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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) 1992-2012, 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 ------------------------------------------------------------------------------
83 -----------------------
84 -- Local Subprograms --
85 -----------------------
87 -- Second pass (top-down) type checking and overload resolution procedures
88 -- Typ is the type required by context. These procedures propagate the type
89 -- information recursively to the descendants of N. If the node is not
90 -- overloaded, its Etype is established in the first pass. If overloaded,
91 -- the Resolve routines set the correct type. For arith. operators, the
92 -- Etype is the base type of the context.
94 -- Note that Resolve_Attribute is separated off in Sem_Attr
96 function Bad_Unordered_Enumeration_Reference
99 -- Node N contains a potentially dubious reference to type T, either an
100 -- explicit comparison, or an explicit range. This function returns True
101 -- if the type T is an enumeration type for which No pragma Order has been
102 -- given, and the reference N is not in the same extended source unit as
103 -- the declaration of T.
106 -- Enforce the restrictions on the use of discriminants when constraining
107 -- a component of a discriminated type (record or concurrent type).
110 -- Given a node for an operator associated with type T, check that
111 -- the operator is visible. Operators all of whose operands are
112 -- universal must be checked for visibility during resolution
113 -- because their type is not determinable based on their operands.
115 procedure Check_Fully_Declared_Prefix
118 -- Check that the type of the prefix of a dereference is not incomplete
121 -- Given a call node, N, which is known to occur immediately within the
122 -- subprogram being called, determines whether it is a detectable case of
123 -- an infinite recursion, and if so, outputs appropriate messages. Returns
124 -- True if an infinite recursion is detected, and False otherwise.
127 -- If the type of the object being initialized uses the secondary stack
128 -- directly or indirectly, create a transient scope for the call to the
129 -- init proc. This is because we do not create transient scopes for the
130 -- initialization of individual components within the init proc itself.
131 -- Could be optimized away perhaps?
134 -- N is the node for a logical operator. If the operator is predefined, and
135 -- the root type of the operands is Standard.Boolean, then a check is made
136 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
137 -- the style check for Style_Check_Boolean_And_Or.
140 -- Determine whether E is an access type declared by an access declaration,
141 -- and not an (anonymous) allocator type.
144 -- Utility to check whether the entity for an operator is a predefined
145 -- operator, in which case the expression is left as an operator in the
146 -- tree (else it is rewritten into a call). An instance of an intrinsic
147 -- conversion operation may be given an operator name, but is not treated
148 -- like an operator. Note that an operator that is an imported back-end
149 -- builtin has convention Intrinsic, but is expected to be rewritten into
150 -- a call, so such an operator is not treated as predefined by this
151 -- predicate.
154 -- If a default expression in entry call N depends on the discriminants
155 -- of the task, it must be replaced with a reference to the discriminant
156 -- of the task being called.
158 procedure Resolve_Op_Concat_Arg
163 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
164 -- concatenation operator. The operand is either of the array type or of
165 -- the component type. If the operand is an aggregate, and the component
166 -- type is composite, this is ambiguous if component type has aggregates.
169 -- Does the first part of the work of Resolve_Op_Concat
172 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
173 -- has been resolved. See Resolve_Op_Concat for details.
210 function Operator_Kind
213 -- Utility to map the name of an operator into the corresponding Node. Used
214 -- by other node rewriting procedures.
217 -- Resolve actuals of call, and add default expressions for missing ones.
218 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
219 -- called subprogram.
222 -- Called from Resolve_Call, when the prefix denotes an entry or element
223 -- of entry family. Actuals are resolved as for subprograms, and the node
224 -- is rebuilt as an entry call. Also called for protected operations. Typ
225 -- is the context type, which is used when the operation is a protected
226 -- function with no arguments, and the return value is indexed.
229 -- A call to a user-defined intrinsic operator is rewritten as a call to
230 -- the corresponding predefined operator, with suitable conversions. Note
231 -- that this applies only for intrinsic operators that denote predefined
232 -- operators, not ones that are intrinsic imports of back-end builtins.
235 -- Ditto, for unary operators (arithmetic ones and "not" on signed
236 -- integer types for VMS).
239 -- If an operator node resolves to a call to a user-defined operator,
240 -- rewrite the node as a function call.
242 procedure Make_Call_Into_Operator
246 -- Inverse transformation: if an operator is given in functional notation,
247 -- then after resolving the node, transform into an operator node, so
248 -- that operands are resolved properly. Recall that predefined operators
249 -- do not have a full signature and special resolution rules apply.
251 procedure Rewrite_Renamed_Operator
255 -- An operator can rename another, e.g. in an instantiation. In that
256 -- case, the proper operator node must be constructed and resolved.
259 -- The String_Literal_Subtype is built for all strings that are not
260 -- operands of a static concatenation operation. If the argument is
261 -- not a N_String_Literal node, then the call has no effect.
264 -- Build subtype of array type, with the range specified by the slice
267 -- Called after N has been resolved and evaluated, but before range checks
268 -- have been applied. Currently simplifies a combination of floating-point
269 -- to integer conversion and Truncation attribute.
272 -- A universal_fixed expression in an universal context is unambiguous if
273 -- there is only one applicable fixed point type. Determining whether there
274 -- is only one requires a search over all visible entities, and happens
275 -- only in very pathological cases (see 6115-006).
277 -------------------------
278 -- Ambiguous_Character --
279 -------------------------
284 begin
288 -- First the ones in Standard
293 -- Include Wide_Wide_Character in Ada 2005 mode
299 -- Now any other types that match
309 -------------------------
310 -- Analyze_And_Resolve --
311 -------------------------
314 begin
320 begin
325 -- Version withs check(s) suppressed
327 procedure Analyze_And_Resolve
331 is
334 begin
336 declare
338 begin
344 else
345 declare
347 begin
355 and then Scope_Is_Transient
356 then
357 -- This can only happen if a transient scope was created for an inner
358 -- expression, which will be removed upon completion of the analysis
359 -- of an enclosing construct. The transient scope must have the
360 -- suppress status of the enclosing environment, not of this Analyze
361 -- call.
364 Scope_Suppress;
368 procedure Analyze_And_Resolve
371 is
374 begin
376 declare
378 begin
384 else
385 declare
387 begin
396 Scope_Suppress;
400 ----------------------------------------
401 -- Bad_Unordered_Enumeration_Reference --
402 ----------------------------------------
404 function Bad_Unordered_Enumeration_Reference
407 is
408 begin
411 and then Warn_On_Unordered_Enumeration_Type
416 ----------------------------
417 -- Check_Discriminant_Use --
418 ----------------------------
426 begin
427 -- Any use in a spec-expression is legal
434 -- Discriminant cannot be used to constrain a scalar type
441 then
446 -- The following check catches the unusual case where a
447 -- discriminant appears within an index constraint that is part of
448 -- a larger expression within a constraint on a component, e.g. "C
449 -- : Int range 1 .. F (new A(1 .. D))". For now we only check case
450 -- of record components, and note that a similar check should also
451 -- apply in the case of discriminant constraints below. ???
453 -- Note that the check for N_Subtype_Declaration below is to
454 -- detect the valid use of discriminants in the constraints of a
455 -- subtype declaration when this subtype declaration appears
456 -- inside the scope of a record type (which is syntactically
457 -- illegal, but which may be created as part of derived type
458 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
459 -- for more info.
463 and then not
465 and then
467 N_Subtype_Declaration)
469 then
470 Error_Msg_N
475 -- Detect a common error:
477 -- type R (D : Positive := 100) is record
478 -- Name : String (1 .. D);
479 -- end record;
481 -- The default value causes an object of type R to be allocated
482 -- with room for Positive'Last characters. The RM does not mandate
483 -- the allocation of the maximum size, but that is what GNAT does
484 -- so we should warn the programmer that there is a problem.
493 -- Return True if type T has a large enough range that any
494 -- array whose index type covered the whole range of the type
495 -- would likely raise Storage_Error.
497 ------------------------
498 -- Large_Storage_Type --
499 ------------------------
502 begin
503 -- The type is considered large if its bounds are known at
504 -- compile time and if it requires at least as many bits as
505 -- a Positive to store the possible values.
509 and then
514 -- Start of processing for Check_Large
516 begin
517 -- Check that the Disc has a large range
523 -- If the enclosing type is limited, we allocate only the
524 -- default value, not the maximum, and there is no need for
525 -- a warning.
531 -- Check that it is the high bound
535 then
539 -- Check the array allows a large range at this bound. First
540 -- find the array
554 -- Next, find the dimension
562 loop
571 -- Now, check the dimension has a large range
577 -- Warn about the danger
579 Error_Msg_N
589 -- Legal case is in index or discriminant constraint
592 N_Discriminant_Association)
593 then
595 Error_Msg_N
600 then
601 Error_Msg_N
607 -- Otherwise, context is an expression. It should not be within (i.e. a
608 -- subexpression of) a constraint for a component.
610 else
614 N_Subtype_Indication,
615 N_Entry_Declaration)
616 loop
622 -- If the discriminant is used in an expression that is a bound of a
623 -- scalar type, an Itype is created and the bounds are attached to
624 -- its range, not to the original subtype indication. Such use is of
625 -- course a double fault.
629 N_Derived_Type_Definition)
632 -- The constraint itself may be given by a subtype indication,
633 -- rather than by a more common discrete range.
636 and then
640 then
641 Error_Msg_N
647 --------------------------------
648 -- Check_For_Visible_Operator --
649 --------------------------------
652 begin
654 Error_Msg_NE -- CODEFIX
656 Error_Msg_N -- CODEFIX
661 ----------------------------------
662 -- Check_Fully_Declared_Prefix --
663 ----------------------------------
665 procedure Check_Fully_Declared_Prefix
668 is
669 begin
670 -- Check that the designated type of the prefix of a dereference is
671 -- not an incomplete type. This cannot be done unconditionally, because
672 -- dereferences of private types are legal in default expressions. This
673 -- case is taken care of in Check_Fully_Declared, called below. There
674 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
676 -- This consideration also applies to similar checks for allocators,
677 -- qualified expressions, and type conversions.
679 -- An additional exception concerns other per-object expressions that
680 -- are not directly related to component declarations, in particular
681 -- representation pragmas for tasks. These will be per-object
682 -- expressions if they depend on discriminants or some global entity.
683 -- If the task has access discriminants, the designated type may be
684 -- incomplete at the point the expression is resolved. This resolution
685 -- takes place within the body of the initialization procedure, where
686 -- the discriminant is replaced by its discriminal.
690 then
693 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
694 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
695 -- Analyze_Object_Renaming, and Freeze_Entity.
701 E_Incomplete_Type
703 then
705 else
710 ------------------------------
711 -- Check_Infinite_Recursion --
712 ------------------------------
719 -- Check whether list of actuals is identical to list of formals of
720 -- called function (which is also the enclosing scope).
722 ------------------------
723 -- Same_Argument_List --
724 ------------------------
731 begin
734 else
743 then
754 -- Start of processing for Check_Infinite_Recursion
756 begin
757 -- Special case, if this is a procedure call and is a call to the
758 -- current procedure with the same argument list, then this is for
759 -- sure an infinite recursion and we insert a call to raise SE.
763 and then Same_Argument_List
764 then
765 declare
767 begin
771 then
782 -- If not that special case, search up tree, quitting if we reach a
783 -- construct (e.g. a conditional) that tells us that this is not a
784 -- case for an infinite recursion warning.
787 loop
790 -- If no parent, then we were not inside a subprogram, this can for
791 -- example happen when processing certain pragmas in a spec. Just
792 -- return False in this case.
798 -- Done if we get to subprogram body, this is definitely an infinite
799 -- recursion case if we did not find anything to stop us.
803 -- If appearing in conditional, result is false
806 N_And_Then,
807 N_Case_Expression,
808 N_Case_Statement,
809 N_Conditional_Expression,
810 N_If_Statement)
811 then
816 then
817 -- If the call is the expression of a return statement and the
818 -- actuals are identical to the formals, it's worth a warning.
819 -- However, we skip this if there is an immediately preceding
820 -- raise statement, since the call is never executed.
822 -- Furthermore, this corresponds to a common idiom:
824 -- function F (L : Thing) return Boolean is
825 -- begin
826 -- raise Program_Error;
827 -- return F (L);
828 -- end F;
830 -- for generating a stub function
833 and then Same_Argument_List
834 then
837 -- OK, return statement is in a statement list, look for raise
839 declare
842 begin
843 -- Skip past N_Freeze_Entity nodes generated by expansion
848 loop
852 -- If no raise statement, give warning. We look at the
853 -- original node, because in the case of "raise ... with
854 -- ...", the node has been transformed into a call.
857 and then
865 else
876 -------------------------------
877 -- Check_Initialization_Call --
878 -------------------------------
884 -- Check whether the creation of an object of the type will involve
885 -- use of the secondary stack. If T is a record type, this is true
886 -- if the expression for some component uses the secondary stack, e.g.
887 -- through a call to a function that returns an unconstrained value.
888 -- False if T is controlled, because cleanups occur elsewhere.
890 -------------
891 -- Uses_SS --
892 -------------
899 begin
900 -- Normally we want to use the underlying type, but if it's not set
901 -- then continue with T.
918 then
919 -- The expression for a dynamic component may be rewritten
920 -- as a dereference, so retrieve original node.
924 -- Return True if the expression is a call to a function
925 -- (including an attribute function such as Image, or a
926 -- user-defined operator) with a result that requires a
927 -- transient scope.
934 then
947 else
952 -- Start of processing for Check_Initialization_Call
954 begin
955 -- Establish a transient scope if the type needs it
962 ---------------------------------------
963 -- Check_No_Direct_Boolean_Operators --
964 ---------------------------------------
967 begin
970 then
971 -- Restriction only applies to original source code
983 ------------------------------
984 -- Check_Parameterless_Call --
985 ------------------------------
991 -- If the prefix is of an access_to_subprogram type, the node must be
992 -- rewritten as a call. Ditto if the prefix is overloaded and all its
993 -- interpretations are access to subprograms.
995 ---------------------------
996 -- Prefix_Is_Access_Subp --
997 ---------------------------
1003 begin
1004 -- If the context is an attribute reference that can apply to
1005 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1011 then
1016 return
1019 else
1024 then
1035 -- Start of processing for Check_Parameterless_Call
1037 begin
1038 -- Defend against junk stuff if errors already detected
1045 then
1052 -- If the context expects a value, and the name is a procedure, this is
1053 -- most likely a missing 'Access. Don't try to resolve the parameterless
1054 -- call, error will be caught when the outer call is analyzed.
1059 and then
1061 N_Function_Call,
1062 N_Procedure_Call_Statement)
1063 then
1067 -- Rewrite as call if overloadable entity that is (or could be, in the
1068 -- overloaded case) a function call. If we know for sure that the entity
1069 -- is an enumeration literal, we do not rewrite it.
1071 -- If the entity is the name of an operator, it cannot be a call because
1072 -- operators cannot have default parameters. In this case, this must be
1073 -- a string whose contents coincide with an operator name. Set the kind
1074 -- of the node appropriately.
1082 -- Rewrite as call if it is an explicit dereference of an expression of
1083 -- a subprogram access type, and the subprogram type is not that of a
1084 -- procedure or entry.
1086 or else
1089 -- Rewrite as call if it is a selected component which is a function,
1090 -- this is the case of a call to a protected function (which may be
1091 -- overloaded with other protected operations).
1093 or else
1096 or else
1098 E_Procedure)
1101 -- If one of the above three conditions is met, rewrite as call. Apply
1102 -- the rewriting only once.
1104 then
1107 then
1109 -- This may be a prefixed call that was not fully analyzed, e.g.
1110 -- an actual in an instance.
1115 then
1125 -- If overloaded, overload set belongs to new copy
1129 -- Change node to parameterless function call (note that the
1130 -- Parameter_Associations associations field is left set to Empty,
1131 -- its normal default value since there are no parameters)
1149 -----------------------------
1150 -- Is_Definite_Access_Type --
1151 -----------------------------
1155 begin
1161 ----------------------
1162 -- Is_Predefined_Op --
1163 ----------------------
1166 begin
1167 -- Predefined operators are intrinsic subprograms
1173 -- A call to a back-end builtin is never a predefined operator
1184 -----------------------------
1185 -- Make_Call_Into_Operator --
1186 -----------------------------
1188 procedure Make_Call_Into_Operator
1192 is
1207 -- If the operand is not universal, and the operator is given by an
1208 -- expanded name, verify that the operand has an interpretation with a
1209 -- type defined in the given scope of the operator.
1212 -- Find a type of the given class in package Pack that contains the
1213 -- operator.
1215 ---------------------------
1216 -- Operand_Type_In_Scope --
1217 ---------------------------
1224 begin
1228 else
1242 ---------------
1243 -- Type_In_P --
1244 ---------------
1250 -- Verify that node is not part of the type declaration for the
1251 -- candidate type, which would otherwise be invisible.
1253 -------------
1254 -- In_Decl --
1255 -------------
1261 begin
1270 else
1273 loop
1276 else
1285 -- Start of processing for Type_In_P
1287 begin
1288 -- If the context type is declared in the prefix package, this is the
1289 -- desired base type.
1294 else
1298 and then not In_Decl
1299 then
1310 -- Start of processing for Make_Call_Into_Operator
1312 begin
1315 -- Binary operator
1325 -- Unary operator
1327 else
1333 -- If the operator is denoted by an expanded name, and the prefix is
1334 -- not Standard, but the operator is a predefined one whose scope is
1335 -- Standard, then this is an implicit_operator, inserted as an
1336 -- interpretation by the procedure of the same name. This procedure
1337 -- overestimates the presence of implicit operators, because it does
1338 -- not examine the type of the operands. Verify now that the operand
1339 -- type appears in the given scope. If right operand is universal,
1340 -- check the other operand. In the case of concatenation, either
1341 -- argument can be the component type, so check the type of the result.
1342 -- If both arguments are literals, look for a type of the right kind
1343 -- defined in the given scope. This elaborate nonsense is brought to
1344 -- you courtesy of b33302a. The type itself must be frozen, so we must
1345 -- find the type of the proper class in the given scope.
1347 -- A final wrinkle is the multiplication operator for fixed point types,
1348 -- which is defined in Standard only, and not in the scope of the
1349 -- fixed point type itself.
1354 -- If the entity being called is defined in the given package, it is
1355 -- a renaming of a predefined operator, and known to be legal.
1359 then
1362 -- Visibility does not need to be checked in an instance: if the
1363 -- operator was not visible in the generic it has been diagnosed
1364 -- already, else there is an implicit copy of it in the instance.
1372 then
1377 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1378 -- available.
1383 then
1386 else
1395 and then Is_Binary
1397 then
1403 -- Verify that the scope contains a type that corresponds to
1404 -- the given literal. Optimize the case where Pack is Standard.
