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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) 1992-2003, 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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 ------------------------------------------------------------------------------
74 -----------------------
75 -- Local Subprograms --
76 -----------------------
78 -- Second pass (top-down) type checking and overload resolution procedures
79 -- Typ is the type required by context. These procedures propagate the
80 -- type information recursively to the descendants of N. If the node
81 -- is not overloaded, its Etype is established in the first pass. If
82 -- overloaded, the Resolve routines set the correct type. For arith.
83 -- operators, the Etype is the base type of the context.
85 -- Note that Resolve_Attribute is separated off in Sem_Attr
88 -- Give list of candidate interpretations when a character literal cannot
89 -- be resolved.
92 -- N is a binary operator node which may possibly operate on Boolean
93 -- operands. If the operator does have Boolean operands, then a call is
94 -- made to check the restriction No_Direct_Boolean_Operators.
97 -- Enforce the restrictions on the use of discriminants when constraining
98 -- a component of a discriminated type (record or concurrent type).
101 -- Given a node for an operator associated with type T, check that
102 -- the operator is visible. Operators all of whose operands are
103 -- universal must be checked for visibility during resolution
104 -- because their type is not determinable based on their operands.
107 -- Given a call node, N, which is known to occur immediately within the
108 -- subprogram being called, determines whether it is a detectable case of
109 -- an infinite recursion, and if so, outputs appropriate messages. Returns
110 -- True if an infinite recursion is detected, and False otherwise.
113 -- If the type of the object being initialized uses the secondary stack
114 -- directly or indirectly, create a transient scope for the call to the
115 -- init proc. This is because we do not create transient scopes for the
116 -- initialization of individual components within the init proc itself.
117 -- Could be optimized away perhaps?
120 -- Utility to check whether the name in the call is a predefined
121 -- operator, in which case the call is made into an operator node.
122 -- An instance of an intrinsic conversion operation may be given
123 -- an operator name, but is not treated like an operator.
126 -- If a default expression in entry call N depends on the discriminants
127 -- of the task, it must be replaced with a reference to the discriminant
128 -- of the task being called.
163 function Operator_Kind
167 -- Utility to map the name of an operator into the corresponding Node. Used
168 -- by other node rewriting procedures.
171 -- Resolve actuals of call, and add default expressions for missing ones.
174 -- Called from Resolve_Call, when the prefix denotes an entry or element
175 -- of entry family. Actuals are resolved as for subprograms, and the node
176 -- is rebuilt as an entry call. Also called for protected operations. Typ
177 -- is the context type, which is used when the operation is a protected
178 -- function with no arguments, and the return value is indexed.
181 -- A call to a user-defined intrinsic operator is rewritten as a call
182 -- to the corresponding predefined operator, with suitable conversions.
185 -- Ditto, for unary operators (only arithmetic ones).
188 -- If an operator node resolves to a call to a user-defined operator,
189 -- rewrite the node as a function call.
191 procedure Make_Call_Into_Operator
195 -- Inverse transformation: if an operator is given in functional notation,
196 -- then after resolving the node, transform into an operator node, so
197 -- that operands are resolved properly. Recall that predefined operators
198 -- do not have a full signature and special resolution rules apply.
201 -- An operator can rename another, e.g. in an instantiation. In that
202 -- case, the proper operator node must be constructed.
205 -- The String_Literal_Subtype is built for all strings that are not
206 -- operands of a static concatenation operation. If the argument is
207 -- not a N_String_Literal node, then the call has no effect.
210 -- Build subtype of array type, with the range specified by the slice
213 -- A universal_fixed expression in an universal context is unambiguous
214 -- if there is only one applicable fixed point type. Determining whether
215 -- there is only one requires a search over all visible entities, and
216 -- happens only in very pathological cases (see 6115-006).
218 function Valid_Conversion
223 -- Verify legality rules given in 4.6 (8-23). Target is the target
224 -- type of the conversion, which may be an implicit conversion of
225 -- an actual parameter to an anonymous access type (in which case
226 -- N denotes the actual parameter and N = Operand).
228 -------------------------
229 -- Ambiguous_Character --
230 -------------------------
235 begin
238 Error_Msg_N
253 -------------------------
254 -- Analyze_And_Resolve --
255 -------------------------
258 begin
264 begin
269 -- Version withs check(s) suppressed
271 procedure Analyze_And_Resolve
275 is
278 begin
280 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
325 begin
331 else
332 declare
335 begin
343 and then Scope_Is_Transient
344 then
346 Scope_Suppress;
350 -----------------------------
351 -- Check_Direct_Boolean_Op --
352 -----------------------------
355 begin
361 ----------------------------
362 -- Check_Discriminant_Use --
363 ----------------------------
371 begin
372 -- Any use in a default expression is legal.
379 -- Discriminant cannot be used to constrain a scalar type.
386 then
391 -- The following check catches the unusual case where
392 -- a discriminant appears within an index constraint
393 -- that is part of a larger expression within a constraint
394 -- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
395 -- For now we only check case of record components, and
396 -- note that a similar check should also apply in the
397 -- case of discriminant constraints below. ???
399 -- Note that the check for N_Subtype_Declaration below is to
400 -- detect the valid use of discriminants in the constraints of a
401 -- subtype declaration when this subtype declaration appears
402 -- inside the scope of a record type (which is syntactically
403 -- illegal, but which may be created as part of derived type
404 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
405 -- for more info.
409 and then not
411 and then
415 then
416 Error_Msg_N
421 -- Detect a common beginner error:
422 -- type R (D : Positive := 100) is record
423 -- Name: String (1 .. D);
424 -- end record;
426 -- The default value causes an object of type R to be
427 -- allocated with room for Positive'Last characters.
429 declare
436 -- Return True if type T has a large enough range that
437 -- any array whose index type covered the whole range of
438 -- the type would likely raise Storage_Error.
440 ------------------------
441 -- Large_Storage_Type --
442 ------------------------
445 begin
446 return
447 T = Standard_Integer
448 or else
449 T = Standard_Positive
450 or else
454 begin
455 -- Check that the Disc has a large range
461 -- If the enclosing type is limited, we allocate only the
462 -- default value, not the maximum, and there is no need for
463 -- a warning.
469 -- Check that it is the high bound
473 then
477 -- Check the array allows a large range at this bound.
478 -- First find the array
492 -- Next, find the dimension
500 loop
509 -- Now, check the dimension has a large range
515 -- Warn about the danger
517 Error_Msg_N
527 -- Legal case is in index or discriminant constraint
531 then
533 Error_Msg_N
539 -- Otherwise, context is an expression. It should not be within
540 -- (i.e. a subexpression of) a constraint for a component.
542 else
549 loop
555 -- If the discriminant is used in an expression that is a bound
556 -- of a scalar type, an Itype is created and the bounds are attached
557 -- to its range, not to the original subtype indication. Such use
558 -- is of course a double fault.
561 and then
563 or else
567 -- The constraint itself may be given by a subtype indication,
568 -- rather than by a more common discrete range.
571 and then
575 then
576 Error_Msg_N
582 --------------------------------
583 -- Check_For_Visible_Operator --
584 --------------------------------
587 begin
589 Error_Msg_NE
595 ------------------------------
596 -- Check_Infinite_Recursion --
597 ------------------------------
604 -- Check whether list of actuals is identical to list of formals
605 -- of called function (which is also the enclosing scope).
607 ------------------------
608 -- Same_Argument_List --
609 ------------------------
616 begin
619 else
629 then
640 -- Start of processing for Check_Infinite_Recursion
642 begin
643 -- Loop moving up tree, quitting if something tells us we are
644 -- definitely not in an infinite recursion situation.
647 loop
655 then
660 then
661 -- If the call is the expression of a return statement and
662 -- the actuals are identical to the formals, it's worth a
663 -- warning. However, we skip this if there is an immediately
664 -- preceding raise statement, since the call is never executed.
666 -- Furthermore, this corresponds to a common idiom:
668 -- function F (L : Thing) return Boolean is
669 -- begin
670 -- raise Program_Error;
671 -- return F (L);
672 -- end F;
674 -- for generating a stub function
677 and then Same_Argument_List
678 then
681 and then
683 or else
689 else
700 -------------------------------
701 -- Check_Initialization_Call --
702 -------------------------------
708 -- Check whether the creation of an object of the type will involve
709 -- use of the secondary stack. If T is a record type, this is true
710 -- if the expression for some component uses the secondary stack, eg.
711 -- through a call to a function that returns an unconstrained value.
712 -- False if T is controlled, because cleanups occur elsewhere.
714 -------------
715 -- Uses_SS --
716 -------------
722 begin
736 then
739 -- The expression for a dynamic component may be
740 -- rewritten as a dereference. Retrieve original
741 -- call.
745 then
758 else
763 -- Start of processing for Check_Initialization_Call
765 begin
766 -- Nothing to do if functions do not use the secondary stack for
767 -- returns (i.e. they use a depressed stack pointer instead).
772 -- Otherwise establish a transient scope if the type needs it
779 ------------------------------
780 -- Check_Parameterless_Call --
781 ------------------------------
786 begin
787 -- Defend against junk stuff if errors already detected
794 then
801 -- Rewrite as call if overloadable entity that is (or could be, in
802 -- the overloaded case) a function call. If we know for sure that
803 -- the entity is an enumeration literal, we do not rewrite it.
810 -- Rewrite as call if it is an explicit deference of an expression of
811 -- a subprogram access type, and the suprogram type is not that of a
812 -- procedure or entry.
814 or else
819 -- Rewrite as call if it is a selected component which is a function,
820 -- this is the case of a call to a protected function (which may be
821 -- overloaded with other protected operations).
823 or else
826 or else
828 or else
832 -- If one of the above three conditions is met, rewrite as call.
833 -- Apply the rewriting only once.
835 then
838 then
841 -- If overloaded, overload set belongs to new copy.
845 -- Change node to parameterless function call (note that the
846 -- Parameter_Associations associations field is left set to Empty,
847 -- its normal default value since there are no parameters)
860 ----------------------
861 -- Is_Predefined_Op --
862 ----------------------
865 begin
873 -----------------------------
874 -- Make_Call_Into_Operator --
875 -----------------------------
877 procedure Make_Call_Into_Operator
881 is
895 -- Determine whether E is an access type declared by an access decla-
896 -- ration, and not an (anonymous) allocator type.
899 -- If the operand is not universal, and the operator is given by a
900 -- expanded name, verify that the operand has an interpretation with
901 -- a type defined in the given scope of the operator.
904 -- Find a type of the given class in the package Pack that contains
905 -- the operator.
907 -----------------------------
908 -- Is_Definite_Access_Type --
909 -----------------------------
913 begin
919 ---------------------------
920 -- Operand_Type_In_Scope --
921 ---------------------------
928 begin
932 else
948 ---------------
949 -- Type_In_P --
950 ---------------
956 -- Verify that node is not part of the type declaration for the
957 -- candidate type, which would otherwise be invisible.
959 -------------
960 -- In_Decl --
961 -------------
967 begin
976 else
979 loop
982 else
991 -- Start of processing for Type_In_P
993 begin
994 -- If the context type is declared in the prefix package, this
995 -- is the desired base type.
999 then
1002 else
1008 and then not In_Decl
1009 then
1020 -- Start of processing for Make_Call_Into_Operator
1022 begin
1025 -- Binary operator
1035 -- Unary operator
1037 else
1043 -- If the operator is denoted by an expanded name, and the prefix is
1044 -- not Standard, but the operator is a predefined one whose scope is
1045 -- Standard, then this is an implicit_operator, inserted as an
1046 -- interpretation by the procedure of the same name. This procedure
1047 -- overestimates the presence of implicit operators, because it does
1048 -- not examine the type of the operands. Verify now that the operand
1049 -- type appears in the given scope. If right operand is universal,
1050 -- check the other operand. In the case of concatenation, either
1051 -- argument can be the component type, so check the type of the result.
1052 -- If both arguments are literals, look for a type of the right kind
1053 -- defined in the given scope. This elaborate nonsense is brought to
1054 -- you courtesy of b33302a. The type itself must be frozen, so we must
1055 -- find the type of the proper class in the given scope.
1057 -- A final wrinkle is the multiplication operator for fixed point
1058 -- types, which is defined in Standard only, and not in the scope of
1059 -- the fixed_point type itself.
1064 -- If the entity being called is defined in the given package,
1065 -- it is a renaming of a predefined operator, and known to be
1066 -- legal.
1070 then
1077 then
1082 else
1091 and then Is_Binary
1093 then
1099 -- Verify that the scope contains a type that corresponds to
1100 -- the given literal. Optimize the case where Pack is Standard.
1122 else
1131 else
1140 then
1143 -- If the type is defined elsewhere, and the operator is not
1144 -- defined in the given scope (by a renaming declaration, e.g.)
1145 -- then this is an error as well. If an extension of System is
1146 -- present, and the type may be defined there, Pack must be
1147 -- System itself.
1154 then
1159 then
1166 Error_Msg_NE
1177 else
1185 -- If this is an arithmetic operator and the result type is private,
1186 -- the operands and the result must be wrapped in conversion to
1187 -- expose the underlying numeric type and expand the proper checks,
1188 -- e.g. on division.
1192 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1193 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1202 else
1206 -- For predefined operators on literals, the operation freezes
1207 -- their type.
1215 -------------------
1216 -- Operator_Kind --
1217 -------------------
1219 function Operator_Kind
1222 return Node_Kind
1223 is
1226 begin
1245 else
1249 -- Unary operators
1251 else
1256 else
1264 -----------------------------
1265 -- Pre_Analyze_And_Resolve --
1266 -----------------------------
1271 begin
1275 -- We suppress all checks for this analysis, since the checks will
1276 -- be applied properly, and in the right location, when the default
1277 -- expression is reanalyzed and reexpanded later on.
1281 Expander_Mode_Restore;
1285 -- Version without context type.
1290 begin
1297 Expander_Mode_Restore;
1301 ----------------------------------
1302 -- Replace_Actual_Discriminants --
1303 ----------------------------------
1311 -------------------
1312 -- Process_Discr --
1313 -------------------
1318 begin
1324 then
1340 -- Start of processing for Replace_Actual_Discriminants
1342 begin
1356 else
1361 -------------
1362 -- Resolve --
1363 -------------
1378 -- Try and fix up a literal so that it matches its expected type. New
1379 -- literals are manufactured if necessary to avoid cascaded errors.
1382 -- Called when attempt at resolving current expression fails
1384 --------------------
1385 -- Patch_Up_Value --
1386 --------------------
1389 begin
1392 then
1401 then
1409 then
1420 then
1431 -----------------------
1432 -- Resolution_Failed --
1433 -----------------------
1436 begin
1442 -- The caller will return without calling the expander, so we need
1443 -- to set the analyzed flag. Note that it is fine to set Analyzed
1444 -- to True even if we are in the middle of a shallow analysis,
1445 -- (see the spec of sem for more details) since this is an error
1446 -- situation anyway, and there is no point in repeating the
1447 -- analysis later (indeed it won't work to repeat it later, since
1448 -- we haven't got a clear resolution of which entity is being
1449 -- referenced.)
1455 -- Start of processing for Resolve
1457 begin
1462 -- Access attribute on remote subprogram cannot be used for
1463 -- a non-remote access-to-subprogram type.
1474 then
1475 Error_Msg_N
1479 -- If the context is a Remote_Access_To_Subprogram, access attributes
1480 -- must be resolved with the corresponding fat pointer. There is no need
1481 -- to check for the attribute name since the return type of an
1482 -- attribute is never a remote type.
1488 then
1489 declare
1497 begin
1498 -- Check that Typ is a fat pointer with a reference to a RAS as
1499 -- original access type.
1501 if
1504 or else
1508 then
1509 -- Prefix (N) must statically denote a remote subprogram
1510 -- declared in a package specification.
1527 or else
1529 then
1531 Error_Msg_N
1533 N);
1537 -- If we are generating code for a distributed program.
1538 -- perform semantic checks against the corresponding
1539 -- remote entities.
1544 and then Expander_Active
1545 then
1546 Check_Subtype_Conformant
1548 Old_Id => Designated_Type
1568 then
1573 -- Return if already analyzed
1579 -- Return if type = Any_Type (previous error encountered)
1588 -- If not overloaded, then we know the type, and all that needs doing
1589 -- is to check that this type is compatible with the context.
1595 -- In the overloaded case, we must select the interpretation that
1596 -- is compatible with the context (i.e. the type passed to Resolve)
1598 else
1601 -- Loop through possible interpretations
1605 -- We are only interested in interpretations that are compatible
1606 -- with the expected type, any other interpretations are ignored
1611 Write_Eol;
1614 else
1615 -- First matching interpretation
1623 -- Matching interpretation that is not the first, maybe an
1624 -- error, but there are some cases where preference rules are
1625 -- used to choose between the two possibilities. These and
1626 -- some more obscure cases are handled in Disambiguate.
1628 else
1632 -- Disambiguation has succeeded. Skip the remaining
1633 -- interpretations.
1643 else
1644 -- Before we issue an ambiguity complaint, check for
1645 -- the case of a subprogram call where at least one
1646 -- of the arguments is Any_Type, and if so, suppress
1647 -- the message, since it is a cascaded error.
1651 then
1652 declare
1656 begin
1667 Write_Eol;
1680 then
1685 then
1689 -- Not that special case, so issue message using the
1690 -- flag Ambiguous to control printing of the header
1691 -- message only at the start of an ambiguous set.
1694 Error_Msg_NE
1698 Error_Msg_N
1705 -- By default, the error message refers to the candidate
1706 -- interpretation. But if it is a predefined operator,
1707 -- it is implicitly declared at the declaration of
1708 -- the type of the operand. Recover the sloc of that
1709 -- declaration for the error message.
1715 /= Standard_Standard
1716 then
1721 then
1729 /= Standard_Standard
1730 then
1735 then
1738 else
1745 then
1746 Error_Msg_N
1748 else
1755 -- We have a matching interpretation, Expr_Type is the
1756 -- type from this interpretation, and Seen is the entity.
1758 -- For an operator, just set the entity name. The type will
1759 -- be set by the specific operator resolution routine.
1768 -- For an explicit dereference, attribute reference, range,
1769 -- short-circuit form (which is not an operator node),
1770 -- or a call with a name that is an explicit dereference,
1771 -- there is nothing to be done at this point.
1782 then
1785 -- For procedure or function calls, set the type of the
1786 -- name, and also the entity pointer for the prefix
1792 then
1799 then
1804 -- For all other cases, just set the type of the Name
1806 else
1812 -- Move to next interpretation
1820 -- At this stage Found indicates whether or not an acceptable
1821 -- interpretation exists. If not, then we have an error, except
1822 -- that if the context is Any_Type as a result of some other error,
1823 -- then we suppress the error report.
1828 -- If type we are looking for is Void, then this is the
1829 -- procedure call case, and the error is simply that what
1830 -- we gave is not a procedure name (we think of procedure
1831 -- calls as expressions with types internally, but the user
1832 -- doesn't think of them this way!)
1838 -- Otherwise we do have a subexpression with the wrong type
1840 -- Check for the case of an allocator which uses an access
1841 -- type instead of the designated type. This is a common
1842 -- error and we specialize the message, posting an error
1843 -- on the operand of the allocator, complaining that we
1844 -- expected the designated type of the allocator.
1850 then
1854 -- Check for view mismatch on Null in instances, for
1855 -- which the view-swapping mechanism has no identifier.
1861 then
1866 -- Check for an aggregate. Sometimes we can get bogus
1867 -- aggregates from misuse of parentheses, and we are
1868 -- about to complain about the aggregate without even
1869 -- looking inside it.
1871 -- Instead, if we have an aggregate of type Any_Composite,
1872 -- then analyze and resolve the component fields, and then
1873 -- only issue another message if we get no errors doing
1874 -- this (otherwise assume that the errors in the aggregate
1875 -- caused the problem).
1879 then
1880 -- Disable expansion in any case. If there is a type mismatch
1881 -- it may be fatal to try to expand the aggregate. The flag
1882 -- would otherwise be set to false when the error is posted.
1886 declare
1888 -- Check one aggregate, and set Found to True if we
1889 -- have a definite error in any of its elements
1892 -- Check one element of aggregate and set Found to
1893 -- True if we definitely have an error in the element.
1898 begin
1916 ----------------
1917 -- Check_Elmt --
1918 ----------------
1921 begin
1922 -- If we have a nested aggregate, go inside it (to
1923 -- attempt a naked analyze-resolve of the aggregate
1924 -- can cause undesirable cascaded errors). Do not
1925 -- resolve expression if it needs a type from context,
1926 -- as for integer * fixed expression.
1931 else
1936 then
1946 begin
1951 -- If an error message was issued already, Found got reset
1952 -- to True, so if it is still False, issue the standard
1953 -- Wrong_Type message.
1958 then
1959 declare
1961 begin
1967 -- Protected operation: retrieve operation name.
1970 else
1980 declare
1984 begin
1998 else
2001 else
2007 Resolution_Failed;
2010 -- Test if we have more than one interpretation for the context
2013 Resolution_Failed;
2016 -- Here we have an acceptable interpretation for the context
2018 else
2019 -- A user-defined operator is tranformed into a function call at
2020 -- this point, so that further processing knows that operators are
2021 -- really operators (i.e. are predefined operators). User-defined
2022 -- operators that are intrinsic are just renamings of the predefined
2023 -- ones, and need not be turned into calls either, but if they rename
2024 -- a different operator, we must transform the node accordingly.
2025 -- Instantiations of Unchecked_Conversion are intrinsic but are
2026 -- treated as functions, even if given an operator designator.
2031 then
2041 -- Propagate type information and normalize tree for various
2042 -- predefined operations. If the context only imposes a class of
2043 -- types, rather than a specific type, propagate the actual type
2044 -- downward.
2051 then
2054 -- Any_Fixed is legal in a real context only if a specific
2055 -- fixed point type is imposed. If Norman Cohen can be
2056 -- confused by this, it deserves a separate message.
