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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) 1992-2015, 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 ------------------------------------------------------------------------------
87 -----------------------
88 -- Local Subprograms --
89 -----------------------
91 -- Second pass (top-down) type checking and overload resolution procedures
92 -- Typ is the type required by context. These procedures propagate the
93 -- type information recursively to the descendants of N. If the node is not
94 -- overloaded, its Etype is established in the first pass. If overloaded,
95 -- the Resolve routines set the correct type. For arithmetic operators, the
96 -- Etype is the base type of the context.
98 -- Note that Resolve_Attribute is separated off in Sem_Attr
101 -- Enforce the restrictions on the use of discriminants when constraining
102 -- a component of a discriminated type (record or concurrent type).
105 -- Given a node for an operator associated with type T, check that the
106 -- operator is visible. Operators all of whose operands are universal must
107 -- be checked for visibility during resolution because their type is not
108 -- determinable based on their operands.
110 procedure Check_Fully_Declared_Prefix
113 -- Check that the type of the prefix of a dereference is not incomplete
116 -- Given a call node, N, which is known to occur immediately within the
117 -- subprogram being called, determines whether it is a detectable case of
118 -- an infinite recursion, and if so, outputs appropriate messages. Returns
119 -- True if an infinite recursion is detected, and False otherwise.
122 -- If the type of the object being initialized uses the secondary stack
123 -- directly or indirectly, create a transient scope for the call to the
124 -- init proc. This is because we do not create transient scopes for the
125 -- initialization of individual components within the init proc itself.
126 -- Could be optimized away perhaps?
129 -- N is the node for a logical operator. If the operator is predefined, and
130 -- the root type of the operands is Standard.Boolean, then a check is made
131 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
132 -- the style check for Style_Check_Boolean_And_Or.
135 -- N is either an indexed component or a selected component. This function
136 -- returns true if the prefix refers to an object that has an address
137 -- clause (the case in which we may want to issue a warning).
140 -- Determine whether E is an access type declared by an access declaration,
141 -- and not an (anonymous) allocator type.
144 -- Utility to check whether the entity for an operator is a predefined
145 -- operator, in which case the expression is left as an operator in the
146 -- tree (else it is rewritten into a call). An instance of an intrinsic
147 -- conversion operation may be given an operator name, but is not treated
148 -- like an operator. Note that an operator that is an imported back-end
149 -- builtin has convention Intrinsic, but is expected to be rewritten into
150 -- a call, so such an operator is not treated as predefined by this
151 -- predicate.
154 -- If a default expression in entry call N depends on the discriminants
155 -- of the task, it must be replaced with a reference to the discriminant
156 -- of the task being called.
158 procedure Resolve_Op_Concat_Arg
163 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
164 -- concatenation operator. The operand is either of the array type or of
165 -- the component type. If the operand is an aggregate, and the component
166 -- type is composite, this is ambiguous if component type has aggregates.
169 -- Does the first part of the work of Resolve_Op_Concat
172 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
173 -- has been resolved. See Resolve_Op_Concat for details.
211 function Operator_Kind
214 -- Utility to map the name of an operator into the corresponding Node. Used
215 -- by other node rewriting procedures.
218 -- Resolve actuals of call, and add default expressions for missing ones.
219 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
220 -- called subprogram.
223 -- Called from Resolve_Call, when the prefix denotes an entry or element
224 -- of entry family. Actuals are resolved as for subprograms, and the node
225 -- is rebuilt as an entry call. Also called for protected operations. Typ
226 -- is the context type, which is used when the operation is a protected
227 -- function with no arguments, and the return value is indexed.
230 -- A call to a user-defined intrinsic operator is rewritten as a call to
231 -- the corresponding predefined operator, with suitable conversions. Note
232 -- that this applies only for intrinsic operators that denote predefined
233 -- operators, not ones that are intrinsic imports of back-end builtins.
236 -- Ditto, for arithmetic unary operators
239 -- If an operator node resolves to a call to a user-defined operator,
240 -- rewrite the node as a function call.
242 procedure Make_Call_Into_Operator
246 -- Inverse transformation: if an operator is given in functional notation,
247 -- then after resolving the node, transform into an operator node, so that
248 -- operands are resolved properly. Recall that predefined operators do not
249 -- have a full signature and special resolution rules apply.
251 procedure Rewrite_Renamed_Operator
255 -- An operator can rename another, e.g. in an instantiation. In that
256 -- case, the proper operator node must be constructed and resolved.
259 -- The String_Literal_Subtype is built for all strings that are not
260 -- operands of a static concatenation operation. If the argument is not
261 -- a N_String_Literal node, then the call has no effect.
264 -- Build subtype of array type, with the range specified by the slice
267 -- Called after N has been resolved and evaluated, but before range checks
268 -- have been applied. Currently simplifies a combination of floating-point
269 -- to integer conversion and Rounding or Truncation attribute.
272 -- A universal_fixed expression in an universal context is unambiguous if
273 -- there is only one applicable fixed point type. Determining whether there
274 -- is only one requires a search over all visible entities, and happens
275 -- only in very pathological cases (see 6115-006).
277 -------------------------
278 -- Ambiguous_Character --
279 -------------------------
284 begin
288 -- First the ones in Standard
293 -- Include Wide_Wide_Character in Ada 2005 mode
299 -- Now any other types that match
309 -------------------------
310 -- Analyze_And_Resolve --
311 -------------------------
314 begin
320 begin
325 -- Versions with check(s) suppressed
327 procedure Analyze_And_Resolve
331 is
334 begin
336 declare
338 begin
344 else
345 declare
347 begin
355 and then Scope_Is_Transient
356 then
357 -- This can only happen if a transient scope was created for an inner
358 -- expression, which will be removed upon completion of the analysis
359 -- of an enclosing construct. The transient scope must have the
360 -- suppress status of the enclosing environment, not of this Analyze
361 -- call.
364 Scope_Suppress;
368 procedure Analyze_And_Resolve
371 is
374 begin
376 declare
378 begin
384 else
385 declare
387 begin
396 Scope_Suppress;
400 ----------------------------
401 -- Check_Discriminant_Use --
402 ----------------------------
410 begin
411 -- Any use in a spec-expression is legal
418 -- Discriminant cannot be used to constrain a scalar type
425 then
430 -- The following check catches the unusual case where a
431 -- discriminant appears within an index constraint that is part
432 -- of a larger expression within a constraint on a component,
433 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
434 -- check case of record components, and note that a similar check
435 -- should also apply in the case of discriminant constraints
436 -- below. ???
438 -- Note that the check for N_Subtype_Declaration below is to
439 -- detect the valid use of discriminants in the constraints of a
440 -- subtype declaration when this subtype declaration appears
441 -- inside the scope of a record type (which is syntactically
442 -- illegal, but which may be created as part of derived type
443 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
444 -- for more info.
448 and then not
450 and then
452 N_Subtype_Declaration)
454 then
455 Error_Msg_N
460 -- Detect a common error:
462 -- type R (D : Positive := 100) is record
463 -- Name : String (1 .. D);
464 -- end record;
466 -- The default value causes an object of type R to be allocated
467 -- with room for Positive'Last characters. The RM does not mandate
468 -- the allocation of the maximum size, but that is what GNAT does
469 -- so we should warn the programmer that there is a problem.
478 -- Return True if type T has a large enough range that any
479 -- array whose index type covered the whole range of the type
480 -- would likely raise Storage_Error.
482 ------------------------
483 -- Large_Storage_Type --
484 ------------------------
487 begin
488 -- The type is considered large if its bounds are known at
489 -- compile time and if it requires at least as many bits as
490 -- a Positive to store the possible values.
494 and then
499 -- Start of processing for Check_Large
501 begin
502 -- Check that the Disc has a large range
508 -- If the enclosing type is limited, we allocate only the
509 -- default value, not the maximum, and there is no need for
510 -- a warning.
516 -- Check that it is the high bound
520 then
524 -- Check the array allows a large range at this bound. First
525 -- find the array
539 -- Next, find the dimension
547 loop
556 -- Now, check the dimension has a large range
562 -- Warn about the danger
564 Error_Msg_N
574 -- Legal case is in index or discriminant constraint
577 N_Discriminant_Association)
578 then
580 Error_Msg_N
585 then
586 Error_Msg_N
592 -- Otherwise, context is an expression. It should not be within (i.e. a
593 -- subexpression of) a constraint for a component.
