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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. However an implicit call to
6071 -- an expression function may appear when it is part of a default
6072 -- expression in a call to an initialiation procedure, and must be
6073 -- frozen now, even if the body is inserted at a later point.
6076 and then not In_Spec_Expression
6078 and then
6081 then
6084 -- Force freeze of expression function in call
6093 -- For a predefined operator, the type of the result is the type imposed
6094 -- by context, except for a predefined operation on universal fixed.
6095 -- Otherwise the type of the call is the type returned by the subprogram
6096 -- being called.
6103 -- If the subprogram returns an array type, and the context requires the
6104 -- component type of that array type, the node is really an indexing of
6105 -- the parameterless call. Resolve as such. A pathological case occurs
6106 -- when the type of the component is an access to the array type. In
6107 -- this case the call is truly ambiguous. If the call is to an intrinsic
6108 -- subprogram, it can't be an indexed component. This check is necessary
6109 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6110 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6111 -- pointers to the same array), the compiler gets confused and does an
6112 -- infinite recursion.
6115 and then
6118 or else
6121 and then
6124 then
6125 declare
6130 begin
6131 -- If this is a parameterless call there is no ambiguity and the
6132 -- call has the type of the function.
6141 -- Annotate the tree by creating a call marker in case the
6142 -- original call is transformed by expansion. The call marker
6143 -- is automatically saved for later examination by the ABE
6144 -- Processing phase.
6151 then
6152 Error_Msg_N
6154 else
6157 -- The called entity may be an explicit dereference, in which
6158 -- case there is no entity to set.
6166 or else
6168 and then
6170 then
6173 -- Indexed call to a parameterless function
6175 Index_Node :=
6177 Prefix =>
6180 else
6181 -- An Ada 2005 prefixed call to a primitive operation
6182 -- whose first parameter is the prefix. This prefix was
6183 -- prepended to the parameter list, which is actually a
6184 -- list of indexes. Remove the prefix in order to build
6185 -- the proper indexed component.
6187 Index_Node :=
6189 Prefix =>
6192 Parameter_Associations =>
6193 New_List
6198 -- Preserve the parenthesis count of the node
6202 -- Since we are correcting a node classification error made
6203 -- by the parser, we call Replace rather than Rewrite.
6215 -- Annotate the tree by creating a call marker in case
6216 -- the original call is transformed by expansion. The call
6217 -- marker is automatically saved for later examination by
6218 -- the ABE Processing phase.
6227 else
6228 -- If the called function is not declared in the main unit and it
6229 -- returns the limited view of type then use the available view (as
6230 -- is done in Try_Object_Operation) to prevent back-end confusion;
6231 -- for the function entity itself. The call must appear in a context
6232 -- where the nonlimited view is available. If the function entity is
6233 -- in the extended main unit then no action is needed, because the
6234 -- back end handles this case. In either case the type of the call
6235 -- is the nonlimited view.
6239 then
6246 else
6251 -- In the case where the call is to an overloaded subprogram, Analyze
6252 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6253 -- such a case Normalize_Actuals needs to be called once more to order
6254 -- the actuals correctly. Otherwise the call will have the ordering
6255 -- given by the last overloaded subprogram whether this is the correct
6256 -- one being called or not.
6263 -- In any case, call is fully resolved now. Reset Overload flag, to
6264 -- prevent subsequent overload resolution if node is analyzed again
6269 -- A Ghost entity must appear in a specific context
6275 -- If we are calling the current subprogram from immediately within its
6276 -- body, then that is the case where we can sometimes detect cases of
6277 -- infinite recursion statically. Do not try this in case restriction
6278 -- No_Recursion is in effect anyway, and do it only for source calls.
6283 -- Check violation of SPARK_05 restriction which does not permit
6284 -- a subprogram body to contain a call to the subprogram directly.
6288 then
6289 Check_SPARK_05_Restriction
6293 -- Issue warning for possible infinite recursion in the absence
6294 -- of the No_Recursion restriction.
6299 then
6300 -- Here we detected and flagged an infinite recursion, so we do
6301 -- not need to test the case below for further warnings. Also we
6302 -- are all done if we now have a raise SE node.
6308 -- If call is to immediately containing subprogram, then check for
6309 -- the case of a possible run-time detectable infinite recursion.
6311 else
6315 -- Although in general case, recursion is not statically
6316 -- checkable, the case of calling an immediately containing
6317 -- subprogram is easy to catch.
6321 -- If the recursive call is to a parameterless subprogram,
6322 -- then even if we can't statically detect infinite
6323 -- recursion, this is pretty suspicious, and we output a
6324 -- warning. Furthermore, we will try later to detect some
6325 -- cases here at run time by expanding checking code (see
6326 -- Detect_Infinite_Recursion in package Exp_Ch6).
6328 -- If the recursive call is within a handler, do not emit a
6329 -- warning, because this is a common idiom: loop until input
6330 -- is correct, catch illegal input in handler and restart.
6336 then
6337 -- For the case of a procedure call. We give the message
6338 -- only if the call is the first statement in a sequence
6339 -- of statements, or if all previous statements are
6340 -- simple assignments. This is simply a heuristic to
6341 -- decrease false positives, without losing too many good
6342 -- warnings. The idea is that these previous statements
6343 -- may affect global variables the procedure depends on.
6344 -- We also exclude raise statements, that may arise from
6345 -- constraint checks and are probably unrelated to the
6346 -- intended control flow.
6350 then
6351 declare
6353 begin
6357 N_Raise_Constraint_Error)
6358 then
6367 -- Do not give warning if we are in a conditional context
6369 declare
6371 begin
6377 then
6382 -- Here warning is to be issued
6398 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6402 -- If subprogram name is a predefined operator, it was given in
6403 -- functional notation. Replace call node with operator node, so
6404 -- that actuals can be resolved appropriately.
6412 then
6418 -- Create a transient scope if the resulting type requires it
6420 -- There are several notable exceptions:
6422 -- a) In init procs, the transient scope overhead is not needed, and is
6423 -- even incorrect when the call is a nested initialization call for a
6424 -- component whose expansion may generate adjust calls. However, if the
6425 -- call is some other procedure call within an initialization procedure
6426 -- (for example a call to Create_Task in the init_proc of the task
6427 -- run-time record) a transient scope must be created around this call.
6429 -- b) Enumeration literal pseudo-calls need no transient scope
6431 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6432 -- functions) do not use the secondary stack even though the return
6433 -- type may be unconstrained.
6435 -- d) Calls to a build-in-place function, since such functions may
6436 -- allocate their result directly in a target object, and cases where
6437 -- the result does get allocated in the secondary stack are checked for
6438 -- within the specialized Exp_Ch6 procedures for expanding those
6439 -- build-in-place calls.
6441 -- e) Calls to inlinable expression functions do not use the secondary
6442 -- stack (since the call will be replaced by its returned object).
6444 -- f) If the subprogram is marked Inline_Always, then even if it returns
6445 -- an unconstrained type the call does not require use of the secondary
6446 -- stack. However, inlining will only take place if the body to inline
6447 -- is already present. It may not be available if e.g. the subprogram is
6448 -- declared in a child instance.
6454 then
6461 then
6464 elsif Expander_Active
6467 then
6470 -- If the call appears within the bounds of a loop, it will be
6471 -- rewritten and reanalyzed, nothing left to do here.
6478 -- A protected function cannot be called within the definition of the
6479 -- enclosing protected type, unless it is part of a pre/postcondition
6480 -- on another protected operation. This may appear in the entry wrapper
6481 -- created for an entry with preconditions.
6486 and then not In_Spec_Expression
6488 then
6489 Error_Msg_NE
6493 -- Propagate interpretation to actuals, and add default expressions
6494 -- where needed.
6499 -- Overloaded literals are rewritten as function calls, for purpose of
6500 -- resolution. After resolution, we can replace the call with the
6501 -- literal itself.
6507 -- Avoid validation, since it is a static function call
6513 -- If the subprogram is not global, then kill all saved values and
6514 -- checks. This is a bit conservative, since in many cases we could do
6515 -- better, but it is not worth the effort. Similarly, we kill constant
6516 -- values. However we do not need to do this for internal entities
6517 -- (unless they are inherited user-defined subprograms), since they
6518 -- are not in the business of molesting local values.
6520 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6521 -- kill all checks and values for calls to global subprograms. This
6522 -- takes care of the case where an access to a local subprogram is
6523 -- taken, and could be passed directly or indirectly and then called
6524 -- from almost any context.
6526 -- Note: we do not do this step till after resolving the actuals. That
6527 -- way we still take advantage of the current value information while
6528 -- scanning the actuals.
6530 -- We suppress killing values if we are processing the nodes associated
6531 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6532 -- type kills all the values as part of analyzing the code that
6533 -- initializes the dispatch tables.
6537 or else Suppress_Value_Tracking_On_Call
6542 then
6543 Kill_Current_Values;
6546 -- If we are warning about unread OUT parameters, this is the place to
6547 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6548 -- after the above call to Kill_Current_Values (since that call clears
6549 -- the Last_Assignment field of all local variables).
6554 then
6555 declare
6559 begin
6569 then
6579 -- If the subprogram is a primitive operation, check whether or not
6580 -- it is a correct dispatching call.
6584 then
6589 and then not In_Instance
6590 then
6594 -- If this is a dispatching call, generate the appropriate reference,
6595 -- for better source navigation in GPS.
6599 then
6602 -- Normal case, not a dispatching call: generate a call reference
6604 else
6612 -- Check for violation of restriction No_Specific_Termination_Handlers
6613 -- and warn on a potentially blocking call to Abort_Task.
6617 or else
6619 then
6626 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6627 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6628 -- need to check the second argument to determine whether it is an
6629 -- absolute or relative timing event.
6634 then
6638 -- Issue an error for a call to an eliminated subprogram. This routine
6639 -- will not perform the check if the call appears within a default
6640 -- expression.
6644 -- In formal mode, the primitive operations of a tagged type or type
6645 -- extension do not include functions that return the tagged type.
6651 then
6655 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6656 -- class-wide and the call dispatches on result in a context that does
6657 -- not provide a tag, the call raises Program_Error.
6660 and then In_Instance
6665 then
6666 -- Verify that none of the formals are controlling
6668 declare
6672 begin
6694 -- Check for calling a function with OUT or IN OUT parameter when the
6695 -- calling context (us right now) is not Ada 2012, so does not allow
6696 -- OUT or IN OUT parameters in function calls. Functions declared in
6697 -- a predefined unit are OK, as they may be called indirectly from a
6698 -- user-declared instantiation.
6704 then
6709 -- Check the dimensions of the actuals in the call. For function calls,
6710 -- propagate the dimensions from the returned type to N.
6714 -- All done, evaluate call and deal with elaboration issues
6722 -- Annotate the tree by creating a call marker in case the original call
6723 -- is transformed by expansion. The call marker is automatically saved
6724 -- for later examination by the ABE Processing phase.
6728 -- In GNATprove mode, expansion is disabled, but we want to inline some
6729 -- subprograms to facilitate formal verification. Indirect calls through
6730 -- a subprogram type or within a generic cannot be inlined. Inlining is
6731 -- performed only for calls subject to SPARK_Mode on.
6733 if GNATprove_Mode
6736 and then not Inside_A_Generic
6737 then
6744 -- Nothing to do if the subprogram is not eligible for inlining in
6745 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6749 or else Debug_Flag_M
6750 then
6753 -- Calls cannot be inlined inside assertions, as GNATprove treats
6754 -- assertions as logic expressions. Only issue a message when the
6755 -- body has been seen, otherwise this leads to spurious messages
6756 -- on expression functions.
6760 Cannot_Inline
6764 -- Calls cannot be inlined inside default expressions
6767 Cannot_Inline
6770 -- Inlining should not be performed during preanalysis
6774 -- Do not inline calls inside expression functions or functions
6775 -- generated by the front end for subtype predicates, as this
6776 -- would prevent interpreting them as logical formulas in
6777 -- GNATprove. Only issue a message when the body has been seen,
6778 -- otherwise this leads to spurious messages on callees that
6779 -- are themselves expression functions.
