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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) 1992-2014, 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 ------------------------------------------------------------------------------
84 -----------------------
85 -- Local Subprograms --
86 -----------------------
88 -- Second pass (top-down) type checking and overload resolution procedures
89 -- Typ is the type required by context. These procedures propagate the type
90 -- information recursively to the descendants of N. If the node is not
91 -- overloaded, its Etype is established in the first pass. If overloaded,
92 -- the Resolve routines set the correct type. For arith. operators, the
93 -- Etype is the base type of the context.
95 -- Note that Resolve_Attribute is separated off in Sem_Attr
98 -- Enforce the restrictions on the use of discriminants when constraining
99 -- a component of a discriminated type (record or concurrent type).
102 -- Given a node for an operator associated with type T, check that
103 -- the operator is visible. Operators all of whose operands are
104 -- universal must be checked for visibility during resolution
105 -- because their type is not determinable based on their operands.
107 procedure Check_Fully_Declared_Prefix
110 -- Check that the type of the prefix of a dereference is not incomplete
113 -- Determine whether node Ghost_Ref appears within a Ghost-friendly context
114 -- where Ghost entity Ghost_Id can safely reside.
117 -- Given a call node, N, which is known to occur immediately within the
118 -- subprogram being called, determines whether it is a detectable case of
119 -- an infinite recursion, and if so, outputs appropriate messages. Returns
120 -- True if an infinite recursion is detected, and False otherwise.
123 -- If the type of the object being initialized uses the secondary stack
124 -- directly or indirectly, create a transient scope for the call to the
125 -- init proc. This is because we do not create transient scopes for the
126 -- initialization of individual components within the init proc itself.
127 -- Could be optimized away perhaps?
130 -- N is the node for a logical operator. If the operator is predefined, and
131 -- the root type of the operands is Standard.Boolean, then a check is made
132 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
133 -- the style check for Style_Check_Boolean_And_Or.
136 -- N is either an indexed component or a selected component. This function
137 -- returns true if the prefix refers to an object that has an address
138 -- clause (the case in which we may want to issue a warning).
141 -- Determine whether E is an access type declared by an access declaration,
142 -- and not an (anonymous) allocator type.
145 -- Utility to check whether the entity for an operator is a predefined
146 -- operator, in which case the expression is left as an operator in the
147 -- tree (else it is rewritten into a call). An instance of an intrinsic
148 -- conversion operation may be given an operator name, but is not treated
149 -- like an operator. Note that an operator that is an imported back-end
150 -- builtin has convention Intrinsic, but is expected to be rewritten into
151 -- a call, so such an operator is not treated as predefined by this
152 -- predicate.
155 -- If a default expression in entry call N depends on the discriminants
156 -- of the task, it must be replaced with a reference to the discriminant
157 -- of the task being called.
159 procedure Resolve_Op_Concat_Arg
164 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
165 -- concatenation operator. The operand is either of the array type or of
166 -- the component type. If the operand is an aggregate, and the component
167 -- type is composite, this is ambiguous if component type has aggregates.
170 -- Does the first part of the work of Resolve_Op_Concat
173 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
174 -- has been resolved. See Resolve_Op_Concat for details.
212 function Operator_Kind
215 -- Utility to map the name of an operator into the corresponding Node. Used
216 -- by other node rewriting procedures.
219 -- Resolve actuals of call, and add default expressions for missing ones.
220 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
221 -- called subprogram.
224 -- Called from Resolve_Call, when the prefix denotes an entry or element
225 -- of entry family. Actuals are resolved as for subprograms, and the node
226 -- is rebuilt as an entry call. Also called for protected operations. Typ
227 -- is the context type, which is used when the operation is a protected
228 -- function with no arguments, and the return value is indexed.
231 -- A call to a user-defined intrinsic operator is rewritten as a call to
232 -- the corresponding predefined operator, with suitable conversions. Note
233 -- that this applies only for intrinsic operators that denote predefined
234 -- operators, not ones that are intrinsic imports of back-end builtins.
237 -- Ditto, for arithmetic unary operators
240 -- If an operator node resolves to a call to a user-defined operator,
241 -- rewrite the node as a function call.
243 procedure Make_Call_Into_Operator
247 -- Inverse transformation: if an operator is given in functional notation,
248 -- then after resolving the node, transform into an operator node, so
249 -- that operands are resolved properly. Recall that predefined operators
250 -- do not have a full signature and special resolution rules apply.
252 procedure Rewrite_Renamed_Operator
256 -- An operator can rename another, e.g. in an instantiation. In that
257 -- case, the proper operator node must be constructed and resolved.
260 -- The String_Literal_Subtype is built for all strings that are not
261 -- operands of a static concatenation operation. If the argument is
262 -- not a N_String_Literal node, then the call has no effect.
265 -- Build subtype of array type, with the range specified by the slice
268 -- Called after N has been resolved and evaluated, but before range checks
269 -- have been applied. Currently simplifies a combination of floating-point
270 -- to integer conversion and Rounding or Truncation attribute.
273 -- A universal_fixed expression in an universal context is unambiguous if
274 -- there is only one applicable fixed point type. Determining whether there
275 -- is only one requires a search over all visible entities, and happens
276 -- only in very pathological cases (see 6115-006).
278 -------------------------
279 -- Ambiguous_Character --
280 -------------------------
285 begin
289 -- First the ones in Standard
294 -- Include Wide_Wide_Character in Ada 2005 mode
300 -- Now any other types that match
310 -------------------------
311 -- Analyze_And_Resolve --
312 -------------------------
315 begin
321 begin
326 -- Versions with check(s) suppressed
328 procedure Analyze_And_Resolve
332 is
335 begin
337 declare
339 begin
345 else
346 declare
348 begin
356 and then Scope_Is_Transient
357 then
358 -- This can only happen if a transient scope was created for an inner
359 -- expression, which will be removed upon completion of the analysis
360 -- of an enclosing construct. The transient scope must have the
361 -- suppress status of the enclosing environment, not of this Analyze
362 -- call.
365 Scope_Suppress;
369 procedure Analyze_And_Resolve
372 is
375 begin
377 declare
379 begin
385 else
386 declare
388 begin
397 Scope_Suppress;
401 ----------------------------
402 -- Check_Discriminant_Use --
403 ----------------------------
411 begin
412 -- Any use in a spec-expression is legal
419 -- Discriminant cannot be used to constrain a scalar type
426 then
431 -- The following check catches the unusual case where a
432 -- discriminant appears within an index constraint that is part of
433 -- a larger expression within a constraint on a component, e.g. "C
434 -- : Int range 1 .. F (new A(1 .. D))". For now we only check case
435 -- of record components, and note that a similar check should also
436 -- apply in the case of discriminant constraints below. ???
438 -- Note that the check for N_Subtype_Declaration below is to
439 -- detect the valid use of discriminants in the constraints of a
440 -- subtype declaration when this subtype declaration appears
441 -- inside the scope of a record type (which is syntactically
442 -- illegal, but which may be created as part of derived type
443 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
444 -- for more info.
448 and then not
450 and then
452 N_Subtype_Declaration)
454 then
455 Error_Msg_N
460 -- Detect a common error:
462 -- type R (D : Positive := 100) is record
463 -- Name : String (1 .. D);
464 -- end record;
466 -- The default value causes an object of type R to be allocated
467 -- with room for Positive'Last characters. The RM does not mandate
468 -- the allocation of the maximum size, but that is what GNAT does
469 -- so we should warn the programmer that there is a problem.
478 -- Return True if type T has a large enough range that any
479 -- array whose index type covered the whole range of the type
480 -- would likely raise Storage_Error.
482 ------------------------
483 -- Large_Storage_Type --
484 ------------------------
487 begin
488 -- The type is considered large if its bounds are known at
489 -- compile time and if it requires at least as many bits as
490 -- a Positive to store the possible values.
494 and then
499 -- Start of processing for Check_Large
501 begin
502 -- Check that the Disc has a large range
508 -- If the enclosing type is limited, we allocate only the
509 -- default value, not the maximum, and there is no need for
510 -- a warning.
516 -- Check that it is the high bound
520 then
524 -- Check the array allows a large range at this bound. First
525 -- find the array
539 -- Next, find the dimension
547 loop
556 -- Now, check the dimension has a large range
562 -- Warn about the danger
564 Error_Msg_N
574 -- Legal case is in index or discriminant constraint
577 N_Discriminant_Association)
578 then
580 Error_Msg_N
585 then
586 Error_Msg_N
592 -- Otherwise, context is an expression. It should not be within (i.e. a
593 -- subexpression of) a constraint for a component.
595 else
599 N_Subtype_Indication,
600 N_Entry_Declaration)
601 loop
607 -- If the discriminant is used in an expression that is a bound of a
608 -- scalar type, an Itype is created and the bounds are attached to
609 -- its range, not to the original subtype indication. Such use is of
610 -- course a double fault.
614 N_Derived_Type_Definition)
617 -- The constraint itself may be given by a subtype indication,
618 -- rather than by a more common discrete range.
621 and then
625 then
626 Error_Msg_N
632 --------------------------------
633 -- Check_For_Visible_Operator --
634 --------------------------------
637 begin
639 Error_Msg_NE -- CODEFIX
641 Error_Msg_N -- CODEFIX
646 ----------------------------------
647 -- Check_Fully_Declared_Prefix --
648 ----------------------------------
650 procedure Check_Fully_Declared_Prefix
653 is
654 begin
655 -- Check that the designated type of the prefix of a dereference is
656 -- not an incomplete type. This cannot be done unconditionally, because
657 -- dereferences of private types are legal in default expressions. This
658 -- case is taken care of in Check_Fully_Declared, called below. There
659 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
661 -- This consideration also applies to similar checks for allocators,
662 -- qualified expressions, and type conversions.
664 -- An additional exception concerns other per-object expressions that
665 -- are not directly related to component declarations, in particular
666 -- representation pragmas for tasks. These will be per-object
667 -- expressions if they depend on discriminants or some global entity.
668 -- If the task has access discriminants, the designated type may be
669 -- incomplete at the point the expression is resolved. This resolution
670 -- takes place within the body of the initialization procedure, where
671 -- the discriminant is replaced by its discriminal.
675 then
678 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
679 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
680 -- Analyze_Object_Renaming, and Freeze_Entity.
686 E_Incomplete_Type
688 then
690 else
695 -------------------------
696 -- Check_Ghost_Context --
697 -------------------------
701 -- Verify that the Ghost policy at the point of declaration of entity Id
702 -- matches the policy at the point of reference. If this is not the case
703 -- emit an error at Err_N.
706 -- Determine whether node Context denotes a Ghost-friendly context where
707 -- a Ghost entity can safely reside.
709 -------------------------
710 -- Is_OK_Ghost_Context --
711 -------------------------
715 -- Determine whether node Decl is a Ghost declaration or appears
716 -- within a Ghost declaration.
718 --------------------------
719 -- Is_Ghost_Declaration --
720 --------------------------
727 begin
728 -- Climb the parent chain looking for an object declaration
733 when N_Abstract_Subprogram_Declaration |
734 N_Exception_Declaration |
735 N_Exception_Renaming_Declaration |
736 N_Full_Type_Declaration |
737 N_Generic_Function_Renaming_Declaration |
738 N_Generic_Package_Declaration |
739 N_Generic_Package_Renaming_Declaration |
740 N_Generic_Procedure_Renaming_Declaration |
741 N_Generic_Subprogram_Declaration |
742 N_Number_Declaration |
743 N_Object_Declaration |
744 N_Object_Renaming_Declaration |
745 N_Package_Declaration |
746 N_Package_Renaming_Declaration |
747 N_Private_Extension_Declaration |
748 N_Private_Type_Declaration |
749 N_Subprogram_Declaration |
750 N_Subprogram_Renaming_Declaration |
751 N_Subtype_Declaration =>
758 -- Special cases
760 -- A reference to a Ghost entity may appear as the default
761 -- expression of a formal parameter of a subprogram body. This
762 -- context must be treated as suitable because the relation
763 -- between the spec and the body has not been established and
764 -- the body is not marked as Ghost yet. The real check was
765 -- performed on the spec.
769 then
772 -- References to Ghost entities may be relocated in internally
773 -- generated bodies.
777 then
780 -- The original context is an expression function that has
781 -- been split into a spec and a body. The context is OK as
782 -- long as the the initial declaration is Ghost.
785 Subp_Decl :=
793 -- Otherwise this is either an internal body or an internal
794 -- completion. Both are OK because the real check was done
795 -- before expansion activities.
800 -- Prevent the search from going too far
812 -- Start of processing for Is_OK_Ghost_Context
814 begin
815 -- The Ghost entity appears within an assertion expression
820 -- The Ghost entity is part of a declaration or its completion
825 -- The Ghost entity is referenced within a Ghost statement
830 else
835 ------------------------
836 -- Check_Ghost_Policy --
837 ------------------------
842 begin
843 -- The Ghost policy in effect a the point of declaration and at the
844 -- point of use must match (SPARK RM 6.9(14)).
862 -- Start of processing for Check_Ghost_Context
864 begin
865 -- Once it has been established that the reference to the Ghost entity
866 -- is within a suitable context, ensure that the policy at the point of
867 -- declaration and at the point of use match.
872 -- Otherwise the Ghost entity appears in a non-Ghost context and affects
873 -- its behavior or value.
875 else
876 Error_Msg_N
878 Ghost_Ref);
882 ------------------------------
883 -- Check_Infinite_Recursion --
884 ------------------------------
891 -- Check whether list of actuals is identical to list of formals of
892 -- called function (which is also the enclosing scope).
894 ------------------------
895 -- Same_Argument_List --
896 ------------------------
903 begin
906 else
915 then
926 -- Start of processing for Check_Infinite_Recursion
928 begin
929 -- Special case, if this is a procedure call and is a call to the
930 -- current procedure with the same argument list, then this is for
931 -- sure an infinite recursion and we insert a call to raise SE.
935 and then Same_Argument_List
936 then
937 declare
939 begin
943 then
955 -- If not that special case, search up tree, quitting if we reach a
956 -- construct (e.g. a conditional) that tells us that this is not a
957 -- case for an infinite recursion warning.
960 loop
963 -- If no parent, then we were not inside a subprogram, this can for
964 -- example happen when processing certain pragmas in a spec. Just
965 -- return False in this case.
971 -- Done if we get to subprogram body, this is definitely an infinite
972 -- recursion case if we did not find anything to stop us.
976 -- If appearing in conditional, result is false
979 N_And_Then,
980 N_Case_Expression,
981 N_Case_Statement,
982 N_If_Expression,
983 N_If_Statement)
984 then
989 then
990 -- If the call is the expression of a return statement and the
991 -- actuals are identical to the formals, it's worth a warning.
992 -- However, we skip this if there is an immediately preceding
993 -- raise statement, since the call is never executed.
995 -- Furthermore, this corresponds to a common idiom:
997 -- function F (L : Thing) return Boolean is
998 -- begin
999 -- raise Program_Error;
1000 -- return F (L);
1001 -- end F;
1003 -- for generating a stub function
1006 and then Same_Argument_List
1007 then
1010 -- OK, return statement is in a statement list, look for raise
1012 declare
1015 begin
1016 -- Skip past N_Freeze_Entity nodes generated by expansion
1021 loop
1025 -- If no raise statement, give warning. We look at the
1026 -- original node, because in the case of "raise ... with
1027 -- ...", the node has been transformed into a call.
1030 and then
1038 else
1050 -------------------------------
1051 -- Check_Initialization_Call --
1052 -------------------------------
1058 -- Check whether the creation of an object of the type will involve
1059 -- use of the secondary stack. If T is a record type, this is true
1060 -- if the expression for some component uses the secondary stack, e.g.
1061 -- through a call to a function that returns an unconstrained value.
1062 -- False if T is controlled, because cleanups occur elsewhere.
1064 -------------
1065 -- Uses_SS --
1066 -------------
1073 begin
1074 -- Normally we want to use the underlying type, but if it's not set
1075 -- then continue with T.
1092 then
1093 -- The expression for a dynamic component may be rewritten
1094 -- as a dereference, so retrieve original node.
1098 -- Return True if the expression is a call to a function
1099 -- (including an attribute function such as Image, or a
1100 -- user-defined operator) with a result that requires a
1101 -- transient scope.
1108 then
1121 else
1126 -- Start of processing for Check_Initialization_Call
1128 begin
1129 -- Establish a transient scope if the type needs it
1136 ---------------------------------------
1137 -- Check_No_Direct_Boolean_Operators --
1138 ---------------------------------------
1141 begin
1144 then
1145 -- Restriction only applies to original source code
1152 -- Do style check (but skip if in instance, error is on template)
1161 ------------------------------
1162 -- Check_Parameterless_Call --
1163 ------------------------------
1169 -- If the prefix is of an access_to_subprogram type, the node must be
1170 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1171 -- interpretations are access to subprograms.
1173 ---------------------------
1174 -- Prefix_Is_Access_Subp --
1175 ---------------------------
1181 begin
1182 -- If the context is an attribute reference that can apply to
1183 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1187 Name_Code_Address,
1188 Name_Access)
1189 then
1194 return
1197 else
1202 then
1213 -- Start of processing for Check_Parameterless_Call
1215 begin
1216 -- Defend against junk stuff if errors already detected
1223 then
1230 -- If the context expects a value, and the name is a procedure, this is
1231 -- most likely a missing 'Access. Don't try to resolve the parameterless
1232 -- call, error will be caught when the outer call is analyzed.
1237 and then
1239 N_Function_Call,
1240 N_Procedure_Call_Statement)
1241 then
1245 -- Rewrite as call if overloadable entity that is (or could be, in the
1246 -- overloaded case) a function call. If we know for sure that the entity
1247 -- is an enumeration literal, we do not rewrite it.
1249 -- If the entity is the name of an operator, it cannot be a call because
1250 -- operators cannot have default parameters. In this case, this must be
1251 -- a string whose contents coincide with an operator name. Set the kind
1252 -- of the node appropriately.
1260 -- Rewrite as call if it is an explicit dereference of an expression of
1261 -- a subprogram access type, and the subprogram type is not that of a
1262 -- procedure or entry.
1264 or else
1267 -- Rewrite as call if it is a selected component which is a function,
1268 -- this is the case of a call to a protected function (which may be
1269 -- overloaded with other protected operations).
1271 or else
1274 or else
1276 E_Procedure)
1279 -- If one of the above three conditions is met, rewrite as call. Apply
1280 -- the rewriting only once.
1282 then
1285 then
1287 -- This may be a prefixed call that was not fully analyzed, e.g.
1288 -- an actual in an instance.
1293 then
1301 -- The node is the name of the parameterless call. Preserve its
1302 -- descendants, which may be complex expressions.
1306 -- If overloaded, overload set belongs to new copy
1310 -- Change node to parameterless function call (note that the
1311 -- Parameter_Associations associations field is left set to Empty,
1312 -- its normal default value since there are no parameters)
1330 --------------------------------
1331 -- Is_Atomic_Ref_With_Address --
1332 --------------------------------
1337 begin
1341 else
1342 declare
1345 begin
1353 -----------------------------
1354 -- Is_Definite_Access_Type --
1355 -----------------------------
1359 begin
1365 ----------------------
1366 -- Is_Predefined_Op --
1367 ----------------------
1370 begin
1371 -- Predefined operators are intrinsic subprograms
1377 -- A call to a back-end builtin is never a predefined operator
1388 -----------------------------
1389 -- Make_Call_Into_Operator --
1390 -----------------------------
1392 procedure Make_Call_Into_Operator
1396 is
1411 -- If the operand is not universal, and the operator is given by an
1412 -- expanded name, verify that the operand has an interpretation with a
1413 -- type defined in the given scope of the operator.
1416 -- Find a type of the given class in package Pack that contains the
1417 -- operator.
1419 ---------------------------
1420 -- Operand_Type_In_Scope --
1421 ---------------------------
1428 begin
1432 else
1446 ---------------
1447 -- Type_In_P --
1448 ---------------
1454 -- Verify that node is not part of the type declaration for the
1455 -- candidate type, which would otherwise be invisible.
1457 -------------
1458 -- In_Decl --
1459 -------------
1465 begin
1474 else
1477 loop
1480 else
1489 -- Start of processing for Type_In_P
1491 begin
1492 -- If the context type is declared in the prefix package, this is the
1493 -- desired base type.
1498 else
1502 and then not In_Decl
1503 then
1514 -- Start of processing for Make_Call_Into_Operator
1516 begin
1519 -- Binary operator
1529 -- Unary operator
1531 else
1537 -- If the operator is denoted by an expanded name, and the prefix is
1538 -- not Standard, but the operator is a predefined one whose scope is
1539 -- Standard, then this is an implicit_operator, inserted as an
1540 -- interpretation by the procedure of the same name. This procedure
1541 -- overestimates the presence of implicit operators, because it does
1542 -- not examine the type of the operands. Verify now that the operand
1543 -- type appears in the given scope. If right operand is universal,
1544 -- check the other operand. In the case of concatenation, either
1545 -- argument can be the component type, so check the type of the result.
