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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) 1992-2018, 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 ------------------------------------------------------------------------------
86 -----------------------
87 -- Local Subprograms --
88 -----------------------
90 -- Second pass (top-down) type checking and overload resolution procedures
91 -- Typ is the type required by context. These procedures propagate the
92 -- type information recursively to the descendants of N. If the node is not
93 -- overloaded, its Etype is established in the first pass. If overloaded,
94 -- the Resolve routines set the correct type. For arithmetic operators, the
95 -- Etype is the base type of the context.
97 -- Note that Resolve_Attribute is separated off in Sem_Attr
100 -- Enforce the restrictions on the use of discriminants when constraining
101 -- a component of a discriminated type (record or concurrent type).
104 -- Given a node for an operator associated with type T, check that the
105 -- operator is visible. Operators all of whose operands are universal must
106 -- be checked for visibility during resolution because their type is not
107 -- determinable based on their operands.
109 procedure Check_Fully_Declared_Prefix
112 -- Check that the type of the prefix of a dereference is not incomplete
115 -- Given a call node, N, which is known to occur immediately within the
116 -- subprogram being called, determines whether it is a detectable case of
117 -- an infinite recursion, and if so, outputs appropriate messages. Returns
118 -- True if an infinite recursion is detected, and False otherwise.
121 -- N is the node for a logical operator. If the operator is predefined, and
122 -- the root type of the operands is Standard.Boolean, then a check is made
123 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
124 -- the style check for Style_Check_Boolean_And_Or.
127 -- N is either an indexed component or a selected component. This function
128 -- returns true if the prefix refers to an object that has an address
129 -- clause (the case in which we may want to issue a warning).
132 -- Determine whether E is an access type declared by an access declaration,
133 -- and not an (anonymous) allocator type.
136 -- Utility to check whether the entity for an operator is a predefined
137 -- operator, in which case the expression is left as an operator in the
138 -- tree (else it is rewritten into a call). An instance of an intrinsic
139 -- conversion operation may be given an operator name, but is not treated
140 -- like an operator. Note that an operator that is an imported back-end
141 -- builtin has convention Intrinsic, but is expected to be rewritten into
142 -- a call, so such an operator is not treated as predefined by this
143 -- predicate.
145 procedure Preanalyze_And_Resolve
149 -- Subsidiary of public versions of Preanalyze_And_Resolve.
152 -- If a default expression in entry call N depends on the discriminants
153 -- of the task, it must be replaced with a reference to the discriminant
154 -- of the task being called.
156 procedure Resolve_Op_Concat_Arg
161 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
162 -- concatenation operator. The operand is either of the array type or of
163 -- the component type. If the operand is an aggregate, and the component
164 -- type is composite, this is ambiguous if component type has aggregates.
167 -- Does the first part of the work of Resolve_Op_Concat
170 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
171 -- 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 arithmetic unary operators
238 -- If an operator node resolves to a call to a user-defined operator,
239 -- rewrite the node as a function call.
241 procedure Make_Call_Into_Operator
245 -- Inverse transformation: if an operator is given in functional notation,
246 -- then after resolving the node, transform into an operator node, so that
247 -- operands are resolved properly. Recall that predefined operators do not
248 -- have a full signature and special resolution rules apply.
250 procedure Rewrite_Renamed_Operator
254 -- An operator can rename another, e.g. in an instantiation. In that
255 -- case, the proper operator node must be constructed and resolved.
258 -- The String_Literal_Subtype is built for all strings that are not
259 -- operands of a static concatenation operation. If the argument is not
260 -- a N_String_Literal node, then the call has no effect.
263 -- Build subtype of array type, with the range specified by the slice
266 -- Called after N has been resolved and evaluated, but before range checks
267 -- have been applied. Currently simplifies a combination of floating-point
268 -- to integer conversion and Rounding or Truncation attribute.
271 -- A universal_fixed expression in an universal context is unambiguous if
272 -- there is only one applicable fixed point type. Determining whether there
273 -- is only one requires a search over all visible entities, and happens
274 -- only in very pathological cases (see 6115-006).
276 -------------------------
277 -- Ambiguous_Character --
278 -------------------------
283 begin
287 -- First the ones in Standard
292 -- Include Wide_Wide_Character in Ada 2005 mode
298 -- Now any other types that match
308 -------------------------
309 -- Analyze_And_Resolve --
310 -------------------------
313 begin
319 begin
324 -- Versions with check(s) suppressed
326 procedure Analyze_And_Resolve
330 is
333 begin
335 declare
337 begin
343 else
344 declare
346 begin
354 and then Scope_Is_Transient
355 then
356 -- This can only happen if a transient scope was created for an inner
357 -- expression, which will be removed upon completion of the analysis
358 -- of an enclosing construct. The transient scope must have the
359 -- suppress status of the enclosing environment, not of this Analyze
360 -- call.
363 Scope_Suppress;
367 procedure Analyze_And_Resolve
370 is
373 begin
375 declare
377 begin
383 else
384 declare
386 begin
395 Scope_Suppress;
399 ----------------------------
400 -- Check_Discriminant_Use --
401 ----------------------------
409 begin
410 -- Any use in a spec-expression is legal
417 -- Discriminant cannot be used to constrain a scalar type
424 then
429 -- The following check catches the unusual case where a
430 -- discriminant appears within an index constraint that is part
431 -- of a larger expression within a constraint on a component,
432 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
433 -- check case of record components, and note that a similar check
434 -- should also apply in the case of discriminant constraints
435 -- below. ???
437 -- Note that the check for N_Subtype_Declaration below is to
438 -- detect the valid use of discriminants in the constraints of a
439 -- subtype declaration when this subtype declaration appears
440 -- inside the scope of a record type (which is syntactically
441 -- illegal, but which may be created as part of derived type
442 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
443 -- for more info.
447 and then not
449 and then
451 N_Subtype_Declaration)
453 then
454 Error_Msg_N
459 -- Detect a common error:
461 -- type R (D : Positive := 100) is record
462 -- Name : String (1 .. D);
463 -- end record;
465 -- The default value causes an object of type R to be allocated
466 -- with room for Positive'Last characters. The RM does not mandate
467 -- the allocation of the maximum size, but that is what GNAT does
468 -- so we should warn the programmer that there is a problem.
477 -- Return True if type T has a large enough range that any
478 -- array whose index type covered the whole range of the type
479 -- would likely raise Storage_Error.
481 ------------------------
482 -- Large_Storage_Type --
483 ------------------------
486 begin
487 -- The type is considered large if its bounds are known at
488 -- compile time and if it requires at least as many bits as
489 -- a Positive to store the possible values.
493 and then
498 -- Start of processing for Check_Large
500 begin
501 -- Check that the Disc has a large range
507 -- If the enclosing type is limited, we allocate only the
508 -- default value, not the maximum, and there is no need for
509 -- a warning.
515 -- Check that it is the high bound
519 then
523 -- Check the array allows a large range at this bound. First
524 -- find the array
538 -- Next, find the dimension
546 loop
555 -- Now, check the dimension has a large range
561 -- Warn about the danger
563 Error_Msg_N
573 -- Legal case is in index or discriminant constraint
576 N_Discriminant_Association)
577 then
579 Error_Msg_N
584 then
585 Error_Msg_N
591 -- Otherwise, context is an expression. It should not be within (i.e. a
592 -- subexpression of) a constraint for a component.
594 else
598 N_Subtype_Indication,
599 N_Entry_Declaration)
600 loop
606 -- If the discriminant is used in an expression that is a bound of a
607 -- scalar type, an Itype is created and the bounds are attached to
608 -- its range, not to the original subtype indication. Such use is of
609 -- course a double fault.
613 N_Derived_Type_Definition)
616 -- The constraint itself may be given by a subtype indication,
617 -- rather than by a more common discrete range.
620 and then
624 then
625 Error_Msg_N
631 --------------------------------
632 -- Check_For_Visible_Operator --
633 --------------------------------
636 begin
638 Error_Msg_NE -- CODEFIX
640 Error_Msg_N -- CODEFIX
645 ----------------------------------
646 -- Check_Fully_Declared_Prefix --
647 ----------------------------------
649 procedure Check_Fully_Declared_Prefix
652 is
653 begin
654 -- Check that the designated type of the prefix of a dereference is
655 -- not an incomplete type. This cannot be done unconditionally, because
656 -- dereferences of private types are legal in default expressions. This
657 -- case is taken care of in Check_Fully_Declared, called below. There
658 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
660 -- This consideration also applies to similar checks for allocators,
661 -- qualified expressions, and type conversions.
663 -- An additional exception concerns other per-object expressions that
664 -- are not directly related to component declarations, in particular
665 -- representation pragmas for tasks. These will be per-object
666 -- expressions if they depend on discriminants or some global entity.
667 -- If the task has access discriminants, the designated type may be
668 -- incomplete at the point the expression is resolved. This resolution
669 -- takes place within the body of the initialization procedure, where
670 -- the discriminant is replaced by its discriminal.
674 then
677 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
678 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
679 -- Analyze_Object_Renaming, and Freeze_Entity.
685 E_Incomplete_Type
687 then
689 else
694 ------------------------------
695 -- Check_Infinite_Recursion --
696 ------------------------------
703 -- Check whether list of actuals is identical to list of formals of
704 -- called function (which is also the enclosing scope).
706 ------------------------
707 -- Same_Argument_List --
708 ------------------------
715 begin
718 else
736 -- Start of processing for Check_Infinite_Recursion
738 begin
739 -- Special case, if this is a procedure call and is a call to the
740 -- current procedure with the same argument list, then this is for
741 -- sure an infinite recursion and we insert a call to raise SE.
745 and then Same_Argument_List
746 then
747 declare
749 begin
753 then
765 -- If not that special case, search up tree, quitting if we reach a
766 -- construct (e.g. a conditional) that tells us that this is not a
767 -- case for an infinite recursion warning.
770 loop
773 -- If no parent, then we were not inside a subprogram, this can for
774 -- example happen when processing certain pragmas in a spec. Just
775 -- return False in this case.
781 -- Done if we get to subprogram body, this is definitely an infinite
782 -- recursion case if we did not find anything to stop us.
786 -- If appearing in conditional, result is false
789 N_And_Then,
790 N_Case_Expression,
791 N_Case_Statement,
792 N_If_Expression,
793 N_If_Statement)
794 then
799 then
800 -- If the call is the expression of a return statement and the
801 -- actuals are identical to the formals, it's worth a warning.
802 -- However, we skip this if there is an immediately preceding
803 -- raise statement, since the call is never executed.
805 -- Furthermore, this corresponds to a common idiom:
807 -- function F (L : Thing) return Boolean is
808 -- begin
809 -- raise Program_Error;
810 -- return F (L);
811 -- end F;
813 -- for generating a stub function
816 and then Same_Argument_List
817 then
820 -- OK, return statement is in a statement list, look for raise
822 declare
825 begin
826 -- Skip past N_Freeze_Entity nodes generated by expansion
831 loop
835 -- If no raise statement, give warning. We look at the
836 -- original node, because in the case of "raise ... with
837 -- ...", the node has been transformed into a call.
840 and then
848 else
860 ---------------------------------------
861 -- Check_No_Direct_Boolean_Operators --
862 ---------------------------------------
865 begin
868 then
869 -- Restriction only applies to original source code
876 -- Do style check (but skip if in instance, error is on template)
885 ------------------------------
886 -- Check_Parameterless_Call --
887 ------------------------------
893 -- If the prefix is of an access_to_subprogram type, the node must be
894 -- rewritten as a call. Ditto if the prefix is overloaded and all its
895 -- interpretations are access to subprograms.
897 ---------------------------
898 -- Prefix_Is_Access_Subp --
899 ---------------------------
905 begin
906 -- If the context is an attribute reference that can apply to
907 -- functions, this is never a parameterless call (RM 4.1.4(6)).
911 Name_Code_Address,
912 Name_Access)
913 then
918 return
921 else
926 then
937 -- Start of processing for Check_Parameterless_Call
939 begin
940 -- Defend against junk stuff if errors already detected
947 then
954 -- If the context expects a value, and the name is a procedure, this is
955 -- most likely a missing 'Access. Don't try to resolve the parameterless
956 -- call, error will be caught when the outer call is analyzed.
961 and then
963 N_Function_Call,
964 N_Procedure_Call_Statement)
965 then
969 -- Rewrite as call if overloadable entity that is (or could be, in the
970 -- overloaded case) a function call. If we know for sure that the entity
971 -- is an enumeration literal, we do not rewrite it.
973 -- If the entity is the name of an operator, it cannot be a call because
974 -- operators cannot have default parameters. In this case, this must be
975 -- a string whose contents coincide with an operator name. Set the kind
976 -- of the node appropriately.
984 -- Rewrite as call if it is an explicit dereference of an expression of
985 -- a subprogram access type, and the subprogram type is not that of a
986 -- procedure or entry.
988 or else
991 -- Rewrite as call if it is a selected component which is a function,
992 -- this is the case of a call to a protected function (which may be
993 -- overloaded with other protected operations).
995 or else
998 or else
1000 E_Procedure)
1003 -- If one of the above three conditions is met, rewrite as call. Apply
1004 -- the rewriting only once.
1006 then
1009 then
1011 -- This may be a prefixed call that was not fully analyzed, e.g.
1012 -- an actual in an instance.
1017 then
1025 -- The node is the name of the parameterless call. Preserve its
1026 -- descendants, which may be complex expressions.
1030 -- If overloaded, overload set belongs to new copy
1034 -- Change node to parameterless function call (note that the
1035 -- Parameter_Associations associations field is left set to Empty,
1036 -- its normal default value since there are no parameters)
1054 --------------------------------
1055 -- Is_Atomic_Ref_With_Address --
1056 --------------------------------
1061 begin
1065 else
1066 declare
1069 begin
1077 -----------------------------
1078 -- Is_Definite_Access_Type --
1079 -----------------------------
1083 begin
1089 ----------------------
1090 -- Is_Predefined_Op --
1091 ----------------------
1094 begin
1095 -- Predefined operators are intrinsic subprograms
1101 -- A call to a back-end builtin is never a predefined operator
1112 -----------------------------
1113 -- Make_Call_Into_Operator --
1114 -----------------------------
1116 procedure Make_Call_Into_Operator
1120 is
1135 -- If the operand is not universal, and the operator is given by an
1136 -- expanded name, verify that the operand has an interpretation with a
1137 -- type defined in the given scope of the operator.
1140 -- Find a type of the given class in package Pack that contains the
1141 -- operator.
1143 ---------------------------
1144 -- Operand_Type_In_Scope --
1145 ---------------------------
1152 begin
1156 else
1170 ---------------
1171 -- Type_In_P --
1172 ---------------
1178 -- Verify that node is not part of the type declaration for the
1179 -- candidate type, which would otherwise be invisible.
1181 -------------
1182 -- In_Decl --
1183 -------------
1189 begin
1198 else
1201 loop
1204 else
1213 -- Start of processing for Type_In_P
1215 begin
1216 -- If the context type is declared in the prefix package, this is the
1217 -- desired base type.
1222 else
1236 -- Start of processing for Make_Call_Into_Operator
1238 begin
1241 -- Ensure that the corresponding operator has the same parent as the
1242 -- original call. This guarantees that parent traversals performed by
1243 -- the ABE mechanism succeed.
1247 -- Binary operator
1257 -- Unary operator
1259 else
1265 -- If the operator is denoted by an expanded name, and the prefix is
1266 -- not Standard, but the operator is a predefined one whose scope is
1267 -- Standard, then this is an implicit_operator, inserted as an
1268 -- interpretation by the procedure of the same name. This procedure
1269 -- overestimates the presence of implicit operators, because it does
1270 -- not examine the type of the operands. Verify now that the operand
1271 -- type appears in the given scope. If right operand is universal,
1272 -- check the other operand. In the case of concatenation, either
1273 -- argument can be the component type, so check the type of the result.
1274 -- If both arguments are literals, look for a type of the right kind
1275 -- defined in the given scope. This elaborate nonsense is brought to
1276 -- you courtesy of b33302a. The type itself must be frozen, so we must
1277 -- find the type of the proper class in the given scope.
1279 -- A final wrinkle is the multiplication operator for fixed point types,
1280 -- which is defined in Standard only, and not in the scope of the
1281 -- fixed point type itself.
1286 -- If this is a package renaming, get renamed entity, which will be
1287 -- the scope of the operands if operaton is type-correct.
1293 -- If the entity being called is defined in the given package, it is
1294 -- a renaming of a predefined operator, and known to be legal.
1298 then
1301 -- Visibility does not need to be checked in an instance: if the
1302 -- operator was not visible in the generic it has been diagnosed
1303 -- already, else there is an implicit copy of it in the instance.
1311 then
1316 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1317 -- available.
1322 then
1325 else
1334 and then Is_Binary
1336 then
1342 -- Verify that the scope contains a type that corresponds to
1343 -- the given literal. Optimize the case where Pack is Standard.
1364 else
1373 else
1382 then
1385 -- If the type is defined elsewhere, and the operator is not
1386 -- defined in the given scope (by a renaming declaration, e.g.)
1387 -- then this is an error as well. If an extension of System is
1388 -- present, and the type may be defined there, Pack must be
1389 -- System itself.
1396 then
1399 else
1405 then
1412 Error_Msg_NE
1417 -- Detect a mismatch between the context type and the result type
1418 -- in the named package, which is otherwise not detected if the
1419 -- operands are universal. Check is only needed if source entity is
1420 -- an operator, not a function that renames an operator.
1427 and then not In_Instance
1428 then
1431 then
1432 -- Already checked above
1436 -- Operator may be defined in an extension of System
1441 then
1444 else
1445 -- Could we use Wrong_Type here??? (this would require setting
1446 -- Etype (N) to the actual type found where Typ was expected).
1457 else
1461 -- If this is a call to a function that renames a predefined equality,
1462 -- the renaming declaration provides a type that must be used to
1463 -- resolve the operands. This must be done now because resolution of
1464 -- the equality node will not resolve any remaining ambiguity, and it
1465 -- assumes that the first operand is not overloaded.
1470 then
1478 -- Do rewrite setting Comes_From_Source on the result if the original
1479 -- call came from source. Although it is not strictly the case that the
1480 -- operator as such comes from the source, logically it corresponds
1481 -- exactly to the function call in the source, so it should be marked
1482 -- this way (e.g. to make sure that validity checks work fine).
1484 declare
1486 begin
1491 -- If this is an arithmetic operator and the result type is private,
1492 -- the operands and the result must be wrapped in conversion to
1493 -- expose the underlying numeric type and expand the proper checks,
1494 -- e.g. on division.
1498 when N_Op_Add
1499 | N_Op_Divide
1500 | N_Op_Expon
1501 | N_Op_Mod
1502 | N_Op_Multiply
1503 | N_Op_Rem
1504 | N_Op_Subtract
1505 =>
1508 when N_Op_Abs
1509 | N_Op_Minus
1510 | N_Op_Plus
1511 =>
1517 else
1521 -- If in ASIS_Mode, propagate operand types to original actuals of
1522 -- function call, which would otherwise not be fully resolved. If
1523 -- the call has already been constant-folded, nothing to do. We
1524 -- relocate the operand nodes rather than copy them, to preserve
1525 -- original_node pointers, given that the operands themselves may
1526 -- have been rewritten. If the call was itself a rewriting of an
1527 -- operator node, nothing to do.
1529 if ASIS_Mode
1532 then
1533 declare
1541 begin
1546 -- If the original call has named associations, replace the
1547 -- explicit actual parameter in the association with the proper
1548 -- resolved operand.
1553 then
1556 else
1561 else
1568 then
1571 else
1576 else
1580 else
1584 else
1594 -------------------
1595 -- Operator_Kind --
1596 -------------------
1598 function Operator_Kind
1601 is
1604 begin
1605 -- Use CASE statement or array???
1642 else
1646 -- Unary operators
1648 else
1657 else
1665 ----------------------------
1666 -- Preanalyze_And_Resolve --
1667 ----------------------------
1669 procedure Preanalyze_And_Resolve
1673 is
1677 Inside_Preanalysis_Without_Freezing;
1678 begin
1683 Inside_Preanalysis_Without_Freezing :=
1690 -- Normally, we suppress all checks for this preanalysis. There is no
1691 -- point in processing them now, since they will be applied properly
1692 -- and in the proper location when the default expressions reanalyzed
1693 -- and reexpanded later on. We will also have more information at that
1694 -- point for possible suppression of individual checks.
1696 -- However, in SPARK mode, most expansion is suppressed, and this
1697 -- later reanalysis and reexpansion may not occur. SPARK mode does
1698 -- require the setting of checking flags for proof purposes, so we
1699 -- do the SPARK preanalysis without suppressing checks.
1701 -- This special handling for SPARK mode is required for example in the
1702 -- case of Ada 2012 constructs such as quantified expressions, which are
1703 -- expanded in two separate steps.
1707 else
1711 Expander_Mode_Restore;
1716 Inside_Preanalysis_Without_Freezing :=
1720 pragma Assert
1724 ----------------------------
1725 -- Preanalyze_And_Resolve --
1726 ----------------------------
1729 begin
1733 -- Version without context type
1738 begin
1745 Expander_Mode_Restore;
1749 ------------------------------------------
1750 -- Preanalyze_With_Freezing_And_Resolve --
1751 ------------------------------------------
1753 procedure Preanalyze_With_Freezing_And_Resolve
1756 is
1757 begin
1761 ----------------------------------
1762 -- Replace_Actual_Discriminants --
1763 ----------------------------------
1770 -- Comment needed???
1772 -------------------
1773 -- Process_Discr --
1774 -------------------
1779 begin
1785 then
1801 -- Start of processing for Replace_Actual_Discriminants
1803 begin
1807 -- Allow the replacement of concurrent discriminants in GNATprove even
1808 -- though this is a light expansion activity. Note that generic units
1809 -- are not modified.
1814 else
1830 -------------
1831 -- Resolve --
1832 -------------
1848 -- Determine whether a node comes from a predefined library unit or
1849 -- Standard.
1852 -- Try and fix up a literal so that it matches its expected type. New
1853 -- literals are manufactured if necessary to avoid cascaded errors.
1856 -- Additional diagnostics when an ambiguous call has an ambiguous
1857 -- argument (typically a controlling actual).
