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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) 1992-2014, 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 ------------------------------------------------------------------------------
84 -----------------------
85 -- Local Subprograms --
86 -----------------------
88 -- Second pass (top-down) type checking and overload resolution procedures
89 -- Typ is the type required by context. These procedures propagate the type
90 -- information recursively to the descendants of N. If the node is not
91 -- overloaded, its Etype is established in the first pass. If overloaded,
92 -- the Resolve routines set the correct type. For arith. operators, the
93 -- Etype is the base type of the context.
95 -- Note that Resolve_Attribute is separated off in Sem_Attr
98 -- Enforce the restrictions on the use of discriminants when constraining
99 -- a component of a discriminated type (record or concurrent type).
102 -- Given a node for an operator associated with type T, check that
103 -- the operator is visible. Operators all of whose operands are
104 -- universal must be checked for visibility during resolution
105 -- because their type is not determinable based on their operands.
107 procedure Check_Fully_Declared_Prefix
110 -- Check that the type of the prefix of a dereference is not incomplete
113 -- Given a call node, N, which is known to occur immediately within the
114 -- subprogram being called, determines whether it is a detectable case of
115 -- an infinite recursion, and if so, outputs appropriate messages. Returns
116 -- True if an infinite recursion is detected, and False otherwise.
119 -- If the type of the object being initialized uses the secondary stack
120 -- directly or indirectly, create a transient scope for the call to the
121 -- init proc. This is because we do not create transient scopes for the
122 -- initialization of individual components within the init proc itself.
123 -- Could be optimized away perhaps?
126 -- N is the node for a logical operator. If the operator is predefined, and
127 -- the root type of the operands is Standard.Boolean, then a check is made
128 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
129 -- the style check for Style_Check_Boolean_And_Or.
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.
203 function Operator_Kind
206 -- Utility to map the name of an operator into the corresponding Node. Used
207 -- by other node rewriting procedures.
210 -- Resolve actuals of call, and add default expressions for missing ones.
211 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
212 -- called subprogram.
215 -- Called from Resolve_Call, when the prefix denotes an entry or element
216 -- of entry family. Actuals are resolved as for subprograms, and the node
217 -- is rebuilt as an entry call. Also called for protected operations. Typ
218 -- is the context type, which is used when the operation is a protected
219 -- function with no arguments, and the return value is indexed.
222 -- A call to a user-defined intrinsic operator is rewritten as a call to
223 -- the corresponding predefined operator, with suitable conversions. Note
224 -- that this applies only for intrinsic operators that denote predefined
225 -- operators, not ones that are intrinsic imports of back-end builtins.
228 -- Ditto, for arithmetic unary operators
231 -- If an operator node resolves to a call to a user-defined operator,
232 -- rewrite the node as a function call.
234 procedure Make_Call_Into_Operator
238 -- Inverse transformation: if an operator is given in functional notation,
239 -- then after resolving the node, transform into an operator node, so
240 -- that operands are resolved properly. Recall that predefined operators
241 -- do not have a full signature and special resolution rules apply.
243 procedure Rewrite_Renamed_Operator
247 -- An operator can rename another, e.g. in an instantiation. In that
248 -- case, the proper operator node must be constructed and resolved.
251 -- The String_Literal_Subtype is built for all strings that are not
252 -- operands of a static concatenation operation. If the argument is
253 -- not a N_String_Literal node, then the call has no effect.
256 -- Build subtype of array type, with the range specified by the slice
259 -- Called after N has been resolved and evaluated, but before range checks
260 -- have been applied. Currently simplifies a combination of floating-point
261 -- to integer conversion and Rounding or Truncation attribute.
264 -- A universal_fixed expression in an universal context is unambiguous if
265 -- there is only one applicable fixed point type. Determining whether there
266 -- is only one requires a search over all visible entities, and happens
267 -- only in very pathological cases (see 6115-006).
269 -------------------------
270 -- Ambiguous_Character --
271 -------------------------
276 begin
280 -- First the ones in Standard
285 -- Include Wide_Wide_Character in Ada 2005 mode
291 -- Now any other types that match
301 -------------------------
302 -- Analyze_And_Resolve --
303 -------------------------
306 begin
312 begin
317 -- Versions with check(s) suppressed
319 procedure Analyze_And_Resolve
323 is
326 begin
328 declare
330 begin
336 else
337 declare
339 begin
347 and then Scope_Is_Transient
348 then
349 -- This can only happen if a transient scope was created for an inner
350 -- expression, which will be removed upon completion of the analysis
351 -- of an enclosing construct. The transient scope must have the
352 -- suppress status of the enclosing environment, not of this Analyze
353 -- call.
356 Scope_Suppress;
360 procedure Analyze_And_Resolve
363 is
366 begin
368 declare
370 begin
376 else
377 declare
379 begin
388 Scope_Suppress;
392 ----------------------------
393 -- Check_Discriminant_Use --
394 ----------------------------
402 begin
403 -- Any use in a spec-expression is legal
410 -- Discriminant cannot be used to constrain a scalar type
417 then
422 -- The following check catches the unusual case where a
423 -- discriminant appears within an index constraint that is part of
424 -- a larger expression within a constraint on a component, e.g. "C
425 -- : Int range 1 .. F (new A(1 .. D))". For now we only check case
426 -- of record components, and note that a similar check should also
427 -- apply in the case of discriminant constraints below. ???
429 -- Note that the check for N_Subtype_Declaration below is to
430 -- detect the valid use of discriminants in the constraints of a
431 -- subtype declaration when this subtype declaration appears
432 -- inside the scope of a record type (which is syntactically
433 -- illegal, but which may be created as part of derived type
434 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
435 -- for more info.
439 and then not
441 and then
443 N_Subtype_Declaration)
445 then
446 Error_Msg_N
451 -- Detect a common error:
453 -- type R (D : Positive := 100) is record
454 -- Name : String (1 .. D);
455 -- end record;
457 -- The default value causes an object of type R to be allocated
458 -- with room for Positive'Last characters. The RM does not mandate
459 -- the allocation of the maximum size, but that is what GNAT does
460 -- so we should warn the programmer that there is a problem.
469 -- Return True if type T has a large enough range that any
470 -- array whose index type covered the whole range of the type
471 -- would likely raise Storage_Error.
473 ------------------------
474 -- Large_Storage_Type --
475 ------------------------
478 begin
479 -- The type is considered large if its bounds are known at
480 -- compile time and if it requires at least as many bits as
481 -- a Positive to store the possible values.
485 and then
490 -- Start of processing for Check_Large
492 begin
493 -- Check that the Disc has a large range
499 -- If the enclosing type is limited, we allocate only the
500 -- default value, not the maximum, and there is no need for
501 -- a warning.
507 -- Check that it is the high bound
511 then
515 -- Check the array allows a large range at this bound. First
516 -- find the array
530 -- Next, find the dimension
538 loop
547 -- Now, check the dimension has a large range
553 -- Warn about the danger
555 Error_Msg_N
565 -- Legal case is in index or discriminant constraint
568 N_Discriminant_Association)
569 then
571 Error_Msg_N
576 then
577 Error_Msg_N
583 -- Otherwise, context is an expression. It should not be within (i.e. a
584 -- subexpression of) a constraint for a component.
586 else
590 N_Subtype_Indication,
591 N_Entry_Declaration)
592 loop
598 -- If the discriminant is used in an expression that is a bound of a
599 -- scalar type, an Itype is created and the bounds are attached to
600 -- its range, not to the original subtype indication. Such use is of
601 -- course a double fault.
605 N_Derived_Type_Definition)
608 -- The constraint itself may be given by a subtype indication,
609 -- rather than by a more common discrete range.
612 and then
616 then
617 Error_Msg_N
623 --------------------------------
624 -- Check_For_Visible_Operator --
625 --------------------------------
628 begin
630 Error_Msg_NE -- CODEFIX
632 Error_Msg_N -- CODEFIX
637 ----------------------------------
638 -- Check_Fully_Declared_Prefix --
639 ----------------------------------
641 procedure Check_Fully_Declared_Prefix
644 is
645 begin
646 -- Check that the designated type of the prefix of a dereference is
647 -- not an incomplete type. This cannot be done unconditionally, because
648 -- dereferences of private types are legal in default expressions. This
649 -- case is taken care of in Check_Fully_Declared, called below. There
650 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
652 -- This consideration also applies to similar checks for allocators,
653 -- qualified expressions, and type conversions.
655 -- An additional exception concerns other per-object expressions that
656 -- are not directly related to component declarations, in particular
657 -- representation pragmas for tasks. These will be per-object
658 -- expressions if they depend on discriminants or some global entity.
659 -- If the task has access discriminants, the designated type may be
660 -- incomplete at the point the expression is resolved. This resolution
661 -- takes place within the body of the initialization procedure, where
662 -- the discriminant is replaced by its discriminal.
666 then
669 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
670 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
671 -- Analyze_Object_Renaming, and Freeze_Entity.
677 E_Incomplete_Type
679 then
681 else
686 ------------------------------
687 -- Check_Infinite_Recursion --
688 ------------------------------
695 -- Check whether list of actuals is identical to list of formals of
696 -- called function (which is also the enclosing scope).
698 ------------------------
699 -- Same_Argument_List --
700 ------------------------
707 begin
710 else
719 then
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_Initialization_Call --
856 -------------------------------
862 -- Check whether the creation of an object of the type will involve
863 -- use of the secondary stack. If T is a record type, this is true
864 -- if the expression for some component uses the secondary stack, e.g.
865 -- through a call to a function that returns an unconstrained value.
866 -- False if T is controlled, because cleanups occur elsewhere.
868 -------------
869 -- Uses_SS --
870 -------------
877 begin
878 -- Normally we want to use the underlying type, but if it's not set
879 -- then continue with T.
896 then
897 -- The expression for a dynamic component may be rewritten
898 -- as a dereference, so retrieve original node.
902 -- Return True if the expression is a call to a function
903 -- (including an attribute function such as Image, or a
904 -- user-defined operator) with a result that requires a
905 -- transient scope.
912 then
925 else
930 -- Start of processing for Check_Initialization_Call
932 begin
933 -- Establish a transient scope if the type needs it
940 ---------------------------------------
941 -- Check_No_Direct_Boolean_Operators --
942 ---------------------------------------
945 begin
948 then
949 -- Restriction only applies to original source code
956 -- Do style check (but skip if in instance, error is on template)
965 ------------------------------
966 -- Check_Parameterless_Call --
967 ------------------------------
973 -- If the prefix is of an access_to_subprogram type, the node must be
974 -- rewritten as a call. Ditto if the prefix is overloaded and all its
975 -- interpretations are access to subprograms.
977 ---------------------------
978 -- Prefix_Is_Access_Subp --
979 ---------------------------
985 begin
986 -- If the context is an attribute reference that can apply to
987 -- functions, this is never a parameterless call (RM 4.1.4(6)).
991 Name_Code_Address,
992 Name_Access)
993 then
998 return
1001 else
1006 then
1017 -- Start of processing for Check_Parameterless_Call
1019 begin
1020 -- Defend against junk stuff if errors already detected
1027 then
1034 -- If the context expects a value, and the name is a procedure, this is
1035 -- most likely a missing 'Access. Don't try to resolve the parameterless
1036 -- call, error will be caught when the outer call is analyzed.
1041 and then
1043 N_Function_Call,
1044 N_Procedure_Call_Statement)
1045 then
1049 -- Rewrite as call if overloadable entity that is (or could be, in the
1050 -- overloaded case) a function call. If we know for sure that the entity
1051 -- is an enumeration literal, we do not rewrite it.
1053 -- If the entity is the name of an operator, it cannot be a call because
1054 -- operators cannot have default parameters. In this case, this must be
1055 -- a string whose contents coincide with an operator name. Set the kind
1056 -- of the node appropriately.
1064 -- Rewrite as call if it is an explicit dereference of an expression of
1065 -- a subprogram access type, and the subprogram type is not that of a
1066 -- procedure or entry.
1068 or else
1071 -- Rewrite as call if it is a selected component which is a function,
1072 -- this is the case of a call to a protected function (which may be
1073 -- overloaded with other protected operations).
1075 or else
1078 or else
1080 E_Procedure)
1083 -- If one of the above three conditions is met, rewrite as call. Apply
1084 -- the rewriting only once.
1086 then
1089 then
1091 -- This may be a prefixed call that was not fully analyzed, e.g.
1092 -- an actual in an instance.
1097 then
1105 -- The node is the name of the parameterless call. Preserve its
1106 -- descendants, which may be complex expressions.
1110 -- If overloaded, overload set belongs to new copy
1114 -- Change node to parameterless function call (note that the
1115 -- Parameter_Associations associations field is left set to Empty,
1116 -- its normal default value since there are no parameters)
1134 -----------------------------
1135 -- Is_Definite_Access_Type --
1136 -----------------------------
1140 begin
1146 ----------------------
1147 -- Is_Predefined_Op --
1148 ----------------------
1151 begin
1152 -- Predefined operators are intrinsic subprograms
1158 -- A call to a back-end builtin is never a predefined operator
1169 -----------------------------
1170 -- Make_Call_Into_Operator --
1171 -----------------------------
1173 procedure Make_Call_Into_Operator
1177 is
1192 -- If the operand is not universal, and the operator is given by an
1193 -- expanded name, verify that the operand has an interpretation with a
1194 -- type defined in the given scope of the operator.
1197 -- Find a type of the given class in package Pack that contains the
1198 -- operator.
1200 ---------------------------
1201 -- Operand_Type_In_Scope --
1202 ---------------------------
1209 begin
1213 else
1227 ---------------
1228 -- Type_In_P --
1229 ---------------
1235 -- Verify that node is not part of the type declaration for the
1236 -- candidate type, which would otherwise be invisible.
1238 -------------
1239 -- In_Decl --
1240 -------------
1246 begin
1255 else
1258 loop
1261 else
1270 -- Start of processing for Type_In_P
1272 begin
1273 -- If the context type is declared in the prefix package, this is the
1274 -- desired base type.
1279 else
1283 and then not In_Decl
1284 then
1295 -- Start of processing for Make_Call_Into_Operator
1297 begin
1300 -- Binary operator
1310 -- Unary operator
1312 else
1318 -- If the operator is denoted by an expanded name, and the prefix is
1319 -- not Standard, but the operator is a predefined one whose scope is
1320 -- Standard, then this is an implicit_operator, inserted as an
1321 -- interpretation by the procedure of the same name. This procedure
1322 -- overestimates the presence of implicit operators, because it does
1323 -- not examine the type of the operands. Verify now that the operand
1324 -- type appears in the given scope. If right operand is universal,
1325 -- check the other operand. In the case of concatenation, either
1326 -- argument can be the component type, so check the type of the result.
1327 -- If both arguments are literals, look for a type of the right kind
1328 -- defined in the given scope. This elaborate nonsense is brought to
1329 -- you courtesy of b33302a. The type itself must be frozen, so we must
1330 -- find the type of the proper class in the given scope.
1332 -- A final wrinkle is the multiplication operator for fixed point types,
1333 -- which is defined in Standard only, and not in the scope of the
1334 -- fixed point type itself.
1339 -- If this is a package renaming, get renamed entity, which will be
1340 -- the scope of the operands if operaton is type-correct.
1346 -- If the entity being called is defined in the given package, it is
1347 -- a renaming of a predefined operator, and known to be legal.
1351 then
1354 -- Visibility does not need to be checked in an instance: if the
1355 -- operator was not visible in the generic it has been diagnosed
1356 -- already, else there is an implicit copy of it in the instance.
1364 then
1369 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1370 -- available.
1375 then
1378 else
1387 and then Is_Binary
1389 then
1395 -- Verify that the scope contains a type that corresponds to
1396 -- the given literal. Optimize the case where Pack is Standard.
1418 else
1427 else
1436 then
1439 -- If the type is defined elsewhere, and the operator is not
1440 -- defined in the given scope (by a renaming declaration, e.g.)
1441 -- then this is an error as well. If an extension of System is
1442 -- present, and the type may be defined there, Pack must be
1443 -- System itself.
1450 then
1453 else
1459 then
1466 Error_Msg_NE
1471 -- Detect a mismatch between the context type and the result type
1472 -- in the named package, which is otherwise not detected if the
1473 -- operands are universal. Check is only needed if source entity is
1474 -- an operator, not a function that renames an operator.
1481 and then not In_Instance
1482 then
1485 then
1486 -- Already checked above
1490 -- Operator may be defined in an extension of System
1494 then
1497 else
1498 -- Could we use Wrong_Type here??? (this would require setting
1499 -- Etype (N) to the actual type found where Typ was expected).
1510 else
1514 -- If this is a call to a function that renames a predefined equality,
1515 -- the renaming declaration provides a type that must be used to
1516 -- resolve the operands. This must be done now because resolution of
1517 -- the equality node will not resolve any remaining ambiguity, and it
1518 -- assumes that the first operand is not overloaded.
1523 then
1531 -- Do rewrite setting Comes_From_Source on the result if the original
1532 -- call came from source. Although it is not strictly the case that the
1533 -- operator as such comes from the source, logically it corresponds
1534 -- exactly to the function call in the source, so it should be marked
1535 -- this way (e.g. to make sure that validity checks work fine).
1537 declare
1539 begin
1544 -- If this is an arithmetic operator and the result type is private,
1545 -- the operands and the result must be wrapped in conversion to
1546 -- expose the underlying numeric type and expand the proper checks,
1547 -- e.g. on division.
1551 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1552 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1561 else
1565 -- If in ASIS_Mode, propagate operand types to original actuals of
1566 -- function call, which would otherwise not be fully resolved. If
1567 -- the call has already been constant-folded, nothing to do. We
1568 -- relocate the operand nodes rather than copy them, to preserve
1569 -- original_node pointers, given that the operands themselves may
1570 -- have been rewritten. If the call was itself a rewriting of an
1571 -- operator node, nothing to do.
1573 if ASIS_Mode
1576 then
1582 else
1591 -------------------
1592 -- Operator_Kind --
1593 -------------------
1595 function Operator_Kind
1598 is
1601 begin
1602 -- Use CASE statement or array???
1639 else
1643 -- Unary operators
1645 else
1654 else
1662 ----------------------------
1663 -- Preanalyze_And_Resolve --
1664 ----------------------------
1669 begin
1673 -- Normally, we suppress all checks for this preanalysis. There is no
1674 -- point in processing them now, since they will be applied properly
1675 -- and in the proper location when the default expressions reanalyzed
1676 -- and reexpanded later on. We will also have more information at that
1677 -- point for possible suppression of individual checks.
1679 -- However, in SPARK mode, most expansion is suppressed, and this
1680 -- later reanalysis and reexpansion may not occur. SPARK mode does
1681 -- require the setting of checking flags for proof purposes, so we
1682 -- do the SPARK preanalysis without suppressing checks.
1684 -- This special handling for SPARK mode is required for example in the
1685 -- case of Ada 2012 constructs such as quantified expressions, which are
1686 -- expanded in two separate steps.
1690 else
1694 Expander_Mode_Restore;
1698 -- Version without context type
1703 begin
1710 Expander_Mode_Restore;
1714 ----------------------------------
1715 -- Replace_Actual_Discriminants --
1716 ----------------------------------
1723 -- Comment needed???
1725 -------------------
1726 -- Process_Discr --
1727 -------------------
1732 begin
1738 then
1754 -- Start of processing for Replace_Actual_Discriminants
1756 begin
1770 else
1775 -------------
1776 -- Resolve --
1777 -------------
1793 -- Determine whether a node comes from a predefined library unit or
1794 -- Standard.
1797 -- Try and fix up a literal so that it matches its expected type. New
1798 -- literals are manufactured if necessary to avoid cascaded errors.
1801 -- Additional diagnostics when an ambiguous call has an ambiguous
1802 -- argument (typically a controlling actual).
