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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
83 -----------------------
84 -- Local Subprograms --
85 -----------------------
87 -- Second pass (top-down) type checking and overload resolution procedures
88 -- Typ is the type required by context. These procedures propagate the type
89 -- information recursively to the descendants of N. If the node is not
90 -- overloaded, its Etype is established in the first pass. If overloaded,
91 -- the Resolve routines set the correct type. For arith. operators, the
92 -- Etype is the base type of the context.
94 -- Note that Resolve_Attribute is separated off in Sem_Attr
96 function Bad_Unordered_Enumeration_Reference
99 -- Node N contains a potentially dubious reference to type T, either an
100 -- explicit comparison, or an explicit range. This function returns True
101 -- if the type T is an enumeration type for which No pragma Order has been
102 -- given, and the reference N is not in the same extended source unit as
103 -- the declaration of T.
106 -- Enforce the restrictions on the use of discriminants when constraining
107 -- a component of a discriminated type (record or concurrent type).
110 -- Given a node for an operator associated with type T, check that
111 -- the operator is visible. Operators all of whose operands are
112 -- universal must be checked for visibility during resolution
113 -- because their type is not determinable based on their operands.
115 procedure Check_Fully_Declared_Prefix
118 -- Check that the type of the prefix of a dereference is not incomplete
121 -- Given a call node, N, which is known to occur immediately within the
122 -- subprogram being called, determines whether it is a detectable case of
123 -- an infinite recursion, and if so, outputs appropriate messages. Returns
124 -- True if an infinite recursion is detected, and False otherwise.
127 -- If the type of the object being initialized uses the secondary stack
128 -- directly or indirectly, create a transient scope for the call to the
129 -- init proc. This is because we do not create transient scopes for the
130 -- initialization of individual components within the init proc itself.
131 -- Could be optimized away perhaps?
134 -- N is the node for a logical operator. If the operator is predefined, and
135 -- the root type of the operands is Standard.Boolean, then a check is made
136 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
137 -- the style check for Style_Check_Boolean_And_Or.
140 -- Determine whether E is an access type declared by an access declaration,
141 -- and not an (anonymous) allocator type.
144 -- Utility to check whether the entity for an operator is a predefined
145 -- operator, in which case the expression is left as an operator in the
146 -- tree (else it is rewritten into a call). An instance of an intrinsic
147 -- conversion operation may be given an operator name, but is not treated
148 -- like an operator. Note that an operator that is an imported back-end
149 -- builtin has convention Intrinsic, but is expected to be rewritten into
150 -- a call, so such an operator is not treated as predefined by this
151 -- predicate.
154 -- If a default expression in entry call N depends on the discriminants
155 -- of the task, it must be replaced with a reference to the discriminant
156 -- of the task being called.
158 procedure Resolve_Op_Concat_Arg
163 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
164 -- concatenation operator. The operand is either of the array type or of
165 -- the component type. If the operand is an aggregate, and the component
166 -- type is composite, this is ambiguous if component type has aggregates.
169 -- Does the first part of the work of Resolve_Op_Concat
172 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
173 -- has been resolved. See Resolve_Op_Concat for details.
210 function Operator_Kind
213 -- Utility to map the name of an operator into the corresponding Node. Used
214 -- by other node rewriting procedures.
217 -- Resolve actuals of call, and add default expressions for missing ones.
218 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
219 -- called subprogram.
222 -- Called from Resolve_Call, when the prefix denotes an entry or element
223 -- of entry family. Actuals are resolved as for subprograms, and the node
224 -- is rebuilt as an entry call. Also called for protected operations. Typ
225 -- is the context type, which is used when the operation is a protected
226 -- function with no arguments, and the return value is indexed.
229 -- A call to a user-defined intrinsic operator is rewritten as a call to
230 -- the corresponding predefined operator, with suitable conversions. Note
231 -- that this applies only for intrinsic operators that denote predefined
232 -- operators, not ones that are intrinsic imports of back-end builtins.
235 -- Ditto, for unary operators (arithmetic ones and "not" on signed
236 -- integer types for VMS).
239 -- If an operator node resolves to a call to a user-defined operator,
240 -- rewrite the node as a function call.
242 procedure Make_Call_Into_Operator
246 -- Inverse transformation: if an operator is given in functional notation,
247 -- then after resolving the node, transform into an operator node, so
248 -- that operands are resolved properly. Recall that predefined operators
249 -- do not have a full signature and special resolution rules apply.
251 procedure Rewrite_Renamed_Operator
255 -- An operator can rename another, e.g. in an instantiation. In that
256 -- case, the proper operator node must be constructed and resolved.
259 -- The String_Literal_Subtype is built for all strings that are not
260 -- operands of a static concatenation operation. If the argument is
261 -- not a N_String_Literal node, then the call has no effect.
264 -- Build subtype of array type, with the range specified by the slice
267 -- Called after N has been resolved and evaluated, but before range checks
268 -- have been applied. Currently simplifies a combination of floating-point
269 -- to integer conversion and Truncation attribute.
272 -- A universal_fixed expression in an universal context is unambiguous if
273 -- there is only one applicable fixed point type. Determining whether there
274 -- is only one requires a search over all visible entities, and happens
275 -- only in very pathological cases (see 6115-006).
277 -------------------------
278 -- Ambiguous_Character --
279 -------------------------
284 begin
288 -- First the ones in Standard
293 -- Include Wide_Wide_Character in Ada 2005 mode
299 -- Now any other types that match
309 -------------------------
310 -- Analyze_And_Resolve --
311 -------------------------
314 begin
320 begin
325 -- 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 -- AI05-144-2: Check dangerous order dependence within an expression
2868 -- that is not a subexpression. Exclude RHS of an assignment, because
2869 -- both sides may have side-effects and the check must be performed
2870 -- over the statement.
2872 if Nkind (Parent (N)) not in N_Subexpr
2873 and then Nkind (Parent (N)) /= N_Assignment_Statement
2874 and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
2875 then
2876 Check_Order_Dependence;
2877 end if;
2879 -- The expression is definitely NOT overloaded at this point, so
2880 -- we reset the Is_Overloaded flag to avoid any confusion when
2881 -- reanalyzing the node.
2883 Set_Is_Overloaded (N, False);
2885 -- Freeze expression type, entity if it is a name, and designated
2886 -- type if it is an allocator (RM 13.14(10,11,13)).
2888 -- Now that the resolution of the type of the node is complete, and
2889 -- we did not detect an error, we can expand this node. We skip the
2890 -- expand call if we are in a default expression, see section
2891 -- "Handling of Default Expressions" in Sem spec.
2893 Debug_A_Exit ("resolving ", N, " (done)");
2895 -- We unconditionally freeze the expression, even if we are in
2896 -- default expression mode (the Freeze_Expression routine tests this
2897 -- flag and only freezes static types if it is set).
2899 -- Ada 2012 (AI05-177): Expression functions do not freeze. Only
2900 -- their use (in an expanded call) freezes.
2902 if Ekind (Proper_Current_Scope) /= E_Function
2903 or else Nkind (Original_Node (Unit_Declaration_Node
2904 (Proper_Current_Scope))) /= N_Expression_Function
2905 then
2906 Freeze_Expression (N);
2907 end if;
2909 -- Now we can do the expansion
2911 Expand (N);
2912 end if;
2913 end Resolve;
2915 -------------
2916 -- Resolve --
2917 -------------
2919 -- Version with check(s) suppressed
2921 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2922 begin
2923 if Suppress = All_Checks then
2924 declare
2925 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
2926 begin
2927 Scope_Suppress.Suppress := (others => True);
2928 Resolve (N, Typ);
2929 Scope_Suppress.Suppress := Sva;
2930 end;
2932 else
2933 declare
2934 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
2935 begin
2936 Scope_Suppress.Suppress (Suppress) := True;
2937 Resolve (N, Typ);
2938 Scope_Suppress.Suppress (Suppress) := Svg;
2939 end;
2940 end if;
2941 end Resolve;
2943 -------------
2944 -- Resolve --
2945 -------------
2947 -- Version with implicit type
2949 procedure Resolve (N : Node_Id) is
2950 begin
2951 Resolve (N, Etype (N));
2952 end Resolve;
2954 ---------------------
2955 -- Resolve_Actuals --
2956 ---------------------
2958 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2959 Loc : constant Source_Ptr := Sloc (N);
2960 A : Node_Id;
2961 F : Entity_Id;
2962 A_Typ : Entity_Id;
2963 F_Typ : Entity_Id;
2964 Prev : Node_Id := Empty;
2965 Orig_A : Node_Id;
2967 procedure Check_Argument_Order;
2968 -- Performs a check for the case where the actuals are all simple
2969 -- identifiers that correspond to the formal names, but in the wrong
2970 -- order, which is considered suspicious and cause for a warning.
2972 procedure Check_Prefixed_Call;
2973 -- If the original node is an overloaded call in prefix notation,
2975 -- Try_Object_Operation has already verified that there is a valid
2976 -- interpretation, but the form of the actual can only be determined
2977 -- once the primitive operation is identified.
2980 -- If the actual is missing in a call, insert in the actuals list
2981 -- an instance of the default expression. The insertion is always
2982 -- a named association.
2985 -- Check whether T1 and T2, or their full views, are derived from a
2986 -- common type. Used to enforce the restrictions on array conversions
2987 -- of AI95-00246.
2990 -- Predicate to determine whether an actual that is a concatenation
2991 -- will be evaluated statically and does not need a transient scope.
2992 -- This must be determined before the actual is resolved and expanded
2993 -- because if needed the transient scope must be introduced earlier.
2995 --------------------------
2996 -- Check_Argument_Order --
2997 --------------------------
3000 begin
3001 -- Nothing to do if no parameters, or original node is neither a
3002 -- function call nor a procedure call statement (happens in the
3003 -- operator-transformed-to-function call case), or the call does
3004 -- not come from source, or this warning is off.
3006 if not Warn_On_Parameter_Order
3010 then
3014 declare
3017 begin
3018 -- Nothing to do if only one parameter
3024 -- Here if at least two arguments
3026 declare
3032 -- Set True if an out of order case is found
3034 begin
3035 -- Collect identifier names of actuals, fail if any actual is
3036 -- not a simple identifier, and record max length of name.
3042 else
3048 -- If we got this far, all actuals are identifiers and the list
3049 -- of their names is stored in the Actuals array.
3054 -- If we ran out of formals, that's odd, probably an error
3055 -- which will be detected elsewhere, but abandon the search.
3061 -- If name matches and is in order OK
3066 else
3067 -- If no match, see if it is elsewhere in list and if so
3068 -- flag potential wrong order if type is compatible.
3072 and then
3074 then
3080 -- No match
3088 -- If Formals left over, also probably an error, skip warning
3094 -- Here we give the warning if something was out of order
3097 Error_Msg_N
3104 -------------------------
3105 -- Check_Prefixed_Call --
3106 -------------------------
3115 begin
3116 -- Check whether the call is a prefixed call, with or without
3117 -- additional actuals.
3120 or else
3126 then
3129 then
3130 -- Introduce dereference on object in prefix
3132 New_A :=
3140 then
3141 -- Introduce an implicit 'Access in prefix
3144 Error_Msg_NE
3160 --------------------
3161 -- Insert_Default --
3162 --------------------
3168 begin
3169 -- Missing argument in call, nothing to insert
3174 else
3175 -- Note that we do a full New_Copy_Tree, so that any associated
3176 -- Itypes are properly copied. This may not be needed any more,
3177 -- but it does no harm as a safety measure! Defaults of a generic
3178 -- formal may be out of bounds of the corresponding actual (see
3179 -- cc1311b) and an additional check may be required.
3181 Actval :=
3182 New_Copy_Tree
3189 then
3195 then
3198 then
3199 -- If default is a real literal, do not introduce a
3200 -- conversion whose effect may depend on the run-time
3201 -- size of universal real.
3205 else
3216 -- Resolve aggregates with their base type, to avoid scope
3217 -- anomalies: the subtype was first built in the subprogram
3218 -- declaration, and the current call may be nested.
3222 else
3226 else
3229 -- See note above concerning aggregates
3233 then
3236 -- Resolve entities with their own type, which may differ from
3237 -- the type of a reference in a generic context (the view
3238 -- swapping mechanism did not anticipate the re-analysis of
3239 -- default values in calls).
3244 else
3249 -- If default is a tag indeterminate function call, propagate tag
3250 -- to obtain proper dispatching.
3254 then
3260 -- If the default expression raises constraint error, then just
3261 -- silently replace it with an N_Raise_Constraint_Error node, since
3262 -- we already gave the warning on the subprogram spec. If node is
3263 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3264 -- the warnings removal machinery.
3268 then
3276 Assoc :=
3281 -- Case of insertion is first named actual
3285 then
3292 else
3296 else
3300 -- Case of insertion is not first named actual
3302 else
3303 Set_Next_Named_Actual
3315 -------------------
3316 -- Same_Ancestor --
3317 -------------------
3323 begin
3326 then
3332 then
3339 --------------------------
3340 -- Static_Concatenation --
3341 --------------------------
3344 begin
3351 -- Concatenation is static when both operands are static and
3352 -- the concatenation operator is a predefined one.
3355 and then
3357 and then
3362 declare
3364 begin
3367 and then
3371 else
3377 -- Start of processing for Resolve_Actuals
3379 begin
3380 Check_Argument_Order;
3383 Check_Prefixed_Call;
3392 -- If we have an error in any actual or formal, indicated by a type
3393 -- of Any_Type, then abandon resolution attempt, and set result type
3394 -- to Any_Type.
3398 then
3403 -- Case where actual is present
3405 -- If the actual is an entity, generate a reference to it now. We
3406 -- do this before the actual is resolved, because a formal of some
3407 -- protected subprogram, or a task discriminant, will be rewritten
3408 -- during expansion, and the source entity reference may be lost.
3413 then
3419 then
3431 then
3432 -- If style checking mode on, check match of formal name
3440 -- If the formal is Out or In_Out, do not resolve and expand the
3441 -- conversion, because it is subsequently expanded into explicit
3442 -- temporaries and assignments. However, the object of the
3443 -- conversion can be resolved. An exception is the case of tagged
3444 -- type conversion with a class-wide actual. In that case we want
3445 -- the tag check to occur and no temporary will be needed (no
3446 -- representation change can occur) and the parameter is passed by
3447 -- reference, so we go ahead and resolve the type conversion.
3448 -- Another exception is the case of reference to component or
3449 -- subcomponent of a bit-packed array, in which case we want to
3450 -- defer expansion to the point the in and out assignments are
3451 -- performed.
3456 then
3459 then
3460 -- In a view conversion, the conversion must be legal in
3461 -- both directions, and thus both component types must be
3462 -- aliased, or neither (4.6 (8)).
3464 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3465 -- the privacy requirement should not apply to generic
3466 -- types, and should be checked in an instance. ARG query
3467 -- is in order ???
3471 then
3472 Error_Msg_N
3476 -- Comment here??? what set of cases???