1860 -- Called when attempt at resolving current expression fails
1862 ------------------------------------
1863 -- Comes_From_Predefined_Lib_Unit --
1864 -------------------------------------
1867 begin
1868 return
1872 --------------------
1873 -- Patch_Up_Value --
1874 --------------------
1877 begin
1894 then
1899 Char_Literal_Value =>
1915 -------------------------------
1916 -- Report_Ambiguous_Argument --
1917 -------------------------------
1924 begin
1928 then
1931 -- Could use comments on what is going on here???
1939 else
1948 -----------------------
1949 -- Resolution_Failed --
1950 -----------------------
1953 begin
1956 -- Set the type to the desired one to minimize cascaded errors. Note
1957 -- that this is an approximation and does not work in all cases.
1964 -- The caller will return without calling the expander, so we need
1965 -- to set the analyzed flag. Note that it is fine to set Analyzed
1966 -- to True even if we are in the middle of a shallow analysis,
1967 -- (see the spec of sem for more details) since this is an error
1968 -- situation anyway, and there is no point in repeating the
1969 -- analysis later (indeed it won't work to repeat it later, since
1970 -- we haven't got a clear resolution of which entity is being
1971 -- referenced.)
1977 -- Start of processing for Resolve
1979 begin
1984 -- Access attribute on remote subprogram cannot be used for a non-remote
1985 -- access-to-subprogram type.
1989 Name_Unrestricted_Access,
1990 Name_Unchecked_Access)
1996 then
1997 Error_Msg_N
2003 -- If the context is a Remote_Access_To_Subprogram, access attributes
2004 -- must be resolved with the corresponding fat pointer. There is no need
2005 -- to check for the attribute name since the return type of an
2006 -- attribute is never a remote type.
2011 then
2012 declare
2020 begin
2021 -- Check that Typ is a remote access-to-subprogram type
2025 -- Prefix (N) must statically denote a remote subprogram
2026 -- declared in a package specification.
2030 Attr = Attribute_Unrestricted_Access
2031 then
2046 or else
2048 then
2050 Error_Msg_N
2052 N);
2055 -- If we are generating code in distributed mode, perform
2056 -- semantic checks against corresponding remote entities.
2058 if Expander_Active
2060 then
2061 Check_Subtype_Conformant
2063 Old_Id => Designated_Type
2089 then
2094 -- Return if already analyzed
2101 -- Any case of Any_Type as the Etype value means that we had a
2102 -- previous error.
2111 -- The resolution of an Expression_With_Actions is determined by
2112 -- its Expression.
2120 -- If not overloaded, then we know the type, and all that needs doing
2121 -- is to check that this type is compatible with the context.
2127 -- In the overloaded case, we must select the interpretation that
2128 -- is compatible with the context (i.e. the type passed to Resolve)
2130 else
2131 -- Loop through possible interpretations
2140 -- We are only interested in interpretations that are compatible
2141 -- with the expected type, any other interpretations are ignored.
2146 Write_Eol;
2149 else
2150 -- Skip the current interpretation if it is disabled by an
2151 -- abstract operator. This action is performed only when the
2152 -- type against which we are resolving is the same as the
2153 -- type of the interpretation.
2160 then
2168 -- First matching interpretation
2176 -- Matching interpretation that is not the first, maybe an
2177 -- error, but there are some cases where preference rules are
2178 -- used to choose between the two possibilities. These and
2179 -- some more obscure cases are handled in Disambiguate.
2181 else
2182 -- If the current statement is part of a predefined library
2183 -- unit, then all interpretations which come from user level
2184 -- packages should not be considered. Check previous and
2185 -- current one.
2193 -- Previous interpretation must be discarded
2203 -- Otherwise apply further disambiguation steps
2208 -- Disambiguation has succeeded. Skip the remaining
2209 -- interpretations.
2219 else
2220 -- Before we issue an ambiguity complaint, check for the
2221 -- case of a subprogram call where at least one of the
2222 -- arguments is Any_Type, and if so suppress the message,
2223 -- since it is a cascaded error. This can also happen for
2224 -- a generalized indexing operation.
2229 then
2230 declare
2234 begin
2250 Write_Eol;
2263 then
2268 then
2272 -- Not that special case, so issue message using the flag
2273 -- Ambiguous to control printing of the header message
2274 -- only at the start of an ambiguous set.
2279 then
2280 Error_Msg_N
2283 else
2284 Error_Msg_NE -- CODEFIX
2292 Error_Msg_N
2294 else
2295 Error_Msg_N -- CODEFIX
2301 then
2302 Report_Ambiguous_Argument;
2308 -- By default, the error message refers to the candidate
2309 -- interpretation. But if it is a predefined operator, it
2310 -- is implicitly declared at the declaration of the type
2311 -- of the operand. Recover the sloc of that declaration
2312 -- for the error message.
2318 Standard_Standard
2319 then
2324 then
2332 Standard_Standard
2333 then
2338 then
2342 -- If this is an indirect call, use the subprogram_type
2343 -- in the message, to have a meaningful location. Also
2344 -- indicate if this is an inherited operation, created
2345 -- by a type declaration.
2350 then
2352 Error_Msg_Sloc :=
2354 else
2361 then
2362 -- Special-case the message for universal_fixed
2363 -- operators, which are not declared with the type
2364 -- of the operand, but appear forever in Standard.
2368 then
2369 Error_Msg_N
2372 else
2373 Error_Msg_N
2377 elsif
2379 then
2380 Error_Msg_N
2382 else
2383 Error_Msg_N -- CODEFIX
2390 -- We have a matching interpretation, Expr_Type is the type
2391 -- from this interpretation, and Seen is the entity.
2393 -- For an operator, just set the entity name. The type will be
2394 -- set by the specific operator resolution routine.
2401 N_Character_Literal,
2402 N_Delta_Aggregate,
2403 N_If_Expression)
2404 then
2407 -- AI05-0139-2: Expression is overloaded because type has
2408 -- implicit dereference. If type matches context, no implicit
2409 -- dereference is involved. If the expression is an entity,
2410 -- generate a reference to it, as this is not done for an
2411 -- overloaded construct during analysis.
2427 then
2428 -- If the node is a general indexing, the dereference is
2429 -- is inserted when resolving the rewritten form, else
2430 -- insert it now.
2434 then
2438 -- For an explicit dereference, attribute reference, range,
2439 -- short-circuit form (which is not an operator node), or call
2440 -- with a name that is an explicit dereference, there is
2441 -- nothing to be done at this point.
2444 N_And_Then,
2445 N_Explicit_Dereference,
2446 N_Identifier,
2447 N_Indexed_Component,
2448 N_Or_Else,
2449 N_Range,
2450 N_Selected_Component,
2451 N_Slice)
2453 then
2456 -- For procedure or function calls, set the type of the name,
2457 -- and also the entity pointer for the prefix.
2461 then
2468 then
2473 -- For all other cases, just set the type of the Name
2475 else
2483 -- Move to next interpretation
2491 -- At this stage Found indicates whether or not an acceptable
2492 -- interpretation exists. If not, then we have an error, except that if
2493 -- the context is Any_Type as a result of some other error, then we
2494 -- suppress the error report.
2499 -- If type we are looking for is Void, then this is the procedure
2500 -- call case, and the error is simply that what we gave is not a
2501 -- procedure name (we think of procedure calls as expressions with
2502 -- types internally, but the user doesn't think of them this way).
2506 -- Special case message if function used as a procedure
2511 then
2512 Error_Msg_NE
2515 Error_Msg_N
2519 -- Otherwise give general message (not clear what cases this
2520 -- covers, but no harm in providing for them).
2522 else
2528 -- Otherwise we do have a subexpression with the wrong type
2530 -- Check for the case of an allocator which uses an access type
2531 -- instead of the designated type. This is a common error and we
2532 -- specialize the message, posting an error on the operand of the
2533 -- allocator, complaining that we expected the designated type of
2534 -- the allocator.
2540 then
2544 -- Check for view mismatch on Null in instances, for which the
2545 -- view-swapping mechanism has no identifier.
2551 then
2556 -- Check for an aggregate. Sometimes we can get bogus aggregates
2557 -- from misuse of parentheses, and we are about to complain about
2558 -- the aggregate without even looking inside it.
2560 -- Instead, if we have an aggregate of type Any_Composite, then
2561 -- analyze and resolve the component fields, and then only issue
2562 -- another message if we get no errors doing this (otherwise
2563 -- assume that the errors in the aggregate caused the problem).
2567 then
2568 -- Disable expansion in any case. If there is a type mismatch
2569 -- it may be fatal to try to expand the aggregate. The flag
2570 -- would otherwise be set to false when the error is posted.
2574 declare
2576 -- Check one aggregate, and set Found to True if we have a
2577 -- definite error in any of its elements
2580 -- Check one element of aggregate and set Found to True if
2581 -- we definitely have an error in the element.
2583 ----------------
2584 -- Check_Aggr --
2585 ----------------
2590 begin
2603 -- If this is a default-initialized component, then
2604 -- there is nothing to check. The box will be
2605 -- replaced by the appropriate call during late
2606 -- expansion.
2610 then
2619 ----------------
2620 -- Check_Elmt --
2621 ----------------
2624 begin
2625 -- If we have a nested aggregate, go inside it (to
2626 -- attempt a naked analyze-resolve of the aggregate can
2627 -- cause undesirable cascaded errors). Do not resolve
2628 -- expression if it needs a type from context, as for
2629 -- integer * fixed expression.
2634 else
2639 then
2649 begin
2654 -- Looks like we have a type error, but check for special case
2655 -- of Address wanted, integer found, with the configuration pragma
2656 -- Allow_Integer_Address active. If we have this case, introduce
2657 -- an unchecked conversion to allow the integer expression to be
2658 -- treated as an Address. The reverse case of integer wanted,
2659 -- Address found, is treated in an analogous manner.
2666 -- Under relaxed RM semantics silently replace occurrences of null
2667 -- by System.Address_Null.
2675 -- That special Allow_Integer_Address check did not apply, so we
2676 -- have a real type error. If an error message was issued already,
2677 -- Found got reset to True, so if it's still False, issue standard
2678 -- Wrong_Type message.
2682 declare
2685 begin
2691 -- Protected operation: retrieve operation name
2695 else
2700 Error_Msg_NE
2706 declare
2710 begin
2717 Error_Msg_NE
2723 else
2727 else
2733 Resolution_Failed;
2736 -- Test if we have more than one interpretation for the context
2739 Resolution_Failed;
2742 -- Only one intepretation
2744 else
2745 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2746 -- the "+" on T is abstract, and the operands are of universal type,
2747 -- the above code will have (incorrectly) resolved the "+" to the
2748 -- universal one in Standard. Therefore check for this case and give
2749 -- an error. We can't do this earlier, because it would cause legal
2750 -- cases to get errors (when some other type has an abstract "+").
2756 then
2761 then
2762 Error_Msg_NE
2771 -- Here we have an acceptable interpretation for the context
2773 -- Propagate type information and normalize tree for various
2774 -- predefined operations. If the context only imposes a class of
2775 -- types, rather than a specific type, propagate the actual type
2776 -- downward.
2782 Typ = Any_Discrete
2783 then
2786 -- Any_Fixed is legal in a real context only if a specific fixed-
2787 -- point type is imposed. If Norman Cohen can be confused by this,
2788 -- it deserves a separate message.
2792 then
2799 -- A user-defined operator is transformed into a function call at
2800 -- this point, so that further processing knows that operators are
2801 -- really operators (i.e. are predefined operators). User-defined
2802 -- operators that are intrinsic are just renamings of the predefined
2803 -- ones, and need not be turned into calls either, but if they rename
2804 -- a different operator, we must transform the node accordingly.
2805 -- Instantiations of Unchecked_Conversion are intrinsic but are
2806 -- treated as functions, even if given an operator designator.
2811 then
2816 and then
2818 N_Subprogram_Renaming_Declaration
2819 then
2822 -- If the node is rewritten, it will be fully resolved in
2823 -- Rewrite_Renamed_Operator.
2832 when N_Aggregate =>
2833 Resolve_Aggregate (N, Ctx_Type);
2835 when N_Allocator =>
2836 Resolve_Allocator (N, Ctx_Type);
2838 when N_Short_Circuit =>
2839 Resolve_Short_Circuit (N, Ctx_Type);
2841 when N_Attribute_Reference =>
2842 Resolve_Attribute (N, Ctx_Type);
2844 when N_Case_Expression =>
2845 Resolve_Case_Expression (N, Ctx_Type);
2847 when N_Character_Literal =>
2848 Resolve_Character_Literal (N, Ctx_Type);
2850 when N_Delta_Aggregate =>
2851 Resolve_Delta_Aggregate (N, Ctx_Type);
2853 when N_Expanded_Name =>
2854 Resolve_Entity_Name (N, Ctx_Type);
2856 when N_Explicit_Dereference =>
2857 Resolve_Explicit_Dereference (N, Ctx_Type);
2859 when N_Expression_With_Actions =>
2860 Resolve_Expression_With_Actions (N, Ctx_Type);
2862 when N_Extension_Aggregate =>
2863 Resolve_Extension_Aggregate (N, Ctx_Type);
2865 when N_Function_Call =>
2866 Resolve_Call (N, Ctx_Type);
2868 when N_Identifier =>
2869 Resolve_Entity_Name (N, Ctx_Type);
2871 when N_If_Expression =>
2872 Resolve_If_Expression (N, Ctx_Type);
2874 when N_Indexed_Component =>
2875 Resolve_Indexed_Component (N, Ctx_Type);
2877 when N_Integer_Literal =>
2878 Resolve_Integer_Literal (N, Ctx_Type);
2880 when N_Membership_Test =>
2881 Resolve_Membership_Op (N, Ctx_Type);
2883 when N_Null =>
2884 Resolve_Null (N, Ctx_Type);
2886 when N_Op_And
2887 | N_Op_Or
2888 | N_Op_Xor
2889 =>
2890 Resolve_Logical_Op (N, Ctx_Type);
2892 when N_Op_Eq
2893 | N_Op_Ne
2894 =>
2895 Resolve_Equality_Op (N, Ctx_Type);
2897 when N_Op_Ge
2898 | N_Op_Gt
2899 | N_Op_Le
2900 | N_Op_Lt
2901 =>
2902 Resolve_Comparison_Op (N, Ctx_Type);
2904 when N_Op_Not =>
2905 Resolve_Op_Not (N, Ctx_Type);
2907 when N_Op_Add
2908 | N_Op_Divide
2909 | N_Op_Mod
2910 | N_Op_Multiply
2911 | N_Op_Rem
2912 | N_Op_Subtract
2913 =>
2914 Resolve_Arithmetic_Op (N, Ctx_Type);
2916 when N_Op_Concat =>
2917 Resolve_Op_Concat (N, Ctx_Type);
2919 when N_Op_Expon =>
2920 Resolve_Op_Expon (N, Ctx_Type);
2922 when N_Op_Abs
2923 | N_Op_Minus
2924 | N_Op_Plus
2925 =>
2926 Resolve_Unary_Op (N, Ctx_Type);
2928 when N_Op_Shift =>
2929 Resolve_Shift (N, Ctx_Type);
2931 when N_Procedure_Call_Statement =>
2932 Resolve_Call (N, Ctx_Type);
2934 when N_Operator_Symbol =>
2935 Resolve_Operator_Symbol (N, Ctx_Type);
2937 when N_Qualified_Expression =>
2938 Resolve_Qualified_Expression (N, Ctx_Type);
2940 -- Why is the following null, needs a comment ???
2942 when N_Quantified_Expression =>
2943 null;
2945 when N_Raise_Expression =>
2946 Resolve_Raise_Expression (N, Ctx_Type);
2948 when N_Raise_xxx_Error =>
2949 Set_Etype (N, Ctx_Type);
2951 when N_Range =>
2952 Resolve_Range (N, Ctx_Type);
2954 when N_Real_Literal =>
2955 Resolve_Real_Literal (N, Ctx_Type);
2957 when N_Reference =>
2958 Resolve_Reference (N, Ctx_Type);
2960 when N_Selected_Component =>
2961 Resolve_Selected_Component (N, Ctx_Type);
2963 when N_Slice =>
2964 Resolve_Slice (N, Ctx_Type);
2966 when N_String_Literal =>
2967 Resolve_String_Literal (N, Ctx_Type);
2969 when N_Target_Name =>
2970 Resolve_Target_Name (N, Ctx_Type);
2972 when N_Type_Conversion =>
2973 Resolve_Type_Conversion (N, Ctx_Type);
2975 when N_Unchecked_Expression =>
2976 Resolve_Unchecked_Expression (N, Ctx_Type);
2978 when N_Unchecked_Type_Conversion =>
2979 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2980 end case;
2982 -- Mark relevant use-type and use-package clauses as effective using
2983 -- the original node because constant folding may have occured and
2984 -- removed references that need to be examined.
2986 if Nkind (Original_Node (N)) in N_Op then
2987 Mark_Use_Clauses (Original_Node (N));
2988 end if;
2990 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2991 -- expression of an anonymous access type that occurs in the context
2992 -- of a named general access type, except when the expression is that
2993 -- of a membership test. This ensures proper legality checking in
2994 -- terms of allowed conversions (expressions that would be illegal to
2995 -- convert implicitly are allowed in membership tests).
2997 if Ada_Version >= Ada_2012
2998 and then Ekind (Ctx_Type) = E_General_Access_Type
2999 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3000 and then Nkind (Parent (N)) not in N_Membership_Test
3001 then
3002 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3003 Analyze_And_Resolve (N, Ctx_Type);
3004 end if;
3006 -- If the subexpression was replaced by a non-subexpression, then
3007 -- all we do is to expand it. The only legitimate case we know of
3008 -- is converting procedure call statement to entry call statements,
3009 -- but there may be others, so we are making this test general.
3011 if Nkind (N) not in N_Subexpr then
3012 Debug_A_Exit ("resolving ", N, " (done)");
3013 Expand (N);
3014 return;
3015 end if;
3017 -- The expression is definitely NOT overloaded at this point, so
3018 -- we reset the Is_Overloaded flag to avoid any confusion when
3019 -- reanalyzing the node.
3021 Set_Is_Overloaded (N, False);
3023 -- Freeze expression type, entity if it is a name, and designated
3024 -- type if it is an allocator (RM 13.14(10,11,13)).
3026 -- Now that the resolution of the type of the node is complete, and
3027 -- we did not detect an error, we can expand this node. We skip the
3028 -- expand call if we are in a default expression, see section
3029 -- "Handling of Default Expressions" in Sem spec.
3031 Debug_A_Exit ("resolving ", N, " (done)");
3033 -- We unconditionally freeze the expression, even if we are in
3034 -- default expression mode (the Freeze_Expression routine tests this
3035 -- flag and only freezes static types if it is set).
3037 -- Ada 2012 (AI05-177): The declaration of an expression function
3038 -- does not cause freezing, but we never reach here in that case.
3039 -- Here we are resolving the corresponding expanded body, so we do
3040 -- need to perform normal freezing.
3042 -- As elsewhere we do not emit freeze node within a generic. We make
3043 -- an exception for entities that are expressions, only to detect
3044 -- misuses of deferred constants and preserve the output of various
3045 -- tests.
3047 if not Inside_A_Generic or else Is_Entity_Name (N) then
3048 Freeze_Expression (N);
3049 end if;
3051 -- Now we can do the expansion
3053 Expand (N);
3054 end if;
3055 end Resolve;
3057 -------------
3058 -- Resolve --
3059 -------------
3061 -- Version with check(s) suppressed
3063 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3064 begin
3065 if Suppress = All_Checks then
3066 declare
3067 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3068 begin
3069 Scope_Suppress.Suppress := (others => True);
3070 Resolve (N, Typ);
3071 Scope_Suppress.Suppress := Sva;
3072 end;
3074 else
3075 declare
3076 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3077 begin
3078 Scope_Suppress.Suppress (Suppress) := True;
3079 Resolve (N, Typ);
3080 Scope_Suppress.Suppress (Suppress) := Svg;
3081 end;
3082 end if;
3083 end Resolve;
3085 -------------
3086 -- Resolve --
3087 -------------
3089 -- Version with implicit type
3091 procedure Resolve (N : Node_Id) is
3092 begin
3093 Resolve (N, Etype (N));
3094 end Resolve;
3096 ---------------------
3097 -- Resolve_Actuals --
3098 ---------------------
3100 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3101 Loc : constant Source_Ptr := Sloc (N);
3102 A : Node_Id;
3103 A_Id : Entity_Id;
3104 A_Typ : Entity_Id := Empty; -- init to avoid warning
3105 F : Entity_Id;
3106 F_Typ : Entity_Id;
3107 Prev : Node_Id := Empty;
3108 Orig_A : Node_Id;
3109 Real_F : Entity_Id := Empty; -- init to avoid warning
3111 Real_Subp : Entity_Id;
3112 -- If the subprogram being called is an inherited operation for
3113 -- a formal derived type in an instance, Real_Subp is the subprogram
3114 -- that will be called. It may have different formal names than the
3115 -- operation of the formal in the generic, so after actual is resolved
3116 -- the name of the actual in a named association must carry the name
3117 -- of the actual of the subprogram being called.
3119 procedure Check_Aliased_Parameter;
3120 -- Check rules on aliased parameters and related accessibility rules
3121 -- in (RM 3.10.2 (10.2-10.4)).
3123 procedure Check_Argument_Order;
3124 -- Performs a check for the case where the actuals are all simple
3125 -- identifiers that correspond to the formal names, but in the wrong
3126 -- order, which is considered suspicious and cause for a warning.
3128 procedure Check_Prefixed_Call;
3129 -- If the original node is an overloaded call in prefix notation,
3131 -- Try_Object_Operation has already verified that there is a valid
3132 -- interpretation, but the form of the actual can only be determined
3133 -- once the primitive operation is identified.
3136 -- Emit an error concerning the illegal usage of an effectively volatile
3137 -- object in interfering context (SPARK RM 7.13(12)).
3140 -- If the actual is missing in a call, insert in the actuals list
3141 -- an instance of the default expression. The insertion is always
3142 -- a named association.
3145 -- Check whether T1 and T2, or their full views, are derived from a
3146 -- common type. Used to enforce the restrictions on array conversions
3147 -- of AI95-00246.
3150 -- Predicate to determine whether an actual that is a concatenation
3151 -- will be evaluated statically and does not need a transient scope.
3152 -- This must be determined before the actual is resolved and expanded
3153 -- because if needed the transient scope must be introduced earlier.
