| blob | c6a5a5ace599840533a8c1a9936b1befa50ebe26 |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
81 -----------------------
82 -- Local Subprograms --
83 -----------------------
85 -- Second pass (top-down) type checking and overload resolution procedures
86 -- Typ is the type required by context. These procedures propagate the
87 -- type information recursively to the descendants of N. If the node
88 -- is not overloaded, its Etype is established in the first pass. If
89 -- overloaded, the Resolve routines set the correct type. For arith.
90 -- operators, the Etype is the base type of the context.
92 -- Note that Resolve_Attribute is separated off in Sem_Attr
95 -- Enforce the restrictions on the use of discriminants when constraining
96 -- a component of a discriminated type (record or concurrent type).
99 -- Given a node for an operator associated with type T, check that
100 -- the operator is visible. Operators all of whose operands are
101 -- universal must be checked for visibility during resolution
102 -- because their type is not determinable based on their operands.
104 procedure Check_Fully_Declared_Prefix
107 -- Check that the type of the prefix of a dereference is not incomplete
110 -- Given a call node, N, which is known to occur immediately within the
111 -- subprogram being called, determines whether it is a detectable case of
112 -- an infinite recursion, and if so, outputs appropriate messages. Returns
113 -- True if an infinite recursion is detected, and False otherwise.
116 -- If the type of the object being initialized uses the secondary stack
117 -- directly or indirectly, create a transient scope for the call to the
118 -- init proc. This is because we do not create transient scopes for the
119 -- initialization of individual components within the init proc itself.
120 -- Could be optimized away perhaps?
123 -- N is the node for a logical operator. If the operator is predefined, and
124 -- the root type of the operands is Standard.Boolean, then a check is made
125 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
126 -- the style check for Style_Check_Boolean_And_Or.
129 -- Determine whether E is an access type declared by an access
130 -- declaration, and not an (anonymous) allocator type.
133 -- Utility to check whether the name in the call is a predefined
134 -- operator, in which case the call is made into an operator node.
135 -- An instance of an intrinsic conversion operation may be given
136 -- an operator name, but is not treated like an operator.
139 -- If a default expression in entry call N depends on the discriminants
140 -- of the task, it must be replaced with a reference to the discriminant
141 -- of the task being called.
143 procedure Resolve_Op_Concat_Arg
148 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
149 -- concatenation operator. The operand is either of the array type or of
150 -- the component type. If the operand is an aggregate, and the component
151 -- type is composite, this is ambiguous if component type has aggregates.
154 -- Does the first part of the work of Resolve_Op_Concat
157 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
158 -- has been resolved. See Resolve_Op_Concat for details.
193 function Operator_Kind
196 -- Utility to map the name of an operator into the corresponding Node. Used
197 -- by other node rewriting procedures.
200 -- Resolve actuals of call, and add default expressions for missing ones.
201 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
202 -- called subprogram.
205 -- Called from Resolve_Call, when the prefix denotes an entry or element
206 -- of entry family. Actuals are resolved as for subprograms, and the node
207 -- is rebuilt as an entry call. Also called for protected operations. Typ
208 -- is the context type, which is used when the operation is a protected
209 -- function with no arguments, and the return value is indexed.
212 -- A call to a user-defined intrinsic operator is rewritten as a call
213 -- to the corresponding predefined operator, with suitable conversions.
216 -- Ditto, for unary operators (only arithmetic ones)
219 -- If an operator node resolves to a call to a user-defined operator,
220 -- rewrite the node as a function call.
222 procedure Make_Call_Into_Operator
226 -- Inverse transformation: if an operator is given in functional notation,
227 -- then after resolving the node, transform into an operator node, so
228 -- that operands are resolved properly. Recall that predefined operators
229 -- do not have a full signature and special resolution rules apply.
231 procedure Rewrite_Renamed_Operator
235 -- An operator can rename another, e.g. in an instantiation. In that
236 -- case, the proper operator node must be constructed and resolved.
239 -- The String_Literal_Subtype is built for all strings that are not
240 -- operands of a static concatenation operation. If the argument is
241 -- not a N_String_Literal node, then the call has no effect.
244 -- Build subtype of array type, with the range specified by the slice
247 -- Called after N has been resolved and evaluated, but before range checks
248 -- have been applied. Currently simplifies a combination of floating-point
249 -- to integer conversion and Truncation attribute.
252 -- A universal_fixed expression in an universal context is unambiguous
253 -- if there is only one applicable fixed point type. Determining whether
254 -- there is only one requires a search over all visible entities, and
255 -- happens only in very pathological cases (see 6115-006).
257 function Valid_Conversion
261 -- Verify legality rules given in 4.6 (8-23). Target is the target
262 -- type of the conversion, which may be an implicit conversion of
263 -- an actual parameter to an anonymous access type (in which case
264 -- N denotes the actual parameter and N = Operand).
266 -------------------------
267 -- Ambiguous_Character --
268 -------------------------
273 begin
277 -- First the ones in Standard
279 Error_Msg_N
281 Error_Msg_N
284 -- Include Wide_Wide_Character in Ada 2005 mode
287 Error_Msg_N
291 -- Now any other types that match
301 -------------------------
302 -- Analyze_And_Resolve --
303 -------------------------
306 begin
312 begin
317 -- Version withs check(s) suppressed
319 procedure Analyze_And_Resolve
323 is
326 begin
328 declare
330 begin
336 else
337 declare
340 begin
348 and then Scope_Is_Transient
349 then
350 -- This can only happen if a transient scope was created
351 -- for an inner expression, which will be removed upon
352 -- completion of the analysis of an enclosing construct.
353 -- The transient scope must have the suppress status of
354 -- the enclosing environment, not of this Analyze call.
357 Scope_Suppress;
361 procedure Analyze_And_Resolve
364 is
367 begin
369 declare
371 begin
377 else
378 declare
381 begin
389 and then Scope_Is_Transient
390 then
392 Scope_Suppress;
396 ----------------------------
397 -- Check_Discriminant_Use --
398 ----------------------------
406 begin
407 -- Any use in a spec-expression is legal
414 -- Discriminant cannot be used to constrain a scalar type
421 then
426 -- The following check catches the unusual case where
427 -- a discriminant appears within an index constraint
428 -- that is part of a larger expression within a constraint
429 -- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
430 -- For now we only check case of record components, and
431 -- note that a similar check should also apply in the
432 -- case of discriminant constraints below. ???
434 -- Note that the check for N_Subtype_Declaration below is to
435 -- detect the valid use of discriminants in the constraints of a
436 -- subtype declaration when this subtype declaration appears
437 -- inside the scope of a record type (which is syntactically
438 -- illegal, but which may be created as part of derived type
439 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
440 -- for more info.
444 and then not
446 and then
448 N_Subtype_Declaration)
450 then
451 Error_Msg_N
456 -- Detect a common error:
458 -- type R (D : Positive := 100) is record
459 -- Name : String (1 .. D);
460 -- end record;
462 -- The default value causes an object of type R to be allocated
463 -- with room for Positive'Last characters. The RM does not mandate
464 -- the allocation of the maximum size, but that is what GNAT does
465 -- so we should warn the programmer that there is a problem.
474 -- Return True if type T has a large enough range that
475 -- any array whose index type covered the whole range of
476 -- the type would likely raise Storage_Error.
478 ------------------------
479 -- Large_Storage_Type --
480 ------------------------
483 begin
484 -- The type is considered large if its bounds are known at
485 -- compile time and if it requires at least as many bits as
486 -- a Positive to store the possible values.
490 and then
495 -- Start of processing for Check_Large
497 begin
498 -- Check that the Disc has a large range
504 -- If the enclosing type is limited, we allocate only the
505 -- default value, not the maximum, and there is no need for
506 -- a warning.
512 -- Check that it is the high bound
516 then
520 -- Check the array allows a large range at this bound.
521 -- First find the array
535 -- Next, find the dimension
543 loop
552 -- Now, check the dimension has a large range
558 -- Warn about the danger
560 Error_Msg_N
570 -- Legal case is in index or discriminant constraint
573 N_Discriminant_Association)
574 then
576 Error_Msg_N
581 then
582 Error_Msg_N
588 -- Otherwise, context is an expression. It should not be within
589 -- (i.e. a subexpression of) a constraint for a component.
591 else
595 N_Subtype_Indication,
596 N_Entry_Declaration)
597 loop
603 -- If the discriminant is used in an expression that is a bound
604 -- of a scalar type, an Itype is created and the bounds are attached
605 -- to its range, not to the original subtype indication. Such use
606 -- is of course a double fault.
610 N_Derived_Type_Definition)
613 -- The constraint itself may be given by a subtype indication,
614 -- rather than by a more common discrete range.
617 and then
621 then
622 Error_Msg_N
628 --------------------------------
629 -- Check_For_Visible_Operator --
630 --------------------------------
633 begin
635 Error_Msg_NE
641 ----------------------------------
642 -- Check_Fully_Declared_Prefix --
643 ----------------------------------
645 procedure Check_Fully_Declared_Prefix
648 is
649 begin
650 -- Check that the designated type of the prefix of a dereference is
651 -- not an incomplete type. This cannot be done unconditionally, because
652 -- dereferences of private types are legal in default expressions. This
653 -- case is taken care of in Check_Fully_Declared, called below. There
654 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
656 -- This consideration also applies to similar checks for allocators,
657 -- qualified expressions, and type conversions.
659 -- An additional exception concerns other per-object expressions that
660 -- are not directly related to component declarations, in particular
661 -- representation pragmas for tasks. These will be per-object
662 -- expressions if they depend on discriminants or some global entity.
663 -- If the task has access discriminants, the designated type may be
664 -- incomplete at the point the expression is resolved. This resolution
665 -- takes place within the body of the initialization procedure, where
666 -- the discriminant is replaced by its discriminal.
670 then
673 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
674 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
675 -- Analyze_Object_Renaming, and Freeze_Entity.
681 E_Incomplete_Type
683 then
685 else
690 ------------------------------
691 -- Check_Infinite_Recursion --
692 ------------------------------
699 -- Check whether list of actuals is identical to list of formals
700 -- of called function (which is also the enclosing scope).
702 ------------------------
703 -- Same_Argument_List --
704 ------------------------
711 begin
714 else
723 then
734 -- Start of processing for Check_Infinite_Recursion
736 begin
737 -- Special case, if this is a procedure call and is a call to the
738 -- current procedure with the same argument list, then this is for
739 -- sure an infinite recursion and we insert a call to raise SE.
743 and then Same_Argument_List
744 then
745 declare
747 begin
751 then
762 -- If not that special case, search up tree, quitting if we reach a
763 -- construct (e.g. a conditional) that tells us that this is not a
764 -- case for an infinite recursion warning.
767 loop
770 -- If no parent, then we were not inside a subprogram, this can for
771 -- example happen when processing certain pragmas in a spec. Just
772 -- return False in this case.
778 -- Done if we get to subprogram body, this is definitely an infinite
779 -- recursion case if we did not find anything to stop us.
783 -- If appearing in conditional, result is false
786 N_And_Then,
787 N_If_Statement,
788 N_Case_Statement)
789 then
794 then
795 -- If the call is the expression of a return statement and the
796 -- actuals are identical to the formals, it's worth a warning.
797 -- However, we skip this if there is an immediately preceding
798 -- raise statement, since the call is never executed.
800 -- Furthermore, this corresponds to a common idiom:
802 -- function F (L : Thing) return Boolean is
803 -- begin
804 -- raise Program_Error;
805 -- return F (L);
806 -- end F;
808 -- for generating a stub function
811 and then Same_Argument_List
812 then
815 -- OK, return statement is in a statement list, look for raise
817 declare
820 begin
821 -- Skip past N_Freeze_Entity nodes generated by expansion
826 loop
830 -- If no raise statement, give warning
833 and then
841 else
852 -------------------------------
853 -- Check_Initialization_Call --
854 -------------------------------
860 -- Check whether the creation of an object of the type will involve
861 -- use of the secondary stack. If T is a record type, this is true
862 -- if the expression for some component uses the secondary stack, e.g.
863 -- through a call to a function that returns an unconstrained value.
864 -- False if T is controlled, because cleanups occur elsewhere.
866 -------------
867 -- Uses_SS --
868 -------------
875 begin
876 -- Normally we want to use the underlying type, but if it's not set
877 -- then continue with T.
894 then
895 -- The expression for a dynamic component may be rewritten
896 -- as a dereference, so retrieve original node.
900 -- Return True if the expression is a call to a function
901 -- (including an attribute function such as Image) with
902 -- a result that requires a transient scope.
908 then
921 else
926 -- Start of processing for Check_Initialization_Call
928 begin
929 -- Establish a transient scope if the type needs it
936 ---------------------------------------
937 -- Check_No_Direct_Boolean_Operators --
938 ---------------------------------------
941 begin
944 then
945 -- Restriction only applies to original source code
957 ------------------------------
958 -- Check_Parameterless_Call --
959 ------------------------------
965 -- If the prefix is of an access_to_subprogram type, the node must be
966 -- rewritten as a call. Ditto if the prefix is overloaded and all its
967 -- interpretations are access to subprograms.
969 ---------------------------
970 -- Prefix_Is_Access_Subp --
971 ---------------------------
977 begin
979 return
982 else
987 then
998 -- Start of processing for Check_Parameterless_Call
1000 begin
1001 -- Defend against junk stuff if errors already detected
1008 then
1015 -- If the context expects a value, and the name is a procedure, this is
1016 -- most likely a missing 'Access. Don't try to resolve the parameterless
1017 -- call, error will be caught when the outer call is analyzed.
1022 and then
1024 N_Function_Call,
1025 N_Procedure_Call_Statement)
1026 then
1030 -- Rewrite as call if overloadable entity that is (or could be, in the
1031 -- overloaded case) a function call. If we know for sure that the entity
1032 -- is an enumeration literal, we do not rewrite it.
1039 -- Rewrite as call if it is an explicit dereference of an expression of
1040 -- a subprogram access type, and the subprogram type is not that of a
1041 -- procedure or entry.
1043 or else
1046 -- Rewrite as call if it is a selected component which is a function,
1047 -- this is the case of a call to a protected function (which may be
1048 -- overloaded with other protected operations).
1050 or else
1053 or else
1055 or else
1059 -- If one of the above three conditions is met, rewrite as call.
1060 -- Apply the rewriting only once.
1062 then
1065 then
1068 -- If overloaded, overload set belongs to new copy
1072 -- Change node to parameterless function call (note that the
1073 -- Parameter_Associations associations field is left set to Empty,
1074 -- its normal default value since there are no parameters)
1087 -----------------------------
1088 -- Is_Definite_Access_Type --
1089 -----------------------------
1093 begin
1099 ----------------------
1100 -- Is_Predefined_Op --
1101 ----------------------
1104 begin
1112 -----------------------------
1113 -- Make_Call_Into_Operator --
1114 -----------------------------
1116 procedure Make_Call_Into_Operator
1120 is
1135 -- If the operand is not universal, and the operator is given by a
1136 -- expanded name, verify that the operand has an interpretation with
1137 -- a type defined in the given scope of the operator.
1140 -- Find a type of the given class in the package Pack that contains
1141 -- the operator.
1143 ---------------------------
1144 -- Operand_Type_In_Scope --
1145 ---------------------------
1152 begin
1156 else
1170 ---------------
1171 -- Type_In_P --
1172 ---------------
1178 -- Verify that node is not part of the type declaration for the
1179 -- candidate type, which would otherwise be invisible.
1181 -------------
1182 -- In_Decl --
1183 -------------
1189 begin
1198 else
1201 loop
1204 else
1213 -- Start of processing for Type_In_P
1215 begin
1216 -- If the context type is declared in the prefix package, this
1217 -- is the desired base type.
