
5460 -- If no previous errors, this is only possible if one operand is
5461 -- overloaded and the context is universal. Resolve as such.
5462
5463 Set_Etype (N, B_Typ);
5464 end if;
5465
5466 else
5467 if (TL = Universal_Integer or else TL = Universal_Real)
5468 and then
5469 (TR = Universal_Integer or else TR = Universal_Real)
5470 then
5471 Check_For_Visible_Operator (N, B_Typ);
5472 end if;
5473
5474 -- If the context is Universal_Fixed and the operands are also
5475 -- universal fixed, this is an error, unless there is only one
5476 -- applicable fixed_point type (usually Duration).
5477
5478 if B_Typ = Universal_Fixed and then Etype (L) = Universal_Fixed then
5479 T := Unique_Fixed_Point_Type (N);
5480
5481 if T = Any_Type then
5482 Set_Etype (N, T);
5483 return;
5484 else
5485 Resolve (L, T);
5486 Resolve (R, T);
5487 end if;
5488
5489 else
5490 Resolve (L, B_Typ);
5491 Resolve (R, B_Typ);
5492 end if;
5493
5494 -- If one of the arguments was resolved to a non-universal type.
5495 -- label the result of the operation itself with the same type.
5496 -- Do the same for the universal argument, if any.
5497
5498 T := Intersect_Types (L, R);
5499 Set_Etype (N, Base_Type (T));
5500 Set_Operand_Type (L);
5501 Set_Operand_Type (R);
5502 end if;
5503
5504 Generate_Operator_Reference (N, Typ);
5505 Analyze_Dimension (N);
5506 Eval_Arithmetic_Op (N);
5507
5508 -- In SPARK, a multiplication or division with operands of fixed point
5509 -- types must be qualified or explicitly converted to identify the
5510 -- result type.
5511
5512 if (Is_Fixed_Point_Type (Etype (L))
5513 or else Is_Fixed_Point_Type (Etype (R)))
5514 and then Nkind_In (N, N_Op_Multiply, N_Op_Divide)
5515 and then
5516 not Nkind_In (Parent (N), N_Qualified_Expression, N_Type_Conversion)
5517 then
5518 Check_SPARK_05_Restriction
5519 ("operation should be qualified or explicitly converted", N);
5520 end if;
5521
5522 -- Set overflow and division checking bit
5523
5524 if Nkind (N) in N_Op then
5525 if not Overflow_Checks_Suppressed (Etype (N)) then
5526 Enable_Overflow_Check (N);
5527 end if;
5528
5529 -- Give warning if explicit division by zero
5530
5531 if Nkind_In (N, N_Op_Divide, N_Op_Rem, N_Op_Mod)
5532 and then not Division_Checks_Suppressed (Etype (N))
5533 then
5534 Rop := Right_Opnd (N);
5535
5536 if Compile_Time_Known_Value (Rop)
5537 and then ((Is_Integer_Type (Etype (Rop))
5538 and then Expr_Value (Rop) = Uint_0)
5539 or else
5540 (Is_Real_Type (Etype (Rop))
5541 and then Expr_Value_R (Rop) = Ureal_0))
5542 then
5543 -- Specialize the warning message according to the operation.
5544 -- When SPARK_Mode is On, force a warning instead of an error
5545 -- in that case, as this likely corresponds to deactivated
5546 -- code. The following warnings are for the case
5547
5548 case Nkind (N) is
5549 when N_Op_Divide =>
5550
5551 -- For division, we have two cases, for float division
5552 -- of an unconstrained float type, on a machine where
5553 -- Machine_Overflows is false, we don't get an exception
5554 -- at run-time, but rather an infinity or Nan. The Nan
5555 -- case is pretty obscure, so just warn about infinities.
5556
5557 if Is_Floating_Point_Type (Typ)
5558 and then not Is_Constrained (Typ)
5559 and then not Machine_Overflows_On_Target
5560 then
5561 Error_Msg_N
5562 ("float division by zero, may generate "
5563 & "'+'/'- infinity??", Right_Opnd (N));
5564
5565 -- For all other cases, we get a Constraint_Error
5566
5567 else
5568 Apply_Compile_Time_Constraint_Error
5569 (N, "division by zero??", CE_Divide_By_Zero,
5570 Loc => Sloc (Right_Opnd (N)),
5571 Warn => SPARK_Mode = On);
5572 end if;
5573
5574 when N_Op_Rem =>
5575 Apply_Compile_Time_Constraint_Error
5576 (N, "rem with zero divisor??", CE_Divide_By_Zero,
5577 Loc => Sloc (Right_Opnd (N)),
5578 Warn => SPARK_Mode = On);
5579
5580 when N_Op_Mod =>
5581 Apply_Compile_Time_Constraint_Error
5582 (N, "mod with zero divisor??", CE_Divide_By_Zero,
5583 Loc => Sloc (Right_Opnd (N)),
5584 Warn => SPARK_Mode = On);
5585
5586 -- Division by zero can only happen with division, rem,
5587 -- and mod operations.
5588
5589 when others =>
5590 raise Program_Error;
5591 end case;
5592
5593 -- In GNATprove mode, we enable the division check so that
5594 -- GNATprove will issue a message if it cannot be proved.
5595
5596 if GNATprove_Mode then
5597 Activate_Division_Check (N);
5598 end if;
5599
5600 -- Otherwise just set the flag to check at run time
5601
5602 else
5603 Activate_Division_Check (N);
5604 end if;
5605 end if;
5606
5607 -- If Restriction No_Implicit_Conditionals is active, then it is
5608 -- violated if either operand can be negative for mod, or for rem
5609 -- if both operands can be negative.
5610
5611 if Restriction_Check_Required (No_Implicit_Conditionals)
5612 and then Nkind_In (N, N_Op_Rem, N_Op_Mod)
5613 then
5614 declare
5615 Lo : Uint;
5616 Hi : Uint;
5617 OK : Boolean;
5618
5619 LNeg : Boolean;
5620 RNeg : Boolean;
5621 -- Set if corresponding operand might be negative
5622
5623 begin
5624 Determine_Range
5625 (Left_Opnd (N), OK, Lo, Hi, Assume_Valid => True);
5626 LNeg := (not OK) or else Lo < 0;
5627
5628 Determine_Range
5629 (Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True);
5630 RNeg := (not OK) or else Lo < 0;
5631
5632 -- Check if we will be generating conditionals. There are two
5633 -- cases where that can happen, first for REM, the only case
5634 -- is largest negative integer mod -1, where the division can
5635 -- overflow, but we still have to give the right result. The
5636 -- front end generates a test for this annoying case. Here we
5637 -- just test if both operands can be negative (that's what the
5638 -- expander does, so we match its logic here).
5639
5640 -- The second case is mod where either operand can be negative.
5641 -- In this case, the back end has to generate additional tests.
5642
5643 if (Nkind (N) = N_Op_Rem and then (LNeg and RNeg))
5644 or else
5645 (Nkind (N) = N_Op_Mod and then (LNeg or RNeg))
5646 then
5647 Check_Restriction (No_Implicit_Conditionals, N);
5648 end if;
5649 end;
5650 end if;
5651 end if;
5652
5653 Check_Unset_Reference (L);
5654 Check_Unset_Reference (R);
5655 end Resolve_Arithmetic_Op;
5656
5657 ------------------
5658 -- Resolve_Call --
5659 ------------------
5660
5661 procedure Resolve_Call (N : Node_Id; Typ : Entity_Id) is
5662 function Same_Or_Aliased_Subprograms
5663 (S : Entity_Id;
5664 E : Entity_Id) return Boolean;
5665 -- Returns True if the subprogram entity S is the same as E or else
5666 -- S is an alias of E.
5667
5668 ---------------------------------
5669 -- Same_Or_Aliased_Subprograms --
5670 ---------------------------------
5671
5672 function Same_Or_Aliased_Subprograms
5673 (S : Entity_Id;
5674 E : Entity_Id) return Boolean
5675 is
5676 Subp_Alias : constant Entity_Id := Alias (S);
5677 begin
5678 return S = E or else (Present (Subp_Alias) and then Subp_Alias = E);
5679 end Same_Or_Aliased_Subprograms;
5680
5681 -- Local variables
5682
5683 Loc : constant Source_Ptr := Sloc (N);
5684 Subp : constant Node_Id := Name (N);
5685 Body_Id : Entity_Id;
5686 I : Interp_Index;
5687 It : Interp;
5688 Nam : Entity_Id;
5689 Nam_Decl : Node_Id;
5690 Nam_UA : Entity_Id;
5691 Norm_OK : Boolean;
5692 Rtype : Entity_Id;
5693 Scop : Entity_Id;
5694
5695 -- Start of processing for Resolve_Call
5696
5697 begin
5698 -- The context imposes a unique interpretation with type Typ on a
5699 -- procedure or function call. Find the entity of the subprogram that
5700 -- yields the expected type, and propagate the corresponding formal
5701 -- constraints on the actuals. The caller has established that an
5702 -- interpretation exists, and emitted an error if not unique.
5703
5704 -- First deal with the case of a call to an access-to-subprogram,
5705 -- dereference made explicit in Analyze_Call.
5706
5707 if Ekind (Etype (Subp)) = E_Subprogram_Type then
5708 if not Is_Overloaded (Subp) then
5709 Nam := Etype (Subp);
5710
5711 else
5712 -- Find the interpretation whose type (a subprogram type) has a
5713 -- return type that is compatible with the context. Analysis of
5714 -- the node has established that one exists.
5715
5716 Nam := Empty;
5717
5718 Get_First_Interp (Subp, I, It);
5719 while Present (It.Typ) loop
5720 if Covers (Typ, Etype (It.Typ)) then
5721 Nam := It.Typ;
5722 exit;
5723 end if;
5724
5725 Get_Next_Interp (I, It);
5726 end loop;
5727
5728 if No (Nam) then
5729 raise Program_Error;
5730 end if;
5731 end if;
5732
5733 -- If the prefix is not an entity, then resolve it
5734
5735 if not Is_Entity_Name (Subp) then
5736 Resolve (Subp, Nam);
5737 end if;
5738
5739 -- For an indirect call, we always invalidate checks, since we do not
5740 -- know whether the subprogram is local or global. Yes we could do
5741 -- better here, e.g. by knowing that there are no local subprograms,
5742 -- but it does not seem worth the effort. Similarly, we kill all
5743 -- knowledge of current constant values.
5744
5745 Kill_Current_Values;
5746
5747 -- If this is a procedure call which is really an entry call, do
5748 -- the conversion of the procedure call to an entry call. Protected
5749 -- operations use the same circuitry because the name in the call
5750 -- can be an arbitrary expression with special resolution rules.
5751
5752 elsif Nkind_In (Subp, N_Selected_Component, N_Indexed_Component)
5753 or else (Is_Entity_Name (Subp)
5754 and then Ekind (Entity (Subp)) = E_Entry)
5755 then
5756 Resolve_Entry_Call (N, Typ);
5757 Check_Elab_Call (N);
5758
5759 -- Kill checks and constant values, as above for indirect case
5760 -- Who knows what happens when another task is activated?
5761
5762 Kill_Current_Values;
5763 return;
5764
5765 -- Normal subprogram call with name established in Resolve
5766
5767 elsif not (Is_Type (Entity (Subp))) then
5768 Nam := Entity (Subp);
5769 Set_Entity_With_Checks (Subp, Nam);
5770
5771 -- Otherwise we must have the case of an overloaded call
5772
5773 else
5774 pragma Assert (Is_Overloaded (Subp));
5775
5776 -- Initialize Nam to prevent warning (we know it will be assigned
5777 -- in the loop below, but the compiler does not know that).
5778
5779 Nam := Empty;
5780
5781 Get_First_Interp (Subp, I, It);
5782 while Present (It.Typ) loop
5783 if Covers (Typ, It.Typ) then
5784 Nam := It.Nam;
5785 Set_Entity_With_Checks (Subp, Nam);
5786 exit;
5787 end if;
5788
5789 Get_Next_Interp (I, It);
5790 end loop;
5791 end if;
5792
5793 if Is_Access_Subprogram_Type (Base_Type (Etype (Nam)))
5794 and then not Is_Access_Subprogram_Type (Base_Type (Typ))
5795 and then Nkind (Subp) /= N_Explicit_Dereference
5796 and then Present (Parameter_Associations (N))
5797 then
5798 -- The prefix is a parameterless function call that returns an access
5799 -- to subprogram. If parameters are present in the current call, add
5800 -- add an explicit dereference. We use the base type here because
5801 -- within an instance these may be subtypes.
5802
5803 -- The dereference is added either in Analyze_Call or here. Should
5804 -- be consolidated ???
5805
5806 Set_Is_Overloaded (Subp, False);
5807 Set_Etype (Subp, Etype (Nam));
5808 Insert_Explicit_Dereference (Subp);
5809 Nam := Designated_Type (Etype (Nam));
5810 Resolve (Subp, Nam);
5811 end if;
5812
5813 -- Check that a call to Current_Task does not occur in an entry body
5814
5815 if Is_RTE (Nam, RE_Current_Task) then
5816 declare
5817 P : Node_Id;
5818
5819 begin
5820 P := N;
5821 loop
5822 P := Parent (P);
5823
5824 -- Exclude calls that occur within the default of a formal
5825 -- parameter of the entry, since those are evaluated outside
5826 -- of the body.
5827
5828 exit when No (P) or else Nkind (P) = N_Parameter_Specification;
5829
5830 if Nkind (P) = N_Entry_Body
5831 or else (Nkind (P) = N_Subprogram_Body
5832 and then Is_Entry_Barrier_Function (P))
5833 then
5834 Rtype := Etype (N);
5835 Error_Msg_Warn := SPARK_Mode /= On;
5836 Error_Msg_NE
5837 ("& should not be used in entry body (RM C.7(17))<<",
5838 N, Nam);
5839 Error_Msg_NE ("\Program_Error [<<", N, Nam);
5840 Rewrite (N,
5841 Make_Raise_Program_Error (Loc,
5842 Reason => PE_Current_Task_In_Entry_Body));
5843 Set_Etype (N, Rtype);
5844 return;
5845 end if;
5846 end loop;
5847 end;
5848 end if;
5849
5850 -- Check that a procedure call does not occur in the context of the
5851 -- entry call statement of a conditional or timed entry call. Note that
5852 -- the case of a call to a subprogram renaming of an entry will also be
5853 -- rejected. The test for N not being an N_Entry_Call_Statement is
5854 -- defensive, covering the possibility that the processing of entry
5855 -- calls might reach this point due to later modifications of the code
5856 -- above.
5857
5858 if Nkind (Parent (N)) = N_Entry_Call_Alternative
5859 and then Nkind (N) /= N_Entry_Call_Statement
5860 and then Entry_Call_Statement (Parent (N)) = N
5861 then
5862 if Ada_Version < Ada_2005 then
5863 Error_Msg_N ("entry call required in select statement", N);
5864
5865 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5866 -- for a procedure_or_entry_call, the procedure_name or
5867 -- procedure_prefix of the procedure_call_statement shall denote
5868 -- an entry renamed by a procedure, or (a view of) a primitive
5869 -- subprogram of a limited interface whose first parameter is
5870 -- a controlling parameter.
5871
5872 elsif Nkind (N) = N_Procedure_Call_Statement
5873 and then not Is_Renamed_Entry (Nam)
5874 and then not Is_Controlling_Limited_Procedure (Nam)
5875 then
5876 Error_Msg_N
5877 ("entry call or dispatching primitive of interface required", N);
5878 end if;
5879 end if;
5880
5881 -- If the SPARK_05 restriction is active, we are not allowed
5882 -- to have a call to a subprogram before we see its completion.
5883
5884 if not Has_Completion (Nam)
5885 and then Restriction_Check_Required (SPARK_05)
5886
5887 -- Don't flag strange internal calls
5888
5889 and then Comes_From_Source (N)
5890 and then Comes_From_Source (Nam)
5891
5892 -- Only flag calls in extended main source
5893
5894 and then In_Extended_Main_Source_Unit (Nam)
5895 and then In_Extended_Main_Source_Unit (N)
5896
5897 -- Exclude enumeration literals from this processing
5898
5899 and then Ekind (Nam) /= E_Enumeration_Literal
5900 then
5901 Check_SPARK_05_Restriction
5902 ("call to subprogram cannot appear before its body", N);
5903 end if;
5904
5905 -- Check that this is not a call to a protected procedure or entry from
5906 -- within a protected function.
5907
5908 Check_Internal_Protected_Use (N, Nam);
5909
5910 -- Freeze the subprogram name if not in a spec-expression. Note that
5911 -- we freeze procedure calls as well as function calls. Procedure calls
5912 -- are not frozen according to the rules (RM 13.14(14)) because it is
5913 -- impossible to have a procedure call to a non-frozen procedure in
5914 -- pure Ada, but in the code that we generate in the expander, this
5915 -- rule needs extending because we can generate procedure calls that
5916 -- need freezing.
5917
5918 -- In Ada 2012, expression functions may be called within pre/post
5919 -- conditions of subsequent functions or expression functions. Such
5920 -- calls do not freeze when they appear within generated bodies,
5921 -- (including the body of another expression function) which would
5922 -- place the freeze node in the wrong scope. An expression function
5923 -- is frozen in the usual fashion, by the appearance of a real body,
5924 -- or at the end of a declarative part.
5925
5926 if Is_Entity_Name (Subp)
5927 and then not In_Spec_Expression
5928 and then not Is_Expression_Function_Or_Completion (Current_Scope)
5929 and then
5930 (not Is_Expression_Function_Or_Completion (Entity (Subp))
5931 or else Scope (Entity (Subp)) = Current_Scope)
5932 then
5933 Freeze_Expression (Subp);
5934 end if;
5935
5936 -- For a predefined operator, the type of the result is the type imposed
5937 -- by context, except for a predefined operation on universal fixed.
5938 -- Otherwise The type of the call is the type returned by the subprogram
5939 -- being called.
5940
5941 if Is_Predefined_Op (Nam) then
5942 if Etype (N) /= Universal_Fixed then
5943 Set_Etype (N, Typ);
5944 end if;
5945
5946 -- If the subprogram returns an array type, and the context requires the
5947 -- component type of that array type, the node is really an indexing of
5948 -- the parameterless call. Resolve as such. A pathological case occurs
5949 -- when the type of the component is an access to the array type. In
5950 -- this case the call is truly ambiguous.
5951
5952 elsif (Needs_No_Actuals (Nam) or else Needs_One_Actual (Nam))
5953 and then
5954 ((Is_Array_Type (Etype (Nam))
5955 and then Covers (Typ, Component_Type (Etype (Nam))))
5956 or else
5957 (Is_Access_Type (Etype (Nam))
5958 and then Is_Array_Type (Designated_Type (Etype (Nam)))
5959 and then
5960 Covers (Typ, Component_Type (Designated_Type (Etype (Nam))))))
5961 then
5962 declare
5963 Index_Node : Node_Id;
5964 New_Subp : Node_Id;
5965 Ret_Type : constant Entity_Id := Etype (Nam);
5966
5967 begin
5968 if Is_Access_Type (Ret_Type)
5969 and then Ret_Type = Component_Type (Designated_Type (Ret_Type))
5970 then
5971 Error_Msg_N
5972 ("cannot disambiguate function call and indexing", N);
5973 else
5974 New_Subp := Relocate_Node (Subp);
5975
5976 -- The called entity may be an explicit dereference, in which
5977 -- case there is no entity to set.
5978
5979 if Nkind (New_Subp) /= N_Explicit_Dereference then
5980 Set_Entity (Subp, Nam);
5981 end if;
5982
5983 if (Is_Array_Type (Ret_Type)
5984 and then Component_Type (Ret_Type) /= Any_Type)
5985 or else
5986 (Is_Access_Type (Ret_Type)
5987 and then
5988 Component_Type (Designated_Type (Ret_Type)) /= Any_Type)
5989 then
5990 if Needs_No_Actuals (Nam) then
5991
5992 -- Indexed call to a parameterless function
5993
5994 Index_Node :=
5995 Make_Indexed_Component (Loc,
5996 Prefix =>
5997 Make_Function_Call (Loc, Name => New_Subp),
5998 Expressions => Parameter_Associations (N));
5999 else
6000 -- An Ada 2005 prefixed call to a primitive operation
6001 -- whose first parameter is the prefix. This prefix was
6002 -- prepended to the parameter list, which is actually a
6003 -- list of indexes. Remove the prefix in order to build
6004 -- the proper indexed component.
6005
6006 Index_Node :=
6007 Make_Indexed_Component (Loc,
6008 Prefix =>
6009 Make_Function_Call (Loc,
6010 Name => New_Subp,
6011 Parameter_Associations =>
6012 New_List
6013 (Remove_Head (Parameter_Associations (N)))),
6014 Expressions => Parameter_Associations (N));
6015 end if;
6016
6017 -- Preserve the parenthesis count of the node
6018
6019 Set_Paren_Count (Index_Node, Paren_Count (N));
6020
6021 -- Since we are correcting a node classification error made
6022 -- by the parser, we call Replace rather than Rewrite.
6023
6024 Replace (N, Index_Node);
6025
6026 Set_Etype (Prefix (N), Ret_Type);
6027 Set_Etype (N, Typ);
6028 Resolve_Indexed_Component (N, Typ);
6029 Check_Elab_Call (Prefix (N));
6030 end if;
6031 end if;
6032
6033 return;
6034 end;
6035
6036 else
6037 Set_Etype (N, Etype (Nam));
6038 end if;
6039
6040 -- In the case where the call is to an overloaded subprogram, Analyze
6041 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6042 -- such a case Normalize_Actuals needs to be called once more to order
6043 -- the actuals correctly. Otherwise the call will have the ordering
6044 -- given by the last overloaded subprogram whether this is the correct
6045 -- one being called or not.
6046
6047 if Is_Overloaded (Subp) then
6048 Normalize_Actuals (N, Nam, False, Norm_OK);
6049 pragma Assert (Norm_OK);
6050 end if;
6051
6052 -- In any case, call is fully resolved now. Reset Overload flag, to
6053 -- prevent subsequent overload resolution if node is analyzed again
6054
6055 Set_Is_Overloaded (Subp, False);
6056 Set_Is_Overloaded (N, False);
6057
6058 -- A Ghost entity must appear in a specific context
6059
6060 if Is_Ghost_Entity (Nam) and then Comes_From_Source (N) then
6061 Check_Ghost_Context (Nam, N);
6062 end if;
6063
6064 -- If we are calling the current subprogram from immediately within its
6065 -- body, then that is the case where we can sometimes detect cases of
6066 -- infinite recursion statically. Do not try this in case restriction
6067 -- No_Recursion is in effect anyway, and do it only for source calls.
6068
6069 if Comes_From_Source (N) then
6070 Scop := Current_Scope;
6071
6072 -- Check violation of SPARK_05 restriction which does not permit
6073 -- a subprogram body to contain a call to the subprogram directly.
6074
6075 if Restriction_Check_Required (SPARK_05)
6076 and then Same_Or_Aliased_Subprograms (Nam, Scop)
6077 then
6078 Check_SPARK_05_Restriction
6079 ("subprogram may not contain direct call to itself", N);
6080 end if;
6081
6082 -- Issue warning for possible infinite recursion in the absence
6083 -- of the No_Recursion restriction.
6084
6085 if Same_Or_Aliased_Subprograms (Nam, Scop)
6086 and then not Restriction_Active (No_Recursion)
6087 and then Check_Infinite_Recursion (N)
6088 then
6089 -- Here we detected and flagged an infinite recursion, so we do
6090 -- not need to test the case below for further warnings. Also we
6091 -- are all done if we now have a raise SE node.
6092
6093 if Nkind (N) = N_Raise_Storage_Error then
6094 return;
6095 end if;
6096
6097 -- If call is to immediately containing subprogram, then check for
6098 -- the case of a possible run-time detectable infinite recursion.
6099
6100 else
6101 Scope_Loop : while Scop /= Standard_Standard loop
6102 if Same_Or_Aliased_Subprograms (Nam, Scop) then
6103
6104 -- Although in general case, recursion is not statically
6105 -- checkable, the case of calling an immediately containing
6106 -- subprogram is easy to catch.
6107
6108 Check_Restriction (No_Recursion, N);
6109
6110 -- If the recursive call is to a parameterless subprogram,
6111 -- then even if we can't statically detect infinite
6112 -- recursion, this is pretty suspicious, and we output a
6113 -- warning. Furthermore, we will try later to detect some
6114 -- cases here at run time by expanding checking code (see
6115 -- Detect_Infinite_Recursion in package Exp_Ch6).
6116
6117 -- If the recursive call is within a handler, do not emit a
6118 -- warning, because this is a common idiom: loop until input
6119 -- is correct, catch illegal input in handler and restart.
6120
6121 if No (First_Formal (Nam))
6122 and then Etype (Nam) = Standard_Void_Type
6123 and then not Error_Posted (N)
6124 and then Nkind (Parent (N)) /= N_Exception_Handler
6125 then
6126 -- For the case of a procedure call. We give the message
6127 -- only if the call is the first statement in a sequence
6128 -- of statements, or if all previous statements are
6129 -- simple assignments. This is simply a heuristic to
6130 -- decrease false positives, without losing too many good
6131 -- warnings. The idea is that these previous statements
6132 -- may affect global variables the procedure depends on.
6133 -- We also exclude raise statements, that may arise from
6134 -- constraint checks and are probably unrelated to the
6135 -- intended control flow.
6136
6137 if Nkind (N) = N_Procedure_Call_Statement
6138 and then Is_List_Member (N)
6139 then
6140 declare
6141 P : Node_Id;
6142 begin
6143 P := Prev (N);
6144 while Present (P) loop
6145 if not Nkind_In (P, N_Assignment_Statement,
6146 N_Raise_Constraint_Error)
6147 then
6148 exit Scope_Loop;
6149 end if;
6150
6151 Prev (P);
6152 end loop;
6153 end;
6154 end if;
6155
6156 -- Do not give warning if we are in a conditional context
6157
6158 declare
6159 K : constant Node_Kind := Nkind (Parent (N));
6160 begin
6161 if (K = N_Loop_Statement
6162 and then Present (Iteration_Scheme (Parent (N))))
6163 or else K = N_If_Statement
6164 or else K = N_Elsif_Part
6165 or else K = N_Case_Statement_Alternative
6166 then
6167 exit Scope_Loop;
6168 end if;
6169 end;
6170
6171 -- Here warning is to be issued
6172
6173 Set_Has_Recursive_Call (Nam);
6174 Error_Msg_Warn := SPARK_Mode /= On;
6175 Error_Msg_N ("possible infinite recursion<<!", N);
6176 Error_Msg_N ("\Storage_Error ]<<!", N);
6177 end if;
6178
6179 exit Scope_Loop;
6180 end if;
6181
6182 Scop := Scope (Scop);
6183 end loop Scope_Loop;
6184 end if;
6185 end if;
6186
6187 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6188
6189 Check_Obsolescent_2005_Entity (Nam, Subp);
6190
6191 -- If subprogram name is a predefined operator, it was given in
6192 -- functional notation. Replace call node with operator node, so
6193 -- that actuals can be resolved appropriately.
6194
6195 if Is_Predefined_Op (Nam) or else Ekind (Nam) = E_Operator then
6196 Make_Call_Into_Operator (N, Typ, Entity (Name (N)));
6197 return;
6198
6199 elsif Present (Alias (Nam))
6200 and then Is_Predefined_Op (Alias (Nam))
6201 then
6202 Resolve_Actuals (N, Nam);
6203 Make_Call_Into_Operator (N, Typ, Alias (Nam));
6204 return;
6205 end if;
6206
6207 -- Create a transient scope if the resulting type requires it
6208
6209 -- There are several notable exceptions:
6210
6211 -- a) In init procs, the transient scope overhead is not needed, and is
6212 -- even incorrect when the call is a nested initialization call for a
6213 -- component whose expansion may generate adjust calls. However, if the
6214 -- call is some other procedure call within an initialization procedure
6215 -- (for example a call to Create_Task in the init_proc of the task
6216 -- run-time record) a transient scope must be created around this call.
6217
6218 -- b) Enumeration literal pseudo-calls need no transient scope
6219
6220 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6221 -- functions) do not use the secondary stack even though the return
6222 -- type may be unconstrained.
6223
6224 -- d) Calls to a build-in-place function, since such functions may
6225 -- allocate their result directly in a target object, and cases where
6226 -- the result does get allocated in the secondary stack are checked for
6227 -- within the specialized Exp_Ch6 procedures for expanding those
6228 -- build-in-place calls.
6229
6230 -- e) If the subprogram is marked Inline_Always, then even if it returns
6231 -- an unconstrained type the call does not require use of the secondary
6232 -- stack. However, inlining will only take place if the body to inline
6233 -- is already present. It may not be available if e.g. the subprogram is
6234 -- declared in a child instance.
6235
6236 -- If this is an initialization call for a type whose construction
6237 -- uses the secondary stack, and it is not a nested call to initialize
6238 -- a component, we do need to create a transient scope for it. We
6239 -- check for this by traversing the type in Check_Initialization_Call.
6240
6241 if Is_Inlined (Nam)
6242 and then Has_Pragma_Inline (Nam)
6243 and then Nkind (Unit_Declaration_Node (Nam)) = N_Subprogram_Declaration
6244 and then Present (Body_To_Inline (Unit_Declaration_Node (Nam)))
6245 then
6246 null;
6247
6248 elsif Ekind (Nam) = E_Enumeration_Literal
6249 or else Is_Build_In_Place_Function (Nam)
6250 or else Is_Intrinsic_Subprogram (Nam)
6251 then
6252 null;
6253
6254 elsif Expander_Active
6255 and then Is_Type (Etype (Nam))
6256 and then Requires_Transient_Scope (Etype (Nam))
6257 and then
6258 (not Within_Init_Proc
6259 or else
6260 (not Is_Init_Proc (Nam) and then Ekind (Nam) /= E_Function))
6261 then
6262 Establish_Transient_Scope (N, Sec_Stack => True);
6263
6264 -- If the call appears within the bounds of a loop, it will
6265 -- be rewritten and reanalyzed, nothing left to do here.
6266
6267 if Nkind (N) /= N_Function_Call then
6268 return;
6269 end if;
6270
6271 elsif Is_Init_Proc (Nam)
6272 and then not Within_Init_Proc
6273 then
6274 Check_Initialization_Call (N, Nam);
6275 end if;
6276
6277 -- A protected function cannot be called within the definition of the
6278 -- enclosing protected type, unless it is part of a pre/postcondition
6279 -- on another protected operation.
6280
6281 if Is_Protected_Type (Scope (Nam))
6282 and then In_Open_Scopes (Scope (Nam))
6283 and then not Has_Completion (Scope (Nam))
6284 and then not In_Spec_Expression
6285 then
6286 Error_Msg_NE
6287 ("& cannot be called before end of protected definition", N, Nam);
6288 end if;
6289
6290 -- Propagate interpretation to actuals, and add default expressions
6291 -- where needed.
6292
6293 if Present (First_Formal (Nam)) then
6294 Resolve_Actuals (N, Nam);
6295
6296 -- Overloaded literals are rewritten as function calls, for purpose of
6297 -- resolution. After resolution, we can replace the call with the
6298 -- literal itself.
6299
6300 elsif Ekind (Nam) = E_Enumeration_Literal then
6301 Copy_Node (Subp, N);
6302 Resolve_Entity_Name (N, Typ);
6303
6304 -- Avoid validation, since it is a static function call
6305
6306 Generate_Reference (Nam, Subp);
6307 return;
6308 end if;
6309
6310 -- If the subprogram is not global, then kill all saved values and
6311 -- checks. This is a bit conservative, since in many cases we could do
6312 -- better, but it is not worth the effort. Similarly, we kill constant
6313 -- values. However we do not need to do this for internal entities
6314 -- (unless they are inherited user-defined subprograms), since they
6315 -- are not in the business of molesting local values.
6316
6317 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6318 -- kill all checks and values for calls to global subprograms. This
6319 -- takes care of the case where an access to a local subprogram is
6320 -- taken, and could be passed directly or indirectly and then called
6321 -- from almost any context.
6322
6323 -- Note: we do not do this step till after resolving the actuals. That
6324 -- way we still take advantage of the current value information while
6325 -- scanning the actuals.