6782 and then
6787 then
6790 then
6792 Cannot_Inline
6797 Cannot_Inline
6802 Cannot_Inline
6806 else
6807 Cannot_Inline
6813 -- With the one-pass inlining technique, a call cannot be
6814 -- inlined if the corresponding body has not been seen yet.
6817 Cannot_Inline
6820 -- Nothing to do if there is no body to inline, indicating that
6821 -- the subprogram is not suitable for inlining in GNATprove
6822 -- mode.
6827 -- Calls cannot be inlined inside potentially unevaluated
6828 -- expressions, as this would create complex actions inside
6829 -- expressions, that are not handled by GNATprove.
6832 Cannot_Inline
6836 -- Do not inline calls which would possibly lead to missing a
6837 -- type conversion check on an input parameter.
6840 Cannot_Inline
6844 -- Otherwise, inline the call
6846 else
6858 -----------------------------
6859 -- Resolve_Case_Expression --
6860 -----------------------------
6868 begin
6880 -- When the expression is of a scalar subtype different from the
6881 -- result subtype, then insert a conversion to ensure the generation
6882 -- of a constraint check.
6892 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6893 -- dynamically tagged must be known statically.
6901 Error_Msg_N
6915 -------------------------------
6916 -- Resolve_Character_Literal --
6917 -------------------------------
6923 begin
6924 -- Verify that the character does belong to the type of the context
6929 -- Wide_Wide_Character literals must always be defined, since the set
6930 -- of wide wide character literals is complete, i.e. if a character
6931 -- literal is accepted by the parser, then it is OK for wide wide
6932 -- character (out of range character literals are rejected).
6937 -- Always accept character literal for type Any_Character, which
6938 -- occurs in error situations and in comparisons of literals, both
6939 -- of which should accept all literals.
6944 -- For Standard.Character or a type derived from it, check that the
6945 -- literal is in range.
6952 -- For Standard.Wide_Character or a type derived from it, check that the
6953 -- literal is in range.
6960 -- If the entity is already set, this has already been resolved in a
6961 -- generic context, or comes from expansion. Nothing else to do.
6966 -- Otherwise we have a user defined character type, and we can use the
6967 -- standard visibility mechanisms to locate the referenced entity.
6969 else
6982 -- If we fall through, then the literal does not match any of the
6983 -- entries of the enumeration type. This isn't just a constraint error
6984 -- situation, it is an illegality (see RM 4.2).
6986 Error_Msg_NE
6990 ---------------------------
6991 -- Resolve_Comparison_Op --
6992 ---------------------------
6994 -- Context requires a boolean type, and plays no role in resolution.
6995 -- Processing identical to that for equality operators. The result type is
6996 -- the base type, which matters when pathological subtypes of booleans with
6997 -- limited ranges are used.
7004 begin
7005 -- If this is an intrinsic operation which is not predefined, use the
7006 -- types of its declared arguments to resolve the possibly overloaded
7007 -- operands. Otherwise the operands are unambiguous and specify the
7008 -- expected type.
7013 else
7024 -- Skip remaining processing if already set to Any_Type
7030 -- Deal with other error cases
7034 T = Any_Character
7035 then
7038 else
7046 -- Resolve the operands if types OK
7055 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
7056 -- types or array types except String.
7059 Check_SPARK_05_Restriction
7064 then
7065 Check_SPARK_05_Restriction
7069 -- Check comparison on unordered enumeration
7073 Error_Msg_NE
7080 -- Evaluate the relation (note we do this after the above check since
7081 -- this Eval call may change N to True/False. Skip this evaluation
7082 -- inside assertions, in order to keep assertions as written by users
7083 -- for tools that rely on these, e.g. GNATprove for loop invariants.
7084 -- Except evaluation is still performed even inside assertions for
7085 -- comparisons between values of universal type, which are useless
7086 -- for static analysis tools, and not supported even by GNATprove.
7090 and then
7092 then
7097 -----------------------------------------
7098 -- Resolve_Discrete_Subtype_Indication --
7099 -----------------------------------------
7101 procedure Resolve_Discrete_Subtype_Indication
7104 is
7108 begin
7116 else
7126 Error_Msg_NE
7129 -- Rewrite the constraint as a range of Typ
7130 -- to allow compilation to proceed further.
7142 else
7146 -- Additionally, we must check that the bounds are compatible
7147 -- with the given subtype, which might be different from the
7148 -- type of the context.
7152 -- ??? If the above check statically detects a Constraint_Error
7153 -- it replaces the offending bound(s) of the range R with a
7154 -- Constraint_Error node. When the itype which uses these bounds
7155 -- is frozen the resulting call to Duplicate_Subexpr generates
7156 -- a new temporary for the bounds.
7158 -- Unfortunately there are other itypes that are also made depend
7159 -- on these bounds, so when Duplicate_Subexpr is called they get
7160 -- a forward reference to the newly created temporaries and Gigi
7161 -- aborts on such forward references. This is probably sign of a
7162 -- more fundamental problem somewhere else in either the order of
7163 -- itype freezing or the way certain itypes are constructed.
7165 -- To get around this problem we call Remove_Side_Effects right
7166 -- away if either bounds of R are a Constraint_Error.
7168 declare
7172 begin
7188 -------------------------
7189 -- Resolve_Entity_Name --
7190 -------------------------
7192 -- Used to resolve identifiers and expanded names
7195 function Is_Assignment_Or_Object_Expression
7198 -- Determine whether node Context denotes an assignment statement or an
7199 -- object declaration whose expression is node Expr.
7201 ----------------------------------------
7202 -- Is_Assignment_Or_Object_Expression --
7203 ----------------------------------------
7205 function Is_Assignment_Or_Object_Expression
7208 is
7209 begin
7211 N_Object_Declaration)
7213 then
7216 -- Check whether a construct that yields a name is the expression of
7217 -- an assignment statement or an object declaration.
7220 N_Explicit_Dereference,
7221 N_Indexed_Component,
7222 N_Selected_Component,
7223 N_Slice)
7225 or else
7227 N_Unchecked_Type_Conversion)
7229 then
7230 return
7231 Is_Assignment_Or_Object_Expression
7235 -- Otherwise the context is not an assignment statement or an object
7236 -- declaration.
7238 else
7243 -- Local variables
7248 -- Start of processing for Resolve_Entity_Name
7250 begin
7251 -- If garbage from errors, set to Any_Type and return
7258 -- Replace named numbers by corresponding literals. Note that this is
7259 -- the one case where Resolve_Entity_Name must reset the Etype, since
7260 -- it is currently marked as universal.
7270 -- For enumeration literals, we need to make sure that a proper style
7271 -- check is done, since such literals are overloaded, and thus we did
7272 -- not do a style check during the first phase of analysis.
7278 -- Case of (sub)type name appearing in a context where an expression
7279 -- is expected. This is legal if occurrence is a current instance.
7280 -- See RM 8.6 (17/3).
7286 -- Any other use is an error
7288 else
7289 Error_Msg_N
7293 -- Check discriminant use if entity is discriminant in current scope,
7294 -- i.e. discriminant of record or concurrent type currently being
7295 -- analyzed. Uses in corresponding body are unrestricted.
7300 then
7303 -- A parameterless generic function cannot appear in a context that
7304 -- requires resolution.
7309 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7310 -- array types (i.e. bounds and length) are legal.
7318 or else Is_Assignment_Or_Object_Expression
7321 then
7326 -- In all other cases, just do the possible static evaluation
7328 else
7329 -- A deferred constant that appears in an expression must have a
7330 -- completion, unless it has been removed by in-place expansion of
7331 -- an aggregate. A constant that is a renaming does not need
7332 -- initialization.
7338 and then not In_Spec_Expression
7341 then
7345 then
7347 else
7348 Error_Msg_N
7358 -- When the entity appears in a parameter association, retrieve the
7359 -- related subprogram call.
7367 -- The following checks are only relevant when SPARK_Mode is on as
7368 -- they are not standard Ada legality rules.
7372 -- An effectively volatile object subject to enabled properties
7373 -- Async_Writers or Effective_Reads must appear in non-interfering
7374 -- context (SPARK RM 7.1.3(12)).
7381 then
7382 SPARK_Msg_N
7387 -- Check for possible elaboration issues with respect to reads of
7388 -- variables. The act of renaming the variable is not considered a
7389 -- read as it simply establishes an alias.
7391 if Legacy_Elaboration_Checks
7393 and then Dynamic_Elaboration_Checks
7395 then
7400 -- The variable may eventually become a constituent of a single
7401 -- protected/task type. Record the reference now and verify its
7402 -- legality when analyzing the contract of the variable
7403 -- (SPARK RM 9.3).
7409 -- A Ghost entity must appear in a specific context
7416 -- We may be resolving an entity within expanded code, so a reference to
7417 -- an entity should be ignored when calculating effective use clauses to
7418 -- avoid inappropriate marking.
7425 -------------------
7426 -- Resolve_Entry --
7427 -------------------
7439 -- If the bounds of the entry family being called depend on task
7440 -- discriminants, build a new index subtype where a discriminant is
7441 -- replaced with the value of the discriminant of the target task.
7442 -- The target task is the prefix of the entry name in the call.
7444 -----------------------
7445 -- Actual_Index_Type --
7446 -----------------------
7456 -- If the bound is given by a discriminant, replace with a reference
7457 -- to the discriminant of the same name in the target task. If the
7458 -- entry name is the target of a requeue statement and the entry is
7459 -- in the current protected object, the bound to be used is the
7460 -- discriminal of the object (see Apply_Range_Checks for details of
7461 -- the transformation).
7463 -----------------------------
7464 -- Actual_Discriminant_Ref --
7465 -----------------------------
7471 begin
7476 then
7482 then
7483 -- Note: here Bound denotes a discriminant of the corresponding
7484 -- record type tskV, whose discriminal is a formal of the
7485 -- init-proc tskVIP. What we want is the body discriminal,
7486 -- which is associated to the discriminant of the original
7487 -- concurrent type tsk.
7489 return New_Occurrence_Of
7492 else
7493 Ref :=
7503 -- Start of processing for Actual_Index_Type
7505 begin
7508 then
7511 else
7525 -- Start of processing for Resolve_Entry
7527 begin
7528 -- Find name of entry being called, and resolve prefix of name with its
7529 -- own type. The prefix can be overloaded, and the name and signature of
7530 -- the entry must be taken into account.
7534 -- Case of dealing with entry family within the current tasks
7538 else
7544 -- Entry call to an entry (or entry family) in the current task. This
7545 -- is legal even though the task will deadlock. Rewrite as call to
7546 -- current task.
7548 -- This can also be a call to an entry in an enclosing task. If this
7549 -- is a single task, we have to retrieve its name, because the scope
7550 -- of the entry is the task type, not the object. If the enclosing
7551 -- task is a task type, the identity of the task is given by its own
7552 -- self variable.
7554 -- Finally this can be a requeue on an entry of the same task or
7555 -- protected object.
7562 then
7563 -- S is an enclosing task or protected object. The concurrent
7564 -- declaration has been converted into a type declaration, and
7565 -- the object itself has an object declaration that follows
7566 -- the type in the same declarative part.
7578 -- Call to current task. Will be transformed into call to Self
7585 New_N :=
7588 Selector_Name =>
7595 then
7596 -- Use the entry name (which must be unique at this point) to find
7597 -- the prefix that returns the corresponding task/protected type.
7599 declare
7605 begin
7627 -- Generate a reference for the index when it denotes an entity
7633 -- Up to this point the expression could have been the actual in a
7634 -- simple entry call, and be given by a named association.
7638 else
7644 ------------------------
7645 -- Resolve_Entry_Call --
7646 ------------------------
7657 begin
7658 -- We kill all checks here, because it does not seem worth the effort to
7659 -- do anything better, an entry call is a big operation.
7661 Kill_All_Checks;
7663 -- Processing of the name is similar for entry calls and protected
7664 -- operation calls. Once the entity is determined, we can complete
7665 -- the resolution of the actuals.