1546 -- If both arguments are literals, look for a type of the right kind
1547 -- defined in the given scope. This elaborate nonsense is brought to
1548 -- you courtesy of b33302a. The type itself must be frozen, so we must
1549 -- find the type of the proper class in the given scope.
1551 -- A final wrinkle is the multiplication operator for fixed point types,
1552 -- which is defined in Standard only, and not in the scope of the
1553 -- fixed point type itself.
1558 -- If this is a package renaming, get renamed entity, which will be
1559 -- the scope of the operands if operaton is type-correct.
1565 -- If the entity being called is defined in the given package, it is
1566 -- a renaming of a predefined operator, and known to be legal.
1570 then
1573 -- Visibility does not need to be checked in an instance: if the
1574 -- operator was not visible in the generic it has been diagnosed
1575 -- already, else there is an implicit copy of it in the instance.
1583 then
1588 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1589 -- available.
1594 then
1597 else
1606 and then Is_Binary
1608 then
1614 -- Verify that the scope contains a type that corresponds to
1615 -- the given literal. Optimize the case where Pack is Standard.
1637 else
1646 else
1655 then
1658 -- If the type is defined elsewhere, and the operator is not
1659 -- defined in the given scope (by a renaming declaration, e.g.)
1660 -- then this is an error as well. If an extension of System is
1661 -- present, and the type may be defined there, Pack must be
1662 -- System itself.
1669 then
1672 else
1678 then
1685 Error_Msg_NE
1690 -- Detect a mismatch between the context type and the result type
1691 -- in the named package, which is otherwise not detected if the
1692 -- operands are universal. Check is only needed if source entity is
1693 -- an operator, not a function that renames an operator.
1700 and then not In_Instance
1701 then
1704 then
1705 -- Already checked above
1709 -- Operator may be defined in an extension of System
1713 then
1716 else
1717 -- Could we use Wrong_Type here??? (this would require setting
1718 -- Etype (N) to the actual type found where Typ was expected).
1729 else
1733 -- If this is a call to a function that renames a predefined equality,
1734 -- the renaming declaration provides a type that must be used to
1735 -- resolve the operands. This must be done now because resolution of
1736 -- the equality node will not resolve any remaining ambiguity, and it
1737 -- assumes that the first operand is not overloaded.
1742 then
1750 -- Do rewrite setting Comes_From_Source on the result if the original
1751 -- call came from source. Although it is not strictly the case that the
1752 -- operator as such comes from the source, logically it corresponds
1753 -- exactly to the function call in the source, so it should be marked
1754 -- this way (e.g. to make sure that validity checks work fine).
1756 declare
1758 begin
1763 -- If this is an arithmetic operator and the result type is private,
1764 -- the operands and the result must be wrapped in conversion to
1765 -- expose the underlying numeric type and expand the proper checks,
1766 -- e.g. on division.
1770 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1771 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1780 else
1784 -- If in ASIS_Mode, propagate operand types to original actuals of
1785 -- function call, which would otherwise not be fully resolved. If
1786 -- the call has already been constant-folded, nothing to do. We
1787 -- relocate the operand nodes rather than copy them, to preserve
1788 -- original_node pointers, given that the operands themselves may
1789 -- have been rewritten. If the call was itself a rewriting of an
1790 -- operator node, nothing to do.
1792 if ASIS_Mode
1795 then
1796 declare
1804 begin
1809 -- If the original call has named associations, replace the
1810 -- explicit actual parameter in the association with the proper
1811 -- resolved operand.
1816 then
1819 else
1824 else
1831 then
1834 else
1839 else
1843 else
1847 else
1857 -------------------
1858 -- Operator_Kind --
1859 -------------------
1861 function Operator_Kind
1864 is
1867 begin
1868 -- Use CASE statement or array???
1905 else
1909 -- Unary operators
1911 else
1920 else
1928 ----------------------------
1929 -- Preanalyze_And_Resolve --
1930 ----------------------------
1935 begin
1939 -- Normally, we suppress all checks for this preanalysis. There is no
1940 -- point in processing them now, since they will be applied properly
1941 -- and in the proper location when the default expressions reanalyzed
1942 -- and reexpanded later on. We will also have more information at that
1943 -- point for possible suppression of individual checks.
1945 -- However, in SPARK mode, most expansion is suppressed, and this
1946 -- later reanalysis and reexpansion may not occur. SPARK mode does
1947 -- require the setting of checking flags for proof purposes, so we
1948 -- do the SPARK preanalysis without suppressing checks.
1950 -- This special handling for SPARK mode is required for example in the
1951 -- case of Ada 2012 constructs such as quantified expressions, which are
1952 -- expanded in two separate steps.
1956 else
1960 Expander_Mode_Restore;
1964 -- Version without context type
1969 begin
1976 Expander_Mode_Restore;
1980 ----------------------------------
1981 -- Replace_Actual_Discriminants --
1982 ----------------------------------
1989 -- Comment needed???
1991 -------------------
1992 -- Process_Discr --
1993 -------------------
1998 begin
2004 then
2020 -- Start of processing for Replace_Actual_Discriminants
2022 begin
2036 else
2041 -------------
2042 -- Resolve --
2043 -------------
2059 -- Determine whether a node comes from a predefined library unit or
2060 -- Standard.
2063 -- Try and fix up a literal so that it matches its expected type. New
2064 -- literals are manufactured if necessary to avoid cascaded errors.
2067 -- Additional diagnostics when an ambiguous call has an ambiguous
2068 -- argument (typically a controlling actual).
2071 -- Called when attempt at resolving current expression fails
2073 ------------------------------------
2074 -- Comes_From_Predefined_Lib_Unit --
2075 -------------------------------------
2078 begin
2079 return
2081 or else Is_Predefined_File_Name
2085 --------------------
2086 -- Patch_Up_Value --
2087 --------------------
2090 begin
2107 then
2112 Char_Literal_Value =>
2128 -------------------------------
2129 -- Report_Ambiguous_Argument --
2130 -------------------------------
2137 begin
2141 then
2144 -- Could use comments on what is going on here???
2152 else
2161 -----------------------
2162 -- Resolution_Failed --
2163 -----------------------
2166 begin
2172 -- The caller will return without calling the expander, so we need
2173 -- to set the analyzed flag. Note that it is fine to set Analyzed
2174 -- to True even if we are in the middle of a shallow analysis,
2175 -- (see the spec of sem for more details) since this is an error
2176 -- situation anyway, and there is no point in repeating the
2177 -- analysis later (indeed it won't work to repeat it later, since
2178 -- we haven't got a clear resolution of which entity is being
2179 -- referenced.)
2185 -- Start of processing for Resolve
2187 begin
2192 -- Access attribute on remote subprogram cannot be used for a non-remote
2193 -- access-to-subprogram type.
2197 Name_Unrestricted_Access,
2198 Name_Unchecked_Access)
2204 then
2205 Error_Msg_N
2211 -- If the context is a Remote_Access_To_Subprogram, access attributes
2212 -- must be resolved with the corresponding fat pointer. There is no need
2213 -- to check for the attribute name since the return type of an
2214 -- attribute is never a remote type.
2219 then
2220 declare
2228 begin
2229 -- Check that Typ is a remote access-to-subprogram type
2233 -- Prefix (N) must statically denote a remote subprogram
2234 -- declared in a package specification.
2238 Attr = Attribute_Unrestricted_Access
2239 then
2254 or else
2256 then
2258 Error_Msg_N
2260 N);
2263 -- If we are generating code in distributed mode, perform
2264 -- semantic checks against corresponding remote entities.
2266 if Expander_Active
2268 then
2269 Check_Subtype_Conformant
2271 Old_Id => Designated_Type
2297 then
2302 -- Return if already analyzed
2309 -- Any case of Any_Type as the Etype value means that we had a
2310 -- previous error.
2319 -- The resolution of an Expression_With_Actions is determined by
2320 -- its Expression.
2328 -- If not overloaded, then we know the type, and all that needs doing
2329 -- is to check that this type is compatible with the context.
2335 -- In the overloaded case, we must select the interpretation that
2336 -- is compatible with the context (i.e. the type passed to Resolve)
2338 else
2339 -- Loop through possible interpretations
2349 -- We are only interested in interpretations that are compatible
2350 -- with the expected type, any other interpretations are ignored.
2355 Write_Eol;
2358 else
2359 -- Skip the current interpretation if it is disabled by an
2360 -- abstract operator. This action is performed only when the
2361 -- type against which we are resolving is the same as the
2362 -- type of the interpretation.
2369 then
2377 -- First matching interpretation
2385 -- Matching interpretation that is not the first, maybe an
2386 -- error, but there are some cases where preference rules are
2387 -- used to choose between the two possibilities. These and
2388 -- some more obscure cases are handled in Disambiguate.
2390 else
2391 -- If the current statement is part of a predefined library
2392 -- unit, then all interpretations which come from user level
2393 -- packages should not be considered. Check previous and
2394 -- current one.
2402 -- Previous interpretation must be discarded
2412 -- Otherwise apply further disambiguation steps
2417 -- Disambiguation has succeeded. Skip the remaining
2418 -- interpretations.
2428 else
2429 -- Before we issue an ambiguity complaint, check for
2430 -- the case of a subprogram call where at least one
2431 -- of the arguments is Any_Type, and if so, suppress
2432 -- the message, since it is a cascaded error.
2435 declare
2439 begin
2451 Write_Eol;
2464 then
2469 then
2473 -- Not that special case, so issue message using the
2474 -- flag Ambiguous to control printing of the header
2475 -- message only at the start of an ambiguous set.
2480 then
2481 Error_Msg_N
2484 else
2485 Error_Msg_NE -- CODEFIX
2493 Error_Msg_N
2495 else
2496 Error_Msg_N -- CODEFIX
2502 then
2503 Report_Ambiguous_Argument;
2509 -- By default, the error message refers to the candidate
2510 -- interpretation. But if it is a predefined operator, it
2511 -- is implicitly declared at the declaration of the type
2512 -- of the operand. Recover the sloc of that declaration
2513 -- for the error message.
2519 Standard_Standard
2520 then
2525 then
2533 Standard_Standard
2534 then
2539 then
2543 -- If this is an indirect call, use the subprogram_type
2544 -- in the message, to have a meaningful location. Also
2545 -- indicate if this is an inherited operation, created
2546 -- by a type declaration.
2551 then
2553 Error_Msg_Sloc :=
2555 else
2562 then
2563 -- Special-case the message for universal_fixed
2564 -- operators, which are not declared with the type
2565 -- of the operand, but appear forever in Standard.
2569 then
2570 Error_Msg_N
2573 else
2574 Error_Msg_N
2578 elsif
2580 then
2581 Error_Msg_N
2583 else
2584 Error_Msg_N -- CODEFIX
2591 -- We have a matching interpretation, Expr_Type is the type
2592 -- from this interpretation, and Seen is the entity.
2594 -- For an operator, just set the entity name. The type will be
2595 -- set by the specific operator resolution routine.
2610 -- AI05-0139-2: Expression is overloaded because type has
2611 -- implicit dereference. If type matches context, no implicit
2612 -- dereference is involved.
2623 then
2624 -- If the node is a general indexing, the dereference is
2625 -- is inserted when resolving the rewritten form, else
2626 -- insert it now.
2630 then
2634 -- For an explicit dereference, attribute reference, range,
2635 -- short-circuit form (which is not an operator node), or call
2636 -- with a name that is an explicit dereference, there is
2637 -- nothing to be done at this point.
2640 N_Attribute_Reference,
2641 N_And_Then,
2642 N_Indexed_Component,
2643 N_Or_Else,
2644 N_Range,
2645 N_Selected_Component,
2646 N_Slice)
2648 then
2651 -- For procedure or function calls, set the type of the name,
2652 -- and also the entity pointer for the prefix.
2656 then
2663 then
2668 -- For all other cases, just set the type of the Name
2670 else
2678 -- Move to next interpretation
2686 -- At this stage Found indicates whether or not an acceptable
2687 -- interpretation exists. If not, then we have an error, except that if
2688 -- the context is Any_Type as a result of some other error, then we
2689 -- suppress the error report.
2694 -- If type we are looking for is Void, then this is the procedure
2695 -- call case, and the error is simply that what we gave is not a
2696 -- procedure name (we think of procedure calls as expressions with
2697 -- types internally, but the user doesn't think of them this way).
2701 -- Special case message if function used as a procedure
2706 then
2707 Error_Msg_NE
2711 -- Otherwise give general message (not clear what cases this
2712 -- covers, but no harm in providing for them).
2714 else
2720 -- Otherwise we do have a subexpression with the wrong type
2722 -- Check for the case of an allocator which uses an access type
2723 -- instead of the designated type. This is a common error and we
2724 -- specialize the message, posting an error on the operand of the
2725 -- allocator, complaining that we expected the designated type of
2726 -- the allocator.
2732 then
2736 -- Check for view mismatch on Null in instances, for which the
2737 -- view-swapping mechanism has no identifier.
2743 then
2748 -- Check for an aggregate. Sometimes we can get bogus aggregates
2749 -- from misuse of parentheses, and we are about to complain about
2750 -- the aggregate without even looking inside it.
2752 -- Instead, if we have an aggregate of type Any_Composite, then
2753 -- analyze and resolve the component fields, and then only issue
2754 -- another message if we get no errors doing this (otherwise
2755 -- assume that the errors in the aggregate caused the problem).
2759 then
2760 -- Disable expansion in any case. If there is a type mismatch
2761 -- it may be fatal to try to expand the aggregate. The flag
2762 -- would otherwise be set to false when the error is posted.
2766 declare
2768 -- Check one aggregate, and set Found to True if we have a
2769 -- definite error in any of its elements
2772 -- Check one element of aggregate and set Found to True if
2773 -- we definitely have an error in the element.
2775 ----------------
2776 -- Check_Aggr --
2777 ----------------
2782 begin
2795 -- If this is a default-initialized component, then
2796 -- there is nothing to check. The box will be
2797 -- replaced by the appropriate call during late
2798 -- expansion.
2809 ----------------
2810 -- Check_Elmt --
2811 ----------------
2814 begin
2815 -- If we have a nested aggregate, go inside it (to
2816 -- attempt a naked analyze-resolve of the aggregate can
2817 -- cause undesirable cascaded errors). Do not resolve
2818 -- expression if it needs a type from context, as for
2819 -- integer * fixed expression.
2824 else
2829 then
2839 begin
2844 -- Looks like we have a type error, but check for special case
2845 -- of Address wanted, integer found, with the configuration pragma
2846 -- Allow_Integer_Address active. If we have this case, introduce
2847 -- an unchecked conversion to allow the integer expression to be
2848 -- treated as an Address. The reverse case of integer wanted,
2849 -- Address found, is treated in an analogous manner.
2857 -- That special Allow_Integer_Address check did not appply, so we
2858 -- have a real type error. If an error message was issued already,
2859 -- Found got reset to True, so if it's still False, issue standard
2860 -- Wrong_Type message.
2864 declare
2867 begin
2873 -- Protected operation: retrieve operation name
2877 else
2882 Error_Msg_NE
2888 declare
2892 begin
2899 Error_Msg_NE
2905 else
2909 else
2915 Resolution_Failed;
2918 -- Test if we have more than one interpretation for the context
2921 Resolution_Failed;
2924 -- Only one intepretation
2926 else
2927 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2928 -- the "+" on T is abstract, and the operands are of universal type,
2929 -- the above code will have (incorrectly) resolved the "+" to the
2930 -- universal one in Standard. Therefore check for this case and give
2931 -- an error. We can't do this earlier, because it would cause legal
2932 -- cases to get errors (when some other type has an abstract "+").
2938 then
2943 then
2944 Error_Msg_NE
2953 -- Here we have an acceptable interpretation for the context
2955 -- Propagate type information and normalize tree for various
2956 -- predefined operations. If the context only imposes a class of
2957 -- types, rather than a specific type, propagate the actual type
2958 -- downward.
2964 Typ = Any_Discrete
2965 then
2968 -- Any_Fixed is legal in a real context only if a specific fixed-
2969 -- point type is imposed. If Norman Cohen can be confused by this,
2970 -- it deserves a separate message.
2974 then
2981 -- A user-defined operator is transformed into a function call at
2982 -- this point, so that further processing knows that operators are
2983 -- really operators (i.e. are predefined operators). User-defined
2984 -- operators that are intrinsic are just renamings of the predefined
2985 -- ones, and need not be turned into calls either, but if they rename
2986 -- a different operator, we must transform the node accordingly.
2987 -- Instantiations of Unchecked_Conversion are intrinsic but are
2988 -- treated as functions, even if given an operator designator.
2993 then
2999 and then
3001 N_Subprogram_Renaming_Declaration
3002 then
3005 -- If the node is rewritten, it will be fully resolved in
3006 -- Rewrite_Renamed_Operator.
3016 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
3018 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
3020 when N_Short_Circuit
3021 => Resolve_Short_Circuit (N, Ctx_Type);
3023 when N_Attribute_Reference
3024 => Resolve_Attribute (N, Ctx_Type);
3026 when N_Case_Expression
3027 => Resolve_Case_Expression (N, Ctx_Type);
3029 when N_Character_Literal
3030 => Resolve_Character_Literal (N, Ctx_Type);
3032 when N_Expanded_Name
3033 => Resolve_Entity_Name (N, Ctx_Type);
3035 when N_Explicit_Dereference
3036 => Resolve_Explicit_Dereference (N, Ctx_Type);
3038 when N_Expression_With_Actions
3039 => Resolve_Expression_With_Actions (N, Ctx_Type);
3041 when N_Extension_Aggregate
3042 => Resolve_Extension_Aggregate (N, Ctx_Type);
3044 when N_Function_Call
3045 => Resolve_Call (N, Ctx_Type);
3047 when N_Identifier
3048 => Resolve_Entity_Name (N, Ctx_Type);
3050 when N_If_Expression
3051 => Resolve_If_Expression (N, Ctx_Type);
3053 when N_Indexed_Component
3054 => Resolve_Indexed_Component (N, Ctx_Type);
3056 when N_Integer_Literal
3057 => Resolve_Integer_Literal (N, Ctx_Type);
3059 when N_Membership_Test
3060 => Resolve_Membership_Op (N, Ctx_Type);
3062 when N_Null => Resolve_Null (N, Ctx_Type);
3064 when N_Op_And | N_Op_Or | N_Op_Xor
3065 => Resolve_Logical_Op (N, Ctx_Type);
3067 when N_Op_Eq | N_Op_Ne
3068 => Resolve_Equality_Op (N, Ctx_Type);
3070 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
3071 => Resolve_Comparison_Op (N, Ctx_Type);
3073 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
3075 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
3076 N_Op_Divide | N_Op_Mod | N_Op_Rem
3078 => Resolve_Arithmetic_Op (N, Ctx_Type);
3080 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
3082 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
3084 when N_Op_Plus | N_Op_Minus | N_Op_Abs
3085 => Resolve_Unary_Op (N, Ctx_Type);
3087 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
3089 when N_Procedure_Call_Statement
3090 => Resolve_Call (N, Ctx_Type);
3092 when N_Operator_Symbol
3093 => Resolve_Operator_Symbol (N, Ctx_Type);
3095 when N_Qualified_Expression
3096 => Resolve_Qualified_Expression (N, Ctx_Type);
3098 -- Why is the following null, needs a comment ???
3100 when N_Quantified_Expression
3101 => null;
3103 when N_Raise_Expression
3104 => Resolve_Raise_Expression (N, Ctx_Type);
3106 when N_Raise_xxx_Error
3107 => Set_Etype (N, Ctx_Type);
3109 when N_Range => Resolve_Range (N, Ctx_Type);
3111 when N_Real_Literal
3112 => Resolve_Real_Literal (N, Ctx_Type);
3114 when N_Reference => Resolve_Reference (N, Ctx_Type);
3116 when N_Selected_Component
3117 => Resolve_Selected_Component (N, Ctx_Type);
3119 when N_Slice => Resolve_Slice (N, Ctx_Type);
3121 when N_String_Literal
3122 => Resolve_String_Literal (N, Ctx_Type);
3124 when N_Type_Conversion
3125 => Resolve_Type_Conversion (N, Ctx_Type);
3127 when N_Unchecked_Expression =>
3128 Resolve_Unchecked_Expression (N, Ctx_Type);
3130 when N_Unchecked_Type_Conversion =>
3131 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3132 end case;
3134 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3135 -- expression of an anonymous access type that occurs in the context
3136 -- of a named general access type, except when the expression is that
3137 -- of a membership test. This ensures proper legality checking in
3138 -- terms of allowed conversions (expressions that would be illegal to
3139 -- convert implicitly are allowed in membership tests).
3141 if Ada_Version >= Ada_2012
3142 and then Ekind (Ctx_Type) = E_General_Access_Type
3143 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3144 and then Nkind (Parent (N)) not in N_Membership_Test
3145 then
3146 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3147 Analyze_And_Resolve (N, Ctx_Type);
3148 end if;
3150 -- If the subexpression was replaced by a non-subexpression, then
3151 -- all we do is to expand it. The only legitimate case we know of
3152 -- is converting procedure call statement to entry call statements,
3153 -- but there may be others, so we are making this test general.
