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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
83 -----------------------
84 -- Local Subprograms --
85 -----------------------
87 -- Second pass (top-down) type checking and overload resolution procedures
88 -- Typ is the type required by context. These procedures propagate the type
89 -- information recursively to the descendants of N. If the node is not
90 -- overloaded, its Etype is established in the first pass. If overloaded,
91 -- the Resolve routines set the correct type. For arith. operators, the
92 -- Etype is the base type of the context.
94 -- Note that Resolve_Attribute is separated off in Sem_Attr
96 function Bad_Unordered_Enumeration_Reference
99 -- Node N contains a potentially dubious reference to type T, either an
100 -- explicit comparison, or an explicit range. This function returns True
101 -- if the type T is an enumeration type for which No pragma Order has been
102 -- given, and the reference N is not in the same extended source unit as
103 -- the declaration of T.
106 -- Enforce the restrictions on the use of discriminants when constraining
107 -- a component of a discriminated type (record or concurrent type).
110 -- Given a node for an operator associated with type T, check that
111 -- the operator is visible. Operators all of whose operands are
112 -- universal must be checked for visibility during resolution
113 -- because their type is not determinable based on their operands.
115 procedure Check_Fully_Declared_Prefix
118 -- Check that the type of the prefix of a dereference is not incomplete
121 -- Given a call node, N, which is known to occur immediately within the
122 -- subprogram being called, determines whether it is a detectable case of
123 -- an infinite recursion, and if so, outputs appropriate messages. Returns
124 -- True if an infinite recursion is detected, and False otherwise.
127 -- If the type of the object being initialized uses the secondary stack
128 -- directly or indirectly, create a transient scope for the call to the
129 -- init proc. This is because we do not create transient scopes for the
130 -- initialization of individual components within the init proc itself.
131 -- Could be optimized away perhaps?
134 -- N is the node for a logical operator. If the operator is predefined, and
135 -- the root type of the operands is Standard.Boolean, then a check is made
136 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
137 -- the style check for Style_Check_Boolean_And_Or.
140 -- Determine whether E is an access type declared by an access declaration,
141 -- and not an (anonymous) allocator type.
144 -- Utility to check whether the entity for an operator is a predefined
145 -- operator, in which case the expression is left as an operator in the
146 -- tree (else it is rewritten into a call). An instance of an intrinsic
147 -- conversion operation may be given an operator name, but is not treated
148 -- like an operator. Note that an operator that is an imported back-end
149 -- builtin has convention Intrinsic, but is expected to be rewritten into
150 -- a call, so such an operator is not treated as predefined by this
151 -- predicate.
154 -- If a default expression in entry call N depends on the discriminants
155 -- of the task, it must be replaced with a reference to the discriminant
156 -- of the task being called.
158 procedure Resolve_Op_Concat_Arg
163 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
164 -- concatenation operator. The operand is either of the array type or of
165 -- the component type. If the operand is an aggregate, and the component
166 -- type is composite, this is ambiguous if component type has aggregates.
169 -- Does the first part of the work of Resolve_Op_Concat
172 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
173 -- has been resolved. See Resolve_Op_Concat for details.
210 function Operator_Kind
213 -- Utility to map the name of an operator into the corresponding Node. Used
214 -- by other node rewriting procedures.
217 -- Resolve actuals of call, and add default expressions for missing ones.
218 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
219 -- called subprogram.
222 -- Called from Resolve_Call, when the prefix denotes an entry or element
223 -- of entry family. Actuals are resolved as for subprograms, and the node
224 -- is rebuilt as an entry call. Also called for protected operations. Typ
225 -- is the context type, which is used when the operation is a protected
226 -- function with no arguments, and the return value is indexed.
229 -- A call to a user-defined intrinsic operator is rewritten as a call to
230 -- the corresponding predefined operator, with suitable conversions. Note
231 -- that this applies only for intrinsic operators that denote predefined
232 -- operators, not ones that are intrinsic imports of back-end builtins.
235 -- Ditto, for unary operators (arithmetic ones and "not" on signed
236 -- integer types for VMS).
239 -- If an operator node resolves to a call to a user-defined operator,
240 -- rewrite the node as a function call.
242 procedure Make_Call_Into_Operator
246 -- Inverse transformation: if an operator is given in functional notation,
247 -- then after resolving the node, transform into an operator node, so
248 -- that operands are resolved properly. Recall that predefined operators
249 -- do not have a full signature and special resolution rules apply.
251 procedure Rewrite_Renamed_Operator
255 -- An operator can rename another, e.g. in an instantiation. In that
256 -- case, the proper operator node must be constructed and resolved.
259 -- The String_Literal_Subtype is built for all strings that are not
260 -- operands of a static concatenation operation. If the argument is
261 -- not a N_String_Literal node, then the call has no effect.
264 -- Build subtype of array type, with the range specified by the slice
267 -- Called after N has been resolved and evaluated, but before range checks
268 -- have been applied. Currently simplifies a combination of floating-point
269 -- to integer conversion and Truncation attribute.
272 -- A universal_fixed expression in an universal context is unambiguous if
273 -- there is only one applicable fixed point type. Determining whether there
274 -- is only one requires a search over all visible entities, and happens
275 -- only in very pathological cases (see 6115-006).
277 -------------------------
278 -- Ambiguous_Character --
279 -------------------------
284 begin
288 -- First the ones in Standard
293 -- Include Wide_Wide_Character in Ada 2005 mode
299 -- Now any other types that match
309 -------------------------
310 -- Analyze_And_Resolve --
311 -------------------------
314 begin
320 begin
325 -- Versions with check(s) suppressed
327 procedure Analyze_And_Resolve
331 is
334 begin
336 declare
338 begin
345 declare
350 begin
358 else
359 declare
361 begin
369 and then Scope_Is_Transient
370 then
371 -- This can only happen if a transient scope was created for an inner
372 -- expression, which will be removed upon completion of the analysis
373 -- of an enclosing construct. The transient scope must have the
374 -- suppress status of the enclosing environment, not of this Analyze
375 -- call.
378 Scope_Suppress;
382 procedure Analyze_And_Resolve
385 is
388 begin
390 declare
392 begin
399 declare
404 begin
412 else
413 declare
415 begin
424 Scope_Suppress;
428 ----------------------------------------
429 -- Bad_Unordered_Enumeration_Reference --
430 ----------------------------------------
432 function Bad_Unordered_Enumeration_Reference
435 is
436 begin
439 and then Warn_On_Unordered_Enumeration_Type
444 ----------------------------
445 -- Check_Discriminant_Use --
446 ----------------------------
454 begin
455 -- Any use in a spec-expression is legal
462 -- Discriminant cannot be used to constrain a scalar type
469 then
474 -- The following check catches the unusual case where a
475 -- discriminant appears within an index constraint that is part of
476 -- a larger expression within a constraint on a component, e.g. "C
477 -- : Int range 1 .. F (new A(1 .. D))". For now we only check case
478 -- of record components, and note that a similar check should also
479 -- apply in the case of discriminant constraints below. ???
481 -- Note that the check for N_Subtype_Declaration below is to
482 -- detect the valid use of discriminants in the constraints of a
483 -- subtype declaration when this subtype declaration appears
484 -- inside the scope of a record type (which is syntactically
485 -- illegal, but which may be created as part of derived type
486 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
487 -- for more info.
491 and then not
493 and then
495 N_Subtype_Declaration)
497 then
498 Error_Msg_N
503 -- Detect a common error:
505 -- type R (D : Positive := 100) is record
506 -- Name : String (1 .. D);
507 -- end record;
509 -- The default value causes an object of type R to be allocated
510 -- with room for Positive'Last characters. The RM does not mandate
511 -- the allocation of the maximum size, but that is what GNAT does
512 -- so we should warn the programmer that there is a problem.
521 -- Return True if type T has a large enough range that any
522 -- array whose index type covered the whole range of the type
523 -- would likely raise Storage_Error.
525 ------------------------
526 -- Large_Storage_Type --
527 ------------------------
530 begin
531 -- The type is considered large if its bounds are known at
532 -- compile time and if it requires at least as many bits as
533 -- a Positive to store the possible values.
537 and then
542 -- Start of processing for Check_Large
544 begin
545 -- Check that the Disc has a large range
551 -- If the enclosing type is limited, we allocate only the
552 -- default value, not the maximum, and there is no need for
553 -- a warning.
559 -- Check that it is the high bound
563 then
567 -- Check the array allows a large range at this bound. First
568 -- find the array
582 -- Next, find the dimension
590 loop
599 -- Now, check the dimension has a large range
605 -- Warn about the danger
607 Error_Msg_N
617 -- Legal case is in index or discriminant constraint
620 N_Discriminant_Association)
621 then
623 Error_Msg_N
628 then
629 Error_Msg_N
635 -- Otherwise, context is an expression. It should not be within (i.e. a
636 -- subexpression of) a constraint for a component.
638 else
642 N_Subtype_Indication,
643 N_Entry_Declaration)
644 loop
650 -- If the discriminant is used in an expression that is a bound of a
651 -- scalar type, an Itype is created and the bounds are attached to
652 -- its range, not to the original subtype indication. Such use is of
653 -- course a double fault.
657 N_Derived_Type_Definition)
660 -- The constraint itself may be given by a subtype indication,
661 -- rather than by a more common discrete range.
664 and then
668 then
669 Error_Msg_N
675 --------------------------------
676 -- Check_For_Visible_Operator --
677 --------------------------------
680 begin
682 Error_Msg_NE -- CODEFIX
684 Error_Msg_N -- CODEFIX
689 ----------------------------------
690 -- Check_Fully_Declared_Prefix --
691 ----------------------------------
693 procedure Check_Fully_Declared_Prefix
696 is
697 begin
698 -- Check that the designated type of the prefix of a dereference is
699 -- not an incomplete type. This cannot be done unconditionally, because
700 -- dereferences of private types are legal in default expressions. This
701 -- case is taken care of in Check_Fully_Declared, called below. There
702 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
704 -- This consideration also applies to similar checks for allocators,
705 -- qualified expressions, and type conversions.
707 -- An additional exception concerns other per-object expressions that
708 -- are not directly related to component declarations, in particular
709 -- representation pragmas for tasks. These will be per-object
710 -- expressions if they depend on discriminants or some global entity.
711 -- If the task has access discriminants, the designated type may be
712 -- incomplete at the point the expression is resolved. This resolution
713 -- takes place within the body of the initialization procedure, where
714 -- the discriminant is replaced by its discriminal.
718 then
721 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
722 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
723 -- Analyze_Object_Renaming, and Freeze_Entity.
729 E_Incomplete_Type
731 then
733 else
738 ------------------------------
739 -- Check_Infinite_Recursion --
740 ------------------------------
747 -- Check whether list of actuals is identical to list of formals of
748 -- called function (which is also the enclosing scope).
750 ------------------------
751 -- Same_Argument_List --
752 ------------------------
759 begin
762 else
771 then
782 -- Start of processing for Check_Infinite_Recursion
784 begin
785 -- Special case, if this is a procedure call and is a call to the
786 -- current procedure with the same argument list, then this is for
787 -- sure an infinite recursion and we insert a call to raise SE.
791 and then Same_Argument_List
792 then
793 declare
795 begin
799 then
810 -- If not that special case, search up tree, quitting if we reach a
811 -- construct (e.g. a conditional) that tells us that this is not a
812 -- case for an infinite recursion warning.
815 loop
818 -- If no parent, then we were not inside a subprogram, this can for
819 -- example happen when processing certain pragmas in a spec. Just
820 -- return False in this case.
826 -- Done if we get to subprogram body, this is definitely an infinite
827 -- recursion case if we did not find anything to stop us.
831 -- If appearing in conditional, result is false
834 N_And_Then,
835 N_Case_Expression,
836 N_Case_Statement,
837 N_If_Expression,
838 N_If_Statement)
839 then
844 then
845 -- If the call is the expression of a return statement and the
846 -- actuals are identical to the formals, it's worth a warning.
847 -- However, we skip this if there is an immediately preceding
848 -- raise statement, since the call is never executed.
850 -- Furthermore, this corresponds to a common idiom:
852 -- function F (L : Thing) return Boolean is
853 -- begin
854 -- raise Program_Error;
855 -- return F (L);
856 -- end F;
858 -- for generating a stub function
861 and then Same_Argument_List
862 then
865 -- OK, return statement is in a statement list, look for raise
867 declare
870 begin
871 -- Skip past N_Freeze_Entity nodes generated by expansion
876 loop
880 -- If no raise statement, give warning. We look at the
881 -- original node, because in the case of "raise ... with
882 -- ...", the node has been transformed into a call.
885 and then
893 else
904 -------------------------------
905 -- Check_Initialization_Call --
906 -------------------------------
912 -- Check whether the creation of an object of the type will involve
913 -- use of the secondary stack. If T is a record type, this is true
914 -- if the expression for some component uses the secondary stack, e.g.
915 -- through a call to a function that returns an unconstrained value.
916 -- False if T is controlled, because cleanups occur elsewhere.
918 -------------
919 -- Uses_SS --
920 -------------
927 begin
928 -- Normally we want to use the underlying type, but if it's not set
929 -- then continue with T.
946 then
947 -- The expression for a dynamic component may be rewritten
948 -- as a dereference, so retrieve original node.
952 -- Return True if the expression is a call to a function
953 -- (including an attribute function such as Image, or a
954 -- user-defined operator) with a result that requires a
955 -- transient scope.
962 then
975 else
980 -- Start of processing for Check_Initialization_Call
982 begin
983 -- Establish a transient scope if the type needs it
990 ---------------------------------------
991 -- Check_No_Direct_Boolean_Operators --
992 ---------------------------------------
995 begin
998 then
999 -- Restriction only applies to original source code
1011 ------------------------------
1012 -- Check_Parameterless_Call --
1013 ------------------------------
1019 -- If the prefix is of an access_to_subprogram type, the node must be
1020 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1021 -- interpretations are access to subprograms.
1023 ---------------------------
1024 -- Prefix_Is_Access_Subp --
1025 ---------------------------
1031 begin
1032 -- If the context is an attribute reference that can apply to
1033 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1039 then
1044 return
1047 else
1052 then
1063 -- Start of processing for Check_Parameterless_Call
1065 begin
1066 -- Defend against junk stuff if errors already detected
1073 then
1080 -- If the context expects a value, and the name is a procedure, this is
1081 -- most likely a missing 'Access. Don't try to resolve the parameterless
1082 -- call, error will be caught when the outer call is analyzed.
1087 and then
1089 N_Function_Call,
1090 N_Procedure_Call_Statement)
1091 then
1095 -- Rewrite as call if overloadable entity that is (or could be, in the
1096 -- overloaded case) a function call. If we know for sure that the entity
1097 -- is an enumeration literal, we do not rewrite it.
1099 -- If the entity is the name of an operator, it cannot be a call because
1100 -- operators cannot have default parameters. In this case, this must be
1101 -- a string whose contents coincide with an operator name. Set the kind
1102 -- of the node appropriately.
1110 -- Rewrite as call if it is an explicit dereference of an expression of
1111 -- a subprogram access type, and the subprogram type is not that of a
1112 -- procedure or entry.
1114 or else
1117 -- Rewrite as call if it is a selected component which is a function,
1118 -- this is the case of a call to a protected function (which may be
1119 -- overloaded with other protected operations).
1121 or else
1124 or else
1126 E_Procedure)
1129 -- If one of the above three conditions is met, rewrite as call. Apply
1130 -- the rewriting only once.
1132 then
1135 then
1137 -- This may be a prefixed call that was not fully analyzed, e.g.
1138 -- an actual in an instance.
1143 then
1153 -- If overloaded, overload set belongs to new copy
1157 -- Change node to parameterless function call (note that the
1158 -- Parameter_Associations associations field is left set to Empty,
1159 -- its normal default value since there are no parameters)
1177 -----------------------------
1178 -- Is_Definite_Access_Type --
1179 -----------------------------
1183 begin
1189 ----------------------
1190 -- Is_Predefined_Op --
1191 ----------------------
1194 begin
1195 -- Predefined operators are intrinsic subprograms
1201 -- A call to a back-end builtin is never a predefined operator
1212 -----------------------------
1213 -- Make_Call_Into_Operator --
1214 -----------------------------
1216 procedure Make_Call_Into_Operator
1220 is
1235 -- If the operand is not universal, and the operator is given by an
1236 -- expanded name, verify that the operand has an interpretation with a
1237 -- type defined in the given scope of the operator.
1240 -- Find a type of the given class in package Pack that contains the
1241 -- operator.
1243 ---------------------------
1244 -- Operand_Type_In_Scope --
1245 ---------------------------
1252 begin
1256 else
1270 ---------------
1271 -- Type_In_P --
1272 ---------------
1278 -- Verify that node is not part of the type declaration for the
1279 -- candidate type, which would otherwise be invisible.
1281 -------------
1282 -- In_Decl --
1283 -------------
1289 begin
1298 else
1301 loop
1304 else
1313 -- Start of processing for Type_In_P
1315 begin
1316 -- If the context type is declared in the prefix package, this is the
1317 -- desired base type.
1322 else
1326 and then not In_Decl
1327 then
1338 -- Start of processing for Make_Call_Into_Operator
1340 begin
1343 -- Binary operator
1353 -- Unary operator
1355 else
1361 -- If the operator is denoted by an expanded name, and the prefix is
1362 -- not Standard, but the operator is a predefined one whose scope is
1363 -- Standard, then this is an implicit_operator, inserted as an
1364 -- interpretation by the procedure of the same name. This procedure
1365 -- overestimates the presence of implicit operators, because it does
1366 -- not examine the type of the operands. Verify now that the operand
1367 -- type appears in the given scope. If right operand is universal,
1368 -- check the other operand. In the case of concatenation, either
1369 -- argument can be the component type, so check the type of the result.
1370 -- If both arguments are literals, look for a type of the right kind
1371 -- defined in the given scope. This elaborate nonsense is brought to
1372 -- you courtesy of b33302a. The type itself must be frozen, so we must
1373 -- find the type of the proper class in the given scope.
1375 -- A final wrinkle is the multiplication operator for fixed point types,
1376 -- which is defined in Standard only, and not in the scope of the
1377 -- fixed point type itself.
1382 -- If the entity being called is defined in the given package, it is
1383 -- a renaming of a predefined operator, and known to be legal.
1387 then
1390 -- Visibility does not need to be checked in an instance: if the
1391 -- operator was not visible in the generic it has been diagnosed
1392 -- already, else there is an implicit copy of it in the instance.
1400 then
1405 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1406 -- available.
1411 then
1414 else
1423 and then Is_Binary
1425 then
1431 -- Verify that the scope contains a type that corresponds to
1432 -- the given literal. Optimize the case where Pack is Standard.
1454 else
1463 else
1472 then
1475 -- If the type is defined elsewhere, and the operator is not
1476 -- defined in the given scope (by a renaming declaration, e.g.)
