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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2023, 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 ------------------------------------------------------------------------------
98 -----------------------
99 -- Local Subprograms --
100 -----------------------
102 -- Second pass (top-down) type checking and overload resolution procedures
103 -- Typ is the type required by context. These procedures propagate the
104 -- type information recursively to the descendants of N. If the node is not
105 -- overloaded, its Etype is established in the first pass. If overloaded,
106 -- the Resolve routines set the correct type. For arithmetic operators, the
107 -- Etype is the base type of the context.
109 -- Note that Resolve_Attribute is separated off in Sem_Attr
111 function Has_Applicable_User_Defined_Literal
114 -- If N is a literal or a named number, check whether Typ
115 -- has a user-defined literal aspect that can apply to N.
116 -- If present, replace N with a call to the corresponding
117 -- function and return True.
120 -- Enforce the restrictions on the use of discriminants when constraining
121 -- a component of a discriminated type (record or concurrent type).
124 -- Given a node for an operator associated with type T, check that the
125 -- operator is visible. Operators all of whose operands are universal must
126 -- be checked for visibility during resolution because their type is not
127 -- determinable based on their operands.
129 procedure Check_Fully_Declared_Prefix
132 -- Check that the type of the prefix of a dereference is not incomplete
135 -- Given a call node, Call, which is known to occur immediately within the
136 -- subprogram being called, determines whether it is a detectable case of
137 -- an infinite recursion, and if so, outputs appropriate messages. Returns
138 -- True if an infinite recursion is detected, and False otherwise.
141 -- N is the node for a logical operator. If the operator is predefined, and
142 -- the root type of the operands is Standard.Boolean, then a check is made
143 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
144 -- the style check for Style_Check_Boolean_And_Or.
147 -- N is either an indexed component or a selected component. This function
148 -- returns true if the prefix denotes an atomic object that has an address
149 -- clause (the case in which we may want to issue a warning).
152 -- Determine whether E is an access type declared by an access declaration,
153 -- and not an (anonymous) allocator type.
156 -- Utility to check whether the entity for an operator is a predefined
157 -- operator, in which case the expression is left as an operator in the
158 -- tree (else it is rewritten into a call). An instance of an intrinsic
159 -- conversion operation may be given an operator name, but is not treated
160 -- like an operator. Note that an operator that is an imported back-end
161 -- builtin has convention Intrinsic, but is expected to be rewritten into
162 -- a call, so such an operator is not treated as predefined by this
163 -- predicate.
165 procedure Preanalyze_And_Resolve
169 -- Subsidiary of public versions of Preanalyze_And_Resolve.
172 -- If a default expression in entry call N depends on the discriminants
173 -- of the task, it must be replaced with a reference to the discriminant
174 -- of the task being called.
176 procedure Resolve_Dependent_Expression
180 -- Internal procedure to resolve the dependent expression Expr of the
181 -- conditional expression N with type Typ.
183 procedure Resolve_Op_Concat_Arg
188 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
189 -- concatenation operator. The operand is either of the array type or of
190 -- the component type. If the operand is an aggregate, and the component
191 -- type is composite, this is ambiguous if component type has aggregates.
194 -- Does the first part of the work of Resolve_Op_Concat
197 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
198 -- has been resolved. See Resolve_Op_Concat for details.
215 procedure Resolve_Interpolated_String_Literal
241 function Operator_Kind
244 -- Utility to map the name of an operator into the corresponding Node. Used
245 -- by other node rewriting procedures.
248 -- Resolve actuals of call, and add default expressions for missing ones.
249 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
250 -- called subprogram.
253 -- Called from Resolve_Call, when the prefix denotes an entry or element
254 -- of entry family. Actuals are resolved as for subprograms, and the node
255 -- is rebuilt as an entry call. Also called for protected operations. Typ
256 -- is the context type, which is used when the operation is a protected
257 -- function with no arguments, and the return value is indexed.
260 -- Called when P is the prefix of an indexed component, or of a selected
261 -- component, or of a slice. If P is of an access type, we unconditionally
262 -- rewrite it as an explicit dereference. This ensures that the expander
263 -- and the code generator have a fully explicit tree to work with.
266 -- A call to a user-defined intrinsic operator is rewritten as a call to
267 -- the corresponding predefined operator, with suitable conversions. Note
268 -- that this applies only for intrinsic operators that denote predefined
269 -- operators, not ones that are intrinsic imports of back-end builtins.
272 -- Ditto, for arithmetic unary operators
275 -- If an operator node resolves to a call to a user-defined operator,
276 -- rewrite the node as a function call.
278 procedure Make_Call_Into_Operator
282 -- Inverse transformation: if an operator is given in functional notation,
283 -- then after resolving the node, transform into an operator node, so that
284 -- operands are resolved properly. Recall that predefined operators do not
285 -- have a full signature and special resolution rules apply.
287 procedure Rewrite_Renamed_Operator
291 -- An operator can rename another, e.g. in an instantiation. In that
292 -- case, the proper operator node must be constructed and resolved.
295 -- The String_Literal_Subtype is built for all strings that are not
296 -- operands of a static concatenation operation. If the argument is not
297 -- a N_String_Literal node, then the call has no effect.
300 -- Build subtype of array type, with the range specified by the slice
303 -- Called after N has been resolved and evaluated, but before range checks
304 -- have been applied. This rewrites the conversion into a simpler form.
306 function Try_User_Defined_Literal
309 -- If an operator node has a literal operand, check whether the type
310 -- of the context, or the type of the other operand has a user-defined
311 -- literal aspect that can be applied to the literal to resolve the node.
312 -- If such aspect exists, replace literal with a call to the
313 -- corresponding function and return True, return false otherwise.
316 -- A universal_fixed expression in an universal context is unambiguous if
317 -- there is only one applicable fixed point type. Determining whether there
318 -- is only one requires a search over all visible entities, and happens
319 -- only in very pathological cases (see 6115-006).
321 -------------------------
322 -- Ambiguous_Character --
323 -------------------------
328 begin
332 -- First the ones in Standard
337 -- Include Wide_Wide_Character in Ada 2005 mode
343 -- Now any other types that match
353 -------------------------
354 -- Analyze_And_Resolve --
355 -------------------------
358 begin
364 begin
369 -- Versions with check(s) suppressed
371 procedure Analyze_And_Resolve
375 is
378 begin
380 declare
382 begin
388 else
389 declare
391 begin
399 and then Scope_Is_Transient
400 then
401 -- This can only happen if a transient scope was created for an inner
402 -- expression, which will be removed upon completion of the analysis
403 -- of an enclosing construct. The transient scope must have the
404 -- suppress status of the enclosing environment, not of this Analyze
405 -- call.
408 Scope_Suppress;
412 procedure Analyze_And_Resolve
415 is
418 begin
420 declare
422 begin
428 else
429 declare
431 begin
440 Scope_Suppress;
444 -------------------------------------
445 -- Has_Applicable_User_Defined_Literal --
446 -------------------------------------
448 function Has_Applicable_User_Defined_Literal
451 is
453 Literal_Aspect_Map :
474 begin
476 and then Present
478 or else
481 and then
482 Present
483 (Find_Aspect
485 then
486 Lit_Aspect :=
490 Callee :=
497 then
498 Callee :=
499 Corresponding_Primitive_Op
504 -- Handle an identifier that denotes a named number.
511 Start_String;
512 Store_String_Chars
517 else
519 Start_String;
525 Store_String_Chars
529 -- Note: Set_Etype is called below on Param1
532 Start_String;
533 Store_String_Chars
542 else
543 Error_Msg_NE
553 else
554 Param1 :=
555 Make_String_Literal
560 Call :=
561 Make_Function_Call
571 else
577 -- Conversion not needed if the result type of the call is class-wide
578 -- or if the result type matches the context type.
582 then
583 -- Conversion may be needed in case of an inherited
584 -- aspect of a derived type. For a null extension, we
585 -- use a null extension aggregate instead because the
586 -- downward type conversion would be illegal.
588 if Is_Null_Extension_Of
591 then
595 else
604 else
609 ----------------------------
610 -- Check_Discriminant_Use --
611 ----------------------------
619 begin
620 -- Any use in a spec-expression is legal
627 -- Discriminant cannot be used to constrain a scalar type
634 then
639 -- The following check catches the unusual case where a
640 -- discriminant appears within an index constraint that is part
641 -- of a larger expression within a constraint on a component,
642 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
643 -- check case of record components, and note that a similar check
644 -- should also apply in the case of discriminant constraints
645 -- below. ???
647 -- Note that the check for N_Subtype_Declaration below is to
648 -- detect the valid use of discriminants in the constraints of a
649 -- subtype declaration when this subtype declaration appears
650 -- inside the scope of a record type (which is syntactically
651 -- illegal, but which may be created as part of derived type
652 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
653 -- for more info.
657 and then not
659 and then
661 | N_Subtype_Declaration
663 then
664 Error_Msg_N
669 -- Detect a common error:
671 -- type R (D : Positive := 100) is record
672 -- Name : String (1 .. D);
673 -- end record;
675 -- The default value causes an object of type R to be allocated
676 -- with room for Positive'Last characters. The RM does not mandate
677 -- the allocation of the maximum size, but that is what GNAT does
678 -- so we should warn the programmer that there is a problem.
687 -- Return True if type T has a large enough range that any
688 -- array whose index type covered the whole range of the type
689 -- would likely raise Storage_Error.
691 ------------------------
692 -- Large_Storage_Type --
693 ------------------------
696 begin
697 -- The type is considered large if its bounds are known at
698 -- compile time and if it requires at least as many bits as
699 -- a Positive to store the possible values.
703 and then
708 -- Start of processing for Check_Large
710 begin
711 -- Check that the Disc has a large range
717 -- If the enclosing type is limited, we allocate only the
718 -- default value, not the maximum, and there is no need for
719 -- a warning.
725 -- Check that it is the high bound
729 then
733 -- Check the array allows a large range at this bound. First
734 -- find the array
748 -- Next, find the dimension
756 loop
765 -- Now, check the dimension has a large range
771 -- Warn about the danger
773 Error_Msg_N
783 -- Legal case is in index or discriminant constraint
786 | N_Discriminant_Association
787 then
789 Error_Msg_N
794 then
795 Error_Msg_N
801 -- Otherwise, context is an expression. It should not be within (i.e. a
802 -- subexpression of) a constraint for a component.
804 else
808 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
809 loop
815 -- If the discriminant is used in an expression that is a bound of a
816 -- scalar type, an Itype is created and the bounds are attached to
817 -- its range, not to the original subtype indication. Such use is of
818 -- course a double fault.
822 | N_Derived_Type_Definition
825 -- The constraint itself may be given by a subtype indication,
826 -- rather than by a more common discrete range.
829 and then
833 then
834 Error_Msg_N
840 --------------------------------
841 -- Check_For_Visible_Operator --
842 --------------------------------
845 begin
849 then
850 Error_Msg_NE -- CODEFIX
852 Error_Msg_N -- CODEFIX
857 ---------------------------------
858 -- Check_Fully_Declared_Prefix --
859 ---------------------------------
861 procedure Check_Fully_Declared_Prefix
864 is
865 begin
866 -- Check that the designated type of the prefix of a dereference is
867 -- not an incomplete type. This cannot be done unconditionally, because
868 -- dereferences of private types are legal in default expressions. This
869 -- case is taken care of in Check_Fully_Declared, called below. There
870 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
872 -- This consideration also applies to similar checks for allocators,
873 -- qualified expressions, and type conversions.
875 -- An additional exception concerns other per-object expressions that
876 -- are not directly related to component declarations, in particular
877 -- representation pragmas for tasks. These will be per-object
878 -- expressions if they depend on discriminants or some global entity.
879 -- If the task has access discriminants, the designated type may be
880 -- incomplete at the point the expression is resolved. This resolution
881 -- takes place within the body of the initialization procedure, where
882 -- the discriminant is replaced by its discriminal.
886 then
889 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
890 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
891 -- Analyze_Object_Renaming, and Freeze_Entity.
897 E_Incomplete_Type
899 then
901 else
906 ------------------------------
907 -- Check_Infinite_Recursion --
908 ------------------------------
912 -- Determine whether call N invokes the related enclosing subprogram
913 -- with actuals that differ from the subprogram's formals.
916 -- Determine whether arbitrary node N denotes a conditional construct
919 -- Determine whether arbitrary node N denotes a control flow statement
920 -- or a construct that may contains such a statement.
923 -- Determine whether arbitrary node N appears immediately within the
924 -- statements of an entry or subprogram body.
927 -- Determine whether arbitrary node N appears immediately within the
928 -- body of an entry or subprogram, and is preceded by a single raise
929 -- statement.
932 -- Determine whether arbitrary node N denotes a raise statement
935 -- Determine whether arbitrary node N is the sole source statement in
936 -- the body of the enclosing subprogram.
939 -- Determine whether arbitrary node N is preceded by a control flow
940 -- statement.
943 -- Determine whether arbitrary node N appears within a conditional
944 -- construct.
946 --------------------------------------
947 -- Invoked_With_Different_Arguments --
948 --------------------------------------
956 begin
957 -- Determine whether the formals of the invoked subprogram are not
958 -- used as actuals in the call.
964 -- The current actual does not match the current formal
968 then
979 ------------------------------
980 -- Is_Conditional_Statement --
981 ------------------------------
984 begin
985 return
987 | N_Case_Expression
988 | N_Case_Statement
989 | N_If_Expression
990 | N_If_Statement
991 | N_Or_Else;
994 -------------------------------
995 -- Is_Control_Flow_Statement --
996 -------------------------------
999 begin
1000 -- It is assumed that all statements may affect the control flow in
1001 -- some way. A raise statement may be expanded into a non-statement
1002 -- node.
1007 --------------------------------
1008 -- Is_Immediately_Within_Body --
1009 --------------------------------
1014 begin
1015 return
1022 --------------------
1023 -- Is_Raise_Idiom --
1024 --------------------
1030 begin
1033 -- Assume that no raise statement has been seen yet
1037 -- Examine the statements preceding the input node, skipping
1038 -- internally-generated constructs.
1043 -- Multiple raise statements violate the idiom
1059 -- At this point the node must be preceded by a raise statement,
1060 -- and the raise statement has to be the sole statement within
1061 -- the enclosing entry or subprogram body.
1063 return
1070 ------------------------
1071 -- Is_Raise_Statement --
1072 ------------------------
1075 begin
1076 -- A raise statement may be transfomed into a Raise_xxx_Error node
1078 return
1083 -----------------------
1084 -- Is_Sole_Statement --
1085 -----------------------
1090 begin
1091 -- The input node appears within the statements of an entry or
1092 -- subprogram body. Examine the statements preceding the node.
1099 -- The statement is preceded by another statement or a source
1100 -- construct. This indicates that the node does not appear by
1101 -- itself.
1105 then
1115 -- The input node is within a construct nested inside the entry or
1116 -- subprogram body.
1121 ----------------------------------------
1122 -- Preceded_By_Control_Flow_Statement --
1123 ----------------------------------------
1125 function Preceded_By_Control_Flow_Statement
1127 is
1130 begin
1134 -- Examine the statements preceding the input node
1147 -- Assume that the node is part of some control flow statement
1152 ----------------------------------
1153 -- Within_Conditional_Statement --
1154 ----------------------------------
1159 begin
1165 -- Prevent the search from going too far
1177 -- Local variables
1182 -- Start of processing for Check_Infinite_Recursion
1184 begin
1185 -- The call is assumed to be safe when the enclosing subprogram is
1186 -- invoked with actuals other than its formals.
1187 --
1188 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1189 -- begin
1190 -- ...
1191 -- Proc (A1, A2, ..., AN);
1192 -- ...
1193 -- end Proc;
1198 -- The call is assumed to be safe when the invocation of the enclosing
1199 -- subprogram depends on a conditional statement.
1200 --
1201 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1202 -- begin
1203 -- ...
1204 -- if Some_Condition then
1205 -- Proc (F1, F2, ..., FN);
1206 -- end if;
1207 -- ...
1208 -- end Proc;
1213 -- The context of the call is assumed to be safe when the invocation of
1214 -- the enclosing subprogram is preceded by some control flow statement.
1215 --
1216 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1217 -- begin
1218 -- ...
1219 -- if Some_Condition then
1220 -- ...
1221 -- end if;
1222 -- ...
1223 -- Proc (F1, F2, ..., FN);
1224 -- ...
1225 -- end Proc;
1230 -- Detect an idiom where the context of the call is preceded by a single
1231 -- raise statement.
1232 --
1233 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1234 -- begin
1235 -- raise ...;
1236 -- Proc (F1, F2, ..., FN);
1237 -- end Proc;
1243 -- At this point it is certain that infinite recursion will take place
1244 -- as long as the call is executed. Detect a case where the context of
1245 -- the call is the sole source statement within the subprogram body.
1246 --
1247 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1248 -- begin
1249 -- Proc (F1, F2, ..., FN);
1250 -- end Proc;
1251 --
1252 -- Install an explicit raise to prevent the infinite recursion.
1263 -- Otherwise infinite recursion could take place, considering other flow
1264 -- control constructs such as gotos, exit statements, etc.
1266 else
1275 ---------------------------------------
1276 -- Check_No_Direct_Boolean_Operators --
1277 ---------------------------------------
1280 begin
1283 then
1284 -- Restriction only applies to original source code
1291 -- Do style check (but skip if in instance, error is on template)
1300 ------------------------------
1301 -- Check_Parameterless_Call --
1302 ------------------------------
1308 -- If the prefix is of an access_to_subprogram type, the node must be
1309 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1310 -- interpretations are access to subprograms.
1312 ---------------------------
1313 -- Prefix_Is_Access_Subp --
1314 ---------------------------
1320 begin
1321 -- If the context is an attribute reference that can apply to
1322 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1326 in Name_Address | Name_Code_Address | Name_Access
1327 then
1332 return
1335 else
1340 then
1351 -- Start of processing for Check_Parameterless_Call
1353 begin
1354 -- Defend against junk stuff if errors already detected
1361 then
1368 -- If the context expects a value, and the name is a procedure, this is
1369 -- most likely a missing 'Access. Don't try to resolve the parameterless
1370 -- call, error will be caught when the outer call is analyzed.
1375 and then
1377 | N_Function_Call
1378 | N_Procedure_Call_Statement
1379 then
1383 -- Rewrite as call if overloadable entity that is (or could be, in the
1384 -- overloaded case) a function call. If we know for sure that the entity
1385 -- is an enumeration literal, we do not rewrite it.
1387 -- If the entity is the name of an operator, it cannot be a call because
1388 -- operators cannot have default parameters. In this case, this must be
1389 -- a string whose contents coincide with an operator name. Set the kind
1390 -- of the node appropriately.
1398 -- Rewrite as call if it is an explicit dereference of an expression of
1399 -- a subprogram access type, and the subprogram type is not that of a
1400 -- procedure or entry.
1402 or else
1405 -- Rewrite as call if it is a selected component which is a function,
1406 -- this is the case of a call to a protected function (which may be
1407 -- overloaded with other protected operations).
1409 or else
1412 or else
1414 E_Entry | E_Procedure
1417 -- If one of the above three conditions is met, rewrite as call. Apply
1418 -- the rewriting only once.
1420 then
1423 then
1425 -- This may be a prefixed call that was not fully analyzed, e.g.
1426 -- an actual in an instance.
1431 then
1439 -- The node is the name of the parameterless call. Preserve its
1440 -- descendants, which may be complex expressions.
1444 -- If overloaded, overload set belongs to new copy
1448 -- Change node to parameterless function call (note that the
1449 -- Parameter_Associations associations field is left set to Empty,
1450 -- its normal default value since there are no parameters)
1470 --------------------------------
1471 -- Is_Atomic_Ref_With_Address --
1472 --------------------------------
1477 begin
1481 else
1482 declare
1485 begin
1493 -----------------------------
1494 -- Is_Definite_Access_Type --
1495 -----------------------------
1499 begin
1505 ----------------------
1506 -- Is_Predefined_Op --
1507 ----------------------
1510 begin
1511 -- Predefined operators are intrinsic subprograms
1517 -- A call to a back-end builtin is never a predefined operator
1528 -----------------------------
1529 -- Make_Call_Into_Operator --
1530 -----------------------------
1532 procedure Make_Call_Into_Operator
1536 is
1551 -- If the operand is not universal, and the operator is given by an
1552 -- expanded name, verify that the operand has an interpretation with a
1553 -- type defined in the given scope of the operator.
1556 -- Find a type of the given class in package Pack that contains the
1557 -- operator.
1559 ---------------------------
1560 -- Operand_Type_In_Scope --
1561 ---------------------------
1568 begin
1572 else
1586 ---------------
1587 -- Type_In_P --
1588 ---------------
1594 -- Verify that node is not part of the type declaration for the
1595 -- candidate type, which would otherwise be invisible.
1597 -------------
1598 -- In_Decl --
1599 -------------
1605 begin
1614 else
1617 loop
1620 else
1629 -- Start of processing for Type_In_P
1631 begin
1632 -- If the context type is declared in the prefix package, this is the
1633 -- desired base type.
1638 else
1652 -- Start of processing for Make_Call_Into_Operator
1654 begin
1657 -- Preserve the Comes_From_Source flag on the result if the original
1658 -- call came from source. Although it is not strictly the case that the
1659 -- operator as such comes from the source, logically it corresponds
1660 -- exactly to the function call in the source, so it should be marked
1661 -- this way (e.g. to make sure that validity checks work fine).
1665 -- Ensure that the corresponding operator has the same parent as the
1666 -- original call. This guarantees that parent traversals performed by
1667 -- the ABE mechanism succeed.
1671 -- Binary operator
1681 -- Unary operator
1683 else
1689 -- If the operator is denoted by an expanded name, and the prefix is
1690 -- not Standard, but the operator is a predefined one whose scope is
1691 -- Standard, then this is an implicit_operator, inserted as an
1692 -- interpretation by the procedure of the same name. This procedure
1693 -- overestimates the presence of implicit operators, because it does
1694 -- not examine the type of the operands. Verify now that the operand
1695 -- type appears in the given scope. If right operand is universal,
1696 -- check the other operand. In the case of concatenation, either
1697 -- argument can be the component type, so check the type of the result.
1698 -- If both arguments are literals, look for a type of the right kind
1699 -- defined in the given scope. This elaborate nonsense is brought to
1700 -- you courtesy of b33302a. The type itself must be frozen, so we must
1701 -- find the type of the proper class in the given scope.
1703 -- A final wrinkle is the multiplication operator for fixed point types,
1704 -- which is defined in Standard only, and not in the scope of the
1705 -- fixed point type itself.
1710 -- If this is a package renaming, get renamed entity, which will be
1711 -- the scope of the operands if operaton is type-correct.
1717 -- If the entity being called is defined in the given package, it is
1718 -- a renaming of a predefined operator, and known to be legal.
1722 then
1725 -- Visibility does not need to be checked in an instance: if the
1726 -- operator was not visible in the generic it has been diagnosed
1727 -- already, else there is an implicit copy of it in the instance.
1735 then
1740 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1741 -- available.
1747 then
1750 else
1759 and then Is_Binary
1761 then
1767 -- Verify that the scope contains a type that corresponds to
1768 -- the given literal. Optimize the case where Pack is Standard.
1789 else
1798 else
1807 then
1810 -- If the type is defined elsewhere, and the operator is not
1811 -- defined in the given scope (by a renaming declaration, e.g.)
1812 -- then this is an error as well. If an extension of System is
1813 -- present, and the type may be defined there, Pack must be
1814 -- System itself.
1821 then
1824 else
1830 then
1837 Error_Msg_NE
1842 -- Detect a mismatch between the context type and the result type
1843 -- in the named package, which is otherwise not detected if the
1844 -- operands are universal. Check is only needed if source entity is
1845 -- an operator, not a function that renames an operator.
1852 and then not In_Instance
1853 then
1856 then
1857 -- Already checked above
1861 -- Operator may be defined in an extension of System
1866 then
1869 else
1870 -- Could we use Wrong_Type here??? (this would require setting
1871 -- Etype (N) to the actual type found where Typ was expected).
1882 else
1886 -- If this is a call to a function that renames a predefined equality,
1887 -- the renaming declaration provides a type that must be used to
1888 -- resolve the operands. This must be done now because resolution of
1889 -- the equality node will not resolve any remaining ambiguity, and it
1890 -- assumes that the first operand is not overloaded.
1895 then
1905 -- If this is an arithmetic operator and the result type is private,
1906 -- the operands and the result must be wrapped in conversion to
1907 -- expose the underlying numeric type and expand the proper checks,
1908 -- e.g. on division.
1912 when N_Op_Add
1913 | N_Op_Divide
1914 | N_Op_Expon
1915 | N_Op_Mod
1916 | N_Op_Multiply
1917 | N_Op_Rem
1918 | N_Op_Subtract
1919 =>
1922 when N_Op_Abs
1923 | N_Op_Minus
1924 | N_Op_Plus
1925 =>
1931 else
1936 -------------------
1937 -- Operator_Kind --
1938 -------------------
1940 function Operator_Kind
1943 is
1946 begin
1947 -- Use CASE statement or array???
1984 else
1988 -- Unary operators
1990 else
1999 else
2007 ----------------------------
2008 -- Preanalyze_And_Resolve --
2009 ----------------------------
2011 procedure Preanalyze_And_Resolve
2015 is
2019 Inside_Preanalysis_Without_Freezing;
2020 begin
2025 Inside_Preanalysis_Without_Freezing :=
2032 -- See also Preanalyze_And_Resolve in sem.adb for similar handling
2034 -- Normally, we suppress all checks for this preanalysis. There is no
2035 -- point in processing them now, since they will be applied properly
2036 -- and in the proper location when the default expressions reanalyzed
2037 -- and reexpanded later on. We will also have more information at that
2038 -- point for possible suppression of individual checks.