7667 -- The selector may be overloaded, in the case of a protected object
7668 -- with overloaded functions. The type of the context is used for
7669 -- resolution.
7674 then
7675 declare
7679 begin
7698 -- Simple entry or protected operation call
7711 -- Call to member of entry family
7718 -- We cannot in general check the maximum depth of protected entry calls
7719 -- at compile time. But we can tell that any protected entry call at all
7720 -- violates a specified nesting depth of zero.
7726 -- Use context type to disambiguate a protected function that can be
7727 -- called without actuals and that returns an array type, and where the
7728 -- argument list may be an indexing of the returned value.
7733 and then
7739 and then
7740 Covers
7743 then
7744 declare
7747 begin
7748 Index_Node :=
7750 Prefix =>
7754 -- Since we are correcting a node classification error made by the
7755 -- parser, we call Replace rather than Rewrite.
7768 then
7769 -- Note the entity being called before rewriting the call, so that
7770 -- it appears used at this point.
7774 -- Rewrite as call to the precondition wrapper, adding the task
7775 -- object to the list of actuals. If the call is to a member of an
7776 -- entry family, include the index as well.
7778 declare
7782 begin
7791 New_Call :=
7793 Name =>
7798 -- Preanalyze and resolve new call. Current procedure is called
7799 -- from Resolve_Call, after which expansion will take place.
7806 -- The operation name may have been overloaded. Order the actuals
7807 -- according to the formals of the resolved entity, and set the return
7808 -- type to that of the operation.
7815 -- Reset the Is_Overloaded flag, since resolution is now completed
7817 -- Simple entry call
7822 -- Call to a member of an entry family
7832 -- Create a call reference to the entry
7840 -- Verify that a procedure call cannot masquerade as an entry
7841 -- call where an entry call is expected.
7846 then
7851 then
7856 then
7861 -- After resolution, entry calls and protected procedure calls are
7862 -- changed into entry calls, for expansion. The structure of the node
7863 -- does not change, so it can safely be done in place. Protected
7864 -- function calls must keep their structure because they are
7865 -- subexpressions.
7869 -- A protected operation that is not a function may modify the
7870 -- corresponding object, and cannot apply to a constant. If this
7871 -- is an internal call, the prefix is the type itself.
7877 then
7878 Error_Msg_N
7880 Entry_Name);
7883 declare
7886 begin
7887 Entry_Call :=
7892 -- Inherit relevant attributes from the original call
7894 Set_First_Named_Actual
7897 Set_Is_Elaboration_Checks_OK_Node
7900 Set_Is_Elaboration_Warnings_OK_Node
7903 Set_Is_SPARK_Mode_On_Node
7910 -- Protected functions can return on the secondary stack, in which case
7911 -- we must trigger the transient scope mechanism.
7913 elsif Expander_Active
7915 then
7920 -------------------------
7921 -- Resolve_Equality_Op --
7922 -------------------------
7924 -- Both arguments must have the same type, and the boolean context does
7925 -- not participate in the resolution. The first pass verifies that the
7926 -- interpretation is not ambiguous, and the type of the left argument is
7927 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7928 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7929 -- though they carry a single (universal) type. Diagnose this case here.
7937 -- The resolution rule for if expressions requires that each such must
7938 -- have a unique type. This means that if several dependent expressions
7939 -- are of a non-null anonymous access type, and the context does not
7940 -- impose an expected type (as can be the case in an equality operation)
7941 -- the expression must be rejected.
7944 -- Attempt to explain the nature of a redundant comparison with True. If
7945 -- the expression N is too complex, this routine issues a general error
7946 -- message.
7949 -- In the case of allocators and access attributes, the context must
7950 -- provide an indication of the specific access type to be used. If
7951 -- one operand is of such a "generic" access type, check whether there
7952 -- is a specific visible access type that has the same designated type.
7953 -- This is semantically dubious, and of no interest to any real code,
7954 -- but c48008a makes it all worthwhile.
7956 -------------------------
7957 -- Check_If_Expression --
7958 -------------------------
7964 begin
7971 then
7977 ------------------------
7978 -- Explain_Redundancy --
7979 ------------------------
7986 begin
7989 -- Strip the operand down to an entity
7991 loop
7994 else
7999 -- The construct denotes an entity
8004 -- Do not generate an error message when the comparison is done
8005 -- against the enumeration literal Standard.True.
8009 -- Build a customized error message
8036 -- The construct is too complex to disect, issue a general message
8038 else
8043 -----------------------------
8044 -- Find_Unique_Access_Type --
8045 -----------------------------
8052 begin
8054 E_Access_Attribute_Type)
8055 then
8059 E_Access_Attribute_Type)
8060 then
8062 else
8074 then
8087 -- Start of processing for Resolve_Equality_Op
8089 begin
8100 T = Any_Character
8101 then
8104 else
8113 then
8122 -- If expressions must have a single type, and if the context does
8123 -- not impose one the dependent expressions cannot be anonymous
8124 -- access types.
8126 -- Why no similar processing for case expressions???
8130 E_Anonymous_Access_Subprogram_Type)
8132 E_Anonymous_Access_Subprogram_Type)
8133 then
8141 -- In SPARK, equality operators = and /= for array types other than
8142 -- String are only defined when, for each index position, the
8143 -- operands have equal static bounds.
8147 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8148 -- operation if not needed.
8156 then
8157 Check_SPARK_05_Restriction
8162 -- If the unique type is a class-wide type then it will be expanded
8163 -- into a dispatching call to the predefined primitive. Therefore we
8164 -- check here for potential violation of such restriction.
8170 -- Only warn for redundant equality comparison to True for objects
8171 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8172 -- other expressions, it may be a matter of preference to write
8173 -- "Expr = True" or "Expr".
8175 if Warn_On_Redundant_Constructs
8180 and then
8182 or else
8184 then
8185 Error_Msg_N -- CODEFIX
8195 -- If this is an inequality, it may be the implicit inequality
8196 -- created for a user-defined operation, in which case the corres-
8197 -- ponding equality operation is not intrinsic, and the operation
8198 -- cannot be constant-folded. Else fold.
8203 or else Is_Intrinsic_Subprogram
8205 then
8211 then
8215 -- Ada 2005: If one operand is an anonymous access type, convert the
8216 -- other operand to it, to ensure that the underlying types match in
8217 -- the back-end. Same for access_to_subprogram, and the conversion
8218 -- verifies that the types are subtype conformant.
8220 -- We apply the same conversion in the case one of the operands is a
8221 -- private subtype of the type of the other.
8223 -- Why the Expander_Active test here ???
8225 if Expander_Active
8226 and then
8228 E_Anonymous_Access_Subprogram_Type)
8230 then
8250 ----------------------------------
8251 -- Resolve_Explicit_Dereference --
8252 ----------------------------------
8260 -- The candidate prefix type, if overloaded
8265 begin
8269 -- A useful optimization: check whether the dereference denotes an
8270 -- element of a container, and if so rewrite it as a call to the
8271 -- corresponding Element function.
8273 -- Disabled for now, on advice of ARG. A more restricted form of the
8274 -- predicate might be acceptable ???
8276 -- if Is_Container_Element (N) then
8277 -- return;
8278 -- end if;
8282 -- Use the context type to select the prefix that has the correct
8283 -- designated type. Keep the first match, which will be the inner-
8284 -- most.
8291 then
8296 -- Remove access types that do not match, but preserve access
8297 -- to subprogram interpretations, in case a further dereference
8298 -- is needed (see below).
8311 else
8312 -- If no interpretation covers the designated type of the prefix,
8313 -- this is the pathological case where not all implementations of
8314 -- the prefix allow the interpretation of the node as a call. Now
8315 -- that the expected type is known, Remove other interpretations
8316 -- from prefix, rewrite it as a call, and resolve again, so that
8317 -- the proper call node is generated.
8328 New_N :=
8330 Name =>
8341 -- If not overloaded, resolve P with its own type
8343 else
8347 -- If the prefix might be null, add an access check
8351 then
8355 -- If the designated type is a packed unconstrained array type, and the
8356 -- explicit dereference is not in the context of an attribute reference,
8357 -- then we must compute and set the actual subtype, since it is needed
8358 -- by Gigi. The reason we exclude the attribute case is that this is
8359 -- handled fine by Gigi, and in fact we use such attributes to build the
8360 -- actual subtype. We also exclude generated code (which builds actual
8361 -- subtypes directly if they are needed).
8368 then
8374 -- Note: No Eval processing is required for an explicit dereference,
8375 -- because such a name can never be static.
8379 -------------------------------------
8380 -- Resolve_Expression_With_Actions --
8381 -------------------------------------
8384 begin
8387 -- If N has no actions, and its expression has been constant folded,
8388 -- then rewrite N as just its expression. Note, we can't do this in
8389 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8390 -- Expression (N) to be expanded again.
8394 then
8399 ----------------------------------
8400 -- Resolve_Generalized_Indexing --
8401 ----------------------------------
8409 begin
8410 -- In ASIS mode, propagate the information about the indexes back to
8411 -- to the original indexing node. The generalized indexing is either
8412 -- a function call, or a dereference of one. The actuals include the
8413 -- prefix of the original node, which is the container expression.
8422 loop
8431 -- If expression is to be reanalyzed, reset Generalized_Indexing
8432 -- to recreate call node, as is the case when the expression is
8433 -- part of an expression function.
8442 else
8448 ---------------------------
8449 -- Resolve_If_Expression --
8450 ---------------------------
8459 begin
8460 -- Defend against malformed expressions
8478 -- When the "then" expression is of a scalar subtype different from the
8479 -- result subtype, then insert a conversion to ensure the generation of
8480 -- a constraint check. The same is done for the else part below, again
8481 -- comparing subtypes rather than base types.
8488 -- If ELSE expression present, just resolve using the determined type
8489 -- If type is universal, resolve to any member of the class.
8498 else
8508 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8509 -- dynamically tagged must be known statically.
8514 then
8520 -- If no ELSE expression is present, root type must be Standard.Boolean
8521 -- and we provide a Standard.True result converted to the appropriate
8522 -- Boolean type (in case it is a derived boolean type).
8525 Else_Expr :=
8530 else
8544 -------------------------------
8545 -- Resolve_Indexed_Component --
8546 -------------------------------
8554 begin
8562 -- Use the context type to select the prefix that yields the correct
8563 -- component type.
8565 declare
8572 begin
8579 and then
8580 Covers
8583 then
8592 else
8598 else
8609 else
8616 -- If prefix is access type, dereference to get real array type.
8617 -- Note: we do not apply an access check because the expander always
8618 -- introduces an explicit dereference, and the check will happen there.
8624 -- If name was overloaded, set component type correctly now
8625 -- If a misplaced call to an entry family (which has no index types)
8626 -- return. Error will be diagnosed from calling context.
8630 else
8637 -- The prefix may have resolved to a string literal, in which case its
8638 -- etype has a special representation. This is only possible currently
8639 -- if the prefix is a static concatenation, written in functional
8640 -- notation.
8645 else
8652 else
8663 -- Do not generate the warning on suspicious index if we are analyzing
8664 -- package Ada.Tags; otherwise we will report the warning with the
8665 -- Prims_Ptr field of the dispatch table.
8668 or else not
8670 Ada_Tags)
8671 then
8676 -- If the array type is atomic, and the component is not atomic, then
8677 -- this is worth a warning, since we have a situation where the access
8678 -- to the component may cause extra read/writes of the atomic array
8679 -- object, or partial word accesses, which could be unexpected.
8685 and then Has_Atomic_Components
8688 then
8689 Error_Msg_N
8691 Error_Msg_N
8696 -----------------------------
8697 -- Resolve_Integer_Literal --
8698 -----------------------------
8701 begin
8706 --------------------------------
8707 -- Resolve_Intrinsic_Operator --
8708 --------------------------------
8717 -- If the operand is a literal, it cannot be the expression in a
8718 -- conversion. Use a qualified expression instead.
8720 ---------------------
8721 -- Convert_Operand --
8722 ---------------------
8728 begin
8730 Res :=
8736 else
8743 -- Start of processing for Resolve_Intrinsic_Operator
8745 begin
8746 -- We must preserve the original entity in a generic setting, so that
8747 -- the legality of the operation can be verified in an instance.
