1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004 Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree; use Atree;
29 with Debug; use Debug;
30 with Einfo; use Einfo;
31 with Errout; use Errout;
34 with Output; use Output;
36 with Sem_Ch6; use Sem_Ch6;
37 with Sem_Ch8; use Sem_Ch8;
38 with Sem_Util; use Sem_Util;
39 with Stand; use Stand;
40 with Sinfo; use Sinfo;
41 with Snames; use Snames;
43 with Uintp; use Uintp;
45 package body Sem_Type is
51 -- The following data structures establish a mapping between nodes and
52 -- their interpretations. An overloaded node has an entry in Interp_Map,
53 -- which in turn contains a pointer into the All_Interp array. The
54 -- interpretations of a given node are contiguous in All_Interp. Each
55 -- set of interpretations is terminated with the marker No_Interp.
56 -- In order to speed up the retrieval of the interpretations of an
57 -- overloaded node, the Interp_Map table is accessed by means of a simple
58 -- hashing scheme, and the entries in Interp_Map are chained. The heads
59 -- of clash lists are stored in array Headers.
61 -- Headers Interp_Map All_Interp
63 -- _ ------- ----------
64 -- |_| |_____| --->|interp1 |
65 -- |_|---------->|node | | |interp2 |
66 -- |_| |index|---------| |nointerp|
71 -- This scheme does not currently reclaim interpretations. In principle,
72 -- after a unit is compiled, all overloadings have been resolved, and the
73 -- candidate interpretations should be deleted. This should be easier
74 -- now than with the previous scheme???
76 package All_Interp is new Table.Table (
77 Table_Component_Type => Interp,
78 Table_Index_Type => Int,
80 Table_Initial => Alloc.All_Interp_Initial,
81 Table_Increment => Alloc.All_Interp_Increment,
82 Table_Name => "All_Interp");
84 type Interp_Ref is record
90 Header_Size : constant Int := 2 ** 12;
91 No_Entry : constant Int := -1;
92 Headers : array (0 .. Header_Size) of Int := (others => No_Entry);
94 package Interp_Map is new Table.Table (
95 Table_Component_Type => Interp_Ref,
96 Table_Index_Type => Int,
98 Table_Initial => Alloc.Interp_Map_Initial,
99 Table_Increment => Alloc.Interp_Map_Increment,
100 Table_Name => "Interp_Map");
102 function Hash (N : Node_Id) return Int;
103 -- A trivial hashing function for nodes, used to insert an overloaded
104 -- node into the Interp_Map table.
106 -------------------------------------
107 -- Handling of Overload Resolution --
108 -------------------------------------
110 -- Overload resolution uses two passes over the syntax tree of a complete
111 -- context. In the first, bottom-up pass, the types of actuals in calls
112 -- are used to resolve possibly overloaded subprogram and operator names.
113 -- In the second top-down pass, the type of the context (for example the
114 -- condition in a while statement) is used to resolve a possibly ambiguous
115 -- call, and the unique subprogram name in turn imposes a specific context
116 -- on each of its actuals.
118 -- Most expressions are in fact unambiguous, and the bottom-up pass is
119 -- sufficient to resolve most everything. To simplify the common case,
120 -- names and expressions carry a flag Is_Overloaded to indicate whether
121 -- they have more than one interpretation. If the flag is off, then each
122 -- name has already a unique meaning and type, and the bottom-up pass is
123 -- sufficient (and much simpler).
125 --------------------------
126 -- Operator Overloading --
127 --------------------------
129 -- The visibility of operators is handled differently from that of
130 -- other entities. We do not introduce explicit versions of primitive
131 -- operators for each type definition. As a result, there is only one
132 -- entity corresponding to predefined addition on all numeric types, etc.
133 -- The back-end resolves predefined operators according to their type.
134 -- The visibility of primitive operations then reduces to the visibility
135 -- of the resulting type: (a + b) is a legal interpretation of some
136 -- primitive operator + if the type of the result (which must also be
137 -- the type of a and b) is directly visible (i.e. either immediately
138 -- visible or use-visible.)
140 -- User-defined operators are treated like other functions, but the
141 -- visibility of these user-defined operations must be special-cased
142 -- to determine whether they hide or are hidden by predefined operators.
143 -- The form P."+" (x, y) requires additional handling.
145 -- Concatenation is treated more conventionally: for every one-dimensional
146 -- array type we introduce a explicit concatenation operator. This is
147 -- necessary to handle the case of (element & element => array) which
148 -- cannot be handled conveniently if there is no explicit instance of
149 -- resulting type of the operation.
151 -----------------------
152 -- Local Subprograms --
153 -----------------------
155 procedure All_Overloads;
156 pragma Warnings (Off, All_Overloads);
157 -- Debugging procedure: list full contents of Overloads table.
159 procedure New_Interps (N : Node_Id);
160 -- Initialize collection of interpretations for the given node, which is
161 -- either an overloaded entity, or an operation whose arguments have
162 -- multiple intepretations. Interpretations can be added to only one
165 function Specific_Type (T1, T2 : Entity_Id) return Entity_Id;
166 -- If T1 and T2 are compatible, return the one that is not
167 -- universal or is not a "class" type (any_character, etc).
173 procedure Add_One_Interp
177 Opnd_Type : Entity_Id := Empty)
179 Vis_Type : Entity_Id;
181 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id);
182 -- Add one interpretation to node. Node is already known to be
183 -- overloaded. Add new interpretation if not hidden by previous
184 -- one, and remove previous one if hidden by new one.
186 function Is_Universal_Operation (Op : Entity_Id) return Boolean;
187 -- True if the entity is a predefined operator and the operands have
188 -- a universal Interpretation.
194 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id) is
195 Index : Interp_Index;
199 Get_First_Interp (N, Index, It);
201 while Present (It.Nam) loop
203 -- A user-defined subprogram hides another declared at an outer
204 -- level, or one that is use-visible. So return if previous
205 -- definition hides new one (which is either in an outer
206 -- scope, or use-visible). Note that for functions use-visible
207 -- is the same as potentially use-visible. If new one hides
208 -- previous one, replace entry in table of interpretations.
209 -- If this is a universal operation, retain the operator in case
210 -- preference rule applies.
212 if (((Ekind (Name) = E_Function or else Ekind (Name) = E_Procedure)
213 and then Ekind (Name) = Ekind (It.Nam))
214 or else (Ekind (Name) = E_Operator
215 and then Ekind (It.Nam) = E_Function))
217 and then Is_Immediately_Visible (It.Nam)
218 and then Type_Conformant (Name, It.Nam)
219 and then Base_Type (It.Typ) = Base_Type (T)
221 if Is_Universal_Operation (Name) then
224 -- If node is an operator symbol, we have no actuals with
225 -- which to check hiding, and this is done in full in the
226 -- caller (Analyze_Subprogram_Renaming) so we include the
227 -- predefined operator in any case.
