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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) 1992-2013, 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 -- Versions with 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_If_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 this is a package renaming, get renamed entity, which will be
1355 -- the scope of the operands if operaton is type-correct.
1361 -- If the entity being called is defined in the given package, it is
1362 -- a renaming of a predefined operator, and known to be legal.
1366 then
1369 -- Visibility does not need to be checked in an instance: if the
1370 -- operator was not visible in the generic it has been diagnosed
1371 -- already, else there is an implicit copy of it in the instance.
1379 then
1384 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1385 -- available.
1390 then
1393 else
1402 and then Is_Binary
1404 then
1410 -- Verify that the scope contains a type that corresponds to
1411 -- the given literal. Optimize the case where Pack is Standard.
1433 else
1442 else
1451 then
1454 -- If the type is defined elsewhere, and the operator is not
1455 -- defined in the given scope (by a renaming declaration, e.g.)
1456 -- then this is an error as well. If an extension of System is
1457 -- present, and the type may be defined there, Pack must be
1458 -- System itself.
1465 then
1468 else
1474 then
1481 Error_Msg_NE
1486 -- Detect a mismatch between the context type and the result type
1487 -- in the named package, which is otherwise not detected if the
1488 -- operands are universal. Check is only needed if source entity is
1489 -- an operator, not a function that renames an operator.
1496 and then not In_Instance
1497 then
1500 or else
1502 then
1503 -- Already checked above
1507 -- Operator may be defined in an extension of System
1511 then
1514 else
1515 -- Could we use Wrong_Type here??? (this would require setting
1516 -- Etype (N) to the actual type found where Typ was expected).
1527 else
1531 -- If this is a call to a function that renames a predefined equality,
1532 -- the renaming declaration provides a type that must be used to
1533 -- resolve the operands. This must be done now because resolution of
1534 -- the equality node will not resolve any remaining ambiguity, and it
1535 -- assumes that the first operand is not overloaded.
1540 then
1548 -- Do rewrite setting Comes_From_Source on the result if the original
1549 -- call came from source. Although it is not strictly the case that the
1550 -- operator as such comes from the source, logically it corresponds
1551 -- exactly to the function call in the source, so it should be marked
1552 -- this way (e.g. to make sure that validity checks work fine).
1554 declare
1556 begin
1561 -- If this is an arithmetic operator and the result type is private,
1562 -- the operands and the result must be wrapped in conversion to
1563 -- expose the underlying numeric type and expand the proper checks,
1564 -- e.g. on division.
1568 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1569 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1578 else
1583 -------------------
1584 -- Operator_Kind --
1585 -------------------
1587 function Operator_Kind
1590 is
1593 begin
1594 -- Use CASE statement or array???
1631 else
1635 -- Unary operators
1637 else
1646 else
1654 ----------------------------
1655 -- Preanalyze_And_Resolve --
1656 ----------------------------
1661 begin
1665 -- Normally, we suppress all checks for this preanalysis. There is no
1666 -- point in processing them now, since they will be applied properly
1667 -- and in the proper location when the default expressions reanalyzed
1668 -- and reexpanded later on. We will also have more information at that
1669 -- point for possible suppression of individual checks.
1671 -- However, in Alfa mode, most expansion is suppressed, and this
1672 -- later reanalysis and reexpansion may not occur. Alfa mode does
1673 -- require the setting of checking flags for proof purposes, so we
1674 -- do the Alfa preanalysis without suppressing checks.
1676 -- This special handling for Alfa mode is required for example in the
1677 -- case of Ada 2012 constructs such as quantified expressions, which are
1678 -- expanded in two separate steps.
1682 else
1686 Expander_Mode_Restore;
1690 -- Version without context type
1695 begin
1702 Expander_Mode_Restore;
1706 ----------------------------------
1707 -- Replace_Actual_Discriminants --
1708 ----------------------------------
1715 -- Comment needed???
1717 -------------------
1718 -- Process_Discr --
1719 -------------------
1724 begin
1730 then
1746 -- Start of processing for Replace_Actual_Discriminants
1748 begin
1762 else
1767 -------------
1768 -- Resolve --
1769 -------------
1785 -- Determine whether a node comes from a predefined library unit or
1786 -- Standard.
1789 -- Try and fix up a literal so that it matches its expected type. New
1790 -- literals are manufactured if necessary to avoid cascaded errors.
1793 -- Return the current scope. Skip loop scopes created for the purpose of
1794 -- quantified expression analysis since those do not appear in the tree.
1797 -- Additional diagnostics when an ambiguous call has an ambiguous
1798 -- argument (typically a controlling actual).
1801 -- Called when attempt at resolving current expression fails
1803 ------------------------------------
1804 -- Comes_From_Predefined_Lib_Unit --
1805 -------------------------------------
1808 begin
1809 return
1811 or else Is_Predefined_File_Name
1815 --------------------
1816 -- Patch_Up_Value --
1817 --------------------
1820 begin
1837 then
1842 Char_Literal_Value =>
1858 --------------------------
1859 -- Proper_Current_Scope --
1860 --------------------------
1865 begin
1868 -- Skip a loop scope created for quantified expression analysis
1872 then
1874 else
1882 -------------------------------
1883 -- Report_Ambiguous_Argument --
1884 -------------------------------
1891 begin
1895 then
1898 -- Could use comments on what is going on here???
1906 else
1915 -----------------------
1916 -- Resolution_Failed --
1917 -----------------------
1920 begin
1926 -- The caller will return without calling the expander, so we need
1927 -- to set the analyzed flag. Note that it is fine to set Analyzed
1928 -- to True even if we are in the middle of a shallow analysis,
1929 -- (see the spec of sem for more details) since this is an error
1930 -- situation anyway, and there is no point in repeating the
1931 -- analysis later (indeed it won't work to repeat it later, since
1932 -- we haven't got a clear resolution of which entity is being
1933 -- referenced.)
1939 -- Start of processing for Resolve
1941 begin
1946 -- Access attribute on remote subprogram cannot be used for a non-remote
1947 -- access-to-subprogram type.
1958 then
1959 Error_Msg_N
1965 -- If the context is a Remote_Access_To_Subprogram, access attributes
1966 -- must be resolved with the corresponding fat pointer. There is no need
1967 -- to check for the attribute name since the return type of an
1968 -- attribute is never a remote type.
1973 then
1974 declare
1982 begin
1983 -- Check that Typ is a remote access-to-subprogram type
1987 -- Prefix (N) must statically denote a remote subprogram
1988 -- declared in a package specification.
1992 Attr = Attribute_Unrestricted_Access
1993 then
2008 or else
2010 then
2012 Error_Msg_N
2014 N);
2017 -- If we are generating code in distributed mode, perform
2018 -- semantic checks against corresponding remote entities.
2020 if Full_Expander_Active
2022 then
2023 Check_Subtype_Conformant
2025 Old_Id => Designated_Type
2051 then
2056 -- Return if already analyzed
2063 -- Return if type = Any_Type (previous error encountered)
2072 -- If not overloaded, then we know the type, and all that needs doing
2073 -- is to check that this type is compatible with the context.
2079 -- In the overloaded case, we must select the interpretation that
2080 -- is compatible with the context (i.e. the type passed to Resolve)
2082 else
2083 -- Loop through possible interpretations
2093 -- We are only interested in interpretations that are compatible
2094 -- with the expected type, any other interpretations are ignored.
2099 Write_Eol;
2102 else
2103 -- Skip the current interpretation if it is disabled by an
2104 -- abstract operator. This action is performed only when the
2105 -- type against which we are resolving is the same as the
2106 -- type of the interpretation.
2113 then
2121 -- First matching interpretation
2129 -- Matching interpretation that is not the first, maybe an
2130 -- error, but there are some cases where preference rules are
2131 -- used to choose between the two possibilities. These and
2132 -- some more obscure cases are handled in Disambiguate.
2134 else
2135 -- If the current statement is part of a predefined library
2136 -- unit, then all interpretations which come from user level
2137 -- packages should not be considered.
2139 if From_Lib
2141 then
2148 -- Disambiguation has succeeded. Skip the remaining
2149 -- interpretations.
2159 else
2160 -- Before we issue an ambiguity complaint, check for
2161 -- the case of a subprogram call where at least one
2162 -- of the arguments is Any_Type, and if so, suppress
2163 -- the message, since it is a cascaded error.
2166 declare
2170 begin
2182 Write_Eol;
2195 then
2200 then
2204 -- Not that special case, so issue message using the
2205 -- flag Ambiguous to control printing of the header
2206 -- message only at the start of an ambiguous set.
2211 then
2212 Error_Msg_N
2215 else
2216 Error_Msg_NE -- CODEFIX
2224 Error_Msg_N
2226 else
2227 Error_Msg_N -- CODEFIX
2233 then
2234 Report_Ambiguous_Argument;
2240 -- By default, the error message refers to the candidate
2241 -- interpretation. But if it is a predefined operator, it
2242 -- is implicitly declared at the declaration of the type
2243 -- of the operand. Recover the sloc of that declaration
2244 -- for the error message.
2250 Standard_Standard
2251 then
2256 then
2264 Standard_Standard
2265 then
2270 then
2274 -- If this is an indirect call, use the subprogram_type
2275 -- in the message, to have a meaningful location. Also
2276 -- indicate if this is an inherited operation, created
2277 -- by a type declaration.
2282 then
2284 Error_Msg_Sloc :=
2286 else
2293 then
2294 -- Special-case the message for universal_fixed
2295 -- operators, which are not declared with the type
2296 -- of the operand, but appear forever in Standard.
2300 then
2301 Error_Msg_N
2305 else
2306 Error_Msg_N
2310 elsif
2312 then
2313 Error_Msg_N
2315 else
2316 Error_Msg_N -- CODEFIX
2323 -- We have a matching interpretation, Expr_Type is the type
2324 -- from this interpretation, and Seen is the entity.
2326 -- For an operator, just set the entity name. The type will be
2327 -- set by the specific operator resolution routine.
2342 -- AI05-0139-2: Expression is overloaded because type has
2343 -- implicit dereference. If type matches context, no implicit
2344 -- dereference is involved.
2355 then
2358 -- For an explicit dereference, attribute reference, range,
2359 -- short-circuit form (which is not an operator node), or call
2360 -- with a name that is an explicit dereference, there is
2361 -- nothing to be done at this point.
2364 N_Attribute_Reference,
2365 N_And_Then,
2366 N_Indexed_Component,
2367 N_Or_Else,
2368 N_Range,
2369 N_Selected_Component,
2370 N_Slice)
2372 then
2375 -- For procedure or function calls, set the type of the name,
2376 -- and also the entity pointer for the prefix.
2380 then
2387 then
2392 -- For all other cases, just set the type of the Name
2394 else
2402 -- Move to next interpretation
2410 -- At this stage Found indicates whether or not an acceptable
2411 -- interpretation exists. If not, then we have an error, except that if
2412 -- the context is Any_Type as a result of some other error, then we
2413 -- suppress the error report.
2418 -- If type we are looking for is Void, then this is the procedure
2419 -- call case, and the error is simply that what we gave is not a
2420 -- procedure name (we think of procedure calls as expressions with
2421 -- types internally, but the user doesn't think of them this way!)
2425 -- Special case message if function used as a procedure
2430 then
2431 Error_Msg_NE
2435 -- Otherwise give general message (not clear what cases this
2436 -- covers, but no harm in providing for them!)
2438 else
2444 -- Otherwise we do have a subexpression with the wrong type
2446 -- Check for the case of an allocator which uses an access type
2447 -- instead of the designated type. This is a common error and we
2448 -- specialize the message, posting an error on the operand of the
2449 -- allocator, complaining that we expected the designated type of
2450 -- the allocator.
2456 then
2460 -- Check for view mismatch on Null in instances, for which the
2461 -- view-swapping mechanism has no identifier.
2467 then
2472 -- Check for an aggregate. Sometimes we can get bogus aggregates
2473 -- from misuse of parentheses, and we are about to complain about
2474 -- the aggregate without even looking inside it.
2476 -- Instead, if we have an aggregate of type Any_Composite, then
2477 -- analyze and resolve the component fields, and then only issue
2478 -- another message if we get no errors doing this (otherwise
2479 -- assume that the errors in the aggregate caused the problem).
2483 then
2484 -- Disable expansion in any case. If there is a type mismatch
2485 -- it may be fatal to try to expand the aggregate. The flag
2486 -- would otherwise be set to false when the error is posted.
2490 declare
2492 -- Check one aggregate, and set Found to True if we have a
2493 -- definite error in any of its elements
2496 -- Check one element of aggregate and set Found to True if
2497 -- we definitely have an error in the element.
2499 ----------------
2500 -- Check_Aggr --
2501 ----------------
2506 begin
2519 -- If this is a default-initialized component, then
2520 -- there is nothing to check. The box will be
2521 -- replaced by the appropriate call during late
2522 -- expansion.
2533 ----------------
2534 -- Check_Elmt --
2535 ----------------
2538 begin
2539 -- If we have a nested aggregate, go inside it (to
2540 -- attempt a naked analyze-resolve of the aggregate can
2541 -- cause undesirable cascaded errors). Do not resolve
2542 -- expression if it needs a type from context, as for
2543 -- integer * fixed expression.
2548 else
2553 then
2563 begin
2568 -- If an error message was issued already, Found got reset to
2569 -- True, so if it is still False, issue standard Wrong_Type msg.
2574 then
2575 declare
2577 begin
2583 -- Protected operation: retrieve operation name
2587 else
2597 declare
2601 begin
2608 Error_Msg_NE
2614 else
2618 else
2624 Resolution_Failed;
2627 -- Test if we have more than one interpretation for the context
2630 Resolution_Failed;
2633 -- Only one intepretation
2635 else
2636 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2637 -- the "+" on T is abstract, and the operands are of universal type,
2638 -- the above code will have (incorrectly) resolved the "+" to the
2639 -- universal one in Standard. Therefore check for this case and give
2640 -- an error. We can't do this earlier, because it would cause legal
2641 -- cases to get errors (when some other type has an abstract "+").
2647 then
2652 then
2653 Error_Msg_NE
2662 -- Here we have an acceptable interpretation for the context
2664 -- Propagate type information and normalize tree for various
2665 -- predefined operations. If the context only imposes a class of
2666 -- types, rather than a specific type, propagate the actual type
2667 -- downward.
2673 Typ = Any_Discrete
2674 then
2677 -- Any_Fixed is legal in a real context only if a specific fixed-
2678 -- point type is imposed. If Norman Cohen can be confused by this,
2679 -- it deserves a separate message.
2683 then
2690 -- A user-defined operator is transformed into a function call at
2691 -- this point, so that further processing knows that operators are
2692 -- really operators (i.e. are predefined operators). User-defined
2693 -- operators that are intrinsic are just renamings of the predefined
2694 -- ones, and need not be turned into calls either, but if they rename
2695 -- a different operator, we must transform the node accordingly.
2696 -- Instantiations of Unchecked_Conversion are intrinsic but are
2697 -- treated as functions, even if given an operator designator.
2702 then
2708 and then
2710 N_Subprogram_Renaming_Declaration
2711 then
2714 -- If the node is rewritten, it will be fully resolved in
2715 -- Rewrite_Renamed_Operator.