3155 if Nkind (N) not in N_Subexpr then
3156 Debug_A_Exit ("resolving ", N, " (done)");
3157 Expand (N);
3158 return;
3159 end if;
3161 -- The expression is definitely NOT overloaded at this point, so
3162 -- we reset the Is_Overloaded flag to avoid any confusion when
3163 -- reanalyzing the node.
3165 Set_Is_Overloaded (N, False);
3167 -- Freeze expression type, entity if it is a name, and designated
3168 -- type if it is an allocator (RM 13.14(10,11,13)).
3170 -- Now that the resolution of the type of the node is complete, and
3171 -- we did not detect an error, we can expand this node. We skip the
3172 -- expand call if we are in a default expression, see section
3173 -- "Handling of Default Expressions" in Sem spec.
3175 Debug_A_Exit ("resolving ", N, " (done)");
3177 -- We unconditionally freeze the expression, even if we are in
3178 -- default expression mode (the Freeze_Expression routine tests this
3179 -- flag and only freezes static types if it is set).
3181 -- Ada 2012 (AI05-177): The declaration of an expression function
3182 -- does not cause freezing, but we never reach here in that case.
3183 -- Here we are resolving the corresponding expanded body, so we do
3184 -- need to perform normal freezing.
3186 Freeze_Expression (N);
3188 -- Now we can do the expansion
3190 Expand (N);
3191 end if;
3192 end Resolve;
3194 -------------
3195 -- Resolve --
3196 -------------
3198 -- Version with check(s) suppressed
3200 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3201 begin
3202 if Suppress = All_Checks then
3203 declare
3204 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3205 begin
3206 Scope_Suppress.Suppress := (others => True);
3207 Resolve (N, Typ);
3208 Scope_Suppress.Suppress := Sva;
3209 end;
3211 else
3212 declare
3213 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3214 begin
3215 Scope_Suppress.Suppress (Suppress) := True;
3216 Resolve (N, Typ);
3217 Scope_Suppress.Suppress (Suppress) := Svg;
3218 end;
3219 end if;
3220 end Resolve;
3222 -------------
3223 -- Resolve --
3224 -------------
3226 -- Version with implicit type
3228 procedure Resolve (N : Node_Id) is
3229 begin
3230 Resolve (N, Etype (N));
3231 end Resolve;
3233 ---------------------
3234 -- Resolve_Actuals --
3235 ---------------------
3237 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3238 Loc : constant Source_Ptr := Sloc (N);
3239 A : Node_Id;
3240 A_Id : Entity_Id;
3241 A_Typ : Entity_Id;
3242 F : Entity_Id;
3243 F_Typ : Entity_Id;
3244 Prev : Node_Id := Empty;
3245 Orig_A : Node_Id;
3247 procedure Check_Aliased_Parameter;
3248 -- Check rules on aliased parameters and related accessibility rules
3249 -- in (RM 3.10.2 (10.2-10.4)).
3251 procedure Check_Argument_Order;
3252 -- Performs a check for the case where the actuals are all simple
3253 -- identifiers that correspond to the formal names, but in the wrong
3254 -- order, which is considered suspicious and cause for a warning.
3256 procedure Check_Prefixed_Call;
3257 -- If the original node is an overloaded call in prefix notation,
3259 -- Try_Object_Operation has already verified that there is a valid
3260 -- interpretation, but the form of the actual can only be determined
3261 -- once the primitive operation is identified.
3264 -- If the actual is missing in a call, insert in the actuals list
3265 -- an instance of the default expression. The insertion is always
3266 -- a named association.
3268 procedure Property_Error
3272 -- Emit an error concerning variable Var with entity Var_Id that has
3273 -- enabled property Prop_Nam when it acts as an actual parameter in a
3274 -- call and the corresponding formal parameter is of mode IN.
3277 -- Check whether T1 and T2, or their full views, are derived from a
3278 -- common type. Used to enforce the restrictions on array conversions
3279 -- of AI95-00246.
3282 -- Predicate to determine whether an actual that is a concatenation
3283 -- will be evaluated statically and does not need a transient scope.
3284 -- This must be determined before the actual is resolved and expanded
3285 -- because if needed the transient scope must be introduced earlier.
3287 ------------------------------
3288 -- Check_Aliased_Parameter --
3289 ------------------------------
3294 begin
3302 else
3309 -- In a generic body assume the worst for generic formals:
3310 -- they can have a constrained partial view (AI05-041).
3316 then
3319 else
3324 else
3336 then
3344 then
3345 Error_Msg_N
3351 --------------------------
3352 -- Check_Argument_Order --
3353 --------------------------
3356 begin
3357 -- Nothing to do if no parameters, or original node is neither a
3358 -- function call nor a procedure call statement (happens in the
3359 -- operator-transformed-to-function call case), or the call does
3360 -- not come from source, or this warning is off.
3362 if not Warn_On_Parameter_Order
3366 then
3370 declare
3373 begin
3374 -- Nothing to do if only one parameter
3380 -- Here if at least two arguments
3382 declare
3388 -- Set True if an out of order case is found
3390 begin
3391 -- Collect identifier names of actuals, fail if any actual is
3392 -- not a simple identifier, and record max length of name.
3398 else
3404 -- If we got this far, all actuals are identifiers and the list
3405 -- of their names is stored in the Actuals array.
3410 -- If we ran out of formals, that's odd, probably an error
3411 -- which will be detected elsewhere, but abandon the search.
3417 -- If name matches and is in order OK
3422 else
3423 -- If no match, see if it is elsewhere in list and if so
3424 -- flag potential wrong order if type is compatible.
3428 and then
3430 then
3436 -- No match
3444 -- If Formals left over, also probably an error, skip warning
3450 -- Here we give the warning if something was out of order
3453 Error_Msg_N
3460 -------------------------
3461 -- Check_Prefixed_Call --
3462 -------------------------
3471 begin
3472 -- Check whether the call is a prefixed call, with or without
3473 -- additional actuals.
3476 or else
3482 then
3485 then
3486 -- Introduce dereference on object in prefix
3488 New_A :=
3496 then
3497 -- Introduce an implicit 'Access in prefix
3500 Error_Msg_NE
3516 --------------------
3517 -- Insert_Default --
3518 --------------------
3524 begin
3525 -- Missing argument in call, nothing to insert
3530 else
3531 -- Note that we do a full New_Copy_Tree, so that any associated
3532 -- Itypes are properly copied. This may not be needed any more,
3533 -- but it does no harm as a safety measure. Defaults of a generic
3534 -- formal may be out of bounds of the corresponding actual (see
3535 -- cc1311b) and an additional check may be required.
3537 Actval :=
3538 New_Copy_Tree
3545 then
3551 then
3554 then
3555 -- If default is a real literal, do not introduce a
3556 -- conversion whose effect may depend on the run-time
3557 -- size of universal real.
3561 else
3572 -- Resolve aggregates with their base type, to avoid scope
3573 -- anomalies: the subtype was first built in the subprogram
3574 -- declaration, and the current call may be nested.
3578 else
3582 else
3585 -- See note above concerning aggregates
3589 then
3592 -- Resolve entities with their own type, which may differ from
3593 -- the type of a reference in a generic context (the view
3594 -- swapping mechanism did not anticipate the re-analysis of
3595 -- default values in calls).
3600 else
3605 -- If default is a tag indeterminate function call, propagate tag
3606 -- to obtain proper dispatching.
3610 then
3616 -- If the default expression raises constraint error, then just
3617 -- silently replace it with an N_Raise_Constraint_Error node, since
3618 -- we already gave the warning on the subprogram spec. If node is
3619 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3620 -- the warnings removal machinery.
3624 then
3632 Assoc :=
3637 -- Case of insertion is first named actual
3641 then
3648 else
3652 else
3656 -- Case of insertion is not first named actual
3658 else
3659 Set_Next_Named_Actual
3671 --------------------
3672 -- Property_Error --
3673 --------------------
3675 procedure Property_Error
3679 is
3680 begin
3682 Error_Msg_NE
3688 -------------------
3689 -- Same_Ancestor --
3690 -------------------
3696 begin
3699 then
3705 then
3712 --------------------------
3713 -- Static_Concatenation --
3714 --------------------------
3717 begin
3724 -- Concatenation is static when both operands are static and
3725 -- the concatenation operator is a predefined one.
3728 and then
3730 and then
3735 declare
3737 begin
3740 and then
3744 else
3750 -- Start of processing for Resolve_Actuals
3752 begin
3753 Check_Argument_Order;
3757 Check_Prefixed_Call;
3766 -- If we have an error in any actual or formal, indicated by a type
3767 -- of Any_Type, then abandon resolution attempt, and set result type
3768 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3769 -- type is imposed from context.
3773 then
3780 -- Case where actual is present
3782 -- If the actual is an entity, generate a reference to it now. We
3783 -- do this before the actual is resolved, because a formal of some
3784 -- protected subprogram, or a task discriminant, will be rewritten
3785 -- during expansion, and the source entity reference may be lost.
3790 then
3796 then
3803 -- RM 6.4.1(12): For an out parameter that is passed by
3804 -- copy, the formal parameter object is created, and:
3806 -- * For an access type, the formal parameter is initialized
3807 -- from the value of the actual, without checking that the
3808 -- value satisfies any constraint, any predicate, or any
3809 -- exclusion of the null value.
3811 -- * For a scalar type that has the Default_Value aspect
3812 -- specified, the formal parameter is initialized from the
3813 -- value of the actual, without checking that the value
3814 -- satisfies any constraint or any predicate.
3815 -- I do not understand why this case is included??? this is
3816 -- not a case where an OUT parameter is treated as IN OUT.
3818 -- * For a composite type with discriminants or that has
3819 -- implicit initial values for any subcomponents, the
3820 -- behavior is as for an in out parameter passed by copy.
3822 -- Hence for these cases we generate the read reference now
3823 -- (the write reference will be generated later by
3824 -- Note_Possible_Modification).
3827 and then
3829 or else
3831 and then
3833 or else
3836 or else Is_Partially_Initialized_Type
3838 then
3848 then
3849 -- If style checking mode on, check match of formal name
3857 -- If the formal is Out or In_Out, do not resolve and expand the
3858 -- conversion, because it is subsequently expanded into explicit
3859 -- temporaries and assignments. However, the object of the
3860 -- conversion can be resolved. An exception is the case of tagged
3861 -- type conversion with a class-wide actual. In that case we want
3862 -- the tag check to occur and no temporary will be needed (no
3863 -- representation change can occur) and the parameter is passed by
3864 -- reference, so we go ahead and resolve the type conversion.
3865 -- Another exception is the case of reference to component or
3866 -- subcomponent of a bit-packed array, in which case we want to
3867 -- defer expansion to the point the in and out assignments are
3868 -- performed.
3873 then
3876 then
3877 -- In a view conversion, the conversion must be legal in
3878 -- both directions, and thus both component types must be
3879 -- aliased, or neither (4.6 (8)).
3881 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3882 -- the privacy requirement should not apply to generic
3883 -- types, and should be checked in an instance. ARG query
3884 -- is in order ???
3888 then
3889 Error_Msg_N
3893 -- Comment here??? what set of cases???
3895 elsif
3897 then
3898 -- Check view conv between unrelated by ref array types
3902 then
3903 Error_Msg_N
3907 -- In Ada 2005 mode, check view conversion component
3908 -- type cannot be private, tagged, or volatile. Note
3909 -- that we only apply this to source conversions. The
3910 -- generated code can contain conversions which are
3911 -- not subject to this test, and we cannot extract the
3912 -- component type in such cases since it is not present.
3916 then
3917 declare
3919 Component_Type
3921 begin
3926 then
3927 Error_Msg_N
3938 -- Resolve expression if conversion is all OK
3943 then
3947 -- If the actual is a function call that returns a limited
3948 -- unconstrained object that needs finalization, create a
3949 -- transient scope for it, so that it can receive the proper
3950 -- finalization list.
3955 and then Expander_Active
3957 then
3961 -- A small optimization: if one of the actuals is a concatenation
3962 -- create a block around a procedure call to recover stack space.
3963 -- This alleviates stack usage when several procedure calls in
3964 -- the same statement list use concatenation. We do not perform
3965 -- this wrapping for code statements, where the argument is a
3966 -- static string, and we want to preserve warnings involving
3967 -- sequences of such statements.
3971 and then Expander_Active
3972 and then
3976 then
3980 else
3984 and then
3987 then
3988 Error_Msg_N
4001 -- (Ada 2005: AI-251): If the actual is an allocator whose
4002 -- directly designated type is a class-wide interface, we build
4003 -- an anonymous access type to use it as the type of the
4004 -- allocator. Later, when the subprogram call is expanded, if
4005 -- the interface has a secondary dispatch table the expander
4006 -- will add a type conversion to force the correct displacement
4007 -- of the pointer.
4010 declare
4016 begin
4019 then
4022 Set_Directly_Designated_Type
4027 -- Ada 2005, AI-162:If the actual is an allocator, the
4028 -- innermost enclosing statement is the master of the
4029 -- created object. This needs to be done with expansion
4030 -- enabled only, otherwise the transient scope will not
4031 -- be removed in the expansion of the wrapped construct.
4034 and then Expander_Active
4035 then
4045 -- (Ada 2005): The call may be to a primitive operation of a
4046 -- tagged synchronized type, declared outside of the type. In
4047 -- this case the controlling actual must be converted to its
4048 -- corresponding record type, which is the formal type. The
4049 -- actual may be a subtype, either because of a constraint or
4050 -- because it is a generic actual, so use base type to locate
4051 -- concurrent type.
4058 then
4059 -- If the actual is overloaded, look for an interpretation
4060 -- that has a synchronized type.
4065 else
4066 declare
4070 begin
4075 then
4085 declare
4088 begin
4091 else
4095 -- Tagged synchronized type (case 1): the actual is a
4096 -- concurrent type.
4100 then
4102 Unchecked_Convert_To
4106 -- Tagged synchronized type (case 2): the formal is a
4107 -- concurrent type.
4110 and then Present
4115 then
4118 -- Common case
4120 else
4125 -- Not a synchronized operation
4127 else
4135 -- An actual cannot be an untagged formal incomplete type
4140 then
4141 Error_Msg_N
4147 N_Procedure_Call_Statement)
4148 then
4149 -- In formal mode, check that actual parameters matching
4150 -- formals of tagged types are objects (or ancestor type
4151 -- conversions of objects), not general expressions.
4158 declare
4163 begin
4165 Check_SPARK_05_Restriction
4168 -- In formal mode, the only view conversions are those
4169 -- involving ancestor conversion of an extended type.
4171 elsif not
4177 then
4178 if Ekind_In
4180 then
4181 Check_SPARK_05_Restriction
4184 else
4185 Check_SPARK_05_Restriction
4189 else
4194 else
4198 -- In formal mode, the only view conversions are those
4199 -- involving ancestor conversion of an extended type.
4203 then
4204 Check_SPARK_05_Restriction
4210 -- has warnings suppressed, then we reset Never_Set_In_Source for
4211 -- the calling entity. The reason for this is to catch cases like
4212 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4213 -- uses trickery to modify an IN parameter.
4220 then
4224 -- Perform error checks for IN and IN OUT parameters
4228 -- Check unset reference. For scalar parameters, it is clearly
4229 -- wrong to pass an uninitialized value as either an IN or
4230 -- IN-OUT parameter. For composites, it is also clearly an
4231 -- error to pass a completely uninitialized value as an IN
4232 -- parameter, but the case of IN OUT is trickier. We prefer
4233 -- not to give a warning here. For example, suppose there is
4234 -- a routine that sets some component of a record to False.
4235 -- It is perfectly reasonable to make this IN-OUT and allow
4236 -- either initialized or uninitialized records to be passed
4237 -- in this case.
4239 -- For partially initialized composite values, we also avoid
4240 -- warnings, since it is quite likely that we are passing a
4241 -- partially initialized value and only the initialized fields
4242 -- will in fact be read in the subprogram.
4247 then
4251 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4252 -- actual to a nested call, since this is case of reading an
4253 -- out parameter, which is not allowed.
4258 then
4263 -- Case of OUT or IN OUT parameter
4267 -- For an Out parameter, check for useless assignment. Note
4268 -- that we can't set Last_Assignment this early, because we may
4269 -- kill current values in Resolve_Call, and that call would
4270 -- clobber the Last_Assignment field.
4272 -- Note: call Warn_On_Useless_Assignment before doing the check
4273 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4274 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4275 -- reflects the last assignment, not this one.
4282 then
4287 -- Validate the form of the actual. Note that the call to
4288 -- Is_OK_Variable_For_Out_Formal generates the required
4289 -- reference in this case.
4291 -- A call to an initialization procedure for an aggregate
4292 -- component may initialize a nested component of a constant
4293 -- designated object. In this context the object is variable.
4297 then
4301 and then
4304 then
4305 Error_Msg_N
4311 -- What's the following about???
4315 else
4316 Kill_All_Checks;
4325 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4329 -- Apply predicate tests except in certain special cases. Note
4330 -- that it might be more consistent to apply these only when
4331 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4332 -- for the outbound predicate tests ???
4338 -- Apply required constraint checks
4340 -- Gigi looks at the check flag and uses the appropriate types.
4341 -- For now since one flag is used there is an optimization
4342 -- which might not be done in the IN OUT case since Gigi does
4343 -- not do any analysis. More thought required about this ???
4345 -- In fact is this comment obsolete??? doesn't the expander now
4346 -- generate all these tests anyway???
4359 then
4362 -- For view conversions of a discriminated object, apply
4363 -- check to object itself, the conversion alreay has the
4364 -- proper type.
4368 then
4375 then
4381 then
4384 else
4388 -- Ada 2005 (AI-231): Note that the controlling parameter case
4389 -- already existed in Ada 95, which is partially checked
4390 -- elsewhere (see Checks), and we don't want the warning
4391 -- message to differ.
4396 then
4398 Apply_Compile_Time_Constraint_Error
4404 Apply_Compile_Time_Constraint_Error
4413 -- Checks for OUT parameters and IN OUT parameters
4417 -- If there is a type conversion, to make sure the return value
4418 -- meets the constraints of the variable before the conversion.
4422 Apply_Scalar_Range_Check
4424 else
4425 Apply_Range_Check
4429 -- If no conversion apply scalar range checks and length checks
4430 -- base on the subtype of the actual (NOT that of the formal).
4432 else
4437 then
4439 else
4444 -- Note: we do not apply the predicate checks for the case of
4445 -- OUT and IN OUT parameters. They are instead applied in the
4446 -- Expand_Actuals routine in Exp_Ch6.
4449 -- An actual associated with an access parameter is implicitly
4450 -- converted to the anonymous access type of the formal and must
4451 -- satisfy the legality checks for access conversions.
4455 Error_Msg_N
4459 -- If the actual is an access selected component of a variable,
4460 -- the call may modify its designated object. It is reasonable
4461 -- to treat this as a potential modification of the enclosing
4462 -- record, to prevent spurious warnings that it should be
4463 -- declared as a constant, because intuitively programmers
4464 -- regard the designated subcomponent as part of the record.
4469 then
4474 -- Check bad case of atomic/volatile argument (RM C.6(12))
4478 then
4481 then
4482 Error_Msg_NE
4488 then
4489 Error_Msg_NE
4495 -- Check that subprograms don't have improper controlling
4496 -- arguments (RM 3.9.2 (9)).
4498 -- A primitive operation may have an access parameter of an
4499 -- incomplete tagged type, but a dispatching call is illegal
4500 -- if the type is still incomplete.
4506 declare
4508 begin
4512 then
4513 Error_Msg_NE
4524 -- Apply legality rule 3.9.2 (9/1)
4529 and then not In_Instance
4530 then
4535 Error_Msg_NE
4539 -- Apply the checks described in 3.10.2(27): if the context is a
4540 -- specific access-to-object, the actual cannot be class-wide.
4541 -- Use base type to exclude access_to_subprogram cases.
4548 and then
4553 -- Disable these checks for call to imported C++ subprograms
4555 and then not
4559 then
4560 Error_Msg_N
4565 Error_Msg_NE
4570 Check_Aliased_Parameter;
4574 -- If it is a named association, treat the selector_name as a
4575 -- proper identifier, and mark the corresponding entity.
4579 -- Ignore reference in SPARK mode, as it refers to an entity not
4580 -- in scope at the point of reference, so the reference should
4581 -- be ignored for computing effects of subprograms.
4583 and then not GNATprove_Mode
4584 then
4597 -- The following checks are only relevant when SPARK_Mode is on as
4598 -- they are not standard Ada legality rule. Internally generated
4599 -- temporaries are ignored.
4604 then
4605 -- An effectively volatile object may act as an actual
4606 -- parameter when the corresponding formal is of a non-scalar
4607 -- volatile type.
4611 then
4614 -- An effectively volatile object may act as an actual
4615 -- parameter in a call to an instance of Unchecked_Conversion.