2060 then
2069 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2071 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2073 when N_And_Then | N_Or_Else
2074 => Resolve_Short_Circuit (N, Ctx_Type);
2076 when N_Attribute_Reference
2077 => Resolve_Attribute (N, Ctx_Type);
2079 when N_Character_Literal
2080 => Resolve_Character_Literal (N, Ctx_Type);
2082 when N_Conditional_Expression
2083 => Resolve_Conditional_Expression (N, Ctx_Type);
2085 when N_Expanded_Name
2086 => Resolve_Entity_Name (N, Ctx_Type);
2088 when N_Extension_Aggregate
2089 => Resolve_Extension_Aggregate (N, Ctx_Type);
2091 when N_Explicit_Dereference
2092 => Resolve_Explicit_Dereference (N, Ctx_Type);
2094 when N_Function_Call
2095 => Resolve_Call (N, Ctx_Type);
2097 when N_Identifier
2098 => Resolve_Entity_Name (N, Ctx_Type);
2100 when N_In | N_Not_In
2101 => Resolve_Membership_Op (N, Ctx_Type);
2103 when N_Indexed_Component
2104 => Resolve_Indexed_Component (N, Ctx_Type);
2106 when N_Integer_Literal
2107 => Resolve_Integer_Literal (N, Ctx_Type);
2109 when N_Null => Resolve_Null (N, Ctx_Type);
2111 when N_Op_And | N_Op_Or | N_Op_Xor
2112 => Resolve_Logical_Op (N, Ctx_Type);
2114 when N_Op_Eq | N_Op_Ne
2115 => Resolve_Equality_Op (N, Ctx_Type);
2117 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2118 => Resolve_Comparison_Op (N, Ctx_Type);
2120 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2122 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2123 N_Op_Divide | N_Op_Mod | N_Op_Rem
2125 => Resolve_Arithmetic_Op (N, Ctx_Type);
2127 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2129 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2131 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2132 => Resolve_Unary_Op (N, Ctx_Type);
2134 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2136 when N_Procedure_Call_Statement
2137 => Resolve_Call (N, Ctx_Type);
2139 when N_Operator_Symbol
2140 => Resolve_Operator_Symbol (N, Ctx_Type);
2142 when N_Qualified_Expression
2143 => Resolve_Qualified_Expression (N, Ctx_Type);
2145 when N_Raise_xxx_Error
2146 => Set_Etype (N, Ctx_Type);
2148 when N_Range => Resolve_Range (N, Ctx_Type);
2150 when N_Real_Literal
2151 => Resolve_Real_Literal (N, Ctx_Type);
2153 when N_Reference => Resolve_Reference (N, Ctx_Type);
2155 when N_Selected_Component
2156 => Resolve_Selected_Component (N, Ctx_Type);
2158 when N_Slice => Resolve_Slice (N, Ctx_Type);
2160 when N_String_Literal
2161 => Resolve_String_Literal (N, Ctx_Type);
2163 when N_Subprogram_Info
2164 => Resolve_Subprogram_Info (N, Ctx_Type);
2166 when N_Type_Conversion
2167 => Resolve_Type_Conversion (N, Ctx_Type);
2169 when N_Unchecked_Expression =>
2170 Resolve_Unchecked_Expression (N, Ctx_Type);
2172 when N_Unchecked_Type_Conversion =>
2173 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2175 end case;
2177 -- If the subexpression was replaced by a non-subexpression, then
2178 -- all we do is to expand it. The only legitimate case we know of
2179 -- is converting procedure call statement to entry call statements,
2180 -- but there may be others, so we are making this test general.
2182 if Nkind (N) not in N_Subexpr then
2183 Debug_A_Exit ("resolving ", N, " (done)");
2184 Expand (N);
2185 return;
2186 end if;
2188 -- The expression is definitely NOT overloaded at this point, so
2189 -- we reset the Is_Overloaded flag to avoid any confusion when
2190 -- reanalyzing the node.
2192 Set_Is_Overloaded (N, False);
2194 -- Freeze expression type, entity if it is a name, and designated
2195 -- type if it is an allocator (RM 13.14(10,11,13)).
2197 -- Now that the resolution of the type of the node is complete,
2198 -- and we did not detect an error, we can expand this node. We
2199 -- skip the expand call if we are in a default expression, see
2200 -- section "Handling of Default Expressions" in Sem spec.
2202 Debug_A_Exit ("resolving ", N, " (done)");
2204 -- We unconditionally freeze the expression, even if we are in
2205 -- default expression mode (the Freeze_Expression routine tests
2206 -- this flag and only freezes static types if it is set).
2208 Freeze_Expression (N);
2210 -- Now we can do the expansion
2212 Expand (N);
2213 end if;
2214 end Resolve;
2216 -------------
2217 -- Resolve --
2218 -------------
2220 -- Version with check(s) suppressed
2222 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2223 begin
2224 if Suppress = All_Checks then
2225 declare
2226 Svg : constant Suppress_Array := Scope_Suppress;
2228 begin
2229 Scope_Suppress := (others => True);
2230 Resolve (N, Typ);
2231 Scope_Suppress := Svg;
2232 end;
2234 else
2235 declare
2236 Svg : constant Boolean := Scope_Suppress (Suppress);
2238 begin
2239 Scope_Suppress (Suppress) := True;
2240 Resolve (N, Typ);
2241 Scope_Suppress (Suppress) := Svg;
2242 end;
2243 end if;
2244 end Resolve;
2246 -------------
2247 -- Resolve --
2248 -------------
2250 -- Version with implicit type
2252 procedure Resolve (N : Node_Id) is
2253 begin
2254 Resolve (N, Etype (N));
2255 end Resolve;
2257 ---------------------
2258 -- Resolve_Actuals --
2259 ---------------------
2261 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2262 Loc : constant Source_Ptr := Sloc (N);
2263 A : Node_Id;
2264 F : Entity_Id;
2265 A_Typ : Entity_Id;
2266 F_Typ : Entity_Id;
2267 Prev : Node_Id := Empty;
2269 procedure Insert_Default;
2270 -- If the actual is missing in a call, insert in the actuals list
2271 -- an instance of the default expression. The insertion is always
2272 -- a named association.
2274 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean;
2275 -- Check whether T1 and T2, or their full views, are derived from a
2276 -- common type. Used to enforce the restrictions on array conversions
2277 -- of AI95-00246.
2279 --------------------
2280 -- Insert_Default --
2281 --------------------
2283 procedure Insert_Default is
2284 Actval : Node_Id;
2285 Assoc : Node_Id;
2287 begin
2288 -- Missing argument in call, nothing to insert
2290 if No (Default_Value (F)) then
2291 return;
2293 else
2294 -- Note that we do a full New_Copy_Tree, so that any associated
2295 -- Itypes are properly copied. This may not be needed any more,
2296 -- but it does no harm as a safety measure! Defaults of a generic
2297 -- formal may be out of bounds of the corresponding actual (see
2298 -- cc1311b) and an additional check may be required.
2300 Actval := New_Copy_Tree (Default_Value (F),
2301 New_Scope => Current_Scope, New_Sloc => Loc);
2303 if Is_Concurrent_Type (Scope (Nam))
2304 and then Has_Discriminants (Scope (Nam))
2305 then
2306 Replace_Actual_Discriminants (N, Actval);
2307 end if;
2309 if Is_Overloadable (Nam)
2310 and then Present (Alias (Nam))
2311 then
2312 if Base_Type (Etype (F)) /= Base_Type (Etype (Actval))
2313 and then not Is_Tagged_Type (Etype (F))
2314 then
2315 -- If default is a real literal, do not introduce a
2316 -- conversion whose effect may depend on the run-time
2317 -- size of universal real.
2319 if Nkind (Actval) = N_Real_Literal then
2320 Set_Etype (Actval, Base_Type (Etype (F)));
2321 else
2322 Actval := Unchecked_Convert_To (Etype (F), Actval);
2323 end if;
2324 end if;
2326 if Is_Scalar_Type (Etype (F)) then
2327 Enable_Range_Check (Actval);
2328 end if;
2330 Set_Parent (Actval, N);
2332 -- Resolve aggregates with their base type, to avoid scope
2333 -- anomalies: the subtype was first built in the suprogram
2334 -- declaration, and the current call may be nested.
2336 if Nkind (Actval) = N_Aggregate
2337 and then Has_Discriminants (Etype (Actval))
2338 then
2339 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
2340 else
2341 Analyze_And_Resolve (Actval, Etype (Actval));
2342 end if;
2344 else
2345 Set_Parent (Actval, N);
2347 -- See note above concerning aggregates.
2349 if Nkind (Actval) = N_Aggregate
2350 and then Has_Discriminants (Etype (Actval))
2351 then
2352 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
2354 -- Resolve entities with their own type, which may differ
2355 -- from the type of a reference in a generic context (the
2356 -- view swapping mechanism did not anticipate the re-analysis
2357 -- of default values in calls).
2359 elsif Is_Entity_Name (Actval) then
2360 Analyze_And_Resolve (Actval, Etype (Entity (Actval)));
2362 else
2363 Analyze_And_Resolve (Actval, Etype (Actval));
2364 end if;
2365 end if;
2367 -- If default is a tag indeterminate function call, propagate
2368 -- tag to obtain proper dispatching.
2370 if Is_Controlling_Formal (F)
2371 and then Nkind (Default_Value (F)) = N_Function_Call
2372 then
2373 Set_Is_Controlling_Actual (Actval);
2374 end if;
2376 end if;
2378 -- If the default expression raises constraint error, then just
2379 -- silently replace it with an N_Raise_Constraint_Error node,
2380 -- since we already gave the warning on the subprogram spec.
2382 if Raises_Constraint_Error (Actval) then
2383 Rewrite (Actval,
2384 Make_Raise_Constraint_Error (Loc,
2385 Reason => CE_Range_Check_Failed));
2386 Set_Raises_Constraint_Error (Actval);
2387 Set_Etype (Actval, Etype (F));
2388 end if;
2390 Assoc :=
2391 Make_Parameter_Association (Loc,
2392 Explicit_Actual_Parameter => Actval,
2393 Selector_Name => Make_Identifier (Loc, Chars (F)));
2395 -- Case of insertion is first named actual
2397 if No (Prev) or else
2398 Nkind (Parent (Prev)) /= N_Parameter_Association
2399 then
2400 Set_Next_Named_Actual (Assoc, First_Named_Actual (N));
2401 Set_First_Named_Actual (N, Actval);
2403 if No (Prev) then
2404 if not Present (Parameter_Associations (N)) then
2405 Set_Parameter_Associations (N, New_List (Assoc));
2406 else
2407 Append (Assoc, Parameter_Associations (N));
2408 end if;
2410 else
2411 Insert_After (Prev, Assoc);
2412 end if;
2414 -- Case of insertion is not first named actual
2416 else
2417 Set_Next_Named_Actual
2418 (Assoc, Next_Named_Actual (Parent (Prev)));
2419 Set_Next_Named_Actual (Parent (Prev), Actval);
2420 Append (Assoc, Parameter_Associations (N));
2421 end if;
2423 Mark_Rewrite_Insertion (Assoc);
2424 Mark_Rewrite_Insertion (Actval);
2426 Prev := Actval;
2427 end Insert_Default;
2429 -------------------
2430 -- Same_Ancestor --
2431 -------------------
2433 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean is
2434 FT1 : Entity_Id := T1;
2435 FT2 : Entity_Id := T2;
2437 begin
2438 if Is_Private_Type (T1)
2439 and then Present (Full_View (T1))
2440 then
2441 FT1 := Full_View (T1);
2442 end if;
2444 if Is_Private_Type (T2)
2445 and then Present (Full_View (T2))
2446 then
2447 FT2 := Full_View (T2);
2448 end if;
2450 return Root_Type (Base_Type (FT1)) = Root_Type (Base_Type (FT2));
2451 end Same_Ancestor;
2453 -- Start of processing for Resolve_Actuals
2455 begin
2456 A := First_Actual (N);
2457 F := First_Formal (Nam);
2459 while Present (F) loop
2460 if No (A) and then Needs_No_Actuals (Nam) then
2461 null;
2463 -- If we have an error in any actual or formal, indicated by
2464 -- a type of Any_Type, then abandon resolution attempt, and
2465 -- set result type to Any_Type.
2467 elsif (Present (A) and then Etype (A) = Any_Type)
2468 or else Etype (F) = Any_Type
2469 then
2470 Set_Etype (N, Any_Type);
2471 return;
2472 end if;
2474 if Present (A)
2475 and then (Nkind (Parent (A)) /= N_Parameter_Association
2476 or else
2477 Chars (Selector_Name (Parent (A))) = Chars (F))
2478 then
2479 -- If the formal is Out or In_Out, do not resolve and expand the
2480 -- conversion, because it is subsequently expanded into explicit
2481 -- temporaries and assignments. However, the object of the
2482 -- conversion can be resolved. An exception is the case of
2483 -- a tagged type conversion with a class-wide actual. In that
2484 -- case we want the tag check to occur and no temporary will
2485 -- will be needed (no representation change can occur) and
2486 -- the parameter is passed by reference, so we go ahead and
2487 -- resolve the type conversion.
2489 if Ekind (F) /= E_In_Parameter
2490 and then Nkind (A) = N_Type_Conversion
2491 and then not Is_Class_Wide_Type (Etype (Expression (A)))
2492 then
2493 if Ekind (F) = E_In_Out_Parameter
2494 and then Is_Array_Type (Etype (F))
2495 then
2496 if Has_Aliased_Components (Etype (Expression (A)))
2497 /= Has_Aliased_Components (Etype (F))
2498 then
2499 Error_Msg_N
2500 ("both component types in a view conversion must be"
2501 & " aliased, or neither", A);
2503 elsif not Same_Ancestor (Etype (F), Etype (Expression (A)))
2504 and then
2505 (Is_By_Reference_Type (Etype (F))
2506 or else Is_By_Reference_Type (Etype (Expression (A))))
2507 then
2508 Error_Msg_N
2509 ("view conversion between unrelated by_reference "
2511 end if;
2512 end if;
2514 if Conversion_OK (A)
2515 or else Valid_Conversion (A, Etype (A), Expression (A))
2516 then
2517 Resolve (Expression (A));
2518 end if;
2520 else
2521 if Nkind (A) = N_Type_Conversion
2522 and then Is_Array_Type (Etype (F))
2523 and then not Same_Ancestor (Etype (F), Etype (Expression (A)))
2524 and then
2525 (Is_Limited_Type (Etype (F))
2526 or else Is_Limited_Type (Etype (Expression (A))))
2527 then
2528 Error_Msg_N
2529 ("Conversion between unrelated limited array types "
2532 -- Disable explanation (which produces additional errors)
2533 -- until AI is approved and warning becomes an error.
2535 -- if Is_Limited_Type (Etype (F)) then
2536 -- Explain_Limited_Type (Etype (F), A);
2537 -- end if;
2539 -- if Is_Limited_Type (Etype (Expression (A))) then
2540 -- Explain_Limited_Type (Etype (Expression (A)), A);
2541 -- end if;
2542 end if;
2544 Resolve (A, Etype (F));
2545 end if;
2547 A_Typ := Etype (A);
2548 F_Typ := Etype (F);
2550 -- Perform error checks for IN and IN OUT parameters
2552 if Ekind (F) /= E_Out_Parameter then
2554 -- Check unset reference. For scalar parameters, it is clearly
2555 -- wrong to pass an uninitialized value as either an IN or
2556 -- IN-OUT parameter. For composites, it is also clearly an
2557 -- error to pass a completely uninitialized value as an IN
2558 -- parameter, but the case of IN OUT is trickier. We prefer
2559 -- not to give a warning here. For example, suppose there is
2560 -- a routine that sets some component of a record to False.
2561 -- It is perfectly reasonable to make this IN-OUT and allow
2562 -- either initialized or uninitialized records to be passed
2563 -- in this case.
2565 -- For partially initialized composite values, we also avoid
2566 -- warnings, since it is quite likely that we are passing a
2567 -- partially initialized value and only the initialized fields
2568 -- will in fact be read in the subprogram.
2570 if Is_Scalar_Type (A_Typ)
2571 or else (Ekind (F) = E_In_Parameter
2572 and then not Is_Partially_Initialized_Type (A_Typ))
2573 then
2574 Check_Unset_Reference (A);
2575 end if;
2577 -- In Ada 83 we cannot pass an OUT parameter as an IN
2578 -- or IN OUT actual to a nested call, since this is a
2579 -- case of reading an out parameter, which is not allowed.
2581 if Ada_83
2582 and then Is_Entity_Name (A)
2583 and then Ekind (Entity (A)) = E_Out_Parameter
2584 then
2585 Error_Msg_N ("(Ada 83) illegal reading of out parameter", A);
2586 end if;
2587 end if;
2589 if Ekind (F) /= E_In_Parameter
2590 and then not Is_OK_Variable_For_Out_Formal (A)
2591 then
2592 Error_Msg_NE ("actual for& must be a variable", A, F);
2594 if Is_Entity_Name (A) then
2595 Kill_Checks (Entity (A));
2596 else
2597 Kill_All_Checks;
2598 end if;
2599 end if;
2601 if Etype (A) = Any_Type then
2602 Set_Etype (N, Any_Type);
2603 return;
2604 end if;
2606 -- Apply appropriate range checks for in, out, and in-out
2607 -- parameters. Out and in-out parameters also need a separate
2608 -- check, if there is a type conversion, to make sure the return
2609 -- value meets the constraints of the variable before the
2610 -- conversion.
2612 -- Gigi looks at the check flag and uses the appropriate types.
2613 -- For now since one flag is used there is an optimization which
2614 -- might not be done in the In Out case since Gigi does not do
2615 -- any analysis. More thought required about this ???
2617 if Ekind (F) = E_In_Parameter
2618 or else Ekind (F) = E_In_Out_Parameter
2619 then
2620 if Is_Scalar_Type (Etype (A)) then
2621 Apply_Scalar_Range_Check (A, F_Typ);
2623 elsif Is_Array_Type (Etype (A)) then
2624 Apply_Length_Check (A, F_Typ);
2626 elsif Is_Record_Type (F_Typ)
2627 and then Has_Discriminants (F_Typ)
2628 and then Is_Constrained (F_Typ)
2629 and then (not Is_Derived_Type (F_Typ)
2630 or else Comes_From_Source (Nam))
2631 then
2632 Apply_Discriminant_Check (A, F_Typ);
2634 elsif Is_Access_Type (F_Typ)
2635 and then Is_Array_Type (Designated_Type (F_Typ))
2636 and then Is_Constrained (Designated_Type (F_Typ))
2637 then
2638 Apply_Length_Check (A, F_Typ);
2640 elsif Is_Access_Type (F_Typ)
2641 and then Has_Discriminants (Designated_Type (F_Typ))
2642 and then Is_Constrained (Designated_Type (F_Typ))
2643 then
2644 Apply_Discriminant_Check (A, F_Typ);
2646 else
2647 Apply_Range_Check (A, F_Typ);
2648 end if;
2649 end if;
2651 if Ekind (F) = E_Out_Parameter
2652 or else Ekind (F) = E_In_Out_Parameter
2653 then
2654 if Nkind (A) = N_Type_Conversion then
2655 if Is_Scalar_Type (A_Typ) then
2656 Apply_Scalar_Range_Check
2657 (Expression (A), Etype (Expression (A)), A_Typ);
2658 else
2659 Apply_Range_Check
2660 (Expression (A), Etype (Expression (A)), A_Typ);
2661 end if;
2663 else
2664 if Is_Scalar_Type (F_Typ) then
2665 Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
2667 elsif Is_Array_Type (F_Typ)
2668 and then Ekind (F) = E_Out_Parameter
2669 then
2670 Apply_Length_Check (A, F_Typ);
2672 else
2673 Apply_Range_Check (A, A_Typ, F_Typ);
2674 end if;
2675 end if;
2676 end if;
2678 -- An actual associated with an access parameter is implicitly
2679 -- converted to the anonymous access type of the formal and
2680 -- must satisfy the legality checks for access conversions.
2682 if Ekind (F_Typ) = E_Anonymous_Access_Type then
2683 if not Valid_Conversion (A, F_Typ, A) then
2684 Error_Msg_N
2685 ("invalid implicit conversion for access parameter", A);
2686 end if;
2687 end if;
2689 -- Check bad case of atomic/volatile argument (RM C.6(12))
2691 if Is_By_Reference_Type (Etype (F))
2692 and then Comes_From_Source (N)
2693 then
2694 if Is_Atomic_Object (A)
2695 and then not Is_Atomic (Etype (F))
2696 then
2697 Error_Msg_N
2698 ("cannot pass atomic argument to non-atomic formal",
2699 N);
2701 elsif Is_Volatile_Object (A)
2702 and then not Is_Volatile (Etype (F))
2703 then
2704 Error_Msg_N
2705 ("cannot pass volatile argument to non-volatile formal",
2706 N);
2707 end if;
2708 end if;
2710 -- Check that subprograms don't have improper controlling
2711 -- arguments (RM 3.9.2 (9))
2713 if Is_Controlling_Formal (F) then
2714 Set_Is_Controlling_Actual (A);
2715 elsif Nkind (A) = N_Explicit_Dereference then
2716 Validate_Remote_Access_To_Class_Wide_Type (A);
2717 end if;
2719 if (Is_Class_Wide_Type (A_Typ) or else Is_Dynamically_Tagged (A))
2720 and then not Is_Class_Wide_Type (F_Typ)
2721 and then not Is_Controlling_Formal (F)
2722 then
2723 Error_Msg_N ("class-wide argument not allowed here!", A);
2725 if Is_Subprogram (Nam)
2726 and then Comes_From_Source (Nam)
2727 then
2728 Error_Msg_Node_2 := F_Typ;
2729 Error_Msg_NE
2730 ("& is not a primitive operation of &!", A, Nam);
2731 end if;
2733 elsif Is_Access_Type (A_Typ)
2734 and then Is_Access_Type (F_Typ)
2735 and then Ekind (F_Typ) /= E_Access_Subprogram_Type
2736 and then (Is_Class_Wide_Type (Designated_Type (A_Typ))
2737 or else (Nkind (A) = N_Attribute_Reference
2738 and then
2739 Is_Class_Wide_Type (Etype (Prefix (A)))))
2740 and then not Is_Class_Wide_Type (Designated_Type (F_Typ))
2741 and then not Is_Controlling_Formal (F)
2742 then
2743 Error_Msg_N
2744 ("access to class-wide argument not allowed here!", A);
2746 if Is_Subprogram (Nam)
2747 and then Comes_From_Source (Nam)
2748 then
2749 Error_Msg_Node_2 := Designated_Type (F_Typ);
2750 Error_Msg_NE
2751 ("& is not a primitive operation of &!", A, Nam);
2752 end if;
2753 end if;
2755 Eval_Actual (A);
2757 -- If it is a named association, treat the selector_name as
2758 -- a proper identifier, and mark the corresponding entity.
2760 if Nkind (Parent (A)) = N_Parameter_Association then
2761 Set_Entity (Selector_Name (Parent (A)), F);
2762 Generate_Reference (F, Selector_Name (Parent (A)));
2763 Set_Etype (Selector_Name (Parent (A)), F_Typ);
2765 end if;
2767 Prev := A;
2769 if Ekind (F) /= E_Out_Parameter then
2770 Check_Unset_Reference (A);
2771 end if;
2773 Next_Actual (A);
2775 -- Case where actual is not present
2777 else
2778 Insert_Default;
2779 end if;
2781 Next_Formal (F);
2782 end loop;
2783 end Resolve_Actuals;
2785 -----------------------
2786 -- Resolve_Allocator --
2787 -----------------------
2789 procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id) is
2790 E : constant Node_Id := Expression (N);
2791 Subtyp : Entity_Id;
2792 Discrim : Entity_Id;
2793 Constr : Node_Id;
2794 Disc_Exp : Node_Id;
2796 function In_Dispatching_Context return Boolean;
2797 -- If the allocator is an actual in a call, it is allowed to be
2798 -- class-wide when the context is not because it is a controlling
2799 -- actual.