1477 -- then this is an error as well. If an extension of System is
1478 -- present, and the type may be defined there, Pack must be
1479 -- System itself.
1486 then
1489 else
1495 then
1502 Error_Msg_NE
1507 -- Detect a mismatch between the context type and the result type
1508 -- in the named package, which is otherwise not detected if the
1509 -- operands are universal. Check is only needed if source entity is
1510 -- an operator, not a function that renames an operator.
1517 and then not In_Instance
1518 then
1521 or else
1523 then
1524 -- Already checked above
1528 -- Operator may be defined in an extension of System
1532 then
1535 else
1536 -- Could we use Wrong_Type here??? (this would require setting
1537 -- Etype (N) to the actual type found where Typ was expected).
1548 else
1552 -- If this is a call to a function that renames a predefined equality,
1553 -- the renaming declaration provides a type that must be used to
1554 -- resolve the operands. This must be done now because resolution of
1555 -- the equality node will not resolve any remaining ambiguity, and it
1556 -- assumes that the first operand is not overloaded.
1561 then
1569 -- Do rewrite setting Comes_From_Source on the result if the original
1570 -- call came from source. Although it is not strictly the case that the
1571 -- operator as such comes from the source, logically it corresponds
1572 -- exactly to the function call in the source, so it should be marked
1573 -- this way (e.g. to make sure that validity checks work fine).
1575 declare
1577 begin
1582 -- If this is an arithmetic operator and the result type is private,
1583 -- the operands and the result must be wrapped in conversion to
1584 -- expose the underlying numeric type and expand the proper checks,
1585 -- e.g. on division.
1589 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1590 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1599 else
1604 -------------------
1605 -- Operator_Kind --
1606 -------------------
1608 function Operator_Kind
1611 is
1614 begin
1615 -- Use CASE statement or array???
1652 else
1656 -- Unary operators
1658 else
1667 else
1675 ----------------------------
1676 -- Preanalyze_And_Resolve --
1677 ----------------------------
1682 begin
1686 -- We suppress all checks for this analysis, since the checks will
1687 -- be applied properly, and in the right location, when the default
1688 -- expression is reanalyzed and reexpanded later on.
1692 Expander_Mode_Restore;
1696 -- Version without context type
1701 begin
1708 Expander_Mode_Restore;
1712 ----------------------------------
1713 -- Replace_Actual_Discriminants --
1714 ----------------------------------
1721 -- Comment needed???
1723 -------------------
1724 -- Process_Discr --
1725 -------------------
1730 begin
1736 then
1752 -- Start of processing for Replace_Actual_Discriminants
1754 begin
1768 else
1773 -------------
1774 -- Resolve --
1775 -------------
1791 -- Determine whether a node comes from a predefined library unit or
1792 -- Standard.
1795 -- Try and fix up a literal so that it matches its expected type. New
1796 -- literals are manufactured if necessary to avoid cascaded errors.
1799 -- Return the current scope. Skip loop scopes created for the purpose of
1800 -- quantified expression analysis since those do not appear in the tree.
1803 -- Additional diagnostics when an ambiguous call has an ambiguous
1804 -- argument (typically a controlling actual).
1807 -- Called when attempt at resolving current expression fails
1809 ------------------------------------
1810 -- Comes_From_Predefined_Lib_Unit --
1811 -------------------------------------
1814 begin
1815 return
1817 or else Is_Predefined_File_Name
1821 --------------------
1822 -- Patch_Up_Value --
1823 --------------------
1826 begin
1843 then
1848 Char_Literal_Value =>
1864 --------------------------
1865 -- Proper_Current_Scope --
1866 --------------------------
1871 begin
1874 -- Skip a loop scope created for quantified expression analysis
1878 then
1880 else
1888 -------------------------------
1889 -- Report_Ambiguous_Argument --
1890 -------------------------------
1897 begin
1901 then
1904 -- Could use comments on what is going on here???
1912 else
1921 -----------------------
1922 -- Resolution_Failed --
1923 -----------------------
1926 begin
1932 -- The caller will return without calling the expander, so we need
1933 -- to set the analyzed flag. Note that it is fine to set Analyzed
1934 -- to True even if we are in the middle of a shallow analysis,
1935 -- (see the spec of sem for more details) since this is an error
1936 -- situation anyway, and there is no point in repeating the
1937 -- analysis later (indeed it won't work to repeat it later, since
1938 -- we haven't got a clear resolution of which entity is being
1939 -- referenced.)
1945 -- Start of processing for Resolve
1947 begin
1952 -- Access attribute on remote subprogram cannot be used for a non-remote
1953 -- access-to-subprogram type.
1964 then
1965 Error_Msg_N
1971 -- If the context is a Remote_Access_To_Subprogram, access attributes
1972 -- must be resolved with the corresponding fat pointer. There is no need
1973 -- to check for the attribute name since the return type of an
1974 -- attribute is never a remote type.
1979 then
1980 declare
1988 begin
1989 -- Check that Typ is a remote access-to-subprogram type
1993 -- Prefix (N) must statically denote a remote subprogram
1994 -- declared in a package specification.
1998 Attr = Attribute_Unrestricted_Access
1999 then
2014 or else
2016 then
2018 Error_Msg_N
2020 N);
2023 -- If we are generating code in distributed mode, perform
2024 -- semantic checks against corresponding remote entities.
2026 if Full_Expander_Active
2028 then
2029 Check_Subtype_Conformant
2031 Old_Id => Designated_Type
2057 then
2062 -- Return if already analyzed
2069 -- Return if type = Any_Type (previous error encountered)
2078 -- If not overloaded, then we know the type, and all that needs doing
2079 -- is to check that this type is compatible with the context.
2085 -- In the overloaded case, we must select the interpretation that
2086 -- is compatible with the context (i.e. the type passed to Resolve)
2088 else
2089 -- Loop through possible interpretations
2099 -- We are only interested in interpretations that are compatible
2100 -- with the expected type, any other interpretations are ignored.
2105 Write_Eol;
2108 else
2109 -- Skip the current interpretation if it is disabled by an
2110 -- abstract operator. This action is performed only when the
2111 -- type against which we are resolving is the same as the
2112 -- type of the interpretation.
2119 then
2127 -- First matching interpretation
2135 -- Matching interpretation that is not the first, maybe an
2136 -- error, but there are some cases where preference rules are
2137 -- used to choose between the two possibilities. These and
2138 -- some more obscure cases are handled in Disambiguate.
2140 else
2141 -- If the current statement is part of a predefined library
2142 -- unit, then all interpretations which come from user level
2143 -- packages should not be considered.
2145 if From_Lib
2147 then
2154 -- Disambiguation has succeeded. Skip the remaining
2155 -- interpretations.
2165 else
2166 -- Before we issue an ambiguity complaint, check for
2167 -- the case of a subprogram call where at least one
2168 -- of the arguments is Any_Type, and if so, suppress
2169 -- the message, since it is a cascaded error.
2172 declare
2176 begin
2188 Write_Eol;
2201 then
2206 then
2210 -- Not that special case, so issue message using the
2211 -- flag Ambiguous to control printing of the header
2212 -- message only at the start of an ambiguous set.
2217 then
2218 Error_Msg_N
2221 else
2222 Error_Msg_NE -- CODEFIX
2230 Error_Msg_N
2232 else
2233 Error_Msg_N -- CODEFIX
2239 then
2240 Report_Ambiguous_Argument;
2246 -- By default, the error message refers to the candidate
2247 -- interpretation. But if it is a predefined operator, it
2248 -- is implicitly declared at the declaration of the type
2249 -- of the operand. Recover the sloc of that declaration
2250 -- for the error message.
2256 Standard_Standard
2257 then
2262 then
2270 Standard_Standard
2271 then
2276 then
2280 -- If this is an indirect call, use the subprogram_type
2281 -- in the message, to have a meaningful location. Also
2282 -- indicate if this is an inherited operation, created
2283 -- by a type declaration.
2288 then
2290 Error_Msg_Sloc :=
2292 else
2299 then
2300 -- Special-case the message for universal_fixed
2301 -- operators, which are not declared with the type
2302 -- of the operand, but appear forever in Standard.
2306 then
2307 Error_Msg_N
2311 else
2312 Error_Msg_N
2316 elsif
2318 then
2319 Error_Msg_N
2321 else
2322 Error_Msg_N -- CODEFIX
2329 -- We have a matching interpretation, Expr_Type is the type
2330 -- from this interpretation, and Seen is the entity.
2332 -- For an operator, just set the entity name. The type will be
2333 -- set by the specific operator resolution routine.
2348 -- AI05-0139-2: Expression is overloaded because type has
2349 -- implicit dereference. If type matches context, no implicit
2350 -- dereference is involved.
2361 then
2364 -- For an explicit dereference, attribute reference, range,
2365 -- short-circuit form (which is not an operator node), or call
2366 -- with a name that is an explicit dereference, there is
2367 -- nothing to be done at this point.
2370 N_Attribute_Reference,
2371 N_And_Then,
2372 N_Indexed_Component,
2373 N_Or_Else,
2374 N_Range,
2375 N_Selected_Component,
2376 N_Slice)
2378 then
2381 -- For procedure or function calls, set the type of the name,
2382 -- and also the entity pointer for the prefix.
2386 then
2393 then
2398 -- For all other cases, just set the type of the Name
2400 else
2408 -- Move to next interpretation
2416 -- At this stage Found indicates whether or not an acceptable
2417 -- interpretation exists. If not, then we have an error, except that if
2418 -- the context is Any_Type as a result of some other error, then we
2419 -- suppress the error report.
2424 -- If type we are looking for is Void, then this is the procedure
2425 -- call case, and the error is simply that what we gave is not a
2426 -- procedure name (we think of procedure calls as expressions with
2427 -- types internally, but the user doesn't think of them this way!)
2431 -- Special case message if function used as a procedure
2436 then
2437 Error_Msg_NE
2441 -- Otherwise give general message (not clear what cases this
2442 -- covers, but no harm in providing for them!)
2444 else
2450 -- Otherwise we do have a subexpression with the wrong type
2452 -- Check for the case of an allocator which uses an access type
2453 -- instead of the designated type. This is a common error and we
2454 -- specialize the message, posting an error on the operand of the
2455 -- allocator, complaining that we expected the designated type of
2456 -- the allocator.
2462 then
2466 -- Check for view mismatch on Null in instances, for which the
2467 -- view-swapping mechanism has no identifier.
2473 then
2478 -- Check for an aggregate. Sometimes we can get bogus aggregates
2479 -- from misuse of parentheses, and we are about to complain about
2480 -- the aggregate without even looking inside it.
2482 -- Instead, if we have an aggregate of type Any_Composite, then
2483 -- analyze and resolve the component fields, and then only issue
2484 -- another message if we get no errors doing this (otherwise
2485 -- assume that the errors in the aggregate caused the problem).
2489 then
2490 -- Disable expansion in any case. If there is a type mismatch
2491 -- it may be fatal to try to expand the aggregate. The flag
2492 -- would otherwise be set to false when the error is posted.
2496 declare
2498 -- Check one aggregate, and set Found to True if we have a
2499 -- definite error in any of its elements
2502 -- Check one element of aggregate and set Found to True if
2503 -- we definitely have an error in the element.
2505 ----------------
2506 -- Check_Aggr --
2507 ----------------
2512 begin
2525 -- If this is a default-initialized component, then
2526 -- there is nothing to check. The box will be
2527 -- replaced by the appropriate call during late
2528 -- expansion.
2539 ----------------
2540 -- Check_Elmt --
2541 ----------------
2544 begin
2545 -- If we have a nested aggregate, go inside it (to
2546 -- attempt a naked analyze-resolve of the aggregate can
2547 -- cause undesirable cascaded errors). Do not resolve
2548 -- expression if it needs a type from context, as for
2549 -- integer * fixed expression.
2554 else
2559 then
2569 begin
2574 -- If an error message was issued already, Found got reset to
2575 -- True, so if it is still False, issue standard Wrong_Type msg.
2580 then
2581 declare
2583 begin
2589 -- Protected operation: retrieve operation name
2593 else
2603 declare
2607 begin
2614 Error_Msg_NE
2620 else
2624 else
2630 Resolution_Failed;
2633 -- Test if we have more than one interpretation for the context
2636 Resolution_Failed;
2639 -- Only one intepretation
2641 else
2642 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2643 -- the "+" on T is abstract, and the operands are of universal type,
2644 -- the above code will have (incorrectly) resolved the "+" to the
2645 -- universal one in Standard. Therefore check for this case and give
2646 -- an error. We can't do this earlier, because it would cause legal
2647 -- cases to get errors (when some other type has an abstract "+").
2653 then
2658 then
2659 Error_Msg_NE
2668 -- Here we have an acceptable interpretation for the context
2670 -- Propagate type information and normalize tree for various
2671 -- predefined operations. If the context only imposes a class of
2672 -- types, rather than a specific type, propagate the actual type
2673 -- downward.
2679 Typ = Any_Discrete
2680 then
2683 -- Any_Fixed is legal in a real context only if a specific fixed-
2684 -- point type is imposed. If Norman Cohen can be confused by this,
2685 -- it deserves a separate message.
2689 then
2696 -- A user-defined operator is transformed into a function call at
2697 -- this point, so that further processing knows that operators are
2698 -- really operators (i.e. are predefined operators). User-defined
2699 -- operators that are intrinsic are just renamings of the predefined
2700 -- ones, and need not be turned into calls either, but if they rename
2701 -- a different operator, we must transform the node accordingly.
2702 -- Instantiations of Unchecked_Conversion are intrinsic but are
2703 -- treated as functions, even if given an operator designator.
2708 then
2714 and then
2716 N_Subprogram_Renaming_Declaration
2717 then
2720 -- If the node is rewritten, it will be fully resolved in
2721 -- Rewrite_Renamed_Operator.
2731 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2733 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2735 when N_Short_Circuit
2736 => Resolve_Short_Circuit (N, Ctx_Type);
2738 when N_Attribute_Reference
2739 => Resolve_Attribute (N, Ctx_Type);
2741 when N_Case_Expression
2742 => Resolve_Case_Expression (N, Ctx_Type);
2744 when N_Character_Literal
2745 => Resolve_Character_Literal (N, Ctx_Type);
2747 when N_Expanded_Name
2748 => Resolve_Entity_Name (N, Ctx_Type);
2750 when N_Explicit_Dereference
2751 => Resolve_Explicit_Dereference (N, Ctx_Type);
2753 when N_Expression_With_Actions
2754 => Resolve_Expression_With_Actions (N, Ctx_Type);
2756 when N_Extension_Aggregate
2757 => Resolve_Extension_Aggregate (N, Ctx_Type);
2759 when N_Function_Call
2760 => Resolve_Call (N, Ctx_Type);
2762 when N_Identifier
2763 => Resolve_Entity_Name (N, Ctx_Type);
2765 when N_If_Expression
2766 => Resolve_If_Expression (N, Ctx_Type);
2768 when N_Indexed_Component
2769 => Resolve_Indexed_Component (N, Ctx_Type);
2771 when N_Integer_Literal
2772 => Resolve_Integer_Literal (N, Ctx_Type);
2774 when N_Membership_Test
2775 => Resolve_Membership_Op (N, Ctx_Type);
2777 when N_Null => Resolve_Null (N, Ctx_Type);
2779 when N_Op_And | N_Op_Or | N_Op_Xor
2780 => Resolve_Logical_Op (N, Ctx_Type);
2782 when N_Op_Eq | N_Op_Ne
2783 => Resolve_Equality_Op (N, Ctx_Type);
2785 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2786 => Resolve_Comparison_Op (N, Ctx_Type);
2788 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2790 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2791 N_Op_Divide | N_Op_Mod | N_Op_Rem
2793 => Resolve_Arithmetic_Op (N, Ctx_Type);
2795 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2797 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2799 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2800 => Resolve_Unary_Op (N, Ctx_Type);
2802 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2804 when N_Procedure_Call_Statement
2805 => Resolve_Call (N, Ctx_Type);
2807 when N_Operator_Symbol
2808 => Resolve_Operator_Symbol (N, Ctx_Type);
2810 when N_Qualified_Expression
2811 => Resolve_Qualified_Expression (N, Ctx_Type);
2813 when N_Quantified_Expression => null;
2815 when N_Raise_xxx_Error
2816 => Set_Etype (N, Ctx_Type);
2818 when N_Range => Resolve_Range (N, Ctx_Type);
2820 when N_Real_Literal
2821 => Resolve_Real_Literal (N, Ctx_Type);
2823 when N_Reference => Resolve_Reference (N, Ctx_Type);
2825 when N_Selected_Component
2826 => Resolve_Selected_Component (N, Ctx_Type);
2828 when N_Slice => Resolve_Slice (N, Ctx_Type);
2830 when N_String_Literal
2831 => Resolve_String_Literal (N, Ctx_Type);
2833 when N_Subprogram_Info
2834 => Resolve_Subprogram_Info (N, Ctx_Type);
2836 when N_Type_Conversion
2837 => Resolve_Type_Conversion (N, Ctx_Type);
2839 when N_Unchecked_Expression =>
2840 Resolve_Unchecked_Expression (N, Ctx_Type);
2842 when N_Unchecked_Type_Conversion =>
2843 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2844 end case;
2846 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2847 -- expression of an anonymous access type that occurs in the context
2848 -- of a named general access type, except when the expression is that
2849 -- of a membership test. This ensures proper legality checking in
2850 -- terms of allowed conversions (expressions that would be illegal to
2851 -- convert implicitly are allowed in membership tests).
2853 if Ada_Version >= Ada_2012
2854 and then Ekind (Ctx_Type) = E_General_Access_Type
2855 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2856 and then Nkind (Parent (N)) not in N_Membership_Test
2857 then
2858 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2859 Analyze_And_Resolve (N, Ctx_Type);
2860 end if;
2862 -- If the subexpression was replaced by a non-subexpression, then
2863 -- all we do is to expand it. The only legitimate case we know of
2864 -- is converting procedure call statement to entry call statements,
2865 -- but there may be others, so we are making this test general.
2867 if Nkind (N) not in N_Subexpr then
2868 Debug_A_Exit ("resolving ", N, " (done)");
2869 Expand (N);
2870 return;
2871 end if;
2873 -- AI05-144-2: Check dangerous order dependence within an expression
2874 -- that is not a subexpression. Exclude RHS of an assignment, because
2875 -- both sides may have side-effects and the check must be performed
2876 -- over the statement.
2878 if Nkind (Parent (N)) not in N_Subexpr
2879 and then Nkind (Parent (N)) /= N_Assignment_Statement
2880 and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
2881 then
2882 Check_Order_Dependence;
2883 end if;
2885 -- The expression is definitely NOT overloaded at this point, so
2886 -- we reset the Is_Overloaded flag to avoid any confusion when
2887 -- reanalyzing the node.
2889 Set_Is_Overloaded (N, False);
2891 -- Freeze expression type, entity if it is a name, and designated
2892 -- type if it is an allocator (RM 13.14(10,11,13)).
