1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree
; use Atree
;
28 with Debug
; use Debug
;
29 with Einfo
; use Einfo
;
30 with Elists
; use Elists
;
31 with Nlists
; use Nlists
;
32 with Errout
; use Errout
;
34 with Namet
; use Namet
;
36 with Output
; use Output
;
38 with Sem_Ch6
; use Sem_Ch6
;
39 with Sem_Ch8
; use Sem_Ch8
;
40 with Sem_Ch12
; use Sem_Ch12
;
41 with Sem_Disp
; use Sem_Disp
;
42 with Sem_Util
; use Sem_Util
;
43 with Stand
; use Stand
;
44 with Sinfo
; use Sinfo
;
45 with Snames
; use Snames
;
47 with Uintp
; use Uintp
;
49 package body Sem_Type
is
55 -- The following data structures establish a mapping between nodes and
56 -- their interpretations. An overloaded node has an entry in Interp_Map,
57 -- which in turn contains a pointer into the All_Interp array. The
58 -- interpretations of a given node are contiguous in All_Interp. Each
59 -- set of interpretations is terminated with the marker No_Interp.
60 -- In order to speed up the retrieval of the interpretations of an
61 -- overloaded node, the Interp_Map table is accessed by means of a simple
62 -- hashing scheme, and the entries in Interp_Map are chained. The heads
63 -- of clash lists are stored in array Headers.
65 -- Headers Interp_Map All_Interp
67 -- _ +-----+ +--------+
68 -- |_| |_____| --->|interp1 |
69 -- |_|---------->|node | | |interp2 |
70 -- |_| |index|---------| |nointerp|
75 -- This scheme does not currently reclaim interpretations. In principle,
76 -- after a unit is compiled, all overloadings have been resolved, and the
77 -- candidate interpretations should be deleted. This should be easier
78 -- now than with the previous scheme???
80 package All_Interp
is new Table
.Table
(
81 Table_Component_Type
=> Interp
,
82 Table_Index_Type
=> Int
,
84 Table_Initial
=> Alloc
.All_Interp_Initial
,
85 Table_Increment
=> Alloc
.All_Interp_Increment
,
86 Table_Name
=> "All_Interp");
88 type Interp_Ref
is record
94 Header_Size
: constant Int
:= 2 ** 12;
95 No_Entry
: constant Int
:= -1;
96 Headers
: array (0 .. Header_Size
) of Int
:= (others => No_Entry
);
98 package Interp_Map
is new Table
.Table
(
99 Table_Component_Type
=> Interp_Ref
,
100 Table_Index_Type
=> Int
,
101 Table_Low_Bound
=> 0,
102 Table_Initial
=> Alloc
.Interp_Map_Initial
,
103 Table_Increment
=> Alloc
.Interp_Map_Increment
,
104 Table_Name
=> "Interp_Map");
106 function Hash
(N
: Node_Id
) return Int
;
107 -- A trivial hashing function for nodes, used to insert an overloaded
108 -- node into the Interp_Map table.
110 -------------------------------------
111 -- Handling of Overload Resolution --
112 -------------------------------------
114 -- Overload resolution uses two passes over the syntax tree of a complete
115 -- context. In the first, bottom-up pass, the types of actuals in calls
116 -- are used to resolve possibly overloaded subprogram and operator names.
117 -- In the second top-down pass, the type of the context (for example the
118 -- condition in a while statement) is used to resolve a possibly ambiguous
119 -- call, and the unique subprogram name in turn imposes a specific context
120 -- on each of its actuals.
122 -- Most expressions are in fact unambiguous, and the bottom-up pass is
123 -- sufficient to resolve most everything. To simplify the common case,
124 -- names and expressions carry a flag Is_Overloaded to indicate whether
125 -- they have more than one interpretation. If the flag is off, then each
126 -- name has already a unique meaning and type, and the bottom-up pass is
127 -- sufficient (and much simpler).
129 --------------------------
130 -- Operator Overloading --
131 --------------------------
133 -- The visibility of operators is handled differently from that of
134 -- other entities. We do not introduce explicit versions of primitive
135 -- operators for each type definition. As a result, there is only one
136 -- entity corresponding to predefined addition on all numeric types, etc.
137 -- The back-end resolves predefined operators according to their type.
138 -- The visibility of primitive operations then reduces to the visibility
139 -- of the resulting type: (a + b) is a legal interpretation of some
140 -- primitive operator + if the type of the result (which must also be
141 -- the type of a and b) is directly visible (i.e. either immediately
142 -- visible or use-visible.)
144 -- User-defined operators are treated like other functions, but the
145 -- visibility of these user-defined operations must be special-cased
146 -- to determine whether they hide or are hidden by predefined operators.
147 -- The form P."+" (x, y) requires additional handling.
149 -- Concatenation is treated more conventionally: for every one-dimensional
150 -- array type we introduce a explicit concatenation operator. This is
151 -- necessary to handle the case of (element & element => array) which
152 -- cannot be handled conveniently if there is no explicit instance of
153 -- resulting type of the operation.
155 -----------------------
156 -- Local Subprograms --
157 -----------------------
159 procedure All_Overloads
;
160 pragma Warnings
(Off
, All_Overloads
);
161 -- Debugging procedure: list full contents of Overloads table
163 function Binary_Op_Interp_Has_Abstract_Op
165 E
: Entity_Id
) return Entity_Id
;
166 -- Given the node and entity of a binary operator, determine whether the
167 -- actuals of E contain an abstract interpretation with regards to the
168 -- types of their corresponding formals. Return the abstract operation or
171 function Function_Interp_Has_Abstract_Op
173 E
: Entity_Id
) return Entity_Id
;
174 -- Given the node and entity of a function call, determine whether the
175 -- actuals of E contain an abstract interpretation with regards to the
176 -- types of their corresponding formals. Return the abstract operation or
179 function Has_Abstract_Op
181 Typ
: Entity_Id
) return Entity_Id
;
182 -- Subsidiary routine to Binary_Op_Interp_Has_Abstract_Op and Function_
183 -- Interp_Has_Abstract_Op. Determine whether an overloaded node has an
184 -- abstract interpretation which yields type Typ.
186 procedure New_Interps
(N
: Node_Id
);
187 -- Initialize collection of interpretations for the given node, which is
188 -- either an overloaded entity, or an operation whose arguments have
189 -- multiple interpretations. Interpretations can be added to only one
192 function Specific_Type
(Typ_1
, Typ_2
: Entity_Id
) return Entity_Id
;
193 -- If Typ_1 and Typ_2 are compatible, return the one that is not universal
194 -- or is not a "class" type (any_character, etc).
200 procedure Add_One_Interp
204 Opnd_Type
: Entity_Id
:= Empty
)
206 Vis_Type
: Entity_Id
;
208 procedure Add_Entry
(Name
: Entity_Id
; Typ
: Entity_Id
);
209 -- Add one interpretation to an overloaded node. Add a new entry if
210 -- not hidden by previous one, and remove previous one if hidden by
213 function Is_Universal_Operation
(Op
: Entity_Id
) return Boolean;
214 -- True if the entity is a predefined operator and the operands have
215 -- a universal Interpretation.
221 procedure Add_Entry
(Name
: Entity_Id
; Typ
: Entity_Id
) is
222 Abstr_Op
: Entity_Id
:= Empty
;
226 -- Start of processing for Add_Entry
229 -- Find out whether the new entry references interpretations that
230 -- are abstract or disabled by abstract operators.
232 if Ada_Version
>= Ada_05
then
233 if Nkind
(N
) in N_Binary_Op
then
234 Abstr_Op
:= Binary_Op_Interp_Has_Abstract_Op
(N
, Name
);
235 elsif Nkind
(N
) = N_Function_Call
then
236 Abstr_Op
:= Function_Interp_Has_Abstract_Op
(N
, Name
);
240 Get_First_Interp
(N
, I
, It
);
241 while Present
(It
.Nam
) loop
243 -- A user-defined subprogram hides another declared at an outer
244 -- level, or one that is use-visible. So return if previous
245 -- definition hides new one (which is either in an outer
246 -- scope, or use-visible). Note that for functions use-visible
247 -- is the same as potentially use-visible. If new one hides
248 -- previous one, replace entry in table of interpretations.
249 -- If this is a universal operation, retain the operator in case
250 -- preference rule applies.
252 if (((Ekind
(Name
) = E_Function
or else Ekind
(Name
) = E_Procedure
)
253 and then Ekind
(Name
) = Ekind
(It
.Nam
))
254 or else (Ekind
(Name
) = E_Operator
255 and then Ekind
(It
.Nam
) = E_Function
))
257 and then Is_Immediately_Visible
(It
.Nam
)
258 and then Type_Conformant
(Name
, It
.Nam
)
259 and then Base_Type
(It
.Typ
) = Base_Type
(T
)
261 if Is_Universal_Operation
(Name
) then
264 -- If node is an operator symbol, we have no actuals with
265 -- which to check hiding, and this is done in full in the
266 -- caller (Analyze_Subprogram_Renaming) so we include the
267 -- predefined operator in any case.
269 elsif Nkind
(N
) = N_Operator_Symbol
270 or else (Nkind
(N
) = N_Expanded_Name
272 Nkind
(Selector_Name
(N
)) = N_Operator_Symbol
)
276 elsif not In_Open_Scopes
(Scope
(Name
))
277 or else Scope_Depth
(Scope
(Name
)) <=
278 Scope_Depth
(Scope
(It
.Nam
))
280 -- If ambiguity within instance, and entity is not an
281 -- implicit operation, save for later disambiguation.
283 if Scope
(Name
) = Scope
(It
.Nam
)
284 and then not Is_Inherited_Operation
(Name
)
293 All_Interp
.Table
(I
).Nam
:= Name
;
297 -- Avoid making duplicate entries in overloads
300 and then Base_Type
(It
.Typ
) = Base_Type
(T
)
304 -- Otherwise keep going
307 Get_Next_Interp
(I
, It
);
312 All_Interp
.Table
(All_Interp
.Last
) := (Name
, Typ
, Abstr_Op
);
313 All_Interp
.Increment_Last
;
314 All_Interp
.Table
(All_Interp
.Last
) := No_Interp
;
317 ----------------------------
318 -- Is_Universal_Operation --
319 ----------------------------
321 function Is_Universal_Operation
(Op
: Entity_Id
) return Boolean is
325 if Ekind
(Op
) /= E_Operator
then
328 elsif Nkind
(N
) in N_Binary_Op
then
329 return Present
(Universal_Interpretation
(Left_Opnd
(N
)))
330 and then Present
(Universal_Interpretation
(Right_Opnd
(N
)));
332 elsif Nkind
(N
) in N_Unary_Op
then
333 return Present
(Universal_Interpretation
(Right_Opnd
(N
)));
335 elsif Nkind
(N
) = N_Function_Call
then
336 Arg
:= First_Actual
(N
);
337 while Present
(Arg
) loop
338 if No
(Universal_Interpretation
(Arg
)) then
350 end Is_Universal_Operation
;
352 -- Start of processing for Add_One_Interp
355 -- If the interpretation is a predefined operator, verify that the
356 -- result type is visible, or that the entity has already been
357 -- resolved (case of an instantiation node that refers to a predefined
358 -- operation, or an internally generated operator node, or an operator
359 -- given as an expanded name). If the operator is a comparison or
360 -- equality, it is the type of the operand that matters to determine
361 -- whether the operator is visible. In an instance, the check is not
362 -- performed, given that the operator was visible in the generic.
