| blob | 658f9eb2b7243676cf095e6e5cd400eac17d3717 |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2024, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
101 -----------------------
102 -- Local Subprograms --
103 -----------------------
105 -- Second pass (top-down) type checking and overload resolution procedures
106 -- Typ is the type required by context. These procedures propagate the
107 -- type information recursively to the descendants of N. If the node is not
108 -- overloaded, its Etype is established in the first pass. If overloaded,
109 -- the Resolve routines set the correct type. For arithmetic operators, the
110 -- Etype is the base type of the context.
112 -- Note that Resolve_Attribute is separated off in Sem_Attr
114 function Has_Applicable_User_Defined_Literal
117 -- Check whether N is a literal or a named number, and whether Typ has a
118 -- user-defined literal aspect that may apply to N. In this case, replace
119 -- N with a call to the corresponding function and return True.
122 -- Enforce the restrictions on the use of discriminants when constraining
123 -- a component of a discriminated type (record or concurrent type).
126 -- Given a node for an operator associated with type T, check that the
127 -- operator is visible. Operators all of whose operands are universal must
128 -- be checked for visibility during resolution because their type is not
129 -- determinable based on their operands.
131 procedure Check_Fully_Declared_Prefix
134 -- Check that the type of the prefix of a dereference is not incomplete
137 -- Given a call node, Call, which is known to occur immediately within the
138 -- subprogram being called, determines whether it is a detectable case of
139 -- an infinite recursion, and if so, outputs appropriate messages. Returns
140 -- True if an infinite recursion is detected, and False otherwise.
143 -- N is the node for a logical operator. If the operator is predefined, and
144 -- the root type of the operands is Standard.Boolean, then a check is made
145 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
146 -- the style check for Style_Check_Boolean_And_Or.
149 -- N is either an indexed component or a selected component. Return true
150 -- if the prefix denotes an Atomic but not Volatile_Full_Access object that
151 -- has an address clause (the case in which we may want to give a warning).
154 -- Determine whether E is an access type declared by an access declaration,
155 -- and not an (anonymous) allocator type.
158 -- Utility to check whether the entity for an operator is a predefined
159 -- operator, in which case the expression is left as an operator in the
160 -- tree (else it is rewritten into a call). An instance of an intrinsic
161 -- conversion operation may be given an operator name, but is not treated
162 -- like an operator. Note that an operator that is an imported back-end
163 -- builtin has convention Intrinsic, but is expected to be rewritten into
164 -- a call, so such an operator is not treated as predefined by this
165 -- predicate.
167 function Original_Implementation_Base_Type
169 -- Like Implementation_Base_Type, but looks at Original_Node.
171 procedure Preanalyze_And_Resolve
175 -- Subsidiary of public versions of Preanalyze_And_Resolve.
178 -- If a default expression in entry call N depends on the discriminants
179 -- of the task, it must be replaced with a reference to the discriminant
180 -- of the task being called.
182 procedure Resolve_Dependent_Expression
186 -- Internal procedure to resolve the dependent expression Expr of the
187 -- conditional expression N with type Typ.
189 procedure Resolve_Op_Concat_Arg
194 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
195 -- concatenation operator. The operand is either of the array type or of
196 -- the component type. If the operand is an aggregate, and the component
197 -- type is composite, this is ambiguous if component type has aggregates.
200 -- Does the first part of the work of Resolve_Op_Concat
203 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
204 -- has been resolved. See Resolve_Op_Concat for details.
222 procedure Resolve_Interpolated_String_Literal
248 function Operator_Kind
251 -- Utility to map the name of an operator into the corresponding Node. Used
252 -- by other node rewriting procedures.
255 -- Resolve actuals of call, and add default expressions for missing ones.
256 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
257 -- called subprogram.
260 -- Called from Resolve_Call, when the prefix denotes an entry or element
261 -- of entry family. Actuals are resolved as for subprograms, and the node
262 -- is rebuilt as an entry call. Also called for protected operations. Typ
263 -- is the context type, which is used when the operation is a protected
264 -- function with no arguments, and the return value is indexed.
267 -- Called when P is the prefix of an indexed component, or of a selected
268 -- component, or of a slice. If P is of an access type, we unconditionally
269 -- rewrite it as an explicit dereference. This ensures that the expander
270 -- and the code generator have a fully explicit tree to work with.
273 -- A call to a user-defined intrinsic operator is rewritten as a call to
274 -- the corresponding predefined operator, with suitable conversions. Note
275 -- that this applies only for intrinsic operators that denote predefined
276 -- operators, not ones that are intrinsic imports of back-end builtins.
279 -- Ditto, for arithmetic unary operators
282 -- If an operator node resolves to a call to a user-defined operator,
283 -- rewrite the node as a function call.
285 procedure Make_Call_Into_Operator
289 -- Inverse transformation: if an operator is given in functional notation,
290 -- then after resolving the node, transform into an operator node, so that
291 -- operands are resolved properly. Recall that predefined operators do not
292 -- have a full signature and special resolution rules apply.
294 procedure Rewrite_Renamed_Operator
298 -- An operator can rename another, e.g. in an instantiation. In that
299 -- case, the proper operator node must be constructed and resolved.
302 -- The String_Literal_Subtype is built for all strings that are not
303 -- operands of a static concatenation operation. It is also built for
304 -- expressions generated by the expansion of the External_Initialization
305 -- aspect. If the argument is not an N_String_Literal node or an
306 -- N_External_Initializer node, then the call has no effect.
309 -- Build subtype of array type, with the range specified by the slice
312 -- Called after N has been resolved and evaluated, but before range checks
313 -- have been applied. This rewrites the conversion into a simpler form.
315 function Try_User_Defined_Literal
318 -- If the node is a literal or a named number or a conditional expression
319 -- whose dependent expressions are all literals or named numbers, and the
320 -- context type has a user-defined literal aspect, then rewrite the node
321 -- or its leaf nodes as calls to the corresponding function, which plays
322 -- the role of an implicit conversion.
324 function Try_User_Defined_Literal_For_Operator
327 -- If an operator node has a literal operand, check whether the type of the
328 -- context, or that of the other operand has a user-defined literal aspect
329 -- that can be applied to the literal to resolve the node. If such aspect
330 -- exists, replace literal with a call to the corresponding function and
331 -- return True, return false otherwise.
334 -- A universal_fixed expression in an universal context is unambiguous if
335 -- there is only one applicable fixed point type. Determining whether there
336 -- is only one requires a search over all visible entities, and happens
337 -- only in very pathological cases (see 6115-006).
339 -------------------------
340 -- Ambiguous_Character --
341 -------------------------
346 begin
350 -- First the ones in Standard
355 -- Include Wide_Wide_Character in Ada 2005 mode
361 -- Now any other types that match
371 -------------------------
372 -- Analyze_And_Resolve --
373 -------------------------
376 begin
382 begin
387 -- Versions with check(s) suppressed
389 procedure Analyze_And_Resolve
393 is
396 begin
398 declare
400 begin
406 else
407 declare
409 begin
417 and then Scope_Is_Transient
418 then
419 -- This can only happen if a transient scope was created for an inner
420 -- expression, which will be removed upon completion of the analysis
421 -- of an enclosing construct. The transient scope must have the
422 -- suppress status of the enclosing environment, not of this Analyze
423 -- call.
426 Scope_Suppress;
430 procedure Analyze_And_Resolve
433 is
436 begin
438 declare
440 begin
446 else
447 declare
449 begin
458 Scope_Suppress;
462 -------------------------------------
463 -- Has_Applicable_User_Defined_Literal --
464 -------------------------------------
466 function Has_Applicable_User_Defined_Literal
469 is
471 Literal_Aspect_Map :
492 begin
494 | N_Interpolated_String_Literal
495 and then Present
497 or else
500 and then
501 Present
502 (Find_Aspect
504 then
505 Lit_Aspect :=
509 Callee :=
515 then
516 Callee :=
517 Corresponding_Primitive_Op
522 -- Handle an identifier that denotes a named number.
529 Start_String;
530 Store_String_Chars
535 else
537 Start_String;
543 Store_String_Chars
547 -- Note: Set_Etype is called below on Param1
550 Start_String;
551 Store_String_Chars
560 else
561 Error_Msg_NE
575 else
576 Param1 :=
577 Make_String_Literal
582 Call :=
583 Make_Function_Call
593 else
599 -- Conversion not needed if the result type of the call is class-wide
600 -- or if the result type matches the context type.
604 then
605 -- Conversion may be needed in case of an inherited
606 -- aspect of a derived type. For a null extension, we
607 -- use a null extension aggregate instead because the
608 -- downward type conversion would be illegal.
610 if Is_Null_Extension_Of
613 then
617 else
627 else
632 ----------------------------
633 -- Check_Discriminant_Use --
634 ----------------------------
642 begin
643 -- Any use in a spec-expression is legal
650 -- Discriminant cannot be used to constrain a scalar type
657 then
662 -- The following check catches the unusual case where a
663 -- discriminant appears within an index constraint that is part
664 -- of a larger expression within a constraint on a component,
665 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
666 -- check case of record components, and note that a similar check
667 -- should also apply in the case of discriminant constraints
668 -- below. ???
670 -- Note that the check for N_Subtype_Declaration below is to
671 -- detect the valid use of discriminants in the constraints of a
672 -- subtype declaration when this subtype declaration appears
673 -- inside the scope of a record type (which is syntactically
674 -- illegal, but which may be created as part of derived type
675 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
676 -- for more info.
680 and then not
682 and then
684 | N_Subtype_Declaration
686 then
687 Error_Msg_N
692 -- Detect a common error:
694 -- type R (D : Positive := 100) is record
695 -- Name : String (1 .. D);
696 -- end record;
698 -- The default value causes an object of type R to be allocated
699 -- with room for Positive'Last characters. The RM does not mandate
700 -- the allocation of the maximum size, but that is what GNAT does
701 -- so we should warn the programmer that there is a problem.
710 -- Return True if type T has a large enough range that any
711 -- array whose index type covered the whole range of the type
712 -- would likely raise Storage_Error.
714 ------------------------
715 -- Large_Storage_Type --
716 ------------------------
719 begin
720 -- The type is considered large if its bounds are known at
721 -- compile time and if it requires at least as many bits as
722 -- a Positive to store the possible values.
726 and then
731 -- Start of processing for Check_Large
733 begin
734 -- Check that the Disc has a large range
740 -- If the enclosing type is limited, we allocate only the
741 -- default value, not the maximum, and there is no need for
742 -- a warning.
748 -- Check that it is the high bound
752 then
756 -- Check the array allows a large range at this bound. First
757 -- find the array
771 -- Next, find the dimension
779 loop
788 -- Now, check the dimension has a large range
794 -- Warn about the danger
796 Error_Msg_N
806 -- Legal case is in index or discriminant constraint
809 | N_Discriminant_Association
810 then
812 Error_Msg_N
817 then
818 Error_Msg_N
824 -- Otherwise, context is an expression. It should not be within (i.e. a
825 -- subexpression of) a constraint for a component.
827 else
831 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
832 loop
838 -- If the discriminant is used in an expression that is a bound of a
839 -- scalar type, an Itype is created and the bounds are attached to
840 -- its range, not to the original subtype indication. Such use is of
841 -- course a double fault.
845 | N_Derived_Type_Definition
848 -- The constraint itself may be given by a subtype indication,
849 -- rather than by a more common discrete range.
852 and then
856 then
857 Error_Msg_N
863 --------------------------------
864 -- Check_For_Visible_Operator --
865 --------------------------------
868 begin
872 then
873 Error_Msg_NE -- CODEFIX
875 Error_Msg_N -- CODEFIX
880 ---------------------------------
881 -- Check_Fully_Declared_Prefix --
882 ---------------------------------
884 procedure Check_Fully_Declared_Prefix
887 is
888 begin
889 -- Check that the designated type of the prefix of a dereference is
890 -- not an incomplete type. This cannot be done unconditionally, because
891 -- dereferences of private types are legal in default expressions. This
892 -- case is taken care of in Check_Fully_Declared, called below. There
893 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
895 -- This consideration also applies to similar checks for allocators,
896 -- qualified expressions, and type conversions.
898 -- An additional exception concerns other per-object expressions that
899 -- are not directly related to component declarations, in particular
900 -- representation pragmas for tasks. These will be per-object
901 -- expressions if they depend on discriminants or some global entity.
902 -- If the task has access discriminants, the designated type may be
903 -- incomplete at the point the expression is resolved. This resolution
904 -- takes place within the body of the initialization procedure, where
905 -- the discriminant is replaced by its discriminal.
909 then
912 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
913 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
914 -- Analyze_Object_Renaming, and Freeze_Entity.
920 E_Incomplete_Type
922 then
924 else
929 ------------------------------
930 -- Check_Infinite_Recursion --
931 ------------------------------
935 -- Determine whether call N invokes the related enclosing subprogram
936 -- with actuals that differ from the subprogram's formals.
939 -- Determine whether arbitrary node N denotes a conditional construct
942 -- Determine whether arbitrary node N denotes a control flow statement
943 -- or a construct that may contains such a statement.
946 -- Determine whether arbitrary node N appears immediately within the
947 -- statements of an entry or subprogram body.
950 -- Determine whether arbitrary node N appears immediately within the
951 -- body of an entry or subprogram, and is preceded by a single raise
952 -- statement.
955 -- Determine whether arbitrary node N denotes a raise statement
958 -- Determine whether arbitrary node N is the sole source statement in
959 -- the body of the enclosing subprogram.
962 -- Determine whether arbitrary node N is preceded by a control flow
963 -- statement.
966 -- Determine whether arbitrary node N appears within a conditional
967 -- construct.
969 --------------------------------------
970 -- Invoked_With_Different_Arguments --
971 --------------------------------------
979 begin
980 -- Determine whether the formals of the invoked subprogram are not
981 -- used as actuals in the call.
987 -- The current actual does not match the current formal
991 then
1002 ------------------------------
1003 -- Is_Conditional_Statement --
1004 ------------------------------
1007 begin
1008 return
1010 | N_Case_Expression
1011 | N_Case_Statement
1012 | N_If_Expression
1013 | N_If_Statement
1014 | N_Or_Else;
1017 -------------------------------
1018 -- Is_Control_Flow_Statement --
1019 -------------------------------
1022 begin
1023 -- It is assumed that all statements may affect the control flow in
1024 -- some way. A raise statement may be expanded into a non-statement
1025 -- node.
1030 --------------------------------
1031 -- Is_Immediately_Within_Body --
1032 --------------------------------
1037 begin
1038 return
1045 --------------------
1046 -- Is_Raise_Idiom --
1047 --------------------
1053 begin
1056 -- Assume that no raise statement has been seen yet
1060 -- Examine the statements preceding the input node, skipping
1061 -- internally-generated constructs.
1066 -- Multiple raise statements violate the idiom
1082 -- At this point the node must be preceded by a raise statement,
1083 -- and the raise statement has to be the sole statement within
1084 -- the enclosing entry or subprogram body.
1086 return
1093 ------------------------
1094 -- Is_Raise_Statement --
1095 ------------------------
1098 begin
1099 -- A raise statement may be transfomed into a Raise_xxx_Error node
1101 return
1106 -----------------------
1107 -- Is_Sole_Statement --
1108 -----------------------
1113 begin
1114 -- The input node appears within the statements of an entry or
1115 -- subprogram body. Examine the statements preceding the node.
1122 -- The statement is preceded by another statement or a source
1123 -- construct. This indicates that the node does not appear by
1124 -- itself.
1128 then
1138 -- The input node is within a construct nested inside the entry or
1139 -- subprogram body.
1144 ----------------------------------------
1145 -- Preceded_By_Control_Flow_Statement --
1146 ----------------------------------------
1148 function Preceded_By_Control_Flow_Statement
1150 is
1153 begin
1157 -- Examine the statements preceding the input node
1170 -- Assume that the node is part of some control flow statement
1175 ----------------------------------
1176 -- Within_Conditional_Statement --
1177 ----------------------------------
1182 begin
1188 -- Prevent the search from going too far
1200 -- Local variables
1205 -- Start of processing for Check_Infinite_Recursion
1207 begin
1208 -- The call is assumed to be safe when the enclosing subprogram is
1209 -- invoked with actuals other than its formals.
1210 --
1211 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1212 -- begin
1213 -- ...
1214 -- Proc (A1, A2, ..., AN);
1215 -- ...
1216 -- end Proc;
1221 -- The call is assumed to be safe when the invocation of the enclosing
1222 -- subprogram depends on a conditional statement.
1223 --
1224 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1225 -- begin
1226 -- ...
1227 -- if Some_Condition then
1228 -- Proc (F1, F2, ..., FN);
1229 -- end if;
1230 -- ...
1231 -- end Proc;
1236 -- The context of the call is assumed to be safe when the invocation of
1237 -- the enclosing subprogram is preceded by some control flow statement.
1238 --
1239 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1240 -- begin
1241 -- ...
1242 -- if Some_Condition then
1243 -- ...
1244 -- end if;
1245 -- ...
1246 -- Proc (F1, F2, ..., FN);
1247 -- ...
1248 -- end Proc;
1253 -- Detect an idiom where the context of the call is preceded by a single
1254 -- raise statement.
1255 --
1256 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1257 -- begin
1258 -- raise ...;
1259 -- Proc (F1, F2, ..., FN);
1260 -- end Proc;
1266 -- At this point it is certain that infinite recursion will take place
1267 -- as long as the call is executed. Detect a case where the context of
1268 -- the call is the sole source statement within the subprogram body.
1269 --
1270 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1271 -- begin
1272 -- Proc (F1, F2, ..., FN);
1273 -- end Proc;
1274 --
1275 -- Install an explicit raise to prevent the infinite recursion.
1286 -- Otherwise infinite recursion could take place, considering other flow
1287 -- control constructs such as gotos, exit statements, etc.
1289 else
1298 ---------------------------------------
1299 -- Check_No_Direct_Boolean_Operators --
1300 ---------------------------------------
1303 begin
1306 then
1307 -- Restriction only applies to original source code
1314 -- Do style check (but skip if in instance, error is on template)
1323 ------------------------------
1324 -- Check_Parameterless_Call --
1325 ------------------------------
1331 -- If the prefix is of an access_to_subprogram type, the node must be
1332 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1333 -- interpretations are access to subprograms.
1335 ---------------------------
1336 -- Prefix_Is_Access_Subp --
1337 ---------------------------
1343 begin
1344 -- If the context is an attribute reference that can apply to
1345 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1349 in Name_Address | Name_Code_Address | Name_Access
1350 then
1355 return
1358 else
1363 then
1374 -- Start of processing for Check_Parameterless_Call
1376 begin
1377 -- Defend against junk stuff if errors already detected
1384 then
1391 -- If the context expects a value, and the name is a procedure, this is
1392 -- most likely a missing 'Access. Don't try to resolve the parameterless
1393 -- call, error will be caught when the outer call is analyzed.
1398 and then
1400 | N_Function_Call
1401 | N_Procedure_Call_Statement
1402 then
1406 -- Rewrite as call if overloadable entity that is (or could be, in the
1407 -- overloaded case) a function call. If we know for sure that the entity
1408 -- is an enumeration literal, we do not rewrite it.
1410 -- If the entity is the name of an operator, it cannot be a call because
1411 -- operators cannot have default parameters. In this case, this must be
1412 -- a string whose contents coincide with an operator name. Set the kind
1413 -- of the node appropriately.
1421 -- Rewrite as call if it is an explicit dereference of an expression of
1422 -- a subprogram access type, and the subprogram type is not that of a
1423 -- procedure or entry.
1425 or else
1428 -- Rewrite as call if it is a selected component which is a function,
1429 -- this is the case of a call to a protected function (which may be
1430 -- overloaded with other protected operations).
1432 or else
1435 or else
1437 E_Entry | E_Procedure
1440 -- If one of the above three conditions is met, rewrite as call. Apply
1441 -- the rewriting only once.
1443 then
1446 then
1448 -- This may be a prefixed call that was not fully analyzed, e.g.
1449 -- an actual in an instance.
1454 then
1462 -- The node is the name of the parameterless call. Preserve its
1463 -- descendants, which may be complex expressions.
1467 -- If overloaded, overload set belongs to new copy
1471 -- Change node to parameterless function call (note that the
1472 -- Parameter_Associations associations field is left set to Empty,
1473 -- its normal default value since there are no parameters)
1493 ----------------------------------------
1494 -- Is_Atomic_Non_VFA_Ref_With_Address --
1495 ----------------------------------------
1501 -- Return true if E is Atomic but not Volatile_Full_Access
1503 -----------------------
1504 -- Is_Atomic_Non_VFA --
1505 -----------------------
1508 begin
1512 begin
1514 declare
1518 begin
1525 else
1530 -----------------------------
1531 -- Is_Definite_Access_Type --
1532 -----------------------------
1536 begin
1542 ----------------------
1543 -- Is_Predefined_Op --
1544 ----------------------
1547 begin
1548 -- Predefined operators are intrinsic subprograms
1554 -- A call to a back-end builtin is never a predefined operator
1565 -----------------------------
1566 -- Make_Call_Into_Operator --
1567 -----------------------------
1569 procedure Make_Call_Into_Operator
1573 is
1588 -- If the operand is not universal, and the operator is given by an
1589 -- expanded name, verify that the operand has an interpretation with a
1590 -- type defined in the given scope of the operator.
1593 -- Find a type of the given class in package Pack that contains the
1594 -- operator.
1596 ---------------------------
1597 -- Operand_Type_In_Scope --
1598 ---------------------------
1605 begin
1609 else
1623 ---------------
1624 -- Type_In_P --
1625 ---------------
1631 -- Verify that node is not part of the type declaration for the
1632 -- candidate type, which would otherwise be invisible.
1634 -------------
1635 -- In_Decl --
1636 -------------
1642 begin
1649 else
1654 loop
1657 else
1666 -- Start of processing for Type_In_P
1668 begin
1669 -- If the context type is declared in the prefix package, this is the
1670 -- desired base type.
1675 else
1689 -- Start of processing for Make_Call_Into_Operator
1691 begin
1694 -- Preserve the Comes_From_Source flag on the result if the original
1695 -- call came from source. Although it is not strictly the case that the
1696 -- operator as such comes from the source, logically it corresponds
1697 -- exactly to the function call in the source, so it should be marked
1698 -- this way (e.g. to make sure that validity checks work fine).
1702 -- Ensure that the corresponding operator has the same parent as the
1703 -- original call. This guarantees that parent traversals performed by
1704 -- the ABE mechanism succeed.
1708 -- Binary operator
1718 -- Unary operator
1720 else
1726 -- If the operator is denoted by an expanded name, and the prefix is
1727 -- not Standard, but the operator is a predefined one whose scope is
1728 -- Standard, then this is an implicit_operator, inserted as an
1729 -- interpretation by the procedure of the same name. This procedure
1730 -- overestimates the presence of implicit operators, because it does
1731 -- not examine the type of the operands. Verify now that the operand
1732 -- type appears in the given scope. If right operand is universal,
1733 -- check the other operand. In the case of concatenation, either
1734 -- argument can be the component type, so check the type of the result.
1735 -- If both arguments are literals, look for a type of the right kind
1736 -- defined in the given scope. This elaborate nonsense is brought to
1737 -- you courtesy of b33302a. The type itself must be frozen, so we must
1738 -- find the type of the proper class in the given scope.
1740 -- A final wrinkle is the multiplication operator for fixed point types,
1741 -- which is defined in Standard only, and not in the scope of the
1742 -- fixed point type itself.
1747 -- If this is a package renaming, get renamed entity, which will be
1748 -- the scope of the operands if operaton is type-correct.
1754 -- If the entity being called is defined in the given package, it is
1755 -- a renaming of a predefined operator, and known to be legal.
1759 then
1762 -- Visibility does not need to be checked in an instance: if the
1763 -- operator was not visible in the generic it has been diagnosed
1764 -- already, else there is an implicit copy of it in the instance.
1772 then
1777 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1778 -- available.
1784 then
1787 else
1796 and then Is_Binary
1798 then
1804 -- Verify that the scope contains a type that corresponds to
1805 -- the given literal. Optimize the case where Pack is Standard.
1826 else
1835 else
1844 then
1847 -- If the type is defined elsewhere, and the operator is not
1848 -- defined in the given scope (by a renaming declaration, e.g.)
1849 -- then this is an error as well. If an extension of System is
1850 -- present, and the type may be defined there, Pack must be
1851 -- System itself.
1858 then
1861 else
1867 then
1874 Error_Msg_NE
1879 -- Detect a mismatch between the context type and the result type
1880 -- in the named package, which is otherwise not detected if the
1881 -- operands are universal. Check is only needed if source entity is
1882 -- an operator, not a function that renames an operator.
1889 and then not In_Instance
1890 then
1893 then
1894 -- Already checked above
1898 -- Operator may be defined in an extension of System
1903 then
1906 else
1907 -- Could we use Wrong_Type here??? (this would require setting
1908 -- Etype (N) to the actual type found where Typ was expected).
1919 else
1923 -- If this is a call to a function that renames a predefined equality,
1924 -- the renaming declaration provides a type that must be used to
1925 -- resolve the operands. This must be done now because resolution of
1926 -- the equality node will not resolve any remaining ambiguity, and it
1927 -- assumes that the first operand is not overloaded.
1932 then
1942 -- If this is an arithmetic operator and the result type is private,
1943 -- the operands and the result must be wrapped in conversion to
1944 -- expose the underlying numeric type and expand the proper checks,
1945 -- e.g. on division.
1949 when N_Op_Add
1950 | N_Op_Divide
1951 | N_Op_Expon
1952 | N_Op_Mod
1953 | N_Op_Multiply
1954 | N_Op_Rem
1955 | N_Op_Subtract
1956 =>
1959 when N_Op_Abs
1960 | N_Op_Minus
1961 | N_Op_Plus
1962 =>
1968 else
1973 -------------------
1974 -- Operator_Kind --
1975 -------------------
1977 function Operator_Kind
1980 is
1983 begin
1984 -- Use CASE statement or array???
2021 else
2025 -- Unary operators
2027 else
2036 else
2044 ---------------------------------------
2045 -- Original_Implementation_Base_Type --
2046 ---------------------------------------
2048 function Original_Implementation_Base_Type
2050 is
2054 begin
2058 N_Full_Type_Declaration
2060 = N_Derived_Type_Definition
2061 then
2069 return Original_Implementation_Base_Type
2071 else
2076 ----------------------------
2077 -- Preanalyze_And_Resolve --
2078 ----------------------------
2080 procedure Preanalyze_And_Resolve
2084 is
2088 Inside_Preanalysis_Without_Freezing;
2089 begin
2094 Inside_Preanalysis_Without_Freezing :=
2101 -- See also Preanalyze_And_Resolve in sem.adb for similar handling
2103 -- Normally, we suppress all checks for this preanalysis. There is no
2104 -- point in processing them now, since they will be applied properly
2105 -- and in the proper location when the default expressions reanalyzed
2106 -- and reexpanded later on. We will also have more information at that
2107 -- point for possible suppression of individual checks.
