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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) 1992-2006, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
76 -----------------------
77 -- Local Subprograms --
78 -----------------------
80 -- Second pass (top-down) type checking and overload resolution procedures
81 -- Typ is the type required by context. These procedures propagate the
82 -- type information recursively to the descendants of N. If the node
83 -- is not overloaded, its Etype is established in the first pass. If
84 -- overloaded, the Resolve routines set the correct type. For arith.
85 -- operators, the Etype is the base type of the context.
87 -- Note that Resolve_Attribute is separated off in Sem_Attr
90 -- Give list of candidate interpretations when a character literal cannot
91 -- be resolved.
94 -- Enforce the restrictions on the use of discriminants when constraining
95 -- a component of a discriminated type (record or concurrent type).
98 -- Given a node for an operator associated with type T, check that
99 -- the operator is visible. Operators all of whose operands are
100 -- universal must be checked for visibility during resolution
101 -- because their type is not determinable based on their operands.
103 procedure Check_Fully_Declared_Prefix
106 -- Check that the type of the prefix of a dereference is not incomplete
109 -- Given a call node, N, which is known to occur immediately within the
110 -- subprogram being called, determines whether it is a detectable case of
111 -- an infinite recursion, and if so, outputs appropriate messages. Returns
112 -- True if an infinite recursion is detected, and False otherwise.
115 -- If the type of the object being initialized uses the secondary stack
116 -- directly or indirectly, create a transient scope for the call to the
117 -- init proc. This is because we do not create transient scopes for the
118 -- initialization of individual components within the init proc itself.
119 -- Could be optimized away perhaps?
122 -- Utility to check whether the name in the call is a predefined
123 -- operator, in which case the call is made into an operator node.
124 -- An instance of an intrinsic conversion operation may be given
125 -- an operator name, but is not treated like an operator.
128 -- If a default expression in entry call N depends on the discriminants
129 -- of the task, it must be replaced with a reference to the discriminant
130 -- of the task being called.
165 function Operator_Kind
168 -- Utility to map the name of an operator into the corresponding Node. Used
169 -- by other node rewriting procedures.
172 -- Resolve actuals of call, and add default expressions for missing ones.
173 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
174 -- called subprogram.
177 -- Called from Resolve_Call, when the prefix denotes an entry or element
178 -- of entry family. Actuals are resolved as for subprograms, and the node
179 -- is rebuilt as an entry call. Also called for protected operations. Typ
180 -- is the context type, which is used when the operation is a protected
181 -- function with no arguments, and the return value is indexed.
184 -- A call to a user-defined intrinsic operator is rewritten as a call
185 -- to the corresponding predefined operator, with suitable conversions.
188 -- Ditto, for unary operators (only arithmetic ones)
191 -- If an operator node resolves to a call to a user-defined operator,
192 -- rewrite the node as a function call.
194 procedure Make_Call_Into_Operator
198 -- Inverse transformation: if an operator is given in functional notation,
199 -- then after resolving the node, transform into an operator node, so
200 -- that operands are resolved properly. Recall that predefined operators
201 -- do not have a full signature and special resolution rules apply.
203 procedure Rewrite_Renamed_Operator
207 -- An operator can rename another, e.g. in an instantiation. In that
208 -- case, the proper operator node must be constructed and resolved.
211 -- The String_Literal_Subtype is built for all strings that are not
212 -- operands of a static concatenation operation. If the argument is
213 -- not a N_String_Literal node, then the call has no effect.
216 -- Build subtype of array type, with the range specified by the slice
219 -- A universal_fixed expression in an universal context is unambiguous
220 -- if there is only one applicable fixed point type. Determining whether
221 -- there is only one requires a search over all visible entities, and
222 -- happens only in very pathological cases (see 6115-006).
224 function Valid_Conversion
228 -- Verify legality rules given in 4.6 (8-23). Target is the target
229 -- type of the conversion, which may be an implicit conversion of
230 -- an actual parameter to an anonymous access type (in which case
231 -- N denotes the actual parameter and N = Operand).
233 -------------------------
234 -- Ambiguous_Character --
235 -------------------------
240 begin
243 Error_Msg_N
254 -------------------------
255 -- Analyze_And_Resolve --
256 -------------------------
259 begin
265 begin
270 -- Version withs check(s) suppressed
272 procedure Analyze_And_Resolve
276 is
279 begin
281 declare
283 begin
289 else
290 declare
293 begin
301 and then Scope_Is_Transient
302 then
303 -- This can only happen if a transient scope was created
304 -- for an inner expression, which will be removed upon
305 -- completion of the analysis of an enclosing construct.
306 -- The transient scope must have the suppress status of
307 -- the enclosing environment, not of this Analyze call.
310 Scope_Suppress;
314 procedure Analyze_And_Resolve
317 is
320 begin
322 declare
324 begin
330 else
331 declare
334 begin
342 and then Scope_Is_Transient
343 then
345 Scope_Suppress;
349 ----------------------------
350 -- Check_Discriminant_Use --
351 ----------------------------
359 begin
360 -- Any use in a default expression is legal
367 -- Discriminant cannot be used to constrain a scalar type
374 then
379 -- The following check catches the unusual case where
380 -- a discriminant appears within an index constraint
381 -- that is part of a larger expression within a constraint
382 -- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
383 -- For now we only check case of record components, and
384 -- note that a similar check should also apply in the
385 -- case of discriminant constraints below. ???
387 -- Note that the check for N_Subtype_Declaration below is to
388 -- detect the valid use of discriminants in the constraints of a
389 -- subtype declaration when this subtype declaration appears
390 -- inside the scope of a record type (which is syntactically
391 -- illegal, but which may be created as part of derived type
392 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
393 -- for more info.
397 and then not
399 and then
401 or else
404 then
405 Error_Msg_N
410 -- Detect a common beginner error:
412 -- type R (D : Positive := 100) is record
413 -- Name : String (1 .. D);
414 -- end record;
416 -- The default value causes an object of type R to be
417 -- allocated with room for Positive'Last characters.
419 declare
426 -- Return True if type T has a large enough range that
427 -- any array whose index type covered the whole range of
428 -- the type would likely raise Storage_Error.
430 ------------------------
431 -- Large_Storage_Type --
432 ------------------------
435 begin
436 return
437 T = Standard_Integer
438 or else
439 T = Standard_Positive
440 or else
444 begin
445 -- Check that the Disc has a large range
451 -- If the enclosing type is limited, we allocate only the
452 -- default value, not the maximum, and there is no need for
453 -- a warning.
459 -- Check that it is the high bound
463 then
467 -- Check the array allows a large range at this bound.
468 -- First find the array
482 -- Next, find the dimension
490 loop
499 -- Now, check the dimension has a large range
505 -- Warn about the danger
507 Error_Msg_N
517 -- Legal case is in index or discriminant constraint
521 then
523 Error_Msg_N
528 then
529 Error_Msg_N
535 -- Otherwise, context is an expression. It should not be within
536 -- (i.e. a subexpression of) a constraint for a component.
538 else
544 loop
550 -- If the discriminant is used in an expression that is a bound
551 -- of a scalar type, an Itype is created and the bounds are attached
552 -- to its range, not to the original subtype indication. Such use
553 -- is of course a double fault.
556 and then
558 or else
562 -- The constraint itself may be given by a subtype indication,
563 -- rather than by a more common discrete range.
566 and then
570 then
571 Error_Msg_N
577 --------------------------------
578 -- Check_For_Visible_Operator --
579 --------------------------------
582 begin
584 Error_Msg_NE
590 ----------------------------------
591 -- Check_Fully_Declared_Prefix --
592 ----------------------------------
594 procedure Check_Fully_Declared_Prefix
597 is
598 begin
599 -- Check that the designated type of the prefix of a dereference is
600 -- not an incomplete type. This cannot be done unconditionally, because
601 -- dereferences of private types are legal in default expressions. This
602 -- case is taken care of in Check_Fully_Declared, called below. There
603 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
605 -- This consideration also applies to similar checks for allocators,
606 -- qualified expressions, and type conversions.
608 -- An additional exception concerns other per-object expressions that
609 -- are not directly related to component declarations, in particular
610 -- representation pragmas for tasks. These will be per-object
611 -- expressions if they depend on discriminants or some global entity.
612 -- If the task has access discriminants, the designated type may be
613 -- incomplete at the point the expression is resolved. This resolution
614 -- takes place within the body of the initialization procedure, where
615 -- the discriminant is replaced by its discriminal.
619 then
622 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
623 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
624 -- Analyze_Object_Renaming, and Freeze_Entity.
629 E_Incomplete_Type
631 then
633 else
638 ------------------------------
639 -- Check_Infinite_Recursion --
640 ------------------------------
647 -- Check whether list of actuals is identical to list of formals
648 -- of called function (which is also the enclosing scope).
650 ------------------------
651 -- Same_Argument_List --
652 ------------------------
659 begin
662 else
671 then
682 -- Start of processing for Check_Infinite_Recursion
684 begin
685 -- Loop moving up tree, quitting if something tells us we are
686 -- definitely not in an infinite recursion situation.
689 loop
697 then
702 then
703 -- If the call is the expression of a return statement and
704 -- the actuals are identical to the formals, it's worth a
705 -- warning. However, we skip this if there is an immediately
706 -- preceding raise statement, since the call is never executed.
708 -- Furthermore, this corresponds to a common idiom:
710 -- function F (L : Thing) return Boolean is
711 -- begin
712 -- raise Program_Error;
713 -- return F (L);
714 -- end F;
716 -- for generating a stub function
719 and then Same_Argument_List
720 then
723 -- OK, return statement is in a statement list, look for raise
725 declare
728 begin
729 -- Skip past N_Freeze_Entity nodes generated by expansion
734 loop
738 -- If no raise statement, give warning
741 and then
749 else
760 -------------------------------
761 -- Check_Initialization_Call --
762 -------------------------------
768 -- Check whether the creation of an object of the type will involve
769 -- use of the secondary stack. If T is a record type, this is true
770 -- if the expression for some component uses the secondary stack, eg.
771 -- through a call to a function that returns an unconstrained value.
772 -- False if T is controlled, because cleanups occur elsewhere.
774 -------------
775 -- Uses_SS --
776 -------------
782 begin
794 then
797 -- The expression for a dynamic component may be
798 -- rewritten as a dereference. Retrieve original
799 -- call.
803 then
816 else
821 -- Start of processing for Check_Initialization_Call
823 begin
824 -- Nothing to do if functions do not use the secondary stack for
825 -- returns (i.e. they use a depressed stack pointer instead).
830 -- Otherwise establish a transient scope if the type needs it
837 ------------------------------
838 -- Check_Parameterless_Call --
839 ------------------------------
845 -- If the prefix is of an access_to_subprogram type, the node must be
846 -- rewritten as a call. Ditto if the prefix is overloaded and all its
847 -- interpretations are access to subprograms.
849 ---------------------------
850 -- Prefix_Is_Access_Subp --
851 ---------------------------
857 begin
859 return
862 else
867 then
878 -- Start of processing for Check_Parameterless_Call
880 begin
881 -- Defend against junk stuff if errors already detected
888 then
895 -- If the context expects a value, and the name is a procedure,
896 -- this is most likely a missing 'Access. Do not try to resolve
897 -- the parameterless call, error will be caught when the outer
898 -- call is analyzed.
903 and then
907 then
911 -- Rewrite as call if overloadable entity that is (or could be, in
912 -- the overloaded case) a function call. If we know for sure that
913 -- the entity is an enumeration literal, we do not rewrite it.
920 -- Rewrite as call if it is an explicit deference of an expression of
921 -- a subprogram access type, and the suprogram type is not that of a
922 -- procedure or entry.
924 or else
927 -- Rewrite as call if it is a selected component which is a function,
928 -- this is the case of a call to a protected function (which may be
929 -- overloaded with other protected operations).
931 or else
934 or else
936 or else
940 -- If one of the above three conditions is met, rewrite as call.
941 -- Apply the rewriting only once.
943 then
946 then
949 -- If overloaded, overload set belongs to new copy
953 -- Change node to parameterless function call (note that the
954 -- Parameter_Associations associations field is left set to Empty,
955 -- its normal default value since there are no parameters)
968 ----------------------
969 -- Is_Predefined_Op --
970 ----------------------
973 begin
981 -----------------------------
982 -- Make_Call_Into_Operator --
983 -----------------------------
985 procedure Make_Call_Into_Operator
989 is
1004 -- Determine whether E is an access type declared by an access decla-
1005 -- ration, and not an (anonymous) allocator type.
1008 -- If the operand is not universal, and the operator is given by a
1009 -- expanded name, verify that the operand has an interpretation with
1010 -- a type defined in the given scope of the operator.
1013 -- Find a type of the given class in the package Pack that contains
1014 -- the operator.
1016 -----------------------------
1017 -- Is_Definite_Access_Type --
1018 -----------------------------
1022 begin
1028 ---------------------------
1029 -- Operand_Type_In_Scope --
1030 ---------------------------
1037 begin
1041 else
1055 ---------------
1056 -- Type_In_P --
1057 ---------------
1063 -- Verify that node is not part of the type declaration for the
1064 -- candidate type, which would otherwise be invisible.
1066 -------------
1067 -- In_Decl --
1068 -------------
1074 begin
1083 else
1086 loop
1089 else
1098 -- Start of processing for Type_In_P
1100 begin
1101 -- If the context type is declared in the prefix package, this
1102 -- is the desired base type.
1106 then
1109 else
1113 and then not In_Decl
1114 then
1125 -- Start of processing for Make_Call_Into_Operator
1127 begin
1130 -- Binary operator
1140 -- Unary operator
1142 else
1148 -- If the operator is denoted by an expanded name, and the prefix is
1149 -- not Standard, but the operator is a predefined one whose scope is
1150 -- Standard, then this is an implicit_operator, inserted as an
1151 -- interpretation by the procedure of the same name. This procedure
1152 -- overestimates the presence of implicit operators, because it does
1153 -- not examine the type of the operands. Verify now that the operand
1154 -- type appears in the given scope. If right operand is universal,
1155 -- check the other operand. In the case of concatenation, either
1156 -- argument can be the component type, so check the type of the result.
1157 -- If both arguments are literals, look for a type of the right kind
1158 -- defined in the given scope. This elaborate nonsense is brought to
1159 -- you courtesy of b33302a. The type itself must be frozen, so we must
1160 -- find the type of the proper class in the given scope.
1162 -- A final wrinkle is the multiplication operator for fixed point
1163 -- types, which is defined in Standard only, and not in the scope of
1164 -- the fixed_point type itself.
1169 -- If the entity being called is defined in the given package,
1170 -- it is a renaming of a predefined operator, and known to be
1171 -- legal.
1175 then
1178 -- Visibility does not need to be checked in an instance: if the
1179 -- operator was not visible in the generic it has been diagnosed
1180 -- already, else there is an implicit copy of it in the instance.
1189 then
1194 -- Ada 2005, AI-420: Predefined equality on Universal_Access
1195 -- is available.
1200 then
1203 else
1212 and then Is_Binary
1214 then
1220 -- Verify that the scope contains a type that corresponds to
1221 -- the given literal. Optimize the case where Pack is Standard.
1243 else
1252 else
1261 then
1264 -- If the type is defined elsewhere, and the operator is not
1265 -- defined in the given scope (by a renaming declaration, e.g.)
1266 -- then this is an error as well. If an extension of System is
1267 -- present, and the type may be defined there, Pack must be
1268 -- System itself.
1275 then
1278 else
1284 then
1291 Error_Msg_NE
1302 else
1306 -- If this is a call to a function that renames a predefined equality,
1307 -- the renaming declaration provides a type that must be used to
1308 -- resolve the operands. This must be done now because resolution of
1309 -- the equality node will not resolve any remaining ambiguity, and it
1310 -- assumes that the first operand is not overloaded.
1315 then
1324 -- If this is an arithmetic operator and the result type is private,
1325 -- the operands and the result must be wrapped in conversion to
1326 -- expose the underlying numeric type and expand the proper checks,
1327 -- e.g. on division.
1331 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1332 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1341 else
1345 -- For predefined operators on literals, the operation freezes
1346 -- their type.
1354 -------------------
1355 -- Operator_Kind --
1356 -------------------
1358 function Operator_Kind
1361 is
1364 begin
1383 else
1387 -- Unary operators
1389 else
1394 else
1402 -----------------------------
1403 -- Pre_Analyze_And_Resolve --
1404 -----------------------------
1409 begin
1413 -- We suppress all checks for this analysis, since the checks will
1414 -- be applied properly, and in the right location, when the default
1415 -- expression is reanalyzed and reexpanded later on.
1419 Expander_Mode_Restore;
1423 -- Version without context type
1428 begin
1435 Expander_Mode_Restore;
1439 ----------------------------------
1440 -- Replace_Actual_Discriminants --
1441 ----------------------------------
1449 -------------------
1450 -- Process_Discr --
1451 -------------------
1456 begin
1462 then
1478 -- Start of processing for Replace_Actual_Discriminants
1480 begin
1494 else
1499 -------------
1500 -- Resolve --
1501 -------------
1516 -- Try and fix up a literal so that it matches its expected type. New
1517 -- literals are manufactured if necessary to avoid cascaded errors.
1520 -- Called when attempt at resolving current expression fails
1522 --------------------
1523 -- Patch_Up_Value --
1524 --------------------
1527 begin
1530 then
1539 then
1547 then
1552 Char_Literal_Value =>
1559 then
1570 -----------------------
1571 -- Resolution_Failed --
1572 -----------------------
1575 begin
1581 -- The caller will return without calling the expander, so we need
1582 -- to set the analyzed flag. Note that it is fine to set Analyzed
1583 -- to True even if we are in the middle of a shallow analysis,
1584 -- (see the spec of sem for more details) since this is an error
1585 -- situation anyway, and there is no point in repeating the
1586 -- analysis later (indeed it won't work to repeat it later, since
1587 -- we haven't got a clear resolution of which entity is being
1588 -- referenced.)
1594 -- Start of processing for Resolve
1596 begin
1601 -- Access attribute on remote subprogram cannot be used for
1602 -- a non-remote access-to-subprogram type.
1613 then
1614 Error_Msg_N
1618 -- If the context is a Remote_Access_To_Subprogram, access attributes
1619 -- must be resolved with the corresponding fat pointer. There is no need
1620 -- to check for the attribute name since the return type of an
1621 -- attribute is never a remote type.
1627 then
1628 declare
1636 begin
1637 -- Check that Typ is a remote access-to-subprogram type
1640 -- Prefix (N) must statically denote a remote subprogram
1641 -- declared in a package specification.
1658 or else
1660 then
1662 Error_Msg_N
1664 N);
1668 -- If we are generating code for a distributed program.
1669 -- perform semantic checks against the corresponding
1670 -- remote entities.
1675 and then Expander_Active
1677 then
1678 Check_Subtype_Conformant
1680 Old_Id => Designated_Type
1700 then
1705 -- Return if already analyzed
1711 -- Return if type = Any_Type (previous error encountered)
1720 -- If not overloaded, then we know the type, and all that needs doing
1721 -- is to check that this type is compatible with the context.
1727 -- In the overloaded case, we must select the interpretation that
1728 -- is compatible with the context (i.e. the type passed to Resolve)
1730 else
1731 -- Loop through possible interpretations
1736 -- We are only interested in interpretations that are compatible
1737 -- with the expected type, any other interpretations are ignored
1742 Write_Eol;
1745 else
1746 -- First matching interpretation
1754 -- Matching interpretation that is not the first, maybe an
1755 -- error, but there are some cases where preference rules are
1756 -- used to choose between the two possibilities. These and
1757 -- some more obscure cases are handled in Disambiguate.
1759 else
1763 -- Disambiguation has succeeded. Skip the remaining
1764 -- interpretations.
1774 else
1775 -- Before we issue an ambiguity complaint, check for
1776 -- the case of a subprogram call where at least one
1777 -- of the arguments is Any_Type, and if so, suppress
1778 -- the message, since it is a cascaded error.
1782 then
1783 declare
1787 begin
1799 Write_Eol;
1812 then
1817 then
1821 -- Not that special case, so issue message using the
1822 -- flag Ambiguous to control printing of the header
1823 -- message only at the start of an ambiguous set.
1826 Error_Msg_NE
1830 Error_Msg_N
1837 -- By default, the error message refers to the candidate
1838 -- interpretation. But if it is a predefined operator,
1839 -- it is implicitly declared at the declaration of
1840 -- the type of the operand. Recover the sloc of that
1841 -- declaration for the error message.
1847 /= Standard_Standard
1848 then
1853 then
1861 /= Standard_Standard
1862 then
1867 then
1870 else
1877 then
1878 Error_Msg_N
1880 else
1887 -- We have a matching interpretation, Expr_Type is the
1888 -- type from this interpretation, and Seen is the entity.
1890 -- For an operator, just set the entity name. The type will
1891 -- be set by the specific operator resolution routine.
1900 -- For an explicit dereference, attribute reference, range,
1901 -- short-circuit form (which is not an operator node),
1902 -- or a call with a name that is an explicit dereference,
1903 -- there is nothing to be done at this point.
1914 then
1917 -- For procedure or function calls, set the type of the
1918 -- name, and also the entity pointer for the prefix
1924 then
1931 then
1936 -- For all other cases, just set the type of the Name
1938 else
1944 -- Move to next interpretation
1952 -- At this stage Found indicates whether or not an acceptable
1953 -- interpretation exists. If not, then we have an error, except
1954 -- that if the context is Any_Type as a result of some other error,
1955 -- then we suppress the error report.
1960 -- If type we are looking for is Void, then this is the
1961 -- procedure call case, and the error is simply that what
1962 -- we gave is not a procedure name (we think of procedure
1963 -- calls as expressions with types internally, but the user
1964 -- doesn't think of them this way!)
1968 -- Special case message if function used as a procedure
1973 then
1974 Error_Msg_NE
1978 -- Otherwise give general message (not clear what cases
1979 -- this covers, but no harm in providing for them!)
1981 else
1987 -- Otherwise we do have a subexpression with the wrong type
1989 -- Check for the case of an allocator which uses an access
1990 -- type instead of the designated type. This is a common
1991 -- error and we specialize the message, posting an error
1992 -- on the operand of the allocator, complaining that we
1993 -- expected the designated type of the allocator.
1999 then
2003 -- Check for view mismatch on Null in instances, for
2004 -- which the view-swapping mechanism has no identifier.
2010 then
2015 -- Check for an aggregate. Sometimes we can get bogus
2016 -- aggregates from misuse of parentheses, and we are
2017 -- about to complain about the aggregate without even
2018 -- looking inside it.
2020 -- Instead, if we have an aggregate of type Any_Composite,
2021 -- then analyze and resolve the component fields, and then
2022 -- only issue another message if we get no errors doing
2023 -- this (otherwise assume that the errors in the aggregate
2024 -- caused the problem).
2028 then
2029 -- Disable expansion in any case. If there is a type mismatch
2030 -- it may be fatal to try to expand the aggregate. The flag
2031 -- would otherwise be set to false when the error is posted.
2035 declare
2037 -- Check one aggregate, and set Found to True if we
2038 -- have a definite error in any of its elements
2041 -- Check one element of aggregate and set Found to
2042 -- True if we definitely have an error in the element.
2047 begin
2065 ----------------
2066 -- Check_Elmt --
2067 ----------------
2070 begin
2071 -- If we have a nested aggregate, go inside it (to
2072 -- attempt a naked analyze-resolve of the aggregate
2073 -- can cause undesirable cascaded errors). Do not
2074 -- resolve expression if it needs a type from context,
2075 -- as for integer * fixed expression.
2080 else
2085 then
2095 begin
2100 -- If an error message was issued already, Found got reset
2101 -- to True, so if it is still False, issue the standard
2102 -- Wrong_Type message.
2107 then
2108 declare
2110 begin
2116 -- Protected operation: retrieve operation name
2119 else
2129 declare
2133 begin
2144 else
2147 else
2153 Resolution_Failed;
2156 -- Test if we have more than one interpretation for the context
2159 Resolution_Failed;
2162 -- Here we have an acceptable interpretation for the context
2164 else
2165 -- Propagate type information and normalize tree for various
2166 -- predefined operations. If the context only imposes a class of
2167 -- types, rather than a specific type, propagate the actual type
2168 -- downward.
2175 then
2178 -- Any_Fixed is legal in a real context only if a specific
2179 -- fixed point type is imposed. If Norman Cohen can be
2180 -- confused by this, it deserves a separate message.
2184 then
2191 -- A user-defined operator is tranformed into a function call at
2192 -- this point, so that further processing knows that operators are
2193 -- really operators (i.e. are predefined operators). User-defined
2194 -- operators that are intrinsic are just renamings of the predefined
2195 -- ones, and need not be turned into calls either, but if they rename
2196 -- a different operator, we must transform the node accordingly.
2197 -- Instantiations of Unchecked_Conversion are intrinsic but are
2198 -- treated as functions, even if given an operator designator.
2203 then
2209 and then
2211 = N_Subprogram_Renaming_Declaration
2212 then
2215 -- If the node is rewritten, it will be fully resolved in
2216 -- Rewrite_Renamed_Operator.