3478 elsif
3480 then
3481 -- Check view conv between unrelated by ref array types
3485 then
3486 Error_Msg_N
3490 -- In Ada 2005 mode, check view conversion component
3491 -- type cannot be private, tagged, or volatile. Note
3492 -- that we only apply this to source conversions. The
3493 -- generated code can contain conversions which are
3494 -- not subject to this test, and we cannot extract the
3495 -- component type in such cases since it is not present.
3499 then
3500 declare
3502 Component_Type
3504 begin
3509 then
3510 Error_Msg_N
3521 -- Resolve expression if conversion is all OK
3526 then
3530 -- If the actual is a function call that returns a limited
3531 -- unconstrained object that needs finalization, create a
3532 -- transient scope for it, so that it can receive the proper
3533 -- finalization list.
3538 and then Full_Expander_Active
3540 then
3544 -- A small optimization: if one of the actuals is a concatenation
3545 -- create a block around a procedure call to recover stack space.
3546 -- This alleviates stack usage when several procedure calls in
3547 -- the same statement list use concatenation. We do not perform
3548 -- this wrapping for code statements, where the argument is a
3549 -- static string, and we want to preserve warnings involving
3550 -- sequences of such statements.
3554 and then Full_Expander_Active
3555 and then
3559 then
3563 else
3567 and then
3570 then
3571 Error_Msg_N
3584 -- (Ada 2005: AI-251): If the actual is an allocator whose
3585 -- directly designated type is a class-wide interface, we build
3586 -- an anonymous access type to use it as the type of the
3587 -- allocator. Later, when the subprogram call is expanded, if
3588 -- the interface has a secondary dispatch table the expander
3589 -- will add a type conversion to force the correct displacement
3590 -- of the pointer.
3593 declare
3599 begin
3602 then
3610 -- Ada 2005, AI-162:If the actual is an allocator, the
3611 -- innermost enclosing statement is the master of the
3612 -- created object. This needs to be done with expansion
3613 -- enabled only, otherwise the transient scope will not
3614 -- be removed in the expansion of the wrapped construct.
3617 and then Full_Expander_Active
3618 then
3624 -- (Ada 2005): The call may be to a primitive operation of
3625 -- a tagged synchronized type, declared outside of the type.
3626 -- In this case the controlling actual must be converted to
3627 -- its corresponding record type, which is the formal type.
3628 -- The actual may be a subtype, either because of a constraint
3629 -- or because it is a generic actual, so use base type to
3630 -- locate concurrent type.
3637 then
3638 -- If the actual is overloaded, look for an interpretation
3639 -- that has a synchronized type.
3644 else
3645 declare
3649 begin
3654 then
3664 declare
3667 begin
3670 else
3674 -- Tagged synchronized type (case 1): the actual is a
3675 -- concurrent type.
3679 then
3681 Unchecked_Convert_To
3685 -- Tagged synchronized type (case 2): the formal is a
3686 -- concurrent type.
3689 and then Present
3694 then
3697 -- Common case
3699 else
3703 else
3705 -- not a synchronized operation.
3716 N_Procedure_Call_Statement)
3717 then
3718 -- In formal mode, check that actual parameters matching
3719 -- formals of tagged types are objects (or ancestor type
3720 -- conversions of objects), not general expressions.
3727 declare
3732 begin
3734 Check_SPARK_Restriction
3737 -- In formal mode, the only view conversions are those
3738 -- involving ancestor conversion of an extended type.
3740 elsif not
3746 then
3747 if Ekind_In
3749 then
3750 Check_SPARK_Restriction
3753 else
3754 Check_SPARK_Restriction
3758 else
3763 else
3767 -- In formal mode, the only view conversions are those
3768 -- involving ancestor conversion of an extended type.
3772 then
3773 Check_SPARK_Restriction
3779 -- Save actual for subsequent check on order dependence, and
3780 -- indicate whether actual is modifiable. For AI05-0144-2.
3782 -- If this is a call to a reference function that is the result
3783 -- of expansion, as in element iterator loops, this does not lead
3784 -- to a dangerous order dependence: only subsequent use of the
3785 -- denoted element might, in some enclosing call.
3789 then
3793 -- For mode IN, if actual is an entity, and the type of the formal
3794 -- has warnings suppressed, then we reset Never_Set_In_Source for
3795 -- the calling entity. The reason for this is to catch cases like
3796 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3797 -- uses trickery to modify an IN parameter.
3804 then
3808 -- Perform error checks for IN and IN OUT parameters
3812 -- Check unset reference. For scalar parameters, it is clearly
3813 -- wrong to pass an uninitialized value as either an IN or
3814 -- IN-OUT parameter. For composites, it is also clearly an
3815 -- error to pass a completely uninitialized value as an IN
3816 -- parameter, but the case of IN OUT is trickier. We prefer
3817 -- not to give a warning here. For example, suppose there is
3818 -- a routine that sets some component of a record to False.
3819 -- It is perfectly reasonable to make this IN-OUT and allow
3820 -- either initialized or uninitialized records to be passed
3821 -- in this case.
3823 -- For partially initialized composite values, we also avoid
3824 -- warnings, since it is quite likely that we are passing a
3825 -- partially initialized value and only the initialized fields
3826 -- will in fact be read in the subprogram.
3831 then
3835 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3836 -- actual to a nested call, since this is case of reading an
3837 -- out parameter, which is not allowed.
3842 then
3847 -- Case of OUT or IN OUT parameter
3851 -- For an Out parameter, check for useless assignment. Note
3852 -- that we can't set Last_Assignment this early, because we may
3853 -- kill current values in Resolve_Call, and that call would
3854 -- clobber the Last_Assignment field.
3856 -- Note: call Warn_On_Useless_Assignment before doing the check
3857 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3858 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3859 -- reflects the last assignment, not this one!
3866 then
3871 -- Validate the form of the actual. Note that the call to
3872 -- Is_OK_Variable_For_Out_Formal generates the required
3873 -- reference in this case.
3875 -- A call to an initialization procedure for an aggregate
3876 -- component may initialize a nested component of a constant
3877 -- designated object. In this context the object is variable.
3881 then
3885 -- What's the following about???
3889 else
3890 Kill_All_Checks;
3899 -- Apply appropriate range checks for in, out, and in-out
3900 -- parameters. Out and in-out parameters also need a separate
3901 -- check, if there is a type conversion, to make sure the return
3902 -- value meets the constraints of the variable before the
3903 -- conversion.
3905 -- Gigi looks at the check flag and uses the appropriate types.
3906 -- For now since one flag is used there is an optimization which
3907 -- might not be done in the In Out case since Gigi does not do
3908 -- any analysis. More thought required about this ???
3912 -- Apply predicate checks, unless this is a call to the
3913 -- predicate check function itself, which would cause an
3914 -- infinite recursion.
3918 then
3922 -- Apply required constraint checks
3935 then
3941 then
3947 then
3950 else
3954 -- Ada 2005 (AI-231): Note that the controlling parameter case
3955 -- already existed in Ada 95, which is partially checked
3956 -- elsewhere (see Checks), and we don't want the warning
3957 -- message to differ.
3962 then
3964 Apply_Compile_Time_Constraint_Error
3970 Apply_Compile_Time_Constraint_Error
3982 Apply_Scalar_Range_Check
3984 else
3985 Apply_Range_Check
3989 else
3994 then
3996 else
4002 -- An actual associated with an access parameter is implicitly
4003 -- converted to the anonymous access type of the formal and must
4004 -- satisfy the legality checks for access conversions.
4008 Error_Msg_N
4012 -- If the actual is an access selected component of a variable,
4013 -- the call may modify its designated object. It is reasonable
4014 -- to treat this as a potential modification of the enclosing
4015 -- record, to prevent spurious warnings that it should be
4016 -- declared as a constant, because intuitively programmers
4017 -- regard the designated subcomponent as part of the record.
4022 then
4027 -- Check bad case of atomic/volatile argument (RM C.6(12))
4031 then
4034 then
4035 Error_Msg_NE
4041 then
4042 Error_Msg_NE
4048 -- Check that subprograms don't have improper controlling
4049 -- arguments (RM 3.9.2 (9)).
4051 -- A primitive operation may have an access parameter of an
4052 -- incomplete tagged type, but a dispatching call is illegal
4053 -- if the type is still incomplete.
4059 declare
4061 begin
4065 then
4066 Error_Msg_NE
4080 then
4085 then
4087 Error_Msg_NE
4091 -- Apply the checks described in 3.10.2(27): if the context is a
4092 -- specific access-to-object, the actual cannot be class-wide.
4093 -- Use base type to exclude access_to_subprogram cases.
4100 and then
4105 -- Disable these checks for call to imported C++ subprograms
4107 and then not
4111 then
4112 Error_Msg_N
4117 Error_Msg_NE
4124 -- If it is a named association, treat the selector_name as a
4125 -- proper identifier, and mark the corresponding entity. Ignore
4126 -- this reference in Alfa mode, as it refers to an entity not in
4127 -- scope at the point of reference, so the reference should be
4128 -- ignored for computing effects of subprograms.
4131 and then not Alfa_Mode
4132 then
4147 -- Case where actual is not present
4149 else
4150 Insert_Default;
4157 -----------------------
4158 -- Resolve_Allocator --
4159 -----------------------
4171 procedure Check_Allocator_Discrim_Accessibility
4174 -- Check that accessibility level associated with an access discriminant
4175 -- initialized in an allocator by the expression Disc_Exp is not deeper
4176 -- than the level of the allocator type Alloc_Typ. An error message is
4177 -- issued if this condition is violated. Specialized checks are done for
4178 -- the cases of a constraint expression which is an access attribute or
4179 -- an access discriminant.
4182 -- If the allocator is an actual in a call, it is allowed to be class-
4183 -- wide when the context is not because it is a controlling actual.
4185 -------------------------------------------
4186 -- Check_Allocator_Discrim_Accessibility --
4187 -------------------------------------------
4189 procedure Check_Allocator_Discrim_Accessibility
4192 is
4193 begin
4196 then
4197 Error_Msg_N
4200 -- When the expression is an Access attribute the level of the prefix
4201 -- object must not be deeper than that of the allocator's type.
4205 Attribute_Access
4208 then
4209 Error_Msg_N
4211 Disc_Exp);
4213 -- When the expression is an access discriminant the check is against
4214 -- the level of the prefix object.
4220 then
4221 Error_Msg_N
4223 Disc_Exp);
4225 -- All other cases are legal
4227 else
4232 ----------------------------
4233 -- In_Dispatching_Context --
4234 ----------------------------
4239 begin
4245 -- Start of processing for Resolve_Allocator
4247 begin
4248 -- Replace general access with specific type
4258 -- For qualified expression, resolve the expression using the
4259 -- given subtype (nothing to do for type mark, subtype indication)
4264 and then not In_Dispatching_Context
4265 then
4266 Error_Msg_N
4273 -- A qualified expression requires an exact match of the type,
4274 -- class-wide matching is not allowed.
4279 then
4283 -- Calls to build-in-place functions are not currently supported in
4284 -- allocators for access types associated with a simple storage pool.
4285 -- Supporting such allocators may require passing additional implicit
4286 -- parameters to build-in-place functions (or a significant revision
4287 -- of the current b-i-p implementation to unify the handling for
4288 -- multiple kinds of storage pools). ???
4292 then
4293 declare
4296 begin
4298 and then
4299 Present (Get_Rep_Pragma
4301 then
4302 Error_Msg_N
4309 -- A special accessibility check is needed for allocators that
4310 -- constrain access discriminants. The level of the type of the
4311 -- expression used to constrain an access discriminant cannot be
4312 -- deeper than the type of the allocator (in contrast to access
4313 -- parameters, where the level of the actual can be arbitrary).
4315 -- We can't use Valid_Conversion to perform this check because
4316 -- in general the type of the allocator is unrelated to the type
4317 -- of the access discriminant.
4321 then
4328 then
4331 -- Get the first component expression of the aggregate
4341 else
4345 else
4364 else
4369 else
4378 -- For a subtype mark or subtype indication, freeze the subtype
4380 else
4384 Error_Msg_N
4388 -- A special accessibility check is needed for allocators that
4389 -- constrain access discriminants. The level of the type of the
4390 -- expression used to constrain an access discriminant cannot be
4391 -- deeper than the type of the allocator (in contrast to access
4392 -- parameters, where the level of the actual can be arbitrary).
4393 -- We can't use Valid_Conversion to perform this check because
4394 -- in general the type of the allocator is unrelated to the type
4395 -- of the access discriminant.
4400 then
4410 else
4424 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4425 -- check that the level of the type of the created object is not deeper
4426 -- than the level of the allocator's access type, since extensions can
4427 -- now occur at deeper levels than their ancestor types. This is a
4428 -- static accessibility level check; a run-time check is also needed in
4429 -- the case of an initialized allocator with a class-wide argument (see
4430 -- Expand_Allocator_Expression).
4434 then
4435 declare
4438 begin
4443 else
4449 then
4454 E);
4460 -- Do not apply Ada 2005 accessibility checks on a class-wide
4461 -- allocator if the type given in the allocator is a formal
4462 -- type. A run-time check will be performed in the instance.
4472 -- Check for allocation from an empty storage pool
4477 -- If the context is an unchecked conversion, as may happen within an
4478 -- inlined subprogram, the allocator is being resolved with its own
4479 -- anonymous type. In that case, if the target type has a specific
4480 -- storage pool, it must be inherited explicitly by the allocator type.
4484 then
4485 Set_Associated_Storage_Pool
4493 -- Check that an allocator with task parts isn't for a nested access
4494 -- type when restriction No_Task_Hierarchy applies.
4498 then
4502 -- An erroneous allocator may be rewritten as a raise Program_Error
4503 -- statement.
4507 -- An anonymous access discriminant is the definition of a
4508 -- coextension.
4512 N_Discriminant_Specification
4513 then
4514 declare
4518 begin
4519 -- Ada 2012 AI05-0052: If the designated type of the allocator
4520 -- is limited, then the allocator shall not be used to define
4521 -- the value of an access discriminant unless the discriminated
4522 -- type is immutably limited.
4527 then
4528 Error_Msg_N
4534 -- Avoid marking an allocator as a dynamic coextension if it is
4535 -- within a static construct.
4541 -- Cleanup for potential static coextensions
4543 else
4549 -- Report a simple error: if the designated object is a local task,
4550 -- its body has not been seen yet, and its activation will fail an
4551 -- elaboration check.
4558 then
4563 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4564 -- type with a task component on a subpool. This action must raise
4565 -- Program_Error at runtime.
4571 then
4582 ---------------------------
4583 -- Resolve_Arithmetic_Op --
4584 ---------------------------
4586 -- Used for resolving all arithmetic operators except exponentiation
4597 -- We do the resolution using the base type, because intermediate values
4598 -- in expressions always are of the base type, not a subtype of it.
