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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) 1992-2022, 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 ------------------------------------------------------------------------------
94 -----------------------
95 -- Local Subprograms --
96 -----------------------
98 -- Second pass (top-down) type checking and overload resolution procedures
99 -- Typ is the type required by context. These procedures propagate the
100 -- type information recursively to the descendants of N. If the node is not
101 -- overloaded, its Etype is established in the first pass. If overloaded,
102 -- the Resolve routines set the correct type. For arithmetic operators, the
103 -- Etype is the base type of the context.
105 -- Note that Resolve_Attribute is separated off in Sem_Attr
107 function Has_Applicable_User_Defined_Literal
110 -- If N is a literal or a named number, check whether Typ
111 -- has a user-defined literal aspect that can apply to N.
112 -- If present, replace N with a call to the corresponding
113 -- function and return True.
116 -- Enforce the restrictions on the use of discriminants when constraining
117 -- a component of a discriminated type (record or concurrent type).
120 -- Given a node for an operator associated with type T, check that the
121 -- operator is visible. Operators all of whose operands are universal must
122 -- be checked for visibility during resolution because their type is not
123 -- determinable based on their operands.
125 procedure Check_Fully_Declared_Prefix
128 -- Check that the type of the prefix of a dereference is not incomplete
131 -- Given a call node, Call, which is known to occur immediately within the
132 -- subprogram being called, determines whether it is a detectable case of
133 -- an infinite recursion, and if so, outputs appropriate messages. Returns
134 -- True if an infinite recursion is detected, and False otherwise.
137 -- N is the node for a logical operator. If the operator is predefined, and
138 -- the root type of the operands is Standard.Boolean, then a check is made
139 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
140 -- the style check for Style_Check_Boolean_And_Or.
143 -- N is either an indexed component or a selected component. This function
144 -- returns true if the prefix denotes an atomic object that has an address
145 -- clause (the case in which we may want to issue a warning).
148 -- Determine whether E is an access type declared by an access declaration,
149 -- and not an (anonymous) allocator type.
152 -- Utility to check whether the entity for an operator is a predefined
153 -- operator, in which case the expression is left as an operator in the
154 -- tree (else it is rewritten into a call). An instance of an intrinsic
155 -- conversion operation may be given an operator name, but is not treated
156 -- like an operator. Note that an operator that is an imported back-end
157 -- builtin has convention Intrinsic, but is expected to be rewritten into
158 -- a call, so such an operator is not treated as predefined by this
159 -- predicate.
161 procedure Preanalyze_And_Resolve
165 -- Subsidiary of public versions of Preanalyze_And_Resolve.
168 -- If a default expression in entry call N depends on the discriminants
169 -- of the task, it must be replaced with a reference to the discriminant
170 -- of the task being called.
172 procedure Resolve_Op_Concat_Arg
177 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
178 -- concatenation operator. The operand is either of the array type or of
179 -- the component type. If the operand is an aggregate, and the component
180 -- type is composite, this is ambiguous if component type has aggregates.
183 -- Does the first part of the work of Resolve_Op_Concat
186 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
187 -- has been resolved. See Resolve_Op_Concat for details.
227 function Operator_Kind
230 -- Utility to map the name of an operator into the corresponding Node. Used
231 -- by other node rewriting procedures.
234 -- Resolve actuals of call, and add default expressions for missing ones.
235 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
236 -- called subprogram.
239 -- Called from Resolve_Call, when the prefix denotes an entry or element
240 -- of entry family. Actuals are resolved as for subprograms, and the node
241 -- is rebuilt as an entry call. Also called for protected operations. Typ
242 -- is the context type, which is used when the operation is a protected
243 -- function with no arguments, and the return value is indexed.
246 -- Called when P is the prefix of an indexed component, or of a selected
247 -- component, or of a slice. If P is of an access type, we unconditionally
248 -- rewrite it as an explicit dereference. This ensures that the expander
249 -- and the code generator have a fully explicit tree to work with.
252 -- A call to a user-defined intrinsic operator is rewritten as a call to
253 -- the corresponding predefined operator, with suitable conversions. Note
254 -- that this applies only for intrinsic operators that denote predefined
255 -- operators, not ones that are intrinsic imports of back-end builtins.
258 -- Ditto, for arithmetic unary operators
261 -- If an operator node resolves to a call to a user-defined operator,
262 -- rewrite the node as a function call.
264 procedure Make_Call_Into_Operator
268 -- Inverse transformation: if an operator is given in functional notation,
269 -- then after resolving the node, transform into an operator node, so that
270 -- operands are resolved properly. Recall that predefined operators do not
271 -- have a full signature and special resolution rules apply.
273 procedure Rewrite_Renamed_Operator
277 -- An operator can rename another, e.g. in an instantiation. In that
278 -- case, the proper operator node must be constructed and resolved.
281 -- The String_Literal_Subtype is built for all strings that are not
282 -- operands of a static concatenation operation. If the argument is not
283 -- a N_String_Literal node, then the call has no effect.
286 -- Build subtype of array type, with the range specified by the slice
289 -- Called after N has been resolved and evaluated, but before range checks
290 -- have been applied. This rewrites the conversion into a simpler form.
293 -- A universal_fixed expression in an universal context is unambiguous if
294 -- there is only one applicable fixed point type. Determining whether there
295 -- is only one requires a search over all visible entities, and happens
296 -- only in very pathological cases (see 6115-006).
298 function Try_User_Defined_Literal
301 -- If an operator node has a literal operand, check whether the type
302 -- of the context, or the type of the other operand has a user-defined
303 -- literal aspect that can be applied to the literal to resolve the node.
304 -- If such aspect exists, replace literal with a call to the
305 -- corresponding function and return True, return false otherwise.
307 -------------------------
308 -- Ambiguous_Character --
309 -------------------------
314 begin
318 -- First the ones in Standard
323 -- Include Wide_Wide_Character in Ada 2005 mode
329 -- Now any other types that match
339 -------------------------
340 -- Analyze_And_Resolve --
341 -------------------------
344 begin
350 begin
355 -- Versions with check(s) suppressed
357 procedure Analyze_And_Resolve
361 is
364 begin
366 declare
368 begin
374 else
375 declare
377 begin
385 and then Scope_Is_Transient
386 then
387 -- This can only happen if a transient scope was created for an inner
388 -- expression, which will be removed upon completion of the analysis
389 -- of an enclosing construct. The transient scope must have the
390 -- suppress status of the enclosing environment, not of this Analyze
391 -- call.
394 Scope_Suppress;
398 procedure Analyze_And_Resolve
401 is
404 begin
406 declare
408 begin
414 else
415 declare
417 begin
426 Scope_Suppress;
430 -------------------------------------
431 -- Has_Applicable_User_Defined_Literal --
432 -------------------------------------
434 function Has_Applicable_User_Defined_Literal
437 is
439 Literal_Aspect_Map :
459 begin
461 and then Present
463 or else
466 and then
467 Present
468 (Find_Aspect
470 then
471 Lit_Aspect :=
475 Callee :=
482 then
483 Callee :=
484 Corresponding_Primitive_Op
489 -- Handle an identifier that denotes a named number.
496 Start_String;
497 Store_String_Chars
502 else
504 Start_String;
510 Store_String_Chars
514 -- Note: Set_Etype is called below on Param1
517 Start_String;
518 Store_String_Chars
527 else
528 Error_Msg_NE
538 else
539 Param1 :=
540 Make_String_Literal
545 Call :=
546 Make_Function_Call
556 else
563 -- Conversion may be needed in case of an inherited
564 -- aspect of a derived type. For a null extension, we
565 -- use a null extension aggregate instead because the
566 -- downward type conversion would be illegal.
568 if Is_Null_Extension_Of
571 then
575 else
584 else
589 ----------------------------
590 -- Check_Discriminant_Use --
591 ----------------------------
599 begin
600 -- Any use in a spec-expression is legal
607 -- Discriminant cannot be used to constrain a scalar type
614 then
619 -- The following check catches the unusual case where a
620 -- discriminant appears within an index constraint that is part
621 -- of a larger expression within a constraint on a component,
622 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
623 -- check case of record components, and note that a similar check
624 -- should also apply in the case of discriminant constraints
625 -- below. ???
627 -- Note that the check for N_Subtype_Declaration below is to
628 -- detect the valid use of discriminants in the constraints of a
629 -- subtype declaration when this subtype declaration appears
630 -- inside the scope of a record type (which is syntactically
631 -- illegal, but which may be created as part of derived type
632 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
633 -- for more info.
637 and then not
639 and then
641 | N_Subtype_Declaration
643 then
644 Error_Msg_N
649 -- Detect a common error:
651 -- type R (D : Positive := 100) is record
652 -- Name : String (1 .. D);
653 -- end record;
655 -- The default value causes an object of type R to be allocated
656 -- with room for Positive'Last characters. The RM does not mandate
657 -- the allocation of the maximum size, but that is what GNAT does
658 -- so we should warn the programmer that there is a problem.
667 -- Return True if type T has a large enough range that any
668 -- array whose index type covered the whole range of the type
669 -- would likely raise Storage_Error.
671 ------------------------
672 -- Large_Storage_Type --
673 ------------------------
676 begin
677 -- The type is considered large if its bounds are known at
678 -- compile time and if it requires at least as many bits as
679 -- a Positive to store the possible values.
683 and then
688 -- Start of processing for Check_Large
690 begin
691 -- Check that the Disc has a large range
697 -- If the enclosing type is limited, we allocate only the
698 -- default value, not the maximum, and there is no need for
699 -- a warning.
705 -- Check that it is the high bound
709 then
713 -- Check the array allows a large range at this bound. First
714 -- find the array
728 -- Next, find the dimension
736 loop
745 -- Now, check the dimension has a large range
751 -- Warn about the danger
753 Error_Msg_N
763 -- Legal case is in index or discriminant constraint
766 | N_Discriminant_Association
767 then
769 Error_Msg_N
774 then
775 Error_Msg_N
781 -- Otherwise, context is an expression. It should not be within (i.e. a
782 -- subexpression of) a constraint for a component.
784 else
788 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
789 loop
795 -- If the discriminant is used in an expression that is a bound of a
796 -- scalar type, an Itype is created and the bounds are attached to
797 -- its range, not to the original subtype indication. Such use is of
798 -- course a double fault.
802 | N_Derived_Type_Definition
805 -- The constraint itself may be given by a subtype indication,
806 -- rather than by a more common discrete range.
809 and then
813 then
814 Error_Msg_N
820 --------------------------------
821 -- Check_For_Visible_Operator --
822 --------------------------------
825 begin
829 then
830 Error_Msg_NE -- CODEFIX
832 Error_Msg_N -- CODEFIX
837 ---------------------------------
838 -- Check_Fully_Declared_Prefix --
839 ---------------------------------
841 procedure Check_Fully_Declared_Prefix
844 is
845 begin
846 -- Check that the designated type of the prefix of a dereference is
847 -- not an incomplete type. This cannot be done unconditionally, because
848 -- dereferences of private types are legal in default expressions. This
849 -- case is taken care of in Check_Fully_Declared, called below. There
850 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
852 -- This consideration also applies to similar checks for allocators,
853 -- qualified expressions, and type conversions.
855 -- An additional exception concerns other per-object expressions that
856 -- are not directly related to component declarations, in particular
857 -- representation pragmas for tasks. These will be per-object
858 -- expressions if they depend on discriminants or some global entity.
859 -- If the task has access discriminants, the designated type may be
860 -- incomplete at the point the expression is resolved. This resolution
861 -- takes place within the body of the initialization procedure, where
862 -- the discriminant is replaced by its discriminal.
866 then
869 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
870 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
871 -- Analyze_Object_Renaming, and Freeze_Entity.
877 E_Incomplete_Type
879 then
881 else
886 ------------------------------
887 -- Check_Infinite_Recursion --
888 ------------------------------
892 -- Return the nearest enclosing declaration or statement that houses
893 -- arbitrary node N.
896 -- Determine whether call N invokes the related enclosing subprogram
897 -- with actuals that differ from the subprogram's formals.
900 -- Determine whether arbitrary node N denotes a conditional construct
903 -- Determine whether arbitrary node N denotes a control flow statement
904 -- or a construct that may contains such a statement.
907 -- Determine whether arbitrary node N appears immediately within the
908 -- statements of an entry or subprogram body.
911 -- Determine whether arbitrary node N appears immediately within the
912 -- body of an entry or subprogram, and is preceded by a single raise
913 -- statement.
916 -- Determine whether arbitrary node N denotes a raise statement
919 -- Determine whether arbitrary node N is the sole source statement in
920 -- the body of the enclosing subprogram.
923 -- Determine whether arbitrary node N is preceded by a control flow
924 -- statement.
927 -- Determine whether arbitrary node N appears within a conditional
928 -- construct.
930 ----------------------------------------
931 -- Enclosing_Declaration_Or_Statement --
932 ----------------------------------------
934 function Enclosing_Declaration_Or_Statement
936 is
939 begin
945 -- Prevent the search from going too far
957 --------------------------------------
958 -- Invoked_With_Different_Arguments --
959 --------------------------------------
967 begin
968 -- Determine whether the formals of the invoked subprogram are not
969 -- used as actuals in the call.
975 -- The current actual does not match the current formal
979 then
990 ------------------------------
991 -- Is_Conditional_Statement --
992 ------------------------------
995 begin
996 return
998 | N_Case_Expression
999 | N_Case_Statement
1000 | N_If_Expression
1001 | N_If_Statement
1002 | N_Or_Else;
1005 -------------------------------
1006 -- Is_Control_Flow_Statement --
1007 -------------------------------
1010 begin
1011 -- It is assumed that all statements may affect the control flow in
1012 -- some way. A raise statement may be expanded into a non-statement
1013 -- node.
1018 --------------------------------
1019 -- Is_Immediately_Within_Body --
1020 --------------------------------
1025 begin
1026 return
1033 --------------------
1034 -- Is_Raise_Idiom --
1035 --------------------
1041 begin
1044 -- Assume that no raise statement has been seen yet
1048 -- Examine the statements preceding the input node, skipping
1049 -- internally-generated constructs.
1054 -- Multiple raise statements violate the idiom
1070 -- At this point the node must be preceded by a raise statement,
1071 -- and the raise statement has to be the sole statement within
1072 -- the enclosing entry or subprogram body.
1074 return
1081 ------------------------
1082 -- Is_Raise_Statement --
1083 ------------------------
1086 begin
1087 -- A raise statement may be transfomed into a Raise_xxx_Error node
1089 return
1094 -----------------------
1095 -- Is_Sole_Statement --
1096 -----------------------
1101 begin
1102 -- The input node appears within the statements of an entry or
1103 -- subprogram body. Examine the statements preceding the node.
1110 -- The statement is preceded by another statement or a source
1111 -- construct. This indicates that the node does not appear by
1112 -- itself.
1116 then
1126 -- The input node is within a construct nested inside the entry or
1127 -- subprogram body.
1132 ----------------------------------------
1133 -- Preceded_By_Control_Flow_Statement --
1134 ----------------------------------------
1136 function Preceded_By_Control_Flow_Statement
1138 is
1141 begin
1145 -- Examine the statements preceding the input node
1158 -- Assume that the node is part of some control flow statement
1163 ----------------------------------
1164 -- Within_Conditional_Statement --
1165 ----------------------------------
1170 begin
1176 -- Prevent the search from going too far
1188 -- Local variables
1193 -- Start of processing for Check_Infinite_Recursion
1195 begin
1196 -- The call is assumed to be safe when the enclosing subprogram is
1197 -- invoked with actuals other than its formals.
1198 --
1199 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1200 -- begin
1201 -- ...
1202 -- Proc (A1, A2, ..., AN);
1203 -- ...
1204 -- end Proc;
1209 -- The call is assumed to be safe when the invocation of the enclosing
1210 -- subprogram depends on a conditional statement.
1211 --
1212 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1213 -- begin
1214 -- ...
1215 -- if Some_Condition then
1216 -- Proc (F1, F2, ..., FN);
1217 -- end if;
1218 -- ...
1219 -- end Proc;
1224 -- The context of the call is assumed to be safe when the invocation of
1225 -- the enclosing subprogram is preceded by some control flow statement.
1226 --
1227 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1228 -- begin
1229 -- ...
1230 -- if Some_Condition then
1231 -- ...
1232 -- end if;
1233 -- ...
1234 -- Proc (F1, F2, ..., FN);
1235 -- ...
1236 -- end Proc;
1241 -- Detect an idiom where the context of the call is preceded by a single
1242 -- raise statement.
1243 --
1244 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1245 -- begin
1246 -- raise ...;
1247 -- Proc (F1, F2, ..., FN);
1248 -- end Proc;
1254 -- At this point it is certain that infinite recursion will take place
1255 -- as long as the call is executed. Detect a case where the context of
1256 -- the call is the sole source statement within the subprogram body.
1257 --
1258 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1259 -- begin
1260 -- Proc (F1, F2, ..., FN);
1261 -- end Proc;
1262 --
1263 -- Install an explicit raise to prevent the infinite recursion.
1274 -- Otherwise infinite recursion could take place, considering other flow
1275 -- control constructs such as gotos, exit statements, etc.
1277 else
1286 ---------------------------------------
1287 -- Check_No_Direct_Boolean_Operators --
1288 ---------------------------------------
1291 begin
1294 then
1295 -- Restriction only applies to original source code
1302 -- Do style check (but skip if in instance, error is on template)
1311 ------------------------------
1312 -- Check_Parameterless_Call --
1313 ------------------------------
1319 -- If the prefix is of an access_to_subprogram type, the node must be
1320 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1321 -- interpretations are access to subprograms.
1323 ---------------------------
1324 -- Prefix_Is_Access_Subp --
1325 ---------------------------
1331 begin
1332 -- If the context is an attribute reference that can apply to
1333 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1337 in Name_Address | Name_Code_Address | Name_Access
1338 then
1343 return
1346 else
1351 then
1362 -- Start of processing for Check_Parameterless_Call
1364 begin
1365 -- Defend against junk stuff if errors already detected
1372 then
1379 -- If the context expects a value, and the name is a procedure, this is
1380 -- most likely a missing 'Access. Don't try to resolve the parameterless
1381 -- call, error will be caught when the outer call is analyzed.
1386 and then
1388 | N_Function_Call
1389 | N_Procedure_Call_Statement
1390 then
1394 -- Rewrite as call if overloadable entity that is (or could be, in the
1395 -- overloaded case) a function call. If we know for sure that the entity
1396 -- is an enumeration literal, we do not rewrite it.
1398 -- If the entity is the name of an operator, it cannot be a call because
1399 -- operators cannot have default parameters. In this case, this must be
1400 -- a string whose contents coincide with an operator name. Set the kind
1401 -- of the node appropriately.
1409 -- Rewrite as call if it is an explicit dereference of an expression of
1410 -- a subprogram access type, and the subprogram type is not that of a
1411 -- procedure or entry.
1413 or else
1416 -- Rewrite as call if it is a selected component which is a function,
1417 -- this is the case of a call to a protected function (which may be
1418 -- overloaded with other protected operations).
1420 or else
1423 or else
1425 E_Entry | E_Procedure
1428 -- If one of the above three conditions is met, rewrite as call. Apply
1429 -- the rewriting only once.
1431 then
1434 then
1436 -- This may be a prefixed call that was not fully analyzed, e.g.
1437 -- an actual in an instance.
1442 then
1450 -- The node is the name of the parameterless call. Preserve its
1451 -- descendants, which may be complex expressions.
1455 -- If overloaded, overload set belongs to new copy
1459 -- Change node to parameterless function call (note that the
1460 -- Parameter_Associations associations field is left set to Empty,
1461 -- its normal default value since there are no parameters)
1481 --------------------------------
1482 -- Is_Atomic_Ref_With_Address --
1483 --------------------------------
1488 begin
1492 else
1493 declare
1496 begin
1504 -----------------------------
1505 -- Is_Definite_Access_Type --
1506 -----------------------------
1510 begin
1516 ----------------------
1517 -- Is_Predefined_Op --
1518 ----------------------
1521 begin
1522 -- Predefined operators are intrinsic subprograms
1528 -- A call to a back-end builtin is never a predefined operator
1539 -----------------------------
1540 -- Make_Call_Into_Operator --
1541 -----------------------------
1543 procedure Make_Call_Into_Operator
1547 is
1562 -- If the operand is not universal, and the operator is given by an
1563 -- expanded name, verify that the operand has an interpretation with a
1564 -- type defined in the given scope of the operator.
1567 -- Find a type of the given class in package Pack that contains the
1568 -- operator.
1570 ---------------------------
1571 -- Operand_Type_In_Scope --
1572 ---------------------------
1579 begin
1583 else
1597 ---------------
1598 -- Type_In_P --
1599 ---------------
1605 -- Verify that node is not part of the type declaration for the
1606 -- candidate type, which would otherwise be invisible.
1608 -------------
1609 -- In_Decl --
1610 -------------
1616 begin
1625 else
1628 loop
1631 else
1640 -- Start of processing for Type_In_P
1642 begin
1643 -- If the context type is declared in the prefix package, this is the
1644 -- desired base type.
1649 else
1663 -- Start of processing for Make_Call_Into_Operator
1665 begin
1668 -- Preserve the Comes_From_Source flag on the result if the original
1669 -- call came from source. Although it is not strictly the case that the
1670 -- operator as such comes from the source, logically it corresponds
1671 -- exactly to the function call in the source, so it should be marked
1672 -- this way (e.g. to make sure that validity checks work fine).
1676 -- Ensure that the corresponding operator has the same parent as the
1677 -- original call. This guarantees that parent traversals performed by
1678 -- the ABE mechanism succeed.
1682 -- Binary operator
1692 -- Unary operator
1694 else
1700 -- If the operator is denoted by an expanded name, and the prefix is
1701 -- not Standard, but the operator is a predefined one whose scope is
1702 -- Standard, then this is an implicit_operator, inserted as an
1703 -- interpretation by the procedure of the same name. This procedure
1704 -- overestimates the presence of implicit operators, because it does
1705 -- not examine the type of the operands. Verify now that the operand
1706 -- type appears in the given scope. If right operand is universal,
1707 -- check the other operand. In the case of concatenation, either
1708 -- argument can be the component type, so check the type of the result.
1709 -- If both arguments are literals, look for a type of the right kind
1710 -- defined in the given scope. This elaborate nonsense is brought to
1711 -- you courtesy of b33302a. The type itself must be frozen, so we must
1712 -- find the type of the proper class in the given scope.
1714 -- A final wrinkle is the multiplication operator for fixed point types,
1715 -- which is defined in Standard only, and not in the scope of the
1716 -- fixed point type itself.
1721 -- If this is a package renaming, get renamed entity, which will be
1722 -- the scope of the operands if operaton is type-correct.
1728 -- If the entity being called is defined in the given package, it is
1729 -- a renaming of a predefined operator, and known to be legal.
1733 then
1736 -- Visibility does not need to be checked in an instance: if the
1737 -- operator was not visible in the generic it has been diagnosed
1738 -- already, else there is an implicit copy of it in the instance.
1746 then
1751 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1752 -- available.
1758 then
1761 else
1770 and then Is_Binary
1772 then
1778 -- Verify that the scope contains a type that corresponds to
1779 -- the given literal. Optimize the case where Pack is Standard.
1800 else
1809 else
1818 then
1821 -- If the type is defined elsewhere, and the operator is not
1822 -- defined in the given scope (by a renaming declaration, e.g.)
1823 -- then this is an error as well. If an extension of System is
1824 -- present, and the type may be defined there, Pack must be
1825 -- System itself.
1832 then
1835 else
1841 then
1848 Error_Msg_NE
1853 -- Detect a mismatch between the context type and the result type
1854 -- in the named package, which is otherwise not detected if the
1855 -- operands are universal. Check is only needed if source entity is
1856 -- an operator, not a function that renames an operator.
1863 and then not In_Instance
1864 then
1867 then
1868 -- Already checked above
1872 -- Operator may be defined in an extension of System
1877 then
1880 else
1881 -- Could we use Wrong_Type here??? (this would require setting
1882 -- Etype (N) to the actual type found where Typ was expected).
1893 else
1897 -- If this is a call to a function that renames a predefined equality,
1898 -- the renaming declaration provides a type that must be used to
1899 -- resolve the operands. This must be done now because resolution of
1900 -- the equality node will not resolve any remaining ambiguity, and it
1901 -- assumes that the first operand is not overloaded.
1906 then
1916 -- If this is an arithmetic operator and the result type is private,
1917 -- the operands and the result must be wrapped in conversion to
1918 -- expose the underlying numeric type and expand the proper checks,
1919 -- e.g. on division.
1923 when N_Op_Add
1924 | N_Op_Divide
1925 | N_Op_Expon
1926 | N_Op_Mod
1927 | N_Op_Multiply
1928 | N_Op_Rem
1929 | N_Op_Subtract
1930 =>
1933 when N_Op_Abs
1934 | N_Op_Minus
1935 | N_Op_Plus
1936 =>
1942 else
1947 -------------------
1948 -- Operator_Kind --
1949 -------------------
1951 function Operator_Kind
1954 is
1957 begin
1958 -- Use CASE statement or array???
