| blob | b45e917a308b41cab86441e29bbf85a38076200f |
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 begin
1687 -- Normally, we suppress all checks for this preanalysis. There is no
1688 -- point in processing them now, since they will be applied properly
1689 -- and in the proper location when the default expressions reanalyzed
1690 -- and reexpanded later on. We will also have more information at that
1691 -- point for possible suppression of individual checks.
1693 -- However, in SPARK mode, most expansion is suppressed, and this
1694 -- later reanalysis and reexpansion may not occur. SPARK mode does
1695 -- require the setting of checking flags for proof purposes, so we
1696 -- do the SPARK preanalysis without suppressing checks.
1698 -- This special handling for SPARK mode is required for example in the
1699 -- case of Ada 2012 constructs such as quantified expressions, which are
1700 -- expanded in two separate steps.
1704 else
1708 Expander_Mode_Restore;
1713 ----------------------------
1714 -- Preanalyze_And_Resolve --
1715 ----------------------------
1718 begin
1722 -- Version without context type
1727 begin
1734 Expander_Mode_Restore;
1738 ------------------------------------------
1739 -- Preanalyze_With_Freezing_And_Resolve --
1740 ------------------------------------------
1742 procedure Preanalyze_With_Freezing_And_Resolve
1745 is
1746 begin
1750 ----------------------------------
1751 -- Replace_Actual_Discriminants --
1752 ----------------------------------
1759 -- Comment needed???
1761 -------------------
1762 -- Process_Discr --
1763 -------------------
1768 begin
1774 then
1790 -- Start of processing for Replace_Actual_Discriminants
1792 begin
1796 -- Allow the replacement of concurrent discriminants in GNATprove even
1797 -- though this is a light expansion activity. Note that generic units
1798 -- are not modified.
1803 else
1819 -------------
1820 -- Resolve --
1821 -------------
1837 -- Determine whether a node comes from a predefined library unit or
1838 -- Standard.
1841 -- Try and fix up a literal so that it matches its expected type. New
1842 -- literals are manufactured if necessary to avoid cascaded errors.
1845 -- Additional diagnostics when an ambiguous call has an ambiguous
1846 -- argument (typically a controlling actual).
1849 -- Called when attempt at resolving current expression fails
1851 ------------------------------------
1852 -- Comes_From_Predefined_Lib_Unit --
1853 -------------------------------------
1856 begin
1857 return
1861 --------------------
1862 -- Patch_Up_Value --
1863 --------------------
1866 begin
1883 then
1888 Char_Literal_Value =>
1904 -------------------------------
1905 -- Report_Ambiguous_Argument --
1906 -------------------------------
1913 begin
1917 then
1920 -- Could use comments on what is going on here???
1928 else
1937 -----------------------
1938 -- Resolution_Failed --
1939 -----------------------
1942 begin
1945 -- Set the type to the desired one to minimize cascaded errors. Note
1946 -- that this is an approximation and does not work in all cases.
1953 -- The caller will return without calling the expander, so we need
1954 -- to set the analyzed flag. Note that it is fine to set Analyzed
1955 -- to True even if we are in the middle of a shallow analysis,
1956 -- (see the spec of sem for more details) since this is an error
1957 -- situation anyway, and there is no point in repeating the
1958 -- analysis later (indeed it won't work to repeat it later, since
1959 -- we haven't got a clear resolution of which entity is being
1960 -- referenced.)
1966 -- Start of processing for Resolve
1968 begin
1973 -- Access attribute on remote subprogram cannot be used for a non-remote
1974 -- access-to-subprogram type.
1978 Name_Unrestricted_Access,
1979 Name_Unchecked_Access)
1985 then
1986 Error_Msg_N
1992 -- If the context is a Remote_Access_To_Subprogram, access attributes
1993 -- must be resolved with the corresponding fat pointer. There is no need
1994 -- to check for the attribute name since the return type of an
1995 -- attribute is never a remote type.
2000 then
2001 declare
2009 begin
2010 -- Check that Typ is a remote access-to-subprogram type
2014 -- Prefix (N) must statically denote a remote subprogram
2015 -- declared in a package specification.
2019 Attr = Attribute_Unrestricted_Access
2020 then
2035 or else
2037 then
2039 Error_Msg_N
2041 N);
2044 -- If we are generating code in distributed mode, perform
2045 -- semantic checks against corresponding remote entities.
2047 if Expander_Active
2049 then
2050 Check_Subtype_Conformant
2052 Old_Id => Designated_Type
2078 then
2083 -- Return if already analyzed
2090 -- Any case of Any_Type as the Etype value means that we had a
2091 -- previous error.
2100 -- The resolution of an Expression_With_Actions is determined by
2101 -- its Expression.
2109 -- If not overloaded, then we know the type, and all that needs doing
2110 -- is to check that this type is compatible with the context.
2116 -- In the overloaded case, we must select the interpretation that
2117 -- is compatible with the context (i.e. the type passed to Resolve)
2119 else
2120 -- Loop through possible interpretations
2129 -- We are only interested in interpretations that are compatible
2130 -- with the expected type, any other interpretations are ignored.
2135 Write_Eol;
2138 else
2139 -- Skip the current interpretation if it is disabled by an
2140 -- abstract operator. This action is performed only when the
2141 -- type against which we are resolving is the same as the
2142 -- type of the interpretation.
2149 then
2157 -- First matching interpretation
2165 -- Matching interpretation that is not the first, maybe an
2166 -- error, but there are some cases where preference rules are
2167 -- used to choose between the two possibilities. These and
2168 -- some more obscure cases are handled in Disambiguate.
2170 else
2171 -- If the current statement is part of a predefined library
2172 -- unit, then all interpretations which come from user level
2173 -- packages should not be considered. Check previous and
2174 -- current one.
2182 -- Previous interpretation must be discarded
2192 -- Otherwise apply further disambiguation steps
2197 -- Disambiguation has succeeded. Skip the remaining
2198 -- interpretations.
2208 else
2209 -- Before we issue an ambiguity complaint, check for the
2210 -- case of a subprogram call where at least one of the
2211 -- arguments is Any_Type, and if so suppress the message,
2212 -- since it is a cascaded error. This can also happen for
2213 -- a generalized indexing operation.
2218 then
2219 declare
2223 begin
2239 Write_Eol;
2252 then
2257 then
2261 -- Not that special case, so issue message using the flag
2262 -- Ambiguous to control printing of the header message
2263 -- only at the start of an ambiguous set.
2268 then
2269 Error_Msg_N
2272 else
2273 Error_Msg_NE -- CODEFIX
2281 Error_Msg_N
2283 else
2284 Error_Msg_N -- CODEFIX
2290 then
2291 Report_Ambiguous_Argument;
2297 -- By default, the error message refers to the candidate
2298 -- interpretation. But if it is a predefined operator, it
2299 -- is implicitly declared at the declaration of the type
2300 -- of the operand. Recover the sloc of that declaration
2301 -- for the error message.
2307 Standard_Standard
2308 then
2313 then
2321 Standard_Standard
2322 then
2327 then
2331 -- If this is an indirect call, use the subprogram_type
2332 -- in the message, to have a meaningful location. Also
2333 -- indicate if this is an inherited operation, created
2334 -- by a type declaration.
2339 then
2341 Error_Msg_Sloc :=
2343 else
2350 then
2351 -- Special-case the message for universal_fixed
2352 -- operators, which are not declared with the type
2353 -- of the operand, but appear forever in Standard.
2357 then
2358 Error_Msg_N
2361 else
2362 Error_Msg_N
2366 elsif
2368 then
2369 Error_Msg_N
2371 else
2372 Error_Msg_N -- CODEFIX
2379 -- We have a matching interpretation, Expr_Type is the type
2380 -- from this interpretation, and Seen is the entity.
2382 -- For an operator, just set the entity name. The type will be
2383 -- set by the specific operator resolution routine.
2390 N_Character_Literal,
2391 N_Delta_Aggregate,
2392 N_If_Expression)
2393 then
2396 -- AI05-0139-2: Expression is overloaded because type has
2397 -- implicit dereference. If type matches context, no implicit
2398 -- dereference is involved. If the expression is an entity,
2399 -- generate a reference to it, as this is not done for an
2400 -- overloaded construct during analysis.
2416 then
2417 -- If the node is a general indexing, the dereference is
2418 -- is inserted when resolving the rewritten form, else
2419 -- insert it now.
2423 then
2427 -- For an explicit dereference, attribute reference, range,
2428 -- short-circuit form (which is not an operator node), or call
2429 -- with a name that is an explicit dereference, there is
2430 -- nothing to be done at this point.
2433 N_And_Then,
2434 N_Explicit_Dereference,
2435 N_Identifier,
2436 N_Indexed_Component,
2437 N_Or_Else,
2438 N_Range,
2439 N_Selected_Component,
2440 N_Slice)
2442 then
2445 -- For procedure or function calls, set the type of the name,
2446 -- and also the entity pointer for the prefix.
2450 then
2457 then
2462 -- For all other cases, just set the type of the Name
2464 else
2472 -- Move to next interpretation
2480 -- At this stage Found indicates whether or not an acceptable
2481 -- interpretation exists. If not, then we have an error, except that if
2482 -- the context is Any_Type as a result of some other error, then we
2483 -- suppress the error report.
2488 -- If type we are looking for is Void, then this is the procedure
2489 -- call case, and the error is simply that what we gave is not a
2490 -- procedure name (we think of procedure calls as expressions with
2491 -- types internally, but the user doesn't think of them this way).
2495 -- Special case message if function used as a procedure
2500 then
2501 Error_Msg_NE
2504 Error_Msg_N
2508 -- Otherwise give general message (not clear what cases this
2509 -- covers, but no harm in providing for them).
2511 else
2517 -- Otherwise we do have a subexpression with the wrong type
2519 -- Check for the case of an allocator which uses an access type
2520 -- instead of the designated type. This is a common error and we
2521 -- specialize the message, posting an error on the operand of the
2522 -- allocator, complaining that we expected the designated type of
2523 -- the allocator.
2529 then
2533 -- Check for view mismatch on Null in instances, for which the
2534 -- view-swapping mechanism has no identifier.
2540 then
2545 -- Check for an aggregate. Sometimes we can get bogus aggregates
2546 -- from misuse of parentheses, and we are about to complain about
2547 -- the aggregate without even looking inside it.
2549 -- Instead, if we have an aggregate of type Any_Composite, then
2550 -- analyze and resolve the component fields, and then only issue
2551 -- another message if we get no errors doing this (otherwise
2552 -- assume that the errors in the aggregate caused the problem).
2556 then
2557 -- Disable expansion in any case. If there is a type mismatch
2558 -- it may be fatal to try to expand the aggregate. The flag
2559 -- would otherwise be set to false when the error is posted.
2563 declare
2565 -- Check one aggregate, and set Found to True if we have a
2566 -- definite error in any of its elements
2569 -- Check one element of aggregate and set Found to True if
2570 -- we definitely have an error in the element.
2572 ----------------
2573 -- Check_Aggr --
2574 ----------------
2579 begin
2592 -- If this is a default-initialized component, then
2593 -- there is nothing to check. The box will be
2594 -- replaced by the appropriate call during late
2595 -- expansion.
2599 then
2608 ----------------
2609 -- Check_Elmt --
2610 ----------------
2613 begin
2614 -- If we have a nested aggregate, go inside it (to
2615 -- attempt a naked analyze-resolve of the aggregate can
2616 -- cause undesirable cascaded errors). Do not resolve
2617 -- expression if it needs a type from context, as for
2618 -- integer * fixed expression.
2623 else
2628 then
2638 begin
2643 -- Looks like we have a type error, but check for special case
2644 -- of Address wanted, integer found, with the configuration pragma
2645 -- Allow_Integer_Address active. If we have this case, introduce
2646 -- an unchecked conversion to allow the integer expression to be
2647 -- treated as an Address. The reverse case of integer wanted,
2648 -- Address found, is treated in an analogous manner.
2655 -- Under relaxed RM semantics silently replace occurrences of null
2656 -- by System.Address_Null.
2664 -- That special Allow_Integer_Address check did not apply, so we
2665 -- have a real type error. If an error message was issued already,
2666 -- Found got reset to True, so if it's still False, issue standard
2667 -- Wrong_Type message.
2671 declare
2674 begin
2680 -- Protected operation: retrieve operation name
2684 else
2689 Error_Msg_NE
2695 declare
2699 begin
2706 Error_Msg_NE
2712 else
2716 else
2722 Resolution_Failed;
2725 -- Test if we have more than one interpretation for the context
2728 Resolution_Failed;
2731 -- Only one intepretation
2733 else
2734 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2735 -- the "+" on T is abstract, and the operands are of universal type,
2736 -- the above code will have (incorrectly) resolved the "+" to the
2737 -- universal one in Standard. Therefore check for this case and give
2738 -- an error. We can't do this earlier, because it would cause legal
2739 -- cases to get errors (when some other type has an abstract "+").
2745 then
2750 then
2751 Error_Msg_NE
2760 -- Here we have an acceptable interpretation for the context
2762 -- Propagate type information and normalize tree for various
2763 -- predefined operations. If the context only imposes a class of
2764 -- types, rather than a specific type, propagate the actual type
2765 -- downward.
2771 Typ = Any_Discrete
2772 then
2775 -- Any_Fixed is legal in a real context only if a specific fixed-
2776 -- point type is imposed. If Norman Cohen can be confused by this,
2777 -- it deserves a separate message.
2781 then
2788 -- A user-defined operator is transformed into a function call at
2789 -- this point, so that further processing knows that operators are
2790 -- really operators (i.e. are predefined operators). User-defined
2791 -- operators that are intrinsic are just renamings of the predefined
2792 -- ones, and need not be turned into calls either, but if they rename
2793 -- a different operator, we must transform the node accordingly.
2794 -- Instantiations of Unchecked_Conversion are intrinsic but are
2795 -- treated as functions, even if given an operator designator.
2800 then
2805 and then
2807 N_Subprogram_Renaming_Declaration
2808 then
2811 -- If the node is rewritten, it will be fully resolved in
2812 -- Rewrite_Renamed_Operator.
2821 when N_Aggregate =>
2822 Resolve_Aggregate (N, Ctx_Type);
2824 when N_Allocator =>
2825 Resolve_Allocator (N, Ctx_Type);
2827 when N_Short_Circuit =>
2828 Resolve_Short_Circuit (N, Ctx_Type);
2830 when N_Attribute_Reference =>
2831 Resolve_Attribute (N, Ctx_Type);
2833 when N_Case_Expression =>
2834 Resolve_Case_Expression (N, Ctx_Type);
2836 when N_Character_Literal =>
2837 Resolve_Character_Literal (N, Ctx_Type);
2839 when N_Delta_Aggregate =>
2840 Resolve_Delta_Aggregate (N, Ctx_Type);
2842 when N_Expanded_Name =>
2843 Resolve_Entity_Name (N, Ctx_Type);
2845 when N_Explicit_Dereference =>
2846 Resolve_Explicit_Dereference (N, Ctx_Type);
2848 when N_Expression_With_Actions =>
2849 Resolve_Expression_With_Actions (N, Ctx_Type);
2851 when N_Extension_Aggregate =>
2852 Resolve_Extension_Aggregate (N, Ctx_Type);
2854 when N_Function_Call =>
2855 Resolve_Call (N, Ctx_Type);
2857 when N_Identifier =>
2858 Resolve_Entity_Name (N, Ctx_Type);
2860 when N_If_Expression =>
2861 Resolve_If_Expression (N, Ctx_Type);
2863 when N_Indexed_Component =>
2864 Resolve_Indexed_Component (N, Ctx_Type);
2866 when N_Integer_Literal =>
2867 Resolve_Integer_Literal (N, Ctx_Type);
2869 when N_Membership_Test =>
2870 Resolve_Membership_Op (N, Ctx_Type);
2872 when N_Null =>
2873 Resolve_Null (N, Ctx_Type);
2875 when N_Op_And
2876 | N_Op_Or
2877 | N_Op_Xor
2878 =>
2879 Resolve_Logical_Op (N, Ctx_Type);
2881 when N_Op_Eq
2882 | N_Op_Ne
2883 =>
2884 Resolve_Equality_Op (N, Ctx_Type);
2886 when N_Op_Ge
2887 | N_Op_Gt
2888 | N_Op_Le
2889 | N_Op_Lt
2890 =>
2891 Resolve_Comparison_Op (N, Ctx_Type);
2893 when N_Op_Not =>
2894 Resolve_Op_Not (N, Ctx_Type);
2896 when N_Op_Add
2897 | N_Op_Divide
2898 | N_Op_Mod
2899 | N_Op_Multiply
2900 | N_Op_Rem
2901 | N_Op_Subtract
2902 =>
2903 Resolve_Arithmetic_Op (N, Ctx_Type);
2905 when N_Op_Concat =>
2906 Resolve_Op_Concat (N, Ctx_Type);
2908 when N_Op_Expon =>
2909 Resolve_Op_Expon (N, Ctx_Type);
2911 when N_Op_Abs
2912 | N_Op_Minus
2913 | N_Op_Plus
2914 =>
2915 Resolve_Unary_Op (N, Ctx_Type);
2917 when N_Op_Shift =>
2918 Resolve_Shift (N, Ctx_Type);
2920 when N_Procedure_Call_Statement =>
2921 Resolve_Call (N, Ctx_Type);
2923 when N_Operator_Symbol =>
2924 Resolve_Operator_Symbol (N, Ctx_Type);
2926 when N_Qualified_Expression =>
2927 Resolve_Qualified_Expression (N, Ctx_Type);
2929 -- Why is the following null, needs a comment ???
2931 when N_Quantified_Expression =>
2932 null;
2934 when N_Raise_Expression =>
2935 Resolve_Raise_Expression (N, Ctx_Type);
2937 when N_Raise_xxx_Error =>
2938 Set_Etype (N, Ctx_Type);
2940 when N_Range =>
2941 Resolve_Range (N, Ctx_Type);
2943 when N_Real_Literal =>
2944 Resolve_Real_Literal (N, Ctx_Type);
2946 when N_Reference =>
2947 Resolve_Reference (N, Ctx_Type);
2949 when N_Selected_Component =>
2950 Resolve_Selected_Component (N, Ctx_Type);
2952 when N_Slice =>
2953 Resolve_Slice (N, Ctx_Type);
2955 when N_String_Literal =>
2956 Resolve_String_Literal (N, Ctx_Type);
2958 when N_Target_Name =>
2959 Resolve_Target_Name (N, Ctx_Type);
2961 when N_Type_Conversion =>
2962 Resolve_Type_Conversion (N, Ctx_Type);
2964 when N_Unchecked_Expression =>
2965 Resolve_Unchecked_Expression (N, Ctx_Type);
2967 when N_Unchecked_Type_Conversion =>
2968 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2969 end case;
2971 -- Mark relevant use-type and use-package clauses as effective using
2972 -- the original node because constant folding may have occured and
2973 -- removed references that need to be examined.
2975 if Nkind (Original_Node (N)) in N_Op then
2976 Mark_Use_Clauses (Original_Node (N));
2977 end if;
2979 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2980 -- expression of an anonymous access type that occurs in the context
2981 -- of a named general access type, except when the expression is that
2982 -- of a membership test. This ensures proper legality checking in
2983 -- terms of allowed conversions (expressions that would be illegal to
2984 -- convert implicitly are allowed in membership tests).
2986 if Ada_Version >= Ada_2012
2987 and then Ekind (Ctx_Type) = E_General_Access_Type
2988 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2989 and then Nkind (Parent (N)) not in N_Membership_Test
2990 then
2991 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2992 Analyze_And_Resolve (N, Ctx_Type);
2993 end if;
2995 -- If the subexpression was replaced by a non-subexpression, then
2996 -- all we do is to expand it. The only legitimate case we know of
2997 -- is converting procedure call statement to entry call statements,
2998 -- but there may be others, so we are making this test general.