1805 -- Called when attempt at resolving current expression fails
1807 ------------------------------------
1808 -- Comes_From_Predefined_Lib_Unit --
1809 -------------------------------------
1812 begin
1813 return
1815 or else Is_Predefined_File_Name
1819 --------------------
1820 -- Patch_Up_Value --
1821 --------------------
1824 begin
1841 then
1846 Char_Literal_Value =>
1862 -------------------------------
1863 -- Report_Ambiguous_Argument --
1864 -------------------------------
1871 begin
1875 then
1878 -- Could use comments on what is going on here???
1886 else
1895 -----------------------
1896 -- Resolution_Failed --
1897 -----------------------
1900 begin
1906 -- The caller will return without calling the expander, so we need
1907 -- to set the analyzed flag. Note that it is fine to set Analyzed
1908 -- to True even if we are in the middle of a shallow analysis,
1909 -- (see the spec of sem for more details) since this is an error
1910 -- situation anyway, and there is no point in repeating the
1911 -- analysis later (indeed it won't work to repeat it later, since
1912 -- we haven't got a clear resolution of which entity is being
1913 -- referenced.)
1919 -- Start of processing for Resolve
1921 begin
1926 -- Access attribute on remote subprogram cannot be used for a non-remote
1927 -- access-to-subprogram type.
1931 Name_Unrestricted_Access,
1932 Name_Unchecked_Access)
1938 then
1939 Error_Msg_N
1945 -- If the context is a Remote_Access_To_Subprogram, access attributes
1946 -- must be resolved with the corresponding fat pointer. There is no need
1947 -- to check for the attribute name since the return type of an
1948 -- attribute is never a remote type.
1953 then
1954 declare
1962 begin
1963 -- Check that Typ is a remote access-to-subprogram type
1967 -- Prefix (N) must statically denote a remote subprogram
1968 -- declared in a package specification.
1972 Attr = Attribute_Unrestricted_Access
1973 then
1988 or else
1990 then
1992 Error_Msg_N
1994 N);
1997 -- If we are generating code in distributed mode, perform
1998 -- semantic checks against corresponding remote entities.
2000 if Expander_Active
2002 then
2003 Check_Subtype_Conformant
2005 Old_Id => Designated_Type
2031 then
2036 -- Return if already analyzed
2043 -- Any case of Any_Type as the Etype value means that we had a
2044 -- previous error.
2053 -- The resolution of an Expression_With_Actions is determined by
2054 -- its Expression.
2062 -- If not overloaded, then we know the type, and all that needs doing
2063 -- is to check that this type is compatible with the context.
2069 -- In the overloaded case, we must select the interpretation that
2070 -- is compatible with the context (i.e. the type passed to Resolve)
2072 else
2073 -- Loop through possible interpretations
2083 -- We are only interested in interpretations that are compatible
2084 -- with the expected type, any other interpretations are ignored.
2089 Write_Eol;
2092 else
2093 -- Skip the current interpretation if it is disabled by an
2094 -- abstract operator. This action is performed only when the
2095 -- type against which we are resolving is the same as the
2096 -- type of the interpretation.
2103 then
2111 -- First matching interpretation
2119 -- Matching interpretation that is not the first, maybe an
2120 -- error, but there are some cases where preference rules are
2121 -- used to choose between the two possibilities. These and
2122 -- some more obscure cases are handled in Disambiguate.
2124 else
2125 -- If the current statement is part of a predefined library
2126 -- unit, then all interpretations which come from user level
2127 -- packages should not be considered. Check previous and
2128 -- current one.
2136 -- Previous interpretation must be discarded
2146 -- Otherwise apply further disambiguation steps
2151 -- Disambiguation has succeeded. Skip the remaining
2152 -- interpretations.
2162 else
2163 -- Before we issue an ambiguity complaint, check for
2164 -- the case of a subprogram call where at least one
2165 -- of the arguments is Any_Type, and if so, suppress
2166 -- the message, since it is a cascaded error.
2169 declare
2173 begin
2185 Write_Eol;
2198 then
2203 then
2207 -- Not that special case, so issue message using the
2208 -- flag Ambiguous to control printing of the header
2209 -- message only at the start of an ambiguous set.
2214 then
2215 Error_Msg_N
2218 else
2219 Error_Msg_NE -- CODEFIX
2227 Error_Msg_N
2229 else
2230 Error_Msg_N -- CODEFIX
2236 then
2237 Report_Ambiguous_Argument;
2243 -- By default, the error message refers to the candidate
2244 -- interpretation. But if it is a predefined operator, it
2245 -- is implicitly declared at the declaration of the type
2246 -- of the operand. Recover the sloc of that declaration
2247 -- for the error message.
2253 Standard_Standard
2254 then
2259 then
2267 Standard_Standard
2268 then
2273 then
2277 -- If this is an indirect call, use the subprogram_type
2278 -- in the message, to have a meaningful location. Also
2279 -- indicate if this is an inherited operation, created
2280 -- by a type declaration.
2285 then
2287 Error_Msg_Sloc :=
2289 else
2296 then
2297 -- Special-case the message for universal_fixed
2298 -- operators, which are not declared with the type
2299 -- of the operand, but appear forever in Standard.
2303 then
2304 Error_Msg_N
2307 else
2308 Error_Msg_N
2312 elsif
2314 then
2315 Error_Msg_N
2317 else
2318 Error_Msg_N -- CODEFIX
2325 -- We have a matching interpretation, Expr_Type is the type
2326 -- from this interpretation, and Seen is the entity.
2328 -- For an operator, just set the entity name. The type will be
2329 -- set by the specific operator resolution routine.
2344 -- AI05-0139-2: Expression is overloaded because type has
2345 -- implicit dereference. If type matches context, no implicit
2346 -- dereference is involved.
2357 then
2358 -- If the node is a general indexing, the dereference is
2359 -- is inserted when resolving the rewritten form, else
2360 -- insert it now.
2364 then
2368 -- For an explicit dereference, attribute reference, range,
2369 -- short-circuit form (which is not an operator node), or call
2370 -- with a name that is an explicit dereference, there is
2371 -- nothing to be done at this point.
2374 N_Attribute_Reference,
2375 N_And_Then,
2376 N_Indexed_Component,
2377 N_Or_Else,
2378 N_Range,
2379 N_Selected_Component,
2380 N_Slice)
2382 then
2385 -- For procedure or function calls, set the type of the name,
2386 -- and also the entity pointer for the prefix.
2390 then
2397 then
2402 -- For all other cases, just set the type of the Name
2404 else
2412 -- Move to next interpretation
2420 -- At this stage Found indicates whether or not an acceptable
2421 -- interpretation exists. If not, then we have an error, except that if
2422 -- the context is Any_Type as a result of some other error, then we
2423 -- suppress the error report.
2428 -- If type we are looking for is Void, then this is the procedure
2429 -- call case, and the error is simply that what we gave is not a
2430 -- procedure name (we think of procedure calls as expressions with
2431 -- types internally, but the user doesn't think of them this way).
2435 -- Special case message if function used as a procedure
2440 then
2441 Error_Msg_NE
2445 -- Otherwise give general message (not clear what cases this
2446 -- covers, but no harm in providing for them).
2448 else
2454 -- Otherwise we do have a subexpression with the wrong type
2456 -- Check for the case of an allocator which uses an access type
2457 -- instead of the designated type. This is a common error and we
2458 -- specialize the message, posting an error on the operand of the
2459 -- allocator, complaining that we expected the designated type of
2460 -- the allocator.
2466 then
2470 -- Check for view mismatch on Null in instances, for which the
2471 -- view-swapping mechanism has no identifier.
2477 then
2482 -- Check for an aggregate. Sometimes we can get bogus aggregates
2483 -- from misuse of parentheses, and we are about to complain about
2484 -- the aggregate without even looking inside it.
2486 -- Instead, if we have an aggregate of type Any_Composite, then
2487 -- analyze and resolve the component fields, and then only issue
2488 -- another message if we get no errors doing this (otherwise
2489 -- assume that the errors in the aggregate caused the problem).
2493 then
2494 -- Disable expansion in any case. If there is a type mismatch
2495 -- it may be fatal to try to expand the aggregate. The flag
2496 -- would otherwise be set to false when the error is posted.
2500 declare
2502 -- Check one aggregate, and set Found to True if we have a
2503 -- definite error in any of its elements
2506 -- Check one element of aggregate and set Found to True if
2507 -- we definitely have an error in the element.
2509 ----------------
2510 -- Check_Aggr --
2511 ----------------
2516 begin
2529 -- If this is a default-initialized component, then
2530 -- there is nothing to check. The box will be
2531 -- replaced by the appropriate call during late
2532 -- expansion.
2543 ----------------
2544 -- Check_Elmt --
2545 ----------------
2548 begin
2549 -- If we have a nested aggregate, go inside it (to
2550 -- attempt a naked analyze-resolve of the aggregate can
2551 -- cause undesirable cascaded errors). Do not resolve
2552 -- expression if it needs a type from context, as for
2553 -- integer * fixed expression.
2558 else
2563 then
2573 begin
2578 -- Looks like we have a type error, but check for special case
2579 -- of Address wanted, integer found, with the configuration pragma
2580 -- Allow_Integer_Address active. If we have this case, introduce
2581 -- an unchecked conversion to allow the integer expression to be
2582 -- treated as an Address. The reverse case of integer wanted,
2583 -- Address found, is treated in an analogous manner.
2591 -- That special Allow_Integer_Address check did not appply, so we
2592 -- have a real type error. If an error message was issued already,
2593 -- Found got reset to True, so if it's still False, issue standard
2594 -- Wrong_Type message.
2598 declare
2601 begin
2607 -- Protected operation: retrieve operation name
2611 else
2616 Error_Msg_NE
2622 declare
2626 begin
2633 Error_Msg_NE
2639 else
2643 else
2649 Resolution_Failed;
2652 -- Test if we have more than one interpretation for the context
2655 Resolution_Failed;
2658 -- Only one intepretation
2660 else
2661 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2662 -- the "+" on T is abstract, and the operands are of universal type,
2663 -- the above code will have (incorrectly) resolved the "+" to the
2664 -- universal one in Standard. Therefore check for this case and give
2665 -- an error. We can't do this earlier, because it would cause legal
2666 -- cases to get errors (when some other type has an abstract "+").
2672 then
2677 then
2678 Error_Msg_NE
2687 -- Here we have an acceptable interpretation for the context
2689 -- Propagate type information and normalize tree for various
2690 -- predefined operations. If the context only imposes a class of
2691 -- types, rather than a specific type, propagate the actual type
2692 -- downward.
2698 Typ = Any_Discrete
2699 then
2702 -- Any_Fixed is legal in a real context only if a specific fixed-
2703 -- point type is imposed. If Norman Cohen can be confused by this,
2704 -- it deserves a separate message.
2708 then
2715 -- A user-defined operator is transformed into a function call at
2716 -- this point, so that further processing knows that operators are
2717 -- really operators (i.e. are predefined operators). User-defined
2718 -- operators that are intrinsic are just renamings of the predefined
2719 -- ones, and need not be turned into calls either, but if they rename
2720 -- a different operator, we must transform the node accordingly.
2721 -- Instantiations of Unchecked_Conversion are intrinsic but are
2722 -- treated as functions, even if given an operator designator.
2727 then
2733 and then
2735 N_Subprogram_Renaming_Declaration
2736 then
2739 -- If the node is rewritten, it will be fully resolved in
2740 -- Rewrite_Renamed_Operator.
2750 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2752 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2754 when N_Short_Circuit
2755 => Resolve_Short_Circuit (N, Ctx_Type);
2757 when N_Attribute_Reference
2758 => Resolve_Attribute (N, Ctx_Type);
2760 when N_Case_Expression
2761 => Resolve_Case_Expression (N, Ctx_Type);
2763 when N_Character_Literal
2764 => Resolve_Character_Literal (N, Ctx_Type);
2766 when N_Expanded_Name
2767 => Resolve_Entity_Name (N, Ctx_Type);
2769 when N_Explicit_Dereference
2770 => Resolve_Explicit_Dereference (N, Ctx_Type);
2772 when N_Expression_With_Actions
2773 => Resolve_Expression_With_Actions (N, Ctx_Type);
2775 when N_Extension_Aggregate
2776 => Resolve_Extension_Aggregate (N, Ctx_Type);
2778 when N_Function_Call
2779 => Resolve_Call (N, Ctx_Type);
2781 when N_Identifier
2782 => Resolve_Entity_Name (N, Ctx_Type);
2784 when N_If_Expression
2785 => Resolve_If_Expression (N, Ctx_Type);
2787 when N_Indexed_Component
2788 => Resolve_Indexed_Component (N, Ctx_Type);
2790 when N_Integer_Literal
2791 => Resolve_Integer_Literal (N, Ctx_Type);
2793 when N_Membership_Test
2794 => Resolve_Membership_Op (N, Ctx_Type);
2796 when N_Null => Resolve_Null (N, Ctx_Type);
2798 when N_Op_And | N_Op_Or | N_Op_Xor
2799 => Resolve_Logical_Op (N, Ctx_Type);
2801 when N_Op_Eq | N_Op_Ne
2802 => Resolve_Equality_Op (N, Ctx_Type);
2804 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2805 => Resolve_Comparison_Op (N, Ctx_Type);
2807 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2809 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2810 N_Op_Divide | N_Op_Mod | N_Op_Rem
2812 => Resolve_Arithmetic_Op (N, Ctx_Type);
2814 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2816 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2818 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2819 => Resolve_Unary_Op (N, Ctx_Type);
2821 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2823 when N_Procedure_Call_Statement
2824 => Resolve_Call (N, Ctx_Type);
2826 when N_Operator_Symbol
2827 => Resolve_Operator_Symbol (N, Ctx_Type);
2829 when N_Qualified_Expression
2830 => Resolve_Qualified_Expression (N, Ctx_Type);
2832 -- Why is the following null, needs a comment ???
2834 when N_Quantified_Expression
2835 => null;
2837 when N_Raise_Expression
2838 => Resolve_Raise_Expression (N, Ctx_Type);
2840 when N_Raise_xxx_Error
2841 => Set_Etype (N, Ctx_Type);
2843 when N_Range => Resolve_Range (N, Ctx_Type);
2845 when N_Real_Literal
2846 => Resolve_Real_Literal (N, Ctx_Type);
2848 when N_Reference => Resolve_Reference (N, Ctx_Type);
2850 when N_Selected_Component
2851 => Resolve_Selected_Component (N, Ctx_Type);
2853 when N_Slice => Resolve_Slice (N, Ctx_Type);
2855 when N_String_Literal
2856 => Resolve_String_Literal (N, Ctx_Type);
2858 when N_Type_Conversion
2859 => Resolve_Type_Conversion (N, Ctx_Type);
2861 when N_Unchecked_Expression =>
2862 Resolve_Unchecked_Expression (N, Ctx_Type);
2864 when N_Unchecked_Type_Conversion =>
2865 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2866 end case;
2868 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2869 -- expression of an anonymous access type that occurs in the context
2870 -- of a named general access type, except when the expression is that
2871 -- of a membership test. This ensures proper legality checking in
2872 -- terms of allowed conversions (expressions that would be illegal to
2873 -- convert implicitly are allowed in membership tests).
2875 if Ada_Version >= Ada_2012
2876 and then Ekind (Ctx_Type) = E_General_Access_Type
2877 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2878 and then Nkind (Parent (N)) not in N_Membership_Test
2879 then
2880 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2881 Analyze_And_Resolve (N, Ctx_Type);
2882 end if;
2884 -- If the subexpression was replaced by a non-subexpression, then
2885 -- all we do is to expand it. The only legitimate case we know of
2886 -- is converting procedure call statement to entry call statements,
2887 -- but there may be others, so we are making this test general.
2889 if Nkind (N) not in N_Subexpr then
2890 Debug_A_Exit ("resolving ", N, " (done)");
2891 Expand (N);
2892 return;
2893 end if;
2895 -- The expression is definitely NOT overloaded at this point, so
2896 -- we reset the Is_Overloaded flag to avoid any confusion when
2897 -- reanalyzing the node.
2899 Set_Is_Overloaded (N, False);
2901 -- Freeze expression type, entity if it is a name, and designated
2902 -- type if it is an allocator (RM 13.14(10,11,13)).
2904 -- Now that the resolution of the type of the node is complete, and
2905 -- we did not detect an error, we can expand this node. We skip the
2906 -- expand call if we are in a default expression, see section
2907 -- "Handling of Default Expressions" in Sem spec.
2909 Debug_A_Exit ("resolving ", N, " (done)");
2911 -- We unconditionally freeze the expression, even if we are in
2912 -- default expression mode (the Freeze_Expression routine tests this
2913 -- flag and only freezes static types if it is set).
2915 -- Ada 2012 (AI05-177): The declaration of an expression function
2916 -- does not cause freezing, but we never reach here in that case.
2917 -- Here we are resolving the corresponding expanded body, so we do
2918 -- need to perform normal freezing.
2920 Freeze_Expression (N);
2922 -- Now we can do the expansion
2924 Expand (N);
2925 end if;
2926 end Resolve;
2928 -------------
2929 -- Resolve --
2930 -------------
2932 -- Version with check(s) suppressed
2934 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2935 begin
2936 if Suppress = All_Checks then
2937 declare
2938 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
2939 begin
2940 Scope_Suppress.Suppress := (others => True);
2941 Resolve (N, Typ);
2942 Scope_Suppress.Suppress := Sva;
2943 end;
2945 else
2946 declare
2947 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
2948 begin
2949 Scope_Suppress.Suppress (Suppress) := True;
2950 Resolve (N, Typ);
2951 Scope_Suppress.Suppress (Suppress) := Svg;
2952 end;
2953 end if;
2954 end Resolve;
2956 -------------
2957 -- Resolve --
2958 -------------
2960 -- Version with implicit type
2962 procedure Resolve (N : Node_Id) is
2963 begin
2964 Resolve (N, Etype (N));
2965 end Resolve;
2967 ---------------------
2968 -- Resolve_Actuals --
2969 ---------------------
2971 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2972 Loc : constant Source_Ptr := Sloc (N);
2973 A : Node_Id;
2974 A_Id : Entity_Id;
2975 A_Typ : Entity_Id;
2976 F : Entity_Id;
2977 F_Typ : Entity_Id;
2978 Prev : Node_Id := Empty;
2979 Orig_A : Node_Id;
2981 procedure Check_Aliased_Parameter;
2982 -- Check rules on aliased parameters and related accessibility rules
2983 -- in (RM 3.10.2 (10.2-10.4)).
2985 procedure Check_Argument_Order;
2986 -- Performs a check for the case where the actuals are all simple
2987 -- identifiers that correspond to the formal names, but in the wrong
2988 -- order, which is considered suspicious and cause for a warning.
2990 procedure Check_Prefixed_Call;
2991 -- If the original node is an overloaded call in prefix notation,
2993 -- Try_Object_Operation has already verified that there is a valid
2994 -- interpretation, but the form of the actual can only be determined
2995 -- once the primitive operation is identified.
2998 -- If the actual is missing in a call, insert in the actuals list
2999 -- an instance of the default expression. The insertion is always
3000 -- a named association.
3002 procedure Property_Error
3006 -- Emit an error concerning variable Var with entity Var_Id that has
3007 -- enabled property Prop_Nam when it acts as an actual parameter in a
3008 -- call and the corresponding formal parameter is of mode IN.
3011 -- Check whether T1 and T2, or their full views, are derived from a
3012 -- common type. Used to enforce the restrictions on array conversions
3013 -- of AI95-00246.
3016 -- Predicate to determine whether an actual that is a concatenation
3017 -- will be evaluated statically and does not need a transient scope.
3018 -- This must be determined before the actual is resolved and expanded
3019 -- because if needed the transient scope must be introduced earlier.
3021 ------------------------------
3022 -- Check_Aliased_Parameter --
3023 ------------------------------
3028 begin
3036 else
3043 -- In a generic body assume the worst for generic formals:
3044 -- they can have a constrained partial view (AI05-041).