1221 then
1224 else
1228 and then not In_Decl
1229 then
1240 -- Start of processing for Make_Call_Into_Operator
1242 begin
1245 -- Binary operator
1255 -- Unary operator
1257 else
1263 -- If the operator is denoted by an expanded name, and the prefix is
1264 -- not Standard, but the operator is a predefined one whose scope is
1265 -- Standard, then this is an implicit_operator, inserted as an
1266 -- interpretation by the procedure of the same name. This procedure
1267 -- overestimates the presence of implicit operators, because it does
1268 -- not examine the type of the operands. Verify now that the operand
1269 -- type appears in the given scope. If right operand is universal,
1270 -- check the other operand. In the case of concatenation, either
1271 -- argument can be the component type, so check the type of the result.
1272 -- If both arguments are literals, look for a type of the right kind
1273 -- defined in the given scope. This elaborate nonsense is brought to
1274 -- you courtesy of b33302a. The type itself must be frozen, so we must
1275 -- find the type of the proper class in the given scope.
1277 -- A final wrinkle is the multiplication operator for fixed point
1278 -- types, which is defined in Standard only, and not in the scope of
1279 -- the fixed_point type itself.
1284 -- If the entity being called is defined in the given package,
1285 -- it is a renaming of a predefined operator, and known to be
1286 -- legal.
1290 then
1293 -- Visibility does not need to be checked in an instance: if the
1294 -- operator was not visible in the generic it has been diagnosed
1295 -- already, else there is an implicit copy of it in the instance.
1304 then
1309 -- Ada 2005, AI-420: Predefined equality on Universal_Access
1310 -- is available.
1315 then
1318 else
1327 and then Is_Binary
1329 then
1335 -- Verify that the scope contains a type that corresponds to
1336 -- the given literal. Optimize the case where Pack is Standard.
1358 else
1367 else
1376 then
1379 -- If the type is defined elsewhere, and the operator is not
1380 -- defined in the given scope (by a renaming declaration, e.g.)
1381 -- then this is an error as well. If an extension of System is
1382 -- present, and the type may be defined there, Pack must be
1383 -- System itself.
1390 then
1393 else
1399 then
1406 Error_Msg_NE
1417 else
1421 -- If this is a call to a function that renames a predefined equality,
1422 -- the renaming declaration provides a type that must be used to
1423 -- resolve the operands. This must be done now because resolution of
1424 -- the equality node will not resolve any remaining ambiguity, and it
1425 -- assumes that the first operand is not overloaded.
1430 then
1438 -- Do rewrite setting Comes_From_Source on the result if the original
1439 -- call came from source. Although it is not strictly the case that the
1440 -- operator as such comes from the source, logically it corresponds
1441 -- exactly to the function call in the source, so it should be marked
1442 -- this way (e.g. to make sure that validity checks work fine).
1444 declare
1446 begin
1451 -- If this is an arithmetic operator and the result type is private,
1452 -- the operands and the result must be wrapped in conversion to
1453 -- expose the underlying numeric type and expand the proper checks,
1454 -- e.g. on division.
1458 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1459 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1468 else
1472 -- For predefined operators on literals, the operation freezes
1473 -- their type.
1481 -------------------
1482 -- Operator_Kind --
1483 -------------------
1485 function Operator_Kind
1488 is
1491 begin
1527 else
1531 -- Unary operators
1533 else
1542 else
1550 ----------------------------
1551 -- Preanalyze_And_Resolve --
1552 ----------------------------
1557 begin
1561 -- We suppress all checks for this analysis, since the checks will
1562 -- be applied properly, and in the right location, when the default
1563 -- expression is reanalyzed and reexpanded later on.
1567 Expander_Mode_Restore;
1571 -- Version without context type
1576 begin
1583 Expander_Mode_Restore;
1587 ----------------------------------
1588 -- Replace_Actual_Discriminants --
1589 ----------------------------------
1597 -------------------
1598 -- Process_Discr --
1599 -------------------
1604 begin
1610 then
1626 -- Start of processing for Replace_Actual_Discriminants
1628 begin
1642 else
1647 -------------
1648 -- Resolve --
1649 -------------
1665 -- Determine whether a node comes from a predefined library unit or
1666 -- Standard.
1669 -- Try and fix up a literal so that it matches its expected type. New
1670 -- literals are manufactured if necessary to avoid cascaded errors.
1673 -- Called when attempt at resolving current expression fails
1675 ------------------------------------
1676 -- Comes_From_Predefined_Lib_Unit --
1677 -------------------------------------
1680 begin
1681 return
1687 --------------------
1688 -- Patch_Up_Value --
1689 --------------------
1692 begin
1695 then
1704 then
1713 then
1718 Char_Literal_Value =>
1725 then
1736 -----------------------
1737 -- Resolution_Failed --
1738 -----------------------
1741 begin
1747 -- The caller will return without calling the expander, so we need
1748 -- to set the analyzed flag. Note that it is fine to set Analyzed
1749 -- to True even if we are in the middle of a shallow analysis,
1750 -- (see the spec of sem for more details) since this is an error
1751 -- situation anyway, and there is no point in repeating the
1752 -- analysis later (indeed it won't work to repeat it later, since
1753 -- we haven't got a clear resolution of which entity is being
1754 -- referenced.)
1760 -- Start of processing for Resolve
1762 begin
1767 -- Access attribute on remote subprogram cannot be used for
1768 -- a non-remote access-to-subprogram type.
1779 then
1780 Error_Msg_N
1786 -- If the context is a Remote_Access_To_Subprogram, access attributes
1787 -- must be resolved with the corresponding fat pointer. There is no need
1788 -- to check for the attribute name since the return type of an
1789 -- attribute is never a remote type.
1795 then
1796 declare
1804 begin
1805 -- Check that Typ is a remote access-to-subprogram type
1808 -- Prefix (N) must statically denote a remote subprogram
1809 -- declared in a package specification.
1826 or else
1828 then
1830 Error_Msg_N
1832 N);
1836 -- If we are generating code for a distributed program.
1837 -- perform semantic checks against the corresponding
1838 -- remote entities.
1843 and then Expander_Active
1845 then
1846 Check_Subtype_Conformant
1848 Old_Id => Designated_Type
1869 then
1874 -- Return if already analyzed
1880 -- Return if type = Any_Type (previous error encountered)
1889 -- If not overloaded, then we know the type, and all that needs doing
1890 -- is to check that this type is compatible with the context.
1896 -- In the overloaded case, we must select the interpretation that
1897 -- is compatible with the context (i.e. the type passed to Resolve)
1899 else
1900 -- Loop through possible interpretations
1905 -- We are only interested in interpretations that are compatible
1906 -- with the expected type, any other interpretations are ignored.
1911 Write_Eol;
1914 else
1915 -- Skip the current interpretation if it is disabled by an
1916 -- abstract operator. This action is performed only when the
1917 -- type against which we are resolving is the same as the
1918 -- type of the interpretation.
1925 then
1929 -- First matching interpretation
1937 -- Matching interpretation that is not the first, maybe an
1938 -- error, but there are some cases where preference rules are
1939 -- used to choose between the two possibilities. These and
1940 -- some more obscure cases are handled in Disambiguate.
1942 else
1943 -- If the current statement is part of a predefined library
1944 -- unit, then all interpretations which come from user level
1945 -- packages should not be considered.
1947 if From_Lib
1949 then
1956 -- Disambiguation has succeeded. Skip the remaining
1957 -- interpretations.
1967 else
1968 -- Before we issue an ambiguity complaint, check for
1969 -- the case of a subprogram call where at least one
1970 -- of the arguments is Any_Type, and if so, suppress
1971 -- the message, since it is a cascaded error.
1974 N_Procedure_Call_Statement)
1975 then
1976 declare
1980 begin
1992 Write_Eol;
2005 then
2010 then
2014 -- Not that special case, so issue message using the
2015 -- flag Ambiguous to control printing of the header
2016 -- message only at the start of an ambiguous set.
2021 then
2022 Error_Msg_N
2025 else
2026 Error_Msg_NE -- CODEFIX
2034 Error_Msg_N
2036 else
2037 Error_Msg_N -- CODEFIX
2044 -- By default, the error message refers to the candidate
2045 -- interpretation. But if it is a predefined operator, it
2046 -- is implicitly declared at the declaration of the type
2047 -- of the operand. Recover the sloc of that declaration
2048 -- for the error message.
2054 Standard_Standard
2055 then
2060 then
2068 Standard_Standard
2069 then
2074 then
2078 -- If this is an indirect call, use the subprogram_type
2079 -- in the message, to have a meaningful location.
2080 -- Indicate as well if this is an inherited operation,
2081 -- created by a type declaration.
2086 then
2088 Error_Msg_Sloc :=
2090 else
2097 then
2098 -- Special-case the message for universal_fixed
2099 -- operators, which are not declared with the type
2100 -- of the operand, but appear forever in Standard.
2104 then
2105 Error_Msg_N
2109 else
2110 Error_Msg_N
2114 elsif
2116 then
2117 Error_Msg_N
2119 else
2120 Error_Msg_N -- CODEFIX
2127 -- We have a matching interpretation, Expr_Type is the type
2128 -- from this interpretation, and Seen is the entity.
2130 -- For an operator, just set the entity name. The type will be
2131 -- set by the specific operator resolution routine.
2143 -- For an explicit dereference, attribute reference, range,
2144 -- short-circuit form (which is not an operator node), or call
2145 -- with a name that is an explicit dereference, there is
2146 -- nothing to be done at this point.
2149 N_Attribute_Reference,
2150 N_And_Then,
2151 N_Indexed_Component,
2152 N_Or_Else,
2153 N_Range,
2154 N_Selected_Component,
2155 N_Slice)
2157 then
2160 -- For procedure or function calls, set the type of the name,
2161 -- and also the entity pointer for the prefix
2166 then
2173 then
2178 -- For all other cases, just set the type of the Name
2180 else
2188 -- Move to next interpretation
2196 -- At this stage Found indicates whether or not an acceptable
2197 -- interpretation exists. If not, then we have an error, except
2198 -- that if the context is Any_Type as a result of some other error,
2199 -- then we suppress the error report.
2204 -- If type we are looking for is Void, then this is the procedure
2205 -- call case, and the error is simply that what we gave is not a
2206 -- procedure name (we think of procedure calls as expressions with
2207 -- types internally, but the user doesn't think of them this way!)
2211 -- Special case message if function used as a procedure
2216 then
2217 Error_Msg_NE
2221 -- Otherwise give general message (not clear what cases this
2222 -- covers, but no harm in providing for them!)
2224 else
2230 -- Otherwise we do have a subexpression with the wrong type
2232 -- Check for the case of an allocator which uses an access type
2233 -- instead of the designated type. This is a common error and we
2234 -- specialize the message, posting an error on the operand of the
2235 -- allocator, complaining that we expected the designated type of
2236 -- the allocator.
2242 then
2246 -- Check for view mismatch on Null in instances, for which the
2247 -- view-swapping mechanism has no identifier.
2253 then
2258 -- Check for an aggregate. Sometimes we can get bogus aggregates
2259 -- from misuse of parentheses, and we are about to complain about
2260 -- the aggregate without even looking inside it.
2262 -- Instead, if we have an aggregate of type Any_Composite, then
2263 -- analyze and resolve the component fields, and then only issue
2264 -- another message if we get no errors doing this (otherwise
2265 -- assume that the errors in the aggregate caused the problem).
2269 then
2270 -- Disable expansion in any case. If there is a type mismatch
2271 -- it may be fatal to try to expand the aggregate. The flag
2272 -- would otherwise be set to false when the error is posted.
2276 declare
2278 -- Check one aggregate, and set Found to True if we have a
2279 -- definite error in any of its elements
2282 -- Check one element of aggregate and set Found to True if
2283 -- we definitely have an error in the element.
2285 ----------------
2286 -- Check_Aggr --
2287 ----------------
2292 begin
2305 -- If this is a default-initialized component, then
2306 -- there is nothing to check. The box will be
2307 -- replaced by the appropriate call during late
2308 -- expansion.
2319 ----------------
2320 -- Check_Elmt --
2321 ----------------
2324 begin
2325 -- If we have a nested aggregate, go inside it (to
2326 -- attempt a naked analyze-resolve of the aggregate
2327 -- can cause undesirable cascaded errors). Do not
2328 -- resolve expression if it needs a type from context,
2329 -- as for integer * fixed expression.
2334 else
2339 then
2349 begin
2354 -- If an error message was issued already, Found got reset
2355 -- to True, so if it is still False, issue the standard
2356 -- Wrong_Type message.
2361 then
2362 declare
2364 begin
2370 -- Protected operation: retrieve operation name
2373 else
2383 declare
2387 begin
2394 Error_Msg_NE
2400 else
2403 else
2409 Resolution_Failed;
2412 -- Test if we have more than one interpretation for the context
2415 Resolution_Failed;
2418 -- Here we have an acceptable interpretation for the context
2420 else
2421 -- Propagate type information and normalize tree for various
2422 -- predefined operations. If the context only imposes a class of
2423 -- types, rather than a specific type, propagate the actual type
2424 -- downward.
2431 then
2434 -- Any_Fixed is legal in a real context only if a specific
2435 -- fixed point type is imposed. If Norman Cohen can be
2436 -- confused by this, it deserves a separate message.
2440 then
2447 -- A user-defined operator is transformed into a function call at
2448 -- this point, so that further processing knows that operators are
2449 -- really operators (i.e. are predefined operators). User-defined
2450 -- operators that are intrinsic are just renamings of the predefined
2451 -- ones, and need not be turned into calls either, but if they rename
2452 -- a different operator, we must transform the node accordingly.
2453 -- Instantiations of Unchecked_Conversion are intrinsic but are
2454 -- treated as functions, even if given an operator designator.
2459 then
2465 and then
2467 N_Subprogram_Renaming_Declaration
2468 then
2471 -- If the node is rewritten, it will be fully resolved in
2472 -- Rewrite_Renamed_Operator.
2482 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2484 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2486 when N_Short_Circuit
2487 => Resolve_Short_Circuit (N, Ctx_Type);
2489 when N_Attribute_Reference
2490 => Resolve_Attribute (N, Ctx_Type);
2492 when N_Character_Literal
2493 => Resolve_Character_Literal (N, Ctx_Type);
2495 when N_Conditional_Expression
2496 => Resolve_Conditional_Expression (N, Ctx_Type);
2498 when N_Expanded_Name
2499 => Resolve_Entity_Name (N, Ctx_Type);
2501 when N_Extension_Aggregate
2502 => Resolve_Extension_Aggregate (N, Ctx_Type);
2504 when N_Explicit_Dereference
2505 => Resolve_Explicit_Dereference (N, Ctx_Type);
2507 when N_Function_Call
2508 => Resolve_Call (N, Ctx_Type);
2510 when N_Identifier
2511 => Resolve_Entity_Name (N, Ctx_Type);
2513 when N_Indexed_Component
2514 => Resolve_Indexed_Component (N, Ctx_Type);
2516 when N_Integer_Literal
2517 => Resolve_Integer_Literal (N, Ctx_Type);
2519 when N_Membership_Test
2520 => Resolve_Membership_Op (N, Ctx_Type);
2522 when N_Null => Resolve_Null (N, Ctx_Type);
2524 when N_Op_And | N_Op_Or | N_Op_Xor
2525 => Resolve_Logical_Op (N, Ctx_Type);
2527 when N_Op_Eq | N_Op_Ne
2528 => Resolve_Equality_Op (N, Ctx_Type);
2530 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2531 => Resolve_Comparison_Op (N, Ctx_Type);
2533 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2535 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2536 N_Op_Divide | N_Op_Mod | N_Op_Rem
2538 => Resolve_Arithmetic_Op (N, Ctx_Type);
2540 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2542 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2544 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2545 => Resolve_Unary_Op (N, Ctx_Type);
2547 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2549 when N_Procedure_Call_Statement
2550 => Resolve_Call (N, Ctx_Type);
2552 when N_Operator_Symbol
2553 => Resolve_Operator_Symbol (N, Ctx_Type);
2555 when N_Qualified_Expression
2556 => Resolve_Qualified_Expression (N, Ctx_Type);
2558 when N_Raise_xxx_Error
2559 => Set_Etype (N, Ctx_Type);
2561 when N_Range => Resolve_Range (N, Ctx_Type);
2563 when N_Real_Literal
2564 => Resolve_Real_Literal (N, Ctx_Type);
2566 when N_Reference => Resolve_Reference (N, Ctx_Type);
2568 when N_Selected_Component
2569 => Resolve_Selected_Component (N, Ctx_Type);
2571 when N_Slice => Resolve_Slice (N, Ctx_Type);
2573 when N_String_Literal
2574 => Resolve_String_Literal (N, Ctx_Type);
2576 when N_Subprogram_Info
2577 => Resolve_Subprogram_Info (N, Ctx_Type);
2579 when N_Type_Conversion
2580 => Resolve_Type_Conversion (N, Ctx_Type);
2582 when N_Unchecked_Expression =>
2583 Resolve_Unchecked_Expression (N, Ctx_Type);
2585 when N_Unchecked_Type_Conversion =>
2586 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2588 end case;
2590 -- If the subexpression was replaced by a non-subexpression, then
2591 -- all we do is to expand it. The only legitimate case we know of
2592 -- is converting procedure call statement to entry call statements,
2593 -- but there may be others, so we are making this test general.
