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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2018, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
86 -----------------------
87 -- Local Subprograms --
88 -----------------------
90 -- Second pass (top-down) type checking and overload resolution procedures
91 -- Typ is the type required by context. These procedures propagate the
92 -- type information recursively to the descendants of N. If the node is not
93 -- overloaded, its Etype is established in the first pass. If overloaded,
94 -- the Resolve routines set the correct type. For arithmetic operators, the
95 -- Etype is the base type of the context.
97 -- Note that Resolve_Attribute is separated off in Sem_Attr
100 -- Enforce the restrictions on the use of discriminants when constraining
101 -- a component of a discriminated type (record or concurrent type).
104 -- Given a node for an operator associated with type T, check that the
105 -- operator is visible. Operators all of whose operands are universal must
106 -- be checked for visibility during resolution because their type is not
107 -- determinable based on their operands.
109 procedure Check_Fully_Declared_Prefix
112 -- Check that the type of the prefix of a dereference is not incomplete
115 -- Given a call node, N, which is known to occur immediately within the
116 -- subprogram being called, determines whether it is a detectable case of
117 -- an infinite recursion, and if so, outputs appropriate messages. Returns
118 -- True if an infinite recursion is detected, and False otherwise.
121 -- N is the node for a logical operator. If the operator is predefined, and
122 -- the root type of the operands is Standard.Boolean, then a check is made
123 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
124 -- the style check for Style_Check_Boolean_And_Or.
127 -- N is either an indexed component or a selected component. This function
128 -- returns true if the prefix refers to an object that has an address
129 -- clause (the case in which we may want to issue a warning).
132 -- Determine whether E is an access type declared by an access declaration,
133 -- and not an (anonymous) allocator type.
136 -- Utility to check whether the entity for an operator is a predefined
137 -- operator, in which case the expression is left as an operator in the
138 -- tree (else it is rewritten into a call). An instance of an intrinsic
139 -- conversion operation may be given an operator name, but is not treated
140 -- like an operator. Note that an operator that is an imported back-end
141 -- builtin has convention Intrinsic, but is expected to be rewritten into
142 -- a call, so such an operator is not treated as predefined by this
143 -- predicate.
146 -- If a default expression in entry call N depends on the discriminants
147 -- of the task, it must be replaced with a reference to the discriminant
148 -- of the task being called.
150 procedure Resolve_Op_Concat_Arg
155 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
156 -- concatenation operator. The operand is either of the array type or of
157 -- the component type. If the operand is an aggregate, and the component
158 -- type is composite, this is ambiguous if component type has aggregates.
161 -- Does the first part of the work of Resolve_Op_Concat
164 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
165 -- has been resolved. See Resolve_Op_Concat for details.
204 function Operator_Kind
207 -- Utility to map the name of an operator into the corresponding Node. Used
208 -- by other node rewriting procedures.
211 -- Resolve actuals of call, and add default expressions for missing ones.
212 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
213 -- called subprogram.
216 -- Called from Resolve_Call, when the prefix denotes an entry or element
217 -- of entry family. Actuals are resolved as for subprograms, and the node
218 -- is rebuilt as an entry call. Also called for protected operations. Typ
219 -- is the context type, which is used when the operation is a protected
220 -- function with no arguments, and the return value is indexed.
223 -- A call to a user-defined intrinsic operator is rewritten as a call to
224 -- the corresponding predefined operator, with suitable conversions. Note
225 -- that this applies only for intrinsic operators that denote predefined
226 -- operators, not ones that are intrinsic imports of back-end builtins.
229 -- Ditto, for arithmetic unary operators
232 -- If an operator node resolves to a call to a user-defined operator,
233 -- rewrite the node as a function call.
235 procedure Make_Call_Into_Operator
239 -- Inverse transformation: if an operator is given in functional notation,
240 -- then after resolving the node, transform into an operator node, so that
241 -- operands are resolved properly. Recall that predefined operators do not
242 -- have a full signature and special resolution rules apply.
244 procedure Rewrite_Renamed_Operator
248 -- An operator can rename another, e.g. in an instantiation. In that
249 -- case, the proper operator node must be constructed and resolved.
252 -- The String_Literal_Subtype is built for all strings that are not
253 -- operands of a static concatenation operation. If the argument is not
254 -- a N_String_Literal node, then the call has no effect.
257 -- Build subtype of array type, with the range specified by the slice
260 -- Called after N has been resolved and evaluated, but before range checks
261 -- have been applied. Currently simplifies a combination of floating-point
262 -- to integer conversion and Rounding or Truncation attribute.
265 -- A universal_fixed expression in an universal context is unambiguous if
266 -- there is only one applicable fixed point type. Determining whether there
267 -- is only one requires a search over all visible entities, and happens
268 -- only in very pathological cases (see 6115-006).
270 -------------------------
271 -- Ambiguous_Character --
272 -------------------------
277 begin
281 -- First the ones in Standard
286 -- Include Wide_Wide_Character in Ada 2005 mode
292 -- Now any other types that match
302 -------------------------
303 -- Analyze_And_Resolve --
304 -------------------------
307 begin
313 begin
318 -- Versions with check(s) suppressed
320 procedure Analyze_And_Resolve
324 is
327 begin
329 declare
331 begin
337 else
338 declare
340 begin
348 and then Scope_Is_Transient
349 then
350 -- This can only happen if a transient scope was created for an inner
351 -- expression, which will be removed upon completion of the analysis
352 -- of an enclosing construct. The transient scope must have the
353 -- suppress status of the enclosing environment, not of this Analyze
354 -- call.
357 Scope_Suppress;
361 procedure Analyze_And_Resolve
364 is
367 begin
369 declare
371 begin
377 else
378 declare
380 begin
389 Scope_Suppress;
393 ----------------------------
394 -- Check_Discriminant_Use --
395 ----------------------------
403 begin
404 -- Any use in a spec-expression is legal
411 -- Discriminant cannot be used to constrain a scalar type
418 then
423 -- The following check catches the unusual case where a
424 -- discriminant appears within an index constraint that is part
425 -- of a larger expression within a constraint on a component,
426 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
427 -- check case of record components, and note that a similar check
428 -- should also apply in the case of discriminant constraints
429 -- below. ???
431 -- Note that the check for N_Subtype_Declaration below is to
432 -- detect the valid use of discriminants in the constraints of a
433 -- subtype declaration when this subtype declaration appears
434 -- inside the scope of a record type (which is syntactically
435 -- illegal, but which may be created as part of derived type
436 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
437 -- for more info.
441 and then not
443 and then
445 N_Subtype_Declaration)
447 then
448 Error_Msg_N
453 -- Detect a common error:
455 -- type R (D : Positive := 100) is record
456 -- Name : String (1 .. D);
457 -- end record;
459 -- The default value causes an object of type R to be allocated
460 -- with room for Positive'Last characters. The RM does not mandate
461 -- the allocation of the maximum size, but that is what GNAT does
462 -- so we should warn the programmer that there is a problem.
471 -- Return True if type T has a large enough range that any
472 -- array whose index type covered the whole range of the type
473 -- would likely raise Storage_Error.
475 ------------------------
476 -- Large_Storage_Type --
477 ------------------------
480 begin
481 -- The type is considered large if its bounds are known at
482 -- compile time and if it requires at least as many bits as
483 -- a Positive to store the possible values.
487 and then
492 -- Start of processing for Check_Large
494 begin
495 -- Check that the Disc has a large range
501 -- If the enclosing type is limited, we allocate only the
502 -- default value, not the maximum, and there is no need for
503 -- a warning.
509 -- Check that it is the high bound
513 then
517 -- Check the array allows a large range at this bound. First
518 -- find the array
532 -- Next, find the dimension
540 loop
549 -- Now, check the dimension has a large range
555 -- Warn about the danger
557 Error_Msg_N
567 -- Legal case is in index or discriminant constraint
570 N_Discriminant_Association)
571 then
573 Error_Msg_N
578 then
579 Error_Msg_N
585 -- Otherwise, context is an expression. It should not be within (i.e. a
586 -- subexpression of) a constraint for a component.
588 else
592 N_Subtype_Indication,
593 N_Entry_Declaration)
594 loop
600 -- If the discriminant is used in an expression that is a bound of a
601 -- scalar type, an Itype is created and the bounds are attached to
602 -- its range, not to the original subtype indication. Such use is of
603 -- course a double fault.
607 N_Derived_Type_Definition)
610 -- The constraint itself may be given by a subtype indication,
611 -- rather than by a more common discrete range.
614 and then
618 then
619 Error_Msg_N
625 --------------------------------
626 -- Check_For_Visible_Operator --
627 --------------------------------
630 begin
632 Error_Msg_NE -- CODEFIX
634 Error_Msg_N -- CODEFIX
639 ----------------------------------
640 -- Check_Fully_Declared_Prefix --
641 ----------------------------------
643 procedure Check_Fully_Declared_Prefix
646 is
647 begin
648 -- Check that the designated type of the prefix of a dereference is
649 -- not an incomplete type. This cannot be done unconditionally, because
650 -- dereferences of private types are legal in default expressions. This
651 -- case is taken care of in Check_Fully_Declared, called below. There
652 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
654 -- This consideration also applies to similar checks for allocators,
655 -- qualified expressions, and type conversions.
657 -- An additional exception concerns other per-object expressions that
658 -- are not directly related to component declarations, in particular
659 -- representation pragmas for tasks. These will be per-object
660 -- expressions if they depend on discriminants or some global entity.
661 -- If the task has access discriminants, the designated type may be
662 -- incomplete at the point the expression is resolved. This resolution
663 -- takes place within the body of the initialization procedure, where
664 -- the discriminant is replaced by its discriminal.
668 then
671 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
672 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
673 -- Analyze_Object_Renaming, and Freeze_Entity.
679 E_Incomplete_Type
681 then
683 else
688 ------------------------------
689 -- Check_Infinite_Recursion --
690 ------------------------------
697 -- Check whether list of actuals is identical to list of formals of
698 -- called function (which is also the enclosing scope).
700 ------------------------
701 -- Same_Argument_List --
702 ------------------------
709 begin
712 else
730 -- Start of processing for Check_Infinite_Recursion
732 begin
733 -- Special case, if this is a procedure call and is a call to the
734 -- current procedure with the same argument list, then this is for
735 -- sure an infinite recursion and we insert a call to raise SE.
739 and then Same_Argument_List
740 then
741 declare
743 begin
747 then
759 -- If not that special case, search up tree, quitting if we reach a
760 -- construct (e.g. a conditional) that tells us that this is not a
761 -- case for an infinite recursion warning.
764 loop
767 -- If no parent, then we were not inside a subprogram, this can for
768 -- example happen when processing certain pragmas in a spec. Just
769 -- return False in this case.
775 -- Done if we get to subprogram body, this is definitely an infinite
776 -- recursion case if we did not find anything to stop us.
780 -- If appearing in conditional, result is false
783 N_And_Then,
784 N_Case_Expression,
785 N_Case_Statement,
786 N_If_Expression,
787 N_If_Statement)
788 then
793 then
794 -- If the call is the expression of a return statement and the
795 -- actuals are identical to the formals, it's worth a warning.
796 -- However, we skip this if there is an immediately preceding
797 -- raise statement, since the call is never executed.
799 -- Furthermore, this corresponds to a common idiom:
801 -- function F (L : Thing) return Boolean is
802 -- begin
803 -- raise Program_Error;
804 -- return F (L);
805 -- end F;
807 -- for generating a stub function
810 and then Same_Argument_List
811 then
814 -- OK, return statement is in a statement list, look for raise
816 declare
819 begin
820 -- Skip past N_Freeze_Entity nodes generated by expansion
825 loop
829 -- If no raise statement, give warning. We look at the
830 -- original node, because in the case of "raise ... with
831 -- ...", the node has been transformed into a call.
834 and then
842 else
854 ---------------------------------------
855 -- Check_No_Direct_Boolean_Operators --
856 ---------------------------------------
859 begin
862 then
863 -- Restriction only applies to original source code
870 -- Do style check (but skip if in instance, error is on template)
879 ------------------------------
880 -- Check_Parameterless_Call --
881 ------------------------------
887 -- If the prefix is of an access_to_subprogram type, the node must be
888 -- rewritten as a call. Ditto if the prefix is overloaded and all its
889 -- interpretations are access to subprograms.
891 ---------------------------
892 -- Prefix_Is_Access_Subp --
893 ---------------------------
899 begin
900 -- If the context is an attribute reference that can apply to
901 -- functions, this is never a parameterless call (RM 4.1.4(6)).
905 Name_Code_Address,
906 Name_Access)
907 then
912 return
915 else
920 then
931 -- Start of processing for Check_Parameterless_Call
933 begin
934 -- Defend against junk stuff if errors already detected
941 then
948 -- If the context expects a value, and the name is a procedure, this is
949 -- most likely a missing 'Access. Don't try to resolve the parameterless
950 -- call, error will be caught when the outer call is analyzed.
955 and then
957 N_Function_Call,
958 N_Procedure_Call_Statement)
959 then
963 -- Rewrite as call if overloadable entity that is (or could be, in the
964 -- overloaded case) a function call. If we know for sure that the entity
965 -- is an enumeration literal, we do not rewrite it.
967 -- If the entity is the name of an operator, it cannot be a call because
968 -- operators cannot have default parameters. In this case, this must be
969 -- a string whose contents coincide with an operator name. Set the kind
970 -- of the node appropriately.
978 -- Rewrite as call if it is an explicit dereference of an expression of
979 -- a subprogram access type, and the subprogram type is not that of a
980 -- procedure or entry.
982 or else
985 -- Rewrite as call if it is a selected component which is a function,
986 -- this is the case of a call to a protected function (which may be
987 -- overloaded with other protected operations).
989 or else
992 or else
994 E_Procedure)
997 -- If one of the above three conditions is met, rewrite as call. Apply
998 -- the rewriting only once.
1000 then
1003 then
1005 -- This may be a prefixed call that was not fully analyzed, e.g.
1006 -- an actual in an instance.
1011 then
1019 -- The node is the name of the parameterless call. Preserve its
1020 -- descendants, which may be complex expressions.
1024 -- If overloaded, overload set belongs to new copy
1028 -- Change node to parameterless function call (note that the
1029 -- Parameter_Associations associations field is left set to Empty,
1030 -- its normal default value since there are no parameters)
1048 --------------------------------
1049 -- Is_Atomic_Ref_With_Address --
1050 --------------------------------
1055 begin
1059 else
1060 declare
1063 begin
1071 -----------------------------
1072 -- Is_Definite_Access_Type --
1073 -----------------------------
1077 begin
1083 ----------------------
1084 -- Is_Predefined_Op --
1085 ----------------------
1088 begin
1089 -- Predefined operators are intrinsic subprograms
1095 -- A call to a back-end builtin is never a predefined operator
1106 -----------------------------
1107 -- Make_Call_Into_Operator --
1108 -----------------------------
1110 procedure Make_Call_Into_Operator
1114 is
1129 -- If the operand is not universal, and the operator is given by an
1130 -- expanded name, verify that the operand has an interpretation with a
1131 -- type defined in the given scope of the operator.
1134 -- Find a type of the given class in package Pack that contains the
1135 -- operator.
1137 ---------------------------
1138 -- Operand_Type_In_Scope --
1139 ---------------------------
1146 begin
1150 else
1164 ---------------
1165 -- Type_In_P --
1166 ---------------
1172 -- Verify that node is not part of the type declaration for the
1173 -- candidate type, which would otherwise be invisible.
1175 -------------
1176 -- In_Decl --
1177 -------------
1183 begin
1192 else
1195 loop
1198 else
1207 -- Start of processing for Type_In_P
1209 begin
1210 -- If the context type is declared in the prefix package, this is the
1211 -- desired base type.
1216 else
1230 -- Start of processing for Make_Call_Into_Operator
1232 begin
1235 -- Ensure that the corresponding operator has the same parent as the
1236 -- original call. This guarantees that parent traversals performed by
1237 -- the ABE mechanism succeed.
1241 -- Binary operator
1251 -- Unary operator
1253 else
1259 -- If the operator is denoted by an expanded name, and the prefix is
1260 -- not Standard, but the operator is a predefined one whose scope is
1261 -- Standard, then this is an implicit_operator, inserted as an
1262 -- interpretation by the procedure of the same name. This procedure
1263 -- overestimates the presence of implicit operators, because it does
1264 -- not examine the type of the operands. Verify now that the operand
1265 -- type appears in the given scope. If right operand is universal,
1266 -- check the other operand. In the case of concatenation, either
1267 -- argument can be the component type, so check the type of the result.
1268 -- If both arguments are literals, look for a type of the right kind
1269 -- defined in the given scope. This elaborate nonsense is brought to
1270 -- you courtesy of b33302a. The type itself must be frozen, so we must
1271 -- find the type of the proper class in the given scope.
1273 -- A final wrinkle is the multiplication operator for fixed point types,
1274 -- which is defined in Standard only, and not in the scope of the
1275 -- fixed point type itself.
1280 -- If this is a package renaming, get renamed entity, which will be
1281 -- the scope of the operands if operaton is type-correct.
1287 -- If the entity being called is defined in the given package, it is
1288 -- a renaming of a predefined operator, and known to be legal.
1292 then
1295 -- Visibility does not need to be checked in an instance: if the
1296 -- operator was not visible in the generic it has been diagnosed
1297 -- already, else there is an implicit copy of it in the instance.
1305 then
1310 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1311 -- available.
1316 then
1319 else
1328 and then Is_Binary
1330 then
1336 -- Verify that the scope contains a type that corresponds to
1337 -- the given literal. Optimize the case where Pack is Standard.
1358 else
1367 else
1376 then
1379 -- If the type is defined elsewhere, and the operator is not
1380 -- defined in the given scope (by a renaming declaration, e.g.)
1381 -- then this is an error as well. If an extension of System is
1382 -- present, and the type may be defined there, Pack must be
1383 -- System itself.
1390 then
1393 else
1399 then
1406 Error_Msg_NE
1411 -- Detect a mismatch between the context type and the result type
1412 -- in the named package, which is otherwise not detected if the
1413 -- operands are universal. Check is only needed if source entity is
1414 -- an operator, not a function that renames an operator.
1421 and then not In_Instance
1422 then
1425 then
1426 -- Already checked above
1430 -- Operator may be defined in an extension of System
1435 then
1438 else
1439 -- Could we use Wrong_Type here??? (this would require setting
1440 -- Etype (N) to the actual type found where Typ was expected).
1451 else
1455 -- If this is a call to a function that renames a predefined equality,
1456 -- the renaming declaration provides a type that must be used to
1457 -- resolve the operands. This must be done now because resolution of
1458 -- the equality node will not resolve any remaining ambiguity, and it
1459 -- assumes that the first operand is not overloaded.
1464 then
1472 -- Do rewrite setting Comes_From_Source on the result if the original
1473 -- call came from source. Although it is not strictly the case that the
1474 -- operator as such comes from the source, logically it corresponds
1475 -- exactly to the function call in the source, so it should be marked
1476 -- this way (e.g. to make sure that validity checks work fine).
1478 declare
1480 begin
1485 -- If this is an arithmetic operator and the result type is private,
1486 -- the operands and the result must be wrapped in conversion to
1487 -- expose the underlying numeric type and expand the proper checks,
1488 -- e.g. on division.
1492 when N_Op_Add
1493 | N_Op_Divide
1494 | N_Op_Expon
1495 | N_Op_Mod
1496 | N_Op_Multiply
1497 | N_Op_Rem
1498 | N_Op_Subtract
1499 =>
1502 when N_Op_Abs
1503 | N_Op_Minus
1504 | N_Op_Plus
1505 =>
1511 else
1515 -- If in ASIS_Mode, propagate operand types to original actuals of
1516 -- function call, which would otherwise not be fully resolved. If
1517 -- the call has already been constant-folded, nothing to do. We
1518 -- relocate the operand nodes rather than copy them, to preserve
1519 -- original_node pointers, given that the operands themselves may
1520 -- have been rewritten. If the call was itself a rewriting of an
1521 -- operator node, nothing to do.
1523 if ASIS_Mode
1526 then
1527 declare
1535 begin
1540 -- If the original call has named associations, replace the
1541 -- explicit actual parameter in the association with the proper
1542 -- resolved operand.
1547 then
1550 else
1555 else
1562 then
1565 else
1570 else
1574 else
1578 else
1588 -------------------
1589 -- Operator_Kind --
1590 -------------------
1592 function Operator_Kind
1595 is
1598 begin
1599 -- Use CASE statement or array???
1636 else
1640 -- Unary operators
1642 else
1651 else
1659 ----------------------------
1660 -- Preanalyze_And_Resolve --
1661 ----------------------------
1666 begin
1670 -- Normally, we suppress all checks for this preanalysis. There is no
1671 -- point in processing them now, since they will be applied properly
1672 -- and in the proper location when the default expressions reanalyzed
1673 -- and reexpanded later on. We will also have more information at that
1674 -- point for possible suppression of individual checks.
1676 -- However, in SPARK mode, most expansion is suppressed, and this
1677 -- later reanalysis and reexpansion may not occur. SPARK mode does
1678 -- require the setting of checking flags for proof purposes, so we
1679 -- do the SPARK preanalysis without suppressing checks.
1681 -- This special handling for SPARK mode is required for example in the
1682 -- case of Ada 2012 constructs such as quantified expressions, which are
1683 -- expanded in two separate steps.
1687 else
1691 Expander_Mode_Restore;
1695 -- Version without context type
1700 begin
1707 Expander_Mode_Restore;
1711 ----------------------------------
1712 -- Replace_Actual_Discriminants --
1713 ----------------------------------
1720 -- Comment needed???
1722 -------------------
1723 -- Process_Discr --
1724 -------------------
1729 begin
1735 then
1751 -- Start of processing for Replace_Actual_Discriminants
1753 begin
1757 -- Allow the replacement of concurrent discriminants in GNATprove even
1758 -- though this is a light expansion activity. Note that generic units
1759 -- are not modified.
1764 else
1780 -------------
1781 -- Resolve --
1782 -------------
1798 -- Determine whether a node comes from a predefined library unit or
1799 -- Standard.