8762 -- If the result or operand types are private, rewrite with unchecked
8763 -- conversions on the operands and the result, to expose the proper
8764 -- underlying numeric type.
8769 then
8774 else
8795 then
8796 -- Add explicit conversion where needed, and save interpretations in
8797 -- case operands are overloaded.
8804 else
8810 else
8820 else
8825 --------------------------------------
8826 -- Resolve_Intrinsic_Unary_Operator --
8827 --------------------------------------
8829 procedure Resolve_Intrinsic_Unary_Operator
8832 is
8837 begin
8856 else
8861 ------------------------
8862 -- Resolve_Logical_Op --
8863 ------------------------
8868 begin
8871 -- Predefined operations on scalar types yield the base type. On the
8872 -- other hand, logical operations on arrays yield the type of the
8873 -- arguments (and the context).
8877 else
8881 -- The following test is required because the operands of the operation
8882 -- may be literals, in which case the resulting type appears to be
8883 -- compatible with a signed integer type, when in fact it is compatible
8884 -- only with modular types. If the context itself is universal, the
8885 -- operation is illegal.
8893 Error_Msg_N
8901 then
8905 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8906 -- is active and the result type is standard Boolean (do not mess with
8907 -- ops that return a nonstandard Boolean type, because something strange
8908 -- is going on).
8910 -- Note: you might expect this replacement to be done during expansion,
8911 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8912 -- is used, no part of the right operand of an "and" or "or" operator
8913 -- should be executed if the left operand would short-circuit the
8914 -- evaluation of the corresponding "and then" or "or else". If we left
8915 -- the replacement to expansion time, then run-time checks associated
8916 -- with such operands would be evaluated unconditionally, due to being
8917 -- before the condition prior to the rewriting as short-circuit forms
8918 -- during expansion.
8920 if Short_Circuit_And_Or
8923 then
8924 -- Mark the corresponding putative SCO operator as truly a logical
8925 -- (and short-circuit) operator.
8938 -- Case of OR changed to OR ELSE
8940 else
8948 -- Return now, since analysis of the rewritten ops will take care of
8949 -- other reference bookkeeping and expression folding.
8964 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8965 -- only when both operands have same static lower and higher bounds. Of
8966 -- course the types have to match, so only check if operands are
8967 -- compatible and the node itself has no errors.
8971 then
8972 declare
8976 begin
8977 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8978 -- operation if not needed.
8985 then
8986 Check_SPARK_05_Restriction
8993 ---------------------------
8994 -- Resolve_Membership_Op --
8995 ---------------------------
8997 -- The context can only be a boolean type, and does not determine the
8998 -- arguments. Arguments should be unambiguous, but the preference rule for
8999 -- universal types applies.
9009 -- Analysis has determined a unique type for the left operand. Use it to
9010 -- resolve the disjuncts.
9012 ----------------------------
9013 -- Resolve_Set_Membership --
9014 ----------------------------
9020 begin
9021 -- If the left operand is overloaded, find type compatible with not
9022 -- overloaded alternative of the right operand.
9031 else
9036 -- Unclear how to resolve expression if all alternatives are also
9037 -- overloaded.
9043 else
9052 -- Alternative is an expression, a range
9053 -- or a subtype mark.
9057 then
9064 -- Check for duplicates for discrete case
9067 declare
9076 begin
9077 -- Loop checking duplicates. This is quadratic, but giant sets
9078 -- are unlikely in this context so it's a reasonable choice.
9085 N_Character_Literal)
9087 then
9104 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
9105 -- limited types, evaluation of a membership test uses the predefined
9106 -- equality for the type. This may be confusing to users, and the
9107 -- following warning appears useful for the most common case.
9111 then
9112 Error_Msg_NE
9114 Error_Msg_N
9119 -- Start of processing for Resolve_Membership_Op
9121 begin
9127 Resolve_Set_Membership;
9131 and then
9133 or else
9136 then
9139 -- Ada 2005 (AI-251): Support the following case:
9141 -- type I is interface;
9142 -- type T is tagged ...
9144 -- function Test (O : I'Class) is
9145 -- begin
9146 -- return O in T'Class.
9147 -- end Test;
9149 -- In this case we have nothing else to do. The membership test will be
9150 -- done at run time.
9156 then
9158 else
9162 -- If mixed-mode operations are present and operands are all literal,
9163 -- the only interpretation involves Duration, which is probably not
9164 -- the intention of the programmer.
9179 then
9185 else
9190 -- Here after resolving membership operation
9197 ------------------
9198 -- Resolve_Null --
9199 ------------------
9204 begin
9205 -- Handle restriction against anonymous null access values This
9206 -- restriction can be turned off using -gnatdj.
9208 -- Ada 2005 (AI-231): Remove restriction
9211 and then not Debug_Flag_J
9214 then
9215 -- In the common case of a call which uses an explicitly null value
9216 -- for an access parameter, give specialized error message.
9219 Error_Msg_N
9222 -- Standard message for all other cases (are there any?)
9224 else
9225 Error_Msg_N
9230 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9231 -- assignment to a null-excluding object.
9236 then
9239 -- Decide whether to generate an if_statement around our
9240 -- null-excluding check to avoid them on certain internal object
9241 -- declarations by looking at the type the current Init_Proc
9242 -- belongs to.
9244 -- Generate:
9245 -- if T1b_skip_null_excluding_check then
9246 -- [constraint_error "access check failed"]
9247 -- end if;
9249 if Needs_Conditional_Null_Excluding_Check
9251 then
9254 Condition =>
9256 New_External_Name
9258 Then_Statements =>
9259 New_List (
9263 -- Otherwise, simply create the check
9265 else
9270 else
9271 Insert_Action
9279 -- In a distributed context, null for a remote access to subprogram may
9280 -- need to be replaced with a special record aggregate. In this case,
9281 -- return after having done the transformation.
9286 then
9290 -- The null literal takes its type from the context
9295 -----------------------
9296 -- Resolve_Op_Concat --
9297 -----------------------
9301 -- We wish to avoid deep recursion, because concatenations are often
9302 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9303 -- operands nonrecursively until we find something that is not a simple
9304 -- concatenation (A in this case). We resolve that, and then walk back
9305 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9306 -- to do the rest of the work at each level. The Parent pointers allow
9307 -- us to avoid recursion, and thus avoid running out of memory. See also
9308 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9313 begin
9314 -- The following code is equivalent to:
9316 -- Resolve_Op_Concat_First (NN, Typ);
9317 -- Resolve_Op_Concat_Arg (N, ...);
9318 -- Resolve_Op_Concat_Rest (N, Typ);
9320 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9321 -- operand is a concatenation.
9323 -- Walk down left operands
9325 loop
9334 -- Now (given the above example) NN is A&B and Op1 is A
9336 -- First resolve Op1 ...
9340 -- ... then walk NN back up until we reach N (where we started), calling
9341 -- Resolve_Op_Concat_Rest along the way.
9343 loop
9350 Check_SPARK_05_Restriction
9355 ---------------------------
9356 -- Resolve_Op_Concat_Arg --
9357 ---------------------------
9359 procedure Resolve_Op_Concat_Arg
9364 is
9368 begin
9370 if Is_Comp
9374 then
9376 else
9380 -- If both Array & Array and Array & Component are visible, there is a
9381 -- potential ambiguity that must be reported.
9386 then
9390 -- If the operation is user-defined and not overloaded use its
9391 -- profile. The operation may be a renaming, in which case it has
9392 -- been rewritten, and we want the original profile.
9397 then
9399 Etype
9403 -- Otherwise an aggregate may match both the array type and the
9404 -- component type.
9406 else
9411 else
9415 then
9416 declare
9421 begin
9426 -- Special-case the error message when the overloading is
9427 -- caused by a function that yields an array and can be
9428 -- called without parameters.
9433 Error_Msg_NE
9435 Error_Msg_NE
9439 else
9447 or else
9449 then
9450 Error_Msg_N -- CODEFIX
9468 else
9473 else
9477 -- Concatenation is restricted in SPARK: each operand must be either a
9478 -- string literal, the name of a string constant, a static character or
9479 -- string expression, or another concatenation. Arg cannot be a
9480 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9481 -- separately on each final operand, past concatenation operations.
9485 Check_SPARK_05_Restriction
9493 then
9494 Check_SPARK_05_Restriction
9498 -- Do not issue error on an operand that is neither a character nor a
9499 -- string, as the error is issued in Resolve_Op_Concat.
9501 else
9508 -----------------------------
9509 -- Resolve_Op_Concat_First --
9510 -----------------------------
9517 begin
9518 -- The parser folds an enormous sequence of concatenations of string
9519 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9520 -- in the right operand. If the expression resolves to a predefined "&"
9521 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9522 -- we give an error. See P_Simple_Expression in Par.Ch4.
9527 then
9542 ----------------------------
9543 -- Resolve_Op_Concat_Rest --
9544 ----------------------------
9550 begin
9559 -- If this is not a static concatenation, but the result is a string
9560 -- type (and not an array of strings) ensure that static string operands
9561 -- have their subtypes properly constructed.
9565 then
9571 ----------------------
9572 -- Resolve_Op_Expon --
9573 ----------------------
9578 begin
9579 -- Catch attempts to do fixed-point exponentiation with universal
9580 -- operands, which is a case where the illegality is not caught during
9581 -- normal operator analysis. This is not done in preanalysis mode
9582 -- since the tree is not fully decorated during preanalysis.
9594 then
9604 then
9611 then
9615 -- We do the resolution using the base type, because intermediate values
9616 -- in expressions are always of the base type, not a subtype of it.
9621 -- For integer types, right argument must be in Natural range
9636 -- Evaluate the exponentiation operator for dimensioned type
9639 else
9643 -- Set overflow checking bit. Much cleverer code needed here eventually
9644 -- and perhaps the Resolve routines should be separated for the various
9645 -- arithmetic operations, since they will need different processing. ???
9654 --------------------
9655 -- Resolve_Op_Not --
9656 --------------------
9662 -- This function determines if the parent node is a boolean operator or
9663 -- operation (comparison op, membership test, or short circuit form) and
9664 -- the not in question is the left operand of this operation. Note that
9665 -- if the not is in parens, then false is returned.
9667 -----------------------
9668 -- Parent_Is_Boolean --
9669 -----------------------
9672 begin
9676 else
9678 when N_And_Then
9679 | N_In
9680 | N_Not_In
9681 | N_Op_And
9682 | N_Op_Eq
9683 | N_Op_Ge
9684 | N_Op_Gt
9685 | N_Op_Le
9686 | N_Op_Lt
9687 | N_Op_Ne
9688 | N_Op_Or
9689 | N_Op_Xor
9690 | N_Or_Else
9691 =>
9700 -- Start of processing for Resolve_Op_Not
9702 begin
9703 -- Predefined operations on scalar types yield the base type. On the
9704 -- other hand, logical operations on arrays yield the type of the
9705 -- arguments (and the context).
9709 else
9713 -- Straightforward case of incorrect arguments
9720 -- Special case of probable missing parens
9724 Error_Msg_N
9727 else
9728 Error_Msg_N
9735 -- OK resolution of NOT
9737 else
9738 -- Warn if non-boolean types involved. This is a case like not a < b
9739 -- where a and b are modular, where we will get (not a) < b and most
9740 -- likely not (a < b) was intended.
9742 if Warn_On_Questionable_Missing_Parens
9744 and then Parent_Is_Boolean
9745 then
9749 -- Warn on double negation if checking redundant constructs
9751 if Warn_On_Redundant_Constructs
9756 then
9760 -- Complete resolution and evaluation of NOT
9770 -----------------------------
9771 -- Resolve_Operator_Symbol --
9772 -----------------------------
9774 -- Nothing to be done, all resolved already
9780 begin
9784 ----------------------------------
9785 -- Resolve_Qualified_Expression --
9786 ----------------------------------
9794 begin
9797 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9798 -- operation if not needed.