2894 -- Now that the resolution of the type of the node is complete, and
2895 -- we did not detect an error, we can expand this node. We skip the
2896 -- expand call if we are in a default expression, see section
2897 -- "Handling of Default Expressions" in Sem spec.
2899 Debug_A_Exit ("resolving ", N, " (done)");
2901 -- We unconditionally freeze the expression, even if we are in
2902 -- default expression mode (the Freeze_Expression routine tests this
2903 -- flag and only freezes static types if it is set).
2905 -- Ada 2012 (AI05-177): Expression functions do not freeze. Only
2906 -- their use (in an expanded call) freezes.
2908 if Ekind (Proper_Current_Scope) /= E_Function
2909 or else Nkind (Original_Node (Unit_Declaration_Node
2910 (Proper_Current_Scope))) /= N_Expression_Function
2911 then
2912 Freeze_Expression (N);
2913 end if;
2915 -- Now we can do the expansion
2917 Expand (N);
2918 end if;
2919 end Resolve;
2921 -------------
2922 -- Resolve --
2923 -------------
2925 -- Version with check(s) suppressed
2927 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2928 begin
2929 if Suppress = All_Checks then
2930 declare
2931 Svg : constant Suppress_Record := Scope_Suppress;
2932 begin
2933 Scope_Suppress := Suppress_All;
2934 Resolve (N, Typ);
2935 Scope_Suppress := Svg;
2936 end;
2938 else
2939 declare
2940 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
2941 begin
2942 Scope_Suppress.Suppress (Suppress) := True;
2943 Resolve (N, Typ);
2944 Scope_Suppress.Suppress (Suppress) := Svg;
2945 end;
2946 end if;
2947 end Resolve;
2949 -------------
2950 -- Resolve --
2951 -------------
2953 -- Version with implicit type
2955 procedure Resolve (N : Node_Id) is
2956 begin
2957 Resolve (N, Etype (N));
2958 end Resolve;
2960 ---------------------
2961 -- Resolve_Actuals --
2962 ---------------------
2964 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2965 Loc : constant Source_Ptr := Sloc (N);
2966 A : Node_Id;
2967 F : Entity_Id;
2968 A_Typ : Entity_Id;
2969 F_Typ : Entity_Id;
2970 Prev : Node_Id := Empty;
2971 Orig_A : Node_Id;
2973 procedure Check_Argument_Order;
2974 -- Performs a check for the case where the actuals are all simple
2975 -- identifiers that correspond to the formal names, but in the wrong
2976 -- order, which is considered suspicious and cause for a warning.
2978 procedure Check_Prefixed_Call;
2979 -- If the original node is an overloaded call in prefix notation,
2981 -- Try_Object_Operation has already verified that there is a valid
2982 -- interpretation, but the form of the actual can only be determined
2983 -- once the primitive operation is identified.
2986 -- If the actual is missing in a call, insert in the actuals list
2987 -- an instance of the default expression. The insertion is always
2988 -- a named association.
2991 -- Check whether T1 and T2, or their full views, are derived from a
2992 -- common type. Used to enforce the restrictions on array conversions
2993 -- of AI95-00246.
2996 -- Predicate to determine whether an actual that is a concatenation
2997 -- will be evaluated statically and does not need a transient scope.
2998 -- This must be determined before the actual is resolved and expanded
2999 -- because if needed the transient scope must be introduced earlier.
3001 --------------------------
3002 -- Check_Argument_Order --
3003 --------------------------
3006 begin
3007 -- Nothing to do if no parameters, or original node is neither a
3008 -- function call nor a procedure call statement (happens in the
3009 -- operator-transformed-to-function call case), or the call does
3010 -- not come from source, or this warning is off.
3012 if not Warn_On_Parameter_Order
3016 then
3020 declare
3023 begin
3024 -- Nothing to do if only one parameter
3030 -- Here if at least two arguments
3032 declare
3038 -- Set True if an out of order case is found
3040 begin
3041 -- Collect identifier names of actuals, fail if any actual is
3042 -- not a simple identifier, and record max length of name.
3048 else
3054 -- If we got this far, all actuals are identifiers and the list
3055 -- of their names is stored in the Actuals array.
3060 -- If we ran out of formals, that's odd, probably an error
3061 -- which will be detected elsewhere, but abandon the search.
3067 -- If name matches and is in order OK
3072 else
3073 -- If no match, see if it is elsewhere in list and if so
3074 -- flag potential wrong order if type is compatible.
3078 and then
3080 then
3086 -- No match
3094 -- If Formals left over, also probably an error, skip warning
3100 -- Here we give the warning if something was out of order
3103 Error_Msg_N
3110 -------------------------
3111 -- Check_Prefixed_Call --
3112 -------------------------
3121 begin
3122 -- Check whether the call is a prefixed call, with or without
3123 -- additional actuals.
3126 or else
3132 then
3135 then
3136 -- Introduce dereference on object in prefix
3138 New_A :=
3146 then
3147 -- Introduce an implicit 'Access in prefix
3150 Error_Msg_NE
3166 --------------------
3167 -- Insert_Default --
3168 --------------------
3174 begin
3175 -- Missing argument in call, nothing to insert
3180 else
3181 -- Note that we do a full New_Copy_Tree, so that any associated
3182 -- Itypes are properly copied. This may not be needed any more,
3183 -- but it does no harm as a safety measure! Defaults of a generic
3184 -- formal may be out of bounds of the corresponding actual (see
3185 -- cc1311b) and an additional check may be required.
3187 Actval :=
3188 New_Copy_Tree
3195 then
3201 then
3204 then
3205 -- If default is a real literal, do not introduce a
3206 -- conversion whose effect may depend on the run-time
3207 -- size of universal real.
3211 else
3222 -- Resolve aggregates with their base type, to avoid scope
3223 -- anomalies: the subtype was first built in the subprogram
3224 -- declaration, and the current call may be nested.
3228 else
3232 else
3235 -- See note above concerning aggregates
3239 then
3242 -- Resolve entities with their own type, which may differ from
3243 -- the type of a reference in a generic context (the view
3244 -- swapping mechanism did not anticipate the re-analysis of
3245 -- default values in calls).
3250 else
3255 -- If default is a tag indeterminate function call, propagate tag
3256 -- to obtain proper dispatching.
3260 then
3266 -- If the default expression raises constraint error, then just
3267 -- silently replace it with an N_Raise_Constraint_Error node, since
3268 -- we already gave the warning on the subprogram spec. If node is
3269 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3270 -- the warnings removal machinery.
3274 then
3282 Assoc :=
3287 -- Case of insertion is first named actual
3291 then
3298 else
3302 else
3306 -- Case of insertion is not first named actual
3308 else
3309 Set_Next_Named_Actual
3321 -------------------
3322 -- Same_Ancestor --
3323 -------------------
3329 begin
3332 then
3338 then
3345 --------------------------
3346 -- Static_Concatenation --
3347 --------------------------
3350 begin
3357 -- Concatenation is static when both operands are static and
3358 -- the concatenation operator is a predefined one.
3361 and then
3363 and then
3368 declare
3370 begin
3373 and then
3377 else
3383 -- Start of processing for Resolve_Actuals
3385 begin
3386 Check_Argument_Order;
3389 Check_Prefixed_Call;
3398 -- If we have an error in any actual or formal, indicated by a type
3399 -- of Any_Type, then abandon resolution attempt, and set result type
3400 -- to Any_Type.
3404 then
3409 -- Case where actual is present
3411 -- If the actual is an entity, generate a reference to it now. We
3412 -- do this before the actual is resolved, because a formal of some
3413 -- protected subprogram, or a task discriminant, will be rewritten
3414 -- during expansion, and the source entity reference may be lost.
3419 then
3425 then
3437 then
3438 -- If style checking mode on, check match of formal name
3446 -- If the formal is Out or In_Out, do not resolve and expand the
3447 -- conversion, because it is subsequently expanded into explicit
3448 -- temporaries and assignments. However, the object of the
3449 -- conversion can be resolved. An exception is the case of tagged
3450 -- type conversion with a class-wide actual. In that case we want
3451 -- the tag check to occur and no temporary will be needed (no
3452 -- representation change can occur) and the parameter is passed by
3453 -- reference, so we go ahead and resolve the type conversion.
3454 -- Another exception is the case of reference to component or
3455 -- subcomponent of a bit-packed array, in which case we want to
3456 -- defer expansion to the point the in and out assignments are
3457 -- performed.
3462 then
3465 then
3466 -- In a view conversion, the conversion must be legal in
3467 -- both directions, and thus both component types must be
3468 -- aliased, or neither (4.6 (8)).
3470 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3471 -- the privacy requirement should not apply to generic
3472 -- types, and should be checked in an instance. ARG query
3473 -- is in order ???
3477 then
3478 Error_Msg_N
3482 -- Comment here??? what set of cases???
3484 elsif
3486 then
3487 -- Check view conv between unrelated by ref array types
3491 then
3492 Error_Msg_N
3496 -- In Ada 2005 mode, check view conversion component
3497 -- type cannot be private, tagged, or volatile. Note
3498 -- that we only apply this to source conversions. The
3499 -- generated code can contain conversions which are
3500 -- not subject to this test, and we cannot extract the
3501 -- component type in such cases since it is not present.
3505 then
3506 declare
3508 Component_Type
3510 begin
3515 then
3516 Error_Msg_N
3527 -- Resolve expression if conversion is all OK
3532 then
3536 -- If the actual is a function call that returns a limited
3537 -- unconstrained object that needs finalization, create a
3538 -- transient scope for it, so that it can receive the proper
3539 -- finalization list.
3544 and then Full_Expander_Active
3546 then
3550 -- A small optimization: if one of the actuals is a concatenation
3551 -- create a block around a procedure call to recover stack space.
3552 -- This alleviates stack usage when several procedure calls in
3553 -- the same statement list use concatenation. We do not perform
3554 -- this wrapping for code statements, where the argument is a
3555 -- static string, and we want to preserve warnings involving
3556 -- sequences of such statements.
3560 and then Full_Expander_Active
3561 and then
3565 then
3569 else
3573 and then
3576 then
3577 Error_Msg_N
3590 -- (Ada 2005: AI-251): If the actual is an allocator whose
3591 -- directly designated type is a class-wide interface, we build
3592 -- an anonymous access type to use it as the type of the
3593 -- allocator. Later, when the subprogram call is expanded, if
3594 -- the interface has a secondary dispatch table the expander
3595 -- will add a type conversion to force the correct displacement
3596 -- of the pointer.
3599 declare
3605 begin
3608 then
3616 -- Ada 2005, AI-162:If the actual is an allocator, the
3617 -- innermost enclosing statement is the master of the
3618 -- created object. This needs to be done with expansion
3619 -- enabled only, otherwise the transient scope will not
3620 -- be removed in the expansion of the wrapped construct.
3623 and then Full_Expander_Active
3624 then
3630 -- (Ada 2005): The call may be to a primitive operation of
3631 -- a tagged synchronized type, declared outside of the type.
3632 -- In this case the controlling actual must be converted to
3633 -- its corresponding record type, which is the formal type.
3634 -- The actual may be a subtype, either because of a constraint
3635 -- or because it is a generic actual, so use base type to
3636 -- locate concurrent type.
3643 then
3644 -- If the actual is overloaded, look for an interpretation
3645 -- that has a synchronized type.
3650 else
3651 declare
3655 begin
3660 then
3670 declare
3673 begin
3676 else
3680 -- Tagged synchronized type (case 1): the actual is a
3681 -- concurrent type.
3685 then
3687 Unchecked_Convert_To
3691 -- Tagged synchronized type (case 2): the formal is a
3692 -- concurrent type.
3695 and then Present
3700 then
3703 -- Common case
3705 else
3709 else
3711 -- not a synchronized operation.
3722 N_Procedure_Call_Statement)
3723 then
3724 -- In formal mode, check that actual parameters matching
3725 -- formals of tagged types are objects (or ancestor type
3726 -- conversions of objects), not general expressions.
3733 declare
3738 begin
3740 Check_SPARK_Restriction
3743 -- In formal mode, the only view conversions are those
3744 -- involving ancestor conversion of an extended type.
3746 elsif not
3752 then
3753 if Ekind_In
3755 then
3756 Check_SPARK_Restriction
3759 else
3760 Check_SPARK_Restriction
3764 else
3769 else
3773 -- In formal mode, the only view conversions are those
3774 -- involving ancestor conversion of an extended type.
3778 then
3779 Check_SPARK_Restriction
3785 -- Save actual for subsequent check on order dependence, and
3786 -- indicate whether actual is modifiable. For AI05-0144-2.
3788 -- If this is a call to a reference function that is the result
3789 -- of expansion, as in element iterator loops, this does not lead
3790 -- to a dangerous order dependence: only subsequent use of the
3791 -- denoted element might, in some enclosing call.
3795 then
3799 -- For mode IN, if actual is an entity, and the type of the formal
3800 -- has warnings suppressed, then we reset Never_Set_In_Source for
3801 -- the calling entity. The reason for this is to catch cases like
3802 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3803 -- uses trickery to modify an IN parameter.
3810 then
3814 -- Perform error checks for IN and IN OUT parameters
3818 -- Check unset reference. For scalar parameters, it is clearly
3819 -- wrong to pass an uninitialized value as either an IN or
3820 -- IN-OUT parameter. For composites, it is also clearly an
3821 -- error to pass a completely uninitialized value as an IN
3822 -- parameter, but the case of IN OUT is trickier. We prefer
3823 -- not to give a warning here. For example, suppose there is
3824 -- a routine that sets some component of a record to False.
3825 -- It is perfectly reasonable to make this IN-OUT and allow
3826 -- either initialized or uninitialized records to be passed
3827 -- in this case.
3829 -- For partially initialized composite values, we also avoid
3830 -- warnings, since it is quite likely that we are passing a
3831 -- partially initialized value and only the initialized fields
3832 -- will in fact be read in the subprogram.
3837 then
3841 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3842 -- actual to a nested call, since this is case of reading an
3843 -- out parameter, which is not allowed.
3848 then
3853 -- Case of OUT or IN OUT parameter
3857 -- For an Out parameter, check for useless assignment. Note
3858 -- that we can't set Last_Assignment this early, because we may
3859 -- kill current values in Resolve_Call, and that call would
3860 -- clobber the Last_Assignment field.
3862 -- Note: call Warn_On_Useless_Assignment before doing the check
3863 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3864 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3865 -- reflects the last assignment, not this one!
3872 then
3877 -- Validate the form of the actual. Note that the call to
3878 -- Is_OK_Variable_For_Out_Formal generates the required
3879 -- reference in this case.
3881 -- A call to an initialization procedure for an aggregate
3882 -- component may initialize a nested component of a constant
3883 -- designated object. In this context the object is variable.
3887 then
3891 -- What's the following about???
3895 else
3896 Kill_All_Checks;
3905 -- Apply appropriate range checks for in, out, and in-out
3906 -- parameters. Out and in-out parameters also need a separate
3907 -- check, if there is a type conversion, to make sure the return
3908 -- value meets the constraints of the variable before the
3909 -- conversion.
3911 -- Gigi looks at the check flag and uses the appropriate types.
3912 -- For now since one flag is used there is an optimization which
3913 -- might not be done in the In Out case since Gigi does not do
3914 -- any analysis. More thought required about this ???
3918 -- Apply predicate checks, unless this is a call to the
3919 -- predicate check function itself, which would cause an
3920 -- infinite recursion.
3924 then
3928 -- Apply required constraint checks
3941 then
3947 then
3953 then
3956 else
3960 -- Ada 2005 (AI-231): Note that the controlling parameter case
3961 -- already existed in Ada 95, which is partially checked
3962 -- elsewhere (see Checks), and we don't want the warning
3963 -- message to differ.
3968 then
3970 Apply_Compile_Time_Constraint_Error
3976 Apply_Compile_Time_Constraint_Error
3988 Apply_Scalar_Range_Check
3990 else
3991 Apply_Range_Check
3995 else
4000 then
4002 else
4008 -- An actual associated with an access parameter is implicitly
4009 -- converted to the anonymous access type of the formal and must
4010 -- satisfy the legality checks for access conversions.
4014 Error_Msg_N
4018 -- If the actual is an access selected component of a variable,
4019 -- the call may modify its designated object. It is reasonable
4020 -- to treat this as a potential modification of the enclosing
4021 -- record, to prevent spurious warnings that it should be
4022 -- declared as a constant, because intuitively programmers
4023 -- regard the designated subcomponent as part of the record.
4028 then
4033 -- Check bad case of atomic/volatile argument (RM C.6(12))
4037 then
4040 then
4041 Error_Msg_NE
4047 then
4048 Error_Msg_NE
4054 -- Check that subprograms don't have improper controlling
4055 -- arguments (RM 3.9.2 (9)).
4057 -- A primitive operation may have an access parameter of an
4058 -- incomplete tagged type, but a dispatching call is illegal
4059 -- if the type is still incomplete.
4065 declare
4067 begin
4071 then
4072 Error_Msg_NE
4086 then
4091 then
4093 Error_Msg_NE
4097 -- Apply the checks described in 3.10.2(27): if the context is a
4098 -- specific access-to-object, the actual cannot be class-wide.
4099 -- Use base type to exclude access_to_subprogram cases.
4106 and then
4111 -- Disable these checks for call to imported C++ subprograms
4113 and then not
4117 then
4118 Error_Msg_N
4123 Error_Msg_NE
4130 -- If it is a named association, treat the selector_name as a
4131 -- proper identifier, and mark the corresponding entity. Ignore
4132 -- this reference in Alfa mode, as it refers to an entity not in
4133 -- scope at the point of reference, so the reference should be
4134 -- ignored for computing effects of subprograms.
4137 and then not Alfa_Mode
4138 then
4153 -- Case where actual is not present
4155 else
4156 Insert_Default;
4163 -----------------------
4164 -- Resolve_Allocator --
4165 -----------------------
4177 procedure Check_Allocator_Discrim_Accessibility
4180 -- Check that accessibility level associated with an access discriminant
4181 -- initialized in an allocator by the expression Disc_Exp is not deeper
4182 -- than the level of the allocator type Alloc_Typ. An error message is
4183 -- issued if this condition is violated. Specialized checks are done for
4184 -- the cases of a constraint expression which is an access attribute or
4185 -- an access discriminant.
4188 -- If the allocator is an actual in a call, it is allowed to be class-
4189 -- wide when the context is not because it is a controlling actual.
4191 -------------------------------------------
4192 -- Check_Allocator_Discrim_Accessibility --
4193 -------------------------------------------
4195 procedure Check_Allocator_Discrim_Accessibility
4198 is
4199 begin
4202 then
4203 Error_Msg_N
4206 -- When the expression is an Access attribute the level of the prefix
4207 -- object must not be deeper than that of the allocator's type.