2226 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2228 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2230 when N_And_Then | N_Or_Else
2231 => Resolve_Short_Circuit (N, Ctx_Type);
2233 when N_Attribute_Reference
2234 => Resolve_Attribute (N, Ctx_Type);
2236 when N_Character_Literal
2237 => Resolve_Character_Literal (N, Ctx_Type);
2239 when N_Conditional_Expression
2240 => Resolve_Conditional_Expression (N, Ctx_Type);
2242 when N_Expanded_Name
2243 => Resolve_Entity_Name (N, Ctx_Type);
2245 when N_Extension_Aggregate
2246 => Resolve_Extension_Aggregate (N, Ctx_Type);
2248 when N_Explicit_Dereference
2249 => Resolve_Explicit_Dereference (N, Ctx_Type);
2251 when N_Function_Call
2252 => Resolve_Call (N, Ctx_Type);
2254 when N_Identifier
2255 => Resolve_Entity_Name (N, Ctx_Type);
2257 when N_In | N_Not_In
2258 => Resolve_Membership_Op (N, Ctx_Type);
2260 when N_Indexed_Component
2261 => Resolve_Indexed_Component (N, Ctx_Type);
2263 when N_Integer_Literal
2264 => Resolve_Integer_Literal (N, Ctx_Type);
2266 when N_Null => Resolve_Null (N, Ctx_Type);
2268 when N_Op_And | N_Op_Or | N_Op_Xor
2269 => Resolve_Logical_Op (N, Ctx_Type);
2271 when N_Op_Eq | N_Op_Ne
2272 => Resolve_Equality_Op (N, Ctx_Type);
2274 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2275 => Resolve_Comparison_Op (N, Ctx_Type);
2277 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2279 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2280 N_Op_Divide | N_Op_Mod | N_Op_Rem
2282 => Resolve_Arithmetic_Op (N, Ctx_Type);
2284 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2286 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2288 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2289 => Resolve_Unary_Op (N, Ctx_Type);
2291 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2293 when N_Procedure_Call_Statement
2294 => Resolve_Call (N, Ctx_Type);
2296 when N_Operator_Symbol
2297 => Resolve_Operator_Symbol (N, Ctx_Type);
2299 when N_Qualified_Expression
2300 => Resolve_Qualified_Expression (N, Ctx_Type);
2302 when N_Raise_xxx_Error
2303 => Set_Etype (N, Ctx_Type);
2305 when N_Range => Resolve_Range (N, Ctx_Type);
2307 when N_Real_Literal
2308 => Resolve_Real_Literal (N, Ctx_Type);
2310 when N_Reference => Resolve_Reference (N, Ctx_Type);
2312 when N_Selected_Component
2313 => Resolve_Selected_Component (N, Ctx_Type);
2315 when N_Slice => Resolve_Slice (N, Ctx_Type);
2317 when N_String_Literal
2318 => Resolve_String_Literal (N, Ctx_Type);
2320 when N_Subprogram_Info
2321 => Resolve_Subprogram_Info (N, Ctx_Type);
2323 when N_Type_Conversion
2324 => Resolve_Type_Conversion (N, Ctx_Type);
2326 when N_Unchecked_Expression =>
2327 Resolve_Unchecked_Expression (N, Ctx_Type);
2329 when N_Unchecked_Type_Conversion =>
2330 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2332 end case;
2334 -- If the subexpression was replaced by a non-subexpression, then
2335 -- all we do is to expand it. The only legitimate case we know of
2336 -- is converting procedure call statement to entry call statements,
2337 -- but there may be others, so we are making this test general.
2339 if Nkind (N) not in N_Subexpr then
2340 Debug_A_Exit ("resolving ", N, " (done)");
2341 Expand (N);
2342 return;
2343 end if;
2345 -- The expression is definitely NOT overloaded at this point, so
2346 -- we reset the Is_Overloaded flag to avoid any confusion when
2347 -- reanalyzing the node.
2349 Set_Is_Overloaded (N, False);
2351 -- Freeze expression type, entity if it is a name, and designated
2352 -- type if it is an allocator (RM 13.14(10,11,13)).
2354 -- Now that the resolution of the type of the node is complete,
2355 -- and we did not detect an error, we can expand this node. We
2356 -- skip the expand call if we are in a default expression, see
2357 -- section "Handling of Default Expressions" in Sem spec.
2359 Debug_A_Exit ("resolving ", N, " (done)");
2361 -- We unconditionally freeze the expression, even if we are in
2362 -- default expression mode (the Freeze_Expression routine tests
2363 -- this flag and only freezes static types if it is set).
2365 Freeze_Expression (N);
2367 -- Now we can do the expansion
2369 Expand (N);
2370 end if;
2371 end Resolve;
2373 -------------
2374 -- Resolve --
2375 -------------
2377 -- Version with check(s) suppressed
2379 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2380 begin
2381 if Suppress = All_Checks then
2382 declare
2383 Svg : constant Suppress_Array := Scope_Suppress;
2384 begin
2385 Scope_Suppress := (others => True);
2386 Resolve (N, Typ);
2387 Scope_Suppress := Svg;
2388 end;
2390 else
2391 declare
2392 Svg : constant Boolean := Scope_Suppress (Suppress);
2393 begin
2394 Scope_Suppress (Suppress) := True;
2395 Resolve (N, Typ);
2396 Scope_Suppress (Suppress) := Svg;
2397 end;
2398 end if;
2399 end Resolve;
2401 -------------
2402 -- Resolve --
2403 -------------
2405 -- Version with implicit type
2407 procedure Resolve (N : Node_Id) is
2408 begin
2409 Resolve (N, Etype (N));
2410 end Resolve;
2412 ---------------------
2413 -- Resolve_Actuals --
2414 ---------------------
2416 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2417 Loc : constant Source_Ptr := Sloc (N);
2418 A : Node_Id;
2419 F : Entity_Id;
2420 A_Typ : Entity_Id;
2421 F_Typ : Entity_Id;
2422 Prev : Node_Id := Empty;
2424 procedure Insert_Default;
2425 -- If the actual is missing in a call, insert in the actuals list
2426 -- an instance of the default expression. The insertion is always
2427 -- a named association.
2429 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean;
2430 -- Check whether T1 and T2, or their full views, are derived from a
2431 -- common type. Used to enforce the restrictions on array conversions
2432 -- of AI95-00246.
2434 --------------------
2435 -- Insert_Default --
2436 --------------------
2438 procedure Insert_Default is
2439 Actval : Node_Id;
2440 Assoc : Node_Id;
2442 begin
2443 -- Missing argument in call, nothing to insert
2445 if No (Default_Value (F)) then
2446 return;
2448 else
2449 -- Note that we do a full New_Copy_Tree, so that any associated
2450 -- Itypes are properly copied. This may not be needed any more,
2451 -- but it does no harm as a safety measure! Defaults of a generic
2452 -- formal may be out of bounds of the corresponding actual (see
2453 -- cc1311b) and an additional check may be required.
2455 Actval := New_Copy_Tree (Default_Value (F),
2456 New_Scope => Current_Scope, New_Sloc => Loc);
2458 if Is_Concurrent_Type (Scope (Nam))
2459 and then Has_Discriminants (Scope (Nam))
2460 then
2461 Replace_Actual_Discriminants (N, Actval);
2462 end if;
2464 if Is_Overloadable (Nam)
2465 and then Present (Alias (Nam))
2466 then
2467 if Base_Type (Etype (F)) /= Base_Type (Etype (Actval))
2468 and then not Is_Tagged_Type (Etype (F))
2469 then
2470 -- If default is a real literal, do not introduce a
2471 -- conversion whose effect may depend on the run-time
2472 -- size of universal real.
2474 if Nkind (Actval) = N_Real_Literal then
2475 Set_Etype (Actval, Base_Type (Etype (F)));
2476 else
2477 Actval := Unchecked_Convert_To (Etype (F), Actval);
2478 end if;
2479 end if;
2481 if Is_Scalar_Type (Etype (F)) then
2482 Enable_Range_Check (Actval);
2483 end if;
2485 Set_Parent (Actval, N);
2487 -- Resolve aggregates with their base type, to avoid scope
2488 -- anomalies: the subtype was first built in the suprogram
2489 -- declaration, and the current call may be nested.
2491 if Nkind (Actval) = N_Aggregate
2492 and then Has_Discriminants (Etype (Actval))
2493 then
2494 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
2495 else
2496 Analyze_And_Resolve (Actval, Etype (Actval));
2497 end if;
2499 else
2500 Set_Parent (Actval, N);
2502 -- See note above concerning aggregates
2504 if Nkind (Actval) = N_Aggregate
2505 and then Has_Discriminants (Etype (Actval))
2506 then
2507 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
2509 -- Resolve entities with their own type, which may differ
2510 -- from the type of a reference in a generic context (the
2511 -- view swapping mechanism did not anticipate the re-analysis
2512 -- of default values in calls).
2514 elsif Is_Entity_Name (Actval) then
2515 Analyze_And_Resolve (Actval, Etype (Entity (Actval)));
2517 else
2518 Analyze_And_Resolve (Actval, Etype (Actval));
2519 end if;
2520 end if;
2522 -- If default is a tag indeterminate function call, propagate
2523 -- tag to obtain proper dispatching.
2525 if Is_Controlling_Formal (F)
2526 and then Nkind (Default_Value (F)) = N_Function_Call
2527 then
2528 Set_Is_Controlling_Actual (Actval);
2529 end if;
2531 end if;
2533 -- If the default expression raises constraint error, then just
2534 -- silently replace it with an N_Raise_Constraint_Error node,
2535 -- since we already gave the warning on the subprogram spec.
2537 if Raises_Constraint_Error (Actval) then
2538 Rewrite (Actval,
2539 Make_Raise_Constraint_Error (Loc,
2540 Reason => CE_Range_Check_Failed));
2541 Set_Raises_Constraint_Error (Actval);
2542 Set_Etype (Actval, Etype (F));
2543 end if;
2545 Assoc :=
2546 Make_Parameter_Association (Loc,
2547 Explicit_Actual_Parameter => Actval,
2548 Selector_Name => Make_Identifier (Loc, Chars (F)));
2550 -- Case of insertion is first named actual
2552 if No (Prev) or else
2553 Nkind (Parent (Prev)) /= N_Parameter_Association
2554 then
2555 Set_Next_Named_Actual (Assoc, First_Named_Actual (N));
2556 Set_First_Named_Actual (N, Actval);
2558 if No (Prev) then
2559 if No (Parameter_Associations (N)) then
2560 Set_Parameter_Associations (N, New_List (Assoc));
2561 else
2562 Append (Assoc, Parameter_Associations (N));
2563 end if;
2565 else
2566 Insert_After (Prev, Assoc);
2567 end if;
2569 -- Case of insertion is not first named actual
2571 else
2572 Set_Next_Named_Actual
2573 (Assoc, Next_Named_Actual (Parent (Prev)));
2574 Set_Next_Named_Actual (Parent (Prev), Actval);
2575 Append (Assoc, Parameter_Associations (N));
2576 end if;
2578 Mark_Rewrite_Insertion (Assoc);
2579 Mark_Rewrite_Insertion (Actval);
2581 Prev := Actval;
2582 end Insert_Default;
2584 -------------------
2585 -- Same_Ancestor --
2586 -------------------
2588 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean is
2589 FT1 : Entity_Id := T1;
2590 FT2 : Entity_Id := T2;
2592 begin
2593 if Is_Private_Type (T1)
2594 and then Present (Full_View (T1))
2595 then
2596 FT1 := Full_View (T1);
2597 end if;
2599 if Is_Private_Type (T2)
2600 and then Present (Full_View (T2))
2601 then
2602 FT2 := Full_View (T2);
2603 end if;
2605 return Root_Type (Base_Type (FT1)) = Root_Type (Base_Type (FT2));
2606 end Same_Ancestor;
2608 -- Start of processing for Resolve_Actuals
2610 begin
2611 A := First_Actual (N);
2612 F := First_Formal (Nam);
2613 while Present (F) loop
2614 if No (A) and then Needs_No_Actuals (Nam) then
2615 null;
2617 -- If we have an error in any actual or formal, indicated by
2618 -- a type of Any_Type, then abandon resolution attempt, and
2619 -- set result type to Any_Type.
2621 elsif (Present (A) and then Etype (A) = Any_Type)
2622 or else Etype (F) = Any_Type
2623 then
2624 Set_Etype (N, Any_Type);
2625 return;
2626 end if;
2628 if Present (A)
2629 and then (Nkind (Parent (A)) /= N_Parameter_Association
2630 or else
2631 Chars (Selector_Name (Parent (A))) = Chars (F))
2632 then
2633 -- If the formal is Out or In_Out, do not resolve and expand the
2634 -- conversion, because it is subsequently expanded into explicit
2635 -- temporaries and assignments. However, the object of the
2636 -- conversion can be resolved. An exception is the case of tagged
2637 -- type conversion with a class-wide actual. In that case we want
2638 -- the tag check to occur and no temporary will be needed (no
2639 -- representation change can occur) and the parameter is passed by
2640 -- reference, so we go ahead and resolve the type conversion.
2641 -- Another exception is the case of reference to component or
2642 -- subcomponent of a bit-packed array, in which case we want to
2643 -- defer expansion to the point the in and out assignments are
2644 -- performed.
2646 if Ekind (F) /= E_In_Parameter
2647 and then Nkind (A) = N_Type_Conversion
2648 and then not Is_Class_Wide_Type (Etype (Expression (A)))
2649 then
2650 if Ekind (F) = E_In_Out_Parameter
2651 and then Is_Array_Type (Etype (F))
2652 then
2653 if Has_Aliased_Components (Etype (Expression (A)))
2654 /= Has_Aliased_Components (Etype (F))
2655 then
2656 if Ada_Version < Ada_05 then
2657 Error_Msg_N
2658 ("both component types in a view conversion must be"
2659 & " aliased, or neither", A);
2661 -- Ada 2005: rule is relaxed (see AI-363)
2663 elsif Has_Aliased_Components (Etype (F))
2664 and then
2665 not Has_Aliased_Components (Etype (Expression (A)))
2666 then
2667 Error_Msg_N
2668 ("view conversion operand must have aliased " &
2669 "components", N);
2670 Error_Msg_N
2672 end if;
2674 elsif not Same_Ancestor (Etype (F), Etype (Expression (A)))
2675 and then
2676 (Is_By_Reference_Type (Etype (F))
2677 or else Is_By_Reference_Type (Etype (Expression (A))))
2678 then
2679 Error_Msg_N
2680 ("view conversion between unrelated by reference " &
2682 end if;
2683 end if;
2685 if (Conversion_OK (A)
2686 or else Valid_Conversion (A, Etype (A), Expression (A)))
2687 and then not Is_Ref_To_Bit_Packed_Array (Expression (A))
2688 then
2689 Resolve (Expression (A));
2690 end if;
2692 else
2693 if Nkind (A) = N_Type_Conversion
2694 and then Is_Array_Type (Etype (F))
2695 and then not Same_Ancestor (Etype (F), Etype (Expression (A)))
2696 and then
2697 (Is_Limited_Type (Etype (F))
2698 or else Is_Limited_Type (Etype (Expression (A))))
2699 then
2700 Error_Msg_N
2704 if Is_Limited_Type (Etype (F)) then
2705 Explain_Limited_Type (Etype (F), A);
2706 end if;
2708 if Is_Limited_Type (Etype (Expression (A))) then
2709 Explain_Limited_Type (Etype (Expression (A)), A);
2710 end if;
2711 end if;
2713 -- (Ada 2005: AI-251): If the actual is an allocator whose
2714 -- directly designated type is a class-wide interface, we build
2715 -- an anonymous access type to use it as the type of the
2716 -- allocator. Later, when the subprogram call is expanded, if
2717 -- the interface has a secondary dispatch table the expander
2718 -- will add a type conversion to force the correct displacement
2719 -- of the pointer.
2721 if Nkind (A) = N_Allocator then
2722 declare
2723 DDT : constant Entity_Id :=
2724 Directly_Designated_Type (Base_Type (Etype (F)));
2725 New_Itype : Entity_Id;
2726 begin
2727 if Is_Class_Wide_Type (DDT)
2728 and then Is_Interface (DDT)
2729 then
2730 New_Itype := Create_Itype (E_Anonymous_Access_Type, A);
2731 Set_Etype (New_Itype, Etype (A));
2732 Init_Size_Align (New_Itype);
2733 Set_Directly_Designated_Type (New_Itype,
2734 Directly_Designated_Type (Etype (A)));
2735 Set_Etype (A, New_Itype);
2736 end if;
2737 end;
2738 end if;
2740 Resolve (A, Etype (F));
2741 end if;
2743 A_Typ := Etype (A);
2744 F_Typ := Etype (F);
2746 -- Perform error checks for IN and IN OUT parameters
2748 if Ekind (F) /= E_Out_Parameter then
2750 -- Check unset reference. For scalar parameters, it is clearly
2751 -- wrong to pass an uninitialized value as either an IN or
2752 -- IN-OUT parameter. For composites, it is also clearly an
2753 -- error to pass a completely uninitialized value as an IN
2754 -- parameter, but the case of IN OUT is trickier. We prefer
2755 -- not to give a warning here. For example, suppose there is
2756 -- a routine that sets some component of a record to False.
2757 -- It is perfectly reasonable to make this IN-OUT and allow
2758 -- either initialized or uninitialized records to be passed
2759 -- in this case.
2761 -- For partially initialized composite values, we also avoid
2762 -- warnings, since it is quite likely that we are passing a
2763 -- partially initialized value and only the initialized fields
2764 -- will in fact be read in the subprogram.
2766 if Is_Scalar_Type (A_Typ)
2767 or else (Ekind (F) = E_In_Parameter
2768 and then not Is_Partially_Initialized_Type (A_Typ))
2769 then
2770 Check_Unset_Reference (A);
2771 end if;
2773 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
2774 -- actual to a nested call, since this is case of reading an
2775 -- out parameter, which is not allowed.
2777 if Ada_Version = Ada_83
2778 and then Is_Entity_Name (A)
2779 and then Ekind (Entity (A)) = E_Out_Parameter
2780 then
2782 end if;
2783 end if;
2785 if Ekind (F) /= E_In_Parameter
2786 and then not Is_OK_Variable_For_Out_Formal (A)
2787 then
2790 if Is_Entity_Name (A) then
2791 Kill_Checks (Entity (A));
2792 else
2793 Kill_All_Checks;
2794 end if;
2795 end if;
2797 if Etype (A) = Any_Type then
2798 Set_Etype (N, Any_Type);
2799 return;
2800 end if;
2802 -- Apply appropriate range checks for in, out, and in-out
2803 -- parameters. Out and in-out parameters also need a separate
2804 -- check, if there is a type conversion, to make sure the return
2805 -- value meets the constraints of the variable before the
2806 -- conversion.
2808 -- Gigi looks at the check flag and uses the appropriate types.
2809 -- For now since one flag is used there is an optimization which
2810 -- might not be done in the In Out case since Gigi does not do
2811 -- any analysis. More thought required about this ???
2813 if Ekind (F) = E_In_Parameter
2814 or else Ekind (F) = E_In_Out_Parameter
2815 then
2816 if Is_Scalar_Type (Etype (A)) then
2817 Apply_Scalar_Range_Check (A, F_Typ);
2819 elsif Is_Array_Type (Etype (A)) then
2820 Apply_Length_Check (A, F_Typ);
2822 elsif Is_Record_Type (F_Typ)
2823 and then Has_Discriminants (F_Typ)
2824 and then Is_Constrained (F_Typ)
2825 and then (not Is_Derived_Type (F_Typ)
2826 or else Comes_From_Source (Nam))
2827 then
2828 Apply_Discriminant_Check (A, F_Typ);
2830 elsif Is_Access_Type (F_Typ)
2831 and then Is_Array_Type (Designated_Type (F_Typ))
2832 and then Is_Constrained (Designated_Type (F_Typ))
2833 then
2834 Apply_Length_Check (A, F_Typ);
2836 elsif Is_Access_Type (F_Typ)
2837 and then Has_Discriminants (Designated_Type (F_Typ))
2838 and then Is_Constrained (Designated_Type (F_Typ))
2839 then
2840 Apply_Discriminant_Check (A, F_Typ);
2842 else
2843 Apply_Range_Check (A, F_Typ);
2844 end if;
2846 -- Ada 2005 (AI-231)
2848 if Ada_Version >= Ada_05
2849 and then Is_Access_Type (F_Typ)
2850 and then Can_Never_Be_Null (F_Typ)
2851 and then Nkind (A) = N_Null
2852 then
2853 Apply_Compile_Time_Constraint_Error
2854 (N => A,
2857 Reason => CE_Null_Not_Allowed);
2858 end if;
2859 end if;
2861 if Ekind (F) = E_Out_Parameter
2862 or else Ekind (F) = E_In_Out_Parameter
2863 then
2864 if Nkind (A) = N_Type_Conversion then
2865 if Is_Scalar_Type (A_Typ) then
2866 Apply_Scalar_Range_Check
2867 (Expression (A), Etype (Expression (A)), A_Typ);
2868 else
2869 Apply_Range_Check
2870 (Expression (A), Etype (Expression (A)), A_Typ);
2871 end if;
2873 else
2874 if Is_Scalar_Type (F_Typ) then
2875 Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
2877 elsif Is_Array_Type (F_Typ)
2878 and then Ekind (F) = E_Out_Parameter
2879 then
2880 Apply_Length_Check (A, F_Typ);
2882 else
2883 Apply_Range_Check (A, A_Typ, F_Typ);
2884 end if;
2885 end if;
2886 end if;
2888 -- An actual associated with an access parameter is implicitly
2889 -- converted to the anonymous access type of the formal and
2890 -- must satisfy the legality checks for access conversions.
2892 if Ekind (F_Typ) = E_Anonymous_Access_Type then
2893 if not Valid_Conversion (A, F_Typ, A) then
2894 Error_Msg_N
2896 end if;
2897 end if;
2899 -- Check bad case of atomic/volatile argument (RM C.6(12))
2901 if Is_By_Reference_Type (Etype (F))
2902 and then Comes_From_Source (N)
2903 then
2904 if Is_Atomic_Object (A)
2905 and then not Is_Atomic (Etype (F))
2906 then
2907 Error_Msg_N
2909 N);
2911 elsif Is_Volatile_Object (A)
2912 and then not Is_Volatile (Etype (F))
2913 then
2914 Error_Msg_N
2916 N);
2917 end if;
2918 end if;
2920 -- Check that subprograms don't have improper controlling
2921 -- arguments (RM 3.9.2 (9))
2923 if Is_Controlling_Formal (F) then
2924 Set_Is_Controlling_Actual (A);
2925 elsif Nkind (A) = N_Explicit_Dereference then
2926 Validate_Remote_Access_To_Class_Wide_Type (A);
2927 end if;
2929 if (Is_Class_Wide_Type (A_Typ) or else Is_Dynamically_Tagged (A))
2930 and then not Is_Class_Wide_Type (F_Typ)
2931 and then not Is_Controlling_Formal (F)
2932 then
2935 if Is_Subprogram (Nam)
2936 and then Comes_From_Source (Nam)
2937 then
2938 Error_Msg_Node_2 := F_Typ;
2939 Error_Msg_NE
2941 end if;
2943 elsif Is_Access_Type (A_Typ)
2944 and then Is_Access_Type (F_Typ)
2945 and then Ekind (F_Typ) /= E_Access_Subprogram_Type
2946 and then (Is_Class_Wide_Type (Designated_Type (A_Typ))
2947 or else (Nkind (A) = N_Attribute_Reference
2948 and then
2949 Is_Class_Wide_Type (Etype (Prefix (A)))))
2950 and then not Is_Class_Wide_Type (Designated_Type (F_Typ))
2951 and then not Is_Controlling_Formal (F)
2952 then
2953 Error_Msg_N
2956 if Is_Subprogram (Nam)
2957 and then Comes_From_Source (Nam)
2958 then
2959 Error_Msg_Node_2 := Designated_Type (F_Typ);
2960 Error_Msg_NE
2962 end if;
2963 end if;
2965 Eval_Actual (A);
2967 -- If it is a named association, treat the selector_name as
2968 -- a proper identifier, and mark the corresponding entity.
2970 if Nkind (Parent (A)) = N_Parameter_Association then
2971 Set_Entity (Selector_Name (Parent (A)), F);
2972 Generate_Reference (F, Selector_Name (Parent (A)));
2973 Set_Etype (Selector_Name (Parent (A)), F_Typ);
2974 Generate_Reference (F_Typ, N, ' ');
2975 end if;
2977 Prev := A;
2979 if Ekind (F) /= E_Out_Parameter then
2980 Check_Unset_Reference (A);
2981 end if;
2983 Next_Actual (A);
2985 -- Case where actual is not present
2987 else
2988 Insert_Default;
2989 end if;
2991 Next_Formal (F);
2992 end loop;
2993 end Resolve_Actuals;
2995 -----------------------
2996 -- Resolve_Allocator --
2997 -----------------------
2999 procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id) is
3000 E : constant Node_Id := Expression (N);
3001 Subtyp : Entity_Id;
3002 Discrim : Entity_Id;
3003 Constr : Node_Id;
3004 Disc_Exp : Node_Id;
3006 function In_Dispatching_Context return Boolean;
3007 -- If the allocator is an actual in a call, it is allowed to be
3008 -- class-wide when the context is not because it is a controlling
3009 -- actual.
3011 ----------------------------
3012 -- In_Dispatching_Context --
3013 ----------------------------
3015 function In_Dispatching_Context return Boolean is
3016 Par : constant Node_Id := Parent (N);
3018 begin
3019 return (Nkind (Par) = N_Function_Call
3020 or else Nkind (Par) = N_Procedure_Call_Statement)
3021 and then Is_Entity_Name (Name (Par))
3022 and then Is_Dispatching_Operation (Entity (Name (Par)));
3023 end In_Dispatching_Context;
3025 -- Start of processing for Resolve_Allocator
3027 begin
3028 -- Replace general access with specific type
3030 if Ekind (Etype (N)) = E_Allocator_Type then
3031 Set_Etype (N, Base_Type (Typ));
3032 end if;
3034 if Is_Abstract (Typ) then
3036 end if;
3038 -- For qualified expression, resolve the expression using the
3039 -- given subtype (nothing to do for type mark, subtype indication)
3041 if Nkind (E) = N_Qualified_Expression then
3042 if Is_Class_Wide_Type (Etype (E))
3043 and then not Is_Class_Wide_Type (Designated_Type (Typ))
3044 and then not In_Dispatching_Context
3045 then
3046 Error_Msg_N
3048 end if;
3050 Resolve (Expression (E), Etype (E));
3051 Check_Unset_Reference (Expression (E));
3053 -- A qualified expression requires an exact match of the type,
3054 -- class-wide matching is not allowed.
3056 if (Is_Class_Wide_Type (Etype (Expression (E)))
3057 or else Is_Class_Wide_Type (Etype (E)))
3058 and then Base_Type (Etype (Expression (E))) /= Base_Type (Etype (E))
3059 then
3060 Wrong_Type (Expression (E), Etype (E));
3061 end if;
3063 -- For a subtype mark or subtype indication, freeze the subtype
3065 else
3066 Freeze_Expression (E);
3068 if Is_Access_Constant (Typ) and then not No_Initialization (N) then
3069 Error_Msg_N
3071 end if;
3073 -- A special accessibility check is needed for allocators that
3074 -- constrain access discriminants. The level of the type of the
3075 -- expression used to contrain an access discriminant cannot be
3076 -- deeper than the type of the allocator (in constrast to access
3077 -- parameters, where the level of the actual can be arbitrary).
3078 -- We can't use Valid_Conversion to perform this check because
3079 -- in general the type of the allocator is unrelated to the type
3080 -- of the access discriminant. Note that specialized checks are
3081 -- needed for the cases of a constraint expression which is an
3082 -- access attribute or an access discriminant.