9805 then
9806 Check_SPARK_05_Restriction
9810 -- A qualified expression requires an exact match of the type, class-
9811 -- wide matching is not allowed. However, if the qualifying type is
9812 -- specific and the expression has a class-wide type, it may still be
9813 -- okay, since it can be the result of the expansion of a call to a
9814 -- dispatching function, so we also have to check class-wideness of the
9815 -- type of the expression's original node.
9818 or else
9822 then
9826 -- If the target type is unconstrained, then we reset the type of the
9827 -- result from the type of the expression. For other cases, the actual
9828 -- subtype of the expression is the target type.
9832 then
9839 -- If we still have a qualified expression after the static evaluation,
9840 -- then apply a scalar range check if needed. The reason that we do this
9841 -- after the Eval call is that otherwise, the application of the range
9842 -- check may convert an illegal static expression and result in warning
9843 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9849 -- Finally, check whether a predicate applies to the target type. This
9850 -- comes from AI12-0100. As for type conversions, check the enclosing
9851 -- context to prevent an infinite expansion.
9857 or else
9859 then
9862 -- In the case of a qualified expression in an allocator, the check
9863 -- is applied when expanding the allocator, so avoid redundant check.
9867 then
9873 ------------------------------
9874 -- Resolve_Raise_Expression --
9875 ------------------------------
9878 begin
9882 else
9887 -------------------
9888 -- Resolve_Range --
9889 -------------------
9896 -- Returns True if N is of the form X'First .. X'Last where X is the
9897 -- same entity for both attributes.
9899 --------------------
9900 -- First_Last_Ref --
9901 --------------------
9907 begin
9912 then
9913 declare
9916 begin
9920 then
9929 -- Start of processing for Resolve_Range
9931 begin
9934 -- The lower bound should be in Typ. The higher bound can be in Typ's
9935 -- base type if the range is null. It may still be invalid if it is
9936 -- higher than the lower bound. This is checked later in the context in
9937 -- which the range appears.
9942 -- Reanalyze the lower bound after both bounds have been analyzed, so
9943 -- that the range is known to be static or not by now. This may trigger
9944 -- more compile-time evaluation, which is useful for static analysis
9945 -- with GNATprove. This is not needed for compilation or static analysis
9946 -- with CodePeer, as full expansion does that evaluation then.
9953 -- Check for inappropriate range on unordered enumeration type
9957 -- Exclude X'First .. X'Last if X is the same entity for both
9959 and then not First_Last_Ref
9960 then
9962 Error_Msg_NE
9969 -- We have to check the bounds for being within the base range as
9970 -- required for a non-static context. Normally this is automatic and
9971 -- done as part of evaluating expressions, but the N_Range node is an
9972 -- exception, since in GNAT we consider this node to be a subexpression,
9973 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9974 -- this, but that would put the test on the main evaluation path for
9975 -- expressions.
9980 -- Check for an ambiguous range over character literals. This will
9981 -- happen with a membership test involving only literals.
9989 -- If bounds are static, constant-fold them, so size computations are
9990 -- identical between front-end and back-end. Do not perform this
9991 -- transformation while analyzing generic units, as type information
9992 -- would be lost when reanalyzing the constant node in the instance.
10005 --------------------------
10006 -- Resolve_Real_Literal --
10007 --------------------------
10012 begin
10013 -- Special processing for fixed-point literals to make sure that the
10014 -- value is an exact multiple of small where this is required. We skip
10015 -- this for the universal real case, and also for generic types.
10021 then
10022 declare
10029 begin
10030 -- Case of literal is not an exact multiple of the Small
10034 -- For a source program literal for a decimal fixed-point type,
10035 -- this is statically illegal (RM 4.9(36)).
10040 then
10044 -- Generate a warning if literal from source
10047 and then Warn_On_Bad_Fixed_Value
10048 then
10049 Error_Msg_N
10051 N);
10054 -- Replace literal by a value that is the exact representation
10055 -- of a value of the type, i.e. a multiple of the small value,
10056 -- by truncation, since Machine_Rounds is false for all GNAT
10057 -- fixed-point types (RM 4.9(38)).
10067 -- In all cases, set the corresponding integer field
10073 -- Now replace the actual type by the expected type as usual
10079 -----------------------
10080 -- Resolve_Reference --
10081 -----------------------
10086 begin
10087 -- Replace general access with specific type
10095 -- If we are taking the reference of a volatile entity, then treat it as
10096 -- a potential modification of this entity. This is too conservative,
10097 -- but necessary because remove side effects can cause transformations
10098 -- of normal assignments into reference sequences that otherwise fail to
10099 -- notice the modification.
10106 --------------------------------
10107 -- Resolve_Selected_Component --
10108 --------------------------------
10123 -- Check whether this is the initialization of a component within an
10124 -- init proc (by assignment or call to another init proc). If true,
10125 -- there is no need for a discriminant check.
10127 --------------------
10128 -- Init_Component --
10129 --------------------
10132 begin
10133 return Inside_Init_Proc
10139 -- Start of processing for Resolve_Selected_Component
10141 begin
10144 -- Use the context type to select the prefix that has a selector
10145 -- of the correct name and type.
10153 else
10157 -- Locate selected component. For a private prefix the selector
10158 -- can denote a discriminant.
10162 -- The visible components of a class-wide type are those of
10163 -- the root type.
10173 then
10180 else
10184 Error_Msg_N
10189 else
10192 -- There may be an implicit dereference. Retrieve
10193 -- designated record type.
10197 else
10203 -- Resolution chooses the new interpretation.
10204 -- Find the component with the right name.
10209 loop
10226 -- There must be a legal interpretation at this point
10233 -- The type of the context and that of the component are
10234 -- compatible and in general identical, but if they are anonymous
10235 -- access-to-subprogram types, the relevant type is that of the
10236 -- component. This matters in Unnest_Subprograms mode, where the
10237 -- relevant context is the one in which the type is declared, not
10238 -- the point of use. This determines what activation record to use.
10244 else
10245 -- Resolve prefix with its type
10250 -- Generate cross-reference. We needed to wait until full overloading
10251 -- resolution was complete to do this, since otherwise we can't tell if
10252 -- we are an lvalue or not.
10256 else
10260 -- If prefix is an access type, the node will be transformed into an
10261 -- explicit dereference during expansion. The type of the node is the
10262 -- designated type of that of the prefix.
10267 else
10271 -- Set flag for expander if discriminant check required on a component
10272 -- appearing within a variant.
10278 and then
10281 and then not Init_Component
10282 then
10290 -- If the prefix is a record conversion, this may be a renamed
10291 -- discriminant whose bounds differ from those of the original
10292 -- one, so we must ensure that a range check is performed.
10297 then
10301 -- Note: No Eval processing is required, because the prefix is of a
10302 -- record type, or protected type, and neither can possibly be static.
10304 -- If the record type is atomic, and the component is non-atomic, then
10305 -- this is worth a warning, since we have a situation where the access
10306 -- to the component may cause extra read/writes of the atomic array
10307 -- object, or partial word accesses, both of which may be unexpected.
10313 then
10314 Error_Msg_N
10317 Error_Msg_N
10325 -------------------
10326 -- Resolve_Shift --
10327 -------------------
10334 begin
10335 -- We do the resolution using the base type, because intermediate values
10336 -- in expressions always are of the base type, not a subtype of it.
10349 ---------------------------
10350 -- Resolve_Short_Circuit --
10351 ---------------------------
10358 begin
10359 -- Ensure all actions associated with the left operand (e.g.
10360 -- finalization of transient objects) are fully evaluated locally within
10361 -- an expression with actions. This is particularly helpful for coverage
10362 -- analysis. However this should not happen in generics or if option
10363 -- Minimize_Expression_With_Actions is set.
10366 declare
10368 begin
10376 -- Set Comes_From_Source on L to preserve warnings for unset
10377 -- reference.
10386 -- Check for issuing warning for always False assert/check, this happens
10387 -- when assertions are turned off, in which case the pragma Assert/Check
10388 -- was transformed into:
10390 -- if False and then <condition> then ...
10392 -- and we detect this pattern
10394 if Warn_On_Assertion_Failure
10401 then
10402 declare
10405 begin
10406 -- Special handling of Asssert pragma
10410 then
10411 declare
10413 Original_Node
10414 (Expression
10417 begin
10418 -- Don't warn if original condition is explicit False,
10419 -- since obviously the failure is expected in this case.
10423 then
10426 -- Issue warning. We do not want the deletion of the
10427 -- IF/AND-THEN to take this message with it. We achieve this
10428 -- by making sure that the expanded code points to the Sloc
10429 -- of the expression, not the original pragma.
10431 else
10432 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10433 -- The source location of the expression is not usually
10434 -- the best choice here. For example, it gets located on
10435 -- the last AND keyword in a chain of boolean expressiond
10436 -- AND'ed together. It is best to put the message on the
10437 -- first character of the assertion, which is the effect
10438 -- of the First_Node call here.
10440 Error_Msg_F
10442 Expression
10447 -- Similar processing for Check pragma
10451 then
10452 -- Don't want to warn if original condition is explicit False
10454 declare
10456 Original_Node
10457 (Expression
10459 begin
10462 then
10465 -- Post warning
10467 else
10468 -- Again use Error_Msg_F rather than Error_Msg_N, see
10469 -- comment above for an explanation of why we do this.
10471 Error_Msg_F
10473 Expression
10481 -- Continue with processing of short circuit
10490 -------------------
10491 -- Resolve_Slice --
10492 -------------------
10501 begin
10504 -- Use the context type to select the prefix that yields the correct
10505 -- array type.
10507 declare
10514 begin
10522 then
10530 else
10535 else
10546 else
10556 -- If the prefix is an access to an unconstrained array, we must use
10557 -- the actual subtype of the object to perform the index checks. The
10558 -- object denoted by the prefix is implicit in the node, so we build
10559 -- an explicit representation for it in order to compute the actual
10560 -- subtype.
10565 declare
10569 begin
10580 then
10583 -- If the name is a selected component that depends on discriminants,
10584 -- build an actual subtype for it. This can happen only when the name
10585 -- itself is overloaded; otherwise the actual subtype is created when
10586 -- the selected component is analyzed.
10589 and then Full_Analysis
10591 then
10592 declare
10595 begin
10600 -- Maybe this should just be "else", instead of checking for the
10601 -- specific case of slice??? This is needed for the case where the
10602 -- prefix is an Image attribute, which gets expanded to a slice, and so
10603 -- has a constrained subtype which we want to use for the slice range
10604 -- check applied below (the range check won't get done if the
10605 -- unconstrained subtype of the 'Image is used).
10611 -- Obtain the type of the array index
10615 else
10619 -- If name was overloaded, set slice type correctly now
10623 -- Handle the generation of a range check that compares the array index
10624 -- against the discrete_range. The check is not applied to internally
10625 -- built nodes associated with the expansion of dispatch tables. Check
10626 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10627 -- the unit.
10629 if Tagged_Type_Expansion
10635 then
10638 -- The discrete_range is specified by a subtype indication. Create a
10639 -- shallow copy and inherit the type, parent and source location from
10640 -- the discrete_range. This ensures that the range check is inserted
10641 -- relative to the slice and that the runtime exception points to the
10642 -- proper construct.
10651 -- The discrete_range is a regular range. Resolve the bounds and remove
10652 -- their side effects.
10654 else
10671 -- Check bad use of type with predicates
10673 declare
10676 begin
10679 then
10681 else
10686 Bad_Predicated_Subtype_Use
10691 -- Otherwise here is where we check suspicious indexes
10702 ----------------------------
10703 -- Resolve_String_Literal --
10704 ----------------------------
10715 begin
10716 -- For a string appearing in a concatenation, defer creation of the
10717 -- string_literal_subtype until the end of the resolution of the
10718 -- concatenation, because the literal may be constant-folded away. This
10719 -- is a useful optimization for long concatenation expressions.