1995 else
1999 -- Unary operators
2001 else
2010 else
2018 ----------------------------
2019 -- Preanalyze_And_Resolve --
2020 ----------------------------
2022 procedure Preanalyze_And_Resolve
2026 is
2030 Inside_Preanalysis_Without_Freezing;
2031 begin
2036 Inside_Preanalysis_Without_Freezing :=
2043 -- Normally, we suppress all checks for this preanalysis. There is no
2044 -- point in processing them now, since they will be applied properly
2045 -- and in the proper location when the default expressions reanalyzed
2046 -- and reexpanded later on. We will also have more information at that
2047 -- point for possible suppression of individual checks.
2049 -- However, in SPARK mode, most expansion is suppressed, and this
2050 -- later reanalysis and reexpansion may not occur. SPARK mode does
2051 -- require the setting of checking flags for proof purposes, so we
2052 -- do the SPARK preanalysis without suppressing checks.
2054 -- This special handling for SPARK mode is required for example in the
2055 -- case of Ada 2012 constructs such as quantified expressions, which are
2056 -- expanded in two separate steps.
2060 else
2064 Expander_Mode_Restore;
2069 Inside_Preanalysis_Without_Freezing :=
2073 pragma Assert
2077 ----------------------------
2078 -- Preanalyze_And_Resolve --
2079 ----------------------------
2082 begin
2086 -- Version without context type
2091 begin
2098 Expander_Mode_Restore;
2102 ------------------------------------------
2103 -- Preanalyze_With_Freezing_And_Resolve --
2104 ------------------------------------------
2106 procedure Preanalyze_With_Freezing_And_Resolve
2109 is
2110 begin
2114 ----------------------------------
2115 -- Replace_Actual_Discriminants --
2116 ----------------------------------
2123 -- Comment needed???
2125 -------------------
2126 -- Process_Discr --
2127 -------------------
2132 begin
2138 then
2154 -- Start of processing for Replace_Actual_Discriminants
2156 begin
2160 -- Allow the replacement of concurrent discriminants in GNATprove even
2161 -- though this is a light expansion activity. Note that generic units
2162 -- are not modified.
2167 else
2183 -------------
2184 -- Resolve --
2185 -------------
2201 -- Determine whether a node comes from a predefined library unit or
2202 -- Standard.
2205 -- Try and fix up a literal so that it matches its expected type. New
2206 -- literals are manufactured if necessary to avoid cascaded errors.
2209 -- Additional diagnostics when an ambiguous call has an ambiguous
2210 -- argument (typically a controlling actual).
2213 -- Called when attempt at resolving current expression fails
2215 ------------------------------------
2216 -- Comes_From_Predefined_Lib_Unit --
2217 -------------------------------------
2220 begin
2221 return
2225 --------------------
2226 -- Patch_Up_Value --
2227 --------------------
2230 begin
2247 then
2252 Char_Literal_Value =>
2268 -------------------------------
2269 -- Report_Ambiguous_Argument --
2270 -------------------------------
2277 begin
2281 then
2284 -- Examine possible interpretations, and adapt the message
2285 -- for inherited subprograms declared by a type derivation.
2293 else
2301 -- Additional message and hint if the ambiguity involves an Ada 2022
2302 -- container aggregate.
2307 -----------------------
2308 -- Resolution_Failed --
2309 -----------------------
2312 begin
2315 -- Set the type to the desired one to minimize cascaded errors. Note
2316 -- that this is an approximation and does not work in all cases.
2323 -- The caller will return without calling the expander, so we need
2324 -- to set the analyzed flag. Note that it is fine to set Analyzed
2325 -- to True even if we are in the middle of a shallow analysis,
2326 -- (see the spec of sem for more details) since this is an error
2327 -- situation anyway, and there is no point in repeating the
2328 -- analysis later (indeed it won't work to repeat it later, since
2329 -- we haven't got a clear resolution of which entity is being
2330 -- referenced.)
2336 -- Start of processing for Resolve
2338 begin
2343 -- Access attribute on remote subprogram cannot be used for a non-remote
2344 -- access-to-subprogram type.
2348 | Name_Unrestricted_Access
2349 | Name_Unchecked_Access
2355 then
2356 Error_Msg_N
2362 -- If the context is a Remote_Access_To_Subprogram, access attributes
2363 -- must be resolved with the corresponding fat pointer. There is no need
2364 -- to check for the attribute name since the return type of an
2365 -- attribute is never a remote type.
2370 then
2371 declare
2379 begin
2380 -- Check that Typ is a remote access-to-subprogram type
2384 -- Prefix (N) must statically denote a remote subprogram
2385 -- declared in a package specification.
2389 Attr = Attribute_Unrestricted_Access
2390 then
2405 or else
2407 then
2409 Error_Msg_N
2411 N);
2414 -- If we are generating code in distributed mode, perform
2415 -- semantic checks against corresponding remote entities.
2417 if Expander_Active
2419 then
2420 Check_Subtype_Conformant
2422 Old_Id => Designated_Type
2448 then
2453 -- Return if already analyzed
2460 -- Any case of Any_Type as the Etype value means that we had a
2461 -- previous error.
2470 -- The resolution of an Expression_With_Actions is determined by
2471 -- its Expression, but if the node comes from source it is a
2472 -- Declare_Expression and requires scope management.
2477 else
2484 -- If not overloaded, then we know the type, and all that needs doing
2485 -- is to check that this type is compatible with the context.
2491 -- In the overloaded case, we must select the interpretation that
2492 -- is compatible with the context (i.e. the type passed to Resolve)
2494 else
2495 -- Loop through possible interpretations
2504 -- We are only interested in interpretations that are compatible
2505 -- with the expected type, any other interpretations are ignored.
2510 Write_Eol;
2513 else
2514 -- Skip the current interpretation if it is disabled by an
2515 -- abstract operator. This action is performed only when the
2516 -- type against which we are resolving is the same as the
2517 -- type of the interpretation.
2523 then
2531 -- First matching interpretation
2539 -- Matching interpretation that is not the first, maybe an
2540 -- error, but there are some cases where preference rules are
2541 -- used to choose between the two possibilities. These and
2542 -- some more obscure cases are handled in Disambiguate.
2544 else
2545 -- If the current statement is part of a predefined library
2546 -- unit, then all interpretations which come from user level
2547 -- packages should not be considered. Check previous and
2548 -- current one.
2556 -- Previous interpretation must be discarded
2566 -- Otherwise apply further disambiguation steps
2571 -- Disambiguation has succeeded. Skip the remaining
2572 -- interpretations.
2582 else
2583 -- Before we issue an ambiguity complaint, check for the
2584 -- case of a subprogram call where at least one of the
2585 -- arguments is Any_Type, and if so suppress the message,
2586 -- since it is a cascaded error. This can also happen for
2587 -- a generalized indexing operation.
2592 then
2593 declare
2597 begin
2613 Write_Eol;
2626 then
2631 then
2635 -- Not that special case, so issue message using the flag
2636 -- Ambiguous to control printing of the header message
2637 -- only at the start of an ambiguous set.
2642 then
2643 Error_Msg_N
2646 else
2647 Error_Msg_NE -- CODEFIX
2655 Error_Msg_N
2657 else
2658 Error_Msg_N -- CODEFIX
2664 then
2665 Report_Ambiguous_Argument;
2671 -- By default, the error message refers to the candidate
2672 -- interpretation. But if it is a predefined operator, it
2673 -- is implicitly declared at the declaration of the type
2674 -- of the operand. Recover the sloc of that declaration
2675 -- for the error message.
2681 Standard_Standard
2682 then
2687 then
2695 Standard_Standard
2696 then
2701 then
2705 -- If this is an indirect call, use the subprogram_type
2706 -- in the message, to have a meaningful location. Also
2707 -- indicate if this is an inherited operation, created
2708 -- by a type declaration.
2713 then
2715 Error_Msg_Sloc :=
2717 else
2724 then
2725 -- Special-case the message for universal_fixed
2726 -- operators, which are not declared with the type
2727 -- of the operand, but appear forever in Standard.
2731 then
2732 Error_Msg_N
2735 else
2736 Error_Msg_N
2740 elsif
2742 then
2743 Error_Msg_N
2745 else
2746 Error_Msg_N -- CODEFIX
2753 -- We have a matching interpretation, Expr_Type is the type
2754 -- from this interpretation, and Seen is the entity.
2756 -- For an operator, just set the entity name. The type will be
2757 -- set by the specific operator resolution routine.
2764 | N_Character_Literal
2765 | N_Delta_Aggregate
2766 | N_If_Expression
2767 then
2770 -- AI05-0139-2: Expression is overloaded because type has
2771 -- implicit dereference. The context may be the one that
2772 -- requires implicit dereferemce.
2778 -- If the expression is an entity, generate a reference
2779 -- to it, as this is not done for an overloaded construct
2780 -- during analysis.
2784 then
2787 -- Examine access discriminants of entity type,
2788 -- to check whether one of them yields the
2789 -- expected type.
2791 declare
2795 begin
2816 then
2817 -- If the node is a general indexing, the dereference is
2818 -- is inserted when resolving the rewritten form, else
2819 -- insert it now.
2823 then
2827 -- For an explicit dereference, attribute reference, range,
2828 -- short-circuit form (which is not an operator node), or call
2829 -- with a name that is an explicit dereference, there is
2830 -- nothing to be done at this point.
2833 | N_And_Then
2834 | N_Explicit_Dereference
2835 | N_Identifier
2836 | N_Indexed_Component
2837 | N_Or_Else
2838 | N_Range
2839 | N_Selected_Component
2840 | N_Slice
2842 then
2845 -- For procedure or function calls, set the type of the name,
2846 -- and also the entity pointer for the prefix.
2850 then
2857 then
2862 -- For all other cases, just set the type of the Name
2864 else
2872 -- Move to next interpretation
2880 -- At this stage Found indicates whether or not an acceptable
2881 -- interpretation exists. If not, then we have an error, except that if
2882 -- the context is Any_Type as a result of some other error, then we
2883 -- suppress the error report.
2888 -- If type we are looking for is Void, then this is the procedure
2889 -- call case, and the error is simply that what we gave is not a
2890 -- procedure name (we think of procedure calls as expressions with
2891 -- types internally, but the user doesn't think of them this way).
2895 -- Special case message if function used as a procedure
2900 then
2901 Error_Msg_NE
2904 Error_Msg_N
2908 -- Otherwise give general message (not clear what cases this
2909 -- covers, but no harm in providing for them).
2911 else
2917 -- Otherwise we do have a subexpression with the wrong type
2919 -- Check for the case of an allocator which uses an access type
2920 -- instead of the designated type. This is a common error and we
2921 -- specialize the message, posting an error on the operand of the
2922 -- allocator, complaining that we expected the designated type of
2923 -- the allocator.
2929 then
2933 -- Check for view mismatch on Null in instances, for which the
2934 -- view-swapping mechanism has no identifier.
2940 then
2945 -- Check for an aggregate. Sometimes we can get bogus aggregates
2946 -- from misuse of parentheses, and we are about to complain about
2947 -- the aggregate without even looking inside it.
2949 -- Instead, if we have an aggregate of type Any_Composite, then
2950 -- analyze and resolve the component fields, and then only issue
2951 -- another message if we get no errors doing this (otherwise
2952 -- assume that the errors in the aggregate caused the problem).
2956 then
2959 then
2968 -- Disable expansion in any case. If there is a type mismatch
2969 -- it may be fatal to try to expand the aggregate. The flag
2970 -- would otherwise be set to false when the error is posted.
2974 declare
2976 -- Check one aggregate, and set Found to True if we have a
2977 -- definite error in any of its elements
2980 -- Check one element of aggregate and set Found to True if
2981 -- we definitely have an error in the element.
2983 ----------------
2984 -- Check_Aggr --
2985 ----------------
2990 begin
3003 -- If this is a default-initialized component, then
3004 -- there is nothing to check. The box will be
3005 -- replaced by the appropriate call during late
3006 -- expansion.
3010 then
3019 ----------------
3020 -- Check_Elmt --
3021 ----------------
3024 begin
3025 -- If we have a nested aggregate, go inside it (to
3026 -- attempt a naked analyze-resolve of the aggregate can
3027 -- cause undesirable cascaded errors). Do not resolve
3028 -- expression if it needs a type from context, as for
3029 -- integer * fixed expression.
3034 else
3039 then
3049 begin
3054 -- If node is a literal and context type has a user-defined
3055 -- literal aspect, rewrite node as a call to the corresponding
3056 -- function, which plays the role of an implicit conversion.
3059 N_Numeric_Or_String_Literal | N_Identifier
3061 then
3066 -- Looks like we have a type error, but check for special case
3067 -- of Address wanted, integer found, with the configuration pragma
3068 -- Allow_Integer_Address active. If we have this case, introduce
3069 -- an unchecked conversion to allow the integer expression to be
3070 -- treated as an Address. The reverse case of integer wanted,
3071 -- Address found, is treated in an analogous manner.
3078 -- Under relaxed RM semantics silently replace occurrences of null
3079 -- by System.Null_Address.
3087 -- That special Allow_Integer_Address check did not apply, so we
3088 -- have a real type error. If an error message was issued already,
3089 -- Found got reset to True, so if it's still False, issue standard
3090 -- Wrong_Type message.
3094 declare
3097 begin
3103 -- Protected operation: retrieve operation name
3107 else
3112 Error_Msg_NE
3118 declare
3122 begin
3129 Error_Msg_NE
3135 else
3139 -- Recognize the case of a quantified expression being mistaken
3140 -- for an iterated component association because the user
3141 -- forgot the "all" or "some" keyword after "for". Because the
3142 -- error message starts with "missing ALL", we automatically
3143 -- benefit from the associated CODEFIX, which requires that
3144 -- the message is located on the identifier following "for"
3145 -- in order for the CODEFIX to insert "all" in the right place.
3150 = N_Iterated_Component_Association
3152 then
3153 Error_Msg_N -- CODEFIX
3157 -- For an operator with no interpretation, check whether
3158 -- one of its operands may be a user-defined literal.
3162 then
3165 else
3171 Resolution_Failed;
3174 -- Test if we have more than one interpretation for the context
3177 Resolution_Failed;
3180 -- Only one interpretation
3182 else
3183 -- Prevent implicit conversions between access-to-subprogram types
3184 -- with different strub modes. Explicit conversions are acceptable in
3185 -- some circumstances. We don't have to be concerned about data or
3186 -- access-to-data types. Conversions between data types can safely
3187 -- drop or add strub attributes from types, because strub effects are
3188 -- associated with the locations rather than values. E.g., converting
3189 -- a hypothetical Strub_Integer variable to Integer would load the
3190 -- value from the variable, enabling stack scrabbing for the
3191 -- enclosing subprogram, and then convert the value to Integer. As
3192 -- for conversions between access-to-data types, that's no different
3193 -- from any other case of type punning.
3199 then
3200 Check_Same_Strub_Mode
3204 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3205 -- the "+" on T is abstract, and the operands are of universal type,
3206 -- the above code will have (incorrectly) resolved the "+" to the
3207 -- universal one in Standard. Therefore check for this case and give
3208 -- an error. We can't do this earlier, because it would cause legal
3209 -- cases to get errors (when some other type has an abstract "+").
3215 then
3220 then
3221 Error_Msg_NE
3230 -- Here we have an acceptable interpretation for the context
3232 -- Propagate type information and normalize tree for various
3233 -- predefined operations. If the context only imposes a class of
3234 -- types, rather than a specific type, propagate the actual type
3235 -- downward.
3241 Typ = Any_Discrete
3242 then
3245 -- Any_Fixed is legal in a real context only if a specific fixed-
3246 -- point type is imposed. If Norman Cohen can be confused by this,
3247 -- it deserves a separate message.
3251 then
3258 -- A user-defined operator is transformed into a function call at
3259 -- this point, so that further processing knows that operators are
3260 -- really operators (i.e. are predefined operators). User-defined
3261 -- operators that are intrinsic are just renamings of the predefined
3262 -- ones, and need not be turned into calls either, but if they rename
3263 -- a different operator, we must transform the node accordingly.
3264 -- Instantiations of Unchecked_Conversion are intrinsic but are
3265 -- treated as functions, even if given an operator designator.
3270 then
3275 and then
3277 N_Subprogram_Renaming_Declaration
3278 then
3281 -- If the node is rewritten, it will be fully resolved in
3282 -- Rewrite_Renamed_Operator.
3291 when N_Aggregate =>
3292 Resolve_Aggregate (N, Ctx_Type);
3294 when N_Allocator =>
3295 Resolve_Allocator (N, Ctx_Type);
3297 when N_Short_Circuit =>
3298 Resolve_Short_Circuit (N, Ctx_Type);
3300 when N_Attribute_Reference =>
3301 Resolve_Attribute (N, Ctx_Type);
3303 when N_Case_Expression =>
3304 Resolve_Case_Expression (N, Ctx_Type);
3306 when N_Character_Literal =>
3307 Resolve_Character_Literal (N, Ctx_Type);
3309 when N_Delta_Aggregate =>
3310 Resolve_Delta_Aggregate (N, Ctx_Type);
3312 when N_Expanded_Name =>
3313 Resolve_Entity_Name (N, Ctx_Type);
3315 when N_Explicit_Dereference =>
3316 Resolve_Explicit_Dereference (N, Ctx_Type);
3318 when N_Expression_With_Actions =>
3319 Resolve_Expression_With_Actions (N, Ctx_Type);
3321 when N_Extension_Aggregate =>
3322 Resolve_Extension_Aggregate (N, Ctx_Type);
3324 when N_Function_Call =>
3325 Resolve_Call (N, Ctx_Type);
3327 when N_Identifier =>
3328 Resolve_Entity_Name (N, Ctx_Type);
3330 when N_If_Expression =>
3331 Resolve_If_Expression (N, Ctx_Type);
3333 when N_Indexed_Component =>
3334 Resolve_Indexed_Component (N, Ctx_Type);
3336 when N_Integer_Literal =>
3337 Resolve_Integer_Literal (N, Ctx_Type);
3339 when N_Membership_Test =>
3340 Resolve_Membership_Op (N, Ctx_Type);
3342 when N_Null =>
3343 Resolve_Null (N, Ctx_Type);
3345 when N_Op_And
3346 | N_Op_Or
3347 | N_Op_Xor
3348 =>
3349 Resolve_Logical_Op (N, Ctx_Type);
3351 when N_Op_Eq
3352 | N_Op_Ne
3353 =>
3354 Resolve_Equality_Op (N, Ctx_Type);
3356 when N_Op_Ge
3357 | N_Op_Gt
3358 | N_Op_Le
3359 | N_Op_Lt
3360 =>
3361 Resolve_Comparison_Op (N, Ctx_Type);
3363 when N_Op_Not =>
3364 Resolve_Op_Not (N, Ctx_Type);
3366 when N_Op_Add
3367 | N_Op_Divide
3368 | N_Op_Mod
3369 | N_Op_Multiply
3370 | N_Op_Rem
3371 | N_Op_Subtract
3372 =>
3373 Resolve_Arithmetic_Op (N, Ctx_Type);
3375 when N_Op_Concat =>
3376 Resolve_Op_Concat (N, Ctx_Type);
3378 when N_Op_Expon =>
3379 Resolve_Op_Expon (N, Ctx_Type);
3381 when N_Op_Abs
3382 | N_Op_Minus
3383 | N_Op_Plus
3384 =>
3385 Resolve_Unary_Op (N, Ctx_Type);
3387 when N_Op_Shift =>
3388 Resolve_Shift (N, Ctx_Type);
3390 when N_Procedure_Call_Statement =>
3391 Resolve_Call (N, Ctx_Type);
3393 when N_Operator_Symbol =>
3394 Resolve_Operator_Symbol (N, Ctx_Type);
3396 when N_Qualified_Expression =>
3397 Resolve_Qualified_Expression (N, Ctx_Type);
3399 -- Why is the following null, needs a comment ???
3401 when N_Quantified_Expression =>
3402 null;
3404 when N_Raise_Expression =>
3405 Resolve_Raise_Expression (N, Ctx_Type);
3407 when N_Raise_xxx_Error =>
3408 Set_Etype (N, Ctx_Type);
3410 when N_Range =>
3411 Resolve_Range (N, Ctx_Type);
3413 when N_Real_Literal =>
3414 Resolve_Real_Literal (N, Ctx_Type);
3416 when N_Reference =>
3417 Resolve_Reference (N, Ctx_Type);
3419 when N_Selected_Component =>
3420 Resolve_Selected_Component (N, Ctx_Type);
3422 when N_Slice =>
3423 Resolve_Slice (N, Ctx_Type);
3425 when N_String_Literal =>
3426 Resolve_String_Literal (N, Ctx_Type);
3428 when N_Target_Name =>
3429 Resolve_Target_Name (N, Ctx_Type);
3431 when N_Type_Conversion =>
3432 Resolve_Type_Conversion (N, Ctx_Type);
3434 when N_Unchecked_Expression =>
3435 Resolve_Unchecked_Expression (N, Ctx_Type);
3437 when N_Unchecked_Type_Conversion =>
3438 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3439 end case;
3441 -- Mark relevant use-type and use-package clauses as effective using
3442 -- the original node because constant folding may have occurred and
3443 -- removed references that need to be examined.
3445 if Nkind (Original_Node (N)) in N_Op then
3446 Mark_Use_Clauses (Original_Node (N));
3447 end if;
3449 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3450 -- expression of an anonymous access type that occurs in the context
3451 -- of a named general access type, except when the expression is that
3452 -- of a membership test. This ensures proper legality checking in
3453 -- terms of allowed conversions (expressions that would be illegal to
3454 -- convert implicitly are allowed in membership tests).
3456 if Ada_Version >= Ada_2012
3457 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3458 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3459 and then Nkind (Parent (N)) not in N_Membership_Test
3460 then
3461 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3462 Analyze_And_Resolve (N, Ctx_Type);
3463 end if;
3465 -- If the subexpression was replaced by a non-subexpression, then
3466 -- all we do is to expand it. The only legitimate case we know of
3467 -- is converting procedure call statement to entry call statements,
3468 -- but there may be others, so we are making this test general.
3470 if Nkind (N) not in N_Subexpr then
3471 Debug_A_Exit ("resolving ", N, " (done)");
3472 Expand (N);
3473 return;
3474 end if;
3476 -- The expression is definitely NOT overloaded at this point, so
3477 -- we reset the Is_Overloaded flag to avoid any confusion when
3478 -- reanalyzing the node.
3480 Set_Is_Overloaded (N, False);
3482 -- Freeze expression type, entity if it is a name, and designated
3483 -- type if it is an allocator (RM 13.14(10,11,13)).
3485 -- Now that the resolution of the type of the node is complete, and
3486 -- we did not detect an error, we can expand this node. We skip the
3487 -- expand call if we are in a default expression, see section
3488 -- "Handling of Default Expressions" in Sem spec.
3490 Debug_A_Exit ("resolving ", N, " (done)");
3492 -- We unconditionally freeze the expression, even if we are in
3493 -- default expression mode (the Freeze_Expression routine tests this
3494 -- flag and only freezes static types if it is set).
3496 -- Ada 2012 (AI05-177): The declaration of an expression function
3497 -- does not cause freezing, but we never reach here in that case.
3498 -- Here we are resolving the corresponding expanded body, so we do
3499 -- need to perform normal freezing.
3501 -- As elsewhere we do not emit freeze node within a generic.
3503 if not Inside_A_Generic then
3504 Freeze_Expression (N);
3505 end if;
3507 -- Now we can do the expansion
3509 Expand (N);
3510 end if;
3511 end Resolve;
3513 -------------
3514 -- Resolve --
3515 -------------
3517 -- Version with check(s) suppressed
3519 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3520 begin
3521 if Suppress = All_Checks then
3522 declare
3523 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3524 begin
3525 Scope_Suppress.Suppress := (others => True);
3526 Resolve (N, Typ);
3527 Scope_Suppress.Suppress := Sva;
3528 end;
3530 else
3531 declare
3532 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3533 begin
3534 Scope_Suppress.Suppress (Suppress) := True;
3535 Resolve (N, Typ);
3536 Scope_Suppress.Suppress (Suppress) := Svg;
3537 end;
3538 end if;
3539 end Resolve;
3541 -------------
3542 -- Resolve --
3543 -------------
3545 -- Version with implicit type
3547 procedure Resolve (N : Node_Id) is
3548 begin
3549 Resolve (N, Etype (N));
3550 end Resolve;
3552 ---------------------
3553 -- Resolve_Actuals --
3554 ---------------------
3556 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3557 Loc : constant Source_Ptr := Sloc (N);
3558 A : Node_Id;
3559 A_Typ : Entity_Id := Empty; -- init to avoid warning
3560 F : Entity_Id;
3561 F_Typ : Entity_Id;
3562 Prev : Node_Id := Empty;
3563 Orig_A : Node_Id;
3564 Real_F : Entity_Id := Empty; -- init to avoid warning
3566 Real_Subp : Entity_Id;
3567 -- If the subprogram being called is an inherited operation for
3568 -- a formal derived type in an instance, Real_Subp is the subprogram
3569 -- that will be called. It may have different formal names than the
3570 -- operation of the formal in the generic, so after actual is resolved
3571 -- the name of the actual in a named association must carry the name
3572 -- of the actual of the subprogram being called.