1802 -- Try and fix up a literal so that it matches its expected type. New
1803 -- literals are manufactured if necessary to avoid cascaded errors.
1806 -- Additional diagnostics when an ambiguous call has an ambiguous
1807 -- argument (typically a controlling actual).
1810 -- Called when attempt at resolving current expression fails
1812 ------------------------------------
1813 -- Comes_From_Predefined_Lib_Unit --
1814 -------------------------------------
1817 begin
1818 return
1822 --------------------
1823 -- Patch_Up_Value --
1824 --------------------
1827 begin
1844 then
1849 Char_Literal_Value =>
1865 -------------------------------
1866 -- Report_Ambiguous_Argument --
1867 -------------------------------
1874 begin
1878 then
1881 -- Could use comments on what is going on here???
1889 else
1898 -----------------------
1899 -- Resolution_Failed --
1900 -----------------------
1903 begin
1906 -- Set the type to the desired one to minimize cascaded errors. Note
1907 -- that this is an approximation and does not work in all cases.
1914 -- The caller will return without calling the expander, so we need
1915 -- to set the analyzed flag. Note that it is fine to set Analyzed
1916 -- to True even if we are in the middle of a shallow analysis,
1917 -- (see the spec of sem for more details) since this is an error
1918 -- situation anyway, and there is no point in repeating the
1919 -- analysis later (indeed it won't work to repeat it later, since
1920 -- we haven't got a clear resolution of which entity is being
1921 -- referenced.)
1927 -- Start of processing for Resolve
1929 begin
1934 -- Access attribute on remote subprogram cannot be used for a non-remote
1935 -- access-to-subprogram type.
1939 Name_Unrestricted_Access,
1940 Name_Unchecked_Access)
1946 then
1947 Error_Msg_N
1953 -- If the context is a Remote_Access_To_Subprogram, access attributes
1954 -- must be resolved with the corresponding fat pointer. There is no need
1955 -- to check for the attribute name since the return type of an
1956 -- attribute is never a remote type.
1961 then
1962 declare
1970 begin
1971 -- Check that Typ is a remote access-to-subprogram type
1975 -- Prefix (N) must statically denote a remote subprogram
1976 -- declared in a package specification.
1980 Attr = Attribute_Unrestricted_Access
1981 then
1996 or else
1998 then
2000 Error_Msg_N
2002 N);
2005 -- If we are generating code in distributed mode, perform
2006 -- semantic checks against corresponding remote entities.
2008 if Expander_Active
2010 then
2011 Check_Subtype_Conformant
2013 Old_Id => Designated_Type
2039 then
2044 -- Return if already analyzed
2051 -- Any case of Any_Type as the Etype value means that we had a
2052 -- previous error.
2061 -- The resolution of an Expression_With_Actions is determined by
2062 -- its Expression.
2070 -- If not overloaded, then we know the type, and all that needs doing
2071 -- is to check that this type is compatible with the context.
2077 -- In the overloaded case, we must select the interpretation that
2078 -- is compatible with the context (i.e. the type passed to Resolve)
2080 else
2081 -- Loop through possible interpretations
2090 -- We are only interested in interpretations that are compatible
2091 -- with the expected type, any other interpretations are ignored.
2096 Write_Eol;
2099 else
2100 -- Skip the current interpretation if it is disabled by an
2101 -- abstract operator. This action is performed only when the
2102 -- type against which we are resolving is the same as the
2103 -- type of the interpretation.
2110 then
2118 -- First matching interpretation
2126 -- Matching interpretation that is not the first, maybe an
2127 -- error, but there are some cases where preference rules are
2128 -- used to choose between the two possibilities. These and
2129 -- some more obscure cases are handled in Disambiguate.
2131 else
2132 -- If the current statement is part of a predefined library
2133 -- unit, then all interpretations which come from user level
2134 -- packages should not be considered. Check previous and
2135 -- current one.
2143 -- Previous interpretation must be discarded
2153 -- Otherwise apply further disambiguation steps
2158 -- Disambiguation has succeeded. Skip the remaining
2159 -- interpretations.
2169 else
2170 -- Before we issue an ambiguity complaint, check for the
2171 -- case of a subprogram call where at least one of the
2172 -- arguments is Any_Type, and if so suppress the message,
2173 -- since it is a cascaded error. This can also happen for
2174 -- a generalized indexing operation.
2179 then
2180 declare
2184 begin
2200 Write_Eol;
2213 then
2218 then
2222 -- Not that special case, so issue message using the flag
2223 -- Ambiguous to control printing of the header message
2224 -- only at the start of an ambiguous set.
2229 then
2230 Error_Msg_N
2233 else
2234 Error_Msg_NE -- CODEFIX
2242 Error_Msg_N
2244 else
2245 Error_Msg_N -- CODEFIX
2251 then
2252 Report_Ambiguous_Argument;
2258 -- By default, the error message refers to the candidate
2259 -- interpretation. But if it is a predefined operator, it
2260 -- is implicitly declared at the declaration of the type
2261 -- of the operand. Recover the sloc of that declaration
2262 -- for the error message.
2268 Standard_Standard
2269 then
2274 then
2282 Standard_Standard
2283 then
2288 then
2292 -- If this is an indirect call, use the subprogram_type
2293 -- in the message, to have a meaningful location. Also
2294 -- indicate if this is an inherited operation, created
2295 -- by a type declaration.
2300 then
2302 Error_Msg_Sloc :=
2304 else
2311 then
2312 -- Special-case the message for universal_fixed
2313 -- operators, which are not declared with the type
2314 -- of the operand, but appear forever in Standard.
2318 then
2319 Error_Msg_N
2322 else
2323 Error_Msg_N
2327 elsif
2329 then
2330 Error_Msg_N
2332 else
2333 Error_Msg_N -- CODEFIX
2340 -- We have a matching interpretation, Expr_Type is the type
2341 -- from this interpretation, and Seen is the entity.
2343 -- For an operator, just set the entity name. The type will be
2344 -- set by the specific operator resolution routine.
2351 N_Character_Literal,
2352 N_Delta_Aggregate,
2353 N_If_Expression)
2354 then
2357 -- AI05-0139-2: Expression is overloaded because type has
2358 -- implicit dereference. If type matches context, no implicit
2359 -- dereference is involved. If the expression is an entity,
2360 -- generate a reference to it, as this is not done for an
2361 -- overloaded construct during analysis.
2377 then
2378 -- If the node is a general indexing, the dereference is
2379 -- is inserted when resolving the rewritten form, else
2380 -- insert it now.
2384 then
2388 -- For an explicit dereference, attribute reference, range,
2389 -- short-circuit form (which is not an operator node), or call
2390 -- with a name that is an explicit dereference, there is
2391 -- nothing to be done at this point.
2394 N_And_Then,
2395 N_Explicit_Dereference,
2396 N_Identifier,
2397 N_Indexed_Component,
2398 N_Or_Else,
2399 N_Range,
2400 N_Selected_Component,
2401 N_Slice)
2403 then
2406 -- For procedure or function calls, set the type of the name,
2407 -- and also the entity pointer for the prefix.
2411 then
2418 then
2423 -- For all other cases, just set the type of the Name
2425 else
2433 -- Move to next interpretation
2441 -- At this stage Found indicates whether or not an acceptable
2442 -- interpretation exists. If not, then we have an error, except that if
2443 -- the context is Any_Type as a result of some other error, then we
2444 -- suppress the error report.
2449 -- If type we are looking for is Void, then this is the procedure
2450 -- call case, and the error is simply that what we gave is not a
2451 -- procedure name (we think of procedure calls as expressions with
2452 -- types internally, but the user doesn't think of them this way).
2456 -- Special case message if function used as a procedure
2461 then
2462 Error_Msg_NE
2465 Error_Msg_N
2469 -- Otherwise give general message (not clear what cases this
2470 -- covers, but no harm in providing for them).
2472 else
2478 -- Otherwise we do have a subexpression with the wrong type
2480 -- Check for the case of an allocator which uses an access type
2481 -- instead of the designated type. This is a common error and we
2482 -- specialize the message, posting an error on the operand of the
2483 -- allocator, complaining that we expected the designated type of
2484 -- the allocator.
2490 then
2494 -- Check for view mismatch on Null in instances, for which the
2495 -- view-swapping mechanism has no identifier.
2501 then
2506 -- Check for an aggregate. Sometimes we can get bogus aggregates
2507 -- from misuse of parentheses, and we are about to complain about
2508 -- the aggregate without even looking inside it.
2510 -- Instead, if we have an aggregate of type Any_Composite, then
2511 -- analyze and resolve the component fields, and then only issue
2512 -- another message if we get no errors doing this (otherwise
2513 -- assume that the errors in the aggregate caused the problem).
2517 then
2518 -- Disable expansion in any case. If there is a type mismatch
2519 -- it may be fatal to try to expand the aggregate. The flag
2520 -- would otherwise be set to false when the error is posted.
2524 declare
2526 -- Check one aggregate, and set Found to True if we have a
2527 -- definite error in any of its elements
2530 -- Check one element of aggregate and set Found to True if
2531 -- we definitely have an error in the element.
2533 ----------------
2534 -- Check_Aggr --
2535 ----------------
2540 begin
2553 -- If this is a default-initialized component, then
2554 -- there is nothing to check. The box will be
2555 -- replaced by the appropriate call during late
2556 -- expansion.
2560 then
2569 ----------------
2570 -- Check_Elmt --
2571 ----------------
2574 begin
2575 -- If we have a nested aggregate, go inside it (to
2576 -- attempt a naked analyze-resolve of the aggregate can
2577 -- cause undesirable cascaded errors). Do not resolve
2578 -- expression if it needs a type from context, as for
2579 -- integer * fixed expression.
2584 else
2589 then
2599 begin
2604 -- Looks like we have a type error, but check for special case
2605 -- of Address wanted, integer found, with the configuration pragma
2606 -- Allow_Integer_Address active. If we have this case, introduce
2607 -- an unchecked conversion to allow the integer expression to be
2608 -- treated as an Address. The reverse case of integer wanted,
2609 -- Address found, is treated in an analogous manner.
2616 -- Under relaxed RM semantics silently replace occurrences of null
2617 -- by System.Address_Null.
2625 -- That special Allow_Integer_Address check did not apply, so we
2626 -- have a real type error. If an error message was issued already,
2627 -- Found got reset to True, so if it's still False, issue standard
2628 -- Wrong_Type message.
2632 declare
2635 begin
2641 -- Protected operation: retrieve operation name
2645 else
2650 Error_Msg_NE
2656 declare
2660 begin
2667 Error_Msg_NE
2673 else
2677 else
2683 Resolution_Failed;
2686 -- Test if we have more than one interpretation for the context
2689 Resolution_Failed;
2692 -- Only one intepretation
2694 else
2695 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2696 -- the "+" on T is abstract, and the operands are of universal type,
2697 -- the above code will have (incorrectly) resolved the "+" to the
2698 -- universal one in Standard. Therefore check for this case and give
2699 -- an error. We can't do this earlier, because it would cause legal
2700 -- cases to get errors (when some other type has an abstract "+").
2706 then
2711 then
2712 Error_Msg_NE
2721 -- Here we have an acceptable interpretation for the context
2723 -- Propagate type information and normalize tree for various
2724 -- predefined operations. If the context only imposes a class of
2725 -- types, rather than a specific type, propagate the actual type
2726 -- downward.
2732 Typ = Any_Discrete
2733 then
2736 -- Any_Fixed is legal in a real context only if a specific fixed-
2737 -- point type is imposed. If Norman Cohen can be confused by this,
2738 -- it deserves a separate message.
2742 then
2749 -- A user-defined operator is transformed into a function call at
2750 -- this point, so that further processing knows that operators are
2751 -- really operators (i.e. are predefined operators). User-defined
2752 -- operators that are intrinsic are just renamings of the predefined
2753 -- ones, and need not be turned into calls either, but if they rename
2754 -- a different operator, we must transform the node accordingly.
2755 -- Instantiations of Unchecked_Conversion are intrinsic but are
2756 -- treated as functions, even if given an operator designator.
2761 then
2766 and then
2768 N_Subprogram_Renaming_Declaration
2769 then
2772 -- If the node is rewritten, it will be fully resolved in
2773 -- Rewrite_Renamed_Operator.
2782 when N_Aggregate =>
2783 Resolve_Aggregate (N, Ctx_Type);
2785 when N_Allocator =>
2786 Resolve_Allocator (N, Ctx_Type);
2788 when N_Short_Circuit =>
2789 Resolve_Short_Circuit (N, Ctx_Type);
2791 when N_Attribute_Reference =>
2792 Resolve_Attribute (N, Ctx_Type);
2794 when N_Case_Expression =>
2795 Resolve_Case_Expression (N, Ctx_Type);
2797 when N_Character_Literal =>
2798 Resolve_Character_Literal (N, Ctx_Type);
2800 when N_Delta_Aggregate =>
2801 Resolve_Delta_Aggregate (N, Ctx_Type);
2803 when N_Expanded_Name =>
2804 Resolve_Entity_Name (N, Ctx_Type);
2806 when N_Explicit_Dereference =>
2807 Resolve_Explicit_Dereference (N, Ctx_Type);
2809 when N_Expression_With_Actions =>
2810 Resolve_Expression_With_Actions (N, Ctx_Type);
2812 when N_Extension_Aggregate =>
2813 Resolve_Extension_Aggregate (N, Ctx_Type);
2815 when N_Function_Call =>
2816 Resolve_Call (N, Ctx_Type);
2818 when N_Identifier =>
2819 Resolve_Entity_Name (N, Ctx_Type);
2821 when N_If_Expression =>
2822 Resolve_If_Expression (N, Ctx_Type);
2824 when N_Indexed_Component =>
2825 Resolve_Indexed_Component (N, Ctx_Type);
2827 when N_Integer_Literal =>
2828 Resolve_Integer_Literal (N, Ctx_Type);
2830 when N_Membership_Test =>
2831 Resolve_Membership_Op (N, Ctx_Type);
2833 when N_Null =>
2834 Resolve_Null (N, Ctx_Type);
2836 when N_Op_And
2837 | N_Op_Or
2838 | N_Op_Xor
2839 =>
2840 Resolve_Logical_Op (N, Ctx_Type);
2842 when N_Op_Eq
2843 | N_Op_Ne
2844 =>
2845 Resolve_Equality_Op (N, Ctx_Type);
2847 when N_Op_Ge
2848 | N_Op_Gt
2849 | N_Op_Le
2850 | N_Op_Lt
2851 =>
2852 Resolve_Comparison_Op (N, Ctx_Type);
2854 when N_Op_Not =>
2855 Resolve_Op_Not (N, Ctx_Type);
2857 when N_Op_Add
2858 | N_Op_Divide
2859 | N_Op_Mod
2860 | N_Op_Multiply
2861 | N_Op_Rem
2862 | N_Op_Subtract
2863 =>
2864 Resolve_Arithmetic_Op (N, Ctx_Type);
2866 when N_Op_Concat =>
2867 Resolve_Op_Concat (N, Ctx_Type);
2869 when N_Op_Expon =>
2870 Resolve_Op_Expon (N, Ctx_Type);
2872 when N_Op_Abs
2873 | N_Op_Minus
2874 | N_Op_Plus
2875 =>
2876 Resolve_Unary_Op (N, Ctx_Type);
2878 when N_Op_Shift =>
2879 Resolve_Shift (N, Ctx_Type);
2881 when N_Procedure_Call_Statement =>
2882 Resolve_Call (N, Ctx_Type);
2884 when N_Operator_Symbol =>
2885 Resolve_Operator_Symbol (N, Ctx_Type);
2887 when N_Qualified_Expression =>
2888 Resolve_Qualified_Expression (N, Ctx_Type);
2890 -- Why is the following null, needs a comment ???
2892 when N_Quantified_Expression =>
2893 null;
2895 when N_Raise_Expression =>
2896 Resolve_Raise_Expression (N, Ctx_Type);
2898 when N_Raise_xxx_Error =>
2899 Set_Etype (N, Ctx_Type);
2901 when N_Range =>
2902 Resolve_Range (N, Ctx_Type);
2904 when N_Real_Literal =>
2905 Resolve_Real_Literal (N, Ctx_Type);
2907 when N_Reduction_Expression =>
2908 null;
2909 -- Resolve (Expression (N), Ctx_Type);
2911 when N_Reduction_Expression_Parameter =>
2912 null;
2914 when N_Reference =>
2915 Resolve_Reference (N, Ctx_Type);
2917 when N_Selected_Component =>
2918 Resolve_Selected_Component (N, Ctx_Type);
2920 when N_Slice =>
2921 Resolve_Slice (N, Ctx_Type);
2923 when N_String_Literal =>
2924 Resolve_String_Literal (N, Ctx_Type);
2926 when N_Target_Name =>
2927 Resolve_Target_Name (N, Ctx_Type);
2929 when N_Type_Conversion =>
2930 Resolve_Type_Conversion (N, Ctx_Type);
2932 when N_Unchecked_Expression =>
2933 Resolve_Unchecked_Expression (N, Ctx_Type);
2935 when N_Unchecked_Type_Conversion =>
2936 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2937 end case;
2939 -- Mark relevant use-type and use-package clauses as effective using
2940 -- the original node because constant folding may have occured and
2941 -- removed references that need to be examined.
2943 if Nkind (Original_Node (N)) in N_Op then
2944 Mark_Use_Clauses (Original_Node (N));
2945 end if;
2947 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2948 -- expression of an anonymous access type that occurs in the context
2949 -- of a named general access type, except when the expression is that
2950 -- of a membership test. This ensures proper legality checking in
2951 -- terms of allowed conversions (expressions that would be illegal to
2952 -- convert implicitly are allowed in membership tests).
2954 if Ada_Version >= Ada_2012
2955 and then Ekind (Ctx_Type) = E_General_Access_Type
2956 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2957 and then Nkind (Parent (N)) not in N_Membership_Test
2958 then
2959 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2960 Analyze_And_Resolve (N, Ctx_Type);
2961 end if;
2963 -- If the subexpression was replaced by a non-subexpression, then
2964 -- all we do is to expand it. The only legitimate case we know of
2965 -- is converting procedure call statement to entry call statements,
2966 -- but there may be others, so we are making this test general.
2968 if Nkind (N) not in N_Subexpr then
2969 Debug_A_Exit ("resolving ", N, " (done)");
2970 Expand (N);
2971 return;
2972 end if;
2974 -- The expression is definitely NOT overloaded at this point, so
2975 -- we reset the Is_Overloaded flag to avoid any confusion when
2976 -- reanalyzing the node.
2978 Set_Is_Overloaded (N, False);
2980 -- Freeze expression type, entity if it is a name, and designated
2981 -- type if it is an allocator (RM 13.14(10,11,13)).
2983 -- Now that the resolution of the type of the node is complete, and
2984 -- we did not detect an error, we can expand this node. We skip the
2985 -- expand call if we are in a default expression, see section
2986 -- "Handling of Default Expressions" in Sem spec.
2988 Debug_A_Exit ("resolving ", N, " (done)");
2990 -- We unconditionally freeze the expression, even if we are in
2991 -- default expression mode (the Freeze_Expression routine tests this
2992 -- flag and only freezes static types if it is set).
2994 -- Ada 2012 (AI05-177): The declaration of an expression function
2995 -- does not cause freezing, but we never reach here in that case.
2996 -- Here we are resolving the corresponding expanded body, so we do
2997 -- need to perform normal freezing.
2999 -- As elsewhere we do not emit freeze node within a generic. We make
3000 -- an exception for entities that are expressions, only to detect
3001 -- misuses of deferred constants and preserve the output of various
3002 -- tests.
3004 if not Inside_A_Generic or else Is_Entity_Name (N) then
3005 Freeze_Expression (N);
3006 end if;
3008 -- Now we can do the expansion
3010 Expand (N);
3011 end if;
3012 end Resolve;
3014 -------------
3015 -- Resolve --
3016 -------------
3018 -- Version with check(s) suppressed
3020 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3021 begin
3022 if Suppress = All_Checks then
3023 declare
3024 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3025 begin
3026 Scope_Suppress.Suppress := (others => True);
3027 Resolve (N, Typ);
3028 Scope_Suppress.Suppress := Sva;
3029 end;
3031 else
3032 declare
3033 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3034 begin
3035 Scope_Suppress.Suppress (Suppress) := True;
3036 Resolve (N, Typ);
3037 Scope_Suppress.Suppress (Suppress) := Svg;
3038 end;
3039 end if;
3040 end Resolve;
3042 -------------
3043 -- Resolve --
3044 -------------
3046 -- Version with implicit type
3048 procedure Resolve (N : Node_Id) is
3049 begin
3050 Resolve (N, Etype (N));
3051 end Resolve;
3053 ---------------------
3054 -- Resolve_Actuals --
3055 ---------------------
3057 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3058 Loc : constant Source_Ptr := Sloc (N);
3059 A : Node_Id;
3060 A_Id : Entity_Id;
3061 A_Typ : Entity_Id := Empty; -- init to avoid warning
3062 F : Entity_Id;
3063 F_Typ : Entity_Id;
3064 Prev : Node_Id := Empty;
3065 Orig_A : Node_Id;
3066 Real_F : Entity_Id := Empty; -- init to avoid warning
3068 Real_Subp : Entity_Id;
3069 -- If the subprogram being called is an inherited operation for
3070 -- a formal derived type in an instance, Real_Subp is the subprogram
3071 -- that will be called. It may have different formal names than the
3072 -- operation of the formal in the generic, so after actual is resolved
3073 -- the name of the actual in a named association must carry the name
3074 -- of the actual of the subprogram being called.
3076 procedure Check_Aliased_Parameter;
3077 -- Check rules on aliased parameters and related accessibility rules
3078 -- in (RM 3.10.2 (10.2-10.4)).
3080 procedure Check_Argument_Order;
3081 -- Performs a check for the case where the actuals are all simple
3082 -- identifiers that correspond to the formal names, but in the wrong
3083 -- order, which is considered suspicious and cause for a warning.