229 elsif Nkind (N) = N_Operator_Symbol
230 or else (Nkind (N) = N_Expanded_Name
232 Nkind (Selector_Name (N)) = N_Operator_Symbol)
236 elsif not In_Open_Scopes (Scope (Name))
237 or else Scope_Depth (Scope (Name))
238 <= Scope_Depth (Scope (It.Nam))
240 -- If ambiguity within instance, and entity is not an
241 -- implicit operation, save for later disambiguation.
243 if Scope (Name) = Scope (It.Nam)
244 and then not Is_Inherited_Operation (Name)
253 All_Interp.Table (Index).Nam := Name;
257 -- Avoid making duplicate entries in overloads
260 and then Base_Type (It.Typ) = Base_Type (T)
264 -- Otherwise keep going
267 Get_Next_Interp (Index, It);
272 -- On exit, enter new interpretation. The context, or a preference
273 -- rule, will resolve the ambiguity on the second pass.
275 All_Interp.Table (All_Interp.Last) := (Name, Typ);
276 All_Interp.Increment_Last;
277 All_Interp.Table (All_Interp.Last) := No_Interp;
280 ----------------------------
281 -- Is_Universal_Operation --
282 ----------------------------
284 function Is_Universal_Operation (Op : Entity_Id) return Boolean is
288 if Ekind (Op) /= E_Operator then
291 elsif Nkind (N) in N_Binary_Op then
292 return Present (Universal_Interpretation (Left_Opnd (N)))
293 and then Present (Universal_Interpretation (Right_Opnd (N)));
295 elsif Nkind (N) in N_Unary_Op then
296 return Present (Universal_Interpretation (Right_Opnd (N)));
298 elsif Nkind (N) = N_Function_Call then
299 Arg := First_Actual (N);
301 while Present (Arg) loop
303 if No (Universal_Interpretation (Arg)) then
315 end Is_Universal_Operation;
317 -- Start of processing for Add_One_Interp
320 -- If the interpretation is a predefined operator, verify that the
321 -- result type is visible, or that the entity has already been
322 -- resolved (case of an instantiation node that refers to a predefined
323 -- operation, or an internally generated operator node, or an operator
324 -- given as an expanded name). If the operator is a comparison or
325 -- equality, it is the type of the operand that matters to determine
326 -- whether the operator is visible. In an instance, the check is not
327 -- performed, given that the operator was visible in the generic.
329 if Ekind (E) = E_Operator then
331 if Present (Opnd_Type) then
332 Vis_Type := Opnd_Type;
334 Vis_Type := Base_Type (T);
337 if In_Open_Scopes (Scope (Vis_Type))
338 or else Is_Potentially_Use_Visible (Vis_Type)
339 or else In_Use (Vis_Type)
340 or else (In_Use (Scope (Vis_Type))
341 and then not Is_Hidden (Vis_Type))
342 or else Nkind (N) = N_Expanded_Name
343 or else (Nkind (N) in N_Op and then E = Entity (N))
348 -- If the node is given in functional notation and the prefix
349 -- is an expanded name, then the operator is visible if the
350 -- prefix is the scope of the result type as well. If the
351 -- operator is (implicitly) defined in an extension of system,
352 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
354 elsif Nkind (N) = N_Function_Call
355 and then Nkind (Name (N)) = N_Expanded_Name
356 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
357 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
358 or else Scope (Vis_Type) = System_Aux_Id)
362 -- Save type for subsequent error message, in case no other
363 -- interpretation is found.
366 Candidate_Type := Vis_Type;
370 -- In an instance, an abstract non-dispatching operation cannot
371 -- be a candidate interpretation, because it could not have been
372 -- one in the generic (it may be a spurious overloading in the
376 and then Is_Abstract (E)
377 and then not Is_Dispatching_Operation (E)
382 -- If this is the first interpretation of N, N has type Any_Type.
383 -- In that case place the new type on the node. If one interpretation
384 -- already exists, indicate that the node is overloaded, and store
385 -- both the previous and the new interpretation in All_Interp. If
386 -- this is a later interpretation, just add it to the set.
388 if Etype (N) = Any_Type then
393 -- Record both the operator or subprogram name, and its type.
395 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
402 -- Either there is no current interpretation in the table for any
403 -- node or the interpretation that is present is for a different
404 -- node. In both cases add a new interpretation to the table.
406 elsif Interp_Map.Last < 0
408 (Interp_Map.Table (Interp_Map.Last).Node /= N
409 and then not Is_Overloaded (N))
413 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
414 and then Present (Entity (N))
416 Add_Entry (Entity (N), Etype (N));
418 elsif (Nkind (N) = N_Function_Call
419 or else Nkind (N) = N_Procedure_Call_Statement)
420 and then (Nkind (Name (N)) = N_Operator_Symbol
421 or else Is_Entity_Name (Name (N)))
423 Add_Entry (Entity (Name (N)), Etype (N));
426 -- Overloaded prefix in indexed or selected component,
427 -- or call whose name is an expresion or another call.
429 Add_Entry (Etype (N), Etype (N));
443 procedure All_Overloads is
445 for J in All_Interp.First .. All_Interp.Last loop
447 if Present (All_Interp.Table (J).Nam) then
448 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
450 Write_Str ("No Interp");
453 Write_Str ("=================");
458 ---------------------
459 -- Collect_Interps --
460 ---------------------
462 procedure Collect_Interps (N : Node_Id) is
463 Ent : constant Entity_Id := Entity (N);
465 First_Interp : Interp_Index;
470 -- Unconditionally add the entity that was initially matched
472 First_Interp := All_Interp.Last;
473 Add_One_Interp (N, Ent, Etype (N));
475 -- For expanded name, pick up all additional entities from the
476 -- same scope, since these are obviously also visible. Note that
477 -- these are not necessarily contiguous on the homonym chain.
479 if Nkind (N) = N_Expanded_Name then
481 while Present (H) loop
482 if Scope (H) = Scope (Entity (N)) then
483 Add_One_Interp (N, H, Etype (H));
489 -- Case of direct name
492 -- First, search the homonym chain for directly visible entities
494 H := Current_Entity (Ent);
495 while Present (H) loop
496 exit when (not Is_Overloadable (H))
497 and then Is_Immediately_Visible (H);
499 if Is_Immediately_Visible (H)
502 -- Only add interpretation if not hidden by an inner
503 -- immediately visible one.
505 for J in First_Interp .. All_Interp.Last - 1 loop
507 -- Current homograph is not hidden. Add to overloads.
509 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
512 -- Homograph is hidden, unless it is a predefined operator.
514 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
516 -- A homograph in the same scope can occur within an
517 -- instantiation, the resulting ambiguity has to be
520 if Scope (H) = Scope (Ent)
522 and then not Is_Inherited_Operation (H)
524 All_Interp.Table (All_Interp.Last) := (H, Etype (H));
525 All_Interp.Increment_Last;
526 All_Interp.Table (All_Interp.Last) := No_Interp;
529 elsif Scope (H) /= Standard_Standard then
535 -- On exit, we know that current homograph is not hidden.
537 Add_One_Interp (N, H, Etype (H));
540 Write_Str ("Add overloaded Interpretation ");
550 -- Scan list of homographs for use-visible entities only.