2595 if Nkind (N) not in N_Subexpr then
2596 Debug_A_Exit ("resolving ", N, " (done)");
2597 Expand (N);
2598 return;
2599 end if;
2601 -- The expression is definitely NOT overloaded at this point, so
2602 -- we reset the Is_Overloaded flag to avoid any confusion when
2603 -- reanalyzing the node.
2605 Set_Is_Overloaded (N, False);
2607 -- Freeze expression type, entity if it is a name, and designated
2608 -- type if it is an allocator (RM 13.14(10,11,13)).
2610 -- Now that the resolution of the type of the node is complete,
2611 -- and we did not detect an error, we can expand this node. We
2612 -- skip the expand call if we are in a default expression, see
2613 -- section "Handling of Default Expressions" in Sem spec.
2615 Debug_A_Exit ("resolving ", N, " (done)");
2617 -- We unconditionally freeze the expression, even if we are in
2618 -- default expression mode (the Freeze_Expression routine tests
2619 -- this flag and only freezes static types if it is set).
2621 Freeze_Expression (N);
2623 -- Now we can do the expansion
2625 Expand (N);
2626 end if;
2627 end Resolve;
2629 -------------
2630 -- Resolve --
2631 -------------
2633 -- Version with check(s) suppressed
2635 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2636 begin
2637 if Suppress = All_Checks then
2638 declare
2639 Svg : constant Suppress_Array := Scope_Suppress;
2640 begin
2641 Scope_Suppress := (others => True);
2642 Resolve (N, Typ);
2643 Scope_Suppress := Svg;
2644 end;
2646 else
2647 declare
2648 Svg : constant Boolean := Scope_Suppress (Suppress);
2649 begin
2650 Scope_Suppress (Suppress) := True;
2651 Resolve (N, Typ);
2652 Scope_Suppress (Suppress) := Svg;
2653 end;
2654 end if;
2655 end Resolve;
2657 -------------
2658 -- Resolve --
2659 -------------
2661 -- Version with implicit type
2663 procedure Resolve (N : Node_Id) is
2664 begin
2665 Resolve (N, Etype (N));
2666 end Resolve;
2668 ---------------------
2669 -- Resolve_Actuals --
2670 ---------------------
2672 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2673 Loc : constant Source_Ptr := Sloc (N);
2674 A : Node_Id;
2675 F : Entity_Id;
2676 A_Typ : Entity_Id;
2677 F_Typ : Entity_Id;
2678 Prev : Node_Id := Empty;
2679 Orig_A : Node_Id;
2681 procedure Check_Argument_Order;
2682 -- Performs a check for the case where the actuals are all simple
2683 -- identifiers that correspond to the formal names, but in the wrong
2684 -- order, which is considered suspicious and cause for a warning.
2686 procedure Check_Prefixed_Call;
2687 -- If the original node is an overloaded call in prefix notation,
2689 -- Try_Object_Operation has already verified that there is a valid
2690 -- interpretation, but the form of the actual can only be determined
2691 -- once the primitive operation is identified.
2694 -- If the actual is missing in a call, insert in the actuals list
2695 -- an instance of the default expression. The insertion is always
2696 -- a named association.
2699 -- Check whether T1 and T2, or their full views, are derived from a
2700 -- common type. Used to enforce the restrictions on array conversions
2701 -- of AI95-00246.
2704 -- Predicate to determine whether an actual that is a concatenation
2705 -- will be evaluated statically and does not need a transient scope.
2706 -- This must be determined before the actual is resolved and expanded
2707 -- because if needed the transient scope must be introduced earlier.
2709 --------------------------
2710 -- Check_Argument_Order --
2711 --------------------------
2714 begin
2715 -- Nothing to do if no parameters, or original node is neither a
2716 -- function call nor a procedure call statement (happens in the
2717 -- operator-transformed-to-function call case), or the call does
2718 -- not come from source, or this warning is off.
2720 if not Warn_On_Parameter_Order
2721 or else
2723 or else
2725 N_Function_Call)
2726 or else
2728 then
2732 declare
2735 begin
2736 -- Nothing to do if only one parameter
2742 -- Here if at least two arguments
2744 declare
2750 -- Set True if an out of order case is found
2752 begin
2753 -- Collect identifier names of actuals, fail if any actual is
2754 -- not a simple identifier, and record max length of name.
2760 else
2766 -- If we got this far, all actuals are identifiers and the list
2767 -- of their names is stored in the Actuals array.
2772 -- If we ran out of formals, that's odd, probably an error
2773 -- which will be detected elsewhere, but abandon the search.
2779 -- If name matches and is in order OK
2784 else
2785 -- If no match, see if it is elsewhere in list and if so
2786 -- flag potential wrong order if type is compatible.
2790 and then
2792 then
2798 -- No match
2806 -- If Formals left over, also probably an error, skip warning
2812 -- Here we give the warning if something was out of order
2815 Error_Msg_N
2822 -------------------------
2823 -- Check_Prefixed_Call --
2824 -------------------------
2833 begin
2834 -- Check whether the call is a prefixed call, with or without
2835 -- additional actuals.
2838 or else
2844 then
2847 then
2848 -- Introduce dereference on object in prefix
2850 New_A :=
2858 then
2859 -- Introduce an implicit 'Access in prefix
2862 Error_Msg_NE
2878 --------------------
2879 -- Insert_Default --
2880 --------------------
2886 begin
2887 -- Missing argument in call, nothing to insert
2892 else
2893 -- Note that we do a full New_Copy_Tree, so that any associated
2894 -- Itypes are properly copied. This may not be needed any more,
2895 -- but it does no harm as a safety measure! Defaults of a generic
2896 -- formal may be out of bounds of the corresponding actual (see
2897 -- cc1311b) and an additional check may be required.
2899 Actval :=
2900 New_Copy_Tree
2907 then
2913 then
2916 then
2917 -- If default is a real literal, do not introduce a
2918 -- conversion whose effect may depend on the run-time
2919 -- size of universal real.
2923 else
2934 -- Resolve aggregates with their base type, to avoid scope
2935 -- anomalies: the subtype was first built in the subprogram
2936 -- declaration, and the current call may be nested.
2940 then
2942 else
2946 else
2949 -- See note above concerning aggregates
2953 then
2956 -- Resolve entities with their own type, which may differ
2957 -- from the type of a reference in a generic context (the
2958 -- view swapping mechanism did not anticipate the re-analysis
2959 -- of default values in calls).
2964 else
2969 -- If default is a tag indeterminate function call, propagate
2970 -- tag to obtain proper dispatching.
2974 then
2980 -- If the default expression raises constraint error, then just
2981 -- silently replace it with an N_Raise_Constraint_Error node,
2982 -- since we already gave the warning on the subprogram spec.
2992 Assoc :=
2997 -- Case of insertion is first named actual
3001 then
3008 else
3012 else
3016 -- Case of insertion is not first named actual
3018 else
3019 Set_Next_Named_Actual
3031 -------------------
3032 -- Same_Ancestor --
3033 -------------------
3039 begin
3042 then
3048 then
3055 --------------------------
3056 -- Static_Concatenation --
3057 --------------------------
3060 begin
3067 -- Concatenation is static when both operands are static
3068 -- and the concatenation operator is a predefined one.
3071 and then
3073 and then
3078 declare
3080 begin
3083 and then
3087 else
3093 -- Start of processing for Resolve_Actuals
3095 begin
3096 Check_Argument_Order;
3099 Check_Prefixed_Call;
3108 -- If we have an error in any actual or formal, indicated by a type
3109 -- of Any_Type, then abandon resolution attempt, and set result type
3110 -- to Any_Type.
3114 then
3119 -- Case where actual is present
3121 -- If the actual is an entity, generate a reference to it now. We
3122 -- do this before the actual is resolved, because a formal of some
3123 -- protected subprogram, or a task discriminant, will be rewritten
3124 -- during expansion, and the reference to the source entity may
3125 -- be lost.
3130 then
3136 then
3146 or else
3148 then
3149 -- If style checking mode on, check match of formal name
3157 -- If the formal is Out or In_Out, do not resolve and expand the
3158 -- conversion, because it is subsequently expanded into explicit
3159 -- temporaries and assignments. However, the object of the
3160 -- conversion can be resolved. An exception is the case of tagged
3161 -- type conversion with a class-wide actual. In that case we want
3162 -- the tag check to occur and no temporary will be needed (no
3163 -- representation change can occur) and the parameter is passed by
3164 -- reference, so we go ahead and resolve the type conversion.
3165 -- Another exception is the case of reference to component or
3166 -- subcomponent of a bit-packed array, in which case we want to
3167 -- defer expansion to the point the in and out assignments are
3168 -- performed.
3173 then
3176 then
3179 then
3181 -- In a view conversion, the conversion must be legal in
3182 -- both directions, and thus both component types must be
3183 -- aliased, or neither (4.6 (8)).
3185 -- The additional rule 4.6 (24.9.2) seems unduly
3186 -- restrictive: the privacy requirement should not apply
3187 -- to generic types, and should be checked in an
3188 -- instance. ARG query is in order ???
3190 Error_Msg_N
3194 elsif
3196 then
3199 then
3200 Error_Msg_N
3203 else
3204 declare
3206 Component_Type
3208 begin
3211 and then
3216 then
3217 Error_Msg_N
3231 then
3235 -- If the actual is a function call that returns a limited
3236 -- unconstrained object that needs finalization, create a
3237 -- transient scope for it, so that it can receive the proper
3238 -- finalization list.
3243 and then Expander_Active
3244 and then
3246 then
3249 -- A small optimization: if one of the actuals is a concatenation
3250 -- create a block around a procedure call to recover stack space.
3251 -- This alleviates stack usage when several procedure calls in
3252 -- the same statement list use concatenation. We do not perform
3253 -- this wrapping for code statements, where the argument is a
3254 -- static string, and we want to preserve warnings involving
3255 -- sequences of such statements.
3259 and then Expander_Active
3260 and then
3264 then
3268 else
3272 and then
3275 then
3276 Error_Msg_N
3289 -- (Ada 2005: AI-251): If the actual is an allocator whose
3290 -- directly designated type is a class-wide interface, we build
3291 -- an anonymous access type to use it as the type of the
3292 -- allocator. Later, when the subprogram call is expanded, if
3293 -- the interface has a secondary dispatch table the expander
3294 -- will add a type conversion to force the correct displacement
3295 -- of the pointer.
3298 declare
3304 begin
3307 then
3315 -- Ada 2005, AI-162:If the actual is an allocator, the
3316 -- innermost enclosing statement is the master of the
3317 -- created object. This needs to be done with expansion
3318 -- enabled only, otherwise the transient scope will not
3319 -- be removed in the expansion of the wrapped construct.
3322 and then Expander_Active
3323 then
3329 -- (Ada 2005): The call may be to a primitive operation of
3330 -- a tagged synchronized type, declared outside of the type.
3331 -- In this case the controlling actual must be converted to
3332 -- its corresponding record type, which is the formal type.
3333 -- The actual may be a subtype, either because of a constraint
3334 -- or because it is a generic actual, so use base type to
3335 -- locate concurrent type.
3340 declare
3343 begin
3346 else
3350 -- Tagged synchronized type (case 1): the actual is a
3351 -- concurrent type
3355 then
3357 Unchecked_Convert_To
3361 -- Tagged synchronized type (case 2): the formal is a
3362 -- concurrent type
3365 and then Present
3370 then
3373 -- Common case
3375 else
3384 -- For mode IN, if actual is an entity, and the type of the formal
3385 -- has warnings suppressed, then we reset Never_Set_In_Source for
3386 -- the calling entity. The reason for this is to catch cases like
3387 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3388 -- uses trickery to modify an IN parameter.
3395 then
3399 -- Perform error checks for IN and IN OUT parameters
3403 -- Check unset reference. For scalar parameters, it is clearly
3404 -- wrong to pass an uninitialized value as either an IN or
3405 -- IN-OUT parameter. For composites, it is also clearly an
3406 -- error to pass a completely uninitialized value as an IN
3407 -- parameter, but the case of IN OUT is trickier. We prefer
3408 -- not to give a warning here. For example, suppose there is
3409 -- a routine that sets some component of a record to False.
3410 -- It is perfectly reasonable to make this IN-OUT and allow
3411 -- either initialized or uninitialized records to be passed
3412 -- in this case.
3414 -- For partially initialized composite values, we also avoid
3415 -- warnings, since it is quite likely that we are passing a
3416 -- partially initialized value and only the initialized fields
3417 -- will in fact be read in the subprogram.
3422 then
3426 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3427 -- actual to a nested call, since this is case of reading an
3428 -- out parameter, which is not allowed.
3433 then
3438 -- Case of OUT or IN OUT parameter
3442 -- For an Out parameter, check for useless assignment. Note
3443 -- that we can't set Last_Assignment this early, because we may
3444 -- kill current values in Resolve_Call, and that call would
3445 -- clobber the Last_Assignment field.
3447 -- Note: call Warn_On_Useless_Assignment before doing the check
3448 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3449 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3450 -- reflects the last assignment, not this one!
3457 then
3462 -- Validate the form of the actual. Note that the call to
3463 -- Is_OK_Variable_For_Out_Formal generates the required
3464 -- reference in this case.
3470 -- What's the following about???
3474 else
3475 Kill_All_Checks;
3484 -- Apply appropriate range checks for in, out, and in-out
3485 -- parameters. Out and in-out parameters also need a separate
3486 -- check, if there is a type conversion, to make sure the return
3487 -- value meets the constraints of the variable before the
3488 -- conversion.
3490 -- Gigi looks at the check flag and uses the appropriate types.
3491 -- For now since one flag is used there is an optimization which
3492 -- might not be done in the In Out case since Gigi does not do
3493 -- any analysis. More thought required about this ???
3497 then
3509 then
3515 then
3521 then
3524 else
3528 -- Ada 2005 (AI-231)
3534 then
3535 Apply_Compile_Time_Constraint_Error
3545 then
3548 Apply_Scalar_Range_Check
3550 else
3551 Apply_Range_Check
3555 else
3561 then
3564 else
3570 -- An actual associated with an access parameter is implicitly
3571 -- converted to the anonymous access type of the formal and must
3572 -- satisfy the legality checks for access conversions.
3576 Error_Msg_N
3581 -- Check bad case of atomic/volatile argument (RM C.6(12))
3585 then
3588 then
3589 Error_Msg_N
3591 N);
3595 then
3596 Error_Msg_N
3598 N);
3602 -- Check that subprograms don't have improper controlling
3603 -- arguments (RM 3.9.2 (9)).
3605 -- A primitive operation may have an access parameter of an
3606 -- incomplete tagged type, but a dispatching call is illegal
3607 -- if the type is still incomplete.