3085 procedure Check_Prefixed_Call;
3086 -- If the original node is an overloaded call in prefix notation,
3088 -- Try_Object_Operation has already verified that there is a valid
3089 -- interpretation, but the form of the actual can only be determined
3090 -- once the primitive operation is identified.
3093 -- Emit an error concerning the illegal usage of an effectively volatile
3094 -- object in interfering context (SPARK RM 7.13(12)).
3097 -- If the actual is missing in a call, insert in the actuals list
3098 -- an instance of the default expression. The insertion is always
3099 -- a named association.
3102 -- Check whether T1 and T2, or their full views, are derived from a
3103 -- common type. Used to enforce the restrictions on array conversions
3104 -- of AI95-00246.
3107 -- Predicate to determine whether an actual that is a concatenation
3108 -- will be evaluated statically and does not need a transient scope.
3109 -- This must be determined before the actual is resolved and expanded
3110 -- because if needed the transient scope must be introduced earlier.
3112 -----------------------------
3113 -- Check_Aliased_Parameter --
3114 -----------------------------
3119 begin
3127 else
3134 -- In a generic body assume the worst for generic formals:
3135 -- they can have a constrained partial view (AI05-041).
3141 then
3144 else
3149 else
3161 then
3169 then
3170 Error_Msg_N
3176 --------------------------
3177 -- Check_Argument_Order --
3178 --------------------------
3181 begin
3182 -- Nothing to do if no parameters, or original node is neither a
3183 -- function call nor a procedure call statement (happens in the
3184 -- operator-transformed-to-function call case), or the call does
3185 -- not come from source, or this warning is off.
3187 if not Warn_On_Parameter_Order
3191 then
3195 declare
3198 begin
3199 -- Nothing to do if only one parameter
3205 -- Here if at least two arguments
3207 declare
3213 -- Set True if an out of order case is found
3215 begin
3216 -- Collect identifier names of actuals, fail if any actual is
3217 -- not a simple identifier, and record max length of name.
3223 else
3229 -- If we got this far, all actuals are identifiers and the list
3230 -- of their names is stored in the Actuals array.
3235 -- If we ran out of formals, that's odd, probably an error
3236 -- which will be detected elsewhere, but abandon the search.
3242 -- If name matches and is in order OK
3247 else
3248 -- If no match, see if it is elsewhere in list and if so
3249 -- flag potential wrong order if type is compatible.
3253 and then
3255 then
3261 -- No match
3269 -- If Formals left over, also probably an error, skip warning
3275 -- Here we give the warning if something was out of order
3278 Error_Msg_N
3285 -------------------------
3286 -- Check_Prefixed_Call --
3287 -------------------------
3296 begin
3297 -- Check whether the call is a prefixed call, with or without
3298 -- additional actuals.
3301 or else
3307 then
3310 then
3311 -- Introduce dereference on object in prefix
3313 New_A :=
3321 then
3322 -- Introduce an implicit 'Access in prefix
3325 Error_Msg_NE
3341 ---------------------------------------
3342 -- Flag_Effectively_Volatile_Objects --
3343 ---------------------------------------
3347 -- Determine whether arbitrary node N denotes an effectively volatile
3348 -- object and if it does, emit an error.
3350 -----------------
3351 -- Flag_Object --
3352 -----------------
3357 begin
3358 -- Do not consider nested function calls because they have already
3359 -- been processed during their own resolution.
3371 then
3372 Error_Msg_N
3384 -- Start of processing for Flag_Effectively_Volatile_Objects
3386 begin
3390 --------------------
3391 -- Insert_Default --
3392 --------------------
3398 begin
3399 -- Missing argument in call, nothing to insert
3404 else
3405 -- Note that we do a full New_Copy_Tree, so that any associated
3406 -- Itypes are properly copied. This may not be needed any more,
3407 -- but it does no harm as a safety measure. Defaults of a generic
3408 -- formal may be out of bounds of the corresponding actual (see
3409 -- cc1311b) and an additional check may be required.
3411 Actval :=
3412 New_Copy_Tree
3417 -- Propagate dimension information, if any.
3423 then
3429 then
3432 then
3433 -- If default is a real literal, do not introduce a
3434 -- conversion whose effect may depend on the run-time
3435 -- size of universal real.
3439 else
3450 -- Resolve aggregates with their base type, to avoid scope
3451 -- anomalies: the subtype was first built in the subprogram
3452 -- declaration, and the current call may be nested.
3456 else
3460 else
3463 -- See note above concerning aggregates
3467 then
3470 -- Resolve entities with their own type, which may differ from
3471 -- the type of a reference in a generic context (the view
3472 -- swapping mechanism did not anticipate the re-analysis of
3473 -- default values in calls).
3478 else
3483 -- If default is a tag indeterminate function call, propagate tag
3484 -- to obtain proper dispatching.
3488 then
3493 -- If the default expression raises constraint error, then just
3494 -- silently replace it with an N_Raise_Constraint_Error node, since
3495 -- we already gave the warning on the subprogram spec. If node is
3496 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3497 -- the warnings removal machinery.
3501 then
3510 Assoc :=
3515 -- Case of insertion is first named actual
3519 then
3526 else
3530 else
3534 -- Case of insertion is not first named actual
3536 else
3537 Set_Next_Named_Actual
3549 -------------------
3550 -- Same_Ancestor --
3551 -------------------
3557 begin
3560 then
3566 then
3573 --------------------------
3574 -- Static_Concatenation --
3575 --------------------------
3578 begin
3585 -- Concatenation is static when both operands are static and
3586 -- the concatenation operator is a predefined one.
3589 and then
3591 and then
3596 declare
3598 begin
3601 and then
3605 else
3611 -- Start of processing for Resolve_Actuals
3613 begin
3614 Check_Argument_Order;
3618 and then In_Instance
3621 then
3623 else
3628 Check_Prefixed_Call;
3642 -- If we have an error in any actual or formal, indicated by a type
3643 -- of Any_Type, then abandon resolution attempt, and set result type
3644 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3645 -- type is imposed from context.
3649 then
3656 -- Case where actual is present
3658 -- If the actual is an entity, generate a reference to it now. We
3659 -- do this before the actual is resolved, because a formal of some
3660 -- protected subprogram, or a task discriminant, will be rewritten
3661 -- during expansion, and the source entity reference may be lost.
3666 then
3667 -- Annotate the tree by creating a variable reference marker when
3668 -- the actual denotes a variable reference, in case the reference
3669 -- is folded or optimized away. The variable reference marker is
3670 -- automatically saved for later examination by the ABE Processing
3671 -- phase. The status of the reference is set as follows:
3673 -- status mode
3674 -- read IN, IN OUT
3675 -- write IN OUT, OUT
3677 Build_Variable_Reference_Marker
3687 then
3694 -- RM 6.4.1(12): For an out parameter that is passed by
3695 -- copy, the formal parameter object is created, and:
3697 -- * For an access type, the formal parameter is initialized
3698 -- from the value of the actual, without checking that the
3699 -- value satisfies any constraint, any predicate, or any
3700 -- exclusion of the null value.
3702 -- * For a scalar type that has the Default_Value aspect
3703 -- specified, the formal parameter is initialized from the
3704 -- value of the actual, without checking that the value
3705 -- satisfies any constraint or any predicate.
3706 -- I do not understand why this case is included??? this is
3707 -- not a case where an OUT parameter is treated as IN OUT.
3709 -- * For a composite type with discriminants or that has
3710 -- implicit initial values for any subcomponents, the
3711 -- behavior is as for an in out parameter passed by copy.
3713 -- Hence for these cases we generate the read reference now
3714 -- (the write reference will be generated later by
3715 -- Note_Possible_Modification).
3718 and then
3720 or else
3722 and then
3724 or else
3727 or else Is_Partially_Initialized_Type
3729 then
3739 then
3740 -- If style checking mode on, check match of formal name
3748 -- If the formal is Out or In_Out, do not resolve and expand the
3749 -- conversion, because it is subsequently expanded into explicit
3750 -- temporaries and assignments. However, the object of the
3751 -- conversion can be resolved. An exception is the case of tagged
3752 -- type conversion with a class-wide actual. In that case we want
3753 -- the tag check to occur and no temporary will be needed (no
3754 -- representation change can occur) and the parameter is passed by
3755 -- reference, so we go ahead and resolve the type conversion.
3756 -- Another exception is the case of reference to component or
3757 -- subcomponent of a bit-packed array, in which case we want to
3758 -- defer expansion to the point the in and out assignments are
3759 -- performed.
3764 then
3767 then
3768 -- In a view conversion, the conversion must be legal in
3769 -- both directions, and thus both component types must be
3770 -- aliased, or neither (4.6 (8)).
3772 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3773 -- the privacy requirement should not apply to generic
3774 -- types, and should be checked in an instance. ARG query
3775 -- is in order ???
3779 then
3780 Error_Msg_N
3784 -- Comment here??? what set of cases???
3786 elsif
3788 then
3789 -- Check view conv between unrelated by ref array types
3793 then
3794 Error_Msg_N
3798 -- In Ada 2005 mode, check view conversion component
3799 -- type cannot be private, tagged, or volatile. Note
3800 -- that we only apply this to source conversions. The
3801 -- generated code can contain conversions which are
3802 -- not subject to this test, and we cannot extract the
3803 -- component type in such cases since it is not present.
3807 then
3808 declare
3810 Component_Type
3812 begin
3817 then
3818 Error_Msg_N
3829 -- Resolve expression if conversion is all OK
3834 then
3838 -- If the actual is a function call that returns a limited
3839 -- unconstrained object that needs finalization, create a
3840 -- transient scope for it, so that it can receive the proper
3841 -- finalization list.
3843 elsif Expander_Active
3849 then
3853 -- A small optimization: if one of the actuals is a concatenation
3854 -- create a block around a procedure call to recover stack space.
3855 -- This alleviates stack usage when several procedure calls in
3856 -- the same statement list use concatenation. We do not perform
3857 -- this wrapping for code statements, where the argument is a
3858 -- static string, and we want to preserve warnings involving
3859 -- sequences of such statements.
3861 elsif Expander_Active
3867 then
3871 else
3875 and then
3878 then
3879 Error_Msg_N
3892 -- (Ada 2005: AI-251): If the actual is an allocator whose
3893 -- directly designated type is a class-wide interface, we build
3894 -- an anonymous access type to use it as the type of the
3895 -- allocator. Later, when the subprogram call is expanded, if
3896 -- the interface has a secondary dispatch table the expander
3897 -- will add a type conversion to force the correct displacement
3898 -- of the pointer.
3901 declare
3907 begin
3910 then
3913 Set_Directly_Designated_Type
3918 -- Ada 2005, AI-162:If the actual is an allocator, the
3919 -- innermost enclosing statement is the master of the
3920 -- created object. This needs to be done with expansion
3921 -- enabled only, otherwise the transient scope will not
3922 -- be removed in the expansion of the wrapped construct.
3924 if Expander_Active
3927 then
3928 Establish_Transient_Scope
3938 -- (Ada 2005): The call may be to a primitive operation of a
3939 -- tagged synchronized type, declared outside of the type. In
3940 -- this case the controlling actual must be converted to its
3941 -- corresponding record type, which is the formal type. The
3942 -- actual may be a subtype, either because of a constraint or
3943 -- because it is a generic actual, so use base type to locate
3944 -- concurrent type.
3951 then
3952 -- If the actual is overloaded, look for an interpretation
3953 -- that has a synchronized type.
3958 else
3959 declare
3963 begin
3968 then
3978 declare
3981 begin
3984 else
3988 -- Tagged synchronized type (case 1): the actual is a
3989 -- concurrent type.
3993 then
3995 Unchecked_Convert_To
3999 -- Tagged synchronized type (case 2): the formal is a
4000 -- concurrent type.
4003 and then Present
4008 then
4011 -- Common case
4013 else
4018 -- Not a synchronized operation
4020 else
4028 -- An actual cannot be an untagged formal incomplete type
4033 then
4034 Error_Msg_N
4040 N_Procedure_Call_Statement)
4041 then
4042 -- In formal mode, check that actual parameters matching
4043 -- formals of tagged types are objects (or ancestor type
4044 -- conversions of objects), not general expressions.
4051 declare
4056 begin
4058 Check_SPARK_05_Restriction
4061 -- In formal mode, the only view conversions are those
4062 -- involving ancestor conversion of an extended type.
4064 elsif not
4070 then
4071 if Ekind_In
4073 then
4074 Check_SPARK_05_Restriction
4077 else
4078 Check_SPARK_05_Restriction
4082 else
4087 else
4091 -- In formal mode, the only view conversions are those
4092 -- involving ancestor conversion of an extended type.
4096 then
4097 Check_SPARK_05_Restriction
4103 -- has warnings suppressed, then we reset Never_Set_In_Source for
4104 -- the calling entity. The reason for this is to catch cases like
4105 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4106 -- uses trickery to modify an IN parameter.
4113 then
4117 -- Perform error checks for IN and IN OUT parameters
4121 -- Check unset reference. For scalar parameters, it is clearly
4122 -- wrong to pass an uninitialized value as either an IN or
4123 -- IN-OUT parameter. For composites, it is also clearly an
4124 -- error to pass a completely uninitialized value as an IN
4125 -- parameter, but the case of IN OUT is trickier. We prefer
4126 -- not to give a warning here. For example, suppose there is
4127 -- a routine that sets some component of a record to False.
4128 -- It is perfectly reasonable to make this IN-OUT and allow
4129 -- either initialized or uninitialized records to be passed
4130 -- in this case.
4132 -- For partially initialized composite values, we also avoid
4133 -- warnings, since it is quite likely that we are passing a
4134 -- partially initialized value and only the initialized fields
4135 -- will in fact be read in the subprogram.
4140 then
4144 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4145 -- actual to a nested call, since this constitutes a reading of
4146 -- the parameter, which is not allowed.
4151 then
4156 -- In -gnatd.q mode, forget that a given array is constant when
4157 -- it is passed as an IN parameter to a foreign-convention
4158 -- subprogram. This is in case the subprogram evilly modifies the
4159 -- object. Of course, correct code would use IN OUT.
4161 if Debug_Flag_Dot_Q
4167 then
4171 -- Case of OUT or IN OUT parameter
4175 -- For an Out parameter, check for useless assignment. Note
4176 -- that we can't set Last_Assignment this early, because we may
4177 -- kill current values in Resolve_Call, and that call would
4178 -- clobber the Last_Assignment field.
4180 -- Note: call Warn_On_Useless_Assignment before doing the check
4181 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4182 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4183 -- reflects the last assignment, not this one.
4190 then
4195 -- Validate the form of the actual. Note that the call to
4196 -- Is_OK_Variable_For_Out_Formal generates the required
4197 -- reference in this case.
4199 -- A call to an initialization procedure for an aggregate
4200 -- component may initialize a nested component of a constant
4201 -- designated object. In this context the object is variable.
4205 then
4211 then
4212 Error_Msg_N
4217 Error_Msg_N
4224 -- What's the following about???
4228 else
4229 Kill_All_Checks;
4238 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4242 -- Apply predicate tests except in certain special cases. Note
4243 -- that it might be more consistent to apply these only when
4244 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4245 -- for the outbound predicate tests ??? In any case indicate
4246 -- the function being called, for better warnings if the call
4247 -- leads to an infinite recursion.
4253 -- Apply required constraint checks
4255 -- Gigi looks at the check flag and uses the appropriate types.
4256 -- For now since one flag is used there is an optimization
4257 -- which might not be done in the IN OUT case since Gigi does
4258 -- not do any analysis. More thought required about this ???
4260 -- In fact is this comment obsolete??? doesn't the expander now
4261 -- generate all these tests anyway???
4274 then
4277 -- For view conversions of a discriminated object, apply
4278 -- check to object itself, the conversion alreay has the
4279 -- proper type.
4283 then
4290 then
4296 then
4299 else
4303 -- Ada 2005 (AI-231): Note that the controlling parameter case
4304 -- already existed in Ada 95, which is partially checked
4305 -- elsewhere (see Checks), and we don't want the warning
4306 -- message to differ.
4311 then
4313 Apply_Compile_Time_Constraint_Error
4319 Apply_Compile_Time_Constraint_Error
4328 -- Checks for OUT parameters and IN OUT parameters
4332 -- If there is a type conversion, make sure the return value
4333 -- meets the constraints of the variable before the conversion.
4337 Apply_Scalar_Range_Check
4340 -- In addition, the returned value of the parameter must
4341 -- satisfy the bounds of the object type (see comment
4342 -- below).
4346 else
4347 Apply_Range_Check
4351 -- If no conversion, apply scalar range checks and length check
4352 -- based on the subtype of the actual (NOT that of the formal).
4353 -- This indicates that the check takes place on return from the
4354 -- call. During expansion the required constraint checks are
4355 -- inserted. In GNATprove mode, in the absence of expansion,
4356 -- the flag indicates that the returned value is valid.
4358 else
4364 then
4366 else
4371 -- Note: we do not apply the predicate checks for the case of
4372 -- OUT and IN OUT parameters. They are instead applied in the
4373 -- Expand_Actuals routine in Exp_Ch6.
4376 -- An actual associated with an access parameter is implicitly
4377 -- converted to the anonymous access type of the formal and must
4378 -- satisfy the legality checks for access conversions.
4382 Error_Msg_N
4386 -- If the actual is an access selected component of a variable,
4387 -- the call may modify its designated object. It is reasonable
4388 -- to treat this as a potential modification of the enclosing
4389 -- record, to prevent spurious warnings that it should be
4390 -- declared as a constant, because intuitively programmers
4391 -- regard the designated subcomponent as part of the record.
4396 then
4401 -- Check bad case of atomic/volatile argument (RM C.6(12))
4405 then
4408 then
4409 Error_Msg_NE
4415 then
4416 Error_Msg_NE
4422 -- Check that subprograms don't have improper controlling
4423 -- arguments (RM 3.9.2 (9)).
4425 -- A primitive operation may have an access parameter of an
4426 -- incomplete tagged type, but a dispatching call is illegal
4427 -- if the type is still incomplete.
4433 declare
4435 begin
4439 then
4440 Error_Msg_NE
4451 -- Apply legality rule 3.9.2 (9/1)
4456 and then not In_Instance
4457 then
4462 Error_Msg_NE
4466 -- Apply the checks described in 3.10.2(27): if the context is a
4467 -- specific access-to-object, the actual cannot be class-wide.
4468 -- Use base type to exclude access_to_subprogram cases.
4475 and then
4480 -- Disable these checks for call to imported C++ subprograms
4482 and then not
4486 then
4487 Error_Msg_N
4492 Error_Msg_NE
4497 Check_Aliased_Parameter;
4501 -- If it is a named association, treat the selector_name as a
4502 -- proper identifier, and mark the corresponding entity.
4506 -- Ignore reference in SPARK mode, as it refers to an entity not
4507 -- in scope at the point of reference, so the reference should
4508 -- be ignored for computing effects of subprograms.
4510 and then not GNATprove_Mode
4511 then
4512 -- If subprogram is overridden, use name of formal that
4513 -- is being called.
4519 else
4533 -- The following checks are only relevant when SPARK_Mode is on as
4534 -- they are not standard Ada legality rule. Internally generated
4535 -- temporaries are ignored.
4539 -- An effectively volatile object may act as an actual when the
4540 -- corresponding formal is of a non-scalar effectively volatile
4541 -- type (SPARK RM 7.1.3(11)).
4545 then
4548 -- An effectively volatile object may act as an actual in a
4549 -- call to an instance of Unchecked_Conversion.
4550 -- (SPARK RM 7.1.3(11)).
4555 -- The actual denotes an object
4558 Error_Msg_N
4562 -- Otherwise the actual denotes an expression. Inspect the
4563 -- expression and flag each effectively volatile object with
4564 -- enabled property Async_Writers or Effective_Reads as illegal
4565 -- because it apprears within an interfering context. Note that
4566 -- this is usually done in Resolve_Entity_Name, but when the
4567 -- effectively volatile object appears as an actual in a call,
4568 -- the call must be resolved first.
4570 else
4574 -- An effectively volatile variable cannot act as an actual
4575 -- parameter in a procedure call when the variable has enabled
4576 -- property Effective_Reads and the corresponding formal is of
4577 -- mode IN (SPARK RM 7.1.3(10)).
4582 then
4588 then
4589 Error_Msg_NE
4600 -- A formal parameter of a specific tagged type whose related
4601 -- subprogram is subject to pragma Extensions_Visible with value
4602 -- "False" cannot act as an actual in a subprogram with value
4603 -- "True" (SPARK RM 6.1.7(3)).
4607 Extensions_Visible_True
4608 then
4609 Error_Msg_N
4612 Error_Msg_NE
4616 -- The actual parameter of a Ghost subprogram whose formal is of
4617 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4625 then
4626 Error_Msg_NE
4632 else
4639 -- Case where actual is not present
4641 else
4642 Insert_Default;
4653 -----------------------
4654 -- Resolve_Allocator --
4655 -----------------------
4667 procedure Check_Allocator_Discrim_Accessibility
4670 -- Check that accessibility level associated with an access discriminant
4671 -- initialized in an allocator by the expression Disc_Exp is not deeper
4672 -- than the level of the allocator type Alloc_Typ. An error message is
4673 -- issued if this condition is violated. Specialized checks are done for
4674 -- the cases of a constraint expression which is an access attribute or
4675 -- an access discriminant.
4678 -- If the allocator is an actual in a call, it is allowed to be class-
4679 -- wide when the context is not because it is a controlling actual.
4681 -------------------------------------------
4682 -- Check_Allocator_Discrim_Accessibility --
4683 -------------------------------------------
4685 procedure Check_Allocator_Discrim_Accessibility
4688 is
4689 begin
4692 then
4693 Error_Msg_N
4696 -- When the expression is an Access attribute the level of the prefix
4697 -- object must not be deeper than that of the allocator's type.
4701 Attribute_Access
4704 then
4705 Error_Msg_N
4707 Disc_Exp);
4709 -- When the expression is an access discriminant the check is against
4710 -- the level of the prefix object.