552 H := Current_Entity (Ent);
554 while Present (H) loop
555 if Is_Potentially_Use_Visible (H)
557 and then Is_Overloadable (H)
559 for J in First_Interp .. All_Interp.Last - 1 loop
561 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
564 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
565 goto Next_Use_Homograph;
569 Add_One_Interp (N, H, Etype (H));
572 <<Next_Use_Homograph>>
577 if All_Interp.Last = First_Interp + 1 then
579 -- The original interpretation is in fact not overloaded.
581 Set_Is_Overloaded (N, False);
589 function Covers (T1, T2 : Entity_Id) return Boolean is
591 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
592 -- In an instance the proper view may not always be correct for
593 -- private types, but private and full view are compatible. This
594 -- removes spurious errors from nested instantiations that involve,
595 -- among other things, types derived from private types.
597 ----------------------
598 -- Full_View_Covers --
599 ----------------------
601 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
604 Is_Private_Type (Typ1)
606 ((Present (Full_View (Typ1))
607 and then Covers (Full_View (Typ1), Typ2))
608 or else Base_Type (Typ1) = Typ2
609 or else Base_Type (Typ2) = Typ1);
610 end Full_View_Covers;
612 -- Start of processing for Covers
615 -- If either operand missing, then this is an error, but ignore
616 -- it (and pretend we have a cover) if errors already detected,
617 -- since this may simply mean we have malformed trees.
619 if No (T1) or else No (T2) then
620 if Total_Errors_Detected /= 0 then
627 -- Simplest case: same types are compatible, and types that have the
628 -- same base type and are not generic actuals are compatible. Generic
629 -- actuals belong to their class but are not compatible with other
630 -- types of their class, and in particular with other generic actuals.
631 -- They are however compatible with their own subtypes, and itypes
632 -- with the same base are compatible as well. Similary, constrained
633 -- subtypes obtained from expressions of an unconstrained nominal type
634 -- are compatible with the base type (may lead to spurious ambiguities
635 -- in obscure cases ???)
637 -- Generic actuals require special treatment to avoid spurious ambi-
638 -- guities in an instance, when two formal types are instantiated with
639 -- the same actual, so that different subprograms end up with the same
640 -- signature in the instance.
645 elsif Base_Type (T1) = Base_Type (T2) then
646 if not Is_Generic_Actual_Type (T1) then
649 return (not Is_Generic_Actual_Type (T2)
650 or else Is_Itype (T1)
651 or else Is_Itype (T2)
652 or else Is_Constr_Subt_For_U_Nominal (T1)
653 or else Is_Constr_Subt_For_U_Nominal (T2)
654 or else Scope (T1) /= Scope (T2));
657 -- Literals are compatible with types in a given "class"
659 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
660 or else (T2 = Universal_Real and then Is_Real_Type (T1))
661 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
662 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
663 or else (T2 = Any_String and then Is_String_Type (T1))
664 or else (T2 = Any_Character and then Is_Character_Type (T1))
665 or else (T2 = Any_Access and then Is_Access_Type (T1))
669 -- The context may be class wide.
671 elsif Is_Class_Wide_Type (T1)
672 and then Is_Ancestor (Root_Type (T1), T2)
676 elsif Is_Class_Wide_Type (T1)
677 and then Is_Class_Wide_Type (T2)
678 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
682 -- In a dispatching call the actual may be class-wide
684 elsif Is_Class_Wide_Type (T2)
685 and then Base_Type (Root_Type (T2)) = Base_Type (T1)
689 -- Some contexts require a class of types rather than a specific type
691 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
692 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
693 or else (T1 = Any_Real and then Is_Real_Type (T2))
694 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
695 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
699 -- An aggregate is compatible with an array or record type
701 elsif T2 = Any_Composite
702 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
706 -- If the expected type is an anonymous access, the designated
707 -- type must cover that of the expression.
709 elsif Ekind (T1) = E_Anonymous_Access_Type
710 and then Is_Access_Type (T2)
711 and then Covers (Designated_Type (T1), Designated_Type (T2))
715 -- An Access_To_Subprogram is compatible with itself, or with an
716 -- anonymous type created for an attribute reference Access.
718 elsif (Ekind (Base_Type (T1)) = E_Access_Subprogram_Type
720 Ekind (Base_Type (T1)) = E_Access_Protected_Subprogram_Type)
721 and then Is_Access_Type (T2)
722 and then (not Comes_From_Source (T1)
723 or else not Comes_From_Source (T2))
724 and then (Is_Overloadable (Designated_Type (T2))
726 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
728 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
730 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
734 -- Ada 0Y (AI-254): An Anonymous_Access_To_Subprogram is compatible with
735 -- itself, or with an anonymous type created for an attribute
738 elsif (Ekind (Base_Type (T1)) = E_Anonymous_Access_Subprogram_Type
740 Ekind (Base_Type (T1))
741 = E_Anonymous_Access_Protected_Subprogram_Type)
742 and then Is_Access_Type (T2)
743 and then (not Comes_From_Source (T1)
744 or else not Comes_From_Source (T2))
745 and then (Is_Overloadable (Designated_Type (T2))
747 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
749 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
751 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
755 -- The context can be a remote access type, and the expression the
756 -- corresponding source type declared in a categorized package, or
759 elsif Is_Record_Type (T1)
760 and then (Is_Remote_Call_Interface (T1)
761 or else Is_Remote_Types (T1))
762 and then Present (Corresponding_Remote_Type (T1))
764 return Covers (Corresponding_Remote_Type (T1), T2);
766 elsif Is_Record_Type (T2)
767 and then (Is_Remote_Call_Interface (T2)
768 or else Is_Remote_Types (T2))
769 and then Present (Corresponding_Remote_Type (T2))
771 return Covers (Corresponding_Remote_Type (T2), T1);
773 elsif Ekind (T2) = E_Access_Attribute_Type
774 and then (Ekind (Base_Type (T1)) = E_General_Access_Type
775 or else Ekind (Base_Type (T1)) = E_Access_Type)
776 and then Covers (Designated_Type (T1), Designated_Type (T2))
778 -- If the target type is a RACW type while the source is an access
779 -- attribute type, we are building a RACW that may be exported.
781 if Is_Remote_Access_To_Class_Wide_Type (Base_Type (T1)) then
782 Set_Has_RACW (Current_Sem_Unit);
787 elsif Ekind (T2) = E_Allocator_Type
788 and then Is_Access_Type (T1)
790 return Covers (Designated_Type (T1), Designated_Type (T2))
792 (From_With_Type (Designated_Type (T1))
793 and then Covers (Designated_Type (T2), Designated_Type (T1)));
795 -- A boolean operation on integer literals is compatible with a
798 elsif T2 = Any_Modular
799 and then Is_Modular_Integer_Type (T1)
803 -- The actual type may be the result of a previous error
805 elsif Base_Type (T2) = Any_Type then
808 -- A packed array type covers its corresponding non-packed type.