364 if Ekind
(E
) = E_Operator
then
366 if Present
(Opnd_Type
) then
367 Vis_Type
:= Opnd_Type
;
369 Vis_Type
:= Base_Type
(T
);
372 if In_Open_Scopes
(Scope
(Vis_Type
))
373 or else Is_Potentially_Use_Visible
(Vis_Type
)
374 or else In_Use
(Vis_Type
)
375 or else (In_Use
(Scope
(Vis_Type
))
376 and then not Is_Hidden
(Vis_Type
))
377 or else Nkind
(N
) = N_Expanded_Name
378 or else (Nkind
(N
) in N_Op
and then E
= Entity
(N
))
380 or else Ekind
(Vis_Type
) = E_Anonymous_Access_Type
384 -- If the node is given in functional notation and the prefix
385 -- is an expanded name, then the operator is visible if the
386 -- prefix is the scope of the result type as well. If the
387 -- operator is (implicitly) defined in an extension of system,
388 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
390 elsif Nkind
(N
) = N_Function_Call
391 and then Nkind
(Name
(N
)) = N_Expanded_Name
392 and then (Entity
(Prefix
(Name
(N
))) = Scope
(Base_Type
(T
))
393 or else Entity
(Prefix
(Name
(N
))) = Scope
(Vis_Type
)
394 or else Scope
(Vis_Type
) = System_Aux_Id
)
398 -- Save type for subsequent error message, in case no other
399 -- interpretation is found.
402 Candidate_Type
:= Vis_Type
;
406 -- In an instance, an abstract non-dispatching operation cannot
407 -- be a candidate interpretation, because it could not have been
408 -- one in the generic (it may be a spurious overloading in the
412 and then Is_Overloadable
(E
)
413 and then Is_Abstract_Subprogram
(E
)
414 and then not Is_Dispatching_Operation
(E
)
418 -- An inherited interface operation that is implemented by some
419 -- derived type does not participate in overload resolution, only
420 -- the implementation operation does.
423 and then Is_Subprogram
(E
)
424 and then Present
(Abstract_Interface_Alias
(E
))
426 -- Ada 2005 (AI-251): If this primitive operation corresponds with
427 -- an immediate ancestor interface there is no need to add it to the
428 -- list of interpretations. The corresponding aliased primitive is
429 -- also in this list of primitive operations and will be used instead
430 -- because otherwise we have a dummy ambiguity between the two
431 -- subprograms which are in fact the same.
434 (Find_Dispatching_Type
(Abstract_Interface_Alias
(E
)),
435 Find_Dispatching_Type
(E
))
437 Add_One_Interp
(N
, Abstract_Interface_Alias
(E
), T
);
443 -- If this is the first interpretation of N, N has type Any_Type.
444 -- In that case place the new type on the node. If one interpretation
445 -- already exists, indicate that the node is overloaded, and store
446 -- both the previous and the new interpretation in All_Interp. If
447 -- this is a later interpretation, just add it to the set.
449 if Etype
(N
) = Any_Type
then
454 -- Record both the operator or subprogram name, and its type
456 if Nkind
(N
) in N_Op
or else Is_Entity_Name
(N
) then
463 -- Either there is no current interpretation in the table for any
464 -- node or the interpretation that is present is for a different
465 -- node. In both cases add a new interpretation to the table.
467 elsif Interp_Map
.Last
< 0
469 (Interp_Map
.Table
(Interp_Map
.Last
).Node
/= N
470 and then not Is_Overloaded
(N
))
474 if (Nkind
(N
) in N_Op
or else Is_Entity_Name
(N
))
475 and then Present
(Entity
(N
))
477 Add_Entry
(Entity
(N
), Etype
(N
));
479 elsif (Nkind
(N
) = N_Function_Call
480 or else Nkind
(N
) = N_Procedure_Call_Statement
)
481 and then (Nkind
(Name
(N
)) = N_Operator_Symbol
482 or else Is_Entity_Name
(Name
(N
)))
484 Add_Entry
(Entity
(Name
(N
)), Etype
(N
));
486 -- If this is an indirect call there will be no name associated
487 -- with the previous entry. To make diagnostics clearer, save
488 -- Subprogram_Type of first interpretation, so that the error will
489 -- point to the anonymous access to subprogram, not to the result
490 -- type of the call itself.
492 elsif (Nkind
(N
)) = N_Function_Call
493 and then Nkind
(Name
(N
)) = N_Explicit_Dereference
494 and then Is_Overloaded
(Name
(N
))
500 pragma Warnings
(Off
, Itn
);
503 Get_First_Interp
(Name
(N
), Itn
, It
);
504 Add_Entry
(It
.Nam
, Etype
(N
));
508 -- Overloaded prefix in indexed or selected component, or call
509 -- whose name is an expression or another call.
511 Add_Entry
(Etype
(N
), Etype
(N
));
525 procedure All_Overloads
is
527 for J
in All_Interp
.First
.. All_Interp
.Last
loop
529 if Present
(All_Interp
.Table
(J
).Nam
) then
530 Write_Entity_Info
(All_Interp
.Table
(J
). Nam
, " ");
532 Write_Str
("No Interp");
536 Write_Str
("=================");
541 --------------------------------------
542 -- Binary_Op_Interp_Has_Abstract_Op --
543 --------------------------------------
545 function Binary_Op_Interp_Has_Abstract_Op
547 E
: Entity_Id
) return Entity_Id
549 Abstr_Op
: Entity_Id
;
550 E_Left
: constant Node_Id
:= First_Formal
(E
);
551 E_Right
: constant Node_Id
:= Next_Formal
(E_Left
);
554 Abstr_Op
:= Has_Abstract_Op
(Left_Opnd
(N
), Etype
(E_Left
));
555 if Present
(Abstr_Op
) then
559 return Has_Abstract_Op
(Right_Opnd
(N
), Etype
(E_Right
));
560 end Binary_Op_Interp_Has_Abstract_Op
;
562 ---------------------
563 -- Collect_Interps --
564 ---------------------
566 procedure Collect_Interps
(N
: Node_Id
) is
567 Ent
: constant Entity_Id
:= Entity
(N
);
569 First_Interp
: Interp_Index
;
574 -- Unconditionally add the entity that was initially matched
576 First_Interp
:= All_Interp
.Last
;
577 Add_One_Interp
(N
, Ent
, Etype
(N
));
579 -- For expanded name, pick up all additional entities from the
580 -- same scope, since these are obviously also visible. Note that
581 -- these are not necessarily contiguous on the homonym chain.
583 if Nkind
(N
) = N_Expanded_Name
then
585 while Present
(H
) loop
586 if Scope
(H
) = Scope
(Entity
(N
)) then
587 Add_One_Interp
(N
, H
, Etype
(H
));
593 -- Case of direct name
596 -- First, search the homonym chain for directly visible entities
598 H
:= Current_Entity
(Ent
);
599 while Present
(H
) loop
600 exit when (not Is_Overloadable
(H
))
601 and then Is_Immediately_Visible
(H
);
603 if Is_Immediately_Visible
(H
)
606 -- Only add interpretation if not hidden by an inner
607 -- immediately visible one.
609 for J
in First_Interp
.. All_Interp
.Last
- 1 loop
611 -- Current homograph is not hidden. Add to overloads
613 if not Is_Immediately_Visible
(All_Interp
.Table
(J
).Nam
) then
616 -- Homograph is hidden, unless it is a predefined operator
618 elsif Type_Conformant
(H
, All_Interp
.Table
(J
).Nam
) then
620 -- A homograph in the same scope can occur within an
621 -- instantiation, the resulting ambiguity has to be
624 if Scope
(H
) = Scope
(Ent
)
626 and then not Is_Inherited_Operation
(H
)
628 All_Interp
.Table
(All_Interp
.Last
) :=
629 (H
, Etype
(H
), Empty
);
630 All_Interp
.Increment_Last
;
631 All_Interp
.Table
(All_Interp
.Last
) := No_Interp
;
634 elsif Scope
(H
) /= Standard_Standard
then
640 -- On exit, we know that current homograph is not hidden
642 Add_One_Interp
(N
, H
, Etype
(H
));
645 Write_Str
("Add overloaded interpretation ");
655 -- Scan list of homographs for use-visible entities only
657 H
:= Current_Entity
(Ent
);
659 while Present
(H
) loop
660 if Is_Potentially_Use_Visible
(H
)
662 and then Is_Overloadable
(H
)
664 for J
in First_Interp
.. All_Interp
.Last
- 1 loop
666 if not Is_Immediately_Visible
(All_Interp
.Table
(J
).Nam
) then
669 elsif Type_Conformant
(H
, All_Interp
.Table
(J
).Nam
) then
670 goto Next_Use_Homograph
;
674 Add_One_Interp
(N
, H
, Etype
(H
));
677 <<Next_Use_Homograph
>>
682 if All_Interp
.Last
= First_Interp
+ 1 then
684 -- The original interpretation is in fact not overloaded
686 Set_Is_Overloaded
(N
, False);
694 function Covers
(T1
, T2
: Entity_Id
) return Boolean is
699 function Full_View_Covers
(Typ1
, Typ2
: Entity_Id
) return Boolean;
700 -- In an instance the proper view may not always be correct for
701 -- private types, but private and full view are compatible. This
702 -- removes spurious errors from nested instantiations that involve,
703 -- among other things, types derived from private types.
705 ----------------------
706 -- Full_View_Covers --
707 ----------------------
709 function Full_View_Covers
(Typ1
, Typ2
: Entity_Id
) return Boolean is
712 Is_Private_Type
(Typ1
)
714 ((Present
(Full_View
(Typ1
))
715 and then Covers
(Full_View
(Typ1
), Typ2
))
716 or else Base_Type
(Typ1
) = Typ2
717 or else Base_Type
(Typ2
) = Typ1
);
718 end Full_View_Covers
;
720 -- Start of processing for Covers
723 -- If either operand missing, then this is an error, but ignore it (and
724 -- pretend we have a cover) if errors already detected, since this may
725 -- simply mean we have malformed trees.
727 if No
(T1
) or else No
(T2
) then
728 if Total_Errors_Detected
/= 0 then
735 BT1
:= Base_Type
(T1
);
736 BT2
:= Base_Type
(T2
);
739 -- Simplest case: same types are compatible, and types that have the
740 -- same base type and are not generic actuals are compatible. Generic
741 -- actuals belong to their class but are not compatible with other
742 -- types of their class, and in particular with other generic actuals.
743 -- They are however compatible with their own subtypes, and itypes
744 -- with the same base are compatible as well. Similarly, constrained
745 -- subtypes obtained from expressions of an unconstrained nominal type
746 -- are compatible with the base type (may lead to spurious ambiguities
747 -- in obscure cases ???)
749 -- Generic actuals require special treatment to avoid spurious ambi-
750 -- guities in an instance, when two formal types are instantiated with
751 -- the same actual, so that different subprograms end up with the same
752 -- signature in the instance.