3574 procedure Check_Aliased_Parameter;
3575 -- Check rules on aliased parameters and related accessibility rules
3576 -- in (RM 3.10.2 (10.2-10.4)).
3578 procedure Check_Argument_Order;
3579 -- Performs a check for the case where the actuals are all simple
3580 -- identifiers that correspond to the formal names, but in the wrong
3581 -- order, which is considered suspicious and cause for a warning.
3583 procedure Check_Prefixed_Call;
3584 -- If the original node is an overloaded call in prefix notation,
3586 -- Try_Object_Operation has already verified that there is a valid
3587 -- interpretation, but the form of the actual can only be determined
3588 -- once the primitive operation is identified.
3591 -- Emit an error concerning the illegal usage of an effectively volatile
3592 -- object for reading in interfering context (SPARK RM 7.1.3(10)).
3595 -- If the actual is missing in a call, insert in the actuals list
3596 -- an instance of the default expression. The insertion is always
3597 -- a named association.
3600 -- Check whether T1 and T2, or their full views, are derived from a
3601 -- common type. Used to enforce the restrictions on array conversions
3602 -- of AI95-00246.
3605 -- Predicate to determine whether an actual that is a concatenation
3606 -- will be evaluated statically and does not need a transient scope.
3607 -- This must be determined before the actual is resolved and expanded
3608 -- because if needed the transient scope must be introduced earlier.
3610 -----------------------------
3611 -- Check_Aliased_Parameter --
3612 -----------------------------
3617 begin
3625 else
3632 -- In a generic body assume the worst for generic formals:
3633 -- they can have a constrained partial view (AI05-041).
3637 and then not Object_Type_Has_Constrained_Partial_View
3639 then
3642 else
3647 else
3659 then
3667 then
3668 Error_Msg_N
3674 --------------------------
3675 -- Check_Argument_Order --
3676 --------------------------
3679 begin
3680 -- Nothing to do if no parameters, or original node is neither a
3681 -- function call nor a procedure call statement (happens in the
3682 -- operator-transformed-to-function call case), or the call is to an
3683 -- operator symbol (which is usually in infix form), or the call does
3684 -- not come from source, or this warning is off.
3686 if not Warn_On_Parameter_Order
3692 N_Defining_Operator_Symbol)
3694 then
3698 declare
3701 begin
3702 -- Nothing to do if only one parameter
3708 -- Here if at least two arguments
3710 declare
3716 -- Set True if an out of order case is found
3718 begin
3719 -- Collect identifier names of actuals, fail if any actual is
3720 -- not a simple identifier, and record max length of name.
3726 else
3732 -- If we got this far, all actuals are identifiers and the list
3733 -- of their names is stored in the Actuals array.
3738 -- If we ran out of formals, that's odd, probably an error
3739 -- which will be detected elsewhere, but abandon the search.
3745 -- If name matches and is in order OK
3750 else
3751 -- If no match, see if it is elsewhere in list and if so
3752 -- flag potential wrong order if type is compatible.
3756 and then
3758 then
3764 -- No match
3772 -- If Formals left over, also probably an error, skip warning
3778 -- Here we give the warning if something was out of order
3781 Error_Msg_N
3788 -------------------------
3789 -- Check_Prefixed_Call --
3790 -------------------------
3799 begin
3800 -- Check whether the call is a prefixed call, with or without
3801 -- additional actuals.
3804 or else
3810 then
3813 then
3814 -- Introduce dereference on object in prefix
3816 New_A :=
3824 then
3825 -- Introduce an implicit 'Access in prefix
3828 Error_Msg_NE
3844 ---------------------------------------
3845 -- Flag_Effectively_Volatile_Objects --
3846 ---------------------------------------
3850 -- Determine whether arbitrary node N denotes an effectively volatile
3851 -- object for reading and if it does, emit an error.
3853 -----------------
3854 -- Flag_Object --
3855 -----------------
3860 begin
3862 -- Do not consider nested function calls because they have
3863 -- already been processed during their own resolution.
3874 and then
3878 then
3879 Error_Msg_N
3893 -- Start of processing for Flag_Effectively_Volatile_Objects
3895 begin
3899 --------------------
3900 -- Insert_Default --
3901 --------------------
3907 begin
3908 -- Missing argument in call, nothing to insert
3913 else
3914 -- Note that we do a full New_Copy_Tree, so that any associated
3915 -- Itypes are properly copied. This may not be needed any more,
3916 -- but it does no harm as a safety measure. Defaults of a generic
3917 -- formal may be out of bounds of the corresponding actual (see
3918 -- cc1311b) and an additional check may be required.
3920 Actval :=
3921 New_Copy_Tree
3926 -- Propagate dimension information, if any.
3932 then
3938 then
3941 then
3942 -- If default is a real literal, do not introduce a
3943 -- conversion whose effect may depend on the run-time
3944 -- size of universal real.
3948 else
3959 -- Resolve aggregates with their base type, to avoid scope
3960 -- anomalies: the subtype was first built in the subprogram
3961 -- declaration, and the current call may be nested.
3965 else
3969 else
3972 -- See note above concerning aggregates
3976 then
3979 -- Resolve entities with their own type, which may differ from
3980 -- the type of a reference in a generic context (the view
3981 -- swapping mechanism did not anticipate the re-analysis of
3982 -- default values in calls).
3987 else
3992 -- If default is a tag indeterminate function call, propagate tag
3993 -- to obtain proper dispatching.
3997 then
4002 -- If the default expression raises constraint error, then just
4003 -- silently replace it with an N_Raise_Constraint_Error node, since
4004 -- we already gave the warning on the subprogram spec. If node is
4005 -- already a Raise_Constraint_Error leave as is, to prevent loops in
4006 -- the warnings removal machinery.
4010 then
4019 Assoc :=
4024 -- Case of insertion is first named actual
4028 then
4035 else
4039 else
4043 -- Case of insertion is not first named actual
4045 else
4046 Set_Next_Named_Actual
4058 -------------------
4059 -- Same_Ancestor --
4060 -------------------
4066 begin
4069 then
4075 then
4082 --------------------------
4083 -- Static_Concatenation --
4084 --------------------------
4087 begin
4094 -- Concatenation is static when both operands are static and
4095 -- the concatenation operator is a predefined one.
4098 and then
4100 and then
4105 declare
4107 begin
4110 and then
4114 else
4120 -- Start of processing for Resolve_Actuals
4122 begin
4123 Check_Argument_Order;
4127 and then In_Instance
4130 then
4132 else
4137 Check_Prefixed_Call;
4151 -- If we have an error in any formal or actual, indicated by a type
4152 -- of Any_Type, then abandon resolution attempt, and set result type
4153 -- to Any_Type.
4160 -- For the peculiar case of a user-defined comparison or equality
4161 -- operator that does not return a boolean type, the operands may
4162 -- have been ambiguous for the predefined operator and, therefore,
4163 -- marked with Any_Type. Since the operation has been resolved to
4164 -- the user-defined operator, that is irrelevant, so reset Etype.
4167 | N_Op_Ge
4168 | N_Op_Gt
4169 | N_Op_Le
4170 | N_Op_Lt
4171 | N_Op_Ne
4173 then
4176 -- Also skip this if the actual is a Raise_Expression, whose type
4177 -- is imposed from context.
4182 else
4188 -- Case where actual is present
4190 -- If the actual is an entity, generate a reference to it now. We
4191 -- do this before the actual is resolved, because a formal of some
4192 -- protected subprogram, or a task discriminant, will be rewritten
4193 -- during expansion, and the source entity reference may be lost.
4198 then
4199 -- Annotate the tree by creating a variable reference marker when
4200 -- the actual denotes a variable reference, in case the reference
4201 -- is folded or optimized away. The variable reference marker is
4202 -- automatically saved for later examination by the ABE Processing
4203 -- phase. The status of the reference is set as follows:
4205 -- status mode
4206 -- read IN, IN OUT
4207 -- write IN OUT, OUT
4209 if Needs_Variable_Reference_Marker
4212 then
4213 Build_Variable_Reference_Marker
4224 then
4231 -- RM 6.4.1(12): For an out parameter that is passed by
4232 -- copy, the formal parameter object is created, and:
4234 -- * For an access type, the formal parameter is initialized
4235 -- from the value of the actual, without checking that the
4236 -- value satisfies any constraint, any predicate, or any
4237 -- exclusion of the null value.
4239 -- * For a scalar type that has the Default_Value aspect
4240 -- specified, the formal parameter is initialized from the
4241 -- value of the actual, without checking that the value
4242 -- satisfies any constraint or any predicate.
4243 -- I do not understand why this case is included??? this is
4244 -- not a case where an OUT parameter is treated as IN OUT.
4246 -- * For a composite type with discriminants or that has
4247 -- implicit initial values for any subcomponents, the
4248 -- behavior is as for an in out parameter passed by copy.
4250 -- Hence for these cases we generate the read reference now
4251 -- (the write reference will be generated later by
4252 -- Note_Possible_Modification).
4255 and then
4257 or else
4259 and then
4261 or else
4264 or else Is_Partially_Initialized_Type
4266 then
4276 then
4277 -- If style checking mode on, check match of formal name
4285 -- If the formal is Out or In_Out, do not resolve and expand the
4286 -- conversion, because it is subsequently expanded into explicit
4287 -- temporaries and assignments. However, the object of the
4288 -- conversion can be resolved. An exception is the case of tagged
4289 -- type conversion with a class-wide actual. In that case we want
4290 -- the tag check to occur and no temporary will be needed (no
4291 -- representation change can occur) and the parameter is passed by
4292 -- reference, so we go ahead and resolve the type conversion.
4293 -- Another exception is the case of reference to component or
4294 -- subcomponent of a bit-packed array, in which case we want to
4295 -- defer expansion to the point the in and out assignments are
4296 -- performed.
4302 then
4303 declare
4306 begin
4307 -- Check RM 4.6 (24.2/2)
4311 then
4312 -- In a view conversion, the conversion must be legal in
4313 -- both directions, and thus both component types must be
4314 -- aliased, or neither (4.6 (8)).
4316 -- Check RM 4.6 (24.8/2)
4320 then
4321 -- This normally illegal conversion is legal in an
4322 -- expanded instance body because of RM 12.3(11).
4323 -- At runtime, conversion must create a new object.
4326 Error_Msg_N
4331 -- Check RM 4.6 (24/3)
4334 -- Check view conv between unrelated by ref array
4335 -- types.
4339 then
4340 Error_Msg_N
4344 -- In Ada 2005 mode, check view conversion component
4345 -- type cannot be private, tagged, or volatile. Note
4346 -- that we only apply this to source conversions. The
4347 -- generated code can contain conversions which are
4348 -- not subject to this test, and we cannot extract the
4349 -- component type in such cases since it is not
4350 -- present.
4354 then
4355 declare
4358 begin
4363 then
4364 Error_Msg_N
4374 -- AI12-0074 & AI12-0377
4375 -- Check 6.4.1: If the mode is out, the actual parameter is
4376 -- a view conversion, and the type of the formal parameter
4377 -- is a scalar type, then either:
4378 -- - the target and operand type both do not have the
4379 -- Default_Value aspect specified; or
4380 -- - the target and operand type both have the
4381 -- Default_Value aspect specified, and there shall exist
4382 -- a type (other than a root numeric type) that is an
4383 -- ancestor of both the target type and the operand
4384 -- type.
4388 then
4391 then
4392 Error_Msg_N
4397 then
4398 Error_Msg_N
4405 -- Resolve expression if conversion is all OK
4410 then
4414 -- If the actual is a function call that returns a limited
4415 -- unconstrained object that needs finalization, create a
4416 -- transient scope for it, so that it can receive the proper
4417 -- finalization list.
4419 elsif Expander_Active
4425 then
4429 -- A small optimization: if one of the actuals is a concatenation
4430 -- create a block around a procedure call to recover stack space.
4431 -- This alleviates stack usage when several procedure calls in
4432 -- the same statement list use concatenation. We do not perform
4433 -- this wrapping for code statements, where the argument is a
4434 -- static string, and we want to preserve warnings involving
4435 -- sequences of such statements.
4437 elsif Expander_Active
4443 then
4447 else
4451 and then
4454 then
4455 Error_Msg_N
4468 -- (Ada 2005: AI-251): If the actual is an allocator whose
4469 -- directly designated type is a class-wide interface, we build
4470 -- an anonymous access type to use it as the type of the
4471 -- allocator. Later, when the subprogram call is expanded, if
4472 -- the interface has a secondary dispatch table the expander
4473 -- will add a type conversion to force the correct displacement
4474 -- of the pointer.
4477 declare
4481 begin
4482 -- Displace the pointer to the object to reference its
4483 -- secondary dispatch table.
4487 then
4493 -- Ada 2005, AI-162:If the actual is an allocator, the
4494 -- innermost enclosing statement is the master of the
4495 -- created object. This needs to be done with expansion
4496 -- enabled only, otherwise the transient scope will not
4497 -- be removed in the expansion of the wrapped construct.
4499 if Expander_Active
4502 then
4503 Establish_Transient_Scope
4513 -- (Ada 2005): The call may be to a primitive operation of a
4514 -- tagged synchronized type, declared outside of the type. In
4515 -- this case the controlling actual must be converted to its
4516 -- corresponding record type, which is the formal type. The
4517 -- actual may be a subtype, either because of a constraint or
4518 -- because it is a generic actual, so use base type to locate
4519 -- concurrent type.
4526 then
4527 -- If the actual is overloaded, look for an interpretation
4528 -- that has a synchronized type.
4533 else
4534 declare
4538 begin
4543 then
4553 declare
4556 begin
4559 else
4563 -- Tagged synchronized type (case 1): the actual is a
4564 -- concurrent type.
4568 then
4570 Unchecked_Convert_To
4574 -- Tagged synchronized type (case 2): the formal is a
4575 -- concurrent type.
4578 and then Present
4583 then
4586 -- Common case
4588 else
4593 -- Not a synchronized operation
4595 else
4603 -- An actual cannot be an untagged formal incomplete type
4608 then
4609 Error_Msg_N
4613 -- has warnings suppressed, then we reset Never_Set_In_Source for
4614 -- the calling entity. The reason for this is to catch cases like
4615 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4616 -- uses trickery to modify an IN parameter.
4623 then
4627 -- Perform error checks for IN and IN OUT parameters
4631 -- Check unset reference. For scalar parameters, it is clearly
4632 -- wrong to pass an uninitialized value as either an IN or
4633 -- IN-OUT parameter. For composites, it is also clearly an
4634 -- error to pass a completely uninitialized value as an IN
4635 -- parameter, but the case of IN OUT is trickier. We prefer
4636 -- not to give a warning here. For example, suppose there is
4637 -- a routine that sets some component of a record to False.
4638 -- It is perfectly reasonable to make this IN-OUT and allow
4639 -- either initialized or uninitialized records to be passed
4640 -- in this case.
4642 -- For partially initialized composite values, we also avoid
4643 -- warnings, since it is quite likely that we are passing a
4644 -- partially initialized value and only the initialized fields
4645 -- will in fact be read in the subprogram.
4650 then
4654 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4655 -- actual to a nested call, since this constitutes a reading of
4656 -- the parameter, which is not allowed.
4661 then
4666 -- In -gnatd.q mode, forget that a given array is constant when
4667 -- it is passed as an IN parameter to a foreign-convention
4668 -- subprogram. This is in case the subprogram evilly modifies the
4669 -- object. Of course, correct code would use IN OUT.
4671 if Debug_Flag_Dot_Q
4677 then
4681 -- Case of OUT or IN OUT parameter
4685 -- For an Out parameter, check for useless assignment. Note
4686 -- that we can't set Last_Assignment this early, because we may
4687 -- kill current values in Resolve_Call, and that call would
4688 -- clobber the Last_Assignment field.
4690 -- Note: call Warn_On_Useless_Assignment before doing the check
4691 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4692 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4693 -- reflects the last assignment, not this one.
4700 then
4705 -- Validate the form of the actual. Note that the call to
4706 -- Is_OK_Variable_For_Out_Formal generates the required
4707 -- reference in this case.
4709 -- A call to an initialization procedure for an aggregate
4710 -- component may initialize a nested component of a constant
4711 -- designated object. In this context the object is variable.
4715 then
4721 then
4722 Error_Msg_N
4727 Error_Msg_N
4734 -- What's the following about???
4738 else
4739 Kill_All_Checks;
4748 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4752 -- Apply predicate tests except in certain special cases. Note
4753 -- that it might be more consistent to apply these only when
4754 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4755 -- for the outbound predicate tests ??? In any case indicate
4756 -- the function being called, for better warnings if the call
4757 -- leads to an infinite recursion.
4763 -- Apply required constraint checks
4776 then
4779 -- For view conversions of a discriminated object, apply
4780 -- check to object itself, the conversion alreay has the
4781 -- proper type.
4785 then
4792 then
4798 then
4801 else
4805 -- Ada 2005 (AI-231): Note that the controlling parameter case
4806 -- already existed in Ada 95, which is partially checked
4807 -- elsewhere (see Checks), and we don't want the warning
4808 -- message to differ.
4813 then
4815 Apply_Compile_Time_Constraint_Error
4821 Apply_Compile_Time_Constraint_Error
4830 -- Checks for OUT parameters and IN OUT parameters
4834 -- If there is a type conversion, make sure the return value
4835 -- meets the constraints of the variable before the conversion.
4840 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4841 -- which would prevent the check from being generated.
4842 -- This is for Starlet only though, so long obsolete.
4847 then
4849 else
4850 Apply_Scalar_Range_Check
4854 -- In addition the return value must meet the constraints
4855 -- of the object type (see the comment below).
4859 else
4860 Apply_Range_Check
4864 -- If no conversion, apply scalar range checks and length check
4865 -- based on the subtype of the actual (NOT that of the formal).
4866 -- This indicates that the check takes place on return from the
4867 -- call. During expansion the required constraint checks are
4868 -- inserted. In GNATprove mode, in the absence of expansion,
4869 -- the flag indicates that the returned value is valid.
4871 else
4877 then
4880 else
4885 -- Note: we do not apply the predicate checks for the case of
4886 -- OUT and IN OUT parameters. They are instead applied in the
4887 -- Expand_Actuals routine in Exp_Ch6.
4890 -- If the formal is of an unconstrained array subtype with fixed
4891 -- lower bound, then sliding to that bound may be needed.
4897 -- An actual associated with an access parameter is implicitly
4898 -- converted to the anonymous access type of the formal and must
4899 -- satisfy the legality checks for access conversions.
4903 Error_Msg_N
4907 -- If the actual is an access selected component of a variable,
4908 -- the call may modify its designated object. It is reasonable
4909 -- to treat this as a potential modification of the enclosing
4910 -- record, to prevent spurious warnings that it should be
4911 -- declared as a constant, because intuitively programmers
4912 -- regard the designated subcomponent as part of the record.
4917 then
4922 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
4926 then
4929 then
4930 Error_Msg_NE
4933 Error_Msg_N
4938 then
4939 Error_Msg_NE
4942 Error_Msg_N
4947 then
4948 Error_Msg_NE
4951 Error_Msg_N
4955 -- Check for nonatomic subcomponent of a full access object
4956 -- in Ada 2022 (RM C.6 (12)).
4961 then
4962 Error_Msg_N
4965 Error_Msg_NE
4971 -- Check that subprograms don't have improper controlling
4972 -- arguments (RM 3.9.2 (9)).
4974 -- A primitive operation may have an access parameter of an
4975 -- incomplete tagged type, but a dispatching call is illegal
4976 -- if the type is still incomplete.
4982 declare
4984 begin
4988 then
4989 Error_Msg_NE
5000 -- Apply legality rule 3.9.2 (9/1)
5002 -- Skip this check on helpers and indirect-call wrappers built to
5003 -- support class-wide preconditions.
5008 and then not In_Instance
5011 then
5016 Error_Msg_NE
5020 -- Apply the checks described in 3.10.2(27): if the context is a
5021 -- specific access-to-object, the actual cannot be class-wide.
5022 -- Use base type to exclude access_to_subprogram cases.
5029 and then
5034 -- Disable these checks for call to imported C++ subprograms
5036 and then not
5040 then
5041 Error_Msg_N
5046 Error_Msg_NE
5051 Check_Aliased_Parameter;
5055 -- If it is a named association, treat the selector_name as a
5056 -- proper identifier, and mark the corresponding entity.
5060 -- Ignore reference in SPARK mode, as it refers to an entity not
5061 -- in scope at the point of reference, so the reference should
5062 -- be ignored for computing effects of subprograms.
5064 and then not GNATprove_Mode
5065 then
5066 -- If subprogram is overridden, use name of formal that
5067 -- is being called.
5073 else
5087 -- The following checks are only relevant when SPARK_Mode is on as
5088 -- they are not standard Ada legality rule. Internally generated
5089 -- temporaries are ignored.
5093 -- Inspect the expression and flag each effectively volatile
5094 -- object for reading as illegal because it appears within
5095 -- an interfering context. Note that this is usually done
5096 -- in Resolve_Entity_Name, but when the effectively volatile
5097 -- object for reading appears as an actual in a call, the call
5098 -- must be resolved first.
5103 -- A formal parameter of a specific tagged type whose related
5104 -- subprogram is subject to pragma Extensions_Visible with value
5105 -- "False" cannot act as an actual in a subprogram with value
5106 -- "True" (SPARK RM 6.1.7(3)).
5108 -- No check needed for helpers and indirect-call wrappers built to
5109 -- support class-wide preconditions.
5113 Extensions_Visible_True
5115 then
5116 Error_Msg_N
5119 Error_Msg_NE
5123 -- The actual parameter of a Ghost subprogram whose formal is of
5124 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5132 then
5133 Error_Msg_NE
5139 else
5144 -- (AI12-0397): The target of a subprogram call that occurs within
5145 -- the expression of an Default_Initial_Condition aspect and has
5146 -- an actual that is the current instance of the type must be
5147 -- either a primitive of the type or a class-wide subprogram,
5148 -- because the type of the current instance in such an aspect is
5149 -- considered to be a notional formal derived type whose only
5150 -- operations correspond to the primitives of the enclosing type.
5151 -- Nonprimitives can be called, but the current instance must be
5152 -- converted rather than passed directly. Note that a current
5153 -- instance of a type with DIC will occur as a reference to an
5154 -- in-mode formal of an enclosing DIC procedure or partial DIC
5155 -- procedure. (It seems that this check should perhaps also apply
5156 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5157 -- aspects???)
5165 -- We check Comes_From_Source to exclude inherited primitives
5166 -- from being flagged, because such subprograms turn out to not
5167 -- always have the Is_Primitive flag set. ???
5173 then
5174 Error_Msg_NE
5181 -- Case where actual is not present
5183 else
5184 Insert_Default;
5195 -----------------------
5196 -- Resolve_Allocator --
5197 -----------------------
5209 procedure Check_Allocator_Discrim_Accessibility
5212 -- Check that accessibility level associated with an access discriminant
5213 -- initialized in an allocator by the expression Disc_Exp is not deeper
5214 -- than the level of the allocator type Alloc_Typ. An error message is
5215 -- issued if this condition is violated. Specialized checks are done for
5216 -- the cases of a constraint expression which is an access attribute or
5217 -- an access discriminant.
5219 procedure Check_Allocator_Discrim_Accessibility_Exprs
5222 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5223 -- across all expressions within a given conditional expression.
5226 -- If the allocator is an actual in a call, it is allowed to be class-
5227 -- wide when the context is not because it is a controlling actual.
5229 -------------------------------------------
5230 -- Check_Allocator_Discrim_Accessibility --
5231 -------------------------------------------
5233 procedure Check_Allocator_Discrim_Accessibility
5236 is
5237 begin
5240 then
5241 Error_Msg_N
5244 -- When the expression is an Access attribute the level of the prefix
5245 -- object must not be deeper than that of the allocator's type.
5249 Attribute_Access
5250 and then Static_Accessibility_Level
5253 then
5254 Error_Msg_N
5256 Disc_Exp);
5258 -- When the expression is an access discriminant the check is against
5259 -- the level of the prefix object.
5263 and then Static_Accessibility_Level
5266 then
5267 Error_Msg_N
5269 Disc_Exp);
5271 -- All other cases are legal
5273 else
5278 -------------------------------------------------
5279 -- Check_Allocator_Discrim_Accessibility_Exprs --
5280 -------------------------------------------------
5282 procedure Check_Allocator_Discrim_Accessibility_Exprs
5285 is
5289 begin
5290 -- When conditional expressions are constant folded we know at
5291 -- compile time which expression to check - so don't bother with
5292 -- the rest of the cases.
5297 -- Non-constant-folded if expressions
5300 -- Check both expressions if they are still present in the face
5301 -- of expansion.