2109 -- However, in GNATprove mode, most expansion is suppressed, and this
2110 -- later reanalysis and reexpansion may not occur. GNATprove mode does
2111 -- require the setting of checking flags for proof purposes, so we
2112 -- do the GNATprove preanalysis without suppressing checks.
2114 -- This special handling for SPARK mode is required for example in the
2115 -- case of Ada 2012 constructs such as quantified expressions, which are
2116 -- expanded in two separate steps.
2118 -- We also do not want to suppress checks if we are not dealing
2119 -- with a default expression. One such case that is known to reach
2120 -- this point is the expression of an expression function.
2124 else
2128 Expander_Mode_Restore;
2133 Inside_Preanalysis_Without_Freezing :=
2137 pragma Assert
2141 ----------------------------
2142 -- Preanalyze_And_Resolve --
2143 ----------------------------
2146 begin
2150 -- Version without context type
2155 begin
2162 Expander_Mode_Restore;
2166 ------------------------------------------
2167 -- Preanalyze_With_Freezing_And_Resolve --
2168 ------------------------------------------
2170 procedure Preanalyze_With_Freezing_And_Resolve
2173 is
2174 begin
2178 ----------------------------------
2179 -- Replace_Actual_Discriminants --
2180 ----------------------------------
2187 -- Comment needed???
2189 -------------------
2190 -- Process_Discr --
2191 -------------------
2196 begin
2202 then
2218 -- Start of processing for Replace_Actual_Discriminants
2220 begin
2224 -- Allow the replacement of concurrent discriminants in GNATprove even
2225 -- though this is a light expansion activity. Note that generic units
2226 -- are not modified.
2231 else
2247 -------------
2248 -- Resolve --
2249 -------------
2265 -- Determine whether a node comes from a predefined library unit or
2266 -- Standard.
2269 -- Try and fix up a literal so that it matches its expected type. New
2270 -- literals are manufactured if necessary to avoid cascaded errors.
2273 -- Additional diagnostics when an ambiguous call has an ambiguous
2274 -- argument (typically a controlling actual).
2277 -- Called when attempt at resolving current expression fails
2279 ------------------------------------
2280 -- Comes_From_Predefined_Lib_Unit --
2281 -------------------------------------
2284 begin
2285 return
2289 --------------------
2290 -- Patch_Up_Value --
2291 --------------------
2294 begin
2311 then
2316 Char_Literal_Value =>
2332 -------------------------------
2333 -- Report_Ambiguous_Argument --
2334 -------------------------------
2341 begin
2345 then
2348 -- Examine possible interpretations, and adapt the message
2349 -- for inherited subprograms declared by a type derivation.
2357 else
2365 -- Additional message and hint if the ambiguity involves an Ada 2022
2366 -- container aggregate.
2371 -----------------------
2372 -- Resolution_Failed --
2373 -----------------------
2376 begin
2379 -- Set the type to the desired one to minimize cascaded errors. Note
2380 -- that this is an approximation and does not work in all cases.
2387 -- The caller will return without calling the expander, so we need
2388 -- to set the analyzed flag. Note that it is fine to set Analyzed
2389 -- to True even if we are in the middle of a shallow analysis,
2390 -- (see the spec of sem for more details) since this is an error
2391 -- situation anyway, and there is no point in repeating the
2392 -- analysis later (indeed it won't work to repeat it later, since
2393 -- we haven't got a clear resolution of which entity is being
2394 -- referenced.)
2400 -- Start of processing for Resolve
2402 begin
2407 -- Access attribute on remote subprogram cannot be used for a non-remote
2408 -- access-to-subprogram type.
2412 | Name_Unrestricted_Access
2413 | Name_Unchecked_Access
2419 then
2420 Error_Msg_N
2424 -- If the context is a Remote_Access_To_Subprogram, access attributes
2425 -- must be resolved with the corresponding fat pointer. There is no need
2426 -- to check for the attribute name since the return type of an
2427 -- attribute is never a remote type.
2432 then
2433 declare
2441 begin
2442 -- Check that Typ is a remote access-to-subprogram type
2446 -- Prefix (N) must statically denote a remote subprogram
2447 -- declared in a package specification.
2451 Attr = Attribute_Unrestricted_Access
2452 then
2467 or else
2469 then
2471 Error_Msg_N
2473 N);
2476 -- If we are generating code in distributed mode, perform
2477 -- semantic checks against corresponding remote entities.
2479 if Expander_Active
2481 then
2482 Check_Subtype_Conformant
2484 Old_Id => Designated_Type
2510 then
2515 -- Return if already analyzed
2522 -- Any case of Any_Type as the Etype value means that we had a
2523 -- previous error.
2532 -- The resolution of an Expression_With_Actions is determined by
2533 -- its Expression, but if the node comes from source it is a
2534 -- Declare_Expression and requires scope management.
2539 else
2546 -- The resolution of a conditional expression that is the operand of a
2547 -- type conversion is determined by the conversion (RM 4.5.7(10/3)).
2551 then
2555 -- If not overloaded, then we know the type, and all that needs doing
2556 -- is to check that this type is compatible with the context. But note
2557 -- that we may have an operator with no interpretation in Ada 2022 for
2558 -- the case of possible user-defined literals as operands.
2567 then
2568 -- Ignore privacy for streaming or Put_Image routines
2570 else
2576 -- In the overloaded case, we must select the interpretation that
2577 -- is compatible with the context (i.e. the type passed to Resolve)
2579 else
2582 -- Loop through possible interpretations
2591 -- We are only interested in interpretations that are compatible
2592 -- with the expected type, any other interpretations are ignored.
2597 Write_Eol;
2600 else
2601 -- Skip the current interpretation if it is disabled by an
2602 -- abstract operator. This action is performed only when the
2603 -- type against which we are resolving is the same as the
2604 -- type of the interpretation.
2610 then
2618 -- First matching interpretation
2626 -- Matching interpretation that is not the first, maybe an
2627 -- error, but there are some cases where preference rules are
2628 -- used to choose between the two possibilities. These and
2629 -- some more obscure cases are handled in Disambiguate.
2631 else
2632 -- If the current statement is part of a predefined library
2633 -- unit, then all interpretations which come from user level
2634 -- packages should not be considered. Check previous and
2635 -- current one.
2643 -- Previous interpretation must be discarded
2653 -- Otherwise apply further disambiguation steps
2658 -- Disambiguation has succeeded. Skip the remaining
2659 -- interpretations.
2669 else
2670 -- Before we issue an ambiguity complaint, check for the
2671 -- case of a subprogram call where at least one of the
2672 -- arguments is Any_Type, and if so suppress the message,
2673 -- since it is a cascaded error. This can also happen for
2674 -- a generalized indexing operation.
2679 then
2680 declare
2684 begin
2700 Write_Eol;
2713 then
2718 then
2722 -- Not that special case, so issue message using the flag
2723 -- Ambiguous to control printing of the header message
2724 -- only at the start of an ambiguous set.
2729 then
2730 Error_Msg_N
2733 else
2734 Error_Msg_NE -- CODEFIX
2742 Error_Msg_N
2744 else
2745 Error_Msg_N -- CODEFIX
2751 then
2752 Report_Ambiguous_Argument;
2758 -- By default, the error message refers to the candidate
2759 -- interpretation. But if it is a predefined operator, it
2760 -- is implicitly declared at the declaration of the type
2761 -- of the operand. Recover the sloc of that declaration
2762 -- for the error message.
2768 Standard_Standard
2769 then
2774 then
2782 Standard_Standard
2783 then
2788 then
2792 -- If this is an indirect call, use the subprogram_type
2793 -- in the message, to have a meaningful location. Also
2794 -- indicate if this is an inherited operation, created
2795 -- by a type declaration.
2800 then
2802 Error_Msg_Sloc :=
2804 else
2811 then
2812 -- Special-case the message for universal_fixed
2813 -- operators, which are not declared with the type
2814 -- of the operand, but appear forever in Standard.
2818 then
2819 Error_Msg_N
2822 else
2823 Error_Msg_N
2827 elsif
2829 then
2830 Error_Msg_N
2832 else
2833 Error_Msg_N -- CODEFIX
2840 -- We have a matching interpretation, Expr_Type is the type
2841 -- from this interpretation, and Seen is the entity.
2843 -- For an operator, just set the entity name. The type will be
2844 -- set by the specific operator resolution routine.
2851 | N_Character_Literal
2852 | N_Delta_Aggregate
2853 | N_If_Expression
2854 then
2857 -- AI05-0139-2: Expression is overloaded because type has
2858 -- implicit dereference. The context may be the one that
2859 -- requires implicit dereferemce.
2865 -- If the expression is an entity, generate a reference
2866 -- to it, as this is not done for an overloaded construct
2867 -- during analysis.
2871 then
2874 -- Examine access discriminants of entity type,
2875 -- to check whether one of them yields the
2876 -- expected type.
2878 declare
2882 begin
2903 then
2904 -- If the node is a general indexing, the dereference is
2905 -- is inserted when resolving the rewritten form, else
2906 -- insert it now.
2910 then
2914 -- For an explicit dereference, attribute reference, range,
2915 -- short-circuit form (which is not an operator node), or call
2916 -- with a name that is an explicit dereference, there is
2917 -- nothing to be done at this point.
2920 | N_And_Then
2921 | N_Explicit_Dereference
2922 | N_Identifier
2923 | N_Indexed_Component
2924 | N_Or_Else
2925 | N_Range
2926 | N_Selected_Component
2927 | N_Slice
2929 then
2932 -- For procedure or function calls, set the type of the name,
2933 -- and also the entity pointer for the prefix.
2937 then
2944 then
2949 -- For all other cases, just set the type of the Name
2951 else
2959 -- Move to next interpretation
2967 -- At this stage Found indicates whether or not an acceptable
2968 -- interpretation exists. If not, then we have an error, except that if
2969 -- the context is Any_Type as a result of some other error, then we
2970 -- suppress the error report.
2975 -- If type we are looking for is Void, then this is the procedure
2976 -- call case, and the error is simply that what we gave is not a
2977 -- procedure name (we think of procedure calls as expressions with
2978 -- types internally, but the user doesn't think of them this way).
2982 -- Special case message if function used as a procedure
2987 then
2988 Error_Msg_NE
2991 Error_Msg_N
2995 -- Otherwise give general message (not clear what cases this
2996 -- covers, but no harm in providing for them).
2998 else
3004 -- Otherwise we do have a subexpression with the wrong type
3006 -- Check for the case of an allocator which uses an access type
3007 -- instead of the designated type. This is a common error and we
3008 -- specialize the message, posting an error on the operand of the
3009 -- allocator, complaining that we expected the designated type of
3010 -- the allocator.
3016 then
3020 -- Check for view mismatch on Null in instances, for which the
3021 -- view-swapping mechanism has no identifier.
3027 then
3032 -- Check for an aggregate. Sometimes we can get bogus aggregates
3033 -- from misuse of parentheses, and we are about to complain about
3034 -- the aggregate without even looking inside it.
3036 -- Instead, if we have an aggregate of type Any_Composite, then
3037 -- analyze and resolve the component fields, and then only issue
3038 -- another message if we get no errors doing this (otherwise
3039 -- assume that the errors in the aggregate caused the problem).
3043 then
3046 then
3055 -- Disable expansion in any case. If there is a type mismatch
3056 -- it may be fatal to try to expand the aggregate. The flag
3057 -- would otherwise be set to false when the error is posted.
3061 declare
3063 -- Check one aggregate, and set Found to True if we have a
3064 -- definite error in any of its elements
3067 -- Check one element of aggregate and set Found to True if
3068 -- we definitely have an error in the element.
3070 ----------------
3071 -- Check_Aggr --
3072 ----------------
3077 begin
3090 -- If this is a default-initialized component, then
3091 -- there is nothing to check. The box will be
3092 -- replaced by the appropriate call during late
3093 -- expansion.
3097 then
3106 ----------------
3107 -- Check_Elmt --
3108 ----------------
3111 begin
3112 -- If we have a nested aggregate, go inside it (to
3113 -- attempt a naked analyze-resolve of the aggregate can
3114 -- cause undesirable cascaded errors). Do not resolve
3115 -- expression if it needs a type from context, as for
3116 -- integer * fixed expression.
3121 else
3126 then
3136 begin
3141 -- Check whether the node is a literal or a named number or a
3142 -- conditional expression whose dependent expressions are all
3143 -- literals or named numbers.
3149 -- Looks like we have a type error, but check for special case
3150 -- of Address wanted, integer found, with the configuration pragma
3151 -- Allow_Integer_Address active. If we have this case, introduce
3152 -- an unchecked conversion to allow the integer expression to be
3153 -- treated as an Address. The reverse case of integer wanted,
3154 -- Address found, is treated in an analogous manner.
3161 -- Under relaxed RM semantics silently replace occurrences of null
3162 -- by System.Null_Address.
3170 -- That special Allow_Integer_Address check did not apply, so we
3171 -- have a real type error. If an error message was issued already,
3172 -- Found got reset to True, so if it's still False, issue standard
3173 -- Wrong_Type message.
3177 declare
3180 begin
3186 -- Protected operation: retrieve operation name
3190 else
3195 Error_Msg_NE
3201 declare
3205 begin
3212 Error_Msg_NE
3218 else
3222 -- Recognize the case of a quantified expression being mistaken
3223 -- for an iterated component association because the user
3224 -- forgot the "all" or "some" keyword after "for". Because the
3225 -- error message starts with "missing ALL", we automatically
3226 -- benefit from the associated CODEFIX, which requires that
3227 -- the message is located on the identifier following "for"
3228 -- in order for the CODEFIX to insert "all" in the right place.
3233 = N_Iterated_Component_Association
3235 then
3236 if Present
3237 (Iterator_Specification
3239 then
3240 Error_Msg_N -- CODEFIX
3242 Defining_Identifier
3243 (Iterator_Specification
3245 else
3246 Error_Msg_N -- CODEFIX
3248 Defining_Identifier
3252 -- For an operator with no interpretation, check whether one of
3253 -- its operands may be a user-defined literal.
3258 else
3262 else
3268 Resolution_Failed;
3271 -- Test if we have more than one interpretation for the context
3274 Resolution_Failed;
3277 -- Only one interpretation
3279 else
3280 -- Prevent implicit conversions between access-to-subprogram types
3281 -- with different strub modes. Explicit conversions are acceptable in
3282 -- some circumstances. We don't have to be concerned about data or
3283 -- access-to-data types. Conversions between data types can safely
3284 -- drop or add strub attributes from types, because strub effects are
3285 -- associated with the locations rather than values. E.g., converting
3286 -- a hypothetical Strub_Integer variable to Integer would load the
3287 -- value from the variable, enabling stack scrabbing for the
3288 -- enclosing subprogram, and then convert the value to Integer. As
3289 -- for conversions between access-to-data types, that's no different
3290 -- from any other case of type punning.
3296 then
3297 Check_Same_Strub_Mode
3301 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3302 -- the "+" on T is abstract, and the operands are of universal type,
3303 -- the above code will have (incorrectly) resolved the "+" to the
3304 -- universal one in Standard. Therefore check for this case and give
3305 -- an error. We can't do this earlier, because it would cause legal
3306 -- cases to get errors (when some other type has an abstract "+").
3312 then
3317 then
3318 Nondispatching_Call_To_Abstract_Operation
3327 -- Here we have an acceptable interpretation for the context
3329 -- Propagate type information and normalize tree for various
3330 -- predefined operations. If the context only imposes a class of
3331 -- types, rather than a specific type, propagate the actual type
3332 -- downward.
3338 Typ = Any_Discrete
3339 then
3342 -- Any_Fixed is legal in a real context only if a specific fixed-
3343 -- point type is imposed. If Norman Cohen can be confused by this,
3344 -- it deserves a separate message.
3348 then
3355 -- A user-defined operator is transformed into a function call at
3356 -- this point, so that further processing knows that operators are
3357 -- really operators (i.e. are predefined operators). User-defined
3358 -- operators that are intrinsic are just renamings of the predefined
3359 -- ones, and need not be turned into calls either, but if they rename
3360 -- a different operator, we must transform the node accordingly.
3361 -- Instantiations of Unchecked_Conversion are intrinsic but are
3362 -- treated as functions, even if given an operator designator.
3367 then
3372 and then
3374 N_Subprogram_Renaming_Declaration
3375 then
3378 -- If the node is rewritten, it will be fully resolved in
3379 -- Rewrite_Renamed_Operator.
3388 when N_Aggregate =>
3389 Resolve_Aggregate (N, Ctx_Type);
3391 when N_Allocator =>
3392 Resolve_Allocator (N, Ctx_Type);
3394 when N_Short_Circuit =>
3395 Resolve_Short_Circuit (N, Ctx_Type);
3397 when N_Attribute_Reference =>
3398 Resolve_Attribute (N, Ctx_Type);
3400 when N_Case_Expression =>
3401 Resolve_Case_Expression (N, Ctx_Type);
3403 when N_Character_Literal =>
3404 Resolve_Character_Literal (N, Ctx_Type);
3406 when N_Delta_Aggregate =>
3407 Resolve_Delta_Aggregate (N, Ctx_Type);
3409 when N_Expanded_Name =>
3410 Resolve_Entity_Name (N, Ctx_Type);
3412 when N_Explicit_Dereference =>
3413 Resolve_Explicit_Dereference (N, Ctx_Type);
3415 when N_Expression_With_Actions =>
3416 Resolve_Expression_With_Actions (N, Ctx_Type);
3418 when N_Extension_Aggregate =>
3419 Resolve_Extension_Aggregate (N, Ctx_Type);
3421 when N_External_Initializer =>
3422 Resolve_External_Initializer (N, Ctx_Type);
3424 when N_Function_Call =>
3425 Resolve_Call (N, Ctx_Type);
3427 when N_Identifier =>
3428 Resolve_Entity_Name (N, Ctx_Type);
3430 when N_If_Expression =>
3431 Resolve_If_Expression (N, Ctx_Type);
3433 when N_Indexed_Component =>
3434 Resolve_Indexed_Component (N, Ctx_Type);
3436 when N_Integer_Literal =>
3437 Resolve_Integer_Literal (N, Ctx_Type);
3439 when N_Membership_Test =>
3440 Resolve_Membership_Op (N, Ctx_Type);
3442 when N_Null =>
3443 Resolve_Null (N, Ctx_Type);
3445 when N_Op_And
3446 | N_Op_Or
3447 | N_Op_Xor
3448 =>
3449 Resolve_Logical_Op (N, Ctx_Type);
3451 when N_Op_Eq
3452 | N_Op_Ne
3453 =>
3454 Resolve_Equality_Op (N, Ctx_Type);
3456 when N_Op_Ge
3457 | N_Op_Gt
3458 | N_Op_Le
3459 | N_Op_Lt
3460 =>
3461 Resolve_Comparison_Op (N, Ctx_Type);
3463 when N_Op_Not =>
3464 Resolve_Op_Not (N, Ctx_Type);
3466 when N_Op_Add
3467 | N_Op_Divide
3468 | N_Op_Mod
3469 | N_Op_Multiply
3470 | N_Op_Rem
3471 | N_Op_Subtract
3472 =>
3473 Resolve_Arithmetic_Op (N, Ctx_Type);
3475 when N_Op_Concat =>
3476 Resolve_Op_Concat (N, Ctx_Type);
3478 when N_Op_Expon =>
3479 Resolve_Op_Expon (N, Ctx_Type);
3481 when N_Op_Abs
3482 | N_Op_Minus
3483 | N_Op_Plus
3484 =>
3485 Resolve_Unary_Op (N, Ctx_Type);
3487 when N_Op_Shift =>
3488 Resolve_Shift (N, Ctx_Type);
3490 when N_Procedure_Call_Statement =>
3491 Resolve_Call (N, Ctx_Type);
3493 when N_Operator_Symbol =>
3494 Resolve_Operator_Symbol (N, Ctx_Type);
3496 when N_Qualified_Expression =>
3497 Resolve_Qualified_Expression (N, Ctx_Type);
3499 -- Why is the following null, needs a comment ???
3501 when N_Quantified_Expression =>
3502 null;
3504 when N_Raise_Expression =>
3505 Resolve_Raise_Expression (N, Ctx_Type);
3507 when N_Raise_xxx_Error =>
3508 Set_Etype (N, Ctx_Type);
3510 when N_Range =>
3511 Resolve_Range (N, Ctx_Type);
3513 when N_Real_Literal =>
3514 Resolve_Real_Literal (N, Ctx_Type);
3516 when N_Reference =>
3517 Resolve_Reference (N, Ctx_Type);
3519 when N_Selected_Component =>
3520 Resolve_Selected_Component (N, Ctx_Type);
3522 when N_Slice =>
3523 Resolve_Slice (N, Ctx_Type);
3525 when N_String_Literal =>
3526 Resolve_String_Literal (N, Ctx_Type);
3528 when N_Interpolated_String_Literal =>
3529 Resolve_Interpolated_String_Literal (N, Ctx_Type);
3531 when N_Target_Name =>
3532 Resolve_Target_Name (N, Ctx_Type);
3534 when N_Type_Conversion =>
3535 Resolve_Type_Conversion (N, Ctx_Type);
3537 when N_Unchecked_Expression =>
3538 Resolve_Unchecked_Expression (N, Ctx_Type);
3540 when N_Unchecked_Type_Conversion =>
3541 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3542 end case;
3544 -- Mark relevant use-type and use-package clauses as effective using
3545 -- the original node because constant folding may have occurred and
3546 -- removed references that need to be examined.
3548 if Nkind (Original_Node (N)) in N_Op then
3549 Mark_Use_Clauses (Original_Node (N));
3550 end if;
3552 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3553 -- expression of an anonymous access type that occurs in the context
3554 -- of a named general access type, except when the expression is that
3555 -- of a membership test. This ensures proper legality checking in
3556 -- terms of allowed conversions (expressions that would be illegal to
3557 -- convert implicitly are allowed in membership tests).
3559 if Ada_Version >= Ada_2012
3560 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3561 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3562 and then Nkind (Parent (N)) not in N_Membership_Test
3563 then
3564 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3565 Analyze_And_Resolve (N, Ctx_Type);
3566 end if;
3568 -- If the subexpression was replaced by a non-subexpression, then
3569 -- all we do is to expand it. The only legitimate case we know of
3570 -- is converting procedure call statement to entry call statements,
3571 -- but there may be others, so we are making this test general.
3573 if Nkind (N) not in N_Subexpr then
3574 Debug_A_Exit ("resolving ", N, " (done)");
3575 Expand (N);
3576 return;
3577 end if;
3579 -- The expression is definitely NOT overloaded at this point, so
3580 -- we reset the Is_Overloaded flag to avoid any confusion when
3581 -- reanalyzing the node.
3583 Set_Is_Overloaded (N, False);
3585 -- Freeze expression type, entity if it is a name, and designated
3586 -- type if it is an allocator (RM 13.14(10,11,13)).
3588 -- Now that the resolution of the type of the node is complete, and
3589 -- we did not detect an error, we can expand this node. We skip the
3590 -- expand call if we are in a default expression, see section
3591 -- "Handling of Default Expressions" in Sem spec.
3593 Debug_A_Exit ("resolving ", N, " (done)");
3595 -- We unconditionally freeze the expression, even if we are in
3596 -- default expression mode (the Freeze_Expression routine tests this
3597 -- flag and only freezes static types if it is set).
3599 -- Ada 2012 (AI05-177): The declaration of an expression function
3600 -- does not cause freezing, but we never reach here in that case.
3601 -- Here we are resolving the corresponding expanded body, so we do
3602 -- need to perform normal freezing.
3604 -- As elsewhere we do not emit freeze node within a generic.
3606 if not Inside_A_Generic then
3607 Freeze_Expression (N);
3608 end if;
3610 -- Now we can do the expansion
3612 Expand (N);
3613 end if;
3614 end Resolve;
3616 -------------
3617 -- Resolve --
3618 -------------
3620 -- Version with check(s) suppressed
3622 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3623 begin
3624 if Suppress = All_Checks then
3625 declare
3626 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3627 begin
3628 Scope_Suppress.Suppress := (others => True);
3629 Resolve (N, Typ);
3630 Scope_Suppress.Suppress := Sva;
3631 end;
3633 else
3634 declare
3635 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3636 begin
3637 Scope_Suppress.Suppress (Suppress) := True;
3638 Resolve (N, Typ);
3639 Scope_Suppress.Suppress (Suppress) := Svg;
3640 end;
3641 end if;
3642 end Resolve;
3644 -------------
3645 -- Resolve --
3646 -------------
3648 -- Version with implicit type
3650 procedure Resolve (N : Node_Id) is
3651 begin
3652 Resolve (N, Etype (N));
3653 end Resolve;
3655 ---------------------
3656 -- Resolve_Actuals --
3657 ---------------------
3659 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3660 Loc : constant Source_Ptr := Sloc (N);
3661 A : Node_Id;
3662 A_Typ : Entity_Id := Empty; -- init to avoid warning
3663 F : Entity_Id;
3664 F_Typ : Entity_Id;
3665 Prev : Node_Id := Empty;
3666 Orig_A : Node_Id;
3667 Real_F : Entity_Id := Empty; -- init to avoid warning
3669 Real_Subp : Entity_Id;
3670 -- If the subprogram being called is an inherited operation for
3671 -- a formal derived type in an instance, Real_Subp is the subprogram
3672 -- that will be called. It may have different formal names than the
3673 -- operation of the formal in the generic, so after actual is resolved
3674 -- the name of the actual in a named association must carry the name
3675 -- of the actual of the subprogram being called.
3677 procedure Check_Aliased_Parameter;
3678 -- Check rules on aliased parameters and related accessibility rules
3679 -- in (RM 3.10.2 (10.2-10.4)).
3681 procedure Check_Argument_Order;
3682 -- Performs a check for the case where the actuals are all simple
3683 -- identifiers that correspond to the formal names, but in the wrong
3684 -- order, which is considered suspicious and cause for a warning.
3686 procedure Check_Prefixed_Call;
3687 -- If the original node is an overloaded call in prefix notation,
3689 -- Try_Object_Operation has already verified that there is a valid
3690 -- interpretation, but the form of the actual can only be determined
3691 -- once the primitive operation is identified.