761 if not Is_Generic_Actual_Type
(T1
) then
764 return (not Is_Generic_Actual_Type
(T2
)
765 or else Is_Itype
(T1
)
766 or else Is_Itype
(T2
)
767 or else Is_Constr_Subt_For_U_Nominal
(T1
)
768 or else Is_Constr_Subt_For_U_Nominal
(T2
)
769 or else Scope
(T1
) /= Scope
(T2
));
772 -- Literals are compatible with types in a given "class"
774 elsif (T2
= Universal_Integer
and then Is_Integer_Type
(T1
))
775 or else (T2
= Universal_Real
and then Is_Real_Type
(T1
))
776 or else (T2
= Universal_Fixed
and then Is_Fixed_Point_Type
(T1
))
777 or else (T2
= Any_Fixed
and then Is_Fixed_Point_Type
(T1
))
778 or else (T2
= Any_String
and then Is_String_Type
(T1
))
779 or else (T2
= Any_Character
and then Is_Character_Type
(T1
))
780 or else (T2
= Any_Access
and then Is_Access_Type
(T1
))
784 -- The context may be class wide
786 elsif Is_Class_Wide_Type
(T1
)
787 and then Is_Ancestor
(Root_Type
(T1
), T2
)
791 elsif Is_Class_Wide_Type
(T1
)
792 and then Is_Class_Wide_Type
(T2
)
793 and then Base_Type
(Etype
(T1
)) = Base_Type
(Etype
(T2
))
797 -- Ada 2005 (AI-345): A class-wide abstract interface type T1 covers a
798 -- task_type or protected_type implementing T1
800 elsif Ada_Version
>= Ada_05
801 and then Is_Class_Wide_Type
(T1
)
802 and then Is_Interface
(Etype
(T1
))
803 and then Is_Concurrent_Type
(T2
)
804 and then Interface_Present_In_Ancestor
805 (Typ
=> Base_Type
(T2
),
810 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
811 -- object T2 implementing T1
813 elsif Ada_Version
>= Ada_05
814 and then Is_Class_Wide_Type
(T1
)
815 and then Is_Interface
(Etype
(T1
))
816 and then Is_Tagged_Type
(T2
)
818 if Interface_Present_In_Ancestor
(Typ
=> T2
,
829 if Is_Concurrent_Type
(BT2
) then
830 E
:= Corresponding_Record_Type
(BT2
);
835 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
836 -- covers an object T2 that implements a direct derivation of T1.
837 -- Note: test for presence of E is defense against previous error.
840 and then Present
(Abstract_Interfaces
(E
))
842 Elmt
:= First_Elmt
(Abstract_Interfaces
(E
));
843 while Present
(Elmt
) loop
844 if Is_Ancestor
(Etype
(T1
), Node
(Elmt
)) then
852 -- We should also check the case in which T1 is an ancestor of
853 -- some implemented interface???
858 -- In a dispatching call the actual may be class-wide
860 elsif Is_Class_Wide_Type
(T2
)
861 and then Base_Type
(Root_Type
(T2
)) = Base_Type
(T1
)
865 -- Some contexts require a class of types rather than a specific type
867 elsif (T1
= Any_Integer
and then Is_Integer_Type
(T2
))
868 or else (T1
= Any_Boolean
and then Is_Boolean_Type
(T2
))
869 or else (T1
= Any_Real
and then Is_Real_Type
(T2
))
870 or else (T1
= Any_Fixed
and then Is_Fixed_Point_Type
(T2
))
871 or else (T1
= Any_Discrete
and then Is_Discrete_Type
(T2
))
875 -- An aggregate is compatible with an array or record type
877 elsif T2
= Any_Composite
878 and then Ekind
(T1
) in E_Array_Type
.. E_Record_Subtype
882 -- If the expected type is an anonymous access, the designated type must
883 -- cover that of the expression. Use the base type for this check: even
884 -- though access subtypes are rare in sources, they are generated for
885 -- actuals in instantiations.
887 elsif Ekind
(BT1
) = E_Anonymous_Access_Type
888 and then Is_Access_Type
(T2
)
889 and then Covers
(Designated_Type
(T1
), Designated_Type
(T2
))
893 -- An Access_To_Subprogram is compatible with itself, or with an
894 -- anonymous type created for an attribute reference Access.
896 elsif (Ekind
(BT1
) = E_Access_Subprogram_Type
898 Ekind
(BT1
) = E_Access_Protected_Subprogram_Type
)
899 and then Is_Access_Type
(T2
)
900 and then (not Comes_From_Source
(T1
)
901 or else not Comes_From_Source
(T2
))
902 and then (Is_Overloadable
(Designated_Type
(T2
))
904 Ekind
(Designated_Type
(T2
)) = E_Subprogram_Type
)
906 Type_Conformant
(Designated_Type
(T1
), Designated_Type
(T2
))
908 Mode_Conformant
(Designated_Type
(T1
), Designated_Type
(T2
))
912 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
913 -- with itself, or with an anonymous type created for an attribute
916 elsif (Ekind
(BT1
) = E_Anonymous_Access_Subprogram_Type
919 = E_Anonymous_Access_Protected_Subprogram_Type
)
920 and then Is_Access_Type
(T2
)
921 and then (not Comes_From_Source
(T1
)
922 or else not Comes_From_Source
(T2
))
923 and then (Is_Overloadable
(Designated_Type
(T2
))
925 Ekind
(Designated_Type
(T2
)) = E_Subprogram_Type
)
927 Type_Conformant
(Designated_Type
(T1
), Designated_Type
(T2
))
929 Mode_Conformant
(Designated_Type
(T1
), Designated_Type
(T2
))
933 -- The context can be a remote access type, and the expression the
934 -- corresponding source type declared in a categorized package, or
937 elsif Is_Record_Type
(T1
)
938 and then (Is_Remote_Call_Interface
(T1
)
939 or else Is_Remote_Types
(T1
))
940 and then Present
(Corresponding_Remote_Type
(T1
))
942 return Covers
(Corresponding_Remote_Type
(T1
), T2
);
944 elsif Is_Record_Type
(T2
)
945 and then (Is_Remote_Call_Interface
(T2
)
946 or else Is_Remote_Types
(T2
))
947 and then Present
(Corresponding_Remote_Type
(T2
))
949 return Covers
(Corresponding_Remote_Type
(T2
), T1
);
951 elsif Ekind
(T2
) = E_Access_Attribute_Type
952 and then (Ekind
(BT1
) = E_General_Access_Type
953 or else Ekind
(BT1
) = E_Access_Type
)
954 and then Covers
(Designated_Type
(T1
), Designated_Type
(T2
))
956 -- If the target type is a RACW type while the source is an access
957 -- attribute type, we are building a RACW that may be exported.
959 if Is_Remote_Access_To_Class_Wide_Type
(BT1
) then
960 Set_Has_RACW
(Current_Sem_Unit
);
965 elsif Ekind
(T2
) = E_Allocator_Type
966 and then Is_Access_Type
(T1
)
968 return Covers
(Designated_Type
(T1
), Designated_Type
(T2
))
970 (From_With_Type
(Designated_Type
(T1
))
971 and then Covers
(Designated_Type
(T2
), Designated_Type
(T1
)));
973 -- A boolean operation on integer literals is compatible with modular
976 elsif T2
= Any_Modular
977 and then Is_Modular_Integer_Type
(T1
)
981 -- The actual type may be the result of a previous error
983 elsif Base_Type
(T2
) = Any_Type
then
986 -- A packed array type covers its corresponding non-packed type. This is
987 -- not legitimate Ada, but allows the omission of a number of otherwise
988 -- useless unchecked conversions, and since this can only arise in
989 -- (known correct) expanded code, no harm is done
991 elsif Is_Array_Type
(T2
)
992 and then Is_Packed
(T2
)
993 and then T1
= Packed_Array_Type
(T2
)
997 -- Similarly an array type covers its corresponding packed array type
999 elsif Is_Array_Type
(T1
)
1000 and then Is_Packed
(T1
)
1001 and then T2
= Packed_Array_Type
(T1
)
1005 -- In instances, or with types exported from instantiations, check
1006 -- whether a partial and a full view match. Verify that types are
1007 -- legal, to prevent cascaded errors.
1011 (Full_View_Covers
(T1
, T2
)
1012 or else Full_View_Covers
(T2
, T1
))
1017 and then Is_Generic_Actual_Type
(T2
)
1018 and then Full_View_Covers
(T1
, T2
)
1023 and then Is_Generic_Actual_Type
(T1
)
1024 and then Full_View_Covers
(T2
, T1
)
1028 -- In the expansion of inlined bodies, types are compatible if they
1029 -- are structurally equivalent.
1031 elsif In_Inlined_Body
1032 and then (Underlying_Type
(T1
) = Underlying_Type
(T2
)
1033 or else (Is_Access_Type
(T1
)
1034 and then Is_Access_Type
(T2
)
1036 Designated_Type
(T1
) = Designated_Type
(T2
))
1037 or else (T1
= Any_Access
1038 and then Is_Access_Type
(Underlying_Type
(T2
)))
1039 or else (T2
= Any_Composite
1041 Is_Composite_Type
(Underlying_Type
(T1
))))
1045 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1046 -- compatible with its real entity.
1048 elsif From_With_Type
(T1
) then
1050 -- If the expected type is the non-limited view of a type, the
1051 -- expression may have the limited view. If that one in turn is
1052 -- incomplete, get full view if available.
1054 if Is_Incomplete_Type
(T1
) then
1055 return Covers
(Get_Full_View
(Non_Limited_View
(T1
)), T2
);
1057 elsif Ekind
(T1
) = E_Class_Wide_Type
then
1059 Covers
(Class_Wide_Type
(Non_Limited_View
(Etype
(T1
))), T2
);
1064 elsif From_With_Type
(T2
) then
1066 -- If units in the context have Limited_With clauses on each other,
1067 -- either type might have a limited view. Checks performed elsewhere
1068 -- verify that the context type is the non-limited view.
1070 if Is_Incomplete_Type
(T2
) then
1071 return Covers
(T1
, Get_Full_View
(Non_Limited_View
(T2
)));
1073 elsif Ekind
(T2
) = E_Class_Wide_Type
then
1075 Present
(Non_Limited_View
(Etype
(T2
)))
1077 Covers
(T1
, Class_Wide_Type
(Non_Limited_View
(Etype
(T2
))));
1082 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1084 elsif Ekind
(T1
) = E_Incomplete_Subtype
then
1085 return Covers
(Full_View
(Etype
(T1
)), T2
);
1087 elsif Ekind
(T2
) = E_Incomplete_Subtype
then
1088 return Covers
(T1
, Full_View
(Etype
(T2
)));
1090 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1091 -- and actual anonymous access types in the context of generic
1092 -- instantiation. We have the following situation:
1095 -- type Formal is private;
1096 -- Formal_Obj : access Formal; -- T1
1100 -- type Actual is ...
1101 -- Actual_Obj : access Actual; -- T2
1102 -- package Instance is new G (Formal => Actual,
1103 -- Formal_Obj => Actual_Obj);
1105 elsif Ada_Version
>= Ada_05
1106 and then Ekind
(T1
) = E_Anonymous_Access_Type
1107 and then Ekind
(T2
) = E_Anonymous_Access_Type
1108 and then Is_Generic_Type
(Directly_Designated_Type
(T1
))
1109 and then Get_Instance_Of
(Directly_Designated_Type
(T1
)) =
1110 Directly_Designated_Type
(T2
)
1114 -- Otherwise it doesn't cover!
1125 function Disambiguate
1127 I1
, I2
: Interp_Index
;
1134 Nam1
, Nam2
: Entity_Id
;
1135 Predef_Subp
: Entity_Id
;
1136 User_Subp
: Entity_Id
;
1138 function Inherited_From_Actual
(S
: Entity_Id
) return Boolean;
1139 -- Determine whether one of the candidates is an operation inherited by
1140 -- a type that is derived from an actual in an instantiation.