4601 -- Returns True if N is in a context that expects "any real type"
4604 -- Return True iff given type is Integer or universal real/integer
4607 -- Choose type of integer literal in fixed-point operation to conform
4608 -- to available fixed-point type. T is the type of the other operand,
4609 -- which is needed to determine the expected type of N.
4612 -- Set operand type to T if universal
4614 -------------------------------
4615 -- Expected_Type_Is_Any_Real --
4616 -------------------------------
4619 begin
4620 -- N is the expression after "delta" in a fixed_point_definition;
4621 -- see RM-3.5.9(6):
4624 N_Decimal_Fixed_Point_Definition,
4626 -- N is one of the bounds in a real_range_specification;
4627 -- see RM-3.5.7(5):
4629 N_Real_Range_Specification,
4631 -- N is the expression of a delta_constraint;
4632 -- see RM-J.3(3):
4634 N_Delta_Constraint);
4637 -----------------------------
4638 -- Is_Integer_Or_Universal --
4639 -----------------------------
4646 begin
4652 else
4658 then
4669 ----------------------------
4670 -- Set_Mixed_Mode_Operand --
4671 ----------------------------
4677 begin
4680 -- A universal integer literal is resolved as standard integer
4681 -- except in the case of a fixed-point result, where we leave it
4682 -- as universal (to be handled by Exp_Fixd later on)
4686 else
4694 then
4695 -- A universal real can appear in a fixed-type context. We resolve
4696 -- the literal with that context, even though this might raise an
4697 -- exception prematurely (the other operand may be zero).
4704 then
4705 -- Integer arg in mixed-mode operation. Resolve with universal
4706 -- type, in case preference rule must be applied.
4712 then
4713 -- Not a mixed-mode operation, resolve with context
4719 -- N may itself be a mixed-mode operation, so use context type
4726 then
4727 -- Must be (fixed * fixed) operation, operand must have one
4728 -- compatible interpretation.
4736 then
4737 -- C * F(X) in a fixed context, where C is a real literal or a
4738 -- fixed-point expression. F must have either a fixed type
4739 -- interpretation or an integer interpretation, but not both.
4746 else
4753 else
4761 -- Reanalyze the literal with the fixed type of the context. If
4762 -- context is Universal_Fixed, we are within a conversion, leave
4763 -- the literal as a universal real because there is no usable
4764 -- fixed type, and the target of the conversion plays no role in
4765 -- the resolution.
4767 declare
4771 begin
4774 else
4780 then
4782 else
4790 else
4795 ----------------------
4796 -- Set_Operand_Type --
4797 ----------------------
4800 begin
4803 then
4808 -- Start of processing for Resolve_Arithmetic_Op
4810 begin
4815 then
4819 -- Special-case for mixed-mode universal expressions or fixed point type
4820 -- operation: each argument is resolved separately. The same treatment
4821 -- is required if one of the operands of a fixed point operation is
4822 -- universal real, since in this case we don't do a conversion to a
4823 -- specific fixed-point type (instead the expander handles the case).
4825 -- Set the type of the node to its universal interpretation because
4826 -- legality checks on an exponentiation operand need the context.
4831 then
4842 or else
4845 then
4850 -- If context is a fixed type and one operand is integer, the other
4851 -- is resolved with the type of the context.
4856 then
4863 then
4867 else
4872 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4873 -- multiplying operators from being used when the expected type is
4874 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4875 -- some cases where the expected type is actually Any_Real;
4876 -- Expected_Type_Is_Any_Real takes care of that case.
4880 then
4884 N_Unchecked_Type_Conversion)
4885 then
4892 else
4895 and then not
4897 N_Unchecked_Type_Conversion)
4898 then
4899 Error_Msg_N
4904 -- The expected type is "any real type" in contexts like
4906 -- type T is delta <universal_fixed-expression> ...
4908 -- in which case we need to set the type to Universal_Real
4909 -- so that static expression evaluation will work properly.
4913 else
4923 then
4928 -- If no previous errors, this is only possible if one operand is
4929 -- overloaded and the context is universal. Resolve as such.
4934 else
4936 and then
4938 then
4942 -- If the context is Universal_Fixed and the operands are also
4943 -- universal fixed, this is an error, unless there is only one
4944 -- applicable fixed_point type (usually Duration).
4952 else
4957 else
4962 -- If one of the arguments was resolved to a non-universal type.
4963 -- label the result of the operation itself with the same type.
4964 -- Do the same for the universal argument, if any.
4976 -- In SPARK, a multiplication or division with operands of fixed point
4977 -- types shall be qualified or explicitly converted to identify the
4978 -- result type.
4983 and then
4985 then
4986 Check_SPARK_Restriction
4990 -- Set overflow and division checking bit
4997 -- Give warning if explicit division by zero
5001 then
5007 or else
5010 then
5011 -- Specialize the warning message according to the operation.
5012 -- The following warnings are for the case
5017 -- For division, we have two cases, for float division
5018 -- of an unconstrained float type, on a machine where
5019 -- Machine_Overflows is false, we don't get an exception
5020 -- at run-time, but rather an infinity or Nan. The Nan
5021 -- case is pretty obscure, so just warn about infinities.
5025 and then not Machine_Overflows_On_Target
5026 then
5027 Error_Msg_N
5031 -- For all other cases, we get a Constraint_Error
5033 else
5034 Apply_Compile_Time_Constraint_Error
5040 Apply_Compile_Time_Constraint_Error
5045 Apply_Compile_Time_Constraint_Error
5049 -- Division by zero can only happen with division, rem,
5050 -- and mod operations.
5056 -- Otherwise just set the flag to check at run time
5058 else
5063 -- If Restriction No_Implicit_Conditionals is active, then it is
5064 -- violated if either operand can be negative for mod, or for rem
5065 -- if both operands can be negative.
5069 then
5070 declare
5077 -- Set if corresponding operand might be negative
5079 begin
5080 Determine_Range
5084 Determine_Range
5088 -- Check if we will be generating conditionals. There are two
5089 -- cases where that can happen, first for REM, the only case
5090 -- is largest negative integer mod -1, where the division can
5091 -- overflow, but we still have to give the right result. The
5092 -- front end generates a test for this annoying case. Here we
5093 -- just test if both operands can be negative (that's what the
5094 -- expander does, so we match its logic here).
5096 -- The second case is mod where either operand can be negative.
5097 -- In this case, the back end has to generate additional tests.
5100 or else
5102 then
5113 ------------------
5114 -- Resolve_Call --
5115 ------------------
5127 function Same_Or_Aliased_Subprograms
5130 -- Returns True if the subprogram entity S is the same as E or else
5131 -- S is an alias of E.
5133 ---------------------------------
5134 -- Same_Or_Aliased_Subprograms --
5135 ---------------------------------
5137 function Same_Or_Aliased_Subprograms
5140 is
5142 begin
5147 -- Start of processing for Resolve_Call
5149 begin
5150 -- The context imposes a unique interpretation with type Typ on a
5151 -- procedure or function call. Find the entity of the subprogram that
5152 -- yields the expected type, and propagate the corresponding formal
5153 -- constraints on the actuals. The caller has established that an
5154 -- interpretation exists, and emitted an error if not unique.
5156 -- First deal with the case of a call to an access-to-subprogram,
5157 -- dereference made explicit in Analyze_Call.
5163 else
5164 -- Find the interpretation whose type (a subprogram type) has a
5165 -- return type that is compatible with the context. Analysis of
5166 -- the node has established that one exists.
5185 -- If the prefix is not an entity, then resolve it
5191 -- For an indirect call, we always invalidate checks, since we do not
5192 -- know whether the subprogram is local or global. Yes we could do
5193 -- better here, e.g. by knowing that there are no local subprograms,
5194 -- but it does not seem worth the effort. Similarly, we kill all
5195 -- knowledge of current constant values.
5197 Kill_Current_Values;
5199 -- If this is a procedure call which is really an entry call, do
5200 -- the conversion of the procedure call to an entry call. Protected
5201 -- operations use the same circuitry because the name in the call
5202 -- can be an arbitrary expression with special resolution rules.
5207 then
5211 -- Kill checks and constant values, as above for indirect case
5212 -- Who knows what happens when another task is activated?
5214 Kill_Current_Values;
5217 -- Normal subprogram call with name established in Resolve
5223 -- Otherwise we must have the case of an overloaded call
5225 else
5228 -- Initialize Nam to prevent warning (we know it will be assigned
5229 -- in the loop below, but the compiler does not know that).
5249 then
5250 -- The prefix is a parameterless function call that returns an access
5251 -- to subprogram. If parameters are present in the current call, add
5252 -- add an explicit dereference. We use the base type here because
5253 -- within an instance these may be subtypes.
5255 -- The dereference is added either in Analyze_Call or here. Should
5256 -- be consolidated ???
5265 -- Check that a call to Current_Task does not occur in an entry body
5268 declare
5271 begin
5273 loop
5276 -- Exclude calls that occur within the default of a formal
5277 -- parameter of the entry, since those are evaluated outside
5278 -- of the body.
5285 then
5287 Error_Msg_NE
5290 Error_Msg_NE
5302 -- Check that a procedure call does not occur in the context of the
5303 -- entry call statement of a conditional or timed entry call. Note that
5304 -- the case of a call to a subprogram renaming of an entry will also be
5305 -- rejected. The test for N not being an N_Entry_Call_Statement is
5306 -- defensive, covering the possibility that the processing of entry
5307 -- calls might reach this point due to later modifications of the code
5308 -- above.
5313 then
5317 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5318 -- for a procedure_or_entry_call, the procedure_name or
5319 -- procedure_prefix of the procedure_call_statement shall denote
5320 -- an entry renamed by a procedure, or (a view of) a primitive
5321 -- subprogram of a limited interface whose first parameter is
5322 -- a controlling parameter.
5327 then
5328 Error_Msg_N
5333 -- Check that this is not a call to a protected procedure or entry from
5334 -- within a protected function.
5338 -- Freeze the subprogram name if not in a spec-expression. Note that we
5339 -- freeze procedure calls as well as function calls. Procedure calls are
5340 -- not frozen according to the rules (RM 13.14(14)) because it is
5341 -- impossible to have a procedure call to a non-frozen procedure in pure
5342 -- Ada, but in the code that we generate in the expander, this rule
5343 -- needs extending because we can generate procedure calls that need
5344 -- freezing.
5346 -- In Ada 2012, expression functions may be called within pre/post
5347 -- conditions of subsequent functions or expression functions. Such
5348 -- calls do not freeze when they appear within generated bodies, which
5349 -- would place the freeze node in the wrong scope. An expression
5350 -- function is frozen in the usual fashion, by the appearance of a real
5351 -- body, or at the end of a declarative part.
5354 and then
5357 then
5361 -- For a predefined operator, the type of the result is the type imposed
5362 -- by context, except for a predefined operation on universal fixed.
5363 -- Otherwise The type of the call is the type returned by the subprogram
5364 -- being called.
5371 -- If the subprogram returns an array type, and the context requires the
5372 -- component type of that array type, the node is really an indexing of
5373 -- the parameterless call. Resolve as such. A pathological case occurs
5374 -- when the type of the component is an access to the array type. In
5375 -- this case the call is truly ambiguous.
5378 and then
5383 and then
5384 Covers
5387 then
5388 declare
5393 begin
5396 then
5397 Error_Msg_N
5399 else
5405 or else
5407 and then
5409 then
5412 -- Indexed call to a parameterless function
5414 Index_Node :=
5416 Prefix =>
5420 else
5421 -- An Ada 2005 prefixed call to a primitive operation
5422 -- whose first parameter is the prefix. This prefix was
5423 -- prepended to the parameter list, which is actually a
5424 -- list of indexes. Remove the prefix in order to build
5425 -- the proper indexed component.
5427 Index_Node :=
5429 Prefix =>
5432 Parameter_Associations =>
5433 New_List
5438 -- Preserve the parenthesis count of the node
5442 -- Since we are correcting a node classification error made
5443 -- by the parser, we call Replace rather than Rewrite.
5457 else
5461 -- In the case where the call is to an overloaded subprogram, Analyze
5462 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5463 -- such a case Normalize_Actuals needs to be called once more to order
5464 -- the actuals correctly. Otherwise the call will have the ordering
5465 -- given by the last overloaded subprogram whether this is the correct
5466 -- one being called or not.
5473 -- In any case, call is fully resolved now. Reset Overload flag, to
5474 -- prevent subsequent overload resolution if node is analyzed again
5479 -- If we are calling the current subprogram from immediately within its
5480 -- body, then that is the case where we can sometimes detect cases of
5481 -- infinite recursion statically. Do not try this in case restriction
5482 -- No_Recursion is in effect anyway, and do it only for source calls.
5487 -- Issue warning for possible infinite recursion in the absence
5488 -- of the No_Recursion restriction.
5493 then
5494 -- Here we detected and flagged an infinite recursion, so we do
5495 -- not need to test the case below for further warnings. Also we
5496 -- are all done if we now have a raise SE node.
5502 -- If call is to immediately containing subprogram, then check for
5503 -- the case of a possible run-time detectable infinite recursion.
5505 else
5509 -- Although in general case, recursion is not statically
5510 -- checkable, the case of calling an immediately containing
5511 -- subprogram is easy to catch.
5515 -- If the recursive call is to a parameterless subprogram,
5516 -- then even if we can't statically detect infinite
5517 -- recursion, this is pretty suspicious, and we output a
5518 -- warning. Furthermore, we will try later to detect some
5519 -- cases here at run time by expanding checking code (see
5520 -- Detect_Infinite_Recursion in package Exp_Ch6).
5522 -- If the recursive call is within a handler, do not emit a
5523 -- warning, because this is a common idiom: loop until input
5524 -- is correct, catch illegal input in handler and restart.
5530 then
5531 -- For the case of a procedure call. We give the message
5532 -- only if the call is the first statement in a sequence
5533 -- of statements, or if all previous statements are
5534 -- simple assignments. This is simply a heuristic to
5535 -- decrease false positives, without losing too many good
5536 -- warnings. The idea is that these previous statements
5537 -- may affect global variables the procedure depends on.
5538 -- We also exclude raise statements, that may arise from
5539 -- constraint checks and are probably unrelated to the
5540 -- intended control flow.
5544 then
5545 declare
5547 begin
5551 N_Assignment_Statement,
5552 N_Raise_Constraint_Error)
5553 then
5562 -- Do not give warning if we are in a conditional context
5564 declare
5566 begin
5572 then
5577 -- Here warning is to be issued
5580 Error_Msg_N
5582 Error_Msg_N
5594 -- Check obsolescent reference to Ada.Characters.Handling subprogram
5598 -- If subprogram name is a predefined operator, it was given in
5599 -- functional notation. Replace call node with operator node, so
5600 -- that actuals can be resolved appropriately.
5608 then
5614 -- Create a transient scope if the resulting type requires it
5616 -- There are several notable exceptions:
5618 -- a) In init procs, the transient scope overhead is not needed, and is
5619 -- even incorrect when the call is a nested initialization call for a
5620 -- component whose expansion may generate adjust calls. However, if the
5621 -- call is some other procedure call within an initialization procedure
5622 -- (for example a call to Create_Task in the init_proc of the task
5623 -- run-time record) a transient scope must be created around this call.