3694 -- If the actual is missing in a call, insert in the actuals list
3695 -- an instance of the default expression. The insertion is always
3696 -- a named association.
3699 -- Check whether T1 and T2, or their full views, are derived from a
3700 -- common type. Used to enforce the restrictions on array conversions
3701 -- of AI95-00246.
3704 -- Predicate to determine whether an actual that is a concatenation
3705 -- will be evaluated statically and does not need a transient scope.
3706 -- This must be determined before the actual is resolved and expanded
3707 -- because if needed the transient scope must be introduced earlier.
3709 -----------------------------
3710 -- Check_Aliased_Parameter --
3711 -----------------------------
3716 begin
3724 else
3731 -- In a generic body assume the worst for generic formals:
3732 -- they can have a constrained partial view (AI05-041).
3736 and then not Object_Type_Has_Constrained_Partial_View
3738 then
3741 else
3746 else
3758 then
3766 then
3767 Error_Msg_N
3773 --------------------------
3774 -- Check_Argument_Order --
3775 --------------------------
3778 begin
3779 -- Nothing to do if no parameters, or original node is neither a
3780 -- function call nor a procedure call statement (happens in the
3781 -- operator-transformed-to-function call case), or the call is to an
3782 -- operator symbol (which is usually in infix form), or the call does
3783 -- not come from source, or this warning is off.
3785 if not Warn_On_Parameter_Order
3791 N_Defining_Operator_Symbol)
3793 then
3797 declare
3800 begin
3801 -- Nothing to do if only one parameter
3807 -- Here if at least two arguments
3809 declare
3815 -- Set True if an out of order case is found
3817 begin
3818 -- Collect identifier names of actuals, fail if any actual is
3819 -- not a simple identifier, and record max length of name.
3825 else
3831 -- If we got this far, all actuals are identifiers and the list
3832 -- of their names is stored in the Actuals array.
3837 -- If we ran out of formals, that's odd, probably an error
3838 -- which will be detected elsewhere, but abandon the search.
3844 -- If name matches and is in order OK
3849 else
3850 -- If no match, see if it is elsewhere in list and if so
3851 -- flag potential wrong order if type is compatible.
3855 and then
3857 then
3863 -- No match
3871 -- If Formals left over, also probably an error, skip warning
3877 -- Here we give the warning if something was out of order
3880 Error_Msg_N
3887 -------------------------
3888 -- Check_Prefixed_Call --
3889 -------------------------
3897 begin
3898 -- Check whether the call is a prefixed call, with or without
3899 -- additional actuals.
3903 -- Introduce dereference on object in prefix
3907 then
3908 New_Actual :=
3914 -- Conversely, if the formal is an access parameter and the object
3915 -- is not an access type or a reference type (i.e. a type with the
3916 -- Implicit_Dereference aspect specified), add an implicit 'Access
3917 -- to the prefix. Its analysis will check that the object is
3918 -- aliased.
3923 or else
3924 not Is_Access_Type
3925 (Designated_Type
3927 then
3937 --------------------
3938 -- Insert_Default --
3939 --------------------
3945 begin
3946 -- Missing argument in call, nothing to insert
3951 else
3952 -- Note that we do a full New_Copy_Tree, so that any associated
3953 -- Itypes are properly copied. This may not be needed any more,
3954 -- but it does no harm as a safety measure. Defaults of a generic
3955 -- formal may be out of bounds of the corresponding actual (see
3956 -- cc1311b) and an additional check may be required.
3958 Actval :=
3959 New_Copy_Tree
3964 -- Propagate dimension information, if any.
3970 then
3976 then
3979 then
3980 -- If default is a real literal, do not introduce a
3981 -- conversion whose effect may depend on the run-time
3982 -- size of universal real.
3986 else
3997 -- Resolve aggregates with their base type, to avoid scope
3998 -- anomalies: the subtype was first built in the subprogram
3999 -- declaration, and the current call may be nested.
4003 else
4007 else
4010 -- See note above concerning aggregates
4014 then
4017 -- Resolve entities with their own type, which may differ from
4018 -- the type of a reference in a generic context because of the
4019 -- trick used in Save_Global_References.Set_Global_Type to set
4020 -- full views forcefully, which did not anticipate the need to
4021 -- re-analyze default values in calls.
4026 -- Ditto for calls whose name is an entity, for the same reason
4030 then
4033 else
4038 -- If default is a tag indeterminate function call, propagate tag
4039 -- to obtain proper dispatching.
4043 then
4048 -- If the default expression raises constraint error, then just
4049 -- silently replace it with an N_Raise_Constraint_Error node, since
4050 -- we already gave the warning on the subprogram spec. If node is
4051 -- already a Raise_Constraint_Error leave as is, to prevent loops in
4052 -- the warnings removal machinery.
4056 then
4065 Assoc :=
4070 -- Case of insertion is first named actual
4074 then
4081 else
4085 else
4089 -- Case of insertion is not first named actual
4091 else
4092 Set_Next_Named_Actual
4104 -------------------
4105 -- Same_Ancestor --
4106 -------------------
4112 begin
4115 then
4121 then
4128 --------------------------
4129 -- Static_Concatenation --
4130 --------------------------
4133 begin
4140 -- Concatenation is static when both operands are static and
4141 -- the concatenation operator is a predefined one.
4144 and then
4146 and then
4151 declare
4153 begin
4156 and then
4160 else
4166 -- Start of processing for Resolve_Actuals
4168 begin
4169 Check_Argument_Order;
4173 and then In_Instance
4176 then
4178 else
4183 Check_Prefixed_Call;
4197 -- If we have an error in any formal or actual, indicated by a type
4198 -- of Any_Type, then abandon resolution attempt, and set result type
4199 -- to Any_Type.
4206 -- For the peculiar case of a user-defined comparison or equality
4207 -- operator that does not return a boolean type, the operands may
4208 -- have been ambiguous for the predefined operator and, therefore,
4209 -- marked with Any_Type. Since the operation has been resolved to
4210 -- the user-defined operator, that is irrelevant, so reset Etype.
4214 then
4217 -- Also skip this if the actual is a Raise_Expression, whose type
4218 -- is imposed from context.
4223 else
4229 -- Case where actual is present
4231 -- If the actual is an entity, generate a reference to it now. We
4232 -- do this before the actual is resolved, because a formal of some
4233 -- protected subprogram, or a task discriminant, will be rewritten
4234 -- during expansion, and the source entity reference may be lost.
4239 then
4240 -- Annotate the tree by creating a variable reference marker when
4241 -- the actual denotes a variable reference, in case the reference
4242 -- is folded or optimized away. The variable reference marker is
4243 -- automatically saved for later examination by the ABE Processing
4244 -- phase. The status of the reference is set as follows:
4246 -- status mode
4247 -- read IN, IN OUT
4248 -- write IN OUT, OUT
4250 if Needs_Variable_Reference_Marker
4253 then
4254 Build_Variable_Reference_Marker
4265 then
4272 -- RM 6.4.1(12): For an out parameter that is passed by
4273 -- copy, the formal parameter object is created, and:
4275 -- * For an access type, the formal parameter is initialized
4276 -- from the value of the actual, without checking that the
4277 -- value satisfies any constraint, any predicate, or any
4278 -- exclusion of the null value.
4280 -- * For a scalar type that has the Default_Value aspect
4281 -- specified, the formal parameter is initialized from the
4282 -- value of the actual, without checking that the value
4283 -- satisfies any constraint or any predicate.
4284 -- I do not understand why this case is included??? this is
4285 -- not a case where an OUT parameter is treated as IN OUT.
4287 -- * For a composite type with discriminants or that has
4288 -- implicit initial values for any subcomponents, the
4289 -- behavior is as for an in out parameter passed by copy.
4291 -- Hence for these cases we generate the read reference now
4292 -- (the write reference will be generated later by
4293 -- Note_Possible_Modification).
4296 and then
4298 or else
4300 and then
4302 or else
4305 or else Is_Partially_Initialized_Type
4307 then
4317 then
4318 -- If style checking mode on, check match of formal name
4326 -- If the formal is Out or In_Out, do not resolve and expand the
4327 -- conversion, because it is subsequently expanded into explicit
4328 -- temporaries and assignments. However, the object of the
4329 -- conversion can be resolved. An exception is the case of tagged
4330 -- type conversion with a class-wide actual. In that case we want
4331 -- the tag check to occur and no temporary will be needed (no
4332 -- representation change can occur) and the parameter is passed by
4333 -- reference, so we go ahead and resolve the type conversion.
4334 -- Another exception is the case of reference to component or
4335 -- subcomponent of a bit-packed array, in which case we want to
4336 -- defer expansion to the point the in and out assignments are
4337 -- performed.
4343 then
4344 declare
4347 begin
4348 -- Check RM 4.6 (24.2/2)
4352 then
4353 -- In a view conversion, the conversion must be legal in
4354 -- both directions, and thus both component types must be
4355 -- aliased, or neither (4.6 (8)).
4357 -- Check RM 4.6 (24.8/2)
4361 then
4362 -- This normally illegal conversion is legal in an
4363 -- expanded instance body because of RM 12.3(11).
4364 -- At runtime, conversion must create a new object.
4367 Error_Msg_N
4372 -- Check RM 4.6 (24/3)
4375 -- Check view conv between unrelated by ref array
4376 -- types.
4380 then
4381 Error_Msg_N
4385 -- In Ada 2005 mode, check view conversion component
4386 -- type cannot be private, tagged, or volatile. Note
4387 -- that we only apply this to source conversions. The
4388 -- generated code can contain conversions which are
4389 -- not subject to this test, and we cannot extract the
4390 -- component type in such cases since it is not
4391 -- present.
4395 then
4396 declare
4399 begin
4404 then
4405 Error_Msg_N
4415 -- AI12-0074 & AI12-0377
4416 -- Check 6.4.1: If the mode is out, the actual parameter is
4417 -- a view conversion, and the type of the formal parameter
4418 -- is a scalar type, then either:
4419 -- - the target and operand type both do not have the
4420 -- Default_Value aspect specified; or
4421 -- - the target and operand type both have the
4422 -- Default_Value aspect specified, and there shall exist
4423 -- a type (other than a root numeric type) that is an
4424 -- ancestor of both the target type and the operand
4425 -- type.
4429 then
4432 then
4433 Error_Msg_N
4438 then
4439 Error_Msg_N
4446 -- Resolve expression if conversion is all OK
4451 then
4455 -- In GNATprove mode, add a range check flag on scalar
4456 -- conversions for IN OUT parameters. The check may be
4457 -- needed on entry from the call.
4459 if GNATprove_Mode
4462 then
4466 -- If the actual is a function call that returns a limited
4467 -- unconstrained object that needs finalization, create a
4468 -- transient scope for it, so that it can receive the proper
4469 -- finalization list.
4471 elsif Expander_Active
4477 then
4481 -- A small optimization: if one of the actuals is a concatenation
4482 -- create a block around a procedure call to recover stack space.
4483 -- This alleviates stack usage when several procedure calls in
4484 -- the same statement list use concatenation. We do not perform
4485 -- this wrapping for code statements, where the argument is a
4486 -- static string, and we want to preserve warnings involving
4487 -- sequences of such statements.
4489 elsif Expander_Active
4495 then
4499 else
4503 and then
4506 then
4507 Error_Msg_N
4520 -- (Ada 2005: AI-251): If the actual is an allocator whose
4521 -- directly designated type is a class-wide interface, we build
4522 -- an anonymous access type to use it as the type of the
4523 -- allocator. Later, when the subprogram call is expanded, if
4524 -- the interface has a secondary dispatch table the expander
4525 -- will add a type conversion to force the correct displacement
4526 -- of the pointer.
4529 declare
4533 begin
4534 -- Displace the pointer to the object to reference its
4535 -- secondary dispatch table.
4539 then
4545 -- Ada 2005, AI-162:If the actual is an allocator, the
4546 -- innermost enclosing statement is the master of the
4547 -- created object. This needs to be done with expansion
4548 -- enabled only, otherwise the transient scope will not
4549 -- be removed in the expansion of the wrapped construct.
4551 if Expander_Active
4554 then
4555 Establish_Transient_Scope
4565 -- (Ada 2005): The call may be to a primitive operation of a
4566 -- tagged synchronized type, declared outside of the type. In
4567 -- this case the controlling actual must be converted to its
4568 -- corresponding record type, which is the formal type. The
4569 -- actual may be a subtype, either because of a constraint or
4570 -- because it is a generic actual, so use base type to locate
4571 -- concurrent type.
4578 then
4579 -- If the actual is overloaded, look for an interpretation
4580 -- that has a synchronized type.
4585 else
4586 declare
4590 begin
4595 then
4605 declare
4608 begin
4611 else
4615 -- Tagged synchronized type (case 1): the actual is a
4616 -- concurrent type.
4620 then
4622 Unchecked_Convert_To
4626 -- Tagged synchronized type (case 2): the formal is a
4627 -- concurrent type.
4630 and then Present
4635 then
4638 -- Common case
4640 else
4645 -- Not a synchronized operation
4647 else
4655 -- If A_Typ is complete and F_Typ is not, then adjust F_Typ
4660 then
4664 -- An actual cannot be of an untagged incomplete view; the result
4665 -- object of a function call cannot be of an incomplete view
4666 -- (RM 3.10.1(10)).
4671 then
4672 -- No error if the call is placed in the initializing
4673 -- expression of a component of the full-view of the
4674 -- incomplete type. For example:
4676 -- type T;
4677 -- function F (Obj : T) return Integer;
4679 -- type T is record
4680 -- Data : Integer := F (T);
4681 -- end record;
4685 and then In_Spec_Expression
4686 and then In_Default_Expr
4687 then
4690 -- No error if the call is performed in pre/postconditions, and
4691 -- it is an incomplete type of a limited-with clause.
4696 and then
4697 (In_Spec_Expression
4698 or else
4700 then
4705 Error_Msg_N
4707 else
4708 Error_Msg_N
4711 else
4716 -- For mode IN, if actual is an entity, and the type of the formal
4717 -- has warnings suppressed, then we reset Never_Set_In_Source for
4718 -- the calling entity. The reason for this is to catch cases like
4719 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4720 -- uses trickery to modify an IN parameter.
4727 then
4731 -- Perform error checks for IN and IN OUT parameters
4735 -- Check unset reference. For scalar parameters, it is clearly
4736 -- wrong to pass an uninitialized value as either an IN or
4737 -- IN-OUT parameter. For composites, it is also clearly an
4738 -- error to pass a completely uninitialized value as an IN
4739 -- parameter, but the case of IN OUT is trickier. We prefer
4740 -- not to give a warning here. For example, suppose there is
4741 -- a routine that sets some component of a record to False.
4742 -- It is perfectly reasonable to make this IN-OUT and allow
4743 -- either initialized or uninitialized records to be passed
4744 -- in this case.
4746 -- For partially initialized composite values, we also avoid
4747 -- warnings, since it is quite likely that we are passing a
4748 -- partially initialized value and only the initialized fields
4749 -- will in fact be read in the subprogram.
4754 then
4758 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4759 -- actual to a nested call, since this constitutes a reading of
4760 -- the parameter, which is not allowed.
4765 then
4770 -- In -gnatd.q mode, forget that a given array is constant when
4771 -- it is passed as an IN parameter to a foreign-convention
4772 -- subprogram. This is in case the subprogram evilly modifies the
4773 -- object. Of course, correct code would use IN OUT.
4775 if Debug_Flag_Dot_Q
4781 then
4785 -- Case of OUT or IN OUT parameter
4789 -- For an Out parameter, check for useless assignment. Note
4790 -- that we can't set Last_Assignment this early, because we may
4791 -- kill current values in Resolve_Call, and that call would
4792 -- clobber the Last_Assignment field.
4794 -- Note: call Warn_On_Useless_Assignment before doing the check
4795 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4796 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4797 -- reflects the last assignment, not this one.
4804 then
4809 -- Validate the form of the actual. Note that the call to
4810 -- Is_OK_Variable_For_Out_Formal generates the required
4811 -- reference in this case.
4813 -- A call to an initialization procedure for an aggregate
4814 -- component may initialize a nested component of a constant
4815 -- designated object. In this context the object is variable.
4819 then
4825 then
4826 Error_Msg_N
4831 Error_Msg_N
4838 -- What's the following about???
4842 else
4843 Kill_All_Checks;
4852 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4856 -- Apply predicate tests except in certain special cases. Note
4857 -- that it might be more consistent to apply these only when
4858 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4859 -- for the outbound predicate tests ??? In any case indicate
4860 -- the function being called, for better warnings if the call
4861 -- leads to an infinite recursion.
4867 -- Apply required constraint checks
4880 then
4883 -- For view conversions of a discriminated object, apply
4884 -- check to object itself, the conversion alreay has the
4885 -- proper type.
4889 then
4896 then
4902 then
4905 else
4909 -- Ada 2005 (AI-231): Note that the controlling parameter case
4910 -- already existed in Ada 95, which is partially checked
4911 -- elsewhere (see Checks), and we don't want the warning
4912 -- message to differ.
4917 then
4919 Apply_Compile_Time_Constraint_Error
4925 Apply_Compile_Time_Constraint_Error
4933 -- In a prefixed call, if the prefix is an access type
4934 -- it cannot be null.
4939 then
4942 then
4943 Error_Msg_NE
4949 if Debug_Flag_Underscore_PP
4950 and then
4953 then
4959 -- Checks for OUT parameters and IN OUT parameters
4963 -- If there is a type conversion, make sure the return value
4964 -- meets the constraints of the variable before the conversion.
4969 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4970 -- which would prevent the check from being generated.
4971 -- This is for Starlet only though, so long obsolete.
4976 then
4978 else
4979 Apply_Scalar_Range_Check
4983 -- In addition the return value must meet the constraints
4984 -- of the object type (see the comment below).
4988 else
4989 Apply_Range_Check
4993 -- If no conversion, apply scalar range checks and length check
4994 -- based on the subtype of the actual (NOT that of the formal).
4995 -- This indicates that the check takes place on return from the
4996 -- call. During expansion the required constraint checks are
4997 -- inserted. In GNATprove mode, in the absence of expansion,
4998 -- the flag indicates that the returned value is valid.
5000 else
5006 then
5009 else
5014 -- Note: we do not apply the predicate checks for the case of
5015 -- OUT and IN OUT parameters. They are instead applied in the
5016 -- Expand_Actuals routine in Exp_Ch6.
5019 -- If the formal is of an unconstrained array subtype with fixed
5020 -- lower bound, then sliding to that bound may be needed.
5026 -- An actual associated with an access parameter is implicitly
5027 -- converted to the anonymous access type of the formal and must
5028 -- satisfy the legality checks for access conversions.
5032 Error_Msg_N
5036 -- If the actual is an access selected component of a variable,
5037 -- the call may modify its designated object. It is reasonable
5038 -- to treat this as a potential modification of the enclosing
5039 -- record, to prevent spurious warnings that it should be
5040 -- declared as a constant, because intuitively programmers
5041 -- regard the designated subcomponent as part of the record.
5046 then
5051 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
5055 then
5058 then
5059 Error_Msg_NE
5062 Error_Msg_N
5067 then
5068 Error_Msg_NE
5071 Error_Msg_N
5076 then
5077 Error_Msg_NE
5080 Error_Msg_N
5084 -- Check for nonatomic subcomponent of a full access object
5085 -- in Ada 2022 (RM C.6 (12)).
5090 then
5091 Error_Msg_N
5094 Error_Msg_NE
5100 -- Check that subprograms don't have improper controlling
5101 -- arguments (RM 3.9.2 (9)).
5103 -- A primitive operation may have an access parameter of an
5104 -- incomplete tagged type, but a dispatching call is illegal
5105 -- if the type is still incomplete.
5111 declare
5113 begin
5117 then
5118 Error_Msg_NE
5129 -- Apply legality rule 3.9.2 (9/1)
5131 -- Skip this check on helpers and indirect-call wrappers built to
5132 -- support class-wide preconditions.
5134 -- We make special exception here for mutably tagged types and
5135 -- related calls to their initialization procedures.
5140 and then not In_Instance
5144 -- Ignore mutably tagged types and their use in calls to init
5145 -- procs.
5149 then
5154 Error_Msg_NE
5158 -- Apply the checks described in 3.10.2(27): if the context is a
5159 -- specific access-to-object, the actual cannot be class-wide.
5160 -- Use base type to exclude access_to_subprogram cases.
5167 and then
5172 -- Disable these checks for call to imported C++ subprograms
5174 and then not
5178 then
5179 Error_Msg_N
5184 Error_Msg_NE
5189 Check_Aliased_Parameter;
5193 -- If it is a named association, treat the selector_name as a
5194 -- proper identifier, and mark the corresponding entity.
5198 -- Ignore reference in SPARK mode, as it refers to an entity not
5199 -- in scope at the point of reference, so the reference should
5200 -- be ignored for computing effects of subprograms.
5202 and then not GNATprove_Mode
5203 then
5204 -- If subprogram is overridden, use name of formal that
5205 -- is being called.
5211 else
5225 -- A formal parameter of a specific tagged type whose related
5226 -- subprogram is subject to pragma Extensions_Visible with value
5227 -- "False" cannot act as an actual in a subprogram with value
5228 -- "True" (SPARK RM 6.1.7(3)).
5230 -- No check needed for helpers and indirect-call wrappers built to
5231 -- support class-wide preconditions.
5235 Extensions_Visible_True
5236 and then not
5238 and then
5240 then
5241 Error_Msg_N
5244 Error_Msg_NE
5248 -- The actual parameter of a Ghost subprogram whose formal is of
5249 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5257 then
5258 Error_Msg_NE
5264 else
5269 -- (AI12-0397): The target of a subprogram call that occurs within
5270 -- the expression of an Default_Initial_Condition aspect and has
5271 -- an actual that is the current instance of the type must be
5272 -- either a primitive of the type or a class-wide subprogram,
5273 -- because the type of the current instance in such an aspect is
5274 -- considered to be a notional formal derived type whose only
5275 -- operations correspond to the primitives of the enclosing type.
5276 -- Nonprimitives can be called, but the current instance must be
5277 -- converted rather than passed directly. Note that a current
5278 -- instance of a type with DIC will occur as a reference to an
5279 -- in-mode formal of an enclosing DIC procedure or partial DIC
5280 -- procedure. (It seems that this check should perhaps also apply
5281 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5282 -- aspects???)
5290 -- We check Comes_From_Source to exclude inherited primitives
5291 -- from being flagged, because such subprograms turn out to not
5292 -- always have the Is_Primitive flag set. ???
5298 then
5299 Error_Msg_NE
5306 -- Case where actual is not present
5308 else
5309 Insert_Default;
5320 -----------------------
5321 -- Resolve_Allocator --
5322 -----------------------
5334 procedure Check_Allocator_Discrim_Accessibility
5337 -- Check that accessibility level associated with an access discriminant
5338 -- initialized in an allocator by the expression Disc_Exp is not deeper
5339 -- than the level of the allocator type Alloc_Typ. An error message is
5340 -- issued if this condition is violated. Specialized checks are done for
5341 -- the cases of a constraint expression which is an access attribute or
5342 -- an access discriminant.
5344 procedure Check_Allocator_Discrim_Accessibility_Exprs
5347 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5348 -- across all expressions within a given conditional expression.
5351 -- If the allocator is an actual in a call, it is allowed to be class-
5352 -- wide when the context is not because it is a controlling actual.
5354 -------------------------------------------
5355 -- Check_Allocator_Discrim_Accessibility --
5356 -------------------------------------------
5358 procedure Check_Allocator_Discrim_Accessibility
5361 is
5362 begin
5365 then
5366 Error_Msg_N
5369 -- When the expression is an Access attribute the level of the prefix
5370 -- object must not be deeper than that of the allocator's type.
5374 Attribute_Access
5375 and then Static_Accessibility_Level
5378 then
5379 Error_Msg_N
5381 Disc_Exp);
5383 -- When the expression is an access discriminant the check is against
5384 -- the level of the prefix object.
5388 and then Static_Accessibility_Level
5391 then
5392 Error_Msg_N
5394 Disc_Exp);
5396 -- All other cases are legal
5398 else
5403 -------------------------------------------------
5404 -- Check_Allocator_Discrim_Accessibility_Exprs --
5405 -------------------------------------------------
5407 procedure Check_Allocator_Discrim_Accessibility_Exprs
5410 is
5414 begin
5415 -- When conditional expressions are constant folded we know at
5416 -- compile time which expression to check - so don't bother with
5417 -- the rest of the cases.
5422 -- Non-constant-folded if expressions
5425 -- Check both expressions if they are still present in the face
5426 -- of expansion.
5433 Check_Allocator_Discrim_Accessibility_Exprs
5438 -- Non-constant-folded case expressions
5441 -- Check all alternatives
5445 Check_Allocator_Discrim_Accessibility_Exprs
5451 -- Base case, check the accessibility of the original node of the
5452 -- expression.
5454 else
5459 ----------------------------
5460 -- In_Dispatching_Context --
5461 ----------------------------
5466 begin
5472 -- Start of processing for Resolve_Allocator
5474 begin
5475 -- Replace general access with specific type
5485 -- For qualified expression, resolve the expression using the given
5486 -- subtype (nothing to do for type mark, subtype indication)
5491 and then not In_Dispatching_Context
5492 then
5493 Error_Msg_N
5497 -- Do a full resolution to apply constraint and predicate checks
5502 -- Allocators generated by the build-in-place expansion mechanism
5503 -- are explicitly marked as coming from source but do not need to be
5504 -- checked for limited initialization. To exclude this case, ensure
5505 -- that the parent of the allocator is a source node.
5506 -- The return statement constructed for an Expression_Function does
5507 -- not come from source but requires a limited check.
5511 and then
5513 or else
5517 and then not In_Instance_Body
5518 then
5521 Error_Msg_N
5524 else
5525 Error_Msg_N
5533 -- Calls to build-in-place functions are not currently supported in
5534 -- allocators for access types associated with a simple storage pool.
5535 -- Supporting such allocators may require passing additional implicit
5536 -- parameters to build-in-place functions (or a significant revision
5537 -- of the current b-i-p implementation to unify the handling for
5538 -- multiple kinds of storage pools). ???
5542 then
5543 declare
5546 begin
5548 and then
5549 Present (Get_Rep_Pragma
5551 then
5552 Error_Msg_N
5559 -- A special accessibility check is needed for allocators that
5560 -- constrain access discriminants. The level of the type of the
5561 -- expression used to constrain an access discriminant cannot be
5562 -- deeper than the type of the allocator (in contrast to access
5563 -- parameters, where the level of the actual can be arbitrary).
5565 -- We can't use Valid_Conversion to perform this check because in
5566 -- general the type of the allocator is unrelated to the type of
5567 -- the access discriminant.