3050 then
3053 else
3058 else
3070 then
3078 then
3079 Error_Msg_N
3085 --------------------------
3086 -- Check_Argument_Order --
3087 --------------------------
3090 begin
3091 -- Nothing to do if no parameters, or original node is neither a
3092 -- function call nor a procedure call statement (happens in the
3093 -- operator-transformed-to-function call case), or the call does
3094 -- not come from source, or this warning is off.
3096 if not Warn_On_Parameter_Order
3100 then
3104 declare
3107 begin
3108 -- Nothing to do if only one parameter
3114 -- Here if at least two arguments
3116 declare
3122 -- Set True if an out of order case is found
3124 begin
3125 -- Collect identifier names of actuals, fail if any actual is
3126 -- not a simple identifier, and record max length of name.
3132 else
3138 -- If we got this far, all actuals are identifiers and the list
3139 -- of their names is stored in the Actuals array.
3144 -- If we ran out of formals, that's odd, probably an error
3145 -- which will be detected elsewhere, but abandon the search.
3151 -- If name matches and is in order OK
3156 else
3157 -- If no match, see if it is elsewhere in list and if so
3158 -- flag potential wrong order if type is compatible.
3162 and then
3164 then
3170 -- No match
3178 -- If Formals left over, also probably an error, skip warning
3184 -- Here we give the warning if something was out of order
3187 Error_Msg_N
3194 -------------------------
3195 -- Check_Prefixed_Call --
3196 -------------------------
3205 begin
3206 -- Check whether the call is a prefixed call, with or without
3207 -- additional actuals.
3210 or else
3216 then
3219 then
3220 -- Introduce dereference on object in prefix
3222 New_A :=
3230 then
3231 -- Introduce an implicit 'Access in prefix
3234 Error_Msg_NE
3250 --------------------
3251 -- Insert_Default --
3252 --------------------
3258 begin
3259 -- Missing argument in call, nothing to insert
3264 else
3265 -- Note that we do a full New_Copy_Tree, so that any associated
3266 -- Itypes are properly copied. This may not be needed any more,
3267 -- but it does no harm as a safety measure. Defaults of a generic
3268 -- formal may be out of bounds of the corresponding actual (see
3269 -- cc1311b) and an additional check may be required.
3271 Actval :=
3272 New_Copy_Tree
3279 then
3285 then
3288 then
3289 -- If default is a real literal, do not introduce a
3290 -- conversion whose effect may depend on the run-time
3291 -- size of universal real.
3295 else
3306 -- Resolve aggregates with their base type, to avoid scope
3307 -- anomalies: the subtype was first built in the subprogram
3308 -- declaration, and the current call may be nested.
3312 else
3316 else
3319 -- See note above concerning aggregates
3323 then
3326 -- Resolve entities with their own type, which may differ from
3327 -- the type of a reference in a generic context (the view
3328 -- swapping mechanism did not anticipate the re-analysis of
3329 -- default values in calls).
3334 else
3339 -- If default is a tag indeterminate function call, propagate tag
3340 -- to obtain proper dispatching.
3344 then
3350 -- If the default expression raises constraint error, then just
3351 -- silently replace it with an N_Raise_Constraint_Error node, since
3352 -- we already gave the warning on the subprogram spec. If node is
3353 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3354 -- the warnings removal machinery.
3358 then
3366 Assoc :=
3371 -- Case of insertion is first named actual
3375 then
3382 else
3386 else
3390 -- Case of insertion is not first named actual
3392 else
3393 Set_Next_Named_Actual
3405 --------------------
3406 -- Property_Error --
3407 --------------------
3409 procedure Property_Error
3413 is
3414 begin
3416 Error_Msg_NE
3422 -------------------
3423 -- Same_Ancestor --
3424 -------------------
3430 begin
3433 then
3439 then
3446 --------------------------
3447 -- Static_Concatenation --
3448 --------------------------
3451 begin
3458 -- Concatenation is static when both operands are static and
3459 -- the concatenation operator is a predefined one.
3462 and then
3464 and then
3469 declare
3471 begin
3474 and then
3478 else
3484 -- Start of processing for Resolve_Actuals
3486 begin
3487 Check_Argument_Order;
3491 Check_Prefixed_Call;
3500 -- If we have an error in any actual or formal, indicated by a type
3501 -- of Any_Type, then abandon resolution attempt, and set result type
3502 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3503 -- type is imposed from context.
3507 then
3514 -- Case where actual is present
3516 -- If the actual is an entity, generate a reference to it now. We
3517 -- do this before the actual is resolved, because a formal of some
3518 -- protected subprogram, or a task discriminant, will be rewritten
3519 -- during expansion, and the source entity reference may be lost.
3524 then
3530 then
3537 -- RM 6.4.1(12): For an out parameter that is passed by
3538 -- copy, the formal parameter object is created, and:
3540 -- * For an access type, the formal parameter is initialized
3541 -- from the value of the actual, without checking that the
3542 -- value satisfies any constraint, any predicate, or any
3543 -- exclusion of the null value.
3545 -- * For a scalar type that has the Default_Value aspect
3546 -- specified, the formal parameter is initialized from the
3547 -- value of the actual, without checking that the value
3548 -- satisfies any constraint or any predicate.
3549 -- I do not understand why this case is included??? this is
3550 -- not a case where an OUT parameter is treated as IN OUT.
3552 -- * For a composite type with discriminants or that has
3553 -- implicit initial values for any subcomponents, the
3554 -- behavior is as for an in out parameter passed by copy.
3556 -- Hence for these cases we generate the read reference now
3557 -- (the write reference will be generated later by
3558 -- Note_Possible_Modification).
3561 and then
3563 or else
3565 and then
3567 or else
3570 or else Is_Partially_Initialized_Type
3572 then
3582 then
3583 -- If style checking mode on, check match of formal name
3591 -- If the formal is Out or In_Out, do not resolve and expand the
3592 -- conversion, because it is subsequently expanded into explicit
3593 -- temporaries and assignments. However, the object of the
3594 -- conversion can be resolved. An exception is the case of tagged
3595 -- type conversion with a class-wide actual. In that case we want
3596 -- the tag check to occur and no temporary will be needed (no
3597 -- representation change can occur) and the parameter is passed by
3598 -- reference, so we go ahead and resolve the type conversion.
3599 -- Another exception is the case of reference to component or
3600 -- subcomponent of a bit-packed array, in which case we want to
3601 -- defer expansion to the point the in and out assignments are
3602 -- performed.
3607 then
3610 then
3611 -- In a view conversion, the conversion must be legal in
3612 -- both directions, and thus both component types must be
3613 -- aliased, or neither (4.6 (8)).
3615 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3616 -- the privacy requirement should not apply to generic
3617 -- types, and should be checked in an instance. ARG query
3618 -- is in order ???
3622 then
3623 Error_Msg_N
3627 -- Comment here??? what set of cases???
3629 elsif
3631 then
3632 -- Check view conv between unrelated by ref array types
3636 then
3637 Error_Msg_N
3641 -- In Ada 2005 mode, check view conversion component
3642 -- type cannot be private, tagged, or volatile. Note
3643 -- that we only apply this to source conversions. The
3644 -- generated code can contain conversions which are
3645 -- not subject to this test, and we cannot extract the
3646 -- component type in such cases since it is not present.
3650 then
3651 declare
3653 Component_Type
3655 begin
3660 then
3661 Error_Msg_N
3672 -- Resolve expression if conversion is all OK
3677 then
3681 -- If the actual is a function call that returns a limited
3682 -- unconstrained object that needs finalization, create a
3683 -- transient scope for it, so that it can receive the proper
3684 -- finalization list.
3689 and then Expander_Active
3691 then
3695 -- A small optimization: if one of the actuals is a concatenation
3696 -- create a block around a procedure call to recover stack space.
3697 -- This alleviates stack usage when several procedure calls in
3698 -- the same statement list use concatenation. We do not perform
3699 -- this wrapping for code statements, where the argument is a
3700 -- static string, and we want to preserve warnings involving
3701 -- sequences of such statements.
3705 and then Expander_Active
3706 and then
3710 then
3714 else
3718 and then
3721 then
3722 Error_Msg_N
3735 -- (Ada 2005: AI-251): If the actual is an allocator whose
3736 -- directly designated type is a class-wide interface, we build
3737 -- an anonymous access type to use it as the type of the
3738 -- allocator. Later, when the subprogram call is expanded, if
3739 -- the interface has a secondary dispatch table the expander
3740 -- will add a type conversion to force the correct displacement
3741 -- of the pointer.
3744 declare
3750 begin
3753 then
3756 Set_Directly_Designated_Type
3761 -- Ada 2005, AI-162:If the actual is an allocator, the
3762 -- innermost enclosing statement is the master of the
3763 -- created object. This needs to be done with expansion
3764 -- enabled only, otherwise the transient scope will not
3765 -- be removed in the expansion of the wrapped construct.
3768 and then Expander_Active
3769 then
3779 -- (Ada 2005): The call may be to a primitive operation of a
3780 -- tagged synchronized type, declared outside of the type. In
3781 -- this case the controlling actual must be converted to its
3782 -- corresponding record type, which is the formal type. The
3783 -- actual may be a subtype, either because of a constraint or
3784 -- because it is a generic actual, so use base type to locate
3785 -- concurrent type.
3792 then
3793 -- If the actual is overloaded, look for an interpretation
3794 -- that has a synchronized type.
3799 else
3800 declare
3804 begin
3809 then
3819 declare
3822 begin
3825 else
3829 -- Tagged synchronized type (case 1): the actual is a
3830 -- concurrent type.
3834 then
3836 Unchecked_Convert_To
3840 -- Tagged synchronized type (case 2): the formal is a
3841 -- concurrent type.
3844 and then Present
3849 then
3852 -- Common case
3854 else
3859 -- Not a synchronized operation
3861 else
3869 -- An actual cannot be an untagged formal incomplete type
3874 then
3875 Error_Msg_N
3881 N_Procedure_Call_Statement)
3882 then
3883 -- In formal mode, check that actual parameters matching
3884 -- formals of tagged types are objects (or ancestor type
3885 -- conversions of objects), not general expressions.
3892 declare
3897 begin
3899 Check_SPARK_Restriction
3902 -- In formal mode, the only view conversions are those
3903 -- involving ancestor conversion of an extended type.
3905 elsif not
3911 then
3912 if Ekind_In
3914 then
3915 Check_SPARK_Restriction
3918 else
3919 Check_SPARK_Restriction
3923 else
3928 else
3932 -- In formal mode, the only view conversions are those
3933 -- involving ancestor conversion of an extended type.
3937 then
3938 Check_SPARK_Restriction
3944 -- has warnings suppressed, then we reset Never_Set_In_Source for
3945 -- the calling entity. The reason for this is to catch cases like
3946 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3947 -- uses trickery to modify an IN parameter.
3954 then
3958 -- Perform error checks for IN and IN OUT parameters
3962 -- Check unset reference. For scalar parameters, it is clearly
3963 -- wrong to pass an uninitialized value as either an IN or
3964 -- IN-OUT parameter. For composites, it is also clearly an
3965 -- error to pass a completely uninitialized value as an IN
3966 -- parameter, but the case of IN OUT is trickier. We prefer
3967 -- not to give a warning here. For example, suppose there is
3968 -- a routine that sets some component of a record to False.
3969 -- It is perfectly reasonable to make this IN-OUT and allow
3970 -- either initialized or uninitialized records to be passed
3971 -- in this case.
3973 -- For partially initialized composite values, we also avoid
3974 -- warnings, since it is quite likely that we are passing a
3975 -- partially initialized value and only the initialized fields
3976 -- will in fact be read in the subprogram.
3981 then
3985 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3986 -- actual to a nested call, since this is case of reading an
3987 -- out parameter, which is not allowed.
3992 then
3997 -- Case of OUT or IN OUT parameter
4001 -- For an Out parameter, check for useless assignment. Note
4002 -- that we can't set Last_Assignment this early, because we may
4003 -- kill current values in Resolve_Call, and that call would
4004 -- clobber the Last_Assignment field.
4006 -- Note: call Warn_On_Useless_Assignment before doing the check
4007 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4008 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4009 -- reflects the last assignment, not this one.
4016 then
4021 -- Validate the form of the actual. Note that the call to
4022 -- Is_OK_Variable_For_Out_Formal generates the required
4023 -- reference in this case.
4025 -- A call to an initialization procedure for an aggregate
4026 -- component may initialize a nested component of a constant
4027 -- designated object. In this context the object is variable.
4031 then
4035 and then
4038 then
4039 Error_Msg_N
4045 -- What's the following about???
4049 else
4050 Kill_All_Checks;
4059 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4063 -- Apply predicate tests except in certain special cases. Note
4064 -- that it might be more consistent to apply these only when
4065 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4066 -- for the outbound predicate tests ???
4072 -- Apply required constraint checks
4074 -- Gigi looks at the check flag and uses the appropriate types.
4075 -- For now since one flag is used there is an optimization
4076 -- which might not be done in the IN OUT case since Gigi does
4077 -- not do any analysis. More thought required about this ???
4079 -- In fact is this comment obsolete??? doesn't the expander now
4080 -- generate all these tests anyway???
4093 then
4096 -- For view conversions of a discriminated object, apply
4097 -- check to object itself, the conversion alreay has the
4098 -- proper type.
4102 then
4109 then
4115 then
4118 else
4122 -- Ada 2005 (AI-231): Note that the controlling parameter case
4123 -- already existed in Ada 95, which is partially checked
4124 -- elsewhere (see Checks), and we don't want the warning
4125 -- message to differ.
4130 then
4132 Apply_Compile_Time_Constraint_Error
4138 Apply_Compile_Time_Constraint_Error
4147 -- Checks for OUT parameters and IN OUT parameters
4151 -- If there is a type conversion, to make sure the return value
4152 -- meets the constraints of the variable before the conversion.
4156 Apply_Scalar_Range_Check
4158 else
4159 Apply_Range_Check
4163 -- If no conversion apply scalar range checks and length checks
4164 -- base on the subtype of the actual (NOT that of the formal).
4166 else
4171 then
4173 else
4178 -- Note: we do not apply the predicate checks for the case of
4179 -- OUT and IN OUT parameters. They are instead applied in the
4180 -- Expand_Actuals routine in Exp_Ch6.
4183 -- An actual associated with an access parameter is implicitly
4184 -- converted to the anonymous access type of the formal and must
4185 -- satisfy the legality checks for access conversions.
4189 Error_Msg_N
4193 -- If the actual is an access selected component of a variable,
4194 -- the call may modify its designated object. It is reasonable
4195 -- to treat this as a potential modification of the enclosing
4196 -- record, to prevent spurious warnings that it should be
4197 -- declared as a constant, because intuitively programmers
4198 -- regard the designated subcomponent as part of the record.
4203 then
4208 -- Check bad case of atomic/volatile argument (RM C.6(12))
4212 then
4215 then
4216 Error_Msg_NE
4222 then
4223 Error_Msg_NE
4229 -- Check that subprograms don't have improper controlling
4230 -- arguments (RM 3.9.2 (9)).
4232 -- A primitive operation may have an access parameter of an
4233 -- incomplete tagged type, but a dispatching call is illegal
4234 -- if the type is still incomplete.
4240 declare
4242 begin
4246 then
4247 Error_Msg_NE
4261 then
4266 then
4268 Error_Msg_NE
4272 -- Apply the checks described in 3.10.2(27): if the context is a
4273 -- specific access-to-object, the actual cannot be class-wide.
4274 -- Use base type to exclude access_to_subprogram cases.
4281 and then
4286 -- Disable these checks for call to imported C++ subprograms
4288 and then not
4292 then
4293 Error_Msg_N
4298 Error_Msg_NE
4303 Check_Aliased_Parameter;
4307 -- If it is a named association, treat the selector_name as a
4308 -- proper identifier, and mark the corresponding entity.
4312 -- Ignore reference in SPARK mode, as it refers to an entity not
4313 -- in scope at the point of reference, so the reference should
4314 -- be ignored for computing effects of subprograms.
4316 and then not GNATprove_Mode
4317 then
4330 -- The following checks are only relevant when SPARK_Mode is on as
4331 -- they are not standard Ada legality rule. Internally generated
4332 -- temporaries are ignored.
4337 then
4338 -- An effectively volatile object may act as an actual
4339 -- parameter when the corresponding formal is of a non-scalar
4340 -- volatile type.
4344 then
4347 -- An effectively volatile object may act as an actual
4348 -- parameter in a call to an instance of Unchecked_Conversion.
4353 else
4354 Error_Msg_N
4359 -- Detect an external variable with an enabled property that
4360 -- does not match the mode of the corresponding formal in a
4361 -- procedure call. Functions are not considered because they
4362 -- cannot have effectively volatile formal parameters in the
4363 -- first place.
4369 then
4383 then
4385 Error_Msg_NE
4389 Error_Msg_N
4397 -- Case where actual is not present
4399 else
4400 Insert_Default;
4407 -----------------------
4408 -- Resolve_Allocator --
4409 -----------------------
4421 procedure Check_Allocator_Discrim_Accessibility
4424 -- Check that accessibility level associated with an access discriminant
4425 -- initialized in an allocator by the expression Disc_Exp is not deeper
4426 -- than the level of the allocator type Alloc_Typ. An error message is
4427 -- issued if this condition is violated. Specialized checks are done for
4428 -- the cases of a constraint expression which is an access attribute or
4429 -- an access discriminant.
4432 -- If the allocator is an actual in a call, it is allowed to be class-
4433 -- wide when the context is not because it is a controlling actual.
4435 -------------------------------------------
4436 -- Check_Allocator_Discrim_Accessibility --
4437 -------------------------------------------
4439 procedure Check_Allocator_Discrim_Accessibility
4442 is
4443 begin
4446 then
4447 Error_Msg_N
4450 -- When the expression is an Access attribute the level of the prefix
4451 -- object must not be deeper than that of the allocator's type.
4455 Attribute_Access
4458 then
4459 Error_Msg_N
4461 Disc_Exp);
4463 -- When the expression is an access discriminant the check is against
4464 -- the level of the prefix object.
4470 then
4471 Error_Msg_N
4473 Disc_Exp);
4475 -- All other cases are legal
4477 else
4482 ----------------------------
4483 -- In_Dispatching_Context --
4484 ----------------------------
4489 begin
4495 -- Start of processing for Resolve_Allocator
4497 begin
4498 -- Replace general access with specific type
4508 -- For qualified expression, resolve the expression using the given
4509 -- subtype (nothing to do for type mark, subtype indication)
4514 and then not In_Dispatching_Context
4515 then
4516 Error_Msg_N
4524 -- A qualified expression requires an exact match of the type.
4525 -- Class-wide matching is not allowed.
4530 then
4534 -- Calls to build-in-place functions are not currently supported in
4535 -- allocators for access types associated with a simple storage pool.
4536 -- Supporting such allocators may require passing additional implicit
4537 -- parameters to build-in-place functions (or a significant revision
4538 -- of the current b-i-p implementation to unify the handling for
4539 -- multiple kinds of storage pools). ???
4543 then
4544 declare
4547 begin
4549 and then
4550 Present (Get_Rep_Pragma
4552 then
4553 Error_Msg_N
4560 -- A special accessibility check is needed for allocators that
4561 -- constrain access discriminants. The level of the type of the
4562 -- expression used to constrain an access discriminant cannot be
4563 -- deeper than the type of the allocator (in contrast to access
4564 -- parameters, where the level of the actual can be arbitrary).
4566 -- We can't use Valid_Conversion to perform this check because in
4567 -- general the type of the allocator is unrelated to the type of
4568 -- the access discriminant.
4572 then
4579 then
4582 -- Get the first component expression of the aggregate
4592 else
4596 else
4615 else
4620 else
4629 -- For a subtype mark or subtype indication, freeze the subtype
4631 else
4635 Error_Msg_N
4639 -- A special accessibility check is needed for allocators that
4640 -- constrain access discriminants. The level of the type of the
4641 -- expression used to constrain an access discriminant cannot be
4642 -- deeper than the type of the allocator (in contrast to access
4643 -- parameters, where the level of the actual can be arbitrary).
