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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) 1992-2004, 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 ------------------------------------------------------------------------------
75 -----------------------
76 -- Local Subprograms --
77 -----------------------
79 -- Second pass (top-down) type checking and overload resolution procedures
80 -- Typ is the type required by context. These procedures propagate the
81 -- type information recursively to the descendants of N. If the node
82 -- is not overloaded, its Etype is established in the first pass. If
83 -- overloaded, the Resolve routines set the correct type. For arith.
84 -- operators, the Etype is the base type of the context.
86 -- Note that Resolve_Attribute is separated off in Sem_Attr
89 -- Give list of candidate interpretations when a character literal cannot
90 -- be resolved.
93 -- N is a binary operator node which may possibly operate on Boolean
94 -- operands. If the operator does have Boolean operands, then a call is
95 -- made to check the restriction No_Direct_Boolean_Operators.
98 -- Enforce the restrictions on the use of discriminants when constraining
99 -- a component of a discriminated type (record or concurrent type).
102 -- Given a node for an operator associated with type T, check that
103 -- the operator is visible. Operators all of whose operands are
104 -- universal must be checked for visibility during resolution
105 -- because their type is not determinable based on their operands.
108 -- Given a call node, N, which is known to occur immediately within the
109 -- subprogram being called, determines whether it is a detectable case of
110 -- an infinite recursion, and if so, outputs appropriate messages. Returns
111 -- True if an infinite recursion is detected, and False otherwise.
114 -- If the type of the object being initialized uses the secondary stack
115 -- directly or indirectly, create a transient scope for the call to the
116 -- init proc. This is because we do not create transient scopes for the
117 -- initialization of individual components within the init proc itself.
118 -- Could be optimized away perhaps?
121 -- Utility to check whether the name in the call is a predefined
122 -- operator, in which case the call is made into an operator node.
123 -- An instance of an intrinsic conversion operation may be given
124 -- an operator name, but is not treated like an operator.
127 -- If a default expression in entry call N depends on the discriminants
128 -- of the task, it must be replaced with a reference to the discriminant
129 -- of the task being called.
164 function Operator_Kind
168 -- Utility to map the name of an operator into the corresponding Node. Used
169 -- by other node rewriting procedures.
172 -- Resolve actuals of call, and add default expressions for missing ones.
175 -- Called from Resolve_Call, when the prefix denotes an entry or element
176 -- of entry family. Actuals are resolved as for subprograms, and the node
177 -- is rebuilt as an entry call. Also called for protected operations. Typ
178 -- is the context type, which is used when the operation is a protected
179 -- function with no arguments, and the return value is indexed.
182 -- A call to a user-defined intrinsic operator is rewritten as a call
183 -- to the corresponding predefined operator, with suitable conversions.
186 -- Ditto, for unary operators (only arithmetic ones).
189 -- If an operator node resolves to a call to a user-defined operator,
190 -- rewrite the node as a function call.
192 procedure Make_Call_Into_Operator
196 -- Inverse transformation: if an operator is given in functional notation,
197 -- then after resolving the node, transform into an operator node, so
198 -- that operands are resolved properly. Recall that predefined operators
199 -- do not have a full signature and special resolution rules apply.
202 -- An operator can rename another, e.g. in an instantiation. In that
203 -- case, the proper operator node must be constructed.
206 -- The String_Literal_Subtype is built for all strings that are not
207 -- operands of a static concatenation operation. If the argument is
208 -- not a N_String_Literal node, then the call has no effect.
211 -- Build subtype of array type, with the range specified by the slice
214 -- A universal_fixed expression in an universal context is unambiguous
215 -- if there is only one applicable fixed point type. Determining whether
216 -- there is only one requires a search over all visible entities, and
217 -- happens only in very pathological cases (see 6115-006).
219 function Valid_Conversion
224 -- Verify legality rules given in 4.6 (8-23). Target is the target
225 -- type of the conversion, which may be an implicit conversion of
226 -- an actual parameter to an anonymous access type (in which case
227 -- N denotes the actual parameter and N = Operand).
229 -------------------------
230 -- Ambiguous_Character --
231 -------------------------
236 begin
239 Error_Msg_N
254 -------------------------
255 -- Analyze_And_Resolve --
256 -------------------------
259 begin
265 begin
270 -- Version withs check(s) suppressed
272 procedure Analyze_And_Resolve
276 is
279 begin
281 declare
284 begin
290 else
291 declare
294 begin
302 and then Scope_Is_Transient
303 then
304 -- This can only happen if a transient scope was created
305 -- for an inner expression, which will be removed upon
306 -- completion of the analysis of an enclosing construct.
307 -- The transient scope must have the suppress status of
308 -- the enclosing environment, not of this Analyze call.
311 Scope_Suppress;
315 procedure Analyze_And_Resolve
318 is
321 begin
323 declare
326 begin
332 else
333 declare
336 begin
344 and then Scope_Is_Transient
345 then
347 Scope_Suppress;
351 -----------------------------
352 -- Check_Direct_Boolean_Op --
353 -----------------------------
356 begin
362 ----------------------------
363 -- Check_Discriminant_Use --
364 ----------------------------
372 begin
373 -- Any use in a default expression is legal.
380 -- Discriminant cannot be used to constrain a scalar type.
387 then
392 -- The following check catches the unusual case where
393 -- a discriminant appears within an index constraint
394 -- that is part of a larger expression within a constraint
395 -- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
396 -- For now we only check case of record components, and
397 -- note that a similar check should also apply in the
398 -- case of discriminant constraints below. ???
400 -- Note that the check for N_Subtype_Declaration below is to
401 -- detect the valid use of discriminants in the constraints of a
402 -- subtype declaration when this subtype declaration appears
403 -- inside the scope of a record type (which is syntactically
404 -- illegal, but which may be created as part of derived type
405 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
406 -- for more info.
410 and then not
412 and then
414 or else
417 then
418 Error_Msg_N
423 -- Detect a common beginner error:
425 -- type R (D : Positive := 100) is record
426 -- Name : String (1 .. D);
427 -- end record;
429 -- The default value causes an object of type R to be
430 -- allocated with room for Positive'Last characters.
432 declare
439 -- Return True if type T has a large enough range that
440 -- any array whose index type covered the whole range of
441 -- the type would likely raise Storage_Error.
443 ------------------------
444 -- Large_Storage_Type --
445 ------------------------
448 begin
449 return
450 T = Standard_Integer
451 or else
452 T = Standard_Positive
453 or else
457 begin
458 -- Check that the Disc has a large range
464 -- If the enclosing type is limited, we allocate only the
465 -- default value, not the maximum, and there is no need for
466 -- a warning.
472 -- Check that it is the high bound
476 then
480 -- Check the array allows a large range at this bound.
481 -- First find the array
495 -- Next, find the dimension
503 loop
512 -- Now, check the dimension has a large range
518 -- Warn about the danger
520 Error_Msg_N
530 -- Legal case is in index or discriminant constraint
534 then
536 Error_Msg_N
542 -- Otherwise, context is an expression. It should not be within
543 -- (i.e. a subexpression of) a constraint for a component.
545 else
552 loop
558 -- If the discriminant is used in an expression that is a bound
559 -- of a scalar type, an Itype is created and the bounds are attached
560 -- to its range, not to the original subtype indication. Such use
561 -- is of course a double fault.
564 and then
566 or else
570 -- The constraint itself may be given by a subtype indication,
571 -- rather than by a more common discrete range.
574 and then
578 then
579 Error_Msg_N
585 --------------------------------
586 -- Check_For_Visible_Operator --
587 --------------------------------
590 begin
592 Error_Msg_NE
598 ------------------------------
599 -- Check_Infinite_Recursion --
600 ------------------------------
607 -- Check whether list of actuals is identical to list of formals
608 -- of called function (which is also the enclosing scope).
610 ------------------------
611 -- Same_Argument_List --
612 ------------------------
619 begin
622 else
632 then
643 -- Start of processing for Check_Infinite_Recursion
645 begin
646 -- Loop moving up tree, quitting if something tells us we are
647 -- definitely not in an infinite recursion situation.
650 loop
658 then
663 then
664 -- If the call is the expression of a return statement and
665 -- the actuals are identical to the formals, it's worth a
666 -- warning. However, we skip this if there is an immediately
667 -- preceding raise statement, since the call is never executed.
669 -- Furthermore, this corresponds to a common idiom:
671 -- function F (L : Thing) return Boolean is
672 -- begin
673 -- raise Program_Error;
674 -- return F (L);
675 -- end F;
677 -- for generating a stub function
680 and then Same_Argument_List
681 then
684 and then
686 or else
692 else
703 -------------------------------
704 -- Check_Initialization_Call --
705 -------------------------------
711 -- Check whether the creation of an object of the type will involve
712 -- use of the secondary stack. If T is a record type, this is true
713 -- if the expression for some component uses the secondary stack, eg.
714 -- through a call to a function that returns an unconstrained value.
715 -- False if T is controlled, because cleanups occur elsewhere.
717 -------------
718 -- Uses_SS --
719 -------------
725 begin
739 then
742 -- The expression for a dynamic component may be
743 -- rewritten as a dereference. Retrieve original
744 -- call.
748 then
761 else
766 -- Start of processing for Check_Initialization_Call
768 begin
769 -- Nothing to do if functions do not use the secondary stack for
770 -- returns (i.e. they use a depressed stack pointer instead).
775 -- Otherwise establish a transient scope if the type needs it
782 ------------------------------
783 -- Check_Parameterless_Call --
784 ------------------------------
789 begin
790 -- Defend against junk stuff if errors already detected
797 then
804 -- If the context expects a value, and the name is a procedure,
805 -- this is most likely a missing 'Access. Do not try to resolve
806 -- the parameterless call, error will be caught when the outer
807 -- call is analyzed.
812 and then
816 then
820 -- Rewrite as call if overloadable entity that is (or could be, in
821 -- the overloaded case) a function call. If we know for sure that
822 -- the entity is an enumeration literal, we do not rewrite it.
829 -- Rewrite as call if it is an explicit deference of an expression of
830 -- a subprogram access type, and the suprogram type is not that of a
831 -- procedure or entry.
833 or else
838 -- Rewrite as call if it is a selected component which is a function,
839 -- this is the case of a call to a protected function (which may be
840 -- overloaded with other protected operations).
842 or else
845 or else
847 or else
851 -- If one of the above three conditions is met, rewrite as call.
852 -- Apply the rewriting only once.
854 then
857 then
860 -- If overloaded, overload set belongs to new copy.
864 -- Change node to parameterless function call (note that the
865 -- Parameter_Associations associations field is left set to Empty,
866 -- its normal default value since there are no parameters)
879 ----------------------
880 -- Is_Predefined_Op --
881 ----------------------
884 begin
892 -----------------------------
893 -- Make_Call_Into_Operator --
894 -----------------------------
896 procedure Make_Call_Into_Operator
900 is
915 -- Determine whether E is an access type declared by an access decla-
916 -- ration, and not an (anonymous) allocator type.
919 -- If the operand is not universal, and the operator is given by a
920 -- expanded name, verify that the operand has an interpretation with
921 -- a type defined in the given scope of the operator.
924 -- Find a type of the given class in the package Pack that contains
925 -- the operator.
927 -----------------------------
928 -- Is_Definite_Access_Type --
929 -----------------------------
933 begin
939 ---------------------------
940 -- Operand_Type_In_Scope --
941 ---------------------------
948 begin
952 else
968 ---------------
969 -- Type_In_P --
970 ---------------
976 -- Verify that node is not part of the type declaration for the
977 -- candidate type, which would otherwise be invisible.
979 -------------
980 -- In_Decl --
981 -------------
987 begin
996 else
999 loop
1002 else
1011 -- Start of processing for Type_In_P
1013 begin
1014 -- If the context type is declared in the prefix package, this
1015 -- is the desired base type.
1019 then
1022 else
1028 and then not In_Decl
1029 then
1040 -- Start of processing for Make_Call_Into_Operator
1042 begin
1045 -- Binary operator
1055 -- Unary operator
1057 else
1063 -- If the operator is denoted by an expanded name, and the prefix is
1064 -- not Standard, but the operator is a predefined one whose scope is
1065 -- Standard, then this is an implicit_operator, inserted as an
1066 -- interpretation by the procedure of the same name. This procedure
1067 -- overestimates the presence of implicit operators, because it does
1068 -- not examine the type of the operands. Verify now that the operand
1069 -- type appears in the given scope. If right operand is universal,
1070 -- check the other operand. In the case of concatenation, either
1071 -- argument can be the component type, so check the type of the result.
1072 -- If both arguments are literals, look for a type of the right kind
1073 -- defined in the given scope. This elaborate nonsense is brought to
1074 -- you courtesy of b33302a. The type itself must be frozen, so we must
1075 -- find the type of the proper class in the given scope.
1077 -- A final wrinkle is the multiplication operator for fixed point
1078 -- types, which is defined in Standard only, and not in the scope of
1079 -- the fixed_point type itself.
1084 -- If the entity being called is defined in the given package,
1085 -- it is a renaming of a predefined operator, and known to be
1086 -- legal.
1090 then
1097 then
1102 else
1111 and then Is_Binary
1113 then
1119 -- Verify that the scope contains a type that corresponds to
1120 -- the given literal. Optimize the case where Pack is Standard.
1142 else
1151 else
1160 then
1163 -- If the type is defined elsewhere, and the operator is not
1164 -- defined in the given scope (by a renaming declaration, e.g.)
1165 -- then this is an error as well. If an extension of System is
1166 -- present, and the type may be defined there, Pack must be
1167 -- System itself.
1174 then
1179 then
1186 Error_Msg_NE
1197 else
1201 -- If this is a call to a function that renames a predefined equality,
1202 -- the renaming declaration provides a type that must be used to
1203 -- resolve the operands. This must be done now because resolution of
1204 -- the equality node will not resolve any remaining ambiguity, and it
1205 -- assumes that the first operand is not overloaded.
1210 then
1219 -- If this is an arithmetic operator and the result type is private,
1220 -- the operands and the result must be wrapped in conversion to
1221 -- expose the underlying numeric type and expand the proper checks,
1222 -- e.g. on division.
1226 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1227 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1236 else
1240 -- For predefined operators on literals, the operation freezes
1241 -- their type.
1249 -------------------
1250 -- Operator_Kind --
1251 -------------------
1253 function Operator_Kind
1256 return Node_Kind
1257 is
1260 begin
1279 else
1283 -- Unary operators
1285 else
1290 else
1298 -----------------------------
1299 -- Pre_Analyze_And_Resolve --
1300 -----------------------------
1305 begin
1309 -- We suppress all checks for this analysis, since the checks will
1310 -- be applied properly, and in the right location, when the default
1311 -- expression is reanalyzed and reexpanded later on.
1315 Expander_Mode_Restore;
1319 -- Version without context type.
1324 begin
1331 Expander_Mode_Restore;
1335 ----------------------------------
1336 -- Replace_Actual_Discriminants --
1337 ----------------------------------
1345 -------------------
1346 -- Process_Discr --
1347 -------------------
1352 begin
1358 then
1374 -- Start of processing for Replace_Actual_Discriminants
1376 begin
1390 else
1395 -------------
1396 -- Resolve --
1397 -------------
1412 -- Try and fix up a literal so that it matches its expected type. New
1413 -- literals are manufactured if necessary to avoid cascaded errors.
1416 -- Called when attempt at resolving current expression fails
1418 --------------------
1419 -- Patch_Up_Value --
1420 --------------------
1423 begin
1426 then
1435 then
1443 then
1454 then
1465 -----------------------
1466 -- Resolution_Failed --
1467 -----------------------
1470 begin
1476 -- The caller will return without calling the expander, so we need
1477 -- to set the analyzed flag. Note that it is fine to set Analyzed
1478 -- to True even if we are in the middle of a shallow analysis,
1479 -- (see the spec of sem for more details) since this is an error
1480 -- situation anyway, and there is no point in repeating the
1481 -- analysis later (indeed it won't work to repeat it later, since
1482 -- we haven't got a clear resolution of which entity is being
1483 -- referenced.)
1489 -- Start of processing for Resolve
1491 begin
1496 -- Access attribute on remote subprogram cannot be used for
1497 -- a non-remote access-to-subprogram type.
1508 then
1509 Error_Msg_N
1513 -- If the context is a Remote_Access_To_Subprogram, access attributes
1514 -- must be resolved with the corresponding fat pointer. There is no need
1515 -- to check for the attribute name since the return type of an
1516 -- attribute is never a remote type.
1522 then
1523 declare
1531 begin
1532 -- Check that Typ is a fat pointer with a reference to a RAS as
1533 -- original access type.
1535 if
1538 or else
1542 then
1543 -- Prefix (N) must statically denote a remote subprogram
1544 -- declared in a package specification.
1561 or else
1563 then
1565 Error_Msg_N
1567 N);
1571 -- If we are generating code for a distributed program.
1572 -- perform semantic checks against the corresponding
1573 -- remote entities.
1578 and then Expander_Active
1579 then
1580 Check_Subtype_Conformant
1582 Old_Id => Designated_Type
1602 then
1607 -- Return if already analyzed
1613 -- Return if type = Any_Type (previous error encountered)
1622 -- If not overloaded, then we know the type, and all that needs doing
1623 -- is to check that this type is compatible with the context.
1629 -- In the overloaded case, we must select the interpretation that
1630 -- is compatible with the context (i.e. the type passed to Resolve)
1632 else
1635 -- Loop through possible interpretations
1639 -- We are only interested in interpretations that are compatible
1640 -- with the expected type, any other interpretations are ignored
1645 Write_Eol;
1648 else
1649 -- First matching interpretation
1657 -- Matching interpretation that is not the first, maybe an
1658 -- error, but there are some cases where preference rules are
1659 -- used to choose between the two possibilities. These and
1660 -- some more obscure cases are handled in Disambiguate.
1662 else
1666 -- Disambiguation has succeeded. Skip the remaining
1667 -- interpretations.
1677 else
1678 -- Before we issue an ambiguity complaint, check for
1679 -- the case of a subprogram call where at least one
1680 -- of the arguments is Any_Type, and if so, suppress
1681 -- the message, since it is a cascaded error.
1685 then
1686 declare
1690 begin
1701 Write_Eol;
1714 then
1719 then
1723 -- Not that special case, so issue message using the
1724 -- flag Ambiguous to control printing of the header
1725 -- message only at the start of an ambiguous set.
1728 Error_Msg_NE
1732 Error_Msg_N
1739 -- By default, the error message refers to the candidate
1740 -- interpretation. But if it is a predefined operator,
1741 -- it is implicitly declared at the declaration of
1742 -- the type of the operand. Recover the sloc of that
1743 -- declaration for the error message.
1749 /= Standard_Standard
1750 then
1755 then
1763 /= Standard_Standard
1764 then
1769 then
1772 else
1779 then
1780 Error_Msg_N
1782 else
1789 -- We have a matching interpretation, Expr_Type is the
1790 -- type from this interpretation, and Seen is the entity.
1792 -- For an operator, just set the entity name. The type will
1793 -- be set by the specific operator resolution routine.
1802 -- For an explicit dereference, attribute reference, range,
1803 -- short-circuit form (which is not an operator node),
1804 -- or a call with a name that is an explicit dereference,
1805 -- there is nothing to be done at this point.
1816 then
1819 -- For procedure or function calls, set the type of the
1820 -- name, and also the entity pointer for the prefix
1826 then
1833 then
1838 -- For all other cases, just set the type of the Name
1840 else
1846 -- Move to next interpretation
1854 -- At this stage Found indicates whether or not an acceptable
1855 -- interpretation exists. If not, then we have an error, except
1856 -- that if the context is Any_Type as a result of some other error,
1857 -- then we suppress the error report.
1862 -- If type we are looking for is Void, then this is the
1863 -- procedure call case, and the error is simply that what
1864 -- we gave is not a procedure name (we think of procedure
1865 -- calls as expressions with types internally, but the user
1866 -- doesn't think of them this way!)
1870 -- Special case message if function used as a procedure
1875 then
1876 Error_Msg_NE
1880 -- Otherwise give general message (not clear what cases
1881 -- this covers, but no harm in providing for them!)
1883 else
1889 -- Otherwise we do have a subexpression with the wrong type
1891 -- Check for the case of an allocator which uses an access
1892 -- type instead of the designated type. This is a common
1893 -- error and we specialize the message, posting an error
1894 -- on the operand of the allocator, complaining that we
1895 -- expected the designated type of the allocator.
1901 then
1905 -- Check for view mismatch on Null in instances, for
1906 -- which the view-swapping mechanism has no identifier.
1912 then
1917 -- Check for an aggregate. Sometimes we can get bogus
1918 -- aggregates from misuse of parentheses, and we are
1919 -- about to complain about the aggregate without even
1920 -- looking inside it.
1922 -- Instead, if we have an aggregate of type Any_Composite,
1923 -- then analyze and resolve the component fields, and then
1924 -- only issue another message if we get no errors doing
1925 -- this (otherwise assume that the errors in the aggregate
1926 -- caused the problem).
1930 then
1931 -- Disable expansion in any case. If there is a type mismatch
1932 -- it may be fatal to try to expand the aggregate. The flag
1933 -- would otherwise be set to false when the error is posted.
1937 declare
1939 -- Check one aggregate, and set Found to True if we
1940 -- have a definite error in any of its elements
1943 -- Check one element of aggregate and set Found to
1944 -- True if we definitely have an error in the element.
1949 begin
1967 ----------------
1968 -- Check_Elmt --
1969 ----------------
1972 begin
1973 -- If we have a nested aggregate, go inside it (to
1974 -- attempt a naked analyze-resolve of the aggregate
1975 -- can cause undesirable cascaded errors). Do not
1976 -- resolve expression if it needs a type from context,
1977 -- as for integer * fixed expression.
1982 else
1987 then
1997 begin
2002 -- If an error message was issued already, Found got reset
2003 -- to True, so if it is still False, issue the standard
2004 -- Wrong_Type message.
2009 then
2010 declare
2012 begin
2018 -- Protected operation: retrieve operation name.
2021 else
2031 declare
2035 begin
2049 else
2052 else
2058 Resolution_Failed;
2061 -- Test if we have more than one interpretation for the context
2064 Resolution_Failed;
2067 -- Here we have an acceptable interpretation for the context
2069 else
2070 -- A user-defined operator is tranformed into a function call at
2071 -- this point, so that further processing knows that operators are
2072 -- really operators (i.e. are predefined operators). User-defined
2073 -- operators that are intrinsic are just renamings of the predefined
2074 -- ones, and need not be turned into calls either, but if they rename
2075 -- a different operator, we must transform the node accordingly.
2076 -- Instantiations of Unchecked_Conversion are intrinsic but are
2077 -- treated as functions, even if given an operator designator.
2082 then
2092 -- Propagate type information and normalize tree for various
2093 -- predefined operations. If the context only imposes a class of
2094 -- types, rather than a specific type, propagate the actual type
2095 -- downward.
2102 then
2105 -- Any_Fixed is legal in a real context only if a specific
2106 -- fixed point type is imposed. If Norman Cohen can be
2107 -- confused by this, it deserves a separate message.