3613 declare
3615 begin
3619 then
3620 Error_Msg_NE
3634 then
3639 then
3641 Error_Msg_NE
3651 and then
3656 -- Disable these checks for call to imported C++ subprograms
3658 and then not
3662 then
3663 Error_Msg_N
3668 then
3670 Error_Msg_NE
3677 -- If it is a named association, treat the selector_name as
3678 -- a proper identifier, and mark the corresponding entity.
3695 -- Case where actual is not present
3697 else
3698 Insert_Default;
3705 -----------------------
3706 -- Resolve_Allocator --
3707 -----------------------
3718 procedure Check_Allocator_Discrim_Accessibility
3721 -- Check that accessibility level associated with an access discriminant
3722 -- initialized in an allocator by the expression Disc_Exp is not deeper
3723 -- than the level of the allocator type Alloc_Typ. An error message is
3724 -- issued if this condition is violated. Specialized checks are done for
3725 -- the cases of a constraint expression which is an access attribute or
3726 -- an access discriminant.
3729 -- If the allocator is an actual in a call, it is allowed to be class-
3730 -- wide when the context is not because it is a controlling actual.
3733 -- Propagate all nested coextensions which are located one nesting
3734 -- level down the tree to the node Root. Example:
3735 --
3736 -- Top_Record
3737 -- Level_1_Coextension
3738 -- Level_2_Coextension
3739 --
3740 -- The algorithm is paired with delay actions done by the Expander. In
3741 -- the above example, assume all coextensions are controlled types.
3742 -- The cycle of analysis, resolution and expansion will yield:
3743 --
3744 -- 1) Analyze Top_Record
3745 -- 2) Analyze Level_1_Coextension
3746 -- 3) Analyze Level_2_Coextension
3747 -- 4) Resolve Level_2_Coextension. The allocator is marked as a
3748 -- coextension.
3749 -- 5) Expand Level_2_Coextension. A temporary variable Temp_1 is
3750 -- generated to capture the allocated object. Temp_1 is attached
3751 -- to the coextension chain of Level_2_Coextension.
3752 -- 6) Resolve Level_1_Coextension. The allocator is marked as a
3753 -- coextension. A forward tree traversal is performed which finds
3754 -- Level_2_Coextension's list and copies its contents into its
3755 -- own list.
3756 -- 7) Expand Level_1_Coextension. A temporary variable Temp_2 is
3757 -- generated to capture the allocated object. Temp_2 is attached
3758 -- to the coextension chain of Level_1_Coextension. Currently, the
3759 -- contents of the list are [Temp_2, Temp_1].
3760 -- 8) Resolve Top_Record. A forward tree traversal is performed which
3761 -- finds Level_1_Coextension's list and copies its contents into
3762 -- its own list.
3763 -- 9) Expand Top_Record. Generate finalization calls for Temp_1 and
3764 -- Temp_2 and attach them to Top_Record's finalization list.
3766 -------------------------------------------
3767 -- Check_Allocator_Discrim_Accessibility --
3768 -------------------------------------------
3770 procedure Check_Allocator_Discrim_Accessibility
3773 is
3774 begin
3777 then
3778 Error_Msg_N
3781 -- When the expression is an Access attribute the level of the prefix
3782 -- object must not be deeper than that of the allocator's type.
3786 = Attribute_Access
3789 then
3790 Error_Msg_N
3792 Disc_Exp);
3794 -- When the expression is an access discriminant the check is against
3795 -- the level of the prefix object.
3801 then
3802 Error_Msg_N
3804 Disc_Exp);
3806 -- All other cases are legal
3808 else
3813 ----------------------------
3814 -- In_Dispatching_Context --
3815 ----------------------------
3819 begin
3825 ----------------------------
3826 -- Propagate_Coextensions --
3827 ----------------------------
3832 -- Copy the contents of list From into list To, preserving the
3833 -- order of elements.
3836 -- Recognize an allocator or a rewritten allocator node and add it
3837 -- along with its nested coextensions to the list of Root.
3839 ---------------
3840 -- Copy_List --
3841 ---------------
3845 begin
3853 -----------------------
3854 -- Process_Allocator --
3855 -----------------------
3860 begin
3861 -- This is a possible rewritten subtype indication allocator. Any
3862 -- nested coextensions will appear as discriminant constraints.
3867 then
3868 declare
3872 begin
3874 Discr_Elmt :=
3884 then
3889 Copy_List
3897 -- There is no need to continue the traversal of this
3898 -- subtree since all the information has already been
3899 -- propagated.
3905 -- Case of either a stand alone allocator or a rewritten allocator
3906 -- with an aggregate.
3908 else
3915 -- Propagate the list of nested coextensions to the Root
3916 -- allocator. This is done through list copy since a single
3917 -- allocator may have multiple coextensions. Do not touch
3918 -- coextensions roots.
3922 then
3927 Copy_List
3932 -- There is no need to continue the traversal of this
3933 -- subtree since all the information has already been
3934 -- propagated.
3940 -- Keep on traversing, looking for the next allocator
3948 -- Start of processing for Propagate_Coextensions
3950 begin
3954 -- Start of processing for Resolve_Allocator
3956 begin
3957 -- Replace general access with specific type
3967 -- For qualified expression, resolve the expression using the
3968 -- given subtype (nothing to do for type mark, subtype indication)
3973 and then not In_Dispatching_Context
3974 then
3975 Error_Msg_N
3982 -- A qualified expression requires an exact match of the type,
3983 -- class-wide matching is not allowed.
3988 then
3992 -- A special accessibility check is needed for allocators that
3993 -- constrain access discriminants. The level of the type of the
3994 -- expression used to constrain an access discriminant cannot be
3995 -- deeper than the type of the allocator (in contrast to access
3996 -- parameters, where the level of the actual can be arbitrary).
3998 -- We can't use Valid_Conversion to perform this check because
3999 -- in general the type of the allocator is unrelated to the type
4000 -- of the access discriminant.
4004 then
4011 then
4014 -- Get the first component expression of the aggregate
4024 else
4028 else
4047 else
4052 else
4061 -- For a subtype mark or subtype indication, freeze the subtype
4063 else
4067 Error_Msg_N
4071 -- A special accessibility check is needed for allocators that
4072 -- constrain access discriminants. The level of the type of the
4073 -- expression used to constrain an access discriminant cannot be
4074 -- deeper than the type of the allocator (in contrast to access
4075 -- parameters, where the level of the actual can be arbitrary).
4076 -- We can't use Valid_Conversion to perform this check because
4077 -- in general the type of the allocator is unrelated to the type
4078 -- of the access discriminant.
4083 then
4093 else
4107 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4108 -- check that the level of the type of the created object is not deeper
4109 -- than the level of the allocator's access type, since extensions can
4110 -- now occur at deeper levels than their ancestor types. This is a
4111 -- static accessibility level check; a run-time check is also needed in
4112 -- the case of an initialized allocator with a class-wide argument (see
4113 -- Expand_Allocator_Expression).
4117 then
4118 declare
4121 begin
4126 else
4135 E);
4141 -- Do not apply Ada 2005 accessibility checks on a class-wide
4142 -- allocator if the type given in the allocator is a formal
4143 -- type. A run-time check will be performed in the instance.
4153 -- Check for allocation from an empty storage pool
4156 declare
4158 begin
4166 -- If the context is an unchecked conversion, as may happen within
4167 -- an inlined subprogram, the allocator is being resolved with its
4168 -- own anonymous type. In that case, if the target type has a specific
4169 -- storage pool, it must be inherited explicitly by the allocator type.
4173 then
4174 Set_Associated_Storage_Pool
4178 -- An erroneous allocator may be rewritten as a raise Program_Error
4179 -- statement.
4183 -- An anonymous access discriminant is the definition of a
4184 -- coextension.
4188 N_Discriminant_Specification
4189 then
4190 -- Avoid marking an allocator as a dynamic coextension if it is
4191 -- within a static construct.
4197 -- Cleanup for potential static coextensions
4199 else
4204 -- There is no need to propagate any nested coextensions if they
4205 -- are marked as static since they will be rewritten on the spot.
4213 ---------------------------
4214 -- Resolve_Arithmetic_Op --
4215 ---------------------------
4217 -- Used for resolving all arithmetic operators except exponentiation
4228 -- We do the resolution using the base type, because intermediate values
4229 -- in expressions always are of the base type, not a subtype of it.
4232 -- Returns True if N is in a context that expects "any real type"
4235 -- Return True iff given type is Integer or universal real/integer
4238 -- Choose type of integer literal in fixed-point operation to conform
4239 -- to available fixed-point type. T is the type of the other operand,
4240 -- which is needed to determine the expected type of N.
4243 -- Set operand type to T if universal
4245 -------------------------------
4246 -- Expected_Type_Is_Any_Real --
4247 -------------------------------
4250 begin
4251 -- N is the expression after "delta" in a fixed_point_definition;
4252 -- see RM-3.5.9(6):
4255 N_Decimal_Fixed_Point_Definition,
4257 -- N is one of the bounds in a real_range_specification;
4258 -- see RM-3.5.7(5):
4260 N_Real_Range_Specification,
4262 -- N is the expression of a delta_constraint;
4263 -- see RM-J.3(3):
4265 N_Delta_Constraint);
4268 -----------------------------
4269 -- Is_Integer_Or_Universal --
4270 -----------------------------
4277 begin
4283 else
4289 then
4300 ----------------------------
4301 -- Set_Mixed_Mode_Operand --
4302 ----------------------------
4308 begin
4311 -- A universal integer literal is resolved as standard integer
4312 -- except in the case of a fixed-point result, where we leave it
4313 -- as universal (to be handled by Exp_Fixd later on)
4317 else
4325 then
4326 -- A universal real can appear in a fixed-type context. We resolve
4327 -- the literal with that context, even though this might raise an
4328 -- exception prematurely (the other operand may be zero).
4335 then
4336 -- Integer arg in mixed-mode operation. Resolve with universal
4337 -- type, in case preference rule must be applied.
4343 then
4344 -- Not a mixed-mode operation, resolve with context
4350 -- N may itself be a mixed-mode operation, so use context type
4357 then
4358 -- Must be (fixed * fixed) operation, operand must have one
4359 -- compatible interpretation.
4367 then
4368 -- C * F(X) in a fixed context, where C is a real literal or a
4369 -- fixed-point expression. F must have either a fixed type
4370 -- interpretation or an integer interpretation, but not both.
4378 else
4386 else
4394 -- Reanalyze the literal with the fixed type of the context. If
4395 -- context is Universal_Fixed, we are within a conversion, leave
4396 -- the literal as a universal real because there is no usable
4397 -- fixed type, and the target of the conversion plays no role in
4398 -- the resolution.
4400 declare
4404 begin
4407 else
4413 then
4415 else
4423 else
4428 ----------------------
4429 -- Set_Operand_Type --
4430 ----------------------
4433 begin
4436 then
4441 -- Start of processing for Resolve_Arithmetic_Op
4443 begin
4448 then
4452 -- Special-case for mixed-mode universal expressions or fixed point
4453 -- type operation: each argument is resolved separately. The same
4454 -- treatment is required if one of the operands of a fixed point
4455 -- operation is universal real, since in this case we don't do a
4456 -- conversion to a specific fixed-point type (instead the expander
4457 -- takes care of the case).
4462 then
4473 or else
4476 then
4481 -- If context is a fixed type and one operand is integer, the
4482 -- other is resolved with the type of the context.
4487 then
4494 then
4498 else
4503 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4504 -- multiplying operators from being used when the expected type is
4505 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4506 -- some cases where the expected type is actually Any_Real;
4507 -- Expected_Type_Is_Any_Real takes care of that case.
4511 then
4515 N_Unchecked_Type_Conversion)
4516 then
4523 else
4526 and then not
4528 N_Unchecked_Type_Conversion)
4529 then
4530 Error_Msg_N
4535 -- The expected type is "any real type" in contexts like
4536 -- type T is delta <universal_fixed-expression> ...
4537 -- in which case we need to set the type to Universal_Real
4538 -- so that static expression evaluation will work properly.
4542 else
4552 then
4557 -- If no previous errors, this is only possible if one operand
4558 -- is overloaded and the context is universal. Resolve as such.
4563 else
4565 and then
4567 then
4571 -- If the context is Universal_Fixed and the operands are also
4572 -- universal fixed, this is an error, unless there is only one
4573 -- applicable fixed_point type (usually duration).
4581 else
4586 else
4591 -- If one of the arguments was resolved to a non-universal type.
4592 -- label the result of the operation itself with the same type.
4593 -- Do the same for the universal argument, if any.
4604 -- Set overflow and division checking bit. Much cleverer code needed
4605 -- here eventually and perhaps the Resolve routines should be separated
4606 -- for the various arithmetic operations, since they will need
4607 -- different processing. ???
4614 -- Give warning if explicit division by zero
4618 then
4624 or else
4627 then
4628 -- Specialize the warning message according to the operation
4632 Apply_Compile_Time_Constraint_Error
4637 Apply_Compile_Time_Constraint_Error
4642 Apply_Compile_Time_Constraint_Error
4646 -- Division by zero can only happen with division, rem,
4647 -- and mod operations.
4653 -- Otherwise just set the flag to check at run time
4655 else
4660 -- If Restriction No_Implicit_Conditionals is active, then it is
4661 -- violated if either operand can be negative for mod, or for rem
4662 -- if both operands can be negative.
4666 then
4667 declare
4674 -- Set if corresponding operand might be negative
4676 begin
4677 Determine_Range
4681 Determine_Range
4685 -- Check if we will be generating conditionals. There are two
4686 -- cases where that can happen, first for REM, the only case
4687 -- is largest negative integer mod -1, where the division can
4688 -- overflow, but we still have to give the right result. The
4689 -- front end generates a test for this annoying case. Here we
4690 -- just test if both operands can be negative (that's what the
4691 -- expander does, so we match its logic here).
4693 -- The second case is mod where either operand can be negative.
4694 -- In this case, the back end has to generate additonal tests.
4697 or else
4699 then
4710 ------------------
4711 -- Resolve_Call --
4712 ------------------
4724 begin
4725 -- The context imposes a unique interpretation with type Typ on a
4726 -- procedure or function call. Find the entity of the subprogram that
4727 -- yields the expected type, and propagate the corresponding formal
4728 -- constraints on the actuals. The caller has established that an
4729 -- interpretation exists, and emitted an error if not unique.
4731 -- First deal with the case of a call to an access-to-subprogram,
4732 -- dereference made explicit in Analyze_Call.
4738 else
4739 -- Find the interpretation whose type (a subprogram type) has a
4740 -- return type that is compatible with the context. Analysis of
4741 -- the node has established that one exists.
4760 -- If the prefix is not an entity, then resolve it
4766 -- For an indirect call, we always invalidate checks, since we do not
4767 -- know whether the subprogram is local or global. Yes we could do
4768 -- better here, e.g. by knowing that there are no local subprograms,
4769 -- but it does not seem worth the effort. Similarly, we kill all
4770 -- knowledge of current constant values.
4772 Kill_Current_Values;
4774 -- If this is a procedure call which is really an entry call, do
4775 -- the conversion of the procedure call to an entry call. Protected
4776 -- operations use the same circuitry because the name in the call
4777 -- can be an arbitrary expression with special resolution rules.
4782 then
4786 -- Kill checks and constant values, as above for indirect case
4787 -- Who knows what happens when another task is activated?
4789 Kill_Current_Values;
4792 -- Normal subprogram call with name established in Resolve
4798 -- Otherwise we must have the case of an overloaded call
4800 else
4803 -- Initialize Nam to prevent warning (we know it will be assigned
4804 -- in the loop below, but the compiler does not know that).
4824 then
4825 -- The prefix is a parameterless function call that returns an access
4826 -- to subprogram. If parameters are present in the current call, add
4827 -- add an explicit dereference. We use the base type here because
4828 -- within an instance these may be subtypes.