6326
6327 -- We suppress killing values if we are processing the nodes associated
6328 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6329 -- type kills all the values as part of analyzing the code that
6330 -- initializes the dispatch tables.
6331
6332 if Inside_Freezing_Actions = 0
6333 and then (not Is_Library_Level_Entity (Nam)
6334 or else Suppress_Value_Tracking_On_Call
6335 (Nearest_Dynamic_Scope (Current_Scope)))
6336 and then (Comes_From_Source (Nam)
6337 or else (Present (Alias (Nam))
6338 and then Comes_From_Source (Alias (Nam))))
6339 then
6340 Kill_Current_Values;
6341 end if;
6342
6343 -- If we are warning about unread OUT parameters, this is the place to
6344 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6345 -- after the above call to Kill_Current_Values (since that call clears
6346 -- the Last_Assignment field of all local variables).
6347
6348 if (Warn_On_Modified_Unread or Warn_On_All_Unread_Out_Parameters)
6349 and then Comes_From_Source (N)
6350 and then In_Extended_Main_Source_Unit (N)
6351 then
6352 declare
6353 F : Entity_Id;
6354 A : Node_Id;
6355
6356 begin
6357 F := First_Formal (Nam);
6358 A := First_Actual (N);
6359 while Present (F) and then Present (A) loop
6360 if Ekind_In (F, E_Out_Parameter, E_In_Out_Parameter)
6361 and then Warn_On_Modified_As_Out_Parameter (F)
6362 and then Is_Entity_Name (A)
6363 and then Present (Entity (A))
6364 and then Comes_From_Source (N)
6365 and then Safe_To_Capture_Value (N, Entity (A))
6366 then
6367 Set_Last_Assignment (Entity (A), A);
6368 end if;
6369
6370 Next_Formal (F);
6371 Next_Actual (A);
6372 end loop;
6373 end;
6374 end if;
6375
6376 -- If the subprogram is a primitive operation, check whether or not
6377 -- it is a correct dispatching call.
6378
6379 if Is_Overloadable (Nam)
6380 and then Is_Dispatching_Operation (Nam)
6381 then
6382 Check_Dispatching_Call (N);
6383
6384 elsif Ekind (Nam) /= E_Subprogram_Type
6385 and then Is_Abstract_Subprogram (Nam)
6386 and then not In_Instance
6387 then
6388 Error_Msg_NE ("cannot call abstract subprogram &!", N, Nam);
6389 end if;
6390
6391 -- If this is a dispatching call, generate the appropriate reference,
6392 -- for better source navigation in GPS.
6393
6394 if Is_Overloadable (Nam)
6395 and then Present (Controlling_Argument (N))
6396 then
6397 Generate_Reference (Nam, Subp, 'R');
6398
6399 -- Normal case, not a dispatching call: generate a call reference
6400
6401 else
6402 Generate_Reference (Nam, Subp, 's');
6403 end if;
6404
6405 if Is_Intrinsic_Subprogram (Nam) then
6406 Check_Intrinsic_Call (N);
6407 end if;
6408
6409 -- Check for violation of restriction No_Specific_Termination_Handlers
6410 -- and warn on a potentially blocking call to Abort_Task.
6411
6412 if Restriction_Check_Required (No_Specific_Termination_Handlers)
6413 and then (Is_RTE (Nam, RE_Set_Specific_Handler)
6414 or else
6415 Is_RTE (Nam, RE_Specific_Handler))
6416 then
6417 Check_Restriction (No_Specific_Termination_Handlers, N);
6418
6419 elsif Is_RTE (Nam, RE_Abort_Task) then
6420 Check_Potentially_Blocking_Operation (N);
6421 end if;
6422
6423 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6424 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6425 -- need to check the second argument to determine whether it is an
6426 -- absolute or relative timing event.
6427
6428 if Restriction_Check_Required (No_Relative_Delay)
6429 and then Is_RTE (Nam, RE_Set_Handler)
6430 and then Is_RTE (Etype (Next_Actual (First_Actual (N))), RE_Time_Span)
6431 then
6432 Check_Restriction (No_Relative_Delay, N);
6433 end if;
6434
6435 -- Issue an error for a call to an eliminated subprogram. This routine
6436 -- will not perform the check if the call appears within a default
6437 -- expression.
6438
6439 Check_For_Eliminated_Subprogram (Subp, Nam);
6440
6441 -- In formal mode, the primitive operations of a tagged type or type
6442 -- extension do not include functions that return the tagged type.
6443
6444 if Nkind (N) = N_Function_Call
6445 and then Is_Tagged_Type (Etype (N))
6446 and then Is_Entity_Name (Name (N))
6447 and then Is_Inherited_Operation_For_Type (Entity (Name (N)), Etype (N))
6448 then
6449 Check_SPARK_05_Restriction ("function not inherited", N);
6450 end if;
6451
6452 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6453 -- class-wide and the call dispatches on result in a context that does
6454 -- not provide a tag, the call raises Program_Error.
6455
6456 if Nkind (N) = N_Function_Call
6457 and then In_Instance
6458 and then Is_Generic_Actual_Type (Typ)
6459 and then Is_Class_Wide_Type (Typ)
6460 and then Has_Controlling_Result (Nam)
6461 and then Nkind (Parent (N)) = N_Object_Declaration
6462 then
6463 -- Verify that none of the formals are controlling
6464
6465 declare
6466 Call_OK : Boolean := False;
6467 F : Entity_Id;
6468
6469 begin
6470 F := First_Formal (Nam);
6471 while Present (F) loop
6472 if Is_Controlling_Formal (F) then
6473 Call_OK := True;
6474 exit;
6475 end if;
6476
6477 Next_Formal (F);
6478 end loop;
6479
6480 if not Call_OK then
6481 Error_Msg_Warn := SPARK_Mode /= On;
6482 Error_Msg_N ("!cannot determine tag of result<<", N);
6483 Error_Msg_N ("\Program_Error [<<!", N);
6484 Insert_Action (N,
6485 Make_Raise_Program_Error (Sloc (N),
6486 Reason => PE_Explicit_Raise));
6487 end if;
6488 end;
6489 end if;
6490
6491 -- Check for calling a function with OUT or IN OUT parameter when the
6492 -- calling context (us right now) is not Ada 2012, so does not allow
6493 -- OUT or IN OUT parameters in function calls. Functions declared in
6494 -- a predefined unit are OK, as they may be called indirectly from a
6495 -- user-declared instantiation.
6496
6497 if Ada_Version < Ada_2012
6498 and then Ekind (Nam) = E_Function
6499 and then Has_Out_Or_In_Out_Parameter (Nam)
6500 and then not In_Predefined_Unit (Nam)
6501 then
6502 Error_Msg_NE ("& has at least one OUT or `IN OUT` parameter", N, Nam);
6503 Error_Msg_N ("\call to this function only allowed in Ada 2012", N);
6504 end if;
6505
6506 -- Check the dimensions of the actuals in the call. For function calls,
6507 -- propagate the dimensions from the returned type to N.
6508
6509 Analyze_Dimension_Call (N, Nam);
6510
6511 -- All done, evaluate call and deal with elaboration issues
6512
6513 Eval_Call (N);
6514 Check_Elab_Call (N);
6515
6516 -- In GNATprove mode, expansion is disabled, but we want to inline some
6517 -- subprograms to facilitate formal verification. Indirect calls through
6518 -- a subprogram type or within a generic cannot be inlined. Inlining is
6519 -- performed only for calls subject to SPARK_Mode on.
6520
6521 if GNATprove_Mode
6522 and then SPARK_Mode = On
6523 and then Is_Overloadable (Nam)
6524 and then not Inside_A_Generic
6525 then
6526 Nam_UA := Ultimate_Alias (Nam);
6527 Nam_Decl := Unit_Declaration_Node (Nam_UA);
6528
6529 if Nkind (Nam_Decl) = N_Subprogram_Declaration then
6530 Body_Id := Corresponding_Body (Nam_Decl);
6531
6532 -- Nothing to do if the subprogram is not eligible for inlining in
6533 -- GNATprove mode.
6534
6535 if not Is_Inlined_Always (Nam_UA)
6536 or else not Can_Be_Inlined_In_GNATprove_Mode (Nam_UA, Body_Id)
6537 then
6538 null;
6539
6540 -- Calls cannot be inlined inside assertions, as GNATprove treats
6541 -- assertions as logic expressions.
6542
6543 elsif In_Assertion_Expr /= 0 then
6544 Cannot_Inline
6545 ("cannot inline & (in assertion expression)?", N, Nam_UA);
6546
6547 -- Calls cannot be inlined inside default expressions
6548
6549 elsif In_Default_Expr then
6550 Cannot_Inline
6551 ("cannot inline & (in default expression)?", N, Nam_UA);
6552
6553 -- Inlining should not be performed during pre-analysis
6554
6555 elsif Full_Analysis then
6556
6557 -- With the one-pass inlining technique, a call cannot be
6558 -- inlined if the corresponding body has not been seen yet.
6559
6560 if No (Body_Id) then
6561 Cannot_Inline
6562 ("cannot inline & (body not seen yet)?", N, Nam_UA);
6563
6564 -- Nothing to do if there is no body to inline, indicating that
6565 -- the subprogram is not suitable for inlining in GNATprove
6566 -- mode.
6567
6568 elsif No (Body_To_Inline (Nam_Decl)) then
6569 null;
6570
6571 -- Do not inline calls inside expression functions, as this
6572 -- would prevent interpreting them as logical formulas in
6573 -- GNATprove.
6574
6575 elsif Present (Current_Subprogram)
6576 and then
6577 Is_Expression_Function_Or_Completion (Current_Subprogram)
6578 then
6579 Cannot_Inline
6580 ("cannot inline & (inside expression function)?",
6581 N, Nam_UA);
6582
6583 -- Calls cannot be inlined inside potentially unevaluated
6584 -- expressions, as this would create complex actions inside
6585 -- expressions, that are not handled by GNATprove.
6586
6587 elsif Is_Potentially_Unevaluated (N) then
6588 Cannot_Inline
6589 ("cannot inline & (in potentially unevaluated context)?",
6590 N, Nam_UA);
6591
6592 -- Otherwise, inline the call
6593
6594 else
6595 Expand_Inlined_Call (N, Nam_UA, Nam);
6596 end if;
6597 end if;
6598 end if;
6599 end if;
6600
6601 Warn_On_Overlapping_Actuals (Nam, N);
6602 end Resolve_Call;
6603
6604 -----------------------------
6605 -- Resolve_Case_Expression --
6606 -----------------------------
6607
6608 procedure Resolve_Case_Expression (N : Node_Id; Typ : Entity_Id) is
6609 Alt : Node_Id;
6610 Alt_Expr : Node_Id;
6611 Alt_Typ : Entity_Id;
6612 Is_Dyn : Boolean;
6613
6614 begin
6615 Alt := First (Alternatives (N));
6616 while Present (Alt) loop
6617 Alt_Expr := Expression (Alt);
6618 Resolve (Alt_Expr, Typ);
6619 Alt_Typ := Etype (Alt_Expr);
6620
6621 -- When the expression is of a scalar subtype different from the
6622 -- result subtype, then insert a conversion to ensure the generation
6623 -- of a constraint check.
6624
6625 if Is_Scalar_Type (Alt_Typ) and then Alt_Typ /= Typ then
6626 Rewrite (Alt_Expr, Convert_To (Typ, Alt_Expr));
6627 Analyze_And_Resolve (Alt_Expr, Typ);
6628 end if;
6629
6630 Next (Alt);
6631 end loop;
6632
6633 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6634 -- dynamically tagged must be known statically.
6635
6636 if Is_Tagged_Type (Typ) and then not Is_Class_Wide_Type (Typ) then
6637 Alt := First (Alternatives (N));
6638 Is_Dyn := Is_Dynamically_Tagged (Expression (Alt));
6639
6640 while Present (Alt) loop
6641 if Is_Dynamically_Tagged (Expression (Alt)) /= Is_Dyn then
6642 Error_Msg_N
6643 ("all or none of the dependent expressions can be "
6644 & "dynamically tagged", N);
6645 end if;
6646
6647 Next (Alt);
6648 end loop;
6649 end if;
6650
6651 Set_Etype (N, Typ);
6652 Eval_Case_Expression (N);
6653 end Resolve_Case_Expression;
6654
6655 -------------------------------
6656 -- Resolve_Character_Literal --
6657 -------------------------------
6658
6659 procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id) is
6660 B_Typ : constant Entity_Id := Base_Type (Typ);
6661 C : Entity_Id;
6662
6663 begin
6664 -- Verify that the character does belong to the type of the context
6665
6666 Set_Etype (N, B_Typ);
6667 Eval_Character_Literal (N);
6668
6669 -- Wide_Wide_Character literals must always be defined, since the set
6670 -- of wide wide character literals is complete, i.e. if a character
6671 -- literal is accepted by the parser, then it is OK for wide wide
6672 -- character (out of range character literals are rejected).
6673
6674 if Root_Type (B_Typ) = Standard_Wide_Wide_Character then
6675 return;
6676
6677 -- Always accept character literal for type Any_Character, which
6678 -- occurs in error situations and in comparisons of literals, both
6679 -- of which should accept all literals.
6680
6681 elsif B_Typ = Any_Character then
6682 return;
6683
6684 -- For Standard.Character or a type derived from it, check that the
6685 -- literal is in range.
6686
6687 elsif Root_Type (B_Typ) = Standard_Character then
6688 if In_Character_Range (UI_To_CC (Char_Literal_Value (N))) then
6689 return;
6690 end if;
6691
6692 -- For Standard.Wide_Character or a type derived from it, check that the
6693 -- literal is in range.
6694
6695 elsif Root_Type (B_Typ) = Standard_Wide_Character then
6696 if In_Wide_Character_Range (UI_To_CC (Char_Literal_Value (N))) then
6697 return;
6698 end if;
6699
6700 -- For Standard.Wide_Wide_Character or a type derived from it, we
6701 -- know the literal is in range, since the parser checked.
6702
6703 elsif Root_Type (B_Typ) = Standard_Wide_Wide_Character then
6704 return;
6705
6706 -- If the entity is already set, this has already been resolved in a
6707 -- generic context, or comes from expansion. Nothing else to do.
6708
6709 elsif Present (Entity (N)) then
6710 return;
6711
6712 -- Otherwise we have a user defined character type, and we can use the
6713 -- standard visibility mechanisms to locate the referenced entity.
6714
6715 else
6716 C := Current_Entity (N);
6717 while Present (C) loop
6718 if Etype (C) = B_Typ then
6719 Set_Entity_With_Checks (N, C);
6720 Generate_Reference (C, N);
6721 return;
6722 end if;
6723
6724 C := Homonym (C);
6725 end loop;
6726 end if;
6727
6728 -- If we fall through, then the literal does not match any of the
6729 -- entries of the enumeration type. This isn't just a constraint error
6730 -- situation, it is an illegality (see RM 4.2).
6731
6732 Error_Msg_NE
6733 ("character not defined for }", N, First_Subtype (B_Typ));
6734 end Resolve_Character_Literal;
6735
6736 ---------------------------
6737 -- Resolve_Comparison_Op --
6738 ---------------------------
6739
6740 -- Context requires a boolean type, and plays no role in resolution.
6741 -- Processing identical to that for equality operators. The result type is
6742 -- the base type, which matters when pathological subtypes of booleans with
6743 -- limited ranges are used.
6744
6745 procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id) is
6746 L : constant Node_Id := Left_Opnd (N);
6747 R : constant Node_Id := Right_Opnd (N);
6748 T : Entity_Id;
6749
6750 begin
6751 -- If this is an intrinsic operation which is not predefined, use the
6752 -- types of its declared arguments to resolve the possibly overloaded
6753 -- operands. Otherwise the operands are unambiguous and specify the
6754 -- expected type.
6755
6756 if Scope (Entity (N)) /= Standard_Standard then
6757 T := Etype (First_Entity (Entity (N)));
6758
6759 else
6760 T := Find_Unique_Type (L, R);
6761
6762 if T = Any_Fixed then
6763 T := Unique_Fixed_Point_Type (L);
6764 end if;
6765 end if;
6766
6767 Set_Etype (N, Base_Type (Typ));
6768 Generate_Reference (T, N, ' ');
6769
6770 -- Skip remaining processing if already set to Any_Type
6771
6772 if T = Any_Type then
6773 return;
6774 end if;
6775
6776 -- Deal with other error cases
6777
6778 if T = Any_String or else
6779 T = Any_Composite or else
6780 T = Any_Character
6781 then
6782 if T = Any_Character then
6783 Ambiguous_Character (L);
6784 else
6785 Error_Msg_N ("ambiguous operands for comparison", N);
6786 end if;
6787
6788 Set_Etype (N, Any_Type);
6789 return;
6790 end if;
6791
6792 -- Resolve the operands if types OK
6793
6794 Resolve (L, T);
6795 Resolve (R, T);
6796 Check_Unset_Reference (L);
6797 Check_Unset_Reference (R);
6798 Generate_Operator_Reference (N, T);
6799 Check_Low_Bound_Tested (N);
6800
6801 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6802 -- types or array types except String.
6803
6804 if Is_Boolean_Type (T) then
6805 Check_SPARK_05_Restriction
6806 ("comparison is not defined on Boolean type", N);
6807
6808 elsif Is_Array_Type (T)
6809 and then Base_Type (T) /= Standard_String
6810 then
6811 Check_SPARK_05_Restriction
6812 ("comparison is not defined on array types other than String", N);
6813 end if;
6814
6815 -- Check comparison on unordered enumeration
6816
6817 if Bad_Unordered_Enumeration_Reference (N, Etype (L)) then
6818 Error_Msg_Sloc := Sloc (Etype (L));
6819 Error_Msg_NE
6820 ("comparison on unordered enumeration type& declared#?U?",
6821 N, Etype (L));
6822 end if;
6823
6824 -- Evaluate the relation (note we do this after the above check since
6825 -- this Eval call may change N to True/False.
6826
6827 Analyze_Dimension (N);
6828 Eval_Relational_Op (N);
6829 end Resolve_Comparison_Op;
6830
6831 -----------------------------------------
6832 -- Resolve_Discrete_Subtype_Indication --
6833 -----------------------------------------
6834
6835 procedure Resolve_Discrete_Subtype_Indication
6836 (N : Node_Id;
6837 Typ : Entity_Id)
6838 is
6839 R : Node_Id;
6840 S : Entity_Id;
6841
6842 begin
6843 Analyze (Subtype_Mark (N));
6844 S := Entity (Subtype_Mark (N));
6845
6846 if Nkind (Constraint (N)) /= N_Range_Constraint then
6847 Error_Msg_N ("expect range constraint for discrete type", N);
6848 Set_Etype (N, Any_Type);
6849
6850 else
6851 R := Range_Expression (Constraint (N));
6852
6853 if R = Error then
6854 return;
6855 end if;
6856
6857 Analyze (R);
6858
6859 if Base_Type (S) /= Base_Type (Typ) then
6860 Error_Msg_NE
6861 ("expect subtype of }", N, First_Subtype (Typ));
6862
6863 -- Rewrite the constraint as a range of Typ
6864 -- to allow compilation to proceed further.
6865
6866 Set_Etype (N, Typ);
6867 Rewrite (Low_Bound (R),
6868 Make_Attribute_Reference (Sloc (Low_Bound (R)),
6869 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
6870 Attribute_Name => Name_First));
6871 Rewrite (High_Bound (R),
6872 Make_Attribute_Reference (Sloc (High_Bound (R)),
6873 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
6874 Attribute_Name => Name_First));
6875
6876 else
6877 Resolve (R, Typ);
6878 Set_Etype (N, Etype (R));
6879
6880 -- Additionally, we must check that the bounds are compatible
6881 -- with the given subtype, which might be different from the
6882 -- type of the context.
6883
6884 Apply_Range_Check (R, S);
6885
6886 -- ??? If the above check statically detects a Constraint_Error
6887 -- it replaces the offending bound(s) of the range R with a
6888 -- Constraint_Error node. When the itype which uses these bounds
6889 -- is frozen the resulting call to Duplicate_Subexpr generates
6890 -- a new temporary for the bounds.
6891
6892 -- Unfortunately there are other itypes that are also made depend
6893 -- on these bounds, so when Duplicate_Subexpr is called they get
6894 -- a forward reference to the newly created temporaries and Gigi
6895 -- aborts on such forward references. This is probably sign of a
6896 -- more fundamental problem somewhere else in either the order of
6897 -- itype freezing or the way certain itypes are constructed.
6898
6899 -- To get around this problem we call Remove_Side_Effects right
6900 -- away if either bounds of R are a Constraint_Error.
6901
6902 declare
6903 L : constant Node_Id := Low_Bound (R);
6904 H : constant Node_Id := High_Bound (R);
6905
6906 begin
6907 if Nkind (L) = N_Raise_Constraint_Error then
6908 Remove_Side_Effects (L);
6909 end if;
6910
6911 if Nkind (H) = N_Raise_Constraint_Error then
6912 Remove_Side_Effects (H);
6913 end if;
6914 end;
6915
6916 Check_Unset_Reference (Low_Bound (R));
6917 Check_Unset_Reference (High_Bound (R));
6918 end if;
6919 end if;
6920 end Resolve_Discrete_Subtype_Indication;
6921
6922 -------------------------
6923 -- Resolve_Entity_Name --
6924 -------------------------
6925
6926 -- Used to resolve identifiers and expanded names
6927
6928 procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id) is
6929 function Is_Assignment_Or_Object_Expression
6930 (Context : Node_Id;
6931 Expr : Node_Id) return Boolean;
6932 -- Determine whether node Context denotes an assignment statement or an
6933 -- object declaration whose expression is node Expr.
6934
6935 ----------------------------------------
6936 -- Is_Assignment_Or_Object_Expression --
6937 ----------------------------------------
6938
6939 function Is_Assignment_Or_Object_Expression
6940 (Context : Node_Id;
6941 Expr : Node_Id) return Boolean
6942 is
6943 begin
6944 if Nkind_In (Context, N_Assignment_Statement,
6945 N_Object_Declaration)
6946 and then Expression (Context) = Expr
6947 then
6948 return True;
6949
6950 -- Check whether a construct that yields a name is the expression of
6951 -- an assignment statement or an object declaration.
6952
6953 elsif (Nkind_In (Context, N_Attribute_Reference,
6954 N_Explicit_Dereference,
6955 N_Indexed_Component,
6956 N_Selected_Component,
6957 N_Slice)
6958 and then Prefix (Context) = Expr)
6959 or else
6960 (Nkind_In (Context, N_Type_Conversion,
6961 N_Unchecked_Type_Conversion)
6962 and then Expression (Context) = Expr)
6963 then
6964 return
6965 Is_Assignment_Or_Object_Expression
6966 (Context => Parent (Context),
6967 Expr => Context);
6968
6969 -- Otherwise the context is not an assignment statement or an object
6970 -- declaration.
6971
6972 else
6973 return False;
6974 end if;
6975 end Is_Assignment_Or_Object_Expression;
6976
6977 -- Local variables
6978
6979 E : constant Entity_Id := Entity (N);
6980 Par : Node_Id;
6981
6982 -- Start of processing for Resolve_Entity_Name
6983
6984 begin
6985 -- If garbage from errors, set to Any_Type and return
6986
6987 if No (E) and then Total_Errors_Detected /= 0 then
6988 Set_Etype (N, Any_Type);
6989 return;
6990 end if;
6991
6992 -- Replace named numbers by corresponding literals. Note that this is
6993 -- the one case where Resolve_Entity_Name must reset the Etype, since
6994 -- it is currently marked as universal.
6995
6996 if Ekind (E) = E_Named_Integer then
6997 Set_Etype (N, Typ);
6998 Eval_Named_Integer (N);
6999
7000 elsif Ekind (E) = E_Named_Real then
7001 Set_Etype (N, Typ);
7002 Eval_Named_Real (N);
7003
7004 -- For enumeration literals, we need to make sure that a proper style
7005 -- check is done, since such literals are overloaded, and thus we did
7006 -- not do a style check during the first phase of analysis.
7007
7008 elsif Ekind (E) = E_Enumeration_Literal then
7009 Set_Entity_With_Checks (N, E);
7010 Eval_Entity_Name (N);
7011
7012 -- Case of (sub)type name appearing in a context where an expression
7013 -- is expected. This is legal if occurrence is a current instance.
7014 -- See RM 8.6 (17/3).
7015
7016 elsif Is_Type (E) then
7017 if Is_Current_Instance (N) then
7018 null;
7019
7020 -- Any other use is an error
7021
7022 else
7023 Error_Msg_N
7024 ("invalid use of subtype mark in expression or call", N);
7025 end if;
7026
7027 -- Check discriminant use if entity is discriminant in current scope,
7028 -- i.e. discriminant of record or concurrent type currently being
7029 -- analyzed. Uses in corresponding body are unrestricted.
7030
7031 elsif Ekind (E) = E_Discriminant
7032 and then Scope (E) = Current_Scope
7033 and then not Has_Completion (Current_Scope)
7034 then
7035 Check_Discriminant_Use (N);
7036
7037 -- A parameterless generic function cannot appear in a context that
7038 -- requires resolution.
7039
7040 elsif Ekind (E) = E_Generic_Function then
7041 Error_Msg_N ("illegal use of generic function", N);
7042
7043 -- In Ada 83 an OUT parameter cannot be read
7044
7045 elsif Ekind (E) = E_Out_Parameter
7046 and then (Nkind (Parent (N)) in N_Op
7047 or else Nkind (Parent (N)) = N_Explicit_Dereference
7048 or else Is_Assignment_Or_Object_Expression
7049 (Context => Parent (N),
7050 Expr => N))
7051 then
7052 if Ada_Version = Ada_83 then
7053 Error_Msg_N ("(Ada 83) illegal reading of out parameter", N);
7054 end if;
7055
7056 -- In all other cases, just do the possible static evaluation
7057
7058 else
7059 -- A deferred constant that appears in an expression must have a
7060 -- completion, unless it has been removed by in-place expansion of
7061 -- an aggregate. A constant that is a renaming does not need
7062 -- initialization.
7063
7064 if Ekind (E) = E_Constant
7065 and then Comes_From_Source (E)
7066 and then No (Constant_Value (E))
7067 and then Is_Frozen (Etype (E))
7068 and then not In_Spec_Expression
7069 and then not Is_Imported (E)
7070 and then Nkind (Parent (E)) /= N_Object_Renaming_Declaration
7071 then
7072 if No_Initialization (Parent (E))
7073 or else (Present (Full_View (E))
7074 and then No_Initialization (Parent (Full_View (E))))
7075 then
7076 null;
7077 else
7078 Error_Msg_N
7079 ("deferred constant is frozen before completion", N);
7080 end if;
7081 end if;
7082
7083 Eval_Entity_Name (N);
7084 end if;
7085
7086 Par := Parent (N);
7087
7088 -- When the entity appears in a parameter association, retrieve the
7089 -- related subprogram call.
7090
7091 if Nkind (Par) = N_Parameter_Association then
7092 Par := Parent (Par);
7093 end if;
7094
7095 if Comes_From_Source (N) then
7096
7097 -- The following checks are only relevant when SPARK_Mode is on as
7098 -- they are not standard Ada legality rules.
7099
7100 if SPARK_Mode = On then
7101
7102 -- An effectively volatile object subject to enabled properties
7103 -- Async_Writers or Effective_Reads must appear in non-interfering
7104 -- context (SPARK RM 7.1.3(12)).
7105
7106 if Is_Object (E)
7107 and then Is_Effectively_Volatile (E)
7108 and then (Async_Writers_Enabled (E)
7109 or else Effective_Reads_Enabled (E))
7110 and then not Is_OK_Volatile_Context (Par, N)
7111 then
7112 SPARK_Msg_N
7113 ("volatile object cannot appear in this context "
7114 & "(SPARK RM 7.1.3(12))", N);
7115 end if;
7116
7117 -- Check for possible elaboration issues with respect to reads of
7118 -- variables. The act of renaming the variable is not considered a
7119 -- read as it simply establishes an alias.
7120
7121 if Ekind (E) = E_Variable
7122 and then Dynamic_Elaboration_Checks
7123 and then Nkind (Par) /= N_Object_Renaming_Declaration
7124 then
7125 Check_Elab_Call (N);
7126 end if;
7127
7128 -- The variable may eventually become a constituent of a single
7129 -- protected/task type. Record the reference now and verify its
7130 -- legality when analyzing the contract of the variable
7131 -- (SPARK RM 9.3).
7132
7133 if Ekind (E) = E_Variable then
7134 Record_Possible_Part_Of_Reference (E, N);
7135 end if;
7136 end if;
7137
7138 -- A Ghost entity must appear in a specific context
7139
7140 if Is_Ghost_Entity (E) then
7141 Check_Ghost_Context (E, N);
7142 end if;
7143 end if;
7144 end Resolve_Entity_Name;
7145
7146 -------------------
7147 -- Resolve_Entry --
7148 -------------------
7149
7150 procedure Resolve_Entry (Entry_Name : Node_Id) is
7151 Loc : constant Source_Ptr := Sloc (Entry_Name);
7152 Nam : Entity_Id;
7153 New_N : Node_Id;
7154 S : Entity_Id;
7155 Tsk : Entity_Id;
7156 E_Name : Node_Id;
7157 Index : Node_Id;
7158
7159 function Actual_Index_Type (E : Entity_Id) return Entity_Id;
7160 -- If the bounds of the entry family being called depend on task
7161 -- discriminants, build a new index subtype where a discriminant is
7162 -- replaced with the value of the discriminant of the target task.
7163 -- The target task is the prefix of the entry name in the call.
7164
7165 -----------------------
7166 -- Actual_Index_Type --
7167 -----------------------
7168
7169 function Actual_Index_Type (E : Entity_Id) return Entity_Id is
7170 Typ : constant Entity_Id := Entry_Index_Type (E);
7171 Tsk : constant Entity_Id := Scope (E);
7172 Lo : constant Node_Id := Type_Low_Bound (Typ);
7173 Hi : constant Node_Id := Type_High_Bound (Typ);
7174 New_T : Entity_Id;
7175
7176 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id;
7177 -- If the bound is given by a discriminant, replace with a reference
7178 -- to the discriminant of the same name in the target task. If the
7179 -- entry name is the target of a requeue statement and the entry is
7180 -- in the current protected object, the bound to be used is the
7181 -- discriminal of the object (see Apply_Range_Checks for details of
7182 -- the transformation).
7183
7184 -----------------------------
7185 -- Actual_Discriminant_Ref --
7186 -----------------------------
7187
7188 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id is
7189 Typ : constant Entity_Id := Etype (Bound);
7190 Ref : Node_Id;
7191
7192 begin
7193 Remove_Side_Effects (Bound);
7194
7195 if not Is_Entity_Name (Bound)
7196 or else Ekind (Entity (Bound)) /= E_Discriminant
7197 then
7198 return Bound;
7199
7200 elsif Is_Protected_Type (Tsk)
7201 and then In_Open_Scopes (Tsk)
7202 and then Nkind (Parent (Entry_Name)) = N_Requeue_Statement
7203 then
7204 -- Note: here Bound denotes a discriminant of the corresponding
7205 -- record type tskV, whose discriminal is a formal of the
7206 -- init-proc tskVIP. What we want is the body discriminal,
7207 -- which is associated to the discriminant of the original
7208 -- concurrent type tsk.
7209
7210 return New_Occurrence_Of
7211 (Find_Body_Discriminal (Entity (Bound)), Loc);
7212
7213 else
7214 Ref :=
7215 Make_Selected_Component (Loc,
7216 Prefix => New_Copy_Tree (Prefix (Prefix (Entry_Name))),
7217 Selector_Name => New_Occurrence_Of (Entity (Bound), Loc));
7218 Analyze (Ref);
7219 Resolve (Ref, Typ);
7220 return Ref;
7221 end if;
7222 end Actual_Discriminant_Ref;
7223
7224 -- Start of processing for Actual_Index_Type
7225
7226 begin
7227 if not Has_Discriminants (Tsk)
7228 or else (not Is_Entity_Name (Lo) and then not Is_Entity_Name (Hi))
7229 then
7230 return Entry_Index_Type (E);
7231
7232 else
7233 New_T := Create_Itype (Ekind (Typ), Parent (Entry_Name));
7234 Set_Etype (New_T, Base_Type (Typ));
7235 Set_Size_Info (New_T, Typ);
7236 Set_RM_Size (New_T, RM_Size (Typ));
7237 Set_Scalar_Range (New_T,
7238 Make_Range (Sloc (Entry_Name),
7239 Low_Bound => Actual_Discriminant_Ref (Lo),
7240 High_Bound => Actual_Discriminant_Ref (Hi)));
7241
7242 return New_T;
7243 end if;
7244 end Actual_Index_Type;
7245
7246 -- Start of processing for Resolve_Entry
7247
7248 begin
7249 -- Find name of entry being called, and resolve prefix of name with its
7250 -- own type. The prefix can be overloaded, and the name and signature of
7251 -- the entry must be taken into account.