2725 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2727 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2729 when N_Short_Circuit
2730 => Resolve_Short_Circuit (N, Ctx_Type);
2732 when N_Attribute_Reference
2733 => Resolve_Attribute (N, Ctx_Type);
2735 when N_Case_Expression
2736 => Resolve_Case_Expression (N, Ctx_Type);
2738 when N_Character_Literal
2739 => Resolve_Character_Literal (N, Ctx_Type);
2741 when N_Expanded_Name
2742 => Resolve_Entity_Name (N, Ctx_Type);
2744 when N_Explicit_Dereference
2745 => Resolve_Explicit_Dereference (N, Ctx_Type);
2747 when N_Expression_With_Actions
2748 => Resolve_Expression_With_Actions (N, Ctx_Type);
2750 when N_Extension_Aggregate
2751 => Resolve_Extension_Aggregate (N, Ctx_Type);
2753 when N_Function_Call
2754 => Resolve_Call (N, Ctx_Type);
2756 when N_Identifier
2757 => Resolve_Entity_Name (N, Ctx_Type);
2759 when N_If_Expression
2760 => Resolve_If_Expression (N, Ctx_Type);
2762 when N_Indexed_Component
2763 => Resolve_Indexed_Component (N, Ctx_Type);
2765 when N_Integer_Literal
2766 => Resolve_Integer_Literal (N, Ctx_Type);
2768 when N_Membership_Test
2769 => Resolve_Membership_Op (N, Ctx_Type);
2771 when N_Null => Resolve_Null (N, Ctx_Type);
2773 when N_Op_And | N_Op_Or | N_Op_Xor
2774 => Resolve_Logical_Op (N, Ctx_Type);
2776 when N_Op_Eq | N_Op_Ne
2777 => Resolve_Equality_Op (N, Ctx_Type);
2779 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2780 => Resolve_Comparison_Op (N, Ctx_Type);
2782 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2784 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2785 N_Op_Divide | N_Op_Mod | N_Op_Rem
2787 => Resolve_Arithmetic_Op (N, Ctx_Type);
2789 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2791 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2793 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2794 => Resolve_Unary_Op (N, Ctx_Type);
2796 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2798 when N_Procedure_Call_Statement
2799 => Resolve_Call (N, Ctx_Type);
2801 when N_Operator_Symbol
2802 => Resolve_Operator_Symbol (N, Ctx_Type);
2804 when N_Qualified_Expression
2805 => Resolve_Qualified_Expression (N, Ctx_Type);
2807 when N_Quantified_Expression => null;
2809 when N_Raise_xxx_Error
2810 => Set_Etype (N, Ctx_Type);
2812 when N_Range => Resolve_Range (N, Ctx_Type);
2814 when N_Real_Literal
2815 => Resolve_Real_Literal (N, Ctx_Type);
2817 when N_Reference => Resolve_Reference (N, Ctx_Type);
2819 when N_Selected_Component
2820 => Resolve_Selected_Component (N, Ctx_Type);
2822 when N_Slice => Resolve_Slice (N, Ctx_Type);
2824 when N_String_Literal
2825 => Resolve_String_Literal (N, Ctx_Type);
2827 when N_Subprogram_Info
2828 => Resolve_Subprogram_Info (N, Ctx_Type);
2830 when N_Type_Conversion
2831 => Resolve_Type_Conversion (N, Ctx_Type);
2833 when N_Unchecked_Expression =>
2834 Resolve_Unchecked_Expression (N, Ctx_Type);
2836 when N_Unchecked_Type_Conversion =>
2837 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2838 end case;
2840 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2841 -- expression of an anonymous access type that occurs in the context
2842 -- of a named general access type, except when the expression is that
2843 -- of a membership test. This ensures proper legality checking in
2844 -- terms of allowed conversions (expressions that would be illegal to
2845 -- convert implicitly are allowed in membership tests).
2847 if Ada_Version >= Ada_2012
2848 and then Ekind (Ctx_Type) = E_General_Access_Type
2849 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2850 and then Nkind (Parent (N)) not in N_Membership_Test
2851 then
2852 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2853 Analyze_And_Resolve (N, Ctx_Type);
2854 end if;
2856 -- If the subexpression was replaced by a non-subexpression, then
2857 -- all we do is to expand it. The only legitimate case we know of
2858 -- is converting procedure call statement to entry call statements,
2859 -- but there may be others, so we are making this test general.
2861 if Nkind (N) not in N_Subexpr then
2862 Debug_A_Exit ("resolving ", N, " (done)");
2863 Expand (N);
2864 return;
2865 end if;
2867 -- The expression is definitely NOT overloaded at this point, so
2868 -- we reset the Is_Overloaded flag to avoid any confusion when
2869 -- reanalyzing the node.
2871 Set_Is_Overloaded (N, False);
2873 -- Freeze expression type, entity if it is a name, and designated
2874 -- type if it is an allocator (RM 13.14(10,11,13)).
2876 -- Now that the resolution of the type of the node is complete, and
2877 -- we did not detect an error, we can expand this node. We skip the
2878 -- expand call if we are in a default expression, see section
2879 -- "Handling of Default Expressions" in Sem spec.
2881 Debug_A_Exit ("resolving ", N, " (done)");
2883 -- We unconditionally freeze the expression, even if we are in
2884 -- default expression mode (the Freeze_Expression routine tests this
2885 -- flag and only freezes static types if it is set).
2887 -- Ada 2012 (AI05-177): Expression functions do not freeze. Only
2888 -- their use (in an expanded call) freezes.
2890 if Ekind (Proper_Current_Scope) /= E_Function
2891 or else Nkind (Original_Node (Unit_Declaration_Node
2892 (Proper_Current_Scope))) /= N_Expression_Function
2893 then
2894 Freeze_Expression (N);
2895 end if;
2897 -- Now we can do the expansion
2899 Expand (N);
2900 end if;
2901 end Resolve;
2903 -------------
2904 -- Resolve --
2905 -------------
2907 -- Version with check(s) suppressed
2909 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2910 begin
2911 if Suppress = All_Checks then
2912 declare
2913 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
2914 begin
2915 Scope_Suppress.Suppress := (others => True);
2916 Resolve (N, Typ);
2917 Scope_Suppress.Suppress := Sva;
2918 end;
2920 else
2921 declare
2922 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
2923 begin
2924 Scope_Suppress.Suppress (Suppress) := True;
2925 Resolve (N, Typ);
2926 Scope_Suppress.Suppress (Suppress) := Svg;
2927 end;
2928 end if;
2929 end Resolve;
2931 -------------
2932 -- Resolve --
2933 -------------
2935 -- Version with implicit type
2937 procedure Resolve (N : Node_Id) is
2938 begin
2939 Resolve (N, Etype (N));
2940 end Resolve;
2942 ---------------------
2943 -- Resolve_Actuals --
2944 ---------------------
2946 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2947 Loc : constant Source_Ptr := Sloc (N);
2948 A : Node_Id;
2949 F : Entity_Id;
2950 A_Typ : Entity_Id;
2951 F_Typ : Entity_Id;
2952 Prev : Node_Id := Empty;
2953 Orig_A : Node_Id;
2955 procedure Check_Argument_Order;
2956 -- Performs a check for the case where the actuals are all simple
2957 -- identifiers that correspond to the formal names, but in the wrong
2958 -- order, which is considered suspicious and cause for a warning.
2960 procedure Check_Prefixed_Call;
2961 -- If the original node is an overloaded call in prefix notation,
2963 -- Try_Object_Operation has already verified that there is a valid
2964 -- interpretation, but the form of the actual can only be determined
2965 -- once the primitive operation is identified.
2968 -- If the actual is missing in a call, insert in the actuals list
2969 -- an instance of the default expression. The insertion is always
2970 -- a named association.
2973 -- Check whether T1 and T2, or their full views, are derived from a
2974 -- common type. Used to enforce the restrictions on array conversions
2975 -- of AI95-00246.
2978 -- Predicate to determine whether an actual that is a concatenation
2979 -- will be evaluated statically and does not need a transient scope.
2980 -- This must be determined before the actual is resolved and expanded
2981 -- because if needed the transient scope must be introduced earlier.
2983 --------------------------
2984 -- Check_Argument_Order --
2985 --------------------------
2988 begin
2989 -- Nothing to do if no parameters, or original node is neither a
2990 -- function call nor a procedure call statement (happens in the
2991 -- operator-transformed-to-function call case), or the call does
2992 -- not come from source, or this warning is off.
2994 if not Warn_On_Parameter_Order
2998 then
3002 declare
3005 begin
3006 -- Nothing to do if only one parameter
3012 -- Here if at least two arguments
3014 declare
3020 -- Set True if an out of order case is found
3022 begin
3023 -- Collect identifier names of actuals, fail if any actual is
3024 -- not a simple identifier, and record max length of name.
3030 else
3036 -- If we got this far, all actuals are identifiers and the list
3037 -- of their names is stored in the Actuals array.
3042 -- If we ran out of formals, that's odd, probably an error
3043 -- which will be detected elsewhere, but abandon the search.
3049 -- If name matches and is in order OK
3054 else
3055 -- If no match, see if it is elsewhere in list and if so
3056 -- flag potential wrong order if type is compatible.
3060 and then
3062 then
3068 -- No match
3076 -- If Formals left over, also probably an error, skip warning
3082 -- Here we give the warning if something was out of order
3085 Error_Msg_N
3092 -------------------------
3093 -- Check_Prefixed_Call --
3094 -------------------------
3103 begin
3104 -- Check whether the call is a prefixed call, with or without
3105 -- additional actuals.
3108 or else
3114 then
3117 then
3118 -- Introduce dereference on object in prefix
3120 New_A :=
3128 then
3129 -- Introduce an implicit 'Access in prefix
3132 Error_Msg_NE
3148 --------------------
3149 -- Insert_Default --
3150 --------------------
3156 begin
3157 -- Missing argument in call, nothing to insert
3162 else
3163 -- Note that we do a full New_Copy_Tree, so that any associated
3164 -- Itypes are properly copied. This may not be needed any more,
3165 -- but it does no harm as a safety measure! Defaults of a generic
3166 -- formal may be out of bounds of the corresponding actual (see
3167 -- cc1311b) and an additional check may be required.
3169 Actval :=
3170 New_Copy_Tree
3177 then
3183 then
3186 then
3187 -- If default is a real literal, do not introduce a
3188 -- conversion whose effect may depend on the run-time
3189 -- size of universal real.
3193 else
3204 -- Resolve aggregates with their base type, to avoid scope
3205 -- anomalies: the subtype was first built in the subprogram
3206 -- declaration, and the current call may be nested.
3210 else
3214 else
3217 -- See note above concerning aggregates
3221 then
3224 -- Resolve entities with their own type, which may differ from
3225 -- the type of a reference in a generic context (the view
3226 -- swapping mechanism did not anticipate the re-analysis of
3227 -- default values in calls).
3232 else
3237 -- If default is a tag indeterminate function call, propagate tag
3238 -- to obtain proper dispatching.
3242 then
3248 -- If the default expression raises constraint error, then just
3249 -- silently replace it with an N_Raise_Constraint_Error node, since
3250 -- we already gave the warning on the subprogram spec. If node is
3251 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3252 -- the warnings removal machinery.
3256 then
3264 Assoc :=
3269 -- Case of insertion is first named actual
3273 then
3280 else
3284 else
3288 -- Case of insertion is not first named actual
3290 else
3291 Set_Next_Named_Actual
3303 -------------------
3304 -- Same_Ancestor --
3305 -------------------
3311 begin
3314 then
3320 then
3327 --------------------------
3328 -- Static_Concatenation --
3329 --------------------------
3332 begin
3339 -- Concatenation is static when both operands are static and
3340 -- the concatenation operator is a predefined one.
3343 and then
3345 and then
3350 declare
3352 begin
3355 and then
3359 else
3365 -- Start of processing for Resolve_Actuals
3367 begin
3368 Check_Argument_Order;
3372 Check_Prefixed_Call;
3381 -- If we have an error in any actual or formal, indicated by a type
3382 -- of Any_Type, then abandon resolution attempt, and set result type
3383 -- to Any_Type.
3387 then
3392 -- Case where actual is present
3394 -- If the actual is an entity, generate a reference to it now. We
3395 -- do this before the actual is resolved, because a formal of some
3396 -- protected subprogram, or a task discriminant, will be rewritten
3397 -- during expansion, and the source entity reference may be lost.
3402 then
3408 then
3415 -- RM 6.4.1(12): For an out parameter that is passed by
3416 -- copy, the formal parameter object is created, and:
3418 -- * For an access type, the formal parameter is initialized
3419 -- from the value of the actual, without checking that the
3420 -- value satisfies any constraint, any predicate, or any
3421 -- exclusion of the null value.
3423 -- * For a scalar type that has the Default_Value aspect
3424 -- specified, the formal parameter is initialized from the
3425 -- value of the actual, without checking that the value
3426 -- satisfies any constraint or any predicate.
3427 -- I do not understand why this case is included??? this is
3428 -- not a case where an OUT parameter is treated as IN OUT.
3430 -- * For a composite type with discriminants or that has
3431 -- implicit initial values for any subcomponents, the
3432 -- behavior is as for an in out parameter passed by copy.
3434 -- Hence for these cases we generate the read reference now
3435 -- (the write reference will be generated later by
3436 -- Note_Possible_Modification).
3439 and then
3441 or else
3443 and then
3445 or else
3448 or else Is_Partially_Initialized_Type
3450 then
3460 then
3461 -- If style checking mode on, check match of formal name
3469 -- If the formal is Out or In_Out, do not resolve and expand the
3470 -- conversion, because it is subsequently expanded into explicit
3471 -- temporaries and assignments. However, the object of the
3472 -- conversion can be resolved. An exception is the case of tagged
3473 -- type conversion with a class-wide actual. In that case we want
3474 -- the tag check to occur and no temporary will be needed (no
3475 -- representation change can occur) and the parameter is passed by
3476 -- reference, so we go ahead and resolve the type conversion.
3477 -- Another exception is the case of reference to component or
3478 -- subcomponent of a bit-packed array, in which case we want to
3479 -- defer expansion to the point the in and out assignments are
3480 -- performed.
3485 then
3488 then
3489 -- In a view conversion, the conversion must be legal in
3490 -- both directions, and thus both component types must be
3491 -- aliased, or neither (4.6 (8)).
3493 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3494 -- the privacy requirement should not apply to generic
3495 -- types, and should be checked in an instance. ARG query
3496 -- is in order ???
3500 then
3501 Error_Msg_N
3505 -- Comment here??? what set of cases???
3507 elsif
3509 then
3510 -- Check view conv between unrelated by ref array types
3514 then
3515 Error_Msg_N
3519 -- In Ada 2005 mode, check view conversion component
3520 -- type cannot be private, tagged, or volatile. Note
3521 -- that we only apply this to source conversions. The
3522 -- generated code can contain conversions which are
3523 -- not subject to this test, and we cannot extract the
3524 -- component type in such cases since it is not present.
3528 then
3529 declare
3531 Component_Type
3533 begin
3538 then
3539 Error_Msg_N
3550 -- Resolve expression if conversion is all OK
3555 then
3559 -- If the actual is a function call that returns a limited
3560 -- unconstrained object that needs finalization, create a
3561 -- transient scope for it, so that it can receive the proper
3562 -- finalization list.
3567 and then Full_Expander_Active
3569 then
3573 -- A small optimization: if one of the actuals is a concatenation
3574 -- create a block around a procedure call to recover stack space.
3575 -- This alleviates stack usage when several procedure calls in
3576 -- the same statement list use concatenation. We do not perform
3577 -- this wrapping for code statements, where the argument is a
3578 -- static string, and we want to preserve warnings involving
3579 -- sequences of such statements.
3583 and then Full_Expander_Active
3584 and then
3588 then
3592 else
3596 and then
3599 then
3600 Error_Msg_N
3613 -- (Ada 2005: AI-251): If the actual is an allocator whose
3614 -- directly designated type is a class-wide interface, we build
3615 -- an anonymous access type to use it as the type of the
3616 -- allocator. Later, when the subprogram call is expanded, if
3617 -- the interface has a secondary dispatch table the expander
3618 -- will add a type conversion to force the correct displacement
3619 -- of the pointer.
3622 declare
3628 begin
3631 then
3639 -- Ada 2005, AI-162:If the actual is an allocator, the
3640 -- innermost enclosing statement is the master of the
3641 -- created object. This needs to be done with expansion
3642 -- enabled only, otherwise the transient scope will not
3643 -- be removed in the expansion of the wrapped construct.
3646 and then Full_Expander_Active
3647 then
3653 -- (Ada 2005): The call may be to a primitive operation of
3654 -- a tagged synchronized type, declared outside of the type.
3655 -- In this case the controlling actual must be converted to
3656 -- its corresponding record type, which is the formal type.
3657 -- The actual may be a subtype, either because of a constraint
3658 -- or because it is a generic actual, so use base type to
3659 -- locate concurrent type.
3666 then
3667 -- If the actual is overloaded, look for an interpretation
3668 -- that has a synchronized type.
3673 else
3674 declare
3678 begin
3683 then
3693 declare
3696 begin
3699 else
3703 -- Tagged synchronized type (case 1): the actual is a
3704 -- concurrent type.
3708 then
3710 Unchecked_Convert_To
3714 -- Tagged synchronized type (case 2): the formal is a
3715 -- concurrent type.
3718 and then Present
3723 then
3726 -- Common case
3728 else
3732 else
3734 -- not a synchronized operation.
3745 N_Procedure_Call_Statement)
3746 then
3747 -- In formal mode, check that actual parameters matching
3748 -- formals of tagged types are objects (or ancestor type
3749 -- conversions of objects), not general expressions.
3756 declare
3761 begin
3763 Check_SPARK_Restriction
3766 -- In formal mode, the only view conversions are those
3767 -- involving ancestor conversion of an extended type.
3769 elsif not
3775 then
3776 if Ekind_In
3778 then
3779 Check_SPARK_Restriction
3782 else
3783 Check_SPARK_Restriction
3787 else
3792 else
3796 -- In formal mode, the only view conversions are those
3797 -- involving ancestor conversion of an extended type.