2111 then
2120 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2122 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2124 when N_And_Then | N_Or_Else
2125 => Resolve_Short_Circuit (N, Ctx_Type);
2127 when N_Attribute_Reference
2128 => Resolve_Attribute (N, Ctx_Type);
2130 when N_Character_Literal
2131 => Resolve_Character_Literal (N, Ctx_Type);
2133 when N_Conditional_Expression
2134 => Resolve_Conditional_Expression (N, Ctx_Type);
2136 when N_Expanded_Name
2137 => Resolve_Entity_Name (N, Ctx_Type);
2139 when N_Extension_Aggregate
2140 => Resolve_Extension_Aggregate (N, Ctx_Type);
2142 when N_Explicit_Dereference
2143 => Resolve_Explicit_Dereference (N, Ctx_Type);
2145 when N_Function_Call
2146 => Resolve_Call (N, Ctx_Type);
2148 when N_Identifier
2149 => Resolve_Entity_Name (N, Ctx_Type);
2151 when N_In | N_Not_In
2152 => Resolve_Membership_Op (N, Ctx_Type);
2154 when N_Indexed_Component
2155 => Resolve_Indexed_Component (N, Ctx_Type);
2157 when N_Integer_Literal
2158 => Resolve_Integer_Literal (N, Ctx_Type);
2160 when N_Null => Resolve_Null (N, Ctx_Type);
2162 when N_Op_And | N_Op_Or | N_Op_Xor
2163 => Resolve_Logical_Op (N, Ctx_Type);
2165 when N_Op_Eq | N_Op_Ne
2166 => Resolve_Equality_Op (N, Ctx_Type);
2168 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2169 => Resolve_Comparison_Op (N, Ctx_Type);
2171 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2173 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2174 N_Op_Divide | N_Op_Mod | N_Op_Rem
2176 => Resolve_Arithmetic_Op (N, Ctx_Type);
2178 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2180 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2182 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2183 => Resolve_Unary_Op (N, Ctx_Type);
2185 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2187 when N_Procedure_Call_Statement
2188 => Resolve_Call (N, Ctx_Type);
2190 when N_Operator_Symbol
2191 => Resolve_Operator_Symbol (N, Ctx_Type);
2193 when N_Qualified_Expression
2194 => Resolve_Qualified_Expression (N, Ctx_Type);
2196 when N_Raise_xxx_Error
2197 => Set_Etype (N, Ctx_Type);
2199 when N_Range => Resolve_Range (N, Ctx_Type);
2201 when N_Real_Literal
2202 => Resolve_Real_Literal (N, Ctx_Type);
2204 when N_Reference => Resolve_Reference (N, Ctx_Type);
2206 when N_Selected_Component
2207 => Resolve_Selected_Component (N, Ctx_Type);
2209 when N_Slice => Resolve_Slice (N, Ctx_Type);
2211 when N_String_Literal
2212 => Resolve_String_Literal (N, Ctx_Type);
2214 when N_Subprogram_Info
2215 => Resolve_Subprogram_Info (N, Ctx_Type);
2217 when N_Type_Conversion
2218 => Resolve_Type_Conversion (N, Ctx_Type);
2220 when N_Unchecked_Expression =>
2221 Resolve_Unchecked_Expression (N, Ctx_Type);
2223 when N_Unchecked_Type_Conversion =>
2224 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2226 end case;
2228 -- If the subexpression was replaced by a non-subexpression, then
2229 -- all we do is to expand it. The only legitimate case we know of
2230 -- is converting procedure call statement to entry call statements,
2231 -- but there may be others, so we are making this test general.
2233 if Nkind (N) not in N_Subexpr then
2234 Debug_A_Exit ("resolving ", N, " (done)");
2235 Expand (N);
2236 return;
2237 end if;
2239 -- The expression is definitely NOT overloaded at this point, so
2240 -- we reset the Is_Overloaded flag to avoid any confusion when
2241 -- reanalyzing the node.
2243 Set_Is_Overloaded (N, False);
2245 -- Freeze expression type, entity if it is a name, and designated
2246 -- type if it is an allocator (RM 13.14(10,11,13)).
2248 -- Now that the resolution of the type of the node is complete,
2249 -- and we did not detect an error, we can expand this node. We
2250 -- skip the expand call if we are in a default expression, see
2251 -- section "Handling of Default Expressions" in Sem spec.
2253 Debug_A_Exit ("resolving ", N, " (done)");
2255 -- We unconditionally freeze the expression, even if we are in
2256 -- default expression mode (the Freeze_Expression routine tests
2257 -- this flag and only freezes static types if it is set).
2259 Freeze_Expression (N);
2261 -- Now we can do the expansion
2263 Expand (N);
2264 end if;
2265 end Resolve;
2267 -------------
2268 -- Resolve --
2269 -------------
2271 -- Version with check(s) suppressed
2273 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2274 begin
2275 if Suppress = All_Checks then
2276 declare
2277 Svg : constant Suppress_Array := Scope_Suppress;
2279 begin
2280 Scope_Suppress := (others => True);
2281 Resolve (N, Typ);
2282 Scope_Suppress := Svg;
2283 end;
2285 else
2286 declare
2287 Svg : constant Boolean := Scope_Suppress (Suppress);
2289 begin
2290 Scope_Suppress (Suppress) := True;
2291 Resolve (N, Typ);
2292 Scope_Suppress (Suppress) := Svg;
2293 end;
2294 end if;
2295 end Resolve;
2297 -------------
2298 -- Resolve --
2299 -------------
2301 -- Version with implicit type
2303 procedure Resolve (N : Node_Id) is
2304 begin
2305 Resolve (N, Etype (N));
2306 end Resolve;
2308 ---------------------
2309 -- Resolve_Actuals --
2310 ---------------------
2312 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2313 Loc : constant Source_Ptr := Sloc (N);
2314 A : Node_Id;
2315 F : Entity_Id;
2316 A_Typ : Entity_Id;
2317 F_Typ : Entity_Id;
2318 Prev : Node_Id := Empty;
2320 procedure Insert_Default;
2321 -- If the actual is missing in a call, insert in the actuals list
2322 -- an instance of the default expression. The insertion is always
2323 -- a named association.
2325 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean;
2326 -- Check whether T1 and T2, or their full views, are derived from a
2327 -- common type. Used to enforce the restrictions on array conversions
2328 -- of AI95-00246.
2330 --------------------
2331 -- Insert_Default --
2332 --------------------
2334 procedure Insert_Default is
2335 Actval : Node_Id;
2336 Assoc : Node_Id;
2338 begin
2339 -- Missing argument in call, nothing to insert
2341 if No (Default_Value (F)) then
2342 return;
2344 else
2345 -- Note that we do a full New_Copy_Tree, so that any associated
2346 -- Itypes are properly copied. This may not be needed any more,
2347 -- but it does no harm as a safety measure! Defaults of a generic
2348 -- formal may be out of bounds of the corresponding actual (see
2349 -- cc1311b) and an additional check may be required.
2351 Actval := New_Copy_Tree (Default_Value (F),
2352 New_Scope => Current_Scope, New_Sloc => Loc);
2354 if Is_Concurrent_Type (Scope (Nam))
2355 and then Has_Discriminants (Scope (Nam))
2356 then
2357 Replace_Actual_Discriminants (N, Actval);
2358 end if;
2360 if Is_Overloadable (Nam)
2361 and then Present (Alias (Nam))
2362 then
2363 if Base_Type (Etype (F)) /= Base_Type (Etype (Actval))
2364 and then not Is_Tagged_Type (Etype (F))
2365 then
2366 -- If default is a real literal, do not introduce a
2367 -- conversion whose effect may depend on the run-time
2368 -- size of universal real.
2370 if Nkind (Actval) = N_Real_Literal then
2371 Set_Etype (Actval, Base_Type (Etype (F)));
2372 else
2373 Actval := Unchecked_Convert_To (Etype (F), Actval);
2374 end if;
2375 end if;
2377 if Is_Scalar_Type (Etype (F)) then
2378 Enable_Range_Check (Actval);
2379 end if;
2381 Set_Parent (Actval, N);
2383 -- Resolve aggregates with their base type, to avoid scope
2384 -- anomalies: the subtype was first built in the suprogram
2385 -- declaration, and the current call may be nested.
2387 if Nkind (Actval) = N_Aggregate
2388 and then Has_Discriminants (Etype (Actval))
2389 then
2390 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
2391 else
2392 Analyze_And_Resolve (Actval, Etype (Actval));
2393 end if;
2395 else
2396 Set_Parent (Actval, N);
2398 -- See note above concerning aggregates.
2400 if Nkind (Actval) = N_Aggregate
2401 and then Has_Discriminants (Etype (Actval))
2402 then
2403 Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
2405 -- Resolve entities with their own type, which may differ
2406 -- from the type of a reference in a generic context (the
2407 -- view swapping mechanism did not anticipate the re-analysis
2408 -- of default values in calls).
2410 elsif Is_Entity_Name (Actval) then
2411 Analyze_And_Resolve (Actval, Etype (Entity (Actval)));
2413 else
2414 Analyze_And_Resolve (Actval, Etype (Actval));
2415 end if;
2416 end if;
2418 -- If default is a tag indeterminate function call, propagate
2419 -- tag to obtain proper dispatching.
2421 if Is_Controlling_Formal (F)
2422 and then Nkind (Default_Value (F)) = N_Function_Call
2423 then
2424 Set_Is_Controlling_Actual (Actval);
2425 end if;
2427 end if;
2429 -- If the default expression raises constraint error, then just
2430 -- silently replace it with an N_Raise_Constraint_Error node,
2431 -- since we already gave the warning on the subprogram spec.
2433 if Raises_Constraint_Error (Actval) then
2434 Rewrite (Actval,
2435 Make_Raise_Constraint_Error (Loc,
2436 Reason => CE_Range_Check_Failed));
2437 Set_Raises_Constraint_Error (Actval);
2438 Set_Etype (Actval, Etype (F));
2439 end if;
2441 Assoc :=
2442 Make_Parameter_Association (Loc,
2443 Explicit_Actual_Parameter => Actval,
2444 Selector_Name => Make_Identifier (Loc, Chars (F)));
2446 -- Case of insertion is first named actual
2448 if No (Prev) or else
2449 Nkind (Parent (Prev)) /= N_Parameter_Association
2450 then
2451 Set_Next_Named_Actual (Assoc, First_Named_Actual (N));
2452 Set_First_Named_Actual (N, Actval);
2454 if No (Prev) then
2455 if not Present (Parameter_Associations (N)) then
2456 Set_Parameter_Associations (N, New_List (Assoc));
2457 else
2458 Append (Assoc, Parameter_Associations (N));
2459 end if;
2461 else
2462 Insert_After (Prev, Assoc);
2463 end if;
2465 -- Case of insertion is not first named actual
2467 else
2468 Set_Next_Named_Actual
2469 (Assoc, Next_Named_Actual (Parent (Prev)));
2470 Set_Next_Named_Actual (Parent (Prev), Actval);
2471 Append (Assoc, Parameter_Associations (N));
2472 end if;
2474 Mark_Rewrite_Insertion (Assoc);
2475 Mark_Rewrite_Insertion (Actval);
2477 Prev := Actval;
2478 end Insert_Default;
2480 -------------------
2481 -- Same_Ancestor --
2482 -------------------
2484 function Same_Ancestor (T1, T2 : Entity_Id) return Boolean is
2485 FT1 : Entity_Id := T1;
2486 FT2 : Entity_Id := T2;
2488 begin
2489 if Is_Private_Type (T1)
2490 and then Present (Full_View (T1))
2491 then
2492 FT1 := Full_View (T1);
2493 end if;
2495 if Is_Private_Type (T2)
2496 and then Present (Full_View (T2))
2497 then
2498 FT2 := Full_View (T2);
2499 end if;
2501 return Root_Type (Base_Type (FT1)) = Root_Type (Base_Type (FT2));
2502 end Same_Ancestor;
2504 -- Start of processing for Resolve_Actuals
2506 begin
2507 A := First_Actual (N);
2508 F := First_Formal (Nam);
2510 while Present (F) loop
2511 if No (A) and then Needs_No_Actuals (Nam) then
2512 null;
2514 -- If we have an error in any actual or formal, indicated by
2515 -- a type of Any_Type, then abandon resolution attempt, and
2516 -- set result type to Any_Type.
2518 elsif (Present (A) and then Etype (A) = Any_Type)
2519 or else Etype (F) = Any_Type
2520 then
2521 Set_Etype (N, Any_Type);
2522 return;
2523 end if;
2525 if Present (A)
2526 and then (Nkind (Parent (A)) /= N_Parameter_Association
2527 or else
2528 Chars (Selector_Name (Parent (A))) = Chars (F))
2529 then
2530 -- If the formal is Out or In_Out, do not resolve and expand the
2531 -- conversion, because it is subsequently expanded into explicit
2532 -- temporaries and assignments. However, the object of the
2533 -- conversion can be resolved. An exception is the case of
2534 -- a tagged type conversion with a class-wide actual. In that
2535 -- case we want the tag check to occur and no temporary will
2536 -- will be needed (no representation change can occur) and
2537 -- the parameter is passed by reference, so we go ahead and
2538 -- resolve the type conversion.
2540 if Ekind (F) /= E_In_Parameter
2541 and then Nkind (A) = N_Type_Conversion
2542 and then not Is_Class_Wide_Type (Etype (Expression (A)))
2543 then
2544 if Ekind (F) = E_In_Out_Parameter
2545 and then Is_Array_Type (Etype (F))
2546 then
2547 if Has_Aliased_Components (Etype (Expression (A)))
2548 /= Has_Aliased_Components (Etype (F))
2549 then
2550 Error_Msg_N
2551 ("both component types in a view conversion must be"
2552 & " aliased, or neither", A);
2554 elsif not Same_Ancestor (Etype (F), Etype (Expression (A)))
2555 and then
2556 (Is_By_Reference_Type (Etype (F))
2557 or else Is_By_Reference_Type (Etype (Expression (A))))
2558 then
2559 Error_Msg_N
2560 ("view conversion between unrelated by_reference "
2562 end if;
2563 end if;
2565 if Conversion_OK (A)
2566 or else Valid_Conversion (A, Etype (A), Expression (A))
2567 then
2568 Resolve (Expression (A));
2569 end if;
2571 else
2572 if Nkind (A) = N_Type_Conversion
2573 and then Is_Array_Type (Etype (F))
2574 and then not Same_Ancestor (Etype (F), Etype (Expression (A)))
2575 and then
2576 (Is_Limited_Type (Etype (F))
2577 or else Is_Limited_Type (Etype (Expression (A))))
2578 then
2579 Error_Msg_N
2580 ("Conversion between unrelated limited array types "
2583 -- Disable explanation (which produces additional errors)
2584 -- until AI is approved and warning becomes an error.
2586 -- if Is_Limited_Type (Etype (F)) then
2587 -- Explain_Limited_Type (Etype (F), A);
2588 -- end if;
2590 -- if Is_Limited_Type (Etype (Expression (A))) then
2591 -- Explain_Limited_Type (Etype (Expression (A)), A);
2592 -- end if;
2593 end if;
2595 Resolve (A, Etype (F));
2596 end if;
2598 A_Typ := Etype (A);
2599 F_Typ := Etype (F);
2601 -- Perform error checks for IN and IN OUT parameters
2603 if Ekind (F) /= E_Out_Parameter then
2605 -- Check unset reference. For scalar parameters, it is clearly
2606 -- wrong to pass an uninitialized value as either an IN or
2607 -- IN-OUT parameter. For composites, it is also clearly an
2608 -- error to pass a completely uninitialized value as an IN
2609 -- parameter, but the case of IN OUT is trickier. We prefer
2610 -- not to give a warning here. For example, suppose there is
2611 -- a routine that sets some component of a record to False.
2612 -- It is perfectly reasonable to make this IN-OUT and allow
2613 -- either initialized or uninitialized records to be passed
2614 -- in this case.
2616 -- For partially initialized composite values, we also avoid
2617 -- warnings, since it is quite likely that we are passing a
2618 -- partially initialized value and only the initialized fields
2619 -- will in fact be read in the subprogram.
2621 if Is_Scalar_Type (A_Typ)
2622 or else (Ekind (F) = E_In_Parameter
2623 and then not Is_Partially_Initialized_Type (A_Typ))
2624 then
2625 Check_Unset_Reference (A);
2626 end if;
2628 -- In Ada 83 we cannot pass an OUT parameter as an IN
2629 -- or IN OUT actual to a nested call, since this is a
2630 -- case of reading an out parameter, which is not allowed.
2632 if Ada_83
2633 and then Is_Entity_Name (A)
2634 and then Ekind (Entity (A)) = E_Out_Parameter
2635 then
2636 Error_Msg_N ("(Ada 83) illegal reading of out parameter", A);
2637 end if;
2638 end if;
2640 if Ekind (F) /= E_In_Parameter
2641 and then not Is_OK_Variable_For_Out_Formal (A)
2642 then
2643 Error_Msg_NE ("actual for& must be a variable", A, F);
2645 if Is_Entity_Name (A) then
2646 Kill_Checks (Entity (A));
2647 else
2648 Kill_All_Checks;
2649 end if;
2650 end if;
2652 if Etype (A) = Any_Type then
2653 Set_Etype (N, Any_Type);
2654 return;
2655 end if;
2657 -- Apply appropriate range checks for in, out, and in-out
2658 -- parameters. Out and in-out parameters also need a separate
2659 -- check, if there is a type conversion, to make sure the return
2660 -- value meets the constraints of the variable before the
2661 -- conversion.
2663 -- Gigi looks at the check flag and uses the appropriate types.
2664 -- For now since one flag is used there is an optimization which
2665 -- might not be done in the In Out case since Gigi does not do
2666 -- any analysis. More thought required about this ???
2668 if Ekind (F) = E_In_Parameter
2669 or else Ekind (F) = E_In_Out_Parameter
2670 then
2671 if Is_Scalar_Type (Etype (A)) then
2672 Apply_Scalar_Range_Check (A, F_Typ);
2674 elsif Is_Array_Type (Etype (A)) then
2675 Apply_Length_Check (A, F_Typ);
2677 elsif Is_Record_Type (F_Typ)
2678 and then Has_Discriminants (F_Typ)
2679 and then Is_Constrained (F_Typ)
2680 and then (not Is_Derived_Type (F_Typ)
2681 or else Comes_From_Source (Nam))
2682 then
2683 Apply_Discriminant_Check (A, F_Typ);
2685 elsif Is_Access_Type (F_Typ)
2686 and then Is_Array_Type (Designated_Type (F_Typ))
2687 and then Is_Constrained (Designated_Type (F_Typ))
2688 then
2689 Apply_Length_Check (A, F_Typ);
2691 elsif Is_Access_Type (F_Typ)
2692 and then Has_Discriminants (Designated_Type (F_Typ))
2693 and then Is_Constrained (Designated_Type (F_Typ))
2694 then
2695 Apply_Discriminant_Check (A, F_Typ);
2697 else
2698 Apply_Range_Check (A, F_Typ);
2699 end if;
2701 -- Ada 0Y (AI-231)
2703 if Extensions_Allowed
2704 and then Is_Access_Type (F_Typ)
2705 and then (Can_Never_Be_Null (F)
2706 or else Can_Never_Be_Null (F_Typ))
2707 then
2708 if Nkind (A) = N_Null then
2709 Error_Msg_NE ("(Ada 0Y) not allowed for null-exclusion " &
2710 "formal", A, F_Typ);
2711 end if;
2712 end if;
2713 end if;
2715 if Ekind (F) = E_Out_Parameter
2716 or else Ekind (F) = E_In_Out_Parameter
2717 then
2718 if Nkind (A) = N_Type_Conversion then
2719 if Is_Scalar_Type (A_Typ) then
2720 Apply_Scalar_Range_Check
2721 (Expression (A), Etype (Expression (A)), A_Typ);
2722 else
2723 Apply_Range_Check
2724 (Expression (A), Etype (Expression (A)), A_Typ);
2725 end if;
2727 else
2728 if Is_Scalar_Type (F_Typ) then
2729 Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
2731 elsif Is_Array_Type (F_Typ)
2732 and then Ekind (F) = E_Out_Parameter
2733 then
2734 Apply_Length_Check (A, F_Typ);
2736 else
2737 Apply_Range_Check (A, A_Typ, F_Typ);
2738 end if;
2739 end if;
2740 end if;
2742 -- An actual associated with an access parameter is implicitly
2743 -- converted to the anonymous access type of the formal and
2744 -- must satisfy the legality checks for access conversions.
2746 if Ekind (F_Typ) = E_Anonymous_Access_Type then
2747 if not Valid_Conversion (A, F_Typ, A) then
2748 Error_Msg_N
2749 ("invalid implicit conversion for access parameter", A);
2750 end if;
2751 end if;
2753 -- Check bad case of atomic/volatile argument (RM C.6(12))
2755 if Is_By_Reference_Type (Etype (F))
2756 and then Comes_From_Source (N)
2757 then
2758 if Is_Atomic_Object (A)
2759 and then not Is_Atomic (Etype (F))
2760 then
2761 Error_Msg_N
2762 ("cannot pass atomic argument to non-atomic formal",
2763 N);
2765 elsif Is_Volatile_Object (A)
2766 and then not Is_Volatile (Etype (F))
2767 then
2768 Error_Msg_N
2769 ("cannot pass volatile argument to non-volatile formal",
2770 N);
2771 end if;
2772 end if;
2774 -- Check that subprograms don't have improper controlling
2775 -- arguments (RM 3.9.2 (9))
2777 if Is_Controlling_Formal (F) then
2778 Set_Is_Controlling_Actual (A);
2779 elsif Nkind (A) = N_Explicit_Dereference then
2780 Validate_Remote_Access_To_Class_Wide_Type (A);
2781 end if;
2783 if (Is_Class_Wide_Type (A_Typ) or else Is_Dynamically_Tagged (A))
2784 and then not Is_Class_Wide_Type (F_Typ)
2785 and then not Is_Controlling_Formal (F)
2786 then
2787 Error_Msg_N ("class-wide argument not allowed here!", A);
2789 if Is_Subprogram (Nam)
2790 and then Comes_From_Source (Nam)
2791 then
2792 Error_Msg_Node_2 := F_Typ;
2793 Error_Msg_NE
2794 ("& is not a primitive operation of &!", A, Nam);
2795 end if;
2797 elsif Is_Access_Type (A_Typ)
2798 and then Is_Access_Type (F_Typ)
2799 and then Ekind (F_Typ) /= E_Access_Subprogram_Type
2800 and then (Is_Class_Wide_Type (Designated_Type (A_Typ))
2801 or else (Nkind (A) = N_Attribute_Reference
2802 and then
2803 Is_Class_Wide_Type (Etype (Prefix (A)))))
2804 and then not Is_Class_Wide_Type (Designated_Type (F_Typ))
2805 and then not Is_Controlling_Formal (F)
2806 then
2807 Error_Msg_N
2808 ("access to class-wide argument not allowed here!", A);
2810 if Is_Subprogram (Nam)
2811 and then Comes_From_Source (Nam)
2812 then
2813 Error_Msg_Node_2 := Designated_Type (F_Typ);
2814 Error_Msg_NE
2815 ("& is not a primitive operation of &!", A, Nam);
2816 end if;
2817 end if;
2819 Eval_Actual (A);
2821 -- If it is a named association, treat the selector_name as
2822 -- a proper identifier, and mark the corresponding entity.