3084 if Nkind (Original_Node (E)) = N_Subtype_Indication
3085 and then Ekind (Typ) /= E_Anonymous_Access_Type
3086 then
3087 Subtyp := Entity (Subtype_Mark (Original_Node (E)));
3089 if Has_Discriminants (Subtyp) then
3090 Discrim := First_Discriminant (Base_Type (Subtyp));
3091 Constr := First (Constraints (Constraint (Original_Node (E))));
3092 while Present (Discrim) and then Present (Constr) loop
3093 if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
3094 if Nkind (Constr) = N_Discriminant_Association then
3095 Disc_Exp := Original_Node (Expression (Constr));
3096 else
3097 Disc_Exp := Original_Node (Constr);
3098 end if;
3100 if Type_Access_Level (Etype (Disc_Exp))
3101 > Type_Access_Level (Typ)
3102 then
3103 Error_Msg_N
3105 Disc_Exp);
3107 elsif Nkind (Disc_Exp) = N_Attribute_Reference
3108 and then Get_Attribute_Id (Attribute_Name (Disc_Exp))
3109 = Attribute_Access
3110 and then Object_Access_Level (Prefix (Disc_Exp))
3111 > Type_Access_Level (Typ)
3112 then
3113 Error_Msg_N
3117 -- When the operand is an access discriminant the check
3118 -- is against the level of the prefix object.
3120 elsif Ekind (Etype (Disc_Exp)) = E_Anonymous_Access_Type
3121 and then Nkind (Disc_Exp) = N_Selected_Component
3122 and then Object_Access_Level (Prefix (Disc_Exp))
3123 > Type_Access_Level (Typ)
3124 then
3125 Error_Msg_N
3128 end if;
3129 end if;
3130 Next_Discriminant (Discrim);
3131 Next (Constr);
3132 end loop;
3133 end if;
3134 end if;
3135 end if;
3137 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
3138 -- check that the level of the type of the created object is not deeper
3139 -- than the level of the allocator's access type, since extensions can
3140 -- now occur at deeper levels than their ancestor types. This is a
3141 -- static accessibility level check; a run-time check is also needed in
3142 -- the case of an initialized allocator with a class-wide argument (see
3143 -- Expand_Allocator_Expression).
3145 if Ada_Version >= Ada_05
3146 and then Is_Class_Wide_Type (Designated_Type (Typ))
3147 then
3148 declare
3149 Exp_Typ : Entity_Id;
3151 begin
3152 if Nkind (E) = N_Qualified_Expression then
3153 Exp_Typ := Etype (E);
3154 elsif Nkind (E) = N_Subtype_Indication then
3155 Exp_Typ := Entity (Subtype_Mark (Original_Node (E)));
3156 else
3157 Exp_Typ := Entity (E);
3158 end if;
3160 if Type_Access_Level (Exp_Typ) > Type_Access_Level (Typ) then
3161 if In_Instance_Body then
3165 E);
3166 Rewrite (N,
3167 Make_Raise_Program_Error (Sloc (N),
3168 Reason => PE_Accessibility_Check_Failed));
3169 Set_Etype (N, Typ);
3170 else
3173 end if;
3174 end if;
3175 end;
3176 end if;
3178 -- Check for allocation from an empty storage pool
3180 if No_Pool_Assigned (Typ) then
3181 declare
3182 Loc : constant Source_Ptr := Sloc (N);
3183 begin
3186 Insert_Action (N,
3187 Make_Raise_Storage_Error (Loc,
3188 Reason => SE_Empty_Storage_Pool));
3189 end;
3191 -- If the context is an unchecked conversion, as may happen within
3192 -- an inlined subprogram, the allocator is being resolved with its
3193 -- own anonymous type. In that case, if the target type has a specific
3194 -- storage pool, it must be inherited explicitly by the allocator type.
3196 elsif Nkind (Parent (N)) = N_Unchecked_Type_Conversion
3197 and then No (Associated_Storage_Pool (Typ))
3198 then
3199 Set_Associated_Storage_Pool
3200 (Typ, Associated_Storage_Pool (Etype (Parent (N))));
3201 end if;
3202 end Resolve_Allocator;
3204 ---------------------------
3205 -- Resolve_Arithmetic_Op --
3206 ---------------------------
3208 -- Used for resolving all arithmetic operators except exponentiation
3210 procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id) is
3211 L : constant Node_Id := Left_Opnd (N);
3212 R : constant Node_Id := Right_Opnd (N);
3213 TL : constant Entity_Id := Base_Type (Etype (L));
3214 TR : constant Entity_Id := Base_Type (Etype (R));
3215 T : Entity_Id;
3216 Rop : Node_Id;
3218 B_Typ : constant Entity_Id := Base_Type (Typ);
3219 -- We do the resolution using the base type, because intermediate values
3220 -- in expressions always are of the base type, not a subtype of it.
3222 function Is_Integer_Or_Universal (N : Node_Id) return Boolean;
3223 -- Return True iff given type is Integer or universal real/integer
3225 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id);
3226 -- Choose type of integer literal in fixed-point operation to conform
3227 -- to available fixed-point type. T is the type of the other operand,
3228 -- which is needed to determine the expected type of N.
3230 procedure Set_Operand_Type (N : Node_Id);
3231 -- Set operand type to T if universal
3233 -----------------------------
3234 -- Is_Integer_Or_Universal --
3235 -----------------------------
3237 function Is_Integer_Or_Universal (N : Node_Id) return Boolean is
3238 T : Entity_Id;
3239 Index : Interp_Index;
3240 It : Interp;
3242 begin
3243 if not Is_Overloaded (N) then
3244 T := Etype (N);
3245 return Base_Type (T) = Base_Type (Standard_Integer)
3246 or else T = Universal_Integer
3247 or else T = Universal_Real;
3248 else
3249 Get_First_Interp (N, Index, It);
3250 while Present (It.Typ) loop
3251 if Base_Type (It.Typ) = Base_Type (Standard_Integer)
3252 or else It.Typ = Universal_Integer
3253 or else It.Typ = Universal_Real
3254 then
3255 return True;
3256 end if;
3258 Get_Next_Interp (Index, It);
3259 end loop;
3260 end if;
3262 return False;
3263 end Is_Integer_Or_Universal;
3265 ----------------------------
3266 -- Set_Mixed_Mode_Operand --
3267 ----------------------------
3269 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id) is
3270 Index : Interp_Index;
3271 It : Interp;
3273 begin
3274 if Universal_Interpretation (N) = Universal_Integer then
3276 -- A universal integer literal is resolved as standard integer
3277 -- except in the case of a fixed-point result, where we leave it
3278 -- as universal (to be handled by Exp_Fixd later on)
3280 if Is_Fixed_Point_Type (T) then
3281 Resolve (N, Universal_Integer);
3282 else
3283 Resolve (N, Standard_Integer);
3284 end if;
3286 elsif Universal_Interpretation (N) = Universal_Real
3287 and then (T = Base_Type (Standard_Integer)
3288 or else T = Universal_Integer
3289 or else T = Universal_Real)
3290 then
3291 -- A universal real can appear in a fixed-type context. We resolve
3292 -- the literal with that context, even though this might raise an
3293 -- exception prematurely (the other operand may be zero).
3295 Resolve (N, B_Typ);
3297 elsif Etype (N) = Base_Type (Standard_Integer)
3298 and then T = Universal_Real
3299 and then Is_Overloaded (N)
3300 then
3301 -- Integer arg in mixed-mode operation. Resolve with universal
3302 -- type, in case preference rule must be applied.
3304 Resolve (N, Universal_Integer);
3306 elsif Etype (N) = T
3307 and then B_Typ /= Universal_Fixed
3308 then
3309 -- Not a mixed-mode operation, resolve with context
3311 Resolve (N, B_Typ);
3313 elsif Etype (N) = Any_Fixed then
3315 -- N may itself be a mixed-mode operation, so use context type
3317 Resolve (N, B_Typ);
3319 elsif Is_Fixed_Point_Type (T)
3320 and then B_Typ = Universal_Fixed
3321 and then Is_Overloaded (N)
3322 then
3323 -- Must be (fixed * fixed) operation, operand must have one
3324 -- compatible interpretation.
3326 Resolve (N, Any_Fixed);
3328 elsif Is_Fixed_Point_Type (B_Typ)
3329 and then (T = Universal_Real
3330 or else Is_Fixed_Point_Type (T))
3331 and then Is_Overloaded (N)
3332 then
3333 -- C * F(X) in a fixed context, where C is a real literal or a
3334 -- fixed-point expression. F must have either a fixed type
3335 -- interpretation or an integer interpretation, but not both.
3337 Get_First_Interp (N, Index, It);
3338 while Present (It.Typ) loop
3339 if Base_Type (It.Typ) = Base_Type (Standard_Integer) then
3341 if Analyzed (N) then
3343 else
3344 Resolve (N, Standard_Integer);
3345 end if;
3347 elsif Is_Fixed_Point_Type (It.Typ) then
3349 if Analyzed (N) then
3351 else
3352 Resolve (N, It.Typ);
3353 end if;
3354 end if;
3356 Get_Next_Interp (Index, It);
3357 end loop;
3359 -- Reanalyze the literal with the fixed type of the context. If
3360 -- context is Universal_Fixed, we are within a conversion, leave
3361 -- the literal as a universal real because there is no usable
3362 -- fixed type, and the target of the conversion plays no role in
3363 -- the resolution.
3365 declare
3366 Op2 : Node_Id;
3367 T2 : Entity_Id;
3369 begin
3370 if N = L then
3371 Op2 := R;
3372 else
3373 Op2 := L;
3374 end if;
3376 if B_Typ = Universal_Fixed
3377 and then Nkind (Op2) = N_Real_Literal
3378 then
3379 T2 := Universal_Real;
3380 else
3381 T2 := B_Typ;
3382 end if;
3384 Set_Analyzed (Op2, False);
3385 Resolve (Op2, T2);
3386 end;
3388 else
3389 Resolve (N);
3390 end if;
3391 end Set_Mixed_Mode_Operand;
3393 ----------------------
3394 -- Set_Operand_Type --
3395 ----------------------
3397 procedure Set_Operand_Type (N : Node_Id) is
3398 begin
3399 if Etype (N) = Universal_Integer
3400 or else Etype (N) = Universal_Real
3401 then
3402 Set_Etype (N, T);
3403 end if;
3404 end Set_Operand_Type;
3406 -- Start of processing for Resolve_Arithmetic_Op
3408 begin
3409 if Comes_From_Source (N)
3410 and then Ekind (Entity (N)) = E_Function
3411 and then Is_Imported (Entity (N))
3412 and then Is_Intrinsic_Subprogram (Entity (N))
3413 then
3414 Resolve_Intrinsic_Operator (N, Typ);
3415 return;
3417 -- Special-case for mixed-mode universal expressions or fixed point
3418 -- type operation: each argument is resolved separately. The same
3419 -- treatment is required if one of the operands of a fixed point
3420 -- operation is universal real, since in this case we don't do a
3421 -- conversion to a specific fixed-point type (instead the expander
3422 -- takes care of the case).
3424 elsif (B_Typ = Universal_Integer
3425 or else B_Typ = Universal_Real)
3426 and then Present (Universal_Interpretation (L))
3427 and then Present (Universal_Interpretation (R))
3428 then
3429 Resolve (L, Universal_Interpretation (L));
3430 Resolve (R, Universal_Interpretation (R));
3431 Set_Etype (N, B_Typ);
3433 elsif (B_Typ = Universal_Real
3434 or else Etype (N) = Universal_Fixed
3435 or else (Etype (N) = Any_Fixed
3436 and then Is_Fixed_Point_Type (B_Typ))
3437 or else (Is_Fixed_Point_Type (B_Typ)
3438 and then (Is_Integer_Or_Universal (L)
3439 or else
3440 Is_Integer_Or_Universal (R))))
3441 and then (Nkind (N) = N_Op_Multiply or else
3442 Nkind (N) = N_Op_Divide)
3443 then
3444 if TL = Universal_Integer or else TR = Universal_Integer then
3445 Check_For_Visible_Operator (N, B_Typ);
3446 end if;
3448 -- If context is a fixed type and one operand is integer, the
3449 -- other is resolved with the type of the context.
3451 if Is_Fixed_Point_Type (B_Typ)
3452 and then (Base_Type (TL) = Base_Type (Standard_Integer)
3453 or else TL = Universal_Integer)
3454 then
3455 Resolve (R, B_Typ);
3456 Resolve (L, TL);
3458 elsif Is_Fixed_Point_Type (B_Typ)
3459 and then (Base_Type (TR) = Base_Type (Standard_Integer)
3460 or else TR = Universal_Integer)
3461 then
3462 Resolve (L, B_Typ);
3463 Resolve (R, TR);
3465 else
3466 Set_Mixed_Mode_Operand (L, TR);
3467 Set_Mixed_Mode_Operand (R, TL);
3468 end if;
3470 if Etype (N) = Universal_Fixed
3471 or else Etype (N) = Any_Fixed
3472 then
3473 if B_Typ = Universal_Fixed
3474 and then Nkind (Parent (N)) /= N_Type_Conversion
3475 and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
3476 then
3477 Error_Msg_N
3479 Error_Msg_N
3482 Set_Etype (L, Any_Type);
3483 Set_Etype (R, Any_Type);
3485 else
3486 if Ada_Version = Ada_83
3487 and then Etype (N) = Universal_Fixed
3488 and then Nkind (Parent (N)) /= N_Type_Conversion
3489 and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
3490 then
3491 Error_Msg_N
3494 N);
3495 end if;
3497 Set_Etype (N, B_Typ);
3498 end if;
3500 elsif Is_Fixed_Point_Type (B_Typ)
3501 and then (Is_Integer_Or_Universal (L)
3502 or else Nkind (L) = N_Real_Literal
3503 or else Nkind (R) = N_Real_Literal
3504 or else
3505 Is_Integer_Or_Universal (R))
3506 then
3507 Set_Etype (N, B_Typ);
3509 elsif Etype (N) = Any_Fixed then
3511 -- If no previous errors, this is only possible if one operand
3512 -- is overloaded and the context is universal. Resolve as such.
3514 Set_Etype (N, B_Typ);
3515 end if;
3517 else
3518 if (TL = Universal_Integer or else TL = Universal_Real)
3519 and then (TR = Universal_Integer or else TR = Universal_Real)
3520 then
3521 Check_For_Visible_Operator (N, B_Typ);
3522 end if;
3524 -- If the context is Universal_Fixed and the operands are also
3525 -- universal fixed, this is an error, unless there is only one
3526 -- applicable fixed_point type (usually duration).
3528 if B_Typ = Universal_Fixed
3529 and then Etype (L) = Universal_Fixed
3530 then
3531 T := Unique_Fixed_Point_Type (N);
3533 if T = Any_Type then
3534 Set_Etype (N, T);
3535 return;
3536 else
3537 Resolve (L, T);
3538 Resolve (R, T);
3539 end if;
3541 else
3542 Resolve (L, B_Typ);
3543 Resolve (R, B_Typ);
3544 end if;
3546 -- If one of the arguments was resolved to a non-universal type.
3547 -- label the result of the operation itself with the same type.
3548 -- Do the same for the universal argument, if any.
3550 T := Intersect_Types (L, R);
3551 Set_Etype (N, Base_Type (T));
3552 Set_Operand_Type (L);
3553 Set_Operand_Type (R);
3554 end if;
3556 Generate_Operator_Reference (N, Typ);
3557 Eval_Arithmetic_Op (N);
3559 -- Set overflow and division checking bit. Much cleverer code needed
3560 -- here eventually and perhaps the Resolve routines should be separated
3561 -- for the various arithmetic operations, since they will need
3562 -- different processing. ???
3564 if Nkind (N) in N_Op then
3565 if not Overflow_Checks_Suppressed (Etype (N)) then
3566 Enable_Overflow_Check (N);
3567 end if;
3569 -- Give warning if explicit division by zero
3571 if (Nkind (N) = N_Op_Divide
3572 or else Nkind (N) = N_Op_Rem
3573 or else Nkind (N) = N_Op_Mod)
3574 and then not Division_Checks_Suppressed (Etype (N))
3575 then
3576 Rop := Right_Opnd (N);
3578 if Compile_Time_Known_Value (Rop)
3579 and then ((Is_Integer_Type (Etype (Rop))
3580 and then Expr_Value (Rop) = Uint_0)
3581 or else
3582 (Is_Real_Type (Etype (Rop))
3583 and then Expr_Value_R (Rop) = Ureal_0))
3584 then
3585 Apply_Compile_Time_Constraint_Error
3587 Loc => Sloc (Right_Opnd (N)));
3589 -- Otherwise just set the flag to check at run time
3591 else
3592 Set_Do_Division_Check (N);
3593 end if;
3594 end if;
3595 end if;
3597 Check_Unset_Reference (L);
3598 Check_Unset_Reference (R);
3599 end Resolve_Arithmetic_Op;
3601 ------------------
3602 -- Resolve_Call --
3603 ------------------
3605 procedure Resolve_Call (N : Node_Id; Typ : Entity_Id) is
3606 Loc : constant Source_Ptr := Sloc (N);
3607 Subp : constant Node_Id := Name (N);
3608 Nam : Entity_Id;
3609 I : Interp_Index;
3610 It : Interp;
3611 Norm_OK : Boolean;
3612 Scop : Entity_Id;
3614 begin
3615 -- The context imposes a unique interpretation with type Typ on a
3616 -- procedure or function call. Find the entity of the subprogram that
3617 -- yields the expected type, and propagate the corresponding formal
3618 -- constraints on the actuals. The caller has established that an
3619 -- interpretation exists, and emitted an error if not unique.
3621 -- First deal with the case of a call to an access-to-subprogram,
3622 -- dereference made explicit in Analyze_Call.
3624 if Ekind (Etype (Subp)) = E_Subprogram_Type then
3625 if not Is_Overloaded (Subp) then
3626 Nam := Etype (Subp);
3628 else
3629 -- Find the interpretation whose type (a subprogram type) has a
3630 -- return type that is compatible with the context. Analysis of
3631 -- the node has established that one exists.
3633 Nam := Empty;
3635 Get_First_Interp (Subp, I, It);
3636 while Present (It.Typ) loop
3637 if Covers (Typ, Etype (It.Typ)) then
3638 Nam := It.Typ;
3639 exit;
3640 end if;
3642 Get_Next_Interp (I, It);
3643 end loop;
3645 if No (Nam) then
3646 raise Program_Error;
3647 end if;
3648 end if;
3650 -- If the prefix is not an entity, then resolve it
3652 if not Is_Entity_Name (Subp) then
3653 Resolve (Subp, Nam);
3654 end if;
3656 -- For an indirect call, we always invalidate checks, since we do not
3657 -- know whether the subprogram is local or global. Yes we could do
3658 -- better here, e.g. by knowing that there are no local subprograms,
3659 -- but it does not seem worth the effort. Similarly, we kill al
3660 -- knowledge of current constant values.
3662 Kill_Current_Values;
3664 -- If this is a procedure call which is really an entry call, do the
3665 -- conversion of the procedure call to an entry call. Protected
3666 -- operations use the same circuitry because the name in the call can be
3667 -- an arbitrary expression with special resolution rules.
3669 elsif Nkind (Subp) = N_Selected_Component
3670 or else Nkind (Subp) = N_Indexed_Component
3671 or else (Is_Entity_Name (Subp)
3672 and then Ekind (Entity (Subp)) = E_Entry)
3673 then
3674 Resolve_Entry_Call (N, Typ);
3675 Check_Elab_Call (N);
3677 -- Kill checks and constant values, as above for indirect case
3678 -- Who knows what happens when another task is activated?
3680 Kill_Current_Values;
3681 return;
3683 -- Normal subprogram call with name established in Resolve
3685 elsif not (Is_Type (Entity (Subp))) then
3686 Nam := Entity (Subp);
3687 Set_Entity_With_Style_Check (Subp, Nam);
3688 Generate_Reference (Nam, Subp);
3690 -- Otherwise we must have the case of an overloaded call
3692 else
3693 pragma Assert (Is_Overloaded (Subp));
3694 Nam := Empty; -- We know that it will be assigned in loop below
3696 Get_First_Interp (Subp, I, It);
3697 while Present (It.Typ) loop
3698 if Covers (Typ, It.Typ) then
3699 Nam := It.Nam;
3700 Set_Entity_With_Style_Check (Subp, Nam);
3701 Generate_Reference (Nam, Subp);
3702 exit;
3703 end if;
3705 Get_Next_Interp (I, It);
3706 end loop;
3707 end if;
3709 -- Check that a call to Current_Task does not occur in an entry body
3711 if Is_RTE (Nam, RE_Current_Task) then
3712 declare
3713 P : Node_Id;
3715 begin
3716 P := N;
3717 loop
3718 P := Parent (P);
3719 exit when No (P);
3721 if Nkind (P) = N_Entry_Body then
3722 Error_Msg_NE
3724 N, Nam);
3725 exit;
3726 end if;
3727 end loop;
3728 end;
3729 end if;
3731 -- Cannot call thread body directly
3733 if Is_Thread_Body (Nam) then
3734 Error_Msg_N ("cannot call thread body directly", N);
3735 end if;
3737 -- If the subprogram is not global, then kill all checks. This is a bit
3738 -- conservative, since in many cases we could do better, but it is not
3739 -- worth the effort. Similarly, we kill constant values. However we do
3740 -- not need to do this for internal entities (unless they are inherited
3741 -- user-defined subprograms), since they are not in the business of
3742 -- molesting global values.
3744 if not Is_Library_Level_Entity (Nam)
3745 and then (Comes_From_Source (Nam)
3746 or else (Present (Alias (Nam))
3747 and then Comes_From_Source (Alias (Nam))))
3748 then
3749 Kill_Current_Values;
3750 end if;
3752 -- Check for call to subprogram marked Is_Obsolescent
3754 Check_Obsolescent (Nam, N);
3756 -- Check that a procedure call does not occur in the context of the
3757 -- entry call statement of a conditional or timed entry call. Note that
3758 -- the case of a call to a subprogram renaming of an entry will also be
3759 -- rejected. The test for N not being an N_Entry_Call_Statement is
3760 -- defensive, covering the possibility that the processing of entry
3761 -- calls might reach this point due to later modifications of the code
3762 -- above.
3764 if Nkind (Parent (N)) = N_Entry_Call_Alternative
3765 and then Nkind (N) /= N_Entry_Call_Statement
3766 and then Entry_Call_Statement (Parent (N)) = N
3767 then
3768 if Ada_Version < Ada_05 then
3769 Error_Msg_N ("entry call required in select statement", N);
3771 -- Ada 2005 (AI-345): If a procedure_call_statement is used
3772 -- for a procedure_or_entry_call, the procedure_name or pro-
3773 -- cedure_prefix of the procedure_call_statement shall denote
3774 -- an entry renamed by a procedure, or (a view of) a primitive
3775 -- subprogram of a limited interface whose first parameter is
3776 -- a controlling parameter.
3778 elsif Nkind (N) = N_Procedure_Call_Statement
3779 and then not Is_Renamed_Entry (Nam)
3780 and then not Is_Controlling_Limited_Procedure (Nam)
3781 then
3782 Error_Msg_N
3783 ("entry call or dispatching primitive of interface required", N);
3784 end if;
3785 end if;
3787 -- Check that this is not a call to a protected procedure or
3788 -- entry from within a protected function.
3790 if Ekind (Current_Scope) = E_Function
3791 and then Ekind (Scope (Current_Scope)) = E_Protected_Type
3792 and then Ekind (Nam) /= E_Function
3793 and then Scope (Nam) = Scope (Current_Scope)
3794 then
3795 Error_Msg_N ("within protected function, protected " &
3796 "object is constant", N);
3798 end if;
3800 -- Freeze the subprogram name if not in default expression. Note that we
3801 -- freeze procedure calls as well as function calls. Procedure calls are
3802 -- not frozen according to the rules (RM 13.14(14)) because it is
3803 -- impossible to have a procedure call to a non-frozen procedure in pure
3804 -- Ada, but in the code that we generate in the expander, this rule
3805 -- needs extending because we can generate procedure calls that need
3806 -- freezing.
3808 if Is_Entity_Name (Subp) and then not In_Default_Expression then
3809 Freeze_Expression (Subp);
3810 end if;
3812 -- For a predefined operator, the type of the result is the type imposed
3813 -- by context, except for a predefined operation on universal fixed.
3814 -- Otherwise The type of the call is the type returned by the subprogram
3815 -- being called.
3817 if Is_Predefined_Op (Nam) then
3818 if Etype (N) /= Universal_Fixed then
3819 Set_Etype (N, Typ);
3820 end if;
3822 -- If the subprogram returns an array type, and the context requires the
3823 -- component type of that array type, the node is really an indexing of
3824 -- the parameterless call. Resolve as such. A pathological case occurs
3825 -- when the type of the component is an access to the array type. In
3826 -- this case the call is truly ambiguous.
3828 elsif Needs_No_Actuals (Nam)
3829 and then
3830 ((Is_Array_Type (Etype (Nam))
3831 and then Covers (Typ, Component_Type (Etype (Nam))))
3832 or else (Is_Access_Type (Etype (Nam))
3833 and then Is_Array_Type (Designated_Type (Etype (Nam)))
3834 and then
3835 Covers (Typ,
3836 Component_Type (Designated_Type (Etype (Nam))))))
3837 then
3838 declare
3839 Index_Node : Node_Id;
3840 New_Subp : Node_Id;
3841 Ret_Type : constant Entity_Id := Etype (Nam);
3843 begin
3844 if Is_Access_Type (Ret_Type)
3845 and then Ret_Type = Component_Type (Designated_Type (Ret_Type))
3846 then
3847 Error_Msg_N
3848 ("cannot disambiguate function call and indexing", N);
3849 else
3850 New_Subp := Relocate_Node (Subp);
3851 Set_Entity (Subp, Nam);
3853 if Component_Type (Ret_Type) /= Any_Type then
3854 Index_Node :=
3855 Make_Indexed_Component (Loc,
3856 Prefix =>
3857 Make_Function_Call (Loc,
3858 Name => New_Subp),
3859 Expressions => Parameter_Associations (N));
3861 -- Since we are correcting a node classification error made
3862 -- by the parser, we call Replace rather than Rewrite.