4830 -- The dereference is added either in Analyze_Call or here. Should
4831 -- be consolidated ???
4840 -- Check that a call to Current_Task does not occur in an entry body
4843 declare
4846 begin
4848 loop
4851 -- Exclude calls that occur within the default of a formal
4852 -- parameter of the entry, since those are evaluated outside
4853 -- of the body.
4860 then
4862 Error_Msg_NE
4865 Error_Msg_NE
4877 -- Check that a procedure call does not occur in the context of the
4878 -- entry call statement of a conditional or timed entry call. Note that
4879 -- the case of a call to a subprogram renaming of an entry will also be
4880 -- rejected. The test for N not being an N_Entry_Call_Statement is
4881 -- defensive, covering the possibility that the processing of entry
4882 -- calls might reach this point due to later modifications of the code
4883 -- above.
4888 then
4892 -- Ada 2005 (AI-345): If a procedure_call_statement is used
4893 -- for a procedure_or_entry_call, the procedure_name or
4894 -- procedure_prefix of the procedure_call_statement shall denote
4895 -- an entry renamed by a procedure, or (a view of) a primitive
4896 -- subprogram of a limited interface whose first parameter is
4897 -- a controlling parameter.
4902 then
4903 Error_Msg_N
4908 -- Check that this is not a call to a protected procedure or entry from
4909 -- within a protected function.
4915 then
4921 -- Freeze the subprogram name if not in a spec-expression. Note that we
4922 -- freeze procedure calls as well as function calls. Procedure calls are
4923 -- not frozen according to the rules (RM 13.14(14)) because it is
4924 -- impossible to have a procedure call to a non-frozen procedure in pure
4925 -- Ada, but in the code that we generate in the expander, this rule
4926 -- needs extending because we can generate procedure calls that need
4927 -- freezing.
4933 -- For a predefined operator, the type of the result is the type imposed
4934 -- by context, except for a predefined operation on universal fixed.
4935 -- Otherwise The type of the call is the type returned by the subprogram
4936 -- being called.
4943 -- If the subprogram returns an array type, and the context requires the
4944 -- component type of that array type, the node is really an indexing of
4945 -- the parameterless call. Resolve as such. A pathological case occurs
4946 -- when the type of the component is an access to the array type. In
4947 -- this case the call is truly ambiguous.
4950 and then
4955 and then
4958 then
4959 declare
4964 begin
4967 then
4968 Error_Msg_N
4970 else
4976 or else
4978 and then
4980 then
4983 -- Indexed call to a parameterless function
4985 Index_Node :=
4987 Prefix =>
4991 else
4992 -- An Ada 2005 prefixed call to a primitive operation
4993 -- whose first parameter is the prefix. This prefix was
4994 -- prepended to the parameter list, which is actually a
4995 -- list of indices. Remove the prefix in order to build
4996 -- the proper indexed component.
4998 Index_Node :=
5000 Prefix =>
5003 Parameter_Associations =>
5004 New_List
5009 -- Since we are correcting a node classification error made
5010 -- by the parser, we call Replace rather than Rewrite.
5023 else
5027 -- In the case where the call is to an overloaded subprogram, Analyze
5028 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5029 -- such a case Normalize_Actuals needs to be called once more to order
5030 -- the actuals correctly. Otherwise the call will have the ordering
5031 -- given by the last overloaded subprogram whether this is the correct
5032 -- one being called or not.
5039 -- In any case, call is fully resolved now. Reset Overload flag, to
5040 -- prevent subsequent overload resolution if node is analyzed again
5045 -- If we are calling the current subprogram from immediately within its
5046 -- body, then that is the case where we can sometimes detect cases of
5047 -- infinite recursion statically. Do not try this in case restriction
5048 -- No_Recursion is in effect anyway, and do it only for source calls.
5053 -- Issue warning for possible infinite recursion in the absence
5054 -- of the No_Recursion restriction.
5059 then
5060 -- Here we detected and flagged an infinite recursion, so we do
5061 -- not need to test the case below for further warnings. Also if
5062 -- we now have a raise SE node, we are all done.
5068 -- If call is to immediately containing subprogram, then check for
5069 -- the case of a possible run-time detectable infinite recursion.
5071 else
5075 -- Although in general case, recursion is not statically
5076 -- checkable, the case of calling an immediately containing
5077 -- subprogram is easy to catch.
5081 -- If the recursive call is to a parameterless subprogram,
5082 -- then even if we can't statically detect infinite
5083 -- recursion, this is pretty suspicious, and we output a
5084 -- warning. Furthermore, we will try later to detect some
5085 -- cases here at run time by expanding checking code (see
5086 -- Detect_Infinite_Recursion in package Exp_Ch6).
5088 -- If the recursive call is within a handler, do not emit a
5089 -- warning, because this is a common idiom: loop until input
5090 -- is correct, catch illegal input in handler and restart.
5096 then
5097 -- For the case of a procedure call. We give the message
5098 -- only if the call is the first statement in a sequence
5099 -- of statements, or if all previous statements are
5100 -- simple assignments. This is simply a heuristic to
5101 -- decrease false positives, without losing too many good
5102 -- warnings. The idea is that these previous statements
5103 -- may affect global variables the procedure depends on.
5107 then
5108 declare
5110 begin
5122 -- Do not give warning if we are in a conditional context
5124 declare
5126 begin
5132 then
5137 -- Here warning is to be issued
5140 Error_Msg_N
5142 Error_Msg_N
5154 -- If subprogram name is a predefined operator, it was given in
5155 -- functional notation. Replace call node with operator node, so
5156 -- that actuals can be resolved appropriately.
5164 then
5170 -- Create a transient scope if the resulting type requires it
5172 -- There are several notable exceptions:
5174 -- a) In init procs, the transient scope overhead is not needed, and is
5175 -- even incorrect when the call is a nested initialization call for a
5176 -- component whose expansion may generate adjust calls. However, if the
5177 -- call is some other procedure call within an initialization procedure
5178 -- (for example a call to Create_Task in the init_proc of the task
5179 -- run-time record) a transient scope must be created around this call.
5181 -- b) Enumeration literal pseudo-calls need no transient scope
5183 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
5184 -- functions) do not use the secondary stack even though the return
5185 -- type may be unconstrained.
5187 -- d) Calls to a build-in-place function, since such functions may
5188 -- allocate their result directly in a target object, and cases where
5189 -- the result does get allocated in the secondary stack are checked for
5190 -- within the specialized Exp_Ch6 procedures for expanding those
5191 -- build-in-place calls.
5193 -- e) If the subprogram is marked Inline_Always, then even if it returns
5194 -- an unconstrained type the call does not require use of the secondary
5195 -- stack. However, inlining will only take place if the body to inline
5196 -- is already present. It may not be available if e.g. the subprogram is
5197 -- declared in a child instance.
5199 -- If this is an initialization call for a type whose construction
5200 -- uses the secondary stack, and it is not a nested call to initialize
5201 -- a component, we do need to create a transient scope for it. We
5202 -- check for this by traversing the type in Check_Initialization_Call.
5208 then
5214 then
5217 elsif Expander_Active
5220 and then
5222 or else
5224 then
5227 -- If the call appears within the bounds of a loop, it will
5228 -- be rewritten and reanalyzed, nothing left to do here.
5235 and then not Within_Init_Proc
5236 then
5240 -- A protected function cannot be called within the definition of the
5241 -- enclosing protected type.
5246 then
5247 Error_Msg_NE
5251 -- Propagate interpretation to actuals, and add default expressions
5252 -- where needed.
5257 -- Overloaded literals are rewritten as function calls, for purpose of
5258 -- resolution. After resolution, we can replace the call with the
5259 -- literal itself.
5265 -- Avoid validation, since it is a static function call
5271 -- If the subprogram is not global, then kill all saved values and
5272 -- checks. This is a bit conservative, since in many cases we could do
5273 -- better, but it is not worth the effort. Similarly, we kill constant
5274 -- values. However we do not need to do this for internal entities
5275 -- (unless they are inherited user-defined subprograms), since they
5276 -- are not in the business of molesting local values.
5278 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5279 -- kill all checks and values for calls to global subprograms. This
5280 -- takes care of the case where an access to a local subprogram is
5281 -- taken, and could be passed directly or indirectly and then called
5282 -- from almost any context.
5284 -- Note: we do not do this step till after resolving the actuals. That
5285 -- way we still take advantage of the current value information while
5286 -- scanning the actuals.
5288 -- We suppress killing values if we are processing the nodes associated
5289 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5290 -- type kills all the values as part of analyzing the code that
5291 -- initializes the dispatch tables.
5295 or else Suppress_Value_Tracking_On_Call
5300 then
5301 Kill_Current_Values;
5304 -- If we are warning about unread OUT parameters, this is the place to
5305 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5306 -- after the above call to Kill_Current_Values (since that call clears
5307 -- the Last_Assignment field of all local variables).
5312 then
5313 declare
5317 begin
5322 or else
5329 then
5339 -- If the subprogram is a primitive operation, check whether or not
5340 -- it is a correct dispatching call.
5344 then
5349 and then not In_Instance
5350 then
5354 -- If this is a dispatching call, generate the appropriate reference,
5355 -- for better source navigation in GPS.
5359 then
5362 -- Normal case, not a dispatching call
5364 else
5372 -- Check for violation of restriction No_Specific_Termination_Handlers
5373 -- and warn on a potentially blocking call to Abort_Task.
5376 or else
5378 then
5385 -- Issue an error for a call to an eliminated subprogram
5389 -- All done, evaluate call and deal with elaboration issues
5395 -------------------------------
5396 -- Resolve_Character_Literal --
5397 -------------------------------
5403 begin
5404 -- Verify that the character does belong to the type of the context
5409 -- Wide_Wide_Character literals must always be defined, since the set
5410 -- of wide wide character literals is complete, i.e. if a character
5411 -- literal is accepted by the parser, then it is OK for wide wide
5412 -- character (out of range character literals are rejected).
5417 -- Always accept character literal for type Any_Character, which
5418 -- occurs in error situations and in comparisons of literals, both
5419 -- of which should accept all literals.
5424 -- For Standard.Character or a type derived from it, check that
5425 -- the literal is in range
5432 -- For Standard.Wide_Character or a type derived from it, check
5433 -- that the literal is in range
5440 -- For Standard.Wide_Wide_Character or a type derived from it, we
5441 -- know the literal is in range, since the parser checked!
5446 -- If the entity is already set, this has already been resolved in a
5447 -- generic context, or comes from expansion. Nothing else to do.
5452 -- Otherwise we have a user defined character type, and we can use the
5453 -- standard visibility mechanisms to locate the referenced entity.
5455 else
5468 -- If we fall through, then the literal does not match any of the
5469 -- entries of the enumeration type. This isn't just a constraint
5470 -- error situation, it is an illegality (see RM 4.2).
5472 Error_Msg_NE
5476 ---------------------------
5477 -- Resolve_Comparison_Op --
5478 ---------------------------
5480 -- Context requires a boolean type, and plays no role in resolution.
5481 -- Processing identical to that for equality operators. The result
5482 -- type is the base type, which matters when pathological subtypes of
5483 -- booleans with limited ranges are used.
5490 begin
5491 -- If this is an intrinsic operation which is not predefined, use the
5492 -- types of its declared arguments to resolve the possibly overloaded
5493 -- operands. Otherwise the operands are unambiguous and specify the
5494 -- expected type.
5499 else
5513 T = Any_Character
5514 then
5517 else
5524 else
5536 ------------------------------------
5537 -- Resolve_Conditional_Expression --
5538 ------------------------------------
5545 begin
5549 -- If ELSE expression present, just resolve using the determined type
5554 -- If no ELSE expression is present, root type must be Standard.Boolean
5555 -- and we provide a Standard.True result converted to the appropriate
5556 -- Boolean type (in case it is a derived boolean type).
5559 Else_Expr :=
5564 else
5573 -----------------------------------------
5574 -- Resolve_Discrete_Subtype_Indication --
5575 -----------------------------------------
5577 procedure Resolve_Discrete_Subtype_Indication
5580 is
5584 begin
5592 else
5602 Error_Msg_NE
5605 -- Rewrite the constraint as a range of Typ
5606 -- to allow compilation to proceed further.
5618 else
5622 -- Additionally, we must check that the bounds are compatible
5623 -- with the given subtype, which might be different from the
5624 -- type of the context.
5628 -- ??? If the above check statically detects a Constraint_Error
5629 -- it replaces the offending bound(s) of the range R with a
5630 -- Constraint_Error node. When the itype which uses these bounds
5631 -- is frozen the resulting call to Duplicate_Subexpr generates
5632 -- a new temporary for the bounds.
5634 -- Unfortunately there are other itypes that are also made depend
5635 -- on these bounds, so when Duplicate_Subexpr is called they get
5636 -- a forward reference to the newly created temporaries and Gigi
5637 -- aborts on such forward references. This is probably sign of a
5638 -- more fundamental problem somewhere else in either the order of
5639 -- itype freezing or the way certain itypes are constructed.
5641 -- To get around this problem we call Remove_Side_Effects right
5642 -- away if either bounds of R are a Constraint_Error.
5644 declare
5648 begin
5664 -------------------------
5665 -- Resolve_Entity_Name --
5666 -------------------------
5668 -- Used to resolve identifiers and expanded names
5673 begin
5674 -- If garbage from errors, set to Any_Type and return
5681 -- Replace named numbers by corresponding literals. Note that this is
5682 -- the one case where Resolve_Entity_Name must reset the Etype, since
5683 -- it is currently marked as universal.
5693 -- Allow use of subtype only if it is a concurrent type where we are
5694 -- currently inside the body. This will eventually be expanded into a
5695 -- call to Self (for tasks) or _object (for protected objects). Any
5696 -- other use of a subtype is invalid.
5701 then
5703 else
5704 Error_Msg_N
5708 -- Check discriminant use if entity is discriminant in current scope,
5709 -- i.e. discriminant of record or concurrent type currently being
5710 -- analyzed. Uses in corresponding body are unrestricted.
5715 then
5718 -- A parameterless generic function cannot appear in a context that
5719 -- requires resolution.
5730 then
5733 -- In all other cases, just do the possible static evaluation
5735 else
5736 -- A deferred constant that appears in an expression must have a
5737 -- completion, unless it has been removed by in-place expansion of
5738 -- an aggregate.
5744 and then not In_Spec_Expression
5746 then
5751 then
5753 else
5754 Error_Msg_N (
5763 -------------------
5764 -- Resolve_Entry --
5765 -------------------
5777 -- If the bounds of the entry family being called depend on task
5778 -- discriminants, build a new index subtype where a discriminant is
5779 -- replaced with the value of the discriminant of the target task.
5780 -- The target task is the prefix of the entry name in the call.
5782 -----------------------
5783 -- Actual_Index_Type --
5784 -----------------------
5794 -- If the bound is given by a discriminant, replace with a reference
5795 -- to the discriminant of the same name in the target task. If the
5796 -- entry name is the target of a requeue statement and the entry is
5797 -- in the current protected object, the bound to be used is the
5798 -- discriminal of the object (see apply_range_checks for details of
5799 -- the transformation).
5801 -----------------------------
5802 -- Actual_Discriminant_Ref --
5803 -----------------------------
5809 begin
5814 then
5820 then
5823 else
5824 Ref :=
5834 -- Start of processing for Actual_Index_Type
5836 begin
5839 and then
5841 then
5844 else
5858 -- Start of processing of Resolve_Entry
5860 begin
5861 -- Find name of entry being called, and resolve prefix of name
5862 -- with its own type. The prefix can be overloaded, and the name
5863 -- and signature of the entry must be taken into account.
5867 -- Case of dealing with entry family within the current tasks
5871 else
5877 -- Entry call to an entry (or entry family) in the current task. This
5878 -- is legal even though the task will deadlock. Rewrite as call to
5879 -- current task.