5308 Check_Allocator_Discrim_Accessibility_Exprs
5313 -- Non-constant-folded case expressions
5316 -- Check all alternatives
5320 Check_Allocator_Discrim_Accessibility_Exprs
5326 -- Base case, check the accessibility of the original node of the
5327 -- expression.
5329 else
5334 ----------------------------
5335 -- In_Dispatching_Context --
5336 ----------------------------
5341 begin
5347 -- Start of processing for Resolve_Allocator
5349 begin
5350 -- Replace general access with specific type
5360 -- For qualified expression, resolve the expression using the given
5361 -- subtype (nothing to do for type mark, subtype indication)
5366 and then not In_Dispatching_Context
5367 then
5368 Error_Msg_N
5372 -- Do a full resolution to apply constraint and predicate checks
5377 -- Allocators generated by the build-in-place expansion mechanism
5378 -- are explicitly marked as coming from source but do not need to be
5379 -- checked for limited initialization. To exclude this case, ensure
5380 -- that the parent of the allocator is a source node.
5381 -- The return statement constructed for an Expression_Function does
5382 -- not come from source but requires a limited check.
5386 and then
5388 or else
5392 and then not In_Instance_Body
5393 then
5396 Error_Msg_N
5399 else
5400 Error_Msg_N
5408 -- Calls to build-in-place functions are not currently supported in
5409 -- allocators for access types associated with a simple storage pool.
5410 -- Supporting such allocators may require passing additional implicit
5411 -- parameters to build-in-place functions (or a significant revision
5412 -- of the current b-i-p implementation to unify the handling for
5413 -- multiple kinds of storage pools). ???
5417 then
5418 declare
5421 begin
5423 and then
5424 Present (Get_Rep_Pragma
5426 then
5427 Error_Msg_N
5434 -- A special accessibility check is needed for allocators that
5435 -- constrain access discriminants. The level of the type of the
5436 -- expression used to constrain an access discriminant cannot be
5437 -- deeper than the type of the allocator (in contrast to access
5438 -- parameters, where the level of the actual can be arbitrary).
5440 -- We can't use Valid_Conversion to perform this check because in
5441 -- general the type of the allocator is unrelated to the type of
5442 -- the access discriminant.
5446 then
5453 then
5456 -- Get the first component expression of the aggregate
5466 else
5470 else
5476 Check_Allocator_Discrim_Accessibility_Exprs
5490 else
5495 else
5504 -- For a subtype mark or subtype indication, freeze the subtype
5506 else
5510 Error_Msg_N
5514 -- A special accessibility check is needed for allocators that
5515 -- constrain access discriminants. The level of the type of the
5516 -- expression used to constrain an access discriminant cannot be
5517 -- deeper than the type of the allocator (in contrast to access
5518 -- parameters, where the level of the actual can be arbitrary).
5519 -- We can't use Valid_Conversion to perform this check because
5520 -- in general the type of the allocator is unrelated to the type
5521 -- of the access discriminant.
5526 then
5536 else
5540 Check_Allocator_Discrim_Accessibility_Exprs
5551 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5552 -- check that the level of the type of the created object is not deeper
5553 -- than the level of the allocator's access type, since extensions can
5554 -- now occur at deeper levels than their ancestor types. This is a
5555 -- static accessibility level check; a run-time check is also needed in
5556 -- the case of an initialized allocator with a class-wide argument (see
5557 -- Expand_Allocator_Expression).
5561 then
5562 declare
5565 begin
5570 else
5576 then
5579 Error_Msg_N
5589 -- Do not apply Ada 2005 accessibility checks on a class-wide
5590 -- allocator if the type given in the allocator is a formal
5591 -- type or within a formal package. A run-time check will be
5592 -- performed in the instance.
5596 then
5597 Error_Msg_N
5605 -- Check for allocation from an empty storage pool. But do not complain
5606 -- if it's a return statement for a build-in-place function, because the
5607 -- allocator is there just in case the caller uses an allocator. If the
5608 -- caller does use an allocator, it will be caught at the call site.
5612 then
5615 -- If the context is an unchecked conversion, as may happen within an
5616 -- inlined subprogram, the allocator is being resolved with its own
5617 -- anonymous type. In that case, if the target type has a specific
5618 -- storage pool, it must be inherited explicitly by the allocator type.
5622 then
5623 Set_Associated_Storage_Pool
5631 -- Check that an allocator with task parts isn't for a nested access
5632 -- type when restriction No_Task_Hierarchy applies.
5636 then
5640 -- An illegal allocator may be rewritten as a raise Program_Error
5641 -- statement.
5645 -- Avoid coextension processing for an allocator that is the
5646 -- expansion of a build-in-place function call.
5650 N_Qualified_Expression
5652 N_Function_Call
5653 and then Is_Expanded_Build_In_Place_Call
5655 then
5658 else
5659 -- An anonymous access discriminant is the definition of a
5660 -- coextension.
5664 N_Discriminant_Specification
5665 then
5666 declare
5670 begin
5673 -- Ada 2012 AI05-0052: If the designated type of the
5674 -- allocator is limited, then the allocator shall not
5675 -- be used to define the value of an access discriminant
5676 -- unless the discriminated type is immutably limited.
5681 then
5682 Error_Msg_N
5685 N);
5689 -- Avoid marking an allocator as a dynamic coextension if it is
5690 -- within a static construct.
5695 -- Finalization and deallocation of coextensions utilizes an
5696 -- approximate implementation which does not directly adhere
5697 -- to the semantic rules. Warn on potential issues involving
5698 -- coextensions.
5701 Error_Msg_N
5704 else
5705 Error_Msg_N
5711 -- Cleanup for potential static coextensions
5713 else
5717 -- Anonymous access-to-controlled objects are not finalized on
5718 -- time because this involves run-time ownership and currently
5719 -- this property is not available. In rare cases the object may
5720 -- not be finalized at all. Warn on potential issues involving
5721 -- anonymous access-to-controlled objects.
5725 then
5726 Error_Msg_N
5736 -- Report a simple error: if the designated object is a local task,
5737 -- its body has not been seen yet, and its activation will fail an
5738 -- elaboration check.
5745 then
5751 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5752 -- type with a task component on a subpool. This action must raise
5753 -- Program_Error at runtime.
5759 then
5771 ---------------------------
5772 -- Resolve_Arithmetic_Op --
5773 ---------------------------
5775 -- Used for resolving all arithmetic operators except exponentiation
5786 -- We do the resolution using the base type, because intermediate values
5787 -- in expressions always are of the base type, not a subtype of it.
5790 -- Returns True if N is in a context that expects "any real type"
5793 -- Return True iff given type is Integer or universal real/integer
5796 -- Choose type of integer literal in fixed-point operation to conform
5797 -- to available fixed-point type. T is the type of the other operand,
5798 -- which is needed to determine the expected type of N.
5801 -- Set operand type to T if universal
5803 -------------------------------
5804 -- Expected_Type_Is_Any_Real --
5805 -------------------------------
5808 begin
5809 -- N is the expression after "delta" in a fixed_point_definition;
5810 -- see RM-3.5.9(6):
5813 | N_Decimal_Fixed_Point_Definition
5815 -- N is one of the bounds in a real_range_specification;
5816 -- see RM-3.5.7(5):
5818 | N_Real_Range_Specification
5820 -- N is the expression of a delta_constraint;
5821 -- see RM-J.3(3):
5823 | N_Delta_Constraint;
5826 -----------------------------
5827 -- Is_Integer_Or_Universal --
5828 -----------------------------
5835 begin
5840 else
5845 then
5856 ----------------------------
5857 -- Set_Mixed_Mode_Operand --
5858 ----------------------------
5864 begin
5867 -- A universal integer literal is resolved as standard integer
5868 -- except in the case of a fixed-point result, where we leave it
5869 -- as universal (to be handled by Exp_Fixd later on)
5873 else
5880 then
5881 -- A universal real can appear in a fixed-type context. We resolve
5882 -- the literal with that context, even though this might raise an
5883 -- exception prematurely (the other operand may be zero).
5890 then
5891 -- Integer arg in mixed-mode operation. Resolve with universal
5892 -- type, in case preference rule must be applied.
5898 -- If the operand is part of a fixed multiplication operation,
5899 -- a conversion will be applied to each operand, so resolve it
5900 -- with its own type.
5905 else
5906 -- Not a mixed-mode operation, resolve with context
5913 -- N may itself be a mixed-mode operation, so use context type
5920 then
5921 -- Must be (fixed * fixed) operation, operand must have one
5922 -- compatible interpretation.
5929 then
5930 -- C * F(X) in a fixed context, where C is a real literal or a
5931 -- fixed-point expression. F must have either a fixed type
5932 -- interpretation or an integer interpretation, but not both.
5939 else
5946 else
5954 -- Reanalyze the literal with the fixed type of the context. If
5955 -- context is Universal_Fixed, we are within a conversion, leave
5956 -- the literal as a universal real because there is no usable
5957 -- fixed type, and the target of the conversion plays no role in
5958 -- the resolution.
5960 declare
5964 begin
5967 else
5973 then
5975 else
5983 -- A universal real conditional expression can appear in a fixed-type
5984 -- context and must be resolved with that context to facilitate the
5985 -- code generation in the back end. However, If the context is
5986 -- Universal_fixed (i.e. as an operand of a multiplication/division
5987 -- involving a fixed-point operand) the conditional expression must
5988 -- resolve to a unique visible fixed_point type, normally Duration.
5993 then
5997 else
6001 else
6006 ----------------------
6007 -- Set_Operand_Type --
6008 ----------------------
6011 begin
6017 -- Start of processing for Resolve_Arithmetic_Op
6019 begin
6024 then
6028 -- Special-case for mixed-mode universal expressions or fixed point type
6029 -- operation: each argument is resolved separately. The same treatment
6030 -- is required if one of the operands of a fixed point operation is
6031 -- universal real, since in this case we don't do a conversion to a
6032 -- specific fixed-point type (instead the expander handles the case).
6034 -- Set the type of the node to its universal interpretation because
6035 -- legality checks on an exponentiation operand need the context.
6040 then
6051 or else
6054 then
6059 -- If context is a fixed type and one operand is integer, the other
6060 -- is resolved with the type of the context.
6065 then
6072 then
6076 -- If both operands are universal and the context is a floating
6077 -- point type, the operands are resolved to the type of the context.
6083 else
6088 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6089 -- multiplying operators from being used when the expected type is
6090 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6091 -- some cases where the expected type is actually Any_Real;
6092 -- Expected_Type_Is_Any_Real takes care of that case.
6096 then
6100 N_Type_Conversion | N_Unchecked_Type_Conversion
6101 then
6108 else
6112 N_Type_Conversion | N_Unchecked_Type_Conversion
6113 then
6114 Error_Msg_N
6119 -- The expected type is "any real type" in contexts like
6121 -- type T is delta <universal_fixed-expression> ...
6123 -- in which case we need to set the type to Universal_Real
6124 -- so that static expression evaluation will work properly.
6128 else
6138 then
6143 -- If no previous errors, this is only possible if one operand is
6144 -- overloaded and the context is universal. Resolve as such.
6149 else
6151 and then
6153 then
6157 -- If the context is Universal_Fixed and the operands are also
6158 -- universal fixed, this is an error, unless there is only one
6159 -- applicable fixed_point type (usually Duration).
6167 else
6172 else
6177 -- If one of the arguments was resolved to a non-universal type.
6178 -- label the result of the operation itself with the same type.
6179 -- Do the same for the universal argument, if any.
6191 -- Set overflow and division checking bit
6198 -- Give warning if explicit division by zero
6202 then
6208 or else
6211 then
6212 -- Specialize the warning message according to the operation.
6213 -- When SPARK_Mode is On, force a warning instead of an error
6214 -- in that case, as this likely corresponds to deactivated
6215 -- code. The following warnings are for the case
6220 -- For division, we have two cases, for float division
6221 -- of an unconstrained float type, on a machine where
6222 -- Machine_Overflows is false, we don't get an exception
6223 -- at run-time, but rather an infinity or Nan. The Nan
6224 -- case is pretty obscure, so just warn about infinities.
6228 and then not Machine_Overflows_On_Target
6229 then
6230 Error_Msg_N
6234 -- For all other cases, we get a Constraint_Error
6236 else
6237 Apply_Compile_Time_Constraint_Error
6244 Apply_Compile_Time_Constraint_Error
6250 Apply_Compile_Time_Constraint_Error
6255 -- Division by zero can only happen with division, rem,
6256 -- and mod operations.
6262 -- Otherwise just set the flag to check at run time
6264 else
6269 -- If Restriction No_Implicit_Conditionals is active, then it is
6270 -- violated if either operand can be negative for mod, or for rem
6271 -- if both operands can be negative.
6275 then
6276 declare
6283 -- Set if corresponding operand might be negative
6285 begin
6286 Determine_Range
6290 Determine_Range
6294 -- Check if we will be generating conditionals. There are two
6295 -- cases where that can happen, first for REM, the only case
6296 -- is largest negative integer mod -1, where the division can
6297 -- overflow, but we still have to give the right result. The
6298 -- front end generates a test for this annoying case. Here we
6299 -- just test if both operands can be negative (that's what the
6300 -- expander does, so we match its logic here).
6302 -- The second case is mod where either operand can be negative.
6303 -- In this case, the back end has to generate additional tests.
6306 or else
6308 then
6319 ------------------
6320 -- Resolve_Call --
6321 ------------------
6336 begin
6337 -- Preserve relevant elaboration-related attributes of the context which
6338 -- are no longer available or very expensive to recompute once analysis,
6339 -- resolution, and expansion are over.
6341 Mark_Elaboration_Attributes
6347 -- The context imposes a unique interpretation with type Typ on a
6348 -- procedure or function call. Find the entity of the subprogram that
6349 -- yields the expected type, and propagate the corresponding formal
6350 -- constraints on the actuals. The caller has established that an
6351 -- interpretation exists, and emitted an error if not unique.
6353 -- First deal with the case of a call to an access-to-subprogram,
6354 -- dereference made explicit in Analyze_Call.
6360 else
6361 -- Find the interpretation whose type (a subprogram type) has a
6362 -- return type that is compatible with the context. Analysis of
6363 -- the node has established that one exists.
6382 -- If the prefix is not an entity, then resolve it
6388 -- For an indirect call, we always invalidate checks, since we do not
6389 -- know whether the subprogram is local or global. Yes we could do
6390 -- better here, e.g. by knowing that there are no local subprograms,
6391 -- but it does not seem worth the effort. Similarly, we kill all
6392 -- knowledge of current constant values.
6394 Kill_Current_Values;
6396 -- If this is a procedure call which is really an entry call, do
6397 -- the conversion of the procedure call to an entry call. Protected
6398 -- operations use the same circuitry because the name in the call
6399 -- can be an arbitrary expression with special resolution rules.
6403 then
6410 -- Annotate the tree by creating a call marker in case the original
6411 -- call is transformed by expansion. The call marker is automatically
6412 -- saved for later examination by the ABE Processing phase.
6416 -- Kill checks and constant values, as above for indirect case
6417 -- Who knows what happens when another task is activated?
6419 Kill_Current_Values;
6422 -- Normal subprogram call with name established in Resolve
6428 -- Otherwise we must have the case of an overloaded call
6430 else
6433 -- Initialize Nam to prevent warning (we know it will be assigned
6434 -- in the loop below, but the compiler does not know that).
6450 -- Check that a call to Current_Task does not occur in an entry body
6453 declare
6456 begin
6458 loop
6461 -- Exclude calls that occur within the default of a formal
6462 -- parameter of the entry, since those are evaluated outside
6463 -- of the body.
6470 then
6473 Error_Msg_NE
6487 -- Check that a procedure call does not occur in the context of the
6488 -- entry call statement of a conditional or timed entry call. Note that
6489 -- the case of a call to a subprogram renaming of an entry will also be
6490 -- rejected. The test for N not being an N_Entry_Call_Statement is
6491 -- defensive, covering the possibility that the processing of entry
6492 -- calls might reach this point due to later modifications of the code
6493 -- above.
6498 then
6502 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6503 -- for a procedure_or_entry_call, the procedure_name or
6504 -- procedure_prefix of the procedure_call_statement shall denote
6505 -- an entry renamed by a procedure, or (a view of) a primitive
6506 -- subprogram of a limited interface whose first parameter is
6507 -- a controlling parameter.
6512 then
6513 Error_Msg_N
6518 -- Check that this is not a call to a protected procedure or entry from
6519 -- within a protected function.
6523 -- Freeze the subprogram name if not in a spec-expression. Note that
6524 -- we freeze procedure calls as well as function calls. Procedure calls
6525 -- are not frozen according to the rules (RM 13.14(14)) because it is
6526 -- impossible to have a procedure call to a non-frozen procedure in
6527 -- pure Ada, but in the code that we generate in the expander, this
6528 -- rule needs extending because we can generate procedure calls that
6529 -- need freezing.
6531 -- In Ada 2012, expression functions may be called within pre/post
6532 -- conditions of subsequent functions or expression functions. Such
6533 -- calls do not freeze when they appear within generated bodies,
6534 -- (including the body of another expression function) which would
6535 -- place the freeze node in the wrong scope. An expression function
6536 -- is frozen in the usual fashion, by the appearance of a real body,
6537 -- or at the end of a declarative part. However an implicit call to
6538 -- an expression function may appear when it is part of a default
6539 -- expression in a call to an initialization procedure, and must be
6540 -- frozen now, even if the body is inserted at a later point.
6541 -- Otherwise, the call freezes the expression if expander is active,
6542 -- for example as part of an object declaration.
6545 and then not In_Spec_Expression
6547 and then
6550 then
6553 -- Force freeze of expression function in call
6562 -- For a predefined operator, the type of the result is the type imposed
6563 -- by context, except for a predefined operation on universal fixed.
6564 -- Otherwise the type of the call is the type returned by the subprogram
6565 -- being called.
6572 -- If the subprogram returns an array type, and the context requires the
6573 -- component type of that array type, the node is really an indexing of
6574 -- the parameterless call. Resolve as such. A pathological case occurs
6575 -- when the type of the component is an access to the array type. In
6576 -- this case the call is truly ambiguous. If the call is to an intrinsic
6577 -- subprogram, it can't be an indexed component. This check is necessary
6578 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6579 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6580 -- pointers to the same array), the compiler gets confused and does an
6581 -- infinite recursion.
6584 and then
6587 or else
6590 and then
6593 then
6594 declare
6599 begin
6600 -- If this is a parameterless call there is no ambiguity and the
6601 -- call has the type of the function.
6610 -- Annotate the tree by creating a call marker in case the
6611 -- original call is transformed by expansion. The call marker
6612 -- is automatically saved for later examination by the ABE
6613 -- Processing phase.
6620 then
6621 Error_Msg_N
6623 else
6626 -- The called entity may be an explicit dereference, in which
6627 -- case there is no entity to set.
6635 or else
6637 and then
6639 then
6642 -- Indexed call to a parameterless function
6644 Index_Node :=
6646 Prefix =>
6649 else
6650 -- An Ada 2005 prefixed call to a primitive operation
6651 -- whose first parameter is the prefix. This prefix was
6652 -- prepended to the parameter list, which is actually a
6653 -- list of indexes. Remove the prefix in order to build
6654 -- the proper indexed component.
6656 Index_Node :=
6658 Prefix =>
6661 Parameter_Associations =>
6662 New_List
6667 -- Preserve the parenthesis count of the node
6671 -- Since we are correcting a node classification error made
6672 -- by the parser, we call Replace rather than Rewrite.
6683 -- Annotate the tree by creating a call marker in case
6684 -- the original call is transformed by expansion. The call
6685 -- marker is automatically saved for later examination by
6686 -- the ABE Processing phase.
6697 else
6698 -- If the called function is not declared in the main unit and it
6699 -- returns the limited view of type then use the available view (as
6700 -- is done in Try_Object_Operation) to prevent back-end confusion;
6701 -- for the function entity itself. The call must appear in a context
6702 -- where the nonlimited view is available. If the function entity is
6703 -- in the extended main unit then no action is needed, because the
6704 -- back end handles this case. In either case the type of the call
6705 -- is the nonlimited view.
6709 then
6716 else
6721 -- In the case where the call is to an overloaded subprogram, Analyze
6722 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6723 -- such a case Normalize_Actuals needs to be called once more to order
6724 -- the actuals correctly. Otherwise the call will have the ordering
6725 -- given by the last overloaded subprogram whether this is the correct
6726 -- one being called or not.
6733 -- In any case, call is fully resolved now. Reset Overload flag, to
6734 -- prevent subsequent overload resolution if node is analyzed again
6739 -- A Ghost entity must appear in a specific context
6745 -- If we are calling the current subprogram from immediately within its
6746 -- body, then that is the case where we can sometimes detect cases of
6747 -- infinite recursion statically. Do not try this in case restriction
6748 -- No_Recursion is in effect anyway, and do it only for source calls.
6753 -- Issue warning for possible infinite recursion in the absence
6754 -- of the No_Recursion restriction.
6760 then
6761 -- Here we detected and flagged an infinite recursion, so we do
6762 -- not need to test the case below for further warnings. Also we
6763 -- are all done if we now have a raise SE node.
6769 -- If call is to immediately containing subprogram, then check for
6770 -- the case of a possible run-time detectable infinite recursion.
6772 else
6776 -- Ada 2022 (AI12-0075): Static functions are never allowed
6777 -- to make a recursive call, as specified by 6.8(5.4/5).
6780 Error_Msg_N
6789 -- Although in general case, recursion is not statically
6790 -- checkable, the case of calling an immediately containing
6791 -- subprogram is easy to catch.
6797 -- If the recursive call is to a parameterless subprogram,
6798 -- then even if we can't statically detect infinite
6799 -- recursion, this is pretty suspicious, and we output a
6800 -- warning. Furthermore, we will try later to detect some
6801 -- cases here at run time by expanding checking code (see
6802 -- Detect_Infinite_Recursion in package Exp_Ch6).
6804 -- If the recursive call is within a handler, do not emit a
6805 -- warning, because this is a common idiom: loop until input
6806 -- is correct, catch illegal input in handler and restart.
6812 then
6813 -- For the case of a procedure call. We give the message
6814 -- only if the call is the first statement in a sequence
6815 -- of statements, or if all previous statements are
6816 -- simple assignments. This is simply a heuristic to
6817 -- decrease false positives, without losing too many good
6818 -- warnings. The idea is that these previous statements
6819 -- may affect global variables the procedure depends on.
6820 -- We also exclude raise statements, that may arise from
6821 -- constraint checks and are probably unrelated to the
6822 -- intended control flow.
6826 then
6827 declare
6829 begin
6833 | N_Raise_Constraint_Error
6834 then
6843 -- Do not give warning if we are in a conditional context
6845 declare
6847 begin
6853 then
6858 -- Here warning is to be issued
6874 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6878 -- If subprogram name is a predefined operator, it was given in
6879 -- functional notation. Replace call node with operator node, so
6880 -- that actuals can be resolved appropriately.
6892 -- Create a transient scope if the resulting type requires it
6894 -- There are several notable exceptions:
6896 -- a) In init procs, the transient scope overhead is not needed, and is
6897 -- even incorrect when the call is a nested initialization call for a
6898 -- component whose expansion may generate adjust calls. However, if the
6899 -- call is some other procedure call within an initialization procedure
6900 -- (for example a call to Create_Task in the init_proc of the task
6901 -- run-time record) a transient scope must be created around this call.
6903 -- b) Enumeration literal pseudo-calls need no transient scope
6905 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6906 -- functions) do not use the secondary stack even though the return
6907 -- type may be unconstrained.
6909 -- d) Calls to a build-in-place function, since such functions may
6910 -- allocate their result directly in a target object, and cases where
6911 -- the result does get allocated in the secondary stack are checked for
6912 -- within the specialized Exp_Ch6 procedures for expanding those
6913 -- build-in-place calls.
6915 -- e) Calls to inlinable expression functions do not use the secondary
6916 -- stack (since the call will be replaced by its returned object).
6918 -- f) If the subprogram is marked Inline_Always, then even if it returns
6919 -- an unconstrained type the call does not require use of the secondary
6920 -- stack. However, inlining will only take place if the body to inline
6921 -- is already present. It may not be available if e.g. the subprogram is
6922 -- declared in a child instance.
6924 -- g) If the subprogram is a static expression function and the call is
6925 -- a static call (the actuals are all static expressions), then we never
6926 -- want to create a transient scope (this could occur in the case of a
6927 -- static string-returning call).
6933 then
6941 then
6944 -- A return statement from an ignored Ghost function does not use the
6945 -- secondary stack (or any other one).
6947 elsif Expander_Active
6951 then
6954 -- If the call appears within the bounds of a loop, it will be
6955 -- rewritten and reanalyzed, nothing left to do here.
6962 -- A protected function cannot be called within the definition of the
6963 -- enclosing protected type, unless it is part of a pre/postcondition
6964 -- on another protected operation. This may appear in the entry wrapper
6965 -- created for an entry with preconditions.
6970 and then not In_Spec_Expression
6972 then
6973 Error_Msg_NE
6977 -- Propagate interpretation to actuals, and add default expressions
6978 -- where needed.