4620 else
4621 Error_Msg_N
4626 -- Detect an external variable with an enabled property that
4627 -- does not match the mode of the corresponding formal in a
4628 -- procedure call. Functions are not considered because they
4629 -- cannot have effectively volatile formal parameters in the
4630 -- first place.
4636 then
4650 then
4652 Error_Msg_NE
4656 Error_Msg_N
4662 -- A formal parameter of a specific tagged type whose related
4663 -- subprogram is subject to pragma Extensions_Visible with value
4664 -- "False" cannot act as an actual in a subprogram with value
4665 -- "True" (SPARK RM 6.1.7(3)).
4669 Extensions_Visible_True
4670 then
4671 Error_Msg_N
4674 Error_Msg_NE
4678 -- The actual parameter of a Ghost subprogram whose formal is of
4679 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(13)).
4686 then
4687 Error_Msg_NE
4693 else
4700 -- Case where actual is not present
4702 else
4703 Insert_Default;
4710 -----------------------
4711 -- Resolve_Allocator --
4712 -----------------------
4724 procedure Check_Allocator_Discrim_Accessibility
4727 -- Check that accessibility level associated with an access discriminant
4728 -- initialized in an allocator by the expression Disc_Exp is not deeper
4729 -- than the level of the allocator type Alloc_Typ. An error message is
4730 -- issued if this condition is violated. Specialized checks are done for
4731 -- the cases of a constraint expression which is an access attribute or
4732 -- an access discriminant.
4735 -- If the allocator is an actual in a call, it is allowed to be class-
4736 -- wide when the context is not because it is a controlling actual.
4738 -------------------------------------------
4739 -- Check_Allocator_Discrim_Accessibility --
4740 -------------------------------------------
4742 procedure Check_Allocator_Discrim_Accessibility
4745 is
4746 begin
4749 then
4750 Error_Msg_N
4753 -- When the expression is an Access attribute the level of the prefix
4754 -- object must not be deeper than that of the allocator's type.
4758 Attribute_Access
4761 then
4762 Error_Msg_N
4764 Disc_Exp);
4766 -- When the expression is an access discriminant the check is against
4767 -- the level of the prefix object.
4773 then
4774 Error_Msg_N
4776 Disc_Exp);
4778 -- All other cases are legal
4780 else
4785 ----------------------------
4786 -- In_Dispatching_Context --
4787 ----------------------------
4792 begin
4798 -- Start of processing for Resolve_Allocator
4800 begin
4801 -- Replace general access with specific type
4811 -- For qualified expression, resolve the expression using the given
4812 -- subtype (nothing to do for type mark, subtype indication)
4817 and then not In_Dispatching_Context
4818 then
4819 Error_Msg_N
4827 -- A qualified expression requires an exact match of the type.
4828 -- Class-wide matching is not allowed.
4833 then
4837 -- Calls to build-in-place functions are not currently supported in
4838 -- allocators for access types associated with a simple storage pool.
4839 -- Supporting such allocators may require passing additional implicit
4840 -- parameters to build-in-place functions (or a significant revision
4841 -- of the current b-i-p implementation to unify the handling for
4842 -- multiple kinds of storage pools). ???
4846 then
4847 declare
4850 begin
4852 and then
4853 Present (Get_Rep_Pragma
4855 then
4856 Error_Msg_N
4863 -- A special accessibility check is needed for allocators that
4864 -- constrain access discriminants. The level of the type of the
4865 -- expression used to constrain an access discriminant cannot be
4866 -- deeper than the type of the allocator (in contrast to access
4867 -- parameters, where the level of the actual can be arbitrary).
4869 -- We can't use Valid_Conversion to perform this check because in
4870 -- general the type of the allocator is unrelated to the type of
4871 -- the access discriminant.
4875 then
4882 then
4885 -- Get the first component expression of the aggregate
4895 else
4899 else
4918 else
4923 else
4932 -- For a subtype mark or subtype indication, freeze the subtype
4934 else
4938 Error_Msg_N
4942 -- A special accessibility check is needed for allocators that
4943 -- constrain access discriminants. The level of the type of the
4944 -- expression used to constrain an access discriminant cannot be
4945 -- deeper than the type of the allocator (in contrast to access
4946 -- parameters, where the level of the actual can be arbitrary).
4947 -- We can't use Valid_Conversion to perform this check because
4948 -- in general the type of the allocator is unrelated to the type
4949 -- of the access discriminant.
4954 then
4964 else
4978 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4979 -- check that the level of the type of the created object is not deeper
4980 -- than the level of the allocator's access type, since extensions can
4981 -- now occur at deeper levels than their ancestor types. This is a
4982 -- static accessibility level check; a run-time check is also needed in
4983 -- the case of an initialized allocator with a class-wide argument (see
4984 -- Expand_Allocator_Expression).
4988 then
4989 declare
4992 begin
4997 else
5003 then
5006 Error_Msg_N
5015 -- Do not apply Ada 2005 accessibility checks on a class-wide
5016 -- allocator if the type given in the allocator is a formal
5017 -- type. A run-time check will be performed in the instance.
5027 -- Check for allocation from an empty storage pool
5032 -- If the context is an unchecked conversion, as may happen within an
5033 -- inlined subprogram, the allocator is being resolved with its own
5034 -- anonymous type. In that case, if the target type has a specific
5035 -- storage pool, it must be inherited explicitly by the allocator type.
5039 then
5040 Set_Associated_Storage_Pool
5048 -- Check that an allocator with task parts isn't for a nested access
5049 -- type when restriction No_Task_Hierarchy applies.
5053 then
5057 -- An illegal allocator may be rewritten as a raise Program_Error
5058 -- statement.
5062 -- An anonymous access discriminant is the definition of a
5063 -- coextension.
5067 N_Discriminant_Specification
5068 then
5069 declare
5073 begin
5076 -- Ada 2012 AI05-0052: If the designated type of the allocator
5077 -- is limited, then the allocator shall not be used to define
5078 -- the value of an access discriminant unless the discriminated
5079 -- type is immutably limited.
5084 then
5085 Error_Msg_N
5091 -- Avoid marking an allocator as a dynamic coextension if it is
5092 -- within a static construct.
5098 -- Cleanup for potential static coextensions
5100 else
5106 -- Report a simple error: if the designated object is a local task,
5107 -- its body has not been seen yet, and its activation will fail an
5108 -- elaboration check.
5115 then
5121 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5122 -- type with a task component on a subpool. This action must raise
5123 -- Program_Error at runtime.
5129 then
5141 ---------------------------
5142 -- Resolve_Arithmetic_Op --
5143 ---------------------------
5145 -- Used for resolving all arithmetic operators except exponentiation
5156 -- We do the resolution using the base type, because intermediate values
5157 -- in expressions always are of the base type, not a subtype of it.
5160 -- Returns True if N is in a context that expects "any real type"
5163 -- Return True iff given type is Integer or universal real/integer
5166 -- Choose type of integer literal in fixed-point operation to conform
5167 -- to available fixed-point type. T is the type of the other operand,
5168 -- which is needed to determine the expected type of N.
5171 -- Set operand type to T if universal
5173 -------------------------------
5174 -- Expected_Type_Is_Any_Real --
5175 -------------------------------
5178 begin
5179 -- N is the expression after "delta" in a fixed_point_definition;
5180 -- see RM-3.5.9(6):
5183 N_Decimal_Fixed_Point_Definition,
5185 -- N is one of the bounds in a real_range_specification;
5186 -- see RM-3.5.7(5):
5188 N_Real_Range_Specification,
5190 -- N is the expression of a delta_constraint;
5191 -- see RM-J.3(3):
5193 N_Delta_Constraint);
5196 -----------------------------
5197 -- Is_Integer_Or_Universal --
5198 -----------------------------
5205 begin
5211 else
5217 then
5228 ----------------------------
5229 -- Set_Mixed_Mode_Operand --
5230 ----------------------------
5236 begin
5239 -- A universal integer literal is resolved as standard integer
5240 -- except in the case of a fixed-point result, where we leave it
5241 -- as universal (to be handled by Exp_Fixd later on)
5245 else
5253 then
5254 -- A universal real can appear in a fixed-type context. We resolve
5255 -- the literal with that context, even though this might raise an
5256 -- exception prematurely (the other operand may be zero).
5263 then
5264 -- Integer arg in mixed-mode operation. Resolve with universal
5265 -- type, in case preference rule must be applied.
5271 then
5272 -- Not a mixed-mode operation, resolve with context
5278 -- N may itself be a mixed-mode operation, so use context type
5285 then
5286 -- Must be (fixed * fixed) operation, operand must have one
5287 -- compatible interpretation.
5294 then
5295 -- C * F(X) in a fixed context, where C is a real literal or a
5296 -- fixed-point expression. F must have either a fixed type
5297 -- interpretation or an integer interpretation, but not both.
5304 else
5311 else
5319 -- Reanalyze the literal with the fixed type of the context. If
5320 -- context is Universal_Fixed, we are within a conversion, leave
5321 -- the literal as a universal real because there is no usable
5322 -- fixed type, and the target of the conversion plays no role in
5323 -- the resolution.
5325 declare
5329 begin
5332 else
5338 then
5340 else
5348 else
5353 ----------------------
5354 -- Set_Operand_Type --
5355 ----------------------
5358 begin
5361 then
5366 -- Start of processing for Resolve_Arithmetic_Op
5368 begin
5373 then
5377 -- Special-case for mixed-mode universal expressions or fixed point type
5378 -- operation: each argument is resolved separately. The same treatment
5379 -- is required if one of the operands of a fixed point operation is
5380 -- universal real, since in this case we don't do a conversion to a
5381 -- specific fixed-point type (instead the expander handles the case).
5383 -- Set the type of the node to its universal interpretation because
5384 -- legality checks on an exponentiation operand need the context.
5389 then
5400 or else
5403 then
5408 -- If context is a fixed type and one operand is integer, the other
5409 -- is resolved with the type of the context.
5414 then
5421 then
5425 else
5430 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5431 -- multiplying operators from being used when the expected type is
5432 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5433 -- some cases where the expected type is actually Any_Real;
5434 -- Expected_Type_Is_Any_Real takes care of that case.
5438 then
5442 N_Unchecked_Type_Conversion)
5443 then
5450 else
5453 and then not
5455 N_Unchecked_Type_Conversion)
5456 then
5457 Error_Msg_N
5462 -- The expected type is "any real type" in contexts like
5464 -- type T is delta <universal_fixed-expression> ...
5466 -- in which case we need to set the type to Universal_Real
5467 -- so that static expression evaluation will work properly.
5471 else
5481 then
5486 -- If no previous errors, this is only possible if one operand is
5487 -- overloaded and the context is universal. Resolve as such.
5492 else
5494 and then
5496 then
5500 -- If the context is Universal_Fixed and the operands are also
5501 -- universal fixed, this is an error, unless there is only one
5502 -- applicable fixed_point type (usually Duration).
5510 else
5515 else
5520 -- If one of the arguments was resolved to a non-universal type.
5521 -- label the result of the operation itself with the same type.
5522 -- Do the same for the universal argument, if any.
5534 -- In SPARK, a multiplication or division with operands of fixed point
5535 -- types must be qualified or explicitly converted to identify the
5536 -- result type.
5541 and then
5543 then
5544 Check_SPARK_05_Restriction
5548 -- Set overflow and division checking bit
5555 -- Give warning if explicit division by zero
5559 then
5565 or else
5568 then
5569 -- Specialize the warning message according to the operation.
5570 -- The following warnings are for the case
5575 -- For division, we have two cases, for float division
5576 -- of an unconstrained float type, on a machine where
5577 -- Machine_Overflows is false, we don't get an exception
5578 -- at run-time, but rather an infinity or Nan. The Nan
5579 -- case is pretty obscure, so just warn about infinities.
5583 and then not Machine_Overflows_On_Target
5584 then
5585 Error_Msg_N
5589 -- For all other cases, we get a Constraint_Error
5591 else
5592 Apply_Compile_Time_Constraint_Error
5598 Apply_Compile_Time_Constraint_Error
5603 Apply_Compile_Time_Constraint_Error
5607 -- Division by zero can only happen with division, rem,
5608 -- and mod operations.
5614 -- Otherwise just set the flag to check at run time
5616 else
5621 -- If Restriction No_Implicit_Conditionals is active, then it is
5622 -- violated if either operand can be negative for mod, or for rem
5623 -- if both operands can be negative.
5627 then
5628 declare
5635 -- Set if corresponding operand might be negative
5637 begin
5638 Determine_Range
5642 Determine_Range
5646 -- Check if we will be generating conditionals. There are two
5647 -- cases where that can happen, first for REM, the only case
5648 -- is largest negative integer mod -1, where the division can
5649 -- overflow, but we still have to give the right result. The
5650 -- front end generates a test for this annoying case. Here we
5651 -- just test if both operands can be negative (that's what the
5652 -- expander does, so we match its logic here).
5654 -- The second case is mod where either operand can be negative.
5655 -- In this case, the back end has to generate additional tests.
5658 or else
5660 then
5672 ------------------
5673 -- Resolve_Call --
5674 ------------------
5677 function Same_Or_Aliased_Subprograms
5680 -- Returns True if the subprogram entity S is the same as E or else
5681 -- S is an alias of E.
5683 ---------------------------------
5684 -- Same_Or_Aliased_Subprograms --
5685 ---------------------------------
5687 function Same_Or_Aliased_Subprograms
5690 is
5692 begin
5696 -- Local variables
5710 -- Start of processing for Resolve_Call
5712 begin
5713 -- The context imposes a unique interpretation with type Typ on a
5714 -- procedure or function call. Find the entity of the subprogram that
5715 -- yields the expected type, and propagate the corresponding formal
5716 -- constraints on the actuals. The caller has established that an
5717 -- interpretation exists, and emitted an error if not unique.
5719 -- First deal with the case of a call to an access-to-subprogram,
5720 -- dereference made explicit in Analyze_Call.
5726 else
5727 -- Find the interpretation whose type (a subprogram type) has a
5728 -- return type that is compatible with the context. Analysis of
5729 -- the node has established that one exists.
5748 -- If the prefix is not an entity, then resolve it
5754 -- For an indirect call, we always invalidate checks, since we do not
5755 -- know whether the subprogram is local or global. Yes we could do
5756 -- better here, e.g. by knowing that there are no local subprograms,
5757 -- but it does not seem worth the effort. Similarly, we kill all
5758 -- knowledge of current constant values.
5760 Kill_Current_Values;
5762 -- If this is a procedure call which is really an entry call, do
5763 -- the conversion of the procedure call to an entry call. Protected
5764 -- operations use the same circuitry because the name in the call
5765 -- can be an arbitrary expression with special resolution rules.
5770 then
5774 -- Kill checks and constant values, as above for indirect case
5775 -- Who knows what happens when another task is activated?
5777 Kill_Current_Values;
5780 -- Normal subprogram call with name established in Resolve
5786 -- Otherwise we must have the case of an overloaded call
5788 else
5791 -- Initialize Nam to prevent warning (we know it will be assigned
5792 -- in the loop below, but the compiler does not know that).
5812 then
5813 -- The prefix is a parameterless function call that returns an access
5814 -- to subprogram. If parameters are present in the current call, add
5815 -- add an explicit dereference. We use the base type here because
5816 -- within an instance these may be subtypes.
5818 -- The dereference is added either in Analyze_Call or here. Should
5819 -- be consolidated ???
5828 -- Check that a call to Current_Task does not occur in an entry body
5831 declare
5834 begin
5836 loop
5839 -- Exclude calls that occur within the default of a formal
5840 -- parameter of the entry, since those are evaluated outside
5841 -- of the body.
5848 then
5851 Error_Msg_NE
5865 -- Check that a procedure call does not occur in the context of the
5866 -- entry call statement of a conditional or timed entry call. Note that
5867 -- the case of a call to a subprogram renaming of an entry will also be
5868 -- rejected. The test for N not being an N_Entry_Call_Statement is
5869 -- defensive, covering the possibility that the processing of entry
5870 -- calls might reach this point due to later modifications of the code
5871 -- above.
5876 then
5880 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5881 -- for a procedure_or_entry_call, the procedure_name or
5882 -- procedure_prefix of the procedure_call_statement shall denote
5883 -- an entry renamed by a procedure, or (a view of) a primitive
5884 -- subprogram of a limited interface whose first parameter is
5885 -- a controlling parameter.
5890 then
5891 Error_Msg_N
5896 -- If the SPARK_05 restriction is active, we are not allowed
5897 -- to have a call to a subprogram before we see its completion.
5902 -- Don't flag strange internal calls
5907 -- Only flag calls in extended main source
5912 -- Exclude enumeration literals from this processing
5915 then
5916 Check_SPARK_05_Restriction
5920 -- Check that this is not a call to a protected procedure or entry from
5921 -- within a protected function.
5925 -- Freeze the subprogram name if not in a spec-expression. Note that
5926 -- we freeze procedure calls as well as function calls. Procedure calls
5927 -- are not frozen according to the rules (RM 13.14(14)) because it is
5928 -- impossible to have a procedure call to a non-frozen procedure in
5929 -- pure Ada, but in the code that we generate in the expander, this
5930 -- rule needs extending because we can generate procedure calls that
5931 -- need freezing.
5933 -- In Ada 2012, expression functions may be called within pre/post
5934 -- conditions of subsequent functions or expression functions. Such
5935 -- calls do not freeze when they appear within generated bodies,
5936 -- (including the body of another expression function) which would
5937 -- place the freeze node in the wrong scope. An expression function
5938 -- is frozen in the usual fashion, by the appearance of a real body,
5939 -- or at the end of a declarative part.
5943 and then
5946 then
5950 -- For a predefined operator, the type of the result is the type imposed
5951 -- by context, except for a predefined operation on universal fixed.
5952 -- Otherwise The type of the call is the type returned by the subprogram
5953 -- being called.
5960 -- If the subprogram returns an array type, and the context requires the
5961 -- component type of that array type, the node is really an indexing of
5962 -- the parameterless call. Resolve as such. A pathological case occurs
5963 -- when the type of the component is an access to the array type. In
5964 -- this case the call is truly ambiguous.
5967 and then
5970 or else
5973 and then
5975 then
5976 declare
5981 begin
5984 then
5985 Error_Msg_N
5987 else
5990 -- The called entity may be an explicit dereference, in which
5991 -- case there is no entity to set.
5999 or else
6001 and then
6003 then
6006 -- Indexed call to a parameterless function
6008 Index_Node :=
6010 Prefix =>
6013 else
6014 -- An Ada 2005 prefixed call to a primitive operation
6015 -- whose first parameter is the prefix. This prefix was
6016 -- prepended to the parameter list, which is actually a
6017 -- list of indexes. Remove the prefix in order to build
6018 -- the proper indexed component.
6020 Index_Node :=
6022 Prefix =>
6025 Parameter_Associations =>
6026 New_List
6031 -- Preserve the parenthesis count of the node
6035 -- Since we are correcting a node classification error made
6036 -- by the parser, we call Replace rather than Rewrite.
6050 else
6054 -- In the case where the call is to an overloaded subprogram, Analyze
6055 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6056 -- such a case Normalize_Actuals needs to be called once more to order
6057 -- the actuals correctly. Otherwise the call will have the ordering
6058 -- given by the last overloaded subprogram whether this is the correct
6059 -- one being called or not.
6066 -- In any case, call is fully resolved now. Reset Overload flag, to
6067 -- prevent subsequent overload resolution if node is analyzed again
6072 -- A Ghost entity must appear in a specific context
6078 -- If we are calling the current subprogram from immediately within its
6079 -- body, then that is the case where we can sometimes detect cases of
6080 -- infinite recursion statically. Do not try this in case restriction
6081 -- No_Recursion is in effect anyway, and do it only for source calls.
6086 -- Check violation of SPARK_05 restriction which does not permit
6087 -- a subprogram body to contain a call to the subprogram directly.
6091 then
6092 Check_SPARK_05_Restriction
6096 -- Issue warning for possible infinite recursion in the absence
6097 -- of the No_Recursion restriction.
6102 then
6103 -- Here we detected and flagged an infinite recursion, so we do
6104 -- not need to test the case below for further warnings. Also we
6105 -- are all done if we now have a raise SE node.
6111 -- If call is to immediately containing subprogram, then check for
6112 -- the case of a possible run-time detectable infinite recursion.
6114 else
6118 -- Although in general case, recursion is not statically
6119 -- checkable, the case of calling an immediately containing
6120 -- subprogram is easy to catch.
6124 -- If the recursive call is to a parameterless subprogram,
6125 -- then even if we can't statically detect infinite
6126 -- recursion, this is pretty suspicious, and we output a
6127 -- warning. Furthermore, we will try later to detect some
6128 -- cases here at run time by expanding checking code (see
6129 -- Detect_Infinite_Recursion in package Exp_Ch6).
6131 -- If the recursive call is within a handler, do not emit a
6132 -- warning, because this is a common idiom: loop until input
6133 -- is correct, catch illegal input in handler and restart.