7252
7253 if Nkind (Entry_Name) = N_Indexed_Component then
7254
7255 -- Case of dealing with entry family within the current tasks
7256
7257 E_Name := Prefix (Entry_Name);
7258
7259 else
7260 E_Name := Entry_Name;
7261 end if;
7262
7263 if Is_Entity_Name (E_Name) then
7264
7265 -- Entry call to an entry (or entry family) in the current task. This
7266 -- is legal even though the task will deadlock. Rewrite as call to
7267 -- current task.
7268
7269 -- This can also be a call to an entry in an enclosing task. If this
7270 -- is a single task, we have to retrieve its name, because the scope
7271 -- of the entry is the task type, not the object. If the enclosing
7272 -- task is a task type, the identity of the task is given by its own
7273 -- self variable.
7274
7275 -- Finally this can be a requeue on an entry of the same task or
7276 -- protected object.
7277
7278 S := Scope (Entity (E_Name));
7279
7280 for J in reverse 0 .. Scope_Stack.Last loop
7281 if Is_Task_Type (Scope_Stack.Table (J).Entity)
7282 and then not Comes_From_Source (S)
7283 then
7284 -- S is an enclosing task or protected object. The concurrent
7285 -- declaration has been converted into a type declaration, and
7286 -- the object itself has an object declaration that follows
7287 -- the type in the same declarative part.
7288
7289 Tsk := Next_Entity (S);
7290 while Etype (Tsk) /= S loop
7291 Next_Entity (Tsk);
7292 end loop;
7293
7294 S := Tsk;
7295 exit;
7296
7297 elsif S = Scope_Stack.Table (J).Entity then
7298
7299 -- Call to current task. Will be transformed into call to Self
7300
7301 exit;
7302
7303 end if;
7304 end loop;
7305
7306 New_N :=
7307 Make_Selected_Component (Loc,
7308 Prefix => New_Occurrence_Of (S, Loc),
7309 Selector_Name =>
7310 New_Occurrence_Of (Entity (E_Name), Loc));
7311 Rewrite (E_Name, New_N);
7312 Analyze (E_Name);
7313
7314 elsif Nkind (Entry_Name) = N_Selected_Component
7315 and then Is_Overloaded (Prefix (Entry_Name))
7316 then
7317 -- Use the entry name (which must be unique at this point) to find
7318 -- the prefix that returns the corresponding task/protected type.
7319
7320 declare
7321 Pref : constant Node_Id := Prefix (Entry_Name);
7322 Ent : constant Entity_Id := Entity (Selector_Name (Entry_Name));
7323 I : Interp_Index;
7324 It : Interp;
7325
7326 begin
7327 Get_First_Interp (Pref, I, It);
7328 while Present (It.Typ) loop
7329 if Scope (Ent) = It.Typ then
7330 Set_Etype (Pref, It.Typ);
7331 exit;
7332 end if;
7333
7334 Get_Next_Interp (I, It);
7335 end loop;
7336 end;
7337 end if;
7338
7339 if Nkind (Entry_Name) = N_Selected_Component then
7340 Resolve (Prefix (Entry_Name));
7341
7342 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
7343 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
7344 Resolve (Prefix (Prefix (Entry_Name)));
7345 Index := First (Expressions (Entry_Name));
7346 Resolve (Index, Entry_Index_Type (Nam));
7347
7348 -- Up to this point the expression could have been the actual in a
7349 -- simple entry call, and be given by a named association.
7350
7351 if Nkind (Index) = N_Parameter_Association then
7352 Error_Msg_N ("expect expression for entry index", Index);
7353 else
7354 Apply_Range_Check (Index, Actual_Index_Type (Nam));
7355 end if;
7356 end if;
7357 end Resolve_Entry;
7358
7359 ------------------------
7360 -- Resolve_Entry_Call --
7361 ------------------------
7362
7363 procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id) is
7364 Entry_Name : constant Node_Id := Name (N);
7365 Loc : constant Source_Ptr := Sloc (Entry_Name);
7366 Actuals : List_Id;
7367 First_Named : Node_Id;
7368 Nam : Entity_Id;
7369 Norm_OK : Boolean;
7370 Obj : Node_Id;
7371 Was_Over : Boolean;
7372
7373 begin
7374 -- We kill all checks here, because it does not seem worth the effort to
7375 -- do anything better, an entry call is a big operation.
7376
7377 Kill_All_Checks;
7378
7379 -- Processing of the name is similar for entry calls and protected
7380 -- operation calls. Once the entity is determined, we can complete
7381 -- the resolution of the actuals.
7382
7383 -- The selector may be overloaded, in the case of a protected object
7384 -- with overloaded functions. The type of the context is used for
7385 -- resolution.
7386
7387 if Nkind (Entry_Name) = N_Selected_Component
7388 and then Is_Overloaded (Selector_Name (Entry_Name))
7389 and then Typ /= Standard_Void_Type
7390 then
7391 declare
7392 I : Interp_Index;
7393 It : Interp;
7394
7395 begin
7396 Get_First_Interp (Selector_Name (Entry_Name), I, It);
7397 while Present (It.Typ) loop
7398 if Covers (Typ, It.Typ) then
7399 Set_Entity (Selector_Name (Entry_Name), It.Nam);
7400 Set_Etype (Entry_Name, It.Typ);
7401
7402 Generate_Reference (It.Typ, N, ' ');
7403 end if;
7404
7405 Get_Next_Interp (I, It);
7406 end loop;
7407 end;
7408 end if;
7409
7410 Resolve_Entry (Entry_Name);
7411
7412 if Nkind (Entry_Name) = N_Selected_Component then
7413
7414 -- Simple entry call
7415
7416 Nam := Entity (Selector_Name (Entry_Name));
7417 Obj := Prefix (Entry_Name);
7418 Was_Over := Is_Overloaded (Selector_Name (Entry_Name));
7419
7420 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
7421
7422 -- Call to member of entry family
7423
7424 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
7425 Obj := Prefix (Prefix (Entry_Name));
7426 Was_Over := Is_Overloaded (Selector_Name (Prefix (Entry_Name)));
7427 end if;
7428
7429 -- We cannot in general check the maximum depth of protected entry calls
7430 -- at compile time. But we can tell that any protected entry call at all
7431 -- violates a specified nesting depth of zero.
7432
7433 if Is_Protected_Type (Scope (Nam)) then
7434 Check_Restriction (Max_Entry_Queue_Length, N);
7435 end if;
7436
7437 -- Use context type to disambiguate a protected function that can be
7438 -- called without actuals and that returns an array type, and where the
7439 -- argument list may be an indexing of the returned value.
7440
7441 if Ekind (Nam) = E_Function
7442 and then Needs_No_Actuals (Nam)
7443 and then Present (Parameter_Associations (N))
7444 and then
7445 ((Is_Array_Type (Etype (Nam))
7446 and then Covers (Typ, Component_Type (Etype (Nam))))
7447
7448 or else (Is_Access_Type (Etype (Nam))
7449 and then Is_Array_Type (Designated_Type (Etype (Nam)))
7450 and then
7451 Covers
7452 (Typ,
7453 Component_Type (Designated_Type (Etype (Nam))))))
7454 then
7455 declare
7456 Index_Node : Node_Id;
7457
7458 begin
7459 Index_Node :=
7460 Make_Indexed_Component (Loc,
7461 Prefix =>
7462 Make_Function_Call (Loc, Name => Relocate_Node (Entry_Name)),
7463 Expressions => Parameter_Associations (N));
7464
7465 -- Since we are correcting a node classification error made by the
7466 -- parser, we call Replace rather than Rewrite.
7467
7468 Replace (N, Index_Node);
7469 Set_Etype (Prefix (N), Etype (Nam));
7470 Set_Etype (N, Typ);
7471 Resolve_Indexed_Component (N, Typ);
7472 return;
7473 end;
7474 end if;
7475
7476 if Ekind_In (Nam, E_Entry, E_Entry_Family)
7477 and then Present (Contract_Wrapper (Nam))
7478 and then Current_Scope /= Contract_Wrapper (Nam)
7479 then
7480
7481 -- Note the entity being called before rewriting the call, so that
7482 -- it appears used at this point.
7483
7484 Generate_Reference (Nam, Entry_Name, 'r');
7485
7486 -- Rewrite as call to the precondition wrapper, adding the task
7487 -- object to the list of actuals. If the call is to a member of an
7488 -- entry family, include the index as well.
7489
7490 declare
7491 New_Call : Node_Id;
7492 New_Actuals : List_Id;
7493
7494 begin
7495 New_Actuals := New_List (Obj);
7496
7497 if Nkind (Entry_Name) = N_Indexed_Component then
7498 Append_To (New_Actuals,
7499 New_Copy_Tree (First (Expressions (Entry_Name))));
7500 end if;
7501
7502 Append_List (Parameter_Associations (N), New_Actuals);
7503 New_Call :=
7504 Make_Procedure_Call_Statement (Loc,
7505 Name =>
7506 New_Occurrence_Of (Contract_Wrapper (Nam), Loc),
7507 Parameter_Associations => New_Actuals);
7508 Rewrite (N, New_Call);
7509
7510 -- Preanalyze and resolve new call. Current procedure is called
7511 -- from Resolve_Call, after which expansion will take place.
7512
7513 Preanalyze_And_Resolve (N);
7514 return;
7515 end;
7516 end if;
7517
7518 -- The operation name may have been overloaded. Order the actuals
7519 -- according to the formals of the resolved entity, and set the return
7520 -- type to that of the operation.
7521
7522 if Was_Over then
7523 Normalize_Actuals (N, Nam, False, Norm_OK);
7524 pragma Assert (Norm_OK);
7525 Set_Etype (N, Etype (Nam));
7526
7527 -- Reset the Is_Overloaded flag, since resolution is now completed
7528
7529 -- Simple entry call
7530
7531 if Nkind (Entry_Name) = N_Selected_Component then
7532 Set_Is_Overloaded (Selector_Name (Entry_Name), False);
7533
7534 -- Call to a member of an entry family
7535
7536 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
7537 Set_Is_Overloaded (Selector_Name (Prefix (Entry_Name)), False);
7538 end if;
7539 end if;
7540
7541 Resolve_Actuals (N, Nam);
7542 Check_Internal_Protected_Use (N, Nam);
7543
7544 -- Create a call reference to the entry
7545
7546 Generate_Reference (Nam, Entry_Name, 's');
7547
7548 if Ekind_In (Nam, E_Entry, E_Entry_Family) then
7549 Check_Potentially_Blocking_Operation (N);
7550 end if;
7551
7552 -- Verify that a procedure call cannot masquerade as an entry
7553 -- call where an entry call is expected.
7554
7555 if Ekind (Nam) = E_Procedure then
7556 if Nkind (Parent (N)) = N_Entry_Call_Alternative
7557 and then N = Entry_Call_Statement (Parent (N))
7558 then
7559 Error_Msg_N ("entry call required in select statement", N);
7560
7561 elsif Nkind (Parent (N)) = N_Triggering_Alternative
7562 and then N = Triggering_Statement (Parent (N))
7563 then
7564 Error_Msg_N ("triggering statement cannot be procedure call", N);
7565
7566 elsif Ekind (Scope (Nam)) = E_Task_Type
7567 and then not In_Open_Scopes (Scope (Nam))
7568 then
7569 Error_Msg_N ("task has no entry with this name", Entry_Name);
7570 end if;
7571 end if;
7572
7573 -- After resolution, entry calls and protected procedure calls are
7574 -- changed into entry calls, for expansion. The structure of the node
7575 -- does not change, so it can safely be done in place. Protected
7576 -- function calls must keep their structure because they are
7577 -- subexpressions.
7578
7579 if Ekind (Nam) /= E_Function then
7580
7581 -- A protected operation that is not a function may modify the
7582 -- corresponding object, and cannot apply to a constant. If this
7583 -- is an internal call, the prefix is the type itself.
7584
7585 if Is_Protected_Type (Scope (Nam))
7586 and then not Is_Variable (Obj)
7587 and then (not Is_Entity_Name (Obj)
7588 or else not Is_Type (Entity (Obj)))
7589 then
7590 Error_Msg_N
7591 ("prefix of protected procedure or entry call must be variable",
7592 Entry_Name);
7593 end if;
7594
7595 Actuals := Parameter_Associations (N);
7596 First_Named := First_Named_Actual (N);
7597
7598 Rewrite (N,
7599 Make_Entry_Call_Statement (Loc,
7600 Name => Entry_Name,
7601 Parameter_Associations => Actuals));
7602
7603 Set_First_Named_Actual (N, First_Named);
7604 Set_Analyzed (N, True);
7605
7606 -- Protected functions can return on the secondary stack, in which
7607 -- case we must trigger the transient scope mechanism.
7608
7609 elsif Expander_Active
7610 and then Requires_Transient_Scope (Etype (Nam))
7611 then
7612 Establish_Transient_Scope (N, Sec_Stack => True);
7613 end if;
7614 end Resolve_Entry_Call;
7615
7616 -------------------------
7617 -- Resolve_Equality_Op --
7618 -------------------------
7619
7620 -- Both arguments must have the same type, and the boolean context does
7621 -- not participate in the resolution. The first pass verifies that the
7622 -- interpretation is not ambiguous, and the type of the left argument is
7623 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7624 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7625 -- though they carry a single (universal) type. Diagnose this case here.
7626
7627 procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id) is
7628 L : constant Node_Id := Left_Opnd (N);
7629 R : constant Node_Id := Right_Opnd (N);
7630 T : Entity_Id := Find_Unique_Type (L, R);
7631
7632 procedure Check_If_Expression (Cond : Node_Id);
7633 -- The resolution rule for if expressions requires that each such must
7634 -- have a unique type. This means that if several dependent expressions
7635 -- are of a non-null anonymous access type, and the context does not
7636 -- impose an expected type (as can be the case in an equality operation)
7637 -- the expression must be rejected.
7638
7639 procedure Explain_Redundancy (N : Node_Id);
7640 -- Attempt to explain the nature of a redundant comparison with True. If
7641 -- the expression N is too complex, this routine issues a general error
7642 -- message.
7643
7644 function Find_Unique_Access_Type return Entity_Id;
7645 -- In the case of allocators and access attributes, the context must
7646 -- provide an indication of the specific access type to be used. If
7647 -- one operand is of such a "generic" access type, check whether there
7648 -- is a specific visible access type that has the same designated type.
7649 -- This is semantically dubious, and of no interest to any real code,
7650 -- but c48008a makes it all worthwhile.
7651
7652 -------------------------
7653 -- Check_If_Expression --
7654 -------------------------
7655
7656 procedure Check_If_Expression (Cond : Node_Id) is
7657 Then_Expr : Node_Id;
7658 Else_Expr : Node_Id;
7659
7660 begin
7661 if Nkind (Cond) = N_If_Expression then
7662 Then_Expr := Next (First (Expressions (Cond)));
7663 Else_Expr := Next (Then_Expr);
7664
7665 if Nkind (Then_Expr) /= N_Null
7666 and then Nkind (Else_Expr) /= N_Null
7667 then
7668 Error_Msg_N ("cannot determine type of if expression", Cond);
7669 end if;
7670 end if;
7671 end Check_If_Expression;
7672
7673 ------------------------
7674 -- Explain_Redundancy --
7675 ------------------------
7676
7677 procedure Explain_Redundancy (N : Node_Id) is
7678 Error : Name_Id;
7679 Val : Node_Id;
7680 Val_Id : Entity_Id;
7681
7682 begin
7683 Val := N;
7684
7685 -- Strip the operand down to an entity
7686
7687 loop
7688 if Nkind (Val) = N_Selected_Component then
7689 Val := Selector_Name (Val);
7690 else
7691 exit;
7692 end if;
7693 end loop;
7694
7695 -- The construct denotes an entity
7696
7697 if Is_Entity_Name (Val) and then Present (Entity (Val)) then
7698 Val_Id := Entity (Val);
7699
7700 -- Do not generate an error message when the comparison is done
7701 -- against the enumeration literal Standard.True.
7702
7703 if Ekind (Val_Id) /= E_Enumeration_Literal then
7704
7705 -- Build a customized error message
7706
7707 Name_Len := 0;
7708 Add_Str_To_Name_Buffer ("?r?");
7709
7710 if Ekind (Val_Id) = E_Component then
7711 Add_Str_To_Name_Buffer ("component ");
7712
7713 elsif Ekind (Val_Id) = E_Constant then
7714 Add_Str_To_Name_Buffer ("constant ");
7715
7716 elsif Ekind (Val_Id) = E_Discriminant then
7717 Add_Str_To_Name_Buffer ("discriminant ");
7718
7719 elsif Is_Formal (Val_Id) then
7720 Add_Str_To_Name_Buffer ("parameter ");
7721
7722 elsif Ekind (Val_Id) = E_Variable then
7723 Add_Str_To_Name_Buffer ("variable ");
7724 end if;
7725
7726 Add_Str_To_Name_Buffer ("& is always True!");
7727 Error := Name_Find;
7728
7729 Error_Msg_NE (Get_Name_String (Error), Val, Val_Id);
7730 end if;
7731
7732 -- The construct is too complex to disect, issue a general message
7733
7734 else
7735 Error_Msg_N ("?r?expression is always True!", Val);
7736 end if;
7737 end Explain_Redundancy;
7738
7739 -----------------------------
7740 -- Find_Unique_Access_Type --
7741 -----------------------------
7742
7743 function Find_Unique_Access_Type return Entity_Id is
7744 Acc : Entity_Id;
7745 E : Entity_Id;
7746 S : Entity_Id;
7747
7748 begin
7749 if Ekind_In (Etype (R), E_Allocator_Type,
7750 E_Access_Attribute_Type)
7751 then
7752 Acc := Designated_Type (Etype (R));
7753
7754 elsif Ekind_In (Etype (L), E_Allocator_Type,
7755 E_Access_Attribute_Type)
7756 then
7757 Acc := Designated_Type (Etype (L));
7758 else
7759 return Empty;
7760 end if;
7761
7762 S := Current_Scope;
7763 while S /= Standard_Standard loop
7764 E := First_Entity (S);
7765 while Present (E) loop
7766 if Is_Type (E)
7767 and then Is_Access_Type (E)
7768 and then Ekind (E) /= E_Allocator_Type
7769 and then Designated_Type (E) = Base_Type (Acc)
7770 then
7771 return E;
7772 end if;
7773
7774 Next_Entity (E);
7775 end loop;
7776
7777 S := Scope (S);
7778 end loop;
7779
7780 return Empty;
7781 end Find_Unique_Access_Type;
7782
7783 -- Start of processing for Resolve_Equality_Op
7784
7785 begin
7786 Set_Etype (N, Base_Type (Typ));
7787 Generate_Reference (T, N, ' ');
7788
7789 if T = Any_Fixed then
7790 T := Unique_Fixed_Point_Type (L);
7791 end if;
7792
7793 if T /= Any_Type then
7794 if T = Any_String or else
7795 T = Any_Composite or else
7796 T = Any_Character
7797 then
7798 if T = Any_Character then
7799 Ambiguous_Character (L);
7800 else
7801 Error_Msg_N ("ambiguous operands for equality", N);
7802 end if;
7803
7804 Set_Etype (N, Any_Type);
7805 return;
7806
7807 elsif T = Any_Access
7808 or else Ekind_In (T, E_Allocator_Type, E_Access_Attribute_Type)
7809 then
7810 T := Find_Unique_Access_Type;
7811
7812 if No (T) then
7813 Error_Msg_N ("ambiguous operands for equality", N);
7814 Set_Etype (N, Any_Type);
7815 return;
7816 end if;
7817
7818 -- If expressions must have a single type, and if the context does
7819 -- not impose one the dependent expressions cannot be anonymous
7820 -- access types.
7821
7822 -- Why no similar processing for case expressions???
7823
7824 elsif Ada_Version >= Ada_2012
7825 and then Ekind_In (Etype (L), E_Anonymous_Access_Type,
7826 E_Anonymous_Access_Subprogram_Type)
7827 and then Ekind_In (Etype (R), E_Anonymous_Access_Type,
7828 E_Anonymous_Access_Subprogram_Type)
7829 then
7830 Check_If_Expression (L);
7831 Check_If_Expression (R);
7832 end if;
7833
7834 Resolve (L, T);
7835 Resolve (R, T);
7836
7837 -- In SPARK, equality operators = and /= for array types other than
7838 -- String are only defined when, for each index position, the
7839 -- operands have equal static bounds.
7840
7841 if Is_Array_Type (T) then
7842
7843 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7844 -- operation if not needed.
7845
7846 if Restriction_Check_Required (SPARK_05)
7847 and then Base_Type (T) /= Standard_String
7848 and then Base_Type (Etype (L)) = Base_Type (Etype (R))
7849 and then Etype (L) /= Any_Composite -- or else L in error
7850 and then Etype (R) /= Any_Composite -- or else R in error
7851 and then not Matching_Static_Array_Bounds (Etype (L), Etype (R))
7852 then
7853 Check_SPARK_05_Restriction
7854 ("array types should have matching static bounds", N);
7855 end if;
7856 end if;
7857
7858 -- If the unique type is a class-wide type then it will be expanded
7859 -- into a dispatching call to the predefined primitive. Therefore we
7860 -- check here for potential violation of such restriction.
7861
7862 if Is_Class_Wide_Type (T) then
7863 Check_Restriction (No_Dispatching_Calls, N);
7864 end if;
7865
7866 if Warn_On_Redundant_Constructs
7867 and then Comes_From_Source (N)
7868 and then Comes_From_Source (R)
7869 and then Is_Entity_Name (R)
7870 and then Entity (R) = Standard_True
7871 then
7872 Error_Msg_N -- CODEFIX
7873 ("?r?comparison with True is redundant!", N);
7874 Explain_Redundancy (Original_Node (R));
7875 end if;
7876
7877 Check_Unset_Reference (L);
7878 Check_Unset_Reference (R);
7879 Generate_Operator_Reference (N, T);
7880 Check_Low_Bound_Tested (N);
7881
7882 -- If this is an inequality, it may be the implicit inequality
7883 -- created for a user-defined operation, in which case the corres-
7884 -- ponding equality operation is not intrinsic, and the operation
7885 -- cannot be constant-folded. Else fold.
7886
7887 if Nkind (N) = N_Op_Eq
7888 or else Comes_From_Source (Entity (N))
7889 or else Ekind (Entity (N)) = E_Operator
7890 or else Is_Intrinsic_Subprogram
7891 (Corresponding_Equality (Entity (N)))
7892 then
7893 Analyze_Dimension (N);
7894 Eval_Relational_Op (N);
7895
7896 elsif Nkind (N) = N_Op_Ne
7897 and then Is_Abstract_Subprogram (Entity (N))
7898 then
7899 Error_Msg_NE ("cannot call abstract subprogram &!", N, Entity (N));
7900 end if;
7901
7902 -- Ada 2005: If one operand is an anonymous access type, convert the
7903 -- other operand to it, to ensure that the underlying types match in
7904 -- the back-end. Same for access_to_subprogram, and the conversion
7905 -- verifies that the types are subtype conformant.
7906
7907 -- We apply the same conversion in the case one of the operands is a
7908 -- private subtype of the type of the other.
7909
7910 -- Why the Expander_Active test here ???
7911
7912 if Expander_Active
7913 and then
7914 (Ekind_In (T, E_Anonymous_Access_Type,
7915 E_Anonymous_Access_Subprogram_Type)
7916 or else Is_Private_Type (T))
7917 then
7918 if Etype (L) /= T then
7919 Rewrite (L,
7920 Make_Unchecked_Type_Conversion (Sloc (L),
7921 Subtype_Mark => New_Occurrence_Of (T, Sloc (L)),
7922 Expression => Relocate_Node (L)));
7923 Analyze_And_Resolve (L, T);
7924 end if;
7925
7926 if (Etype (R)) /= T then
7927 Rewrite (R,
7928 Make_Unchecked_Type_Conversion (Sloc (R),
7929 Subtype_Mark => New_Occurrence_Of (Etype (L), Sloc (R)),
7930 Expression => Relocate_Node (R)));
7931 Analyze_And_Resolve (R, T);
7932 end if;
7933 end if;
7934 end if;
7935 end Resolve_Equality_Op;
7936
7937 ----------------------------------
7938 -- Resolve_Explicit_Dereference --
7939 ----------------------------------
7940
7941 procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id) is
7942 Loc : constant Source_Ptr := Sloc (N);
7943 New_N : Node_Id;
7944 P : constant Node_Id := Prefix (N);
7945
7946 P_Typ : Entity_Id;
7947 -- The candidate prefix type, if overloaded
7948
7949 I : Interp_Index;
7950 It : Interp;
7951
7952 begin
7953 Check_Fully_Declared_Prefix (Typ, P);
7954 P_Typ := Empty;
7955
7956 -- A useful optimization: check whether the dereference denotes an
7957 -- element of a container, and if so rewrite it as a call to the
7958 -- corresponding Element function.
7959
7960 -- Disabled for now, on advice of ARG. A more restricted form of the
7961 -- predicate might be acceptable ???
7962
7963 -- if Is_Container_Element (N) then
7964 -- return;
7965 -- end if;
7966
7967 if Is_Overloaded (P) then
7968
7969 -- Use the context type to select the prefix that has the correct
7970 -- designated type. Keep the first match, which will be the inner-
7971 -- most.
7972
7973 Get_First_Interp (P, I, It);
7974
7975 while Present (It.Typ) loop
7976 if Is_Access_Type (It.Typ)
7977 and then Covers (Typ, Designated_Type (It.Typ))
7978 then
7979 if No (P_Typ) then
7980 P_Typ := It.Typ;
7981 end if;
7982
7983 -- Remove access types that do not match, but preserve access
7984 -- to subprogram interpretations, in case a further dereference
7985 -- is needed (see below).
7986
7987 elsif Ekind (It.Typ) /= E_Access_Subprogram_Type then
7988 Remove_Interp (I);
7989 end if;
7990
7991 Get_Next_Interp (I, It);
7992 end loop;
7993
7994 if Present (P_Typ) then
7995 Resolve (P, P_Typ);
7996 Set_Etype (N, Designated_Type (P_Typ));
7997
7998 else
7999 -- If no interpretation covers the designated type of the prefix,
8000 -- this is the pathological case where not all implementations of
8001 -- the prefix allow the interpretation of the node as a call. Now
8002 -- that the expected type is known, Remove other interpretations
8003 -- from prefix, rewrite it as a call, and resolve again, so that
8004 -- the proper call node is generated.
8005
8006 Get_First_Interp (P, I, It);
8007 while Present (It.Typ) loop
8008 if Ekind (It.Typ) /= E_Access_Subprogram_Type then
8009 Remove_Interp (I);
8010 end if;
8011
8012 Get_Next_Interp (I, It);
8013 end loop;
8014
8015 New_N :=
8016 Make_Function_Call (Loc,
8017 Name =>
8018 Make_Explicit_Dereference (Loc,
8019 Prefix => P),
8020 Parameter_Associations => New_List);
8021
8022 Save_Interps (N, New_N);
8023 Rewrite (N, New_N);
8024 Analyze_And_Resolve (N, Typ);
8025 return;
8026 end if;
8027
8028 -- If not overloaded, resolve P with its own type
8029
8030 else
8031 Resolve (P);
8032 end if;
8033
8034 -- If the prefix might be null, add an access check
8035
8036 if Is_Access_Type (Etype (P))
8037 and then not Can_Never_Be_Null (Etype (P))
8038 then
8039 Apply_Access_Check (N);
8040 end if;
8041
8042 -- If the designated type is a packed unconstrained array type, and the
8043 -- explicit dereference is not in the context of an attribute reference,
8044 -- then we must compute and set the actual subtype, since it is needed
8045 -- by Gigi. The reason we exclude the attribute case is that this is
8046 -- handled fine by Gigi, and in fact we use such attributes to build the
8047 -- actual subtype. We also exclude generated code (which builds actual
8048 -- subtypes directly if they are needed).
8049
8050 if Is_Array_Type (Etype (N))
8051 and then Is_Packed (Etype (N))
8052 and then not Is_Constrained (Etype (N))
8053 and then Nkind (Parent (N)) /= N_Attribute_Reference
8054 and then Comes_From_Source (N)
8055 then
8056 Set_Etype (N, Get_Actual_Subtype (N));
8057 end if;
8058
8059 Analyze_Dimension (N);
8060
8061 -- Note: No Eval processing is required for an explicit dereference,
8062 -- because such a name can never be static.
8063
8064 end Resolve_Explicit_Dereference;
8065
8066 -------------------------------------
8067 -- Resolve_Expression_With_Actions --
8068 -------------------------------------
8069
8070 procedure Resolve_Expression_With_Actions (N : Node_Id; Typ : Entity_Id) is
8071 begin
8072 Set_Etype (N, Typ);
8073
8074 -- If N has no actions, and its expression has been constant folded,
8075 -- then rewrite N as just its expression. Note, we can't do this in
8076 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8077 -- Expression (N) to be expanded again.
8078
8079 if Is_Empty_List (Actions (N))
8080 and then Compile_Time_Known_Value (Expression (N))
8081 then
8082 Rewrite (N, Expression (N));
8083 end if;
8084 end Resolve_Expression_With_Actions;
8085
8086 ----------------------------------
8087 -- Resolve_Generalized_Indexing --
8088 ----------------------------------
8089
8090 procedure Resolve_Generalized_Indexing (N : Node_Id; Typ : Entity_Id) is
8091 Indexing : constant Node_Id := Generalized_Indexing (N);
8092 Call : Node_Id;
8093 Indexes : List_Id;
8094 Pref : Node_Id;
8095
8096 begin
8097 -- In ASIS mode, propagate the information about the indexes back to
8098 -- to the original indexing node. The generalized indexing is either
8099 -- a function call, or a dereference of one. The actuals include the
8100 -- prefix of the original node, which is the container expression.
8101
8102 if ASIS_Mode then
8103 Resolve (Indexing, Typ);
8104 Set_Etype (N, Etype (Indexing));
8105 Set_Is_Overloaded (N, False);
8106
8107 Call := Indexing;
8108 while Nkind_In (Call, N_Explicit_Dereference, N_Selected_Component)
8109 loop
8110 Call := Prefix (Call);
8111 end loop;
8112
8113 if Nkind (Call) = N_Function_Call then
8114 Indexes := Parameter_Associations (Call);
8115 Pref := Remove_Head (Indexes);
8116 Set_Expressions (N, Indexes);
8117
8118 -- If expression is to be reanalyzed, reset Generalized_Indexing
8119 -- to recreate call node, as is the case when the expression is
8120 -- part of an expression function.
8121
8122 if In_Spec_Expression then
8123 Set_Generalized_Indexing (N, Empty);
8124 end if;
8125
8126 Set_Prefix (N, Pref);
8127 end if;
8128
8129 else
8130 Rewrite (N, Indexing);
8131 Resolve (N, Typ);
8132 end if;
8133 end Resolve_Generalized_Indexing;
8134
8135 ---------------------------
8136 -- Resolve_If_Expression --
8137 ---------------------------
8138
8139 procedure Resolve_If_Expression (N : Node_Id; Typ : Entity_Id) is
8140 Condition : constant Node_Id := First (Expressions (N));
8141 Then_Expr : constant Node_Id := Next (Condition);
8142 Else_Expr : Node_Id := Next (Then_Expr);
8143 Else_Typ : Entity_Id;
8144 Then_Typ : Entity_Id;
8145
8146 begin
8147 Resolve (Condition, Any_Boolean);
8148 Resolve (Then_Expr, Typ);
8149 Then_Typ := Etype (Then_Expr);
8150
8151 -- When the "then" expression is of a scalar subtype different from the
8152 -- result subtype, then insert a conversion to ensure the generation of
8153 -- a constraint check. The same is done for the else part below, again
8154 -- comparing subtypes rather than base types.