4716 then
4717 Error_Msg_N
4719 Disc_Exp);
4721 -- All other cases are legal
4723 else
4728 ----------------------------
4729 -- In_Dispatching_Context --
4730 ----------------------------
4735 begin
4741 -- Start of processing for Resolve_Allocator
4743 begin
4744 -- Replace general access with specific type
4754 -- For qualified expression, resolve the expression using the given
4755 -- subtype (nothing to do for type mark, subtype indication)
4760 and then not In_Dispatching_Context
4761 then
4762 Error_Msg_N
4770 -- Allocators generated by the build-in-place expansion mechanism
4771 -- are explicitly marked as coming from source but do not need to be
4772 -- checked for limited initialization. To exclude this case, ensure
4773 -- that the parent of the allocator is a source node.
4774 -- The return statement constructed for an Expression_Function does
4775 -- not come from source but requires a limited check.
4779 and then
4781 or else
4785 and then not In_Instance_Body
4786 then
4789 Error_Msg_N
4792 else
4793 Error_Msg_N
4801 -- A qualified expression requires an exact match of the type. Class-
4802 -- wide matching is not allowed.
4807 then
4811 -- Calls to build-in-place functions are not currently supported in
4812 -- allocators for access types associated with a simple storage pool.
4813 -- Supporting such allocators may require passing additional implicit
4814 -- parameters to build-in-place functions (or a significant revision
4815 -- of the current b-i-p implementation to unify the handling for
4816 -- multiple kinds of storage pools). ???
4820 then
4821 declare
4824 begin
4826 and then
4827 Present (Get_Rep_Pragma
4829 then
4830 Error_Msg_N
4837 -- A special accessibility check is needed for allocators that
4838 -- constrain access discriminants. The level of the type of the
4839 -- expression used to constrain an access discriminant cannot be
4840 -- deeper than the type of the allocator (in contrast to access
4841 -- parameters, where the level of the actual can be arbitrary).
4843 -- We can't use Valid_Conversion to perform this check because in
4844 -- general the type of the allocator is unrelated to the type of
4845 -- the access discriminant.
4849 then
4856 then
4859 -- Get the first component expression of the aggregate
4869 else
4873 else
4892 else
4897 else
4906 -- For a subtype mark or subtype indication, freeze the subtype
4908 else
4912 Error_Msg_N
4916 -- A special accessibility check is needed for allocators that
4917 -- constrain access discriminants. The level of the type of the
4918 -- expression used to constrain an access discriminant cannot be
4919 -- deeper than the type of the allocator (in contrast to access
4920 -- parameters, where the level of the actual can be arbitrary).
4921 -- We can't use Valid_Conversion to perform this check because
4922 -- in general the type of the allocator is unrelated to the type
4923 -- of the access discriminant.
4928 then
4938 else
4952 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4953 -- check that the level of the type of the created object is not deeper
4954 -- than the level of the allocator's access type, since extensions can
4955 -- now occur at deeper levels than their ancestor types. This is a
4956 -- static accessibility level check; a run-time check is also needed in
4957 -- the case of an initialized allocator with a class-wide argument (see
4958 -- Expand_Allocator_Expression).
4962 then
4963 declare
4966 begin
4971 else
4977 then
4980 Error_Msg_N
4989 -- Do not apply Ada 2005 accessibility checks on a class-wide
4990 -- allocator if the type given in the allocator is a formal
4991 -- type. A run-time check will be performed in the instance.
5001 -- Check for allocation from an empty storage pool
5006 -- If the context is an unchecked conversion, as may happen within an
5007 -- inlined subprogram, the allocator is being resolved with its own
5008 -- anonymous type. In that case, if the target type has a specific
5009 -- storage pool, it must be inherited explicitly by the allocator type.
5013 then
5014 Set_Associated_Storage_Pool
5022 -- Check that an allocator with task parts isn't for a nested access
5023 -- type when restriction No_Task_Hierarchy applies.
5027 then
5031 -- An illegal allocator may be rewritten as a raise Program_Error
5032 -- statement.
5036 -- Avoid coextension processing for an allocator that is the
5037 -- expansion of a build-in-place function call.
5041 N_Qualified_Expression
5043 N_Function_Call
5044 and then Is_Expanded_Build_In_Place_Call
5046 then
5049 else
5050 -- An anonymous access discriminant is the definition of a
5051 -- coextension.
5055 N_Discriminant_Specification
5056 then
5057 declare
5061 begin
5064 -- Ada 2012 AI05-0052: If the designated type of the
5065 -- allocator is limited, then the allocator shall not
5066 -- be used to define the value of an access discriminant
5067 -- unless the discriminated type is immutably limited.
5072 then
5073 Error_Msg_N
5076 N);
5080 -- Avoid marking an allocator as a dynamic coextension if it is
5081 -- within a static construct.
5086 -- Finalization and deallocation of coextensions utilizes an
5087 -- approximate implementation which does not directly adhere
5088 -- to the semantic rules. Warn on potential issues involving
5089 -- coextensions.
5092 Error_Msg_N
5095 else
5096 Error_Msg_N
5102 -- Cleanup for potential static coextensions
5104 else
5108 -- Anonymous access-to-controlled objects are not finalized on
5109 -- time because this involves run-time ownership and currently
5110 -- this property is not available. In rare cases the object may
5111 -- not be finalized at all. Warn on potential issues involving
5112 -- anonymous access-to-controlled objects.
5116 then
5117 Error_Msg_N
5127 -- Report a simple error: if the designated object is a local task,
5128 -- its body has not been seen yet, and its activation will fail an
5129 -- elaboration check.
5136 then
5142 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5143 -- type with a task component on a subpool. This action must raise
5144 -- Program_Error at runtime.
5150 then
5162 ---------------------------
5163 -- Resolve_Arithmetic_Op --
5164 ---------------------------
5166 -- Used for resolving all arithmetic operators except exponentiation
5177 -- We do the resolution using the base type, because intermediate values
5178 -- in expressions always are of the base type, not a subtype of it.
5181 -- Returns True if N is in a context that expects "any real type"
5184 -- Return True iff given type is Integer or universal real/integer
5187 -- Choose type of integer literal in fixed-point operation to conform
5188 -- to available fixed-point type. T is the type of the other operand,
5189 -- which is needed to determine the expected type of N.
5192 -- Set operand type to T if universal
5194 -------------------------------
5195 -- Expected_Type_Is_Any_Real --
5196 -------------------------------
5199 begin
5200 -- N is the expression after "delta" in a fixed_point_definition;
5201 -- see RM-3.5.9(6):
5204 N_Decimal_Fixed_Point_Definition,
5206 -- N is one of the bounds in a real_range_specification;
5207 -- see RM-3.5.7(5):
5209 N_Real_Range_Specification,
5211 -- N is the expression of a delta_constraint;
5212 -- see RM-J.3(3):
5214 N_Delta_Constraint);
5217 -----------------------------
5218 -- Is_Integer_Or_Universal --
5219 -----------------------------
5226 begin
5232 else
5238 then
5249 ----------------------------
5250 -- Set_Mixed_Mode_Operand --
5251 ----------------------------
5257 begin
5260 -- A universal integer literal is resolved as standard integer
5261 -- except in the case of a fixed-point result, where we leave it
5262 -- as universal (to be handled by Exp_Fixd later on)
5266 else
5274 then
5275 -- A universal real can appear in a fixed-type context. We resolve
5276 -- the literal with that context, even though this might raise an
5277 -- exception prematurely (the other operand may be zero).
5284 then
5285 -- Integer arg in mixed-mode operation. Resolve with universal
5286 -- type, in case preference rule must be applied.
5292 then
5293 -- Not a mixed-mode operation, resolve with context
5299 -- N may itself be a mixed-mode operation, so use context type
5306 then
5307 -- Must be (fixed * fixed) operation, operand must have one
5308 -- compatible interpretation.
5315 then
5316 -- C * F(X) in a fixed context, where C is a real literal or a
5317 -- fixed-point expression. F must have either a fixed type
5318 -- interpretation or an integer interpretation, but not both.
5325 else
5332 else
5340 -- Reanalyze the literal with the fixed type of the context. If
5341 -- context is Universal_Fixed, we are within a conversion, leave
5342 -- the literal as a universal real because there is no usable
5343 -- fixed type, and the target of the conversion plays no role in
5344 -- the resolution.
5346 declare
5350 begin
5353 else
5359 then
5361 else
5369 -- A universal real conditional expression can appear in a fixed-type
5370 -- context and must be resolved with that context to facilitate the
5371 -- code generation to the backend.
5376 then
5379 else
5384 ----------------------
5385 -- Set_Operand_Type --
5386 ----------------------
5389 begin
5392 then
5397 -- Start of processing for Resolve_Arithmetic_Op
5399 begin
5404 then
5408 -- Special-case for mixed-mode universal expressions or fixed point type
5409 -- operation: each argument is resolved separately. The same treatment
5410 -- is required if one of the operands of a fixed point operation is
5411 -- universal real, since in this case we don't do a conversion to a
5412 -- specific fixed-point type (instead the expander handles the case).
5414 -- Set the type of the node to its universal interpretation because
5415 -- legality checks on an exponentiation operand need the context.
5420 then
5431 or else
5434 then
5439 -- If context is a fixed type and one operand is integer, the other
5440 -- is resolved with the type of the context.
5445 then
5452 then
5456 -- If both operands are universal and the context is a floating
5457 -- point type, the operands are resolved to the type of the context.
5463 else
5468 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5469 -- multiplying operators from being used when the expected type is
5470 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5471 -- some cases where the expected type is actually Any_Real;
5472 -- Expected_Type_Is_Any_Real takes care of that case.
5476 then
5480 N_Unchecked_Type_Conversion)
5481 then
5488 else
5491 and then not
5493 N_Unchecked_Type_Conversion)
5494 then
5495 Error_Msg_N
5500 -- The expected type is "any real type" in contexts like
5502 -- type T is delta <universal_fixed-expression> ...
5504 -- in which case we need to set the type to Universal_Real
5505 -- so that static expression evaluation will work properly.
5509 else
5519 then
5524 -- If no previous errors, this is only possible if one operand is
5525 -- overloaded and the context is universal. Resolve as such.
5530 else
5532 and then
5534 then
5538 -- If the context is Universal_Fixed and the operands are also
5539 -- universal fixed, this is an error, unless there is only one
5540 -- applicable fixed_point type (usually Duration).
5548 else
5553 else
5558 -- If one of the arguments was resolved to a non-universal type.
5559 -- label the result of the operation itself with the same type.
5560 -- Do the same for the universal argument, if any.
5572 -- In SPARK, a multiplication or division with operands of fixed point
5573 -- types must be qualified or explicitly converted to identify the
5574 -- result type.
5579 and then
5581 then
5582 Check_SPARK_05_Restriction
5586 -- Set overflow and division checking bit
5593 -- Give warning if explicit division by zero
5597 then
5603 or else
5606 then
5607 -- Specialize the warning message according to the operation.
5608 -- When SPARK_Mode is On, force a warning instead of an error
5609 -- in that case, as this likely corresponds to deactivated
5610 -- code. The following warnings are for the case
5615 -- For division, we have two cases, for float division
5616 -- of an unconstrained float type, on a machine where
5617 -- Machine_Overflows is false, we don't get an exception
5618 -- at run-time, but rather an infinity or Nan. The Nan
5619 -- case is pretty obscure, so just warn about infinities.
5623 and then not Machine_Overflows_On_Target
5624 then
5625 Error_Msg_N
5629 -- For all other cases, we get a Constraint_Error
5631 else
5632 Apply_Compile_Time_Constraint_Error
5639 Apply_Compile_Time_Constraint_Error
5645 Apply_Compile_Time_Constraint_Error
5650 -- Division by zero can only happen with division, rem,
5651 -- and mod operations.
5657 -- In GNATprove mode, we enable the division check so that
5658 -- GNATprove will issue a message if it cannot be proved.
5664 -- Otherwise just set the flag to check at run time
5666 else
5671 -- If Restriction No_Implicit_Conditionals is active, then it is
5672 -- violated if either operand can be negative for mod, or for rem
5673 -- if both operands can be negative.
5677 then
5678 declare
5685 -- Set if corresponding operand might be negative
5687 begin
5688 Determine_Range
5692 Determine_Range
5696 -- Check if we will be generating conditionals. There are two
5697 -- cases where that can happen, first for REM, the only case
5698 -- is largest negative integer mod -1, where the division can
5699 -- overflow, but we still have to give the right result. The
5700 -- front end generates a test for this annoying case. Here we
5701 -- just test if both operands can be negative (that's what the
5702 -- expander does, so we match its logic here).
5704 -- The second case is mod where either operand can be negative.
5705 -- In this case, the back end has to generate additional tests.
5708 or else
5710 then
5721 ------------------
5722 -- Resolve_Call --
5723 ------------------
5726 function Same_Or_Aliased_Subprograms
5729 -- Returns True if the subprogram entity S is the same as E or else
5730 -- S is an alias of E.
5732 ---------------------------------
5733 -- Same_Or_Aliased_Subprograms --
5734 ---------------------------------
5736 function Same_Or_Aliased_Subprograms
5739 is
5741 begin
5745 -- Local variables
5759 -- Start of processing for Resolve_Call
5761 begin
5762 -- Preserve relevant elaboration-related attributes of the context which
5763 -- are no longer available or very expensive to recompute once analysis,
5764 -- resolution, and expansion are over.
5766 Mark_Elaboration_Attributes
5772 -- The context imposes a unique interpretation with type Typ on a
5773 -- procedure or function call. Find the entity of the subprogram that
5774 -- yields the expected type, and propagate the corresponding formal
5775 -- constraints on the actuals. The caller has established that an
5776 -- interpretation exists, and emitted an error if not unique.
5778 -- First deal with the case of a call to an access-to-subprogram,
5779 -- dereference made explicit in Analyze_Call.
5785 else
5786 -- Find the interpretation whose type (a subprogram type) has a
5787 -- return type that is compatible with the context. Analysis of
5788 -- the node has established that one exists.
5807 -- If the prefix is not an entity, then resolve it
5813 -- For an indirect call, we always invalidate checks, since we do not
5814 -- know whether the subprogram is local or global. Yes we could do
5815 -- better here, e.g. by knowing that there are no local subprograms,
5816 -- but it does not seem worth the effort. Similarly, we kill all
5817 -- knowledge of current constant values.
5819 Kill_Current_Values;
5821 -- If this is a procedure call which is really an entry call, do
5822 -- the conversion of the procedure call to an entry call. Protected
5823 -- operations use the same circuitry because the name in the call
5824 -- can be an arbitrary expression with special resolution rules.
5829 then
5836 -- Annotate the tree by creating a call marker in case the original
5837 -- call is transformed by expansion. The call marker is automatically
5838 -- saved for later examination by the ABE Processing phase.
5842 -- Kill checks and constant values, as above for indirect case
5843 -- Who knows what happens when another task is activated?
5845 Kill_Current_Values;
5848 -- Normal subprogram call with name established in Resolve
5854 -- Otherwise we must have the case of an overloaded call
5856 else
5859 -- Initialize Nam to prevent warning (we know it will be assigned
5860 -- in the loop below, but the compiler does not know that).
5880 then
5881 -- The prefix is a parameterless function call that returns an access
5882 -- to subprogram. If parameters are present in the current call, add
5883 -- add an explicit dereference. We use the base type here because
5884 -- within an instance these may be subtypes.
5886 -- The dereference is added either in Analyze_Call or here. Should
5887 -- be consolidated ???
5896 -- Check that a call to Current_Task does not occur in an entry body
5899 declare
5902 begin
5904 loop
5907 -- Exclude calls that occur within the default of a formal
5908 -- parameter of the entry, since those are evaluated outside
5909 -- of the body.
5916 then
5919 Error_Msg_NE
5933 -- Check that a procedure call does not occur in the context of the
5934 -- entry call statement of a conditional or timed entry call. Note that
5935 -- the case of a call to a subprogram renaming of an entry will also be
5936 -- rejected. The test for N not being an N_Entry_Call_Statement is
5937 -- defensive, covering the possibility that the processing of entry
5938 -- calls might reach this point due to later modifications of the code
5939 -- above.
5944 then
5948 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5949 -- for a procedure_or_entry_call, the procedure_name or
5950 -- procedure_prefix of the procedure_call_statement shall denote
5951 -- an entry renamed by a procedure, or (a view of) a primitive
5952 -- subprogram of a limited interface whose first parameter is
5953 -- a controlling parameter.
5958 then
5959 Error_Msg_N
5964 -- If the SPARK_05 restriction is active, we are not allowed
5965 -- to have a call to a subprogram before we see its completion.
5970 -- Don't flag strange internal calls
5975 -- Only flag calls in extended main source
5980 -- Exclude enumeration literals from this processing
5983 then
5984 Check_SPARK_05_Restriction
5988 -- Check that this is not a call to a protected procedure or entry from
5989 -- within a protected function.
5993 -- Freeze the subprogram name if not in a spec-expression. Note that
5994 -- we freeze procedure calls as well as function calls. Procedure calls
5995 -- are not frozen according to the rules (RM 13.14(14)) because it is
5996 -- impossible to have a procedure call to a non-frozen procedure in
5997 -- pure Ada, but in the code that we generate in the expander, this
5998 -- rule needs extending because we can generate procedure calls that
5999 -- need freezing.
6001 -- In Ada 2012, expression functions may be called within pre/post
6002 -- conditions of subsequent functions or expression functions. Such
6003 -- calls do not freeze when they appear within generated bodies,
6004 -- (including the body of another expression function) which would
6005 -- place the freeze node in the wrong scope. An expression function
6006 -- is frozen in the usual fashion, by the appearance of a real body,
6007 -- or at the end of a declarative part.
6010 and then not In_Spec_Expression
6012 and then
6015 then
6019 -- For a predefined operator, the type of the result is the type imposed
6020 -- by context, except for a predefined operation on universal fixed.
6021 -- Otherwise The type of the call is the type returned by the subprogram
6022 -- being called.
6029 -- If the subprogram returns an array type, and the context requires the
6030 -- component type of that array type, the node is really an indexing of
6031 -- the parameterless call. Resolve as such. A pathological case occurs
6032 -- when the type of the component is an access to the array type. In
6033 -- this case the call is truly ambiguous. If the call is to an intrinsic
6034 -- subprogram, it can't be an indexed component. This check is necessary
6035 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6036 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6037 -- pointers to the same array), the compiler gets confused and does an
6038 -- infinite recursion.
6041 and then
6044 or else
6047 and then
6050 then
6051 declare
6056 begin
6059 then
6060 Error_Msg_N
6062 else
6065 -- The called entity may be an explicit dereference, in which
6066 -- case there is no entity to set.
6074 or else
6076 and then
6078 then
6081 -- Indexed call to a parameterless function
6083 Index_Node :=
6085 Prefix =>
6088 else
6089 -- An Ada 2005 prefixed call to a primitive operation
6090 -- whose first parameter is the prefix. This prefix was
6091 -- prepended to the parameter list, which is actually a
6092 -- list of indexes. Remove the prefix in order to build
6093 -- the proper indexed component.
6095 Index_Node :=
6097 Prefix =>
6100 Parameter_Associations =>
6101 New_List
6106 -- Preserve the parenthesis count of the node
6110 -- Since we are correcting a node classification error made
6111 -- by the parser, we call Replace rather than Rewrite.
6123 -- Annotate the tree by creating a call marker in case
6124 -- the original call is transformed by expansion. The call
6125 -- marker is automatically saved for later examination by
6126 -- the ABE Processing phase.
6135 else
6136 -- If the called function is not declared in the main unit and it
6137 -- returns the limited view of type then use the available view (as
6138 -- is done in Try_Object_Operation) to prevent back-end confusion;
6139 -- for the function entity itself. The call must appear in a context
6140 -- where the nonlimited view is available. If the function entity is
6141 -- in the extended main unit then no action is needed, because the
6142 -- back end handles this case. In either case the type of the call
6143 -- is the nonlimited view.
6147 then
6154 else
6159 -- In the case where the call is to an overloaded subprogram, Analyze
6160 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6161 -- such a case Normalize_Actuals needs to be called once more to order
6162 -- the actuals correctly. Otherwise the call will have the ordering
6163 -- given by the last overloaded subprogram whether this is the correct
6164 -- one being called or not.
6171 -- In any case, call is fully resolved now. Reset Overload flag, to
6172 -- prevent subsequent overload resolution if node is analyzed again
6177 -- A Ghost entity must appear in a specific context
6183 -- If we are calling the current subprogram from immediately within its
6184 -- body, then that is the case where we can sometimes detect cases of
6185 -- infinite recursion statically. Do not try this in case restriction
6186 -- No_Recursion is in effect anyway, and do it only for source calls.
6191 -- Check violation of SPARK_05 restriction which does not permit
6192 -- a subprogram body to contain a call to the subprogram directly.
6196 then
6197 Check_SPARK_05_Restriction
6201 -- Issue warning for possible infinite recursion in the absence
6202 -- of the No_Recursion restriction.
6207 then
6208 -- Here we detected and flagged an infinite recursion, so we do
6209 -- not need to test the case below for further warnings. Also we
6210 -- are all done if we now have a raise SE node.
6216 -- If call is to immediately containing subprogram, then check for
6217 -- the case of a possible run-time detectable infinite recursion.
6219 else
6223 -- Although in general case, recursion is not statically
6224 -- checkable, the case of calling an immediately containing
6225 -- subprogram is easy to catch.
6229 -- If the recursive call is to a parameterless subprogram,
6230 -- then even if we can't statically detect infinite
6231 -- recursion, this is pretty suspicious, and we output a
6232 -- warning. Furthermore, we will try later to detect some
6233 -- cases here at run time by expanding checking code (see
6234 -- Detect_Infinite_Recursion in package Exp_Ch6).
6236 -- If the recursive call is within a handler, do not emit a
6237 -- warning, because this is a common idiom: loop until input
6238 -- is correct, catch illegal input in handler and restart.
6244 then
6245 -- For the case of a procedure call. We give the message
6246 -- only if the call is the first statement in a sequence
6247 -- of statements, or if all previous statements are
6248 -- simple assignments. This is simply a heuristic to
6249 -- decrease false positives, without losing too many good
6250 -- warnings. The idea is that these previous statements
6251 -- may affect global variables the procedure depends on.