2824 if Nkind (Parent (A)) = N_Parameter_Association then
2825 Set_Entity (Selector_Name (Parent (A)), F);
2826 Generate_Reference (F, Selector_Name (Parent (A)));
2827 Set_Etype (Selector_Name (Parent (A)), F_Typ);
2829 end if;
2831 Prev := A;
2833 if Ekind (F) /= E_Out_Parameter then
2834 Check_Unset_Reference (A);
2835 end if;
2837 Next_Actual (A);
2839 -- Case where actual is not present
2841 else
2842 Insert_Default;
2843 end if;
2845 Next_Formal (F);
2846 end loop;
2847 end Resolve_Actuals;
2849 -----------------------
2850 -- Resolve_Allocator --
2851 -----------------------
2853 procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id) is
2854 E : constant Node_Id := Expression (N);
2855 Subtyp : Entity_Id;
2856 Discrim : Entity_Id;
2857 Constr : Node_Id;
2858 Disc_Exp : Node_Id;
2860 function In_Dispatching_Context return Boolean;
2861 -- If the allocator is an actual in a call, it is allowed to be
2862 -- class-wide when the context is not because it is a controlling
2863 -- actual.
2865 ----------------------------
2866 -- In_Dispatching_Context --
2867 ----------------------------
2869 function In_Dispatching_Context return Boolean is
2870 Par : constant Node_Id := Parent (N);
2872 begin
2873 return (Nkind (Par) = N_Function_Call
2874 or else Nkind (Par) = N_Procedure_Call_Statement)
2875 and then Is_Entity_Name (Name (Par))
2876 and then Is_Dispatching_Operation (Entity (Name (Par)));
2877 end In_Dispatching_Context;
2879 -- Start of processing for Resolve_Allocator
2881 begin
2882 -- Replace general access with specific type
2884 if Ekind (Etype (N)) = E_Allocator_Type then
2885 Set_Etype (N, Base_Type (Typ));
2886 end if;
2888 if Is_Abstract (Typ) then
2889 Error_Msg_N ("type of allocator cannot be abstract", N);
2890 end if;
2892 -- For qualified expression, resolve the expression using the
2893 -- given subtype (nothing to do for type mark, subtype indication)
2895 if Nkind (E) = N_Qualified_Expression then
2896 if Is_Class_Wide_Type (Etype (E))
2897 and then not Is_Class_Wide_Type (Designated_Type (Typ))
2898 and then not In_Dispatching_Context
2899 then
2900 Error_Msg_N
2901 ("class-wide allocator not allowed for this access type", N);
2902 end if;
2904 Resolve (Expression (E), Etype (E));
2905 Check_Unset_Reference (Expression (E));
2907 -- A qualified expression requires an exact match of the type,
2908 -- class-wide matching is not allowed.
2910 if (Is_Class_Wide_Type (Etype (Expression (E)))
2911 or else Is_Class_Wide_Type (Etype (E)))
2912 and then Base_Type (Etype (Expression (E))) /= Base_Type (Etype (E))
2913 then
2914 Wrong_Type (Expression (E), Etype (E));
2915 end if;
2917 -- For a subtype mark or subtype indication, freeze the subtype
2919 else
2920 Freeze_Expression (E);
2922 if Is_Access_Constant (Typ) and then not No_Initialization (N) then
2923 Error_Msg_N
2924 ("initialization required for access-to-constant allocator", N);
2925 end if;
2927 -- A special accessibility check is needed for allocators that
2928 -- constrain access discriminants. The level of the type of the
2929 -- expression used to contrain an access discriminant cannot be
2930 -- deeper than the type of the allocator (in constrast to access
2931 -- parameters, where the level of the actual can be arbitrary).
2932 -- We can't use Valid_Conversion to perform this check because
2933 -- in general the type of the allocator is unrelated to the type
2934 -- of the access discriminant. Note that specialized checks are
2935 -- needed for the cases of a constraint expression which is an
2936 -- access attribute or an access discriminant.
2938 if Nkind (Original_Node (E)) = N_Subtype_Indication
2939 and then Ekind (Typ) /= E_Anonymous_Access_Type
2940 then
2941 Subtyp := Entity (Subtype_Mark (Original_Node (E)));
2943 if Has_Discriminants (Subtyp) then
2944 Discrim := First_Discriminant (Base_Type (Subtyp));
2945 Constr := First (Constraints (Constraint (Original_Node (E))));
2947 while Present (Discrim) and then Present (Constr) loop
2948 if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
2949 if Nkind (Constr) = N_Discriminant_Association then
2950 Disc_Exp := Original_Node (Expression (Constr));
2951 else
2952 Disc_Exp := Original_Node (Constr);
2953 end if;
2955 if Type_Access_Level (Etype (Disc_Exp))
2956 > Type_Access_Level (Typ)
2957 then
2958 Error_Msg_N
2959 ("operand type has deeper level than allocator type",
2960 Disc_Exp);
2962 elsif Nkind (Disc_Exp) = N_Attribute_Reference
2963 and then Get_Attribute_Id (Attribute_Name (Disc_Exp))
2964 = Attribute_Access
2965 and then Object_Access_Level (Prefix (Disc_Exp))
2966 > Type_Access_Level (Typ)
2967 then
2968 Error_Msg_N
2969 ("prefix of attribute has deeper level than"
2970 & " allocator type", Disc_Exp);
2972 -- When the operand is an access discriminant the check
2973 -- is against the level of the prefix object.
2975 elsif Ekind (Etype (Disc_Exp)) = E_Anonymous_Access_Type
2976 and then Nkind (Disc_Exp) = N_Selected_Component
2977 and then Object_Access_Level (Prefix (Disc_Exp))
2978 > Type_Access_Level (Typ)
2979 then
2980 Error_Msg_N
2981 ("access discriminant has deeper level than"
2982 & " allocator type", Disc_Exp);
2983 end if;
2984 end if;
2985 Next_Discriminant (Discrim);
2986 Next (Constr);
2987 end loop;
2988 end if;
2989 end if;
2990 end if;
2992 -- Check for allocation from an empty storage pool
2994 if No_Pool_Assigned (Typ) then
2995 declare
2996 Loc : constant Source_Ptr := Sloc (N);
2998 begin
2999 Error_Msg_N ("?allocation from empty storage pool!", N);
3000 Error_Msg_N ("?Storage_Error will be raised at run time!", N);
3001 Insert_Action (N,
3002 Make_Raise_Storage_Error (Loc,
3003 Reason => SE_Empty_Storage_Pool));
3004 end;
3005 end if;
3006 end Resolve_Allocator;
3008 ---------------------------
3009 -- Resolve_Arithmetic_Op --
3010 ---------------------------
3012 -- Used for resolving all arithmetic operators except exponentiation
3014 procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id) is
3015 L : constant Node_Id := Left_Opnd (N);
3016 R : constant Node_Id := Right_Opnd (N);
3017 TL : constant Entity_Id := Base_Type (Etype (L));
3018 TR : constant Entity_Id := Base_Type (Etype (R));
3019 T : Entity_Id;
3020 Rop : Node_Id;
3022 B_Typ : constant Entity_Id := Base_Type (Typ);
3023 -- We do the resolution using the base type, because intermediate values
3024 -- in expressions always are of the base type, not a subtype of it.
3026 function Is_Integer_Or_Universal (N : Node_Id) return Boolean;
3027 -- Return True iff given type is Integer or universal real/integer
3029 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id);
3030 -- Choose type of integer literal in fixed-point operation to conform
3031 -- to available fixed-point type. T is the type of the other operand,
3032 -- which is needed to determine the expected type of N.
3034 procedure Set_Operand_Type (N : Node_Id);
3035 -- Set operand type to T if universal
3037 -----------------------------
3038 -- Is_Integer_Or_Universal --
3039 -----------------------------
3041 function Is_Integer_Or_Universal (N : Node_Id) return Boolean is
3042 T : Entity_Id;
3043 Index : Interp_Index;
3044 It : Interp;
3046 begin
3047 if not Is_Overloaded (N) then
3048 T := Etype (N);
3049 return Base_Type (T) = Base_Type (Standard_Integer)
3050 or else T = Universal_Integer
3051 or else T = Universal_Real;
3052 else
3053 Get_First_Interp (N, Index, It);
3055 while Present (It.Typ) loop
3057 if Base_Type (It.Typ) = Base_Type (Standard_Integer)
3058 or else It.Typ = Universal_Integer
3059 or else It.Typ = Universal_Real
3060 then
3061 return True;
3062 end if;
3064 Get_Next_Interp (Index, It);
3065 end loop;
3066 end if;
3068 return False;
3069 end Is_Integer_Or_Universal;
3071 ----------------------------
3072 -- Set_Mixed_Mode_Operand --
3073 ----------------------------
3075 procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id) is
3076 Index : Interp_Index;
3077 It : Interp;
3079 begin
3080 if Universal_Interpretation (N) = Universal_Integer then
3082 -- A universal integer literal is resolved as standard integer
3083 -- except in the case of a fixed-point result, where we leave
3084 -- it as universal (to be handled by Exp_Fixd later on)
3086 if Is_Fixed_Point_Type (T) then
3087 Resolve (N, Universal_Integer);
3088 else
3089 Resolve (N, Standard_Integer);
3090 end if;
3092 elsif Universal_Interpretation (N) = Universal_Real
3093 and then (T = Base_Type (Standard_Integer)
3094 or else T = Universal_Integer
3095 or else T = Universal_Real)
3096 then
3097 -- A universal real can appear in a fixed-type context. We resolve
3098 -- the literal with that context, even though this might raise an
3099 -- exception prematurely (the other operand may be zero).
3101 Resolve (N, B_Typ);
3103 elsif Etype (N) = Base_Type (Standard_Integer)
3104 and then T = Universal_Real
3105 and then Is_Overloaded (N)
3106 then
3107 -- Integer arg in mixed-mode operation. Resolve with universal
3108 -- type, in case preference rule must be applied.
3110 Resolve (N, Universal_Integer);
3112 elsif Etype (N) = T
3113 and then B_Typ /= Universal_Fixed
3114 then
3115 -- Not a mixed-mode operation. Resolve with context.
3117 Resolve (N, B_Typ);
3119 elsif Etype (N) = Any_Fixed then
3121 -- N may itself be a mixed-mode operation, so use context type.
3123 Resolve (N, B_Typ);
3125 elsif Is_Fixed_Point_Type (T)
3126 and then B_Typ = Universal_Fixed
3127 and then Is_Overloaded (N)
3128 then
3129 -- Must be (fixed * fixed) operation, operand must have one
3130 -- compatible interpretation.
3132 Resolve (N, Any_Fixed);
3134 elsif Is_Fixed_Point_Type (B_Typ)
3135 and then (T = Universal_Real
3136 or else Is_Fixed_Point_Type (T))
3137 and then Is_Overloaded (N)
3138 then
3139 -- C * F(X) in a fixed context, where C is a real literal or a
3140 -- fixed-point expression. F must have either a fixed type
3141 -- interpretation or an integer interpretation, but not both.
3143 Get_First_Interp (N, Index, It);
3145 while Present (It.Typ) loop
3146 if Base_Type (It.Typ) = Base_Type (Standard_Integer) then
3148 if Analyzed (N) then
3149 Error_Msg_N ("ambiguous operand in fixed operation", N);
3150 else
3151 Resolve (N, Standard_Integer);
3152 end if;
3154 elsif Is_Fixed_Point_Type (It.Typ) then
3156 if Analyzed (N) then
3157 Error_Msg_N ("ambiguous operand in fixed operation", N);
3158 else
3159 Resolve (N, It.Typ);
3160 end if;
3161 end if;
3163 Get_Next_Interp (Index, It);
3164 end loop;
3166 -- Reanalyze the literal with the fixed type of the context.
3168 if N = L then
3169 Set_Analyzed (R, False);
3170 Resolve (R, B_Typ);
3171 else
3172 Set_Analyzed (L, False);
3173 Resolve (L, B_Typ);
3174 end if;
3176 else
3177 Resolve (N);
3178 end if;
3179 end Set_Mixed_Mode_Operand;
3181 ----------------------
3182 -- Set_Operand_Type --
3183 ----------------------
3185 procedure Set_Operand_Type (N : Node_Id) is
3186 begin
3187 if Etype (N) = Universal_Integer
3188 or else Etype (N) = Universal_Real
3189 then
3190 Set_Etype (N, T);
3191 end if;
3192 end Set_Operand_Type;
3194 -- Start of processing for Resolve_Arithmetic_Op
3196 begin
3197 if Comes_From_Source (N)
3198 and then Ekind (Entity (N)) = E_Function
3199 and then Is_Imported (Entity (N))
3200 and then Is_Intrinsic_Subprogram (Entity (N))
3201 then
3202 Resolve_Intrinsic_Operator (N, Typ);
3203 return;
3205 -- Special-case for mixed-mode universal expressions or fixed point
3206 -- type operation: each argument is resolved separately. The same
3207 -- treatment is required if one of the operands of a fixed point
3208 -- operation is universal real, since in this case we don't do a
3209 -- conversion to a specific fixed-point type (instead the expander
3210 -- takes care of the case).
3212 elsif (B_Typ = Universal_Integer
3213 or else B_Typ = Universal_Real)
3214 and then Present (Universal_Interpretation (L))
3215 and then Present (Universal_Interpretation (R))
3216 then
3217 Resolve (L, Universal_Interpretation (L));
3218 Resolve (R, Universal_Interpretation (R));
3219 Set_Etype (N, B_Typ);
3221 elsif (B_Typ = Universal_Real
3222 or else Etype (N) = Universal_Fixed
3223 or else (Etype (N) = Any_Fixed
3224 and then Is_Fixed_Point_Type (B_Typ))
3225 or else (Is_Fixed_Point_Type (B_Typ)
3226 and then (Is_Integer_Or_Universal (L)
3227 or else
3228 Is_Integer_Or_Universal (R))))
3229 and then (Nkind (N) = N_Op_Multiply or else
3230 Nkind (N) = N_Op_Divide)
3231 then
3232 if TL = Universal_Integer or else TR = Universal_Integer then
3233 Check_For_Visible_Operator (N, B_Typ);
3234 end if;
3236 -- If context is a fixed type and one operand is integer, the
3237 -- other is resolved with the type of the context.
3239 if Is_Fixed_Point_Type (B_Typ)
3240 and then (Base_Type (TL) = Base_Type (Standard_Integer)
3241 or else TL = Universal_Integer)
3242 then
3243 Resolve (R, B_Typ);
3244 Resolve (L, TL);
3246 elsif Is_Fixed_Point_Type (B_Typ)
3247 and then (Base_Type (TR) = Base_Type (Standard_Integer)
3248 or else TR = Universal_Integer)
3249 then
3250 Resolve (L, B_Typ);
3251 Resolve (R, TR);
3253 else
3254 Set_Mixed_Mode_Operand (L, TR);
3255 Set_Mixed_Mode_Operand (R, TL);
3256 end if;
3258 if Etype (N) = Universal_Fixed
3259 or else Etype (N) = Any_Fixed
3260 then
3261 if B_Typ = Universal_Fixed
3262 and then Nkind (Parent (N)) /= N_Type_Conversion
3263 and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
3264 then
3265 Error_Msg_N
3266 ("type cannot be determined from context!", N);
3267 Error_Msg_N
3270 Set_Etype (L, Any_Type);
3271 Set_Etype (R, Any_Type);
3273 else
3274 if Ada_83
3275 and then Etype (N) = Universal_Fixed
3276 and then Nkind (Parent (N)) /= N_Type_Conversion
3277 and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
3278 then
3279 Error_Msg_N
3280 ("(Ada 83) fixed-point operation " &
3281 "needs explicit conversion",
3282 N);
3283 end if;
3285 Set_Etype (N, B_Typ);
3286 end if;
3288 elsif Is_Fixed_Point_Type (B_Typ)
3289 and then (Is_Integer_Or_Universal (L)
3290 or else Nkind (L) = N_Real_Literal
3291 or else Nkind (R) = N_Real_Literal
3292 or else
3293 Is_Integer_Or_Universal (R))
3294 then
3295 Set_Etype (N, B_Typ);
3297 elsif Etype (N) = Any_Fixed then
3299 -- If no previous errors, this is only possible if one operand
3300 -- is overloaded and the context is universal. Resolve as such.
3302 Set_Etype (N, B_Typ);
3303 end if;
3305 else
3306 if (TL = Universal_Integer or else TL = Universal_Real)
3307 and then (TR = Universal_Integer or else TR = Universal_Real)
3308 then
3309 Check_For_Visible_Operator (N, B_Typ);
3310 end if;
3312 -- If the context is Universal_Fixed and the operands are also
3313 -- universal fixed, this is an error, unless there is only one
3314 -- applicable fixed_point type (usually duration).
3316 if B_Typ = Universal_Fixed
3317 and then Etype (L) = Universal_Fixed
3318 then
3319 T := Unique_Fixed_Point_Type (N);
3321 if T = Any_Type then
3322 Set_Etype (N, T);
3323 return;
3324 else
3325 Resolve (L, T);
3326 Resolve (R, T);
3327 end if;
3329 else
3330 Resolve (L, B_Typ);
3331 Resolve (R, B_Typ);
3332 end if;
3334 -- If one of the arguments was resolved to a non-universal type.
3335 -- label the result of the operation itself with the same type.
3336 -- Do the same for the universal argument, if any.
3338 T := Intersect_Types (L, R);
3339 Set_Etype (N, Base_Type (T));
3340 Set_Operand_Type (L);
3341 Set_Operand_Type (R);
3342 end if;
3344 Generate_Operator_Reference (N, Typ);
3345 Eval_Arithmetic_Op (N);
3347 -- Set overflow and division checking bit. Much cleverer code needed
3348 -- here eventually and perhaps the Resolve routines should be separated
3349 -- for the various arithmetic operations, since they will need
3350 -- different processing. ???
3352 if Nkind (N) in N_Op then
3353 if not Overflow_Checks_Suppressed (Etype (N)) then
3354 Enable_Overflow_Check (N);
3355 end if;
3357 -- Give warning if explicit division by zero
3359 if (Nkind (N) = N_Op_Divide
3360 or else Nkind (N) = N_Op_Rem
3361 or else Nkind (N) = N_Op_Mod)
3362 and then not Division_Checks_Suppressed (Etype (N))
3363 then
3364 Rop := Right_Opnd (N);
3366 if Compile_Time_Known_Value (Rop)
3367 and then ((Is_Integer_Type (Etype (Rop))
3368 and then Expr_Value (Rop) = Uint_0)
3369 or else
3370 (Is_Real_Type (Etype (Rop))
3371 and then Expr_Value_R (Rop) = Ureal_0))
3372 then
3373 Apply_Compile_Time_Constraint_Error
3374 (N, "division by zero?", CE_Divide_By_Zero,
3375 Loc => Sloc (Right_Opnd (N)));
3377 -- Otherwise just set the flag to check at run time
3379 else
3380 Set_Do_Division_Check (N);
3381 end if;
3382 end if;
3383 end if;
3385 Check_Unset_Reference (L);
3386 Check_Unset_Reference (R);
3387 end Resolve_Arithmetic_Op;
3389 ------------------
3390 -- Resolve_Call --
3391 ------------------
3393 procedure Resolve_Call (N : Node_Id; Typ : Entity_Id) is
3394 Loc : constant Source_Ptr := Sloc (N);
3395 Subp : constant Node_Id := Name (N);
3396 Nam : Entity_Id;
3397 I : Interp_Index;
3398 It : Interp;
3399 Norm_OK : Boolean;
3400 Scop : Entity_Id;
3401 Decl : Node_Id;
3403 begin
3404 -- The context imposes a unique interpretation with type Typ on
3405 -- a procedure or function call. Find the entity of the subprogram
3406 -- that yields the expected type, and propagate the corresponding
3407 -- formal constraints on the actuals. The caller has established
3408 -- that an interpretation exists, and emitted an error if not unique.
3410 -- First deal with the case of a call to an access-to-subprogram,
3411 -- dereference made explicit in Analyze_Call.
3413 if Ekind (Etype (Subp)) = E_Subprogram_Type then
3414 if not Is_Overloaded (Subp) then
3415 Nam := Etype (Subp);
3417 else
3418 -- Find the interpretation whose type (a subprogram type)
3419 -- has a return type that is compatible with the context.
3420 -- Analysis of the node has established that one exists.
3422 Get_First_Interp (Subp, I, It);
3423 Nam := Empty;
3425 while Present (It.Typ) loop
3426 if Covers (Typ, Etype (It.Typ)) then
3427 Nam := It.Typ;
3428 exit;
3429 end if;
3431 Get_Next_Interp (I, It);
3432 end loop;
3434 if No (Nam) then
3435 raise Program_Error;
3436 end if;
3437 end if;
3439 -- If the prefix is not an entity, then resolve it
3441 if not Is_Entity_Name (Subp) then
3442 Resolve (Subp, Nam);
3443 end if;
3445 -- For an indirect call, we always invalidate checks, since we
3446 -- do not know whether the subprogram is local or global. Yes
3447 -- we could do better here, e.g. by knowing that there are no
3448 -- local subprograms, but it does not seem worth the effort.
3449 -- Similarly, we kill al knowledge of current constant values.
3451 Kill_Current_Values;
3453 -- If this is a procedure call which is really an entry call, do
3454 -- the conversion of the procedure call to an entry call. Protected
3455 -- operations use the same circuitry because the name in the call
3456 -- can be an arbitrary expression with special resolution rules.
3458 elsif Nkind (Subp) = N_Selected_Component
3459 or else Nkind (Subp) = N_Indexed_Component
3460 or else (Is_Entity_Name (Subp)
3461 and then Ekind (Entity (Subp)) = E_Entry)
3462 then
3463 Resolve_Entry_Call (N, Typ);
3464 Check_Elab_Call (N);
3466 -- Kill checks and constant values, as above for indirect case
3467 -- Who knows what happens when another task is activated?
3469 Kill_Current_Values;
3470 return;
3472 -- Normal subprogram call with name established in Resolve
3474 elsif not (Is_Type (Entity (Subp))) then
3475 Nam := Entity (Subp);
3476 Set_Entity_With_Style_Check (Subp, Nam);
3477 Generate_Reference (Nam, Subp);
3479 -- Otherwise we must have the case of an overloaded call
3481 else
3482 pragma Assert (Is_Overloaded (Subp));
3483 Nam := Empty; -- We know that it will be assigned in loop below.
3485 Get_First_Interp (Subp, I, It);
3487 while Present (It.Typ) loop
3488 if Covers (Typ, It.Typ) then
3489 Nam := It.Nam;
3490 Set_Entity_With_Style_Check (Subp, Nam);
3491 Generate_Reference (Nam, Subp);
3492 exit;
3493 end if;
3495 Get_Next_Interp (I, It);
3496 end loop;
3497 end if;
3499 -- Check that a call to Current_Task does not occur in an entry body
3501 if Is_RTE (Nam, RE_Current_Task) then
3502 declare
3503 P : Node_Id;
3505 begin
3506 P := N;
3507 loop
3508 P := Parent (P);
3509 exit when No (P);
3511 if Nkind (P) = N_Entry_Body then
3512 Error_Msg_NE
3514 N, Nam);
3515 exit;
3516 end if;
3517 end loop;
3518 end;
3519 end if;
3521 -- Cannot call thread body directly
3523 if Is_Thread_Body (Nam) then
3525 end if;
3527 -- If the subprogram is not global, then kill all checks. This is
3528 -- a bit conservative, since in many cases we could do better, but
3529 -- it is not worth the effort. Similarly, we kill constant values.