4644 -- We can't use Valid_Conversion to perform this check because
4645 -- in general the type of the allocator is unrelated to the type
4646 -- of the access discriminant.
4651 then
4661 else
4675 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4676 -- check that the level of the type of the created object is not deeper
4677 -- than the level of the allocator's access type, since extensions can
4678 -- now occur at deeper levels than their ancestor types. This is a
4679 -- static accessibility level check; a run-time check is also needed in
4680 -- the case of an initialized allocator with a class-wide argument (see
4681 -- Expand_Allocator_Expression).
4685 then
4686 declare
4689 begin
4694 else
4700 then
4703 Error_Msg_N
4712 -- Do not apply Ada 2005 accessibility checks on a class-wide
4713 -- allocator if the type given in the allocator is a formal
4714 -- type. A run-time check will be performed in the instance.
4724 -- Check for allocation from an empty storage pool
4729 -- If the context is an unchecked conversion, as may happen within an
4730 -- inlined subprogram, the allocator is being resolved with its own
4731 -- anonymous type. In that case, if the target type has a specific
4732 -- storage pool, it must be inherited explicitly by the allocator type.
4736 then
4737 Set_Associated_Storage_Pool
4745 -- Check that an allocator with task parts isn't for a nested access
4746 -- type when restriction No_Task_Hierarchy applies.
4750 then
4754 -- An illegal allocator may be rewritten as a raise Program_Error
4755 -- statement.
4759 -- An anonymous access discriminant is the definition of a
4760 -- coextension.
4764 N_Discriminant_Specification
4765 then
4766 declare
4770 begin
4773 -- Ada 2012 AI05-0052: If the designated type of the allocator
4774 -- is limited, then the allocator shall not be used to define
4775 -- the value of an access discriminant unless the discriminated
4776 -- type is immutably limited.
4781 then
4782 Error_Msg_N
4788 -- Avoid marking an allocator as a dynamic coextension if it is
4789 -- within a static construct.
4795 -- Cleanup for potential static coextensions
4797 else
4803 -- Report a simple error: if the designated object is a local task,
4804 -- its body has not been seen yet, and its activation will fail an
4805 -- elaboration check.
4812 then
4818 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4819 -- type with a task component on a subpool. This action must raise
4820 -- Program_Error at runtime.
4826 then
4838 ---------------------------
4839 -- Resolve_Arithmetic_Op --
4840 ---------------------------
4842 -- Used for resolving all arithmetic operators except exponentiation
4853 -- We do the resolution using the base type, because intermediate values
4854 -- in expressions always are of the base type, not a subtype of it.
4857 -- Returns True if N is in a context that expects "any real type"
4860 -- Return True iff given type is Integer or universal real/integer
4863 -- Choose type of integer literal in fixed-point operation to conform
4864 -- to available fixed-point type. T is the type of the other operand,
4865 -- which is needed to determine the expected type of N.
4868 -- Set operand type to T if universal
4870 -------------------------------
4871 -- Expected_Type_Is_Any_Real --
4872 -------------------------------
4875 begin
4876 -- N is the expression after "delta" in a fixed_point_definition;
4877 -- see RM-3.5.9(6):
4880 N_Decimal_Fixed_Point_Definition,
4882 -- N is one of the bounds in a real_range_specification;
4883 -- see RM-3.5.7(5):
4885 N_Real_Range_Specification,
4887 -- N is the expression of a delta_constraint;
4888 -- see RM-J.3(3):
4890 N_Delta_Constraint);
4893 -----------------------------
4894 -- Is_Integer_Or_Universal --
4895 -----------------------------
4902 begin
4908 else
4914 then
4925 ----------------------------
4926 -- Set_Mixed_Mode_Operand --
4927 ----------------------------
4933 begin
4936 -- A universal integer literal is resolved as standard integer
4937 -- except in the case of a fixed-point result, where we leave it
4938 -- as universal (to be handled by Exp_Fixd later on)
4942 else
4950 then
4951 -- A universal real can appear in a fixed-type context. We resolve
4952 -- the literal with that context, even though this might raise an
4953 -- exception prematurely (the other operand may be zero).
4960 then
4961 -- Integer arg in mixed-mode operation. Resolve with universal
4962 -- type, in case preference rule must be applied.
4968 then
4969 -- Not a mixed-mode operation, resolve with context
4975 -- N may itself be a mixed-mode operation, so use context type
4982 then
4983 -- Must be (fixed * fixed) operation, operand must have one
4984 -- compatible interpretation.
4991 then
4992 -- C * F(X) in a fixed context, where C is a real literal or a
4993 -- fixed-point expression. F must have either a fixed type
4994 -- interpretation or an integer interpretation, but not both.
5001 else
5008 else
5016 -- Reanalyze the literal with the fixed type of the context. If
5017 -- context is Universal_Fixed, we are within a conversion, leave
5018 -- the literal as a universal real because there is no usable
5019 -- fixed type, and the target of the conversion plays no role in
5020 -- the resolution.
5022 declare
5026 begin
5029 else
5035 then
5037 else
5045 else
5050 ----------------------
5051 -- Set_Operand_Type --
5052 ----------------------
5055 begin
5058 then
5063 -- Start of processing for Resolve_Arithmetic_Op
5065 begin
5070 then
5074 -- Special-case for mixed-mode universal expressions or fixed point type
5075 -- operation: each argument is resolved separately. The same treatment
5076 -- is required if one of the operands of a fixed point operation is
5077 -- universal real, since in this case we don't do a conversion to a
5078 -- specific fixed-point type (instead the expander handles the case).
5080 -- Set the type of the node to its universal interpretation because
5081 -- legality checks on an exponentiation operand need the context.
5086 then
5097 or else
5100 then
5105 -- If context is a fixed type and one operand is integer, the other
5106 -- is resolved with the type of the context.
5111 then
5118 then
5122 else
5127 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5128 -- multiplying operators from being used when the expected type is
5129 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5130 -- some cases where the expected type is actually Any_Real;
5131 -- Expected_Type_Is_Any_Real takes care of that case.
5135 then
5139 N_Unchecked_Type_Conversion)
5140 then
5147 else
5150 and then not
5152 N_Unchecked_Type_Conversion)
5153 then
5154 Error_Msg_N
5159 -- The expected type is "any real type" in contexts like
5161 -- type T is delta <universal_fixed-expression> ...
5163 -- in which case we need to set the type to Universal_Real
5164 -- so that static expression evaluation will work properly.
5168 else
5178 then
5183 -- If no previous errors, this is only possible if one operand is
5184 -- overloaded and the context is universal. Resolve as such.
5189 else
5191 and then
5193 then
5197 -- If the context is Universal_Fixed and the operands are also
5198 -- universal fixed, this is an error, unless there is only one
5199 -- applicable fixed_point type (usually Duration).
5207 else
5212 else
5217 -- If one of the arguments was resolved to a non-universal type.
5218 -- label the result of the operation itself with the same type.
5219 -- Do the same for the universal argument, if any.
5231 -- In SPARK, a multiplication or division with operands of fixed point
5232 -- types must be qualified or explicitly converted to identify the
5233 -- result type.
5238 and then
5240 then
5241 Check_SPARK_Restriction
5245 -- Set overflow and division checking bit
5252 -- Give warning if explicit division by zero
5256 then
5262 or else
5265 then
5266 -- Specialize the warning message according to the operation.
5267 -- The following warnings are for the case
5272 -- For division, we have two cases, for float division
5273 -- of an unconstrained float type, on a machine where
5274 -- Machine_Overflows is false, we don't get an exception
5275 -- at run-time, but rather an infinity or Nan. The Nan
5276 -- case is pretty obscure, so just warn about infinities.
5280 and then not Machine_Overflows_On_Target
5281 then
5282 Error_Msg_N
5286 -- For all other cases, we get a Constraint_Error
5288 else
5289 Apply_Compile_Time_Constraint_Error
5295 Apply_Compile_Time_Constraint_Error
5300 Apply_Compile_Time_Constraint_Error
5304 -- Division by zero can only happen with division, rem,
5305 -- and mod operations.
5311 -- Otherwise just set the flag to check at run time
5313 else
5318 -- If Restriction No_Implicit_Conditionals is active, then it is
5319 -- violated if either operand can be negative for mod, or for rem
5320 -- if both operands can be negative.
5324 then
5325 declare
5332 -- Set if corresponding operand might be negative
5334 begin
5335 Determine_Range
5339 Determine_Range
5343 -- Check if we will be generating conditionals. There are two
5344 -- cases where that can happen, first for REM, the only case
5345 -- is largest negative integer mod -1, where the division can
5346 -- overflow, but we still have to give the right result. The
5347 -- front end generates a test for this annoying case. Here we
5348 -- just test if both operands can be negative (that's what the
5349 -- expander does, so we match its logic here).
5351 -- The second case is mod where either operand can be negative.
5352 -- In this case, the back end has to generate additional tests.
5355 or else
5357 then
5369 ------------------
5370 -- Resolve_Call --
5371 ------------------
5374 function Same_Or_Aliased_Subprograms
5377 -- Returns True if the subprogram entity S is the same as E or else
5378 -- S is an alias of E.
5380 ---------------------------------
5381 -- Same_Or_Aliased_Subprograms --
5382 ---------------------------------
5384 function Same_Or_Aliased_Subprograms
5387 is
5389 begin
5393 -- Local variables
5407 -- Start of processing for Resolve_Call
5409 begin
5410 -- The context imposes a unique interpretation with type Typ on a
5411 -- procedure or function call. Find the entity of the subprogram that
5412 -- yields the expected type, and propagate the corresponding formal
5413 -- constraints on the actuals. The caller has established that an
5414 -- interpretation exists, and emitted an error if not unique.
5416 -- First deal with the case of a call to an access-to-subprogram,
5417 -- dereference made explicit in Analyze_Call.
5423 else
5424 -- Find the interpretation whose type (a subprogram type) has a
5425 -- return type that is compatible with the context. Analysis of
5426 -- the node has established that one exists.
5445 -- If the prefix is not an entity, then resolve it
5451 -- For an indirect call, we always invalidate checks, since we do not
5452 -- know whether the subprogram is local or global. Yes we could do
5453 -- better here, e.g. by knowing that there are no local subprograms,
5454 -- but it does not seem worth the effort. Similarly, we kill all
5455 -- knowledge of current constant values.
5457 Kill_Current_Values;
5459 -- If this is a procedure call which is really an entry call, do
5460 -- the conversion of the procedure call to an entry call. Protected
5461 -- operations use the same circuitry because the name in the call
5462 -- can be an arbitrary expression with special resolution rules.
5467 then
5471 -- Kill checks and constant values, as above for indirect case
5472 -- Who knows what happens when another task is activated?
5474 Kill_Current_Values;
5477 -- Normal subprogram call with name established in Resolve
5483 -- Otherwise we must have the case of an overloaded call
5485 else
5488 -- Initialize Nam to prevent warning (we know it will be assigned
5489 -- in the loop below, but the compiler does not know that).
5509 then
5510 -- The prefix is a parameterless function call that returns an access
5511 -- to subprogram. If parameters are present in the current call, add
5512 -- add an explicit dereference. We use the base type here because
5513 -- within an instance these may be subtypes.
5515 -- The dereference is added either in Analyze_Call or here. Should
5516 -- be consolidated ???
5525 -- Check that a call to Current_Task does not occur in an entry body
5528 declare
5531 begin
5533 loop
5536 -- Exclude calls that occur within the default of a formal
5537 -- parameter of the entry, since those are evaluated outside
5538 -- of the body.
5545 then
5548 Error_Msg_NE
5562 -- Check that a procedure call does not occur in the context of the
5563 -- entry call statement of a conditional or timed entry call. Note that
5564 -- the case of a call to a subprogram renaming of an entry will also be
5565 -- rejected. The test for N not being an N_Entry_Call_Statement is
5566 -- defensive, covering the possibility that the processing of entry
5567 -- calls might reach this point due to later modifications of the code
5568 -- above.
5573 then
5577 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5578 -- for a procedure_or_entry_call, the procedure_name or
5579 -- procedure_prefix of the procedure_call_statement shall denote
5580 -- an entry renamed by a procedure, or (a view of) a primitive
5581 -- subprogram of a limited interface whose first parameter is
5582 -- a controlling parameter.
5587 then
5588 Error_Msg_N
5593 -- If the SPARK_05 restriction is active, we are not allowed
5594 -- to have a call to a subprogram before we see its completion.
5599 -- Don't flag strange internal calls
5604 -- Only flag calls in extended main source
5609 -- Exclude enumeration literals from this processing
5612 then
5613 Check_SPARK_Restriction
5617 -- Check that this is not a call to a protected procedure or entry from
5618 -- within a protected function.
5622 -- Freeze the subprogram name if not in a spec-expression. Note that
5623 -- we freeze procedure calls as well as function calls. Procedure calls
5624 -- are not frozen according to the rules (RM 13.14(14)) because it is
5625 -- impossible to have a procedure call to a non-frozen procedure in
5626 -- pure Ada, but in the code that we generate in the expander, this
5627 -- rule needs extending because we can generate procedure calls that
5628 -- need freezing.
5630 -- In Ada 2012, expression functions may be called within pre/post
5631 -- conditions of subsequent functions or expression functions. Such
5632 -- calls do not freeze when they appear within generated bodies,
5633 -- (including the body of another expression function) which would
5634 -- place the freeze node in the wrong scope. An expression function
5635 -- is frozen in the usual fashion, by the appearance of a real body,
5636 -- or at the end of a declarative part.
5640 and then
5643 then
5647 -- For a predefined operator, the type of the result is the type imposed
5648 -- by context, except for a predefined operation on universal fixed.
5649 -- Otherwise The type of the call is the type returned by the subprogram
5650 -- being called.
5657 -- If the subprogram returns an array type, and the context requires the
5658 -- component type of that array type, the node is really an indexing of
5659 -- the parameterless call. Resolve as such. A pathological case occurs
5660 -- when the type of the component is an access to the array type. In
5661 -- this case the call is truly ambiguous.
5664 and then
5667 or else
5670 and then
5672 then
5673 declare
5678 begin
5681 then
5682 Error_Msg_N
5684 else
5687 -- The called entity may be an explicit dereference, in which
5688 -- case there is no entity to set.
5696 or else
5698 and then
5700 then
5703 -- Indexed call to a parameterless function
5705 Index_Node :=
5707 Prefix =>
5710 else
5711 -- An Ada 2005 prefixed call to a primitive operation
5712 -- whose first parameter is the prefix. This prefix was
5713 -- prepended to the parameter list, which is actually a
5714 -- list of indexes. Remove the prefix in order to build
5715 -- the proper indexed component.
5717 Index_Node :=
5719 Prefix =>
5722 Parameter_Associations =>
5723 New_List
5728 -- Preserve the parenthesis count of the node
5732 -- Since we are correcting a node classification error made
5733 -- by the parser, we call Replace rather than Rewrite.
5747 else
5751 -- In the case where the call is to an overloaded subprogram, Analyze
5752 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5753 -- such a case Normalize_Actuals needs to be called once more to order
5754 -- the actuals correctly. Otherwise the call will have the ordering
5755 -- given by the last overloaded subprogram whether this is the correct
5756 -- one being called or not.
5763 -- In any case, call is fully resolved now. Reset Overload flag, to
5764 -- prevent subsequent overload resolution if node is analyzed again
5769 -- If we are calling the current subprogram from immediately within its
5770 -- body, then that is the case where we can sometimes detect cases of
5771 -- infinite recursion statically. Do not try this in case restriction
5772 -- No_Recursion is in effect anyway, and do it only for source calls.
5777 -- Check violation of SPARK_05 restriction which does not permit
5778 -- a subprogram body to contain a call to the subprogram directly.
5782 then
5783 Check_SPARK_Restriction
5787 -- Issue warning for possible infinite recursion in the absence
5788 -- of the No_Recursion restriction.
5793 then
5794 -- Here we detected and flagged an infinite recursion, so we do
5795 -- not need to test the case below for further warnings. Also we
5796 -- are all done if we now have a raise SE node.
5802 -- If call is to immediately containing subprogram, then check for
5803 -- the case of a possible run-time detectable infinite recursion.
5805 else
5809 -- Although in general case, recursion is not statically
5810 -- checkable, the case of calling an immediately containing
5811 -- subprogram is easy to catch.
5815 -- If the recursive call is to a parameterless subprogram,
5816 -- then even if we can't statically detect infinite
5817 -- recursion, this is pretty suspicious, and we output a
5818 -- warning. Furthermore, we will try later to detect some
5819 -- cases here at run time by expanding checking code (see
5820 -- Detect_Infinite_Recursion in package Exp_Ch6).
5822 -- If the recursive call is within a handler, do not emit a
5823 -- warning, because this is a common idiom: loop until input
5824 -- is correct, catch illegal input in handler and restart.
5830 then
5831 -- For the case of a procedure call. We give the message
5832 -- only if the call is the first statement in a sequence
5833 -- of statements, or if all previous statements are
5834 -- simple assignments. This is simply a heuristic to
5835 -- decrease false positives, without losing too many good
5836 -- warnings. The idea is that these previous statements
5837 -- may affect global variables the procedure depends on.
5838 -- We also exclude raise statements, that may arise from
5839 -- constraint checks and are probably unrelated to the
5840 -- intended control flow.
5844 then
5845 declare
5847 begin
5851 N_Raise_Constraint_Error)
5852 then
5861 -- Do not give warning if we are in a conditional context
5863 declare
5865 begin
5871 then
5876 -- Here warning is to be issued
5892 -- Check obsolescent reference to Ada.Characters.Handling subprogram
5896 -- If subprogram name is a predefined operator, it was given in
5897 -- functional notation. Replace call node with operator node, so
5898 -- that actuals can be resolved appropriately.
5906 then
5912 -- Create a transient scope if the resulting type requires it
5914 -- There are several notable exceptions:
5916 -- a) In init procs, the transient scope overhead is not needed, and is
5917 -- even incorrect when the call is a nested initialization call for a
5918 -- component whose expansion may generate adjust calls. However, if the
5919 -- call is some other procedure call within an initialization procedure
5920 -- (for example a call to Create_Task in the init_proc of the task
5921 -- run-time record) a transient scope must be created around this call.
5923 -- b) Enumeration literal pseudo-calls need no transient scope
5925 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
5926 -- functions) do not use the secondary stack even though the return
5927 -- type may be unconstrained.
5929 -- d) Calls to a build-in-place function, since such functions may
5930 -- allocate their result directly in a target object, and cases where
5931 -- the result does get allocated in the secondary stack are checked for
5932 -- within the specialized Exp_Ch6 procedures for expanding those
5933 -- build-in-place calls.
5935 -- e) If the subprogram is marked Inline_Always, then even if it returns
5936 -- an unconstrained type the call does not require use of the secondary
5937 -- stack. However, inlining will only take place if the body to inline
5938 -- is already present. It may not be available if e.g. the subprogram is
5939 -- declared in a child instance.
5941 -- If this is an initialization call for a type whose construction
5942 -- uses the secondary stack, and it is not a nested call to initialize
5943 -- a component, we do need to create a transient scope for it. We
5944 -- check for this by traversing the type in Check_Initialization_Call.
5950 then
5956 then
5959 elsif Expander_Active
5962 and then
5964 or else
5966 then
5969 -- If the call appears within the bounds of a loop, it will
5970 -- be rewritten and reanalyzed, nothing left to do here.
5977 and then not Within_Init_Proc
5978 then
5982 -- A protected function cannot be called within the definition of the
5983 -- enclosing protected type.
5988 then
5989 Error_Msg_NE
5993 -- Propagate interpretation to actuals, and add default expressions
5994 -- where needed.