2801 ----------------------------
2802 -- In_Dispatching_Context --
2803 ----------------------------
2805 function In_Dispatching_Context return Boolean is
2806 Par : constant Node_Id := Parent (N);
2808 begin
2809 return (Nkind (Par) = N_Function_Call
2810 or else Nkind (Par) = N_Procedure_Call_Statement)
2811 and then Is_Entity_Name (Name (Par))
2812 and then Is_Dispatching_Operation (Entity (Name (Par)));
2813 end In_Dispatching_Context;
2815 -- Start of processing for Resolve_Allocator
2817 begin
2818 -- Replace general access with specific type
2820 if Ekind (Etype (N)) = E_Allocator_Type then
2821 Set_Etype (N, Base_Type (Typ));
2822 end if;
2824 if Is_Abstract (Typ) then
2825 Error_Msg_N ("type of allocator cannot be abstract", N);
2826 end if;
2828 -- For qualified expression, resolve the expression using the
2829 -- given subtype (nothing to do for type mark, subtype indication)
2831 if Nkind (E) = N_Qualified_Expression then
2832 if Is_Class_Wide_Type (Etype (E))
2833 and then not Is_Class_Wide_Type (Designated_Type (Typ))
2834 and then not In_Dispatching_Context
2835 then
2836 Error_Msg_N
2837 ("class-wide allocator not allowed for this access type", N);
2838 end if;
2840 Resolve (Expression (E), Etype (E));
2841 Check_Unset_Reference (Expression (E));
2843 -- A qualified expression requires an exact match of the type,
2844 -- class-wide matching is not allowed.
2846 if (Is_Class_Wide_Type (Etype (Expression (E)))
2847 or else Is_Class_Wide_Type (Etype (E)))
2848 and then Base_Type (Etype (Expression (E))) /= Base_Type (Etype (E))
2849 then
2850 Wrong_Type (Expression (E), Etype (E));
2851 end if;
2853 -- For a subtype mark or subtype indication, freeze the subtype
2855 else
2856 Freeze_Expression (E);
2858 if Is_Access_Constant (Typ) and then not No_Initialization (N) then
2859 Error_Msg_N
2860 ("initialization required for access-to-constant allocator", N);
2861 end if;
2863 -- A special accessibility check is needed for allocators that
2864 -- constrain access discriminants. The level of the type of the
2865 -- expression used to contrain an access discriminant cannot be
2866 -- deeper than the type of the allocator (in constrast to access
2867 -- parameters, where the level of the actual can be arbitrary).
2868 -- We can't use Valid_Conversion to perform this check because
2869 -- in general the type of the allocator is unrelated to the type
2870 -- of the access discriminant. Note that specialized checks are
2871 -- needed for the cases of a constraint expression which is an
2872 -- access attribute or an access discriminant.
2874 if Nkind (Original_Node (E)) = N_Subtype_Indication
2875 and then Ekind (Typ) /= E_Anonymous_Access_Type
2876 then
2877 Subtyp := Entity (Subtype_Mark (Original_Node (E)));
2879 if Has_Discriminants (Subtyp) then
2880 Discrim := First_Discriminant (Base_Type (Subtyp));
2881 Constr := First (Constraints (Constraint (Original_Node (E))));
2883 while Present (Discrim) and then Present (Constr) loop
2884 if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
2885 if Nkind (Constr) = N_Discriminant_Association then
2886 Disc_Exp := Original_Node (Expression (Constr));
2887 else
2888 Disc_Exp := Original_Node (Constr);
2889 end if;
2891 if Type_Access_Level (Etype (Disc_Exp))
2892 > Type_Access_Level (Typ)
2893 then
2894 Error_Msg_N
2895 ("operand type has deeper level than allocator type",
2896 Disc_Exp);
2898 elsif Nkind (Disc_Exp) = N_Attribute_Reference
2899 and then Get_Attribute_Id (Attribute_Name (Disc_Exp))
2900 = Attribute_Access
2901 and then Object_Access_Level (Prefix (Disc_Exp))
2902 > Type_Access_Level (Typ)
2903 then
2904 Error_Msg_N
2905 ("prefix of attribute has deeper level than"
2906 & " allocator type", Disc_Exp);
2908 -- When the operand is an access discriminant the check
2909 -- is against the level of the prefix object.
2911 elsif Ekind (Etype (Disc_Exp)) = E_Anonymous_Access_Type
2912 and then Nkind (Disc_Exp) = N_Selected_Component
2913 and then Object_Access_Level (Prefix (Disc_Exp))
2914 > Type_Access_Level (Typ)
2915 then
2916 Error_Msg_N
2917 ("access discriminant has deeper level than"
2918 & " allocator type", Disc_Exp);
2919 end if;
2920 end if;
2921 Next_Discriminant (Discrim);
2922 Next (Constr);
2923 end loop;
2924 end if;
2925 end if;
2926 end if;
2928 -- Check for allocation from an empty storage pool
2930 if No_Pool_Assigned (Typ) then
2931 declare
2932 Loc : constant Source_Ptr := Sloc (N);
2934 begin
2935 Error_Msg_N ("?allocation from empty storage pool!", N);
2936 Error_Msg_N ("?Storage_Error will be raised at run time!", N);
2937 Insert_Action (N,
2938 Make_Raise_Storage_Error (Loc,
2939 Reason => SE_Empty_Storage_Pool));
2940 end;
2941 end if;
2942 end Resolve_Allocator;
2944 ---------------------------
2945 -- Resolve_Arithmetic_Op --
2946 ---------------------------
2948 -- Used for resolving all arithmetic operators except exponentiation
2950 procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id) is
2951 L : constant Node_Id := Left_Opnd (N);
2952 R : constant Node_Id := Right_Opnd (N);
2953 TL : constant Entity_Id := Base_Type (Etype (L));
2954 TR : constant Entity_Id := Base_Type (Etype (R));
2955 T : Entity_Id;
2956 Rop : Node_Id;
2958 B_Typ : constant Entity_Id := Base_Type (Typ);
2959 -- We do the resolution using the base type, because intermediate values
2960 -- in expressions always are of the base type, not a subtype of it.
2962 function Is_Integer_Or_Universal (N : Node_Id) return Boolean;
2963 -- Return True iff given type is Integer or universal real/integer
2965 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id);
2966 -- Choose type of integer literal in fixed-point operation to conform
2967 -- to available fixed-point type. T is the type of the other operand,
2968 -- which is needed to determine the expected type of N.
2970 procedure Set_Operand_Type (N : Node_Id);
2971 -- Set operand type to T if universal
2973 -----------------------------
2974 -- Is_Integer_Or_Universal --
2975 -----------------------------
2977 function Is_Integer_Or_Universal (N : Node_Id) return Boolean is
2978 T : Entity_Id;
2979 Index : Interp_Index;
2980 It : Interp;
2982 begin
2983 if not Is_Overloaded (N) then
2984 T := Etype (N);
2985 return Base_Type (T) = Base_Type (Standard_Integer)
2986 or else T = Universal_Integer
2987 or else T = Universal_Real;
2988 else
2989 Get_First_Interp (N, Index, It);
2991 while Present (It.Typ) loop
2993 if Base_Type (It.Typ) = Base_Type (Standard_Integer)
2994 or else It.Typ = Universal_Integer
2995 or else It.Typ = Universal_Real
2996 then
2997 return True;
2998 end if;
3000 Get_Next_Interp (Index, It);
3001 end loop;
3002 end if;
3004 return False;
3005 end Is_Integer_Or_Universal;
3007 ----------------------------
3008 -- Set_Mixed_Mode_Operand --
3009 ----------------------------
3011 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id) is
3012 Index : Interp_Index;
3013 It : Interp;
3015 begin
3016 if Universal_Interpretation (N) = Universal_Integer then
3018 -- A universal integer literal is resolved as standard integer
3019 -- except in the case of a fixed-point result, where we leave
3020 -- it as universal (to be handled by Exp_Fixd later on)
3022 if Is_Fixed_Point_Type (T) then
3023 Resolve (N, Universal_Integer);
3024 else
3025 Resolve (N, Standard_Integer);
3026 end if;
3028 elsif Universal_Interpretation (N) = Universal_Real
3029 and then (T = Base_Type (Standard_Integer)
3030 or else T = Universal_Integer
3031 or else T = Universal_Real)
3032 then
3033 -- A universal real can appear in a fixed-type context. We resolve
3034 -- the literal with that context, even though this might raise an
3035 -- exception prematurely (the other operand may be zero).
3037 Resolve (N, B_Typ);
3039 elsif Etype (N) = Base_Type (Standard_Integer)
3040 and then T = Universal_Real
3041 and then Is_Overloaded (N)
3042 then
3043 -- Integer arg in mixed-mode operation. Resolve with universal
3044 -- type, in case preference rule must be applied.
3046 Resolve (N, Universal_Integer);
3048 elsif Etype (N) = T
3049 and then B_Typ /= Universal_Fixed
3050 then
3051 -- Not a mixed-mode operation. Resolve with context.
3053 Resolve (N, B_Typ);
3055 elsif Etype (N) = Any_Fixed then
3057 -- N may itself be a mixed-mode operation, so use context type.
3059 Resolve (N, B_Typ);
3061 elsif Is_Fixed_Point_Type (T)
3062 and then B_Typ = Universal_Fixed
3063 and then Is_Overloaded (N)
3064 then
3065 -- Must be (fixed * fixed) operation, operand must have one
3066 -- compatible interpretation.
3068 Resolve (N, Any_Fixed);
3070 elsif Is_Fixed_Point_Type (B_Typ)
3071 and then (T = Universal_Real
3072 or else Is_Fixed_Point_Type (T))
3073 and then Is_Overloaded (N)
3074 then
3075 -- C * F(X) in a fixed context, where C is a real literal or a
3076 -- fixed-point expression. F must have either a fixed type
3077 -- interpretation or an integer interpretation, but not both.
3079 Get_First_Interp (N, Index, It);
3081 while Present (It.Typ) loop
3082 if Base_Type (It.Typ) = Base_Type (Standard_Integer) then
3084 if Analyzed (N) then
3085 Error_Msg_N ("ambiguous operand in fixed operation", N);
3086 else
3087 Resolve (N, Standard_Integer);
3088 end if;
3090 elsif Is_Fixed_Point_Type (It.Typ) then
3092 if Analyzed (N) then
3093 Error_Msg_N ("ambiguous operand in fixed operation", N);
3094 else
3095 Resolve (N, It.Typ);
3096 end if;
3097 end if;
3099 Get_Next_Interp (Index, It);
3100 end loop;
3102 -- Reanalyze the literal with the fixed type of the context.
3104 if N = L then
3105 Set_Analyzed (R, False);
3106 Resolve (R, B_Typ);
3107 else
3108 Set_Analyzed (L, False);
3109 Resolve (L, B_Typ);
3110 end if;
3112 else
3113 Resolve (N);
3114 end if;
3115 end Set_Mixed_Mode_Operand;
3117 ----------------------
3118 -- Set_Operand_Type --
3119 ----------------------
3121 procedure Set_Operand_Type (N : Node_Id) is
3122 begin
3123 if Etype (N) = Universal_Integer
3124 or else Etype (N) = Universal_Real
3125 then
3126 Set_Etype (N, T);
3127 end if;
3128 end Set_Operand_Type;
3130 -- Start of processing for Resolve_Arithmetic_Op
3132 begin
3133 if Comes_From_Source (N)
3134 and then Ekind (Entity (N)) = E_Function
3135 and then Is_Imported (Entity (N))
3136 and then Is_Intrinsic_Subprogram (Entity (N))
3137 then
3138 Resolve_Intrinsic_Operator (N, Typ);
3139 return;
3141 -- Special-case for mixed-mode universal expressions or fixed point
3142 -- type operation: each argument is resolved separately. The same
3143 -- treatment is required if one of the operands of a fixed point
3144 -- operation is universal real, since in this case we don't do a
3145 -- conversion to a specific fixed-point type (instead the expander
3146 -- takes care of the case).
3148 elsif (B_Typ = Universal_Integer
3149 or else B_Typ = Universal_Real)
3150 and then Present (Universal_Interpretation (L))
3151 and then Present (Universal_Interpretation (R))
3152 then
3153 Resolve (L, Universal_Interpretation (L));
3154 Resolve (R, Universal_Interpretation (R));
3155 Set_Etype (N, B_Typ);
3157 elsif (B_Typ = Universal_Real
3158 or else Etype (N) = Universal_Fixed
3159 or else (Etype (N) = Any_Fixed
3160 and then Is_Fixed_Point_Type (B_Typ))
3161 or else (Is_Fixed_Point_Type (B_Typ)
3162 and then (Is_Integer_Or_Universal (L)
3163 or else
3164 Is_Integer_Or_Universal (R))))
3165 and then (Nkind (N) = N_Op_Multiply or else
3166 Nkind (N) = N_Op_Divide)
3167 then
3168 if TL = Universal_Integer or else TR = Universal_Integer then
3169 Check_For_Visible_Operator (N, B_Typ);
3170 end if;
3172 -- If context is a fixed type and one operand is integer, the
3173 -- other is resolved with the type of the context.
3175 if Is_Fixed_Point_Type (B_Typ)
3176 and then (Base_Type (TL) = Base_Type (Standard_Integer)
3177 or else TL = Universal_Integer)
3178 then
3179 Resolve (R, B_Typ);
3180 Resolve (L, TL);
3182 elsif Is_Fixed_Point_Type (B_Typ)
3183 and then (Base_Type (TR) = Base_Type (Standard_Integer)
3184 or else TR = Universal_Integer)
3185 then
3186 Resolve (L, B_Typ);
3187 Resolve (R, TR);
3189 else
3190 Set_Mixed_Mode_Operand (L, TR);
3191 Set_Mixed_Mode_Operand (R, TL);
3192 end if;
3194 if Etype (N) = Universal_Fixed
3195 or else Etype (N) = Any_Fixed
3196 then
3197 if B_Typ = Universal_Fixed
3198 and then Nkind (Parent (N)) /= N_Type_Conversion
3199 and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
3200 then
3201 Error_Msg_N
3202 ("type cannot be determined from context!", N);
3203 Error_Msg_N
3206 Set_Etype (L, Any_Type);
3207 Set_Etype (R, Any_Type);
3209 else
3210 if Ada_83
3211 and then Etype (N) = Universal_Fixed
3212 and then Nkind (Parent (N)) /= N_Type_Conversion
3213 and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
3214 then
3215 Error_Msg_N
3216 ("(Ada 83) fixed-point operation " &
3217 "needs explicit conversion",
3218 N);
3219 end if;
3221 Set_Etype (N, B_Typ);
3222 end if;
3224 elsif Is_Fixed_Point_Type (B_Typ)
3225 and then (Is_Integer_Or_Universal (L)
3226 or else Nkind (L) = N_Real_Literal
3227 or else Nkind (R) = N_Real_Literal
3228 or else
3229 Is_Integer_Or_Universal (R))
3230 then
3231 Set_Etype (N, B_Typ);
3233 elsif Etype (N) = Any_Fixed then
3235 -- If no previous errors, this is only possible if one operand
3236 -- is overloaded and the context is universal. Resolve as such.
3238 Set_Etype (N, B_Typ);
3239 end if;
3241 else
3242 if (TL = Universal_Integer or else TL = Universal_Real)
3243 and then (TR = Universal_Integer or else TR = Universal_Real)
3244 then
3245 Check_For_Visible_Operator (N, B_Typ);
3246 end if;
3248 -- If the context is Universal_Fixed and the operands are also
3249 -- universal fixed, this is an error, unless there is only one
3250 -- applicable fixed_point type (usually duration).
3252 if B_Typ = Universal_Fixed
3253 and then Etype (L) = Universal_Fixed
3254 then
3255 T := Unique_Fixed_Point_Type (N);
3257 if T = Any_Type then
3258 Set_Etype (N, T);
3259 return;
3260 else
3261 Resolve (L, T);
3262 Resolve (R, T);
3263 end if;
3265 else
3266 Resolve (L, B_Typ);
3267 Resolve (R, B_Typ);
3268 end if;
3270 -- If one of the arguments was resolved to a non-universal type.
3271 -- label the result of the operation itself with the same type.
3272 -- Do the same for the universal argument, if any.
3274 T := Intersect_Types (L, R);
3275 Set_Etype (N, Base_Type (T));
3276 Set_Operand_Type (L);
3277 Set_Operand_Type (R);
3278 end if;
3280 Generate_Operator_Reference (N, Typ);
3281 Eval_Arithmetic_Op (N);
3283 -- Set overflow and division checking bit. Much cleverer code needed
3284 -- here eventually and perhaps the Resolve routines should be separated
3285 -- for the various arithmetic operations, since they will need
3286 -- different processing. ???
3288 if Nkind (N) in N_Op then
3289 if not Overflow_Checks_Suppressed (Etype (N)) then
3290 Enable_Overflow_Check (N);
3291 end if;
3293 -- Give warning if explicit division by zero
3295 if (Nkind (N) = N_Op_Divide
3296 or else Nkind (N) = N_Op_Rem
3297 or else Nkind (N) = N_Op_Mod)
3298 and then not Division_Checks_Suppressed (Etype (N))
3299 then
3300 Rop := Right_Opnd (N);
3302 if Compile_Time_Known_Value (Rop)
3303 and then ((Is_Integer_Type (Etype (Rop))
3304 and then Expr_Value (Rop) = Uint_0)
3305 or else
3306 (Is_Real_Type (Etype (Rop))
3307 and then Expr_Value_R (Rop) = Ureal_0))
3308 then
3309 Apply_Compile_Time_Constraint_Error
3310 (N, "division by zero?", CE_Divide_By_Zero,
3311 Loc => Sloc (Right_Opnd (N)));
3313 -- Otherwise just set the flag to check at run time
3315 else
3316 Set_Do_Division_Check (N);
3317 end if;
3318 end if;
3319 end if;
3321 Check_Unset_Reference (L);
3322 Check_Unset_Reference (R);
3323 end Resolve_Arithmetic_Op;
3325 ------------------
3326 -- Resolve_Call --
3327 ------------------
3329 procedure Resolve_Call (N : Node_Id; Typ : Entity_Id) is
3330 Loc : constant Source_Ptr := Sloc (N);
3331 Subp : constant Node_Id := Name (N);
3332 Nam : Entity_Id;
3333 I : Interp_Index;
3334 It : Interp;
3335 Norm_OK : Boolean;
3336 Scop : Entity_Id;
3337 Decl : Node_Id;
3339 begin
3340 -- The context imposes a unique interpretation with type Typ on
3341 -- a procedure or function call. Find the entity of the subprogram
3342 -- that yields the expected type, and propagate the corresponding
3343 -- formal constraints on the actuals. The caller has established
3344 -- that an interpretation exists, and emitted an error if not unique.
3346 -- First deal with the case of a call to an access-to-subprogram,
3347 -- dereference made explicit in Analyze_Call.
3349 if Ekind (Etype (Subp)) = E_Subprogram_Type then
3350 if not Is_Overloaded (Subp) then
3351 Nam := Etype (Subp);
3353 else
3354 -- Find the interpretation whose type (a subprogram type)
3355 -- has a return type that is compatible with the context.
3356 -- Analysis of the node has established that one exists.
3358 Get_First_Interp (Subp, I, It);
3359 Nam := Empty;
3361 while Present (It.Typ) loop
3362 if Covers (Typ, Etype (It.Typ)) then
3363 Nam := It.Typ;
3364 exit;
3365 end if;
3367 Get_Next_Interp (I, It);
3368 end loop;
3370 if No (Nam) then
3371 raise Program_Error;
3372 end if;
3373 end if;
3375 -- If the prefix is not an entity, then resolve it
3377 if not Is_Entity_Name (Subp) then
3378 Resolve (Subp, Nam);
3379 end if;
3381 -- For an indirect call, we always invalidate checks, since we
3382 -- do not know whether the subprogram is local or global. Yes
3383 -- we could do better here, e.g. by knowing that there are no
3384 -- local subprograms, but it does not seem worth the effort.
3385 -- Similarly, we kill al knowledge of current constant values.
3387 Kill_Current_Values;
3389 -- If this is a procedure call which is really an entry call, do
3390 -- the conversion of the procedure call to an entry call. Protected
3391 -- operations use the same circuitry because the name in the call
3392 -- can be an arbitrary expression with special resolution rules.
3394 elsif Nkind (Subp) = N_Selected_Component
3395 or else Nkind (Subp) = N_Indexed_Component
3396 or else (Is_Entity_Name (Subp)
3397 and then Ekind (Entity (Subp)) = E_Entry)
3398 then
3399 Resolve_Entry_Call (N, Typ);
3400 Check_Elab_Call (N);
3402 -- Kill checks and constant values, as above for indirect case
3403 -- Who knows what happens when another task is activated?
3405 Kill_Current_Values;
3406 return;
3408 -- Normal subprogram call with name established in Resolve
3410 elsif not (Is_Type (Entity (Subp))) then
3411 Nam := Entity (Subp);
3412 Set_Entity_With_Style_Check (Subp, Nam);
3413 Generate_Reference (Nam, Subp);
3415 -- Otherwise we must have the case of an overloaded call
3417 else
3418 pragma Assert (Is_Overloaded (Subp));
3419 Nam := Empty; -- We know that it will be assigned in loop below.
3421 Get_First_Interp (Subp, I, It);
3423 while Present (It.Typ) loop
3424 if Covers (Typ, It.Typ) then
3425 Nam := It.Nam;
3426 Set_Entity_With_Style_Check (Subp, Nam);
3427 Generate_Reference (Nam, Subp);
3428 exit;
3429 end if;
3431 Get_Next_Interp (I, It);
3432 end loop;
3433 end if;
3435 -- Check that a call to Current_Task does not occur in an entry body
3437 if Is_RTE (Nam, RE_Current_Task) then
3438 declare
3439 P : Node_Id;
3441 begin
3442 P := N;
3443 loop
3444 P := Parent (P);
3445 exit when No (P);
3447 if Nkind (P) = N_Entry_Body then
3448 Error_Msg_NE
3450 N, Nam);
3451 exit;
3452 end if;
3453 end loop;
3454 end;
3455 end if;
3457 -- Cannot call thread body directly
3459 if Is_Thread_Body (Nam) then
3461 end if;
3463 -- If the subprogram is not global, then kill all checks. This is
3464 -- a bit conservative, since in many cases we could do better, but
3465 -- it is not worth the effort. Similarly, we kill constant values.
3466 -- However we do not need to do this for internal entities (unless
3467 -- they are inherited user-defined subprograms), since they are not
3468 -- in the business of molesting global values.