3801 then
3802 Check_SPARK_Restriction
3808 -- has warnings suppressed, then we reset Never_Set_In_Source for
3809 -- the calling entity. The reason for this is to catch cases like
3810 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3811 -- uses trickery to modify an IN parameter.
3818 then
3822 -- Perform error checks for IN and IN OUT parameters
3826 -- Check unset reference. For scalar parameters, it is clearly
3827 -- wrong to pass an uninitialized value as either an IN or
3828 -- IN-OUT parameter. For composites, it is also clearly an
3829 -- error to pass a completely uninitialized value as an IN
3830 -- parameter, but the case of IN OUT is trickier. We prefer
3831 -- not to give a warning here. For example, suppose there is
3832 -- a routine that sets some component of a record to False.
3833 -- It is perfectly reasonable to make this IN-OUT and allow
3834 -- either initialized or uninitialized records to be passed
3835 -- in this case.
3837 -- For partially initialized composite values, we also avoid
3838 -- warnings, since it is quite likely that we are passing a
3839 -- partially initialized value and only the initialized fields
3840 -- will in fact be read in the subprogram.
3845 then
3849 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3850 -- actual to a nested call, since this is case of reading an
3851 -- out parameter, which is not allowed.
3856 then
3861 -- Case of OUT or IN OUT parameter
3865 -- For an Out parameter, check for useless assignment. Note
3866 -- that we can't set Last_Assignment this early, because we may
3867 -- kill current values in Resolve_Call, and that call would
3868 -- clobber the Last_Assignment field.
3870 -- Note: call Warn_On_Useless_Assignment before doing the check
3871 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3872 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3873 -- reflects the last assignment, not this one!
3880 then
3885 -- Validate the form of the actual. Note that the call to
3886 -- Is_OK_Variable_For_Out_Formal generates the required
3887 -- reference in this case.
3889 -- A call to an initialization procedure for an aggregate
3890 -- component may initialize a nested component of a constant
3891 -- designated object. In this context the object is variable.
3895 then
3899 -- What's the following about???
3903 else
3904 Kill_All_Checks;
3913 -- Apply appropriate range checks for in, out, and in-out
3914 -- parameters. Out and in-out parameters also need a separate
3915 -- check, if there is a type conversion, to make sure the return
3916 -- value meets the constraints of the variable before the
3917 -- conversion.
3919 -- Gigi looks at the check flag and uses the appropriate types.
3920 -- For now since one flag is used there is an optimization which
3921 -- might not be done in the In Out case since Gigi does not do
3922 -- any analysis. More thought required about this ???
3926 -- Apply predicate checks, unless this is a call to the
3927 -- predicate check function itself, which would cause an
3928 -- infinite recursion.
3932 then
3936 -- Apply required constraint checks
3949 then
3955 then
3961 then
3964 else
3968 -- Ada 2005 (AI-231): Note that the controlling parameter case
3969 -- already existed in Ada 95, which is partially checked
3970 -- elsewhere (see Checks), and we don't want the warning
3971 -- message to differ.
3976 then
3978 Apply_Compile_Time_Constraint_Error
3984 Apply_Compile_Time_Constraint_Error
3996 Apply_Scalar_Range_Check
3998 else
3999 Apply_Range_Check
4003 else
4008 then
4010 else
4016 -- An actual associated with an access parameter is implicitly
4017 -- converted to the anonymous access type of the formal and must
4018 -- satisfy the legality checks for access conversions.
4022 Error_Msg_N
4026 -- If the actual is an access selected component of a variable,
4027 -- the call may modify its designated object. It is reasonable
4028 -- to treat this as a potential modification of the enclosing
4029 -- record, to prevent spurious warnings that it should be
4030 -- declared as a constant, because intuitively programmers
4031 -- regard the designated subcomponent as part of the record.
4036 then
4041 -- Check bad case of atomic/volatile argument (RM C.6(12))
4045 then
4048 then
4049 Error_Msg_NE
4055 then
4056 Error_Msg_NE
4062 -- Check that subprograms don't have improper controlling
4063 -- arguments (RM 3.9.2 (9)).
4065 -- A primitive operation may have an access parameter of an
4066 -- incomplete tagged type, but a dispatching call is illegal
4067 -- if the type is still incomplete.
4073 declare
4075 begin
4079 then
4080 Error_Msg_NE
4094 then
4099 then
4101 Error_Msg_NE
4105 -- Apply the checks described in 3.10.2(27): if the context is a
4106 -- specific access-to-object, the actual cannot be class-wide.
4107 -- Use base type to exclude access_to_subprogram cases.
4114 and then
4119 -- Disable these checks for call to imported C++ subprograms
4121 and then not
4125 then
4126 Error_Msg_N
4131 Error_Msg_NE
4138 -- If it is a named association, treat the selector_name as a
4139 -- proper identifier, and mark the corresponding entity. Ignore
4140 -- this reference in Alfa mode, as it refers to an entity not in
4141 -- scope at the point of reference, so the reference should be
4142 -- ignored for computing effects of subprograms.
4145 and then not Alfa_Mode
4146 then
4161 -- Case where actual is not present
4163 else
4164 Insert_Default;
4171 -----------------------
4172 -- Resolve_Allocator --
4173 -----------------------
4185 procedure Check_Allocator_Discrim_Accessibility
4188 -- Check that accessibility level associated with an access discriminant
4189 -- initialized in an allocator by the expression Disc_Exp is not deeper
4190 -- than the level of the allocator type Alloc_Typ. An error message is
4191 -- issued if this condition is violated. Specialized checks are done for
4192 -- the cases of a constraint expression which is an access attribute or
4193 -- an access discriminant.
4196 -- If the allocator is an actual in a call, it is allowed to be class-
4197 -- wide when the context is not because it is a controlling actual.
4199 -------------------------------------------
4200 -- Check_Allocator_Discrim_Accessibility --
4201 -------------------------------------------
4203 procedure Check_Allocator_Discrim_Accessibility
4206 is
4207 begin
4210 then
4211 Error_Msg_N
4214 -- When the expression is an Access attribute the level of the prefix
4215 -- object must not be deeper than that of the allocator's type.
4219 Attribute_Access
4222 then
4223 Error_Msg_N
4225 Disc_Exp);
4227 -- When the expression is an access discriminant the check is against
4228 -- the level of the prefix object.
4234 then
4235 Error_Msg_N
4237 Disc_Exp);
4239 -- All other cases are legal
4241 else
4246 ----------------------------
4247 -- In_Dispatching_Context --
4248 ----------------------------
4253 begin
4259 -- Start of processing for Resolve_Allocator
4261 begin
4262 -- Replace general access with specific type
4272 -- For qualified expression, resolve the expression using the
4273 -- given subtype (nothing to do for type mark, subtype indication)
4278 and then not In_Dispatching_Context
4279 then
4280 Error_Msg_N
4287 -- A qualified expression requires an exact match of the type,
4288 -- class-wide matching is not allowed.
4293 then
4297 -- Calls to build-in-place functions are not currently supported in
4298 -- allocators for access types associated with a simple storage pool.
4299 -- Supporting such allocators may require passing additional implicit
4300 -- parameters to build-in-place functions (or a significant revision
4301 -- of the current b-i-p implementation to unify the handling for
4302 -- multiple kinds of storage pools). ???
4306 then
4307 declare
4310 begin
4312 and then
4313 Present (Get_Rep_Pragma
4315 then
4316 Error_Msg_N
4323 -- A special accessibility check is needed for allocators that
4324 -- constrain access discriminants. The level of the type of the
4325 -- expression used to constrain an access discriminant cannot be
4326 -- deeper than the type of the allocator (in contrast to access
4327 -- parameters, where the level of the actual can be arbitrary).
4329 -- We can't use Valid_Conversion to perform this check because
4330 -- in general the type of the allocator is unrelated to the type
4331 -- of the access discriminant.
4335 then
4342 then
4345 -- Get the first component expression of the aggregate
4355 else
4359 else
4378 else
4383 else
4392 -- For a subtype mark or subtype indication, freeze the subtype
4394 else
4398 Error_Msg_N
4402 -- A special accessibility check is needed for allocators that
4403 -- constrain access discriminants. The level of the type of the
4404 -- expression used to constrain an access discriminant cannot be
4405 -- deeper than the type of the allocator (in contrast to access
4406 -- parameters, where the level of the actual can be arbitrary).
4407 -- We can't use Valid_Conversion to perform this check because
4408 -- in general the type of the allocator is unrelated to the type
4409 -- of the access discriminant.
4414 then
4424 else
4438 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4439 -- check that the level of the type of the created object is not deeper
4440 -- than the level of the allocator's access type, since extensions can
4441 -- now occur at deeper levels than their ancestor types. This is a
4442 -- static accessibility level check; a run-time check is also needed in
4443 -- the case of an initialized allocator with a class-wide argument (see
4444 -- Expand_Allocator_Expression).
4448 then
4449 declare
4452 begin
4457 else
4463 then
4468 E);
4474 -- Do not apply Ada 2005 accessibility checks on a class-wide
4475 -- allocator if the type given in the allocator is a formal
4476 -- type. A run-time check will be performed in the instance.
4486 -- Check for allocation from an empty storage pool
4491 -- If the context is an unchecked conversion, as may happen within an
4492 -- inlined subprogram, the allocator is being resolved with its own
4493 -- anonymous type. In that case, if the target type has a specific
4494 -- storage pool, it must be inherited explicitly by the allocator type.
4498 then
4499 Set_Associated_Storage_Pool
4507 -- Check that an allocator with task parts isn't for a nested access
4508 -- type when restriction No_Task_Hierarchy applies.
4512 then
4516 -- An erroneous allocator may be rewritten as a raise Program_Error
4517 -- statement.
4521 -- An anonymous access discriminant is the definition of a
4522 -- coextension.
4526 N_Discriminant_Specification
4527 then
4528 declare
4532 begin
4533 -- Ada 2012 AI05-0052: If the designated type of the allocator
4534 -- is limited, then the allocator shall not be used to define
4535 -- the value of an access discriminant unless the discriminated
4536 -- type is immutably limited.
4541 then
4542 Error_Msg_N
4548 -- Avoid marking an allocator as a dynamic coextension if it is
4549 -- within a static construct.
4555 -- Cleanup for potential static coextensions
4557 else
4563 -- Report a simple error: if the designated object is a local task,
4564 -- its body has not been seen yet, and its activation will fail an
4565 -- elaboration check.
4572 then
4577 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4578 -- type with a task component on a subpool. This action must raise
4579 -- Program_Error at runtime.
4585 then
4596 ---------------------------
4597 -- Resolve_Arithmetic_Op --
4598 ---------------------------
4600 -- Used for resolving all arithmetic operators except exponentiation
4611 -- We do the resolution using the base type, because intermediate values
4612 -- in expressions always are of the base type, not a subtype of it.
4615 -- Returns True if N is in a context that expects "any real type"
4618 -- Return True iff given type is Integer or universal real/integer
4621 -- Choose type of integer literal in fixed-point operation to conform
4622 -- to available fixed-point type. T is the type of the other operand,
4623 -- which is needed to determine the expected type of N.
4626 -- Set operand type to T if universal
4628 -------------------------------
4629 -- Expected_Type_Is_Any_Real --
4630 -------------------------------
4633 begin
4634 -- N is the expression after "delta" in a fixed_point_definition;
4635 -- see RM-3.5.9(6):
4638 N_Decimal_Fixed_Point_Definition,
4640 -- N is one of the bounds in a real_range_specification;
4641 -- see RM-3.5.7(5):
4643 N_Real_Range_Specification,
4645 -- N is the expression of a delta_constraint;
4646 -- see RM-J.3(3):
4648 N_Delta_Constraint);
4651 -----------------------------
4652 -- Is_Integer_Or_Universal --
4653 -----------------------------
4660 begin
4666 else
4672 then
4683 ----------------------------
4684 -- Set_Mixed_Mode_Operand --
4685 ----------------------------
4691 begin
4694 -- A universal integer literal is resolved as standard integer
4695 -- except in the case of a fixed-point result, where we leave it
4696 -- as universal (to be handled by Exp_Fixd later on)
4700 else
4708 then
4709 -- A universal real can appear in a fixed-type context. We resolve
4710 -- the literal with that context, even though this might raise an
4711 -- exception prematurely (the other operand may be zero).
4718 then
4719 -- Integer arg in mixed-mode operation. Resolve with universal
4720 -- type, in case preference rule must be applied.
4726 then
4727 -- Not a mixed-mode operation, resolve with context
4733 -- N may itself be a mixed-mode operation, so use context type
4740 then
4741 -- Must be (fixed * fixed) operation, operand must have one
4742 -- compatible interpretation.
4750 then
4751 -- C * F(X) in a fixed context, where C is a real literal or a
4752 -- fixed-point expression. F must have either a fixed type
4753 -- interpretation or an integer interpretation, but not both.
4760 else
4767 else
4775 -- Reanalyze the literal with the fixed type of the context. If
4776 -- context is Universal_Fixed, we are within a conversion, leave
4777 -- the literal as a universal real because there is no usable
4778 -- fixed type, and the target of the conversion plays no role in
4779 -- the resolution.
4781 declare
4785 begin
4788 else
4794 then
4796 else
4804 else
4809 ----------------------
4810 -- Set_Operand_Type --
4811 ----------------------
4814 begin
4817 then
4822 -- Start of processing for Resolve_Arithmetic_Op
4824 begin
4829 then
4833 -- Special-case for mixed-mode universal expressions or fixed point type
4834 -- operation: each argument is resolved separately. The same treatment
4835 -- is required if one of the operands of a fixed point operation is
4836 -- universal real, since in this case we don't do a conversion to a
4837 -- specific fixed-point type (instead the expander handles the case).
4839 -- Set the type of the node to its universal interpretation because
4840 -- legality checks on an exponentiation operand need the context.
4845 then
4856 or else
4859 then
4864 -- If context is a fixed type and one operand is integer, the other
4865 -- is resolved with the type of the context.
4870 then
4877 then
4881 else
4886 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4887 -- multiplying operators from being used when the expected type is
4888 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4889 -- some cases where the expected type is actually Any_Real;
4890 -- Expected_Type_Is_Any_Real takes care of that case.
4894 then
4898 N_Unchecked_Type_Conversion)
4899 then
4906 else
4909 and then not
4911 N_Unchecked_Type_Conversion)
4912 then
4913 Error_Msg_N
4918 -- The expected type is "any real type" in contexts like
4920 -- type T is delta <universal_fixed-expression> ...
4922 -- in which case we need to set the type to Universal_Real
4923 -- so that static expression evaluation will work properly.
4927 else
4937 then
4942 -- If no previous errors, this is only possible if one operand is
4943 -- overloaded and the context is universal. Resolve as such.
4948 else
4950 and then
4952 then
4956 -- If the context is Universal_Fixed and the operands are also
4957 -- universal fixed, this is an error, unless there is only one
4958 -- applicable fixed_point type (usually Duration).
4966 else
4971 else
4976 -- If one of the arguments was resolved to a non-universal type.
4977 -- label the result of the operation itself with the same type.
4978 -- Do the same for the universal argument, if any.
4990 -- In SPARK, a multiplication or division with operands of fixed point
4991 -- types shall be qualified or explicitly converted to identify the
4992 -- result type.
4997 and then
4999 then
5000 Check_SPARK_Restriction
5004 -- Set overflow and division checking bit
5011 -- Give warning if explicit division by zero
5015 then
5021 or else
5024 then
5025 -- Specialize the warning message according to the operation.
5026 -- The following warnings are for the case
5031 -- For division, we have two cases, for float division
5032 -- of an unconstrained float type, on a machine where
5033 -- Machine_Overflows is false, we don't get an exception
5034 -- at run-time, but rather an infinity or Nan. The Nan
5035 -- case is pretty obscure, so just warn about infinities.
5039 and then not Machine_Overflows_On_Target
5040 then
5041 Error_Msg_N
5045 -- For all other cases, we get a Constraint_Error
5047 else
5048 Apply_Compile_Time_Constraint_Error
5054 Apply_Compile_Time_Constraint_Error
5059 Apply_Compile_Time_Constraint_Error
5063 -- Division by zero can only happen with division, rem,
5064 -- and mod operations.
5070 -- Otherwise just set the flag to check at run time
5072 else
5077 -- If Restriction No_Implicit_Conditionals is active, then it is
5078 -- violated if either operand can be negative for mod, or for rem
5079 -- if both operands can be negative.
5083 then
5084 declare
5091 -- Set if corresponding operand might be negative
5093 begin
5094 Determine_Range
5098 Determine_Range
5102 -- Check if we will be generating conditionals. There are two
5103 -- cases where that can happen, first for REM, the only case
5104 -- is largest negative integer mod -1, where the division can
5105 -- overflow, but we still have to give the right result. The
5106 -- front end generates a test for this annoying case. Here we
5107 -- just test if both operands can be negative (that's what the
5108 -- expander does, so we match its logic here).