595 else
599 N_Subtype_Indication,
600 N_Entry_Declaration)
601 loop
607 -- If the discriminant is used in an expression that is a bound of a
608 -- scalar type, an Itype is created and the bounds are attached to
609 -- its range, not to the original subtype indication. Such use is of
610 -- course a double fault.
614 N_Derived_Type_Definition)
617 -- The constraint itself may be given by a subtype indication,
618 -- rather than by a more common discrete range.
621 and then
625 then
626 Error_Msg_N
632 --------------------------------
633 -- Check_For_Visible_Operator --
634 --------------------------------
637 begin
639 Error_Msg_NE -- CODEFIX
641 Error_Msg_N -- CODEFIX
646 ----------------------------------
647 -- Check_Fully_Declared_Prefix --
648 ----------------------------------
650 procedure Check_Fully_Declared_Prefix
653 is
654 begin
655 -- Check that the designated type of the prefix of a dereference is
656 -- not an incomplete type. This cannot be done unconditionally, because
657 -- dereferences of private types are legal in default expressions. This
658 -- case is taken care of in Check_Fully_Declared, called below. There
659 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
661 -- This consideration also applies to similar checks for allocators,
662 -- qualified expressions, and type conversions.
664 -- An additional exception concerns other per-object expressions that
665 -- are not directly related to component declarations, in particular
666 -- representation pragmas for tasks. These will be per-object
667 -- expressions if they depend on discriminants or some global entity.
668 -- If the task has access discriminants, the designated type may be
669 -- incomplete at the point the expression is resolved. This resolution
670 -- takes place within the body of the initialization procedure, where
671 -- the discriminant is replaced by its discriminal.
675 then
678 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
679 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
680 -- Analyze_Object_Renaming, and Freeze_Entity.
686 E_Incomplete_Type
688 then
690 else
695 ------------------------------
696 -- Check_Infinite_Recursion --
697 ------------------------------
704 -- Check whether list of actuals is identical to list of formals of
705 -- called function (which is also the enclosing scope).
707 ------------------------
708 -- Same_Argument_List --
709 ------------------------
716 begin
719 else
737 -- Start of processing for Check_Infinite_Recursion
739 begin
740 -- Special case, if this is a procedure call and is a call to the
741 -- current procedure with the same argument list, then this is for
742 -- sure an infinite recursion and we insert a call to raise SE.
746 and then Same_Argument_List
747 then
748 declare
750 begin
754 then
766 -- If not that special case, search up tree, quitting if we reach a
767 -- construct (e.g. a conditional) that tells us that this is not a
768 -- case for an infinite recursion warning.
771 loop
774 -- If no parent, then we were not inside a subprogram, this can for
775 -- example happen when processing certain pragmas in a spec. Just
776 -- return False in this case.
782 -- Done if we get to subprogram body, this is definitely an infinite
783 -- recursion case if we did not find anything to stop us.
787 -- If appearing in conditional, result is false
790 N_And_Then,
791 N_Case_Expression,
792 N_Case_Statement,
793 N_If_Expression,
794 N_If_Statement)
795 then
800 then
801 -- If the call is the expression of a return statement and the
802 -- actuals are identical to the formals, it's worth a warning.
803 -- However, we skip this if there is an immediately preceding
804 -- raise statement, since the call is never executed.
806 -- Furthermore, this corresponds to a common idiom:
808 -- function F (L : Thing) return Boolean is
809 -- begin
810 -- raise Program_Error;
811 -- return F (L);
812 -- end F;
814 -- for generating a stub function
817 and then Same_Argument_List
818 then
821 -- OK, return statement is in a statement list, look for raise
823 declare
826 begin
827 -- Skip past N_Freeze_Entity nodes generated by expansion
832 loop
836 -- If no raise statement, give warning. We look at the
837 -- original node, because in the case of "raise ... with
838 -- ...", the node has been transformed into a call.
841 and then
849 else
861 -------------------------------
862 -- Check_Initialization_Call --
863 -------------------------------
869 -- Check whether the creation of an object of the type will involve
870 -- use of the secondary stack. If T is a record type, this is true
871 -- if the expression for some component uses the secondary stack, e.g.
872 -- through a call to a function that returns an unconstrained value.
873 -- False if T is controlled, because cleanups occur elsewhere.
875 -------------
876 -- Uses_SS --
877 -------------
884 begin
885 -- Normally we want to use the underlying type, but if it's not set
886 -- then continue with T.
903 then
904 -- The expression for a dynamic component may be rewritten
905 -- as a dereference, so retrieve original node.
909 -- Return True if the expression is a call to a function
910 -- (including an attribute function such as Image, or a
911 -- user-defined operator) with a result that requires a
912 -- transient scope.
919 then
932 else
937 -- Start of processing for Check_Initialization_Call
939 begin
940 -- Establish a transient scope if the type needs it
947 ---------------------------------------
948 -- Check_No_Direct_Boolean_Operators --
949 ---------------------------------------
952 begin
955 then
956 -- Restriction only applies to original source code
963 -- Do style check (but skip if in instance, error is on template)
972 ------------------------------
973 -- Check_Parameterless_Call --
974 ------------------------------
980 -- If the prefix is of an access_to_subprogram type, the node must be
981 -- rewritten as a call. Ditto if the prefix is overloaded and all its
982 -- interpretations are access to subprograms.
984 ---------------------------
985 -- Prefix_Is_Access_Subp --
986 ---------------------------
992 begin
993 -- If the context is an attribute reference that can apply to
994 -- functions, this is never a parameterless call (RM 4.1.4(6)).
998 Name_Code_Address,
999 Name_Access)
1000 then
1005 return
1008 else
1013 then
1024 -- Start of processing for Check_Parameterless_Call
1026 begin
1027 -- Defend against junk stuff if errors already detected
1034 then
1041 -- If the context expects a value, and the name is a procedure, this is
1042 -- most likely a missing 'Access. Don't try to resolve the parameterless
1043 -- call, error will be caught when the outer call is analyzed.
1048 and then
1050 N_Function_Call,
1051 N_Procedure_Call_Statement)
1052 then
1056 -- Rewrite as call if overloadable entity that is (or could be, in the
1057 -- overloaded case) a function call. If we know for sure that the entity
1058 -- is an enumeration literal, we do not rewrite it.
1060 -- If the entity is the name of an operator, it cannot be a call because
1061 -- operators cannot have default parameters. In this case, this must be
1062 -- a string whose contents coincide with an operator name. Set the kind
1063 -- of the node appropriately.
1071 -- Rewrite as call if it is an explicit dereference of an expression of
1072 -- a subprogram access type, and the subprogram type is not that of a
1073 -- procedure or entry.
1075 or else
1078 -- Rewrite as call if it is a selected component which is a function,
1079 -- this is the case of a call to a protected function (which may be
1080 -- overloaded with other protected operations).
1082 or else
1085 or else
1087 E_Procedure)
1090 -- If one of the above three conditions is met, rewrite as call. Apply
1091 -- the rewriting only once.
1093 then
1096 then
1098 -- This may be a prefixed call that was not fully analyzed, e.g.
1099 -- an actual in an instance.
1104 then
1112 -- The node is the name of the parameterless call. Preserve its
1113 -- descendants, which may be complex expressions.
1117 -- If overloaded, overload set belongs to new copy
1121 -- Change node to parameterless function call (note that the
1122 -- Parameter_Associations associations field is left set to Empty,
1123 -- its normal default value since there are no parameters)
1141 --------------------------------
1142 -- Is_Atomic_Ref_With_Address --
1143 --------------------------------
1148 begin
1152 else
1153 declare
1156 begin
1164 -----------------------------
1165 -- Is_Definite_Access_Type --
1166 -----------------------------
1170 begin
1176 ----------------------
1177 -- Is_Predefined_Op --
1178 ----------------------
1181 begin
1182 -- Predefined operators are intrinsic subprograms
1188 -- A call to a back-end builtin is never a predefined operator
1199 -----------------------------
1200 -- Make_Call_Into_Operator --
1201 -----------------------------
1203 procedure Make_Call_Into_Operator
1207 is
1222 -- If the operand is not universal, and the operator is given by an
1223 -- expanded name, verify that the operand has an interpretation with a
1224 -- type defined in the given scope of the operator.