3470 if not Is_Library_Level_Entity (Nam)
3471 and then (Comes_From_Source (Nam)
3472 or else (Present (Alias (Nam))
3473 and then Comes_From_Source (Alias (Nam))))
3474 then
3475 Kill_Current_Values;
3476 end if;
3478 -- Check for call to obsolescent subprogram
3480 if Warn_On_Obsolescent_Feature then
3481 Decl := Parent (Parent (Nam));
3483 if Nkind (Decl) = N_Subprogram_Declaration
3484 and then Is_List_Member (Decl)
3485 and then Nkind (Next (Decl)) = N_Pragma
3486 then
3487 declare
3488 P : constant Node_Id := Next (Decl);
3490 begin
3491 if Chars (P) = Name_Obsolescent then
3494 if Pragma_Argument_Associations (P) /= No_List then
3495 Name_Buffer (1) := '|';
3496 Name_Buffer (2) := '?';
3497 Name_Len := 2;
3498 Add_String_To_Name_Buffer
3499 (Strval (Expression
3500 (First (Pragma_Argument_Associations (P)))));
3501 Error_Msg_N (Name_Buffer (1 .. Name_Len), N);
3502 end if;
3503 end if;
3504 end;
3505 end if;
3506 end if;
3508 -- Check that a procedure call does not occur in the context
3509 -- of the entry call statement of a conditional or timed
3510 -- entry call. Note that the case of a call to a subprogram
3511 -- renaming of an entry will also be rejected. The test
3512 -- for N not being an N_Entry_Call_Statement is defensive,
3513 -- covering the possibility that the processing of entry
3514 -- calls might reach this point due to later modifications
3515 -- of the code above.
3517 if Nkind (Parent (N)) = N_Entry_Call_Alternative
3518 and then Nkind (N) /= N_Entry_Call_Statement
3519 and then Entry_Call_Statement (Parent (N)) = N
3520 then
3522 end if;
3524 -- Check that this is not a call to a protected procedure or
3525 -- entry from within a protected function.
3527 if Ekind (Current_Scope) = E_Function
3528 and then Ekind (Scope (Current_Scope)) = E_Protected_Type
3529 and then Ekind (Nam) /= E_Function
3530 and then Scope (Nam) = Scope (Current_Scope)
3531 then
3535 end if;
3537 -- Freeze the subprogram name if not in default expression. Note
3538 -- that we freeze procedure calls as well as function calls.
3539 -- Procedure calls are not frozen according to the rules (RM
3540 -- 13.14(14)) because it is impossible to have a procedure call to
3541 -- a non-frozen procedure in pure Ada, but in the code that we
3542 -- generate in the expander, this rule needs extending because we
3543 -- can generate procedure calls that need freezing.
3545 if Is_Entity_Name (Subp) and then not In_Default_Expression then
3546 Freeze_Expression (Subp);
3547 end if;
3549 -- For a predefined operator, the type of the result is the type
3550 -- imposed by context, except for a predefined operation on universal
3551 -- fixed. Otherwise The type of the call is the type returned by the
3552 -- subprogram being called.
3554 if Is_Predefined_Op (Nam) then
3555 if Etype (N) /= Universal_Fixed then
3556 Set_Etype (N, Typ);
3557 end if;
3559 -- If the subprogram returns an array type, and the context
3560 -- requires the component type of that array type, the node is
3561 -- really an indexing of the parameterless call. Resolve as such.
3562 -- A pathological case occurs when the type of the component is
3563 -- an access to the array type. In this case the call is truly
3564 -- ambiguous.
3566 elsif Needs_No_Actuals (Nam)
3567 and then
3568 ((Is_Array_Type (Etype (Nam))
3569 and then Covers (Typ, Component_Type (Etype (Nam))))
3570 or else (Is_Access_Type (Etype (Nam))
3571 and then Is_Array_Type (Designated_Type (Etype (Nam)))
3572 and then
3573 Covers (Typ,
3574 Component_Type (Designated_Type (Etype (Nam))))))
3575 then
3576 declare
3577 Index_Node : Node_Id;
3578 New_Subp : Node_Id;
3579 Ret_Type : constant Entity_Id := Etype (Nam);
3581 begin
3582 if Is_Access_Type (Ret_Type)
3583 and then Ret_Type = Component_Type (Designated_Type (Ret_Type))
3584 then
3585 Error_Msg_N
3587 else
3588 New_Subp := Relocate_Node (Subp);
3589 Set_Entity (Subp, Nam);
3591 if Component_Type (Ret_Type) /= Any_Type then
3592 Index_Node :=
3593 Make_Indexed_Component (Loc,
3594 Prefix =>
3595 Make_Function_Call (Loc,
3596 Name => New_Subp),
3597 Expressions => Parameter_Associations (N));
3599 -- Since we are correcting a node classification error made
3600 -- by the parser, we call Replace rather than Rewrite.
3602 Replace (N, Index_Node);
3603 Set_Etype (Prefix (N), Ret_Type);
3604 Set_Etype (N, Typ);
3605 Resolve_Indexed_Component (N, Typ);
3606 Check_Elab_Call (Prefix (N));
3607 end if;
3608 end if;
3610 return;
3611 end;
3613 else
3614 Set_Etype (N, Etype (Nam));
3615 end if;
3617 -- In the case where the call is to an overloaded subprogram, Analyze
3618 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
3619 -- such a case Normalize_Actuals needs to be called once more to order
3620 -- the actuals correctly. Otherwise the call will have the ordering
3621 -- given by the last overloaded subprogram whether this is the correct
3622 -- one being called or not.
3624 if Is_Overloaded (Subp) then
3625 Normalize_Actuals (N, Nam, False, Norm_OK);
3626 pragma Assert (Norm_OK);
3627 end if;
3629 -- In any case, call is fully resolved now. Reset Overload flag, to
3630 -- prevent subsequent overload resolution if node is analyzed again
3632 Set_Is_Overloaded (Subp, False);
3633 Set_Is_Overloaded (N, False);
3635 -- If we are calling the current subprogram from immediately within
3636 -- its body, then that is the case where we can sometimes detect
3637 -- cases of infinite recursion statically. Do not try this in case
3638 -- restriction No_Recursion is in effect anyway.
3640 Scop := Current_Scope;
3642 if Nam = Scop
3643 and then not Restrictions (No_Recursion)
3644 and then Check_Infinite_Recursion (N)
3645 then
3646 -- Here we detected and flagged an infinite recursion, so we do
3647 -- not need to test the case below for further warnings.
3649 null;
3651 -- If call is to immediately containing subprogram, then check for
3652 -- the case of a possible run-time detectable infinite recursion.
3654 else
3655 while Scop /= Standard_Standard loop
3656 if Nam = Scop then
3657 -- Although in general recursion is not statically checkable,
3658 -- the case of calling an immediately containing subprogram
3659 -- is easy to catch.
3661 Check_Restriction (No_Recursion, N);
3663 -- If the recursive call is to a parameterless procedure, then
3664 -- even if we can't statically detect infinite recursion, this
3665 -- is pretty suspicious, and we output a warning. Furthermore,
3666 -- we will try later to detect some cases here at run time by
3667 -- expanding checking code (see Detect_Infinite_Recursion in
3668 -- package Exp_Ch6).
3669 -- If the recursive call is within a handler we do not emit a
3670 -- warning, because this is a common idiom: loop until input
3671 -- is correct, catch illegal input in handler and restart.
3673 if No (First_Formal (Nam))
3674 and then Etype (Nam) = Standard_Void_Type
3675 and then not Error_Posted (N)
3676 and then Nkind (Parent (N)) /= N_Exception_Handler
3677 then
3678 Set_Has_Recursive_Call (Nam);
3681 end if;
3683 exit;
3684 end if;
3686 Scop := Scope (Scop);
3687 end loop;
3688 end if;
3690 -- If subprogram name is a predefined operator, it was given in
3691 -- functional notation. Replace call node with operator node, so
3692 -- that actuals can be resolved appropriately.
3694 if Is_Predefined_Op (Nam) or else Ekind (Nam) = E_Operator then
3695 Make_Call_Into_Operator (N, Typ, Entity (Name (N)));
3696 return;
3698 elsif Present (Alias (Nam))
3699 and then Is_Predefined_Op (Alias (Nam))
3700 then
3701 Resolve_Actuals (N, Nam);
3702 Make_Call_Into_Operator (N, Typ, Alias (Nam));
3703 return;
3704 end if;
3706 -- Create a transient scope if the resulting type requires it
3708 -- There are 3 notable exceptions: in init procs, the transient scope
3709 -- overhead is not needed and even incorrect due to the actual expansion
3710 -- of adjust calls; the second case is enumeration literal pseudo calls,
3711 -- the other case is intrinsic subprograms (Unchecked_Conversion and
3712 -- source information functions) that do not use the secondary stack
3713 -- even though the return type is unconstrained.
3715 -- If this is an initialization call for a type whose initialization
3716 -- uses the secondary stack, we also need to create a transient scope
3717 -- for it, precisely because we will not do it within the init proc
3718 -- itself.
3720 if Expander_Active
3721 and then Is_Type (Etype (Nam))
3722 and then Requires_Transient_Scope (Etype (Nam))
3723 and then Ekind (Nam) /= E_Enumeration_Literal
3724 and then not Within_Init_Proc
3725 and then not Is_Intrinsic_Subprogram (Nam)
3726 then
3727 Establish_Transient_Scope
3728 (N, Sec_Stack => not Functions_Return_By_DSP_On_Target);
3730 -- If the call appears within the bounds of a loop, it will
3731 -- be rewritten and reanalyzed, nothing left to do here.
3733 if Nkind (N) /= N_Function_Call then
3734 return;
3735 end if;
3737 elsif Is_Init_Proc (Nam)
3738 and then not Within_Init_Proc
3739 then
3740 Check_Initialization_Call (N, Nam);
3741 end if;
3743 -- A protected function cannot be called within the definition of the
3744 -- enclosing protected type.
3746 if Is_Protected_Type (Scope (Nam))
3747 and then In_Open_Scopes (Scope (Nam))
3748 and then not Has_Completion (Scope (Nam))
3749 then
3750 Error_Msg_NE
3752 end if;
3754 -- Propagate interpretation to actuals, and add default expressions
3755 -- where needed.
3757 if Present (First_Formal (Nam)) then
3758 Resolve_Actuals (N, Nam);
3760 -- Overloaded literals are rewritten as function calls, for
3761 -- purpose of resolution. After resolution, we can replace
3762 -- the call with the literal itself.
3764 elsif Ekind (Nam) = E_Enumeration_Literal then
3765 Copy_Node (Subp, N);
3766 Resolve_Entity_Name (N, Typ);
3768 -- Avoid validation, since it is a static function call
3770 return;
3771 end if;
3773 -- If the subprogram is a primitive operation, check whether or not
3774 -- it is a correct dispatching call.
3776 if Is_Overloadable (Nam)
3777 and then Is_Dispatching_Operation (Nam)
3778 then
3779 Check_Dispatching_Call (N);
3781 elsif Is_Abstract (Nam)
3782 and then not In_Instance
3783 then
3785 end if;
3787 if Is_Intrinsic_Subprogram (Nam) then
3788 Check_Intrinsic_Call (N);
3789 end if;
3791 -- If we fall through we definitely have a non-static call
3793 Check_Elab_Call (N);
3794 end Resolve_Call;
3796 -------------------------------
3797 -- Resolve_Character_Literal --
3798 -------------------------------
3800 procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id) is
3801 B_Typ : constant Entity_Id := Base_Type (Typ);
3802 C : Entity_Id;
3804 begin
3805 -- Verify that the character does belong to the type of the context
3807 Set_Etype (N, B_Typ);
3808 Eval_Character_Literal (N);
3810 -- Wide_Character literals must always be defined, since the set of
3811 -- wide character literals is complete, i.e. if a character literal
3812 -- is accepted by the parser, then it is OK for wide character.
3814 if Root_Type (B_Typ) = Standard_Wide_Character then
3815 return;
3817 -- Always accept character literal for type Any_Character, which
3818 -- occurs in error situations and in comparisons of literals, both
3819 -- of which should accept all literals.
3821 elsif B_Typ = Any_Character then
3822 return;
3824 -- For Standard.Character or a type derived from it, check that
3825 -- the literal is in range
3827 elsif Root_Type (B_Typ) = Standard_Character then
3828 if In_Character_Range (Char_Literal_Value (N)) then
3829 return;
3830 end if;
3832 -- If the entity is already set, this has already been resolved in
3833 -- a generic context, or comes from expansion. Nothing else to do.
3835 elsif Present (Entity (N)) then
3836 return;
3838 -- Otherwise we have a user defined character type, and we can use
3839 -- the standard visibility mechanisms to locate the referenced entity
3841 else
3842 C := Current_Entity (N);
3844 while Present (C) loop
3845 if Etype (C) = B_Typ then
3846 Set_Entity_With_Style_Check (N, C);
3847 Generate_Reference (C, N);
3848 return;
3849 end if;
3851 C := Homonym (C);
3852 end loop;
3853 end if;
3855 -- If we fall through, then the literal does not match any of the
3856 -- entries of the enumeration type. This isn't just a constraint
3857 -- error situation, it is an illegality (see RM 4.2).
3859 Error_Msg_NE
3861 end Resolve_Character_Literal;
3863 ---------------------------
3864 -- Resolve_Comparison_Op --
3865 ---------------------------
3867 -- Context requires a boolean type, and plays no role in resolution.
3868 -- Processing identical to that for equality operators. The result
3869 -- type is the base type, which matters when pathological subtypes of
3870 -- booleans with limited ranges are used.
3872 procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id) is
3873 L : constant Node_Id := Left_Opnd (N);
3874 R : constant Node_Id := Right_Opnd (N);
3875 T : Entity_Id;
3877 begin
3878 Check_Direct_Boolean_Op (N);
3880 -- If this is an intrinsic operation which is not predefined, use
3881 -- the types of its declared arguments to resolve the possibly
3882 -- overloaded operands. Otherwise the operands are unambiguous and
3883 -- specify the expected type.
3885 if Scope (Entity (N)) /= Standard_Standard then
3886 T := Etype (First_Entity (Entity (N)));
3887 else
3888 T := Find_Unique_Type (L, R);
3890 if T = Any_Fixed then
3891 T := Unique_Fixed_Point_Type (L);
3892 end if;
3893 end if;
3895 Set_Etype (N, Base_Type (Typ));
3896 Generate_Reference (T, N, ' ');
3898 if T /= Any_Type then
3899 if T = Any_String
3900 or else T = Any_Composite
3901 or else T = Any_Character
3902 then
3903 if T = Any_Character then
3904 Ambiguous_Character (L);
3905 else
3907 end if;
3909 Set_Etype (N, Any_Type);
3910 return;
3912 else
3913 if Comes_From_Source (N)
3914 and then Has_Unchecked_Union (T)
3915 then
3916 Error_Msg_N
3918 end if;
3920 Resolve (L, T);
3921 Resolve (R, T);
3922 Check_Unset_Reference (L);
3923 Check_Unset_Reference (R);
3924 Generate_Operator_Reference (N, T);
3925 Eval_Relational_Op (N);
3926 end if;
3927 end if;
3928 end Resolve_Comparison_Op;
3930 ------------------------------------
3931 -- Resolve_Conditional_Expression --
3932 ------------------------------------
3934 procedure Resolve_Conditional_Expression (N : Node_Id; Typ : Entity_Id) is
3935 Condition : constant Node_Id := First (Expressions (N));
3936 Then_Expr : constant Node_Id := Next (Condition);
3937 Else_Expr : constant Node_Id := Next (Then_Expr);
3939 begin
3940 Resolve (Condition, Standard_Boolean);
3941 Resolve (Then_Expr, Typ);
3942 Resolve (Else_Expr, Typ);
3944 Set_Etype (N, Typ);
3945 Eval_Conditional_Expression (N);
3946 end Resolve_Conditional_Expression;
3948 -----------------------------------------
3949 -- Resolve_Discrete_Subtype_Indication --
3950 -----------------------------------------
3952 procedure Resolve_Discrete_Subtype_Indication
3953 (N : Node_Id;
3954 Typ : Entity_Id)
3955 is
3956 R : Node_Id;
3957 S : Entity_Id;
3959 begin
3960 Analyze (Subtype_Mark (N));
3961 S := Entity (Subtype_Mark (N));
3963 if Nkind (Constraint (N)) /= N_Range_Constraint then
3965 Set_Etype (N, Any_Type);
3967 else
3968 R := Range_Expression (Constraint (N));
3970 if R = Error then
3971 return;
3972 end if;
3974 Analyze (R);
3976 if Base_Type (S) /= Base_Type (Typ) then
3977 Error_Msg_NE
3980 -- Rewrite the constraint as a range of Typ
3981 -- to allow compilation to proceed further.
3983 Set_Etype (N, Typ);
3984 Rewrite (Low_Bound (R),
3985 Make_Attribute_Reference (Sloc (Low_Bound (R)),
3986 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
3987 Attribute_Name => Name_First));
3988 Rewrite (High_Bound (R),
3989 Make_Attribute_Reference (Sloc (High_Bound (R)),
3990 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
3991 Attribute_Name => Name_First));
3993 else
3994 Resolve (R, Typ);
3995 Set_Etype (N, Etype (R));
3997 -- Additionally, we must check that the bounds are compatible
3998 -- with the given subtype, which might be different from the
3999 -- type of the context.
4001 Apply_Range_Check (R, S);
4003 -- ??? If the above check statically detects a Constraint_Error
4004 -- it replaces the offending bound(s) of the range R with a
4005 -- Constraint_Error node. When the itype which uses these bounds
4006 -- is frozen the resulting call to Duplicate_Subexpr generates
4007 -- a new temporary for the bounds.
4009 -- Unfortunately there are other itypes that are also made depend
4010 -- on these bounds, so when Duplicate_Subexpr is called they get
4011 -- a forward reference to the newly created temporaries and Gigi
4012 -- aborts on such forward references. This is probably sign of a
4013 -- more fundamental problem somewhere else in either the order of
4014 -- itype freezing or the way certain itypes are constructed.
4016 -- To get around this problem we call Remove_Side_Effects right
4017 -- away if either bounds of R are a Constraint_Error.
4019 declare
4020 L : constant Node_Id := Low_Bound (R);
4021 H : constant Node_Id := High_Bound (R);
4023 begin
4024 if Nkind (L) = N_Raise_Constraint_Error then
4025 Remove_Side_Effects (L);
4026 end if;
4028 if Nkind (H) = N_Raise_Constraint_Error then
4029 Remove_Side_Effects (H);
4030 end if;
4031 end;
4033 Check_Unset_Reference (Low_Bound (R));
4034 Check_Unset_Reference (High_Bound (R));
4035 end if;
4036 end if;
4037 end Resolve_Discrete_Subtype_Indication;
4039 -------------------------
4040 -- Resolve_Entity_Name --
4041 -------------------------
4043 -- Used to resolve identifiers and expanded names
4045 procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id) is
4046 E : constant Entity_Id := Entity (N);
4048 begin
4049 -- If garbage from errors, set to Any_Type and return
4051 if No (E) and then Total_Errors_Detected /= 0 then
4052 Set_Etype (N, Any_Type);
4053 return;
4054 end if;
4056 -- Replace named numbers by corresponding literals. Note that this is
4057 -- the one case where Resolve_Entity_Name must reset the Etype, since
4058 -- it is currently marked as universal.
4060 if Ekind (E) = E_Named_Integer then
4061 Set_Etype (N, Typ);
4062 Eval_Named_Integer (N);
4064 elsif Ekind (E) = E_Named_Real then
4065 Set_Etype (N, Typ);
4066 Eval_Named_Real (N);
4068 -- Allow use of subtype only if it is a concurrent type where we are
4069 -- currently inside the body. This will eventually be expanded
4070 -- into a call to Self (for tasks) or _object (for protected
4071 -- objects). Any other use of a subtype is invalid.
4073 elsif Is_Type (E) then
4074 if Is_Concurrent_Type (E)
4075 and then In_Open_Scopes (E)
4076 then
4077 null;
4078 else
4079 Error_Msg_N
4081 end if;
4083 -- Check discriminant use if entity is discriminant in current scope,
4084 -- i.e. discriminant of record or concurrent type currently being
4085 -- analyzed. Uses in corresponding body are unrestricted.
4087 elsif Ekind (E) = E_Discriminant
4088 and then Scope (E) = Current_Scope
4089 and then not Has_Completion (Current_Scope)
4090 then
4091 Check_Discriminant_Use (N);
4093 -- A parameterless generic function cannot appear in a context that
4094 -- requires resolution.
4096 elsif Ekind (E) = E_Generic_Function then
4099 elsif Ekind (E) = E_Out_Parameter
4100 and then Ada_83
4101 and then (Nkind (Parent (N)) in N_Op
4102 or else (Nkind (Parent (N)) = N_Assignment_Statement
4103 and then N = Expression (Parent (N)))
4104 or else Nkind (Parent (N)) = N_Explicit_Dereference)
4105 then
4108 -- In all other cases, just do the possible static evaluation
4110 else
4111 -- A deferred constant that appears in an expression must have
4112 -- a completion, unless it has been removed by in-place expansion
4113 -- of an aggregate.
4115 if Ekind (E) = E_Constant
4116 and then Comes_From_Source (E)
4117 and then No (Constant_Value (E))
4118 and then Is_Frozen (Etype (E))
4119 and then not In_Default_Expression
4120 and then not Is_Imported (E)
4121 then
4123 if No_Initialization (Parent (E))
4124 or else (Present (Full_View (E))
4125 and then No_Initialization (Parent (Full_View (E))))
4126 then
4127 null;
4128 else
4129 Error_Msg_N (
4131 end if;
4132 end if;
4134 Eval_Entity_Name (N);
4135 end if;
4136 end Resolve_Entity_Name;
4138 -------------------
4139 -- Resolve_Entry --
4140 -------------------
4142 procedure Resolve_Entry (Entry_Name : Node_Id) is
4143 Loc : constant Source_Ptr := Sloc (Entry_Name);
4144 Nam : Entity_Id;
4145 New_N : Node_Id;
4146 S : Entity_Id;
4147 Tsk : Entity_Id;
4148 E_Name : Node_Id;
4149 Index : Node_Id;
4151 function Actual_Index_Type (E : Entity_Id) return Entity_Id;
4152 -- If the bounds of the entry family being called depend on task
4153 -- discriminants, build a new index subtype where a discriminant is
4154 -- replaced with the value of the discriminant of the target task.
4155 -- The target task is the prefix of the entry name in the call.