3530 -- However we do not need to do this for internal entities (unless
3531 -- they are inherited user-defined subprograms), since they are not
3532 -- in the business of molesting global values.
3534 if not Is_Library_Level_Entity (Nam)
3535 and then (Comes_From_Source (Nam)
3536 or else (Present (Alias (Nam))
3537 and then Comes_From_Source (Alias (Nam))))
3538 then
3539 Kill_Current_Values;
3540 end if;
3542 -- Check for call to obsolescent subprogram
3544 if Warn_On_Obsolescent_Feature then
3545 Decl := Parent (Parent (Nam));
3547 if Nkind (Decl) = N_Subprogram_Declaration
3548 and then Is_List_Member (Decl)
3549 and then Nkind (Next (Decl)) = N_Pragma
3550 then
3551 declare
3552 P : constant Node_Id := Next (Decl);
3554 begin
3555 if Chars (P) = Name_Obsolescent then
3558 if Pragma_Argument_Associations (P) /= No_List then
3559 Name_Buffer (1) := '|';
3560 Name_Buffer (2) := '?';
3561 Name_Len := 2;
3562 Add_String_To_Name_Buffer
3563 (Strval (Expression
3564 (First (Pragma_Argument_Associations (P)))));
3565 Error_Msg_N (Name_Buffer (1 .. Name_Len), N);
3566 end if;
3567 end if;
3568 end;
3569 end if;
3570 end if;
3572 -- Check that a procedure call does not occur in the context
3573 -- of the entry call statement of a conditional or timed
3574 -- entry call. Note that the case of a call to a subprogram
3575 -- renaming of an entry will also be rejected. The test
3576 -- for N not being an N_Entry_Call_Statement is defensive,
3577 -- covering the possibility that the processing of entry
3578 -- calls might reach this point due to later modifications
3579 -- of the code above.
3581 if Nkind (Parent (N)) = N_Entry_Call_Alternative
3582 and then Nkind (N) /= N_Entry_Call_Statement
3583 and then Entry_Call_Statement (Parent (N)) = N
3584 then
3586 end if;
3588 -- Check that this is not a call to a protected procedure or
3589 -- entry from within a protected function.
3591 if Ekind (Current_Scope) = E_Function
3592 and then Ekind (Scope (Current_Scope)) = E_Protected_Type
3593 and then Ekind (Nam) /= E_Function
3594 and then Scope (Nam) = Scope (Current_Scope)
3595 then
3599 end if;
3601 -- Freeze the subprogram name if not in default expression. Note
3602 -- that we freeze procedure calls as well as function calls.
3603 -- Procedure calls are not frozen according to the rules (RM
3604 -- 13.14(14)) because it is impossible to have a procedure call to
3605 -- a non-frozen procedure in pure Ada, but in the code that we
3606 -- generate in the expander, this rule needs extending because we
3607 -- can generate procedure calls that need freezing.
3609 if Is_Entity_Name (Subp) and then not In_Default_Expression then
3610 Freeze_Expression (Subp);
3611 end if;
3613 -- For a predefined operator, the type of the result is the type
3614 -- imposed by context, except for a predefined operation on universal
3615 -- fixed. Otherwise The type of the call is the type returned by the
3616 -- subprogram being called.
3618 if Is_Predefined_Op (Nam) then
3619 if Etype (N) /= Universal_Fixed then
3620 Set_Etype (N, Typ);
3621 end if;
3623 -- If the subprogram returns an array type, and the context
3624 -- requires the component type of that array type, the node is
3625 -- really an indexing of the parameterless call. Resolve as such.
3626 -- A pathological case occurs when the type of the component is
3627 -- an access to the array type. In this case the call is truly
3628 -- ambiguous.
3630 elsif Needs_No_Actuals (Nam)
3631 and then
3632 ((Is_Array_Type (Etype (Nam))
3633 and then Covers (Typ, Component_Type (Etype (Nam))))
3634 or else (Is_Access_Type (Etype (Nam))
3635 and then Is_Array_Type (Designated_Type (Etype (Nam)))
3636 and then
3637 Covers (Typ,
3638 Component_Type (Designated_Type (Etype (Nam))))))
3639 then
3640 declare
3641 Index_Node : Node_Id;
3642 New_Subp : Node_Id;
3643 Ret_Type : constant Entity_Id := Etype (Nam);
3645 begin
3646 if Is_Access_Type (Ret_Type)
3647 and then Ret_Type = Component_Type (Designated_Type (Ret_Type))
3648 then
3649 Error_Msg_N
3651 else
3652 New_Subp := Relocate_Node (Subp);
3653 Set_Entity (Subp, Nam);
3655 if Component_Type (Ret_Type) /= Any_Type then
3656 Index_Node :=
3657 Make_Indexed_Component (Loc,
3658 Prefix =>
3659 Make_Function_Call (Loc,
3660 Name => New_Subp),
3661 Expressions => Parameter_Associations (N));
3663 -- Since we are correcting a node classification error made
3664 -- by the parser, we call Replace rather than Rewrite.
3666 Replace (N, Index_Node);
3667 Set_Etype (Prefix (N), Ret_Type);
3668 Set_Etype (N, Typ);
3669 Resolve_Indexed_Component (N, Typ);
3670 Check_Elab_Call (Prefix (N));
3671 end if;
3672 end if;
3674 return;
3675 end;
3677 else
3678 Set_Etype (N, Etype (Nam));
3679 end if;
3681 -- In the case where the call is to an overloaded subprogram, Analyze
3682 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
3683 -- such a case Normalize_Actuals needs to be called once more to order
3684 -- the actuals correctly. Otherwise the call will have the ordering
3685 -- given by the last overloaded subprogram whether this is the correct
3686 -- one being called or not.
3688 if Is_Overloaded (Subp) then
3689 Normalize_Actuals (N, Nam, False, Norm_OK);
3690 pragma Assert (Norm_OK);
3691 end if;
3693 -- In any case, call is fully resolved now. Reset Overload flag, to
3694 -- prevent subsequent overload resolution if node is analyzed again
3696 Set_Is_Overloaded (Subp, False);
3697 Set_Is_Overloaded (N, False);
3699 -- If we are calling the current subprogram from immediately within
3700 -- its body, then that is the case where we can sometimes detect
3701 -- cases of infinite recursion statically. Do not try this in case
3702 -- restriction No_Recursion is in effect anyway.
3704 Scop := Current_Scope;
3706 if Nam = Scop
3707 and then not Restriction_Active (No_Recursion)
3708 and then Check_Infinite_Recursion (N)
3709 then
3710 -- Here we detected and flagged an infinite recursion, so we do
3711 -- not need to test the case below for further warnings.
3713 null;
3715 -- If call is to immediately containing subprogram, then check for
3716 -- the case of a possible run-time detectable infinite recursion.
3718 else
3719 while Scop /= Standard_Standard loop
3720 if Nam = Scop then
3721 -- Although in general recursion is not statically checkable,
3722 -- the case of calling an immediately containing subprogram
3723 -- is easy to catch.
3725 Check_Restriction (No_Recursion, N);
3727 -- If the recursive call is to a parameterless procedure, then
3728 -- even if we can't statically detect infinite recursion, this
3729 -- is pretty suspicious, and we output a warning. Furthermore,
3730 -- we will try later to detect some cases here at run time by
3731 -- expanding checking code (see Detect_Infinite_Recursion in
3732 -- package Exp_Ch6).
3733 -- If the recursive call is within a handler we do not emit a
3734 -- warning, because this is a common idiom: loop until input
3735 -- is correct, catch illegal input in handler and restart.
3737 if No (First_Formal (Nam))
3738 and then Etype (Nam) = Standard_Void_Type
3739 and then not Error_Posted (N)
3740 and then Nkind (Parent (N)) /= N_Exception_Handler
3741 then
3742 Set_Has_Recursive_Call (Nam);
3745 end if;
3747 exit;
3748 end if;
3750 Scop := Scope (Scop);
3751 end loop;
3752 end if;
3754 -- If subprogram name is a predefined operator, it was given in
3755 -- functional notation. Replace call node with operator node, so
3756 -- that actuals can be resolved appropriately.
3758 if Is_Predefined_Op (Nam) or else Ekind (Nam) = E_Operator then
3759 Make_Call_Into_Operator (N, Typ, Entity (Name (N)));
3760 return;
3762 elsif Present (Alias (Nam))
3763 and then Is_Predefined_Op (Alias (Nam))
3764 then
3765 Resolve_Actuals (N, Nam);
3766 Make_Call_Into_Operator (N, Typ, Alias (Nam));
3767 return;
3768 end if;
3770 -- Create a transient scope if the resulting type requires it
3772 -- There are 3 notable exceptions: in init procs, the transient scope
3773 -- overhead is not needed and even incorrect due to the actual expansion
3774 -- of adjust calls; the second case is enumeration literal pseudo calls,
3775 -- the other case is intrinsic subprograms (Unchecked_Conversion and
3776 -- source information functions) that do not use the secondary stack
3777 -- even though the return type is unconstrained.
3779 -- If this is an initialization call for a type whose initialization
3780 -- uses the secondary stack, we also need to create a transient scope
3781 -- for it, precisely because we will not do it within the init proc
3782 -- itself.
3784 if Expander_Active
3785 and then Is_Type (Etype (Nam))
3786 and then Requires_Transient_Scope (Etype (Nam))
3787 and then Ekind (Nam) /= E_Enumeration_Literal
3788 and then not Within_Init_Proc
3789 and then not Is_Intrinsic_Subprogram (Nam)
3790 then
3791 Establish_Transient_Scope
3792 (N, Sec_Stack => not Functions_Return_By_DSP_On_Target);
3794 -- If the call appears within the bounds of a loop, it will
3795 -- be rewritten and reanalyzed, nothing left to do here.
3797 if Nkind (N) /= N_Function_Call then
3798 return;
3799 end if;
3801 elsif Is_Init_Proc (Nam)
3802 and then not Within_Init_Proc
3803 then
3804 Check_Initialization_Call (N, Nam);
3805 end if;
3807 -- A protected function cannot be called within the definition of the
3808 -- enclosing protected type.
3810 if Is_Protected_Type (Scope (Nam))
3811 and then In_Open_Scopes (Scope (Nam))
3812 and then not Has_Completion (Scope (Nam))
3813 then
3814 Error_Msg_NE
3816 end if;
3818 -- Propagate interpretation to actuals, and add default expressions
3819 -- where needed.
3821 if Present (First_Formal (Nam)) then
3822 Resolve_Actuals (N, Nam);
3824 -- Overloaded literals are rewritten as function calls, for
3825 -- purpose of resolution. After resolution, we can replace
3826 -- the call with the literal itself.
3828 elsif Ekind (Nam) = E_Enumeration_Literal then
3829 Copy_Node (Subp, N);
3830 Resolve_Entity_Name (N, Typ);
3832 -- Avoid validation, since it is a static function call
3834 return;
3835 end if;
3837 -- If the subprogram is a primitive operation, check whether or not
3838 -- it is a correct dispatching call.
3840 if Is_Overloadable (Nam)
3841 and then Is_Dispatching_Operation (Nam)
3842 then
3843 Check_Dispatching_Call (N);
3845 elsif Is_Abstract (Nam)
3846 and then not In_Instance
3847 then
3849 end if;
3851 if Is_Intrinsic_Subprogram (Nam) then
3852 Check_Intrinsic_Call (N);
3853 end if;
3855 Eval_Call (N);
3856 Check_Elab_Call (N);
3857 end Resolve_Call;
3859 -------------------------------
3860 -- Resolve_Character_Literal --
3861 -------------------------------
3863 procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id) is
3864 B_Typ : constant Entity_Id := Base_Type (Typ);
3865 C : Entity_Id;
3867 begin
3868 -- Verify that the character does belong to the type of the context
3870 Set_Etype (N, B_Typ);
3871 Eval_Character_Literal (N);
3873 -- Wide_Character literals must always be defined, since the set of
3874 -- wide character literals is complete, i.e. if a character literal
3875 -- is accepted by the parser, then it is OK for wide character.
3877 if Root_Type (B_Typ) = Standard_Wide_Character then
3878 return;
3880 -- Always accept character literal for type Any_Character, which
3881 -- occurs in error situations and in comparisons of literals, both
3882 -- of which should accept all literals.
3884 elsif B_Typ = Any_Character then
3885 return;
3887 -- For Standard.Character or a type derived from it, check that
3888 -- the literal is in range
3890 elsif Root_Type (B_Typ) = Standard_Character then
3891 if In_Character_Range (Char_Literal_Value (N)) then
3892 return;
3893 end if;
3895 -- If the entity is already set, this has already been resolved in
3896 -- a generic context, or comes from expansion. Nothing else to do.
3898 elsif Present (Entity (N)) then
3899 return;
3901 -- Otherwise we have a user defined character type, and we can use
3902 -- the standard visibility mechanisms to locate the referenced entity
3904 else
3905 C := Current_Entity (N);
3907 while Present (C) loop
3908 if Etype (C) = B_Typ then
3909 Set_Entity_With_Style_Check (N, C);
3910 Generate_Reference (C, N);
3911 return;
3912 end if;
3914 C := Homonym (C);
3915 end loop;
3916 end if;
3918 -- If we fall through, then the literal does not match any of the
3919 -- entries of the enumeration type. This isn't just a constraint
3920 -- error situation, it is an illegality (see RM 4.2).
3922 Error_Msg_NE
3924 end Resolve_Character_Literal;
3926 ---------------------------
3927 -- Resolve_Comparison_Op --
3928 ---------------------------
3930 -- Context requires a boolean type, and plays no role in resolution.
3931 -- Processing identical to that for equality operators. The result
3932 -- type is the base type, which matters when pathological subtypes of
3933 -- booleans with limited ranges are used.
3935 procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id) is
3936 L : constant Node_Id := Left_Opnd (N);
3937 R : constant Node_Id := Right_Opnd (N);
3938 T : Entity_Id;
3940 begin
3941 Check_Direct_Boolean_Op (N);
3943 -- If this is an intrinsic operation which is not predefined, use
3944 -- the types of its declared arguments to resolve the possibly
3945 -- overloaded operands. Otherwise the operands are unambiguous and
3946 -- specify the expected type.
3948 if Scope (Entity (N)) /= Standard_Standard then
3949 T := Etype (First_Entity (Entity (N)));
3950 else
3951 T := Find_Unique_Type (L, R);
3953 if T = Any_Fixed then
3954 T := Unique_Fixed_Point_Type (L);
3955 end if;
3956 end if;
3958 Set_Etype (N, Base_Type (Typ));
3959 Generate_Reference (T, N, ' ');
3961 if T /= Any_Type then
3962 if T = Any_String
3963 or else T = Any_Composite
3964 or else T = Any_Character
3965 then
3966 if T = Any_Character then
3967 Ambiguous_Character (L);
3968 else
3970 end if;
3972 Set_Etype (N, Any_Type);
3973 return;
3975 else
3976 if Comes_From_Source (N)
3977 and then Has_Unchecked_Union (T)
3978 then
3979 Error_Msg_N
3981 end if;
3983 Resolve (L, T);
3984 Resolve (R, T);
3985 Check_Unset_Reference (L);
3986 Check_Unset_Reference (R);
3987 Generate_Operator_Reference (N, T);
3988 Eval_Relational_Op (N);
3989 end if;
3990 end if;
3991 end Resolve_Comparison_Op;
3993 ------------------------------------
3994 -- Resolve_Conditional_Expression --
3995 ------------------------------------
3997 procedure Resolve_Conditional_Expression (N : Node_Id; Typ : Entity_Id) is
3998 Condition : constant Node_Id := First (Expressions (N));
3999 Then_Expr : constant Node_Id := Next (Condition);
4000 Else_Expr : constant Node_Id := Next (Then_Expr);
4002 begin
4003 Resolve (Condition, Standard_Boolean);
4004 Resolve (Then_Expr, Typ);
4005 Resolve (Else_Expr, Typ);
4007 Set_Etype (N, Typ);
4008 Eval_Conditional_Expression (N);
4009 end Resolve_Conditional_Expression;
4011 -----------------------------------------
4012 -- Resolve_Discrete_Subtype_Indication --
4013 -----------------------------------------
4015 procedure Resolve_Discrete_Subtype_Indication
4016 (N : Node_Id;
4017 Typ : Entity_Id)
4018 is
4019 R : Node_Id;
4020 S : Entity_Id;
4022 begin
4023 Analyze (Subtype_Mark (N));
4024 S := Entity (Subtype_Mark (N));
4026 if Nkind (Constraint (N)) /= N_Range_Constraint then
4028 Set_Etype (N, Any_Type);
4030 else
4031 R := Range_Expression (Constraint (N));
4033 if R = Error then
4034 return;
4035 end if;
4037 Analyze (R);
4039 if Base_Type (S) /= Base_Type (Typ) then
4040 Error_Msg_NE
4043 -- Rewrite the constraint as a range of Typ
4044 -- to allow compilation to proceed further.
4046 Set_Etype (N, Typ);
4047 Rewrite (Low_Bound (R),
4048 Make_Attribute_Reference (Sloc (Low_Bound (R)),
4049 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
4050 Attribute_Name => Name_First));
4051 Rewrite (High_Bound (R),
4052 Make_Attribute_Reference (Sloc (High_Bound (R)),
4053 Prefix => New_Occurrence_Of (Typ, Sloc (R)),
4054 Attribute_Name => Name_First));
4056 else
4057 Resolve (R, Typ);
4058 Set_Etype (N, Etype (R));
4060 -- Additionally, we must check that the bounds are compatible
4061 -- with the given subtype, which might be different from the
4062 -- type of the context.
4064 Apply_Range_Check (R, S);
4066 -- ??? If the above check statically detects a Constraint_Error
4067 -- it replaces the offending bound(s) of the range R with a
4068 -- Constraint_Error node. When the itype which uses these bounds
4069 -- is frozen the resulting call to Duplicate_Subexpr generates
4070 -- a new temporary for the bounds.
4072 -- Unfortunately there are other itypes that are also made depend
4073 -- on these bounds, so when Duplicate_Subexpr is called they get
4074 -- a forward reference to the newly created temporaries and Gigi
4075 -- aborts on such forward references. This is probably sign of a
4076 -- more fundamental problem somewhere else in either the order of
4077 -- itype freezing or the way certain itypes are constructed.
4079 -- To get around this problem we call Remove_Side_Effects right
4080 -- away if either bounds of R are a Constraint_Error.
4082 declare
4083 L : constant Node_Id := Low_Bound (R);
4084 H : constant Node_Id := High_Bound (R);
4086 begin
4087 if Nkind (L) = N_Raise_Constraint_Error then
4088 Remove_Side_Effects (L);
4089 end if;
4091 if Nkind (H) = N_Raise_Constraint_Error then
4092 Remove_Side_Effects (H);
4093 end if;
4094 end;
4096 Check_Unset_Reference (Low_Bound (R));
4097 Check_Unset_Reference (High_Bound (R));
4098 end if;
4099 end if;
4100 end Resolve_Discrete_Subtype_Indication;
4102 -------------------------
4103 -- Resolve_Entity_Name --
4104 -------------------------
4106 -- Used to resolve identifiers and expanded names
4108 procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id) is
4109 E : constant Entity_Id := Entity (N);
4111 begin
4112 -- If garbage from errors, set to Any_Type and return
4114 if No (E) and then Total_Errors_Detected /= 0 then
4115 Set_Etype (N, Any_Type);
4116 return;
4117 end if;
4119 -- Replace named numbers by corresponding literals. Note that this is
4120 -- the one case where Resolve_Entity_Name must reset the Etype, since
4121 -- it is currently marked as universal.
4123 if Ekind (E) = E_Named_Integer then
4124 Set_Etype (N, Typ);
4125 Eval_Named_Integer (N);
4127 elsif Ekind (E) = E_Named_Real then
4128 Set_Etype (N, Typ);
4129 Eval_Named_Real (N);
4131 -- Allow use of subtype only if it is a concurrent type where we are
4132 -- currently inside the body. This will eventually be expanded
4133 -- into a call to Self (for tasks) or _object (for protected
4134 -- objects). Any other use of a subtype is invalid.
4136 elsif Is_Type (E) then
4137 if Is_Concurrent_Type (E)
4138 and then In_Open_Scopes (E)
4139 then
4140 null;
4141 else
4142 Error_Msg_N
4144 end if;
4146 -- Check discriminant use if entity is discriminant in current scope,
4147 -- i.e. discriminant of record or concurrent type currently being
4148 -- analyzed. Uses in corresponding body are unrestricted.
4150 elsif Ekind (E) = E_Discriminant
4151 and then Scope (E) = Current_Scope
4152 and then not Has_Completion (Current_Scope)
4153 then
4154 Check_Discriminant_Use (N);
4156 -- A parameterless generic function cannot appear in a context that
4157 -- requires resolution.
4159 elsif Ekind (E) = E_Generic_Function then
4162 elsif Ekind (E) = E_Out_Parameter
4163 and then Ada_83
4164 and then (Nkind (Parent (N)) in N_Op
4165 or else (Nkind (Parent (N)) = N_Assignment_Statement
4166 and then N = Expression (Parent (N)))
4167 or else Nkind (Parent (N)) = N_Explicit_Dereference)
4168 then
4171 -- In all other cases, just do the possible static evaluation
4173 else
4174 -- A deferred constant that appears in an expression must have
4175 -- a completion, unless it has been removed by in-place expansion
4176 -- of an aggregate.
4178 if Ekind (E) = E_Constant
4179 and then Comes_From_Source (E)
4180 and then No (Constant_Value (E))
4181 and then Is_Frozen (Etype (E))
4182 and then not In_Default_Expression
4183 and then not Is_Imported (E)
4184 then
4186 if No_Initialization (Parent (E))
4187 or else (Present (Full_View (E))
4188 and then No_Initialization (Parent (Full_View (E))))
4189 then
4190 null;
4191 else
4192 Error_Msg_N (
4194 end if;
4195 end if;
4197 Eval_Entity_Name (N);
4198 end if;
4199 end Resolve_Entity_Name;
4201 -------------------
4202 -- Resolve_Entry --
4203 -------------------
4205 procedure Resolve_Entry (Entry_Name : Node_Id) is
4206 Loc : constant Source_Ptr := Sloc (Entry_Name);
4207 Nam : Entity_Id;
4208 New_N : Node_Id;
4209 S : Entity_Id;
4210 Tsk : Entity_Id;
4211 E_Name : Node_Id;
4212 Index : Node_Id;
4214 function Actual_Index_Type (E : Entity_Id) return Entity_Id;
4215 -- If the bounds of the entry family being called depend on task
4216 -- discriminants, build a new index subtype where a discriminant is
4217 -- replaced with the value of the discriminant of the target task.