8155
8156 if Is_Scalar_Type (Then_Typ)
8157 and then Then_Typ /= Typ
8158 then
8159 Rewrite (Then_Expr, Convert_To (Typ, Then_Expr));
8160 Analyze_And_Resolve (Then_Expr, Typ);
8161 end if;
8162
8163 -- If ELSE expression present, just resolve using the determined type
8164 -- If type is universal, resolve to any member of the class.
8165
8166 if Present (Else_Expr) then
8167 if Typ = Universal_Integer then
8168 Resolve (Else_Expr, Any_Integer);
8169
8170 elsif Typ = Universal_Real then
8171 Resolve (Else_Expr, Any_Real);
8172
8173 else
8174 Resolve (Else_Expr, Typ);
8175 end if;
8176
8177 Else_Typ := Etype (Else_Expr);
8178
8179 if Is_Scalar_Type (Else_Typ) and then Else_Typ /= Typ then
8180 Rewrite (Else_Expr, Convert_To (Typ, Else_Expr));
8181 Analyze_And_Resolve (Else_Expr, Typ);
8182
8183 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8184 -- dynamically tagged must be known statically.
8185
8186 elsif Is_Tagged_Type (Typ) and then not Is_Class_Wide_Type (Typ) then
8187 if Is_Dynamically_Tagged (Then_Expr) /=
8188 Is_Dynamically_Tagged (Else_Expr)
8189 then
8190 Error_Msg_N ("all or none of the dependent expressions "
8191 & "can be dynamically tagged", N);
8192 end if;
8193 end if;
8194
8195 -- If no ELSE expression is present, root type must be Standard.Boolean
8196 -- and we provide a Standard.True result converted to the appropriate
8197 -- Boolean type (in case it is a derived boolean type).
8198
8199 elsif Root_Type (Typ) = Standard_Boolean then
8200 Else_Expr :=
8201 Convert_To (Typ, New_Occurrence_Of (Standard_True, Sloc (N)));
8202 Analyze_And_Resolve (Else_Expr, Typ);
8203 Append_To (Expressions (N), Else_Expr);
8204
8205 else
8206 Error_Msg_N ("can only omit ELSE expression in Boolean case", N);
8207 Append_To (Expressions (N), Error);
8208 end if;
8209
8210 Set_Etype (N, Typ);
8211 Eval_If_Expression (N);
8212 end Resolve_If_Expression;
8213
8214 -------------------------------
8215 -- Resolve_Indexed_Component --
8216 -------------------------------
8217
8218 procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id) is
8219 Name : constant Node_Id := Prefix (N);
8220 Expr : Node_Id;
8221 Array_Type : Entity_Id := Empty; -- to prevent junk warning
8222 Index : Node_Id;
8223
8224 begin
8225 if Present (Generalized_Indexing (N)) then
8226 Resolve_Generalized_Indexing (N, Typ);
8227 return;
8228 end if;
8229
8230 if Is_Overloaded (Name) then
8231
8232 -- Use the context type to select the prefix that yields the correct
8233 -- component type.
8234
8235 declare
8236 I : Interp_Index;
8237 It : Interp;
8238 I1 : Interp_Index := 0;
8239 P : constant Node_Id := Prefix (N);
8240 Found : Boolean := False;
8241
8242 begin
8243 Get_First_Interp (P, I, It);
8244 while Present (It.Typ) loop
8245 if (Is_Array_Type (It.Typ)
8246 and then Covers (Typ, Component_Type (It.Typ)))
8247 or else (Is_Access_Type (It.Typ)
8248 and then Is_Array_Type (Designated_Type (It.Typ))
8249 and then
8250 Covers
8251 (Typ,
8252 Component_Type (Designated_Type (It.Typ))))
8253 then
8254 if Found then
8255 It := Disambiguate (P, I1, I, Any_Type);
8256
8257 if It = No_Interp then
8258 Error_Msg_N ("ambiguous prefix for indexing", N);
8259 Set_Etype (N, Typ);
8260 return;
8261
8262 else
8263 Found := True;
8264 Array_Type := It.Typ;
8265 I1 := I;
8266 end if;
8267
8268 else
8269 Found := True;
8270 Array_Type := It.Typ;
8271 I1 := I;
8272 end if;
8273 end if;
8274
8275 Get_Next_Interp (I, It);
8276 end loop;
8277 end;
8278
8279 else
8280 Array_Type := Etype (Name);
8281 end if;
8282
8283 Resolve (Name, Array_Type);
8284 Array_Type := Get_Actual_Subtype_If_Available (Name);
8285
8286 -- If prefix is access type, dereference to get real array type.
8287 -- Note: we do not apply an access check because the expander always
8288 -- introduces an explicit dereference, and the check will happen there.
8289
8290 if Is_Access_Type (Array_Type) then
8291 Array_Type := Designated_Type (Array_Type);
8292 end if;
8293
8294 -- If name was overloaded, set component type correctly now
8295 -- If a misplaced call to an entry family (which has no index types)
8296 -- return. Error will be diagnosed from calling context.
8297
8298 if Is_Array_Type (Array_Type) then
8299 Set_Etype (N, Component_Type (Array_Type));
8300 else
8301 return;
8302 end if;
8303
8304 Index := First_Index (Array_Type);
8305 Expr := First (Expressions (N));
8306
8307 -- The prefix may have resolved to a string literal, in which case its
8308 -- etype has a special representation. This is only possible currently
8309 -- if the prefix is a static concatenation, written in functional
8310 -- notation.
8311
8312 if Ekind (Array_Type) = E_String_Literal_Subtype then
8313 Resolve (Expr, Standard_Positive);
8314
8315 else
8316 while Present (Index) and Present (Expr) loop
8317 Resolve (Expr, Etype (Index));
8318 Check_Unset_Reference (Expr);
8319
8320 if Is_Scalar_Type (Etype (Expr)) then
8321 Apply_Scalar_Range_Check (Expr, Etype (Index));
8322 else
8323 Apply_Range_Check (Expr, Get_Actual_Subtype (Index));
8324 end if;
8325
8326 Next_Index (Index);
8327 Next (Expr);
8328 end loop;
8329 end if;
8330
8331 Analyze_Dimension (N);
8332
8333 -- Do not generate the warning on suspicious index if we are analyzing
8334 -- package Ada.Tags; otherwise we will report the warning with the
8335 -- Prims_Ptr field of the dispatch table.
8336
8337 if Scope (Etype (Prefix (N))) = Standard_Standard
8338 or else not
8339 Is_RTU (Cunit_Entity (Get_Source_Unit (Etype (Prefix (N)))),
8340 Ada_Tags)
8341 then
8342 Warn_On_Suspicious_Index (Name, First (Expressions (N)));
8343 Eval_Indexed_Component (N);
8344 end if;
8345
8346 -- If the array type is atomic, and the component is not atomic, then
8347 -- this is worth a warning, since we have a situation where the access
8348 -- to the component may cause extra read/writes of the atomic array
8349 -- object, or partial word accesses, which could be unexpected.
8350
8351 if Nkind (N) = N_Indexed_Component
8352 and then Is_Atomic_Ref_With_Address (N)
8353 and then not (Has_Atomic_Components (Array_Type)
8354 or else (Is_Entity_Name (Prefix (N))
8355 and then Has_Atomic_Components
8356 (Entity (Prefix (N)))))
8357 and then not Is_Atomic (Component_Type (Array_Type))
8358 then
8359 Error_Msg_N
8360 ("??access to non-atomic component of atomic array", Prefix (N));
8361 Error_Msg_N
8362 ("??\may cause unexpected accesses to atomic object", Prefix (N));
8363 end if;
8364 end Resolve_Indexed_Component;
8365
8366 -----------------------------
8367 -- Resolve_Integer_Literal --
8368 -----------------------------
8369
8370 procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id) is
8371 begin
8372 Set_Etype (N, Typ);
8373 Eval_Integer_Literal (N);
8374 end Resolve_Integer_Literal;
8375
8376 --------------------------------
8377 -- Resolve_Intrinsic_Operator --
8378 --------------------------------
8379
8380 procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id) is
8381 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
8382 Op : Entity_Id;
8383 Arg1 : Node_Id;
8384 Arg2 : Node_Id;
8385
8386 function Convert_Operand (Opnd : Node_Id) return Node_Id;
8387 -- If the operand is a literal, it cannot be the expression in a
8388 -- conversion. Use a qualified expression instead.
8389
8390 ---------------------
8391 -- Convert_Operand --
8392 ---------------------
8393
8394 function Convert_Operand (Opnd : Node_Id) return Node_Id is
8395 Loc : constant Source_Ptr := Sloc (Opnd);
8396 Res : Node_Id;
8397
8398 begin
8399 if Nkind_In (Opnd, N_Integer_Literal, N_Real_Literal) then
8400 Res :=
8401 Make_Qualified_Expression (Loc,
8402 Subtype_Mark => New_Occurrence_Of (Btyp, Loc),
8403 Expression => Relocate_Node (Opnd));
8404 Analyze (Res);
8405
8406 else
8407 Res := Unchecked_Convert_To (Btyp, Opnd);
8408 end if;
8409
8410 return Res;
8411 end Convert_Operand;
8412
8413 -- Start of processing for Resolve_Intrinsic_Operator
8414
8415 begin
8416 -- We must preserve the original entity in a generic setting, so that
8417 -- the legality of the operation can be verified in an instance.
8418
8419 if not Expander_Active then
8420 return;
8421 end if;
8422
8423 Op := Entity (N);
8424 while Scope (Op) /= Standard_Standard loop
8425 Op := Homonym (Op);
8426 pragma Assert (Present (Op));
8427 end loop;
8428
8429 Set_Entity (N, Op);
8430 Set_Is_Overloaded (N, False);
8431
8432 -- If the result or operand types are private, rewrite with unchecked
8433 -- conversions on the operands and the result, to expose the proper
8434 -- underlying numeric type.
8435
8436 if Is_Private_Type (Typ)
8437 or else Is_Private_Type (Etype (Left_Opnd (N)))
8438 or else Is_Private_Type (Etype (Right_Opnd (N)))
8439 then
8440 Arg1 := Convert_Operand (Left_Opnd (N));
8441
8442 if Nkind (N) = N_Op_Expon then
8443 Arg2 := Unchecked_Convert_To (Standard_Integer, Right_Opnd (N));
8444 else
8445 Arg2 := Convert_Operand (Right_Opnd (N));
8446 end if;
8447
8448 if Nkind (Arg1) = N_Type_Conversion then
8449 Save_Interps (Left_Opnd (N), Expression (Arg1));
8450 end if;
8451
8452 if Nkind (Arg2) = N_Type_Conversion then
8453 Save_Interps (Right_Opnd (N), Expression (Arg2));
8454 end if;
8455
8456 Set_Left_Opnd (N, Arg1);
8457 Set_Right_Opnd (N, Arg2);
8458
8459 Set_Etype (N, Btyp);
8460 Rewrite (N, Unchecked_Convert_To (Typ, N));
8461 Resolve (N, Typ);
8462
8463 elsif Typ /= Etype (Left_Opnd (N))
8464 or else Typ /= Etype (Right_Opnd (N))
8465 then
8466 -- Add explicit conversion where needed, and save interpretations in
8467 -- case operands are overloaded.
8468
8469 Arg1 := Convert_To (Typ, Left_Opnd (N));
8470 Arg2 := Convert_To (Typ, Right_Opnd (N));
8471
8472 if Nkind (Arg1) = N_Type_Conversion then
8473 Save_Interps (Left_Opnd (N), Expression (Arg1));
8474 else
8475 Save_Interps (Left_Opnd (N), Arg1);
8476 end if;
8477
8478 if Nkind (Arg2) = N_Type_Conversion then
8479 Save_Interps (Right_Opnd (N), Expression (Arg2));
8480 else
8481 Save_Interps (Right_Opnd (N), Arg2);
8482 end if;
8483
8484 Rewrite (Left_Opnd (N), Arg1);
8485 Rewrite (Right_Opnd (N), Arg2);
8486 Analyze (Arg1);
8487 Analyze (Arg2);
8488 Resolve_Arithmetic_Op (N, Typ);
8489
8490 else
8491 Resolve_Arithmetic_Op (N, Typ);
8492 end if;
8493 end Resolve_Intrinsic_Operator;
8494
8495 --------------------------------------
8496 -- Resolve_Intrinsic_Unary_Operator --
8497 --------------------------------------
8498
8499 procedure Resolve_Intrinsic_Unary_Operator
8500 (N : Node_Id;
8501 Typ : Entity_Id)
8502 is
8503 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
8504 Op : Entity_Id;
8505 Arg2 : Node_Id;
8506
8507 begin
8508 Op := Entity (N);
8509 while Scope (Op) /= Standard_Standard loop
8510 Op := Homonym (Op);
8511 pragma Assert (Present (Op));
8512 end loop;
8513
8514 Set_Entity (N, Op);
8515
8516 if Is_Private_Type (Typ) then
8517 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
8518 Save_Interps (Right_Opnd (N), Expression (Arg2));
8519
8520 Set_Right_Opnd (N, Arg2);
8521
8522 Set_Etype (N, Btyp);
8523 Rewrite (N, Unchecked_Convert_To (Typ, N));
8524 Resolve (N, Typ);
8525
8526 else
8527 Resolve_Unary_Op (N, Typ);
8528 end if;
8529 end Resolve_Intrinsic_Unary_Operator;
8530
8531 ------------------------
8532 -- Resolve_Logical_Op --
8533 ------------------------
8534
8535 procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id) is
8536 B_Typ : Entity_Id;
8537
8538 begin
8539 Check_No_Direct_Boolean_Operators (N);
8540
8541 -- Predefined operations on scalar types yield the base type. On the
8542 -- other hand, logical operations on arrays yield the type of the
8543 -- arguments (and the context).
8544
8545 if Is_Array_Type (Typ) then
8546 B_Typ := Typ;
8547 else
8548 B_Typ := Base_Type (Typ);
8549 end if;
8550
8551 -- The following test is required because the operands of the operation
8552 -- may be literals, in which case the resulting type appears to be
8553 -- compatible with a signed integer type, when in fact it is compatible
8554 -- only with modular types. If the context itself is universal, the
8555 -- operation is illegal.
8556
8557 if not Valid_Boolean_Arg (Typ) then
8558 Error_Msg_N ("invalid context for logical operation", N);
8559 Set_Etype (N, Any_Type);
8560 return;
8561
8562 elsif Typ = Any_Modular then
8563 Error_Msg_N
8564 ("no modular type available in this context", N);
8565 Set_Etype (N, Any_Type);
8566 return;
8567
8568 elsif Is_Modular_Integer_Type (Typ)
8569 and then Etype (Left_Opnd (N)) = Universal_Integer
8570 and then Etype (Right_Opnd (N)) = Universal_Integer
8571 then
8572 Check_For_Visible_Operator (N, B_Typ);
8573 end if;
8574
8575 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8576 -- is active and the result type is standard Boolean (do not mess with
8577 -- ops that return a nonstandard Boolean type, because something strange
8578 -- is going on).
8579
8580 -- Note: you might expect this replacement to be done during expansion,
8581 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8582 -- is used, no part of the right operand of an "and" or "or" operator
8583 -- should be executed if the left operand would short-circuit the
8584 -- evaluation of the corresponding "and then" or "or else". If we left
8585 -- the replacement to expansion time, then run-time checks associated
8586 -- with such operands would be evaluated unconditionally, due to being
8587 -- before the condition prior to the rewriting as short-circuit forms
8588 -- during expansion.
8589
8590 if Short_Circuit_And_Or
8591 and then B_Typ = Standard_Boolean
8592 and then Nkind_In (N, N_Op_And, N_Op_Or)
8593 then
8594 -- Mark the corresponding putative SCO operator as truly a logical
8595 -- (and short-circuit) operator.
8596
8597 if Generate_SCO and then Comes_From_Source (N) then
8598 Set_SCO_Logical_Operator (N);
8599 end if;
8600
8601 if Nkind (N) = N_Op_And then
8602 Rewrite (N,
8603 Make_And_Then (Sloc (N),
8604 Left_Opnd => Relocate_Node (Left_Opnd (N)),
8605 Right_Opnd => Relocate_Node (Right_Opnd (N))));
8606 Analyze_And_Resolve (N, B_Typ);
8607
8608 -- Case of OR changed to OR ELSE
8609
8610 else
8611 Rewrite (N,
8612 Make_Or_Else (Sloc (N),
8613 Left_Opnd => Relocate_Node (Left_Opnd (N)),
8614 Right_Opnd => Relocate_Node (Right_Opnd (N))));
8615 Analyze_And_Resolve (N, B_Typ);
8616 end if;
8617
8618 -- Return now, since analysis of the rewritten ops will take care of
8619 -- other reference bookkeeping and expression folding.
8620
8621 return;
8622 end if;
8623
8624 Resolve (Left_Opnd (N), B_Typ);
8625 Resolve (Right_Opnd (N), B_Typ);
8626
8627 Check_Unset_Reference (Left_Opnd (N));
8628 Check_Unset_Reference (Right_Opnd (N));
8629
8630 Set_Etype (N, B_Typ);
8631 Generate_Operator_Reference (N, B_Typ);
8632 Eval_Logical_Op (N);
8633
8634 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8635 -- only when both operands have same static lower and higher bounds. Of
8636 -- course the types have to match, so only check if operands are
8637 -- compatible and the node itself has no errors.
8638
8639 if Is_Array_Type (B_Typ)
8640 and then Nkind (N) in N_Binary_Op
8641 then
8642 declare
8643 Left_Typ : constant Node_Id := Etype (Left_Opnd (N));
8644 Right_Typ : constant Node_Id := Etype (Right_Opnd (N));
8645
8646 begin
8647 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8648 -- operation if not needed.
8649
8650 if Restriction_Check_Required (SPARK_05)
8651 and then Base_Type (Left_Typ) = Base_Type (Right_Typ)
8652 and then Left_Typ /= Any_Composite -- or Left_Opnd in error
8653 and then Right_Typ /= Any_Composite -- or Right_Opnd in error
8654 and then not Matching_Static_Array_Bounds (Left_Typ, Right_Typ)
8655 then
8656 Check_SPARK_05_Restriction
8657 ("array types should have matching static bounds", N);
8658 end if;
8659 end;
8660 end if;
8661 end Resolve_Logical_Op;
8662
8663 ---------------------------
8664 -- Resolve_Membership_Op --
8665 ---------------------------
8666
8667 -- The context can only be a boolean type, and does not determine the
8668 -- arguments. Arguments should be unambiguous, but the preference rule for
8669 -- universal types applies.
8670
8671 procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id) is
8672 pragma Warnings (Off, Typ);
8673
8674 L : constant Node_Id := Left_Opnd (N);
8675 R : constant Node_Id := Right_Opnd (N);
8676 T : Entity_Id;
8677
8678 procedure Resolve_Set_Membership;
8679 -- Analysis has determined a unique type for the left operand. Use it to
8680 -- resolve the disjuncts.
8681
8682 ----------------------------
8683 -- Resolve_Set_Membership --
8684 ----------------------------
8685
8686 procedure Resolve_Set_Membership is
8687 Alt : Node_Id;
8688 Ltyp : Entity_Id;
8689
8690 begin
8691 -- If the left operand is overloaded, find type compatible with not
8692 -- overloaded alternative of the right operand.
8693
8694 if Is_Overloaded (L) then
8695 Ltyp := Empty;
8696 Alt := First (Alternatives (N));
8697 while Present (Alt) loop
8698 if not Is_Overloaded (Alt) then
8699 Ltyp := Intersect_Types (L, Alt);
8700 exit;
8701 else
8702 Next (Alt);
8703 end if;
8704 end loop;
8705
8706 -- Unclear how to resolve expression if all alternatives are also
8707 -- overloaded.
8708
8709 if No (Ltyp) then
8710 Error_Msg_N ("ambiguous expression", N);
8711 end if;
8712
8713 else
8714 Ltyp := Etype (L);
8715 end if;
8716
8717 Resolve (L, Ltyp);
8718
8719 Alt := First (Alternatives (N));
8720 while Present (Alt) loop
8721
8722 -- Alternative is an expression, a range
8723 -- or a subtype mark.
8724
8725 if not Is_Entity_Name (Alt)
8726 or else not Is_Type (Entity (Alt))
8727 then
8728 Resolve (Alt, Ltyp);
8729 end if;
8730
8731 Next (Alt);
8732 end loop;
8733
8734 -- Check for duplicates for discrete case
8735
8736 if Is_Discrete_Type (Ltyp) then
8737 declare
8738 type Ent is record
8739 Alt : Node_Id;
8740 Val : Uint;
8741 end record;
8742
8743 Alts : array (0 .. List_Length (Alternatives (N))) of Ent;
8744 Nalts : Nat;
8745
8746 begin
8747 -- Loop checking duplicates. This is quadratic, but giant sets
8748 -- are unlikely in this context so it's a reasonable choice.
8749
8750 Nalts := 0;
8751 Alt := First (Alternatives (N));
8752 while Present (Alt) loop
8753 if Is_OK_Static_Expression (Alt)
8754 and then (Nkind_In (Alt, N_Integer_Literal,
8755 N_Character_Literal)
8756 or else Nkind (Alt) in N_Has_Entity)
8757 then
8758 Nalts := Nalts + 1;
8759 Alts (Nalts) := (Alt, Expr_Value (Alt));
8760
8761 for J in 1 .. Nalts - 1 loop
8762 if Alts (J).Val = Alts (Nalts).Val then
8763 Error_Msg_Sloc := Sloc (Alts (J).Alt);
8764 Error_Msg_N ("duplicate of value given#??", Alt);
8765 end if;
8766 end loop;
8767 end if;
8768
8769 Alt := Next (Alt);
8770 end loop;
8771 end;
8772 end if;
8773 end Resolve_Set_Membership;
8774
8775 -- Start of processing for Resolve_Membership_Op
8776
8777 begin
8778 if L = Error or else R = Error then
8779 return;
8780 end if;
8781
8782 if Present (Alternatives (N)) then
8783 Resolve_Set_Membership;
8784 goto SM_Exit;
8785
8786 elsif not Is_Overloaded (R)
8787 and then
8788 (Etype (R) = Universal_Integer
8789 or else
8790 Etype (R) = Universal_Real)
8791 and then Is_Overloaded (L)
8792 then
8793 T := Etype (R);
8794
8795 -- Ada 2005 (AI-251): Support the following case:
8796
8797 -- type I is interface;
8798 -- type T is tagged ...
8799
8800 -- function Test (O : I'Class) is
8801 -- begin
8802 -- return O in T'Class.
8803 -- end Test;
8804
8805 -- In this case we have nothing else to do. The membership test will be
8806 -- done at run time.
8807
8808 elsif Ada_Version >= Ada_2005
8809 and then Is_Class_Wide_Type (Etype (L))
8810 and then Is_Interface (Etype (L))
8811 and then Is_Class_Wide_Type (Etype (R))
8812 and then not Is_Interface (Etype (R))
8813 then
8814 return;
8815 else
8816 T := Intersect_Types (L, R);
8817 end if;
8818
8819 -- If mixed-mode operations are present and operands are all literal,
8820 -- the only interpretation involves Duration, which is probably not
8821 -- the intention of the programmer.
8822
8823 if T = Any_Fixed then
8824 T := Unique_Fixed_Point_Type (N);
8825
8826 if T = Any_Type then
8827 return;
8828 end if;
8829 end if;
8830
8831 Resolve (L, T);
8832 Check_Unset_Reference (L);
8833
8834 if Nkind (R) = N_Range
8835 and then not Is_Scalar_Type (T)
8836 then
8837 Error_Msg_N ("scalar type required for range", R);
8838 end if;
8839
8840 if Is_Entity_Name (R) then
8841 Freeze_Expression (R);
8842 else
8843 Resolve (R, T);
8844 Check_Unset_Reference (R);
8845 end if;
8846
8847 -- Here after resolving membership operation
8848
8849 <<SM_Exit>>
8850
8851 Eval_Membership_Op (N);
8852 end Resolve_Membership_Op;
8853
8854 ------------------
8855 -- Resolve_Null --
8856 ------------------
8857
8858 procedure Resolve_Null (N : Node_Id; Typ : Entity_Id) is
8859 Loc : constant Source_Ptr := Sloc (N);
8860
8861 begin
8862 -- Handle restriction against anonymous null access values This
8863 -- restriction can be turned off using -gnatdj.
8864
8865 -- Ada 2005 (AI-231): Remove restriction
8866
8867 if Ada_Version < Ada_2005
8868 and then not Debug_Flag_J
8869 and then Ekind (Typ) = E_Anonymous_Access_Type
8870 and then Comes_From_Source (N)
8871 then
8872 -- In the common case of a call which uses an explicitly null value
8873 -- for an access parameter, give specialized error message.
8874
8875 if Nkind (Parent (N)) in N_Subprogram_Call then
8876 Error_Msg_N
8877 ("null is not allowed as argument for an access parameter", N);
8878
8879 -- Standard message for all other cases (are there any?)
8880
8881 else
8882 Error_Msg_N
8883 ("null cannot be of an anonymous access type", N);
8884 end if;
8885 end if;
8886
8887 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8888 -- assignment to a null-excluding object
8889
8890 if Ada_Version >= Ada_2005
8891 and then Can_Never_Be_Null (Typ)
8892 and then Nkind (Parent (N)) = N_Assignment_Statement
8893 then
8894 if not Inside_Init_Proc then
8895 Insert_Action
8896 (Compile_Time_Constraint_Error (N,
8897 "(Ada 2005) null not allowed in null-excluding objects??"),
8898 Make_Raise_Constraint_Error (Loc,
8899 Reason => CE_Access_Check_Failed));
8900 else
8901 Insert_Action (N,
8902 Make_Raise_Constraint_Error (Loc,
8903 Reason => CE_Access_Check_Failed));
8904 end if;
8905 end if;
8906
8907 -- In a distributed context, null for a remote access to subprogram may
8908 -- need to be replaced with a special record aggregate. In this case,
8909 -- return after having done the transformation.
8910
8911 if (Ekind (Typ) = E_Record_Type
8912 or else Is_Remote_Access_To_Subprogram_Type (Typ))
8913 and then Remote_AST_Null_Value (N, Typ)
8914 then
8915 return;
8916 end if;
8917
8918 -- The null literal takes its type from the context
8919
8920 Set_Etype (N, Typ);
8921 end Resolve_Null;
8922
8923 -----------------------
8924 -- Resolve_Op_Concat --
8925 -----------------------
8926
8927 procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id) is
8928
8929 -- We wish to avoid deep recursion, because concatenations are often
8930 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
8931 -- operands nonrecursively until we find something that is not a simple
8932 -- concatenation (A in this case). We resolve that, and then walk back
8933 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
8934 -- to do the rest of the work at each level. The Parent pointers allow
8935 -- us to avoid recursion, and thus avoid running out of memory. See also
8936 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
8937
8938 NN : Node_Id := N;
8939 Op1 : Node_Id;
8940
8941 begin
8942 -- The following code is equivalent to:
8943
8944 -- Resolve_Op_Concat_First (NN, Typ);
8945 -- Resolve_Op_Concat_Arg (N, ...);
8946 -- Resolve_Op_Concat_Rest (N, Typ);
8947
8948 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
8949 -- operand is a concatenation.
8950
8951 -- Walk down left operands
8952
8953 loop
8954 Resolve_Op_Concat_First (NN, Typ);
8955 Op1 := Left_Opnd (NN);
8956 exit when not (Nkind (Op1) = N_Op_Concat
8957 and then not Is_Array_Type (Component_Type (Typ))
8958 and then Entity (Op1) = Entity (NN));
8959 NN := Op1;
8960 end loop;
8961
8962 -- Now (given the above example) NN is A&B and Op1 is A
8963
8964 -- First resolve Op1 ...
8965
8966 Resolve_Op_Concat_Arg (NN, Op1, Typ, Is_Component_Left_Opnd (NN));
8967
8968 -- ... then walk NN back up until we reach N (where we started), calling
8969 -- Resolve_Op_Concat_Rest along the way.
8970
8971 loop
8972 Resolve_Op_Concat_Rest (NN, Typ);
8973 exit when NN = N;
8974 NN := Parent (NN);
8975 end loop;
8976
8977 if Base_Type (Etype (N)) /= Standard_String then
8978 Check_SPARK_05_Restriction
8979 ("result of concatenation should have type String", N);
8980 end if;
8981 end Resolve_Op_Concat;
8982
8983 ---------------------------
8984 -- Resolve_Op_Concat_Arg --
8985 ---------------------------
8986
8987 procedure Resolve_Op_Concat_Arg
8988 (N : Node_Id;
8989 Arg : Node_Id;
8990 Typ : Entity_Id;
8991 Is_Comp : Boolean)
8992 is
8993 Btyp : constant Entity_Id := Base_Type (Typ);
8994 Ctyp : constant Entity_Id := Component_Type (Typ);
8995
8996 begin
8997 if In_Instance then
8998 if Is_Comp
8999 or else (not Is_Overloaded (Arg)
9000 and then Etype (Arg) /= Any_Composite
9001 and then Covers (Ctyp, Etype (Arg)))
9002 then
9003 Resolve (Arg, Ctyp);
9004 else
9005 Resolve (Arg, Btyp);
9006 end if;
9007
9008 -- If both Array & Array and Array & Component are visible, there is a
9009 -- potential ambiguity that must be reported.
9010
9011 elsif Has_Compatible_Type (Arg, Ctyp) then
9012 if Nkind (Arg) = N_Aggregate
9013 and then Is_Composite_Type (Ctyp)
9014 then
9015 if Is_Private_Type (Ctyp) then
9016 Resolve (Arg, Btyp);
9017
9018 -- If the operation is user-defined and not overloaded use its
9019 -- profile. The operation may be a renaming, in which case it has
9020 -- been rewritten, and we want the original profile.
9021
9022 elsif not Is_Overloaded (N)
9023 and then Comes_From_Source (Entity (Original_Node (N)))
9024 and then Ekind (Entity (Original_Node (N))) = E_Function
9025 then
9026 Resolve (Arg,
9027 Etype
9028 (Next_Formal (First_Formal (Entity (Original_Node (N))))));
9029 return;
9030
9031 -- Otherwise an aggregate may match both the array type and the
9032 -- component type.
9033
9034 else
9035 Error_Msg_N ("ambiguous aggregate must be qualified", Arg);
9036 Set_Etype (Arg, Any_Type);
9037 end if;
9038
9039 else
9040 if Is_Overloaded (Arg)
9041 and then Has_Compatible_Type (Arg, Typ)
9042 and then Etype (Arg) /= Any_Type
9043 then
9044 declare
9045 I : Interp_Index;
9046 It : Interp;
9047 Func : Entity_Id;
9048
9049 begin
9050 Get_First_Interp (Arg, I, It);
9051 Func := It.Nam;
9052 Get_Next_Interp (I, It);
9053
9054 -- Special-case the error message when the overloading is
9055 -- caused by a function that yields an array and can be
9056 -- called without parameters.
9057
9058 if It.Nam = Func then
9059 Error_Msg_Sloc := Sloc (Func);
9060 Error_Msg_N ("ambiguous call to function#", Arg);
9061 Error_Msg_NE
9062 ("\\interpretation as call yields&", Arg, Typ);
9063 Error_Msg_NE
9064 ("\\interpretation as indexing of call yields&",
9065 Arg, Component_Type (Typ));
9066
9067 else
9068 Error_Msg_N ("ambiguous operand for concatenation!", Arg);
9069
9070 Get_First_Interp (Arg, I, It);
9071 while Present (It.Nam) loop
9072 Error_Msg_Sloc := Sloc (It.Nam);
9073
9074 if Base_Type (It.Typ) = Btyp
9075 or else
9076 Base_Type (It.Typ) = Base_Type (Ctyp)
9077 then
9078 Error_Msg_N -- CODEFIX
9079 ("\\possible interpretation#", Arg);
9080 end if;
9081
9082 Get_Next_Interp (I, It);
9083 end loop;
9084 end if;
9085 end;
9086 end if;
9087
9088 Resolve (Arg, Component_Type (Typ));
9089
9090 if Nkind (Arg) = N_String_Literal then
9091 Set_Etype (Arg, Component_Type (Typ));
9092 end if;
9093
9094 if Arg = Left_Opnd (N) then
9095 Set_Is_Component_Left_Opnd (N);
9096 else
9097 Set_Is_Component_Right_Opnd (N);
9098 end if;
9099 end if;
9100
9101 else
9102 Resolve (Arg, Btyp);
9103 end if;
9104
9105 -- Concatenation is restricted in SPARK: each operand must be either a
9106 -- string literal, the name of a string constant, a static character or
9107 -- string expression, or another concatenation. Arg cannot be a
9108 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9109 -- separately on each final operand, past concatenation operations.