5110 -- The second case is mod where either operand can be negative.
5111 -- In this case, the back end has to generate additional tests.
5114 or else
5116 then
5128 ------------------
5129 -- Resolve_Call --
5130 ------------------
5142 function Same_Or_Aliased_Subprograms
5145 -- Returns True if the subprogram entity S is the same as E or else
5146 -- S is an alias of E.
5148 ---------------------------------
5149 -- Same_Or_Aliased_Subprograms --
5150 ---------------------------------
5152 function Same_Or_Aliased_Subprograms
5155 is
5157 begin
5162 -- Start of processing for Resolve_Call
5164 begin
5165 -- The context imposes a unique interpretation with type Typ on a
5166 -- procedure or function call. Find the entity of the subprogram that
5167 -- yields the expected type, and propagate the corresponding formal
5168 -- constraints on the actuals. The caller has established that an
5169 -- interpretation exists, and emitted an error if not unique.
5171 -- First deal with the case of a call to an access-to-subprogram,
5172 -- dereference made explicit in Analyze_Call.
5178 else
5179 -- Find the interpretation whose type (a subprogram type) has a
5180 -- return type that is compatible with the context. Analysis of
5181 -- the node has established that one exists.
5200 -- If the prefix is not an entity, then resolve it
5206 -- For an indirect call, we always invalidate checks, since we do not
5207 -- know whether the subprogram is local or global. Yes we could do
5208 -- better here, e.g. by knowing that there are no local subprograms,
5209 -- but it does not seem worth the effort. Similarly, we kill all
5210 -- knowledge of current constant values.
5212 Kill_Current_Values;
5214 -- If this is a procedure call which is really an entry call, do
5215 -- the conversion of the procedure call to an entry call. Protected
5216 -- operations use the same circuitry because the name in the call
5217 -- can be an arbitrary expression with special resolution rules.
5222 then
5226 -- Kill checks and constant values, as above for indirect case
5227 -- Who knows what happens when another task is activated?
5229 Kill_Current_Values;
5232 -- Normal subprogram call with name established in Resolve
5238 -- Otherwise we must have the case of an overloaded call
5240 else
5243 -- Initialize Nam to prevent warning (we know it will be assigned
5244 -- in the loop below, but the compiler does not know that).
5264 then
5265 -- The prefix is a parameterless function call that returns an access
5266 -- to subprogram. If parameters are present in the current call, add
5267 -- add an explicit dereference. We use the base type here because
5268 -- within an instance these may be subtypes.
5270 -- The dereference is added either in Analyze_Call or here. Should
5271 -- be consolidated ???
5280 -- Check that a call to Current_Task does not occur in an entry body
5283 declare
5286 begin
5288 loop
5291 -- Exclude calls that occur within the default of a formal
5292 -- parameter of the entry, since those are evaluated outside
5293 -- of the body.
5300 then
5302 Error_Msg_NE
5305 Error_Msg_NE
5317 -- Check that a procedure call does not occur in the context of the
5318 -- entry call statement of a conditional or timed entry call. Note that
5319 -- the case of a call to a subprogram renaming of an entry will also be
5320 -- rejected. The test for N not being an N_Entry_Call_Statement is
5321 -- defensive, covering the possibility that the processing of entry
5322 -- calls might reach this point due to later modifications of the code
5323 -- above.
5328 then
5332 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5333 -- for a procedure_or_entry_call, the procedure_name or
5334 -- procedure_prefix of the procedure_call_statement shall denote
5335 -- an entry renamed by a procedure, or (a view of) a primitive
5336 -- subprogram of a limited interface whose first parameter is
5337 -- a controlling parameter.
5342 then
5343 Error_Msg_N
5348 -- Check that this is not a call to a protected procedure or entry from
5349 -- within a protected function.
5353 -- Freeze the subprogram name if not in a spec-expression. Note that we
5354 -- freeze procedure calls as well as function calls. Procedure calls are
5355 -- not frozen according to the rules (RM 13.14(14)) because it is
5356 -- impossible to have a procedure call to a non-frozen procedure in pure
5357 -- Ada, but in the code that we generate in the expander, this rule
5358 -- needs extending because we can generate procedure calls that need
5359 -- freezing.
5361 -- In Ada 2012, expression functions may be called within pre/post
5362 -- conditions of subsequent functions or expression functions. Such
5363 -- calls do not freeze when they appear within generated bodies, which
5364 -- would place the freeze node in the wrong scope. An expression
5365 -- function is frozen in the usual fashion, by the appearance of a real
5366 -- body, or at the end of a declarative part.
5369 and then
5372 then
5376 -- For a predefined operator, the type of the result is the type imposed
5377 -- by context, except for a predefined operation on universal fixed.
5378 -- Otherwise The type of the call is the type returned by the subprogram
5379 -- being called.
5386 -- If the subprogram returns an array type, and the context requires the
5387 -- component type of that array type, the node is really an indexing of
5388 -- the parameterless call. Resolve as such. A pathological case occurs
5389 -- when the type of the component is an access to the array type. In
5390 -- this case the call is truly ambiguous.
5393 and then
5398 and then
5399 Covers
5402 then
5403 declare
5408 begin
5411 then
5412 Error_Msg_N
5414 else
5420 or else
5422 and then
5424 then
5427 -- Indexed call to a parameterless function
5429 Index_Node :=
5431 Prefix =>
5435 else
5436 -- An Ada 2005 prefixed call to a primitive operation
5437 -- whose first parameter is the prefix. This prefix was
5438 -- prepended to the parameter list, which is actually a
5439 -- list of indexes. Remove the prefix in order to build
5440 -- the proper indexed component.
5442 Index_Node :=
5444 Prefix =>
5447 Parameter_Associations =>
5448 New_List
5453 -- Preserve the parenthesis count of the node
5457 -- Since we are correcting a node classification error made
5458 -- by the parser, we call Replace rather than Rewrite.
5472 else
5476 -- In the case where the call is to an overloaded subprogram, Analyze
5477 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5478 -- such a case Normalize_Actuals needs to be called once more to order
5479 -- the actuals correctly. Otherwise the call will have the ordering
5480 -- given by the last overloaded subprogram whether this is the correct
5481 -- one being called or not.
5488 -- In any case, call is fully resolved now. Reset Overload flag, to
5489 -- prevent subsequent overload resolution if node is analyzed again
5494 -- If we are calling the current subprogram from immediately within its
5495 -- body, then that is the case where we can sometimes detect cases of
5496 -- infinite recursion statically. Do not try this in case restriction
5497 -- No_Recursion is in effect anyway, and do it only for source calls.
5502 -- Issue warning for possible infinite recursion in the absence
5503 -- of the No_Recursion restriction.
5508 then
5509 -- Here we detected and flagged an infinite recursion, so we do
5510 -- not need to test the case below for further warnings. Also we
5511 -- are all done if we now have a raise SE node.
5517 -- If call is to immediately containing subprogram, then check for
5518 -- the case of a possible run-time detectable infinite recursion.
5520 else
5524 -- Although in general case, recursion is not statically
5525 -- checkable, the case of calling an immediately containing
5526 -- subprogram is easy to catch.
5530 -- If the recursive call is to a parameterless subprogram,
5531 -- then even if we can't statically detect infinite
5532 -- recursion, this is pretty suspicious, and we output a
5533 -- warning. Furthermore, we will try later to detect some
5534 -- cases here at run time by expanding checking code (see
5535 -- Detect_Infinite_Recursion in package Exp_Ch6).
5537 -- If the recursive call is within a handler, do not emit a
5538 -- warning, because this is a common idiom: loop until input
5539 -- is correct, catch illegal input in handler and restart.
5545 then
5546 -- For the case of a procedure call. We give the message
5547 -- only if the call is the first statement in a sequence
5548 -- of statements, or if all previous statements are
5549 -- simple assignments. This is simply a heuristic to
5550 -- decrease false positives, without losing too many good
5551 -- warnings. The idea is that these previous statements
5552 -- may affect global variables the procedure depends on.
5553 -- We also exclude raise statements, that may arise from
5554 -- constraint checks and are probably unrelated to the
5555 -- intended control flow.
5559 then
5560 declare
5562 begin
5566 N_Assignment_Statement,
5567 N_Raise_Constraint_Error)
5568 then
5577 -- Do not give warning if we are in a conditional context
5579 declare
5581 begin
5587 then
5592 -- Here warning is to be issued
5595 Error_Msg_N
5597 Error_Msg_N
5609 -- Check obsolescent reference to Ada.Characters.Handling subprogram
5613 -- If subprogram name is a predefined operator, it was given in
5614 -- functional notation. Replace call node with operator node, so
5615 -- that actuals can be resolved appropriately.
5623 then
5629 -- Create a transient scope if the resulting type requires it
5631 -- There are several notable exceptions:
5633 -- a) In init procs, the transient scope overhead is not needed, and is
5634 -- even incorrect when the call is a nested initialization call for a
5635 -- component whose expansion may generate adjust calls. However, if the
5636 -- call is some other procedure call within an initialization procedure
5637 -- (for example a call to Create_Task in the init_proc of the task
5638 -- run-time record) a transient scope must be created around this call.
5640 -- b) Enumeration literal pseudo-calls need no transient scope
5642 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
5643 -- functions) do not use the secondary stack even though the return
5644 -- type may be unconstrained.
5646 -- d) Calls to a build-in-place function, since such functions may
5647 -- allocate their result directly in a target object, and cases where
5648 -- the result does get allocated in the secondary stack are checked for
5649 -- within the specialized Exp_Ch6 procedures for expanding those
5650 -- build-in-place calls.
5652 -- e) If the subprogram is marked Inline_Always, then even if it returns
5653 -- an unconstrained type the call does not require use of the secondary
5654 -- stack. However, inlining will only take place if the body to inline
5655 -- is already present. It may not be available if e.g. the subprogram is
5656 -- declared in a child instance.
5658 -- If this is an initialization call for a type whose construction
5659 -- uses the secondary stack, and it is not a nested call to initialize
5660 -- a component, we do need to create a transient scope for it. We
5661 -- check for this by traversing the type in Check_Initialization_Call.
5667 and then not Debug_Flag_Dot_K
5668 then
5675 and then Debug_Flag_Dot_K
5676 then
5682 then
5685 elsif Full_Expander_Active
5688 and then
5690 or else
5692 then
5695 -- If the call appears within the bounds of a loop, it will
5696 -- be rewritten and reanalyzed, nothing left to do here.
5703 and then not Within_Init_Proc
5704 then
5708 -- A protected function cannot be called within the definition of the
5709 -- enclosing protected type.
5714 then
5715 Error_Msg_NE
5719 -- Propagate interpretation to actuals, and add default expressions
5720 -- where needed.
5725 -- Overloaded literals are rewritten as function calls, for purpose of
5726 -- resolution. After resolution, we can replace the call with the
5727 -- literal itself.
5733 -- Avoid validation, since it is a static function call
5739 -- If the subprogram is not global, then kill all saved values and
5740 -- checks. This is a bit conservative, since in many cases we could do
5741 -- better, but it is not worth the effort. Similarly, we kill constant
5742 -- values. However we do not need to do this for internal entities
5743 -- (unless they are inherited user-defined subprograms), since they
5744 -- are not in the business of molesting local values.
5746 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5747 -- kill all checks and values for calls to global subprograms. This
5748 -- takes care of the case where an access to a local subprogram is
5749 -- taken, and could be passed directly or indirectly and then called
5750 -- from almost any context.
5752 -- Note: we do not do this step till after resolving the actuals. That
5753 -- way we still take advantage of the current value information while
5754 -- scanning the actuals.
5756 -- We suppress killing values if we are processing the nodes associated
5757 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5758 -- type kills all the values as part of analyzing the code that
5759 -- initializes the dispatch tables.
5763 or else Suppress_Value_Tracking_On_Call
5768 then
5769 Kill_Current_Values;
5772 -- If we are warning about unread OUT parameters, this is the place to
5773 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5774 -- after the above call to Kill_Current_Values (since that call clears
5775 -- the Last_Assignment field of all local variables).
5780 then
5781 declare
5785 begin
5795 then
5805 -- If the subprogram is a primitive operation, check whether or not
5806 -- it is a correct dispatching call.
5810 then
5815 and then not In_Instance
5816 then
5820 -- If this is a dispatching call, generate the appropriate reference,
5821 -- for better source navigation in GPS.
5825 then
5828 -- Normal case, not a dispatching call: generate a call reference
5830 else
5838 -- Check for violation of restriction No_Specific_Termination_Handlers
5839 -- and warn on a potentially blocking call to Abort_Task.
5843 or else
5845 then
5852 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
5853 -- timing event violates restriction No_Relative_Delay (AI-0211). We
5854 -- need to check the second argument to determine whether it is an
5855 -- absolute or relative timing event.
5860 then
5864 -- Issue an error for a call to an eliminated subprogram. This routine
5865 -- will not perform the check if the call appears within a default
5866 -- expression.
5870 -- In formal mode, the primitive operations of a tagged type or type
5871 -- extension do not include functions that return the tagged type.
5873 -- Commented out as the call to Is_Inherited_Operation_For_Type may
5874 -- cause an error because the type entity of the parent node of
5875 -- Entity (Name (N) may not be set. ???
5876 -- So why not just add a guard ???
5878 -- if Nkind (N) = N_Function_Call
5879 -- and then Is_Tagged_Type (Etype (N))
5880 -- and then Is_Entity_Name (Name (N))
5881 -- and then Is_Inherited_Operation_For_Type
5882 -- (Entity (Name (N)), Etype (N))
5883 -- then
5884 -- Check_SPARK_Restriction ("function not inherited", N);
5885 -- end if;
5887 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
5888 -- class-wide and the call dispatches on result in a context that does
5889 -- not provide a tag, the call raises Program_Error.
5892 and then In_Instance
5897 then
5898 -- Verify that none of the formals are controlling
5900 declare
5904 begin
5925 -- Check the dimensions of the actuals in the call. For function calls,
5926 -- propagate the dimensions from the returned type to N.
5930 -- All done, evaluate call and deal with elaboration issues
5937 -----------------------------
5938 -- Resolve_Case_Expression --
5939 -----------------------------
5944 begin
5955 -------------------------------
5956 -- Resolve_Character_Literal --
5957 -------------------------------
5963 begin
5964 -- Verify that the character does belong to the type of the context
5969 -- Wide_Wide_Character literals must always be defined, since the set
5970 -- of wide wide character literals is complete, i.e. if a character
5971 -- literal is accepted by the parser, then it is OK for wide wide
5972 -- character (out of range character literals are rejected).
5977 -- Always accept character literal for type Any_Character, which
5978 -- occurs in error situations and in comparisons of literals, both
5979 -- of which should accept all literals.
5984 -- For Standard.Character or a type derived from it, check that the
5985 -- literal is in range.
5992 -- For Standard.Wide_Character or a type derived from it, check that the
5993 -- literal is in range.
6000 -- For Standard.Wide_Wide_Character or a type derived from it, we
6001 -- know the literal is in range, since the parser checked!
6006 -- If the entity is already set, this has already been resolved in a
6007 -- generic context, or comes from expansion. Nothing else to do.
6012 -- Otherwise we have a user defined character type, and we can use the
6013 -- standard visibility mechanisms to locate the referenced entity.
6015 else
6028 -- If we fall through, then the literal does not match any of the
6029 -- entries of the enumeration type. This isn't just a constraint error
6030 -- situation, it is an illegality (see RM 4.2).
6032 Error_Msg_NE
6036 ---------------------------
6037 -- Resolve_Comparison_Op --
6038 ---------------------------
6040 -- Context requires a boolean type, and plays no role in resolution.
6041 -- Processing identical to that for equality operators. The result type is
6042 -- the base type, which matters when pathological subtypes of booleans with
6043 -- limited ranges are used.
6050 begin
6051 -- If this is an intrinsic operation which is not predefined, use the
6052 -- types of its declared arguments to resolve the possibly overloaded
6053 -- operands. Otherwise the operands are unambiguous and specify the
6054 -- expected type.
6059 else
6070 -- Skip remaining processing if already set to Any_Type
6076 -- Deal with other error cases
6080 T = Any_Character
6081 then
6084 else
6092 -- Resolve the operands if types OK
6101 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6102 -- types or array types except String.
6105 Check_SPARK_Restriction
6110 then
6111 Check_SPARK_Restriction
6115 -- Check comparison on unordered enumeration
6121 -- Evaluate the relation (note we do this after the above check since
6122 -- this Eval call may change N to True/False.
6128 -----------------------------------------
6129 -- Resolve_Discrete_Subtype_Indication --
6130 -----------------------------------------
6132 procedure Resolve_Discrete_Subtype_Indication
6135 is
6139 begin
6147 else
6157 Error_Msg_NE
6160 -- Rewrite the constraint as a range of Typ
6161 -- to allow compilation to proceed further.