5881 -- This can also be a call to an entry in an enclosing task. If this
5882 -- is a single task, we have to retrieve its name, because the scope
5883 -- of the entry is the task type, not the object. If the enclosing
5884 -- task is a task type, the identity of the task is given by its own
5885 -- self variable.
5887 -- Finally this can be a requeue on an entry of the same task or
5888 -- protected object.
5895 then
5896 -- S is an enclosing task or protected object. The concurrent
5897 -- declaration has been converted into a type declaration, and
5898 -- the object itself has an object declaration that follows
5899 -- the type in the same declarative part.
5911 -- Call to current task. Will be transformed into call to Self
5918 New_N :=
5921 Selector_Name =>
5928 then
5929 -- Use the entry name (which must be unique at this point) to find
5930 -- the prefix that returns the corresponding task type or protected
5931 -- type.
5933 declare
5939 begin
5961 -- Up to this point the expression could have been the actual in a
5962 -- simple entry call, and be given by a named association.
5966 else
5972 ------------------------
5973 -- Resolve_Entry_Call --
5974 ------------------------
5986 begin
5987 -- We kill all checks here, because it does not seem worth the effort to
5988 -- do anything better, an entry call is a big operation.
5990 Kill_All_Checks;
5992 -- Processing of the name is similar for entry calls and protected
5993 -- operation calls. Once the entity is determined, we can complete
5994 -- the resolution of the actuals.
5996 -- The selector may be overloaded, in the case of a protected object
5997 -- with overloaded functions. The type of the context is used for
5998 -- resolution.
6003 then
6004 declare
6008 begin
6027 -- Simple entry call
6035 -- Call to member of entry family
6042 -- We cannot in general check the maximum depth of protected entry
6043 -- calls at compile time. But we can tell that any protected entry
6044 -- call at all violates a specified nesting depth of zero.
6050 -- Use context type to disambiguate a protected function that can be
6051 -- called without actuals and that returns an array type, and where
6052 -- the argument list may be an indexing of the returned value.
6057 and then
6065 then
6066 declare
6069 begin
6070 Index_Node :=
6072 Prefix =>
6077 -- Since we are correcting a node classification error made by
6078 -- the parser, we call Replace rather than Rewrite.
6088 -- The operation name may have been overloaded. Order the actuals
6089 -- according to the formals of the resolved entity, and set the
6090 -- return type to that of the operation.
6103 then
6107 -- Verify that a procedure call cannot masquerade as an entry
6108 -- call where an entry call is expected.
6113 then
6118 then
6123 then
6128 -- After resolution, entry calls and protected procedure calls are
6129 -- changed into entry calls, for expansion. The structure of the node
6130 -- does not change, so it can safely be done in place. Protected
6131 -- function calls must keep their structure because they are
6132 -- subexpressions.
6136 -- A protected operation that is not a function may modify the
6137 -- corresponding object, and cannot apply to a constant. If this
6138 -- is an internal call, the prefix is the type itself.
6144 then
6145 Error_Msg_N
6147 Entry_Name);
6161 -- Protected functions can return on the secondary stack, in which
6162 -- case we must trigger the transient scope mechanism.
6164 elsif Expander_Active
6166 then
6171 -------------------------
6172 -- Resolve_Equality_Op --
6173 -------------------------
6175 -- Both arguments must have the same type, and the boolean context does
6176 -- not participate in the resolution. The first pass verifies that the
6177 -- interpretation is not ambiguous, and the type of the left argument is
6178 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
6179 -- are strings or aggregates, allocators, or Null, they are ambiguous even
6180 -- though they carry a single (universal) type. Diagnose this case here.
6188 -- In the case of allocators, make a last-ditch attempt to find a single
6189 -- access type with the right designated type. This is semantically
6190 -- dubious, and of no interest to any real code, but c48008a makes it
6191 -- all worthwhile.
6193 -----------------------------
6194 -- Find_Unique_Access_Type --
6195 -----------------------------
6202 begin
6207 else
6219 then
6232 -- Start of processing for Resolve_Equality_Op
6234 begin
6246 then
6249 else
6259 then
6272 -- If the unique type is a class-wide type then it will be expanded
6273 -- into a dispatching call to the predefined primitive. Therefore we
6274 -- check here for potential violation of such restriction.
6280 if Warn_On_Redundant_Constructs
6285 then
6294 -- If this is an inequality, it may be the implicit inequality
6295 -- created for a user-defined operation, in which case the corres-
6296 -- ponding equality operation is not intrinsic, and the operation
6297 -- cannot be constant-folded. Else fold.
6302 or else Is_Intrinsic_Subprogram
6304 then
6309 then
6313 -- Ada 2005: If one operand is an anonymous access type, convert the
6314 -- other operand to it, to ensure that the underlying types match in
6315 -- the back-end. Same for access_to_subprogram, and the conversion
6316 -- verifies that the types are subtype conformant.
6318 -- We apply the same conversion in the case one of the operands is a
6319 -- private subtype of the type of the other.
6321 -- Why the Expander_Active test here ???
6323 if Expander_Active
6324 and then
6328 then
6348 ----------------------------------
6349 -- Resolve_Explicit_Dereference --
6350 ----------------------------------
6359 begin
6364 -- Use the context type to select the prefix that has the correct
6365 -- designated type.
6376 else
6377 -- If no interpretation covers the designated type of the prefix,
6378 -- this is the pathological case where not all implementations of
6379 -- the prefix allow the interpretation of the node as a call. Now
6380 -- that the expected type is known, Remove other interpretations
6381 -- from prefix, rewrite it as a call, and resolve again, so that
6382 -- the proper call node is generated.
6393 New_N :=
6395 Name =>
6408 else
6416 -- If the designated type is a packed unconstrained array type, and the
6417 -- explicit dereference is not in the context of an attribute reference,
6418 -- then we must compute and set the actual subtype, since it is needed
6419 -- by Gigi. The reason we exclude the attribute case is that this is
6420 -- handled fine by Gigi, and in fact we use such attributes to build the
6421 -- actual subtype. We also exclude generated code (which builds actual
6422 -- subtypes directly if they are needed).
6429 then
6433 -- Note: No Eval processing is required for an explicit dereference,
6434 -- because such a name can never be static.
6438 -------------------------------
6439 -- Resolve_Indexed_Component --
6440 -------------------------------
6448 begin
6451 -- Use the context type to select the prefix that yields the correct
6452 -- component type.
6454 declare
6461 begin
6468 and then Covers
6470 then
6479 else
6485 else
6496 else
6503 -- If prefix is access type, dereference to get real array type.
6504 -- Note: we do not apply an access check because the expander always
6505 -- introduces an explicit dereference, and the check will happen there.
6511 -- If name was overloaded, set component type correctly now
6512 -- If a misplaced call to an entry family (which has no index types)
6513 -- return. Error will be diagnosed from calling context.
6517 else
6524 -- The prefix may have resolved to a string literal, in which case its
6525 -- etype has a special representation. This is only possible currently
6526 -- if the prefix is a static concatenation, written in functional
6527 -- notation.
6532 else
6539 else
6548 -- Do not generate the warning on suspicious index if we are analyzing
6549 -- package Ada.Tags; otherwise we will report the warning with the
6550 -- Prims_Ptr field of the dispatch table.
6553 or else not
6555 Ada_Tags)
6556 then
6562 -----------------------------
6563 -- Resolve_Integer_Literal --
6564 -----------------------------
6567 begin
6572 --------------------------------
6573 -- Resolve_Intrinsic_Operator --
6574 --------------------------------
6582 begin
6592 -- If the operand type is private, rewrite with suitable conversions on
6593 -- the operands and the result, to expose the proper underlying numeric
6594 -- type.
6601 else
6617 then
6618 -- Add explicit conversion where needed, and save interpretations in
6619 -- case operands are overloaded.
6626 else
6632 else
6642 else
6647 --------------------------------------
6648 -- Resolve_Intrinsic_Unary_Operator --
6649 --------------------------------------
6651 procedure Resolve_Intrinsic_Unary_Operator
6654 is
6659 begin
6678 else
6683 ------------------------
6684 -- Resolve_Logical_Op --
6685 ------------------------
6690 begin
6693 -- Predefined operations on scalar types yield the base type. On the
6694 -- other hand, logical operations on arrays yield the type of the
6695 -- arguments (and the context).
6699 else
6703 -- The following test is required because the operands of the operation
6704 -- may be literals, in which case the resulting type appears to be
6705 -- compatible with a signed integer type, when in fact it is compatible
6706 -- only with modular types. If the context itself is universal, the
6707 -- operation is illegal.
6715 Error_Msg_N
6722 then
6737 ---------------------------
6738 -- Resolve_Membership_Op --
6739 ---------------------------
6741 -- The context can only be a boolean type, and does not determine
6742 -- the arguments. Arguments should be unambiguous, but the preference
6743 -- rule for universal types applies.
6753 -- Analysis has determined a unique type for the left operand.
6754 -- Use it to resolve the disjuncts.
6756 ----------------------------
6757 -- Resolve_Set_Membership --
6758 ----------------------------
6763 begin
6769 -- Alternative is an expression, a range
6770 -- or a subtype mark.
6774 then
6782 -- Start of processing for Resolve_Membership_Op
6784 begin
6790 Resolve_Set_Membership;
6794 and then
6798 then
6801 -- Ada 2005 (AI-251): Support the following case:
6803 -- type I is interface;
6804 -- type T is tagged ...
6806 -- function Test (O : I'Class) is
6807 -- begin
6808 -- return O in T'Class.
6809 -- end Test;
6811 -- In this case we have nothing else to do. The membership test will be
6812 -- done at run-time.
6819 then
6822 else
6831 then
6837 else
6845 ------------------
6846 -- Resolve_Null --
6847 ------------------
6852 begin
6853 -- Handle restriction against anonymous null access values This
6854 -- restriction can be turned off using -gnatdj.
6856 -- Ada 2005 (AI-231): Remove restriction
6859 and then not Debug_Flag_J
6862 then
6863 -- In the common case of a call which uses an explicitly null value
6864 -- for an access parameter, give specialized error message.
6867 N_Function_Call)
6868 then
6869 Error_Msg_N
6872 -- Standard message for all other cases (are there any?)
6874 else
6875 Error_Msg_N
6880 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
6881 -- assignment to a null-excluding object
6886 then
6888 Insert_Action
6893 else
6900 -- In a distributed context, null for a remote access to subprogram may
6901 -- need to be replaced with a special record aggregate. In this case,
6902 -- return after having done the transformation.
6907 then
6911 -- The null literal takes its type from the context
6916 -----------------------
6917 -- Resolve_Op_Concat --
6918 -----------------------
6922 -- We wish to avoid deep recursion, because concatenations are often
6923 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
6924 -- operands nonrecursively until we find something that is not a simple
6925 -- concatenation (A in this case). We resolve that, and then walk back
6926 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
6927 -- to do the rest of the work at each level. The Parent pointers allow
6928 -- us to avoid recursion, and thus avoid running out of memory. See also
6929 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
6934 begin
6935 -- The following code is equivalent to:
6937 -- Resolve_Op_Concat_First (NN, Typ);
6938 -- Resolve_Op_Concat_Arg (N, ...);
6939 -- Resolve_Op_Concat_Rest (N, Typ);
6941 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
6942 -- operand is a concatenation.
6944 -- Walk down left operands
6946 loop
6955 -- Now (given the above example) NN is A&B and Op1 is A
6957 -- First resolve Op1 ...
6961 -- ... then walk NN back up until we reach N (where we started), calling
6962 -- Resolve_Op_Concat_Rest along the way.
6964 loop
6971 ---------------------------
6972 -- Resolve_Op_Concat_Arg --
6973 ---------------------------
6975 procedure Resolve_Op_Concat_Arg
6980 is
6983 begin
6985 if Is_Comp
6989 then
6991 else
6998 then
7001 else
7006 else
7010 then
7011 declare
7016 begin
7021 -- Special-case the error message when the overloading is
7022 -- caused by a function that yields an array and can be
7023 -- called without parameters.
7028 Error_Msg_NE
7030 Error_Msg_NE
7034 else
7035 Error_Msg_N
7044 then
7045 Error_Msg_N -- CODEFIX
7063 else
7068 else
7075 -----------------------------
7076 -- Resolve_Op_Concat_First --
7077 -----------------------------
7084 begin
7085 -- The parser folds an enormous sequence of concatenations of string
7086 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
7087 -- in the right operand. If the expression resolves to a predefined "&"
7088 -- operator, all is well. Otherwise, the parser's folding is wrong, so
7089 -- we give an error. See P_Simple_Expression in Par.Ch4.
7094 then
7109 ----------------------------
7110 -- Resolve_Op_Concat_Rest --
7111 ----------------------------
7117 begin
7126 -- If this is not a static concatenation, but the result is a string
7127 -- type (and not an array of strings) ensure that static string operands
7128 -- have their subtypes properly constructed.
7132 then
7138 ----------------------
7139 -- Resolve_Op_Expon --
7140 ----------------------
7145 begin
7146 -- Catch attempts to do fixed-point exponentiation with universal
7147 -- operands, which is a case where the illegality is not caught during
7148 -- normal operator analysis.
7159 then
7166 then
7170 -- We do the resolution using the base type, because intermediate values
7171 -- in expressions always are of the base type, not a subtype of it.
7183 -- Set overflow checking bit. Much cleverer code needed here eventually
7184 -- and perhaps the Resolve routines should be separated for the various
7185 -- arithmetic operations, since they will need different processing. ???
7194 --------------------
7195 -- Resolve_Op_Not --
7196 --------------------
7202 -- This function determines if the parent node is a boolean operator
7203 -- or operation (comparison op, membership test, or short circuit form)
7204 -- and the not in question is the left operand of this operation.
7205 -- Note that if the not is in parens, then false is returned.
7207 -----------------------
7208 -- Parent_Is_Boolean --
7209 -----------------------
7212 begin
7216 else
7218 when N_Op_And |
7219 N_Op_Eq |
7220 N_Op_Ge |
7221 N_Op_Gt |
7222 N_Op_Le |
7223 N_Op_Lt |
7224 N_Op_Ne |
7225 N_Op_Or |
7226 N_Op_Xor |
7227 N_In |
7228 N_Not_In |
7229 N_And_Then |
7230 N_Or_Else =>
7240 -- Start of processing for Resolve_Op_Not
7242 begin
7243 -- Predefined operations on scalar types yield the base type. On the
7244 -- other hand, logical operations on arrays yield the type of the
7245 -- arguments (and the context).
7249 else
7253 -- Straightforward case of incorrect arguments
7260 -- Special case of probable missing parens
7264 Error_Msg_N
7267 else
7268 Error_Msg_N
7275 -- OK resolution of not
7277 else
7278 -- Warn if non-boolean types involved. This is a case like not a < b
7279 -- where a and b are modular, where we will get (not a) < b and most
7280 -- likely not (a < b) was intended.
7282 if Warn_On_Questionable_Missing_Parens
7284 and then Parent_Is_Boolean
7285 then
7289 -- Warn on double negation if checking redundant constructs
7291 if Warn_On_Redundant_Constructs
7296 then
7300 -- Complete resolution and evaluation of NOT
7310 -----------------------------
7311 -- Resolve_Operator_Symbol --
7312 -----------------------------
7314 -- Nothing to be done, all resolved already
7320 begin
7324 ----------------------------------
7325 -- Resolve_Qualified_Expression --
7326 ----------------------------------
7334 begin
7337 -- A qualified expression requires an exact match of the type,
7338 -- class-wide matching is not allowed. However, if the qualifying
7339 -- type is specific and the expression has a class-wide type, it
7340 -- may still be okay, since it can be the result of the expansion
7341 -- of a call to a dispatching function, so we also have to check
7342 -- class-wideness of the type of the expression's original node.
7345 or else
7349 then
7353 -- If the target type is unconstrained, then we reset the type of
7354 -- the result from the type of the expression. For other cases, the
7355 -- actual subtype of the expression is the target type.