4157 -----------------------
4158 -- Actual_Index_Type --
4159 -----------------------
4161 function Actual_Index_Type (E : Entity_Id) return Entity_Id is
4162 Typ : constant Entity_Id := Entry_Index_Type (E);
4163 Tsk : constant Entity_Id := Scope (E);
4164 Lo : constant Node_Id := Type_Low_Bound (Typ);
4165 Hi : constant Node_Id := Type_High_Bound (Typ);
4166 New_T : Entity_Id;
4168 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id;
4169 -- If the bound is given by a discriminant, replace with a reference
4170 -- to the discriminant of the same name in the target task.
4171 -- If the entry name is the target of a requeue statement and the
4172 -- entry is in the current protected object, the bound to be used
4173 -- is the discriminal of the object (see apply_range_checks for
4174 -- details of the transformation).
4176 -----------------------------
4177 -- Actual_Discriminant_Ref --
4178 -----------------------------
4180 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id is
4181 Typ : constant Entity_Id := Etype (Bound);
4182 Ref : Node_Id;
4184 begin
4185 Remove_Side_Effects (Bound);
4187 if not Is_Entity_Name (Bound)
4188 or else Ekind (Entity (Bound)) /= E_Discriminant
4189 then
4190 return Bound;
4192 elsif Is_Protected_Type (Tsk)
4193 and then In_Open_Scopes (Tsk)
4194 and then Nkind (Parent (Entry_Name)) = N_Requeue_Statement
4195 then
4196 return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc);
4198 else
4199 Ref :=
4200 Make_Selected_Component (Loc,
4201 Prefix => New_Copy_Tree (Prefix (Prefix (Entry_Name))),
4202 Selector_Name => New_Occurrence_Of (Entity (Bound), Loc));
4203 Analyze (Ref);
4204 Resolve (Ref, Typ);
4205 return Ref;
4206 end if;
4207 end Actual_Discriminant_Ref;
4209 -- Start of processing for Actual_Index_Type
4211 begin
4212 if not Has_Discriminants (Tsk)
4213 or else (not Is_Entity_Name (Lo)
4214 and then not Is_Entity_Name (Hi))
4215 then
4216 return Entry_Index_Type (E);
4218 else
4219 New_T := Create_Itype (Ekind (Typ), Parent (Entry_Name));
4220 Set_Etype (New_T, Base_Type (Typ));
4221 Set_Size_Info (New_T, Typ);
4222 Set_RM_Size (New_T, RM_Size (Typ));
4223 Set_Scalar_Range (New_T,
4224 Make_Range (Sloc (Entry_Name),
4225 Low_Bound => Actual_Discriminant_Ref (Lo),
4226 High_Bound => Actual_Discriminant_Ref (Hi)));
4228 return New_T;
4229 end if;
4230 end Actual_Index_Type;
4232 -- Start of processing of Resolve_Entry
4234 begin
4235 -- Find name of entry being called, and resolve prefix of name
4236 -- with its own type. The prefix can be overloaded, and the name
4237 -- and signature of the entry must be taken into account.
4239 if Nkind (Entry_Name) = N_Indexed_Component then
4241 -- Case of dealing with entry family within the current tasks
4243 E_Name := Prefix (Entry_Name);
4245 else
4246 E_Name := Entry_Name;
4247 end if;
4249 if Is_Entity_Name (E_Name) then
4250 -- Entry call to an entry (or entry family) in the current task.
4251 -- This is legal even though the task will deadlock. Rewrite as
4252 -- call to current task.
4254 -- This can also be a call to an entry in an enclosing task.
4255 -- If this is a single task, we have to retrieve its name,
4256 -- because the scope of the entry is the task type, not the
4257 -- object. If the enclosing task is a task type, the identity
4258 -- of the task is given by its own self variable.
4260 -- Finally this can be a requeue on an entry of the same task
4261 -- or protected object.
4263 S := Scope (Entity (E_Name));
4265 for J in reverse 0 .. Scope_Stack.Last loop
4267 if Is_Task_Type (Scope_Stack.Table (J).Entity)
4268 and then not Comes_From_Source (S)
4269 then
4270 -- S is an enclosing task or protected object. The concurrent
4271 -- declaration has been converted into a type declaration, and
4272 -- the object itself has an object declaration that follows
4273 -- the type in the same declarative part.
4275 Tsk := Next_Entity (S);
4277 while Etype (Tsk) /= S loop
4278 Next_Entity (Tsk);
4279 end loop;
4281 S := Tsk;
4282 exit;
4284 elsif S = Scope_Stack.Table (J).Entity then
4286 -- Call to current task. Will be transformed into call to Self
4288 exit;
4290 end if;
4291 end loop;
4293 New_N :=
4294 Make_Selected_Component (Loc,
4295 Prefix => New_Occurrence_Of (S, Loc),
4296 Selector_Name =>
4297 New_Occurrence_Of (Entity (E_Name), Loc));
4298 Rewrite (E_Name, New_N);
4299 Analyze (E_Name);
4301 elsif Nkind (Entry_Name) = N_Selected_Component
4302 and then Is_Overloaded (Prefix (Entry_Name))
4303 then
4304 -- Use the entry name (which must be unique at this point) to
4305 -- find the prefix that returns the corresponding task type or
4306 -- protected type.
4308 declare
4309 Pref : constant Node_Id := Prefix (Entry_Name);
4310 Ent : constant Entity_Id := Entity (Selector_Name (Entry_Name));
4311 I : Interp_Index;
4312 It : Interp;
4314 begin
4315 Get_First_Interp (Pref, I, It);
4317 while Present (It.Typ) loop
4319 if Scope (Ent) = It.Typ then
4320 Set_Etype (Pref, It.Typ);
4321 exit;
4322 end if;
4324 Get_Next_Interp (I, It);
4325 end loop;
4326 end;
4327 end if;
4329 if Nkind (Entry_Name) = N_Selected_Component then
4330 Resolve (Prefix (Entry_Name));
4332 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
4333 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
4334 Resolve (Prefix (Prefix (Entry_Name)));
4335 Index := First (Expressions (Entry_Name));
4336 Resolve (Index, Entry_Index_Type (Nam));
4338 -- Up to this point the expression could have been the actual
4339 -- in a simple entry call, and be given by a named association.
4341 if Nkind (Index) = N_Parameter_Association then
4343 else
4344 Apply_Range_Check (Index, Actual_Index_Type (Nam));
4345 end if;
4346 end if;
4347 end Resolve_Entry;
4349 ------------------------
4350 -- Resolve_Entry_Call --
4351 ------------------------
4353 procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id) is
4354 Entry_Name : constant Node_Id := Name (N);
4355 Loc : constant Source_Ptr := Sloc (Entry_Name);
4356 Actuals : List_Id;
4357 First_Named : Node_Id;
4358 Nam : Entity_Id;
4359 Norm_OK : Boolean;
4360 Obj : Node_Id;
4361 Was_Over : Boolean;
4363 begin
4364 -- We kill all checks here, because it does not seem worth the
4365 -- effort to do anything better, an entry call is a big operation.
4367 Kill_All_Checks;
4369 -- Processing of the name is similar for entry calls and protected
4370 -- operation calls. Once the entity is determined, we can complete
4371 -- the resolution of the actuals.
4373 -- The selector may be overloaded, in the case of a protected object
4374 -- with overloaded functions. The type of the context is used for
4375 -- resolution.
4377 if Nkind (Entry_Name) = N_Selected_Component
4378 and then Is_Overloaded (Selector_Name (Entry_Name))
4379 and then Typ /= Standard_Void_Type
4380 then
4381 declare
4382 I : Interp_Index;
4383 It : Interp;
4385 begin
4386 Get_First_Interp (Selector_Name (Entry_Name), I, It);
4388 while Present (It.Typ) loop
4390 if Covers (Typ, It.Typ) then
4391 Set_Entity (Selector_Name (Entry_Name), It.Nam);
4392 Set_Etype (Entry_Name, It.Typ);
4394 Generate_Reference (It.Typ, N, ' ');
4395 end if;
4397 Get_Next_Interp (I, It);
4398 end loop;
4399 end;
4400 end if;
4402 Resolve_Entry (Entry_Name);
4404 if Nkind (Entry_Name) = N_Selected_Component then
4406 -- Simple entry call.
4408 Nam := Entity (Selector_Name (Entry_Name));
4409 Obj := Prefix (Entry_Name);
4410 Was_Over := Is_Overloaded (Selector_Name (Entry_Name));
4412 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
4414 -- Call to member of entry family.
4416 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
4417 Obj := Prefix (Prefix (Entry_Name));
4418 Was_Over := Is_Overloaded (Selector_Name (Prefix (Entry_Name)));
4419 end if;
4421 -- We cannot in general check the maximum depth of protected entry
4422 -- calls at compile time. But we can tell that any protected entry
4423 -- call at all violates a specified nesting depth of zero.
4425 if Is_Protected_Type (Scope (Nam)) then
4426 Check_Restriction (Max_Entry_Queue_Depth, N);
4427 end if;
4429 -- Use context type to disambiguate a protected function that can be
4430 -- called without actuals and that returns an array type, and where
4431 -- the argument list may be an indexing of the returned value.
4433 if Ekind (Nam) = E_Function
4434 and then Needs_No_Actuals (Nam)
4435 and then Present (Parameter_Associations (N))
4436 and then
4437 ((Is_Array_Type (Etype (Nam))
4438 and then Covers (Typ, Component_Type (Etype (Nam))))
4440 or else (Is_Access_Type (Etype (Nam))
4441 and then Is_Array_Type (Designated_Type (Etype (Nam)))
4442 and then Covers (Typ,
4443 Component_Type (Designated_Type (Etype (Nam))))))
4444 then
4445 declare
4446 Index_Node : Node_Id;
4448 begin
4449 Index_Node :=
4450 Make_Indexed_Component (Loc,
4451 Prefix =>
4452 Make_Function_Call (Loc,
4453 Name => Relocate_Node (Entry_Name)),
4454 Expressions => Parameter_Associations (N));
4456 -- Since we are correcting a node classification error made by
4457 -- the parser, we call Replace rather than Rewrite.
4459 Replace (N, Index_Node);
4460 Set_Etype (Prefix (N), Etype (Nam));
4461 Set_Etype (N, Typ);
4462 Resolve_Indexed_Component (N, Typ);
4463 return;
4464 end;
4465 end if;
4467 -- The operation name may have been overloaded. Order the actuals
4468 -- according to the formals of the resolved entity, and set the
4469 -- return type to that of the operation.
4471 if Was_Over then
4472 Normalize_Actuals (N, Nam, False, Norm_OK);
4473 pragma Assert (Norm_OK);
4474 Set_Etype (N, Etype (Nam));
4475 end if;
4477 Resolve_Actuals (N, Nam);
4478 Generate_Reference (Nam, Entry_Name);
4480 if Ekind (Nam) = E_Entry
4481 or else Ekind (Nam) = E_Entry_Family
4482 then
4483 Check_Potentially_Blocking_Operation (N);
4484 end if;
4486 -- Verify that a procedure call cannot masquerade as an entry
4487 -- call where an entry call is expected.
4489 if Ekind (Nam) = E_Procedure then
4490 if Nkind (Parent (N)) = N_Entry_Call_Alternative
4491 and then N = Entry_Call_Statement (Parent (N))
4492 then
4495 elsif Nkind (Parent (N)) = N_Triggering_Alternative
4496 and then N = Triggering_Statement (Parent (N))
4497 then
4500 elsif Ekind (Scope (Nam)) = E_Task_Type
4501 and then not In_Open_Scopes (Scope (Nam))
4502 then
4504 end if;
4505 end if;
4507 -- After resolution, entry calls and protected procedure calls
4508 -- are changed into entry calls, for expansion. The structure
4509 -- of the node does not change, so it can safely be done in place.
4510 -- Protected function calls must keep their structure because they
4511 -- are subexpressions.
4513 if Ekind (Nam) /= E_Function then
4515 -- A protected operation that is not a function may modify the
4516 -- corresponding object, and cannot apply to a constant.
4517 -- If this is an internal call, the prefix is the type itself.
4519 if Is_Protected_Type (Scope (Nam))
4520 and then not Is_Variable (Obj)
4521 and then (not Is_Entity_Name (Obj)
4522 or else not Is_Type (Entity (Obj)))
4523 then
4524 Error_Msg_N
4526 Entry_Name);
4527 end if;
4529 Actuals := Parameter_Associations (N);
4530 First_Named := First_Named_Actual (N);
4532 Rewrite (N,
4533 Make_Entry_Call_Statement (Loc,
4534 Name => Entry_Name,
4535 Parameter_Associations => Actuals));
4537 Set_First_Named_Actual (N, First_Named);
4538 Set_Analyzed (N, True);
4540 -- Protected functions can return on the secondary stack, in which
4541 -- case we must trigger the transient scope mechanism
4543 elsif Expander_Active
4544 and then Requires_Transient_Scope (Etype (Nam))
4545 then
4546 Establish_Transient_Scope (N,
4547 Sec_Stack => not Functions_Return_By_DSP_On_Target);
4548 end if;
4549 end Resolve_Entry_Call;
4551 -------------------------
4552 -- Resolve_Equality_Op --
4553 -------------------------
4555 -- Both arguments must have the same type, and the boolean context
4556 -- does not participate in the resolution. The first pass verifies
4557 -- that the interpretation is not ambiguous, and the type of the left
4558 -- argument is correctly set, or is Any_Type in case of ambiguity.
4559 -- If both arguments are strings or aggregates, allocators, or Null,
4560 -- they are ambiguous even though they carry a single (universal) type.
4561 -- Diagnose this case here.
4563 procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id) is
4564 L : constant Node_Id := Left_Opnd (N);
4565 R : constant Node_Id := Right_Opnd (N);
4566 T : Entity_Id := Find_Unique_Type (L, R);
4568 function Find_Unique_Access_Type return Entity_Id;
4569 -- In the case of allocators, make a last-ditch attempt to find a single
4570 -- access type with the right designated type. This is semantically
4571 -- dubious, and of no interest to any real code, but c48008a makes it
4572 -- all worthwhile.
4574 -----------------------------
4575 -- Find_Unique_Access_Type --
4576 -----------------------------
4578 function Find_Unique_Access_Type return Entity_Id is
4579 Acc : Entity_Id;
4580 E : Entity_Id;
4581 S : Entity_Id := Current_Scope;
4583 begin
4584 if Ekind (Etype (R)) = E_Allocator_Type then
4585 Acc := Designated_Type (Etype (R));
4587 elsif Ekind (Etype (L)) = E_Allocator_Type then
4588 Acc := Designated_Type (Etype (L));
4590 else
4591 return Empty;
4592 end if;
4594 while S /= Standard_Standard loop
4595 E := First_Entity (S);
4597 while Present (E) loop
4599 if Is_Type (E)
4600 and then Is_Access_Type (E)
4601 and then Ekind (E) /= E_Allocator_Type
4602 and then Designated_Type (E) = Base_Type (Acc)
4603 then
4604 return E;
4605 end if;
4607 Next_Entity (E);
4608 end loop;
4610 S := Scope (S);
4611 end loop;
4613 return Empty;
4614 end Find_Unique_Access_Type;
4616 -- Start of processing for Resolve_Equality_Op
4618 begin
4619 Check_Direct_Boolean_Op (N);
4621 Set_Etype (N, Base_Type (Typ));
4622 Generate_Reference (T, N, ' ');
4624 if T = Any_Fixed then
4625 T := Unique_Fixed_Point_Type (L);
4626 end if;
4628 if T /= Any_Type then
4630 if T = Any_String
4631 or else T = Any_Composite
4632 or else T = Any_Character
4633 then
4635 if T = Any_Character then
4636 Ambiguous_Character (L);
4637 else
4639 end if;
4641 Set_Etype (N, Any_Type);
4642 return;
4644 elsif T = Any_Access
4645 or else Ekind (T) = E_Allocator_Type
4646 then
4647 T := Find_Unique_Access_Type;
4649 if No (T) then
4651 Set_Etype (N, Any_Type);
4652 return;
4653 end if;
4654 end if;
4656 if Comes_From_Source (N)
4657 and then Has_Unchecked_Union (T)
4658 then
4659 Error_Msg_N
4661 end if;
4663 Resolve (L, T);
4664 Resolve (R, T);
4666 if Warn_On_Redundant_Constructs
4667 and then Comes_From_Source (N)
4668 and then Is_Entity_Name (R)
4669 and then Entity (R) = Standard_True
4670 and then Comes_From_Source (R)
4671 then
4673 end if;
4675 Check_Unset_Reference (L);
4676 Check_Unset_Reference (R);
4677 Generate_Operator_Reference (N, T);
4679 -- If this is an inequality, it may be the implicit inequality
4680 -- created for a user-defined operation, in which case the corres-
4681 -- ponding equality operation is not intrinsic, and the operation
4682 -- cannot be constant-folded. Else fold.
4684 if Nkind (N) = N_Op_Eq
4685 or else Comes_From_Source (Entity (N))
4686 or else Ekind (Entity (N)) = E_Operator
4687 or else Is_Intrinsic_Subprogram
4688 (Corresponding_Equality (Entity (N)))
4689 then
4690 Eval_Relational_Op (N);
4691 elsif Nkind (N) = N_Op_Ne
4692 and then Is_Abstract (Entity (N))
4693 then
4695 end if;
4696 end if;
4697 end Resolve_Equality_Op;
4699 ----------------------------------
4700 -- Resolve_Explicit_Dereference --
4701 ----------------------------------
4703 procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id) is
4704 P : constant Node_Id := Prefix (N);
4705 I : Interp_Index;
4706 It : Interp;
4708 begin
4709 -- Now that we know the type, check that this is not a
4710 -- dereference of an uncompleted type. Note that this
4711 -- is not entirely correct, because dereferences of
4712 -- private types are legal in default expressions.
4713 -- This consideration also applies to similar checks
4714 -- for allocators, qualified expressions, and type
4715 -- conversions. ???
4717 Check_Fully_Declared (Typ, N);
4719 if Is_Overloaded (P) then
4721 -- Use the context type to select the prefix that has the
4722 -- correct designated type.
4724 Get_First_Interp (P, I, It);
4725 while Present (It.Typ) loop
4726 exit when Is_Access_Type (It.Typ)
4727 and then Covers (Typ, Designated_Type (It.Typ));
4729 Get_Next_Interp (I, It);
4730 end loop;
4732 Resolve (P, It.Typ);
4733 Set_Etype (N, Designated_Type (It.Typ));
4735 else
4736 Resolve (P);
4737 end if;
4739 if Is_Access_Type (Etype (P)) then
4740 Apply_Access_Check (N);
4741 end if;
4743 -- If the designated type is a packed unconstrained array type,
4744 -- and the explicit dereference is not in the context of an
4745 -- attribute reference, then we must compute and set the actual
4746 -- subtype, since it is needed by Gigi. The reason we exclude
4747 -- the attribute case is that this is handled fine by Gigi, and
4748 -- in fact we use such attributes to build the actual subtype.
4749 -- We also exclude generated code (which builds actual subtypes
4750 -- directly if they are needed).
4752 if Is_Array_Type (Etype (N))
4753 and then Is_Packed (Etype (N))
4754 and then not Is_Constrained (Etype (N))
4755 and then Nkind (Parent (N)) /= N_Attribute_Reference
4756 and then Comes_From_Source (N)
4757 then
4758 Set_Etype (N, Get_Actual_Subtype (N));
4759 end if;
4761 -- Note: there is no Eval processing required for an explicit
4762 -- deference, because the type is known to be an allocators, and
4763 -- allocator expressions can never be static.
4765 end Resolve_Explicit_Dereference;
4767 -------------------------------
4768 -- Resolve_Indexed_Component --
4769 -------------------------------
4771 procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id) is
4772 Name : constant Node_Id := Prefix (N);
4773 Expr : Node_Id;
4774 Array_Type : Entity_Id := Empty; -- to prevent junk warning
4775 Index : Node_Id;
4777 begin
4778 if Is_Overloaded (Name) then
4780 -- Use the context type to select the prefix that yields the
4781 -- correct component type.
4783 declare
4784 I : Interp_Index;
4785 It : Interp;
4786 I1 : Interp_Index := 0;
4787 P : constant Node_Id := Prefix (N);
4788 Found : Boolean := False;
4790 begin
4791 Get_First_Interp (P, I, It);
4793 while Present (It.Typ) loop
4795 if (Is_Array_Type (It.Typ)
4796 and then Covers (Typ, Component_Type (It.Typ)))
4797 or else (Is_Access_Type (It.Typ)
4798 and then Is_Array_Type (Designated_Type (It.Typ))
4799 and then Covers
4800 (Typ, Component_Type (Designated_Type (It.Typ))))
4801 then
4802 if Found then
4803 It := Disambiguate (P, I1, I, Any_Type);
4805 if It = No_Interp then
4807 Set_Etype (N, Typ);
4808 return;
4810 else
4811 Found := True;
4812 Array_Type := It.Typ;
4813 I1 := I;
4814 end if;
4816 else
4817 Found := True;
4818 Array_Type := It.Typ;
4819 I1 := I;
4820 end if;
4821 end if;
4823 Get_Next_Interp (I, It);
4824 end loop;
4825 end;
4827 else
4828 Array_Type := Etype (Name);
4829 end if;
4831 Resolve (Name, Array_Type);
4832 Array_Type := Get_Actual_Subtype_If_Available (Name);
4834 -- If prefix is access type, dereference to get real array type.
4835 -- Note: we do not apply an access check because the expander always
4836 -- introduces an explicit dereference, and the check will happen there.
4838 if Is_Access_Type (Array_Type) then
4839 Array_Type := Designated_Type (Array_Type);
4840 end if;
4842 -- If name was overloaded, set component type correctly now.
4844 Set_Etype (N, Component_Type (Array_Type));
4846 Index := First_Index (Array_Type);
4847 Expr := First (Expressions (N));
4849 -- The prefix may have resolved to a string literal, in which case
4850 -- its etype has a special representation. This is only possible
4851 -- currently if the prefix is a static concatenation, written in
4852 -- functional notation.
4854 if Ekind (Array_Type) = E_String_Literal_Subtype then
4855 Resolve (Expr, Standard_Positive);
4857 else
4858 while Present (Index) and Present (Expr) loop
4859 Resolve (Expr, Etype (Index));
4860 Check_Unset_Reference (Expr);
4862 if Is_Scalar_Type (Etype (Expr)) then
4863 Apply_Scalar_Range_Check (Expr, Etype (Index));
4864 else
4865 Apply_Range_Check (Expr, Get_Actual_Subtype (Index));
4866 end if;
4868 Next_Index (Index);
4869 Next (Expr);
4870 end loop;
4871 end if;
4873 Eval_Indexed_Component (N);
4874 end Resolve_Indexed_Component;
4876 -----------------------------
4877 -- Resolve_Integer_Literal --
4878 -----------------------------
4880 procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id) is
4881 begin
4882 Set_Etype (N, Typ);
4883 Eval_Integer_Literal (N);
4884 end Resolve_Integer_Literal;
4886 ---------------------------------
4887 -- Resolve_Intrinsic_Operator --
4888 ---------------------------------
4890 procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id) is
4891 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
4892 Op : Entity_Id;
4893 Arg1 : Node_Id;
4894 Arg2 : Node_Id;
4896 begin
4897 Op := Entity (N);
4899 while Scope (Op) /= Standard_Standard loop
4900 Op := Homonym (Op);
4901 pragma Assert (Present (Op));
4902 end loop;
4904 Set_Entity (N, Op);
4906 -- If the operand type is private, rewrite with suitable
4907 -- conversions on the operands and the result, to expose
4908 -- the proper underlying numeric type.