1426 else
1435 else
1444 then
1447 -- If the type is defined elsewhere, and the operator is not
1448 -- defined in the given scope (by a renaming declaration, e.g.)
1449 -- then this is an error as well. If an extension of System is
1450 -- present, and the type may be defined there, Pack must be
1451 -- System itself.
1458 then
1461 else
1467 then
1474 Error_Msg_NE
1479 -- Detect a mismatch between the context type and the result type
1480 -- in the named package, which is otherwise not detected if the
1481 -- operands are universal. Check is only needed if source entity is
1482 -- an operator, not a function that renames an operator.
1489 and then not In_Instance
1490 then
1493 or else
1495 then
1496 -- Already checked above
1500 -- Operator may be defined in an extension of System
1504 then
1507 else
1508 -- Could we use Wrong_Type here??? (this would require setting
1509 -- Etype (N) to the actual type found where Typ was expected).
1520 else
1524 -- If this is a call to a function that renames a predefined equality,
1525 -- the renaming declaration provides a type that must be used to
1526 -- resolve the operands. This must be done now because resolution of
1527 -- the equality node will not resolve any remaining ambiguity, and it
1528 -- assumes that the first operand is not overloaded.
1533 then
1541 -- Do rewrite setting Comes_From_Source on the result if the original
1542 -- call came from source. Although it is not strictly the case that the
1543 -- operator as such comes from the source, logically it corresponds
1544 -- exactly to the function call in the source, so it should be marked
1545 -- this way (e.g. to make sure that validity checks work fine).
1547 declare
1549 begin
1554 -- If this is an arithmetic operator and the result type is private,
1555 -- the operands and the result must be wrapped in conversion to
1556 -- expose the underlying numeric type and expand the proper checks,
1557 -- e.g. on division.
1561 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1562 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1571 else
1576 -------------------
1577 -- Operator_Kind --
1578 -------------------
1580 function Operator_Kind
1583 is
1586 begin
1587 -- Use CASE statement or array???
1624 else
1628 -- Unary operators
1630 else
1639 else
1647 ----------------------------
1648 -- Preanalyze_And_Resolve --
1649 ----------------------------
1654 begin
1658 -- We suppress all checks for this analysis, since the checks will
1659 -- be applied properly, and in the right location, when the default
1660 -- expression is reanalyzed and reexpanded later on.
1664 Expander_Mode_Restore;
1668 -- Version without context type
1673 begin
1680 Expander_Mode_Restore;
1684 ----------------------------------
1685 -- Replace_Actual_Discriminants --
1686 ----------------------------------
1693 -- Comment needed???
1695 -------------------
1696 -- Process_Discr --
1697 -------------------
1702 begin
1708 then
1724 -- Start of processing for Replace_Actual_Discriminants
1726 begin
1740 else
1745 -------------
1746 -- Resolve --
1747 -------------
1763 -- Determine whether a node comes from a predefined library unit or
1764 -- Standard.
1767 -- Try and fix up a literal so that it matches its expected type. New
1768 -- literals are manufactured if necessary to avoid cascaded errors.
1771 -- Return the current scope. Skip loop scopes created for the purpose of
1772 -- quantified expression analysis since those do not appear in the tree.
1775 -- Additional diagnostics when an ambiguous call has an ambiguous
1776 -- argument (typically a controlling actual).
1779 -- Called when attempt at resolving current expression fails
1781 ------------------------------------
1782 -- Comes_From_Predefined_Lib_Unit --
1783 -------------------------------------
1786 begin
1787 return
1789 or else Is_Predefined_File_Name
1793 --------------------
1794 -- Patch_Up_Value --
1795 --------------------
1798 begin
1815 then
1820 Char_Literal_Value =>
1836 --------------------------
1837 -- Proper_Current_Scope --
1838 --------------------------
1843 begin
1846 -- Skip a loop scope created for quantified expression analysis
1850 then
1852 else
1860 -------------------------------
1861 -- Report_Ambiguous_Argument --
1862 -------------------------------
1869 begin
1873 then
1876 -- Could use comments on what is going on here???
1884 else
1893 -----------------------
1894 -- Resolution_Failed --
1895 -----------------------
1898 begin
1904 -- The caller will return without calling the expander, so we need
1905 -- to set the analyzed flag. Note that it is fine to set Analyzed
1906 -- to True even if we are in the middle of a shallow analysis,
1907 -- (see the spec of sem for more details) since this is an error
1908 -- situation anyway, and there is no point in repeating the
1909 -- analysis later (indeed it won't work to repeat it later, since
1910 -- we haven't got a clear resolution of which entity is being
1911 -- referenced.)
1917 -- Start of processing for Resolve
1919 begin
1924 -- Access attribute on remote subprogram cannot be used for a non-remote
1925 -- access-to-subprogram type.
1936 then
1937 Error_Msg_N
1943 -- If the context is a Remote_Access_To_Subprogram, access attributes
1944 -- must be resolved with the corresponding fat pointer. There is no need
1945 -- to check for the attribute name since the return type of an
1946 -- attribute is never a remote type.
1951 then
1952 declare
1960 begin
1961 -- Check that Typ is a remote access-to-subprogram type
1965 -- Prefix (N) must statically denote a remote subprogram
1966 -- declared in a package specification.
1970 Attr = Attribute_Unrestricted_Access
1971 then
1986 or else
1988 then
1990 Error_Msg_N
1992 N);
1995 -- If we are generating code in distributed mode, perform
1996 -- semantic checks against corresponding remote entities.
1998 if Full_Expander_Active
2000 then
2001 Check_Subtype_Conformant
2003 Old_Id => Designated_Type
2029 then
2034 -- Return if already analyzed
2041 -- Return if type = Any_Type (previous error encountered)
2050 -- If not overloaded, then we know the type, and all that needs doing
2051 -- is to check that this type is compatible with the context.
2057 -- In the overloaded case, we must select the interpretation that
2058 -- is compatible with the context (i.e. the type passed to Resolve)
2060 else
2061 -- Loop through possible interpretations
2071 -- We are only interested in interpretations that are compatible
2072 -- with the expected type, any other interpretations are ignored.
2077 Write_Eol;
2080 else
2081 -- Skip the current interpretation if it is disabled by an
2082 -- abstract operator. This action is performed only when the
2083 -- type against which we are resolving is the same as the
2084 -- type of the interpretation.
2091 then
2099 -- First matching interpretation
2107 -- Matching interpretation that is not the first, maybe an
2108 -- error, but there are some cases where preference rules are
2109 -- used to choose between the two possibilities. These and
2110 -- some more obscure cases are handled in Disambiguate.
2112 else
2113 -- If the current statement is part of a predefined library
2114 -- unit, then all interpretations which come from user level
2115 -- packages should not be considered.
2117 if From_Lib
2119 then
2126 -- Disambiguation has succeeded. Skip the remaining
2127 -- interpretations.
2137 else
2138 -- Before we issue an ambiguity complaint, check for
2139 -- the case of a subprogram call where at least one
2140 -- of the arguments is Any_Type, and if so, suppress
2141 -- the message, since it is a cascaded error.
2144 declare
2148 begin
2160 Write_Eol;
2173 then
2178 then
2182 -- Not that special case, so issue message using the
2183 -- flag Ambiguous to control printing of the header
2184 -- message only at the start of an ambiguous set.
2189 then
2190 Error_Msg_N
2193 else
2194 Error_Msg_NE -- CODEFIX
2202 Error_Msg_N
2204 else
2205 Error_Msg_N -- CODEFIX
2211 then
2212 Report_Ambiguous_Argument;
2218 -- By default, the error message refers to the candidate
2219 -- interpretation. But if it is a predefined operator, it
2220 -- is implicitly declared at the declaration of the type
2221 -- of the operand. Recover the sloc of that declaration
2222 -- for the error message.
2228 Standard_Standard
2229 then
2234 then
2242 Standard_Standard
2243 then
2248 then
2252 -- If this is an indirect call, use the subprogram_type
2253 -- in the message, to have a meaningful location. Also
2254 -- indicate if this is an inherited operation, created
2255 -- by a type declaration.
2260 then
2262 Error_Msg_Sloc :=
2264 else
2271 then
2272 -- Special-case the message for universal_fixed
2273 -- operators, which are not declared with the type
2274 -- of the operand, but appear forever in Standard.
2278 then
2279 Error_Msg_N
2283 else
2284 Error_Msg_N
2288 elsif
2290 then
2291 Error_Msg_N
2293 else
2294 Error_Msg_N -- CODEFIX
2301 -- We have a matching interpretation, Expr_Type is the type
2302 -- from this interpretation, and Seen is the entity.
2304 -- For an operator, just set the entity name. The type will be
2305 -- set by the specific operator resolution routine.
2320 -- AI05-0139-2: Expression is overloaded because type has
2321 -- implicit dereference. If type matches context, no implicit
2322 -- dereference is involved.
2333 then
2336 -- For an explicit dereference, attribute reference, range,
2337 -- short-circuit form (which is not an operator node), or call
2338 -- with a name that is an explicit dereference, there is
2339 -- nothing to be done at this point.
2342 N_Attribute_Reference,
2343 N_And_Then,
2344 N_Indexed_Component,
2345 N_Or_Else,
2346 N_Range,
2347 N_Selected_Component,
2348 N_Slice)
2350 then
2353 -- For procedure or function calls, set the type of the name,
2354 -- and also the entity pointer for the prefix.
2358 then
2365 then
2370 -- For all other cases, just set the type of the Name
2372 else
2380 -- Move to next interpretation
2388 -- At this stage Found indicates whether or not an acceptable
2389 -- interpretation exists. If not, then we have an error, except that if
2390 -- the context is Any_Type as a result of some other error, then we
2391 -- suppress the error report.
2396 -- If type we are looking for is Void, then this is the procedure
2397 -- call case, and the error is simply that what we gave is not a
2398 -- procedure name (we think of procedure calls as expressions with
2399 -- types internally, but the user doesn't think of them this way!)
2403 -- Special case message if function used as a procedure
2408 then
2409 Error_Msg_NE
2413 -- Otherwise give general message (not clear what cases this
2414 -- covers, but no harm in providing for them!)
2416 else
2422 -- Otherwise we do have a subexpression with the wrong type
2424 -- Check for the case of an allocator which uses an access type
2425 -- instead of the designated type. This is a common error and we
2426 -- specialize the message, posting an error on the operand of the
2427 -- allocator, complaining that we expected the designated type of
2428 -- the allocator.
2434 then
2438 -- Check for view mismatch on Null in instances, for which the
2439 -- view-swapping mechanism has no identifier.
2445 then
2450 -- Check for an aggregate. Sometimes we can get bogus aggregates
2451 -- from misuse of parentheses, and we are about to complain about
2452 -- the aggregate without even looking inside it.
2454 -- Instead, if we have an aggregate of type Any_Composite, then
2455 -- analyze and resolve the component fields, and then only issue
2456 -- another message if we get no errors doing this (otherwise
2457 -- assume that the errors in the aggregate caused the problem).
2461 then
2462 -- Disable expansion in any case. If there is a type mismatch
2463 -- it may be fatal to try to expand the aggregate. The flag
2464 -- would otherwise be set to false when the error is posted.
2468 declare
2470 -- Check one aggregate, and set Found to True if we have a
2471 -- definite error in any of its elements
2474 -- Check one element of aggregate and set Found to True if
2475 -- we definitely have an error in the element.
2477 ----------------
2478 -- Check_Aggr --
2479 ----------------
2484 begin
2497 -- If this is a default-initialized component, then
2498 -- there is nothing to check. The box will be
2499 -- replaced by the appropriate call during late
2500 -- expansion.
2511 ----------------
2512 -- Check_Elmt --
2513 ----------------
2516 begin
2517 -- If we have a nested aggregate, go inside it (to
2518 -- attempt a naked analyze-resolve of the aggregate can
2519 -- cause undesirable cascaded errors). Do not resolve
2520 -- expression if it needs a type from context, as for
2521 -- integer * fixed expression.
2526 else
2531 then
2541 begin
2546 -- If an error message was issued already, Found got reset to
2547 -- True, so if it is still False, issue standard Wrong_Type msg.
2552 then
2553 declare
2555 begin
2561 -- Protected operation: retrieve operation name
2565 else
2575 declare
2579 begin
2586 Error_Msg_NE
2592 else
2596 else
2602 Resolution_Failed;
2605 -- Test if we have more than one interpretation for the context
2608 Resolution_Failed;
2611 -- Only one intepretation
2613 else
2614 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2615 -- the "+" on T is abstract, and the operands are of universal type,
2616 -- the above code will have (incorrectly) resolved the "+" to the
2617 -- universal one in Standard. Therefore check for this case and give
2618 -- an error. We can't do this earlier, because it would cause legal
2619 -- cases to get errors (when some other type has an abstract "+").
2625 then
2630 then
2631 Error_Msg_NE
2640 -- Here we have an acceptable interpretation for the context
2642 -- Propagate type information and normalize tree for various
2643 -- predefined operations. If the context only imposes a class of
2644 -- types, rather than a specific type, propagate the actual type
2645 -- downward.
2651 Typ = Any_Discrete
2652 then
2655 -- Any_Fixed is legal in a real context only if a specific fixed-
2656 -- point type is imposed. If Norman Cohen can be confused by this,
2657 -- it deserves a separate message.
2661 then
2668 -- A user-defined operator is transformed into a function call at
2669 -- this point, so that further processing knows that operators are
2670 -- really operators (i.e. are predefined operators). User-defined
2671 -- operators that are intrinsic are just renamings of the predefined
2672 -- ones, and need not be turned into calls either, but if they rename
2673 -- a different operator, we must transform the node accordingly.
2674 -- Instantiations of Unchecked_Conversion are intrinsic but are
2675 -- treated as functions, even if given an operator designator.
2680 then
2686 and then
2688 N_Subprogram_Renaming_Declaration
2689 then
2692 -- If the node is rewritten, it will be fully resolved in
2693 -- Rewrite_Renamed_Operator.
2703 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2705 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2707 when N_Short_Circuit
2708 => Resolve_Short_Circuit (N, Ctx_Type);
2710 when N_Attribute_Reference
2711 => Resolve_Attribute (N, Ctx_Type);
2713 when N_Case_Expression
2714 => Resolve_Case_Expression (N, Ctx_Type);
2716 when N_Character_Literal
2717 => Resolve_Character_Literal (N, Ctx_Type);
2719 when N_Conditional_Expression
2720 => Resolve_Conditional_Expression (N, Ctx_Type);
2722 when N_Expanded_Name
2723 => Resolve_Entity_Name (N, Ctx_Type);
2725 when N_Explicit_Dereference
2726 => Resolve_Explicit_Dereference (N, Ctx_Type);
2728 when N_Expression_With_Actions
2729 => Resolve_Expression_With_Actions (N, Ctx_Type);
2731 when N_Extension_Aggregate
2732 => Resolve_Extension_Aggregate (N, Ctx_Type);
2734 when N_Function_Call
2735 => Resolve_Call (N, Ctx_Type);
2737 when N_Identifier
2738 => Resolve_Entity_Name (N, Ctx_Type);
2740 when N_Indexed_Component
2741 => Resolve_Indexed_Component (N, Ctx_Type);
2743 when N_Integer_Literal
2744 => Resolve_Integer_Literal (N, Ctx_Type);
2746 when N_Membership_Test
2747 => Resolve_Membership_Op (N, Ctx_Type);
2749 when N_Null => Resolve_Null (N, Ctx_Type);
2751 when N_Op_And | N_Op_Or | N_Op_Xor
2752 => Resolve_Logical_Op (N, Ctx_Type);
2754 when N_Op_Eq | N_Op_Ne
2755 => Resolve_Equality_Op (N, Ctx_Type);
2757 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2758 => Resolve_Comparison_Op (N, Ctx_Type);
2760 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2762 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2763 N_Op_Divide | N_Op_Mod | N_Op_Rem
2765 => Resolve_Arithmetic_Op (N, Ctx_Type);
2767 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2769 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2771 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2772 => Resolve_Unary_Op (N, Ctx_Type);
2774 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2776 when N_Procedure_Call_Statement
2777 => Resolve_Call (N, Ctx_Type);
2779 when N_Operator_Symbol
2780 => Resolve_Operator_Symbol (N, Ctx_Type);
2782 when N_Qualified_Expression
2783 => Resolve_Qualified_Expression (N, Ctx_Type);
2785 when N_Quantified_Expression => null;
2787 when N_Raise_xxx_Error
2788 => Set_Etype (N, Ctx_Type);
2790 when N_Range => Resolve_Range (N, Ctx_Type);
2792 when N_Real_Literal
2793 => Resolve_Real_Literal (N, Ctx_Type);
2795 when N_Reference => Resolve_Reference (N, Ctx_Type);
2797 when N_Selected_Component
2798 => Resolve_Selected_Component (N, Ctx_Type);
2800 when N_Slice => Resolve_Slice (N, Ctx_Type);
2802 when N_String_Literal
2803 => Resolve_String_Literal (N, Ctx_Type);
2805 when N_Subprogram_Info
2806 => Resolve_Subprogram_Info (N, Ctx_Type);
2808 when N_Type_Conversion
2809 => Resolve_Type_Conversion (N, Ctx_Type);
2811 when N_Unchecked_Expression =>
2812 Resolve_Unchecked_Expression (N, Ctx_Type);
2814 when N_Unchecked_Type_Conversion =>
2815 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2816 end case;
2818 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2819 -- expression of an anonymous access type that occurs in the context
2820 -- of a named general access type, except when the expression is that
2821 -- of a membership test. This ensures proper legality checking in
2822 -- terms of allowed conversions (expressions that would be illegal to
2823 -- convert implicitly are allowed in membership tests).
2825 if Ada_Version >= Ada_2012
2826 and then Ekind (Ctx_Type) = E_General_Access_Type
2827 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2828 and then Nkind (Parent (N)) not in N_Membership_Test
2829 then
2830 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2831 Analyze_And_Resolve (N, Ctx_Type);
2832 end if;
2834 -- If the subexpression was replaced by a non-subexpression, then
2835 -- all we do is to expand it. The only legitimate case we know of
2836 -- is converting procedure call statement to entry call statements,
2837 -- but there may be others, so we are making this test general.
2839 if Nkind (N) not in N_Subexpr then
2840 Debug_A_Exit ("resolving ", N, " (done)");
2841 Expand (N);
2842 return;
2843 end if;
2845 -- AI05-144-2: Check dangerous order dependence within an expression
2846 -- that is not a subexpression. Exclude RHS of an assignment, because
2847 -- both sides may have side-effects and the check must be performed
2848 -- over the statement.
2850 if Nkind (Parent (N)) not in N_Subexpr
2851 and then Nkind (Parent (N)) /= N_Assignment_Statement
2852 and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
2853 then
2854 Check_Order_Dependence;
2855 end if;
2857 -- The expression is definitely NOT overloaded at this point, so
2858 -- we reset the Is_Overloaded flag to avoid any confusion when
2859 -- reanalyzing the node.