2040 -- However, in GNATprove mode, most expansion is suppressed, and this
2041 -- later reanalysis and reexpansion may not occur. GNATprove mode does
2042 -- require the setting of checking flags for proof purposes, so we
2043 -- do the GNATprove preanalysis without suppressing checks.
2045 -- This special handling for SPARK mode is required for example in the
2046 -- case of Ada 2012 constructs such as quantified expressions, which are
2047 -- expanded in two separate steps.
2049 -- We also do not want to suppress checks if we are not dealing
2050 -- with a default expression. One such case that is known to reach
2051 -- this point is the expression of an expression function.
2055 else
2059 Expander_Mode_Restore;
2064 Inside_Preanalysis_Without_Freezing :=
2068 pragma Assert
2072 ----------------------------
2073 -- Preanalyze_And_Resolve --
2074 ----------------------------
2077 begin
2081 -- Version without context type
2086 begin
2093 Expander_Mode_Restore;
2097 ------------------------------------------
2098 -- Preanalyze_With_Freezing_And_Resolve --
2099 ------------------------------------------
2101 procedure Preanalyze_With_Freezing_And_Resolve
2104 is
2105 begin
2109 ----------------------------------
2110 -- Replace_Actual_Discriminants --
2111 ----------------------------------
2118 -- Comment needed???
2120 -------------------
2121 -- Process_Discr --
2122 -------------------
2127 begin
2133 then
2149 -- Start of processing for Replace_Actual_Discriminants
2151 begin
2155 -- Allow the replacement of concurrent discriminants in GNATprove even
2156 -- though this is a light expansion activity. Note that generic units
2157 -- are not modified.
2162 else
2178 -------------
2179 -- Resolve --
2180 -------------
2196 -- Determine whether a node comes from a predefined library unit or
2197 -- Standard.
2200 -- Try and fix up a literal so that it matches its expected type. New
2201 -- literals are manufactured if necessary to avoid cascaded errors.
2204 -- Additional diagnostics when an ambiguous call has an ambiguous
2205 -- argument (typically a controlling actual).
2208 -- Called when attempt at resolving current expression fails
2210 ------------------------------------
2211 -- Comes_From_Predefined_Lib_Unit --
2212 -------------------------------------
2215 begin
2216 return
2220 --------------------
2221 -- Patch_Up_Value --
2222 --------------------
2225 begin
2242 then
2247 Char_Literal_Value =>
2263 -------------------------------
2264 -- Report_Ambiguous_Argument --
2265 -------------------------------
2272 begin
2276 then
2279 -- Examine possible interpretations, and adapt the message
2280 -- for inherited subprograms declared by a type derivation.
2288 else
2296 -- Additional message and hint if the ambiguity involves an Ada 2022
2297 -- container aggregate.
2302 -----------------------
2303 -- Resolution_Failed --
2304 -----------------------
2307 begin
2310 -- Set the type to the desired one to minimize cascaded errors. Note
2311 -- that this is an approximation and does not work in all cases.
2318 -- The caller will return without calling the expander, so we need
2319 -- to set the analyzed flag. Note that it is fine to set Analyzed
2320 -- to True even if we are in the middle of a shallow analysis,
2321 -- (see the spec of sem for more details) since this is an error
2322 -- situation anyway, and there is no point in repeating the
2323 -- analysis later (indeed it won't work to repeat it later, since
2324 -- we haven't got a clear resolution of which entity is being
2325 -- referenced.)
2331 -- Start of processing for Resolve
2333 begin
2338 -- Access attribute on remote subprogram cannot be used for a non-remote
2339 -- access-to-subprogram type.
2343 | Name_Unrestricted_Access
2344 | Name_Unchecked_Access
2350 then
2351 Error_Msg_N
2355 -- If the context is a Remote_Access_To_Subprogram, access attributes
2356 -- must be resolved with the corresponding fat pointer. There is no need
2357 -- to check for the attribute name since the return type of an
2358 -- attribute is never a remote type.
2363 then
2364 declare
2372 begin
2373 -- Check that Typ is a remote access-to-subprogram type
2377 -- Prefix (N) must statically denote a remote subprogram
2378 -- declared in a package specification.
2382 Attr = Attribute_Unrestricted_Access
2383 then
2398 or else
2400 then
2402 Error_Msg_N
2404 N);
2407 -- If we are generating code in distributed mode, perform
2408 -- semantic checks against corresponding remote entities.
2410 if Expander_Active
2412 then
2413 Check_Subtype_Conformant
2415 Old_Id => Designated_Type
2441 then
2446 -- Return if already analyzed
2453 -- Any case of Any_Type as the Etype value means that we had a
2454 -- previous error.
2463 -- The resolution of an Expression_With_Actions is determined by
2464 -- its Expression, but if the node comes from source it is a
2465 -- Declare_Expression and requires scope management.
2470 else
2477 -- The resolution of a conditional expression that is the operand of a
2478 -- type conversion is determined by the conversion (RM 4.5.7(10/3)).
2482 then
2486 -- If not overloaded, then we know the type, and all that needs doing
2487 -- is to check that this type is compatible with the context.
2493 -- In the overloaded case, we must select the interpretation that
2494 -- is compatible with the context (i.e. the type passed to Resolve)
2496 else
2499 -- Loop through possible interpretations
2508 -- We are only interested in interpretations that are compatible
2509 -- with the expected type, any other interpretations are ignored.
2514 Write_Eol;
2517 else
2518 -- Skip the current interpretation if it is disabled by an
2519 -- abstract operator. This action is performed only when the
2520 -- type against which we are resolving is the same as the
2521 -- type of the interpretation.
2527 then
2535 -- First matching interpretation
2543 -- Matching interpretation that is not the first, maybe an
2544 -- error, but there are some cases where preference rules are
2545 -- used to choose between the two possibilities. These and
2546 -- some more obscure cases are handled in Disambiguate.
2548 else
2549 -- If the current statement is part of a predefined library
2550 -- unit, then all interpretations which come from user level
2551 -- packages should not be considered. Check previous and
2552 -- current one.
2560 -- Previous interpretation must be discarded
2570 -- Otherwise apply further disambiguation steps
2575 -- Disambiguation has succeeded. Skip the remaining
2576 -- interpretations.
2586 else
2587 -- Before we issue an ambiguity complaint, check for the
2588 -- case of a subprogram call where at least one of the
2589 -- arguments is Any_Type, and if so suppress the message,
2590 -- since it is a cascaded error. This can also happen for
2591 -- a generalized indexing operation.
2596 then
2597 declare
2601 begin
2617 Write_Eol;
2630 then
2635 then
2639 -- Not that special case, so issue message using the flag
2640 -- Ambiguous to control printing of the header message
2641 -- only at the start of an ambiguous set.
2646 then
2647 Error_Msg_N
2650 else
2651 Error_Msg_NE -- CODEFIX
2659 Error_Msg_N
2661 else
2662 Error_Msg_N -- CODEFIX
2668 then
2669 Report_Ambiguous_Argument;
2675 -- By default, the error message refers to the candidate
2676 -- interpretation. But if it is a predefined operator, it
2677 -- is implicitly declared at the declaration of the type
2678 -- of the operand. Recover the sloc of that declaration
2679 -- for the error message.
2685 Standard_Standard
2686 then
2691 then
2699 Standard_Standard
2700 then
2705 then
2709 -- If this is an indirect call, use the subprogram_type
2710 -- in the message, to have a meaningful location. Also
2711 -- indicate if this is an inherited operation, created
2712 -- by a type declaration.
2717 then
2719 Error_Msg_Sloc :=
2721 else
2728 then
2729 -- Special-case the message for universal_fixed
2730 -- operators, which are not declared with the type
2731 -- of the operand, but appear forever in Standard.
2735 then
2736 Error_Msg_N
2739 else
2740 Error_Msg_N
2744 elsif
2746 then
2747 Error_Msg_N
2749 else
2750 Error_Msg_N -- CODEFIX
2757 -- We have a matching interpretation, Expr_Type is the type
2758 -- from this interpretation, and Seen is the entity.
2760 -- For an operator, just set the entity name. The type will be
2761 -- set by the specific operator resolution routine.
2768 | N_Character_Literal
2769 | N_Delta_Aggregate
2770 | N_If_Expression
2771 then
2774 -- AI05-0139-2: Expression is overloaded because type has
2775 -- implicit dereference. The context may be the one that
2776 -- requires implicit dereferemce.
2782 -- If the expression is an entity, generate a reference
2783 -- to it, as this is not done for an overloaded construct
2784 -- during analysis.
2788 then
2791 -- Examine access discriminants of entity type,
2792 -- to check whether one of them yields the
2793 -- expected type.
2795 declare
2799 begin
2820 then
2821 -- If the node is a general indexing, the dereference is
2822 -- is inserted when resolving the rewritten form, else
2823 -- insert it now.
2827 then
2831 -- For an explicit dereference, attribute reference, range,
2832 -- short-circuit form (which is not an operator node), or call
2833 -- with a name that is an explicit dereference, there is
2834 -- nothing to be done at this point.
2837 | N_And_Then
2838 | N_Explicit_Dereference
2839 | N_Identifier
2840 | N_Indexed_Component
2841 | N_Or_Else
2842 | N_Range
2843 | N_Selected_Component
2844 | N_Slice
2846 then
2849 -- For procedure or function calls, set the type of the name,
2850 -- and also the entity pointer for the prefix.
2854 then
2861 then
2866 -- For all other cases, just set the type of the Name
2868 else
2876 -- Move to next interpretation
2884 -- At this stage Found indicates whether or not an acceptable
2885 -- interpretation exists. If not, then we have an error, except that if
2886 -- the context is Any_Type as a result of some other error, then we
2887 -- suppress the error report.
2892 -- If type we are looking for is Void, then this is the procedure
2893 -- call case, and the error is simply that what we gave is not a
2894 -- procedure name (we think of procedure calls as expressions with
2895 -- types internally, but the user doesn't think of them this way).
2899 -- Special case message if function used as a procedure
2904 then
2905 Error_Msg_NE
2908 Error_Msg_N
2912 -- Otherwise give general message (not clear what cases this
2913 -- covers, but no harm in providing for them).
2915 else
2921 -- Otherwise we do have a subexpression with the wrong type
2923 -- Check for the case of an allocator which uses an access type
2924 -- instead of the designated type. This is a common error and we
2925 -- specialize the message, posting an error on the operand of the
2926 -- allocator, complaining that we expected the designated type of
2927 -- the allocator.
2933 then
2937 -- Check for view mismatch on Null in instances, for which the
2938 -- view-swapping mechanism has no identifier.
2944 then
2949 -- Check for an aggregate. Sometimes we can get bogus aggregates
2950 -- from misuse of parentheses, and we are about to complain about
2951 -- the aggregate without even looking inside it.
2953 -- Instead, if we have an aggregate of type Any_Composite, then
2954 -- analyze and resolve the component fields, and then only issue
2955 -- another message if we get no errors doing this (otherwise
2956 -- assume that the errors in the aggregate caused the problem).
2960 then
2963 then
2972 -- Disable expansion in any case. If there is a type mismatch
2973 -- it may be fatal to try to expand the aggregate. The flag
2974 -- would otherwise be set to false when the error is posted.
2978 declare
2980 -- Check one aggregate, and set Found to True if we have a
2981 -- definite error in any of its elements
2984 -- Check one element of aggregate and set Found to True if
2985 -- we definitely have an error in the element.
2987 ----------------
2988 -- Check_Aggr --
2989 ----------------
2994 begin
3007 -- If this is a default-initialized component, then
3008 -- there is nothing to check. The box will be
3009 -- replaced by the appropriate call during late
3010 -- expansion.
3014 then
3023 ----------------
3024 -- Check_Elmt --
3025 ----------------
3028 begin
3029 -- If we have a nested aggregate, go inside it (to
3030 -- attempt a naked analyze-resolve of the aggregate can
3031 -- cause undesirable cascaded errors). Do not resolve
3032 -- expression if it needs a type from context, as for
3033 -- integer * fixed expression.
3038 else
3043 then
3053 begin
3058 -- If node is a literal and context type has a user-defined
3059 -- literal aspect, rewrite node as a call to the corresponding
3060 -- function, which plays the role of an implicit conversion.
3063 N_Numeric_Or_String_Literal | N_Identifier
3065 then
3070 -- Looks like we have a type error, but check for special case
3071 -- of Address wanted, integer found, with the configuration pragma
3072 -- Allow_Integer_Address active. If we have this case, introduce
3073 -- an unchecked conversion to allow the integer expression to be
3074 -- treated as an Address. The reverse case of integer wanted,
3075 -- Address found, is treated in an analogous manner.
3082 -- Under relaxed RM semantics silently replace occurrences of null
3083 -- by System.Null_Address.
3091 -- That special Allow_Integer_Address check did not apply, so we
3092 -- have a real type error. If an error message was issued already,
3093 -- Found got reset to True, so if it's still False, issue standard
3094 -- Wrong_Type message.
3098 declare
3101 begin
3107 -- Protected operation: retrieve operation name
3111 else
3116 Error_Msg_NE
3122 declare
3126 begin
3133 Error_Msg_NE
3139 else
3143 -- Recognize the case of a quantified expression being mistaken
3144 -- for an iterated component association because the user
3145 -- forgot the "all" or "some" keyword after "for". Because the
3146 -- error message starts with "missing ALL", we automatically
3147 -- benefit from the associated CODEFIX, which requires that
3148 -- the message is located on the identifier following "for"
3149 -- in order for the CODEFIX to insert "all" in the right place.
3154 = N_Iterated_Component_Association
3156 then
3157 if Present
3158 (Iterator_Specification
3160 then
3161 Error_Msg_N -- CODEFIX
3163 Defining_Identifier
3164 (Iterator_Specification
3166 else
3167 Error_Msg_N -- CODEFIX
3169 Defining_Identifier
3173 -- For an operator with no interpretation, check whether
3174 -- one of its operands may be a user-defined literal.
3178 then
3181 else
3187 Resolution_Failed;
3190 -- Test if we have more than one interpretation for the context
3193 Resolution_Failed;
3196 -- Only one interpretation
3198 else
3199 -- Prevent implicit conversions between access-to-subprogram types
3200 -- with different strub modes. Explicit conversions are acceptable in
3201 -- some circumstances. We don't have to be concerned about data or
3202 -- access-to-data types. Conversions between data types can safely
3203 -- drop or add strub attributes from types, because strub effects are
3204 -- associated with the locations rather than values. E.g., converting
3205 -- a hypothetical Strub_Integer variable to Integer would load the
3206 -- value from the variable, enabling stack scrabbing for the
3207 -- enclosing subprogram, and then convert the value to Integer. As
3208 -- for conversions between access-to-data types, that's no different
3209 -- from any other case of type punning.
3215 then
3216 Check_Same_Strub_Mode
3220 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3221 -- the "+" on T is abstract, and the operands are of universal type,
3222 -- the above code will have (incorrectly) resolved the "+" to the
3223 -- universal one in Standard. Therefore check for this case and give
3224 -- an error. We can't do this earlier, because it would cause legal
3225 -- cases to get errors (when some other type has an abstract "+").
3231 then
3236 then
3237 Nondispatching_Call_To_Abstract_Operation
3246 -- Here we have an acceptable interpretation for the context
3248 -- Propagate type information and normalize tree for various
3249 -- predefined operations. If the context only imposes a class of
3250 -- types, rather than a specific type, propagate the actual type
3251 -- downward.
3257 Typ = Any_Discrete
3258 then
3261 -- Any_Fixed is legal in a real context only if a specific fixed-
3262 -- point type is imposed. If Norman Cohen can be confused by this,
3263 -- it deserves a separate message.
3267 then
3274 -- A user-defined operator is transformed into a function call at
3275 -- this point, so that further processing knows that operators are
3276 -- really operators (i.e. are predefined operators). User-defined
3277 -- operators that are intrinsic are just renamings of the predefined
3278 -- ones, and need not be turned into calls either, but if they rename
3279 -- a different operator, we must transform the node accordingly.
3280 -- Instantiations of Unchecked_Conversion are intrinsic but are
3281 -- treated as functions, even if given an operator designator.
3286 then
3291 and then
3293 N_Subprogram_Renaming_Declaration
3294 then
3297 -- If the node is rewritten, it will be fully resolved in
3298 -- Rewrite_Renamed_Operator.
3307 when N_Aggregate =>
3308 Resolve_Aggregate (N, Ctx_Type);
3310 when N_Allocator =>
3311 Resolve_Allocator (N, Ctx_Type);
3313 when N_Short_Circuit =>
3314 Resolve_Short_Circuit (N, Ctx_Type);
3316 when N_Attribute_Reference =>
3317 Resolve_Attribute (N, Ctx_Type);
3319 when N_Case_Expression =>
3320 Resolve_Case_Expression (N, Ctx_Type);
3322 when N_Character_Literal =>
3323 Resolve_Character_Literal (N, Ctx_Type);
3325 when N_Delta_Aggregate =>
3326 Resolve_Delta_Aggregate (N, Ctx_Type);
3328 when N_Expanded_Name =>
3329 Resolve_Entity_Name (N, Ctx_Type);
3331 when N_Explicit_Dereference =>
3332 Resolve_Explicit_Dereference (N, Ctx_Type);
3334 when N_Expression_With_Actions =>
3335 Resolve_Expression_With_Actions (N, Ctx_Type);
3337 when N_Extension_Aggregate =>
3338 Resolve_Extension_Aggregate (N, Ctx_Type);
3340 when N_Function_Call =>
3341 Resolve_Call (N, Ctx_Type);
3343 when N_Identifier =>
3344 Resolve_Entity_Name (N, Ctx_Type);
3346 when N_If_Expression =>
3347 Resolve_If_Expression (N, Ctx_Type);
3349 when N_Indexed_Component =>
3350 Resolve_Indexed_Component (N, Ctx_Type);
3352 when N_Integer_Literal =>
3353 Resolve_Integer_Literal (N, Ctx_Type);
3355 when N_Membership_Test =>
3356 Resolve_Membership_Op (N, Ctx_Type);
3358 when N_Null =>
3359 Resolve_Null (N, Ctx_Type);
3361 when N_Op_And
3362 | N_Op_Or
3363 | N_Op_Xor
3364 =>
3365 Resolve_Logical_Op (N, Ctx_Type);
3367 when N_Op_Eq
3368 | N_Op_Ne
3369 =>
3370 Resolve_Equality_Op (N, Ctx_Type);
3372 when N_Op_Ge
3373 | N_Op_Gt
3374 | N_Op_Le
3375 | N_Op_Lt
3376 =>
3377 Resolve_Comparison_Op (N, Ctx_Type);
3379 when N_Op_Not =>
3380 Resolve_Op_Not (N, Ctx_Type);
3382 when N_Op_Add
3383 | N_Op_Divide
3384 | N_Op_Mod
3385 | N_Op_Multiply
3386 | N_Op_Rem
3387 | N_Op_Subtract
3388 =>
3389 Resolve_Arithmetic_Op (N, Ctx_Type);
3391 when N_Op_Concat =>
3392 Resolve_Op_Concat (N, Ctx_Type);
3394 when N_Op_Expon =>
3395 Resolve_Op_Expon (N, Ctx_Type);
3397 when N_Op_Abs
3398 | N_Op_Minus
3399 | N_Op_Plus
3400 =>
3401 Resolve_Unary_Op (N, Ctx_Type);
3403 when N_Op_Shift =>
3404 Resolve_Shift (N, Ctx_Type);
3406 when N_Procedure_Call_Statement =>
3407 Resolve_Call (N, Ctx_Type);
3409 when N_Operator_Symbol =>
3410 Resolve_Operator_Symbol (N, Ctx_Type);
3412 when N_Qualified_Expression =>
3413 Resolve_Qualified_Expression (N, Ctx_Type);
3415 -- Why is the following null, needs a comment ???
3417 when N_Quantified_Expression =>
3418 null;
3420 when N_Raise_Expression =>
3421 Resolve_Raise_Expression (N, Ctx_Type);
3423 when N_Raise_xxx_Error =>
3424 Set_Etype (N, Ctx_Type);
3426 when N_Range =>
3427 Resolve_Range (N, Ctx_Type);
3429 when N_Real_Literal =>
3430 Resolve_Real_Literal (N, Ctx_Type);
3432 when N_Reference =>
3433 Resolve_Reference (N, Ctx_Type);
3435 when N_Selected_Component =>
3436 Resolve_Selected_Component (N, Ctx_Type);
3438 when N_Slice =>
3439 Resolve_Slice (N, Ctx_Type);
3441 when N_String_Literal =>
3442 Resolve_String_Literal (N, Ctx_Type);
3444 when N_Interpolated_String_Literal =>
3445 Resolve_Interpolated_String_Literal (N, Ctx_Type);
3447 when N_Target_Name =>
3448 Resolve_Target_Name (N, Ctx_Type);
3450 when N_Type_Conversion =>
3451 Resolve_Type_Conversion (N, Ctx_Type);
3453 when N_Unchecked_Expression =>
3454 Resolve_Unchecked_Expression (N, Ctx_Type);
3456 when N_Unchecked_Type_Conversion =>
3457 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3458 end case;
3460 -- Mark relevant use-type and use-package clauses as effective using
3461 -- the original node because constant folding may have occurred and
3462 -- removed references that need to be examined.
3464 if Nkind (Original_Node (N)) in N_Op then
3465 Mark_Use_Clauses (Original_Node (N));
3466 end if;
3468 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3469 -- expression of an anonymous access type that occurs in the context
3470 -- of a named general access type, except when the expression is that
3471 -- of a membership test. This ensures proper legality checking in
3472 -- terms of allowed conversions (expressions that would be illegal to
3473 -- convert implicitly are allowed in membership tests).
3475 if Ada_Version >= Ada_2012
3476 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3477 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3478 and then Nkind (Parent (N)) not in N_Membership_Test
3479 then
3480 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3481 Analyze_And_Resolve (N, Ctx_Type);
3482 end if;
3484 -- If the subexpression was replaced by a non-subexpression, then
3485 -- all we do is to expand it. The only legitimate case we know of
3486 -- is converting procedure call statement to entry call statements,
3487 -- but there may be others, so we are making this test general.
3489 if Nkind (N) not in N_Subexpr then
3490 Debug_A_Exit ("resolving ", N, " (done)");
3491 Expand (N);
3492 return;
3493 end if;
3495 -- The expression is definitely NOT overloaded at this point, so
3496 -- we reset the Is_Overloaded flag to avoid any confusion when
3497 -- reanalyzing the node.
3499 Set_Is_Overloaded (N, False);
3501 -- Freeze expression type, entity if it is a name, and designated
3502 -- type if it is an allocator (RM 13.14(10,11,13)).
3504 -- Now that the resolution of the type of the node is complete, and
3505 -- we did not detect an error, we can expand this node. We skip the
3506 -- expand call if we are in a default expression, see section
3507 -- "Handling of Default Expressions" in Sem spec.
3509 Debug_A_Exit ("resolving ", N, " (done)");
3511 -- We unconditionally freeze the expression, even if we are in
3512 -- default expression mode (the Freeze_Expression routine tests this
3513 -- flag and only freezes static types if it is set).
3515 -- Ada 2012 (AI05-177): The declaration of an expression function
3516 -- does not cause freezing, but we never reach here in that case.
3517 -- Here we are resolving the corresponding expanded body, so we do
3518 -- need to perform normal freezing.
3520 -- As elsewhere we do not emit freeze node within a generic.
3522 if not Inside_A_Generic then
3523 Freeze_Expression (N);
3524 end if;
3526 -- Now we can do the expansion
3528 Expand (N);
3529 end if;
3530 end Resolve;
3532 -------------
3533 -- Resolve --
3534 -------------
3536 -- Version with check(s) suppressed
3538 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3539 begin
3540 if Suppress = All_Checks then
3541 declare
3542 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3543 begin
3544 Scope_Suppress.Suppress := (others => True);
3545 Resolve (N, Typ);
3546 Scope_Suppress.Suppress := Sva;
3547 end;
3549 else
3550 declare
3551 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3552 begin
3553 Scope_Suppress.Suppress (Suppress) := True;
3554 Resolve (N, Typ);
3555 Scope_Suppress.Suppress (Suppress) := Svg;
3556 end;
3557 end if;
3558 end Resolve;
3560 -------------
3561 -- Resolve --
3562 -------------
3564 -- Version with implicit type
3566 procedure Resolve (N : Node_Id) is
3567 begin
3568 Resolve (N, Etype (N));
3569 end Resolve;
3571 ---------------------
3572 -- Resolve_Actuals --
3573 ---------------------
3575 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3576 Loc : constant Source_Ptr := Sloc (N);
3577 A : Node_Id;
3578 A_Typ : Entity_Id := Empty; -- init to avoid warning
3579 F : Entity_Id;
3580 F_Typ : Entity_Id;
3581 Prev : Node_Id := Empty;
3582 Orig_A : Node_Id;
3583 Real_F : Entity_Id := Empty; -- init to avoid warning
3585 Real_Subp : Entity_Id;
3586 -- If the subprogram being called is an inherited operation for
3587 -- a formal derived type in an instance, Real_Subp is the subprogram
3588 -- that will be called. It may have different formal names than the
3589 -- operation of the formal in the generic, so after actual is resolved
3590 -- the name of the actual in a named association must carry the name
3591 -- of the actual of the subprogram being called.
3593 procedure Check_Aliased_Parameter;
3594 -- Check rules on aliased parameters and related accessibility rules
3595 -- in (RM 3.10.2 (10.2-10.4)).