6252 -- We also exclude raise statements, that may arise from
6253 -- constraint checks and are probably unrelated to the
6254 -- intended control flow.
6258 then
6259 declare
6261 begin
6265 N_Raise_Constraint_Error)
6266 then
6275 -- Do not give warning if we are in a conditional context
6277 declare
6279 begin
6285 then
6290 -- Here warning is to be issued
6306 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6310 -- If subprogram name is a predefined operator, it was given in
6311 -- functional notation. Replace call node with operator node, so
6312 -- that actuals can be resolved appropriately.
6320 then
6326 -- Create a transient scope if the resulting type requires it
6328 -- There are several notable exceptions:
6330 -- a) In init procs, the transient scope overhead is not needed, and is
6331 -- even incorrect when the call is a nested initialization call for a
6332 -- component whose expansion may generate adjust calls. However, if the
6333 -- call is some other procedure call within an initialization procedure
6334 -- (for example a call to Create_Task in the init_proc of the task
6335 -- run-time record) a transient scope must be created around this call.
6337 -- b) Enumeration literal pseudo-calls need no transient scope
6339 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6340 -- functions) do not use the secondary stack even though the return
6341 -- type may be unconstrained.
6343 -- d) Calls to a build-in-place function, since such functions may
6344 -- allocate their result directly in a target object, and cases where
6345 -- the result does get allocated in the secondary stack are checked for
6346 -- within the specialized Exp_Ch6 procedures for expanding those
6347 -- build-in-place calls.
6349 -- e) Calls to inlinable expression functions do not use the secondary
6350 -- stack (since the call will be replaced by its returned object).
6352 -- f) If the subprogram is marked Inline_Always, then even if it returns
6353 -- an unconstrained type the call does not require use of the secondary
6354 -- stack. However, inlining will only take place if the body to inline
6355 -- is already present. It may not be available if e.g. the subprogram is
6356 -- declared in a child instance.
6362 then
6369 then
6372 elsif Expander_Active
6375 then
6378 -- If the call appears within the bounds of a loop, it will be
6379 -- rewritten and reanalyzed, nothing left to do here.
6386 -- A protected function cannot be called within the definition of the
6387 -- enclosing protected type, unless it is part of a pre/postcondition
6388 -- on another protected operation. This may appear in the entry wrapper
6389 -- created for an entry with preconditions.
6394 and then not In_Spec_Expression
6396 then
6397 Error_Msg_NE
6401 -- Propagate interpretation to actuals, and add default expressions
6402 -- where needed.
6407 -- Overloaded literals are rewritten as function calls, for purpose of
6408 -- resolution. After resolution, we can replace the call with the
6409 -- literal itself.
6415 -- Avoid validation, since it is a static function call
6421 -- If the subprogram is not global, then kill all saved values and
6422 -- checks. This is a bit conservative, since in many cases we could do
6423 -- better, but it is not worth the effort. Similarly, we kill constant
6424 -- values. However we do not need to do this for internal entities
6425 -- (unless they are inherited user-defined subprograms), since they
6426 -- are not in the business of molesting local values.
6428 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6429 -- kill all checks and values for calls to global subprograms. This
6430 -- takes care of the case where an access to a local subprogram is
6431 -- taken, and could be passed directly or indirectly and then called
6432 -- from almost any context.
6434 -- Note: we do not do this step till after resolving the actuals. That
6435 -- way we still take advantage of the current value information while
6436 -- scanning the actuals.
6438 -- We suppress killing values if we are processing the nodes associated
6439 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6440 -- type kills all the values as part of analyzing the code that
6441 -- initializes the dispatch tables.
6445 or else Suppress_Value_Tracking_On_Call
6450 then
6451 Kill_Current_Values;
6454 -- If we are warning about unread OUT parameters, this is the place to
6455 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6456 -- after the above call to Kill_Current_Values (since that call clears
6457 -- the Last_Assignment field of all local variables).
6462 then
6463 declare
6467 begin
6477 then
6487 -- If the subprogram is a primitive operation, check whether or not
6488 -- it is a correct dispatching call.
6492 then
6497 and then not In_Instance
6498 then
6502 -- If this is a dispatching call, generate the appropriate reference,
6503 -- for better source navigation in GPS.
6507 then
6510 -- Normal case, not a dispatching call: generate a call reference
6512 else
6520 -- Check for violation of restriction No_Specific_Termination_Handlers
6521 -- and warn on a potentially blocking call to Abort_Task.
6525 or else
6527 then
6534 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6535 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6536 -- need to check the second argument to determine whether it is an
6537 -- absolute or relative timing event.
6542 then
6546 -- Issue an error for a call to an eliminated subprogram. This routine
6547 -- will not perform the check if the call appears within a default
6548 -- expression.
6552 -- In formal mode, the primitive operations of a tagged type or type
6553 -- extension do not include functions that return the tagged type.
6559 then
6563 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6564 -- class-wide and the call dispatches on result in a context that does
6565 -- not provide a tag, the call raises Program_Error.
6568 and then In_Instance
6573 then
6574 -- Verify that none of the formals are controlling
6576 declare
6580 begin
6602 -- Check for calling a function with OUT or IN OUT parameter when the
6603 -- calling context (us right now) is not Ada 2012, so does not allow
6604 -- OUT or IN OUT parameters in function calls. Functions declared in
6605 -- a predefined unit are OK, as they may be called indirectly from a
6606 -- user-declared instantiation.
6612 then
6617 -- Check the dimensions of the actuals in the call. For function calls,
6618 -- propagate the dimensions from the returned type to N.
6622 -- All done, evaluate call and deal with elaboration issues
6630 -- Annotate the tree by creating a call marker in case the original call
6631 -- is transformed by expansion. The call marker is automatically saved
6632 -- for later examination by the ABE Processing phase.
6636 -- In GNATprove mode, expansion is disabled, but we want to inline some
6637 -- subprograms to facilitate formal verification. Indirect calls through
6638 -- a subprogram type or within a generic cannot be inlined. Inlining is
6639 -- performed only for calls subject to SPARK_Mode on.
6641 if GNATprove_Mode
6644 and then not Inside_A_Generic
6645 then
6652 -- Nothing to do if the subprogram is not eligible for inlining in
6653 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6657 or else Debug_Flag_M
6658 then
6661 -- Calls cannot be inlined inside assertions, as GNATprove treats
6662 -- assertions as logic expressions. Only issue a message when the
6663 -- body has been seen, otherwise this leads to spurious messages
6664 -- on expression functions.
6668 Cannot_Inline
6672 -- Calls cannot be inlined inside default expressions
6675 Cannot_Inline
6678 -- Inlining should not be performed during pre-analysis
6682 -- Do not inline calls inside expression functions, as this
6683 -- would prevent interpreting them as logical formulas in
6684 -- GNATprove. Only issue a message when the body has been seen,
6685 -- otherwise this leads to spurious messages on callees that
6686 -- are themselves expression functions.
6689 and then Is_Expression_Function_Or_Completion
6691 then
6694 then
6695 Cannot_Inline
6700 -- With the one-pass inlining technique, a call cannot be
6701 -- inlined if the corresponding body has not been seen yet.
6704 Cannot_Inline
6707 -- Nothing to do if there is no body to inline, indicating that
6708 -- the subprogram is not suitable for inlining in GNATprove
6709 -- mode.
6714 -- Calls cannot be inlined inside potentially unevaluated
6715 -- expressions, as this would create complex actions inside
6716 -- expressions, that are not handled by GNATprove.
6719 Cannot_Inline
6723 -- Do not inline calls which would possibly lead to missing a
6724 -- type conversion check on an input parameter.
6727 Cannot_Inline
6731 -- Otherwise, inline the call
6733 else
6745 -----------------------------
6746 -- Resolve_Case_Expression --
6747 -----------------------------
6755 begin
6767 -- When the expression is of a scalar subtype different from the
6768 -- result subtype, then insert a conversion to ensure the generation
6769 -- of a constraint check.
6779 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6780 -- dynamically tagged must be known statically.
6788 Error_Msg_N
6802 -------------------------------
6803 -- Resolve_Character_Literal --
6804 -------------------------------
6810 begin
6811 -- Verify that the character does belong to the type of the context
6816 -- Wide_Wide_Character literals must always be defined, since the set
6817 -- of wide wide character literals is complete, i.e. if a character
6818 -- literal is accepted by the parser, then it is OK for wide wide
6819 -- character (out of range character literals are rejected).
6824 -- Always accept character literal for type Any_Character, which
6825 -- occurs in error situations and in comparisons of literals, both
6826 -- of which should accept all literals.
6831 -- For Standard.Character or a type derived from it, check that the
6832 -- literal is in range.
6839 -- For Standard.Wide_Character or a type derived from it, check that the
6840 -- literal is in range.
6847 -- If the entity is already set, this has already been resolved in a
6848 -- generic context, or comes from expansion. Nothing else to do.
6853 -- Otherwise we have a user defined character type, and we can use the
6854 -- standard visibility mechanisms to locate the referenced entity.
6856 else
6869 -- If we fall through, then the literal does not match any of the
6870 -- entries of the enumeration type. This isn't just a constraint error
6871 -- situation, it is an illegality (see RM 4.2).
6873 Error_Msg_NE
6877 ---------------------------
6878 -- Resolve_Comparison_Op --
6879 ---------------------------
6881 -- Context requires a boolean type, and plays no role in resolution.
6882 -- Processing identical to that for equality operators. The result type is
6883 -- the base type, which matters when pathological subtypes of booleans with
6884 -- limited ranges are used.
6891 begin
6892 -- If this is an intrinsic operation which is not predefined, use the
6893 -- types of its declared arguments to resolve the possibly overloaded
6894 -- operands. Otherwise the operands are unambiguous and specify the
6895 -- expected type.
6900 else
6911 -- Skip remaining processing if already set to Any_Type
6917 -- Deal with other error cases
6921 T = Any_Character
6922 then
6925 else
6933 -- Resolve the operands if types OK
6942 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6943 -- types or array types except String.
6946 Check_SPARK_05_Restriction
6951 then
6952 Check_SPARK_05_Restriction
6956 -- Check comparison on unordered enumeration
6960 Error_Msg_NE
6967 -- Evaluate the relation (note we do this after the above check since
6968 -- this Eval call may change N to True/False. Skip this evaluation
6969 -- inside assertions, in order to keep assertions as written by users
6970 -- for tools that rely on these, e.g. GNATprove for loop invariants.
6971 -- Except evaluation is still performed even inside assertions for
6972 -- comparisons between values of universal type, which are useless
6973 -- for static analysis tools, and not supported even by GNATprove.
6977 and then
6979 then
6984 -----------------------------------------
6985 -- Resolve_Discrete_Subtype_Indication --
6986 -----------------------------------------
6988 procedure Resolve_Discrete_Subtype_Indication
6991 is
6995 begin
7003 else
7013 Error_Msg_NE
7016 -- Rewrite the constraint as a range of Typ
7017 -- to allow compilation to proceed further.
7029 else
7033 -- Additionally, we must check that the bounds are compatible
7034 -- with the given subtype, which might be different from the
7035 -- type of the context.
7039 -- ??? If the above check statically detects a Constraint_Error
7040 -- it replaces the offending bound(s) of the range R with a
7041 -- Constraint_Error node. When the itype which uses these bounds
7042 -- is frozen the resulting call to Duplicate_Subexpr generates
7043 -- a new temporary for the bounds.
7045 -- Unfortunately there are other itypes that are also made depend
7046 -- on these bounds, so when Duplicate_Subexpr is called they get
7047 -- a forward reference to the newly created temporaries and Gigi
7048 -- aborts on such forward references. This is probably sign of a
7049 -- more fundamental problem somewhere else in either the order of
7050 -- itype freezing or the way certain itypes are constructed.
7052 -- To get around this problem we call Remove_Side_Effects right
7053 -- away if either bounds of R are a Constraint_Error.
7055 declare
7059 begin
7075 -------------------------
7076 -- Resolve_Entity_Name --
7077 -------------------------
7079 -- Used to resolve identifiers and expanded names
7082 function Is_Assignment_Or_Object_Expression
7085 -- Determine whether node Context denotes an assignment statement or an
7086 -- object declaration whose expression is node Expr.
7088 ----------------------------------------
7089 -- Is_Assignment_Or_Object_Expression --
7090 ----------------------------------------
7092 function Is_Assignment_Or_Object_Expression
7095 is
7096 begin
7098 N_Object_Declaration)
7100 then
7103 -- Check whether a construct that yields a name is the expression of
7104 -- an assignment statement or an object declaration.
7107 N_Explicit_Dereference,
7108 N_Indexed_Component,
7109 N_Selected_Component,
7110 N_Slice)
7112 or else
7114 N_Unchecked_Type_Conversion)
7116 then
7117 return
7118 Is_Assignment_Or_Object_Expression
7122 -- Otherwise the context is not an assignment statement or an object
7123 -- declaration.
7125 else
7130 -- Local variables
7135 -- Start of processing for Resolve_Entity_Name
7137 begin
7138 -- If garbage from errors, set to Any_Type and return
7145 -- Replace named numbers by corresponding literals. Note that this is
7146 -- the one case where Resolve_Entity_Name must reset the Etype, since
7147 -- it is currently marked as universal.
7157 -- For enumeration literals, we need to make sure that a proper style
7158 -- check is done, since such literals are overloaded, and thus we did
7159 -- not do a style check during the first phase of analysis.
7165 -- Case of (sub)type name appearing in a context where an expression
7166 -- is expected. This is legal if occurrence is a current instance.
7167 -- See RM 8.6 (17/3).
7173 -- Any other use is an error
7175 else
7176 Error_Msg_N
7180 -- Check discriminant use if entity is discriminant in current scope,
7181 -- i.e. discriminant of record or concurrent type currently being
7182 -- analyzed. Uses in corresponding body are unrestricted.
7187 then
7190 -- A parameterless generic function cannot appear in a context that
7191 -- requires resolution.
7196 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7197 -- array types (i.e. bounds and length) are legal.
7205 or else Is_Assignment_Or_Object_Expression
7208 then
7213 -- In all other cases, just do the possible static evaluation
7215 else
7216 -- A deferred constant that appears in an expression must have a
7217 -- completion, unless it has been removed by in-place expansion of
7218 -- an aggregate. A constant that is a renaming does not need
7219 -- initialization.
7225 and then not In_Spec_Expression
7228 then
7232 then
7234 else
7235 Error_Msg_N
7245 -- When the entity appears in a parameter association, retrieve the
7246 -- related subprogram call.
7254 -- The following checks are only relevant when SPARK_Mode is on as
7255 -- they are not standard Ada legality rules.
7259 -- An effectively volatile object subject to enabled properties
7260 -- Async_Writers or Effective_Reads must appear in non-interfering
7261 -- context (SPARK RM 7.1.3(12)).
7268 then
7269 SPARK_Msg_N
7274 -- Check for possible elaboration issues with respect to reads of
7275 -- variables. The act of renaming the variable is not considered a
7276 -- read as it simply establishes an alias.
7278 if Legacy_Elaboration_Checks
7280 and then Dynamic_Elaboration_Checks
7282 then
7287 -- The variable may eventually become a constituent of a single
7288 -- protected/task type. Record the reference now and verify its
7289 -- legality when analyzing the contract of the variable
7290 -- (SPARK RM 9.3).
7296 -- A Ghost entity must appear in a specific context
7306 -------------------
7307 -- Resolve_Entry --
7308 -------------------
7320 -- If the bounds of the entry family being called depend on task
7321 -- discriminants, build a new index subtype where a discriminant is
7322 -- replaced with the value of the discriminant of the target task.
7323 -- The target task is the prefix of the entry name in the call.
7325 -----------------------
7326 -- Actual_Index_Type --
7327 -----------------------
7337 -- If the bound is given by a discriminant, replace with a reference
7338 -- to the discriminant of the same name in the target task. If the
7339 -- entry name is the target of a requeue statement and the entry is
7340 -- in the current protected object, the bound to be used is the
7341 -- discriminal of the object (see Apply_Range_Checks for details of
7342 -- the transformation).
7344 -----------------------------
7345 -- Actual_Discriminant_Ref --
7346 -----------------------------
7352 begin
7357 then
7363 then
7364 -- Note: here Bound denotes a discriminant of the corresponding
7365 -- record type tskV, whose discriminal is a formal of the
7366 -- init-proc tskVIP. What we want is the body discriminal,
7367 -- which is associated to the discriminant of the original
7368 -- concurrent type tsk.
7370 return New_Occurrence_Of
7373 else
7374 Ref :=
7384 -- Start of processing for Actual_Index_Type
7386 begin
7389 then
7392 else
7406 -- Start of processing for Resolve_Entry
7408 begin
7409 -- Find name of entry being called, and resolve prefix of name with its
7410 -- own type. The prefix can be overloaded, and the name and signature of
7411 -- the entry must be taken into account.
7415 -- Case of dealing with entry family within the current tasks
7419 else
7425 -- Entry call to an entry (or entry family) in the current task. This
7426 -- is legal even though the task will deadlock. Rewrite as call to
7427 -- current task.
7429 -- This can also be a call to an entry in an enclosing task. If this
7430 -- is a single task, we have to retrieve its name, because the scope
7431 -- of the entry is the task type, not the object. If the enclosing
7432 -- task is a task type, the identity of the task is given by its own
7433 -- self variable.
7435 -- Finally this can be a requeue on an entry of the same task or
7436 -- protected object.
7443 then
7444 -- S is an enclosing task or protected object. The concurrent
7445 -- declaration has been converted into a type declaration, and
7446 -- the object itself has an object declaration that follows
7447 -- the type in the same declarative part.
7459 -- Call to current task. Will be transformed into call to Self
7466 New_N :=
7469 Selector_Name =>
7476 then
7477 -- Use the entry name (which must be unique at this point) to find
7478 -- the prefix that returns the corresponding task/protected type.
7480 declare
7486 begin
7508 -- Generate a reference for the index when it denotes an entity
7514 -- Up to this point the expression could have been the actual in a
7515 -- simple entry call, and be given by a named association.
7519 else
7525 ------------------------
7526 -- Resolve_Entry_Call --
7527 ------------------------
7538 begin
7539 -- We kill all checks here, because it does not seem worth the effort to
7540 -- do anything better, an entry call is a big operation.
7542 Kill_All_Checks;
7544 -- Processing of the name is similar for entry calls and protected
7545 -- operation calls. Once the entity is determined, we can complete
7546 -- the resolution of the actuals.
7548 -- The selector may be overloaded, in the case of a protected object
7549 -- with overloaded functions. The type of the context is used for
7550 -- resolution.
7555 then
7556 declare
7560 begin
7579 -- Simple entry or protected operation call
7592 -- Call to member of entry family
7599 -- We cannot in general check the maximum depth of protected entry calls
7600 -- at compile time. But we can tell that any protected entry call at all
7601 -- violates a specified nesting depth of zero.
7607 -- Use context type to disambiguate a protected function that can be
7608 -- called without actuals and that returns an array type, and where the
7609 -- argument list may be an indexing of the returned value.
7614 and then
7620 and then
7621 Covers
7624 then
7625 declare
7628 begin
7629 Index_Node :=
7631 Prefix =>
7635 -- Since we are correcting a node classification error made by the
7636 -- parser, we call Replace rather than Rewrite.
7649 then
7650 -- Note the entity being called before rewriting the call, so that
7651 -- it appears used at this point.
7655 -- Rewrite as call to the precondition wrapper, adding the task
7656 -- object to the list of actuals. If the call is to a member of an
7657 -- entry family, include the index as well.
7659 declare
7663 begin
7672 New_Call :=
7674 Name =>
7679 -- Preanalyze and resolve new call. Current procedure is called
7680 -- from Resolve_Call, after which expansion will take place.
7687 -- The operation name may have been overloaded. Order the actuals
7688 -- according to the formals of the resolved entity, and set the return
7689 -- type to that of the operation.
7696 -- Reset the Is_Overloaded flag, since resolution is now completed
7698 -- Simple entry call
7703 -- Call to a member of an entry family
7713 -- Create a call reference to the entry
7721 -- Verify that a procedure call cannot masquerade as an entry
7722 -- call where an entry call is expected.
7727 then
7732 then
7737 then
7742 -- After resolution, entry calls and protected procedure calls are
7743 -- changed into entry calls, for expansion. The structure of the node
7744 -- does not change, so it can safely be done in place. Protected
7745 -- function calls must keep their structure because they are
7746 -- subexpressions.
7750 -- A protected operation that is not a function may modify the
7751 -- corresponding object, and cannot apply to a constant. If this
7752 -- is an internal call, the prefix is the type itself.
7758 then
7759 Error_Msg_N
7761 Entry_Name);
7764 declare
7767 begin
7768 Entry_Call :=
7773 -- Inherit relevant attributes from the original call
7775 Set_First_Named_Actual
7778 Set_Is_Elaboration_Checks_OK_Node
7781 Set_Is_Elaboration_Warnings_OK_Node
7784 Set_Is_SPARK_Mode_On_Node
7791 -- Protected functions can return on the secondary stack, in which case
7792 -- we must trigger the transient scope mechanism.
7794 elsif Expander_Active
7796 then
7801 -------------------------
7802 -- Resolve_Equality_Op --
7803 -------------------------
7805 -- Both arguments must have the same type, and the boolean context does
7806 -- not participate in the resolution. The first pass verifies that the
7807 -- interpretation is not ambiguous, and the type of the left argument is
7808 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7809 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7810 -- though they carry a single (universal) type. Diagnose this case here.
7818 -- The resolution rule for if expressions requires that each such must
7819 -- have a unique type. This means that if several dependent expressions
7820 -- are of a non-null anonymous access type, and the context does not
7821 -- impose an expected type (as can be the case in an equality operation)
7822 -- the expression must be rejected.
7825 -- Attempt to explain the nature of a redundant comparison with True. If
7826 -- the expression N is too complex, this routine issues a general error
7827 -- message.
7830 -- In the case of allocators and access attributes, the context must
7831 -- provide an indication of the specific access type to be used. If
7832 -- one operand is of such a "generic" access type, check whether there
7833 -- is a specific visible access type that has the same designated type.