1227 -- Find a type of the given class in package Pack that contains the
1228 -- operator.
1230 ---------------------------
1231 -- Operand_Type_In_Scope --
1232 ---------------------------
1239 begin
1243 else
1257 ---------------
1258 -- Type_In_P --
1259 ---------------
1265 -- Verify that node is not part of the type declaration for the
1266 -- candidate type, which would otherwise be invisible.
1268 -------------
1269 -- In_Decl --
1270 -------------
1276 begin
1285 else
1288 loop
1291 else
1300 -- Start of processing for Type_In_P
1302 begin
1303 -- If the context type is declared in the prefix package, this is the
1304 -- desired base type.
1309 else
1323 -- Start of processing for Make_Call_Into_Operator
1325 begin
1328 -- Binary operator
1338 -- Unary operator
1340 else
1346 -- If the operator is denoted by an expanded name, and the prefix is
1347 -- not Standard, but the operator is a predefined one whose scope is
1348 -- Standard, then this is an implicit_operator, inserted as an
1349 -- interpretation by the procedure of the same name. This procedure
1350 -- overestimates the presence of implicit operators, because it does
1351 -- not examine the type of the operands. Verify now that the operand
1352 -- type appears in the given scope. If right operand is universal,
1353 -- check the other operand. In the case of concatenation, either
1354 -- argument can be the component type, so check the type of the result.
1355 -- If both arguments are literals, look for a type of the right kind
1356 -- defined in the given scope. This elaborate nonsense is brought to
1357 -- you courtesy of b33302a. The type itself must be frozen, so we must
1358 -- find the type of the proper class in the given scope.
1360 -- A final wrinkle is the multiplication operator for fixed point types,
1361 -- which is defined in Standard only, and not in the scope of the
1362 -- fixed point type itself.
1367 -- If this is a package renaming, get renamed entity, which will be
1368 -- the scope of the operands if operaton is type-correct.
1374 -- If the entity being called is defined in the given package, it is
1375 -- a renaming of a predefined operator, and known to be legal.
1379 then
1382 -- Visibility does not need to be checked in an instance: if the
1383 -- operator was not visible in the generic it has been diagnosed
1384 -- already, else there is an implicit copy of it in the instance.
1392 then
1397 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1398 -- available.
1403 then
1406 else
1415 and then Is_Binary
1417 then
1423 -- Verify that the scope contains a type that corresponds to
1424 -- the given literal. Optimize the case where Pack is Standard.
1446 else
1455 else
1464 then
1467 -- If the type is defined elsewhere, and the operator is not
1468 -- defined in the given scope (by a renaming declaration, e.g.)
1469 -- then this is an error as well. If an extension of System is
1470 -- present, and the type may be defined there, Pack must be
1471 -- System itself.
1478 then
1481 else
1487 then
1494 Error_Msg_NE
1499 -- Detect a mismatch between the context type and the result type
1500 -- in the named package, which is otherwise not detected if the
1501 -- operands are universal. Check is only needed if source entity is
1502 -- an operator, not a function that renames an operator.
1509 and then not In_Instance
1510 then
1513 then
1514 -- Already checked above
1518 -- Operator may be defined in an extension of System
1522 then
1525 else
1526 -- Could we use Wrong_Type here??? (this would require setting
1527 -- Etype (N) to the actual type found where Typ was expected).
1538 else
1542 -- If this is a call to a function that renames a predefined equality,
1543 -- the renaming declaration provides a type that must be used to
1544 -- resolve the operands. This must be done now because resolution of
1545 -- the equality node will not resolve any remaining ambiguity, and it
1546 -- assumes that the first operand is not overloaded.
1551 then
1559 -- Do rewrite setting Comes_From_Source on the result if the original
1560 -- call came from source. Although it is not strictly the case that the
1561 -- operator as such comes from the source, logically it corresponds
1562 -- exactly to the function call in the source, so it should be marked
1563 -- this way (e.g. to make sure that validity checks work fine).
1565 declare
1567 begin
1572 -- If this is an arithmetic operator and the result type is private,
1573 -- the operands and the result must be wrapped in conversion to
1574 -- expose the underlying numeric type and expand the proper checks,
1575 -- e.g. on division.
1579 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1580 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1589 else
1593 -- If in ASIS_Mode, propagate operand types to original actuals of
1594 -- function call, which would otherwise not be fully resolved. If
1595 -- the call has already been constant-folded, nothing to do. We
1596 -- relocate the operand nodes rather than copy them, to preserve
1597 -- original_node pointers, given that the operands themselves may
1598 -- have been rewritten. If the call was itself a rewriting of an
1599 -- operator node, nothing to do.
1601 if ASIS_Mode
1604 then
1605 declare
1613 begin
1618 -- If the original call has named associations, replace the
1619 -- explicit actual parameter in the association with the proper
1620 -- resolved operand.
1625 then
1628 else
1633 else
1640 then
1643 else
1648 else
1652 else
1656 else
1666 -------------------
1667 -- Operator_Kind --
1668 -------------------
1670 function Operator_Kind
1673 is
1676 begin
1677 -- Use CASE statement or array???
1714 else
1718 -- Unary operators
1720 else
1729 else
1737 ----------------------------
1738 -- Preanalyze_And_Resolve --
1739 ----------------------------
1744 begin
1748 -- Normally, we suppress all checks for this preanalysis. There is no
1749 -- point in processing them now, since they will be applied properly
1750 -- and in the proper location when the default expressions reanalyzed
1751 -- and reexpanded later on. We will also have more information at that
1752 -- point for possible suppression of individual checks.
1754 -- However, in SPARK mode, most expansion is suppressed, and this
1755 -- later reanalysis and reexpansion may not occur. SPARK mode does
1756 -- require the setting of checking flags for proof purposes, so we
1757 -- do the SPARK preanalysis without suppressing checks.
1759 -- This special handling for SPARK mode is required for example in the
1760 -- case of Ada 2012 constructs such as quantified expressions, which are
1761 -- expanded in two separate steps.
1765 else
1769 Expander_Mode_Restore;
1773 -- Version without context type
1778 begin
1785 Expander_Mode_Restore;
1789 ----------------------------------
1790 -- Replace_Actual_Discriminants --
1791 ----------------------------------
1798 -- Comment needed???
1800 -------------------
1801 -- Process_Discr --
1802 -------------------
1807 begin
1813 then
1829 -- Start of processing for Replace_Actual_Discriminants
1831 begin
1845 else
1850 -------------
1851 -- Resolve --
1852 -------------
1868 -- Determine whether a node comes from a predefined library unit or
1869 -- Standard.
1872 -- Try and fix up a literal so that it matches its expected type. New
1873 -- literals are manufactured if necessary to avoid cascaded errors.
1876 -- Additional diagnostics when an ambiguous call has an ambiguous
1877 -- argument (typically a controlling actual).
1880 -- Called when attempt at resolving current expression fails
1882 ------------------------------------
1883 -- Comes_From_Predefined_Lib_Unit --
1884 -------------------------------------
1887 begin
1888 return
1890 or else Is_Predefined_File_Name
1894 --------------------
1895 -- Patch_Up_Value --
1896 --------------------
1899 begin
1916 then
1921 Char_Literal_Value =>
1937 -------------------------------
1938 -- Report_Ambiguous_Argument --
1939 -------------------------------
1946 begin
1950 then
1953 -- Could use comments on what is going on here???
1961 else
1970 -----------------------
1971 -- Resolution_Failed --
1972 -----------------------
1975 begin
1981 -- The caller will return without calling the expander, so we need
1982 -- to set the analyzed flag. Note that it is fine to set Analyzed
1983 -- to True even if we are in the middle of a shallow analysis,
1984 -- (see the spec of sem for more details) since this is an error
1985 -- situation anyway, and there is no point in repeating the
1986 -- analysis later (indeed it won't work to repeat it later, since
1987 -- we haven't got a clear resolution of which entity is being
1988 -- referenced.)