2861 Set_Is_Overloaded (N, False);
2863 -- Freeze expression type, entity if it is a name, and designated
2864 -- type if it is an allocator (RM 13.14(10,11,13)).
2866 -- Now that the resolution of the type of the node is complete, and
2867 -- we did not detect an error, we can expand this node. We skip the
2868 -- expand call if we are in a default expression, see section
2869 -- "Handling of Default Expressions" in Sem spec.
2871 Debug_A_Exit ("resolving ", N, " (done)");
2873 -- We unconditionally freeze the expression, even if we are in
2874 -- default expression mode (the Freeze_Expression routine tests this
2875 -- flag and only freezes static types if it is set).
2877 -- Ada 2012 (AI05-177): Expression functions do not freeze. Only
2878 -- their use (in an expanded call) freezes.
2880 if Ekind (Proper_Current_Scope) /= E_Function
2881 or else Nkind (Original_Node (Unit_Declaration_Node
2882 (Proper_Current_Scope))) /= N_Expression_Function
2883 then
2884 Freeze_Expression (N);
2885 end if;
2887 -- Now we can do the expansion
2889 Expand (N);
2890 end if;
2891 end Resolve;
2893 -------------
2894 -- Resolve --
2895 -------------
2897 -- Version with check(s) suppressed
2899 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2900 begin
2901 if Suppress = All_Checks then
2902 declare
2903 Svg : constant Suppress_Record := Scope_Suppress;
2904 begin
2905 Scope_Suppress := Suppress_All;
2906 Resolve (N, Typ);
2907 Scope_Suppress := Svg;
2908 end;
2910 else
2911 declare
2912 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
2913 begin
2914 Scope_Suppress.Suppress (Suppress) := True;
2915 Resolve (N, Typ);
2916 Scope_Suppress.Suppress (Suppress) := Svg;
2917 end;
2918 end if;
2919 end Resolve;
2921 -------------
2922 -- Resolve --
2923 -------------
2925 -- Version with implicit type
2927 procedure Resolve (N : Node_Id) is
2928 begin
2929 Resolve (N, Etype (N));
2930 end Resolve;
2932 ---------------------
2933 -- Resolve_Actuals --
2934 ---------------------
2936 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2937 Loc : constant Source_Ptr := Sloc (N);
2938 A : Node_Id;
2939 F : Entity_Id;
2940 A_Typ : Entity_Id;
2941 F_Typ : Entity_Id;
2942 Prev : Node_Id := Empty;
2943 Orig_A : Node_Id;
2945 procedure Check_Argument_Order;
2946 -- Performs a check for the case where the actuals are all simple
2947 -- identifiers that correspond to the formal names, but in the wrong
2948 -- order, which is considered suspicious and cause for a warning.
2950 procedure Check_Prefixed_Call;
2951 -- If the original node is an overloaded call in prefix notation,
2953 -- Try_Object_Operation has already verified that there is a valid
2954 -- interpretation, but the form of the actual can only be determined
2955 -- once the primitive operation is identified.
2958 -- If the actual is missing in a call, insert in the actuals list
2959 -- an instance of the default expression. The insertion is always
2960 -- a named association.
2963 -- Check whether T1 and T2, or their full views, are derived from a
2964 -- common type. Used to enforce the restrictions on array conversions
2965 -- of AI95-00246.
2968 -- Predicate to determine whether an actual that is a concatenation
2969 -- will be evaluated statically and does not need a transient scope.
2970 -- This must be determined before the actual is resolved and expanded
2971 -- because if needed the transient scope must be introduced earlier.
2973 --------------------------
2974 -- Check_Argument_Order --
2975 --------------------------
2978 begin
2979 -- Nothing to do if no parameters, or original node is neither a
2980 -- function call nor a procedure call statement (happens in the
2981 -- operator-transformed-to-function call case), or the call does
2982 -- not come from source, or this warning is off.
2984 if not Warn_On_Parameter_Order
2988 then
2992 declare
2995 begin
2996 -- Nothing to do if only one parameter
3002 -- Here if at least two arguments
3004 declare
3010 -- Set True if an out of order case is found
3012 begin
3013 -- Collect identifier names of actuals, fail if any actual is
3014 -- not a simple identifier, and record max length of name.
3020 else
3026 -- If we got this far, all actuals are identifiers and the list
3027 -- of their names is stored in the Actuals array.
3032 -- If we ran out of formals, that's odd, probably an error
3033 -- which will be detected elsewhere, but abandon the search.
3039 -- If name matches and is in order OK
3044 else
3045 -- If no match, see if it is elsewhere in list and if so
3046 -- flag potential wrong order if type is compatible.
3050 and then
3052 then
3058 -- No match
3066 -- If Formals left over, also probably an error, skip warning
3072 -- Here we give the warning if something was out of order
3075 Error_Msg_N
3082 -------------------------
3083 -- Check_Prefixed_Call --
3084 -------------------------
3093 begin
3094 -- Check whether the call is a prefixed call, with or without
3095 -- additional actuals.
3098 or else
3104 then
3107 then
3108 -- Introduce dereference on object in prefix
3110 New_A :=
3118 then
3119 -- Introduce an implicit 'Access in prefix
3122 Error_Msg_NE
3138 --------------------
3139 -- Insert_Default --
3140 --------------------
3146 begin
3147 -- Missing argument in call, nothing to insert
3152 else
3153 -- Note that we do a full New_Copy_Tree, so that any associated
3154 -- Itypes are properly copied. This may not be needed any more,
3155 -- but it does no harm as a safety measure! Defaults of a generic
3156 -- formal may be out of bounds of the corresponding actual (see
3157 -- cc1311b) and an additional check may be required.
3159 Actval :=
3160 New_Copy_Tree
3167 then
3173 then
3176 then
3177 -- If default is a real literal, do not introduce a
3178 -- conversion whose effect may depend on the run-time
3179 -- size of universal real.
3183 else
3194 -- Resolve aggregates with their base type, to avoid scope
3195 -- anomalies: the subtype was first built in the subprogram
3196 -- declaration, and the current call may be nested.
3200 else
3204 else
3207 -- See note above concerning aggregates
3211 then
3214 -- Resolve entities with their own type, which may differ from
3215 -- the type of a reference in a generic context (the view
3216 -- swapping mechanism did not anticipate the re-analysis of
3217 -- default values in calls).
3222 else
3227 -- If default is a tag indeterminate function call, propagate tag
3228 -- to obtain proper dispatching.
3232 then
3238 -- If the default expression raises constraint error, then just
3239 -- silently replace it with an N_Raise_Constraint_Error node, since
3240 -- we already gave the warning on the subprogram spec. If node is
3241 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3242 -- the warnings removal machinery.
3246 then
3254 Assoc :=
3259 -- Case of insertion is first named actual
3263 then
3270 else
3274 else
3278 -- Case of insertion is not first named actual
3280 else
3281 Set_Next_Named_Actual
3293 -------------------
3294 -- Same_Ancestor --
3295 -------------------
3301 begin
3304 then
3310 then
3317 --------------------------
3318 -- Static_Concatenation --
3319 --------------------------
3322 begin
3329 -- Concatenation is static when both operands are static and
3330 -- the concatenation operator is a predefined one.
3333 and then
3335 and then
3340 declare
3342 begin
3345 and then
3349 else
3355 -- Start of processing for Resolve_Actuals
3357 begin
3358 Check_Argument_Order;
3361 Check_Prefixed_Call;
3370 -- If we have an error in any actual or formal, indicated by a type
3371 -- of Any_Type, then abandon resolution attempt, and set result type
3372 -- to Any_Type.
3376 then
3381 -- Case where actual is present
3383 -- If the actual is an entity, generate a reference to it now. We
3384 -- do this before the actual is resolved, because a formal of some
3385 -- protected subprogram, or a task discriminant, will be rewritten
3386 -- during expansion, and the source entity reference may be lost.
3391 then
3397 then
3409 then
3410 -- If style checking mode on, check match of formal name
3418 -- If the formal is Out or In_Out, do not resolve and expand the
3419 -- conversion, because it is subsequently expanded into explicit
3420 -- temporaries and assignments. However, the object of the
3421 -- conversion can be resolved. An exception is the case of tagged
3422 -- type conversion with a class-wide actual. In that case we want
3423 -- the tag check to occur and no temporary will be needed (no
3424 -- representation change can occur) and the parameter is passed by
3425 -- reference, so we go ahead and resolve the type conversion.
3426 -- Another exception is the case of reference to component or
3427 -- subcomponent of a bit-packed array, in which case we want to
3428 -- defer expansion to the point the in and out assignments are
3429 -- performed.
3434 then
3437 then
3438 -- In a view conversion, the conversion must be legal in
3439 -- both directions, and thus both component types must be
3440 -- aliased, or neither (4.6 (8)).
3442 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3443 -- the privacy requirement should not apply to generic
3444 -- types, and should be checked in an instance. ARG query
3445 -- is in order ???
3449 then
3450 Error_Msg_N
3454 -- Comment here??? what set of cases???
3456 elsif
3458 then
3459 -- Check view conv between unrelated by ref array types
3463 then
3464 Error_Msg_N
3468 -- In Ada 2005 mode, check view conversion component
3469 -- type cannot be private, tagged, or volatile. Note
3470 -- that we only apply this to source conversions. The
3471 -- generated code can contain conversions which are
3472 -- not subject to this test, and we cannot extract the
3473 -- component type in such cases since it is not present.
3477 then
3478 declare
3480 Component_Type
3482 begin
3487 then
3488 Error_Msg_N
3499 -- Resolve expression if conversion is all OK
3504 then
3508 -- If the actual is a function call that returns a limited
3509 -- unconstrained object that needs finalization, create a
3510 -- transient scope for it, so that it can receive the proper
3511 -- finalization list.
3516 and then Full_Expander_Active
3518 then
3522 -- A small optimization: if one of the actuals is a concatenation
3523 -- create a block around a procedure call to recover stack space.
3524 -- This alleviates stack usage when several procedure calls in
3525 -- the same statement list use concatenation. We do not perform
3526 -- this wrapping for code statements, where the argument is a
3527 -- static string, and we want to preserve warnings involving
3528 -- sequences of such statements.
3532 and then Full_Expander_Active
3533 and then
3537 then
3541 else
3545 and then
3548 then
3549 Error_Msg_N
3562 -- (Ada 2005: AI-251): If the actual is an allocator whose
3563 -- directly designated type is a class-wide interface, we build
3564 -- an anonymous access type to use it as the type of the
3565 -- allocator. Later, when the subprogram call is expanded, if
3566 -- the interface has a secondary dispatch table the expander
3567 -- will add a type conversion to force the correct displacement
3568 -- of the pointer.
3571 declare
3577 begin
3580 then
3588 -- Ada 2005, AI-162:If the actual is an allocator, the
3589 -- innermost enclosing statement is the master of the
3590 -- created object. This needs to be done with expansion
3591 -- enabled only, otherwise the transient scope will not
3592 -- be removed in the expansion of the wrapped construct.
3595 and then Full_Expander_Active
3596 then
3602 -- (Ada 2005): The call may be to a primitive operation of
3603 -- a tagged synchronized type, declared outside of the type.
3604 -- In this case the controlling actual must be converted to
3605 -- its corresponding record type, which is the formal type.
3606 -- The actual may be a subtype, either because of a constraint
3607 -- or because it is a generic actual, so use base type to
3608 -- locate concurrent type.
3615 then
3616 -- If the actual is overloaded, look for an interpretation
3617 -- that has a synchronized type.
3622 else
3623 declare
3627 begin
3632 then
3642 declare
3645 begin
3648 else
3652 -- Tagged synchronized type (case 1): the actual is a
3653 -- concurrent type.
3657 then
3659 Unchecked_Convert_To
3663 -- Tagged synchronized type (case 2): the formal is a
3664 -- concurrent type.
3667 and then Present
3672 then
3675 -- Common case
3677 else
3681 else
3683 -- not a synchronized operation.
3694 N_Procedure_Call_Statement)
3695 then
3696 -- In formal mode, check that actual parameters matching
3697 -- formals of tagged types are objects (or ancestor type
3698 -- conversions of objects), not general expressions.
3705 declare
3710 begin
3712 Check_SPARK_Restriction
3715 -- In formal mode, the only view conversions are those
3716 -- involving ancestor conversion of an extended type.
3718 elsif not
3724 then
3725 if Ekind_In
3727 then
3728 Check_SPARK_Restriction
3731 else
3732 Check_SPARK_Restriction
3736 else
3741 else
3745 -- In formal mode, the only view conversions are those
3746 -- involving ancestor conversion of an extended type.
3750 then
3751 Check_SPARK_Restriction
3757 -- Save actual for subsequent check on order dependence, and
3758 -- indicate whether actual is modifiable. For AI05-0144-2.
3760 -- If this is a call to a reference function that is the result
3761 -- of expansion, as in element iterator loops, this does not lead
3762 -- to a dangerous order dependence: only subsequent use of the
3763 -- denoted element might, in some enclosing call.
3767 then
3771 -- For mode IN, if actual is an entity, and the type of the formal
3772 -- has warnings suppressed, then we reset Never_Set_In_Source for
3773 -- the calling entity. The reason for this is to catch cases like
3774 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3775 -- uses trickery to modify an IN parameter.
3782 then
3786 -- Perform error checks for IN and IN OUT parameters
3790 -- Check unset reference. For scalar parameters, it is clearly
3791 -- wrong to pass an uninitialized value as either an IN or
3792 -- IN-OUT parameter. For composites, it is also clearly an
3793 -- error to pass a completely uninitialized value as an IN
3794 -- parameter, but the case of IN OUT is trickier. We prefer
3795 -- not to give a warning here. For example, suppose there is
3796 -- a routine that sets some component of a record to False.
3797 -- It is perfectly reasonable to make this IN-OUT and allow
3798 -- either initialized or uninitialized records to be passed
3799 -- in this case.
3801 -- For partially initialized composite values, we also avoid
3802 -- warnings, since it is quite likely that we are passing a
3803 -- partially initialized value and only the initialized fields
3804 -- will in fact be read in the subprogram.
3809 then
3813 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3814 -- actual to a nested call, since this is case of reading an
3815 -- out parameter, which is not allowed.
3820 then
3825 -- Case of OUT or IN OUT parameter
3829 -- For an Out parameter, check for useless assignment. Note
3830 -- that we can't set Last_Assignment this early, because we may
3831 -- kill current values in Resolve_Call, and that call would
3832 -- clobber the Last_Assignment field.
3834 -- Note: call Warn_On_Useless_Assignment before doing the check
3835 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3836 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3837 -- reflects the last assignment, not this one!
3844 then
3849 -- Validate the form of the actual. Note that the call to
3850 -- Is_OK_Variable_For_Out_Formal generates the required
3851 -- reference in this case.
3853 -- A call to an initialization procedure for an aggregate
3854 -- component may initialize a nested component of a constant
3855 -- designated object. In this context the object is variable.
3859 then
3863 -- What's the following about???
3867 else
3868 Kill_All_Checks;
3877 -- Apply appropriate range checks for in, out, and in-out
3878 -- parameters. Out and in-out parameters also need a separate
3879 -- check, if there is a type conversion, to make sure the return
3880 -- value meets the constraints of the variable before the
3881 -- conversion.
3883 -- Gigi looks at the check flag and uses the appropriate types.
3884 -- For now since one flag is used there is an optimization which
3885 -- might not be done in the In Out case since Gigi does not do
3886 -- any analysis. More thought required about this ???
3890 -- Apply predicate checks, unless this is a call to the
3891 -- predicate check function itself, which would cause an
3892 -- infinite recursion.
3896 then
3900 -- Apply required constraint checks
3913 then
3919 then
3925 then
3928 else
3932 -- Ada 2005 (AI-231): Note that the controlling parameter case
3933 -- already existed in Ada 95, which is partially checked
3934 -- elsewhere (see Checks), and we don't want the warning
3935 -- message to differ.
3940 then
3942 Apply_Compile_Time_Constraint_Error
3948 Apply_Compile_Time_Constraint_Error
3960 Apply_Scalar_Range_Check
3962 else
3963 Apply_Range_Check
3967 else
3972 then
3974 else
3980 -- An actual associated with an access parameter is implicitly
3981 -- converted to the anonymous access type of the formal and must
3982 -- satisfy the legality checks for access conversions.
3986 Error_Msg_N
3990 -- If the actual is an access selected component of a variable,
3991 -- the call may modify its designated object. It is reasonable
3992 -- to treat this as a potential modification of the enclosing
3993 -- record, to prevent spurious warnings that it should be
3994 -- declared as a constant, because intuitively programmers
3995 -- regard the designated subcomponent as part of the record.
4000 then
4005 -- Check bad case of atomic/volatile argument (RM C.6(12))
4009 then
4012 then
4013 Error_Msg_NE
4019 then
4020 Error_Msg_NE
4026 -- Check that subprograms don't have improper controlling
4027 -- arguments (RM 3.9.2 (9)).
4029 -- A primitive operation may have an access parameter of an
4030 -- incomplete tagged type, but a dispatching call is illegal
4031 -- if the type is still incomplete.
4037 declare
4039 begin
4043 then
4044 Error_Msg_NE
4058 then
4063 then
4065 Error_Msg_NE
4069 -- Apply the checks described in 3.10.2(27): if the context is a
4070 -- specific access-to-object, the actual cannot be class-wide.
4071 -- Use base type to exclude access_to_subprogram cases.
4078 and then
4083 -- Disable these checks for call to imported C++ subprograms
4085 and then not
4089 then
4090 Error_Msg_N
4095 Error_Msg_NE
4102 -- If it is a named association, treat the selector_name as a
4103 -- proper identifier, and mark the corresponding entity. Ignore
4104 -- this reference in Alfa mode, as it refers to an entity not in
4105 -- scope at the point of reference, so the reference should be
4106 -- ignored for computing effects of subprograms.
4109 and then not Alfa_Mode
4110 then
4125 -- Case where actual is not present
4127 else
4128 Insert_Default;
4135 -----------------------
4136 -- Resolve_Allocator --
4137 -----------------------
4149 procedure Check_Allocator_Discrim_Accessibility
4152 -- Check that accessibility level associated with an access discriminant
4153 -- initialized in an allocator by the expression Disc_Exp is not deeper
4154 -- than the level of the allocator type Alloc_Typ. An error message is
4155 -- issued if this condition is violated. Specialized checks are done for
4156 -- the cases of a constraint expression which is an access attribute or
4157 -- an access discriminant.
4160 -- If the allocator is an actual in a call, it is allowed to be class-
4161 -- wide when the context is not because it is a controlling actual.