10721 -- If the string is an aggregate built for a single character (which
10722 -- happens in a non-static context) or a is null string to which special
10723 -- checks may apply, we build the subtype. Wide strings must also get a
10724 -- string subtype if they come from a one character aggregate. Strings
10725 -- generated by attributes might be static, but it is often hard to
10726 -- determine whether the enclosing context is static, so we generate
10727 -- subtypes for them as well, thus losing some rarer optimizations ???
10728 -- Same for strings that come from a static conversion.
10730 Need_Check :=
10739 -- If the resolving type is itself a string literal subtype, we can just
10740 -- reuse it, since there is no point in creating another.
10746 and then not Need_Check
10748 N_Attribute_Reference,
10749 N_Qualified_Expression,
10750 N_Type_Conversion)
10751 then
10754 -- Do not generate a string literal subtype for the default expression
10755 -- of a formal parameter in GNATprove mode. This is because the string
10756 -- subtype is associated with the freezing actions of the subprogram,
10757 -- however freezing is disabled in GNATprove mode and as a result the
10758 -- subtype is unavailable.
10760 elsif GNATprove_Mode
10762 then
10765 -- Otherwise we must create a string literal subtype. Note that the
10766 -- whole idea of string literal subtypes is simply to avoid the need
10767 -- for building a full fledged array subtype for each literal.
10769 else
10775 or else Need_Check
10776 then
10783 then
10789 -- The validity of a null string has been checked in the call to
10790 -- Eval_String_Literal.
10795 -- Always accept string literal with component type Any_Character, which
10796 -- occurs in error situations and in comparisons of literals, both of
10797 -- which should accept all literals.
10802 -- If the type is bit-packed, then we always transform the string
10803 -- literal into a full fledged aggregate.
10808 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10810 else
10811 -- For Standard.Wide_Wide_String, or any other type whose component
10812 -- type is Standard.Wide_Wide_Character, we know that all the
10813 -- characters in the string must be acceptable, since the parser
10814 -- accepted the characters as valid character literals.
10819 -- For the case of Standard.String, or any other type whose component
10820 -- type is Standard.Character, we must make sure that there are no
10821 -- wide characters in the string, i.e. that it is entirely composed
10822 -- of characters in range of type Character.
10824 -- If the string literal is the result of a static concatenation, the
10825 -- test has already been performed on the components, and need not be
10826 -- repeated.
10830 then
10834 -- If we are out of range, post error. This is one of the
10835 -- very few places that we place the flag in the middle of
10836 -- a token, right under the offending wide character. Not
10837 -- quite clear if this is right wrt wide character encoding
10838 -- sequences, but it's only an error message.
10840 Error_Msg
10847 -- For the case of Standard.Wide_String, or any other type whose
10848 -- component type is Standard.Wide_Character, we must make sure that
10849 -- there are no wide characters in the string, i.e. that it is
10850 -- entirely composed of characters in range of type Wide_Character.
10852 -- If the string literal is the result of a static concatenation,
10853 -- the test has already been performed on the components, and need
10854 -- not be repeated.
10858 then
10862 -- If we are out of range, post error. This is one of the
10863 -- very few places that we place the flag in the middle of
10864 -- a token, right under the offending wide character.
10866 -- This is not quite right, because characters in general
10867 -- will take more than one character position ???
10869 Error_Msg
10876 -- If the root type is not a standard character, then we will convert
10877 -- the string into an aggregate and will let the aggregate code do
10878 -- the checking. Standard Wide_Wide_Character is also OK here.
10880 else
10884 -- See if the component type of the array corresponding to the string
10885 -- has compile time known bounds. If yes we can directly check
10886 -- whether the evaluation of the string will raise constraint error.
10887 -- Otherwise we need to transform the string literal into the
10888 -- corresponding character aggregate and let the aggregate code do
10889 -- the checking. We use the same transformation if the component
10890 -- type has a static predicate, which will be applied to each
10891 -- character when the aggregate is resolved.
10895 -- Check for the case of full range, where we are definitely OK
10901 -- Here the range is not the complete base type range, so check
10903 declare
10911 begin
10914 then
10920 then
10921 Apply_Compile_Time_Constraint_Error
10923 CE_Range_Check_Failed,
10936 -- If we got here we meed to transform the string literal into the
10937 -- equivalent qualified positional array aggregate. This is rather
10938 -- heavy artillery for this situation, but it is hard work to avoid.
10940 declare
10945 begin
10946 -- Build the character literals, we give them source locations that
10947 -- correspond to the string positions, which is a bit tricky given
10948 -- the possible presence of wide character escape sequences.
10962 -- Should we have a call to Skip_Wide here ???
10964 -- ??? else
10965 -- Skip_Wide (P);
10973 Expression =>
10980 -------------------------
10981 -- Resolve_Target_Name --
10982 -------------------------
10985 begin
10989 -----------------------------
10990 -- Resolve_Type_Conversion --
10991 -----------------------------
11003 -- Set to False to suppress cases where we want to suppress the test
11004 -- for redundancy to avoid possible false positives on this warning.
11006 begin
11007 if not Conv_OK
11009 then
11013 -- If the Operand Etype is Universal_Fixed, then the conversion is
11014 -- never redundant. We need this check because by the time we have
11015 -- finished the rather complex transformation, the conversion looks
11016 -- redundant when it is not.
11021 -- If the operand is marked as Any_Fixed, then special processing is
11022 -- required. This is also a case where we suppress the test for a
11023 -- redundant conversion, since most certainly it is not redundant.
11028 -- Mixed-mode operation involving a literal. Context must be a fixed
11029 -- type which is applied to the literal subsequently.
11031 -- Multiplication and division involving two fixed type operands must
11032 -- yield a universal real because the result is computed in arbitrary
11033 -- precision.
11039 then
11045 or else
11047 then
11048 -- Return if expression is ambiguous
11053 -- If nothing else, the available fixed type is Duration
11055 else
11059 -- Resolve the real operand with largest available precision
11063 else
11069 -- If the operand is a literal (it could be a non-static and
11070 -- illegal exponentiation) check whether the use of Duration
11071 -- is potentially inaccurate.
11076 then
11077 Error_Msg_N
11080 Error_Msg_N
11087 then
11090 else
11099 -- In SPARK, a type conversion between array types should be restricted
11100 -- to types which have matching static bounds.
11102 -- Protect call to Matching_Static_Array_Bounds to avoid costly
11103 -- operation if not needed.
11110 then
11111 Check_SPARK_05_Restriction
11115 -- In formal mode, the operand of an ancestor type conversion must be an
11116 -- object (not an expression).
11124 then
11130 -- Note: we do the Eval_Type_Conversion call before applying the
11131 -- required checks for a subtype conversion. This is important, since
11132 -- both are prepared under certain circumstances to change the type
11133 -- conversion to a constraint error node, but in the case of
11134 -- Eval_Type_Conversion this may reflect an illegality in the static
11135 -- case, and we would miss the illegality (getting only a warning
11136 -- message), if we applied the type conversion checks first.
11140 -- Even when evaluation is not possible, we may be able to simplify the
11141 -- conversion or its expression. This needs to be done before applying
11142 -- checks, since otherwise the checks may use the original expression
11143 -- and defeat the simplifications. This is specifically the case for
11144 -- elimination of the floating-point Truncation attribute in
11145 -- float-to-int conversions.
11149 -- If after evaluation we still have a type conversion, then we may need
11150 -- to apply checks required for a subtype conversion.
11152 -- Skip these type conversion checks if universal fixed operands
11153 -- operands involved, since range checks are handled separately for
11154 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
11160 then
11164 -- Issue warning for conversion of simple object to its own type. We
11165 -- have to test the original nodes, since they may have been rewritten
11166 -- by various optimizations.
11170 -- Here we test for a redundant conversion if the warning mode is
11171 -- active (and was not locally reset), and we have a type conversion
11172 -- from source not appearing in a generic instance.
11174 if Test_Redundant
11177 and then not In_Instance
11178 then
11182 -- If the node is part of a larger expression, the Target_Type
11183 -- may not be the original type of the node if the context is a
11184 -- condition. Recover original type to see if conversion is needed.
11188 then
11192 -- If we have an entity name, then give the warning if the entity
11193 -- is the right type, or if it is a loop parameter covered by the
11194 -- original type (that's needed because loop parameters have an
11195 -- odd subtype coming from the bounds).
11198 and then
11200 or else
11204 -- If not an entity, then type of expression must match
11207 then
11208 -- One more check, do not give warning if the analyzed conversion
11209 -- has an expression with non-static bounds, and the bounds of the
11210 -- target are static. This avoids junk warnings in cases where the
11211 -- conversion is necessary to establish staticness, for example in
11212 -- a case statement.
11216 then
11219 -- Finally, if this type conversion occurs in a context requiring
11220 -- a prefix, and the expression is a qualified expression then the
11221 -- type conversion is not redundant, since a qualified expression
11222 -- is not a prefix, whereas a type conversion is. For example, "X
11223 -- := T'(Funx(...)).Y;" is illegal because a selected component
11224 -- requires a prefix, but a type conversion makes it legal: "X :=
11225 -- T(T'(Funx(...))).Y;"
11227 -- In Ada 2012, a qualified expression is a name, so this idiom is
11228 -- no longer needed, but we still suppress the warning because it
11229 -- seems unfriendly for warnings to pop up when you switch to the
11230 -- newer language version.
11234 N_Indexed_Component,
11235 N_Selected_Component,
11236 N_Slice,
11237 N_Explicit_Dereference)
11238 then
11241 -- Never warn on conversion to Long_Long_Integer'Base since
11242 -- that is most likely an artifact of the extended overflow
11243 -- checking and comes from complex expanded code.
11248 -- Here we give the redundant conversion warning. If it is an
11249 -- entity, give the name of the entity in the message. If not,
11250 -- just mention the expression.
11252 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11254 else
11257 Error_Msg_NE -- CODEFIX
11260 else
11261 Error_Msg_NE
11269 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11270 -- No need to perform any interface conversion if the type of the
11271 -- expression coincides with the target type.
11274 and then Expander_Active
11276 then
11277 declare
11281 begin
11282 -- If the type of the operand is a limited view, use nonlimited
11283 -- view when available. If it is a class-wide type, recover the
11284 -- class-wide type of the nonlimited view.
11288 then
11304 -- Conversion from interface type
11308 -- Ada 2005 (AI-217): Handle entities from limited views
11312 Error_Msg_NE -- CODEFIX
11315 Error_Msg_N
11317 N);
11320 and then not
11323 then
11325 Error_Msg_NE -- CODEFIX
11328 Error_Msg_N
11330 N);
11332 else
11336 -- Conversion to interface type
11340 -- Handle subtypes
11347 or else Interface_Present_In_Ancestor
11350 then
11352 else
11355 Error_Msg_N
11363 -- Ada 2012: once the type conversion is resolved, check whether the
11364 -- operand statisfies the static predicate of the target type.
11370 -- If at this stage we have a real to integer conversion, make sure that
11371 -- the Do_Range_Check flag is set, because such conversions in general
11372 -- need a range check. We only need this if expansion is off.
11373 -- In GNATprove mode, we only do that when converting from fixed-point
11374 -- (as floating-point to integer conversions are now handled in
11375 -- GNATprove mode).
11378 and then not Expander_Active
11383 then
11387 -- Generating C code a type conversion of an access to constrained
11388 -- array type to access to unconstrained array type involves building
11389 -- a fat pointer which in general cannot be generated on the fly. We
11390 -- remove side effects in order to store the result of the conversion
11391 -- into a temporary.
11393 if Modify_Tree_For_C
11400 then
11405 ----------------------
11406 -- Resolve_Unary_Op --
11407 ----------------------
11416 begin
11419 Check_SPARK_05_Restriction
11423 -- Deal with intrinsic unary operators
11429 then
11434 -- Deal with universal cases
11437 or else
11439 then
11446 -- Generate warning for expressions like abs (x mod 2)
11448 if Warn_On_Redundant_Constructs
11450 then
11454 Error_Msg_N -- CODEFIX
11459 -- Deal with reference generation
11466 -- Set overflow checking bit. Much cleverer code needed here eventually
11467 -- and perhaps the Resolve routines should be separated for the various
11468 -- arithmetic operations, since they will need different processing ???