1994 -- Local variables
1998 -- Start of processing for Resolve
2000 begin
2005 -- A declaration may be subject to pragma Ghost. Set the mode now to
2006 -- ensure that any nodes generated during analysis and expansion are
2007 -- marked as Ghost.
2013 -- Access attribute on remote subprogram cannot be used for a non-remote
2014 -- access-to-subprogram type.
2018 Name_Unrestricted_Access,
2019 Name_Unchecked_Access)
2025 then
2026 Error_Msg_N
2032 -- If the context is a Remote_Access_To_Subprogram, access attributes
2033 -- must be resolved with the corresponding fat pointer. There is no need
2034 -- to check for the attribute name since the return type of an
2035 -- attribute is never a remote type.
2040 then
2041 declare
2049 begin
2050 -- Check that Typ is a remote access-to-subprogram type
2054 -- Prefix (N) must statically denote a remote subprogram
2055 -- declared in a package specification.
2059 Attr = Attribute_Unrestricted_Access
2060 then
2075 or else
2077 then
2079 Error_Msg_N
2081 N);
2084 -- If we are generating code in distributed mode, perform
2085 -- semantic checks against corresponding remote entities.
2087 if Expander_Active
2089 then
2090 Check_Subtype_Conformant
2092 Old_Id => Designated_Type
2118 then
2123 -- Return if already analyzed
2131 -- Any case of Any_Type as the Etype value means that we had a
2132 -- previous error.
2142 -- The resolution of an Expression_With_Actions is determined by
2143 -- its Expression.
2151 -- If not overloaded, then we know the type, and all that needs doing
2152 -- is to check that this type is compatible with the context.
2158 -- In the overloaded case, we must select the interpretation that
2159 -- is compatible with the context (i.e. the type passed to Resolve)
2161 else
2162 -- Loop through possible interpretations
2171 -- We are only interested in interpretations that are compatible
2172 -- with the expected type, any other interpretations are ignored.
2177 Write_Eol;
2180 else
2181 -- Skip the current interpretation if it is disabled by an
2182 -- abstract operator. This action is performed only when the
2183 -- type against which we are resolving is the same as the
2184 -- type of the interpretation.
2191 then
2199 -- First matching interpretation
2207 -- Matching interpretation that is not the first, maybe an
2208 -- error, but there are some cases where preference rules are
2209 -- used to choose between the two possibilities. These and
2210 -- some more obscure cases are handled in Disambiguate.
2212 else
2213 -- If the current statement is part of a predefined library
2214 -- unit, then all interpretations which come from user level
2215 -- packages should not be considered. Check previous and
2216 -- current one.
2224 -- Previous interpretation must be discarded
2234 -- Otherwise apply further disambiguation steps
2239 -- Disambiguation has succeeded. Skip the remaining
2240 -- interpretations.
2250 else
2251 -- Before we issue an ambiguity complaint, check for
2252 -- the case of a subprogram call where at least one
2253 -- of the arguments is Any_Type, and if so, suppress
2254 -- the message, since it is a cascaded error.
2257 declare
2261 begin
2273 Write_Eol;
2286 then
2291 then
2295 -- Not that special case, so issue message using the
2296 -- flag Ambiguous to control printing of the header
2297 -- message only at the start of an ambiguous set.
2302 then
2303 Error_Msg_N
2306 else
2307 Error_Msg_NE -- CODEFIX
2315 Error_Msg_N
2317 else
2318 Error_Msg_N -- CODEFIX
2324 then
2325 Report_Ambiguous_Argument;
2331 -- By default, the error message refers to the candidate
2332 -- interpretation. But if it is a predefined operator, it
2333 -- is implicitly declared at the declaration of the type
2334 -- of the operand. Recover the sloc of that declaration
2335 -- for the error message.
2341 Standard_Standard
2342 then
2347 then
2355 Standard_Standard
2356 then
2361 then
2365 -- If this is an indirect call, use the subprogram_type
2366 -- in the message, to have a meaningful location. Also
2367 -- indicate if this is an inherited operation, created
2368 -- by a type declaration.
2373 then
2375 Error_Msg_Sloc :=
2377 else
2384 then
2385 -- Special-case the message for universal_fixed
2386 -- operators, which are not declared with the type
2387 -- of the operand, but appear forever in Standard.
2391 then
2392 Error_Msg_N
2395 else
2396 Error_Msg_N
2400 elsif
2402 then
2403 Error_Msg_N
2405 else
2406 Error_Msg_N -- CODEFIX
2413 -- We have a matching interpretation, Expr_Type is the type
2414 -- from this interpretation, and Seen is the entity.
2416 -- For an operator, just set the entity name. The type will be
2417 -- set by the specific operator resolution routine.
2432 -- AI05-0139-2: Expression is overloaded because type has
2433 -- implicit dereference. If type matches context, no implicit
2434 -- dereference is involved.
2445 then
2446 -- If the node is a general indexing, the dereference is
2447 -- is inserted when resolving the rewritten form, else
2448 -- insert it now.
2452 then
2456 -- For an explicit dereference, attribute reference, range,
2457 -- short-circuit form (which is not an operator node), or call
2458 -- with a name that is an explicit dereference, there is
2459 -- nothing to be done at this point.
2462 N_Attribute_Reference,
2463 N_And_Then,
2464 N_Indexed_Component,
2465 N_Or_Else,
2466 N_Range,
2467 N_Selected_Component,
2468 N_Slice)
2470 then
2473 -- For procedure or function calls, set the type of the name,
2474 -- and also the entity pointer for the prefix.
2478 then
2485 then
2490 -- For all other cases, just set the type of the Name
2492 else
2500 -- Move to next interpretation
2508 -- At this stage Found indicates whether or not an acceptable
2509 -- interpretation exists. If not, then we have an error, except that if
2510 -- the context is Any_Type as a result of some other error, then we
2511 -- suppress the error report.
2516 -- If type we are looking for is Void, then this is the procedure
2517 -- call case, and the error is simply that what we gave is not a
2518 -- procedure name (we think of procedure calls as expressions with
2519 -- types internally, but the user doesn't think of them this way).
2523 -- Special case message if function used as a procedure
2528 then
2529 Error_Msg_NE
2533 -- Otherwise give general message (not clear what cases this
2534 -- covers, but no harm in providing for them).
2536 else
2542 -- Otherwise we do have a subexpression with the wrong type
2544 -- Check for the case of an allocator which uses an access type
2545 -- instead of the designated type. This is a common error and we
2546 -- specialize the message, posting an error on the operand of the
2547 -- allocator, complaining that we expected the designated type of
2548 -- the allocator.
2554 then
2558 -- Check for view mismatch on Null in instances, for which the
2559 -- view-swapping mechanism has no identifier.
2565 then
2571 -- Check for an aggregate. Sometimes we can get bogus aggregates
2572 -- from misuse of parentheses, and we are about to complain about
2573 -- the aggregate without even looking inside it.
2575 -- Instead, if we have an aggregate of type Any_Composite, then
2576 -- analyze and resolve the component fields, and then only issue
2577 -- another message if we get no errors doing this (otherwise
2578 -- assume that the errors in the aggregate caused the problem).
2582 then
2583 -- Disable expansion in any case. If there is a type mismatch
2584 -- it may be fatal to try to expand the aggregate. The flag
2585 -- would otherwise be set to false when the error is posted.
2589 declare
2591 -- Check one aggregate, and set Found to True if we have a
2592 -- definite error in any of its elements
2595 -- Check one element of aggregate and set Found to True if
2596 -- we definitely have an error in the element.
2598 ----------------
2599 -- Check_Aggr --
2600 ----------------
2605 begin
2618 -- If this is a default-initialized component, then
2619 -- there is nothing to check. The box will be
2620 -- replaced by the appropriate call during late
2621 -- expansion.
2632 ----------------
2633 -- Check_Elmt --
2634 ----------------
2637 begin
2638 -- If we have a nested aggregate, go inside it (to
2639 -- attempt a naked analyze-resolve of the aggregate can
2640 -- cause undesirable cascaded errors). Do not resolve
2641 -- expression if it needs a type from context, as for
2642 -- integer * fixed expression.