1142 function In_Generic_Actual
(Exp
: Node_Id
) return Boolean;
1143 -- Determine whether the expression is part of a generic actual. At
1144 -- the time the actual is resolved the scope is already that of the
1145 -- instance, but conceptually the resolution of the actual takes place
1146 -- in the enclosing context, and no special disambiguation rules should
1149 function Is_Actual_Subprogram
(S
: Entity_Id
) return Boolean;
1150 -- Determine whether a subprogram is an actual in an enclosing instance.
1151 -- An overloading between such a subprogram and one declared outside the
1152 -- instance is resolved in favor of the first, because it resolved in
1155 function Matches
(Actual
, Formal
: Node_Id
) return Boolean;
1156 -- Look for exact type match in an instance, to remove spurious
1157 -- ambiguities when two formal types have the same actual.
1159 function Standard_Operator
return Boolean;
1160 -- Check whether subprogram is predefined operator declared in Standard.
1161 -- It may given by an operator name, or by an expanded name whose prefix
1164 function Remove_Conversions
return Interp
;
1165 -- Last chance for pathological cases involving comparisons on literals,
1166 -- and user overloadings of the same operator. Such pathologies have
1167 -- been removed from the ACVC, but still appear in two DEC tests, with
1168 -- the following notable quote from Ben Brosgol:
1170 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1171 -- this example; Robert Dewar brought it to our attention, since it is
1172 -- apparently found in the ACVC 1.5. I did not attempt to find the
1173 -- reason in the Reference Manual that makes the example legal, since I
1174 -- was too nauseated by it to want to pursue it further.]
1176 -- Accordingly, this is not a fully recursive solution, but it handles
1177 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1178 -- pathology in the other direction with calls whose multiple overloaded
1179 -- actuals make them truly unresolvable.
1181 -- The new rules concerning abstract operations create additional need
1182 -- for special handling of expressions with universal operands, see
1183 -- comments to Has_Abstract_Interpretation below.
1185 ------------------------
1186 -- In_Generic_Actual --
1187 ------------------------
1189 function In_Generic_Actual
(Exp
: Node_Id
) return Boolean is
1190 Par
: constant Node_Id
:= Parent
(Exp
);
1196 elsif Nkind
(Par
) in N_Declaration
then
1197 if Nkind
(Par
) = N_Object_Declaration
1198 or else Nkind
(Par
) = N_Object_Renaming_Declaration
1200 return Present
(Corresponding_Generic_Association
(Par
));
1205 elsif Nkind
(Par
) in N_Statement_Other_Than_Procedure_Call
then
1209 return In_Generic_Actual
(Parent
(Par
));
1211 end In_Generic_Actual
;
1213 ---------------------------
1214 -- Inherited_From_Actual --
1215 ---------------------------
1217 function Inherited_From_Actual
(S
: Entity_Id
) return Boolean is
1218 Par
: constant Node_Id
:= Parent
(S
);
1220 if Nkind
(Par
) /= N_Full_Type_Declaration
1221 or else Nkind
(Type_Definition
(Par
)) /= N_Derived_Type_Definition
1225 return Is_Entity_Name
(Subtype_Indication
(Type_Definition
(Par
)))
1227 Is_Generic_Actual_Type
(
1228 Entity
(Subtype_Indication
(Type_Definition
(Par
))));
1230 end Inherited_From_Actual
;
1232 --------------------------
1233 -- Is_Actual_Subprogram --
1234 --------------------------
1236 function Is_Actual_Subprogram
(S
: Entity_Id
) return Boolean is
1238 return In_Open_Scopes
(Scope
(S
))
1240 (Is_Generic_Instance
(Scope
(S
))
1241 or else Is_Wrapper_Package
(Scope
(S
)));
1242 end Is_Actual_Subprogram
;
1248 function Matches
(Actual
, Formal
: Node_Id
) return Boolean is
1249 T1
: constant Entity_Id
:= Etype
(Actual
);
1250 T2
: constant Entity_Id
:= Etype
(Formal
);
1254 (Is_Numeric_Type
(T2
)
1256 (T1
= Universal_Real
or else T1
= Universal_Integer
));
1259 ------------------------
1260 -- Remove_Conversions --
1261 ------------------------
1263 function Remove_Conversions
return Interp
is
1271 function Has_Abstract_Interpretation
(N
: Node_Id
) return Boolean;
1272 -- If an operation has universal operands the universal operation
1273 -- is present among its interpretations. If there is an abstract
1274 -- interpretation for the operator, with a numeric result, this
1275 -- interpretation was already removed in sem_ch4, but the universal
1276 -- one is still visible. We must rescan the list of operators and
1277 -- remove the universal interpretation to resolve the ambiguity.
1279 ---------------------------------
1280 -- Has_Abstract_Interpretation --
1281 ---------------------------------
1283 function Has_Abstract_Interpretation
(N
: Node_Id
) return Boolean is
1287 if Nkind
(N
) not in N_Op
1288 or else Ada_Version
< Ada_05
1289 or else not Is_Overloaded
(N
)
1290 or else No
(Universal_Interpretation
(N
))
1295 E
:= Get_Name_Entity_Id
(Chars
(N
));
1296 while Present
(E
) loop
1297 if Is_Overloadable
(E
)
1298 and then Is_Abstract_Subprogram
(E
)
1299 and then Is_Numeric_Type
(Etype
(E
))
1307 -- Finally, if an operand of the binary operator is itself
1308 -- an operator, recurse to see whether its own abstract
1309 -- interpretation is responsible for the spurious ambiguity.
1311 if Nkind
(N
) in N_Binary_Op
then
1312 return Has_Abstract_Interpretation
(Left_Opnd
(N
))
1313 or else Has_Abstract_Interpretation
(Right_Opnd
(N
));
1315 elsif Nkind
(N
) in N_Unary_Op
then
1316 return Has_Abstract_Interpretation
(Right_Opnd
(N
));
1322 end Has_Abstract_Interpretation
;
1324 -- Start of processing for Remove_Conversions
1329 Get_First_Interp
(N
, I
, It
);
1330 while Present
(It
.Typ
) loop
1331 if not Is_Overloadable
(It
.Nam
) then
1335 F1
:= First_Formal
(It
.Nam
);
1341 if Nkind
(N
) = N_Function_Call
1342 or else Nkind
(N
) = N_Procedure_Call_Statement
1344 Act1
:= First_Actual
(N
);
1346 if Present
(Act1
) then
1347 Act2
:= Next_Actual
(Act1
);
1352 elsif Nkind
(N
) in N_Unary_Op
then
1353 Act1
:= Right_Opnd
(N
);
1356 elsif Nkind
(N
) in N_Binary_Op
then
1357 Act1
:= Left_Opnd
(N
);
1358 Act2
:= Right_Opnd
(N
);
1360 -- Use type of second formal, so as to include
1361 -- exponentiation, where the exponent may be
1362 -- ambiguous and the result non-universal.
1370 if Nkind
(Act1
) in N_Op
1371 and then Is_Overloaded
(Act1
)
1372 and then (Nkind
(Right_Opnd
(Act1
)) = N_Integer_Literal
1373 or else Nkind
(Right_Opnd
(Act1
)) = N_Real_Literal
)
1374 and then Has_Compatible_Type
(Act1
, Standard_Boolean
)
1375 and then Etype
(F1
) = Standard_Boolean
1377 -- If the two candidates are the original ones, the
1378 -- ambiguity is real. Otherwise keep the original, further
1379 -- calls to Disambiguate will take care of others in the
1380 -- list of candidates.
1382 if It1
/= No_Interp
then
1383 if It
= Disambiguate
.It1
1384 or else It
= Disambiguate
.It2
1386 if It1
= Disambiguate
.It1
1387 or else It1
= Disambiguate
.It2
1395 elsif Present
(Act2
)
1396 and then Nkind
(Act2
) in N_Op
1397 and then Is_Overloaded
(Act2
)
1398 and then (Nkind
(Right_Opnd
(Act2
)) = N_Integer_Literal
1400 Nkind
(Right_Opnd
(Act2
)) = N_Real_Literal
)
1401 and then Has_Compatible_Type
(Act2
, Standard_Boolean
)
1403 -- The preference rule on the first actual is not
1404 -- sufficient to disambiguate.
1412 elsif Is_Numeric_Type
(Etype
(F1
))
1414 (Has_Abstract_Interpretation
(Act1
)
1415 or else Has_Abstract_Interpretation
(Act2
))
1417 if It
= Disambiguate
.It1
then
1418 return Disambiguate
.It2
;
1419 elsif It
= Disambiguate
.It2
then
1420 return Disambiguate
.It1
;
1426 Get_Next_Interp
(I
, It
);
1429 -- After some error, a formal may have Any_Type and yield a spurious
1430 -- match. To avoid cascaded errors if possible, check for such a
1431 -- formal in either candidate.
1433 if Serious_Errors_Detected
> 0 then
1438 Formal
:= First_Formal
(Nam1
);
1439 while Present
(Formal
) loop
1440 if Etype
(Formal
) = Any_Type
then
1441 return Disambiguate
.It2
;
1444 Next_Formal
(Formal
);
1447 Formal
:= First_Formal
(Nam2
);
1448 while Present
(Formal
) loop
1449 if Etype
(Formal
) = Any_Type
then
1450 return Disambiguate
.It1
;
1453 Next_Formal
(Formal
);
1459 end Remove_Conversions
;
1461 -----------------------
1462 -- Standard_Operator --
1463 -----------------------
1465 function Standard_Operator
return Boolean is
1469 if Nkind
(N
) in N_Op
then
1472 elsif Nkind
(N
) = N_Function_Call
then
1475 if Nkind
(Nam
) /= N_Expanded_Name
then
1478 return Entity
(Prefix
(Nam
)) = Standard_Standard
;
1483 end Standard_Operator
;
1485 -- Start of processing for Disambiguate
1488 -- Recover the two legal interpretations
1490 Get_First_Interp
(N
, I
, It
);
1492 Get_Next_Interp
(I
, It
);
1498 Get_Next_Interp
(I
, It
);
1504 if Ada_Version
< Ada_05
then
1506 -- Check whether one of the entities is an Ada 2005 entity and we are
1507 -- operating in an earlier mode, in which case we discard the Ada
1508 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1510 if Is_Ada_2005_Only
(Nam1
) then
1512 elsif Is_Ada_2005_Only
(Nam2
) then
1517 -- Check for overloaded CIL convention stuff because the CIL libraries
1518 -- do sick things like Console.Write_Line where it matches
1519 -- two different overloads, so just pick the first ???
1521 if Convention
(Nam1
) = Convention_CIL
1522 and then Convention
(Nam2
) = Convention_CIL
1523 and then Ekind
(Nam1
) = Ekind
(Nam2
)
1524 and then (Ekind
(Nam1
) = E_Procedure
1525 or else Ekind
(Nam1
) = E_Function
)
1530 -- If the context is universal, the predefined operator is preferred.
1531 -- This includes bounds in numeric type declarations, and expressions
1532 -- in type conversions. If no interpretation yields a universal type,
1533 -- then we must check whether the user-defined entity hides the prede-
1536 if Chars
(Nam1
) in Any_Operator_Name
1537 and then Standard_Operator
1539 if Typ
= Universal_Integer
1540 or else Typ
= Universal_Real
1541 or else Typ
= Any_Integer
1542 or else Typ
= Any_Discrete
1543 or else Typ
= Any_Real
1544 or else Typ
= Any_Type
1546 -- Find an interpretation that yields the universal type, or else
1547 -- a predefined operator that yields a predefined numeric type.