5999 -- Overloaded literals are rewritten as function calls, for purpose of
6000 -- resolution. After resolution, we can replace the call with the
6001 -- literal itself.
6007 -- Avoid validation, since it is a static function call
6013 -- If the subprogram is not global, then kill all saved values and
6014 -- checks. This is a bit conservative, since in many cases we could do
6015 -- better, but it is not worth the effort. Similarly, we kill constant
6016 -- values. However we do not need to do this for internal entities
6017 -- (unless they are inherited user-defined subprograms), since they
6018 -- are not in the business of molesting local values.
6020 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6021 -- kill all checks and values for calls to global subprograms. This
6022 -- takes care of the case where an access to a local subprogram is
6023 -- taken, and could be passed directly or indirectly and then called
6024 -- from almost any context.
6026 -- Note: we do not do this step till after resolving the actuals. That
6027 -- way we still take advantage of the current value information while
6028 -- scanning the actuals.
6030 -- We suppress killing values if we are processing the nodes associated
6031 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6032 -- type kills all the values as part of analyzing the code that
6033 -- initializes the dispatch tables.
6037 or else Suppress_Value_Tracking_On_Call
6042 then
6043 Kill_Current_Values;
6046 -- If we are warning about unread OUT parameters, this is the place to
6047 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6048 -- after the above call to Kill_Current_Values (since that call clears
6049 -- the Last_Assignment field of all local variables).
6054 then
6055 declare
6059 begin
6069 then
6079 -- If the subprogram is a primitive operation, check whether or not
6080 -- it is a correct dispatching call.
6084 then
6089 and then not In_Instance
6090 then
6094 -- If this is a dispatching call, generate the appropriate reference,
6095 -- for better source navigation in GPS.
6099 then
6102 -- Normal case, not a dispatching call: generate a call reference
6104 else
6112 -- Check for violation of restriction No_Specific_Termination_Handlers
6113 -- and warn on a potentially blocking call to Abort_Task.
6117 or else
6119 then
6126 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6127 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6128 -- need to check the second argument to determine whether it is an
6129 -- absolute or relative timing event.
6134 then
6138 -- Issue an error for a call to an eliminated subprogram. This routine
6139 -- will not perform the check if the call appears within a default
6140 -- expression.
6144 -- In formal mode, the primitive operations of a tagged type or type
6145 -- extension do not include functions that return the tagged type.
6151 then
6155 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6156 -- class-wide and the call dispatches on result in a context that does
6157 -- not provide a tag, the call raises Program_Error.
6160 and then In_Instance
6165 then
6166 -- Verify that none of the formals are controlling
6168 declare
6172 begin
6194 -- Check for calling a function with OUT or IN OUT parameter when the
6195 -- calling context (us right now) is not Ada 2012, so does not allow
6196 -- OUT or IN OUT parameters in function calls.
6201 then
6206 -- Check the dimensions of the actuals in the call. For function calls,
6207 -- propagate the dimensions from the returned type to N.
6211 -- All done, evaluate call and deal with elaboration issues
6216 -- In GNATprove mode, expansion is disabled, but we want to inline some
6217 -- subprograms to facilitate formal verification. Indirect calls through
6218 -- a subprogram type or within a generic cannot be inlined. Inlining is
6219 -- performed only for calls subject to SPARK_Mode on.
6221 if GNATprove_Mode
6224 and then not Inside_A_Generic
6225 then
6232 -- Nothing to do if the subprogram is not eligible for inlining in
6233 -- GNATprove mode.
6237 then
6240 -- Calls cannot be inlined inside assertions, as GNATprove treats
6241 -- assertions as logic expressions.
6248 -- Calls cannot be inlined inside default expressions
6255 -- Inlining should not be performed during pre-analysis
6259 -- With the one-pass inlining technique, a call cannot be
6260 -- inlined if the corresponding body has not been seen yet.
6263 Error_Msg_NE
6268 -- Nothing to do if there is no body to inline, indicating that
6269 -- the subprogram is not suitable for inlining in GNATprove
6270 -- mode.
6275 -- Calls cannot be inlined inside potentially unevaluated
6276 -- expressions, as this would create complex actions inside
6277 -- expressions, that are not handled by GNATprove.
6281 Error_Msg_N
6285 -- Otherwise, inline the call
6287 else
6297 -----------------------------
6298 -- Resolve_Case_Expression --
6299 -----------------------------
6304 begin
6315 -------------------------------
6316 -- Resolve_Character_Literal --
6317 -------------------------------
6323 begin
6324 -- Verify that the character does belong to the type of the context
6329 -- Wide_Wide_Character literals must always be defined, since the set
6330 -- of wide wide character literals is complete, i.e. if a character
6331 -- literal is accepted by the parser, then it is OK for wide wide
6332 -- character (out of range character literals are rejected).
6337 -- Always accept character literal for type Any_Character, which
6338 -- occurs in error situations and in comparisons of literals, both
6339 -- of which should accept all literals.
6344 -- For Standard.Character or a type derived from it, check that the
6345 -- literal is in range.
6352 -- For Standard.Wide_Character or a type derived from it, check that the
6353 -- literal is in range.
6360 -- For Standard.Wide_Wide_Character or a type derived from it, we
6361 -- know the literal is in range, since the parser checked.
6366 -- If the entity is already set, this has already been resolved in a
6367 -- generic context, or comes from expansion. Nothing else to do.
6372 -- Otherwise we have a user defined character type, and we can use the
6373 -- standard visibility mechanisms to locate the referenced entity.
6375 else
6388 -- If we fall through, then the literal does not match any of the
6389 -- entries of the enumeration type. This isn't just a constraint error
6390 -- situation, it is an illegality (see RM 4.2).
6392 Error_Msg_NE
6396 ---------------------------
6397 -- Resolve_Comparison_Op --
6398 ---------------------------
6400 -- Context requires a boolean type, and plays no role in resolution.
6401 -- Processing identical to that for equality operators. The result type is
6402 -- the base type, which matters when pathological subtypes of booleans with
6403 -- limited ranges are used.
6410 begin
6411 -- If this is an intrinsic operation which is not predefined, use the
6412 -- types of its declared arguments to resolve the possibly overloaded
6413 -- operands. Otherwise the operands are unambiguous and specify the
6414 -- expected type.
6419 else
6430 -- Skip remaining processing if already set to Any_Type
6436 -- Deal with other error cases
6440 T = Any_Character
6441 then
6444 else
6452 -- Resolve the operands if types OK
6461 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6462 -- types or array types except String.
6465 Check_SPARK_Restriction
6470 then
6471 Check_SPARK_Restriction
6475 -- Check comparison on unordered enumeration
6479 Error_Msg_NE
6484 -- Evaluate the relation (note we do this after the above check since
6485 -- this Eval call may change N to True/False.
6491 -----------------------------------------
6492 -- Resolve_Discrete_Subtype_Indication --
6493 -----------------------------------------
6495 procedure Resolve_Discrete_Subtype_Indication
6498 is
6502 begin
6510 else
6520 Error_Msg_NE
6523 -- Rewrite the constraint as a range of Typ
6524 -- to allow compilation to proceed further.
6536 else
6540 -- Additionally, we must check that the bounds are compatible
6541 -- with the given subtype, which might be different from the
6542 -- type of the context.
6546 -- ??? If the above check statically detects a Constraint_Error
6547 -- it replaces the offending bound(s) of the range R with a
6548 -- Constraint_Error node. When the itype which uses these bounds
6549 -- is frozen the resulting call to Duplicate_Subexpr generates
6550 -- a new temporary for the bounds.
6552 -- Unfortunately there are other itypes that are also made depend
6553 -- on these bounds, so when Duplicate_Subexpr is called they get
6554 -- a forward reference to the newly created temporaries and Gigi
6555 -- aborts on such forward references. This is probably sign of a
6556 -- more fundamental problem somewhere else in either the order of
6557 -- itype freezing or the way certain itypes are constructed.
6559 -- To get around this problem we call Remove_Side_Effects right
6560 -- away if either bounds of R are a Constraint_Error.
6562 declare
6566 begin
6582 -------------------------
6583 -- Resolve_Entity_Name --
6584 -------------------------
6586 -- Used to resolve identifiers and expanded names
6590 -- Denote whether an arbitrary node Nod appears in a check node
6592 function Is_OK_Volatile_Context
6595 -- Determine whether node Context denotes a "non-interfering context"
6596 -- (as defined in SPARK RM 7.1.3(13)) where volatile reference Obj_Ref
6597 -- can safely reside.
6599 ----------------------
6600 -- Appears_In_Check --
6601 ----------------------
6606 begin
6607 -- Climb the parent chain looking for a check node
6614 -- Prevent the search from going too far
6626 ----------------------------
6627 -- Is_OK_Volatile_Context --
6628 ----------------------------
6630 function Is_OK_Volatile_Context
6633 is
6634 begin
6635 -- The volatile object appears on either side of an assignment
6640 -- The volatile object is part of the initialization expression of
6641 -- another object. Ensure that the climb of the parent chain came
6642 -- from the expression side and not from the name side.
6647 then
6650 -- The volatile object appears as an actual parameter in a call to an
6651 -- instance of Unchecked_Conversion whose result is renamed.
6656 then
6659 -- The volatile object appears as the prefix of a name occurring
6660 -- in a non-interfering context.
6663 N_Indexed_Component,
6664 N_Selected_Component,
6665 N_Slice)
6667 and then Is_OK_Volatile_Context
6670 then
6673 -- Allow references to volatile objects in various checks. This is
6674 -- not a direct SPARK 2014 requirement.
6679 else
6684 -- Local variables
6689 -- Start of processing for Resolve_Entity_Name
6691 begin
6692 -- If garbage from errors, set to Any_Type and return
6699 -- Replace named numbers by corresponding literals. Note that this is
6700 -- the one case where Resolve_Entity_Name must reset the Etype, since
6701 -- it is currently marked as universal.
6711 -- For enumeration literals, we need to make sure that a proper style
6712 -- check is done, since such literals are overloaded, and thus we did
6713 -- not do a style check during the first phase of analysis.
6719 -- Case of subtype name appearing as an operand in expression
6723 -- Allow use of subtype if it is a concurrent type where we are
6724 -- currently inside the body. This will eventually be expanded into a
6725 -- call to Self (for tasks) or _object (for protected objects). Any
6726 -- other use of a subtype is invalid.
6730 then
6733 -- Any other use is an error
6735 else
6736 Error_Msg_N
6740 -- Check discriminant use if entity is discriminant in current scope,
6741 -- i.e. discriminant of record or concurrent type currently being
6742 -- analyzed. Uses in corresponding body are unrestricted.
6747 then
6750 -- A parameterless generic function cannot appear in a context that
6751 -- requires resolution.
6762 then
6765 -- In all other cases, just do the possible static evaluation
6767 else
6768 -- A deferred constant that appears in an expression must have a
6769 -- completion, unless it has been removed by in-place expansion of
6770 -- an aggregate.
6776 and then not In_Spec_Expression
6778 then
6782 then
6784 else
6785 Error_Msg_N (
6793 -- An effectively volatile object subject to enabled properties
6794 -- Async_Writers or Effective_Reads must appear in a specific context.
6795 -- The following checks are only relevant when SPARK_Mode is on as they
6796 -- are not standard Ada legality rules.
6802 and then
6804 then
6805 -- The effectively volatile objects appears in a "non-interfering
6806 -- context" as defined in SPARK RM 7.1.3(13).
6811 -- Assume that references to effectively volatile objects that appear
6812 -- as actual parameters in a procedure call are always legal. The
6813 -- full legality check is done when the actuals are resolved.
6818 -- Otherwise the context causes a side effect with respect to the
6819 -- effectively volatile object.
6821 else
6822 Error_Msg_N
6829 -------------------
6830 -- Resolve_Entry --
6831 -------------------
6843 -- If the bounds of the entry family being called depend on task
6844 -- discriminants, build a new index subtype where a discriminant is
6845 -- replaced with the value of the discriminant of the target task.
6846 -- The target task is the prefix of the entry name in the call.
6848 -----------------------
6849 -- Actual_Index_Type --
6850 -----------------------
6860 -- If the bound is given by a discriminant, replace with a reference
6861 -- to the discriminant of the same name in the target task. If the
6862 -- entry name is the target of a requeue statement and the entry is
6863 -- in the current protected object, the bound to be used is the
6864 -- discriminal of the object (see Apply_Range_Checks for details of
6865 -- the transformation).
6867 -----------------------------
6868 -- Actual_Discriminant_Ref --
6869 -----------------------------
6875 begin
6880 then
6886 then
6887 -- Note: here Bound denotes a discriminant of the corresponding
6888 -- record type tskV, whose discriminal is a formal of the
6889 -- init-proc tskVIP. What we want is the body discriminal,
6890 -- which is associated to the discriminant of the original
6891 -- concurrent type tsk.
6893 return New_Occurrence_Of
6896 else
6897 Ref :=
6907 -- Start of processing for Actual_Index_Type
6909 begin
6912 then
6915 else
6929 -- Start of processing of Resolve_Entry
6931 begin
6932 -- Find name of entry being called, and resolve prefix of name with its
6933 -- own type. The prefix can be overloaded, and the name and signature of
6934 -- the entry must be taken into account.
6938 -- Case of dealing with entry family within the current tasks
6942 else
6948 -- Entry call to an entry (or entry family) in the current task. This
6949 -- is legal even though the task will deadlock. Rewrite as call to
6950 -- current task.
6952 -- This can also be a call to an entry in an enclosing task. If this
6953 -- is a single task, we have to retrieve its name, because the scope
6954 -- of the entry is the task type, not the object. If the enclosing
6955 -- task is a task type, the identity of the task is given by its own
6956 -- self variable.
6958 -- Finally this can be a requeue on an entry of the same task or
6959 -- protected object.
6966 then
6967 -- S is an enclosing task or protected object. The concurrent
6968 -- declaration has been converted into a type declaration, and
6969 -- the object itself has an object declaration that follows
6970 -- the type in the same declarative part.
6982 -- Call to current task. Will be transformed into call to Self
6989 New_N :=
6992 Selector_Name =>
6999 then
7000 -- Use the entry name (which must be unique at this point) to find
7001 -- the prefix that returns the corresponding task/protected type.
7003 declare
7009 begin
7031 -- Up to this point the expression could have been the actual in a
7032 -- simple entry call, and be given by a named association.
7036 else
7042 ------------------------
7043 -- Resolve_Entry_Call --
7044 ------------------------
7056 begin
7057 -- We kill all checks here, because it does not seem worth the effort to
7058 -- do anything better, an entry call is a big operation.
7060 Kill_All_Checks;
7062 -- Processing of the name is similar for entry calls and protected
7063 -- operation calls. Once the entity is determined, we can complete
7064 -- the resolution of the actuals.
7066 -- The selector may be overloaded, in the case of a protected object
7067 -- with overloaded functions. The type of the context is used for
7068 -- resolution.
7073 then
7074 declare
7078 begin
7097 -- Simple entry call
7105 -- Call to member of entry family
7112 -- We cannot in general check the maximum depth of protected entry calls
7113 -- at compile time. But we can tell that any protected entry call at all
7114 -- violates a specified nesting depth of zero.
7120 -- Use context type to disambiguate a protected function that can be
7121 -- called without actuals and that returns an array type, and where the
7122 -- argument list may be an indexing of the returned value.
7127 and then
7133 and then
7134 Covers
7137 then
7138 declare
7141 begin
7142 Index_Node :=
7144 Prefix =>
7148 -- Since we are correcting a node classification error made by the
7149 -- parser, we call Replace rather than Rewrite.
7162 then
7163 -- Rewrite as call to the precondition wrapper, adding the task
7164 -- object to the list of actuals. If the call is to a member of an
7165 -- entry family, include the index as well.
7167 declare
7171 begin
7180 New_Call :=
7182 Name =>
7187 -- Preanalyze and resolve new call. Current procedure is called
7188 -- from Resolve_Call, after which expansion will take place.
7195 -- The operation name may have been overloaded. Order the actuals
7196 -- according to the formals of the resolved entity, and set the return
7197 -- type to that of the operation.
7208 -- Create a call reference to the entry
7216 -- Verify that a procedure call cannot masquerade as an entry
7217 -- call where an entry call is expected.
7222 then
7227 then
7232 then
7237 -- After resolution, entry calls and protected procedure calls are
7238 -- changed into entry calls, for expansion. The structure of the node
7239 -- does not change, so it can safely be done in place. Protected
7240 -- function calls must keep their structure because they are
7241 -- subexpressions.
7245 -- A protected operation that is not a function may modify the
7246 -- corresponding object, and cannot apply to a constant. If this
7247 -- is an internal call, the prefix is the type itself.
7253 then
7254 Error_Msg_N
7256 Entry_Name);
7270 -- Protected functions can return on the secondary stack, in which
7271 -- case we must trigger the transient scope mechanism.
7273 elsif Expander_Active
7275 then
7280 -------------------------
7281 -- Resolve_Equality_Op --
7282 -------------------------
7284 -- Both arguments must have the same type, and the boolean context does
7285 -- not participate in the resolution. The first pass verifies that the
7286 -- interpretation is not ambiguous, and the type of the left argument is
7287 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7288 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7289 -- though they carry a single (universal) type. Diagnose this case here.
7297 -- The resolution rule for if expressions requires that each such must
7298 -- have a unique type. This means that if several dependent expressions
7299 -- are of a non-null anonymous access type, and the context does not
7300 -- impose an expected type (as can be the case in an equality operation)
7301 -- the expression must be rejected.
7304 -- Attempt to explain the nature of a redundant comparison with True. If
7305 -- the expression N is too complex, this routine issues a general error
7306 -- message.
7309 -- In the case of allocators and access attributes, the context must
7310 -- provide an indication of the specific access type to be used. If
7311 -- one operand is of such a "generic" access type, check whether there
7312 -- is a specific visible access type that has the same designated type.
7313 -- This is semantically dubious, and of no interest to any real code,
7314 -- but c48008a makes it all worthwhile.
7316 -------------------------
7317 -- Check_If_Expression --
7318 -------------------------
7324 begin
7331 then
7337 ------------------------
7338 -- Explain_Redundancy --
7339 ------------------------
7346 begin
7349 -- Strip the operand down to an entity
7351 loop
7354 else
7359 -- The construct denotes an entity
7364 -- Do not generate an error message when the comparison is done
7365 -- against the enumeration literal Standard.True.
7369 -- Build a customized error message
7396 -- The construct is too complex to disect, issue a general message
7398 else
7403 -----------------------------
7404 -- Find_Unique_Access_Type --
7405 -----------------------------
7412 begin
7414 E_Access_Attribute_Type)
7415 then
7419 E_Access_Attribute_Type)
7420 then
7422 else
7434 then
7447 -- Start of processing for Resolve_Equality_Op
7449 begin
7460 T = Any_Character
7461 then
7464 else
7473 then
7482 -- If expressions must have a single type, and if the context does
7483 -- not impose one the dependent expressions cannot be anonymous
7484 -- access types.
7486 -- Why no similar processing for case expressions???
7490 E_Anonymous_Access_Subprogram_Type)
7492 E_Anonymous_Access_Subprogram_Type)
7493 then
7501 -- In SPARK, equality operators = and /= for array types other than
7502 -- String are only defined when, for each index position, the
7503 -- operands have equal static bounds.
7507 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7508 -- operation if not needed.
7516 then
7517 Check_SPARK_Restriction
7522 -- If the unique type is a class-wide type then it will be expanded
7523 -- into a dispatching call to the predefined primitive. Therefore we
7524 -- check here for potential violation of such restriction.
7530 if Warn_On_Redundant_Constructs
7535 then
7536 Error_Msg_N -- CODEFIX
7546 -- If this is an inequality, it may be the implicit inequality
7547 -- created for a user-defined operation, in which case the corres-
7548 -- ponding equality operation is not intrinsic, and the operation
7549 -- cannot be constant-folded. Else fold.