4910 if Is_Private_Type (Typ) then
4911 Arg1 := Unchecked_Convert_To (Btyp, Left_Opnd (N));
4913 if Nkind (N) = N_Op_Expon then
4914 Arg2 := Unchecked_Convert_To (Standard_Integer, Right_Opnd (N));
4915 else
4916 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
4917 end if;
4919 Save_Interps (Left_Opnd (N), Expression (Arg1));
4920 Save_Interps (Right_Opnd (N), Expression (Arg2));
4922 Set_Left_Opnd (N, Arg1);
4923 Set_Right_Opnd (N, Arg2);
4925 Set_Etype (N, Btyp);
4926 Rewrite (N, Unchecked_Convert_To (Typ, N));
4927 Resolve (N, Typ);
4929 elsif Typ /= Etype (Left_Opnd (N))
4930 or else Typ /= Etype (Right_Opnd (N))
4931 then
4932 -- Add explicit conversion where needed, and save interpretations
4933 -- if operands are overloaded.
4935 Arg1 := Convert_To (Typ, Left_Opnd (N));
4936 Arg2 := Convert_To (Typ, Right_Opnd (N));
4938 if Nkind (Arg1) = N_Type_Conversion then
4939 Save_Interps (Left_Opnd (N), Expression (Arg1));
4940 end if;
4942 if Nkind (Arg2) = N_Type_Conversion then
4943 Save_Interps (Right_Opnd (N), Expression (Arg2));
4944 end if;
4946 Rewrite (Left_Opnd (N), Arg1);
4947 Rewrite (Right_Opnd (N), Arg2);
4948 Analyze (Arg1);
4949 Analyze (Arg2);
4950 Resolve_Arithmetic_Op (N, Typ);
4952 else
4953 Resolve_Arithmetic_Op (N, Typ);
4954 end if;
4955 end Resolve_Intrinsic_Operator;
4957 --------------------------------------
4958 -- Resolve_Intrinsic_Unary_Operator --
4959 --------------------------------------
4961 procedure Resolve_Intrinsic_Unary_Operator
4962 (N : Node_Id;
4963 Typ : Entity_Id)
4964 is
4965 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
4966 Op : Entity_Id;
4967 Arg2 : Node_Id;
4969 begin
4970 Op := Entity (N);
4972 while Scope (Op) /= Standard_Standard loop
4973 Op := Homonym (Op);
4974 pragma Assert (Present (Op));
4975 end loop;
4977 Set_Entity (N, Op);
4979 if Is_Private_Type (Typ) then
4980 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
4981 Save_Interps (Right_Opnd (N), Expression (Arg2));
4983 Set_Right_Opnd (N, Arg2);
4985 Set_Etype (N, Btyp);
4986 Rewrite (N, Unchecked_Convert_To (Typ, N));
4987 Resolve (N, Typ);
4989 else
4990 Resolve_Unary_Op (N, Typ);
4991 end if;
4992 end Resolve_Intrinsic_Unary_Operator;
4994 ------------------------
4995 -- Resolve_Logical_Op --
4996 ------------------------
4998 procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id) is
4999 B_Typ : Entity_Id;
5001 begin
5002 Check_Direct_Boolean_Op (N);
5004 -- Predefined operations on scalar types yield the base type. On
5005 -- the other hand, logical operations on arrays yield the type of
5006 -- the arguments (and the context).
5008 if Is_Array_Type (Typ) then
5009 B_Typ := Typ;
5010 else
5011 B_Typ := Base_Type (Typ);
5012 end if;
5014 -- The following test is required because the operands of the operation
5015 -- may be literals, in which case the resulting type appears to be
5016 -- compatible with a signed integer type, when in fact it is compatible
5017 -- only with modular types. If the context itself is universal, the
5018 -- operation is illegal.
5020 if not Valid_Boolean_Arg (Typ) then
5022 Set_Etype (N, Any_Type);
5023 return;
5025 elsif Typ = Any_Modular then
5026 Error_Msg_N
5028 Set_Etype (N, Any_Type);
5029 return;
5030 elsif Is_Modular_Integer_Type (Typ)
5031 and then Etype (Left_Opnd (N)) = Universal_Integer
5032 and then Etype (Right_Opnd (N)) = Universal_Integer
5033 then
5034 Check_For_Visible_Operator (N, B_Typ);
5035 end if;
5037 Resolve (Left_Opnd (N), B_Typ);
5038 Resolve (Right_Opnd (N), B_Typ);
5040 Check_Unset_Reference (Left_Opnd (N));
5041 Check_Unset_Reference (Right_Opnd (N));
5043 Set_Etype (N, B_Typ);
5044 Generate_Operator_Reference (N, B_Typ);
5045 Eval_Logical_Op (N);
5046 end Resolve_Logical_Op;
5048 ---------------------------
5049 -- Resolve_Membership_Op --
5050 ---------------------------
5052 -- The context can only be a boolean type, and does not determine
5053 -- the arguments. Arguments should be unambiguous, but the preference
5054 -- rule for universal types applies.
5056 procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id) is
5057 pragma Warnings (Off, Typ);
5059 L : constant Node_Id := Left_Opnd (N);
5060 R : constant Node_Id := Right_Opnd (N);
5061 T : Entity_Id;
5063 begin
5064 if L = Error or else R = Error then
5065 return;
5066 end if;
5068 if not Is_Overloaded (R)
5069 and then
5070 (Etype (R) = Universal_Integer or else
5071 Etype (R) = Universal_Real)
5072 and then Is_Overloaded (L)
5073 then
5074 T := Etype (R);
5075 else
5076 T := Intersect_Types (L, R);
5077 end if;
5079 Resolve (L, T);
5080 Check_Unset_Reference (L);
5082 if Nkind (R) = N_Range
5083 and then not Is_Scalar_Type (T)
5084 then
5086 end if;
5088 if Is_Entity_Name (R) then
5089 Freeze_Expression (R);
5090 else
5091 Resolve (R, T);
5092 Check_Unset_Reference (R);
5093 end if;
5095 Eval_Membership_Op (N);
5096 end Resolve_Membership_Op;
5098 ------------------
5099 -- Resolve_Null --
5100 ------------------
5102 procedure Resolve_Null (N : Node_Id; Typ : Entity_Id) is
5103 begin
5104 -- For now allow circumvention of the restriction against
5105 -- anonymous null access values via a debug switch to allow
5106 -- for easier transition.
5108 if not Debug_Flag_J
5109 and then Ekind (Typ) = E_Anonymous_Access_Type
5110 and then Comes_From_Source (N)
5111 then
5112 -- In the common case of a call which uses an explicitly null
5113 -- value for an access parameter, give specialized error msg
5115 if Nkind (Parent (N)) = N_Procedure_Call_Statement
5116 or else
5117 Nkind (Parent (N)) = N_Function_Call
5118 then
5119 Error_Msg_N
5122 -- Standard message for all other cases (are there any?)
5124 else
5125 Error_Msg_N
5127 end if;
5128 end if;
5130 -- In a distributed context, null for a remote access to subprogram
5131 -- may need to be replaced with a special record aggregate. In this
5132 -- case, return after having done the transformation.
5134 if (Ekind (Typ) = E_Record_Type
5135 or else Is_Remote_Access_To_Subprogram_Type (Typ))
5136 and then Remote_AST_Null_Value (N, Typ)
5137 then
5138 return;
5139 end if;
5141 -- The null literal takes its type from the context.
5143 Set_Etype (N, Typ);
5144 end Resolve_Null;
5146 -----------------------
5147 -- Resolve_Op_Concat --
5148 -----------------------
5150 procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id) is
5151 Btyp : constant Entity_Id := Base_Type (Typ);
5152 Op1 : constant Node_Id := Left_Opnd (N);
5153 Op2 : constant Node_Id := Right_Opnd (N);
5155 procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean);
5156 -- Internal procedure to resolve one operand of concatenation operator.
5157 -- The operand is either of the array type or of the component type.
5158 -- If the operand is an aggregate, and the component type is composite,
5159 -- this is ambiguous if component type has aggregates.
5161 -------------------------------
5162 -- Resolve_Concatenation_Arg --
5163 -------------------------------
5165 procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean) is
5166 begin
5167 if In_Instance then
5168 if Is_Comp
5169 or else (not Is_Overloaded (Arg)
5170 and then Etype (Arg) /= Any_Composite
5171 and then Covers (Component_Type (Typ), Etype (Arg)))
5172 then
5173 Resolve (Arg, Component_Type (Typ));
5174 else
5175 Resolve (Arg, Btyp);
5176 end if;
5178 elsif Has_Compatible_Type (Arg, Component_Type (Typ)) then
5180 if Nkind (Arg) = N_Aggregate
5181 and then Is_Composite_Type (Component_Type (Typ))
5182 then
5183 if Is_Private_Type (Component_Type (Typ)) then
5184 Resolve (Arg, Btyp);
5186 else
5188 Set_Etype (Arg, Any_Type);
5189 end if;
5191 else
5192 if Is_Overloaded (Arg)
5193 and then Has_Compatible_Type (Arg, Typ)
5194 and then Etype (Arg) /= Any_Type
5195 then
5198 declare
5199 I : Interp_Index;
5200 It : Interp;
5202 begin
5203 Get_First_Interp (Arg, I, It);
5205 while Present (It.Nam) loop
5207 if Base_Type (Etype (It.Nam)) = Base_Type (Typ)
5208 or else Base_Type (Etype (It.Nam)) =
5209 Base_Type (Component_Type (Typ))
5210 then
5211 Error_Msg_Sloc := Sloc (It.Nam);
5213 end if;
5215 Get_Next_Interp (I, It);
5216 end loop;
5217 end;
5218 end if;
5220 Resolve (Arg, Component_Type (Typ));
5222 if Nkind (Arg) = N_String_Literal then
5223 Set_Etype (Arg, Component_Type (Typ));
5224 end if;
5226 if Arg = Left_Opnd (N) then
5227 Set_Is_Component_Left_Opnd (N);
5228 else
5229 Set_Is_Component_Right_Opnd (N);
5230 end if;
5231 end if;
5233 else
5234 Resolve (Arg, Btyp);
5235 end if;
5237 Check_Unset_Reference (Arg);
5238 end Resolve_Concatenation_Arg;
5240 -- Start of processing for Resolve_Op_Concat
5242 begin
5243 Set_Etype (N, Btyp);
5245 if Is_Limited_Composite (Btyp) then
5247 Explain_Limited_Type (Btyp, N);
5248 end if;
5250 -- If the operands are themselves concatenations, resolve them as
5251 -- such directly. This removes several layers of recursion and allows
5252 -- GNAT to handle larger multiple concatenations.
5254 if Nkind (Op1) = N_Op_Concat
5255 and then not Is_Array_Type (Component_Type (Typ))
5256 and then Entity (Op1) = Entity (N)
5257 then
5258 Resolve_Op_Concat (Op1, Typ);
5259 else
5260 Resolve_Concatenation_Arg
5261 (Op1, Is_Component_Left_Opnd (N));
5262 end if;
5264 if Nkind (Op2) = N_Op_Concat
5265 and then not Is_Array_Type (Component_Type (Typ))
5266 and then Entity (Op2) = Entity (N)
5267 then
5268 Resolve_Op_Concat (Op2, Typ);
5269 else
5270 Resolve_Concatenation_Arg
5271 (Op2, Is_Component_Right_Opnd (N));
5272 end if;
5274 Generate_Operator_Reference (N, Typ);
5276 if Is_String_Type (Typ) then
5277 Eval_Concatenation (N);
5278 end if;
5280 -- If this is not a static concatenation, but the result is a
5281 -- string type (and not an array of strings) insure that static
5282 -- string operands have their subtypes properly constructed.
5284 if Nkind (N) /= N_String_Literal
5285 and then Is_Character_Type (Component_Type (Typ))
5286 then
5287 Set_String_Literal_Subtype (Op1, Typ);
5288 Set_String_Literal_Subtype (Op2, Typ);
5289 end if;
5290 end Resolve_Op_Concat;
5292 ----------------------
5293 -- Resolve_Op_Expon --
5294 ----------------------
5296 procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id) is
5297 B_Typ : constant Entity_Id := Base_Type (Typ);
5299 begin
5300 -- Catch attempts to do fixed-point exponentation with universal
5301 -- operands, which is a case where the illegality is not caught
5302 -- during normal operator analysis.
5304 if Is_Fixed_Point_Type (Typ) and then Comes_From_Source (N) then
5306 return;
5307 end if;
5309 if Comes_From_Source (N)
5310 and then Ekind (Entity (N)) = E_Function
5311 and then Is_Imported (Entity (N))
5312 and then Is_Intrinsic_Subprogram (Entity (N))
5313 then
5314 Resolve_Intrinsic_Operator (N, Typ);
5315 return;
5316 end if;
5318 if Etype (Left_Opnd (N)) = Universal_Integer
5319 or else Etype (Left_Opnd (N)) = Universal_Real
5320 then
5321 Check_For_Visible_Operator (N, B_Typ);
5322 end if;
5324 -- We do the resolution using the base type, because intermediate values
5325 -- in expressions always are of the base type, not a subtype of it.
5327 Resolve (Left_Opnd (N), B_Typ);
5328 Resolve (Right_Opnd (N), Standard_Integer);
5330 Check_Unset_Reference (Left_Opnd (N));
5331 Check_Unset_Reference (Right_Opnd (N));
5333 Set_Etype (N, B_Typ);
5334 Generate_Operator_Reference (N, B_Typ);
5335 Eval_Op_Expon (N);
5337 -- Set overflow checking bit. Much cleverer code needed here eventually
5338 -- and perhaps the Resolve routines should be separated for the various
5339 -- arithmetic operations, since they will need different processing. ???
5341 if Nkind (N) in N_Op then
5342 if not Overflow_Checks_Suppressed (Etype (N)) then
5343 Enable_Overflow_Check (N);
5344 end if;
5345 end if;
5346 end Resolve_Op_Expon;
5348 --------------------
5349 -- Resolve_Op_Not --
5350 --------------------
5352 procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id) is
5353 B_Typ : Entity_Id;
5355 function Parent_Is_Boolean return Boolean;
5356 -- This function determines if the parent node is a boolean operator
5357 -- or operation (comparison op, membership test, or short circuit form)
5358 -- and the not in question is the left operand of this operation.
5359 -- Note that if the not is in parens, then false is returned.
5361 function Parent_Is_Boolean return Boolean is
5362 begin
5363 if Paren_Count (N) /= 0 then
5364 return False;
5366 else
5367 case Nkind (Parent (N)) is
5368 when N_Op_And |
5369 N_Op_Eq |
5370 N_Op_Ge |
5371 N_Op_Gt |
5372 N_Op_Le |
5373 N_Op_Lt |
5374 N_Op_Ne |
5375 N_Op_Or |
5376 N_Op_Xor |
5377 N_In |
5378 N_Not_In |
5379 N_And_Then |
5380 N_Or_Else =>
5382 return Left_Opnd (Parent (N)) = N;
5384 when others =>
5385 return False;
5386 end case;
5387 end if;
5388 end Parent_Is_Boolean;
5390 -- Start of processing for Resolve_Op_Not
5392 begin
5393 -- Predefined operations on scalar types yield the base type. On
5394 -- the other hand, logical operations on arrays yield the type of
5395 -- the arguments (and the context).
5397 if Is_Array_Type (Typ) then
5398 B_Typ := Typ;
5399 else
5400 B_Typ := Base_Type (Typ);
5401 end if;
5403 if not Valid_Boolean_Arg (Typ) then
5405 Set_Etype (N, Any_Type);
5406 return;
5408 elsif Typ = Universal_Integer or else Typ = Any_Modular then
5409 if Parent_Is_Boolean then
5410 Error_Msg_N
5412 Right_Opnd (N));
5413 else
5414 Error_Msg_N
5416 end if;
5418 Set_Etype (N, Any_Type);
5419 return;
5421 else
5422 if not Is_Boolean_Type (Typ)
5423 and then Parent_Is_Boolean
5424 then
5426 end if;
5428 Resolve (Right_Opnd (N), B_Typ);
5429 Check_Unset_Reference (Right_Opnd (N));
5430 Set_Etype (N, B_Typ);
5431 Generate_Operator_Reference (N, B_Typ);
5432 Eval_Op_Not (N);
5433 end if;
5434 end Resolve_Op_Not;
5436 -----------------------------
5437 -- Resolve_Operator_Symbol --
5438 -----------------------------
5440 -- Nothing to be done, all resolved already
5442 procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id) is
5443 pragma Warnings (Off, N);
5444 pragma Warnings (Off, Typ);
5446 begin
5447 null;
5448 end Resolve_Operator_Symbol;
5450 ----------------------------------
5451 -- Resolve_Qualified_Expression --
5452 ----------------------------------
5454 procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id) is
5455 pragma Warnings (Off, Typ);
5457 Target_Typ : constant Entity_Id := Entity (Subtype_Mark (N));
5458 Expr : constant Node_Id := Expression (N);
5460 begin
5461 Resolve (Expr, Target_Typ);
5463 -- A qualified expression requires an exact match of the type,
5464 -- class-wide matching is not allowed.
5466 if Is_Class_Wide_Type (Target_Typ)
5467 and then Base_Type (Etype (Expr)) /= Base_Type (Target_Typ)
5468 then
5469 Wrong_Type (Expr, Target_Typ);
5470 end if;
5472 -- If the target type is unconstrained, then we reset the type of
5473 -- the result from the type of the expression. For other cases, the
5474 -- actual subtype of the expression is the target type.
5476 if Is_Composite_Type (Target_Typ)
5477 and then not Is_Constrained (Target_Typ)
5478 then
5479 Set_Etype (N, Etype (Expr));
5480 end if;
5482 Eval_Qualified_Expression (N);
5483 end Resolve_Qualified_Expression;
5485 -------------------
5486 -- Resolve_Range --
5487 -------------------
5489 procedure Resolve_Range (N : Node_Id; Typ : Entity_Id) is
5490 L : constant Node_Id := Low_Bound (N);
5491 H : constant Node_Id := High_Bound (N);
5493 begin
5494 Set_Etype (N, Typ);
5495 Resolve (L, Typ);
5496 Resolve (H, Typ);
5498 Check_Unset_Reference (L);
5499 Check_Unset_Reference (H);
5501 -- We have to check the bounds for being within the base range as
5502 -- required for a non-static context. Normally this is automatic
5503 -- and done as part of evaluating expressions, but the N_Range
5504 -- node is an exception, since in GNAT we consider this node to
5505 -- be a subexpression, even though in Ada it is not. The circuit
5506 -- in Sem_Eval could check for this, but that would put the test
5507 -- on the main evaluation path for expressions.
5509 Check_Non_Static_Context (L);
5510 Check_Non_Static_Context (H);
5512 -- If bounds are static, constant-fold them, so size computations
5513 -- are identical between front-end and back-end. Do not perform this
5514 -- transformation while analyzing generic units, as type information
5515 -- would then be lost when reanalyzing the constant node in the
5516 -- instance.
5518 if Is_Discrete_Type (Typ) and then Expander_Active then
5519 if Is_OK_Static_Expression (L) then
5520 Fold_Uint (L, Expr_Value (L), Is_Static_Expression (L));
5521 end if;
5523 if Is_OK_Static_Expression (H) then
5524 Fold_Uint (H, Expr_Value (H), Is_Static_Expression (H));
5525 end if;
5526 end if;
5527 end Resolve_Range;
5529 --------------------------
5530 -- Resolve_Real_Literal --
5531 --------------------------
5533 procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id) is
5534 Actual_Typ : constant Entity_Id := Etype (N);
5536 begin
5537 -- Special processing for fixed-point literals to make sure that the
5538 -- value is an exact multiple of small where this is required. We
5539 -- skip this for the universal real case, and also for generic types.
5541 if Is_Fixed_Point_Type (Typ)
5542 and then Typ /= Universal_Fixed
5543 and then Typ /= Any_Fixed
5544 and then not Is_Generic_Type (Typ)
5545 then
5546 declare
5547 Val : constant Ureal := Realval (N);
5548 Cintr : constant Ureal := Val / Small_Value (Typ);
5549 Cint : constant Uint := UR_Trunc (Cintr);
5550 Den : constant Uint := Norm_Den (Cintr);
5551 Stat : Boolean;
5553 begin
5554 -- Case of literal is not an exact multiple of the Small
5556 if Den /= 1 then
5558 -- For a source program literal for a decimal fixed-point
5559 -- type, this is statically illegal (RM 4.9(36)).
5561 if Is_Decimal_Fixed_Point_Type (Typ)
5562 and then Actual_Typ = Universal_Real
5563 and then Comes_From_Source (N)
5564 then
5566 end if;
5568 -- Replace literal by a value that is the exact representation
5569 -- of a value of the type, i.e. a multiple of the small value,
5570 -- by truncation, since Machine_Rounds is false for all GNAT
5571 -- fixed-point types (RM 4.9(38)).
5573 Stat := Is_Static_Expression (N);
5574 Rewrite (N,
5575 Make_Real_Literal (Sloc (N),
5576 Realval => Small_Value (Typ) * Cint));
5578 Set_Is_Static_Expression (N, Stat);
5579 end if;
5581 -- In all cases, set the corresponding integer field
5583 Set_Corresponding_Integer_Value (N, Cint);
5584 end;
5585 end if;
5587 -- Now replace the actual type by the expected type as usual
5589 Set_Etype (N, Typ);
5590 Eval_Real_Literal (N);
5591 end Resolve_Real_Literal;
5593 -----------------------
5594 -- Resolve_Reference --
5595 -----------------------
5597 procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id) is
5598 P : constant Node_Id := Prefix (N);
5600 begin
5601 -- Replace general access with specific type
5603 if Ekind (Etype (N)) = E_Allocator_Type then
5604 Set_Etype (N, Base_Type (Typ));
5605 end if;
5607 Resolve (P, Designated_Type (Etype (N)));
5609 -- If we are taking the reference of a volatile entity, then treat
5610 -- it as a potential modification of this entity. This is much too
5611 -- conservative, but is necessary because remove side effects can
5612 -- result in transformations of normal assignments into reference
5613 -- sequences that otherwise fail to notice the modification.