3000 if Nkind (N) not in N_Subexpr then
3001 Debug_A_Exit ("resolving ", N, " (done)");
3002 Expand (N);
3003 return;
3004 end if;
3006 -- The expression is definitely NOT overloaded at this point, so
3007 -- we reset the Is_Overloaded flag to avoid any confusion when
3008 -- reanalyzing the node.
3010 Set_Is_Overloaded (N, False);
3012 -- Freeze expression type, entity if it is a name, and designated
3013 -- type if it is an allocator (RM 13.14(10,11,13)).
3015 -- Now that the resolution of the type of the node is complete, and
3016 -- we did not detect an error, we can expand this node. We skip the
3017 -- expand call if we are in a default expression, see section
3018 -- "Handling of Default Expressions" in Sem spec.
3020 Debug_A_Exit ("resolving ", N, " (done)");
3022 -- We unconditionally freeze the expression, even if we are in
3023 -- default expression mode (the Freeze_Expression routine tests this
3024 -- flag and only freezes static types if it is set).
3026 -- Ada 2012 (AI05-177): The declaration of an expression function
3027 -- does not cause freezing, but we never reach here in that case.
3028 -- Here we are resolving the corresponding expanded body, so we do
3029 -- need to perform normal freezing.
3031 -- As elsewhere we do not emit freeze node within a generic. We make
3032 -- an exception for entities that are expressions, only to detect
3033 -- misuses of deferred constants and preserve the output of various
3034 -- tests.
3036 if not Inside_A_Generic or else Is_Entity_Name (N) then
3037 Freeze_Expression (N);
3038 end if;
3040 -- Now we can do the expansion
3042 Expand (N);
3043 end if;
3044 end Resolve;
3046 -------------
3047 -- Resolve --
3048 -------------
3050 -- Version with check(s) suppressed
3052 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3053 begin
3054 if Suppress = All_Checks then
3055 declare
3056 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3057 begin
3058 Scope_Suppress.Suppress := (others => True);
3059 Resolve (N, Typ);
3060 Scope_Suppress.Suppress := Sva;
3061 end;
3063 else
3064 declare
3065 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3066 begin
3067 Scope_Suppress.Suppress (Suppress) := True;
3068 Resolve (N, Typ);
3069 Scope_Suppress.Suppress (Suppress) := Svg;
3070 end;
3071 end if;
3072 end Resolve;
3074 -------------
3075 -- Resolve --
3076 -------------
3078 -- Version with implicit type
3080 procedure Resolve (N : Node_Id) is
3081 begin
3082 Resolve (N, Etype (N));
3083 end Resolve;
3085 ---------------------
3086 -- Resolve_Actuals --
3087 ---------------------
3089 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3090 Loc : constant Source_Ptr := Sloc (N);
3091 A : Node_Id;
3092 A_Id : Entity_Id;
3093 A_Typ : Entity_Id := Empty; -- init to avoid warning
3094 F : Entity_Id;
3095 F_Typ : Entity_Id;
3096 Prev : Node_Id := Empty;
3097 Orig_A : Node_Id;
3098 Real_F : Entity_Id := Empty; -- init to avoid warning
3100 Real_Subp : Entity_Id;
3101 -- If the subprogram being called is an inherited operation for
3102 -- a formal derived type in an instance, Real_Subp is the subprogram
3103 -- that will be called. It may have different formal names than the
3104 -- operation of the formal in the generic, so after actual is resolved
3105 -- the name of the actual in a named association must carry the name
3106 -- of the actual of the subprogram being called.
3108 procedure Check_Aliased_Parameter;
3109 -- Check rules on aliased parameters and related accessibility rules
3110 -- in (RM 3.10.2 (10.2-10.4)).
3112 procedure Check_Argument_Order;
3113 -- Performs a check for the case where the actuals are all simple
3114 -- identifiers that correspond to the formal names, but in the wrong
3115 -- order, which is considered suspicious and cause for a warning.
3117 procedure Check_Prefixed_Call;
3118 -- If the original node is an overloaded call in prefix notation,
3120 -- Try_Object_Operation has already verified that there is a valid
3121 -- interpretation, but the form of the actual can only be determined
3122 -- once the primitive operation is identified.
3125 -- Emit an error concerning the illegal usage of an effectively volatile
3126 -- object in interfering context (SPARK RM 7.13(12)).
3129 -- If the actual is missing in a call, insert in the actuals list
3130 -- an instance of the default expression. The insertion is always
3131 -- a named association.
3134 -- Check whether T1 and T2, or their full views, are derived from a
3135 -- common type. Used to enforce the restrictions on array conversions
3136 -- of AI95-00246.
3139 -- Predicate to determine whether an actual that is a concatenation
3140 -- will be evaluated statically and does not need a transient scope.
3141 -- This must be determined before the actual is resolved and expanded
3142 -- because if needed the transient scope must be introduced earlier.
3144 -----------------------------
3145 -- Check_Aliased_Parameter --
3146 -----------------------------
3151 begin
3159 else
3166 -- In a generic body assume the worst for generic formals:
3167 -- they can have a constrained partial view (AI05-041).
3173 then
3176 else
3181 else
3193 then
3201 then
3202 Error_Msg_N
3208 --------------------------
3209 -- Check_Argument_Order --
3210 --------------------------
3213 begin
3214 -- Nothing to do if no parameters, or original node is neither a
3215 -- function call nor a procedure call statement (happens in the
3216 -- operator-transformed-to-function call case), or the call does
3217 -- not come from source, or this warning is off.
3219 if not Warn_On_Parameter_Order
3223 then
3227 declare
3230 begin
3231 -- Nothing to do if only one parameter
3237 -- Here if at least two arguments
3239 declare
3245 -- Set True if an out of order case is found
3247 begin
3248 -- Collect identifier names of actuals, fail if any actual is
3249 -- not a simple identifier, and record max length of name.
3255 else
3261 -- If we got this far, all actuals are identifiers and the list
3262 -- of their names is stored in the Actuals array.
3267 -- If we ran out of formals, that's odd, probably an error
3268 -- which will be detected elsewhere, but abandon the search.
3274 -- If name matches and is in order OK
3279 else
3280 -- If no match, see if it is elsewhere in list and if so
3281 -- flag potential wrong order if type is compatible.
3285 and then
3287 then
3293 -- No match
3301 -- If Formals left over, also probably an error, skip warning
3307 -- Here we give the warning if something was out of order
3310 Error_Msg_N
3317 -------------------------
3318 -- Check_Prefixed_Call --
3319 -------------------------
3328 begin
3329 -- Check whether the call is a prefixed call, with or without
3330 -- additional actuals.
3333 or else
3339 then
3342 then
3343 -- Introduce dereference on object in prefix
3345 New_A :=
3353 then
3354 -- Introduce an implicit 'Access in prefix
3357 Error_Msg_NE
3373 ---------------------------------------
3374 -- Flag_Effectively_Volatile_Objects --
3375 ---------------------------------------
3379 -- Determine whether arbitrary node N denotes an effectively volatile
3380 -- object and if it does, emit an error.
3382 -----------------
3383 -- Flag_Object --
3384 -----------------
3389 begin
3390 -- Do not consider nested function calls because they have already
3391 -- been processed during their own resolution.
3403 then
3404 Error_Msg_N
3416 -- Start of processing for Flag_Effectively_Volatile_Objects
3418 begin
3422 --------------------
3423 -- Insert_Default --
3424 --------------------
3430 begin
3431 -- Missing argument in call, nothing to insert
3436 else
3437 -- Note that we do a full New_Copy_Tree, so that any associated
3438 -- Itypes are properly copied. This may not be needed any more,
3439 -- but it does no harm as a safety measure. Defaults of a generic
3440 -- formal may be out of bounds of the corresponding actual (see
3441 -- cc1311b) and an additional check may be required.
3443 Actval :=
3444 New_Copy_Tree
3449 -- Propagate dimension information, if any.
3455 then
3461 then
3464 then
3465 -- If default is a real literal, do not introduce a
3466 -- conversion whose effect may depend on the run-time
3467 -- size of universal real.
3471 else
3482 -- Resolve aggregates with their base type, to avoid scope
3483 -- anomalies: the subtype was first built in the subprogram
3484 -- declaration, and the current call may be nested.
3488 else
3492 else
3495 -- See note above concerning aggregates
3499 then
3502 -- Resolve entities with their own type, which may differ from
3503 -- the type of a reference in a generic context (the view
3504 -- swapping mechanism did not anticipate the re-analysis of
3505 -- default values in calls).
3510 else
3515 -- If default is a tag indeterminate function call, propagate tag
3516 -- to obtain proper dispatching.
3520 then
3525 -- If the default expression raises constraint error, then just
3526 -- silently replace it with an N_Raise_Constraint_Error node, since
3527 -- we already gave the warning on the subprogram spec. If node is
3528 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3529 -- the warnings removal machinery.
3533 then
3542 Assoc :=
3547 -- Case of insertion is first named actual
3551 then
3558 else
3562 else
3566 -- Case of insertion is not first named actual
3568 else
3569 Set_Next_Named_Actual
3581 -------------------
3582 -- Same_Ancestor --
3583 -------------------
3589 begin
3592 then
3598 then
3605 --------------------------
3606 -- Static_Concatenation --
3607 --------------------------
3610 begin
3617 -- Concatenation is static when both operands are static and
3618 -- the concatenation operator is a predefined one.
3621 and then
3623 and then
3628 declare
3630 begin
3633 and then
3637 else
3643 -- Start of processing for Resolve_Actuals
3645 begin
3646 Check_Argument_Order;
3650 and then In_Instance
3653 then
3655 else
3660 Check_Prefixed_Call;
3674 -- If we have an error in any actual or formal, indicated by a type
3675 -- of Any_Type, then abandon resolution attempt, and set result type
3676 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3677 -- type is imposed from context.
3681 then
3688 -- Case where actual is present
3690 -- If the actual is an entity, generate a reference to it now. We
3691 -- do this before the actual is resolved, because a formal of some
3692 -- protected subprogram, or a task discriminant, will be rewritten
3693 -- during expansion, and the source entity reference may be lost.
3698 then
3699 -- Annotate the tree by creating a variable reference marker when
3700 -- the actual denotes a variable reference, in case the reference
3701 -- is folded or optimized away. The variable reference marker is
3702 -- automatically saved for later examination by the ABE Processing
3703 -- phase. The status of the reference is set as follows:
3705 -- status mode
3706 -- read IN, IN OUT
3707 -- write IN OUT, OUT
3709 if Needs_Variable_Reference_Marker
3712 then
3713 Build_Variable_Reference_Marker
3724 then
3731 -- RM 6.4.1(12): For an out parameter that is passed by
3732 -- copy, the formal parameter object is created, and:
3734 -- * For an access type, the formal parameter is initialized
3735 -- from the value of the actual, without checking that the
3736 -- value satisfies any constraint, any predicate, or any
3737 -- exclusion of the null value.
3739 -- * For a scalar type that has the Default_Value aspect
3740 -- specified, the formal parameter is initialized from the
3741 -- value of the actual, without checking that the value
3742 -- satisfies any constraint or any predicate.
3743 -- I do not understand why this case is included??? this is
3744 -- not a case where an OUT parameter is treated as IN OUT.
3746 -- * For a composite type with discriminants or that has
3747 -- implicit initial values for any subcomponents, the
3748 -- behavior is as for an in out parameter passed by copy.
3750 -- Hence for these cases we generate the read reference now
3751 -- (the write reference will be generated later by
3752 -- Note_Possible_Modification).
3755 and then
3757 or else
3759 and then
3761 or else
3764 or else Is_Partially_Initialized_Type
3766 then
3776 then
3777 -- If style checking mode on, check match of formal name
3785 -- If the formal is Out or In_Out, do not resolve and expand the
3786 -- conversion, because it is subsequently expanded into explicit
3787 -- temporaries and assignments. However, the object of the
3788 -- conversion can be resolved. An exception is the case of tagged
3789 -- type conversion with a class-wide actual. In that case we want
3790 -- the tag check to occur and no temporary will be needed (no
3791 -- representation change can occur) and the parameter is passed by
3792 -- reference, so we go ahead and resolve the type conversion.
3793 -- Another exception is the case of reference to component or
3794 -- subcomponent of a bit-packed array, in which case we want to
3795 -- defer expansion to the point the in and out assignments are
3796 -- performed.
3801 then
3804 then
3805 -- In a view conversion, the conversion must be legal in
3806 -- both directions, and thus both component types must be
3807 -- aliased, or neither (4.6 (8)).
3809 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3810 -- the privacy requirement should not apply to generic
3811 -- types, and should be checked in an instance. ARG query
3812 -- is in order ???
3816 then
3817 Error_Msg_N
3821 -- Comment here??? what set of cases???
3823 elsif
3825 then
3826 -- Check view conv between unrelated by ref array types
3830 then
3831 Error_Msg_N
3835 -- In Ada 2005 mode, check view conversion component
3836 -- type cannot be private, tagged, or volatile. Note
3837 -- that we only apply this to source conversions. The
3838 -- generated code can contain conversions which are
3839 -- not subject to this test, and we cannot extract the
3840 -- component type in such cases since it is not present.
3844 then
3845 declare
3847 Component_Type
3849 begin
3854 then
3855 Error_Msg_N
3866 -- Resolve expression if conversion is all OK
3871 then
3875 -- If the actual is a function call that returns a limited
3876 -- unconstrained object that needs finalization, create a
3877 -- transient scope for it, so that it can receive the proper
3878 -- finalization list.
3880 elsif Expander_Active
3886 then
3890 -- A small optimization: if one of the actuals is a concatenation
3891 -- create a block around a procedure call to recover stack space.
3892 -- This alleviates stack usage when several procedure calls in
3893 -- the same statement list use concatenation. We do not perform
3894 -- this wrapping for code statements, where the argument is a
3895 -- static string, and we want to preserve warnings involving
3896 -- sequences of such statements.
3898 elsif Expander_Active
3904 then
3908 else
3912 and then
3915 then
3916 Error_Msg_N
3929 -- (Ada 2005: AI-251): If the actual is an allocator whose
3930 -- directly designated type is a class-wide interface, we build
3931 -- an anonymous access type to use it as the type of the
3932 -- allocator. Later, when the subprogram call is expanded, if
3933 -- the interface has a secondary dispatch table the expander
3934 -- will add a type conversion to force the correct displacement
3935 -- of the pointer.
3938 declare
3944 begin
3947 then
3950 Set_Directly_Designated_Type
3955 -- Ada 2005, AI-162:If the actual is an allocator, the
3956 -- innermost enclosing statement is the master of the
3957 -- created object. This needs to be done with expansion
3958 -- enabled only, otherwise the transient scope will not
3959 -- be removed in the expansion of the wrapped construct.
3961 if Expander_Active
3964 then
3965 Establish_Transient_Scope
3975 -- (Ada 2005): The call may be to a primitive operation of a
3976 -- tagged synchronized type, declared outside of the type. In
3977 -- this case the controlling actual must be converted to its
3978 -- corresponding record type, which is the formal type. The
3979 -- actual may be a subtype, either because of a constraint or
3980 -- because it is a generic actual, so use base type to locate
3981 -- concurrent type.
3988 then
3989 -- If the actual is overloaded, look for an interpretation
3990 -- that has a synchronized type.
3995 else
3996 declare
4000 begin
4005 then
4015 declare
4018 begin
4021 else
4025 -- Tagged synchronized type (case 1): the actual is a
4026 -- concurrent type.
4030 then
4032 Unchecked_Convert_To
4036 -- Tagged synchronized type (case 2): the formal is a
4037 -- concurrent type.
4040 and then Present
4045 then
4048 -- Common case
4050 else
4055 -- Not a synchronized operation
4057 else
4065 -- An actual cannot be an untagged formal incomplete type
4070 then
4071 Error_Msg_N
4077 N_Procedure_Call_Statement)
4078 then
4079 -- In formal mode, check that actual parameters matching
4080 -- formals of tagged types are objects (or ancestor type
4081 -- conversions of objects), not general expressions.
4088 declare
4093 begin
4095 Check_SPARK_05_Restriction
4098 -- In formal mode, the only view conversions are those
4099 -- involving ancestor conversion of an extended type.
4101 elsif not
4107 then
4108 if Ekind_In
4110 then
4111 Check_SPARK_05_Restriction
4114 else
4115 Check_SPARK_05_Restriction
4119 else
4124 else
4128 -- In formal mode, the only view conversions are those
4129 -- involving ancestor conversion of an extended type.
4133 then
4134 Check_SPARK_05_Restriction
4140 -- has warnings suppressed, then we reset Never_Set_In_Source for
4141 -- the calling entity. The reason for this is to catch cases like
4142 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4143 -- uses trickery to modify an IN parameter.
4150 then
4154 -- Perform error checks for IN and IN OUT parameters
4158 -- Check unset reference. For scalar parameters, it is clearly
4159 -- wrong to pass an uninitialized value as either an IN or
4160 -- IN-OUT parameter. For composites, it is also clearly an
4161 -- error to pass a completely uninitialized value as an IN
4162 -- parameter, but the case of IN OUT is trickier. We prefer
4163 -- not to give a warning here. For example, suppose there is
4164 -- a routine that sets some component of a record to False.
4165 -- It is perfectly reasonable to make this IN-OUT and allow
4166 -- either initialized or uninitialized records to be passed
4167 -- in this case.
4169 -- For partially initialized composite values, we also avoid
4170 -- warnings, since it is quite likely that we are passing a
4171 -- partially initialized value and only the initialized fields
4172 -- will in fact be read in the subprogram.
4177 then
4181 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4182 -- actual to a nested call, since this constitutes a reading of
4183 -- the parameter, which is not allowed.
4188 then
4193 -- In -gnatd.q mode, forget that a given array is constant when
4194 -- it is passed as an IN parameter to a foreign-convention
4195 -- subprogram. This is in case the subprogram evilly modifies the
4196 -- object. Of course, correct code would use IN OUT.
4198 if Debug_Flag_Dot_Q
4204 then
4208 -- Case of OUT or IN OUT parameter
4212 -- For an Out parameter, check for useless assignment. Note
4213 -- that we can't set Last_Assignment this early, because we may
4214 -- kill current values in Resolve_Call, and that call would
4215 -- clobber the Last_Assignment field.
4217 -- Note: call Warn_On_Useless_Assignment before doing the check
4218 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4219 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4220 -- reflects the last assignment, not this one.
4227 then
4232 -- Validate the form of the actual. Note that the call to
4233 -- Is_OK_Variable_For_Out_Formal generates the required
4234 -- reference in this case.
4236 -- A call to an initialization procedure for an aggregate
4237 -- component may initialize a nested component of a constant
4238 -- designated object. In this context the object is variable.
4242 then
4248 then
4249 Error_Msg_N
4254 Error_Msg_N
4261 -- What's the following about???
4265 else
4266 Kill_All_Checks;
4275 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4279 -- Apply predicate tests except in certain special cases. Note
4280 -- that it might be more consistent to apply these only when
4281 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4282 -- for the outbound predicate tests ??? In any case indicate
4283 -- the function being called, for better warnings if the call
4284 -- leads to an infinite recursion.
4290 -- Apply required constraint checks
4292 -- Gigi looks at the check flag and uses the appropriate types.
4293 -- For now since one flag is used there is an optimization
4294 -- which might not be done in the IN OUT case since Gigi does
4295 -- not do any analysis. More thought required about this ???
4297 -- In fact is this comment obsolete??? doesn't the expander now
4298 -- generate all these tests anyway???
4311 then
4314 -- For view conversions of a discriminated object, apply
4315 -- check to object itself, the conversion alreay has the
4316 -- proper type.
4320 then
4327 then
4333 then
4336 else
4340 -- Ada 2005 (AI-231): Note that the controlling parameter case
4341 -- already existed in Ada 95, which is partially checked
4342 -- elsewhere (see Checks), and we don't want the warning
4343 -- message to differ.