4211 Attribute_Access
4214 then
4215 Error_Msg_N
4217 Disc_Exp);
4219 -- When the expression is an access discriminant the check is against
4220 -- the level of the prefix object.
4226 then
4227 Error_Msg_N
4229 Disc_Exp);
4231 -- All other cases are legal
4233 else
4238 ----------------------------
4239 -- In_Dispatching_Context --
4240 ----------------------------
4245 begin
4251 -- Start of processing for Resolve_Allocator
4253 begin
4254 -- Replace general access with specific type
4264 -- For qualified expression, resolve the expression using the
4265 -- given subtype (nothing to do for type mark, subtype indication)
4270 and then not In_Dispatching_Context
4271 then
4272 Error_Msg_N
4279 -- A qualified expression requires an exact match of the type,
4280 -- class-wide matching is not allowed.
4285 then
4289 -- Calls to build-in-place functions are not currently supported in
4290 -- allocators for access types associated with a simple storage pool.
4291 -- Supporting such allocators may require passing additional implicit
4292 -- parameters to build-in-place functions (or a significant revision
4293 -- of the current b-i-p implementation to unify the handling for
4294 -- multiple kinds of storage pools). ???
4298 then
4299 declare
4302 begin
4304 and then
4305 Present (Get_Rep_Pragma
4307 then
4308 Error_Msg_N
4315 -- A special accessibility check is needed for allocators that
4316 -- constrain access discriminants. The level of the type of the
4317 -- expression used to constrain an access discriminant cannot be
4318 -- deeper than the type of the allocator (in contrast to access
4319 -- parameters, where the level of the actual can be arbitrary).
4321 -- We can't use Valid_Conversion to perform this check because
4322 -- in general the type of the allocator is unrelated to the type
4323 -- of the access discriminant.
4327 then
4334 then
4337 -- Get the first component expression of the aggregate
4347 else
4351 else
4370 else
4375 else
4384 -- For a subtype mark or subtype indication, freeze the subtype
4386 else
4390 Error_Msg_N
4394 -- A special accessibility check is needed for allocators that
4395 -- constrain access discriminants. The level of the type of the
4396 -- expression used to constrain an access discriminant cannot be
4397 -- deeper than the type of the allocator (in contrast to access
4398 -- parameters, where the level of the actual can be arbitrary).
4399 -- We can't use Valid_Conversion to perform this check because
4400 -- in general the type of the allocator is unrelated to the type
4401 -- of the access discriminant.
4406 then
4416 else
4430 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4431 -- check that the level of the type of the created object is not deeper
4432 -- than the level of the allocator's access type, since extensions can
4433 -- now occur at deeper levels than their ancestor types. This is a
4434 -- static accessibility level check; a run-time check is also needed in
4435 -- the case of an initialized allocator with a class-wide argument (see
4436 -- Expand_Allocator_Expression).
4440 then
4441 declare
4444 begin
4449 else
4455 then
4460 E);
4466 -- Do not apply Ada 2005 accessibility checks on a class-wide
4467 -- allocator if the type given in the allocator is a formal
4468 -- type. A run-time check will be performed in the instance.
4478 -- Check for allocation from an empty storage pool
4483 -- If the context is an unchecked conversion, as may happen within an
4484 -- inlined subprogram, the allocator is being resolved with its own
4485 -- anonymous type. In that case, if the target type has a specific
4486 -- storage pool, it must be inherited explicitly by the allocator type.
4490 then
4491 Set_Associated_Storage_Pool
4499 -- Check that an allocator with task parts isn't for a nested access
4500 -- type when restriction No_Task_Hierarchy applies.
4504 then
4508 -- An erroneous allocator may be rewritten as a raise Program_Error
4509 -- statement.
4513 -- An anonymous access discriminant is the definition of a
4514 -- coextension.
4518 N_Discriminant_Specification
4519 then
4520 declare
4524 begin
4525 -- Ada 2012 AI05-0052: If the designated type of the allocator
4526 -- is limited, then the allocator shall not be used to define
4527 -- the value of an access discriminant unless the discriminated
4528 -- type is immutably limited.
4533 then
4534 Error_Msg_N
4540 -- Avoid marking an allocator as a dynamic coextension if it is
4541 -- within a static construct.
4547 -- Cleanup for potential static coextensions
4549 else
4555 -- Report a simple error: if the designated object is a local task,
4556 -- its body has not been seen yet, and its activation will fail an
4557 -- elaboration check.
4564 then
4569 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4570 -- type with a task component on a subpool. This action must raise
4571 -- Program_Error at runtime.
4577 then
4588 ---------------------------
4589 -- Resolve_Arithmetic_Op --
4590 ---------------------------
4592 -- Used for resolving all arithmetic operators except exponentiation
4603 -- We do the resolution using the base type, because intermediate values
4604 -- in expressions always are of the base type, not a subtype of it.
4607 -- Returns True if N is in a context that expects "any real type"
4610 -- Return True iff given type is Integer or universal real/integer
4613 -- Choose type of integer literal in fixed-point operation to conform
4614 -- to available fixed-point type. T is the type of the other operand,
4615 -- which is needed to determine the expected type of N.
4618 -- Set operand type to T if universal
4620 -------------------------------
4621 -- Expected_Type_Is_Any_Real --
4622 -------------------------------
4625 begin
4626 -- N is the expression after "delta" in a fixed_point_definition;
4627 -- see RM-3.5.9(6):
4630 N_Decimal_Fixed_Point_Definition,
4632 -- N is one of the bounds in a real_range_specification;
4633 -- see RM-3.5.7(5):
4635 N_Real_Range_Specification,
4637 -- N is the expression of a delta_constraint;
4638 -- see RM-J.3(3):
4640 N_Delta_Constraint);
4643 -----------------------------
4644 -- Is_Integer_Or_Universal --
4645 -----------------------------
4652 begin
4658 else
4664 then
4675 ----------------------------
4676 -- Set_Mixed_Mode_Operand --
4677 ----------------------------
4683 begin
4686 -- A universal integer literal is resolved as standard integer
4687 -- except in the case of a fixed-point result, where we leave it
4688 -- as universal (to be handled by Exp_Fixd later on)
4692 else
4700 then
4701 -- A universal real can appear in a fixed-type context. We resolve
4702 -- the literal with that context, even though this might raise an
4703 -- exception prematurely (the other operand may be zero).
4710 then
4711 -- Integer arg in mixed-mode operation. Resolve with universal
4712 -- type, in case preference rule must be applied.
4718 then
4719 -- Not a mixed-mode operation, resolve with context
4725 -- N may itself be a mixed-mode operation, so use context type
4732 then
4733 -- Must be (fixed * fixed) operation, operand must have one
4734 -- compatible interpretation.
4742 then
4743 -- C * F(X) in a fixed context, where C is a real literal or a
4744 -- fixed-point expression. F must have either a fixed type
4745 -- interpretation or an integer interpretation, but not both.
4752 else
4759 else
4767 -- Reanalyze the literal with the fixed type of the context. If
4768 -- context is Universal_Fixed, we are within a conversion, leave
4769 -- the literal as a universal real because there is no usable
4770 -- fixed type, and the target of the conversion plays no role in
4771 -- the resolution.
4773 declare
4777 begin
4780 else
4786 then
4788 else
4796 else
4801 ----------------------
4802 -- Set_Operand_Type --
4803 ----------------------
4806 begin
4809 then
4814 -- Start of processing for Resolve_Arithmetic_Op
4816 begin
4821 then
4825 -- Special-case for mixed-mode universal expressions or fixed point type
4826 -- operation: each argument is resolved separately. The same treatment
4827 -- is required if one of the operands of a fixed point operation is
4828 -- universal real, since in this case we don't do a conversion to a
4829 -- specific fixed-point type (instead the expander handles the case).
4831 -- Set the type of the node to its universal interpretation because
4832 -- legality checks on an exponentiation operand need the context.
4837 then
4848 or else
4851 then
4856 -- If context is a fixed type and one operand is integer, the other
4857 -- is resolved with the type of the context.
4862 then
4869 then
4873 else
4878 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4879 -- multiplying operators from being used when the expected type is
4880 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4881 -- some cases where the expected type is actually Any_Real;
4882 -- Expected_Type_Is_Any_Real takes care of that case.
4886 then
4890 N_Unchecked_Type_Conversion)
4891 then
4898 else
4901 and then not
4903 N_Unchecked_Type_Conversion)
4904 then
4905 Error_Msg_N
4910 -- The expected type is "any real type" in contexts like
4912 -- type T is delta <universal_fixed-expression> ...
4914 -- in which case we need to set the type to Universal_Real
4915 -- so that static expression evaluation will work properly.
4919 else
4929 then
4934 -- If no previous errors, this is only possible if one operand is
4935 -- overloaded and the context is universal. Resolve as such.
4940 else
4942 and then
4944 then
4948 -- If the context is Universal_Fixed and the operands are also
4949 -- universal fixed, this is an error, unless there is only one
4950 -- applicable fixed_point type (usually Duration).
4958 else
4963 else
4968 -- If one of the arguments was resolved to a non-universal type.
4969 -- label the result of the operation itself with the same type.
4970 -- Do the same for the universal argument, if any.
4982 -- In SPARK, a multiplication or division with operands of fixed point
4983 -- types shall be qualified or explicitly converted to identify the
4984 -- result type.
4989 and then
4991 then
4992 Check_SPARK_Restriction
4996 -- Set overflow and division checking bit
5003 -- Give warning if explicit division by zero
5007 then
5013 or else
5016 then
5017 -- Specialize the warning message according to the operation.
5018 -- The following warnings are for the case
5023 -- For division, we have two cases, for float division
5024 -- of an unconstrained float type, on a machine where
5025 -- Machine_Overflows is false, we don't get an exception
5026 -- at run-time, but rather an infinity or Nan. The Nan
5027 -- case is pretty obscure, so just warn about infinities.
5031 and then not Machine_Overflows_On_Target
5032 then
5033 Error_Msg_N
5037 -- For all other cases, we get a Constraint_Error
5039 else
5040 Apply_Compile_Time_Constraint_Error
5046 Apply_Compile_Time_Constraint_Error
5051 Apply_Compile_Time_Constraint_Error
5055 -- Division by zero can only happen with division, rem,
5056 -- and mod operations.
5062 -- Otherwise just set the flag to check at run time
5064 else
5069 -- If Restriction No_Implicit_Conditionals is active, then it is
5070 -- violated if either operand can be negative for mod, or for rem
5071 -- if both operands can be negative.
5075 then
5076 declare
5083 -- Set if corresponding operand might be negative
5085 begin
5086 Determine_Range
5090 Determine_Range
5094 -- Check if we will be generating conditionals. There are two
5095 -- cases where that can happen, first for REM, the only case
5096 -- is largest negative integer mod -1, where the division can
5097 -- overflow, but we still have to give the right result. The
5098 -- front end generates a test for this annoying case. Here we
5099 -- just test if both operands can be negative (that's what the
5100 -- expander does, so we match its logic here).
5102 -- The second case is mod where either operand can be negative.
5103 -- In this case, the back end has to generate additional tests.
5106 or else
5108 then
5119 ------------------
5120 -- Resolve_Call --
5121 ------------------
5133 function Same_Or_Aliased_Subprograms
5136 -- Returns True if the subprogram entity S is the same as E or else
5137 -- S is an alias of E.
5139 ---------------------------------
5140 -- Same_Or_Aliased_Subprograms --
5141 ---------------------------------
5143 function Same_Or_Aliased_Subprograms
5146 is
5148 begin
5153 -- Start of processing for Resolve_Call
5155 begin
5156 -- The context imposes a unique interpretation with type Typ on a
5157 -- procedure or function call. Find the entity of the subprogram that
5158 -- yields the expected type, and propagate the corresponding formal
5159 -- constraints on the actuals. The caller has established that an
5160 -- interpretation exists, and emitted an error if not unique.
5162 -- First deal with the case of a call to an access-to-subprogram,
5163 -- dereference made explicit in Analyze_Call.
5169 else
5170 -- Find the interpretation whose type (a subprogram type) has a
5171 -- return type that is compatible with the context. Analysis of
5172 -- the node has established that one exists.
5191 -- If the prefix is not an entity, then resolve it
5197 -- For an indirect call, we always invalidate checks, since we do not
5198 -- know whether the subprogram is local or global. Yes we could do
5199 -- better here, e.g. by knowing that there are no local subprograms,
5200 -- but it does not seem worth the effort. Similarly, we kill all
5201 -- knowledge of current constant values.
5203 Kill_Current_Values;
5205 -- If this is a procedure call which is really an entry call, do
5206 -- the conversion of the procedure call to an entry call. Protected
5207 -- operations use the same circuitry because the name in the call
5208 -- can be an arbitrary expression with special resolution rules.
5213 then
5217 -- Kill checks and constant values, as above for indirect case
5218 -- Who knows what happens when another task is activated?
5220 Kill_Current_Values;
5223 -- Normal subprogram call with name established in Resolve
5229 -- Otherwise we must have the case of an overloaded call
5231 else
5234 -- Initialize Nam to prevent warning (we know it will be assigned
5235 -- in the loop below, but the compiler does not know that).
5255 then
5256 -- The prefix is a parameterless function call that returns an access
5257 -- to subprogram. If parameters are present in the current call, add
5258 -- add an explicit dereference. We use the base type here because
5259 -- within an instance these may be subtypes.
5261 -- The dereference is added either in Analyze_Call or here. Should
5262 -- be consolidated ???
5271 -- Check that a call to Current_Task does not occur in an entry body
5274 declare
5277 begin
5279 loop
5282 -- Exclude calls that occur within the default of a formal
5283 -- parameter of the entry, since those are evaluated outside
5284 -- of the body.
5291 then
5293 Error_Msg_NE
5296 Error_Msg_NE
5308 -- Check that a procedure call does not occur in the context of the
5309 -- entry call statement of a conditional or timed entry call. Note that
5310 -- the case of a call to a subprogram renaming of an entry will also be
5311 -- rejected. The test for N not being an N_Entry_Call_Statement is
5312 -- defensive, covering the possibility that the processing of entry
5313 -- calls might reach this point due to later modifications of the code
5314 -- above.
5319 then
5323 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5324 -- for a procedure_or_entry_call, the procedure_name or
5325 -- procedure_prefix of the procedure_call_statement shall denote
5326 -- an entry renamed by a procedure, or (a view of) a primitive
5327 -- subprogram of a limited interface whose first parameter is
5328 -- a controlling parameter.
5333 then
5334 Error_Msg_N
5339 -- Check that this is not a call to a protected procedure or entry from
5340 -- within a protected function.
5344 -- Freeze the subprogram name if not in a spec-expression. Note that we
5345 -- freeze procedure calls as well as function calls. Procedure calls are
5346 -- not frozen according to the rules (RM 13.14(14)) because it is
5347 -- impossible to have a procedure call to a non-frozen procedure in pure
5348 -- Ada, but in the code that we generate in the expander, this rule
5349 -- needs extending because we can generate procedure calls that need
5350 -- freezing.
5352 -- In Ada 2012, expression functions may be called within pre/post
5353 -- conditions of subsequent functions or expression functions. Such
5354 -- calls do not freeze when they appear within generated bodies, which
5355 -- would place the freeze node in the wrong scope. An expression
5356 -- function is frozen in the usual fashion, by the appearance of a real
5357 -- body, or at the end of a declarative part.
5360 and then
5363 then
5367 -- For a predefined operator, the type of the result is the type imposed
5368 -- by context, except for a predefined operation on universal fixed.
5369 -- Otherwise The type of the call is the type returned by the subprogram
5370 -- being called.
5377 -- If the subprogram returns an array type, and the context requires the
5378 -- component type of that array type, the node is really an indexing of
5379 -- the parameterless call. Resolve as such. A pathological case occurs
5380 -- when the type of the component is an access to the array type. In
5381 -- this case the call is truly ambiguous.
5384 and then
5389 and then
5390 Covers
5393 then
5394 declare
5399 begin
5402 then
5403 Error_Msg_N
5405 else
5411 or else
5413 and then
5415 then
5418 -- Indexed call to a parameterless function
5420 Index_Node :=
5422 Prefix =>
5426 else
5427 -- An Ada 2005 prefixed call to a primitive operation
5428 -- whose first parameter is the prefix. This prefix was
5429 -- prepended to the parameter list, which is actually a
5430 -- list of indexes. Remove the prefix in order to build
5431 -- the proper indexed component.
5433 Index_Node :=
5435 Prefix =>
5438 Parameter_Associations =>
5439 New_List
5444 -- Preserve the parenthesis count of the node
5448 -- Since we are correcting a node classification error made
5449 -- by the parser, we call Replace rather than Rewrite.
5463 else
5467 -- In the case where the call is to an overloaded subprogram, Analyze
5468 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5469 -- such a case Normalize_Actuals needs to be called once more to order
5470 -- the actuals correctly. Otherwise the call will have the ordering
5471 -- given by the last overloaded subprogram whether this is the correct
5472 -- one being called or not.
5479 -- In any case, call is fully resolved now. Reset Overload flag, to
5480 -- prevent subsequent overload resolution if node is analyzed again
5485 -- If we are calling the current subprogram from immediately within its
5486 -- body, then that is the case where we can sometimes detect cases of
5487 -- infinite recursion statically. Do not try this in case restriction
5488 -- No_Recursion is in effect anyway, and do it only for source calls.
5493 -- Issue warning for possible infinite recursion in the absence
5494 -- of the No_Recursion restriction.
5499 then
5500 -- Here we detected and flagged an infinite recursion, so we do
5501 -- not need to test the case below for further warnings. Also we
5502 -- are all done if we now have a raise SE node.
5508 -- If call is to immediately containing subprogram, then check for
5509 -- the case of a possible run-time detectable infinite recursion.
5511 else
5515 -- Although in general case, recursion is not statically
5516 -- checkable, the case of calling an immediately containing
5517 -- subprogram is easy to catch.
5521 -- If the recursive call is to a parameterless subprogram,
5522 -- then even if we can't statically detect infinite
5523 -- recursion, this is pretty suspicious, and we output a
5524 -- warning. Furthermore, we will try later to detect some
5525 -- cases here at run time by expanding checking code (see
5526 -- Detect_Infinite_Recursion in package Exp_Ch6).
5528 -- If the recursive call is within a handler, do not emit a
5529 -- warning, because this is a common idiom: loop until input
5530 -- is correct, catch illegal input in handler and restart.
5536 then
5537 -- For the case of a procedure call. We give the message
5538 -- only if the call is the first statement in a sequence
5539 -- of statements, or if all previous statements are
5540 -- simple assignments. This is simply a heuristic to
5541 -- decrease false positives, without losing too many good
5542 -- warnings. The idea is that these previous statements
5543 -- may affect global variables the procedure depends on.
5544 -- We also exclude raise statements, that may arise from
5545 -- constraint checks and are probably unrelated to the
5546 -- intended control flow.