7834 -- This is semantically dubious, and of no interest to any real code,
7835 -- but c48008a makes it all worthwhile.
7837 -------------------------
7838 -- Check_If_Expression --
7839 -------------------------
7845 begin
7852 then
7858 ------------------------
7859 -- Explain_Redundancy --
7860 ------------------------
7867 begin
7870 -- Strip the operand down to an entity
7872 loop
7875 else
7880 -- The construct denotes an entity
7885 -- Do not generate an error message when the comparison is done
7886 -- against the enumeration literal Standard.True.
7890 -- Build a customized error message
7917 -- The construct is too complex to disect, issue a general message
7919 else
7924 -----------------------------
7925 -- Find_Unique_Access_Type --
7926 -----------------------------
7933 begin
7935 E_Access_Attribute_Type)
7936 then
7940 E_Access_Attribute_Type)
7941 then
7943 else
7955 then
7968 -- Start of processing for Resolve_Equality_Op
7970 begin
7981 T = Any_Character
7982 then
7985 else
7994 then
8003 -- If expressions must have a single type, and if the context does
8004 -- not impose one the dependent expressions cannot be anonymous
8005 -- access types.
8007 -- Why no similar processing for case expressions???
8011 E_Anonymous_Access_Subprogram_Type)
8013 E_Anonymous_Access_Subprogram_Type)
8014 then
8022 -- In SPARK, equality operators = and /= for array types other than
8023 -- String are only defined when, for each index position, the
8024 -- operands have equal static bounds.
8028 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8029 -- operation if not needed.
8037 then
8038 Check_SPARK_05_Restriction
8043 -- If the unique type is a class-wide type then it will be expanded
8044 -- into a dispatching call to the predefined primitive. Therefore we
8045 -- check here for potential violation of such restriction.
8051 -- Only warn for redundant equality comparison to True for objects
8052 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8053 -- other expressions, it may be a matter of preference to write
8054 -- "Expr = True" or "Expr".
8056 if Warn_On_Redundant_Constructs
8061 and then
8063 or else
8065 then
8066 Error_Msg_N -- CODEFIX
8076 -- If this is an inequality, it may be the implicit inequality
8077 -- created for a user-defined operation, in which case the corres-
8078 -- ponding equality operation is not intrinsic, and the operation
8079 -- cannot be constant-folded. Else fold.
8084 or else Is_Intrinsic_Subprogram
8086 then
8092 then
8096 -- Ada 2005: If one operand is an anonymous access type, convert the
8097 -- other operand to it, to ensure that the underlying types match in
8098 -- the back-end. Same for access_to_subprogram, and the conversion
8099 -- verifies that the types are subtype conformant.
8101 -- We apply the same conversion in the case one of the operands is a
8102 -- private subtype of the type of the other.
8104 -- Why the Expander_Active test here ???
8106 if Expander_Active
8107 and then
8109 E_Anonymous_Access_Subprogram_Type)
8111 then
8131 ----------------------------------
8132 -- Resolve_Explicit_Dereference --
8133 ----------------------------------
8141 -- The candidate prefix type, if overloaded
8146 begin
8150 -- A useful optimization: check whether the dereference denotes an
8151 -- element of a container, and if so rewrite it as a call to the
8152 -- corresponding Element function.
8154 -- Disabled for now, on advice of ARG. A more restricted form of the
8155 -- predicate might be acceptable ???
8157 -- if Is_Container_Element (N) then
8158 -- return;
8159 -- end if;
8163 -- Use the context type to select the prefix that has the correct
8164 -- designated type. Keep the first match, which will be the inner-
8165 -- most.
8172 then
8177 -- Remove access types that do not match, but preserve access
8178 -- to subprogram interpretations, in case a further dereference
8179 -- is needed (see below).
8192 else
8193 -- If no interpretation covers the designated type of the prefix,
8194 -- this is the pathological case where not all implementations of
8195 -- the prefix allow the interpretation of the node as a call. Now
8196 -- that the expected type is known, Remove other interpretations
8197 -- from prefix, rewrite it as a call, and resolve again, so that
8198 -- the proper call node is generated.
8209 New_N :=
8211 Name =>
8222 -- If not overloaded, resolve P with its own type
8224 else
8228 -- If the prefix might be null, add an access check
8232 then
8236 -- If the designated type is a packed unconstrained array type, and the
8237 -- explicit dereference is not in the context of an attribute reference,
8238 -- then we must compute and set the actual subtype, since it is needed
8239 -- by Gigi. The reason we exclude the attribute case is that this is
8240 -- handled fine by Gigi, and in fact we use such attributes to build the
8241 -- actual subtype. We also exclude generated code (which builds actual
8242 -- subtypes directly if they are needed).
8249 then
8255 -- Note: No Eval processing is required for an explicit dereference,
8256 -- because such a name can never be static.
8260 -------------------------------------
8261 -- Resolve_Expression_With_Actions --
8262 -------------------------------------
8265 begin
8268 -- If N has no actions, and its expression has been constant folded,
8269 -- then rewrite N as just its expression. Note, we can't do this in
8270 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8271 -- Expression (N) to be expanded again.
8275 then
8280 ----------------------------------
8281 -- Resolve_Generalized_Indexing --
8282 ----------------------------------
8290 begin
8291 -- In ASIS mode, propagate the information about the indexes back to
8292 -- to the original indexing node. The generalized indexing is either
8293 -- a function call, or a dereference of one. The actuals include the
8294 -- prefix of the original node, which is the container expression.
8303 loop
8312 -- If expression is to be reanalyzed, reset Generalized_Indexing
8313 -- to recreate call node, as is the case when the expression is
8314 -- part of an expression function.
8323 else
8329 ---------------------------
8330 -- Resolve_If_Expression --
8331 ---------------------------
8340 begin
8341 -- Defend against malformed expressions
8359 -- When the "then" expression is of a scalar subtype different from the
8360 -- result subtype, then insert a conversion to ensure the generation of
8361 -- a constraint check. The same is done for the else part below, again
8362 -- comparing subtypes rather than base types.
8369 -- If ELSE expression present, just resolve using the determined type
8370 -- If type is universal, resolve to any member of the class.
8379 else
8389 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8390 -- dynamically tagged must be known statically.
8395 then
8401 -- If no ELSE expression is present, root type must be Standard.Boolean
8402 -- and we provide a Standard.True result converted to the appropriate
8403 -- Boolean type (in case it is a derived boolean type).
8406 Else_Expr :=
8411 else
8425 -------------------------------
8426 -- Resolve_Indexed_Component --
8427 -------------------------------
8435 begin
8443 -- Use the context type to select the prefix that yields the correct
8444 -- component type.
8446 declare
8453 begin
8460 and then
8461 Covers
8464 then
8473 else
8479 else
8490 else
8497 -- If prefix is access type, dereference to get real array type.
8498 -- Note: we do not apply an access check because the expander always
8499 -- introduces an explicit dereference, and the check will happen there.
8505 -- If name was overloaded, set component type correctly now
8506 -- If a misplaced call to an entry family (which has no index types)
8507 -- return. Error will be diagnosed from calling context.
8511 else
8518 -- The prefix may have resolved to a string literal, in which case its
8519 -- etype has a special representation. This is only possible currently
8520 -- if the prefix is a static concatenation, written in functional
8521 -- notation.
8526 else
8533 else
8544 -- Do not generate the warning on suspicious index if we are analyzing
8545 -- package Ada.Tags; otherwise we will report the warning with the
8546 -- Prims_Ptr field of the dispatch table.
8549 or else not
8551 Ada_Tags)
8552 then
8557 -- If the array type is atomic, and the component is not atomic, then
8558 -- this is worth a warning, since we have a situation where the access
8559 -- to the component may cause extra read/writes of the atomic array
8560 -- object, or partial word accesses, which could be unexpected.
8566 and then Has_Atomic_Components
8569 then
8570 Error_Msg_N
8572 Error_Msg_N
8577 -----------------------------
8578 -- Resolve_Integer_Literal --
8579 -----------------------------
8582 begin
8587 --------------------------------
8588 -- Resolve_Intrinsic_Operator --
8589 --------------------------------
8598 -- If the operand is a literal, it cannot be the expression in a
8599 -- conversion. Use a qualified expression instead.
8601 ---------------------
8602 -- Convert_Operand --
8603 ---------------------
8609 begin
8611 Res :=
8617 else
8624 -- Start of processing for Resolve_Intrinsic_Operator
8626 begin
8627 -- We must preserve the original entity in a generic setting, so that
8628 -- the legality of the operation can be verified in an instance.
8643 -- If the result or operand types are private, rewrite with unchecked
8644 -- conversions on the operands and the result, to expose the proper
8645 -- underlying numeric type.
8650 then
8655 else
8676 then
8677 -- Add explicit conversion where needed, and save interpretations in
8678 -- case operands are overloaded.
8685 else
8691 else
8701 else
8706 --------------------------------------
8707 -- Resolve_Intrinsic_Unary_Operator --
8708 --------------------------------------
8710 procedure Resolve_Intrinsic_Unary_Operator
8713 is
8718 begin
8737 else
8742 ------------------------
8743 -- Resolve_Logical_Op --
8744 ------------------------
8749 begin
8752 -- Predefined operations on scalar types yield the base type. On the
8753 -- other hand, logical operations on arrays yield the type of the
8754 -- arguments (and the context).
8758 else
8762 -- The following test is required because the operands of the operation
8763 -- may be literals, in which case the resulting type appears to be
8764 -- compatible with a signed integer type, when in fact it is compatible
8765 -- only with modular types. If the context itself is universal, the
8766 -- operation is illegal.
8774 Error_Msg_N
8782 then
8786 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8787 -- is active and the result type is standard Boolean (do not mess with
8788 -- ops that return a nonstandard Boolean type, because something strange
8789 -- is going on).
8791 -- Note: you might expect this replacement to be done during expansion,
8792 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8793 -- is used, no part of the right operand of an "and" or "or" operator
8794 -- should be executed if the left operand would short-circuit the
8795 -- evaluation of the corresponding "and then" or "or else". If we left
8796 -- the replacement to expansion time, then run-time checks associated
8797 -- with such operands would be evaluated unconditionally, due to being
8798 -- before the condition prior to the rewriting as short-circuit forms
8799 -- during expansion.
8801 if Short_Circuit_And_Or
8804 then
8805 -- Mark the corresponding putative SCO operator as truly a logical
8806 -- (and short-circuit) operator.
8819 -- Case of OR changed to OR ELSE
8821 else
8829 -- Return now, since analysis of the rewritten ops will take care of
8830 -- other reference bookkeeping and expression folding.
8845 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8846 -- only when both operands have same static lower and higher bounds. Of
8847 -- course the types have to match, so only check if operands are
8848 -- compatible and the node itself has no errors.
8852 then
8853 declare
8857 begin
8858 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8859 -- operation if not needed.
8866 then
8867 Check_SPARK_05_Restriction
8874 ---------------------------
8875 -- Resolve_Membership_Op --
8876 ---------------------------
8878 -- The context can only be a boolean type, and does not determine the
8879 -- arguments. Arguments should be unambiguous, but the preference rule for
8880 -- universal types applies.
8890 -- Analysis has determined a unique type for the left operand. Use it to
8891 -- resolve the disjuncts.
8893 ----------------------------
8894 -- Resolve_Set_Membership --
8895 ----------------------------
8901 begin
8902 -- If the left operand is overloaded, find type compatible with not
8903 -- overloaded alternative of the right operand.
8912 else
8917 -- Unclear how to resolve expression if all alternatives are also
8918 -- overloaded.
8924 else
8933 -- Alternative is an expression, a range
8934 -- or a subtype mark.
8938 then
8945 -- Check for duplicates for discrete case
8948 declare
8957 begin
8958 -- Loop checking duplicates. This is quadratic, but giant sets
8959 -- are unlikely in this context so it's a reasonable choice.
8966 N_Character_Literal)
8968 then
8985 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
8986 -- limited types, evaluation of a membership test uses the predefined
8987 -- equality for the type. This may be confusing to users, and the
8988 -- following warning appears useful for the most common case.
8992 then
8993 Error_Msg_NE
8995 Error_Msg_N
9000 -- Start of processing for Resolve_Membership_Op
9002 begin
9008 Resolve_Set_Membership;
9012 and then
9014 or else
9017 then
9020 -- Ada 2005 (AI-251): Support the following case:
9022 -- type I is interface;
9023 -- type T is tagged ...
9025 -- function Test (O : I'Class) is
9026 -- begin
9027 -- return O in T'Class.
9028 -- end Test;
9030 -- In this case we have nothing else to do. The membership test will be
9031 -- done at run time.
9038 then
9040 else
9044 -- If mixed-mode operations are present and operands are all literal,
9045 -- the only interpretation involves Duration, which is probably not
9046 -- the intention of the programmer.
9061 then
9067 else
9072 -- Here after resolving membership operation
9079 ------------------
9080 -- Resolve_Null --
9081 ------------------
9086 begin
9087 -- Handle restriction against anonymous null access values This
9088 -- restriction can be turned off using -gnatdj.
9090 -- Ada 2005 (AI-231): Remove restriction
9093 and then not Debug_Flag_J
9096 then
9097 -- In the common case of a call which uses an explicitly null value
9098 -- for an access parameter, give specialized error message.
9101 Error_Msg_N
9104 -- Standard message for all other cases (are there any?)
9106 else
9107 Error_Msg_N
9112 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9113 -- assignment to a null-excluding object
9118 then
9120 Insert_Action
9125 else
9132 -- In a distributed context, null for a remote access to subprogram may
9133 -- need to be replaced with a special record aggregate. In this case,
9134 -- return after having done the transformation.
9139 then
9143 -- The null literal takes its type from the context
9148 -----------------------
9149 -- Resolve_Op_Concat --
9150 -----------------------
9154 -- We wish to avoid deep recursion, because concatenations are often
9155 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9156 -- operands nonrecursively until we find something that is not a simple
9157 -- concatenation (A in this case). We resolve that, and then walk back
9158 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9159 -- to do the rest of the work at each level. The Parent pointers allow
9160 -- us to avoid recursion, and thus avoid running out of memory. See also
9161 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9166 begin
9167 -- The following code is equivalent to:
9169 -- Resolve_Op_Concat_First (NN, Typ);
9170 -- Resolve_Op_Concat_Arg (N, ...);
9171 -- Resolve_Op_Concat_Rest (N, Typ);
9173 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9174 -- operand is a concatenation.
9176 -- Walk down left operands
9178 loop
9187 -- Now (given the above example) NN is A&B and Op1 is A
9189 -- First resolve Op1 ...
9193 -- ... then walk NN back up until we reach N (where we started), calling
9194 -- Resolve_Op_Concat_Rest along the way.
9196 loop
9203 Check_SPARK_05_Restriction
9208 ---------------------------
9209 -- Resolve_Op_Concat_Arg --
9210 ---------------------------
9212 procedure Resolve_Op_Concat_Arg
9217 is
9221 begin
9223 if Is_Comp
9227 then
9229 else
9233 -- If both Array & Array and Array & Component are visible, there is a
9234 -- potential ambiguity that must be reported.
9239 then
9243 -- If the operation is user-defined and not overloaded use its
9244 -- profile. The operation may be a renaming, in which case it has
9245 -- been rewritten, and we want the original profile.
9250 then
9252 Etype
9256 -- Otherwise an aggregate may match both the array type and the
9257 -- component type.
9259 else
9264 else
9268 then
9269 declare
9274 begin
9279 -- Special-case the error message when the overloading is
9280 -- caused by a function that yields an array and can be
9281 -- called without parameters.
9286 Error_Msg_NE
9288 Error_Msg_NE
9292 else
9300 or else
9302 then
9303 Error_Msg_N -- CODEFIX
9321 else
9326 else
9330 -- Concatenation is restricted in SPARK: each operand must be either a
9331 -- string literal, the name of a string constant, a static character or
9332 -- string expression, or another concatenation. Arg cannot be a
9333 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9334 -- separately on each final operand, past concatenation operations.
9338 Check_SPARK_05_Restriction
9346 then
9347 Check_SPARK_05_Restriction
9351 -- Do not issue error on an operand that is neither a character nor a
9352 -- string, as the error is issued in Resolve_Op_Concat.
9354 else
9361 -----------------------------
9362 -- Resolve_Op_Concat_First --
9363 -----------------------------
9370 begin
9371 -- The parser folds an enormous sequence of concatenations of string
9372 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9373 -- in the right operand. If the expression resolves to a predefined "&"
9374 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9375 -- we give an error. See P_Simple_Expression in Par.Ch4.
9380 then
9395 ----------------------------
9396 -- Resolve_Op_Concat_Rest --
9397 ----------------------------
9403 begin
9412 -- If this is not a static concatenation, but the result is a string
9413 -- type (and not an array of strings) ensure that static string operands
9414 -- have their subtypes properly constructed.
9418 then
9424 ----------------------
9425 -- Resolve_Op_Expon --
9426 ----------------------
9431 begin
9432 -- Catch attempts to do fixed-point exponentiation with universal
9433 -- operands, which is a case where the illegality is not caught during
9434 -- normal operator analysis. This is not done in preanalysis mode
9435 -- since the tree is not fully decorated during preanalysis.
9447 then
9457 then
9464 then
9468 -- We do the resolution using the base type, because intermediate values
9469 -- in expressions are always of the base type, not a subtype of it.
9474 -- For integer types, right argument must be in Natural range
9489 -- Evaluate the exponentiation operator for dimensioned type
9492 else
9496 -- Set overflow checking bit. Much cleverer code needed here eventually
9497 -- and perhaps the Resolve routines should be separated for the various
9498 -- arithmetic operations, since they will need different processing. ???
9507 --------------------
9508 -- Resolve_Op_Not --
9509 --------------------
9515 -- This function determines if the parent node is a boolean operator or
9516 -- operation (comparison op, membership test, or short circuit form) and
9517 -- the not in question is the left operand of this operation. Note that
9518 -- if the not is in parens, then false is returned.
9520 -----------------------
9521 -- Parent_Is_Boolean --
9522 -----------------------
9525 begin
9529 else
9531 when N_And_Then
9532 | N_In
9533 | N_Not_In
9534 | N_Op_And
9535 | N_Op_Eq
9536 | N_Op_Ge
9537 | N_Op_Gt
9538 | N_Op_Le
9539 | N_Op_Lt
9540 | N_Op_Ne
9541 | N_Op_Or
9542 | N_Op_Xor
9543 | N_Or_Else
9544 =>
9553 -- Start of processing for Resolve_Op_Not
9555 begin
9556 -- Predefined operations on scalar types yield the base type. On the
9557 -- other hand, logical operations on arrays yield the type of the
9558 -- arguments (and the context).
9562 else
9566 -- Straightforward case of incorrect arguments
9573 -- Special case of probable missing parens
9577 Error_Msg_N
9580 else
9581 Error_Msg_N
9588 -- OK resolution of NOT
9590 else
9591 -- Warn if non-boolean types involved. This is a case like not a < b
9592 -- where a and b are modular, where we will get (not a) < b and most
9593 -- likely not (a < b) was intended.
9595 if Warn_On_Questionable_Missing_Parens
9597 and then Parent_Is_Boolean
9598 then
9602 -- Warn on double negation if checking redundant constructs
9604 if Warn_On_Redundant_Constructs
9609 then
9613 -- Complete resolution and evaluation of NOT
9623 -----------------------------
9624 -- Resolve_Operator_Symbol --
9625 -----------------------------
9627 -- Nothing to be done, all resolved already
9633 begin
9637 ----------------------------------
9638 -- Resolve_Qualified_Expression --
9639 ----------------------------------
9647 begin
9650 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9651 -- operation if not needed.
9658 then
9659 Check_SPARK_05_Restriction
9663 -- A qualified expression requires an exact match of the type, class-
9664 -- wide matching is not allowed. However, if the qualifying type is
9665 -- specific and the expression has a class-wide type, it may still be
9666 -- okay, since it can be the result of the expansion of a call to a
9667 -- dispatching function, so we also have to check class-wideness of the
9668 -- type of the expression's original node.
9671 or else
9675 then
9679 -- If the target type is unconstrained, then we reset the type of the
9680 -- result from the type of the expression. For other cases, the actual
9681 -- subtype of the expression is the target type.
9685 then
9692 -- If we still have a qualified expression after the static evaluation,
9693 -- then apply a scalar range check if needed. The reason that we do this
9694 -- after the Eval call is that otherwise, the application of the range
9695 -- check may convert an illegal static expression and result in warning
9696 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9702 -- Finally, check whether a predicate applies to the target type. This
9703 -- comes from AI12-0100. As for type conversions, check the enclosing
9704 -- context to prevent an infinite expansion.
9710 or else
9712 then
9715 -- In the case of a qualified expression in an allocator, the check
9716 -- is applied when expanding the allocator, so avoid redundant check.
9720 then
9726 ------------------------------
9727 -- Resolve_Raise_Expression --
9728 ------------------------------
9731 begin
9735 else
9740 -------------------
9741 -- Resolve_Range --
9742 -------------------
9749 -- Returns True if N is of the form X'First .. X'Last where X is the
9750 -- same entity for both attributes.
9752 --------------------
9753 -- First_Last_Ref --
9754 --------------------
9760 begin
9765 then
9766 declare
9769 begin
9773 then
9782 -- Start of processing for Resolve_Range
9784 begin
9787 -- The lower bound should be in Typ. The higher bound can be in Typ's
9788 -- base type if the range is null. It may still be invalid if it is
9789 -- higher than the lower bound. This is checked later in the context in
9790 -- which the range appears.
9795 -- Check for inappropriate range on unordered enumeration type
9799 -- Exclude X'First .. X'Last if X is the same entity for both
9801 and then not First_Last_Ref
9802 then
9804 Error_Msg_NE
9811 -- We have to check the bounds for being within the base range as
9812 -- required for a non-static context. Normally this is automatic and
9813 -- done as part of evaluating expressions, but the N_Range node is an
9814 -- exception, since in GNAT we consider this node to be a subexpression,
9815 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9816 -- this, but that would put the test on the main evaluation path for
9817 -- expressions.