3597 procedure Check_Argument_Order;
3598 -- Performs a check for the case where the actuals are all simple
3599 -- identifiers that correspond to the formal names, but in the wrong
3600 -- order, which is considered suspicious and cause for a warning.
3602 procedure Check_Prefixed_Call;
3603 -- If the original node is an overloaded call in prefix notation,
3605 -- Try_Object_Operation has already verified that there is a valid
3606 -- interpretation, but the form of the actual can only be determined
3607 -- once the primitive operation is identified.
3610 -- Emit an error concerning the illegal usage of an effectively volatile
3611 -- object for reading in interfering context (SPARK RM 7.1.3(10)).
3614 -- If the actual is missing in a call, insert in the actuals list
3615 -- an instance of the default expression. The insertion is always
3616 -- a named association.
3619 -- Check whether T1 and T2, or their full views, are derived from a
3620 -- common type. Used to enforce the restrictions on array conversions
3621 -- of AI95-00246.
3624 -- Predicate to determine whether an actual that is a concatenation
3625 -- will be evaluated statically and does not need a transient scope.
3626 -- This must be determined before the actual is resolved and expanded
3627 -- because if needed the transient scope must be introduced earlier.
3629 -----------------------------
3630 -- Check_Aliased_Parameter --
3631 -----------------------------
3636 begin
3644 else
3651 -- In a generic body assume the worst for generic formals:
3652 -- they can have a constrained partial view (AI05-041).
3656 and then not Object_Type_Has_Constrained_Partial_View
3658 then
3661 else
3666 else
3678 then
3686 then
3687 Error_Msg_N
3693 --------------------------
3694 -- Check_Argument_Order --
3695 --------------------------
3698 begin
3699 -- Nothing to do if no parameters, or original node is neither a
3700 -- function call nor a procedure call statement (happens in the
3701 -- operator-transformed-to-function call case), or the call is to an
3702 -- operator symbol (which is usually in infix form), or the call does
3703 -- not come from source, or this warning is off.
3705 if not Warn_On_Parameter_Order
3711 N_Defining_Operator_Symbol)
3713 then
3717 declare
3720 begin
3721 -- Nothing to do if only one parameter
3727 -- Here if at least two arguments
3729 declare
3735 -- Set True if an out of order case is found
3737 begin
3738 -- Collect identifier names of actuals, fail if any actual is
3739 -- not a simple identifier, and record max length of name.
3745 else
3751 -- If we got this far, all actuals are identifiers and the list
3752 -- of their names is stored in the Actuals array.
3757 -- If we ran out of formals, that's odd, probably an error
3758 -- which will be detected elsewhere, but abandon the search.
3764 -- If name matches and is in order OK
3769 else
3770 -- If no match, see if it is elsewhere in list and if so
3771 -- flag potential wrong order if type is compatible.
3775 and then
3777 then
3783 -- No match
3791 -- If Formals left over, also probably an error, skip warning
3797 -- Here we give the warning if something was out of order
3800 Error_Msg_N
3807 -------------------------
3808 -- Check_Prefixed_Call --
3809 -------------------------
3818 begin
3819 -- Check whether the call is a prefixed call, with or without
3820 -- additional actuals.
3823 or else
3829 then
3832 then
3833 -- Introduce dereference on object in prefix
3835 New_A :=
3843 then
3844 -- Introduce an implicit 'Access in prefix
3847 Error_Msg_NE
3863 ---------------------------------------
3864 -- Flag_Effectively_Volatile_Objects --
3865 ---------------------------------------
3869 -- Determine whether arbitrary node N denotes an effectively volatile
3870 -- object for reading and if it does, emit an error.
3872 -----------------
3873 -- Flag_Object --
3874 -----------------
3879 begin
3881 -- Do not consider nested function calls because they have
3882 -- already been processed during their own resolution.
3890 -- Identifiers of components and discriminants are not names
3891 -- in the sense of Ada RM 4.1. They can only occur as a
3892 -- selector_name in selected_component or as a choice in
3893 -- component_association.
3899 and then
3903 then
3904 Error_Msg_N
3918 -- Start of processing for Flag_Effectively_Volatile_Objects
3920 begin
3924 --------------------
3925 -- Insert_Default --
3926 --------------------
3932 begin
3933 -- Missing argument in call, nothing to insert
3938 else
3939 -- Note that we do a full New_Copy_Tree, so that any associated
3940 -- Itypes are properly copied. This may not be needed any more,
3941 -- but it does no harm as a safety measure. Defaults of a generic
3942 -- formal may be out of bounds of the corresponding actual (see
3943 -- cc1311b) and an additional check may be required.
3945 Actval :=
3946 New_Copy_Tree
3951 -- Propagate dimension information, if any.
3957 then
3963 then
3966 then
3967 -- If default is a real literal, do not introduce a
3968 -- conversion whose effect may depend on the run-time
3969 -- size of universal real.
3973 else
3984 -- Resolve aggregates with their base type, to avoid scope
3985 -- anomalies: the subtype was first built in the subprogram
3986 -- declaration, and the current call may be nested.
3990 else
3994 else
3997 -- See note above concerning aggregates
4001 then
4004 -- Resolve entities with their own type, which may differ from
4005 -- the type of a reference in a generic context (the view
4006 -- swapping mechanism did not anticipate the re-analysis of
4007 -- default values in calls).
4012 else
4017 -- If default is a tag indeterminate function call, propagate tag
4018 -- to obtain proper dispatching.
4022 then
4027 -- If the default expression raises constraint error, then just
4028 -- silently replace it with an N_Raise_Constraint_Error node, since
4029 -- we already gave the warning on the subprogram spec. If node is
4030 -- already a Raise_Constraint_Error leave as is, to prevent loops in
4031 -- the warnings removal machinery.
4035 then
4044 Assoc :=
4049 -- Case of insertion is first named actual
4053 then
4060 else
4064 else
4068 -- Case of insertion is not first named actual
4070 else
4071 Set_Next_Named_Actual
4083 -------------------
4084 -- Same_Ancestor --
4085 -------------------
4091 begin
4094 then
4100 then
4107 --------------------------
4108 -- Static_Concatenation --
4109 --------------------------
4112 begin
4119 -- Concatenation is static when both operands are static and
4120 -- the concatenation operator is a predefined one.
4123 and then
4125 and then
4130 declare
4132 begin
4135 and then
4139 else
4145 -- Start of processing for Resolve_Actuals
4147 begin
4148 Check_Argument_Order;
4152 and then In_Instance
4155 then
4157 else
4162 Check_Prefixed_Call;
4176 -- If we have an error in any formal or actual, indicated by a type
4177 -- of Any_Type, then abandon resolution attempt, and set result type
4178 -- to Any_Type.
4185 -- For the peculiar case of a user-defined comparison or equality
4186 -- operator that does not return a boolean type, the operands may
4187 -- have been ambiguous for the predefined operator and, therefore,
4188 -- marked with Any_Type. Since the operation has been resolved to
4189 -- the user-defined operator, that is irrelevant, so reset Etype.
4193 then
4196 -- Also skip this if the actual is a Raise_Expression, whose type
4197 -- is imposed from context.
4202 else
4208 -- Case where actual is present
4210 -- If the actual is an entity, generate a reference to it now. We
4211 -- do this before the actual is resolved, because a formal of some
4212 -- protected subprogram, or a task discriminant, will be rewritten
4213 -- during expansion, and the source entity reference may be lost.
4218 then
4219 -- Annotate the tree by creating a variable reference marker when
4220 -- the actual denotes a variable reference, in case the reference
4221 -- is folded or optimized away. The variable reference marker is
4222 -- automatically saved for later examination by the ABE Processing
4223 -- phase. The status of the reference is set as follows:
4225 -- status mode
4226 -- read IN, IN OUT
4227 -- write IN OUT, OUT
4229 if Needs_Variable_Reference_Marker
4232 then
4233 Build_Variable_Reference_Marker
4244 then
4251 -- RM 6.4.1(12): For an out parameter that is passed by
4252 -- copy, the formal parameter object is created, and:
4254 -- * For an access type, the formal parameter is initialized
4255 -- from the value of the actual, without checking that the
4256 -- value satisfies any constraint, any predicate, or any
4257 -- exclusion of the null value.
4259 -- * For a scalar type that has the Default_Value aspect
4260 -- specified, the formal parameter is initialized from the
4261 -- value of the actual, without checking that the value
4262 -- satisfies any constraint or any predicate.
4263 -- I do not understand why this case is included??? this is
4264 -- not a case where an OUT parameter is treated as IN OUT.
4266 -- * For a composite type with discriminants or that has
4267 -- implicit initial values for any subcomponents, the
4268 -- behavior is as for an in out parameter passed by copy.
4270 -- Hence for these cases we generate the read reference now
4271 -- (the write reference will be generated later by
4272 -- Note_Possible_Modification).
4275 and then
4277 or else
4279 and then
4281 or else
4284 or else Is_Partially_Initialized_Type
4286 then
4296 then
4297 -- If style checking mode on, check match of formal name
4305 -- If the formal is Out or In_Out, do not resolve and expand the
4306 -- conversion, because it is subsequently expanded into explicit
4307 -- temporaries and assignments. However, the object of the
4308 -- conversion can be resolved. An exception is the case of tagged
4309 -- type conversion with a class-wide actual. In that case we want
4310 -- the tag check to occur and no temporary will be needed (no
4311 -- representation change can occur) and the parameter is passed by
4312 -- reference, so we go ahead and resolve the type conversion.
4313 -- Another exception is the case of reference to component or
4314 -- subcomponent of a bit-packed array, in which case we want to
4315 -- defer expansion to the point the in and out assignments are
4316 -- performed.
4322 then
4323 declare
4326 begin
4327 -- Check RM 4.6 (24.2/2)
4331 then
4332 -- In a view conversion, the conversion must be legal in
4333 -- both directions, and thus both component types must be
4334 -- aliased, or neither (4.6 (8)).
4336 -- Check RM 4.6 (24.8/2)
4340 then
4341 -- This normally illegal conversion is legal in an
4342 -- expanded instance body because of RM 12.3(11).
4343 -- At runtime, conversion must create a new object.
4346 Error_Msg_N
4351 -- Check RM 4.6 (24/3)
4354 -- Check view conv between unrelated by ref array
4355 -- types.
4359 then
4360 Error_Msg_N
4364 -- In Ada 2005 mode, check view conversion component
4365 -- type cannot be private, tagged, or volatile. Note
4366 -- that we only apply this to source conversions. The
4367 -- generated code can contain conversions which are
4368 -- not subject to this test, and we cannot extract the
4369 -- component type in such cases since it is not
4370 -- present.
4374 then
4375 declare
4378 begin
4383 then
4384 Error_Msg_N
4394 -- AI12-0074 & AI12-0377
4395 -- Check 6.4.1: If the mode is out, the actual parameter is
4396 -- a view conversion, and the type of the formal parameter
4397 -- is a scalar type, then either:
4398 -- - the target and operand type both do not have the
4399 -- Default_Value aspect specified; or
4400 -- - the target and operand type both have the
4401 -- Default_Value aspect specified, and there shall exist
4402 -- a type (other than a root numeric type) that is an
4403 -- ancestor of both the target type and the operand
4404 -- type.
4408 then
4411 then
4412 Error_Msg_N
4417 then
4418 Error_Msg_N
4425 -- Resolve expression if conversion is all OK
4430 then
4434 -- If the actual is a function call that returns a limited
4435 -- unconstrained object that needs finalization, create a
4436 -- transient scope for it, so that it can receive the proper
4437 -- finalization list.
4439 elsif Expander_Active
4445 then
4449 -- A small optimization: if one of the actuals is a concatenation
4450 -- create a block around a procedure call to recover stack space.
4451 -- This alleviates stack usage when several procedure calls in
4452 -- the same statement list use concatenation. We do not perform
4453 -- this wrapping for code statements, where the argument is a
4454 -- static string, and we want to preserve warnings involving
4455 -- sequences of such statements.
4457 elsif Expander_Active
4463 then
4467 else
4471 and then
4474 then
4475 Error_Msg_N
4488 -- (Ada 2005: AI-251): If the actual is an allocator whose
4489 -- directly designated type is a class-wide interface, we build
4490 -- an anonymous access type to use it as the type of the
4491 -- allocator. Later, when the subprogram call is expanded, if
4492 -- the interface has a secondary dispatch table the expander
4493 -- will add a type conversion to force the correct displacement
4494 -- of the pointer.
4497 declare
4501 begin
4502 -- Displace the pointer to the object to reference its
4503 -- secondary dispatch table.
4507 then
4513 -- Ada 2005, AI-162:If the actual is an allocator, the
4514 -- innermost enclosing statement is the master of the
4515 -- created object. This needs to be done with expansion
4516 -- enabled only, otherwise the transient scope will not
4517 -- be removed in the expansion of the wrapped construct.
4519 if Expander_Active
4522 then
4523 Establish_Transient_Scope
4533 -- (Ada 2005): The call may be to a primitive operation of a
4534 -- tagged synchronized type, declared outside of the type. In
4535 -- this case the controlling actual must be converted to its
4536 -- corresponding record type, which is the formal type. The
4537 -- actual may be a subtype, either because of a constraint or
4538 -- because it is a generic actual, so use base type to locate
4539 -- concurrent type.
4546 then
4547 -- If the actual is overloaded, look for an interpretation
4548 -- that has a synchronized type.
4553 else
4554 declare
4558 begin
4563 then
4573 declare
4576 begin
4579 else
4583 -- Tagged synchronized type (case 1): the actual is a
4584 -- concurrent type.
4588 then
4590 Unchecked_Convert_To
4594 -- Tagged synchronized type (case 2): the formal is a
4595 -- concurrent type.
4598 and then Present
4603 then
4606 -- Common case
4608 else
4613 -- Not a synchronized operation
4615 else
4623 -- An actual cannot be an untagged formal incomplete type
4628 then
4629 Error_Msg_N
4633 -- For mode IN, if actual is an entity, and the type of the formal
4634 -- has warnings suppressed, then we reset Never_Set_In_Source for
4635 -- the calling entity. The reason for this is to catch cases like
4636 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4637 -- uses trickery to modify an IN parameter.
4644 then
4648 -- Perform error checks for IN and IN OUT parameters
4652 -- Check unset reference. For scalar parameters, it is clearly
4653 -- wrong to pass an uninitialized value as either an IN or
4654 -- IN-OUT parameter. For composites, it is also clearly an
4655 -- error to pass a completely uninitialized value as an IN
4656 -- parameter, but the case of IN OUT is trickier. We prefer
4657 -- not to give a warning here. For example, suppose there is
4658 -- a routine that sets some component of a record to False.
4659 -- It is perfectly reasonable to make this IN-OUT and allow
4660 -- either initialized or uninitialized records to be passed
4661 -- in this case.
4663 -- For partially initialized composite values, we also avoid
4664 -- warnings, since it is quite likely that we are passing a
4665 -- partially initialized value and only the initialized fields
4666 -- will in fact be read in the subprogram.
4671 then
4675 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4676 -- actual to a nested call, since this constitutes a reading of
4677 -- the parameter, which is not allowed.
4682 then
4687 -- In -gnatd.q mode, forget that a given array is constant when
4688 -- it is passed as an IN parameter to a foreign-convention
4689 -- subprogram. This is in case the subprogram evilly modifies the
4690 -- object. Of course, correct code would use IN OUT.
4692 if Debug_Flag_Dot_Q
4698 then
4702 -- Case of OUT or IN OUT parameter
4706 -- For an Out parameter, check for useless assignment. Note
4707 -- that we can't set Last_Assignment this early, because we may
4708 -- kill current values in Resolve_Call, and that call would
4709 -- clobber the Last_Assignment field.
4711 -- Note: call Warn_On_Useless_Assignment before doing the check
4712 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4713 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4714 -- reflects the last assignment, not this one.
4721 then
4726 -- Validate the form of the actual. Note that the call to
4727 -- Is_OK_Variable_For_Out_Formal generates the required
4728 -- reference in this case.
4730 -- A call to an initialization procedure for an aggregate
4731 -- component may initialize a nested component of a constant
4732 -- designated object. In this context the object is variable.
4736 then
4742 then
4743 Error_Msg_N
4748 Error_Msg_N
4755 -- What's the following about???
4759 else
4760 Kill_All_Checks;
4769 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4773 -- Apply predicate tests except in certain special cases. Note
4774 -- that it might be more consistent to apply these only when
4775 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4776 -- for the outbound predicate tests ??? In any case indicate
4777 -- the function being called, for better warnings if the call
4778 -- leads to an infinite recursion.
4784 -- Apply required constraint checks
4797 then
4800 -- For view conversions of a discriminated object, apply
4801 -- check to object itself, the conversion alreay has the
4802 -- proper type.
4806 then
4813 then
4819 then
4822 else
4826 -- Ada 2005 (AI-231): Note that the controlling parameter case
4827 -- already existed in Ada 95, which is partially checked
4828 -- elsewhere (see Checks), and we don't want the warning
4829 -- message to differ.
4834 then
4836 Apply_Compile_Time_Constraint_Error
4842 Apply_Compile_Time_Constraint_Error
4851 -- Checks for OUT parameters and IN OUT parameters
4855 -- If there is a type conversion, make sure the return value
4856 -- meets the constraints of the variable before the conversion.
4861 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4862 -- which would prevent the check from being generated.
4863 -- This is for Starlet only though, so long obsolete.
4868 then
4870 else
4871 Apply_Scalar_Range_Check
4875 -- In addition the return value must meet the constraints
4876 -- of the object type (see the comment below).
4880 else
4881 Apply_Range_Check
4885 -- If no conversion, apply scalar range checks and length check
4886 -- based on the subtype of the actual (NOT that of the formal).
4887 -- This indicates that the check takes place on return from the
4888 -- call. During expansion the required constraint checks are
4889 -- inserted. In GNATprove mode, in the absence of expansion,
4890 -- the flag indicates that the returned value is valid.
4892 else
4898 then
4901 else
4906 -- Note: we do not apply the predicate checks for the case of
4907 -- OUT and IN OUT parameters. They are instead applied in the
4908 -- Expand_Actuals routine in Exp_Ch6.
4911 -- If the formal is of an unconstrained array subtype with fixed
4912 -- lower bound, then sliding to that bound may be needed.
4918 -- An actual associated with an access parameter is implicitly
4919 -- converted to the anonymous access type of the formal and must
4920 -- satisfy the legality checks for access conversions.
4924 Error_Msg_N
4928 -- If the actual is an access selected component of a variable,
4929 -- the call may modify its designated object. It is reasonable
4930 -- to treat this as a potential modification of the enclosing
4931 -- record, to prevent spurious warnings that it should be
4932 -- declared as a constant, because intuitively programmers
4933 -- regard the designated subcomponent as part of the record.
4938 then
4943 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
4947 then
4950 then
4951 Error_Msg_NE
4954 Error_Msg_N
4959 then
4960 Error_Msg_NE
4963 Error_Msg_N
4968 then
4969 Error_Msg_NE
4972 Error_Msg_N
4976 -- Check for nonatomic subcomponent of a full access object
4977 -- in Ada 2022 (RM C.6 (12)).
4982 then
4983 Error_Msg_N
4986 Error_Msg_NE
4992 -- Check that subprograms don't have improper controlling
4993 -- arguments (RM 3.9.2 (9)).
4995 -- A primitive operation may have an access parameter of an
4996 -- incomplete tagged type, but a dispatching call is illegal
4997 -- if the type is still incomplete.
5003 declare
5005 begin
5009 then
5010 Error_Msg_NE
5021 -- Apply legality rule 3.9.2 (9/1)
5023 -- Skip this check on helpers and indirect-call wrappers built to
5024 -- support class-wide preconditions.
5029 and then not In_Instance
5032 then
5037 Error_Msg_NE
5041 -- Apply the checks described in 3.10.2(27): if the context is a
5042 -- specific access-to-object, the actual cannot be class-wide.
5043 -- Use base type to exclude access_to_subprogram cases.
5050 and then
5055 -- Disable these checks for call to imported C++ subprograms
5057 and then not
5061 then
5062 Error_Msg_N
5067 Error_Msg_NE
5072 Check_Aliased_Parameter;
5076 -- If it is a named association, treat the selector_name as a
5077 -- proper identifier, and mark the corresponding entity.
5081 -- Ignore reference in SPARK mode, as it refers to an entity not
5082 -- in scope at the point of reference, so the reference should
5083 -- be ignored for computing effects of subprograms.
5085 and then not GNATprove_Mode
5086 then
5087 -- If subprogram is overridden, use name of formal that
5088 -- is being called.
5094 else
5108 -- The following checks are only relevant when SPARK_Mode is on as
5109 -- they are not standard Ada legality rule. Internally generated
5110 -- temporaries are ignored.
5114 -- Inspect the expression and flag each effectively volatile
5115 -- object for reading as illegal because it appears within
5116 -- an interfering context. Note that this is usually done
5117 -- in Resolve_Entity_Name, but when the effectively volatile
5118 -- object for reading appears as an actual in a call, the call
5119 -- must be resolved first.
5124 -- A formal parameter of a specific tagged type whose related
5125 -- subprogram is subject to pragma Extensions_Visible with value
5126 -- "False" cannot act as an actual in a subprogram with value
5127 -- "True" (SPARK RM 6.1.7(3)).
5129 -- No check needed for helpers and indirect-call wrappers built to
5130 -- support class-wide preconditions.
5134 Extensions_Visible_True
5136 then
5137 Error_Msg_N
5140 Error_Msg_NE
5144 -- The actual parameter of a Ghost subprogram whose formal is of
5145 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5153 then
5154 Error_Msg_NE
5160 else
5165 -- (AI12-0397): The target of a subprogram call that occurs within
5166 -- the expression of an Default_Initial_Condition aspect and has
5167 -- an actual that is the current instance of the type must be
5168 -- either a primitive of the type or a class-wide subprogram,
5169 -- because the type of the current instance in such an aspect is
5170 -- considered to be a notional formal derived type whose only
5171 -- operations correspond to the primitives of the enclosing type.
5172 -- Nonprimitives can be called, but the current instance must be
5173 -- converted rather than passed directly. Note that a current
5174 -- instance of a type with DIC will occur as a reference to an
5175 -- in-mode formal of an enclosing DIC procedure or partial DIC
5176 -- procedure. (It seems that this check should perhaps also apply
5177 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5178 -- aspects???)
5186 -- We check Comes_From_Source to exclude inherited primitives
5187 -- from being flagged, because such subprograms turn out to not
5188 -- always have the Is_Primitive flag set. ???
5194 then
5195 Error_Msg_NE
5202 -- Case where actual is not present
5204 else
5205 Insert_Default;
5216 -----------------------
5217 -- Resolve_Allocator --
5218 -----------------------
5230 procedure Check_Allocator_Discrim_Accessibility
5233 -- Check that accessibility level associated with an access discriminant
5234 -- initialized in an allocator by the expression Disc_Exp is not deeper
5235 -- than the level of the allocator type Alloc_Typ. An error message is
5236 -- issued if this condition is violated. Specialized checks are done for
5237 -- the cases of a constraint expression which is an access attribute or
5238 -- an access discriminant.
5240 procedure Check_Allocator_Discrim_Accessibility_Exprs
5243 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5244 -- across all expressions within a given conditional expression.
5247 -- If the allocator is an actual in a call, it is allowed to be class-
5248 -- wide when the context is not because it is a controlling actual.
5250 -------------------------------------------
5251 -- Check_Allocator_Discrim_Accessibility --
5252 -------------------------------------------
5254 procedure Check_Allocator_Discrim_Accessibility
5257 is
5258 begin
5261 then
5262 Error_Msg_N
5265 -- When the expression is an Access attribute the level of the prefix
5266 -- object must not be deeper than that of the allocator's type.
5270 Attribute_Access
5271 and then Static_Accessibility_Level
5274 then
5275 Error_Msg_N
5277 Disc_Exp);
5279 -- When the expression is an access discriminant the check is against
5280 -- the level of the prefix object.
5284 and then Static_Accessibility_Level
5287 then
5288 Error_Msg_N
5290 Disc_Exp);
5292 -- All other cases are legal
5294 else
5299 -------------------------------------------------
5300 -- Check_Allocator_Discrim_Accessibility_Exprs --
5301 -------------------------------------------------
5303 procedure Check_Allocator_Discrim_Accessibility_Exprs
5306 is
5310 begin
5311 -- When conditional expressions are constant folded we know at
5312 -- compile time which expression to check - so don't bother with
5313 -- the rest of the cases.
5318 -- Non-constant-folded if expressions
5321 -- Check both expressions if they are still present in the face
5322 -- of expansion.
5329 Check_Allocator_Discrim_Accessibility_Exprs
5334 -- Non-constant-folded case expressions
5337 -- Check all alternatives
5341 Check_Allocator_Discrim_Accessibility_Exprs
5347 -- Base case, check the accessibility of the original node of the
5348 -- expression.
5350 else
5355 ----------------------------
5356 -- In_Dispatching_Context --
5357 ----------------------------
5362 begin
5368 -- Start of processing for Resolve_Allocator
5370 begin
5371 -- Replace general access with specific type
5381 -- For qualified expression, resolve the expression using the given
5382 -- subtype (nothing to do for type mark, subtype indication)
5387 and then not In_Dispatching_Context
5388 then
5389 Error_Msg_N
5393 -- Do a full resolution to apply constraint and predicate checks
5398 -- Allocators generated by the build-in-place expansion mechanism
5399 -- are explicitly marked as coming from source but do not need to be
5400 -- checked for limited initialization. To exclude this case, ensure
5401 -- that the parent of the allocator is a source node.
5402 -- The return statement constructed for an Expression_Function does
5403 -- not come from source but requires a limited check.