3155 -----------------------------
3156 -- Check_Aliased_Parameter --
3157 -----------------------------
3162 begin
3170 else
3177 -- In a generic body assume the worst for generic formals:
3178 -- they can have a constrained partial view (AI05-041).
3184 then
3187 else
3192 else
3204 then
3212 then
3213 Error_Msg_N
3219 --------------------------
3220 -- Check_Argument_Order --
3221 --------------------------
3224 begin
3225 -- Nothing to do if no parameters, or original node is neither a
3226 -- function call nor a procedure call statement (happens in the
3227 -- operator-transformed-to-function call case), or the call does
3228 -- not come from source, or this warning is off.
3230 if not Warn_On_Parameter_Order
3234 then
3238 declare
3241 begin
3242 -- Nothing to do if only one parameter
3248 -- Here if at least two arguments
3250 declare
3256 -- Set True if an out of order case is found
3258 begin
3259 -- Collect identifier names of actuals, fail if any actual is
3260 -- not a simple identifier, and record max length of name.
3266 else
3272 -- If we got this far, all actuals are identifiers and the list
3273 -- of their names is stored in the Actuals array.
3278 -- If we ran out of formals, that's odd, probably an error
3279 -- which will be detected elsewhere, but abandon the search.
3285 -- If name matches and is in order OK
3290 else
3291 -- If no match, see if it is elsewhere in list and if so
3292 -- flag potential wrong order if type is compatible.
3296 and then
3298 then
3304 -- No match
3312 -- If Formals left over, also probably an error, skip warning
3318 -- Here we give the warning if something was out of order
3321 Error_Msg_N
3328 -------------------------
3329 -- Check_Prefixed_Call --
3330 -------------------------
3339 begin
3340 -- Check whether the call is a prefixed call, with or without
3341 -- additional actuals.
3344 or else
3350 then
3353 then
3354 -- Introduce dereference on object in prefix
3356 New_A :=
3364 then
3365 -- Introduce an implicit 'Access in prefix
3368 Error_Msg_NE
3384 ---------------------------------------
3385 -- Flag_Effectively_Volatile_Objects --
3386 ---------------------------------------
3390 -- Determine whether arbitrary node N denotes an effectively volatile
3391 -- object and if it does, emit an error.
3393 -----------------
3394 -- Flag_Object --
3395 -----------------
3400 begin
3401 -- Do not consider nested function calls because they have already
3402 -- been processed during their own resolution.
3414 then
3415 Error_Msg_N
3427 -- Start of processing for Flag_Effectively_Volatile_Objects
3429 begin
3433 --------------------
3434 -- Insert_Default --
3435 --------------------
3441 begin
3442 -- Missing argument in call, nothing to insert
3447 else
3448 -- Note that we do a full New_Copy_Tree, so that any associated
3449 -- Itypes are properly copied. This may not be needed any more,
3450 -- but it does no harm as a safety measure. Defaults of a generic
3451 -- formal may be out of bounds of the corresponding actual (see
3452 -- cc1311b) and an additional check may be required.
3454 Actval :=
3455 New_Copy_Tree
3460 -- Propagate dimension information, if any.
3466 then
3472 then
3475 then
3476 -- If default is a real literal, do not introduce a
3477 -- conversion whose effect may depend on the run-time
3478 -- size of universal real.
3482 else
3493 -- Resolve aggregates with their base type, to avoid scope
3494 -- anomalies: the subtype was first built in the subprogram
3495 -- declaration, and the current call may be nested.
3499 else
3503 else
3506 -- See note above concerning aggregates
3510 then
3513 -- Resolve entities with their own type, which may differ from
3514 -- the type of a reference in a generic context (the view
3515 -- swapping mechanism did not anticipate the re-analysis of
3516 -- default values in calls).
3521 else
3526 -- If default is a tag indeterminate function call, propagate tag
3527 -- to obtain proper dispatching.
3531 then
3536 -- If the default expression raises constraint error, then just
3537 -- silently replace it with an N_Raise_Constraint_Error node, since
3538 -- we already gave the warning on the subprogram spec. If node is
3539 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3540 -- the warnings removal machinery.
3544 then
3553 Assoc :=
3558 -- Case of insertion is first named actual
3562 then
3569 else
3573 else
3577 -- Case of insertion is not first named actual
3579 else
3580 Set_Next_Named_Actual
3592 -------------------
3593 -- Same_Ancestor --
3594 -------------------
3600 begin
3603 then
3609 then
3616 --------------------------
3617 -- Static_Concatenation --
3618 --------------------------
3621 begin
3628 -- Concatenation is static when both operands are static and
3629 -- the concatenation operator is a predefined one.
3632 and then
3634 and then
3639 declare
3641 begin
3644 and then
3648 else
3654 -- Start of processing for Resolve_Actuals
3656 begin
3657 Check_Argument_Order;
3661 and then In_Instance
3664 then
3666 else
3671 Check_Prefixed_Call;
3685 -- If we have an error in any actual or formal, indicated by a type
3686 -- of Any_Type, then abandon resolution attempt, and set result type
3687 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3688 -- type is imposed from context.
3692 then
3699 -- Case where actual is present
3701 -- If the actual is an entity, generate a reference to it now. We
3702 -- do this before the actual is resolved, because a formal of some
3703 -- protected subprogram, or a task discriminant, will be rewritten
3704 -- during expansion, and the source entity reference may be lost.
3709 then
3710 -- Annotate the tree by creating a variable reference marker when
3711 -- the actual denotes a variable reference, in case the reference
3712 -- is folded or optimized away. The variable reference marker is
3713 -- automatically saved for later examination by the ABE Processing
3714 -- phase. The status of the reference is set as follows:
3716 -- status mode
3717 -- read IN, IN OUT
3718 -- write IN OUT, OUT
3720 if Needs_Variable_Reference_Marker
3723 then
3724 Build_Variable_Reference_Marker
3735 then
3742 -- RM 6.4.1(12): For an out parameter that is passed by
3743 -- copy, the formal parameter object is created, and:
3745 -- * For an access type, the formal parameter is initialized
3746 -- from the value of the actual, without checking that the
3747 -- value satisfies any constraint, any predicate, or any
3748 -- exclusion of the null value.
3750 -- * For a scalar type that has the Default_Value aspect
3751 -- specified, the formal parameter is initialized from the
3752 -- value of the actual, without checking that the value
3753 -- satisfies any constraint or any predicate.
3754 -- I do not understand why this case is included??? this is
3755 -- not a case where an OUT parameter is treated as IN OUT.
3757 -- * For a composite type with discriminants or that has
3758 -- implicit initial values for any subcomponents, the
3759 -- behavior is as for an in out parameter passed by copy.
3761 -- Hence for these cases we generate the read reference now
3762 -- (the write reference will be generated later by
3763 -- Note_Possible_Modification).
3766 and then
3768 or else
3770 and then
3772 or else
3775 or else Is_Partially_Initialized_Type
3777 then
3787 then
3788 -- If style checking mode on, check match of formal name
3796 -- If the formal is Out or In_Out, do not resolve and expand the
3797 -- conversion, because it is subsequently expanded into explicit
3798 -- temporaries and assignments. However, the object of the
3799 -- conversion can be resolved. An exception is the case of tagged
3800 -- type conversion with a class-wide actual. In that case we want
3801 -- the tag check to occur and no temporary will be needed (no
3802 -- representation change can occur) and the parameter is passed by
3803 -- reference, so we go ahead and resolve the type conversion.
3804 -- Another exception is the case of reference to component or
3805 -- subcomponent of a bit-packed array, in which case we want to
3806 -- defer expansion to the point the in and out assignments are
3807 -- performed.
3812 then
3815 then
3816 -- In a view conversion, the conversion must be legal in
3817 -- both directions, and thus both component types must be
3818 -- aliased, or neither (4.6 (8)).
3820 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3821 -- the privacy requirement should not apply to generic
3822 -- types, and should be checked in an instance. ARG query
3823 -- is in order ???
3827 then
3828 Error_Msg_N
3832 -- Comment here??? what set of cases???
3834 elsif
3836 then
3837 -- Check view conv between unrelated by ref array types
3841 then
3842 Error_Msg_N
3846 -- In Ada 2005 mode, check view conversion component
3847 -- type cannot be private, tagged, or volatile. Note
3848 -- that we only apply this to source conversions. The
3849 -- generated code can contain conversions which are
3850 -- not subject to this test, and we cannot extract the
3851 -- component type in such cases since it is not present.
3855 then
3856 declare
3858 Component_Type
3860 begin
3865 then
3866 Error_Msg_N
3877 -- Resolve expression if conversion is all OK
3882 then
3886 -- If the actual is a function call that returns a limited
3887 -- unconstrained object that needs finalization, create a
3888 -- transient scope for it, so that it can receive the proper
3889 -- finalization list.
3891 elsif Expander_Active
3897 then
3901 -- A small optimization: if one of the actuals is a concatenation
3902 -- create a block around a procedure call to recover stack space.
3903 -- This alleviates stack usage when several procedure calls in
3904 -- the same statement list use concatenation. We do not perform
3905 -- this wrapping for code statements, where the argument is a
3906 -- static string, and we want to preserve warnings involving
3907 -- sequences of such statements.
3909 elsif Expander_Active
3915 then
3919 else
3923 and then
3926 then
3927 Error_Msg_N
3940 -- (Ada 2005: AI-251): If the actual is an allocator whose
3941 -- directly designated type is a class-wide interface, we build
3942 -- an anonymous access type to use it as the type of the
3943 -- allocator. Later, when the subprogram call is expanded, if
3944 -- the interface has a secondary dispatch table the expander
3945 -- will add a type conversion to force the correct displacement
3946 -- of the pointer.
3949 declare
3955 begin
3958 then
3961 Set_Directly_Designated_Type
3966 -- Ada 2005, AI-162:If the actual is an allocator, the
3967 -- innermost enclosing statement is the master of the
3968 -- created object. This needs to be done with expansion
3969 -- enabled only, otherwise the transient scope will not
3970 -- be removed in the expansion of the wrapped construct.
3972 if Expander_Active
3975 then
3976 Establish_Transient_Scope
3986 -- (Ada 2005): The call may be to a primitive operation of a
3987 -- tagged synchronized type, declared outside of the type. In
3988 -- this case the controlling actual must be converted to its
3989 -- corresponding record type, which is the formal type. The
3990 -- actual may be a subtype, either because of a constraint or
3991 -- because it is a generic actual, so use base type to locate
3992 -- concurrent type.
3999 then
4000 -- If the actual is overloaded, look for an interpretation
4001 -- that has a synchronized type.
4006 else
4007 declare
4011 begin
4016 then
4026 declare
4029 begin
4032 else
4036 -- Tagged synchronized type (case 1): the actual is a
4037 -- concurrent type.
4041 then
4043 Unchecked_Convert_To
4047 -- Tagged synchronized type (case 2): the formal is a
4048 -- concurrent type.
4051 and then Present
4056 then
4059 -- Common case
4061 else
4066 -- Not a synchronized operation
4068 else
4076 -- An actual cannot be an untagged formal incomplete type
4081 then
4082 Error_Msg_N
4088 N_Procedure_Call_Statement)
4089 then
4090 -- In formal mode, check that actual parameters matching
4091 -- formals of tagged types are objects (or ancestor type
4092 -- conversions of objects), not general expressions.
4099 declare
4104 begin
4106 Check_SPARK_05_Restriction
4109 -- In formal mode, the only view conversions are those
4110 -- involving ancestor conversion of an extended type.
4112 elsif not
4118 then
4119 if Ekind_In
4121 then
4122 Check_SPARK_05_Restriction
4125 else
4126 Check_SPARK_05_Restriction
4130 else
4135 else
4139 -- In formal mode, the only view conversions are those
4140 -- involving ancestor conversion of an extended type.
4144 then
4145 Check_SPARK_05_Restriction
4151 -- has warnings suppressed, then we reset Never_Set_In_Source for
4152 -- the calling entity. The reason for this is to catch cases like
4153 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4154 -- uses trickery to modify an IN parameter.
4161 then
4165 -- Perform error checks for IN and IN OUT parameters
4169 -- Check unset reference. For scalar parameters, it is clearly
4170 -- wrong to pass an uninitialized value as either an IN or
4171 -- IN-OUT parameter. For composites, it is also clearly an
4172 -- error to pass a completely uninitialized value as an IN
4173 -- parameter, but the case of IN OUT is trickier. We prefer
4174 -- not to give a warning here. For example, suppose there is
4175 -- a routine that sets some component of a record to False.
4176 -- It is perfectly reasonable to make this IN-OUT and allow
4177 -- either initialized or uninitialized records to be passed
4178 -- in this case.
4180 -- For partially initialized composite values, we also avoid
4181 -- warnings, since it is quite likely that we are passing a
4182 -- partially initialized value and only the initialized fields
4183 -- will in fact be read in the subprogram.
4188 then
4192 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4193 -- actual to a nested call, since this constitutes a reading of
4194 -- the parameter, which is not allowed.
4199 then
4204 -- In -gnatd.q mode, forget that a given array is constant when
4205 -- it is passed as an IN parameter to a foreign-convention
4206 -- subprogram. This is in case the subprogram evilly modifies the
4207 -- object. Of course, correct code would use IN OUT.
4209 if Debug_Flag_Dot_Q
4215 then
4219 -- Case of OUT or IN OUT parameter
4223 -- For an Out parameter, check for useless assignment. Note
4224 -- that we can't set Last_Assignment this early, because we may
4225 -- kill current values in Resolve_Call, and that call would
4226 -- clobber the Last_Assignment field.
4228 -- Note: call Warn_On_Useless_Assignment before doing the check
4229 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4230 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4231 -- reflects the last assignment, not this one.
4238 then
4243 -- Validate the form of the actual. Note that the call to
4244 -- Is_OK_Variable_For_Out_Formal generates the required
4245 -- reference in this case.
4247 -- A call to an initialization procedure for an aggregate
4248 -- component may initialize a nested component of a constant
4249 -- designated object. In this context the object is variable.
4253 then
4259 then
4260 Error_Msg_N
4265 Error_Msg_N
4272 -- What's the following about???
4276 else
4277 Kill_All_Checks;
4286 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4290 -- Apply predicate tests except in certain special cases. Note
4291 -- that it might be more consistent to apply these only when
4292 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4293 -- for the outbound predicate tests ??? In any case indicate
4294 -- the function being called, for better warnings if the call
4295 -- leads to an infinite recursion.
4301 -- Apply required constraint checks
4303 -- Gigi looks at the check flag and uses the appropriate types.
4304 -- For now since one flag is used there is an optimization
4305 -- which might not be done in the IN OUT case since Gigi does
4306 -- not do any analysis. More thought required about this ???
4308 -- In fact is this comment obsolete??? doesn't the expander now
4309 -- generate all these tests anyway???
4322 then
4325 -- For view conversions of a discriminated object, apply
4326 -- check to object itself, the conversion alreay has the
4327 -- proper type.
4331 then
4338 then
4344 then
4347 else
4351 -- Ada 2005 (AI-231): Note that the controlling parameter case
4352 -- already existed in Ada 95, which is partially checked
4353 -- elsewhere (see Checks), and we don't want the warning
4354 -- message to differ.
4359 then
4361 Apply_Compile_Time_Constraint_Error
4367 Apply_Compile_Time_Constraint_Error
4376 -- Checks for OUT parameters and IN OUT parameters
4380 -- If there is a type conversion, make sure the return value
4381 -- meets the constraints of the variable before the conversion.
4385 Apply_Scalar_Range_Check
4388 -- In addition, the returned value of the parameter must
4389 -- satisfy the bounds of the object type (see comment
4390 -- below).
4394 else
4395 Apply_Range_Check
4399 -- If no conversion, apply scalar range checks and length check
4400 -- based on the subtype of the actual (NOT that of the formal).
4401 -- This indicates that the check takes place on return from the
4402 -- call. During expansion the required constraint checks are
4403 -- inserted. In GNATprove mode, in the absence of expansion,
4404 -- the flag indicates that the returned value is valid.
4406 else
4412 then
4414 else
4419 -- Note: we do not apply the predicate checks for the case of
4420 -- OUT and IN OUT parameters. They are instead applied in the
4421 -- Expand_Actuals routine in Exp_Ch6.
4424 -- An actual associated with an access parameter is implicitly
4425 -- converted to the anonymous access type of the formal and must
4426 -- satisfy the legality checks for access conversions.
4430 Error_Msg_N
4434 -- If the actual is an access selected component of a variable,
4435 -- the call may modify its designated object. It is reasonable
4436 -- to treat this as a potential modification of the enclosing
4437 -- record, to prevent spurious warnings that it should be
4438 -- declared as a constant, because intuitively programmers
4439 -- regard the designated subcomponent as part of the record.
4444 then
4449 -- Check bad case of atomic/volatile argument (RM C.6(12))
4453 then
4456 then
4457 Error_Msg_NE
4463 then
4464 Error_Msg_NE
4470 -- Check that subprograms don't have improper controlling
4471 -- arguments (RM 3.9.2 (9)).
4473 -- A primitive operation may have an access parameter of an
4474 -- incomplete tagged type, but a dispatching call is illegal
4475 -- if the type is still incomplete.
4481 declare
4483 begin
4487 then
4488 Error_Msg_NE
4499 -- Apply legality rule 3.9.2 (9/1)
4504 and then not In_Instance
4505 then
4510 Error_Msg_NE
4514 -- Apply the checks described in 3.10.2(27): if the context is a
4515 -- specific access-to-object, the actual cannot be class-wide.
4516 -- Use base type to exclude access_to_subprogram cases.
4523 and then
4528 -- Disable these checks for call to imported C++ subprograms
4530 and then not
4534 then
4535 Error_Msg_N
4540 Error_Msg_NE
4545 Check_Aliased_Parameter;
4549 -- If it is a named association, treat the selector_name as a
4550 -- proper identifier, and mark the corresponding entity.
4554 -- Ignore reference in SPARK mode, as it refers to an entity not
4555 -- in scope at the point of reference, so the reference should
4556 -- be ignored for computing effects of subprograms.
4558 and then not GNATprove_Mode
4559 then
4560 -- If subprogram is overridden, use name of formal that
4561 -- is being called.
4567 else
4581 -- The following checks are only relevant when SPARK_Mode is on as
4582 -- they are not standard Ada legality rule. Internally generated
4583 -- temporaries are ignored.
4587 -- An effectively volatile object may act as an actual when the
4588 -- corresponding formal is of a non-scalar effectively volatile
4589 -- type (SPARK RM 7.1.3(11)).
4593 then
4596 -- An effectively volatile object may act as an actual in a
4597 -- call to an instance of Unchecked_Conversion.
4598 -- (SPARK RM 7.1.3(11)).
4603 -- The actual denotes an object
4606 Error_Msg_N
4610 -- Otherwise the actual denotes an expression. Inspect the
4611 -- expression and flag each effectively volatile object with
4612 -- enabled property Async_Writers or Effective_Reads as illegal
4613 -- because it apprears within an interfering context. Note that
4614 -- this is usually done in Resolve_Entity_Name, but when the
4615 -- effectively volatile object appears as an actual in a call,
4616 -- the call must be resolved first.
4618 else
4622 -- An effectively volatile variable cannot act as an actual
4623 -- parameter in a procedure call when the variable has enabled
4624 -- property Effective_Reads and the corresponding formal is of
4625 -- mode IN (SPARK RM 7.1.3(10)).
4630 then
4636 then
4637 Error_Msg_NE
4648 -- A formal parameter of a specific tagged type whose related
4649 -- subprogram is subject to pragma Extensions_Visible with value
4650 -- "False" cannot act as an actual in a subprogram with value
4651 -- "True" (SPARK RM 6.1.7(3)).
4655 Extensions_Visible_True
4656 then
4657 Error_Msg_N
4660 Error_Msg_NE
4664 -- The actual parameter of a Ghost subprogram whose formal is of
4665 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4673 then
4674 Error_Msg_NE
4680 else
4687 -- Case where actual is not present
4689 else
4690 Insert_Default;
4701 -----------------------
4702 -- Resolve_Allocator --
4703 -----------------------
4715 procedure Check_Allocator_Discrim_Accessibility
4718 -- Check that accessibility level associated with an access discriminant
4719 -- initialized in an allocator by the expression Disc_Exp is not deeper
4720 -- than the level of the allocator type Alloc_Typ. An error message is
4721 -- issued if this condition is violated. Specialized checks are done for
4722 -- the cases of a constraint expression which is an access attribute or
4723 -- an access discriminant.
4726 -- If the allocator is an actual in a call, it is allowed to be class-
4727 -- wide when the context is not because it is a controlling actual.
4729 -------------------------------------------
4730 -- Check_Allocator_Discrim_Accessibility --
4731 -------------------------------------------
4733 procedure Check_Allocator_Discrim_Accessibility
4736 is
4737 begin
4740 then
4741 Error_Msg_N
4744 -- When the expression is an Access attribute the level of the prefix
4745 -- object must not be deeper than that of the allocator's type.
4749 Attribute_Access
4752 then
4753 Error_Msg_N
4755 Disc_Exp);
4757 -- When the expression is an access discriminant the check is against
4758 -- the level of the prefix object.
4764 then
4765 Error_Msg_N
4767 Disc_Exp);
4769 -- All other cases are legal
4771 else
4776 ----------------------------
4777 -- In_Dispatching_Context --
4778 ----------------------------
4783 begin
4789 -- Start of processing for Resolve_Allocator
4791 begin
4792 -- Replace general access with specific type
4802 -- For qualified expression, resolve the expression using the given
4803 -- subtype (nothing to do for type mark, subtype indication)
4808 and then not In_Dispatching_Context
4809 then
4810 Error_Msg_N
4818 -- Allocators generated by the build-in-place expansion mechanism
4819 -- are explicitly marked as coming from source but do not need to be
4820 -- checked for limited initialization. To exclude this case, ensure
4821 -- that the parent of the allocator is a source node.
4822 -- The return statement constructed for an Expression_Function does
4823 -- not come from source but requires a limited check.
4827 and then
4829 or else
4833 and then not In_Instance_Body
4834 then
4837 Error_Msg_N
4840 else
4841 Error_Msg_N
4849 -- A qualified expression requires an exact match of the type. Class-
4850 -- wide matching is not allowed.
4855 then
4859 -- Calls to build-in-place functions are not currently supported in
4860 -- allocators for access types associated with a simple storage pool.