809 -- This is not legitimate Ada, but allows the omission of a number
810 -- of otherwise useless unchecked conversions, and since this can
811 -- only arise in (known correct) expanded code, no harm is done
813 elsif Is_Array_Type (T2)
814 and then Is_Packed (T2)
815 and then T1 = Packed_Array_Type (T2)
819 -- Similarly an array type covers its corresponding packed array type
821 elsif Is_Array_Type (T1)
822 and then Is_Packed (T1)
823 and then T2 = Packed_Array_Type (T1)
829 (Full_View_Covers (T1, T2)
830 or else Full_View_Covers (T2, T1))
834 -- In the expansion of inlined bodies, types are compatible if they
835 -- are structurally equivalent.
837 elsif In_Inlined_Body
838 and then (Underlying_Type (T1) = Underlying_Type (T2)
839 or else (Is_Access_Type (T1)
840 and then Is_Access_Type (T2)
842 Designated_Type (T1) = Designated_Type (T2))
843 or else (T1 = Any_Access
844 and then Is_Access_Type (Underlying_Type (T2))))
848 -- Ada 0Y (AI-50217): Additional branches to make the shadow entity
849 -- compatible with its real entity.
851 elsif From_With_Type (T1) then
853 -- If the expected type is the non-limited view of a type, the
854 -- expression may have the limited view.
856 if Ekind (T1) = E_Incomplete_Type then
857 return Covers (Non_Limited_View (T1), T2);
859 elsif Ekind (T1) = E_Class_Wide_Type then
861 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
866 elsif From_With_Type (T2) then
868 -- If units in the context have Limited_With clauses on each other,
869 -- either type might have a limited view. Checks performed elsewhere
870 -- verify that the context type is the non-limited view.
872 if Ekind (T2) = E_Incomplete_Type then
873 return Covers (T1, Non_Limited_View (T2));
875 elsif Ekind (T2) = E_Class_Wide_Type then
877 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
882 -- Otherwise it doesn't cover!
893 function Disambiguate
895 I1, I2 : Interp_Index;
902 Nam1, Nam2 : Entity_Id;
903 Predef_Subp : Entity_Id;
904 User_Subp : Entity_Id;
906 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
907 -- Determine whether a subprogram is an actual in an enclosing
908 -- instance. An overloading between such a subprogram and one
909 -- declared outside the instance is resolved in favor of the first,
910 -- because it resolved in the generic.
912 function Matches (Actual, Formal : Node_Id) return Boolean;
913 -- Look for exact type match in an instance, to remove spurious
914 -- ambiguities when two formal types have the same actual.
916 function Standard_Operator return Boolean;
918 function Remove_Conversions return Interp;
919 -- Last chance for pathological cases involving comparisons on
920 -- literals, and user overloadings of the same operator. Such
921 -- pathologies have been removed from the ACVC, but still appear in
922 -- two DEC tests, with the following notable quote from Ben Brosgol:
924 -- [Note: I disclaim all credit/responsibility/blame for coming up with
925 -- this example; Robert Dewar brought it to our attention, since it
926 -- is apparently found in the ACVC 1.5. I did not attempt to find
927 -- the reason in the Reference Manual that makes the example legal,
928 -- since I was too nauseated by it to want to pursue it further.]
930 -- Accordingly, this is not a fully recursive solution, but it handles
931 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
932 -- pathology in the other direction with calls whose multiple overloaded
933 -- actuals make them truly unresolvable.
935 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
937 return In_Open_Scopes (Scope (S))
939 (Is_Generic_Instance (Scope (S))
940 or else Is_Wrapper_Package (Scope (S)));
941 end Is_Actual_Subprogram;
947 function Matches (Actual, Formal : Node_Id) return Boolean is
948 T1 : constant Entity_Id := Etype (Actual);
949 T2 : constant Entity_Id := Etype (Formal);
954 (Is_Numeric_Type (T2)
956 (T1 = Universal_Real or else T1 = Universal_Integer));
959 ------------------------
960 -- Remove_Conversions --
961 ------------------------
963 function Remove_Conversions return Interp is
973 Get_First_Interp (N, I, It);
975 while Present (It.Typ) loop
977 if not Is_Overloadable (It.Nam) then
981 F1 := First_Formal (It.Nam);
987 if Nkind (N) = N_Function_Call
988 or else Nkind (N) = N_Procedure_Call_Statement
990 Act1 := First_Actual (N);
992 if Present (Act1) then
993 Act2 := Next_Actual (Act1);
998 elsif Nkind (N) in N_Unary_Op then
999 Act1 := Right_Opnd (N);
1002 elsif Nkind (N) in N_Binary_Op then
1003 Act1 := Left_Opnd (N);
1004 Act2 := Right_Opnd (N);
1010 if Nkind (Act1) in N_Op
1011 and then Is_Overloaded (Act1)
1012 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1013 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1014 and then Has_Compatible_Type (Act1, Standard_Boolean)
1015 and then Etype (F1) = Standard_Boolean
1017 -- If the two candidates are the original ones, the
1018 -- ambiguity is real. Otherwise keep the original,
1019 -- further calls to Disambiguate will take care of
1020 -- others in the list of candidates.
1022 if It1 /= No_Interp then
1023 if It = Disambiguate.It1
1024 or else It = Disambiguate.It2
1026 if It1 = Disambiguate.It1
1027 or else It1 = Disambiguate.It2
1035 elsif Present (Act2)
1036 and then Nkind (Act2) in N_Op
1037 and then Is_Overloaded (Act2)
1038 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1040 Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1041 and then Has_Compatible_Type (Act2, Standard_Boolean)
1043 -- The preference rule on the first actual is not
1044 -- sufficient to disambiguate.
1055 Get_Next_Interp (I, It);
1058 if Serious_Errors_Detected > 0 then
1060 -- After some error, a formal may have Any_Type and yield
1061 -- a spurious match. To avoid cascaded errors if possible,
1062 -- check for such a formal in either candidate.
1068 Formal := First_Formal (Nam1);
1069 while Present (Formal) loop
1070 if Etype (Formal) = Any_Type then
1071 return Disambiguate.It2;
1074 Next_Formal (Formal);
1077 Formal := First_Formal (Nam2);
1078 while Present (Formal) loop
1079 if Etype (Formal) = Any_Type then
1080 return Disambiguate.It1;
1083 Next_Formal (Formal);
1089 end Remove_Conversions;
1091 -----------------------
1092 -- Standard_Operator --
1093 -----------------------
1095 function Standard_Operator return Boolean is
1099 if Nkind (N) in N_Op then
1102 elsif Nkind (N) = N_Function_Call then
1105 if Nkind (Nam) /= N_Expanded_Name then
1108 return Entity (Prefix (Nam)) = Standard_Standard;
1113 end Standard_Operator;
1115 -- Start of processing for Disambiguate
1118 -- Recover the two legal interpretations.
1120 Get_First_Interp (N, I, It);
1123 Get_Next_Interp (I, It);
1130 Get_Next_Interp (I, It);
1136 -- If the context is universal, the predefined operator is preferred.