9110
9111 if Is_Character_Type (Etype (Arg)) then
9112 if not Is_OK_Static_Expression (Arg) then
9113 Check_SPARK_05_Restriction
9114 ("character operand for concatenation should be static", Arg);
9115 end if;
9116
9117 elsif Is_String_Type (Etype (Arg)) then
9118 if not (Nkind_In (Arg, N_Identifier, N_Expanded_Name)
9119 and then Is_Constant_Object (Entity (Arg)))
9120 and then not Is_OK_Static_Expression (Arg)
9121 then
9122 Check_SPARK_05_Restriction
9123 ("string operand for concatenation should be static", Arg);
9124 end if;
9125
9126 -- Do not issue error on an operand that is neither a character nor a
9127 -- string, as the error is issued in Resolve_Op_Concat.
9128
9129 else
9130 null;
9131 end if;
9132
9133 Check_Unset_Reference (Arg);
9134 end Resolve_Op_Concat_Arg;
9135
9136 -----------------------------
9137 -- Resolve_Op_Concat_First --
9138 -----------------------------
9139
9140 procedure Resolve_Op_Concat_First (N : Node_Id; Typ : Entity_Id) is
9141 Btyp : constant Entity_Id := Base_Type (Typ);
9142 Op1 : constant Node_Id := Left_Opnd (N);
9143 Op2 : constant Node_Id := Right_Opnd (N);
9144
9145 begin
9146 -- The parser folds an enormous sequence of concatenations of string
9147 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9148 -- in the right operand. If the expression resolves to a predefined "&"
9149 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9150 -- we give an error. See P_Simple_Expression in Par.Ch4.
9151
9152 if Nkind (Op2) = N_String_Literal
9153 and then Is_Folded_In_Parser (Op2)
9154 and then Ekind (Entity (N)) = E_Function
9155 then
9156 pragma Assert (Nkind (Op1) = N_String_Literal -- should be ""
9157 and then String_Length (Strval (Op1)) = 0);
9158 Error_Msg_N ("too many user-defined concatenations", N);
9159 return;
9160 end if;
9161
9162 Set_Etype (N, Btyp);
9163
9164 if Is_Limited_Composite (Btyp) then
9165 Error_Msg_N ("concatenation not available for limited array", N);
9166 Explain_Limited_Type (Btyp, N);
9167 end if;
9168 end Resolve_Op_Concat_First;
9169
9170 ----------------------------
9171 -- Resolve_Op_Concat_Rest --
9172 ----------------------------
9173
9174 procedure Resolve_Op_Concat_Rest (N : Node_Id; Typ : Entity_Id) is
9175 Op1 : constant Node_Id := Left_Opnd (N);
9176 Op2 : constant Node_Id := Right_Opnd (N);
9177
9178 begin
9179 Resolve_Op_Concat_Arg (N, Op2, Typ, Is_Component_Right_Opnd (N));
9180
9181 Generate_Operator_Reference (N, Typ);
9182
9183 if Is_String_Type (Typ) then
9184 Eval_Concatenation (N);
9185 end if;
9186
9187 -- If this is not a static concatenation, but the result is a string
9188 -- type (and not an array of strings) ensure that static string operands
9189 -- have their subtypes properly constructed.
9190
9191 if Nkind (N) /= N_String_Literal
9192 and then Is_Character_Type (Component_Type (Typ))
9193 then
9194 Set_String_Literal_Subtype (Op1, Typ);
9195 Set_String_Literal_Subtype (Op2, Typ);
9196 end if;
9197 end Resolve_Op_Concat_Rest;
9198
9199 ----------------------
9200 -- Resolve_Op_Expon --
9201 ----------------------
9202
9203 procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id) is
9204 B_Typ : constant Entity_Id := Base_Type (Typ);
9205
9206 begin
9207 -- Catch attempts to do fixed-point exponentiation with universal
9208 -- operands, which is a case where the illegality is not caught during
9209 -- normal operator analysis. This is not done in preanalysis mode
9210 -- since the tree is not fully decorated during preanalysis.
9211
9212 if Full_Analysis then
9213 if Is_Fixed_Point_Type (Typ) and then Comes_From_Source (N) then
9214 Error_Msg_N ("exponentiation not available for fixed point", N);
9215 return;
9216
9217 elsif Nkind (Parent (N)) in N_Op
9218 and then Is_Fixed_Point_Type (Etype (Parent (N)))
9219 and then Etype (N) = Universal_Real
9220 and then Comes_From_Source (N)
9221 then
9222 Error_Msg_N ("exponentiation not available for fixed point", N);
9223 return;
9224 end if;
9225 end if;
9226
9227 if Comes_From_Source (N)
9228 and then Ekind (Entity (N)) = E_Function
9229 and then Is_Imported (Entity (N))
9230 and then Is_Intrinsic_Subprogram (Entity (N))
9231 then
9232 Resolve_Intrinsic_Operator (N, Typ);
9233 return;
9234 end if;
9235
9236 if Etype (Left_Opnd (N)) = Universal_Integer
9237 or else Etype (Left_Opnd (N)) = Universal_Real
9238 then
9239 Check_For_Visible_Operator (N, B_Typ);
9240 end if;
9241
9242 -- We do the resolution using the base type, because intermediate values
9243 -- in expressions are always of the base type, not a subtype of it.
9244
9245 Resolve (Left_Opnd (N), B_Typ);
9246 Resolve (Right_Opnd (N), Standard_Integer);
9247
9248 -- For integer types, right argument must be in Natural range
9249
9250 if Is_Integer_Type (Typ) then
9251 Apply_Scalar_Range_Check (Right_Opnd (N), Standard_Natural);
9252 end if;
9253
9254 Check_Unset_Reference (Left_Opnd (N));
9255 Check_Unset_Reference (Right_Opnd (N));
9256
9257 Set_Etype (N, B_Typ);
9258 Generate_Operator_Reference (N, B_Typ);
9259
9260 Analyze_Dimension (N);
9261
9262 if Ada_Version >= Ada_2012 and then Has_Dimension_System (B_Typ) then
9263 -- Evaluate the exponentiation operator for dimensioned type
9264
9265 Eval_Op_Expon_For_Dimensioned_Type (N, B_Typ);
9266 else
9267 Eval_Op_Expon (N);
9268 end if;
9269
9270 -- Set overflow checking bit. Much cleverer code needed here eventually
9271 -- and perhaps the Resolve routines should be separated for the various
9272 -- arithmetic operations, since they will need different processing. ???
9273
9274 if Nkind (N) in N_Op then
9275 if not Overflow_Checks_Suppressed (Etype (N)) then
9276 Enable_Overflow_Check (N);
9277 end if;
9278 end if;
9279 end Resolve_Op_Expon;
9280
9281 --------------------
9282 -- Resolve_Op_Not --
9283 --------------------
9284
9285 procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id) is
9286 B_Typ : Entity_Id;
9287
9288 function Parent_Is_Boolean return Boolean;
9289 -- This function determines if the parent node is a boolean operator or
9290 -- operation (comparison op, membership test, or short circuit form) and
9291 -- the not in question is the left operand of this operation. Note that
9292 -- if the not is in parens, then false is returned.
9293
9294 -----------------------
9295 -- Parent_Is_Boolean --
9296 -----------------------
9297
9298 function Parent_Is_Boolean return Boolean is
9299 begin
9300 if Paren_Count (N) /= 0 then
9301 return False;
9302
9303 else
9304 case Nkind (Parent (N)) is
9305 when N_Op_And |
9306 N_Op_Eq |
9307 N_Op_Ge |
9308 N_Op_Gt |
9309 N_Op_Le |
9310 N_Op_Lt |
9311 N_Op_Ne |
9312 N_Op_Or |
9313 N_Op_Xor |
9314 N_In |
9315 N_Not_In |
9316 N_And_Then |
9317 N_Or_Else =>
9318
9319 return Left_Opnd (Parent (N)) = N;
9320
9321 when others =>
9322 return False;
9323 end case;
9324 end if;
9325 end Parent_Is_Boolean;
9326
9327 -- Start of processing for Resolve_Op_Not
9328
9329 begin
9330 -- Predefined operations on scalar types yield the base type. On the
9331 -- other hand, logical operations on arrays yield the type of the
9332 -- arguments (and the context).
9333
9334 if Is_Array_Type (Typ) then
9335 B_Typ := Typ;
9336 else
9337 B_Typ := Base_Type (Typ);
9338 end if;
9339
9340 -- Straightforward case of incorrect arguments
9341
9342 if not Valid_Boolean_Arg (Typ) then
9343 Error_Msg_N ("invalid operand type for operator&", N);
9344 Set_Etype (N, Any_Type);
9345 return;
9346
9347 -- Special case of probable missing parens
9348
9349 elsif Typ = Universal_Integer or else Typ = Any_Modular then
9350 if Parent_Is_Boolean then
9351 Error_Msg_N
9352 ("operand of not must be enclosed in parentheses",
9353 Right_Opnd (N));
9354 else
9355 Error_Msg_N
9356 ("no modular type available in this context", N);
9357 end if;
9358
9359 Set_Etype (N, Any_Type);
9360 return;
9361
9362 -- OK resolution of NOT
9363
9364 else
9365 -- Warn if non-boolean types involved. This is a case like not a < b
9366 -- where a and b are modular, where we will get (not a) < b and most
9367 -- likely not (a < b) was intended.
9368
9369 if Warn_On_Questionable_Missing_Parens
9370 and then not Is_Boolean_Type (Typ)
9371 and then Parent_Is_Boolean
9372 then
9373 Error_Msg_N ("?q?not expression should be parenthesized here!", N);
9374 end if;
9375
9376 -- Warn on double negation if checking redundant constructs
9377
9378 if Warn_On_Redundant_Constructs
9379 and then Comes_From_Source (N)
9380 and then Comes_From_Source (Right_Opnd (N))
9381 and then Root_Type (Typ) = Standard_Boolean
9382 and then Nkind (Right_Opnd (N)) = N_Op_Not
9383 then
9384 Error_Msg_N ("redundant double negation?r?", N);
9385 end if;
9386
9387 -- Complete resolution and evaluation of NOT
9388
9389 Resolve (Right_Opnd (N), B_Typ);
9390 Check_Unset_Reference (Right_Opnd (N));
9391 Set_Etype (N, B_Typ);
9392 Generate_Operator_Reference (N, B_Typ);
9393 Eval_Op_Not (N);
9394 end if;
9395 end Resolve_Op_Not;
9396
9397 -----------------------------
9398 -- Resolve_Operator_Symbol --
9399 -----------------------------
9400
9401 -- Nothing to be done, all resolved already
9402
9403 procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id) is
9404 pragma Warnings (Off, N);
9405 pragma Warnings (Off, Typ);
9406
9407 begin
9408 null;
9409 end Resolve_Operator_Symbol;
9410
9411 ----------------------------------
9412 -- Resolve_Qualified_Expression --
9413 ----------------------------------
9414
9415 procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id) is
9416 pragma Warnings (Off, Typ);
9417
9418 Target_Typ : constant Entity_Id := Entity (Subtype_Mark (N));
9419 Expr : constant Node_Id := Expression (N);
9420
9421 begin
9422 Resolve (Expr, Target_Typ);
9423
9424 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9425 -- operation if not needed.
9426
9427 if Restriction_Check_Required (SPARK_05)
9428 and then Is_Array_Type (Target_Typ)
9429 and then Is_Array_Type (Etype (Expr))
9430 and then Etype (Expr) /= Any_Composite -- or else Expr in error
9431 and then not Matching_Static_Array_Bounds (Target_Typ, Etype (Expr))
9432 then
9433 Check_SPARK_05_Restriction
9434 ("array types should have matching static bounds", N);
9435 end if;
9436
9437 -- A qualified expression requires an exact match of the type, class-
9438 -- wide matching is not allowed. However, if the qualifying type is
9439 -- specific and the expression has a class-wide type, it may still be
9440 -- okay, since it can be the result of the expansion of a call to a
9441 -- dispatching function, so we also have to check class-wideness of the
9442 -- type of the expression's original node.
9443
9444 if (Is_Class_Wide_Type (Target_Typ)
9445 or else
9446 (Is_Class_Wide_Type (Etype (Expr))
9447 and then Is_Class_Wide_Type (Etype (Original_Node (Expr)))))
9448 and then Base_Type (Etype (Expr)) /= Base_Type (Target_Typ)
9449 then
9450 Wrong_Type (Expr, Target_Typ);
9451 end if;
9452
9453 -- If the target type is unconstrained, then we reset the type of the
9454 -- result from the type of the expression. For other cases, the actual
9455 -- subtype of the expression is the target type.
9456
9457 if Is_Composite_Type (Target_Typ)
9458 and then not Is_Constrained (Target_Typ)
9459 then
9460 Set_Etype (N, Etype (Expr));
9461 end if;
9462
9463 Analyze_Dimension (N);
9464 Eval_Qualified_Expression (N);
9465
9466 -- If we still have a qualified expression after the static evaluation,
9467 -- then apply a scalar range check if needed. The reason that we do this
9468 -- after the Eval call is that otherwise, the application of the range
9469 -- check may convert an illegal static expression and result in warning
9470 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9471
9472 if Nkind (N) = N_Qualified_Expression and then Is_Scalar_Type (Typ) then
9473 Apply_Scalar_Range_Check (Expr, Typ);
9474 end if;
9475
9476 -- Finally, check whether a predicate applies to the target type. This
9477 -- comes from AI12-0100. As for type conversions, check the enclosing
9478 -- context to prevent an infinite expansion.
9479
9480 if Has_Predicates (Target_Typ) then
9481 if Nkind (Parent (N)) = N_Function_Call
9482 and then Present (Name (Parent (N)))
9483 and then (Is_Predicate_Function (Entity (Name (Parent (N))))
9484 or else
9485 Is_Predicate_Function_M (Entity (Name (Parent (N)))))
9486 then
9487 null;
9488
9489 elsif Nkind (N) = N_Qualified_Expression then
9490 Apply_Predicate_Check (N, Target_Typ);
9491 end if;
9492 end if;
9493 end Resolve_Qualified_Expression;
9494
9495 ------------------------------
9496 -- Resolve_Raise_Expression --
9497 ------------------------------
9498
9499 procedure Resolve_Raise_Expression (N : Node_Id; Typ : Entity_Id) is
9500 begin
9501 if Typ = Raise_Type then
9502 Error_Msg_N ("cannot find unique type for raise expression", N);
9503 Set_Etype (N, Any_Type);
9504 else
9505 Set_Etype (N, Typ);
9506 end if;
9507 end Resolve_Raise_Expression;
9508
9509 -------------------
9510 -- Resolve_Range --
9511 -------------------
9512
9513 procedure Resolve_Range (N : Node_Id; Typ : Entity_Id) is
9514 L : constant Node_Id := Low_Bound (N);
9515 H : constant Node_Id := High_Bound (N);
9516
9517 function First_Last_Ref return Boolean;
9518 -- Returns True if N is of the form X'First .. X'Last where X is the
9519 -- same entity for both attributes.
9520
9521 --------------------
9522 -- First_Last_Ref --
9523 --------------------
9524
9525 function First_Last_Ref return Boolean is
9526 Lorig : constant Node_Id := Original_Node (L);
9527 Horig : constant Node_Id := Original_Node (H);
9528
9529 begin
9530 if Nkind (Lorig) = N_Attribute_Reference
9531 and then Nkind (Horig) = N_Attribute_Reference
9532 and then Attribute_Name (Lorig) = Name_First
9533 and then Attribute_Name (Horig) = Name_Last
9534 then
9535 declare
9536 PL : constant Node_Id := Prefix (Lorig);
9537 PH : constant Node_Id := Prefix (Horig);
9538 begin
9539 if Is_Entity_Name (PL)
9540 and then Is_Entity_Name (PH)
9541 and then Entity (PL) = Entity (PH)
9542 then
9543 return True;
9544 end if;
9545 end;
9546 end if;
9547
9548 return False;
9549 end First_Last_Ref;
9550
9551 -- Start of processing for Resolve_Range
9552
9553 begin
9554 Set_Etype (N, Typ);
9555 Resolve (L, Typ);
9556 Resolve (H, Typ);
9557
9558 -- Check for inappropriate range on unordered enumeration type
9559
9560 if Bad_Unordered_Enumeration_Reference (N, Typ)
9561
9562 -- Exclude X'First .. X'Last if X is the same entity for both
9563
9564 and then not First_Last_Ref
9565 then
9566 Error_Msg_Sloc := Sloc (Typ);
9567 Error_Msg_NE
9568 ("subrange of unordered enumeration type& declared#?U?", N, Typ);
9569 end if;
9570
9571 Check_Unset_Reference (L);
9572 Check_Unset_Reference (H);
9573
9574 -- We have to check the bounds for being within the base range as
9575 -- required for a non-static context. Normally this is automatic and
9576 -- done as part of evaluating expressions, but the N_Range node is an
9577 -- exception, since in GNAT we consider this node to be a subexpression,
9578 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9579 -- this, but that would put the test on the main evaluation path for
9580 -- expressions.
9581
9582 Check_Non_Static_Context (L);
9583 Check_Non_Static_Context (H);
9584
9585 -- Check for an ambiguous range over character literals. This will
9586 -- happen with a membership test involving only literals.
9587
9588 if Typ = Any_Character then
9589 Ambiguous_Character (L);
9590 Set_Etype (N, Any_Type);
9591 return;
9592 end if;
9593
9594 -- If bounds are static, constant-fold them, so size computations are
9595 -- identical between front-end and back-end. Do not perform this
9596 -- transformation while analyzing generic units, as type information
9597 -- would be lost when reanalyzing the constant node in the instance.
9598
9599 if Is_Discrete_Type (Typ) and then Expander_Active then
9600 if Is_OK_Static_Expression (L) then
9601 Fold_Uint (L, Expr_Value (L), Is_OK_Static_Expression (L));
9602 end if;
9603
9604 if Is_OK_Static_Expression (H) then
9605 Fold_Uint (H, Expr_Value (H), Is_OK_Static_Expression (H));
9606 end if;
9607 end if;
9608 end Resolve_Range;
9609
9610 --------------------------
9611 -- Resolve_Real_Literal --
9612 --------------------------
9613
9614 procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id) is
9615 Actual_Typ : constant Entity_Id := Etype (N);
9616
9617 begin
9618 -- Special processing for fixed-point literals to make sure that the
9619 -- value is an exact multiple of small where this is required. We skip
9620 -- this for the universal real case, and also for generic types.
9621
9622 if Is_Fixed_Point_Type (Typ)
9623 and then Typ /= Universal_Fixed
9624 and then Typ /= Any_Fixed
9625 and then not Is_Generic_Type (Typ)
9626 then
9627 declare
9628 Val : constant Ureal := Realval (N);
9629 Cintr : constant Ureal := Val / Small_Value (Typ);
9630 Cint : constant Uint := UR_Trunc (Cintr);
9631 Den : constant Uint := Norm_Den (Cintr);
9632 Stat : Boolean;
9633
9634 begin
9635 -- Case of literal is not an exact multiple of the Small
9636
9637 if Den /= 1 then
9638
9639 -- For a source program literal for a decimal fixed-point type,
9640 -- this is statically illegal (RM 4.9(36)).
9641
9642 if Is_Decimal_Fixed_Point_Type (Typ)
9643 and then Actual_Typ = Universal_Real
9644 and then Comes_From_Source (N)
9645 then
9646 Error_Msg_N ("value has extraneous low order digits", N);
9647 end if;
9648
9649 -- Generate a warning if literal from source
9650
9651 if Is_OK_Static_Expression (N)
9652 and then Warn_On_Bad_Fixed_Value
9653 then
9654 Error_Msg_N
9655 ("?b?static fixed-point value is not a multiple of Small!",
9656 N);
9657 end if;
9658
9659 -- Replace literal by a value that is the exact representation
9660 -- of a value of the type, i.e. a multiple of the small value,
9661 -- by truncation, since Machine_Rounds is false for all GNAT
9662 -- fixed-point types (RM 4.9(38)).
9663
9664 Stat := Is_OK_Static_Expression (N);
9665 Rewrite (N,
9666 Make_Real_Literal (Sloc (N),
9667 Realval => Small_Value (Typ) * Cint));
9668
9669 Set_Is_Static_Expression (N, Stat);
9670 end if;
9671
9672 -- In all cases, set the corresponding integer field
9673
9674 Set_Corresponding_Integer_Value (N, Cint);
9675 end;
9676 end if;
9677
9678 -- Now replace the actual type by the expected type as usual
9679
9680 Set_Etype (N, Typ);
9681 Eval_Real_Literal (N);
9682 end Resolve_Real_Literal;
9683
9684 -----------------------
9685 -- Resolve_Reference --
9686 -----------------------
9687
9688 procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id) is
9689 P : constant Node_Id := Prefix (N);
9690
9691 begin
9692 -- Replace general access with specific type
9693
9694 if Ekind (Etype (N)) = E_Allocator_Type then
9695 Set_Etype (N, Base_Type (Typ));
9696 end if;
9697
9698 Resolve (P, Designated_Type (Etype (N)));
9699
9700 -- If we are taking the reference of a volatile entity, then treat it as
9701 -- a potential modification of this entity. This is too conservative,
9702 -- but necessary because remove side effects can cause transformations
9703 -- of normal assignments into reference sequences that otherwise fail to
9704 -- notice the modification.
9705
9706 if Is_Entity_Name (P) and then Treat_As_Volatile (Entity (P)) then
9707 Note_Possible_Modification (P, Sure => False);
9708 end if;
9709 end Resolve_Reference;
9710
9711 --------------------------------
9712 -- Resolve_Selected_Component --
9713 --------------------------------
9714
9715 procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id) is
9716 Comp : Entity_Id;
9717 Comp1 : Entity_Id := Empty; -- prevent junk warning
9718 P : constant Node_Id := Prefix (N);
9719 S : constant Node_Id := Selector_Name (N);
9720 T : Entity_Id := Etype (P);
9721 I : Interp_Index;
9722 I1 : Interp_Index := 0; -- prevent junk warning
9723 It : Interp;
9724 It1 : Interp;
9725 Found : Boolean;
9726
9727 function Init_Component return Boolean;
9728 -- Check whether this is the initialization of a component within an
9729 -- init proc (by assignment or call to another init proc). If true,
9730 -- there is no need for a discriminant check.
9731
9732 --------------------
9733 -- Init_Component --
9734 --------------------
9735
9736 function Init_Component return Boolean is
9737 begin
9738 return Inside_Init_Proc
9739 and then Nkind (Prefix (N)) = N_Identifier
9740 and then Chars (Prefix (N)) = Name_uInit
9741 and then Nkind (Parent (Parent (N))) = N_Case_Statement_Alternative;
9742 end Init_Component;
9743
9744 -- Start of processing for Resolve_Selected_Component
9745
9746 begin
9747 if Is_Overloaded (P) then
9748
9749 -- Use the context type to select the prefix that has a selector
9750 -- of the correct name and type.
9751
9752 Found := False;
9753 Get_First_Interp (P, I, It);
9754
9755 Search : while Present (It.Typ) loop
9756 if Is_Access_Type (It.Typ) then
9757 T := Designated_Type (It.Typ);
9758 else
9759 T := It.Typ;
9760 end if;
9761
9762 -- Locate selected component. For a private prefix the selector
9763 -- can denote a discriminant.
9764
9765 if Is_Record_Type (T) or else Is_Private_Type (T) then
9766
9767 -- The visible components of a class-wide type are those of
9768 -- the root type.
9769
9770 if Is_Class_Wide_Type (T) then
9771 T := Etype (T);
9772 end if;
9773
9774 Comp := First_Entity (T);
9775 while Present (Comp) loop
9776 if Chars (Comp) = Chars (S)
9777 and then Covers (Typ, Etype (Comp))
9778 then
9779 if not Found then
9780 Found := True;
9781 I1 := I;
9782 It1 := It;
9783 Comp1 := Comp;
9784
9785 else
9786 It := Disambiguate (P, I1, I, Any_Type);
9787
9788 if It = No_Interp then
9789 Error_Msg_N
9790 ("ambiguous prefix for selected component", N);
9791 Set_Etype (N, Typ);
9792 return;
9793
9794 else
9795 It1 := It;
9796
9797 -- There may be an implicit dereference. Retrieve
9798 -- designated record type.
9799
9800 if Is_Access_Type (It1.Typ) then
9801 T := Designated_Type (It1.Typ);
9802 else
9803 T := It1.Typ;
9804 end if;
9805
9806 if Scope (Comp1) /= T then
9807
9808 -- Resolution chooses the new interpretation.
9809 -- Find the component with the right name.
9810
9811 Comp1 := First_Entity (T);
9812 while Present (Comp1)
9813 and then Chars (Comp1) /= Chars (S)
9814 loop
9815 Comp1 := Next_Entity (Comp1);
9816 end loop;
9817 end if;
9818
9819 exit Search;
9820 end if;
9821 end if;
9822 end if;
9823
9824 Comp := Next_Entity (Comp);
9825 end loop;
9826 end if;
9827
9828 Get_Next_Interp (I, It);
9829 end loop Search;
9830
9831 -- There must be a legal interpretation at this point
9832
9833 pragma Assert (Found);
9834 Resolve (P, It1.Typ);
9835 Set_Etype (N, Typ);
9836 Set_Entity_With_Checks (S, Comp1);
9837
9838 else
9839 -- Resolve prefix with its type
9840
9841 Resolve (P, T);
9842 end if;
9843
9844 -- Generate cross-reference. We needed to wait until full overloading
9845 -- resolution was complete to do this, since otherwise we can't tell if
9846 -- we are an lvalue or not.
9847
9848 if May_Be_Lvalue (N) then
9849 Generate_Reference (Entity (S), S, 'm');
9850 else
9851 Generate_Reference (Entity (S), S, 'r');
9852 end if;
9853
9854 -- If prefix is an access type, the node will be transformed into an
9855 -- explicit dereference during expansion. The type of the node is the
9856 -- designated type of that of the prefix.
9857
9858 if Is_Access_Type (Etype (P)) then
9859 T := Designated_Type (Etype (P));
9860 Check_Fully_Declared_Prefix (T, P);
9861 else
9862 T := Etype (P);
9863 end if;
9864
9865 -- Set flag for expander if discriminant check required on a component
9866 -- appearing within a variant.
9867
9868 if Has_Discriminants (T)
9869 and then Ekind (Entity (S)) = E_Component
9870 and then Present (Original_Record_Component (Entity (S)))
9871 and then Ekind (Original_Record_Component (Entity (S))) = E_Component
9872 and then
9873 Is_Declared_Within_Variant (Original_Record_Component (Entity (S)))
9874 and then not Discriminant_Checks_Suppressed (T)
9875 and then not Init_Component
9876 then
9877 Set_Do_Discriminant_Check (N);
9878 end if;
9879
9880 if Ekind (Entity (S)) = E_Void then
9881 Error_Msg_N ("premature use of component", S);
9882 end if;
9883
9884 -- If the prefix is a record conversion, this may be a renamed
9885 -- discriminant whose bounds differ from those of the original
9886 -- one, so we must ensure that a range check is performed.
9887
9888 if Nkind (P) = N_Type_Conversion
9889 and then Ekind (Entity (S)) = E_Discriminant
9890 and then Is_Discrete_Type (Typ)
9891 then
9892 Set_Etype (N, Base_Type (Typ));
9893 end if;
9894
9895 -- Note: No Eval processing is required, because the prefix is of a
9896 -- record type, or protected type, and neither can possibly be static.
9897
9898 -- If the record type is atomic, and the component is non-atomic, then
9899 -- this is worth a warning, since we have a situation where the access
9900 -- to the component may cause extra read/writes of the atomic array
9901 -- object, or partial word accesses, both of which may be unexpected.
9902
9903 if Nkind (N) = N_Selected_Component
9904 and then Is_Atomic_Ref_With_Address (N)
9905 and then not Is_Atomic (Entity (S))
9906 and then not Is_Atomic (Etype (Entity (S)))
9907 then
9908 Error_Msg_N
9909 ("??access to non-atomic component of atomic record",
9910 Prefix (N));
9911 Error_Msg_N
9912 ("\??may cause unexpected accesses to atomic object",
9913 Prefix (N));
9914 end if;
9915
9916 Analyze_Dimension (N);
9917 end Resolve_Selected_Component;
9918
9919 -------------------
9920 -- Resolve_Shift --
9921 -------------------
9922
9923 procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id) is
9924 B_Typ : constant Entity_Id := Base_Type (Typ);
9925 L : constant Node_Id := Left_Opnd (N);
9926 R : constant Node_Id := Right_Opnd (N);
9927
9928 begin
9929 -- We do the resolution using the base type, because intermediate values
9930 -- in expressions always are of the base type, not a subtype of it.
9931
9932 Resolve (L, B_Typ);
9933 Resolve (R, Standard_Natural);
9934
9935 Check_Unset_Reference (L);
9936 Check_Unset_Reference (R);
9937
9938 Set_Etype (N, B_Typ);
9939 Generate_Operator_Reference (N, B_Typ);
9940 Eval_Shift (N);
9941 end Resolve_Shift;
9942
9943 ---------------------------
9944 -- Resolve_Short_Circuit --
9945 ---------------------------
9946
9947 procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id) is
9948 B_Typ : constant Entity_Id := Base_Type (Typ);
9949 L : constant Node_Id := Left_Opnd (N);
9950 R : constant Node_Id := Right_Opnd (N);
9951
9952 begin
9953 -- Ensure all actions associated with the left operand (e.g.
9954 -- finalization of transient controlled objects) are fully evaluated
9955 -- locally within an expression with actions. This is particularly
9956 -- helpful for coverage analysis. However this should not happen in
9957 -- generics or if Minimize_Expression_With_Actions is set.
9958
9959 if Expander_Active and not Minimize_Expression_With_Actions then
9960 declare
9961 Reloc_L : constant Node_Id := Relocate_Node (L);
9962 begin
9963 Save_Interps (Old_N => L, New_N => Reloc_L);
9964
9965 Rewrite (L,
9966 Make_Expression_With_Actions (Sloc (L),
9967 Actions => New_List,
9968 Expression => Reloc_L));
9969
9970 -- Set Comes_From_Source on L to preserve warnings for unset
9971 -- reference.
9972
9973 Set_Comes_From_Source (L, Comes_From_Source (Reloc_L));
9974 end;
9975 end if;
9976
9977 Resolve (L, B_Typ);
9978 Resolve (R, B_Typ);
9979
9980 -- Check for issuing warning for always False assert/check, this happens
9981 -- when assertions are turned off, in which case the pragma Assert/Check
9982 -- was transformed into:
9983
9984 -- if False and then <condition> then ...
9985
9986 -- and we detect this pattern
9987
9988 if Warn_On_Assertion_Failure
9989 and then Is_Entity_Name (R)
9990 and then Entity (R) = Standard_False
9991 and then Nkind (Parent (N)) = N_If_Statement
9992 and then Nkind (N) = N_And_Then
9993 and then Is_Entity_Name (L)
9994 and then Entity (L) = Standard_False
9995 then
9996 declare
9997 Orig : constant Node_Id := Original_Node (Parent (N));
9998
9999 begin
10000 -- Special handling of Asssert pragma
10001
10002 if Nkind (Orig) = N_Pragma
10003 and then Pragma_Name (Orig) = Name_Assert
10004 then
10005 declare
10006 Expr : constant Node_Id :=
10007 Original_Node
10008 (Expression
10009 (First (Pragma_Argument_Associations (Orig))));
10010
10011 begin
10012 -- Don't warn if original condition is explicit False,
10013 -- since obviously the failure is expected in this case.