5571 then
5578 then
5581 -- Get the first component expression of the aggregate
5591 else
5595 else
5601 Check_Allocator_Discrim_Accessibility_Exprs
5615 else
5620 else
5629 -- For a subtype mark or subtype indication, freeze the subtype
5631 else
5635 Error_Msg_N
5639 -- A special accessibility check is needed for allocators that
5640 -- constrain access discriminants. The level of the type of the
5641 -- expression used to constrain an access discriminant cannot be
5642 -- deeper than the type of the allocator (in contrast to access
5643 -- parameters, where the level of the actual can be arbitrary).
5644 -- We can't use Valid_Conversion to perform this check because
5645 -- in general the type of the allocator is unrelated to the type
5646 -- of the access discriminant.
5651 then
5661 else
5665 Check_Allocator_Discrim_Accessibility_Exprs
5676 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5677 -- check that the level of the type of the created object is not deeper
5678 -- than the level of the allocator's access type, since extensions can
5679 -- now occur at deeper levels than their ancestor types. This is a
5680 -- static accessibility level check; a run-time check is also needed in
5681 -- the case of an initialized allocator with a class-wide argument (see
5682 -- Expand_Allocator_Expression).
5686 then
5687 declare
5690 begin
5695 else
5701 then
5704 Error_Msg_N
5714 -- Do not apply Ada 2005 accessibility checks on a class-wide
5715 -- allocator if the type given in the allocator is a formal
5716 -- type or within a formal package. A run-time check will be
5717 -- performed in the instance.
5721 then
5722 Error_Msg_N
5730 -- Check for allocation from an empty storage pool. But do not complain
5731 -- if it's a return statement for a build-in-place function, because the
5732 -- allocator is there just in case the caller uses an allocator. If the
5733 -- caller does use an allocator, it will be caught at the call site.
5737 then
5740 -- If the context is an unchecked conversion, as may happen within an
5741 -- inlined subprogram, the allocator is being resolved with its own
5742 -- anonymous type. In that case, if the target type has a specific
5743 -- storage pool, it must be inherited explicitly by the allocator type.
5747 then
5748 Set_Associated_Storage_Pool
5756 -- Check that an allocator with task parts isn't for a nested access
5757 -- type when restriction No_Task_Hierarchy applies.
5761 then
5765 -- An illegal allocator may be rewritten as a raise Program_Error
5766 -- statement.
5770 -- Avoid coextension processing for an allocator that is the
5771 -- expansion of a build-in-place function call.
5775 N_Qualified_Expression
5777 N_Function_Call
5778 and then Is_Expanded_Build_In_Place_Call
5780 then
5783 else
5784 -- An anonymous access discriminant is the definition of a
5785 -- coextension.
5789 N_Discriminant_Specification
5790 then
5791 declare
5795 begin
5798 -- Ada 2012 AI05-0052: If the designated type of the
5799 -- allocator is limited, then the allocator shall not
5800 -- be used to define the value of an access discriminant
5801 -- unless the discriminated type is immutably limited.
5806 then
5807 Error_Msg_N
5810 N);
5814 -- Avoid marking an allocator as a dynamic coextension if it is
5815 -- within a static construct.
5820 -- Finalization and deallocation of coextensions utilizes an
5821 -- approximate implementation which does not directly adhere
5822 -- to the semantic rules. Warn on potential issues involving
5823 -- coextensions.
5826 Error_Msg_N
5829 else
5830 Error_Msg_N
5836 -- Cleanup for potential static coextensions
5838 else
5842 -- Objects allocated through anonymous access types are not
5843 -- finalized on time because this involves run-time ownership
5844 -- and currently this property is not available. In rare cases
5845 -- the object might not be finalized at all. Warn on potential
5846 -- issues involving anonymous access-to-controlled types.
5850 then
5851 Error_Msg_N
5861 -- Report a simple error: if the designated object is a local task,
5862 -- its body has not been seen yet, and its activation will fail an
5863 -- elaboration check.
5870 then
5876 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5877 -- type with a task component on a subpool. This action must raise
5878 -- Program_Error at runtime.
5884 then
5896 ---------------------------
5897 -- Resolve_Arithmetic_Op --
5898 ---------------------------
5900 -- Used for resolving all arithmetic operators except exponentiation
5911 -- We do the resolution using the base type, because intermediate values
5912 -- in expressions always are of the base type, not a subtype of it.
5915 -- Returns True if N is in a context that expects "any real type"
5918 -- Return True iff given type is Integer or universal real/integer
5921 -- Choose type of integer literal in fixed-point operation to conform
5922 -- to available fixed-point type. T is the type of the other operand,
5923 -- which is needed to determine the expected type of N.
5926 -- Set operand type to T if universal
5928 -------------------------------
5929 -- Expected_Type_Is_Any_Real --
5930 -------------------------------
5933 begin
5934 -- N is the expression after "delta" in a fixed_point_definition;
5935 -- see RM-3.5.9(6):
5938 | N_Decimal_Fixed_Point_Definition
5940 -- N is one of the bounds in a real_range_specification;
5941 -- see RM-3.5.7(5):
5943 | N_Real_Range_Specification
5945 -- N is the expression of a delta_constraint;
5946 -- see RM-J.3(3):
5948 | N_Delta_Constraint;
5951 -----------------------------
5952 -- Is_Integer_Or_Universal --
5953 -----------------------------
5960 begin
5965 else
5970 then
5981 ----------------------------
5982 -- Set_Mixed_Mode_Operand --
5983 ----------------------------
5989 begin
5992 -- A universal integer literal is resolved as standard integer
5993 -- except in the case of a fixed-point result, where we leave it
5994 -- as universal (to be handled by Exp_Fixd later on)
5998 else
6005 then
6006 -- A universal real can appear in a fixed-type context. We resolve
6007 -- the literal with that context, even though this might raise an
6008 -- exception prematurely (the other operand may be zero).
6015 then
6016 -- Integer arg in mixed-mode operation. Resolve with universal
6017 -- type, in case preference rule must be applied.
6023 -- If the operand is part of a fixed multiplication operation,
6024 -- a conversion will be applied to each operand, so resolve it
6025 -- with its own type.
6030 else
6031 -- Not a mixed-mode operation, resolve with context
6038 -- N may itself be a mixed-mode operation, so use context type
6045 then
6046 -- Must be (fixed * fixed) operation, operand must have one
6047 -- compatible interpretation.
6054 then
6055 -- C * F(X) in a fixed context, where C is a real literal or a
6056 -- fixed-point expression. F must have either a fixed type
6057 -- interpretation or an integer interpretation, but not both.
6064 else
6071 else
6079 -- Reanalyze the literal with the fixed type of the context. If
6080 -- context is Universal_Fixed, we are within a conversion, leave
6081 -- the literal as a universal real because there is no usable
6082 -- fixed type, and the target of the conversion plays no role in
6083 -- the resolution.
6085 declare
6089 begin
6092 else
6098 then
6100 else
6108 -- A universal real conditional expression can appear in a fixed-type
6109 -- context and must be resolved with that context to facilitate the
6110 -- code generation in the back end. However, If the context is
6111 -- Universal_fixed (i.e. as an operand of a multiplication/division
6112 -- involving a fixed-point operand) the conditional expression must
6113 -- resolve to a unique visible fixed_point type, normally Duration.
6118 then
6122 else
6126 else
6131 ----------------------
6132 -- Set_Operand_Type --
6133 ----------------------
6136 begin
6142 -- Start of processing for Resolve_Arithmetic_Op
6144 begin
6148 then
6153 -- Special-case for mixed-mode universal expressions or fixed point type
6154 -- operation: each argument is resolved separately. The same treatment
6155 -- is required if one of the operands of a fixed point operation is
6156 -- universal real, since in this case we don't do a conversion to a
6157 -- specific fixed-point type (instead the expander handles the case).
6159 -- Set the type of the node to its universal interpretation because
6160 -- legality checks on an exponentiation operand need the context.
6165 then
6176 or else
6179 then
6184 -- If context is a fixed type and one operand is integer, the other
6185 -- is resolved with the type of the context.
6190 then
6197 then
6201 -- If both operands are universal and the context is a floating
6202 -- point type, the operands are resolved to the type of the context.
6208 else
6213 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6214 -- multiplying operators from being used when the expected type is
6215 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6216 -- some cases where the expected type is actually Any_Real;
6217 -- Expected_Type_Is_Any_Real takes care of that case.
6221 then
6225 N_Type_Conversion | N_Unchecked_Type_Conversion
6226 then
6233 else
6237 N_Type_Conversion | N_Unchecked_Type_Conversion
6238 then
6239 Error_Msg_N
6244 -- The expected type is "any real type" in contexts like
6246 -- type T is delta <universal_fixed-expression> ...
6248 -- in which case we need to set the type to Universal_Real
6249 -- so that static expression evaluation will work properly.
6253 else
6263 then
6268 -- If no previous errors, this is only possible if one operand is
6269 -- overloaded and the context is universal. Resolve as such.
6274 else
6276 and then
6278 then
6282 -- If the context is Universal_Fixed and the operands are also
6283 -- universal fixed, this is an error, unless there is only one
6284 -- applicable fixed_point type (usually Duration).
6292 else
6297 else
6302 -- If one of the arguments was resolved to a non-universal type.
6303 -- label the result of the operation itself with the same type.
6304 -- Do the same for the universal argument, if any.
6316 -- Set overflow and division checking bit
6323 -- Give warning if explicit division by zero
6327 then
6333 or else
6336 then
6337 -- Specialize the warning message according to the operation.
6338 -- When SPARK_Mode is On, force a warning instead of an error
6339 -- in that case, as this likely corresponds to deactivated
6340 -- code. The following warnings are for the case
6345 -- For division, we have two cases, for float division
6346 -- of an unconstrained float type, on a machine where
6347 -- Machine_Overflows is false, we don't get an exception
6348 -- at run-time, but rather an infinity or Nan. The Nan
6349 -- case is pretty obscure, so just warn about infinities.
6353 and then not Machine_Overflows_On_Target
6354 then
6355 Error_Msg_N
6359 -- For all other cases, we get a Constraint_Error
6361 else
6362 Apply_Compile_Time_Constraint_Error
6369 Apply_Compile_Time_Constraint_Error
6375 Apply_Compile_Time_Constraint_Error
6380 -- Division by zero can only happen with division, rem,
6381 -- and mod operations.
6387 -- Otherwise just set the flag to check at run time
6389 else
6394 -- If Restriction No_Implicit_Conditionals is active, then it is
6395 -- violated if either operand can be negative for mod, or for rem
6396 -- if both operands can be negative.
6400 then
6401 declare
6408 -- Set if corresponding operand might be negative
6410 begin
6411 Determine_Range
6415 Determine_Range
6419 -- Check if we will be generating conditionals. There are two
6420 -- cases where that can happen, first for REM, the only case
6421 -- is largest negative integer mod -1, where the division can
6422 -- overflow, but we still have to give the right result. The
6423 -- front end generates a test for this annoying case. Here we
6424 -- just test if both operands can be negative (that's what the
6425 -- expander does, so we match its logic here).
6427 -- The second case is mod where either operand can be negative.
6428 -- In this case, the back end has to generate additional tests.
6431 or else
6433 then
6444 ------------------
6445 -- Resolve_Call --
6446 ------------------
6461 begin
6462 -- Preserve relevant elaboration-related attributes of the context which
6463 -- are no longer available or very expensive to recompute once analysis,
6464 -- resolution, and expansion are over.
6466 Mark_Elaboration_Attributes
6472 -- The context imposes a unique interpretation with type Typ on a
6473 -- procedure or function call. Find the entity of the subprogram that
6474 -- yields the expected type, and propagate the corresponding formal
6475 -- constraints on the actuals. The caller has established that an
6476 -- interpretation exists, and emitted an error if not unique.
6478 -- First deal with the case of a call to an access-to-subprogram,
6479 -- dereference made explicit in Analyze_Call.
6485 else
6486 -- Find the interpretation whose type (a subprogram type) has a
6487 -- return type that is compatible with the context. Analysis of
6488 -- the node has established that one exists.
6507 -- If the prefix is not an entity, then resolve it
6513 -- For an indirect call, we always invalidate checks, since we do not
6514 -- know whether the subprogram is local or global. Yes we could do
6515 -- better here, e.g. by knowing that there are no local subprograms,
6516 -- but it does not seem worth the effort. Similarly, we kill all
6517 -- knowledge of current constant values.
6519 Kill_Current_Values;
6521 -- If this is a procedure call which is really an entry call, do
6522 -- the conversion of the procedure call to an entry call. Protected
6523 -- operations use the same circuitry because the name in the call
6524 -- can be an arbitrary expression with special resolution rules.
6528 then
6535 -- Annotate the tree by creating a call marker in case the original
6536 -- call is transformed by expansion. The call marker is automatically
6537 -- saved for later examination by the ABE Processing phase.
6541 -- Kill checks and constant values, as above for indirect case
6542 -- Who knows what happens when another task is activated?
6544 Kill_Current_Values;
6547 -- Normal subprogram call with name established in Resolve
6553 -- Otherwise we must have the case of an overloaded call
6555 else
6558 -- Initialize Nam to prevent warning (we know it will be assigned
6559 -- in the loop below, but the compiler does not know that).
6575 -- Check that a call to Current_Task does not occur in an entry body
6578 declare
6581 begin
6583 loop
6586 -- Exclude calls that occur within the default of a formal
6587 -- parameter of the entry, since those are evaluated outside
6588 -- of the body.
6595 then
6598 Error_Msg_NE
6612 -- Check that a procedure call does not occur in the context of the
6613 -- entry call statement of a conditional or timed entry call. Note that
6614 -- the case of a call to a subprogram renaming of an entry will also be
6615 -- rejected. The test for N not being an N_Entry_Call_Statement is
6616 -- defensive, covering the possibility that the processing of entry
6617 -- calls might reach this point due to later modifications of the code
6618 -- above.
6623 then
6627 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6628 -- for a procedure_or_entry_call, the procedure_name or
6629 -- procedure_prefix of the procedure_call_statement shall denote
6630 -- an entry renamed by a procedure, or (a view of) a primitive
6631 -- subprogram of a limited interface whose first parameter is
6632 -- a controlling parameter.
6637 then
6638 Error_Msg_N
6643 -- Check that this is not a call to a protected procedure or entry from
6644 -- within a protected function.
6648 -- Freeze the subprogram name if not in a spec-expression. Note that
6649 -- we freeze procedure calls as well as function calls. Procedure calls
6650 -- are not frozen according to the rules (RM 13.14(14)) because it is
6651 -- impossible to have a procedure call to a non-frozen procedure in
6652 -- pure Ada, but in the code that we generate in the expander, this
6653 -- rule needs extending because we can generate procedure calls that
6654 -- need freezing.
6656 -- In Ada 2012, expression functions may be called within pre/post
6657 -- conditions of subsequent functions or expression functions. Such
6658 -- calls do not freeze when they appear within generated bodies,
6659 -- (including the body of another expression function) which would
6660 -- place the freeze node in the wrong scope. An expression function
6661 -- is frozen in the usual fashion, by the appearance of a real body,
6662 -- or at the end of a declarative part. However an implicit call to
6663 -- an expression function may appear when it is part of a default
6664 -- expression in a call to an initialization procedure, and must be
6665 -- frozen now, even if the body is inserted at a later point.
6666 -- Otherwise, the call freezes the expression if expander is active,
6667 -- for example as part of an object declaration.
6670 and then not In_Spec_Expression
6673 and then Is_Expression_Function_Or_Completion
6675 and then
6678 then
6681 -- Force freeze of expression function in call
6690 -- For a predefined operator, the type of the result is the type imposed
6691 -- by context, except for a predefined operation on universal fixed.
6692 -- Otherwise the type of the call is the type returned by the subprogram
6693 -- being called.
6700 -- If the subprogram returns an array type, and the context requires the
6701 -- component type of that array type, the node is really an indexing of
6702 -- the parameterless call. Resolve as such. A pathological case occurs
6703 -- when the type of the component is an access to the array type. In
6704 -- this case the call is truly ambiguous. If the call is to an intrinsic
6705 -- subprogram, it can't be an indexed component. This check is necessary
6706 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6707 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6708 -- pointers to the same array), the compiler gets confused and does an
6709 -- infinite recursion.
6712 and then
6715 or else
6718 and then
6721 then
6722 declare
6727 begin
6728 -- If this is a parameterless call there is no ambiguity and the
6729 -- call has the type of the function.
6738 -- Annotate the tree by creating a call marker in case the
6739 -- original call is transformed by expansion. The call marker
6740 -- is automatically saved for later examination by the ABE
6741 -- Processing phase.
6748 then
6749 Error_Msg_N
6751 else
6754 -- The called entity may be an explicit dereference, in which
6755 -- case there is no entity to set.
6763 or else
6765 and then
6767 then
6770 -- Indexed call to a parameterless function
6772 Index_Node :=
6774 Prefix =>
6777 else
6778 -- An Ada 2005 prefixed call to a primitive operation
6779 -- whose first parameter is the prefix. This prefix was
6780 -- prepended to the parameter list, which is actually a
6781 -- list of indexes. Remove the prefix in order to build
6782 -- the proper indexed component.
6784 Index_Node :=
6786 Prefix =>
6789 Parameter_Associations =>
6790 New_List
6795 -- Preserve the parenthesis count of the node
6799 -- Since we are correcting a node classification error made
6800 -- by the parser, we call Replace rather than Rewrite.
6811 -- Annotate the tree by creating a call marker in case
6812 -- the original call is transformed by expansion. The call
6813 -- marker is automatically saved for later examination by
6814 -- the ABE Processing phase.
6825 else
6826 -- If the called function is not declared in the main unit and it
6827 -- returns the limited view of type then use the available view (as
6828 -- is done in Try_Object_Operation) to prevent back-end confusion;
6829 -- for the function entity itself. The call must appear in a context
6830 -- where the nonlimited view is available. If the function entity is
6831 -- in the extended main unit then no action is needed, because the
6832 -- back end handles this case. In either case the type of the call
6833 -- is the nonlimited view.
6837 then
6844 else
6849 -- In the case where the call is to an overloaded subprogram, Analyze
6850 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6851 -- such a case Normalize_Actuals needs to be called once more to order
6852 -- the actuals correctly. Otherwise the call will have the ordering
6853 -- given by the last overloaded subprogram whether this is the correct
6854 -- one being called or not.
6861 -- In any case, call is fully resolved now. Reset Overload flag, to
6862 -- prevent subsequent overload resolution if node is analyzed again
6867 -- A Ghost entity must appear in a specific context
6874 Local_Restrict.Check_Call
6876 else
6880 -- If we are calling the current subprogram from immediately within its
6881 -- body, then that is the case where we can sometimes detect cases of
6882 -- infinite recursion statically. Do not try this in case restriction
6883 -- No_Recursion is in effect anyway, and do it only for source calls.
6888 -- Issue warning for possible infinite recursion in the absence
6889 -- of the No_Recursion restriction.
6895 then
6896 -- Here we detected and flagged an infinite recursion, so we do
6897 -- not need to test the case below for further warnings. Also we
6898 -- are all done if we now have a raise SE node.
6904 -- If call is to immediately containing subprogram, then check for
6905 -- the case of a possible run-time detectable infinite recursion.
6907 else
6911 -- Ada 2022 (AI12-0075): Static functions are never allowed
6912 -- to make a recursive call, as specified by 6.8(5.4/5).
6915 Error_Msg_N
6924 -- Although in general case, recursion is not statically
6925 -- checkable, the case of calling an immediately containing
6926 -- subprogram is easy to catch.
6932 -- If the recursive call is to a parameterless subprogram,
6933 -- then even if we can't statically detect infinite
6934 -- recursion, this is pretty suspicious, and we output a
6935 -- warning. Furthermore, we will try later to detect some
6936 -- cases here at run time by expanding checking code (see
6937 -- Detect_Infinite_Recursion in package Exp_Ch6).
6939 -- If the recursive call is within a handler, do not emit a
6940 -- warning, because this is a common idiom: loop until input
6941 -- is correct, catch illegal input in handler and restart.
6947 then
6948 -- For the case of a procedure call. We give the message
6949 -- only if the call is the first statement in a sequence
6950 -- of statements, or if all previous statements are
6951 -- simple assignments. This is simply a heuristic to
6952 -- decrease false positives, without losing too many good
6953 -- warnings. The idea is that these previous statements
6954 -- may affect global variables the procedure depends on.
6955 -- We also exclude raise statements, that may arise from
6956 -- constraint checks and are probably unrelated to the
6957 -- intended control flow.
6961 then
6962 declare
6964 begin
6968 | N_Raise_Constraint_Error
6969 then
6978 -- Do not give warning if we are in a conditional context
6980 declare
6982 begin
6988 then
6993 -- Here warning is to be issued
7009 -- Check obsolescent reference to Ada.Characters.Handling subprogram
7013 -- If subprogram name is a predefined operator, it was given in
7014 -- functional notation. Replace call node with operator node, so
7015 -- that actuals can be resolved appropriately.
7027 -- Create a transient scope if the expander is active and the resulting
7028 -- type requires it.
7030 -- There are several notable exceptions:
7032 -- a) Intrinsic subprograms (Unchecked_Conversion and source info
7033 -- functions) do not use the secondary stack even though the return
7034 -- type may be unconstrained.
7036 -- b) Subprograms that are ignored ghost entities do not return anything
7038 -- c) Calls to a build-in-place function, since such functions may
7039 -- allocate their result directly in a target object, and cases where
7040 -- the result does get allocated in the secondary stack are checked for
7041 -- within the specialized Exp_Ch6 procedures for expanding those
7042 -- build-in-place calls.
7044 -- d) Calls to inlinable expression functions do not use the secondary
7045 -- stack (since the call will be replaced by its returned object).
7047 -- e) If the subprogram is marked Inline, then even if it returns
7048 -- an unconstrained type the call does not require use of the secondary
7049 -- stack. However, inlining will only take place if the body to inline
7050 -- is already present. It may not be available if e.g. the subprogram is
7051 -- declared in a child instance.
7053 -- f) If the subprogram is a static expression function and the call is
7054 -- a static call (the actuals are all static expressions), then we never
7055 -- want to create a transient scope (this could occur in the case of a
7056 -- static string-returning call).
7058 -- g) If the call is the expression of a simple return statement that
7059 -- returns on the same stack, since it will be handled as a tail call
7060 -- by Expand_Simple_Function_Return.
7062 if Expander_Active
7072 N_Subprogram_Declaration
7073 and then
7077 and then
7078 Needs_Secondary_Stack
7079 (Etype
7080 (Return_Applies_To
7083 then
7086 -- If the call appears within the bounds of a loop, it will be
7087 -- rewritten and reanalyzed, nothing left to do here.
7094 -- A protected function cannot be called within the definition of the
7095 -- enclosing protected type, unless it is part of a pre/postcondition
7096 -- on another protected operation. This may appear in the entry wrapper
7097 -- created for an entry with preconditions.
7102 and then not In_Spec_Expression
7104 then
7105 Error_Msg_NE
7109 -- Propagate interpretation to actuals, and add default expressions
7110 -- where needed.
7115 -- Overloaded literals are rewritten as function calls, for purpose of
7116 -- resolution. After resolution, we can replace the call with the
7117 -- literal itself.
7123 -- Avoid validation, since it is a static function call
7129 -- If the subprogram is not global, then kill all saved values and
7130 -- checks. This is a bit conservative, since in many cases we could do
7131 -- better, but it is not worth the effort. Similarly, we kill constant
7132 -- values. However we do not need to do this for internal entities
7133 -- (unless they are inherited user-defined subprograms), since they
7134 -- are not in the business of molesting local values.
7136 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
7137 -- kill all checks and values for calls to global subprograms. This
7138 -- takes care of the case where an access to a local subprogram is
7139 -- taken, and could be passed directly or indirectly and then called
7140 -- from almost any context.
7142 -- Note: we do not do this step till after resolving the actuals. That
7143 -- way we still take advantage of the current value information while
7144 -- scanning the actuals.
7146 -- We suppress killing values if we are processing the nodes associated
7147 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
7148 -- type kills all the values as part of analyzing the code that
7149 -- initializes the dispatch tables.
7153 or else Suppress_Value_Tracking_On_Call
7158 then
7159 Kill_Current_Values;
7162 -- If we are warning about unread OUT parameters, this is the place to
7163 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7164 -- after the above call to Kill_Current_Values (since that call clears
7165 -- the Last_Assignment field of all local variables).
7170 then
7171 declare
7175 begin
7185 then
7195 -- If the subprogram is a primitive operation, check whether or not
7196 -- it is a correct dispatching call.
7201 -- If the subprogram is an abstract operation, then flag an error
7207 -- If this is a dispatching call, generate the appropriate reference,
7208 -- for better source navigation in GNAT Studio.
7213 -- Normal case, not a dispatching call: generate a call reference
7215 else
7223 -- Check for violation of restriction No_Specific_Termination_Handlers
7224 -- and warn on a potentially blocking call to Abort_Task.
7228 or else
7230 then
7237 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7238 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7239 -- need to check the second argument to determine whether it is an
7240 -- absolute or relative timing event.
7245 then
7249 -- Issue an error for a call to an eliminated subprogram. This routine
7250 -- will not perform the check if the call appears within a default
7251 -- expression.
7255 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7256 -- class-wide and the call dispatches on result in a context that does
7257 -- not provide a tag, the call raises Program_Error.
7260 and then In_Instance
7265 then
7266 -- Verify that none of the formals are controlling
7268 declare
7272 begin
7294 -- Check for calling a function with OUT or IN OUT parameter when the
7295 -- calling context (us right now) is not Ada 2012, so does not allow
7296 -- OUT or IN OUT parameters in function calls. Functions declared in
7297 -- a predefined unit are OK, as they may be called indirectly from a
7298 -- user-declared instantiation.
7304 then
7309 -- Check the dimensions of the actuals in the call. For function calls,
7310 -- propagate the dimensions from the returned type to N.
7314 -- Check unreachable code after calls to procedures with No_Return
7320 -- All done, evaluate call and deal with elaboration issues
7328 -- Annotate the tree by creating a call marker in case the original call
7329 -- is transformed by expansion. The call marker is automatically saved
7330 -- for later examination by the ABE Processing phase.
7338 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7339 -- expression function, then we want to "inline" the call, replacing
7340 -- it with the folded static result. This is not done if the checking
7341 -- for a potentially static expression is enabled or if an error has
7342 -- been posted on the call (which may be due to the check for recursive
7343 -- calls, in which case we don't want to fall into infinite recursion
7344 -- when doing the inlining).