1137 -- This includes bounds in numeric type declarations, and expressions
1138 -- in type conversions. If no interpretation yields a universal type,
1139 -- then we must check whether the user-defined entity hides the prede-
1142 if Chars (Nam1) in Any_Operator_Name
1143 and then Standard_Operator
1145 if Typ = Universal_Integer
1146 or else Typ = Universal_Real
1147 or else Typ = Any_Integer
1148 or else Typ = Any_Discrete
1149 or else Typ = Any_Real
1150 or else Typ = Any_Type
1152 -- Find an interpretation that yields the universal type, or else
1153 -- a predefined operator that yields a predefined numeric type.
1156 Candidate : Interp := No_Interp;
1158 Get_First_Interp (N, I, It);
1160 while Present (It.Typ) loop
1161 if (Covers (Typ, It.Typ)
1162 or else Typ = Any_Type)
1164 (It.Typ = Universal_Integer
1165 or else It.Typ = Universal_Real)
1169 elsif Covers (Typ, It.Typ)
1170 and then Scope (It.Typ) = Standard_Standard
1171 and then Scope (It.Nam) = Standard_Standard
1172 and then Is_Numeric_Type (It.Typ)
1177 Get_Next_Interp (I, It);
1180 if Candidate /= No_Interp then
1185 elsif Chars (Nam1) /= Name_Op_Not
1186 and then (Typ = Standard_Boolean
1187 or else Typ = Any_Boolean)
1189 -- Equality or comparison operation. Choose predefined operator
1190 -- if arguments are universal. The node may be an operator, a
1191 -- name, or a function call, so unpack arguments accordingly.
1194 Arg1, Arg2 : Node_Id;
1197 if Nkind (N) in N_Op then
1198 Arg1 := Left_Opnd (N);
1199 Arg2 := Right_Opnd (N);
1201 elsif Is_Entity_Name (N)
1202 or else Nkind (N) = N_Operator_Symbol
1204 Arg1 := First_Entity (Entity (N));
1205 Arg2 := Next_Entity (Arg1);
1208 Arg1 := First_Actual (N);
1209 Arg2 := Next_Actual (Arg1);
1213 and then Present (Universal_Interpretation (Arg1))
1214 and then Universal_Interpretation (Arg2) =
1215 Universal_Interpretation (Arg1)
1217 Get_First_Interp (N, I, It);
1219 while Scope (It.Nam) /= Standard_Standard loop
1220 Get_Next_Interp (I, It);
1229 -- If no universal interpretation, check whether user-defined operator
1230 -- hides predefined one, as well as other special cases. If the node
1231 -- is a range, then one or both bounds are ambiguous. Each will have
1232 -- to be disambiguated w.r.t. the context type. The type of the range
1233 -- itself is imposed by the context, so we can return either legal
1236 if Ekind (Nam1) = E_Operator then
1237 Predef_Subp := Nam1;
1240 elsif Ekind (Nam2) = E_Operator then
1241 Predef_Subp := Nam2;
1244 elsif Nkind (N) = N_Range then
1247 -- If two user defined-subprograms are visible, it is a true ambiguity,
1248 -- unless one of them is an entry and the context is a conditional or
1249 -- timed entry call, or unless we are within an instance and this is
1250 -- results from two formals types with the same actual.
1253 if Nkind (N) = N_Procedure_Call_Statement
1254 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1255 and then N = Entry_Call_Statement (Parent (N))
1257 if Ekind (Nam2) = E_Entry then
1259 elsif Ekind (Nam1) = E_Entry then
1265 -- If the ambiguity occurs within an instance, it is due to several
1266 -- formal types with the same actual. Look for an exact match
1267 -- between the types of the formals of the overloadable entities,
1268 -- and the actuals in the call, to recover the unambiguous match
1269 -- in the original generic.
1271 -- The ambiguity can also be due to an overloading between a formal
1272 -- subprogram and a subprogram declared outside the generic. If the
1273 -- node is overloaded, it did not resolve to the global entity in
1274 -- the generic, and we choose the formal subprogram.
1276 elsif In_Instance then
1277 if Nkind (N) = N_Function_Call
1278 or else Nkind (N) = N_Procedure_Call_Statement
1283 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1284 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1287 if Is_Act1 and then not Is_Act2 then
1290 elsif Is_Act2 and then not Is_Act1 then
1294 Actual := First_Actual (N);
1295 Formal := First_Formal (Nam1);
1296 while Present (Actual) loop
1297 if Etype (Actual) /= Etype (Formal) then
1301 Next_Actual (Actual);
1302 Next_Formal (Formal);
1308 elsif Nkind (N) in N_Binary_Op then
1310 if Matches (Left_Opnd (N), First_Formal (Nam1))
1312 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1319 elsif Nkind (N) in N_Unary_Op then
1321 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1328 return Remove_Conversions;
1331 return Remove_Conversions;
1335 -- an implicit concatenation operator on a string type cannot be
1336 -- disambiguated from the predefined concatenation. This can only
1337 -- happen with concatenation of string literals.
1339 if Chars (User_Subp) = Name_Op_Concat
1340 and then Ekind (User_Subp) = E_Operator
1341 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1345 -- If the user-defined operator is in an open scope, or in the scope
1346 -- of the resulting type, or given by an expanded name that names its
1347 -- scope, it hides the predefined operator for the type. Exponentiation
1348 -- has to be special-cased because the implicit operator does not have
1349 -- a symmetric signature, and may not be hidden by the explicit one.
1351 elsif (Nkind (N) = N_Function_Call
1352 and then Nkind (Name (N)) = N_Expanded_Name
1353 and then (Chars (Predef_Subp) /= Name_Op_Expon
1354 or else Hides_Op (User_Subp, Predef_Subp))
1355 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1356 or else Hides_Op (User_Subp, Predef_Subp)
1358 if It1.Nam = User_Subp then
1364 -- Otherwise, the predefined operator has precedence, or if the
1365 -- user-defined operation is directly visible we have a true ambiguity.
1366 -- If this is a fixed-point multiplication and division in Ada83 mode,
1367 -- exclude the universal_fixed operator, which often causes ambiguities
1371 if (In_Open_Scopes (Scope (User_Subp))
1372 or else Is_Potentially_Use_Visible (User_Subp))
1373 and then not In_Instance
1375 if Is_Fixed_Point_Type (Typ)
1376 and then (Chars (Nam1) = Name_Op_Multiply
1377 or else Chars (Nam1) = Name_Op_Divide)
1380 if It2.Nam = Predef_Subp then
1390 elsif It1.Nam = Predef_Subp then
1400 ---------------------
1401 -- End_Interp_List --
1402 ---------------------
1404 procedure End_Interp_List is
1406 All_Interp.Table (All_Interp.Last) := No_Interp;
1407 All_Interp.Increment_Last;
1408 end End_Interp_List;
1410 -------------------------
1411 -- Entity_Matches_Spec --
1412 -------------------------
1414 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1416 -- Simple case: same entity kinds, type conformance is required.
1417 -- A parameterless function can also rename a literal.