4348 then
4350 Apply_Compile_Time_Constraint_Error
4356 Apply_Compile_Time_Constraint_Error
4365 -- Checks for OUT parameters and IN OUT parameters
4369 -- If there is a type conversion, make sure the return value
4370 -- meets the constraints of the variable before the conversion.
4374 Apply_Scalar_Range_Check
4377 -- In addition, the returned value of the parameter must
4378 -- satisfy the bounds of the object type (see comment
4379 -- below).
4383 else
4384 Apply_Range_Check
4388 -- If no conversion, apply scalar range checks and length check
4389 -- based on the subtype of the actual (NOT that of the formal).
4390 -- This indicates that the check takes place on return from the
4391 -- call. During expansion the required constraint checks are
4392 -- inserted. In GNATprove mode, in the absence of expansion,
4393 -- the flag indicates that the returned value is valid.
4395 else
4401 then
4403 else
4408 -- Note: we do not apply the predicate checks for the case of
4409 -- OUT and IN OUT parameters. They are instead applied in the
4410 -- Expand_Actuals routine in Exp_Ch6.
4413 -- An actual associated with an access parameter is implicitly
4414 -- converted to the anonymous access type of the formal and must
4415 -- satisfy the legality checks for access conversions.
4419 Error_Msg_N
4423 -- If the actual is an access selected component of a variable,
4424 -- the call may modify its designated object. It is reasonable
4425 -- to treat this as a potential modification of the enclosing
4426 -- record, to prevent spurious warnings that it should be
4427 -- declared as a constant, because intuitively programmers
4428 -- regard the designated subcomponent as part of the record.
4433 then
4438 -- Check bad case of atomic/volatile argument (RM C.6(12))
4442 then
4445 then
4446 Error_Msg_NE
4452 then
4453 Error_Msg_NE
4459 -- Check that subprograms don't have improper controlling
4460 -- arguments (RM 3.9.2 (9)).
4462 -- A primitive operation may have an access parameter of an
4463 -- incomplete tagged type, but a dispatching call is illegal
4464 -- if the type is still incomplete.
4470 declare
4472 begin
4476 then
4477 Error_Msg_NE
4488 -- Apply legality rule 3.9.2 (9/1)
4493 and then not In_Instance
4494 then
4499 Error_Msg_NE
4503 -- Apply the checks described in 3.10.2(27): if the context is a
4504 -- specific access-to-object, the actual cannot be class-wide.
4505 -- Use base type to exclude access_to_subprogram cases.
4512 and then
4517 -- Disable these checks for call to imported C++ subprograms
4519 and then not
4523 then
4524 Error_Msg_N
4529 Error_Msg_NE
4534 Check_Aliased_Parameter;
4538 -- If it is a named association, treat the selector_name as a
4539 -- proper identifier, and mark the corresponding entity.
4543 -- Ignore reference in SPARK mode, as it refers to an entity not
4544 -- in scope at the point of reference, so the reference should
4545 -- be ignored for computing effects of subprograms.
4547 and then not GNATprove_Mode
4548 then
4549 -- If subprogram is overridden, use name of formal that
4550 -- is being called.
4556 else
4570 -- The following checks are only relevant when SPARK_Mode is on as
4571 -- they are not standard Ada legality rule. Internally generated
4572 -- temporaries are ignored.
4576 -- An effectively volatile object may act as an actual when the
4577 -- corresponding formal is of a non-scalar effectively volatile
4578 -- type (SPARK RM 7.1.3(11)).
4582 then
4585 -- An effectively volatile object may act as an actual in a
4586 -- call to an instance of Unchecked_Conversion.
4587 -- (SPARK RM 7.1.3(11)).
4592 -- The actual denotes an object
4595 Error_Msg_N
4599 -- Otherwise the actual denotes an expression. Inspect the
4600 -- expression and flag each effectively volatile object with
4601 -- enabled property Async_Writers or Effective_Reads as illegal
4602 -- because it apprears within an interfering context. Note that
4603 -- this is usually done in Resolve_Entity_Name, but when the
4604 -- effectively volatile object appears as an actual in a call,
4605 -- the call must be resolved first.
4607 else
4611 -- An effectively volatile variable cannot act as an actual
4612 -- parameter in a procedure call when the variable has enabled
4613 -- property Effective_Reads and the corresponding formal is of
4614 -- mode IN (SPARK RM 7.1.3(10)).
4619 then
4625 then
4626 Error_Msg_NE
4637 -- A formal parameter of a specific tagged type whose related
4638 -- subprogram is subject to pragma Extensions_Visible with value
4639 -- "False" cannot act as an actual in a subprogram with value
4640 -- "True" (SPARK RM 6.1.7(3)).
4644 Extensions_Visible_True
4645 then
4646 Error_Msg_N
4649 Error_Msg_NE
4653 -- The actual parameter of a Ghost subprogram whose formal is of
4654 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4662 then
4663 Error_Msg_NE
4669 else
4676 -- Case where actual is not present
4678 else
4679 Insert_Default;
4690 -----------------------
4691 -- Resolve_Allocator --
4692 -----------------------
4704 procedure Check_Allocator_Discrim_Accessibility
4707 -- Check that accessibility level associated with an access discriminant
4708 -- initialized in an allocator by the expression Disc_Exp is not deeper
4709 -- than the level of the allocator type Alloc_Typ. An error message is
4710 -- issued if this condition is violated. Specialized checks are done for
4711 -- the cases of a constraint expression which is an access attribute or
4712 -- an access discriminant.
4715 -- If the allocator is an actual in a call, it is allowed to be class-
4716 -- wide when the context is not because it is a controlling actual.
4718 -------------------------------------------
4719 -- Check_Allocator_Discrim_Accessibility --
4720 -------------------------------------------
4722 procedure Check_Allocator_Discrim_Accessibility
4725 is
4726 begin
4729 then
4730 Error_Msg_N
4733 -- When the expression is an Access attribute the level of the prefix
4734 -- object must not be deeper than that of the allocator's type.
4738 Attribute_Access
4741 then
4742 Error_Msg_N
4744 Disc_Exp);
4746 -- When the expression is an access discriminant the check is against
4747 -- the level of the prefix object.
4753 then
4754 Error_Msg_N
4756 Disc_Exp);
4758 -- All other cases are legal
4760 else
4765 ----------------------------
4766 -- In_Dispatching_Context --
4767 ----------------------------
4772 begin
4778 -- Start of processing for Resolve_Allocator
4780 begin
4781 -- Replace general access with specific type
4791 -- For qualified expression, resolve the expression using the given
4792 -- subtype (nothing to do for type mark, subtype indication)
4797 and then not In_Dispatching_Context
4798 then
4799 Error_Msg_N
4807 -- Allocators generated by the build-in-place expansion mechanism
4808 -- are explicitly marked as coming from source but do not need to be
4809 -- checked for limited initialization. To exclude this case, ensure
4810 -- that the parent of the allocator is a source node.
4811 -- The return statement constructed for an Expression_Function does
4812 -- not come from source but requires a limited check.
4816 and then
4818 or else
4822 and then not In_Instance_Body
4823 then
4826 Error_Msg_N
4829 else
4830 Error_Msg_N
4838 -- A qualified expression requires an exact match of the type. Class-
4839 -- wide matching is not allowed.
4844 then
4848 -- Calls to build-in-place functions are not currently supported in
4849 -- allocators for access types associated with a simple storage pool.
4850 -- Supporting such allocators may require passing additional implicit
4851 -- parameters to build-in-place functions (or a significant revision
4852 -- of the current b-i-p implementation to unify the handling for
4853 -- multiple kinds of storage pools). ???
4857 then
4858 declare
4861 begin
4863 and then
4864 Present (Get_Rep_Pragma
4866 then
4867 Error_Msg_N
4874 -- A special accessibility check is needed for allocators that
4875 -- constrain access discriminants. The level of the type of the
4876 -- expression used to constrain an access discriminant cannot be
4877 -- deeper than the type of the allocator (in contrast to access
4878 -- parameters, where the level of the actual can be arbitrary).
4880 -- We can't use Valid_Conversion to perform this check because in
4881 -- general the type of the allocator is unrelated to the type of
4882 -- the access discriminant.
4886 then
4893 then
4896 -- Get the first component expression of the aggregate
4906 else
4910 else
4929 else
4934 else
4943 -- For a subtype mark or subtype indication, freeze the subtype
4945 else
4949 Error_Msg_N
4953 -- A special accessibility check is needed for allocators that
4954 -- constrain access discriminants. The level of the type of the
4955 -- expression used to constrain an access discriminant cannot be
4956 -- deeper than the type of the allocator (in contrast to access
4957 -- parameters, where the level of the actual can be arbitrary).
4958 -- We can't use Valid_Conversion to perform this check because
4959 -- in general the type of the allocator is unrelated to the type
4960 -- of the access discriminant.
4965 then
4975 else
4989 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4990 -- check that the level of the type of the created object is not deeper
4991 -- than the level of the allocator's access type, since extensions can
4992 -- now occur at deeper levels than their ancestor types. This is a
4993 -- static accessibility level check; a run-time check is also needed in
4994 -- the case of an initialized allocator with a class-wide argument (see
4995 -- Expand_Allocator_Expression).
4999 then
5000 declare
5003 begin
5008 else
5014 then
5017 Error_Msg_N
5026 -- Do not apply Ada 2005 accessibility checks on a class-wide
5027 -- allocator if the type given in the allocator is a formal
5028 -- type. A run-time check will be performed in the instance.
5038 -- Check for allocation from an empty storage pool
5043 -- If the context is an unchecked conversion, as may happen within an
5044 -- inlined subprogram, the allocator is being resolved with its own
5045 -- anonymous type. In that case, if the target type has a specific
5046 -- storage pool, it must be inherited explicitly by the allocator type.
5050 then
5051 Set_Associated_Storage_Pool
5059 -- Check that an allocator with task parts isn't for a nested access
5060 -- type when restriction No_Task_Hierarchy applies.
5064 then
5068 -- An illegal allocator may be rewritten as a raise Program_Error
5069 -- statement.
5073 -- Avoid coextension processing for an allocator that is the
5074 -- expansion of a build-in-place function call.
5078 N_Qualified_Expression
5080 N_Function_Call
5081 and then Is_Expanded_Build_In_Place_Call
5083 then
5086 else
5087 -- An anonymous access discriminant is the definition of a
5088 -- coextension.
5092 N_Discriminant_Specification
5093 then
5094 declare
5098 begin
5101 -- Ada 2012 AI05-0052: If the designated type of the
5102 -- allocator is limited, then the allocator shall not
5103 -- be used to define the value of an access discriminant
5104 -- unless the discriminated type is immutably limited.
5109 then
5110 Error_Msg_N
5113 N);
5117 -- Avoid marking an allocator as a dynamic coextension if it is
5118 -- within a static construct.
5123 -- Finalization and deallocation of coextensions utilizes an
5124 -- approximate implementation which does not directly adhere
5125 -- to the semantic rules. Warn on potential issues involving
5126 -- coextensions.
5129 Error_Msg_N
5132 else
5133 Error_Msg_N
5139 -- Cleanup for potential static coextensions
5141 else
5145 -- Anonymous access-to-controlled objects are not finalized on
5146 -- time because this involves run-time ownership and currently
5147 -- this property is not available. In rare cases the object may
5148 -- not be finalized at all. Warn on potential issues involving
5149 -- anonymous access-to-controlled objects.
5153 then
5154 Error_Msg_N
5164 -- Report a simple error: if the designated object is a local task,
5165 -- its body has not been seen yet, and its activation will fail an
5166 -- elaboration check.
5173 then
5179 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5180 -- type with a task component on a subpool. This action must raise
5181 -- Program_Error at runtime.
5187 then
5199 ---------------------------
5200 -- Resolve_Arithmetic_Op --
5201 ---------------------------
5203 -- Used for resolving all arithmetic operators except exponentiation
5214 -- We do the resolution using the base type, because intermediate values
5215 -- in expressions always are of the base type, not a subtype of it.
5218 -- Returns True if N is in a context that expects "any real type"
5221 -- Return True iff given type is Integer or universal real/integer
5224 -- Choose type of integer literal in fixed-point operation to conform
5225 -- to available fixed-point type. T is the type of the other operand,
5226 -- which is needed to determine the expected type of N.
5229 -- Set operand type to T if universal
5231 -------------------------------
5232 -- Expected_Type_Is_Any_Real --
5233 -------------------------------
5236 begin
5237 -- N is the expression after "delta" in a fixed_point_definition;
5238 -- see RM-3.5.9(6):
5241 N_Decimal_Fixed_Point_Definition,
5243 -- N is one of the bounds in a real_range_specification;
5244 -- see RM-3.5.7(5):
5246 N_Real_Range_Specification,
5248 -- N is the expression of a delta_constraint;
5249 -- see RM-J.3(3):
5251 N_Delta_Constraint);
5254 -----------------------------
5255 -- Is_Integer_Or_Universal --
5256 -----------------------------
5263 begin
5269 else
5275 then
5286 ----------------------------
5287 -- Set_Mixed_Mode_Operand --
5288 ----------------------------
5294 begin
5297 -- A universal integer literal is resolved as standard integer
5298 -- except in the case of a fixed-point result, where we leave it
5299 -- as universal (to be handled by Exp_Fixd later on)
5303 else
5311 then
5312 -- A universal real can appear in a fixed-type context. We resolve
5313 -- the literal with that context, even though this might raise an
5314 -- exception prematurely (the other operand may be zero).
5321 then
5322 -- Integer arg in mixed-mode operation. Resolve with universal
5323 -- type, in case preference rule must be applied.
5329 -- If the operand is part of a fixed multiplication operation,
5330 -- a conversion will be applied to each operand, so resolve it
5331 -- with its own type.
5336 else
5337 -- Not a mixed-mode operation, resolve with context
5344 -- N may itself be a mixed-mode operation, so use context type
5351 then
5352 -- Must be (fixed * fixed) operation, operand must have one
5353 -- compatible interpretation.
5360 then
5361 -- C * F(X) in a fixed context, where C is a real literal or a
5362 -- fixed-point expression. F must have either a fixed type
5363 -- interpretation or an integer interpretation, but not both.
5370 else
5377 else
5385 -- Reanalyze the literal with the fixed type of the context. If
5386 -- context is Universal_Fixed, we are within a conversion, leave
5387 -- the literal as a universal real because there is no usable
5388 -- fixed type, and the target of the conversion plays no role in
5389 -- the resolution.
5391 declare
5395 begin
5398 else
5404 then
5406 else
5414 -- A universal real conditional expression can appear in a fixed-type
5415 -- context and must be resolved with that context to facilitate the
5416 -- code generation in the back end.
5421 then
5424 else
5429 ----------------------
5430 -- Set_Operand_Type --
5431 ----------------------
5434 begin
5437 then
5442 -- Start of processing for Resolve_Arithmetic_Op
5444 begin
5449 then
5453 -- Special-case for mixed-mode universal expressions or fixed point type
5454 -- operation: each argument is resolved separately. The same treatment
5455 -- is required if one of the operands of a fixed point operation is
5456 -- universal real, since in this case we don't do a conversion to a
5457 -- specific fixed-point type (instead the expander handles the case).
5459 -- Set the type of the node to its universal interpretation because
5460 -- legality checks on an exponentiation operand need the context.
5465 then
5476 or else
5479 then
5484 -- If context is a fixed type and one operand is integer, the other
5485 -- is resolved with the type of the context.
5490 then
5497 then
5501 -- If both operands are universal and the context is a floating
5502 -- point type, the operands are resolved to the type of the context.
5508 else
5513 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5514 -- multiplying operators from being used when the expected type is
5515 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5516 -- some cases where the expected type is actually Any_Real;
5517 -- Expected_Type_Is_Any_Real takes care of that case.
5521 then
5525 N_Unchecked_Type_Conversion)
5526 then
5533 else
5536 and then not
5538 N_Unchecked_Type_Conversion)
5539 then
5540 Error_Msg_N
5545 -- The expected type is "any real type" in contexts like
5547 -- type T is delta <universal_fixed-expression> ...
5549 -- in which case we need to set the type to Universal_Real
5550 -- so that static expression evaluation will work properly.
5554 else
5564 then
5569 -- If no previous errors, this is only possible if one operand is
5570 -- overloaded and the context is universal. Resolve as such.
5575 else
5577 and then
5579 then
5583 -- If the context is Universal_Fixed and the operands are also
5584 -- universal fixed, this is an error, unless there is only one
5585 -- applicable fixed_point type (usually Duration).
5593 else
5598 else
5603 -- If one of the arguments was resolved to a non-universal type.
5604 -- label the result of the operation itself with the same type.
5605 -- Do the same for the universal argument, if any.
5617 -- In SPARK, a multiplication or division with operands of fixed point
5618 -- types must be qualified or explicitly converted to identify the
5619 -- result type.
5624 and then
5626 then
5627 Check_SPARK_05_Restriction
5631 -- Set overflow and division checking bit
5638 -- Give warning if explicit division by zero
5642 then
5648 or else
5651 then
5652 -- Specialize the warning message according to the operation.
5653 -- When SPARK_Mode is On, force a warning instead of an error
5654 -- in that case, as this likely corresponds to deactivated
5655 -- code. The following warnings are for the case
5660 -- For division, we have two cases, for float division
5661 -- of an unconstrained float type, on a machine where
5662 -- Machine_Overflows is false, we don't get an exception
5663 -- at run-time, but rather an infinity or Nan. The Nan
5664 -- case is pretty obscure, so just warn about infinities.
5668 and then not Machine_Overflows_On_Target
5669 then
5670 Error_Msg_N
5674 -- For all other cases, we get a Constraint_Error
5676 else
5677 Apply_Compile_Time_Constraint_Error
5684 Apply_Compile_Time_Constraint_Error
5690 Apply_Compile_Time_Constraint_Error
5695 -- Division by zero can only happen with division, rem,
5696 -- and mod operations.
5702 -- In GNATprove mode, we enable the division check so that
5703 -- GNATprove will issue a message if it cannot be proved.
5709 -- Otherwise just set the flag to check at run time
5711 else
5716 -- If Restriction No_Implicit_Conditionals is active, then it is
5717 -- violated if either operand can be negative for mod, or for rem
5718 -- if both operands can be negative.
5722 then
5723 declare
5730 -- Set if corresponding operand might be negative
5732 begin
5733 Determine_Range
5737 Determine_Range
5741 -- Check if we will be generating conditionals. There are two
5742 -- cases where that can happen, first for REM, the only case
5743 -- is largest negative integer mod -1, where the division can
5744 -- overflow, but we still have to give the right result. The
5745 -- front end generates a test for this annoying case. Here we
5746 -- just test if both operands can be negative (that's what the
5747 -- expander does, so we match its logic here).
5749 -- The second case is mod where either operand can be negative.
5750 -- In this case, the back end has to generate additional tests.
5753 or else
5755 then
5766 ------------------
5767 -- Resolve_Call --
5768 ------------------
5771 function Same_Or_Aliased_Subprograms
5774 -- Returns True if the subprogram entity S is the same as E or else
5775 -- S is an alias of E.
5777 ---------------------------------
5778 -- Same_Or_Aliased_Subprograms --
5779 ---------------------------------
5781 function Same_Or_Aliased_Subprograms
5784 is
5786 begin
5790 -- Local variables
5804 -- Start of processing for Resolve_Call
5806 begin
5807 -- Preserve relevant elaboration-related attributes of the context which
5808 -- are no longer available or very expensive to recompute once analysis,
5809 -- resolution, and expansion are over.
5811 Mark_Elaboration_Attributes
5817 -- The context imposes a unique interpretation with type Typ on a
5818 -- procedure or function call. Find the entity of the subprogram that
5819 -- yields the expected type, and propagate the corresponding formal
5820 -- constraints on the actuals. The caller has established that an
5821 -- interpretation exists, and emitted an error if not unique.