7346 if not Checking_Potentially_Static_Expression
7350 then
7353 -- In GNATprove mode, expansion is disabled, but we want to inline some
7354 -- subprograms to facilitate formal verification. Indirect calls through
7355 -- a subprogram type or within a generic cannot be inlined. Inlining is
7356 -- performed only for calls subject to SPARK_Mode => On.
7358 elsif GNATprove_Mode
7361 and then not Inside_A_Generic
7362 then
7369 -- Nothing to do if the subprogram is not inlined (because it is
7370 -- recursive, directly or indirectly), or is not eligible for
7371 -- inlining GNATprove mode (because of properties of the
7372 -- subprogram itself), or inlining has been disabled with switch
7373 -- -gnatdm.
7377 or else Debug_Flag_M
7378 then
7381 -- Calls cannot be inlined inside assertions, as GNATprove treats
7382 -- assertions as logic expressions. Only issue a message when the
7383 -- body has been seen, otherwise this leads to spurious messages
7384 -- on expression functions.
7387 Cannot_Inline
7391 -- Calls cannot be inlined inside default expressions
7394 Cannot_Inline
7397 -- Calls cannot be inlined inside potentially unevaluated
7398 -- expressions, as this would create complex actions inside
7399 -- expressions, that are not handled by GNATprove.
7402 Cannot_Inline
7406 -- Calls are not inlined inside the loop_parameter_specification
7407 -- or iterator_specification of the quantified expression, as they
7408 -- are only preanalyzed. Calls in the predicate part are handled
7409 -- by the previous test on potentially unevaluated expressions.
7412 Cannot_Inline
7415 -- Inlining should not be performed during preanalysis
7419 -- Do not inline calls inside expression functions or functions
7420 -- generated by the front end for subtype predicates, as this
7421 -- would prevent interpreting them as logical formulas in
7422 -- GNATprove. Only issue a message when the body has been seen,
7423 -- otherwise this leads to spurious messages on callees that
7424 -- are themselves expression functions.
7427 and then
7432 then
7433 declare
7437 begin
7439 Cannot_Inline
7444 Cannot_Inline
7449 Cannot_Inline
7453 else
7454 Cannot_Inline
7460 -- Cannot inline a call inside the definition of a record type,
7461 -- typically inside the constraints of the type. Calls in
7462 -- default expressions are also not inlined, but this is
7463 -- filtered out above when testing In_Default_Expr.
7466 Cannot_Inline
7469 -- With the one-pass inlining technique, a call cannot be
7470 -- inlined if the corresponding body has not been seen yet.
7473 Cannot_Inline
7476 -- Nothing to do if there is no body to inline, indicating that
7477 -- the subprogram is not suitable for inlining in GNATprove
7478 -- mode.
7483 -- Calls cannot be inlined inside the conditions of while
7484 -- loops, as this would create complex actions inside
7485 -- the condition, that are not handled by GNATprove.
7488 Cannot_Inline
7491 -- Do not inline calls which would possibly lead to missing a
7492 -- type conversion check on an input parameter or a memory leak
7493 -- on an output parameter.
7496 Cannot_Inline
7500 -- Otherwise, inline the call, issuing an info message when
7501 -- -gnatd_f is set.
7503 else
7505 Error_Msg_NE
7516 -----------------------------
7517 -- Resolve_Case_Expression --
7518 -----------------------------
7526 begin
7540 -- When the expression is of a scalar subtype different from the
7541 -- result subtype, then insert a conversion to ensure the generation
7542 -- of a constraint check.
7555 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7556 -- dynamically tagged must be known statically.
7564 Error_Msg_N
7578 -------------------------------
7579 -- Resolve_Character_Literal --
7580 -------------------------------
7586 begin
7587 -- Verify that the character does belong to the type of the context
7592 -- Wide_Wide_Character literals must always be defined, since the set
7593 -- of wide wide character literals is complete, i.e. if a character
7594 -- literal is accepted by the parser, then it is OK for wide wide
7595 -- character (out of range character literals are rejected).
7600 -- Always accept character literal for type Any_Character, which
7601 -- occurs in error situations and in comparisons of literals, both
7602 -- of which should accept all literals.
7607 -- For Standard.Character or a type derived from it, check that the
7608 -- literal is in range.
7615 -- For Standard.Wide_Character or a type derived from it, check that the
7616 -- literal is in range.
7623 -- If the entity is already set, this has already been resolved in a
7624 -- generic context, or comes from expansion. Nothing else to do.
7629 -- Otherwise we have a user defined character type, and we can use the
7630 -- standard visibility mechanisms to locate the referenced entity.
7632 else
7645 -- If we fall through, then the literal does not match any of the
7646 -- entries of the enumeration type. This isn't just a constraint error
7647 -- situation, it is an illegality (see RM 4.2).
7649 Error_Msg_NE
7653 ---------------------------
7654 -- Resolve_Comparison_Op --
7655 ---------------------------
7657 -- The operands must have compatible types and the boolean context does not
7658 -- participate in the resolution. The first pass verifies that the operands
7659 -- are not ambiguous and sets their type correctly, or to Any_Type in case
7660 -- of ambiguity. If both operands are strings or aggregates, then they are
7661 -- ambiguous even if they carry a single (universal) type.
7669 begin
7678 -- Deal with explicit ambiguity of operands
7687 -- Deal with other error cases
7691 T = Any_Character
7692 then
7695 else
7703 -- Resolve the operands if types OK
7713 -- Check comparison on unordered enumeration
7717 Error_Msg_NE
7727 --------------------------------
7728 -- Resolve_Declare_Expression --
7729 --------------------------------
7731 procedure Resolve_Declare_Expression
7734 is
7741 -- Use a tree traversal to replace each occurrence of the name of
7742 -- a local object declared in the construct, with the corresponding
7743 -- entity. This replaces the usual way to perform name capture by
7744 -- visibility, because it is not possible to place on the scope
7745 -- stack the fake scope created for the analysis of the local
7746 -- declarations; such a scope conflicts with the transient scopes
7747 -- that may be generated if the expression includes function calls
7748 -- requiring finalization.
7750 -------------------
7751 -- Replace_Local --
7752 -------------------
7755 begin
7756 -- The identifier may be the prefix of a selected component,
7757 -- but not a selector name, because the local entities do not
7758 -- have a scope that can be named: a selected component whose
7759 -- selector is a homonym of a local entity must denote some
7760 -- global entity.
7765 and then
7768 then
7778 -- Start of processing for Resolve_Declare_Expression
7780 begin
7785 N_Object_Declaration | N_Object_Renaming_Declaration
7787 then
7791 -- Traverse the expression to replace references to local
7792 -- variables that occur within declarations of the
7793 -- declare_expression.
7795 declare
7797 begin
7808 -- The end of the declarative list is a freeze point for the
7809 -- local declarations.
7820 -----------------------------------
7821 -- Resolve_Dependent_Expression --
7822 -----------------------------------
7824 procedure Resolve_Dependent_Expression
7828 is
7829 begin
7830 -- RM 4.5.7(8/3) says that the expected type of dependent expressions is
7831 -- that of the conditional expression but RM 4.5.7(10/3) forces the type
7832 -- of the conditional expression without changing the expected type (the
7833 -- expected type of the operand of a type conversion is any type), so we
7834 -- may have a gap between these two types that is bridged by the dynamic
7835 -- semantics specified by RM 4.5.7(20/3) with the associated legality
7836 -- rule RM 4.5.7(16/3) that will be automatically enforced.
7840 then
7843 else
7848 -----------------------------------------
7849 -- Resolve_Discrete_Subtype_Indication --
7850 -----------------------------------------
7852 procedure Resolve_Discrete_Subtype_Indication
7855 is
7859 begin
7867 else
7877 Error_Msg_NE
7880 -- Rewrite the constraint as a range of Typ
7881 -- to allow compilation to proceed further.
7893 else
7897 -- Additionally, we must check that the bounds are compatible
7898 -- with the given subtype, which might be different from the
7899 -- type of the context.
7903 -- ??? If the above check statically detects a Constraint_Error
7904 -- it replaces the offending bound(s) of the range R with a
7905 -- Constraint_Error node. When the itype which uses these bounds
7906 -- is frozen the resulting call to Duplicate_Subexpr generates
7907 -- a new temporary for the bounds.
7909 -- Unfortunately there are other itypes that are also made depend
7910 -- on these bounds, so when Duplicate_Subexpr is called they get
7911 -- a forward reference to the newly created temporaries and Gigi
7912 -- aborts on such forward references. This is probably sign of a
7913 -- more fundamental problem somewhere else in either the order of
7914 -- itype freezing or the way certain itypes are constructed.
7916 -- To get around this problem we call Remove_Side_Effects right
7917 -- away if either bounds of R are a Constraint_Error.
7919 declare
7923 begin
7939 -------------------------
7940 -- Resolve_Entity_Name --
7941 -------------------------
7943 -- Used to resolve identifiers and expanded names
7946 function Is_Assignment_Or_Object_Expression
7949 -- Determine whether node Context denotes an assignment statement or an
7950 -- object declaration whose expression is node Expr.
7953 -- Determine whether Expr is part of an N_Attribute_Reference
7954 -- expression.
7956 ----------------------------------------
7957 -- Is_Assignment_Or_Object_Expression --
7958 ----------------------------------------
7960 function Is_Assignment_Or_Object_Expression
7963 is
7964 begin
7967 then
7970 -- Check whether a construct that yields a name is the expression of
7971 -- an assignment statement or an object declaration.
7974 | N_Explicit_Dereference
7975 | N_Indexed_Component
7976 | N_Selected_Component
7977 | N_Slice
7979 or else
7981 | N_Unchecked_Type_Conversion
7983 then
7984 return
7985 Is_Assignment_Or_Object_Expression
7989 -- Otherwise the context is not an assignment statement or an object
7990 -- declaration.
7992 else
7997 -----------------------------
7998 -- Is_Attribute_Expression --
7999 -----------------------------
8003 begin
8008 -- Prevent the search from going too far
8020 -- Local variables
8025 -- Start of processing for Resolve_Entity_Name
8027 begin
8028 -- If garbage from errors, set to Any_Type and return
8035 -- Replace named numbers by corresponding literals. Note that this is
8036 -- the one case where Resolve_Entity_Name must reset the Etype, since
8037 -- it is currently marked as universal.
8047 -- For enumeration literals, we need to make sure that a proper style
8048 -- check is done, since such literals are overloaded, and thus we did
8049 -- not do a style check during the first phase of analysis.
8055 -- Case of (sub)type name appearing in a context where an expression
8056 -- is expected. This is legal if occurrence is a current instance.
8057 -- See RM 8.6 (17/3). It is also legal if the expression is
8058 -- part of a choice pattern for a case stmt/expr having a
8059 -- non-discrete selecting expression.
8065 -- Any other use is an error
8067 else
8068 Error_Msg_N
8072 -- Check discriminant use if entity is discriminant in current scope,
8073 -- i.e. discriminant of record or concurrent type currently being
8074 -- analyzed. Uses in corresponding body are unrestricted.
8079 then
8082 -- A parameterless generic function cannot appear in a context that
8083 -- requires resolution.
8088 -- In Ada 83 an OUT parameter cannot be read, but attributes of
8089 -- array types (i.e. bounds and length) are legal.
8097 or else Is_Assignment_Or_Object_Expression
8100 then
8105 -- In all other cases, just do the possible static evaluation
8107 else
8108 -- A deferred constant that appears in an expression must have a
8109 -- completion, unless it has been removed by in-place expansion of
8110 -- an aggregate. A constant that is a renaming does not need
8111 -- initialization.
8117 and then not In_Spec_Expression
8120 then
8124 then
8126 else
8127 Error_Msg_N
8137 -- When the entity appears in a parameter association, retrieve the
8138 -- related subprogram call.
8146 -- The following checks are only relevant when SPARK_Mode is On as
8147 -- they are not standard Ada legality rules.
8151 -- Check for possible elaboration issues with respect to reads of
8152 -- variables. The act of renaming the variable is not considered a
8153 -- read as it simply establishes an alias.
8155 if Legacy_Elaboration_Checks
8157 and then Dynamic_Elaboration_Checks
8159 then
8164 -- The variable may eventually become a constituent of a single
8165 -- protected/task type. Record the reference now and verify its
8166 -- legality when analyzing the contract of the variable
8167 -- (SPARK RM 9.3).
8173 -- A Ghost entity must appear in a specific context
8179 -- We may be resolving an entity within expanded code, so a reference
8180 -- to an entity should be ignored when calculating effective use
8181 -- clauses to avoid inappropriate marking.
8187 -------------------
8188 -- Resolve_Entry --
8189 -------------------
8201 -- If the bounds of the entry family being called depend on task
8202 -- discriminants, build a new index subtype where a discriminant is
8203 -- replaced with the value of the discriminant of the target task.
8204 -- The target task is the prefix of the entry name in the call.
8206 -----------------------
8207 -- Actual_Index_Type --
8208 -----------------------
8218 -- If the bound is given by a discriminant, replace with a reference
8219 -- to the discriminant of the same name in the target task. If the
8220 -- entry name is the target of a requeue statement and the entry is
8221 -- in the current protected object, the bound to be used is the
8222 -- discriminal of the object (see Apply_Range_Check for details of
8223 -- the transformation).
8225 -----------------------------
8226 -- Actual_Discriminant_Ref --
8227 -----------------------------
8233 begin
8238 then
8244 then
8245 -- Note: here Bound denotes a discriminant of the corresponding
8246 -- record type tskV, whose discriminal is a formal of the
8247 -- init-proc tskVIP. What we want is the body discriminal,
8248 -- which is associated to the discriminant of the original
8249 -- concurrent type tsk.
8251 return New_Occurrence_Of
8254 else
8255 Ref :=
8265 -- Start of processing for Actual_Index_Type
8267 begin
8270 then
8273 else
8287 -- Start of processing for Resolve_Entry
8289 begin
8290 -- Find name of entry being called, and resolve prefix of name with its
8291 -- own type. The prefix can be overloaded, and the name and signature of
8292 -- the entry must be taken into account.
8296 -- Case of dealing with entry family within the current tasks
8300 else
8306 -- Entry call to an entry (or entry family) in the current task. This
8307 -- is legal even though the task will deadlock. Rewrite as call to
8308 -- current task.
8310 -- This can also be a call to an entry in an enclosing task. If this
8311 -- is a single task, we have to retrieve its name, because the scope
8312 -- of the entry is the task type, not the object. If the enclosing
8313 -- task is a task type, the identity of the task is given by its own
8314 -- self variable.
8316 -- Finally this can be a requeue on an entry of the same task or
8317 -- protected object.
8324 then
8325 -- S is an enclosing task or protected object. The concurrent
8326 -- declaration has been converted into a type declaration, and
8327 -- the object itself has an object declaration that follows
8328 -- the type in the same declarative part.
8340 -- Call to current task. Will be transformed into call to Self
8347 New_N :=
8350 Selector_Name =>
8357 then
8358 -- Use the entry name (which must be unique at this point) to find
8359 -- the prefix that returns the corresponding task/protected type.
8361 declare
8367 begin
8389 -- We do not resolve the prefix because an Entry_Family has no type,
8390 -- although it has the semantics of an array since it can be indexed.
8391 -- In order to perform the associated range check, we would need to
8392 -- build an array type on the fly and set it on the prefix, but this
8393 -- would be wasteful since only the index type matters. Therefore we
8394 -- attach this index type directly, so that Actual_Index_Expression
8395 -- can pick it up later in order to generate the range check.
8402 -- Generate a reference for the index when it denotes an entity
8408 -- Up to this point the expression could have been the actual in a
8409 -- simple entry call, and be given by a named association.
8413 else
8419 ------------------------
8420 -- Resolve_Entry_Call --
8421 ------------------------
8432 begin
8433 -- We kill all checks here, because it does not seem worth the effort to
8434 -- do anything better, an entry call is a big operation.
8436 Kill_All_Checks;
8438 -- Processing of the name is similar for entry calls and protected
8439 -- operation calls. Once the entity is determined, we can complete
8440 -- the resolution of the actuals.
8442 -- The selector may be overloaded, in the case of a protected object
8443 -- with overloaded functions. The type of the context is used for
8444 -- resolution.
8449 then
8450 declare
8454 begin
8473 -- Simple entry or protected operation call
8486 -- Call to member of entry family
8493 -- We cannot in general check the maximum depth of protected entry calls
8494 -- at compile time. But we can tell that any protected entry call at all
8495 -- violates a specified nesting depth of zero.
8501 -- Use context type to disambiguate a protected function that can be
8502 -- called without actuals and that returns an array type, and where the
8503 -- argument list may be an indexing of the returned value.
8508 and then
8514 and then
8515 Covers
8518 then
8519 declare
8522 begin
8523 Index_Node :=
8525 Prefix =>
8529 -- Since we are correcting a node classification error made by the
8530 -- parser, we call Replace rather than Rewrite.
8544 then
8545 -- Note the entity being called before rewriting the call, so that
8546 -- it appears used at this point.
8550 -- Rewrite as call to the precondition wrapper, adding the task
8551 -- object to the list of actuals. If the call is to a member of an
8552 -- entry family, include the index as well.
8554 declare
8558 begin
8567 New_Call :=
8569 Name =>
8574 -- Preanalyze and resolve new call. Current procedure is called
8575 -- from Resolve_Call, after which expansion will take place.
8582 -- The operation name may have been overloaded. Order the actuals
8583 -- according to the formals of the resolved entity, and set the return
8584 -- type to that of the operation.
8591 -- Reset the Is_Overloaded flag, since resolution is now completed
8593 -- Simple entry call
8598 -- Call to a member of an entry family
8608 -- Create a call reference to the entry
8616 -- Verify that a procedure call cannot masquerade as an entry
8617 -- call where an entry call is expected.
8622 then
8627 then
8632 then
8637 -- After resolution, entry calls and protected procedure calls are
8638 -- changed into entry calls, for expansion. The structure of the node
8639 -- does not change, so it can safely be done in place. Protected
8640 -- function calls must keep their structure because they are
8641 -- subexpressions.
8645 -- A protected operation that is not a function may modify the
8646 -- corresponding object, and cannot apply to a constant. If this
8647 -- is an internal call, the prefix is the type itself.
8653 then
8654 Error_Msg_N
8656 Entry_Name);
8659 declare
8662 begin
8663 Entry_Call :=
8668 -- Inherit relevant attributes from the original call
8670 Set_First_Named_Actual
8673 Set_Is_Elaboration_Checks_OK_Node
8676 Set_Is_Elaboration_Warnings_OK_Node
8679 Set_Is_SPARK_Mode_On_Node
8686 -- Protected functions can return on the secondary stack, in which case
8687 -- we must trigger the transient scope mechanism.
8689 elsif Expander_Active
8691 then
8695 -- Now we know that this is not a call to a function that returns an
8696 -- array type; moreover, we know the name of the called entry. Detect
8697 -- overlapping actuals, just like for a subprogram call.
8702 -------------------------
8703 -- Resolve_Equality_Op --
8704 -------------------------
8706 -- The operands must have compatible types and the boolean context does not
8707 -- participate in the resolution. The first pass verifies that the operands
8708 -- are not ambiguous and sets their type correctly, or to Any_Type in case
8709 -- of ambiguity. If both operands are strings, aggregates, allocators, or
8710 -- null, they are ambiguous even if they carry a single (universal) type.
8720 and then not
8722 -- Whether this is a call to the implicit inequality operator created
8723 -- for a user-defined operator that is not an intrinsic subprogram, in
8724 -- which case we need to skip some processing.
8729 -- For any object, '[Unchecked_]Access of such object can never be
8730 -- passed as an operand to the Universal_Access equality operators.
8731 -- This is so because the expected type for Obj'Access in a call to
8732 -- these operators, whose formals are of type Universal_Access, is
8733 -- Universal_Access, and Universal_Access does not have a designated
8734 -- type. For more details, see RM 3.10.2(2/2) and 6.4.1(3).
8737 -- Check RM 4.5.2(9.6/2) on the given designated object types
8740 -- Check RM 4.5.2(9.7/2) on the given designated subprogram types
8743 -- The resolution rule for if expressions requires that each such must
8744 -- have a unique type. This means that if several dependent expressions
8745 -- are of a non-null anonymous access type, and the context does not
8746 -- impose an expected type (as can be the case in an equality operation)
8747 -- the expression must be rejected.
8750 -- Attempt to explain the nature of a redundant comparison with True. If
8751 -- the expression N is too complex, this routine issues a general error
8752 -- message.
8755 -- In the case of allocators and access attributes, the context must
8756 -- provide an indication of the specific access type to be used. If
8757 -- one operand is of such a "generic" access type, check whether there
8758 -- is a specific visible access type that has the same designated type.
8759 -- This is semantically dubious, and of no interest to any real code,
8760 -- but c48008a makes it all worthwhile.
8763 -- Returns True iff the parent node is a and/or/xor operation that
8764 -- could be the cause of confused priorities. Note that if the not is
8765 -- in parens, then False is returned.
8767 ----------------------------
8768 -- Check_Access_Attribute --
8769 ----------------------------
8772 begin
8775 then
8776 Error_Msg_N
8782 -----------------------------------
8783 -- Check_Designated_Object_Types --
8784 -----------------------------------
8787 begin
8791 then
8792 Error_Msg_N
8800 ---------------------------------------
8801 -- Check_Designated_Subprogram_Types --
8802 ---------------------------------------
8805 begin
8807 Error_Msg_N
8815 -------------------------
8816 -- Check_If_Expression --
8817 -------------------------
8823 begin
8830 then
8836 ------------------------
8837 -- Explain_Redundancy --
8838 ------------------------
8845 begin
8848 -- Strip the operand down to an entity
8850 loop
8853 else
8858 -- The construct denotes an entity
8863 -- Do not generate an error message when the comparison is done
8864 -- against the enumeration literal Standard.True.
8868 -- Build a customized error message
8895 -- The construct is too complex to disect, issue a general message
8897 else
8902 -----------------------------
8903 -- Find_Unique_Access_Type --
8904 -----------------------------
8911 begin
8913 then
8917 then
8919 else
8931 then
8944 ----------------------------------
8945 -- Suspicious_Prio_For_Equality --
8946 ----------------------------------
8951 begin
8952 -- Check if parent node is one of and/or/xor, not parenthesized
8953 -- explicitly, and its own parent is not of this kind. Otherwise,
8954 -- it's a case of chained Boolean conditions which is likely well
8955 -- parenthesized.
8960 then
8961 declare
8965 else
8967 begin
8968 -- Compar may have been rewritten, for example from (a /= b)
8969 -- into not (a = b). Use the Original_Node instead.
8973 -- If the other argument of the and/or/xor is also a
8974 -- comparison, or another and/or/xor then most likely
8975 -- the priorities are correctly set.
8980 else
8985 -- Start of processing for Resolve_Equality_Op
8987 begin
8996 -- Deal with explicit ambiguity of operands, unless this is a call
8997 -- to the implicit inequality operator created for a user-defined
8998 -- operator that is not an intrinsic subprogram, since the common
8999 -- resolution of operands done here does not apply to it.
9001 if not Implicit_NE_For_User_Defined_Operator
9003 then
9007 else
9009 -- For Ada 2022, check for user-defined literals when the type has
9010 -- the appropriate aspect.
9022 -- Deal with other error cases
9026 T = Any_Character
9027 then
9030 else
9039 then
9048 -- If expressions must have a single type, and if the context does
9049 -- not impose one the dependent expressions cannot be anonymous
9050 -- access types.
9052 -- Why no similar processing for case expressions???
9057 then
9062 -- RM 4.5.2(9.5/2): At least one of the operands of the equality
9063 -- operators for universal_access shall be of type universal_access,
9064 -- or both shall be of access-to-object types, or both shall be of
9065 -- access-to-subprogram types (RM 4.5.2(9.5/2)).
9070 then
9071 -- RM 4.5.2(9.6/2): When both are of access-to-object types, the
9072 -- designated types shall be the same or one shall cover the other
9073 -- and if the designated types are elementary or array types, then
9074 -- the designated subtypes shall statically match.
9078 then
9079 Check_Designated_Object_Types
9082 -- RM 4.5.2(9.7/2): When both are of access-to-subprogram types,
9083 -- the designated profiles shall be subtype conformant.
9087 then
9088 Check_Designated_Subprogram_Types
9093 -- Check another case of equality operators for universal_access
9104 -- AI12-0413: user-defined primitive equality of an untagged record
9105 -- type hides the predefined equality operator, including within a
9106 -- generic, and if it is declared abstract, results in an illegal
9107 -- instance if the operator is used in the spec, or in the raising
9108 -- of Program_Error if used in the body of an instance.
9111 and then In_Instance
9113 then
9114 declare
9119 begin
9123 then
9129 else
9139 -- If the unique type is a class-wide type then it will be expanded
9140 -- into a dispatching call to the predefined primitive. Therefore we
9141 -- check here for potential violation of such restriction.
9147 -- Only warn for redundant equality comparison to True for objects
9148 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
9149 -- other expressions, it may be a matter of preference to write
9150 -- "Expr = True" or "Expr".
9152 if Warn_On_Redundant_Constructs
9157 and then
9159 or else
9161 then
9162 Error_Msg_N -- CODEFIX
9167 -- Warn on a (in)equality between boolean values which is not
9168 -- parenthesized when the parent expression is one of and/or/xor, as
9169 -- this is interpreted as (a = b) op c where most likely a = (b op c)
9170 -- was intended. Do not generate a warning in generic instances, as
9171 -- the problematic expression may be implicitly parenthesized in
9172 -- the generic itself if one of the operators is a generic formal.
9173 -- Also do not generate a warning for generated equality, for
9174 -- example from rewritting a membership test.
9176 if Warn_On_Questionable_Missing_Parens
9177 and then not In_Instance
9180 and then Suspicious_Prio_For_Equality
9181 then
9190 -- Unless this is a call to the implicit inequality operator created
9191 -- for a user-defined operator that is not an intrinsic subprogram,
9192 -- try to fold the operation.
9200 then
9206 ----------------------------------
9207 -- Resolve_Explicit_Dereference --
9208 ----------------------------------
9216 -- The candidate prefix type, if overloaded
9221 begin
9225 -- A useful optimization: check whether the dereference denotes an
9226 -- element of a container, and if so rewrite it as a call to the
9227 -- corresponding Element function.
9229 -- Disabled for now, on advice of ARG. A more restricted form of the
9230 -- predicate might be acceptable ???
9232 -- if Is_Container_Element (N) then
9233 -- return;
9234 -- end if;
9238 -- Use the context type to select the prefix that has the correct
9239 -- designated type. Keep the first match, which will be the inner-
9240 -- most.