11476 -- Generate warning for expressions like -5 mod 3 for integers. No need
11477 -- to worry in the floating-point case, since parens do not affect the
11478 -- result so there is no point in giving in a warning.
11480 declare
11489 begin
11490 if Warn_On_Questionable_Missing_Parens
11494 then
11497 -- We are looking for cases where the right operand is not
11498 -- parenthesized, and is a binary operator, multiply, divide, or
11499 -- mod. These are the cases where the grouping can affect results.
11503 then
11504 -- For mod, we always give the warning, since the value is
11505 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11506 -- -(5 mod 315)). But for the other cases, the only concern is
11507 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11508 -- overflows, but (-2) * 64 does not). So we try to give the
11509 -- message only when overflow is possible.
11513 then
11518 else
11524 else
11528 -- Note that the test below is deliberately excluding the
11529 -- largest negative number, since that is a potentially
11530 -- troublesome case (e.g. -2 * x, where the result is the
11531 -- largest negative integer has an overflow with 2 * x).
11538 -- For the multiplication case, the only case we have to worry
11539 -- about is when (-a)*b is exactly the largest negative number
11540 -- so that -(a*b) can cause overflow. This can only happen if
11541 -- a is a power of 2, and more generally if any operand is a
11542 -- constant that is not a power of 2, then the parentheses
11543 -- cannot affect whether overflow occurs. We only bother to
11544 -- test the left most operand
11546 -- Loop looking at left operands for one that has known value
11553 -- Operand value of 0 or 1 skips warning
11558 -- Otherwise check power of 2, if power of 2, warn, if
11559 -- anything else, skip warning.
11561 else
11565 else
11574 -- Keep looking at left operands
11579 -- For rem or "/" we can only have a problematic situation
11580 -- if the divisor has a value of minus one or one. Otherwise
11581 -- overflow is impossible (divisor > 1) or we have a case of
11582 -- division by zero in any case.
11587 then
11591 -- If we fall through warning should be issued
11593 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11595 Error_Msg_N
11602 ----------------------------------
11603 -- Resolve_Unchecked_Expression --
11604 ----------------------------------
11606 procedure Resolve_Unchecked_Expression
11609 is
11610 begin
11615 ---------------------------------------
11616 -- Resolve_Unchecked_Type_Conversion --
11617 ---------------------------------------
11619 procedure Resolve_Unchecked_Type_Conversion
11622 is
11628 begin
11629 -- Resolve operand using its own type
11633 -- In an inlined context, the unchecked conversion may be applied
11634 -- to a literal, in which case its type is the type of the context.
11635 -- (In other contexts conversions cannot apply to literals).
11637 if In_Inlined_Body
11641 then
11649 ------------------------------
11650 -- Rewrite_Operator_As_Call --
11651 ------------------------------
11658 begin
11665 New_N :=
11676 ------------------------------
11677 -- Rewrite_Renamed_Operator --
11678 ------------------------------
11680 procedure Rewrite_Renamed_Operator
11684 is
11689 begin
11690 -- Do not perform this transformation within a pre/postcondition,
11691 -- because the expression will be reanalyzed, and the transformation
11692 -- might affect the visibility of the operator, e.g. in an instance.
11693 -- Note that fully analyzed and expanded pre/postconditions appear as
11694 -- pragma Check equivalents.
11700 -- Likewise when an expression function is being preanalyzed, since the
11701 -- expression will be reanalyzed as part of the generated body.
11704 declare
11706 begin
11709 N_Expression_Function
11710 then
11716 -- Rewrite the operator node using the real operator, not its renaming.
11717 -- Exclude user-defined intrinsic operations of the same name, which are
11718 -- treated separately and rewritten as calls.
11727 -- Indicate that both the original entity and its renaming are
11728 -- referenced at this point.
11739 -- If the context type is private, add the appropriate conversions so
11740 -- that the operator is applied to the full view. This is done in the
11741 -- routines that resolve intrinsic operators.
11745 when N_Op_Add
11746 | N_Op_Divide
11747 | N_Op_Expon
11748 | N_Op_Mod
11749 | N_Op_Multiply
11750 | N_Op_Rem
11751 | N_Op_Subtract
11752 =>
11755 when N_Op_Abs
11756 | N_Op_Minus
11757 | N_Op_Plus
11758 =>
11768 -- Operator renames a user-defined operator of the same name. Use the
11769 -- original operator in the node, which is the one Gigi knows about.
11776 -----------------------
11777 -- Set_Slice_Subtype --
11778 -----------------------
11780 -- Build an implicit subtype declaration to represent the type delivered by
11781 -- the slice. This is an abbreviated version of an array subtype. We define
11782 -- an index subtype for the slice, using either the subtype name or the
11783 -- discrete range of the slice. To be consistent with index usage elsewhere
11784 -- we create a list header to hold the single index. This list is not
11785 -- otherwise attached to the syntax tree.
11796 begin
11802 else
11803 -- We force the evaluation of a range. This is definitely needed in
11804 -- the renamed case, and seems safer to do unconditionally. Note in
11805 -- any case that since we will create and insert an Itype referring
11806 -- to this range, we must make sure any side effect removal actions
11807 -- are inserted before the Itype definition.
11813 -- If the discrete range is given by a subtype indication, the
11814 -- type of the slice is the base of the subtype mark.
11817 declare
11819 begin
11828 -- Take a new copy of Drange (where bounds have been rewritten to
11829 -- reference side-effect-free names). Using a separate tree ensures
11830 -- that further expansion (e.g. while rewriting a slice assignment
11831 -- into a FOR loop) does not attempt to remove side effects on the
11832 -- bounds again (which would cause the bounds in the index subtype
11833 -- definition to refer to temporaries before they are defined) (the
11834 -- reason is that some names are considered side effect free here
11835 -- for the subtype, but not in the context of a loop iteration
11836 -- scheme).
11857 -- The Etype of the existing Slice node is reset to this slice subtype.
11858 -- Its bounds are obtained from its first index.
11862 -- For bit-packed slice subtypes, freeze immediately (except in the case
11863 -- of being in a "spec expression" where we never freeze when we first
11864 -- see the expression).
11869 -- For all other cases insert an itype reference in the slice's actions
11870 -- so that the itype is frozen at the proper place in the tree (i.e. at
11871 -- the point where actions for the slice are analyzed). Note that this
11872 -- is different from freezing the itype immediately, which might be
11873 -- premature (e.g. if the slice is within a transient scope). This needs
11874 -- to be done only if expansion is enabled.
11881 --------------------------------
11882 -- Set_String_Literal_Subtype --
11883 --------------------------------
11891 begin
11903 -- The low bound is set from the low bound of the corresponding index
11904 -- type. Note that we do not store the high bound in the string literal
11905 -- subtype, but it can be deduced if necessary from the length and the
11906 -- low bound.
11911 -- If the lower bound is not static we create a range for the string
11912 -- literal, using the index type and the known length of the literal.
11913 -- The index type is not necessarily Positive, so the upper bound is
11914 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11916 else
11917 declare
11923 Prefix =>
11927 Left_Opnd =>
11930 Prefix =>
11932 Expressions =>
11934 Right_Opnd =>
11943 begin
11945 Set_String_Literal_Low_Bound
11948 else
11949 -- If the index type is an enumeration type, build bounds
11950 -- expression with attributes.
11952 Set_String_Literal_Low_Bound
11956 Prefix =>
11963 -- Build bona fide subtype for the string, and wrap it in an
11964 -- unchecked conversion, because the back end expects the
11965 -- String_Literal_Subtype to have a static lower bound.
11967 Index_Subtype :=
11974 -- In this context, the Index_Type may already have a constraint,
11975 -- so use common base type on string subtype. The base type may
11976 -- be used when generating attributes of the string, for example
11977 -- in the context of a slice assignment.
12002 ------------------------------
12003 -- Simplify_Type_Conversion --
12004 ------------------------------
12007 begin
12009 declare
12014 begin
12015 -- Special processing if the conversion is the expression of a
12016 -- Rounding or Truncation attribute reference. In this case we
12017 -- replace:
12019 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
12021 -- by
12023 -- ityp (x)
12025 -- with the Float_Truncate flag set to False or True respectively,
12026 -- which is more efficient.
12029 and then
12035 Name_Truncation)
12036 then
12037 declare
12040 begin
12050 -----------------------------
12051 -- Unique_Fixed_Point_Type --
12052 -----------------------------
12056 -- Give error messages for true ambiguity. Messages are posted on node
12057 -- N, and entities T1, T2 are the possible interpretations.
12059 -----------------------
12060 -- Fixed_Point_Error --
12061 -----------------------
12064 begin
12070 -- Local variables
12078 -- Start of processing for Unique_Fixed_Point_Type
12080 begin
12081 -- The operations on Duration are visible, so Duration is always a
12082 -- possible interpretation.
12086 -- Look for fixed-point types in enclosing scopes
12095 then
12099 else
12110 -- Look for visible fixed type declarations in the context
12121 then
12125 else
12140 else
12141 -- When the context is a type conversion, issue the warning on the
12142 -- expression of the conversion because it is the actual operation.
12146 else
12150 Error_Msg_NE
12157 ----------------------
12158 -- Valid_Conversion --
12159 ----------------------
12161 function Valid_Conversion
12166 is
12171 function Conversion_Check
12174 -- Little routine to post Msg if Valid is False, returns Valid value
12177 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
12179 procedure Conversion_Error_NE
12183 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
12186 -- Return True if expression is within an instance but is not in one of
12187 -- the actuals of the instantiation. Type conversions within an instance
12188 -- are not rechecked because type visbility may lead to spurious errors,
12189 -- but conversions in an actual for a formal object must be checked.
12191 function Valid_Tagged_Conversion
12194 -- Specifically test for validity of tagged conversions
12197 -- Check index and component conformance, and accessibility levels if
12198 -- the component types are anonymous access types (Ada 2005).
12200 ----------------------
12201 -- Conversion_Check --
12202 ----------------------
12204 function Conversion_Check
12207 is
12208 begin
12209 if not Valid
12211 -- A generic unit has already been analyzed and we have verified
12212 -- that a particular conversion is OK in that context. Since the
12213 -- instance is reanalyzed without relying on the relationships
12214 -- established during the analysis of the generic, it is possible
12215 -- to end up with inconsistent views of private types. Do not emit
12216 -- the error message in such cases. The rest of the machinery in
12217 -- Valid_Conversion still ensures the proper compatibility of
12218 -- target and operand types.
12220 and then not In_Instance_Code
12221 then
12228 ------------------------
12229 -- Conversion_Error_N --
12230 ------------------------
12233 begin
12239 -------------------------
12240 -- Conversion_Error_NE --
12241 -------------------------
12243 procedure Conversion_Error_NE
12247 is
12248 begin
12254 ----------------------
12255 -- In_Instance_Code --
12256 ----------------------
12261 begin
12265 else
12269 -- The expression is part of an actual object if it appears in
12270 -- the generated object declaration in the instance.
12274 then
12277 else
12278 exit when
12287 -- Otherwise the expression appears within the instantiated unit
12293 ----------------------------
12294 -- Valid_Array_Conversion --
12295 ----------------------------
12312 begin
12313 -- Error if wrong number of dimensions
12315 if
12317 then
12318 Conversion_Error_N
12322 -- Number of dimensions matches
12324 else
12325 -- Loop through indexes of the two arrays
12333 -- Error if index types are incompatible
12339 then
12340 Conversion_Error_N
12342 Operand);
12350 -- If component types have same base type, all set
12355 -- Here if base types of components are not the same. The only
12356 -- time this is allowed is if we have anonymous access types.
12358 -- The conversion of arrays of anonymous access types can lead
12359 -- to dangling pointers. AI-392 formalizes the accessibility
12360 -- checks that must be applied to such conversions to prevent
12361 -- out-of-scope references.