5625 -- b) Enumeration literal pseudo-calls need no transient scope
5627 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
5628 -- functions) do not use the secondary stack even though the return
5629 -- type may be unconstrained.
5631 -- d) Calls to a build-in-place function, since such functions may
5632 -- allocate their result directly in a target object, and cases where
5633 -- the result does get allocated in the secondary stack are checked for
5634 -- within the specialized Exp_Ch6 procedures for expanding those
5635 -- build-in-place calls.
5637 -- e) If the subprogram is marked Inline_Always, then even if it returns
5638 -- an unconstrained type the call does not require use of the secondary
5639 -- stack. However, inlining will only take place if the body to inline
5640 -- is already present. It may not be available if e.g. the subprogram is
5641 -- declared in a child instance.
5643 -- If this is an initialization call for a type whose construction
5644 -- uses the secondary stack, and it is not a nested call to initialize
5645 -- a component, we do need to create a transient scope for it. We
5646 -- check for this by traversing the type in Check_Initialization_Call.
5652 and then not Debug_Flag_Dot_K
5653 then
5660 and then Debug_Flag_Dot_K
5661 then
5667 then
5670 elsif Full_Expander_Active
5673 and then
5675 or else
5677 then
5680 -- If the call appears within the bounds of a loop, it will
5681 -- be rewritten and reanalyzed, nothing left to do here.
5688 and then not Within_Init_Proc
5689 then
5693 -- A protected function cannot be called within the definition of the
5694 -- enclosing protected type.
5699 then
5700 Error_Msg_NE
5704 -- Propagate interpretation to actuals, and add default expressions
5705 -- where needed.
5710 -- Overloaded literals are rewritten as function calls, for purpose of
5711 -- resolution. After resolution, we can replace the call with the
5712 -- literal itself.
5718 -- Avoid validation, since it is a static function call
5724 -- If the subprogram is not global, then kill all saved values and
5725 -- checks. This is a bit conservative, since in many cases we could do
5726 -- better, but it is not worth the effort. Similarly, we kill constant
5727 -- values. However we do not need to do this for internal entities
5728 -- (unless they are inherited user-defined subprograms), since they
5729 -- are not in the business of molesting local values.
5731 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5732 -- kill all checks and values for calls to global subprograms. This
5733 -- takes care of the case where an access to a local subprogram is
5734 -- taken, and could be passed directly or indirectly and then called
5735 -- from almost any context.
5737 -- Note: we do not do this step till after resolving the actuals. That
5738 -- way we still take advantage of the current value information while
5739 -- scanning the actuals.
5741 -- We suppress killing values if we are processing the nodes associated
5742 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5743 -- type kills all the values as part of analyzing the code that
5744 -- initializes the dispatch tables.
5748 or else Suppress_Value_Tracking_On_Call
5753 then
5754 Kill_Current_Values;
5757 -- If we are warning about unread OUT parameters, this is the place to
5758 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5759 -- after the above call to Kill_Current_Values (since that call clears
5760 -- the Last_Assignment field of all local variables).
5765 then
5766 declare
5770 begin
5780 then
5790 -- If the subprogram is a primitive operation, check whether or not
5791 -- it is a correct dispatching call.
5795 then
5800 and then not In_Instance
5801 then
5805 -- If this is a dispatching call, generate the appropriate reference,
5806 -- for better source navigation in GPS.
5810 then
5813 -- Normal case, not a dispatching call: generate a call reference
5815 else
5823 -- Check for violation of restriction No_Specific_Termination_Handlers
5824 -- and warn on a potentially blocking call to Abort_Task.
5828 or else
5830 then
5837 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
5838 -- timing event violates restriction No_Relative_Delay (AI-0211). We
5839 -- need to check the second argument to determine whether it is an
5840 -- absolute or relative timing event.
5845 then
5849 -- Issue an error for a call to an eliminated subprogram. This routine
5850 -- will not perform the check if the call appears within a default
5851 -- expression.
5855 -- In formal mode, the primitive operations of a tagged type or type
5856 -- extension do not include functions that return the tagged type.
5858 -- Commented out as the call to Is_Inherited_Operation_For_Type may
5859 -- cause an error because the type entity of the parent node of
5860 -- Entity (Name (N) may not be set. ???
5861 -- So why not just add a guard ???
5863 -- if Nkind (N) = N_Function_Call
5864 -- and then Is_Tagged_Type (Etype (N))
5865 -- and then Is_Entity_Name (Name (N))
5866 -- and then Is_Inherited_Operation_For_Type
5867 -- (Entity (Name (N)), Etype (N))
5868 -- then
5869 -- Check_SPARK_Restriction ("function not inherited", N);
5870 -- end if;
5872 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
5873 -- class-wide and the call dispatches on result in a context that does
5874 -- not provide a tag, the call raises Program_Error.
5877 and then In_Instance
5882 then
5883 -- Verify that none of the formals are controlling
5885 declare
5889 begin
5910 -- Check the dimensions of the actuals in the call. For function calls,
5911 -- propagate the dimensions from the returned type to N.
5915 -- All done, evaluate call and deal with elaboration issues
5922 -----------------------------
5923 -- Resolve_Case_Expression --
5924 -----------------------------
5929 begin
5940 -------------------------------
5941 -- Resolve_Character_Literal --
5942 -------------------------------
5948 begin
5949 -- Verify that the character does belong to the type of the context
5954 -- Wide_Wide_Character literals must always be defined, since the set
5955 -- of wide wide character literals is complete, i.e. if a character
5956 -- literal is accepted by the parser, then it is OK for wide wide
5957 -- character (out of range character literals are rejected).
5962 -- Always accept character literal for type Any_Character, which
5963 -- occurs in error situations and in comparisons of literals, both
5964 -- of which should accept all literals.
5969 -- For Standard.Character or a type derived from it, check that the
5970 -- literal is in range.
5977 -- For Standard.Wide_Character or a type derived from it, check that the
5978 -- literal is in range.
5985 -- For Standard.Wide_Wide_Character or a type derived from it, we
5986 -- know the literal is in range, since the parser checked!
5991 -- If the entity is already set, this has already been resolved in a
5992 -- generic context, or comes from expansion. Nothing else to do.
5997 -- Otherwise we have a user defined character type, and we can use the
5998 -- standard visibility mechanisms to locate the referenced entity.
6000 else
6013 -- If we fall through, then the literal does not match any of the
6014 -- entries of the enumeration type. This isn't just a constraint error
6015 -- situation, it is an illegality (see RM 4.2).
6017 Error_Msg_NE
6021 ---------------------------
6022 -- Resolve_Comparison_Op --
6023 ---------------------------
6025 -- Context requires a boolean type, and plays no role in resolution.
6026 -- Processing identical to that for equality operators. The result type is
6027 -- the base type, which matters when pathological subtypes of booleans with
6028 -- limited ranges are used.
6035 begin
6036 -- If this is an intrinsic operation which is not predefined, use the
6037 -- types of its declared arguments to resolve the possibly overloaded
6038 -- operands. Otherwise the operands are unambiguous and specify the
6039 -- expected type.
6044 else
6055 -- Skip remaining processing if already set to Any_Type
6061 -- Deal with other error cases
6065 T = Any_Character
6066 then
6069 else
6077 -- Resolve the operands if types OK
6086 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6087 -- types or array types except String.
6090 Check_SPARK_Restriction
6095 then
6096 Check_SPARK_Restriction
6100 -- Check comparison on unordered enumeration
6106 -- Evaluate the relation (note we do this after the above check since
6107 -- this Eval call may change N to True/False.
6113 -----------------------------------------
6114 -- Resolve_Discrete_Subtype_Indication --
6115 -----------------------------------------
6117 procedure Resolve_Discrete_Subtype_Indication
6120 is
6124 begin
6132 else
6142 Error_Msg_NE
6145 -- Rewrite the constraint as a range of Typ
6146 -- to allow compilation to proceed further.
6158 else
6162 -- Additionally, we must check that the bounds are compatible
6163 -- with the given subtype, which might be different from the
6164 -- type of the context.
6168 -- ??? If the above check statically detects a Constraint_Error
6169 -- it replaces the offending bound(s) of the range R with a
6170 -- Constraint_Error node. When the itype which uses these bounds
6171 -- is frozen the resulting call to Duplicate_Subexpr generates
6172 -- a new temporary for the bounds.
6174 -- Unfortunately there are other itypes that are also made depend
6175 -- on these bounds, so when Duplicate_Subexpr is called they get
6176 -- a forward reference to the newly created temporaries and Gigi
6177 -- aborts on such forward references. This is probably sign of a
6178 -- more fundamental problem somewhere else in either the order of
6179 -- itype freezing or the way certain itypes are constructed.
6181 -- To get around this problem we call Remove_Side_Effects right
6182 -- away if either bounds of R are a Constraint_Error.
6184 declare
6188 begin
6204 -------------------------
6205 -- Resolve_Entity_Name --
6206 -------------------------
6208 -- Used to resolve identifiers and expanded names
6213 begin
6214 -- If garbage from errors, set to Any_Type and return
6221 -- Replace named numbers by corresponding literals. Note that this is
6222 -- the one case where Resolve_Entity_Name must reset the Etype, since
6223 -- it is currently marked as universal.
6233 -- For enumeration literals, we need to make sure that a proper style
6234 -- check is done, since such literals are overloaded, and thus we did
6235 -- not do a style check during the first phase of analysis.
6241 -- Case of subtype name appearing as an operand in expression
6245 -- Allow use of subtype if it is a concurrent type where we are
6246 -- currently inside the body. This will eventually be expanded into a
6247 -- call to Self (for tasks) or _object (for protected objects). Any
6248 -- other use of a subtype is invalid.
6252 then
6255 -- Any other use is an error
6257 else
6258 Error_Msg_N
6262 -- Check discriminant use if entity is discriminant in current scope,
6263 -- i.e. discriminant of record or concurrent type currently being
6264 -- analyzed. Uses in corresponding body are unrestricted.
6269 then
6272 -- A parameterless generic function cannot appear in a context that
6273 -- requires resolution.
6284 then
6287 -- In all other cases, just do the possible static evaluation
6289 else
6290 -- A deferred constant that appears in an expression must have a
6291 -- completion, unless it has been removed by in-place expansion of
6292 -- an aggregate.
6298 and then not In_Spec_Expression
6300 then
6304 then
6306 else
6307 Error_Msg_N (
6316 -------------------
6317 -- Resolve_Entry --
6318 -------------------
6330 -- If the bounds of the entry family being called depend on task
6331 -- discriminants, build a new index subtype where a discriminant is
6332 -- replaced with the value of the discriminant of the target task.
6333 -- The target task is the prefix of the entry name in the call.
6335 -----------------------
6336 -- Actual_Index_Type --
6337 -----------------------
6347 -- If the bound is given by a discriminant, replace with a reference
6348 -- to the discriminant of the same name in the target task. If the
6349 -- entry name is the target of a requeue statement and the entry is
6350 -- in the current protected object, the bound to be used is the
6351 -- discriminal of the object (see Apply_Range_Checks for details of
6352 -- the transformation).
6354 -----------------------------
6355 -- Actual_Discriminant_Ref --
6356 -----------------------------
6362 begin
6367 then
6373 then
6374 -- Note: here Bound denotes a discriminant of the corresponding
6375 -- record type tskV, whose discriminal is a formal of the
6376 -- init-proc tskVIP. What we want is the body discriminal,
6377 -- which is associated to the discriminant of the original
6378 -- concurrent type tsk.
6380 return New_Occurrence_Of
6383 else
6384 Ref :=
6394 -- Start of processing for Actual_Index_Type
6396 begin
6399 then
6402 else
6416 -- Start of processing of Resolve_Entry
6418 begin
6419 -- Find name of entry being called, and resolve prefix of name with its
6420 -- own type. The prefix can be overloaded, and the name and signature of
6421 -- the entry must be taken into account.
6425 -- Case of dealing with entry family within the current tasks
6429 else
6435 -- Entry call to an entry (or entry family) in the current task. This
6436 -- is legal even though the task will deadlock. Rewrite as call to
6437 -- current task.
6439 -- This can also be a call to an entry in an enclosing task. If this
6440 -- is a single task, we have to retrieve its name, because the scope
6441 -- of the entry is the task type, not the object. If the enclosing
6442 -- task is a task type, the identity of the task is given by its own
6443 -- self variable.
6445 -- Finally this can be a requeue on an entry of the same task or
6446 -- protected object.
6453 then
6454 -- S is an enclosing task or protected object. The concurrent
6455 -- declaration has been converted into a type declaration, and
6456 -- the object itself has an object declaration that follows
6457 -- the type in the same declarative part.
6469 -- Call to current task. Will be transformed into call to Self
6476 New_N :=
6479 Selector_Name =>
6486 then
6487 -- Use the entry name (which must be unique at this point) to find
6488 -- the prefix that returns the corresponding task/protected type.
6490 declare
6496 begin
6518 -- Up to this point the expression could have been the actual in a
6519 -- simple entry call, and be given by a named association.
6523 else
6529 ------------------------
6530 -- Resolve_Entry_Call --
6531 ------------------------
6543 begin
6544 -- We kill all checks here, because it does not seem worth the effort to
6545 -- do anything better, an entry call is a big operation.
6547 Kill_All_Checks;
6549 -- Processing of the name is similar for entry calls and protected
6550 -- operation calls. Once the entity is determined, we can complete
6551 -- the resolution of the actuals.
6553 -- The selector may be overloaded, in the case of a protected object
6554 -- with overloaded functions. The type of the context is used for
6555 -- resolution.
6560 then
6561 declare
6565 begin
6584 -- Simple entry call
6592 -- Call to member of entry family
6599 -- We cannot in general check the maximum depth of protected entry calls
6600 -- at compile time. But we can tell that any protected entry call at all
6601 -- violates a specified nesting depth of zero.
6607 -- Use context type to disambiguate a protected function that can be
6608 -- called without actuals and that returns an array type, and where the
6609 -- argument list may be an indexing of the returned value.
6614 and then
6620 and then
6621 Covers
6624 then
6625 declare
6628 begin
6629 Index_Node :=
6631 Prefix =>
6635 -- Since we are correcting a node classification error made by the
6636 -- parser, we call Replace rather than Rewrite.
6649 then
6650 -- Rewrite as call to the precondition wrapper, adding the task
6651 -- object to the list of actuals. If the call is to a member of an
6652 -- entry family, include the index as well.
6654 declare
6658 begin
6667 New_Call :=
6669 Name =>
6678 -- The operation name may have been overloaded. Order the actuals
6679 -- according to the formals of the resolved entity, and set the return
6680 -- type to that of the operation.
6691 -- Create a call reference to the entry
6699 -- Verify that a procedure call cannot masquerade as an entry
6700 -- call where an entry call is expected.