4861 -- Supporting such allocators may require passing additional implicit
4862 -- parameters to build-in-place functions (or a significant revision
4863 -- of the current b-i-p implementation to unify the handling for
4864 -- multiple kinds of storage pools). ???
4868 then
4869 declare
4872 begin
4874 and then
4875 Present (Get_Rep_Pragma
4877 then
4878 Error_Msg_N
4885 -- A special accessibility check is needed for allocators that
4886 -- constrain access discriminants. The level of the type of the
4887 -- expression used to constrain an access discriminant cannot be
4888 -- deeper than the type of the allocator (in contrast to access
4889 -- parameters, where the level of the actual can be arbitrary).
4891 -- We can't use Valid_Conversion to perform this check because in
4892 -- general the type of the allocator is unrelated to the type of
4893 -- the access discriminant.
4897 then
4904 then
4907 -- Get the first component expression of the aggregate
4917 else
4921 else
4940 else
4945 else
4954 -- For a subtype mark or subtype indication, freeze the subtype
4956 else
4960 Error_Msg_N
4964 -- A special accessibility check is needed for allocators that
4965 -- constrain access discriminants. The level of the type of the
4966 -- expression used to constrain an access discriminant cannot be
4967 -- deeper than the type of the allocator (in contrast to access
4968 -- parameters, where the level of the actual can be arbitrary).
4969 -- We can't use Valid_Conversion to perform this check because
4970 -- in general the type of the allocator is unrelated to the type
4971 -- of the access discriminant.
4976 then
4986 else
5000 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5001 -- check that the level of the type of the created object is not deeper
5002 -- than the level of the allocator's access type, since extensions can
5003 -- now occur at deeper levels than their ancestor types. This is a
5004 -- static accessibility level check; a run-time check is also needed in
5005 -- the case of an initialized allocator with a class-wide argument (see
5006 -- Expand_Allocator_Expression).
5010 then
5011 declare
5014 begin
5019 else
5025 then
5028 Error_Msg_N
5038 -- Do not apply Ada 2005 accessibility checks on a class-wide
5039 -- allocator if the type given in the allocator is a formal
5040 -- type. A run-time check will be performed in the instance.
5043 Error_Msg_N
5051 -- Check for allocation from an empty storage pool. But do not complain
5052 -- if it's a return statement for a build-in-place function, because the
5053 -- allocator is there just in case the caller uses an allocator. If the
5054 -- caller does use an allocator, it will be caught at the call site.
5058 then
5061 -- If the context is an unchecked conversion, as may happen within an
5062 -- inlined subprogram, the allocator is being resolved with its own
5063 -- anonymous type. In that case, if the target type has a specific
5064 -- storage pool, it must be inherited explicitly by the allocator type.
5068 then
5069 Set_Associated_Storage_Pool
5077 -- Check that an allocator with task parts isn't for a nested access
5078 -- type when restriction No_Task_Hierarchy applies.
5082 then
5086 -- An illegal allocator may be rewritten as a raise Program_Error
5087 -- statement.
5091 -- Avoid coextension processing for an allocator that is the
5092 -- expansion of a build-in-place function call.
5096 N_Qualified_Expression
5098 N_Function_Call
5099 and then Is_Expanded_Build_In_Place_Call
5101 then
5104 else
5105 -- An anonymous access discriminant is the definition of a
5106 -- coextension.
5110 N_Discriminant_Specification
5111 then
5112 declare
5116 begin
5119 -- Ada 2012 AI05-0052: If the designated type of the
5120 -- allocator is limited, then the allocator shall not
5121 -- be used to define the value of an access discriminant
5122 -- unless the discriminated type is immutably limited.
5127 then
5128 Error_Msg_N
5131 N);
5135 -- Avoid marking an allocator as a dynamic coextension if it is
5136 -- within a static construct.
5141 -- Finalization and deallocation of coextensions utilizes an
5142 -- approximate implementation which does not directly adhere
5143 -- to the semantic rules. Warn on potential issues involving
5144 -- coextensions.
5147 Error_Msg_N
5150 else
5151 Error_Msg_N
5157 -- Cleanup for potential static coextensions
5159 else
5163 -- Anonymous access-to-controlled objects are not finalized on
5164 -- time because this involves run-time ownership and currently
5165 -- this property is not available. In rare cases the object may
5166 -- not be finalized at all. Warn on potential issues involving
5167 -- anonymous access-to-controlled objects.
5171 then
5172 Error_Msg_N
5182 -- Report a simple error: if the designated object is a local task,
5183 -- its body has not been seen yet, and its activation will fail an
5184 -- elaboration check.
5191 then
5197 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5198 -- type with a task component on a subpool. This action must raise
5199 -- Program_Error at runtime.
5205 then
5217 ---------------------------
5218 -- Resolve_Arithmetic_Op --
5219 ---------------------------
5221 -- Used for resolving all arithmetic operators except exponentiation
5232 -- We do the resolution using the base type, because intermediate values
5233 -- in expressions always are of the base type, not a subtype of it.
5236 -- Returns True if N is in a context that expects "any real type"
5239 -- Return True iff given type is Integer or universal real/integer
5242 -- Choose type of integer literal in fixed-point operation to conform
5243 -- to available fixed-point type. T is the type of the other operand,
5244 -- which is needed to determine the expected type of N.
5247 -- Set operand type to T if universal
5249 -------------------------------
5250 -- Expected_Type_Is_Any_Real --
5251 -------------------------------
5254 begin
5255 -- N is the expression after "delta" in a fixed_point_definition;
5256 -- see RM-3.5.9(6):
5259 N_Decimal_Fixed_Point_Definition,
5261 -- N is one of the bounds in a real_range_specification;
5262 -- see RM-3.5.7(5):
5264 N_Real_Range_Specification,
5266 -- N is the expression of a delta_constraint;
5267 -- see RM-J.3(3):
5269 N_Delta_Constraint);
5272 -----------------------------
5273 -- Is_Integer_Or_Universal --
5274 -----------------------------
5281 begin
5287 else
5293 then
5304 ----------------------------
5305 -- Set_Mixed_Mode_Operand --
5306 ----------------------------
5312 begin
5315 -- A universal integer literal is resolved as standard integer
5316 -- except in the case of a fixed-point result, where we leave it
5317 -- as universal (to be handled by Exp_Fixd later on)
5321 else
5329 then
5330 -- A universal real can appear in a fixed-type context. We resolve
5331 -- the literal with that context, even though this might raise an
5332 -- exception prematurely (the other operand may be zero).
5339 then
5340 -- Integer arg in mixed-mode operation. Resolve with universal
5341 -- type, in case preference rule must be applied.
5347 -- If the operand is part of a fixed multiplication operation,
5348 -- a conversion will be applied to each operand, so resolve it
5349 -- with its own type.
5354 else
5355 -- Not a mixed-mode operation, resolve with context
5362 -- N may itself be a mixed-mode operation, so use context type
5369 then
5370 -- Must be (fixed * fixed) operation, operand must have one
5371 -- compatible interpretation.
5378 then
5379 -- C * F(X) in a fixed context, where C is a real literal or a
5380 -- fixed-point expression. F must have either a fixed type
5381 -- interpretation or an integer interpretation, but not both.
5388 else
5395 else
5403 -- Reanalyze the literal with the fixed type of the context. If
5404 -- context is Universal_Fixed, we are within a conversion, leave
5405 -- the literal as a universal real because there is no usable
5406 -- fixed type, and the target of the conversion plays no role in
5407 -- the resolution.
5409 declare
5413 begin
5416 else
5422 then
5424 else
5432 -- A universal real conditional expression can appear in a fixed-type
5433 -- context and must be resolved with that context to facilitate the
5434 -- code generation in the back end.
5439 then
5442 else
5447 ----------------------
5448 -- Set_Operand_Type --
5449 ----------------------
5452 begin
5455 then
5460 -- Start of processing for Resolve_Arithmetic_Op
5462 begin
5467 then
5471 -- Special-case for mixed-mode universal expressions or fixed point type
5472 -- operation: each argument is resolved separately. The same treatment
5473 -- is required if one of the operands of a fixed point operation is
5474 -- universal real, since in this case we don't do a conversion to a
5475 -- specific fixed-point type (instead the expander handles the case).
5477 -- Set the type of the node to its universal interpretation because
5478 -- legality checks on an exponentiation operand need the context.
5483 then
5494 or else
5497 then
5502 -- If context is a fixed type and one operand is integer, the other
5503 -- is resolved with the type of the context.
5508 then
5515 then
5519 -- If both operands are universal and the context is a floating
5520 -- point type, the operands are resolved to the type of the context.
5526 else
5531 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5532 -- multiplying operators from being used when the expected type is
5533 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5534 -- some cases where the expected type is actually Any_Real;
5535 -- Expected_Type_Is_Any_Real takes care of that case.
5539 then
5543 N_Unchecked_Type_Conversion)
5544 then
5551 else
5554 and then not
5556 N_Unchecked_Type_Conversion)
5557 then
5558 Error_Msg_N
5563 -- The expected type is "any real type" in contexts like
5565 -- type T is delta <universal_fixed-expression> ...
5567 -- in which case we need to set the type to Universal_Real
5568 -- so that static expression evaluation will work properly.
5572 else
5582 then
5587 -- If no previous errors, this is only possible if one operand is
5588 -- overloaded and the context is universal. Resolve as such.
5593 else
5595 and then
5597 then
5601 -- If the context is Universal_Fixed and the operands are also
5602 -- universal fixed, this is an error, unless there is only one
5603 -- applicable fixed_point type (usually Duration).
5611 else
5616 else
5621 -- If one of the arguments was resolved to a non-universal type.
5622 -- label the result of the operation itself with the same type.
5623 -- Do the same for the universal argument, if any.
5635 -- In SPARK, a multiplication or division with operands of fixed point
5636 -- types must be qualified or explicitly converted to identify the
5637 -- result type.
5642 and then
5644 then
5645 Check_SPARK_05_Restriction
5649 -- Set overflow and division checking bit
5656 -- Give warning if explicit division by zero
5660 then
5666 or else
5669 then
5670 -- Specialize the warning message according to the operation.
5671 -- When SPARK_Mode is On, force a warning instead of an error
5672 -- in that case, as this likely corresponds to deactivated
5673 -- code. The following warnings are for the case
5678 -- For division, we have two cases, for float division
5679 -- of an unconstrained float type, on a machine where
5680 -- Machine_Overflows is false, we don't get an exception
5681 -- at run-time, but rather an infinity or Nan. The Nan
5682 -- case is pretty obscure, so just warn about infinities.
5686 and then not Machine_Overflows_On_Target
5687 then
5688 Error_Msg_N
5692 -- For all other cases, we get a Constraint_Error
5694 else
5695 Apply_Compile_Time_Constraint_Error
5702 Apply_Compile_Time_Constraint_Error
5708 Apply_Compile_Time_Constraint_Error
5713 -- Division by zero can only happen with division, rem,
5714 -- and mod operations.
5720 -- In GNATprove mode, we enable the division check so that
5721 -- GNATprove will issue a message if it cannot be proved.
5727 -- Otherwise just set the flag to check at run time
5729 else
5734 -- If Restriction No_Implicit_Conditionals is active, then it is
5735 -- violated if either operand can be negative for mod, or for rem
5736 -- if both operands can be negative.
5740 then
5741 declare
5748 -- Set if corresponding operand might be negative
5750 begin
5751 Determine_Range
5755 Determine_Range
5759 -- Check if we will be generating conditionals. There are two
5760 -- cases where that can happen, first for REM, the only case
5761 -- is largest negative integer mod -1, where the division can
5762 -- overflow, but we still have to give the right result. The
5763 -- front end generates a test for this annoying case. Here we
5764 -- just test if both operands can be negative (that's what the
5765 -- expander does, so we match its logic here).
5767 -- The second case is mod where either operand can be negative.
5768 -- In this case, the back end has to generate additional tests.
5771 or else
5773 then
5784 ------------------
5785 -- Resolve_Call --
5786 ------------------
5789 function Same_Or_Aliased_Subprograms
5792 -- Returns True if the subprogram entity S is the same as E or else
5793 -- S is an alias of E.
5795 ---------------------------------
5796 -- Same_Or_Aliased_Subprograms --
5797 ---------------------------------
5799 function Same_Or_Aliased_Subprograms
5802 is
5804 begin
5808 -- Local variables
5822 -- Start of processing for Resolve_Call
5824 begin
5825 -- Preserve relevant elaboration-related attributes of the context which
5826 -- are no longer available or very expensive to recompute once analysis,
5827 -- resolution, and expansion are over.
5829 Mark_Elaboration_Attributes
5835 -- The context imposes a unique interpretation with type Typ on a
5836 -- procedure or function call. Find the entity of the subprogram that
5837 -- yields the expected type, and propagate the corresponding formal
5838 -- constraints on the actuals. The caller has established that an
5839 -- interpretation exists, and emitted an error if not unique.
5841 -- First deal with the case of a call to an access-to-subprogram,
5842 -- dereference made explicit in Analyze_Call.
5848 else
5849 -- Find the interpretation whose type (a subprogram type) has a
5850 -- return type that is compatible with the context. Analysis of
5851 -- the node has established that one exists.
5870 -- If the prefix is not an entity, then resolve it
5876 -- For an indirect call, we always invalidate checks, since we do not
5877 -- know whether the subprogram is local or global. Yes we could do
5878 -- better here, e.g. by knowing that there are no local subprograms,
5879 -- but it does not seem worth the effort. Similarly, we kill all
5880 -- knowledge of current constant values.
5882 Kill_Current_Values;
5884 -- If this is a procedure call which is really an entry call, do
5885 -- the conversion of the procedure call to an entry call. Protected
5886 -- operations use the same circuitry because the name in the call
5887 -- can be an arbitrary expression with special resolution rules.
5892 then
5899 -- Annotate the tree by creating a call marker in case the original
5900 -- call is transformed by expansion. The call marker is automatically
5901 -- saved for later examination by the ABE Processing phase.
5905 -- Kill checks and constant values, as above for indirect case
5906 -- Who knows what happens when another task is activated?
5908 Kill_Current_Values;
5911 -- Normal subprogram call with name established in Resolve
5917 -- Otherwise we must have the case of an overloaded call
5919 else
5922 -- Initialize Nam to prevent warning (we know it will be assigned
5923 -- in the loop below, but the compiler does not know that).
5943 then
5944 -- The prefix is a parameterless function call that returns an access
5945 -- to subprogram. If parameters are present in the current call, add
5946 -- add an explicit dereference. We use the base type here because
5947 -- within an instance these may be subtypes.
5949 -- The dereference is added either in Analyze_Call or here. Should
5950 -- be consolidated ???
5959 -- Check that a call to Current_Task does not occur in an entry body
5962 declare
5965 begin
5967 loop
5970 -- Exclude calls that occur within the default of a formal
5971 -- parameter of the entry, since those are evaluated outside
5972 -- of the body.
5979 then
5982 Error_Msg_NE
5996 -- Check that a procedure call does not occur in the context of the
5997 -- entry call statement of a conditional or timed entry call. Note that
5998 -- the case of a call to a subprogram renaming of an entry will also be
5999 -- rejected. The test for N not being an N_Entry_Call_Statement is
6000 -- defensive, covering the possibility that the processing of entry
6001 -- calls might reach this point due to later modifications of the code
6002 -- above.
6007 then
6011 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6012 -- for a procedure_or_entry_call, the procedure_name or
6013 -- procedure_prefix of the procedure_call_statement shall denote
6014 -- an entry renamed by a procedure, or (a view of) a primitive
6015 -- subprogram of a limited interface whose first parameter is
6016 -- a controlling parameter.
6021 then
6022 Error_Msg_N
6027 -- If the SPARK_05 restriction is active, we are not allowed
6028 -- to have a call to a subprogram before we see its completion.
6033 -- Don't flag strange internal calls
6038 -- Only flag calls in extended main source
6043 -- Exclude enumeration literals from this processing
6046 then
6047 Check_SPARK_05_Restriction
6051 -- Check that this is not a call to a protected procedure or entry from
6052 -- within a protected function.
6056 -- Freeze the subprogram name if not in a spec-expression. Note that
6057 -- we freeze procedure calls as well as function calls. Procedure calls
6058 -- are not frozen according to the rules (RM 13.14(14)) because it is
6059 -- impossible to have a procedure call to a non-frozen procedure in
6060 -- pure Ada, but in the code that we generate in the expander, this
6061 -- rule needs extending because we can generate procedure calls that
6062 -- need freezing.
6064 -- In Ada 2012, expression functions may be called within pre/post
6065 -- conditions of subsequent functions or expression functions. Such
6066 -- calls do not freeze when they appear within generated bodies,
6067 -- (including the body of another expression function) which would
6068 -- place the freeze node in the wrong scope. An expression function
6069 -- is frozen in the usual fashion, by the appearance of a real body,
6070 -- or at the end of a declarative part.
6073 and then not In_Spec_Expression
6075 and then
6078 then
6082 -- For a predefined operator, the type of the result is the type imposed
6083 -- by context, except for a predefined operation on universal fixed.
6084 -- Otherwise The type of the call is the type returned by the subprogram
6085 -- being called.
6092 -- If the subprogram returns an array type, and the context requires the
6093 -- component type of that array type, the node is really an indexing of
6094 -- the parameterless call. Resolve as such. A pathological case occurs
6095 -- when the type of the component is an access to the array type. In
6096 -- this case the call is truly ambiguous. If the call is to an intrinsic
6097 -- subprogram, it can't be an indexed component. This check is necessary
6098 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6099 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6100 -- pointers to the same array), the compiler gets confused and does an
6101 -- infinite recursion.
6104 and then
6107 or else
6110 and then
6113 then
6114 declare
6119 begin
6122 then
6123 Error_Msg_N
6125 else
6128 -- The called entity may be an explicit dereference, in which
6129 -- case there is no entity to set.
6137 or else
6139 and then
6141 then
6144 -- Indexed call to a parameterless function
6146 Index_Node :=
6148 Prefix =>
6151 else
6152 -- An Ada 2005 prefixed call to a primitive operation
6153 -- whose first parameter is the prefix. This prefix was
6154 -- prepended to the parameter list, which is actually a
6155 -- list of indexes. Remove the prefix in order to build
6156 -- the proper indexed component.
6158 Index_Node :=
6160 Prefix =>
6163 Parameter_Associations =>
6164 New_List
6169 -- Preserve the parenthesis count of the node
6173 -- Since we are correcting a node classification error made
6174 -- by the parser, we call Replace rather than Rewrite.
6186 -- Annotate the tree by creating a call marker in case
6187 -- the original call is transformed by expansion. The call
6188 -- marker is automatically saved for later examination by
6189 -- the ABE Processing phase.
6198 else
6199 -- If the called function is not declared in the main unit and it
6200 -- returns the limited view of type then use the available view (as
6201 -- is done in Try_Object_Operation) to prevent back-end confusion;
6202 -- for the function entity itself. The call must appear in a context
6203 -- where the nonlimited view is available. If the function entity is
6204 -- in the extended main unit then no action is needed, because the
6205 -- back end handles this case. In either case the type of the call
6206 -- is the nonlimited view.
6210 then
6217 else
6222 -- In the case where the call is to an overloaded subprogram, Analyze
6223 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6224 -- such a case Normalize_Actuals needs to be called once more to order
6225 -- the actuals correctly. Otherwise the call will have the ordering
6226 -- given by the last overloaded subprogram whether this is the correct
6227 -- one being called or not.
6234 -- In any case, call is fully resolved now. Reset Overload flag, to
6235 -- prevent subsequent overload resolution if node is analyzed again
6240 -- A Ghost entity must appear in a specific context
6246 -- If we are calling the current subprogram from immediately within its
6247 -- body, then that is the case where we can sometimes detect cases of
6248 -- infinite recursion statically. Do not try this in case restriction
6249 -- No_Recursion is in effect anyway, and do it only for source calls.
6254 -- Check violation of SPARK_05 restriction which does not permit
6255 -- a subprogram body to contain a call to the subprogram directly.
6259 then
6260 Check_SPARK_05_Restriction
6264 -- Issue warning for possible infinite recursion in the absence
6265 -- of the No_Recursion restriction.
6270 then
6271 -- Here we detected and flagged an infinite recursion, so we do
6272 -- not need to test the case below for further warnings. Also we
6273 -- are all done if we now have a raise SE node.
6279 -- If call is to immediately containing subprogram, then check for
6280 -- the case of a possible run-time detectable infinite recursion.
6282 else
6286 -- Although in general case, recursion is not statically
6287 -- checkable, the case of calling an immediately containing
6288 -- subprogram is easy to catch.
6292 -- If the recursive call is to a parameterless subprogram,
6293 -- then even if we can't statically detect infinite
6294 -- recursion, this is pretty suspicious, and we output a
6295 -- warning. Furthermore, we will try later to detect some
6296 -- cases here at run time by expanding checking code (see
6297 -- Detect_Infinite_Recursion in package Exp_Ch6).
6299 -- If the recursive call is within a handler, do not emit a
6300 -- warning, because this is a common idiom: loop until input
6301 -- is correct, catch illegal input in handler and restart.
6307 then
6308 -- For the case of a procedure call. We give the message
6309 -- only if the call is the first statement in a sequence
6310 -- of statements, or if all previous statements are
6311 -- simple assignments. This is simply a heuristic to
6312 -- decrease false positives, without losing too many good
6313 -- warnings. The idea is that these previous statements
6314 -- may affect global variables the procedure depends on.
6315 -- We also exclude raise statements, that may arise from
6316 -- constraint checks and are probably unrelated to the
6317 -- intended control flow.
6321 then
6322 declare
6324 begin
6328 N_Raise_Constraint_Error)
6329 then
6338 -- Do not give warning if we are in a conditional context
6340 declare
6342 begin
6348 then
6353 -- Here warning is to be issued
6369 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6373 -- If subprogram name is a predefined operator, it was given in
6374 -- functional notation. Replace call node with operator node, so
6375 -- that actuals can be resolved appropriately.
6383 then
6389 -- Create a transient scope if the resulting type requires it
6391 -- There are several notable exceptions:
6393 -- a) In init procs, the transient scope overhead is not needed, and is
6394 -- even incorrect when the call is a nested initialization call for a
6395 -- component whose expansion may generate adjust calls. However, if the
6396 -- call is some other procedure call within an initialization procedure
6397 -- (for example a call to Create_Task in the init_proc of the task
6398 -- run-time record) a transient scope must be created around this call.