6173 else
6177 -- Additionally, we must check that the bounds are compatible
6178 -- with the given subtype, which might be different from the
6179 -- type of the context.
6183 -- ??? If the above check statically detects a Constraint_Error
6184 -- it replaces the offending bound(s) of the range R with a
6185 -- Constraint_Error node. When the itype which uses these bounds
6186 -- is frozen the resulting call to Duplicate_Subexpr generates
6187 -- a new temporary for the bounds.
6189 -- Unfortunately there are other itypes that are also made depend
6190 -- on these bounds, so when Duplicate_Subexpr is called they get
6191 -- a forward reference to the newly created temporaries and Gigi
6192 -- aborts on such forward references. This is probably sign of a
6193 -- more fundamental problem somewhere else in either the order of
6194 -- itype freezing or the way certain itypes are constructed.
6196 -- To get around this problem we call Remove_Side_Effects right
6197 -- away if either bounds of R are a Constraint_Error.
6199 declare
6203 begin
6219 -------------------------
6220 -- Resolve_Entity_Name --
6221 -------------------------
6223 -- Used to resolve identifiers and expanded names
6228 begin
6229 -- If garbage from errors, set to Any_Type and return
6236 -- Replace named numbers by corresponding literals. Note that this is
6237 -- the one case where Resolve_Entity_Name must reset the Etype, since
6238 -- it is currently marked as universal.
6248 -- For enumeration literals, we need to make sure that a proper style
6249 -- check is done, since such literals are overloaded, and thus we did
6250 -- not do a style check during the first phase of analysis.
6256 -- Case of subtype name appearing as an operand in expression
6260 -- Allow use of subtype if it is a concurrent type where we are
6261 -- currently inside the body. This will eventually be expanded into a
6262 -- call to Self (for tasks) or _object (for protected objects). Any
6263 -- other use of a subtype is invalid.
6267 then
6270 -- Any other use is an error
6272 else
6273 Error_Msg_N
6277 -- Check discriminant use if entity is discriminant in current scope,
6278 -- i.e. discriminant of record or concurrent type currently being
6279 -- analyzed. Uses in corresponding body are unrestricted.
6284 then
6287 -- A parameterless generic function cannot appear in a context that
6288 -- requires resolution.
6299 then
6302 -- In all other cases, just do the possible static evaluation
6304 else
6305 -- A deferred constant that appears in an expression must have a
6306 -- completion, unless it has been removed by in-place expansion of
6307 -- an aggregate.
6313 and then not In_Spec_Expression
6315 then
6319 then
6321 else
6322 Error_Msg_N (
6331 -------------------
6332 -- Resolve_Entry --
6333 -------------------
6345 -- If the bounds of the entry family being called depend on task
6346 -- discriminants, build a new index subtype where a discriminant is
6347 -- replaced with the value of the discriminant of the target task.
6348 -- The target task is the prefix of the entry name in the call.
6350 -----------------------
6351 -- Actual_Index_Type --
6352 -----------------------
6362 -- If the bound is given by a discriminant, replace with a reference
6363 -- to the discriminant of the same name in the target task. If the
6364 -- entry name is the target of a requeue statement and the entry is
6365 -- in the current protected object, the bound to be used is the
6366 -- discriminal of the object (see Apply_Range_Checks for details of
6367 -- the transformation).
6369 -----------------------------
6370 -- Actual_Discriminant_Ref --
6371 -----------------------------
6377 begin
6382 then
6388 then
6389 -- Note: here Bound denotes a discriminant of the corresponding
6390 -- record type tskV, whose discriminal is a formal of the
6391 -- init-proc tskVIP. What we want is the body discriminal,
6392 -- which is associated to the discriminant of the original
6393 -- concurrent type tsk.
6395 return New_Occurrence_Of
6398 else
6399 Ref :=
6409 -- Start of processing for Actual_Index_Type
6411 begin
6414 then
6417 else
6431 -- Start of processing of Resolve_Entry
6433 begin
6434 -- Find name of entry being called, and resolve prefix of name with its
6435 -- own type. The prefix can be overloaded, and the name and signature of
6436 -- the entry must be taken into account.
6440 -- Case of dealing with entry family within the current tasks
6444 else
6450 -- Entry call to an entry (or entry family) in the current task. This
6451 -- is legal even though the task will deadlock. Rewrite as call to
6452 -- current task.
6454 -- This can also be a call to an entry in an enclosing task. If this
6455 -- is a single task, we have to retrieve its name, because the scope
6456 -- of the entry is the task type, not the object. If the enclosing
6457 -- task is a task type, the identity of the task is given by its own
6458 -- self variable.
6460 -- Finally this can be a requeue on an entry of the same task or
6461 -- protected object.
6468 then
6469 -- S is an enclosing task or protected object. The concurrent
6470 -- declaration has been converted into a type declaration, and
6471 -- the object itself has an object declaration that follows
6472 -- the type in the same declarative part.
6484 -- Call to current task. Will be transformed into call to Self
6491 New_N :=
6494 Selector_Name =>
6501 then
6502 -- Use the entry name (which must be unique at this point) to find
6503 -- the prefix that returns the corresponding task/protected type.
6505 declare
6511 begin
6533 -- Up to this point the expression could have been the actual in a
6534 -- simple entry call, and be given by a named association.
6538 else
6544 ------------------------
6545 -- Resolve_Entry_Call --
6546 ------------------------
6558 begin
6559 -- We kill all checks here, because it does not seem worth the effort to
6560 -- do anything better, an entry call is a big operation.
6562 Kill_All_Checks;
6564 -- Processing of the name is similar for entry calls and protected
6565 -- operation calls. Once the entity is determined, we can complete
6566 -- the resolution of the actuals.
6568 -- The selector may be overloaded, in the case of a protected object
6569 -- with overloaded functions. The type of the context is used for
6570 -- resolution.
6575 then
6576 declare
6580 begin
6599 -- Simple entry call
6607 -- Call to member of entry family
6614 -- We cannot in general check the maximum depth of protected entry calls
6615 -- at compile time. But we can tell that any protected entry call at all
6616 -- violates a specified nesting depth of zero.
6622 -- Use context type to disambiguate a protected function that can be
6623 -- called without actuals and that returns an array type, and where the
6624 -- argument list may be an indexing of the returned value.
6629 and then
6635 and then
6636 Covers
6639 then
6640 declare
6643 begin
6644 Index_Node :=
6646 Prefix =>
6650 -- Since we are correcting a node classification error made by the
6651 -- parser, we call Replace rather than Rewrite.
6664 then
6665 -- Rewrite as call to the precondition wrapper, adding the task
6666 -- object to the list of actuals. If the call is to a member of an
6667 -- entry family, include the index as well.
6669 declare
6673 begin
6682 New_Call :=
6684 Name =>
6693 -- The operation name may have been overloaded. Order the actuals
6694 -- according to the formals of the resolved entity, and set the return
6695 -- type to that of the operation.
6706 -- Create a call reference to the entry
6714 -- Verify that a procedure call cannot masquerade as an entry
6715 -- call where an entry call is expected.
6720 then
6725 then
6730 then
6735 -- After resolution, entry calls and protected procedure calls are
6736 -- changed into entry calls, for expansion. The structure of the node
6737 -- does not change, so it can safely be done in place. Protected
6738 -- function calls must keep their structure because they are
6739 -- subexpressions.
6743 -- A protected operation that is not a function may modify the
6744 -- corresponding object, and cannot apply to a constant. If this
6745 -- is an internal call, the prefix is the type itself.
6751 then
6752 Error_Msg_N
6754 Entry_Name);
6768 -- Protected functions can return on the secondary stack, in which
6769 -- case we must trigger the transient scope mechanism.
6771 elsif Full_Expander_Active
6773 then
6778 -------------------------
6779 -- Resolve_Equality_Op --
6780 -------------------------
6782 -- Both arguments must have the same type, and the boolean context does
6783 -- not participate in the resolution. The first pass verifies that the
6784 -- interpretation is not ambiguous, and the type of the left argument is
6785 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
6786 -- are strings or aggregates, allocators, or Null, they are ambiguous even
6787 -- though they carry a single (universal) type. Diagnose this case here.
6795 -- The resolution rule for if expressions requires that each such must
6796 -- have a unique type. This means that if several dependent expressions
6797 -- are of a non-null anonymous access type, and the context does not
6798 -- impose an expected type (as can be the case in an equality operation)
6799 -- the expression must be rejected.
6802 -- In the case of allocators, make a last-ditch attempt to find a single
6803 -- access type with the right designated type. This is semantically
6804 -- dubious, and of no interest to any real code, but c48008a makes it
6805 -- all worthwhile.
6807 -------------------------
6808 -- Check_If_Expression --
6809 -------------------------
6815 begin
6822 then
6828 -----------------------------
6829 -- Find_Unique_Access_Type --
6830 -----------------------------
6837 begin
6842 else
6854 then
6867 -- Start of processing for Resolve_Equality_Op
6869 begin
6880 T = Any_Character
6881 then
6884 else
6893 then
6902 -- If expressions must have a single type, and if the context does
6903 -- not impose one the dependent expressions cannot be anonymous
6904 -- access types.
6906 -- Why no similar processing for case expressions???
6910 E_Anonymous_Access_Subprogram_Type)
6912 E_Anonymous_Access_Subprogram_Type)
6913 then
6921 -- In SPARK, equality operators = and /= for array types other than
6922 -- String are only defined when, for each index position, the
6923 -- operands have equal static bounds.
6927 -- Protect call to Matching_Static_Array_Bounds to avoid costly
6928 -- operation if not needed.
6936 then
6937 Check_SPARK_Restriction
6942 -- If the unique type is a class-wide type then it will be expanded
6943 -- into a dispatching call to the predefined primitive. Therefore we
6944 -- check here for potential violation of such restriction.
6950 if Warn_On_Redundant_Constructs
6955 then
6956 Error_Msg_N -- CODEFIX
6965 -- If this is an inequality, it may be the implicit inequality
6966 -- created for a user-defined operation, in which case the corres-
6967 -- ponding equality operation is not intrinsic, and the operation
6968 -- cannot be constant-folded. Else fold.
6973 or else Is_Intrinsic_Subprogram
6975 then
6981 then
6985 -- Ada 2005: If one operand is an anonymous access type, convert the
6986 -- other operand to it, to ensure that the underlying types match in
6987 -- the back-end. Same for access_to_subprogram, and the conversion
6988 -- verifies that the types are subtype conformant.
6990 -- We apply the same conversion in the case one of the operands is a
6991 -- private subtype of the type of the other.
6993 -- Why the Expander_Active test here ???
6995 if Full_Expander_Active
6996 and then
6998 E_Anonymous_Access_Subprogram_Type)
7000 then
7020 ----------------------------------
7021 -- Resolve_Explicit_Dereference --
7022 ----------------------------------
7030 -- The candidate prefix type, if overloaded
7035 begin
7041 -- Use the context type to select the prefix that has the correct
7042 -- designated type. Keep the first match, which will be the inner-
7043 -- most.
7050 then
7055 -- Remove access types that do not match, but preserve access
7056 -- to subprogram interpretations, in case a further dereference
7057 -- is needed (see below).
7070 else
7071 -- If no interpretation covers the designated type of the prefix,
7072 -- this is the pathological case where not all implementations of
7073 -- the prefix allow the interpretation of the node as a call. Now
7074 -- that the expected type is known, Remove other interpretations
7075 -- from prefix, rewrite it as a call, and resolve again, so that
7076 -- the proper call node is generated.
7087 New_N :=
7089 Name =>
7100 -- If not overloaded, resolve P with its own type
7102 else
7110 -- If the designated type is a packed unconstrained array type, and the
7111 -- explicit dereference is not in the context of an attribute reference,
7112 -- then we must compute and set the actual subtype, since it is needed
7113 -- by Gigi. The reason we exclude the attribute case is that this is
7114 -- handled fine by Gigi, and in fact we use such attributes to build the
7115 -- actual subtype. We also exclude generated code (which builds actual
7116 -- subtypes directly if they are needed).
7123 then
7127 -- Note: No Eval processing is required for an explicit dereference,
7128 -- because such a name can never be static.
7132 -------------------------------------
7133 -- Resolve_Expression_With_Actions --
7134 -------------------------------------
7137 begin
7141 ---------------------------
7142 -- Resolve_If_Expression --
7143 ---------------------------
7152 begin
7157 -- When the "then" expression is of a scalar subtype different from the
7158 -- result subtype, then insert a conversion to ensure the generation of
7159 -- a constraint check. The same is done for the else part below, again
7160 -- comparing subtypes rather than base types.
7164 then
7169 -- If ELSE expression present, just resolve using the determined type
7177 then
7182 -- If no ELSE expression is present, root type must be Standard.Boolean
7183 -- and we provide a Standard.True result converted to the appropriate
7184 -- Boolean type (in case it is a derived boolean type).
7187 Else_Expr :=
7192 else
7201 -------------------------------
7202 -- Resolve_Indexed_Component --
7203 -------------------------------
7211 begin
7214 -- Use the context type to select the prefix that yields the correct
7215 -- component type.
7217 declare
7224 begin
7231 and then
7232 Covers
7235 then
7244 else
7250 else
7261 else
7268 -- If prefix is access type, dereference to get real array type.
7269 -- Note: we do not apply an access check because the expander always
7270 -- introduces an explicit dereference, and the check will happen there.
7276 -- If name was overloaded, set component type correctly now
7277 -- If a misplaced call to an entry family (which has no index types)
7278 -- return. Error will be diagnosed from calling context.
7282 else
7289 -- The prefix may have resolved to a string literal, in which case its
7290 -- etype has a special representation. This is only possible currently
7291 -- if the prefix is a static concatenation, written in functional
7292 -- notation.
7297 else
7304 else
7315 -- Do not generate the warning on suspicious index if we are analyzing
7316 -- package Ada.Tags; otherwise we will report the warning with the
7317 -- Prims_Ptr field of the dispatch table.
7320 or else not
7322 Ada_Tags)
7323 then
7328 -- If the array type is atomic, and is packed, and we are in a left side
7329 -- context, then this is worth a warning, since we have a situation
7330 -- where the access to the component may cause extra read/writes of
7331 -- the atomic array object, which could be considered unexpected.
7339 then
7347 -----------------------------
7348 -- Resolve_Integer_Literal --
7349 -----------------------------
7352 begin
7357 --------------------------------
7358 -- Resolve_Intrinsic_Operator --
7359 --------------------------------
7369 -- If the operand is a literal, it cannot be the expression in a
7370 -- conversion. Use a qualified expression instead.
7375 begin
7377 Res :=
7383 else
7390 -- Start of processing for Resolve_Intrinsic_Operator
7392 begin
7393 -- We must preserve the original entity in a generic setting, so that
7394 -- the legality of the operation can be verified in an instance.
7409 -- If the result or operand types are private, rewrite with unchecked
7410 -- conversions on the operands and the result, to expose the proper
7411 -- underlying numeric type.
7416 then
7418 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
7419 -- What on earth is this commented out fragment of code???
7423 else
7444 then
7445 -- Add explicit conversion where needed, and save interpretations in
7446 -- case operands are overloaded. If the context is a VMS operation,
7447 -- assert that the conversion is legal (the operands have the proper
7448 -- types to select the VMS intrinsic). Note that in rare cases the
7449 -- VMS operators may be visible, but the default System is being used
7450 -- and Address is a private type.
7461 else
7471 else
7481 else
7486 --------------------------------------
7487 -- Resolve_Intrinsic_Unary_Operator --
7488 --------------------------------------
7490 procedure Resolve_Intrinsic_Unary_Operator
7493 is
7498 begin
7517 else
7522 ------------------------
7523 -- Resolve_Logical_Op --
7524 ------------------------
7529 begin
7532 -- Predefined operations on scalar types yield the base type. On the
7533 -- other hand, logical operations on arrays yield the type of the
7534 -- arguments (and the context).
7538 else
7542 -- OK if this is a VMS-specific intrinsic operation
7547 -- The following test is required because the operands of the operation
7548 -- may be literals, in which case the resulting type appears to be
7549 -- compatible with a signed integer type, when in fact it is compatible
7550 -- only with modular types. If the context itself is universal, the
7551 -- operation is illegal.
7559 Error_Msg_N
7567 then
7571 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
7572 -- is active and the result type is standard Boolean (do not mess with
7573 -- ops that return a nonstandard Boolean type, because something strange
7574 -- is going on).