5407 and then
5409 or else
5413 and then not In_Instance_Body
5414 then
5417 Error_Msg_N
5420 else
5421 Error_Msg_N
5429 -- Calls to build-in-place functions are not currently supported in
5430 -- allocators for access types associated with a simple storage pool.
5431 -- Supporting such allocators may require passing additional implicit
5432 -- parameters to build-in-place functions (or a significant revision
5433 -- of the current b-i-p implementation to unify the handling for
5434 -- multiple kinds of storage pools). ???
5438 then
5439 declare
5442 begin
5444 and then
5445 Present (Get_Rep_Pragma
5447 then
5448 Error_Msg_N
5455 -- A special accessibility check is needed for allocators that
5456 -- constrain access discriminants. The level of the type of the
5457 -- expression used to constrain an access discriminant cannot be
5458 -- deeper than the type of the allocator (in contrast to access
5459 -- parameters, where the level of the actual can be arbitrary).
5461 -- We can't use Valid_Conversion to perform this check because in
5462 -- general the type of the allocator is unrelated to the type of
5463 -- the access discriminant.
5467 then
5474 then
5477 -- Get the first component expression of the aggregate
5487 else
5491 else
5497 Check_Allocator_Discrim_Accessibility_Exprs
5511 else
5516 else
5525 -- For a subtype mark or subtype indication, freeze the subtype
5527 else
5531 Error_Msg_N
5535 -- A special accessibility check is needed for allocators that
5536 -- constrain access discriminants. The level of the type of the
5537 -- expression used to constrain an access discriminant cannot be
5538 -- deeper than the type of the allocator (in contrast to access
5539 -- parameters, where the level of the actual can be arbitrary).
5540 -- We can't use Valid_Conversion to perform this check because
5541 -- in general the type of the allocator is unrelated to the type
5542 -- of the access discriminant.
5547 then
5557 else
5561 Check_Allocator_Discrim_Accessibility_Exprs
5572 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5573 -- check that the level of the type of the created object is not deeper
5574 -- than the level of the allocator's access type, since extensions can
5575 -- now occur at deeper levels than their ancestor types. This is a
5576 -- static accessibility level check; a run-time check is also needed in
5577 -- the case of an initialized allocator with a class-wide argument (see
5578 -- Expand_Allocator_Expression).
5582 then
5583 declare
5586 begin
5591 else
5597 then
5600 Error_Msg_N
5610 -- Do not apply Ada 2005 accessibility checks on a class-wide
5611 -- allocator if the type given in the allocator is a formal
5612 -- type or within a formal package. A run-time check will be
5613 -- performed in the instance.
5617 then
5618 Error_Msg_N
5626 -- Check for allocation from an empty storage pool. But do not complain
5627 -- if it's a return statement for a build-in-place function, because the
5628 -- allocator is there just in case the caller uses an allocator. If the
5629 -- caller does use an allocator, it will be caught at the call site.
5633 then
5636 -- If the context is an unchecked conversion, as may happen within an
5637 -- inlined subprogram, the allocator is being resolved with its own
5638 -- anonymous type. In that case, if the target type has a specific
5639 -- storage pool, it must be inherited explicitly by the allocator type.
5643 then
5644 Set_Associated_Storage_Pool
5652 -- Check that an allocator with task parts isn't for a nested access
5653 -- type when restriction No_Task_Hierarchy applies.
5657 then
5661 -- An illegal allocator may be rewritten as a raise Program_Error
5662 -- statement.
5666 -- Avoid coextension processing for an allocator that is the
5667 -- expansion of a build-in-place function call.
5671 N_Qualified_Expression
5673 N_Function_Call
5674 and then Is_Expanded_Build_In_Place_Call
5676 then
5679 else
5680 -- An anonymous access discriminant is the definition of a
5681 -- coextension.
5685 N_Discriminant_Specification
5686 then
5687 declare
5691 begin
5694 -- Ada 2012 AI05-0052: If the designated type of the
5695 -- allocator is limited, then the allocator shall not
5696 -- be used to define the value of an access discriminant
5697 -- unless the discriminated type is immutably limited.
5702 then
5703 Error_Msg_N
5706 N);
5710 -- Avoid marking an allocator as a dynamic coextension if it is
5711 -- within a static construct.
5716 -- Finalization and deallocation of coextensions utilizes an
5717 -- approximate implementation which does not directly adhere
5718 -- to the semantic rules. Warn on potential issues involving
5719 -- coextensions.
5722 Error_Msg_N
5725 else
5726 Error_Msg_N
5732 -- Cleanup for potential static coextensions
5734 else
5738 -- Anonymous access-to-controlled objects are not finalized on
5739 -- time because this involves run-time ownership and currently
5740 -- this property is not available. In rare cases the object may
5741 -- not be finalized at all. Warn on potential issues involving
5742 -- anonymous access-to-controlled objects.
5746 then
5747 Error_Msg_N
5757 -- Report a simple error: if the designated object is a local task,
5758 -- its body has not been seen yet, and its activation will fail an
5759 -- elaboration check.
5766 then
5772 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5773 -- type with a task component on a subpool. This action must raise
5774 -- Program_Error at runtime.
5780 then
5792 ---------------------------
5793 -- Resolve_Arithmetic_Op --
5794 ---------------------------
5796 -- Used for resolving all arithmetic operators except exponentiation
5807 -- We do the resolution using the base type, because intermediate values
5808 -- in expressions always are of the base type, not a subtype of it.
5811 -- Returns True if N is in a context that expects "any real type"
5814 -- Return True iff given type is Integer or universal real/integer
5817 -- Choose type of integer literal in fixed-point operation to conform
5818 -- to available fixed-point type. T is the type of the other operand,
5819 -- which is needed to determine the expected type of N.
5822 -- Set operand type to T if universal
5824 -------------------------------
5825 -- Expected_Type_Is_Any_Real --
5826 -------------------------------
5829 begin
5830 -- N is the expression after "delta" in a fixed_point_definition;
5831 -- see RM-3.5.9(6):
5834 | N_Decimal_Fixed_Point_Definition
5836 -- N is one of the bounds in a real_range_specification;
5837 -- see RM-3.5.7(5):
5839 | N_Real_Range_Specification
5841 -- N is the expression of a delta_constraint;
5842 -- see RM-J.3(3):
5844 | N_Delta_Constraint;
5847 -----------------------------
5848 -- Is_Integer_Or_Universal --
5849 -----------------------------
5856 begin
5861 else
5866 then
5877 ----------------------------
5878 -- Set_Mixed_Mode_Operand --
5879 ----------------------------
5885 begin
5888 -- A universal integer literal is resolved as standard integer
5889 -- except in the case of a fixed-point result, where we leave it
5890 -- as universal (to be handled by Exp_Fixd later on)
5894 else
5901 then
5902 -- A universal real can appear in a fixed-type context. We resolve
5903 -- the literal with that context, even though this might raise an
5904 -- exception prematurely (the other operand may be zero).
5911 then
5912 -- Integer arg in mixed-mode operation. Resolve with universal
5913 -- type, in case preference rule must be applied.
5919 -- If the operand is part of a fixed multiplication operation,
5920 -- a conversion will be applied to each operand, so resolve it
5921 -- with its own type.
5926 else
5927 -- Not a mixed-mode operation, resolve with context
5934 -- N may itself be a mixed-mode operation, so use context type
5941 then
5942 -- Must be (fixed * fixed) operation, operand must have one
5943 -- compatible interpretation.
5950 then
5951 -- C * F(X) in a fixed context, where C is a real literal or a
5952 -- fixed-point expression. F must have either a fixed type
5953 -- interpretation or an integer interpretation, but not both.
5960 else
5967 else
5975 -- Reanalyze the literal with the fixed type of the context. If
5976 -- context is Universal_Fixed, we are within a conversion, leave
5977 -- the literal as a universal real because there is no usable
5978 -- fixed type, and the target of the conversion plays no role in
5979 -- the resolution.
5981 declare
5985 begin
5988 else
5994 then
5996 else
6004 -- A universal real conditional expression can appear in a fixed-type
6005 -- context and must be resolved with that context to facilitate the
6006 -- code generation in the back end. However, If the context is
6007 -- Universal_fixed (i.e. as an operand of a multiplication/division
6008 -- involving a fixed-point operand) the conditional expression must
6009 -- resolve to a unique visible fixed_point type, normally Duration.
6014 then
6018 else
6022 else
6027 ----------------------
6028 -- Set_Operand_Type --
6029 ----------------------
6032 begin
6038 -- Start of processing for Resolve_Arithmetic_Op
6040 begin
6045 then
6049 -- Special-case for mixed-mode universal expressions or fixed point type
6050 -- operation: each argument is resolved separately. The same treatment
6051 -- is required if one of the operands of a fixed point operation is
6052 -- universal real, since in this case we don't do a conversion to a
6053 -- specific fixed-point type (instead the expander handles the case).
6055 -- Set the type of the node to its universal interpretation because
6056 -- legality checks on an exponentiation operand need the context.
6061 then
6072 or else
6075 then
6080 -- If context is a fixed type and one operand is integer, the other
6081 -- is resolved with the type of the context.
6086 then
6093 then
6097 -- If both operands are universal and the context is a floating
6098 -- point type, the operands are resolved to the type of the context.
6104 else
6109 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6110 -- multiplying operators from being used when the expected type is
6111 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6112 -- some cases where the expected type is actually Any_Real;
6113 -- Expected_Type_Is_Any_Real takes care of that case.
6117 then
6121 N_Type_Conversion | N_Unchecked_Type_Conversion
6122 then
6129 else
6133 N_Type_Conversion | N_Unchecked_Type_Conversion
6134 then
6135 Error_Msg_N
6140 -- The expected type is "any real type" in contexts like
6142 -- type T is delta <universal_fixed-expression> ...
6144 -- in which case we need to set the type to Universal_Real
6145 -- so that static expression evaluation will work properly.
6149 else
6159 then
6164 -- If no previous errors, this is only possible if one operand is
6165 -- overloaded and the context is universal. Resolve as such.
6170 else
6172 and then
6174 then
6178 -- If the context is Universal_Fixed and the operands are also
6179 -- universal fixed, this is an error, unless there is only one
6180 -- applicable fixed_point type (usually Duration).
6188 else
6193 else
6198 -- If one of the arguments was resolved to a non-universal type.
6199 -- label the result of the operation itself with the same type.
6200 -- Do the same for the universal argument, if any.
6212 -- Set overflow and division checking bit
6219 -- Give warning if explicit division by zero
6223 then
6229 or else
6232 then
6233 -- Specialize the warning message according to the operation.
6234 -- When SPARK_Mode is On, force a warning instead of an error
6235 -- in that case, as this likely corresponds to deactivated
6236 -- code. The following warnings are for the case
6241 -- For division, we have two cases, for float division
6242 -- of an unconstrained float type, on a machine where
6243 -- Machine_Overflows is false, we don't get an exception
6244 -- at run-time, but rather an infinity or Nan. The Nan
6245 -- case is pretty obscure, so just warn about infinities.
6249 and then not Machine_Overflows_On_Target
6250 then
6251 Error_Msg_N
6255 -- For all other cases, we get a Constraint_Error
6257 else
6258 Apply_Compile_Time_Constraint_Error
6265 Apply_Compile_Time_Constraint_Error
6271 Apply_Compile_Time_Constraint_Error
6276 -- Division by zero can only happen with division, rem,
6277 -- and mod operations.
6283 -- Otherwise just set the flag to check at run time
6285 else
6290 -- If Restriction No_Implicit_Conditionals is active, then it is
6291 -- violated if either operand can be negative for mod, or for rem
6292 -- if both operands can be negative.
6296 then
6297 declare
6304 -- Set if corresponding operand might be negative
6306 begin
6307 Determine_Range
6311 Determine_Range
6315 -- Check if we will be generating conditionals. There are two
6316 -- cases where that can happen, first for REM, the only case
6317 -- is largest negative integer mod -1, where the division can
6318 -- overflow, but we still have to give the right result. The
6319 -- front end generates a test for this annoying case. Here we
6320 -- just test if both operands can be negative (that's what the
6321 -- expander does, so we match its logic here).
6323 -- The second case is mod where either operand can be negative.
6324 -- In this case, the back end has to generate additional tests.
6327 or else
6329 then
6340 ------------------
6341 -- Resolve_Call --
6342 ------------------
6357 begin
6358 -- Preserve relevant elaboration-related attributes of the context which
6359 -- are no longer available or very expensive to recompute once analysis,
6360 -- resolution, and expansion are over.
6362 Mark_Elaboration_Attributes
6368 -- The context imposes a unique interpretation with type Typ on a
6369 -- procedure or function call. Find the entity of the subprogram that
6370 -- yields the expected type, and propagate the corresponding formal
6371 -- constraints on the actuals. The caller has established that an
6372 -- interpretation exists, and emitted an error if not unique.
6374 -- First deal with the case of a call to an access-to-subprogram,
6375 -- dereference made explicit in Analyze_Call.
6381 else
6382 -- Find the interpretation whose type (a subprogram type) has a
6383 -- return type that is compatible with the context. Analysis of
6384 -- the node has established that one exists.
6403 -- If the prefix is not an entity, then resolve it
6409 -- For an indirect call, we always invalidate checks, since we do not
6410 -- know whether the subprogram is local or global. Yes we could do
6411 -- better here, e.g. by knowing that there are no local subprograms,
6412 -- but it does not seem worth the effort. Similarly, we kill all
6413 -- knowledge of current constant values.
6415 Kill_Current_Values;
6417 -- If this is a procedure call which is really an entry call, do
6418 -- the conversion of the procedure call to an entry call. Protected
6419 -- operations use the same circuitry because the name in the call
6420 -- can be an arbitrary expression with special resolution rules.
6424 then
6431 -- Annotate the tree by creating a call marker in case the original
6432 -- call is transformed by expansion. The call marker is automatically
6433 -- saved for later examination by the ABE Processing phase.
6437 -- Kill checks and constant values, as above for indirect case
6438 -- Who knows what happens when another task is activated?
6440 Kill_Current_Values;
6443 -- Normal subprogram call with name established in Resolve
6449 -- Otherwise we must have the case of an overloaded call
6451 else
6454 -- Initialize Nam to prevent warning (we know it will be assigned
6455 -- in the loop below, but the compiler does not know that).
6471 -- Check that a call to Current_Task does not occur in an entry body
6474 declare
6477 begin
6479 loop
6482 -- Exclude calls that occur within the default of a formal
6483 -- parameter of the entry, since those are evaluated outside
6484 -- of the body.
6491 then
6494 Error_Msg_NE
6508 -- Check that a procedure call does not occur in the context of the
6509 -- entry call statement of a conditional or timed entry call. Note that
6510 -- the case of a call to a subprogram renaming of an entry will also be
6511 -- rejected. The test for N not being an N_Entry_Call_Statement is
6512 -- defensive, covering the possibility that the processing of entry
6513 -- calls might reach this point due to later modifications of the code
6514 -- above.
6519 then
6523 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6524 -- for a procedure_or_entry_call, the procedure_name or
6525 -- procedure_prefix of the procedure_call_statement shall denote
6526 -- an entry renamed by a procedure, or (a view of) a primitive
6527 -- subprogram of a limited interface whose first parameter is
6528 -- a controlling parameter.
6533 then
6534 Error_Msg_N
6539 -- Check that this is not a call to a protected procedure or entry from
6540 -- within a protected function.
6544 -- Freeze the subprogram name if not in a spec-expression. Note that
6545 -- we freeze procedure calls as well as function calls. Procedure calls
6546 -- are not frozen according to the rules (RM 13.14(14)) because it is
6547 -- impossible to have a procedure call to a non-frozen procedure in
6548 -- pure Ada, but in the code that we generate in the expander, this
6549 -- rule needs extending because we can generate procedure calls that
6550 -- need freezing.
6552 -- In Ada 2012, expression functions may be called within pre/post
6553 -- conditions of subsequent functions or expression functions. Such
6554 -- calls do not freeze when they appear within generated bodies,
6555 -- (including the body of another expression function) which would
6556 -- place the freeze node in the wrong scope. An expression function
6557 -- is frozen in the usual fashion, by the appearance of a real body,
6558 -- or at the end of a declarative part. However an implicit call to
6559 -- an expression function may appear when it is part of a default
6560 -- expression in a call to an initialization procedure, and must be
6561 -- frozen now, even if the body is inserted at a later point.
6562 -- Otherwise, the call freezes the expression if expander is active,
6563 -- for example as part of an object declaration.
6566 and then not In_Spec_Expression
6568 and then
6571 then
6574 -- Force freeze of expression function in call
6583 -- For a predefined operator, the type of the result is the type imposed
6584 -- by context, except for a predefined operation on universal fixed.
6585 -- Otherwise the type of the call is the type returned by the subprogram
6586 -- being called.
6593 -- If the subprogram returns an array type, and the context requires the
6594 -- component type of that array type, the node is really an indexing of
6595 -- the parameterless call. Resolve as such. A pathological case occurs
6596 -- when the type of the component is an access to the array type. In
6597 -- this case the call is truly ambiguous. If the call is to an intrinsic
6598 -- subprogram, it can't be an indexed component. This check is necessary
6599 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6600 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6601 -- pointers to the same array), the compiler gets confused and does an
6602 -- infinite recursion.
6605 and then
6608 or else
6611 and then
6614 then
6615 declare
6620 begin
6621 -- If this is a parameterless call there is no ambiguity and the
6622 -- call has the type of the function.
6631 -- Annotate the tree by creating a call marker in case the
6632 -- original call is transformed by expansion. The call marker
6633 -- is automatically saved for later examination by the ABE
6634 -- Processing phase.
6641 then
6642 Error_Msg_N
6644 else
6647 -- The called entity may be an explicit dereference, in which
6648 -- case there is no entity to set.
6656 or else
6658 and then
6660 then
6663 -- Indexed call to a parameterless function
6665 Index_Node :=
6667 Prefix =>
6670 else
6671 -- An Ada 2005 prefixed call to a primitive operation
6672 -- whose first parameter is the prefix. This prefix was
6673 -- prepended to the parameter list, which is actually a
6674 -- list of indexes. Remove the prefix in order to build
6675 -- the proper indexed component.
6677 Index_Node :=
6679 Prefix =>
6682 Parameter_Associations =>
6683 New_List
6688 -- Preserve the parenthesis count of the node
6692 -- Since we are correcting a node classification error made
6693 -- by the parser, we call Replace rather than Rewrite.
6704 -- Annotate the tree by creating a call marker in case
6705 -- the original call is transformed by expansion. The call
6706 -- marker is automatically saved for later examination by
6707 -- the ABE Processing phase.
6718 else
6719 -- If the called function is not declared in the main unit and it
6720 -- returns the limited view of type then use the available view (as
6721 -- is done in Try_Object_Operation) to prevent back-end confusion;
6722 -- for the function entity itself. The call must appear in a context
6723 -- where the nonlimited view is available. If the function entity is
6724 -- in the extended main unit then no action is needed, because the
6725 -- back end handles this case. In either case the type of the call
6726 -- is the nonlimited view.
6730 then
6737 else
6742 -- In the case where the call is to an overloaded subprogram, Analyze
6743 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6744 -- such a case Normalize_Actuals needs to be called once more to order
6745 -- the actuals correctly. Otherwise the call will have the ordering
6746 -- given by the last overloaded subprogram whether this is the correct
6747 -- one being called or not.
6754 -- In any case, call is fully resolved now. Reset Overload flag, to
6755 -- prevent subsequent overload resolution if node is analyzed again
6760 -- A Ghost entity must appear in a specific context
6766 -- If we are calling the current subprogram from immediately within its
6767 -- body, then that is the case where we can sometimes detect cases of
6768 -- infinite recursion statically. Do not try this in case restriction
6769 -- No_Recursion is in effect anyway, and do it only for source calls.
6774 -- Issue warning for possible infinite recursion in the absence
6775 -- of the No_Recursion restriction.
6781 then
6782 -- Here we detected and flagged an infinite recursion, so we do
6783 -- not need to test the case below for further warnings. Also we
6784 -- are all done if we now have a raise SE node.
6790 -- If call is to immediately containing subprogram, then check for
6791 -- the case of a possible run-time detectable infinite recursion.
6793 else
6797 -- Ada 2022 (AI12-0075): Static functions are never allowed
6798 -- to make a recursive call, as specified by 6.8(5.4/5).
6801 Error_Msg_N
6810 -- Although in general case, recursion is not statically
6811 -- checkable, the case of calling an immediately containing
6812 -- subprogram is easy to catch.
6818 -- If the recursive call is to a parameterless subprogram,
6819 -- then even if we can't statically detect infinite
6820 -- recursion, this is pretty suspicious, and we output a
6821 -- warning. Furthermore, we will try later to detect some
6822 -- cases here at run time by expanding checking code (see
6823 -- Detect_Infinite_Recursion in package Exp_Ch6).
6825 -- If the recursive call is within a handler, do not emit a
6826 -- warning, because this is a common idiom: loop until input
6827 -- is correct, catch illegal input in handler and restart.
6833 then
6834 -- For the case of a procedure call. We give the message
6835 -- only if the call is the first statement in a sequence
6836 -- of statements, or if all previous statements are
6837 -- simple assignments. This is simply a heuristic to
6838 -- decrease false positives, without losing too many good
6839 -- warnings. The idea is that these previous statements
6840 -- may affect global variables the procedure depends on.
6841 -- We also exclude raise statements, that may arise from
6842 -- constraint checks and are probably unrelated to the
6843 -- intended control flow.
6847 then
6848 declare
6850 begin
6854 | N_Raise_Constraint_Error
6855 then
6864 -- Do not give warning if we are in a conditional context
6866 declare
6868 begin
6874 then
6879 -- Here warning is to be issued
6895 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6899 -- If subprogram name is a predefined operator, it was given in
6900 -- functional notation. Replace call node with operator node, so
6901 -- that actuals can be resolved appropriately.
6913 -- Create a transient scope if the resulting type requires it
6915 -- There are several notable exceptions:
6917 -- a) In init procs, the transient scope overhead is not needed, and is
6918 -- even incorrect when the call is a nested initialization call for a
6919 -- component whose expansion may generate adjust calls. However, if the
6920 -- call is some other procedure call within an initialization procedure
6921 -- (for example a call to Create_Task in the init_proc of the task
6922 -- run-time record) a transient scope must be created around this call.
6924 -- b) Enumeration literal pseudo-calls need no transient scope
6926 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6927 -- functions) do not use the secondary stack even though the return
6928 -- type may be unconstrained.
6930 -- d) Calls to a build-in-place function, since such functions may
6931 -- allocate their result directly in a target object, and cases where
6932 -- the result does get allocated in the secondary stack are checked for
6933 -- within the specialized Exp_Ch6 procedures for expanding those
6934 -- build-in-place calls.
6936 -- e) Calls to inlinable expression functions do not use the secondary
6937 -- stack (since the call will be replaced by its returned object).
6939 -- f) If the subprogram is marked Inline_Always, then even if it returns
6940 -- an unconstrained type the call does not require use of the secondary
6941 -- stack. However, inlining will only take place if the body to inline
6942 -- is already present. It may not be available if e.g. the subprogram is
6943 -- declared in a child instance.
6945 -- g) If the subprogram is a static expression function and the call is
6946 -- a static call (the actuals are all static expressions), then we never
6947 -- want to create a transient scope (this could occur in the case of a
6948 -- static string-returning call).
6954 then
6962 then
6965 -- A return statement from an ignored Ghost function does not use the
6966 -- secondary stack (or any other one).
6968 elsif Expander_Active
6972 then
6975 -- If the call appears within the bounds of a loop, it will be
6976 -- rewritten and reanalyzed, nothing left to do here.
6983 -- A protected function cannot be called within the definition of the
6984 -- enclosing protected type, unless it is part of a pre/postcondition
6985 -- on another protected operation. This may appear in the entry wrapper
6986 -- created for an entry with preconditions.
6991 and then not In_Spec_Expression
6993 then
6994 Error_Msg_NE
6998 -- Propagate interpretation to actuals, and add default expressions
6999 -- where needed.
7004 -- Overloaded literals are rewritten as function calls, for purpose of
7005 -- resolution. After resolution, we can replace the call with the
7006 -- literal itself.
7012 -- Avoid validation, since it is a static function call
7018 -- If the subprogram is not global, then kill all saved values and
7019 -- checks. This is a bit conservative, since in many cases we could do
7020 -- better, but it is not worth the effort. Similarly, we kill constant
7021 -- values. However we do not need to do this for internal entities
7022 -- (unless they are inherited user-defined subprograms), since they
7023 -- are not in the business of molesting local values.
7025 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
7026 -- kill all checks and values for calls to global subprograms. This
7027 -- takes care of the case where an access to a local subprogram is
7028 -- taken, and could be passed directly or indirectly and then called
7029 -- from almost any context.
7031 -- Note: we do not do this step till after resolving the actuals. That
7032 -- way we still take advantage of the current value information while
7033 -- scanning the actuals.
7035 -- We suppress killing values if we are processing the nodes associated
7036 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
7037 -- type kills all the values as part of analyzing the code that
7038 -- initializes the dispatch tables.
7042 or else Suppress_Value_Tracking_On_Call
7047 then
7048 Kill_Current_Values;
7051 -- If we are warning about unread OUT parameters, this is the place to
7052 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7053 -- after the above call to Kill_Current_Values (since that call clears
7054 -- the Last_Assignment field of all local variables).
7059 then
7060 declare
7064 begin
7074 then
7084 -- If the subprogram is a primitive operation, check whether or not
7085 -- it is a correct dispatching call.
7090 -- If the subprogram is an abstract operation, then flag an error
7096 -- If this is a dispatching call, generate the appropriate reference,
7097 -- for better source navigation in GNAT Studio.