4163 -------------------------------------------
4164 -- Check_Allocator_Discrim_Accessibility --
4165 -------------------------------------------
4167 procedure Check_Allocator_Discrim_Accessibility
4170 is
4171 begin
4174 then
4175 Error_Msg_N
4178 -- When the expression is an Access attribute the level of the prefix
4179 -- object must not be deeper than that of the allocator's type.
4183 Attribute_Access
4186 then
4187 Error_Msg_N
4189 Disc_Exp);
4191 -- When the expression is an access discriminant the check is against
4192 -- the level of the prefix object.
4198 then
4199 Error_Msg_N
4201 Disc_Exp);
4203 -- All other cases are legal
4205 else
4210 ----------------------------
4211 -- In_Dispatching_Context --
4212 ----------------------------
4217 begin
4223 -- Start of processing for Resolve_Allocator
4225 begin
4226 -- Replace general access with specific type
4236 -- For qualified expression, resolve the expression using the
4237 -- given subtype (nothing to do for type mark, subtype indication)
4242 and then not In_Dispatching_Context
4243 then
4244 Error_Msg_N
4251 -- A qualified expression requires an exact match of the type,
4252 -- class-wide matching is not allowed.
4257 then
4261 -- Calls to build-in-place functions are not currently supported in
4262 -- allocators for access types associated with a simple storage pool.
4263 -- Supporting such allocators may require passing additional implicit
4264 -- parameters to build-in-place functions (or a significant revision
4265 -- of the current b-i-p implementation to unify the handling for
4266 -- multiple kinds of storage pools). ???
4270 then
4271 declare
4274 begin
4276 and then
4277 Present (Get_Rep_Pragma
4279 then
4280 Error_Msg_N
4287 -- A special accessibility check is needed for allocators that
4288 -- constrain access discriminants. The level of the type of the
4289 -- expression used to constrain an access discriminant cannot be
4290 -- deeper than the type of the allocator (in contrast to access
4291 -- parameters, where the level of the actual can be arbitrary).
4293 -- We can't use Valid_Conversion to perform this check because
4294 -- in general the type of the allocator is unrelated to the type
4295 -- of the access discriminant.
4299 then
4306 then
4309 -- Get the first component expression of the aggregate
4319 else
4323 else
4342 else
4347 else
4356 -- For a subtype mark or subtype indication, freeze the subtype
4358 else
4362 Error_Msg_N
4366 -- A special accessibility check is needed for allocators that
4367 -- constrain access discriminants. The level of the type of the
4368 -- expression used to constrain an access discriminant cannot be
4369 -- deeper than the type of the allocator (in contrast to access
4370 -- parameters, where the level of the actual can be arbitrary).
4371 -- We can't use Valid_Conversion to perform this check because
4372 -- in general the type of the allocator is unrelated to the type
4373 -- of the access discriminant.
4378 then
4388 else
4402 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4403 -- check that the level of the type of the created object is not deeper
4404 -- than the level of the allocator's access type, since extensions can
4405 -- now occur at deeper levels than their ancestor types. This is a
4406 -- static accessibility level check; a run-time check is also needed in
4407 -- the case of an initialized allocator with a class-wide argument (see
4408 -- Expand_Allocator_Expression).
4412 then
4413 declare
4416 begin
4421 else
4427 then
4432 E);
4438 -- Do not apply Ada 2005 accessibility checks on a class-wide
4439 -- allocator if the type given in the allocator is a formal
4440 -- type. A run-time check will be performed in the instance.
4450 -- Check for allocation from an empty storage pool
4455 -- If the context is an unchecked conversion, as may happen within an
4456 -- inlined subprogram, the allocator is being resolved with its own
4457 -- anonymous type. In that case, if the target type has a specific
4458 -- storage pool, it must be inherited explicitly by the allocator type.
4462 then
4463 Set_Associated_Storage_Pool
4471 -- Check that an allocator with task parts isn't for a nested access
4472 -- type when restriction No_Task_Hierarchy applies.
4476 then
4480 -- An erroneous allocator may be rewritten as a raise Program_Error
4481 -- statement.
4485 -- An anonymous access discriminant is the definition of a
4486 -- coextension.
4490 N_Discriminant_Specification
4491 then
4492 declare
4496 begin
4497 -- Ada 2012 AI05-0052: If the designated type of the allocator
4498 -- is limited, then the allocator shall not be used to define
4499 -- the value of an access discriminant unless the discriminated
4500 -- type is immutably limited.
4505 then
4506 Error_Msg_N
4512 -- Avoid marking an allocator as a dynamic coextension if it is
4513 -- within a static construct.
4519 -- Cleanup for potential static coextensions
4521 else
4527 -- Report a simple error: if the designated object is a local task,
4528 -- its body has not been seen yet, and its activation will fail an
4529 -- elaboration check.
4536 then
4541 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4542 -- type with a task component on a subpool. This action must raise
4543 -- Program_Error at runtime.
4549 then
4560 ---------------------------
4561 -- Resolve_Arithmetic_Op --
4562 ---------------------------
4564 -- Used for resolving all arithmetic operators except exponentiation
4575 -- We do the resolution using the base type, because intermediate values
4576 -- in expressions always are of the base type, not a subtype of it.
4579 -- Returns True if N is in a context that expects "any real type"
4582 -- Return True iff given type is Integer or universal real/integer
4585 -- Choose type of integer literal in fixed-point operation to conform
4586 -- to available fixed-point type. T is the type of the other operand,
4587 -- which is needed to determine the expected type of N.
4590 -- Set operand type to T if universal
4592 -------------------------------
4593 -- Expected_Type_Is_Any_Real --
4594 -------------------------------
4597 begin
4598 -- N is the expression after "delta" in a fixed_point_definition;
4599 -- see RM-3.5.9(6):
4602 N_Decimal_Fixed_Point_Definition,
4604 -- N is one of the bounds in a real_range_specification;
4605 -- see RM-3.5.7(5):
4607 N_Real_Range_Specification,
4609 -- N is the expression of a delta_constraint;
4610 -- see RM-J.3(3):
4612 N_Delta_Constraint);
4615 -----------------------------
4616 -- Is_Integer_Or_Universal --
4617 -----------------------------
4624 begin
4630 else
4636 then
4647 ----------------------------
4648 -- Set_Mixed_Mode_Operand --
4649 ----------------------------
4655 begin
4658 -- A universal integer literal is resolved as standard integer
4659 -- except in the case of a fixed-point result, where we leave it
4660 -- as universal (to be handled by Exp_Fixd later on)
4664 else
4672 then
4673 -- A universal real can appear in a fixed-type context. We resolve
4674 -- the literal with that context, even though this might raise an
4675 -- exception prematurely (the other operand may be zero).
4682 then
4683 -- Integer arg in mixed-mode operation. Resolve with universal
4684 -- type, in case preference rule must be applied.
4690 then
4691 -- Not a mixed-mode operation, resolve with context
4697 -- N may itself be a mixed-mode operation, so use context type
4704 then
4705 -- Must be (fixed * fixed) operation, operand must have one
4706 -- compatible interpretation.
4714 then
4715 -- C * F(X) in a fixed context, where C is a real literal or a
4716 -- fixed-point expression. F must have either a fixed type
4717 -- interpretation or an integer interpretation, but not both.
4724 else
4731 else
4739 -- Reanalyze the literal with the fixed type of the context. If
4740 -- context is Universal_Fixed, we are within a conversion, leave
4741 -- the literal as a universal real because there is no usable
4742 -- fixed type, and the target of the conversion plays no role in
4743 -- the resolution.
4745 declare
4749 begin
4752 else
4758 then
4760 else
4768 else
4773 ----------------------
4774 -- Set_Operand_Type --
4775 ----------------------
4778 begin
4781 then
4786 -- Start of processing for Resolve_Arithmetic_Op
4788 begin
4793 then
4797 -- Special-case for mixed-mode universal expressions or fixed point type
4798 -- operation: each argument is resolved separately. The same treatment
4799 -- is required if one of the operands of a fixed point operation is
4800 -- universal real, since in this case we don't do a conversion to a
4801 -- specific fixed-point type (instead the expander handles the case).
4803 -- Set the type of the node to its universal interpretation because
4804 -- legality checks on an exponentiation operand need the context.
4809 then
4820 or else
4823 then
4828 -- If context is a fixed type and one operand is integer, the other
4829 -- is resolved with the type of the context.
4834 then
4841 then
4845 else
4850 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4851 -- multiplying operators from being used when the expected type is
4852 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4853 -- some cases where the expected type is actually Any_Real;
4854 -- Expected_Type_Is_Any_Real takes care of that case.
4858 then
4862 N_Unchecked_Type_Conversion)
4863 then
4870 else
4873 and then not
4875 N_Unchecked_Type_Conversion)
4876 then
4877 Error_Msg_N
4882 -- The expected type is "any real type" in contexts like
4884 -- type T is delta <universal_fixed-expression> ...
4886 -- in which case we need to set the type to Universal_Real
4887 -- so that static expression evaluation will work properly.
4891 else
4901 then
4906 -- If no previous errors, this is only possible if one operand is
4907 -- overloaded and the context is universal. Resolve as such.
4912 else
4914 and then
4916 then
4920 -- If the context is Universal_Fixed and the operands are also
4921 -- universal fixed, this is an error, unless there is only one
4922 -- applicable fixed_point type (usually Duration).
4930 else
4935 else
4940 -- If one of the arguments was resolved to a non-universal type.
4941 -- label the result of the operation itself with the same type.
4942 -- Do the same for the universal argument, if any.
4954 -- In SPARK, a multiplication or division with operands of fixed point
4955 -- types shall be qualified or explicitly converted to identify the
4956 -- result type.
4961 and then
4963 then
4964 Check_SPARK_Restriction
4968 -- Set overflow and division checking bit. Much cleverer code needed
4969 -- here eventually and perhaps the Resolve routines should be separated
4970 -- for the various arithmetic operations, since they will need
4971 -- different processing. ???
4978 -- Give warning if explicit division by zero
4982 then
4988 or else
4991 then
4992 -- Specialize the warning message according to the operation.
4993 -- The following warnings are for the case
4998 -- For division, we have two cases, for float division
4999 -- of an unconstrained float type, on a machine where
5000 -- Machine_Overflows is false, we don't get an exception
5001 -- at run-time, but rather an infinity or Nan. The Nan
5002 -- case is pretty obscure, so just warn about infinities.
5006 and then not Machine_Overflows_On_Target
5007 then
5008 Error_Msg_N
5012 -- For all other cases, we get a Constraint_Error
5014 else
5015 Apply_Compile_Time_Constraint_Error
5021 Apply_Compile_Time_Constraint_Error
5026 Apply_Compile_Time_Constraint_Error
5030 -- Division by zero can only happen with division, rem,
5031 -- and mod operations.
5037 -- Otherwise just set the flag to check at run time
5039 else
5044 -- If Restriction No_Implicit_Conditionals is active, then it is
5045 -- violated if either operand can be negative for mod, or for rem
5046 -- if both operands can be negative.
5050 then
5051 declare
5058 -- Set if corresponding operand might be negative
5060 begin
5061 Determine_Range
5065 Determine_Range
5069 -- Check if we will be generating conditionals. There are two
5070 -- cases where that can happen, first for REM, the only case
5071 -- is largest negative integer mod -1, where the division can
5072 -- overflow, but we still have to give the right result. The
5073 -- front end generates a test for this annoying case. Here we
5074 -- just test if both operands can be negative (that's what the
5075 -- expander does, so we match its logic here).
5077 -- The second case is mod where either operand can be negative.
5078 -- In this case, the back end has to generate additional tests.
5081 or else
5083 then
5094 ------------------
5095 -- Resolve_Call --
5096 ------------------
5108 function Same_Or_Aliased_Subprograms
5111 -- Returns True if the subprogram entity S is the same as E or else
5112 -- S is an alias of E.
5114 ---------------------------------
5115 -- Same_Or_Aliased_Subprograms --
5116 ---------------------------------
5118 function Same_Or_Aliased_Subprograms
5121 is
5123 begin
5128 -- Start of processing for Resolve_Call
5130 begin
5131 -- The context imposes a unique interpretation with type Typ on a
5132 -- procedure or function call. Find the entity of the subprogram that
5133 -- yields the expected type, and propagate the corresponding formal
5134 -- constraints on the actuals. The caller has established that an
5135 -- interpretation exists, and emitted an error if not unique.
5137 -- First deal with the case of a call to an access-to-subprogram,
5138 -- dereference made explicit in Analyze_Call.
5144 else
5145 -- Find the interpretation whose type (a subprogram type) has a
5146 -- return type that is compatible with the context. Analysis of
5147 -- the node has established that one exists.
5166 -- If the prefix is not an entity, then resolve it
5172 -- For an indirect call, we always invalidate checks, since we do not
5173 -- know whether the subprogram is local or global. Yes we could do
5174 -- better here, e.g. by knowing that there are no local subprograms,
5175 -- but it does not seem worth the effort. Similarly, we kill all
5176 -- knowledge of current constant values.
5178 Kill_Current_Values;
5180 -- If this is a procedure call which is really an entry call, do
5181 -- the conversion of the procedure call to an entry call. Protected
5182 -- operations use the same circuitry because the name in the call
5183 -- can be an arbitrary expression with special resolution rules.
5188 then
5192 -- Kill checks and constant values, as above for indirect case
5193 -- Who knows what happens when another task is activated?
5195 Kill_Current_Values;
5198 -- Normal subprogram call with name established in Resolve
5204 -- Otherwise we must have the case of an overloaded call
5206 else
5209 -- Initialize Nam to prevent warning (we know it will be assigned
5210 -- in the loop below, but the compiler does not know that).
5230 then
5231 -- The prefix is a parameterless function call that returns an access
5232 -- to subprogram. If parameters are present in the current call, add
5233 -- add an explicit dereference. We use the base type here because
5234 -- within an instance these may be subtypes.
5236 -- The dereference is added either in Analyze_Call or here. Should
5237 -- be consolidated ???
5246 -- Check that a call to Current_Task does not occur in an entry body
5249 declare
5252 begin
5254 loop
5257 -- Exclude calls that occur within the default of a formal
5258 -- parameter of the entry, since those are evaluated outside
5259 -- of the body.
5266 then
5268 Error_Msg_NE
5271 Error_Msg_NE
5283 -- Check that a procedure call does not occur in the context of the
5284 -- entry call statement of a conditional or timed entry call. Note that
5285 -- the case of a call to a subprogram renaming of an entry will also be
5286 -- rejected. The test for N not being an N_Entry_Call_Statement is
5287 -- defensive, covering the possibility that the processing of entry
5288 -- calls might reach this point due to later modifications of the code
5289 -- above.
5294 then
5298 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5299 -- for a procedure_or_entry_call, the procedure_name or
5300 -- procedure_prefix of the procedure_call_statement shall denote
5301 -- an entry renamed by a procedure, or (a view of) a primitive
5302 -- subprogram of a limited interface whose first parameter is
5303 -- a controlling parameter.
5308 then
5309 Error_Msg_N
5314 -- Check that this is not a call to a protected procedure or entry from
5315 -- within a protected function.
5321 then
5327 -- Freeze the subprogram name if not in a spec-expression. Note that we
5328 -- freeze procedure calls as well as function calls. Procedure calls are
5329 -- not frozen according to the rules (RM 13.14(14)) because it is
5330 -- impossible to have a procedure call to a non-frozen procedure in pure
5331 -- Ada, but in the code that we generate in the expander, this rule
5332 -- needs extending because we can generate procedure calls that need
5333 -- freezing.
5335 -- In Ada 2012, expression functions may be called within pre/post
5336 -- conditions of subsequent functions or expression functions. Such
5337 -- calls do not freeze when they appear within generated bodies, which
5338 -- would place the freeze node in the wrong scope. An expression
5339 -- function is frozen in the usual fashion, by the appearance of a real
5340 -- body, or at the end of a declarative part.
5343 and then
5346 then
5350 -- For a predefined operator, the type of the result is the type imposed
5351 -- by context, except for a predefined operation on universal fixed.
5352 -- Otherwise The type of the call is the type returned by the subprogram
5353 -- being called.
5360 -- If the subprogram returns an array type, and the context requires the
5361 -- component type of that array type, the node is really an indexing of
5362 -- the parameterless call. Resolve as such. A pathological case occurs
5363 -- when the type of the component is an access to the array type. In
5364 -- this case the call is truly ambiguous.
5367 and then
5372 and then
5373 Covers
5376 then
5377 declare
5382 begin
5385 then
5386 Error_Msg_N
5388 else
5394 or else
5396 and then
5398 then
5401 -- Indexed call to a parameterless function
5403 Index_Node :=
5405 Prefix =>
5409 else
5410 -- An Ada 2005 prefixed call to a primitive operation
5411 -- whose first parameter is the prefix. This prefix was
5412 -- prepended to the parameter list, which is actually a
5413 -- list of indexes. Remove the prefix in order to build
5414 -- the proper indexed component.
5416 Index_Node :=
5418 Prefix =>
5421 Parameter_Associations =>
5422 New_List
5427 -- Preserve the parenthesis count of the node
5431 -- Since we are correcting a node classification error made
5432 -- by the parser, we call Replace rather than Rewrite.
5446 else
5450 -- In the case where the call is to an overloaded subprogram, Analyze
5451 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5452 -- such a case Normalize_Actuals needs to be called once more to order
5453 -- the actuals correctly. Otherwise the call will have the ordering
5454 -- given by the last overloaded subprogram whether this is the correct
5455 -- one being called or not.
5462 -- In any case, call is fully resolved now. Reset Overload flag, to
5463 -- prevent subsequent overload resolution if node is analyzed again
5468 -- If we are calling the current subprogram from immediately within its
5469 -- body, then that is the case where we can sometimes detect cases of
5470 -- infinite recursion statically. Do not try this in case restriction
5471 -- No_Recursion is in effect anyway, and do it only for source calls.
5476 -- Issue warning for possible infinite recursion in the absence
5477 -- of the No_Recursion restriction.
5482 then
5483 -- Here we detected and flagged an infinite recursion, so we do
5484 -- not need to test the case below for further warnings. Also we
5485 -- are all done if we now have a raise SE node.
5491 -- If call is to immediately containing subprogram, then check for
5492 -- the case of a possible run-time detectable infinite recursion.
5494 else
5498 -- Although in general case, recursion is not statically
5499 -- checkable, the case of calling an immediately containing
5500 -- subprogram is easy to catch.
5504 -- If the recursive call is to a parameterless subprogram,
5505 -- then even if we can't statically detect infinite
5506 -- recursion, this is pretty suspicious, and we output a
5507 -- warning. Furthermore, we will try later to detect some
5508 -- cases here at run time by expanding checking code (see
5509 -- Detect_Infinite_Recursion in package Exp_Ch6).