6139 then
6140 -- For the case of a procedure call. We give the message
6141 -- only if the call is the first statement in a sequence
6142 -- of statements, or if all previous statements are
6143 -- simple assignments. This is simply a heuristic to
6144 -- decrease false positives, without losing too many good
6145 -- warnings. The idea is that these previous statements
6146 -- may affect global variables the procedure depends on.
6147 -- We also exclude raise statements, that may arise from
6148 -- constraint checks and are probably unrelated to the
6149 -- intended control flow.
6153 then
6154 declare
6156 begin
6160 N_Raise_Constraint_Error)
6161 then
6170 -- Do not give warning if we are in a conditional context
6172 declare
6174 begin
6180 then
6185 -- Here warning is to be issued
6201 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6205 -- If subprogram name is a predefined operator, it was given in
6206 -- functional notation. Replace call node with operator node, so
6207 -- that actuals can be resolved appropriately.
6215 then
6221 -- Create a transient scope if the resulting type requires it
6223 -- There are several notable exceptions:
6225 -- a) In init procs, the transient scope overhead is not needed, and is
6226 -- even incorrect when the call is a nested initialization call for a
6227 -- component whose expansion may generate adjust calls. However, if the
6228 -- call is some other procedure call within an initialization procedure
6229 -- (for example a call to Create_Task in the init_proc of the task
6230 -- run-time record) a transient scope must be created around this call.
6232 -- b) Enumeration literal pseudo-calls need no transient scope
6234 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6235 -- functions) do not use the secondary stack even though the return
6236 -- type may be unconstrained.
6238 -- d) Calls to a build-in-place function, since such functions may
6239 -- allocate their result directly in a target object, and cases where
6240 -- the result does get allocated in the secondary stack are checked for
6241 -- within the specialized Exp_Ch6 procedures for expanding those
6242 -- build-in-place calls.
6244 -- e) If the subprogram is marked Inline_Always, then even if it returns
6245 -- an unconstrained type the call does not require use of the secondary
6246 -- stack. However, inlining will only take place if the body to inline
6247 -- is already present. It may not be available if e.g. the subprogram is
6248 -- declared in a child instance.
6250 -- If this is an initialization call for a type whose construction
6251 -- uses the secondary stack, and it is not a nested call to initialize
6252 -- a component, we do need to create a transient scope for it. We
6253 -- check for this by traversing the type in Check_Initialization_Call.
6259 then
6265 then
6268 elsif Expander_Active
6271 and then
6273 or else
6275 then
6278 -- If the call appears within the bounds of a loop, it will
6279 -- be rewritten and reanalyzed, nothing left to do here.
6286 and then not Within_Init_Proc
6287 then
6291 -- A protected function cannot be called within the definition of the
6292 -- enclosing protected type, unless it is part of a pre/postcondition
6293 -- on another protected operation.
6298 and then not In_Spec_Expression
6299 then
6300 Error_Msg_NE
6304 -- Propagate interpretation to actuals, and add default expressions
6305 -- where needed.
6310 -- Overloaded literals are rewritten as function calls, for purpose of
6311 -- resolution. After resolution, we can replace the call with the
6312 -- literal itself.
6318 -- Avoid validation, since it is a static function call
6324 -- If the subprogram is not global, then kill all saved values and
6325 -- checks. This is a bit conservative, since in many cases we could do
6326 -- better, but it is not worth the effort. Similarly, we kill constant
6327 -- values. However we do not need to do this for internal entities
6328 -- (unless they are inherited user-defined subprograms), since they
6329 -- are not in the business of molesting local values.
6331 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6332 -- kill all checks and values for calls to global subprograms. This
6333 -- takes care of the case where an access to a local subprogram is
6334 -- taken, and could be passed directly or indirectly and then called
6335 -- from almost any context.
6337 -- Note: we do not do this step till after resolving the actuals. That
6338 -- way we still take advantage of the current value information while
6339 -- scanning the actuals.
6341 -- We suppress killing values if we are processing the nodes associated
6342 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6343 -- type kills all the values as part of analyzing the code that
6344 -- initializes the dispatch tables.
6348 or else Suppress_Value_Tracking_On_Call
6353 then
6354 Kill_Current_Values;
6357 -- If we are warning about unread OUT parameters, this is the place to
6358 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6359 -- after the above call to Kill_Current_Values (since that call clears
6360 -- the Last_Assignment field of all local variables).
6365 then
6366 declare
6370 begin
6380 then
6390 -- If the subprogram is a primitive operation, check whether or not
6391 -- it is a correct dispatching call.
6395 then
6400 and then not In_Instance
6401 then
6405 -- If this is a dispatching call, generate the appropriate reference,
6406 -- for better source navigation in GPS.
6410 then
6413 -- Normal case, not a dispatching call: generate a call reference
6415 else
6423 -- Check for violation of restriction No_Specific_Termination_Handlers
6424 -- and warn on a potentially blocking call to Abort_Task.
6428 or else
6430 then
6437 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6438 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6439 -- need to check the second argument to determine whether it is an
6440 -- absolute or relative timing event.
6445 then
6449 -- Issue an error for a call to an eliminated subprogram. This routine
6450 -- will not perform the check if the call appears within a default
6451 -- expression.
6455 -- In formal mode, the primitive operations of a tagged type or type
6456 -- extension do not include functions that return the tagged type.
6462 then
6466 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6467 -- class-wide and the call dispatches on result in a context that does
6468 -- not provide a tag, the call raises Program_Error.
6471 and then In_Instance
6476 then
6477 -- Verify that none of the formals are controlling
6479 declare
6483 begin
6505 -- Check for calling a function with OUT or IN OUT parameter when the
6506 -- calling context (us right now) is not Ada 2012, so does not allow
6507 -- OUT or IN OUT parameters in function calls.
6512 then
6517 -- Check the dimensions of the actuals in the call. For function calls,
6518 -- propagate the dimensions from the returned type to N.
6522 -- All done, evaluate call and deal with elaboration issues
6527 -- In GNATprove mode, expansion is disabled, but we want to inline some
6528 -- subprograms to facilitate formal verification. Indirect calls through
6529 -- a subprogram type or within a generic cannot be inlined. Inlining is
6530 -- performed only for calls subject to SPARK_Mode on.
6532 if GNATprove_Mode
6535 and then not Inside_A_Generic
6536 then
6543 -- Nothing to do if the subprogram is not eligible for inlining in
6544 -- GNATprove mode.
6548 then
6551 -- Calls cannot be inlined inside assertions, as GNATprove treats
6552 -- assertions as logic expressions.
6559 -- Calls cannot be inlined inside default expressions
6566 -- Inlining should not be performed during pre-analysis
6570 -- With the one-pass inlining technique, a call cannot be
6571 -- inlined if the corresponding body has not been seen yet.
6574 Error_Msg_NE
6579 -- Nothing to do if there is no body to inline, indicating that
6580 -- the subprogram is not suitable for inlining in GNATprove
6581 -- mode.
6586 -- Calls cannot be inlined inside potentially unevaluated
6587 -- expressions, as this would create complex actions inside
6588 -- expressions, that are not handled by GNATprove.
6592 Error_Msg_N
6596 -- Otherwise, inline the call
6598 else
6608 -----------------------------
6609 -- Resolve_Case_Expression --
6610 -----------------------------
6615 begin
6626 -------------------------------
6627 -- Resolve_Character_Literal --
6628 -------------------------------
6634 begin
6635 -- Verify that the character does belong to the type of the context
6640 -- Wide_Wide_Character literals must always be defined, since the set
6641 -- of wide wide character literals is complete, i.e. if a character
6642 -- literal is accepted by the parser, then it is OK for wide wide
6643 -- character (out of range character literals are rejected).
6648 -- Always accept character literal for type Any_Character, which
6649 -- occurs in error situations and in comparisons of literals, both
6650 -- of which should accept all literals.
6655 -- For Standard.Character or a type derived from it, check that the
6656 -- literal is in range.
6663 -- For Standard.Wide_Character or a type derived from it, check that the
6664 -- literal is in range.
6671 -- For Standard.Wide_Wide_Character or a type derived from it, we
6672 -- know the literal is in range, since the parser checked.
6677 -- If the entity is already set, this has already been resolved in a
6678 -- generic context, or comes from expansion. Nothing else to do.
6683 -- Otherwise we have a user defined character type, and we can use the
6684 -- standard visibility mechanisms to locate the referenced entity.
6686 else
6699 -- If we fall through, then the literal does not match any of the
6700 -- entries of the enumeration type. This isn't just a constraint error
6701 -- situation, it is an illegality (see RM 4.2).
6703 Error_Msg_NE
6707 ---------------------------
6708 -- Resolve_Comparison_Op --
6709 ---------------------------
6711 -- Context requires a boolean type, and plays no role in resolution.
6712 -- Processing identical to that for equality operators. The result type is
6713 -- the base type, which matters when pathological subtypes of booleans with
6714 -- limited ranges are used.
6721 begin
6722 -- If this is an intrinsic operation which is not predefined, use the
6723 -- types of its declared arguments to resolve the possibly overloaded
6724 -- operands. Otherwise the operands are unambiguous and specify the
6725 -- expected type.
6730 else
6741 -- Skip remaining processing if already set to Any_Type
6747 -- Deal with other error cases
6751 T = Any_Character
6752 then
6755 else
6763 -- Resolve the operands if types OK
6772 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6773 -- types or array types except String.
6776 Check_SPARK_05_Restriction
6781 then
6782 Check_SPARK_05_Restriction
6786 -- Check comparison on unordered enumeration
6790 Error_Msg_NE
6795 -- Evaluate the relation (note we do this after the above check since
6796 -- this Eval call may change N to True/False.
6802 -----------------------------------------
6803 -- Resolve_Discrete_Subtype_Indication --
6804 -----------------------------------------
6806 procedure Resolve_Discrete_Subtype_Indication
6809 is
6813 begin
6821 else
6831 Error_Msg_NE
6834 -- Rewrite the constraint as a range of Typ
6835 -- to allow compilation to proceed further.
6847 else
6851 -- Additionally, we must check that the bounds are compatible
6852 -- with the given subtype, which might be different from the
6853 -- type of the context.
6857 -- ??? If the above check statically detects a Constraint_Error
6858 -- it replaces the offending bound(s) of the range R with a
6859 -- Constraint_Error node. When the itype which uses these bounds
6860 -- is frozen the resulting call to Duplicate_Subexpr generates
6861 -- a new temporary for the bounds.
6863 -- Unfortunately there are other itypes that are also made depend
6864 -- on these bounds, so when Duplicate_Subexpr is called they get
6865 -- a forward reference to the newly created temporaries and Gigi
6866 -- aborts on such forward references. This is probably sign of a
6867 -- more fundamental problem somewhere else in either the order of
6868 -- itype freezing or the way certain itypes are constructed.
6870 -- To get around this problem we call Remove_Side_Effects right
6871 -- away if either bounds of R are a Constraint_Error.
6873 declare
6877 begin
6893 -------------------------
6894 -- Resolve_Entity_Name --
6895 -------------------------
6897 -- Used to resolve identifiers and expanded names
6900 function Is_OK_Volatile_Context
6903 -- Determine whether node Context denotes a "non-interfering context"
6904 -- (as defined in SPARK RM 7.1.3(13)) where volatile reference Obj_Ref
6905 -- can safely reside.
6907 ----------------------------
6908 -- Is_OK_Volatile_Context --
6909 ----------------------------
6911 function Is_OK_Volatile_Context
6914 is
6916 -- Determine whether an arbitrary node appears in a check node
6919 -- Determine whether an arbitrary node appears in a procedure call
6921 ------------------
6922 -- Within_Check --
6923 ------------------
6928 begin
6929 -- Climb the parent chain looking for a check node
6936 -- Prevent the search from going too far
6948 ---------------------------
6949 -- Within_Procedure_Call --
6950 ---------------------------
6955 begin
6956 -- Climb the parent chain looking for a procedure call
6963 -- Prevent the search from going too far
6975 -- Start of processing for Is_OK_Volatile_Context
6977 begin
6978 -- The volatile object appears on either side of an assignment
6983 -- The volatile object is part of the initialization expression of
6984 -- another object. Ensure that the climb of the parent chain came
6985 -- from the expression side and not from the name side.
6990 then
6993 -- The volatile object appears as an actual parameter in a call to an
6994 -- instance of Unchecked_Conversion whose result is renamed.
6999 then
7002 -- The volatile object appears as the prefix of a name occurring
7003 -- in a non-interfering context.
7006 N_Indexed_Component,
7007 N_Selected_Component,
7008 N_Slice)
7010 and then Is_OK_Volatile_Context
7013 then
7016 -- The volatile object appears as the expression of a type conversion
7017 -- occurring in a non-interfering context.
7020 N_Unchecked_Type_Conversion)
7022 and then Is_OK_Volatile_Context
7025 then
7028 -- Allow references to volatile objects in various checks. This is
7029 -- not a direct SPARK 2014 requirement.
7034 -- Assume that references to effectively volatile objects that appear
7035 -- as actual parameters in a procedure call are always legal. A full
7036 -- legality check is done when the actuals are resolved.
7041 -- Otherwise the context is not suitable for an effectively volatile
7042 -- object.
7044 else
7049 -- Local variables
7054 -- Start of processing for Resolve_Entity_Name
7056 begin
7057 -- If garbage from errors, set to Any_Type and return
7064 -- Replace named numbers by corresponding literals. Note that this is
7065 -- the one case where Resolve_Entity_Name must reset the Etype, since
7066 -- it is currently marked as universal.
7076 -- For enumeration literals, we need to make sure that a proper style
7077 -- check is done, since such literals are overloaded, and thus we did
7078 -- not do a style check during the first phase of analysis.
7084 -- Case of subtype name appearing as an operand in expression
7088 -- Allow use of subtype if it is a concurrent type where we are
7089 -- currently inside the body. This will eventually be expanded into a
7090 -- call to Self (for tasks) or _object (for protected objects). Any
7091 -- other use of a subtype is invalid.
7095 then
7098 -- Any other use is an error
7100 else
7101 Error_Msg_N
7105 -- Check discriminant use if entity is discriminant in current scope,
7106 -- i.e. discriminant of record or concurrent type currently being
7107 -- analyzed. Uses in corresponding body are unrestricted.
7112 then
7115 -- A parameterless generic function cannot appear in a context that
7116 -- requires resolution.
7127 then
7130 -- In all other cases, just do the possible static evaluation
7132 else
7133 -- A deferred constant that appears in an expression must have a
7134 -- completion, unless it has been removed by in-place expansion of
7135 -- an aggregate.
7141 and then not In_Spec_Expression
7143 then
7147 then
7149 else
7150 Error_Msg_N (
7160 -- When the entity appears in a parameter association, retrieve the
7161 -- related subprogram call.
7167 -- The following checks are only relevant when SPARK_Mode is on as they
7168 -- are not standard Ada legality rules. An effectively volatile object
7169 -- subject to enabled properties Async_Writers or Effective_Reads must
7170 -- appear in a specific context.
7178 then
7179 -- The effectively volatile objects appears in a "non-interfering
7180 -- context" as defined in SPARK RM 7.1.3(13).
7185 -- Otherwise the context causes a side effect with respect to the
7186 -- effectively volatile object.
7188 else
7189 SPARK_Msg_N
7195 -- A Ghost entity must appear in a specific context
7201 -- In SPARK mode, need to check possible elaboration issues
7208 -------------------
7209 -- Resolve_Entry --
7210 -------------------
7222 -- If the bounds of the entry family being called depend on task
7223 -- discriminants, build a new index subtype where a discriminant is
7224 -- replaced with the value of the discriminant of the target task.
7225 -- The target task is the prefix of the entry name in the call.
7227 -----------------------
7228 -- Actual_Index_Type --
7229 -----------------------
7239 -- If the bound is given by a discriminant, replace with a reference
7240 -- to the discriminant of the same name in the target task. If the
7241 -- entry name is the target of a requeue statement and the entry is
7242 -- in the current protected object, the bound to be used is the
7243 -- discriminal of the object (see Apply_Range_Checks for details of
7244 -- the transformation).
7246 -----------------------------
7247 -- Actual_Discriminant_Ref --
7248 -----------------------------
7254 begin
7259 then
7265 then
7266 -- Note: here Bound denotes a discriminant of the corresponding
7267 -- record type tskV, whose discriminal is a formal of the
7268 -- init-proc tskVIP. What we want is the body discriminal,
7269 -- which is associated to the discriminant of the original
7270 -- concurrent type tsk.
7272 return New_Occurrence_Of
7275 else
7276 Ref :=
7286 -- Start of processing for Actual_Index_Type
7288 begin
7291 then
7294 else
7308 -- Start of processing of Resolve_Entry
7310 begin
7311 -- Find name of entry being called, and resolve prefix of name with its
7312 -- own type. The prefix can be overloaded, and the name and signature of
7313 -- the entry must be taken into account.
7317 -- Case of dealing with entry family within the current tasks
7321 else
7327 -- Entry call to an entry (or entry family) in the current task. This
7328 -- is legal even though the task will deadlock. Rewrite as call to
7329 -- current task.
7331 -- This can also be a call to an entry in an enclosing task. If this
7332 -- is a single task, we have to retrieve its name, because the scope
7333 -- of the entry is the task type, not the object. If the enclosing
7334 -- task is a task type, the identity of the task is given by its own
7335 -- self variable.
7337 -- Finally this can be a requeue on an entry of the same task or
7338 -- protected object.
7345 then
7346 -- S is an enclosing task or protected object. The concurrent
7347 -- declaration has been converted into a type declaration, and
7348 -- the object itself has an object declaration that follows
7349 -- the type in the same declarative part.
7361 -- Call to current task. Will be transformed into call to Self
7368 New_N :=
7371 Selector_Name =>
7378 then
7379 -- Use the entry name (which must be unique at this point) to find
7380 -- the prefix that returns the corresponding task/protected type.
7382 declare
7388 begin
7410 -- Up to this point the expression could have been the actual in a
7411 -- simple entry call, and be given by a named association.
7415 else
7421 ------------------------
7422 -- Resolve_Entry_Call --
7423 ------------------------
7435 begin
7436 -- We kill all checks here, because it does not seem worth the effort to
7437 -- do anything better, an entry call is a big operation.
7439 Kill_All_Checks;
7441 -- Processing of the name is similar for entry calls and protected
7442 -- operation calls. Once the entity is determined, we can complete
7443 -- the resolution of the actuals.
7445 -- The selector may be overloaded, in the case of a protected object
7446 -- with overloaded functions. The type of the context is used for
7447 -- resolution.
7452 then
7453 declare
7457 begin
7476 -- Simple entry call
7484 -- Call to member of entry family
7491 -- We cannot in general check the maximum depth of protected entry calls
7492 -- at compile time. But we can tell that any protected entry call at all
7493 -- violates a specified nesting depth of zero.
7499 -- Use context type to disambiguate a protected function that can be
7500 -- called without actuals and that returns an array type, and where the
7501 -- argument list may be an indexing of the returned value.
7506 and then
7512 and then
7513 Covers
7516 then
7517 declare
7520 begin
7521 Index_Node :=
7523 Prefix =>
7527 -- Since we are correcting a node classification error made by the
7528 -- parser, we call Replace rather than Rewrite.
7541 then
7542 -- Rewrite as call to the precondition wrapper, adding the task
7543 -- object to the list of actuals. If the call is to a member of an
7544 -- entry family, include the index as well.
7546 declare
7550 begin
7559 New_Call :=
7561 Name =>
7566 -- Preanalyze and resolve new call. Current procedure is called
7567 -- from Resolve_Call, after which expansion will take place.
7574 -- The operation name may have been overloaded. Order the actuals
7575 -- according to the formals of the resolved entity, and set the return
7576 -- type to that of the operation.
7587 -- Create a call reference to the entry
7595 -- Verify that a procedure call cannot masquerade as an entry
7596 -- call where an entry call is expected.
7601 then
7606 then
7611 then
7616 -- After resolution, entry calls and protected procedure calls are
7617 -- changed into entry calls, for expansion. The structure of the node
7618 -- does not change, so it can safely be done in place. Protected
7619 -- function calls must keep their structure because they are
7620 -- subexpressions.
7624 -- A protected operation that is not a function may modify the
7625 -- corresponding object, and cannot apply to a constant. If this
7626 -- is an internal call, the prefix is the type itself.
7632 then
7633 Error_Msg_N
7635 Entry_Name);
7649 -- Protected functions can return on the secondary stack, in which
7650 -- case we must trigger the transient scope mechanism.
7652 elsif Expander_Active
7654 then
7659 -------------------------
7660 -- Resolve_Equality_Op --
7661 -------------------------
7663 -- Both arguments must have the same type, and the boolean context does
7664 -- not participate in the resolution. The first pass verifies that the
7665 -- interpretation is not ambiguous, and the type of the left argument is
7666 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7667 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7668 -- though they carry a single (universal) type. Diagnose this case here.