7554 or else Is_Intrinsic_Subprogram
7556 then
7562 then
7566 -- Ada 2005: If one operand is an anonymous access type, convert the
7567 -- other operand to it, to ensure that the underlying types match in
7568 -- the back-end. Same for access_to_subprogram, and the conversion
7569 -- verifies that the types are subtype conformant.
7571 -- We apply the same conversion in the case one of the operands is a
7572 -- private subtype of the type of the other.
7574 -- Why the Expander_Active test here ???
7576 if Expander_Active
7577 and then
7579 E_Anonymous_Access_Subprogram_Type)
7581 then
7601 ----------------------------------
7602 -- Resolve_Explicit_Dereference --
7603 ----------------------------------
7611 -- The candidate prefix type, if overloaded
7616 begin
7620 -- A useful optimization: check whether the dereference denotes an
7621 -- element of a container, and if so rewrite it as a call to the
7622 -- corresponding Element function.
7624 -- Disabled for now, on advice of ARG. A more restricted form of the
7625 -- predicate might be acceptable ???
7627 -- if Is_Container_Element (N) then
7628 -- return;
7629 -- end if;
7633 -- Use the context type to select the prefix that has the correct
7634 -- designated type. Keep the first match, which will be the inner-
7635 -- most.
7642 then
7647 -- Remove access types that do not match, but preserve access
7648 -- to subprogram interpretations, in case a further dereference
7649 -- is needed (see below).
7662 else
7663 -- If no interpretation covers the designated type of the prefix,
7664 -- this is the pathological case where not all implementations of
7665 -- the prefix allow the interpretation of the node as a call. Now
7666 -- that the expected type is known, Remove other interpretations
7667 -- from prefix, rewrite it as a call, and resolve again, so that
7668 -- the proper call node is generated.
7679 New_N :=
7681 Name =>
7692 -- If not overloaded, resolve P with its own type
7694 else
7702 -- If the designated type is a packed unconstrained array type, and the
7703 -- explicit dereference is not in the context of an attribute reference,
7704 -- then we must compute and set the actual subtype, since it is needed
7705 -- by Gigi. The reason we exclude the attribute case is that this is
7706 -- handled fine by Gigi, and in fact we use such attributes to build the
7707 -- actual subtype. We also exclude generated code (which builds actual
7708 -- subtypes directly if they are needed).
7715 then
7719 -- Note: No Eval processing is required for an explicit dereference,
7720 -- because such a name can never be static.
7724 -------------------------------------
7725 -- Resolve_Expression_With_Actions --
7726 -------------------------------------
7729 begin
7732 -- If N has no actions, and its expression has been constant folded,
7733 -- then rewrite N as just its expression. Note, we can't do this in
7734 -- the general case of Is_Empty_List (Actions (N)) as this would cause
7735 -- Expression (N) to be expanded again.
7739 then
7744 ----------------------------------
7745 -- Resolve_Generalized_Indexing --
7746 ----------------------------------
7754 begin
7755 -- In ASIS mode, propagate the information about the indices back to
7756 -- to the original indexing node. The generalized indexing is either
7757 -- a function call, or a dereference of one. The actuals include the
7758 -- prefix of the original node, which is the container expression.
7767 loop
7778 else
7784 ---------------------------
7785 -- Resolve_If_Expression --
7786 ---------------------------
7795 begin
7800 -- When the "then" expression is of a scalar subtype different from the
7801 -- result subtype, then insert a conversion to ensure the generation of
7802 -- a constraint check. The same is done for the else part below, again
7803 -- comparing subtypes rather than base types.
7807 then
7812 -- If ELSE expression present, just resolve using the determined type
7820 then
7825 -- If no ELSE expression is present, root type must be Standard.Boolean
7826 -- and we provide a Standard.True result converted to the appropriate
7827 -- Boolean type (in case it is a derived boolean type).
7830 Else_Expr :=
7835 else
7844 -------------------------------
7845 -- Resolve_Indexed_Component --
7846 -------------------------------
7854 begin
7862 -- Use the context type to select the prefix that yields the correct
7863 -- component type.
7865 declare
7872 begin
7879 and then
7880 Covers
7883 then
7892 else
7898 else
7909 else
7916 -- If prefix is access type, dereference to get real array type.
7917 -- Note: we do not apply an access check because the expander always
7918 -- introduces an explicit dereference, and the check will happen there.
7924 -- If name was overloaded, set component type correctly now
7925 -- If a misplaced call to an entry family (which has no index types)
7926 -- return. Error will be diagnosed from calling context.
7930 else
7937 -- The prefix may have resolved to a string literal, in which case its
7938 -- etype has a special representation. This is only possible currently
7939 -- if the prefix is a static concatenation, written in functional
7940 -- notation.
7945 else
7952 else
7963 -- Do not generate the warning on suspicious index if we are analyzing
7964 -- package Ada.Tags; otherwise we will report the warning with the
7965 -- Prims_Ptr field of the dispatch table.
7968 or else not
7970 Ada_Tags)
7971 then
7976 -- If the array type is atomic, and is packed, and we are in a left side
7977 -- context, then this is worth a warning, since we have a situation
7978 -- where the access to the component may cause extra read/writes of
7979 -- the atomic array object, which could be considered unexpected.
7987 then
7995 -----------------------------
7996 -- Resolve_Integer_Literal --
7997 -----------------------------
8000 begin
8005 --------------------------------
8006 -- Resolve_Intrinsic_Operator --
8007 --------------------------------
8016 -- If the operand is a literal, it cannot be the expression in a
8017 -- conversion. Use a qualified expression instead.
8022 begin
8024 Res :=
8030 else
8037 -- Start of processing for Resolve_Intrinsic_Operator
8039 begin
8040 -- We must preserve the original entity in a generic setting, so that
8041 -- the legality of the operation can be verified in an instance.
8056 -- If the result or operand types are private, rewrite with unchecked
8057 -- conversions on the operands and the result, to expose the proper
8058 -- underlying numeric type.
8063 then
8065 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
8066 -- What on earth is this commented out fragment of code???
8070 else
8091 then
8092 -- Add explicit conversion where needed, and save interpretations in
8093 -- case operands are overloaded.
8100 else
8106 else
8116 else
8121 --------------------------------------
8122 -- Resolve_Intrinsic_Unary_Operator --
8123 --------------------------------------
8125 procedure Resolve_Intrinsic_Unary_Operator
8128 is
8133 begin
8152 else
8157 ------------------------
8158 -- Resolve_Logical_Op --
8159 ------------------------
8164 begin
8167 -- Predefined operations on scalar types yield the base type. On the
8168 -- other hand, logical operations on arrays yield the type of the
8169 -- arguments (and the context).
8173 else
8177 -- The following test is required because the operands of the operation
8178 -- may be literals, in which case the resulting type appears to be
8179 -- compatible with a signed integer type, when in fact it is compatible
8180 -- only with modular types. If the context itself is universal, the
8181 -- operation is illegal.
8189 Error_Msg_N
8197 then
8201 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8202 -- is active and the result type is standard Boolean (do not mess with
8203 -- ops that return a nonstandard Boolean type, because something strange
8204 -- is going on).
8206 -- Note: you might expect this replacement to be done during expansion,
8207 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8208 -- is used, no part of the right operand of an "and" or "or" operator
8209 -- should be executed if the left operand would short-circuit the
8210 -- evaluation of the corresponding "and then" or "or else". If we left
8211 -- the replacement to expansion time, then run-time checks associated
8212 -- with such operands would be evaluated unconditionally, due to being
8213 -- before the condition prior to the rewriting as short-circuit forms
8214 -- during expansion.
8216 if Short_Circuit_And_Or
8219 then
8227 -- Case of OR changed to OR ELSE
8229 else
8237 -- Return now, since analysis of the rewritten ops will take care of
8238 -- other reference bookkeeping and expression folding.
8253 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8254 -- only when both operands have same static lower and higher bounds. Of
8255 -- course the types have to match, so only check if operands are
8256 -- compatible and the node itself has no errors.
8260 then
8261 declare
8265 begin
8266 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8267 -- operation if not needed.
8274 then
8275 Check_SPARK_Restriction
8284 ---------------------------
8285 -- Resolve_Membership_Op --
8286 ---------------------------
8288 -- The context can only be a boolean type, and does not determine the
8289 -- arguments. Arguments should be unambiguous, but the preference rule for
8290 -- universal types applies.
8300 -- Analysis has determined a unique type for the left operand. Use it to
8301 -- resolve the disjuncts.
8303 ----------------------------
8304 -- Resolve_Set_Membership --
8305 ----------------------------
8311 begin
8317 -- Alternative is an expression, a range
8318 -- or a subtype mark.
8322 then
8329 -- Check for duplicates for discrete case
8332 declare
8341 begin
8342 -- Loop checking duplicates. This is quadratic, but giant sets
8343 -- are unlikely in this context so it's a reasonable choice.
8350 N_Character_Literal)
8352 then
8370 -- Start of processing for Resolve_Membership_Op
8372 begin
8378 Resolve_Set_Membership;
8382 and then
8384 or else
8387 then
8390 -- Ada 2005 (AI-251): Support the following case:
8392 -- type I is interface;
8393 -- type T is tagged ...
8395 -- function Test (O : I'Class) is
8396 -- begin
8397 -- return O in T'Class.
8398 -- end Test;
8400 -- In this case we have nothing else to do. The membership test will be
8401 -- done at run time.
8408 then
8410 else
8414 -- If mixed-mode operations are present and operands are all literal,
8415 -- the only interpretation involves Duration, which is probably not
8416 -- the intention of the programmer.
8431 then
8437 else
8442 -- Here after resolving membership operation
8450 ------------------
8451 -- Resolve_Null --
8452 ------------------
8457 begin
8458 -- Handle restriction against anonymous null access values This
8459 -- restriction can be turned off using -gnatdj.
8461 -- Ada 2005 (AI-231): Remove restriction
8464 and then not Debug_Flag_J
8467 then
8468 -- In the common case of a call which uses an explicitly null value
8469 -- for an access parameter, give specialized error message.
8472 Error_Msg_N
8475 -- Standard message for all other cases (are there any?)
8477 else
8478 Error_Msg_N
8483 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8484 -- assignment to a null-excluding object
8489 then
8491 Insert_Action
8496 else
8503 -- In a distributed context, null for a remote access to subprogram may
8504 -- need to be replaced with a special record aggregate. In this case,
8505 -- return after having done the transformation.
8510 then
8514 -- The null literal takes its type from the context
8519 -----------------------
8520 -- Resolve_Op_Concat --
8521 -----------------------
8525 -- We wish to avoid deep recursion, because concatenations are often
8526 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
8527 -- operands nonrecursively until we find something that is not a simple
8528 -- concatenation (A in this case). We resolve that, and then walk back
8529 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
8530 -- to do the rest of the work at each level. The Parent pointers allow
8531 -- us to avoid recursion, and thus avoid running out of memory. See also
8532 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
8537 begin
8538 -- The following code is equivalent to:
8540 -- Resolve_Op_Concat_First (NN, Typ);
8541 -- Resolve_Op_Concat_Arg (N, ...);
8542 -- Resolve_Op_Concat_Rest (N, Typ);
8544 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
8545 -- operand is a concatenation.
8547 -- Walk down left operands
8549 loop
8558 -- Now (given the above example) NN is A&B and Op1 is A
8560 -- First resolve Op1 ...
8564 -- ... then walk NN back up until we reach N (where we started), calling
8565 -- Resolve_Op_Concat_Rest along the way.
8567 loop
8574 Check_SPARK_Restriction
8579 ---------------------------
8580 -- Resolve_Op_Concat_Arg --
8581 ---------------------------
8583 procedure Resolve_Op_Concat_Arg
8588 is
8592 begin
8594 if Is_Comp
8598 then
8600 else
8604 -- If both Array & Array and Array & Component are visible, there is a
8605 -- potential ambiguity that must be reported.
8610 then
8614 -- If the operation is user-defined and not overloaded use its
8615 -- profile. The operation may be a renaming, in which case it has
8616 -- been rewritten, and we want the original profile.
8621 then
8623 Etype
8627 -- Otherwise an aggregate may match both the array type and the
8628 -- component type.
8630 else
8635 else
8639 then
8640 declare
8645 begin
8650 -- Special-case the error message when the overloading is
8651 -- caused by a function that yields an array and can be
8652 -- called without parameters.
8657 Error_Msg_NE
8659 Error_Msg_NE
8663 else
8671 or else
8673 then
8674 Error_Msg_N -- CODEFIX
8692 else
8697 else
8701 -- Concatenation is restricted in SPARK: each operand must be either a
8702 -- string literal, the name of a string constant, a static character or
8703 -- string expression, or another concatenation. Arg cannot be a
8704 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
8705 -- separately on each final operand, past concatenation operations.
8709 Check_SPARK_Restriction
8717 then
8718 Check_SPARK_Restriction
8722 -- Do not issue error on an operand that is neither a character nor a
8723 -- string, as the error is issued in Resolve_Op_Concat.
8725 else
8732 -----------------------------
8733 -- Resolve_Op_Concat_First --
8734 -----------------------------
8741 begin
8742 -- The parser folds an enormous sequence of concatenations of string
8743 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
8744 -- in the right operand. If the expression resolves to a predefined "&"
8745 -- operator, all is well. Otherwise, the parser's folding is wrong, so
8746 -- we give an error. See P_Simple_Expression in Par.Ch4.
8751 then
8766 ----------------------------
8767 -- Resolve_Op_Concat_Rest --
8768 ----------------------------
8774 begin
8783 -- If this is not a static concatenation, but the result is a string
8784 -- type (and not an array of strings) ensure that static string operands
8785 -- have their subtypes properly constructed.
8789 then
8795 ----------------------
8796 -- Resolve_Op_Expon --
8797 ----------------------
8802 begin
8803 -- Catch attempts to do fixed-point exponentiation with universal
8804 -- operands, which is a case where the illegality is not caught during
8805 -- normal operator analysis. This is not done in preanalysis mode
8806 -- since the tree is not fully decorated during preanalysis.
8817 then
8827 then
8834 then
8838 -- We do the resolution using the base type, because intermediate values
8839 -- in expressions are always of the base type, not a subtype of it.
8844 -- For integer types, right argument must be in Natural range
8859 -- Evaluate the exponentiation operator for dimensioned type
8862 else
8866 -- Set overflow checking bit. Much cleverer code needed here eventually
8867 -- and perhaps the Resolve routines should be separated for the various
8868 -- arithmetic operations, since they will need different processing. ???
8877 --------------------
8878 -- Resolve_Op_Not --
8879 --------------------
8885 -- This function determines if the parent node is a boolean operator or
8886 -- operation (comparison op, membership test, or short circuit form) and
8887 -- the not in question is the left operand of this operation. Note that
8888 -- if the not is in parens, then false is returned.
8890 -----------------------
8891 -- Parent_Is_Boolean --
8892 -----------------------
8895 begin
8899 else
8901 when N_Op_And |
8902 N_Op_Eq |
8903 N_Op_Ge |
8904 N_Op_Gt |
8905 N_Op_Le |
8906 N_Op_Lt |
8907 N_Op_Ne |
8908 N_Op_Or |
8909 N_Op_Xor |
8910 N_In |
8911 N_Not_In |
8912 N_And_Then |
8913 N_Or_Else =>
8923 -- Start of processing for Resolve_Op_Not
8925 begin
8926 -- Predefined operations on scalar types yield the base type. On the
8927 -- other hand, logical operations on arrays yield the type of the
8928 -- arguments (and the context).
8932 else
8936 -- Straightforward case of incorrect arguments
8943 -- Special case of probable missing parens
8947 Error_Msg_N
8950 else
8951 Error_Msg_N
8958 -- OK resolution of NOT
8960 else
8961 -- Warn if non-boolean types involved. This is a case like not a < b
8962 -- where a and b are modular, where we will get (not a) < b and most
8963 -- likely not (a < b) was intended.
8965 if Warn_On_Questionable_Missing_Parens
8967 and then Parent_Is_Boolean
8968 then
8972 -- Warn on double negation if checking redundant constructs
8974 if Warn_On_Redundant_Constructs
8979 then
8983 -- Complete resolution and evaluation of NOT
8993 -----------------------------
8994 -- Resolve_Operator_Symbol --
8995 -----------------------------
8997 -- Nothing to be done, all resolved already
9003 begin
9007 ----------------------------------
9008 -- Resolve_Qualified_Expression --
9009 ----------------------------------
9017 begin
9020 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9021 -- operation if not needed.
9028 then
9029 Check_SPARK_Restriction
9033 -- A qualified expression requires an exact match of the type, class-
9034 -- wide matching is not allowed. However, if the qualifying type is
9035 -- specific and the expression has a class-wide type, it may still be
9036 -- okay, since it can be the result of the expansion of a call to a
9037 -- dispatching function, so we also have to check class-wideness of the
9038 -- type of the expression's original node.
9041 or else
9045 then
9049 -- If the target type is unconstrained, then we reset the type of the
9050 -- result from the type of the expression. For other cases, the actual
9051 -- subtype of the expression is the target type.
9055 then
9063 ------------------------------
9064 -- Resolve_Raise_Expression --
9065 ------------------------------
9068 begin
9072 else
9077 -------------------
9078 -- Resolve_Range --
9079 -------------------
9086 -- Returns True if N is of the form X'First .. X'Last where X is the
9087 -- same entity for both attributes.
9089 --------------------
9090 -- First_Last_Ref --
9091 --------------------
9097 begin
9102 then
9103 declare
9106 begin
9110 then
9119 -- Start of processing for Resolve_Range
9121 begin
9126 -- Check for inappropriate range on unordered enumeration type
9130 -- Exclude X'First .. X'Last if X is the same entity for both
9132 and then not First_Last_Ref
9133 then
9135 Error_Msg_NE
9142 -- We have to check the bounds for being within the base range as
9143 -- required for a non-static context. Normally this is automatic and
9144 -- done as part of evaluating expressions, but the N_Range node is an
9145 -- exception, since in GNAT we consider this node to be a subexpression,
9146 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9147 -- this, but that would put the test on the main evaluation path for
9148 -- expressions.
9153 -- Check for an ambiguous range over character literals. This will
9154 -- happen with a membership test involving only literals.
9162 -- If bounds are static, constant-fold them, so size computations are
9163 -- identical between front-end and back-end. Do not perform this
9164 -- transformation while analyzing generic units, as type information
9165 -- would be lost when reanalyzing the constant node in the instance.
9178 --------------------------
9179 -- Resolve_Real_Literal --
9180 --------------------------
9185 begin
9186 -- Special processing for fixed-point literals to make sure that the
9187 -- value is an exact multiple of small where this is required. We skip
9188 -- this for the universal real case, and also for generic types.
9194 then
9195 declare
9202 begin
9203 -- Case of literal is not an exact multiple of the Small
9207 -- For a source program literal for a decimal fixed-point type,
9208 -- this is statically illegal (RM 4.9(36)).
9213 then
9217 -- Generate a warning if literal from source
9220 and then Warn_On_Bad_Fixed_Value
9221 then
9222 Error_Msg_N
9224 N);
9227 -- Replace literal by a value that is the exact representation
9228 -- of a value of the type, i.e. a multiple of the small value,
9229 -- by truncation, since Machine_Rounds is false for all GNAT
9230 -- fixed-point types (RM 4.9(38)).
9240 -- In all cases, set the corresponding integer field
9246 -- Now replace the actual type by the expected type as usual
9252 -----------------------
9253 -- Resolve_Reference --
9254 -----------------------
9259 begin
9260 -- Replace general access with specific type
9268 -- If we are taking the reference of a volatile entity, then treat it as
9269 -- a potential modification of this entity. This is too conservative,
9270 -- but necessary because remove side effects can cause transformations
9271 -- of normal assignments into reference sequences that otherwise fail to
9272 -- notice the modification.