9247 then
9252 -- Remove access types that do not match, but preserve access
9253 -- to subprogram interpretations, in case a further dereference
9254 -- is needed (see below).
9267 else
9268 -- If no interpretation covers the designated type of the prefix,
9269 -- this is the pathological case where not all implementations of
9270 -- the prefix allow the interpretation of the node as a call. Now
9271 -- that the expected type is known, Remove other interpretations
9272 -- from prefix, rewrite it as a call, and resolve again, so that
9273 -- the proper call node is generated.
9284 New_N :=
9286 Name =>
9297 -- If not overloaded, resolve P with its own type
9299 else
9303 -- If the prefix might be null, add an access check
9307 then
9311 -- If the designated type is a packed unconstrained array type, and the
9312 -- explicit dereference is not in the context of an attribute reference,
9313 -- then we must compute and set the actual subtype, since it is needed
9314 -- by Gigi. The reason we exclude the attribute case is that this is
9315 -- handled fine by Gigi, and in fact we use such attributes to build the
9316 -- actual subtype. We also exclude generated code (which builds actual
9317 -- subtypes directly if they are needed).
9323 then
9329 -- Note: No Eval processing is required for an explicit dereference,
9330 -- because such a name can never be static.
9334 -------------------------------------
9335 -- Resolve_Expression_With_Actions --
9336 -------------------------------------
9341 -- True if Act is an action of a declare_expression that is allowed in a
9342 -- static declare_expression.
9345 -- True if all actions of N are allowed in a static declare_expression.
9348 -- Expr is an expression with compile-time-known value. This returns the
9349 -- literal node that reprsents that value.
9351 -------------------
9352 -- OK_For_Static --
9353 -------------------
9356 begin
9361 then
9371 -- No other declarations, nor even pragmas, are allowed in a
9372 -- declare expression, so if we see something else, it must be
9373 -- an internally generated expression_with_actions.
9380 -----------------------
9381 -- All_OK_For_Static --
9382 -----------------------
9386 begin
9398 -----------------
9399 -- Get_Literal --
9400 -----------------
9405 begin
9410 else
9419 pragma Assert
9425 -- Local variables
9429 -- Start of processing for Resolve_Expression_With_Actions
9431 begin
9438 -- If the value of the expression is known at compile time, and all
9439 -- of the actions (if any) are suitable, then replace the declare
9440 -- expression with its expression. This allows the declare expression
9441 -- as a whole to be static if appropriate. See AI12-0368.
9447 Rewrite
9454 ----------------------------------
9455 -- Resolve_External_Initializer --
9456 ----------------------------------
9459 begin
9463 ----------------------------------
9464 -- Resolve_Generalized_Indexing --
9465 ----------------------------------
9469 begin
9474 ---------------------------
9475 -- Resolve_If_Expression --
9476 ---------------------------
9482 -- When a dependent expression is of a subtype different from
9483 -- the context subtype, then insert a qualification to ensure
9484 -- the generation of a constraint check. This was previously
9485 -- for scalar types. For array types apply a length check, given
9486 -- that the context in general allows sliding, while a qualified
9487 -- expression forces equality of bounds.
9489 -----------------
9490 -- Apply_Check --
9491 -----------------
9497 begin
9502 or else Inside_A_Generic
9503 then
9509 else
9519 -- Local variables
9525 -- So in most cases the type of the if_expression and of its
9526 -- dependent expressions is that of the context. However, if
9527 -- the expression is the index of an Indexed_Component, we must
9528 -- ensure that a proper index check is applied, rather than a
9529 -- range check on the index type (which might be discriminant
9530 -- dependent). In this case we resolve with the base type of the
9531 -- index type, and the index check is generated in the resolution
9532 -- of the indexed_component above.
9534 -- Start of processing for Resolve_If_Expression
9536 begin
9537 -- Defend against malformed expressions
9546 then
9549 else
9569 -- If ELSE expression present, just resolve using the determined type
9577 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9578 -- dynamically tagged must be known statically.
9583 then
9589 -- If no ELSE expression is present, root type must be Standard.Boolean
9590 -- and we provide a Standard.True result converted to the appropriate
9591 -- Boolean type (in case it is a derived boolean type).
9594 Else_Expr :=
9599 else
9613 ----------------------------------
9614 -- Resolve_Implicit_Dereference --
9615 ----------------------------------
9620 begin
9628 -------------------------------
9629 -- Resolve_Indexed_Component --
9630 -------------------------------
9638 begin
9646 -- Use the context type to select the prefix that yields the correct
9647 -- component type.
9649 declare
9655 begin
9662 and then
9663 Covers
9666 then
9675 else
9681 else
9692 else
9699 -- If the prefix's type is an access type, get to the real array type.
9700 -- Note: we do not apply an access check because an explicit dereference
9701 -- will be introduced later, and the check will happen there.
9707 -- If name was overloaded, set component type correctly now.
9708 -- If a misplaced call to an entry family (which has no index types)
9709 -- return. Error will be diagnosed from calling context.
9713 else
9720 -- The prefix may have resolved to a string literal, in which case its
9721 -- etype has a special representation. This is only possible currently
9722 -- if the prefix is a static concatenation, written in functional
9723 -- notation.
9728 else
9743 -- Do not generate the warning on suspicious index if we are analyzing
9744 -- package Ada.Tags; otherwise we will report the warning with the
9745 -- Prims_Ptr field of the dispatch table.
9748 or else not
9750 then
9755 -- If the array type is atomic and the component is not, then this is
9756 -- worth a warning before Ada 2022, since we have a situation where the
9757 -- access to the component may cause extra read/writes of the atomic
9758 -- object, or partial word accesses, both of which may be unexpected.
9764 and then Has_Atomic_Components
9768 then
9769 Error_Msg_N
9771 Error_Msg_N
9776 -----------------------------
9777 -- Resolve_Integer_Literal --
9778 -----------------------------
9781 begin
9786 -----------------------------------------
9787 -- Resolve_Interpolated_String_Literal --
9788 -----------------------------------------
9791 is
9794 begin
9800 -- Resolve string elements using the context type; for interpolated
9801 -- expressions there is no need to check if their type has a suitable
9802 -- image function because under Ada 2022 all the types have such
9803 -- function available.
9807 then
9810 -- Must have been rejected during analysis
9813 | N_Integer_Literal
9814 | N_Real_Literal
9815 | N_String_Literal
9816 then
9826 --------------------------------
9827 -- Resolve_Intrinsic_Operator --
9828 --------------------------------
9835 -- True if this is the special mod operator of System.Storage_Elements,
9836 -- which needs to be resolved to the type of the left operand in order
9837 -- to implement the correct semantics.
9843 -- The base type to be used for the operator
9846 -- If the operand is a literal, it cannot be the expression in a
9847 -- conversion. Use a qualified expression instead.
9849 ---------------------
9850 -- Convert_Operand --
9851 ---------------------
9857 begin
9859 Res :=
9865 else
9872 -- Local variables
9878 -- Start of processing for Resolve_Intrinsic_Operator
9880 begin
9881 -- We must preserve the original entity in a generic setting, so that
9882 -- the legality of the operation can be verified in an instance.
9889 when N_Op_Add =>
9890 Op := Standard_Op_Add;
9891 when N_Op_Expon =>
9892 Op := Standard_Op_Expon;
9893 when N_Op_Subtract =>
9894 Op := Standard_Op_Subtract;
9895 when N_Op_Divide =>
9896 Op := Standard_Op_Divide;
9897 when N_Op_Mod =>
9898 Op := Standard_Op_Mod;
9899 when N_Op_Multiply =>
9900 Op := Standard_Op_Multiply;
9901 when N_Op_Rem =>
9902 Op := Standard_Op_Rem;
9904 -- Non-arithmetic operators are handled elsewhere
9906 when N_Op_Boolean
9907 | N_Op_Concat
9908 | N_Op_Shift
9909 =>
9910 raise Program_Error;
9911 end case;
9913 Set_Entity (N, Op);
9914 Set_Is_Overloaded (N, False);
9916 -- If the result or operand types are private, rewrite with unchecked
9917 -- conversions on the operands and the result, to expose the proper
9918 -- underlying numeric type. Likewise for the special mod operator of
9919 -- System.Storage_Elements, to expose the modified base type.
9921 if Is_Private_Type (Typ)
9922 or else Is_Private_Type (Etype (Left_Opnd (N)))
9923 or else Is_Private_Type (Etype (Right_Opnd (N)))
9924 or else Is_Stoele_Mod
9925 then
9926 Arg1 := Convert_Operand (Left_Opnd (N));
9928 if Nkind (N) = N_Op_Expon then
9929 Arg2 := Unchecked_Convert_To (Standard_Integer, Right_Opnd (N));
9930 else
9931 Arg2 := Convert_Operand (Right_Opnd (N));
9932 end if;
9934 if Nkind (Arg1) = N_Type_Conversion then
9935 Save_Interps (Left_Opnd (N), Expression (Arg1));
9936 end if;
9938 if Nkind (Arg2) = N_Type_Conversion then
9939 Save_Interps (Right_Opnd (N), Expression (Arg2));
9940 end if;
9942 Set_Left_Opnd (N, Arg1);
9943 Set_Right_Opnd (N, Arg2);
9945 Set_Etype (N, Btyp);
9946 Rewrite (N, Unchecked_Convert_To (Typ, N));
9947 Resolve (N, Typ);
9949 elsif Typ /= Etype (Left_Opnd (N))
9950 or else Typ /= Etype (Right_Opnd (N))
9951 then
9952 -- Add explicit conversion where needed, and save interpretations in
9953 -- case operands are overloaded.
9955 Arg1 := Convert_To (Typ, Left_Opnd (N));
9956 Arg2 := Convert_To (Typ, Right_Opnd (N));
9958 if Nkind (Arg1) = N_Type_Conversion then
9959 Save_Interps (Left_Opnd (N), Expression (Arg1));
9960 else
9961 Save_Interps (Left_Opnd (N), Arg1);
9962 end if;
9964 if Nkind (Arg2) = N_Type_Conversion then
9965 Save_Interps (Right_Opnd (N), Expression (Arg2));
9966 else
9967 Save_Interps (Right_Opnd (N), Arg2);
9968 end if;
9970 Rewrite (Left_Opnd (N), Arg1);
9971 Rewrite (Right_Opnd (N), Arg2);
9972 Analyze (Arg1);
9973 Analyze (Arg2);
9974 Resolve_Arithmetic_Op (N, Typ);
9976 else
9977 Resolve_Arithmetic_Op (N, Typ);
9978 end if;
9979 end Resolve_Intrinsic_Operator;
9981 --------------------------------------
9982 -- Resolve_Intrinsic_Unary_Operator --
9983 --------------------------------------
9985 procedure Resolve_Intrinsic_Unary_Operator
9986 (N : Node_Id;
9987 Typ : Entity_Id)
9988 is
9989 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
9990 Op : Entity_Id;
9991 Arg2 : Node_Id;
9993 begin
9994 -- We must preserve the original entity in a generic setting, so that
9995 -- the legality of the operation can be verified in an instance.
9997 if not Expander_Active then
9998 return;
9999 end if;
10009 -- Non-arithmetic operators are handled elsewhere
10027 else
10032 ------------------------
10033 -- Resolve_Logical_Op --
10034 ------------------------
10039 begin
10042 -- Predefined operations on scalar types yield the base type. On the
10043 -- other hand, logical operations on arrays yield the type of the
10044 -- arguments (and the context).
10048 else
10052 -- The following test is required because the operands of the operation
10053 -- may be literals, in which case the resulting type appears to be
10054 -- compatible with a signed integer type, when in fact it is compatible
10055 -- only with modular types. If the context itself is universal, the
10056 -- operation is illegal.
10064 Error_Msg_N
10072 then
10076 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
10077 -- is active and the result type is standard Boolean (do not mess with
10078 -- ops that return a nonstandard Boolean type, because something strange
10079 -- is going on).
10081 -- Note: you might expect this replacement to be done during expansion,
10082 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
10083 -- is used, no part of the right operand of an "and" or "or" operator
10084 -- should be executed if the left operand would short-circuit the
10085 -- evaluation of the corresponding "and then" or "or else". If we left
10086 -- the replacement to expansion time, then run-time checks associated
10087 -- with such operands would be evaluated unconditionally, due to being
10088 -- before the condition prior to the rewriting as short-circuit forms
10089 -- during expansion.
10091 if Short_Circuit_And_Or
10094 then
10095 -- Mark the corresponding putative SCO operator as truly a logical
10096 -- (and short-circuit) operator.
10109 -- Case of OR changed to OR ELSE
10111 else
10119 -- Return now, since analysis of the rewritten ops will take care of
10120 -- other reference bookkeeping and expression folding.
10136 ---------------------------------
10137 -- Resolve_Membership_Equality --
10138 ---------------------------------
10143 begin
10144 -- RM 4.5.2(4.1/3): if the type is limited, then it shall have a visible
10145 -- primitive equality operator. This means that we can use the regular
10146 -- visibility-based resolution and reset Entity in order to trigger it.
10151 -- RM 4.5.2(28.1/3): if the type is a record, then the membership test
10152 -- uses the primitive equality for the type [even if it is not visible].
10153 -- We only deal with the untagged case here, because the tagged case is
10154 -- handled uniformly in the expander.
10157 declare
10160 begin
10168 ---------------------------
10169 -- Resolve_Membership_Op --
10170 ---------------------------
10172 -- The context can only be a boolean type, and does not determine the
10173 -- arguments. Arguments should be unambiguous, but the preference rule for
10174 -- universal types applies.
10184 -- Analysis has determined a unique type for the left operand. Use it as
10185 -- the basis to resolve the disjuncts.
10187 ----------------------------
10188 -- Resolve_Set_Membership --
10189 ----------------------------
10194 begin
10195 -- If the left operand is overloaded, find type compatible with not
10196 -- overloaded alternative of the right operand.
10205 else
10210 -- Unclear how to resolve expression if all alternatives are also
10211 -- overloaded.
10217 else
10226 -- Alternative is an expression, a range
10227 -- or a subtype mark.
10231 then
10238 -- Check for duplicates for discrete case
10241 declare
10250 begin
10251 -- Loop checking duplicates. This is quadratic, but giant sets
10252 -- are unlikely in this context so it's a reasonable choice.
10259 | N_Character_Literal
10260 | N_Has_Entity
10261 then
10278 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
10279 -- limited types, evaluation of a membership test uses the predefined
10280 -- equality for the type. This may be confusing to users, and the
10281 -- following warning appears useful for the most common case.
10285 then
10286 Error_Msg_NE
10288 Error_Msg_N
10293 -- Start of processing for Resolve_Membership_Op
10295 begin
10301 Resolve_Set_Membership;
10307 then
10310 -- If the left operand is of a universal numeric type and the right
10311 -- operand is not, we do not resolve the operands to the tested type
10312 -- but to the universal type instead. If not conforming to the letter,
10313 -- it's conforming to the spirit of the specification of membership
10314 -- tests, which are typically used to guard a specific operation and
10315 -- ought not to fail a check in doing so. Without this, in the case of
10317 -- type Small_Length is range 1 .. 16;
10319 -- function Is_Small_String (S : String) return Boolean is
10320 -- begin
10321 -- return S'Length in Small_Length;
10322 -- end;
10324 -- the function Is_Small_String would fail a range check for strings
10325 -- larger than 127 characters.
10327 -- The test on the size is required in GNAT because universal_integer
10328 -- does not cover all the values of all the supported integer types,
10329 -- for example the large values of Long_Long_Long_Unsigned.
10334 or else
10336 and then
10338 or else
10340 then
10343 -- If the right operand is 'Range, we first need to resolve it (to
10344 -- the tested type) so that it is rewritten as an N_Range, before
10345 -- converting its bounds and resolving it again below.
10349 then
10353 -- If the right operand is an N_Range, we convert its bounds to the
10354 -- universal type before resolving it.
10364 -- Ada 2005 (AI-251): Support the following case:
10366 -- type I is interface;
10367 -- type T is tagged ...
10369 -- function Test (O : I'Class) is
10370 -- begin
10371 -- return O in T'Class.
10372 -- end Test;
10374 -- In this case we have nothing else to do. The membership test will be
10375 -- done at run time.
10381 then
10384 else
10388 -- If mixed-mode operations are present and operands are all literal,
10389 -- the only interpretation involves Duration, which is probably not
10390 -- the intention of the programmer.
10405 then
10411 else
10416 -- Here after resolving membership operation
10423 ------------------
10424 -- Resolve_Null --
10425 ------------------
10430 begin
10431 -- Handle restriction against anonymous null access values This
10432 -- restriction can be turned off using -gnatdj.
10434 -- Ada 2005 (AI-231): Remove restriction
10437 and then not Debug_Flag_J
10440 then
10441 -- In the common case of a call which uses an explicitly null value
10442 -- for an access parameter, give specialized error message.
10445 Error_Msg_N
10448 -- Standard message for all other cases (are there any?)
10450 else
10451 Error_Msg_N
10456 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
10457 -- assignment to a null-excluding object.
10462 then
10465 -- Decide whether to generate an if_statement around our
10466 -- null-excluding check to avoid them on certain internal object
10467 -- declarations by looking at the type the current Init_Proc
10468 -- belongs to.
10470 -- Generate:
10471 -- if T1b_skip_null_excluding_check then
10472 -- [constraint_error "access check failed"]
10473 -- end if;
10475 if Needs_Conditional_Null_Excluding_Check
10477 then
10480 Condition =>
10482 New_External_Name
10484 Then_Statements =>
10485 New_List (
10489 -- Otherwise, simply create the check
10491 else
10496 else
10497 Insert_Action
10505 -- In a distributed context, null for a remote access to subprogram may
10506 -- need to be replaced with a special record aggregate. In this case,
10507 -- return after having done the transformation.
10512 then
10516 -- The null literal takes its type from the context
10521 -----------------------
10522 -- Resolve_Op_Concat --
10523 -----------------------
10527 -- We wish to avoid deep recursion, because concatenations are often
10528 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10529 -- operands nonrecursively until we find something that is not a simple
10530 -- concatenation (A in this case). We resolve that, and then walk back
10531 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10532 -- to do the rest of the work at each level. The Parent pointers allow
10533 -- us to avoid recursion, and thus avoid running out of memory. See also
10534 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10539 begin
10540 -- The following code is equivalent to:
10542 -- Resolve_Op_Concat_First (NN, Typ);
10543 -- Resolve_Op_Concat_Arg (N, ...);
10544 -- Resolve_Op_Concat_Rest (N, Typ);
10546 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10547 -- operand is a concatenation.
10549 -- Walk down left operands
10551 loop
10560 -- Now (given the above example) NN is A&B and Op1 is A
10562 -- First resolve Op1 ...
10566 -- ... then walk NN back up until we reach N (where we started), calling
10567 -- Resolve_Op_Concat_Rest along the way.
10569 loop
10576 ---------------------------
10577 -- Resolve_Op_Concat_Arg --
10578 ---------------------------
10580 procedure Resolve_Op_Concat_Arg
10585 is
10589 begin
10591 if Is_Comp
10595 then
10597 else
10601 -- If both Array & Array and Array & Component are visible, there is a
10602 -- potential ambiguity that must be reported.
10607 then
10611 -- If the operation is user-defined and not overloaded use its
10612 -- profile. The operation may be a renaming, in which case it has
10613 -- been rewritten, and we want the original profile.
10618 then
10620 Etype
10624 -- Otherwise an aggregate may match both the array type and the
10625 -- component type.
10627 else
10632 else
10636 then
10637 declare
10642 begin
10647 -- Special-case the error message when the overloading is
10648 -- caused by a function that yields an array and can be
10649 -- called without parameters.
10654 Error_Msg_NE
10656 Error_Msg_NE
10660 else
10668 or else
10670 then
10671 Error_Msg_N -- CODEFIX
10688 then
10689 -- Determine if the out-of-range violation constitutes a
10690 -- warning or an error according to the expression base type,
10691 -- according to Ada 2022 RM 4.9 (35/2).
10694 Apply_Compile_Time_Constraint_Error
10700 Apply_Compile_Time_Constraint_Error
10709 else
10714 else
10721 -----------------------------
10722 -- Resolve_Op_Concat_First --
10723 -----------------------------
10730 begin
10731 -- The parser folds an enormous sequence of concatenations of string
10732 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10733 -- in the right operand. If the expression resolves to a predefined "&"
10734 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10735 -- we give an error. See P_Simple_Expression in Par.Ch4.
10740 then
10755 ----------------------------
10756 -- Resolve_Op_Concat_Rest --
10757 ----------------------------
10763 begin
10772 -- If this is not a static concatenation, but the result is a string
10773 -- type (and not an array of strings) ensure that static string operands
10774 -- have their subtypes properly constructed.
10778 then
10784 ----------------------
10785 -- Resolve_Op_Expon --
10786 ----------------------
10791 begin
10792 -- Catch attempts to do fixed-point exponentiation with universal
10793 -- operands, which is a case where the illegality is not caught during
10794 -- normal operator analysis. This is not done in preanalysis mode
10795 -- since the tree is not fully decorated during preanalysis.
10807 then
10816 then
10826 -- We do the resolution using the base type, because intermediate values
10827 -- in expressions are always of the base type, not a subtype of it.
10832 -- For integer types, right argument must be in Natural range
10847 -- Evaluate the exponentiation operator for dimensioned type
10850 else
10854 -- Set overflow checking bit. Much cleverer code needed here eventually
10855 -- and perhaps the Resolve routines should be separated for the various
10856 -- arithmetic operations, since they will need different processing. ???
10865 --------------------
10866 -- Resolve_Op_Not --
10867 --------------------
10871 -- This function determines if the parent node is a boolean operator or
10872 -- operation (comparison op, membership test, or short circuit form) and
10873 -- the not in question is the left operand of this operation. Note that
10874 -- if the not is in parens, then false is returned.
10876 -----------------------
10877 -- Parent_Is_Boolean --
10878 -----------------------
10881 begin
10884 | N_Op_Boolean
10885 | N_Short_Circuit
10889 -- Local variables
10893 -- Start of processing for Resolve_Op_Not
10895 begin
10896 -- Predefined operations on scalar types yield the base type. On the
10897 -- other hand, logical operations on arrays yield the type of the
10898 -- arguments (and the context).
10902 else
10906 -- Straightforward case of incorrect arguments
10913 -- Special case of probable missing parens
10917 Error_Msg_N
10920 else
10921 Error_Msg_N
10928 -- OK resolution of NOT
10930 else
10931 -- Warn if non-boolean types involved. This is a case like not a < b
10932 -- where a and b are modular, where we will get (not a) < b and most
10933 -- likely not (a < b) was intended.
10935 if Warn_On_Questionable_Missing_Parens
10937 and then Parent_Is_Boolean
10938 then
10942 -- Warn on double negation if checking redundant constructs
10944 if Warn_On_Redundant_Constructs
10949 then
10953 -- Complete resolution and evaluation of NOT
10963 -----------------------------
10964 -- Resolve_Operator_Symbol --
10965 -----------------------------
10967 -- Nothing to be done, all resolved already
10973 begin
10977 ----------------------------------
10978 -- Resolve_Qualified_Expression --
10979 ----------------------------------
10987 begin
10991 -- A qualified expression requires an exact match of the type, class-
10992 -- wide matching is not allowed. However, if the qualifying type is
10993 -- specific and the expression has a class-wide type, it may still be
10994 -- okay, since it can be the result of the expansion of a call to a
10995 -- dispatching function, so we also have to check class-wideness of the
10996 -- type of the expression's original node.
10999 or else
11003 then
11007 -- If the target type is unconstrained, then we reset the type of the
11008 -- result from the type of the expression. For other cases, the actual
11009 -- subtype of the expression is the target type. But we avoid doing it
11010 -- for an allocator since this is not needed and might be problematic.
11015 then
11022 -- If we still have a qualified expression after the static evaluation,
11023 -- then apply a scalar range check if needed. The reason that we do this
11024 -- after the Eval call is that otherwise, the application of the range
11025 -- check may convert an illegal static expression and result in warning
11026 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
11030 then
11034 -- AI12-0100: Once the qualified expression is resolved, check whether
11035 -- operand satisfies a static predicate of the target subtype, if any.
11036 -- In the static expression case, a predicate check failure is an error.
11039 Check_Expression_Against_Static_Predicate
11044 ------------------------------
11045 -- Resolve_Raise_Expression --
11046 ------------------------------
11049 begin
11054 else
11057 -- Apply check for required parentheses in the enclosing
11058 -- context of raise_expressions (RM 11.3 (2)), including default
11059 -- expressions in contexts that can include aspect specifications,
11060 -- and ancestor parts of extension aggregates.
11062 declare
11066 begin
11069 loop
11076 then
11083 if not Parentheses_Found
11085 and then
11087 | N_Floating_Point_Definition
11088 | N_Ordinary_Fixed_Point_Definition
11089 | N_Decimal_Fixed_Point_Definition
11090 | N_Extension_Aggregate
11091 | N_Discriminant_Specification
11092 | N_Parameter_Specification
11093 | N_Formal_Object_Declaration
11096 and then
11098 then
11099 Error_Msg_N
11101 N);
11107 -------------------
11108 -- Resolve_Range --
11109 -------------------
11116 -- Returns True if N is of the form X'First .. X'Last where X is the
11117 -- same entity for both attributes.
11119 --------------------
11120 -- First_Last_Ref --
11121 --------------------
11127 begin
11132 then
11133 declare
11136 begin
11146 -- Start of processing for Resolve_Range
11148 begin
11154 -- Reanalyze the lower bound after both bounds have been analyzed, so
11155 -- that the range is known to be static or not by now. This may trigger
11156 -- more compile-time evaluation, which is useful for static analysis
11157 -- with GNATprove. This is not needed for compilation or static analysis
11158 -- with CodePeer, as full expansion does that evaluation then.
11165 -- Check for inappropriate range on unordered enumeration type
11169 -- Exclude X'First .. X'Last if X is the same entity for both
11171 and then not First_Last_Ref
11172 then
11174 Error_Msg_NE
11181 -- We have to check the bounds for being within the base range as
11182 -- required for a non-static context. Normally this is automatic and
11183 -- done as part of evaluating expressions, but the N_Range node is an
11184 -- exception, since in GNAT we consider this node to be a subexpression,
11185 -- even though in Ada it is not. The circuit in Sem_Eval could check for
11186 -- this, but that would put the test on the main evaluation path for
11187 -- expressions.
11192 -- Check for an ambiguous range over character literals. This will
11193 -- happen with a membership test involving only literals.