4218 -- The target task is the prefix of the entry name in the call.
4220 -----------------------
4221 -- Actual_Index_Type --
4222 -----------------------
4224 function Actual_Index_Type (E : Entity_Id) return Entity_Id is
4225 Typ : constant Entity_Id := Entry_Index_Type (E);
4226 Tsk : constant Entity_Id := Scope (E);
4227 Lo : constant Node_Id := Type_Low_Bound (Typ);
4228 Hi : constant Node_Id := Type_High_Bound (Typ);
4229 New_T : Entity_Id;
4231 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id;
4232 -- If the bound is given by a discriminant, replace with a reference
4233 -- to the discriminant of the same name in the target task.
4234 -- If the entry name is the target of a requeue statement and the
4235 -- entry is in the current protected object, the bound to be used
4236 -- is the discriminal of the object (see apply_range_checks for
4237 -- details of the transformation).
4239 -----------------------------
4240 -- Actual_Discriminant_Ref --
4241 -----------------------------
4243 function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id is
4244 Typ : constant Entity_Id := Etype (Bound);
4245 Ref : Node_Id;
4247 begin
4248 Remove_Side_Effects (Bound);
4250 if not Is_Entity_Name (Bound)
4251 or else Ekind (Entity (Bound)) /= E_Discriminant
4252 then
4253 return Bound;
4255 elsif Is_Protected_Type (Tsk)
4256 and then In_Open_Scopes (Tsk)
4257 and then Nkind (Parent (Entry_Name)) = N_Requeue_Statement
4258 then
4259 return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc);
4261 else
4262 Ref :=
4263 Make_Selected_Component (Loc,
4264 Prefix => New_Copy_Tree (Prefix (Prefix (Entry_Name))),
4265 Selector_Name => New_Occurrence_Of (Entity (Bound), Loc));
4266 Analyze (Ref);
4267 Resolve (Ref, Typ);
4268 return Ref;
4269 end if;
4270 end Actual_Discriminant_Ref;
4272 -- Start of processing for Actual_Index_Type
4274 begin
4275 if not Has_Discriminants (Tsk)
4276 or else (not Is_Entity_Name (Lo)
4277 and then not Is_Entity_Name (Hi))
4278 then
4279 return Entry_Index_Type (E);
4281 else
4282 New_T := Create_Itype (Ekind (Typ), Parent (Entry_Name));
4283 Set_Etype (New_T, Base_Type (Typ));
4284 Set_Size_Info (New_T, Typ);
4285 Set_RM_Size (New_T, RM_Size (Typ));
4286 Set_Scalar_Range (New_T,
4287 Make_Range (Sloc (Entry_Name),
4288 Low_Bound => Actual_Discriminant_Ref (Lo),
4289 High_Bound => Actual_Discriminant_Ref (Hi)));
4291 return New_T;
4292 end if;
4293 end Actual_Index_Type;
4295 -- Start of processing of Resolve_Entry
4297 begin
4298 -- Find name of entry being called, and resolve prefix of name
4299 -- with its own type. The prefix can be overloaded, and the name
4300 -- and signature of the entry must be taken into account.
4302 if Nkind (Entry_Name) = N_Indexed_Component then
4304 -- Case of dealing with entry family within the current tasks
4306 E_Name := Prefix (Entry_Name);
4308 else
4309 E_Name := Entry_Name;
4310 end if;
4312 if Is_Entity_Name (E_Name) then
4313 -- Entry call to an entry (or entry family) in the current task.
4314 -- This is legal even though the task will deadlock. Rewrite as
4315 -- call to current task.
4317 -- This can also be a call to an entry in an enclosing task.
4318 -- If this is a single task, we have to retrieve its name,
4319 -- because the scope of the entry is the task type, not the
4320 -- object. If the enclosing task is a task type, the identity
4321 -- of the task is given by its own self variable.
4323 -- Finally this can be a requeue on an entry of the same task
4324 -- or protected object.
4326 S := Scope (Entity (E_Name));
4328 for J in reverse 0 .. Scope_Stack.Last loop
4330 if Is_Task_Type (Scope_Stack.Table (J).Entity)
4331 and then not Comes_From_Source (S)
4332 then
4333 -- S is an enclosing task or protected object. The concurrent
4334 -- declaration has been converted into a type declaration, and
4335 -- the object itself has an object declaration that follows
4336 -- the type in the same declarative part.
4338 Tsk := Next_Entity (S);
4340 while Etype (Tsk) /= S loop
4341 Next_Entity (Tsk);
4342 end loop;
4344 S := Tsk;
4345 exit;
4347 elsif S = Scope_Stack.Table (J).Entity then
4349 -- Call to current task. Will be transformed into call to Self
4351 exit;
4353 end if;
4354 end loop;
4356 New_N :=
4357 Make_Selected_Component (Loc,
4358 Prefix => New_Occurrence_Of (S, Loc),
4359 Selector_Name =>
4360 New_Occurrence_Of (Entity (E_Name), Loc));
4361 Rewrite (E_Name, New_N);
4362 Analyze (E_Name);
4364 elsif Nkind (Entry_Name) = N_Selected_Component
4365 and then Is_Overloaded (Prefix (Entry_Name))
4366 then
4367 -- Use the entry name (which must be unique at this point) to
4368 -- find the prefix that returns the corresponding task type or
4369 -- protected type.
4371 declare
4372 Pref : constant Node_Id := Prefix (Entry_Name);
4373 Ent : constant Entity_Id := Entity (Selector_Name (Entry_Name));
4374 I : Interp_Index;
4375 It : Interp;
4377 begin
4378 Get_First_Interp (Pref, I, It);
4380 while Present (It.Typ) loop
4382 if Scope (Ent) = It.Typ then
4383 Set_Etype (Pref, It.Typ);
4384 exit;
4385 end if;
4387 Get_Next_Interp (I, It);
4388 end loop;
4389 end;
4390 end if;
4392 if Nkind (Entry_Name) = N_Selected_Component then
4393 Resolve (Prefix (Entry_Name));
4395 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
4396 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
4397 Resolve (Prefix (Prefix (Entry_Name)));
4398 Index := First (Expressions (Entry_Name));
4399 Resolve (Index, Entry_Index_Type (Nam));
4401 -- Up to this point the expression could have been the actual
4402 -- in a simple entry call, and be given by a named association.
4404 if Nkind (Index) = N_Parameter_Association then
4406 else
4407 Apply_Range_Check (Index, Actual_Index_Type (Nam));
4408 end if;
4409 end if;
4410 end Resolve_Entry;
4412 ------------------------
4413 -- Resolve_Entry_Call --
4414 ------------------------
4416 procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id) is
4417 Entry_Name : constant Node_Id := Name (N);
4418 Loc : constant Source_Ptr := Sloc (Entry_Name);
4419 Actuals : List_Id;
4420 First_Named : Node_Id;
4421 Nam : Entity_Id;
4422 Norm_OK : Boolean;
4423 Obj : Node_Id;
4424 Was_Over : Boolean;
4426 begin
4427 -- We kill all checks here, because it does not seem worth the
4428 -- effort to do anything better, an entry call is a big operation.
4430 Kill_All_Checks;
4432 -- Processing of the name is similar for entry calls and protected
4433 -- operation calls. Once the entity is determined, we can complete
4434 -- the resolution of the actuals.
4436 -- The selector may be overloaded, in the case of a protected object
4437 -- with overloaded functions. The type of the context is used for
4438 -- resolution.
4440 if Nkind (Entry_Name) = N_Selected_Component
4441 and then Is_Overloaded (Selector_Name (Entry_Name))
4442 and then Typ /= Standard_Void_Type
4443 then
4444 declare
4445 I : Interp_Index;
4446 It : Interp;
4448 begin
4449 Get_First_Interp (Selector_Name (Entry_Name), I, It);
4451 while Present (It.Typ) loop
4453 if Covers (Typ, It.Typ) then
4454 Set_Entity (Selector_Name (Entry_Name), It.Nam);
4455 Set_Etype (Entry_Name, It.Typ);
4457 Generate_Reference (It.Typ, N, ' ');
4458 end if;
4460 Get_Next_Interp (I, It);
4461 end loop;
4462 end;
4463 end if;
4465 Resolve_Entry (Entry_Name);
4467 if Nkind (Entry_Name) = N_Selected_Component then
4469 -- Simple entry call.
4471 Nam := Entity (Selector_Name (Entry_Name));
4472 Obj := Prefix (Entry_Name);
4473 Was_Over := Is_Overloaded (Selector_Name (Entry_Name));
4475 else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
4477 -- Call to member of entry family.
4479 Nam := Entity (Selector_Name (Prefix (Entry_Name)));
4480 Obj := Prefix (Prefix (Entry_Name));
4481 Was_Over := Is_Overloaded (Selector_Name (Prefix (Entry_Name)));
4482 end if;
4484 -- We cannot in general check the maximum depth of protected entry
4485 -- calls at compile time. But we can tell that any protected entry
4486 -- call at all violates a specified nesting depth of zero.
4488 if Is_Protected_Type (Scope (Nam)) then
4489 Check_Restriction (Max_Entry_Queue_Depth, N);
4490 end if;
4492 -- Use context type to disambiguate a protected function that can be
4493 -- called without actuals and that returns an array type, and where
4494 -- the argument list may be an indexing of the returned value.
4496 if Ekind (Nam) = E_Function
4497 and then Needs_No_Actuals (Nam)
4498 and then Present (Parameter_Associations (N))
4499 and then
4500 ((Is_Array_Type (Etype (Nam))
4501 and then Covers (Typ, Component_Type (Etype (Nam))))
4503 or else (Is_Access_Type (Etype (Nam))
4504 and then Is_Array_Type (Designated_Type (Etype (Nam)))
4505 and then Covers (Typ,
4506 Component_Type (Designated_Type (Etype (Nam))))))
4507 then
4508 declare
4509 Index_Node : Node_Id;
4511 begin
4512 Index_Node :=
4513 Make_Indexed_Component (Loc,
4514 Prefix =>
4515 Make_Function_Call (Loc,
4516 Name => Relocate_Node (Entry_Name)),
4517 Expressions => Parameter_Associations (N));
4519 -- Since we are correcting a node classification error made by
4520 -- the parser, we call Replace rather than Rewrite.
4522 Replace (N, Index_Node);
4523 Set_Etype (Prefix (N), Etype (Nam));
4524 Set_Etype (N, Typ);
4525 Resolve_Indexed_Component (N, Typ);
4526 return;
4527 end;
4528 end if;
4530 -- The operation name may have been overloaded. Order the actuals
4531 -- according to the formals of the resolved entity, and set the
4532 -- return type to that of the operation.
4534 if Was_Over then
4535 Normalize_Actuals (N, Nam, False, Norm_OK);
4536 pragma Assert (Norm_OK);
4537 Set_Etype (N, Etype (Nam));
4538 end if;
4540 Resolve_Actuals (N, Nam);
4541 Generate_Reference (Nam, Entry_Name);
4543 if Ekind (Nam) = E_Entry
4544 or else Ekind (Nam) = E_Entry_Family
4545 then
4546 Check_Potentially_Blocking_Operation (N);
4547 end if;
4549 -- Verify that a procedure call cannot masquerade as an entry
4550 -- call where an entry call is expected.
4552 if Ekind (Nam) = E_Procedure then
4553 if Nkind (Parent (N)) = N_Entry_Call_Alternative
4554 and then N = Entry_Call_Statement (Parent (N))
4555 then
4558 elsif Nkind (Parent (N)) = N_Triggering_Alternative
4559 and then N = Triggering_Statement (Parent (N))
4560 then
4563 elsif Ekind (Scope (Nam)) = E_Task_Type
4564 and then not In_Open_Scopes (Scope (Nam))
4565 then
4567 end if;
4568 end if;
4570 -- After resolution, entry calls and protected procedure calls
4571 -- are changed into entry calls, for expansion. The structure
4572 -- of the node does not change, so it can safely be done in place.
4573 -- Protected function calls must keep their structure because they
4574 -- are subexpressions.
4576 if Ekind (Nam) /= E_Function then
4578 -- A protected operation that is not a function may modify the
4579 -- corresponding object, and cannot apply to a constant.
4580 -- If this is an internal call, the prefix is the type itself.
4582 if Is_Protected_Type (Scope (Nam))
4583 and then not Is_Variable (Obj)
4584 and then (not Is_Entity_Name (Obj)
4585 or else not Is_Type (Entity (Obj)))
4586 then
4587 Error_Msg_N
4589 Entry_Name);
4590 end if;
4592 Actuals := Parameter_Associations (N);
4593 First_Named := First_Named_Actual (N);
4595 Rewrite (N,
4596 Make_Entry_Call_Statement (Loc,
4597 Name => Entry_Name,
4598 Parameter_Associations => Actuals));
4600 Set_First_Named_Actual (N, First_Named);
4601 Set_Analyzed (N, True);
4603 -- Protected functions can return on the secondary stack, in which
4604 -- case we must trigger the transient scope mechanism
4606 elsif Expander_Active
4607 and then Requires_Transient_Scope (Etype (Nam))
4608 then
4609 Establish_Transient_Scope (N,
4610 Sec_Stack => not Functions_Return_By_DSP_On_Target);
4611 end if;
4612 end Resolve_Entry_Call;
4614 -------------------------
4615 -- Resolve_Equality_Op --
4616 -------------------------
4618 -- Both arguments must have the same type, and the boolean context
4619 -- does not participate in the resolution. The first pass verifies
4620 -- that the interpretation is not ambiguous, and the type of the left
4621 -- argument is correctly set, or is Any_Type in case of ambiguity.
4622 -- If both arguments are strings or aggregates, allocators, or Null,
4623 -- they are ambiguous even though they carry a single (universal) type.
4624 -- Diagnose this case here.
4626 procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id) is
4627 L : constant Node_Id := Left_Opnd (N);
4628 R : constant Node_Id := Right_Opnd (N);
4629 T : Entity_Id := Find_Unique_Type (L, R);
4631 function Find_Unique_Access_Type return Entity_Id;
4632 -- In the case of allocators, make a last-ditch attempt to find a single
4633 -- access type with the right designated type. This is semantically
4634 -- dubious, and of no interest to any real code, but c48008a makes it
4635 -- all worthwhile.
4637 -----------------------------
4638 -- Find_Unique_Access_Type --
4639 -----------------------------
4641 function Find_Unique_Access_Type return Entity_Id is
4642 Acc : Entity_Id;
4643 E : Entity_Id;
4644 S : Entity_Id := Current_Scope;
4646 begin
4647 if Ekind (Etype (R)) = E_Allocator_Type then
4648 Acc := Designated_Type (Etype (R));
4650 elsif Ekind (Etype (L)) = E_Allocator_Type then
4651 Acc := Designated_Type (Etype (L));
4653 else
4654 return Empty;
4655 end if;
4657 while S /= Standard_Standard loop
4658 E := First_Entity (S);
4660 while Present (E) loop
4662 if Is_Type (E)
4663 and then Is_Access_Type (E)
4664 and then Ekind (E) /= E_Allocator_Type
4665 and then Designated_Type (E) = Base_Type (Acc)
4666 then
4667 return E;
4668 end if;
4670 Next_Entity (E);
4671 end loop;
4673 S := Scope (S);
4674 end loop;
4676 return Empty;
4677 end Find_Unique_Access_Type;
4679 -- Start of processing for Resolve_Equality_Op
4681 begin
4682 Check_Direct_Boolean_Op (N);
4684 Set_Etype (N, Base_Type (Typ));
4685 Generate_Reference (T, N, ' ');
4687 if T = Any_Fixed then
4688 T := Unique_Fixed_Point_Type (L);
4689 end if;
4691 if T /= Any_Type then
4693 if T = Any_String
4694 or else T = Any_Composite
4695 or else T = Any_Character
4696 then
4698 if T = Any_Character then
4699 Ambiguous_Character (L);
4700 else
4702 end if;
4704 Set_Etype (N, Any_Type);
4705 return;
4707 elsif T = Any_Access
4708 or else Ekind (T) = E_Allocator_Type
4709 then
4710 T := Find_Unique_Access_Type;
4712 if No (T) then
4714 Set_Etype (N, Any_Type);
4715 return;
4716 end if;
4717 end if;
4719 if Comes_From_Source (N)
4720 and then Has_Unchecked_Union (T)
4721 then
4722 Error_Msg_N
4724 end if;
4726 Resolve (L, T);
4727 Resolve (R, T);
4729 if Warn_On_Redundant_Constructs
4730 and then Comes_From_Source (N)
4731 and then Is_Entity_Name (R)
4732 and then Entity (R) = Standard_True
4733 and then Comes_From_Source (R)
4734 then
4736 end if;
4738 Check_Unset_Reference (L);
4739 Check_Unset_Reference (R);
4740 Generate_Operator_Reference (N, T);
4742 -- If this is an inequality, it may be the implicit inequality
4743 -- created for a user-defined operation, in which case the corres-
4744 -- ponding equality operation is not intrinsic, and the operation
4745 -- cannot be constant-folded. Else fold.
4747 if Nkind (N) = N_Op_Eq
4748 or else Comes_From_Source (Entity (N))
4749 or else Ekind (Entity (N)) = E_Operator
4750 or else Is_Intrinsic_Subprogram
4751 (Corresponding_Equality (Entity (N)))
4752 then
4753 Eval_Relational_Op (N);
4754 elsif Nkind (N) = N_Op_Ne
4755 and then Is_Abstract (Entity (N))
4756 then
4758 end if;
4759 end if;
4760 end Resolve_Equality_Op;
4762 ----------------------------------
4763 -- Resolve_Explicit_Dereference --
4764 ----------------------------------
4766 procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id) is
4767 P : constant Node_Id := Prefix (N);
4768 I : Interp_Index;
4769 It : Interp;
4771 begin
4772 -- Now that we know the type, check that this is not a
4773 -- dereference of an uncompleted type. Note that this
4774 -- is not entirely correct, because dereferences of
4775 -- private types are legal in default expressions.
4776 -- This consideration also applies to similar checks
4777 -- for allocators, qualified expressions, and type
4778 -- conversions. ???
4780 Check_Fully_Declared (Typ, N);
4782 if Is_Overloaded (P) then
4784 -- Use the context type to select the prefix that has the
4785 -- correct designated type.
4787 Get_First_Interp (P, I, It);
4788 while Present (It.Typ) loop
4789 exit when Is_Access_Type (It.Typ)
4790 and then Covers (Typ, Designated_Type (It.Typ));
4792 Get_Next_Interp (I, It);
4793 end loop;
4795 Resolve (P, It.Typ);
4796 Set_Etype (N, Designated_Type (It.Typ));
4798 else
4799 Resolve (P);
4800 end if;
4802 if Is_Access_Type (Etype (P)) then
4803 Apply_Access_Check (N);
4804 end if;
4806 -- If the designated type is a packed unconstrained array type,
4807 -- and the explicit dereference is not in the context of an
4808 -- attribute reference, then we must compute and set the actual
4809 -- subtype, since it is needed by Gigi. The reason we exclude
4810 -- the attribute case is that this is handled fine by Gigi, and
4811 -- in fact we use such attributes to build the actual subtype.
4812 -- We also exclude generated code (which builds actual subtypes
4813 -- directly if they are needed).
4815 if Is_Array_Type (Etype (N))
4816 and then Is_Packed (Etype (N))
4817 and then not Is_Constrained (Etype (N))
4818 and then Nkind (Parent (N)) /= N_Attribute_Reference
4819 and then Comes_From_Source (N)
4820 then
4821 Set_Etype (N, Get_Actual_Subtype (N));
4822 end if;
4824 -- Note: there is no Eval processing required for an explicit
4825 -- deference, because the type is known to be an allocators, and
4826 -- allocator expressions can never be static.
4828 end Resolve_Explicit_Dereference;
4830 -------------------------------
4831 -- Resolve_Indexed_Component --
4832 -------------------------------
4834 procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id) is
4835 Name : constant Node_Id := Prefix (N);
4836 Expr : Node_Id;
4837 Array_Type : Entity_Id := Empty; -- to prevent junk warning
4838 Index : Node_Id;
4840 begin
4841 if Is_Overloaded (Name) then
4843 -- Use the context type to select the prefix that yields the
4844 -- correct component type.
4846 declare
4847 I : Interp_Index;
4848 It : Interp;
4849 I1 : Interp_Index := 0;
4850 P : constant Node_Id := Prefix (N);
4851 Found : Boolean := False;
4853 begin
4854 Get_First_Interp (P, I, It);
4856 while Present (It.Typ) loop
4858 if (Is_Array_Type (It.Typ)
4859 and then Covers (Typ, Component_Type (It.Typ)))
4860 or else (Is_Access_Type (It.Typ)
4861 and then Is_Array_Type (Designated_Type (It.Typ))
4862 and then Covers
4863 (Typ, Component_Type (Designated_Type (It.Typ))))
4864 then
4865 if Found then
4866 It := Disambiguate (P, I1, I, Any_Type);
4868 if It = No_Interp then
4870 Set_Etype (N, Typ);
4871 return;
4873 else
4874 Found := True;
4875 Array_Type := It.Typ;
4876 I1 := I;
4877 end if;
4879 else
4880 Found := True;
4881 Array_Type := It.Typ;
4882 I1 := I;
4883 end if;
4884 end if;
4886 Get_Next_Interp (I, It);
4887 end loop;
4888 end;
4890 else
4891 Array_Type := Etype (Name);
4892 end if;
4894 Resolve (Name, Array_Type);
4895 Array_Type := Get_Actual_Subtype_If_Available (Name);
4897 -- If prefix is access type, dereference to get real array type.
4898 -- Note: we do not apply an access check because the expander always
4899 -- introduces an explicit dereference, and the check will happen there.
4901 if Is_Access_Type (Array_Type) then
4902 Array_Type := Designated_Type (Array_Type);
4903 end if;
4905 -- If name was overloaded, set component type correctly now.
4907 Set_Etype (N, Component_Type (Array_Type));
4909 Index := First_Index (Array_Type);
4910 Expr := First (Expressions (N));
4912 -- The prefix may have resolved to a string literal, in which case
4913 -- its etype has a special representation. This is only possible
4914 -- currently if the prefix is a static concatenation, written in
4915 -- functional notation.