1550 Candidate
: Interp
:= No_Interp
;
1553 Get_First_Interp
(N
, I
, It
);
1554 while Present
(It
.Typ
) loop
1555 if (Covers
(Typ
, It
.Typ
)
1556 or else Typ
= Any_Type
)
1558 (It
.Typ
= Universal_Integer
1559 or else It
.Typ
= Universal_Real
)
1563 elsif Covers
(Typ
, It
.Typ
)
1564 and then Scope
(It
.Typ
) = Standard_Standard
1565 and then Scope
(It
.Nam
) = Standard_Standard
1566 and then Is_Numeric_Type
(It
.Typ
)
1571 Get_Next_Interp
(I
, It
);
1574 if Candidate
/= No_Interp
then
1579 elsif Chars
(Nam1
) /= Name_Op_Not
1580 and then (Typ
= Standard_Boolean
or else Typ
= Any_Boolean
)
1582 -- Equality or comparison operation. Choose predefined operator if
1583 -- arguments are universal. The node may be an operator, name, or
1584 -- a function call, so unpack arguments accordingly.
1587 Arg1
, Arg2
: Node_Id
;
1590 if Nkind
(N
) in N_Op
then
1591 Arg1
:= Left_Opnd
(N
);
1592 Arg2
:= Right_Opnd
(N
);
1594 elsif Is_Entity_Name
(N
)
1595 or else Nkind
(N
) = N_Operator_Symbol
1597 Arg1
:= First_Entity
(Entity
(N
));
1598 Arg2
:= Next_Entity
(Arg1
);
1601 Arg1
:= First_Actual
(N
);
1602 Arg2
:= Next_Actual
(Arg1
);
1606 and then Present
(Universal_Interpretation
(Arg1
))
1607 and then Universal_Interpretation
(Arg2
) =
1608 Universal_Interpretation
(Arg1
)
1610 Get_First_Interp
(N
, I
, It
);
1611 while Scope
(It
.Nam
) /= Standard_Standard
loop
1612 Get_Next_Interp
(I
, It
);
1621 -- If no universal interpretation, check whether user-defined operator
1622 -- hides predefined one, as well as other special cases. If the node
1623 -- is a range, then one or both bounds are ambiguous. Each will have
1624 -- to be disambiguated w.r.t. the context type. The type of the range
1625 -- itself is imposed by the context, so we can return either legal
1628 if Ekind
(Nam1
) = E_Operator
then
1629 Predef_Subp
:= Nam1
;
1632 elsif Ekind
(Nam2
) = E_Operator
then
1633 Predef_Subp
:= Nam2
;
1636 elsif Nkind
(N
) = N_Range
then
1639 -- If two user defined-subprograms are visible, it is a true ambiguity,
1640 -- unless one of them is an entry and the context is a conditional or
1641 -- timed entry call, or unless we are within an instance and this is
1642 -- results from two formals types with the same actual.
1645 if Nkind
(N
) = N_Procedure_Call_Statement
1646 and then Nkind
(Parent
(N
)) = N_Entry_Call_Alternative
1647 and then N
= Entry_Call_Statement
(Parent
(N
))
1649 if Ekind
(Nam2
) = E_Entry
then
1651 elsif Ekind
(Nam1
) = E_Entry
then
1657 -- If the ambiguity occurs within an instance, it is due to several
1658 -- formal types with the same actual. Look for an exact match between
1659 -- the types of the formals of the overloadable entities, and the
1660 -- actuals in the call, to recover the unambiguous match in the
1661 -- original generic.
1663 -- The ambiguity can also be due to an overloading between a formal
1664 -- subprogram and a subprogram declared outside the generic. If the
1665 -- node is overloaded, it did not resolve to the global entity in
1666 -- the generic, and we choose the formal subprogram.
1668 -- Finally, the ambiguity can be between an explicit subprogram and
1669 -- one inherited (with different defaults) from an actual. In this
1670 -- case the resolution was to the explicit declaration in the
1671 -- generic, and remains so in the instance.
1674 and then not In_Generic_Actual
(N
)
1676 if Nkind
(N
) = N_Function_Call
1677 or else Nkind
(N
) = N_Procedure_Call_Statement
1682 Is_Act1
: constant Boolean := Is_Actual_Subprogram
(Nam1
);
1683 Is_Act2
: constant Boolean := Is_Actual_Subprogram
(Nam2
);
1686 if Is_Act1
and then not Is_Act2
then
1689 elsif Is_Act2
and then not Is_Act1
then
1692 elsif Inherited_From_Actual
(Nam1
)
1693 and then Comes_From_Source
(Nam2
)
1697 elsif Inherited_From_Actual
(Nam2
)
1698 and then Comes_From_Source
(Nam1
)
1703 Actual
:= First_Actual
(N
);
1704 Formal
:= First_Formal
(Nam1
);
1705 while Present
(Actual
) loop
1706 if Etype
(Actual
) /= Etype
(Formal
) then
1710 Next_Actual
(Actual
);
1711 Next_Formal
(Formal
);
1717 elsif Nkind
(N
) in N_Binary_Op
then
1718 if Matches
(Left_Opnd
(N
), First_Formal
(Nam1
))
1720 Matches
(Right_Opnd
(N
), Next_Formal
(First_Formal
(Nam1
)))
1727 elsif Nkind
(N
) in N_Unary_Op
then
1728 if Etype
(Right_Opnd
(N
)) = Etype
(First_Formal
(Nam1
)) then
1735 return Remove_Conversions
;
1738 return Remove_Conversions
;
1742 -- An implicit concatenation operator on a string type cannot be
1743 -- disambiguated from the predefined concatenation. This can only
1744 -- happen with concatenation of string literals.
1746 if Chars
(User_Subp
) = Name_Op_Concat
1747 and then Ekind
(User_Subp
) = E_Operator
1748 and then Is_String_Type
(Etype
(First_Formal
(User_Subp
)))
1752 -- If the user-defined operator is in an open scope, or in the scope
1753 -- of the resulting type, or given by an expanded name that names its
1754 -- scope, it hides the predefined operator for the type. Exponentiation
1755 -- has to be special-cased because the implicit operator does not have
1756 -- a symmetric signature, and may not be hidden by the explicit one.
1758 elsif (Nkind
(N
) = N_Function_Call
1759 and then Nkind
(Name
(N
)) = N_Expanded_Name
1760 and then (Chars
(Predef_Subp
) /= Name_Op_Expon
1761 or else Hides_Op
(User_Subp
, Predef_Subp
))
1762 and then Scope
(User_Subp
) = Entity
(Prefix
(Name
(N
))))
1763 or else Hides_Op
(User_Subp
, Predef_Subp
)
1765 if It1
.Nam
= User_Subp
then
1771 -- Otherwise, the predefined operator has precedence, or if the user-
1772 -- defined operation is directly visible we have a true ambiguity. If
1773 -- this is a fixed-point multiplication and division in Ada83 mode,
1774 -- exclude the universal_fixed operator, which often causes ambiguities
1778 if (In_Open_Scopes
(Scope
(User_Subp
))
1779 or else Is_Potentially_Use_Visible
(User_Subp
))
1780 and then not In_Instance
1782 if Is_Fixed_Point_Type
(Typ
)
1783 and then (Chars
(Nam1
) = Name_Op_Multiply
1784 or else Chars
(Nam1
) = Name_Op_Divide
)
1785 and then Ada_Version
= Ada_83
1787 if It2
.Nam
= Predef_Subp
then
1793 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1794 -- states that the operator defined in Standard is not available
1795 -- if there is a user-defined equality with the proper signature,
1796 -- declared in the same declarative list as the type. The node
1797 -- may be an operator or a function call.
1799 elsif (Chars
(Nam1
) = Name_Op_Eq
1801 Chars
(Nam1
) = Name_Op_Ne
)
1802 and then Ada_Version
>= Ada_05
1803 and then Etype
(User_Subp
) = Standard_Boolean
1808 if Nkind
(N
) = N_Function_Call
then
1809 Opnd
:= First_Actual
(N
);
1811 Opnd
:= Left_Opnd
(N
);
1814 if Ekind
(Etype
(Opnd
)) = E_Anonymous_Access_Type
1816 List_Containing
(Parent
(Designated_Type
(Etype
(Opnd
))))
1817 = List_Containing
(Unit_Declaration_Node
(User_Subp
))
1819 if It2
.Nam
= Predef_Subp
then
1825 return Remove_Conversions
;
1833 elsif It1
.Nam
= Predef_Subp
then
1842 ---------------------
1843 -- End_Interp_List --
1844 ---------------------
1846 procedure End_Interp_List
is
1848 All_Interp
.Table
(All_Interp
.Last
) := No_Interp
;
1849 All_Interp
.Increment_Last
;
1850 end End_Interp_List
;
1852 -------------------------
1853 -- Entity_Matches_Spec --
1854 -------------------------
1856 function Entity_Matches_Spec
(Old_S
, New_S
: Entity_Id
) return Boolean is
1858 -- Simple case: same entity kinds, type conformance is required. A
1859 -- parameterless function can also rename a literal.
1861 if Ekind
(Old_S
) = Ekind
(New_S
)
1862 or else (Ekind
(New_S
) = E_Function
1863 and then Ekind
(Old_S
) = E_Enumeration_Literal
)
1865 return Type_Conformant
(New_S
, Old_S
);
1867 elsif Ekind
(New_S
) = E_Function
1868 and then Ekind
(Old_S
) = E_Operator
1870 return Operator_Matches_Spec
(Old_S
, New_S
);
1872 elsif Ekind
(New_S
) = E_Procedure
1873 and then Is_Entry
(Old_S
)
1875 return Type_Conformant
(New_S
, Old_S
);
1880 end Entity_Matches_Spec
;
1882 ----------------------
1883 -- Find_Unique_Type --
1884 ----------------------
1886 function Find_Unique_Type
(L
: Node_Id
; R
: Node_Id
) return Entity_Id
is
1887 T
: constant Entity_Id
:= Etype
(L
);
1890 TR
: Entity_Id
:= Any_Type
;
1893 if Is_Overloaded
(R
) then
1894 Get_First_Interp
(R
, I
, It
);
1895 while Present
(It
.Typ
) loop
1896 if Covers
(T
, It
.Typ
) or else Covers
(It
.Typ
, T
) then
1898 -- If several interpretations are possible and L is universal,
1899 -- apply preference rule.
1901 if TR
/= Any_Type
then
1903 if (T
= Universal_Integer
or else T
= Universal_Real
)
1914 Get_Next_Interp
(I
, It
);
1919 -- In the non-overloaded case, the Etype of R is already set correctly
1925 -- If one of the operands is Universal_Fixed, the type of the other
1926 -- operand provides the context.