6400 -- b) Enumeration literal pseudo-calls need no transient scope
6402 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6403 -- functions) do not use the secondary stack even though the return
6404 -- type may be unconstrained.
6406 -- d) Calls to a build-in-place function, since such functions may
6407 -- allocate their result directly in a target object, and cases where
6408 -- the result does get allocated in the secondary stack are checked for
6409 -- within the specialized Exp_Ch6 procedures for expanding those
6410 -- build-in-place calls.
6412 -- e) Calls to inlinable expression functions do not use the secondary
6413 -- stack (since the call will be replaced by its returned object).
6415 -- f) If the subprogram is marked Inline_Always, then even if it returns
6416 -- an unconstrained type the call does not require use of the secondary
6417 -- stack. However, inlining will only take place if the body to inline
6418 -- is already present. It may not be available if e.g. the subprogram is
6419 -- declared in a child instance.
6425 then
6432 then
6435 elsif Expander_Active
6438 then
6441 -- If the call appears within the bounds of a loop, it will be
6442 -- rewritten and reanalyzed, nothing left to do here.
6449 -- A protected function cannot be called within the definition of the
6450 -- enclosing protected type, unless it is part of a pre/postcondition
6451 -- on another protected operation. This may appear in the entry wrapper
6452 -- created for an entry with preconditions.
6457 and then not In_Spec_Expression
6459 then
6460 Error_Msg_NE
6464 -- Propagate interpretation to actuals, and add default expressions
6465 -- where needed.
6470 -- Overloaded literals are rewritten as function calls, for purpose of
6471 -- resolution. After resolution, we can replace the call with the
6472 -- literal itself.
6478 -- Avoid validation, since it is a static function call
6484 -- If the subprogram is not global, then kill all saved values and
6485 -- checks. This is a bit conservative, since in many cases we could do
6486 -- better, but it is not worth the effort. Similarly, we kill constant
6487 -- values. However we do not need to do this for internal entities
6488 -- (unless they are inherited user-defined subprograms), since they
6489 -- are not in the business of molesting local values.
6491 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6492 -- kill all checks and values for calls to global subprograms. This
6493 -- takes care of the case where an access to a local subprogram is
6494 -- taken, and could be passed directly or indirectly and then called
6495 -- from almost any context.
6497 -- Note: we do not do this step till after resolving the actuals. That
6498 -- way we still take advantage of the current value information while
6499 -- scanning the actuals.
6501 -- We suppress killing values if we are processing the nodes associated
6502 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6503 -- type kills all the values as part of analyzing the code that
6504 -- initializes the dispatch tables.
6508 or else Suppress_Value_Tracking_On_Call
6513 then
6514 Kill_Current_Values;
6517 -- If we are warning about unread OUT parameters, this is the place to
6518 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6519 -- after the above call to Kill_Current_Values (since that call clears
6520 -- the Last_Assignment field of all local variables).
6525 then
6526 declare
6530 begin
6540 then
6550 -- If the subprogram is a primitive operation, check whether or not
6551 -- it is a correct dispatching call.
6555 then
6560 and then not In_Instance
6561 then
6565 -- If this is a dispatching call, generate the appropriate reference,
6566 -- for better source navigation in GPS.
6570 then
6573 -- Normal case, not a dispatching call: generate a call reference
6575 else
6583 -- Check for violation of restriction No_Specific_Termination_Handlers
6584 -- and warn on a potentially blocking call to Abort_Task.
6588 or else
6590 then
6597 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6598 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6599 -- need to check the second argument to determine whether it is an
6600 -- absolute or relative timing event.
6605 then
6609 -- Issue an error for a call to an eliminated subprogram. This routine
6610 -- will not perform the check if the call appears within a default
6611 -- expression.
6615 -- In formal mode, the primitive operations of a tagged type or type
6616 -- extension do not include functions that return the tagged type.
6622 then
6626 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6627 -- class-wide and the call dispatches on result in a context that does
6628 -- not provide a tag, the call raises Program_Error.
6631 and then In_Instance
6636 then
6637 -- Verify that none of the formals are controlling
6639 declare
6643 begin
6665 -- Check for calling a function with OUT or IN OUT parameter when the
6666 -- calling context (us right now) is not Ada 2012, so does not allow
6667 -- OUT or IN OUT parameters in function calls. Functions declared in
6668 -- a predefined unit are OK, as they may be called indirectly from a
6669 -- user-declared instantiation.
6675 then
6680 -- Check the dimensions of the actuals in the call. For function calls,
6681 -- propagate the dimensions from the returned type to N.
6685 -- All done, evaluate call and deal with elaboration issues
6693 -- Annotate the tree by creating a call marker in case the original call
6694 -- is transformed by expansion. The call marker is automatically saved
6695 -- for later examination by the ABE Processing phase.
6699 -- In GNATprove mode, expansion is disabled, but we want to inline some
6700 -- subprograms to facilitate formal verification. Indirect calls through
6701 -- a subprogram type or within a generic cannot be inlined. Inlining is
6702 -- performed only for calls subject to SPARK_Mode on.
6704 if GNATprove_Mode
6707 and then not Inside_A_Generic
6708 then
6715 -- Nothing to do if the subprogram is not eligible for inlining in
6716 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6720 or else Debug_Flag_M
6721 then
6724 -- Calls cannot be inlined inside assertions, as GNATprove treats
6725 -- assertions as logic expressions. Only issue a message when the
6726 -- body has been seen, otherwise this leads to spurious messages
6727 -- on expression functions.
6731 Cannot_Inline
6735 -- Calls cannot be inlined inside default expressions
6738 Cannot_Inline
6741 -- Inlining should not be performed during preanalysis
6745 -- Do not inline calls inside expression functions or functions
6746 -- generated by the front end for subtype predicates, as this
6747 -- would prevent interpreting them as logical formulas in
6748 -- GNATprove. Only issue a message when the body has been seen,
6749 -- otherwise this leads to spurious messages on callees that
6750 -- are themselves expression functions.
6753 and then
6758 then
6761 then
6763 Cannot_Inline
6768 Cannot_Inline
6773 Cannot_Inline
6777 else
6778 Cannot_Inline
6784 -- With the one-pass inlining technique, a call cannot be
6785 -- inlined if the corresponding body has not been seen yet.
6788 Cannot_Inline
6791 -- Nothing to do if there is no body to inline, indicating that
6792 -- the subprogram is not suitable for inlining in GNATprove
6793 -- mode.
6798 -- Calls cannot be inlined inside potentially unevaluated
6799 -- expressions, as this would create complex actions inside
6800 -- expressions, that are not handled by GNATprove.
6803 Cannot_Inline
6807 -- Do not inline calls which would possibly lead to missing a
6808 -- type conversion check on an input parameter.
6811 Cannot_Inline
6815 -- Otherwise, inline the call
6817 else
6829 -----------------------------
6830 -- Resolve_Case_Expression --
6831 -----------------------------
6839 begin
6851 -- When the expression is of a scalar subtype different from the
6852 -- result subtype, then insert a conversion to ensure the generation
6853 -- of a constraint check.
6863 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6864 -- dynamically tagged must be known statically.
6872 Error_Msg_N
6886 -------------------------------
6887 -- Resolve_Character_Literal --
6888 -------------------------------
6894 begin
6895 -- Verify that the character does belong to the type of the context
6900 -- Wide_Wide_Character literals must always be defined, since the set
6901 -- of wide wide character literals is complete, i.e. if a character
6902 -- literal is accepted by the parser, then it is OK for wide wide
6903 -- character (out of range character literals are rejected).
6908 -- Always accept character literal for type Any_Character, which
6909 -- occurs in error situations and in comparisons of literals, both
6910 -- of which should accept all literals.
6915 -- For Standard.Character or a type derived from it, check that the
6916 -- literal is in range.
6923 -- For Standard.Wide_Character or a type derived from it, check that the
6924 -- literal is in range.
6931 -- If the entity is already set, this has already been resolved in a
6932 -- generic context, or comes from expansion. Nothing else to do.
6937 -- Otherwise we have a user defined character type, and we can use the
6938 -- standard visibility mechanisms to locate the referenced entity.
6940 else
6953 -- If we fall through, then the literal does not match any of the
6954 -- entries of the enumeration type. This isn't just a constraint error
6955 -- situation, it is an illegality (see RM 4.2).
6957 Error_Msg_NE
6961 ---------------------------
6962 -- Resolve_Comparison_Op --
6963 ---------------------------
6965 -- Context requires a boolean type, and plays no role in resolution.
6966 -- Processing identical to that for equality operators. The result type is
6967 -- the base type, which matters when pathological subtypes of booleans with
6968 -- limited ranges are used.
6975 begin
6976 -- If this is an intrinsic operation which is not predefined, use the
6977 -- types of its declared arguments to resolve the possibly overloaded
6978 -- operands. Otherwise the operands are unambiguous and specify the
6979 -- expected type.
6984 else
6995 -- Skip remaining processing if already set to Any_Type
7001 -- Deal with other error cases
7005 T = Any_Character
7006 then
7009 else
7017 -- Resolve the operands if types OK
7026 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
7027 -- types or array types except String.
7030 Check_SPARK_05_Restriction
7035 then
7036 Check_SPARK_05_Restriction
7040 -- Check comparison on unordered enumeration
7044 Error_Msg_NE
7051 -- Evaluate the relation (note we do this after the above check since
7052 -- this Eval call may change N to True/False. Skip this evaluation
7053 -- inside assertions, in order to keep assertions as written by users
7054 -- for tools that rely on these, e.g. GNATprove for loop invariants.
7055 -- Except evaluation is still performed even inside assertions for
7056 -- comparisons between values of universal type, which are useless
7057 -- for static analysis tools, and not supported even by GNATprove.
7061 and then
7063 then
7068 -----------------------------------------
7069 -- Resolve_Discrete_Subtype_Indication --
7070 -----------------------------------------
7072 procedure Resolve_Discrete_Subtype_Indication
7075 is
7079 begin
7087 else
7097 Error_Msg_NE
7100 -- Rewrite the constraint as a range of Typ
7101 -- to allow compilation to proceed further.
7113 else
7117 -- Additionally, we must check that the bounds are compatible
7118 -- with the given subtype, which might be different from the
7119 -- type of the context.
7123 -- ??? If the above check statically detects a Constraint_Error
7124 -- it replaces the offending bound(s) of the range R with a
7125 -- Constraint_Error node. When the itype which uses these bounds
7126 -- is frozen the resulting call to Duplicate_Subexpr generates
7127 -- a new temporary for the bounds.
7129 -- Unfortunately there are other itypes that are also made depend
7130 -- on these bounds, so when Duplicate_Subexpr is called they get
7131 -- a forward reference to the newly created temporaries and Gigi
7132 -- aborts on such forward references. This is probably sign of a
7133 -- more fundamental problem somewhere else in either the order of
7134 -- itype freezing or the way certain itypes are constructed.
7136 -- To get around this problem we call Remove_Side_Effects right
7137 -- away if either bounds of R are a Constraint_Error.
7139 declare
7143 begin
7159 -------------------------
7160 -- Resolve_Entity_Name --
7161 -------------------------
7163 -- Used to resolve identifiers and expanded names
7166 function Is_Assignment_Or_Object_Expression
7169 -- Determine whether node Context denotes an assignment statement or an
7170 -- object declaration whose expression is node Expr.
7172 ----------------------------------------
7173 -- Is_Assignment_Or_Object_Expression --
7174 ----------------------------------------
7176 function Is_Assignment_Or_Object_Expression
7179 is
7180 begin
7182 N_Object_Declaration)
7184 then
7187 -- Check whether a construct that yields a name is the expression of
7188 -- an assignment statement or an object declaration.
7191 N_Explicit_Dereference,
7192 N_Indexed_Component,
7193 N_Selected_Component,
7194 N_Slice)
7196 or else
7198 N_Unchecked_Type_Conversion)
7200 then
7201 return
7202 Is_Assignment_Or_Object_Expression
7206 -- Otherwise the context is not an assignment statement or an object
7207 -- declaration.
7209 else
7214 -- Local variables
7219 -- Start of processing for Resolve_Entity_Name
7221 begin
7222 -- If garbage from errors, set to Any_Type and return
7229 -- Replace named numbers by corresponding literals. Note that this is
7230 -- the one case where Resolve_Entity_Name must reset the Etype, since
7231 -- it is currently marked as universal.
7241 -- For enumeration literals, we need to make sure that a proper style
7242 -- check is done, since such literals are overloaded, and thus we did
7243 -- not do a style check during the first phase of analysis.
7249 -- Case of (sub)type name appearing in a context where an expression
7250 -- is expected. This is legal if occurrence is a current instance.
7251 -- See RM 8.6 (17/3).
7257 -- Any other use is an error
7259 else
7260 Error_Msg_N
7264 -- Check discriminant use if entity is discriminant in current scope,
7265 -- i.e. discriminant of record or concurrent type currently being
7266 -- analyzed. Uses in corresponding body are unrestricted.
7271 then
7274 -- A parameterless generic function cannot appear in a context that
7275 -- requires resolution.
7280 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7281 -- array types (i.e. bounds and length) are legal.
7289 or else Is_Assignment_Or_Object_Expression
7292 then
7297 -- In all other cases, just do the possible static evaluation
7299 else
7300 -- A deferred constant that appears in an expression must have a
7301 -- completion, unless it has been removed by in-place expansion of
7302 -- an aggregate. A constant that is a renaming does not need
7303 -- initialization.
7309 and then not In_Spec_Expression
7312 then
7316 then
7318 else
7319 Error_Msg_N
7329 -- When the entity appears in a parameter association, retrieve the
7330 -- related subprogram call.
7338 -- The following checks are only relevant when SPARK_Mode is on as
7339 -- they are not standard Ada legality rules.
7343 -- An effectively volatile object subject to enabled properties
7344 -- Async_Writers or Effective_Reads must appear in non-interfering
7345 -- context (SPARK RM 7.1.3(12)).
7352 then
7353 SPARK_Msg_N
7358 -- Check for possible elaboration issues with respect to reads of
7359 -- variables. The act of renaming the variable is not considered a
7360 -- read as it simply establishes an alias.
7362 if Legacy_Elaboration_Checks
7364 and then Dynamic_Elaboration_Checks
7366 then
7371 -- The variable may eventually become a constituent of a single
7372 -- protected/task type. Record the reference now and verify its
7373 -- legality when analyzing the contract of the variable
7374 -- (SPARK RM 9.3).
7380 -- A Ghost entity must appear in a specific context
7387 -- We may be resolving an entity within expanded code, so a reference to
7388 -- an entity should be ignored when calculating effective use clauses to
7389 -- avoid inappropriate marking.
7396 -------------------
7397 -- Resolve_Entry --
7398 -------------------
7410 -- If the bounds of the entry family being called depend on task
7411 -- discriminants, build a new index subtype where a discriminant is
7412 -- replaced with the value of the discriminant of the target task.
7413 -- The target task is the prefix of the entry name in the call.
7415 -----------------------
7416 -- Actual_Index_Type --
7417 -----------------------
7427 -- If the bound is given by a discriminant, replace with a reference
7428 -- to the discriminant of the same name in the target task. If the
7429 -- entry name is the target of a requeue statement and the entry is
7430 -- in the current protected object, the bound to be used is the
7431 -- discriminal of the object (see Apply_Range_Checks for details of
7432 -- the transformation).
7434 -----------------------------
7435 -- Actual_Discriminant_Ref --
7436 -----------------------------
7442 begin
7447 then
7453 then
7454 -- Note: here Bound denotes a discriminant of the corresponding
7455 -- record type tskV, whose discriminal is a formal of the
7456 -- init-proc tskVIP. What we want is the body discriminal,
7457 -- which is associated to the discriminant of the original
7458 -- concurrent type tsk.
7460 return New_Occurrence_Of
7463 else
7464 Ref :=
7474 -- Start of processing for Actual_Index_Type
7476 begin
7479 then
7482 else
7496 -- Start of processing for Resolve_Entry
7498 begin
7499 -- Find name of entry being called, and resolve prefix of name with its
7500 -- own type. The prefix can be overloaded, and the name and signature of
7501 -- the entry must be taken into account.
7505 -- Case of dealing with entry family within the current tasks
7509 else
7515 -- Entry call to an entry (or entry family) in the current task. This
7516 -- is legal even though the task will deadlock. Rewrite as call to
7517 -- current task.
7519 -- This can also be a call to an entry in an enclosing task. If this
7520 -- is a single task, we have to retrieve its name, because the scope
7521 -- of the entry is the task type, not the object. If the enclosing
7522 -- task is a task type, the identity of the task is given by its own
7523 -- self variable.
7525 -- Finally this can be a requeue on an entry of the same task or
7526 -- protected object.
7533 then
7534 -- S is an enclosing task or protected object. The concurrent
7535 -- declaration has been converted into a type declaration, and
7536 -- the object itself has an object declaration that follows
7537 -- the type in the same declarative part.
7549 -- Call to current task. Will be transformed into call to Self
7556 New_N :=
7559 Selector_Name =>
7566 then
7567 -- Use the entry name (which must be unique at this point) to find
7568 -- the prefix that returns the corresponding task/protected type.
7570 declare
7576 begin
7598 -- Generate a reference for the index when it denotes an entity
7604 -- Up to this point the expression could have been the actual in a
7605 -- simple entry call, and be given by a named association.
7609 else
7615 ------------------------
7616 -- Resolve_Entry_Call --
7617 ------------------------
7628 begin
7629 -- We kill all checks here, because it does not seem worth the effort to
7630 -- do anything better, an entry call is a big operation.
7632 Kill_All_Checks;
7634 -- Processing of the name is similar for entry calls and protected
7635 -- operation calls. Once the entity is determined, we can complete
7636 -- the resolution of the actuals.
7638 -- The selector may be overloaded, in the case of a protected object
7639 -- with overloaded functions. The type of the context is used for
7640 -- resolution.
7645 then
7646 declare
7650 begin
7669 -- Simple entry or protected operation call
7682 -- Call to member of entry family
7689 -- We cannot in general check the maximum depth of protected entry calls
7690 -- at compile time. But we can tell that any protected entry call at all
7691 -- violates a specified nesting depth of zero.
7697 -- Use context type to disambiguate a protected function that can be
7698 -- called without actuals and that returns an array type, and where the
7699 -- argument list may be an indexing of the returned value.
7704 and then
7710 and then
7711 Covers
7714 then
7715 declare
7718 begin
7719 Index_Node :=
7721 Prefix =>
7725 -- Since we are correcting a node classification error made by the
7726 -- parser, we call Replace rather than Rewrite.
7739 then
7740 -- Note the entity being called before rewriting the call, so that
7741 -- it appears used at this point.
7745 -- Rewrite as call to the precondition wrapper, adding the task
7746 -- object to the list of actuals. If the call is to a member of an
7747 -- entry family, include the index as well.
7749 declare
7753 begin
7762 New_Call :=
7764 Name =>
7769 -- Preanalyze and resolve new call. Current procedure is called
7770 -- from Resolve_Call, after which expansion will take place.
7777 -- The operation name may have been overloaded. Order the actuals
7778 -- according to the formals of the resolved entity, and set the return
7779 -- type to that of the operation.
7786 -- Reset the Is_Overloaded flag, since resolution is now completed
7788 -- Simple entry call
7793 -- Call to a member of an entry family
7803 -- Create a call reference to the entry
7811 -- Verify that a procedure call cannot masquerade as an entry
7812 -- call where an entry call is expected.
7817 then
7822 then
7827 then
7832 -- After resolution, entry calls and protected procedure calls are
7833 -- changed into entry calls, for expansion. The structure of the node
7834 -- does not change, so it can safely be done in place. Protected
7835 -- function calls must keep their structure because they are
7836 -- subexpressions.
7840 -- A protected operation that is not a function may modify the
7841 -- corresponding object, and cannot apply to a constant. If this
7842 -- is an internal call, the prefix is the type itself.
7848 then
7849 Error_Msg_N
7851 Entry_Name);
7854 declare
7857 begin
7858 Entry_Call :=
7863 -- Inherit relevant attributes from the original call
7865 Set_First_Named_Actual
7868 Set_Is_Elaboration_Checks_OK_Node
7871 Set_Is_Elaboration_Warnings_OK_Node
7874 Set_Is_SPARK_Mode_On_Node
7881 -- Protected functions can return on the secondary stack, in which case
7882 -- we must trigger the transient scope mechanism.
7884 elsif Expander_Active
7886 then
7891 -------------------------
7892 -- Resolve_Equality_Op --
7893 -------------------------
7895 -- Both arguments must have the same type, and the boolean context does
7896 -- not participate in the resolution. The first pass verifies that the
7897 -- interpretation is not ambiguous, and the type of the left argument is
7898 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7899 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7900 -- though they carry a single (universal) type. Diagnose this case here.
7908 -- The resolution rule for if expressions requires that each such must
7909 -- have a unique type. This means that if several dependent expressions
7910 -- are of a non-null anonymous access type, and the context does not
7911 -- impose an expected type (as can be the case in an equality operation)
7912 -- the expression must be rejected.
7915 -- Attempt to explain the nature of a redundant comparison with True. If
7916 -- the expression N is too complex, this routine issues a general error
7917 -- message.
7920 -- In the case of allocators and access attributes, the context must
7921 -- provide an indication of the specific access type to be used. If
7922 -- one operand is of such a "generic" access type, check whether there
7923 -- is a specific visible access type that has the same designated type.
7924 -- This is semantically dubious, and of no interest to any real code,
7925 -- but c48008a makes it all worthwhile.
7927 -------------------------
7928 -- Check_If_Expression --
7929 -------------------------
7935 begin
7942 then
7948 ------------------------
7949 -- Explain_Redundancy --
7950 ------------------------
7957 begin
7960 -- Strip the operand down to an entity
7962 loop
7965 else
7970 -- The construct denotes an entity
7975 -- Do not generate an error message when the comparison is done
7976 -- against the enumeration literal Standard.True.
7980 -- Build a customized error message
8007 -- The construct is too complex to disect, issue a general message
8009 else
8014 -----------------------------
8015 -- Find_Unique_Access_Type --
8016 -----------------------------
8023 begin
8025 E_Access_Attribute_Type)
8026 then
8030 E_Access_Attribute_Type)
8031 then
8033 else
8045 then
8058 -- Start of processing for Resolve_Equality_Op
8060 begin
8071 T = Any_Character
8072 then
8075 else
8084 then
8093 -- If expressions must have a single type, and if the context does
8094 -- not impose one the dependent expressions cannot be anonymous
8095 -- access types.