2647 else
2652 then
2662 begin
2667 -- Looks like we have a type error, but check for special case
2668 -- of Address wanted, integer found, with the configuration pragma
2669 -- Allow_Integer_Address active. If we have this case, introduce
2670 -- an unchecked conversion to allow the integer expression to be
2671 -- treated as an Address. The reverse case of integer wanted,
2672 -- Address found, is treated in an analogous manner.
2681 -- That special Allow_Integer_Address check did not appply, so we
2682 -- have a real type error. If an error message was issued already,
2683 -- Found got reset to True, so if it's still False, issue standard
2684 -- Wrong_Type message.
2688 declare
2691 begin
2697 -- Protected operation: retrieve operation name
2701 else
2706 Error_Msg_NE
2712 declare
2716 begin
2723 Error_Msg_NE
2729 else
2733 else
2739 Resolution_Failed;
2743 -- Test if we have more than one interpretation for the context
2746 Resolution_Failed;
2750 -- Only one intepretation
2752 else
2753 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2754 -- the "+" on T is abstract, and the operands are of universal type,
2755 -- the above code will have (incorrectly) resolved the "+" to the
2756 -- universal one in Standard. Therefore check for this case and give
2757 -- an error. We can't do this earlier, because it would cause legal
2758 -- cases to get errors (when some other type has an abstract "+").
2764 then
2769 then
2770 Error_Msg_NE
2779 -- Here we have an acceptable interpretation for the context
2781 -- Propagate type information and normalize tree for various
2782 -- predefined operations. If the context only imposes a class of
2783 -- types, rather than a specific type, propagate the actual type
2784 -- downward.
2790 Typ = Any_Discrete
2791 then
2794 -- Any_Fixed is legal in a real context only if a specific fixed-
2795 -- point type is imposed. If Norman Cohen can be confused by this,
2796 -- it deserves a separate message.
2800 then
2807 -- A user-defined operator is transformed into a function call at
2808 -- this point, so that further processing knows that operators are
2809 -- really operators (i.e. are predefined operators). User-defined
2810 -- operators that are intrinsic are just renamings of the predefined
2811 -- ones, and need not be turned into calls either, but if they rename
2812 -- a different operator, we must transform the node accordingly.
2813 -- Instantiations of Unchecked_Conversion are intrinsic but are
2814 -- treated as functions, even if given an operator designator.
2819 then
2825 and then
2827 N_Subprogram_Renaming_Declaration
2828 then
2831 -- If the node is rewritten, it will be fully resolved in
2832 -- Rewrite_Renamed_Operator.
2843 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2845 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2847 when N_Short_Circuit
2848 => Resolve_Short_Circuit (N, Ctx_Type);
2850 when N_Attribute_Reference
2851 => Resolve_Attribute (N, Ctx_Type);
2853 when N_Case_Expression
2854 => Resolve_Case_Expression (N, Ctx_Type);
2856 when N_Character_Literal
2857 => Resolve_Character_Literal (N, Ctx_Type);
2859 when N_Expanded_Name
2860 => Resolve_Entity_Name (N, Ctx_Type);
2862 when N_Explicit_Dereference
2863 => Resolve_Explicit_Dereference (N, Ctx_Type);
2865 when N_Expression_With_Actions
2866 => Resolve_Expression_With_Actions (N, Ctx_Type);
2868 when N_Extension_Aggregate
2869 => Resolve_Extension_Aggregate (N, Ctx_Type);
2871 when N_Function_Call
2872 => Resolve_Call (N, Ctx_Type);
2874 when N_Identifier
2875 => Resolve_Entity_Name (N, Ctx_Type);
2877 when N_If_Expression
2878 => Resolve_If_Expression (N, Ctx_Type);
2880 when N_Indexed_Component
2881 => Resolve_Indexed_Component (N, Ctx_Type);
2883 when N_Integer_Literal
2884 => Resolve_Integer_Literal (N, Ctx_Type);
2886 when N_Membership_Test
2887 => Resolve_Membership_Op (N, Ctx_Type);
2889 when N_Null => Resolve_Null (N, Ctx_Type);
2891 when N_Op_And | N_Op_Or | N_Op_Xor
2892 => Resolve_Logical_Op (N, Ctx_Type);
2894 when N_Op_Eq | N_Op_Ne
2895 => Resolve_Equality_Op (N, Ctx_Type);
2897 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2898 => Resolve_Comparison_Op (N, Ctx_Type);
2900 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2902 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2903 N_Op_Divide | N_Op_Mod | N_Op_Rem
2905 => Resolve_Arithmetic_Op (N, Ctx_Type);
2907 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2909 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2911 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2912 => Resolve_Unary_Op (N, Ctx_Type);
2914 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2916 when N_Procedure_Call_Statement
2917 => Resolve_Call (N, Ctx_Type);
2919 when N_Operator_Symbol
2920 => Resolve_Operator_Symbol (N, Ctx_Type);
2922 when N_Qualified_Expression
2923 => Resolve_Qualified_Expression (N, Ctx_Type);
2925 -- Why is the following null, needs a comment ???
2927 when N_Quantified_Expression
2928 => null;
2930 when N_Raise_Expression
2931 => Resolve_Raise_Expression (N, Ctx_Type);
2933 when N_Raise_xxx_Error
2934 => Set_Etype (N, Ctx_Type);
2936 when N_Range => Resolve_Range (N, Ctx_Type);
2938 when N_Real_Literal
2939 => Resolve_Real_Literal (N, Ctx_Type);
2941 when N_Reference => Resolve_Reference (N, Ctx_Type);
2943 when N_Selected_Component
2944 => Resolve_Selected_Component (N, Ctx_Type);
2946 when N_Slice => Resolve_Slice (N, Ctx_Type);
2948 when N_String_Literal
2949 => Resolve_String_Literal (N, Ctx_Type);
2951 when N_Type_Conversion
2952 => Resolve_Type_Conversion (N, Ctx_Type);
2954 when N_Unchecked_Expression =>
2955 Resolve_Unchecked_Expression (N, Ctx_Type);
2957 when N_Unchecked_Type_Conversion =>
2958 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2959 end case;
2961 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2962 -- expression of an anonymous access type that occurs in the context
2963 -- of a named general access type, except when the expression is that
2964 -- of a membership test. This ensures proper legality checking in
2965 -- terms of allowed conversions (expressions that would be illegal to
2966 -- convert implicitly are allowed in membership tests).
2968 if Ada_Version >= Ada_2012
2969 and then Ekind (Ctx_Type) = E_General_Access_Type
2970 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2971 and then Nkind (Parent (N)) not in N_Membership_Test
2972 then
2973 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2974 Analyze_And_Resolve (N, Ctx_Type);
2975 end if;
2977 -- If the subexpression was replaced by a non-subexpression, then
2978 -- all we do is to expand it. The only legitimate case we know of
2979 -- is converting procedure call statement to entry call statements,
2980 -- but there may be others, so we are making this test general.
2982 if Nkind (N) not in N_Subexpr then
2983 Debug_A_Exit ("resolving ", N, " (done)");
2984 Expand (N);
2985 Ghost_Mode := Save_Ghost_Mode;
2986 return;
2987 end if;
2989 -- The expression is definitely NOT overloaded at this point, so
2990 -- we reset the Is_Overloaded flag to avoid any confusion when
2991 -- reanalyzing the node.
2993 Set_Is_Overloaded (N, False);
2995 -- Freeze expression type, entity if it is a name, and designated
2996 -- type if it is an allocator (RM 13.14(10,11,13)).
2998 -- Now that the resolution of the type of the node is complete, and
2999 -- we did not detect an error, we can expand this node. We skip the
3000 -- expand call if we are in a default expression, see section
3001 -- "Handling of Default Expressions" in Sem spec.
3003 Debug_A_Exit ("resolving ", N, " (done)");
3005 -- We unconditionally freeze the expression, even if we are in
3006 -- default expression mode (the Freeze_Expression routine tests this
3007 -- flag and only freezes static types if it is set).
3009 -- Ada 2012 (AI05-177): The declaration of an expression function
3010 -- does not cause freezing, but we never reach here in that case.
3011 -- Here we are resolving the corresponding expanded body, so we do
3012 -- need to perform normal freezing.