3864 Replace (N, Index_Node);
3865 Set_Etype (Prefix (N), Ret_Type);
3866 Set_Etype (N, Typ);
3867 Resolve_Indexed_Component (N, Typ);
3868 Check_Elab_Call (Prefix (N));
3869 end if;
3870 end if;
3872 return;
3873 end;
3875 else
3876 Set_Etype (N, Etype (Nam));
3877 end if;
3879 -- In the case where the call is to an overloaded subprogram, Analyze
3880 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
3881 -- such a case Normalize_Actuals needs to be called once more to order
3882 -- the actuals correctly. Otherwise the call will have the ordering
3883 -- given by the last overloaded subprogram whether this is the correct
3884 -- one being called or not.
3886 if Is_Overloaded (Subp) then
3887 Normalize_Actuals (N, Nam, False, Norm_OK);
3888 pragma Assert (Norm_OK);
3889 end if;
3891 -- In any case, call is fully resolved now. Reset Overload flag, to
3892 -- prevent subsequent overload resolution if node is analyzed again
3894 Set_Is_Overloaded (Subp, False);
3895 Set_Is_Overloaded (N, False);
3897 -- If we are calling the current subprogram from immediately within its
3898 -- body, then that is the case where we can sometimes detect cases of
3899 -- infinite recursion statically. Do not try this in case restriction
3900 -- No_Recursion is in effect anyway.
3902 Scop := Current_Scope;
3904 if Nam = Scop
3905 and then not Restriction_Active (No_Recursion)
3906 and then Check_Infinite_Recursion (N)
3907 then
3908 -- Here we detected and flagged an infinite recursion, so we do
3909 -- not need to test the case below for further warnings.
3911 null;
3913 -- If call is to immediately containing subprogram, then check for
3914 -- the case of a possible run-time detectable infinite recursion.
3916 else
3917 while Scop /= Standard_Standard loop
3918 if Nam = Scop then
3919 -- Although in general recursion is not statically checkable,
3920 -- the case of calling an immediately containing subprogram
3921 -- is easy to catch.
3923 Check_Restriction (No_Recursion, N);
3925 -- If the recursive call is to a parameterless procedure, then
3926 -- even if we can't statically detect infinite recursion, this
3927 -- is pretty suspicious, and we output a warning. Furthermore,
3928 -- we will try later to detect some cases here at run time by
3929 -- expanding checking code (see Detect_Infinite_Recursion in
3930 -- package Exp_Ch6).
3932 -- If the recursive call is within a handler we do not emit a
3933 -- warning, because this is a common idiom: loop until input
3934 -- is correct, catch illegal input in handler and restart.
3936 if No (First_Formal (Nam))
3937 and then Etype (Nam) = Standard_Void_Type
3938 and then not Error_Posted (N)
3939 and then Nkind (Parent (N)) /= N_Exception_Handler
3940 then
3941 Set_Has_Recursive_Call (Nam);
3942 Error_Msg_N ("possible infinite recursion?", N);
3944 end if;
3946 exit;
3947 end if;
3949 Scop := Scope (Scop);
3950 end loop;
3951 end if;
3953 -- If subprogram name is a predefined operator, it was given in
3954 -- functional notation. Replace call node with operator node, so
3955 -- that actuals can be resolved appropriately.
3957 if Is_Predefined_Op (Nam) or else Ekind (Nam) = E_Operator then
3958 Make_Call_Into_Operator (N, Typ, Entity (Name (N)));
3959 return;
3961 elsif Present (Alias (Nam))
3962 and then Is_Predefined_Op (Alias (Nam))
3963 then
3964 Resolve_Actuals (N, Nam);
3965 Make_Call_Into_Operator (N, Typ, Alias (Nam));
3966 return;
3967 end if;
3969 -- Create a transient scope if the resulting type requires it
3971 -- There are 3 notable exceptions: in init procs, the transient scope
3972 -- overhead is not needed and even incorrect due to the actual expansion
3973 -- of adjust calls; the second case is enumeration literal pseudo calls,
3974 -- the other case is intrinsic subprograms (Unchecked_Conversion and
3975 -- source information functions) that do not use the secondary stack
3976 -- even though the return type is unconstrained.
3978 -- If this is an initialization call for a type whose initialization
3979 -- uses the secondary stack, we also need to create a transient scope
3980 -- for it, precisely because we will not do it within the init proc
3981 -- itself.
3983 -- If the subprogram is marked Inlined_Always, then even if it returns
3984 -- an unconstrained type the call does not require use of the secondary
3985 -- stack.
3987 if Is_Inlined (Nam)
3988 and then Present (First_Rep_Item (Nam))
3989 and then Nkind (First_Rep_Item (Nam)) = N_Pragma
3990 and then Chars (First_Rep_Item (Nam)) = Name_Inline_Always
3991 then
3992 null;
3994 elsif Expander_Active
3995 and then Is_Type (Etype (Nam))
3996 and then Requires_Transient_Scope (Etype (Nam))
3997 and then Ekind (Nam) /= E_Enumeration_Literal
3998 and then not Within_Init_Proc
3999 and then not Is_Intrinsic_Subprogram (Nam)
4000 then
4001 Establish_Transient_Scope
4002 (N, Sec_Stack => not Functions_Return_By_DSP_On_Target);
4004 -- If the call appears within the bounds of a loop, it will
4005 -- be rewritten and reanalyzed, nothing left to do here.
4007 if Nkind (N) /= N_Function_Call then
4008 return;
4009 end if;
4011 elsif Is_Init_Proc (Nam)
4012 and then not Within_Init_Proc
4013 then
4014 Check_Initialization_Call (N, Nam);
4015 end if;
4017 -- A protected function cannot be called within the definition of the
4018 -- enclosing protected type.
4020 if Is_Protected_Type (Scope (Nam))
4021 and then In_Open_Scopes (Scope (Nam))
4022 and then not Has_Completion (Scope (Nam))
4023 then
4024 Error_Msg_NE
4025 ("& cannot be called before end of protected definition", N, Nam);
4026 end if;
4028 -- Propagate interpretation to actuals, and add default expressions
4029 -- where needed.
4031 if Present (First_Formal (Nam)) then
4032 Resolve_Actuals (N, Nam);
4034 -- Overloaded literals are rewritten as function calls, for
4035 -- purpose of resolution. After resolution, we can replace
4036 -- the call with the literal itself.
4038 elsif Ekind (Nam) = E_Enumeration_Literal then
4039 Copy_Node (Subp, N);
4040 Resolve_Entity_Name (N, Typ);
4042 -- Avoid validation, since it is a static function call
4044 return;
4045 end if;
4047 -- If the subprogram is a primitive operation, check whether or not
4048 -- it is a correct dispatching call.
4050 if Is_Overloadable (Nam)
4051 and then Is_Dispatching_Operation (Nam)
4052 then
4053 Check_Dispatching_Call (N);
4055 elsif Is_Abstract (Nam)
4056 and then not In_Instance
4057 then
4058 Error_Msg_NE ("cannot call abstract subprogram &!", N, Nam);
4059 end if;
4061 if Is_Intrinsic_Subprogram (Nam) then
4062 Check_Intrinsic_Call (N);
4063 end if;
4065 Eval_Call (N);
4066 Check_Elab_Call (N);
4067 end Resolve_Call;
4069 -------------------------------
4070 -- Resolve_Character_Literal --
4071 -------------------------------
4073 procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id) is
4074 B_Typ : constant Entity_Id := Base_Type (Typ);
4075 C : Entity_Id;
4077 begin
4078 -- Verify that the character does belong to the type of the context
4080 Set_Etype (N, B_Typ);
4081 Eval_Character_Literal (N);
4083 -- Wide_Wide_Character literals must always be defined, since the set
4084 -- of wide wide character literals is complete, i.e. if a character
4085 -- literal is accepted by the parser, then it is OK for wide wide
4086 -- character (out of range character literals are rejected).
4088 if Root_Type (B_Typ) = Standard_Wide_Wide_Character then
4089 return;
4091 -- Always accept character literal for type Any_Character, which
4092 -- occurs in error situations and in comparisons of literals, both
4093 -- of which should accept all literals.
4095 elsif B_Typ = Any_Character then
4096 return;
4098 -- For Standard.Character or a type derived from it, check that
4099 -- the literal is in range
4101 elsif Root_Type (B_Typ) = Standard_Character then
4102 if In_Character_Range (UI_To_CC (Char_Literal_Value (N))) then
4103 return;
4104 end if;
4106 -- For Standard.Wide_Character or a type derived from it, check
4107 -- that the literal is in range
4109 elsif Root_Type (B_Typ) = Standard_Wide_Character then
4110 if In_Wide_Character_Range (UI_To_CC (Char_Literal_Value (N))) then
4111 return;
4112 end if;
4114 -- For Standard.Wide_Wide_Character or a type derived from it, we
4115 -- know the literal is in range, since the parser checked!
4117 elsif Root_Type (B_Typ) = Standard_Wide_Wide_Character then
4118 return;
4120 -- If the entity is already set, this has already been resolved in
4121 -- a generic context, or comes from expansion. Nothing else to do.
4123 elsif Present (Entity (N)) then
4124 return;
4126 -- Otherwise we have a user defined character type, and we can use
4127 -- the standard visibility mechanisms to locate the referenced entity
4129 else
4130 C := Current_Entity (N);
4131 while Present (C) loop
4132 if Etype (C) = B_Typ then
4133 Set_Entity_With_Style_Check (N, C);
4134 Generate_Reference (C, N);
4135 return;
4136 end if;
4138 C := Homonym (C);
4139 end loop;
4140 end if;
4142 -- If we fall through, then the literal does not match any of the
4143 -- entries of the enumeration type. This isn't just a constraint
4144 -- error situation, it is an illegality (see RM 4.2).
4146 Error_Msg_NE
4147 ("character not defined for }", N, First_Subtype (B_Typ));
4148 end Resolve_Character_Literal;
4150 ---------------------------
4151 -- Resolve_Comparison_Op --
4152 ---------------------------
4154 -- Context requires a boolean type, and plays no role in resolution.
4155 -- Processing identical to that for equality operators. The result
4156 -- type is the base type, which matters when pathological subtypes of
4157 -- booleans with limited ranges are used.
4159 procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id) is
4160 L : constant Node_Id := Left_Opnd (N);
4161 R : constant Node_Id := Right_Opnd (N);
4162 T : Entity_Id;
4164 begin
4165 -- If this is an intrinsic operation which is not predefined, use
4166 -- the types of its declared arguments to resolve the possibly
4167 -- overloaded operands. Otherwise the operands are unambiguous and
4168 -- specify the expected type.
4170 if Scope (Entity (N)) /= Standard_Standard then
4171 T := Etype (First_Entity (Entity (N)));
4173 else
4174 T := Find_Unique_Type (L, R);
4176 if T = Any_Fixed then
4177 T := Unique_Fixed_Point_Type (L);
4178 end if;
4179 end if;
4181 Set_Etype (N, Base_Type (Typ));
4184 if T /= Any_Type then
4185 if T = Any_String
4186 or else T = Any_Composite
4187 or else T = Any_Character
4188 then
4189 if T = Any_Character then
4190 Ambiguous_Character (L);
4191 else
4192 Error_Msg_N ("ambiguous operands for comparison", N);
4193 end if;
4195 Set_Etype (N, Any_Type);
4196 return;
4198 else
4199 Resolve (L, T);
4200 Resolve (R, T);
4201 Check_Unset_Reference (L);
4202 Check_Unset_Reference (R);
4203 Generate_Operator_Reference (N, T);
4204 Eval_Relational_Op (N);
4205 end if;
4206 end if;
4207 end Resolve_Comparison_Op;
4209 ------------------------------------
4210 -- Resolve_Conditional_Expression --
4211 ------------------------------------
4213 procedure Resolve_Conditional_Expression (N : Node_Id; Typ : Entity_Id) is
4214 Condition : constant Node_Id := First (Expressions (N));
4215 Then_Expr : constant Node_Id := Next (Condition);
4216 Else_Expr : constant Node_Id := Next (Then_Expr);
4218 begin
4219 Resolve (Condition, Standard_Boolean);
4220 Resolve (Then_Expr, Typ);
4221 Resolve (Else_Expr, Typ);
4223 Set_Etype (N, Typ);
4224 Eval_Conditional_Expression (N);
4225 end Resolve_Conditional_Expression;
4227 -----------------------------------------
4228 -- Resolve_Discrete_Subtype_Indication --
4229 -----------------------------------------
4231 procedure Resolve_Discrete_Subtype_Indication
4232 (N : Node_Id;
4233 Typ : Entity_Id)
4234 is
4235 R : Node_Id;
4236 S : Entity_Id;
4238 begin
4239 Analyze (Subtype_Mark (N));
4240 S := Entity (Subtype_Mark (N));
4242 if Nkind (Constraint (N)) /= N_Range_Constraint then
4243 Error_Msg_N ("expect range constraint for discrete type", N);
4244 Set_Etype (N, Any_Type);
4246 else
4247 R := Range_Expression (Constraint (N));
4249 if R = Error then
4250 return;
4251 end if;
4253 Analyze (R);
4255 if Base_Type (S) /= Base_Type (Typ) then
4256 Error_Msg_NE
4257 ("expect subtype of }", N, First_Subtype (Typ));
4259 -- Rewrite the constraint as a range of Typ
4260 -- to allow compilation to proceed further.
4262 Set_Etype (N, Typ);
4263 Rewrite (Low_Bound (R),
4264 Make_Attribute_Reference (Sloc (Low_Bound (R)),
4265 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
4266 Attribute_Name => Name_First));
4267 Rewrite (High_Bound (R),
4268 Make_Attribute_Reference (Sloc (High_Bound (R)),
4269 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
4270 Attribute_Name => Name_First));
4272 else
4273 Resolve (R, Typ);
4274 Set_Etype (N, Etype (R));
4276 -- Additionally, we must check that the bounds are compatible
4277 -- with the given subtype, which might be different from the
4278 -- type of the context.
4280 Apply_Range_Check (R, S);
4282 -- ??? If the above check statically detects a Constraint_Error
4283 -- it replaces the offending bound(s) of the range R with a
4284 -- Constraint_Error node. When the itype which uses these bounds
4285 -- is frozen the resulting call to Duplicate_Subexpr generates
4286 -- a new temporary for the bounds.
4288 -- Unfortunately there are other itypes that are also made depend
4289 -- on these bounds, so when Duplicate_Subexpr is called they get
4290 -- a forward reference to the newly created temporaries and Gigi
4291 -- aborts on such forward references. This is probably sign of a
4292 -- more fundamental problem somewhere else in either the order of
4293 -- itype freezing or the way certain itypes are constructed.
4295 -- To get around this problem we call Remove_Side_Effects right
4296 -- away if either bounds of R are a Constraint_Error.
4298 declare
4299 L : constant Node_Id := Low_Bound (R);
4300 H : constant Node_Id := High_Bound (R);
4302 begin
4303 if Nkind (L) = N_Raise_Constraint_Error then
4304 Remove_Side_Effects (L);
4305 end if;
4307 if Nkind (H) = N_Raise_Constraint_Error then
4308 Remove_Side_Effects (H);
4309 end if;
4310 end;
4312 Check_Unset_Reference (Low_Bound (R));
4313 Check_Unset_Reference (High_Bound (R));
4314 end if;
4315 end if;
4316 end Resolve_Discrete_Subtype_Indication;
4318 -------------------------
4319 -- Resolve_Entity_Name --
4320 -------------------------
4322 -- Used to resolve identifiers and expanded names
4324 procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id) is
4325 E : constant Entity_Id := Entity (N);
4327 begin
4328 -- If garbage from errors, set to Any_Type and return
4330 if No (E) and then Total_Errors_Detected /= 0 then
4331 Set_Etype (N, Any_Type);
4332 return;
4333 end if;
4335 -- Replace named numbers by corresponding literals. Note that this is
4336 -- the one case where Resolve_Entity_Name must reset the Etype, since
4337 -- it is currently marked as universal.
4339 if Ekind (E) = E_Named_Integer then
4340 Set_Etype (N, Typ);
4341 Eval_Named_Integer (N);
4343 elsif Ekind (E) = E_Named_Real then
4344 Set_Etype (N, Typ);
4345 Eval_Named_Real (N);
4347 -- Allow use of subtype only if it is a concurrent type where we are
4348 -- currently inside the body. This will eventually be expanded
4349 -- into a call to Self (for tasks) or _object (for protected
4350 -- objects). Any other use of a subtype is invalid.
4352 elsif Is_Type (E) then
4353 if Is_Concurrent_Type (E)
4354 and then In_Open_Scopes (E)
4355 then
4356 null;
4357 else
4358 Error_Msg_N
4359 ("invalid use of subtype mark in expression or call", N);
4360 end if;
4362 -- Check discriminant use if entity is discriminant in current scope,
4363 -- i.e. discriminant of record or concurrent type currently being
4364 -- analyzed. Uses in corresponding body are unrestricted.
4366 elsif Ekind (E) = E_Discriminant
4367 and then Scope (E) = Current_Scope
4368 and then not Has_Completion (Current_Scope)
4369 then
4370 Check_Discriminant_Use (N);
4372 -- A parameterless generic function cannot appear in a context that
4373 -- requires resolution.
4375 elsif Ekind (E) = E_Generic_Function then
4376 Error_Msg_N ("illegal use of generic function", N);
4378 elsif Ekind (E) = E_Out_Parameter
4379 and then Ada_Version = Ada_83
4380 and then (Nkind (Parent (N)) in N_Op
4381 or else (Nkind (Parent (N)) = N_Assignment_Statement
4382 and then N = Expression (Parent (N)))
4383 or else Nkind (Parent (N)) = N_Explicit_Dereference)
4384 then
4385 Error_Msg_N ("(Ada 83) illegal reading of out parameter", N);
4387 -- In all other cases, just do the possible static evaluation
4389 else
4390 -- A deferred constant that appears in an expression must have
4391 -- a completion, unless it has been removed by in-place expansion
4392 -- of an aggregate.
4394 if Ekind (E) = E_Constant
4395 and then Comes_From_Source (E)
4396 and then No (Constant_Value (E))
4397 and then Is_Frozen (Etype (E))
4398 and then not In_Default_Expression
4399 and then not Is_Imported (E)
4400 then
4402 if No_Initialization (Parent (E))
4403 or else (Present (Full_View (E))
4404 and then No_Initialization (Parent (Full_View (E))))
4405 then
4406 null;
4407 else
4408 Error_Msg_N (
4409 "deferred constant is frozen before completion", N);
4410 end if;
4411 end if;
4413 Eval_Entity_Name (N);
4414 end if;
4415 end Resolve_Entity_Name;
4417 -------------------
4418 -- Resolve_Entry --
4419 -------------------
4421 procedure Resolve_Entry (Entry_Name : Node_Id) is
4422 Loc : constant Source_Ptr := Sloc (Entry_Name);
4423 Nam : Entity_Id;
4424 New_N : Node_Id;
4425 S : Entity_Id;
4426 Tsk : Entity_Id;
4427 E_Name : Node_Id;
4428 Index : Node_Id;
4430 function Actual_Index_Type (E : Entity_Id) return Entity_Id;
4431 -- If the bounds of the entry family being called depend on task
4432 -- discriminants, build a new index subtype where a discriminant is
4433 -- replaced with the value of the discriminant of the target task.
4434 -- The target task is the prefix of the entry name in the call.
4436 -----------------------
4437 -- Actual_Index_Type --
4438 -----------------------
4440 function Actual_Index_Type (E : Entity_Id) return Entity_Id is
4441 Typ : constant Entity_Id := Entry_Index_Type (E);
4442 Tsk : constant Entity_Id := Scope (E);
4443 Lo : constant Node_Id := Type_Low_Bound (Typ);
4444 Hi : constant Node_Id := Type_High_Bound (Typ);
4445 New_T : Entity_Id;
4447 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id;
4448 -- If the bound is given by a discriminant, replace with a reference
4449 -- to the discriminant of the same name in the target task.
4450 -- If the entry name is the target of a requeue statement and the
4451 -- entry is in the current protected object, the bound to be used
4452 -- is the discriminal of the object (see apply_range_checks for
4453 -- details of the transformation).
4455 -----------------------------
4456 -- Actual_Discriminant_Ref --
4457 -----------------------------
4459 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id is
4460 Typ : constant Entity_Id := Etype (Bound);
4461 Ref : Node_Id;
4463 begin
4464 Remove_Side_Effects (Bound);
4466 if not Is_Entity_Name (Bound)
4467 or else Ekind (Entity (Bound)) /= E_Discriminant
4468 then
4469 return Bound;
4471 elsif Is_Protected_Type (Tsk)
4472 and then In_Open_Scopes (Tsk)
4473 and then Nkind (Parent (Entry_Name)) = N_Requeue_Statement
4474 then
4475 return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc);
4477 else
4478 Ref :=
4479 Make_Selected_Component (Loc,
4480 Prefix => New_Copy_Tree (Prefix (Prefix (Entry_Name))),
4481 Selector_Name => New_Occurrence_Of (Entity (Bound), Loc));
4482 Analyze (Ref);
4483 Resolve (Ref, Typ);
4484 return Ref;
4485 end if;
4486 end Actual_Discriminant_Ref;
4488 -- Start of processing for Actual_Index_Type
4490 begin
4491 if not Has_Discriminants (Tsk)
4492 or else (not Is_Entity_Name (Lo)
4493 and then not Is_Entity_Name (Hi))
4494 then
4495 return Entry_Index_Type (E);
4497 else
4498 New_T := Create_Itype (Ekind (Typ), Parent (Entry_Name));
4499 Set_Etype (New_T, Base_Type (Typ));
4500 Set_Size_Info (New_T, Typ);
4501 Set_RM_Size (New_T, RM_Size (Typ));
4502 Set_Scalar_Range (New_T,
4503 Make_Range (Sloc (Entry_Name),
4504 Low_Bound => Actual_Discriminant_Ref (Lo),
4505 High_Bound => Actual_Discriminant_Ref (Hi)));
4507 return New_T;
4508 end if;
4509 end Actual_Index_Type;
4511 -- Start of processing of Resolve_Entry
4513 begin
4514 -- Find name of entry being called, and resolve prefix of name
4515 -- with its own type. The prefix can be overloaded, and the name
4516 -- and signature of the entry must be taken into account.
4518 if Nkind (Entry_Name) = N_Indexed_Component then
4520 -- Case of dealing with entry family within the current tasks
4522 E_Name := Prefix (Entry_Name);
4524 else
4525 E_Name := Entry_Name;
4526 end if;
4528 if Is_Entity_Name (E_Name) then
4529 -- Entry call to an entry (or entry family) in the current task.
4530 -- This is legal even though the task will deadlock. Rewrite as
4531 -- call to current task.
4533 -- This can also be a call to an entry in an enclosing task.
4534 -- If this is a single task, we have to retrieve its name,
4535 -- because the scope of the entry is the task type, not the
4536 -- object. If the enclosing task is a task type, the identity
4537 -- of the task is given by its own self variable.
4539 -- Finally this can be a requeue on an entry of the same task
4540 -- or protected object.
4542 S := Scope (Entity (E_Name));
4544 for J in reverse 0 .. Scope_Stack.Last loop
4546 if Is_Task_Type (Scope_Stack.Table (J).Entity)
4547 and then not Comes_From_Source (S)
4548 then
4549 -- S is an enclosing task or protected object. The concurrent
4550 -- declaration has been converted into a type declaration, and
4551 -- the object itself has an object declaration that follows
4552 -- the type in the same declarative part.
4554 Tsk := Next_Entity (S);
4555 while Etype (Tsk) /= S loop
4556 Next_Entity (Tsk);
4557 end loop;
4559 S := Tsk;
4560 exit;
4562 elsif S = Scope_Stack.Table (J).Entity then
4564 -- Call to current task. Will be transformed into call to Self
4566 exit;
4568 end if;
4569 end loop;
4571 New_N :=
4572 Make_Selected_Component (Loc,
4573 Prefix => New_Occurrence_Of (S, Loc),
4574 Selector_Name =>
4575 New_Occurrence_Of (Entity (E_Name), Loc));
4576 Rewrite (E_Name, New_N);
4577 Analyze (E_Name);
4579 elsif Nkind (Entry_Name) = N_Selected_Component
4580 and then Is_Overloaded (Prefix (Entry_Name))
4581 then
4582 -- Use the entry name (which must be unique at this point) to
4583 -- find the prefix that returns the corresponding task type or
4584 -- protected type.
4586 declare
4587 Pref : constant Node_Id := Prefix (Entry_Name);
4588 Ent : constant Entity_Id := Entity (Selector_Name (Entry_Name));
4589 I : Interp_Index;
4590 It : Interp;
4592 begin
4593 Get_First_Interp (Pref, I, It);
4594 while Present (It.Typ) loop
4595 if Scope (Ent) = It.Typ then
4596 Set_Etype (Pref, It.Typ);
4597 exit;
4598 end if;
4600 Get_Next_Interp (I, It);
4601 end loop;
4602 end;
4603 end if;
4605 if Nkind (Entry_Name) = N_Selected_Component then
4606 Resolve (Prefix (Entry_Name));
4608 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
4609 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
4610 Resolve (Prefix (Prefix (Entry_Name)));
4611 Index := First (Expressions (Entry_Name));
4612 Resolve (Index, Entry_Index_Type (Nam));
4614 -- Up to this point the expression could have been the actual
4615 -- in a simple entry call, and be given by a named association.
4617 if Nkind (Index) = N_Parameter_Association then
4618 Error_Msg_N ("expect expression for entry index", Index);
4619 else
4620 Apply_Range_Check (Index, Actual_Index_Type (Nam));
4621 end if;
4622 end if;
4623 end Resolve_Entry;
4625 ------------------------
4626 -- Resolve_Entry_Call --
4627 ------------------------
4629 procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id) is
4630 Entry_Name : constant Node_Id := Name (N);
4631 Loc : constant Source_Ptr := Sloc (Entry_Name);
4632 Actuals : List_Id;
4633 First_Named : Node_Id;
4634 Nam : Entity_Id;
4635 Norm_OK : Boolean;
4636 Obj : Node_Id;
4637 Was_Over : Boolean;
4639 begin
4640 -- We kill all checks here, because it does not seem worth the
4641 -- effort to do anything better, an entry call is a big operation.
4643 Kill_All_Checks;
4645 -- Processing of the name is similar for entry calls and protected
4646 -- operation calls. Once the entity is determined, we can complete
4647 -- the resolution of the actuals.
4649 -- The selector may be overloaded, in the case of a protected object
4650 -- with overloaded functions. The type of the context is used for
4651 -- resolution.