5550 then
5551 declare
5553 begin
5557 N_Assignment_Statement,
5558 N_Raise_Constraint_Error)
5559 then
5568 -- Do not give warning if we are in a conditional context
5570 declare
5572 begin
5578 then
5583 -- Here warning is to be issued
5586 Error_Msg_N
5588 Error_Msg_N
5600 -- Check obsolescent reference to Ada.Characters.Handling subprogram
5604 -- If subprogram name is a predefined operator, it was given in
5605 -- functional notation. Replace call node with operator node, so
5606 -- that actuals can be resolved appropriately.
5614 then
5620 -- Create a transient scope if the resulting type requires it
5622 -- There are several notable exceptions:
5624 -- a) In init procs, the transient scope overhead is not needed, and is
5625 -- even incorrect when the call is a nested initialization call for a
5626 -- component whose expansion may generate adjust calls. However, if the
5627 -- call is some other procedure call within an initialization procedure
5628 -- (for example a call to Create_Task in the init_proc of the task
5629 -- run-time record) a transient scope must be created around this call.
5631 -- b) Enumeration literal pseudo-calls need no transient scope
5633 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
5634 -- functions) do not use the secondary stack even though the return
5635 -- type may be unconstrained.
5637 -- d) Calls to a build-in-place function, since such functions may
5638 -- allocate their result directly in a target object, and cases where
5639 -- the result does get allocated in the secondary stack are checked for
5640 -- within the specialized Exp_Ch6 procedures for expanding those
5641 -- build-in-place calls.
5643 -- e) If the subprogram is marked Inline_Always, then even if it returns
5644 -- an unconstrained type the call does not require use of the secondary
5645 -- stack. However, inlining will only take place if the body to inline
5646 -- is already present. It may not be available if e.g. the subprogram is
5647 -- declared in a child instance.
5649 -- If this is an initialization call for a type whose construction
5650 -- uses the secondary stack, and it is not a nested call to initialize
5651 -- a component, we do need to create a transient scope for it. We
5652 -- check for this by traversing the type in Check_Initialization_Call.
5658 and then not Debug_Flag_Dot_K
5659 then
5666 and then Debug_Flag_Dot_K
5667 then
5673 then
5676 elsif Full_Expander_Active
5679 and then
5681 or else
5683 then
5686 -- If the call appears within the bounds of a loop, it will
5687 -- be rewritten and reanalyzed, nothing left to do here.
5694 and then not Within_Init_Proc
5695 then
5699 -- A protected function cannot be called within the definition of the
5700 -- enclosing protected type.
5705 then
5706 Error_Msg_NE
5710 -- Propagate interpretation to actuals, and add default expressions
5711 -- where needed.
5716 -- Overloaded literals are rewritten as function calls, for purpose of
5717 -- resolution. After resolution, we can replace the call with the
5718 -- literal itself.
5724 -- Avoid validation, since it is a static function call
5730 -- If the subprogram is not global, then kill all saved values and
5731 -- checks. This is a bit conservative, since in many cases we could do
5732 -- better, but it is not worth the effort. Similarly, we kill constant
5733 -- values. However we do not need to do this for internal entities
5734 -- (unless they are inherited user-defined subprograms), since they
5735 -- are not in the business of molesting local values.
5737 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5738 -- kill all checks and values for calls to global subprograms. This
5739 -- takes care of the case where an access to a local subprogram is
5740 -- taken, and could be passed directly or indirectly and then called
5741 -- from almost any context.
5743 -- Note: we do not do this step till after resolving the actuals. That
5744 -- way we still take advantage of the current value information while
5745 -- scanning the actuals.
5747 -- We suppress killing values if we are processing the nodes associated
5748 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5749 -- type kills all the values as part of analyzing the code that
5750 -- initializes the dispatch tables.
5754 or else Suppress_Value_Tracking_On_Call
5759 then
5760 Kill_Current_Values;
5763 -- If we are warning about unread OUT parameters, this is the place to
5764 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5765 -- after the above call to Kill_Current_Values (since that call clears
5766 -- the Last_Assignment field of all local variables).
5771 then
5772 declare
5776 begin
5786 then
5796 -- If the subprogram is a primitive operation, check whether or not
5797 -- it is a correct dispatching call.
5801 then
5806 and then not In_Instance
5807 then
5811 -- If this is a dispatching call, generate the appropriate reference,
5812 -- for better source navigation in GPS.
5816 then
5819 -- Normal case, not a dispatching call: generate a call reference
5821 else
5829 -- Check for violation of restriction No_Specific_Termination_Handlers
5830 -- and warn on a potentially blocking call to Abort_Task.
5834 or else
5836 then
5843 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
5844 -- timing event violates restriction No_Relative_Delay (AI-0211). We
5845 -- need to check the second argument to determine whether it is an
5846 -- absolute or relative timing event.
5851 then
5855 -- Issue an error for a call to an eliminated subprogram. This routine
5856 -- will not perform the check if the call appears within a default
5857 -- expression.
5861 -- In formal mode, the primitive operations of a tagged type or type
5862 -- extension do not include functions that return the tagged type.
5864 -- Commented out as the call to Is_Inherited_Operation_For_Type may
5865 -- cause an error because the type entity of the parent node of
5866 -- Entity (Name (N) may not be set. ???
5867 -- So why not just add a guard ???
5869 -- if Nkind (N) = N_Function_Call
5870 -- and then Is_Tagged_Type (Etype (N))
5871 -- and then Is_Entity_Name (Name (N))
5872 -- and then Is_Inherited_Operation_For_Type
5873 -- (Entity (Name (N)), Etype (N))
5874 -- then
5875 -- Check_SPARK_Restriction ("function not inherited", N);
5876 -- end if;
5878 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
5879 -- class-wide and the call dispatches on result in a context that does
5880 -- not provide a tag, the call raises Program_Error.
5883 and then In_Instance
5888 then
5889 -- Verify that none of the formals are controlling
5891 declare
5895 begin
5916 -- Check the dimensions of the actuals in the call. For function calls,
5917 -- propagate the dimensions from the returned type to N.
5921 -- All done, evaluate call and deal with elaboration issues
5928 -----------------------------
5929 -- Resolve_Case_Expression --
5930 -----------------------------
5935 begin
5945 -- If we still have a case expression, and overflow checks are enabled
5946 -- in MINIMIZED or ELIMINATED modes, then set Do_Overflow_Check to
5947 -- ensure that we handle overflow for dependent expressions.
5951 then
5956 -------------------------------
5957 -- Resolve_Character_Literal --
5958 -------------------------------
5964 begin
5965 -- Verify that the character does belong to the type of the context
5970 -- Wide_Wide_Character literals must always be defined, since the set
5971 -- of wide wide character literals is complete, i.e. if a character
5972 -- literal is accepted by the parser, then it is OK for wide wide
5973 -- character (out of range character literals are rejected).
5978 -- Always accept character literal for type Any_Character, which
5979 -- occurs in error situations and in comparisons of literals, both
5980 -- of which should accept all literals.
5985 -- For Standard.Character or a type derived from it, check that the
5986 -- literal is in range.
5993 -- For Standard.Wide_Character or a type derived from it, check that the
5994 -- literal is in range.
6001 -- For Standard.Wide_Wide_Character or a type derived from it, we
6002 -- know the literal is in range, since the parser checked!
6007 -- If the entity is already set, this has already been resolved in a
6008 -- generic context, or comes from expansion. Nothing else to do.
6013 -- Otherwise we have a user defined character type, and we can use the
6014 -- standard visibility mechanisms to locate the referenced entity.
6016 else
6029 -- If we fall through, then the literal does not match any of the
6030 -- entries of the enumeration type. This isn't just a constraint error
6031 -- situation, it is an illegality (see RM 4.2).
6033 Error_Msg_NE
6037 ---------------------------
6038 -- Resolve_Comparison_Op --
6039 ---------------------------
6041 -- Context requires a boolean type, and plays no role in resolution.
6042 -- Processing identical to that for equality operators. The result type is
6043 -- the base type, which matters when pathological subtypes of booleans with
6044 -- limited ranges are used.
6051 begin
6052 -- If this is an intrinsic operation which is not predefined, use the
6053 -- types of its declared arguments to resolve the possibly overloaded
6054 -- operands. Otherwise the operands are unambiguous and specify the
6055 -- expected type.
6060 else
6071 -- Skip remaining processing if already set to Any_Type
6077 -- Deal with other error cases
6081 T = Any_Character
6082 then
6085 else
6093 -- Resolve the operands if types OK
6102 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6103 -- types or array types except String.
6106 Check_SPARK_Restriction
6111 then
6112 Check_SPARK_Restriction
6116 -- Check comparison on unordered enumeration
6120 then
6124 -- Evaluate the relation (note we do this after the above check since
6125 -- this Eval call may change N to True/False.
6131 -----------------------------------------
6132 -- Resolve_Discrete_Subtype_Indication --
6133 -----------------------------------------
6135 procedure Resolve_Discrete_Subtype_Indication
6138 is
6142 begin
6150 else
6160 Error_Msg_NE
6163 -- Rewrite the constraint as a range of Typ
6164 -- to allow compilation to proceed further.
6176 else
6180 -- Additionally, we must check that the bounds are compatible
6181 -- with the given subtype, which might be different from the
6182 -- type of the context.
6186 -- ??? If the above check statically detects a Constraint_Error
6187 -- it replaces the offending bound(s) of the range R with a
6188 -- Constraint_Error node. When the itype which uses these bounds
6189 -- is frozen the resulting call to Duplicate_Subexpr generates
6190 -- a new temporary for the bounds.
6192 -- Unfortunately there are other itypes that are also made depend
6193 -- on these bounds, so when Duplicate_Subexpr is called they get
6194 -- a forward reference to the newly created temporaries and Gigi
6195 -- aborts on such forward references. This is probably sign of a
6196 -- more fundamental problem somewhere else in either the order of
6197 -- itype freezing or the way certain itypes are constructed.
6199 -- To get around this problem we call Remove_Side_Effects right
6200 -- away if either bounds of R are a Constraint_Error.
6202 declare
6206 begin
6222 -------------------------
6223 -- Resolve_Entity_Name --
6224 -------------------------
6226 -- Used to resolve identifiers and expanded names
6231 begin
6232 -- If garbage from errors, set to Any_Type and return
6239 -- Replace named numbers by corresponding literals. Note that this is
6240 -- the one case where Resolve_Entity_Name must reset the Etype, since
6241 -- it is currently marked as universal.
6251 -- For enumeration literals, we need to make sure that a proper style
6252 -- check is done, since such literals are overloaded, and thus we did
6253 -- not do a style check during the first phase of analysis.
6259 -- Case of subtype name appearing as an operand in expression
6263 -- Allow use of subtype if it is a concurrent type where we are
6264 -- currently inside the body. This will eventually be expanded into a
6265 -- call to Self (for tasks) or _object (for protected objects). Any
6266 -- other use of a subtype is invalid.
6270 then
6273 -- Any other use is an error
6275 else
6276 Error_Msg_N
6280 -- Check discriminant use if entity is discriminant in current scope,
6281 -- i.e. discriminant of record or concurrent type currently being
6282 -- analyzed. Uses in corresponding body are unrestricted.
6287 then
6290 -- A parameterless generic function cannot appear in a context that
6291 -- requires resolution.
6302 then
6305 -- In all other cases, just do the possible static evaluation
6307 else
6308 -- A deferred constant that appears in an expression must have a
6309 -- completion, unless it has been removed by in-place expansion of
6310 -- an aggregate.
6316 and then not In_Spec_Expression
6318 then
6322 then
6324 else
6325 Error_Msg_N (
6334 -------------------
6335 -- Resolve_Entry --
6336 -------------------
6348 -- If the bounds of the entry family being called depend on task
6349 -- discriminants, build a new index subtype where a discriminant is
6350 -- replaced with the value of the discriminant of the target task.
6351 -- The target task is the prefix of the entry name in the call.
6353 -----------------------
6354 -- Actual_Index_Type --
6355 -----------------------
6365 -- If the bound is given by a discriminant, replace with a reference
6366 -- to the discriminant of the same name in the target task. If the
6367 -- entry name is the target of a requeue statement and the entry is
6368 -- in the current protected object, the bound to be used is the
6369 -- discriminal of the object (see Apply_Range_Checks for details of
6370 -- the transformation).
6372 -----------------------------
6373 -- Actual_Discriminant_Ref --
6374 -----------------------------
6380 begin
6385 then
6391 then
6392 -- Note: here Bound denotes a discriminant of the corresponding
6393 -- record type tskV, whose discriminal is a formal of the
6394 -- init-proc tskVIP. What we want is the body discriminal,
6395 -- which is associated to the discriminant of the original
6396 -- concurrent type tsk.
6398 return New_Occurrence_Of
6401 else
6402 Ref :=
6412 -- Start of processing for Actual_Index_Type
6414 begin
6417 then
6420 else
6434 -- Start of processing of Resolve_Entry
6436 begin
6437 -- Find name of entry being called, and resolve prefix of name with its
6438 -- own type. The prefix can be overloaded, and the name and signature of
6439 -- the entry must be taken into account.
6443 -- Case of dealing with entry family within the current tasks
6447 else
6453 -- Entry call to an entry (or entry family) in the current task. This
6454 -- is legal even though the task will deadlock. Rewrite as call to
6455 -- current task.
6457 -- This can also be a call to an entry in an enclosing task. If this
6458 -- is a single task, we have to retrieve its name, because the scope
6459 -- of the entry is the task type, not the object. If the enclosing
6460 -- task is a task type, the identity of the task is given by its own
6461 -- self variable.
6463 -- Finally this can be a requeue on an entry of the same task or
6464 -- protected object.
6471 then
6472 -- S is an enclosing task or protected object. The concurrent
6473 -- declaration has been converted into a type declaration, and
6474 -- the object itself has an object declaration that follows
6475 -- the type in the same declarative part.
6487 -- Call to current task. Will be transformed into call to Self
6494 New_N :=
6497 Selector_Name =>
6504 then
6505 -- Use the entry name (which must be unique at this point) to find
6506 -- the prefix that returns the corresponding task/protected type.
6508 declare
6514 begin
6536 -- Up to this point the expression could have been the actual in a
6537 -- simple entry call, and be given by a named association.
6541 else
6547 ------------------------
6548 -- Resolve_Entry_Call --
6549 ------------------------
6561 begin
6562 -- We kill all checks here, because it does not seem worth the effort to
6563 -- do anything better, an entry call is a big operation.
6565 Kill_All_Checks;
6567 -- Processing of the name is similar for entry calls and protected
6568 -- operation calls. Once the entity is determined, we can complete
6569 -- the resolution of the actuals.
6571 -- The selector may be overloaded, in the case of a protected object
6572 -- with overloaded functions. The type of the context is used for
6573 -- resolution.
6578 then
6579 declare
6583 begin
6602 -- Simple entry call
6610 -- Call to member of entry family
6617 -- We cannot in general check the maximum depth of protected entry calls
6618 -- at compile time. But we can tell that any protected entry call at all
6619 -- violates a specified nesting depth of zero.
6625 -- Use context type to disambiguate a protected function that can be
6626 -- called without actuals and that returns an array type, and where the
6627 -- argument list may be an indexing of the returned value.
6632 and then
6638 and then
6639 Covers
6642 then
6643 declare
6646 begin
6647 Index_Node :=
6649 Prefix =>
6653 -- Since we are correcting a node classification error made by the
6654 -- parser, we call Replace rather than Rewrite.
6667 then
6668 -- Rewrite as call to the precondition wrapper, adding the task
6669 -- object to the list of actuals. If the call is to a member of an
6670 -- entry family, include the index as well.
6672 declare
6676 begin
6685 New_Call :=
6687 Name =>
6696 -- The operation name may have been overloaded. Order the actuals
6697 -- according to the formals of the resolved entity, and set the return
6698 -- type to that of the operation.
6709 -- Create a call reference to the entry
6717 -- Verify that a procedure call cannot masquerade as an entry
6718 -- call where an entry call is expected.
6723 then
6728 then
6733 then
6738 -- After resolution, entry calls and protected procedure calls are
6739 -- changed into entry calls, for expansion. The structure of the node
6740 -- does not change, so it can safely be done in place. Protected
6741 -- function calls must keep their structure because they are
6742 -- subexpressions.
6746 -- A protected operation that is not a function may modify the
6747 -- corresponding object, and cannot apply to a constant. If this
6748 -- is an internal call, the prefix is the type itself.
6754 then
6755 Error_Msg_N
6757 Entry_Name);
6771 -- Protected functions can return on the secondary stack, in which
6772 -- case we must trigger the transient scope mechanism.
6774 elsif Full_Expander_Active
6776 then
6781 -------------------------
6782 -- Resolve_Equality_Op --
6783 -------------------------
6785 -- Both arguments must have the same type, and the boolean context does
6786 -- not participate in the resolution. The first pass verifies that the
6787 -- interpretation is not ambiguous, and the type of the left argument is
6788 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
6789 -- are strings or aggregates, allocators, or Null, they are ambiguous even
6790 -- though they carry a single (universal) type. Diagnose this case here.
6798 -- The resolution rule for if expressions requires that each such must
6799 -- have a unique type. This means that if several dependent expressions
6800 -- are of a non-null anonymous access type, and the context does not
6801 -- impose an expected type (as can be the case in an equality operation)
6802 -- the expression must be rejected.
6805 -- In the case of allocators, make a last-ditch attempt to find a single
6806 -- access type with the right designated type. This is semantically
6807 -- dubious, and of no interest to any real code, but c48008a makes it
6808 -- all worthwhile.
6810 -------------------------
6811 -- Check_If_Expression --
6812 -------------------------
6818 begin
6825 then
6831 -----------------------------
6832 -- Find_Unique_Access_Type --
6833 -----------------------------
6840 begin
6845 else
6857 then
6870 -- Start of processing for Resolve_Equality_Op
6872 begin
6883 T = Any_Character
6884 then
6887 else
6896 then
6905 -- If expressions must have a single type, and if the context does
6906 -- not impose one the dependent expressions cannot be anonymous
6907 -- access types.
6909 -- Why no similar processing for case expressions???
6913 E_Anonymous_Access_Subprogram_Type)
6915 E_Anonymous_Access_Subprogram_Type)
6916 then
6924 -- In SPARK, equality operators = and /= for array types other than
6925 -- String are only defined when, for each index position, the
6926 -- operands have equal static bounds.
6930 -- Protect call to Matching_Static_Array_Bounds to avoid costly
6931 -- operation if not needed.
6939 then
6940 Check_SPARK_Restriction
6945 -- If the unique type is a class-wide type then it will be expanded
6946 -- into a dispatching call to the predefined primitive. Therefore we
6947 -- check here for potential violation of such restriction.
6953 if Warn_On_Redundant_Constructs
6958 then
6959 Error_Msg_N -- CODEFIX
6968 -- If this is an inequality, it may be the implicit inequality
6969 -- created for a user-defined operation, in which case the corres-
6970 -- ponding equality operation is not intrinsic, and the operation
6971 -- cannot be constant-folded. Else fold.