7359 then
7366 -------------------
7367 -- Resolve_Range --
7368 -------------------
7374 begin
7382 -- We have to check the bounds for being within the base range as
7383 -- required for a non-static context. Normally this is automatic and
7384 -- done as part of evaluating expressions, but the N_Range node is an
7385 -- exception, since in GNAT we consider this node to be a subexpression,
7386 -- even though in Ada it is not. The circuit in Sem_Eval could check for
7387 -- this, but that would put the test on the main evaluation path for
7388 -- expressions.
7393 -- Check for an ambiguous range over character literals. This will
7394 -- happen with a membership test involving only literals.
7402 -- If bounds are static, constant-fold them, so size computations
7403 -- are identical between front-end and back-end. Do not perform this
7404 -- transformation while analyzing generic units, as type information
7405 -- would then be lost when reanalyzing the constant node in the
7406 -- instance.
7419 --------------------------
7420 -- Resolve_Real_Literal --
7421 --------------------------
7426 begin
7427 -- Special processing for fixed-point literals to make sure that the
7428 -- value is an exact multiple of small where this is required. We
7429 -- skip this for the universal real case, and also for generic types.
7435 then
7436 declare
7443 begin
7444 -- Case of literal is not an exact multiple of the Small
7448 -- For a source program literal for a decimal fixed-point
7449 -- type, this is statically illegal (RM 4.9(36)).
7454 then
7458 -- Generate a warning if literal from source
7461 and then Warn_On_Bad_Fixed_Value
7462 then
7463 Error_Msg_N
7465 N);
7468 -- Replace literal by a value that is the exact representation
7469 -- of a value of the type, i.e. a multiple of the small value,
7470 -- by truncation, since Machine_Rounds is false for all GNAT
7471 -- fixed-point types (RM 4.9(38)).
7481 -- In all cases, set the corresponding integer field
7487 -- Now replace the actual type by the expected type as usual
7493 -----------------------
7494 -- Resolve_Reference --
7495 -----------------------
7500 begin
7501 -- Replace general access with specific type
7509 -- If we are taking the reference of a volatile entity, then treat
7510 -- it as a potential modification of this entity. This is much too
7511 -- conservative, but is necessary because remove side effects can
7512 -- result in transformations of normal assignments into reference
7513 -- sequences that otherwise fail to notice the modification.
7520 --------------------------------
7521 -- Resolve_Selected_Component --
7522 --------------------------------
7537 -- Check whether this is the initialization of a component within an
7538 -- init proc (by assignment or call to another init proc). If true,
7539 -- there is no need for a discriminant check.
7541 --------------------
7542 -- Init_Component --
7543 --------------------
7546 begin
7547 return Inside_Init_Proc
7553 -- Start of processing for Resolve_Selected_Component
7555 begin
7558 -- Use the context type to select the prefix that has a selector
7559 -- of the correct name and type.
7567 else
7573 -- The visible components of a class-wide type are those of
7574 -- the root type.
7584 then
7591 else
7595 Error_Msg_N
7600 else
7603 -- There may be an implicit dereference. Retrieve
7604 -- designated record type.
7608 else
7614 -- Resolution chooses the new interpretation.
7615 -- Find the component with the right name.
7620 loop
7642 else
7643 -- Resolve prefix with its type
7648 -- Generate cross-reference. We needed to wait until full overloading
7649 -- resolution was complete to do this, since otherwise we can't tell if
7650 -- we are an lvalue or not.
7654 else
7658 -- If prefix is an access type, the node will be transformed into an
7659 -- explicit dereference during expansion. The type of the node is the
7660 -- designated type of that of the prefix.
7665 else
7671 or else
7678 and then not Init_Component
7679 then
7687 -- If the prefix is a record conversion, this may be a renamed
7688 -- discriminant whose bounds differ from those of the original
7689 -- one, so we must ensure that a range check is performed.
7694 then
7698 -- Note: No Eval processing is required, because the prefix is of a
7699 -- record type, or protected type, and neither can possibly be static.
7703 -------------------
7704 -- Resolve_Shift --
7705 -------------------
7712 begin
7713 -- We do the resolution using the base type, because intermediate values
7714 -- in expressions always are of the base type, not a subtype of it.
7727 ---------------------------
7728 -- Resolve_Short_Circuit --
7729 ---------------------------
7736 begin
7740 -- Check for issuing warning for always False assert/check, this happens
7741 -- when assertions are turned off, in which case the pragma Assert/Check
7742 -- was transformed into:
7744 -- if False and then <condition> then ...
7746 -- and we detect this pattern
7748 if Warn_On_Assertion_Failure
7755 then
7756 declare
7759 begin
7762 then
7763 -- Don't want to warn if original condition is explicit False
7765 declare
7767 Original_Node
7768 (Expression
7770 begin
7773 then
7775 else
7776 -- Issue warning. Note that we don't want to make this
7777 -- an unconditional warning, because if the assert is
7778 -- within deleted code we do not want the warning. But
7779 -- we do not want the deletion of the IF/AND-THEN to
7780 -- take this message with it. We achieve this by making
7781 -- sure that the expanded code points to the Sloc of
7782 -- the expression, not the original pragma.
7788 -- Similar processing for Check pragma
7792 then
7793 -- Don't want to warn if original condition is explicit False
7795 declare
7797 Original_Node
7798 (Expression
7801 begin
7804 then
7806 else
7814 -- Continue with processing of short circuit
7823 -------------------
7824 -- Resolve_Slice --
7825 -------------------
7833 begin
7836 -- Use the context type to select the prefix that yields the correct
7837 -- array type.
7839 declare
7846 begin
7854 then
7862 else
7867 else
7878 else
7888 -- If the prefix is an access to an unconstrained array, we must use
7889 -- the actual subtype of the object to perform the index checks. The
7890 -- object denoted by the prefix is implicit in the node, so we build
7891 -- an explicit representation for it in order to compute the actual
7892 -- subtype.
7897 declare
7901 begin
7911 then
7914 -- If the name is a selected component that depends on discriminants,
7915 -- build an actual subtype for it. This can happen only when the name
7916 -- itself is overloaded; otherwise the actual subtype is created when
7917 -- the selected component is analyzed.
7920 and then Full_Analysis
7922 then
7923 declare
7926 begin
7931 -- Maybe this should just be "else", instead of checking for the
7932 -- specific case of slice??? This is needed for the case where
7933 -- the prefix is an Image attribute, which gets expanded to a
7934 -- slice, and so has a constrained subtype which we want to use
7935 -- for the slice range check applied below (the range check won't
7936 -- get done if the unconstrained subtype of the 'Image is used).
7942 -- If name was overloaded, set slice type correctly now
7946 -- If the range is specified by a subtype mark, no resolution is
7947 -- necessary. Else resolve the bounds, and apply needed checks.
7955 -- Do not apply the range check to nodes associated with the
7956 -- frontend expansion of the dispatch table. We first check
7957 -- if Ada.Tags is already loaded to void the addition of an
7958 -- undesired dependence on such run-time unit.
7960 and then
7962 or else not
7968 then
7983 ----------------------------
7984 -- Resolve_String_Literal --
7985 ----------------------------
7996 begin
7997 -- For a string appearing in a concatenation, defer creation of the
7998 -- string_literal_subtype until the end of the resolution of the
7999 -- concatenation, because the literal may be constant-folded away. This
8000 -- is a useful optimization for long concatenation expressions.
8002 -- If the string is an aggregate built for a single character (which
8003 -- happens in a non-static context) or a is null string to which special
8004 -- checks may apply, we build the subtype. Wide strings must also get a
8005 -- string subtype if they come from a one character aggregate. Strings
8006 -- generated by attributes might be static, but it is often hard to
8007 -- determine whether the enclosing context is static, so we generate
8008 -- subtypes for them as well, thus losing some rarer optimizations ???
8009 -- Same for strings that come from a static conversion.
8011 Need_Check :=
8020 -- If the resolving type is itself a string literal subtype, we can just
8021 -- reuse it, since there is no point in creating another.
8027 and then not Need_Check
8029 N_Attribute_Reference,
8030 N_Qualified_Expression,
8031 N_Type_Conversion)
8032 then
8035 -- Otherwise we must create a string literal subtype. Note that the
8036 -- whole idea of string literal subtypes is simply to avoid the need
8037 -- for building a full fledged array subtype for each literal.
8039 else
8045 or else Need_Check
8046 then
8053 then
8059 -- The validity of a null string has been checked in the call to
8060 -- Eval_String_Literal.
8065 -- Always accept string literal with component type Any_Character, which
8066 -- occurs in error situations and in comparisons of literals, both of
8067 -- which should accept all literals.
8072 -- If the type is bit-packed, then we always transform the string
8073 -- literal into a full fledged aggregate.
8078 -- Deal with cases of Wide_Wide_String, Wide_String, and String
8080 else
8081 -- For Standard.Wide_Wide_String, or any other type whose component
8082 -- type is Standard.Wide_Wide_Character, we know that all the
8083 -- characters in the string must be acceptable, since the parser
8084 -- accepted the characters as valid character literals.
8089 -- For the case of Standard.String, or any other type whose component
8090 -- type is Standard.Character, we must make sure that there are no
8091 -- wide characters in the string, i.e. that it is entirely composed
8092 -- of characters in range of type Character.
8094 -- If the string literal is the result of a static concatenation, the
8095 -- test has already been performed on the components, and need not be
8096 -- repeated.
8100 then
8104 -- If we are out of range, post error. This is one of the
8105 -- very few places that we place the flag in the middle of
8106 -- a token, right under the offending wide character. Not
8107 -- quite clear if this is right wrt wide character encoding
8108 -- sequences, but it's only an error message!
8110 Error_Msg
8117 -- For the case of Standard.Wide_String, or any other type whose
8118 -- component type is Standard.Wide_Character, we must make sure that
8119 -- there are no wide characters in the string, i.e. that it is
8120 -- entirely composed of characters in range of type Wide_Character.
8122 -- If the string literal is the result of a static concatenation,
8123 -- the test has already been performed on the components, and need
8124 -- not be repeated.
8128 then
8132 -- If we are out of range, post error. This is one of the
8133 -- very few places that we place the flag in the middle of
8134 -- a token, right under the offending wide character.
8136 -- This is not quite right, because characters in general
8137 -- will take more than one character position ???
8139 Error_Msg
8146 -- If the root type is not a standard character, then we will convert
8147 -- the string into an aggregate and will let the aggregate code do
8148 -- the checking. Standard Wide_Wide_Character is also OK here.
8150 else
8154 -- See if the component type of the array corresponding to the string
8155 -- has compile time known bounds. If yes we can directly check
8156 -- whether the evaluation of the string will raise constraint error.
8157 -- Otherwise we need to transform the string literal into the
8158 -- corresponding character aggregate and let the aggregate
8159 -- code do the checking.
8163 -- Check for the case of full range, where we are definitely OK
8169 -- Here the range is not the complete base type range, so check
8171 declare
8179 begin
8182 then
8188 then
8189 Apply_Compile_Time_Constraint_Error
8201 -- If we got here we meed to transform the string literal into the
8202 -- equivalent qualified positional array aggregate. This is rather
8203 -- heavy artillery for this situation, but it is hard work to avoid.
8205 declare
8210 begin
8211 -- Build the character literals, we give them source locations that
8212 -- correspond to the string positions, which is a bit tricky given
8213 -- the possible presence of wide character escape sequences.
8227 -- Should we have a call to Skip_Wide here ???
8228 -- ??? else
8229 -- Skip_Wide (P);
8237 Expression =>
8244 -----------------------------
8245 -- Resolve_Subprogram_Info --
8246 -----------------------------
8249 begin
8253 -----------------------------
8254 -- Resolve_Type_Conversion --
8255 -----------------------------
8266 begin
8267 if not Conv_OK
8269 then
8275 -- Mixed-mode operation involving a literal. Context must be a fixed
8276 -- type which is applied to the literal subsequently.
8284 or else
8286 then
8287 -- Return if expression is ambiguous
8292 -- If nothing else, the available fixed type is Duration
8294 else
8298 -- Resolve the real operand with largest available precision
8302 else
8308 -- If the operand is a literal (it could be a non-static and
8309 -- illegal exponentiation) check whether the use of Duration
8310 -- is potentially inaccurate.
8315 then
8316 Error_Msg_N
8319 Rop);
8320 Error_Msg_N
8327 then
8330 else
8339 -- Note: we do the Eval_Type_Conversion call before applying the
8340 -- required checks for a subtype conversion. This is important, since
8341 -- both are prepared under certain circumstances to change the type
8342 -- conversion to a constraint error node, but in the case of
8343 -- Eval_Type_Conversion this may reflect an illegality in the static
8344 -- case, and we would miss the illegality (getting only a warning
8345 -- message), if we applied the type conversion checks first.
8349 -- Even when evaluation is not possible, we may be able to simplify the
8350 -- conversion or its expression. This needs to be done before applying
8351 -- checks, since otherwise the checks may use the original expression
8352 -- and defeat the simplifications. This is specifically the case for
8353 -- elimination of the floating-point Truncation attribute in
8354 -- float-to-int conversions.
8358 -- If after evaluation we still have a type conversion, then we may need
8359 -- to apply checks required for a subtype conversion.
8361 -- Skip these type conversion checks if universal fixed operands
8362 -- operands involved, since range checks are handled separately for
8363 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
8369 then
8373 -- Issue warning for conversion of simple object to its own type. We
8374 -- have to test the original nodes, since they may have been rewritten
8375 -- by various optimizations.
8379 if Warn_On_Redundant_Constructs
8382 and then not In_Instance
8383 then
8387 -- If the node is part of a larger expression, the Target_Type
8388 -- may not be the original type of the node if the context is a
8389 -- condition. Recover original type to see if conversion is needed.
8393 then
8398 and then
8400 or else
8403 then
8405 Error_Msg_NE -- CODEFIX
8410 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
8411 -- No need to perform any interface conversion if the type of the
8412 -- expression coincides with the target type.
8415 and then Expander_Active
8417 then
8418 declare
8422 begin
8434 -- Conversion from interface type
8438 -- Ada 2005 (AI-217): Handle entities from limited views
8444 Error_Msg_N
8446 N);
8449 and then not
8452 then
8456 Error_Msg_N
8458 N);
8460 else
8464 -- Conversion to interface type
8468 -- Handle subtypes
8472 then
8476 if not Interface_Present_In_Ancestor
8479 then
8482 -- The static analysis is not enough to know if the
8483 -- interface is implemented or not. Hence we must pass
8484 -- the work to the expander to generate code to evaluate
8485 -- the conversion at run-time.
8489 else
8492 Error_Msg_N
8497 else
8505 ----------------------
8506 -- Resolve_Unary_Op --
8507 ----------------------
8516 begin
8517 -- Deal with intrinsic unary operators
8523 then
8528 -- Deal with universal cases
8531 or else
8533 then
8540 -- Generate warning for expressions like abs (x mod 2)
8542 if Warn_On_Redundant_Constructs
8544 then
8548 Error_Msg_N
8553 -- Deal with reference generation
8559 -- Set overflow checking bit. Much cleverer code needed here eventually
8560 -- and perhaps the Resolve routines should be separated for the various
8561 -- arithmetic operations, since they will need different processing ???
8569 -- Generate warning for expressions like -5 mod 3 for integers. No need
8570 -- to worry in the floating-point case, since parens do not affect the
8571 -- result so there is no point in giving in a warning.
8573 declare
8582 begin
8583 if Warn_On_Questionable_Missing_Parens
8587 then
8590 -- We are looking for cases where the right operand is not
8591 -- parenthesized, and is a binary operator, multiply, divide, or
8592 -- mod. These are the cases where the grouping can affect results.
8596 then
8597 -- For mod, we always give the warning, since the value is
8598 -- affected by the parenthesization (e.g. (-5) mod 315 /=
8599 -- -(5 mod 315)). But for the other cases, the only concern is
8600 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
8601 -- overflows, but (-2) * 64 does not). So we try to give the
8602 -- message only when overflow is possible.