6705 then
6710 then
6715 then
6720 -- After resolution, entry calls and protected procedure calls are
6721 -- changed into entry calls, for expansion. The structure of the node
6722 -- does not change, so it can safely be done in place. Protected
6723 -- function calls must keep their structure because they are
6724 -- subexpressions.
6728 -- A protected operation that is not a function may modify the
6729 -- corresponding object, and cannot apply to a constant. If this
6730 -- is an internal call, the prefix is the type itself.
6736 then
6737 Error_Msg_N
6739 Entry_Name);
6753 -- Protected functions can return on the secondary stack, in which
6754 -- case we must trigger the transient scope mechanism.
6756 elsif Full_Expander_Active
6758 then
6763 -------------------------
6764 -- Resolve_Equality_Op --
6765 -------------------------
6767 -- Both arguments must have the same type, and the boolean context does
6768 -- not participate in the resolution. The first pass verifies that the
6769 -- interpretation is not ambiguous, and the type of the left argument is
6770 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
6771 -- are strings or aggregates, allocators, or Null, they are ambiguous even
6772 -- though they carry a single (universal) type. Diagnose this case here.
6780 -- The resolution rule for if expressions requires that each such must
6781 -- have a unique type. This means that if several dependent expressions
6782 -- are of a non-null anonymous access type, and the context does not
6783 -- impose an expected type (as can be the case in an equality operation)
6784 -- the expression must be rejected.
6787 -- In the case of allocators, make a last-ditch attempt to find a single
6788 -- access type with the right designated type. This is semantically
6789 -- dubious, and of no interest to any real code, but c48008a makes it
6790 -- all worthwhile.
6792 -------------------------
6793 -- Check_If_Expression --
6794 -------------------------
6800 begin
6807 then
6813 -----------------------------
6814 -- Find_Unique_Access_Type --
6815 -----------------------------
6822 begin
6827 else
6839 then
6852 -- Start of processing for Resolve_Equality_Op
6854 begin
6865 T = Any_Character
6866 then
6869 else
6878 then
6887 -- If expressions must have a single type, and if the context does
6888 -- not impose one the dependent expressions cannot be anonymous
6889 -- access types.
6891 -- Why no similar processing for case expressions???
6895 E_Anonymous_Access_Subprogram_Type)
6897 E_Anonymous_Access_Subprogram_Type)
6898 then
6906 -- In SPARK, equality operators = and /= for array types other than
6907 -- String are only defined when, for each index position, the
6908 -- operands have equal static bounds.
6912 -- Protect call to Matching_Static_Array_Bounds to avoid costly
6913 -- operation if not needed.
6921 then
6922 Check_SPARK_Restriction
6927 -- If the unique type is a class-wide type then it will be expanded
6928 -- into a dispatching call to the predefined primitive. Therefore we
6929 -- check here for potential violation of such restriction.
6935 if Warn_On_Redundant_Constructs
6940 then
6941 Error_Msg_N -- CODEFIX
6950 -- If this is an inequality, it may be the implicit inequality
6951 -- created for a user-defined operation, in which case the corres-
6952 -- ponding equality operation is not intrinsic, and the operation
6953 -- cannot be constant-folded. Else fold.
6958 or else Is_Intrinsic_Subprogram
6960 then
6966 then
6970 -- Ada 2005: If one operand is an anonymous access type, convert the
6971 -- other operand to it, to ensure that the underlying types match in
6972 -- the back-end. Same for access_to_subprogram, and the conversion
6973 -- verifies that the types are subtype conformant.
6975 -- We apply the same conversion in the case one of the operands is a
6976 -- private subtype of the type of the other.
6978 -- Why the Expander_Active test here ???
6980 if Full_Expander_Active
6981 and then
6983 E_Anonymous_Access_Subprogram_Type)
6985 then
7005 ----------------------------------
7006 -- Resolve_Explicit_Dereference --
7007 ----------------------------------
7015 -- The candidate prefix type, if overloaded
7020 begin
7026 -- Use the context type to select the prefix that has the correct
7027 -- designated type. Keep the first match, which will be the inner-
7028 -- most.
7035 then
7040 -- Remove access types that do not match, but preserve access
7041 -- to subprogram interpretations, in case a further dereference
7042 -- is needed (see below).
7055 else
7056 -- If no interpretation covers the designated type of the prefix,
7057 -- this is the pathological case where not all implementations of
7058 -- the prefix allow the interpretation of the node as a call. Now
7059 -- that the expected type is known, Remove other interpretations
7060 -- from prefix, rewrite it as a call, and resolve again, so that
7061 -- the proper call node is generated.
7072 New_N :=
7074 Name =>
7085 -- If not overloaded, resolve P with its own type
7087 else
7095 -- If the designated type is a packed unconstrained array type, and the
7096 -- explicit dereference is not in the context of an attribute reference,
7097 -- then we must compute and set the actual subtype, since it is needed
7098 -- by Gigi. The reason we exclude the attribute case is that this is
7099 -- handled fine by Gigi, and in fact we use such attributes to build the
7100 -- actual subtype. We also exclude generated code (which builds actual
7101 -- subtypes directly if they are needed).
7108 then
7112 -- Note: No Eval processing is required for an explicit dereference,
7113 -- because such a name can never be static.
7117 -------------------------------------
7118 -- Resolve_Expression_With_Actions --
7119 -------------------------------------
7122 begin
7126 ---------------------------
7127 -- Resolve_If_Expression --
7128 ---------------------------
7137 begin
7142 -- When the "then" expression is of a scalar subtype different from the
7143 -- result subtype, then insert a conversion to ensure the generation of
7144 -- a constraint check. The same is done for the else part below, again
7145 -- comparing subtypes rather than base types.
7149 then
7154 -- If ELSE expression present, just resolve using the determined type
7162 then
7167 -- If no ELSE expression is present, root type must be Standard.Boolean
7168 -- and we provide a Standard.True result converted to the appropriate
7169 -- Boolean type (in case it is a derived boolean type).
7172 Else_Expr :=
7177 else
7186 -------------------------------
7187 -- Resolve_Indexed_Component --
7188 -------------------------------
7196 begin
7199 -- Use the context type to select the prefix that yields the correct
7200 -- component type.
7202 declare
7209 begin
7216 and then
7217 Covers
7220 then
7229 else
7235 else
7246 else
7253 -- If prefix is access type, dereference to get real array type.
7254 -- Note: we do not apply an access check because the expander always
7255 -- introduces an explicit dereference, and the check will happen there.
7261 -- If name was overloaded, set component type correctly now
7262 -- If a misplaced call to an entry family (which has no index types)
7263 -- return. Error will be diagnosed from calling context.
7267 else
7274 -- The prefix may have resolved to a string literal, in which case its
7275 -- etype has a special representation. This is only possible currently
7276 -- if the prefix is a static concatenation, written in functional
7277 -- notation.
7282 else
7289 else
7300 -- Do not generate the warning on suspicious index if we are analyzing
7301 -- package Ada.Tags; otherwise we will report the warning with the
7302 -- Prims_Ptr field of the dispatch table.
7305 or else not
7307 Ada_Tags)
7308 then
7313 -- If the array type is atomic, and is packed, and we are in a left side
7314 -- context, then this is worth a warning, since we have a situation
7315 -- where the access to the component may cause extra read/writes of
7316 -- the atomic array object, which could be considered unexpected.
7324 then
7332 -----------------------------
7333 -- Resolve_Integer_Literal --
7334 -----------------------------
7337 begin
7342 --------------------------------
7343 -- Resolve_Intrinsic_Operator --
7344 --------------------------------
7354 -- If the operand is a literal, it cannot be the expression in a
7355 -- conversion. Use a qualified expression instead.
7360 begin
7362 Res :=
7368 else
7375 -- Start of processing for Resolve_Intrinsic_Operator
7377 begin
7378 -- We must preserve the original entity in a generic setting, so that
7379 -- the legality of the operation can be verified in an instance.
7394 -- If the result or operand types are private, rewrite with unchecked
7395 -- conversions on the operands and the result, to expose the proper
7396 -- underlying numeric type.
7401 then
7403 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
7404 -- What on earth is this commented out fragment of code???
7408 else
7429 then
7430 -- Add explicit conversion where needed, and save interpretations in
7431 -- case operands are overloaded. If the context is a VMS operation,
7432 -- assert that the conversion is legal (the operands have the proper
7433 -- types to select the VMS intrinsic). Note that in rare cases the
7434 -- VMS operators may be visible, but the default System is being used
7435 -- and Address is a private type.
7446 else
7456 else
7466 else
7471 --------------------------------------
7472 -- Resolve_Intrinsic_Unary_Operator --
7473 --------------------------------------
7475 procedure Resolve_Intrinsic_Unary_Operator
7478 is
7483 begin
7502 else
7507 ------------------------
7508 -- Resolve_Logical_Op --
7509 ------------------------
7514 begin
7517 -- Predefined operations on scalar types yield the base type. On the
7518 -- other hand, logical operations on arrays yield the type of the
7519 -- arguments (and the context).
7523 else
7527 -- OK if this is a VMS-specific intrinsic operation
7532 -- The following test is required because the operands of the operation
7533 -- may be literals, in which case the resulting type appears to be
7534 -- compatible with a signed integer type, when in fact it is compatible
7535 -- only with modular types. If the context itself is universal, the
7536 -- operation is illegal.
7544 Error_Msg_N
7552 then
7556 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
7557 -- is active and the result type is standard Boolean (do not mess with
7558 -- ops that return a nonstandard Boolean type, because something strange
7559 -- is going on).
7561 -- Note: you might expect this replacement to be done during expansion,
7562 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
7563 -- is used, no part of the right operand of an "and" or "or" operator
7564 -- should be executed if the left operand would short-circuit the
7565 -- evaluation of the corresponding "and then" or "or else". If we left
7566 -- the replacement to expansion time, then run-time checks associated
7567 -- with such operands would be evaluated unconditionally, due to being
7568 -- before the condition prior to the rewriting as short-circuit forms
7569 -- during expansion.
7571 if Short_Circuit_And_Or
7574 then
7582 -- Case of OR changed to OR ELSE
7584 else
7592 -- Return now, since analysis of the rewritten ops will take care of
7593 -- other reference bookkeeping and expression folding.
7608 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
7609 -- only when both operands have same static lower and higher bounds. Of
7610 -- course the types have to match, so only check if operands are
7611 -- compatible and the node itself has no errors.
7615 then
7616 declare
7620 begin
7621 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7622 -- operation if not needed.
7629 then
7630 Check_SPARK_Restriction
7637 ---------------------------
7638 -- Resolve_Membership_Op --
7639 ---------------------------
7641 -- The context can only be a boolean type, and does not determine the
7642 -- arguments. Arguments should be unambiguous, but the preference rule for
7643 -- universal types applies.
7653 -- Analysis has determined a unique type for the left operand. Use it to
7654 -- resolve the disjuncts.
7656 ----------------------------
7657 -- Resolve_Set_Membership --
7658 ----------------------------
7664 begin
7670 -- Alternative is an expression, a range
7671 -- or a subtype mark.
7675 then
7682 -- Check for duplicates for discrete case
7685 declare
7694 begin
7695 -- Loop checking duplicates. This is quadratic, but giant sets
7696 -- are unlikely in this context so it's a reasonable choice.
7703 N_Character_Literal)
7705 then
7723 -- Start of processing for Resolve_Membership_Op
7725 begin
7731 Resolve_Set_Membership;
7735 and then
7737 or else
7740 then
7743 -- Ada 2005 (AI-251): Support the following case:
7745 -- type I is interface;
7746 -- type T is tagged ...
7748 -- function Test (O : I'Class) is
7749 -- begin
7750 -- return O in T'Class.
7751 -- end Test;
7753 -- In this case we have nothing else to do. The membership test will be
7754 -- done at run time.
7761 then
7763 else
7767 -- If mixed-mode operations are present and operands are all literal,
7768 -- the only interpretation involves Duration, which is probably not
7769 -- the intention of the programmer.
7784 then
7790 else
7798 ------------------
7799 -- Resolve_Null --
7800 ------------------
7805 begin
7806 -- Handle restriction against anonymous null access values This
7807 -- restriction can be turned off using -gnatdj.
7809 -- Ada 2005 (AI-231): Remove restriction
7812 and then not Debug_Flag_J
7815 then
7816 -- In the common case of a call which uses an explicitly null value
7817 -- for an access parameter, give specialized error message.
7820 Error_Msg_N
7823 -- Standard message for all other cases (are there any?)
7825 else
7826 Error_Msg_N
7831 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
7832 -- assignment to a null-excluding object
7837 then
7839 Insert_Action
7844 else
7851 -- In a distributed context, null for a remote access to subprogram may
7852 -- need to be replaced with a special record aggregate. In this case,
7853 -- return after having done the transformation.
7858 then
7862 -- The null literal takes its type from the context
7867 -----------------------
7868 -- Resolve_Op_Concat --
7869 -----------------------
7873 -- We wish to avoid deep recursion, because concatenations are often
7874 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
7875 -- operands nonrecursively until we find something that is not a simple
7876 -- concatenation (A in this case). We resolve that, and then walk back
7877 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
7878 -- to do the rest of the work at each level. The Parent pointers allow
7879 -- us to avoid recursion, and thus avoid running out of memory. See also
7880 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
7885 begin
7886 -- The following code is equivalent to:
7888 -- Resolve_Op_Concat_First (NN, Typ);
7889 -- Resolve_Op_Concat_Arg (N, ...);
7890 -- Resolve_Op_Concat_Rest (N, Typ);
7892 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
7893 -- operand is a concatenation.
7895 -- Walk down left operands
7897 loop
7906 -- Now (given the above example) NN is A&B and Op1 is A
7908 -- First resolve Op1 ...
7912 -- ... then walk NN back up until we reach N (where we started), calling
7913 -- Resolve_Op_Concat_Rest along the way.
7915 loop
7922 Check_SPARK_Restriction
7927 ---------------------------
7928 -- Resolve_Op_Concat_Arg --
7929 ---------------------------
7931 procedure Resolve_Op_Concat_Arg
7936 is
7940 begin
7942 if Is_Comp
7946 then
7948 else
7952 -- If both Array & Array and Array & Component are visible, there is a
7953 -- potential ambiguity that must be reported.
7958 then
7962 -- If the operation is user-defined and not overloaded use its
7963 -- profile. The operation may be a renaming, in which case it has
7964 -- been rewritten, and we want the original profile.
7969 then
7971 Etype
7975 -- Otherwise an aggregate may match both the array type and the
7976 -- component type.
7978 else
7983 else
7987 then
7988 declare
7993 begin
7998 -- Special-case the error message when the overloading is
7999 -- caused by a function that yields an array and can be
8000 -- called without parameters.
8005 Error_Msg_NE
8007 Error_Msg_NE
8011 else
8019 or else
8021 then
8022 Error_Msg_N -- CODEFIX
8040 else
8045 else
8049 -- Concatenation is restricted in SPARK: each operand must be either a
8050 -- string literal, the name of a string constant, a static character or
8051 -- string expression, or another concatenation. Arg cannot be a
8052 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
8053 -- separately on each final operand, past concatenation operations.