7576 -- Note: you might expect this replacement to be done during expansion,
7577 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
7578 -- is used, no part of the right operand of an "and" or "or" operator
7579 -- should be executed if the left operand would short-circuit the
7580 -- evaluation of the corresponding "and then" or "or else". If we left
7581 -- the replacement to expansion time, then run-time checks associated
7582 -- with such operands would be evaluated unconditionally, due to being
7583 -- before the condition prior to the rewriting as short-circuit forms
7584 -- during expansion.
7586 if Short_Circuit_And_Or
7589 then
7597 -- Case of OR changed to OR ELSE
7599 else
7607 -- Return now, since analysis of the rewritten ops will take care of
7608 -- other reference bookkeeping and expression folding.
7623 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
7624 -- only when both operands have same static lower and higher bounds. Of
7625 -- course the types have to match, so only check if operands are
7626 -- compatible and the node itself has no errors.
7630 then
7631 declare
7635 begin
7636 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7637 -- operation if not needed.
7644 then
7645 Check_SPARK_Restriction
7654 ---------------------------
7655 -- Resolve_Membership_Op --
7656 ---------------------------
7658 -- The context can only be a boolean type, and does not determine the
7659 -- arguments. Arguments should be unambiguous, but the preference rule for
7660 -- universal types applies.
7670 -- Analysis has determined a unique type for the left operand. Use it to
7671 -- resolve the disjuncts.
7673 ----------------------------
7674 -- Resolve_Set_Membership --
7675 ----------------------------
7681 begin
7687 -- Alternative is an expression, a range
7688 -- or a subtype mark.
7692 then
7699 -- Check for duplicates for discrete case
7702 declare
7711 begin
7712 -- Loop checking duplicates. This is quadratic, but giant sets
7713 -- are unlikely in this context so it's a reasonable choice.
7720 N_Character_Literal)
7722 then
7740 -- Start of processing for Resolve_Membership_Op
7742 begin
7748 Resolve_Set_Membership;
7753 and then
7755 or else
7758 then
7761 -- Ada 2005 (AI-251): Support the following case:
7763 -- type I is interface;
7764 -- type T is tagged ...
7766 -- function Test (O : I'Class) is
7767 -- begin
7768 -- return O in T'Class.
7769 -- end Test;
7771 -- In this case we have nothing else to do. The membership test will be
7772 -- done at run time.
7779 then
7781 else
7785 -- If mixed-mode operations are present and operands are all literal,
7786 -- the only interpretation involves Duration, which is probably not
7787 -- the intention of the programmer.
7802 then
7808 else
7817 ------------------
7818 -- Resolve_Null --
7819 ------------------
7824 begin
7825 -- Handle restriction against anonymous null access values This
7826 -- restriction can be turned off using -gnatdj.
7828 -- Ada 2005 (AI-231): Remove restriction
7831 and then not Debug_Flag_J
7834 then
7835 -- In the common case of a call which uses an explicitly null value
7836 -- for an access parameter, give specialized error message.
7839 Error_Msg_N
7842 -- Standard message for all other cases (are there any?)
7844 else
7845 Error_Msg_N
7850 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
7851 -- assignment to a null-excluding object
7856 then
7858 Insert_Action
7863 else
7870 -- In a distributed context, null for a remote access to subprogram may
7871 -- need to be replaced with a special record aggregate. In this case,
7872 -- return after having done the transformation.
7877 then
7881 -- The null literal takes its type from the context
7886 -----------------------
7887 -- Resolve_Op_Concat --
7888 -----------------------
7892 -- We wish to avoid deep recursion, because concatenations are often
7893 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
7894 -- operands nonrecursively until we find something that is not a simple
7895 -- concatenation (A in this case). We resolve that, and then walk back
7896 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
7897 -- to do the rest of the work at each level. The Parent pointers allow
7898 -- us to avoid recursion, and thus avoid running out of memory. See also
7899 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
7904 begin
7905 -- The following code is equivalent to:
7907 -- Resolve_Op_Concat_First (NN, Typ);
7908 -- Resolve_Op_Concat_Arg (N, ...);
7909 -- Resolve_Op_Concat_Rest (N, Typ);
7911 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
7912 -- operand is a concatenation.
7914 -- Walk down left operands
7916 loop
7925 -- Now (given the above example) NN is A&B and Op1 is A
7927 -- First resolve Op1 ...
7931 -- ... then walk NN back up until we reach N (where we started), calling
7932 -- Resolve_Op_Concat_Rest along the way.
7934 loop
7941 Check_SPARK_Restriction
7946 ---------------------------
7947 -- Resolve_Op_Concat_Arg --
7948 ---------------------------
7950 procedure Resolve_Op_Concat_Arg
7955 is
7959 begin
7961 if Is_Comp
7965 then
7967 else
7971 -- If both Array & Array and Array & Component are visible, there is a
7972 -- potential ambiguity that must be reported.
7977 then
7981 -- If the operation is user-defined and not overloaded use its
7982 -- profile. The operation may be a renaming, in which case it has
7983 -- been rewritten, and we want the original profile.
7988 then
7990 Etype
7994 -- Otherwise an aggregate may match both the array type and the
7995 -- component type.
7997 else
8002 else
8006 then
8007 declare
8012 begin
8017 -- Special-case the error message when the overloading is
8018 -- caused by a function that yields an array and can be
8019 -- called without parameters.
8024 Error_Msg_NE
8026 Error_Msg_NE
8030 else
8038 or else
8040 then
8041 Error_Msg_N -- CODEFIX
8059 else
8064 else
8068 -- Concatenation is restricted in SPARK: each operand must be either a
8069 -- string literal, the name of a string constant, a static character or
8070 -- string expression, or another concatenation. Arg cannot be a
8071 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
8072 -- separately on each final operand, past concatenation operations.
8076 Check_SPARK_Restriction
8084 then
8085 Check_SPARK_Restriction
8089 -- Do not issue error on an operand that is neither a character nor a
8090 -- string, as the error is issued in Resolve_Op_Concat.
8092 else
8099 -----------------------------
8100 -- Resolve_Op_Concat_First --
8101 -----------------------------
8108 begin
8109 -- The parser folds an enormous sequence of concatenations of string
8110 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
8111 -- in the right operand. If the expression resolves to a predefined "&"
8112 -- operator, all is well. Otherwise, the parser's folding is wrong, so
8113 -- we give an error. See P_Simple_Expression in Par.Ch4.
8118 then
8133 ----------------------------
8134 -- Resolve_Op_Concat_Rest --
8135 ----------------------------
8141 begin
8150 -- If this is not a static concatenation, but the result is a string
8151 -- type (and not an array of strings) ensure that static string operands
8152 -- have their subtypes properly constructed.
8156 then
8162 ----------------------
8163 -- Resolve_Op_Expon --
8164 ----------------------
8169 begin
8170 -- Catch attempts to do fixed-point exponentiation with universal
8171 -- operands, which is a case where the illegality is not caught during
8172 -- normal operator analysis.
8182 then
8191 then
8198 then
8202 -- We do the resolution using the base type, because intermediate values
8203 -- in expressions always are of the base type, not a subtype of it.
8217 -- Evaluate the exponentiation operator for dimensioned type
8220 else
8224 -- Set overflow checking bit. Much cleverer code needed here eventually
8225 -- and perhaps the Resolve routines should be separated for the various
8226 -- arithmetic operations, since they will need different processing. ???
8235 --------------------
8236 -- Resolve_Op_Not --
8237 --------------------
8243 -- This function determines if the parent node is a boolean operator or
8244 -- operation (comparison op, membership test, or short circuit form) and
8245 -- the not in question is the left operand of this operation. Note that
8246 -- if the not is in parens, then false is returned.
8248 -----------------------
8249 -- Parent_Is_Boolean --
8250 -----------------------
8253 begin
8257 else
8259 when N_Op_And |
8260 N_Op_Eq |
8261 N_Op_Ge |
8262 N_Op_Gt |
8263 N_Op_Le |
8264 N_Op_Lt |
8265 N_Op_Ne |
8266 N_Op_Or |
8267 N_Op_Xor |
8268 N_In |
8269 N_Not_In |
8270 N_And_Then |
8271 N_Or_Else =>
8281 -- Start of processing for Resolve_Op_Not
8283 begin
8284 -- Predefined operations on scalar types yield the base type. On the
8285 -- other hand, logical operations on arrays yield the type of the
8286 -- arguments (and the context).
8290 else
8297 -- Straightforward case of incorrect arguments
8304 -- Special case of probable missing parens
8308 Error_Msg_N
8311 else
8312 Error_Msg_N
8319 -- OK resolution of NOT
8321 else
8322 -- Warn if non-boolean types involved. This is a case like not a < b
8323 -- where a and b are modular, where we will get (not a) < b and most
8324 -- likely not (a < b) was intended.
8326 if Warn_On_Questionable_Missing_Parens
8328 and then Parent_Is_Boolean
8329 then
8333 -- Warn on double negation if checking redundant constructs
8335 if Warn_On_Redundant_Constructs
8340 then
8344 -- Complete resolution and evaluation of NOT
8354 -----------------------------
8355 -- Resolve_Operator_Symbol --
8356 -----------------------------
8358 -- Nothing to be done, all resolved already
8364 begin
8368 ----------------------------------
8369 -- Resolve_Qualified_Expression --
8370 ----------------------------------
8378 begin
8381 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8382 -- operation if not needed.
8389 then
8390 Check_SPARK_Restriction
8394 -- A qualified expression requires an exact match of the type, class-
8395 -- wide matching is not allowed. However, if the qualifying type is
8396 -- specific and the expression has a class-wide type, it may still be
8397 -- okay, since it can be the result of the expansion of a call to a
8398 -- dispatching function, so we also have to check class-wideness of the
8399 -- type of the expression's original node.
8402 or else
8406 then
8410 -- If the target type is unconstrained, then we reset the type of the
8411 -- result from the type of the expression. For other cases, the actual
8412 -- subtype of the expression is the target type.
8416 then
8424 -------------------
8425 -- Resolve_Range --
8426 -------------------
8433 -- Returns True if N is of the form X'First .. X'Last where X is the
8434 -- same entity for both attributes.
8436 --------------------
8437 -- First_Last_Ref --
8438 --------------------
8444 begin
8449 then
8450 declare
8453 begin
8457 then
8466 -- Start of processing for Resolve_Range
8468 begin
8473 -- Check for inappropriate range on unordered enumeration type
8477 -- Exclude X'First .. X'Last if X is the same entity for both
8479 and then not First_Last_Ref
8480 then
8487 -- We have to check the bounds for being within the base range as
8488 -- required for a non-static context. Normally this is automatic and
8489 -- done as part of evaluating expressions, but the N_Range node is an
8490 -- exception, since in GNAT we consider this node to be a subexpression,
8491 -- even though in Ada it is not. The circuit in Sem_Eval could check for
8492 -- this, but that would put the test on the main evaluation path for
8493 -- expressions.
8498 -- Check for an ambiguous range over character literals. This will
8499 -- happen with a membership test involving only literals.
8507 -- If bounds are static, constant-fold them, so size computations are
8508 -- identical between front-end and back-end. Do not perform this
8509 -- transformation while analyzing generic units, as type information
8510 -- would be lost when reanalyzing the constant node in the instance.
8523 --------------------------
8524 -- Resolve_Real_Literal --
8525 --------------------------
8530 begin
8531 -- Special processing for fixed-point literals to make sure that the
8532 -- value is an exact multiple of small where this is required. We skip
8533 -- this for the universal real case, and also for generic types.
8539 then
8540 declare
8547 begin
8548 -- Case of literal is not an exact multiple of the Small
8552 -- For a source program literal for a decimal fixed-point type,
8553 -- this is statically illegal (RM 4.9(36)).
8558 then
8562 -- Generate a warning if literal from source
8565 and then Warn_On_Bad_Fixed_Value
8566 then
8567 Error_Msg_N
8569 N);
8572 -- Replace literal by a value that is the exact representation
8573 -- of a value of the type, i.e. a multiple of the small value,
8574 -- by truncation, since Machine_Rounds is false for all GNAT
8575 -- fixed-point types (RM 4.9(38)).
8585 -- In all cases, set the corresponding integer field
8591 -- Now replace the actual type by the expected type as usual
8597 -----------------------
8598 -- Resolve_Reference --
8599 -----------------------
8604 begin
8605 -- Replace general access with specific type
8613 -- If we are taking the reference of a volatile entity, then treat it as
8614 -- a potential modification of this entity. This is too conservative,
8615 -- but necessary because remove side effects can cause transformations
8616 -- of normal assignments into reference sequences that otherwise fail to
8617 -- notice the modification.
8624 --------------------------------
8625 -- Resolve_Selected_Component --
8626 --------------------------------
8641 -- Check whether this is the initialization of a component within an
8642 -- init proc (by assignment or call to another init proc). If true,
8643 -- there is no need for a discriminant check.
8645 --------------------
8646 -- Init_Component --
8647 --------------------
8650 begin
8651 return Inside_Init_Proc
8657 -- Start of processing for Resolve_Selected_Component
8659 begin
8662 -- Use the context type to select the prefix that has a selector
8663 -- of the correct name and type.
8671 else
8675 -- Locate selected component. For a private prefix the selector
8676 -- can denote a discriminant.
8680 -- The visible components of a class-wide type are those of
8681 -- the root type.
8691 then
8698 else
8702 Error_Msg_N
8707 else
8710 -- There may be an implicit dereference. Retrieve
8711 -- designated record type.
8715 else
8721 -- Resolution chooses the new interpretation.
8722 -- Find the component with the right name.
8727 loop
8748 else
8749 -- Resolve prefix with its type
8754 -- Generate cross-reference. We needed to wait until full overloading
8755 -- resolution was complete to do this, since otherwise we can't tell if
8756 -- we are an lvalue or not.
8760 else
8764 -- If prefix is an access type, the node will be transformed into an
8765 -- explicit dereference during expansion. The type of the node is the
8766 -- designated type of that of the prefix.
8771 else
8782 and then not Init_Component
8783 then
8791 -- If the prefix is a record conversion, this may be a renamed
8792 -- discriminant whose bounds differ from those of the original
8793 -- one, so we must ensure that a range check is performed.
8798 then
8802 -- Note: No Eval processing is required, because the prefix is of a
8803 -- record type, or protected type, and neither can possibly be static.
8805 -- If the array type is atomic, and is packed, and we are in a left side
8806 -- context, then this is worth a warning, since we have a situation
8807 -- where the access to the component may cause extra read/writes of the
8808 -- atomic array object, which could be considered unexpected.
8816 then
8817 Error_Msg_N
8819 Error_Msg_N
8826 -------------------
8827 -- Resolve_Shift --
8828 -------------------
8835 begin
8836 -- We do the resolution using the base type, because intermediate values
8837 -- in expressions always are of the base type, not a subtype of it.
8850 ---------------------------
8851 -- Resolve_Short_Circuit --
8852 ---------------------------
8859 begin
8863 -- Check for issuing warning for always False assert/check, this happens
8864 -- when assertions are turned off, in which case the pragma Assert/Check
8865 -- was transformed into:
8867 -- if False and then <condition> then ...
8869 -- and we detect this pattern
8871 if Warn_On_Assertion_Failure
8878 then
8879 declare
8882 begin
8885 then
8886 -- Don't want to warn if original condition is explicit False
8888 declare
8890 Original_Node
8891 (Expression
8893 begin
8896 then
8898 else
8899 -- Issue warning. We do not want the deletion of the
8900 -- IF/AND-THEN to take this message with it. We achieve
8901 -- this by making sure that the expanded code points to
8902 -- the Sloc of the expression, not the original pragma.
8904 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
8905 -- The source location of the expression is not usually
8906 -- the best choice here. For example, it gets located on
8907 -- the last AND keyword in a chain of boolean expressiond
8908 -- AND'ed together. It is best to put the message on the
8909 -- first character of the assertion, which is the effect
8910 -- of the First_Node call here.
8912 Error_Msg_F
8914 Expression
8919 -- Similar processing for Check pragma
8923 then
8924 -- Don't want to warn if original condition is explicit False
8926 declare
8928 Original_Node
8929 (Expression
8931 begin
8934 then
8937 -- Post warning
8939 else
8940 -- Again use Error_Msg_F rather than Error_Msg_N, see
8941 -- comment above for an explanation of why we do this.
8943 Error_Msg_F
8945 Expression
8953 -- Continue with processing of short circuit
8962 -------------------
8963 -- Resolve_Slice --
8964 -------------------
8972 begin
8975 -- Use the context type to select the prefix that yields the correct
8976 -- array type.
8978 declare
8985 begin
8993 then
9001 else
9006 else
9017 else
9027 -- If the prefix is an access to an unconstrained array, we must use
9028 -- the actual subtype of the object to perform the index checks. The
9029 -- object denoted by the prefix is implicit in the node, so we build
9030 -- an explicit representation for it in order to compute the actual
9031 -- subtype.