7102 -- Normal case, not a dispatching call: generate a call reference
7104 else
7112 -- Check for violation of restriction No_Specific_Termination_Handlers
7113 -- and warn on a potentially blocking call to Abort_Task.
7117 or else
7119 then
7126 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7127 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7128 -- need to check the second argument to determine whether it is an
7129 -- absolute or relative timing event.
7134 then
7138 -- Issue an error for a call to an eliminated subprogram. This routine
7139 -- will not perform the check if the call appears within a default
7140 -- expression.
7144 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7145 -- class-wide and the call dispatches on result in a context that does
7146 -- not provide a tag, the call raises Program_Error.
7149 and then In_Instance
7154 then
7155 -- Verify that none of the formals are controlling
7157 declare
7161 begin
7183 -- Check for calling a function with OUT or IN OUT parameter when the
7184 -- calling context (us right now) is not Ada 2012, so does not allow
7185 -- OUT or IN OUT parameters in function calls. Functions declared in
7186 -- a predefined unit are OK, as they may be called indirectly from a
7187 -- user-declared instantiation.
7193 then
7198 -- Check the dimensions of the actuals in the call. For function calls,
7199 -- propagate the dimensions from the returned type to N.
7203 -- Check unreachable code after calls to procedures with No_Return
7209 -- All done, evaluate call and deal with elaboration issues
7217 -- Annotate the tree by creating a call marker in case the original call
7218 -- is transformed by expansion. The call marker is automatically saved
7219 -- for later examination by the ABE Processing phase.
7227 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7228 -- expression function, then we want to "inline" the call, replacing
7229 -- it with the folded static result. This is not done if the checking
7230 -- for a potentially static expression is enabled or if an error has
7231 -- been posted on the call (which may be due to the check for recursive
7232 -- calls, in which case we don't want to fall into infinite recursion
7233 -- when doing the inlining).
7235 if not Checking_Potentially_Static_Expression
7239 then
7242 -- In GNATprove mode, expansion is disabled, but we want to inline some
7243 -- subprograms to facilitate formal verification. Indirect calls through
7244 -- a subprogram type or within a generic cannot be inlined. Inlining is
7245 -- performed only for calls subject to SPARK_Mode on.
7247 elsif GNATprove_Mode
7250 and then not Inside_A_Generic
7251 then
7258 -- Nothing to do if the subprogram is not eligible for inlining in
7259 -- GNATprove mode, or inlining is disabled with switch -gnatdm
7263 or else Debug_Flag_M
7264 then
7267 -- Calls cannot be inlined inside assertions, as GNATprove treats
7268 -- assertions as logic expressions. Only issue a message when the
7269 -- body has been seen, otherwise this leads to spurious messages
7270 -- on expression functions.
7273 Cannot_Inline
7277 -- Calls cannot be inlined inside default expressions
7280 Cannot_Inline
7283 -- Calls cannot be inlined inside quantified expressions, which
7284 -- are left in expression form for GNATprove. Since these
7285 -- expressions are only preanalyzed, we need to detect the failure
7286 -- to inline outside of the case for Full_Analysis below.
7289 Cannot_Inline
7292 -- Inlining should not be performed during preanalysis
7296 -- Do not inline calls inside expression functions or functions
7297 -- generated by the front end for subtype predicates, as this
7298 -- would prevent interpreting them as logical formulas in
7299 -- GNATprove. Only issue a message when the body has been seen,
7300 -- otherwise this leads to spurious messages on callees that
7301 -- are themselves expression functions.
7304 and then
7309 then
7312 then
7314 Cannot_Inline
7319 Cannot_Inline
7324 Cannot_Inline
7328 else
7329 Cannot_Inline
7335 -- Cannot inline a call inside the definition of a record type,
7336 -- typically inside the constraints of the type. Calls in
7337 -- default expressions are also not inlined, but this is
7338 -- filtered out above when testing In_Default_Expr.
7341 Cannot_Inline
7344 -- With the one-pass inlining technique, a call cannot be
7345 -- inlined if the corresponding body has not been seen yet.
7348 Cannot_Inline
7351 -- Nothing to do if there is no body to inline, indicating that
7352 -- the subprogram is not suitable for inlining in GNATprove
7353 -- mode.
7358 -- Calls cannot be inlined inside potentially unevaluated
7359 -- expressions, as this would create complex actions inside
7360 -- expressions, that are not handled by GNATprove.
7363 Cannot_Inline
7367 -- Calls cannot be inlined inside the conditions of while
7368 -- loops, as this would create complex actions inside
7369 -- the condition, that are not handled by GNATprove.
7372 Cannot_Inline
7375 -- Do not inline calls which would possibly lead to missing a
7376 -- type conversion check on an input parameter.
7379 Cannot_Inline
7383 -- Otherwise, inline the call, issuing an info message when
7384 -- -gnatd_f is set.
7386 else
7388 Error_Msg_NE
7399 -----------------------------
7400 -- Resolve_Case_Expression --
7401 -----------------------------
7409 begin
7423 -- When the expression is of a scalar subtype different from the
7424 -- result subtype, then insert a conversion to ensure the generation
7425 -- of a constraint check.
7435 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7436 -- dynamically tagged must be known statically.
7444 Error_Msg_N
7458 -------------------------------
7459 -- Resolve_Character_Literal --
7460 -------------------------------
7466 begin
7467 -- Verify that the character does belong to the type of the context
7472 -- Wide_Wide_Character literals must always be defined, since the set
7473 -- of wide wide character literals is complete, i.e. if a character
7474 -- literal is accepted by the parser, then it is OK for wide wide
7475 -- character (out of range character literals are rejected).
7480 -- Always accept character literal for type Any_Character, which
7481 -- occurs in error situations and in comparisons of literals, both
7482 -- of which should accept all literals.
7487 -- For Standard.Character or a type derived from it, check that the
7488 -- literal is in range.
7495 -- For Standard.Wide_Character or a type derived from it, check that the
7496 -- literal is in range.
7503 -- If the entity is already set, this has already been resolved in a
7504 -- generic context, or comes from expansion. Nothing else to do.
7509 -- Otherwise we have a user defined character type, and we can use the
7510 -- standard visibility mechanisms to locate the referenced entity.
7512 else
7525 -- If we fall through, then the literal does not match any of the
7526 -- entries of the enumeration type. This isn't just a constraint error
7527 -- situation, it is an illegality (see RM 4.2).
7529 Error_Msg_NE
7533 ---------------------------
7534 -- Resolve_Comparison_Op --
7535 ---------------------------
7537 -- The operands must have compatible types and the boolean context does not
7538 -- participate in the resolution. The first pass verifies that the operands
7539 -- are not ambiguous and sets their type correctly, or to Any_Type in case
7540 -- of ambiguity. If both operands are strings or aggregates, then they are
7541 -- ambiguous even if they carry a single (universal) type.
7549 begin
7558 -- Deal with explicit ambiguity of operands
7567 -- Deal with other error cases
7571 T = Any_Character
7572 then
7575 else
7583 -- Resolve the operands if types OK
7592 -- Check comparison on unordered enumeration
7596 Error_Msg_NE
7606 --------------------------------
7607 -- Resolve_Declare_Expression --
7608 --------------------------------
7610 procedure Resolve_Declare_Expression
7613 is
7620 -- Use a tree traversal to replace each occurrence of the name of
7621 -- a local object declared in the construct, with the corresponding
7622 -- entity. This replaces the usual way to perform name capture by
7623 -- visibility, because it is not possible to place on the scope
7624 -- stack the fake scope created for the analysis of the local
7625 -- declarations; such a scope conflicts with the transient scopes
7626 -- that may be generated if the expression includes function calls
7627 -- requiring finalization.
7629 -------------------
7630 -- Replace_Local --
7631 -------------------
7634 begin
7635 -- The identifier may be the prefix of a selected component,
7636 -- but not a selector name, because the local entities do not
7637 -- have a scope that can be named: a selected component whose
7638 -- selector is a homonym of a local entity must denote some
7639 -- global entity.
7644 and then
7647 then
7657 -- Start of processing for Resolve_Declare_Expression
7659 begin
7665 N_Object_Declaration | N_Object_Renaming_Declaration
7667 then
7671 -- Traverse the expression to replace references to local
7672 -- variables that occur within declarations of the
7673 -- declare_expression.
7675 declare
7677 begin
7688 -- The end of the declarative list is a freeze point for the
7689 -- local declarations.
7700 -----------------------------------
7701 -- Resolve_Dependent_Expression --
7702 -----------------------------------
7704 procedure Resolve_Dependent_Expression
7708 is
7709 begin
7710 -- RM 4.5.7(8/3) says that the expected type of dependent expressions is
7711 -- that of the conditional expression but RM 4.5.7(10/3) forces the type
7712 -- of the conditional expression without changing the expected type (the
7713 -- expected type of the operand of a type conversion is any type), so we
7714 -- may have a gap between these two types that is bridged by the dynamic
7715 -- semantics specified by RM 4.5.7(20/3) with the associated legality
7716 -- rule RM 4.5.7(16/3) that will be automatically enforced.
7720 then
7723 else
7728 -----------------------------------------
7729 -- Resolve_Discrete_Subtype_Indication --
7730 -----------------------------------------
7732 procedure Resolve_Discrete_Subtype_Indication
7735 is
7739 begin
7747 else
7757 Error_Msg_NE
7760 -- Rewrite the constraint as a range of Typ
7761 -- to allow compilation to proceed further.
7773 else
7777 -- Additionally, we must check that the bounds are compatible
7778 -- with the given subtype, which might be different from the
7779 -- type of the context.
7783 -- ??? If the above check statically detects a Constraint_Error
7784 -- it replaces the offending bound(s) of the range R with a
7785 -- Constraint_Error node. When the itype which uses these bounds
7786 -- is frozen the resulting call to Duplicate_Subexpr generates
7787 -- a new temporary for the bounds.
7789 -- Unfortunately there are other itypes that are also made depend
7790 -- on these bounds, so when Duplicate_Subexpr is called they get
7791 -- a forward reference to the newly created temporaries and Gigi
7792 -- aborts on such forward references. This is probably sign of a
7793 -- more fundamental problem somewhere else in either the order of
7794 -- itype freezing or the way certain itypes are constructed.
7796 -- To get around this problem we call Remove_Side_Effects right
7797 -- away if either bounds of R are a Constraint_Error.
7799 declare
7803 begin
7819 -------------------------
7820 -- Resolve_Entity_Name --
7821 -------------------------
7823 -- Used to resolve identifiers and expanded names
7826 function Is_Assignment_Or_Object_Expression
7829 -- Determine whether node Context denotes an assignment statement or an
7830 -- object declaration whose expression is node Expr.
7833 -- Determine whether Expr is part of an N_Attribute_Reference
7834 -- expression.
7836 ----------------------------------------
7837 -- Is_Assignment_Or_Object_Expression --
7838 ----------------------------------------
7840 function Is_Assignment_Or_Object_Expression
7843 is
7844 begin
7847 then
7850 -- Check whether a construct that yields a name is the expression of
7851 -- an assignment statement or an object declaration.
7854 | N_Explicit_Dereference
7855 | N_Indexed_Component
7856 | N_Selected_Component
7857 | N_Slice
7859 or else
7861 | N_Unchecked_Type_Conversion
7863 then
7864 return
7865 Is_Assignment_Or_Object_Expression
7869 -- Otherwise the context is not an assignment statement or an object
7870 -- declaration.
7872 else
7877 -----------------------------
7878 -- Is_Attribute_Expression --
7879 -----------------------------
7883 begin
7888 -- Prevent the search from going too far
7900 -- Local variables
7905 -- Start of processing for Resolve_Entity_Name
7907 begin
7908 -- If garbage from errors, set to Any_Type and return
7915 -- Replace named numbers by corresponding literals. Note that this is
7916 -- the one case where Resolve_Entity_Name must reset the Etype, since
7917 -- it is currently marked as universal.
7927 -- For enumeration literals, we need to make sure that a proper style
7928 -- check is done, since such literals are overloaded, and thus we did
7929 -- not do a style check during the first phase of analysis.
7935 -- Case of (sub)type name appearing in a context where an expression
7936 -- is expected. This is legal if occurrence is a current instance.
7937 -- See RM 8.6 (17/3). It is also legal if the expression is
7938 -- part of a choice pattern for a case stmt/expr having a
7939 -- non-discrete selecting expression.
7945 -- Any other use is an error
7947 else
7948 Error_Msg_N
7952 -- Check discriminant use if entity is discriminant in current scope,
7953 -- i.e. discriminant of record or concurrent type currently being
7954 -- analyzed. Uses in corresponding body are unrestricted.
7959 then
7962 -- A parameterless generic function cannot appear in a context that
7963 -- requires resolution.
7968 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7969 -- array types (i.e. bounds and length) are legal.
7977 or else Is_Assignment_Or_Object_Expression
7980 then
7985 -- In all other cases, just do the possible static evaluation
7987 else
7988 -- A deferred constant that appears in an expression must have a
7989 -- completion, unless it has been removed by in-place expansion of
7990 -- an aggregate. A constant that is a renaming does not need
7991 -- initialization.
7997 and then not In_Spec_Expression
8000 then
8004 then
8006 else
8007 Error_Msg_N
8017 -- When the entity appears in a parameter association, retrieve the
8018 -- related subprogram call.
8026 -- The following checks are only relevant when SPARK_Mode is on as
8027 -- they are not standard Ada legality rules.
8031 -- An effectively volatile object for reading must appear in
8032 -- non-interfering context (SPARK RM 7.1.3(10)).
8036 and then
8038 then
8039 SPARK_Msg_N
8044 -- Check for possible elaboration issues with respect to reads of
8045 -- variables. The act of renaming the variable is not considered a
8046 -- read as it simply establishes an alias.
8048 if Legacy_Elaboration_Checks
8050 and then Dynamic_Elaboration_Checks
8052 then
8057 -- The variable may eventually become a constituent of a single
8058 -- protected/task type. Record the reference now and verify its
8059 -- legality when analyzing the contract of the variable
8060 -- (SPARK RM 9.3).
8066 -- A Ghost entity must appear in a specific context
8073 -- We may be resolving an entity within expanded code, so a reference to
8074 -- an entity should be ignored when calculating effective use clauses to
8075 -- avoid inappropriate marking.
8082 -------------------
8083 -- Resolve_Entry --
8084 -------------------
8096 -- If the bounds of the entry family being called depend on task
8097 -- discriminants, build a new index subtype where a discriminant is
8098 -- replaced with the value of the discriminant of the target task.
8099 -- The target task is the prefix of the entry name in the call.
8101 -----------------------
8102 -- Actual_Index_Type --
8103 -----------------------
8113 -- If the bound is given by a discriminant, replace with a reference
8114 -- to the discriminant of the same name in the target task. If the
8115 -- entry name is the target of a requeue statement and the entry is
8116 -- in the current protected object, the bound to be used is the
8117 -- discriminal of the object (see Apply_Range_Check for details of
8118 -- the transformation).
8120 -----------------------------
8121 -- Actual_Discriminant_Ref --
8122 -----------------------------
8128 begin
8133 then
8139 then
8140 -- Note: here Bound denotes a discriminant of the corresponding
8141 -- record type tskV, whose discriminal is a formal of the
8142 -- init-proc tskVIP. What we want is the body discriminal,
8143 -- which is associated to the discriminant of the original
8144 -- concurrent type tsk.
8146 return New_Occurrence_Of
8149 else
8150 Ref :=
8160 -- Start of processing for Actual_Index_Type
8162 begin
8165 then
8168 else
8182 -- Start of processing for Resolve_Entry
8184 begin
8185 -- Find name of entry being called, and resolve prefix of name with its
8186 -- own type. The prefix can be overloaded, and the name and signature of
8187 -- the entry must be taken into account.
8191 -- Case of dealing with entry family within the current tasks
8195 else
8201 -- Entry call to an entry (or entry family) in the current task. This
8202 -- is legal even though the task will deadlock. Rewrite as call to
8203 -- current task.
8205 -- This can also be a call to an entry in an enclosing task. If this
8206 -- is a single task, we have to retrieve its name, because the scope
8207 -- of the entry is the task type, not the object. If the enclosing
8208 -- task is a task type, the identity of the task is given by its own
8209 -- self variable.
8211 -- Finally this can be a requeue on an entry of the same task or
8212 -- protected object.
8219 then
8220 -- S is an enclosing task or protected object. The concurrent
8221 -- declaration has been converted into a type declaration, and
8222 -- the object itself has an object declaration that follows
8223 -- the type in the same declarative part.
8235 -- Call to current task. Will be transformed into call to Self
8242 New_N :=
8245 Selector_Name =>
8252 then
8253 -- Use the entry name (which must be unique at this point) to find
8254 -- the prefix that returns the corresponding task/protected type.
8256 declare
8262 begin
8284 -- We do not resolve the prefix because an Entry_Family has no type,
8285 -- although it has the semantics of an array since it can be indexed.
8286 -- In order to perform the associated range check, we would need to
8287 -- build an array type on the fly and set it on the prefix, but this
8288 -- would be wasteful since only the index type matters. Therefore we
8289 -- attach this index type directly, so that Actual_Index_Expression
8290 -- can pick it up later in order to generate the range check.
8297 -- Generate a reference for the index when it denotes an entity
8303 -- Up to this point the expression could have been the actual in a
8304 -- simple entry call, and be given by a named association.
8308 else
8314 ------------------------
8315 -- Resolve_Entry_Call --
8316 ------------------------
8327 begin
8328 -- We kill all checks here, because it does not seem worth the effort to
8329 -- do anything better, an entry call is a big operation.
8331 Kill_All_Checks;
8333 -- Processing of the name is similar for entry calls and protected
8334 -- operation calls. Once the entity is determined, we can complete
8335 -- the resolution of the actuals.
8337 -- The selector may be overloaded, in the case of a protected object
8338 -- with overloaded functions. The type of the context is used for
8339 -- resolution.
8344 then
8345 declare
8349 begin
8368 -- Simple entry or protected operation call
8381 -- Call to member of entry family
8388 -- We cannot in general check the maximum depth of protected entry calls
8389 -- at compile time. But we can tell that any protected entry call at all
8390 -- violates a specified nesting depth of zero.
8396 -- Use context type to disambiguate a protected function that can be
8397 -- called without actuals and that returns an array type, and where the
8398 -- argument list may be an indexing of the returned value.
8403 and then
8409 and then
8410 Covers
8413 then
8414 declare
8417 begin
8418 Index_Node :=
8420 Prefix =>
8424 -- Since we are correcting a node classification error made by the
8425 -- parser, we call Replace rather than Rewrite.
8439 then
8440 -- Note the entity being called before rewriting the call, so that
8441 -- it appears used at this point.
8445 -- Rewrite as call to the precondition wrapper, adding the task
8446 -- object to the list of actuals. If the call is to a member of an
8447 -- entry family, include the index as well.
8449 declare
8453 begin
8462 New_Call :=
8464 Name =>
8469 -- Preanalyze and resolve new call. Current procedure is called
8470 -- from Resolve_Call, after which expansion will take place.
8477 -- The operation name may have been overloaded. Order the actuals
8478 -- according to the formals of the resolved entity, and set the return
8479 -- type to that of the operation.
8486 -- Reset the Is_Overloaded flag, since resolution is now completed
8488 -- Simple entry call
8493 -- Call to a member of an entry family
8503 -- Create a call reference to the entry
8511 -- Verify that a procedure call cannot masquerade as an entry
8512 -- call where an entry call is expected.
8517 then
8522 then
8527 then
8532 -- After resolution, entry calls and protected procedure calls are
8533 -- changed into entry calls, for expansion. The structure of the node
8534 -- does not change, so it can safely be done in place. Protected
8535 -- function calls must keep their structure because they are
8536 -- subexpressions.
8540 -- A protected operation that is not a function may modify the
8541 -- corresponding object, and cannot apply to a constant. If this
8542 -- is an internal call, the prefix is the type itself.
8548 then
8549 Error_Msg_N
8551 Entry_Name);
8554 declare
8557 begin
8558 Entry_Call :=
8563 -- Inherit relevant attributes from the original call
8565 Set_First_Named_Actual
8568 Set_Is_Elaboration_Checks_OK_Node
8571 Set_Is_Elaboration_Warnings_OK_Node
8574 Set_Is_SPARK_Mode_On_Node
8581 -- Protected functions can return on the secondary stack, in which case
8582 -- we must trigger the transient scope mechanism.
8584 elsif Expander_Active
8586 then
8590 -- Now we know that this is not a call to a function that returns an
8591 -- array type; moreover, we know the name of the called entry. Detect
8592 -- overlapping actuals, just like for a subprogram call.
8597 -------------------------
8598 -- Resolve_Equality_Op --
8599 -------------------------
8601 -- The operands must have compatible types and the boolean context does not
8602 -- participate in the resolution. The first pass verifies that the operands
8603 -- are not ambiguous and sets their type correctly, or to Any_Type in case
8604 -- of ambiguity. If both operands are strings, aggregates, allocators, or
8605 -- null, they are ambiguous even if they carry a single (universal) type.
8615 and then not
8617 -- Whether this is a call to the implicit inequality operator created
8618 -- for a user-defined operator that is not an intrinsic subprogram, in
8619 -- which case we need to skip some processing.
8624 -- For any object, '[Unchecked_]Access of such object can never be
8625 -- passed as an operand to the Universal_Access equality operators.
8626 -- This is so because the expected type for Obj'Access in a call to
8627 -- these operators, whose formals are of type Universal_Access, is
8628 -- Universal_Access, and Universal_Access does not have a designated
8629 -- type. For more details, see RM 3.10.2(2/2) and 6.4.1(3).
8632 -- Check RM 4.5.2(9.6/2) on the given designated object types
8635 -- Check RM 4.5.2(9.7/2) on the given designated subprogram types
8638 -- The resolution rule for if expressions requires that each such must
8639 -- have a unique type. This means that if several dependent expressions
8640 -- are of a non-null anonymous access type, and the context does not
8641 -- impose an expected type (as can be the case in an equality operation)
8642 -- the expression must be rejected.
8645 -- Attempt to explain the nature of a redundant comparison with True. If
8646 -- the expression N is too complex, this routine issues a general error
8647 -- message.
8650 -- In the case of allocators and access attributes, the context must
8651 -- provide an indication of the specific access type to be used. If
8652 -- one operand is of such a "generic" access type, check whether there
8653 -- is a specific visible access type that has the same designated type.
8654 -- This is semantically dubious, and of no interest to any real code,
8655 -- but c48008a makes it all worthwhile.
8658 -- Returns True iff the parent node is a and/or/xor operation that
8659 -- could be the cause of confused priorities. Note that if the not is
8660 -- in parens, then False is returned.
8662 ----------------------------
8663 -- Check_Access_Attribute --
8664 ----------------------------
8667 begin
8670 then
8671 Error_Msg_N
8677 -----------------------------------
8678 -- Check_Designated_Object_Types --
8679 -----------------------------------
8682 begin
8686 then
8687 Error_Msg_N
8695 ---------------------------------------
8696 -- Check_Designated_Subprogram_Types --
8697 ---------------------------------------
8700 begin
8702 Error_Msg_N
8710 -------------------------
8711 -- Check_If_Expression --
8712 -------------------------
8718 begin
8725 then
8731 ------------------------
8732 -- Explain_Redundancy --
8733 ------------------------
8740 begin
8743 -- Strip the operand down to an entity
8745 loop
8748 else
8753 -- The construct denotes an entity
8758 -- Do not generate an error message when the comparison is done
8759 -- against the enumeration literal Standard.True.
8763 -- Build a customized error message
8790 -- The construct is too complex to disect, issue a general message
8792 else
8797 -----------------------------
8798 -- Find_Unique_Access_Type --
8799 -----------------------------
8806 begin
8808 then
8812 then
8814 else
8826 then
8839 ----------------------------------
8840 -- Suspicious_Prio_For_Equality --
8841 ----------------------------------
8846 begin
8847 -- Check if parent node is one of and/or/xor, not parenthesized
8848 -- explicitly, and its own parent is not of this kind. Otherwise,
8849 -- it's a case of chained Boolean conditions which is likely well
8850 -- parenthesized.
8855 then
8856 declare
8860 else
8862 begin
8863 -- Compar may have been rewritten, for example from (a /= b)
8864 -- into not (a = b). Use the Original_Node instead.
8868 -- If the other argument of the and/or/xor is also a
8869 -- comparison, or another and/or/xor then most likely
8870 -- the priorities are correctly set.
8875 else
8880 -- Start of processing for Resolve_Equality_Op
8882 begin
8891 -- Deal with explicit ambiguity of operands, unless this is a call
8892 -- to the implicit inequality operator created for a user-defined
8893 -- operator that is not an intrinsic subprogram, since the common
8894 -- resolution of operands done here does not apply to it.
8896 if not Implicit_NE_For_User_Defined_Operator
8898 then
8902 else
8904 -- For Ada 2022, check for user-defined literals when the type has
8905 -- the appropriate aspect.
8917 -- Deal with other error cases
8921 T = Any_Character
8922 then
8925 else
8934 then
8943 -- If expressions must have a single type, and if the context does
8944 -- not impose one the dependent expressions cannot be anonymous
8945 -- access types.
8947 -- Why no similar processing for case expressions???
8952 then
8957 -- RM 4.5.2(9.5/2): At least one of the operands of the equality
8958 -- operators for universal_access shall be of type universal_access,
8959 -- or both shall be of access-to-object types, or both shall be of
8960 -- access-to-subprogram types (RM 4.5.2(9.5/2)).
8965 then
8966 -- RM 4.5.2(9.6/2): When both are of access-to-object types, the
8967 -- designated types shall be the same or one shall cover the other
8968 -- and if the designated types are elementary or array types, then
8969 -- the designated subtypes shall statically match.