5615 if Is_Entity_Name (P) and then Treat_As_Volatile (Entity (P)) then
5616 Note_Possible_Modification (P);
5617 end if;
5618 end Resolve_Reference;
5620 --------------------------------
5621 -- Resolve_Selected_Component --
5622 --------------------------------
5624 procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id) is
5625 Comp : Entity_Id;
5626 Comp1 : Entity_Id := Empty; -- prevent junk warning
5627 P : constant Node_Id := Prefix (N);
5628 S : constant Node_Id := Selector_Name (N);
5629 T : Entity_Id := Etype (P);
5630 I : Interp_Index;
5631 I1 : Interp_Index := 0; -- prevent junk warning
5632 It : Interp;
5633 It1 : Interp;
5634 Found : Boolean;
5636 function Init_Component return Boolean;
5637 -- Check whether this is the initialization of a component within an
5638 -- init proc (by assignment or call to another init proc). If true,
5639 -- there is no need for a discriminant check.
5641 --------------------
5642 -- Init_Component --
5643 --------------------
5645 function Init_Component return Boolean is
5646 begin
5647 return Inside_Init_Proc
5648 and then Nkind (Prefix (N)) = N_Identifier
5649 and then Chars (Prefix (N)) = Name_uInit
5650 and then Nkind (Parent (Parent (N))) = N_Case_Statement_Alternative;
5651 end Init_Component;
5653 -- Start of processing for Resolve_Selected_Component
5655 begin
5656 if Is_Overloaded (P) then
5658 -- Use the context type to select the prefix that has a selector
5659 -- of the correct name and type.
5661 Found := False;
5662 Get_First_Interp (P, I, It);
5664 Search : while Present (It.Typ) loop
5665 if Is_Access_Type (It.Typ) then
5666 T := Designated_Type (It.Typ);
5667 else
5668 T := It.Typ;
5669 end if;
5671 if Is_Record_Type (T) then
5672 Comp := First_Entity (T);
5674 while Present (Comp) loop
5676 if Chars (Comp) = Chars (S)
5677 and then Covers (Etype (Comp), Typ)
5678 then
5679 if not Found then
5680 Found := True;
5681 I1 := I;
5682 It1 := It;
5683 Comp1 := Comp;
5685 else
5686 It := Disambiguate (P, I1, I, Any_Type);
5688 if It = No_Interp then
5689 Error_Msg_N
5691 Set_Etype (N, Typ);
5692 return;
5694 else
5695 It1 := It;
5697 if Scope (Comp1) /= It1.Typ then
5699 -- Resolution chooses the new interpretation.
5700 -- Find the component with the right name.
5702 Comp1 := First_Entity (It1.Typ);
5704 while Present (Comp1)
5705 and then Chars (Comp1) /= Chars (S)
5706 loop
5707 Comp1 := Next_Entity (Comp1);
5708 end loop;
5709 end if;
5711 exit Search;
5712 end if;
5713 end if;
5714 end if;
5716 Comp := Next_Entity (Comp);
5717 end loop;
5719 end if;
5721 Get_Next_Interp (I, It);
5722 end loop Search;
5724 Resolve (P, It1.Typ);
5725 Set_Etype (N, Typ);
5726 Set_Entity (S, Comp1);
5728 else
5729 -- Resolve prefix with its type
5731 Resolve (P, T);
5732 end if;
5734 -- Deal with access type case
5736 if Is_Access_Type (Etype (P)) then
5737 Apply_Access_Check (N);
5738 T := Designated_Type (Etype (P));
5739 else
5740 T := Etype (P);
5741 end if;
5743 if Has_Discriminants (T)
5744 and then (Ekind (Entity (S)) = E_Component
5745 or else
5746 Ekind (Entity (S)) = E_Discriminant)
5747 and then Present (Original_Record_Component (Entity (S)))
5748 and then Ekind (Original_Record_Component (Entity (S))) = E_Component
5749 and then Present (Discriminant_Checking_Func
5750 (Original_Record_Component (Entity (S))))
5751 and then not Discriminant_Checks_Suppressed (T)
5752 and then not Init_Component
5753 then
5754 Set_Do_Discriminant_Check (N);
5755 end if;
5757 if Ekind (Entity (S)) = E_Void then
5759 end if;
5761 -- If the prefix is a record conversion, this may be a renamed
5762 -- discriminant whose bounds differ from those of the original
5763 -- one, so we must ensure that a range check is performed.
5765 if Nkind (P) = N_Type_Conversion
5766 and then Ekind (Entity (S)) = E_Discriminant
5767 and then Is_Discrete_Type (Typ)
5768 then
5769 Set_Etype (N, Base_Type (Typ));
5770 end if;
5772 -- Note: No Eval processing is required, because the prefix is of a
5773 -- record type, or protected type, and neither can possibly be static.
5775 end Resolve_Selected_Component;
5777 -------------------
5778 -- Resolve_Shift --
5779 -------------------
5781 procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id) is
5782 B_Typ : constant Entity_Id := Base_Type (Typ);
5783 L : constant Node_Id := Left_Opnd (N);
5784 R : constant Node_Id := Right_Opnd (N);
5786 begin
5787 -- We do the resolution using the base type, because intermediate values
5788 -- in expressions always are of the base type, not a subtype of it.
5790 Resolve (L, B_Typ);
5791 Resolve (R, Standard_Natural);
5793 Check_Unset_Reference (L);
5794 Check_Unset_Reference (R);
5796 Set_Etype (N, B_Typ);
5797 Generate_Operator_Reference (N, B_Typ);
5798 Eval_Shift (N);
5799 end Resolve_Shift;
5801 ---------------------------
5802 -- Resolve_Short_Circuit --
5803 ---------------------------
5805 procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id) is
5806 B_Typ : constant Entity_Id := Base_Type (Typ);
5807 L : constant Node_Id := Left_Opnd (N);
5808 R : constant Node_Id := Right_Opnd (N);
5810 begin
5811 Resolve (L, B_Typ);
5812 Resolve (R, B_Typ);
5814 Check_Unset_Reference (L);
5815 Check_Unset_Reference (R);
5817 Set_Etype (N, B_Typ);
5818 Eval_Short_Circuit (N);
5819 end Resolve_Short_Circuit;
5821 -------------------
5822 -- Resolve_Slice --
5823 -------------------
5825 procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id) is
5826 Name : constant Node_Id := Prefix (N);
5827 Drange : constant Node_Id := Discrete_Range (N);
5828 Array_Type : Entity_Id := Empty;
5829 Index : Node_Id;
5831 begin
5832 if Is_Overloaded (Name) then
5834 -- Use the context type to select the prefix that yields the
5835 -- correct array type.
5837 declare
5838 I : Interp_Index;
5839 I1 : Interp_Index := 0;
5840 It : Interp;
5841 P : constant Node_Id := Prefix (N);
5842 Found : Boolean := False;
5844 begin
5845 Get_First_Interp (P, I, It);
5847 while Present (It.Typ) loop
5849 if (Is_Array_Type (It.Typ)
5850 and then Covers (Typ, It.Typ))
5851 or else (Is_Access_Type (It.Typ)
5852 and then Is_Array_Type (Designated_Type (It.Typ))
5853 and then Covers (Typ, Designated_Type (It.Typ)))
5854 then
5855 if Found then
5856 It := Disambiguate (P, I1, I, Any_Type);
5858 if It = No_Interp then
5860 Set_Etype (N, Typ);
5861 return;
5862 else
5863 Found := True;
5864 Array_Type := It.Typ;
5865 I1 := I;
5866 end if;
5867 else
5868 Found := True;
5869 Array_Type := It.Typ;
5870 I1 := I;
5871 end if;
5872 end if;
5874 Get_Next_Interp (I, It);
5875 end loop;
5876 end;
5878 else
5879 Array_Type := Etype (Name);
5880 end if;
5882 Resolve (Name, Array_Type);
5884 if Is_Access_Type (Array_Type) then
5885 Apply_Access_Check (N);
5886 Array_Type := Designated_Type (Array_Type);
5888 elsif Is_Entity_Name (Name)
5889 or else (Nkind (Name) = N_Function_Call
5890 and then not Is_Constrained (Etype (Name)))
5891 then
5892 Array_Type := Get_Actual_Subtype (Name);
5893 end if;
5895 -- If name was overloaded, set slice type correctly now
5897 Set_Etype (N, Array_Type);
5899 -- If the range is specified by a subtype mark, no resolution
5900 -- is necessary.
5902 if not Is_Entity_Name (Drange) then
5903 Index := First_Index (Array_Type);
5904 Resolve (Drange, Base_Type (Etype (Index)));
5906 if Nkind (Drange) = N_Range then
5907 Apply_Range_Check (Drange, Etype (Index));
5908 end if;
5909 end if;
5911 Set_Slice_Subtype (N);
5912 Eval_Slice (N);
5913 end Resolve_Slice;
5915 ----------------------------
5916 -- Resolve_String_Literal --
5917 ----------------------------
5919 procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id) is
5920 C_Typ : constant Entity_Id := Component_Type (Typ);
5921 R_Typ : constant Entity_Id := Root_Type (C_Typ);
5922 Loc : constant Source_Ptr := Sloc (N);
5923 Str : constant String_Id := Strval (N);
5924 Strlen : constant Nat := String_Length (Str);
5925 Subtype_Id : Entity_Id;
5926 Need_Check : Boolean;
5928 begin
5929 -- For a string appearing in a concatenation, defer creation of the
5930 -- string_literal_subtype until the end of the resolution of the
5931 -- concatenation, because the literal may be constant-folded away.
5932 -- This is a useful optimization for long concatenation expressions.
5934 -- If the string is an aggregate built for a single character (which
5935 -- happens in a non-static context) or a is null string to which special
5936 -- checks may apply, we build the subtype. Wide strings must also get
5937 -- a string subtype if they come from a one character aggregate. Strings
5938 -- generated by attributes might be static, but it is often hard to
5939 -- determine whether the enclosing context is static, so we generate
5940 -- subtypes for them as well, thus losing some rarer optimizations ???
5941 -- Same for strings that come from a static conversion.
5943 Need_Check :=
5944 (Strlen = 0 and then Typ /= Standard_String)
5945 or else Nkind (Parent (N)) /= N_Op_Concat
5946 or else (N /= Left_Opnd (Parent (N))
5947 and then N /= Right_Opnd (Parent (N)))
5948 or else (Typ = Standard_Wide_String
5949 and then Nkind (Original_Node (N)) /= N_String_Literal);
5951 -- If the resolving type is itself a string literal subtype, we
5952 -- can just reuse it, since there is no point in creating another.
5954 if Ekind (Typ) = E_String_Literal_Subtype then
5955 Subtype_Id := Typ;
5957 elsif Nkind (Parent (N)) = N_Op_Concat
5958 and then not Need_Check
5959 and then Nkind (Original_Node (N)) /= N_Character_Literal
5960 and then Nkind (Original_Node (N)) /= N_Attribute_Reference
5961 and then Nkind (Original_Node (N)) /= N_Qualified_Expression
5962 and then Nkind (Original_Node (N)) /= N_Type_Conversion
5963 then
5964 Subtype_Id := Typ;
5966 -- Otherwise we must create a string literal subtype. Note that the
5967 -- whole idea of string literal subtypes is simply to avoid the need
5968 -- for building a full fledged array subtype for each literal.
5969 else
5970 Set_String_Literal_Subtype (N, Typ);
5971 Subtype_Id := Etype (N);
5972 end if;
5974 if Nkind (Parent (N)) /= N_Op_Concat
5975 or else Need_Check
5976 then
5977 Set_Etype (N, Subtype_Id);
5978 Eval_String_Literal (N);
5979 end if;
5981 if Is_Limited_Composite (Typ)
5982 or else Is_Private_Composite (Typ)
5983 then
5985 Set_Etype (N, Any_Type);
5986 return;
5987 end if;
5989 -- The validity of a null string has been checked in the
5990 -- call to Eval_String_Literal.
5992 if Strlen = 0 then
5993 return;
5995 -- Always accept string literal with component type Any_Character,
5996 -- which occurs in error situations and in comparisons of literals,
5997 -- both of which should accept all literals.
5999 elsif R_Typ = Any_Character then
6000 return;
6002 -- If the type is bit-packed, then we always tranform the string
6003 -- literal into a full fledged aggregate.
6005 elsif Is_Bit_Packed_Array (Typ) then
6006 null;
6008 -- Deal with cases of Wide_String and String
6010 else
6011 -- For Standard.Wide_String, or any other type whose component
6012 -- type is Standard.Wide_Character, we know that all the
6013 -- characters in the string must be acceptable, since the parser
6014 -- accepted the characters as valid character literals.
6016 if R_Typ = Standard_Wide_Character then
6017 null;
6019 -- For the case of Standard.String, or any other type whose
6020 -- component type is Standard.Character, we must make sure that
6021 -- there are no wide characters in the string, i.e. that it is
6022 -- entirely composed of characters in range of type String.
6024 -- If the string literal is the result of a static concatenation,
6025 -- the test has already been performed on the components, and need
6026 -- not be repeated.
6028 elsif R_Typ = Standard_Character
6029 and then Nkind (Original_Node (N)) /= N_Op_Concat
6030 then
6031 for J in 1 .. Strlen loop
6032 if not In_Character_Range (Get_String_Char (Str, J)) then
6034 -- If we are out of range, post error. This is one of the
6035 -- very few places that we place the flag in the middle of
6036 -- a token, right under the offending wide character.
6038 Error_Msg
6040 Source_Ptr (Int (Loc) + J));
6041 return;
6042 end if;
6043 end loop;
6045 -- If the root type is not a standard character, then we will convert
6046 -- the string into an aggregate and will let the aggregate code do
6047 -- the checking.
6049 else
6050 null;
6052 end if;
6054 -- See if the component type of the array corresponding to the
6055 -- string has compile time known bounds. If yes we can directly
6056 -- check whether the evaluation of the string will raise constraint
6057 -- error. Otherwise we need to transform the string literal into
6058 -- the corresponding character aggregate and let the aggregate
6059 -- code do the checking.
6061 if R_Typ = Standard_Wide_Character
6062 or else R_Typ = Standard_Character
6063 then
6064 -- Check for the case of full range, where we are definitely OK
6066 if Component_Type (Typ) = Base_Type (Component_Type (Typ)) then
6067 return;
6068 end if;
6070 -- Here the range is not the complete base type range, so check
6072 declare
6073 Comp_Typ_Lo : constant Node_Id :=
6074 Type_Low_Bound (Component_Type (Typ));
6075 Comp_Typ_Hi : constant Node_Id :=
6076 Type_High_Bound (Component_Type (Typ));
6078 Char_Val : Uint;
6080 begin
6081 if Compile_Time_Known_Value (Comp_Typ_Lo)
6082 and then Compile_Time_Known_Value (Comp_Typ_Hi)
6083 then
6084 for J in 1 .. Strlen loop
6085 Char_Val := UI_From_Int (Int (Get_String_Char (Str, J)));
6087 if Char_Val < Expr_Value (Comp_Typ_Lo)
6088 or else Char_Val > Expr_Value (Comp_Typ_Hi)
6089 then
6090 Apply_Compile_Time_Constraint_Error
6092 Loc => Source_Ptr (Int (Loc) + J));
6093 end if;
6094 end loop;
6096 return;
6097 end if;
6098 end;
6099 end if;
6100 end if;
6102 -- If we got here we meed to transform the string literal into the
6103 -- equivalent qualified positional array aggregate. This is rather
6104 -- heavy artillery for this situation, but it is hard work to avoid.
6106 declare
6107 Lits : constant List_Id := New_List;
6108 P : Source_Ptr := Loc + 1;
6109 C : Char_Code;
6111 begin
6112 -- Build the character literals, we give them source locations
6113 -- that correspond to the string positions, which is a bit tricky
6114 -- given the possible presence of wide character escape sequences.
6116 for J in 1 .. Strlen loop
6117 C := Get_String_Char (Str, J);
6118 Set_Character_Literal_Name (C);
6120 Append_To (Lits,
6121 Make_Character_Literal (P, Name_Find, C));
6123 if In_Character_Range (C) then
6124 P := P + 1;
6126 -- Should we have a call to Skip_Wide here ???
6127 -- ??? else
6128 -- Skip_Wide (P);
6130 end if;
6131 end loop;
6133 Rewrite (N,
6134 Make_Qualified_Expression (Loc,
6135 Subtype_Mark => New_Reference_To (Typ, Loc),
6136 Expression =>
6137 Make_Aggregate (Loc, Expressions => Lits)));
6139 Analyze_And_Resolve (N, Typ);
6140 end;
6141 end Resolve_String_Literal;
6143 -----------------------------
6144 -- Resolve_Subprogram_Info --
6145 -----------------------------
6147 procedure Resolve_Subprogram_Info (N : Node_Id; Typ : Entity_Id) is
6148 begin
6149 Set_Etype (N, Typ);
6150 end Resolve_Subprogram_Info;
6152 -----------------------------
6153 -- Resolve_Type_Conversion --
6154 -----------------------------
6156 procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id) is
6157 Target_Type : constant Entity_Id := Etype (N);
6158 Conv_OK : constant Boolean := Conversion_OK (N);
6159 Operand : Node_Id;
6160 Opnd_Type : Entity_Id;
6161 Rop : Node_Id;
6162 Orig_N : Node_Id;
6163 Orig_T : Node_Id;
6165 begin
6166 Operand := Expression (N);
6168 if not Conv_OK
6169 and then not Valid_Conversion (N, Target_Type, Operand)
6170 then
6171 return;
6172 end if;
6174 if Etype (Operand) = Any_Fixed then
6176 -- Mixed-mode operation involving a literal. Context must be a fixed
6177 -- type which is applied to the literal subsequently.
6179 if Is_Fixed_Point_Type (Typ) then
6180 Set_Etype (Operand, Universal_Real);
6182 elsif Is_Numeric_Type (Typ)
6183 and then (Nkind (Operand) = N_Op_Multiply
6184 or else Nkind (Operand) = N_Op_Divide)
6185 and then (Etype (Right_Opnd (Operand)) = Universal_Real
6186 or else Etype (Left_Opnd (Operand)) = Universal_Real)
6187 then
6188 if Unique_Fixed_Point_Type (N) = Any_Type then
6189 return; -- expression is ambiguous.
6190 else
6191 Set_Etype (Operand, Standard_Duration);
6192 end if;
6194 if Etype (Right_Opnd (Operand)) = Universal_Real then
6195 Rop := New_Copy_Tree (Right_Opnd (Operand));
6196 else
6197 Rop := New_Copy_Tree (Left_Opnd (Operand));
6198 end if;
6200 Resolve (Rop, Standard_Long_Long_Float);
6202 if Realval (Rop) /= Ureal_0
6203 and then abs (Realval (Rop)) < Delta_Value (Standard_Duration)
6204 then
6206 Rop);
6208 end if;
6210 elsif Is_Numeric_Type (Typ)
6211 and then Nkind (Operand) in N_Op
6212 and then Unique_Fixed_Point_Type (N) /= Any_Type
6213 then
6214 Set_Etype (Operand, Standard_Duration);
6216 else
6218 Set_Etype (Operand, Any_Type);
6219 return;
6220 end if;
6221 end if;
6223 Opnd_Type := Etype (Operand);
6224 Resolve (Operand);
6226 -- Note: we do the Eval_Type_Conversion call before applying the
6227 -- required checks for a subtype conversion. This is important,
6228 -- since both are prepared under certain circumstances to change
6229 -- the type conversion to a constraint error node, but in the case
6230 -- of Eval_Type_Conversion this may reflect an illegality in the
6231 -- static case, and we would miss the illegality (getting only a
6232 -- warning message), if we applied the type conversion checks first.
6234 Eval_Type_Conversion (N);
6236 -- If after evaluation, we still have a type conversion, then we
6237 -- may need to apply checks required for a subtype conversion.
6239 -- Skip these type conversion checks if universal fixed operands
6240 -- operands involved, since range checks are handled separately for
6241 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
6243 if Nkind (N) = N_Type_Conversion
6244 and then not Is_Generic_Type (Root_Type (Target_Type))
6245 and then Target_Type /= Universal_Fixed
6246 and then Opnd_Type /= Universal_Fixed
6247 then
6248 Apply_Type_Conversion_Checks (N);
6249 end if;
6251 -- Issue warning for conversion of simple object to its own type
6252 -- We have to test the original nodes, since they may have been
6253 -- rewritten by various optimizations.
6255 Orig_N := Original_Node (N);
6257 if Warn_On_Redundant_Constructs
6258 and then Comes_From_Source (Orig_N)
6259 and then Nkind (Orig_N) = N_Type_Conversion
6260 then
6261 Orig_N := Original_Node (Expression (Orig_N));
6262 Orig_T := Target_Type;
6264 -- If the node is part of a larger expression, the Target_Type
6265 -- may not be the original type of the node if the context is a
6266 -- condition. Recover original type to see if conversion is needed.
6268 if Is_Boolean_Type (Orig_T)
6269 and then Nkind (Parent (N)) in N_Op
6270 then
6271 Orig_T := Etype (Parent (N));
6272 end if;
6274 if Is_Entity_Name (Orig_N)
6275 and then Etype (Entity (Orig_N)) = Orig_T
6276 then
6277 Error_Msg_NE
6279 end if;
6280 end if;
6281 end Resolve_Type_Conversion;
6283 ----------------------
6284 -- Resolve_Unary_Op --
6285 ----------------------
6287 procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id) is
6288 B_Typ : constant Entity_Id := Base_Type (Typ);
6289 R : constant Node_Id := Right_Opnd (N);
6290 OK : Boolean;
6291 Lo : Uint;
6292 Hi : Uint;
6294 begin
6295 -- Generate warning for expressions like abs (x mod 2)
6297 if Warn_On_Redundant_Constructs
6298 and then Nkind (N) = N_Op_Abs
6299 then
6300 Determine_Range (Right_Opnd (N), OK, Lo, Hi);
6302 if OK and then Hi >= Lo and then Lo >= 0 then
6303 Error_Msg_N
6305 end if;
6306 end if;
6308 -- Generate warning for expressions like -5 mod 3
6310 if Paren_Count (N) = 0
6311 and then Nkind (N) = N_Op_Minus
6312 and then Nkind (Right_Opnd (N)) = N_Op_Mod
6313 and then Comes_From_Source (N)
6314 then
6315 Error_Msg_N
6317 end if;
6319 if Comes_From_Source (N)
6320 and then Ekind (Entity (N)) = E_Function
6321 and then Is_Imported (Entity (N))
6322 and then Is_Intrinsic_Subprogram (Entity (N))
6323 then
6324 Resolve_Intrinsic_Unary_Operator (N, Typ);
6325 return;
6326 end if;
6328 if Etype (R) = Universal_Integer
6329 or else Etype (R) = Universal_Real
6330 then
6331 Check_For_Visible_Operator (N, B_Typ);
6332 end if;
6334 Set_Etype (N, B_Typ);
6335 Resolve (R, B_Typ);
6337 Check_Unset_Reference (R);
6338 Generate_Operator_Reference (N, B_Typ);
6339 Eval_Unary_Op (N);
6341 -- Set overflow checking bit. Much cleverer code needed here eventually
6342 -- and perhaps the Resolve routines should be separated for the various
6343 -- arithmetic operations, since they will need different processing ???