8097 -- Why no similar processing for case expressions???
8101 E_Anonymous_Access_Subprogram_Type)
8103 E_Anonymous_Access_Subprogram_Type)
8104 then
8112 -- In SPARK, equality operators = and /= for array types other than
8113 -- String are only defined when, for each index position, the
8114 -- operands have equal static bounds.
8118 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8119 -- operation if not needed.
8127 then
8128 Check_SPARK_05_Restriction
8133 -- If the unique type is a class-wide type then it will be expanded
8134 -- into a dispatching call to the predefined primitive. Therefore we
8135 -- check here for potential violation of such restriction.
8141 -- Only warn for redundant equality comparison to True for objects
8142 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8143 -- other expressions, it may be a matter of preference to write
8144 -- "Expr = True" or "Expr".
8146 if Warn_On_Redundant_Constructs
8151 and then
8153 or else
8155 then
8156 Error_Msg_N -- CODEFIX
8166 -- If this is an inequality, it may be the implicit inequality
8167 -- created for a user-defined operation, in which case the corres-
8168 -- ponding equality operation is not intrinsic, and the operation
8169 -- cannot be constant-folded. Else fold.
8174 or else Is_Intrinsic_Subprogram
8176 then
8182 then
8186 -- Ada 2005: If one operand is an anonymous access type, convert the
8187 -- other operand to it, to ensure that the underlying types match in
8188 -- the back-end. Same for access_to_subprogram, and the conversion
8189 -- verifies that the types are subtype conformant.
8191 -- We apply the same conversion in the case one of the operands is a
8192 -- private subtype of the type of the other.
8194 -- Why the Expander_Active test here ???
8196 if Expander_Active
8197 and then
8199 E_Anonymous_Access_Subprogram_Type)
8201 then
8221 ----------------------------------
8222 -- Resolve_Explicit_Dereference --
8223 ----------------------------------
8231 -- The candidate prefix type, if overloaded
8236 begin
8240 -- A useful optimization: check whether the dereference denotes an
8241 -- element of a container, and if so rewrite it as a call to the
8242 -- corresponding Element function.
8244 -- Disabled for now, on advice of ARG. A more restricted form of the
8245 -- predicate might be acceptable ???
8247 -- if Is_Container_Element (N) then
8248 -- return;
8249 -- end if;
8253 -- Use the context type to select the prefix that has the correct
8254 -- designated type. Keep the first match, which will be the inner-
8255 -- most.
8262 then
8267 -- Remove access types that do not match, but preserve access
8268 -- to subprogram interpretations, in case a further dereference
8269 -- is needed (see below).
8282 else
8283 -- If no interpretation covers the designated type of the prefix,
8284 -- this is the pathological case where not all implementations of
8285 -- the prefix allow the interpretation of the node as a call. Now
8286 -- that the expected type is known, Remove other interpretations
8287 -- from prefix, rewrite it as a call, and resolve again, so that
8288 -- the proper call node is generated.
8299 New_N :=
8301 Name =>
8312 -- If not overloaded, resolve P with its own type
8314 else
8318 -- If the prefix might be null, add an access check
8322 then
8326 -- If the designated type is a packed unconstrained array type, and the
8327 -- explicit dereference is not in the context of an attribute reference,
8328 -- then we must compute and set the actual subtype, since it is needed
8329 -- by Gigi. The reason we exclude the attribute case is that this is
8330 -- handled fine by Gigi, and in fact we use such attributes to build the
8331 -- actual subtype. We also exclude generated code (which builds actual
8332 -- subtypes directly if they are needed).
8339 then
8345 -- Note: No Eval processing is required for an explicit dereference,
8346 -- because such a name can never be static.
8350 -------------------------------------
8351 -- Resolve_Expression_With_Actions --
8352 -------------------------------------
8355 begin
8358 -- If N has no actions, and its expression has been constant folded,
8359 -- then rewrite N as just its expression. Note, we can't do this in
8360 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8361 -- Expression (N) to be expanded again.
8365 then
8370 ----------------------------------
8371 -- Resolve_Generalized_Indexing --
8372 ----------------------------------
8380 begin
8381 -- In ASIS mode, propagate the information about the indexes back to
8382 -- to the original indexing node. The generalized indexing is either
8383 -- a function call, or a dereference of one. The actuals include the
8384 -- prefix of the original node, which is the container expression.
8393 loop
8402 -- If expression is to be reanalyzed, reset Generalized_Indexing
8403 -- to recreate call node, as is the case when the expression is
8404 -- part of an expression function.
8413 else
8419 ---------------------------
8420 -- Resolve_If_Expression --
8421 ---------------------------
8430 begin
8431 -- Defend against malformed expressions
8449 -- When the "then" expression is of a scalar subtype different from the
8450 -- result subtype, then insert a conversion to ensure the generation of
8451 -- a constraint check. The same is done for the else part below, again
8452 -- comparing subtypes rather than base types.
8459 -- If ELSE expression present, just resolve using the determined type
8460 -- If type is universal, resolve to any member of the class.
8469 else
8479 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8480 -- dynamically tagged must be known statically.
8485 then
8491 -- If no ELSE expression is present, root type must be Standard.Boolean
8492 -- and we provide a Standard.True result converted to the appropriate
8493 -- Boolean type (in case it is a derived boolean type).
8496 Else_Expr :=
8501 else
8515 -------------------------------
8516 -- Resolve_Indexed_Component --
8517 -------------------------------
8525 begin
8533 -- Use the context type to select the prefix that yields the correct
8534 -- component type.
8536 declare
8543 begin
8550 and then
8551 Covers
8554 then
8563 else
8569 else
8580 else
8587 -- If prefix is access type, dereference to get real array type.
8588 -- Note: we do not apply an access check because the expander always
8589 -- introduces an explicit dereference, and the check will happen there.
8595 -- If name was overloaded, set component type correctly now
8596 -- If a misplaced call to an entry family (which has no index types)
8597 -- return. Error will be diagnosed from calling context.
8601 else
8608 -- The prefix may have resolved to a string literal, in which case its
8609 -- etype has a special representation. This is only possible currently
8610 -- if the prefix is a static concatenation, written in functional
8611 -- notation.
8616 else
8623 else
8634 -- Do not generate the warning on suspicious index if we are analyzing
8635 -- package Ada.Tags; otherwise we will report the warning with the
8636 -- Prims_Ptr field of the dispatch table.
8639 or else not
8641 Ada_Tags)
8642 then
8647 -- If the array type is atomic, and the component is not atomic, then
8648 -- this is worth a warning, since we have a situation where the access
8649 -- to the component may cause extra read/writes of the atomic array
8650 -- object, or partial word accesses, which could be unexpected.
8656 and then Has_Atomic_Components
8659 then
8660 Error_Msg_N
8662 Error_Msg_N
8667 -----------------------------
8668 -- Resolve_Integer_Literal --
8669 -----------------------------
8672 begin
8677 --------------------------------
8678 -- Resolve_Intrinsic_Operator --
8679 --------------------------------
8688 -- If the operand is a literal, it cannot be the expression in a
8689 -- conversion. Use a qualified expression instead.
8691 ---------------------
8692 -- Convert_Operand --
8693 ---------------------
8699 begin
8701 Res :=
8707 else
8714 -- Start of processing for Resolve_Intrinsic_Operator
8716 begin
8717 -- We must preserve the original entity in a generic setting, so that
8718 -- the legality of the operation can be verified in an instance.
8733 -- If the result or operand types are private, rewrite with unchecked
8734 -- conversions on the operands and the result, to expose the proper
8735 -- underlying numeric type.
8740 then
8745 else
8766 then
8767 -- Add explicit conversion where needed, and save interpretations in
8768 -- case operands are overloaded.
8775 else
8781 else
8791 else
8796 --------------------------------------
8797 -- Resolve_Intrinsic_Unary_Operator --
8798 --------------------------------------
8800 procedure Resolve_Intrinsic_Unary_Operator
8803 is
8808 begin
8827 else
8832 ------------------------
8833 -- Resolve_Logical_Op --
8834 ------------------------
8839 begin
8842 -- Predefined operations on scalar types yield the base type. On the
8843 -- other hand, logical operations on arrays yield the type of the
8844 -- arguments (and the context).
8848 else
8852 -- The following test is required because the operands of the operation
8853 -- may be literals, in which case the resulting type appears to be
8854 -- compatible with a signed integer type, when in fact it is compatible
8855 -- only with modular types. If the context itself is universal, the
8856 -- operation is illegal.
8864 Error_Msg_N
8872 then
8876 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8877 -- is active and the result type is standard Boolean (do not mess with
8878 -- ops that return a nonstandard Boolean type, because something strange
8879 -- is going on).
8881 -- Note: you might expect this replacement to be done during expansion,
8882 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8883 -- is used, no part of the right operand of an "and" or "or" operator
8884 -- should be executed if the left operand would short-circuit the
8885 -- evaluation of the corresponding "and then" or "or else". If we left
8886 -- the replacement to expansion time, then run-time checks associated
8887 -- with such operands would be evaluated unconditionally, due to being
8888 -- before the condition prior to the rewriting as short-circuit forms
8889 -- during expansion.
8891 if Short_Circuit_And_Or
8894 then
8895 -- Mark the corresponding putative SCO operator as truly a logical
8896 -- (and short-circuit) operator.
8909 -- Case of OR changed to OR ELSE
8911 else
8919 -- Return now, since analysis of the rewritten ops will take care of
8920 -- other reference bookkeeping and expression folding.
8935 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8936 -- only when both operands have same static lower and higher bounds. Of
8937 -- course the types have to match, so only check if operands are
8938 -- compatible and the node itself has no errors.
8942 then
8943 declare
8947 begin
8948 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8949 -- operation if not needed.
8956 then
8957 Check_SPARK_05_Restriction
8964 ---------------------------
8965 -- Resolve_Membership_Op --
8966 ---------------------------
8968 -- The context can only be a boolean type, and does not determine the
8969 -- arguments. Arguments should be unambiguous, but the preference rule for
8970 -- universal types applies.
8980 -- Analysis has determined a unique type for the left operand. Use it to
8981 -- resolve the disjuncts.
8983 ----------------------------
8984 -- Resolve_Set_Membership --
8985 ----------------------------
8991 begin
8992 -- If the left operand is overloaded, find type compatible with not
8993 -- overloaded alternative of the right operand.
9002 else
9007 -- Unclear how to resolve expression if all alternatives are also
9008 -- overloaded.
9014 else
9023 -- Alternative is an expression, a range
9024 -- or a subtype mark.
9028 then
9035 -- Check for duplicates for discrete case
9038 declare
9047 begin
9048 -- Loop checking duplicates. This is quadratic, but giant sets
9049 -- are unlikely in this context so it's a reasonable choice.
9056 N_Character_Literal)
9058 then
9075 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
9076 -- limited types, evaluation of a membership test uses the predefined
9077 -- equality for the type. This may be confusing to users, and the
9078 -- following warning appears useful for the most common case.
9082 then
9083 Error_Msg_NE
9085 Error_Msg_N
9090 -- Start of processing for Resolve_Membership_Op
9092 begin
9098 Resolve_Set_Membership;
9102 and then
9104 or else
9107 then
9110 -- Ada 2005 (AI-251): Support the following case:
9112 -- type I is interface;
9113 -- type T is tagged ...
9115 -- function Test (O : I'Class) is
9116 -- begin
9117 -- return O in T'Class.
9118 -- end Test;
9120 -- In this case we have nothing else to do. The membership test will be
9121 -- done at run time.
9127 then
9129 else
9133 -- If mixed-mode operations are present and operands are all literal,
9134 -- the only interpretation involves Duration, which is probably not
9135 -- the intention of the programmer.
9150 then
9156 else
9161 -- Here after resolving membership operation
9168 ------------------
9169 -- Resolve_Null --
9170 ------------------
9175 begin
9176 -- Handle restriction against anonymous null access values This
9177 -- restriction can be turned off using -gnatdj.
9179 -- Ada 2005 (AI-231): Remove restriction
9182 and then not Debug_Flag_J
9185 then
9186 -- In the common case of a call which uses an explicitly null value
9187 -- for an access parameter, give specialized error message.
9190 Error_Msg_N
9193 -- Standard message for all other cases (are there any?)
9195 else
9196 Error_Msg_N
9201 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9202 -- assignment to a null-excluding object.
9207 then
9210 -- Decide whether to generate an if_statement around our
9211 -- null-excluding check to avoid them on certain internal object
9212 -- declarations by looking at the type the current Init_Proc
9213 -- belongs to.
9215 -- Generate:
9216 -- if T1b_skip_null_excluding_check then
9217 -- [constraint_error "access check failed"]
9218 -- end if;
9220 if Needs_Conditional_Null_Excluding_Check
9222 then
9225 Condition =>
9227 New_External_Name
9229 Then_Statements =>
9230 New_List (
9234 -- Otherwise, simply create the check
9236 else
9241 else
9242 Insert_Action
9250 -- In a distributed context, null for a remote access to subprogram may
9251 -- need to be replaced with a special record aggregate. In this case,
9252 -- return after having done the transformation.
9257 then
9261 -- The null literal takes its type from the context
9266 -----------------------
9267 -- Resolve_Op_Concat --
9268 -----------------------
9272 -- We wish to avoid deep recursion, because concatenations are often
9273 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9274 -- operands nonrecursively until we find something that is not a simple
9275 -- concatenation (A in this case). We resolve that, and then walk back
9276 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9277 -- to do the rest of the work at each level. The Parent pointers allow
9278 -- us to avoid recursion, and thus avoid running out of memory. See also
9279 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9284 begin
9285 -- The following code is equivalent to:
9287 -- Resolve_Op_Concat_First (NN, Typ);
9288 -- Resolve_Op_Concat_Arg (N, ...);
9289 -- Resolve_Op_Concat_Rest (N, Typ);
9291 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9292 -- operand is a concatenation.
9294 -- Walk down left operands
9296 loop
9305 -- Now (given the above example) NN is A&B and Op1 is A
9307 -- First resolve Op1 ...
9311 -- ... then walk NN back up until we reach N (where we started), calling
9312 -- Resolve_Op_Concat_Rest along the way.
9314 loop
9321 Check_SPARK_05_Restriction
9326 ---------------------------
9327 -- Resolve_Op_Concat_Arg --
9328 ---------------------------
9330 procedure Resolve_Op_Concat_Arg
9335 is
9339 begin
9341 if Is_Comp
9345 then
9347 else
9351 -- If both Array & Array and Array & Component are visible, there is a
9352 -- potential ambiguity that must be reported.
9357 then
9361 -- If the operation is user-defined and not overloaded use its
9362 -- profile. The operation may be a renaming, in which case it has
9363 -- been rewritten, and we want the original profile.
9368 then
9370 Etype
9374 -- Otherwise an aggregate may match both the array type and the
9375 -- component type.
9377 else
9382 else
9386 then
9387 declare
9392 begin
9397 -- Special-case the error message when the overloading is
9398 -- caused by a function that yields an array and can be
9399 -- called without parameters.
9404 Error_Msg_NE
9406 Error_Msg_NE
9410 else
9418 or else
9420 then
9421 Error_Msg_N -- CODEFIX
9439 else
9444 else
9448 -- Concatenation is restricted in SPARK: each operand must be either a
9449 -- string literal, the name of a string constant, a static character or
9450 -- string expression, or another concatenation. Arg cannot be a
9451 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9452 -- separately on each final operand, past concatenation operations.
9456 Check_SPARK_05_Restriction
9464 then
9465 Check_SPARK_05_Restriction
9469 -- Do not issue error on an operand that is neither a character nor a
9470 -- string, as the error is issued in Resolve_Op_Concat.
9472 else
9479 -----------------------------
9480 -- Resolve_Op_Concat_First --
9481 -----------------------------
9488 begin
9489 -- The parser folds an enormous sequence of concatenations of string
9490 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9491 -- in the right operand. If the expression resolves to a predefined "&"
9492 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9493 -- we give an error. See P_Simple_Expression in Par.Ch4.
9498 then
9513 ----------------------------
9514 -- Resolve_Op_Concat_Rest --
9515 ----------------------------
9521 begin
9530 -- If this is not a static concatenation, but the result is a string
9531 -- type (and not an array of strings) ensure that static string operands
9532 -- have their subtypes properly constructed.
9536 then
9542 ----------------------
9543 -- Resolve_Op_Expon --
9544 ----------------------
9549 begin
9550 -- Catch attempts to do fixed-point exponentiation with universal
9551 -- operands, which is a case where the illegality is not caught during
9552 -- normal operator analysis. This is not done in preanalysis mode
9553 -- since the tree is not fully decorated during preanalysis.
9565 then
9575 then
9582 then
9586 -- We do the resolution using the base type, because intermediate values
9587 -- in expressions are always of the base type, not a subtype of it.
9592 -- For integer types, right argument must be in Natural range
9607 -- Evaluate the exponentiation operator for dimensioned type
9610 else
9614 -- Set overflow checking bit. Much cleverer code needed here eventually
9615 -- and perhaps the Resolve routines should be separated for the various
9616 -- arithmetic operations, since they will need different processing. ???
9625 --------------------
9626 -- Resolve_Op_Not --
9627 --------------------
9633 -- This function determines if the parent node is a boolean operator or
9634 -- operation (comparison op, membership test, or short circuit form) and
9635 -- the not in question is the left operand of this operation. Note that
9636 -- if the not is in parens, then false is returned.
9638 -----------------------
9639 -- Parent_Is_Boolean --
9640 -----------------------
9643 begin
9647 else
9649 when N_And_Then
9650 | N_In
9651 | N_Not_In
9652 | N_Op_And
9653 | N_Op_Eq
9654 | N_Op_Ge
9655 | N_Op_Gt
9656 | N_Op_Le
9657 | N_Op_Lt
9658 | N_Op_Ne
9659 | N_Op_Or
9660 | N_Op_Xor
9661 | N_Or_Else
9662 =>
9671 -- Start of processing for Resolve_Op_Not
9673 begin
9674 -- Predefined operations on scalar types yield the base type. On the
9675 -- other hand, logical operations on arrays yield the type of the
9676 -- arguments (and the context).
9680 else
9684 -- Straightforward case of incorrect arguments
9691 -- Special case of probable missing parens
9695 Error_Msg_N
9698 else
9699 Error_Msg_N
9706 -- OK resolution of NOT
9708 else
9709 -- Warn if non-boolean types involved. This is a case like not a < b
9710 -- where a and b are modular, where we will get (not a) < b and most
9711 -- likely not (a < b) was intended.
9713 if Warn_On_Questionable_Missing_Parens
9715 and then Parent_Is_Boolean
9716 then
9720 -- Warn on double negation if checking redundant constructs
9722 if Warn_On_Redundant_Constructs
9727 then
9731 -- Complete resolution and evaluation of NOT
9741 -----------------------------
9742 -- Resolve_Operator_Symbol --
9743 -----------------------------
9745 -- Nothing to be done, all resolved already
9751 begin
9755 ----------------------------------
9756 -- Resolve_Qualified_Expression --
9757 ----------------------------------
9765 begin
9768 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9769 -- operation if not needed.
9776 then
9777 Check_SPARK_05_Restriction
9781 -- A qualified expression requires an exact match of the type, class-
9782 -- wide matching is not allowed. However, if the qualifying type is
9783 -- specific and the expression has a class-wide type, it may still be
9784 -- okay, since it can be the result of the expansion of a call to a
9785 -- dispatching function, so we also have to check class-wideness of the
9786 -- type of the expression's original node.
9789 or else
9793 then
9797 -- If the target type is unconstrained, then we reset the type of the
9798 -- result from the type of the expression. For other cases, the actual
9799 -- subtype of the expression is the target type.
9803 then
9810 -- If we still have a qualified expression after the static evaluation,
9811 -- then apply a scalar range check if needed. The reason that we do this
9812 -- after the Eval call is that otherwise, the application of the range
9813 -- check may convert an illegal static expression and result in warning
9814 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9820 -- Finally, check whether a predicate applies to the target type. This
9821 -- comes from AI12-0100. As for type conversions, check the enclosing
9822 -- context to prevent an infinite expansion.
9828 or else
9830 then
9833 -- In the case of a qualified expression in an allocator, the check
9834 -- is applied when expanding the allocator, so avoid redundant check.
9838 then
9844 ------------------------------
9845 -- Resolve_Raise_Expression --
9846 ------------------------------
9849 begin
9853 else
9858 -------------------
9859 -- Resolve_Range --
9860 -------------------
9867 -- Returns True if N is of the form X'First .. X'Last where X is the
9868 -- same entity for both attributes.
9870 --------------------
9871 -- First_Last_Ref --
9872 --------------------
9878 begin
9883 then
9884 declare
9887 begin
9891 then
9900 -- Start of processing for Resolve_Range
9902 begin
9905 -- The lower bound should be in Typ. The higher bound can be in Typ's
9906 -- base type if the range is null. It may still be invalid if it is
9907 -- higher than the lower bound. This is checked later in the context in
9908 -- which the range appears.
9913 -- Reanalyze the lower bound after both bounds have been analyzed, so
9914 -- that the range is known to be static or not by now. This may trigger
9915 -- more compile-time evaluation, which is useful for static analysis
9916 -- with GNATprove. This is not needed for compilation or static analysis
9917 -- with CodePeer, as full expansion does that evaluation then.
9924 -- Check for inappropriate range on unordered enumeration type
9928 -- Exclude X'First .. X'Last if X is the same entity for both
9930 and then not First_Last_Ref
9931 then
9933 Error_Msg_NE
9940 -- We have to check the bounds for being within the base range as
9941 -- required for a non-static context. Normally this is automatic and
9942 -- done as part of evaluating expressions, but the N_Range node is an
9943 -- exception, since in GNAT we consider this node to be a subexpression,
9944 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9945 -- this, but that would put the test on the main evaluation path for
9946 -- expressions.
9951 -- Check for an ambiguous range over character literals. This will
9952 -- happen with a membership test involving only literals.
9960 -- If bounds are static, constant-fold them, so size computations are
9961 -- identical between front-end and back-end. Do not perform this
9962 -- transformation while analyzing generic units, as type information
9963 -- would be lost when reanalyzing the constant node in the instance.