1419 if Ekind (Old_S) = Ekind (New_S)
1420 or else (Ekind (New_S) = E_Function
1421 and then Ekind (Old_S) = E_Enumeration_Literal)
1423 return Type_Conformant (New_S, Old_S);
1425 elsif Ekind (New_S) = E_Function
1426 and then Ekind (Old_S) = E_Operator
1428 return Operator_Matches_Spec (Old_S, New_S);
1430 elsif Ekind (New_S) = E_Procedure
1431 and then Is_Entry (Old_S)
1433 return Type_Conformant (New_S, Old_S);
1438 end Entity_Matches_Spec;
1440 ----------------------
1441 -- Find_Unique_Type --
1442 ----------------------
1444 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1445 T : constant Entity_Id := Etype (L);
1448 TR : Entity_Id := Any_Type;
1451 if Is_Overloaded (R) then
1452 Get_First_Interp (R, I, It);
1454 while Present (It.Typ) loop
1455 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1457 -- If several interpretations are possible and L is universal,
1458 -- apply preference rule.
1460 if TR /= Any_Type then
1462 if (T = Universal_Integer or else T = Universal_Real)
1473 Get_Next_Interp (I, It);
1478 -- In the non-overloaded case, the Etype of R is already set
1485 -- If one of the operands is Universal_Fixed, the type of the
1486 -- other operand provides the context.
1488 if Etype (R) = Universal_Fixed then
1491 elsif T = Universal_Fixed then
1494 -- Ada 0Y (AI-230): Support the following operators:
1496 -- function "=" (L, R : universal_access) return Boolean;
1497 -- function "/=" (L, R : universal_access) return Boolean;
1499 elsif Extensions_Allowed
1500 and then Ekind (Etype (L)) = E_Anonymous_Access_Type
1501 and then Is_Access_Type (Etype (R))
1505 elsif Extensions_Allowed
1506 and then Ekind (Etype (R)) = E_Anonymous_Access_Type
1507 and then Is_Access_Type (Etype (L))
1512 return Specific_Type (T, Etype (R));
1515 end Find_Unique_Type;
1517 ----------------------
1518 -- Get_First_Interp --
1519 ----------------------
1521 procedure Get_First_Interp
1523 I : out Interp_Index;
1527 Int_Ind : Interp_Index;
1531 -- If a selected component is overloaded because the selector has
1532 -- multiple interpretations, the node is a call to a protected
1533 -- operation or an indirect call. Retrieve the interpretation from
1534 -- the selector name. The selected component may be overloaded as well
1535 -- if the prefix is overloaded. That case is unchanged.
1537 if Nkind (N) = N_Selected_Component
1538 and then Is_Overloaded (Selector_Name (N))
1540 O_N := Selector_Name (N);
1545 Map_Ptr := Headers (Hash (O_N));
1547 while Present (Interp_Map.Table (Map_Ptr).Node) loop
1548 if Interp_Map.Table (Map_Ptr).Node = O_N then
1549 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
1550 It := All_Interp.Table (Int_Ind);
1554 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
1558 -- Procedure should never be called if the node has no interpretations
1560 raise Program_Error;
1561 end Get_First_Interp;
1563 ----------------------
1564 -- Get_Next_Interp --
1565 ----------------------
1567 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
1570 It := All_Interp.Table (I);
1571 end Get_Next_Interp;
1573 -------------------------
1574 -- Has_Compatible_Type --
1575 -------------------------
1577 function Has_Compatible_Type
1590 if Nkind (N) = N_Subtype_Indication
1591 or else not Is_Overloaded (N)
1594 Covers (Typ, Etype (N))
1596 (not Is_Tagged_Type (Typ)
1597 and then Ekind (Typ) /= E_Anonymous_Access_Type
1598 and then Covers (Etype (N), Typ));
1601 Get_First_Interp (N, I, It);
1603 while Present (It.Typ) loop
1604 if (Covers (Typ, It.Typ)
1606 (Scope (It.Nam) /= Standard_Standard
1607 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
1609 or else (not Is_Tagged_Type (Typ)
1610 and then Ekind (Typ) /= E_Anonymous_Access_Type
1611 and then Covers (It.Typ, Typ))
1616 Get_Next_Interp (I, It);
1621 end Has_Compatible_Type;
1627 function Hash (N : Node_Id) return Int is
1629 -- Nodes have a size that is power of two, so to select significant
1630 -- bits only we remove the low-order bits.
1632 return ((Int (N) / 2 ** 5) mod Header_Size);
1639 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
1640 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
1643 return Operator_Matches_Spec (Op, F)
1644 and then (In_Open_Scopes (Scope (F))
1645 or else Scope (F) = Scope (Btyp)
1646 or else (not In_Open_Scopes (Scope (Btyp))
1647 and then not In_Use (Btyp)
1648 and then not In_Use (Scope (Btyp))));
1651 ------------------------
1652 -- Init_Interp_Tables --
1653 ------------------------
1655 procedure Init_Interp_Tables is
1659 Headers := (others => No_Entry);
1660 end Init_Interp_Tables;
1662 ---------------------
1663 -- Intersect_Types --
1664 ---------------------
1666 function Intersect_Types (L, R : Node_Id) return Entity_Id is
1667 Index : Interp_Index;
1671 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
1672 -- Find interpretation of right arg that has type compatible with T
1674 --------------------------
1675 -- Check_Right_Argument --
1676 --------------------------
1678 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
1679 Index : Interp_Index;
1684 if not Is_Overloaded (R) then
1685 return Specific_Type (T, Etype (R));
1688 Get_First_Interp (R, Index, It);
1691 T2 := Specific_Type (T, It.Typ);
1693 if T2 /= Any_Type then
1697 Get_Next_Interp (Index, It);
1698 exit when No (It.Typ);
1703 end Check_Right_Argument;
1705 -- Start processing for Intersect_Types
1708 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
1712 if not Is_Overloaded (L) then
1713 Typ := Check_Right_Argument (Etype (L));
1717 Get_First_Interp (L, Index, It);
1719 while Present (It.Typ) loop
1720 Typ := Check_Right_Argument (It.Typ);
1721 exit when Typ /= Any_Type;
1722 Get_Next_Interp (Index, It);
1727 -- If Typ is Any_Type, it means no compatible pair of types was found
1729 if Typ = Any_Type then
1731 if Nkind (Parent (L)) in N_Op then
1732 Error_Msg_N ("incompatible types for operator", Parent (L));
1734 elsif Nkind (Parent (L)) = N_Range then
1735 Error_Msg_N ("incompatible types given in constraint", Parent (L));
1738 Error_Msg_N ("incompatible types", Parent (L));
1743 end Intersect_Types;
1749 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
1753 if Base_Type (T1) = Base_Type (T2) then
1756 elsif Is_Private_Type (T1)
1757 and then Present (Full_View (T1))
1758 and then Base_Type (T2) = Base_Type (Full_View (T1))
1766 -- If there was a error on the type declaration, do not recurse
1768 if Error_Posted (Par) then
1771 elsif Base_Type (T1) = Base_Type (Par)
1772 or else (Is_Private_Type (T1)
1773 and then Present (Full_View (T1))
1774 and then Base_Type (Par) = Base_Type (Full_View (T1)))
1778 elsif Is_Private_Type (Par)
1779 and then Present (Full_View (Par))
1780 and then Full_View (Par) = Base_Type (T1)
1784 elsif Etype (Par) /= Par then
1793 ---------------------------
1794 -- Is_Invisible_Operator --
1795 ---------------------------
1797 function Is_Invisible_Operator
1802 Orig_Node : constant Node_Id := Original_Node (N);
1805 if Nkind (N) not in N_Op then
1808 elsif not Comes_From_Source (N) then
1811 elsif No (Universal_Interpretation (Right_Opnd (N))) then
1814 elsif Nkind (N) in N_Binary_Op
1815 and then No (Universal_Interpretation (Left_Opnd (N)))
1821 and then not In_Open_Scopes (Scope (T))
1822 and then not Is_Potentially_Use_Visible (T)
1823 and then not In_Use (T)
1824 and then not In_Use (Scope (T))
1826 (Nkind (Orig_Node) /= N_Function_Call
1827 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
1828 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
1830 and then not In_Instance;
1832 end Is_Invisible_Operator;
1838 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
1842 S := Ancestor_Subtype (T1);
1843 while Present (S) loop
1847 S := Ancestor_Subtype (S);
1858 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
1859 Index : Interp_Index;
1863 Get_First_Interp (Nam, Index, It);
1864 while Present (It.Nam) loop
1865 if Scope (It.Nam) = Standard_Standard
1866 and then Scope (It.Typ) /= Standard_Standard
1868 Error_Msg_Sloc := Sloc (Parent (It.Typ));
1869 Error_Msg_NE (" & (inherited) declared#!", Err, It.Nam);
1872 Error_Msg_Sloc := Sloc (It.Nam);
1873 Error_Msg_NE (" & declared#!", Err, It.Nam);
1876 Get_Next_Interp (Index, It);
1884 procedure New_Interps (N : Node_Id) is
1888 All_Interp.Increment_Last;
1889 All_Interp.Table (All_Interp.Last) := No_Interp;
1891 Map_Ptr := Headers (Hash (N));
1893 if Map_Ptr = No_Entry then
1895 -- Place new node at end of table
1897 Interp_Map.Increment_Last;
1898 Headers (Hash (N)) := Interp_Map.Last;
1901 -- Place node at end of chain, or locate its previous entry.