5823 -- First deal with the case of a call to an access-to-subprogram,
5824 -- dereference made explicit in Analyze_Call.
5830 else
5831 -- Find the interpretation whose type (a subprogram type) has a
5832 -- return type that is compatible with the context. Analysis of
5833 -- the node has established that one exists.
5852 -- If the prefix is not an entity, then resolve it
5858 -- For an indirect call, we always invalidate checks, since we do not
5859 -- know whether the subprogram is local or global. Yes we could do
5860 -- better here, e.g. by knowing that there are no local subprograms,
5861 -- but it does not seem worth the effort. Similarly, we kill all
5862 -- knowledge of current constant values.
5864 Kill_Current_Values;
5866 -- If this is a procedure call which is really an entry call, do
5867 -- the conversion of the procedure call to an entry call. Protected
5868 -- operations use the same circuitry because the name in the call
5869 -- can be an arbitrary expression with special resolution rules.
5874 then
5881 -- Annotate the tree by creating a call marker in case the original
5882 -- call is transformed by expansion. The call marker is automatically
5883 -- saved for later examination by the ABE Processing phase.
5887 -- Kill checks and constant values, as above for indirect case
5888 -- Who knows what happens when another task is activated?
5890 Kill_Current_Values;
5893 -- Normal subprogram call with name established in Resolve
5899 -- Otherwise we must have the case of an overloaded call
5901 else
5904 -- Initialize Nam to prevent warning (we know it will be assigned
5905 -- in the loop below, but the compiler does not know that).
5925 then
5926 -- The prefix is a parameterless function call that returns an access
5927 -- to subprogram. If parameters are present in the current call, add
5928 -- add an explicit dereference. We use the base type here because
5929 -- within an instance these may be subtypes.
5931 -- The dereference is added either in Analyze_Call or here. Should
5932 -- be consolidated ???
5941 -- Check that a call to Current_Task does not occur in an entry body
5944 declare
5947 begin
5949 loop
5952 -- Exclude calls that occur within the default of a formal
5953 -- parameter of the entry, since those are evaluated outside
5954 -- of the body.
5961 then
5964 Error_Msg_NE
5978 -- Check that a procedure call does not occur in the context of the
5979 -- entry call statement of a conditional or timed entry call. Note that
5980 -- the case of a call to a subprogram renaming of an entry will also be
5981 -- rejected. The test for N not being an N_Entry_Call_Statement is
5982 -- defensive, covering the possibility that the processing of entry
5983 -- calls might reach this point due to later modifications of the code
5984 -- above.
5989 then
5993 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5994 -- for a procedure_or_entry_call, the procedure_name or
5995 -- procedure_prefix of the procedure_call_statement shall denote
5996 -- an entry renamed by a procedure, or (a view of) a primitive
5997 -- subprogram of a limited interface whose first parameter is
5998 -- a controlling parameter.
6003 then
6004 Error_Msg_N
6009 -- If the SPARK_05 restriction is active, we are not allowed
6010 -- to have a call to a subprogram before we see its completion.
6015 -- Don't flag strange internal calls
6020 -- Only flag calls in extended main source
6025 -- Exclude enumeration literals from this processing
6028 then
6029 Check_SPARK_05_Restriction
6033 -- Check that this is not a call to a protected procedure or entry from
6034 -- within a protected function.
6038 -- Freeze the subprogram name if not in a spec-expression. Note that
6039 -- we freeze procedure calls as well as function calls. Procedure calls
6040 -- are not frozen according to the rules (RM 13.14(14)) because it is
6041 -- impossible to have a procedure call to a non-frozen procedure in
6042 -- pure Ada, but in the code that we generate in the expander, this
6043 -- rule needs extending because we can generate procedure calls that
6044 -- need freezing.
6046 -- In Ada 2012, expression functions may be called within pre/post
6047 -- conditions of subsequent functions or expression functions. Such
6048 -- calls do not freeze when they appear within generated bodies,
6049 -- (including the body of another expression function) which would
6050 -- place the freeze node in the wrong scope. An expression function
6051 -- is frozen in the usual fashion, by the appearance of a real body,
6052 -- or at the end of a declarative part.
6055 and then not In_Spec_Expression
6057 and then
6060 then
6064 -- For a predefined operator, the type of the result is the type imposed
6065 -- by context, except for a predefined operation on universal fixed.
6066 -- Otherwise The type of the call is the type returned by the subprogram
6067 -- being called.
6074 -- If the subprogram returns an array type, and the context requires the
6075 -- component type of that array type, the node is really an indexing of
6076 -- the parameterless call. Resolve as such. A pathological case occurs
6077 -- when the type of the component is an access to the array type. In
6078 -- this case the call is truly ambiguous. If the call is to an intrinsic
6079 -- subprogram, it can't be an indexed component. This check is necessary
6080 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6081 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6082 -- pointers to the same array), the compiler gets confused and does an
6083 -- infinite recursion.
6086 and then
6089 or else
6092 and then
6095 then
6096 declare
6101 begin
6104 then
6105 Error_Msg_N
6107 else
6110 -- The called entity may be an explicit dereference, in which
6111 -- case there is no entity to set.
6119 or else
6121 and then
6123 then
6126 -- Indexed call to a parameterless function
6128 Index_Node :=
6130 Prefix =>
6133 else
6134 -- An Ada 2005 prefixed call to a primitive operation
6135 -- whose first parameter is the prefix. This prefix was
6136 -- prepended to the parameter list, which is actually a
6137 -- list of indexes. Remove the prefix in order to build
6138 -- the proper indexed component.
6140 Index_Node :=
6142 Prefix =>
6145 Parameter_Associations =>
6146 New_List
6151 -- Preserve the parenthesis count of the node
6155 -- Since we are correcting a node classification error made
6156 -- by the parser, we call Replace rather than Rewrite.
6168 -- Annotate the tree by creating a call marker in case
6169 -- the original call is transformed by expansion. The call
6170 -- marker is automatically saved for later examination by
6171 -- the ABE Processing phase.
6180 else
6181 -- If the called function is not declared in the main unit and it
6182 -- returns the limited view of type then use the available view (as
6183 -- is done in Try_Object_Operation) to prevent back-end confusion;
6184 -- for the function entity itself. The call must appear in a context
6185 -- where the nonlimited view is available. If the function entity is
6186 -- in the extended main unit then no action is needed, because the
6187 -- back end handles this case. In either case the type of the call
6188 -- is the nonlimited view.
6192 then
6199 else
6204 -- In the case where the call is to an overloaded subprogram, Analyze
6205 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6206 -- such a case Normalize_Actuals needs to be called once more to order
6207 -- the actuals correctly. Otherwise the call will have the ordering
6208 -- given by the last overloaded subprogram whether this is the correct
6209 -- one being called or not.
6216 -- In any case, call is fully resolved now. Reset Overload flag, to
6217 -- prevent subsequent overload resolution if node is analyzed again
6222 -- A Ghost entity must appear in a specific context
6228 -- If we are calling the current subprogram from immediately within its
6229 -- body, then that is the case where we can sometimes detect cases of
6230 -- infinite recursion statically. Do not try this in case restriction
6231 -- No_Recursion is in effect anyway, and do it only for source calls.
6236 -- Check violation of SPARK_05 restriction which does not permit
6237 -- a subprogram body to contain a call to the subprogram directly.
6241 then
6242 Check_SPARK_05_Restriction
6246 -- Issue warning for possible infinite recursion in the absence
6247 -- of the No_Recursion restriction.
6252 then
6253 -- Here we detected and flagged an infinite recursion, so we do
6254 -- not need to test the case below for further warnings. Also we
6255 -- are all done if we now have a raise SE node.
6261 -- If call is to immediately containing subprogram, then check for
6262 -- the case of a possible run-time detectable infinite recursion.
6264 else
6268 -- Although in general case, recursion is not statically
6269 -- checkable, the case of calling an immediately containing
6270 -- subprogram is easy to catch.
6274 -- If the recursive call is to a parameterless subprogram,
6275 -- then even if we can't statically detect infinite
6276 -- recursion, this is pretty suspicious, and we output a
6277 -- warning. Furthermore, we will try later to detect some
6278 -- cases here at run time by expanding checking code (see
6279 -- Detect_Infinite_Recursion in package Exp_Ch6).
6281 -- If the recursive call is within a handler, do not emit a
6282 -- warning, because this is a common idiom: loop until input
6283 -- is correct, catch illegal input in handler and restart.
6289 then
6290 -- For the case of a procedure call. We give the message
6291 -- only if the call is the first statement in a sequence
6292 -- of statements, or if all previous statements are
6293 -- simple assignments. This is simply a heuristic to
6294 -- decrease false positives, without losing too many good
6295 -- warnings. The idea is that these previous statements
6296 -- may affect global variables the procedure depends on.
6297 -- We also exclude raise statements, that may arise from
6298 -- constraint checks and are probably unrelated to the
6299 -- intended control flow.
6303 then
6304 declare
6306 begin
6310 N_Raise_Constraint_Error)
6311 then
6320 -- Do not give warning if we are in a conditional context
6322 declare
6324 begin
6330 then
6335 -- Here warning is to be issued
6351 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6355 -- If subprogram name is a predefined operator, it was given in
6356 -- functional notation. Replace call node with operator node, so
6357 -- that actuals can be resolved appropriately.
6365 then
6371 -- Create a transient scope if the resulting type requires it
6373 -- There are several notable exceptions:
6375 -- a) In init procs, the transient scope overhead is not needed, and is
6376 -- even incorrect when the call is a nested initialization call for a
6377 -- component whose expansion may generate adjust calls. However, if the
6378 -- call is some other procedure call within an initialization procedure
6379 -- (for example a call to Create_Task in the init_proc of the task
6380 -- run-time record) a transient scope must be created around this call.
6382 -- b) Enumeration literal pseudo-calls need no transient scope
6384 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6385 -- functions) do not use the secondary stack even though the return
6386 -- type may be unconstrained.
6388 -- d) Calls to a build-in-place function, since such functions may
6389 -- allocate their result directly in a target object, and cases where
6390 -- the result does get allocated in the secondary stack are checked for
6391 -- within the specialized Exp_Ch6 procedures for expanding those
6392 -- build-in-place calls.
6394 -- e) Calls to inlinable expression functions do not use the secondary
6395 -- stack (since the call will be replaced by its returned object).
6397 -- f) If the subprogram is marked Inline_Always, then even if it returns
6398 -- an unconstrained type the call does not require use of the secondary
6399 -- stack. However, inlining will only take place if the body to inline
6400 -- is already present. It may not be available if e.g. the subprogram is
6401 -- declared in a child instance.
6407 then
6414 then
6417 elsif Expander_Active
6420 then
6423 -- If the call appears within the bounds of a loop, it will be
6424 -- rewritten and reanalyzed, nothing left to do here.
6431 -- A protected function cannot be called within the definition of the
6432 -- enclosing protected type, unless it is part of a pre/postcondition
6433 -- on another protected operation. This may appear in the entry wrapper
6434 -- created for an entry with preconditions.
6439 and then not In_Spec_Expression
6441 then
6442 Error_Msg_NE
6446 -- Propagate interpretation to actuals, and add default expressions
6447 -- where needed.
6452 -- Overloaded literals are rewritten as function calls, for purpose of
6453 -- resolution. After resolution, we can replace the call with the
6454 -- literal itself.
6460 -- Avoid validation, since it is a static function call
6466 -- If the subprogram is not global, then kill all saved values and
6467 -- checks. This is a bit conservative, since in many cases we could do
6468 -- better, but it is not worth the effort. Similarly, we kill constant
6469 -- values. However we do not need to do this for internal entities
6470 -- (unless they are inherited user-defined subprograms), since they
6471 -- are not in the business of molesting local values.
6473 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6474 -- kill all checks and values for calls to global subprograms. This
6475 -- takes care of the case where an access to a local subprogram is
6476 -- taken, and could be passed directly or indirectly and then called
6477 -- from almost any context.
6479 -- Note: we do not do this step till after resolving the actuals. That
6480 -- way we still take advantage of the current value information while
6481 -- scanning the actuals.
6483 -- We suppress killing values if we are processing the nodes associated
6484 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6485 -- type kills all the values as part of analyzing the code that
6486 -- initializes the dispatch tables.
6490 or else Suppress_Value_Tracking_On_Call
6495 then
6496 Kill_Current_Values;
6499 -- If we are warning about unread OUT parameters, this is the place to
6500 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6501 -- after the above call to Kill_Current_Values (since that call clears
6502 -- the Last_Assignment field of all local variables).
6507 then
6508 declare
6512 begin
6522 then
6532 -- If the subprogram is a primitive operation, check whether or not
6533 -- it is a correct dispatching call.
6537 then
6542 and then not In_Instance
6543 then
6547 -- If this is a dispatching call, generate the appropriate reference,
6548 -- for better source navigation in GPS.
6552 then
6555 -- Normal case, not a dispatching call: generate a call reference
6557 else
6565 -- Check for violation of restriction No_Specific_Termination_Handlers
6566 -- and warn on a potentially blocking call to Abort_Task.
6570 or else
6572 then
6579 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6580 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6581 -- need to check the second argument to determine whether it is an
6582 -- absolute or relative timing event.
6587 then
6591 -- Issue an error for a call to an eliminated subprogram. This routine
6592 -- will not perform the check if the call appears within a default
6593 -- expression.
6597 -- In formal mode, the primitive operations of a tagged type or type
6598 -- extension do not include functions that return the tagged type.
6604 then
6608 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6609 -- class-wide and the call dispatches on result in a context that does
6610 -- not provide a tag, the call raises Program_Error.
6613 and then In_Instance
6618 then
6619 -- Verify that none of the formals are controlling
6621 declare
6625 begin
6647 -- Check for calling a function with OUT or IN OUT parameter when the
6648 -- calling context (us right now) is not Ada 2012, so does not allow
6649 -- OUT or IN OUT parameters in function calls. Functions declared in
6650 -- a predefined unit are OK, as they may be called indirectly from a
6651 -- user-declared instantiation.
6657 then
6662 -- Check the dimensions of the actuals in the call. For function calls,
6663 -- propagate the dimensions from the returned type to N.
6667 -- All done, evaluate call and deal with elaboration issues
6675 -- Annotate the tree by creating a call marker in case the original call
6676 -- is transformed by expansion. The call marker is automatically saved
6677 -- for later examination by the ABE Processing phase.
6681 -- In GNATprove mode, expansion is disabled, but we want to inline some
6682 -- subprograms to facilitate formal verification. Indirect calls through
6683 -- a subprogram type or within a generic cannot be inlined. Inlining is
6684 -- performed only for calls subject to SPARK_Mode on.
6686 if GNATprove_Mode
6689 and then not Inside_A_Generic
6690 then
6697 -- Nothing to do if the subprogram is not eligible for inlining in
6698 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6702 or else Debug_Flag_M
6703 then
6706 -- Calls cannot be inlined inside assertions, as GNATprove treats
6707 -- assertions as logic expressions. Only issue a message when the
6708 -- body has been seen, otherwise this leads to spurious messages
6709 -- on expression functions.
6713 Cannot_Inline
6717 -- Calls cannot be inlined inside default expressions
6720 Cannot_Inline
6723 -- Inlining should not be performed during preanalysis
6727 -- Do not inline calls inside expression functions or functions
6728 -- generated by the front end for subtype predicates, as this
6729 -- would prevent interpreting them as logical formulas in
6730 -- GNATprove. Only issue a message when the body has been seen,
6731 -- otherwise this leads to spurious messages on callees that
6732 -- are themselves expression functions.
6735 and then
6740 then
6743 then
6745 Cannot_Inline
6750 Cannot_Inline
6755 Cannot_Inline
6759 else
6760 Cannot_Inline
6766 -- With the one-pass inlining technique, a call cannot be
6767 -- inlined if the corresponding body has not been seen yet.
6770 Cannot_Inline
6773 -- Nothing to do if there is no body to inline, indicating that
6774 -- the subprogram is not suitable for inlining in GNATprove
6775 -- mode.
6780 -- Calls cannot be inlined inside potentially unevaluated
6781 -- expressions, as this would create complex actions inside
6782 -- expressions, that are not handled by GNATprove.
6785 Cannot_Inline
6789 -- Do not inline calls which would possibly lead to missing a
6790 -- type conversion check on an input parameter.
6793 Cannot_Inline
6797 -- Otherwise, inline the call
6799 else
6811 -----------------------------
6812 -- Resolve_Case_Expression --
6813 -----------------------------
6821 begin
6833 -- When the expression is of a scalar subtype different from the
6834 -- result subtype, then insert a conversion to ensure the generation
6835 -- of a constraint check.
6845 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6846 -- dynamically tagged must be known statically.
6854 Error_Msg_N
6868 -------------------------------
6869 -- Resolve_Character_Literal --
6870 -------------------------------
6876 begin
6877 -- Verify that the character does belong to the type of the context
6882 -- Wide_Wide_Character literals must always be defined, since the set
6883 -- of wide wide character literals is complete, i.e. if a character
6884 -- literal is accepted by the parser, then it is OK for wide wide
6885 -- character (out of range character literals are rejected).
6890 -- Always accept character literal for type Any_Character, which
6891 -- occurs in error situations and in comparisons of literals, both
6892 -- of which should accept all literals.
6897 -- For Standard.Character or a type derived from it, check that the
6898 -- literal is in range.
6905 -- For Standard.Wide_Character or a type derived from it, check that the
6906 -- literal is in range.
6913 -- If the entity is already set, this has already been resolved in a
6914 -- generic context, or comes from expansion. Nothing else to do.
6919 -- Otherwise we have a user defined character type, and we can use the
6920 -- standard visibility mechanisms to locate the referenced entity.
6922 else
6935 -- If we fall through, then the literal does not match any of the
6936 -- entries of the enumeration type. This isn't just a constraint error
6937 -- situation, it is an illegality (see RM 4.2).
6939 Error_Msg_NE
6943 ---------------------------
6944 -- Resolve_Comparison_Op --
6945 ---------------------------
6947 -- Context requires a boolean type, and plays no role in resolution.
6948 -- Processing identical to that for equality operators. The result type is
6949 -- the base type, which matters when pathological subtypes of booleans with
6950 -- limited ranges are used.
6957 begin
6958 -- If this is an intrinsic operation which is not predefined, use the
6959 -- types of its declared arguments to resolve the possibly overloaded
6960 -- operands. Otherwise the operands are unambiguous and specify the
6961 -- expected type.
6966 else
6977 -- Skip remaining processing if already set to Any_Type
6983 -- Deal with other error cases
6987 T = Any_Character
6988 then
6991 else
6999 -- Resolve the operands if types OK
7008 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
7009 -- types or array types except String.
7012 Check_SPARK_05_Restriction
7017 then
7018 Check_SPARK_05_Restriction
7022 -- Check comparison on unordered enumeration
7026 Error_Msg_NE
7033 -- Evaluate the relation (note we do this after the above check since
7034 -- this Eval call may change N to True/False. Skip this evaluation
7035 -- inside assertions, in order to keep assertions as written by users
7036 -- for tools that rely on these, e.g. GNATprove for loop invariants.
7037 -- Except evaluation is still performed even inside assertions for
7038 -- comparisons between values of universal type, which are useless
7039 -- for static analysis tools, and not supported even by GNATprove.
7043 and then
7045 then
7050 -----------------------------------------
7051 -- Resolve_Discrete_Subtype_Indication --
7052 -----------------------------------------
7054 procedure Resolve_Discrete_Subtype_Indication
7057 is
7061 begin
7069 else
7079 Error_Msg_NE
7082 -- Rewrite the constraint as a range of Typ
7083 -- to allow compilation to proceed further.
7095 else
7099 -- Additionally, we must check that the bounds are compatible
7100 -- with the given subtype, which might be different from the
7101 -- type of the context.