9822 -- Check for an ambiguous range over character literals. This will
9823 -- happen with a membership test involving only literals.
9831 -- If bounds are static, constant-fold them, so size computations are
9832 -- identical between front-end and back-end. Do not perform this
9833 -- transformation while analyzing generic units, as type information
9834 -- would be lost when reanalyzing the constant node in the instance.
9847 --------------------------
9848 -- Resolve_Real_Literal --
9849 --------------------------
9854 begin
9855 -- Special processing for fixed-point literals to make sure that the
9856 -- value is an exact multiple of small where this is required. We skip
9857 -- this for the universal real case, and also for generic types.
9863 then
9864 declare
9871 begin
9872 -- Case of literal is not an exact multiple of the Small
9876 -- For a source program literal for a decimal fixed-point type,
9877 -- this is statically illegal (RM 4.9(36)).
9882 then
9886 -- Generate a warning if literal from source
9889 and then Warn_On_Bad_Fixed_Value
9890 then
9891 Error_Msg_N
9893 N);
9896 -- Replace literal by a value that is the exact representation
9897 -- of a value of the type, i.e. a multiple of the small value,
9898 -- by truncation, since Machine_Rounds is false for all GNAT
9899 -- fixed-point types (RM 4.9(38)).
9909 -- In all cases, set the corresponding integer field
9915 -- Now replace the actual type by the expected type as usual
9921 -----------------------
9922 -- Resolve_Reference --
9923 -----------------------
9928 begin
9929 -- Replace general access with specific type
9937 -- If we are taking the reference of a volatile entity, then treat it as
9938 -- a potential modification of this entity. This is too conservative,
9939 -- but necessary because remove side effects can cause transformations
9940 -- of normal assignments into reference sequences that otherwise fail to
9941 -- notice the modification.
9948 --------------------------------
9949 -- Resolve_Selected_Component --
9950 --------------------------------
9965 -- Check whether this is the initialization of a component within an
9966 -- init proc (by assignment or call to another init proc). If true,
9967 -- there is no need for a discriminant check.
9969 --------------------
9970 -- Init_Component --
9971 --------------------
9974 begin
9975 return Inside_Init_Proc
9981 -- Start of processing for Resolve_Selected_Component
9983 begin
9986 -- Use the context type to select the prefix that has a selector
9987 -- of the correct name and type.
9995 else
9999 -- Locate selected component. For a private prefix the selector
10000 -- can denote a discriminant.
10004 -- The visible components of a class-wide type are those of
10005 -- the root type.
10015 then
10022 else
10026 Error_Msg_N
10031 else
10034 -- There may be an implicit dereference. Retrieve
10035 -- designated record type.
10039 else
10045 -- Resolution chooses the new interpretation.
10046 -- Find the component with the right name.
10051 loop
10068 -- There must be a legal interpretation at this point
10075 else
10076 -- Resolve prefix with its type
10081 -- Generate cross-reference. We needed to wait until full overloading
10082 -- resolution was complete to do this, since otherwise we can't tell if
10083 -- we are an lvalue or not.
10087 else
10091 -- If prefix is an access type, the node will be transformed into an
10092 -- explicit dereference during expansion. The type of the node is the
10093 -- designated type of that of the prefix.
10098 else
10102 -- Set flag for expander if discriminant check required on a component
10103 -- appearing within a variant.
10109 and then
10112 and then not Init_Component
10113 then
10121 -- If the prefix is a record conversion, this may be a renamed
10122 -- discriminant whose bounds differ from those of the original
10123 -- one, so we must ensure that a range check is performed.
10128 then
10132 -- Note: No Eval processing is required, because the prefix is of a
10133 -- record type, or protected type, and neither can possibly be static.
10135 -- If the record type is atomic, and the component is non-atomic, then
10136 -- this is worth a warning, since we have a situation where the access
10137 -- to the component may cause extra read/writes of the atomic array
10138 -- object, or partial word accesses, both of which may be unexpected.
10144 then
10145 Error_Msg_N
10148 Error_Msg_N
10156 -------------------
10157 -- Resolve_Shift --
10158 -------------------
10165 begin
10166 -- We do the resolution using the base type, because intermediate values
10167 -- in expressions always are of the base type, not a subtype of it.
10180 ---------------------------
10181 -- Resolve_Short_Circuit --
10182 ---------------------------
10189 begin
10190 -- Ensure all actions associated with the left operand (e.g.
10191 -- finalization of transient objects) are fully evaluated locally within
10192 -- an expression with actions. This is particularly helpful for coverage
10193 -- analysis. However this should not happen in generics or if option
10194 -- Minimize_Expression_With_Actions is set.
10197 declare
10199 begin
10207 -- Set Comes_From_Source on L to preserve warnings for unset
10208 -- reference.
10217 -- Check for issuing warning for always False assert/check, this happens
10218 -- when assertions are turned off, in which case the pragma Assert/Check
10219 -- was transformed into:
10221 -- if False and then <condition> then ...
10223 -- and we detect this pattern
10225 if Warn_On_Assertion_Failure
10232 then
10233 declare
10236 begin
10237 -- Special handling of Asssert pragma
10241 then
10242 declare
10244 Original_Node
10245 (Expression
10248 begin
10249 -- Don't warn if original condition is explicit False,
10250 -- since obviously the failure is expected in this case.
10254 then
10257 -- Issue warning. We do not want the deletion of the
10258 -- IF/AND-THEN to take this message with it. We achieve this
10259 -- by making sure that the expanded code points to the Sloc
10260 -- of the expression, not the original pragma.
10262 else
10263 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10264 -- The source location of the expression is not usually
10265 -- the best choice here. For example, it gets located on
10266 -- the last AND keyword in a chain of boolean expressiond
10267 -- AND'ed together. It is best to put the message on the
10268 -- first character of the assertion, which is the effect
10269 -- of the First_Node call here.
10271 Error_Msg_F
10273 Expression
10278 -- Similar processing for Check pragma
10282 then
10283 -- Don't want to warn if original condition is explicit False
10285 declare
10287 Original_Node
10288 (Expression
10290 begin
10293 then
10296 -- Post warning
10298 else
10299 -- Again use Error_Msg_F rather than Error_Msg_N, see
10300 -- comment above for an explanation of why we do this.
10302 Error_Msg_F
10304 Expression
10312 -- Continue with processing of short circuit
10321 -------------------
10322 -- Resolve_Slice --
10323 -------------------
10332 begin
10335 -- Use the context type to select the prefix that yields the correct
10336 -- array type.
10338 declare
10345 begin
10353 then
10361 else
10366 else
10377 else
10387 -- If the prefix is an access to an unconstrained array, we must use
10388 -- the actual subtype of the object to perform the index checks. The
10389 -- object denoted by the prefix is implicit in the node, so we build
10390 -- an explicit representation for it in order to compute the actual
10391 -- subtype.
10396 declare
10400 begin
10411 then
10414 -- If the name is a selected component that depends on discriminants,
10415 -- build an actual subtype for it. This can happen only when the name
10416 -- itself is overloaded; otherwise the actual subtype is created when
10417 -- the selected component is analyzed.
10420 and then Full_Analysis
10422 then
10423 declare
10426 begin
10431 -- Maybe this should just be "else", instead of checking for the
10432 -- specific case of slice??? This is needed for the case where the
10433 -- prefix is an Image attribute, which gets expanded to a slice, and so
10434 -- has a constrained subtype which we want to use for the slice range
10435 -- check applied below (the range check won't get done if the
10436 -- unconstrained subtype of the 'Image is used).
10442 -- Obtain the type of the array index
10446 else
10450 -- If name was overloaded, set slice type correctly now
10454 -- Handle the generation of a range check that compares the array index
10455 -- against the discrete_range. The check is not applied to internally
10456 -- built nodes associated with the expansion of dispatch tables. Check
10457 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10458 -- the unit.
10460 if Tagged_Type_Expansion
10466 then
10469 -- The discrete_range is specified by a subtype indication. Create a
10470 -- shallow copy and inherit the type, parent and source location from
10471 -- the discrete_range. This ensures that the range check is inserted
10472 -- relative to the slice and that the runtime exception points to the
10473 -- proper construct.
10482 -- The discrete_range is a regular range. Resolve the bounds and remove
10483 -- their side effects.
10485 else
10502 -- Check bad use of type with predicates
10504 declare
10507 begin
10510 then
10512 else
10517 Bad_Predicated_Subtype_Use
10522 -- Otherwise here is where we check suspicious indexes
10533 ----------------------------
10534 -- Resolve_String_Literal --
10535 ----------------------------
10546 begin
10547 -- For a string appearing in a concatenation, defer creation of the
10548 -- string_literal_subtype until the end of the resolution of the
10549 -- concatenation, because the literal may be constant-folded away. This
10550 -- is a useful optimization for long concatenation expressions.
10552 -- If the string is an aggregate built for a single character (which
10553 -- happens in a non-static context) or a is null string to which special
10554 -- checks may apply, we build the subtype. Wide strings must also get a
10555 -- string subtype if they come from a one character aggregate. Strings
10556 -- generated by attributes might be static, but it is often hard to
10557 -- determine whether the enclosing context is static, so we generate
10558 -- subtypes for them as well, thus losing some rarer optimizations ???
10559 -- Same for strings that come from a static conversion.
10561 Need_Check :=
10570 -- If the resolving type is itself a string literal subtype, we can just
10571 -- reuse it, since there is no point in creating another.
10577 and then not Need_Check
10579 N_Attribute_Reference,
10580 N_Qualified_Expression,
10581 N_Type_Conversion)
10582 then
10585 -- Do not generate a string literal subtype for the default expression
10586 -- of a formal parameter in GNATprove mode. This is because the string
10587 -- subtype is associated with the freezing actions of the subprogram,
10588 -- however freezing is disabled in GNATprove mode and as a result the
10589 -- subtype is unavailable.
10591 elsif GNATprove_Mode
10593 then
10596 -- Otherwise we must create a string literal subtype. Note that the
10597 -- whole idea of string literal subtypes is simply to avoid the need
10598 -- for building a full fledged array subtype for each literal.
10600 else
10606 or else Need_Check
10607 then
10614 then
10620 -- The validity of a null string has been checked in the call to
10621 -- Eval_String_Literal.
10626 -- Always accept string literal with component type Any_Character, which
10627 -- occurs in error situations and in comparisons of literals, both of
10628 -- which should accept all literals.
10633 -- If the type is bit-packed, then we always transform the string
10634 -- literal into a full fledged aggregate.
10639 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10641 else
10642 -- For Standard.Wide_Wide_String, or any other type whose component
10643 -- type is Standard.Wide_Wide_Character, we know that all the
10644 -- characters in the string must be acceptable, since the parser
10645 -- accepted the characters as valid character literals.
10650 -- For the case of Standard.String, or any other type whose component
10651 -- type is Standard.Character, we must make sure that there are no
10652 -- wide characters in the string, i.e. that it is entirely composed
10653 -- of characters in range of type Character.
10655 -- If the string literal is the result of a static concatenation, the
10656 -- test has already been performed on the components, and need not be
10657 -- repeated.
10661 then
10665 -- If we are out of range, post error. This is one of the
10666 -- very few places that we place the flag in the middle of
10667 -- a token, right under the offending wide character. Not
10668 -- quite clear if this is right wrt wide character encoding
10669 -- sequences, but it's only an error message.
10671 Error_Msg
10678 -- For the case of Standard.Wide_String, or any other type whose
10679 -- component type is Standard.Wide_Character, we must make sure that
10680 -- there are no wide characters in the string, i.e. that it is
10681 -- entirely composed of characters in range of type Wide_Character.
10683 -- If the string literal is the result of a static concatenation,
10684 -- the test has already been performed on the components, and need
10685 -- not be repeated.
10689 then
10693 -- If we are out of range, post error. This is one of the
10694 -- very few places that we place the flag in the middle of
10695 -- a token, right under the offending wide character.
10697 -- This is not quite right, because characters in general
10698 -- will take more than one character position ???
10700 Error_Msg
10707 -- If the root type is not a standard character, then we will convert
10708 -- the string into an aggregate and will let the aggregate code do
10709 -- the checking. Standard Wide_Wide_Character is also OK here.
10711 else
10715 -- See if the component type of the array corresponding to the string
10716 -- has compile time known bounds. If yes we can directly check
10717 -- whether the evaluation of the string will raise constraint error.
10718 -- Otherwise we need to transform the string literal into the
10719 -- corresponding character aggregate and let the aggregate code do
10720 -- the checking.
10724 -- Check for the case of full range, where we are definitely OK
10730 -- Here the range is not the complete base type range, so check
10732 declare
10740 begin
10743 then
10749 then
10750 Apply_Compile_Time_Constraint_Error
10752 CE_Range_Check_Failed,
10763 -- If we got here we meed to transform the string literal into the
10764 -- equivalent qualified positional array aggregate. This is rather
10765 -- heavy artillery for this situation, but it is hard work to avoid.
10767 declare
10772 begin
10773 -- Build the character literals, we give them source locations that
10774 -- correspond to the string positions, which is a bit tricky given
10775 -- the possible presence of wide character escape sequences.
10789 -- Should we have a call to Skip_Wide here ???
10791 -- ??? else
10792 -- Skip_Wide (P);
10800 Expression =>
10807 -------------------------
10808 -- Resolve_Target_Name --
10809 -------------------------
10812 begin
10816 -----------------------------
10817 -- Resolve_Type_Conversion --
10818 -----------------------------
10830 -- Set to False to suppress cases where we want to suppress the test
10831 -- for redundancy to avoid possible false positives on this warning.
10833 begin
10834 if not Conv_OK
10836 then
10840 -- If the Operand Etype is Universal_Fixed, then the conversion is
10841 -- never redundant. We need this check because by the time we have
10842 -- finished the rather complex transformation, the conversion looks
10843 -- redundant when it is not.
10848 -- If the operand is marked as Any_Fixed, then special processing is
10849 -- required. This is also a case where we suppress the test for a
10850 -- redundant conversion, since most certainly it is not redundant.
10855 -- Mixed-mode operation involving a literal. Context must be a fixed
10856 -- type which is applied to the literal subsequently.
10858 -- Multiplication and division involving two fixed type operands must
10859 -- yield a universal real because the result is computed in arbitrary
10860 -- precision.
10866 then
10872 or else
10874 then
10875 -- Return if expression is ambiguous
10880 -- If nothing else, the available fixed type is Duration
10882 else
10886 -- Resolve the real operand with largest available precision
10890 else
10896 -- If the operand is a literal (it could be a non-static and
10897 -- illegal exponentiation) check whether the use of Duration
10898 -- is potentially inaccurate.
10903 then
10904 Error_Msg_N
10907 Error_Msg_N
10914 then
10917 else
10926 -- In SPARK, a type conversion between array types should be restricted
10927 -- to types which have matching static bounds.
10929 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10930 -- operation if not needed.
10937 then
10938 Check_SPARK_05_Restriction
10942 -- In formal mode, the operand of an ancestor type conversion must be an
10943 -- object (not an expression).
10951 then
10957 -- Note: we do the Eval_Type_Conversion call before applying the
10958 -- required checks for a subtype conversion. This is important, since
10959 -- both are prepared under certain circumstances to change the type
10960 -- conversion to a constraint error node, but in the case of
10961 -- Eval_Type_Conversion this may reflect an illegality in the static
10962 -- case, and we would miss the illegality (getting only a warning
10963 -- message), if we applied the type conversion checks first.
10967 -- Even when evaluation is not possible, we may be able to simplify the
10968 -- conversion or its expression. This needs to be done before applying
10969 -- checks, since otherwise the checks may use the original expression
10970 -- and defeat the simplifications. This is specifically the case for
10971 -- elimination of the floating-point Truncation attribute in
10972 -- float-to-int conversions.
10976 -- If after evaluation we still have a type conversion, then we may need
10977 -- to apply checks required for a subtype conversion.
10979 -- Skip these type conversion checks if universal fixed operands
10980 -- operands involved, since range checks are handled separately for
10981 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10987 then
10991 -- Issue warning for conversion of simple object to its own type. We
10992 -- have to test the original nodes, since they may have been rewritten
10993 -- by various optimizations.
10997 -- Here we test for a redundant conversion if the warning mode is
10998 -- active (and was not locally reset), and we have a type conversion
10999 -- from source not appearing in a generic instance.
11001 if Test_Redundant
11004 and then not In_Instance
11005 then
11009 -- If the node is part of a larger expression, the Target_Type
11010 -- may not be the original type of the node if the context is a
11011 -- condition. Recover original type to see if conversion is needed.
11015 then
11019 -- If we have an entity name, then give the warning if the entity
11020 -- is the right type, or if it is a loop parameter covered by the
11021 -- original type (that's needed because loop parameters have an
11022 -- odd subtype coming from the bounds).
11025 and then
11027 or else
11031 -- If not an entity, then type of expression must match
11034 then
11035 -- One more check, do not give warning if the analyzed conversion
11036 -- has an expression with non-static bounds, and the bounds of the
11037 -- target are static. This avoids junk warnings in cases where the
11038 -- conversion is necessary to establish staticness, for example in
11039 -- a case statement.
11043 then
11046 -- Finally, if this type conversion occurs in a context requiring
11047 -- a prefix, and the expression is a qualified expression then the
11048 -- type conversion is not redundant, since a qualified expression
11049 -- is not a prefix, whereas a type conversion is. For example, "X
11050 -- := T'(Funx(...)).Y;" is illegal because a selected component
11051 -- requires a prefix, but a type conversion makes it legal: "X :=
11052 -- T(T'(Funx(...))).Y;"
11054 -- In Ada 2012, a qualified expression is a name, so this idiom is
11055 -- no longer needed, but we still suppress the warning because it
11056 -- seems unfriendly for warnings to pop up when you switch to the
11057 -- newer language version.
11061 N_Indexed_Component,
11062 N_Selected_Component,
11063 N_Slice,
11064 N_Explicit_Dereference)
11065 then
11068 -- Never warn on conversion to Long_Long_Integer'Base since
11069 -- that is most likely an artifact of the extended overflow
11070 -- checking and comes from complex expanded code.
11075 -- Here we give the redundant conversion warning. If it is an
11076 -- entity, give the name of the entity in the message. If not,
11077 -- just mention the expression.
11079 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11081 else
11084 Error_Msg_NE -- CODEFIX
11087 else
11088 Error_Msg_NE
11096 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11097 -- No need to perform any interface conversion if the type of the
11098 -- expression coincides with the target type.
11101 and then Expander_Active
11103 then
11104 declare
11108 begin
11109 -- If the type of the operand is a limited view, use nonlimited
11110 -- view when available. If it is a class-wide type, recover the
11111 -- class-wide type of the nonlimited view.
11115 then
11131 -- Conversion from interface type
11135 -- Ada 2005 (AI-217): Handle entities from limited views
11139 Error_Msg_NE -- CODEFIX
11142 Error_Msg_N
11144 N);
11147 and then not
11150 then
11152 Error_Msg_NE -- CODEFIX
11155 Error_Msg_N
11157 N);
11159 else
11163 -- Conversion to interface type
11167 -- Handle subtypes
11174 or else Interface_Present_In_Ancestor
11177 then
11179 else
11182 Error_Msg_N
11190 -- Ada 2012: once the type conversion is resolved, check whether the
11191 -- operand statisfies the static predicate of the target type.
11197 -- If at this stage we have a real to integer conversion, make sure that
11198 -- the Do_Range_Check flag is set, because such conversions in general
11199 -- need a range check. We only need this if expansion is off.
11200 -- In GNATprove mode, we only do that when converting from fixed-point
11201 -- (as floating-point to integer conversions are now handled in
11202 -- GNATprove mode).
11205 and then not Expander_Active
11210 then
11214 -- Generating C code a type conversion of an access to constrained
11215 -- array type to access to unconstrained array type involves building
11216 -- a fat pointer which in general cannot be generated on the fly. We
11217 -- remove side effects in order to store the result of the conversion
11218 -- into a temporary.
11220 if Modify_Tree_For_C
11227 then
11232 ----------------------
11233 -- Resolve_Unary_Op --
11234 ----------------------
11243 begin
11246 Check_SPARK_05_Restriction
11250 -- Deal with intrinsic unary operators
11256 then
11261 -- Deal with universal cases
11264 or else
11266 then
11273 -- Generate warning for expressions like abs (x mod 2)
11275 if Warn_On_Redundant_Constructs
11277 then
11281 Error_Msg_N -- CODEFIX
11286 -- Deal with reference generation
11293 -- Set overflow checking bit. Much cleverer code needed here eventually
11294 -- and perhaps the Resolve routines should be separated for the various
11295 -- arithmetic operations, since they will need different processing ???
11303 -- Generate warning for expressions like -5 mod 3 for integers. No need
11304 -- to worry in the floating-point case, since parens do not affect the
11305 -- result so there is no point in giving in a warning.
11307 declare
11316 begin
11317 if Warn_On_Questionable_Missing_Parens
11321 then
11324 -- We are looking for cases where the right operand is not
11325 -- parenthesized, and is a binary operator, multiply, divide, or
11326 -- mod. These are the cases where the grouping can affect results.
11330 then
11331 -- For mod, we always give the warning, since the value is
11332 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11333 -- -(5 mod 315)). But for the other cases, the only concern is
11334 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11335 -- overflows, but (-2) * 64 does not). So we try to give the
11336 -- message only when overflow is possible.
11340 then
11345 else
11351 else
11355 -- Note that the test below is deliberately excluding the
11356 -- largest negative number, since that is a potentially
11357 -- troublesome case (e.g. -2 * x, where the result is the
11358 -- largest negative integer has an overflow with 2 * x).
11365 -- For the multiplication case, the only case we have to worry
11366 -- about is when (-a)*b is exactly the largest negative number
11367 -- so that -(a*b) can cause overflow. This can only happen if
11368 -- a is a power of 2, and more generally if any operand is a
11369 -- constant that is not a power of 2, then the parentheses
11370 -- cannot affect whether overflow occurs. We only bother to
11371 -- test the left most operand
11373 -- Loop looking at left operands for one that has known value
11380 -- Operand value of 0 or 1 skips warning
11385 -- Otherwise check power of 2, if power of 2, warn, if
11386 -- anything else, skip warning.