10014
10015 if Is_Entity_Name (Expr)
10016 and then Entity (Expr) = Standard_False
10017 then
10018 null;
10019
10020 -- Issue warning. We do not want the deletion of the
10021 -- IF/AND-THEN to take this message with it. We achieve this
10022 -- by making sure that the expanded code points to the Sloc
10023 -- of the expression, not the original pragma.
10024
10025 else
10026 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10027 -- The source location of the expression is not usually
10028 -- the best choice here. For example, it gets located on
10029 -- the last AND keyword in a chain of boolean expressiond
10030 -- AND'ed together. It is best to put the message on the
10031 -- first character of the assertion, which is the effect
10032 -- of the First_Node call here.
10033
10034 Error_Msg_F
10035 ("?A?assertion would fail at run time!",
10036 Expression
10037 (First (Pragma_Argument_Associations (Orig))));
10038 end if;
10039 end;
10040
10041 -- Similar processing for Check pragma
10042
10043 elsif Nkind (Orig) = N_Pragma
10044 and then Pragma_Name (Orig) = Name_Check
10045 then
10046 -- Don't want to warn if original condition is explicit False
10047
10048 declare
10049 Expr : constant Node_Id :=
10050 Original_Node
10051 (Expression
10052 (Next (First (Pragma_Argument_Associations (Orig)))));
10053 begin
10054 if Is_Entity_Name (Expr)
10055 and then Entity (Expr) = Standard_False
10056 then
10057 null;
10058
10059 -- Post warning
10060
10061 else
10062 -- Again use Error_Msg_F rather than Error_Msg_N, see
10063 -- comment above for an explanation of why we do this.
10064
10065 Error_Msg_F
10066 ("?A?check would fail at run time!",
10067 Expression
10068 (Last (Pragma_Argument_Associations (Orig))));
10069 end if;
10070 end;
10071 end if;
10072 end;
10073 end if;
10074
10075 -- Continue with processing of short circuit
10076
10077 Check_Unset_Reference (L);
10078 Check_Unset_Reference (R);
10079
10080 Set_Etype (N, B_Typ);
10081 Eval_Short_Circuit (N);
10082 end Resolve_Short_Circuit;
10083
10084 -------------------
10085 -- Resolve_Slice --
10086 -------------------
10087
10088 procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id) is
10089 Drange : constant Node_Id := Discrete_Range (N);
10090 Name : constant Node_Id := Prefix (N);
10091 Array_Type : Entity_Id := Empty;
10092 Dexpr : Node_Id := Empty;
10093 Index_Type : Entity_Id;
10094
10095 begin
10096 if Is_Overloaded (Name) then
10097
10098 -- Use the context type to select the prefix that yields the correct
10099 -- array type.
10100
10101 declare
10102 I : Interp_Index;
10103 I1 : Interp_Index := 0;
10104 It : Interp;
10105 P : constant Node_Id := Prefix (N);
10106 Found : Boolean := False;
10107
10108 begin
10109 Get_First_Interp (P, I, It);
10110 while Present (It.Typ) loop
10111 if (Is_Array_Type (It.Typ)
10112 and then Covers (Typ, It.Typ))
10113 or else (Is_Access_Type (It.Typ)
10114 and then Is_Array_Type (Designated_Type (It.Typ))
10115 and then Covers (Typ, Designated_Type (It.Typ)))
10116 then
10117 if Found then
10118 It := Disambiguate (P, I1, I, Any_Type);
10119
10120 if It = No_Interp then
10121 Error_Msg_N ("ambiguous prefix for slicing", N);
10122 Set_Etype (N, Typ);
10123 return;
10124 else
10125 Found := True;
10126 Array_Type := It.Typ;
10127 I1 := I;
10128 end if;
10129 else
10130 Found := True;
10131 Array_Type := It.Typ;
10132 I1 := I;
10133 end if;
10134 end if;
10135
10136 Get_Next_Interp (I, It);
10137 end loop;
10138 end;
10139
10140 else
10141 Array_Type := Etype (Name);
10142 end if;
10143
10144 Resolve (Name, Array_Type);
10145
10146 if Is_Access_Type (Array_Type) then
10147 Apply_Access_Check (N);
10148 Array_Type := Designated_Type (Array_Type);
10149
10150 -- If the prefix is an access to an unconstrained array, we must use
10151 -- the actual subtype of the object to perform the index checks. The
10152 -- object denoted by the prefix is implicit in the node, so we build
10153 -- an explicit representation for it in order to compute the actual
10154 -- subtype.
10155
10156 if not Is_Constrained (Array_Type) then
10157 Remove_Side_Effects (Prefix (N));
10158
10159 declare
10160 Obj : constant Node_Id :=
10161 Make_Explicit_Dereference (Sloc (N),
10162 Prefix => New_Copy_Tree (Prefix (N)));
10163 begin
10164 Set_Etype (Obj, Array_Type);
10165 Set_Parent (Obj, Parent (N));
10166 Array_Type := Get_Actual_Subtype (Obj);
10167 end;
10168 end if;
10169
10170 elsif Is_Entity_Name (Name)
10171 or else Nkind (Name) = N_Explicit_Dereference
10172 or else (Nkind (Name) = N_Function_Call
10173 and then not Is_Constrained (Etype (Name)))
10174 then
10175 Array_Type := Get_Actual_Subtype (Name);
10176
10177 -- If the name is a selected component that depends on discriminants,
10178 -- build an actual subtype for it. This can happen only when the name
10179 -- itself is overloaded; otherwise the actual subtype is created when
10180 -- the selected component is analyzed.
10181
10182 elsif Nkind (Name) = N_Selected_Component
10183 and then Full_Analysis
10184 and then Depends_On_Discriminant (First_Index (Array_Type))
10185 then
10186 declare
10187 Act_Decl : constant Node_Id :=
10188 Build_Actual_Subtype_Of_Component (Array_Type, Name);
10189 begin
10190 Insert_Action (N, Act_Decl);
10191 Array_Type := Defining_Identifier (Act_Decl);
10192 end;
10193
10194 -- Maybe this should just be "else", instead of checking for the
10195 -- specific case of slice??? This is needed for the case where the
10196 -- prefix is an Image attribute, which gets expanded to a slice, and so
10197 -- has a constrained subtype which we want to use for the slice range
10198 -- check applied below (the range check won't get done if the
10199 -- unconstrained subtype of the 'Image is used).
10200
10201 elsif Nkind (Name) = N_Slice then
10202 Array_Type := Etype (Name);
10203 end if;
10204
10205 -- Obtain the type of the array index
10206
10207 if Ekind (Array_Type) = E_String_Literal_Subtype then
10208 Index_Type := Etype (String_Literal_Low_Bound (Array_Type));
10209 else
10210 Index_Type := Etype (First_Index (Array_Type));
10211 end if;
10212
10213 -- If name was overloaded, set slice type correctly now
10214
10215 Set_Etype (N, Array_Type);
10216
10217 -- Handle the generation of a range check that compares the array index
10218 -- against the discrete_range. The check is not applied to internally
10219 -- built nodes associated with the expansion of dispatch tables. Check
10220 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10221 -- the unit.
10222
10223 if Tagged_Type_Expansion
10224 and then RTU_Loaded (Ada_Tags)
10225 and then Nkind (Prefix (N)) = N_Selected_Component
10226 and then Present (Entity (Selector_Name (Prefix (N))))
10227 and then Entity (Selector_Name (Prefix (N))) =
10228 RTE_Record_Component (RE_Prims_Ptr)
10229 then
10230 null;
10231
10232 -- The discrete_range is specified by a subtype indication. Create a
10233 -- shallow copy and inherit the type, parent and source location from
10234 -- the discrete_range. This ensures that the range check is inserted
10235 -- relative to the slice and that the runtime exception points to the
10236 -- proper construct.
10237
10238 elsif Is_Entity_Name (Drange) then
10239 Dexpr := New_Copy (Scalar_Range (Entity (Drange)));
10240
10241 Set_Etype (Dexpr, Etype (Drange));
10242 Set_Parent (Dexpr, Parent (Drange));
10243 Set_Sloc (Dexpr, Sloc (Drange));
10244
10245 -- The discrete_range is a regular range. Resolve the bounds and remove
10246 -- their side effects.
10247
10248 else
10249 Resolve (Drange, Base_Type (Index_Type));
10250
10251 if Nkind (Drange) = N_Range then
10252 Force_Evaluation (Low_Bound (Drange));
10253 Force_Evaluation (High_Bound (Drange));
10254
10255 Dexpr := Drange;
10256 end if;
10257 end if;
10258
10259 if Present (Dexpr) then
10260 Apply_Range_Check (Dexpr, Index_Type);
10261 end if;
10262
10263 Set_Slice_Subtype (N);
10264
10265 -- Check bad use of type with predicates
10266
10267 declare
10268 Subt : Entity_Id;
10269
10270 begin
10271 if Nkind (Drange) = N_Subtype_Indication
10272 and then Has_Predicates (Entity (Subtype_Mark (Drange)))
10273 then
10274 Subt := Entity (Subtype_Mark (Drange));
10275 else
10276 Subt := Etype (Drange);
10277 end if;
10278
10279 if Has_Predicates (Subt) then
10280 Bad_Predicated_Subtype_Use
10281 ("subtype& has predicate, not allowed in slice", Drange, Subt);
10282 end if;
10283 end;
10284
10285 -- Otherwise here is where we check suspicious indexes
10286
10287 if Nkind (Drange) = N_Range then
10288 Warn_On_Suspicious_Index (Name, Low_Bound (Drange));
10289 Warn_On_Suspicious_Index (Name, High_Bound (Drange));
10290 end if;
10291
10292 Analyze_Dimension (N);
10293 Eval_Slice (N);
10294 end Resolve_Slice;
10295
10296 ----------------------------
10297 -- Resolve_String_Literal --
10298 ----------------------------
10299
10300 procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id) is
10301 C_Typ : constant Entity_Id := Component_Type (Typ);
10302 R_Typ : constant Entity_Id := Root_Type (C_Typ);
10303 Loc : constant Source_Ptr := Sloc (N);
10304 Str : constant String_Id := Strval (N);
10305 Strlen : constant Nat := String_Length (Str);
10306 Subtype_Id : Entity_Id;
10307 Need_Check : Boolean;
10308
10309 begin
10310 -- For a string appearing in a concatenation, defer creation of the
10311 -- string_literal_subtype until the end of the resolution of the
10312 -- concatenation, because the literal may be constant-folded away. This
10313 -- is a useful optimization for long concatenation expressions.
10314
10315 -- If the string is an aggregate built for a single character (which
10316 -- happens in a non-static context) or a is null string to which special
10317 -- checks may apply, we build the subtype. Wide strings must also get a
10318 -- string subtype if they come from a one character aggregate. Strings
10319 -- generated by attributes might be static, but it is often hard to
10320 -- determine whether the enclosing context is static, so we generate
10321 -- subtypes for them as well, thus losing some rarer optimizations ???
10322 -- Same for strings that come from a static conversion.
10323
10324 Need_Check :=
10325 (Strlen = 0 and then Typ /= Standard_String)
10326 or else Nkind (Parent (N)) /= N_Op_Concat
10327 or else (N /= Left_Opnd (Parent (N))
10328 and then N /= Right_Opnd (Parent (N)))
10329 or else ((Typ = Standard_Wide_String
10330 or else Typ = Standard_Wide_Wide_String)
10331 and then Nkind (Original_Node (N)) /= N_String_Literal);
10332
10333 -- If the resolving type is itself a string literal subtype, we can just
10334 -- reuse it, since there is no point in creating another.
10335
10336 if Ekind (Typ) = E_String_Literal_Subtype then
10337 Subtype_Id := Typ;
10338
10339 elsif Nkind (Parent (N)) = N_Op_Concat
10340 and then not Need_Check
10341 and then not Nkind_In (Original_Node (N), N_Character_Literal,
10342 N_Attribute_Reference,
10343 N_Qualified_Expression,
10344 N_Type_Conversion)
10345 then
10346 Subtype_Id := Typ;
10347
10348 -- Do not generate a string literal subtype for the default expression
10349 -- of a formal parameter in GNATprove mode. This is because the string
10350 -- subtype is associated with the freezing actions of the subprogram,
10351 -- however freezing is disabled in GNATprove mode and as a result the
10352 -- subtype is unavailable.
10353
10354 elsif GNATprove_Mode
10355 and then Nkind (Parent (N)) = N_Parameter_Specification
10356 then
10357 Subtype_Id := Typ;
10358
10359 -- Otherwise we must create a string literal subtype. Note that the
10360 -- whole idea of string literal subtypes is simply to avoid the need
10361 -- for building a full fledged array subtype for each literal.
10362
10363 else
10364 Set_String_Literal_Subtype (N, Typ);
10365 Subtype_Id := Etype (N);
10366 end if;
10367
10368 if Nkind (Parent (N)) /= N_Op_Concat
10369 or else Need_Check
10370 then
10371 Set_Etype (N, Subtype_Id);
10372 Eval_String_Literal (N);
10373 end if;
10374
10375 if Is_Limited_Composite (Typ)
10376 or else Is_Private_Composite (Typ)
10377 then
10378 Error_Msg_N ("string literal not available for private array", N);
10379 Set_Etype (N, Any_Type);
10380 return;
10381 end if;
10382
10383 -- The validity of a null string has been checked in the call to
10384 -- Eval_String_Literal.
10385
10386 if Strlen = 0 then
10387 return;
10388
10389 -- Always accept string literal with component type Any_Character, which
10390 -- occurs in error situations and in comparisons of literals, both of
10391 -- which should accept all literals.
10392
10393 elsif R_Typ = Any_Character then
10394 return;
10395
10396 -- If the type is bit-packed, then we always transform the string
10397 -- literal into a full fledged aggregate.
10398
10399 elsif Is_Bit_Packed_Array (Typ) then
10400 null;
10401
10402 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10403
10404 else
10405 -- For Standard.Wide_Wide_String, or any other type whose component
10406 -- type is Standard.Wide_Wide_Character, we know that all the
10407 -- characters in the string must be acceptable, since the parser
10408 -- accepted the characters as valid character literals.
10409
10410 if R_Typ = Standard_Wide_Wide_Character then
10411 null;
10412
10413 -- For the case of Standard.String, or any other type whose component
10414 -- type is Standard.Character, we must make sure that there are no
10415 -- wide characters in the string, i.e. that it is entirely composed
10416 -- of characters in range of type Character.
10417
10418 -- If the string literal is the result of a static concatenation, the
10419 -- test has already been performed on the components, and need not be
10420 -- repeated.
10421
10422 elsif R_Typ = Standard_Character
10423 and then Nkind (Original_Node (N)) /= N_Op_Concat
10424 then
10425 for J in 1 .. Strlen loop
10426 if not In_Character_Range (Get_String_Char (Str, J)) then
10427
10428 -- If we are out of range, post error. This is one of the
10429 -- very few places that we place the flag in the middle of
10430 -- a token, right under the offending wide character. Not
10431 -- quite clear if this is right wrt wide character encoding
10432 -- sequences, but it's only an error message.
10433
10434 Error_Msg
10435 ("literal out of range of type Standard.Character",
10436 Source_Ptr (Int (Loc) + J));
10437 return;
10438 end if;
10439 end loop;
10440
10441 -- For the case of Standard.Wide_String, or any other type whose
10442 -- component type is Standard.Wide_Character, we must make sure that
10443 -- there are no wide characters in the string, i.e. that it is
10444 -- entirely composed of characters in range of type Wide_Character.
10445
10446 -- If the string literal is the result of a static concatenation,
10447 -- the test has already been performed on the components, and need
10448 -- not be repeated.
10449
10450 elsif R_Typ = Standard_Wide_Character
10451 and then Nkind (Original_Node (N)) /= N_Op_Concat
10452 then
10453 for J in 1 .. Strlen loop
10454 if not In_Wide_Character_Range (Get_String_Char (Str, J)) then
10455
10456 -- If we are out of range, post error. This is one of the
10457 -- very few places that we place the flag in the middle of
10458 -- a token, right under the offending wide character.
10459
10460 -- This is not quite right, because characters in general
10461 -- will take more than one character position ???
10462
10463 Error_Msg
10464 ("literal out of range of type Standard.Wide_Character",
10465 Source_Ptr (Int (Loc) + J));
10466 return;
10467 end if;
10468 end loop;
10469
10470 -- If the root type is not a standard character, then we will convert
10471 -- the string into an aggregate and will let the aggregate code do
10472 -- the checking. Standard Wide_Wide_Character is also OK here.
10473
10474 else
10475 null;
10476 end if;
10477
10478 -- See if the component type of the array corresponding to the string
10479 -- has compile time known bounds. If yes we can directly check
10480 -- whether the evaluation of the string will raise constraint error.
10481 -- Otherwise we need to transform the string literal into the
10482 -- corresponding character aggregate and let the aggregate code do
10483 -- the checking.
10484
10485 if Is_Standard_Character_Type (R_Typ) then
10486
10487 -- Check for the case of full range, where we are definitely OK
10488
10489 if Component_Type (Typ) = Base_Type (Component_Type (Typ)) then
10490 return;
10491 end if;
10492
10493 -- Here the range is not the complete base type range, so check
10494
10495 declare
10496 Comp_Typ_Lo : constant Node_Id :=
10497 Type_Low_Bound (Component_Type (Typ));
10498 Comp_Typ_Hi : constant Node_Id :=
10499 Type_High_Bound (Component_Type (Typ));
10500
10501 Char_Val : Uint;
10502
10503 begin
10504 if Compile_Time_Known_Value (Comp_Typ_Lo)
10505 and then Compile_Time_Known_Value (Comp_Typ_Hi)
10506 then
10507 for J in 1 .. Strlen loop
10508 Char_Val := UI_From_Int (Int (Get_String_Char (Str, J)));
10509
10510 if Char_Val < Expr_Value (Comp_Typ_Lo)
10511 or else Char_Val > Expr_Value (Comp_Typ_Hi)
10512 then
10513 Apply_Compile_Time_Constraint_Error
10514 (N, "character out of range??",
10515 CE_Range_Check_Failed,
10516 Loc => Source_Ptr (Int (Loc) + J));
10517 end if;
10518 end loop;
10519
10520 return;
10521 end if;
10522 end;
10523 end if;
10524 end if;
10525
10526 -- If we got here we meed to transform the string literal into the
10527 -- equivalent qualified positional array aggregate. This is rather
10528 -- heavy artillery for this situation, but it is hard work to avoid.
10529
10530 declare
10531 Lits : constant List_Id := New_List;
10532 P : Source_Ptr := Loc + 1;
10533 C : Char_Code;
10534
10535 begin
10536 -- Build the character literals, we give them source locations that
10537 -- correspond to the string positions, which is a bit tricky given
10538 -- the possible presence of wide character escape sequences.
10539
10540 for J in 1 .. Strlen loop
10541 C := Get_String_Char (Str, J);
10542 Set_Character_Literal_Name (C);
10543
10544 Append_To (Lits,
10545 Make_Character_Literal (P,
10546 Chars => Name_Find,
10547 Char_Literal_Value => UI_From_CC (C)));
10548
10549 if In_Character_Range (C) then
10550 P := P + 1;
10551
10552 -- Should we have a call to Skip_Wide here ???
10553
10554 -- ??? else
10555 -- Skip_Wide (P);
10556
10557 end if;
10558 end loop;
10559
10560 Rewrite (N,
10561 Make_Qualified_Expression (Loc,
10562 Subtype_Mark => New_Occurrence_Of (Typ, Loc),
10563 Expression =>
10564 Make_Aggregate (Loc, Expressions => Lits)));
10565
10566 Analyze_And_Resolve (N, Typ);
10567 end;
10568 end Resolve_String_Literal;
10569
10570 -----------------------------
10571 -- Resolve_Type_Conversion --
10572 -----------------------------
10573
10574 procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id) is
10575 Conv_OK : constant Boolean := Conversion_OK (N);
10576 Operand : constant Node_Id := Expression (N);
10577 Operand_Typ : constant Entity_Id := Etype (Operand);
10578 Target_Typ : constant Entity_Id := Etype (N);
10579 Rop : Node_Id;
10580 Orig_N : Node_Id;
10581 Orig_T : Node_Id;
10582
10583 Test_Redundant : Boolean := Warn_On_Redundant_Constructs;
10584 -- Set to False to suppress cases where we want to suppress the test
10585 -- for redundancy to avoid possible false positives on this warning.
10586
10587 begin
10588 if not Conv_OK
10589 and then not Valid_Conversion (N, Target_Typ, Operand)
10590 then
10591 return;
10592 end if;
10593
10594 -- If the Operand Etype is Universal_Fixed, then the conversion is
10595 -- never redundant. We need this check because by the time we have
10596 -- finished the rather complex transformation, the conversion looks
10597 -- redundant when it is not.
10598
10599 if Operand_Typ = Universal_Fixed then
10600 Test_Redundant := False;
10601
10602 -- If the operand is marked as Any_Fixed, then special processing is
10603 -- required. This is also a case where we suppress the test for a
10604 -- redundant conversion, since most certainly it is not redundant.
10605
10606 elsif Operand_Typ = Any_Fixed then
10607 Test_Redundant := False;
10608
10609 -- Mixed-mode operation involving a literal. Context must be a fixed
10610 -- type which is applied to the literal subsequently.
10611
10612 if Is_Fixed_Point_Type (Typ) then
10613 Set_Etype (Operand, Universal_Real);
10614
10615 elsif Is_Numeric_Type (Typ)
10616 and then Nkind_In (Operand, N_Op_Multiply, N_Op_Divide)
10617 and then (Etype (Right_Opnd (Operand)) = Universal_Real
10618 or else
10619 Etype (Left_Opnd (Operand)) = Universal_Real)
10620 then
10621 -- Return if expression is ambiguous
10622
10623 if Unique_Fixed_Point_Type (N) = Any_Type then
10624 return;
10625
10626 -- If nothing else, the available fixed type is Duration
10627
10628 else
10629 Set_Etype (Operand, Standard_Duration);
10630 end if;
10631
10632 -- Resolve the real operand with largest available precision
10633
10634 if Etype (Right_Opnd (Operand)) = Universal_Real then
10635 Rop := New_Copy_Tree (Right_Opnd (Operand));
10636 else
10637 Rop := New_Copy_Tree (Left_Opnd (Operand));
10638 end if;
10639
10640 Resolve (Rop, Universal_Real);
10641
10642 -- If the operand is a literal (it could be a non-static and
10643 -- illegal exponentiation) check whether the use of Duration
10644 -- is potentially inaccurate.
10645
10646 if Nkind (Rop) = N_Real_Literal
10647 and then Realval (Rop) /= Ureal_0
10648 and then abs (Realval (Rop)) < Delta_Value (Standard_Duration)
10649 then
10650 Error_Msg_N
10651 ("??universal real operand can only "
10652 & "be interpreted as Duration!", Rop);
10653 Error_Msg_N
10654 ("\??precision will be lost in the conversion!", Rop);
10655 end if;
10656
10657 elsif Is_Numeric_Type (Typ)
10658 and then Nkind (Operand) in N_Op
10659 and then Unique_Fixed_Point_Type (N) /= Any_Type
10660 then
10661 Set_Etype (Operand, Standard_Duration);
10662
10663 else
10664 Error_Msg_N ("invalid context for mixed mode operation", N);
10665 Set_Etype (Operand, Any_Type);
10666 return;
10667 end if;
10668 end if;
10669
10670 Resolve (Operand);
10671
10672 -- In SPARK, a type conversion between array types should be restricted
10673 -- to types which have matching static bounds.
10674
10675 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10676 -- operation if not needed.
10677
10678 if Restriction_Check_Required (SPARK_05)
10679 and then Is_Array_Type (Target_Typ)
10680 and then Is_Array_Type (Operand_Typ)
10681 and then Operand_Typ /= Any_Composite -- or else Operand in error
10682 and then not Matching_Static_Array_Bounds (Target_Typ, Operand_Typ)
10683 then
10684 Check_SPARK_05_Restriction
10685 ("array types should have matching static bounds", N);
10686 end if;
10687
10688 -- In formal mode, the operand of an ancestor type conversion must be an
10689 -- object (not an expression).
10690
10691 if Is_Tagged_Type (Target_Typ)
10692 and then not Is_Class_Wide_Type (Target_Typ)
10693 and then Is_Tagged_Type (Operand_Typ)
10694 and then not Is_Class_Wide_Type (Operand_Typ)
10695 and then Is_Ancestor (Target_Typ, Operand_Typ)
10696 and then not Is_SPARK_05_Object_Reference (Operand)
10697 then
10698 Check_SPARK_05_Restriction ("object required", Operand);
10699 end if;
10700
10701 Analyze_Dimension (N);
10702
10703 -- Note: we do the Eval_Type_Conversion call before applying the
10704 -- required checks for a subtype conversion. This is important, since
10705 -- both are prepared under certain circumstances to change the type
10706 -- conversion to a constraint error node, but in the case of
10707 -- Eval_Type_Conversion this may reflect an illegality in the static
10708 -- case, and we would miss the illegality (getting only a warning
10709 -- message), if we applied the type conversion checks first.
10710
10711 Eval_Type_Conversion (N);
10712
10713 -- Even when evaluation is not possible, we may be able to simplify the
10714 -- conversion or its expression. This needs to be done before applying
10715 -- checks, since otherwise the checks may use the original expression
10716 -- and defeat the simplifications. This is specifically the case for
10717 -- elimination of the floating-point Truncation attribute in
10718 -- float-to-int conversions.
10719
10720 Simplify_Type_Conversion (N);
10721
10722 -- If after evaluation we still have a type conversion, then we may need
10723 -- to apply checks required for a subtype conversion.
10724
10725 -- Skip these type conversion checks if universal fixed operands
10726 -- operands involved, since range checks are handled separately for
10727 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10728
10729 if Nkind (N) = N_Type_Conversion
10730 and then not Is_Generic_Type (Root_Type (Target_Typ))
10731 and then Target_Typ /= Universal_Fixed
10732 and then Operand_Typ /= Universal_Fixed
10733 then
10734 Apply_Type_Conversion_Checks (N);
10735 end if;
10736
10737 -- Issue warning for conversion of simple object to its own type. We
10738 -- have to test the original nodes, since they may have been rewritten
10739 -- by various optimizations.
10740
10741 Orig_N := Original_Node (N);
10742
10743 -- Here we test for a redundant conversion if the warning mode is
10744 -- active (and was not locally reset), and we have a type conversion
10745 -- from source not appearing in a generic instance.
10746
10747 if Test_Redundant
10748 and then Nkind (Orig_N) = N_Type_Conversion
10749 and then Comes_From_Source (Orig_N)
10750 and then not In_Instance
10751 then
10752 Orig_N := Original_Node (Expression (Orig_N));
10753 Orig_T := Target_Typ;
10754
10755 -- If the node is part of a larger expression, the Target_Type
10756 -- may not be the original type of the node if the context is a
10757 -- condition. Recover original type to see if conversion is needed.
10758
10759 if Is_Boolean_Type (Orig_T)
10760 and then Nkind (Parent (N)) in N_Op
10761 then
10762 Orig_T := Etype (Parent (N));
10763 end if;
10764
10765 -- If we have an entity name, then give the warning if the entity
10766 -- is the right type, or if it is a loop parameter covered by the
10767 -- original type (that's needed because loop parameters have an
10768 -- odd subtype coming from the bounds).
10769
10770 if (Is_Entity_Name (Orig_N)
10771 and then
10772 (Etype (Entity (Orig_N)) = Orig_T
10773 or else
10774 (Ekind (Entity (Orig_N)) = E_Loop_Parameter
10775 and then Covers (Orig_T, Etype (Entity (Orig_N))))))
10776
10777 -- If not an entity, then type of expression must match
10778
10779 or else Etype (Orig_N) = Orig_T
10780 then
10781 -- One more check, do not give warning if the analyzed conversion
10782 -- has an expression with non-static bounds, and the bounds of the
10783 -- target are static. This avoids junk warnings in cases where the
10784 -- conversion is necessary to establish staticness, for example in
10785 -- a case statement.
10786
10787 if not Is_OK_Static_Subtype (Operand_Typ)
10788 and then Is_OK_Static_Subtype (Target_Typ)
10789 then
10790 null;
10791
10792 -- Finally, if this type conversion occurs in a context requiring
10793 -- a prefix, and the expression is a qualified expression then the
10794 -- type conversion is not redundant, since a qualified expression
10795 -- is not a prefix, whereas a type conversion is. For example, "X
10796 -- := T'(Funx(...)).Y;" is illegal because a selected component
10797 -- requires a prefix, but a type conversion makes it legal: "X :=
10798 -- T(T'(Funx(...))).Y;"
10799
10800 -- In Ada 2012, a qualified expression is a name, so this idiom is
10801 -- no longer needed, but we still suppress the warning because it
10802 -- seems unfriendly for warnings to pop up when you switch to the
10803 -- newer language version.
10804
10805 elsif Nkind (Orig_N) = N_Qualified_Expression
10806 and then Nkind_In (Parent (N), N_Attribute_Reference,
10807 N_Indexed_Component,
10808 N_Selected_Component,
10809 N_Slice,
10810 N_Explicit_Dereference)
10811 then
10812 null;
10813
10814 -- Never warn on conversion to Long_Long_Integer'Base since
10815 -- that is most likely an artifact of the extended overflow
10816 -- checking and comes from complex expanded code.
10817
10818 elsif Orig_T = Base_Type (Standard_Long_Long_Integer) then
10819 null;
10820
10821 -- Here we give the redundant conversion warning. If it is an
10822 -- entity, give the name of the entity in the message. If not,
10823 -- just mention the expression.
10824
10825 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10826
10827 else
10828 if Is_Entity_Name (Orig_N) then
10829 Error_Msg_Node_2 := Orig_T;
10830 Error_Msg_NE -- CODEFIX
10831 ("??redundant conversion, & is of type &!",
10832 N, Entity (Orig_N));
10833 else
10834 Error_Msg_NE
10835 ("??redundant conversion, expression is of type&!",
10836 N, Orig_T);
10837 end if;
10838 end if;
10839 end if;
10840 end if;
10841
10842 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10843 -- No need to perform any interface conversion if the type of the
10844 -- expression coincides with the target type.
10845
10846 if Ada_Version >= Ada_2005
10847 and then Expander_Active
10848 and then Operand_Typ /= Target_Typ
10849 then
10850 declare
10851 Opnd : Entity_Id := Operand_Typ;
10852 Target : Entity_Id := Target_Typ;
10853
10854 begin
10855 -- If the type of the operand is a limited view, use nonlimited
10856 -- view when available. If it is a class-wide type, recover the
10857 -- class-wide type of the nonlimited view.