6976 or else Is_Intrinsic_Subprogram
6978 then
6984 then
6988 -- Ada 2005: If one operand is an anonymous access type, convert the
6989 -- other operand to it, to ensure that the underlying types match in
6990 -- the back-end. Same for access_to_subprogram, and the conversion
6991 -- verifies that the types are subtype conformant.
6993 -- We apply the same conversion in the case one of the operands is a
6994 -- private subtype of the type of the other.
6996 -- Why the Expander_Active test here ???
6998 if Full_Expander_Active
6999 and then
7001 E_Anonymous_Access_Subprogram_Type)
7003 then
7023 ----------------------------------
7024 -- Resolve_Explicit_Dereference --
7025 ----------------------------------
7033 -- The candidate prefix type, if overloaded
7038 begin
7044 -- Use the context type to select the prefix that has the correct
7045 -- designated type. Keep the first match, which will be the inner-
7046 -- most.
7053 then
7058 -- Remove access types that do not match, but preserve access
7059 -- to subprogram interpretations, in case a further dereference
7060 -- is needed (see below).
7073 else
7074 -- If no interpretation covers the designated type of the prefix,
7075 -- this is the pathological case where not all implementations of
7076 -- the prefix allow the interpretation of the node as a call. Now
7077 -- that the expected type is known, Remove other interpretations
7078 -- from prefix, rewrite it as a call, and resolve again, so that
7079 -- the proper call node is generated.
7090 New_N :=
7092 Name =>
7103 -- If not overloaded, resolve P with its own type
7105 else
7113 -- If the designated type is a packed unconstrained array type, and the
7114 -- explicit dereference is not in the context of an attribute reference,
7115 -- then we must compute and set the actual subtype, since it is needed
7116 -- by Gigi. The reason we exclude the attribute case is that this is
7117 -- handled fine by Gigi, and in fact we use such attributes to build the
7118 -- actual subtype. We also exclude generated code (which builds actual
7119 -- subtypes directly if they are needed).
7126 then
7130 -- Note: No Eval processing is required for an explicit dereference,
7131 -- because such a name can never be static.
7135 -------------------------------------
7136 -- Resolve_Expression_With_Actions --
7137 -------------------------------------
7140 begin
7144 ---------------------------
7145 -- Resolve_If_Expression --
7146 ---------------------------
7155 begin
7160 -- When the "then" expression is of a scalar type different from the
7161 -- result type, then insert a conversion to ensure the generation of
7162 -- a constraint check.
7166 then
7171 -- If ELSE expression present, just resolve using the determined type
7179 then
7184 -- If no ELSE expression is present, root type must be Standard.Boolean
7185 -- and we provide a Standard.True result converted to the appropriate
7186 -- Boolean type (in case it is a derived boolean type).
7189 Else_Expr :=
7194 else
7202 -- If we still have a if expression, and overflow checks are enabled in
7203 -- MINIMIZED or ELIMINATED modes, then set Do_Overflow_Check to ensure
7204 -- that we handle overflow for dependent expressions.
7208 then
7213 -------------------------------
7214 -- Resolve_Indexed_Component --
7215 -------------------------------
7223 begin
7226 -- Use the context type to select the prefix that yields the correct
7227 -- component type.
7229 declare
7236 begin
7243 and then
7244 Covers
7247 then
7256 else
7262 else
7273 else
7280 -- If prefix is access type, dereference to get real array type.
7281 -- Note: we do not apply an access check because the expander always
7282 -- introduces an explicit dereference, and the check will happen there.
7288 -- If name was overloaded, set component type correctly now
7289 -- If a misplaced call to an entry family (which has no index types)
7290 -- return. Error will be diagnosed from calling context.
7294 else
7301 -- The prefix may have resolved to a string literal, in which case its
7302 -- etype has a special representation. This is only possible currently
7303 -- if the prefix is a static concatenation, written in functional
7304 -- notation.
7309 else
7316 else
7327 -- Do not generate the warning on suspicious index if we are analyzing
7328 -- package Ada.Tags; otherwise we will report the warning with the
7329 -- Prims_Ptr field of the dispatch table.
7332 or else not
7334 Ada_Tags)
7335 then
7340 -- If the array type is atomic, and is packed, and we are in a left side
7341 -- context, then this is worth a warning, since we have a situation
7342 -- where the access to the component may cause extra read/writes of
7343 -- the atomic array object, which could be considered unexpected.
7351 then
7359 -----------------------------
7360 -- Resolve_Integer_Literal --
7361 -----------------------------
7364 begin
7369 --------------------------------
7370 -- Resolve_Intrinsic_Operator --
7371 --------------------------------
7381 -- If the operand is a literal, it cannot be the expression in a
7382 -- conversion. Use a qualified expression instead.
7387 begin
7389 Res :=
7395 else
7402 -- Start of processing for Resolve_Intrinsic_Operator
7404 begin
7405 -- We must preserve the original entity in a generic setting, so that
7406 -- the legality of the operation can be verified in an instance.
7421 -- If the result or operand types are private, rewrite with unchecked
7422 -- conversions on the operands and the result, to expose the proper
7423 -- underlying numeric type.
7428 then
7430 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
7431 -- What on earth is this commented out fragment of code???
7435 else
7456 then
7457 -- Add explicit conversion where needed, and save interpretations in
7458 -- case operands are overloaded. If the context is a VMS operation,
7459 -- assert that the conversion is legal (the operands have the proper
7460 -- types to select the VMS intrinsic). Note that in rare cases the
7461 -- VMS operators may be visible, but the default System is being used
7462 -- and Address is a private type.
7473 else
7483 else
7493 else
7498 --------------------------------------
7499 -- Resolve_Intrinsic_Unary_Operator --
7500 --------------------------------------
7502 procedure Resolve_Intrinsic_Unary_Operator
7505 is
7510 begin
7529 else
7534 ------------------------
7535 -- Resolve_Logical_Op --
7536 ------------------------
7541 begin
7544 -- Predefined operations on scalar types yield the base type. On the
7545 -- other hand, logical operations on arrays yield the type of the
7546 -- arguments (and the context).
7550 else
7554 -- OK if this is a VMS-specific intrinsic operation
7559 -- The following test is required because the operands of the operation
7560 -- may be literals, in which case the resulting type appears to be
7561 -- compatible with a signed integer type, when in fact it is compatible
7562 -- only with modular types. If the context itself is universal, the
7563 -- operation is illegal.
7571 Error_Msg_N
7579 then
7583 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
7584 -- is active and the result type is standard Boolean (do not mess with
7585 -- ops that return a nonstandard Boolean type, because something strange
7586 -- is going on).
7588 -- Note: you might expect this replacement to be done during expansion,
7589 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
7590 -- is used, no part of the right operand of an "and" or "or" operator
7591 -- should be executed if the left operand would short-circuit the
7592 -- evaluation of the corresponding "and then" or "or else". If we left
7593 -- the replacement to expansion time, then run-time checks associated
7594 -- with such operands would be evaluated unconditionally, due to being
7595 -- before the condition prior to the rewriting as short-circuit forms
7596 -- during expansion.
7598 if Short_Circuit_And_Or
7601 then
7609 -- Case of OR changed to OR ELSE
7611 else
7619 -- Return now, since analysis of the rewritten ops will take care of
7620 -- other reference bookkeeping and expression folding.
7635 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
7636 -- only when both operands have same static lower and higher bounds. Of
7637 -- course the types have to match, so only check if operands are
7638 -- compatible and the node itself has no errors.
7642 then
7643 declare
7647 begin
7648 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7649 -- operation if not needed.
7656 then
7657 Check_SPARK_Restriction
7664 ---------------------------
7665 -- Resolve_Membership_Op --
7666 ---------------------------
7668 -- The context can only be a boolean type, and does not determine the
7669 -- arguments. Arguments should be unambiguous, but the preference rule for
7670 -- universal types applies.
7680 -- Analysis has determined a unique type for the left operand. Use it to
7681 -- resolve the disjuncts.
7683 ----------------------------
7684 -- Resolve_Set_Membership --
7685 ----------------------------
7691 begin
7697 -- Alternative is an expression, a range
7698 -- or a subtype mark.
7702 then
7709 -- Check for duplicates for discrete case
7712 declare
7721 begin
7722 -- Loop checking duplicates. This is quadratic, but giant sets
7723 -- are unlikely in this context so it's a reasonable choice.
7730 N_Character_Literal)
7732 then
7750 -- Start of processing for Resolve_Membership_Op
7752 begin
7758 Resolve_Set_Membership;
7762 and then
7764 or else
7767 then
7770 -- Ada 2005 (AI-251): Support the following case:
7772 -- type I is interface;
7773 -- type T is tagged ...
7775 -- function Test (O : I'Class) is
7776 -- begin
7777 -- return O in T'Class.
7778 -- end Test;
7780 -- In this case we have nothing else to do. The membership test will be
7781 -- done at run time.
7788 then
7790 else
7794 -- If mixed-mode operations are present and operands are all literal,
7795 -- the only interpretation involves Duration, which is probably not
7796 -- the intention of the programmer.
7811 then
7817 else
7825 ------------------
7826 -- Resolve_Null --
7827 ------------------
7832 begin
7833 -- Handle restriction against anonymous null access values This
7834 -- restriction can be turned off using -gnatdj.
7836 -- Ada 2005 (AI-231): Remove restriction
7839 and then not Debug_Flag_J
7842 then
7843 -- In the common case of a call which uses an explicitly null value
7844 -- for an access parameter, give specialized error message.
7847 Error_Msg_N
7850 -- Standard message for all other cases (are there any?)
7852 else
7853 Error_Msg_N
7858 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
7859 -- assignment to a null-excluding object
7864 then
7866 Insert_Action
7871 else
7878 -- In a distributed context, null for a remote access to subprogram may
7879 -- need to be replaced with a special record aggregate. In this case,
7880 -- return after having done the transformation.
7885 then
7889 -- The null literal takes its type from the context
7894 -----------------------
7895 -- Resolve_Op_Concat --
7896 -----------------------
7900 -- We wish to avoid deep recursion, because concatenations are often
7901 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
7902 -- operands nonrecursively until we find something that is not a simple
7903 -- concatenation (A in this case). We resolve that, and then walk back
7904 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
7905 -- to do the rest of the work at each level. The Parent pointers allow
7906 -- us to avoid recursion, and thus avoid running out of memory. See also
7907 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
7912 begin
7913 -- The following code is equivalent to:
7915 -- Resolve_Op_Concat_First (NN, Typ);
7916 -- Resolve_Op_Concat_Arg (N, ...);
7917 -- Resolve_Op_Concat_Rest (N, Typ);
7919 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
7920 -- operand is a concatenation.
7922 -- Walk down left operands
7924 loop
7933 -- Now (given the above example) NN is A&B and Op1 is A
7935 -- First resolve Op1 ...
7939 -- ... then walk NN back up until we reach N (where we started), calling
7940 -- Resolve_Op_Concat_Rest along the way.
7942 loop
7949 Check_SPARK_Restriction
7954 ---------------------------
7955 -- Resolve_Op_Concat_Arg --
7956 ---------------------------
7958 procedure Resolve_Op_Concat_Arg
7963 is
7967 begin
7969 if Is_Comp
7973 then
7975 else
7979 -- If both Array & Array and Array & Component are visible, there is a
7980 -- potential ambiguity that must be reported.
7985 then
7989 -- If the operation is user-defined and not overloaded use its
7990 -- profile. The operation may be a renaming, in which case it has
7991 -- been rewritten, and we want the original profile.
7996 then
7998 Etype
8002 -- Otherwise an aggregate may match both the array type and the
8003 -- component type.
8005 else
8010 else
8014 then
8015 declare
8020 begin
8025 -- Special-case the error message when the overloading is
8026 -- caused by a function that yields an array and can be
8027 -- called without parameters.
8032 Error_Msg_NE
8034 Error_Msg_NE
8038 else
8046 or else
8048 then
8049 Error_Msg_N -- CODEFIX
8067 else
8072 else
8076 -- Concatenation is restricted in SPARK: each operand must be either a
8077 -- string literal, the name of a string constant, a static character or
8078 -- string expression, or another concatenation. Arg cannot be a
8079 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
8080 -- separately on each final operand, past concatenation operations.
8084 Check_SPARK_Restriction
8092 then
8093 Check_SPARK_Restriction
8097 -- Do not issue error on an operand that is neither a character nor a
8098 -- string, as the error is issued in Resolve_Op_Concat.
8100 else
8107 -----------------------------
8108 -- Resolve_Op_Concat_First --
8109 -----------------------------
8116 begin
8117 -- The parser folds an enormous sequence of concatenations of string
8118 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
8119 -- in the right operand. If the expression resolves to a predefined "&"
8120 -- operator, all is well. Otherwise, the parser's folding is wrong, so
8121 -- we give an error. See P_Simple_Expression in Par.Ch4.
8126 then
8141 ----------------------------
8142 -- Resolve_Op_Concat_Rest --
8143 ----------------------------
8149 begin
8158 -- If this is not a static concatenation, but the result is a string
8159 -- type (and not an array of strings) ensure that static string operands
8160 -- have their subtypes properly constructed.
8164 then
8170 ----------------------
8171 -- Resolve_Op_Expon --
8172 ----------------------
8177 begin
8178 -- Catch attempts to do fixed-point exponentiation with universal
8179 -- operands, which is a case where the illegality is not caught during
8180 -- normal operator analysis.
8190 then
8199 then
8206 then
8210 -- We do the resolution using the base type, because intermediate values
8211 -- in expressions always are of the base type, not a subtype of it.
8225 -- Evaluate the exponentiation operator for dimensioned type
8228 else
8232 -- Set overflow checking bit. Much cleverer code needed here eventually
8233 -- and perhaps the Resolve routines should be separated for the various
8234 -- arithmetic operations, since they will need different processing. ???
8243 --------------------
8244 -- Resolve_Op_Not --
8245 --------------------
8251 -- This function determines if the parent node is a boolean operator or
8252 -- operation (comparison op, membership test, or short circuit form) and
8253 -- the not in question is the left operand of this operation. Note that
8254 -- if the not is in parens, then false is returned.
8256 -----------------------
8257 -- Parent_Is_Boolean --
8258 -----------------------
8261 begin
8265 else
8267 when N_Op_And |
8268 N_Op_Eq |
8269 N_Op_Ge |
8270 N_Op_Gt |
8271 N_Op_Le |
8272 N_Op_Lt |
8273 N_Op_Ne |
8274 N_Op_Or |
8275 N_Op_Xor |
8276 N_In |
8277 N_Not_In |
8278 N_And_Then |
8279 N_Or_Else =>
8289 -- Start of processing for Resolve_Op_Not
8291 begin
8292 -- Predefined operations on scalar types yield the base type. On the
8293 -- other hand, logical operations on arrays yield the type of the
8294 -- arguments (and the context).
8298 else
8305 -- Straightforward case of incorrect arguments
8312 -- Special case of probable missing parens
8316 Error_Msg_N
8319 else
8320 Error_Msg_N
8327 -- OK resolution of NOT
8329 else
8330 -- Warn if non-boolean types involved. This is a case like not a < b
8331 -- where a and b are modular, where we will get (not a) < b and most
8332 -- likely not (a < b) was intended.
8334 if Warn_On_Questionable_Missing_Parens
8336 and then Parent_Is_Boolean
8337 then
8341 -- Warn on double negation if checking redundant constructs
8343 if Warn_On_Redundant_Constructs
8348 then
8352 -- Complete resolution and evaluation of NOT
8362 -----------------------------
8363 -- Resolve_Operator_Symbol --
8364 -----------------------------
8366 -- Nothing to be done, all resolved already
8372 begin
8376 ----------------------------------
8377 -- Resolve_Qualified_Expression --
8378 ----------------------------------
8386 begin
8389 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8390 -- operation if not needed.
8397 then
8398 Check_SPARK_Restriction
8402 -- A qualified expression requires an exact match of the type, class-
8403 -- wide matching is not allowed. However, if the qualifying type is
8404 -- specific and the expression has a class-wide type, it may still be
8405 -- okay, since it can be the result of the expansion of a call to a
8406 -- dispatching function, so we also have to check class-wideness of the
8407 -- type of the expression's original node.
8410 or else
8414 then
8418 -- If the target type is unconstrained, then we reset the type of the
8419 -- result from the type of the expression. For other cases, the actual
8420 -- subtype of the expression is the target type.
8424 then
8432 -------------------
8433 -- Resolve_Range --
8434 -------------------
8441 -- Returns True if N is of the form X'First .. X'Last where X is the
8442 -- same entity for both attributes.
8444 --------------------
8445 -- First_Last_Ref --
8446 --------------------
8452 begin
8457 then
8458 declare
8461 begin
8465 then
8474 -- Start of processing for Resolve_Range
8476 begin
8481 -- Check for inappropriate range on unordered enumeration type
8485 -- Exclude X'First .. X'Last if X is the same entity for both
8487 and then not First_Last_Ref
8488 then
8495 -- We have to check the bounds for being within the base range as
8496 -- required for a non-static context. Normally this is automatic and
8497 -- done as part of evaluating expressions, but the N_Range node is an
8498 -- exception, since in GNAT we consider this node to be a subexpression,
8499 -- even though in Ada it is not. The circuit in Sem_Eval could check for
8500 -- this, but that would put the test on the main evaluation path for
8501 -- expressions.
8506 -- Check for an ambiguous range over character literals. This will
8507 -- happen with a membership test involving only literals.
8515 -- If bounds are static, constant-fold them, so size computations are
8516 -- identical between front-end and back-end. Do not perform this
8517 -- transformation while analyzing generic units, as type information
8518 -- would be lost when reanalyzing the constant node in the instance.
8531 --------------------------
8532 -- Resolve_Real_Literal --
8533 --------------------------
8538 begin
8539 -- Special processing for fixed-point literals to make sure that the
8540 -- value is an exact multiple of small where this is required. We skip
8541 -- this for the universal real case, and also for generic types.
8547 then
8548 declare
8555 begin
8556 -- Case of literal is not an exact multiple of the Small
8560 -- For a source program literal for a decimal fixed-point type,
8561 -- this is statically illegal (RM 4.9(36)).
8566 then
8570 -- Generate a warning if literal from source
8573 and then Warn_On_Bad_Fixed_Value
8574 then
8575 Error_Msg_N
8577 N);
8580 -- Replace literal by a value that is the exact representation
8581 -- of a value of the type, i.e. a multiple of the small value,
8582 -- by truncation, since Machine_Rounds is false for all GNAT
8583 -- fixed-point types (RM 4.9(38)).
8593 -- In all cases, set the corresponding integer field
8599 -- Now replace the actual type by the expected type as usual
8605 -----------------------
8606 -- Resolve_Reference --
8607 -----------------------
8612 begin
8613 -- Replace general access with specific type
8621 -- If we are taking the reference of a volatile entity, then treat it as
8622 -- a potential modification of this entity. This is too conservative,
8623 -- but necessary because remove side effects can cause transformations
8624 -- of normal assignments into reference sequences that otherwise fail to
8625 -- notice the modification.