9976 --------------------------
9977 -- Resolve_Real_Literal --
9978 --------------------------
9983 begin
9984 -- Special processing for fixed-point literals to make sure that the
9985 -- value is an exact multiple of small where this is required. We skip
9986 -- this for the universal real case, and also for generic types.
9992 then
9993 declare
10000 begin
10001 -- Case of literal is not an exact multiple of the Small
10005 -- For a source program literal for a decimal fixed-point type,
10006 -- this is statically illegal (RM 4.9(36)).
10011 then
10015 -- Generate a warning if literal from source
10018 and then Warn_On_Bad_Fixed_Value
10019 then
10020 Error_Msg_N
10022 N);
10025 -- Replace literal by a value that is the exact representation
10026 -- of a value of the type, i.e. a multiple of the small value,
10027 -- by truncation, since Machine_Rounds is false for all GNAT
10028 -- fixed-point types (RM 4.9(38)).
10038 -- In all cases, set the corresponding integer field
10044 -- Now replace the actual type by the expected type as usual
10050 -----------------------
10051 -- Resolve_Reference --
10052 -----------------------
10057 begin
10058 -- Replace general access with specific type
10066 -- If we are taking the reference of a volatile entity, then treat it as
10067 -- a potential modification of this entity. This is too conservative,
10068 -- but necessary because remove side effects can cause transformations
10069 -- of normal assignments into reference sequences that otherwise fail to
10070 -- notice the modification.
10077 --------------------------------
10078 -- Resolve_Selected_Component --
10079 --------------------------------
10094 -- Check whether this is the initialization of a component within an
10095 -- init proc (by assignment or call to another init proc). If true,
10096 -- there is no need for a discriminant check.
10098 --------------------
10099 -- Init_Component --
10100 --------------------
10103 begin
10104 return Inside_Init_Proc
10110 -- Start of processing for Resolve_Selected_Component
10112 begin
10115 -- Use the context type to select the prefix that has a selector
10116 -- of the correct name and type.
10124 else
10128 -- Locate selected component. For a private prefix the selector
10129 -- can denote a discriminant.
10133 -- The visible components of a class-wide type are those of
10134 -- the root type.
10144 then
10151 else
10155 Error_Msg_N
10160 else
10163 -- There may be an implicit dereference. Retrieve
10164 -- designated record type.
10168 else
10174 -- Resolution chooses the new interpretation.
10175 -- Find the component with the right name.
10180 loop
10197 -- There must be a legal interpretation at this point
10204 -- The type of the context and that of the component are
10205 -- compatible and in general identical, but if they are anonymous
10206 -- access-to-subprogram types, the relevant type is that of the
10207 -- component. This matters in Unnest_Subprograms mode, where the
10208 -- relevant context is the one in which the type is declared, not
10209 -- the point of use. This determines what activation record to use.
10215 else
10216 -- Resolve prefix with its type
10221 -- Generate cross-reference. We needed to wait until full overloading
10222 -- resolution was complete to do this, since otherwise we can't tell if
10223 -- we are an lvalue or not.
10227 else
10231 -- If prefix is an access type, the node will be transformed into an
10232 -- explicit dereference during expansion. The type of the node is the
10233 -- designated type of that of the prefix.
10238 else
10242 -- Set flag for expander if discriminant check required on a component
10243 -- appearing within a variant.
10249 and then
10252 and then not Init_Component
10253 then
10261 -- If the prefix is a record conversion, this may be a renamed
10262 -- discriminant whose bounds differ from those of the original
10263 -- one, so we must ensure that a range check is performed.
10268 then
10272 -- Note: No Eval processing is required, because the prefix is of a
10273 -- record type, or protected type, and neither can possibly be static.
10275 -- If the record type is atomic, and the component is non-atomic, then
10276 -- this is worth a warning, since we have a situation where the access
10277 -- to the component may cause extra read/writes of the atomic array
10278 -- object, or partial word accesses, both of which may be unexpected.
10284 then
10285 Error_Msg_N
10288 Error_Msg_N
10296 -------------------
10297 -- Resolve_Shift --
10298 -------------------
10305 begin
10306 -- We do the resolution using the base type, because intermediate values
10307 -- in expressions always are of the base type, not a subtype of it.
10320 ---------------------------
10321 -- Resolve_Short_Circuit --
10322 ---------------------------
10329 begin
10330 -- Ensure all actions associated with the left operand (e.g.
10331 -- finalization of transient objects) are fully evaluated locally within
10332 -- an expression with actions. This is particularly helpful for coverage
10333 -- analysis. However this should not happen in generics or if option
10334 -- Minimize_Expression_With_Actions is set.
10337 declare
10339 begin
10347 -- Set Comes_From_Source on L to preserve warnings for unset
10348 -- reference.
10357 -- Check for issuing warning for always False assert/check, this happens
10358 -- when assertions are turned off, in which case the pragma Assert/Check
10359 -- was transformed into:
10361 -- if False and then <condition> then ...
10363 -- and we detect this pattern
10365 if Warn_On_Assertion_Failure
10372 then
10373 declare
10376 begin
10377 -- Special handling of Asssert pragma
10381 then
10382 declare
10384 Original_Node
10385 (Expression
10388 begin
10389 -- Don't warn if original condition is explicit False,
10390 -- since obviously the failure is expected in this case.
10394 then
10397 -- Issue warning. We do not want the deletion of the
10398 -- IF/AND-THEN to take this message with it. We achieve this
10399 -- by making sure that the expanded code points to the Sloc
10400 -- of the expression, not the original pragma.
10402 else
10403 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10404 -- The source location of the expression is not usually
10405 -- the best choice here. For example, it gets located on
10406 -- the last AND keyword in a chain of boolean expressiond
10407 -- AND'ed together. It is best to put the message on the
10408 -- first character of the assertion, which is the effect
10409 -- of the First_Node call here.
10411 Error_Msg_F
10413 Expression
10418 -- Similar processing for Check pragma
10422 then
10423 -- Don't want to warn if original condition is explicit False
10425 declare
10427 Original_Node
10428 (Expression
10430 begin
10433 then
10436 -- Post warning
10438 else
10439 -- Again use Error_Msg_F rather than Error_Msg_N, see
10440 -- comment above for an explanation of why we do this.
10442 Error_Msg_F
10444 Expression
10452 -- Continue with processing of short circuit
10461 -------------------
10462 -- Resolve_Slice --
10463 -------------------
10472 begin
10475 -- Use the context type to select the prefix that yields the correct
10476 -- array type.
10478 declare
10485 begin
10493 then
10501 else
10506 else
10517 else
10527 -- If the prefix is an access to an unconstrained array, we must use
10528 -- the actual subtype of the object to perform the index checks. The
10529 -- object denoted by the prefix is implicit in the node, so we build
10530 -- an explicit representation for it in order to compute the actual
10531 -- subtype.
10536 declare
10540 begin
10551 then
10554 -- If the name is a selected component that depends on discriminants,
10555 -- build an actual subtype for it. This can happen only when the name
10556 -- itself is overloaded; otherwise the actual subtype is created when
10557 -- the selected component is analyzed.
10560 and then Full_Analysis
10562 then
10563 declare
10566 begin
10571 -- Maybe this should just be "else", instead of checking for the
10572 -- specific case of slice??? This is needed for the case where the
10573 -- prefix is an Image attribute, which gets expanded to a slice, and so
10574 -- has a constrained subtype which we want to use for the slice range
10575 -- check applied below (the range check won't get done if the
10576 -- unconstrained subtype of the 'Image is used).
10582 -- Obtain the type of the array index
10586 else
10590 -- If name was overloaded, set slice type correctly now
10594 -- Handle the generation of a range check that compares the array index
10595 -- against the discrete_range. The check is not applied to internally
10596 -- built nodes associated with the expansion of dispatch tables. Check
10597 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10598 -- the unit.
10600 if Tagged_Type_Expansion
10606 then
10609 -- The discrete_range is specified by a subtype indication. Create a
10610 -- shallow copy and inherit the type, parent and source location from
10611 -- the discrete_range. This ensures that the range check is inserted
10612 -- relative to the slice and that the runtime exception points to the
10613 -- proper construct.
10622 -- The discrete_range is a regular range. Resolve the bounds and remove
10623 -- their side effects.
10625 else
10642 -- Check bad use of type with predicates
10644 declare
10647 begin
10650 then
10652 else
10657 Bad_Predicated_Subtype_Use
10662 -- Otherwise here is where we check suspicious indexes
10673 ----------------------------
10674 -- Resolve_String_Literal --
10675 ----------------------------
10686 begin
10687 -- For a string appearing in a concatenation, defer creation of the
10688 -- string_literal_subtype until the end of the resolution of the
10689 -- concatenation, because the literal may be constant-folded away. This
10690 -- is a useful optimization for long concatenation expressions.
10692 -- If the string is an aggregate built for a single character (which
10693 -- happens in a non-static context) or a is null string to which special
10694 -- checks may apply, we build the subtype. Wide strings must also get a
10695 -- string subtype if they come from a one character aggregate. Strings
10696 -- generated by attributes might be static, but it is often hard to
10697 -- determine whether the enclosing context is static, so we generate
10698 -- subtypes for them as well, thus losing some rarer optimizations ???
10699 -- Same for strings that come from a static conversion.
10701 Need_Check :=
10710 -- If the resolving type is itself a string literal subtype, we can just
10711 -- reuse it, since there is no point in creating another.
10717 and then not Need_Check
10719 N_Attribute_Reference,
10720 N_Qualified_Expression,
10721 N_Type_Conversion)
10722 then
10725 -- Do not generate a string literal subtype for the default expression
10726 -- of a formal parameter in GNATprove mode. This is because the string
10727 -- subtype is associated with the freezing actions of the subprogram,
10728 -- however freezing is disabled in GNATprove mode and as a result the
10729 -- subtype is unavailable.
10731 elsif GNATprove_Mode
10733 then
10736 -- Otherwise we must create a string literal subtype. Note that the
10737 -- whole idea of string literal subtypes is simply to avoid the need
10738 -- for building a full fledged array subtype for each literal.
10740 else
10746 or else Need_Check
10747 then
10754 then
10760 -- The validity of a null string has been checked in the call to
10761 -- Eval_String_Literal.
10766 -- Always accept string literal with component type Any_Character, which
10767 -- occurs in error situations and in comparisons of literals, both of
10768 -- which should accept all literals.
10773 -- If the type is bit-packed, then we always transform the string
10774 -- literal into a full fledged aggregate.
10779 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10781 else
10782 -- For Standard.Wide_Wide_String, or any other type whose component
10783 -- type is Standard.Wide_Wide_Character, we know that all the
10784 -- characters in the string must be acceptable, since the parser
10785 -- accepted the characters as valid character literals.
10790 -- For the case of Standard.String, or any other type whose component
10791 -- type is Standard.Character, we must make sure that there are no
10792 -- wide characters in the string, i.e. that it is entirely composed
10793 -- of characters in range of type Character.
10795 -- If the string literal is the result of a static concatenation, the
10796 -- test has already been performed on the components, and need not be
10797 -- repeated.
10801 then
10805 -- If we are out of range, post error. This is one of the
10806 -- very few places that we place the flag in the middle of
10807 -- a token, right under the offending wide character. Not
10808 -- quite clear if this is right wrt wide character encoding
10809 -- sequences, but it's only an error message.
10811 Error_Msg
10818 -- For the case of Standard.Wide_String, or any other type whose
10819 -- component type is Standard.Wide_Character, we must make sure that
10820 -- there are no wide characters in the string, i.e. that it is
10821 -- entirely composed of characters in range of type Wide_Character.
10823 -- If the string literal is the result of a static concatenation,
10824 -- the test has already been performed on the components, and need
10825 -- not be repeated.
10829 then
10833 -- If we are out of range, post error. This is one of the
10834 -- very few places that we place the flag in the middle of
10835 -- a token, right under the offending wide character.
10837 -- This is not quite right, because characters in general
10838 -- will take more than one character position ???
10840 Error_Msg
10847 -- If the root type is not a standard character, then we will convert
10848 -- the string into an aggregate and will let the aggregate code do
10849 -- the checking. Standard Wide_Wide_Character is also OK here.
10851 else
10855 -- See if the component type of the array corresponding to the string
10856 -- has compile time known bounds. If yes we can directly check
10857 -- whether the evaluation of the string will raise constraint error.
10858 -- Otherwise we need to transform the string literal into the
10859 -- corresponding character aggregate and let the aggregate code do
10860 -- the checking. We use the same transformation if the component
10861 -- type has a static predicate, which will be applied to each
10862 -- character when the aggregate is resolved.
10866 -- Check for the case of full range, where we are definitely OK
10872 -- Here the range is not the complete base type range, so check
10874 declare
10882 begin
10885 then
10891 then
10892 Apply_Compile_Time_Constraint_Error
10894 CE_Range_Check_Failed,
10907 -- If we got here we meed to transform the string literal into the
10908 -- equivalent qualified positional array aggregate. This is rather
10909 -- heavy artillery for this situation, but it is hard work to avoid.
10911 declare
10916 begin
10917 -- Build the character literals, we give them source locations that
10918 -- correspond to the string positions, which is a bit tricky given
10919 -- the possible presence of wide character escape sequences.
10933 -- Should we have a call to Skip_Wide here ???
10935 -- ??? else
10936 -- Skip_Wide (P);
10944 Expression =>
10951 -------------------------
10952 -- Resolve_Target_Name --
10953 -------------------------
10956 begin
10960 -----------------------------
10961 -- Resolve_Type_Conversion --
10962 -----------------------------
10974 -- Set to False to suppress cases where we want to suppress the test
10975 -- for redundancy to avoid possible false positives on this warning.
10977 begin
10978 if not Conv_OK
10980 then
10984 -- If the Operand Etype is Universal_Fixed, then the conversion is
10985 -- never redundant. We need this check because by the time we have
10986 -- finished the rather complex transformation, the conversion looks
10987 -- redundant when it is not.
10992 -- If the operand is marked as Any_Fixed, then special processing is
10993 -- required. This is also a case where we suppress the test for a
10994 -- redundant conversion, since most certainly it is not redundant.
10999 -- Mixed-mode operation involving a literal. Context must be a fixed
11000 -- type which is applied to the literal subsequently.
11002 -- Multiplication and division involving two fixed type operands must
11003 -- yield a universal real because the result is computed in arbitrary
11004 -- precision.
11010 then
11016 or else
11018 then
11019 -- Return if expression is ambiguous
11024 -- If nothing else, the available fixed type is Duration
11026 else
11030 -- Resolve the real operand with largest available precision
11034 else
11040 -- If the operand is a literal (it could be a non-static and
11041 -- illegal exponentiation) check whether the use of Duration
11042 -- is potentially inaccurate.
11047 then
11048 Error_Msg_N
11051 Error_Msg_N
11058 then
11061 else
11070 -- In SPARK, a type conversion between array types should be restricted
11071 -- to types which have matching static bounds.
11073 -- Protect call to Matching_Static_Array_Bounds to avoid costly
11074 -- operation if not needed.
11081 then
11082 Check_SPARK_05_Restriction
11086 -- In formal mode, the operand of an ancestor type conversion must be an
11087 -- object (not an expression).
11095 then
11101 -- Note: we do the Eval_Type_Conversion call before applying the
11102 -- required checks for a subtype conversion. This is important, since
11103 -- both are prepared under certain circumstances to change the type
11104 -- conversion to a constraint error node, but in the case of
11105 -- Eval_Type_Conversion this may reflect an illegality in the static
11106 -- case, and we would miss the illegality (getting only a warning
11107 -- message), if we applied the type conversion checks first.
11111 -- Even when evaluation is not possible, we may be able to simplify the
11112 -- conversion or its expression. This needs to be done before applying
11113 -- checks, since otherwise the checks may use the original expression
11114 -- and defeat the simplifications. This is specifically the case for
11115 -- elimination of the floating-point Truncation attribute in
11116 -- float-to-int conversions.
11120 -- If after evaluation we still have a type conversion, then we may need
11121 -- to apply checks required for a subtype conversion.
11123 -- Skip these type conversion checks if universal fixed operands
11124 -- operands involved, since range checks are handled separately for
11125 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
11131 then
11135 -- Issue warning for conversion of simple object to its own type. We
11136 -- have to test the original nodes, since they may have been rewritten
11137 -- by various optimizations.
11141 -- Here we test for a redundant conversion if the warning mode is
11142 -- active (and was not locally reset), and we have a type conversion
11143 -- from source not appearing in a generic instance.
11145 if Test_Redundant
11148 and then not In_Instance
11149 then
11153 -- If the node is part of a larger expression, the Target_Type
11154 -- may not be the original type of the node if the context is a
11155 -- condition. Recover original type to see if conversion is needed.
11159 then
11163 -- If we have an entity name, then give the warning if the entity
11164 -- is the right type, or if it is a loop parameter covered by the
11165 -- original type (that's needed because loop parameters have an
11166 -- odd subtype coming from the bounds).
11169 and then
11171 or else
11175 -- If not an entity, then type of expression must match
11178 then
11179 -- One more check, do not give warning if the analyzed conversion
11180 -- has an expression with non-static bounds, and the bounds of the
11181 -- target are static. This avoids junk warnings in cases where the
11182 -- conversion is necessary to establish staticness, for example in
11183 -- a case statement.
11187 then
11190 -- Finally, if this type conversion occurs in a context requiring
11191 -- a prefix, and the expression is a qualified expression then the
11192 -- type conversion is not redundant, since a qualified expression
11193 -- is not a prefix, whereas a type conversion is. For example, "X
11194 -- := T'(Funx(...)).Y;" is illegal because a selected component
11195 -- requires a prefix, but a type conversion makes it legal: "X :=
11196 -- T(T'(Funx(...))).Y;"
11198 -- In Ada 2012, a qualified expression is a name, so this idiom is
11199 -- no longer needed, but we still suppress the warning because it
11200 -- seems unfriendly for warnings to pop up when you switch to the
11201 -- newer language version.
11205 N_Indexed_Component,
11206 N_Selected_Component,
11207 N_Slice,
11208 N_Explicit_Dereference)
11209 then
11212 -- Never warn on conversion to Long_Long_Integer'Base since
11213 -- that is most likely an artifact of the extended overflow
11214 -- checking and comes from complex expanded code.
11219 -- Here we give the redundant conversion warning. If it is an
11220 -- entity, give the name of the entity in the message. If not,
11221 -- just mention the expression.
11223 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11225 else
11228 Error_Msg_NE -- CODEFIX
11231 else
11232 Error_Msg_NE
11240 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11241 -- No need to perform any interface conversion if the type of the
11242 -- expression coincides with the target type.
11245 and then Expander_Active
11247 then
11248 declare
11252 begin
11253 -- If the type of the operand is a limited view, use nonlimited
11254 -- view when available. If it is a class-wide type, recover the
11255 -- class-wide type of the nonlimited view.
11259 then
11275 -- Conversion from interface type
11279 -- Ada 2005 (AI-217): Handle entities from limited views
11283 Error_Msg_NE -- CODEFIX
11286 Error_Msg_N
11288 N);
11291 and then not
11294 then
11296 Error_Msg_NE -- CODEFIX
11299 Error_Msg_N
11301 N);
11303 else
11307 -- Conversion to interface type
11311 -- Handle subtypes
11318 or else Interface_Present_In_Ancestor
11321 then
11323 else
11326 Error_Msg_N
11334 -- Ada 2012: once the type conversion is resolved, check whether the
11335 -- operand statisfies the static predicate of the target type.
11341 -- If at this stage we have a real to integer conversion, make sure that
11342 -- the Do_Range_Check flag is set, because such conversions in general
11343 -- need a range check. We only need this if expansion is off.
11344 -- In GNATprove mode, we only do that when converting from fixed-point
11345 -- (as floating-point to integer conversions are now handled in
11346 -- GNATprove mode).
11349 and then not Expander_Active
11354 then
11358 -- Generating C code a type conversion of an access to constrained
11359 -- array type to access to unconstrained array type involves building
11360 -- a fat pointer which in general cannot be generated on the fly. We
11361 -- remove side effects in order to store the result of the conversion
11362 -- into a temporary.
11364 if Modify_Tree_For_C
11371 then
11376 ----------------------
11377 -- Resolve_Unary_Op --
11378 ----------------------
11387 begin
11390 Check_SPARK_05_Restriction
11394 -- Deal with intrinsic unary operators
11400 then
11405 -- Deal with universal cases
11408 or else
11410 then
11417 -- Generate warning for expressions like abs (x mod 2)
11419 if Warn_On_Redundant_Constructs
11421 then
11425 Error_Msg_N -- CODEFIX
11430 -- Deal with reference generation
11437 -- Set overflow checking bit. Much cleverer code needed here eventually
11438 -- and perhaps the Resolve routines should be separated for the various
11439 -- arithmetic operations, since they will need different processing ???
11447 -- Generate warning for expressions like -5 mod 3 for integers. No need
11448 -- to worry in the floating-point case, since parens do not affect the
11449 -- result so there is no point in giving in a warning.
11451 declare
11460 begin
11461 if Warn_On_Questionable_Missing_Parens
11465 then
11468 -- We are looking for cases where the right operand is not
11469 -- parenthesized, and is a binary operator, multiply, divide, or
11470 -- mod. These are the cases where the grouping can affect results.
11474 then
11475 -- For mod, we always give the warning, since the value is
11476 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11477 -- -(5 mod 315)). But for the other cases, the only concern is
11478 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11479 -- overflows, but (-2) * 64 does not). So we try to give the
11480 -- message only when overflow is possible.
11484 then
11489 else
11495 else
11499 -- Note that the test below is deliberately excluding the
11500 -- largest negative number, since that is a potentially
11501 -- troublesome case (e.g. -2 * x, where the result is the
11502 -- largest negative integer has an overflow with 2 * x).
11509 -- For the multiplication case, the only case we have to worry
11510 -- about is when (-a)*b is exactly the largest negative number
11511 -- so that -(a*b) can cause overflow. This can only happen if
11512 -- a is a power of 2, and more generally if any operand is a
11513 -- constant that is not a power of 2, then the parentheses
11514 -- cannot affect whether overflow occurs. We only bother to
11515 -- test the left most operand
11517 -- Loop looking at left operands for one that has known value
11524 -- Operand value of 0 or 1 skips warning
11529 -- Otherwise check power of 2, if power of 2, warn, if
11530 -- anything else, skip warning.