5511 -- If the recursive call is within a handler, do not emit a
5512 -- warning, because this is a common idiom: loop until input
5513 -- is correct, catch illegal input in handler and restart.
5519 then
5520 -- For the case of a procedure call. We give the message
5521 -- only if the call is the first statement in a sequence
5522 -- of statements, or if all previous statements are
5523 -- simple assignments. This is simply a heuristic to
5524 -- decrease false positives, without losing too many good
5525 -- warnings. The idea is that these previous statements
5526 -- may affect global variables the procedure depends on.
5527 -- We also exclude raise statements, that may arise from
5528 -- constraint checks and are probably unrelated to the
5529 -- intended control flow.
5533 then
5534 declare
5536 begin
5540 N_Assignment_Statement,
5541 N_Raise_Constraint_Error)
5542 then
5551 -- Do not give warning if we are in a conditional context
5553 declare
5555 begin
5561 then
5566 -- Here warning is to be issued
5569 Error_Msg_N
5571 Error_Msg_N
5583 -- Check obsolescent reference to Ada.Characters.Handling subprogram
5587 -- If subprogram name is a predefined operator, it was given in
5588 -- functional notation. Replace call node with operator node, so
5589 -- that actuals can be resolved appropriately.
5597 then
5603 -- Create a transient scope if the resulting type requires it
5605 -- There are several notable exceptions:
5607 -- a) In init procs, the transient scope overhead is not needed, and is
5608 -- even incorrect when the call is a nested initialization call for a
5609 -- component whose expansion may generate adjust calls. However, if the
5610 -- call is some other procedure call within an initialization procedure
5611 -- (for example a call to Create_Task in the init_proc of the task
5612 -- run-time record) a transient scope must be created around this call.
5614 -- b) Enumeration literal pseudo-calls need no transient scope
5616 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
5617 -- functions) do not use the secondary stack even though the return
5618 -- type may be unconstrained.
5620 -- d) Calls to a build-in-place function, since such functions may
5621 -- allocate their result directly in a target object, and cases where
5622 -- the result does get allocated in the secondary stack are checked for
5623 -- within the specialized Exp_Ch6 procedures for expanding those
5624 -- build-in-place calls.
5626 -- e) If the subprogram is marked Inline_Always, then even if it returns
5627 -- an unconstrained type the call does not require use of the secondary
5628 -- stack. However, inlining will only take place if the body to inline
5629 -- is already present. It may not be available if e.g. the subprogram is
5630 -- declared in a child instance.
5632 -- If this is an initialization call for a type whose construction
5633 -- uses the secondary stack, and it is not a nested call to initialize
5634 -- a component, we do need to create a transient scope for it. We
5635 -- check for this by traversing the type in Check_Initialization_Call.
5641 and then not Debug_Flag_Dot_K
5642 then
5649 and then Debug_Flag_Dot_K
5650 then
5656 then
5659 elsif Full_Expander_Active
5662 and then
5664 or else
5666 then
5669 -- If the call appears within the bounds of a loop, it will
5670 -- be rewritten and reanalyzed, nothing left to do here.
5677 and then not Within_Init_Proc
5678 then
5682 -- A protected function cannot be called within the definition of the
5683 -- enclosing protected type.
5688 then
5689 Error_Msg_NE
5693 -- Propagate interpretation to actuals, and add default expressions
5694 -- where needed.
5699 -- Overloaded literals are rewritten as function calls, for purpose of
5700 -- resolution. After resolution, we can replace the call with the
5701 -- literal itself.
5707 -- Avoid validation, since it is a static function call
5713 -- If the subprogram is not global, then kill all saved values and
5714 -- checks. This is a bit conservative, since in many cases we could do
5715 -- better, but it is not worth the effort. Similarly, we kill constant
5716 -- values. However we do not need to do this for internal entities
5717 -- (unless they are inherited user-defined subprograms), since they
5718 -- are not in the business of molesting local values.
5720 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5721 -- kill all checks and values for calls to global subprograms. This
5722 -- takes care of the case where an access to a local subprogram is
5723 -- taken, and could be passed directly or indirectly and then called
5724 -- from almost any context.
5726 -- Note: we do not do this step till after resolving the actuals. That
5727 -- way we still take advantage of the current value information while
5728 -- scanning the actuals.
5730 -- We suppress killing values if we are processing the nodes associated
5731 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5732 -- type kills all the values as part of analyzing the code that
5733 -- initializes the dispatch tables.
5737 or else Suppress_Value_Tracking_On_Call
5742 then
5743 Kill_Current_Values;
5746 -- If we are warning about unread OUT parameters, this is the place to
5747 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5748 -- after the above call to Kill_Current_Values (since that call clears
5749 -- the Last_Assignment field of all local variables).
5754 then
5755 declare
5759 begin
5769 then
5779 -- If the subprogram is a primitive operation, check whether or not
5780 -- it is a correct dispatching call.
5784 then
5789 and then not In_Instance
5790 then
5794 -- If this is a dispatching call, generate the appropriate reference,
5795 -- for better source navigation in GPS.
5799 then
5802 -- Normal case, not a dispatching call: generate a call reference
5804 else
5812 -- Check for violation of restriction No_Specific_Termination_Handlers
5813 -- and warn on a potentially blocking call to Abort_Task.
5817 or else
5819 then
5826 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
5827 -- timing event violates restriction No_Relative_Delay (AI-0211). We
5828 -- need to check the second argument to determine whether it is an
5829 -- absolute or relative timing event.
5834 then
5838 -- Issue an error for a call to an eliminated subprogram. This routine
5839 -- will not perform the check if the call appears within a default
5840 -- expression.
5844 -- In formal mode, the primitive operations of a tagged type or type
5845 -- extension do not include functions that return the tagged type.
5847 -- Commented out as the call to Is_Inherited_Operation_For_Type may
5848 -- cause an error because the type entity of the parent node of
5849 -- Entity (Name (N) may not be set. ???
5850 -- So why not just add a guard ???
5852 -- if Nkind (N) = N_Function_Call
5853 -- and then Is_Tagged_Type (Etype (N))
5854 -- and then Is_Entity_Name (Name (N))
5855 -- and then Is_Inherited_Operation_For_Type
5856 -- (Entity (Name (N)), Etype (N))
5857 -- then
5858 -- Check_SPARK_Restriction ("function not inherited", N);
5859 -- end if;
5861 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
5862 -- class-wide and the call dispatches on result in a context that does
5863 -- not provide a tag, the call raises Program_Error.
5866 and then In_Instance
5871 then
5872 -- Verify that none of the formals are controlling
5874 declare
5878 begin
5901 -- All done, evaluate call and deal with elaboration issues
5908 -----------------------------
5909 -- Resolve_Case_Expression --
5910 -----------------------------
5915 begin
5926 -------------------------------
5927 -- Resolve_Character_Literal --
5928 -------------------------------
5934 begin
5935 -- Verify that the character does belong to the type of the context
5940 -- Wide_Wide_Character literals must always be defined, since the set
5941 -- of wide wide character literals is complete, i.e. if a character
5942 -- literal is accepted by the parser, then it is OK for wide wide
5943 -- character (out of range character literals are rejected).
5948 -- Always accept character literal for type Any_Character, which
5949 -- occurs in error situations and in comparisons of literals, both
5950 -- of which should accept all literals.
5955 -- For Standard.Character or a type derived from it, check that the
5956 -- literal is in range.
5963 -- For Standard.Wide_Character or a type derived from it, check that the
5964 -- literal is in range.
5971 -- For Standard.Wide_Wide_Character or a type derived from it, we
5972 -- know the literal is in range, since the parser checked!
5977 -- If the entity is already set, this has already been resolved in a
5978 -- generic context, or comes from expansion. Nothing else to do.
5983 -- Otherwise we have a user defined character type, and we can use the
5984 -- standard visibility mechanisms to locate the referenced entity.
5986 else
5999 -- If we fall through, then the literal does not match any of the
6000 -- entries of the enumeration type. This isn't just a constraint error
6001 -- situation, it is an illegality (see RM 4.2).
6003 Error_Msg_NE
6007 ---------------------------
6008 -- Resolve_Comparison_Op --
6009 ---------------------------
6011 -- Context requires a boolean type, and plays no role in resolution.
6012 -- Processing identical to that for equality operators. The result type is
6013 -- the base type, which matters when pathological subtypes of booleans with
6014 -- limited ranges are used.
6021 begin
6022 -- If this is an intrinsic operation which is not predefined, use the
6023 -- types of its declared arguments to resolve the possibly overloaded
6024 -- operands. Otherwise the operands are unambiguous and specify the
6025 -- expected type.
6030 else
6041 -- Skip remaining processing if already set to Any_Type
6047 -- Deal with other error cases
6051 T = Any_Character
6052 then
6055 else
6063 -- Resolve the operands if types OK
6072 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6073 -- types or array types except String.
6076 Check_SPARK_Restriction
6081 then
6082 Check_SPARK_Restriction
6086 -- Check comparison on unordered enumeration
6090 then
6094 -- Evaluate the relation (note we do this after the above check since
6095 -- this Eval call may change N to True/False.
6101 ------------------------------------
6102 -- Resolve_Conditional_Expression --
6103 ------------------------------------
6112 begin
6117 -- When the "then" and "else" expressions are of a scalar type, insert
6118 -- a conversion to ensure the generation of a constraint check.
6122 then
6127 -- If ELSE expression present, just resolve using the determined type
6135 then
6140 -- If no ELSE expression is present, root type must be Standard.Boolean
6141 -- and we provide a Standard.True result converted to the appropriate
6142 -- Boolean type (in case it is a derived boolean type).
6145 Else_Expr :=
6150 else
6159 -----------------------------------------
6160 -- Resolve_Discrete_Subtype_Indication --
6161 -----------------------------------------
6163 procedure Resolve_Discrete_Subtype_Indication
6166 is
6170 begin
6178 else
6188 Error_Msg_NE
6191 -- Rewrite the constraint as a range of Typ
6192 -- to allow compilation to proceed further.
6204 else
6208 -- Additionally, we must check that the bounds are compatible
6209 -- with the given subtype, which might be different from the
6210 -- type of the context.
6214 -- ??? If the above check statically detects a Constraint_Error
6215 -- it replaces the offending bound(s) of the range R with a
6216 -- Constraint_Error node. When the itype which uses these bounds
6217 -- is frozen the resulting call to Duplicate_Subexpr generates
6218 -- a new temporary for the bounds.
6220 -- Unfortunately there are other itypes that are also made depend
6221 -- on these bounds, so when Duplicate_Subexpr is called they get
6222 -- a forward reference to the newly created temporaries and Gigi
6223 -- aborts on such forward references. This is probably sign of a
6224 -- more fundamental problem somewhere else in either the order of
6225 -- itype freezing or the way certain itypes are constructed.
6227 -- To get around this problem we call Remove_Side_Effects right
6228 -- away if either bounds of R are a Constraint_Error.
6230 declare
6234 begin
6250 -------------------------
6251 -- Resolve_Entity_Name --
6252 -------------------------
6254 -- Used to resolve identifiers and expanded names
6259 begin
6260 -- If garbage from errors, set to Any_Type and return
6267 -- Replace named numbers by corresponding literals. Note that this is
6268 -- the one case where Resolve_Entity_Name must reset the Etype, since
6269 -- it is currently marked as universal.
6279 -- For enumeration literals, we need to make sure that a proper style
6280 -- check is done, since such literals are overloaded, and thus we did
6281 -- not do a style check during the first phase of analysis.
6287 -- Case of subtype name appearing as an operand in expression
6291 -- Allow use of subtype if it is a concurrent type where we are
6292 -- currently inside the body. This will eventually be expanded into a
6293 -- call to Self (for tasks) or _object (for protected objects). Any
6294 -- other use of a subtype is invalid.
6298 then
6301 -- Any other use is an error
6303 else
6304 Error_Msg_N
6308 -- Check discriminant use if entity is discriminant in current scope,
6309 -- i.e. discriminant of record or concurrent type currently being
6310 -- analyzed. Uses in corresponding body are unrestricted.
6315 then
6318 -- A parameterless generic function cannot appear in a context that
6319 -- requires resolution.
6330 then
6333 -- In all other cases, just do the possible static evaluation
6335 else
6336 -- A deferred constant that appears in an expression must have a
6337 -- completion, unless it has been removed by in-place expansion of
6338 -- an aggregate.
6344 and then not In_Spec_Expression
6346 then
6350 then
6352 else
6353 Error_Msg_N (
6362 -------------------
6363 -- Resolve_Entry --
6364 -------------------
6376 -- If the bounds of the entry family being called depend on task
6377 -- discriminants, build a new index subtype where a discriminant is
6378 -- replaced with the value of the discriminant of the target task.
6379 -- The target task is the prefix of the entry name in the call.
6381 -----------------------
6382 -- Actual_Index_Type --
6383 -----------------------
6393 -- If the bound is given by a discriminant, replace with a reference
6394 -- to the discriminant of the same name in the target task. If the
6395 -- entry name is the target of a requeue statement and the entry is
6396 -- in the current protected object, the bound to be used is the
6397 -- discriminal of the object (see Apply_Range_Checks for details of
6398 -- the transformation).
6400 -----------------------------
6401 -- Actual_Discriminant_Ref --
6402 -----------------------------
6408 begin
6413 then
6419 then
6420 -- Note: here Bound denotes a discriminant of the corresponding
6421 -- record type tskV, whose discriminal is a formal of the
6422 -- init-proc tskVIP. What we want is the body discriminal,
6423 -- which is associated to the discriminant of the original
6424 -- concurrent type tsk.
6426 return New_Occurrence_Of
6429 else
6430 Ref :=
6440 -- Start of processing for Actual_Index_Type
6442 begin
6445 then
6448 else
6462 -- Start of processing of Resolve_Entry
6464 begin
6465 -- Find name of entry being called, and resolve prefix of name with its
6466 -- own type. The prefix can be overloaded, and the name and signature of
6467 -- the entry must be taken into account.
6471 -- Case of dealing with entry family within the current tasks
6475 else
6481 -- Entry call to an entry (or entry family) in the current task. This
6482 -- is legal even though the task will deadlock. Rewrite as call to
6483 -- current task.
6485 -- This can also be a call to an entry in an enclosing task. If this
6486 -- is a single task, we have to retrieve its name, because the scope
6487 -- of the entry is the task type, not the object. If the enclosing
6488 -- task is a task type, the identity of the task is given by its own
6489 -- self variable.
6491 -- Finally this can be a requeue on an entry of the same task or
6492 -- protected object.
6499 then
6500 -- S is an enclosing task or protected object. The concurrent
6501 -- declaration has been converted into a type declaration, and
6502 -- the object itself has an object declaration that follows
6503 -- the type in the same declarative part.
6515 -- Call to current task. Will be transformed into call to Self
6522 New_N :=
6525 Selector_Name =>
6532 then
6533 -- Use the entry name (which must be unique at this point) to find
6534 -- the prefix that returns the corresponding task/protected type.
6536 declare
6542 begin
6564 -- Up to this point the expression could have been the actual in a
6565 -- simple entry call, and be given by a named association.
6569 else
6575 ------------------------
6576 -- Resolve_Entry_Call --
6577 ------------------------
6589 begin
6590 -- We kill all checks here, because it does not seem worth the effort to
6591 -- do anything better, an entry call is a big operation.
6593 Kill_All_Checks;
6595 -- Processing of the name is similar for entry calls and protected
6596 -- operation calls. Once the entity is determined, we can complete
6597 -- the resolution of the actuals.
6599 -- The selector may be overloaded, in the case of a protected object
6600 -- with overloaded functions. The type of the context is used for
6601 -- resolution.
6606 then
6607 declare
6611 begin
6630 -- Simple entry call
6638 -- Call to member of entry family
6645 -- We cannot in general check the maximum depth of protected entry calls
6646 -- at compile time. But we can tell that any protected entry call at all
6647 -- violates a specified nesting depth of zero.
6653 -- Use context type to disambiguate a protected function that can be
6654 -- called without actuals and that returns an array type, and where the
6655 -- argument list may be an indexing of the returned value.
6660 and then
6666 and then
6667 Covers
6670 then
6671 declare
6674 begin
6675 Index_Node :=
6677 Prefix =>
6681 -- Since we are correcting a node classification error made by the
6682 -- parser, we call Replace rather than Rewrite.
6695 then
6696 -- Rewrite as call to the precondition wrapper, adding the task
6697 -- object to the list of actuals. If the call is to a member of an
6698 -- entry family, include the index as well.
6700 declare
6704 begin
6713 New_Call :=
6715 Name =>
6724 -- The operation name may have been overloaded. Order the actuals
6725 -- according to the formals of the resolved entity, and set the return
6726 -- type to that of the operation.
6736 -- Create a call reference to the entry
6744 -- Verify that a procedure call cannot masquerade as an entry
6745 -- call where an entry call is expected.
6750 then
6755 then
6760 then
6765 -- After resolution, entry calls and protected procedure calls are
6766 -- changed into entry calls, for expansion. The structure of the node
6767 -- does not change, so it can safely be done in place. Protected
6768 -- function calls must keep their structure because they are
6769 -- subexpressions.
6773 -- A protected operation that is not a function may modify the
6774 -- corresponding object, and cannot apply to a constant. If this
6775 -- is an internal call, the prefix is the type itself.
6781 then
6782 Error_Msg_N
6784 Entry_Name);
6798 -- Protected functions can return on the secondary stack, in which
6799 -- case we must trigger the transient scope mechanism.
6801 elsif Full_Expander_Active
6803 then
6808 -------------------------
6809 -- Resolve_Equality_Op --
6810 -------------------------
6812 -- Both arguments must have the same type, and the boolean context does
6813 -- not participate in the resolution. The first pass verifies that the
6814 -- interpretation is not ambiguous, and the type of the left argument is
6815 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
6816 -- are strings or aggregates, allocators, or Null, they are ambiguous even
6817 -- though they carry a single (universal) type. Diagnose this case here.
6825 -- The resolution rule for conditional expressions requires that each
6826 -- such must have a unique type. This means that if several dependent
6827 -- expressions are of a non-null anonymous access type, and the context
6828 -- does not impose an expected type (as can be the case in an equality
6829 -- operation) the expression must be rejected.
6832 -- In the case of allocators, make a last-ditch attempt to find a single
6833 -- access type with the right designated type. This is semantically
6834 -- dubious, and of no interest to any real code, but c48008a makes it
6835 -- all worthwhile.
6837 ----------------------------------
6838 -- Check_Conditional_Expression --
6839 ----------------------------------
6845 begin
6852 then
6853 Error_Msg_N
6859 -----------------------------
6860 -- Find_Unique_Access_Type --
6861 -----------------------------
6868 begin
6873 else
6885 then
6898 -- Start of processing for Resolve_Equality_Op
6900 begin
6911 T = Any_Character
6912 then
6915 else
6924 then
6933 -- Conditional expressions must have a single type, and if the
6934 -- context does not impose one the dependent expressions cannot
6935 -- be anonymous access types.