8973 then
8974 Check_Designated_Object_Types
8977 -- RM 4.5.2(9.7/2): When both are of access-to-subprogram types,
8978 -- the designated profiles shall be subtype conformant.
8982 then
8983 Check_Designated_Subprogram_Types
8988 -- Check another case of equality operators for universal_access
8998 -- AI12-0413: user-defined primitive equality of an untagged record
8999 -- type hides the predefined equality operator, including within a
9000 -- generic, and if it is declared abstract, results in an illegal
9001 -- instance if the operator is used in the spec, or in the raising
9002 -- of Program_Error if used in the body of an instance.
9005 and then In_Instance
9007 then
9008 declare
9013 begin
9017 then
9023 else
9033 -- If the unique type is a class-wide type then it will be expanded
9034 -- into a dispatching call to the predefined primitive. Therefore we
9035 -- check here for potential violation of such restriction.
9041 -- Only warn for redundant equality comparison to True for objects
9042 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
9043 -- other expressions, it may be a matter of preference to write
9044 -- "Expr = True" or "Expr".
9046 if Warn_On_Redundant_Constructs
9051 and then
9053 or else
9055 then
9056 Error_Msg_N -- CODEFIX
9061 -- Warn on a (in)equality between boolean values which is not
9062 -- parenthesized when the parent expression is one of and/or/xor, as
9063 -- this is interpreted as (a = b) op c where most likely a = (b op c)
9064 -- was intended. Do not generate a warning in generic instances, as
9065 -- the problematic expression may be implicitly parenthesized in
9066 -- the generic itself if one of the operators is a generic formal.
9067 -- Also do not generate a warning for generated equality, for
9068 -- example from rewritting a membership test.
9070 if Warn_On_Questionable_Missing_Parens
9071 and then not In_Instance
9074 and then Suspicious_Prio_For_Equality
9075 then
9084 -- Unless this is a call to the implicit inequality operator created
9085 -- for a user-defined operator that is not an intrinsic subprogram,
9086 -- try to fold the operation.
9094 then
9100 ----------------------------------
9101 -- Resolve_Explicit_Dereference --
9102 ----------------------------------
9110 -- The candidate prefix type, if overloaded
9115 begin
9119 -- A useful optimization: check whether the dereference denotes an
9120 -- element of a container, and if so rewrite it as a call to the
9121 -- corresponding Element function.
9123 -- Disabled for now, on advice of ARG. A more restricted form of the
9124 -- predicate might be acceptable ???
9126 -- if Is_Container_Element (N) then
9127 -- return;
9128 -- end if;
9132 -- Use the context type to select the prefix that has the correct
9133 -- designated type. Keep the first match, which will be the inner-
9134 -- most.
9141 then
9146 -- Remove access types that do not match, but preserve access
9147 -- to subprogram interpretations, in case a further dereference
9148 -- is needed (see below).
9161 else
9162 -- If no interpretation covers the designated type of the prefix,
9163 -- this is the pathological case where not all implementations of
9164 -- the prefix allow the interpretation of the node as a call. Now
9165 -- that the expected type is known, Remove other interpretations
9166 -- from prefix, rewrite it as a call, and resolve again, so that
9167 -- the proper call node is generated.
9178 New_N :=
9180 Name =>
9191 -- If not overloaded, resolve P with its own type
9193 else
9197 -- If the prefix might be null, add an access check
9201 then
9205 -- If the designated type is a packed unconstrained array type, and the
9206 -- explicit dereference is not in the context of an attribute reference,
9207 -- then we must compute and set the actual subtype, since it is needed
9208 -- by Gigi. The reason we exclude the attribute case is that this is
9209 -- handled fine by Gigi, and in fact we use such attributes to build the
9210 -- actual subtype. We also exclude generated code (which builds actual
9211 -- subtypes directly if they are needed).
9217 then
9223 -- Note: No Eval processing is required for an explicit dereference,
9224 -- because such a name can never be static.
9228 -------------------------------------
9229 -- Resolve_Expression_With_Actions --
9230 -------------------------------------
9235 -- True if Act is an action of a declare_expression that is allowed in a
9236 -- static declare_expression.
9239 -- True if all actions of N are allowed in a static declare_expression.
9242 -- Expr is an expression with compile-time-known value. This returns the
9243 -- literal node that reprsents that value.
9245 -------------------
9246 -- OK_For_Static --
9247 -------------------
9250 begin
9255 then
9265 -- No other declarations, nor even pragmas, are allowed in a
9266 -- declare expression, so if we see something else, it must be
9267 -- an internally generated expression_with_actions.
9274 -----------------------
9275 -- All_OK_For_Static --
9276 -----------------------
9280 begin
9292 -----------------
9293 -- Get_Literal --
9294 -----------------
9299 begin
9304 else
9313 pragma Assert
9319 -- Local variables
9323 -- Start of processing for Resolve_Expression_With_Actions
9325 begin
9332 -- If the value of the expression is known at compile time, and all
9333 -- of the actions (if any) are suitable, then replace the declare
9334 -- expression with its expression. This allows the declare expression
9335 -- as a whole to be static if appropriate. See AI12-0368.
9341 Rewrite
9348 ----------------------------------
9349 -- Resolve_Generalized_Indexing --
9350 ----------------------------------
9354 begin
9359 ---------------------------
9360 -- Resolve_If_Expression --
9361 ---------------------------
9367 -- When a dependent expression is of a subtype different from
9368 -- the context subtype, then insert a qualification to ensure
9369 -- the generation of a constraint check. This was previously
9370 -- for scalar types. For array types apply a length check, given
9371 -- that the context in general allows sliding, while a qualified
9372 -- expression forces equality of bounds.
9374 -----------------
9375 -- Apply_Check --
9376 -----------------
9382 begin
9387 or else Inside_A_Generic
9388 then
9394 else
9404 -- Local variables
9410 -- So in most cases the type of the if_expression and of its
9411 -- dependent expressions is that of the context. However, if
9412 -- the expression is the index of an Indexed_Component, we must
9413 -- ensure that a proper index check is applied, rather than a
9414 -- range check on the index type (which might be discriminant
9415 -- dependent). In this case we resolve with the base type of the
9416 -- index type, and the index check is generated in the resolution
9417 -- of the indexed_component above.
9419 -- Start of processing for Resolve_If_Expression
9421 begin
9422 -- Defend against malformed expressions
9431 then
9434 else
9454 -- If ELSE expression present, just resolve using the determined type
9462 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9463 -- dynamically tagged must be known statically.
9468 then
9474 -- If no ELSE expression is present, root type must be Standard.Boolean
9475 -- and we provide a Standard.True result converted to the appropriate
9476 -- Boolean type (in case it is a derived boolean type).
9479 Else_Expr :=
9484 else
9498 ----------------------------------
9499 -- Resolve_Implicit_Dereference --
9500 ----------------------------------
9505 begin
9506 -- In an instance the proper view may not always be correct for
9507 -- private types, see e.g. Sem_Type.Covers for similar handling.
9512 and then In_Instance
9513 then
9524 -------------------------------
9525 -- Resolve_Indexed_Component --
9526 -------------------------------
9534 begin
9542 -- Use the context type to select the prefix that yields the correct
9543 -- component type.
9545 declare
9551 begin
9558 and then
9559 Covers
9562 then
9571 else
9577 else
9588 else
9595 -- If the prefix's type is an access type, get to the real array type.
9596 -- Note: we do not apply an access check because an explicit dereference
9597 -- will be introduced later, and the check will happen there.
9603 -- If name was overloaded, set component type correctly now.
9604 -- If a misplaced call to an entry family (which has no index types)
9605 -- return. Error will be diagnosed from calling context.
9609 else
9616 -- The prefix may have resolved to a string literal, in which case its
9617 -- etype has a special representation. This is only possible currently
9618 -- if the prefix is a static concatenation, written in functional
9619 -- notation.
9624 else
9639 -- Do not generate the warning on suspicious index if we are analyzing
9640 -- package Ada.Tags; otherwise we will report the warning with the
9641 -- Prims_Ptr field of the dispatch table.
9644 or else not
9646 then
9651 -- If the array type is atomic and the component is not, then this is
9652 -- worth a warning before Ada 2022, since we have a situation where the
9653 -- access to the component may cause extra read/writes of the atomic
9654 -- object, or partial word accesses, both of which may be unexpected.
9660 and then Has_Atomic_Components
9664 then
9665 Error_Msg_N
9667 Error_Msg_N
9672 -----------------------------
9673 -- Resolve_Integer_Literal --
9674 -----------------------------
9677 begin
9682 -----------------------------------------
9683 -- Resolve_Interpolated_String_Literal --
9684 -----------------------------------------
9687 is
9690 begin
9696 -- Resolve string elements using the context type; for interpolated
9697 -- expressions there is no need to check if their type has a suitable
9698 -- image function because under Ada 2022 all the types have such
9699 -- function available.
9711 --------------------------------
9712 -- Resolve_Intrinsic_Operator --
9713 --------------------------------
9722 -- If the operand is a literal, it cannot be the expression in a
9723 -- conversion. Use a qualified expression instead.
9725 ---------------------
9726 -- Convert_Operand --
9727 ---------------------
9733 begin
9735 Res :=
9741 else
9748 -- Start of processing for Resolve_Intrinsic_Operator
9750 begin
9751 -- We must preserve the original entity in a generic setting, so that
9752 -- the legality of the operation can be verified in an instance.
9767 -- If the result or operand types are private, rewrite with unchecked
9768 -- conversions on the operands and the result, to expose the proper
9769 -- underlying numeric type.
9774 then
9779 else
9800 then
9801 -- Add explicit conversion where needed, and save interpretations in
9802 -- case operands are overloaded.
9809 else
9815 else
9825 else
9830 --------------------------------------
9831 -- Resolve_Intrinsic_Unary_Operator --
9832 --------------------------------------
9834 procedure Resolve_Intrinsic_Unary_Operator
9837 is
9842 begin
9861 else
9866 ------------------------
9867 -- Resolve_Logical_Op --
9868 ------------------------
9873 begin
9876 -- Predefined operations on scalar types yield the base type. On the
9877 -- other hand, logical operations on arrays yield the type of the
9878 -- arguments (and the context).
9882 else
9886 -- The following test is required because the operands of the operation
9887 -- may be literals, in which case the resulting type appears to be
9888 -- compatible with a signed integer type, when in fact it is compatible
9889 -- only with modular types. If the context itself is universal, the
9890 -- operation is illegal.
9898 Error_Msg_N
9906 then
9910 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
9911 -- is active and the result type is standard Boolean (do not mess with
9912 -- ops that return a nonstandard Boolean type, because something strange
9913 -- is going on).
9915 -- Note: you might expect this replacement to be done during expansion,
9916 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
9917 -- is used, no part of the right operand of an "and" or "or" operator
9918 -- should be executed if the left operand would short-circuit the
9919 -- evaluation of the corresponding "and then" or "or else". If we left
9920 -- the replacement to expansion time, then run-time checks associated
9921 -- with such operands would be evaluated unconditionally, due to being
9922 -- before the condition prior to the rewriting as short-circuit forms
9923 -- during expansion.
9925 if Short_Circuit_And_Or
9928 then
9929 -- Mark the corresponding putative SCO operator as truly a logical
9930 -- (and short-circuit) operator.
9943 -- Case of OR changed to OR ELSE
9945 else
9953 -- Return now, since analysis of the rewritten ops will take care of
9954 -- other reference bookkeeping and expression folding.
9970 ---------------------------------
9971 -- Resolve_Membership_Equality --
9972 ---------------------------------
9977 begin
9978 -- RM 4.5.2(4.1/3): if the type is limited, then it shall have a visible
9979 -- primitive equality operator. This means that we can use the regular
9980 -- visibility-based resolution and reset Entity in order to trigger it.
9985 -- RM 4.5.2(28.1/3): if the type is a record, then the membership test
9986 -- uses the primitive equality for the type [even if it is not visible].
9987 -- We only deal with the untagged case here, because the tagged case is
9988 -- handled uniformly in the expander.
9991 declare
9994 begin
10002 ---------------------------
10003 -- Resolve_Membership_Op --
10004 ---------------------------
10006 -- The context can only be a boolean type, and does not determine the
10007 -- arguments. Arguments should be unambiguous, but the preference rule for
10008 -- universal types applies.
10018 -- Analysis has determined a unique type for the left operand. Use it as
10019 -- the basis to resolve the disjuncts.
10021 ----------------------------
10022 -- Resolve_Set_Membership --
10023 ----------------------------
10028 begin
10029 -- If the left operand is overloaded, find type compatible with not
10030 -- overloaded alternative of the right operand.
10039 else
10044 -- Unclear how to resolve expression if all alternatives are also
10045 -- overloaded.
10051 else
10060 -- Alternative is an expression, a range
10061 -- or a subtype mark.
10065 then
10072 -- Check for duplicates for discrete case
10075 declare
10084 begin
10085 -- Loop checking duplicates. This is quadratic, but giant sets
10086 -- are unlikely in this context so it's a reasonable choice.
10093 | N_Character_Literal
10094 | N_Has_Entity
10095 then
10112 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
10113 -- limited types, evaluation of a membership test uses the predefined
10114 -- equality for the type. This may be confusing to users, and the
10115 -- following warning appears useful for the most common case.
10119 then
10120 Error_Msg_NE
10122 Error_Msg_N
10127 -- Start of processing for Resolve_Membership_Op
10129 begin
10135 Resolve_Set_Membership;
10141 then
10144 -- If the left operand is of a universal numeric type and the right
10145 -- operand is not, we do not resolve the operands to the tested type
10146 -- but to the universal type instead. If not conforming to the letter,
10147 -- it's conforming to the spirit of the specification of membership
10148 -- tests, which are typically used to guard a specific operation and
10149 -- ought not to fail a check in doing so. Without this, in the case of
10151 -- type Small_Length is range 1 .. 16;
10153 -- function Is_Small_String (S : String) return Boolean is
10154 -- begin
10155 -- return S'Length in Small_Length;
10156 -- end;
10158 -- the function Is_Small_String would fail a range check for strings
10159 -- larger than 127 characters.
10161 -- The test on the size is required in GNAT because universal_integer
10162 -- does not cover all the values of all the supported integer types,
10163 -- for example the large values of Long_Long_Long_Unsigned.
10168 or else
10170 and then
10172 or else
10174 then
10177 -- If the right operand is 'Range, we first need to resolve it (to
10178 -- the tested type) so that it is rewritten as an N_Range, before
10179 -- converting its bounds and resolving it again below.
10183 then
10187 -- If the right operand is an N_Range, we convert its bounds to the
10188 -- universal type before resolving it.
10198 -- Ada 2005 (AI-251): Support the following case:
10200 -- type I is interface;
10201 -- type T is tagged ...
10203 -- function Test (O : I'Class) is
10204 -- begin
10205 -- return O in T'Class.
10206 -- end Test;
10208 -- In this case we have nothing else to do. The membership test will be
10209 -- done at run time.
10215 then
10218 else
10222 -- If mixed-mode operations are present and operands are all literal,
10223 -- the only interpretation involves Duration, which is probably not
10224 -- the intention of the programmer.
10239 then
10245 else
10250 -- Here after resolving membership operation
10257 ------------------
10258 -- Resolve_Null --
10259 ------------------
10264 begin
10265 -- Handle restriction against anonymous null access values This
10266 -- restriction can be turned off using -gnatdj.
10268 -- Ada 2005 (AI-231): Remove restriction
10271 and then not Debug_Flag_J
10274 then
10275 -- In the common case of a call which uses an explicitly null value
10276 -- for an access parameter, give specialized error message.
10279 Error_Msg_N
10282 -- Standard message for all other cases (are there any?)
10284 else
10285 Error_Msg_N
10290 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
10291 -- assignment to a null-excluding object.
10296 then
10299 -- Decide whether to generate an if_statement around our
10300 -- null-excluding check to avoid them on certain internal object
10301 -- declarations by looking at the type the current Init_Proc
10302 -- belongs to.
10304 -- Generate:
10305 -- if T1b_skip_null_excluding_check then
10306 -- [constraint_error "access check failed"]
10307 -- end if;
10309 if Needs_Conditional_Null_Excluding_Check
10311 then
10314 Condition =>
10316 New_External_Name
10318 Then_Statements =>
10319 New_List (
10323 -- Otherwise, simply create the check
10325 else
10330 else
10331 Insert_Action
10339 -- In a distributed context, null for a remote access to subprogram may
10340 -- need to be replaced with a special record aggregate. In this case,
10341 -- return after having done the transformation.
10346 then
10350 -- The null literal takes its type from the context
10355 -----------------------
10356 -- Resolve_Op_Concat --
10357 -----------------------
10361 -- We wish to avoid deep recursion, because concatenations are often
10362 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10363 -- operands nonrecursively until we find something that is not a simple
10364 -- concatenation (A in this case). We resolve that, and then walk back
10365 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10366 -- to do the rest of the work at each level. The Parent pointers allow
10367 -- us to avoid recursion, and thus avoid running out of memory. See also
10368 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10373 begin
10374 -- The following code is equivalent to:
10376 -- Resolve_Op_Concat_First (NN, Typ);
10377 -- Resolve_Op_Concat_Arg (N, ...);
10378 -- Resolve_Op_Concat_Rest (N, Typ);
10380 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10381 -- operand is a concatenation.
10383 -- Walk down left operands
10385 loop
10394 -- Now (given the above example) NN is A&B and Op1 is A
10396 -- First resolve Op1 ...
10400 -- ... then walk NN back up until we reach N (where we started), calling
10401 -- Resolve_Op_Concat_Rest along the way.
10403 loop
10410 ---------------------------
10411 -- Resolve_Op_Concat_Arg --
10412 ---------------------------
10414 procedure Resolve_Op_Concat_Arg
10419 is
10423 begin
10425 if Is_Comp
10429 then
10431 else
10435 -- If both Array & Array and Array & Component are visible, there is a
10436 -- potential ambiguity that must be reported.
10441 then
10445 -- If the operation is user-defined and not overloaded use its
10446 -- profile. The operation may be a renaming, in which case it has
10447 -- been rewritten, and we want the original profile.
10452 then
10454 Etype
10458 -- Otherwise an aggregate may match both the array type and the
10459 -- component type.
10461 else
10466 else
10470 then
10471 declare
10476 begin
10481 -- Special-case the error message when the overloading is
10482 -- caused by a function that yields an array and can be
10483 -- called without parameters.
10488 Error_Msg_NE
10490 Error_Msg_NE
10494 else
10502 or else
10504 then
10505 Error_Msg_N -- CODEFIX
10522 then
10523 -- Determine if the out-of-range violation constitutes a
10524 -- warning or an error according to the expression base type,
10525 -- according to Ada 2022 RM 4.9 (35/2).
10528 Apply_Compile_Time_Constraint_Error
10534 Apply_Compile_Time_Constraint_Error
10543 else
10548 else
10555 -----------------------------
10556 -- Resolve_Op_Concat_First --
10557 -----------------------------
10564 begin
10565 -- The parser folds an enormous sequence of concatenations of string
10566 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10567 -- in the right operand. If the expression resolves to a predefined "&"
10568 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10569 -- we give an error. See P_Simple_Expression in Par.Ch4.
10574 then
10589 ----------------------------
10590 -- Resolve_Op_Concat_Rest --
10591 ----------------------------
10597 begin
10606 -- If this is not a static concatenation, but the result is a string
10607 -- type (and not an array of strings) ensure that static string operands
10608 -- have their subtypes properly constructed.
10612 then
10618 ----------------------
10619 -- Resolve_Op_Expon --
10620 ----------------------
10625 begin
10626 -- Catch attempts to do fixed-point exponentiation with universal
10627 -- operands, which is a case where the illegality is not caught during
10628 -- normal operator analysis. This is not done in preanalysis mode
10629 -- since the tree is not fully decorated during preanalysis.
10641 then
10651 then
10660 -- We do the resolution using the base type, because intermediate values
10661 -- in expressions are always of the base type, not a subtype of it.
10666 -- For integer types, right argument must be in Natural range
10681 -- Evaluate the exponentiation operator for dimensioned type
10684 else
10688 -- Set overflow checking bit. Much cleverer code needed here eventually
10689 -- and perhaps the Resolve routines should be separated for the various
10690 -- arithmetic operations, since they will need different processing. ???
10699 --------------------
10700 -- Resolve_Op_Not --
10701 --------------------
10705 -- This function determines if the parent node is a boolean operator or
10706 -- operation (comparison op, membership test, or short circuit form) and
10707 -- the not in question is the left operand of this operation. Note that
10708 -- if the not is in parens, then false is returned.
10710 -----------------------
10711 -- Parent_Is_Boolean --
10712 -----------------------
10715 begin
10718 | N_Op_Boolean
10719 | N_Short_Circuit
10723 -- Local variables
10727 -- Start of processing for Resolve_Op_Not
10729 begin
10730 -- Predefined operations on scalar types yield the base type. On the
10731 -- other hand, logical operations on arrays yield the type of the
10732 -- arguments (and the context).
10736 else
10740 -- Straightforward case of incorrect arguments
10747 -- Special case of probable missing parens
10751 Error_Msg_N
10754 else
10755 Error_Msg_N
10762 -- OK resolution of NOT
10764 else
10765 -- Warn if non-boolean types involved. This is a case like not a < b
10766 -- where a and b are modular, where we will get (not a) < b and most
10767 -- likely not (a < b) was intended.
10769 if Warn_On_Questionable_Missing_Parens
10771 and then Parent_Is_Boolean
10772 then
10776 -- Warn on double negation if checking redundant constructs
10778 if Warn_On_Redundant_Constructs
10783 then
10787 -- Complete resolution and evaluation of NOT
10797 -----------------------------
10798 -- Resolve_Operator_Symbol --
10799 -----------------------------
10801 -- Nothing to be done, all resolved already
10807 begin
10811 ----------------------------------
10812 -- Resolve_Qualified_Expression --
10813 ----------------------------------
10821 begin
10825 -- A qualified expression requires an exact match of the type, class-
10826 -- wide matching is not allowed. However, if the qualifying type is
10827 -- specific and the expression has a class-wide type, it may still be
10828 -- okay, since it can be the result of the expansion of a call to a
10829 -- dispatching function, so we also have to check class-wideness of the
10830 -- type of the expression's original node.
10833 or else
10837 then
10841 -- If the target type is unconstrained, then we reset the type of the
10842 -- result from the type of the expression. For other cases, the actual
10843 -- subtype of the expression is the target type. But we avoid doing it
10844 -- for an allocator since this is not needed and might be problematic.
10849 then
10856 -- If we still have a qualified expression after the static evaluation,
10857 -- then apply a scalar range check if needed. The reason that we do this
10858 -- after the Eval call is that otherwise, the application of the range
10859 -- check may convert an illegal static expression and result in warning
10860 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
10864 then
10868 -- AI12-0100: Once the qualified expression is resolved, check whether
10869 -- operand satisfies a static predicate of the target subtype, if any.
10870 -- In the static expression case, a predicate check failure is an error.
10873 Check_Expression_Against_Static_Predicate
10878 ------------------------------
10879 -- Resolve_Raise_Expression --
10880 ------------------------------
10883 begin
10888 else
10891 -- Apply check for required parentheses in the enclosing
10892 -- context of raise_expressions (RM 11.3 (2)), including default
10893 -- expressions in contexts that can include aspect specifications,
10894 -- and ancestor parts of extension aggregates.
10896 declare
10900 begin
10903 loop
10910 then
10917 if not Parentheses_Found
10919 and then
10921 | N_Floating_Point_Definition
10922 | N_Ordinary_Fixed_Point_Definition
10923 | N_Decimal_Fixed_Point_Definition
10924 | N_Extension_Aggregate
10925 | N_Discriminant_Specification
10926 | N_Parameter_Specification
10927 | N_Formal_Object_Declaration)
10930 and then
10932 then
10933 Error_Msg_N
10935 N);
10941 -------------------
10942 -- Resolve_Range --
10943 -------------------
10950 -- Returns True if N is of the form X'First .. X'Last where X is the
10951 -- same entity for both attributes.
10953 --------------------
10954 -- First_Last_Ref --
10955 --------------------
10961 begin
10966 then
10967 declare
10970 begin
10980 -- Start of processing for Resolve_Range
10982 begin
10988 -- Reanalyze the lower bound after both bounds have been analyzed, so
10989 -- that the range is known to be static or not by now. This may trigger
10990 -- more compile-time evaluation, which is useful for static analysis
10991 -- with GNATprove. This is not needed for compilation or static analysis
10992 -- with CodePeer, as full expansion does that evaluation then.
10999 -- Check for inappropriate range on unordered enumeration type
11003 -- Exclude X'First .. X'Last if X is the same entity for both
11005 and then not First_Last_Ref
11006 then
11008 Error_Msg_NE
11015 -- We have to check the bounds for being within the base range as
11016 -- required for a non-static context. Normally this is automatic and
11017 -- done as part of evaluating expressions, but the N_Range node is an
11018 -- exception, since in GNAT we consider this node to be a subexpression,
11019 -- even though in Ada it is not. The circuit in Sem_Eval could check for
11020 -- this, but that would put the test on the main evaluation path for
11021 -- expressions.
11026 -- Check for an ambiguous range over character literals. This will
11027 -- happen with a membership test involving only literals.
11035 -- If bounds are static, constant-fold them, so size computations are
11036 -- identical between front-end and back-end. Do not perform this
11037 -- transformation while analyzing generic units, as type information
11038 -- would be lost when reanalyzing the constant node in the instance.