9036 declare
9040 begin
9051 then
9054 -- If the name is a selected component that depends on discriminants,
9055 -- build an actual subtype for it. This can happen only when the name
9056 -- itself is overloaded; otherwise the actual subtype is created when
9057 -- the selected component is analyzed.
9060 and then Full_Analysis
9062 then
9063 declare
9066 begin
9071 -- Maybe this should just be "else", instead of checking for the
9072 -- specific case of slice??? This is needed for the case where the
9073 -- prefix is an Image attribute, which gets expanded to a slice, and so
9074 -- has a constrained subtype which we want to use for the slice range
9075 -- check applied below (the range check won't get done if the
9076 -- unconstrained subtype of the 'Image is used).
9082 -- If name was overloaded, set slice type correctly now
9086 -- If the range is specified by a subtype mark, no resolution is
9087 -- necessary. Else resolve the bounds, and apply needed checks.
9092 else
9100 -- Ensure that side effects in the bounds are properly handled
9105 -- Do not apply the range check to nodes associated with the
9106 -- frontend expansion of the dispatch table. We first check
9107 -- if Ada.Tags is already loaded to avoid the addition of an
9108 -- undesired dependence on such run-time unit.
9110 if not Tagged_Type_Expansion
9111 or else not
9117 then
9125 -- Check bad use of type with predicates
9128 Bad_Predicated_Subtype_Use
9132 -- Otherwise here is where we check suspicious indexes
9143 ----------------------------
9144 -- Resolve_String_Literal --
9145 ----------------------------
9156 begin
9157 -- For a string appearing in a concatenation, defer creation of the
9158 -- string_literal_subtype until the end of the resolution of the
9159 -- concatenation, because the literal may be constant-folded away. This
9160 -- is a useful optimization for long concatenation expressions.
9162 -- If the string is an aggregate built for a single character (which
9163 -- happens in a non-static context) or a is null string to which special
9164 -- checks may apply, we build the subtype. Wide strings must also get a
9165 -- string subtype if they come from a one character aggregate. Strings
9166 -- generated by attributes might be static, but it is often hard to
9167 -- determine whether the enclosing context is static, so we generate
9168 -- subtypes for them as well, thus losing some rarer optimizations ???
9169 -- Same for strings that come from a static conversion.
9171 Need_Check :=
9180 -- If the resolving type is itself a string literal subtype, we can just
9181 -- reuse it, since there is no point in creating another.
9187 and then not Need_Check
9189 N_Attribute_Reference,
9190 N_Qualified_Expression,
9191 N_Type_Conversion)
9192 then
9195 -- Otherwise we must create a string literal subtype. Note that the
9196 -- whole idea of string literal subtypes is simply to avoid the need
9197 -- for building a full fledged array subtype for each literal.
9199 else
9205 or else Need_Check
9206 then
9213 then
9219 -- The validity of a null string has been checked in the call to
9220 -- Eval_String_Literal.
9225 -- Always accept string literal with component type Any_Character, which
9226 -- occurs in error situations and in comparisons of literals, both of
9227 -- which should accept all literals.
9232 -- If the type is bit-packed, then we always transform the string
9233 -- literal into a full fledged aggregate.
9238 -- Deal with cases of Wide_Wide_String, Wide_String, and String
9240 else
9241 -- For Standard.Wide_Wide_String, or any other type whose component
9242 -- type is Standard.Wide_Wide_Character, we know that all the
9243 -- characters in the string must be acceptable, since the parser
9244 -- accepted the characters as valid character literals.
9249 -- For the case of Standard.String, or any other type whose component
9250 -- type is Standard.Character, we must make sure that there are no
9251 -- wide characters in the string, i.e. that it is entirely composed
9252 -- of characters in range of type Character.
9254 -- If the string literal is the result of a static concatenation, the
9255 -- test has already been performed on the components, and need not be
9256 -- repeated.
9260 then
9264 -- If we are out of range, post error. This is one of the
9265 -- very few places that we place the flag in the middle of
9266 -- a token, right under the offending wide character. Not
9267 -- quite clear if this is right wrt wide character encoding
9268 -- sequences, but it's only an error message!
9270 Error_Msg
9277 -- For the case of Standard.Wide_String, or any other type whose
9278 -- component type is Standard.Wide_Character, we must make sure that
9279 -- there are no wide characters in the string, i.e. that it is
9280 -- entirely composed of characters in range of type Wide_Character.
9282 -- If the string literal is the result of a static concatenation,
9283 -- the test has already been performed on the components, and need
9284 -- not be repeated.
9288 then
9292 -- If we are out of range, post error. This is one of the
9293 -- very few places that we place the flag in the middle of
9294 -- a token, right under the offending wide character.
9296 -- This is not quite right, because characters in general
9297 -- will take more than one character position ???
9299 Error_Msg
9306 -- If the root type is not a standard character, then we will convert
9307 -- the string into an aggregate and will let the aggregate code do
9308 -- the checking. Standard Wide_Wide_Character is also OK here.
9310 else
9314 -- See if the component type of the array corresponding to the string
9315 -- has compile time known bounds. If yes we can directly check
9316 -- whether the evaluation of the string will raise constraint error.
9317 -- Otherwise we need to transform the string literal into the
9318 -- corresponding character aggregate and let the aggregate code do
9319 -- the checking.
9323 -- Check for the case of full range, where we are definitely OK
9329 -- Here the range is not the complete base type range, so check
9331 declare
9339 begin
9342 then
9348 then
9349 Apply_Compile_Time_Constraint_Error
9351 CE_Range_Check_Failed,
9362 -- If we got here we meed to transform the string literal into the
9363 -- equivalent qualified positional array aggregate. This is rather
9364 -- heavy artillery for this situation, but it is hard work to avoid.
9366 declare
9371 begin
9372 -- Build the character literals, we give them source locations that
9373 -- correspond to the string positions, which is a bit tricky given
9374 -- the possible presence of wide character escape sequences.
9388 -- Should we have a call to Skip_Wide here ???
9390 -- ??? else
9391 -- Skip_Wide (P);
9399 Expression =>
9406 -----------------------------
9407 -- Resolve_Subprogram_Info --
9408 -----------------------------
9411 begin
9415 -----------------------------
9416 -- Resolve_Type_Conversion --
9417 -----------------------------
9429 -- Set to False to suppress cases where we want to suppress the test
9430 -- for redundancy to avoid possible false positives on this warning.
9432 begin
9433 if not Conv_OK
9435 then
9439 -- If the Operand Etype is Universal_Fixed, then the conversion is
9440 -- never redundant. We need this check because by the time we have
9441 -- finished the rather complex transformation, the conversion looks
9442 -- redundant when it is not.
9447 -- If the operand is marked as Any_Fixed, then special processing is
9448 -- required. This is also a case where we suppress the test for a
9449 -- redundant conversion, since most certainly it is not redundant.
9454 -- Mixed-mode operation involving a literal. Context must be a fixed
9455 -- type which is applied to the literal subsequently.
9463 or else
9465 then
9466 -- Return if expression is ambiguous
9471 -- If nothing else, the available fixed type is Duration
9473 else
9477 -- Resolve the real operand with largest available precision
9481 else
9487 -- If the operand is a literal (it could be a non-static and
9488 -- illegal exponentiation) check whether the use of Duration
9489 -- is potentially inaccurate.
9494 then
9495 Error_Msg_N
9498 Error_Msg_N
9505 then
9508 else
9517 -- In SPARK, a type conversion between array types should be restricted
9518 -- to types which have matching static bounds.
9520 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9521 -- operation if not needed.
9528 then
9529 Check_SPARK_Restriction
9533 -- In formal mode, the operand of an ancestor type conversion must be an
9534 -- object (not an expression).
9542 then
9548 -- Note: we do the Eval_Type_Conversion call before applying the
9549 -- required checks for a subtype conversion. This is important, since
9550 -- both are prepared under certain circumstances to change the type
9551 -- conversion to a constraint error node, but in the case of
9552 -- Eval_Type_Conversion this may reflect an illegality in the static
9553 -- case, and we would miss the illegality (getting only a warning
9554 -- message), if we applied the type conversion checks first.
9558 -- Even when evaluation is not possible, we may be able to simplify the
9559 -- conversion or its expression. This needs to be done before applying
9560 -- checks, since otherwise the checks may use the original expression
9561 -- and defeat the simplifications. This is specifically the case for
9562 -- elimination of the floating-point Truncation attribute in
9563 -- float-to-int conversions.
9567 -- If after evaluation we still have a type conversion, then we may need
9568 -- to apply checks required for a subtype conversion.
9570 -- Skip these type conversion checks if universal fixed operands
9571 -- operands involved, since range checks are handled separately for
9572 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
9578 then
9582 -- Issue warning for conversion of simple object to its own type. We
9583 -- have to test the original nodes, since they may have been rewritten
9584 -- by various optimizations.
9588 -- Here we test for a redundant conversion if the warning mode is
9589 -- active (and was not locally reset), and we have a type conversion
9590 -- from source not appearing in a generic instance.
9592 if Test_Redundant
9595 and then not In_Instance
9596 then
9600 -- If the node is part of a larger expression, the Target_Type
9601 -- may not be the original type of the node if the context is a
9602 -- condition. Recover original type to see if conversion is needed.
9606 then
9610 -- If we have an entity name, then give the warning if the entity
9611 -- is the right type, or if it is a loop parameter covered by the
9612 -- original type (that's needed because loop parameters have an
9613 -- odd subtype coming from the bounds).
9616 and then
9618 or else
9622 -- If not an entity, then type of expression must match
9625 then
9626 -- One more check, do not give warning if the analyzed conversion
9627 -- has an expression with non-static bounds, and the bounds of the
9628 -- target are static. This avoids junk warnings in cases where the
9629 -- conversion is necessary to establish staticness, for example in
9630 -- a case statement.
9634 then
9637 -- Finally, if this type conversion occurs in a context requiring
9638 -- a prefix, and the expression is a qualified expression then the
9639 -- type conversion is not redundant, since a qualified expression
9640 -- is not a prefix, whereas a type conversion is. For example, "X
9641 -- := T'(Funx(...)).Y;" is illegal because a selected component
9642 -- requires a prefix, but a type conversion makes it legal: "X :=
9643 -- T(T'(Funx(...))).Y;"
9645 -- In Ada 2012, a qualified expression is a name, so this idiom is
9646 -- no longer needed, but we still suppress the warning because it
9647 -- seems unfriendly for warnings to pop up when you switch to the
9648 -- newer language version.
9652 N_Indexed_Component,
9653 N_Selected_Component,
9654 N_Slice,
9655 N_Explicit_Dereference)
9656 then
9659 -- Never warn on conversion to Long_Long_Integer'Base since
9660 -- that is most likely an artifact of the extended overflow
9661 -- checking and comes from complex expanded code.
9666 -- Here we give the redundant conversion warning. If it is an
9667 -- entity, give the name of the entity in the message. If not,
9668 -- just mention the expression.
9670 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
9672 else
9675 Error_Msg_NE -- CODEFIX
9678 else
9679 Error_Msg_NE
9687 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
9688 -- No need to perform any interface conversion if the type of the
9689 -- expression coincides with the target type.
9692 and then Full_Expander_Active
9694 then
9695 declare
9699 begin
9711 -- Conversion from interface type
9715 -- Ada 2005 (AI-217): Handle entities from limited views
9719 Error_Msg_NE -- CODEFIX
9722 Error_Msg_N
9724 N);
9727 and then not
9730 then
9732 Error_Msg_NE -- CODEFIX
9735 Error_Msg_N
9737 N);
9739 else
9743 -- Conversion to interface type
9747 -- Handle subtypes
9753 if not Interface_Present_In_Ancestor
9756 then
9759 -- The static analysis is not enough to know if the
9760 -- interface is implemented or not. Hence we must pass
9761 -- the work to the expander to generate code to evaluate
9762 -- the conversion at run time.
9766 else
9769 Error_Msg_N
9774 else
9781 -- Ada 2012: if target type has predicates, the result requires a
9782 -- predicate check. If the context is a call to another predicate
9783 -- check we must prevent infinite recursion.
9789 then
9792 else
9798 ----------------------
9799 -- Resolve_Unary_Op --
9800 ----------------------
9809 begin
9812 Check_SPARK_Restriction
9816 -- Deal with intrinsic unary operators
9822 then
9827 -- Deal with universal cases
9830 or else
9832 then
9839 -- Generate warning for expressions like abs (x mod 2)
9841 if Warn_On_Redundant_Constructs
9843 then
9847 Error_Msg_N -- CODEFIX
9852 -- Deal with reference generation
9859 -- Set overflow checking bit. Much cleverer code needed here eventually
9860 -- and perhaps the Resolve routines should be separated for the various
9861 -- arithmetic operations, since they will need different processing ???
9869 -- Generate warning for expressions like -5 mod 3 for integers. No need
9870 -- to worry in the floating-point case, since parens do not affect the
9871 -- result so there is no point in giving in a warning.
9873 declare
9882 begin
9883 if Warn_On_Questionable_Missing_Parens
9887 then
9890 -- We are looking for cases where the right operand is not
9891 -- parenthesized, and is a binary operator, multiply, divide, or
9892 -- mod. These are the cases where the grouping can affect results.
9896 then
9897 -- For mod, we always give the warning, since the value is
9898 -- affected by the parenthesization (e.g. (-5) mod 315 /=
9899 -- -(5 mod 315)). But for the other cases, the only concern is
9900 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
9901 -- overflows, but (-2) * 64 does not). So we try to give the
9902 -- message only when overflow is possible.
9906 then
9911 else
9917 else
9921 -- Note that the test below is deliberately excluding the
9922 -- largest negative number, since that is a potentially
9923 -- troublesome case (e.g. -2 * x, where the result is the
9924 -- largest negative integer has an overflow with 2 * x).
9931 -- For the multiplication case, the only case we have to worry
9932 -- about is when (-a)*b is exactly the largest negative number
9933 -- so that -(a*b) can cause overflow. This can only happen if
9934 -- a is a power of 2, and more generally if any operand is a
9935 -- constant that is not a power of 2, then the parentheses
9936 -- cannot affect whether overflow occurs. We only bother to
9937 -- test the left most operand
9939 -- Loop looking at left operands for one that has known value
9946 -- Operand value of 0 or 1 skips warning
9951 -- Otherwise check power of 2, if power of 2, warn, if
9952 -- anything else, skip warning.
9954 else
9958 else
9967 -- Keep looking at left operands
9972 -- For rem or "/" we can only have a problematic situation
9973 -- if the divisor has a value of minus one or one. Otherwise
9974 -- overflow is impossible (divisor > 1) or we have a case of
9975 -- division by zero in any case.
9980 then
9984 -- If we fall through warning should be issued
9986 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
9988 Error_Msg_N
9995 ----------------------------------
9996 -- Resolve_Unchecked_Expression --
9997 ----------------------------------
9999 procedure Resolve_Unchecked_Expression
10002 is
10003 begin
10008 ---------------------------------------
10009 -- Resolve_Unchecked_Type_Conversion --
10010 ---------------------------------------
10012 procedure Resolve_Unchecked_Type_Conversion
10015 is
10021 begin
10022 -- Resolve operand using its own type
10029 ------------------------------
10030 -- Rewrite_Operator_As_Call --
10031 ------------------------------
10038 begin
10045 New_N :=
10056 ------------------------------
10057 -- Rewrite_Renamed_Operator --
10058 ------------------------------
10060 procedure Rewrite_Renamed_Operator
10064 is
10069 begin
10070 -- Rewrite the operator node using the real operator, not its renaming.
10071 -- Exclude user-defined intrinsic operations of the same name, which are
10072 -- treated separately and rewritten as calls.
10081 -- Indicate that both the original entity and its renaming are
10082 -- referenced at this point.
10093 -- If the context type is private, add the appropriate conversions so
10094 -- that the operator is applied to the full view. This is done in the
10095 -- routines that resolve intrinsic operators.
10099 then
10101 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
10102 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
10115 -- Operator renames a user-defined operator of the same name. Use the
10116 -- original operator in the node, which is the one Gigi knows about.
10123 -----------------------
10124 -- Set_Slice_Subtype --
10125 -----------------------
10127 -- Build an implicit subtype declaration to represent the type delivered by
10128 -- the slice. This is an abbreviated version of an array subtype. We define
10129 -- an index subtype for the slice, using either the subtype name or the
10130 -- discrete range of the slice. To be consistent with index usage elsewhere
10131 -- we create a list header to hold the single index. This list is not
10132 -- otherwise attached to the syntax tree.
10143 begin
10147 else
10148 -- We force the evaluation of a range. This is definitely needed in
10149 -- the renamed case, and seems safer to do unconditionally. Note in
10150 -- any case that since we will create and insert an Itype referring
10151 -- to this range, we must make sure any side effect removal actions
10152 -- are inserted before the Itype definition.