1928 if Etype
(R
) = Universal_Fixed
then
1931 elsif T
= Universal_Fixed
then
1934 -- Ada 2005 (AI-230): Support the following operators:
1936 -- function "=" (L, R : universal_access) return Boolean;
1937 -- function "/=" (L, R : universal_access) return Boolean;
1939 -- Pool specific access types (E_Access_Type) are not covered by these
1940 -- operators because of the legality rule of 4.5.2(9.2): "The operands
1941 -- of the equality operators for universal_access shall be convertible
1942 -- to one another (see 4.6)". For example, considering the type decla-
1943 -- ration "type P is access Integer" and an anonymous access to Integer,
1944 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
1945 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
1947 elsif Ada_Version
>= Ada_05
1949 (Ekind
(Etype
(L
)) = E_Anonymous_Access_Type
1951 Ekind
(Etype
(L
)) = E_Anonymous_Access_Subprogram_Type
)
1952 and then Is_Access_Type
(Etype
(R
))
1953 and then Ekind
(Etype
(R
)) /= E_Access_Type
1957 elsif Ada_Version
>= Ada_05
1959 (Ekind
(Etype
(R
)) = E_Anonymous_Access_Type
1960 or else Ekind
(Etype
(R
)) = E_Anonymous_Access_Subprogram_Type
)
1961 and then Is_Access_Type
(Etype
(L
))
1962 and then Ekind
(Etype
(L
)) /= E_Access_Type
1967 return Specific_Type
(T
, Etype
(R
));
1969 end Find_Unique_Type
;
1971 -------------------------------------
1972 -- Function_Interp_Has_Abstract_Op --
1973 -------------------------------------
1975 function Function_Interp_Has_Abstract_Op
1977 E
: Entity_Id
) return Entity_Id
1979 Abstr_Op
: Entity_Id
;
1982 Form_Parm
: Node_Id
;
1985 -- Why is check on E needed below ???
1986 -- In any case this para needs comments ???
1988 if Is_Overloaded
(N
) and then Is_Overloadable
(E
) then
1989 Act_Parm
:= First_Actual
(N
);
1990 Form_Parm
:= First_Formal
(E
);
1991 while Present
(Act_Parm
)
1992 and then Present
(Form_Parm
)
1996 if Nkind
(Act
) = N_Parameter_Association
then
1997 Act
:= Explicit_Actual_Parameter
(Act
);
2000 Abstr_Op
:= Has_Abstract_Op
(Act
, Etype
(Form_Parm
));
2002 if Present
(Abstr_Op
) then
2006 Next_Actual
(Act_Parm
);
2007 Next_Formal
(Form_Parm
);
2012 end Function_Interp_Has_Abstract_Op
;
2014 ----------------------
2015 -- Get_First_Interp --
2016 ----------------------
2018 procedure Get_First_Interp
2020 I
: out Interp_Index
;
2023 Int_Ind
: Interp_Index
;
2028 -- If a selected component is overloaded because the selector has
2029 -- multiple interpretations, the node is a call to a protected
2030 -- operation or an indirect call. Retrieve the interpretation from
2031 -- the selector name. The selected component may be overloaded as well
2032 -- if the prefix is overloaded. That case is unchanged.
2034 if Nkind
(N
) = N_Selected_Component
2035 and then Is_Overloaded
(Selector_Name
(N
))
2037 O_N
:= Selector_Name
(N
);
2042 Map_Ptr
:= Headers
(Hash
(O_N
));
2043 while Present
(Interp_Map
.Table
(Map_Ptr
).Node
) loop
2044 if Interp_Map
.Table
(Map_Ptr
).Node
= O_N
then
2045 Int_Ind
:= Interp_Map
.Table
(Map_Ptr
).Index
;
2046 It
:= All_Interp
.Table
(Int_Ind
);
2050 Map_Ptr
:= Interp_Map
.Table
(Map_Ptr
).Next
;
2054 -- Procedure should never be called if the node has no interpretations
2056 raise Program_Error
;
2057 end Get_First_Interp
;
2059 ---------------------
2060 -- Get_Next_Interp --
2061 ---------------------
2063 procedure Get_Next_Interp
(I
: in out Interp_Index
; It
: out Interp
) is
2066 It
:= All_Interp
.Table
(I
);
2067 end Get_Next_Interp
;
2069 -------------------------
2070 -- Has_Compatible_Type --
2071 -------------------------
2073 function Has_Compatible_Type
2086 if Nkind
(N
) = N_Subtype_Indication
2087 or else not Is_Overloaded
(N
)
2090 Covers
(Typ
, Etype
(N
))
2092 -- Ada 2005 (AI-345) The context may be a synchronized interface.
2093 -- If the type is already frozen use the corresponding_record
2094 -- to check whether it is a proper descendant.
2097 (Is_Concurrent_Type
(Etype
(N
))
2098 and then Present
(Corresponding_Record_Type
(Etype
(N
)))
2099 and then Covers
(Typ
, Corresponding_Record_Type
(Etype
(N
))))
2102 (not Is_Tagged_Type
(Typ
)
2103 and then Ekind
(Typ
) /= E_Anonymous_Access_Type
2104 and then Covers
(Etype
(N
), Typ
));
2107 Get_First_Interp
(N
, I
, It
);
2108 while Present
(It
.Typ
) loop
2109 if (Covers
(Typ
, It
.Typ
)
2111 (Scope
(It
.Nam
) /= Standard_Standard
2112 or else not Is_Invisible_Operator
(N
, Base_Type
(Typ
))))
2114 -- Ada 2005 (AI-345)
2117 (Is_Concurrent_Type
(It
.Typ
)
2118 and then Present
(Corresponding_Record_Type
2120 and then Covers
(Typ
, Corresponding_Record_Type
2123 or else (not Is_Tagged_Type
(Typ
)
2124 and then Ekind
(Typ
) /= E_Anonymous_Access_Type
2125 and then Covers
(It
.Typ
, Typ
))
2130 Get_Next_Interp
(I
, It
);
2135 end Has_Compatible_Type
;
2137 ---------------------
2138 -- Has_Abstract_Op --
2139 ---------------------
2141 function Has_Abstract_Op
2143 Typ
: Entity_Id
) return Entity_Id
2149 if Is_Overloaded
(N
) then
2150 Get_First_Interp
(N
, I
, It
);
2151 while Present
(It
.Nam
) loop
2152 if Present
(It
.Abstract_Op
)
2153 and then Etype
(It
.Abstract_Op
) = Typ
2155 return It
.Abstract_Op
;
2158 Get_Next_Interp
(I
, It
);
2163 end Has_Abstract_Op
;
2169 function Hash
(N
: Node_Id
) return Int
is
2171 -- Nodes have a size that is power of two, so to select significant
2172 -- bits only we remove the low-order bits.
2174 return ((Int
(N
) / 2 ** 5) mod Header_Size
);
2181 function Hides_Op
(F
: Entity_Id
; Op
: Entity_Id
) return Boolean is
2182 Btyp
: constant Entity_Id
:= Base_Type
(Etype
(First_Formal
(F
)));
2184 return Operator_Matches_Spec
(Op
, F
)
2185 and then (In_Open_Scopes
(Scope
(F
))
2186 or else Scope
(F
) = Scope
(Btyp
)
2187 or else (not In_Open_Scopes
(Scope
(Btyp
))
2188 and then not In_Use
(Btyp
)
2189 and then not In_Use
(Scope
(Btyp
))));
2192 ------------------------
2193 -- Init_Interp_Tables --
2194 ------------------------
2196 procedure Init_Interp_Tables
is
2200 Headers
:= (others => No_Entry
);
2201 end Init_Interp_Tables
;
2203 -----------------------------------
2204 -- Interface_Present_In_Ancestor --
2205 -----------------------------------
2207 function Interface_Present_In_Ancestor
2209 Iface
: Entity_Id
) return Boolean
2211 Target_Typ
: Entity_Id
;
2212 Iface_Typ
: Entity_Id
;
2214 function Iface_Present_In_Ancestor
(Typ
: Entity_Id
) return Boolean;
2215 -- Returns True if Typ or some ancestor of Typ implements Iface
2217 -------------------------------
2218 -- Iface_Present_In_Ancestor --
2219 -------------------------------
2221 function Iface_Present_In_Ancestor
(Typ
: Entity_Id
) return Boolean is
2227 if Typ
= Iface_Typ
then
2231 -- Handle private types
2233 if Present
(Full_View
(Typ
))
2234 and then not Is_Concurrent_Type
(Full_View
(Typ
))
2236 E
:= Full_View
(Typ
);
2242 if Present
(Abstract_Interfaces
(E
))
2243 and then Present
(Abstract_Interfaces
(E
))
2244 and then not Is_Empty_Elmt_List
(Abstract_Interfaces
(E
))
2246 Elmt
:= First_Elmt
(Abstract_Interfaces
(E
));
2247 while Present
(Elmt
) loop
2250 if AI
= Iface_Typ
or else Is_Ancestor
(Iface_Typ
, AI
) then
2258 exit when Etype
(E
) = E
2260 -- Handle private types
2262 or else (Present
(Full_View
(Etype
(E
)))
2263 and then Full_View
(Etype
(E
)) = E
);
2265 -- Check if the current type is a direct derivation of the
2268 if Etype
(E
) = Iface_Typ
then
2272 -- Climb to the immediate ancestor handling private types
2274 if Present
(Full_View
(Etype
(E
))) then
2275 E
:= Full_View
(Etype
(E
));
2282 end Iface_Present_In_Ancestor
;
2284 -- Start of processing for Interface_Present_In_Ancestor
2287 if Is_Class_Wide_Type
(Iface
) then
2288 Iface_Typ
:= Etype
(Iface
);
2295 Iface_Typ
:= Base_Type
(Iface_Typ
);
2297 if Is_Access_Type
(Typ
) then
2298 Target_Typ
:= Etype
(Directly_Designated_Type
(Typ
));
2303 if Is_Concurrent_Record_Type
(Target_Typ
) then
2304 Target_Typ
:= Corresponding_Concurrent_Type
(Target_Typ
);
2307 Target_Typ
:= Base_Type
(Target_Typ
);
2309 -- In case of concurrent types we can't use the Corresponding Record_Typ
2310 -- to look for the interface because it is built by the expander (and
2311 -- hence it is not always available). For this reason we traverse the
2312 -- list of interfaces (available in the parent of the concurrent type)
2314 if Is_Concurrent_Type
(Target_Typ
) then
2315 if Present
(Interface_List
(Parent
(Target_Typ
))) then
2320 AI
:= First
(Interface_List
(Parent
(Target_Typ
)));
2321 while Present
(AI
) loop
2322 if Etype
(AI
) = Iface_Typ
then
2325 elsif Present
(Abstract_Interfaces
(Etype
(AI
)))
2326 and then Iface_Present_In_Ancestor
(Etype
(AI
))
2339 if Is_Class_Wide_Type
(Target_Typ
) then
2340 Target_Typ
:= Etype
(Target_Typ
);
2343 if Ekind
(Target_Typ
) = E_Incomplete_Type
then
2344 pragma Assert
(Present
(Non_Limited_View
(Target_Typ
)));
2345 Target_Typ
:= Non_Limited_View
(Target_Typ
);
2347 -- Protect the frontend against previously detected errors
2349 if Ekind
(Target_Typ
) = E_Incomplete_Type
then
2354 return Iface_Present_In_Ancestor
(Target_Typ
);
2355 end Interface_Present_In_Ancestor
;
2357 ---------------------
2358 -- Intersect_Types --
2359 ---------------------
2361 function Intersect_Types
(L
, R
: Node_Id
) return Entity_Id
is
2362 Index
: Interp_Index
;
2366 function Check_Right_Argument
(T
: Entity_Id
) return Entity_Id
;
2367 -- Find interpretation of right arg that has type compatible with T
2369 --------------------------
2370 -- Check_Right_Argument --
2371 --------------------------
2373 function Check_Right_Argument
(T
: Entity_Id
) return Entity_Id
is
2374 Index
: Interp_Index
;