10858
10859 if From_Limited_With (Opnd)
10860 and then Has_Non_Limited_View (Opnd)
10861 then
10862 Opnd := Non_Limited_View (Opnd);
10863 Set_Etype (Expression (N), Opnd);
10864 end if;
10865
10866 if Is_Access_Type (Opnd) then
10867 Opnd := Designated_Type (Opnd);
10868 end if;
10869
10870 if Is_Access_Type (Target_Typ) then
10871 Target := Designated_Type (Target);
10872 end if;
10873
10874 if Opnd = Target then
10875 null;
10876
10877 -- Conversion from interface type
10878
10879 elsif Is_Interface (Opnd) then
10880
10881 -- Ada 2005 (AI-217): Handle entities from limited views
10882
10883 if From_Limited_With (Opnd) then
10884 Error_Msg_Qual_Level := 99;
10885 Error_Msg_NE -- CODEFIX
10886 ("missing WITH clause on package &", N,
10887 Cunit_Entity (Get_Source_Unit (Base_Type (Opnd))));
10888 Error_Msg_N
10889 ("type conversions require visibility of the full view",
10890 N);
10891
10892 elsif From_Limited_With (Target)
10893 and then not
10894 (Is_Access_Type (Target_Typ)
10895 and then Present (Non_Limited_View (Etype (Target))))
10896 then
10897 Error_Msg_Qual_Level := 99;
10898 Error_Msg_NE -- CODEFIX
10899 ("missing WITH clause on package &", N,
10900 Cunit_Entity (Get_Source_Unit (Base_Type (Target))));
10901 Error_Msg_N
10902 ("type conversions require visibility of the full view",
10903 N);
10904
10905 else
10906 Expand_Interface_Conversion (N);
10907 end if;
10908
10909 -- Conversion to interface type
10910
10911 elsif Is_Interface (Target) then
10912
10913 -- Handle subtypes
10914
10915 if Ekind_In (Opnd, E_Protected_Subtype, E_Task_Subtype) then
10916 Opnd := Etype (Opnd);
10917 end if;
10918
10919 if Is_Class_Wide_Type (Opnd)
10920 or else Interface_Present_In_Ancestor
10921 (Typ => Opnd,
10922 Iface => Target)
10923 then
10924 Expand_Interface_Conversion (N);
10925 else
10926 Error_Msg_Name_1 := Chars (Etype (Target));
10927 Error_Msg_Name_2 := Chars (Opnd);
10928 Error_Msg_N
10929 ("wrong interface conversion (% is not a progenitor "
10930 & "of %)", N);
10931 end if;
10932 end if;
10933 end;
10934 end if;
10935
10936 -- Ada 2012: if target type has predicates, the result requires a
10937 -- predicate check. If the context is a call to another predicate
10938 -- check we must prevent infinite recursion.
10939
10940 if Has_Predicates (Target_Typ) then
10941 if Nkind (Parent (N)) = N_Function_Call
10942 and then Present (Name (Parent (N)))
10943 and then (Is_Predicate_Function (Entity (Name (Parent (N))))
10944 or else
10945 Is_Predicate_Function_M (Entity (Name (Parent (N)))))
10946 then
10947 null;
10948
10949 else
10950 Apply_Predicate_Check (N, Target_Typ);
10951 end if;
10952 end if;
10953
10954 -- If at this stage we have a real to integer conversion, make sure
10955 -- that the Do_Range_Check flag is set, because such conversions in
10956 -- general need a range check. We only need this if expansion is off
10957 -- or we are in GNATProve mode.
10958
10959 if Nkind (N) = N_Type_Conversion
10960 and then (GNATprove_Mode or not Expander_Active)
10961 and then Is_Integer_Type (Target_Typ)
10962 and then Is_Real_Type (Operand_Typ)
10963 then
10964 Set_Do_Range_Check (Operand);
10965 end if;
10966
10967 -- Generating C code a type conversion of an access to constrained
10968 -- array type to access to unconstrained array type involves building
10969 -- a fat pointer which in general cannot be generated on the fly. We
10970 -- remove side effects in order to store the result of the conversion
10971 -- into a temporary.
10972
10973 if Generate_C_Code
10974 and then Nkind (N) = N_Type_Conversion
10975 and then Nkind (Parent (N)) /= N_Object_Declaration
10976 and then Is_Access_Type (Etype (N))
10977 and then Is_Array_Type (Designated_Type (Etype (N)))
10978 and then not Is_Constrained (Designated_Type (Etype (N)))
10979 and then Is_Constrained (Designated_Type (Etype (Expression (N))))
10980 then
10981 Remove_Side_Effects (N);
10982 end if;
10983 end Resolve_Type_Conversion;
10984
10985 ----------------------
10986 -- Resolve_Unary_Op --
10987 ----------------------
10988
10989 procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id) is
10990 B_Typ : constant Entity_Id := Base_Type (Typ);
10991 R : constant Node_Id := Right_Opnd (N);
10992 OK : Boolean;
10993 Lo : Uint;
10994 Hi : Uint;
10995
10996 begin
10997 if Is_Modular_Integer_Type (Typ) and then Nkind (N) /= N_Op_Not then
10998 Error_Msg_Name_1 := Chars (Typ);
10999 Check_SPARK_05_Restriction
11000 ("unary operator not defined for modular type%", N);
11001 end if;
11002
11003 -- Deal with intrinsic unary operators
11004
11005 if Comes_From_Source (N)
11006 and then Ekind (Entity (N)) = E_Function
11007 and then Is_Imported (Entity (N))
11008 and then Is_Intrinsic_Subprogram (Entity (N))
11009 then
11010 Resolve_Intrinsic_Unary_Operator (N, Typ);
11011 return;
11012 end if;
11013
11014 -- Deal with universal cases
11015
11016 if Etype (R) = Universal_Integer
11017 or else
11018 Etype (R) = Universal_Real
11019 then
11020 Check_For_Visible_Operator (N, B_Typ);
11021 end if;
11022
11023 Set_Etype (N, B_Typ);
11024 Resolve (R, B_Typ);
11025
11026 -- Generate warning for expressions like abs (x mod 2)
11027
11028 if Warn_On_Redundant_Constructs
11029 and then Nkind (N) = N_Op_Abs
11030 then
11031 Determine_Range (Right_Opnd (N), OK, Lo, Hi);
11032
11033 if OK and then Hi >= Lo and then Lo >= 0 then
11034 Error_Msg_N -- CODEFIX
11035 ("?r?abs applied to known non-negative value has no effect", N);
11036 end if;
11037 end if;
11038
11039 -- Deal with reference generation
11040
11041 Check_Unset_Reference (R);
11042 Generate_Operator_Reference (N, B_Typ);
11043 Analyze_Dimension (N);
11044 Eval_Unary_Op (N);
11045
11046 -- Set overflow checking bit. Much cleverer code needed here eventually
11047 -- and perhaps the Resolve routines should be separated for the various
11048 -- arithmetic operations, since they will need different processing ???
11049
11050 if Nkind (N) in N_Op then
11051 if not Overflow_Checks_Suppressed (Etype (N)) then
11052 Enable_Overflow_Check (N);
11053 end if;
11054 end if;
11055
11056 -- Generate warning for expressions like -5 mod 3 for integers. No need
11057 -- to worry in the floating-point case, since parens do not affect the
11058 -- result so there is no point in giving in a warning.
11059
11060 declare
11061 Norig : constant Node_Id := Original_Node (N);
11062 Rorig : Node_Id;
11063 Val : Uint;
11064 HB : Uint;
11065 LB : Uint;
11066 Lval : Uint;
11067 Opnd : Node_Id;
11068
11069 begin
11070 if Warn_On_Questionable_Missing_Parens
11071 and then Comes_From_Source (Norig)
11072 and then Is_Integer_Type (Typ)
11073 and then Nkind (Norig) = N_Op_Minus
11074 then
11075 Rorig := Original_Node (Right_Opnd (Norig));
11076
11077 -- We are looking for cases where the right operand is not
11078 -- parenthesized, and is a binary operator, multiply, divide, or
11079 -- mod. These are the cases where the grouping can affect results.
11080
11081 if Paren_Count (Rorig) = 0
11082 and then Nkind_In (Rorig, N_Op_Mod, N_Op_Multiply, N_Op_Divide)
11083 then
11084 -- For mod, we always give the warning, since the value is
11085 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11086 -- -(5 mod 315)). But for the other cases, the only concern is
11087 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11088 -- overflows, but (-2) * 64 does not). So we try to give the
11089 -- message only when overflow is possible.
11090
11091 if Nkind (Rorig) /= N_Op_Mod
11092 and then Compile_Time_Known_Value (R)
11093 then
11094 Val := Expr_Value (R);
11095
11096 if Compile_Time_Known_Value (Type_High_Bound (Typ)) then
11097 HB := Expr_Value (Type_High_Bound (Typ));
11098 else
11099 HB := Expr_Value (Type_High_Bound (Base_Type (Typ)));
11100 end if;
11101
11102 if Compile_Time_Known_Value (Type_Low_Bound (Typ)) then
11103 LB := Expr_Value (Type_Low_Bound (Typ));
11104 else
11105 LB := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
11106 end if;
11107
11108 -- Note that the test below is deliberately excluding the
11109 -- largest negative number, since that is a potentially
11110 -- troublesome case (e.g. -2 * x, where the result is the
11111 -- largest negative integer has an overflow with 2 * x).
11112
11113 if Val > LB and then Val <= HB then
11114 return;
11115 end if;
11116 end if;
11117
11118 -- For the multiplication case, the only case we have to worry
11119 -- about is when (-a)*b is exactly the largest negative number
11120 -- so that -(a*b) can cause overflow. This can only happen if
11121 -- a is a power of 2, and more generally if any operand is a
11122 -- constant that is not a power of 2, then the parentheses
11123 -- cannot affect whether overflow occurs. We only bother to
11124 -- test the left most operand
11125
11126 -- Loop looking at left operands for one that has known value
11127
11128 Opnd := Rorig;
11129 Opnd_Loop : while Nkind (Opnd) = N_Op_Multiply loop
11130 if Compile_Time_Known_Value (Left_Opnd (Opnd)) then
11131 Lval := UI_Abs (Expr_Value (Left_Opnd (Opnd)));
11132
11133 -- Operand value of 0 or 1 skips warning
11134
11135 if Lval <= 1 then
11136 return;
11137
11138 -- Otherwise check power of 2, if power of 2, warn, if
11139 -- anything else, skip warning.
11140
11141 else
11142 while Lval /= 2 loop
11143 if Lval mod 2 = 1 then
11144 return;
11145 else
11146 Lval := Lval / 2;
11147 end if;
11148 end loop;
11149
11150 exit Opnd_Loop;
11151 end if;
11152 end if;
11153
11154 -- Keep looking at left operands
11155
11156 Opnd := Left_Opnd (Opnd);
11157 end loop Opnd_Loop;
11158
11159 -- For rem or "/" we can only have a problematic situation
11160 -- if the divisor has a value of minus one or one. Otherwise
11161 -- overflow is impossible (divisor > 1) or we have a case of
11162 -- division by zero in any case.
11163
11164 if Nkind_In (Rorig, N_Op_Divide, N_Op_Rem)
11165 and then Compile_Time_Known_Value (Right_Opnd (Rorig))
11166 and then UI_Abs (Expr_Value (Right_Opnd (Rorig))) /= 1
11167 then
11168 return;
11169 end if;
11170
11171 -- If we fall through warning should be issued
11172
11173 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11174
11175 Error_Msg_N
11176 ("??unary minus expression should be parenthesized here!", N);
11177 end if;
11178 end if;
11179 end;
11180 end Resolve_Unary_Op;
11181
11182 ----------------------------------
11183 -- Resolve_Unchecked_Expression --
11184 ----------------------------------
11185
11186 procedure Resolve_Unchecked_Expression
11187 (N : Node_Id;
11188 Typ : Entity_Id)
11189 is
11190 begin
11191 Resolve (Expression (N), Typ, Suppress => All_Checks);
11192 Set_Etype (N, Typ);
11193 end Resolve_Unchecked_Expression;
11194
11195 ---------------------------------------
11196 -- Resolve_Unchecked_Type_Conversion --
11197 ---------------------------------------
11198
11199 procedure Resolve_Unchecked_Type_Conversion
11200 (N : Node_Id;
11201 Typ : Entity_Id)
11202 is
11203 pragma Warnings (Off, Typ);
11204
11205 Operand : constant Node_Id := Expression (N);
11206 Opnd_Type : constant Entity_Id := Etype (Operand);
11207
11208 begin
11209 -- Resolve operand using its own type
11210
11211 Resolve (Operand, Opnd_Type);
11212
11213 -- In an inlined context, the unchecked conversion may be applied
11214 -- to a literal, in which case its type is the type of the context.
11215 -- (In other contexts conversions cannot apply to literals).
11216
11217 if In_Inlined_Body
11218 and then (Opnd_Type = Any_Character or else
11219 Opnd_Type = Any_Integer or else
11220 Opnd_Type = Any_Real)
11221 then
11222 Set_Etype (Operand, Typ);
11223 end if;
11224
11225 Analyze_Dimension (N);
11226 Eval_Unchecked_Conversion (N);
11227 end Resolve_Unchecked_Type_Conversion;
11228
11229 ------------------------------
11230 -- Rewrite_Operator_As_Call --
11231 ------------------------------
11232
11233 procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id) is
11234 Loc : constant Source_Ptr := Sloc (N);
11235 Actuals : constant List_Id := New_List;
11236 New_N : Node_Id;
11237
11238 begin
11239 if Nkind (N) in N_Binary_Op then
11240 Append (Left_Opnd (N), Actuals);
11241 end if;
11242
11243 Append (Right_Opnd (N), Actuals);
11244
11245 New_N :=
11246 Make_Function_Call (Sloc => Loc,
11247 Name => New_Occurrence_Of (Nam, Loc),
11248 Parameter_Associations => Actuals);
11249
11250 Preserve_Comes_From_Source (New_N, N);
11251 Preserve_Comes_From_Source (Name (New_N), N);
11252 Rewrite (N, New_N);
11253 Set_Etype (N, Etype (Nam));
11254 end Rewrite_Operator_As_Call;
11255
11256 ------------------------------
11257 -- Rewrite_Renamed_Operator --
11258 ------------------------------
11259
11260 procedure Rewrite_Renamed_Operator
11261 (N : Node_Id;
11262 Op : Entity_Id;
11263 Typ : Entity_Id)
11264 is
11265 Nam : constant Name_Id := Chars (Op);
11266 Is_Binary : constant Boolean := Nkind (N) in N_Binary_Op;
11267 Op_Node : Node_Id;
11268
11269 begin
11270 -- Do not perform this transformation within a pre/postcondition,
11271 -- because the expression will be re-analyzed, and the transformation
11272 -- might affect the visibility of the operator, e.g. in an instance.
11273 -- Note that fully analyzed and expanded pre/postconditions appear as
11274 -- pragma Check equivalents.
11275
11276 if In_Pre_Post_Condition (N) then
11277 return;
11278 end if;
11279
11280 -- Rewrite the operator node using the real operator, not its renaming.
11281 -- Exclude user-defined intrinsic operations of the same name, which are
11282 -- treated separately and rewritten as calls.
11283
11284 if Ekind (Op) /= E_Function or else Chars (N) /= Nam then
11285 Op_Node := New_Node (Operator_Kind (Nam, Is_Binary), Sloc (N));
11286 Set_Chars (Op_Node, Nam);
11287 Set_Etype (Op_Node, Etype (N));
11288 Set_Entity (Op_Node, Op);
11289 Set_Right_Opnd (Op_Node, Right_Opnd (N));
11290
11291 -- Indicate that both the original entity and its renaming are
11292 -- referenced at this point.
11293
11294 Generate_Reference (Entity (N), N);
11295 Generate_Reference (Op, N);
11296
11297 if Is_Binary then
11298 Set_Left_Opnd (Op_Node, Left_Opnd (N));
11299 end if;
11300
11301 Rewrite (N, Op_Node);
11302
11303 -- If the context type is private, add the appropriate conversions so
11304 -- that the operator is applied to the full view. This is done in the
11305 -- routines that resolve intrinsic operators.
11306
11307 if Is_Intrinsic_Subprogram (Op) and then Is_Private_Type (Typ) then
11308 case Nkind (N) is
11309 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
11310 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
11311 Resolve_Intrinsic_Operator (N, Typ);
11312
11313 when N_Op_Plus | N_Op_Minus | N_Op_Abs =>
11314 Resolve_Intrinsic_Unary_Operator (N, Typ);
11315
11316 when others =>
11317 Resolve (N, Typ);
11318 end case;
11319 end if;
11320
11321 elsif Ekind (Op) = E_Function and then Is_Intrinsic_Subprogram (Op) then
11322
11323 -- Operator renames a user-defined operator of the same name. Use the
11324 -- original operator in the node, which is the one Gigi knows about.
11325
11326 Set_Entity (N, Op);
11327 Set_Is_Overloaded (N, False);
11328 end if;
11329 end Rewrite_Renamed_Operator;
11330
11331 -----------------------
11332 -- Set_Slice_Subtype --
11333 -----------------------
11334
11335 -- Build an implicit subtype declaration to represent the type delivered by
11336 -- the slice. This is an abbreviated version of an array subtype. We define
11337 -- an index subtype for the slice, using either the subtype name or the
11338 -- discrete range of the slice. To be consistent with index usage elsewhere
11339 -- we create a list header to hold the single index. This list is not
11340 -- otherwise attached to the syntax tree.
11341
11342 procedure Set_Slice_Subtype (N : Node_Id) is
11343 Loc : constant Source_Ptr := Sloc (N);
11344 Index_List : constant List_Id := New_List;
11345 Index : Node_Id;
11346 Index_Subtype : Entity_Id;
11347 Index_Type : Entity_Id;
11348 Slice_Subtype : Entity_Id;
11349 Drange : constant Node_Id := Discrete_Range (N);
11350
11351 begin
11352 Index_Type := Base_Type (Etype (Drange));
11353
11354 if Is_Entity_Name (Drange) then
11355 Index_Subtype := Entity (Drange);
11356
11357 else
11358 -- We force the evaluation of a range. This is definitely needed in
11359 -- the renamed case, and seems safer to do unconditionally. Note in
11360 -- any case that since we will create and insert an Itype referring
11361 -- to this range, we must make sure any side effect removal actions
11362 -- are inserted before the Itype definition.
11363
11364 if Nkind (Drange) = N_Range then
11365 Force_Evaluation (Low_Bound (Drange));
11366 Force_Evaluation (High_Bound (Drange));
11367
11368 -- If the discrete range is given by a subtype indication, the
11369 -- type of the slice is the base of the subtype mark.
11370
11371 elsif Nkind (Drange) = N_Subtype_Indication then
11372 declare
11373 R : constant Node_Id := Range_Expression (Constraint (Drange));
11374 begin
11375 Index_Type := Base_Type (Entity (Subtype_Mark (Drange)));
11376 Force_Evaluation (Low_Bound (R));
11377 Force_Evaluation (High_Bound (R));
11378 end;
11379 end if;
11380
11381 Index_Subtype := Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
11382
11383 -- Take a new copy of Drange (where bounds have been rewritten to
11384 -- reference side-effect-free names). Using a separate tree ensures
11385 -- that further expansion (e.g. while rewriting a slice assignment
11386 -- into a FOR loop) does not attempt to remove side effects on the
11387 -- bounds again (which would cause the bounds in the index subtype
11388 -- definition to refer to temporaries before they are defined) (the
11389 -- reason is that some names are considered side effect free here
11390 -- for the subtype, but not in the context of a loop iteration
11391 -- scheme).
11392
11393 Set_Scalar_Range (Index_Subtype, New_Copy_Tree (Drange));
11394 Set_Parent (Scalar_Range (Index_Subtype), Index_Subtype);
11395 Set_Etype (Index_Subtype, Index_Type);
11396 Set_Size_Info (Index_Subtype, Index_Type);
11397 Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
11398 end if;
11399
11400 Slice_Subtype := Create_Itype (E_Array_Subtype, N);
11401
11402 Index := New_Occurrence_Of (Index_Subtype, Loc);
11403 Set_Etype (Index, Index_Subtype);
11404 Append (Index, Index_List);
11405
11406 Set_First_Index (Slice_Subtype, Index);
11407 Set_Etype (Slice_Subtype, Base_Type (Etype (N)));
11408 Set_Is_Constrained (Slice_Subtype, True);
11409
11410 Check_Compile_Time_Size (Slice_Subtype);
11411
11412 -- The Etype of the existing Slice node is reset to this slice subtype.
11413 -- Its bounds are obtained from its first index.
11414
11415 Set_Etype (N, Slice_Subtype);
11416
11417 -- For packed slice subtypes, freeze immediately (except in the case of
11418 -- being in a "spec expression" where we never freeze when we first see
11419 -- the expression).
11420
11421 if Is_Packed (Slice_Subtype) and not In_Spec_Expression then
11422 Freeze_Itype (Slice_Subtype, N);
11423
11424 -- For all other cases insert an itype reference in the slice's actions
11425 -- so that the itype is frozen at the proper place in the tree (i.e. at
11426 -- the point where actions for the slice are analyzed). Note that this
11427 -- is different from freezing the itype immediately, which might be
11428 -- premature (e.g. if the slice is within a transient scope). This needs
11429 -- to be done only if expansion is enabled.
11430
11431 elsif Expander_Active then
11432 Ensure_Defined (Typ => Slice_Subtype, N => N);
11433 end if;
11434 end Set_Slice_Subtype;
11435
11436 --------------------------------
11437 -- Set_String_Literal_Subtype --
11438 --------------------------------
11439
11440 procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id) is
11441 Loc : constant Source_Ptr := Sloc (N);
11442 Low_Bound : constant Node_Id :=
11443 Type_Low_Bound (Etype (First_Index (Typ)));
11444 Subtype_Id : Entity_Id;
11445
11446 begin
11447 if Nkind (N) /= N_String_Literal then
11448 return;
11449 end if;
11450
11451 Subtype_Id := Create_Itype (E_String_Literal_Subtype, N);
11452 Set_String_Literal_Length (Subtype_Id, UI_From_Int
11453 (String_Length (Strval (N))));
11454 Set_Etype (Subtype_Id, Base_Type (Typ));
11455 Set_Is_Constrained (Subtype_Id);
11456 Set_Etype (N, Subtype_Id);
11457
11458 -- The low bound is set from the low bound of the corresponding index
11459 -- type. Note that we do not store the high bound in the string literal
11460 -- subtype, but it can be deduced if necessary from the length and the
11461 -- low bound.
11462
11463 if Is_OK_Static_Expression (Low_Bound) then
11464 Set_String_Literal_Low_Bound (Subtype_Id, Low_Bound);
11465
11466 -- If the lower bound is not static we create a range for the string
11467 -- literal, using the index type and the known length of the literal.
11468 -- The index type is not necessarily Positive, so the upper bound is
11469 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11470
11471 else
11472 declare
11473 Index_List : constant List_Id := New_List;
11474 Index_Type : constant Entity_Id := Etype (First_Index (Typ));
11475 High_Bound : constant Node_Id :=
11476 Make_Attribute_Reference (Loc,
11477 Attribute_Name => Name_Val,
11478 Prefix =>
11479 New_Occurrence_Of (Index_Type, Loc),
11480 Expressions => New_List (
11481 Make_Op_Add (Loc,
11482 Left_Opnd =>
11483 Make_Attribute_Reference (Loc,
11484 Attribute_Name => Name_Pos,
11485 Prefix =>
11486 New_Occurrence_Of (Index_Type, Loc),
11487 Expressions =>
11488 New_List (New_Copy_Tree (Low_Bound))),
11489 Right_Opnd =>
11490 Make_Integer_Literal (Loc,
11491 String_Length (Strval (N)) - 1))));
11492
11493 Array_Subtype : Entity_Id;
11494 Drange : Node_Id;
11495 Index : Node_Id;
11496 Index_Subtype : Entity_Id;
11497
11498 begin
11499 if Is_Integer_Type (Index_Type) then
11500 Set_String_Literal_Low_Bound
11501 (Subtype_Id, Make_Integer_Literal (Loc, 1));
11502
11503 else
11504 -- If the index type is an enumeration type, build bounds
11505 -- expression with attributes.
11506
11507 Set_String_Literal_Low_Bound
11508 (Subtype_Id,
11509 Make_Attribute_Reference (Loc,
11510 Attribute_Name => Name_First,
11511 Prefix =>
11512 New_Occurrence_Of (Base_Type (Index_Type), Loc)));
11513 Set_Etype (String_Literal_Low_Bound (Subtype_Id), Index_Type);
11514 end if;
11515
11516 Analyze_And_Resolve (String_Literal_Low_Bound (Subtype_Id));
11517
11518 -- Build bona fide subtype for the string, and wrap it in an
11519 -- unchecked conversion, because the backend expects the
11520 -- String_Literal_Subtype to have a static lower bound.
11521
11522 Index_Subtype :=
11523 Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
11524 Drange := Make_Range (Loc, New_Copy_Tree (Low_Bound), High_Bound);
11525 Set_Scalar_Range (Index_Subtype, Drange);
11526 Set_Parent (Drange, N);
11527 Analyze_And_Resolve (Drange, Index_Type);
11528
11529 -- In the context, the Index_Type may already have a constraint,
11530 -- so use common base type on string subtype. The base type may
11531 -- be used when generating attributes of the string, for example
11532 -- in the context of a slice assignment.
11533
11534 Set_Etype (Index_Subtype, Base_Type (Index_Type));
11535 Set_Size_Info (Index_Subtype, Index_Type);
11536 Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
11537
11538 Array_Subtype := Create_Itype (E_Array_Subtype, N);
11539
11540 Index := New_Occurrence_Of (Index_Subtype, Loc);
11541 Set_Etype (Index, Index_Subtype);
11542 Append (Index, Index_List);
11543
11544 Set_First_Index (Array_Subtype, Index);
11545 Set_Etype (Array_Subtype, Base_Type (Typ));
11546 Set_Is_Constrained (Array_Subtype, True);
11547
11548 Rewrite (N,
11549 Make_Unchecked_Type_Conversion (Loc,
11550 Subtype_Mark => New_Occurrence_Of (Array_Subtype, Loc),
11551 Expression => Relocate_Node (N)));
11552 Set_Etype (N, Array_Subtype);
11553 end;
11554 end if;
11555 end Set_String_Literal_Subtype;
11556
11557 ------------------------------
11558 -- Simplify_Type_Conversion --
11559 ------------------------------
11560
11561 procedure Simplify_Type_Conversion (N : Node_Id) is
11562 begin
11563 if Nkind (N) = N_Type_Conversion then
11564 declare
11565 Operand : constant Node_Id := Expression (N);
11566 Target_Typ : constant Entity_Id := Etype (N);
11567 Opnd_Typ : constant Entity_Id := Etype (Operand);
11568
11569 begin
11570 -- Special processing if the conversion is the expression of a
11571 -- Rounding or Truncation attribute reference. In this case we
11572 -- replace:
11573
11574 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11575
11576 -- by
11577
11578 -- ityp (x)
11579
11580 -- with the Float_Truncate flag set to False or True respectively,
11581 -- which is more efficient.
11582
11583 if Is_Floating_Point_Type (Opnd_Typ)
11584 and then
11585 (Is_Integer_Type (Target_Typ)
11586 or else (Is_Fixed_Point_Type (Target_Typ)
11587 and then Conversion_OK (N)))
11588 and then Nkind (Operand) = N_Attribute_Reference
11589 and then Nam_In (Attribute_Name (Operand), Name_Rounding,
11590 Name_Truncation)
11591 then
11592 declare
11593 Truncate : constant Boolean :=
11594 Attribute_Name (Operand) = Name_Truncation;
11595 begin
11596 Rewrite (Operand,
11597 Relocate_Node (First (Expressions (Operand))));
11598 Set_Float_Truncate (N, Truncate);
11599 end;
11600 end if;
11601 end;
11602 end if;
11603 end Simplify_Type_Conversion;
11604
11605 -----------------------------
11606 -- Unique_Fixed_Point_Type --
11607 -----------------------------
11608
11609 function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id is
11610 T1 : Entity_Id := Empty;
11611 T2 : Entity_Id;
11612 Item : Node_Id;
11613 Scop : Entity_Id;
11614
11615 procedure Fixed_Point_Error;
11616 -- Give error messages for true ambiguity. Messages are posted on node
11617 -- N, and entities T1, T2 are the possible interpretations.
11618
11619 -----------------------
11620 -- Fixed_Point_Error --
11621 -----------------------
11622
11623 procedure Fixed_Point_Error is
11624 begin
11625 Error_Msg_N ("ambiguous universal_fixed_expression", N);
11626 Error_Msg_NE ("\\possible interpretation as}", N, T1);
11627 Error_Msg_NE ("\\possible interpretation as}", N, T2);
11628 end Fixed_Point_Error;
11629
11630 -- Start of processing for Unique_Fixed_Point_Type
11631
11632 begin
11633 -- The operations on Duration are visible, so Duration is always a
11634 -- possible interpretation.
11635
11636 T1 := Standard_Duration;
11637
11638 -- Look for fixed-point types in enclosing scopes
11639
11640 Scop := Current_Scope;
11641 while Scop /= Standard_Standard loop
11642 T2 := First_Entity (Scop);
11643 while Present (T2) loop
11644 if Is_Fixed_Point_Type (T2)
11645 and then Current_Entity (T2) = T2
11646 and then Scope (Base_Type (T2)) = Scop
11647 then
11648 if Present (T1) then
11649 Fixed_Point_Error;
11650 return Any_Type;
11651 else
11652 T1 := T2;
11653 end if;
11654 end if;
11655
11656 Next_Entity (T2);
11657 end loop;
11658
11659 Scop := Scope (Scop);
11660 end loop;
11661
11662 -- Look for visible fixed type declarations in the context
11663
11664 Item := First (Context_Items (Cunit (Current_Sem_Unit)));
11665 while Present (Item) loop
11666 if Nkind (Item) = N_With_Clause then
11667 Scop := Entity (Name (Item));
11668 T2 := First_Entity (Scop);
11669 while Present (T2) loop
11670 if Is_Fixed_Point_Type (T2)
11671 and then Scope (Base_Type (T2)) = Scop
11672 and then (Is_Potentially_Use_Visible (T2) or else In_Use (T2))
11673 then
11674 if Present (T1) then
11675 Fixed_Point_Error;
11676 return Any_Type;
11677 else
11678 T1 := T2;
11679 end if;
11680 end if;
11681
11682 Next_Entity (T2);
11683 end loop;
11684 end if;
11685
11686 Next (Item);
11687 end loop;
11688
11689 if Nkind (N) = N_Real_Literal then
11690 Error_Msg_NE
11691 ("??real literal interpreted as }!", N, T1);
11692 else
11693 Error_Msg_NE
11694 ("??universal_fixed expression interpreted as }!", N, T1);
11695 end if;
11696
11697 return T1;
11698 end Unique_Fixed_Point_Type;
11699
11700 ----------------------
11701 -- Valid_Conversion --
11702 ----------------------
11703
11704 function Valid_Conversion
11705 (N : Node_Id;
11706 Target : Entity_Id;
11707 Operand : Node_Id;
11708 Report_Errs : Boolean := True) return Boolean
11709 is
11710 Target_Type : constant Entity_Id := Base_Type (Target);
11711 Opnd_Type : Entity_Id := Etype (Operand);
11712 Inc_Ancestor : Entity_Id;
11713
11714 function Conversion_Check
11715 (Valid : Boolean;
11716 Msg : String) return Boolean;
11717 -- Little routine to post Msg if Valid is False, returns Valid value
11718
11719 procedure Conversion_Error_N (Msg : String; N : Node_Or_Entity_Id);
11720 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11721
11722 procedure Conversion_Error_NE
11723 (Msg : String;
11724 N : Node_Or_Entity_Id;
11725 E : Node_Or_Entity_Id);
11726 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11727
11728 function Valid_Tagged_Conversion
11729 (Target_Type : Entity_Id;
11730 Opnd_Type : Entity_Id) return Boolean;
11731 -- Specifically test for validity of tagged conversions
11732
11733 function Valid_Array_Conversion return Boolean;
11734 -- Check index and component conformance, and accessibility levels if
11735 -- the component types are anonymous access types (Ada 2005).
11736
11737 ----------------------
11738 -- Conversion_Check --
11739 ----------------------
11740
11741 function Conversion_Check
11742 (Valid : Boolean;
11743 Msg : String) return Boolean
11744 is
11745 begin
11746 if not Valid
11747
11748 -- A generic unit has already been analyzed and we have verified
11749 -- that a particular conversion is OK in that context. Since the
11750 -- instance is reanalyzed without relying on the relationships
11751 -- established during the analysis of the generic, it is possible
11752 -- to end up with inconsistent views of private types. Do not emit
11753 -- the error message in such cases. The rest of the machinery in
11754 -- Valid_Conversion still ensures the proper compatibility of
11755 -- target and operand types.