4653 if Nkind (Entry_Name) = N_Selected_Component
4654 and then Is_Overloaded (Selector_Name (Entry_Name))
4655 and then Typ /= Standard_Void_Type
4656 then
4657 declare
4658 I : Interp_Index;
4659 It : Interp;
4661 begin
4662 Get_First_Interp (Selector_Name (Entry_Name), I, It);
4663 while Present (It.Typ) loop
4664 if Covers (Typ, It.Typ) then
4665 Set_Entity (Selector_Name (Entry_Name), It.Nam);
4666 Set_Etype (Entry_Name, It.Typ);
4669 end if;
4671 Get_Next_Interp (I, It);
4672 end loop;
4673 end;
4674 end if;
4676 Resolve_Entry (Entry_Name);
4678 if Nkind (Entry_Name) = N_Selected_Component then
4680 -- Simple entry call
4682 Nam := Entity (Selector_Name (Entry_Name));
4683 Obj := Prefix (Entry_Name);
4684 Was_Over := Is_Overloaded (Selector_Name (Entry_Name));
4686 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
4688 -- Call to member of entry family
4690 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
4691 Obj := Prefix (Prefix (Entry_Name));
4692 Was_Over := Is_Overloaded (Selector_Name (Prefix (Entry_Name)));
4693 end if;
4695 -- We cannot in general check the maximum depth of protected entry
4696 -- calls at compile time. But we can tell that any protected entry
4697 -- call at all violates a specified nesting depth of zero.
4699 if Is_Protected_Type (Scope (Nam)) then
4700 Check_Restriction (Max_Entry_Queue_Length, N);
4701 end if;
4703 -- Use context type to disambiguate a protected function that can be
4704 -- called without actuals and that returns an array type, and where
4705 -- the argument list may be an indexing of the returned value.
4707 if Ekind (Nam) = E_Function
4708 and then Needs_No_Actuals (Nam)
4709 and then Present (Parameter_Associations (N))
4710 and then
4711 ((Is_Array_Type (Etype (Nam))
4712 and then Covers (Typ, Component_Type (Etype (Nam))))
4714 or else (Is_Access_Type (Etype (Nam))
4715 and then Is_Array_Type (Designated_Type (Etype (Nam)))
4716 and then Covers (Typ,
4717 Component_Type (Designated_Type (Etype (Nam))))))
4718 then
4719 declare
4720 Index_Node : Node_Id;
4722 begin
4723 Index_Node :=
4724 Make_Indexed_Component (Loc,
4725 Prefix =>
4726 Make_Function_Call (Loc,
4727 Name => Relocate_Node (Entry_Name)),
4728 Expressions => Parameter_Associations (N));
4730 -- Since we are correcting a node classification error made by
4731 -- the parser, we call Replace rather than Rewrite.
4733 Replace (N, Index_Node);
4734 Set_Etype (Prefix (N), Etype (Nam));
4735 Set_Etype (N, Typ);
4736 Resolve_Indexed_Component (N, Typ);
4737 return;
4738 end;
4739 end if;
4741 -- The operation name may have been overloaded. Order the actuals
4742 -- according to the formals of the resolved entity, and set the
4743 -- return type to that of the operation.
4745 if Was_Over then
4746 Normalize_Actuals (N, Nam, False, Norm_OK);
4747 pragma Assert (Norm_OK);
4748 Set_Etype (N, Etype (Nam));
4749 end if;
4751 Resolve_Actuals (N, Nam);
4752 Generate_Reference (Nam, Entry_Name);
4754 if Ekind (Nam) = E_Entry
4755 or else Ekind (Nam) = E_Entry_Family
4756 then
4757 Check_Potentially_Blocking_Operation (N);
4758 end if;
4760 -- Verify that a procedure call cannot masquerade as an entry
4761 -- call where an entry call is expected.
4763 if Ekind (Nam) = E_Procedure then
4764 if Nkind (Parent (N)) = N_Entry_Call_Alternative
4765 and then N = Entry_Call_Statement (Parent (N))
4766 then
4767 Error_Msg_N ("entry call required in select statement", N);
4769 elsif Nkind (Parent (N)) = N_Triggering_Alternative
4770 and then N = Triggering_Statement (Parent (N))
4771 then
4772 Error_Msg_N ("triggering statement cannot be procedure call", N);
4774 elsif Ekind (Scope (Nam)) = E_Task_Type
4775 and then not In_Open_Scopes (Scope (Nam))
4776 then
4777 Error_Msg_N ("task has no entry with this name", Entry_Name);
4778 end if;
4779 end if;
4781 -- After resolution, entry calls and protected procedure calls
4782 -- are changed into entry calls, for expansion. The structure
4783 -- of the node does not change, so it can safely be done in place.
4784 -- Protected function calls must keep their structure because they
4785 -- are subexpressions.
4787 if Ekind (Nam) /= E_Function then
4789 -- A protected operation that is not a function may modify the
4790 -- corresponding object, and cannot apply to a constant.
4791 -- If this is an internal call, the prefix is the type itself.
4793 if Is_Protected_Type (Scope (Nam))
4794 and then not Is_Variable (Obj)
4795 and then (not Is_Entity_Name (Obj)
4796 or else not Is_Type (Entity (Obj)))
4797 then
4798 Error_Msg_N
4799 ("prefix of protected procedure or entry call must be variable",
4800 Entry_Name);
4801 end if;
4803 Actuals := Parameter_Associations (N);
4804 First_Named := First_Named_Actual (N);
4806 Rewrite (N,
4807 Make_Entry_Call_Statement (Loc,
4808 Name => Entry_Name,
4809 Parameter_Associations => Actuals));
4811 Set_First_Named_Actual (N, First_Named);
4812 Set_Analyzed (N, True);
4814 -- Protected functions can return on the secondary stack, in which
4815 -- case we must trigger the transient scope mechanism.
4817 elsif Expander_Active
4818 and then Requires_Transient_Scope (Etype (Nam))
4819 then
4820 Establish_Transient_Scope (N,
4821 Sec_Stack => not Functions_Return_By_DSP_On_Target);
4822 end if;
4823 end Resolve_Entry_Call;
4825 -------------------------
4826 -- Resolve_Equality_Op --
4827 -------------------------
4829 -- Both arguments must have the same type, and the boolean context
4830 -- does not participate in the resolution. The first pass verifies
4831 -- that the interpretation is not ambiguous, and the type of the left
4832 -- argument is correctly set, or is Any_Type in case of ambiguity.
4833 -- If both arguments are strings or aggregates, allocators, or Null,
4834 -- they are ambiguous even though they carry a single (universal) type.
4835 -- Diagnose this case here.
4837 procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id) is
4838 L : constant Node_Id := Left_Opnd (N);
4839 R : constant Node_Id := Right_Opnd (N);
4840 T : Entity_Id := Find_Unique_Type (L, R);
4842 function Find_Unique_Access_Type return Entity_Id;
4843 -- In the case of allocators, make a last-ditch attempt to find a single
4844 -- access type with the right designated type. This is semantically
4845 -- dubious, and of no interest to any real code, but c48008a makes it
4846 -- all worthwhile.
4848 -----------------------------
4849 -- Find_Unique_Access_Type --
4850 -----------------------------
4852 function Find_Unique_Access_Type return Entity_Id is
4853 Acc : Entity_Id;
4854 E : Entity_Id;
4855 S : Entity_Id;
4857 begin
4858 if Ekind (Etype (R)) = E_Allocator_Type then
4859 Acc := Designated_Type (Etype (R));
4861 elsif Ekind (Etype (L)) = E_Allocator_Type then
4862 Acc := Designated_Type (Etype (L));
4864 else
4865 return Empty;
4866 end if;
4868 S := Current_Scope;
4869 while S /= Standard_Standard loop
4870 E := First_Entity (S);
4871 while Present (E) loop
4872 if Is_Type (E)
4873 and then Is_Access_Type (E)
4874 and then Ekind (E) /= E_Allocator_Type
4875 and then Designated_Type (E) = Base_Type (Acc)
4876 then
4877 return E;
4878 end if;
4880 Next_Entity (E);
4881 end loop;
4883 S := Scope (S);
4884 end loop;
4886 return Empty;
4887 end Find_Unique_Access_Type;
4889 -- Start of processing for Resolve_Equality_Op
4891 begin
4892 Set_Etype (N, Base_Type (Typ));
4895 if T = Any_Fixed then
4896 T := Unique_Fixed_Point_Type (L);
4897 end if;
4899 if T /= Any_Type then
4900 if T = Any_String
4901 or else T = Any_Composite
4902 or else T = Any_Character
4903 then
4904 if T = Any_Character then
4905 Ambiguous_Character (L);
4906 else
4907 Error_Msg_N ("ambiguous operands for equality", N);
4908 end if;
4910 Set_Etype (N, Any_Type);
4911 return;
4913 elsif T = Any_Access
4914 or else Ekind (T) = E_Allocator_Type
4915 then
4916 T := Find_Unique_Access_Type;
4918 if No (T) then
4919 Error_Msg_N ("ambiguous operands for equality", N);
4920 Set_Etype (N, Any_Type);
4921 return;
4922 end if;
4923 end if;
4925 Resolve (L, T);
4926 Resolve (R, T);
4928 if Warn_On_Redundant_Constructs
4929 and then Comes_From_Source (N)
4930 and then Is_Entity_Name (R)
4931 and then Entity (R) = Standard_True
4932 and then Comes_From_Source (R)
4933 then
4934 Error_Msg_N ("comparison with True is redundant?", R);
4935 end if;
4937 Check_Unset_Reference (L);
4938 Check_Unset_Reference (R);
4939 Generate_Operator_Reference (N, T);
4941 -- If this is an inequality, it may be the implicit inequality
4942 -- created for a user-defined operation, in which case the corres-
4943 -- ponding equality operation is not intrinsic, and the operation
4944 -- cannot be constant-folded. Else fold.
4946 if Nkind (N) = N_Op_Eq
4947 or else Comes_From_Source (Entity (N))
4948 or else Ekind (Entity (N)) = E_Operator
4949 or else Is_Intrinsic_Subprogram
4950 (Corresponding_Equality (Entity (N)))
4951 then
4952 Eval_Relational_Op (N);
4953 elsif Nkind (N) = N_Op_Ne
4954 and then Is_Abstract (Entity (N))
4955 then
4956 Error_Msg_NE ("cannot call abstract subprogram &!", N, Entity (N));
4957 end if;
4959 -- Ada 2005: If one operand is an anonymous access type, convert
4960 -- the other operand to it, to ensure that the underlying types
4961 -- match in the back-end.
4962 -- We apply the same conversion in the case one of the operands is
4963 -- a private subtype of the type of the other.
4965 if Ekind (T) = E_Anonymous_Access_Type
4966 or else Is_Private_Type (T)
4967 then
4968 if Etype (L) /= T then
4969 Rewrite (L,
4970 Make_Unchecked_Type_Conversion (Sloc (L),
4971 Subtype_Mark => New_Occurrence_Of (T, Sloc (L)),
4972 Expression => Relocate_Node (L)));
4973 Analyze_And_Resolve (L, T);
4974 end if;
4976 if (Etype (R)) /= T then
4977 Rewrite (R,
4978 Make_Unchecked_Type_Conversion (Sloc (R),
4979 Subtype_Mark => New_Occurrence_Of (Etype (L), Sloc (R)),
4980 Expression => Relocate_Node (R)));
4981 Analyze_And_Resolve (R, T);
4982 end if;
4983 end if;
4984 end if;
4985 end Resolve_Equality_Op;
4987 ----------------------------------
4988 -- Resolve_Explicit_Dereference --
4989 ----------------------------------
4991 procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id) is
4992 Loc : constant Source_Ptr := Sloc (N);
4993 New_N : Node_Id;
4994 P : constant Node_Id := Prefix (N);
4995 I : Interp_Index;
4996 It : Interp;
4998 begin
4999 Check_Fully_Declared_Prefix (Typ, P);
5001 if Is_Overloaded (P) then
5003 -- Use the context type to select the prefix that has the correct
5004 -- designated type.
5006 Get_First_Interp (P, I, It);
5007 while Present (It.Typ) loop
5008 exit when Is_Access_Type (It.Typ)
5009 and then Covers (Typ, Designated_Type (It.Typ));
5010 Get_Next_Interp (I, It);
5011 end loop;
5013 if Present (It.Typ) then
5014 Resolve (P, It.Typ);
5015 else
5016 -- If no interpretation covers the designated type of the prefix,
5017 -- this is the pathological case where not all implementations of
5018 -- the prefix allow the interpretation of the node as a call. Now
5019 -- that the expected type is known, Remove other interpretations
5020 -- from prefix, rewrite it as a call, and resolve again, so that
5021 -- the proper call node is generated.
5023 Get_First_Interp (P, I, It);
5024 while Present (It.Typ) loop
5025 if Ekind (It.Typ) /= E_Access_Subprogram_Type then
5026 Remove_Interp (I);
5027 end if;
5029 Get_Next_Interp (I, It);
5030 end loop;
5032 New_N :=
5033 Make_Function_Call (Loc,
5034 Name =>
5035 Make_Explicit_Dereference (Loc,
5036 Prefix => P),
5037 Parameter_Associations => New_List);
5039 Save_Interps (N, New_N);
5040 Rewrite (N, New_N);
5041 Analyze_And_Resolve (N, Typ);
5042 return;
5043 end if;
5045 Set_Etype (N, Designated_Type (It.Typ));
5047 else
5048 Resolve (P);
5049 end if;
5051 if Is_Access_Type (Etype (P)) then
5052 Apply_Access_Check (N);
5053 end if;
5055 -- If the designated type is a packed unconstrained array type, and the
5056 -- explicit dereference is not in the context of an attribute reference,
5057 -- then we must compute and set the actual subtype, since it is needed
5058 -- by Gigi. The reason we exclude the attribute case is that this is
5059 -- handled fine by Gigi, and in fact we use such attributes to build the
5060 -- actual subtype. We also exclude generated code (which builds actual
5061 -- subtypes directly if they are needed).
5063 if Is_Array_Type (Etype (N))
5064 and then Is_Packed (Etype (N))
5065 and then not Is_Constrained (Etype (N))
5066 and then Nkind (Parent (N)) /= N_Attribute_Reference
5067 and then Comes_From_Source (N)
5068 then
5069 Set_Etype (N, Get_Actual_Subtype (N));
5070 end if;
5072 -- Note: there is no Eval processing required for an explicit deference,
5073 -- because the type is known to be an allocators, and allocator
5074 -- expressions can never be static.
5076 end Resolve_Explicit_Dereference;
5078 -------------------------------
5079 -- Resolve_Indexed_Component --
5080 -------------------------------
5082 procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id) is
5083 Name : constant Node_Id := Prefix (N);
5084 Expr : Node_Id;
5085 Array_Type : Entity_Id := Empty; -- to prevent junk warning
5086 Index : Node_Id;
5088 begin
5089 if Is_Overloaded (Name) then
5091 -- Use the context type to select the prefix that yields the correct
5092 -- component type.
5094 declare
5095 I : Interp_Index;
5096 It : Interp;
5097 I1 : Interp_Index := 0;
5098 P : constant Node_Id := Prefix (N);
5099 Found : Boolean := False;
5101 begin
5102 Get_First_Interp (P, I, It);
5103 while Present (It.Typ) loop
5104 if (Is_Array_Type (It.Typ)
5105 and then Covers (Typ, Component_Type (It.Typ)))
5106 or else (Is_Access_Type (It.Typ)
5107 and then Is_Array_Type (Designated_Type (It.Typ))
5108 and then Covers
5109 (Typ, Component_Type (Designated_Type (It.Typ))))
5110 then
5111 if Found then
5112 It := Disambiguate (P, I1, I, Any_Type);
5114 if It = No_Interp then
5115 Error_Msg_N ("ambiguous prefix for indexing", N);
5116 Set_Etype (N, Typ);
5117 return;
5119 else
5120 Found := True;
5121 Array_Type := It.Typ;
5122 I1 := I;
5123 end if;
5125 else
5126 Found := True;
5127 Array_Type := It.Typ;
5128 I1 := I;
5129 end if;
5130 end if;
5132 Get_Next_Interp (I, It);
5133 end loop;
5134 end;
5136 else
5137 Array_Type := Etype (Name);
5138 end if;
5140 Resolve (Name, Array_Type);
5141 Array_Type := Get_Actual_Subtype_If_Available (Name);
5143 -- If prefix is access type, dereference to get real array type.
5144 -- Note: we do not apply an access check because the expander always
5145 -- introduces an explicit dereference, and the check will happen there.
5147 if Is_Access_Type (Array_Type) then
5148 Array_Type := Designated_Type (Array_Type);
5149 end if;
5151 -- If name was overloaded, set component type correctly now
5153 Set_Etype (N, Component_Type (Array_Type));
5155 Index := First_Index (Array_Type);
5156 Expr := First (Expressions (N));
5158 -- The prefix may have resolved to a string literal, in which case its
5159 -- etype has a special representation. This is only possible currently
5160 -- if the prefix is a static concatenation, written in functional
5161 -- notation.
5163 if Ekind (Array_Type) = E_String_Literal_Subtype then
5164 Resolve (Expr, Standard_Positive);
5166 else
5167 while Present (Index) and Present (Expr) loop
5168 Resolve (Expr, Etype (Index));
5169 Check_Unset_Reference (Expr);
5171 if Is_Scalar_Type (Etype (Expr)) then
5172 Apply_Scalar_Range_Check (Expr, Etype (Index));
5173 else
5174 Apply_Range_Check (Expr, Get_Actual_Subtype (Index));
5175 end if;
5177 Next_Index (Index);
5178 Next (Expr);
5179 end loop;
5180 end if;
5182 Eval_Indexed_Component (N);
5183 end Resolve_Indexed_Component;
5185 -----------------------------
5186 -- Resolve_Integer_Literal --
5187 -----------------------------
5189 procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id) is
5190 begin
5191 Set_Etype (N, Typ);
5192 Eval_Integer_Literal (N);
5193 end Resolve_Integer_Literal;
5195 --------------------------------
5196 -- Resolve_Intrinsic_Operator --
5197 --------------------------------
5199 procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id) is
5200 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
5201 Op : Entity_Id;
5202 Arg1 : Node_Id;
5203 Arg2 : Node_Id;
5205 begin
5206 Op := Entity (N);
5207 while Scope (Op) /= Standard_Standard loop
5208 Op := Homonym (Op);
5209 pragma Assert (Present (Op));
5210 end loop;
5212 Set_Entity (N, Op);
5213 Set_Is_Overloaded (N, False);
5215 -- If the operand type is private, rewrite with suitable conversions on
5216 -- the operands and the result, to expose the proper underlying numeric
5217 -- type.
5219 if Is_Private_Type (Typ) then
5220 Arg1 := Unchecked_Convert_To (Btyp, Left_Opnd (N));
5222 if Nkind (N) = N_Op_Expon then
5223 Arg2 := Unchecked_Convert_To (Standard_Integer, Right_Opnd (N));
5224 else
5225 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
5226 end if;
5228 Save_Interps (Left_Opnd (N), Expression (Arg1));
5229 Save_Interps (Right_Opnd (N), Expression (Arg2));
5231 Set_Left_Opnd (N, Arg1);
5232 Set_Right_Opnd (N, Arg2);
5234 Set_Etype (N, Btyp);
5235 Rewrite (N, Unchecked_Convert_To (Typ, N));
5236 Resolve (N, Typ);
5238 elsif Typ /= Etype (Left_Opnd (N))
5239 or else Typ /= Etype (Right_Opnd (N))
5240 then
5241 -- Add explicit conversion where needed, and save interpretations
5242 -- in case operands are overloaded.
5244 Arg1 := Convert_To (Typ, Left_Opnd (N));
5245 Arg2 := Convert_To (Typ, Right_Opnd (N));
5247 if Nkind (Arg1) = N_Type_Conversion then
5248 Save_Interps (Left_Opnd (N), Expression (Arg1));
5249 else
5250 Save_Interps (Left_Opnd (N), Arg1);
5251 end if;
5253 if Nkind (Arg2) = N_Type_Conversion then
5254 Save_Interps (Right_Opnd (N), Expression (Arg2));
5255 else
5256 Save_Interps (Right_Opnd (N), Arg2);
5257 end if;
5259 Rewrite (Left_Opnd (N), Arg1);
5260 Rewrite (Right_Opnd (N), Arg2);
5261 Analyze (Arg1);
5262 Analyze (Arg2);
5263 Resolve_Arithmetic_Op (N, Typ);
5265 else
5266 Resolve_Arithmetic_Op (N, Typ);
5267 end if;
5268 end Resolve_Intrinsic_Operator;
5270 --------------------------------------
5271 -- Resolve_Intrinsic_Unary_Operator --
5272 --------------------------------------
5274 procedure Resolve_Intrinsic_Unary_Operator
5275 (N : Node_Id;
5276 Typ : Entity_Id)
5277 is
5278 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
5279 Op : Entity_Id;
5280 Arg2 : Node_Id;
5282 begin
5283 Op := Entity (N);
5284 while Scope (Op) /= Standard_Standard loop
5285 Op := Homonym (Op);
5286 pragma Assert (Present (Op));
5287 end loop;
5289 Set_Entity (N, Op);
5291 if Is_Private_Type (Typ) then
5292 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
5293 Save_Interps (Right_Opnd (N), Expression (Arg2));
5295 Set_Right_Opnd (N, Arg2);
5297 Set_Etype (N, Btyp);
5298 Rewrite (N, Unchecked_Convert_To (Typ, N));
5299 Resolve (N, Typ);
5301 else
5302 Resolve_Unary_Op (N, Typ);
5303 end if;
5304 end Resolve_Intrinsic_Unary_Operator;
5306 ------------------------
5307 -- Resolve_Logical_Op --
5308 ------------------------
5310 procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id) is
5311 B_Typ : Entity_Id;
5312 N_Opr : constant Node_Kind := Nkind (N);
5314 begin
5315 -- Predefined operations on scalar types yield the base type. On the
5316 -- other hand, logical operations on arrays yield the type of the
5317 -- arguments (and the context).
5319 if Is_Array_Type (Typ) then
5320 B_Typ := Typ;
5321 else
5322 B_Typ := Base_Type (Typ);
5323 end if;
5325 -- The following test is required because the operands of the operation
5326 -- may be literals, in which case the resulting type appears to be
5327 -- compatible with a signed integer type, when in fact it is compatible
5328 -- only with modular types. If the context itself is universal, the
5329 -- operation is illegal.
5331 if not Valid_Boolean_Arg (Typ) then
5332 Error_Msg_N ("invalid context for logical operation", N);
5333 Set_Etype (N, Any_Type);
5334 return;
5336 elsif Typ = Any_Modular then
5337 Error_Msg_N
5338 ("no modular type available in this context", N);
5339 Set_Etype (N, Any_Type);
5340 return;
5341 elsif Is_Modular_Integer_Type (Typ)
5342 and then Etype (Left_Opnd (N)) = Universal_Integer
5343 and then Etype (Right_Opnd (N)) = Universal_Integer
5344 then
5345 Check_For_Visible_Operator (N, B_Typ);
5346 end if;
5348 Resolve (Left_Opnd (N), B_Typ);
5349 Resolve (Right_Opnd (N), B_Typ);
5351 Check_Unset_Reference (Left_Opnd (N));
5352 Check_Unset_Reference (Right_Opnd (N));
5354 Set_Etype (N, B_Typ);
5355 Generate_Operator_Reference (N, B_Typ);
5356 Eval_Logical_Op (N);
5358 -- Check for violation of restriction No_Direct_Boolean_Operators
5359 -- if the operator was not eliminated by the Eval_Logical_Op call.
5361 if Nkind (N) = N_Opr
5362 and then Root_Type (Etype (Left_Opnd (N))) = Standard_Boolean
5363 then
5364 Check_Restriction (No_Direct_Boolean_Operators, N);
5365 end if;
5366 end Resolve_Logical_Op;
5368 ---------------------------
5369 -- Resolve_Membership_Op --
5370 ---------------------------
5372 -- The context can only be a boolean type, and does not determine
5373 -- the arguments. Arguments should be unambiguous, but the preference
5374 -- rule for universal types applies.
5376 procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id) is
5377 pragma Warnings (Off, Typ);
5379 L : constant Node_Id := Left_Opnd (N);
5380 R : constant Node_Id := Right_Opnd (N);
5381 T : Entity_Id;
5383 begin
5384 if L = Error or else R = Error then
5385 return;
5386 end if;
5388 if not Is_Overloaded (R)
5389 and then
5390 (Etype (R) = Universal_Integer or else
5391 Etype (R) = Universal_Real)
5392 and then Is_Overloaded (L)
5393 then
5394 T := Etype (R);
5396 -- Ada 2005 (AI-251): Give support to the following case:
5398 -- type I is interface;
5399 -- type T is tagged ...
5401 -- function Test (O : I'Class) is
5402 -- begin
5403 -- return O in T'Class.
5404 -- end Test;
5406 -- In this case we have nothing else to do; the membership test will be
5407 -- done at run-time.
5409 elsif Ada_Version >= Ada_05
5410 and then Is_Class_Wide_Type (Etype (L))
5411 and then Is_Interface (Etype (L))
5412 and then Is_Class_Wide_Type (Etype (R))
5413 and then not Is_Interface (Etype (R))
5414 then
5415 return;
5417 else
5418 T := Intersect_Types (L, R);
5419 end if;
5421 Resolve (L, T);
5422 Check_Unset_Reference (L);
5424 if Nkind (R) = N_Range
5425 and then not Is_Scalar_Type (T)
5426 then
5427 Error_Msg_N ("scalar type required for range", R);
5428 end if;
5430 if Is_Entity_Name (R) then
5431 Freeze_Expression (R);
5432 else
5433 Resolve (R, T);
5434 Check_Unset_Reference (R);
5435 end if;
5437 Eval_Membership_Op (N);
5438 end Resolve_Membership_Op;
5440 ------------------
5441 -- Resolve_Null --
5442 ------------------
5444 procedure Resolve_Null (N : Node_Id; Typ : Entity_Id) is
5445 begin
5446 -- Handle restriction against anonymous null access values This
5447 -- restriction can be turned off using -gnatdh.
5449 -- Ada 2005 (AI-231): Remove restriction
5451 if Ada_Version < Ada_05
5452 and then not Debug_Flag_J
5453 and then Ekind (Typ) = E_Anonymous_Access_Type
5454 and then Comes_From_Source (N)
5455 then
5456 -- In the common case of a call which uses an explicitly null
5457 -- value for an access parameter, give specialized error msg
5459 if Nkind (Parent (N)) = N_Procedure_Call_Statement
5460 or else
5461 Nkind (Parent (N)) = N_Function_Call
5462 then
5463 Error_Msg_N
5464 ("null is not allowed as argument for an access parameter", N);
5466 -- Standard message for all other cases (are there any?)