6983 -- Overloaded literals are rewritten as function calls, for purpose of
6984 -- resolution. After resolution, we can replace the call with the
6985 -- literal itself.
6991 -- Avoid validation, since it is a static function call
6997 -- If the subprogram is not global, then kill all saved values and
6998 -- checks. This is a bit conservative, since in many cases we could do
6999 -- better, but it is not worth the effort. Similarly, we kill constant
7000 -- values. However we do not need to do this for internal entities
7001 -- (unless they are inherited user-defined subprograms), since they
7002 -- are not in the business of molesting local values.
7004 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
7005 -- kill all checks and values for calls to global subprograms. This
7006 -- takes care of the case where an access to a local subprogram is
7007 -- taken, and could be passed directly or indirectly and then called
7008 -- from almost any context.
7010 -- Note: we do not do this step till after resolving the actuals. That
7011 -- way we still take advantage of the current value information while
7012 -- scanning the actuals.
7014 -- We suppress killing values if we are processing the nodes associated
7015 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
7016 -- type kills all the values as part of analyzing the code that
7017 -- initializes the dispatch tables.
7021 or else Suppress_Value_Tracking_On_Call
7026 then
7027 Kill_Current_Values;
7030 -- If we are warning about unread OUT parameters, this is the place to
7031 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7032 -- after the above call to Kill_Current_Values (since that call clears
7033 -- the Last_Assignment field of all local variables).
7038 then
7039 declare
7043 begin
7053 then
7063 -- If the subprogram is a primitive operation, check whether or not
7064 -- it is a correct dispatching call.
7068 then
7073 and then not In_Instance
7074 then
7078 -- If this is a dispatching call, generate the appropriate reference,
7079 -- for better source navigation in GNAT Studio.
7083 then
7086 -- Normal case, not a dispatching call: generate a call reference
7088 else
7096 -- Check for violation of restriction No_Specific_Termination_Handlers
7097 -- and warn on a potentially blocking call to Abort_Task.
7101 or else
7103 then
7110 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7111 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7112 -- need to check the second argument to determine whether it is an
7113 -- absolute or relative timing event.
7118 then
7122 -- Issue an error for a call to an eliminated subprogram. This routine
7123 -- will not perform the check if the call appears within a default
7124 -- expression.
7128 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7129 -- class-wide and the call dispatches on result in a context that does
7130 -- not provide a tag, the call raises Program_Error.
7133 and then In_Instance
7138 then
7139 -- Verify that none of the formals are controlling
7141 declare
7145 begin
7167 -- Check for calling a function with OUT or IN OUT parameter when the
7168 -- calling context (us right now) is not Ada 2012, so does not allow
7169 -- OUT or IN OUT parameters in function calls. Functions declared in
7170 -- a predefined unit are OK, as they may be called indirectly from a
7171 -- user-declared instantiation.
7177 then
7182 -- Check the dimensions of the actuals in the call. For function calls,
7183 -- propagate the dimensions from the returned type to N.
7187 -- All done, evaluate call and deal with elaboration issues
7195 -- Annotate the tree by creating a call marker in case the original call
7196 -- is transformed by expansion. The call marker is automatically saved
7197 -- for later examination by the ABE Processing phase.
7205 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7206 -- expression function, then we want to "inline" the call, replacing
7207 -- it with the folded static result. This is not done if the checking
7208 -- for a potentially static expression is enabled or if an error has
7209 -- been posted on the call (which may be due to the check for recursive
7210 -- calls, in which case we don't want to fall into infinite recursion
7211 -- when doing the inlining).
7213 if not Checking_Potentially_Static_Expression
7217 then
7220 -- In GNATprove mode, expansion is disabled, but we want to inline some
7221 -- subprograms to facilitate formal verification. Indirect calls through
7222 -- a subprogram type or within a generic cannot be inlined. Inlining is
7223 -- performed only for calls subject to SPARK_Mode on.
7225 elsif GNATprove_Mode
7228 and then not Inside_A_Generic
7229 then
7236 -- Nothing to do if the subprogram is not eligible for inlining in
7237 -- GNATprove mode, or inlining is disabled with switch -gnatdm
7241 or else Debug_Flag_M
7242 then
7245 -- Calls cannot be inlined inside assertions, as GNATprove treats
7246 -- assertions as logic expressions. Only issue a message when the
7247 -- body has been seen, otherwise this leads to spurious messages
7248 -- on expression functions.
7251 Cannot_Inline
7255 -- Calls cannot be inlined inside default expressions
7258 Cannot_Inline
7261 -- Calls cannot be inlined inside quantified expressions, which
7262 -- are left in expression form for GNATprove. Since these
7263 -- expressions are only preanalyzed, we need to detect the failure
7264 -- to inline outside of the case for Full_Analysis below.
7267 Cannot_Inline
7270 -- Inlining should not be performed during preanalysis
7274 -- Do not inline calls inside expression functions or functions
7275 -- generated by the front end for subtype predicates, as this
7276 -- would prevent interpreting them as logical formulas in
7277 -- GNATprove. Only issue a message when the body has been seen,
7278 -- otherwise this leads to spurious messages on callees that
7279 -- are themselves expression functions.
7282 and then
7287 then
7290 then
7292 Cannot_Inline
7297 Cannot_Inline
7302 Cannot_Inline
7306 else
7307 Cannot_Inline
7313 -- Cannot inline a call inside the definition of a record type,
7314 -- typically inside the constraints of the type. Calls in
7315 -- default expressions are also not inlined, but this is
7316 -- filtered out above when testing In_Default_Expr.
7319 Cannot_Inline
7322 -- With the one-pass inlining technique, a call cannot be
7323 -- inlined if the corresponding body has not been seen yet.
7326 Cannot_Inline
7329 -- Nothing to do if there is no body to inline, indicating that
7330 -- the subprogram is not suitable for inlining in GNATprove
7331 -- mode.
7336 -- Calls cannot be inlined inside potentially unevaluated
7337 -- expressions, as this would create complex actions inside
7338 -- expressions, that are not handled by GNATprove.
7341 Cannot_Inline
7345 -- Calls cannot be inlined inside the conditions of while
7346 -- loops, as this would create complex actions inside
7347 -- the condition, that are not handled by GNATprove.
7350 Cannot_Inline
7353 -- Do not inline calls which would possibly lead to missing a
7354 -- type conversion check on an input parameter.
7357 Cannot_Inline
7361 -- Otherwise, inline the call, issuing an info message when
7362 -- -gnatd_f is set.
7364 else
7366 Error_Msg_NE
7377 -----------------------------
7378 -- Resolve_Case_Expression --
7379 -----------------------------
7387 begin
7400 -- When the expression is of a scalar subtype different from the
7401 -- result subtype, then insert a conversion to ensure the generation
7402 -- of a constraint check.
7412 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7413 -- dynamically tagged must be known statically.
7421 Error_Msg_N
7435 -------------------------------
7436 -- Resolve_Character_Literal --
7437 -------------------------------
7443 begin
7444 -- Verify that the character does belong to the type of the context
7449 -- Wide_Wide_Character literals must always be defined, since the set
7450 -- of wide wide character literals is complete, i.e. if a character
7451 -- literal is accepted by the parser, then it is OK for wide wide
7452 -- character (out of range character literals are rejected).
7457 -- Always accept character literal for type Any_Character, which
7458 -- occurs in error situations and in comparisons of literals, both
7459 -- of which should accept all literals.
7464 -- For Standard.Character or a type derived from it, check that the
7465 -- literal is in range.
7472 -- For Standard.Wide_Character or a type derived from it, check that the
7473 -- literal is in range.
7480 -- If the entity is already set, this has already been resolved in a
7481 -- generic context, or comes from expansion. Nothing else to do.
7486 -- Otherwise we have a user defined character type, and we can use the
7487 -- standard visibility mechanisms to locate the referenced entity.
7489 else
7502 -- If we fall through, then the literal does not match any of the
7503 -- entries of the enumeration type. This isn't just a constraint error
7504 -- situation, it is an illegality (see RM 4.2).
7506 Error_Msg_NE
7510 ---------------------------
7511 -- Resolve_Comparison_Op --
7512 ---------------------------
7514 -- The operands must have compatible types and the boolean context does not
7515 -- participate in the resolution. The first pass verifies that the operands
7516 -- are not ambiguous and sets their type correctly, or to Any_Type in case
7517 -- of ambiguity. If both operands are strings or aggregates, then they are
7518 -- ambiguous even if they carry a single (universal) type.
7526 begin
7535 -- Deal with explicit ambiguity of operands
7539 then
7546 -- Deal with other error cases
7550 T = Any_Character
7551 then
7554 else
7562 -- Resolve the operands if types OK
7571 -- Check comparison on unordered enumeration
7575 Error_Msg_NE
7585 --------------------------------
7586 -- Resolve_Declare_Expression --
7587 --------------------------------
7589 procedure Resolve_Declare_Expression
7592 is
7599 -- Use a tree traversal to replace each occurrence of the name of
7600 -- a local object declared in the construct, with the corresponding
7601 -- entity. This replaces the usual way to perform name capture by
7602 -- visibility, because it is not possible to place on the scope
7603 -- stack the fake scope created for the analysis of the local
7604 -- declarations; such a scope conflicts with the transient scopes
7605 -- that may be generated if the expression includes function calls
7606 -- requiring finalization.
7608 -------------------
7609 -- Replace_Local --
7610 -------------------
7613 begin
7614 -- The identifier may be the prefix of a selected component,
7615 -- but not a selector name, because the local entities do not
7616 -- have a scope that can be named: a selected component whose
7617 -- selector is a homonym of a local entity must denote some
7618 -- global entity.
7623 and then
7626 then
7636 -- Start of processing for Resolve_Declare_Expression
7638 begin
7644 N_Object_Declaration | N_Object_Renaming_Declaration
7646 then
7650 -- Traverse the expression to replace references to local
7651 -- variables that occur within declarations of the
7652 -- declare_expression.
7654 declare
7656 begin
7667 -- The end of the declarative list is a freeze point for the
7668 -- local declarations.
7678 -----------------------------------------
7679 -- Resolve_Discrete_Subtype_Indication --
7680 -----------------------------------------
7682 procedure Resolve_Discrete_Subtype_Indication
7685 is
7689 begin
7697 else
7707 Error_Msg_NE
7710 -- Rewrite the constraint as a range of Typ
7711 -- to allow compilation to proceed further.
7723 else
7727 -- Additionally, we must check that the bounds are compatible
7728 -- with the given subtype, which might be different from the
7729 -- type of the context.
7733 -- ??? If the above check statically detects a Constraint_Error
7734 -- it replaces the offending bound(s) of the range R with a
7735 -- Constraint_Error node. When the itype which uses these bounds
7736 -- is frozen the resulting call to Duplicate_Subexpr generates
7737 -- a new temporary for the bounds.
7739 -- Unfortunately there are other itypes that are also made depend
7740 -- on these bounds, so when Duplicate_Subexpr is called they get
7741 -- a forward reference to the newly created temporaries and Gigi
7742 -- aborts on such forward references. This is probably sign of a
7743 -- more fundamental problem somewhere else in either the order of
7744 -- itype freezing or the way certain itypes are constructed.
7746 -- To get around this problem we call Remove_Side_Effects right
7747 -- away if either bounds of R are a Constraint_Error.
7749 declare
7753 begin
7769 -------------------------
7770 -- Resolve_Entity_Name --
7771 -------------------------
7773 -- Used to resolve identifiers and expanded names
7776 function Is_Assignment_Or_Object_Expression
7779 -- Determine whether node Context denotes an assignment statement or an
7780 -- object declaration whose expression is node Expr.
7783 -- Determine whether Expr is part of an N_Attribute_Reference
7784 -- expression.
7786 ----------------------------------------
7787 -- Is_Assignment_Or_Object_Expression --
7788 ----------------------------------------
7790 function Is_Assignment_Or_Object_Expression
7793 is
7794 begin
7797 then
7800 -- Check whether a construct that yields a name is the expression of
7801 -- an assignment statement or an object declaration.
7804 | N_Explicit_Dereference
7805 | N_Indexed_Component
7806 | N_Selected_Component
7807 | N_Slice
7809 or else
7811 | N_Unchecked_Type_Conversion
7813 then
7814 return
7815 Is_Assignment_Or_Object_Expression
7819 -- Otherwise the context is not an assignment statement or an object
7820 -- declaration.
7822 else
7827 -----------------------------
7828 -- Is_Attribute_Expression --
7829 -----------------------------
7833 begin
7838 -- Prevent the search from going too far
7850 -- Local variables
7855 -- Start of processing for Resolve_Entity_Name
7857 begin
7858 -- If garbage from errors, set to Any_Type and return
7865 -- Replace named numbers by corresponding literals. Note that this is
7866 -- the one case where Resolve_Entity_Name must reset the Etype, since
7867 -- it is currently marked as universal.
7877 -- For enumeration literals, we need to make sure that a proper style
7878 -- check is done, since such literals are overloaded, and thus we did
7879 -- not do a style check during the first phase of analysis.
7885 -- Case of (sub)type name appearing in a context where an expression
7886 -- is expected. This is legal if occurrence is a current instance.
7887 -- See RM 8.6 (17/3). It is also legal if the expression is
7888 -- part of a choice pattern for a case stmt/expr having a
7889 -- non-discrete selecting expression.
7895 -- Any other use is an error
7897 else
7898 Error_Msg_N
7902 -- Check discriminant use if entity is discriminant in current scope,
7903 -- i.e. discriminant of record or concurrent type currently being
7904 -- analyzed. Uses in corresponding body are unrestricted.
7909 then
7912 -- A parameterless generic function cannot appear in a context that
7913 -- requires resolution.
7918 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7919 -- array types (i.e. bounds and length) are legal.
7927 or else Is_Assignment_Or_Object_Expression
7930 then
7935 -- In all other cases, just do the possible static evaluation
7937 else
7938 -- A deferred constant that appears in an expression must have a
7939 -- completion, unless it has been removed by in-place expansion of
7940 -- an aggregate. A constant that is a renaming does not need
7941 -- initialization.
7947 and then not In_Spec_Expression
7950 then
7954 then
7956 else
7957 Error_Msg_N
7967 -- When the entity appears in a parameter association, retrieve the
7968 -- related subprogram call.
7976 -- The following checks are only relevant when SPARK_Mode is on as
7977 -- they are not standard Ada legality rules.
7981 -- An effectively volatile object for reading must appear in
7982 -- non-interfering context (SPARK RM 7.1.3(10)).
7986 and then
7988 then
7989 SPARK_Msg_N
7994 -- Check for possible elaboration issues with respect to reads of
7995 -- variables. The act of renaming the variable is not considered a
7996 -- read as it simply establishes an alias.
7998 if Legacy_Elaboration_Checks
8000 and then Dynamic_Elaboration_Checks
8002 then
8007 -- The variable may eventually become a constituent of a single
8008 -- protected/task type. Record the reference now and verify its
8009 -- legality when analyzing the contract of the variable
8010 -- (SPARK RM 9.3).
8016 -- A Ghost entity must appear in a specific context
8023 -- We may be resolving an entity within expanded code, so a reference to
8024 -- an entity should be ignored when calculating effective use clauses to
8025 -- avoid inappropriate marking.
8032 -------------------
8033 -- Resolve_Entry --
8034 -------------------
8046 -- If the bounds of the entry family being called depend on task
8047 -- discriminants, build a new index subtype where a discriminant is
8048 -- replaced with the value of the discriminant of the target task.
8049 -- The target task is the prefix of the entry name in the call.
8051 -----------------------
8052 -- Actual_Index_Type --
8053 -----------------------
8063 -- If the bound is given by a discriminant, replace with a reference
8064 -- to the discriminant of the same name in the target task. If the
8065 -- entry name is the target of a requeue statement and the entry is
8066 -- in the current protected object, the bound to be used is the
8067 -- discriminal of the object (see Apply_Range_Check for details of
8068 -- the transformation).
8070 -----------------------------
8071 -- Actual_Discriminant_Ref --
8072 -----------------------------
8078 begin
8083 then
8089 then
8090 -- Note: here Bound denotes a discriminant of the corresponding
8091 -- record type tskV, whose discriminal is a formal of the
8092 -- init-proc tskVIP. What we want is the body discriminal,
8093 -- which is associated to the discriminant of the original
8094 -- concurrent type tsk.
8096 return New_Occurrence_Of
8099 else
8100 Ref :=
8110 -- Start of processing for Actual_Index_Type
8112 begin
8115 then
8118 else
8132 -- Start of processing for Resolve_Entry
8134 begin
8135 -- Find name of entry being called, and resolve prefix of name with its
8136 -- own type. The prefix can be overloaded, and the name and signature of
8137 -- the entry must be taken into account.
8141 -- Case of dealing with entry family within the current tasks
8145 else
8151 -- Entry call to an entry (or entry family) in the current task. This
8152 -- is legal even though the task will deadlock. Rewrite as call to
8153 -- current task.
8155 -- This can also be a call to an entry in an enclosing task. If this
8156 -- is a single task, we have to retrieve its name, because the scope
8157 -- of the entry is the task type, not the object. If the enclosing
8158 -- task is a task type, the identity of the task is given by its own
8159 -- self variable.
8161 -- Finally this can be a requeue on an entry of the same task or
8162 -- protected object.
8169 then
8170 -- S is an enclosing task or protected object. The concurrent
8171 -- declaration has been converted into a type declaration, and
8172 -- the object itself has an object declaration that follows
8173 -- the type in the same declarative part.
8185 -- Call to current task. Will be transformed into call to Self
8192 New_N :=
8195 Selector_Name =>
8202 then
8203 -- Use the entry name (which must be unique at this point) to find
8204 -- the prefix that returns the corresponding task/protected type.
8206 declare
8212 begin
8234 -- We do not resolve the prefix because an Entry_Family has no type,
8235 -- although it has the semantics of an array since it can be indexed.
8236 -- In order to perform the associated range check, we would need to
8237 -- build an array type on the fly and set it on the prefix, but this
8238 -- would be wasteful since only the index type matters. Therefore we
8239 -- attach this index type directly, so that Actual_Index_Expression
8240 -- can pick it up later in order to generate the range check.
8247 -- Generate a reference for the index when it denotes an entity
8253 -- Up to this point the expression could have been the actual in a
8254 -- simple entry call, and be given by a named association.
8258 else
8264 ------------------------
8265 -- Resolve_Entry_Call --
8266 ------------------------
8277 begin
8278 -- We kill all checks here, because it does not seem worth the effort to
8279 -- do anything better, an entry call is a big operation.
8281 Kill_All_Checks;
8283 -- Processing of the name is similar for entry calls and protected
8284 -- operation calls. Once the entity is determined, we can complete
8285 -- the resolution of the actuals.
8287 -- The selector may be overloaded, in the case of a protected object
8288 -- with overloaded functions. The type of the context is used for
8289 -- resolution.
8294 then
8295 declare
8299 begin
8318 -- Simple entry or protected operation call
8331 -- Call to member of entry family
8338 -- We cannot in general check the maximum depth of protected entry calls
8339 -- at compile time. But we can tell that any protected entry call at all
8340 -- violates a specified nesting depth of zero.
8346 -- Use context type to disambiguate a protected function that can be
8347 -- called without actuals and that returns an array type, and where the
8348 -- argument list may be an indexing of the returned value.
8353 and then
8359 and then
8360 Covers
8363 then
8364 declare
8367 begin
8368 Index_Node :=
8370 Prefix =>
8374 -- Since we are correcting a node classification error made by the
8375 -- parser, we call Replace rather than Rewrite.
8388 then
8389 -- Note the entity being called before rewriting the call, so that
8390 -- it appears used at this point.
8394 -- Rewrite as call to the precondition wrapper, adding the task
8395 -- object to the list of actuals. If the call is to a member of an
8396 -- entry family, include the index as well.
8398 declare
8402 begin
8411 New_Call :=
8413 Name =>
8418 -- Preanalyze and resolve new call. Current procedure is called
8419 -- from Resolve_Call, after which expansion will take place.
8426 -- The operation name may have been overloaded. Order the actuals
8427 -- according to the formals of the resolved entity, and set the return
8428 -- type to that of the operation.
8435 -- Reset the Is_Overloaded flag, since resolution is now completed
8437 -- Simple entry call
8442 -- Call to a member of an entry family
8452 -- Create a call reference to the entry
8460 -- Verify that a procedure call cannot masquerade as an entry
8461 -- call where an entry call is expected.
8466 then
8471 then
8476 then
8481 -- After resolution, entry calls and protected procedure calls are
8482 -- changed into entry calls, for expansion. The structure of the node
8483 -- does not change, so it can safely be done in place. Protected
8484 -- function calls must keep their structure because they are
8485 -- subexpressions.
8489 -- A protected operation that is not a function may modify the
8490 -- corresponding object, and cannot apply to a constant. If this
8491 -- is an internal call, the prefix is the type itself.
8497 then
8498 Error_Msg_N
8500 Entry_Name);
8503 declare
8506 begin
8507 Entry_Call :=
8512 -- Inherit relevant attributes from the original call
8514 Set_First_Named_Actual
8517 Set_Is_Elaboration_Checks_OK_Node
8520 Set_Is_Elaboration_Warnings_OK_Node
8523 Set_Is_SPARK_Mode_On_Node
8530 -- Protected functions can return on the secondary stack, in which case
8531 -- we must trigger the transient scope mechanism.
8533 elsif Expander_Active
8535 then
8539 -- Now we know that this is not a call to a function that returns an
8540 -- array type; moreover, we know the name of the called entry. Detect
8541 -- overlapping actuals, just like for a subprogram call.
8546 -------------------------
8547 -- Resolve_Equality_Op --
8548 -------------------------
8550 -- The operands must have compatible types and the boolean context does not
8551 -- participate in the resolution. The first pass verifies that the operands
8552 -- are not ambiguous and sets their type correctly, or to Any_Type in case
8553 -- of ambiguity. If both operands are strings, aggregates, allocators, or
8554 -- null, they are ambiguous even if they carry a single (universal) type.
8563 -- For any object, '[Unchecked_]Access of such object can never be
8564 -- passed as an operand to the Universal_Access equality operators.
8565 -- This is so because the expected type for Obj'Access in a call to
8566 -- these operators, whose formals are of type Universal_Access, is
8567 -- Universal_Access, and Universal_Access does not have a designated
8568 -- type. For more details, see RM 3.10.2(2/2) and 6.4.1(3).
8571 -- Check RM 4.5.2(9.6/2) on the given designated object types
8574 -- Check RM 4.5.2(9.7/2) on the given designated subprogram types
8577 -- The resolution rule for if expressions requires that each such must
8578 -- have a unique type. This means that if several dependent expressions
8579 -- are of a non-null anonymous access type, and the context does not
8580 -- impose an expected type (as can be the case in an equality operation)
8581 -- the expression must be rejected.
8584 -- Attempt to explain the nature of a redundant comparison with True. If
8585 -- the expression N is too complex, this routine issues a general error
8586 -- message.
8589 -- In the case of allocators and access attributes, the context must
8590 -- provide an indication of the specific access type to be used. If
8591 -- one operand is of such a "generic" access type, check whether there
8592 -- is a specific visible access type that has the same designated type.
8593 -- This is semantically dubious, and of no interest to any real code,
8594 -- but c48008a makes it all worthwhile.
8597 -- Returns True iff the parent node is a and/or/xor operation that
8598 -- could be the cause of confused priorities. Note that if the not is
8599 -- in parens, then False is returned.
8601 ----------------------------
8602 -- Check_Access_Attribute --
8603 ----------------------------
8606 begin
8609 then
8610 Error_Msg_N
8616 -----------------------------------
8617 -- Check_Designated_Object_Types --
8618 -----------------------------------
8621 begin
8625 then
8626 Error_Msg_N
8634 ---------------------------------------
8635 -- Check_Designated_Subprogram_Types --
8636 ---------------------------------------
8639 begin
8641 Error_Msg_N
8649 -------------------------
8650 -- Check_If_Expression --
8651 -------------------------
8657 begin
8664 then
8670 ------------------------
8671 -- Explain_Redundancy --
8672 ------------------------
8679 begin
8682 -- Strip the operand down to an entity
8684 loop
8687 else
8692 -- The construct denotes an entity
8697 -- Do not generate an error message when the comparison is done
8698 -- against the enumeration literal Standard.True.
8702 -- Build a customized error message
8729 -- The construct is too complex to disect, issue a general message
8731 else
8736 -----------------------------
8737 -- Find_Unique_Access_Type --
8738 -----------------------------
8745 begin
8747 then
8751 then
8753 else
8765 then
8778 ----------------------------------
8779 -- Suspicious_Prio_For_Equality --
8780 ----------------------------------
8785 begin
8786 -- Check if parent node is one of and/or/xor, not parenthesized
8787 -- explicitly, and its own parent is not of this kind. Otherwise,
8788 -- it's a case of chained Boolean conditions which is likely well
8789 -- parenthesized.
8794 then
8795 declare
8799 else
8801 begin
8802 -- Compar may have been rewritten, for example from (a /= b)
8803 -- into not (a = b). Use the Original_Node instead.