11201 -- If bounds are static, constant-fold them, so size computations are
11202 -- identical between front-end and back-end. Do not perform this
11203 -- transformation while analyzing generic units, as type information
11204 -- would be lost when reanalyzing the constant node in the instance.
11216 -- If we have a compile-time-known null range, we warn, because that is
11217 -- likely to be a mistake. (Dynamic null ranges make sense, but often
11218 -- compile-time-known ones do not.) Warn only if this is in a subtype
11219 -- declaration. We do this here, rather than while analyzing a subtype
11220 -- declaration, in case we decide to expand the cases. We do not want to
11221 -- warn in all cases, because some are idiomatic, such as an empty
11222 -- aggregate (1 .. 0 => <>).
11224 -- We don't warn in generics or their instances, because there might be
11225 -- some instances where the range is null, and some where it is not,
11226 -- which would lead to false alarms.
11230 and then Compile_Time_Compare
11236 then
11241 --------------------------
11242 -- Resolve_Real_Literal --
11243 --------------------------
11248 begin
11249 -- Special processing for fixed-point literals to make sure that the
11250 -- value is an exact multiple of the small where this is required. We
11251 -- skip this for the universal real case, and also for generic types.
11257 then
11258 -- We must freeze the base type to get the proper value of the small
11264 declare
11271 begin
11272 -- Case of literal is not an exact multiple of the Small
11276 -- For a source program literal for a decimal fixed-point type,
11277 -- this is statically illegal (RM 4.9(36)).
11282 then
11286 -- Generate a warning if literal from source
11289 and then Warn_On_Bad_Fixed_Value
11290 then
11291 Error_Msg_N
11293 N);
11296 -- Replace literal by a value that is the exact representation
11297 -- of a value of the type, i.e. a multiple of the small value,
11298 -- by truncation, since Machine_Rounds is false for all GNAT
11299 -- fixed-point types (RM 4.9(38)).
11309 -- In all cases, set the corresponding integer field
11315 -- Now replace the actual type by the expected type as usual
11321 -----------------------
11322 -- Resolve_Reference --
11323 -----------------------
11328 begin
11329 -- Replace general access with specific type
11337 -- If we are taking the reference of a volatile entity, then treat it as
11338 -- a potential modification of this entity. This is too conservative,
11339 -- but necessary because remove side effects can cause transformations
11340 -- of normal assignments into reference sequences that otherwise fail to
11341 -- notice the modification.
11348 --------------------------------
11349 -- Resolve_Selected_Component --
11350 --------------------------------
11365 -- Check whether this is the initialization of a component within an
11366 -- init proc (by assignment or call to another init proc). If true,
11367 -- there is no need for a discriminant check.
11369 --------------------
11370 -- Init_Component --
11371 --------------------
11374 begin
11375 return Inside_Init_Proc
11381 -- Start of processing for Resolve_Selected_Component
11383 begin
11386 -- Use the context type to select the prefix that has a selector
11387 -- of the correct name and type.
11395 else
11399 -- Locate selected component. For a private prefix the selector
11400 -- can denote a discriminant.
11404 -- The visible components of a class-wide type are those of
11405 -- the root type.
11415 then
11422 else
11426 Error_Msg_N
11431 else
11434 -- There may be an implicit dereference. Retrieve
11435 -- designated record type.
11439 else
11445 -- Resolution chooses the new interpretation.
11446 -- Find the component with the right name.
11451 loop
11468 -- There must be a legal interpretation at this point
11473 -- In general the expected type is the type of the context, not the
11474 -- type of the candidate selected component.
11479 -- The type of the context and that of the component are
11480 -- compatible and in general identical, but if they are anonymous
11481 -- access-to-subprogram types, the relevant type is that of the
11482 -- component. This matters in Unnest_Subprograms mode, where the
11483 -- relevant context is the one in which the type is declared, not
11484 -- the point of use. This determines what activation record to use.
11489 -- When the type of the component is an access to a class-wide type
11490 -- the relevant type is that of the component (since in such case we
11491 -- may need to generate implicit type conversions or dispatching
11492 -- calls).
11497 then
11501 else
11502 -- Resolve prefix with its type
11507 -- Generate cross-reference. We needed to wait until full overloading
11508 -- resolution was complete to do this, since otherwise we can't tell if
11509 -- we are an lvalue or not.
11513 else
11517 -- If the prefix's type is an access type, get to the real record type.
11518 -- Note: we do not apply an access check because an explicit dereference
11519 -- will be introduced later, and the check will happen there.
11525 else
11529 -- Set flag for expander if discriminant check required on a component
11530 -- appearing within a variant.
11536 and then
11539 and then not Init_Component
11540 then
11548 -- If the prefix is a record conversion, this may be a renamed
11549 -- discriminant whose bounds differ from those of the original
11550 -- one, so we must ensure that a range check is performed.
11555 then
11559 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11565 -- If the record type is atomic and the component is not, then this
11566 -- is worth a warning before Ada 2022, since we have a situation
11567 -- where the access to the component may cause extra read/writes of
11568 -- the atomic object, or partial word accesses, both of which may be
11569 -- unexpected.
11575 then
11576 Error_Msg_N
11579 Error_Msg_N
11589 -------------------
11590 -- Resolve_Shift --
11591 -------------------
11598 begin
11599 -- We do the resolution using the base type, because intermediate values
11600 -- in expressions always are of the base type, not a subtype of it.
11613 ---------------------------
11614 -- Resolve_Short_Circuit --
11615 ---------------------------
11622 begin
11623 -- Ensure all actions associated with the left operand (e.g.
11624 -- finalization of transient objects) are fully evaluated locally within
11625 -- an expression with actions. This is particularly helpful for coverage
11626 -- analysis at the object level. However this should not happen in
11627 -- generics.
11630 declare
11632 begin
11640 -- Set Comes_From_Source on L to preserve warnings for unset
11641 -- reference.
11650 -- Check for issuing warning for always False assert/check, this happens
11651 -- when assertions are turned off, in which case the pragma Assert/Check
11652 -- was transformed into:
11654 -- if False and then <condition> then ...
11656 -- and we detect this pattern
11658 if Warn_On_Assertion_Failure
11665 then
11666 declare
11669 begin
11670 -- Special handling of Asssert pragma
11674 then
11675 declare
11677 Original_Node
11678 (Expression
11681 begin
11682 -- Don't warn if original condition is explicit False,
11683 -- since obviously the failure is expected in this case.
11687 then
11690 -- Issue warning. We do not want the deletion of the
11691 -- IF/AND-THEN to take this message with it. We achieve this
11692 -- by making sure that the expanded code points to the Sloc
11693 -- of the expression, not the original pragma.
11695 else
11696 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11697 -- The source location of the expression is not usually
11698 -- the best choice here. For example, it gets located on
11699 -- the last AND keyword in a chain of boolean expressiond
11700 -- AND'ed together. It is best to put the message on the
11701 -- first character of the assertion, which is the effect
11702 -- of the First_Node call here.
11704 Error_Msg_F
11706 Expression
11711 -- Similar processing for Check pragma
11715 then
11716 -- Don't want to warn if original condition is explicit False
11718 declare
11720 Original_Node
11721 (Expression
11723 begin
11726 then
11729 -- Post warning
11731 else
11732 -- Again use Error_Msg_F rather than Error_Msg_N, see
11733 -- comment above for an explanation of why we do this.
11735 Error_Msg_F
11737 Expression
11745 -- Continue with processing of short circuit
11754 -------------------
11755 -- Resolve_Slice --
11756 -------------------
11765 begin
11768 -- Use the context type to select the prefix that yields the correct
11769 -- array type.
11771 declare
11777 begin
11785 then
11793 else
11798 else
11809 else
11815 -- If the prefix's type is an access type, get to the real array type.
11816 -- Note: we do not apply an access check because an explicit dereference
11817 -- will be introduced later, and the check will happen there.
11822 -- If the prefix is an access to an unconstrained array, we must use
11823 -- the actual subtype of the object to perform the index checks. The
11824 -- object denoted by the prefix is implicit in the node, so we build
11825 -- an explicit representation for it in order to compute the actual
11826 -- subtype.
11831 declare
11835 begin
11842 -- In CodePeer mode the attribute Image is not expanded, so when it
11843 -- acts as a prefix of a slice, we handle it like a call to function
11844 -- returning an unconstrained string. Same for the Wide variants of
11845 -- attribute Image.
11854 | Name_Wide_Image
11855 | Name_Wide_Wide_Image)
11856 then
11859 -- If the name is a selected component that depends on discriminants,
11860 -- build an actual subtype for it. This can happen only when the name
11861 -- itself is overloaded; otherwise the actual subtype is created when
11862 -- the selected component is analyzed.
11865 and then Full_Analysis
11867 then
11868 declare
11871 begin
11876 -- Maybe this should just be "else", instead of checking for the
11877 -- specific case of slice??? This is needed for the case where the
11878 -- prefix is an Image attribute, which gets expanded to a slice, and so
11879 -- has a constrained subtype which we want to use for the slice range
11880 -- check applied below (the range check won't get done if the
11881 -- unconstrained subtype of the 'Image is used).
11887 -- Obtain the type of the array index
11891 else
11895 -- If name was overloaded, set slice type correctly now
11899 -- Handle the generation of a range check that compares the array index
11900 -- against the discrete_range. The check is not applied to internally
11901 -- built nodes associated with the expansion of dispatch tables. Check
11902 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11903 -- the unit.
11905 if Tagged_Type_Expansion
11911 then
11914 -- The discrete_range is specified by a subtype name. Create an
11915 -- equivalent range attribute, apply checks to this attribute, but
11916 -- insert them into the range expression of the slice itself.
11919 Dexpr :=
11920 Make_Attribute_Reference
11922 Prefix =>
11931 -- The discrete_range is a regular range (or a range attribute, which
11932 -- will be resolved into a regular range). Resolve the bounds and remove
11933 -- their side effects.
11935 else
11952 -- Check bad use of type with predicates
11954 declare
11957 begin
11960 then
11962 else
11967 Bad_Predicated_Subtype_Use
11972 -- Otherwise here is where we check suspicious indexes
11984 ----------------------------
11985 -- Resolve_String_Literal --
11986 ----------------------------
11997 begin
11998 -- For a string appearing in a concatenation, defer creation of the
11999 -- string_literal_subtype until the end of the resolution of the
12000 -- concatenation, because the literal may be constant-folded away. This
12001 -- is a useful optimization for long concatenation expressions.
12003 -- If the string is an aggregate built for a single character (which
12004 -- happens in a non-static context) or a is null string to which special
12005 -- checks may apply, we build the subtype. Wide strings must also get a
12006 -- string subtype if they come from a one character aggregate. Strings
12007 -- generated by attributes might be static, but it is often hard to
12008 -- determine whether the enclosing context is static, so we generate
12009 -- subtypes for them as well, thus losing some rarer optimizations ???
12010 -- Same for strings that come from a static conversion.
12012 Need_Check :=
12021 -- If the resolving type is itself a string literal subtype, we can just
12022 -- reuse it, since there is no point in creating another.
12028 and then not Need_Check
12030 | N_Attribute_Reference
12031 | N_Qualified_Expression
12032 | N_Type_Conversion
12033 then
12036 -- Do not generate a string literal subtype for the default expression
12037 -- of a formal parameter in GNATprove mode. This is because the string
12038 -- subtype is associated with the freezing actions of the subprogram,
12039 -- however freezing is disabled in GNATprove mode and as a result the
12040 -- subtype is unavailable.
12042 elsif GNATprove_Mode
12044 then
12047 -- Otherwise we must create a string literal subtype. Note that the
12048 -- whole idea of string literal subtypes is simply to avoid the need
12049 -- for building a full fledged array subtype for each literal.
12051 else
12057 or else Need_Check
12058 then
12065 then
12071 -- The validity of a null string has been checked in the call to
12072 -- Eval_String_Literal.
12077 -- Always accept string literal with component type Any_Character, which
12078 -- occurs in error situations and in comparisons of literals, both of
12079 -- which should accept all literals.
12084 -- If the type is bit-packed, then we always transform the string
12085 -- literal into a full fledged aggregate.
12090 -- Deal with cases of Wide_Wide_String, Wide_String, and String
12092 else
12093 -- For Standard.Wide_Wide_String, or any other type whose component
12094 -- type is Standard.Wide_Wide_Character, we know that all the
12095 -- characters in the string must be acceptable, since the parser
12096 -- accepted the characters as valid character literals.
12101 -- For the case of Standard.String, or any other type whose component
12102 -- type is Standard.Character, we must make sure that there are no
12103 -- wide characters in the string, i.e. that it is entirely composed
12104 -- of characters in range of type Character.
12106 -- If the string literal is the result of a static concatenation, the
12107 -- test has already been performed on the components, and need not be
12108 -- repeated.
12112 then
12116 -- If we are out of range, post error. This is one of the
12117 -- very few places that we place the flag in the middle of
12118 -- a token, right under the offending wide character. Not
12119 -- quite clear if this is right wrt wide character encoding
12120 -- sequences, but it's only an error message.
12122 Error_Msg
12129 -- For the case of Standard.Wide_String, or any other type whose
12130 -- component type is Standard.Wide_Character, we must make sure that
12131 -- there are no wide characters in the string, i.e. that it is
12132 -- entirely composed of characters in range of type Wide_Character.
12134 -- If the string literal is the result of a static concatenation,
12135 -- the test has already been performed on the components, and need
12136 -- not be repeated.
12140 then
12144 -- If we are out of range, post error. This is one of the
12145 -- very few places that we place the flag in the middle of
12146 -- a token, right under the offending wide character.
12148 -- This is not quite right, because characters in general
12149 -- will take more than one character position ???
12151 Error_Msg
12158 -- If the root type is not a standard character, then we will convert
12159 -- the string into an aggregate and will let the aggregate code do
12160 -- the checking. Standard Wide_Wide_Character is also OK here.
12162 else
12166 -- See if the component type of the array corresponding to the string
12167 -- has compile time known bounds. If yes we can directly check
12168 -- whether the evaluation of the string will raise constraint error.
12169 -- Otherwise we need to transform the string literal into the
12170 -- corresponding character aggregate and let the aggregate code do
12171 -- the checking. We use the same transformation if the component
12172 -- type has a static predicate, which will be applied to each
12173 -- character when the aggregate is resolved.
12177 -- Check for the case of full range, where we are definitely OK
12183 -- Here the range is not the complete base type range, so check
12185 declare
12193 begin
12196 then
12202 then
12203 Apply_Compile_Time_Constraint_Error
12205 CE_Range_Check_Failed,
12218 -- If we got here we meed to transform the string literal into the
12219 -- equivalent qualified positional array aggregate. This is rather
12220 -- heavy artillery for this situation, but it is hard work to avoid.
12222 declare
12227 begin
12228 -- Build the character literals, we give them source locations that
12229 -- correspond to the string positions, which is a bit tricky given
12230 -- the possible presence of wide character escape sequences.
12244 -- Should we have a call to Skip_Wide here ???
12246 -- ??? else
12247 -- Skip_Wide (P);
12255 Expression =>
12262 -------------------------
12263 -- Resolve_Target_Name --
12264 -------------------------
12267 begin
12271 -----------------------------
12272 -- Resolve_Type_Conversion --
12273 -----------------------------
12285 -- Set to False to suppress cases where we want to suppress the test
12286 -- for redundancy to avoid possible false positives on this warning.
12288 begin
12289 if not Conv_OK
12291 then
12295 -- If the Operand Etype is Universal_Fixed, then the conversion is
12296 -- never redundant. We need this check because by the time we have
12297 -- finished the rather complex transformation, the conversion looks
12298 -- redundant when it is not.
12303 -- If the operand is marked as Any_Fixed, then special processing is
12304 -- required. This is also a case where we suppress the test for a
12305 -- redundant conversion, since most certainly it is not redundant.
12310 -- Mixed-mode operation involving a literal. Context must be a fixed
12311 -- type which is applied to the literal subsequently.
12313 -- Multiplication and division involving two fixed type operands must
12314 -- yield a universal real because the result is computed in arbitrary
12315 -- precision.
12321 then
12327 or else
12329 then
12330 -- Return if expression is ambiguous
12335 -- If nothing else, the available fixed type is Duration
12337 else
12341 -- Resolve the real operand with largest available precision
12345 else
12351 -- If the operand is a literal (it could be a non-static and
12352 -- illegal exponentiation) check whether the use of Duration
12353 -- is potentially inaccurate.
12358 then
12359 Error_Msg_N
12362 Error_Msg_N
12369 then
12372 else
12383 -- Note: we do the Eval_Type_Conversion call before applying the
12384 -- required checks for a subtype conversion. This is important, since
12385 -- both are prepared under certain circumstances to change the type
12386 -- conversion to a constraint error node, but in the case of
12387 -- Eval_Type_Conversion this may reflect an illegality in the static
12388 -- case, and we would miss the illegality (getting only a warning
12389 -- message), if we applied the type conversion checks first.
12393 -- Even when evaluation is not possible, we may be able to simplify the
12394 -- conversion or its expression. This needs to be done before applying
12395 -- checks, since otherwise the checks may use the original expression
12396 -- and defeat the simplifications. This is specifically the case for
12397 -- elimination of the floating-point Truncation attribute in
12398 -- float-to-int conversions.
12402 -- If after evaluation we still have a type conversion, then we may need
12403 -- to apply checks required for a subtype conversion. But skip them if
12404 -- universal fixed operands are involved, since range checks are handled
12405 -- separately for these cases, after the expansion done by Exp_Fixd.
12411 then
12415 -- Issue warning for conversion of simple object to its own type. We
12416 -- have to test the original nodes, since they may have been rewritten
12417 -- by various optimizations.
12421 -- Here we test for a redundant conversion if the warning mode is
12422 -- active (and was not locally reset), and we have a type conversion
12423 -- from source not appearing in a generic instance.
12425 if Test_Redundant
12428 and then not In_Instance
12429 then
12433 -- If the node is part of a larger expression, the Target_Type
12434 -- may not be the original type of the node if the context is a
12435 -- condition. Recover original type to see if conversion is needed.
12439 then
12443 -- If we have an entity name, then give the warning if the entity
12444 -- is the right type, or if it is a loop parameter covered by the
12445 -- original type (that's needed because loop parameters have an
12446 -- odd subtype coming from the bounds).
12450 and then
12452 or else
12456 -- If not an entity, then type of expression must match
12459 then
12460 -- One more check, do not give warning if the analyzed conversion
12461 -- has an expression with non-static bounds, and the bounds of the
12462 -- target are static. This avoids junk warnings in cases where the
12463 -- conversion is necessary to establish staticness, for example in
12464 -- a case statement.
12468 then
12471 -- Never give a warning if the operand is a conditional expression
12472 -- because RM 4.5.7(10/3) forces its type to be the target type.
12477 -- Finally, if this type conversion occurs in a context requiring
12478 -- a prefix, and the expression is a qualified expression then the
12479 -- type conversion is not redundant, since a qualified expression
12480 -- is not a prefix, whereas a type conversion is. For example, "X
12481 -- := T'(Funx(...)).Y;" is illegal because a selected component
12482 -- requires a prefix, but a type conversion makes it legal: "X :=
12483 -- T(T'(Funx(...))).Y;"
12485 -- In Ada 2012, a qualified expression is a name, so this idiom is
12486 -- no longer needed, but we still suppress the warning because it
12487 -- seems unfriendly for warnings to pop up when you switch to the
12488 -- newer language version.
12492 | N_Indexed_Component
12493 | N_Selected_Component
12494 | N_Slice
12495 | N_Explicit_Dereference
12496 then
12499 -- Never warn on conversion to Long_Long_Integer'Base since
12500 -- that is most likely an artifact of the extended overflow
12501 -- checking and comes from complex expanded code.
12506 -- Do not warn on conversion to class-wide type on helpers of
12507 -- class-wide preconditions because in this context the warning
12508 -- would be spurious (since the class-wide precondition has been
12509 -- installed in the return statement of the helper, which has a
12510 -- class-wide formal type instead of a regular tagged type).
12515 then
12518 -- Here we give the redundant conversion warning. If it is an
12519 -- entity, give the name of the entity in the message. If not,
12520 -- just mention the expression.
12522 else
12525 Error_Msg_NE -- CODEFIX
12528 else
12529 Error_Msg_NE
12537 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12538 -- No need to perform any interface conversion if the type of the
12539 -- expression coincides with the target type.
12542 and then Expander_Active
12544 then
12545 declare
12549 begin
12550 -- If the type of the operand is a limited view, use nonlimited
12551 -- view when available. If it is a class-wide type, recover the
12552 -- class-wide type of the nonlimited view.
12556 then
12561 -- It seems that Non_Limited_View should also be applied for
12562 -- Target when it has a limited view, but that leads to missing
12563 -- error checks on interface conversions further below. ???
12568 -- If the type of the operand is a limited view, use nonlimited
12569 -- view when available. If it is a class-wide type, recover the
12570 -- class-wide type of the nonlimited view.
12574 then
12582 -- If the target type is a limited view, use nonlimited view
12583 -- when available.
12587 then
12595 -- Conversion from interface type
12597 -- It seems that it would be better for the error checks below
12598 -- to be performed as part of Validate_Conversion (and maybe some
12599 -- of the error checks above could be moved as well?). ???
12603 -- Ada 2005 (AI-217): Handle entities from limited views
12607 Error_Msg_NE -- CODEFIX
12610 Error_Msg_N
12612 N);
12615 and then not
12618 then
12620 Error_Msg_NE -- CODEFIX
12623 Error_Msg_N
12625 N);
12627 else
12631 -- Conversion to interface type
12639 -- Ada 2012: Once the type conversion is resolved, check whether the
12640 -- operand satisfies a static predicate of the target subtype, if any.
12641 -- In the static expression case, a predicate check failure is an error.
12644 Check_Expression_Against_Static_Predicate
12648 -- If at this stage we have a fixed to integer conversion, make sure the
12649 -- Do_Range_Check flag is set, because such conversions in general need
12650 -- a range check. We only need this if expansion is off, see above why.
12653 and then not Expander_Active
12658 then
12663 ----------------------
12664 -- Resolve_Unary_Op --
12665 ----------------------
12674 begin
12675 -- Deal with intrinsic unary operators
12681 then
12686 -- Deal with universal cases
12695 -- Generate warning for negative literal of a modular type, unless it is
12696 -- enclosed directly in a type qualification or a type conversion, as it
12697 -- is likely not what the user intended. We don't issue the warning for
12698 -- the common use of -1 to denote OxFFFF_FFFF...
12700 if Warn_On_Suspicious_Modulus_Value
12706 | N_Type_Conversion
12708 then
12709 Error_Msg_N
12714 Error_Msg_N
12718 -- Generate warning for expressions like abs (x mod 2)
12720 if Warn_On_Redundant_Constructs
12722 then
12726 Error_Msg_N -- CODEFIX
12731 -- Deal with reference generation
12738 -- Set overflow checking bit. Much cleverer code needed here eventually
12739 -- and perhaps the Resolve routines should be separated for the various
12740 -- arithmetic operations, since they will need different processing ???
12748 -- Generate warning for expressions like -5 mod 3 for integers. No need
12749 -- to worry in the floating-point case, since parens do not affect the
12750 -- result so there is no point in giving in a warning.
12752 declare
12761 begin
12762 if Warn_On_Questionable_Missing_Parens
12766 then
12769 -- We are looking for cases where the right operand is not
12770 -- parenthesized, and is a binary operator, multiply, divide, or
12771 -- mod. These are the cases where the grouping can affect results.
12775 then
12776 -- For mod, we always give the warning, since the value is
12777 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12778 -- -(5 mod 315)). But for the other cases, the only concern is
12779 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12780 -- overflows, but (-2) * 64 does not). So we try to give the
12781 -- message only when overflow is possible.
12785 then
12790 else
12796 else
12800 -- Note that the test below is deliberately excluding the
12801 -- largest negative number, since that is a potentially
12802 -- troublesome case (e.g. -2 * x, where the result is the
12803 -- largest negative integer has an overflow with 2 * x).
12810 -- For the multiplication case, the only case we have to worry
12811 -- about is when (-a)*b is exactly the largest negative number
12812 -- so that -(a*b) can cause overflow. This can only happen if
12813 -- a is a power of 2, and more generally if any operand is a
12814 -- constant that is not a power of 2, then the parentheses
12815 -- cannot affect whether overflow occurs. We only bother to
12816 -- test the left most operand
12818 -- Loop looking at left operands for one that has known value
12825 -- Operand value of 0 or 1 skips warning
12830 -- Otherwise check power of 2, if power of 2, warn, if
12831 -- anything else, skip warning.
12833 else
12837 else
12846 -- Keep looking at left operands
12851 -- For rem or "/" we can only have a problematic situation
12852 -- if the divisor has a value of minus one or one. Otherwise
12853 -- overflow is impossible (divisor > 1) or we have a case of
12854 -- division by zero in any case.
12859 then
12863 -- If we fall through warning should be issued
12865 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12867 Error_Msg_N
12874 ----------------------------------
12875 -- Resolve_Unchecked_Expression --
12876 ----------------------------------
12878 procedure Resolve_Unchecked_Expression
12881 is
12882 begin
12887 ---------------------------------------
12888 -- Resolve_Unchecked_Type_Conversion --
12889 ---------------------------------------
12891 procedure Resolve_Unchecked_Type_Conversion
12894 is
12900 begin
12901 -- Resolve operand using its own type
12905 -- If the expression is a conversion to universal integer of an
12906 -- an expression with an integer type, then we can eliminate the
12907 -- intermediate conversion to universal integer.
12912 then
12917 -- In an inlined context, the unchecked conversion may be applied
12918 -- to a literal, in which case its type is the type of the context.
12919 -- (In other contexts conversions cannot apply to literals).
12921 if In_Inlined_Body
12925 then
12933 ------------------------------
12934 -- Rewrite_Operator_As_Call --
12935 ------------------------------
12942 begin
12949 New_N :=
12960 ------------------------------
12961 -- Rewrite_Renamed_Operator --
12962 ------------------------------
12964 procedure Rewrite_Renamed_Operator
12968 is
12973 begin
12974 -- Do not perform this transformation within a pre/postcondition,
12975 -- because the expression will be reanalyzed, and the transformation
12976 -- might affect the visibility of the operator, e.g. in an instance.
12977 -- Note that fully analyzed and expanded pre/postconditions appear as
12978 -- pragma Check equivalents.
12984 -- Likewise when an expression function is being preanalyzed, since the
12985 -- expression will be reanalyzed as part of the generated body.
12988 declare
12990 begin
12993 N_Expression_Function
12994 then
13010 -- Indicate that both the original entity and its renaming are
13011 -- referenced at this point.