5468 else
5469 Error_Msg_N
5470 ("null cannot be of an anonymous access type", N);
5471 end if;
5472 end if;
5474 -- In a distributed context, null for a remote access to subprogram
5475 -- may need to be replaced with a special record aggregate. In this
5476 -- case, return after having done the transformation.
5478 if (Ekind (Typ) = E_Record_Type
5479 or else Is_Remote_Access_To_Subprogram_Type (Typ))
5480 and then Remote_AST_Null_Value (N, Typ)
5481 then
5482 return;
5483 end if;
5485 -- The null literal takes its type from the context
5487 Set_Etype (N, Typ);
5488 end Resolve_Null;
5490 -----------------------
5491 -- Resolve_Op_Concat --
5492 -----------------------
5494 procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id) is
5495 Btyp : constant Entity_Id := Base_Type (Typ);
5496 Op1 : constant Node_Id := Left_Opnd (N);
5497 Op2 : constant Node_Id := Right_Opnd (N);
5499 procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean);
5500 -- Internal procedure to resolve one operand of concatenation operator.
5501 -- The operand is either of the array type or of the component type.
5502 -- If the operand is an aggregate, and the component type is composite,
5503 -- this is ambiguous if component type has aggregates.
5505 -------------------------------
5506 -- Resolve_Concatenation_Arg --
5507 -------------------------------
5509 procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean) is
5510 begin
5511 if In_Instance then
5512 if Is_Comp
5513 or else (not Is_Overloaded (Arg)
5514 and then Etype (Arg) /= Any_Composite
5515 and then Covers (Component_Type (Typ), Etype (Arg)))
5516 then
5517 Resolve (Arg, Component_Type (Typ));
5518 else
5519 Resolve (Arg, Btyp);
5520 end if;
5522 elsif Has_Compatible_Type (Arg, Component_Type (Typ)) then
5524 if Nkind (Arg) = N_Aggregate
5525 and then Is_Composite_Type (Component_Type (Typ))
5526 then
5527 if Is_Private_Type (Component_Type (Typ)) then
5528 Resolve (Arg, Btyp);
5530 else
5531 Error_Msg_N ("ambiguous aggregate must be qualified", Arg);
5532 Set_Etype (Arg, Any_Type);
5533 end if;
5535 else
5536 if Is_Overloaded (Arg)
5537 and then Has_Compatible_Type (Arg, Typ)
5538 and then Etype (Arg) /= Any_Type
5539 then
5541 declare
5542 I : Interp_Index;
5543 It : Interp;
5544 Func : Entity_Id;
5546 begin
5547 Get_First_Interp (Arg, I, It);
5548 Func := It.Nam;
5549 Get_Next_Interp (I, It);
5551 -- Special-case the error message when the overloading
5552 -- is caused by a function that yields and array and
5553 -- can be called without parameters.
5555 if It.Nam = Func then
5556 Error_Msg_Sloc := Sloc (Func);
5558 Error_Msg_NE
5560 Error_Msg_NE
5562 Arg, Component_Type (Typ));
5564 else
5565 Error_Msg_N ("ambiguous operand for concatenation!",
5566 Arg);
5567 Get_First_Interp (Arg, I, It);
5568 while Present (It.Nam) loop
5569 Error_Msg_Sloc := Sloc (It.Nam);
5571 if Base_Type (It.Typ) = Base_Type (Typ)
5572 or else Base_Type (It.Typ) =
5573 Base_Type (Component_Type (Typ))
5574 then
5576 end if;
5578 Get_Next_Interp (I, It);
5579 end loop;
5580 end if;
5581 end;
5582 end if;
5584 Resolve (Arg, Component_Type (Typ));
5586 if Nkind (Arg) = N_String_Literal then
5587 Set_Etype (Arg, Component_Type (Typ));
5588 end if;
5590 if Arg = Left_Opnd (N) then
5591 Set_Is_Component_Left_Opnd (N);
5592 else
5593 Set_Is_Component_Right_Opnd (N);
5594 end if;
5595 end if;
5597 else
5598 Resolve (Arg, Btyp);
5599 end if;
5601 Check_Unset_Reference (Arg);
5602 end Resolve_Concatenation_Arg;
5604 -- Start of processing for Resolve_Op_Concat
5606 begin
5607 Set_Etype (N, Btyp);
5609 if Is_Limited_Composite (Btyp) then
5610 Error_Msg_N ("concatenation not available for limited array", N);
5611 Explain_Limited_Type (Btyp, N);
5612 end if;
5614 -- If the operands are themselves concatenations, resolve them as such
5615 -- directly. This removes several layers of recursion and allows GNAT to
5616 -- handle larger multiple concatenations.
5618 if Nkind (Op1) = N_Op_Concat
5619 and then not Is_Array_Type (Component_Type (Typ))
5620 and then Entity (Op1) = Entity (N)
5621 then
5622 Resolve_Op_Concat (Op1, Typ);
5623 else
5624 Resolve_Concatenation_Arg
5625 (Op1, Is_Component_Left_Opnd (N));
5626 end if;
5628 if Nkind (Op2) = N_Op_Concat
5629 and then not Is_Array_Type (Component_Type (Typ))
5630 and then Entity (Op2) = Entity (N)
5631 then
5632 Resolve_Op_Concat (Op2, Typ);
5633 else
5634 Resolve_Concatenation_Arg
5635 (Op2, Is_Component_Right_Opnd (N));
5636 end if;
5638 Generate_Operator_Reference (N, Typ);
5640 if Is_String_Type (Typ) then
5641 Eval_Concatenation (N);
5642 end if;
5644 -- If this is not a static concatenation, but the result is a
5645 -- string type (and not an array of strings) insure that static
5646 -- string operands have their subtypes properly constructed.
5648 if Nkind (N) /= N_String_Literal
5649 and then Is_Character_Type (Component_Type (Typ))
5650 then
5651 Set_String_Literal_Subtype (Op1, Typ);
5652 Set_String_Literal_Subtype (Op2, Typ);
5653 end if;
5654 end Resolve_Op_Concat;
5656 ----------------------
5657 -- Resolve_Op_Expon --
5658 ----------------------
5660 procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id) is
5661 B_Typ : constant Entity_Id := Base_Type (Typ);
5663 begin
5664 -- Catch attempts to do fixed-point exponentation with universal
5665 -- operands, which is a case where the illegality is not caught during
5666 -- normal operator analysis.
5668 if Is_Fixed_Point_Type (Typ) and then Comes_From_Source (N) then
5669 Error_Msg_N ("exponentiation not available for fixed point", N);
5670 return;
5671 end if;
5673 if Comes_From_Source (N)
5674 and then Ekind (Entity (N)) = E_Function
5675 and then Is_Imported (Entity (N))
5676 and then Is_Intrinsic_Subprogram (Entity (N))
5677 then
5678 Resolve_Intrinsic_Operator (N, Typ);
5679 return;
5680 end if;
5682 if Etype (Left_Opnd (N)) = Universal_Integer
5683 or else Etype (Left_Opnd (N)) = Universal_Real
5684 then
5685 Check_For_Visible_Operator (N, B_Typ);
5686 end if;
5688 -- We do the resolution using the base type, because intermediate values
5689 -- in expressions always are of the base type, not a subtype of it.
5691 Resolve (Left_Opnd (N), B_Typ);
5692 Resolve (Right_Opnd (N), Standard_Integer);
5694 Check_Unset_Reference (Left_Opnd (N));
5695 Check_Unset_Reference (Right_Opnd (N));
5697 Set_Etype (N, B_Typ);
5698 Generate_Operator_Reference (N, B_Typ);
5699 Eval_Op_Expon (N);
5701 -- Set overflow checking bit. Much cleverer code needed here eventually
5702 -- and perhaps the Resolve routines should be separated for the various
5703 -- arithmetic operations, since they will need different processing. ???
5705 if Nkind (N) in N_Op then
5706 if not Overflow_Checks_Suppressed (Etype (N)) then
5707 Enable_Overflow_Check (N);
5708 end if;
5709 end if;
5710 end Resolve_Op_Expon;
5712 --------------------
5713 -- Resolve_Op_Not --
5714 --------------------
5716 procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id) is
5717 B_Typ : Entity_Id;
5719 function Parent_Is_Boolean return Boolean;
5720 -- This function determines if the parent node is a boolean operator
5721 -- or operation (comparison op, membership test, or short circuit form)
5722 -- and the not in question is the left operand of this operation.
5723 -- Note that if the not is in parens, then false is returned.
5725 function Parent_Is_Boolean return Boolean is
5726 begin
5727 if Paren_Count (N) /= 0 then
5728 return False;
5730 else
5731 case Nkind (Parent (N)) is
5732 when N_Op_And |
5733 N_Op_Eq |
5734 N_Op_Ge |
5735 N_Op_Gt |
5736 N_Op_Le |
5737 N_Op_Lt |
5738 N_Op_Ne |
5739 N_Op_Or |
5740 N_Op_Xor |
5741 N_In |
5742 N_Not_In |
5743 N_And_Then |
5744 N_Or_Else =>
5746 return Left_Opnd (Parent (N)) = N;
5748 when others =>
5749 return False;
5750 end case;
5751 end if;
5752 end Parent_Is_Boolean;
5754 -- Start of processing for Resolve_Op_Not
5756 begin
5757 -- Predefined operations on scalar types yield the base type. On the
5758 -- other hand, logical operations on arrays yield the type of the
5759 -- arguments (and the context).
5761 if Is_Array_Type (Typ) then
5762 B_Typ := Typ;
5763 else
5764 B_Typ := Base_Type (Typ);
5765 end if;
5767 if not Valid_Boolean_Arg (Typ) then
5768 Error_Msg_N ("invalid operand type for operator&", N);
5769 Set_Etype (N, Any_Type);
5770 return;
5772 elsif Typ = Universal_Integer or else Typ = Any_Modular then
5773 if Parent_Is_Boolean then
5774 Error_Msg_N
5775 ("operand of not must be enclosed in parentheses",
5776 Right_Opnd (N));
5777 else
5778 Error_Msg_N
5779 ("no modular type available in this context", N);
5780 end if;
5782 Set_Etype (N, Any_Type);
5783 return;
5785 else
5786 if not Is_Boolean_Type (Typ)
5787 and then Parent_Is_Boolean
5788 then
5789 Error_Msg_N ("?not expression should be parenthesized here", N);
5790 end if;
5792 Resolve (Right_Opnd (N), B_Typ);
5793 Check_Unset_Reference (Right_Opnd (N));
5794 Set_Etype (N, B_Typ);
5795 Generate_Operator_Reference (N, B_Typ);
5796 Eval_Op_Not (N);
5797 end if;
5798 end Resolve_Op_Not;
5800 -----------------------------
5801 -- Resolve_Operator_Symbol --
5802 -----------------------------
5804 -- Nothing to be done, all resolved already
5806 procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id) is
5807 pragma Warnings (Off, N);
5808 pragma Warnings (Off, Typ);
5810 begin
5811 null;
5812 end Resolve_Operator_Symbol;
5814 ----------------------------------
5815 -- Resolve_Qualified_Expression --
5816 ----------------------------------
5818 procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id) is
5819 pragma Warnings (Off, Typ);
5821 Target_Typ : constant Entity_Id := Entity (Subtype_Mark (N));
5822 Expr : constant Node_Id := Expression (N);
5824 begin
5825 Resolve (Expr, Target_Typ);
5827 -- A qualified expression requires an exact match of the type,
5828 -- class-wide matching is not allowed. However, if the qualifying
5829 -- type is specific and the expression has a class-wide type, it
5830 -- may still be okay, since it can be the result of the expansion
5831 -- of a call to a dispatching function, so we also have to check
5832 -- class-wideness of the type of the expression's original node.
5834 if (Is_Class_Wide_Type (Target_Typ)
5835 or else
5836 (Is_Class_Wide_Type (Etype (Expr))
5837 and then Is_Class_Wide_Type (Etype (Original_Node (Expr)))))
5838 and then Base_Type (Etype (Expr)) /= Base_Type (Target_Typ)
5839 then
5840 Wrong_Type (Expr, Target_Typ);
5841 end if;
5843 -- If the target type is unconstrained, then we reset the type of
5844 -- the result from the type of the expression. For other cases, the
5845 -- actual subtype of the expression is the target type.
5847 if Is_Composite_Type (Target_Typ)
5848 and then not Is_Constrained (Target_Typ)
5849 then
5850 Set_Etype (N, Etype (Expr));
5851 end if;
5853 Eval_Qualified_Expression (N);
5854 end Resolve_Qualified_Expression;
5856 -------------------
5857 -- Resolve_Range --
5858 -------------------
5860 procedure Resolve_Range (N : Node_Id; Typ : Entity_Id) is
5861 L : constant Node_Id := Low_Bound (N);
5862 H : constant Node_Id := High_Bound (N);
5864 begin
5865 Set_Etype (N, Typ);
5866 Resolve (L, Typ);
5867 Resolve (H, Typ);
5869 Check_Unset_Reference (L);
5870 Check_Unset_Reference (H);
5872 -- We have to check the bounds for being within the base range as
5873 -- required for a non-static context. Normally this is automatic and
5874 -- done as part of evaluating expressions, but the N_Range node is an
5875 -- exception, since in GNAT we consider this node to be a subexpression,
5876 -- even though in Ada it is not. The circuit in Sem_Eval could check for
5877 -- this, but that would put the test on the main evaluation path for
5878 -- expressions.
5880 Check_Non_Static_Context (L);
5881 Check_Non_Static_Context (H);
5883 -- If bounds are static, constant-fold them, so size computations
5884 -- are identical between front-end and back-end. Do not perform this
5885 -- transformation while analyzing generic units, as type information
5886 -- would then be lost when reanalyzing the constant node in the
5887 -- instance.
5889 if Is_Discrete_Type (Typ) and then Expander_Active then
5890 if Is_OK_Static_Expression (L) then
5891 Fold_Uint (L, Expr_Value (L), Is_Static_Expression (L));
5892 end if;
5894 if Is_OK_Static_Expression (H) then
5895 Fold_Uint (H, Expr_Value (H), Is_Static_Expression (H));
5896 end if;
5897 end if;
5898 end Resolve_Range;
5900 --------------------------
5901 -- Resolve_Real_Literal --
5902 --------------------------
5904 procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id) is
5905 Actual_Typ : constant Entity_Id := Etype (N);
5907 begin
5908 -- Special processing for fixed-point literals to make sure that the
5909 -- value is an exact multiple of small where this is required. We
5910 -- skip this for the universal real case, and also for generic types.
5912 if Is_Fixed_Point_Type (Typ)
5913 and then Typ /= Universal_Fixed
5914 and then Typ /= Any_Fixed
5915 and then not Is_Generic_Type (Typ)
5916 then
5917 declare
5918 Val : constant Ureal := Realval (N);
5919 Cintr : constant Ureal := Val / Small_Value (Typ);
5920 Cint : constant Uint := UR_Trunc (Cintr);
5921 Den : constant Uint := Norm_Den (Cintr);
5922 Stat : Boolean;
5924 begin
5925 -- Case of literal is not an exact multiple of the Small
5927 if Den /= 1 then
5929 -- For a source program literal for a decimal fixed-point
5930 -- type, this is statically illegal (RM 4.9(36)).
5932 if Is_Decimal_Fixed_Point_Type (Typ)
5933 and then Actual_Typ = Universal_Real
5934 and then Comes_From_Source (N)
5935 then
5936 Error_Msg_N ("value has extraneous low order digits", N);
5937 end if;
5939 -- Generate a warning if literal from source
5941 if Is_Static_Expression (N)
5942 and then Warn_On_Bad_Fixed_Value
5943 then
5944 Error_Msg_N
5945 ("static fixed-point value is not a multiple of Small?",
5946 N);
5947 end if;
5949 -- Replace literal by a value that is the exact representation
5950 -- of a value of the type, i.e. a multiple of the small value,
5951 -- by truncation, since Machine_Rounds is false for all GNAT
5952 -- fixed-point types (RM 4.9(38)).
5954 Stat := Is_Static_Expression (N);
5955 Rewrite (N,
5956 Make_Real_Literal (Sloc (N),
5957 Realval => Small_Value (Typ) * Cint));
5959 Set_Is_Static_Expression (N, Stat);
5960 end if;
5962 -- In all cases, set the corresponding integer field
5964 Set_Corresponding_Integer_Value (N, Cint);
5965 end;
5966 end if;
5968 -- Now replace the actual type by the expected type as usual
5970 Set_Etype (N, Typ);
5971 Eval_Real_Literal (N);
5972 end Resolve_Real_Literal;
5974 -----------------------
5975 -- Resolve_Reference --
5976 -----------------------
5978 procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id) is
5979 P : constant Node_Id := Prefix (N);
5981 begin
5982 -- Replace general access with specific type
5984 if Ekind (Etype (N)) = E_Allocator_Type then
5985 Set_Etype (N, Base_Type (Typ));
5986 end if;
5988 Resolve (P, Designated_Type (Etype (N)));
5990 -- If we are taking the reference of a volatile entity, then treat
5991 -- it as a potential modification of this entity. This is much too
5992 -- conservative, but is necessary because remove side effects can
5993 -- result in transformations of normal assignments into reference
5994 -- sequences that otherwise fail to notice the modification.
5996 if Is_Entity_Name (P) and then Treat_As_Volatile (Entity (P)) then
5997 Note_Possible_Modification (P);
5998 end if;
5999 end Resolve_Reference;
6001 --------------------------------
6002 -- Resolve_Selected_Component --
6003 --------------------------------
6005 procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id) is
6006 Comp : Entity_Id;
6007 Comp1 : Entity_Id := Empty; -- prevent junk warning
6008 P : constant Node_Id := Prefix (N);
6009 S : constant Node_Id := Selector_Name (N);
6010 T : Entity_Id := Etype (P);
6011 I : Interp_Index;
6012 I1 : Interp_Index := 0; -- prevent junk warning
6013 It : Interp;
6014 It1 : Interp;
6015 Found : Boolean;
6017 function Init_Component return Boolean;
6018 -- Check whether this is the initialization of a component within an
6019 -- init proc (by assignment or call to another init proc). If true,
6020 -- there is no need for a discriminant check.
6022 --------------------
6023 -- Init_Component --
6024 --------------------
6026 function Init_Component return Boolean is
6027 begin
6028 return Inside_Init_Proc
6029 and then Nkind (Prefix (N)) = N_Identifier
6030 and then Chars (Prefix (N)) = Name_uInit
6031 and then Nkind (Parent (Parent (N))) = N_Case_Statement_Alternative;
6032 end Init_Component;
6034 -- Start of processing for Resolve_Selected_Component
6036 begin
6037 if Is_Overloaded (P) then
6039 -- Use the context type to select the prefix that has a selector
6040 -- of the correct name and type.
6042 Found := False;
6043 Get_First_Interp (P, I, It);
6045 Search : while Present (It.Typ) loop
6046 if Is_Access_Type (It.Typ) then
6047 T := Designated_Type (It.Typ);
6048 else
6049 T := It.Typ;
6050 end if;
6052 if Is_Record_Type (T) then
6053 Comp := First_Entity (T);
6054 while Present (Comp) loop
6055 if Chars (Comp) = Chars (S)
6056 and then Covers (Etype (Comp), Typ)
6057 then
6058 if not Found then
6059 Found := True;
6060 I1 := I;
6061 It1 := It;
6062 Comp1 := Comp;
6064 else
6065 It := Disambiguate (P, I1, I, Any_Type);
6067 if It = No_Interp then
6068 Error_Msg_N
6069 ("ambiguous prefix for selected component", N);
6070 Set_Etype (N, Typ);
6071 return;
6073 else
6074 It1 := It;
6076 -- There may be an implicit dereference. Retrieve
6077 -- designated record type.
6079 if Is_Access_Type (It1.Typ) then
6080 T := Designated_Type (It1.Typ);
6081 else
6082 T := It1.Typ;
6083 end if;
6085 if Scope (Comp1) /= T then
6087 -- Resolution chooses the new interpretation.
6088 -- Find the component with the right name.
6090 Comp1 := First_Entity (T);
6091 while Present (Comp1)
6092 and then Chars (Comp1) /= Chars (S)
6093 loop
6094 Comp1 := Next_Entity (Comp1);
6095 end loop;
6096 end if;
6098 exit Search;
6099 end if;
6100 end if;
6101 end if;
6103 Comp := Next_Entity (Comp);
6104 end loop;
6106 end if;
6108 Get_Next_Interp (I, It);
6109 end loop Search;
6111 Resolve (P, It1.Typ);
6112 Set_Etype (N, Typ);
6113 Set_Entity (S, Comp1);
6115 else
6116 -- Resolve prefix with its type
6118 Resolve (P, T);
6119 end if;
6121 -- If prefix is an access type, the node will be transformed into an
6122 -- explicit dereference during expansion. The type of the node is the
6123 -- designated type of that of the prefix.
6125 if Is_Access_Type (Etype (P)) then
6126 T := Designated_Type (Etype (P));
6127 Check_Fully_Declared_Prefix (T, P);
6128 else
6129 T := Etype (P);
6130 end if;
6132 if Has_Discriminants (T)
6133 and then (Ekind (Entity (S)) = E_Component
6134 or else
6135 Ekind (Entity (S)) = E_Discriminant)
6136 and then Present (Original_Record_Component (Entity (S)))
6137 and then Ekind (Original_Record_Component (Entity (S))) = E_Component
6138 and then Present (Discriminant_Checking_Func
6139 (Original_Record_Component (Entity (S))))
6140 and then not Discriminant_Checks_Suppressed (T)
6141 and then not Init_Component
6142 then
6143 Set_Do_Discriminant_Check (N);
6144 end if;
6146 if Ekind (Entity (S)) = E_Void then
6147 Error_Msg_N ("premature use of component", S);
6148 end if;
6150 -- If the prefix is a record conversion, this may be a renamed
6151 -- discriminant whose bounds differ from those of the original
6152 -- one, so we must ensure that a range check is performed.
6154 if Nkind (P) = N_Type_Conversion
6155 and then Ekind (Entity (S)) = E_Discriminant
6156 and then Is_Discrete_Type (Typ)
6157 then
6158 Set_Etype (N, Base_Type (Typ));
6159 end if;
6161 -- Note: No Eval processing is required, because the prefix is of a
6162 -- record type, or protected type, and neither can possibly be static.
6164 end Resolve_Selected_Component;
6166 -------------------
6167 -- Resolve_Shift --
6168 -------------------
6170 procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id) is
6171 B_Typ : constant Entity_Id := Base_Type (Typ);
6172 L : constant Node_Id := Left_Opnd (N);
6173 R : constant Node_Id := Right_Opnd (N);
6175 begin
6176 -- We do the resolution using the base type, because intermediate values
6177 -- in expressions always are of the base type, not a subtype of it.
6179 Resolve (L, B_Typ);
6180 Resolve (R, Standard_Natural);
6182 Check_Unset_Reference (L);
6183 Check_Unset_Reference (R);
6185 Set_Etype (N, B_Typ);
6186 Generate_Operator_Reference (N, B_Typ);
6187 Eval_Shift (N);
6188 end Resolve_Shift;
6190 ---------------------------
6191 -- Resolve_Short_Circuit --
6192 ---------------------------
6194 procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id) is
6195 B_Typ : constant Entity_Id := Base_Type (Typ);
6196 L : constant Node_Id := Left_Opnd (N);
6197 R : constant Node_Id := Right_Opnd (N);
6199 begin
6200 Resolve (L, B_Typ);
6201 Resolve (R, B_Typ);
6203 Check_Unset_Reference (L);
6204 Check_Unset_Reference (R);
6206 Set_Etype (N, B_Typ);
6207 Eval_Short_Circuit (N);
6208 end Resolve_Short_Circuit;
6210 -------------------
6211 -- Resolve_Slice --
6212 -------------------
6214 procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id) is
6215 Name : constant Node_Id := Prefix (N);
6216 Drange : constant Node_Id := Discrete_Range (N);
6217 Array_Type : Entity_Id := Empty;
6218 Index : Node_Id;
6220 begin
6221 if Is_Overloaded (Name) then
6223 -- Use the context type to select the prefix that yields the
6224 -- correct array type.
6226 declare
6227 I : Interp_Index;
6228 I1 : Interp_Index := 0;
6229 It : Interp;
6230 P : constant Node_Id := Prefix (N);
6231 Found : Boolean := False;
6233 begin
6234 Get_First_Interp (P, I, It);
6235 while Present (It.Typ) loop
6236 if (Is_Array_Type (It.Typ)
6237 and then Covers (Typ, It.Typ))
6238 or else (Is_Access_Type (It.Typ)
6239 and then Is_Array_Type (Designated_Type (It.Typ))
6240 and then Covers (Typ, Designated_Type (It.Typ)))
6241 then
6242 if Found then
6243 It := Disambiguate (P, I1, I, Any_Type);
6245 if It = No_Interp then
6246 Error_Msg_N ("ambiguous prefix for slicing", N);
6247 Set_Etype (N, Typ);
6248 return;
6249 else
6250 Found := True;
6251 Array_Type := It.Typ;
6252 I1 := I;
6253 end if;
6254 else
6255 Found := True;
6256 Array_Type := It.Typ;
6257 I1 := I;
6258 end if;
6259 end if;
6261 Get_Next_Interp (I, It);
6262 end loop;
6263 end;
6265 else
6266 Array_Type := Etype (Name);
6267 end if;
6269 Resolve (Name, Array_Type);
6271 if Is_Access_Type (Array_Type) then
6272 Apply_Access_Check (N);
6273 Array_Type := Designated_Type (Array_Type);
6275 -- If the prefix is an access to an unconstrained array, we must use
6276 -- the actual subtype of the object to perform the index checks. The
6277 -- object denoted by the prefix is implicit in the node, so we build
6278 -- an explicit representation for it in order to compute the actual
6279 -- subtype.