7105 -- ??? If the above check statically detects a Constraint_Error
7106 -- it replaces the offending bound(s) of the range R with a
7107 -- Constraint_Error node. When the itype which uses these bounds
7108 -- is frozen the resulting call to Duplicate_Subexpr generates
7109 -- a new temporary for the bounds.
7111 -- Unfortunately there are other itypes that are also made depend
7112 -- on these bounds, so when Duplicate_Subexpr is called they get
7113 -- a forward reference to the newly created temporaries and Gigi
7114 -- aborts on such forward references. This is probably sign of a
7115 -- more fundamental problem somewhere else in either the order of
7116 -- itype freezing or the way certain itypes are constructed.
7118 -- To get around this problem we call Remove_Side_Effects right
7119 -- away if either bounds of R are a Constraint_Error.
7121 declare
7125 begin
7141 -------------------------
7142 -- Resolve_Entity_Name --
7143 -------------------------
7145 -- Used to resolve identifiers and expanded names
7148 function Is_Assignment_Or_Object_Expression
7151 -- Determine whether node Context denotes an assignment statement or an
7152 -- object declaration whose expression is node Expr.
7154 ----------------------------------------
7155 -- Is_Assignment_Or_Object_Expression --
7156 ----------------------------------------
7158 function Is_Assignment_Or_Object_Expression
7161 is
7162 begin
7164 N_Object_Declaration)
7166 then
7169 -- Check whether a construct that yields a name is the expression of
7170 -- an assignment statement or an object declaration.
7173 N_Explicit_Dereference,
7174 N_Indexed_Component,
7175 N_Selected_Component,
7176 N_Slice)
7178 or else
7180 N_Unchecked_Type_Conversion)
7182 then
7183 return
7184 Is_Assignment_Or_Object_Expression
7188 -- Otherwise the context is not an assignment statement or an object
7189 -- declaration.
7191 else
7196 -- Local variables
7201 -- Start of processing for Resolve_Entity_Name
7203 begin
7204 -- If garbage from errors, set to Any_Type and return
7211 -- Replace named numbers by corresponding literals. Note that this is
7212 -- the one case where Resolve_Entity_Name must reset the Etype, since
7213 -- it is currently marked as universal.
7223 -- For enumeration literals, we need to make sure that a proper style
7224 -- check is done, since such literals are overloaded, and thus we did
7225 -- not do a style check during the first phase of analysis.
7231 -- Case of (sub)type name appearing in a context where an expression
7232 -- is expected. This is legal if occurrence is a current instance.
7233 -- See RM 8.6 (17/3).
7239 -- Any other use is an error
7241 else
7242 Error_Msg_N
7246 -- Check discriminant use if entity is discriminant in current scope,
7247 -- i.e. discriminant of record or concurrent type currently being
7248 -- analyzed. Uses in corresponding body are unrestricted.
7253 then
7256 -- A parameterless generic function cannot appear in a context that
7257 -- requires resolution.
7262 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7263 -- array types (i.e. bounds and length) are legal.
7271 or else Is_Assignment_Or_Object_Expression
7274 then
7279 -- In all other cases, just do the possible static evaluation
7281 else
7282 -- A deferred constant that appears in an expression must have a
7283 -- completion, unless it has been removed by in-place expansion of
7284 -- an aggregate. A constant that is a renaming does not need
7285 -- initialization.
7291 and then not In_Spec_Expression
7294 then
7298 then
7300 else
7301 Error_Msg_N
7311 -- When the entity appears in a parameter association, retrieve the
7312 -- related subprogram call.
7320 -- The following checks are only relevant when SPARK_Mode is on as
7321 -- they are not standard Ada legality rules.
7325 -- An effectively volatile object subject to enabled properties
7326 -- Async_Writers or Effective_Reads must appear in non-interfering
7327 -- context (SPARK RM 7.1.3(12)).
7334 then
7335 SPARK_Msg_N
7340 -- Check for possible elaboration issues with respect to reads of
7341 -- variables. The act of renaming the variable is not considered a
7342 -- read as it simply establishes an alias.
7344 if Legacy_Elaboration_Checks
7346 and then Dynamic_Elaboration_Checks
7348 then
7353 -- The variable may eventually become a constituent of a single
7354 -- protected/task type. Record the reference now and verify its
7355 -- legality when analyzing the contract of the variable
7356 -- (SPARK RM 9.3).
7362 -- A Ghost entity must appear in a specific context
7369 -- We may be resolving an entity within expanded code, so a reference to
7370 -- an entity should be ignored when calculating effective use clauses to
7371 -- avoid inappropriate marking.
7378 -------------------
7379 -- Resolve_Entry --
7380 -------------------
7392 -- If the bounds of the entry family being called depend on task
7393 -- discriminants, build a new index subtype where a discriminant is
7394 -- replaced with the value of the discriminant of the target task.
7395 -- The target task is the prefix of the entry name in the call.
7397 -----------------------
7398 -- Actual_Index_Type --
7399 -----------------------
7409 -- If the bound is given by a discriminant, replace with a reference
7410 -- to the discriminant of the same name in the target task. If the
7411 -- entry name is the target of a requeue statement and the entry is
7412 -- in the current protected object, the bound to be used is the
7413 -- discriminal of the object (see Apply_Range_Checks for details of
7414 -- the transformation).
7416 -----------------------------
7417 -- Actual_Discriminant_Ref --
7418 -----------------------------
7424 begin
7429 then
7435 then
7436 -- Note: here Bound denotes a discriminant of the corresponding
7437 -- record type tskV, whose discriminal is a formal of the
7438 -- init-proc tskVIP. What we want is the body discriminal,
7439 -- which is associated to the discriminant of the original
7440 -- concurrent type tsk.
7442 return New_Occurrence_Of
7445 else
7446 Ref :=
7456 -- Start of processing for Actual_Index_Type
7458 begin
7461 then
7464 else
7478 -- Start of processing for Resolve_Entry
7480 begin
7481 -- Find name of entry being called, and resolve prefix of name with its
7482 -- own type. The prefix can be overloaded, and the name and signature of
7483 -- the entry must be taken into account.
7487 -- Case of dealing with entry family within the current tasks
7491 else
7497 -- Entry call to an entry (or entry family) in the current task. This
7498 -- is legal even though the task will deadlock. Rewrite as call to
7499 -- current task.
7501 -- This can also be a call to an entry in an enclosing task. If this
7502 -- is a single task, we have to retrieve its name, because the scope
7503 -- of the entry is the task type, not the object. If the enclosing
7504 -- task is a task type, the identity of the task is given by its own
7505 -- self variable.
7507 -- Finally this can be a requeue on an entry of the same task or
7508 -- protected object.
7515 then
7516 -- S is an enclosing task or protected object. The concurrent
7517 -- declaration has been converted into a type declaration, and
7518 -- the object itself has an object declaration that follows
7519 -- the type in the same declarative part.
7531 -- Call to current task. Will be transformed into call to Self
7538 New_N :=
7541 Selector_Name =>
7548 then
7549 -- Use the entry name (which must be unique at this point) to find
7550 -- the prefix that returns the corresponding task/protected type.
7552 declare
7558 begin
7580 -- Generate a reference for the index when it denotes an entity
7586 -- Up to this point the expression could have been the actual in a
7587 -- simple entry call, and be given by a named association.
7591 else
7597 ------------------------
7598 -- Resolve_Entry_Call --
7599 ------------------------
7610 begin
7611 -- We kill all checks here, because it does not seem worth the effort to
7612 -- do anything better, an entry call is a big operation.
7614 Kill_All_Checks;
7616 -- Processing of the name is similar for entry calls and protected
7617 -- operation calls. Once the entity is determined, we can complete
7618 -- the resolution of the actuals.
7620 -- The selector may be overloaded, in the case of a protected object
7621 -- with overloaded functions. The type of the context is used for
7622 -- resolution.
7627 then
7628 declare
7632 begin
7651 -- Simple entry or protected operation call
7664 -- Call to member of entry family
7671 -- We cannot in general check the maximum depth of protected entry calls
7672 -- at compile time. But we can tell that any protected entry call at all
7673 -- violates a specified nesting depth of zero.
7679 -- Use context type to disambiguate a protected function that can be
7680 -- called without actuals and that returns an array type, and where the
7681 -- argument list may be an indexing of the returned value.
7686 and then
7692 and then
7693 Covers
7696 then
7697 declare
7700 begin
7701 Index_Node :=
7703 Prefix =>
7707 -- Since we are correcting a node classification error made by the
7708 -- parser, we call Replace rather than Rewrite.
7721 then
7722 -- Note the entity being called before rewriting the call, so that
7723 -- it appears used at this point.
7727 -- Rewrite as call to the precondition wrapper, adding the task
7728 -- object to the list of actuals. If the call is to a member of an
7729 -- entry family, include the index as well.
7731 declare
7735 begin
7744 New_Call :=
7746 Name =>
7751 -- Preanalyze and resolve new call. Current procedure is called
7752 -- from Resolve_Call, after which expansion will take place.
7759 -- The operation name may have been overloaded. Order the actuals
7760 -- according to the formals of the resolved entity, and set the return
7761 -- type to that of the operation.
7768 -- Reset the Is_Overloaded flag, since resolution is now completed
7770 -- Simple entry call
7775 -- Call to a member of an entry family
7785 -- Create a call reference to the entry
7793 -- Verify that a procedure call cannot masquerade as an entry
7794 -- call where an entry call is expected.
7799 then
7804 then
7809 then
7814 -- After resolution, entry calls and protected procedure calls are
7815 -- changed into entry calls, for expansion. The structure of the node
7816 -- does not change, so it can safely be done in place. Protected
7817 -- function calls must keep their structure because they are
7818 -- subexpressions.
7822 -- A protected operation that is not a function may modify the
7823 -- corresponding object, and cannot apply to a constant. If this
7824 -- is an internal call, the prefix is the type itself.
7830 then
7831 Error_Msg_N
7833 Entry_Name);
7836 declare
7839 begin
7840 Entry_Call :=
7845 -- Inherit relevant attributes from the original call
7847 Set_First_Named_Actual
7850 Set_Is_Elaboration_Checks_OK_Node
7853 Set_Is_Elaboration_Warnings_OK_Node
7856 Set_Is_SPARK_Mode_On_Node
7863 -- Protected functions can return on the secondary stack, in which case
7864 -- we must trigger the transient scope mechanism.
7866 elsif Expander_Active
7868 then
7873 -------------------------
7874 -- Resolve_Equality_Op --
7875 -------------------------
7877 -- Both arguments must have the same type, and the boolean context does
7878 -- not participate in the resolution. The first pass verifies that the
7879 -- interpretation is not ambiguous, and the type of the left argument is
7880 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7881 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7882 -- though they carry a single (universal) type. Diagnose this case here.
7890 -- The resolution rule for if expressions requires that each such must
7891 -- have a unique type. This means that if several dependent expressions
7892 -- are of a non-null anonymous access type, and the context does not
7893 -- impose an expected type (as can be the case in an equality operation)
7894 -- the expression must be rejected.
7897 -- Attempt to explain the nature of a redundant comparison with True. If
7898 -- the expression N is too complex, this routine issues a general error
7899 -- message.
7902 -- In the case of allocators and access attributes, the context must
7903 -- provide an indication of the specific access type to be used. If
7904 -- one operand is of such a "generic" access type, check whether there
7905 -- is a specific visible access type that has the same designated type.
7906 -- This is semantically dubious, and of no interest to any real code,
7907 -- but c48008a makes it all worthwhile.
7909 -------------------------
7910 -- Check_If_Expression --
7911 -------------------------
7917 begin
7924 then
7930 ------------------------
7931 -- Explain_Redundancy --
7932 ------------------------
7939 begin
7942 -- Strip the operand down to an entity
7944 loop
7947 else
7952 -- The construct denotes an entity
7957 -- Do not generate an error message when the comparison is done
7958 -- against the enumeration literal Standard.True.
7962 -- Build a customized error message
7989 -- The construct is too complex to disect, issue a general message
7991 else
7996 -----------------------------
7997 -- Find_Unique_Access_Type --
7998 -----------------------------
8005 begin
8007 E_Access_Attribute_Type)
8008 then
8012 E_Access_Attribute_Type)
8013 then
8015 else
8027 then
8040 -- Start of processing for Resolve_Equality_Op
8042 begin
8053 T = Any_Character
8054 then
8057 else
8066 then
8075 -- If expressions must have a single type, and if the context does
8076 -- not impose one the dependent expressions cannot be anonymous
8077 -- access types.
8079 -- Why no similar processing for case expressions???
8083 E_Anonymous_Access_Subprogram_Type)
8085 E_Anonymous_Access_Subprogram_Type)
8086 then
8094 -- In SPARK, equality operators = and /= for array types other than
8095 -- String are only defined when, for each index position, the
8096 -- operands have equal static bounds.
8100 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8101 -- operation if not needed.
8109 then
8110 Check_SPARK_05_Restriction
8115 -- If the unique type is a class-wide type then it will be expanded
8116 -- into a dispatching call to the predefined primitive. Therefore we
8117 -- check here for potential violation of such restriction.
8123 -- Only warn for redundant equality comparison to True for objects
8124 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8125 -- other expressions, it may be a matter of preference to write
8126 -- "Expr = True" or "Expr".
8128 if Warn_On_Redundant_Constructs
8133 and then
8135 or else
8137 then
8138 Error_Msg_N -- CODEFIX
8148 -- If this is an inequality, it may be the implicit inequality
8149 -- created for a user-defined operation, in which case the corres-
8150 -- ponding equality operation is not intrinsic, and the operation
8151 -- cannot be constant-folded. Else fold.
8156 or else Is_Intrinsic_Subprogram
8158 then
8164 then
8168 -- Ada 2005: If one operand is an anonymous access type, convert the
8169 -- other operand to it, to ensure that the underlying types match in
8170 -- the back-end. Same for access_to_subprogram, and the conversion
8171 -- verifies that the types are subtype conformant.
8173 -- We apply the same conversion in the case one of the operands is a
8174 -- private subtype of the type of the other.
8176 -- Why the Expander_Active test here ???
8178 if Expander_Active
8179 and then
8181 E_Anonymous_Access_Subprogram_Type)
8183 then
8203 ----------------------------------
8204 -- Resolve_Explicit_Dereference --
8205 ----------------------------------
8213 -- The candidate prefix type, if overloaded
8218 begin
8222 -- A useful optimization: check whether the dereference denotes an
8223 -- element of a container, and if so rewrite it as a call to the
8224 -- corresponding Element function.
8226 -- Disabled for now, on advice of ARG. A more restricted form of the
8227 -- predicate might be acceptable ???
8229 -- if Is_Container_Element (N) then
8230 -- return;
8231 -- end if;
8235 -- Use the context type to select the prefix that has the correct
8236 -- designated type. Keep the first match, which will be the inner-
8237 -- most.
8244 then
8249 -- Remove access types that do not match, but preserve access
8250 -- to subprogram interpretations, in case a further dereference
8251 -- is needed (see below).
8264 else
8265 -- If no interpretation covers the designated type of the prefix,
8266 -- this is the pathological case where not all implementations of
8267 -- the prefix allow the interpretation of the node as a call. Now
8268 -- that the expected type is known, Remove other interpretations
8269 -- from prefix, rewrite it as a call, and resolve again, so that
8270 -- the proper call node is generated.
8281 New_N :=
8283 Name =>
8294 -- If not overloaded, resolve P with its own type
8296 else
8300 -- If the prefix might be null, add an access check
8304 then
8308 -- If the designated type is a packed unconstrained array type, and the
8309 -- explicit dereference is not in the context of an attribute reference,
8310 -- then we must compute and set the actual subtype, since it is needed
8311 -- by Gigi. The reason we exclude the attribute case is that this is
8312 -- handled fine by Gigi, and in fact we use such attributes to build the
8313 -- actual subtype. We also exclude generated code (which builds actual
8314 -- subtypes directly if they are needed).
8321 then
8327 -- Note: No Eval processing is required for an explicit dereference,
8328 -- because such a name can never be static.
8332 -------------------------------------
8333 -- Resolve_Expression_With_Actions --
8334 -------------------------------------
8337 begin
8340 -- If N has no actions, and its expression has been constant folded,
8341 -- then rewrite N as just its expression. Note, we can't do this in
8342 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8343 -- Expression (N) to be expanded again.
8347 then
8352 ----------------------------------
8353 -- Resolve_Generalized_Indexing --
8354 ----------------------------------
8362 begin
8363 -- In ASIS mode, propagate the information about the indexes back to
8364 -- to the original indexing node. The generalized indexing is either
8365 -- a function call, or a dereference of one. The actuals include the
8366 -- prefix of the original node, which is the container expression.
8375 loop
8384 -- If expression is to be reanalyzed, reset Generalized_Indexing
8385 -- to recreate call node, as is the case when the expression is
8386 -- part of an expression function.
8395 else
8401 ---------------------------
8402 -- Resolve_If_Expression --
8403 ---------------------------
8412 begin
8413 -- Defend against malformed expressions
8431 -- When the "then" expression is of a scalar subtype different from the
8432 -- result subtype, then insert a conversion to ensure the generation of
8433 -- a constraint check. The same is done for the else part below, again
8434 -- comparing subtypes rather than base types.
8441 -- If ELSE expression present, just resolve using the determined type
8442 -- If type is universal, resolve to any member of the class.
8451 else
8461 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8462 -- dynamically tagged must be known statically.
8467 then
8473 -- If no ELSE expression is present, root type must be Standard.Boolean
8474 -- and we provide a Standard.True result converted to the appropriate
8475 -- Boolean type (in case it is a derived boolean type).
8478 Else_Expr :=
8483 else
8497 -------------------------------
8498 -- Resolve_Indexed_Component --
8499 -------------------------------
8507 begin
8515 -- Use the context type to select the prefix that yields the correct
8516 -- component type.
8518 declare
8525 begin
8532 and then
8533 Covers
8536 then
8545 else
8551 else
8562 else
8569 -- If prefix is access type, dereference to get real array type.
8570 -- Note: we do not apply an access check because the expander always
8571 -- introduces an explicit dereference, and the check will happen there.
8577 -- If name was overloaded, set component type correctly now
8578 -- If a misplaced call to an entry family (which has no index types)
8579 -- return. Error will be diagnosed from calling context.
8583 else
8590 -- The prefix may have resolved to a string literal, in which case its
8591 -- etype has a special representation. This is only possible currently
8592 -- if the prefix is a static concatenation, written in functional
8593 -- notation.
8598 else
8605 else
8616 -- Do not generate the warning on suspicious index if we are analyzing
8617 -- package Ada.Tags; otherwise we will report the warning with the
8618 -- Prims_Ptr field of the dispatch table.
8621 or else not
8623 Ada_Tags)
8624 then
8629 -- If the array type is atomic, and the component is not atomic, then
8630 -- this is worth a warning, since we have a situation where the access
8631 -- to the component may cause extra read/writes of the atomic array
8632 -- object, or partial word accesses, which could be unexpected.
8638 and then Has_Atomic_Components
8641 then
8642 Error_Msg_N
8644 Error_Msg_N
8649 -----------------------------
8650 -- Resolve_Integer_Literal --
8651 -----------------------------
8654 begin
8659 --------------------------------
8660 -- Resolve_Intrinsic_Operator --
8661 --------------------------------
8670 -- If the operand is a literal, it cannot be the expression in a
8671 -- conversion. Use a qualified expression instead.
8673 ---------------------
8674 -- Convert_Operand --
8675 ---------------------
8681 begin
8683 Res :=
8689 else
8696 -- Start of processing for Resolve_Intrinsic_Operator
8698 begin
8699 -- We must preserve the original entity in a generic setting, so that
8700 -- the legality of the operation can be verified in an instance.
8715 -- If the result or operand types are private, rewrite with unchecked
8716 -- conversions on the operands and the result, to expose the proper
8717 -- underlying numeric type.