9279 --------------------------------
9280 -- Resolve_Selected_Component --
9281 --------------------------------
9296 -- Check whether this is the initialization of a component within an
9297 -- init proc (by assignment or call to another init proc). If true,
9298 -- there is no need for a discriminant check.
9300 --------------------
9301 -- Init_Component --
9302 --------------------
9305 begin
9306 return Inside_Init_Proc
9312 -- Start of processing for Resolve_Selected_Component
9314 begin
9317 -- Use the context type to select the prefix that has a selector
9318 -- of the correct name and type.
9326 else
9330 -- Locate selected component. For a private prefix the selector
9331 -- can denote a discriminant.
9335 -- The visible components of a class-wide type are those of
9336 -- the root type.
9346 then
9353 else
9357 Error_Msg_N
9362 else
9365 -- There may be an implicit dereference. Retrieve
9366 -- designated record type.
9370 else
9376 -- Resolution chooses the new interpretation.
9377 -- Find the component with the right name.
9382 loop
9399 -- There must be a legal interpretation at this point
9406 else
9407 -- Resolve prefix with its type
9412 -- Generate cross-reference. We needed to wait until full overloading
9413 -- resolution was complete to do this, since otherwise we can't tell if
9414 -- we are an lvalue or not.
9418 else
9422 -- If prefix is an access type, the node will be transformed into an
9423 -- explicit dereference during expansion. The type of the node is the
9424 -- designated type of that of the prefix.
9429 else
9433 -- Set flag for expander if discriminant check required
9440 and then not Init_Component
9441 then
9449 -- If the prefix is a record conversion, this may be a renamed
9450 -- discriminant whose bounds differ from those of the original
9451 -- one, so we must ensure that a range check is performed.
9456 then
9460 -- Note: No Eval processing is required, because the prefix is of a
9461 -- record type, or protected type, and neither can possibly be static.
9463 -- If the array type is atomic, and is packed, and we are in a left side
9464 -- context, then this is worth a warning, since we have a situation
9465 -- where the access to the component may cause extra read/writes of the
9466 -- atomic array object, which could be considered unexpected.
9474 then
9475 Error_Msg_N
9477 Error_Msg_N
9484 -------------------
9485 -- Resolve_Shift --
9486 -------------------
9493 begin
9494 -- We do the resolution using the base type, because intermediate values
9495 -- in expressions always are of the base type, not a subtype of it.
9508 ---------------------------
9509 -- Resolve_Short_Circuit --
9510 ---------------------------
9517 begin
9518 -- Ensure all actions associated with the left operand (e.g.
9519 -- finalization of transient controlled objects) are fully evaluated
9520 -- locally within an expression with actions. This is particularly
9521 -- helpful for coverage analysis. However this should not happen in
9522 -- generics.
9525 declare
9527 begin
9535 -- Set Comes_From_Source on L to preserve warnings for unset
9536 -- reference.
9545 -- Check for issuing warning for always False assert/check, this happens
9546 -- when assertions are turned off, in which case the pragma Assert/Check
9547 -- was transformed into:
9549 -- if False and then <condition> then ...
9551 -- and we detect this pattern
9553 if Warn_On_Assertion_Failure
9560 then
9561 declare
9564 begin
9565 -- Special handling of Asssert pragma
9569 then
9570 declare
9572 Original_Node
9573 (Expression
9576 begin
9577 -- Don't warn if original condition is explicit False,
9578 -- since obviously the failure is expected in this case.
9582 then
9585 -- Issue warning. We do not want the deletion of the
9586 -- IF/AND-THEN to take this message with it. We achieve this
9587 -- by making sure that the expanded code points to the Sloc
9588 -- of the expression, not the original pragma.
9590 else
9591 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
9592 -- The source location of the expression is not usually
9593 -- the best choice here. For example, it gets located on
9594 -- the last AND keyword in a chain of boolean expressiond
9595 -- AND'ed together. It is best to put the message on the
9596 -- first character of the assertion, which is the effect
9597 -- of the First_Node call here.
9599 Error_Msg_F
9601 Expression
9606 -- Similar processing for Check pragma
9610 then
9611 -- Don't want to warn if original condition is explicit False
9613 declare
9615 Original_Node
9616 (Expression
9618 begin
9621 then
9624 -- Post warning
9626 else
9627 -- Again use Error_Msg_F rather than Error_Msg_N, see
9628 -- comment above for an explanation of why we do this.
9630 Error_Msg_F
9632 Expression
9640 -- Continue with processing of short circuit
9649 -------------------
9650 -- Resolve_Slice --
9651 -------------------
9660 begin
9663 -- Use the context type to select the prefix that yields the correct
9664 -- array type.
9666 declare
9673 begin
9681 then
9689 else
9694 else
9705 else
9715 -- If the prefix is an access to an unconstrained array, we must use
9716 -- the actual subtype of the object to perform the index checks. The
9717 -- object denoted by the prefix is implicit in the node, so we build
9718 -- an explicit representation for it in order to compute the actual
9719 -- subtype.
9724 declare
9728 begin
9739 then
9742 -- If the name is a selected component that depends on discriminants,
9743 -- build an actual subtype for it. This can happen only when the name
9744 -- itself is overloaded; otherwise the actual subtype is created when
9745 -- the selected component is analyzed.
9748 and then Full_Analysis
9750 then
9751 declare
9754 begin
9759 -- Maybe this should just be "else", instead of checking for the
9760 -- specific case of slice??? This is needed for the case where the
9761 -- prefix is an Image attribute, which gets expanded to a slice, and so
9762 -- has a constrained subtype which we want to use for the slice range
9763 -- check applied below (the range check won't get done if the
9764 -- unconstrained subtype of the 'Image is used).
9770 -- Obtain the type of the array index
9774 else
9778 -- If name was overloaded, set slice type correctly now
9782 -- Handle the generation of a range check that compares the array index
9783 -- against the discrete_range. The check is not applied to internally
9784 -- built nodes associated with the expansion of dispatch tables. Check
9785 -- that Ada.Tags has already been loaded to avoid extra dependencies on
9786 -- the unit.
9788 if Tagged_Type_Expansion
9794 then
9797 -- The discrete_range is specified by a subtype indication. Create a
9798 -- shallow copy and inherit the type, parent and source location from
9799 -- the discrete_range. This ensures that the range check is inserted
9800 -- relative to the slice and that the runtime exception points to the
9801 -- proper construct.
9810 -- The discrete_range is a regular range. Resolve the bounds and remove
9811 -- their side effects.
9813 else
9830 -- Check bad use of type with predicates
9832 declare
9835 begin
9838 then
9840 else
9845 Bad_Predicated_Subtype_Use
9850 -- Otherwise here is where we check suspicious indexes
9861 ----------------------------
9862 -- Resolve_String_Literal --
9863 ----------------------------
9874 begin
9875 -- For a string appearing in a concatenation, defer creation of the
9876 -- string_literal_subtype until the end of the resolution of the
9877 -- concatenation, because the literal may be constant-folded away. This
9878 -- is a useful optimization for long concatenation expressions.
9880 -- If the string is an aggregate built for a single character (which
9881 -- happens in a non-static context) or a is null string to which special
9882 -- checks may apply, we build the subtype. Wide strings must also get a
9883 -- string subtype if they come from a one character aggregate. Strings
9884 -- generated by attributes might be static, but it is often hard to
9885 -- determine whether the enclosing context is static, so we generate
9886 -- subtypes for them as well, thus losing some rarer optimizations ???
9887 -- Same for strings that come from a static conversion.
9889 Need_Check :=
9898 -- If the resolving type is itself a string literal subtype, we can just
9899 -- reuse it, since there is no point in creating another.
9905 and then not Need_Check
9907 N_Attribute_Reference,
9908 N_Qualified_Expression,
9909 N_Type_Conversion)
9910 then
9913 -- Otherwise we must create a string literal subtype. Note that the
9914 -- whole idea of string literal subtypes is simply to avoid the need
9915 -- for building a full fledged array subtype for each literal.
9917 else
9923 or else Need_Check
9924 then
9931 then
9937 -- The validity of a null string has been checked in the call to
9938 -- Eval_String_Literal.
9943 -- Always accept string literal with component type Any_Character, which
9944 -- occurs in error situations and in comparisons of literals, both of
9945 -- which should accept all literals.
9950 -- If the type is bit-packed, then we always transform the string
9951 -- literal into a full fledged aggregate.
9956 -- Deal with cases of Wide_Wide_String, Wide_String, and String
9958 else
9959 -- For Standard.Wide_Wide_String, or any other type whose component
9960 -- type is Standard.Wide_Wide_Character, we know that all the
9961 -- characters in the string must be acceptable, since the parser
9962 -- accepted the characters as valid character literals.
9967 -- For the case of Standard.String, or any other type whose component
9968 -- type is Standard.Character, we must make sure that there are no
9969 -- wide characters in the string, i.e. that it is entirely composed
9970 -- of characters in range of type Character.
9972 -- If the string literal is the result of a static concatenation, the
9973 -- test has already been performed on the components, and need not be
9974 -- repeated.
9978 then
9982 -- If we are out of range, post error. This is one of the
9983 -- very few places that we place the flag in the middle of
9984 -- a token, right under the offending wide character. Not
9985 -- quite clear if this is right wrt wide character encoding
9986 -- sequences, but it's only an error message.
9988 Error_Msg
9995 -- For the case of Standard.Wide_String, or any other type whose
9996 -- component type is Standard.Wide_Character, we must make sure that
9997 -- there are no wide characters in the string, i.e. that it is
9998 -- entirely composed of characters in range of type Wide_Character.
10000 -- If the string literal is the result of a static concatenation,
10001 -- the test has already been performed on the components, and need
10002 -- not be repeated.
10006 then
10010 -- If we are out of range, post error. This is one of the
10011 -- very few places that we place the flag in the middle of
10012 -- a token, right under the offending wide character.
10014 -- This is not quite right, because characters in general
10015 -- will take more than one character position ???
10017 Error_Msg
10024 -- If the root type is not a standard character, then we will convert
10025 -- the string into an aggregate and will let the aggregate code do
10026 -- the checking. Standard Wide_Wide_Character is also OK here.
10028 else
10032 -- See if the component type of the array corresponding to the string
10033 -- has compile time known bounds. If yes we can directly check
10034 -- whether the evaluation of the string will raise constraint error.
10035 -- Otherwise we need to transform the string literal into the
10036 -- corresponding character aggregate and let the aggregate code do
10037 -- the checking.
10041 -- Check for the case of full range, where we are definitely OK
10047 -- Here the range is not the complete base type range, so check
10049 declare
10057 begin
10060 then
10066 then
10067 Apply_Compile_Time_Constraint_Error
10069 CE_Range_Check_Failed,
10080 -- If we got here we meed to transform the string literal into the
10081 -- equivalent qualified positional array aggregate. This is rather
10082 -- heavy artillery for this situation, but it is hard work to avoid.
10084 declare
10089 begin
10090 -- Build the character literals, we give them source locations that
10091 -- correspond to the string positions, which is a bit tricky given
10092 -- the possible presence of wide character escape sequences.
10106 -- Should we have a call to Skip_Wide here ???
10108 -- ??? else
10109 -- Skip_Wide (P);
10117 Expression =>
10124 -----------------------------
10125 -- Resolve_Type_Conversion --
10126 -----------------------------
10138 -- Set to False to suppress cases where we want to suppress the test
10139 -- for redundancy to avoid possible false positives on this warning.
10141 begin
10142 if not Conv_OK
10144 then
10148 -- If the Operand Etype is Universal_Fixed, then the conversion is
10149 -- never redundant. We need this check because by the time we have
10150 -- finished the rather complex transformation, the conversion looks
10151 -- redundant when it is not.
10156 -- If the operand is marked as Any_Fixed, then special processing is
10157 -- required. This is also a case where we suppress the test for a
10158 -- redundant conversion, since most certainly it is not redundant.
10163 -- Mixed-mode operation involving a literal. Context must be a fixed
10164 -- type which is applied to the literal subsequently.
10172 or else
10174 then
10175 -- Return if expression is ambiguous
10180 -- If nothing else, the available fixed type is Duration
10182 else
10186 -- Resolve the real operand with largest available precision
10190 else
10196 -- If the operand is a literal (it could be a non-static and
10197 -- illegal exponentiation) check whether the use of Duration
10198 -- is potentially inaccurate.
10203 then
10204 Error_Msg_N
10207 Error_Msg_N
10214 then
10217 else
10226 -- In SPARK, a type conversion between array types should be restricted
10227 -- to types which have matching static bounds.
10229 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10230 -- operation if not needed.
10237 then
10238 Check_SPARK_Restriction
10242 -- In formal mode, the operand of an ancestor type conversion must be an
10243 -- object (not an expression).
10251 then
10257 -- Note: we do the Eval_Type_Conversion call before applying the
10258 -- required checks for a subtype conversion. This is important, since
10259 -- both are prepared under certain circumstances to change the type
10260 -- conversion to a constraint error node, but in the case of
10261 -- Eval_Type_Conversion this may reflect an illegality in the static
10262 -- case, and we would miss the illegality (getting only a warning
10263 -- message), if we applied the type conversion checks first.
10267 -- Even when evaluation is not possible, we may be able to simplify the
10268 -- conversion or its expression. This needs to be done before applying
10269 -- checks, since otherwise the checks may use the original expression
10270 -- and defeat the simplifications. This is specifically the case for
10271 -- elimination of the floating-point Truncation attribute in
10272 -- float-to-int conversions.
10276 -- If after evaluation we still have a type conversion, then we may need
10277 -- to apply checks required for a subtype conversion.
10279 -- Skip these type conversion checks if universal fixed operands
10280 -- operands involved, since range checks are handled separately for
10281 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10287 then
10291 -- Issue warning for conversion of simple object to its own type. We
10292 -- have to test the original nodes, since they may have been rewritten
10293 -- by various optimizations.
10297 -- Here we test for a redundant conversion if the warning mode is
10298 -- active (and was not locally reset), and we have a type conversion
10299 -- from source not appearing in a generic instance.
10301 if Test_Redundant
10304 and then not In_Instance
10305 then
10309 -- If the node is part of a larger expression, the Target_Type
10310 -- may not be the original type of the node if the context is a
10311 -- condition. Recover original type to see if conversion is needed.
10315 then
10319 -- If we have an entity name, then give the warning if the entity
10320 -- is the right type, or if it is a loop parameter covered by the
10321 -- original type (that's needed because loop parameters have an
10322 -- odd subtype coming from the bounds).
10325 and then
10327 or else
10331 -- If not an entity, then type of expression must match
10334 then
10335 -- One more check, do not give warning if the analyzed conversion
10336 -- has an expression with non-static bounds, and the bounds of the
10337 -- target are static. This avoids junk warnings in cases where the
10338 -- conversion is necessary to establish staticness, for example in
10339 -- a case statement.
10343 then
10346 -- Finally, if this type conversion occurs in a context requiring
10347 -- a prefix, and the expression is a qualified expression then the
10348 -- type conversion is not redundant, since a qualified expression
10349 -- is not a prefix, whereas a type conversion is. For example, "X
10350 -- := T'(Funx(...)).Y;" is illegal because a selected component
10351 -- requires a prefix, but a type conversion makes it legal: "X :=
10352 -- T(T'(Funx(...))).Y;"
10354 -- In Ada 2012, a qualified expression is a name, so this idiom is
10355 -- no longer needed, but we still suppress the warning because it
10356 -- seems unfriendly for warnings to pop up when you switch to the
10357 -- newer language version.
10361 N_Indexed_Component,
10362 N_Selected_Component,
10363 N_Slice,
10364 N_Explicit_Dereference)
10365 then
10368 -- Never warn on conversion to Long_Long_Integer'Base since
10369 -- that is most likely an artifact of the extended overflow
10370 -- checking and comes from complex expanded code.
10375 -- Here we give the redundant conversion warning. If it is an
10376 -- entity, give the name of the entity in the message. If not,
10377 -- just mention the expression.
10379 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10381 else
10384 Error_Msg_NE -- CODEFIX
10387 else
10388 Error_Msg_NE
10396 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10397 -- No need to perform any interface conversion if the type of the
10398 -- expression coincides with the target type.
10401 and then Expander_Active
10403 then
10404 declare
10408 begin
10409 -- If the type of the operand is a limited view, use the non-
10410 -- limited view when available.
10415 then
10431 -- Conversion from interface type
10435 -- Ada 2005 (AI-217): Handle entities from limited views
10439 Error_Msg_NE -- CODEFIX
10442 Error_Msg_N
10444 N);
10447 and then not
10450 then
10452 Error_Msg_NE -- CODEFIX
10455 Error_Msg_N
10457 N);
10459 else
10463 -- Conversion to interface type
10467 -- Handle subtypes
10474 or else Interface_Present_In_Ancestor
10477 then
10479 else
10482 Error_Msg_N
10490 -- Ada 2012: if target type has predicates, the result requires a
10491 -- predicate check. If the context is a call to another predicate
10492 -- check we must prevent infinite recursion.
10498 or else
10500 then
10503 else
10509 ----------------------
10510 -- Resolve_Unary_Op --
10511 ----------------------
10520 begin
10523 Check_SPARK_Restriction
10527 -- Deal with intrinsic unary operators
10533 then
10538 -- Deal with universal cases
10541 or else
10543 then
10550 -- Generate warning for expressions like abs (x mod 2)
10552 if Warn_On_Redundant_Constructs
10554 then
10558 Error_Msg_N -- CODEFIX
10563 -- Deal with reference generation
10570 -- Set overflow checking bit. Much cleverer code needed here eventually
10571 -- and perhaps the Resolve routines should be separated for the various
10572 -- arithmetic operations, since they will need different processing ???
10580 -- Generate warning for expressions like -5 mod 3 for integers. No need
10581 -- to worry in the floating-point case, since parens do not affect the
10582 -- result so there is no point in giving in a warning.
10584 declare
10593 begin
10594 if Warn_On_Questionable_Missing_Parens
10598 then
10601 -- We are looking for cases where the right operand is not
10602 -- parenthesized, and is a binary operator, multiply, divide, or
10603 -- mod. These are the cases where the grouping can affect results.
10607 then
10608 -- For mod, we always give the warning, since the value is
10609 -- affected by the parenthesization (e.g. (-5) mod 315 /=
10610 -- -(5 mod 315)). But for the other cases, the only concern is
10611 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
10612 -- overflows, but (-2) * 64 does not). So we try to give the
10613 -- message only when overflow is possible.
10617 then
10622 else
10628 else
10632 -- Note that the test below is deliberately excluding the
10633 -- largest negative number, since that is a potentially
10634 -- troublesome case (e.g. -2 * x, where the result is the
10635 -- largest negative integer has an overflow with 2 * x).
10642 -- For the multiplication case, the only case we have to worry
10643 -- about is when (-a)*b is exactly the largest negative number
10644 -- so that -(a*b) can cause overflow. This can only happen if
10645 -- a is a power of 2, and more generally if any operand is a
10646 -- constant that is not a power of 2, then the parentheses
10647 -- cannot affect whether overflow occurs. We only bother to
10648 -- test the left most operand
10650 -- Loop looking at left operands for one that has known value
10657 -- Operand value of 0 or 1 skips warning
10662 -- Otherwise check power of 2, if power of 2, warn, if
10663 -- anything else, skip warning.
10665 else
10669 else
10678 -- Keep looking at left operands
10683 -- For rem or "/" we can only have a problematic situation
10684 -- if the divisor has a value of minus one or one. Otherwise
10685 -- overflow is impossible (divisor > 1) or we have a case of
10686 -- division by zero in any case.
10691 then
10695 -- If we fall through warning should be issued
10697 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
10699 Error_Msg_N
10706 ----------------------------------
10707 -- Resolve_Unchecked_Expression --
10708 ----------------------------------
10710 procedure Resolve_Unchecked_Expression
10713 is
10714 begin
10719 ---------------------------------------
10720 -- Resolve_Unchecked_Type_Conversion --
10721 ---------------------------------------
10723 procedure Resolve_Unchecked_Type_Conversion
10726 is
10732 begin
10733 -- Resolve operand using its own type
10737 -- In an inlined context, the unchecked conversion may be applied
10738 -- to a literal, in which case its type is the type of the context.