7676 -- The resolution rule for if expressions requires that each such must
7677 -- have a unique type. This means that if several dependent expressions
7678 -- are of a non-null anonymous access type, and the context does not
7679 -- impose an expected type (as can be the case in an equality operation)
7680 -- the expression must be rejected.
7683 -- Attempt to explain the nature of a redundant comparison with True. If
7684 -- the expression N is too complex, this routine issues a general error
7685 -- message.
7688 -- In the case of allocators and access attributes, the context must
7689 -- provide an indication of the specific access type to be used. If
7690 -- one operand is of such a "generic" access type, check whether there
7691 -- is a specific visible access type that has the same designated type.
7692 -- This is semantically dubious, and of no interest to any real code,
7693 -- but c48008a makes it all worthwhile.
7695 -------------------------
7696 -- Check_If_Expression --
7697 -------------------------
7703 begin
7710 then
7716 ------------------------
7717 -- Explain_Redundancy --
7718 ------------------------
7725 begin
7728 -- Strip the operand down to an entity
7730 loop
7733 else
7738 -- The construct denotes an entity
7743 -- Do not generate an error message when the comparison is done
7744 -- against the enumeration literal Standard.True.
7748 -- Build a customized error message
7775 -- The construct is too complex to disect, issue a general message
7777 else
7782 -----------------------------
7783 -- Find_Unique_Access_Type --
7784 -----------------------------
7791 begin
7793 E_Access_Attribute_Type)
7794 then
7798 E_Access_Attribute_Type)
7799 then
7801 else
7813 then
7826 -- Start of processing for Resolve_Equality_Op
7828 begin
7839 T = Any_Character
7840 then
7843 else
7852 then
7861 -- If expressions must have a single type, and if the context does
7862 -- not impose one the dependent expressions cannot be anonymous
7863 -- access types.
7865 -- Why no similar processing for case expressions???
7869 E_Anonymous_Access_Subprogram_Type)
7871 E_Anonymous_Access_Subprogram_Type)
7872 then
7880 -- In SPARK, equality operators = and /= for array types other than
7881 -- String are only defined when, for each index position, the
7882 -- operands have equal static bounds.
7886 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7887 -- operation if not needed.
7895 then
7896 Check_SPARK_05_Restriction
7901 -- If the unique type is a class-wide type then it will be expanded
7902 -- into a dispatching call to the predefined primitive. Therefore we
7903 -- check here for potential violation of such restriction.
7909 if Warn_On_Redundant_Constructs
7914 then
7915 Error_Msg_N -- CODEFIX
7925 -- If this is an inequality, it may be the implicit inequality
7926 -- created for a user-defined operation, in which case the corres-
7927 -- ponding equality operation is not intrinsic, and the operation
7928 -- cannot be constant-folded. Else fold.
7933 or else Is_Intrinsic_Subprogram
7935 then
7941 then
7945 -- Ada 2005: If one operand is an anonymous access type, convert the
7946 -- other operand to it, to ensure that the underlying types match in
7947 -- the back-end. Same for access_to_subprogram, and the conversion
7948 -- verifies that the types are subtype conformant.
7950 -- We apply the same conversion in the case one of the operands is a
7951 -- private subtype of the type of the other.
7953 -- Why the Expander_Active test here ???
7955 if Expander_Active
7956 and then
7958 E_Anonymous_Access_Subprogram_Type)
7960 then
7980 ----------------------------------
7981 -- Resolve_Explicit_Dereference --
7982 ----------------------------------
7990 -- The candidate prefix type, if overloaded
7995 begin
7999 -- A useful optimization: check whether the dereference denotes an
8000 -- element of a container, and if so rewrite it as a call to the
8001 -- corresponding Element function.
8003 -- Disabled for now, on advice of ARG. A more restricted form of the
8004 -- predicate might be acceptable ???
8006 -- if Is_Container_Element (N) then
8007 -- return;
8008 -- end if;
8012 -- Use the context type to select the prefix that has the correct
8013 -- designated type. Keep the first match, which will be the inner-
8014 -- most.
8021 then
8026 -- Remove access types that do not match, but preserve access
8027 -- to subprogram interpretations, in case a further dereference
8028 -- is needed (see below).
8041 else
8042 -- If no interpretation covers the designated type of the prefix,
8043 -- this is the pathological case where not all implementations of
8044 -- the prefix allow the interpretation of the node as a call. Now
8045 -- that the expected type is known, Remove other interpretations
8046 -- from prefix, rewrite it as a call, and resolve again, so that
8047 -- the proper call node is generated.
8058 New_N :=
8060 Name =>
8071 -- If not overloaded, resolve P with its own type
8073 else
8081 -- If the designated type is a packed unconstrained array type, and the
8082 -- explicit dereference is not in the context of an attribute reference,
8083 -- then we must compute and set the actual subtype, since it is needed
8084 -- by Gigi. The reason we exclude the attribute case is that this is
8085 -- handled fine by Gigi, and in fact we use such attributes to build the
8086 -- actual subtype. We also exclude generated code (which builds actual
8087 -- subtypes directly if they are needed).
8094 then
8098 -- Note: No Eval processing is required for an explicit dereference,
8099 -- because such a name can never be static.
8103 -------------------------------------
8104 -- Resolve_Expression_With_Actions --
8105 -------------------------------------
8108 begin
8111 -- If N has no actions, and its expression has been constant folded,
8112 -- then rewrite N as just its expression. Note, we can't do this in
8113 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8114 -- Expression (N) to be expanded again.
8118 then
8123 ----------------------------------
8124 -- Resolve_Generalized_Indexing --
8125 ----------------------------------
8133 begin
8134 -- In ASIS mode, propagate the information about the indices back to
8135 -- to the original indexing node. The generalized indexing is either
8136 -- a function call, or a dereference of one. The actuals include the
8137 -- prefix of the original node, which is the container expression.
8146 loop
8157 else
8163 ---------------------------
8164 -- Resolve_If_Expression --
8165 ---------------------------
8174 begin
8179 -- When the "then" expression is of a scalar subtype different from the
8180 -- result subtype, then insert a conversion to ensure the generation of
8181 -- a constraint check. The same is done for the else part below, again
8182 -- comparing subtypes rather than base types.
8186 then
8191 -- If ELSE expression present, just resolve using the determined type
8199 then
8204 -- If no ELSE expression is present, root type must be Standard.Boolean
8205 -- and we provide a Standard.True result converted to the appropriate
8206 -- Boolean type (in case it is a derived boolean type).
8209 Else_Expr :=
8214 else
8223 -------------------------------
8224 -- Resolve_Indexed_Component --
8225 -------------------------------
8233 begin
8241 -- Use the context type to select the prefix that yields the correct
8242 -- component type.
8244 declare
8251 begin
8258 and then
8259 Covers
8262 then
8271 else
8277 else
8288 else
8295 -- If prefix is access type, dereference to get real array type.
8296 -- Note: we do not apply an access check because the expander always
8297 -- introduces an explicit dereference, and the check will happen there.
8303 -- If name was overloaded, set component type correctly now
8304 -- If a misplaced call to an entry family (which has no index types)
8305 -- return. Error will be diagnosed from calling context.
8309 else
8316 -- The prefix may have resolved to a string literal, in which case its
8317 -- etype has a special representation. This is only possible currently
8318 -- if the prefix is a static concatenation, written in functional
8319 -- notation.
8324 else
8331 else
8342 -- Do not generate the warning on suspicious index if we are analyzing
8343 -- package Ada.Tags; otherwise we will report the warning with the
8344 -- Prims_Ptr field of the dispatch table.
8347 or else not
8349 Ada_Tags)
8350 then
8355 -- If the array type is atomic, and the component is not atomic, then
8356 -- this is worth a warning, since we have a situation where the access
8357 -- to the component may cause extra read/writes of the atomic array
8358 -- object, or partial word accesses, which could be unexpected.
8364 and then Has_Atomic_Components
8367 then
8375 -----------------------------
8376 -- Resolve_Integer_Literal --
8377 -----------------------------
8380 begin
8385 --------------------------------
8386 -- Resolve_Intrinsic_Operator --
8387 --------------------------------
8396 -- If the operand is a literal, it cannot be the expression in a
8397 -- conversion. Use a qualified expression instead.
8402 begin
8404 Res :=
8410 else
8417 -- Start of processing for Resolve_Intrinsic_Operator
8419 begin
8420 -- We must preserve the original entity in a generic setting, so that
8421 -- the legality of the operation can be verified in an instance.
8436 -- If the result or operand types are private, rewrite with unchecked
8437 -- conversions on the operands and the result, to expose the proper
8438 -- underlying numeric type.
8443 then
8445 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
8446 -- What on earth is this commented out fragment of code???
8450 else
8471 then
8472 -- Add explicit conversion where needed, and save interpretations in
8473 -- case operands are overloaded.
8480 else
8486 else
8496 else
8501 --------------------------------------
8502 -- Resolve_Intrinsic_Unary_Operator --
8503 --------------------------------------
8505 procedure Resolve_Intrinsic_Unary_Operator
8508 is
8513 begin
8532 else
8537 ------------------------
8538 -- Resolve_Logical_Op --
8539 ------------------------
8544 begin
8547 -- Predefined operations on scalar types yield the base type. On the
8548 -- other hand, logical operations on arrays yield the type of the
8549 -- arguments (and the context).
8553 else
8557 -- The following test is required because the operands of the operation
8558 -- may be literals, in which case the resulting type appears to be
8559 -- compatible with a signed integer type, when in fact it is compatible
8560 -- only with modular types. If the context itself is universal, the
8561 -- operation is illegal.
8569 Error_Msg_N
8577 then
8581 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8582 -- is active and the result type is standard Boolean (do not mess with
8583 -- ops that return a nonstandard Boolean type, because something strange
8584 -- is going on).
8586 -- Note: you might expect this replacement to be done during expansion,
8587 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8588 -- is used, no part of the right operand of an "and" or "or" operator
8589 -- should be executed if the left operand would short-circuit the
8590 -- evaluation of the corresponding "and then" or "or else". If we left
8591 -- the replacement to expansion time, then run-time checks associated
8592 -- with such operands would be evaluated unconditionally, due to being
8593 -- before the condition prior to the rewriting as short-circuit forms
8594 -- during expansion.
8596 if Short_Circuit_And_Or
8599 then
8607 -- Case of OR changed to OR ELSE
8609 else
8617 -- Return now, since analysis of the rewritten ops will take care of
8618 -- other reference bookkeeping and expression folding.
8633 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8634 -- only when both operands have same static lower and higher bounds. Of
8635 -- course the types have to match, so only check if operands are
8636 -- compatible and the node itself has no errors.
8640 then
8641 declare
8645 begin
8646 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8647 -- operation if not needed.
8654 then
8655 Check_SPARK_05_Restriction
8664 ---------------------------
8665 -- Resolve_Membership_Op --
8666 ---------------------------
8668 -- The context can only be a boolean type, and does not determine the
8669 -- arguments. Arguments should be unambiguous, but the preference rule for
8670 -- universal types applies.
8680 -- Analysis has determined a unique type for the left operand. Use it to
8681 -- resolve the disjuncts.
8683 ----------------------------
8684 -- Resolve_Set_Membership --
8685 ----------------------------
8691 begin
8697 -- Alternative is an expression, a range
8698 -- or a subtype mark.
8702 then
8709 -- Check for duplicates for discrete case
8712 declare
8721 begin
8722 -- Loop checking duplicates. This is quadratic, but giant sets
8723 -- are unlikely in this context so it's a reasonable choice.
8730 N_Character_Literal)
8732 then
8750 -- Start of processing for Resolve_Membership_Op
8752 begin
8758 Resolve_Set_Membership;
8762 and then
8764 or else
8767 then
8770 -- Ada 2005 (AI-251): Support the following case:
8772 -- type I is interface;
8773 -- type T is tagged ...
8775 -- function Test (O : I'Class) is
8776 -- begin
8777 -- return O in T'Class.
8778 -- end Test;
8780 -- In this case we have nothing else to do. The membership test will be
8781 -- done at run time.
8788 then
8790 else
8794 -- If mixed-mode operations are present and operands are all literal,
8795 -- the only interpretation involves Duration, which is probably not
8796 -- the intention of the programmer.
8811 then
8817 else
8822 -- Here after resolving membership operation
8830 ------------------
8831 -- Resolve_Null --
8832 ------------------
8837 begin
8838 -- Handle restriction against anonymous null access values This
8839 -- restriction can be turned off using -gnatdj.
8841 -- Ada 2005 (AI-231): Remove restriction
8844 and then not Debug_Flag_J
8847 then
8848 -- In the common case of a call which uses an explicitly null value
8849 -- for an access parameter, give specialized error message.
8852 Error_Msg_N
8855 -- Standard message for all other cases (are there any?)
8857 else
8858 Error_Msg_N
8863 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8864 -- assignment to a null-excluding object
8869 then
8871 Insert_Action
8876 else
8883 -- In a distributed context, null for a remote access to subprogram may
8884 -- need to be replaced with a special record aggregate. In this case,
8885 -- return after having done the transformation.
8890 then
8894 -- The null literal takes its type from the context
8899 -----------------------
8900 -- Resolve_Op_Concat --
8901 -----------------------
8905 -- We wish to avoid deep recursion, because concatenations are often
8906 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
8907 -- operands nonrecursively until we find something that is not a simple
8908 -- concatenation (A in this case). We resolve that, and then walk back
8909 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
8910 -- to do the rest of the work at each level. The Parent pointers allow
8911 -- us to avoid recursion, and thus avoid running out of memory. See also
8912 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
8917 begin
8918 -- The following code is equivalent to:
8920 -- Resolve_Op_Concat_First (NN, Typ);
8921 -- Resolve_Op_Concat_Arg (N, ...);
8922 -- Resolve_Op_Concat_Rest (N, Typ);
8924 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
8925 -- operand is a concatenation.
8927 -- Walk down left operands
8929 loop
8938 -- Now (given the above example) NN is A&B and Op1 is A
8940 -- First resolve Op1 ...
8944 -- ... then walk NN back up until we reach N (where we started), calling
8945 -- Resolve_Op_Concat_Rest along the way.
8947 loop
8954 Check_SPARK_05_Restriction
8959 ---------------------------
8960 -- Resolve_Op_Concat_Arg --
8961 ---------------------------
8963 procedure Resolve_Op_Concat_Arg
8968 is
8972 begin
8974 if Is_Comp
8978 then
8980 else
8984 -- If both Array & Array and Array & Component are visible, there is a
8985 -- potential ambiguity that must be reported.
8990 then
8994 -- If the operation is user-defined and not overloaded use its
8995 -- profile. The operation may be a renaming, in which case it has
8996 -- been rewritten, and we want the original profile.
9001 then
9003 Etype
9007 -- Otherwise an aggregate may match both the array type and the
9008 -- component type.
9010 else
9015 else
9019 then
9020 declare
9025 begin
9030 -- Special-case the error message when the overloading is
9031 -- caused by a function that yields an array and can be
9032 -- called without parameters.
9037 Error_Msg_NE
9039 Error_Msg_NE
9043 else
9051 or else
9053 then
9054 Error_Msg_N -- CODEFIX
9072 else
9077 else
9081 -- Concatenation is restricted in SPARK: each operand must be either a
9082 -- string literal, the name of a string constant, a static character or
9083 -- string expression, or another concatenation. Arg cannot be a
9084 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9085 -- separately on each final operand, past concatenation operations.
9089 Check_SPARK_05_Restriction
9097 then
9098 Check_SPARK_05_Restriction
9102 -- Do not issue error on an operand that is neither a character nor a
9103 -- string, as the error is issued in Resolve_Op_Concat.
9105 else
9112 -----------------------------
9113 -- Resolve_Op_Concat_First --
9114 -----------------------------
9121 begin
9122 -- The parser folds an enormous sequence of concatenations of string
9123 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9124 -- in the right operand. If the expression resolves to a predefined "&"
9125 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9126 -- we give an error. See P_Simple_Expression in Par.Ch4.
9131 then
9146 ----------------------------
9147 -- Resolve_Op_Concat_Rest --
9148 ----------------------------
9154 begin
9163 -- If this is not a static concatenation, but the result is a string
9164 -- type (and not an array of strings) ensure that static string operands
9165 -- have their subtypes properly constructed.
9169 then
9175 ----------------------
9176 -- Resolve_Op_Expon --
9177 ----------------------
9182 begin
9183 -- Catch attempts to do fixed-point exponentiation with universal
9184 -- operands, which is a case where the illegality is not caught during
9185 -- normal operator analysis. This is not done in preanalysis mode
9186 -- since the tree is not fully decorated during preanalysis.
9197 then
9207 then
9214 then
9218 -- We do the resolution using the base type, because intermediate values
9219 -- in expressions are always of the base type, not a subtype of it.
9224 -- For integer types, right argument must be in Natural range
9239 -- Evaluate the exponentiation operator for dimensioned type
9242 else
9246 -- Set overflow checking bit. Much cleverer code needed here eventually
9247 -- and perhaps the Resolve routines should be separated for the various
9248 -- arithmetic operations, since they will need different processing. ???
9257 --------------------
9258 -- Resolve_Op_Not --
9259 --------------------
9265 -- This function determines if the parent node is a boolean operator or
9266 -- operation (comparison op, membership test, or short circuit form) and
9267 -- the not in question is the left operand of this operation. Note that
9268 -- if the not is in parens, then false is returned.
9270 -----------------------
9271 -- Parent_Is_Boolean --
9272 -----------------------
9275 begin
9279 else
9281 when N_Op_And |
9282 N_Op_Eq |
9283 N_Op_Ge |
9284 N_Op_Gt |
9285 N_Op_Le |
9286 N_Op_Lt |
9287 N_Op_Ne |
9288 N_Op_Or |
9289 N_Op_Xor |
9290 N_In |
9291 N_Not_In |
9292 N_And_Then |
9293 N_Or_Else =>
9303 -- Start of processing for Resolve_Op_Not
9305 begin
9306 -- Predefined operations on scalar types yield the base type. On the
9307 -- other hand, logical operations on arrays yield the type of the
9308 -- arguments (and the context).
9312 else
9316 -- Straightforward case of incorrect arguments
9323 -- Special case of probable missing parens
9327 Error_Msg_N
9330 else
9331 Error_Msg_N
9338 -- OK resolution of NOT
9340 else
9341 -- Warn if non-boolean types involved. This is a case like not a < b
9342 -- where a and b are modular, where we will get (not a) < b and most
9343 -- likely not (a < b) was intended.
9345 if Warn_On_Questionable_Missing_Parens
9347 and then Parent_Is_Boolean
9348 then
9352 -- Warn on double negation if checking redundant constructs
9354 if Warn_On_Redundant_Constructs
9359 then
9363 -- Complete resolution and evaluation of NOT
9373 -----------------------------
9374 -- Resolve_Operator_Symbol --
9375 -----------------------------
9377 -- Nothing to be done, all resolved already
9383 begin
9387 ----------------------------------
9388 -- Resolve_Qualified_Expression --
9389 ----------------------------------
9397 begin
9400 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9401 -- operation if not needed.
9408 then
9409 Check_SPARK_05_Restriction
9413 -- A qualified expression requires an exact match of the type, class-
9414 -- wide matching is not allowed. However, if the qualifying type is
9415 -- specific and the expression has a class-wide type, it may still be
9416 -- okay, since it can be the result of the expansion of a call to a
9417 -- dispatching function, so we also have to check class-wideness of the
9418 -- type of the expression's original node.
9421 or else
9425 then
9429 -- If the target type is unconstrained, then we reset the type of the
9430 -- result from the type of the expression. For other cases, the actual
9431 -- subtype of the expression is the target type.
9435 then
9442 -- If we still have a qualified expression after the static evaluation,
9443 -- then apply a scalar range check if needed. The reason that we do this
9444 -- after the Eval call is that otherwise, the application of the range
9445 -- check may convert an illegal static expression and result in warning
9446 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9453 ------------------------------
9454 -- Resolve_Raise_Expression --
9455 ------------------------------
9458 begin
9462 else
9467 -------------------
9468 -- Resolve_Range --
9469 -------------------
9476 -- Returns True if N is of the form X'First .. X'Last where X is the
9477 -- same entity for both attributes.
9479 --------------------
9480 -- First_Last_Ref --
9481 --------------------
9487 begin
9492 then
9493 declare
9496 begin
9500 then
9509 -- Start of processing for Resolve_Range
9511 begin
9516 -- Check for inappropriate range on unordered enumeration type
9520 -- Exclude X'First .. X'Last if X is the same entity for both
9522 and then not First_Last_Ref
9523 then
9525 Error_Msg_NE
9532 -- We have to check the bounds for being within the base range as
9533 -- required for a non-static context. Normally this is automatic and
9534 -- done as part of evaluating expressions, but the N_Range node is an
9535 -- exception, since in GNAT we consider this node to be a subexpression,
9536 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9537 -- this, but that would put the test on the main evaluation path for
9538 -- expressions.
9543 -- Check for an ambiguous range over character literals. This will
9544 -- happen with a membership test involving only literals.