8807 -- If the other argument of the and/or/xor is also a
8808 -- comparison, or another and/or/xor then most likely
8809 -- the priorities are correctly set.
8814 else
8819 -- Start of processing for Resolve_Equality_Op
8821 begin
8830 -- Deal with explicit ambiguity of operands
8834 then
8838 else
8839 -- Deal with other error cases
8843 T = Any_Character
8844 then
8847 else
8856 then
8865 -- If expressions must have a single type, and if the context does
8866 -- not impose one the dependent expressions cannot be anonymous
8867 -- access types.
8869 -- Why no similar processing for case expressions???
8874 then
8879 -- RM 4.5.2(9.5/2): At least one of the operands of the equality
8880 -- operators for universal_access shall be of type universal_access,
8881 -- or both shall be of access-to-object types, or both shall be of
8882 -- access-to-subprogram types (RM 4.5.2(9.5/2)).
8887 then
8888 -- RM 4.5.2(9.6/2): When both are of access-to-object types, the
8889 -- designated types shall be the same or one shall cover the other
8890 -- and if the designated types are elementary or array types, then
8891 -- the designated subtypes shall statically match.
8895 then
8896 Check_Designated_Object_Types
8899 -- RM 4.5.2(9.7/2): When both are of access-to-subprogram types,
8900 -- the designated profiles shall be subtype conformant.
8904 then
8905 Check_Designated_Subprogram_Types
8910 -- Check another case of equality operators for universal_access
8920 -- If the unique type is a class-wide type then it will be expanded
8921 -- into a dispatching call to the predefined primitive. Therefore we
8922 -- check here for potential violation of such restriction.
8928 -- Only warn for redundant equality comparison to True for objects
8929 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8930 -- other expressions, it may be a matter of preference to write
8931 -- "Expr = True" or "Expr".
8933 if Warn_On_Redundant_Constructs
8938 and then
8940 or else
8942 then
8943 Error_Msg_N -- CODEFIX
8948 -- Warn on a (in)equality between boolean values which is not
8949 -- parenthesized when the parent expression is one of and/or/xor, as
8950 -- this is interpreted as (a = b) op c where most likely a = (b op c)
8951 -- was intended. Do not generate a warning in generic instances, as
8952 -- the problematic expression may be implicitly parenthesized in
8953 -- the generic itself if one of the operators is a generic formal.
8954 -- Also do not generate a warning for generated equality, for
8955 -- example from rewritting a membership test.
8957 if Warn_On_Questionable_Missing_Parens
8958 and then not In_Instance
8961 and then Suspicious_Prio_For_Equality
8962 then
8971 -- If this is an inequality, it may be the implicit inequality
8972 -- created for a user-defined operation, in which case the corres-
8973 -- ponding equality operation is not intrinsic, and the operation
8974 -- cannot be constant-folded. Else fold.
8979 or else Is_Intrinsic_Subprogram
8981 then
8987 then
8993 ----------------------------------
8994 -- Resolve_Explicit_Dereference --
8995 ----------------------------------
9003 -- The candidate prefix type, if overloaded
9008 begin
9012 -- A useful optimization: check whether the dereference denotes an
9013 -- element of a container, and if so rewrite it as a call to the
9014 -- corresponding Element function.
9016 -- Disabled for now, on advice of ARG. A more restricted form of the
9017 -- predicate might be acceptable ???
9019 -- if Is_Container_Element (N) then
9020 -- return;
9021 -- end if;
9025 -- Use the context type to select the prefix that has the correct
9026 -- designated type. Keep the first match, which will be the inner-
9027 -- most.
9034 then
9039 -- Remove access types that do not match, but preserve access
9040 -- to subprogram interpretations, in case a further dereference
9041 -- is needed (see below).
9054 else
9055 -- If no interpretation covers the designated type of the prefix,
9056 -- this is the pathological case where not all implementations of
9057 -- the prefix allow the interpretation of the node as a call. Now
9058 -- that the expected type is known, Remove other interpretations
9059 -- from prefix, rewrite it as a call, and resolve again, so that
9060 -- the proper call node is generated.
9071 New_N :=
9073 Name =>
9084 -- If not overloaded, resolve P with its own type
9086 else
9090 -- If the prefix might be null, add an access check
9094 then
9098 -- If the designated type is a packed unconstrained array type, and the
9099 -- explicit dereference is not in the context of an attribute reference,
9100 -- then we must compute and set the actual subtype, since it is needed
9101 -- by Gigi. The reason we exclude the attribute case is that this is
9102 -- handled fine by Gigi, and in fact we use such attributes to build the
9103 -- actual subtype. We also exclude generated code (which builds actual
9104 -- subtypes directly if they are needed).
9110 then
9116 -- Note: No Eval processing is required for an explicit dereference,
9117 -- because such a name can never be static.
9121 -------------------------------------
9122 -- Resolve_Expression_With_Actions --
9123 -------------------------------------
9128 -- True if Act is an action of a declare_expression that is allowed in a
9129 -- static declare_expression.
9132 -- True if all actions of N are allowed in a static declare_expression.
9135 -- Expr is an expression with compile-time-known value. This returns the
9136 -- literal node that reprsents that value.
9139 begin
9144 then
9154 -- No other declarations, nor even pragmas, are allowed in a
9155 -- declare expression, so if we see something else, it must be
9156 -- an internally generated expression_with_actions.
9165 begin
9180 begin
9185 else
9194 pragma Assert
9202 begin
9209 -- If the value of the expression is known at compile time, and all
9210 -- of the actions (if any) are suitable, then replace the declare
9211 -- expression with its expression. This allows the declare expression
9212 -- as a whole to be static if appropriate. See AI12-0368.
9218 Rewrite
9225 ----------------------------------
9226 -- Resolve_Generalized_Indexing --
9227 ----------------------------------
9231 begin
9236 ---------------------------
9237 -- Resolve_If_Expression --
9238 ---------------------------
9242 -- When a dependent expression is of a subtype different from
9243 -- the context subtype, then insert a qualification to ensure
9244 -- the generation of a constraint check. This was previously
9245 -- for scalar types. For array types apply a length check, given
9246 -- that the context in general allows sliding, while a qualified
9247 -- expression forces equality of bounds.
9250 -- So in most cases the type of the If_Expression and of its
9251 -- dependent expressions is that of the context. However, if
9252 -- the expression is the index of an Indexed_Component, we must
9253 -- ensure that a proper index check is applied, rather than a
9254 -- range check on the index type (which might be discriminant
9255 -- dependent). In this case we resolve with the base type of the
9256 -- index type, and the index check is generated in the resolution
9257 -- of the indexed_component above.
9259 -----------------
9260 -- Apply_Check --
9261 -----------------
9267 begin
9272 or else Inside_A_Generic
9273 then
9279 else
9289 -- Local variables
9295 -- Start of processing for Resolve_If_Expression
9297 begin
9298 -- Defend against malformed expressions
9307 then
9326 -- If ELSE expression present, just resolve using the determined type
9327 -- If type is universal, resolve to any member of the class.
9336 else
9344 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9345 -- dynamically tagged must be known statically.
9350 then
9356 -- If no ELSE expression is present, root type must be Standard.Boolean
9357 -- and we provide a Standard.True result converted to the appropriate
9358 -- Boolean type (in case it is a derived boolean type).
9361 Else_Expr :=
9366 else
9380 ----------------------------------
9381 -- Resolve_Implicit_Dereference --
9382 ----------------------------------
9387 begin
9388 -- In an instance the proper view may not always be correct for
9389 -- private types, see e.g. Sem_Type.Covers for similar handling.
9394 and then In_Instance
9395 then
9406 -------------------------------
9407 -- Resolve_Indexed_Component --
9408 -------------------------------
9416 begin
9424 -- Use the context type to select the prefix that yields the correct
9425 -- component type.
9427 declare
9433 begin
9440 and then
9441 Covers
9444 then
9453 else
9459 else
9470 else
9477 -- If the prefix's type is an access type, get to the real array type.
9478 -- Note: we do not apply an access check because an explicit dereference
9479 -- will be introduced later, and the check will happen there.
9485 -- If name was overloaded, set component type correctly now.
9486 -- If a misplaced call to an entry family (which has no index types)
9487 -- return. Error will be diagnosed from calling context.
9491 else
9498 -- The prefix may have resolved to a string literal, in which case its
9499 -- etype has a special representation. This is only possible currently
9500 -- if the prefix is a static concatenation, written in functional
9501 -- notation.
9506 else
9521 -- Do not generate the warning on suspicious index if we are analyzing
9522 -- package Ada.Tags; otherwise we will report the warning with the
9523 -- Prims_Ptr field of the dispatch table.
9526 or else not
9528 then
9533 -- If the array type is atomic and the component is not, then this is
9534 -- worth a warning before Ada 2022, since we have a situation where the
9535 -- access to the component may cause extra read/writes of the atomic
9536 -- object, or partial word accesses, both of which may be unexpected.
9542 and then Has_Atomic_Components
9546 then
9547 Error_Msg_N
9549 Error_Msg_N
9554 -----------------------------
9555 -- Resolve_Integer_Literal --
9556 -----------------------------
9559 begin
9564 --------------------------------
9565 -- Resolve_Intrinsic_Operator --
9566 --------------------------------
9575 -- If the operand is a literal, it cannot be the expression in a
9576 -- conversion. Use a qualified expression instead.
9578 ---------------------
9579 -- Convert_Operand --
9580 ---------------------
9586 begin
9588 Res :=
9594 else
9601 -- Start of processing for Resolve_Intrinsic_Operator
9603 begin
9604 -- We must preserve the original entity in a generic setting, so that
9605 -- the legality of the operation can be verified in an instance.
9620 -- If the result or operand types are private, rewrite with unchecked
9621 -- conversions on the operands and the result, to expose the proper
9622 -- underlying numeric type.
9627 then
9632 else
9653 then
9654 -- Add explicit conversion where needed, and save interpretations in
9655 -- case operands are overloaded.
9662 else
9668 else
9678 else
9683 --------------------------------------
9684 -- Resolve_Intrinsic_Unary_Operator --
9685 --------------------------------------
9687 procedure Resolve_Intrinsic_Unary_Operator
9690 is
9695 begin
9714 else
9719 ------------------------
9720 -- Resolve_Logical_Op --
9721 ------------------------
9726 begin
9729 -- Predefined operations on scalar types yield the base type. On the
9730 -- other hand, logical operations on arrays yield the type of the
9731 -- arguments (and the context).
9735 else
9739 -- The following test is required because the operands of the operation
9740 -- may be literals, in which case the resulting type appears to be
9741 -- compatible with a signed integer type, when in fact it is compatible
9742 -- only with modular types. If the context itself is universal, the
9743 -- operation is illegal.
9751 Error_Msg_N
9759 then
9763 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
9764 -- is active and the result type is standard Boolean (do not mess with
9765 -- ops that return a nonstandard Boolean type, because something strange
9766 -- is going on).
9768 -- Note: you might expect this replacement to be done during expansion,
9769 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
9770 -- is used, no part of the right operand of an "and" or "or" operator
9771 -- should be executed if the left operand would short-circuit the
9772 -- evaluation of the corresponding "and then" or "or else". If we left
9773 -- the replacement to expansion time, then run-time checks associated
9774 -- with such operands would be evaluated unconditionally, due to being
9775 -- before the condition prior to the rewriting as short-circuit forms
9776 -- during expansion.
9778 if Short_Circuit_And_Or
9781 then
9782 -- Mark the corresponding putative SCO operator as truly a logical
9783 -- (and short-circuit) operator.
9796 -- Case of OR changed to OR ELSE
9798 else
9806 -- Return now, since analysis of the rewritten ops will take care of
9807 -- other reference bookkeeping and expression folding.
9823 ---------------------------
9824 -- Resolve_Membership_Op --
9825 ---------------------------
9827 -- The context can only be a boolean type, and does not determine the
9828 -- arguments. Arguments should be unambiguous, but the preference rule for
9829 -- universal types applies.
9839 -- Analysis has determined a unique type for the left operand. Use it as
9840 -- the basis to resolve the disjuncts.
9842 ----------------------------
9843 -- Resolve_Set_Membership --
9844 ----------------------------
9849 begin
9850 -- If the left operand is overloaded, find type compatible with not
9851 -- overloaded alternative of the right operand.
9860 else
9865 -- Unclear how to resolve expression if all alternatives are also
9866 -- overloaded.
9872 else
9881 -- Alternative is an expression, a range
9882 -- or a subtype mark.
9886 then
9893 -- Check for duplicates for discrete case
9896 declare
9905 begin
9906 -- Loop checking duplicates. This is quadratic, but giant sets
9907 -- are unlikely in this context so it's a reasonable choice.
9914 | N_Character_Literal
9915 | N_Has_Entity
9916 then
9933 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
9934 -- limited types, evaluation of a membership test uses the predefined
9935 -- equality for the type. This may be confusing to users, and the
9936 -- following warning appears useful for the most common case.
9940 then
9941 Error_Msg_NE
9943 Error_Msg_N
9948 -- Start of processing for Resolve_Membership_Op
9950 begin
9956 Resolve_Set_Membership;
9962 then
9965 -- Ada 2005 (AI-251): Support the following case:
9967 -- type I is interface;
9968 -- type T is tagged ...
9970 -- function Test (O : I'Class) is
9971 -- begin
9972 -- return O in T'Class.
9973 -- end Test;
9975 -- In this case we have nothing else to do. The membership test will be
9976 -- done at run time.
9982 then
9984 else
9988 -- If mixed-mode operations are present and operands are all literal,
9989 -- the only interpretation involves Duration, which is probably not
9990 -- the intention of the programmer.
10005 then
10011 else
10016 -- Here after resolving membership operation
10023 ------------------
10024 -- Resolve_Null --
10025 ------------------
10030 begin
10031 -- Handle restriction against anonymous null access values This
10032 -- restriction can be turned off using -gnatdj.
10034 -- Ada 2005 (AI-231): Remove restriction
10037 and then not Debug_Flag_J
10040 then
10041 -- In the common case of a call which uses an explicitly null value
10042 -- for an access parameter, give specialized error message.
10045 Error_Msg_N
10048 -- Standard message for all other cases (are there any?)
10050 else
10051 Error_Msg_N
10056 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
10057 -- assignment to a null-excluding object.
10062 then
10065 -- Decide whether to generate an if_statement around our
10066 -- null-excluding check to avoid them on certain internal object
10067 -- declarations by looking at the type the current Init_Proc
10068 -- belongs to.
10070 -- Generate:
10071 -- if T1b_skip_null_excluding_check then
10072 -- [constraint_error "access check failed"]
10073 -- end if;
10075 if Needs_Conditional_Null_Excluding_Check
10077 then
10080 Condition =>
10082 New_External_Name
10084 Then_Statements =>
10085 New_List (
10089 -- Otherwise, simply create the check
10091 else
10096 else
10097 Insert_Action
10105 -- In a distributed context, null for a remote access to subprogram may
10106 -- need to be replaced with a special record aggregate. In this case,
10107 -- return after having done the transformation.
10112 then
10116 -- The null literal takes its type from the context
10121 -----------------------
10122 -- Resolve_Op_Concat --
10123 -----------------------
10127 -- We wish to avoid deep recursion, because concatenations are often
10128 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10129 -- operands nonrecursively until we find something that is not a simple
10130 -- concatenation (A in this case). We resolve that, and then walk back
10131 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10132 -- to do the rest of the work at each level. The Parent pointers allow
10133 -- us to avoid recursion, and thus avoid running out of memory. See also
10134 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10139 begin
10140 -- The following code is equivalent to:
10142 -- Resolve_Op_Concat_First (NN, Typ);
10143 -- Resolve_Op_Concat_Arg (N, ...);
10144 -- Resolve_Op_Concat_Rest (N, Typ);
10146 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10147 -- operand is a concatenation.
10149 -- Walk down left operands
10151 loop
10160 -- Now (given the above example) NN is A&B and Op1 is A
10162 -- First resolve Op1 ...
10166 -- ... then walk NN back up until we reach N (where we started), calling
10167 -- Resolve_Op_Concat_Rest along the way.
10169 loop
10176 ---------------------------
10177 -- Resolve_Op_Concat_Arg --
10178 ---------------------------
10180 procedure Resolve_Op_Concat_Arg
10185 is
10189 begin
10191 if Is_Comp
10195 then
10197 else
10201 -- If both Array & Array and Array & Component are visible, there is a
10202 -- potential ambiguity that must be reported.
10207 then
10211 -- If the operation is user-defined and not overloaded use its
10212 -- profile. The operation may be a renaming, in which case it has
10213 -- been rewritten, and we want the original profile.
10218 then
10220 Etype
10224 -- Otherwise an aggregate may match both the array type and the
10225 -- component type.
10227 else
10232 else
10236 then
10237 declare
10242 begin
10247 -- Special-case the error message when the overloading is
10248 -- caused by a function that yields an array and can be
10249 -- called without parameters.
10254 Error_Msg_NE
10256 Error_Msg_NE
10260 else
10268 or else
10270 then
10271 Error_Msg_N -- CODEFIX
10288 then
10289 -- Determine if the out-of-range violation constitutes a
10290 -- warning or an error according to the expression base type,
10291 -- according to Ada 2022 RM 4.9 (35/2).
10294 Apply_Compile_Time_Constraint_Error
10300 Apply_Compile_Time_Constraint_Error
10309 else
10314 else
10321 -----------------------------
10322 -- Resolve_Op_Concat_First --
10323 -----------------------------
10330 begin
10331 -- The parser folds an enormous sequence of concatenations of string
10332 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10333 -- in the right operand. If the expression resolves to a predefined "&"
10334 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10335 -- we give an error. See P_Simple_Expression in Par.Ch4.
10340 then
10355 ----------------------------
10356 -- Resolve_Op_Concat_Rest --
10357 ----------------------------
10363 begin
10372 -- If this is not a static concatenation, but the result is a string
10373 -- type (and not an array of strings) ensure that static string operands
10374 -- have their subtypes properly constructed.
10378 then
10384 ----------------------
10385 -- Resolve_Op_Expon --
10386 ----------------------
10391 begin
10392 -- Catch attempts to do fixed-point exponentiation with universal
10393 -- operands, which is a case where the illegality is not caught during
10394 -- normal operator analysis. This is not done in preanalysis mode
10395 -- since the tree is not fully decorated during preanalysis.
10407 then
10417 then
10426 -- We do the resolution using the base type, because intermediate values
10427 -- in expressions are always of the base type, not a subtype of it.
10432 -- For integer types, right argument must be in Natural range
10447 -- Evaluate the exponentiation operator for dimensioned type
10450 else
10454 -- Set overflow checking bit. Much cleverer code needed here eventually
10455 -- and perhaps the Resolve routines should be separated for the various
10456 -- arithmetic operations, since they will need different processing. ???
10465 --------------------
10466 -- Resolve_Op_Not --
10467 --------------------
10471 -- This function determines if the parent node is a boolean operator or
10472 -- operation (comparison op, membership test, or short circuit form) and
10473 -- the not in question is the left operand of this operation. Note that
10474 -- if the not is in parens, then false is returned.
10476 -----------------------
10477 -- Parent_Is_Boolean --
10478 -----------------------
10481 begin
10484 | N_Op_Boolean
10485 | N_Short_Circuit
10489 -- Local variables
10493 -- Start of processing for Resolve_Op_Not
10495 begin
10496 -- Predefined operations on scalar types yield the base type. On the
10497 -- other hand, logical operations on arrays yield the type of the
10498 -- arguments (and the context).
10502 else
10506 -- Straightforward case of incorrect arguments
10513 -- Special case of probable missing parens
10517 Error_Msg_N
10520 else
10521 Error_Msg_N
10528 -- OK resolution of NOT
10530 else
10531 -- Warn if non-boolean types involved. This is a case like not a < b
10532 -- where a and b are modular, where we will get (not a) < b and most
10533 -- likely not (a < b) was intended.
10535 if Warn_On_Questionable_Missing_Parens
10537 and then Parent_Is_Boolean
10538 then
10542 -- Warn on double negation if checking redundant constructs
10544 if Warn_On_Redundant_Constructs
10549 then
10553 -- Complete resolution and evaluation of NOT
10563 -----------------------------
10564 -- Resolve_Operator_Symbol --
10565 -----------------------------
10567 -- Nothing to be done, all resolved already
10573 begin
10577 ----------------------------------
10578 -- Resolve_Qualified_Expression --
10579 ----------------------------------
10587 begin
10590 -- A qualified expression requires an exact match of the type, class-
10591 -- wide matching is not allowed. However, if the qualifying type is
10592 -- specific and the expression has a class-wide type, it may still be
10593 -- okay, since it can be the result of the expansion of a call to a
10594 -- dispatching function, so we also have to check class-wideness of the
10595 -- type of the expression's original node.
10598 or else
10602 then
10606 -- If the target type is unconstrained, then we reset the type of the
10607 -- result from the type of the expression. For other cases, the actual
10608 -- subtype of the expression is the target type. But we avoid doing it
10609 -- for an allocator since this is not needed and might be problematic.
10614 then
10621 -- If we still have a qualified expression after the static evaluation,
10622 -- then apply a scalar range check if needed. The reason that we do this
10623 -- after the Eval call is that otherwise, the application of the range
10624 -- check may convert an illegal static expression and result in warning
10625 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
10629 then
10633 -- AI12-0100: Once the qualified expression is resolved, check whether
10634 -- operand satisfies a static predicate of the target subtype, if any.
10635 -- In the static expression case, a predicate check failure is an error.
10638 Check_Expression_Against_Static_Predicate
10643 ------------------------------
10644 -- Resolve_Raise_Expression --
10645 ------------------------------
10648 begin
10653 else
10656 -- Apply check for required parentheses in the enclosing
10657 -- context of raise_expressions (RM 11.3 (2)), including default
10658 -- expressions in contexts that can include aspect specifications,
10659 -- and ancestor parts of extension aggregates.
10661 declare
10665 begin
10668 loop
10675 then
10682 if not Parentheses_Found
10684 and then
10686 | N_Floating_Point_Definition
10687 | N_Ordinary_Fixed_Point_Definition
10688 | N_Decimal_Fixed_Point_Definition
10689 | N_Extension_Aggregate
10690 | N_Discriminant_Specification
10691 | N_Parameter_Specification
10692 | N_Formal_Object_Declaration)
10695 and then
10697 then
10698 Error_Msg_N
10700 N);
10706 -------------------
10707 -- Resolve_Range --
10708 -------------------
10715 -- Returns True if N is of the form X'First .. X'Last where X is the
10716 -- same entity for both attributes.
10718 --------------------
10719 -- First_Last_Ref --
10720 --------------------
10726 begin
10731 then
10732 declare
10735 begin
10745 -- Start of processing for Resolve_Range
10747 begin
10753 -- Reanalyze the lower bound after both bounds have been analyzed, so
10754 -- that the range is known to be static or not by now. This may trigger
10755 -- more compile-time evaluation, which is useful for static analysis
10756 -- with GNATprove. This is not needed for compilation or static analysis
10757 -- with CodePeer, as full expansion does that evaluation then.
10764 -- Check for inappropriate range on unordered enumeration type
10768 -- Exclude X'First .. X'Last if X is the same entity for both
10770 and then not First_Last_Ref
10771 then
10773 Error_Msg_NE
10780 -- We have to check the bounds for being within the base range as
10781 -- required for a non-static context. Normally this is automatic and
10782 -- done as part of evaluating expressions, but the N_Range node is an
10783 -- exception, since in GNAT we consider this node to be a subexpression,
10784 -- even though in Ada it is not. The circuit in Sem_Eval could check for
10785 -- this, but that would put the test on the main evaluation path for
10786 -- expressions.
10791 -- Check for an ambiguous range over character literals. This will
10792 -- happen with a membership test involving only literals.
10800 -- If bounds are static, constant-fold them, so size computations are
10801 -- identical between front-end and back-end. Do not perform this
10802 -- transformation while analyzing generic units, as type information
10803 -- would be lost when reanalyzing the constant node in the instance.
10815 -- If we have a compile-time-known null range, we warn, because that is
10816 -- likely to be a mistake. (Dynamic null ranges make sense, but often
10817 -- compile-time-known ones do not.) Warn only if this is in a subtype
10818 -- declaration. We do this here, rather than while analyzing a subtype
10819 -- declaration, in case we decide to expand the cases. We do not want to
10820 -- warn in all cases, because some are idiomatic, such as an empty
10821 -- aggregate (1 .. 0 => <>).
10823 -- We don't warn in generics or their instances, because there might be
10824 -- some instances where the range is null, and some where it is not,
10825 -- which would lead to false alarms.
10829 and then Compile_Time_Compare
10835 then
10840 --------------------------
10841 -- Resolve_Real_Literal --
10842 --------------------------
10847 begin
10848 -- Special processing for fixed-point literals to make sure that the
10849 -- value is an exact multiple of the small where this is required. We
10850 -- skip this for the universal real case, and also for generic types.
10856 then
10857 -- We must freeze the base type to get the proper value of the small
10863 declare
10870 begin
10871 -- Case of literal is not an exact multiple of the Small
10875 -- For a source program literal for a decimal fixed-point type,
10876 -- this is statically illegal (RM 4.9(36)).