13018 -- If the context type is private, add the appropriate conversions so
13019 -- that the operator is applied to the full view. This is done in the
13020 -- routines that resolve intrinsic operators.
13024 when N_Op_Add
13025 | N_Op_Divide
13026 | N_Op_Expon
13027 | N_Op_Mod
13028 | N_Op_Multiply
13029 | N_Op_Rem
13030 | N_Op_Subtract
13031 =>
13034 when N_Op_Abs
13035 | N_Op_Minus
13036 | N_Op_Plus
13037 =>
13046 -----------------------
13047 -- Set_Slice_Subtype --
13048 -----------------------
13050 -- Build an implicit subtype declaration to represent the type delivered by
13051 -- the slice. This is an abbreviated version of an array subtype. We define
13052 -- an index subtype for the slice, using either the subtype name or the
13053 -- discrete range of the slice. To be consistent with index usage elsewhere
13054 -- we create a list header to hold the single index. This list is not
13055 -- otherwise attached to the syntax tree.
13066 begin
13072 else
13073 -- We force the evaluation of a range. This is definitely needed in
13074 -- the renamed case, and seems safer to do unconditionally. Note in
13075 -- any case that since we will create and insert an Itype referring
13076 -- to this range, we must make sure any side effect removal actions
13077 -- are inserted before the Itype definition.
13083 -- If the discrete range is given by a subtype indication, the
13084 -- type of the slice is the base of the subtype mark.
13087 declare
13089 begin
13098 -- Take a new copy of Drange (where bounds have been rewritten to
13099 -- reference side-effect-free names). Using a separate tree ensures
13100 -- that further expansion (e.g. while rewriting a slice assignment
13101 -- into a FOR loop) does not attempt to remove side effects on the
13102 -- bounds again (which would cause the bounds in the index subtype
13103 -- definition to refer to temporaries before they are defined) (the
13104 -- reason is that some names are considered side effect free here
13105 -- for the subtype, but not in the context of a loop iteration
13106 -- scheme).
13128 -- The Etype of the existing Slice node is reset to this slice subtype.
13129 -- Its bounds are obtained from its first index.
13133 -- For bit-packed slice subtypes, freeze immediately (except in the case
13134 -- of being in a "spec expression" where we never freeze when we first
13135 -- see the expression).
13140 -- For all other cases insert an itype reference in the slice's actions
13141 -- so that the itype is frozen at the proper place in the tree (i.e. at
13142 -- the point where actions for the slice are analyzed). Note that this
13143 -- is different from freezing the itype immediately, which might be
13144 -- premature (e.g. if the slice is within a transient scope). This needs
13145 -- to be done only if expansion is enabled.
13152 --------------------------------
13153 -- Set_String_Literal_Subtype --
13154 --------------------------------
13163 -- Sinput.Source_Last points to an EOF character that's not in the
13164 -- original file and we do not include that character.
13170 begin
13181 -- The low bound is set from the low bound of the corresponding index
13182 -- type. Note that we do not store the high bound in the string literal
13183 -- subtype, but it can be deduced if necessary from the length and the
13184 -- low bound.
13189 -- If the lower bound is not static we create a range for the string
13190 -- literal, using the index type and the known length of the literal.
13191 -- If the length is 1, then the upper bound is set to a mere copy of
13192 -- the lower bound; or else, if the index type is a signed integer,
13193 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
13194 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
13196 else
13197 declare
13206 begin
13211 High_Bound :=
13216 else
13217 High_Bound :=
13220 Prefix =>
13224 Left_Opnd =>
13227 Prefix =>
13229 Expressions =>
13231 Right_Opnd =>
13236 Set_String_Literal_Low_Bound
13239 else
13240 -- If the index type is an enumeration type, build bounds
13241 -- expression with attributes.
13243 Set_String_Literal_Low_Bound
13247 Prefix =>
13251 Analyze_And_Resolve
13254 -- Build bona fide subtype for the string, and wrap it in an
13255 -- unchecked conversion, because the back end expects the
13256 -- String_Literal_Subtype to have a static lower bound.
13258 Index_Subtype :=
13265 -- In this context, the Index_Type may already have a constraint,
13266 -- so use common base type on string subtype. The base type may
13267 -- be used when generating attributes of the string, for example
13268 -- in the context of a slice assignment.
13290 ------------------------------
13291 -- Simplify_Type_Conversion --
13292 ------------------------------
13295 begin
13297 declare
13302 begin
13303 -- Special processing if the conversion is the expression of a
13304 -- Rounding or Truncation attribute reference. In this case we
13305 -- replace:
13307 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
13309 -- by
13311 -- ityp (x)
13313 -- with the Float_Truncate flag set to False or True respectively,
13314 -- which is more efficient. We reuse Rounding for Machine_Rounding
13315 -- as System.Fat_Gen, which is a permissible behavior.
13318 and then
13324 | Name_Machine_Rounding
13325 | Name_Truncation
13326 then
13327 declare
13330 begin
13336 -- Special processing for the conversion of an integer literal to
13337 -- a dynamic type: we first convert the literal to the root type
13338 -- and then convert the result to the target type, the goal being
13339 -- to avoid doing range checks in universal integer.
13345 then
13349 -- If the expression is a conversion to universal integer of an
13350 -- an expression with an integer type, then we can eliminate the
13351 -- intermediate conversion to universal integer.
13356 then
13364 ------------------------------
13365 -- Try_User_Defined_Literal --
13366 ------------------------------
13368 function Try_User_Defined_Literal
13371 is
13372 begin
13377 -- Both dependent expressions must have the same type as the context
13379 declare
13384 begin
13398 -- All dependent expressions must have the same type as the context
13400 declare
13403 begin
13408 then
13409 declare
13412 begin
13436 -------------------------------------------
13437 -- Try_User_Defined_Literal_For_Operator --
13438 -------------------------------------------
13440 function Try_User_Defined_Literal_For_Operator
13443 is
13444 begin
13446 | N_Op_Divide
13447 | N_Op_Mod
13448 | N_Op_Multiply
13449 | N_Op_Rem
13450 | N_Op_Subtract
13451 then
13452 -- Both operands must have the same type as the context
13453 -- (ignoring for now fixed-point and exponentiation ops).
13458 then
13466 then
13473 -- For other binary operators the context does not impose a type on
13474 -- the operands, but their types must match.
13477 not in N_Integer_Literal | N_String_Literal | N_Real_Literal
13478 and then
13479 Has_Applicable_User_Defined_Literal
13481 then
13486 not in N_Integer_Literal | N_String_Literal | N_Real_Literal
13487 and then
13488 Has_Applicable_User_Defined_Literal
13490 then
13497 then
13505 -----------------------------
13506 -- Unique_Fixed_Point_Type --
13507 -----------------------------
13511 -- Give error messages for true ambiguity. Messages are posted on node
13512 -- N, and entities T1, T2 are the possible interpretations.
13514 -----------------------
13515 -- Fixed_Point_Error --
13516 -----------------------
13519 begin
13525 -- Local variables
13533 -- Start of processing for Unique_Fixed_Point_Type
13535 begin
13536 -- The operations on Duration are visible, so Duration is always a
13537 -- possible interpretation.
13541 -- Look for fixed-point types in enclosing scopes
13550 then
13554 else
13565 -- Look for visible fixed type declarations in the context
13576 then
13580 else
13595 else
13596 -- When the context is a type conversion, issue the warning on the
13597 -- expression of the conversion because it is the actual operation.
13601 else
13605 Error_Msg_NE
13612 ----------------------
13613 -- Valid_Conversion --
13614 ----------------------
13616 function Valid_Conversion
13621 is
13626 function Conversion_Check
13629 -- Little routine to post Msg if Valid is False, returns Valid value
13632 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13634 procedure Conversion_Error_NE
13638 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13641 -- Return True if expression is within an instance but is not in one of
13642 -- the actuals of the instantiation. Type conversions within an instance
13643 -- are not rechecked because type visibility may lead to spurious errors
13644 -- but conversions in an actual for a formal object must be checked.
13646 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13648 -- Implicit anonymous-to-named access type conversions are not allowed
13649 -- if the "statically deeper than" relationship does not apply to the
13650 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13651 -- We deal with most such cases elsewhere so that we can emit more
13652 -- specific error messages (e.g., if the operand is an access parameter
13653 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13654 -- here is where we catch the case where the operand is an access
13655 -- discriminant selected from a dereference of another such "bad"
13656 -- conversion argument.
13658 function Valid_Tagged_Conversion
13661 -- Specifically test for validity of tagged conversions
13664 -- Check index and component conformance, and accessibility levels if
13665 -- the component types are anonymous access types (Ada 2005).
13667 ----------------------
13668 -- Conversion_Check --
13669 ----------------------
13671 function Conversion_Check
13674 is
13675 begin
13676 if not Valid
13678 -- A generic unit has already been analyzed and we have verified
13679 -- that a particular conversion is OK in that context. Since the
13680 -- instance is reanalyzed without relying on the relationships
13681 -- established during the analysis of the generic, it is possible
13682 -- to end up with inconsistent views of private types. Do not emit
13683 -- the error message in such cases. The rest of the machinery in
13684 -- Valid_Conversion still ensures the proper compatibility of
13685 -- target and operand types.
13687 and then not In_Instance_Code
13688 then
13695 ------------------------
13696 -- Conversion_Error_N --
13697 ------------------------
13700 begin
13706 -------------------------
13707 -- Conversion_Error_NE --
13708 -------------------------
13710 procedure Conversion_Error_NE
13714 is
13715 begin
13721 ----------------------
13722 -- In_Instance_Code --
13723 ----------------------
13728 begin
13732 else
13736 -- The expression is part of an actual object if it appears in
13737 -- the generated object declaration in the instance.
13741 then
13744 else
13745 exit when
13754 -- Otherwise the expression appears within the instantiated unit
13760 --------------------------------------------------
13761 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13762 --------------------------------------------------
13764 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13766 is
13772 begin
13784 -- return False if Expr not of form <prefix>.all.Some_Component
13788 then
13789 -- conditional expressions, declare expressions ???
13796 -- The "statically deeper relationship" does not apply
13797 -- to generic formal access types, so a prefix of such
13798 -- a type is a "bad" prefix.
13803 -- The "statically deeper relationship" does apply to
13804 -- any other named access type.
13813 -- The "statically deeper relationship" applies to some
13814 -- anonymous access types and not to others. Return
13815 -- True for the cases where it does not apply. Also check
13816 -- recursively for the
13817 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13818 -- where the correct result depends on <prefix>.
13821 N_Procedure_Specification | -- access parameter
13822 N_Function_Specification | -- access parameter
13823 N_Object_Declaration -- saooaaat
13827 ----------------------------
13828 -- Valid_Array_Conversion --
13829 ----------------------------
13846 begin
13847 -- Error if wrong number of dimensions
13849 if
13851 then
13852 Conversion_Error_N
13856 -- Number of dimensions matches
13858 else
13859 -- Loop through indexes of the two arrays
13867 -- Error if index types are incompatible
13873 then
13874 Conversion_Error_N
13876 Operand);
13884 -- If component types have same base type, all set
13889 -- Here if base types of components are not the same. The only
13890 -- time this is allowed is if we have anonymous access types.
13892 -- The conversion of arrays of anonymous access types can lead
13893 -- to dangling pointers. AI-392 formalizes the accessibility
13894 -- checks that must be applied to such conversions to prevent
13895 -- out-of-scope references.
13898 E_Anonymous_Access_Type
13899 | E_Anonymous_Access_Subprogram_Type
13901 and then
13903 then
13906 then
13909 Conversion_Error_N
13919 -- Conversion not allowed because of accessibility levels
13921 else
13922 Conversion_Error_N
13928 else
13932 -- All other cases where component base types do not match
13934 else
13935 Conversion_Error_N
13937 Operand);
13941 -- Check that component subtypes statically match. For numeric
13942 -- types this means that both must be either constrained or
13943 -- unconstrained. For enumeration types the bounds must match.
13944 -- All of this is checked in Subtypes_Statically_Match.
13946 if not Subtypes_Statically_Match
13948 then
13949 Conversion_Error_N
13958 -----------------------------
13959 -- Valid_Tagged_Conversion --
13960 -----------------------------
13962 function Valid_Tagged_Conversion
13965 is
13966 begin
13967 -- Upward conversions are allowed (RM 4.6(22))
13971 then
13974 -- Downward conversion are allowed if the operand is class-wide
13975 -- (RM 4.6(23)).
13979 then
13984 then
13985 -- Deal with non-extension derivation involving an
13986 -- untagged view of a tagged type.
13992 return
13996 -- Ada 2005 (AI-251): A conversion is valid if the operand and target
13997 -- types are both class-wide types and the specific type associated
13998 -- with at least one of them is an interface type (RM 4.6 (23.1/2));
13999 -- at run-time a check will verify the validity of this interface
14000 -- type conversion.
14006 then
14009 -- Report errors
14014 and then not Interface_Present_In_Ancestor
14017 then
14020 Conversion_Error_N
14028 and then not Interface_Present_In_Ancestor
14031 then
14034 Conversion_Error_N
14038 -- Search for interface types shared between the target type and
14039 -- the operand interface type to complete the text of the error
14040 -- since the source of this error is a missing type conversion
14041 -- to such interface type.
14044 declare
14051 begin
14053 Target_Ifaces_List);
14055 Operand_Ifaces_List);
14063 then
14064 Error_Msg_Name_1 :=
14069 Conversion_Error_N
14072 else
14073 Conversion_Error_N
14091 then
14092 Conversion_Error_N
14094 Conversion_Error_N
14100 then
14101 Conversion_Error_N
14106 else
14107 Conversion_Error_NE
14114 -- Start of processing for Valid_Conversion
14116 begin
14120 declare
14128 begin
14129 -- Remove procedure calls, which syntactically cannot appear in
14130 -- this context, but which cannot be removed by type checking,
14131 -- because the context does not impose a type.
14133 -- The node may be labelled overloaded, but still contain only one
14134 -- interpretation because others were discarded earlier. If this
14135 -- is the case, retain the single interpretation if legal.
14143 then
14144 -- More than one candidate interpretation is available
14152 -- When compiling for a system where Address is of a visible
14153 -- integer type, spurious ambiguities can be produced when
14154 -- arithmetic operations have a literal operand and return
14155 -- System.Address or a descendant of it. These ambiguities
14156 -- are usually resolved by the context, but for conversions
14157 -- there is no context type and the removal of the spurious
14158 -- operations must be done explicitly here.
14160 if not Address_Is_Private
14162 then
14187 Conversion_Error_N
14190 -- If the interpretation involves a standard operator, use
14191 -- the location of the type, which may be user-defined.
14195 else
14199 Conversion_Error_N -- CODEFIX
14204 else
14208 Conversion_Error_N -- CODEFIX
14220 -- When we encounter a class-wide equivalent type used to represent
14221 -- a fully sized mutably tagged type, pretend we are actually looking
14222 -- at the class-wide mutably tagged type instead.
14224 Opnd_Type :=
14227 -- Deal with conversion of integer type to address if the pragma
14228 -- Allow_Integer_Address is in effect. We convert the conversion to
14229 -- an unchecked conversion in this case and we are all done.
14237 -- If we are within a child unit, check whether the type of the
14238 -- expression has an ancestor in a parent unit, in which case it
14239 -- belongs to its derivation class even if the ancestor is private.
14240 -- See RM 7.3.1 (5.2/3).
14244 -- Numeric types
14248 -- A universal fixed expression can be converted to any numeric type
14253 -- Also no need to check when in an instance or inlined body, because
14254 -- the legality has been established when the template was analyzed.
14255 -- Furthermore, numeric conversions may occur where only a private
14256 -- view of the operand type is visible at the instantiation point.
14257 -- This results in a spurious error if we check that the operand type
14258 -- is a numeric type.
14260 -- Note: in a previous version of this unit, the following tests were
14261 -- applied only for generated code (Comes_From_Source set to False),
14262 -- but in fact the test is required for source code as well, since
14263 -- this situation can arise in source code.
14268 -- Otherwise we need the conversion check
14270 else
14271 return Conversion_Check
14273 or else
14279 -- Array types
14285 then
14289 then
14293 Conversion_Error_N
14297 else
14301 -- Ada 2005 (AI-251): Internally generated conversions of access to
14302 -- interface types added to force the displacement of the pointer to
14303 -- reference the corresponding dispatch table.
14308 then
14311 -- Ada 2005 (AI-251): Anonymous access types where target references an
14312 -- interface type.
14316 E_General_Access_Type | E_Anonymous_Access_Type
14318 then
14319 -- Check the static accessibility rule of 4.6(17). Note that the
14320 -- check is not enforced when within an instance body, since the
14321 -- RM requires such cases to be caught at run time.
14323 -- If the operand is a rewriting of an allocator no check is needed
14324 -- because there are no accessibility issues.
14332 then
14333 -- In an instance, this is a run-time check, but one we know
14334 -- will fail, so generate an appropriate warning. The raise
14335 -- will be generated by Expand_N_Type_Conversion.
14339 Conversion_Error_N
14341 Operand);
14344 else
14345 Conversion_Error_N
14347 Operand);
14351 -- Special accessibility checks are needed in the case of access
14352 -- discriminants declared for a limited type.
14356 then
14357 -- When the operand is a selected access discriminant the check
14358 -- needs to be made against the level of the object denoted by
14359 -- the prefix of the selected name (Accessibility_Level handles
14360 -- checking the prefix of the operand for this case).
14363 and then Static_Accessibility_Level
14366 then
14367 -- In an instance, this is a run-time check, but one we know
14368 -- will fail, so generate an appropriate warning. The raise
14369 -- will be generated by Expand_N_Type_Conversion.
14373 Conversion_Error_N
14378 -- Real error if not in instance body
14380 else
14381 Conversion_Error_N
14388 -- The case of a reference to an access discriminant from
14389 -- within a limited type declaration (which will appear as
14390 -- a discriminal) is always illegal because the level of the
14391 -- discriminant is considered to be deeper than any (nameable)
14392 -- access type.
14396 and then
14399 then
14400 Conversion_Error_N
14402 Operand);
14410 -- General and anonymous access types
14413 E_General_Access_Type | E_Anonymous_Access_Type
14414 and then
14415 Conversion_Check
14417 and then
14419 E_Access_Subprogram_Type |
14420 E_Access_Protected_Subprogram_Type,
14422 then
14425 then
14426 Conversion_Error_N
14431 declare
14436 begin
14437 -- An extended access value may designate objects that are
14438 -- impossible to reference using a non-extended type, so
14439 -- prohibit conversions that would require being able to
14440 -- do the impossible.
14444 Conversion_Error_N
14447 Operand);
14451 -- Detect bad conversion on copy back for a view conversion
14454 Conversion_Error_N
14457 Operand);
14462 -- Check the static accessibility rule of 4.6(17). Note that the
14463 -- check is not enforced when within an instance body, since the RM
14464 -- requires such cases to be caught at run time.
14469 N_Object_Declaration
14470 then
14471 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
14472 -- conversions from an anonymous access type to a named general
14473 -- access type. Such conversions are not allowed in the case of
14474 -- access parameters and stand-alone objects of an anonymous
14475 -- access type. The implicit conversion case is recognized by
14476 -- testing that Comes_From_Source is False and that it's been
14477 -- rewritten. The Comes_From_Source test isn't sufficient because
14478 -- nodes in inlined calls to predefined library routines can have
14479 -- Comes_From_Source set to False. (Is there a better way to test
14480 -- for implicit conversions???).
14481 --
14482 -- Do not treat a rewritten 'Old attribute reference like other
14483 -- rewrite substitutions. This makes a difference, for example,
14484 -- in the case where we are generating the expansion of a
14485 -- membership test of the form
14486 -- Saooaaat'Old in Named_Access_Type
14487 -- because in this case Valid_Conversion needs to return True
14488 -- (otherwise the expansion will be False - see the call site
14489 -- in exp_ch4.adb).
14497 then
14500 -- When applying restriction No_Dynamic_Accessibility_Check,
14501 -- implicit conversions are allowed when the operand type is
14502 -- not deeper than the target type.
14507 then
14508 Conversion_Error_N
14513 -- Implicit conversions aren't allowed for objects of an
14514 -- anonymous access type, since such objects have nonstatic
14515 -- levels in Ada 2012.
14518 = N_Object_Declaration
14519 then
14520 Conversion_Error_N
14525 -- Implicit conversions aren't allowed for anonymous access
14526 -- parameters. We exclude anonymous access results as well
14527 -- as universal_access "=".
14531 N_Function_Specification |
14532 N_Procedure_Specification
14534 then
14535 Conversion_Error_N
14540 -- Detect access discriminant values that are illegal
14541 -- implicit anonymous-to-named access conversion operands.
14544 then
14545 Conversion_Error_N
14550 -- In other cases, the level of the operand's type must be
14551 -- statically less deep than that of the target type, else
14552 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
14556 then
14557 Conversion_Error_N
14564 -- Check if the operand is deeper than the target type, taking
14565 -- care to avoid the case where we are converting a result of a
14566 -- function returning an anonymous access type since the "master
14567 -- of the call" would be target type of the conversion unless
14568 -- the target type is anonymous access as well - see RM 3.10.2
14569 -- (10.3/3).
14571 -- Note that when the restriction No_Dynamic_Accessibility_Checks
14572 -- is in effect wei also want to proceed with the conversion check
14573 -- described above.
14578 /= N_Function_Specification
14582 -- Check we are not in a return value ???
14585 or else
14588 then
14589 -- In an instance, this is a run-time check, but one we know
14590 -- will fail, so generate an appropriate warning. The raise
14591 -- will be generated by Expand_N_Type_Conversion.
14595 Conversion_Error_N
14597 Operand);
14600 -- If not in an instance body, this is a real error
14602 else
14603 -- Avoid generation of spurious error message
14606 Conversion_Error_N
14608 Operand);
14614 -- Special accessibility checks are needed in the case of access
14615 -- discriminants declared for a limited type.
14619 then
14620 -- When the operand is a selected access discriminant the check
14621 -- needs to be made against the level of the object denoted by
14622 -- the prefix of the selected name (Accessibility_Level handles
14623 -- checking the prefix of the operand for this case).
14626 and then Static_Accessibility_Level
14629 then
14630 -- In an instance, this is a run-time check, but one we know
14631 -- will fail, so generate an appropriate warning. The raise
14632 -- will be generated by Expand_N_Type_Conversion.
14636 Conversion_Error_N
14641 -- If not in an instance body, this is a real error
14643 else
14644 Conversion_Error_N
14651 -- The case of a reference to an access discriminant from
14652 -- within a limited type declaration (which will appear as
14653 -- a discriminal) is always illegal because the level of the
14654 -- discriminant is considered to be deeper than any (nameable)
14655 -- access type.
14658 and then
14661 then
14662 Conversion_Error_N
14664 Operand);
14670 -- In the presence of limited_with clauses we have to use nonlimited
14671 -- views, if available.
14675 -- Helper function to handle limited views
14677 --------------------------
14678 -- Full_Designated_Type --
14679 --------------------------
14684 begin
14685 -- Handle the limited view of a type
14689 then
14691 else
14696 -- Local Declarations
14704 -- Start of processing for Check_Limited
14706 begin
14710 else
14712 Conversion_Error_NE
14717 -- Ada 2005 AI-384: legality rule is symmetric in both
14718 -- designated types. The conversion is legal (with possible
14719 -- constraint check) if either designated type is
14720 -- unconstrained.
14723 or else
14725 and then
14728 then
14729 -- Special case, if Value_Size has been used to make the
14730 -- sizes different, the conversion is not allowed even
14731 -- though the subtypes statically match.
14736 then
14737 Conversion_Error_NE
14740 Conversion_Error_NE
14745 -- Normal case where conversion is allowed
14747 else
14751 else
14752 Error_Msg_NE
14760 -- Access to subprogram types. If the operand is an access parameter,
14761 -- the type has a deeper accessibility that any master, and cannot be
14762 -- assigned. We must make an exception if the conversion is part of an
14763 -- assignment and the target is the return object of an extended return
14764 -- statement, because in that case the accessibility check takes place
14765 -- after the return.
14769 -- Note: this test of Opnd_Type is there to prevent entering this
14770 -- branch in the case of a remote access to subprogram type, which
14771 -- is internally represented as an E_Record_Type.
14774 then
14778 and then
14782 then
14783 Conversion_Error_N
14785 Operand);
14786 Conversion_Error_N
14789 Operand);
14791 Error_Msg_NE
14796 -- Check that the designated types are subtype conformant
14802 -- Check the static accessibility rule of 4.6(20)
14806 then
14807 Conversion_Error_N
14809 Operand);
14811 -- Check that if the operand type is declared in a generic body,
14812 -- then the target type must be declared within that same body
14813 -- (enforces last sentence of 4.6(20)).
14816 declare
14822 begin
14829 Conversion_Error_N
14836 -- Check that the strub modes are compatible.
14837 -- We wish to reject explicit conversions only for
14838 -- incompatible modes.
14840 return Conversion_Check
14841 (Compatible_Strub_Modes
14846 -- Remote access to subprogram types
14850 then
14851 -- It is valid to convert from one RAS type to another provided
14852 -- that their specification statically match.
14854 -- Note: at this point, remote access to subprogram types have been
14855 -- expanded to their E_Record_Type representation, and we need to
14856 -- go back to the original access type definition using the
14857 -- Corresponding_Remote_Type attribute in order to check that the
14858 -- designated profiles match.
14863 Check_Subtype_Conformant
14866 Old_Id =>
14868 Err_Loc =>
14869 N);
14871 -- Check that the strub modes are compatible.
14872 -- We wish to reject explicit conversions only for
14873 -- incompatible modes.
14875 return Conversion_Check
14876 (Compatible_Strub_Modes
14881 -- If it was legal in the generic, it's legal in the instance
14886 -- Ignore privacy for streaming or Put_Image routines
14891 then
14894 -- If both are tagged types, check legality of view conversions
14898 and then
14900 and then
14902 then
14905 -- Types derived from the same root type are convertible
14910 -- In an instance or an inlined body, there may be inconsistent views of
14911 -- the same type, or of types derived from a common root. Similarly
14912 -- for compiler-generated streaming or Put_Image subprograms.
14915 and then
14918 then
14921 -- Special check for common access type error case
14925 then
14927 Conversion_Error_NE -- CODEFIX
14931 -- Here we have a real conversion error
14933 else
14934 -- Check for missing regular with_clause when only a limited view of
14935 -- target is available.
14938 Conversion_Error_NE
14941 Conversion_Error_NE
14946 and then In_Package_Body
14947 then
14948 Conversion_Error_NE
14950 Conversion_Error_NE
14954 else
14955 Conversion_Error_NE