8632 --------------------------------
8633 -- Resolve_Selected_Component --
8634 --------------------------------
8649 -- Check whether this is the initialization of a component within an
8650 -- init proc (by assignment or call to another init proc). If true,
8651 -- there is no need for a discriminant check.
8653 --------------------
8654 -- Init_Component --
8655 --------------------
8658 begin
8659 return Inside_Init_Proc
8665 -- Start of processing for Resolve_Selected_Component
8667 begin
8670 -- Use the context type to select the prefix that has a selector
8671 -- of the correct name and type.
8679 else
8683 -- Locate selected component. For a private prefix the selector
8684 -- can denote a discriminant.
8688 -- The visible components of a class-wide type are those of
8689 -- the root type.
8699 then
8706 else
8710 Error_Msg_N
8715 else
8718 -- There may be an implicit dereference. Retrieve
8719 -- designated record type.
8723 else
8729 -- Resolution chooses the new interpretation.
8730 -- Find the component with the right name.
8735 loop
8756 else
8757 -- Resolve prefix with its type
8762 -- Generate cross-reference. We needed to wait until full overloading
8763 -- resolution was complete to do this, since otherwise we can't tell if
8764 -- we are an lvalue or not.
8768 else
8772 -- If prefix is an access type, the node will be transformed into an
8773 -- explicit dereference during expansion. The type of the node is the
8774 -- designated type of that of the prefix.
8779 else
8790 and then not Init_Component
8791 then
8799 -- If the prefix is a record conversion, this may be a renamed
8800 -- discriminant whose bounds differ from those of the original
8801 -- one, so we must ensure that a range check is performed.
8806 then
8810 -- Note: No Eval processing is required, because the prefix is of a
8811 -- record type, or protected type, and neither can possibly be static.
8813 -- If the array type is atomic, and is packed, and we are in a left side
8814 -- context, then this is worth a warning, since we have a situation
8815 -- where the access to the component may cause extra read/writes of the
8816 -- atomic array object, which could be considered unexpected.
8824 then
8825 Error_Msg_N
8827 Error_Msg_N
8834 -------------------
8835 -- Resolve_Shift --
8836 -------------------
8843 begin
8844 -- We do the resolution using the base type, because intermediate values
8845 -- in expressions always are of the base type, not a subtype of it.
8858 ---------------------------
8859 -- Resolve_Short_Circuit --
8860 ---------------------------
8867 begin
8871 -- Check for issuing warning for always False assert/check, this happens
8872 -- when assertions are turned off, in which case the pragma Assert/Check
8873 -- was transformed into:
8875 -- if False and then <condition> then ...
8877 -- and we detect this pattern
8879 if Warn_On_Assertion_Failure
8886 then
8887 declare
8890 begin
8893 then
8894 -- Don't want to warn if original condition is explicit False
8896 declare
8898 Original_Node
8899 (Expression
8901 begin
8904 then
8906 else
8907 -- Issue warning. We do not want the deletion of the
8908 -- IF/AND-THEN to take this message with it. We achieve
8909 -- this by making sure that the expanded code points to
8910 -- the Sloc of the expression, not the original pragma.
8912 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
8913 -- The source location of the expression is not usually
8914 -- the best choice here. For example, it gets located on
8915 -- the last AND keyword in a chain of boolean expressiond
8916 -- AND'ed together. It is best to put the message on the
8917 -- first character of the assertion, which is the effect
8918 -- of the First_Node call here.
8920 Error_Msg_F
8922 Expression
8927 -- Similar processing for Check pragma
8931 then
8932 -- Don't want to warn if original condition is explicit False
8934 declare
8936 Original_Node
8937 (Expression
8940 begin
8943 then
8946 -- Post warning
8948 else
8949 -- Again use Error_Msg_F rather than Error_Msg_N, see
8950 -- comment above for an explanation of why we do this.
8952 Error_Msg_F
8954 Expression
8962 -- Continue with processing of short circuit
8971 -------------------
8972 -- Resolve_Slice --
8973 -------------------
8981 begin
8984 -- Use the context type to select the prefix that yields the correct
8985 -- array type.
8987 declare
8994 begin
9002 then
9010 else
9015 else
9026 else
9036 -- If the prefix is an access to an unconstrained array, we must use
9037 -- the actual subtype of the object to perform the index checks. The
9038 -- object denoted by the prefix is implicit in the node, so we build
9039 -- an explicit representation for it in order to compute the actual
9040 -- subtype.
9045 declare
9049 begin
9060 then
9063 -- If the name is a selected component that depends on discriminants,
9064 -- build an actual subtype for it. This can happen only when the name
9065 -- itself is overloaded; otherwise the actual subtype is created when
9066 -- the selected component is analyzed.
9069 and then Full_Analysis
9071 then
9072 declare
9075 begin
9080 -- Maybe this should just be "else", instead of checking for the
9081 -- specific case of slice??? This is needed for the case where the
9082 -- prefix is an Image attribute, which gets expanded to a slice, and so
9083 -- has a constrained subtype which we want to use for the slice range
9084 -- check applied below (the range check won't get done if the
9085 -- unconstrained subtype of the 'Image is used).
9091 -- If name was overloaded, set slice type correctly now
9095 -- If the range is specified by a subtype mark, no resolution is
9096 -- necessary. Else resolve the bounds, and apply needed checks.
9101 else
9109 -- Ensure that side effects in the bounds are properly handled
9114 -- Do not apply the range check to nodes associated with the
9115 -- frontend expansion of the dispatch table. We first check
9116 -- if Ada.Tags is already loaded to avoid the addition of an
9117 -- undesired dependence on such run-time unit.
9119 if not Tagged_Type_Expansion
9120 or else not
9126 then
9134 -- Check bad use of type with predicates
9137 Bad_Predicated_Subtype_Use
9141 -- Otherwise here is where we check suspicious indexes
9152 ----------------------------
9153 -- Resolve_String_Literal --
9154 ----------------------------
9165 begin
9166 -- For a string appearing in a concatenation, defer creation of the
9167 -- string_literal_subtype until the end of the resolution of the
9168 -- concatenation, because the literal may be constant-folded away. This
9169 -- is a useful optimization for long concatenation expressions.
9171 -- If the string is an aggregate built for a single character (which
9172 -- happens in a non-static context) or a is null string to which special
9173 -- checks may apply, we build the subtype. Wide strings must also get a
9174 -- string subtype if they come from a one character aggregate. Strings
9175 -- generated by attributes might be static, but it is often hard to
9176 -- determine whether the enclosing context is static, so we generate
9177 -- subtypes for them as well, thus losing some rarer optimizations ???
9178 -- Same for strings that come from a static conversion.
9180 Need_Check :=
9189 -- If the resolving type is itself a string literal subtype, we can just
9190 -- reuse it, since there is no point in creating another.
9196 and then not Need_Check
9198 N_Attribute_Reference,
9199 N_Qualified_Expression,
9200 N_Type_Conversion)
9201 then
9204 -- Otherwise we must create a string literal subtype. Note that the
9205 -- whole idea of string literal subtypes is simply to avoid the need
9206 -- for building a full fledged array subtype for each literal.
9208 else
9214 or else Need_Check
9215 then
9222 then
9228 -- The validity of a null string has been checked in the call to
9229 -- Eval_String_Literal.
9234 -- Always accept string literal with component type Any_Character, which
9235 -- occurs in error situations and in comparisons of literals, both of
9236 -- which should accept all literals.
9241 -- If the type is bit-packed, then we always transform the string
9242 -- literal into a full fledged aggregate.
9247 -- Deal with cases of Wide_Wide_String, Wide_String, and String
9249 else
9250 -- For Standard.Wide_Wide_String, or any other type whose component
9251 -- type is Standard.Wide_Wide_Character, we know that all the
9252 -- characters in the string must be acceptable, since the parser
9253 -- accepted the characters as valid character literals.
9258 -- For the case of Standard.String, or any other type whose component
9259 -- type is Standard.Character, we must make sure that there are no
9260 -- wide characters in the string, i.e. that it is entirely composed
9261 -- of characters in range of type Character.
9263 -- If the string literal is the result of a static concatenation, the
9264 -- test has already been performed on the components, and need not be
9265 -- repeated.
9269 then
9273 -- If we are out of range, post error. This is one of the
9274 -- very few places that we place the flag in the middle of
9275 -- a token, right under the offending wide character. Not
9276 -- quite clear if this is right wrt wide character encoding
9277 -- sequences, but it's only an error message!
9279 Error_Msg
9286 -- For the case of Standard.Wide_String, or any other type whose
9287 -- component type is Standard.Wide_Character, we must make sure that
9288 -- there are no wide characters in the string, i.e. that it is
9289 -- entirely composed of characters in range of type Wide_Character.
9291 -- If the string literal is the result of a static concatenation,
9292 -- the test has already been performed on the components, and need
9293 -- not be repeated.
9297 then
9301 -- If we are out of range, post error. This is one of the
9302 -- very few places that we place the flag in the middle of
9303 -- a token, right under the offending wide character.
9305 -- This is not quite right, because characters in general
9306 -- will take more than one character position ???
9308 Error_Msg
9315 -- If the root type is not a standard character, then we will convert
9316 -- the string into an aggregate and will let the aggregate code do
9317 -- the checking. Standard Wide_Wide_Character is also OK here.
9319 else
9323 -- See if the component type of the array corresponding to the string
9324 -- has compile time known bounds. If yes we can directly check
9325 -- whether the evaluation of the string will raise constraint error.
9326 -- Otherwise we need to transform the string literal into the
9327 -- corresponding character aggregate and let the aggregate code do
9328 -- the checking.
9332 -- Check for the case of full range, where we are definitely OK
9338 -- Here the range is not the complete base type range, so check
9340 declare
9348 begin
9351 then
9357 then
9358 Apply_Compile_Time_Constraint_Error
9370 -- If we got here we meed to transform the string literal into the
9371 -- equivalent qualified positional array aggregate. This is rather
9372 -- heavy artillery for this situation, but it is hard work to avoid.
9374 declare
9379 begin
9380 -- Build the character literals, we give them source locations that
9381 -- correspond to the string positions, which is a bit tricky given
9382 -- the possible presence of wide character escape sequences.
9396 -- Should we have a call to Skip_Wide here ???
9398 -- ??? else
9399 -- Skip_Wide (P);
9407 Expression =>
9414 -----------------------------
9415 -- Resolve_Subprogram_Info --
9416 -----------------------------
9419 begin
9423 -----------------------------
9424 -- Resolve_Type_Conversion --
9425 -----------------------------
9437 -- Set to False to suppress cases where we want to suppress the test
9438 -- for redundancy to avoid possible false positives on this warning.
9440 begin
9441 if not Conv_OK
9443 then
9447 -- If the Operand Etype is Universal_Fixed, then the conversion is
9448 -- never redundant. We need this check because by the time we have
9449 -- finished the rather complex transformation, the conversion looks
9450 -- redundant when it is not.
9455 -- If the operand is marked as Any_Fixed, then special processing is
9456 -- required. This is also a case where we suppress the test for a
9457 -- redundant conversion, since most certainly it is not redundant.
9462 -- Mixed-mode operation involving a literal. Context must be a fixed
9463 -- type which is applied to the literal subsequently.
9471 or else
9473 then
9474 -- Return if expression is ambiguous
9479 -- If nothing else, the available fixed type is Duration
9481 else
9485 -- Resolve the real operand with largest available precision
9489 else
9495 -- If the operand is a literal (it could be a non-static and
9496 -- illegal exponentiation) check whether the use of Duration
9497 -- is potentially inaccurate.
9502 then
9503 Error_Msg_N
9506 Rop);
9507 Error_Msg_N
9514 then
9517 else
9526 -- In SPARK, a type conversion between array types should be restricted
9527 -- to types which have matching static bounds.
9529 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9530 -- operation if not needed.
9537 then
9538 Check_SPARK_Restriction
9542 -- In formal mode, the operand of an ancestor type conversion must be an
9543 -- object (not an expression).
9551 then
9557 -- Note: we do the Eval_Type_Conversion call before applying the
9558 -- required checks for a subtype conversion. This is important, since
9559 -- both are prepared under certain circumstances to change the type
9560 -- conversion to a constraint error node, but in the case of
9561 -- Eval_Type_Conversion this may reflect an illegality in the static
9562 -- case, and we would miss the illegality (getting only a warning
9563 -- message), if we applied the type conversion checks first.
9567 -- Even when evaluation is not possible, we may be able to simplify the
9568 -- conversion or its expression. This needs to be done before applying
9569 -- checks, since otherwise the checks may use the original expression
9570 -- and defeat the simplifications. This is specifically the case for
9571 -- elimination of the floating-point Truncation attribute in
9572 -- float-to-int conversions.
9576 -- If after evaluation we still have a type conversion, then we may need
9577 -- to apply checks required for a subtype conversion.
9579 -- Skip these type conversion checks if universal fixed operands
9580 -- operands involved, since range checks are handled separately for
9581 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
9587 then
9591 -- Issue warning for conversion of simple object to its own type. We
9592 -- have to test the original nodes, since they may have been rewritten
9593 -- by various optimizations.
9597 -- Here we test for a redundant conversion if the warning mode is
9598 -- active (and was not locally reset), and we have a type conversion
9599 -- from source not appearing in a generic instance.
9601 if Test_Redundant
9604 and then not In_Instance
9605 then
9609 -- If the node is part of a larger expression, the Target_Type
9610 -- may not be the original type of the node if the context is a
9611 -- condition. Recover original type to see if conversion is needed.
9615 then
9619 -- If we have an entity name, then give the warning if the entity
9620 -- is the right type, or if it is a loop parameter covered by the
9621 -- original type (that's needed because loop parameters have an
9622 -- odd subtype coming from the bounds).
9625 and then
9627 or else
9631 -- If not an entity, then type of expression must match
9634 then
9635 -- One more check, do not give warning if the analyzed conversion
9636 -- has an expression with non-static bounds, and the bounds of the
9637 -- target are static. This avoids junk warnings in cases where the
9638 -- conversion is necessary to establish staticness, for example in
9639 -- a case statement.
9643 then
9646 -- Finally, if this type conversion occurs in a context requiring
9647 -- a prefix, and the expression is a qualified expression then the
9648 -- type conversion is not redundant, since a qualified expression
9649 -- is not a prefix, whereas a type conversion is. For example, "X
9650 -- := T'(Funx(...)).Y;" is illegal because a selected component
9651 -- requires a prefix, but a type conversion makes it legal: "X :=
9652 -- T(T'(Funx(...))).Y;"
9654 -- In Ada 2012, a qualified expression is a name, so this idiom is
9655 -- no longer needed, but we still suppress the warning because it
9656 -- seems unfriendly for warnings to pop up when you switch to the
9657 -- newer language version.
9661 N_Indexed_Component,
9662 N_Selected_Component,
9663 N_Slice,
9664 N_Explicit_Dereference)
9665 then
9668 -- Never warn on conversion to Long_Long_Integer'Base since
9669 -- that is most likely an artifact of the extended overflow
9670 -- checking and comes from complex expanded code.
9675 -- Here we give the redundant conversion warning. If it is an
9676 -- entity, give the name of the entity in the message. If not,
9677 -- just mention the expression.
9679 else
9682 Error_Msg_NE -- CODEFIX
9685 else
9686 Error_Msg_NE
9694 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
9695 -- No need to perform any interface conversion if the type of the
9696 -- expression coincides with the target type.
9699 and then Full_Expander_Active
9701 then
9702 declare
9706 begin
9718 -- Conversion from interface type
9722 -- Ada 2005 (AI-217): Handle entities from limited views
9726 Error_Msg_NE -- CODEFIX
9729 Error_Msg_N
9731 N);
9734 and then not
9737 then
9739 Error_Msg_NE -- CODEFIX
9742 Error_Msg_N
9744 N);
9746 else
9750 -- Conversion to interface type
9754 -- Handle subtypes
9760 if not Interface_Present_In_Ancestor
9763 then
9766 -- The static analysis is not enough to know if the
9767 -- interface is implemented or not. Hence we must pass
9768 -- the work to the expander to generate code to evaluate
9769 -- the conversion at run time.
9773 else
9776 Error_Msg_N
9781 else
9788 -- Ada 2012: if target type has predicates, the result requires a
9789 -- predicate check. If the context is a call to another predicate
9790 -- check we must prevent infinite recursion.
9796 then
9799 else
9805 ----------------------
9806 -- Resolve_Unary_Op --
9807 ----------------------
9816 begin
9819 Check_SPARK_Restriction
9823 -- Deal with intrinsic unary operators
9829 then
9834 -- Deal with universal cases
9837 or else
9839 then
9846 -- Generate warning for expressions like abs (x mod 2)
9848 if Warn_On_Redundant_Constructs
9850 then
9854 Error_Msg_N -- CODEFIX
9859 -- Deal with reference generation
9866 -- Set overflow checking bit. Much cleverer code needed here eventually
9867 -- and perhaps the Resolve routines should be separated for the various
9868 -- arithmetic operations, since they will need different processing ???
9876 -- Generate warning for expressions like -5 mod 3 for integers. No need
9877 -- to worry in the floating-point case, since parens do not affect the
9878 -- result so there is no point in giving in a warning.
9880 declare
9889 begin
9890 if Warn_On_Questionable_Missing_Parens
9894 then
9897 -- We are looking for cases where the right operand is not
9898 -- parenthesized, and is a binary operator, multiply, divide, or
9899 -- mod. These are the cases where the grouping can affect results.
9903 then
9904 -- For mod, we always give the warning, since the value is
9905 -- affected by the parenthesization (e.g. (-5) mod 315 /=
9906 -- -(5 mod 315)). But for the other cases, the only concern is
9907 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
9908 -- overflows, but (-2) * 64 does not). So we try to give the
9909 -- message only when overflow is possible.
9913 then
9918 else
9924 else
9928 -- Note that the test below is deliberately excluding the
9929 -- largest negative number, since that is a potentially
9930 -- troublesome case (e.g. -2 * x, where the result is the
9931 -- largest negative integer has an overflow with 2 * x).
9938 -- For the multiplication case, the only case we have to worry
9939 -- about is when (-a)*b is exactly the largest negative number
9940 -- so that -(a*b) can cause overflow. This can only happen if
9941 -- a is a power of 2, and more generally if any operand is a
9942 -- constant that is not a power of 2, then the parentheses
9943 -- cannot affect whether overflow occurs. We only bother to
9944 -- test the left most operand
9946 -- Loop looking at left operands for one that has known value
9953 -- Operand value of 0 or 1 skips warning
9958 -- Otherwise check power of 2, if power of 2, warn, if
9959 -- anything else, skip warning.