10881 then
10885 -- Generate a warning if literal from source
10888 and then Warn_On_Bad_Fixed_Value
10889 then
10890 Error_Msg_N
10892 N);
10895 -- Replace literal by a value that is the exact representation
10896 -- of a value of the type, i.e. a multiple of the small value,
10897 -- by truncation, since Machine_Rounds is false for all GNAT
10898 -- fixed-point types (RM 4.9(38)).
10908 -- In all cases, set the corresponding integer field
10914 -- Now replace the actual type by the expected type as usual
10920 -----------------------
10921 -- Resolve_Reference --
10922 -----------------------
10927 begin
10928 -- Replace general access with specific type
10936 -- If we are taking the reference of a volatile entity, then treat it as
10937 -- a potential modification of this entity. This is too conservative,
10938 -- but necessary because remove side effects can cause transformations
10939 -- of normal assignments into reference sequences that otherwise fail to
10940 -- notice the modification.
10947 --------------------------------
10948 -- Resolve_Selected_Component --
10949 --------------------------------
10964 -- Check whether this is the initialization of a component within an
10965 -- init proc (by assignment or call to another init proc). If true,
10966 -- there is no need for a discriminant check.
10968 --------------------
10969 -- Init_Component --
10970 --------------------
10973 begin
10974 return Inside_Init_Proc
10980 -- Start of processing for Resolve_Selected_Component
10982 begin
10985 -- Use the context type to select the prefix that has a selector
10986 -- of the correct name and type.
10994 else
10998 -- Locate selected component. For a private prefix the selector
10999 -- can denote a discriminant.
11003 -- The visible components of a class-wide type are those of
11004 -- the root type.
11014 then
11021 else
11025 Error_Msg_N
11030 else
11033 -- There may be an implicit dereference. Retrieve
11034 -- designated record type.
11038 else
11044 -- Resolution chooses the new interpretation.
11045 -- Find the component with the right name.
11050 loop
11067 -- There must be a legal interpretation at this point
11072 -- In general the expected type is the type of the context, not the
11073 -- type of the candidate selected component.
11078 -- The type of the context and that of the component are
11079 -- compatible and in general identical, but if they are anonymous
11080 -- access-to-subprogram types, the relevant type is that of the
11081 -- component. This matters in Unnest_Subprograms mode, where the
11082 -- relevant context is the one in which the type is declared, not
11083 -- the point of use. This determines what activation record to use.
11088 -- When the type of the component is an access to a class-wide type
11089 -- the relevant type is that of the component (since in such case we
11090 -- may need to generate implicit type conversions or dispatching
11091 -- calls).
11096 then
11100 else
11101 -- Resolve prefix with its type
11106 -- Generate cross-reference. We needed to wait until full overloading
11107 -- resolution was complete to do this, since otherwise we can't tell if
11108 -- we are an lvalue or not.
11112 else
11116 -- If the prefix's type is an access type, get to the real record type.
11117 -- Note: we do not apply an access check because an explicit dereference
11118 -- will be introduced later, and the check will happen there.
11124 else
11127 -- If the prefix is an entity it may have a deferred reference set
11128 -- during analysis of the selected component. After resolution we
11129 -- can transform it into a proper reference. This prevents spurious
11130 -- warnings on useless assignments when the same selected component
11131 -- is the actual for an out parameter in a subsequent call.
11135 then
11138 else
11144 -- Set flag for expander if discriminant check required on a component
11145 -- appearing within a variant.
11151 and then
11154 and then not Init_Component
11155 then
11163 -- If the prefix is a record conversion, this may be a renamed
11164 -- discriminant whose bounds differ from those of the original
11165 -- one, so we must ensure that a range check is performed.
11170 then
11174 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11180 -- If the record type is atomic and the component is not, then this
11181 -- is worth a warning before Ada 2022, since we have a situation
11182 -- where the access to the component may cause extra read/writes of
11183 -- the atomic object, or partial word accesses, both of which may be
11184 -- unexpected.
11190 then
11191 Error_Msg_N
11194 Error_Msg_N
11204 -------------------
11205 -- Resolve_Shift --
11206 -------------------
11213 begin
11214 -- We do the resolution using the base type, because intermediate values
11215 -- in expressions always are of the base type, not a subtype of it.
11228 ---------------------------
11229 -- Resolve_Short_Circuit --
11230 ---------------------------
11237 begin
11238 -- Ensure all actions associated with the left operand (e.g.
11239 -- finalization of transient objects) are fully evaluated locally within
11240 -- an expression with actions. This is particularly helpful for coverage
11241 -- analysis. However this should not happen in generics or if option
11242 -- Minimize_Expression_With_Actions is set.
11245 declare
11247 begin
11255 -- Set Comes_From_Source on L to preserve warnings for unset
11256 -- reference.
11265 -- Check for issuing warning for always False assert/check, this happens
11266 -- when assertions are turned off, in which case the pragma Assert/Check
11267 -- was transformed into:
11269 -- if False and then <condition> then ...
11271 -- and we detect this pattern
11273 if Warn_On_Assertion_Failure
11280 then
11281 declare
11284 begin
11285 -- Special handling of Asssert pragma
11289 then
11290 declare
11292 Original_Node
11293 (Expression
11296 begin
11297 -- Don't warn if original condition is explicit False,
11298 -- since obviously the failure is expected in this case.
11302 then
11305 -- Issue warning. We do not want the deletion of the
11306 -- IF/AND-THEN to take this message with it. We achieve this
11307 -- by making sure that the expanded code points to the Sloc
11308 -- of the expression, not the original pragma.
11310 else
11311 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11312 -- The source location of the expression is not usually
11313 -- the best choice here. For example, it gets located on
11314 -- the last AND keyword in a chain of boolean expressiond
11315 -- AND'ed together. It is best to put the message on the
11316 -- first character of the assertion, which is the effect
11317 -- of the First_Node call here.
11319 Error_Msg_F
11321 Expression
11326 -- Similar processing for Check pragma
11330 then
11331 -- Don't want to warn if original condition is explicit False
11333 declare
11335 Original_Node
11336 (Expression
11338 begin
11341 then
11344 -- Post warning
11346 else
11347 -- Again use Error_Msg_F rather than Error_Msg_N, see
11348 -- comment above for an explanation of why we do this.
11350 Error_Msg_F
11352 Expression
11360 -- Continue with processing of short circuit
11369 -------------------
11370 -- Resolve_Slice --
11371 -------------------
11380 begin
11383 -- Use the context type to select the prefix that yields the correct
11384 -- array type.
11386 declare
11392 begin
11400 then
11408 else
11413 else
11424 else
11430 -- If the prefix's type is an access type, get to the real array type.
11431 -- Note: we do not apply an access check because an explicit dereference
11432 -- will be introduced later, and the check will happen there.
11437 -- If the prefix is an access to an unconstrained array, we must use
11438 -- the actual subtype of the object to perform the index checks. The
11439 -- object denoted by the prefix is implicit in the node, so we build
11440 -- an explicit representation for it in order to compute the actual
11441 -- subtype.
11446 declare
11450 begin
11457 -- In CodePeer mode the attribute Image is not expanded, so when it
11458 -- acts as a prefix of a slice, we handle it like a call to function
11459 -- returning an unconstrained string. Same for the Wide variants of
11460 -- attribute Image.
11469 | Name_Wide_Image
11470 | Name_Wide_Wide_Image)
11471 then
11474 -- If the name is a selected component that depends on discriminants,
11475 -- build an actual subtype for it. This can happen only when the name
11476 -- itself is overloaded; otherwise the actual subtype is created when
11477 -- the selected component is analyzed.
11480 and then Full_Analysis
11482 then
11483 declare
11486 begin
11491 -- Maybe this should just be "else", instead of checking for the
11492 -- specific case of slice??? This is needed for the case where the
11493 -- prefix is an Image attribute, which gets expanded to a slice, and so
11494 -- has a constrained subtype which we want to use for the slice range
11495 -- check applied below (the range check won't get done if the
11496 -- unconstrained subtype of the 'Image is used).
11502 -- Obtain the type of the array index
11506 else
11510 -- If name was overloaded, set slice type correctly now
11514 -- Handle the generation of a range check that compares the array index
11515 -- against the discrete_range. The check is not applied to internally
11516 -- built nodes associated with the expansion of dispatch tables. Check
11517 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11518 -- the unit.
11520 if Tagged_Type_Expansion
11526 then
11529 -- The discrete_range is specified by a subtype name. Create an
11530 -- equivalent range attribute, apply checks to this attribute, but
11531 -- insert them into the range expression of the slice itself.
11534 Dexpr :=
11535 Make_Attribute_Reference
11537 Prefix =>
11546 -- The discrete_range is a regular range (or a range attribute, which
11547 -- will be resolved into a regular range). Resolve the bounds and remove
11548 -- their side effects.
11550 else
11567 -- Check bad use of type with predicates
11569 declare
11572 begin
11575 then
11577 else
11582 Bad_Predicated_Subtype_Use
11587 -- Otherwise here is where we check suspicious indexes
11599 ----------------------------
11600 -- Resolve_String_Literal --
11601 ----------------------------
11612 begin
11613 -- For a string appearing in a concatenation, defer creation of the
11614 -- string_literal_subtype until the end of the resolution of the
11615 -- concatenation, because the literal may be constant-folded away. This
11616 -- is a useful optimization for long concatenation expressions.
11618 -- If the string is an aggregate built for a single character (which
11619 -- happens in a non-static context) or a is null string to which special
11620 -- checks may apply, we build the subtype. Wide strings must also get a
11621 -- string subtype if they come from a one character aggregate. Strings
11622 -- generated by attributes might be static, but it is often hard to
11623 -- determine whether the enclosing context is static, so we generate
11624 -- subtypes for them as well, thus losing some rarer optimizations ???
11625 -- Same for strings that come from a static conversion.
11627 Need_Check :=
11636 -- If the resolving type is itself a string literal subtype, we can just
11637 -- reuse it, since there is no point in creating another.
11643 and then not Need_Check
11645 | N_Attribute_Reference
11646 | N_Qualified_Expression
11647 | N_Type_Conversion
11648 then
11651 -- Do not generate a string literal subtype for the default expression
11652 -- of a formal parameter in GNATprove mode. This is because the string
11653 -- subtype is associated with the freezing actions of the subprogram,
11654 -- however freezing is disabled in GNATprove mode and as a result the
11655 -- subtype is unavailable.
11657 elsif GNATprove_Mode
11659 then
11662 -- Otherwise we must create a string literal subtype. Note that the
11663 -- whole idea of string literal subtypes is simply to avoid the need
11664 -- for building a full fledged array subtype for each literal.
11666 else
11672 or else Need_Check
11673 then
11680 then
11686 -- The validity of a null string has been checked in the call to
11687 -- Eval_String_Literal.
11692 -- Always accept string literal with component type Any_Character, which
11693 -- occurs in error situations and in comparisons of literals, both of
11694 -- which should accept all literals.
11699 -- If the type is bit-packed, then we always transform the string
11700 -- literal into a full fledged aggregate.
11705 -- Deal with cases of Wide_Wide_String, Wide_String, and String
11707 else
11708 -- For Standard.Wide_Wide_String, or any other type whose component
11709 -- type is Standard.Wide_Wide_Character, we know that all the
11710 -- characters in the string must be acceptable, since the parser
11711 -- accepted the characters as valid character literals.
11716 -- For the case of Standard.String, or any other type whose component
11717 -- type is Standard.Character, we must make sure that there are no
11718 -- wide characters in the string, i.e. that it is entirely composed
11719 -- of characters in range of type Character.
11721 -- If the string literal is the result of a static concatenation, the
11722 -- test has already been performed on the components, and need not be
11723 -- repeated.
11727 then
11731 -- If we are out of range, post error. This is one of the
11732 -- very few places that we place the flag in the middle of
11733 -- a token, right under the offending wide character. Not
11734 -- quite clear if this is right wrt wide character encoding
11735 -- sequences, but it's only an error message.
11737 Error_Msg
11744 -- For the case of Standard.Wide_String, or any other type whose
11745 -- component type is Standard.Wide_Character, we must make sure that
11746 -- there are no wide characters in the string, i.e. that it is
11747 -- entirely composed of characters in range of type Wide_Character.
11749 -- If the string literal is the result of a static concatenation,
11750 -- the test has already been performed on the components, and need
11751 -- not be repeated.
11755 then
11759 -- If we are out of range, post error. This is one of the
11760 -- very few places that we place the flag in the middle of
11761 -- a token, right under the offending wide character.
11763 -- This is not quite right, because characters in general
11764 -- will take more than one character position ???
11766 Error_Msg
11773 -- If the root type is not a standard character, then we will convert
11774 -- the string into an aggregate and will let the aggregate code do
11775 -- the checking. Standard Wide_Wide_Character is also OK here.
11777 else
11781 -- See if the component type of the array corresponding to the string
11782 -- has compile time known bounds. If yes we can directly check
11783 -- whether the evaluation of the string will raise constraint error.
11784 -- Otherwise we need to transform the string literal into the
11785 -- corresponding character aggregate and let the aggregate code do
11786 -- the checking. We use the same transformation if the component
11787 -- type has a static predicate, which will be applied to each
11788 -- character when the aggregate is resolved.
11792 -- Check for the case of full range, where we are definitely OK
11798 -- Here the range is not the complete base type range, so check
11800 declare
11808 begin
11811 then
11817 then
11818 Apply_Compile_Time_Constraint_Error
11820 CE_Range_Check_Failed,
11833 -- If we got here we meed to transform the string literal into the
11834 -- equivalent qualified positional array aggregate. This is rather
11835 -- heavy artillery for this situation, but it is hard work to avoid.
11837 declare
11842 begin
11843 -- Build the character literals, we give them source locations that
11844 -- correspond to the string positions, which is a bit tricky given
11845 -- the possible presence of wide character escape sequences.
11859 -- Should we have a call to Skip_Wide here ???
11861 -- ??? else
11862 -- Skip_Wide (P);
11870 Expression =>
11877 -------------------------
11878 -- Resolve_Target_Name --
11879 -------------------------
11882 begin
11886 -----------------------------
11887 -- Resolve_Type_Conversion --
11888 -----------------------------
11900 -- Set to False to suppress cases where we want to suppress the test
11901 -- for redundancy to avoid possible false positives on this warning.
11903 begin
11904 if not Conv_OK
11906 then
11910 -- If the Operand Etype is Universal_Fixed, then the conversion is
11911 -- never redundant. We need this check because by the time we have
11912 -- finished the rather complex transformation, the conversion looks
11913 -- redundant when it is not.
11918 -- If the operand is marked as Any_Fixed, then special processing is
11919 -- required. This is also a case where we suppress the test for a
11920 -- redundant conversion, since most certainly it is not redundant.
11925 -- Mixed-mode operation involving a literal. Context must be a fixed
11926 -- type which is applied to the literal subsequently.
11928 -- Multiplication and division involving two fixed type operands must
11929 -- yield a universal real because the result is computed in arbitrary
11930 -- precision.
11936 then
11942 or else
11944 then
11945 -- Return if expression is ambiguous
11950 -- If nothing else, the available fixed type is Duration
11952 else
11956 -- Resolve the real operand with largest available precision
11960 else
11966 -- If the operand is a literal (it could be a non-static and
11967 -- illegal exponentiation) check whether the use of Duration
11968 -- is potentially inaccurate.
11973 then
11974 Error_Msg_N
11977 Error_Msg_N
11984 then
11987 else
11998 -- Note: we do the Eval_Type_Conversion call before applying the
11999 -- required checks for a subtype conversion. This is important, since
12000 -- both are prepared under certain circumstances to change the type
12001 -- conversion to a constraint error node, but in the case of
12002 -- Eval_Type_Conversion this may reflect an illegality in the static
12003 -- case, and we would miss the illegality (getting only a warning
12004 -- message), if we applied the type conversion checks first.
12008 -- Even when evaluation is not possible, we may be able to simplify the
12009 -- conversion or its expression. This needs to be done before applying
12010 -- checks, since otherwise the checks may use the original expression
12011 -- and defeat the simplifications. This is specifically the case for
12012 -- elimination of the floating-point Truncation attribute in
12013 -- float-to-int conversions.
12017 -- If after evaluation we still have a type conversion, then we may need
12018 -- to apply checks required for a subtype conversion. But skip them if
12019 -- universal fixed operands are involved, since range checks are handled
12020 -- separately for these cases, after the expansion done by Exp_Fixd.
12026 then
12030 -- Issue warning for conversion of simple object to its own type. We
12031 -- have to test the original nodes, since they may have been rewritten
12032 -- by various optimizations.
12036 -- Here we test for a redundant conversion if the warning mode is
12037 -- active (and was not locally reset), and we have a type conversion
12038 -- from source not appearing in a generic instance.
12040 if Test_Redundant
12043 and then not In_Instance
12044 then
12048 -- If the node is part of a larger expression, the Target_Type
12049 -- may not be the original type of the node if the context is a
12050 -- condition. Recover original type to see if conversion is needed.
12054 then
12058 -- If we have an entity name, then give the warning if the entity
12059 -- is the right type, or if it is a loop parameter covered by the
12060 -- original type (that's needed because loop parameters have an
12061 -- odd subtype coming from the bounds).
12065 and then
12067 or else
12071 -- If not an entity, then type of expression must match
12074 then
12075 -- One more check, do not give warning if the analyzed conversion
12076 -- has an expression with non-static bounds, and the bounds of the
12077 -- target are static. This avoids junk warnings in cases where the
12078 -- conversion is necessary to establish staticness, for example in
12079 -- a case statement.
12083 then
12086 -- Finally, if this type conversion occurs in a context requiring
12087 -- a prefix, and the expression is a qualified expression then the
12088 -- type conversion is not redundant, since a qualified expression
12089 -- is not a prefix, whereas a type conversion is. For example, "X
12090 -- := T'(Funx(...)).Y;" is illegal because a selected component
12091 -- requires a prefix, but a type conversion makes it legal: "X :=
12092 -- T(T'(Funx(...))).Y;"
12094 -- In Ada 2012, a qualified expression is a name, so this idiom is
12095 -- no longer needed, but we still suppress the warning because it
12096 -- seems unfriendly for warnings to pop up when you switch to the
12097 -- newer language version.
12101 | N_Indexed_Component
12102 | N_Selected_Component
12103 | N_Slice
12104 | N_Explicit_Dereference
12105 then
12108 -- Never warn on conversion to Long_Long_Integer'Base since
12109 -- that is most likely an artifact of the extended overflow
12110 -- checking and comes from complex expanded code.
12115 -- Here we give the redundant conversion warning. If it is an
12116 -- entity, give the name of the entity in the message. If not,
12117 -- just mention the expression.
12119 else
12122 Error_Msg_NE -- CODEFIX
12125 else
12126 Error_Msg_NE
12134 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12135 -- No need to perform any interface conversion if the type of the
12136 -- expression coincides with the target type.
12139 and then Expander_Active
12141 then
12142 declare
12146 begin
12147 -- If the type of the operand is a limited view, use nonlimited
12148 -- view when available. If it is a class-wide type, recover the
12149 -- class-wide type of the nonlimited view.
12153 then
12158 -- It seems that Non_Limited_View should also be applied for
12159 -- Target when it has a limited view, but that leads to missing
12160 -- error checks on interface conversions further below. ???
12165 -- If the type of the operand is a limited view, use nonlimited
12166 -- view when available. If it is a class-wide type, recover the
12167 -- class-wide type of the nonlimited view.
12171 then
12179 -- If the target type is a limited view, use nonlimited view
12180 -- when available.
12184 then
12192 -- Conversion from interface type
12194 -- It seems that it would be better for the error checks below
12195 -- to be performed as part of Validate_Conversion (and maybe some
12196 -- of the error checks above could be moved as well?). ???
12200 -- Ada 2005 (AI-217): Handle entities from limited views
12204 Error_Msg_NE -- CODEFIX
12207 Error_Msg_N
12209 N);
12212 and then not
12215 then
12217 Error_Msg_NE -- CODEFIX
12220 Error_Msg_N
12222 N);
12224 else
12228 -- Conversion to interface type
12232 -- Handle subtypes
12239 or else Interface_Present_In_Ancestor
12242 then
12244 else
12247 Error_Msg_N
12255 -- Ada 2012: Once the type conversion is resolved, check whether the
12256 -- operand satisfies a static predicate of the target subtype, if any.
12257 -- In the static expression case, a predicate check failure is an error.
12260 Check_Expression_Against_Static_Predicate
12264 -- If at this stage we have a fixed to integer conversion, make sure the
12265 -- Do_Range_Check flag is set, because such conversions in general need
12266 -- a range check. We only need this if expansion is off, see above why.
12269 and then not Expander_Active
12274 then
12278 -- Generating C code a type conversion of an access to constrained
12279 -- array type to access to unconstrained array type involves building
12280 -- a fat pointer which in general cannot be generated on the fly. We
12281 -- remove side effects in order to store the result of the conversion
12282 -- into a temporary.
12284 if Modify_Tree_For_C
12291 then
12296 ----------------------
12297 -- Resolve_Unary_Op --
12298 ----------------------
12307 begin
12308 -- Deal with intrinsic unary operators
12314 then
12319 -- Deal with universal cases
12328 -- Generate warning for negative literal of a modular type, unless it is
12329 -- enclosed directly in a type qualification or a type conversion, as it
12330 -- is likely not what the user intended. We don't issue the warning for
12331 -- the common use of -1 to denote OxFFFF_FFFF...
12333 if Warn_On_Suspicious_Modulus_Value
12338 | N_Type_Conversion
12340 then
12341 Error_Msg_N
12346 Error_Msg_N
12350 -- Generate warning for expressions like abs (x mod 2)
12352 if Warn_On_Redundant_Constructs
12354 then
12358 Error_Msg_N -- CODEFIX
12363 -- Deal with reference generation
12370 -- Set overflow checking bit. Much cleverer code needed here eventually
12371 -- and perhaps the Resolve routines should be separated for the various
12372 -- arithmetic operations, since they will need different processing ???
12380 -- Generate warning for expressions like -5 mod 3 for integers. No need
12381 -- to worry in the floating-point case, since parens do not affect the
12382 -- result so there is no point in giving in a warning.
12384 declare
12393 begin
12394 if Warn_On_Questionable_Missing_Parens
12398 then
12401 -- We are looking for cases where the right operand is not
12402 -- parenthesized, and is a binary operator, multiply, divide, or
12403 -- mod. These are the cases where the grouping can affect results.
12407 then
12408 -- For mod, we always give the warning, since the value is
12409 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12410 -- -(5 mod 315)). But for the other cases, the only concern is
12411 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12412 -- overflows, but (-2) * 64 does not). So we try to give the
12413 -- message only when overflow is possible.
12417 then
12422 else
12428 else
12432 -- Note that the test below is deliberately excluding the
12433 -- largest negative number, since that is a potentially
12434 -- troublesome case (e.g. -2 * x, where the result is the
12435 -- largest negative integer has an overflow with 2 * x).
12442 -- For the multiplication case, the only case we have to worry
12443 -- about is when (-a)*b is exactly the largest negative number
12444 -- so that -(a*b) can cause overflow. This can only happen if
12445 -- a is a power of 2, and more generally if any operand is a
12446 -- constant that is not a power of 2, then the parentheses
12447 -- cannot affect whether overflow occurs. We only bother to
12448 -- test the left most operand
12450 -- Loop looking at left operands for one that has known value
12457 -- Operand value of 0 or 1 skips warning
12462 -- Otherwise check power of 2, if power of 2, warn, if
12463 -- anything else, skip warning.
12465 else
12469 else
12478 -- Keep looking at left operands
12483 -- For rem or "/" we can only have a problematic situation
12484 -- if the divisor has a value of minus one or one. Otherwise
12485 -- overflow is impossible (divisor > 1) or we have a case of
12486 -- division by zero in any case.
12491 then
12495 -- If we fall through warning should be issued
12497 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12499 Error_Msg_N
12506 ----------------------------------
12507 -- Resolve_Unchecked_Expression --
12508 ----------------------------------
12510 procedure Resolve_Unchecked_Expression
12513 is
12514 begin
12519 ---------------------------------------
12520 -- Resolve_Unchecked_Type_Conversion --
12521 ---------------------------------------
12523 procedure Resolve_Unchecked_Type_Conversion
12526 is
12532 begin
12533 -- Resolve operand using its own type
12537 -- If the expression is a conversion to universal integer of an
12538 -- an expression with an integer type, then we can eliminate the
12539 -- intermediate conversion to universal integer.
12544 then
12549 -- In an inlined context, the unchecked conversion may be applied
12550 -- to a literal, in which case its type is the type of the context.
12551 -- (In other contexts conversions cannot apply to literals).