11532 else
11536 else
11545 -- Keep looking at left operands
11550 -- For rem or "/" we can only have a problematic situation
11551 -- if the divisor has a value of minus one or one. Otherwise
11552 -- overflow is impossible (divisor > 1) or we have a case of
11553 -- division by zero in any case.
11558 then
11562 -- If we fall through warning should be issued
11564 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11566 Error_Msg_N
11573 ----------------------------------
11574 -- Resolve_Unchecked_Expression --
11575 ----------------------------------
11577 procedure Resolve_Unchecked_Expression
11580 is
11581 begin
11586 ---------------------------------------
11587 -- Resolve_Unchecked_Type_Conversion --
11588 ---------------------------------------
11590 procedure Resolve_Unchecked_Type_Conversion
11593 is
11599 begin
11600 -- Resolve operand using its own type
11604 -- In an inlined context, the unchecked conversion may be applied
11605 -- to a literal, in which case its type is the type of the context.
11606 -- (In other contexts conversions cannot apply to literals).
11608 if In_Inlined_Body
11612 then
11620 ------------------------------
11621 -- Rewrite_Operator_As_Call --
11622 ------------------------------
11629 begin
11636 New_N :=
11647 ------------------------------
11648 -- Rewrite_Renamed_Operator --
11649 ------------------------------
11651 procedure Rewrite_Renamed_Operator
11655 is
11660 begin
11661 -- Do not perform this transformation within a pre/postcondition,
11662 -- because the expression will be reanalyzed, and the transformation
11663 -- might affect the visibility of the operator, e.g. in an instance.
11664 -- Note that fully analyzed and expanded pre/postconditions appear as
11665 -- pragma Check equivalents.
11671 -- Likewise when an expression function is being preanalyzed, since the
11672 -- expression will be reanalyzed as part of the generated body.
11675 declare
11677 begin
11680 N_Expression_Function
11681 then
11687 -- Rewrite the operator node using the real operator, not its renaming.
11688 -- Exclude user-defined intrinsic operations of the same name, which are
11689 -- treated separately and rewritten as calls.
11698 -- Indicate that both the original entity and its renaming are
11699 -- referenced at this point.
11710 -- If the context type is private, add the appropriate conversions so
11711 -- that the operator is applied to the full view. This is done in the
11712 -- routines that resolve intrinsic operators.
11716 when N_Op_Add
11717 | N_Op_Divide
11718 | N_Op_Expon
11719 | N_Op_Mod
11720 | N_Op_Multiply
11721 | N_Op_Rem
11722 | N_Op_Subtract
11723 =>
11726 when N_Op_Abs
11727 | N_Op_Minus
11728 | N_Op_Plus
11729 =>
11739 -- Operator renames a user-defined operator of the same name. Use the
11740 -- original operator in the node, which is the one Gigi knows about.
11747 -----------------------
11748 -- Set_Slice_Subtype --
11749 -----------------------
11751 -- Build an implicit subtype declaration to represent the type delivered by
11752 -- the slice. This is an abbreviated version of an array subtype. We define
11753 -- an index subtype for the slice, using either the subtype name or the
11754 -- discrete range of the slice. To be consistent with index usage elsewhere
11755 -- we create a list header to hold the single index. This list is not
11756 -- otherwise attached to the syntax tree.
11767 begin
11773 else
11774 -- We force the evaluation of a range. This is definitely needed in
11775 -- the renamed case, and seems safer to do unconditionally. Note in
11776 -- any case that since we will create and insert an Itype referring
11777 -- to this range, we must make sure any side effect removal actions
11778 -- are inserted before the Itype definition.
11784 -- If the discrete range is given by a subtype indication, the
11785 -- type of the slice is the base of the subtype mark.
11788 declare
11790 begin
11799 -- Take a new copy of Drange (where bounds have been rewritten to
11800 -- reference side-effect-free names). Using a separate tree ensures
11801 -- that further expansion (e.g. while rewriting a slice assignment
11802 -- into a FOR loop) does not attempt to remove side effects on the
11803 -- bounds again (which would cause the bounds in the index subtype
11804 -- definition to refer to temporaries before they are defined) (the
11805 -- reason is that some names are considered side effect free here
11806 -- for the subtype, but not in the context of a loop iteration
11807 -- scheme).
11828 -- The Etype of the existing Slice node is reset to this slice subtype.
11829 -- Its bounds are obtained from its first index.
11833 -- For bit-packed slice subtypes, freeze immediately (except in the case
11834 -- of being in a "spec expression" where we never freeze when we first
11835 -- see the expression).
11840 -- For all other cases insert an itype reference in the slice's actions
11841 -- so that the itype is frozen at the proper place in the tree (i.e. at
11842 -- the point where actions for the slice are analyzed). Note that this
11843 -- is different from freezing the itype immediately, which might be
11844 -- premature (e.g. if the slice is within a transient scope). This needs
11845 -- to be done only if expansion is enabled.
11852 --------------------------------
11853 -- Set_String_Literal_Subtype --
11854 --------------------------------
11862 begin
11874 -- The low bound is set from the low bound of the corresponding index
11875 -- type. Note that we do not store the high bound in the string literal
11876 -- subtype, but it can be deduced if necessary from the length and the
11877 -- low bound.
11882 -- If the lower bound is not static we create a range for the string
11883 -- literal, using the index type and the known length of the literal.
11884 -- The index type is not necessarily Positive, so the upper bound is
11885 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11887 else
11888 declare
11894 Prefix =>
11898 Left_Opnd =>
11901 Prefix =>
11903 Expressions =>
11905 Right_Opnd =>
11914 begin
11916 Set_String_Literal_Low_Bound
11919 else
11920 -- If the index type is an enumeration type, build bounds
11921 -- expression with attributes.
11923 Set_String_Literal_Low_Bound
11927 Prefix =>
11934 -- Build bona fide subtype for the string, and wrap it in an
11935 -- unchecked conversion, because the back end expects the
11936 -- String_Literal_Subtype to have a static lower bound.
11938 Index_Subtype :=
11945 -- In this context, the Index_Type may already have a constraint,
11946 -- so use common base type on string subtype. The base type may
11947 -- be used when generating attributes of the string, for example
11948 -- in the context of a slice assignment.
11973 ------------------------------
11974 -- Simplify_Type_Conversion --
11975 ------------------------------
11978 begin
11980 declare
11985 begin
11986 -- Special processing if the conversion is the expression of a
11987 -- Rounding or Truncation attribute reference. In this case we
11988 -- replace:
11990 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11992 -- by
11994 -- ityp (x)
11996 -- with the Float_Truncate flag set to False or True respectively,
11997 -- which is more efficient.
12000 and then
12006 Name_Truncation)
12007 then
12008 declare
12011 begin
12021 -----------------------------
12022 -- Unique_Fixed_Point_Type --
12023 -----------------------------
12027 -- Give error messages for true ambiguity. Messages are posted on node
12028 -- N, and entities T1, T2 are the possible interpretations.
12030 -----------------------
12031 -- Fixed_Point_Error --
12032 -----------------------
12035 begin
12041 -- Local variables
12049 -- Start of processing for Unique_Fixed_Point_Type
12051 begin
12052 -- The operations on Duration are visible, so Duration is always a
12053 -- possible interpretation.
12057 -- Look for fixed-point types in enclosing scopes
12066 then
12070 else
12081 -- Look for visible fixed type declarations in the context
12092 then
12096 else
12111 else
12112 -- When the context is a type conversion, issue the warning on the
12113 -- expression of the conversion because it is the actual operation.
12117 else
12121 Error_Msg_NE
12128 ----------------------
12129 -- Valid_Conversion --
12130 ----------------------
12132 function Valid_Conversion
12137 is
12142 function Conversion_Check
12145 -- Little routine to post Msg if Valid is False, returns Valid value
12148 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
12150 procedure Conversion_Error_NE
12154 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
12157 -- Return True if expression is within an instance but is not in one of
12158 -- the actuals of the instantiation. Type conversions within an instance
12159 -- are not rechecked because type visbility may lead to spurious errors,
12160 -- but conversions in an actual for a formal object must be checked.
12162 function Valid_Tagged_Conversion
12165 -- Specifically test for validity of tagged conversions
12168 -- Check index and component conformance, and accessibility levels if
12169 -- the component types are anonymous access types (Ada 2005).
12171 ----------------------
12172 -- Conversion_Check --
12173 ----------------------
12175 function Conversion_Check
12178 is
12179 begin
12180 if not Valid
12182 -- A generic unit has already been analyzed and we have verified
12183 -- that a particular conversion is OK in that context. Since the
12184 -- instance is reanalyzed without relying on the relationships
12185 -- established during the analysis of the generic, it is possible
12186 -- to end up with inconsistent views of private types. Do not emit
12187 -- the error message in such cases. The rest of the machinery in
12188 -- Valid_Conversion still ensures the proper compatibility of
12189 -- target and operand types.
12191 and then not In_Instance_Code
12192 then
12199 ------------------------
12200 -- Conversion_Error_N --
12201 ------------------------
12204 begin
12210 -------------------------
12211 -- Conversion_Error_NE --
12212 -------------------------
12214 procedure Conversion_Error_NE
12218 is
12219 begin
12225 ----------------------
12226 -- In_Instance_Code --
12227 ----------------------
12232 begin
12236 else
12240 -- The expression is part of an actual object if it appears in
12241 -- the generated object declaration in the instance.
12245 then
12248 else
12249 exit when
12258 -- Otherwise the expression appears within the instantiated unit
12264 ----------------------------
12265 -- Valid_Array_Conversion --
12266 ----------------------------
12283 begin
12284 -- Error if wrong number of dimensions
12286 if
12288 then
12289 Conversion_Error_N
12293 -- Number of dimensions matches
12295 else
12296 -- Loop through indexes of the two arrays
12304 -- Error if index types are incompatible
12310 then
12311 Conversion_Error_N
12313 Operand);
12321 -- If component types have same base type, all set
12326 -- Here if base types of components are not the same. The only
12327 -- time this is allowed is if we have anonymous access types.
12329 -- The conversion of arrays of anonymous access types can lead
12330 -- to dangling pointers. AI-392 formalizes the accessibility
12331 -- checks that must be applied to such conversions to prevent
12332 -- out-of-scope references.
12334 elsif Ekind_In
12336 E_Anonymous_Access_Subprogram_Type)
12338 and then
12340 then
12343 then
12346 Conversion_Error_N
12356 -- Conversion not allowed because of accessibility levels
12358 else
12359 Conversion_Error_N
12365 else
12369 -- All other cases where component base types do not match
12371 else
12372 Conversion_Error_N
12374 Operand);
12378 -- Check that component subtypes statically match. For numeric
12379 -- types this means that both must be either constrained or
12380 -- unconstrained. For enumeration types the bounds must match.
12381 -- All of this is checked in Subtypes_Statically_Match.
12383 if not Subtypes_Statically_Match
12385 then
12386 Conversion_Error_N
12395 -----------------------------
12396 -- Valid_Tagged_Conversion --
12397 -----------------------------
12399 function Valid_Tagged_Conversion
12402 is
12403 begin
12404 -- Upward conversions are allowed (RM 4.6(22))
12408 then
12411 -- Downward conversion are allowed if the operand is class-wide
12412 -- (RM 4.6(23)).
12416 then
12421 then
12422 return
12426 -- Ada 2005 (AI-251): The conversion to/from interface types is
12427 -- always valid. The types involved may be class-wide (sub)types.
12431 then
12434 -- If the operand is a class-wide type obtained through a limited_
12435 -- with clause, and the context includes the nonlimited view, use
12436 -- it to determine whether the conversion is legal.
12442 then
12447 then
12450 else
12451 Conversion_Error_NE
12458 -- Start of processing for Valid_Conversion
12460 begin
12464 declare
12472 begin
12473 -- Remove procedure calls, which syntactically cannot appear in
12474 -- this context, but which cannot be removed by type checking,
12475 -- because the context does not impose a type.
12477 -- The node may be labelled overloaded, but still contain only one
12478 -- interpretation because others were discarded earlier. If this
12479 -- is the case, retain the single interpretation if legal.
12487 then
12488 -- More than one candidate interpretation is available
12496 -- When compiling for a system where Address is of a visible
12497 -- integer type, spurious ambiguities can be produced when
12498 -- arithmetic operations have a literal operand and return
12499 -- System.Address or a descendant of it. These ambiguities
12500 -- are usually resolved by the context, but for conversions
12501 -- there is no context type and the removal of the spurious
12502 -- operations must be done explicitly here.
12504 if not Address_Is_Private
12506 then
12531 Conversion_Error_N
12534 -- If the interpretation involves a standard operator, use
12535 -- the location of the type, which may be user-defined.
12539 else
12543 Conversion_Error_N -- CODEFIX
12548 else
12552 Conversion_Error_N -- CODEFIX
12564 -- Deal with conversion of integer type to address if the pragma
12565 -- Allow_Integer_Address is in effect. We convert the conversion to
12566 -- an unchecked conversion in this case and we are all done.
12574 -- If we are within a child unit, check whether the type of the
12575 -- expression has an ancestor in a parent unit, in which case it
12576 -- belongs to its derivation class even if the ancestor is private.
12577 -- See RM 7.3.1 (5.2/3).
12581 -- Numeric types
12585 -- A universal fixed expression can be converted to any numeric type
12590 -- Also no need to check when in an instance or inlined body, because
12591 -- the legality has been established when the template was analyzed.
12592 -- Furthermore, numeric conversions may occur where only a private
12593 -- view of the operand type is visible at the instantiation point.
12594 -- This results in a spurious error if we check that the operand type
12595 -- is a numeric type.
12597 -- Note: in a previous version of this unit, the following tests were
12598 -- applied only for generated code (Comes_From_Source set to False),
12599 -- but in fact the test is required for source code as well, since
12600 -- this situation can arise in source code.
12605 -- Otherwise we need the conversion check
12607 else
12608 return Conversion_Check
12610 or else
12616 -- Array types
12622 then
12623 Conversion_Error_N
12627 else
12631 -- Ada 2005 (AI-251): Internally generated conversions of access to
12632 -- interface types added to force the displacement of the pointer to
12633 -- reference the corresponding dispatch table.
12638 then
12641 -- Ada 2005 (AI-251): Anonymous access types where target references an
12642 -- interface type.
12646 E_Anonymous_Access_Type)
12648 then
12649 -- Check the static accessibility rule of 4.6(17). Note that the
12650 -- check is not enforced when within an instance body, since the
12651 -- RM requires such cases to be caught at run time.
12653 -- If the operand is a rewriting of an allocator no check is needed
12654 -- because there are no accessibility issues.
12662 then
12663 -- In an instance, this is a run-time check, but one we know
12664 -- will fail, so generate an appropriate warning. The raise
12665 -- will be generated by Expand_N_Type_Conversion.
12669 Conversion_Error_N
12671 Operand);
12674 else
12675 Conversion_Error_N
12677 Operand);
12681 -- Special accessibility checks are needed in the case of access
12682 -- discriminants declared for a limited type.
12686 then
12687 -- When the operand is a selected access discriminant the check
12688 -- needs to be made against the level of the object denoted by
12689 -- the prefix of the selected name (Object_Access_Level handles
12690 -- checking the prefix of the operand for this case).
12695 then
12696 -- In an instance, this is a run-time check, but one we know
12697 -- will fail, so generate an appropriate warning. The raise
12698 -- will be generated by Expand_N_Type_Conversion.
12702 Conversion_Error_N
12707 -- Real error if not in instance body
12709 else
12710 Conversion_Error_N
12717 -- The case of a reference to an access discriminant from
12718 -- within a limited type declaration (which will appear as
12719 -- a discriminal) is always illegal because the level of the
12720 -- discriminant is considered to be deeper than any (nameable)
12721 -- access type.
12725 and then
12728 then
12729 Conversion_Error_N
12731 Operand);
12739 -- General and anonymous access types
12742 E_Anonymous_Access_Type)
12743 and then
12744 Conversion_Check
12746 and then not
12748 E_Access_Protected_Subprogram_Type),
12750 then
12753 then
12754 Conversion_Error_N
12759 -- Check the static accessibility rule of 4.6(17). Note that the
12760 -- check is not enforced when within an instance body, since the RM
12761 -- requires such cases to be caught at run time.
12766 N_Object_Declaration
12767 then
12768 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12769 -- conversions from an anonymous access type to a named general
12770 -- access type. Such conversions are not allowed in the case of
12771 -- access parameters and stand-alone objects of an anonymous
12772 -- access type. The implicit conversion case is recognized by
12773 -- testing that Comes_From_Source is False and that it's been
12774 -- rewritten. The Comes_From_Source test isn't sufficient because
12775 -- nodes in inlined calls to predefined library routines can have
12776 -- Comes_From_Source set to False. (Is there a better way to test
12777 -- for implicit conversions???)
12784 then
12787 -- Implicit conversions aren't allowed for objects of an
12788 -- anonymous access type, since such objects have nonstatic
12789 -- levels in Ada 2012.
12792 N_Object_Declaration
12793 then
12794 Conversion_Error_N
12799 -- Implicit conversions aren't allowed for anonymous access
12800 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12801 -- is done to exclude anonymous access results.
12805 N_Function_Specification,
12806 N_Procedure_Specification)
12807 then
12808 Conversion_Error_N
12813 -- This is a case where there's an enclosing object whose
12814 -- to which the "statically deeper than" relationship does
12815 -- not apply (such as an access discriminant selected from
12816 -- a dereference of an access parameter).
12820 then
12821 Conversion_Error_N
12826 -- In other cases, the level of the operand's type must be
12827 -- statically less deep than that of the target type, else
12828 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12832 then
12833 Conversion_Error_N
12842 then
12843 -- In an instance, this is a run-time check, but one we know
12844 -- will fail, so generate an appropriate warning. The raise
12845 -- will be generated by Expand_N_Type_Conversion.
12849 Conversion_Error_N
12851 Operand);
12854 -- If not in an instance body, this is a real error
12856 else
12857 -- Avoid generation of spurious error message
12860 Conversion_Error_N
12862 Operand);
12868 -- Special accessibility checks are needed in the case of access
12869 -- discriminants declared for a limited type.
12873 then
12874 -- When the operand is a selected access discriminant the check
12875 -- needs to be made against the level of the object denoted by
12876 -- the prefix of the selected name (Object_Access_Level handles
12877 -- checking the prefix of the operand for this case).
12882 then
12883 -- In an instance, this is a run-time check, but one we know
12884 -- will fail, so generate an appropriate warning. The raise
12885 -- will be generated by Expand_N_Type_Conversion.
12889 Conversion_Error_N
12894 -- If not in an instance body, this is a real error
12896 else
12897 Conversion_Error_N
12904 -- The case of a reference to an access discriminant from
12905 -- within a limited type declaration (which will appear as
12906 -- a discriminal) is always illegal because the level of the
12907 -- discriminant is considered to be deeper than any (nameable)
12908 -- access type.
12911 and then
12914 then
12915 Conversion_Error_N
12917 Operand);
12923 -- In the presence of limited_with clauses we have to use nonlimited
12924 -- views, if available.
12928 -- Helper function to handle limited views
12930 --------------------------
12931 -- Full_Designated_Type --
12932 --------------------------
12937 begin
12938 -- Handle the limited view of a type
12942 then
12944 else
12949 -- Local Declarations
12957 -- Start of processing for Check_Limited
12959 begin
12963 else
12965 Conversion_Error_NE
12970 -- Ada 2005 AI-384: legality rule is symmetric in both
12971 -- designated types. The conversion is legal (with possible
12972 -- constraint check) if either designated type is
12973 -- unconstrained.
12976 or else
12978 and then
12981 then
12982 -- Special case, if Value_Size has been used to make the
12983 -- sizes different, the conversion is not allowed even
12984 -- though the subtypes statically match.
12989 then
12990 Conversion_Error_NE
12993 Conversion_Error_NE
12998 -- Normal case where conversion is allowed
13000 else
13004 else
13005 Error_Msg_NE
13013 -- Access to subprogram types. If the operand is an access parameter,
13014 -- the type has a deeper accessibility that any master, and cannot be
13015 -- assigned. We must make an exception if the conversion is part of an
13016 -- assignment and the target is the return object of an extended return
13017 -- statement, because in that case the accessibility check takes place
13018 -- after the return.
13022 -- Note: this test of Opnd_Type is there to prevent entering this
13023 -- branch in the case of a remote access to subprogram type, which
13024 -- is internally represented as an E_Record_Type.
13027 then
13031 and then
13035 then
13036 Conversion_Error_N
13038 Operand);
13039 Conversion_Error_N
13042 Operand);
13044 Error_Msg_NE
13049 -- Check that the designated types are subtype conformant
13055 -- Check the static accessibility rule of 4.6(20)
13059 then
13060 Conversion_Error_N
13062 Operand);
13064 -- Check that if the operand type is declared in a generic body,
13065 -- then the target type must be declared within that same body
13066 -- (enforces last sentence of 4.6(20)).
13069 declare
13075 begin
13082 Conversion_Error_N
13091 -- Remote access to subprogram types
13095 then
13096 -- It is valid to convert from one RAS type to another provided
13097 -- that their specification statically match.
13099 -- Note: at this point, remote access to subprogram types have been
13100 -- expanded to their E_Record_Type representation, and we need to
13101 -- go back to the original access type definition using the
13102 -- Corresponding_Remote_Type attribute in order to check that the
13103 -- designated profiles match.
13108 Check_Subtype_Conformant
13111 Old_Id =>
13113 Err_Loc =>
13114 N);
13117 -- If it was legal in the generic, it's legal in the instance
13122 -- If both are tagged types, check legality of view conversions
13125 and then
13127 then
13130 -- Types derived from the same root type are convertible
13135 -- In an instance or an inlined body, there may be inconsistent views of
13136 -- the same type, or of types derived from a common root.
13139 and then
13142 then
13145 -- Special check for common access type error case
13149 then
13151 Conversion_Error_NE -- CODEFIX
13155 -- Here we have a real conversion error
13157 else
13158 -- Check for missing regular with_clause when only a limited view of
13159 -- target is available.
13162 Conversion_Error_NE
13165 Conversion_Error_NE
13170 and then In_Package_Body
13171 then
13172 Conversion_Error_NE
13174 Conversion_Error_NE
13178 else
13179 Conversion_Error_NE