8057 Check_SPARK_Restriction
8065 then
8066 Check_SPARK_Restriction
8070 -- Do not issue error on an operand that is neither a character nor a
8071 -- string, as the error is issued in Resolve_Op_Concat.
8073 else
8080 -----------------------------
8081 -- Resolve_Op_Concat_First --
8082 -----------------------------
8089 begin
8090 -- The parser folds an enormous sequence of concatenations of string
8091 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
8092 -- in the right operand. If the expression resolves to a predefined "&"
8093 -- operator, all is well. Otherwise, the parser's folding is wrong, so
8094 -- we give an error. See P_Simple_Expression in Par.Ch4.
8099 then
8114 ----------------------------
8115 -- Resolve_Op_Concat_Rest --
8116 ----------------------------
8122 begin
8131 -- If this is not a static concatenation, but the result is a string
8132 -- type (and not an array of strings) ensure that static string operands
8133 -- have their subtypes properly constructed.
8137 then
8143 ----------------------
8144 -- Resolve_Op_Expon --
8145 ----------------------
8150 begin
8151 -- Catch attempts to do fixed-point exponentiation with universal
8152 -- operands, which is a case where the illegality is not caught during
8153 -- normal operator analysis.
8163 then
8172 then
8179 then
8183 -- We do the resolution using the base type, because intermediate values
8184 -- in expressions always are of the base type, not a subtype of it.
8198 -- Evaluate the exponentiation operator for dimensioned type
8201 else
8205 -- Set overflow checking bit. Much cleverer code needed here eventually
8206 -- and perhaps the Resolve routines should be separated for the various
8207 -- arithmetic operations, since they will need different processing. ???
8216 --------------------
8217 -- Resolve_Op_Not --
8218 --------------------
8224 -- This function determines if the parent node is a boolean operator or
8225 -- operation (comparison op, membership test, or short circuit form) and
8226 -- the not in question is the left operand of this operation. Note that
8227 -- if the not is in parens, then false is returned.
8229 -----------------------
8230 -- Parent_Is_Boolean --
8231 -----------------------
8234 begin
8238 else
8240 when N_Op_And |
8241 N_Op_Eq |
8242 N_Op_Ge |
8243 N_Op_Gt |
8244 N_Op_Le |
8245 N_Op_Lt |
8246 N_Op_Ne |
8247 N_Op_Or |
8248 N_Op_Xor |
8249 N_In |
8250 N_Not_In |
8251 N_And_Then |
8252 N_Or_Else =>
8262 -- Start of processing for Resolve_Op_Not
8264 begin
8265 -- Predefined operations on scalar types yield the base type. On the
8266 -- other hand, logical operations on arrays yield the type of the
8267 -- arguments (and the context).
8271 else
8278 -- Straightforward case of incorrect arguments
8285 -- Special case of probable missing parens
8289 Error_Msg_N
8292 else
8293 Error_Msg_N
8300 -- OK resolution of NOT
8302 else
8303 -- Warn if non-boolean types involved. This is a case like not a < b
8304 -- where a and b are modular, where we will get (not a) < b and most
8305 -- likely not (a < b) was intended.
8307 if Warn_On_Questionable_Missing_Parens
8309 and then Parent_Is_Boolean
8310 then
8314 -- Warn on double negation if checking redundant constructs
8316 if Warn_On_Redundant_Constructs
8321 then
8325 -- Complete resolution and evaluation of NOT
8335 -----------------------------
8336 -- Resolve_Operator_Symbol --
8337 -----------------------------
8339 -- Nothing to be done, all resolved already
8345 begin
8349 ----------------------------------
8350 -- Resolve_Qualified_Expression --
8351 ----------------------------------
8359 begin
8362 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8363 -- operation if not needed.
8370 then
8371 Check_SPARK_Restriction
8375 -- A qualified expression requires an exact match of the type, class-
8376 -- wide matching is not allowed. However, if the qualifying type is
8377 -- specific and the expression has a class-wide type, it may still be
8378 -- okay, since it can be the result of the expansion of a call to a
8379 -- dispatching function, so we also have to check class-wideness of the
8380 -- type of the expression's original node.
8383 or else
8387 then
8391 -- If the target type is unconstrained, then we reset the type of the
8392 -- result from the type of the expression. For other cases, the actual
8393 -- subtype of the expression is the target type.
8397 then
8405 -------------------
8406 -- Resolve_Range --
8407 -------------------
8414 -- Returns True if N is of the form X'First .. X'Last where X is the
8415 -- same entity for both attributes.
8417 --------------------
8418 -- First_Last_Ref --
8419 --------------------
8425 begin
8430 then
8431 declare
8434 begin
8438 then
8447 -- Start of processing for Resolve_Range
8449 begin
8454 -- Check for inappropriate range on unordered enumeration type
8458 -- Exclude X'First .. X'Last if X is the same entity for both
8460 and then not First_Last_Ref
8461 then
8468 -- We have to check the bounds for being within the base range as
8469 -- required for a non-static context. Normally this is automatic and
8470 -- done as part of evaluating expressions, but the N_Range node is an
8471 -- exception, since in GNAT we consider this node to be a subexpression,
8472 -- even though in Ada it is not. The circuit in Sem_Eval could check for
8473 -- this, but that would put the test on the main evaluation path for
8474 -- expressions.
8479 -- Check for an ambiguous range over character literals. This will
8480 -- happen with a membership test involving only literals.
8488 -- If bounds are static, constant-fold them, so size computations are
8489 -- identical between front-end and back-end. Do not perform this
8490 -- transformation while analyzing generic units, as type information
8491 -- would be lost when reanalyzing the constant node in the instance.
8504 --------------------------
8505 -- Resolve_Real_Literal --
8506 --------------------------
8511 begin
8512 -- Special processing for fixed-point literals to make sure that the
8513 -- value is an exact multiple of small where this is required. We skip
8514 -- this for the universal real case, and also for generic types.
8520 then
8521 declare
8528 begin
8529 -- Case of literal is not an exact multiple of the Small
8533 -- For a source program literal for a decimal fixed-point type,
8534 -- this is statically illegal (RM 4.9(36)).
8539 then
8543 -- Generate a warning if literal from source
8546 and then Warn_On_Bad_Fixed_Value
8547 then
8548 Error_Msg_N
8550 N);
8553 -- Replace literal by a value that is the exact representation
8554 -- of a value of the type, i.e. a multiple of the small value,
8555 -- by truncation, since Machine_Rounds is false for all GNAT
8556 -- fixed-point types (RM 4.9(38)).
8566 -- In all cases, set the corresponding integer field
8572 -- Now replace the actual type by the expected type as usual
8578 -----------------------
8579 -- Resolve_Reference --
8580 -----------------------
8585 begin
8586 -- Replace general access with specific type
8594 -- If we are taking the reference of a volatile entity, then treat it as
8595 -- a potential modification of this entity. This is too conservative,
8596 -- but necessary because remove side effects can cause transformations
8597 -- of normal assignments into reference sequences that otherwise fail to
8598 -- notice the modification.
8605 --------------------------------
8606 -- Resolve_Selected_Component --
8607 --------------------------------
8622 -- Check whether this is the initialization of a component within an
8623 -- init proc (by assignment or call to another init proc). If true,
8624 -- there is no need for a discriminant check.
8626 --------------------
8627 -- Init_Component --
8628 --------------------
8631 begin
8632 return Inside_Init_Proc
8638 -- Start of processing for Resolve_Selected_Component
8640 begin
8643 -- Use the context type to select the prefix that has a selector
8644 -- of the correct name and type.
8652 else
8656 -- Locate selected component. For a private prefix the selector
8657 -- can denote a discriminant.
8661 -- The visible components of a class-wide type are those of
8662 -- the root type.
8672 then
8679 else
8683 Error_Msg_N
8688 else
8691 -- There may be an implicit dereference. Retrieve
8692 -- designated record type.
8696 else
8702 -- Resolution chooses the new interpretation.
8703 -- Find the component with the right name.
8708 loop
8729 else
8730 -- Resolve prefix with its type
8735 -- Generate cross-reference. We needed to wait until full overloading
8736 -- resolution was complete to do this, since otherwise we can't tell if
8737 -- we are an lvalue or not.
8741 else
8745 -- If prefix is an access type, the node will be transformed into an
8746 -- explicit dereference during expansion. The type of the node is the
8747 -- designated type of that of the prefix.
8752 else
8763 and then not Init_Component
8764 then
8772 -- If the prefix is a record conversion, this may be a renamed
8773 -- discriminant whose bounds differ from those of the original
8774 -- one, so we must ensure that a range check is performed.
8779 then
8783 -- Note: No Eval processing is required, because the prefix is of a
8784 -- record type, or protected type, and neither can possibly be static.
8786 -- If the array type is atomic, and is packed, and we are in a left side
8787 -- context, then this is worth a warning, since we have a situation
8788 -- where the access to the component may cause extra read/writes of the
8789 -- atomic array object, which could be considered unexpected.
8797 then
8798 Error_Msg_N
8800 Error_Msg_N
8807 -------------------
8808 -- Resolve_Shift --
8809 -------------------
8816 begin
8817 -- We do the resolution using the base type, because intermediate values
8818 -- in expressions always are of the base type, not a subtype of it.
8831 ---------------------------
8832 -- Resolve_Short_Circuit --
8833 ---------------------------
8840 begin
8844 -- Check for issuing warning for always False assert/check, this happens
8845 -- when assertions are turned off, in which case the pragma Assert/Check
8846 -- was transformed into:
8848 -- if False and then <condition> then ...
8850 -- and we detect this pattern
8852 if Warn_On_Assertion_Failure
8859 then
8860 declare
8863 begin
8866 then
8867 -- Don't want to warn if original condition is explicit False
8869 declare
8871 Original_Node
8872 (Expression
8874 begin
8877 then
8879 else
8880 -- Issue warning. We do not want the deletion of the
8881 -- IF/AND-THEN to take this message with it. We achieve
8882 -- this by making sure that the expanded code points to
8883 -- the Sloc of the expression, not the original pragma.
8885 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
8886 -- The source location of the expression is not usually
8887 -- the best choice here. For example, it gets located on
8888 -- the last AND keyword in a chain of boolean expressiond
8889 -- AND'ed together. It is best to put the message on the
8890 -- first character of the assertion, which is the effect
8891 -- of the First_Node call here.
8893 Error_Msg_F
8895 Expression
8900 -- Similar processing for Check pragma
8904 then
8905 -- Don't want to warn if original condition is explicit False
8907 declare
8909 Original_Node
8910 (Expression
8913 begin
8916 then
8919 -- Post warning
8921 else
8922 -- Again use Error_Msg_F rather than Error_Msg_N, see
8923 -- comment above for an explanation of why we do this.
8925 Error_Msg_F
8927 Expression
8935 -- Continue with processing of short circuit
8944 -------------------
8945 -- Resolve_Slice --
8946 -------------------
8954 begin
8957 -- Use the context type to select the prefix that yields the correct
8958 -- array type.
8960 declare
8967 begin
8975 then
8983 else
8988 else
8999 else
9009 -- If the prefix is an access to an unconstrained array, we must use
9010 -- the actual subtype of the object to perform the index checks. The
9011 -- object denoted by the prefix is implicit in the node, so we build
9012 -- an explicit representation for it in order to compute the actual
9013 -- subtype.
9018 declare
9022 begin
9033 then
9036 -- If the name is a selected component that depends on discriminants,
9037 -- build an actual subtype for it. This can happen only when the name
9038 -- itself is overloaded; otherwise the actual subtype is created when
9039 -- the selected component is analyzed.
9042 and then Full_Analysis
9044 then
9045 declare
9048 begin
9053 -- Maybe this should just be "else", instead of checking for the
9054 -- specific case of slice??? This is needed for the case where the
9055 -- prefix is an Image attribute, which gets expanded to a slice, and so
9056 -- has a constrained subtype which we want to use for the slice range
9057 -- check applied below (the range check won't get done if the
9058 -- unconstrained subtype of the 'Image is used).
9064 -- If name was overloaded, set slice type correctly now
9068 -- If the range is specified by a subtype mark, no resolution is
9069 -- necessary. Else resolve the bounds, and apply needed checks.
9074 else
9082 -- Ensure that side effects in the bounds are properly handled
9087 -- Do not apply the range check to nodes associated with the
9088 -- frontend expansion of the dispatch table. We first check
9089 -- if Ada.Tags is already loaded to avoid the addition of an
9090 -- undesired dependence on such run-time unit.
9092 if not Tagged_Type_Expansion
9093 or else not
9099 then
9107 -- Check bad use of type with predicates
9110 Bad_Predicated_Subtype_Use
9114 -- Otherwise here is where we check suspicious indexes
9125 ----------------------------
9126 -- Resolve_String_Literal --
9127 ----------------------------
9138 begin
9139 -- For a string appearing in a concatenation, defer creation of the
9140 -- string_literal_subtype until the end of the resolution of the
9141 -- concatenation, because the literal may be constant-folded away. This
9142 -- is a useful optimization for long concatenation expressions.
9144 -- If the string is an aggregate built for a single character (which
9145 -- happens in a non-static context) or a is null string to which special
9146 -- checks may apply, we build the subtype. Wide strings must also get a
9147 -- string subtype if they come from a one character aggregate. Strings
9148 -- generated by attributes might be static, but it is often hard to
9149 -- determine whether the enclosing context is static, so we generate
9150 -- subtypes for them as well, thus losing some rarer optimizations ???
9151 -- Same for strings that come from a static conversion.
9153 Need_Check :=
9162 -- If the resolving type is itself a string literal subtype, we can just
9163 -- reuse it, since there is no point in creating another.
9169 and then not Need_Check
9171 N_Attribute_Reference,
9172 N_Qualified_Expression,
9173 N_Type_Conversion)
9174 then
9177 -- Otherwise we must create a string literal subtype. Note that the
9178 -- whole idea of string literal subtypes is simply to avoid the need
9179 -- for building a full fledged array subtype for each literal.
9181 else
9187 or else Need_Check
9188 then
9195 then
9201 -- The validity of a null string has been checked in the call to
9202 -- Eval_String_Literal.
9207 -- Always accept string literal with component type Any_Character, which
9208 -- occurs in error situations and in comparisons of literals, both of
9209 -- which should accept all literals.
9214 -- If the type is bit-packed, then we always transform the string
9215 -- literal into a full fledged aggregate.
9220 -- Deal with cases of Wide_Wide_String, Wide_String, and String
9222 else
9223 -- For Standard.Wide_Wide_String, or any other type whose component
9224 -- type is Standard.Wide_Wide_Character, we know that all the
9225 -- characters in the string must be acceptable, since the parser
9226 -- accepted the characters as valid character literals.