12553 if In_Inlined_Body
12557 then
12565 ------------------------------
12566 -- Rewrite_Operator_As_Call --
12567 ------------------------------
12574 begin
12581 New_N :=
12592 ------------------------------
12593 -- Rewrite_Renamed_Operator --
12594 ------------------------------
12596 procedure Rewrite_Renamed_Operator
12600 is
12605 begin
12606 -- Do not perform this transformation within a pre/postcondition,
12607 -- because the expression will be reanalyzed, and the transformation
12608 -- might affect the visibility of the operator, e.g. in an instance.
12609 -- Note that fully analyzed and expanded pre/postconditions appear as
12610 -- pragma Check equivalents.
12616 -- Likewise when an expression function is being preanalyzed, since the
12617 -- expression will be reanalyzed as part of the generated body.
12620 declare
12622 begin
12625 N_Expression_Function
12626 then
12642 -- Indicate that both the original entity and its renaming are
12643 -- referenced at this point.
12650 -- If the context type is private, add the appropriate conversions so
12651 -- that the operator is applied to the full view. This is done in the
12652 -- routines that resolve intrinsic operators.
12656 when N_Op_Add
12657 | N_Op_Divide
12658 | N_Op_Expon
12659 | N_Op_Mod
12660 | N_Op_Multiply
12661 | N_Op_Rem
12662 | N_Op_Subtract
12663 =>
12666 when N_Op_Abs
12667 | N_Op_Minus
12668 | N_Op_Plus
12669 =>
12678 -----------------------
12679 -- Set_Slice_Subtype --
12680 -----------------------
12682 -- Build an implicit subtype declaration to represent the type delivered by
12683 -- the slice. This is an abbreviated version of an array subtype. We define
12684 -- an index subtype for the slice, using either the subtype name or the
12685 -- discrete range of the slice. To be consistent with index usage elsewhere
12686 -- we create a list header to hold the single index. This list is not
12687 -- otherwise attached to the syntax tree.
12698 begin
12704 else
12705 -- We force the evaluation of a range. This is definitely needed in
12706 -- the renamed case, and seems safer to do unconditionally. Note in
12707 -- any case that since we will create and insert an Itype referring
12708 -- to this range, we must make sure any side effect removal actions
12709 -- are inserted before the Itype definition.
12715 -- If the discrete range is given by a subtype indication, the
12716 -- type of the slice is the base of the subtype mark.
12719 declare
12721 begin
12730 -- Take a new copy of Drange (where bounds have been rewritten to
12731 -- reference side-effect-free names). Using a separate tree ensures
12732 -- that further expansion (e.g. while rewriting a slice assignment
12733 -- into a FOR loop) does not attempt to remove side effects on the
12734 -- bounds again (which would cause the bounds in the index subtype
12735 -- definition to refer to temporaries before they are defined) (the
12736 -- reason is that some names are considered side effect free here
12737 -- for the subtype, but not in the context of a loop iteration
12738 -- scheme).
12760 -- The Etype of the existing Slice node is reset to this slice subtype.
12761 -- Its bounds are obtained from its first index.
12765 -- For bit-packed slice subtypes, freeze immediately (except in the case
12766 -- of being in a "spec expression" where we never freeze when we first
12767 -- see the expression).
12772 -- For all other cases insert an itype reference in the slice's actions
12773 -- so that the itype is frozen at the proper place in the tree (i.e. at
12774 -- the point where actions for the slice are analyzed). Note that this
12775 -- is different from freezing the itype immediately, which might be
12776 -- premature (e.g. if the slice is within a transient scope). This needs
12777 -- to be done only if expansion is enabled.
12784 --------------------------------
12785 -- Set_String_Literal_Subtype --
12786 --------------------------------
12794 begin
12806 -- The low bound is set from the low bound of the corresponding index
12807 -- type. Note that we do not store the high bound in the string literal
12808 -- subtype, but it can be deduced if necessary from the length and the
12809 -- low bound.
12814 -- If the lower bound is not static we create a range for the string
12815 -- literal, using the index type and the known length of the literal.
12816 -- If the length is 1, then the upper bound is set to a mere copy of
12817 -- the lower bound; or else, if the index type is a signed integer,
12818 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
12819 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
12821 else
12822 declare
12832 begin
12837 High_Bound :=
12842 else
12843 High_Bound :=
12846 Prefix =>
12850 Left_Opnd =>
12853 Prefix =>
12855 Expressions =>
12857 Right_Opnd =>
12862 Set_String_Literal_Low_Bound
12865 else
12866 -- If the index type is an enumeration type, build bounds
12867 -- expression with attributes.
12869 Set_String_Literal_Low_Bound
12873 Prefix =>
12877 Analyze_And_Resolve
12880 -- Build bona fide subtype for the string, and wrap it in an
12881 -- unchecked conversion, because the back end expects the
12882 -- String_Literal_Subtype to have a static lower bound.
12884 Index_Subtype :=
12891 -- In this context, the Index_Type may already have a constraint,
12892 -- so use common base type on string subtype. The base type may
12893 -- be used when generating attributes of the string, for example
12894 -- in the context of a slice assignment.
12916 ------------------------------
12917 -- Simplify_Type_Conversion --
12918 ------------------------------
12921 begin
12923 declare
12928 begin
12929 -- Special processing if the conversion is the expression of a
12930 -- Rounding or Truncation attribute reference. In this case we
12931 -- replace:
12933 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
12935 -- by
12937 -- ityp (x)
12939 -- with the Float_Truncate flag set to False or True respectively,
12940 -- which is more efficient. We reuse Rounding for Machine_Rounding
12941 -- as System.Fat_Gen, which is a permissible behavior.
12944 and then
12950 | Name_Machine_Rounding
12951 | Name_Truncation
12952 then
12953 declare
12956 begin
12962 -- Special processing for the conversion of an integer literal to
12963 -- a dynamic type: we first convert the literal to the root type
12964 -- and then convert the result to the target type, the goal being
12965 -- to avoid doing range checks in universal integer.
12971 then
12975 -- If the expression is a conversion to universal integer of an
12976 -- an expression with an integer type, then we can eliminate the
12977 -- intermediate conversion to universal integer.
12982 then
12990 ------------------------------
12991 -- Try_User_Defined_Literal --
12992 ------------------------------
12994 function Try_User_Defined_Literal
12997 is
12998 begin
13000 | N_Op_Rem | N_Op_Subtract
13001 then
13003 -- Both operands must have the same type as the context.
13004 -- (ignoring for now fixed-point and exponentiation ops).
13012 if
13014 then
13019 else
13024 -- For other operators the context does not impose a type on
13025 -- the operands, but their types must match.
13029 and then
13030 Has_Applicable_User_Defined_Literal
13032 then
13038 and then
13039 Has_Applicable_User_Defined_Literal
13041 then
13044 else
13049 and then
13051 then
13060 -----------------------------
13061 -- Unique_Fixed_Point_Type --
13062 -----------------------------
13066 -- Give error messages for true ambiguity. Messages are posted on node
13067 -- N, and entities T1, T2 are the possible interpretations.
13069 -----------------------
13070 -- Fixed_Point_Error --
13071 -----------------------
13074 begin
13080 -- Local variables
13088 -- Start of processing for Unique_Fixed_Point_Type
13090 begin
13091 -- The operations on Duration are visible, so Duration is always a
13092 -- possible interpretation.
13096 -- Look for fixed-point types in enclosing scopes
13105 then
13109 else
13120 -- Look for visible fixed type declarations in the context
13131 then
13135 else
13150 else
13151 -- When the context is a type conversion, issue the warning on the
13152 -- expression of the conversion because it is the actual operation.
13156 else
13160 Error_Msg_NE
13167 ----------------------
13168 -- Valid_Conversion --
13169 ----------------------
13171 function Valid_Conversion
13176 is
13181 function Conversion_Check
13184 -- Little routine to post Msg if Valid is False, returns Valid value
13187 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13189 procedure Conversion_Error_NE
13193 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13196 -- Return True if expression is within an instance but is not in one of
13197 -- the actuals of the instantiation. Type conversions within an instance
13198 -- are not rechecked because type visibility may lead to spurious errors
13199 -- but conversions in an actual for a formal object must be checked.
13201 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13203 -- Implicit anonymous-to-named access type conversions are not allowed
13204 -- if the "statically deeper than" relationship does not apply to the
13205 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13206 -- We deal with most such cases elsewhere so that we can emit more
13207 -- specific error messages (e.g., if the operand is an access parameter
13208 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13209 -- here is where we catch the case where the operand is an access
13210 -- discriminant selected from a dereference of another such "bad"
13211 -- conversion argument.
13213 function Valid_Tagged_Conversion
13216 -- Specifically test for validity of tagged conversions
13219 -- Check index and component conformance, and accessibility levels if
13220 -- the component types are anonymous access types (Ada 2005).
13222 ----------------------
13223 -- Conversion_Check --
13224 ----------------------
13226 function Conversion_Check
13229 is
13230 begin
13231 if not Valid
13233 -- A generic unit has already been analyzed and we have verified
13234 -- that a particular conversion is OK in that context. Since the
13235 -- instance is reanalyzed without relying on the relationships
13236 -- established during the analysis of the generic, it is possible
13237 -- to end up with inconsistent views of private types. Do not emit
13238 -- the error message in such cases. The rest of the machinery in
13239 -- Valid_Conversion still ensures the proper compatibility of
13240 -- target and operand types.
13242 and then not In_Instance_Code
13243 then
13250 ------------------------
13251 -- Conversion_Error_N --
13252 ------------------------
13255 begin
13261 -------------------------
13262 -- Conversion_Error_NE --
13263 -------------------------
13265 procedure Conversion_Error_NE
13269 is
13270 begin
13276 ----------------------
13277 -- In_Instance_Code --
13278 ----------------------
13283 begin
13287 else
13291 -- The expression is part of an actual object if it appears in
13292 -- the generated object declaration in the instance.
13296 then
13299 else
13300 exit when
13309 -- Otherwise the expression appears within the instantiated unit
13315 --------------------------------------------------
13316 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13317 --------------------------------------------------
13319 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13321 is
13327 begin
13339 -- return False if Expr not of form <prefix>.all.Some_Component
13343 then
13344 -- conditional expressions, declare expressions ???
13351 -- The "statically deeper relationship" does not apply
13352 -- to generic formal access types, so a prefix of such
13353 -- a type is a "bad" prefix.
13358 -- The "statically deeper relationship" does apply to
13359 -- any other named access type.
13368 -- The "statically deeper relationship" applies to some
13369 -- anonymous access types and not to others. Return
13370 -- True for the cases where it does not apply. Also check
13371 -- recursively for the
13372 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13373 -- where the correct result depends on <prefix>.
13376 N_Procedure_Specification | -- access parameter
13377 N_Function_Specification | -- access parameter
13378 N_Object_Declaration -- saooaaat
13382 ----------------------------
13383 -- Valid_Array_Conversion --
13384 ----------------------------
13401 begin
13402 -- Error if wrong number of dimensions
13404 if
13406 then
13407 Conversion_Error_N
13411 -- Number of dimensions matches
13413 else
13414 -- Loop through indexes of the two arrays
13422 -- Error if index types are incompatible
13428 then
13429 Conversion_Error_N
13431 Operand);
13439 -- If component types have same base type, all set
13444 -- Here if base types of components are not the same. The only
13445 -- time this is allowed is if we have anonymous access types.
13447 -- The conversion of arrays of anonymous access types can lead
13448 -- to dangling pointers. AI-392 formalizes the accessibility
13449 -- checks that must be applied to such conversions to prevent
13450 -- out-of-scope references.
13453 E_Anonymous_Access_Type
13454 | E_Anonymous_Access_Subprogram_Type
13456 and then
13458 then
13461 then
13464 Conversion_Error_N
13474 -- Conversion not allowed because of accessibility levels
13476 else
13477 Conversion_Error_N
13483 else
13487 -- All other cases where component base types do not match
13489 else
13490 Conversion_Error_N
13492 Operand);
13496 -- Check that component subtypes statically match. For numeric
13497 -- types this means that both must be either constrained or
13498 -- unconstrained. For enumeration types the bounds must match.
13499 -- All of this is checked in Subtypes_Statically_Match.
13501 if not Subtypes_Statically_Match
13503 then
13504 Conversion_Error_N
13513 -----------------------------
13514 -- Valid_Tagged_Conversion --
13515 -----------------------------
13517 function Valid_Tagged_Conversion
13520 is
13521 begin
13522 -- Upward conversions are allowed (RM 4.6(22))
13526 then
13529 -- Downward conversion are allowed if the operand is class-wide
13530 -- (RM 4.6(23)).
13534 then
13539 then
13540 return
13544 -- Ada 2005 (AI-251): The conversion to/from interface types is
13545 -- always valid. The types involved may be class-wide (sub)types.
13549 then
13552 -- If the operand is a class-wide type obtained through a limited_
13553 -- with clause, and the context includes the nonlimited view, use
13554 -- it to determine whether the conversion is legal.
13560 then
13565 then
13568 else
13569 Conversion_Error_NE
13576 -- Start of processing for Valid_Conversion
13578 begin
13582 declare
13590 begin
13591 -- Remove procedure calls, which syntactically cannot appear in
13592 -- this context, but which cannot be removed by type checking,
13593 -- because the context does not impose a type.
13595 -- The node may be labelled overloaded, but still contain only one
13596 -- interpretation because others were discarded earlier. If this
13597 -- is the case, retain the single interpretation if legal.
13605 then
13606 -- More than one candidate interpretation is available
13614 -- When compiling for a system where Address is of a visible
13615 -- integer type, spurious ambiguities can be produced when
13616 -- arithmetic operations have a literal operand and return
13617 -- System.Address or a descendant of it. These ambiguities
13618 -- are usually resolved by the context, but for conversions
13619 -- there is no context type and the removal of the spurious
13620 -- operations must be done explicitly here.
13622 if not Address_Is_Private
13624 then
13649 Conversion_Error_N
13652 -- If the interpretation involves a standard operator, use
13653 -- the location of the type, which may be user-defined.
13657 else
13661 Conversion_Error_N -- CODEFIX
13666 else
13670 Conversion_Error_N -- CODEFIX
13682 -- Deal with conversion of integer type to address if the pragma
13683 -- Allow_Integer_Address is in effect. We convert the conversion to
13684 -- an unchecked conversion in this case and we are all done.
13692 -- If we are within a child unit, check whether the type of the
13693 -- expression has an ancestor in a parent unit, in which case it
13694 -- belongs to its derivation class even if the ancestor is private.
13695 -- See RM 7.3.1 (5.2/3).
13699 -- Numeric types
13703 -- A universal fixed expression can be converted to any numeric type
13708 -- Also no need to check when in an instance or inlined body, because
13709 -- the legality has been established when the template was analyzed.
13710 -- Furthermore, numeric conversions may occur where only a private
13711 -- view of the operand type is visible at the instantiation point.
13712 -- This results in a spurious error if we check that the operand type
13713 -- is a numeric type.
13715 -- Note: in a previous version of this unit, the following tests were
13716 -- applied only for generated code (Comes_From_Source set to False),
13717 -- but in fact the test is required for source code as well, since
13718 -- this situation can arise in source code.
13723 -- Otherwise we need the conversion check
13725 else
13726 return Conversion_Check
13728 or else
13734 -- Array types
13740 then
13741 Conversion_Error_N
13745 else
13749 -- Ada 2005 (AI-251): Internally generated conversions of access to
13750 -- interface types added to force the displacement of the pointer to
13751 -- reference the corresponding dispatch table.
13756 then
13759 -- Ada 2005 (AI-251): Anonymous access types where target references an
13760 -- interface type.
13764 E_General_Access_Type | E_Anonymous_Access_Type
13766 then
13767 -- Check the static accessibility rule of 4.6(17). Note that the
13768 -- check is not enforced when within an instance body, since the
13769 -- RM requires such cases to be caught at run time.
13771 -- If the operand is a rewriting of an allocator no check is needed
13772 -- because there are no accessibility issues.
13780 then
13781 -- In an instance, this is a run-time check, but one we know
13782 -- will fail, so generate an appropriate warning. The raise
13783 -- will be generated by Expand_N_Type_Conversion.
13787 Conversion_Error_N
13789 Operand);
13792 else
13793 Conversion_Error_N
13795 Operand);
13799 -- Special accessibility checks are needed in the case of access
13800 -- discriminants declared for a limited type.
13804 then
13805 -- When the operand is a selected access discriminant the check
13806 -- needs to be made against the level of the object denoted by
13807 -- the prefix of the selected name (Accessibility_Level handles
13808 -- checking the prefix of the operand for this case).
13811 and then Static_Accessibility_Level
13814 then
13815 -- In an instance, this is a run-time check, but one we know
13816 -- will fail, so generate an appropriate warning. The raise
13817 -- will be generated by Expand_N_Type_Conversion.
13821 Conversion_Error_N
13826 -- Real error if not in instance body
13828 else
13829 Conversion_Error_N
13836 -- The case of a reference to an access discriminant from
13837 -- within a limited type declaration (which will appear as
13838 -- a discriminal) is always illegal because the level of the
13839 -- discriminant is considered to be deeper than any (nameable)
13840 -- access type.
13844 and then
13847 then
13848 Conversion_Error_N
13850 Operand);
13858 -- General and anonymous access types
13861 E_General_Access_Type | E_Anonymous_Access_Type
13862 and then
13863 Conversion_Check
13865 and then
13867 E_Access_Subprogram_Type |
13868 E_Access_Protected_Subprogram_Type,
13870 then
13873 then
13874 Conversion_Error_N
13879 -- Check the static accessibility rule of 4.6(17). Note that the
13880 -- check is not enforced when within an instance body, since the RM
13881 -- requires such cases to be caught at run time.
13886 N_Object_Declaration
13887 then
13888 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
13889 -- conversions from an anonymous access type to a named general
13890 -- access type. Such conversions are not allowed in the case of
13891 -- access parameters and stand-alone objects of an anonymous
13892 -- access type. The implicit conversion case is recognized by
13893 -- testing that Comes_From_Source is False and that it's been
13894 -- rewritten. The Comes_From_Source test isn't sufficient because
13895 -- nodes in inlined calls to predefined library routines can have
13896 -- Comes_From_Source set to False. (Is there a better way to test
13897 -- for implicit conversions???).
13898 --
13899 -- Do not treat a rewritten 'Old attribute reference like other
13900 -- rewrite substitutions. This makes a difference, for example,
13901 -- in the case where we are generating the expansion of a
13902 -- membership test of the form
13903 -- Saooaaat'Old in Named_Access_Type
13904 -- because in this case Valid_Conversion needs to return True
13905 -- (otherwise the expansion will be False - see the call site
13906 -- in exp_ch4.adb).
13914 then
13917 -- When applying restriction No_Dynamic_Accessibility_Check,
13918 -- implicit conversions are allowed when the operand type is
13919 -- not deeper than the target type.
13924 then
13925 Conversion_Error_N
13929 -- Implicit conversions aren't allowed for objects of an
13930 -- anonymous access type, since such objects have nonstatic
13931 -- levels in Ada 2012.
13934 = N_Object_Declaration
13935 then
13936 Conversion_Error_N
13941 -- Implicit conversions aren't allowed for anonymous access
13942 -- parameters. We exclude anonymous access results as well
13943 -- as universal_access "=".
13947 N_Function_Specification |
13948 N_Procedure_Specification
13950 then
13951 Conversion_Error_N
13956 -- Detect access discriminant values that are illegal
13957 -- implicit anonymous-to-named access conversion operands.
13960 then
13961 Conversion_Error_N
13966 -- In other cases, the level of the operand's type must be
13967 -- statically less deep than that of the target type, else
13968 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
13972 then
13973 Conversion_Error_N
13980 -- Check if the operand is deeper than the target type, taking
13981 -- care to avoid the case where we are converting a result of a
13982 -- function returning an anonymous access type since the "master
13983 -- of the call" would be target type of the conversion unless
13984 -- the target type is anonymous access as well - see RM 3.10.2
13985 -- (10.3/3).
13987 -- Note that when the restriction No_Dynamic_Accessibility_Checks
13988 -- is in effect wei also want to proceed with the conversion check
13989 -- described above.
13994 /= N_Function_Specification
13998 -- Check we are not in a return value ???
14001 or else
14004 then
14005 -- In an instance, this is a run-time check, but one we know
14006 -- will fail, so generate an appropriate warning. The raise
14007 -- will be generated by Expand_N_Type_Conversion.
14011 Conversion_Error_N
14013 Operand);
14016 -- If not in an instance body, this is a real error
14018 else
14019 -- Avoid generation of spurious error message
14022 Conversion_Error_N
14024 Operand);
14030 -- Special accessibility checks are needed in the case of access
14031 -- discriminants declared for a limited type.
14035 then
14036 -- When the operand is a selected access discriminant the check
14037 -- needs to be made against the level of the object denoted by
14038 -- the prefix of the selected name (Accessibility_Level handles
14039 -- checking the prefix of the operand for this case).
14042 and then Static_Accessibility_Level
14045 then
14046 -- In an instance, this is a run-time check, but one we know
14047 -- will fail, so generate an appropriate warning. The raise
14048 -- will be generated by Expand_N_Type_Conversion.
14052 Conversion_Error_N
14057 -- If not in an instance body, this is a real error
14059 else
14060 Conversion_Error_N
14067 -- The case of a reference to an access discriminant from
14068 -- within a limited type declaration (which will appear as
14069 -- a discriminal) is always illegal because the level of the
14070 -- discriminant is considered to be deeper than any (nameable)
14071 -- access type.
14074 and then
14077 then
14078 Conversion_Error_N
14080 Operand);
14086 -- In the presence of limited_with clauses we have to use nonlimited
14087 -- views, if available.
14091 -- Helper function to handle limited views
14093 --------------------------
14094 -- Full_Designated_Type --
14095 --------------------------
14100 begin
14101 -- Handle the limited view of a type
14105 then
14107 else
14112 -- Local Declarations
14120 -- Start of processing for Check_Limited
14122 begin
14126 else
14128 Conversion_Error_NE
14133 -- Ada 2005 AI-384: legality rule is symmetric in both
14134 -- designated types. The conversion is legal (with possible
14135 -- constraint check) if either designated type is
14136 -- unconstrained.
14139 or else
14141 and then
14144 then
14145 -- Special case, if Value_Size has been used to make the
14146 -- sizes different, the conversion is not allowed even
14147 -- though the subtypes statically match.
14152 then
14153 Conversion_Error_NE
14156 Conversion_Error_NE
14161 -- Normal case where conversion is allowed
14163 else
14167 else
14168 Error_Msg_NE
14176 -- Access to subprogram types. If the operand is an access parameter,
14177 -- the type has a deeper accessibility that any master, and cannot be
14178 -- assigned. We must make an exception if the conversion is part of an
14179 -- assignment and the target is the return object of an extended return
14180 -- statement, because in that case the accessibility check takes place
14181 -- after the return.
14185 -- Note: this test of Opnd_Type is there to prevent entering this
14186 -- branch in the case of a remote access to subprogram type, which
14187 -- is internally represented as an E_Record_Type.
14190 then
14194 and then
14198 then
14199 Conversion_Error_N
14201 Operand);
14202 Conversion_Error_N
14205 Operand);
14207 Error_Msg_NE
14212 -- Check that the designated types are subtype conformant
14218 -- Check the static accessibility rule of 4.6(20)
14222 then
14223 Conversion_Error_N
14225 Operand);
14227 -- Check that if the operand type is declared in a generic body,
14228 -- then the target type must be declared within that same body
14229 -- (enforces last sentence of 4.6(20)).
14232 declare
14238 begin
14245 Conversion_Error_N
14252 -- Check that the strub modes are compatible.
14253 -- We wish to reject explicit conversions only for
14254 -- incompatible modes.
14256 return Conversion_Check
14257 (Compatible_Strub_Modes
14262 -- Remote access to subprogram types
14266 then
14267 -- It is valid to convert from one RAS type to another provided
14268 -- that their specification statically match.
14270 -- Note: at this point, remote access to subprogram types have been
14271 -- expanded to their E_Record_Type representation, and we need to
14272 -- go back to the original access type definition using the
14273 -- Corresponding_Remote_Type attribute in order to check that the
14274 -- designated profiles match.
14279 Check_Subtype_Conformant
14282 Old_Id =>
14284 Err_Loc =>
14285 N);
14287 -- Check that the strub modes are compatible.
14288 -- We wish to reject explicit conversions only for
14289 -- incompatible modes.
14291 return Conversion_Check
14292 (Compatible_Strub_Modes
14297 -- If it was legal in the generic, it's legal in the instance
14302 -- If both are tagged types, check legality of view conversions
14305 and then
14307 then
14310 -- Types derived from the same root type are convertible
14315 -- In an instance or an inlined body, there may be inconsistent views of
14316 -- the same type, or of types derived from a common root.
14319 and then
14322 then
14325 -- Special check for common access type error case
14329 then
14331 Conversion_Error_NE -- CODEFIX
14335 -- Here we have a real conversion error
14337 else
14338 -- Check for missing regular with_clause when only a limited view of
14339 -- target is available.
14342 Conversion_Error_NE
14345 Conversion_Error_NE
14350 and then In_Package_Body
14351 then
14352 Conversion_Error_NE
14354 Conversion_Error_NE
14358 else
14359 Conversion_Error_NE