6281 if not Is_Constrained (Array_Type) then
6282 Remove_Side_Effects (Prefix (N));
6284 declare
6285 Obj : constant Node_Id :=
6286 Make_Explicit_Dereference (Sloc (N),
6287 Prefix => New_Copy_Tree (Prefix (N)));
6288 begin
6289 Set_Etype (Obj, Array_Type);
6290 Set_Parent (Obj, Parent (N));
6291 Array_Type := Get_Actual_Subtype (Obj);
6292 end;
6293 end if;
6295 elsif Is_Entity_Name (Name)
6296 or else (Nkind (Name) = N_Function_Call
6297 and then not Is_Constrained (Etype (Name)))
6298 then
6299 Array_Type := Get_Actual_Subtype (Name);
6300 end if;
6302 -- If name was overloaded, set slice type correctly now
6304 Set_Etype (N, Array_Type);
6306 -- If the range is specified by a subtype mark, no resolution is
6307 -- necessary. Else resolve the bounds, and apply needed checks.
6309 if not Is_Entity_Name (Drange) then
6310 Index := First_Index (Array_Type);
6311 Resolve (Drange, Base_Type (Etype (Index)));
6313 if Nkind (Drange) = N_Range then
6314 Apply_Range_Check (Drange, Etype (Index));
6315 end if;
6316 end if;
6318 Set_Slice_Subtype (N);
6319 Eval_Slice (N);
6320 end Resolve_Slice;
6322 ----------------------------
6323 -- Resolve_String_Literal --
6324 ----------------------------
6326 procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id) is
6327 C_Typ : constant Entity_Id := Component_Type (Typ);
6328 R_Typ : constant Entity_Id := Root_Type (C_Typ);
6329 Loc : constant Source_Ptr := Sloc (N);
6330 Str : constant String_Id := Strval (N);
6331 Strlen : constant Nat := String_Length (Str);
6332 Subtype_Id : Entity_Id;
6333 Need_Check : Boolean;
6335 begin
6336 -- For a string appearing in a concatenation, defer creation of the
6337 -- string_literal_subtype until the end of the resolution of the
6338 -- concatenation, because the literal may be constant-folded away. This
6339 -- is a useful optimization for long concatenation expressions.
6341 -- If the string is an aggregate built for a single character (which
6342 -- happens in a non-static context) or a is null string to which special
6343 -- checks may apply, we build the subtype. Wide strings must also get a
6344 -- string subtype if they come from a one character aggregate. Strings
6345 -- generated by attributes might be static, but it is often hard to
6346 -- determine whether the enclosing context is static, so we generate
6347 -- subtypes for them as well, thus losing some rarer optimizations ???
6348 -- Same for strings that come from a static conversion.
6350 Need_Check :=
6351 (Strlen = 0 and then Typ /= Standard_String)
6352 or else Nkind (Parent (N)) /= N_Op_Concat
6353 or else (N /= Left_Opnd (Parent (N))
6354 and then N /= Right_Opnd (Parent (N)))
6355 or else ((Typ = Standard_Wide_String
6356 or else Typ = Standard_Wide_Wide_String)
6357 and then Nkind (Original_Node (N)) /= N_String_Literal);
6359 -- If the resolving type is itself a string literal subtype, we
6360 -- can just reuse it, since there is no point in creating another.
6362 if Ekind (Typ) = E_String_Literal_Subtype then
6363 Subtype_Id := Typ;
6365 elsif Nkind (Parent (N)) = N_Op_Concat
6366 and then not Need_Check
6367 and then Nkind (Original_Node (N)) /= N_Character_Literal
6368 and then Nkind (Original_Node (N)) /= N_Attribute_Reference
6369 and then Nkind (Original_Node (N)) /= N_Qualified_Expression
6370 and then Nkind (Original_Node (N)) /= N_Type_Conversion
6371 then
6372 Subtype_Id := Typ;
6374 -- Otherwise we must create a string literal subtype. Note that the
6375 -- whole idea of string literal subtypes is simply to avoid the need
6376 -- for building a full fledged array subtype for each literal.
6377 else
6378 Set_String_Literal_Subtype (N, Typ);
6379 Subtype_Id := Etype (N);
6380 end if;
6382 if Nkind (Parent (N)) /= N_Op_Concat
6383 or else Need_Check
6384 then
6385 Set_Etype (N, Subtype_Id);
6386 Eval_String_Literal (N);
6387 end if;
6389 if Is_Limited_Composite (Typ)
6390 or else Is_Private_Composite (Typ)
6391 then
6392 Error_Msg_N ("string literal not available for private array", N);
6393 Set_Etype (N, Any_Type);
6394 return;
6395 end if;
6397 -- The validity of a null string has been checked in the
6398 -- call to Eval_String_Literal.
6400 if Strlen = 0 then
6401 return;
6403 -- Always accept string literal with component type Any_Character, which
6404 -- occurs in error situations and in comparisons of literals, both of
6405 -- which should accept all literals.
6407 elsif R_Typ = Any_Character then
6408 return;
6410 -- If the type is bit-packed, then we always tranform the string literal
6411 -- into a full fledged aggregate.
6413 elsif Is_Bit_Packed_Array (Typ) then
6414 null;
6416 -- Deal with cases of Wide_Wide_String, Wide_String, and String
6418 else
6419 -- For Standard.Wide_Wide_String, or any other type whose component
6420 -- type is Standard.Wide_Wide_Character, we know that all the
6421 -- characters in the string must be acceptable, since the parser
6422 -- accepted the characters as valid character literals.
6424 if R_Typ = Standard_Wide_Wide_Character then
6425 null;
6427 -- For the case of Standard.String, or any other type whose component
6428 -- type is Standard.Character, we must make sure that there are no
6429 -- wide characters in the string, i.e. that it is entirely composed
6430 -- of characters in range of type Character.
6432 -- If the string literal is the result of a static concatenation, the
6433 -- test has already been performed on the components, and need not be
6434 -- repeated.
6436 elsif R_Typ = Standard_Character
6437 and then Nkind (Original_Node (N)) /= N_Op_Concat
6438 then
6439 for J in 1 .. Strlen loop
6440 if not In_Character_Range (Get_String_Char (Str, J)) then
6442 -- If we are out of range, post error. This is one of the
6443 -- very few places that we place the flag in the middle of
6444 -- a token, right under the offending wide character.
6446 Error_Msg
6447 ("literal out of range of type Standard.Character",
6448 Source_Ptr (Int (Loc) + J));
6449 return;
6450 end if;
6451 end loop;
6453 -- For the case of Standard.Wide_String, or any other type whose
6454 -- component type is Standard.Wide_Character, we must make sure that
6455 -- there are no wide characters in the string, i.e. that it is
6456 -- entirely composed of characters in range of type Wide_Character.
6458 -- If the string literal is the result of a static concatenation,
6459 -- the test has already been performed on the components, and need
6460 -- not be repeated.
6462 elsif R_Typ = Standard_Wide_Character
6463 and then Nkind (Original_Node (N)) /= N_Op_Concat
6464 then
6465 for J in 1 .. Strlen loop
6466 if not In_Wide_Character_Range (Get_String_Char (Str, J)) then
6468 -- If we are out of range, post error. This is one of the
6469 -- very few places that we place the flag in the middle of
6470 -- a token, right under the offending wide character.
6472 -- This is not quite right, because characters in general
6473 -- will take more than one character position ???
6475 Error_Msg
6476 ("literal out of range of type Standard.Wide_Character",
6477 Source_Ptr (Int (Loc) + J));
6478 return;
6479 end if;
6480 end loop;
6482 -- If the root type is not a standard character, then we will convert
6483 -- the string into an aggregate and will let the aggregate code do
6484 -- the checking. Standard Wide_Wide_Character is also OK here.
6486 else
6487 null;
6488 end if;
6490 -- See if the component type of the array corresponding to the string
6491 -- has compile time known bounds. If yes we can directly check
6492 -- whether the evaluation of the string will raise constraint error.
6493 -- Otherwise we need to transform the string literal into the
6494 -- corresponding character aggregate and let the aggregate
6495 -- code do the checking.
6497 if R_Typ = Standard_Character
6498 or else R_Typ = Standard_Wide_Character
6499 or else R_Typ = Standard_Wide_Wide_Character
6500 then
6501 -- Check for the case of full range, where we are definitely OK
6503 if Component_Type (Typ) = Base_Type (Component_Type (Typ)) then
6504 return;
6505 end if;
6507 -- Here the range is not the complete base type range, so check
6509 declare
6510 Comp_Typ_Lo : constant Node_Id :=
6511 Type_Low_Bound (Component_Type (Typ));
6512 Comp_Typ_Hi : constant Node_Id :=
6513 Type_High_Bound (Component_Type (Typ));
6515 Char_Val : Uint;
6517 begin
6518 if Compile_Time_Known_Value (Comp_Typ_Lo)
6519 and then Compile_Time_Known_Value (Comp_Typ_Hi)
6520 then
6521 for J in 1 .. Strlen loop
6522 Char_Val := UI_From_Int (Int (Get_String_Char (Str, J)));
6524 if Char_Val < Expr_Value (Comp_Typ_Lo)
6525 or else Char_Val > Expr_Value (Comp_Typ_Hi)
6526 then
6527 Apply_Compile_Time_Constraint_Error
6528 (N, "character out of range?", CE_Range_Check_Failed,
6529 Loc => Source_Ptr (Int (Loc) + J));
6530 end if;
6531 end loop;
6533 return;
6534 end if;
6535 end;
6536 end if;
6537 end if;
6539 -- If we got here we meed to transform the string literal into the
6540 -- equivalent qualified positional array aggregate. This is rather
6541 -- heavy artillery for this situation, but it is hard work to avoid.
6543 declare
6544 Lits : constant List_Id := New_List;
6545 P : Source_Ptr := Loc + 1;
6546 C : Char_Code;
6548 begin
6549 -- Build the character literals, we give them source locations that
6550 -- correspond to the string positions, which is a bit tricky given
6551 -- the possible presence of wide character escape sequences.
6553 for J in 1 .. Strlen loop
6554 C := Get_String_Char (Str, J);
6555 Set_Character_Literal_Name (C);
6557 Append_To (Lits,
6558 Make_Character_Literal (P,
6559 Chars => Name_Find,
6560 Char_Literal_Value => UI_From_CC (C)));
6562 if In_Character_Range (C) then
6563 P := P + 1;
6565 -- Should we have a call to Skip_Wide here ???
6566 -- ??? else
6567 -- Skip_Wide (P);
6569 end if;
6570 end loop;
6572 Rewrite (N,
6573 Make_Qualified_Expression (Loc,
6574 Subtype_Mark => New_Reference_To (Typ, Loc),
6575 Expression =>
6576 Make_Aggregate (Loc, Expressions => Lits)));
6578 Analyze_And_Resolve (N, Typ);
6579 end;
6580 end Resolve_String_Literal;
6582 -----------------------------
6583 -- Resolve_Subprogram_Info --
6584 -----------------------------
6586 procedure Resolve_Subprogram_Info (N : Node_Id; Typ : Entity_Id) is
6587 begin
6588 Set_Etype (N, Typ);
6589 end Resolve_Subprogram_Info;
6591 -----------------------------
6592 -- Resolve_Type_Conversion --
6593 -----------------------------
6595 procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id) is
6596 Conv_OK : constant Boolean := Conversion_OK (N);
6597 Target_Type : Entity_Id := Etype (N);
6598 Operand : Node_Id;
6599 Opnd_Type : Entity_Id;
6600 Rop : Node_Id;
6601 Orig_N : Node_Id;
6602 Orig_T : Node_Id;
6604 begin
6605 Operand := Expression (N);
6607 if not Conv_OK
6608 and then not Valid_Conversion (N, Target_Type, Operand)
6609 then
6610 return;
6611 end if;
6613 if Etype (Operand) = Any_Fixed then
6615 -- Mixed-mode operation involving a literal. Context must be a fixed
6616 -- type which is applied to the literal subsequently.
6618 if Is_Fixed_Point_Type (Typ) then
6619 Set_Etype (Operand, Universal_Real);
6621 elsif Is_Numeric_Type (Typ)
6622 and then (Nkind (Operand) = N_Op_Multiply
6623 or else Nkind (Operand) = N_Op_Divide)
6624 and then (Etype (Right_Opnd (Operand)) = Universal_Real
6625 or else Etype (Left_Opnd (Operand)) = Universal_Real)
6626 then
6627 -- Return if expression is ambiguous
6629 if Unique_Fixed_Point_Type (N) = Any_Type then
6630 return;
6632 -- If nothing else, the available fixed type is Duration
6634 else
6635 Set_Etype (Operand, Standard_Duration);
6636 end if;
6638 -- Resolve the real operand with largest available precision
6640 if Etype (Right_Opnd (Operand)) = Universal_Real then
6641 Rop := New_Copy_Tree (Right_Opnd (Operand));
6642 else
6643 Rop := New_Copy_Tree (Left_Opnd (Operand));
6644 end if;
6646 Resolve (Rop, Universal_Real);
6648 -- If the operand is a literal (it could be a non-static and
6649 -- illegal exponentiation) check whether the use of Duration
6650 -- is potentially inaccurate.
6652 if Nkind (Rop) = N_Real_Literal
6653 and then Realval (Rop) /= Ureal_0
6654 and then abs (Realval (Rop)) < Delta_Value (Standard_Duration)
6655 then
6656 Error_Msg_N ("universal real operand can only be interpreted?",
6657 Rop);
6659 end if;
6661 elsif Is_Numeric_Type (Typ)
6662 and then Nkind (Operand) in N_Op
6663 and then Unique_Fixed_Point_Type (N) /= Any_Type
6664 then
6665 Set_Etype (Operand, Standard_Duration);
6667 else
6668 Error_Msg_N ("invalid context for mixed mode operation", N);
6669 Set_Etype (Operand, Any_Type);
6670 return;
6671 end if;
6672 end if;
6674 Opnd_Type := Etype (Operand);
6675 Resolve (Operand);
6677 -- Note: we do the Eval_Type_Conversion call before applying the
6678 -- required checks for a subtype conversion. This is important,
6679 -- since both are prepared under certain circumstances to change
6680 -- the type conversion to a constraint error node, but in the case
6681 -- of Eval_Type_Conversion this may reflect an illegality in the
6682 -- static case, and we would miss the illegality (getting only a
6683 -- warning message), if we applied the type conversion checks first.
6685 Eval_Type_Conversion (N);
6687 -- If after evaluation, we still have a type conversion, then we
6688 -- may need to apply checks required for a subtype conversion.
6690 -- Skip these type conversion checks if universal fixed operands
6691 -- operands involved, since range checks are handled separately for
6692 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
6694 if Nkind (N) = N_Type_Conversion
6695 and then not Is_Generic_Type (Root_Type (Target_Type))
6696 and then Target_Type /= Universal_Fixed
6697 and then Opnd_Type /= Universal_Fixed
6698 then
6699 Apply_Type_Conversion_Checks (N);
6700 end if;
6702 -- Issue warning for conversion of simple object to its own type
6703 -- We have to test the original nodes, since they may have been
6704 -- rewritten by various optimizations.
6706 Orig_N := Original_Node (N);
6708 if Warn_On_Redundant_Constructs
6709 and then Comes_From_Source (Orig_N)
6710 and then Nkind (Orig_N) = N_Type_Conversion
6711 and then not In_Instance
6712 then
6713 Orig_N := Original_Node (Expression (Orig_N));
6714 Orig_T := Target_Type;
6716 -- If the node is part of a larger expression, the Target_Type
6717 -- may not be the original type of the node if the context is a
6718 -- condition. Recover original type to see if conversion is needed.
6720 if Is_Boolean_Type (Orig_T)
6721 and then Nkind (Parent (N)) in N_Op
6722 then
6723 Orig_T := Etype (Parent (N));
6724 end if;
6726 if Is_Entity_Name (Orig_N)
6727 and then Etype (Entity (Orig_N)) = Orig_T
6728 then
6729 Error_Msg_NE
6730 ("?useless conversion, & has this type", N, Entity (Orig_N));
6731 end if;
6732 end if;
6734 -- Ada 2005 (AI-251): Handle conversions to abstract interface types
6736 if Ada_Version >= Ada_05 then
6737 if Is_Access_Type (Target_Type) then
6738 Target_Type := Directly_Designated_Type (Target_Type);
6739 end if;
6741 if Is_Class_Wide_Type (Target_Type) then
6742 Target_Type := Etype (Target_Type);
6743 end if;
6745 if Is_Interface (Target_Type) then
6746 if Is_Access_Type (Opnd_Type) then
6747 Opnd_Type := Directly_Designated_Type (Opnd_Type);
6748 end if;
6750 declare
6751 Save_Typ : constant Entity_Id := Opnd_Type;
6753 begin
6754 if Is_Class_Wide_Type (Opnd_Type) then
6755 Opnd_Type := Etype (Opnd_Type);
6756 end if;
6758 -- Handle subtypes
6760 if Ekind (Opnd_Type) = E_Protected_Subtype
6761 or else Ekind (Opnd_Type) = E_Task_Subtype
6762 then
6763 Opnd_Type := Etype (Opnd_Type);
6764 end if;
6766 if not Interface_Present_In_Ancestor
6767 (Typ => Opnd_Type,
6768 Iface => Target_Type)
6769 then
6770 -- The static analysis is not enough to know if the
6771 -- interface is implemented or not. Hence we must pass the
6772 -- work to the expander to generate the required code to
6773 -- evaluate the conversion at run-time.
6775 if Is_Class_Wide_Type (Save_Typ)
6776 and then Is_Interface (Save_Typ)
6777 then
6778 Expand_Interface_Conversion (N, Is_Static => False);
6779 else
6780 Error_Msg_NE
6781 ("(Ada 2005) does not implement interface }",
6782 Operand, Target_Type);
6783 end if;
6785 else
6786 Expand_Interface_Conversion (N);
6787 end if;
6788 end;
6789 end if;
6790 end if;
6791 end Resolve_Type_Conversion;
6793 ----------------------
6794 -- Resolve_Unary_Op --
6795 ----------------------
6797 procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id) is
6798 B_Typ : constant Entity_Id := Base_Type (Typ);
6799 R : constant Node_Id := Right_Opnd (N);
6800 OK : Boolean;
6801 Lo : Uint;
6802 Hi : Uint;
6804 begin
6805 -- Generate warning for expressions like -5 mod 3
6807 if Paren_Count (N) = 0
6808 and then Nkind (N) = N_Op_Minus
6809 and then Paren_Count (Right_Opnd (N)) = 0
6810 and then Nkind (Right_Opnd (N)) = N_Op_Mod
6811 and then Comes_From_Source (N)
6812 then
6813 Error_Msg_N
6814 ("?unary minus expression should be parenthesized here", N);
6815 end if;
6817 if Comes_From_Source (N)
6818 and then Ekind (Entity (N)) = E_Function
6819 and then Is_Imported (Entity (N))
6820 and then Is_Intrinsic_Subprogram (Entity (N))
6821 then
6822 Resolve_Intrinsic_Unary_Operator (N, Typ);
6823 return;
6824 end if;
6826 if Etype (R) = Universal_Integer
6827 or else Etype (R) = Universal_Real
6828 then
6829 Check_For_Visible_Operator (N, B_Typ);
6830 end if;
6832 Set_Etype (N, B_Typ);
6833 Resolve (R, B_Typ);
6835 -- Generate warning for expressions like abs (x mod 2)
6837 if Warn_On_Redundant_Constructs
6838 and then Nkind (N) = N_Op_Abs
6839 then
6840 Determine_Range (Right_Opnd (N), OK, Lo, Hi);
6842 if OK and then Hi >= Lo and then Lo >= 0 then
6843 Error_Msg_N
6844 ("?abs applied to known non-negative value has no effect", N);
6845 end if;
6846 end if;
6848 Check_Unset_Reference (R);
6849 Generate_Operator_Reference (N, B_Typ);
6850 Eval_Unary_Op (N);
6852 -- Set overflow checking bit. Much cleverer code needed here eventually
6853 -- and perhaps the Resolve routines should be separated for the various
6854 -- arithmetic operations, since they will need different processing ???
6856 if Nkind (N) in N_Op then
6857 if not Overflow_Checks_Suppressed (Etype (N)) then
6858 Enable_Overflow_Check (N);
6859 end if;
6860 end if;
6861 end Resolve_Unary_Op;
6863 ----------------------------------
6864 -- Resolve_Unchecked_Expression --
6865 ----------------------------------
6867 procedure Resolve_Unchecked_Expression
6868 (N : Node_Id;
6869 Typ : Entity_Id)
6870 is
6871 begin
6872 Resolve (Expression (N), Typ, Suppress => All_Checks);
6873 Set_Etype (N, Typ);
6874 end Resolve_Unchecked_Expression;
6876 ---------------------------------------
6877 -- Resolve_Unchecked_Type_Conversion --
6878 ---------------------------------------
6880 procedure Resolve_Unchecked_Type_Conversion
6881 (N : Node_Id;
6882 Typ : Entity_Id)
6883 is
6884 pragma Warnings (Off, Typ);
6886 Operand : constant Node_Id := Expression (N);
6887 Opnd_Type : constant Entity_Id := Etype (Operand);
6889 begin
6890 -- Resolve operand using its own type
6892 Resolve (Operand, Opnd_Type);
6893 Eval_Unchecked_Conversion (N);
6895 end Resolve_Unchecked_Type_Conversion;
6897 ------------------------------
6898 -- Rewrite_Operator_As_Call --
6899 ------------------------------
6901 procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id) is
6902 Loc : constant Source_Ptr := Sloc (N);
6903 Actuals : constant List_Id := New_List;
6904 New_N : Node_Id;
6906 begin
6907 if Nkind (N) in N_Binary_Op then
6908 Append (Left_Opnd (N), Actuals);
6909 end if;
6911 Append (Right_Opnd (N), Actuals);
6913 New_N :=
6914 Make_Function_Call (Sloc => Loc,
6915 Name => New_Occurrence_Of (Nam, Loc),
6916 Parameter_Associations => Actuals);
6918 Preserve_Comes_From_Source (New_N, N);
6919 Preserve_Comes_From_Source (Name (New_N), N);
6920 Rewrite (N, New_N);
6921 Set_Etype (N, Etype (Nam));
6922 end Rewrite_Operator_As_Call;
6924 ------------------------------
6925 -- Rewrite_Renamed_Operator --
6926 ------------------------------
6928 procedure Rewrite_Renamed_Operator
6929 (N : Node_Id;
6930 Op : Entity_Id;
6931 Typ : Entity_Id)
6932 is
6933 Nam : constant Name_Id := Chars (Op);
6934 Is_Binary : constant Boolean := Nkind (N) in N_Binary_Op;
6935 Op_Node : Node_Id;
6937 begin
6938 -- Rewrite the operator node using the real operator, not its
6939 -- renaming. Exclude user-defined intrinsic operations of the same
6940 -- name, which are treated separately and rewritten as calls.
6942 if Ekind (Op) /= E_Function
6943 or else Chars (N) /= Nam
6944 then
6945 Op_Node := New_Node (Operator_Kind (Nam, Is_Binary), Sloc (N));
6946 Set_Chars (Op_Node, Nam);
6947 Set_Etype (Op_Node, Etype (N));
6948 Set_Entity (Op_Node, Op);
6949 Set_Right_Opnd (Op_Node, Right_Opnd (N));
6951 -- Indicate that both the original entity and its renaming
6952 -- are referenced at this point.
6954 Generate_Reference (Entity (N), N);
6955 Generate_Reference (Op, N);
6957 if Is_Binary then
6958 Set_Left_Opnd (Op_Node, Left_Opnd (N));
6959 end if;
6961 Rewrite (N, Op_Node);
6963 -- If the context type is private, add the appropriate conversions
6964 -- so that the operator is applied to the full view. This is done
6965 -- in the routines that resolve intrinsic operators,
6967 if Is_Intrinsic_Subprogram (Op)
6968 and then Is_Private_Type (Typ)
6969 then
6970 case Nkind (N) is
6971 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
6972 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
6973 Resolve_Intrinsic_Operator (N, Typ);
6975 when N_Op_Plus | N_Op_Minus | N_Op_Abs =>
6976 Resolve_Intrinsic_Unary_Operator (N, Typ);
6978 when others =>
6979 Resolve (N, Typ);
6980 end case;
6981 end if;
6983 elsif Ekind (Op) = E_Function
6984 and then Is_Intrinsic_Subprogram (Op)
6985 then
6986 -- Operator renames a user-defined operator of the same name. Use
6987 -- the original operator in the node, which is the one that gigi
6988 -- knows about.
6990 Set_Entity (N, Op);
6991 Set_Is_Overloaded (N, False);
6992 end if;
6993 end Rewrite_Renamed_Operator;
6995 -----------------------
6996 -- Set_Slice_Subtype --
6997 -----------------------
6999 -- Build an implicit subtype declaration to represent the type delivered
7000 -- by the slice. This is an abbreviated version of an array subtype. We
7001 -- define an index subtype for the slice, using either the subtype name
7002 -- or the discrete range of the slice. To be consistent with index usage
7003 -- elsewhere, we create a list header to hold the single index. This list
7004 -- is not otherwise attached to the syntax tree.
7006 procedure Set_Slice_Subtype (N : Node_Id) is
7007 Loc : constant Source_Ptr := Sloc (N);
7008 Index_List : constant List_Id := New_List;
7009 Index : Node_Id;
7010 Index_Subtype : Entity_Id;
7011 Index_Type : Entity_Id;
7012 Slice_Subtype : Entity_Id;
7013 Drange : constant Node_Id := Discrete_Range (N);
7015 begin
7016 if Is_Entity_Name (Drange) then
7017 Index_Subtype := Entity (Drange);
7019 else
7020 -- We force the evaluation of a range. This is definitely needed in
7021 -- the renamed case, and seems safer to do unconditionally. Note in
7022 -- any case that since we will create and insert an Itype referring
7023 -- to this range, we must make sure any side effect removal actions
7024 -- are inserted before the Itype definition.
7026 if Nkind (Drange) = N_Range then
7027 Force_Evaluation (Low_Bound (Drange));
7028 Force_Evaluation (High_Bound (Drange));
7029 end if;
7031 Index_Type := Base_Type (Etype (Drange));
7033 Index_Subtype := Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
7035 Set_Scalar_Range (Index_Subtype, Drange);
7036 Set_Etype (Index_Subtype, Index_Type);
7037 Set_Size_Info (Index_Subtype, Index_Type);
7038 Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
7039 end if;
7041 Slice_Subtype := Create_Itype (E_Array_Subtype, N);
7043 Index := New_Occurrence_Of (Index_Subtype, Loc);
7044 Set_Etype (Index, Index_Subtype);
7045 Append (Index, Index_List);
7047 Set_First_Index (Slice_Subtype, Index);
7048 Set_Etype (Slice_Subtype, Base_Type (Etype (N)));
7049 Set_Is_Constrained (Slice_Subtype, True);
7050 Init_Size_Align (Slice_Subtype);
7052 Check_Compile_Time_Size (Slice_Subtype);
7054 -- The Etype of the existing Slice node is reset to this slice
7055 -- subtype. Its bounds are obtained from its first index.