1904 if Interp_Map.Table (Map_Ptr).Node = N then
1906 -- Node is already in the table, and is being rewritten.
1907 -- Start a new interp section, retain hash link.
1909 Interp_Map.Table (Map_Ptr).Node := N;
1910 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
1911 Set_Is_Overloaded (N, True);
1915 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
1916 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
1920 -- Chain the new node.
1922 Interp_Map.Increment_Last;
1923 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
1926 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
1927 Set_Is_Overloaded (N, True);
1930 ---------------------------
1931 -- Operator_Matches_Spec --
1932 ---------------------------
1934 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
1935 Op_Name : constant Name_Id := Chars (Op);
1936 T : constant Entity_Id := Etype (New_S);
1944 -- To verify that a predefined operator matches a given signature,
1945 -- do a case analysis of the operator classes. Function can have one
1946 -- or two formals and must have the proper result type.
1948 New_F := First_Formal (New_S);
1949 Old_F := First_Formal (Op);
1952 while Present (New_F) and then Present (Old_F) loop
1954 Next_Formal (New_F);
1955 Next_Formal (Old_F);
1958 -- Definite mismatch if different number of parameters
1960 if Present (Old_F) or else Present (New_F) then
1966 T1 := Etype (First_Formal (New_S));
1968 if Op_Name = Name_Op_Subtract
1969 or else Op_Name = Name_Op_Add
1970 or else Op_Name = Name_Op_Abs
1972 return Base_Type (T1) = Base_Type (T)
1973 and then Is_Numeric_Type (T);
1975 elsif Op_Name = Name_Op_Not then
1976 return Base_Type (T1) = Base_Type (T)
1977 and then Valid_Boolean_Arg (Base_Type (T));
1986 T1 := Etype (First_Formal (New_S));
1987 T2 := Etype (Next_Formal (First_Formal (New_S)));
1989 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
1990 or else Op_Name = Name_Op_Xor
1992 return Base_Type (T1) = Base_Type (T2)
1993 and then Base_Type (T1) = Base_Type (T)
1994 and then Valid_Boolean_Arg (Base_Type (T));
1996 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
1997 return Base_Type (T1) = Base_Type (T2)
1998 and then not Is_Limited_Type (T1)
1999 and then Is_Boolean_Type (T);
2001 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2002 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2004 return Base_Type (T1) = Base_Type (T2)
2005 and then Valid_Comparison_Arg (T1)
2006 and then Is_Boolean_Type (T);
2008 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2009 return Base_Type (T1) = Base_Type (T2)
2010 and then Base_Type (T1) = Base_Type (T)
2011 and then Is_Numeric_Type (T);
2013 -- for division and multiplication, a user-defined function does
2014 -- not match the predefined universal_fixed operation, except in
2017 elsif Op_Name = Name_Op_Divide then
2018 return (Base_Type (T1) = Base_Type (T2)
2019 and then Base_Type (T1) = Base_Type (T)
2020 and then Is_Numeric_Type (T)
2021 and then (not Is_Fixed_Point_Type (T)
2024 -- Mixed_Mode operations on fixed-point types.
2026 or else (Base_Type (T1) = Base_Type (T)
2027 and then Base_Type (T2) = Base_Type (Standard_Integer)
2028 and then Is_Fixed_Point_Type (T))
2030 -- A user defined operator can also match (and hide) a mixed
2031 -- operation on universal literals.
2033 or else (Is_Integer_Type (T2)
2034 and then Is_Floating_Point_Type (T1)
2035 and then Base_Type (T1) = Base_Type (T));
2037 elsif Op_Name = Name_Op_Multiply then
2038 return (Base_Type (T1) = Base_Type (T2)
2039 and then Base_Type (T1) = Base_Type (T)
2040 and then Is_Numeric_Type (T)
2041 and then (not Is_Fixed_Point_Type (T)
2044 -- Mixed_Mode operations on fixed-point types.
2046 or else (Base_Type (T1) = Base_Type (T)
2047 and then Base_Type (T2) = Base_Type (Standard_Integer)
2048 and then Is_Fixed_Point_Type (T))
2050 or else (Base_Type (T2) = Base_Type (T)
2051 and then Base_Type (T1) = Base_Type (Standard_Integer)
2052 and then Is_Fixed_Point_Type (T))
2054 or else (Is_Integer_Type (T2)
2055 and then Is_Floating_Point_Type (T1)
2056 and then Base_Type (T1) = Base_Type (T))
2058 or else (Is_Integer_Type (T1)
2059 and then Is_Floating_Point_Type (T2)
2060 and then Base_Type (T2) = Base_Type (T));
2062 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2063 return Base_Type (T1) = Base_Type (T2)
2064 and then Base_Type (T1) = Base_Type (T)
2065 and then Is_Integer_Type (T);
2067 elsif Op_Name = Name_Op_Expon then
2068 return Base_Type (T1) = Base_Type (T)
2069 and then Is_Numeric_Type (T)
2070 and then Base_Type (T2) = Base_Type (Standard_Integer);
2072 elsif Op_Name = Name_Op_Concat then
2073 return Is_Array_Type (T)
2074 and then (Base_Type (T) = Base_Type (Etype (Op)))
2075 and then (Base_Type (T1) = Base_Type (T)
2077 Base_Type (T1) = Base_Type (Component_Type (T)))
2078 and then (Base_Type (T2) = Base_Type (T)
2080 Base_Type (T2) = Base_Type (Component_Type (T)));
2086 end Operator_Matches_Spec;
2092 procedure Remove_Interp (I : in out Interp_Index) is
2096 -- Find end of Interp list and copy downward to erase the discarded one
2100 while Present (All_Interp.Table (II).Typ) loop
2104 for J in I + 1 .. II loop
2105 All_Interp.Table (J - 1) := All_Interp.Table (J);
2108 -- Back up interp. index to insure that iterator will pick up next
2109 -- available interpretation.