6939 E_Anonymous_Access_Subprogram_Type)
6941 E_Anonymous_Access_Subprogram_Type)
6942 then
6950 -- In SPARK, equality operators = and /= for array types other than
6951 -- String are only defined when, for each index position, the
6952 -- operands have equal static bounds.
6955 -- Protect call to Matching_Static_Array_Bounds to avoid costly
6956 -- operation if not needed.
6964 then
6965 Check_SPARK_Restriction
6970 -- If the unique type is a class-wide type then it will be expanded
6971 -- into a dispatching call to the predefined primitive. Therefore we
6972 -- check here for potential violation of such restriction.
6978 if Warn_On_Redundant_Constructs
6983 then
6984 Error_Msg_N -- CODEFIX
6993 -- If this is an inequality, it may be the implicit inequality
6994 -- created for a user-defined operation, in which case the corres-
6995 -- ponding equality operation is not intrinsic, and the operation
6996 -- cannot be constant-folded. Else fold.
7001 or else Is_Intrinsic_Subprogram
7003 then
7009 then
7013 -- Ada 2005: If one operand is an anonymous access type, convert the
7014 -- other operand to it, to ensure that the underlying types match in
7015 -- the back-end. Same for access_to_subprogram, and the conversion
7016 -- verifies that the types are subtype conformant.
7018 -- We apply the same conversion in the case one of the operands is a
7019 -- private subtype of the type of the other.
7021 -- Why the Expander_Active test here ???
7023 if Full_Expander_Active
7024 and then
7026 E_Anonymous_Access_Subprogram_Type)
7028 then
7048 ----------------------------------
7049 -- Resolve_Explicit_Dereference --
7050 ----------------------------------
7058 -- The candidate prefix type, if overloaded
7063 begin
7069 -- Use the context type to select the prefix that has the correct
7070 -- designated type. Keep the first match, which will be the inner-
7071 -- most.
7078 then
7083 -- Remove access types that do not match, but preserve access
7084 -- to subprogram interpretations, in case a further dereference
7085 -- is needed (see below).
7098 else
7099 -- If no interpretation covers the designated type of the prefix,
7100 -- this is the pathological case where not all implementations of
7101 -- the prefix allow the interpretation of the node as a call. Now
7102 -- that the expected type is known, Remove other interpretations
7103 -- from prefix, rewrite it as a call, and resolve again, so that
7104 -- the proper call node is generated.
7115 New_N :=
7117 Name =>
7128 -- If not overloaded, resolve P with its own type
7130 else
7138 -- If the designated type is a packed unconstrained array type, and the
7139 -- explicit dereference is not in the context of an attribute reference,
7140 -- then we must compute and set the actual subtype, since it is needed
7141 -- by Gigi. The reason we exclude the attribute case is that this is
7142 -- handled fine by Gigi, and in fact we use such attributes to build the
7143 -- actual subtype. We also exclude generated code (which builds actual
7144 -- subtypes directly if they are needed).
7151 then
7155 -- Note: No Eval processing is required for an explicit dereference,
7156 -- because such a name can never be static.
7160 -------------------------------------
7161 -- Resolve_Expression_With_Actions --
7162 -------------------------------------
7165 begin
7169 -------------------------------
7170 -- Resolve_Indexed_Component --
7171 -------------------------------
7179 begin
7182 -- Use the context type to select the prefix that yields the correct
7183 -- component type.
7185 declare
7192 begin
7199 and then
7200 Covers
7203 then
7212 else
7218 else
7229 else
7236 -- If prefix is access type, dereference to get real array type.
7237 -- Note: we do not apply an access check because the expander always
7238 -- introduces an explicit dereference, and the check will happen there.
7244 -- If name was overloaded, set component type correctly now
7245 -- If a misplaced call to an entry family (which has no index types)
7246 -- return. Error will be diagnosed from calling context.
7250 else
7257 -- The prefix may have resolved to a string literal, in which case its
7258 -- etype has a special representation. This is only possible currently
7259 -- if the prefix is a static concatenation, written in functional
7260 -- notation.
7265 else
7272 else
7283 -- Do not generate the warning on suspicious index if we are analyzing
7284 -- package Ada.Tags; otherwise we will report the warning with the
7285 -- Prims_Ptr field of the dispatch table.
7288 or else not
7290 Ada_Tags)
7291 then
7296 -- If the array type is atomic, and is packed, and we are in a left side
7297 -- context, then this is worth a warning, since we have a situation
7298 -- where the access to the component may cause extra read/writes of
7299 -- the atomic array object, which could be considered unexpected.
7307 then
7315 -----------------------------
7316 -- Resolve_Integer_Literal --
7317 -----------------------------
7320 begin
7325 --------------------------------
7326 -- Resolve_Intrinsic_Operator --
7327 --------------------------------
7337 -- If the operand is a literal, it cannot be the expression in a
7338 -- conversion. Use a qualified expression instead.
7343 begin
7345 Res :=
7351 else
7358 -- Start of processing for Resolve_Intrinsic_Operator
7360 begin
7361 -- We must preserve the original entity in a generic setting, so that
7362 -- the legality of the operation can be verified in an instance.
7377 -- If the result or operand types are private, rewrite with unchecked
7378 -- conversions on the operands and the result, to expose the proper
7379 -- underlying numeric type.
7384 then
7386 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
7387 -- What on earth is this commented out fragment of code???
7391 else
7412 then
7413 -- Add explicit conversion where needed, and save interpretations in
7414 -- case operands are overloaded. If the context is a VMS operation,
7415 -- assert that the conversion is legal (the operands have the proper
7416 -- types to select the VMS intrinsic). Note that in rare cases the
7417 -- VMS operators may be visible, but the default System is being used
7418 -- and Address is a private type.
7429 else
7439 else
7449 else
7454 --------------------------------------
7455 -- Resolve_Intrinsic_Unary_Operator --
7456 --------------------------------------
7458 procedure Resolve_Intrinsic_Unary_Operator
7461 is
7466 begin
7485 else
7490 ------------------------
7491 -- Resolve_Logical_Op --
7492 ------------------------
7497 begin
7500 -- Predefined operations on scalar types yield the base type. On the
7501 -- other hand, logical operations on arrays yield the type of the
7502 -- arguments (and the context).
7506 else
7510 -- OK if this is a VMS-specific intrinsic operation
7515 -- The following test is required because the operands of the operation
7516 -- may be literals, in which case the resulting type appears to be
7517 -- compatible with a signed integer type, when in fact it is compatible
7518 -- only with modular types. If the context itself is universal, the
7519 -- operation is illegal.
7527 Error_Msg_N
7535 then
7539 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
7540 -- is active and the result type is standard Boolean (do not mess with
7541 -- ops that return a nonstandard Boolean type, because something strange
7542 -- is going on).
7544 -- Note: you might expect this replacement to be done during expansion,
7545 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
7546 -- is used, no part of the right operand of an "and" or "or" operator
7547 -- should be executed if the left operand would short-circuit the
7548 -- evaluation of the corresponding "and then" or "or else". If we left
7549 -- the replacement to expansion time, then run-time checks associated
7550 -- with such operands would be evaluated unconditionally, due to being
7551 -- before the condition prior to the rewriting as short-circuit forms
7552 -- during expansion.
7554 if Short_Circuit_And_Or
7557 then
7565 -- Case of OR changed to OR ELSE
7567 else
7575 -- Return now, since analysis of the rewritten ops will take care of
7576 -- other reference bookkeeping and expression folding.
7591 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
7592 -- only when both operands have same static lower and higher bounds. Of
7593 -- course the types have to match, so only check if operands are
7594 -- compatible and the node itself has no errors.
7598 then
7599 declare
7603 begin
7604 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7605 -- operation if not needed.
7612 then
7613 Check_SPARK_Restriction
7620 ---------------------------
7621 -- Resolve_Membership_Op --
7622 ---------------------------
7624 -- The context can only be a boolean type, and does not determine the
7625 -- arguments. Arguments should be unambiguous, but the preference rule for
7626 -- universal types applies.
7636 -- Analysis has determined a unique type for the left operand. Use it to
7637 -- resolve the disjuncts.
7639 ----------------------------
7640 -- Resolve_Set_Membership --
7641 ----------------------------
7646 begin
7652 -- Alternative is an expression, a range
7653 -- or a subtype mark.
7657 then
7665 -- Start of processing for Resolve_Membership_Op
7667 begin
7673 Resolve_Set_Membership;
7677 and then
7679 or else
7682 then
7685 -- Ada 2005 (AI-251): Support the following case:
7687 -- type I is interface;
7688 -- type T is tagged ...
7690 -- function Test (O : I'Class) is
7691 -- begin
7692 -- return O in T'Class.
7693 -- end Test;
7695 -- In this case we have nothing else to do. The membership test will be
7696 -- done at run time.
7703 then
7705 else
7709 -- If mixed-mode operations are present and operands are all literal,
7710 -- the only interpretation involves Duration, which is probably not
7711 -- the intention of the programmer.
7726 then
7732 else
7740 ------------------
7741 -- Resolve_Null --
7742 ------------------
7747 begin
7748 -- Handle restriction against anonymous null access values This
7749 -- restriction can be turned off using -gnatdj.
7751 -- Ada 2005 (AI-231): Remove restriction
7754 and then not Debug_Flag_J
7757 then
7758 -- In the common case of a call which uses an explicitly null value
7759 -- for an access parameter, give specialized error message.
7762 Error_Msg_N
7765 -- Standard message for all other cases (are there any?)
7767 else
7768 Error_Msg_N
7773 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
7774 -- assignment to a null-excluding object
7779 then
7781 Insert_Action
7786 else
7793 -- In a distributed context, null for a remote access to subprogram may
7794 -- need to be replaced with a special record aggregate. In this case,
7795 -- return after having done the transformation.
7800 then
7804 -- The null literal takes its type from the context
7809 -----------------------
7810 -- Resolve_Op_Concat --
7811 -----------------------
7815 -- We wish to avoid deep recursion, because concatenations are often
7816 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
7817 -- operands nonrecursively until we find something that is not a simple
7818 -- concatenation (A in this case). We resolve that, and then walk back
7819 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
7820 -- to do the rest of the work at each level. The Parent pointers allow
7821 -- us to avoid recursion, and thus avoid running out of memory. See also
7822 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
7827 begin
7828 -- The following code is equivalent to:
7830 -- Resolve_Op_Concat_First (NN, Typ);
7831 -- Resolve_Op_Concat_Arg (N, ...);
7832 -- Resolve_Op_Concat_Rest (N, Typ);
7834 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
7835 -- operand is a concatenation.
7837 -- Walk down left operands
7839 loop
7848 -- Now (given the above example) NN is A&B and Op1 is A
7850 -- First resolve Op1 ...
7854 -- ... then walk NN back up until we reach N (where we started), calling
7855 -- Resolve_Op_Concat_Rest along the way.
7857 loop
7864 Check_SPARK_Restriction
7869 ---------------------------
7870 -- Resolve_Op_Concat_Arg --
7871 ---------------------------
7873 procedure Resolve_Op_Concat_Arg
7878 is
7882 begin
7884 if Is_Comp
7888 then
7890 else
7894 -- If both Array & Array and Array & Component are visible, there is a
7895 -- potential ambiguity that must be reported.
7900 then
7904 -- If the operation is user-defined and not overloaded use its
7905 -- profile. The operation may be a renaming, in which case it has
7906 -- been rewritten, and we want the original profile.
7911 then
7913 Etype
7917 -- Otherwise an aggregate may match both the array type and the
7918 -- component type.
7920 else
7925 else
7929 then
7930 declare
7935 begin
7940 -- Special-case the error message when the overloading is
7941 -- caused by a function that yields an array and can be
7942 -- called without parameters.
7947 Error_Msg_NE
7949 Error_Msg_NE
7953 else
7961 or else
7963 then
7964 Error_Msg_N -- CODEFIX
7982 else
7987 else
7991 -- Concatenation is restricted in SPARK: each operand must be either a
7992 -- string literal, the name of a string constant, a static character or
7993 -- string expression, or another concatenation. Arg cannot be a
7994 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
7995 -- separately on each final operand, past concatenation operations.
7999 Check_SPARK_Restriction
8007 then
8008 Check_SPARK_Restriction
8012 -- Do not issue error on an operand that is neither a character nor a
8013 -- string, as the error is issued in Resolve_Op_Concat.
8015 else
8022 -----------------------------
8023 -- Resolve_Op_Concat_First --
8024 -----------------------------
8031 begin
8032 -- The parser folds an enormous sequence of concatenations of string
8033 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
8034 -- in the right operand. If the expression resolves to a predefined "&"
8035 -- operator, all is well. Otherwise, the parser's folding is wrong, so
8036 -- we give an error. See P_Simple_Expression in Par.Ch4.
8041 then
8056 ----------------------------
8057 -- Resolve_Op_Concat_Rest --
8058 ----------------------------
8064 begin
8073 -- If this is not a static concatenation, but the result is a string
8074 -- type (and not an array of strings) ensure that static string operands
8075 -- have their subtypes properly constructed.
8079 then
8085 ----------------------
8086 -- Resolve_Op_Expon --
8087 ----------------------
8092 begin
8093 -- Catch attempts to do fixed-point exponentiation with universal
8094 -- operands, which is a case where the illegality is not caught during
8095 -- normal operator analysis.
8105 then
8114 then
8121 then
8125 -- We do the resolution using the base type, because intermediate values
8126 -- in expressions always are of the base type, not a subtype of it.
8140 -- Evaluate the exponentiation operator for dimensioned type
8143 else
8147 -- Set overflow checking bit. Much cleverer code needed here eventually
8148 -- and perhaps the Resolve routines should be separated for the various
8149 -- arithmetic operations, since they will need different processing. ???
8158 --------------------
8159 -- Resolve_Op_Not --
8160 --------------------
8166 -- This function determines if the parent node is a boolean operator or
8167 -- operation (comparison op, membership test, or short circuit form) and
8168 -- the not in question is the left operand of this operation. Note that
8169 -- if the not is in parens, then false is returned.
8171 -----------------------
8172 -- Parent_Is_Boolean --
8173 -----------------------
8176 begin
8180 else
8182 when N_Op_And |
8183 N_Op_Eq |
8184 N_Op_Ge |
8185 N_Op_Gt |
8186 N_Op_Le |
8187 N_Op_Lt |
8188 N_Op_Ne |
8189 N_Op_Or |
8190 N_Op_Xor |
8191 N_In |
8192 N_Not_In |
8193 N_And_Then |
8194 N_Or_Else =>
8204 -- Start of processing for Resolve_Op_Not
8206 begin
8207 -- Predefined operations on scalar types yield the base type. On the
8208 -- other hand, logical operations on arrays yield the type of the
8209 -- arguments (and the context).
8213 else
8220 -- Straightforward case of incorrect arguments
8227 -- Special case of probable missing parens
8231 Error_Msg_N
8234 else
8235 Error_Msg_N
8242 -- OK resolution of NOT
8244 else
8245 -- Warn if non-boolean types involved. This is a case like not a < b
8246 -- where a and b are modular, where we will get (not a) < b and most
8247 -- likely not (a < b) was intended.
8249 if Warn_On_Questionable_Missing_Parens
8251 and then Parent_Is_Boolean
8252 then
8256 -- Warn on double negation if checking redundant constructs
8258 if Warn_On_Redundant_Constructs
8263 then
8267 -- Complete resolution and evaluation of NOT
8277 -----------------------------
8278 -- Resolve_Operator_Symbol --
8279 -----------------------------
8281 -- Nothing to be done, all resolved already
8287 begin
8291 ----------------------------------
8292 -- Resolve_Qualified_Expression --
8293 ----------------------------------
8301 begin
8304 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8305 -- operation if not needed.
8312 then
8313 Check_SPARK_Restriction
8317 -- A qualified expression requires an exact match of the type, class-
8318 -- wide matching is not allowed. However, if the qualifying type is
8319 -- specific and the expression has a class-wide type, it may still be
8320 -- okay, since it can be the result of the expansion of a call to a
8321 -- dispatching function, so we also have to check class-wideness of the
8322 -- type of the expression's original node.
8325 or else
8329 then
8333 -- If the target type is unconstrained, then we reset the type of the
8334 -- result from the type of the expression. For other cases, the actual
8335 -- subtype of the expression is the target type.
8339 then
8347 -------------------
8348 -- Resolve_Range --
8349 -------------------
8356 -- Returns True if N is of the form X'First .. X'Last where X is the
8357 -- same entity for both attributes.
8359 --------------------
8360 -- First_Last_Ref --
8361 --------------------
8367 begin
8372 then
8373 declare
8376 begin
8380 then
8389 -- Start of processing for Resolve_Range
8391 begin
8396 -- Check for inappropriate range on unordered enumeration type
8400 -- Exclude X'First .. X'Last if X is the same entity for both
8402 and then not First_Last_Ref
8403 then
8410 -- We have to check the bounds for being within the base range as
8411 -- required for a non-static context. Normally this is automatic and
8412 -- done as part of evaluating expressions, but the N_Range node is an
8413 -- exception, since in GNAT we consider this node to be a subexpression,
8414 -- even though in Ada it is not. The circuit in Sem_Eval could check for
8415 -- this, but that would put the test on the main evaluation path for
8416 -- expressions.
8421 -- Check for an ambiguous range over character literals. This will
8422 -- happen with a membership test involving only literals.
8430 -- If bounds are static, constant-fold them, so size computations are
8431 -- identical between front-end and back-end. Do not perform this
8432 -- transformation while analyzing generic units, as type information
8433 -- would be lost when reanalyzing the constant node in the instance.
8446 --------------------------
8447 -- Resolve_Real_Literal --
8448 --------------------------
8453 begin
8454 -- Special processing for fixed-point literals to make sure that the
8455 -- value is an exact multiple of small where this is required. We skip
8456 -- this for the universal real case, and also for generic types.
8462 then
8463 declare
8470 begin
8471 -- Case of literal is not an exact multiple of the Small
8475 -- For a source program literal for a decimal fixed-point type,
8476 -- this is statically illegal (RM 4.9(36)).
8481 then
8485 -- Generate a warning if literal from source
8488 and then Warn_On_Bad_Fixed_Value
8489 then
8490 Error_Msg_N
8492 N);
8495 -- Replace literal by a value that is the exact representation
8496 -- of a value of the type, i.e. a multiple of the small value,
8497 -- by truncation, since Machine_Rounds is false for all GNAT
8498 -- fixed-point types (RM 4.9(38)).