11050 -- If we have a compile-time-known null range, we warn, because that is
11051 -- likely to be a mistake. (Dynamic null ranges make sense, but often
11052 -- compile-time-known ones do not.) Warn only if this is in a subtype
11053 -- declaration. We do this here, rather than while analyzing a subtype
11054 -- declaration, in case we decide to expand the cases. We do not want to
11055 -- warn in all cases, because some are idiomatic, such as an empty
11056 -- aggregate (1 .. 0 => <>).
11058 -- We don't warn in generics or their instances, because there might be
11059 -- some instances where the range is null, and some where it is not,
11060 -- which would lead to false alarms.
11064 and then Compile_Time_Compare
11070 then
11075 --------------------------
11076 -- Resolve_Real_Literal --
11077 --------------------------
11082 begin
11083 -- Special processing for fixed-point literals to make sure that the
11084 -- value is an exact multiple of the small where this is required. We
11085 -- skip this for the universal real case, and also for generic types.
11091 then
11092 -- We must freeze the base type to get the proper value of the small
11098 declare
11105 begin
11106 -- Case of literal is not an exact multiple of the Small
11110 -- For a source program literal for a decimal fixed-point type,
11111 -- this is statically illegal (RM 4.9(36)).
11116 then
11120 -- Generate a warning if literal from source
11123 and then Warn_On_Bad_Fixed_Value
11124 then
11125 Error_Msg_N
11127 N);
11130 -- Replace literal by a value that is the exact representation
11131 -- of a value of the type, i.e. a multiple of the small value,
11132 -- by truncation, since Machine_Rounds is false for all GNAT
11133 -- fixed-point types (RM 4.9(38)).
11143 -- In all cases, set the corresponding integer field
11149 -- Now replace the actual type by the expected type as usual
11155 -----------------------
11156 -- Resolve_Reference --
11157 -----------------------
11162 begin
11163 -- Replace general access with specific type
11171 -- If we are taking the reference of a volatile entity, then treat it as
11172 -- a potential modification of this entity. This is too conservative,
11173 -- but necessary because remove side effects can cause transformations
11174 -- of normal assignments into reference sequences that otherwise fail to
11175 -- notice the modification.
11182 --------------------------------
11183 -- Resolve_Selected_Component --
11184 --------------------------------
11199 -- Check whether this is the initialization of a component within an
11200 -- init proc (by assignment or call to another init proc). If true,
11201 -- there is no need for a discriminant check.
11203 --------------------
11204 -- Init_Component --
11205 --------------------
11208 begin
11209 return Inside_Init_Proc
11215 -- Start of processing for Resolve_Selected_Component
11217 begin
11220 -- Use the context type to select the prefix that has a selector
11221 -- of the correct name and type.
11229 else
11233 -- Locate selected component. For a private prefix the selector
11234 -- can denote a discriminant.
11238 -- The visible components of a class-wide type are those of
11239 -- the root type.
11249 then
11256 else
11260 Error_Msg_N
11265 else
11268 -- There may be an implicit dereference. Retrieve
11269 -- designated record type.
11273 else
11279 -- Resolution chooses the new interpretation.
11280 -- Find the component with the right name.
11285 loop
11302 -- There must be a legal interpretation at this point
11307 -- In general the expected type is the type of the context, not the
11308 -- type of the candidate selected component.
11313 -- The type of the context and that of the component are
11314 -- compatible and in general identical, but if they are anonymous
11315 -- access-to-subprogram types, the relevant type is that of the
11316 -- component. This matters in Unnest_Subprograms mode, where the
11317 -- relevant context is the one in which the type is declared, not
11318 -- the point of use. This determines what activation record to use.
11323 -- When the type of the component is an access to a class-wide type
11324 -- the relevant type is that of the component (since in such case we
11325 -- may need to generate implicit type conversions or dispatching
11326 -- calls).
11331 then
11335 else
11336 -- Resolve prefix with its type
11341 -- Generate cross-reference. We needed to wait until full overloading
11342 -- resolution was complete to do this, since otherwise we can't tell if
11343 -- we are an lvalue or not.
11347 else
11351 -- If the prefix's type is an access type, get to the real record type.
11352 -- Note: we do not apply an access check because an explicit dereference
11353 -- will be introduced later, and the check will happen there.
11359 else
11363 -- Set flag for expander if discriminant check required on a component
11364 -- appearing within a variant.
11370 and then
11373 and then not Init_Component
11374 then
11382 -- If the prefix is a record conversion, this may be a renamed
11383 -- discriminant whose bounds differ from those of the original
11384 -- one, so we must ensure that a range check is performed.
11389 then
11393 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11399 -- If the record type is atomic and the component is not, then this
11400 -- is worth a warning before Ada 2022, since we have a situation
11401 -- where the access to the component may cause extra read/writes of
11402 -- the atomic object, or partial word accesses, both of which may be
11403 -- unexpected.
11409 then
11410 Error_Msg_N
11413 Error_Msg_N
11423 -------------------
11424 -- Resolve_Shift --
11425 -------------------
11432 begin
11433 -- We do the resolution using the base type, because intermediate values
11434 -- in expressions always are of the base type, not a subtype of it.
11447 ---------------------------
11448 -- Resolve_Short_Circuit --
11449 ---------------------------
11456 begin
11457 -- Ensure all actions associated with the left operand (e.g.
11458 -- finalization of transient objects) are fully evaluated locally within
11459 -- an expression with actions. This is particularly helpful for coverage
11460 -- analysis. However this should not happen in generics or if option
11461 -- Minimize_Expression_With_Actions is set.
11464 declare
11466 begin
11474 -- Set Comes_From_Source on L to preserve warnings for unset
11475 -- reference.
11484 -- Check for issuing warning for always False assert/check, this happens
11485 -- when assertions are turned off, in which case the pragma Assert/Check
11486 -- was transformed into:
11488 -- if False and then <condition> then ...
11490 -- and we detect this pattern
11492 if Warn_On_Assertion_Failure
11499 then
11500 declare
11503 begin
11504 -- Special handling of Asssert pragma
11508 then
11509 declare
11511 Original_Node
11512 (Expression
11515 begin
11516 -- Don't warn if original condition is explicit False,
11517 -- since obviously the failure is expected in this case.
11521 then
11524 -- Issue warning. We do not want the deletion of the
11525 -- IF/AND-THEN to take this message with it. We achieve this
11526 -- by making sure that the expanded code points to the Sloc
11527 -- of the expression, not the original pragma.
11529 else
11530 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11531 -- The source location of the expression is not usually
11532 -- the best choice here. For example, it gets located on
11533 -- the last AND keyword in a chain of boolean expressiond
11534 -- AND'ed together. It is best to put the message on the
11535 -- first character of the assertion, which is the effect
11536 -- of the First_Node call here.
11538 Error_Msg_F
11540 Expression
11545 -- Similar processing for Check pragma
11549 then
11550 -- Don't want to warn if original condition is explicit False
11552 declare
11554 Original_Node
11555 (Expression
11557 begin
11560 then
11563 -- Post warning
11565 else
11566 -- Again use Error_Msg_F rather than Error_Msg_N, see
11567 -- comment above for an explanation of why we do this.
11569 Error_Msg_F
11571 Expression
11579 -- Continue with processing of short circuit
11588 -------------------
11589 -- Resolve_Slice --
11590 -------------------
11599 begin
11602 -- Use the context type to select the prefix that yields the correct
11603 -- array type.
11605 declare
11611 begin
11619 then
11627 else
11632 else
11643 else
11649 -- If the prefix's type is an access type, get to the real array type.
11650 -- Note: we do not apply an access check because an explicit dereference
11651 -- will be introduced later, and the check will happen there.
11656 -- If the prefix is an access to an unconstrained array, we must use
11657 -- the actual subtype of the object to perform the index checks. The
11658 -- object denoted by the prefix is implicit in the node, so we build
11659 -- an explicit representation for it in order to compute the actual
11660 -- subtype.
11665 declare
11669 begin
11676 -- In CodePeer mode the attribute Image is not expanded, so when it
11677 -- acts as a prefix of a slice, we handle it like a call to function
11678 -- returning an unconstrained string. Same for the Wide variants of
11679 -- attribute Image.
11688 | Name_Wide_Image
11689 | Name_Wide_Wide_Image)
11690 then
11693 -- If the name is a selected component that depends on discriminants,
11694 -- build an actual subtype for it. This can happen only when the name
11695 -- itself is overloaded; otherwise the actual subtype is created when
11696 -- the selected component is analyzed.
11699 and then Full_Analysis
11701 then
11702 declare
11705 begin
11710 -- Maybe this should just be "else", instead of checking for the
11711 -- specific case of slice??? This is needed for the case where the
11712 -- prefix is an Image attribute, which gets expanded to a slice, and so
11713 -- has a constrained subtype which we want to use for the slice range
11714 -- check applied below (the range check won't get done if the
11715 -- unconstrained subtype of the 'Image is used).
11721 -- Obtain the type of the array index
11725 else
11729 -- If name was overloaded, set slice type correctly now
11733 -- Handle the generation of a range check that compares the array index
11734 -- against the discrete_range. The check is not applied to internally
11735 -- built nodes associated with the expansion of dispatch tables. Check
11736 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11737 -- the unit.
11739 if Tagged_Type_Expansion
11745 then
11748 -- The discrete_range is specified by a subtype name. Create an
11749 -- equivalent range attribute, apply checks to this attribute, but
11750 -- insert them into the range expression of the slice itself.
11753 Dexpr :=
11754 Make_Attribute_Reference
11756 Prefix =>
11765 -- The discrete_range is a regular range (or a range attribute, which
11766 -- will be resolved into a regular range). Resolve the bounds and remove
11767 -- their side effects.
11769 else
11786 -- Check bad use of type with predicates
11788 declare
11791 begin
11794 then
11796 else
11801 Bad_Predicated_Subtype_Use
11806 -- Otherwise here is where we check suspicious indexes
11818 ----------------------------
11819 -- Resolve_String_Literal --
11820 ----------------------------
11831 begin
11832 -- For a string appearing in a concatenation, defer creation of the
11833 -- string_literal_subtype until the end of the resolution of the
11834 -- concatenation, because the literal may be constant-folded away. This
11835 -- is a useful optimization for long concatenation expressions.
11837 -- If the string is an aggregate built for a single character (which
11838 -- happens in a non-static context) or a is null string to which special
11839 -- checks may apply, we build the subtype. Wide strings must also get a
11840 -- string subtype if they come from a one character aggregate. Strings
11841 -- generated by attributes might be static, but it is often hard to
11842 -- determine whether the enclosing context is static, so we generate
11843 -- subtypes for them as well, thus losing some rarer optimizations ???
11844 -- Same for strings that come from a static conversion.
11846 Need_Check :=
11855 -- If the resolving type is itself a string literal subtype, we can just
11856 -- reuse it, since there is no point in creating another.
11862 and then not Need_Check
11864 | N_Attribute_Reference
11865 | N_Qualified_Expression
11866 | N_Type_Conversion
11867 then
11870 -- Do not generate a string literal subtype for the default expression
11871 -- of a formal parameter in GNATprove mode. This is because the string
11872 -- subtype is associated with the freezing actions of the subprogram,
11873 -- however freezing is disabled in GNATprove mode and as a result the
11874 -- subtype is unavailable.
11876 elsif GNATprove_Mode
11878 then
11881 -- Otherwise we must create a string literal subtype. Note that the
11882 -- whole idea of string literal subtypes is simply to avoid the need
11883 -- for building a full fledged array subtype for each literal.
11885 else
11891 or else Need_Check
11892 then
11899 then
11905 -- The validity of a null string has been checked in the call to
11906 -- Eval_String_Literal.
11911 -- Always accept string literal with component type Any_Character, which
11912 -- occurs in error situations and in comparisons of literals, both of
11913 -- which should accept all literals.
11918 -- If the type is bit-packed, then we always transform the string
11919 -- literal into a full fledged aggregate.
11924 -- Deal with cases of Wide_Wide_String, Wide_String, and String
11926 else
11927 -- For Standard.Wide_Wide_String, or any other type whose component
11928 -- type is Standard.Wide_Wide_Character, we know that all the
11929 -- characters in the string must be acceptable, since the parser
11930 -- accepted the characters as valid character literals.
11935 -- For the case of Standard.String, or any other type whose component
11936 -- type is Standard.Character, we must make sure that there are no
11937 -- wide characters in the string, i.e. that it is entirely composed
11938 -- of characters in range of type Character.
11940 -- If the string literal is the result of a static concatenation, the
11941 -- test has already been performed on the components, and need not be
11942 -- repeated.
11946 then
11950 -- If we are out of range, post error. This is one of the
11951 -- very few places that we place the flag in the middle of
11952 -- a token, right under the offending wide character. Not
11953 -- quite clear if this is right wrt wide character encoding
11954 -- sequences, but it's only an error message.
11956 Error_Msg
11963 -- For the case of Standard.Wide_String, or any other type whose
11964 -- component type is Standard.Wide_Character, we must make sure that
11965 -- there are no wide characters in the string, i.e. that it is
11966 -- entirely composed of characters in range of type Wide_Character.
11968 -- If the string literal is the result of a static concatenation,
11969 -- the test has already been performed on the components, and need
11970 -- not be repeated.
11974 then
11978 -- If we are out of range, post error. This is one of the
11979 -- very few places that we place the flag in the middle of
11980 -- a token, right under the offending wide character.
11982 -- This is not quite right, because characters in general
11983 -- will take more than one character position ???
11985 Error_Msg
11992 -- If the root type is not a standard character, then we will convert
11993 -- the string into an aggregate and will let the aggregate code do
11994 -- the checking. Standard Wide_Wide_Character is also OK here.
11996 else
12000 -- See if the component type of the array corresponding to the string
12001 -- has compile time known bounds. If yes we can directly check
12002 -- whether the evaluation of the string will raise constraint error.
12003 -- Otherwise we need to transform the string literal into the
12004 -- corresponding character aggregate and let the aggregate code do
12005 -- the checking. We use the same transformation if the component
12006 -- type has a static predicate, which will be applied to each
12007 -- character when the aggregate is resolved.
12011 -- Check for the case of full range, where we are definitely OK
12017 -- Here the range is not the complete base type range, so check
12019 declare
12027 begin
12030 then
12036 then
12037 Apply_Compile_Time_Constraint_Error
12039 CE_Range_Check_Failed,
12052 -- If we got here we meed to transform the string literal into the
12053 -- equivalent qualified positional array aggregate. This is rather
12054 -- heavy artillery for this situation, but it is hard work to avoid.
12056 declare
12061 begin
12062 -- Build the character literals, we give them source locations that
12063 -- correspond to the string positions, which is a bit tricky given
12064 -- the possible presence of wide character escape sequences.
12078 -- Should we have a call to Skip_Wide here ???
12080 -- ??? else
12081 -- Skip_Wide (P);
12089 Expression =>
12096 -------------------------
12097 -- Resolve_Target_Name --
12098 -------------------------
12101 begin
12105 -----------------------------
12106 -- Resolve_Type_Conversion --
12107 -----------------------------
12119 -- Set to False to suppress cases where we want to suppress the test
12120 -- for redundancy to avoid possible false positives on this warning.
12122 begin
12123 if not Conv_OK
12125 then
12129 -- If the Operand Etype is Universal_Fixed, then the conversion is
12130 -- never redundant. We need this check because by the time we have
12131 -- finished the rather complex transformation, the conversion looks
12132 -- redundant when it is not.
12137 -- If the operand is marked as Any_Fixed, then special processing is
12138 -- required. This is also a case where we suppress the test for a
12139 -- redundant conversion, since most certainly it is not redundant.
12144 -- Mixed-mode operation involving a literal. Context must be a fixed
12145 -- type which is applied to the literal subsequently.
12147 -- Multiplication and division involving two fixed type operands must
12148 -- yield a universal real because the result is computed in arbitrary
12149 -- precision.
12155 then
12161 or else
12163 then
12164 -- Return if expression is ambiguous
12169 -- If nothing else, the available fixed type is Duration
12171 else
12175 -- Resolve the real operand with largest available precision
12179 else
12185 -- If the operand is a literal (it could be a non-static and
12186 -- illegal exponentiation) check whether the use of Duration
12187 -- is potentially inaccurate.
12192 then
12193 Error_Msg_N
12196 Error_Msg_N
12203 then
12206 else
12217 -- Note: we do the Eval_Type_Conversion call before applying the
12218 -- required checks for a subtype conversion. This is important, since
12219 -- both are prepared under certain circumstances to change the type
12220 -- conversion to a constraint error node, but in the case of
12221 -- Eval_Type_Conversion this may reflect an illegality in the static
12222 -- case, and we would miss the illegality (getting only a warning
12223 -- message), if we applied the type conversion checks first.
12227 -- Even when evaluation is not possible, we may be able to simplify the
12228 -- conversion or its expression. This needs to be done before applying
12229 -- checks, since otherwise the checks may use the original expression
12230 -- and defeat the simplifications. This is specifically the case for
12231 -- elimination of the floating-point Truncation attribute in
12232 -- float-to-int conversions.
12236 -- If after evaluation we still have a type conversion, then we may need
12237 -- to apply checks required for a subtype conversion. But skip them if
12238 -- universal fixed operands are involved, since range checks are handled
12239 -- separately for these cases, after the expansion done by Exp_Fixd.
12245 then
12249 -- Issue warning for conversion of simple object to its own type. We
12250 -- have to test the original nodes, since they may have been rewritten
12251 -- by various optimizations.
12255 -- Here we test for a redundant conversion if the warning mode is
12256 -- active (and was not locally reset), and we have a type conversion
12257 -- from source not appearing in a generic instance.
12259 if Test_Redundant
12262 and then not In_Instance
12263 then
12267 -- If the node is part of a larger expression, the Target_Type
12268 -- may not be the original type of the node if the context is a
12269 -- condition. Recover original type to see if conversion is needed.
12273 then
12277 -- If we have an entity name, then give the warning if the entity
12278 -- is the right type, or if it is a loop parameter covered by the
12279 -- original type (that's needed because loop parameters have an
12280 -- odd subtype coming from the bounds).
12284 and then
12286 or else
12290 -- If not an entity, then type of expression must match
12293 then
12294 -- One more check, do not give warning if the analyzed conversion
12295 -- has an expression with non-static bounds, and the bounds of the
12296 -- target are static. This avoids junk warnings in cases where the
12297 -- conversion is necessary to establish staticness, for example in
12298 -- a case statement.
12302 then
12305 -- Never give a warning if the operand is a conditional expression
12306 -- because RM 4.5.7(10/3) forces its type to be the target type.
12311 -- Finally, if this type conversion occurs in a context requiring
12312 -- a prefix, and the expression is a qualified expression then the
12313 -- type conversion is not redundant, since a qualified expression
12314 -- is not a prefix, whereas a type conversion is. For example, "X
12315 -- := T'(Funx(...)).Y;" is illegal because a selected component
12316 -- requires a prefix, but a type conversion makes it legal: "X :=
12317 -- T(T'(Funx(...))).Y;"
12319 -- In Ada 2012, a qualified expression is a name, so this idiom is
12320 -- no longer needed, but we still suppress the warning because it
12321 -- seems unfriendly for warnings to pop up when you switch to the
12322 -- newer language version.
12326 | N_Indexed_Component
12327 | N_Selected_Component
12328 | N_Slice
12329 | N_Explicit_Dereference
12330 then
12333 -- Never warn on conversion to Long_Long_Integer'Base since
12334 -- that is most likely an artifact of the extended overflow
12335 -- checking and comes from complex expanded code.
12340 -- Here we give the redundant conversion warning. If it is an
12341 -- entity, give the name of the entity in the message. If not,
12342 -- just mention the expression.
12344 else
12347 Error_Msg_NE -- CODEFIX
12350 else
12351 Error_Msg_NE
12359 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12360 -- No need to perform any interface conversion if the type of the
12361 -- expression coincides with the target type.
12364 and then Expander_Active
12366 then
12367 declare
12371 begin
12372 -- If the type of the operand is a limited view, use nonlimited
12373 -- view when available. If it is a class-wide type, recover the
12374 -- class-wide type of the nonlimited view.
12378 then
12383 -- It seems that Non_Limited_View should also be applied for
12384 -- Target when it has a limited view, but that leads to missing
12385 -- error checks on interface conversions further below. ???
12390 -- If the type of the operand is a limited view, use nonlimited
12391 -- view when available. If it is a class-wide type, recover the
12392 -- class-wide type of the nonlimited view.
12396 then
12404 -- If the target type is a limited view, use nonlimited view
12405 -- when available.
12409 then
12417 -- Conversion from interface type
12419 -- It seems that it would be better for the error checks below
12420 -- to be performed as part of Validate_Conversion (and maybe some
12421 -- of the error checks above could be moved as well?). ???
12425 -- Ada 2005 (AI-217): Handle entities from limited views
12429 Error_Msg_NE -- CODEFIX
12432 Error_Msg_N
12434 N);
12437 and then not
12440 then
12442 Error_Msg_NE -- CODEFIX
12445 Error_Msg_N
12447 N);
12449 else
12453 -- Conversion to interface type
12461 -- Ada 2012: Once the type conversion is resolved, check whether the
12462 -- operand satisfies a static predicate of the target subtype, if any.
12463 -- In the static expression case, a predicate check failure is an error.
12466 Check_Expression_Against_Static_Predicate
12470 -- If at this stage we have a fixed to integer conversion, make sure the
12471 -- Do_Range_Check flag is set, because such conversions in general need
12472 -- a range check. We only need this if expansion is off, see above why.
12475 and then not Expander_Active
12480 then
12484 -- Generating C code a type conversion of an access to constrained
12485 -- array type to access to unconstrained array type involves building
12486 -- a fat pointer which in general cannot be generated on the fly. We
12487 -- remove side effects in order to store the result of the conversion
12488 -- into a temporary.
12490 if Modify_Tree_For_C
12497 then
12502 ----------------------
12503 -- Resolve_Unary_Op --
12504 ----------------------
12513 begin
12514 -- Deal with intrinsic unary operators
12520 then
12525 -- Deal with universal cases
12534 -- Generate warning for negative literal of a modular type, unless it is
12535 -- enclosed directly in a type qualification or a type conversion, as it
12536 -- is likely not what the user intended. We don't issue the warning for
12537 -- the common use of -1 to denote OxFFFF_FFFF...
12539 if Warn_On_Suspicious_Modulus_Value
12544 | N_Type_Conversion
12546 then
12547 Error_Msg_N
12552 Error_Msg_N
12556 -- Generate warning for expressions like abs (x mod 2)
12558 if Warn_On_Redundant_Constructs
12560 then
12564 Error_Msg_N -- CODEFIX
12569 -- Deal with reference generation
12576 -- Set overflow checking bit. Much cleverer code needed here eventually
12577 -- and perhaps the Resolve routines should be separated for the various
12578 -- arithmetic operations, since they will need different processing ???
12586 -- Generate warning for expressions like -5 mod 3 for integers. No need
12587 -- to worry in the floating-point case, since parens do not affect the
12588 -- result so there is no point in giving in a warning.
12590 declare
12599 begin
12600 if Warn_On_Questionable_Missing_Parens
12604 then
12607 -- We are looking for cases where the right operand is not
12608 -- parenthesized, and is a binary operator, multiply, divide, or
12609 -- mod. These are the cases where the grouping can affect results.
12613 then
12614 -- For mod, we always give the warning, since the value is
12615 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12616 -- -(5 mod 315)). But for the other cases, the only concern is
12617 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12618 -- overflows, but (-2) * 64 does not). So we try to give the
12619 -- message only when overflow is possible.
12623 then
12628 else
12634 else
12638 -- Note that the test below is deliberately excluding the
12639 -- largest negative number, since that is a potentially
12640 -- troublesome case (e.g. -2 * x, where the result is the
12641 -- largest negative integer has an overflow with 2 * x).
12648 -- For the multiplication case, the only case we have to worry
12649 -- about is when (-a)*b is exactly the largest negative number
12650 -- so that -(a*b) can cause overflow. This can only happen if
12651 -- a is a power of 2, and more generally if any operand is a
12652 -- constant that is not a power of 2, then the parentheses
12653 -- cannot affect whether overflow occurs. We only bother to
12654 -- test the left most operand
12656 -- Loop looking at left operands for one that has known value
12663 -- Operand value of 0 or 1 skips warning
12668 -- Otherwise check power of 2, if power of 2, warn, if
12669 -- anything else, skip warning.
12671 else
12675 else
12684 -- Keep looking at left operands
12689 -- For rem or "/" we can only have a problematic situation
12690 -- if the divisor has a value of minus one or one. Otherwise
12691 -- overflow is impossible (divisor > 1) or we have a case of
12692 -- division by zero in any case.
12697 then
12701 -- If we fall through warning should be issued
12703 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12705 Error_Msg_N
12712 ----------------------------------
12713 -- Resolve_Unchecked_Expression --
12714 ----------------------------------
12716 procedure Resolve_Unchecked_Expression
12719 is
12720 begin
12725 ---------------------------------------
12726 -- Resolve_Unchecked_Type_Conversion --
12727 ---------------------------------------
12729 procedure Resolve_Unchecked_Type_Conversion
12732 is
12738 begin
12739 -- Resolve operand using its own type
12743 -- If the expression is a conversion to universal integer of an
12744 -- an expression with an integer type, then we can eliminate the
12745 -- intermediate conversion to universal integer.
12750 then
12755 -- In an inlined context, the unchecked conversion may be applied
12756 -- to a literal, in which case its type is the type of the context.
12757 -- (In other contexts conversions cannot apply to literals).
12759 if In_Inlined_Body
12763 then
12771 ------------------------------
12772 -- Rewrite_Operator_As_Call --
12773 ------------------------------
12780 begin
12787 New_N :=
12798 ------------------------------
12799 -- Rewrite_Renamed_Operator --
12800 ------------------------------
12802 procedure Rewrite_Renamed_Operator
12806 is
12811 begin
12812 -- Do not perform this transformation within a pre/postcondition,
12813 -- because the expression will be reanalyzed, and the transformation
12814 -- might affect the visibility of the operator, e.g. in an instance.