4917 if Ekind (Array_Type) = E_String_Literal_Subtype then
4918 Resolve (Expr, Standard_Positive);
4920 else
4921 while Present (Index) and Present (Expr) loop
4922 Resolve (Expr, Etype (Index));
4923 Check_Unset_Reference (Expr);
4925 if Is_Scalar_Type (Etype (Expr)) then
4926 Apply_Scalar_Range_Check (Expr, Etype (Index));
4927 else
4928 Apply_Range_Check (Expr, Get_Actual_Subtype (Index));
4929 end if;
4931 Next_Index (Index);
4932 Next (Expr);
4933 end loop;
4934 end if;
4936 Eval_Indexed_Component (N);
4937 end Resolve_Indexed_Component;
4939 -----------------------------
4940 -- Resolve_Integer_Literal --
4941 -----------------------------
4943 procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id) is
4944 begin
4945 Set_Etype (N, Typ);
4946 Eval_Integer_Literal (N);
4947 end Resolve_Integer_Literal;
4949 ---------------------------------
4950 -- Resolve_Intrinsic_Operator --
4951 ---------------------------------
4953 procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id) is
4954 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
4955 Op : Entity_Id;
4956 Arg1 : Node_Id;
4957 Arg2 : Node_Id;
4959 begin
4960 Op := Entity (N);
4962 while Scope (Op) /= Standard_Standard loop
4963 Op := Homonym (Op);
4964 pragma Assert (Present (Op));
4965 end loop;
4967 Set_Entity (N, Op);
4968 Set_Is_Overloaded (N, False);
4970 -- If the operand type is private, rewrite with suitable
4971 -- conversions on the operands and the result, to expose
4972 -- the proper underlying numeric type.
4974 if Is_Private_Type (Typ) then
4975 Arg1 := Unchecked_Convert_To (Btyp, Left_Opnd (N));
4977 if Nkind (N) = N_Op_Expon then
4978 Arg2 := Unchecked_Convert_To (Standard_Integer, Right_Opnd (N));
4979 else
4980 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
4981 end if;
4983 Save_Interps (Left_Opnd (N), Expression (Arg1));
4984 Save_Interps (Right_Opnd (N), Expression (Arg2));
4986 Set_Left_Opnd (N, Arg1);
4987 Set_Right_Opnd (N, Arg2);
4989 Set_Etype (N, Btyp);
4990 Rewrite (N, Unchecked_Convert_To (Typ, N));
4991 Resolve (N, Typ);
4993 elsif Typ /= Etype (Left_Opnd (N))
4994 or else Typ /= Etype (Right_Opnd (N))
4995 then
4996 -- Add explicit conversion where needed, and save interpretations
4997 -- in case operands are overloaded.
4999 Arg1 := Convert_To (Typ, Left_Opnd (N));
5000 Arg2 := Convert_To (Typ, Right_Opnd (N));
5002 if Nkind (Arg1) = N_Type_Conversion then
5003 Save_Interps (Left_Opnd (N), Expression (Arg1));
5004 else
5005 Save_Interps (Left_Opnd (N), Arg1);
5006 end if;
5008 if Nkind (Arg2) = N_Type_Conversion then
5009 Save_Interps (Right_Opnd (N), Expression (Arg2));
5010 else
5011 Save_Interps (Right_Opnd (N), Arg1);
5012 end if;
5014 Rewrite (Left_Opnd (N), Arg1);
5015 Rewrite (Right_Opnd (N), Arg2);
5016 Analyze (Arg1);
5017 Analyze (Arg2);
5018 Resolve_Arithmetic_Op (N, Typ);
5020 else
5021 Resolve_Arithmetic_Op (N, Typ);
5022 end if;
5023 end Resolve_Intrinsic_Operator;
5025 --------------------------------------
5026 -- Resolve_Intrinsic_Unary_Operator --
5027 --------------------------------------
5029 procedure Resolve_Intrinsic_Unary_Operator
5030 (N : Node_Id;
5031 Typ : Entity_Id)
5032 is
5033 Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
5034 Op : Entity_Id;
5035 Arg2 : Node_Id;
5037 begin
5038 Op := Entity (N);
5040 while Scope (Op) /= Standard_Standard loop
5041 Op := Homonym (Op);
5042 pragma Assert (Present (Op));
5043 end loop;
5045 Set_Entity (N, Op);
5047 if Is_Private_Type (Typ) then
5048 Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
5049 Save_Interps (Right_Opnd (N), Expression (Arg2));
5051 Set_Right_Opnd (N, Arg2);
5053 Set_Etype (N, Btyp);
5054 Rewrite (N, Unchecked_Convert_To (Typ, N));
5055 Resolve (N, Typ);
5057 else
5058 Resolve_Unary_Op (N, Typ);
5059 end if;
5060 end Resolve_Intrinsic_Unary_Operator;
5062 ------------------------
5063 -- Resolve_Logical_Op --
5064 ------------------------
5066 procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id) is
5067 B_Typ : Entity_Id;
5069 begin
5070 Check_Direct_Boolean_Op (N);
5072 -- Predefined operations on scalar types yield the base type. On
5073 -- the other hand, logical operations on arrays yield the type of
5074 -- the arguments (and the context).
5076 if Is_Array_Type (Typ) then
5077 B_Typ := Typ;
5078 else
5079 B_Typ := Base_Type (Typ);
5080 end if;
5082 -- The following test is required because the operands of the operation
5083 -- may be literals, in which case the resulting type appears to be
5084 -- compatible with a signed integer type, when in fact it is compatible
5085 -- only with modular types. If the context itself is universal, the
5086 -- operation is illegal.
5088 if not Valid_Boolean_Arg (Typ) then
5090 Set_Etype (N, Any_Type);
5091 return;
5093 elsif Typ = Any_Modular then
5094 Error_Msg_N
5096 Set_Etype (N, Any_Type);
5097 return;
5098 elsif Is_Modular_Integer_Type (Typ)
5099 and then Etype (Left_Opnd (N)) = Universal_Integer
5100 and then Etype (Right_Opnd (N)) = Universal_Integer
5101 then
5102 Check_For_Visible_Operator (N, B_Typ);
5103 end if;
5105 Resolve (Left_Opnd (N), B_Typ);
5106 Resolve (Right_Opnd (N), B_Typ);
5108 Check_Unset_Reference (Left_Opnd (N));
5109 Check_Unset_Reference (Right_Opnd (N));
5111 Set_Etype (N, B_Typ);
5112 Generate_Operator_Reference (N, B_Typ);
5113 Eval_Logical_Op (N);
5114 end Resolve_Logical_Op;
5116 ---------------------------
5117 -- Resolve_Membership_Op --
5118 ---------------------------
5120 -- The context can only be a boolean type, and does not determine
5121 -- the arguments. Arguments should be unambiguous, but the preference
5122 -- rule for universal types applies.
5124 procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id) is
5125 pragma Warnings (Off, Typ);
5127 L : constant Node_Id := Left_Opnd (N);
5128 R : constant Node_Id := Right_Opnd (N);
5129 T : Entity_Id;
5131 begin
5132 if L = Error or else R = Error then
5133 return;
5134 end if;
5136 if not Is_Overloaded (R)
5137 and then
5138 (Etype (R) = Universal_Integer or else
5139 Etype (R) = Universal_Real)
5140 and then Is_Overloaded (L)
5141 then
5142 T := Etype (R);
5143 else
5144 T := Intersect_Types (L, R);
5145 end if;
5147 Resolve (L, T);
5148 Check_Unset_Reference (L);
5150 if Nkind (R) = N_Range
5151 and then not Is_Scalar_Type (T)
5152 then
5154 end if;
5156 if Is_Entity_Name (R) then
5157 Freeze_Expression (R);
5158 else
5159 Resolve (R, T);
5160 Check_Unset_Reference (R);
5161 end if;
5163 Eval_Membership_Op (N);
5164 end Resolve_Membership_Op;
5166 ------------------
5167 -- Resolve_Null --
5168 ------------------
5170 procedure Resolve_Null (N : Node_Id; Typ : Entity_Id) is
5171 begin
5172 -- For now allow circumvention of the restriction against
5173 -- anonymous null access values via a debug switch to allow
5174 -- for easier transition.
5176 -- Ada 0Y (AI-231): Remove restriction
5178 if not Extensions_Allowed
5179 and then not Debug_Flag_J
5180 and then Ekind (Typ) = E_Anonymous_Access_Type
5181 and then Comes_From_Source (N)
5182 then
5183 -- In the common case of a call which uses an explicitly null
5184 -- value for an access parameter, give specialized error msg
5186 if Nkind (Parent (N)) = N_Procedure_Call_Statement
5187 or else
5188 Nkind (Parent (N)) = N_Function_Call
5189 then
5190 Error_Msg_N
5193 -- Standard message for all other cases (are there any?)
5195 else
5196 Error_Msg_N
5198 end if;
5199 end if;
5201 -- In a distributed context, null for a remote access to subprogram
5202 -- may need to be replaced with a special record aggregate. In this
5203 -- case, return after having done the transformation.
5205 if (Ekind (Typ) = E_Record_Type
5206 or else Is_Remote_Access_To_Subprogram_Type (Typ))
5207 and then Remote_AST_Null_Value (N, Typ)
5208 then
5209 return;
5210 end if;
5212 -- The null literal takes its type from the context.
5214 Set_Etype (N, Typ);
5215 end Resolve_Null;
5217 -----------------------
5218 -- Resolve_Op_Concat --
5219 -----------------------
5221 procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id) is
5222 Btyp : constant Entity_Id := Base_Type (Typ);
5223 Op1 : constant Node_Id := Left_Opnd (N);
5224 Op2 : constant Node_Id := Right_Opnd (N);
5226 procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean);
5227 -- Internal procedure to resolve one operand of concatenation operator.
5228 -- The operand is either of the array type or of the component type.
5229 -- If the operand is an aggregate, and the component type is composite,
5230 -- this is ambiguous if component type has aggregates.
5232 -------------------------------
5233 -- Resolve_Concatenation_Arg --
5234 -------------------------------
5236 procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean) is
5237 begin
5238 if In_Instance then
5239 if Is_Comp
5240 or else (not Is_Overloaded (Arg)
5241 and then Etype (Arg) /= Any_Composite
5242 and then Covers (Component_Type (Typ), Etype (Arg)))
5243 then
5244 Resolve (Arg, Component_Type (Typ));
5245 else
5246 Resolve (Arg, Btyp);
5247 end if;
5249 elsif Has_Compatible_Type (Arg, Component_Type (Typ)) then
5251 if Nkind (Arg) = N_Aggregate
5252 and then Is_Composite_Type (Component_Type (Typ))
5253 then
5254 if Is_Private_Type (Component_Type (Typ)) then
5255 Resolve (Arg, Btyp);
5257 else
5259 Set_Etype (Arg, Any_Type);
5260 end if;
5262 else
5263 if Is_Overloaded (Arg)
5264 and then Has_Compatible_Type (Arg, Typ)
5265 and then Etype (Arg) /= Any_Type
5266 then
5269 declare
5270 I : Interp_Index;
5271 It : Interp;
5273 begin
5274 Get_First_Interp (Arg, I, It);
5276 while Present (It.Nam) loop
5278 if Base_Type (Etype (It.Nam)) = Base_Type (Typ)
5279 or else Base_Type (Etype (It.Nam)) =
5280 Base_Type (Component_Type (Typ))
5281 then
5282 Error_Msg_Sloc := Sloc (It.Nam);
5284 end if;
5286 Get_Next_Interp (I, It);
5287 end loop;
5288 end;
5289 end if;
5291 Resolve (Arg, Component_Type (Typ));
5293 if Nkind (Arg) = N_String_Literal then
5294 Set_Etype (Arg, Component_Type (Typ));
5295 end if;
5297 if Arg = Left_Opnd (N) then
5298 Set_Is_Component_Left_Opnd (N);
5299 else
5300 Set_Is_Component_Right_Opnd (N);
5301 end if;
5302 end if;
5304 else
5305 Resolve (Arg, Btyp);
5306 end if;
5308 Check_Unset_Reference (Arg);
5309 end Resolve_Concatenation_Arg;
5311 -- Start of processing for Resolve_Op_Concat
5313 begin
5314 Set_Etype (N, Btyp);
5316 if Is_Limited_Composite (Btyp) then
5318 Explain_Limited_Type (Btyp, N);
5319 end if;
5321 -- If the operands are themselves concatenations, resolve them as
5322 -- such directly. This removes several layers of recursion and allows
5323 -- GNAT to handle larger multiple concatenations.
5325 if Nkind (Op1) = N_Op_Concat
5326 and then not Is_Array_Type (Component_Type (Typ))
5327 and then Entity (Op1) = Entity (N)
5328 then
5329 Resolve_Op_Concat (Op1, Typ);
5330 else
5331 Resolve_Concatenation_Arg
5332 (Op1, Is_Component_Left_Opnd (N));
5333 end if;
5335 if Nkind (Op2) = N_Op_Concat
5336 and then not Is_Array_Type (Component_Type (Typ))
5337 and then Entity (Op2) = Entity (N)
5338 then
5339 Resolve_Op_Concat (Op2, Typ);
5340 else
5341 Resolve_Concatenation_Arg
5342 (Op2, Is_Component_Right_Opnd (N));
5343 end if;
5345 Generate_Operator_Reference (N, Typ);
5347 if Is_String_Type (Typ) then
5348 Eval_Concatenation (N);
5349 end if;
5351 -- If this is not a static concatenation, but the result is a
5352 -- string type (and not an array of strings) insure that static
5353 -- string operands have their subtypes properly constructed.
5355 if Nkind (N) /= N_String_Literal
5356 and then Is_Character_Type (Component_Type (Typ))
5357 then
5358 Set_String_Literal_Subtype (Op1, Typ);
5359 Set_String_Literal_Subtype (Op2, Typ);
5360 end if;
5361 end Resolve_Op_Concat;
5363 ----------------------
5364 -- Resolve_Op_Expon --
5365 ----------------------
5367 procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id) is
5368 B_Typ : constant Entity_Id := Base_Type (Typ);
5370 begin
5371 -- Catch attempts to do fixed-point exponentation with universal
5372 -- operands, which is a case where the illegality is not caught
5373 -- during normal operator analysis.
5375 if Is_Fixed_Point_Type (Typ) and then Comes_From_Source (N) then
5377 return;
5378 end if;
5380 if Comes_From_Source (N)
5381 and then Ekind (Entity (N)) = E_Function
5382 and then Is_Imported (Entity (N))
5383 and then Is_Intrinsic_Subprogram (Entity (N))
5384 then
5385 Resolve_Intrinsic_Operator (N, Typ);
5386 return;
5387 end if;
5389 if Etype (Left_Opnd (N)) = Universal_Integer
5390 or else Etype (Left_Opnd (N)) = Universal_Real
5391 then
5392 Check_For_Visible_Operator (N, B_Typ);
5393 end if;
5395 -- We do the resolution using the base type, because intermediate values
5396 -- in expressions always are of the base type, not a subtype of it.
5398 Resolve (Left_Opnd (N), B_Typ);
5399 Resolve (Right_Opnd (N), Standard_Integer);
5401 Check_Unset_Reference (Left_Opnd (N));
5402 Check_Unset_Reference (Right_Opnd (N));
5404 Set_Etype (N, B_Typ);
5405 Generate_Operator_Reference (N, B_Typ);
5406 Eval_Op_Expon (N);
5408 -- Set overflow checking bit. Much cleverer code needed here eventually
5409 -- and perhaps the Resolve routines should be separated for the various
5410 -- arithmetic operations, since they will need different processing. ???
5412 if Nkind (N) in N_Op then
5413 if not Overflow_Checks_Suppressed (Etype (N)) then
5414 Enable_Overflow_Check (N);
5415 end if;
5416 end if;
5417 end Resolve_Op_Expon;
5419 --------------------
5420 -- Resolve_Op_Not --
5421 --------------------
5423 procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id) is
5424 B_Typ : Entity_Id;
5426 function Parent_Is_Boolean return Boolean;
5427 -- This function determines if the parent node is a boolean operator
5428 -- or operation (comparison op, membership test, or short circuit form)
5429 -- and the not in question is the left operand of this operation.
5430 -- Note that if the not is in parens, then false is returned.
5432 function Parent_Is_Boolean return Boolean is
5433 begin
5434 if Paren_Count (N) /= 0 then
5435 return False;
5437 else
5438 case Nkind (Parent (N)) is
5439 when N_Op_And |
5440 N_Op_Eq |
5441 N_Op_Ge |
5442 N_Op_Gt |
5443 N_Op_Le |
5444 N_Op_Lt |
5445 N_Op_Ne |
5446 N_Op_Or |
5447 N_Op_Xor |
5448 N_In |
5449 N_Not_In |
5450 N_And_Then |
5451 N_Or_Else =>
5453 return Left_Opnd (Parent (N)) = N;
5455 when others =>
5456 return False;
5457 end case;
5458 end if;
5459 end Parent_Is_Boolean;
5461 -- Start of processing for Resolve_Op_Not
5463 begin
5464 -- Predefined operations on scalar types yield the base type. On
5465 -- the other hand, logical operations on arrays yield the type of
5466 -- the arguments (and the context).
5468 if Is_Array_Type (Typ) then
5469 B_Typ := Typ;
5470 else
5471 B_Typ := Base_Type (Typ);
5472 end if;
5474 if not Valid_Boolean_Arg (Typ) then
5476 Set_Etype (N, Any_Type);
5477 return;
5479 elsif Typ = Universal_Integer or else Typ = Any_Modular then
5480 if Parent_Is_Boolean then
5481 Error_Msg_N
5483 Right_Opnd (N));
5484 else
5485 Error_Msg_N
5487 end if;
5489 Set_Etype (N, Any_Type);
5490 return;
5492 else
5493 if not Is_Boolean_Type (Typ)
5494 and then Parent_Is_Boolean
5495 then
5497 end if;
5499 Resolve (Right_Opnd (N), B_Typ);
5500 Check_Unset_Reference (Right_Opnd (N));
5501 Set_Etype (N, B_Typ);
5502 Generate_Operator_Reference (N, B_Typ);
5503 Eval_Op_Not (N);
5504 end if;
5505 end Resolve_Op_Not;
5507 -----------------------------
5508 -- Resolve_Operator_Symbol --
5509 -----------------------------
5511 -- Nothing to be done, all resolved already
5513 procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id) is
5514 pragma Warnings (Off, N);
5515 pragma Warnings (Off, Typ);
5517 begin
5518 null;
5519 end Resolve_Operator_Symbol;
5521 ----------------------------------
5522 -- Resolve_Qualified_Expression --
5523 ----------------------------------
5525 procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id) is
5526 pragma Warnings (Off, Typ);
5528 Target_Typ : constant Entity_Id := Entity (Subtype_Mark (N));
5529 Expr : constant Node_Id := Expression (N);
5531 begin
5532 Resolve (Expr, Target_Typ);
5534 -- A qualified expression requires an exact match of the type,
5535 -- class-wide matching is not allowed.
5537 if Is_Class_Wide_Type (Target_Typ)
5538 and then Base_Type (Etype (Expr)) /= Base_Type (Target_Typ)
5539 then
5540 Wrong_Type (Expr, Target_Typ);
5541 end if;
5543 -- If the target type is unconstrained, then we reset the type of
5544 -- the result from the type of the expression. For other cases, the
5545 -- actual subtype of the expression is the target type.
5547 if Is_Composite_Type (Target_Typ)
5548 and then not Is_Constrained (Target_Typ)
5549 then
5550 Set_Etype (N, Etype (Expr));
5551 end if;
5553 Eval_Qualified_Expression (N);
5554 end Resolve_Qualified_Expression;
5556 -------------------
5557 -- Resolve_Range --
5558 -------------------
5560 procedure Resolve_Range (N : Node_Id; Typ : Entity_Id) is
5561 L : constant Node_Id := Low_Bound (N);
5562 H : constant Node_Id := High_Bound (N);
5564 begin
5565 Set_Etype (N, Typ);
5566 Resolve (L, Typ);
5567 Resolve (H, Typ);
5569 Check_Unset_Reference (L);
5570 Check_Unset_Reference (H);
5572 -- We have to check the bounds for being within the base range as
5573 -- required for a non-static context. Normally this is automatic
5574 -- and done as part of evaluating expressions, but the N_Range
5575 -- node is an exception, since in GNAT we consider this node to
5576 -- be a subexpression, even though in Ada it is not. The circuit
5577 -- in Sem_Eval could check for this, but that would put the test
5578 -- on the main evaluation path for expressions.
5580 Check_Non_Static_Context (L);
5581 Check_Non_Static_Context (H);
5583 -- If bounds are static, constant-fold them, so size computations
5584 -- are identical between front-end and back-end. Do not perform this
5585 -- transformation while analyzing generic units, as type information
5586 -- would then be lost when reanalyzing the constant node in the
5587 -- instance.
5589 if Is_Discrete_Type (Typ) and then Expander_Active then
5590 if Is_OK_Static_Expression (L) then
5591 Fold_Uint (L, Expr_Value (L), Is_Static_Expression (L));
5592 end if;
5594 if Is_OK_Static_Expression (H) then
5595 Fold_Uint (H, Expr_Value (H), Is_Static_Expression (H));
5596 end if;
5597 end if;
5598 end Resolve_Range;
5600 --------------------------
5601 -- Resolve_Real_Literal --
5602 --------------------------
5604 procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id) is
5605 Actual_Typ : constant Entity_Id := Etype (N);
5607 begin
5608 -- Special processing for fixed-point literals to make sure that the
5609 -- value is an exact multiple of small where this is required. We
5610 -- skip this for the universal real case, and also for generic types.
5612 if Is_Fixed_Point_Type (Typ)
5613 and then Typ /= Universal_Fixed
5614 and then Typ /= Any_Fixed
5615 and then not Is_Generic_Type (Typ)
5616 then
5617 declare
5618 Val : constant Ureal := Realval (N);
5619 Cintr : constant Ureal := Val / Small_Value (Typ);
5620 Cint : constant Uint := UR_Trunc (Cintr);
5621 Den : constant Uint := Norm_Den (Cintr);
5622 Stat : Boolean;
5624 begin
5625 -- Case of literal is not an exact multiple of the Small
5627 if Den /= 1 then
5629 -- For a source program literal for a decimal fixed-point
5630 -- type, this is statically illegal (RM 4.9(36)).
5632 if Is_Decimal_Fixed_Point_Type (Typ)
5633 and then Actual_Typ = Universal_Real
5634 and then Comes_From_Source (N)
5635 then
5637 end if;
5639 -- Replace literal by a value that is the exact representation
5640 -- of a value of the type, i.e. a multiple of the small value,
5641 -- by truncation, since Machine_Rounds is false for all GNAT
5642 -- fixed-point types (RM 4.9(38)).
5644 Stat := Is_Static_Expression (N);
5645 Rewrite (N,
5646 Make_Real_Literal (Sloc (N),
5647 Realval => Small_Value (Typ) * Cint));
5649 Set_Is_Static_Expression (N, Stat);
5650 end if;
5652 -- In all cases, set the corresponding integer field
5654 Set_Corresponding_Integer_Value (N, Cint);
5655 end;
5656 end if;
5658 -- Now replace the actual type by the expected type as usual
5660 Set_Etype (N, Typ);
5661 Eval_Real_Literal (N);
5662 end Resolve_Real_Literal;
5664 -----------------------
5665 -- Resolve_Reference --
5666 -----------------------
5668 procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id) is
5669 P : constant Node_Id := Prefix (N);
5671 begin
5672 -- Replace general access with specific type
5674 if Ekind (Etype (N)) = E_Allocator_Type then
5675 Set_Etype (N, Base_Type (Typ));
5676 end if;
5678 Resolve (P, Designated_Type (Etype (N)));
5680 -- If we are taking the reference of a volatile entity, then treat
5681 -- it as a potential modification of this entity. This is much too
5682 -- conservative, but is necessary because remove side effects can
5683 -- result in transformations of normal assignments into reference
5684 -- sequences that otherwise fail to notice the modification.