2379 if not Is_Overloaded
(R
) then
2380 return Specific_Type
(T
, Etype
(R
));
2383 Get_First_Interp
(R
, Index
, It
);
2385 T2
:= Specific_Type
(T
, It
.Typ
);
2387 if T2
/= Any_Type
then
2391 Get_Next_Interp
(Index
, It
);
2392 exit when No
(It
.Typ
);
2397 end Check_Right_Argument
;
2399 -- Start processing for Intersect_Types
2402 if Etype
(L
) = Any_Type
or else Etype
(R
) = Any_Type
then
2406 if not Is_Overloaded
(L
) then
2407 Typ
:= Check_Right_Argument
(Etype
(L
));
2411 Get_First_Interp
(L
, Index
, It
);
2412 while Present
(It
.Typ
) loop
2413 Typ
:= Check_Right_Argument
(It
.Typ
);
2414 exit when Typ
/= Any_Type
;
2415 Get_Next_Interp
(Index
, It
);
2420 -- If Typ is Any_Type, it means no compatible pair of types was found
2422 if Typ
= Any_Type
then
2423 if Nkind
(Parent
(L
)) in N_Op
then
2424 Error_Msg_N
("incompatible types for operator", Parent
(L
));
2426 elsif Nkind
(Parent
(L
)) = N_Range
then
2427 Error_Msg_N
("incompatible types given in constraint", Parent
(L
));
2429 -- Ada 2005 (AI-251): Complete the error notification
2431 elsif Is_Class_Wide_Type
(Etype
(R
))
2432 and then Is_Interface
(Etype
(Class_Wide_Type
(Etype
(R
))))
2434 Error_Msg_NE
("(Ada 2005) does not implement interface }",
2435 L
, Etype
(Class_Wide_Type
(Etype
(R
))));
2438 Error_Msg_N
("incompatible types", Parent
(L
));
2443 end Intersect_Types
;
2449 function Is_Ancestor
(T1
, T2
: Entity_Id
) return Boolean is
2453 if Base_Type
(T1
) = Base_Type
(T2
) then
2456 elsif Is_Private_Type
(T1
)
2457 and then Present
(Full_View
(T1
))
2458 and then Base_Type
(T2
) = Base_Type
(Full_View
(T1
))
2466 -- If there was a error on the type declaration, do not recurse
2468 if Error_Posted
(Par
) then
2471 elsif Base_Type
(T1
) = Base_Type
(Par
)
2472 or else (Is_Private_Type
(T1
)
2473 and then Present
(Full_View
(T1
))
2474 and then Base_Type
(Par
) = Base_Type
(Full_View
(T1
)))
2478 elsif Is_Private_Type
(Par
)
2479 and then Present
(Full_View
(Par
))
2480 and then Full_View
(Par
) = Base_Type
(T1
)
2484 elsif Etype
(Par
) /= Par
then
2493 ---------------------------
2494 -- Is_Invisible_Operator --
2495 ---------------------------
2497 function Is_Invisible_Operator
2502 Orig_Node
: constant Node_Id
:= Original_Node
(N
);
2505 if Nkind
(N
) not in N_Op
then
2508 elsif not Comes_From_Source
(N
) then
2511 elsif No
(Universal_Interpretation
(Right_Opnd
(N
))) then
2514 elsif Nkind
(N
) in N_Binary_Op
2515 and then No
(Universal_Interpretation
(Left_Opnd
(N
)))
2520 return Is_Numeric_Type
(T
)
2521 and then not In_Open_Scopes
(Scope
(T
))
2522 and then not Is_Potentially_Use_Visible
(T
)
2523 and then not In_Use
(T
)
2524 and then not In_Use
(Scope
(T
))
2526 (Nkind
(Orig_Node
) /= N_Function_Call
2527 or else Nkind
(Name
(Orig_Node
)) /= N_Expanded_Name
2528 or else Entity
(Prefix
(Name
(Orig_Node
))) /= Scope
(T
))
2529 and then not In_Instance
;
2531 end Is_Invisible_Operator
;
2537 function Is_Subtype_Of
(T1
: Entity_Id
; T2
: Entity_Id
) return Boolean is
2541 S
:= Ancestor_Subtype
(T1
);
2542 while Present
(S
) loop
2546 S
:= Ancestor_Subtype
(S
);
2557 procedure List_Interps
(Nam
: Node_Id
; Err
: Node_Id
) is
2558 Index
: Interp_Index
;
2562 Get_First_Interp
(Nam
, Index
, It
);
2563 while Present
(It
.Nam
) loop
2564 if Scope
(It
.Nam
) = Standard_Standard
2565 and then Scope
(It
.Typ
) /= Standard_Standard
2567 Error_Msg_Sloc
:= Sloc
(Parent
(It
.Typ
));
2568 Error_Msg_NE
("\\& (inherited) declared#!", Err
, It
.Nam
);
2571 Error_Msg_Sloc
:= Sloc
(It
.Nam
);
2572 Error_Msg_NE
("\\& declared#!", Err
, It
.Nam
);
2575 Get_Next_Interp
(Index
, It
);
2583 procedure New_Interps
(N
: Node_Id
) is
2587 All_Interp
.Increment_Last
;
2588 All_Interp
.Table
(All_Interp
.Last
) := No_Interp
;
2590 Map_Ptr
:= Headers
(Hash
(N
));
2592 if Map_Ptr
= No_Entry
then
2594 -- Place new node at end of table
2596 Interp_Map
.Increment_Last
;
2597 Headers
(Hash
(N
)) := Interp_Map
.Last
;
2600 -- Place node at end of chain, or locate its previous entry
2603 if Interp_Map
.Table
(Map_Ptr
).Node
= N
then
2605 -- Node is already in the table, and is being rewritten.
2606 -- Start a new interp section, retain hash link.
2608 Interp_Map
.Table
(Map_Ptr
).Node
:= N
;
2609 Interp_Map
.Table
(Map_Ptr
).Index
:= All_Interp
.Last
;
2610 Set_Is_Overloaded
(N
, True);
2614 exit when Interp_Map
.Table
(Map_Ptr
).Next
= No_Entry
;
2615 Map_Ptr
:= Interp_Map
.Table
(Map_Ptr
).Next
;
2619 -- Chain the new node
2621 Interp_Map
.Increment_Last
;
2622 Interp_Map
.Table
(Map_Ptr
).Next
:= Interp_Map
.Last
;
2625 Interp_Map
.Table
(Interp_Map
.Last
) := (N
, All_Interp
.Last
, No_Entry
);
2626 Set_Is_Overloaded
(N
, True);
2629 ---------------------------
2630 -- Operator_Matches_Spec --
2631 ---------------------------
2633 function Operator_Matches_Spec
(Op
, New_S
: Entity_Id
) return Boolean is
2634 Op_Name
: constant Name_Id
:= Chars
(Op
);
2635 T
: constant Entity_Id
:= Etype
(New_S
);
2643 -- To verify that a predefined operator matches a given signature,
2644 -- do a case analysis of the operator classes. Function can have one
2645 -- or two formals and must have the proper result type.
2647 New_F
:= First_Formal
(New_S
);
2648 Old_F
:= First_Formal
(Op
);
2650 while Present
(New_F
) and then Present
(Old_F
) loop
2652 Next_Formal
(New_F
);
2653 Next_Formal
(Old_F
);
2656 -- Definite mismatch if different number of parameters
2658 if Present
(Old_F
) or else Present
(New_F
) then
2664 T1
:= Etype
(First_Formal
(New_S
));
2666 if Op_Name
= Name_Op_Subtract
2667 or else Op_Name
= Name_Op_Add
2668 or else Op_Name
= Name_Op_Abs
2670 return Base_Type
(T1
) = Base_Type
(T
)
2671 and then Is_Numeric_Type
(T
);
2673 elsif Op_Name
= Name_Op_Not
then
2674 return Base_Type
(T1
) = Base_Type
(T
)
2675 and then Valid_Boolean_Arg
(Base_Type
(T
));
2684 T1
:= Etype
(First_Formal
(New_S
));
2685 T2
:= Etype
(Next_Formal
(First_Formal
(New_S
)));
2687 if Op_Name
= Name_Op_And
or else Op_Name
= Name_Op_Or
2688 or else Op_Name
= Name_Op_Xor
2690 return Base_Type
(T1
) = Base_Type
(T2
)
2691 and then Base_Type
(T1
) = Base_Type
(T
)
2692 and then Valid_Boolean_Arg
(Base_Type
(T
));
2694 elsif Op_Name
= Name_Op_Eq
or else Op_Name
= Name_Op_Ne
then
2695 return Base_Type
(T1
) = Base_Type
(T2
)
2696 and then not Is_Limited_Type
(T1
)
2697 and then Is_Boolean_Type
(T
);
2699 elsif Op_Name
= Name_Op_Lt
or else Op_Name
= Name_Op_Le
2700 or else Op_Name
= Name_Op_Gt
or else Op_Name
= Name_Op_Ge
2702 return Base_Type
(T1
) = Base_Type
(T2
)
2703 and then Valid_Comparison_Arg
(T1
)
2704 and then Is_Boolean_Type
(T
);
2706 elsif Op_Name
= Name_Op_Add
or else Op_Name
= Name_Op_Subtract
then
2707 return Base_Type
(T1
) = Base_Type
(T2
)
2708 and then Base_Type
(T1
) = Base_Type
(T
)
2709 and then Is_Numeric_Type
(T
);
2711 -- for division and multiplication, a user-defined function does
2712 -- not match the predefined universal_fixed operation, except in
2715 elsif Op_Name
= Name_Op_Divide
then
2716 return (Base_Type
(T1
) = Base_Type
(T2
)
2717 and then Base_Type
(T1
) = Base_Type
(T
)
2718 and then Is_Numeric_Type
(T
)
2719 and then (not Is_Fixed_Point_Type
(T
)
2720 or else Ada_Version
= Ada_83
))
2722 -- Mixed_Mode operations on fixed-point types
2724 or else (Base_Type
(T1
) = Base_Type
(T
)
2725 and then Base_Type
(T2
) = Base_Type
(Standard_Integer
)
2726 and then Is_Fixed_Point_Type
(T
))
2728 -- A user defined operator can also match (and hide) a mixed
2729 -- operation on universal literals.
2731 or else (Is_Integer_Type
(T2
)
2732 and then Is_Floating_Point_Type
(T1
)
2733 and then Base_Type
(T1
) = Base_Type
(T
));
2735 elsif Op_Name
= Name_Op_Multiply
then
2736 return (Base_Type
(T1
) = Base_Type
(T2
)
2737 and then Base_Type
(T1
) = Base_Type
(T
)
2738 and then Is_Numeric_Type
(T
)
2739 and then (not Is_Fixed_Point_Type
(T
)
2740 or else Ada_Version
= Ada_83
))
2742 -- Mixed_Mode operations on fixed-point types
2744 or else (Base_Type
(T1
) = Base_Type
(T
)
2745 and then Base_Type
(T2
) = Base_Type
(Standard_Integer
)
2746 and then Is_Fixed_Point_Type
(T
))
2748 or else (Base_Type
(T2
) = Base_Type
(T
)
2749 and then Base_Type
(T1
) = Base_Type
(Standard_Integer
)
2750 and then Is_Fixed_Point_Type
(T
))
2752 or else (Is_Integer_Type
(T2
)
2753 and then Is_Floating_Point_Type
(T1
)
2754 and then Base_Type
(T1
) = Base_Type
(T
))
2756 or else (Is_Integer_Type
(T1
)
2757 and then Is_Floating_Point_Type
(T2
)
2758 and then Base_Type
(T2
) = Base_Type
(T
));
2760 elsif Op_Name
= Name_Op_Mod
or else Op_Name
= Name_Op_Rem
then
2761 return Base_Type
(T1
) = Base_Type
(T2
)
2762 and then Base_Type
(T1
) = Base_Type
(T
)
2763 and then Is_Integer_Type
(T
);
2765 elsif Op_Name
= Name_Op_Expon
then
2766 return Base_Type
(T1
) = Base_Type
(T
)
2767 and then Is_Numeric_Type
(T
)
2768 and then Base_Type
(T2
) = Base_Type
(Standard_Integer
);
2770 elsif Op_Name
= Name_Op_Concat
then
2771 return Is_Array_Type
(T
)
2772 and then (Base_Type
(T
) = Base_Type
(Etype
(Op
)))
2773 and then (Base_Type
(T1
) = Base_Type
(T
)
2775 Base_Type
(T1
) = Base_Type
(Component_Type
(T
)))
2776 and then (Base_Type
(T2
) = Base_Type
(T
)
2778 Base_Type
(T2
) = Base_Type
(Component_Type
(T
)));
2784 end Operator_Matches_Spec
;
2790 procedure Remove_Interp
(I
: in out Interp_Index
) is
2794 -- Find end of Interp list and copy downward to erase the discarded one
2797 while Present
(All_Interp
.Table
(II
).Typ
) loop
2801 for J
in I
+ 1 .. II
loop
2802 All_Interp
.Table
(J
- 1) := All_Interp
.Table
(J
);
2805 -- Back up interp. index to insure that iterator will pick up next
2806 -- available interpretation.