12815 -- Note that fully analyzed and expanded pre/postconditions appear as
12816 -- pragma Check equivalents.
12822 -- Likewise when an expression function is being preanalyzed, since the
12823 -- expression will be reanalyzed as part of the generated body.
12826 declare
12828 begin
12831 N_Expression_Function
12832 then
12848 -- Indicate that both the original entity and its renaming are
12849 -- referenced at this point.
12856 -- If the context type is private, add the appropriate conversions so
12857 -- that the operator is applied to the full view. This is done in the
12858 -- routines that resolve intrinsic operators.
12862 when N_Op_Add
12863 | N_Op_Divide
12864 | N_Op_Expon
12865 | N_Op_Mod
12866 | N_Op_Multiply
12867 | N_Op_Rem
12868 | N_Op_Subtract
12869 =>
12872 when N_Op_Abs
12873 | N_Op_Minus
12874 | N_Op_Plus
12875 =>
12884 -----------------------
12885 -- Set_Slice_Subtype --
12886 -----------------------
12888 -- Build an implicit subtype declaration to represent the type delivered by
12889 -- the slice. This is an abbreviated version of an array subtype. We define
12890 -- an index subtype for the slice, using either the subtype name or the
12891 -- discrete range of the slice. To be consistent with index usage elsewhere
12892 -- we create a list header to hold the single index. This list is not
12893 -- otherwise attached to the syntax tree.
12904 begin
12910 else
12911 -- We force the evaluation of a range. This is definitely needed in
12912 -- the renamed case, and seems safer to do unconditionally. Note in
12913 -- any case that since we will create and insert an Itype referring
12914 -- to this range, we must make sure any side effect removal actions
12915 -- are inserted before the Itype definition.
12921 -- If the discrete range is given by a subtype indication, the
12922 -- type of the slice is the base of the subtype mark.
12925 declare
12927 begin
12936 -- Take a new copy of Drange (where bounds have been rewritten to
12937 -- reference side-effect-free names). Using a separate tree ensures
12938 -- that further expansion (e.g. while rewriting a slice assignment
12939 -- into a FOR loop) does not attempt to remove side effects on the
12940 -- bounds again (which would cause the bounds in the index subtype
12941 -- definition to refer to temporaries before they are defined) (the
12942 -- reason is that some names are considered side effect free here
12943 -- for the subtype, but not in the context of a loop iteration
12944 -- scheme).
12966 -- The Etype of the existing Slice node is reset to this slice subtype.
12967 -- Its bounds are obtained from its first index.
12971 -- For bit-packed slice subtypes, freeze immediately (except in the case
12972 -- of being in a "spec expression" where we never freeze when we first
12973 -- see the expression).
12978 -- For all other cases insert an itype reference in the slice's actions
12979 -- so that the itype is frozen at the proper place in the tree (i.e. at
12980 -- the point where actions for the slice are analyzed). Note that this
12981 -- is different from freezing the itype immediately, which might be
12982 -- premature (e.g. if the slice is within a transient scope). This needs
12983 -- to be done only if expansion is enabled.
12990 --------------------------------
12991 -- Set_String_Literal_Subtype --
12992 --------------------------------
13000 begin
13012 -- The low bound is set from the low bound of the corresponding index
13013 -- type. Note that we do not store the high bound in the string literal
13014 -- subtype, but it can be deduced if necessary from the length and the
13015 -- low bound.
13020 -- If the lower bound is not static we create a range for the string
13021 -- literal, using the index type and the known length of the literal.
13022 -- If the length is 1, then the upper bound is set to a mere copy of
13023 -- the lower bound; or else, if the index type is a signed integer,
13024 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
13025 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
13027 else
13028 declare
13038 begin
13043 High_Bound :=
13048 else
13049 High_Bound :=
13052 Prefix =>
13056 Left_Opnd =>
13059 Prefix =>
13061 Expressions =>
13063 Right_Opnd =>
13068 Set_String_Literal_Low_Bound
13071 else
13072 -- If the index type is an enumeration type, build bounds
13073 -- expression with attributes.
13075 Set_String_Literal_Low_Bound
13079 Prefix =>
13083 Analyze_And_Resolve
13086 -- Build bona fide subtype for the string, and wrap it in an
13087 -- unchecked conversion, because the back end expects the
13088 -- String_Literal_Subtype to have a static lower bound.
13090 Index_Subtype :=
13097 -- In this context, the Index_Type may already have a constraint,
13098 -- so use common base type on string subtype. The base type may
13099 -- be used when generating attributes of the string, for example
13100 -- in the context of a slice assignment.
13122 ------------------------------
13123 -- Simplify_Type_Conversion --
13124 ------------------------------
13127 begin
13129 declare
13134 begin
13135 -- Special processing if the conversion is the expression of a
13136 -- Rounding or Truncation attribute reference. In this case we
13137 -- replace:
13139 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
13141 -- by
13143 -- ityp (x)
13145 -- with the Float_Truncate flag set to False or True respectively,
13146 -- which is more efficient. We reuse Rounding for Machine_Rounding
13147 -- as System.Fat_Gen, which is a permissible behavior.
13150 and then
13156 | Name_Machine_Rounding
13157 | Name_Truncation
13158 then
13159 declare
13162 begin
13168 -- Special processing for the conversion of an integer literal to
13169 -- a dynamic type: we first convert the literal to the root type
13170 -- and then convert the result to the target type, the goal being
13171 -- to avoid doing range checks in universal integer.
13177 then
13181 -- If the expression is a conversion to universal integer of an
13182 -- an expression with an integer type, then we can eliminate the
13183 -- intermediate conversion to universal integer.
13188 then
13196 ------------------------------
13197 -- Try_User_Defined_Literal --
13198 ------------------------------
13200 function Try_User_Defined_Literal
13203 is
13204 begin
13206 | N_Op_Rem | N_Op_Subtract
13207 then
13209 -- Both operands must have the same type as the context.
13210 -- (ignoring for now fixed-point and exponentiation ops).
13218 if
13220 then
13225 else
13230 -- For other operators the context does not impose a type on
13231 -- the operands, but their types must match.
13235 and then
13236 Has_Applicable_User_Defined_Literal
13238 then
13244 and then
13245 Has_Applicable_User_Defined_Literal
13247 then
13250 else
13255 and then
13257 then
13266 -----------------------------
13267 -- Unique_Fixed_Point_Type --
13268 -----------------------------
13272 -- Give error messages for true ambiguity. Messages are posted on node
13273 -- N, and entities T1, T2 are the possible interpretations.
13275 -----------------------
13276 -- Fixed_Point_Error --
13277 -----------------------
13280 begin
13286 -- Local variables
13294 -- Start of processing for Unique_Fixed_Point_Type
13296 begin
13297 -- The operations on Duration are visible, so Duration is always a
13298 -- possible interpretation.
13302 -- Look for fixed-point types in enclosing scopes
13311 then
13315 else
13326 -- Look for visible fixed type declarations in the context
13337 then
13341 else
13356 else
13357 -- When the context is a type conversion, issue the warning on the
13358 -- expression of the conversion because it is the actual operation.
13362 else
13366 Error_Msg_NE
13373 ----------------------
13374 -- Valid_Conversion --
13375 ----------------------
13377 function Valid_Conversion
13382 is
13387 function Conversion_Check
13390 -- Little routine to post Msg if Valid is False, returns Valid value
13393 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13395 procedure Conversion_Error_NE
13399 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13402 -- Return True if expression is within an instance but is not in one of
13403 -- the actuals of the instantiation. Type conversions within an instance
13404 -- are not rechecked because type visibility may lead to spurious errors
13405 -- but conversions in an actual for a formal object must be checked.
13407 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13409 -- Implicit anonymous-to-named access type conversions are not allowed
13410 -- if the "statically deeper than" relationship does not apply to the
13411 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13412 -- We deal with most such cases elsewhere so that we can emit more
13413 -- specific error messages (e.g., if the operand is an access parameter
13414 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13415 -- here is where we catch the case where the operand is an access
13416 -- discriminant selected from a dereference of another such "bad"
13417 -- conversion argument.
13419 function Valid_Tagged_Conversion
13422 -- Specifically test for validity of tagged conversions
13425 -- Check index and component conformance, and accessibility levels if
13426 -- the component types are anonymous access types (Ada 2005).
13428 ----------------------
13429 -- Conversion_Check --
13430 ----------------------
13432 function Conversion_Check
13435 is
13436 begin
13437 if not Valid
13439 -- A generic unit has already been analyzed and we have verified
13440 -- that a particular conversion is OK in that context. Since the
13441 -- instance is reanalyzed without relying on the relationships
13442 -- established during the analysis of the generic, it is possible
13443 -- to end up with inconsistent views of private types. Do not emit
13444 -- the error message in such cases. The rest of the machinery in
13445 -- Valid_Conversion still ensures the proper compatibility of
13446 -- target and operand types.
13448 and then not In_Instance_Code
13449 then
13456 ------------------------
13457 -- Conversion_Error_N --
13458 ------------------------
13461 begin
13467 -------------------------
13468 -- Conversion_Error_NE --
13469 -------------------------
13471 procedure Conversion_Error_NE
13475 is
13476 begin
13482 ----------------------
13483 -- In_Instance_Code --
13484 ----------------------
13489 begin
13493 else
13497 -- The expression is part of an actual object if it appears in
13498 -- the generated object declaration in the instance.
13502 then
13505 else
13506 exit when
13515 -- Otherwise the expression appears within the instantiated unit
13521 --------------------------------------------------
13522 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13523 --------------------------------------------------
13525 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13527 is
13533 begin
13545 -- return False if Expr not of form <prefix>.all.Some_Component
13549 then
13550 -- conditional expressions, declare expressions ???
13557 -- The "statically deeper relationship" does not apply
13558 -- to generic formal access types, so a prefix of such
13559 -- a type is a "bad" prefix.
13564 -- The "statically deeper relationship" does apply to
13565 -- any other named access type.
13574 -- The "statically deeper relationship" applies to some
13575 -- anonymous access types and not to others. Return
13576 -- True for the cases where it does not apply. Also check
13577 -- recursively for the
13578 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13579 -- where the correct result depends on <prefix>.
13582 N_Procedure_Specification | -- access parameter
13583 N_Function_Specification | -- access parameter
13584 N_Object_Declaration -- saooaaat
13588 ----------------------------
13589 -- Valid_Array_Conversion --
13590 ----------------------------
13607 begin
13608 -- Error if wrong number of dimensions
13610 if
13612 then
13613 Conversion_Error_N
13617 -- Number of dimensions matches
13619 else
13620 -- Loop through indexes of the two arrays
13628 -- Error if index types are incompatible
13634 then
13635 Conversion_Error_N
13637 Operand);
13645 -- If component types have same base type, all set
13650 -- Here if base types of components are not the same. The only
13651 -- time this is allowed is if we have anonymous access types.
13653 -- The conversion of arrays of anonymous access types can lead
13654 -- to dangling pointers. AI-392 formalizes the accessibility
13655 -- checks that must be applied to such conversions to prevent
13656 -- out-of-scope references.
13659 E_Anonymous_Access_Type
13660 | E_Anonymous_Access_Subprogram_Type
13662 and then
13664 then
13667 then
13670 Conversion_Error_N
13680 -- Conversion not allowed because of accessibility levels
13682 else
13683 Conversion_Error_N
13689 else
13693 -- All other cases where component base types do not match
13695 else
13696 Conversion_Error_N
13698 Operand);
13702 -- Check that component subtypes statically match. For numeric
13703 -- types this means that both must be either constrained or
13704 -- unconstrained. For enumeration types the bounds must match.
13705 -- All of this is checked in Subtypes_Statically_Match.
13707 if not Subtypes_Statically_Match
13709 then
13710 Conversion_Error_N
13719 -----------------------------
13720 -- Valid_Tagged_Conversion --
13721 -----------------------------
13723 function Valid_Tagged_Conversion
13726 is
13727 begin
13728 -- Upward conversions are allowed (RM 4.6(22))
13732 then
13735 -- Downward conversion are allowed if the operand is class-wide
13736 -- (RM 4.6(23)).
13740 then
13745 then
13746 return
13750 -- Ada 2005 (AI-251): A conversion is valid if the operand and target
13751 -- types are both class-wide types and the specific type associated
13752 -- with at least one of them is an interface type (RM 4.6 (23.1/2));
13753 -- at run-time a check will verify the validity of this interface
13754 -- type conversion.
13760 then
13763 -- Report errors
13768 and then not Interface_Present_In_Ancestor
13771 then
13774 Conversion_Error_N
13782 and then not Interface_Present_In_Ancestor
13785 then
13788 Conversion_Error_N
13792 -- Search for interface types shared between the target type and
13793 -- the operand interface type to complete the text of the error
13794 -- since the source of this error is a missing type conversion
13795 -- to such interface type.
13798 declare
13805 begin
13807 Target_Ifaces_List);
13809 Operand_Ifaces_List);
13817 then
13818 Error_Msg_Name_1 :=
13823 Conversion_Error_N
13826 else
13827 Conversion_Error_N
13845 then
13846 Conversion_Error_N
13848 Conversion_Error_N
13854 then
13855 Conversion_Error_N
13860 else
13861 Conversion_Error_NE
13868 -- Start of processing for Valid_Conversion
13870 begin
13874 declare
13882 begin
13883 -- Remove procedure calls, which syntactically cannot appear in
13884 -- this context, but which cannot be removed by type checking,
13885 -- because the context does not impose a type.
13887 -- The node may be labelled overloaded, but still contain only one
13888 -- interpretation because others were discarded earlier. If this
13889 -- is the case, retain the single interpretation if legal.
13897 then
13898 -- More than one candidate interpretation is available
13906 -- When compiling for a system where Address is of a visible
13907 -- integer type, spurious ambiguities can be produced when
13908 -- arithmetic operations have a literal operand and return
13909 -- System.Address or a descendant of it. These ambiguities
13910 -- are usually resolved by the context, but for conversions
13911 -- there is no context type and the removal of the spurious
13912 -- operations must be done explicitly here.
13914 if not Address_Is_Private
13916 then
13941 Conversion_Error_N
13944 -- If the interpretation involves a standard operator, use
13945 -- the location of the type, which may be user-defined.
13949 else
13953 Conversion_Error_N -- CODEFIX
13958 else
13962 Conversion_Error_N -- CODEFIX
13974 -- Deal with conversion of integer type to address if the pragma
13975 -- Allow_Integer_Address is in effect. We convert the conversion to
13976 -- an unchecked conversion in this case and we are all done.
13984 -- If we are within a child unit, check whether the type of the
13985 -- expression has an ancestor in a parent unit, in which case it
13986 -- belongs to its derivation class even if the ancestor is private.
13987 -- See RM 7.3.1 (5.2/3).
13991 -- Numeric types
13995 -- A universal fixed expression can be converted to any numeric type
14000 -- Also no need to check when in an instance or inlined body, because
14001 -- the legality has been established when the template was analyzed.
14002 -- Furthermore, numeric conversions may occur where only a private
14003 -- view of the operand type is visible at the instantiation point.
14004 -- This results in a spurious error if we check that the operand type
14005 -- is a numeric type.
14007 -- Note: in a previous version of this unit, the following tests were
14008 -- applied only for generated code (Comes_From_Source set to False),
14009 -- but in fact the test is required for source code as well, since
14010 -- this situation can arise in source code.
14015 -- Otherwise we need the conversion check
14017 else
14018 return Conversion_Check
14020 or else
14026 -- Array types
14032 then
14033 Conversion_Error_N
14037 else
14041 -- Ada 2005 (AI-251): Internally generated conversions of access to
14042 -- interface types added to force the displacement of the pointer to
14043 -- reference the corresponding dispatch table.
14048 then
14051 -- Ada 2005 (AI-251): Anonymous access types where target references an
14052 -- interface type.
14056 E_General_Access_Type | E_Anonymous_Access_Type
14058 then
14059 -- Check the static accessibility rule of 4.6(17). Note that the
14060 -- check is not enforced when within an instance body, since the
14061 -- RM requires such cases to be caught at run time.
14063 -- If the operand is a rewriting of an allocator no check is needed
14064 -- because there are no accessibility issues.
14072 then
14073 -- In an instance, this is a run-time check, but one we know
14074 -- will fail, so generate an appropriate warning. The raise
14075 -- will be generated by Expand_N_Type_Conversion.
14079 Conversion_Error_N
14081 Operand);
14084 else
14085 Conversion_Error_N
14087 Operand);
14091 -- Special accessibility checks are needed in the case of access
14092 -- discriminants declared for a limited type.
14096 then
14097 -- When the operand is a selected access discriminant the check
14098 -- needs to be made against the level of the object denoted by
14099 -- the prefix of the selected name (Accessibility_Level handles
14100 -- checking the prefix of the operand for this case).
14103 and then Static_Accessibility_Level
14106 then
14107 -- In an instance, this is a run-time check, but one we know
14108 -- will fail, so generate an appropriate warning. The raise
14109 -- will be generated by Expand_N_Type_Conversion.
14113 Conversion_Error_N
14118 -- Real error if not in instance body
14120 else
14121 Conversion_Error_N
14128 -- The case of a reference to an access discriminant from
14129 -- within a limited type declaration (which will appear as
14130 -- a discriminal) is always illegal because the level of the
14131 -- discriminant is considered to be deeper than any (nameable)
14132 -- access type.
14136 and then
14139 then
14140 Conversion_Error_N
14142 Operand);
14150 -- General and anonymous access types
14153 E_General_Access_Type | E_Anonymous_Access_Type
14154 and then
14155 Conversion_Check
14157 and then
14159 E_Access_Subprogram_Type |
14160 E_Access_Protected_Subprogram_Type,
14162 then
14165 then
14166 Conversion_Error_N
14171 -- Check the static accessibility rule of 4.6(17). Note that the
14172 -- check is not enforced when within an instance body, since the RM
14173 -- requires such cases to be caught at run time.
14178 N_Object_Declaration
14179 then
14180 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
14181 -- conversions from an anonymous access type to a named general
14182 -- access type. Such conversions are not allowed in the case of
14183 -- access parameters and stand-alone objects of an anonymous
14184 -- access type. The implicit conversion case is recognized by
14185 -- testing that Comes_From_Source is False and that it's been
14186 -- rewritten. The Comes_From_Source test isn't sufficient because
14187 -- nodes in inlined calls to predefined library routines can have
14188 -- Comes_From_Source set to False. (Is there a better way to test
14189 -- for implicit conversions???).
14190 --
14191 -- Do not treat a rewritten 'Old attribute reference like other
14192 -- rewrite substitutions. This makes a difference, for example,
14193 -- in the case where we are generating the expansion of a
14194 -- membership test of the form
14195 -- Saooaaat'Old in Named_Access_Type
14196 -- because in this case Valid_Conversion needs to return True
14197 -- (otherwise the expansion will be False - see the call site
14198 -- in exp_ch4.adb).
14206 then
14209 -- When applying restriction No_Dynamic_Accessibility_Check,
14210 -- implicit conversions are allowed when the operand type is
14211 -- not deeper than the target type.
14216 then
14217 Conversion_Error_N
14221 -- Implicit conversions aren't allowed for objects of an
14222 -- anonymous access type, since such objects have nonstatic
14223 -- levels in Ada 2012.
14226 = N_Object_Declaration
14227 then
14228 Conversion_Error_N
14233 -- Implicit conversions aren't allowed for anonymous access
14234 -- parameters. We exclude anonymous access results as well
14235 -- as universal_access "=".
14239 N_Function_Specification |
14240 N_Procedure_Specification
14242 then
14243 Conversion_Error_N
14248 -- Detect access discriminant values that are illegal
14249 -- implicit anonymous-to-named access conversion operands.
14252 then
14253 Conversion_Error_N
14258 -- In other cases, the level of the operand's type must be
14259 -- statically less deep than that of the target type, else
14260 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
14264 then
14265 Conversion_Error_N
14272 -- Check if the operand is deeper than the target type, taking
14273 -- care to avoid the case where we are converting a result of a
14274 -- function returning an anonymous access type since the "master
14275 -- of the call" would be target type of the conversion unless
14276 -- the target type is anonymous access as well - see RM 3.10.2
14277 -- (10.3/3).
14279 -- Note that when the restriction No_Dynamic_Accessibility_Checks
14280 -- is in effect wei also want to proceed with the conversion check
14281 -- described above.
14286 /= N_Function_Specification
14290 -- Check we are not in a return value ???
14293 or else
14296 then
14297 -- In an instance, this is a run-time check, but one we know
14298 -- will fail, so generate an appropriate warning. The raise
14299 -- will be generated by Expand_N_Type_Conversion.
14303 Conversion_Error_N
14305 Operand);
14308 -- If not in an instance body, this is a real error
14310 else
14311 -- Avoid generation of spurious error message
14314 Conversion_Error_N
14316 Operand);
14322 -- Special accessibility checks are needed in the case of access
14323 -- discriminants declared for a limited type.
14327 then
14328 -- When the operand is a selected access discriminant the check
14329 -- needs to be made against the level of the object denoted by
14330 -- the prefix of the selected name (Accessibility_Level handles
14331 -- checking the prefix of the operand for this case).
14334 and then Static_Accessibility_Level
14337 then
14338 -- In an instance, this is a run-time check, but one we know
14339 -- will fail, so generate an appropriate warning. The raise
14340 -- will be generated by Expand_N_Type_Conversion.
14344 Conversion_Error_N
14349 -- If not in an instance body, this is a real error
14351 else
14352 Conversion_Error_N
14359 -- The case of a reference to an access discriminant from
14360 -- within a limited type declaration (which will appear as
14361 -- a discriminal) is always illegal because the level of the
14362 -- discriminant is considered to be deeper than any (nameable)
14363 -- access type.
14366 and then
14369 then
14370 Conversion_Error_N
14372 Operand);
14378 -- In the presence of limited_with clauses we have to use nonlimited
14379 -- views, if available.
14383 -- Helper function to handle limited views
14385 --------------------------
14386 -- Full_Designated_Type --
14387 --------------------------
14392 begin
14393 -- Handle the limited view of a type
14397 then
14399 else
14404 -- Local Declarations
14412 -- Start of processing for Check_Limited
14414 begin
14418 else
14420 Conversion_Error_NE
14425 -- Ada 2005 AI-384: legality rule is symmetric in both
14426 -- designated types. The conversion is legal (with possible
14427 -- constraint check) if either designated type is
14428 -- unconstrained.
14431 or else
14433 and then
14436 then
14437 -- Special case, if Value_Size has been used to make the
14438 -- sizes different, the conversion is not allowed even
14439 -- though the subtypes statically match.
14444 then
14445 Conversion_Error_NE
14448 Conversion_Error_NE
14453 -- Normal case where conversion is allowed
14455 else
14459 else
14460 Error_Msg_NE
14468 -- Access to subprogram types. If the operand is an access parameter,
14469 -- the type has a deeper accessibility that any master, and cannot be
14470 -- assigned. We must make an exception if the conversion is part of an
14471 -- assignment and the target is the return object of an extended return
14472 -- statement, because in that case the accessibility check takes place
14473 -- after the return.
14477 -- Note: this test of Opnd_Type is there to prevent entering this
14478 -- branch in the case of a remote access to subprogram type, which
14479 -- is internally represented as an E_Record_Type.
14482 then
14486 and then
14490 then
14491 Conversion_Error_N
14493 Operand);
14494 Conversion_Error_N
14497 Operand);
14499 Error_Msg_NE
14504 -- Check that the designated types are subtype conformant
14510 -- Check the static accessibility rule of 4.6(20)
14514 then
14515 Conversion_Error_N
14517 Operand);
14519 -- Check that if the operand type is declared in a generic body,
14520 -- then the target type must be declared within that same body
14521 -- (enforces last sentence of 4.6(20)).
14524 declare
14530 begin
14537 Conversion_Error_N
14544 -- Check that the strub modes are compatible.
14545 -- We wish to reject explicit conversions only for
14546 -- incompatible modes.
14548 return Conversion_Check
14549 (Compatible_Strub_Modes
14554 -- Remote access to subprogram types
14558 then
14559 -- It is valid to convert from one RAS type to another provided
14560 -- that their specification statically match.
14562 -- Note: at this point, remote access to subprogram types have been
14563 -- expanded to their E_Record_Type representation, and we need to
14564 -- go back to the original access type definition using the
14565 -- Corresponding_Remote_Type attribute in order to check that the
14566 -- designated profiles match.
14571 Check_Subtype_Conformant
14574 Old_Id =>
14576 Err_Loc =>
14577 N);
14579 -- Check that the strub modes are compatible.
14580 -- We wish to reject explicit conversions only for
14581 -- incompatible modes.
14583 return Conversion_Check
14584 (Compatible_Strub_Modes
14589 -- If it was legal in the generic, it's legal in the instance
14594 -- If both are tagged types, check legality of view conversions
14597 and then
14599 then
14602 -- Types derived from the same root type are convertible
14607 -- In an instance or an inlined body, there may be inconsistent views of
14608 -- the same type, or of types derived from a common root.
14611 and then
14614 then
14617 -- Special check for common access type error case
14621 then
14623 Conversion_Error_NE -- CODEFIX
14627 -- Here we have a real conversion error
14629 else
14630 -- Check for missing regular with_clause when only a limited view of
14631 -- target is available.
14634 Conversion_Error_NE
14637 Conversion_Error_NE
14642 and then In_Package_Body
14643 then
14644 Conversion_Error_NE
14646 Conversion_Error_NE
14650 else
14651 Conversion_Error_NE