5686 if Is_Entity_Name (P) and then Treat_As_Volatile (Entity (P)) then
5687 Note_Possible_Modification (P);
5688 end if;
5689 end Resolve_Reference;
5691 --------------------------------
5692 -- Resolve_Selected_Component --
5693 --------------------------------
5695 procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id) is
5696 Comp : Entity_Id;
5697 Comp1 : Entity_Id := Empty; -- prevent junk warning
5698 P : constant Node_Id := Prefix (N);
5699 S : constant Node_Id := Selector_Name (N);
5700 T : Entity_Id := Etype (P);
5701 I : Interp_Index;
5702 I1 : Interp_Index := 0; -- prevent junk warning
5703 It : Interp;
5704 It1 : Interp;
5705 Found : Boolean;
5707 function Init_Component return Boolean;
5708 -- Check whether this is the initialization of a component within an
5709 -- init proc (by assignment or call to another init proc). If true,
5710 -- there is no need for a discriminant check.
5712 --------------------
5713 -- Init_Component --
5714 --------------------
5716 function Init_Component return Boolean is
5717 begin
5718 return Inside_Init_Proc
5719 and then Nkind (Prefix (N)) = N_Identifier
5720 and then Chars (Prefix (N)) = Name_uInit
5721 and then Nkind (Parent (Parent (N))) = N_Case_Statement_Alternative;
5722 end Init_Component;
5724 -- Start of processing for Resolve_Selected_Component
5726 begin
5727 if Is_Overloaded (P) then
5729 -- Use the context type to select the prefix that has a selector
5730 -- of the correct name and type.
5732 Found := False;
5733 Get_First_Interp (P, I, It);
5735 Search : while Present (It.Typ) loop
5736 if Is_Access_Type (It.Typ) then
5737 T := Designated_Type (It.Typ);
5738 else
5739 T := It.Typ;
5740 end if;
5742 if Is_Record_Type (T) then
5743 Comp := First_Entity (T);
5745 while Present (Comp) loop
5747 if Chars (Comp) = Chars (S)
5748 and then Covers (Etype (Comp), Typ)
5749 then
5750 if not Found then
5751 Found := True;
5752 I1 := I;
5753 It1 := It;
5754 Comp1 := Comp;
5756 else
5757 It := Disambiguate (P, I1, I, Any_Type);
5759 if It = No_Interp then
5760 Error_Msg_N
5762 Set_Etype (N, Typ);
5763 return;
5765 else
5766 It1 := It;
5768 if Scope (Comp1) /= It1.Typ then
5770 -- Resolution chooses the new interpretation.
5771 -- Find the component with the right name.
5773 Comp1 := First_Entity (It1.Typ);
5775 while Present (Comp1)
5776 and then Chars (Comp1) /= Chars (S)
5777 loop
5778 Comp1 := Next_Entity (Comp1);
5779 end loop;
5780 end if;
5782 exit Search;
5783 end if;
5784 end if;
5785 end if;
5787 Comp := Next_Entity (Comp);
5788 end loop;
5790 end if;
5792 Get_Next_Interp (I, It);
5793 end loop Search;
5795 Resolve (P, It1.Typ);
5796 Set_Etype (N, Typ);
5797 Set_Entity (S, Comp1);
5799 else
5800 -- Resolve prefix with its type
5802 Resolve (P, T);
5803 end if;
5805 -- Deal with access type case
5807 if Is_Access_Type (Etype (P)) then
5808 Apply_Access_Check (N);
5809 T := Designated_Type (Etype (P));
5810 else
5811 T := Etype (P);
5812 end if;
5814 if Has_Discriminants (T)
5815 and then (Ekind (Entity (S)) = E_Component
5816 or else
5817 Ekind (Entity (S)) = E_Discriminant)
5818 and then Present (Original_Record_Component (Entity (S)))
5819 and then Ekind (Original_Record_Component (Entity (S))) = E_Component
5820 and then Present (Discriminant_Checking_Func
5821 (Original_Record_Component (Entity (S))))
5822 and then not Discriminant_Checks_Suppressed (T)
5823 and then not Init_Component
5824 then
5825 Set_Do_Discriminant_Check (N);
5826 end if;
5828 if Ekind (Entity (S)) = E_Void then
5830 end if;
5832 -- If the prefix is a record conversion, this may be a renamed
5833 -- discriminant whose bounds differ from those of the original
5834 -- one, so we must ensure that a range check is performed.
5836 if Nkind (P) = N_Type_Conversion
5837 and then Ekind (Entity (S)) = E_Discriminant
5838 and then Is_Discrete_Type (Typ)
5839 then
5840 Set_Etype (N, Base_Type (Typ));
5841 end if;
5843 -- Note: No Eval processing is required, because the prefix is of a
5844 -- record type, or protected type, and neither can possibly be static.
5846 end Resolve_Selected_Component;
5848 -------------------
5849 -- Resolve_Shift --
5850 -------------------
5852 procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id) is
5853 B_Typ : constant Entity_Id := Base_Type (Typ);
5854 L : constant Node_Id := Left_Opnd (N);
5855 R : constant Node_Id := Right_Opnd (N);
5857 begin
5858 -- We do the resolution using the base type, because intermediate values
5859 -- in expressions always are of the base type, not a subtype of it.
5861 Resolve (L, B_Typ);
5862 Resolve (R, Standard_Natural);
5864 Check_Unset_Reference (L);
5865 Check_Unset_Reference (R);
5867 Set_Etype (N, B_Typ);
5868 Generate_Operator_Reference (N, B_Typ);
5869 Eval_Shift (N);
5870 end Resolve_Shift;
5872 ---------------------------
5873 -- Resolve_Short_Circuit --
5874 ---------------------------
5876 procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id) is
5877 B_Typ : constant Entity_Id := Base_Type (Typ);
5878 L : constant Node_Id := Left_Opnd (N);
5879 R : constant Node_Id := Right_Opnd (N);
5881 begin
5882 Resolve (L, B_Typ);
5883 Resolve (R, B_Typ);
5885 Check_Unset_Reference (L);
5886 Check_Unset_Reference (R);
5888 Set_Etype (N, B_Typ);
5889 Eval_Short_Circuit (N);
5890 end Resolve_Short_Circuit;
5892 -------------------
5893 -- Resolve_Slice --
5894 -------------------
5896 procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id) is
5897 Name : constant Node_Id := Prefix (N);
5898 Drange : constant Node_Id := Discrete_Range (N);
5899 Array_Type : Entity_Id := Empty;
5900 Index : Node_Id;
5902 begin
5903 if Is_Overloaded (Name) then
5905 -- Use the context type to select the prefix that yields the
5906 -- correct array type.
5908 declare
5909 I : Interp_Index;
5910 I1 : Interp_Index := 0;
5911 It : Interp;
5912 P : constant Node_Id := Prefix (N);
5913 Found : Boolean := False;
5915 begin
5916 Get_First_Interp (P, I, It);
5918 while Present (It.Typ) loop
5920 if (Is_Array_Type (It.Typ)
5921 and then Covers (Typ, It.Typ))
5922 or else (Is_Access_Type (It.Typ)
5923 and then Is_Array_Type (Designated_Type (It.Typ))
5924 and then Covers (Typ, Designated_Type (It.Typ)))
5925 then
5926 if Found then
5927 It := Disambiguate (P, I1, I, Any_Type);
5929 if It = No_Interp then
5931 Set_Etype (N, Typ);
5932 return;
5933 else
5934 Found := True;
5935 Array_Type := It.Typ;
5936 I1 := I;
5937 end if;
5938 else
5939 Found := True;
5940 Array_Type := It.Typ;
5941 I1 := I;
5942 end if;
5943 end if;
5945 Get_Next_Interp (I, It);
5946 end loop;
5947 end;
5949 else
5950 Array_Type := Etype (Name);
5951 end if;
5953 Resolve (Name, Array_Type);
5955 if Is_Access_Type (Array_Type) then
5956 Apply_Access_Check (N);
5957 Array_Type := Designated_Type (Array_Type);
5959 elsif Is_Entity_Name (Name)
5960 or else (Nkind (Name) = N_Function_Call
5961 and then not Is_Constrained (Etype (Name)))
5962 then
5963 Array_Type := Get_Actual_Subtype (Name);
5964 end if;
5966 -- If name was overloaded, set slice type correctly now
5968 Set_Etype (N, Array_Type);
5970 -- If the range is specified by a subtype mark, no resolution
5971 -- is necessary.
5973 if not Is_Entity_Name (Drange) then
5974 Index := First_Index (Array_Type);
5975 Resolve (Drange, Base_Type (Etype (Index)));
5977 if Nkind (Drange) = N_Range then
5978 Apply_Range_Check (Drange, Etype (Index));
5979 end if;
5980 end if;
5982 Set_Slice_Subtype (N);
5983 Eval_Slice (N);
5984 end Resolve_Slice;
5986 ----------------------------
5987 -- Resolve_String_Literal --
5988 ----------------------------
5990 procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id) is
5991 C_Typ : constant Entity_Id := Component_Type (Typ);
5992 R_Typ : constant Entity_Id := Root_Type (C_Typ);
5993 Loc : constant Source_Ptr := Sloc (N);
5994 Str : constant String_Id := Strval (N);
5995 Strlen : constant Nat := String_Length (Str);
5996 Subtype_Id : Entity_Id;
5997 Need_Check : Boolean;
5999 begin
6000 -- For a string appearing in a concatenation, defer creation of the
6001 -- string_literal_subtype until the end of the resolution of the
6002 -- concatenation, because the literal may be constant-folded away.
6003 -- This is a useful optimization for long concatenation expressions.
6005 -- If the string is an aggregate built for a single character (which
6006 -- happens in a non-static context) or a is null string to which special
6007 -- checks may apply, we build the subtype. Wide strings must also get
6008 -- a string subtype if they come from a one character aggregate. Strings
6009 -- generated by attributes might be static, but it is often hard to
6010 -- determine whether the enclosing context is static, so we generate
6011 -- subtypes for them as well, thus losing some rarer optimizations ???
6012 -- Same for strings that come from a static conversion.
6014 Need_Check :=
6015 (Strlen = 0 and then Typ /= Standard_String)
6016 or else Nkind (Parent (N)) /= N_Op_Concat
6017 or else (N /= Left_Opnd (Parent (N))
6018 and then N /= Right_Opnd (Parent (N)))
6019 or else (Typ = Standard_Wide_String
6020 and then Nkind (Original_Node (N)) /= N_String_Literal);
6022 -- If the resolving type is itself a string literal subtype, we
6023 -- can just reuse it, since there is no point in creating another.
6025 if Ekind (Typ) = E_String_Literal_Subtype then
6026 Subtype_Id := Typ;
6028 elsif Nkind (Parent (N)) = N_Op_Concat
6029 and then not Need_Check
6030 and then Nkind (Original_Node (N)) /= N_Character_Literal
6031 and then Nkind (Original_Node (N)) /= N_Attribute_Reference
6032 and then Nkind (Original_Node (N)) /= N_Qualified_Expression
6033 and then Nkind (Original_Node (N)) /= N_Type_Conversion
6034 then
6035 Subtype_Id := Typ;
6037 -- Otherwise we must create a string literal subtype. Note that the
6038 -- whole idea of string literal subtypes is simply to avoid the need
6039 -- for building a full fledged array subtype for each literal.
6040 else
6041 Set_String_Literal_Subtype (N, Typ);
6042 Subtype_Id := Etype (N);
6043 end if;
6045 if Nkind (Parent (N)) /= N_Op_Concat
6046 or else Need_Check
6047 then
6048 Set_Etype (N, Subtype_Id);
6049 Eval_String_Literal (N);
6050 end if;
6052 if Is_Limited_Composite (Typ)
6053 or else Is_Private_Composite (Typ)
6054 then
6056 Set_Etype (N, Any_Type);
6057 return;
6058 end if;
6060 -- The validity of a null string has been checked in the
6061 -- call to Eval_String_Literal.
6063 if Strlen = 0 then
6064 return;
6066 -- Always accept string literal with component type Any_Character,
6067 -- which occurs in error situations and in comparisons of literals,
6068 -- both of which should accept all literals.
6070 elsif R_Typ = Any_Character then
6071 return;
6073 -- If the type is bit-packed, then we always tranform the string
6074 -- literal into a full fledged aggregate.
6076 elsif Is_Bit_Packed_Array (Typ) then
6077 null;
6079 -- Deal with cases of Wide_String and String
6081 else
6082 -- For Standard.Wide_String, or any other type whose component
6083 -- type is Standard.Wide_Character, we know that all the
6084 -- characters in the string must be acceptable, since the parser
6085 -- accepted the characters as valid character literals.
6087 if R_Typ = Standard_Wide_Character then
6088 null;
6090 -- For the case of Standard.String, or any other type whose
6091 -- component type is Standard.Character, we must make sure that
6092 -- there are no wide characters in the string, i.e. that it is
6093 -- entirely composed of characters in range of type String.
6095 -- If the string literal is the result of a static concatenation,
6096 -- the test has already been performed on the components, and need
6097 -- not be repeated.
6099 elsif R_Typ = Standard_Character
6100 and then Nkind (Original_Node (N)) /= N_Op_Concat
6101 then
6102 for J in 1 .. Strlen loop
6103 if not In_Character_Range (Get_String_Char (Str, J)) then
6105 -- If we are out of range, post error. This is one of the
6106 -- very few places that we place the flag in the middle of
6107 -- a token, right under the offending wide character.
6109 Error_Msg
6111 Source_Ptr (Int (Loc) + J));
6112 return;
6113 end if;
6114 end loop;
6116 -- If the root type is not a standard character, then we will convert
6117 -- the string into an aggregate and will let the aggregate code do
6118 -- the checking.
6120 else
6121 null;
6123 end if;
6125 -- See if the component type of the array corresponding to the
6126 -- string has compile time known bounds. If yes we can directly
6127 -- check whether the evaluation of the string will raise constraint
6128 -- error. Otherwise we need to transform the string literal into
6129 -- the corresponding character aggregate and let the aggregate
6130 -- code do the checking.
6132 if R_Typ = Standard_Wide_Character
6133 or else R_Typ = Standard_Character
6134 then
6135 -- Check for the case of full range, where we are definitely OK
6137 if Component_Type (Typ) = Base_Type (Component_Type (Typ)) then
6138 return;
6139 end if;
6141 -- Here the range is not the complete base type range, so check
6143 declare
6144 Comp_Typ_Lo : constant Node_Id :=
6145 Type_Low_Bound (Component_Type (Typ));
6146 Comp_Typ_Hi : constant Node_Id :=
6147 Type_High_Bound (Component_Type (Typ));
6149 Char_Val : Uint;
6151 begin
6152 if Compile_Time_Known_Value (Comp_Typ_Lo)
6153 and then Compile_Time_Known_Value (Comp_Typ_Hi)
6154 then
6155 for J in 1 .. Strlen loop
6156 Char_Val := UI_From_Int (Int (Get_String_Char (Str, J)));
6158 if Char_Val < Expr_Value (Comp_Typ_Lo)
6159 or else Char_Val > Expr_Value (Comp_Typ_Hi)
6160 then
6161 Apply_Compile_Time_Constraint_Error
6163 Loc => Source_Ptr (Int (Loc) + J));
6164 end if;
6165 end loop;
6167 return;
6168 end if;
6169 end;
6170 end if;
6171 end if;
6173 -- If we got here we meed to transform the string literal into the
6174 -- equivalent qualified positional array aggregate. This is rather
6175 -- heavy artillery for this situation, but it is hard work to avoid.
6177 declare
6178 Lits : constant List_Id := New_List;
6179 P : Source_Ptr := Loc + 1;
6180 C : Char_Code;
6182 begin
6183 -- Build the character literals, we give them source locations
6184 -- that correspond to the string positions, which is a bit tricky
6185 -- given the possible presence of wide character escape sequences.
6187 for J in 1 .. Strlen loop
6188 C := Get_String_Char (Str, J);
6189 Set_Character_Literal_Name (C);
6191 Append_To (Lits,
6192 Make_Character_Literal (P, Name_Find, C));
6194 if In_Character_Range (C) then
6195 P := P + 1;
6197 -- Should we have a call to Skip_Wide here ???
6198 -- ??? else
6199 -- Skip_Wide (P);
6201 end if;
6202 end loop;
6204 Rewrite (N,
6205 Make_Qualified_Expression (Loc,
6206 Subtype_Mark => New_Reference_To (Typ, Loc),
6207 Expression =>
6208 Make_Aggregate (Loc, Expressions => Lits)));
6210 Analyze_And_Resolve (N, Typ);
6211 end;
6212 end Resolve_String_Literal;
6214 -----------------------------
6215 -- Resolve_Subprogram_Info --
6216 -----------------------------
6218 procedure Resolve_Subprogram_Info (N : Node_Id; Typ : Entity_Id) is
6219 begin
6220 Set_Etype (N, Typ);
6221 end Resolve_Subprogram_Info;
6223 -----------------------------
6224 -- Resolve_Type_Conversion --
6225 -----------------------------
6227 procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id) is
6228 Target_Type : constant Entity_Id := Etype (N);
6229 Conv_OK : constant Boolean := Conversion_OK (N);
6230 Operand : Node_Id;
6231 Opnd_Type : Entity_Id;
6232 Rop : Node_Id;
6233 Orig_N : Node_Id;
6234 Orig_T : Node_Id;
6236 begin
6237 Operand := Expression (N);
6239 if not Conv_OK
6240 and then not Valid_Conversion (N, Target_Type, Operand)
6241 then
6242 return;
6243 end if;
6245 if Etype (Operand) = Any_Fixed then
6247 -- Mixed-mode operation involving a literal. Context must be a fixed
6248 -- type which is applied to the literal subsequently.
6250 if Is_Fixed_Point_Type (Typ) then
6251 Set_Etype (Operand, Universal_Real);
6253 elsif Is_Numeric_Type (Typ)
6254 and then (Nkind (Operand) = N_Op_Multiply
6255 or else Nkind (Operand) = N_Op_Divide)
6256 and then (Etype (Right_Opnd (Operand)) = Universal_Real
6257 or else Etype (Left_Opnd (Operand)) = Universal_Real)
6258 then
6259 if Unique_Fixed_Point_Type (N) = Any_Type then
6260 return; -- expression is ambiguous.
6261 else
6262 Set_Etype (Operand, Standard_Duration);
6263 end if;
6265 if Etype (Right_Opnd (Operand)) = Universal_Real then
6266 Rop := New_Copy_Tree (Right_Opnd (Operand));
6267 else
6268 Rop := New_Copy_Tree (Left_Opnd (Operand));
6269 end if;
6271 Resolve (Rop, Standard_Long_Long_Float);
6273 if Realval (Rop) /= Ureal_0
6274 and then abs (Realval (Rop)) < Delta_Value (Standard_Duration)
6275 then
6277 Rop);
6279 end if;
6281 elsif Is_Numeric_Type (Typ)
6282 and then Nkind (Operand) in N_Op
6283 and then Unique_Fixed_Point_Type (N) /= Any_Type
6284 then
6285 Set_Etype (Operand, Standard_Duration);
6287 else
6289 Set_Etype (Operand, Any_Type);
6290 return;
6291 end if;
6292 end if;
6294 Opnd_Type := Etype (Operand);
6295 Resolve (Operand);
6297 -- Note: we do the Eval_Type_Conversion call before applying the
6298 -- required checks for a subtype conversion. This is important,
6299 -- since both are prepared under certain circumstances to change
6300 -- the type conversion to a constraint error node, but in the case
6301 -- of Eval_Type_Conversion this may reflect an illegality in the
6302 -- static case, and we would miss the illegality (getting only a
6303 -- warning message), if we applied the type conversion checks first.
6305 Eval_Type_Conversion (N);
6307 -- If after evaluation, we still have a type conversion, then we
6308 -- may need to apply checks required for a subtype conversion.
6310 -- Skip these type conversion checks if universal fixed operands
6311 -- operands involved, since range checks are handled separately for
6312 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
6314 if Nkind (N) = N_Type_Conversion
6315 and then not Is_Generic_Type (Root_Type (Target_Type))
6316 and then Target_Type /= Universal_Fixed
6317 and then Opnd_Type /= Universal_Fixed
6318 then
6319 Apply_Type_Conversion_Checks (N);
6320 end if;
6322 -- Issue warning for conversion of simple object to its own type
6323 -- We have to test the original nodes, since they may have been
6324 -- rewritten by various optimizations.
6326 Orig_N := Original_Node (N);
6328 if Warn_On_Redundant_Constructs
6329 and then Comes_From_Source (Orig_N)
6330 and then Nkind (Orig_N) = N_Type_Conversion
6331 then
6332 Orig_N := Original_Node (Expression (Orig_N));
6333 Orig_T := Target_Type;
6335 -- If the node is part of a larger expression, the Target_Type
6336 -- may not be the original type of the node if the context is a
6337 -- condition. Recover original type to see if conversion is needed.
6339 if Is_Boolean_Type (Orig_T)
6340 and then Nkind (Parent (N)) in N_Op
6341 then
6342 Orig_T := Etype (Parent (N));
6343 end if;
6345 if Is_Entity_Name (Orig_N)
6346 and then Etype (Entity (Orig_N)) = Orig_T
6347 then
6348 Error_Msg_NE
6350 end if;
6351 end if;
6352 end Resolve_Type_Conversion;
6354 ----------------------
6355 -- Resolve_Unary_Op --
6356 ----------------------
6358 procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id) is
6359 B_Typ : constant Entity_Id := Base_Type (Typ);
6360 R : constant Node_Id := Right_Opnd (N);
6361 OK : Boolean;
6362 Lo : Uint;
6363 Hi : Uint;
6365 begin
6366 -- Generate warning for expressions like abs (x mod 2)
6368 if Warn_On_Redundant_Constructs
6369 and then Nkind (N) = N_Op_Abs
6370 then
6371 Determine_Range (Right_Opnd (N), OK, Lo, Hi);
6373 if OK and then Hi >= Lo and then Lo >= 0 then
6374 Error_Msg_N
6376 end if;
6377 end if;
6379 -- Generate warning for expressions like -5 mod 3
6381 if Paren_Count (N) = 0
6382 and then Nkind (N) = N_Op_Minus
6383 and then Nkind (Right_Opnd (N)) = N_Op_Mod
6384 and then Comes_From_Source (N)
6385 then
6386 Error_Msg_N
6388 end if;
6390 if Comes_From_Source (N)
6391 and then Ekind (Entity (N)) = E_Function
6392 and then Is_Imported (Entity (N))
6393 and then Is_Intrinsic_Subprogram (Entity (N))
6394 then
6395 Resolve_Intrinsic_Unary_Operator (N, Typ);
6396 return;
6397 end if;
6399 if Etype (R) = Universal_Integer
6400 or else Etype (R) = Universal_Real
6401 then
6402 Check_For_Visible_Operator (N, B_Typ);
6403 end if;
6405 Set_Etype (N, B_Typ);
6406 Resolve (R, B_Typ);
6408 Check_Unset_Reference (R);
6409 Generate_Operator_Reference (N, B_Typ);
6410 Eval_Unary_Op (N);
6412 -- Set overflow checking bit. Much cleverer code needed here eventually
6413 -- and perhaps the Resolve routines should be separated for the various
6414 -- arithmetic operations, since they will need different processing ???