6345 if Nkind (N) in N_Op then
6346 if not Overflow_Checks_Suppressed (Etype (N)) then
6347 Enable_Overflow_Check (N);
6348 end if;
6349 end if;
6350 end Resolve_Unary_Op;
6352 ----------------------------------
6353 -- Resolve_Unchecked_Expression --
6354 ----------------------------------
6356 procedure Resolve_Unchecked_Expression
6357 (N : Node_Id;
6358 Typ : Entity_Id)
6359 is
6360 begin
6361 Resolve (Expression (N), Typ, Suppress => All_Checks);
6362 Set_Etype (N, Typ);
6363 end Resolve_Unchecked_Expression;
6365 ---------------------------------------
6366 -- Resolve_Unchecked_Type_Conversion --
6367 ---------------------------------------
6369 procedure Resolve_Unchecked_Type_Conversion
6370 (N : Node_Id;
6371 Typ : Entity_Id)
6372 is
6373 pragma Warnings (Off, Typ);
6375 Operand : constant Node_Id := Expression (N);
6376 Opnd_Type : constant Entity_Id := Etype (Operand);
6378 begin
6379 -- Resolve operand using its own type.
6381 Resolve (Operand, Opnd_Type);
6382 Eval_Unchecked_Conversion (N);
6384 end Resolve_Unchecked_Type_Conversion;
6386 ------------------------------
6387 -- Rewrite_Operator_As_Call --
6388 ------------------------------
6390 procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id) is
6391 Loc : constant Source_Ptr := Sloc (N);
6392 Actuals : constant List_Id := New_List;
6393 New_N : Node_Id;
6395 begin
6396 if Nkind (N) in N_Binary_Op then
6397 Append (Left_Opnd (N), Actuals);
6398 end if;
6400 Append (Right_Opnd (N), Actuals);
6402 New_N :=
6403 Make_Function_Call (Sloc => Loc,
6404 Name => New_Occurrence_Of (Nam, Loc),
6405 Parameter_Associations => Actuals);
6407 Preserve_Comes_From_Source (New_N, N);
6408 Preserve_Comes_From_Source (Name (New_N), N);
6409 Rewrite (N, New_N);
6410 Set_Etype (N, Etype (Nam));
6411 end Rewrite_Operator_As_Call;
6413 ------------------------------
6414 -- Rewrite_Renamed_Operator --
6415 ------------------------------
6417 procedure Rewrite_Renamed_Operator (N : Node_Id; Op : Entity_Id) is
6418 Nam : constant Name_Id := Chars (Op);
6419 Is_Binary : constant Boolean := Nkind (N) in N_Binary_Op;
6420 Op_Node : Node_Id;
6422 begin
6423 -- Rewrite the operator node using the real operator, not its
6424 -- renaming. Exclude user-defined intrinsic operations, which
6425 -- are treated separately.
6427 if Ekind (Op) /= E_Function then
6428 Op_Node := New_Node (Operator_Kind (Nam, Is_Binary), Sloc (N));
6429 Set_Chars (Op_Node, Nam);
6430 Set_Etype (Op_Node, Etype (N));
6431 Set_Entity (Op_Node, Op);
6432 Set_Right_Opnd (Op_Node, Right_Opnd (N));
6434 -- Indicate that both the original entity and its renaming
6435 -- are referenced at this point.
6437 Generate_Reference (Entity (N), N);
6438 Generate_Reference (Op, N);
6440 if Is_Binary then
6441 Set_Left_Opnd (Op_Node, Left_Opnd (N));
6442 end if;
6444 Rewrite (N, Op_Node);
6445 end if;
6446 end Rewrite_Renamed_Operator;
6448 -----------------------
6449 -- Set_Slice_Subtype --
6450 -----------------------
6452 -- Build an implicit subtype declaration to represent the type delivered
6453 -- by the slice. This is an abbreviated version of an array subtype. We
6454 -- define an index subtype for the slice, using either the subtype name
6455 -- or the discrete range of the slice. To be consistent with index usage
6456 -- elsewhere, we create a list header to hold the single index. This list
6457 -- is not otherwise attached to the syntax tree.
6459 procedure Set_Slice_Subtype (N : Node_Id) is
6460 Loc : constant Source_Ptr := Sloc (N);
6461 Index_List : constant List_Id := New_List;
6462 Index : Node_Id;
6463 Index_Subtype : Entity_Id;
6464 Index_Type : Entity_Id;
6465 Slice_Subtype : Entity_Id;
6466 Drange : constant Node_Id := Discrete_Range (N);
6468 begin
6469 if Is_Entity_Name (Drange) then
6470 Index_Subtype := Entity (Drange);
6472 else
6473 -- We force the evaluation of a range. This is definitely needed in
6474 -- the renamed case, and seems safer to do unconditionally. Note in
6475 -- any case that since we will create and insert an Itype referring
6476 -- to this range, we must make sure any side effect removal actions
6477 -- are inserted before the Itype definition.
6479 if Nkind (Drange) = N_Range then
6480 Force_Evaluation (Low_Bound (Drange));
6481 Force_Evaluation (High_Bound (Drange));
6482 end if;
6484 Index_Type := Base_Type (Etype (Drange));
6486 Index_Subtype := Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
6488 Set_Scalar_Range (Index_Subtype, Drange);
6489 Set_Etype (Index_Subtype, Index_Type);
6490 Set_Size_Info (Index_Subtype, Index_Type);
6491 Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
6492 end if;
6494 Slice_Subtype := Create_Itype (E_Array_Subtype, N);
6496 Index := New_Occurrence_Of (Index_Subtype, Loc);
6497 Set_Etype (Index, Index_Subtype);
6498 Append (Index, Index_List);
6500 Set_First_Index (Slice_Subtype, Index);
6501 Set_Etype (Slice_Subtype, Base_Type (Etype (N)));
6502 Set_Is_Constrained (Slice_Subtype, True);
6503 Init_Size_Align (Slice_Subtype);
6505 Check_Compile_Time_Size (Slice_Subtype);
6507 -- The Etype of the existing Slice node is reset to this slice
6508 -- subtype. Its bounds are obtained from its first index.
6510 Set_Etype (N, Slice_Subtype);
6512 -- In the packed case, this must be immediately frozen
6514 -- Couldn't we always freeze here??? and if we did, then the above
6515 -- call to Check_Compile_Time_Size could be eliminated, which would
6516 -- be nice, because then that routine could be made private to Freeze.
6518 if Is_Packed (Slice_Subtype) and not In_Default_Expression then
6519 Freeze_Itype (Slice_Subtype, N);
6520 end if;
6522 end Set_Slice_Subtype;
6524 --------------------------------
6525 -- Set_String_Literal_Subtype --
6526 --------------------------------
6528 procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id) is
6529 Subtype_Id : Entity_Id;
6531 begin
6532 if Nkind (N) /= N_String_Literal then
6533 return;
6534 else
6535 Subtype_Id := Create_Itype (E_String_Literal_Subtype, N);
6536 end if;
6538 Set_String_Literal_Length (Subtype_Id,
6539 UI_From_Int (String_Length (Strval (N))));
6540 Set_Etype (Subtype_Id, Base_Type (Typ));
6541 Set_Is_Constrained (Subtype_Id);
6543 -- The low bound is set from the low bound of the corresponding
6544 -- index type. Note that we do not store the high bound in the
6545 -- string literal subtype, but it can be deduced if necssary
6546 -- from the length and the low bound.
6548 Set_String_Literal_Low_Bound
6549 (Subtype_Id, Type_Low_Bound (Etype (First_Index (Typ))));
6551 Set_Etype (N, Subtype_Id);
6552 end Set_String_Literal_Subtype;
6554 -----------------------------
6555 -- Unique_Fixed_Point_Type --
6556 -----------------------------
6558 function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id is
6559 T1 : Entity_Id := Empty;
6560 T2 : Entity_Id;
6561 Item : Node_Id;
6562 Scop : Entity_Id;
6564 procedure Fixed_Point_Error;
6565 -- If true ambiguity, give details.
6567 procedure Fixed_Point_Error is
6568 begin
6572 end Fixed_Point_Error;
6574 begin
6575 -- The operations on Duration are visible, so Duration is always a
6576 -- possible interpretation.
6578 T1 := Standard_Duration;
6580 -- Look for fixed-point types in enclosing scopes.
6582 Scop := Current_Scope;
6583 while Scop /= Standard_Standard loop
6584 T2 := First_Entity (Scop);
6586 while Present (T2) loop
6587 if Is_Fixed_Point_Type (T2)
6588 and then Current_Entity (T2) = T2
6589 and then Scope (Base_Type (T2)) = Scop
6590 then
6591 if Present (T1) then
6592 Fixed_Point_Error;
6593 return Any_Type;
6594 else
6595 T1 := T2;
6596 end if;
6597 end if;
6599 Next_Entity (T2);
6600 end loop;
6602 Scop := Scope (Scop);
6603 end loop;
6605 -- Look for visible fixed type declarations in the context.
6607 Item := First (Context_Items (Cunit (Current_Sem_Unit)));
6609 while Present (Item) loop
6610 if Nkind (Item) = N_With_Clause then
6611 Scop := Entity (Name (Item));
6612 T2 := First_Entity (Scop);
6614 while Present (T2) loop
6615 if Is_Fixed_Point_Type (T2)
6616 and then Scope (Base_Type (T2)) = Scop
6617 and then (Is_Potentially_Use_Visible (T2)
6618 or else In_Use (T2))
6619 then
6620 if Present (T1) then
6621 Fixed_Point_Error;
6622 return Any_Type;
6623 else
6624 T1 := T2;
6625 end if;
6626 end if;
6628 Next_Entity (T2);
6629 end loop;
6630 end if;
6632 Next (Item);
6633 end loop;
6635 if Nkind (N) = N_Real_Literal then
6638 else
6640 end if;
6642 return T1;
6643 end Unique_Fixed_Point_Type;
6645 ----------------------
6646 -- Valid_Conversion --
6647 ----------------------
6649 function Valid_Conversion
6650 (N : Node_Id;
6651 Target : Entity_Id;
6652 Operand : Node_Id)
6653 return Boolean
6654 is
6655 Target_Type : constant Entity_Id := Base_Type (Target);
6656 Opnd_Type : Entity_Id := Etype (Operand);
6658 function Conversion_Check
6659 (Valid : Boolean;
6660 Msg : String)
6661 return Boolean;
6662 -- Little routine to post Msg if Valid is False, returns Valid value
6664 function Valid_Tagged_Conversion
6665 (Target_Type : Entity_Id;
6666 Opnd_Type : Entity_Id)
6667 return Boolean;
6668 -- Specifically test for validity of tagged conversions
6670 ----------------------
6671 -- Conversion_Check --
6672 ----------------------
6674 function Conversion_Check
6675 (Valid : Boolean;
6676 Msg : String)
6677 return Boolean
6678 is
6679 begin
6680 if not Valid then
6681 Error_Msg_N (Msg, Operand);
6682 end if;
6684 return Valid;
6685 end Conversion_Check;
6687 -----------------------------
6688 -- Valid_Tagged_Conversion --
6689 -----------------------------
6691 function Valid_Tagged_Conversion
6692 (Target_Type : Entity_Id;
6693 Opnd_Type : Entity_Id)
6694 return Boolean
6695 is
6696 begin
6697 -- Upward conversions are allowed (RM 4.6(22)).
6699 if Covers (Target_Type, Opnd_Type)
6700 or else Is_Ancestor (Target_Type, Opnd_Type)
6701 then
6702 return True;
6704 -- Downward conversion are allowed if the operand is
6705 -- is class-wide (RM 4.6(23)).
6707 elsif Is_Class_Wide_Type (Opnd_Type)
6708 and then Covers (Opnd_Type, Target_Type)
6709 then
6710 return True;
6712 elsif Covers (Opnd_Type, Target_Type)
6713 or else Is_Ancestor (Opnd_Type, Target_Type)
6714 then
6715 return
6716 Conversion_Check (False,
6718 else
6719 Error_Msg_NE
6721 N, First_Subtype (Opnd_Type));
6722 return False;
6723 end if;
6724 end Valid_Tagged_Conversion;
6726 -- Start of processing for Valid_Conversion
6728 begin
6729 Check_Parameterless_Call (Operand);
6731 if Is_Overloaded (Operand) then
6732 declare
6733 I : Interp_Index;
6734 I1 : Interp_Index;
6735 It : Interp;
6736 It1 : Interp;
6737 N1 : Entity_Id;
6739 begin
6740 -- Remove procedure calls, which syntactically cannot appear
6741 -- in this context, but which cannot be removed by type checking,
6742 -- because the context does not impose a type.
6744 Get_First_Interp (Operand, I, It);
6746 while Present (It.Typ) loop
6748 if It.Typ = Standard_Void_Type then
6749 Remove_Interp (I);
6750 end if;
6752 Get_Next_Interp (I, It);
6753 end loop;
6755 Get_First_Interp (Operand, I, It);
6756 I1 := I;
6757 It1 := It;
6759 if No (It.Typ) then
6761 return False;
6762 end if;
6764 Get_Next_Interp (I, It);
6766 if Present (It.Typ) then
6767 N1 := It1.Nam;
6768 It1 := Disambiguate (Operand, I1, I, Any_Type);
6770 if It1 = No_Interp then
6773 Error_Msg_Sloc := Sloc (It.Nam);
6776 Error_Msg_Sloc := Sloc (N1);
6779 return False;
6780 end if;
6781 end if;
6783 Set_Etype (Operand, It1.Typ);
6784 Opnd_Type := It1.Typ;
6785 end;
6786 end if;
6788 if Chars (Current_Scope) = Name_Unchecked_Conversion then
6790 -- This check is dubious, what if there were a user defined
6791 -- scope whose name was Unchecked_Conversion ???
6793 return True;
6795 elsif Is_Numeric_Type (Target_Type) then
6796 if Opnd_Type = Universal_Fixed then
6797 return True;
6798 else
6799 return Conversion_Check (Is_Numeric_Type (Opnd_Type),
6801 end if;
6803 elsif Is_Array_Type (Target_Type) then
6804 if not Is_Array_Type (Opnd_Type)
6805 or else Opnd_Type = Any_Composite
6806 or else Opnd_Type = Any_String
6807 then
6808 Error_Msg_N
6810 return False;
6812 elsif Number_Dimensions (Target_Type) /=
6813 Number_Dimensions (Opnd_Type)
6814 then
6815 Error_Msg_N
6817 return False;
6819 else
6820 declare
6821 Target_Index : Node_Id := First_Index (Target_Type);
6822 Opnd_Index : Node_Id := First_Index (Opnd_Type);
6824 Target_Index_Type : Entity_Id;
6825 Opnd_Index_Type : Entity_Id;
6827 Target_Comp_Type : constant Entity_Id :=
6828 Component_Type (Target_Type);
6829 Opnd_Comp_Type : constant Entity_Id :=
6830 Component_Type (Opnd_Type);
6832 begin
6833 while Present (Target_Index) and then Present (Opnd_Index) loop
6834 Target_Index_Type := Etype (Target_Index);
6835 Opnd_Index_Type := Etype (Opnd_Index);
6837 if not (Is_Integer_Type (Target_Index_Type)
6838 and then Is_Integer_Type (Opnd_Index_Type))
6839 and then (Root_Type (Target_Index_Type)
6840 /= Root_Type (Opnd_Index_Type))
6841 then
6842 Error_Msg_N
6844 Operand);
6845 return False;
6846 end if;
6848 Next_Index (Target_Index);
6849 Next_Index (Opnd_Index);
6850 end loop;
6852 if Base_Type (Target_Comp_Type) /=
6853 Base_Type (Opnd_Comp_Type)
6854 then
6855 Error_Msg_N
6857 Operand);
6858 return False;
6860 elsif
6861 Is_Constrained (Target_Comp_Type)
6862 /= Is_Constrained (Opnd_Comp_Type)
6863 or else not Subtypes_Statically_Match
6864 (Target_Comp_Type, Opnd_Comp_Type)
6865 then
6866 Error_Msg_N
6868 return False;
6870 end if;
6871 end;
6872 end if;
6874 return True;
6876 elsif (Ekind (Target_Type) = E_General_Access_Type
6877 or else Ekind (Target_Type) = E_Anonymous_Access_Type)
6878 and then
6879 Conversion_Check
6880 (Is_Access_Type (Opnd_Type)
6881 and then Ekind (Opnd_Type) /=
6882 E_Access_Subprogram_Type
6883 and then Ekind (Opnd_Type) /=
6884 E_Access_Protected_Subprogram_Type,
6886 then
6887 if Is_Access_Constant (Opnd_Type)
6888 and then not Is_Access_Constant (Target_Type)
6889 then
6890 Error_Msg_N
6892 return False;
6893 end if;
6895 -- Check the static accessibility rule of 4.6(17). Note that
6896 -- the check is not enforced when within an instance body, since
6897 -- the RM requires such cases to be caught at run time.
6899 if Ekind (Target_Type) /= E_Anonymous_Access_Type then
6900 if Type_Access_Level (Opnd_Type)
6901 > Type_Access_Level (Target_Type)
6902 then
6903 -- In an instance, this is a run-time check, but one we
6904 -- know will fail, so generate an appropriate warning.
6905 -- The raise will be generated by Expand_N_Type_Conversion.
6907 if In_Instance_Body then
6908 Error_Msg_N
6910 Operand);
6911 Error_Msg_N
6914 else
6915 Error_Msg_N
6917 Operand);
6918 return False;
6919 end if;
6921 elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type then
6923 -- When the operand is a selected access discriminant
6924 -- the check needs to be made against the level of the
6925 -- object denoted by the prefix of the selected name.
6926 -- (Object_Access_Level handles checking the prefix
6927 -- of the operand for this case.)
6929 if Nkind (Operand) = N_Selected_Component
6930 and then Object_Access_Level (Operand)
6931 > Type_Access_Level (Target_Type)
6932 then
6933 -- In an instance, this is a run-time check, but one we
6934 -- know will fail, so generate an appropriate warning.
6935 -- The raise will be generated by Expand_N_Type_Conversion.
6937 if In_Instance_Body then
6938 Error_Msg_N
6941 Error_Msg_N
6944 else
6945 Error_Msg_N
6948 return False;
6949 end if;
6950 end if;
6952 -- The case of a reference to an access discriminant
6953 -- from within a type declaration (which will appear
6954 -- as a discriminal) is always illegal because the
6955 -- level of the discriminant is considered to be
6956 -- deeper than any (namable) access type.
6958 if Is_Entity_Name (Operand)
6959 and then (Ekind (Entity (Operand)) = E_In_Parameter
6960 or else Ekind (Entity (Operand)) = E_Constant)
6961 and then Present (Discriminal_Link (Entity (Operand)))
6962 then
6963 Error_Msg_N
6965 Operand);
6966 return False;
6967 end if;
6968 end if;
6969 end if;
6971 declare
6972 Target : constant Entity_Id := Designated_Type (Target_Type);
6973 Opnd : constant Entity_Id := Designated_Type (Opnd_Type);
6975 begin
6976 if Is_Tagged_Type (Target) then
6977 return Valid_Tagged_Conversion (Target, Opnd);
6979 else
6980 if Base_Type (Target) /= Base_Type (Opnd) then
6981 Error_Msg_NE
6983 N, Base_Type (Opnd));
6984 return False;
6986 elsif not Subtypes_Statically_Match (Target, Opnd)
6987 and then (not Has_Discriminants (Target)
6988 or else Is_Constrained (Target))
6989 then
6990 Error_Msg_NE
6992 N, Opnd);
6993 return False;
6995 else
6996 return True;
6997 end if;
6998 end if;
6999 end;
7001 elsif Ekind (Target_Type) = E_Access_Subprogram_Type
7002 and then Conversion_Check
7003 (Ekind (Base_Type (Opnd_Type)) = E_Access_Subprogram_Type,
7005 then
7006 -- Check that the designated types are subtype conformant
7008 if not Subtype_Conformant (Designated_Type (Opnd_Type),
7009 Designated_Type (Target_Type))
7010 then
7011 Error_Msg_N
7013 Operand);
7014 end if;
7016 -- Check the static accessibility rule of 4.6(20)
7018 if Type_Access_Level (Opnd_Type) >
7019 Type_Access_Level (Target_Type)
7020 then
7021 Error_Msg_N
7023 Operand);
7025 -- Check that if the operand type is declared in a generic body,
7026 -- then the target type must be declared within that same body
7027 -- (enforces last sentence of 4.6(20)).
7029 elsif Present (Enclosing_Generic_Body (Opnd_Type)) then
7030 declare
7031 O_Gen : constant Node_Id :=
7032 Enclosing_Generic_Body (Opnd_Type);
7034 T_Gen : Node_Id :=
7035 Enclosing_Generic_Body (Target_Type);
7037 begin
7038 while Present (T_Gen) and then T_Gen /= O_Gen loop
7039 T_Gen := Enclosing_Generic_Body (T_Gen);
7040 end loop;
7042 if T_Gen /= O_Gen then
7043 Error_Msg_N
7046 end if;
7047 end;
7048 end if;
7050 return True;
7052 elsif Is_Remote_Access_To_Subprogram_Type (Target_Type)
7053 and then Is_Remote_Access_To_Subprogram_Type (Opnd_Type)
7054 then
7055 -- It is valid to convert from one RAS type to another provided
7056 -- that their specification statically match.
7058 Check_Subtype_Conformant
7059 (New_Id =>
7060 Designated_Type (Corresponding_Remote_Type (Target_Type)),
7061 Old_Id =>
7062 Designated_Type (Corresponding_Remote_Type (Opnd_Type)),
7063 Err_Loc =>
7064 N);
7065 return True;
7067 elsif Is_Tagged_Type (Target_Type) then
7068 return Valid_Tagged_Conversion (Target_Type, Opnd_Type);
7070 -- Types derived from the same root type are convertible.
7072 elsif Root_Type (Target_Type) = Root_Type (Opnd_Type) then
7073 return True;
7075 -- In an instance, there may be inconsistent views of the same
7076 -- type, or types derived from the same type.
7078 elsif In_Instance
7079 and then Underlying_Type (Target_Type) = Underlying_Type (Opnd_Type)
7080 then
7081 return True;
7083 -- Special check for common access type error case
7085 elsif Ekind (Target_Type) = E_Access_Type
7086 and then Is_Access_Type (Opnd_Type)
7087 then
7091 return False;
7093 else
7095 N, Opnd_Type);
7097 return False;
7098 end if;
7099 end Valid_Conversion;
7101 end Sem_Res;