3014 Freeze_Expression (N);
3016 -- Now we can do the expansion
3018 Expand (N);
3019 end if;
3021 Ghost_Mode := Save_Ghost_Mode;
3022 end Resolve;
3024 -------------
3025 -- Resolve --
3026 -------------
3028 -- Version with check(s) suppressed
3030 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3031 begin
3032 if Suppress = All_Checks then
3033 declare
3034 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3035 begin
3036 Scope_Suppress.Suppress := (others => True);
3037 Resolve (N, Typ);
3038 Scope_Suppress.Suppress := Sva;
3039 end;
3041 else
3042 declare
3043 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3044 begin
3045 Scope_Suppress.Suppress (Suppress) := True;
3046 Resolve (N, Typ);
3047 Scope_Suppress.Suppress (Suppress) := Svg;
3048 end;
3049 end if;
3050 end Resolve;
3052 -------------
3053 -- Resolve --
3054 -------------
3056 -- Version with implicit type
3058 procedure Resolve (N : Node_Id) is
3059 begin
3060 Resolve (N, Etype (N));
3061 end Resolve;
3063 ---------------------
3064 -- Resolve_Actuals --
3065 ---------------------
3067 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3068 Loc : constant Source_Ptr := Sloc (N);
3069 A : Node_Id;
3070 A_Id : Entity_Id;
3071 A_Typ : Entity_Id;
3072 F : Entity_Id;
3073 F_Typ : Entity_Id;
3074 Prev : Node_Id := Empty;
3075 Orig_A : Node_Id;
3076 Real_F : Entity_Id;
3078 Real_Subp : Entity_Id;
3079 -- If the subprogram being called is an inherited operation for
3080 -- a formal derived type in an instance, Real_Subp is the subprogram
3081 -- that will be called. It may have different formal names than the
3082 -- operation of the formal in the generic, so after actual is resolved
3083 -- the name of the actual in a named association must carry the name
3084 -- of the actual of the subprogram being called.
3086 procedure Check_Aliased_Parameter;
3087 -- Check rules on aliased parameters and related accessibility rules
3088 -- in (RM 3.10.2 (10.2-10.4)).
3090 procedure Check_Argument_Order;
3091 -- Performs a check for the case where the actuals are all simple
3092 -- identifiers that correspond to the formal names, but in the wrong
3093 -- order, which is considered suspicious and cause for a warning.
3095 procedure Check_Prefixed_Call;
3096 -- If the original node is an overloaded call in prefix notation,
3098 -- Try_Object_Operation has already verified that there is a valid
3099 -- interpretation, but the form of the actual can only be determined
3100 -- once the primitive operation is identified.
3103 -- If the actual is missing in a call, insert in the actuals list
3104 -- an instance of the default expression. The insertion is always
3105 -- a named association.
3107 procedure Property_Error
3111 -- Emit an error concerning variable Var with entity Var_Id that has
3112 -- enabled property Prop_Nam when it acts as an actual parameter in a
3113 -- call and the corresponding formal parameter is of mode IN.
3116 -- Check whether T1 and T2, or their full views, are derived from a
3117 -- common type. Used to enforce the restrictions on array conversions
3118 -- of AI95-00246.
3121 -- Predicate to determine whether an actual that is a concatenation
3122 -- will be evaluated statically and does not need a transient scope.
3123 -- This must be determined before the actual is resolved and expanded
3124 -- because if needed the transient scope must be introduced earlier.
3126 -----------------------------
3127 -- Check_Aliased_Parameter --
3128 -----------------------------
3133 begin
3141 else
3148 -- In a generic body assume the worst for generic formals:
3149 -- they can have a constrained partial view (AI05-041).
3155 then
3158 else
3163 else
3175 then
3183 then
3184 Error_Msg_N
3190 --------------------------
3191 -- Check_Argument_Order --
3192 --------------------------
3195 begin
3196 -- Nothing to do if no parameters, or original node is neither a
3197 -- function call nor a procedure call statement (happens in the
3198 -- operator-transformed-to-function call case), or the call does
3199 -- not come from source, or this warning is off.
3201 if not Warn_On_Parameter_Order
3205 then
3209 declare
3212 begin
3213 -- Nothing to do if only one parameter
3219 -- Here if at least two arguments
3221 declare
3227 -- Set True if an out of order case is found
3229 begin
3230 -- Collect identifier names of actuals, fail if any actual is
3231 -- not a simple identifier, and record max length of name.
3237 else
3243 -- If we got this far, all actuals are identifiers and the list
3244 -- of their names is stored in the Actuals array.
3249 -- If we ran out of formals, that's odd, probably an error
3250 -- which will be detected elsewhere, but abandon the search.
3256 -- If name matches and is in order OK
3261 else
3262 -- If no match, see if it is elsewhere in list and if so
3263 -- flag potential wrong order if type is compatible.
3267 and then
3269 then
3275 -- No match
3283 -- If Formals left over, also probably an error, skip warning
3289 -- Here we give the warning if something was out of order
3292 Error_Msg_N
3299 -------------------------
3300 -- Check_Prefixed_Call --
3301 -------------------------
3310 begin
3311 -- Check whether the call is a prefixed call, with or without
3312 -- additional actuals.
3315 or else
3321 then
3324 then
3325 -- Introduce dereference on object in prefix
3327 New_A :=
3335 then
3336 -- Introduce an implicit 'Access in prefix
3339 Error_Msg_NE
3355 --------------------
3356 -- Insert_Default --
3357 --------------------
3363 begin
3364 -- Missing argument in call, nothing to insert
3369 else
3370 -- Note that we do a full New_Copy_Tree, so that any associated
3371 -- Itypes are properly copied. This may not be needed any more,
3372 -- but it does no harm as a safety measure. Defaults of a generic
3373 -- formal may be out of bounds of the corresponding actual (see
3374 -- cc1311b) and an additional check may be required.
3376 Actval :=
3377 New_Copy_Tree
3384 then
3390 then
3393 then
3394 -- If default is a real literal, do not introduce a
3395 -- conversion whose effect may depend on the run-time
3396 -- size of universal real.
3400 else
3411 -- Resolve aggregates with their base type, to avoid scope
3412 -- anomalies: the subtype was first built in the subprogram
3413 -- declaration, and the current call may be nested.
3417 else
3421 else
3424 -- See note above concerning aggregates
3428 then
3431 -- Resolve entities with their own type, which may differ from
3432 -- the type of a reference in a generic context (the view
3433 -- swapping mechanism did not anticipate the re-analysis of
3434 -- default values in calls).
3439 else
3444 -- If default is a tag indeterminate function call, propagate tag
3445 -- to obtain proper dispatching.
3449 then
3455 -- If the default expression raises constraint error, then just
3456 -- silently replace it with an N_Raise_Constraint_Error node, since
3457 -- we already gave the warning on the subprogram spec. If node is
3458 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3459 -- the warnings removal machinery.
3463 then
3471 Assoc :=
3476 -- Case of insertion is first named actual
3480 then
3487 else
3491 else
3495 -- Case of insertion is not first named actual
3497 else
3498 Set_Next_Named_Actual
3510 --------------------
3511 -- Property_Error --
3512 --------------------
3514 procedure Property_Error
3518 is
3519 begin
3521 Error_Msg_NE
3527 -------------------
3528 -- Same_Ancestor --
3529 -------------------
3535 begin
3538 then
3544 then
3551 --------------------------
3552 -- Static_Concatenation --
3553 --------------------------
3556 begin
3563 -- Concatenation is static when both operands are static and
3564 -- the concatenation operator is a predefined one.
3567 and then
3569 and then
3574 declare
3576 begin
3579 and then
3583 else
3589 -- Start of processing for Resolve_Actuals
3591 begin
3592 Check_Argument_Order;
3596 and then In_Instance
3599 then
3601 else
3606 Check_Prefixed_Call;
3620 -- If we have an error in any actual or formal, indicated by a type
3621 -- of Any_Type, then abandon resolution attempt, and set result type
3622 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3623 -- type is imposed from context.
3627 then
3634 -- Case where actual is present
3636 -- If the actual is an entity, generate a reference to it now. We
3637 -- do this before the actual is resolved, because a formal of some
3638 -- protected subprogram, or a task discriminant, will be rewritten
3639 -- during expansion, and the source entity reference may be lost.