9231 -- For the case of Standard.String, or any other type whose component
9232 -- type is Standard.Character, we must make sure that there are no
9233 -- wide characters in the string, i.e. that it is entirely composed
9234 -- of characters in range of type Character.
9236 -- If the string literal is the result of a static concatenation, the
9237 -- test has already been performed on the components, and need not be
9238 -- repeated.
9242 then
9246 -- If we are out of range, post error. This is one of the
9247 -- very few places that we place the flag in the middle of
9248 -- a token, right under the offending wide character. Not
9249 -- quite clear if this is right wrt wide character encoding
9250 -- sequences, but it's only an error message!
9252 Error_Msg
9259 -- For the case of Standard.Wide_String, or any other type whose
9260 -- component type is Standard.Wide_Character, we must make sure that
9261 -- there are no wide characters in the string, i.e. that it is
9262 -- entirely composed of characters in range of type Wide_Character.
9264 -- If the string literal is the result of a static concatenation,
9265 -- the test has already been performed on the components, and need
9266 -- not be repeated.
9270 then
9274 -- If we are out of range, post error. This is one of the
9275 -- very few places that we place the flag in the middle of
9276 -- a token, right under the offending wide character.
9278 -- This is not quite right, because characters in general
9279 -- will take more than one character position ???
9281 Error_Msg
9288 -- If the root type is not a standard character, then we will convert
9289 -- the string into an aggregate and will let the aggregate code do
9290 -- the checking. Standard Wide_Wide_Character is also OK here.
9292 else
9296 -- See if the component type of the array corresponding to the string
9297 -- has compile time known bounds. If yes we can directly check
9298 -- whether the evaluation of the string will raise constraint error.
9299 -- Otherwise we need to transform the string literal into the
9300 -- corresponding character aggregate and let the aggregate code do
9301 -- the checking.
9305 -- Check for the case of full range, where we are definitely OK
9311 -- Here the range is not the complete base type range, so check
9313 declare
9321 begin
9324 then
9330 then
9331 Apply_Compile_Time_Constraint_Error
9343 -- If we got here we meed to transform the string literal into the
9344 -- equivalent qualified positional array aggregate. This is rather
9345 -- heavy artillery for this situation, but it is hard work to avoid.
9347 declare
9352 begin
9353 -- Build the character literals, we give them source locations that
9354 -- correspond to the string positions, which is a bit tricky given
9355 -- the possible presence of wide character escape sequences.
9369 -- Should we have a call to Skip_Wide here ???
9371 -- ??? else
9372 -- Skip_Wide (P);
9380 Expression =>
9387 -----------------------------
9388 -- Resolve_Subprogram_Info --
9389 -----------------------------
9392 begin
9396 -----------------------------
9397 -- Resolve_Type_Conversion --
9398 -----------------------------
9410 -- Set to False to suppress cases where we want to suppress the test
9411 -- for redundancy to avoid possible false positives on this warning.
9413 begin
9414 if not Conv_OK
9416 then
9420 -- If the Operand Etype is Universal_Fixed, then the conversion is
9421 -- never redundant. We need this check because by the time we have
9422 -- finished the rather complex transformation, the conversion looks
9423 -- redundant when it is not.
9428 -- If the operand is marked as Any_Fixed, then special processing is
9429 -- required. This is also a case where we suppress the test for a
9430 -- redundant conversion, since most certainly it is not redundant.
9435 -- Mixed-mode operation involving a literal. Context must be a fixed
9436 -- type which is applied to the literal subsequently.
9444 or else
9446 then
9447 -- Return if expression is ambiguous
9452 -- If nothing else, the available fixed type is Duration
9454 else
9458 -- Resolve the real operand with largest available precision
9462 else
9468 -- If the operand is a literal (it could be a non-static and
9469 -- illegal exponentiation) check whether the use of Duration
9470 -- is potentially inaccurate.
9475 then
9476 Error_Msg_N
9479 Rop);
9480 Error_Msg_N
9487 then
9490 else
9499 -- In SPARK, a type conversion between array types should be restricted
9500 -- to types which have matching static bounds.
9502 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9503 -- operation if not needed.
9510 then
9511 Check_SPARK_Restriction
9515 -- In formal mode, the operand of an ancestor type conversion must be an
9516 -- object (not an expression).
9524 then
9530 -- Note: we do the Eval_Type_Conversion call before applying the
9531 -- required checks for a subtype conversion. This is important, since
9532 -- both are prepared under certain circumstances to change the type
9533 -- conversion to a constraint error node, but in the case of
9534 -- Eval_Type_Conversion this may reflect an illegality in the static
9535 -- case, and we would miss the illegality (getting only a warning
9536 -- message), if we applied the type conversion checks first.
9540 -- Even when evaluation is not possible, we may be able to simplify the
9541 -- conversion or its expression. This needs to be done before applying
9542 -- checks, since otherwise the checks may use the original expression
9543 -- and defeat the simplifications. This is specifically the case for
9544 -- elimination of the floating-point Truncation attribute in
9545 -- float-to-int conversions.
9549 -- If after evaluation we still have a type conversion, then we may need
9550 -- to apply checks required for a subtype conversion.
9552 -- Skip these type conversion checks if universal fixed operands
9553 -- operands involved, since range checks are handled separately for
9554 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
9560 then
9564 -- Issue warning for conversion of simple object to its own type. We
9565 -- have to test the original nodes, since they may have been rewritten
9566 -- by various optimizations.
9570 -- Here we test for a redundant conversion if the warning mode is
9571 -- active (and was not locally reset), and we have a type conversion
9572 -- from source not appearing in a generic instance.
9574 if Test_Redundant
9577 and then not In_Instance
9578 then
9582 -- If the node is part of a larger expression, the Target_Type
9583 -- may not be the original type of the node if the context is a
9584 -- condition. Recover original type to see if conversion is needed.
9588 then
9592 -- If we have an entity name, then give the warning if the entity
9593 -- is the right type, or if it is a loop parameter covered by the
9594 -- original type (that's needed because loop parameters have an
9595 -- odd subtype coming from the bounds).
9598 and then
9600 or else
9604 -- If not an entity, then type of expression must match
9607 then
9608 -- One more check, do not give warning if the analyzed conversion
9609 -- has an expression with non-static bounds, and the bounds of the
9610 -- target are static. This avoids junk warnings in cases where the
9611 -- conversion is necessary to establish staticness, for example in
9612 -- a case statement.
9616 then
9619 -- Finally, if this type conversion occurs in a context requiring
9620 -- a prefix, and the expression is a qualified expression then the
9621 -- type conversion is not redundant, since a qualified expression
9622 -- is not a prefix, whereas a type conversion is. For example, "X
9623 -- := T'(Funx(...)).Y;" is illegal because a selected component
9624 -- requires a prefix, but a type conversion makes it legal: "X :=
9625 -- T(T'(Funx(...))).Y;"
9627 -- In Ada 2012, a qualified expression is a name, so this idiom is
9628 -- no longer needed, but we still suppress the warning because it
9629 -- seems unfriendly for warnings to pop up when you switch to the
9630 -- newer language version.
9634 N_Indexed_Component,
9635 N_Selected_Component,
9636 N_Slice,
9637 N_Explicit_Dereference)
9638 then
9641 -- Never warn on conversion to Long_Long_Integer'Base since
9642 -- that is most likely an artifact of the extended overflow
9643 -- checking and comes from complex expanded code.
9648 -- Here we give the redundant conversion warning. If it is an
9649 -- entity, give the name of the entity in the message. If not,
9650 -- just mention the expression.
9652 else
9655 Error_Msg_NE -- CODEFIX
9658 else
9659 Error_Msg_NE
9667 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
9668 -- No need to perform any interface conversion if the type of the
9669 -- expression coincides with the target type.
9672 and then Full_Expander_Active
9674 then
9675 declare
9679 begin
9691 -- Conversion from interface type
9695 -- Ada 2005 (AI-217): Handle entities from limited views
9699 Error_Msg_NE -- CODEFIX
9702 Error_Msg_N
9704 N);
9707 and then not
9710 then
9712 Error_Msg_NE -- CODEFIX
9715 Error_Msg_N
9717 N);
9719 else
9723 -- Conversion to interface type
9727 -- Handle subtypes
9733 if not Interface_Present_In_Ancestor
9736 then
9739 -- The static analysis is not enough to know if the
9740 -- interface is implemented or not. Hence we must pass
9741 -- the work to the expander to generate code to evaluate
9742 -- the conversion at run time.
9746 else
9749 Error_Msg_N
9754 else
9761 -- Ada 2012: if target type has predicates, the result requires a
9762 -- predicate check. If the context is a call to another predicate
9763 -- check we must prevent infinite recursion.
9769 then
9772 else
9778 ----------------------
9779 -- Resolve_Unary_Op --
9780 ----------------------
9789 begin
9792 Check_SPARK_Restriction
9796 -- Deal with intrinsic unary operators
9802 then
9807 -- Deal with universal cases
9810 or else
9812 then
9819 -- Generate warning for expressions like abs (x mod 2)
9821 if Warn_On_Redundant_Constructs
9823 then
9827 Error_Msg_N -- CODEFIX
9832 -- Deal with reference generation
9839 -- Set overflow checking bit. Much cleverer code needed here eventually
9840 -- and perhaps the Resolve routines should be separated for the various
9841 -- arithmetic operations, since they will need different processing ???
9849 -- Generate warning for expressions like -5 mod 3 for integers. No need
9850 -- to worry in the floating-point case, since parens do not affect the
9851 -- result so there is no point in giving in a warning.
9853 declare
9862 begin
9863 if Warn_On_Questionable_Missing_Parens
9867 then
9870 -- We are looking for cases where the right operand is not
9871 -- parenthesized, and is a binary operator, multiply, divide, or
9872 -- mod. These are the cases where the grouping can affect results.
9876 then
9877 -- For mod, we always give the warning, since the value is
9878 -- affected by the parenthesization (e.g. (-5) mod 315 /=
9879 -- -(5 mod 315)). But for the other cases, the only concern is
9880 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
9881 -- overflows, but (-2) * 64 does not). So we try to give the
9882 -- message only when overflow is possible.
9886 then
9891 else
9897 else
9901 -- Note that the test below is deliberately excluding the
9902 -- largest negative number, since that is a potentially
9903 -- troublesome case (e.g. -2 * x, where the result is the
9904 -- largest negative integer has an overflow with 2 * x).
9911 -- For the multiplication case, the only case we have to worry
9912 -- about is when (-a)*b is exactly the largest negative number
9913 -- so that -(a*b) can cause overflow. This can only happen if
9914 -- a is a power of 2, and more generally if any operand is a
9915 -- constant that is not a power of 2, then the parentheses
9916 -- cannot affect whether overflow occurs. We only bother to
9917 -- test the left most operand
9919 -- Loop looking at left operands for one that has known value
9926 -- Operand value of 0 or 1 skips warning
9931 -- Otherwise check power of 2, if power of 2, warn, if
9932 -- anything else, skip warning.
9934 else
9938 else
9947 -- Keep looking at left operands
9952 -- For rem or "/" we can only have a problematic situation
9953 -- if the divisor has a value of minus one or one. Otherwise
9954 -- overflow is impossible (divisor > 1) or we have a case of
9955 -- division by zero in any case.
9960 then
9964 -- If we fall through warning should be issued
9966 Error_Msg_N
9973 ----------------------------------
9974 -- Resolve_Unchecked_Expression --
9975 ----------------------------------
9977 procedure Resolve_Unchecked_Expression
9980 is
9981 begin
9986 ---------------------------------------
9987 -- Resolve_Unchecked_Type_Conversion --
9988 ---------------------------------------
9990 procedure Resolve_Unchecked_Type_Conversion
9993 is
9999 begin
10000 -- Resolve operand using its own type
10007 ------------------------------
10008 -- Rewrite_Operator_As_Call --
10009 ------------------------------
10016 begin
10023 New_N :=
10034 ------------------------------
10035 -- Rewrite_Renamed_Operator --
10036 ------------------------------
10038 procedure Rewrite_Renamed_Operator
10042 is
10047 begin
10048 -- Rewrite the operator node using the real operator, not its renaming.
10049 -- Exclude user-defined intrinsic operations of the same name, which are
10050 -- treated separately and rewritten as calls.
10059 -- Indicate that both the original entity and its renaming are
10060 -- referenced at this point.
10071 -- If the context type is private, add the appropriate conversions so
10072 -- that the operator is applied to the full view. This is done in the
10073 -- routines that resolve intrinsic operators.
10077 then
10079 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
10080 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
10093 -- Operator renames a user-defined operator of the same name. Use the
10094 -- original operator in the node, which is the one Gigi knows about.
10101 -----------------------
10102 -- Set_Slice_Subtype --
10103 -----------------------
10105 -- Build an implicit subtype declaration to represent the type delivered by
10106 -- the slice. This is an abbreviated version of an array subtype. We define
10107 -- an index subtype for the slice, using either the subtype name or the
10108 -- discrete range of the slice. To be consistent with index usage elsewhere
10109 -- we create a list header to hold the single index. This list is not
10110 -- otherwise attached to the syntax tree.
10121 begin
10125 else
10126 -- We force the evaluation of a range. This is definitely needed in
10127 -- the renamed case, and seems safer to do unconditionally. Note in
10128 -- any case that since we will create and insert an Itype referring
10129 -- to this range, we must make sure any side effect removal actions
10130 -- are inserted before the Itype definition.
10141 -- Take a new copy of Drange (where bounds have been rewritten to
10142 -- reference side-effect-free names). Using a separate tree ensures
10143 -- that further expansion (e.g. while rewriting a slice assignment
10144 -- into a FOR loop) does not attempt to remove side effects on the
10145 -- bounds again (which would cause the bounds in the index subtype
10146 -- definition to refer to temporaries before they are defined) (the
10147 -- reason is that some names are considered side effect free here
10148 -- for the subtype, but not in the context of a loop iteration
10149 -- scheme).
10170 -- The Etype of the existing Slice node is reset to this slice subtype.
10171 -- Its bounds are obtained from its first index.
10175 -- For packed slice subtypes, freeze immediately (except in the case of
10176 -- being in a "spec expression" where we never freeze when we first see
10177 -- the expression).
10182 -- For all other cases insert an itype reference in the slice's actions
10183 -- so that the itype is frozen at the proper place in the tree (i.e. at
10184 -- the point where actions for the slice are analyzed). Note that this
10185 -- is different from freezing the itype immediately, which might be
10186 -- premature (e.g. if the slice is within a transient scope). This needs
10187 -- to be done only if expansion is enabled.
10194 --------------------------------
10195 -- Set_String_Literal_Subtype --
10196 --------------------------------
10204 begin
10216 -- The low bound is set from the low bound of the corresponding index
10217 -- type. Note that we do not store the high bound in the string literal
10218 -- subtype, but it can be deduced if necessary from the length and the
10219 -- low bound.
10224 -- If the lower bound is not static we create a range for the string
10225 -- literal, using the index type and the known length of the literal.