10739 -- (In other contexts conversions cannot apply to literals).
10741 if In_Inlined_Body
10745 then
10753 ------------------------------
10754 -- Rewrite_Operator_As_Call --
10755 ------------------------------
10762 begin
10769 New_N :=
10780 ------------------------------
10781 -- Rewrite_Renamed_Operator --
10782 ------------------------------
10784 procedure Rewrite_Renamed_Operator
10788 is
10793 begin
10794 -- Do not perform this transformation within a pre/postcondition,
10795 -- because the expression will be re-analyzed, and the transformation
10796 -- might affect the visibility of the operator, e.g. in an instance.
10802 -- Rewrite the operator node using the real operator, not its renaming.
10803 -- Exclude user-defined intrinsic operations of the same name, which are
10804 -- treated separately and rewritten as calls.
10813 -- Indicate that both the original entity and its renaming are
10814 -- referenced at this point.
10825 -- If the context type is private, add the appropriate conversions so
10826 -- that the operator is applied to the full view. This is done in the
10827 -- routines that resolve intrinsic operators.
10831 then
10833 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
10834 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
10847 -- Operator renames a user-defined operator of the same name. Use the
10848 -- original operator in the node, which is the one Gigi knows about.
10855 -----------------------
10856 -- Set_Slice_Subtype --
10857 -----------------------
10859 -- Build an implicit subtype declaration to represent the type delivered by
10860 -- the slice. This is an abbreviated version of an array subtype. We define
10861 -- an index subtype for the slice, using either the subtype name or the
10862 -- discrete range of the slice. To be consistent with index usage elsewhere
10863 -- we create a list header to hold the single index. This list is not
10864 -- otherwise attached to the syntax tree.
10875 begin
10881 else
10882 -- We force the evaluation of a range. This is definitely needed in
10883 -- the renamed case, and seems safer to do unconditionally. Note in
10884 -- any case that since we will create and insert an Itype referring
10885 -- to this range, we must make sure any side effect removal actions
10886 -- are inserted before the Itype definition.
10892 -- If the discrete range is given by a subtype indication, the
10893 -- type of the slice is the base of the subtype mark.
10896 declare
10898 begin
10907 -- Take a new copy of Drange (where bounds have been rewritten to
10908 -- reference side-effect-free names). Using a separate tree ensures
10909 -- that further expansion (e.g. while rewriting a slice assignment
10910 -- into a FOR loop) does not attempt to remove side effects on the
10911 -- bounds again (which would cause the bounds in the index subtype
10912 -- definition to refer to temporaries before they are defined) (the
10913 -- reason is that some names are considered side effect free here
10914 -- for the subtype, but not in the context of a loop iteration
10915 -- scheme).
10936 -- The Etype of the existing Slice node is reset to this slice subtype.
10937 -- Its bounds are obtained from its first index.
10941 -- For packed slice subtypes, freeze immediately (except in the case of
10942 -- being in a "spec expression" where we never freeze when we first see
10943 -- the expression).
10948 -- For all other cases insert an itype reference in the slice's actions
10949 -- so that the itype is frozen at the proper place in the tree (i.e. at
10950 -- the point where actions for the slice are analyzed). Note that this
10951 -- is different from freezing the itype immediately, which might be
10952 -- premature (e.g. if the slice is within a transient scope). This needs
10953 -- to be done only if expansion is enabled.
10960 --------------------------------
10961 -- Set_String_Literal_Subtype --
10962 --------------------------------
10970 begin
10982 -- The low bound is set from the low bound of the corresponding index
10983 -- type. Note that we do not store the high bound in the string literal
10984 -- subtype, but it can be deduced if necessary from the length and the
10985 -- low bound.
10990 -- If the lower bound is not static we create a range for the string
10991 -- literal, using the index type and the known length of the literal.
10992 -- The index type is not necessarily Positive, so the upper bound is
10993 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
10995 else
10996 declare
11002 Prefix =>
11006 Left_Opnd =>
11009 Prefix =>
11011 Expressions =>
11013 Right_Opnd =>
11022 begin
11024 Set_String_Literal_Low_Bound
11027 else
11028 -- If the index type is an enumeration type, build bounds
11029 -- expression with attributes.
11031 Set_String_Literal_Low_Bound
11035 Prefix =>
11042 -- Build bona fide subtype for the string, and wrap it in an
11043 -- unchecked conversion, because the backend expects the
11044 -- String_Literal_Subtype to have a static lower bound.
11046 Index_Subtype :=
11053 -- In the context, the Index_Type may already have a constraint,
11054 -- so use common base type on string subtype. The base type may
11055 -- be used when generating attributes of the string, for example
11056 -- in the context of a slice assignment.
11081 ------------------------------
11082 -- Simplify_Type_Conversion --
11083 ------------------------------
11086 begin
11088 declare
11093 begin
11094 -- Special processing if the conversion is the expression of a
11095 -- Rounding or Truncation attribute reference. In this case we
11096 -- replace:
11098 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11100 -- by
11102 -- ityp (x)
11104 -- with the Float_Truncate flag set to False or True respectively,
11105 -- which is more efficient.
11108 and then
11114 Name_Truncation)
11115 then
11116 declare
11119 begin
11129 -----------------------------
11130 -- Unique_Fixed_Point_Type --
11131 -----------------------------
11140 -- Give error messages for true ambiguity. Messages are posted on node
11141 -- N, and entities T1, T2 are the possible interpretations.
11143 -----------------------
11144 -- Fixed_Point_Error --
11145 -----------------------
11148 begin
11154 -- Start of processing for Unique_Fixed_Point_Type
11156 begin
11157 -- The operations on Duration are visible, so Duration is always a
11158 -- possible interpretation.
11162 -- Look for fixed-point types in enclosing scopes
11171 then
11173 Fixed_Point_Error;
11175 else
11186 -- Look for visible fixed type declarations in the context
11197 then
11199 Fixed_Point_Error;
11201 else
11214 Error_Msg_NE
11216 else
11217 Error_Msg_NE
11224 ----------------------
11225 -- Valid_Conversion --
11226 ----------------------
11228 function Valid_Conversion
11233 is
11238 function Conversion_Check
11241 -- Little routine to post Msg if Valid is False, returns Valid value
11244 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11246 procedure Conversion_Error_NE
11250 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11252 function Valid_Tagged_Conversion
11255 -- Specifically test for validity of tagged conversions
11258 -- Check index and component conformance, and accessibility levels if
11259 -- the component types are anonymous access types (Ada 2005).
11261 ----------------------
11262 -- Conversion_Check --
11263 ----------------------
11265 function Conversion_Check
11268 is
11269 begin
11270 if not Valid
11272 -- A generic unit has already been analyzed and we have verified
11273 -- that a particular conversion is OK in that context. Since the
11274 -- instance is reanalyzed without relying on the relationships
11275 -- established during the analysis of the generic, it is possible
11276 -- to end up with inconsistent views of private types. Do not emit
11277 -- the error message in such cases. The rest of the machinery in
11278 -- Valid_Conversion still ensures the proper compatibility of
11279 -- target and operand types.
11281 and then not In_Instance
11282 then
11289 ------------------------
11290 -- Conversion_Error_N --
11291 ------------------------
11294 begin
11300 -------------------------
11301 -- Conversion_Error_NE --
11302 -------------------------
11304 procedure Conversion_Error_NE
11308 is
11309 begin
11315 ----------------------------
11316 -- Valid_Array_Conversion --
11317 ----------------------------
11320 is
11335 begin
11336 -- Error if wrong number of dimensions
11338 if
11340 then
11341 Conversion_Error_N
11345 -- Number of dimensions matches
11347 else
11348 -- Loop through indexes of the two arrays
11356 -- Error if index types are incompatible
11362 then
11363 Conversion_Error_N
11365 Operand);
11373 -- If component types have same base type, all set
11378 -- Here if base types of components are not the same. The only
11379 -- time this is allowed is if we have anonymous access types.
11381 -- The conversion of arrays of anonymous access types can lead
11382 -- to dangling pointers. AI-392 formalizes the accessibility
11383 -- checks that must be applied to such conversions to prevent
11384 -- out-of-scope references.
11386 elsif Ekind_In
11388 E_Anonymous_Access_Subprogram_Type)
11390 and then
11392 then
11395 then
11398 Conversion_Error_N
11408 -- Conversion not allowed because of accessibility levels
11410 else
11411 Conversion_Error_N
11417 else
11421 -- All other cases where component base types do not match
11423 else
11424 Conversion_Error_N
11426 Operand);
11430 -- Check that component subtypes statically match. For numeric
11431 -- types this means that both must be either constrained or
11432 -- unconstrained. For enumeration types the bounds must match.
11433 -- All of this is checked in Subtypes_Statically_Match.
11435 if not Subtypes_Statically_Match
11437 then
11438 Conversion_Error_N
11447 -----------------------------
11448 -- Valid_Tagged_Conversion --
11449 -----------------------------
11451 function Valid_Tagged_Conversion
11454 is
11455 begin
11456 -- Upward conversions are allowed (RM 4.6(22))
11460 then
11463 -- Downward conversion are allowed if the operand is class-wide
11464 -- (RM 4.6(23)).
11468 then
11473 then
11474 return
11478 -- Ada 2005 (AI-251): The conversion to/from interface types is
11479 -- always valid
11484 -- If the operand is a class-wide type obtained through a limited_
11485 -- with clause, and the context includes the non-limited view, use
11486 -- it to determine whether the conversion is legal.
11492 then
11497 then
11500 else
11501 Conversion_Error_NE
11508 -- Start of processing for Valid_Conversion
11510 begin
11514 declare
11522 begin
11523 -- Remove procedure calls, which syntactically cannot appear in
11524 -- this context, but which cannot be removed by type checking,
11525 -- because the context does not impose a type.
11527 -- The node may be labelled overloaded, but still contain only one
11528 -- interpretation because others were discarded earlier. If this
11529 -- is the case, retain the single interpretation if legal.
11537 then
11538 -- More than one candidate interpretation is available
11546 -- When compiling for a system where Address is of a visible
11547 -- integer type, spurious ambiguities can be produced when
11548 -- arithmetic operations have a literal operand and return
11549 -- System.Address or a descendant of it. These ambiguities
11550 -- are usually resolved by the context, but for conversions
11551 -- there is no context type and the removal of the spurious
11552 -- operations must be done explicitly here.
11554 if not Address_Is_Private
11556 then
11581 Conversion_Error_N
11584 -- If the interpretation involves a standard operator, use
11585 -- the location of the type, which may be user-defined.
11589 else
11593 Conversion_Error_N -- CODEFIX
11598 else
11602 Conversion_Error_N -- CODEFIX
11614 -- Deal with conversion of integer type to address if the pragma
11615 -- Allow_Integer_Address is in effect. We convert the conversion to
11616 -- an unchecked conversion in this case and we are all done.
11624 -- If we are within a child unit, check whether the type of the
11625 -- expression has an ancestor in a parent unit, in which case it
11626 -- belongs to its derivation class even if the ancestor is private.
11627 -- See RM 7.3.1 (5.2/3).
11631 -- Numeric types
11635 -- A universal fixed expression can be converted to any numeric type
11640 -- Also no need to check when in an instance or inlined body, because
11641 -- the legality has been established when the template was analyzed.
11642 -- Furthermore, numeric conversions may occur where only a private
11643 -- view of the operand type is visible at the instantiation point.
11644 -- This results in a spurious error if we check that the operand type
11645 -- is a numeric type.
11647 -- Note: in a previous version of this unit, the following tests were
11648 -- applied only for generated code (Comes_From_Source set to False),
11649 -- but in fact the test is required for source code as well, since
11650 -- this situation can arise in source code.
11655 -- Otherwise we need the conversion check
11657 else
11658 return Conversion_Check
11660 or else
11666 -- Array types
11672 then
11673 Conversion_Error_N
11677 else
11681 -- Ada 2005 (AI-251): Anonymous access types where target references an
11682 -- interface type.
11685 E_Anonymous_Access_Type)
11687 then
11688 -- Check the static accessibility rule of 4.6(17). Note that the
11689 -- check is not enforced when within an instance body, since the
11690 -- RM requires such cases to be caught at run time.
11692 -- If the operand is a rewriting of an allocator no check is needed
11693 -- because there are no accessibility issues.
11701 then
11702 -- In an instance, this is a run-time check, but one we know
11703 -- will fail, so generate an appropriate warning. The raise
11704 -- will be generated by Expand_N_Type_Conversion.
11708 Conversion_Error_N
11710 Operand);
11713 else
11714 Conversion_Error_N
11716 Operand);
11720 -- Special accessibility checks are needed in the case of access
11721 -- discriminants declared for a limited type.
11725 then
11726 -- When the operand is a selected access discriminant the check
11727 -- needs to be made against the level of the object denoted by
11728 -- the prefix of the selected name (Object_Access_Level handles
11729 -- checking the prefix of the operand for this case).
11734 then
11735 -- In an instance, this is a run-time check, but one we know
11736 -- will fail, so generate an appropriate warning. The raise
11737 -- will be generated by Expand_N_Type_Conversion.
11741 Conversion_Error_N
11746 -- Real error if not in instance body
11748 else
11749 Conversion_Error_N
11756 -- The case of a reference to an access discriminant from
11757 -- within a limited type declaration (which will appear as
11758 -- a discriminal) is always illegal because the level of the
11759 -- discriminant is considered to be deeper than any (nameable)
11760 -- access type.
11764 and then
11767 then
11768 Conversion_Error_N
11770 Operand);
11778 -- General and anonymous access types
11781 E_Anonymous_Access_Type)
11782 and then
11783 Conversion_Check
11785 and then not
11787 E_Access_Protected_Subprogram_Type),
11789 then
11792 then
11793 Conversion_Error_N
11798 -- Check the static accessibility rule of 4.6(17). Note that the
11799 -- check is not enforced when within an instance body, since the RM
11800 -- requires such cases to be caught at run time.
11805 N_Object_Declaration
11806 then
11807 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
11808 -- conversions from an anonymous access type to a named general
11809 -- access type. Such conversions are not allowed in the case of
11810 -- access parameters and stand-alone objects of an anonymous
11811 -- access type. The implicit conversion case is recognized by
11812 -- testing that Comes_From_Source is False and that it's been
11813 -- rewritten. The Comes_From_Source test isn't sufficient because
11814 -- nodes in inlined calls to predefined library routines can have
11815 -- Comes_From_Source set to False. (Is there a better way to test
11816 -- for implicit conversions???)
11823 then
11826 -- Implicit conversions aren't allowed for objects of an
11827 -- anonymous access type, since such objects have nonstatic
11828 -- levels in Ada 2012.
11831 N_Object_Declaration
11832 then
11833 Conversion_Error_N
11838 -- Implicit conversions aren't allowed for anonymous access
11839 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
11840 -- is done to exclude anonymous access results.
11844 N_Function_Specification,
11845 N_Procedure_Specification)
11846 then
11847 Conversion_Error_N
11852 -- This is a case where there's an enclosing object whose
11853 -- to which the "statically deeper than" relationship does
11854 -- not apply (such as an access discriminant selected from
11855 -- a dereference of an access parameter).
11859 then
11860 Conversion_Error_N
11865 -- In other cases, the level of the operand's type must be
11866 -- statically less deep than that of the target type, else
11867 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
11871 then
11872 Conversion_Error_N
11881 then
11882 -- In an instance, this is a run-time check, but one we know
11883 -- will fail, so generate an appropriate warning. The raise
11884 -- will be generated by Expand_N_Type_Conversion.
11888 Conversion_Error_N
11890 Operand);
11893 -- If not in an instance body, this is a real error
11895 else
11896 -- Avoid generation of spurious error message
11899 Conversion_Error_N
11901 Operand);
11907 -- Special accessibility checks are needed in the case of access
11908 -- discriminants declared for a limited type.
11912 then
11913 -- When the operand is a selected access discriminant the check
11914 -- needs to be made against the level of the object denoted by
11915 -- the prefix of the selected name (Object_Access_Level handles
11916 -- checking the prefix of the operand for this case).
11921 then
11922 -- In an instance, this is a run-time check, but one we know
11923 -- will fail, so generate an appropriate warning. The raise
11924 -- will be generated by Expand_N_Type_Conversion.
11928 Conversion_Error_N
11933 -- If not in an instance body, this is a real error
11935 else
11936 Conversion_Error_N
11943 -- The case of a reference to an access discriminant from
11944 -- within a limited type declaration (which will appear as
11945 -- a discriminal) is always illegal because the level of the
11946 -- discriminant is considered to be deeper than any (nameable)
11947 -- access type.
11950 and then
11953 then
11954 Conversion_Error_N
11956 Operand);
11962 -- In the presence of limited_with clauses we have to use non-limited
11963 -- views, if available.
11967 -- Helper function to handle limited views
11969 --------------------------
11970 -- Full_Designated_Type --
11971 --------------------------
11976 begin
11977 -- Handle the limited view of a type
11982 then
11984 else
11989 -- Local Declarations
11997 -- Start of processing for Check_Limited
11999 begin
12003 else
12005 Conversion_Error_NE
12010 -- Ada 2005 AI-384: legality rule is symmetric in both
12011 -- designated types. The conversion is legal (with possible
12012 -- constraint check) if either designated type is
12013 -- unconstrained.
12016 or else
12018 and then
12021 then
12022 -- Special case, if Value_Size has been used to make the
12023 -- sizes different, the conversion is not allowed even
12024 -- though the subtypes statically match.
12029 then
12030 Conversion_Error_NE
12033 Conversion_Error_NE
12038 -- Normal case where conversion is allowed
12040 else
12044 else
12045 Error_Msg_NE
12053 -- Access to subprogram types. If the operand is an access parameter,
12054 -- the type has a deeper accessibility that any master, and cannot be
12055 -- assigned. We must make an exception if the conversion is part of an
12056 -- assignment and the target is the return object of an extended return
12057 -- statement, because in that case the accessibility check takes place
12058 -- after the return.
12062 -- Note: this test of Opnd_Type is there to prevent entering this
12063 -- branch in the case of a remote access to subprogram type, which
12064 -- is internally represented as an E_Record_Type.
12067 then
12071 and then
12075 then
12076 Conversion_Error_N
12078 Operand);
12079 Conversion_Error_N
12082 Operand);
12084 Error_Msg_NE
12089 -- Check that the designated types are subtype conformant
12095 -- Check the static accessibility rule of 4.6(20)
12099 then
12100 Conversion_Error_N
12102 Operand);
12104 -- Check that if the operand type is declared in a generic body,
12105 -- then the target type must be declared within that same body
12106 -- (enforces last sentence of 4.6(20)).
12109 declare
12115 begin
12122 Conversion_Error_N
12131 -- Remote access to subprogram types
12135 then
12136 -- It is valid to convert from one RAS type to another provided
12137 -- that their specification statically match.
12139 -- Note: at this point, remote access to subprogram types have been
12140 -- expanded to their E_Record_Type representation, and we need to
12141 -- go back to the original access type definition using the
12142 -- Corresponding_Remote_Type attribute in order to check that the
12143 -- designated profiles match.
12148 Check_Subtype_Conformant
12151 Old_Id =>
12153 Err_Loc =>
12154 N);
12157 -- If it was legal in the generic, it's legal in the instance
12162 -- If both are tagged types, check legality of view conversions
12165 and then
12167 then
12170 -- Types derived from the same root type are convertible
12175 -- In an instance or an inlined body, there may be inconsistent views of
12176 -- the same type, or of types derived from a common root.
12179 and then
12182 then
12185 -- Special check for common access type error case
12189 then
12191 Conversion_Error_NE -- CODEFIX
12195 -- Here we have a real conversion error
12197 else
12198 Conversion_Error_NE