3644 then
3650 then
3657 -- RM 6.4.1(12): For an out parameter that is passed by
3658 -- copy, the formal parameter object is created, and:
3660 -- * For an access type, the formal parameter is initialized
3661 -- from the value of the actual, without checking that the
3662 -- value satisfies any constraint, any predicate, or any
3663 -- exclusion of the null value.
3665 -- * For a scalar type that has the Default_Value aspect
3666 -- specified, the formal parameter is initialized from the
3667 -- value of the actual, without checking that the value
3668 -- satisfies any constraint or any predicate.
3669 -- I do not understand why this case is included??? this is
3670 -- not a case where an OUT parameter is treated as IN OUT.
3672 -- * For a composite type with discriminants or that has
3673 -- implicit initial values for any subcomponents, the
3674 -- behavior is as for an in out parameter passed by copy.
3676 -- Hence for these cases we generate the read reference now
3677 -- (the write reference will be generated later by
3678 -- Note_Possible_Modification).
3681 and then
3683 or else
3685 and then
3687 or else
3690 or else Is_Partially_Initialized_Type
3692 then
3702 then
3703 -- If style checking mode on, check match of formal name
3711 -- If the formal is Out or In_Out, do not resolve and expand the
3712 -- conversion, because it is subsequently expanded into explicit
3713 -- temporaries and assignments. However, the object of the
3714 -- conversion can be resolved. An exception is the case of tagged
3715 -- type conversion with a class-wide actual. In that case we want
3716 -- the tag check to occur and no temporary will be needed (no
3717 -- representation change can occur) and the parameter is passed by
3718 -- reference, so we go ahead and resolve the type conversion.
3719 -- Another exception is the case of reference to component or
3720 -- subcomponent of a bit-packed array, in which case we want to
3721 -- defer expansion to the point the in and out assignments are
3722 -- performed.
3727 then
3730 then
3731 -- In a view conversion, the conversion must be legal in
3732 -- both directions, and thus both component types must be
3733 -- aliased, or neither (4.6 (8)).
3735 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3736 -- the privacy requirement should not apply to generic
3737 -- types, and should be checked in an instance. ARG query
3738 -- is in order ???
3742 then
3743 Error_Msg_N
3747 -- Comment here??? what set of cases???
3749 elsif
3751 then
3752 -- Check view conv between unrelated by ref array types
3756 then
3757 Error_Msg_N
3761 -- In Ada 2005 mode, check view conversion component
3762 -- type cannot be private, tagged, or volatile. Note
3763 -- that we only apply this to source conversions. The
3764 -- generated code can contain conversions which are
3765 -- not subject to this test, and we cannot extract the
3766 -- component type in such cases since it is not present.
3770 then
3771 declare
3773 Component_Type
3775 begin
3780 then
3781 Error_Msg_N
3792 -- Resolve expression if conversion is all OK
3797 then
3801 -- If the actual is a function call that returns a limited
3802 -- unconstrained object that needs finalization, create a
3803 -- transient scope for it, so that it can receive the proper
3804 -- finalization list.
3809 and then Expander_Active
3811 then
3815 -- A small optimization: if one of the actuals is a concatenation
3816 -- create a block around a procedure call to recover stack space.
3817 -- This alleviates stack usage when several procedure calls in
3818 -- the same statement list use concatenation. We do not perform
3819 -- this wrapping for code statements, where the argument is a
3820 -- static string, and we want to preserve warnings involving
3821 -- sequences of such statements.
3825 and then Expander_Active
3826 and then
3830 then
3834 else
3838 and then
3841 then
3842 Error_Msg_N
3855 -- (Ada 2005: AI-251): If the actual is an allocator whose
3856 -- directly designated type is a class-wide interface, we build
3857 -- an anonymous access type to use it as the type of the
3858 -- allocator. Later, when the subprogram call is expanded, if
3859 -- the interface has a secondary dispatch table the expander
3860 -- will add a type conversion to force the correct displacement
3861 -- of the pointer.
3864 declare
3870 begin
3873 then
3876 Set_Directly_Designated_Type
3881 -- Ada 2005, AI-162:If the actual is an allocator, the
3882 -- innermost enclosing statement is the master of the
3883 -- created object. This needs to be done with expansion
3884 -- enabled only, otherwise the transient scope will not
3885 -- be removed in the expansion of the wrapped construct.
3888 and then Expander_Active
3889 then
3899 -- (Ada 2005): The call may be to a primitive operation of a
3900 -- tagged synchronized type, declared outside of the type. In
3901 -- this case the controlling actual must be converted to its
3902 -- corresponding record type, which is the formal type. The
3903 -- actual may be a subtype, either because of a constraint or
3904 -- because it is a generic actual, so use base type to locate
3905 -- concurrent type.
3912 then
3913 -- If the actual is overloaded, look for an interpretation
3914 -- that has a synchronized type.
3919 else
3920 declare
3924 begin
3929 then
3939 declare
3942 begin
3945 else
3949 -- Tagged synchronized type (case 1): the actual is a
3950 -- concurrent type.
3954 then
3956 Unchecked_Convert_To
3960 -- Tagged synchronized type (case 2): the formal is a
3961 -- concurrent type.
3964 and then Present
3969 then
3972 -- Common case
3974 else
3979 -- Not a synchronized operation
3981 else
3989 -- An actual cannot be an untagged formal incomplete type
3994 then
3995 Error_Msg_N
4001 N_Procedure_Call_Statement)
4002 then
4003 -- In formal mode, check that actual parameters matching
4004 -- formals of tagged types are objects (or ancestor type
4005 -- conversions of objects), not general expressions.
4012 declare
4017 begin
4019 Check_SPARK_05_Restriction
4022 -- In formal mode, the only view conversions are those
4023 -- involving ancestor conversion of an extended type.
4025 elsif not
4031 then
4032 if Ekind_In
4034 then
4035 Check_SPARK_05_Restriction
4038 else
4039 Check_SPARK_05_Restriction
4043 else
4048 else
4052 -- In formal mode, the only view conversions are those
4053 -- involving ancestor conversion of an extended type.
4057 then
4058 Check_SPARK_05_Restriction
4064 -- has warnings suppressed, then we reset Never_Set_In_Source for
4065 -- the calling entity. The reason for this is to catch cases like
4066 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4067 -- uses trickery to modify an IN parameter.
4074 then
4078 -- Perform error checks for IN and IN OUT parameters
4082 -- Check unset reference. For scalar parameters, it is clearly
4083 -- wrong to pass an uninitialized value as either an IN or
4084 -- IN-OUT parameter. For composites, it is also clearly an
4085 -- error to pass a completely uninitialized value as an IN
4086 -- parameter, but the case of IN OUT is trickier. We prefer
4087 -- not to give a warning here. For example, suppose there is
4088 -- a routine that sets some component of a record to False.
4089 -- It is perfectly reasonable to make this IN-OUT and allow
4090 -- either initialized or uninitialized records to be passed
4091 -- in this case.
4093 -- For partially initialized composite values, we also avoid
4094 -- warnings, since it is quite likely that we are passing a
4095 -- partially initialized value and only the initialized fields
4096 -- will in fact be read in the subprogram.
4101 then
4105 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4106 -- actual to a nested call, since this constitutes a reading of
4107 -- the parameter, which is not allowed.
4112 then
4117 -- Case of OUT or IN OUT parameter
4121 -- For an Out parameter, check for useless assignment. Note
4122 -- that we can't set Last_Assignment this early, because we may
4123 -- kill current values in Resolve_Call, and that call would
4124 -- clobber the Last_Assignment field.
4126 -- Note: call Warn_On_Useless_Assignment before doing the check
4127 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4128 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4129 -- reflects the last assignment, not this one.
4136 then
4141 -- Validate the form of the actual. Note that the call to
4142 -- Is_OK_Variable_For_Out_Formal generates the required
4143 -- reference in this case.
4145 -- A call to an initialization procedure for an aggregate
4146 -- component may initialize a nested component of a constant
4147 -- designated object. In this context the object is variable.
4151 then
4155 and then
4158 then
4159 Error_Msg_N
4165 -- What's the following about???