8508 -- In all cases, set the corresponding integer field
8514 -- Now replace the actual type by the expected type as usual
8520 -----------------------
8521 -- Resolve_Reference --
8522 -----------------------
8527 begin
8528 -- Replace general access with specific type
8536 -- If we are taking the reference of a volatile entity, then treat it as
8537 -- a potential modification of this entity. This is too conservative,
8538 -- but necessary because remove side effects can cause transformations
8539 -- of normal assignments into reference sequences that otherwise fail to
8540 -- notice the modification.
8547 --------------------------------
8548 -- Resolve_Selected_Component --
8549 --------------------------------
8564 -- Check whether this is the initialization of a component within an
8565 -- init proc (by assignment or call to another init proc). If true,
8566 -- there is no need for a discriminant check.
8568 --------------------
8569 -- Init_Component --
8570 --------------------
8573 begin
8574 return Inside_Init_Proc
8580 -- Start of processing for Resolve_Selected_Component
8582 begin
8585 -- Use the context type to select the prefix that has a selector
8586 -- of the correct name and type.
8594 else
8598 -- Locate selected component. For a private prefix the selector
8599 -- can denote a discriminant.
8603 -- The visible components of a class-wide type are those of
8604 -- the root type.
8614 then
8621 else
8625 Error_Msg_N
8630 else
8633 -- There may be an implicit dereference. Retrieve
8634 -- designated record type.
8638 else
8644 -- Resolution chooses the new interpretation.
8645 -- Find the component with the right name.
8650 loop
8671 else
8672 -- Resolve prefix with its type
8677 -- Generate cross-reference. We needed to wait until full overloading
8678 -- resolution was complete to do this, since otherwise we can't tell if
8679 -- we are an lvalue or not.
8683 else
8687 -- If prefix is an access type, the node will be transformed into an
8688 -- explicit dereference during expansion. The type of the node is the
8689 -- designated type of that of the prefix.
8694 else
8705 and then not Init_Component
8706 then
8714 -- If the prefix is a record conversion, this may be a renamed
8715 -- discriminant whose bounds differ from those of the original
8716 -- one, so we must ensure that a range check is performed.
8721 then
8725 -- Note: No Eval processing is required, because the prefix is of a
8726 -- record type, or protected type, and neither can possibly be static.
8728 -- If the array type is atomic, and is packed, and we are in a left side
8729 -- context, then this is worth a warning, since we have a situation
8730 -- where the access to the component may cause extra read/writes of the
8731 -- atomic array object, which could be considered unexpected.
8739 then
8740 Error_Msg_N
8742 Error_Msg_N
8749 -------------------
8750 -- Resolve_Shift --
8751 -------------------
8758 begin
8759 -- We do the resolution using the base type, because intermediate values
8760 -- in expressions always are of the base type, not a subtype of it.
8773 ---------------------------
8774 -- Resolve_Short_Circuit --
8775 ---------------------------
8782 begin
8786 -- Check for issuing warning for always False assert/check, this happens
8787 -- when assertions are turned off, in which case the pragma Assert/Check
8788 -- was transformed into:
8790 -- if False and then <condition> then ...
8792 -- and we detect this pattern
8794 if Warn_On_Assertion_Failure
8801 then
8802 declare
8805 begin
8808 then
8809 -- Don't want to warn if original condition is explicit False
8811 declare
8813 Original_Node
8814 (Expression
8816 begin
8819 then
8821 else
8822 -- Issue warning. We do not want the deletion of the
8823 -- IF/AND-THEN to take this message with it. We achieve
8824 -- this by making sure that the expanded code points to
8825 -- the Sloc of the expression, not the original pragma.
8827 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
8828 -- The source location of the expression is not usually
8829 -- the best choice here. For example, it gets located on
8830 -- the last AND keyword in a chain of boolean expressiond
8831 -- AND'ed together. It is best to put the message on the
8832 -- first character of the assertion, which is the effect
8833 -- of the First_Node call here.
8835 Error_Msg_F
8837 Expression
8842 -- Similar processing for Check pragma
8846 then
8847 -- Don't want to warn if original condition is explicit False
8849 declare
8851 Original_Node
8852 (Expression
8855 begin
8858 then
8861 -- Post warning
8863 else
8864 -- Again use Error_Msg_F rather than Error_Msg_N, see
8865 -- comment above for an explanation of why we do this.
8867 Error_Msg_F
8869 Expression
8877 -- Continue with processing of short circuit
8886 -------------------
8887 -- Resolve_Slice --
8888 -------------------
8896 begin
8899 -- Use the context type to select the prefix that yields the correct
8900 -- array type.
8902 declare
8909 begin
8917 then
8925 else
8930 else
8941 else
8951 -- If the prefix is an access to an unconstrained array, we must use
8952 -- the actual subtype of the object to perform the index checks. The
8953 -- object denoted by the prefix is implicit in the node, so we build
8954 -- an explicit representation for it in order to compute the actual
8955 -- subtype.
8960 declare
8964 begin
8975 then
8978 -- If the name is a selected component that depends on discriminants,
8979 -- build an actual subtype for it. This can happen only when the name
8980 -- itself is overloaded; otherwise the actual subtype is created when
8981 -- the selected component is analyzed.
8984 and then Full_Analysis
8986 then
8987 declare
8990 begin
8995 -- Maybe this should just be "else", instead of checking for the
8996 -- specific case of slice??? This is needed for the case where the
8997 -- prefix is an Image attribute, which gets expanded to a slice, and so
8998 -- has a constrained subtype which we want to use for the slice range
8999 -- check applied below (the range check won't get done if the
9000 -- unconstrained subtype of the 'Image is used).
9006 -- If name was overloaded, set slice type correctly now
9010 -- If the range is specified by a subtype mark, no resolution is
9011 -- necessary. Else resolve the bounds, and apply needed checks.
9016 else
9024 -- Ensure that side effects in the bounds are properly handled
9029 -- Do not apply the range check to nodes associated with the
9030 -- frontend expansion of the dispatch table. We first check
9031 -- if Ada.Tags is already loaded to avoid the addition of an
9032 -- undesired dependence on such run-time unit.
9034 if not Tagged_Type_Expansion
9035 or else not
9041 then
9049 -- Check bad use of type with predicates
9052 Bad_Predicated_Subtype_Use
9056 -- Otherwise here is where we check suspicious indexes
9067 ----------------------------
9068 -- Resolve_String_Literal --
9069 ----------------------------
9080 begin
9081 -- For a string appearing in a concatenation, defer creation of the
9082 -- string_literal_subtype until the end of the resolution of the
9083 -- concatenation, because the literal may be constant-folded away. This
9084 -- is a useful optimization for long concatenation expressions.
9086 -- If the string is an aggregate built for a single character (which
9087 -- happens in a non-static context) or a is null string to which special
9088 -- checks may apply, we build the subtype. Wide strings must also get a
9089 -- string subtype if they come from a one character aggregate. Strings
9090 -- generated by attributes might be static, but it is often hard to
9091 -- determine whether the enclosing context is static, so we generate
9092 -- subtypes for them as well, thus losing some rarer optimizations ???
9093 -- Same for strings that come from a static conversion.
9095 Need_Check :=
9104 -- If the resolving type is itself a string literal subtype, we can just
9105 -- reuse it, since there is no point in creating another.
9111 and then not Need_Check
9113 N_Attribute_Reference,
9114 N_Qualified_Expression,
9115 N_Type_Conversion)
9116 then
9119 -- Otherwise we must create a string literal subtype. Note that the
9120 -- whole idea of string literal subtypes is simply to avoid the need
9121 -- for building a full fledged array subtype for each literal.
9123 else
9129 or else Need_Check
9130 then
9137 then
9143 -- The validity of a null string has been checked in the call to
9144 -- Eval_String_Literal.
9149 -- Always accept string literal with component type Any_Character, which
9150 -- occurs in error situations and in comparisons of literals, both of
9151 -- which should accept all literals.
9156 -- If the type is bit-packed, then we always transform the string
9157 -- literal into a full fledged aggregate.
9162 -- Deal with cases of Wide_Wide_String, Wide_String, and String
9164 else
9165 -- For Standard.Wide_Wide_String, or any other type whose component
9166 -- type is Standard.Wide_Wide_Character, we know that all the
9167 -- characters in the string must be acceptable, since the parser
9168 -- accepted the characters as valid character literals.
9173 -- For the case of Standard.String, or any other type whose component
9174 -- type is Standard.Character, we must make sure that there are no
9175 -- wide characters in the string, i.e. that it is entirely composed
9176 -- of characters in range of type Character.
9178 -- If the string literal is the result of a static concatenation, the
9179 -- test has already been performed on the components, and need not be
9180 -- repeated.
9184 then
9188 -- If we are out of range, post error. This is one of the
9189 -- very few places that we place the flag in the middle of
9190 -- a token, right under the offending wide character. Not
9191 -- quite clear if this is right wrt wide character encoding
9192 -- sequences, but it's only an error message!
9194 Error_Msg
9201 -- For the case of Standard.Wide_String, or any other type whose
9202 -- component type is Standard.Wide_Character, we must make sure that
9203 -- there are no wide characters in the string, i.e. that it is
9204 -- entirely composed of characters in range of type Wide_Character.
9206 -- If the string literal is the result of a static concatenation,
9207 -- the test has already been performed on the components, and need
9208 -- not be repeated.
9212 then
9216 -- If we are out of range, post error. This is one of the
9217 -- very few places that we place the flag in the middle of
9218 -- a token, right under the offending wide character.
9220 -- This is not quite right, because characters in general
9221 -- will take more than one character position ???
9223 Error_Msg
9230 -- If the root type is not a standard character, then we will convert
9231 -- the string into an aggregate and will let the aggregate code do
9232 -- the checking. Standard Wide_Wide_Character is also OK here.
9234 else
9238 -- See if the component type of the array corresponding to the string
9239 -- has compile time known bounds. If yes we can directly check
9240 -- whether the evaluation of the string will raise constraint error.
9241 -- Otherwise we need to transform the string literal into the
9242 -- corresponding character aggregate and let the aggregate code do
9243 -- the checking.
9247 -- Check for the case of full range, where we are definitely OK
9253 -- Here the range is not the complete base type range, so check
9255 declare
9263 begin
9266 then
9272 then
9273 Apply_Compile_Time_Constraint_Error
9285 -- If we got here we meed to transform the string literal into the
9286 -- equivalent qualified positional array aggregate. This is rather
9287 -- heavy artillery for this situation, but it is hard work to avoid.
9289 declare
9294 begin
9295 -- Build the character literals, we give them source locations that
9296 -- correspond to the string positions, which is a bit tricky given
9297 -- the possible presence of wide character escape sequences.
9311 -- Should we have a call to Skip_Wide here ???
9313 -- ??? else
9314 -- Skip_Wide (P);
9322 Expression =>
9329 -----------------------------
9330 -- Resolve_Subprogram_Info --
9331 -----------------------------
9334 begin
9338 -----------------------------
9339 -- Resolve_Type_Conversion --
9340 -----------------------------
9352 -- Set to False to suppress cases where we want to suppress the test
9353 -- for redundancy to avoid possible false positives on this warning.
9355 begin
9356 if not Conv_OK
9358 then
9362 -- If the Operand Etype is Universal_Fixed, then the conversion is
9363 -- never redundant. We need this check because by the time we have
9364 -- finished the rather complex transformation, the conversion looks
9365 -- redundant when it is not.
9370 -- If the operand is marked as Any_Fixed, then special processing is
9371 -- required. This is also a case where we suppress the test for a
9372 -- redundant conversion, since most certainly it is not redundant.
9377 -- Mixed-mode operation involving a literal. Context must be a fixed
9378 -- type which is applied to the literal subsequently.
9386 or else
9388 then
9389 -- Return if expression is ambiguous
9394 -- If nothing else, the available fixed type is Duration
9396 else
9400 -- Resolve the real operand with largest available precision
9404 else
9410 -- If the operand is a literal (it could be a non-static and
9411 -- illegal exponentiation) check whether the use of Duration
9412 -- is potentially inaccurate.
9417 then
9418 Error_Msg_N
9421 Rop);
9422 Error_Msg_N
9429 then
9432 else
9441 -- In SPARK, a type conversion between array types should be restricted
9442 -- to types which have matching static bounds.
9444 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9445 -- operation if not needed.
9452 then
9453 Check_SPARK_Restriction
9457 -- In formal mode, the operand of an ancestor type conversion must be an
9458 -- object (not an expression).
9466 then
9472 -- Note: we do the Eval_Type_Conversion call before applying the
9473 -- required checks for a subtype conversion. This is important, since
9474 -- both are prepared under certain circumstances to change the type
9475 -- conversion to a constraint error node, but in the case of
9476 -- Eval_Type_Conversion this may reflect an illegality in the static
9477 -- case, and we would miss the illegality (getting only a warning
9478 -- message), if we applied the type conversion checks first.
9482 -- Even when evaluation is not possible, we may be able to simplify the
9483 -- conversion or its expression. This needs to be done before applying
9484 -- checks, since otherwise the checks may use the original expression
9485 -- and defeat the simplifications. This is specifically the case for
9486 -- elimination of the floating-point Truncation attribute in
9487 -- float-to-int conversions.
9491 -- If after evaluation we still have a type conversion, then we may need
9492 -- to apply checks required for a subtype conversion.
9494 -- Skip these type conversion checks if universal fixed operands
9495 -- operands involved, since range checks are handled separately for
9496 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
9502 then
9506 -- Issue warning for conversion of simple object to its own type. We
9507 -- have to test the original nodes, since they may have been rewritten
9508 -- by various optimizations.
9512 -- Here we test for a redundant conversion if the warning mode is
9513 -- active (and was not locally reset), and we have a type conversion
9514 -- from source not appearing in a generic instance.
9516 if Test_Redundant
9519 and then not In_Instance
9520 then
9524 -- If the node is part of a larger expression, the Target_Type
9525 -- may not be the original type of the node if the context is a
9526 -- condition. Recover original type to see if conversion is needed.
9530 then
9534 -- If we have an entity name, then give the warning if the entity
9535 -- is the right type, or if it is a loop parameter covered by the
9536 -- original type (that's needed because loop parameters have an
9537 -- odd subtype coming from the bounds).
9540 and then
9542 or else
9546 -- If not an entity, then type of expression must match
9549 then
9550 -- One more check, do not give warning if the analyzed conversion
9551 -- has an expression with non-static bounds, and the bounds of the
9552 -- target are static. This avoids junk warnings in cases where the
9553 -- conversion is necessary to establish staticness, for example in
9554 -- a case statement.
9558 then
9561 -- Finally, if this type conversion occurs in a context requiring
9562 -- a prefix, and the expression is a qualified expression then the
9563 -- type conversion is not redundant, since a qualified expression
9564 -- is not a prefix, whereas a type conversion is. For example, "X
9565 -- := T'(Funx(...)).Y;" is illegal because a selected component
9566 -- requires a prefix, but a type conversion makes it legal: "X :=
9567 -- T(T'(Funx(...))).Y;"
9569 -- In Ada 2012, a qualified expression is a name, so this idiom is
9570 -- no longer needed, but we still suppress the warning because it
9571 -- seems unfriendly for warnings to pop up when you switch to the
9572 -- newer language version.
9576 N_Indexed_Component,
9577 N_Selected_Component,
9578 N_Slice,
9579 N_Explicit_Dereference)
9580 then
9583 -- Here we give the redundant conversion warning. If it is an
9584 -- entity, give the name of the entity in the message. If not,
9585 -- just mention the expression.
9587 else
9590 Error_Msg_NE -- CODEFIX
9593 else
9594 Error_Msg_NE
9602 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
9603 -- No need to perform any interface conversion if the type of the
9604 -- expression coincides with the target type.
9607 and then Full_Expander_Active
9609 then
9610 declare
9614 begin
9626 -- Conversion from interface type
9630 -- Ada 2005 (AI-217): Handle entities from limited views
9634 Error_Msg_NE -- CODEFIX
9637 Error_Msg_N
9639 N);
9642 and then not
9645 then
9647 Error_Msg_NE -- CODEFIX
9650 Error_Msg_N
9652 N);
9654 else
9658 -- Conversion to interface type
9662 -- Handle subtypes
9668 if not Interface_Present_In_Ancestor
9671 then
9674 -- The static analysis is not enough to know if the
9675 -- interface is implemented or not. Hence we must pass
9676 -- the work to the expander to generate code to evaluate
9677 -- the conversion at run time.
9681 else
9684 Error_Msg_N
9689 else
9697 ----------------------
9698 -- Resolve_Unary_Op --
9699 ----------------------
9708 begin
9711 Check_SPARK_Restriction
9715 -- Deal with intrinsic unary operators
9721 then
9726 -- Deal with universal cases
9729 or else
9731 then
9738 -- Generate warning for expressions like abs (x mod 2)
9740 if Warn_On_Redundant_Constructs
9742 then
9746 Error_Msg_N -- CODEFIX
9751 -- Deal with reference generation
9758 -- Set overflow checking bit. Much cleverer code needed here eventually
9759 -- and perhaps the Resolve routines should be separated for the various
9760 -- arithmetic operations, since they will need different processing ???
9768 -- Generate warning for expressions like -5 mod 3 for integers. No need
9769 -- to worry in the floating-point case, since parens do not affect the
9770 -- result so there is no point in giving in a warning.
9772 declare
9781 begin
9782 if Warn_On_Questionable_Missing_Parens
9786 then
9789 -- We are looking for cases where the right operand is not
9790 -- parenthesized, and is a binary operator, multiply, divide, or
9791 -- mod. These are the cases where the grouping can affect results.
9795 then
9796 -- For mod, we always give the warning, since the value is
9797 -- affected by the parenthesization (e.g. (-5) mod 315 /=
9798 -- -(5 mod 315)). But for the other cases, the only concern is
9799 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
9800 -- overflows, but (-2) * 64 does not). So we try to give the
9801 -- message only when overflow is possible.
9805 then
9810 else
9816 else
9820 -- Note that the test below is deliberately excluding the
9821 -- largest negative number, since that is a potentially
9822 -- troublesome case (e.g. -2 * x, where the result is the
9823 -- largest negative integer has an overflow with 2 * x).
9830 -- For the multiplication case, the only case we have to worry
9831 -- about is when (-a)*b is exactly the largest negative number
9832 -- so that -(a*b) can cause overflow. This can only happen if
9833 -- a is a power of 2, and more generally if any operand is a
9834 -- constant that is not a power of 2, then the parentheses
9835 -- cannot affect whether overflow occurs. We only bother to
9836 -- test the left most operand
9838 -- Loop looking at left operands for one that has known value
9845 -- Operand value of 0 or 1 skips warning
9850 -- Otherwise check power of 2, if power of 2, warn, if
9851 -- anything else, skip warning.
9853 else
9857 else
9866 -- Keep looking at left operands
9871 -- For rem or "/" we can only have a problematic situation
9872 -- if the divisor has a value of minus one or one. Otherwise
9873 -- overflow is impossible (divisor > 1) or we have a case of
9874 -- division by zero in any case.