9552 -- If bounds are static, constant-fold them, so size computations are
9553 -- identical between front-end and back-end. Do not perform this
9554 -- transformation while analyzing generic units, as type information
9555 -- would be lost when reanalyzing the constant node in the instance.
9568 --------------------------
9569 -- Resolve_Real_Literal --
9570 --------------------------
9575 begin
9576 -- Special processing for fixed-point literals to make sure that the
9577 -- value is an exact multiple of small where this is required. We skip
9578 -- this for the universal real case, and also for generic types.
9584 then
9585 declare
9592 begin
9593 -- Case of literal is not an exact multiple of the Small
9597 -- For a source program literal for a decimal fixed-point type,
9598 -- this is statically illegal (RM 4.9(36)).
9603 then
9607 -- Generate a warning if literal from source
9610 and then Warn_On_Bad_Fixed_Value
9611 then
9612 Error_Msg_N
9614 N);
9617 -- Replace literal by a value that is the exact representation
9618 -- of a value of the type, i.e. a multiple of the small value,
9619 -- by truncation, since Machine_Rounds is false for all GNAT
9620 -- fixed-point types (RM 4.9(38)).
9630 -- In all cases, set the corresponding integer field
9636 -- Now replace the actual type by the expected type as usual
9642 -----------------------
9643 -- Resolve_Reference --
9644 -----------------------
9649 begin
9650 -- Replace general access with specific type
9658 -- If we are taking the reference of a volatile entity, then treat it as
9659 -- a potential modification of this entity. This is too conservative,
9660 -- but necessary because remove side effects can cause transformations
9661 -- of normal assignments into reference sequences that otherwise fail to
9662 -- notice the modification.
9669 --------------------------------
9670 -- Resolve_Selected_Component --
9671 --------------------------------
9686 -- Check whether this is the initialization of a component within an
9687 -- init proc (by assignment or call to another init proc). If true,
9688 -- there is no need for a discriminant check.
9690 --------------------
9691 -- Init_Component --
9692 --------------------
9695 begin
9696 return Inside_Init_Proc
9702 -- Start of processing for Resolve_Selected_Component
9704 begin
9707 -- Use the context type to select the prefix that has a selector
9708 -- of the correct name and type.
9716 else
9720 -- Locate selected component. For a private prefix the selector
9721 -- can denote a discriminant.
9725 -- The visible components of a class-wide type are those of
9726 -- the root type.
9736 then
9743 else
9747 Error_Msg_N
9752 else
9755 -- There may be an implicit dereference. Retrieve
9756 -- designated record type.
9760 else
9766 -- Resolution chooses the new interpretation.
9767 -- Find the component with the right name.
9772 loop
9789 -- There must be a legal interpretation at this point
9796 else
9797 -- Resolve prefix with its type
9802 -- Generate cross-reference. We needed to wait until full overloading
9803 -- resolution was complete to do this, since otherwise we can't tell if
9804 -- we are an lvalue or not.
9808 else
9812 -- If prefix is an access type, the node will be transformed into an
9813 -- explicit dereference during expansion. The type of the node is the
9814 -- designated type of that of the prefix.
9819 else
9823 -- Set flag for expander if discriminant check required
9830 and then not Init_Component
9831 then
9839 -- If the prefix is a record conversion, this may be a renamed
9840 -- discriminant whose bounds differ from those of the original
9841 -- one, so we must ensure that a range check is performed.
9846 then
9850 -- Note: No Eval processing is required, because the prefix is of a
9851 -- record type, or protected type, and neither can possibly be static.
9853 -- If the record type is atomic, and the component is non-atomic, then
9854 -- this is worth a warning, since we have a situation where the access
9855 -- to the component may cause extra read/writes of the atomic array
9856 -- object, or partial word accesses, both of which may be unexpected.
9862 then
9863 Error_Msg_N
9866 Error_Msg_N
9874 -------------------
9875 -- Resolve_Shift --
9876 -------------------
9883 begin
9884 -- We do the resolution using the base type, because intermediate values
9885 -- in expressions always are of the base type, not a subtype of it.
9898 ---------------------------
9899 -- Resolve_Short_Circuit --
9900 ---------------------------
9907 begin
9908 -- Ensure all actions associated with the left operand (e.g.
9909 -- finalization of transient controlled objects) are fully evaluated
9910 -- locally within an expression with actions. This is particularly
9911 -- helpful for coverage analysis. However this should not happen in
9912 -- generics.
9915 declare
9917 begin
9925 -- Set Comes_From_Source on L to preserve warnings for unset
9926 -- reference.
9935 -- Check for issuing warning for always False assert/check, this happens
9936 -- when assertions are turned off, in which case the pragma Assert/Check
9937 -- was transformed into:
9939 -- if False and then <condition> then ...
9941 -- and we detect this pattern
9943 if Warn_On_Assertion_Failure
9950 then
9951 declare
9954 begin
9955 -- Special handling of Asssert pragma
9959 then
9960 declare
9962 Original_Node
9963 (Expression
9966 begin
9967 -- Don't warn if original condition is explicit False,
9968 -- since obviously the failure is expected in this case.
9972 then
9975 -- Issue warning. We do not want the deletion of the
9976 -- IF/AND-THEN to take this message with it. We achieve this
9977 -- by making sure that the expanded code points to the Sloc
9978 -- of the expression, not the original pragma.
9980 else
9981 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
9982 -- The source location of the expression is not usually
9983 -- the best choice here. For example, it gets located on
9984 -- the last AND keyword in a chain of boolean expressiond
9985 -- AND'ed together. It is best to put the message on the
9986 -- first character of the assertion, which is the effect
9987 -- of the First_Node call here.
9989 Error_Msg_F
9991 Expression
9996 -- Similar processing for Check pragma
10000 then
10001 -- Don't want to warn if original condition is explicit False
10003 declare
10005 Original_Node
10006 (Expression
10008 begin
10011 then
10014 -- Post warning
10016 else
10017 -- Again use Error_Msg_F rather than Error_Msg_N, see
10018 -- comment above for an explanation of why we do this.
10020 Error_Msg_F
10022 Expression
10030 -- Continue with processing of short circuit
10039 -------------------
10040 -- Resolve_Slice --
10041 -------------------
10050 begin
10053 -- Use the context type to select the prefix that yields the correct
10054 -- array type.
10056 declare
10063 begin
10071 then
10079 else
10084 else
10095 else
10105 -- If the prefix is an access to an unconstrained array, we must use
10106 -- the actual subtype of the object to perform the index checks. The
10107 -- object denoted by the prefix is implicit in the node, so we build
10108 -- an explicit representation for it in order to compute the actual
10109 -- subtype.
10114 declare
10118 begin
10129 then
10132 -- If the name is a selected component that depends on discriminants,
10133 -- build an actual subtype for it. This can happen only when the name
10134 -- itself is overloaded; otherwise the actual subtype is created when
10135 -- the selected component is analyzed.
10138 and then Full_Analysis
10140 then
10141 declare
10144 begin
10149 -- Maybe this should just be "else", instead of checking for the
10150 -- specific case of slice??? This is needed for the case where the
10151 -- prefix is an Image attribute, which gets expanded to a slice, and so
10152 -- has a constrained subtype which we want to use for the slice range
10153 -- check applied below (the range check won't get done if the
10154 -- unconstrained subtype of the 'Image is used).
10160 -- Obtain the type of the array index
10164 else
10168 -- If name was overloaded, set slice type correctly now
10172 -- Handle the generation of a range check that compares the array index
10173 -- against the discrete_range. The check is not applied to internally
10174 -- built nodes associated with the expansion of dispatch tables. Check
10175 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10176 -- the unit.
10178 if Tagged_Type_Expansion
10184 then
10187 -- The discrete_range is specified by a subtype indication. Create a
10188 -- shallow copy and inherit the type, parent and source location from
10189 -- the discrete_range. This ensures that the range check is inserted
10190 -- relative to the slice and that the runtime exception points to the
10191 -- proper construct.
10200 -- The discrete_range is a regular range. Resolve the bounds and remove
10201 -- their side effects.
10203 else
10220 -- Check bad use of type with predicates
10222 declare
10225 begin
10228 then
10230 else
10235 Bad_Predicated_Subtype_Use
10240 -- Otherwise here is where we check suspicious indexes
10251 ----------------------------
10252 -- Resolve_String_Literal --
10253 ----------------------------
10264 begin
10265 -- For a string appearing in a concatenation, defer creation of the
10266 -- string_literal_subtype until the end of the resolution of the
10267 -- concatenation, because the literal may be constant-folded away. This
10268 -- is a useful optimization for long concatenation expressions.
10270 -- If the string is an aggregate built for a single character (which
10271 -- happens in a non-static context) or a is null string to which special
10272 -- checks may apply, we build the subtype. Wide strings must also get a
10273 -- string subtype if they come from a one character aggregate. Strings
10274 -- generated by attributes might be static, but it is often hard to
10275 -- determine whether the enclosing context is static, so we generate
10276 -- subtypes for them as well, thus losing some rarer optimizations ???
10277 -- Same for strings that come from a static conversion.
10279 Need_Check :=
10288 -- If the resolving type is itself a string literal subtype, we can just
10289 -- reuse it, since there is no point in creating another.
10295 and then not Need_Check
10297 N_Attribute_Reference,
10298 N_Qualified_Expression,
10299 N_Type_Conversion)
10300 then
10303 -- Do not generate a string literal subtype for the default expression
10304 -- of a formal parameter in GNATprove mode. This is because the string
10305 -- subtype is associated with the freezing actions of the subprogram,
10306 -- however freezing is disabled in GNATprove mode and as a result the
10307 -- subtype is unavailable.
10309 elsif GNATprove_Mode
10311 then
10314 -- Otherwise we must create a string literal subtype. Note that the
10315 -- whole idea of string literal subtypes is simply to avoid the need
10316 -- for building a full fledged array subtype for each literal.
10318 else
10324 or else Need_Check
10325 then
10332 then
10338 -- The validity of a null string has been checked in the call to
10339 -- Eval_String_Literal.
10344 -- Always accept string literal with component type Any_Character, which
10345 -- occurs in error situations and in comparisons of literals, both of
10346 -- which should accept all literals.
10351 -- If the type is bit-packed, then we always transform the string
10352 -- literal into a full fledged aggregate.
10357 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10359 else
10360 -- For Standard.Wide_Wide_String, or any other type whose component
10361 -- type is Standard.Wide_Wide_Character, we know that all the
10362 -- characters in the string must be acceptable, since the parser
10363 -- accepted the characters as valid character literals.
10368 -- For the case of Standard.String, or any other type whose component
10369 -- type is Standard.Character, we must make sure that there are no
10370 -- wide characters in the string, i.e. that it is entirely composed
10371 -- of characters in range of type Character.
10373 -- If the string literal is the result of a static concatenation, the
10374 -- test has already been performed on the components, and need not be
10375 -- repeated.
10379 then
10383 -- If we are out of range, post error. This is one of the
10384 -- very few places that we place the flag in the middle of
10385 -- a token, right under the offending wide character. Not
10386 -- quite clear if this is right wrt wide character encoding
10387 -- sequences, but it's only an error message.
10389 Error_Msg
10396 -- For the case of Standard.Wide_String, or any other type whose
10397 -- component type is Standard.Wide_Character, we must make sure that
10398 -- there are no wide characters in the string, i.e. that it is
10399 -- entirely composed of characters in range of type Wide_Character.
10401 -- If the string literal is the result of a static concatenation,
10402 -- the test has already been performed on the components, and need
10403 -- not be repeated.
10407 then
10411 -- If we are out of range, post error. This is one of the
10412 -- very few places that we place the flag in the middle of
10413 -- a token, right under the offending wide character.
10415 -- This is not quite right, because characters in general
10416 -- will take more than one character position ???
10418 Error_Msg
10425 -- If the root type is not a standard character, then we will convert
10426 -- the string into an aggregate and will let the aggregate code do
10427 -- the checking. Standard Wide_Wide_Character is also OK here.
10429 else
10433 -- See if the component type of the array corresponding to the string
10434 -- has compile time known bounds. If yes we can directly check
10435 -- whether the evaluation of the string will raise constraint error.
10436 -- Otherwise we need to transform the string literal into the
10437 -- corresponding character aggregate and let the aggregate code do
10438 -- the checking.
10442 -- Check for the case of full range, where we are definitely OK
10448 -- Here the range is not the complete base type range, so check
10450 declare
10458 begin
10461 then
10467 then
10468 Apply_Compile_Time_Constraint_Error
10470 CE_Range_Check_Failed,
10481 -- If we got here we meed to transform the string literal into the
10482 -- equivalent qualified positional array aggregate. This is rather
10483 -- heavy artillery for this situation, but it is hard work to avoid.
10485 declare
10490 begin
10491 -- Build the character literals, we give them source locations that
10492 -- correspond to the string positions, which is a bit tricky given
10493 -- the possible presence of wide character escape sequences.
10507 -- Should we have a call to Skip_Wide here ???
10509 -- ??? else
10510 -- Skip_Wide (P);
10518 Expression =>
10525 -----------------------------
10526 -- Resolve_Type_Conversion --
10527 -----------------------------
10539 -- Set to False to suppress cases where we want to suppress the test
10540 -- for redundancy to avoid possible false positives on this warning.
10542 begin
10543 if not Conv_OK
10545 then
10549 -- If the Operand Etype is Universal_Fixed, then the conversion is
10550 -- never redundant. We need this check because by the time we have
10551 -- finished the rather complex transformation, the conversion looks
10552 -- redundant when it is not.
10557 -- If the operand is marked as Any_Fixed, then special processing is
10558 -- required. This is also a case where we suppress the test for a
10559 -- redundant conversion, since most certainly it is not redundant.
10564 -- Mixed-mode operation involving a literal. Context must be a fixed
10565 -- type which is applied to the literal subsequently.
10573 or else
10575 then
10576 -- Return if expression is ambiguous
10581 -- If nothing else, the available fixed type is Duration
10583 else
10587 -- Resolve the real operand with largest available precision
10591 else
10597 -- If the operand is a literal (it could be a non-static and
10598 -- illegal exponentiation) check whether the use of Duration
10599 -- is potentially inaccurate.
10604 then
10605 Error_Msg_N
10608 Error_Msg_N
10615 then
10618 else
10627 -- In SPARK, a type conversion between array types should be restricted
10628 -- to types which have matching static bounds.
10630 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10631 -- operation if not needed.
10638 then
10639 Check_SPARK_05_Restriction
10643 -- In formal mode, the operand of an ancestor type conversion must be an
10644 -- object (not an expression).
10652 then
10658 -- Note: we do the Eval_Type_Conversion call before applying the
10659 -- required checks for a subtype conversion. This is important, since
10660 -- both are prepared under certain circumstances to change the type
10661 -- conversion to a constraint error node, but in the case of
10662 -- Eval_Type_Conversion this may reflect an illegality in the static
10663 -- case, and we would miss the illegality (getting only a warning
10664 -- message), if we applied the type conversion checks first.
10668 -- Even when evaluation is not possible, we may be able to simplify the
10669 -- conversion or its expression. This needs to be done before applying
10670 -- checks, since otherwise the checks may use the original expression
10671 -- and defeat the simplifications. This is specifically the case for
10672 -- elimination of the floating-point Truncation attribute in
10673 -- float-to-int conversions.
10677 -- If after evaluation we still have a type conversion, then we may need
10678 -- to apply checks required for a subtype conversion.
10680 -- Skip these type conversion checks if universal fixed operands
10681 -- operands involved, since range checks are handled separately for
10682 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10688 then
10692 -- Issue warning for conversion of simple object to its own type. We
10693 -- have to test the original nodes, since they may have been rewritten
10694 -- by various optimizations.
10698 -- Here we test for a redundant conversion if the warning mode is
10699 -- active (and was not locally reset), and we have a type conversion
10700 -- from source not appearing in a generic instance.
10702 if Test_Redundant
10705 and then not In_Instance
10706 then
10710 -- If the node is part of a larger expression, the Target_Type
10711 -- may not be the original type of the node if the context is a
10712 -- condition. Recover original type to see if conversion is needed.
10716 then
10720 -- If we have an entity name, then give the warning if the entity
10721 -- is the right type, or if it is a loop parameter covered by the
10722 -- original type (that's needed because loop parameters have an
10723 -- odd subtype coming from the bounds).
10726 and then
10728 or else
10732 -- If not an entity, then type of expression must match
10735 then
10736 -- One more check, do not give warning if the analyzed conversion
10737 -- has an expression with non-static bounds, and the bounds of the
10738 -- target are static. This avoids junk warnings in cases where the
10739 -- conversion is necessary to establish staticness, for example in
10740 -- a case statement.
10744 then
10747 -- Finally, if this type conversion occurs in a context requiring
10748 -- a prefix, and the expression is a qualified expression then the
10749 -- type conversion is not redundant, since a qualified expression
10750 -- is not a prefix, whereas a type conversion is. For example, "X
10751 -- := T'(Funx(...)).Y;" is illegal because a selected component
10752 -- requires a prefix, but a type conversion makes it legal: "X :=
10753 -- T(T'(Funx(...))).Y;"
10755 -- In Ada 2012, a qualified expression is a name, so this idiom is
10756 -- no longer needed, but we still suppress the warning because it
10757 -- seems unfriendly for warnings to pop up when you switch to the
10758 -- newer language version.
10762 N_Indexed_Component,
10763 N_Selected_Component,
10764 N_Slice,
10765 N_Explicit_Dereference)
10766 then
10769 -- Never warn on conversion to Long_Long_Integer'Base since
10770 -- that is most likely an artifact of the extended overflow
10771 -- checking and comes from complex expanded code.
10776 -- Here we give the redundant conversion warning. If it is an
10777 -- entity, give the name of the entity in the message. If not,
10778 -- just mention the expression.
10780 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10782 else
10785 Error_Msg_NE -- CODEFIX
10788 else
10789 Error_Msg_NE
10797 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10798 -- No need to perform any interface conversion if the type of the
10799 -- expression coincides with the target type.
10802 and then Expander_Active
10804 then
10805 declare
10809 begin
10810 -- If the type of the operand is a limited view, use the non-
10811 -- limited view when available.
10816 then
10832 -- Conversion from interface type
10836 -- Ada 2005 (AI-217): Handle entities from limited views
10840 Error_Msg_NE -- CODEFIX
10843 Error_Msg_N
10845 N);
10848 and then not
10851 then
10853 Error_Msg_NE -- CODEFIX
10856 Error_Msg_N
10858 N);
10860 else
10864 -- Conversion to interface type
10868 -- Handle subtypes
10875 or else Interface_Present_In_Ancestor
10878 then
10880 else
10883 Error_Msg_N
10891 -- Ada 2012: if target type has predicates, the result requires a
10892 -- predicate check. If the context is a call to another predicate
10893 -- check we must prevent infinite recursion.
10899 or else
10901 then
10904 else
10909 -- If at this stage we have a real to integer conversion, make sure
10910 -- that the Do_Range_Check flag is set, because such conversions in
10911 -- general need a range check. We only need this if expansion is off
10912 -- or we are in GNATProve mode.
10918 then
10923 ----------------------
10924 -- Resolve_Unary_Op --
10925 ----------------------
10934 begin
10937 Check_SPARK_05_Restriction
10941 -- Deal with intrinsic unary operators
10947 then
10952 -- Deal with universal cases
10955 or else
10957 then
10964 -- Generate warning for expressions like abs (x mod 2)
10966 if Warn_On_Redundant_Constructs
10968 then
10972 Error_Msg_N -- CODEFIX
10977 -- Deal with reference generation
10984 -- Set overflow checking bit. Much cleverer code needed here eventually
10985 -- and perhaps the Resolve routines should be separated for the various
10986 -- arithmetic operations, since they will need different processing ???
10994 -- Generate warning for expressions like -5 mod 3 for integers. No need
10995 -- to worry in the floating-point case, since parens do not affect the
10996 -- result so there is no point in giving in a warning.
10998 declare
11007 begin
11008 if Warn_On_Questionable_Missing_Parens
11012 then
11015 -- We are looking for cases where the right operand is not
11016 -- parenthesized, and is a binary operator, multiply, divide, or
11017 -- mod. These are the cases where the grouping can affect results.
11021 then
11022 -- For mod, we always give the warning, since the value is
11023 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11024 -- -(5 mod 315)). But for the other cases, the only concern is
11025 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11026 -- overflows, but (-2) * 64 does not). So we try to give the
11027 -- message only when overflow is possible.
11031 then
11036 else
11042 else
11046 -- Note that the test below is deliberately excluding the
11047 -- largest negative number, since that is a potentially
11048 -- troublesome case (e.g. -2 * x, where the result is the
11049 -- largest negative integer has an overflow with 2 * x).
11056 -- For the multiplication case, the only case we have to worry
11057 -- about is when (-a)*b is exactly the largest negative number
11058 -- so that -(a*b) can cause overflow. This can only happen if
11059 -- a is a power of 2, and more generally if any operand is a
11060 -- constant that is not a power of 2, then the parentheses
11061 -- cannot affect whether overflow occurs. We only bother to
11062 -- test the left most operand
11064 -- Loop looking at left operands for one that has known value
11071 -- Operand value of 0 or 1 skips warning
11076 -- Otherwise check power of 2, if power of 2, warn, if
11077 -- anything else, skip warning.