11388 else
11392 else
11401 -- Keep looking at left operands
11406 -- For rem or "/" we can only have a problematic situation
11407 -- if the divisor has a value of minus one or one. Otherwise
11408 -- overflow is impossible (divisor > 1) or we have a case of
11409 -- division by zero in any case.
11414 then
11418 -- If we fall through warning should be issued
11420 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11422 Error_Msg_N
11429 ----------------------------------
11430 -- Resolve_Unchecked_Expression --
11431 ----------------------------------
11433 procedure Resolve_Unchecked_Expression
11436 is
11437 begin
11442 ---------------------------------------
11443 -- Resolve_Unchecked_Type_Conversion --
11444 ---------------------------------------
11446 procedure Resolve_Unchecked_Type_Conversion
11449 is
11455 begin
11456 -- Resolve operand using its own type
11460 -- In an inlined context, the unchecked conversion may be applied
11461 -- to a literal, in which case its type is the type of the context.
11462 -- (In other contexts conversions cannot apply to literals).
11464 if In_Inlined_Body
11468 then
11476 ------------------------------
11477 -- Rewrite_Operator_As_Call --
11478 ------------------------------
11485 begin
11492 New_N :=
11503 ------------------------------
11504 -- Rewrite_Renamed_Operator --
11505 ------------------------------
11507 procedure Rewrite_Renamed_Operator
11511 is
11516 begin
11517 -- Do not perform this transformation within a pre/postcondition,
11518 -- because the expression will be reanalyzed, and the transformation
11519 -- might affect the visibility of the operator, e.g. in an instance.
11520 -- Note that fully analyzed and expanded pre/postconditions appear as
11521 -- pragma Check equivalents.
11527 -- Likewise when an expression function is being preanalyzed, since the
11528 -- expression will be reanalyzed as part of the generated body.
11531 declare
11533 begin
11536 N_Expression_Function
11537 then
11543 -- Rewrite the operator node using the real operator, not its renaming.
11544 -- Exclude user-defined intrinsic operations of the same name, which are
11545 -- treated separately and rewritten as calls.
11554 -- Indicate that both the original entity and its renaming are
11555 -- referenced at this point.
11566 -- If the context type is private, add the appropriate conversions so
11567 -- that the operator is applied to the full view. This is done in the
11568 -- routines that resolve intrinsic operators.
11572 when N_Op_Add
11573 | N_Op_Divide
11574 | N_Op_Expon
11575 | N_Op_Mod
11576 | N_Op_Multiply
11577 | N_Op_Rem
11578 | N_Op_Subtract
11579 =>
11582 when N_Op_Abs
11583 | N_Op_Minus
11584 | N_Op_Plus
11585 =>
11595 -- Operator renames a user-defined operator of the same name. Use the
11596 -- original operator in the node, which is the one Gigi knows about.
11603 -----------------------
11604 -- Set_Slice_Subtype --
11605 -----------------------
11607 -- Build an implicit subtype declaration to represent the type delivered by
11608 -- the slice. This is an abbreviated version of an array subtype. We define
11609 -- an index subtype for the slice, using either the subtype name or the
11610 -- discrete range of the slice. To be consistent with index usage elsewhere
11611 -- we create a list header to hold the single index. This list is not
11612 -- otherwise attached to the syntax tree.
11623 begin
11629 else
11630 -- We force the evaluation of a range. This is definitely needed in
11631 -- the renamed case, and seems safer to do unconditionally. Note in
11632 -- any case that since we will create and insert an Itype referring
11633 -- to this range, we must make sure any side effect removal actions
11634 -- are inserted before the Itype definition.
11640 -- If the discrete range is given by a subtype indication, the
11641 -- type of the slice is the base of the subtype mark.
11644 declare
11646 begin
11655 -- Take a new copy of Drange (where bounds have been rewritten to
11656 -- reference side-effect-free names). Using a separate tree ensures
11657 -- that further expansion (e.g. while rewriting a slice assignment
11658 -- into a FOR loop) does not attempt to remove side effects on the
11659 -- bounds again (which would cause the bounds in the index subtype
11660 -- definition to refer to temporaries before they are defined) (the
11661 -- reason is that some names are considered side effect free here
11662 -- for the subtype, but not in the context of a loop iteration
11663 -- scheme).
11684 -- The Etype of the existing Slice node is reset to this slice subtype.
11685 -- Its bounds are obtained from its first index.
11689 -- For bit-packed slice subtypes, freeze immediately (except in the case
11690 -- of being in a "spec expression" where we never freeze when we first
11691 -- see the expression).
11696 -- For all other cases insert an itype reference in the slice's actions
11697 -- so that the itype is frozen at the proper place in the tree (i.e. at
11698 -- the point where actions for the slice are analyzed). Note that this
11699 -- is different from freezing the itype immediately, which might be
11700 -- premature (e.g. if the slice is within a transient scope). This needs
11701 -- to be done only if expansion is enabled.
11708 --------------------------------
11709 -- Set_String_Literal_Subtype --
11710 --------------------------------
11718 begin
11730 -- The low bound is set from the low bound of the corresponding index
11731 -- type. Note that we do not store the high bound in the string literal
11732 -- subtype, but it can be deduced if necessary from the length and the
11733 -- low bound.
11738 -- If the lower bound is not static we create a range for the string
11739 -- literal, using the index type and the known length of the literal.
11740 -- The index type is not necessarily Positive, so the upper bound is
11741 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11743 else
11744 declare
11750 Prefix =>
11754 Left_Opnd =>
11757 Prefix =>
11759 Expressions =>
11761 Right_Opnd =>
11770 begin
11772 Set_String_Literal_Low_Bound
11775 else
11776 -- If the index type is an enumeration type, build bounds
11777 -- expression with attributes.
11779 Set_String_Literal_Low_Bound
11783 Prefix =>
11790 -- Build bona fide subtype for the string, and wrap it in an
11791 -- unchecked conversion, because the backend expects the
11792 -- String_Literal_Subtype to have a static lower bound.
11794 Index_Subtype :=
11801 -- In the context, the Index_Type may already have a constraint,
11802 -- so use common base type on string subtype. The base type may
11803 -- be used when generating attributes of the string, for example
11804 -- in the context of a slice assignment.
11829 ------------------------------
11830 -- Simplify_Type_Conversion --
11831 ------------------------------
11834 begin
11836 declare
11841 begin
11842 -- Special processing if the conversion is the expression of a
11843 -- Rounding or Truncation attribute reference. In this case we
11844 -- replace:
11846 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11848 -- by
11850 -- ityp (x)
11852 -- with the Float_Truncate flag set to False or True respectively,
11853 -- which is more efficient.
11856 and then
11862 Name_Truncation)
11863 then
11864 declare
11867 begin
11877 -----------------------------
11878 -- Unique_Fixed_Point_Type --
11879 -----------------------------
11883 -- Give error messages for true ambiguity. Messages are posted on node
11884 -- N, and entities T1, T2 are the possible interpretations.
11886 -----------------------
11887 -- Fixed_Point_Error --
11888 -----------------------
11891 begin
11897 -- Local variables
11905 -- Start of processing for Unique_Fixed_Point_Type
11907 begin
11908 -- The operations on Duration are visible, so Duration is always a
11909 -- possible interpretation.
11913 -- Look for fixed-point types in enclosing scopes
11922 then
11926 else
11937 -- Look for visible fixed type declarations in the context
11948 then
11952 else
11967 else
11968 -- When the context is a type conversion, issue the warning on the
11969 -- expression of the conversion because it is the actual operation.
11973 else
11977 Error_Msg_NE
11984 ----------------------
11985 -- Valid_Conversion --
11986 ----------------------
11988 function Valid_Conversion
11993 is
11998 function Conversion_Check
12001 -- Little routine to post Msg if Valid is False, returns Valid value
12004 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
12006 procedure Conversion_Error_NE
12010 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
12013 -- Return True if expression is within an instance but is not in one of
12014 -- the actuals of the instantiation. Type conversions within an instance
12015 -- are not rechecked because type visbility may lead to spurious errors,
12016 -- but conversions in an actual for a formal object must be checked.
12018 function Valid_Tagged_Conversion
12021 -- Specifically test for validity of tagged conversions
12024 -- Check index and component conformance, and accessibility levels if
12025 -- the component types are anonymous access types (Ada 2005).
12027 ----------------------
12028 -- Conversion_Check --
12029 ----------------------
12031 function Conversion_Check
12034 is
12035 begin
12036 if not Valid
12038 -- A generic unit has already been analyzed and we have verified
12039 -- that a particular conversion is OK in that context. Since the
12040 -- instance is reanalyzed without relying on the relationships
12041 -- established during the analysis of the generic, it is possible
12042 -- to end up with inconsistent views of private types. Do not emit
12043 -- the error message in such cases. The rest of the machinery in
12044 -- Valid_Conversion still ensures the proper compatibility of
12045 -- target and operand types.
12047 and then not In_Instance_Code
12048 then
12055 ------------------------
12056 -- Conversion_Error_N --
12057 ------------------------
12060 begin
12066 -------------------------
12067 -- Conversion_Error_NE --
12068 -------------------------
12070 procedure Conversion_Error_NE
12074 is
12075 begin
12081 ----------------------
12082 -- In_Instance_Code --
12083 ----------------------
12088 begin
12092 else
12096 -- The expression is part of an actual object if it appears in
12097 -- the generated object declaration in the instance.
12101 then
12104 else
12105 exit when
12114 -- Otherwise the expression appears within the instantiated unit
12120 ----------------------------
12121 -- Valid_Array_Conversion --
12122 ----------------------------
12139 begin
12140 -- Error if wrong number of dimensions
12142 if
12144 then
12145 Conversion_Error_N
12149 -- Number of dimensions matches
12151 else
12152 -- Loop through indexes of the two arrays
12160 -- Error if index types are incompatible
12166 then
12167 Conversion_Error_N
12169 Operand);
12177 -- If component types have same base type, all set
12182 -- Here if base types of components are not the same. The only
12183 -- time this is allowed is if we have anonymous access types.
12185 -- The conversion of arrays of anonymous access types can lead
12186 -- to dangling pointers. AI-392 formalizes the accessibility
12187 -- checks that must be applied to such conversions to prevent
12188 -- out-of-scope references.
12190 elsif Ekind_In
12192 E_Anonymous_Access_Subprogram_Type)
12194 and then
12196 then
12199 then
12202 Conversion_Error_N
12212 -- Conversion not allowed because of accessibility levels
12214 else
12215 Conversion_Error_N
12221 else
12225 -- All other cases where component base types do not match
12227 else
12228 Conversion_Error_N
12230 Operand);
12234 -- Check that component subtypes statically match. For numeric
12235 -- types this means that both must be either constrained or
12236 -- unconstrained. For enumeration types the bounds must match.
12237 -- All of this is checked in Subtypes_Statically_Match.
12239 if not Subtypes_Statically_Match
12241 then
12242 Conversion_Error_N
12251 -----------------------------
12252 -- Valid_Tagged_Conversion --
12253 -----------------------------
12255 function Valid_Tagged_Conversion
12258 is
12259 begin
12260 -- Upward conversions are allowed (RM 4.6(22))
12264 then
12267 -- Downward conversion are allowed if the operand is class-wide
12268 -- (RM 4.6(23)).
12272 then
12277 then
12278 return
12282 -- Ada 2005 (AI-251): The conversion to/from interface types is
12283 -- always valid. The types involved may be class-wide (sub)types.
12287 then
12290 -- If the operand is a class-wide type obtained through a limited_
12291 -- with clause, and the context includes the nonlimited view, use
12292 -- it to determine whether the conversion is legal.
12298 then
12303 then
12306 else
12307 Conversion_Error_NE
12314 -- Start of processing for Valid_Conversion
12316 begin
12320 declare
12328 begin
12329 -- Remove procedure calls, which syntactically cannot appear in
12330 -- this context, but which cannot be removed by type checking,
12331 -- because the context does not impose a type.
12333 -- The node may be labelled overloaded, but still contain only one
12334 -- interpretation because others were discarded earlier. If this
12335 -- is the case, retain the single interpretation if legal.
12343 then
12344 -- More than one candidate interpretation is available
12352 -- When compiling for a system where Address is of a visible
12353 -- integer type, spurious ambiguities can be produced when
12354 -- arithmetic operations have a literal operand and return
12355 -- System.Address or a descendant of it. These ambiguities
12356 -- are usually resolved by the context, but for conversions
12357 -- there is no context type and the removal of the spurious
12358 -- operations must be done explicitly here.
12360 if not Address_Is_Private
12362 then
12387 Conversion_Error_N
12390 -- If the interpretation involves a standard operator, use
12391 -- the location of the type, which may be user-defined.
12395 else
12399 Conversion_Error_N -- CODEFIX
12404 else
12408 Conversion_Error_N -- CODEFIX
12420 -- Deal with conversion of integer type to address if the pragma
12421 -- Allow_Integer_Address is in effect. We convert the conversion to
12422 -- an unchecked conversion in this case and we are all done.
12430 -- If we are within a child unit, check whether the type of the
12431 -- expression has an ancestor in a parent unit, in which case it
12432 -- belongs to its derivation class even if the ancestor is private.
12433 -- See RM 7.3.1 (5.2/3).
12437 -- Numeric types
12441 -- A universal fixed expression can be converted to any numeric type
12446 -- Also no need to check when in an instance or inlined body, because
12447 -- the legality has been established when the template was analyzed.
12448 -- Furthermore, numeric conversions may occur where only a private
12449 -- view of the operand type is visible at the instantiation point.
12450 -- This results in a spurious error if we check that the operand type
12451 -- is a numeric type.
12453 -- Note: in a previous version of this unit, the following tests were
12454 -- applied only for generated code (Comes_From_Source set to False),
12455 -- but in fact the test is required for source code as well, since
12456 -- this situation can arise in source code.
12461 -- Otherwise we need the conversion check
12463 else
12464 return Conversion_Check
12466 or else
12472 -- Array types
12478 then
12479 Conversion_Error_N
12483 else
12487 -- Ada 2005 (AI-251): Internally generated conversions of access to
12488 -- interface types added to force the displacement of the pointer to
12489 -- reference the corresponding dispatch table.
12494 then
12497 -- Ada 2005 (AI-251): Anonymous access types where target references an
12498 -- interface type.
12502 E_Anonymous_Access_Type)
12504 then
12505 -- Check the static accessibility rule of 4.6(17). Note that the
12506 -- check is not enforced when within an instance body, since the
12507 -- RM requires such cases to be caught at run time.
12509 -- If the operand is a rewriting of an allocator no check is needed
12510 -- because there are no accessibility issues.
12518 then
12519 -- In an instance, this is a run-time check, but one we know
12520 -- will fail, so generate an appropriate warning. The raise
12521 -- will be generated by Expand_N_Type_Conversion.
12525 Conversion_Error_N
12527 Operand);
12530 else
12531 Conversion_Error_N
12533 Operand);
12537 -- Special accessibility checks are needed in the case of access
12538 -- discriminants declared for a limited type.
12542 then
12543 -- When the operand is a selected access discriminant the check
12544 -- needs to be made against the level of the object denoted by
12545 -- the prefix of the selected name (Object_Access_Level handles
12546 -- checking the prefix of the operand for this case).
12551 then
12552 -- In an instance, this is a run-time check, but one we know
12553 -- will fail, so generate an appropriate warning. The raise
12554 -- will be generated by Expand_N_Type_Conversion.
12558 Conversion_Error_N
12563 -- Real error if not in instance body
12565 else
12566 Conversion_Error_N
12573 -- The case of a reference to an access discriminant from
12574 -- within a limited type declaration (which will appear as
12575 -- a discriminal) is always illegal because the level of the
12576 -- discriminant is considered to be deeper than any (nameable)
12577 -- access type.
12581 and then
12584 then
12585 Conversion_Error_N
12587 Operand);
12595 -- General and anonymous access types
12598 E_Anonymous_Access_Type)
12599 and then
12600 Conversion_Check
12602 and then not
12604 E_Access_Protected_Subprogram_Type),
12606 then
12609 then
12610 Conversion_Error_N
12615 -- Check the static accessibility rule of 4.6(17). Note that the
12616 -- check is not enforced when within an instance body, since the RM
12617 -- requires such cases to be caught at run time.
12622 N_Object_Declaration
12623 then
12624 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12625 -- conversions from an anonymous access type to a named general
12626 -- access type. Such conversions are not allowed in the case of
12627 -- access parameters and stand-alone objects of an anonymous
12628 -- access type. The implicit conversion case is recognized by
12629 -- testing that Comes_From_Source is False and that it's been
12630 -- rewritten. The Comes_From_Source test isn't sufficient because
12631 -- nodes in inlined calls to predefined library routines can have
12632 -- Comes_From_Source set to False. (Is there a better way to test
12633 -- for implicit conversions???)
12640 then
12643 -- Implicit conversions aren't allowed for objects of an
12644 -- anonymous access type, since such objects have nonstatic
12645 -- levels in Ada 2012.
12648 N_Object_Declaration
12649 then
12650 Conversion_Error_N
12655 -- Implicit conversions aren't allowed for anonymous access
12656 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12657 -- is done to exclude anonymous access results.
12661 N_Function_Specification,
12662 N_Procedure_Specification)
12663 then
12664 Conversion_Error_N
12669 -- This is a case where there's an enclosing object whose
12670 -- to which the "statically deeper than" relationship does
12671 -- not apply (such as an access discriminant selected from
12672 -- a dereference of an access parameter).
12676 then
12677 Conversion_Error_N
12682 -- In other cases, the level of the operand's type must be
12683 -- statically less deep than that of the target type, else
12684 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12688 then
12689 Conversion_Error_N
12698 then
12699 -- In an instance, this is a run-time check, but one we know
12700 -- will fail, so generate an appropriate warning. The raise
12701 -- will be generated by Expand_N_Type_Conversion.
12705 Conversion_Error_N
12707 Operand);
12710 -- If not in an instance body, this is a real error
12712 else
12713 -- Avoid generation of spurious error message
12716 Conversion_Error_N
12718 Operand);
12724 -- Special accessibility checks are needed in the case of access
12725 -- discriminants declared for a limited type.
12729 then
12730 -- When the operand is a selected access discriminant the check
12731 -- needs to be made against the level of the object denoted by
12732 -- the prefix of the selected name (Object_Access_Level handles
12733 -- checking the prefix of the operand for this case).
12738 then
12739 -- In an instance, this is a run-time check, but one we know
12740 -- will fail, so generate an appropriate warning. The raise
12741 -- will be generated by Expand_N_Type_Conversion.
12745 Conversion_Error_N
12750 -- If not in an instance body, this is a real error
12752 else
12753 Conversion_Error_N
12760 -- The case of a reference to an access discriminant from
12761 -- within a limited type declaration (which will appear as
12762 -- a discriminal) is always illegal because the level of the
12763 -- discriminant is considered to be deeper than any (nameable)
12764 -- access type.
12767 and then
12770 then
12771 Conversion_Error_N
12773 Operand);
12779 -- In the presence of limited_with clauses we have to use nonlimited
12780 -- views, if available.
12784 -- Helper function to handle limited views
12786 --------------------------
12787 -- Full_Designated_Type --
12788 --------------------------
12793 begin
12794 -- Handle the limited view of a type
12798 then
12800 else
12805 -- Local Declarations
12813 -- Start of processing for Check_Limited
12815 begin
12819 else
12821 Conversion_Error_NE
12826 -- Ada 2005 AI-384: legality rule is symmetric in both
12827 -- designated types. The conversion is legal (with possible
12828 -- constraint check) if either designated type is
12829 -- unconstrained.
12832 or else
12834 and then
12837 then
12838 -- Special case, if Value_Size has been used to make the
12839 -- sizes different, the conversion is not allowed even
12840 -- though the subtypes statically match.
12845 then
12846 Conversion_Error_NE
12849 Conversion_Error_NE
12854 -- Normal case where conversion is allowed
12856 else
12860 else
12861 Error_Msg_NE
12869 -- Access to subprogram types. If the operand is an access parameter,
12870 -- the type has a deeper accessibility that any master, and cannot be
12871 -- assigned. We must make an exception if the conversion is part of an
12872 -- assignment and the target is the return object of an extended return
12873 -- statement, because in that case the accessibility check takes place
12874 -- after the return.
12878 -- Note: this test of Opnd_Type is there to prevent entering this
12879 -- branch in the case of a remote access to subprogram type, which
12880 -- is internally represented as an E_Record_Type.
12883 then
12887 and then
12891 then
12892 Conversion_Error_N
12894 Operand);
12895 Conversion_Error_N
12898 Operand);
12900 Error_Msg_NE
12905 -- Check that the designated types are subtype conformant
12911 -- Check the static accessibility rule of 4.6(20)
12915 then
12916 Conversion_Error_N
12918 Operand);
12920 -- Check that if the operand type is declared in a generic body,
12921 -- then the target type must be declared within that same body
12922 -- (enforces last sentence of 4.6(20)).
12925 declare
12931 begin
12938 Conversion_Error_N
12947 -- Remote access to subprogram types
12951 then
12952 -- It is valid to convert from one RAS type to another provided
12953 -- that their specification statically match.
12955 -- Note: at this point, remote access to subprogram types have been
12956 -- expanded to their E_Record_Type representation, and we need to
12957 -- go back to the original access type definition using the
12958 -- Corresponding_Remote_Type attribute in order to check that the
12959 -- designated profiles match.
12964 Check_Subtype_Conformant
12967 Old_Id =>
12969 Err_Loc =>
12970 N);
12973 -- If it was legal in the generic, it's legal in the instance
12978 -- If both are tagged types, check legality of view conversions
12981 and then
12983 then
12986 -- Types derived from the same root type are convertible
12991 -- In an instance or an inlined body, there may be inconsistent views of
12992 -- the same type, or of types derived from a common root.
12995 and then
12998 then
13001 -- Special check for common access type error case
13005 then
13007 Conversion_Error_NE -- CODEFIX
13011 -- Here we have a real conversion error
13013 else
13014 Conversion_Error_NE