11756
11757 and then not In_Instance
11758 then
11759 Conversion_Error_N (Msg, Operand);
11760 end if;
11761
11762 return Valid;
11763 end Conversion_Check;
11764
11765 ------------------------
11766 -- Conversion_Error_N --
11767 ------------------------
11768
11769 procedure Conversion_Error_N (Msg : String; N : Node_Or_Entity_Id) is
11770 begin
11771 if Report_Errs then
11772 Error_Msg_N (Msg, N);
11773 end if;
11774 end Conversion_Error_N;
11775
11776 -------------------------
11777 -- Conversion_Error_NE --
11778 -------------------------
11779
11780 procedure Conversion_Error_NE
11781 (Msg : String;
11782 N : Node_Or_Entity_Id;
11783 E : Node_Or_Entity_Id)
11784 is
11785 begin
11786 if Report_Errs then
11787 Error_Msg_NE (Msg, N, E);
11788 end if;
11789 end Conversion_Error_NE;
11790
11791 ----------------------------
11792 -- Valid_Array_Conversion --
11793 ----------------------------
11794
11795 function Valid_Array_Conversion return Boolean
11796 is
11797 Opnd_Comp_Type : constant Entity_Id := Component_Type (Opnd_Type);
11798 Opnd_Comp_Base : constant Entity_Id := Base_Type (Opnd_Comp_Type);
11799
11800 Opnd_Index : Node_Id;
11801 Opnd_Index_Type : Entity_Id;
11802
11803 Target_Comp_Type : constant Entity_Id :=
11804 Component_Type (Target_Type);
11805 Target_Comp_Base : constant Entity_Id :=
11806 Base_Type (Target_Comp_Type);
11807
11808 Target_Index : Node_Id;
11809 Target_Index_Type : Entity_Id;
11810
11811 begin
11812 -- Error if wrong number of dimensions
11813
11814 if
11815 Number_Dimensions (Target_Type) /= Number_Dimensions (Opnd_Type)
11816 then
11817 Conversion_Error_N
11818 ("incompatible number of dimensions for conversion", Operand);
11819 return False;
11820
11821 -- Number of dimensions matches
11822
11823 else
11824 -- Loop through indexes of the two arrays
11825
11826 Target_Index := First_Index (Target_Type);
11827 Opnd_Index := First_Index (Opnd_Type);
11828 while Present (Target_Index) and then Present (Opnd_Index) loop
11829 Target_Index_Type := Etype (Target_Index);
11830 Opnd_Index_Type := Etype (Opnd_Index);
11831
11832 -- Error if index types are incompatible
11833
11834 if not (Is_Integer_Type (Target_Index_Type)
11835 and then Is_Integer_Type (Opnd_Index_Type))
11836 and then (Root_Type (Target_Index_Type)
11837 /= Root_Type (Opnd_Index_Type))
11838 then
11839 Conversion_Error_N
11840 ("incompatible index types for array conversion",
11841 Operand);
11842 return False;
11843 end if;
11844
11845 Next_Index (Target_Index);
11846 Next_Index (Opnd_Index);
11847 end loop;
11848
11849 -- If component types have same base type, all set
11850
11851 if Target_Comp_Base = Opnd_Comp_Base then
11852 null;
11853
11854 -- Here if base types of components are not the same. The only
11855 -- time this is allowed is if we have anonymous access types.
11856
11857 -- The conversion of arrays of anonymous access types can lead
11858 -- to dangling pointers. AI-392 formalizes the accessibility
11859 -- checks that must be applied to such conversions to prevent
11860 -- out-of-scope references.
11861
11862 elsif Ekind_In
11863 (Target_Comp_Base, E_Anonymous_Access_Type,
11864 E_Anonymous_Access_Subprogram_Type)
11865 and then Ekind (Opnd_Comp_Base) = Ekind (Target_Comp_Base)
11866 and then
11867 Subtypes_Statically_Match (Target_Comp_Type, Opnd_Comp_Type)
11868 then
11869 if Type_Access_Level (Target_Type) <
11870 Deepest_Type_Access_Level (Opnd_Type)
11871 then
11872 if In_Instance_Body then
11873 Error_Msg_Warn := SPARK_Mode /= On;
11874 Conversion_Error_N
11875 ("source array type has deeper accessibility "
11876 & "level than target<<", Operand);
11877 Conversion_Error_N ("\Program_Error [<<", Operand);
11878 Rewrite (N,
11879 Make_Raise_Program_Error (Sloc (N),
11880 Reason => PE_Accessibility_Check_Failed));
11881 Set_Etype (N, Target_Type);
11882 return False;
11883
11884 -- Conversion not allowed because of accessibility levels
11885
11886 else
11887 Conversion_Error_N
11888 ("source array type has deeper accessibility "
11889 & "level than target", Operand);
11890 return False;
11891 end if;
11892
11893 else
11894 null;
11895 end if;
11896
11897 -- All other cases where component base types do not match
11898
11899 else
11900 Conversion_Error_N
11901 ("incompatible component types for array conversion",
11902 Operand);
11903 return False;
11904 end if;
11905
11906 -- Check that component subtypes statically match. For numeric
11907 -- types this means that both must be either constrained or
11908 -- unconstrained. For enumeration types the bounds must match.
11909 -- All of this is checked in Subtypes_Statically_Match.
11910
11911 if not Subtypes_Statically_Match
11912 (Target_Comp_Type, Opnd_Comp_Type)
11913 then
11914 Conversion_Error_N
11915 ("component subtypes must statically match", Operand);
11916 return False;
11917 end if;
11918 end if;
11919
11920 return True;
11921 end Valid_Array_Conversion;
11922
11923 -----------------------------
11924 -- Valid_Tagged_Conversion --
11925 -----------------------------
11926
11927 function Valid_Tagged_Conversion
11928 (Target_Type : Entity_Id;
11929 Opnd_Type : Entity_Id) return Boolean
11930 is
11931 begin
11932 -- Upward conversions are allowed (RM 4.6(22))
11933
11934 if Covers (Target_Type, Opnd_Type)
11935 or else Is_Ancestor (Target_Type, Opnd_Type)
11936 then
11937 return True;
11938
11939 -- Downward conversion are allowed if the operand is class-wide
11940 -- (RM 4.6(23)).
11941
11942 elsif Is_Class_Wide_Type (Opnd_Type)
11943 and then Covers (Opnd_Type, Target_Type)
11944 then
11945 return True;
11946
11947 elsif Covers (Opnd_Type, Target_Type)
11948 or else Is_Ancestor (Opnd_Type, Target_Type)
11949 then
11950 return
11951 Conversion_Check (False,
11952 "downward conversion of tagged objects not allowed");
11953
11954 -- Ada 2005 (AI-251): The conversion to/from interface types is
11955 -- always valid. The types involved may be class-wide (sub)types.
11956
11957 elsif Is_Interface (Etype (Base_Type (Target_Type)))
11958 or else Is_Interface (Etype (Base_Type (Opnd_Type)))
11959 then
11960 return True;
11961
11962 -- If the operand is a class-wide type obtained through a limited_
11963 -- with clause, and the context includes the nonlimited view, use
11964 -- it to determine whether the conversion is legal.
11965
11966 elsif Is_Class_Wide_Type (Opnd_Type)
11967 and then From_Limited_With (Opnd_Type)
11968 and then Present (Non_Limited_View (Etype (Opnd_Type)))
11969 and then Is_Interface (Non_Limited_View (Etype (Opnd_Type)))
11970 then
11971 return True;
11972
11973 elsif Is_Access_Type (Opnd_Type)
11974 and then Is_Interface (Directly_Designated_Type (Opnd_Type))
11975 then
11976 return True;
11977
11978 else
11979 Conversion_Error_NE
11980 ("invalid tagged conversion, not compatible with}",
11981 N, First_Subtype (Opnd_Type));
11982 return False;
11983 end if;
11984 end Valid_Tagged_Conversion;
11985
11986 -- Start of processing for Valid_Conversion
11987
11988 begin
11989 Check_Parameterless_Call (Operand);
11990
11991 if Is_Overloaded (Operand) then
11992 declare
11993 I : Interp_Index;
11994 I1 : Interp_Index;
11995 It : Interp;
11996 It1 : Interp;
11997 N1 : Entity_Id;
11998 T1 : Entity_Id;
11999
12000 begin
12001 -- Remove procedure calls, which syntactically cannot appear in
12002 -- this context, but which cannot be removed by type checking,
12003 -- because the context does not impose a type.
12004
12005 -- The node may be labelled overloaded, but still contain only one
12006 -- interpretation because others were discarded earlier. If this
12007 -- is the case, retain the single interpretation if legal.
12008
12009 Get_First_Interp (Operand, I, It);
12010 Opnd_Type := It.Typ;
12011 Get_Next_Interp (I, It);
12012
12013 if Present (It.Typ)
12014 and then Opnd_Type /= Standard_Void_Type
12015 then
12016 -- More than one candidate interpretation is available
12017
12018 Get_First_Interp (Operand, I, It);
12019 while Present (It.Typ) loop
12020 if It.Typ = Standard_Void_Type then
12021 Remove_Interp (I);
12022 end if;
12023
12024 -- When compiling for a system where Address is of a visible
12025 -- integer type, spurious ambiguities can be produced when
12026 -- arithmetic operations have a literal operand and return
12027 -- System.Address or a descendant of it. These ambiguities
12028 -- are usually resolved by the context, but for conversions
12029 -- there is no context type and the removal of the spurious
12030 -- operations must be done explicitly here.
12031
12032 if not Address_Is_Private
12033 and then Is_Descendant_Of_Address (It.Typ)
12034 then
12035 Remove_Interp (I);
12036 end if;
12037
12038 Get_Next_Interp (I, It);
12039 end loop;
12040 end if;
12041
12042 Get_First_Interp (Operand, I, It);
12043 I1 := I;
12044 It1 := It;
12045
12046 if No (It.Typ) then
12047 Conversion_Error_N ("illegal operand in conversion", Operand);
12048 return False;
12049 end if;
12050
12051 Get_Next_Interp (I, It);
12052
12053 if Present (It.Typ) then
12054 N1 := It1.Nam;
12055 T1 := It1.Typ;
12056 It1 := Disambiguate (Operand, I1, I, Any_Type);
12057
12058 if It1 = No_Interp then
12059 Conversion_Error_N
12060 ("ambiguous operand in conversion", Operand);
12061
12062 -- If the interpretation involves a standard operator, use
12063 -- the location of the type, which may be user-defined.
12064
12065 if Sloc (It.Nam) = Standard_Location then
12066 Error_Msg_Sloc := Sloc (It.Typ);
12067 else
12068 Error_Msg_Sloc := Sloc (It.Nam);
12069 end if;
12070
12071 Conversion_Error_N -- CODEFIX
12072 ("\\possible interpretation#!", Operand);
12073
12074 if Sloc (N1) = Standard_Location then
12075 Error_Msg_Sloc := Sloc (T1);
12076 else
12077 Error_Msg_Sloc := Sloc (N1);
12078 end if;
12079
12080 Conversion_Error_N -- CODEFIX
12081 ("\\possible interpretation#!", Operand);
12082
12083 return False;
12084 end if;
12085 end if;
12086
12087 Set_Etype (Operand, It1.Typ);
12088 Opnd_Type := It1.Typ;
12089 end;
12090 end if;
12091
12092 -- Deal with conversion of integer type to address if the pragma
12093 -- Allow_Integer_Address is in effect. We convert the conversion to
12094 -- an unchecked conversion in this case and we are all done.
12095
12096 if Address_Integer_Convert_OK (Opnd_Type, Target_Type) then
12097 Rewrite (N, Unchecked_Convert_To (Target_Type, Expression (N)));
12098 Analyze_And_Resolve (N, Target_Type);
12099 return True;
12100 end if;
12101
12102 -- If we are within a child unit, check whether the type of the
12103 -- expression has an ancestor in a parent unit, in which case it
12104 -- belongs to its derivation class even if the ancestor is private.
12105 -- See RM 7.3.1 (5.2/3).
12106
12107 Inc_Ancestor := Get_Incomplete_View_Of_Ancestor (Opnd_Type);
12108
12109 -- Numeric types
12110
12111 if Is_Numeric_Type (Target_Type) then
12112
12113 -- A universal fixed expression can be converted to any numeric type
12114
12115 if Opnd_Type = Universal_Fixed then
12116 return True;
12117
12118 -- Also no need to check when in an instance or inlined body, because
12119 -- the legality has been established when the template was analyzed.
12120 -- Furthermore, numeric conversions may occur where only a private
12121 -- view of the operand type is visible at the instantiation point.
12122 -- This results in a spurious error if we check that the operand type
12123 -- is a numeric type.
12124
12125 -- Note: in a previous version of this unit, the following tests were
12126 -- applied only for generated code (Comes_From_Source set to False),
12127 -- but in fact the test is required for source code as well, since
12128 -- this situation can arise in source code.
12129
12130 elsif In_Instance or else In_Inlined_Body then
12131 return True;
12132
12133 -- Otherwise we need the conversion check
12134
12135 else
12136 return Conversion_Check
12137 (Is_Numeric_Type (Opnd_Type)
12138 or else
12139 (Present (Inc_Ancestor)
12140 and then Is_Numeric_Type (Inc_Ancestor)),
12141 "illegal operand for numeric conversion");
12142 end if;
12143
12144 -- Array types
12145
12146 elsif Is_Array_Type (Target_Type) then
12147 if not Is_Array_Type (Opnd_Type)
12148 or else Opnd_Type = Any_Composite
12149 or else Opnd_Type = Any_String
12150 then
12151 Conversion_Error_N
12152 ("illegal operand for array conversion", Operand);
12153 return False;
12154
12155 else
12156 return Valid_Array_Conversion;
12157 end if;
12158
12159 -- Ada 2005 (AI-251): Internally generated conversions of access to
12160 -- interface types added to force the displacement of the pointer to
12161 -- reference the corresponding dispatch table.
12162
12163 elsif not Comes_From_Source (N)
12164 and then Is_Access_Type (Target_Type)
12165 and then Is_Interface (Designated_Type (Target_Type))
12166 then
12167 return True;
12168
12169 -- Ada 2005 (AI-251): Anonymous access types where target references an
12170 -- interface type.
12171
12172 elsif Is_Access_Type (Opnd_Type)
12173 and then Ekind_In (Target_Type, E_General_Access_Type,
12174 E_Anonymous_Access_Type)
12175 and then Is_Interface (Directly_Designated_Type (Target_Type))
12176 then
12177 -- Check the static accessibility rule of 4.6(17). Note that the
12178 -- check is not enforced when within an instance body, since the
12179 -- RM requires such cases to be caught at run time.
12180
12181 -- If the operand is a rewriting of an allocator no check is needed
12182 -- because there are no accessibility issues.
12183
12184 if Nkind (Original_Node (N)) = N_Allocator then
12185 null;
12186
12187 elsif Ekind (Target_Type) /= E_Anonymous_Access_Type then
12188 if Type_Access_Level (Opnd_Type) >
12189 Deepest_Type_Access_Level (Target_Type)
12190 then
12191 -- In an instance, this is a run-time check, but one we know
12192 -- will fail, so generate an appropriate warning. The raise
12193 -- will be generated by Expand_N_Type_Conversion.
12194
12195 if In_Instance_Body then
12196 Error_Msg_Warn := SPARK_Mode /= On;
12197 Conversion_Error_N
12198 ("cannot convert local pointer to non-local access type<<",
12199 Operand);
12200 Conversion_Error_N ("\Program_Error [<<", Operand);
12201
12202 else
12203 Conversion_Error_N
12204 ("cannot convert local pointer to non-local access type",
12205 Operand);
12206 return False;
12207 end if;
12208
12209 -- Special accessibility checks are needed in the case of access
12210 -- discriminants declared for a limited type.
12211
12212 elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type
12213 and then not Is_Local_Anonymous_Access (Opnd_Type)
12214 then
12215 -- When the operand is a selected access discriminant the check
12216 -- needs to be made against the level of the object denoted by
12217 -- the prefix of the selected name (Object_Access_Level handles
12218 -- checking the prefix of the operand for this case).
12219
12220 if Nkind (Operand) = N_Selected_Component
12221 and then Object_Access_Level (Operand) >
12222 Deepest_Type_Access_Level (Target_Type)
12223 then
12224 -- In an instance, this is a run-time check, but one we know
12225 -- will fail, so generate an appropriate warning. The raise
12226 -- will be generated by Expand_N_Type_Conversion.
12227
12228 if In_Instance_Body then
12229 Error_Msg_Warn := SPARK_Mode /= On;
12230 Conversion_Error_N
12231 ("cannot convert access discriminant to non-local "
12232 & "access type<<", Operand);
12233 Conversion_Error_N ("\Program_Error [<<", Operand);
12234
12235 -- Real error if not in instance body
12236
12237 else
12238 Conversion_Error_N
12239 ("cannot convert access discriminant to non-local "
12240 & "access type", Operand);
12241 return False;
12242 end if;
12243 end if;
12244
12245 -- The case of a reference to an access discriminant from
12246 -- within a limited type declaration (which will appear as
12247 -- a discriminal) is always illegal because the level of the
12248 -- discriminant is considered to be deeper than any (nameable)
12249 -- access type.
12250
12251 if Is_Entity_Name (Operand)
12252 and then not Is_Local_Anonymous_Access (Opnd_Type)
12253 and then
12254 Ekind_In (Entity (Operand), E_In_Parameter, E_Constant)
12255 and then Present (Discriminal_Link (Entity (Operand)))
12256 then
12257 Conversion_Error_N
12258 ("discriminant has deeper accessibility level than target",
12259 Operand);
12260 return False;
12261 end if;
12262 end if;
12263 end if;
12264
12265 return True;
12266
12267 -- General and anonymous access types
12268
12269 elsif Ekind_In (Target_Type, E_General_Access_Type,
12270 E_Anonymous_Access_Type)
12271 and then
12272 Conversion_Check
12273 (Is_Access_Type (Opnd_Type)
12274 and then not
12275 Ekind_In (Opnd_Type, E_Access_Subprogram_Type,
12276 E_Access_Protected_Subprogram_Type),
12277 "must be an access-to-object type")
12278 then
12279 if Is_Access_Constant (Opnd_Type)
12280 and then not Is_Access_Constant (Target_Type)
12281 then
12282 Conversion_Error_N
12283 ("access-to-constant operand type not allowed", Operand);
12284 return False;
12285 end if;
12286
12287 -- Check the static accessibility rule of 4.6(17). Note that the
12288 -- check is not enforced when within an instance body, since the RM
12289 -- requires such cases to be caught at run time.
12290
12291 if Ekind (Target_Type) /= E_Anonymous_Access_Type
12292 or else Is_Local_Anonymous_Access (Target_Type)
12293 or else Nkind (Associated_Node_For_Itype (Target_Type)) =
12294 N_Object_Declaration
12295 then
12296 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12297 -- conversions from an anonymous access type to a named general
12298 -- access type. Such conversions are not allowed in the case of
12299 -- access parameters and stand-alone objects of an anonymous
12300 -- access type. The implicit conversion case is recognized by
12301 -- testing that Comes_From_Source is False and that it's been
12302 -- rewritten. The Comes_From_Source test isn't sufficient because
12303 -- nodes in inlined calls to predefined library routines can have
12304 -- Comes_From_Source set to False. (Is there a better way to test
12305 -- for implicit conversions???)
12306
12307 if Ada_Version >= Ada_2012
12308 and then not Comes_From_Source (N)
12309 and then N /= Original_Node (N)
12310 and then Ekind (Target_Type) = E_General_Access_Type
12311 and then Ekind (Opnd_Type) = E_Anonymous_Access_Type
12312 then
12313 if Is_Itype (Opnd_Type) then
12314
12315 -- Implicit conversions aren't allowed for objects of an
12316 -- anonymous access type, since such objects have nonstatic
12317 -- levels in Ada 2012.
12318
12319 if Nkind (Associated_Node_For_Itype (Opnd_Type)) =
12320 N_Object_Declaration
12321 then
12322 Conversion_Error_N
12323 ("implicit conversion of stand-alone anonymous "
12324 & "access object not allowed", Operand);
12325 return False;
12326
12327 -- Implicit conversions aren't allowed for anonymous access
12328 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12329 -- is done to exclude anonymous access results.
12330
12331 elsif not Is_Local_Anonymous_Access (Opnd_Type)
12332 and then Nkind_In (Associated_Node_For_Itype (Opnd_Type),
12333 N_Function_Specification,
12334 N_Procedure_Specification)
12335 then
12336 Conversion_Error_N
12337 ("implicit conversion of anonymous access formal "
12338 & "not allowed", Operand);
12339 return False;
12340
12341 -- This is a case where there's an enclosing object whose
12342 -- to which the "statically deeper than" relationship does
12343 -- not apply (such as an access discriminant selected from
12344 -- a dereference of an access parameter).
12345
12346 elsif Object_Access_Level (Operand)
12347 = Scope_Depth (Standard_Standard)
12348 then
12349 Conversion_Error_N
12350 ("implicit conversion of anonymous access value "
12351 & "not allowed", Operand);
12352 return False;
12353
12354 -- In other cases, the level of the operand's type must be
12355 -- statically less deep than that of the target type, else
12356 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12357
12358 elsif Type_Access_Level (Opnd_Type) >
12359 Deepest_Type_Access_Level (Target_Type)
12360 then
12361 Conversion_Error_N
12362 ("implicit conversion of anonymous access value "
12363 & "violates accessibility", Operand);
12364 return False;
12365 end if;
12366 end if;
12367
12368 elsif Type_Access_Level (Opnd_Type) >
12369 Deepest_Type_Access_Level (Target_Type)
12370 then
12371 -- In an instance, this is a run-time check, but one we know
12372 -- will fail, so generate an appropriate warning. The raise
12373 -- will be generated by Expand_N_Type_Conversion.
12374
12375 if In_Instance_Body then
12376 Error_Msg_Warn := SPARK_Mode /= On;
12377 Conversion_Error_N
12378 ("cannot convert local pointer to non-local access type<<",
12379 Operand);
12380 Conversion_Error_N ("\Program_Error [<<", Operand);
12381
12382 -- If not in an instance body, this is a real error
12383
12384 else
12385 -- Avoid generation of spurious error message
12386
12387 if not Error_Posted (N) then
12388 Conversion_Error_N
12389 ("cannot convert local pointer to non-local access type",
12390 Operand);
12391 end if;
12392
12393 return False;
12394 end if;
12395
12396 -- Special accessibility checks are needed in the case of access
12397 -- discriminants declared for a limited type.
12398
12399 elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type
12400 and then not Is_Local_Anonymous_Access (Opnd_Type)
12401 then
12402 -- When the operand is a selected access discriminant the check
12403 -- needs to be made against the level of the object denoted by
12404 -- the prefix of the selected name (Object_Access_Level handles
12405 -- checking the prefix of the operand for this case).
12406
12407 if Nkind (Operand) = N_Selected_Component
12408 and then Object_Access_Level (Operand) >
12409 Deepest_Type_Access_Level (Target_Type)
12410 then
12411 -- In an instance, this is a run-time check, but one we know
12412 -- will fail, so generate an appropriate warning. The raise
12413 -- will be generated by Expand_N_Type_Conversion.
12414
12415 if In_Instance_Body then
12416 Error_Msg_Warn := SPARK_Mode /= On;
12417 Conversion_Error_N
12418 ("cannot convert access discriminant to non-local "
12419 & "access type<<", Operand);
12420 Conversion_Error_N ("\Program_Error [<<", Operand);
12421
12422 -- If not in an instance body, this is a real error
12423
12424 else
12425 Conversion_Error_N
12426 ("cannot convert access discriminant to non-local "
12427 & "access type", Operand);
12428 return False;
12429 end if;
12430 end if;
12431
12432 -- The case of a reference to an access discriminant from
12433 -- within a limited type declaration (which will appear as
12434 -- a discriminal) is always illegal because the level of the
12435 -- discriminant is considered to be deeper than any (nameable)
12436 -- access type.
12437
12438 if Is_Entity_Name (Operand)
12439 and then
12440 Ekind_In (Entity (Operand), E_In_Parameter, E_Constant)
12441 and then Present (Discriminal_Link (Entity (Operand)))
12442 then
12443 Conversion_Error_N
12444 ("discriminant has deeper accessibility level than target",
12445 Operand);
12446 return False;
12447 end if;
12448 end if;
12449 end if;
12450
12451 -- In the presence of limited_with clauses we have to use nonlimited
12452 -- views, if available.
12453
12454 Check_Limited : declare
12455 function Full_Designated_Type (T : Entity_Id) return Entity_Id;
12456 -- Helper function to handle limited views
12457
12458 --------------------------
12459 -- Full_Designated_Type --
12460 --------------------------
12461
12462 function Full_Designated_Type (T : Entity_Id) return Entity_Id is
12463 Desig : constant Entity_Id := Designated_Type (T);
12464
12465 begin
12466 -- Handle the limited view of a type
12467
12468 if From_Limited_With (Desig)
12469 and then Has_Non_Limited_View (Desig)
12470 then
12471 return Available_View (Desig);
12472 else
12473 return Desig;
12474 end if;
12475 end Full_Designated_Type;
12476
12477 -- Local Declarations
12478
12479 Target : constant Entity_Id := Full_Designated_Type (Target_Type);
12480 Opnd : constant Entity_Id := Full_Designated_Type (Opnd_Type);
12481
12482 Same_Base : constant Boolean :=
12483 Base_Type (Target) = Base_Type (Opnd);
12484
12485 -- Start of processing for Check_Limited
12486
12487 begin
12488 if Is_Tagged_Type (Target) then
12489 return Valid_Tagged_Conversion (Target, Opnd);
12490
12491 else
12492 if not Same_Base then
12493 Conversion_Error_NE
12494 ("target designated type not compatible with }",
12495 N, Base_Type (Opnd));
12496 return False;
12497
12498 -- Ada 2005 AI-384: legality rule is symmetric in both
12499 -- designated types. The conversion is legal (with possible
12500 -- constraint check) if either designated type is
12501 -- unconstrained.
12502
12503 elsif Subtypes_Statically_Match (Target, Opnd)
12504 or else
12505 (Has_Discriminants (Target)
12506 and then
12507 (not Is_Constrained (Opnd)
12508 or else not Is_Constrained (Target)))
12509 then
12510 -- Special case, if Value_Size has been used to make the
12511 -- sizes different, the conversion is not allowed even
12512 -- though the subtypes statically match.
12513
12514 if Known_Static_RM_Size (Target)
12515 and then Known_Static_RM_Size (Opnd)
12516 and then RM_Size (Target) /= RM_Size (Opnd)
12517 then
12518 Conversion_Error_NE
12519 ("target designated subtype not compatible with }",
12520 N, Opnd);
12521 Conversion_Error_NE
12522 ("\because sizes of the two designated subtypes differ",
12523 N, Opnd);
12524 return False;
12525
12526 -- Normal case where conversion is allowed
12527
12528 else
12529 return True;
12530 end if;
12531
12532 else
12533 Error_Msg_NE
12534 ("target designated subtype not compatible with }",
12535 N, Opnd);
12536 return False;
12537 end if;
12538 end if;
12539 end Check_Limited;
12540
12541 -- Access to subprogram types. If the operand is an access parameter,
12542 -- the type has a deeper accessibility that any master, and cannot be
12543 -- assigned. We must make an exception if the conversion is part of an
12544 -- assignment and the target is the return object of an extended return
12545 -- statement, because in that case the accessibility check takes place
12546 -- after the return.
12547
12548 elsif Is_Access_Subprogram_Type (Target_Type)
12549
12550 -- Note: this test of Opnd_Type is there to prevent entering this
12551 -- branch in the case of a remote access to subprogram type, which
12552 -- is internally represented as an E_Record_Type.
12553
12554 and then Is_Access_Type (Opnd_Type)
12555 then
12556 if Ekind (Base_Type (Opnd_Type)) = E_Anonymous_Access_Subprogram_Type
12557 and then Is_Entity_Name (Operand)
12558 and then Ekind (Entity (Operand)) = E_In_Parameter
12559 and then
12560 (Nkind (Parent (N)) /= N_Assignment_Statement
12561 or else not Is_Entity_Name (Name (Parent (N)))
12562 or else not Is_Return_Object (Entity (Name (Parent (N)))))
12563 then
12564 Conversion_Error_N
12565 ("illegal attempt to store anonymous access to subprogram",
12566 Operand);
12567 Conversion_Error_N
12568 ("\value has deeper accessibility than any master "
12569 & "(RM 3.10.2 (13))",
12570 Operand);
12571
12572 Error_Msg_NE
12573 ("\use named access type for& instead of access parameter",
12574 Operand, Entity (Operand));
12575 end if;
12576
12577 -- Check that the designated types are subtype conformant
12578
12579 Check_Subtype_Conformant (New_Id => Designated_Type (Target_Type),
12580 Old_Id => Designated_Type (Opnd_Type),
12581 Err_Loc => N);
12582
12583 -- Check the static accessibility rule of 4.6(20)
12584
12585 if Type_Access_Level (Opnd_Type) >
12586 Deepest_Type_Access_Level (Target_Type)
12587 then
12588 Conversion_Error_N
12589 ("operand type has deeper accessibility level than target",
12590 Operand);
12591
12592 -- Check that if the operand type is declared in a generic body,
12593 -- then the target type must be declared within that same body
12594 -- (enforces last sentence of 4.6(20)).
12595
12596 elsif Present (Enclosing_Generic_Body (Opnd_Type)) then
12597 declare
12598 O_Gen : constant Node_Id :=
12599 Enclosing_Generic_Body (Opnd_Type);
12600
12601 T_Gen : Node_Id;
12602
12603 begin
12604 T_Gen := Enclosing_Generic_Body (Target_Type);
12605 while Present (T_Gen) and then T_Gen /= O_Gen loop
12606 T_Gen := Enclosing_Generic_Body (T_Gen);
12607 end loop;
12608
12609 if T_Gen /= O_Gen then
12610 Conversion_Error_N
12611 ("target type must be declared in same generic body "
12612 & "as operand type", N);
12613 end if;
12614 end;
12615 end if;
12616
12617 return True;
12618
12619 -- Remote access to subprogram types
12620
12621 elsif Is_Remote_Access_To_Subprogram_Type (Target_Type)
12622 and then Is_Remote_Access_To_Subprogram_Type (Opnd_Type)
12623 then
12624 -- It is valid to convert from one RAS type to another provided
12625 -- that their specification statically match.
12626
12627 -- Note: at this point, remote access to subprogram types have been
12628 -- expanded to their E_Record_Type representation, and we need to
12629 -- go back to the original access type definition using the
12630 -- Corresponding_Remote_Type attribute in order to check that the
12631 -- designated profiles match.
12632
12633 pragma Assert (Ekind (Target_Type) = E_Record_Type);
12634 pragma Assert (Ekind (Opnd_Type) = E_Record_Type);
12635
12636 Check_Subtype_Conformant
12637 (New_Id =>
12638 Designated_Type (Corresponding_Remote_Type (Target_Type)),
12639 Old_Id =>
12640 Designated_Type (Corresponding_Remote_Type (Opnd_Type)),
12641 Err_Loc =>
12642 N);
12643 return True;
12644
12645 -- If it was legal in the generic, it's legal in the instance
12646
12647 elsif In_Instance_Body then
12648 return True;
12649
12650 -- If both are tagged types, check legality of view conversions
12651
12652 elsif Is_Tagged_Type (Target_Type)
12653 and then
12654 Is_Tagged_Type (Opnd_Type)
12655 then
12656 return Valid_Tagged_Conversion (Target_Type, Opnd_Type);
12657
12658 -- Types derived from the same root type are convertible
12659
12660 elsif Root_Type (Target_Type) = Root_Type (Opnd_Type) then
12661 return True;
12662
12663 -- In an instance or an inlined body, there may be inconsistent views of
12664 -- the same type, or of types derived from a common root.
12665
12666 elsif (In_Instance or In_Inlined_Body)
12667 and then
12668 Root_Type (Underlying_Type (Target_Type)) =
12669 Root_Type (Underlying_Type (Opnd_Type))
12670 then
12671 return True;
12672
12673 -- Special check for common access type error case
12674
12675 elsif Ekind (Target_Type) = E_Access_Type
12676 and then Is_Access_Type (Opnd_Type)
12677 then
12678 Conversion_Error_N ("target type must be general access type!", N);
12679 Conversion_Error_NE -- CODEFIX
12680 ("add ALL to }!", N, Target_Type);
12681 return False;
12682
12683 -- Here we have a real conversion error
12684
12685 else
12686 Conversion_Error_NE
12687 ("invalid conversion, not compatible with }", N, Opnd_Type);
12688 return False;
12689 end if;
12690 end Valid_Conversion;
12691
12692 end Sem_Res;