12363 elsif Ekind_In
12365 E_Anonymous_Access_Subprogram_Type)
12367 and then
12369 then
12372 then
12375 Conversion_Error_N
12385 -- Conversion not allowed because of accessibility levels
12387 else
12388 Conversion_Error_N
12394 else
12398 -- All other cases where component base types do not match
12400 else
12401 Conversion_Error_N
12403 Operand);
12407 -- Check that component subtypes statically match. For numeric
12408 -- types this means that both must be either constrained or
12409 -- unconstrained. For enumeration types the bounds must match.
12410 -- All of this is checked in Subtypes_Statically_Match.
12412 if not Subtypes_Statically_Match
12414 then
12415 Conversion_Error_N
12424 -----------------------------
12425 -- Valid_Tagged_Conversion --
12426 -----------------------------
12428 function Valid_Tagged_Conversion
12431 is
12432 begin
12433 -- Upward conversions are allowed (RM 4.6(22))
12437 then
12440 -- Downward conversion are allowed if the operand is class-wide
12441 -- (RM 4.6(23)).
12445 then
12450 then
12451 return
12455 -- Ada 2005 (AI-251): The conversion to/from interface types is
12456 -- always valid. The types involved may be class-wide (sub)types.
12460 then
12463 -- If the operand is a class-wide type obtained through a limited_
12464 -- with clause, and the context includes the nonlimited view, use
12465 -- it to determine whether the conversion is legal.
12471 then
12476 then
12479 else
12480 Conversion_Error_NE
12487 -- Start of processing for Valid_Conversion
12489 begin
12493 declare
12501 begin
12502 -- Remove procedure calls, which syntactically cannot appear in
12503 -- this context, but which cannot be removed by type checking,
12504 -- because the context does not impose a type.
12506 -- The node may be labelled overloaded, but still contain only one
12507 -- interpretation because others were discarded earlier. If this
12508 -- is the case, retain the single interpretation if legal.
12516 then
12517 -- More than one candidate interpretation is available
12525 -- When compiling for a system where Address is of a visible
12526 -- integer type, spurious ambiguities can be produced when
12527 -- arithmetic operations have a literal operand and return
12528 -- System.Address or a descendant of it. These ambiguities
12529 -- are usually resolved by the context, but for conversions
12530 -- there is no context type and the removal of the spurious
12531 -- operations must be done explicitly here.
12533 if not Address_Is_Private
12535 then
12560 Conversion_Error_N
12563 -- If the interpretation involves a standard operator, use
12564 -- the location of the type, which may be user-defined.
12568 else
12572 Conversion_Error_N -- CODEFIX
12577 else
12581 Conversion_Error_N -- CODEFIX
12593 -- Deal with conversion of integer type to address if the pragma
12594 -- Allow_Integer_Address is in effect. We convert the conversion to
12595 -- an unchecked conversion in this case and we are all done.
12603 -- If we are within a child unit, check whether the type of the
12604 -- expression has an ancestor in a parent unit, in which case it
12605 -- belongs to its derivation class even if the ancestor is private.
12606 -- See RM 7.3.1 (5.2/3).
12610 -- Numeric types
12614 -- A universal fixed expression can be converted to any numeric type
12619 -- Also no need to check when in an instance or inlined body, because
12620 -- the legality has been established when the template was analyzed.
12621 -- Furthermore, numeric conversions may occur where only a private
12622 -- view of the operand type is visible at the instantiation point.
12623 -- This results in a spurious error if we check that the operand type
12624 -- is a numeric type.
12626 -- Note: in a previous version of this unit, the following tests were
12627 -- applied only for generated code (Comes_From_Source set to False),
12628 -- but in fact the test is required for source code as well, since
12629 -- this situation can arise in source code.
12634 -- Otherwise we need the conversion check
12636 else
12637 return Conversion_Check
12639 or else
12645 -- Array types
12651 then
12652 Conversion_Error_N
12656 else
12660 -- Ada 2005 (AI-251): Internally generated conversions of access to
12661 -- interface types added to force the displacement of the pointer to
12662 -- reference the corresponding dispatch table.
12667 then
12670 -- Ada 2005 (AI-251): Anonymous access types where target references an
12671 -- interface type.
12675 E_Anonymous_Access_Type)
12677 then
12678 -- Check the static accessibility rule of 4.6(17). Note that the
12679 -- check is not enforced when within an instance body, since the
12680 -- RM requires such cases to be caught at run time.
12682 -- If the operand is a rewriting of an allocator no check is needed
12683 -- because there are no accessibility issues.
12691 then
12692 -- In an instance, this is a run-time check, but one we know
12693 -- will fail, so generate an appropriate warning. The raise
12694 -- will be generated by Expand_N_Type_Conversion.
12698 Conversion_Error_N
12700 Operand);
12703 else
12704 Conversion_Error_N
12706 Operand);
12710 -- Special accessibility checks are needed in the case of access
12711 -- discriminants declared for a limited type.
12715 then
12716 -- When the operand is a selected access discriminant the check
12717 -- needs to be made against the level of the object denoted by
12718 -- the prefix of the selected name (Object_Access_Level handles
12719 -- checking the prefix of the operand for this case).
12724 then
12725 -- In an instance, this is a run-time check, but one we know
12726 -- will fail, so generate an appropriate warning. The raise
12727 -- will be generated by Expand_N_Type_Conversion.
12731 Conversion_Error_N
12736 -- Real error if not in instance body
12738 else
12739 Conversion_Error_N
12746 -- The case of a reference to an access discriminant from
12747 -- within a limited type declaration (which will appear as
12748 -- a discriminal) is always illegal because the level of the
12749 -- discriminant is considered to be deeper than any (nameable)
12750 -- access type.
12754 and then
12757 then
12758 Conversion_Error_N
12760 Operand);
12768 -- General and anonymous access types
12771 E_Anonymous_Access_Type)
12772 and then
12773 Conversion_Check
12775 and then not
12777 E_Access_Protected_Subprogram_Type),
12779 then
12782 then
12783 Conversion_Error_N
12788 -- Check the static accessibility rule of 4.6(17). Note that the
12789 -- check is not enforced when within an instance body, since the RM
12790 -- requires such cases to be caught at run time.
12795 N_Object_Declaration
12796 then
12797 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12798 -- conversions from an anonymous access type to a named general
12799 -- access type. Such conversions are not allowed in the case of
12800 -- access parameters and stand-alone objects of an anonymous
12801 -- access type. The implicit conversion case is recognized by
12802 -- testing that Comes_From_Source is False and that it's been
12803 -- rewritten. The Comes_From_Source test isn't sufficient because
12804 -- nodes in inlined calls to predefined library routines can have
12805 -- Comes_From_Source set to False. (Is there a better way to test
12806 -- for implicit conversions???)
12813 then
12816 -- Implicit conversions aren't allowed for objects of an
12817 -- anonymous access type, since such objects have nonstatic
12818 -- levels in Ada 2012.
12821 N_Object_Declaration
12822 then
12823 Conversion_Error_N
12828 -- Implicit conversions aren't allowed for anonymous access
12829 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12830 -- is done to exclude anonymous access results.
12834 N_Function_Specification,
12835 N_Procedure_Specification)
12836 then
12837 Conversion_Error_N
12842 -- This is a case where there's an enclosing object whose
12843 -- to which the "statically deeper than" relationship does
12844 -- not apply (such as an access discriminant selected from
12845 -- a dereference of an access parameter).
12849 then
12850 Conversion_Error_N
12855 -- In other cases, the level of the operand's type must be
12856 -- statically less deep than that of the target type, else
12857 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12861 then
12862 Conversion_Error_N
12871 then
12872 -- In an instance, this is a run-time check, but one we know
12873 -- will fail, so generate an appropriate warning. The raise
12874 -- will be generated by Expand_N_Type_Conversion.
12878 Conversion_Error_N
12880 Operand);
12883 -- If not in an instance body, this is a real error
12885 else
12886 -- Avoid generation of spurious error message
12889 Conversion_Error_N
12891 Operand);
12897 -- Special accessibility checks are needed in the case of access
12898 -- discriminants declared for a limited type.
12902 then
12903 -- When the operand is a selected access discriminant the check
12904 -- needs to be made against the level of the object denoted by
12905 -- the prefix of the selected name (Object_Access_Level handles
12906 -- checking the prefix of the operand for this case).
12911 then
12912 -- In an instance, this is a run-time check, but one we know
12913 -- will fail, so generate an appropriate warning. The raise
12914 -- will be generated by Expand_N_Type_Conversion.
12918 Conversion_Error_N
12923 -- If not in an instance body, this is a real error
12925 else
12926 Conversion_Error_N
12933 -- The case of a reference to an access discriminant from
12934 -- within a limited type declaration (which will appear as
12935 -- a discriminal) is always illegal because the level of the
12936 -- discriminant is considered to be deeper than any (nameable)
12937 -- access type.
12940 and then
12943 then
12944 Conversion_Error_N
12946 Operand);
12952 -- In the presence of limited_with clauses we have to use nonlimited
12953 -- views, if available.
12957 -- Helper function to handle limited views
12959 --------------------------
12960 -- Full_Designated_Type --
12961 --------------------------
12966 begin
12967 -- Handle the limited view of a type
12971 then
12973 else
12978 -- Local Declarations
12986 -- Start of processing for Check_Limited
12988 begin
12992 else
12994 Conversion_Error_NE
12999 -- Ada 2005 AI-384: legality rule is symmetric in both
13000 -- designated types. The conversion is legal (with possible
13001 -- constraint check) if either designated type is
13002 -- unconstrained.
13005 or else
13007 and then
13010 then
13011 -- Special case, if Value_Size has been used to make the
13012 -- sizes different, the conversion is not allowed even
13013 -- though the subtypes statically match.
13018 then
13019 Conversion_Error_NE
13022 Conversion_Error_NE
13027 -- Normal case where conversion is allowed
13029 else
13033 else
13034 Error_Msg_NE
13042 -- Access to subprogram types. If the operand is an access parameter,
13043 -- the type has a deeper accessibility that any master, and cannot be
13044 -- assigned. We must make an exception if the conversion is part of an
13045 -- assignment and the target is the return object of an extended return
13046 -- statement, because in that case the accessibility check takes place
13047 -- after the return.
13051 -- Note: this test of Opnd_Type is there to prevent entering this
13052 -- branch in the case of a remote access to subprogram type, which
13053 -- is internally represented as an E_Record_Type.
13056 then
13060 and then
13064 then
13065 Conversion_Error_N
13067 Operand);
13068 Conversion_Error_N
13071 Operand);
13073 Error_Msg_NE
13078 -- Check that the designated types are subtype conformant
13084 -- Check the static accessibility rule of 4.6(20)
13088 then
13089 Conversion_Error_N
13091 Operand);
13093 -- Check that if the operand type is declared in a generic body,
13094 -- then the target type must be declared within that same body
13095 -- (enforces last sentence of 4.6(20)).
13098 declare
13104 begin
13111 Conversion_Error_N
13120 -- Remote access to subprogram types
13124 then
13125 -- It is valid to convert from one RAS type to another provided
13126 -- that their specification statically match.
13128 -- Note: at this point, remote access to subprogram types have been
13129 -- expanded to their E_Record_Type representation, and we need to
13130 -- go back to the original access type definition using the
13131 -- Corresponding_Remote_Type attribute in order to check that the
13132 -- designated profiles match.
13137 Check_Subtype_Conformant
13140 Old_Id =>
13142 Err_Loc =>
13143 N);
13146 -- If it was legal in the generic, it's legal in the instance
13151 -- If both are tagged types, check legality of view conversions
13154 and then
13156 then
13159 -- Types derived from the same root type are convertible
13164 -- In an instance or an inlined body, there may be inconsistent views of
13165 -- the same type, or of types derived from a common root.
13168 and then
13171 then
13174 -- Special check for common access type error case
13178 then
13180 Conversion_Error_NE -- CODEFIX
13184 -- Here we have a real conversion error
13186 else
13187 -- Check for missing regular with_clause when only a limited view of
13188 -- target is available.
13191 Conversion_Error_NE
13194 Conversion_Error_NE
13199 and then In_Package_Body
13200 then
13201 Conversion_Error_NE
13203 Conversion_Error_NE
13207 else
13208 Conversion_Error_NE