2118 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2120 O_N : Node_Id := Old_N;
2123 if Is_Overloaded (Old_N) then
2124 if Nkind (Old_N) = N_Selected_Component
2125 and then Is_Overloaded (Selector_Name (Old_N))
2127 O_N := Selector_Name (Old_N);
2130 Map_Ptr := Headers (Hash (O_N));
2132 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2133 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2134 pragma Assert (Map_Ptr /= No_Entry);
2137 New_Interps (New_N);
2138 Interp_Map.Table (Interp_Map.Last).Index :=
2139 Interp_Map.Table (Map_Ptr).Index;
2147 function Specific_Type (T1, T2 : Entity_Id) return Entity_Id is
2148 B1 : constant Entity_Id := Base_Type (T1);
2149 B2 : constant Entity_Id := Base_Type (T2);
2151 function Is_Remote_Access (T : Entity_Id) return Boolean;
2152 -- Check whether T is the equivalent type of a remote access type.
2153 -- If distribution is enabled, T is a legal context for Null.
2155 ----------------------
2156 -- Is_Remote_Access --
2157 ----------------------
2159 function Is_Remote_Access (T : Entity_Id) return Boolean is
2161 return Is_Record_Type (T)
2162 and then (Is_Remote_Call_Interface (T)
2163 or else Is_Remote_Types (T))
2164 and then Present (Corresponding_Remote_Type (T))
2165 and then Is_Access_Type (Corresponding_Remote_Type (T));
2166 end Is_Remote_Access;
2168 -- Start of processing for Specific_Type
2171 if T1 = Any_Type or else T2 = Any_Type then
2179 or else (T1 = Universal_Integer and then Is_Integer_Type (T2))
2180 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2181 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2182 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2187 or else (T2 = Universal_Integer and then Is_Integer_Type (T1))
2188 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2189 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2190 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2194 elsif T2 = Any_String and then Is_String_Type (T1) then
2197 elsif T1 = Any_String and then Is_String_Type (T2) then
2200 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2203 elsif T1 = Any_Character and then Is_Character_Type (T2) then
2206 elsif T1 = Any_Access
2207 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
2211 elsif T2 = Any_Access
2212 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
2216 elsif T2 = Any_Composite
2217 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
2221 elsif T1 = Any_Composite
2222 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
2226 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
2229 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
2232 -- Special cases for equality operators (all other predefined
2233 -- operators can never apply to tagged types)
2235 elsif Is_Class_Wide_Type (T1)
2236 and then Is_Ancestor (Root_Type (T1), T2)
2240 elsif Is_Class_Wide_Type (T2)
2241 and then Is_Ancestor (Root_Type (T2), T1)
2245 elsif (Ekind (B1) = E_Access_Subprogram_Type
2247 Ekind (B1) = E_Access_Protected_Subprogram_Type)
2248 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
2249 and then Is_Access_Type (T2)
2253 elsif (Ekind (B2) = E_Access_Subprogram_Type
2255 Ekind (B2) = E_Access_Protected_Subprogram_Type)
2256 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
2257 and then Is_Access_Type (T1)
2261 elsif (Ekind (T1) = E_Allocator_Type
2262 or else Ekind (T1) = E_Access_Attribute_Type
2263 or else Ekind (T1) = E_Anonymous_Access_Type)
2264 and then Is_Access_Type (T2)
2268 elsif (Ekind (T2) = E_Allocator_Type
2269 or else Ekind (T2) = E_Access_Attribute_Type
2270 or else Ekind (T2) = E_Anonymous_Access_Type)
2271 and then Is_Access_Type (T1)
2275 -- If none of the above cases applies, types are not compatible.
2282 -----------------------
2283 -- Valid_Boolean_Arg --
2284 -----------------------
2286 -- In addition to booleans and arrays of booleans, we must include
2287 -- aggregates as valid boolean arguments, because in the first pass
2288 -- of resolution their components are not examined. If it turns out not
2289 -- to be an aggregate of booleans, this will be diagnosed in Resolve.
2290 -- Any_Composite must be checked for prior to the array type checks
2291 -- because Any_Composite does not have any associated indexes.
2293 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
2295 return Is_Boolean_Type (T)
2296 or else T = Any_Composite
2297 or else (Is_Array_Type (T)
2298 and then T /= Any_String
2299 and then Number_Dimensions (T) = 1
2300 and then Is_Boolean_Type (Component_Type (T))
2301 and then (not Is_Private_Composite (T)
2302 or else In_Instance)
2303 and then (not Is_Limited_Composite (T)
2304 or else In_Instance))
2305 or else Is_Modular_Integer_Type (T)
2306 or else T = Universal_Integer;
2307 end Valid_Boolean_Arg;
2309 --------------------------
2310 -- Valid_Comparison_Arg --
2311 --------------------------
2313 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
2316 if T = Any_Composite then
2318 elsif Is_Discrete_Type (T)
2319 or else Is_Real_Type (T)
2322 elsif Is_Array_Type (T)
2323 and then Number_Dimensions (T) = 1
2324 and then Is_Discrete_Type (Component_Type (T))
2325 and then (not Is_Private_Composite (T)
2326 or else In_Instance)
2327 and then (not Is_Limited_Composite (T)
2328 or else In_Instance)
2331 elsif Is_String_Type (T) then
2336 end Valid_Comparison_Arg;
2338 ---------------------
2339 -- Write_Overloads --
2340 ---------------------
2342 procedure Write_Overloads (N : Node_Id) is
2348 if not Is_Overloaded (N) then
2349 Write_Str ("Non-overloaded entity ");
2351 Write_Entity_Info (Entity (N), " ");
2354 Get_First_Interp (N, I, It);
2355 Write_Str ("Overloaded entity ");
2359 while Present (Nam) loop
2360 Write_Entity_Info (Nam, " ");
2361 Write_Str ("=================");
2363 Get_Next_Interp (I, It);
2367 end Write_Overloads;
2369 -----------------------
2370 -- Write_Interp_Ref --
2371 -----------------------
2373 procedure Write_Interp_Ref (Map_Ptr : Int) is
2375 Write_Str (" Node: ");
2376 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
2377 Write_Str (" Index: ");
2378 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
2379 Write_Str (" Next: ");
2380 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
2382 end Write_Interp_Ref;