2815 procedure Save_Interps
(Old_N
: Node_Id
; New_N
: Node_Id
) is
2817 O_N
: Node_Id
:= Old_N
;
2820 if Is_Overloaded
(Old_N
) then
2821 if Nkind
(Old_N
) = N_Selected_Component
2822 and then Is_Overloaded
(Selector_Name
(Old_N
))
2824 O_N
:= Selector_Name
(Old_N
);
2827 Map_Ptr
:= Headers
(Hash
(O_N
));
2829 while Interp_Map
.Table
(Map_Ptr
).Node
/= O_N
loop
2830 Map_Ptr
:= Interp_Map
.Table
(Map_Ptr
).Next
;
2831 pragma Assert
(Map_Ptr
/= No_Entry
);
2834 New_Interps
(New_N
);
2835 Interp_Map
.Table
(Interp_Map
.Last
).Index
:=
2836 Interp_Map
.Table
(Map_Ptr
).Index
;
2844 function Specific_Type
(Typ_1
, Typ_2
: Entity_Id
) return Entity_Id
is
2845 T1
: constant Entity_Id
:= Available_View
(Typ_1
);
2846 T2
: constant Entity_Id
:= Available_View
(Typ_2
);
2847 B1
: constant Entity_Id
:= Base_Type
(T1
);
2848 B2
: constant Entity_Id
:= Base_Type
(T2
);
2850 function Is_Remote_Access
(T
: Entity_Id
) return Boolean;
2851 -- Check whether T is the equivalent type of a remote access type.
2852 -- If distribution is enabled, T is a legal context for Null.
2854 ----------------------
2855 -- Is_Remote_Access --
2856 ----------------------
2858 function Is_Remote_Access
(T
: Entity_Id
) return Boolean is
2860 return Is_Record_Type
(T
)
2861 and then (Is_Remote_Call_Interface
(T
)
2862 or else Is_Remote_Types
(T
))
2863 and then Present
(Corresponding_Remote_Type
(T
))
2864 and then Is_Access_Type
(Corresponding_Remote_Type
(T
));
2865 end Is_Remote_Access
;
2867 -- Start of processing for Specific_Type
2870 if T1
= Any_Type
or else T2
= Any_Type
then
2877 elsif (T1
= Universal_Integer
and then Is_Integer_Type
(T2
))
2878 or else (T1
= Universal_Real
and then Is_Real_Type
(T2
))
2879 or else (T1
= Universal_Fixed
and then Is_Fixed_Point_Type
(T2
))
2880 or else (T1
= Any_Fixed
and then Is_Fixed_Point_Type
(T2
))
2884 elsif (T2
= Universal_Integer
and then Is_Integer_Type
(T1
))
2885 or else (T2
= Universal_Real
and then Is_Real_Type
(T1
))
2886 or else (T2
= Universal_Fixed
and then Is_Fixed_Point_Type
(T1
))
2887 or else (T2
= Any_Fixed
and then Is_Fixed_Point_Type
(T1
))
2891 elsif T2
= Any_String
and then Is_String_Type
(T1
) then
2894 elsif T1
= Any_String
and then Is_String_Type
(T2
) then
2897 elsif T2
= Any_Character
and then Is_Character_Type
(T1
) then
2900 elsif T1
= Any_Character
and then Is_Character_Type
(T2
) then
2903 elsif T1
= Any_Access
2904 and then (Is_Access_Type
(T2
) or else Is_Remote_Access
(T2
))
2908 elsif T2
= Any_Access
2909 and then (Is_Access_Type
(T1
) or else Is_Remote_Access
(T1
))
2913 elsif T2
= Any_Composite
2914 and then Ekind
(T1
) in E_Array_Type
.. E_Record_Subtype
2918 elsif T1
= Any_Composite
2919 and then Ekind
(T2
) in E_Array_Type
.. E_Record_Subtype
2923 elsif T1
= Any_Modular
and then Is_Modular_Integer_Type
(T2
) then
2926 elsif T2
= Any_Modular
and then Is_Modular_Integer_Type
(T1
) then
2929 -- ----------------------------------------------------------
2930 -- Special cases for equality operators (all other predefined
2931 -- operators can never apply to tagged types)
2932 -- ----------------------------------------------------------
2934 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
2937 elsif Is_Class_Wide_Type
(T1
)
2938 and then Is_Class_Wide_Type
(T2
)
2939 and then Is_Interface
(Etype
(T2
))
2943 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
2944 -- class-wide interface T2
2946 elsif Is_Class_Wide_Type
(T2
)
2947 and then Is_Interface
(Etype
(T2
))
2948 and then Interface_Present_In_Ancestor
(Typ
=> T1
,
2949 Iface
=> Etype
(T2
))
2953 elsif Is_Class_Wide_Type
(T1
)
2954 and then Is_Ancestor
(Root_Type
(T1
), T2
)
2958 elsif Is_Class_Wide_Type
(T2
)
2959 and then Is_Ancestor
(Root_Type
(T2
), T1
)
2963 elsif (Ekind
(B1
) = E_Access_Subprogram_Type
2965 Ekind
(B1
) = E_Access_Protected_Subprogram_Type
)
2966 and then Ekind
(Designated_Type
(B1
)) /= E_Subprogram_Type
2967 and then Is_Access_Type
(T2
)
2971 elsif (Ekind
(B2
) = E_Access_Subprogram_Type
2973 Ekind
(B2
) = E_Access_Protected_Subprogram_Type
)
2974 and then Ekind
(Designated_Type
(B2
)) /= E_Subprogram_Type
2975 and then Is_Access_Type
(T1
)
2979 elsif (Ekind
(T1
) = E_Allocator_Type
2980 or else Ekind
(T1
) = E_Access_Attribute_Type
2981 or else Ekind
(T1
) = E_Anonymous_Access_Type
)
2982 and then Is_Access_Type
(T2
)
2986 elsif (Ekind
(T2
) = E_Allocator_Type
2987 or else Ekind
(T2
) = E_Access_Attribute_Type
2988 or else Ekind
(T2
) = E_Anonymous_Access_Type
)
2989 and then Is_Access_Type
(T1
)
2993 -- If none of the above cases applies, types are not compatible
3000 ---------------------
3001 -- Set_Abstract_Op --
3002 ---------------------
3004 procedure Set_Abstract_Op
(I
: Interp_Index
; V
: Entity_Id
) is
3006 All_Interp
.Table
(I
).Abstract_Op
:= V
;
3007 end Set_Abstract_Op
;
3009 -----------------------
3010 -- Valid_Boolean_Arg --
3011 -----------------------
3013 -- In addition to booleans and arrays of booleans, we must include
3014 -- aggregates as valid boolean arguments, because in the first pass of
3015 -- resolution their components are not examined. If it turns out not to be
3016 -- an aggregate of booleans, this will be diagnosed in Resolve.
3017 -- Any_Composite must be checked for prior to the array type checks because
3018 -- Any_Composite does not have any associated indexes.
3020 function Valid_Boolean_Arg
(T
: Entity_Id
) return Boolean is
3022 return Is_Boolean_Type
(T
)
3023 or else T
= Any_Composite
3024 or else (Is_Array_Type
(T
)
3025 and then T
/= Any_String
3026 and then Number_Dimensions
(T
) = 1
3027 and then Is_Boolean_Type
(Component_Type
(T
))
3028 and then (not Is_Private_Composite
(T
)
3029 or else In_Instance
)
3030 and then (not Is_Limited_Composite
(T
)
3031 or else In_Instance
))
3032 or else Is_Modular_Integer_Type
(T
)
3033 or else T
= Universal_Integer
;
3034 end Valid_Boolean_Arg
;
3036 --------------------------
3037 -- Valid_Comparison_Arg --
3038 --------------------------
3040 function Valid_Comparison_Arg
(T
: Entity_Id
) return Boolean is
3043 if T
= Any_Composite
then
3045 elsif Is_Discrete_Type
(T
)
3046 or else Is_Real_Type
(T
)
3049 elsif Is_Array_Type
(T
)
3050 and then Number_Dimensions
(T
) = 1
3051 and then Is_Discrete_Type
(Component_Type
(T
))
3052 and then (not Is_Private_Composite
(T
)
3053 or else In_Instance
)
3054 and then (not Is_Limited_Composite
(T
)
3055 or else In_Instance
)
3058 elsif Is_String_Type
(T
) then
3063 end Valid_Comparison_Arg
;
3065 ----------------------
3066 -- Write_Interp_Ref --
3067 ----------------------
3069 procedure Write_Interp_Ref
(Map_Ptr
: Int
) is
3071 Write_Str
(" Node: ");
3072 Write_Int
(Int
(Interp_Map
.Table
(Map_Ptr
).Node
));
3073 Write_Str
(" Index: ");
3074 Write_Int
(Int
(Interp_Map
.Table
(Map_Ptr
).Index
));
3075 Write_Str
(" Next: ");
3076 Write_Int
(Int
(Interp_Map
.Table
(Map_Ptr
).Next
));
3078 end Write_Interp_Ref
;
3080 ---------------------
3081 -- Write_Overloads --
3082 ---------------------
3084 procedure Write_Overloads
(N
: Node_Id
) is
3090 if not Is_Overloaded
(N
) then
3091 Write_Str
("Non-overloaded entity ");
3093 Write_Entity_Info
(Entity
(N
), " ");
3096 Get_First_Interp
(N
, I
, It
);
3097 Write_Str
("Overloaded entity ");
3099 Write_Str
(" Name Type Abstract Op");
3101 Write_Str
("===============================================");
3105 while Present
(Nam
) loop
3106 Write_Int
(Int
(Nam
));
3108 Write_Name
(Chars
(Nam
));
3110 Write_Int
(Int
(It
.Typ
));
3112 Write_Name
(Chars
(It
.Typ
));
3114 if Present
(It
.Abstract_Op
) then
3116 Write_Int
(Int
(It
.Abstract_Op
));
3118 Write_Name
(Chars
(It
.Abstract_Op
));
3122 Get_Next_Interp
(I
, It
);
3126 end Write_Overloads
;