8722 then
8727 else
8748 then
8749 -- Add explicit conversion where needed, and save interpretations in
8750 -- case operands are overloaded.
8757 else
8763 else
8773 else
8778 --------------------------------------
8779 -- Resolve_Intrinsic_Unary_Operator --
8780 --------------------------------------
8782 procedure Resolve_Intrinsic_Unary_Operator
8785 is
8790 begin
8809 else
8814 ------------------------
8815 -- Resolve_Logical_Op --
8816 ------------------------
8821 begin
8824 -- Predefined operations on scalar types yield the base type. On the
8825 -- other hand, logical operations on arrays yield the type of the
8826 -- arguments (and the context).
8830 else
8834 -- The following test is required because the operands of the operation
8835 -- may be literals, in which case the resulting type appears to be
8836 -- compatible with a signed integer type, when in fact it is compatible
8837 -- only with modular types. If the context itself is universal, the
8838 -- operation is illegal.
8846 Error_Msg_N
8854 then
8858 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8859 -- is active and the result type is standard Boolean (do not mess with
8860 -- ops that return a nonstandard Boolean type, because something strange
8861 -- is going on).
8863 -- Note: you might expect this replacement to be done during expansion,
8864 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8865 -- is used, no part of the right operand of an "and" or "or" operator
8866 -- should be executed if the left operand would short-circuit the
8867 -- evaluation of the corresponding "and then" or "or else". If we left
8868 -- the replacement to expansion time, then run-time checks associated
8869 -- with such operands would be evaluated unconditionally, due to being
8870 -- before the condition prior to the rewriting as short-circuit forms
8871 -- during expansion.
8873 if Short_Circuit_And_Or
8876 then
8877 -- Mark the corresponding putative SCO operator as truly a logical
8878 -- (and short-circuit) operator.
8891 -- Case of OR changed to OR ELSE
8893 else
8901 -- Return now, since analysis of the rewritten ops will take care of
8902 -- other reference bookkeeping and expression folding.
8917 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8918 -- only when both operands have same static lower and higher bounds. Of
8919 -- course the types have to match, so only check if operands are
8920 -- compatible and the node itself has no errors.
8924 then
8925 declare
8929 begin
8930 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8931 -- operation if not needed.
8938 then
8939 Check_SPARK_05_Restriction
8946 ---------------------------
8947 -- Resolve_Membership_Op --
8948 ---------------------------
8950 -- The context can only be a boolean type, and does not determine the
8951 -- arguments. Arguments should be unambiguous, but the preference rule for
8952 -- universal types applies.
8962 -- Analysis has determined a unique type for the left operand. Use it to
8963 -- resolve the disjuncts.
8965 ----------------------------
8966 -- Resolve_Set_Membership --
8967 ----------------------------
8973 begin
8974 -- If the left operand is overloaded, find type compatible with not
8975 -- overloaded alternative of the right operand.
8984 else
8989 -- Unclear how to resolve expression if all alternatives are also
8990 -- overloaded.
8996 else
9005 -- Alternative is an expression, a range
9006 -- or a subtype mark.
9010 then
9017 -- Check for duplicates for discrete case
9020 declare
9029 begin
9030 -- Loop checking duplicates. This is quadratic, but giant sets
9031 -- are unlikely in this context so it's a reasonable choice.
9038 N_Character_Literal)
9040 then
9057 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
9058 -- limited types, evaluation of a membership test uses the predefined
9059 -- equality for the type. This may be confusing to users, and the
9060 -- following warning appears useful for the most common case.
9064 then
9065 Error_Msg_NE
9067 Error_Msg_N
9072 -- Start of processing for Resolve_Membership_Op
9074 begin
9080 Resolve_Set_Membership;
9084 and then
9086 or else
9089 then
9092 -- Ada 2005 (AI-251): Support the following case:
9094 -- type I is interface;
9095 -- type T is tagged ...
9097 -- function Test (O : I'Class) is
9098 -- begin
9099 -- return O in T'Class.
9100 -- end Test;
9102 -- In this case we have nothing else to do. The membership test will be
9103 -- done at run time.
9109 then
9111 else
9115 -- If mixed-mode operations are present and operands are all literal,
9116 -- the only interpretation involves Duration, which is probably not
9117 -- the intention of the programmer.
9132 then
9138 else
9143 -- Here after resolving membership operation
9150 ------------------
9151 -- Resolve_Null --
9152 ------------------
9157 begin
9158 -- Handle restriction against anonymous null access values This
9159 -- restriction can be turned off using -gnatdj.
9161 -- Ada 2005 (AI-231): Remove restriction
9164 and then not Debug_Flag_J
9167 then
9168 -- In the common case of a call which uses an explicitly null value
9169 -- for an access parameter, give specialized error message.
9172 Error_Msg_N
9175 -- Standard message for all other cases (are there any?)
9177 else
9178 Error_Msg_N
9183 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9184 -- assignment to a null-excluding object.
9189 then
9192 -- Decide whether to generate an if_statement around our
9193 -- null-excluding check to avoid them on certain internal object
9194 -- declarations by looking at the type the current Init_Proc
9195 -- belongs to.
9197 -- Generate:
9198 -- if T1b_skip_null_excluding_check then
9199 -- [constraint_error "access check failed"]
9200 -- end if;
9202 if Needs_Conditional_Null_Excluding_Check
9204 then
9207 Condition =>
9209 New_External_Name
9211 Then_Statements =>
9212 New_List (
9216 -- Otherwise, simply create the check
9218 else
9223 else
9224 Insert_Action
9232 -- In a distributed context, null for a remote access to subprogram may
9233 -- need to be replaced with a special record aggregate. In this case,
9234 -- return after having done the transformation.
9239 then
9243 -- The null literal takes its type from the context
9248 -----------------------
9249 -- Resolve_Op_Concat --
9250 -----------------------
9254 -- We wish to avoid deep recursion, because concatenations are often
9255 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9256 -- operands nonrecursively until we find something that is not a simple
9257 -- concatenation (A in this case). We resolve that, and then walk back
9258 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9259 -- to do the rest of the work at each level. The Parent pointers allow
9260 -- us to avoid recursion, and thus avoid running out of memory. See also
9261 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9266 begin
9267 -- The following code is equivalent to:
9269 -- Resolve_Op_Concat_First (NN, Typ);
9270 -- Resolve_Op_Concat_Arg (N, ...);
9271 -- Resolve_Op_Concat_Rest (N, Typ);
9273 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9274 -- operand is a concatenation.
9276 -- Walk down left operands
9278 loop
9287 -- Now (given the above example) NN is A&B and Op1 is A
9289 -- First resolve Op1 ...
9293 -- ... then walk NN back up until we reach N (where we started), calling
9294 -- Resolve_Op_Concat_Rest along the way.
9296 loop
9303 Check_SPARK_05_Restriction
9308 ---------------------------
9309 -- Resolve_Op_Concat_Arg --
9310 ---------------------------
9312 procedure Resolve_Op_Concat_Arg
9317 is
9321 begin
9323 if Is_Comp
9327 then
9329 else
9333 -- If both Array & Array and Array & Component are visible, there is a
9334 -- potential ambiguity that must be reported.
9339 then
9343 -- If the operation is user-defined and not overloaded use its
9344 -- profile. The operation may be a renaming, in which case it has
9345 -- been rewritten, and we want the original profile.
9350 then
9352 Etype
9356 -- Otherwise an aggregate may match both the array type and the
9357 -- component type.
9359 else
9364 else
9368 then
9369 declare
9374 begin
9379 -- Special-case the error message when the overloading is
9380 -- caused by a function that yields an array and can be
9381 -- called without parameters.
9386 Error_Msg_NE
9388 Error_Msg_NE
9392 else
9400 or else
9402 then
9403 Error_Msg_N -- CODEFIX
9421 else
9426 else
9430 -- Concatenation is restricted in SPARK: each operand must be either a
9431 -- string literal, the name of a string constant, a static character or
9432 -- string expression, or another concatenation. Arg cannot be a
9433 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9434 -- separately on each final operand, past concatenation operations.
9438 Check_SPARK_05_Restriction
9446 then
9447 Check_SPARK_05_Restriction
9451 -- Do not issue error on an operand that is neither a character nor a
9452 -- string, as the error is issued in Resolve_Op_Concat.
9454 else
9461 -----------------------------
9462 -- Resolve_Op_Concat_First --
9463 -----------------------------
9470 begin
9471 -- The parser folds an enormous sequence of concatenations of string
9472 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9473 -- in the right operand. If the expression resolves to a predefined "&"
9474 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9475 -- we give an error. See P_Simple_Expression in Par.Ch4.
9480 then
9495 ----------------------------
9496 -- Resolve_Op_Concat_Rest --
9497 ----------------------------
9503 begin
9512 -- If this is not a static concatenation, but the result is a string
9513 -- type (and not an array of strings) ensure that static string operands
9514 -- have their subtypes properly constructed.
9518 then
9524 ----------------------
9525 -- Resolve_Op_Expon --
9526 ----------------------
9531 begin
9532 -- Catch attempts to do fixed-point exponentiation with universal
9533 -- operands, which is a case where the illegality is not caught during
9534 -- normal operator analysis. This is not done in preanalysis mode
9535 -- since the tree is not fully decorated during preanalysis.
9547 then
9557 then
9564 then
9568 -- We do the resolution using the base type, because intermediate values
9569 -- in expressions are always of the base type, not a subtype of it.
9574 -- For integer types, right argument must be in Natural range
9589 -- Evaluate the exponentiation operator for dimensioned type
9592 else
9596 -- Set overflow checking bit. Much cleverer code needed here eventually
9597 -- and perhaps the Resolve routines should be separated for the various
9598 -- arithmetic operations, since they will need different processing. ???
9607 --------------------
9608 -- Resolve_Op_Not --
9609 --------------------
9615 -- This function determines if the parent node is a boolean operator or
9616 -- operation (comparison op, membership test, or short circuit form) and
9617 -- the not in question is the left operand of this operation. Note that
9618 -- if the not is in parens, then false is returned.
9620 -----------------------
9621 -- Parent_Is_Boolean --
9622 -----------------------
9625 begin
9629 else
9631 when N_And_Then
9632 | N_In
9633 | N_Not_In
9634 | N_Op_And
9635 | N_Op_Eq
9636 | N_Op_Ge
9637 | N_Op_Gt
9638 | N_Op_Le
9639 | N_Op_Lt
9640 | N_Op_Ne
9641 | N_Op_Or
9642 | N_Op_Xor
9643 | N_Or_Else
9644 =>
9653 -- Start of processing for Resolve_Op_Not
9655 begin
9656 -- Predefined operations on scalar types yield the base type. On the
9657 -- other hand, logical operations on arrays yield the type of the
9658 -- arguments (and the context).
9662 else
9666 -- Straightforward case of incorrect arguments
9673 -- Special case of probable missing parens
9677 Error_Msg_N
9680 else
9681 Error_Msg_N
9688 -- OK resolution of NOT
9690 else
9691 -- Warn if non-boolean types involved. This is a case like not a < b
9692 -- where a and b are modular, where we will get (not a) < b and most
9693 -- likely not (a < b) was intended.
9695 if Warn_On_Questionable_Missing_Parens
9697 and then Parent_Is_Boolean
9698 then
9702 -- Warn on double negation if checking redundant constructs
9704 if Warn_On_Redundant_Constructs
9709 then
9713 -- Complete resolution and evaluation of NOT
9723 -----------------------------
9724 -- Resolve_Operator_Symbol --
9725 -----------------------------
9727 -- Nothing to be done, all resolved already
9733 begin
9737 ----------------------------------
9738 -- Resolve_Qualified_Expression --
9739 ----------------------------------
9747 begin
9750 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9751 -- operation if not needed.
9758 then
9759 Check_SPARK_05_Restriction
9763 -- A qualified expression requires an exact match of the type, class-
9764 -- wide matching is not allowed. However, if the qualifying type is
9765 -- specific and the expression has a class-wide type, it may still be
9766 -- okay, since it can be the result of the expansion of a call to a
9767 -- dispatching function, so we also have to check class-wideness of the
9768 -- type of the expression's original node.
9771 or else
9775 then
9779 -- If the target type is unconstrained, then we reset the type of the
9780 -- result from the type of the expression. For other cases, the actual
9781 -- subtype of the expression is the target type.
9785 then
9792 -- If we still have a qualified expression after the static evaluation,
9793 -- then apply a scalar range check if needed. The reason that we do this
9794 -- after the Eval call is that otherwise, the application of the range
9795 -- check may convert an illegal static expression and result in warning
9796 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9802 -- Finally, check whether a predicate applies to the target type. This
9803 -- comes from AI12-0100. As for type conversions, check the enclosing
9804 -- context to prevent an infinite expansion.
9810 or else
9812 then
9815 -- In the case of a qualified expression in an allocator, the check
9816 -- is applied when expanding the allocator, so avoid redundant check.
9820 then
9826 ------------------------------
9827 -- Resolve_Raise_Expression --
9828 ------------------------------
9831 begin
9835 else
9840 -------------------
9841 -- Resolve_Range --
9842 -------------------
9849 -- Returns True if N is of the form X'First .. X'Last where X is the
9850 -- same entity for both attributes.
9852 --------------------
9853 -- First_Last_Ref --
9854 --------------------
9860 begin
9865 then
9866 declare
9869 begin
9873 then
9882 -- Start of processing for Resolve_Range
9884 begin
9887 -- The lower bound should be in Typ. The higher bound can be in Typ's
9888 -- base type if the range is null. It may still be invalid if it is
9889 -- higher than the lower bound. This is checked later in the context in
9890 -- which the range appears.
9895 -- Reanalyze the lower bound after both bounds have been analyzed, so
9896 -- that the range is known to be static or not by now. This may trigger
9897 -- more compile-time evaluation, which is useful for static analysis
9898 -- with GNATprove. This is not needed for compilation or static analysis
9899 -- with CodePeer, as full expansion does that evaluation then.
9906 -- Check for inappropriate range on unordered enumeration type
9910 -- Exclude X'First .. X'Last if X is the same entity for both
9912 and then not First_Last_Ref
9913 then
9915 Error_Msg_NE
9922 -- We have to check the bounds for being within the base range as
9923 -- required for a non-static context. Normally this is automatic and
9924 -- done as part of evaluating expressions, but the N_Range node is an
9925 -- exception, since in GNAT we consider this node to be a subexpression,
9926 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9927 -- this, but that would put the test on the main evaluation path for
9928 -- expressions.
9933 -- Check for an ambiguous range over character literals. This will
9934 -- happen with a membership test involving only literals.
9942 -- If bounds are static, constant-fold them, so size computations are
9943 -- identical between front-end and back-end. Do not perform this
9944 -- transformation while analyzing generic units, as type information
9945 -- would be lost when reanalyzing the constant node in the instance.
9958 --------------------------
9959 -- Resolve_Real_Literal --
9960 --------------------------
9965 begin
9966 -- Special processing for fixed-point literals to make sure that the
9967 -- value is an exact multiple of small where this is required. We skip
9968 -- this for the universal real case, and also for generic types.
9974 then
9975 declare
9982 begin
9983 -- Case of literal is not an exact multiple of the Small
9987 -- For a source program literal for a decimal fixed-point type,
9988 -- this is statically illegal (RM 4.9(36)).
9993 then
9997 -- Generate a warning if literal from source
10000 and then Warn_On_Bad_Fixed_Value
10001 then
10002 Error_Msg_N
10004 N);
10007 -- Replace literal by a value that is the exact representation
10008 -- of a value of the type, i.e. a multiple of the small value,
10009 -- by truncation, since Machine_Rounds is false for all GNAT
10010 -- fixed-point types (RM 4.9(38)).
10020 -- In all cases, set the corresponding integer field
10026 -- Now replace the actual type by the expected type as usual
10032 -----------------------
10033 -- Resolve_Reference --
10034 -----------------------
10039 begin
10040 -- Replace general access with specific type
10048 -- If we are taking the reference of a volatile entity, then treat it as
10049 -- a potential modification of this entity. This is too conservative,
10050 -- but necessary because remove side effects can cause transformations
10051 -- of normal assignments into reference sequences that otherwise fail to
10052 -- notice the modification.
10059 --------------------------------
10060 -- Resolve_Selected_Component --
10061 --------------------------------
10076 -- Check whether this is the initialization of a component within an
10077 -- init proc (by assignment or call to another init proc). If true,
10078 -- there is no need for a discriminant check.
10080 --------------------
10081 -- Init_Component --
10082 --------------------
10085 begin
10086 return Inside_Init_Proc
10092 -- Start of processing for Resolve_Selected_Component
10094 begin
10097 -- Use the context type to select the prefix that has a selector
10098 -- of the correct name and type.
10106 else
10110 -- Locate selected component. For a private prefix the selector
10111 -- can denote a discriminant.
10115 -- The visible components of a class-wide type are those of
10116 -- the root type.
10126 then
10133 else
10137 Error_Msg_N
10142 else
10145 -- There may be an implicit dereference. Retrieve
10146 -- designated record type.
10150 else
10156 -- Resolution chooses the new interpretation.
10157 -- Find the component with the right name.
10162 loop
10179 -- There must be a legal interpretation at this point
10186 -- The type of the context and that of the component are
10187 -- compatible and in general identical, but if they are anonymous
10188 -- access-to-subprogram types, the relevant type is that of the
10189 -- component. This matters in Unnest_Subprograms mode, where the
10190 -- relevant context is the one in which the type is declared, not
10191 -- the point of use. This determines what activation record to use.
10197 else
10198 -- Resolve prefix with its type
10203 -- Generate cross-reference. We needed to wait until full overloading
10204 -- resolution was complete to do this, since otherwise we can't tell if
10205 -- we are an lvalue or not.
10209 else
10213 -- If prefix is an access type, the node will be transformed into an
10214 -- explicit dereference during expansion. The type of the node is the
10215 -- designated type of that of the prefix.
10220 else
10224 -- Set flag for expander if discriminant check required on a component
10225 -- appearing within a variant.
10231 and then
10234 and then not Init_Component
10235 then
10243 -- If the prefix is a record conversion, this may be a renamed
10244 -- discriminant whose bounds differ from those of the original
10245 -- one, so we must ensure that a range check is performed.
10250 then
10254 -- Note: No Eval processing is required, because the prefix is of a
10255 -- record type, or protected type, and neither can possibly be static.
10257 -- If the record type is atomic, and the component is non-atomic, then
10258 -- this is worth a warning, since we have a situation where the access
10259 -- to the component may cause extra read/writes of the atomic array
10260 -- object, or partial word accesses, both of which may be unexpected.
10266 then
10267 Error_Msg_N
10270 Error_Msg_N
10278 -------------------
10279 -- Resolve_Shift --
10280 -------------------
10287 begin
10288 -- We do the resolution using the base type, because intermediate values
10289 -- in expressions always are of the base type, not a subtype of it.
10302 ---------------------------
10303 -- Resolve_Short_Circuit --
10304 ---------------------------
10311 begin
10312 -- Ensure all actions associated with the left operand (e.g.
10313 -- finalization of transient objects) are fully evaluated locally within
10314 -- an expression with actions. This is particularly helpful for coverage
10315 -- analysis. However this should not happen in generics or if option
10316 -- Minimize_Expression_With_Actions is set.
10319 declare
10321 begin
10329 -- Set Comes_From_Source on L to preserve warnings for unset
10330 -- reference.
10339 -- Check for issuing warning for always False assert/check, this happens
10340 -- when assertions are turned off, in which case the pragma Assert/Check
10341 -- was transformed into:
10343 -- if False and then <condition> then ...
10345 -- and we detect this pattern
10347 if Warn_On_Assertion_Failure
10354 then
10355 declare
10358 begin
10359 -- Special handling of Asssert pragma
10363 then
10364 declare
10366 Original_Node
10367 (Expression
10370 begin
10371 -- Don't warn if original condition is explicit False,
10372 -- since obviously the failure is expected in this case.