6416 if Nkind (N) in N_Op then
6417 if not Overflow_Checks_Suppressed (Etype (N)) then
6418 Enable_Overflow_Check (N);
6419 end if;
6420 end if;
6421 end Resolve_Unary_Op;
6423 ----------------------------------
6424 -- Resolve_Unchecked_Expression --
6425 ----------------------------------
6427 procedure Resolve_Unchecked_Expression
6428 (N : Node_Id;
6429 Typ : Entity_Id)
6430 is
6431 begin
6432 Resolve (Expression (N), Typ, Suppress => All_Checks);
6433 Set_Etype (N, Typ);
6434 end Resolve_Unchecked_Expression;
6436 ---------------------------------------
6437 -- Resolve_Unchecked_Type_Conversion --
6438 ---------------------------------------
6440 procedure Resolve_Unchecked_Type_Conversion
6441 (N : Node_Id;
6442 Typ : Entity_Id)
6443 is
6444 pragma Warnings (Off, Typ);
6446 Operand : constant Node_Id := Expression (N);
6447 Opnd_Type : constant Entity_Id := Etype (Operand);
6449 begin
6450 -- Resolve operand using its own type.
6452 Resolve (Operand, Opnd_Type);
6453 Eval_Unchecked_Conversion (N);
6455 end Resolve_Unchecked_Type_Conversion;
6457 ------------------------------
6458 -- Rewrite_Operator_As_Call --
6459 ------------------------------
6461 procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id) is
6462 Loc : constant Source_Ptr := Sloc (N);
6463 Actuals : constant List_Id := New_List;
6464 New_N : Node_Id;
6466 begin
6467 if Nkind (N) in N_Binary_Op then
6468 Append (Left_Opnd (N), Actuals);
6469 end if;
6471 Append (Right_Opnd (N), Actuals);
6473 New_N :=
6474 Make_Function_Call (Sloc => Loc,
6475 Name => New_Occurrence_Of (Nam, Loc),
6476 Parameter_Associations => Actuals);
6478 Preserve_Comes_From_Source (New_N, N);
6479 Preserve_Comes_From_Source (Name (New_N), N);
6480 Rewrite (N, New_N);
6481 Set_Etype (N, Etype (Nam));
6482 end Rewrite_Operator_As_Call;
6484 ------------------------------
6485 -- Rewrite_Renamed_Operator --
6486 ------------------------------
6488 procedure Rewrite_Renamed_Operator (N : Node_Id; Op : Entity_Id) is
6489 Nam : constant Name_Id := Chars (Op);
6490 Is_Binary : constant Boolean := Nkind (N) in N_Binary_Op;
6491 Op_Node : Node_Id;
6493 begin
6494 -- Rewrite the operator node using the real operator, not its
6495 -- renaming. Exclude user-defined intrinsic operations, which
6496 -- are treated separately.
6498 if Ekind (Op) /= E_Function then
6499 Op_Node := New_Node (Operator_Kind (Nam, Is_Binary), Sloc (N));
6500 Set_Chars (Op_Node, Nam);
6501 Set_Etype (Op_Node, Etype (N));
6502 Set_Entity (Op_Node, Op);
6503 Set_Right_Opnd (Op_Node, Right_Opnd (N));
6505 -- Indicate that both the original entity and its renaming
6506 -- are referenced at this point.
6508 Generate_Reference (Entity (N), N);
6509 Generate_Reference (Op, N);
6511 if Is_Binary then
6512 Set_Left_Opnd (Op_Node, Left_Opnd (N));
6513 end if;
6515 Rewrite (N, Op_Node);
6516 end if;
6517 end Rewrite_Renamed_Operator;
6519 -----------------------
6520 -- Set_Slice_Subtype --
6521 -----------------------
6523 -- Build an implicit subtype declaration to represent the type delivered
6524 -- by the slice. This is an abbreviated version of an array subtype. We
6525 -- define an index subtype for the slice, using either the subtype name
6526 -- or the discrete range of the slice. To be consistent with index usage
6527 -- elsewhere, we create a list header to hold the single index. This list
6528 -- is not otherwise attached to the syntax tree.
6530 procedure Set_Slice_Subtype (N : Node_Id) is
6531 Loc : constant Source_Ptr := Sloc (N);
6532 Index_List : constant List_Id := New_List;
6533 Index : Node_Id;
6534 Index_Subtype : Entity_Id;
6535 Index_Type : Entity_Id;
6536 Slice_Subtype : Entity_Id;
6537 Drange : constant Node_Id := Discrete_Range (N);
6539 begin
6540 if Is_Entity_Name (Drange) then
6541 Index_Subtype := Entity (Drange);
6543 else
6544 -- We force the evaluation of a range. This is definitely needed in
6545 -- the renamed case, and seems safer to do unconditionally. Note in
6546 -- any case that since we will create and insert an Itype referring
6547 -- to this range, we must make sure any side effect removal actions
6548 -- are inserted before the Itype definition.
6550 if Nkind (Drange) = N_Range then
6551 Force_Evaluation (Low_Bound (Drange));
6552 Force_Evaluation (High_Bound (Drange));
6553 end if;
6555 Index_Type := Base_Type (Etype (Drange));
6557 Index_Subtype := Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
6559 Set_Scalar_Range (Index_Subtype, Drange);
6560 Set_Etype (Index_Subtype, Index_Type);
6561 Set_Size_Info (Index_Subtype, Index_Type);
6562 Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
6563 end if;
6565 Slice_Subtype := Create_Itype (E_Array_Subtype, N);
6567 Index := New_Occurrence_Of (Index_Subtype, Loc);
6568 Set_Etype (Index, Index_Subtype);
6569 Append (Index, Index_List);
6571 Set_First_Index (Slice_Subtype, Index);
6572 Set_Etype (Slice_Subtype, Base_Type (Etype (N)));
6573 Set_Is_Constrained (Slice_Subtype, True);
6574 Init_Size_Align (Slice_Subtype);
6576 Check_Compile_Time_Size (Slice_Subtype);
6578 -- The Etype of the existing Slice node is reset to this slice
6579 -- subtype. Its bounds are obtained from its first index.
6581 Set_Etype (N, Slice_Subtype);
6583 -- In the packed case, this must be immediately frozen
6585 -- Couldn't we always freeze here??? and if we did, then the above
6586 -- call to Check_Compile_Time_Size could be eliminated, which would
6587 -- be nice, because then that routine could be made private to Freeze.
6589 if Is_Packed (Slice_Subtype) and not In_Default_Expression then
6590 Freeze_Itype (Slice_Subtype, N);
6591 end if;
6593 end Set_Slice_Subtype;
6595 --------------------------------
6596 -- Set_String_Literal_Subtype --
6597 --------------------------------
6599 procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id) is
6600 Subtype_Id : Entity_Id;
6602 begin
6603 if Nkind (N) /= N_String_Literal then
6604 return;
6605 else
6606 Subtype_Id := Create_Itype (E_String_Literal_Subtype, N);
6607 end if;
6609 Set_String_Literal_Length (Subtype_Id, UI_From_Int
6610 (String_Length (Strval (N))));
6611 Set_Etype (Subtype_Id, Base_Type (Typ));
6612 Set_Is_Constrained (Subtype_Id);
6614 -- The low bound is set from the low bound of the corresponding
6615 -- index type. Note that we do not store the high bound in the
6616 -- string literal subtype, but it can be deduced if necssary
6617 -- from the length and the low bound.
6619 Set_String_Literal_Low_Bound
6620 (Subtype_Id, Type_Low_Bound (Etype (First_Index (Typ))));
6622 Set_Etype (N, Subtype_Id);
6623 end Set_String_Literal_Subtype;
6625 -----------------------------
6626 -- Unique_Fixed_Point_Type --
6627 -----------------------------
6629 function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id is
6630 T1 : Entity_Id := Empty;
6631 T2 : Entity_Id;
6632 Item : Node_Id;
6633 Scop : Entity_Id;
6635 procedure Fixed_Point_Error;
6636 -- If true ambiguity, give details.
6638 procedure Fixed_Point_Error is
6639 begin
6643 end Fixed_Point_Error;
6645 begin
6646 -- The operations on Duration are visible, so Duration is always a
6647 -- possible interpretation.
6649 T1 := Standard_Duration;
6651 -- Look for fixed-point types in enclosing scopes.
6653 Scop := Current_Scope;
6654 while Scop /= Standard_Standard loop
6655 T2 := First_Entity (Scop);
6657 while Present (T2) loop
6658 if Is_Fixed_Point_Type (T2)
6659 and then Current_Entity (T2) = T2
6660 and then Scope (Base_Type (T2)) = Scop
6661 then
6662 if Present (T1) then
6663 Fixed_Point_Error;
6664 return Any_Type;
6665 else
6666 T1 := T2;
6667 end if;
6668 end if;
6670 Next_Entity (T2);
6671 end loop;
6673 Scop := Scope (Scop);
6674 end loop;
6676 -- Look for visible fixed type declarations in the context.
6678 Item := First (Context_Items (Cunit (Current_Sem_Unit)));
6680 while Present (Item) loop
6681 if Nkind (Item) = N_With_Clause then
6682 Scop := Entity (Name (Item));
6683 T2 := First_Entity (Scop);
6685 while Present (T2) loop
6686 if Is_Fixed_Point_Type (T2)
6687 and then Scope (Base_Type (T2)) = Scop
6688 and then (Is_Potentially_Use_Visible (T2)
6689 or else In_Use (T2))
6690 then
6691 if Present (T1) then
6692 Fixed_Point_Error;
6693 return Any_Type;
6694 else
6695 T1 := T2;
6696 end if;
6697 end if;
6699 Next_Entity (T2);
6700 end loop;
6701 end if;
6703 Next (Item);
6704 end loop;
6706 if Nkind (N) = N_Real_Literal then
6709 else
6711 end if;
6713 return T1;
6714 end Unique_Fixed_Point_Type;
6716 ----------------------
6717 -- Valid_Conversion --
6718 ----------------------
6720 function Valid_Conversion
6721 (N : Node_Id;
6722 Target : Entity_Id;
6723 Operand : Node_Id)
6724 return Boolean
6725 is
6726 Target_Type : constant Entity_Id := Base_Type (Target);
6727 Opnd_Type : Entity_Id := Etype (Operand);
6729 function Conversion_Check
6730 (Valid : Boolean;
6731 Msg : String)
6732 return Boolean;
6733 -- Little routine to post Msg if Valid is False, returns Valid value
6735 function Valid_Tagged_Conversion
6736 (Target_Type : Entity_Id;
6737 Opnd_Type : Entity_Id)
6738 return Boolean;
6739 -- Specifically test for validity of tagged conversions
6741 ----------------------
6742 -- Conversion_Check --
6743 ----------------------
6745 function Conversion_Check
6746 (Valid : Boolean;
6747 Msg : String)
6748 return Boolean
6749 is
6750 begin
6751 if not Valid then
6752 Error_Msg_N (Msg, Operand);
6753 end if;
6755 return Valid;
6756 end Conversion_Check;
6758 -----------------------------
6759 -- Valid_Tagged_Conversion --
6760 -----------------------------
6762 function Valid_Tagged_Conversion
6763 (Target_Type : Entity_Id;
6764 Opnd_Type : Entity_Id)
6765 return Boolean
6766 is
6767 begin
6768 -- Upward conversions are allowed (RM 4.6(22)).
6770 if Covers (Target_Type, Opnd_Type)
6771 or else Is_Ancestor (Target_Type, Opnd_Type)
6772 then
6773 return True;
6775 -- Downward conversion are allowed if the operand is
6776 -- is class-wide (RM 4.6(23)).
6778 elsif Is_Class_Wide_Type (Opnd_Type)
6779 and then Covers (Opnd_Type, Target_Type)
6780 then
6781 return True;
6783 elsif Covers (Opnd_Type, Target_Type)
6784 or else Is_Ancestor (Opnd_Type, Target_Type)
6785 then
6786 return
6787 Conversion_Check (False,
6789 else
6790 Error_Msg_NE
6792 N, First_Subtype (Opnd_Type));
6793 return False;
6794 end if;
6795 end Valid_Tagged_Conversion;
6797 -- Start of processing for Valid_Conversion
6799 begin
6800 Check_Parameterless_Call (Operand);
6802 if Is_Overloaded (Operand) then
6803 declare
6804 I : Interp_Index;
6805 I1 : Interp_Index;
6806 It : Interp;
6807 It1 : Interp;
6808 N1 : Entity_Id;
6810 begin
6811 -- Remove procedure calls, which syntactically cannot appear
6812 -- in this context, but which cannot be removed by type checking,
6813 -- because the context does not impose a type.
6815 Get_First_Interp (Operand, I, It);
6817 while Present (It.Typ) loop
6819 if It.Typ = Standard_Void_Type then
6820 Remove_Interp (I);
6821 end if;
6823 Get_Next_Interp (I, It);
6824 end loop;
6826 Get_First_Interp (Operand, I, It);
6827 I1 := I;
6828 It1 := It;
6830 if No (It.Typ) then
6832 return False;
6833 end if;
6835 Get_Next_Interp (I, It);
6837 if Present (It.Typ) then
6838 N1 := It1.Nam;
6839 It1 := Disambiguate (Operand, I1, I, Any_Type);
6841 if It1 = No_Interp then
6844 Error_Msg_Sloc := Sloc (It.Nam);
6847 Error_Msg_Sloc := Sloc (N1);
6850 return False;
6851 end if;
6852 end if;
6854 Set_Etype (Operand, It1.Typ);
6855 Opnd_Type := It1.Typ;
6856 end;
6857 end if;
6859 if Chars (Current_Scope) = Name_Unchecked_Conversion then
6861 -- This check is dubious, what if there were a user defined
6862 -- scope whose name was Unchecked_Conversion ???
6864 return True;
6866 elsif Is_Numeric_Type (Target_Type) then
6867 if Opnd_Type = Universal_Fixed then
6868 return True;
6869 else
6870 return Conversion_Check (Is_Numeric_Type (Opnd_Type),
6872 end if;
6874 elsif Is_Array_Type (Target_Type) then
6875 if not Is_Array_Type (Opnd_Type)
6876 or else Opnd_Type = Any_Composite
6877 or else Opnd_Type = Any_String
6878 then
6879 Error_Msg_N
6881 return False;
6883 elsif Number_Dimensions (Target_Type) /=
6884 Number_Dimensions (Opnd_Type)
6885 then
6886 Error_Msg_N
6888 return False;
6890 else
6891 declare
6892 Target_Index : Node_Id := First_Index (Target_Type);
6893 Opnd_Index : Node_Id := First_Index (Opnd_Type);
6895 Target_Index_Type : Entity_Id;
6896 Opnd_Index_Type : Entity_Id;
6898 Target_Comp_Type : constant Entity_Id :=
6899 Component_Type (Target_Type);
6900 Opnd_Comp_Type : constant Entity_Id :=
6901 Component_Type (Opnd_Type);
6903 begin
6904 while Present (Target_Index) and then Present (Opnd_Index) loop
6905 Target_Index_Type := Etype (Target_Index);
6906 Opnd_Index_Type := Etype (Opnd_Index);
6908 if not (Is_Integer_Type (Target_Index_Type)
6909 and then Is_Integer_Type (Opnd_Index_Type))
6910 and then (Root_Type (Target_Index_Type)
6911 /= Root_Type (Opnd_Index_Type))
6912 then
6913 Error_Msg_N
6915 Operand);
6916 return False;
6917 end if;
6919 Next_Index (Target_Index);
6920 Next_Index (Opnd_Index);
6921 end loop;
6923 if Base_Type (Target_Comp_Type) /=
6924 Base_Type (Opnd_Comp_Type)
6925 then
6926 Error_Msg_N
6928 Operand);
6929 return False;
6931 elsif
6932 Is_Constrained (Target_Comp_Type)
6933 /= Is_Constrained (Opnd_Comp_Type)
6934 or else not Subtypes_Statically_Match
6935 (Target_Comp_Type, Opnd_Comp_Type)
6936 then
6937 Error_Msg_N
6939 return False;
6941 end if;
6942 end;
6943 end if;
6945 return True;
6947 elsif (Ekind (Target_Type) = E_General_Access_Type
6948 or else Ekind (Target_Type) = E_Anonymous_Access_Type)
6949 and then
6950 Conversion_Check
6951 (Is_Access_Type (Opnd_Type)
6952 and then Ekind (Opnd_Type) /=
6953 E_Access_Subprogram_Type
6954 and then Ekind (Opnd_Type) /=
6955 E_Access_Protected_Subprogram_Type,
6957 then
6958 if Is_Access_Constant (Opnd_Type)
6959 and then not Is_Access_Constant (Target_Type)
6960 then
6961 Error_Msg_N
6963 return False;
6964 end if;
6966 -- Check the static accessibility rule of 4.6(17). Note that
6967 -- the check is not enforced when within an instance body, since
6968 -- the RM requires such cases to be caught at run time.
6970 if Ekind (Target_Type) /= E_Anonymous_Access_Type then
6971 if Type_Access_Level (Opnd_Type)
6972 > Type_Access_Level (Target_Type)
6973 then
6974 -- In an instance, this is a run-time check, but one we
6975 -- know will fail, so generate an appropriate warning.
6976 -- The raise will be generated by Expand_N_Type_Conversion.
6978 if In_Instance_Body then
6979 Error_Msg_N
6981 Operand);
6982 Error_Msg_N
6985 else
6986 Error_Msg_N
6988 Operand);
6989 return False;
6990 end if;
6992 elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type then
6994 -- When the operand is a selected access discriminant
6995 -- the check needs to be made against the level of the
6996 -- object denoted by the prefix of the selected name.
6997 -- (Object_Access_Level handles checking the prefix
6998 -- of the operand for this case.)
7000 if Nkind (Operand) = N_Selected_Component
7001 and then Object_Access_Level (Operand)
7002 > Type_Access_Level (Target_Type)
7003 then
7004 -- In an instance, this is a run-time check, but one we
7005 -- know will fail, so generate an appropriate warning.
7006 -- The raise will be generated by Expand_N_Type_Conversion.
7008 if In_Instance_Body then
7009 Error_Msg_N
7012 Error_Msg_N
7015 else
7016 Error_Msg_N
7019 return False;
7020 end if;
7021 end if;
7023 -- The case of a reference to an access discriminant
7024 -- from within a type declaration (which will appear
7025 -- as a discriminal) is always illegal because the
7026 -- level of the discriminant is considered to be
7027 -- deeper than any (namable) access type.
7029 if Is_Entity_Name (Operand)
7030 and then (Ekind (Entity (Operand)) = E_In_Parameter
7031 or else Ekind (Entity (Operand)) = E_Constant)
7032 and then Present (Discriminal_Link (Entity (Operand)))
7033 then
7034 Error_Msg_N
7036 Operand);
7037 return False;
7038 end if;
7039 end if;
7040 end if;
7042 declare
7043 Target : constant Entity_Id := Designated_Type (Target_Type);
7044 Opnd : constant Entity_Id := Designated_Type (Opnd_Type);
7046 begin
7047 if Is_Tagged_Type (Target) then
7048 return Valid_Tagged_Conversion (Target, Opnd);
7050 else
7051 if Base_Type (Target) /= Base_Type (Opnd) then
7052 Error_Msg_NE
7054 N, Base_Type (Opnd));
7055 return False;
7057 elsif not Subtypes_Statically_Match (Target, Opnd)
7058 and then (not Has_Discriminants (Target)
7059 or else Is_Constrained (Target))
7060 then
7061 Error_Msg_NE
7063 N, Opnd);
7064 return False;
7066 else
7067 return True;
7068 end if;
7069 end if;
7070 end;
7072 elsif Ekind (Target_Type) = E_Access_Subprogram_Type
7073 and then Conversion_Check
7074 (Ekind (Base_Type (Opnd_Type)) = E_Access_Subprogram_Type,
7076 then
7077 -- Check that the designated types are subtype conformant
7079 if not Subtype_Conformant (Designated_Type (Opnd_Type),
7080 Designated_Type (Target_Type))
7081 then
7082 Error_Msg_N
7084 Operand);
7085 end if;
7087 -- Check the static accessibility rule of 4.6(20)
7089 if Type_Access_Level (Opnd_Type) >
7090 Type_Access_Level (Target_Type)
7091 then
7092 Error_Msg_N
7094 Operand);
7096 -- Check that if the operand type is declared in a generic body,
7097 -- then the target type must be declared within that same body
7098 -- (enforces last sentence of 4.6(20)).
7100 elsif Present (Enclosing_Generic_Body (Opnd_Type)) then
7101 declare
7102 O_Gen : constant Node_Id :=
7103 Enclosing_Generic_Body (Opnd_Type);
7105 T_Gen : Node_Id :=
7106 Enclosing_Generic_Body (Target_Type);
7108 begin
7109 while Present (T_Gen) and then T_Gen /= O_Gen loop
7110 T_Gen := Enclosing_Generic_Body (T_Gen);
7111 end loop;
7113 if T_Gen /= O_Gen then
7114 Error_Msg_N
7117 end if;
7118 end;
7119 end if;
7121 return True;
7123 elsif Is_Remote_Access_To_Subprogram_Type (Target_Type)
7124 and then Is_Remote_Access_To_Subprogram_Type (Opnd_Type)
7125 then
7126 -- It is valid to convert from one RAS type to another provided
7127 -- that their specification statically match.
7129 Check_Subtype_Conformant
7130 (New_Id =>
7131 Designated_Type (Corresponding_Remote_Type (Target_Type)),
7132 Old_Id =>
7133 Designated_Type (Corresponding_Remote_Type (Opnd_Type)),
7134 Err_Loc =>
7135 N);
7136 return True;
7138 elsif Is_Tagged_Type (Target_Type) then
7139 return Valid_Tagged_Conversion (Target_Type, Opnd_Type);
7141 -- Types derived from the same root type are convertible.
7143 elsif Root_Type (Target_Type) = Root_Type (Opnd_Type) then
7144 return True;
7146 -- In an instance, there may be inconsistent views of the same
7147 -- type, or types derived from the same type.
7149 elsif In_Instance
7150 and then Underlying_Type (Target_Type) = Underlying_Type (Opnd_Type)
7151 then
7152 return True;
7154 -- Special check for common access type error case
7156 elsif Ekind (Target_Type) = E_Access_Type
7157 and then Is_Access_Type (Opnd_Type)
7158 then
7162 return False;
7164 else
7166 N, Opnd_Type);
7168 return False;
7169 end if;
7170 end Valid_Conversion;
7172 end Sem_Res;