9961 else
9965 else
9974 -- Keep looking at left operands
9979 -- For rem or "/" we can only have a problematic situation
9980 -- if the divisor has a value of minus one or one. Otherwise
9981 -- overflow is impossible (divisor > 1) or we have a case of
9982 -- division by zero in any case.
9987 then
9991 -- If we fall through warning should be issued
9993 Error_Msg_N
10000 ----------------------------------
10001 -- Resolve_Unchecked_Expression --
10002 ----------------------------------
10004 procedure Resolve_Unchecked_Expression
10007 is
10008 begin
10013 ---------------------------------------
10014 -- Resolve_Unchecked_Type_Conversion --
10015 ---------------------------------------
10017 procedure Resolve_Unchecked_Type_Conversion
10020 is
10026 begin
10027 -- Resolve operand using its own type
10034 ------------------------------
10035 -- Rewrite_Operator_As_Call --
10036 ------------------------------
10043 begin
10050 New_N :=
10061 ------------------------------
10062 -- Rewrite_Renamed_Operator --
10063 ------------------------------
10065 procedure Rewrite_Renamed_Operator
10069 is
10074 begin
10075 -- Rewrite the operator node using the real operator, not its renaming.
10076 -- Exclude user-defined intrinsic operations of the same name, which are
10077 -- treated separately and rewritten as calls.
10086 -- Indicate that both the original entity and its renaming are
10087 -- referenced at this point.
10098 -- If the context type is private, add the appropriate conversions so
10099 -- that the operator is applied to the full view. This is done in the
10100 -- routines that resolve intrinsic operators.
10104 then
10106 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
10107 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
10120 -- Operator renames a user-defined operator of the same name. Use the
10121 -- original operator in the node, which is the one Gigi knows about.
10128 -----------------------
10129 -- Set_Slice_Subtype --
10130 -----------------------
10132 -- Build an implicit subtype declaration to represent the type delivered by
10133 -- the slice. This is an abbreviated version of an array subtype. We define
10134 -- an index subtype for the slice, using either the subtype name or the
10135 -- discrete range of the slice. To be consistent with index usage elsewhere
10136 -- we create a list header to hold the single index. This list is not
10137 -- otherwise attached to the syntax tree.
10148 begin
10152 else
10153 -- We force the evaluation of a range. This is definitely needed in
10154 -- the renamed case, and seems safer to do unconditionally. Note in
10155 -- any case that since we will create and insert an Itype referring
10156 -- to this range, we must make sure any side effect removal actions
10157 -- are inserted before the Itype definition.
10168 -- Take a new copy of Drange (where bounds have been rewritten to
10169 -- reference side-effect-free names). Using a separate tree ensures
10170 -- that further expansion (e.g. while rewriting a slice assignment
10171 -- into a FOR loop) does not attempt to remove side effects on the
10172 -- bounds again (which would cause the bounds in the index subtype
10173 -- definition to refer to temporaries before they are defined) (the
10174 -- reason is that some names are considered side effect free here
10175 -- for the subtype, but not in the context of a loop iteration
10176 -- scheme).
10197 -- The Etype of the existing Slice node is reset to this slice subtype.
10198 -- Its bounds are obtained from its first index.
10202 -- For packed slice subtypes, freeze immediately (except in the case of
10203 -- being in a "spec expression" where we never freeze when we first see
10204 -- the expression).
10209 -- For all other cases insert an itype reference in the slice's actions
10210 -- so that the itype is frozen at the proper place in the tree (i.e. at
10211 -- the point where actions for the slice are analyzed). Note that this
10212 -- is different from freezing the itype immediately, which might be
10213 -- premature (e.g. if the slice is within a transient scope). This needs
10214 -- to be done only if expansion is enabled.
10221 --------------------------------
10222 -- Set_String_Literal_Subtype --
10223 --------------------------------
10231 begin
10243 -- The low bound is set from the low bound of the corresponding index
10244 -- type. Note that we do not store the high bound in the string literal
10245 -- subtype, but it can be deduced if necessary from the length and the
10246 -- low bound.
10251 -- If the lower bound is not static we create a range for the string
10252 -- literal, using the index type and the known length of the literal.
10253 -- The index type is not necessarily Positive, so the upper bound is
10254 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
10256 else
10257 declare
10263 Prefix =>
10267 Left_Opnd =>
10270 Prefix =>
10272 Expressions =>
10274 Right_Opnd =>
10283 begin
10285 Set_String_Literal_Low_Bound
10288 else
10289 -- If the index type is an enumeration type, build bounds
10290 -- expression with attributes.
10292 Set_String_Literal_Low_Bound
10296 Prefix =>
10303 -- Build bona fide subtype for the string, and wrap it in an
10304 -- unchecked conversion, because the backend expects the
10305 -- String_Literal_Subtype to have a static lower bound.
10307 Index_Subtype :=
10314 -- In the context, the Index_Type may already have a constraint,
10315 -- so use common base type on string subtype. The base type may
10316 -- be used when generating attributes of the string, for example
10317 -- in the context of a slice assignment.
10342 ------------------------------
10343 -- Simplify_Type_Conversion --
10344 ------------------------------
10347 begin
10349 declare
10354 begin
10356 and then
10363 -- Special processing required if the conversion is the expression
10364 -- of a Truncation attribute reference. In this case we replace:
10366 -- ityp (ftyp'Truncation (x))
10368 -- by
10370 -- ityp (x)
10372 -- with the Float_Truncate flag set, which is more efficient.
10374 then
10383 -----------------------------
10384 -- Unique_Fixed_Point_Type --
10385 -----------------------------
10394 -- Give error messages for true ambiguity. Messages are posted on node
10395 -- N, and entities T1, T2 are the possible interpretations.
10397 -----------------------
10398 -- Fixed_Point_Error --
10399 -----------------------
10402 begin
10408 -- Start of processing for Unique_Fixed_Point_Type
10410 begin
10411 -- The operations on Duration are visible, so Duration is always a
10412 -- possible interpretation.
10416 -- Look for fixed-point types in enclosing scopes
10425 then
10427 Fixed_Point_Error;
10429 else
10440 -- Look for visible fixed type declarations in the context
10451 then
10453 Fixed_Point_Error;
10455 else
10469 else
10476 ----------------------
10477 -- Valid_Conversion --
10478 ----------------------
10480 function Valid_Conversion
10485 is
10489 function Conversion_Check
10492 -- Little routine to post Msg if Valid is False, returns Valid value
10494 -- The following are badly named, this kind of overloading is actively
10495 -- confusing in reading code, please rename to something like
10496 -- Error_Msg_N_If_Reporting ???
10499 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
10501 procedure Error_Msg_NE
10505 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
10507 function Valid_Tagged_Conversion
10510 -- Specifically test for validity of tagged conversions
10513 -- Check index and component conformance, and accessibility levels if
10514 -- the component types are anonymous access types (Ada 2005).
10516 ----------------------
10517 -- Conversion_Check --
10518 ----------------------
10520 function Conversion_Check
10523 is
10524 begin
10525 if not Valid
10527 -- A generic unit has already been analyzed and we have verified
10528 -- that a particular conversion is OK in that context. Since the
10529 -- instance is reanalyzed without relying on the relationships
10530 -- established during the analysis of the generic, it is possible
10531 -- to end up with inconsistent views of private types. Do not emit
10532 -- the error message in such cases. The rest of the machinery in
10533 -- Valid_Conversion still ensures the proper compatibility of
10534 -- target and operand types.
10536 and then not In_Instance
10537 then
10544 -----------------
10545 -- Error_Msg_N --
10546 -----------------
10549 begin
10555 ------------------
10556 -- Error_Msg_NE --
10557 ------------------
10559 procedure Error_Msg_NE
10563 is
10564 begin
10570 ----------------------------
10571 -- Valid_Array_Conversion --
10572 ----------------------------
10575 is
10590 begin
10591 -- Error if wrong number of dimensions
10593 if
10595 then
10596 Error_Msg_N
10600 -- Number of dimensions matches
10602 else
10603 -- Loop through indexes of the two arrays
10611 -- Error if index types are incompatible
10617 then
10618 Error_Msg_N
10620 Operand);
10628 -- If component types have same base type, all set
10633 -- Here if base types of components are not the same. The only
10634 -- time this is allowed is if we have anonymous access types.
10636 -- The conversion of arrays of anonymous access types can lead
10637 -- to dangling pointers. AI-392 formalizes the accessibility
10638 -- checks that must be applied to such conversions to prevent
10639 -- out-of-scope references.
10641 elsif Ekind_In
10643 E_Anonymous_Access_Subprogram_Type)
10645 and then
10647 then
10650 then
10652 Error_Msg_N
10655 Error_Msg_N
10657 Operand);
10664 -- Conversion not allowed because of accessibility levels
10666 else
10667 Error_Msg_N
10673 else
10677 -- All other cases where component base types do not match
10679 else
10680 Error_Msg_N
10682 Operand);
10686 -- Check that component subtypes statically match. For numeric
10687 -- types this means that both must be either constrained or
10688 -- unconstrained. For enumeration types the bounds must match.
10689 -- All of this is checked in Subtypes_Statically_Match.
10691 if not Subtypes_Statically_Match
10693 then
10694 Error_Msg_N
10703 -----------------------------
10704 -- Valid_Tagged_Conversion --
10705 -----------------------------
10707 function Valid_Tagged_Conversion
10710 is
10711 begin
10712 -- Upward conversions are allowed (RM 4.6(22))
10716 then
10719 -- Downward conversion are allowed if the operand is class-wide
10720 -- (RM 4.6(23)).
10724 then
10729 then
10730 return
10734 -- Ada 2005 (AI-251): The conversion to/from interface types is
10735 -- always valid
10740 -- If the operand is a class-wide type obtained through a limited_
10741 -- with clause, and the context includes the non-limited view, use
10742 -- it to determine whether the conversion is legal.
10748 then
10753 then
10756 else
10757 Error_Msg_NE
10764 -- Start of processing for Valid_Conversion
10766 begin
10770 declare
10778 begin
10779 -- Remove procedure calls, which syntactically cannot appear in
10780 -- this context, but which cannot be removed by type checking,
10781 -- because the context does not impose a type.
10783 -- When compiling for VMS, spurious ambiguities can be produced
10784 -- when arithmetic operations have a literal operand and return
10785 -- System.Address or a descendant of it. These ambiguities are
10786 -- otherwise resolved by the context, but for conversions there
10787 -- is no context type and the removal of the spurious operations
10788 -- must be done explicitly here.
10790 -- The node may be labelled overloaded, but still contain only one
10791 -- interpretation because others were discarded earlier. If this
10792 -- is the case, retain the single interpretation if legal.
10800 then
10801 -- More than one candidate interpretation is available
10811 then
10838 -- If the interpretation involves a standard operator, use
10839 -- the location of the type, which may be user-defined.
10843 else
10847 Error_Msg_N -- CODEFIX
10852 else
10856 Error_Msg_N -- CODEFIX
10868 -- Numeric types
10872 -- A universal fixed expression can be converted to any numeric type
10877 -- Also no need to check when in an instance or inlined body, because
10878 -- the legality has been established when the template was analyzed.
10879 -- Furthermore, numeric conversions may occur where only a private
10880 -- view of the operand type is visible at the instantiation point.
10881 -- This results in a spurious error if we check that the operand type
10882 -- is a numeric type.
10884 -- Note: in a previous version of this unit, the following tests were
10885 -- applied only for generated code (Comes_From_Source set to False),
10886 -- but in fact the test is required for source code as well, since
10887 -- this situation can arise in source code.
10892 -- Otherwise we need the conversion check
10894 else
10895 return Conversion_Check
10900 -- Array types
10906 then
10909 else
10913 -- Ada 2005 (AI-251): Anonymous access types where target references an
10914 -- interface type.
10917 E_Anonymous_Access_Type)
10919 then
10920 -- Check the static accessibility rule of 4.6(17). Note that the
10921 -- check is not enforced when within an instance body, since the
10922 -- RM requires such cases to be caught at run time.
10924 -- If the operand is a rewriting of an allocator no check is needed
10925 -- because there are no accessibility issues.
10933 then
10934 -- In an instance, this is a run-time check, but one we know
10935 -- will fail, so generate an appropriate warning. The raise
10936 -- will be generated by Expand_N_Type_Conversion.
10939 Error_Msg_N
10941 Operand);
10942 Error_Msg_N
10945 else
10946 Error_Msg_N
10948 Operand);
10952 -- Special accessibility checks are needed in the case of access
10953 -- discriminants declared for a limited type.
10957 then
10958 -- When the operand is a selected access discriminant the check
10959 -- needs to be made against the level of the object denoted by
10960 -- the prefix of the selected name (Object_Access_Level handles
10961 -- checking the prefix of the operand for this case).
10966 then
10967 -- In an instance, this is a run-time check, but one we know
10968 -- will fail, so generate an appropriate warning. The raise
10969 -- will be generated by Expand_N_Type_Conversion.
10972 Error_Msg_N
10975 Error_Msg_N
10977 else
10978 Error_Msg_N
10985 -- The case of a reference to an access discriminant from
10986 -- within a limited type declaration (which will appear as
10987 -- a discriminal) is always illegal because the level of the
10988 -- discriminant is considered to be deeper than any (nameable)
10989 -- access type.
10993 and then
10996 then
10997 Error_Msg_N
10999 Operand);
11007 -- General and anonymous access types
11010 E_Anonymous_Access_Type)
11011 and then
11012 Conversion_Check
11014 and then not
11016 E_Access_Protected_Subprogram_Type),
11018 then
11021 then
11022 Error_Msg_N
11027 -- Check the static accessibility rule of 4.6(17). Note that the
11028 -- check is not enforced when within an instance body, since the RM
11029 -- requires such cases to be caught at run time.
11034 N_Object_Declaration
11035 then
11036 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
11037 -- conversions from an anonymous access type to a named general
11038 -- access type. Such conversions are not allowed in the case of
11039 -- access parameters and stand-alone objects of an anonymous
11040 -- access type. The implicit conversion case is recognized by
11041 -- testing that Comes_From_Source is False and that it's been
11042 -- rewritten. The Comes_From_Source test isn't sufficient because
11043 -- nodes in inlined calls to predefined library routines can have
11044 -- Comes_From_Source set to False. (Is there a better way to test
11045 -- for implicit conversions???)
11052 then
11055 -- Implicit conversions aren't allowed for objects of an
11056 -- anonymous access type, since such objects have nonstatic
11057 -- levels in Ada 2012.
11060 N_Object_Declaration
11061 then
11062 Error_Msg_N
11067 -- Implicit conversions aren't allowed for anonymous access
11068 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
11069 -- is done to exclude anonymous access results.
11073 N_Function_Specification,
11074 N_Procedure_Specification)
11075 then
11076 Error_Msg_N
11081 -- This is a case where there's an enclosing object whose
11082 -- to which the "statically deeper than" relationship does
11083 -- not apply (such as an access discriminant selected from
11084 -- a dereference of an access parameter).
11088 then
11089 Error_Msg_N
11094 -- In other cases, the level of the operand's type must be
11095 -- statically less deep than that of the target type, else
11096 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
11100 then
11101 Error_Msg_N
11110 then
11111 -- In an instance, this is a run-time check, but one we know
11112 -- will fail, so generate an appropriate warning. The raise
11113 -- will be generated by Expand_N_Type_Conversion.
11116 Error_Msg_N
11118 Operand);
11119 Error_Msg_N
11122 else
11123 -- Avoid generation of spurious error message
11126 Error_Msg_N
11128 Operand);
11134 -- Special accessibility checks are needed in the case of access
11135 -- discriminants declared for a limited type.
11139 then
11140 -- When the operand is a selected access discriminant the check
11141 -- needs to be made against the level of the object denoted by
11142 -- the prefix of the selected name (Object_Access_Level handles
11143 -- checking the prefix of the operand for this case).
11148 then
11149 -- In an instance, this is a run-time check, but one we know
11150 -- will fail, so generate an appropriate warning. The raise
11151 -- will be generated by Expand_N_Type_Conversion.
11154 Error_Msg_N
11157 Error_Msg_N
11159 Operand);
11161 else
11162 Error_Msg_N
11169 -- The case of a reference to an access discriminant from
11170 -- within a limited type declaration (which will appear as
11171 -- a discriminal) is always illegal because the level of the
11172 -- discriminant is considered to be deeper than any (nameable)
11173 -- access type.
11176 and then
11179 then
11180 Error_Msg_N
11182 Operand);
11188 -- In the presence of limited_with clauses we have to use non-limited
11189 -- views, if available.
11193 -- Helper function to handle limited views
11195 --------------------------
11196 -- Full_Designated_Type --
11197 --------------------------
11202 begin
11203 -- Handle the limited view of a type
11208 then
11210 else
11215 -- Local Declarations
11223 -- Start of processing for Check_Limited
11225 begin
11229 else
11231 Error_Msg_NE
11236 -- Ada 2005 AI-384: legality rule is symmetric in both
11237 -- designated types. The conversion is legal (with possible
11238 -- constraint check) if either designated type is
11239 -- unconstrained.
11242 or else
11244 and then
11247 then
11248 -- Special case, if Value_Size has been used to make the
11249 -- sizes different, the conversion is not allowed even
11250 -- though the subtypes statically match.
11255 then
11256 Error_Msg_NE
11259 Error_Msg_NE
11264 -- Normal case where conversion is allowed
11266 else
11270 else
11271 Error_Msg_NE
11279 -- Access to subprogram types. If the operand is an access parameter,
11280 -- the type has a deeper accessibility that any master, and cannot be
11281 -- assigned. We must make an exception if the conversion is part of an
11282 -- assignment and the target is the return object of an extended return
11283 -- statement, because in that case the accessibility check takes place
11284 -- after the return.
11288 then
11292 and then
11296 then
11297 Error_Msg_N
11299 Operand);
11300 Error_Msg_N
11303 Operand);
11305 Error_Msg_NE
11310 -- Check that the designated types are subtype conformant
11316 -- Check the static accessibility rule of 4.6(20)
11320 then
11321 Error_Msg_N
11323 Operand);
11325 -- Check that if the operand type is declared in a generic body,
11326 -- then the target type must be declared within that same body
11327 -- (enforces last sentence of 4.6(20)).
11330 declare
11336 begin
11343 Error_Msg_N
11352 -- Remote subprogram access types
11356 then
11357 -- It is valid to convert from one RAS type to another provided
11358 -- that their specification statically match.
11360 Check_Subtype_Conformant
11363 Old_Id =>
11365 Err_Loc =>
11366 N);
11369 -- If it was legal in the generic, it's legal in the instance
11374 -- If both are tagged types, check legality of view conversions
11377 and then
11379 then
11382 -- Types derived from the same root type are convertible
11387 -- In an instance or an inlined body, there may be inconsistent views of
11388 -- the same type, or of types derived from a common root.
11391 and then
11394 then
11397 -- Special check for common access type error case
11401 then
11403 Error_Msg_NE -- CODEFIX
11407 else