10226 -- The index type is not necessarily Positive, so the upper bound is
10227 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
10229 else
10230 declare
10236 Prefix =>
10240 Left_Opnd =>
10243 Prefix =>
10245 Expressions =>
10247 Right_Opnd =>
10256 begin
10258 Set_String_Literal_Low_Bound
10261 else
10262 -- If the index type is an enumeration type, build bounds
10263 -- expression with attributes.
10265 Set_String_Literal_Low_Bound
10269 Prefix =>
10276 -- Build bona fide subtype for the string, and wrap it in an
10277 -- unchecked conversion, because the backend expects the
10278 -- String_Literal_Subtype to have a static lower bound.
10280 Index_Subtype :=
10287 -- In the context, the Index_Type may already have a constraint,
10288 -- so use common base type on string subtype. The base type may
10289 -- be used when generating attributes of the string, for example
10290 -- in the context of a slice assignment.
10315 ------------------------------
10316 -- Simplify_Type_Conversion --
10317 ------------------------------
10320 begin
10322 declare
10327 begin
10329 and then
10336 -- Special processing required if the conversion is the expression
10337 -- of a Truncation attribute reference. In this case we replace:
10339 -- ityp (ftyp'Truncation (x))
10341 -- by
10343 -- ityp (x)
10345 -- with the Float_Truncate flag set, which is more efficient.
10347 then
10356 -----------------------------
10357 -- Unique_Fixed_Point_Type --
10358 -----------------------------
10367 -- Give error messages for true ambiguity. Messages are posted on node
10368 -- N, and entities T1, T2 are the possible interpretations.
10370 -----------------------
10371 -- Fixed_Point_Error --
10372 -----------------------
10375 begin
10381 -- Start of processing for Unique_Fixed_Point_Type
10383 begin
10384 -- The operations on Duration are visible, so Duration is always a
10385 -- possible interpretation.
10389 -- Look for fixed-point types in enclosing scopes
10398 then
10400 Fixed_Point_Error;
10402 else
10413 -- Look for visible fixed type declarations in the context
10424 then
10426 Fixed_Point_Error;
10428 else
10442 else
10449 ----------------------
10450 -- Valid_Conversion --
10451 ----------------------
10453 function Valid_Conversion
10458 is
10462 function Conversion_Check
10465 -- Little routine to post Msg if Valid is False, returns Valid value
10467 -- The following are badly named, this kind of overloading is actively
10468 -- confusing in reading code, please rename to something like
10469 -- Error_Msg_N_If_Reporting ???
10472 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
10474 procedure Error_Msg_NE
10478 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
10480 function Valid_Tagged_Conversion
10483 -- Specifically test for validity of tagged conversions
10486 -- Check index and component conformance, and accessibility levels if
10487 -- the component types are anonymous access types (Ada 2005).
10489 ----------------------
10490 -- Conversion_Check --
10491 ----------------------
10493 function Conversion_Check
10496 is
10497 begin
10498 if not Valid
10500 -- A generic unit has already been analyzed and we have verified
10501 -- that a particular conversion is OK in that context. Since the
10502 -- instance is reanalyzed without relying on the relationships
10503 -- established during the analysis of the generic, it is possible
10504 -- to end up with inconsistent views of private types. Do not emit
10505 -- the error message in such cases. The rest of the machinery in
10506 -- Valid_Conversion still ensures the proper compatibility of
10507 -- target and operand types.
10509 and then not In_Instance
10510 then
10517 -----------------
10518 -- Error_Msg_N --
10519 -----------------
10522 begin
10528 ------------------
10529 -- Error_Msg_NE --
10530 ------------------
10532 procedure Error_Msg_NE
10536 is
10537 begin
10543 ----------------------------
10544 -- Valid_Array_Conversion --
10545 ----------------------------
10548 is
10563 begin
10564 -- Error if wrong number of dimensions
10566 if
10568 then
10569 Error_Msg_N
10573 -- Number of dimensions matches
10575 else
10576 -- Loop through indexes of the two arrays
10584 -- Error if index types are incompatible
10590 then
10591 Error_Msg_N
10593 Operand);
10601 -- If component types have same base type, all set
10606 -- Here if base types of components are not the same. The only
10607 -- time this is allowed is if we have anonymous access types.
10609 -- The conversion of arrays of anonymous access types can lead
10610 -- to dangling pointers. AI-392 formalizes the accessibility
10611 -- checks that must be applied to such conversions to prevent
10612 -- out-of-scope references.
10614 elsif Ekind_In
10616 E_Anonymous_Access_Subprogram_Type)
10618 and then
10620 then
10623 then
10625 Error_Msg_N
10628 Error_Msg_N
10630 Operand);
10637 -- Conversion not allowed because of accessibility levels
10639 else
10640 Error_Msg_N
10646 else
10650 -- All other cases where component base types do not match
10652 else
10653 Error_Msg_N
10655 Operand);
10659 -- Check that component subtypes statically match. For numeric
10660 -- types this means that both must be either constrained or
10661 -- unconstrained. For enumeration types the bounds must match.
10662 -- All of this is checked in Subtypes_Statically_Match.
10664 if not Subtypes_Statically_Match
10666 then
10667 Error_Msg_N
10676 -----------------------------
10677 -- Valid_Tagged_Conversion --
10678 -----------------------------
10680 function Valid_Tagged_Conversion
10683 is
10684 begin
10685 -- Upward conversions are allowed (RM 4.6(22))
10689 then
10692 -- Downward conversion are allowed if the operand is class-wide
10693 -- (RM 4.6(23)).
10697 then
10702 then
10703 return
10707 -- Ada 2005 (AI-251): The conversion to/from interface types is
10708 -- always valid
10713 -- If the operand is a class-wide type obtained through a limited_
10714 -- with clause, and the context includes the non-limited view, use
10715 -- it to determine whether the conversion is legal.
10721 then
10726 then
10729 else
10730 Error_Msg_NE
10737 -- Start of processing for Valid_Conversion
10739 begin
10743 declare
10751 begin
10752 -- Remove procedure calls, which syntactically cannot appear in
10753 -- this context, but which cannot be removed by type checking,
10754 -- because the context does not impose a type.
10756 -- When compiling for VMS, spurious ambiguities can be produced
10757 -- when arithmetic operations have a literal operand and return
10758 -- System.Address or a descendant of it. These ambiguities are
10759 -- otherwise resolved by the context, but for conversions there
10760 -- is no context type and the removal of the spurious operations
10761 -- must be done explicitly here.
10763 -- The node may be labelled overloaded, but still contain only one
10764 -- interpretation because others were discarded earlier. If this
10765 -- is the case, retain the single interpretation if legal.
10773 then
10774 -- More than one candidate interpretation is available
10784 then
10811 -- If the interpretation involves a standard operator, use
10812 -- the location of the type, which may be user-defined.
10816 else
10820 Error_Msg_N -- CODEFIX
10825 else
10829 Error_Msg_N -- CODEFIX
10841 -- Numeric types
10845 -- A universal fixed expression can be converted to any numeric type
10850 -- Also no need to check when in an instance or inlined body, because
10851 -- the legality has been established when the template was analyzed.
10852 -- Furthermore, numeric conversions may occur where only a private
10853 -- view of the operand type is visible at the instantiation point.
10854 -- This results in a spurious error if we check that the operand type
10855 -- is a numeric type.
10857 -- Note: in a previous version of this unit, the following tests were
10858 -- applied only for generated code (Comes_From_Source set to False),
10859 -- but in fact the test is required for source code as well, since
10860 -- this situation can arise in source code.
10865 -- Otherwise we need the conversion check
10867 else
10868 return Conversion_Check
10873 -- Array types
10879 then
10882 else
10886 -- Ada 2005 (AI-251): Anonymous access types where target references an
10887 -- interface type.
10890 E_Anonymous_Access_Type)
10892 then
10893 -- Check the static accessibility rule of 4.6(17). Note that the
10894 -- check is not enforced when within an instance body, since the
10895 -- RM requires such cases to be caught at run time.
10897 -- If the operand is a rewriting of an allocator no check is needed
10898 -- because there are no accessibility issues.
10906 then
10907 -- In an instance, this is a run-time check, but one we know
10908 -- will fail, so generate an appropriate warning. The raise
10909 -- will be generated by Expand_N_Type_Conversion.
10912 Error_Msg_N
10914 Operand);
10915 Error_Msg_N
10918 else
10919 Error_Msg_N
10921 Operand);
10925 -- Special accessibility checks are needed in the case of access
10926 -- discriminants declared for a limited type.
10930 then
10931 -- When the operand is a selected access discriminant the check
10932 -- needs to be made against the level of the object denoted by
10933 -- the prefix of the selected name (Object_Access_Level handles
10934 -- checking the prefix of the operand for this case).
10939 then
10940 -- In an instance, this is a run-time check, but one we know
10941 -- will fail, so generate an appropriate warning. The raise
10942 -- will be generated by Expand_N_Type_Conversion.
10945 Error_Msg_N
10948 Error_Msg_N
10950 else
10951 Error_Msg_N
10958 -- The case of a reference to an access discriminant from
10959 -- within a limited type declaration (which will appear as
10960 -- a discriminal) is always illegal because the level of the
10961 -- discriminant is considered to be deeper than any (nameable)
10962 -- access type.
10966 and then
10969 then
10970 Error_Msg_N
10972 Operand);
10980 -- General and anonymous access types
10983 E_Anonymous_Access_Type)
10984 and then
10985 Conversion_Check
10987 and then not
10989 E_Access_Protected_Subprogram_Type),
10991 then
10994 then
10995 Error_Msg_N
11000 -- Check the static accessibility rule of 4.6(17). Note that the
11001 -- check is not enforced when within an instance body, since the RM
11002 -- requires such cases to be caught at run time.
11007 N_Object_Declaration
11008 then
11009 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
11010 -- conversions from an anonymous access type to a named general
11011 -- access type. Such conversions are not allowed in the case of
11012 -- access parameters and stand-alone objects of an anonymous
11013 -- access type. The implicit conversion case is recognized by
11014 -- testing that Comes_From_Source is False and that it's been
11015 -- rewritten. The Comes_From_Source test isn't sufficient because
11016 -- nodes in inlined calls to predefined library routines can have
11017 -- Comes_From_Source set to False. (Is there a better way to test
11018 -- for implicit conversions???)
11025 then
11028 -- Implicit conversions aren't allowed for objects of an
11029 -- anonymous access type, since such objects have nonstatic
11030 -- levels in Ada 2012.
11033 N_Object_Declaration
11034 then
11035 Error_Msg_N
11040 -- Implicit conversions aren't allowed for anonymous access
11041 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
11042 -- is done to exclude anonymous access results.
11046 N_Function_Specification,
11047 N_Procedure_Specification)
11048 then
11049 Error_Msg_N
11054 -- This is a case where there's an enclosing object whose
11055 -- to which the "statically deeper than" relationship does
11056 -- not apply (such as an access discriminant selected from
11057 -- a dereference of an access parameter).
11061 then
11062 Error_Msg_N
11067 -- In other cases, the level of the operand's type must be
11068 -- statically less deep than that of the target type, else
11069 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
11073 then
11074 Error_Msg_N
11083 then
11084 -- In an instance, this is a run-time check, but one we know
11085 -- will fail, so generate an appropriate warning. The raise
11086 -- will be generated by Expand_N_Type_Conversion.
11089 Error_Msg_N
11091 Operand);
11092 Error_Msg_N
11095 else
11096 -- Avoid generation of spurious error message
11099 Error_Msg_N
11101 Operand);
11107 -- Special accessibility checks are needed in the case of access
11108 -- discriminants declared for a limited type.
11112 then
11113 -- When the operand is a selected access discriminant the check
11114 -- needs to be made against the level of the object denoted by
11115 -- the prefix of the selected name (Object_Access_Level handles
11116 -- checking the prefix of the operand for this case).
11121 then
11122 -- In an instance, this is a run-time check, but one we know
11123 -- will fail, so generate an appropriate warning. The raise
11124 -- will be generated by Expand_N_Type_Conversion.
11127 Error_Msg_N
11130 Error_Msg_N
11132 Operand);
11134 else
11135 Error_Msg_N
11142 -- The case of a reference to an access discriminant from
11143 -- within a limited type declaration (which will appear as
11144 -- a discriminal) is always illegal because the level of the
11145 -- discriminant is considered to be deeper than any (nameable)
11146 -- access type.
11149 and then
11152 then
11153 Error_Msg_N
11155 Operand);
11161 -- In the presence of limited_with clauses we have to use non-limited
11162 -- views, if available.
11166 -- Helper function to handle limited views
11168 --------------------------
11169 -- Full_Designated_Type --
11170 --------------------------
11175 begin
11176 -- Handle the limited view of a type
11181 then
11183 else
11188 -- Local Declarations
11196 -- Start of processing for Check_Limited
11198 begin
11202 else
11204 Error_Msg_NE
11209 -- Ada 2005 AI-384: legality rule is symmetric in both
11210 -- designated types. The conversion is legal (with possible
11211 -- constraint check) if either designated type is
11212 -- unconstrained.
11215 or else
11217 and then
11220 then
11221 -- Special case, if Value_Size has been used to make the
11222 -- sizes different, the conversion is not allowed even
11223 -- though the subtypes statically match.
11228 then
11229 Error_Msg_NE
11232 Error_Msg_NE
11237 -- Normal case where conversion is allowed
11239 else
11243 else
11244 Error_Msg_NE
11252 -- Access to subprogram types. If the operand is an access parameter,
11253 -- the type has a deeper accessibility that any master, and cannot be
11254 -- assigned. We must make an exception if the conversion is part of an
11255 -- assignment and the target is the return object of an extended return
11256 -- statement, because in that case the accessibility check takes place
11257 -- after the return.
11261 then
11265 and then
11269 then
11270 Error_Msg_N
11272 Operand);
11273 Error_Msg_N
11276 Operand);
11278 Error_Msg_NE
11283 -- Check that the designated types are subtype conformant
11289 -- Check the static accessibility rule of 4.6(20)
11293 then
11294 Error_Msg_N
11296 Operand);
11298 -- Check that if the operand type is declared in a generic body,
11299 -- then the target type must be declared within that same body
11300 -- (enforces last sentence of 4.6(20)).
11303 declare
11309 begin
11316 Error_Msg_N
11325 -- Remote subprogram access types
11329 then
11330 -- It is valid to convert from one RAS type to another provided
11331 -- that their specification statically match.
11333 Check_Subtype_Conformant
11336 Old_Id =>
11338 Err_Loc =>
11339 N);
11342 -- If it was legal in the generic, it's legal in the instance
11347 -- If both are tagged types, check legality of view conversions
11350 and then
11352 then
11355 -- Types derived from the same root type are convertible
11360 -- In an instance or an inlined body, there may be inconsistent views of
11361 -- the same type, or of types derived from a common root.
11364 and then
11367 then
11370 -- Special check for common access type error case
11374 then
11376 Error_Msg_NE -- CODEFIX
11380 else