10163 -- Take a new copy of Drange (where bounds have been rewritten to
10164 -- reference side-effect-free names). Using a separate tree ensures
10165 -- that further expansion (e.g. while rewriting a slice assignment
10166 -- into a FOR loop) does not attempt to remove side effects on the
10167 -- bounds again (which would cause the bounds in the index subtype
10168 -- definition to refer to temporaries before they are defined) (the
10169 -- reason is that some names are considered side effect free here
10170 -- for the subtype, but not in the context of a loop iteration
10171 -- scheme).
10192 -- The Etype of the existing Slice node is reset to this slice subtype.
10193 -- Its bounds are obtained from its first index.
10197 -- For packed slice subtypes, freeze immediately (except in the case of
10198 -- being in a "spec expression" where we never freeze when we first see
10199 -- the expression).
10204 -- For all other cases insert an itype reference in the slice's actions
10205 -- so that the itype is frozen at the proper place in the tree (i.e. at
10206 -- the point where actions for the slice are analyzed). Note that this
10207 -- is different from freezing the itype immediately, which might be
10208 -- premature (e.g. if the slice is within a transient scope). This needs
10209 -- to be done only if expansion is enabled.
10216 --------------------------------
10217 -- Set_String_Literal_Subtype --
10218 --------------------------------
10226 begin
10238 -- The low bound is set from the low bound of the corresponding index
10239 -- type. Note that we do not store the high bound in the string literal
10240 -- subtype, but it can be deduced if necessary from the length and the
10241 -- low bound.
10246 -- If the lower bound is not static we create a range for the string
10247 -- literal, using the index type and the known length of the literal.
10248 -- The index type is not necessarily Positive, so the upper bound is
10249 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
10251 else
10252 declare
10258 Prefix =>
10262 Left_Opnd =>
10265 Prefix =>
10267 Expressions =>
10269 Right_Opnd =>
10278 begin
10280 Set_String_Literal_Low_Bound
10283 else
10284 -- If the index type is an enumeration type, build bounds
10285 -- expression with attributes.
10287 Set_String_Literal_Low_Bound
10291 Prefix =>
10298 -- Build bona fide subtype for the string, and wrap it in an
10299 -- unchecked conversion, because the backend expects the
10300 -- String_Literal_Subtype to have a static lower bound.
10302 Index_Subtype :=
10309 -- In the context, the Index_Type may already have a constraint,
10310 -- so use common base type on string subtype. The base type may
10311 -- be used when generating attributes of the string, for example
10312 -- in the context of a slice assignment.
10337 ------------------------------
10338 -- Simplify_Type_Conversion --
10339 ------------------------------
10342 begin
10344 declare
10349 begin
10351 and then
10358 -- Special processing required if the conversion is the expression
10359 -- of a Truncation attribute reference. In this case we replace:
10361 -- ityp (ftyp'Truncation (x))
10363 -- by
10365 -- ityp (x)
10367 -- with the Float_Truncate flag set, which is more efficient.
10369 then
10378 -----------------------------
10379 -- Unique_Fixed_Point_Type --
10380 -----------------------------
10389 -- Give error messages for true ambiguity. Messages are posted on node
10390 -- N, and entities T1, T2 are the possible interpretations.
10392 -----------------------
10393 -- Fixed_Point_Error --
10394 -----------------------
10397 begin
10403 -- Start of processing for Unique_Fixed_Point_Type
10405 begin
10406 -- The operations on Duration are visible, so Duration is always a
10407 -- possible interpretation.
10411 -- Look for fixed-point types in enclosing scopes
10420 then
10422 Fixed_Point_Error;
10424 else
10435 -- Look for visible fixed type declarations in the context
10446 then
10448 Fixed_Point_Error;
10450 else
10463 Error_Msg_NE
10465 else
10466 Error_Msg_NE
10473 ----------------------
10474 -- Valid_Conversion --
10475 ----------------------
10477 function Valid_Conversion
10482 is
10486 function Conversion_Check
10489 -- Little routine to post Msg if Valid is False, returns Valid value
10491 -- The following are badly named, this kind of overloading is actively
10492 -- confusing in reading code, please rename to something like
10493 -- Error_Msg_N_If_Reporting ???
10496 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
10498 procedure Error_Msg_NE
10502 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
10504 function Valid_Tagged_Conversion
10507 -- Specifically test for validity of tagged conversions
10510 -- Check index and component conformance, and accessibility levels if
10511 -- the component types are anonymous access types (Ada 2005).
10513 ----------------------
10514 -- Conversion_Check --
10515 ----------------------
10517 function Conversion_Check
10520 is
10521 begin
10522 if not Valid
10524 -- A generic unit has already been analyzed and we have verified
10525 -- that a particular conversion is OK in that context. Since the
10526 -- instance is reanalyzed without relying on the relationships
10527 -- established during the analysis of the generic, it is possible
10528 -- to end up with inconsistent views of private types. Do not emit
10529 -- the error message in such cases. The rest of the machinery in
10530 -- Valid_Conversion still ensures the proper compatibility of
10531 -- target and operand types.
10533 and then not In_Instance
10534 then
10541 -----------------
10542 -- Error_Msg_N --
10543 -----------------
10546 begin
10552 ------------------
10553 -- Error_Msg_NE --
10554 ------------------
10556 procedure Error_Msg_NE
10560 is
10561 begin
10567 ----------------------------
10568 -- Valid_Array_Conversion --
10569 ----------------------------
10572 is
10587 begin
10588 -- Error if wrong number of dimensions
10590 if
10592 then
10593 Error_Msg_N
10597 -- Number of dimensions matches
10599 else
10600 -- Loop through indexes of the two arrays
10608 -- Error if index types are incompatible
10614 then
10615 Error_Msg_N
10617 Operand);
10625 -- If component types have same base type, all set
10630 -- Here if base types of components are not the same. The only
10631 -- time this is allowed is if we have anonymous access types.
10633 -- The conversion of arrays of anonymous access types can lead
10634 -- to dangling pointers. AI-392 formalizes the accessibility
10635 -- checks that must be applied to such conversions to prevent
10636 -- out-of-scope references.
10638 elsif Ekind_In
10640 E_Anonymous_Access_Subprogram_Type)
10642 and then
10644 then
10647 then
10649 Error_Msg_N
10652 Error_Msg_N
10654 Operand);
10661 -- Conversion not allowed because of accessibility levels
10663 else
10664 Error_Msg_N
10670 else
10674 -- All other cases where component base types do not match
10676 else
10677 Error_Msg_N
10679 Operand);
10683 -- Check that component subtypes statically match. For numeric
10684 -- types this means that both must be either constrained or
10685 -- unconstrained. For enumeration types the bounds must match.
10686 -- All of this is checked in Subtypes_Statically_Match.
10688 if not Subtypes_Statically_Match
10690 then
10691 Error_Msg_N
10700 -----------------------------
10701 -- Valid_Tagged_Conversion --
10702 -----------------------------
10704 function Valid_Tagged_Conversion
10707 is
10708 begin
10709 -- Upward conversions are allowed (RM 4.6(22))
10713 then
10716 -- Downward conversion are allowed if the operand is class-wide
10717 -- (RM 4.6(23)).
10721 then
10726 then
10727 return
10731 -- Ada 2005 (AI-251): The conversion to/from interface types is
10732 -- always valid
10737 -- If the operand is a class-wide type obtained through a limited_
10738 -- with clause, and the context includes the non-limited view, use
10739 -- it to determine whether the conversion is legal.
10745 then
10750 then
10753 else
10754 Error_Msg_NE
10761 -- Start of processing for Valid_Conversion
10763 begin
10767 declare
10775 begin
10776 -- Remove procedure calls, which syntactically cannot appear in
10777 -- this context, but which cannot be removed by type checking,
10778 -- because the context does not impose a type.
10780 -- When compiling for VMS, spurious ambiguities can be produced
10781 -- when arithmetic operations have a literal operand and return
10782 -- System.Address or a descendant of it. These ambiguities are
10783 -- otherwise resolved by the context, but for conversions there
10784 -- is no context type and the removal of the spurious operations
10785 -- must be done explicitly here.
10787 -- The node may be labelled overloaded, but still contain only one
10788 -- interpretation because others were discarded earlier. If this
10789 -- is the case, retain the single interpretation if legal.
10797 then
10798 -- More than one candidate interpretation is available
10808 then
10835 -- If the interpretation involves a standard operator, use
10836 -- the location of the type, which may be user-defined.
10840 else
10844 Error_Msg_N -- CODEFIX
10849 else
10853 Error_Msg_N -- CODEFIX
10865 -- Numeric types
10869 -- A universal fixed expression can be converted to any numeric type
10874 -- Also no need to check when in an instance or inlined body, because
10875 -- the legality has been established when the template was analyzed.
10876 -- Furthermore, numeric conversions may occur where only a private
10877 -- view of the operand type is visible at the instantiation point.
10878 -- This results in a spurious error if we check that the operand type
10879 -- is a numeric type.
10881 -- Note: in a previous version of this unit, the following tests were
10882 -- applied only for generated code (Comes_From_Source set to False),
10883 -- but in fact the test is required for source code as well, since
10884 -- this situation can arise in source code.
10889 -- Otherwise we need the conversion check
10891 else
10892 return Conversion_Check
10897 -- Array types
10903 then
10906 else
10910 -- Ada 2005 (AI-251): Anonymous access types where target references an
10911 -- interface type.
10914 E_Anonymous_Access_Type)
10916 then
10917 -- Check the static accessibility rule of 4.6(17). Note that the
10918 -- check is not enforced when within an instance body, since the
10919 -- RM requires such cases to be caught at run time.
10921 -- If the operand is a rewriting of an allocator no check is needed
10922 -- because there are no accessibility issues.
10930 then
10931 -- In an instance, this is a run-time check, but one we know
10932 -- will fail, so generate an appropriate warning. The raise
10933 -- will be generated by Expand_N_Type_Conversion.
10936 Error_Msg_N
10938 Operand);
10939 Error_Msg_N
10942 else
10943 Error_Msg_N
10945 Operand);
10949 -- Special accessibility checks are needed in the case of access
10950 -- discriminants declared for a limited type.
10954 then
10955 -- When the operand is a selected access discriminant the check
10956 -- needs to be made against the level of the object denoted by
10957 -- the prefix of the selected name (Object_Access_Level handles
10958 -- checking the prefix of the operand for this case).
10963 then
10964 -- In an instance, this is a run-time check, but one we know
10965 -- will fail, so generate an appropriate warning. The raise
10966 -- will be generated by Expand_N_Type_Conversion.
10969 Error_Msg_N
10972 Error_Msg_N
10974 Operand);
10975 else
10976 Error_Msg_N
10983 -- The case of a reference to an access discriminant from
10984 -- within a limited type declaration (which will appear as
10985 -- a discriminal) is always illegal because the level of the
10986 -- discriminant is considered to be deeper than any (nameable)
10987 -- access type.
10991 and then
10994 then
10995 Error_Msg_N
10997 Operand);
11005 -- General and anonymous access types
11008 E_Anonymous_Access_Type)
11009 and then
11010 Conversion_Check
11012 and then not
11014 E_Access_Protected_Subprogram_Type),
11016 then
11019 then
11020 Error_Msg_N
11025 -- Check the static accessibility rule of 4.6(17). Note that the
11026 -- check is not enforced when within an instance body, since the RM
11027 -- requires such cases to be caught at run time.
11032 N_Object_Declaration
11033 then
11034 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
11035 -- conversions from an anonymous access type to a named general
11036 -- access type. Such conversions are not allowed in the case of
11037 -- access parameters and stand-alone objects of an anonymous
11038 -- access type. The implicit conversion case is recognized by
11039 -- testing that Comes_From_Source is False and that it's been
11040 -- rewritten. The Comes_From_Source test isn't sufficient because
11041 -- nodes in inlined calls to predefined library routines can have
11042 -- Comes_From_Source set to False. (Is there a better way to test
11043 -- for implicit conversions???)
11050 then
11053 -- Implicit conversions aren't allowed for objects of an
11054 -- anonymous access type, since such objects have nonstatic
11055 -- levels in Ada 2012.
11058 N_Object_Declaration
11059 then
11060 Error_Msg_N
11065 -- Implicit conversions aren't allowed for anonymous access
11066 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
11067 -- is done to exclude anonymous access results.
11071 N_Function_Specification,
11072 N_Procedure_Specification)
11073 then
11074 Error_Msg_N
11079 -- This is a case where there's an enclosing object whose
11080 -- to which the "statically deeper than" relationship does
11081 -- not apply (such as an access discriminant selected from
11082 -- a dereference of an access parameter).
11086 then
11087 Error_Msg_N
11092 -- In other cases, the level of the operand's type must be
11093 -- statically less deep than that of the target type, else
11094 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
11098 then
11099 Error_Msg_N
11108 then
11109 -- In an instance, this is a run-time check, but one we know
11110 -- will fail, so generate an appropriate warning. The raise
11111 -- will be generated by Expand_N_Type_Conversion.
11114 Error_Msg_N
11116 Operand);
11117 Error_Msg_N
11120 else
11121 -- Avoid generation of spurious error message
11124 Error_Msg_N
11126 Operand);
11132 -- Special accessibility checks are needed in the case of access
11133 -- discriminants declared for a limited type.
11137 then
11138 -- When the operand is a selected access discriminant the check
11139 -- needs to be made against the level of the object denoted by
11140 -- the prefix of the selected name (Object_Access_Level handles
11141 -- checking the prefix of the operand for this case).
11146 then
11147 -- In an instance, this is a run-time check, but one we know
11148 -- will fail, so generate an appropriate warning. The raise
11149 -- will be generated by Expand_N_Type_Conversion.
11152 Error_Msg_N
11155 Error_Msg_N
11157 Operand);
11159 else
11160 Error_Msg_N
11167 -- The case of a reference to an access discriminant from
11168 -- within a limited type declaration (which will appear as
11169 -- a discriminal) is always illegal because the level of the
11170 -- discriminant is considered to be deeper than any (nameable)
11171 -- access type.
11174 and then
11177 then
11178 Error_Msg_N
11180 Operand);
11186 -- In the presence of limited_with clauses we have to use non-limited
11187 -- views, if available.
11191 -- Helper function to handle limited views
11193 --------------------------
11194 -- Full_Designated_Type --
11195 --------------------------
11200 begin
11201 -- Handle the limited view of a type
11206 then
11208 else
11213 -- Local Declarations
11221 -- Start of processing for Check_Limited
11223 begin
11227 else
11229 Error_Msg_NE
11234 -- Ada 2005 AI-384: legality rule is symmetric in both
11235 -- designated types. The conversion is legal (with possible
11236 -- constraint check) if either designated type is
11237 -- unconstrained.
11240 or else
11242 and then
11245 then
11246 -- Special case, if Value_Size has been used to make the
11247 -- sizes different, the conversion is not allowed even
11248 -- though the subtypes statically match.
11253 then
11254 Error_Msg_NE
11257 Error_Msg_NE
11262 -- Normal case where conversion is allowed
11264 else
11268 else
11269 Error_Msg_NE
11277 -- Access to subprogram types. If the operand is an access parameter,
11278 -- the type has a deeper accessibility that any master, and cannot be
11279 -- assigned. We must make an exception if the conversion is part of an
11280 -- assignment and the target is the return object of an extended return
11281 -- statement, because in that case the accessibility check takes place
11282 -- after the return.
11286 then
11290 and then
11294 then
11295 Error_Msg_N
11297 Operand);
11298 Error_Msg_N
11301 Operand);
11303 Error_Msg_NE
11308 -- Check that the designated types are subtype conformant
11314 -- Check the static accessibility rule of 4.6(20)
11318 then
11319 Error_Msg_N
11321 Operand);
11323 -- Check that if the operand type is declared in a generic body,
11324 -- then the target type must be declared within that same body
11325 -- (enforces last sentence of 4.6(20)).
11328 declare
11334 begin
11341 Error_Msg_N
11350 -- Remote subprogram access types
11354 then
11355 -- It is valid to convert from one RAS type to another provided
11356 -- that their specification statically match.
11358 Check_Subtype_Conformant
11361 Old_Id =>
11363 Err_Loc =>
11364 N);
11367 -- If it was legal in the generic, it's legal in the instance
11372 -- If both are tagged types, check legality of view conversions
11375 and then
11377 then
11380 -- Types derived from the same root type are convertible
11385 -- In an instance or an inlined body, there may be inconsistent views of
11386 -- the same type, or of types derived from a common root.
11389 and then
11392 then
11395 -- Special check for common access type error case
11399 then
11401 Error_Msg_NE -- CODEFIX
11405 else