9879 then
9883 -- If we fall through warning should be issued
9885 Error_Msg_N
9892 ----------------------------------
9893 -- Resolve_Unchecked_Expression --
9894 ----------------------------------
9896 procedure Resolve_Unchecked_Expression
9899 is
9900 begin
9905 ---------------------------------------
9906 -- Resolve_Unchecked_Type_Conversion --
9907 ---------------------------------------
9909 procedure Resolve_Unchecked_Type_Conversion
9912 is
9918 begin
9919 -- Resolve operand using its own type
9926 ------------------------------
9927 -- Rewrite_Operator_As_Call --
9928 ------------------------------
9935 begin
9942 New_N :=
9953 ------------------------------
9954 -- Rewrite_Renamed_Operator --
9955 ------------------------------
9957 procedure Rewrite_Renamed_Operator
9961 is
9966 begin
9967 -- Rewrite the operator node using the real operator, not its renaming.
9968 -- Exclude user-defined intrinsic operations of the same name, which are
9969 -- treated separately and rewritten as calls.
9978 -- Indicate that both the original entity and its renaming are
9979 -- referenced at this point.
9990 -- If the context type is private, add the appropriate conversions so
9991 -- that the operator is applied to the full view. This is done in the
9992 -- routines that resolve intrinsic operators.
9996 then
9998 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
9999 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
10012 -- Operator renames a user-defined operator of the same name. Use the
10013 -- original operator in the node, which is the one Gigi knows about.
10020 -----------------------
10021 -- Set_Slice_Subtype --
10022 -----------------------
10024 -- Build an implicit subtype declaration to represent the type delivered by
10025 -- the slice. This is an abbreviated version of an array subtype. We define
10026 -- an index subtype for the slice, using either the subtype name or the
10027 -- discrete range of the slice. To be consistent with index usage elsewhere
10028 -- we create a list header to hold the single index. This list is not
10029 -- otherwise attached to the syntax tree.
10040 begin
10044 else
10045 -- We force the evaluation of a range. This is definitely needed in
10046 -- the renamed case, and seems safer to do unconditionally. Note in
10047 -- any case that since we will create and insert an Itype referring
10048 -- to this range, we must make sure any side effect removal actions
10049 -- are inserted before the Itype definition.
10060 -- Take a new copy of Drange (where bounds have been rewritten to
10061 -- reference side-effect-free names). Using a separate tree ensures
10062 -- that further expansion (e.g. while rewriting a slice assignment
10063 -- into a FOR loop) does not attempt to remove side effects on the
10064 -- bounds again (which would cause the bounds in the index subtype
10065 -- definition to refer to temporaries before they are defined) (the
10066 -- reason is that some names are considered side effect free here
10067 -- for the subtype, but not in the context of a loop iteration
10068 -- scheme).
10089 -- The Etype of the existing Slice node is reset to this slice subtype.
10090 -- Its bounds are obtained from its first index.
10094 -- For packed slice subtypes, freeze immediately (except in the case of
10095 -- being in a "spec expression" where we never freeze when we first see
10096 -- the expression).
10101 -- For all other cases insert an itype reference in the slice's actions
10102 -- so that the itype is frozen at the proper place in the tree (i.e. at
10103 -- the point where actions for the slice are analyzed). Note that this
10104 -- is different from freezing the itype immediately, which might be
10105 -- premature (e.g. if the slice is within a transient scope). This needs
10106 -- to be done only if expansion is enabled.
10113 --------------------------------
10114 -- Set_String_Literal_Subtype --
10115 --------------------------------
10123 begin
10135 -- The low bound is set from the low bound of the corresponding index
10136 -- type. Note that we do not store the high bound in the string literal
10137 -- subtype, but it can be deduced if necessary from the length and the
10138 -- low bound.
10143 -- If the lower bound is not static we create a range for the string
10144 -- literal, using the index type and the known length of the literal.
10145 -- The index type is not necessarily Positive, so the upper bound is
10146 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
10148 else
10149 declare
10155 Prefix =>
10159 Left_Opnd =>
10162 Prefix =>
10164 Expressions =>
10166 Right_Opnd =>
10175 begin
10177 Set_String_Literal_Low_Bound
10180 else
10181 -- If the index type is an enumeration type, build bounds
10182 -- expression with attributes.
10184 Set_String_Literal_Low_Bound
10188 Prefix =>
10195 -- Build bona fide subtype for the string, and wrap it in an
10196 -- unchecked conversion, because the backend expects the
10197 -- String_Literal_Subtype to have a static lower bound.
10199 Index_Subtype :=
10206 -- In the context, the Index_Type may already have a constraint,
10207 -- so use common base type on string subtype. The base type may
10208 -- be used when generating attributes of the string, for example
10209 -- in the context of a slice assignment.
10234 ------------------------------
10235 -- Simplify_Type_Conversion --
10236 ------------------------------
10239 begin
10241 declare
10246 begin
10248 and then
10255 -- Special processing required if the conversion is the expression
10256 -- of a Truncation attribute reference. In this case we replace:
10258 -- ityp (ftyp'Truncation (x))
10260 -- by
10262 -- ityp (x)
10264 -- with the Float_Truncate flag set, which is more efficient.
10266 then
10275 -----------------------------
10276 -- Unique_Fixed_Point_Type --
10277 -----------------------------
10286 -- Give error messages for true ambiguity. Messages are posted on node
10287 -- N, and entities T1, T2 are the possible interpretations.
10289 -----------------------
10290 -- Fixed_Point_Error --
10291 -----------------------
10294 begin
10300 -- Start of processing for Unique_Fixed_Point_Type
10302 begin
10303 -- The operations on Duration are visible, so Duration is always a
10304 -- possible interpretation.
10308 -- Look for fixed-point types in enclosing scopes
10317 then
10319 Fixed_Point_Error;
10321 else
10332 -- Look for visible fixed type declarations in the context
10343 then
10345 Fixed_Point_Error;
10347 else
10361 else
10368 ----------------------
10369 -- Valid_Conversion --
10370 ----------------------
10372 function Valid_Conversion
10377 is
10381 function Conversion_Check
10384 -- Little routine to post Msg if Valid is False, returns Valid value
10386 -- The following are badly named, this kind of overloading is actively
10387 -- confusing in reading code, please rename to something like
10388 -- Error_Msg_N_If_Reporting ???
10391 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
10393 procedure Error_Msg_NE
10397 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
10399 function Valid_Tagged_Conversion
10402 -- Specifically test for validity of tagged conversions
10405 -- Check index and component conformance, and accessibility levels if
10406 -- the component types are anonymous access types (Ada 2005).
10408 ----------------------
10409 -- Conversion_Check --
10410 ----------------------
10412 function Conversion_Check
10415 is
10416 begin
10417 if not Valid
10419 -- A generic unit has already been analyzed and we have verified
10420 -- that a particular conversion is OK in that context. Since the
10421 -- instance is reanalyzed without relying on the relationships
10422 -- established during the analysis of the generic, it is possible
10423 -- to end up with inconsistent views of private types. Do not emit
10424 -- the error message in such cases. The rest of the machinery in
10425 -- Valid_Conversion still ensures the proper compatibility of
10426 -- target and operand types.
10428 and then not In_Instance
10429 then
10436 -----------------
10437 -- Error_Msg_N --
10438 -----------------
10441 begin
10447 ------------------
10448 -- Error_Msg_NE --
10449 ------------------
10451 procedure Error_Msg_NE
10455 is
10456 begin
10462 ----------------------------
10463 -- Valid_Array_Conversion --
10464 ----------------------------
10467 is
10482 begin
10483 -- Error if wrong number of dimensions
10485 if
10487 then
10488 Error_Msg_N
10492 -- Number of dimensions matches
10494 else
10495 -- Loop through indexes of the two arrays
10503 -- Error if index types are incompatible
10509 then
10510 Error_Msg_N
10512 Operand);
10520 -- If component types have same base type, all set
10525 -- Here if base types of components are not the same. The only
10526 -- time this is allowed is if we have anonymous access types.
10528 -- The conversion of arrays of anonymous access types can lead
10529 -- to dangling pointers. AI-392 formalizes the accessibility
10530 -- checks that must be applied to such conversions to prevent
10531 -- out-of-scope references.
10533 elsif Ekind_In
10535 E_Anonymous_Access_Subprogram_Type)
10537 and then
10539 then
10542 then
10544 Error_Msg_N
10547 Error_Msg_N
10549 Operand);
10556 -- Conversion not allowed because of accessibility levels
10558 else
10559 Error_Msg_N
10565 else
10569 -- All other cases where component base types do not match
10571 else
10572 Error_Msg_N
10574 Operand);
10578 -- Check that component subtypes statically match. For numeric
10579 -- types this means that both must be either constrained or
10580 -- unconstrained. For enumeration types the bounds must match.
10581 -- All of this is checked in Subtypes_Statically_Match.
10583 if not Subtypes_Statically_Match
10585 then
10586 Error_Msg_N
10595 -----------------------------
10596 -- Valid_Tagged_Conversion --
10597 -----------------------------
10599 function Valid_Tagged_Conversion
10602 is
10603 begin
10604 -- Upward conversions are allowed (RM 4.6(22))
10608 then
10611 -- Downward conversion are allowed if the operand is class-wide
10612 -- (RM 4.6(23)).
10616 then
10621 then
10622 return
10626 -- Ada 2005 (AI-251): The conversion to/from interface types is
10627 -- always valid
10632 -- If the operand is a class-wide type obtained through a limited_
10633 -- with clause, and the context includes the non-limited view, use
10634 -- it to determine whether the conversion is legal.
10640 then
10645 then
10648 else
10649 Error_Msg_NE
10656 -- Start of processing for Valid_Conversion
10658 begin
10662 declare
10670 begin
10671 -- Remove procedure calls, which syntactically cannot appear in
10672 -- this context, but which cannot be removed by type checking,
10673 -- because the context does not impose a type.
10675 -- When compiling for VMS, spurious ambiguities can be produced
10676 -- when arithmetic operations have a literal operand and return
10677 -- System.Address or a descendant of it. These ambiguities are
10678 -- otherwise resolved by the context, but for conversions there
10679 -- is no context type and the removal of the spurious operations
10680 -- must be done explicitly here.
10682 -- The node may be labelled overloaded, but still contain only one
10683 -- interpretation because others were discarded earlier. If this
10684 -- is the case, retain the single interpretation if legal.
10692 then
10693 -- More than one candidate interpretation is available
10703 then
10730 -- If the interpretation involves a standard operator, use
10731 -- the location of the type, which may be user-defined.
10735 else
10739 Error_Msg_N -- CODEFIX
10744 else
10748 Error_Msg_N -- CODEFIX
10760 -- Numeric types
10764 -- A universal fixed expression can be converted to any numeric type
10769 -- Also no need to check when in an instance or inlined body, because
10770 -- the legality has been established when the template was analyzed.
10771 -- Furthermore, numeric conversions may occur where only a private
10772 -- view of the operand type is visible at the instantiation point.
10773 -- This results in a spurious error if we check that the operand type
10774 -- is a numeric type.
10776 -- Note: in a previous version of this unit, the following tests were
10777 -- applied only for generated code (Comes_From_Source set to False),
10778 -- but in fact the test is required for source code as well, since
10779 -- this situation can arise in source code.
10784 -- Otherwise we need the conversion check
10786 else
10787 return Conversion_Check
10792 -- Array types
10798 then
10801 else
10805 -- Ada 2005 (AI-251): Anonymous access types where target references an
10806 -- interface type.
10809 E_Anonymous_Access_Type)
10811 then
10812 -- Check the static accessibility rule of 4.6(17). Note that the
10813 -- check is not enforced when within an instance body, since the
10814 -- RM requires such cases to be caught at run time.
10816 -- If the operand is a rewriting of an allocator no check is needed
10817 -- because there are no accessibility issues.
10825 then
10826 -- In an instance, this is a run-time check, but one we know
10827 -- will fail, so generate an appropriate warning. The raise
10828 -- will be generated by Expand_N_Type_Conversion.
10831 Error_Msg_N
10833 Operand);
10834 Error_Msg_N
10837 else
10838 Error_Msg_N
10840 Operand);
10844 -- Special accessibility checks are needed in the case of access
10845 -- discriminants declared for a limited type.
10849 then
10850 -- When the operand is a selected access discriminant the check
10851 -- needs to be made against the level of the object denoted by
10852 -- the prefix of the selected name (Object_Access_Level handles
10853 -- checking the prefix of the operand for this case).
10858 then
10859 -- In an instance, this is a run-time check, but one we know
10860 -- will fail, so generate an appropriate warning. The raise
10861 -- will be generated by Expand_N_Type_Conversion.
10864 Error_Msg_N
10867 Error_Msg_N
10869 else
10870 Error_Msg_N
10877 -- The case of a reference to an access discriminant from
10878 -- within a limited type declaration (which will appear as
10879 -- a discriminal) is always illegal because the level of the
10880 -- discriminant is considered to be deeper than any (nameable)
10881 -- access type.
10885 and then
10888 then
10889 Error_Msg_N
10891 Operand);
10899 -- General and anonymous access types
10902 E_Anonymous_Access_Type)
10903 and then
10904 Conversion_Check
10906 and then not
10908 E_Access_Protected_Subprogram_Type),
10910 then
10913 then
10914 Error_Msg_N
10919 -- Check the static accessibility rule of 4.6(17). Note that the
10920 -- check is not enforced when within an instance body, since the RM
10921 -- requires such cases to be caught at run time.
10926 N_Object_Declaration
10927 then
10928 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
10929 -- conversions from an anonymous access type to a named general
10930 -- access type. Such conversions are not allowed in the case of
10931 -- access parameters and stand-alone objects of an anonymous
10932 -- access type. The implicit conversion case is recognized by
10933 -- testing that Comes_From_Source is False and that it's been
10934 -- rewritten. The Comes_From_Source test isn't sufficient because
10935 -- nodes in inlined calls to predefined library routines can have
10936 -- Comes_From_Source set to False. (Is there a better way to test
10937 -- for implicit conversions???)
10944 then
10947 -- Implicit conversions aren't allowed for objects of an
10948 -- anonymous access type, since such objects have nonstatic
10949 -- levels in Ada 2012.
10952 N_Object_Declaration
10953 then
10954 Error_Msg_N
10959 -- Implicit conversions aren't allowed for anonymous access
10960 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
10961 -- is done to exclude anonymous access results.
10965 N_Function_Specification,
10966 N_Procedure_Specification)
10967 then
10968 Error_Msg_N
10973 -- This is a case where there's an enclosing object whose
10974 -- to which the "statically deeper than" relationship does
10975 -- not apply (such as an access discriminant selected from
10976 -- a dereference of an access parameter).
10980 then
10981 Error_Msg_N
10986 -- In other cases, the level of the operand's type must be
10987 -- statically less deep than that of the target type, else
10988 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
10992 then
10993 Error_Msg_N
11002 then
11003 -- In an instance, this is a run-time check, but one we know
11004 -- will fail, so generate an appropriate warning. The raise
11005 -- will be generated by Expand_N_Type_Conversion.
11008 Error_Msg_N
11010 Operand);
11011 Error_Msg_N
11014 else
11015 -- Avoid generation of spurious error message
11018 Error_Msg_N
11020 Operand);
11026 -- Special accessibility checks are needed in the case of access
11027 -- discriminants declared for a limited type.
11031 then
11032 -- When the operand is a selected access discriminant the check
11033 -- needs to be made against the level of the object denoted by
11034 -- the prefix of the selected name (Object_Access_Level handles
11035 -- checking the prefix of the operand for this case).
11040 then
11041 -- In an instance, this is a run-time check, but one we know
11042 -- will fail, so generate an appropriate warning. The raise
11043 -- will be generated by Expand_N_Type_Conversion.
11046 Error_Msg_N
11049 Error_Msg_N
11051 Operand);
11053 else
11054 Error_Msg_N
11061 -- The case of a reference to an access discriminant from
11062 -- within a limited type declaration (which will appear as
11063 -- a discriminal) is always illegal because the level of the
11064 -- discriminant is considered to be deeper than any (nameable)
11065 -- access type.
11068 and then
11071 then
11072 Error_Msg_N
11074 Operand);
11080 -- In the presence of limited_with clauses we have to use non-limited
11081 -- views, if available.
11085 -- Helper function to handle limited views
11087 --------------------------
11088 -- Full_Designated_Type --
11089 --------------------------
11094 begin
11095 -- Handle the limited view of a type
11100 then
11102 else
11107 -- Local Declarations
11115 -- Start of processing for Check_Limited
11117 begin
11121 else
11123 Error_Msg_NE
11128 -- Ada 2005 AI-384: legality rule is symmetric in both
11129 -- designated types. The conversion is legal (with possible
11130 -- constraint check) if either designated type is
11131 -- unconstrained.
11134 or else
11136 and then
11139 then
11140 -- Special case, if Value_Size has been used to make the
11141 -- sizes different, the conversion is not allowed even
11142 -- though the subtypes statically match.
11147 then
11148 Error_Msg_NE
11151 Error_Msg_NE
11156 -- Normal case where conversion is allowed
11158 else
11162 else
11163 Error_Msg_NE
11171 -- Access to subprogram types. If the operand is an access parameter,
11172 -- the type has a deeper accessibility that any master, and cannot be
11173 -- assigned. We must make an exception if the conversion is part of an
11174 -- assignment and the target is the return object of an extended return
11175 -- statement, because in that case the accessibility check takes place
11176 -- after the return.
11180 then
11184 and then
11188 then
11189 Error_Msg_N
11191 Operand);
11192 Error_Msg_N
11195 Operand);
11197 Error_Msg_NE
11202 -- Check that the designated types are subtype conformant
11208 -- Check the static accessibility rule of 4.6(20)
11212 then
11213 Error_Msg_N
11215 Operand);
11217 -- Check that if the operand type is declared in a generic body,
11218 -- then the target type must be declared within that same body
11219 -- (enforces last sentence of 4.6(20)).
11222 declare
11228 begin
11235 Error_Msg_N
11244 -- Remote subprogram access types
11248 then
11249 -- It is valid to convert from one RAS type to another provided
11250 -- that their specification statically match.
11252 Check_Subtype_Conformant
11255 Old_Id =>
11257 Err_Loc =>
11258 N);
11261 -- If it was legal in the generic, it's legal in the instance
11266 -- If both are tagged types, check legality of view conversions
11269 and then
11271 then
11274 -- Types derived from the same root type are convertible
11279 -- In an instance or an inlined body, there may be inconsistent views of
11280 -- the same type, or of types derived from a common root.
11283 and then
11286 then
11289 -- Special check for common access type error case
11293 then
11295 Error_Msg_NE -- CODEFIX
11299 else