10376 then
10379 -- Issue warning. We do not want the deletion of the
10380 -- IF/AND-THEN to take this message with it. We achieve this
10381 -- by making sure that the expanded code points to the Sloc
10382 -- of the expression, not the original pragma.
10384 else
10385 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10386 -- The source location of the expression is not usually
10387 -- the best choice here. For example, it gets located on
10388 -- the last AND keyword in a chain of boolean expressiond
10389 -- AND'ed together. It is best to put the message on the
10390 -- first character of the assertion, which is the effect
10391 -- of the First_Node call here.
10393 Error_Msg_F
10395 Expression
10400 -- Similar processing for Check pragma
10404 then
10405 -- Don't want to warn if original condition is explicit False
10407 declare
10409 Original_Node
10410 (Expression
10412 begin
10415 then
10418 -- Post warning
10420 else
10421 -- Again use Error_Msg_F rather than Error_Msg_N, see
10422 -- comment above for an explanation of why we do this.
10424 Error_Msg_F
10426 Expression
10434 -- Continue with processing of short circuit
10443 -------------------
10444 -- Resolve_Slice --
10445 -------------------
10454 begin
10457 -- Use the context type to select the prefix that yields the correct
10458 -- array type.
10460 declare
10467 begin
10475 then
10483 else
10488 else
10499 else
10509 -- If the prefix is an access to an unconstrained array, we must use
10510 -- the actual subtype of the object to perform the index checks. The
10511 -- object denoted by the prefix is implicit in the node, so we build
10512 -- an explicit representation for it in order to compute the actual
10513 -- subtype.
10518 declare
10522 begin
10533 then
10536 -- If the name is a selected component that depends on discriminants,
10537 -- build an actual subtype for it. This can happen only when the name
10538 -- itself is overloaded; otherwise the actual subtype is created when
10539 -- the selected component is analyzed.
10542 and then Full_Analysis
10544 then
10545 declare
10548 begin
10553 -- Maybe this should just be "else", instead of checking for the
10554 -- specific case of slice??? This is needed for the case where the
10555 -- prefix is an Image attribute, which gets expanded to a slice, and so
10556 -- has a constrained subtype which we want to use for the slice range
10557 -- check applied below (the range check won't get done if the
10558 -- unconstrained subtype of the 'Image is used).
10564 -- Obtain the type of the array index
10568 else
10572 -- If name was overloaded, set slice type correctly now
10576 -- Handle the generation of a range check that compares the array index
10577 -- against the discrete_range. The check is not applied to internally
10578 -- built nodes associated with the expansion of dispatch tables. Check
10579 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10580 -- the unit.
10582 if Tagged_Type_Expansion
10588 then
10591 -- The discrete_range is specified by a subtype indication. Create a
10592 -- shallow copy and inherit the type, parent and source location from
10593 -- the discrete_range. This ensures that the range check is inserted
10594 -- relative to the slice and that the runtime exception points to the
10595 -- proper construct.
10604 -- The discrete_range is a regular range. Resolve the bounds and remove
10605 -- their side effects.
10607 else
10624 -- Check bad use of type with predicates
10626 declare
10629 begin
10632 then
10634 else
10639 Bad_Predicated_Subtype_Use
10644 -- Otherwise here is where we check suspicious indexes
10655 ----------------------------
10656 -- Resolve_String_Literal --
10657 ----------------------------
10668 begin
10669 -- For a string appearing in a concatenation, defer creation of the
10670 -- string_literal_subtype until the end of the resolution of the
10671 -- concatenation, because the literal may be constant-folded away. This
10672 -- is a useful optimization for long concatenation expressions.
10674 -- If the string is an aggregate built for a single character (which
10675 -- happens in a non-static context) or a is null string to which special
10676 -- checks may apply, we build the subtype. Wide strings must also get a
10677 -- string subtype if they come from a one character aggregate. Strings
10678 -- generated by attributes might be static, but it is often hard to
10679 -- determine whether the enclosing context is static, so we generate
10680 -- subtypes for them as well, thus losing some rarer optimizations ???
10681 -- Same for strings that come from a static conversion.
10683 Need_Check :=
10692 -- If the resolving type is itself a string literal subtype, we can just
10693 -- reuse it, since there is no point in creating another.
10699 and then not Need_Check
10701 N_Attribute_Reference,
10702 N_Qualified_Expression,
10703 N_Type_Conversion)
10704 then
10707 -- Do not generate a string literal subtype for the default expression
10708 -- of a formal parameter in GNATprove mode. This is because the string
10709 -- subtype is associated with the freezing actions of the subprogram,
10710 -- however freezing is disabled in GNATprove mode and as a result the
10711 -- subtype is unavailable.
10713 elsif GNATprove_Mode
10715 then
10718 -- Otherwise we must create a string literal subtype. Note that the
10719 -- whole idea of string literal subtypes is simply to avoid the need
10720 -- for building a full fledged array subtype for each literal.
10722 else
10728 or else Need_Check
10729 then
10736 then
10742 -- The validity of a null string has been checked in the call to
10743 -- Eval_String_Literal.
10748 -- Always accept string literal with component type Any_Character, which
10749 -- occurs in error situations and in comparisons of literals, both of
10750 -- which should accept all literals.
10755 -- If the type is bit-packed, then we always transform the string
10756 -- literal into a full fledged aggregate.
10761 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10763 else
10764 -- For Standard.Wide_Wide_String, or any other type whose component
10765 -- type is Standard.Wide_Wide_Character, we know that all the
10766 -- characters in the string must be acceptable, since the parser
10767 -- accepted the characters as valid character literals.
10772 -- For the case of Standard.String, or any other type whose component
10773 -- type is Standard.Character, we must make sure that there are no
10774 -- wide characters in the string, i.e. that it is entirely composed
10775 -- of characters in range of type Character.
10777 -- If the string literal is the result of a static concatenation, the
10778 -- test has already been performed on the components, and need not be
10779 -- repeated.
10783 then
10787 -- If we are out of range, post error. This is one of the
10788 -- very few places that we place the flag in the middle of
10789 -- a token, right under the offending wide character. Not
10790 -- quite clear if this is right wrt wide character encoding
10791 -- sequences, but it's only an error message.
10793 Error_Msg
10800 -- For the case of Standard.Wide_String, or any other type whose
10801 -- component type is Standard.Wide_Character, we must make sure that
10802 -- there are no wide characters in the string, i.e. that it is
10803 -- entirely composed of characters in range of type Wide_Character.
10805 -- If the string literal is the result of a static concatenation,
10806 -- the test has already been performed on the components, and need
10807 -- not be repeated.
10811 then
10815 -- If we are out of range, post error. This is one of the
10816 -- very few places that we place the flag in the middle of
10817 -- a token, right under the offending wide character.
10819 -- This is not quite right, because characters in general
10820 -- will take more than one character position ???
10822 Error_Msg
10829 -- If the root type is not a standard character, then we will convert
10830 -- the string into an aggregate and will let the aggregate code do
10831 -- the checking. Standard Wide_Wide_Character is also OK here.
10833 else
10837 -- See if the component type of the array corresponding to the string
10838 -- has compile time known bounds. If yes we can directly check
10839 -- whether the evaluation of the string will raise constraint error.
10840 -- Otherwise we need to transform the string literal into the
10841 -- corresponding character aggregate and let the aggregate code do
10842 -- the checking. We use the same transformation if the component
10843 -- type has a static predicate, which will be applied to each
10844 -- character when the aggregate is resolved.
10848 -- Check for the case of full range, where we are definitely OK
10854 -- Here the range is not the complete base type range, so check
10856 declare
10864 begin
10867 then
10873 then
10874 Apply_Compile_Time_Constraint_Error
10876 CE_Range_Check_Failed,
10889 -- If we got here we meed to transform the string literal into the
10890 -- equivalent qualified positional array aggregate. This is rather
10891 -- heavy artillery for this situation, but it is hard work to avoid.
10893 declare
10898 begin
10899 -- Build the character literals, we give them source locations that
10900 -- correspond to the string positions, which is a bit tricky given
10901 -- the possible presence of wide character escape sequences.
10915 -- Should we have a call to Skip_Wide here ???
10917 -- ??? else
10918 -- Skip_Wide (P);
10926 Expression =>
10933 -------------------------
10934 -- Resolve_Target_Name --
10935 -------------------------
10938 begin
10942 -----------------------------
10943 -- Resolve_Type_Conversion --
10944 -----------------------------
10956 -- Set to False to suppress cases where we want to suppress the test
10957 -- for redundancy to avoid possible false positives on this warning.
10959 begin
10960 if not Conv_OK
10962 then
10966 -- If the Operand Etype is Universal_Fixed, then the conversion is
10967 -- never redundant. We need this check because by the time we have
10968 -- finished the rather complex transformation, the conversion looks
10969 -- redundant when it is not.
10974 -- If the operand is marked as Any_Fixed, then special processing is
10975 -- required. This is also a case where we suppress the test for a
10976 -- redundant conversion, since most certainly it is not redundant.
10981 -- Mixed-mode operation involving a literal. Context must be a fixed
10982 -- type which is applied to the literal subsequently.
10984 -- Multiplication and division involving two fixed type operands must
10985 -- yield a universal real because the result is computed in arbitrary
10986 -- precision.
10992 then
10998 or else
11000 then
11001 -- Return if expression is ambiguous
11006 -- If nothing else, the available fixed type is Duration
11008 else
11012 -- Resolve the real operand with largest available precision
11016 else
11022 -- If the operand is a literal (it could be a non-static and
11023 -- illegal exponentiation) check whether the use of Duration
11024 -- is potentially inaccurate.
11029 then
11030 Error_Msg_N
11033 Error_Msg_N
11040 then
11043 else
11052 -- In SPARK, a type conversion between array types should be restricted
11053 -- to types which have matching static bounds.
11055 -- Protect call to Matching_Static_Array_Bounds to avoid costly
11056 -- operation if not needed.
11063 then
11064 Check_SPARK_05_Restriction
11068 -- In formal mode, the operand of an ancestor type conversion must be an
11069 -- object (not an expression).
11077 then
11083 -- Note: we do the Eval_Type_Conversion call before applying the
11084 -- required checks for a subtype conversion. This is important, since
11085 -- both are prepared under certain circumstances to change the type
11086 -- conversion to a constraint error node, but in the case of
11087 -- Eval_Type_Conversion this may reflect an illegality in the static
11088 -- case, and we would miss the illegality (getting only a warning
11089 -- message), if we applied the type conversion checks first.
11093 -- Even when evaluation is not possible, we may be able to simplify the
11094 -- conversion or its expression. This needs to be done before applying
11095 -- checks, since otherwise the checks may use the original expression
11096 -- and defeat the simplifications. This is specifically the case for
11097 -- elimination of the floating-point Truncation attribute in
11098 -- float-to-int conversions.
11102 -- If after evaluation we still have a type conversion, then we may need
11103 -- to apply checks required for a subtype conversion.
11105 -- Skip these type conversion checks if universal fixed operands
11106 -- operands involved, since range checks are handled separately for
11107 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
11113 then
11117 -- Issue warning for conversion of simple object to its own type. We
11118 -- have to test the original nodes, since they may have been rewritten
11119 -- by various optimizations.
11123 -- Here we test for a redundant conversion if the warning mode is
11124 -- active (and was not locally reset), and we have a type conversion
11125 -- from source not appearing in a generic instance.
11127 if Test_Redundant
11130 and then not In_Instance
11131 then
11135 -- If the node is part of a larger expression, the Target_Type
11136 -- may not be the original type of the node if the context is a
11137 -- condition. Recover original type to see if conversion is needed.
11141 then
11145 -- If we have an entity name, then give the warning if the entity
11146 -- is the right type, or if it is a loop parameter covered by the
11147 -- original type (that's needed because loop parameters have an
11148 -- odd subtype coming from the bounds).
11151 and then
11153 or else
11157 -- If not an entity, then type of expression must match
11160 then
11161 -- One more check, do not give warning if the analyzed conversion
11162 -- has an expression with non-static bounds, and the bounds of the
11163 -- target are static. This avoids junk warnings in cases where the
11164 -- conversion is necessary to establish staticness, for example in
11165 -- a case statement.
11169 then
11172 -- Finally, if this type conversion occurs in a context requiring
11173 -- a prefix, and the expression is a qualified expression then the
11174 -- type conversion is not redundant, since a qualified expression
11175 -- is not a prefix, whereas a type conversion is. For example, "X
11176 -- := T'(Funx(...)).Y;" is illegal because a selected component
11177 -- requires a prefix, but a type conversion makes it legal: "X :=
11178 -- T(T'(Funx(...))).Y;"
11180 -- In Ada 2012, a qualified expression is a name, so this idiom is
11181 -- no longer needed, but we still suppress the warning because it
11182 -- seems unfriendly for warnings to pop up when you switch to the
11183 -- newer language version.
11187 N_Indexed_Component,
11188 N_Selected_Component,
11189 N_Slice,
11190 N_Explicit_Dereference)
11191 then
11194 -- Never warn on conversion to Long_Long_Integer'Base since
11195 -- that is most likely an artifact of the extended overflow
11196 -- checking and comes from complex expanded code.
11201 -- Here we give the redundant conversion warning. If it is an
11202 -- entity, give the name of the entity in the message. If not,
11203 -- just mention the expression.
11205 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11207 else
11210 Error_Msg_NE -- CODEFIX
11213 else
11214 Error_Msg_NE
11222 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11223 -- No need to perform any interface conversion if the type of the
11224 -- expression coincides with the target type.
11227 and then Expander_Active
11229 then
11230 declare
11234 begin
11235 -- If the type of the operand is a limited view, use nonlimited
11236 -- view when available. If it is a class-wide type, recover the
11237 -- class-wide type of the nonlimited view.
11241 then
11257 -- Conversion from interface type
11261 -- Ada 2005 (AI-217): Handle entities from limited views
11265 Error_Msg_NE -- CODEFIX
11268 Error_Msg_N
11270 N);
11273 and then not
11276 then
11278 Error_Msg_NE -- CODEFIX
11281 Error_Msg_N
11283 N);
11285 else
11289 -- Conversion to interface type
11293 -- Handle subtypes
11300 or else Interface_Present_In_Ancestor
11303 then
11305 else
11308 Error_Msg_N
11316 -- Ada 2012: once the type conversion is resolved, check whether the
11317 -- operand statisfies the static predicate of the target type.
11323 -- If at this stage we have a real to integer conversion, make sure that
11324 -- the Do_Range_Check flag is set, because such conversions in general
11325 -- need a range check. We only need this if expansion is off.
11326 -- In GNATprove mode, we only do that when converting from fixed-point
11327 -- (as floating-point to integer conversions are now handled in
11328 -- GNATprove mode).
11331 and then not Expander_Active
11336 then
11340 -- Generating C code a type conversion of an access to constrained
11341 -- array type to access to unconstrained array type involves building
11342 -- a fat pointer which in general cannot be generated on the fly. We
11343 -- remove side effects in order to store the result of the conversion
11344 -- into a temporary.
11346 if Modify_Tree_For_C
11353 then
11358 ----------------------
11359 -- Resolve_Unary_Op --
11360 ----------------------
11369 begin
11372 Check_SPARK_05_Restriction
11376 -- Deal with intrinsic unary operators
11382 then
11387 -- Deal with universal cases
11390 or else
11392 then
11399 -- Generate warning for expressions like abs (x mod 2)
11401 if Warn_On_Redundant_Constructs
11403 then
11407 Error_Msg_N -- CODEFIX
11412 -- Deal with reference generation
11419 -- Set overflow checking bit. Much cleverer code needed here eventually
11420 -- and perhaps the Resolve routines should be separated for the various
11421 -- arithmetic operations, since they will need different processing ???
11429 -- Generate warning for expressions like -5 mod 3 for integers. No need
11430 -- to worry in the floating-point case, since parens do not affect the
11431 -- result so there is no point in giving in a warning.
11433 declare
11442 begin
11443 if Warn_On_Questionable_Missing_Parens
11447 then
11450 -- We are looking for cases where the right operand is not
11451 -- parenthesized, and is a binary operator, multiply, divide, or
11452 -- mod. These are the cases where the grouping can affect results.
11456 then
11457 -- For mod, we always give the warning, since the value is
11458 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11459 -- -(5 mod 315)). But for the other cases, the only concern is
11460 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11461 -- overflows, but (-2) * 64 does not). So we try to give the
11462 -- message only when overflow is possible.
11466 then
11471 else
11477 else
11481 -- Note that the test below is deliberately excluding the
11482 -- largest negative number, since that is a potentially
11483 -- troublesome case (e.g. -2 * x, where the result is the
11484 -- largest negative integer has an overflow with 2 * x).
11491 -- For the multiplication case, the only case we have to worry
11492 -- about is when (-a)*b is exactly the largest negative number
11493 -- so that -(a*b) can cause overflow. This can only happen if
11494 -- a is a power of 2, and more generally if any operand is a
11495 -- constant that is not a power of 2, then the parentheses
11496 -- cannot affect whether overflow occurs. We only bother to
11497 -- test the left most operand
11499 -- Loop looking at left operands for one that has known value
11506 -- Operand value of 0 or 1 skips warning
11511 -- Otherwise check power of 2, if power of 2, warn, if
11512 -- anything else, skip warning.
11514 else
11518 else
11527 -- Keep looking at left operands
11532 -- For rem or "/" we can only have a problematic situation
11533 -- if the divisor has a value of minus one or one. Otherwise
11534 -- overflow is impossible (divisor > 1) or we have a case of
11535 -- division by zero in any case.
11540 then
11544 -- If we fall through warning should be issued
11546 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11548 Error_Msg_N
11555 ----------------------------------
11556 -- Resolve_Unchecked_Expression --
11557 ----------------------------------
11559 procedure Resolve_Unchecked_Expression
11562 is
11563 begin
11568 ---------------------------------------
11569 -- Resolve_Unchecked_Type_Conversion --
11570 ---------------------------------------
11572 procedure Resolve_Unchecked_Type_Conversion
11575 is
11581 begin
11582 -- Resolve operand using its own type
11586 -- In an inlined context, the unchecked conversion may be applied
11587 -- to a literal, in which case its type is the type of the context.
11588 -- (In other contexts conversions cannot apply to literals).
11590 if In_Inlined_Body
11594 then
11602 ------------------------------
11603 -- Rewrite_Operator_As_Call --
11604 ------------------------------
11611 begin
11618 New_N :=
11629 ------------------------------
11630 -- Rewrite_Renamed_Operator --
11631 ------------------------------
11633 procedure Rewrite_Renamed_Operator
11637 is
11642 begin
11643 -- Do not perform this transformation within a pre/postcondition,
11644 -- because the expression will be reanalyzed, and the transformation
11645 -- might affect the visibility of the operator, e.g. in an instance.
11646 -- Note that fully analyzed and expanded pre/postconditions appear as
11647 -- pragma Check equivalents.
11653 -- Likewise when an expression function is being preanalyzed, since the
11654 -- expression will be reanalyzed as part of the generated body.
11657 declare
11659 begin
11662 N_Expression_Function
11663 then
11669 -- Rewrite the operator node using the real operator, not its renaming.
11670 -- Exclude user-defined intrinsic operations of the same name, which are
11671 -- treated separately and rewritten as calls.
11680 -- Indicate that both the original entity and its renaming are
11681 -- referenced at this point.
11692 -- If the context type is private, add the appropriate conversions so
11693 -- that the operator is applied to the full view. This is done in the
11694 -- routines that resolve intrinsic operators.