11079 else
11083 else
11092 -- Keep looking at left operands
11097 -- For rem or "/" we can only have a problematic situation
11098 -- if the divisor has a value of minus one or one. Otherwise
11099 -- overflow is impossible (divisor > 1) or we have a case of
11100 -- division by zero in any case.
11105 then
11109 -- If we fall through warning should be issued
11111 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11113 Error_Msg_N
11120 ----------------------------------
11121 -- Resolve_Unchecked_Expression --
11122 ----------------------------------
11124 procedure Resolve_Unchecked_Expression
11127 is
11128 begin
11133 ---------------------------------------
11134 -- Resolve_Unchecked_Type_Conversion --
11135 ---------------------------------------
11137 procedure Resolve_Unchecked_Type_Conversion
11140 is
11146 begin
11147 -- Resolve operand using its own type
11151 -- In an inlined context, the unchecked conversion may be applied
11152 -- to a literal, in which case its type is the type of the context.
11153 -- (In other contexts conversions cannot apply to literals).
11155 if In_Inlined_Body
11159 then
11167 ------------------------------
11168 -- Rewrite_Operator_As_Call --
11169 ------------------------------
11176 begin
11183 New_N :=
11194 ------------------------------
11195 -- Rewrite_Renamed_Operator --
11196 ------------------------------
11198 procedure Rewrite_Renamed_Operator
11202 is
11207 begin
11208 -- Do not perform this transformation within a pre/postcondition,
11209 -- because the expression will be re-analyzed, and the transformation
11210 -- might affect the visibility of the operator, e.g. in an instance.
11216 -- Rewrite the operator node using the real operator, not its renaming.
11217 -- Exclude user-defined intrinsic operations of the same name, which are
11218 -- treated separately and rewritten as calls.
11227 -- Indicate that both the original entity and its renaming are
11228 -- referenced at this point.
11239 -- If the context type is private, add the appropriate conversions so
11240 -- that the operator is applied to the full view. This is done in the
11241 -- routines that resolve intrinsic operators.
11245 then
11247 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
11248 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
11261 -- Operator renames a user-defined operator of the same name. Use the
11262 -- original operator in the node, which is the one Gigi knows about.
11269 -----------------------
11270 -- Set_Slice_Subtype --
11271 -----------------------
11273 -- Build an implicit subtype declaration to represent the type delivered by
11274 -- the slice. This is an abbreviated version of an array subtype. We define
11275 -- an index subtype for the slice, using either the subtype name or the
11276 -- discrete range of the slice. To be consistent with index usage elsewhere
11277 -- we create a list header to hold the single index. This list is not
11278 -- otherwise attached to the syntax tree.
11289 begin
11295 else
11296 -- We force the evaluation of a range. This is definitely needed in
11297 -- the renamed case, and seems safer to do unconditionally. Note in
11298 -- any case that since we will create and insert an Itype referring
11299 -- to this range, we must make sure any side effect removal actions
11300 -- are inserted before the Itype definition.
11306 -- If the discrete range is given by a subtype indication, the
11307 -- type of the slice is the base of the subtype mark.
11310 declare
11312 begin
11321 -- Take a new copy of Drange (where bounds have been rewritten to
11322 -- reference side-effect-free names). Using a separate tree ensures
11323 -- that further expansion (e.g. while rewriting a slice assignment
11324 -- into a FOR loop) does not attempt to remove side effects on the
11325 -- bounds again (which would cause the bounds in the index subtype
11326 -- definition to refer to temporaries before they are defined) (the
11327 -- reason is that some names are considered side effect free here
11328 -- for the subtype, but not in the context of a loop iteration
11329 -- scheme).
11350 -- The Etype of the existing Slice node is reset to this slice subtype.
11351 -- Its bounds are obtained from its first index.
11355 -- For packed slice subtypes, freeze immediately (except in the case of
11356 -- being in a "spec expression" where we never freeze when we first see
11357 -- the expression).
11362 -- For all other cases insert an itype reference in the slice's actions
11363 -- so that the itype is frozen at the proper place in the tree (i.e. at
11364 -- the point where actions for the slice are analyzed). Note that this
11365 -- is different from freezing the itype immediately, which might be
11366 -- premature (e.g. if the slice is within a transient scope). This needs
11367 -- to be done only if expansion is enabled.
11374 --------------------------------
11375 -- Set_String_Literal_Subtype --
11376 --------------------------------
11384 begin
11396 -- The low bound is set from the low bound of the corresponding index
11397 -- type. Note that we do not store the high bound in the string literal
11398 -- subtype, but it can be deduced if necessary from the length and the
11399 -- low bound.
11404 -- If the lower bound is not static we create a range for the string
11405 -- literal, using the index type and the known length of the literal.
11406 -- The index type is not necessarily Positive, so the upper bound is
11407 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11409 else
11410 declare
11416 Prefix =>
11420 Left_Opnd =>
11423 Prefix =>
11425 Expressions =>
11427 Right_Opnd =>
11436 begin
11438 Set_String_Literal_Low_Bound
11441 else
11442 -- If the index type is an enumeration type, build bounds
11443 -- expression with attributes.
11445 Set_String_Literal_Low_Bound
11449 Prefix =>
11456 -- Build bona fide subtype for the string, and wrap it in an
11457 -- unchecked conversion, because the backend expects the
11458 -- String_Literal_Subtype to have a static lower bound.
11460 Index_Subtype :=
11467 -- In the context, the Index_Type may already have a constraint,
11468 -- so use common base type on string subtype. The base type may
11469 -- be used when generating attributes of the string, for example
11470 -- in the context of a slice assignment.
11495 ------------------------------
11496 -- Simplify_Type_Conversion --
11497 ------------------------------
11500 begin
11502 declare
11507 begin
11508 -- Special processing if the conversion is the expression of a
11509 -- Rounding or Truncation attribute reference. In this case we
11510 -- replace:
11512 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11514 -- by
11516 -- ityp (x)
11518 -- with the Float_Truncate flag set to False or True respectively,
11519 -- which is more efficient.
11522 and then
11528 Name_Truncation)
11529 then
11530 declare
11533 begin
11543 -----------------------------
11544 -- Unique_Fixed_Point_Type --
11545 -----------------------------
11554 -- Give error messages for true ambiguity. Messages are posted on node
11555 -- N, and entities T1, T2 are the possible interpretations.
11557 -----------------------
11558 -- Fixed_Point_Error --
11559 -----------------------
11562 begin
11568 -- Start of processing for Unique_Fixed_Point_Type
11570 begin
11571 -- The operations on Duration are visible, so Duration is always a
11572 -- possible interpretation.
11576 -- Look for fixed-point types in enclosing scopes
11585 then
11587 Fixed_Point_Error;
11589 else
11600 -- Look for visible fixed type declarations in the context
11611 then
11613 Fixed_Point_Error;
11615 else
11628 Error_Msg_NE
11630 else
11631 Error_Msg_NE
11638 ----------------------
11639 -- Valid_Conversion --
11640 ----------------------
11642 function Valid_Conversion
11647 is
11652 function Conversion_Check
11655 -- Little routine to post Msg if Valid is False, returns Valid value
11658 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11660 procedure Conversion_Error_NE
11664 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11666 function Valid_Tagged_Conversion
11669 -- Specifically test for validity of tagged conversions
11672 -- Check index and component conformance, and accessibility levels if
11673 -- the component types are anonymous access types (Ada 2005).
11675 ----------------------
11676 -- Conversion_Check --
11677 ----------------------
11679 function Conversion_Check
11682 is
11683 begin
11684 if not Valid
11686 -- A generic unit has already been analyzed and we have verified
11687 -- that a particular conversion is OK in that context. Since the
11688 -- instance is reanalyzed without relying on the relationships
11689 -- established during the analysis of the generic, it is possible
11690 -- to end up with inconsistent views of private types. Do not emit
11691 -- the error message in such cases. The rest of the machinery in
11692 -- Valid_Conversion still ensures the proper compatibility of
11693 -- target and operand types.
11695 and then not In_Instance
11696 then
11703 ------------------------
11704 -- Conversion_Error_N --
11705 ------------------------
11708 begin
11714 -------------------------
11715 -- Conversion_Error_NE --
11716 -------------------------
11718 procedure Conversion_Error_NE
11722 is
11723 begin
11729 ----------------------------
11730 -- Valid_Array_Conversion --
11731 ----------------------------
11734 is
11749 begin
11750 -- Error if wrong number of dimensions
11752 if
11754 then
11755 Conversion_Error_N
11759 -- Number of dimensions matches
11761 else
11762 -- Loop through indexes of the two arrays
11770 -- Error if index types are incompatible
11776 then
11777 Conversion_Error_N
11779 Operand);
11787 -- If component types have same base type, all set
11792 -- Here if base types of components are not the same. The only
11793 -- time this is allowed is if we have anonymous access types.
11795 -- The conversion of arrays of anonymous access types can lead
11796 -- to dangling pointers. AI-392 formalizes the accessibility
11797 -- checks that must be applied to such conversions to prevent
11798 -- out-of-scope references.
11800 elsif Ekind_In
11802 E_Anonymous_Access_Subprogram_Type)
11804 and then
11806 then
11809 then
11812 Conversion_Error_N
11822 -- Conversion not allowed because of accessibility levels
11824 else
11825 Conversion_Error_N
11831 else
11835 -- All other cases where component base types do not match
11837 else
11838 Conversion_Error_N
11840 Operand);
11844 -- Check that component subtypes statically match. For numeric
11845 -- types this means that both must be either constrained or
11846 -- unconstrained. For enumeration types the bounds must match.
11847 -- All of this is checked in Subtypes_Statically_Match.
11849 if not Subtypes_Statically_Match
11851 then
11852 Conversion_Error_N
11861 -----------------------------
11862 -- Valid_Tagged_Conversion --
11863 -----------------------------
11865 function Valid_Tagged_Conversion
11868 is
11869 begin
11870 -- Upward conversions are allowed (RM 4.6(22))
11874 then
11877 -- Downward conversion are allowed if the operand is class-wide
11878 -- (RM 4.6(23)).
11882 then
11887 then
11888 return
11892 -- Ada 2005 (AI-251): The conversion to/from interface types is
11893 -- always valid
11898 -- If the operand is a class-wide type obtained through a limited_
11899 -- with clause, and the context includes the non-limited view, use
11900 -- it to determine whether the conversion is legal.
11906 then
11911 then
11914 else
11915 Conversion_Error_NE
11922 -- Start of processing for Valid_Conversion
11924 begin
11928 declare
11936 begin
11937 -- Remove procedure calls, which syntactically cannot appear in
11938 -- this context, but which cannot be removed by type checking,
11939 -- because the context does not impose a type.
11941 -- The node may be labelled overloaded, but still contain only one
11942 -- interpretation because others were discarded earlier. If this
11943 -- is the case, retain the single interpretation if legal.
11951 then
11952 -- More than one candidate interpretation is available
11960 -- When compiling for a system where Address is of a visible
11961 -- integer type, spurious ambiguities can be produced when
11962 -- arithmetic operations have a literal operand and return
11963 -- System.Address or a descendant of it. These ambiguities
11964 -- are usually resolved by the context, but for conversions
11965 -- there is no context type and the removal of the spurious
11966 -- operations must be done explicitly here.
11968 if not Address_Is_Private
11970 then
11995 Conversion_Error_N
11998 -- If the interpretation involves a standard operator, use
11999 -- the location of the type, which may be user-defined.
12003 else
12007 Conversion_Error_N -- CODEFIX
12012 else
12016 Conversion_Error_N -- CODEFIX
12028 -- Deal with conversion of integer type to address if the pragma
12029 -- Allow_Integer_Address is in effect. We convert the conversion to
12030 -- an unchecked conversion in this case and we are all done.
12038 -- If we are within a child unit, check whether the type of the
12039 -- expression has an ancestor in a parent unit, in which case it
12040 -- belongs to its derivation class even if the ancestor is private.
12041 -- See RM 7.3.1 (5.2/3).
12045 -- Numeric types
12049 -- A universal fixed expression can be converted to any numeric type
12054 -- Also no need to check when in an instance or inlined body, because
12055 -- the legality has been established when the template was analyzed.
12056 -- Furthermore, numeric conversions may occur where only a private
12057 -- view of the operand type is visible at the instantiation point.
12058 -- This results in a spurious error if we check that the operand type
12059 -- is a numeric type.
12061 -- Note: in a previous version of this unit, the following tests were
12062 -- applied only for generated code (Comes_From_Source set to False),
12063 -- but in fact the test is required for source code as well, since
12064 -- this situation can arise in source code.
12069 -- Otherwise we need the conversion check
12071 else
12072 return Conversion_Check
12074 or else
12080 -- Array types
12086 then
12087 Conversion_Error_N
12091 else
12095 -- Ada 2005 (AI-251): Internally generated conversions of access to
12096 -- interface types added to force the displacement of the pointer to
12097 -- reference the corresponding dispatch table.
12102 then
12105 -- Ada 2005 (AI-251): Anonymous access types where target references an
12106 -- interface type.
12109 E_Anonymous_Access_Type)
12111 then
12112 -- Check the static accessibility rule of 4.6(17). Note that the
12113 -- check is not enforced when within an instance body, since the
12114 -- RM requires such cases to be caught at run time.
12116 -- If the operand is a rewriting of an allocator no check is needed
12117 -- because there are no accessibility issues.
12125 then
12126 -- In an instance, this is a run-time check, but one we know
12127 -- will fail, so generate an appropriate warning. The raise
12128 -- will be generated by Expand_N_Type_Conversion.
12132 Conversion_Error_N
12134 Operand);
12137 else
12138 Conversion_Error_N
12140 Operand);
12144 -- Special accessibility checks are needed in the case of access
12145 -- discriminants declared for a limited type.
12149 then
12150 -- When the operand is a selected access discriminant the check
12151 -- needs to be made against the level of the object denoted by
12152 -- the prefix of the selected name (Object_Access_Level handles
12153 -- checking the prefix of the operand for this case).
12158 then
12159 -- In an instance, this is a run-time check, but one we know
12160 -- will fail, so generate an appropriate warning. The raise
12161 -- will be generated by Expand_N_Type_Conversion.
12165 Conversion_Error_N
12170 -- Real error if not in instance body
12172 else
12173 Conversion_Error_N
12180 -- The case of a reference to an access discriminant from
12181 -- within a limited type declaration (which will appear as
12182 -- a discriminal) is always illegal because the level of the
12183 -- discriminant is considered to be deeper than any (nameable)
12184 -- access type.
12188 and then
12191 then
12192 Conversion_Error_N
12194 Operand);
12202 -- General and anonymous access types
12205 E_Anonymous_Access_Type)
12206 and then
12207 Conversion_Check
12209 and then not
12211 E_Access_Protected_Subprogram_Type),
12213 then
12216 then
12217 Conversion_Error_N
12222 -- Check the static accessibility rule of 4.6(17). Note that the
12223 -- check is not enforced when within an instance body, since the RM
12224 -- requires such cases to be caught at run time.
12229 N_Object_Declaration
12230 then
12231 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12232 -- conversions from an anonymous access type to a named general
12233 -- access type. Such conversions are not allowed in the case of
12234 -- access parameters and stand-alone objects of an anonymous
12235 -- access type. The implicit conversion case is recognized by
12236 -- testing that Comes_From_Source is False and that it's been
12237 -- rewritten. The Comes_From_Source test isn't sufficient because
12238 -- nodes in inlined calls to predefined library routines can have
12239 -- Comes_From_Source set to False. (Is there a better way to test
12240 -- for implicit conversions???)
12247 then
12250 -- Implicit conversions aren't allowed for objects of an
12251 -- anonymous access type, since such objects have nonstatic
12252 -- levels in Ada 2012.
12255 N_Object_Declaration
12256 then
12257 Conversion_Error_N
12262 -- Implicit conversions aren't allowed for anonymous access
12263 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12264 -- is done to exclude anonymous access results.
12268 N_Function_Specification,
12269 N_Procedure_Specification)
12270 then
12271 Conversion_Error_N
12276 -- This is a case where there's an enclosing object whose
12277 -- to which the "statically deeper than" relationship does
12278 -- not apply (such as an access discriminant selected from
12279 -- a dereference of an access parameter).
12283 then
12284 Conversion_Error_N
12289 -- In other cases, the level of the operand's type must be
12290 -- statically less deep than that of the target type, else
12291 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12295 then
12296 Conversion_Error_N
12305 then
12306 -- In an instance, this is a run-time check, but one we know
12307 -- will fail, so generate an appropriate warning. The raise
12308 -- will be generated by Expand_N_Type_Conversion.
12312 Conversion_Error_N
12314 Operand);
12317 -- If not in an instance body, this is a real error
12319 else
12320 -- Avoid generation of spurious error message
12323 Conversion_Error_N
12325 Operand);
12331 -- Special accessibility checks are needed in the case of access
12332 -- discriminants declared for a limited type.
12336 then
12337 -- When the operand is a selected access discriminant the check
12338 -- needs to be made against the level of the object denoted by
12339 -- the prefix of the selected name (Object_Access_Level handles
12340 -- checking the prefix of the operand for this case).
12345 then
12346 -- In an instance, this is a run-time check, but one we know
12347 -- will fail, so generate an appropriate warning. The raise
12348 -- will be generated by Expand_N_Type_Conversion.
12352 Conversion_Error_N
12357 -- If not in an instance body, this is a real error
12359 else
12360 Conversion_Error_N
12367 -- The case of a reference to an access discriminant from
12368 -- within a limited type declaration (which will appear as
12369 -- a discriminal) is always illegal because the level of the
12370 -- discriminant is considered to be deeper than any (nameable)
12371 -- access type.
12374 and then
12377 then
12378 Conversion_Error_N
12380 Operand);
12386 -- In the presence of limited_with clauses we have to use non-limited
12387 -- views, if available.
12391 -- Helper function to handle limited views
12393 --------------------------
12394 -- Full_Designated_Type --
12395 --------------------------
12400 begin
12401 -- Handle the limited view of a type
12406 then
12408 else
12413 -- Local Declarations
12421 -- Start of processing for Check_Limited
12423 begin
12427 else
12429 Conversion_Error_NE
12434 -- Ada 2005 AI-384: legality rule is symmetric in both
12435 -- designated types. The conversion is legal (with possible
12436 -- constraint check) if either designated type is
12437 -- unconstrained.
12440 or else
12442 and then
12445 then
12446 -- Special case, if Value_Size has been used to make the
12447 -- sizes different, the conversion is not allowed even
12448 -- though the subtypes statically match.
12453 then
12454 Conversion_Error_NE
12457 Conversion_Error_NE
12462 -- Normal case where conversion is allowed
12464 else
12468 else
12469 Error_Msg_NE
12477 -- Access to subprogram types. If the operand is an access parameter,
12478 -- the type has a deeper accessibility that any master, and cannot be
12479 -- assigned. We must make an exception if the conversion is part of an
12480 -- assignment and the target is the return object of an extended return
12481 -- statement, because in that case the accessibility check takes place
12482 -- after the return.
12486 -- Note: this test of Opnd_Type is there to prevent entering this
12487 -- branch in the case of a remote access to subprogram type, which
12488 -- is internally represented as an E_Record_Type.
12491 then
12495 and then
12499 then
12500 Conversion_Error_N
12502 Operand);
12503 Conversion_Error_N
12506 Operand);
12508 Error_Msg_NE
12513 -- Check that the designated types are subtype conformant
12519 -- Check the static accessibility rule of 4.6(20)
12523 then
12524 Conversion_Error_N
12526 Operand);
12528 -- Check that if the operand type is declared in a generic body,
12529 -- then the target type must be declared within that same body
12530 -- (enforces last sentence of 4.6(20)).
12533 declare
12539 begin
12546 Conversion_Error_N
12555 -- Remote access to subprogram types
12559 then
12560 -- It is valid to convert from one RAS type to another provided
12561 -- that their specification statically match.
12563 -- Note: at this point, remote access to subprogram types have been
12564 -- expanded to their E_Record_Type representation, and we need to
12565 -- go back to the original access type definition using the
12566 -- Corresponding_Remote_Type attribute in order to check that the
12567 -- designated profiles match.
12572 Check_Subtype_Conformant
12575 Old_Id =>
12577 Err_Loc =>
12578 N);
12581 -- If it was legal in the generic, it's legal in the instance
12586 -- If both are tagged types, check legality of view conversions
12589 and then
12591 then
12594 -- Types derived from the same root type are convertible
12599 -- In an instance or an inlined body, there may be inconsistent views of
12600 -- the same type, or of types derived from a common root.
12603 and then
12606 then
12609 -- Special check for common access type error case
12613 then
12615 Conversion_Error_NE -- CODEFIX
12619 -- Here we have a real conversion error
12621 else
12622 Conversion_Error_NE