8606 then
8611 else
8617 else
8621 -- Note that the test below is deliberately excluding the
8622 -- largest negative number, since that is a potentially
8623 -- troublesome case (e.g. -2 * x, where the result is the
8624 -- largest negative integer has an overflow with 2 * x).
8631 -- For the multiplication case, the only case we have to worry
8632 -- about is when (-a)*b is exactly the largest negative number
8633 -- so that -(a*b) can cause overflow. This can only happen if
8634 -- a is a power of 2, and more generally if any operand is a
8635 -- constant that is not a power of 2, then the parentheses
8636 -- cannot affect whether overflow occurs. We only bother to
8637 -- test the left most operand
8639 -- Loop looking at left operands for one that has known value
8646 -- Operand value of 0 or 1 skips warning
8651 -- Otherwise check power of 2, if power of 2, warn, if
8652 -- anything else, skip warning.
8654 else
8658 else
8667 -- Keep looking at left operands
8672 -- For rem or "/" we can only have a problematic situation
8673 -- if the divisor has a value of minus one or one. Otherwise
8674 -- overflow is impossible (divisor > 1) or we have a case of
8675 -- division by zero in any case.
8680 then
8684 -- If we fall through warning should be issued
8686 Error_Msg_N
8693 ----------------------------------
8694 -- Resolve_Unchecked_Expression --
8695 ----------------------------------
8697 procedure Resolve_Unchecked_Expression
8700 is
8701 begin
8706 ---------------------------------------
8707 -- Resolve_Unchecked_Type_Conversion --
8708 ---------------------------------------
8710 procedure Resolve_Unchecked_Type_Conversion
8713 is
8719 begin
8720 -- Resolve operand using its own type
8727 ------------------------------
8728 -- Rewrite_Operator_As_Call --
8729 ------------------------------
8736 begin
8743 New_N :=
8754 ------------------------------
8755 -- Rewrite_Renamed_Operator --
8756 ------------------------------
8758 procedure Rewrite_Renamed_Operator
8762 is
8767 begin
8768 -- Rewrite the operator node using the real operator, not its renaming.
8769 -- Exclude user-defined intrinsic operations of the same name, which are
8770 -- treated separately and rewritten as calls.
8774 then
8781 -- Indicate that both the original entity and its renaming are
8782 -- referenced at this point.
8793 -- If the context type is private, add the appropriate conversions
8794 -- so that the operator is applied to the full view. This is done
8795 -- in the routines that resolve intrinsic operators,
8799 then
8801 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
8802 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
8815 then
8816 -- Operator renames a user-defined operator of the same name. Use
8817 -- the original operator in the node, which is the one that Gigi
8818 -- knows about.
8825 -----------------------
8826 -- Set_Slice_Subtype --
8827 -----------------------
8829 -- Build an implicit subtype declaration to represent the type delivered
8830 -- by the slice. This is an abbreviated version of an array subtype. We
8831 -- define an index subtype for the slice, using either the subtype name
8832 -- or the discrete range of the slice. To be consistent with index usage
8833 -- elsewhere, we create a list header to hold the single index. This list
8834 -- is not otherwise attached to the syntax tree.
8845 begin
8849 else
8850 -- We force the evaluation of a range. This is definitely needed in
8851 -- the renamed case, and seems safer to do unconditionally. Note in
8852 -- any case that since we will create and insert an Itype referring
8853 -- to this range, we must make sure any side effect removal actions
8854 -- are inserted before the Itype definition.
8883 -- The Etype of the existing Slice node is reset to this slice subtype.
8884 -- Its bounds are obtained from its first index.
8888 -- In the packed case, this must be immediately frozen
8890 -- Couldn't we always freeze here??? and if we did, then the above
8891 -- call to Check_Compile_Time_Size could be eliminated, which would
8892 -- be nice, because then that routine could be made private to Freeze.
8894 -- Why the test for In_Spec_Expression here ???
8902 --------------------------------
8903 -- Set_String_Literal_Subtype --
8904 --------------------------------
8912 begin
8926 -- The low bound is set from the low bound of the corresponding
8927 -- index type. Note that we do not store the high bound in the
8928 -- string literal subtype, but it can be deduced if necessary
8929 -- from the length and the low bound.
8933 else
8934 Set_String_Literal_Low_Bound
8938 -- Build bona fide subtype for the string, and wrap it in an
8939 -- unchecked conversion, because the backend expects the
8940 -- String_Literal_Subtype to have a static lower bound.
8942 declare
8948 Right_Opnd =>
8956 begin
8957 Index_Subtype :=
8964 -- In the context, the Index_Type may already have a constraint,
8965 -- so use common base type on string subtype. The base type may
8966 -- be used when generating attributes of the string, for example
8967 -- in the context of a slice assignment.
8992 ------------------------------
8993 -- Simplify_Type_Conversion --
8994 ------------------------------
8997 begin
8999 declare
9004 begin
9006 and then
9013 -- Special processing required if the conversion is the expression
9014 -- of a Truncation attribute reference. In this case we replace:
9016 -- ityp (ftyp'Truncation (x))
9018 -- by
9020 -- ityp (x)
9022 -- with the Float_Truncate flag set, which is more efficient
9024 then
9033 -----------------------------
9034 -- Unique_Fixed_Point_Type --
9035 -----------------------------
9044 -- Give error messages for true ambiguity. Messages are posted on node
9045 -- N, and entities T1, T2 are the possible interpretations.
9047 -----------------------
9048 -- Fixed_Point_Error --
9049 -----------------------
9052 begin
9058 -- Start of processing for Unique_Fixed_Point_Type
9060 begin
9061 -- The operations on Duration are visible, so Duration is always a
9062 -- possible interpretation.
9066 -- Look for fixed-point types in enclosing scopes
9075 then
9077 Fixed_Point_Error;
9079 else
9090 -- Look for visible fixed type declarations in the context
9102 then
9104 Fixed_Point_Error;
9106 else
9120 else
9127 ----------------------
9128 -- Valid_Conversion --
9129 ----------------------
9131 function Valid_Conversion
9135 is
9139 function Conversion_Check
9142 -- Little routine to post Msg if Valid is False, returns Valid value
9144 function Valid_Tagged_Conversion
9147 -- Specifically test for validity of tagged conversions
9150 -- Check index and component conformance, and accessibility levels
9151 -- if the component types are anonymous access types (Ada 2005)
9153 ----------------------
9154 -- Conversion_Check --
9155 ----------------------
9157 function Conversion_Check
9160 is
9161 begin
9169 ----------------------------
9170 -- Valid_Array_Conversion --
9171 ----------------------------
9174 is
9189 begin
9190 -- Error if wrong number of dimensions
9192 if
9194 then
9195 Error_Msg_N
9199 -- Number of dimensions matches
9201 else
9202 -- Loop through indexes of the two arrays
9210 -- Error if index types are incompatible
9216 then
9217 Error_Msg_N
9219 Operand);
9227 -- If component types have same base type, all set
9232 -- Here if base types of components are not the same. The only
9233 -- time this is allowed is if we have anonymous access types.
9235 -- The conversion of arrays of anonymous access types can lead
9236 -- to dangling pointers. AI-392 formalizes the accessibility
9237 -- checks that must be applied to such conversions to prevent
9238 -- out-of-scope references.
9240 elsif
9242 or else
9245 and then
9247 then
9250 then
9255 Operand);
9262 -- Conversion not allowed because of accessibility levels
9264 else
9269 else
9273 -- All other cases where component base types do not match
9275 else
9276 Error_Msg_N
9278 Operand);
9282 -- Check that component subtypes statically match. For numeric
9283 -- types this means that both must be either constrained or
9284 -- unconstrained. For enumeration types the bounds must match.
9285 -- All of this is checked in Subtypes_Statically_Match.
9287 if not Subtypes_Statically_Match
9289 then
9290 Error_Msg_N
9299 -----------------------------
9300 -- Valid_Tagged_Conversion --
9301 -----------------------------
9303 function Valid_Tagged_Conversion
9306 is
9307 begin
9308 -- Upward conversions are allowed (RM 4.6(22))
9312 then
9315 -- Downward conversion are allowed if the operand is class-wide
9316 -- (RM 4.6(23)).
9320 then
9325 then
9326 return
9330 -- Ada 2005 (AI-251): The conversion to/from interface types is
9331 -- always valid
9336 -- If the operand is a class-wide type obtained through a limited_
9337 -- with clause, and the context includes the non-limited view, use
9338 -- it to determine whether the conversion is legal.
9344 then
9349 then
9352 else
9353 Error_Msg_NE
9360 -- Start of processing for Valid_Conversion
9362 begin
9366 declare
9373 begin
9374 -- Remove procedure calls, which syntactically cannot appear in
9375 -- this context, but which cannot be removed by type checking,
9376 -- because the context does not impose a type.
9378 -- When compiling for VMS, spurious ambiguities can be produced
9379 -- when arithmetic operations have a literal operand and return
9380 -- System.Address or a descendant of it. These ambiguities are
9381 -- otherwise resolved by the context, but for conversions there
9382 -- is no context type and the removal of the spurious operations
9383 -- must be done explicitly here.
9385 -- The node may be labelled overloaded, but still contain only
9386 -- one interpretation because others were discarded in previous
9387 -- filters. If this is the case, retain the single interpretation
9388 -- if legal.
9396 then
9397 -- More than one candidate interpretation is available
9407 then
9434 Error_Msg_N -- CODEFIX
9438 Error_Msg_N -- CODEFIX
9450 -- Numeric types
9454 -- A universal fixed expression can be converted to any numeric type
9459 -- Also no need to check when in an instance or inlined body, because
9460 -- the legality has been established when the template was analyzed.
9461 -- Furthermore, numeric conversions may occur where only a private
9462 -- view of the operand type is visible at the instantiation point.
9463 -- This results in a spurious error if we check that the operand type
9464 -- is a numeric type.
9466 -- Note: in a previous version of this unit, the following tests were
9467 -- applied only for generated code (Comes_From_Source set to False),
9468 -- but in fact the test is required for source code as well, since
9469 -- this situation can arise in source code.
9474 -- Otherwise we need the conversion check
9476 else
9477 return Conversion_Check
9482 -- Array types
9488 then
9489 Error_Msg_N
9492 else
9496 -- Ada 2005 (AI-251): Anonymous access types where target references an
9497 -- interface type.
9500 or else
9503 then
9504 -- Check the static accessibility rule of 4.6(17). Note that the
9505 -- check is not enforced when within an instance body, since the
9506 -- RM requires such cases to be caught at run time.
9511 then
9512 -- In an instance, this is a run-time check, but one we know
9513 -- will fail, so generate an appropriate warning. The raise
9514 -- will be generated by Expand_N_Type_Conversion.
9517 Error_Msg_N
9519 Operand);
9520 Error_Msg_N
9522 else
9523 Error_Msg_N
9525 Operand);
9529 -- Special accessibility checks are needed in the case of access
9530 -- discriminants declared for a limited type.
9534 then
9535 -- When the operand is a selected access discriminant the check
9536 -- needs to be made against the level of the object denoted by
9537 -- the prefix of the selected name (Object_Access_Level handles
9538 -- checking the prefix of the operand for this case).
9543 then
9544 -- In an instance, this is a run-time check, but one we know
9545 -- will fail, so generate an appropriate warning. The raise
9546 -- will be generated by Expand_N_Type_Conversion.
9549 Error_Msg_N
9552 Error_Msg_N
9554 else
9555 Error_Msg_N
9562 -- The case of a reference to an access discriminant from
9563 -- within a limited type declaration (which will appear as
9564 -- a discriminal) is always illegal because the level of the
9565 -- discriminant is considered to be deeper than any (nameable)
9566 -- access type.
9573 then
9574 Error_Msg_N
9576 Operand);
9584 -- General and anonymous access types
9588 and then
9589 Conversion_Check
9592 E_Access_Subprogram_Type
9594 E_Access_Protected_Subprogram_Type,
9596 then
9599 then
9600 Error_Msg_N
9605 -- Check the static accessibility rule of 4.6(17). Note that the
9606 -- check is not enforced when within an instance body, since the RM
9607 -- requires such cases to be caught at run time.
9611 then
9614 then
9615 -- In an instance, this is a run-time check, but one we know
9616 -- will fail, so generate an appropriate warning. The raise
9617 -- will be generated by Expand_N_Type_Conversion.
9620 Error_Msg_N
9622 Operand);
9623 Error_Msg_N
9626 else
9627 -- Avoid generation of spurious error message
9630 Error_Msg_N
9632 Operand);
9638 -- Special accessibility checks are needed in the case of access
9639 -- discriminants declared for a limited type.
9643 then
9645 -- When the operand is a selected access discriminant the check
9646 -- needs to be made against the level of the object denoted by
9647 -- the prefix of the selected name (Object_Access_Level handles
9648 -- checking the prefix of the operand for this case).
9653 then
9654 -- In an instance, this is a run-time check, but one we know
9655 -- will fail, so generate an appropriate warning. The raise
9656 -- will be generated by Expand_N_Type_Conversion.
9659 Error_Msg_N
9662 Error_Msg_N
9664 Operand);
9666 else
9667 Error_Msg_N
9674 -- The case of a reference to an access discriminant from
9675 -- within a limited type declaration (which will appear as
9676 -- a discriminal) is always illegal because the level of the
9677 -- discriminant is considered to be deeper than any (nameable)
9678 -- access type.
9684 then
9685 Error_Msg_N
9687 Operand);
9693 -- In the presence of limited_with clauses we have to use non-limited
9694 -- views, if available.
9698 -- Helper function to handle limited views
9700 --------------------------
9701 -- Full_Designated_Type --
9702 --------------------------
9707 begin
9708 -- Handle the limited view of a type
9713 then
9715 else
9720 -- Local Declarations
9728 -- Start of processing for Check_Limited
9730 begin
9734 else
9736 Error_Msg_NE
9741 -- Ada 2005 AI-384: legality rule is symmetric in both
9742 -- designated types. The conversion is legal (with possible
9743 -- constraint check) if either designated type is
9744 -- unconstrained.
9747 or else
9749 and then
9752 then
9753 -- Special case, if Value_Size has been used to make the
9754 -- sizes different, the conversion is not allowed even
9755 -- though the subtypes statically match.
9760 then
9761 Error_Msg_NE
9764 Error_Msg_NE
9769 -- Normal case where conversion is allowed
9771 else
9775 else
9776 Error_Msg_NE
9784 -- Access to subprogram types. If the operand is an access parameter,
9785 -- the type has a deeper accessibility that any master, and cannot
9786 -- be assigned. We must make an exception if the conversion is part
9787 -- of an assignment and the target is the return object of an extended
9788 -- return statement, because in that case the accessibility check
9789 -- takes place after the return.
9793 then
9797 and then
9801 then
9802 Error_Msg_N
9804 Operand);
9805 Error_Msg_N
9808 Operand);
9810 Error_Msg_NE
9815 -- Check that the designated types are subtype conformant
9821 -- Check the static accessibility rule of 4.6(20)
9825 then
9826 Error_Msg_N
9828 Operand);
9830 -- Check that if the operand type is declared in a generic body,
9831 -- then the target type must be declared within that same body
9832 -- (enforces last sentence of 4.6(20)).
9835 declare
9841 begin
9848 Error_Msg_N
9857 -- Remote subprogram access types
9861 then
9862 -- It is valid to convert from one RAS type to another provided
9863 -- that their specification statically match.
9865 Check_Subtype_Conformant
9868 Old_Id =>
9870 Err_Loc =>
9871 N);
9874 -- If both are tagged types, check legality of view conversions
9878 then
9881 -- Types derived from the same root type are convertible
9886 -- In an instance or an inlined body, there may be inconsistent
9887 -- views of the same type, or of types derived from a common root.
9890 and then
9893 then
9896 -- Special check for common access type error case
9900 then
9905 else