7057 Set_Etype (N, Slice_Subtype);
7059 -- In the packed case, this must be immediately frozen
7061 -- Couldn't we always freeze here??? and if we did, then the above
7062 -- call to Check_Compile_Time_Size could be eliminated, which would
7063 -- be nice, because then that routine could be made private to Freeze.
7065 if Is_Packed (Slice_Subtype) and not In_Default_Expression then
7066 Freeze_Itype (Slice_Subtype, N);
7067 end if;
7069 end Set_Slice_Subtype;
7071 --------------------------------
7072 -- Set_String_Literal_Subtype --
7073 --------------------------------
7075 procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id) is
7076 Loc : constant Source_Ptr := Sloc (N);
7077 Low_Bound : constant Node_Id :=
7078 Type_Low_Bound (Etype (First_Index (Typ)));
7079 Subtype_Id : Entity_Id;
7081 begin
7082 if Nkind (N) /= N_String_Literal then
7083 return;
7084 end if;
7086 Subtype_Id := Create_Itype (E_String_Literal_Subtype, N);
7087 Set_String_Literal_Length (Subtype_Id, UI_From_Int
7088 (String_Length (Strval (N))));
7089 Set_Etype (Subtype_Id, Base_Type (Typ));
7090 Set_Is_Constrained (Subtype_Id);
7091 Set_Etype (N, Subtype_Id);
7093 if Is_OK_Static_Expression (Low_Bound) then
7095 -- The low bound is set from the low bound of the corresponding
7096 -- index type. Note that we do not store the high bound in the
7097 -- string literal subtype, but it can be deduced if necessary
7098 -- from the length and the low bound.
7100 Set_String_Literal_Low_Bound (Subtype_Id, Low_Bound);
7102 else
7103 Set_String_Literal_Low_Bound
7104 (Subtype_Id, Make_Integer_Literal (Loc, 1));
7105 Set_Etype (String_Literal_Low_Bound (Subtype_Id), Standard_Positive);
7107 -- Build bona fide subtypes for the string, and wrap it in an
7108 -- unchecked conversion, because the backend expects the
7109 -- String_Literal_Subtype to have a static lower bound.
7111 declare
7112 Index_List : constant List_Id := New_List;
7113 Index_Type : constant Entity_Id := Etype (First_Index (Typ));
7114 High_Bound : constant Node_Id :=
7115 Make_Op_Add (Loc,
7116 Left_Opnd => New_Copy_Tree (Low_Bound),
7117 Right_Opnd =>
7118 Make_Integer_Literal (Loc,
7119 String_Length (Strval (N)) - 1));
7120 Array_Subtype : Entity_Id;
7121 Index_Subtype : Entity_Id;
7122 Drange : Node_Id;
7123 Index : Node_Id;
7125 begin
7126 Index_Subtype :=
7127 Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
7128 Drange := Make_Range (Loc, Low_Bound, High_Bound);
7129 Set_Scalar_Range (Index_Subtype, Drange);
7130 Set_Parent (Drange, N);
7131 Analyze_And_Resolve (Drange, Index_Type);
7133 Set_Etype (Index_Subtype, Index_Type);
7134 Set_Size_Info (Index_Subtype, Index_Type);
7135 Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
7137 Array_Subtype := Create_Itype (E_Array_Subtype, N);
7139 Index := New_Occurrence_Of (Index_Subtype, Loc);
7140 Set_Etype (Index, Index_Subtype);
7141 Append (Index, Index_List);
7143 Set_First_Index (Array_Subtype, Index);
7144 Set_Etype (Array_Subtype, Base_Type (Typ));
7145 Set_Is_Constrained (Array_Subtype, True);
7146 Init_Size_Align (Array_Subtype);
7148 Rewrite (N,
7149 Make_Unchecked_Type_Conversion (Loc,
7150 Subtype_Mark => New_Occurrence_Of (Array_Subtype, Loc),
7151 Expression => Relocate_Node (N)));
7152 Set_Etype (N, Array_Subtype);
7153 end;
7154 end if;
7155 end Set_String_Literal_Subtype;
7157 -----------------------------
7158 -- Unique_Fixed_Point_Type --
7159 -----------------------------
7161 function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id is
7162 T1 : Entity_Id := Empty;
7163 T2 : Entity_Id;
7164 Item : Node_Id;
7165 Scop : Entity_Id;
7167 procedure Fixed_Point_Error;
7168 -- If true ambiguity, give details
7170 -----------------------
7171 -- Fixed_Point_Error --
7172 -----------------------
7174 procedure Fixed_Point_Error is
7175 begin
7176 Error_Msg_N ("ambiguous universal_fixed_expression", N);
7179 end Fixed_Point_Error;
7181 -- Start of processing for Unique_Fixed_Point_Type
7183 begin
7184 -- The operations on Duration are visible, so Duration is always a
7185 -- possible interpretation.
7187 T1 := Standard_Duration;
7189 -- Look for fixed-point types in enclosing scopes
7191 Scop := Current_Scope;
7192 while Scop /= Standard_Standard loop
7193 T2 := First_Entity (Scop);
7194 while Present (T2) loop
7195 if Is_Fixed_Point_Type (T2)
7196 and then Current_Entity (T2) = T2
7197 and then Scope (Base_Type (T2)) = Scop
7198 then
7199 if Present (T1) then
7200 Fixed_Point_Error;
7201 return Any_Type;
7202 else
7203 T1 := T2;
7204 end if;
7205 end if;
7207 Next_Entity (T2);
7208 end loop;
7210 Scop := Scope (Scop);
7211 end loop;
7213 -- Look for visible fixed type declarations in the context
7215 Item := First (Context_Items (Cunit (Current_Sem_Unit)));
7216 while Present (Item) loop
7217 if Nkind (Item) = N_With_Clause then
7218 Scop := Entity (Name (Item));
7219 T2 := First_Entity (Scop);
7220 while Present (T2) loop
7221 if Is_Fixed_Point_Type (T2)
7222 and then Scope (Base_Type (T2)) = Scop
7223 and then (Is_Potentially_Use_Visible (T2)
7224 or else In_Use (T2))
7225 then
7226 if Present (T1) then
7227 Fixed_Point_Error;
7228 return Any_Type;
7229 else
7230 T1 := T2;
7231 end if;
7232 end if;
7234 Next_Entity (T2);
7235 end loop;
7236 end if;
7238 Next (Item);
7239 end loop;
7241 if Nkind (N) = N_Real_Literal then
7242 Error_Msg_NE ("real literal interpreted as }?", N, T1);
7244 else
7245 Error_Msg_NE ("universal_fixed expression interpreted as }?", N, T1);
7246 end if;
7248 return T1;
7249 end Unique_Fixed_Point_Type;
7251 ----------------------
7252 -- Valid_Conversion --
7253 ----------------------
7255 function Valid_Conversion
7256 (N : Node_Id;
7257 Target : Entity_Id;
7258 Operand : Node_Id) return Boolean
7259 is
7260 Target_Type : constant Entity_Id := Base_Type (Target);
7261 Opnd_Type : Entity_Id := Etype (Operand);
7263 function Conversion_Check
7264 (Valid : Boolean;
7265 Msg : String) return Boolean;
7266 -- Little routine to post Msg if Valid is False, returns Valid value
7268 function Valid_Tagged_Conversion
7269 (Target_Type : Entity_Id;
7270 Opnd_Type : Entity_Id) return Boolean;
7271 -- Specifically test for validity of tagged conversions
7273 ----------------------
7274 -- Conversion_Check --
7275 ----------------------
7277 function Conversion_Check
7278 (Valid : Boolean;
7279 Msg : String) return Boolean
7280 is
7281 begin
7282 if not Valid then
7283 Error_Msg_N (Msg, Operand);
7284 end if;
7286 return Valid;
7287 end Conversion_Check;
7289 -----------------------------
7290 -- Valid_Tagged_Conversion --
7291 -----------------------------
7293 function Valid_Tagged_Conversion
7294 (Target_Type : Entity_Id;
7295 Opnd_Type : Entity_Id) return Boolean
7296 is
7297 begin
7298 -- Upward conversions are allowed (RM 4.6(22))
7300 if Covers (Target_Type, Opnd_Type)
7301 or else Is_Ancestor (Target_Type, Opnd_Type)
7302 then
7303 return True;
7305 -- Downward conversion are allowed if the operand is class-wide
7306 -- (RM 4.6(23)).
7308 elsif Is_Class_Wide_Type (Opnd_Type)
7309 and then Covers (Opnd_Type, Target_Type)
7310 then
7311 return True;
7313 elsif Covers (Opnd_Type, Target_Type)
7314 or else Is_Ancestor (Opnd_Type, Target_Type)
7315 then
7316 return
7317 Conversion_Check (False,
7318 "downward conversion of tagged objects not allowed");
7320 -- Ada 2005 (AI-251): The conversion of a tagged type to an
7321 -- abstract interface type is always valid
7323 elsif Is_Interface (Target_Type) then
7324 return True;
7326 else
7327 Error_Msg_NE
7328 ("invalid tagged conversion, not compatible with}",
7329 N, First_Subtype (Opnd_Type));
7330 return False;
7331 end if;
7332 end Valid_Tagged_Conversion;
7334 -- Start of processing for Valid_Conversion
7336 begin
7337 Check_Parameterless_Call (Operand);
7339 if Is_Overloaded (Operand) then
7340 declare
7341 I : Interp_Index;
7342 I1 : Interp_Index;
7343 It : Interp;
7344 It1 : Interp;
7345 N1 : Entity_Id;
7347 begin
7348 -- Remove procedure calls, which syntactically cannot appear
7349 -- in this context, but which cannot be removed by type checking,
7350 -- because the context does not impose a type.
7352 -- When compiling for VMS, spurious ambiguities can be produced
7353 -- when arithmetic operations have a literal operand and return
7354 -- System.Address or a descendant of it. These ambiguities are
7355 -- otherwise resolved by the context, but for conversions there
7356 -- is no context type and the removal of the spurious operations
7357 -- must be done explicitly here.
7359 -- The node may be labelled overloaded, but still contain only
7360 -- one interpretation because others were discarded in previous
7361 -- filters. If this is the case, retain the single interpretation
7362 -- if legal.
7364 Get_First_Interp (Operand, I, It);
7365 Opnd_Type := It.Typ;
7366 Get_Next_Interp (I, It);
7368 if Present (It.Typ)
7369 and then Opnd_Type /= Standard_Void_Type
7370 then
7371 -- More than one candidate interpretation is available
7373 Get_First_Interp (Operand, I, It);
7374 while Present (It.Typ) loop
7375 if It.Typ = Standard_Void_Type then
7376 Remove_Interp (I);
7377 end if;
7379 if Present (System_Aux_Id)
7380 and then Is_Descendent_Of_Address (It.Typ)
7381 then
7382 Remove_Interp (I);
7383 end if;
7385 Get_Next_Interp (I, It);
7386 end loop;
7387 end if;
7389 Get_First_Interp (Operand, I, It);
7390 I1 := I;
7391 It1 := It;
7393 if No (It.Typ) then
7394 Error_Msg_N ("illegal operand in conversion", Operand);
7395 return False;
7396 end if;
7398 Get_Next_Interp (I, It);
7400 if Present (It.Typ) then
7401 N1 := It1.Nam;
7402 It1 := Disambiguate (Operand, I1, I, Any_Type);
7404 if It1 = No_Interp then
7405 Error_Msg_N ("ambiguous operand in conversion", Operand);
7407 Error_Msg_Sloc := Sloc (It.Nam);
7408 Error_Msg_N ("possible interpretation#!", Operand);
7410 Error_Msg_Sloc := Sloc (N1);
7411 Error_Msg_N ("possible interpretation#!", Operand);
7413 return False;
7414 end if;
7415 end if;
7417 Set_Etype (Operand, It1.Typ);
7418 Opnd_Type := It1.Typ;
7419 end;
7420 end if;
7422 if Chars (Current_Scope) = Name_Unchecked_Conversion then
7424 -- This check is dubious, what if there were a user defined
7425 -- scope whose name was Unchecked_Conversion ???
7427 return True;
7429 elsif Is_Numeric_Type (Target_Type) then
7430 if Opnd_Type = Universal_Fixed then
7431 return True;
7433 elsif (In_Instance or else In_Inlined_Body)
7434 and then not Comes_From_Source (N)
7435 then
7436 return True;
7438 else
7439 return Conversion_Check (Is_Numeric_Type (Opnd_Type),
7440 "illegal operand for numeric conversion");
7441 end if;
7443 elsif Is_Array_Type (Target_Type) then
7444 if not Is_Array_Type (Opnd_Type)
7445 or else Opnd_Type = Any_Composite
7446 or else Opnd_Type = Any_String
7447 then
7448 Error_Msg_N
7449 ("illegal operand for array conversion", Operand);
7450 return False;
7452 elsif Number_Dimensions (Target_Type) /=
7453 Number_Dimensions (Opnd_Type)
7454 then
7455 Error_Msg_N
7456 ("incompatible number of dimensions for conversion", Operand);
7457 return False;
7459 else
7460 declare
7461 Target_Index : Node_Id := First_Index (Target_Type);
7462 Opnd_Index : Node_Id := First_Index (Opnd_Type);
7464 Target_Index_Type : Entity_Id;
7465 Opnd_Index_Type : Entity_Id;
7467 Target_Comp_Type : constant Entity_Id :=
7468 Component_Type (Target_Type);
7469 Opnd_Comp_Type : constant Entity_Id :=
7470 Component_Type (Opnd_Type);
7472 begin
7473 while Present (Target_Index) and then Present (Opnd_Index) loop
7474 Target_Index_Type := Etype (Target_Index);
7475 Opnd_Index_Type := Etype (Opnd_Index);
7477 if not (Is_Integer_Type (Target_Index_Type)
7478 and then Is_Integer_Type (Opnd_Index_Type))
7479 and then (Root_Type (Target_Index_Type)
7480 /= Root_Type (Opnd_Index_Type))
7481 then
7482 Error_Msg_N
7483 ("incompatible index types for array conversion",
7484 Operand);
7485 return False;
7486 end if;
7488 Next_Index (Target_Index);
7489 Next_Index (Opnd_Index);
7490 end loop;
7492 declare
7493 BT : constant Entity_Id := Base_Type (Target_Comp_Type);
7494 BO : constant Entity_Id := Base_Type (Opnd_Comp_Type);
7496 begin
7497 if BT = BO then
7498 null;
7500 elsif
7501 (Ekind (BT) = E_Anonymous_Access_Type
7502 or else Ekind (BT) = E_Anonymous_Access_Subprogram_Type)
7503 and then Ekind (BO) = Ekind (BT)
7504 and then Subtypes_Statically_Match
7505 (Target_Comp_Type, Opnd_Comp_Type)
7506 then
7507 null;
7509 else
7510 Error_Msg_N
7511 ("incompatible component types for array conversion",
7512 Operand);
7513 return False;
7514 end if;
7515 end;
7517 if Is_Constrained (Target_Comp_Type) /=
7518 Is_Constrained (Opnd_Comp_Type)
7519 or else not Subtypes_Statically_Match
7520 (Target_Comp_Type, Opnd_Comp_Type)
7521 then
7522 Error_Msg_N
7523 ("component subtypes must statically match", Operand);
7524 return False;
7526 end if;
7527 end;
7528 end if;
7530 return True;
7532 -- Ada 2005 (AI-251)
7534 elsif (Ekind (Target_Type) = E_General_Access_Type
7535 or else Ekind (Target_Type) = E_Anonymous_Access_Type)
7536 and then Is_Interface (Directly_Designated_Type (Target_Type))
7537 then
7538 -- Check the static accessibility rule of 4.6(17). Note that the
7539 -- check is not enforced when within an instance body, since the RM
7540 -- requires such cases to be caught at run time.
7542 if Ekind (Target_Type) /= E_Anonymous_Access_Type then
7543 if Type_Access_Level (Opnd_Type) >
7544 Type_Access_Level (Target_Type)
7545 then
7546 -- In an instance, this is a run-time check, but one we know
7547 -- will fail, so generate an appropriate warning. The raise
7548 -- will be generated by Expand_N_Type_Conversion.
7550 if In_Instance_Body then
7551 Error_Msg_N
7552 ("?cannot convert local pointer to non-local access type",
7553 Operand);
7554 Error_Msg_N
7556 else
7557 Error_Msg_N
7558 ("cannot convert local pointer to non-local access type",
7559 Operand);
7560 return False;
7561 end if;
7563 -- Special accessibility checks are needed in the case of access
7564 -- discriminants declared for a limited type.
7566 elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type
7567 and then not Is_Local_Anonymous_Access (Opnd_Type)
7568 then
7569 -- When the operand is a selected access discriminant the check
7570 -- needs to be made against the level of the object denoted by
7571 -- the prefix of the selected name. (Object_Access_Level
7572 -- handles checking the prefix of the operand for this case.)
7574 if Nkind (Operand) = N_Selected_Component
7575 and then Object_Access_Level (Operand) >
7576 Type_Access_Level (Target_Type)
7577 then
7578 -- In an instance, this is a run-time check, but one we
7579 -- know will fail, so generate an appropriate warning.
7580 -- The raise will be generated by Expand_N_Type_Conversion.
7582 if In_Instance_Body then
7583 Error_Msg_N
7584 ("?cannot convert access discriminant to non-local" &
7585 " access type", Operand);
7586 Error_Msg_N
7588 else
7589 Error_Msg_N
7590 ("cannot convert access discriminant to non-local" &
7591 " access type", Operand);
7592 return False;
7593 end if;
7594 end if;
7596 -- The case of a reference to an access discriminant from
7597 -- within a limited type declaration (which will appear as
7598 -- a discriminal) is always illegal because the level of the
7599 -- discriminant is considered to be deeper than any (namable)
7600 -- access type.
7602 if Is_Entity_Name (Operand)
7603 and then not Is_Local_Anonymous_Access (Opnd_Type)
7604 and then (Ekind (Entity (Operand)) = E_In_Parameter
7605 or else Ekind (Entity (Operand)) = E_Constant)
7606 and then Present (Discriminal_Link (Entity (Operand)))
7607 then
7608 Error_Msg_N
7609 ("discriminant has deeper accessibility level than target",
7610 Operand);
7611 return False;
7612 end if;
7613 end if;
7614 end if;
7616 return True;
7618 elsif (Ekind (Target_Type) = E_General_Access_Type
7619 or else Ekind (Target_Type) = E_Anonymous_Access_Type)
7620 and then
7621 Conversion_Check
7622 (Is_Access_Type (Opnd_Type)
7623 and then Ekind (Opnd_Type) /=
7624 E_Access_Subprogram_Type
7625 and then Ekind (Opnd_Type) /=
7626 E_Access_Protected_Subprogram_Type,
7627 "must be an access-to-object type")
7628 then
7629 if Is_Access_Constant (Opnd_Type)
7630 and then not Is_Access_Constant (Target_Type)
7631 then
7632 Error_Msg_N
7633 ("access-to-constant operand type not allowed", Operand);
7634 return False;
7635 end if;
7637 -- Check the static accessibility rule of 4.6(17). Note that the
7638 -- check is not enforced when within an instance body, since the RM
7639 -- requires such cases to be caught at run time.
7641 if Ekind (Target_Type) /= E_Anonymous_Access_Type
7642 or else Is_Local_Anonymous_Access (Target_Type)
7643 then
7644 if Type_Access_Level (Opnd_Type)
7645 > Type_Access_Level (Target_Type)
7646 then
7647 -- In an instance, this is a run-time check, but one we
7648 -- know will fail, so generate an appropriate warning.
7649 -- The raise will be generated by Expand_N_Type_Conversion.
7651 if In_Instance_Body then
7652 Error_Msg_N
7653 ("?cannot convert local pointer to non-local access type",
7654 Operand);
7655 Error_Msg_N
7658 else
7659 Error_Msg_N
7660 ("cannot convert local pointer to non-local access type",
7661 Operand);
7662 return False;
7663 end if;
7665 -- Special accessibility checks are needed in the case of access
7666 -- discriminants declared for a limited type.
7668 elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type
7669 and then not Is_Local_Anonymous_Access (Opnd_Type)
7670 then
7672 -- When the operand is a selected access discriminant the check
7673 -- needs to be made against the level of the object denoted by
7674 -- the prefix of the selected name. (Object_Access_Level
7675 -- handles checking the prefix of the operand for this case.)
7677 if Nkind (Operand) = N_Selected_Component
7678 and then Object_Access_Level (Operand)
7679 > Type_Access_Level (Target_Type)
7680 then
7681 -- In an instance, this is a run-time check, but one we
7682 -- know will fail, so generate an appropriate warning.
7683 -- The raise will be generated by Expand_N_Type_Conversion.
7685 if In_Instance_Body then
7686 Error_Msg_N
7687 ("?cannot convert access discriminant to non-local" &
7688 " access type", Operand);
7689 Error_Msg_N
7691 Operand);
7693 else
7694 Error_Msg_N
7695 ("cannot convert access discriminant to non-local" &
7696 " access type", Operand);
7697 return False;
7698 end if;
7699 end if;
7701 -- The case of a reference to an access discriminant from
7702 -- within a limited type declaration (which will appear as
7703 -- a discriminal) is always illegal because the level of the
7704 -- discriminant is considered to be deeper than any (namable)
7705 -- access type.
7707 if Is_Entity_Name (Operand)
7708 and then (Ekind (Entity (Operand)) = E_In_Parameter
7709 or else Ekind (Entity (Operand)) = E_Constant)
7710 and then Present (Discriminal_Link (Entity (Operand)))
7711 then
7712 Error_Msg_N
7713 ("discriminant has deeper accessibility level than target",
7714 Operand);
7715 return False;
7716 end if;
7717 end if;
7718 end if;
7720 declare
7721 Target : constant Entity_Id := Designated_Type (Target_Type);
7722 Opnd : constant Entity_Id := Designated_Type (Opnd_Type);
7724 begin
7725 if Is_Tagged_Type (Target) then
7726 return Valid_Tagged_Conversion (Target, Opnd);
7728 else
7729 if Base_Type (Target) /= Base_Type (Opnd) then
7730 Error_Msg_NE
7731 ("target designated type not compatible with }",
7732 N, Base_Type (Opnd));
7733 return False;
7735 -- Ada 2005 AI-384: legality rule is symmetric in both
7736 -- designated types. The conversion is legal (with possible
7737 -- constraint check) if either designated type is
7738 -- unconstrained.
7740 elsif Subtypes_Statically_Match (Target, Opnd)
7741 or else
7742 (Has_Discriminants (Target)
7743 and then
7744 (not Is_Constrained (Opnd)
7745 or else not Is_Constrained (Target)))
7746 then
7747 return True;
7749 else
7750 Error_Msg_NE
7751 ("target designated subtype not compatible with }",
7752 N, Opnd);
7753 return False;
7754 end if;
7755 end if;
7756 end;
7758 elsif (Ekind (Target_Type) = E_Access_Subprogram_Type
7759 or else
7760 Ekind (Target_Type) = E_Anonymous_Access_Subprogram_Type)
7761 and then No (Corresponding_Remote_Type (Opnd_Type))
7762 and then Conversion_Check
7763 (Ekind (Base_Type (Opnd_Type)) = E_Access_Subprogram_Type,
7764 "illegal operand for access subprogram conversion")
7765 then
7766 -- Check that the designated types are subtype conformant
7768 Check_Subtype_Conformant (New_Id => Designated_Type (Target_Type),
7769 Old_Id => Designated_Type (Opnd_Type),
7770 Err_Loc => N);
7772 -- Check the static accessibility rule of 4.6(20)
7774 if Type_Access_Level (Opnd_Type) >
7775 Type_Access_Level (Target_Type)
7776 then
7777 Error_Msg_N
7778 ("operand type has deeper accessibility level than target",
7779 Operand);
7781 -- Check that if the operand type is declared in a generic body,
7782 -- then the target type must be declared within that same body
7783 -- (enforces last sentence of 4.6(20)).
7785 elsif Present (Enclosing_Generic_Body (Opnd_Type)) then
7786 declare
7787 O_Gen : constant Node_Id :=
7788 Enclosing_Generic_Body (Opnd_Type);
7790 T_Gen : Node_Id;
7792 begin
7793 T_Gen := Enclosing_Generic_Body (Target_Type);
7794 while Present (T_Gen) and then T_Gen /= O_Gen loop
7795 T_Gen := Enclosing_Generic_Body (T_Gen);
7796 end loop;
7798 if T_Gen /= O_Gen then
7799 Error_Msg_N
7800 ("target type must be declared in same generic body"
7801 & " as operand type", N);
7802 end if;
7803 end;
7804 end if;
7806 return True;
7808 elsif Is_Remote_Access_To_Subprogram_Type (Target_Type)
7809 and then Is_Remote_Access_To_Subprogram_Type (Opnd_Type)
7810 then
7811 -- It is valid to convert from one RAS type to another provided
7812 -- that their specification statically match.
7814 Check_Subtype_Conformant
7815 (New_Id =>
7816 Designated_Type (Corresponding_Remote_Type (Target_Type)),
7817 Old_Id =>
7818 Designated_Type (Corresponding_Remote_Type (Opnd_Type)),
7819 Err_Loc =>
7820 N);
7821 return True;
7823 elsif Is_Tagged_Type (Target_Type) then
7824 return Valid_Tagged_Conversion (Target_Type, Opnd_Type);
7826 -- Types derived from the same root type are convertible
7828 elsif Root_Type (Target_Type) = Root_Type (Opnd_Type) then
7829 return True;
7831 -- In an instance, there may be inconsistent views of the same
7832 -- type, or types derived from the same type.
7834 elsif In_Instance
7835 and then Underlying_Type (Target_Type) = Underlying_Type (Opnd_Type)
7836 then
7837 return True;
7839 -- Special check for common access type error case
7841 elsif Ekind (Target_Type) = E_Access_Type
7842 and then Is_Access_Type (Opnd_Type)
7843 then
7844 Error_Msg_N ("target type must be general access type!", N);
7845 Error_Msg_NE ("add ALL to }!", N, Target_Type);
7847 return False;
7849 else
7850 Error_Msg_NE ("invalid conversion, not compatible with }",
7851 N, Opnd_Type);
7853 return False;
7854 end if;
7855 end Valid_Conversion;
7857 end Sem_Res;