11698 when N_Op_Add
11699 | N_Op_Divide
11700 | N_Op_Expon
11701 | N_Op_Mod
11702 | N_Op_Multiply
11703 | N_Op_Rem
11704 | N_Op_Subtract
11705 =>
11708 when N_Op_Abs
11709 | N_Op_Minus
11710 | N_Op_Plus
11711 =>
11721 -- Operator renames a user-defined operator of the same name. Use the
11722 -- original operator in the node, which is the one Gigi knows about.
11729 -----------------------
11730 -- Set_Slice_Subtype --
11731 -----------------------
11733 -- Build an implicit subtype declaration to represent the type delivered by
11734 -- the slice. This is an abbreviated version of an array subtype. We define
11735 -- an index subtype for the slice, using either the subtype name or the
11736 -- discrete range of the slice. To be consistent with index usage elsewhere
11737 -- we create a list header to hold the single index. This list is not
11738 -- otherwise attached to the syntax tree.
11749 begin
11755 else
11756 -- We force the evaluation of a range. This is definitely needed in
11757 -- the renamed case, and seems safer to do unconditionally. Note in
11758 -- any case that since we will create and insert an Itype referring
11759 -- to this range, we must make sure any side effect removal actions
11760 -- are inserted before the Itype definition.
11766 -- If the discrete range is given by a subtype indication, the
11767 -- type of the slice is the base of the subtype mark.
11770 declare
11772 begin
11781 -- Take a new copy of Drange (where bounds have been rewritten to
11782 -- reference side-effect-free names). Using a separate tree ensures
11783 -- that further expansion (e.g. while rewriting a slice assignment
11784 -- into a FOR loop) does not attempt to remove side effects on the
11785 -- bounds again (which would cause the bounds in the index subtype
11786 -- definition to refer to temporaries before they are defined) (the
11787 -- reason is that some names are considered side effect free here
11788 -- for the subtype, but not in the context of a loop iteration
11789 -- scheme).
11810 -- The Etype of the existing Slice node is reset to this slice subtype.
11811 -- Its bounds are obtained from its first index.
11815 -- For bit-packed slice subtypes, freeze immediately (except in the case
11816 -- of being in a "spec expression" where we never freeze when we first
11817 -- see the expression).
11822 -- For all other cases insert an itype reference in the slice's actions
11823 -- so that the itype is frozen at the proper place in the tree (i.e. at
11824 -- the point where actions for the slice are analyzed). Note that this
11825 -- is different from freezing the itype immediately, which might be
11826 -- premature (e.g. if the slice is within a transient scope). This needs
11827 -- to be done only if expansion is enabled.
11834 --------------------------------
11835 -- Set_String_Literal_Subtype --
11836 --------------------------------
11844 begin
11856 -- The low bound is set from the low bound of the corresponding index
11857 -- type. Note that we do not store the high bound in the string literal
11858 -- subtype, but it can be deduced if necessary from the length and the
11859 -- low bound.
11864 -- If the lower bound is not static we create a range for the string
11865 -- literal, using the index type and the known length of the literal.
11866 -- The index type is not necessarily Positive, so the upper bound is
11867 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11869 else
11870 declare
11876 Prefix =>
11880 Left_Opnd =>
11883 Prefix =>
11885 Expressions =>
11887 Right_Opnd =>
11896 begin
11898 Set_String_Literal_Low_Bound
11901 else
11902 -- If the index type is an enumeration type, build bounds
11903 -- expression with attributes.
11905 Set_String_Literal_Low_Bound
11909 Prefix =>
11916 -- Build bona fide subtype for the string, and wrap it in an
11917 -- unchecked conversion, because the back end expects the
11918 -- String_Literal_Subtype to have a static lower bound.
11920 Index_Subtype :=
11927 -- In this context, the Index_Type may already have a constraint,
11928 -- so use common base type on string subtype. The base type may
11929 -- be used when generating attributes of the string, for example
11930 -- in the context of a slice assignment.
11955 ------------------------------
11956 -- Simplify_Type_Conversion --
11957 ------------------------------
11960 begin
11962 declare
11967 begin
11968 -- Special processing if the conversion is the expression of a
11969 -- Rounding or Truncation attribute reference. In this case we
11970 -- replace:
11972 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11974 -- by
11976 -- ityp (x)
11978 -- with the Float_Truncate flag set to False or True respectively,
11979 -- which is more efficient.
11982 and then
11988 Name_Truncation)
11989 then
11990 declare
11993 begin
12003 -----------------------------
12004 -- Unique_Fixed_Point_Type --
12005 -----------------------------
12009 -- Give error messages for true ambiguity. Messages are posted on node
12010 -- N, and entities T1, T2 are the possible interpretations.
12012 -----------------------
12013 -- Fixed_Point_Error --
12014 -----------------------
12017 begin
12023 -- Local variables
12031 -- Start of processing for Unique_Fixed_Point_Type
12033 begin
12034 -- The operations on Duration are visible, so Duration is always a
12035 -- possible interpretation.
12039 -- Look for fixed-point types in enclosing scopes
12048 then
12052 else
12063 -- Look for visible fixed type declarations in the context
12074 then
12078 else
12093 else
12094 -- When the context is a type conversion, issue the warning on the
12095 -- expression of the conversion because it is the actual operation.
12099 else
12103 Error_Msg_NE
12110 ----------------------
12111 -- Valid_Conversion --
12112 ----------------------
12114 function Valid_Conversion
12119 is
12124 function Conversion_Check
12127 -- Little routine to post Msg if Valid is False, returns Valid value
12130 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
12132 procedure Conversion_Error_NE
12136 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
12139 -- Return True if expression is within an instance but is not in one of
12140 -- the actuals of the instantiation. Type conversions within an instance
12141 -- are not rechecked because type visbility may lead to spurious errors,
12142 -- but conversions in an actual for a formal object must be checked.
12144 function Valid_Tagged_Conversion
12147 -- Specifically test for validity of tagged conversions
12150 -- Check index and component conformance, and accessibility levels if
12151 -- the component types are anonymous access types (Ada 2005).
12153 ----------------------
12154 -- Conversion_Check --
12155 ----------------------
12157 function Conversion_Check
12160 is
12161 begin
12162 if not Valid
12164 -- A generic unit has already been analyzed and we have verified
12165 -- that a particular conversion is OK in that context. Since the
12166 -- instance is reanalyzed without relying on the relationships
12167 -- established during the analysis of the generic, it is possible
12168 -- to end up with inconsistent views of private types. Do not emit
12169 -- the error message in such cases. The rest of the machinery in
12170 -- Valid_Conversion still ensures the proper compatibility of
12171 -- target and operand types.
12173 and then not In_Instance_Code
12174 then
12181 ------------------------
12182 -- Conversion_Error_N --
12183 ------------------------
12186 begin
12192 -------------------------
12193 -- Conversion_Error_NE --
12194 -------------------------
12196 procedure Conversion_Error_NE
12200 is
12201 begin
12207 ----------------------
12208 -- In_Instance_Code --
12209 ----------------------
12214 begin
12218 else
12222 -- The expression is part of an actual object if it appears in
12223 -- the generated object declaration in the instance.
12227 then
12230 else
12231 exit when
12240 -- Otherwise the expression appears within the instantiated unit
12246 ----------------------------
12247 -- Valid_Array_Conversion --
12248 ----------------------------
12265 begin
12266 -- Error if wrong number of dimensions
12268 if
12270 then
12271 Conversion_Error_N
12275 -- Number of dimensions matches
12277 else
12278 -- Loop through indexes of the two arrays
12286 -- Error if index types are incompatible
12292 then
12293 Conversion_Error_N
12295 Operand);
12303 -- If component types have same base type, all set
12308 -- Here if base types of components are not the same. The only
12309 -- time this is allowed is if we have anonymous access types.
12311 -- The conversion of arrays of anonymous access types can lead
12312 -- to dangling pointers. AI-392 formalizes the accessibility
12313 -- checks that must be applied to such conversions to prevent
12314 -- out-of-scope references.
12316 elsif Ekind_In
12318 E_Anonymous_Access_Subprogram_Type)
12320 and then
12322 then
12325 then
12328 Conversion_Error_N
12338 -- Conversion not allowed because of accessibility levels
12340 else
12341 Conversion_Error_N
12347 else
12351 -- All other cases where component base types do not match
12353 else
12354 Conversion_Error_N
12356 Operand);
12360 -- Check that component subtypes statically match. For numeric
12361 -- types this means that both must be either constrained or
12362 -- unconstrained. For enumeration types the bounds must match.
12363 -- All of this is checked in Subtypes_Statically_Match.
12365 if not Subtypes_Statically_Match
12367 then
12368 Conversion_Error_N
12377 -----------------------------
12378 -- Valid_Tagged_Conversion --
12379 -----------------------------
12381 function Valid_Tagged_Conversion
12384 is
12385 begin
12386 -- Upward conversions are allowed (RM 4.6(22))
12390 then
12393 -- Downward conversion are allowed if the operand is class-wide
12394 -- (RM 4.6(23)).
12398 then
12403 then
12404 return
12408 -- Ada 2005 (AI-251): The conversion to/from interface types is
12409 -- always valid. The types involved may be class-wide (sub)types.
12413 then
12416 -- If the operand is a class-wide type obtained through a limited_
12417 -- with clause, and the context includes the nonlimited view, use
12418 -- it to determine whether the conversion is legal.
12424 then
12429 then
12432 else
12433 Conversion_Error_NE
12440 -- Start of processing for Valid_Conversion
12442 begin
12446 declare
12454 begin
12455 -- Remove procedure calls, which syntactically cannot appear in
12456 -- this context, but which cannot be removed by type checking,
12457 -- because the context does not impose a type.
12459 -- The node may be labelled overloaded, but still contain only one
12460 -- interpretation because others were discarded earlier. If this
12461 -- is the case, retain the single interpretation if legal.
12469 then
12470 -- More than one candidate interpretation is available
12478 -- When compiling for a system where Address is of a visible
12479 -- integer type, spurious ambiguities can be produced when
12480 -- arithmetic operations have a literal operand and return
12481 -- System.Address or a descendant of it. These ambiguities
12482 -- are usually resolved by the context, but for conversions
12483 -- there is no context type and the removal of the spurious
12484 -- operations must be done explicitly here.
12486 if not Address_Is_Private
12488 then
12513 Conversion_Error_N
12516 -- If the interpretation involves a standard operator, use
12517 -- the location of the type, which may be user-defined.
12521 else
12525 Conversion_Error_N -- CODEFIX
12530 else
12534 Conversion_Error_N -- CODEFIX
12546 -- Deal with conversion of integer type to address if the pragma
12547 -- Allow_Integer_Address is in effect. We convert the conversion to
12548 -- an unchecked conversion in this case and we are all done.
12556 -- If we are within a child unit, check whether the type of the
12557 -- expression has an ancestor in a parent unit, in which case it
12558 -- belongs to its derivation class even if the ancestor is private.
12559 -- See RM 7.3.1 (5.2/3).
12563 -- Numeric types
12567 -- A universal fixed expression can be converted to any numeric type
12572 -- Also no need to check when in an instance or inlined body, because
12573 -- the legality has been established when the template was analyzed.
12574 -- Furthermore, numeric conversions may occur where only a private
12575 -- view of the operand type is visible at the instantiation point.
12576 -- This results in a spurious error if we check that the operand type
12577 -- is a numeric type.
12579 -- Note: in a previous version of this unit, the following tests were
12580 -- applied only for generated code (Comes_From_Source set to False),
12581 -- but in fact the test is required for source code as well, since
12582 -- this situation can arise in source code.
12587 -- Otherwise we need the conversion check
12589 else
12590 return Conversion_Check
12592 or else
12598 -- Array types
12604 then
12605 Conversion_Error_N
12609 else
12613 -- Ada 2005 (AI-251): Internally generated conversions of access to
12614 -- interface types added to force the displacement of the pointer to
12615 -- reference the corresponding dispatch table.
12620 then
12623 -- Ada 2005 (AI-251): Anonymous access types where target references an
12624 -- interface type.
12628 E_Anonymous_Access_Type)
12630 then
12631 -- Check the static accessibility rule of 4.6(17). Note that the
12632 -- check is not enforced when within an instance body, since the
12633 -- RM requires such cases to be caught at run time.
12635 -- If the operand is a rewriting of an allocator no check is needed
12636 -- because there are no accessibility issues.
12644 then
12645 -- In an instance, this is a run-time check, but one we know
12646 -- will fail, so generate an appropriate warning. The raise
12647 -- will be generated by Expand_N_Type_Conversion.
12651 Conversion_Error_N
12653 Operand);
12656 else
12657 Conversion_Error_N
12659 Operand);
12663 -- Special accessibility checks are needed in the case of access
12664 -- discriminants declared for a limited type.
12668 then
12669 -- When the operand is a selected access discriminant the check
12670 -- needs to be made against the level of the object denoted by
12671 -- the prefix of the selected name (Object_Access_Level handles
12672 -- checking the prefix of the operand for this case).
12677 then
12678 -- In an instance, this is a run-time check, but one we know
12679 -- will fail, so generate an appropriate warning. The raise
12680 -- will be generated by Expand_N_Type_Conversion.
12684 Conversion_Error_N
12689 -- Real error if not in instance body
12691 else
12692 Conversion_Error_N
12699 -- The case of a reference to an access discriminant from
12700 -- within a limited type declaration (which will appear as
12701 -- a discriminal) is always illegal because the level of the
12702 -- discriminant is considered to be deeper than any (nameable)
12703 -- access type.
12707 and then
12710 then
12711 Conversion_Error_N
12713 Operand);
12721 -- General and anonymous access types
12724 E_Anonymous_Access_Type)
12725 and then
12726 Conversion_Check
12728 and then not
12730 E_Access_Protected_Subprogram_Type),
12732 then
12735 then
12736 Conversion_Error_N
12741 -- Check the static accessibility rule of 4.6(17). Note that the
12742 -- check is not enforced when within an instance body, since the RM
12743 -- requires such cases to be caught at run time.
12748 N_Object_Declaration
12749 then
12750 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12751 -- conversions from an anonymous access type to a named general
12752 -- access type. Such conversions are not allowed in the case of
12753 -- access parameters and stand-alone objects of an anonymous
12754 -- access type. The implicit conversion case is recognized by
12755 -- testing that Comes_From_Source is False and that it's been
12756 -- rewritten. The Comes_From_Source test isn't sufficient because
12757 -- nodes in inlined calls to predefined library routines can have
12758 -- Comes_From_Source set to False. (Is there a better way to test
12759 -- for implicit conversions???)
12766 then
12769 -- Implicit conversions aren't allowed for objects of an
12770 -- anonymous access type, since such objects have nonstatic
12771 -- levels in Ada 2012.
12774 N_Object_Declaration
12775 then
12776 Conversion_Error_N
12781 -- Implicit conversions aren't allowed for anonymous access
12782 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12783 -- is done to exclude anonymous access results.
12787 N_Function_Specification,
12788 N_Procedure_Specification)
12789 then
12790 Conversion_Error_N
12795 -- This is a case where there's an enclosing object whose
12796 -- to which the "statically deeper than" relationship does
12797 -- not apply (such as an access discriminant selected from
12798 -- a dereference of an access parameter).
12802 then
12803 Conversion_Error_N
12808 -- In other cases, the level of the operand's type must be
12809 -- statically less deep than that of the target type, else
12810 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12814 then
12815 Conversion_Error_N
12824 then
12825 -- In an instance, this is a run-time check, but one we know
12826 -- will fail, so generate an appropriate warning. The raise
12827 -- will be generated by Expand_N_Type_Conversion.
12831 Conversion_Error_N
12833 Operand);
12836 -- If not in an instance body, this is a real error
12838 else
12839 -- Avoid generation of spurious error message
12842 Conversion_Error_N
12844 Operand);
12850 -- Special accessibility checks are needed in the case of access
12851 -- discriminants declared for a limited type.
12855 then
12856 -- When the operand is a selected access discriminant the check
12857 -- needs to be made against the level of the object denoted by
12858 -- the prefix of the selected name (Object_Access_Level handles
12859 -- checking the prefix of the operand for this case).
12864 then
12865 -- In an instance, this is a run-time check, but one we know
12866 -- will fail, so generate an appropriate warning. The raise
12867 -- will be generated by Expand_N_Type_Conversion.
12871 Conversion_Error_N
12876 -- If not in an instance body, this is a real error
12878 else
12879 Conversion_Error_N
12886 -- The case of a reference to an access discriminant from
12887 -- within a limited type declaration (which will appear as
12888 -- a discriminal) is always illegal because the level of the
12889 -- discriminant is considered to be deeper than any (nameable)
12890 -- access type.
12893 and then
12896 then
12897 Conversion_Error_N
12899 Operand);
12905 -- In the presence of limited_with clauses we have to use nonlimited
12906 -- views, if available.
12910 -- Helper function to handle limited views
12912 --------------------------
12913 -- Full_Designated_Type --
12914 --------------------------
12919 begin
12920 -- Handle the limited view of a type
12924 then
12926 else
12931 -- Local Declarations
12939 -- Start of processing for Check_Limited
12941 begin
12945 else
12947 Conversion_Error_NE
12952 -- Ada 2005 AI-384: legality rule is symmetric in both
12953 -- designated types. The conversion is legal (with possible
12954 -- constraint check) if either designated type is
12955 -- unconstrained.
12958 or else
12960 and then
12963 then
12964 -- Special case, if Value_Size has been used to make the
12965 -- sizes different, the conversion is not allowed even
12966 -- though the subtypes statically match.
12971 then
12972 Conversion_Error_NE
12975 Conversion_Error_NE
12980 -- Normal case where conversion is allowed
12982 else
12986 else
12987 Error_Msg_NE
12995 -- Access to subprogram types. If the operand is an access parameter,
12996 -- the type has a deeper accessibility that any master, and cannot be
12997 -- assigned. We must make an exception if the conversion is part of an
12998 -- assignment and the target is the return object of an extended return
12999 -- statement, because in that case the accessibility check takes place
13000 -- after the return.
13004 -- Note: this test of Opnd_Type is there to prevent entering this
13005 -- branch in the case of a remote access to subprogram type, which
13006 -- is internally represented as an E_Record_Type.
13009 then
13013 and then
13017 then
13018 Conversion_Error_N
13020 Operand);
13021 Conversion_Error_N
13024 Operand);
13026 Error_Msg_NE
13031 -- Check that the designated types are subtype conformant
13037 -- Check the static accessibility rule of 4.6(20)
13041 then
13042 Conversion_Error_N
13044 Operand);
13046 -- Check that if the operand type is declared in a generic body,
13047 -- then the target type must be declared within that same body
13048 -- (enforces last sentence of 4.6(20)).
13051 declare
13057 begin
13064 Conversion_Error_N
13073 -- Remote access to subprogram types
13077 then
13078 -- It is valid to convert from one RAS type to another provided
13079 -- that their specification statically match.
13081 -- Note: at this point, remote access to subprogram types have been
13082 -- expanded to their E_Record_Type representation, and we need to
13083 -- go back to the original access type definition using the
13084 -- Corresponding_Remote_Type attribute in order to check that the
13085 -- designated profiles match.
13090 Check_Subtype_Conformant
13093 Old_Id =>
13095 Err_Loc =>
13096 N);
13099 -- If it was legal in the generic, it's legal in the instance
13104 -- If both are tagged types, check legality of view conversions
13107 and then
13109 then
13112 -- Types derived from the same root type are convertible
13117 -- In an instance or an inlined body, there may be inconsistent views of
13118 -- the same type, or of types derived from a common root.
13121 and then
13124 then
13127 -- Special check for common access type error case
13131 then
13133 Conversion_Error_NE -- CODEFIX
13137 -- Here we have a real conversion error
13139 else
13140 -- Check for missing regular with_clause when only a limited view of
13141 -- target is available.
13144 Conversion_Error_NE
13147 Conversion_Error_NE
13152 and then In_Package_Body
13153 then
13154 Conversion_Error_NE
13156 Conversion_Error_NE
13160 else
13161 Conversion_Error_NE