4169 else
4170 Kill_All_Checks;
4179 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4183 -- Apply predicate tests except in certain special cases. Note
4184 -- that it might be more consistent to apply these only when
4185 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4186 -- for the outbound predicate tests ???
4192 -- Apply required constraint checks
4194 -- Gigi looks at the check flag and uses the appropriate types.
4195 -- For now since one flag is used there is an optimization
4196 -- which might not be done in the IN OUT case since Gigi does
4197 -- not do any analysis. More thought required about this ???
4199 -- In fact is this comment obsolete??? doesn't the expander now
4200 -- generate all these tests anyway???
4213 then
4216 -- For view conversions of a discriminated object, apply
4217 -- check to object itself, the conversion alreay has the
4218 -- proper type.
4222 then
4229 then
4235 then
4238 else
4242 -- Ada 2005 (AI-231): Note that the controlling parameter case
4243 -- already existed in Ada 95, which is partially checked
4244 -- elsewhere (see Checks), and we don't want the warning
4245 -- message to differ.
4250 then
4252 Apply_Compile_Time_Constraint_Error
4258 Apply_Compile_Time_Constraint_Error
4267 -- Checks for OUT parameters and IN OUT parameters
4271 -- If there is a type conversion, to make sure the return value
4272 -- meets the constraints of the variable before the conversion.
4276 Apply_Scalar_Range_Check
4278 else
4279 Apply_Range_Check
4283 -- If no conversion apply scalar range checks and length checks
4284 -- base on the subtype of the actual (NOT that of the formal).
4286 else
4291 then
4293 else
4298 -- Note: we do not apply the predicate checks for the case of
4299 -- OUT and IN OUT parameters. They are instead applied in the
4300 -- Expand_Actuals routine in Exp_Ch6.
4303 -- An actual associated with an access parameter is implicitly
4304 -- converted to the anonymous access type of the formal and must
4305 -- satisfy the legality checks for access conversions.
4309 Error_Msg_N
4313 -- If the actual is an access selected component of a variable,
4314 -- the call may modify its designated object. It is reasonable
4315 -- to treat this as a potential modification of the enclosing
4316 -- record, to prevent spurious warnings that it should be
4317 -- declared as a constant, because intuitively programmers
4318 -- regard the designated subcomponent as part of the record.
4323 then
4328 -- Check bad case of atomic/volatile argument (RM C.6(12))
4332 then
4335 then
4336 Error_Msg_NE
4342 then
4343 Error_Msg_NE
4349 -- Check that subprograms don't have improper controlling
4350 -- arguments (RM 3.9.2 (9)).
4352 -- A primitive operation may have an access parameter of an
4353 -- incomplete tagged type, but a dispatching call is illegal
4354 -- if the type is still incomplete.
4360 declare
4362 begin
4366 then
4367 Error_Msg_NE
4378 -- Apply legality rule 3.9.2 (9/1)
4383 and then not In_Instance
4384 then
4389 Error_Msg_NE
4393 -- Apply the checks described in 3.10.2(27): if the context is a
4394 -- specific access-to-object, the actual cannot be class-wide.
4395 -- Use base type to exclude access_to_subprogram cases.
4402 and then
4407 -- Disable these checks for call to imported C++ subprograms
4409 and then not
4413 then
4414 Error_Msg_N
4419 Error_Msg_NE
4424 Check_Aliased_Parameter;
4428 -- If it is a named association, treat the selector_name as a
4429 -- proper identifier, and mark the corresponding entity.
4433 -- Ignore reference in SPARK mode, as it refers to an entity not
4434 -- in scope at the point of reference, so the reference should
4435 -- be ignored for computing effects of subprograms.
4437 and then not GNATprove_Mode
4438 then
4439 -- If subprogram is overridden, use name of formal that
4440 -- is being called.
4446 else
4460 -- The following checks are only relevant when SPARK_Mode is on as
4461 -- they are not standard Ada legality rule. Internally generated
4462 -- temporaries are ignored.
4467 then
4468 -- An effectively volatile object may act as an actual when the
4469 -- corresponding formal is of a non-scalar effectively volatile
4470 -- type (SPARK RM 7.1.3(12)).
4474 then
4477 -- An effectively volatile object may act as an actual in a
4478 -- call to an instance of Unchecked_Conversion.
4479 -- (SPARK RM 7.1.3(12)).
4484 else
4485 Error_Msg_N
4490 -- Detect an external variable with an enabled property that
4491 -- does not match the mode of the corresponding formal in a
4492 -- procedure call. Functions are not considered because they
4493 -- cannot have effectively volatile formal parameters in the
4494 -- first place.
4501 then
4514 -- A formal parameter of a specific tagged type whose related
4515 -- subprogram is subject to pragma Extensions_Visible with value
4516 -- "False" cannot act as an actual in a subprogram with value
4517 -- "True" (SPARK RM 6.1.7(3)).
4521 Extensions_Visible_True
4522 then
4523 Error_Msg_N
4526 Error_Msg_NE
4530 -- The actual parameter of a Ghost subprogram whose formal is of
4531 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(13)).
4539 then
4540 Error_Msg_NE
4546 else
4553 -- Case where actual is not present
4555 else
4556 Insert_Default;
4567 -----------------------
4568 -- Resolve_Allocator --
4569 -----------------------
4581 procedure Check_Allocator_Discrim_Accessibility
4584 -- Check that accessibility level associated with an access discriminant
4585 -- initialized in an allocator by the expression Disc_Exp is not deeper
4586 -- than the level of the allocator type Alloc_Typ. An error message is
4587 -- issued if this condition is violated. Specialized checks are done for
4588 -- the cases of a constraint expression which is an access attribute or
4589 -- an access discriminant.
4592 -- If the allocator is an actual in a call, it is allowed to be class-
4593 -- wide when the context is not because it is a controlling actual.
4595 -------------------------------------------
4596 -- Check_Allocator_Discrim_Accessibility --
4597 -------------------------------------------
4599 procedure Check_Allocator_Discrim_Accessibility
4602 is
4603 begin
4606 then
4607 Error_Msg_N
4610 -- When the expression is an Access attribute the level of the prefix
4611 -- object must not be deeper than that of the allocator's type.
4615 Attribute_Access
4618 then
4619 Error_Msg_N
4621 Disc_Exp);
4623 -- When the expression is an access discriminant the check is against
4624 -- the level of the prefix object.
4630 then
4631 Error_Msg_N
4633 Disc_Exp);
4635 -- All other cases are legal
4637 else
4642 ----------------------------
4643 -- In_Dispatching_Context --
4644 ----------------------------
4649 begin
4655 -- Start of processing for Resolve_Allocator
4657 begin
4658 -- Replace general access with specific type
4668 -- For qualified expression, resolve the expression using the given
4669 -- subtype (nothing to do for type mark, subtype indication)
4674 and then not In_Dispatching_Context
4675 then
4676 Error_Msg_N
4684 -- Allocators generated by the build-in-place expansion mechanism
4685 -- are explicitly marked as coming from source but do not need to be
4686 -- checked for limited initialization. To exclude this case, ensure
4687 -- that the parent of the allocator is a source node.
4692 and then not In_Instance_Body
4693 then
4700 -- A qualified expression requires an exact match of the type.
4701 -- Class-wide matching is not allowed.
4706 then
4710 -- Calls to build-in-place functions are not currently supported in
4711 -- allocators for access types associated with a simple storage pool.
4712 -- Supporting such allocators may require passing additional implicit
4713 -- parameters to build-in-place functions (or a significant revision
4714 -- of the current b-i-p implementation to unify the handling for
4715 -- multiple kinds of storage pools). ???
4719 then
4720 declare
4723 begin
4725 and then
4726 Present (Get_Rep_Pragma
4728 then
4729 Error_Msg_N
4736 -- A special accessibility check is needed for allocators that
4737 -- constrain access discriminants. The level of the type of the
4738 -- expression used to constrain an access discriminant cannot be
4739 -- deeper than the type of the allocator (in contrast to access
4740 -- parameters, where the level of the actual can be arbitrary).
4742 -- We can't use Valid_Conversion to perform this check because in
4743 -- general the type of the allocator is unrelated to the type of
4744 -- the access discriminant.
4748 then
4755 then
4758 -- Get the first component expression of the aggregate
4768 else
4772 else
4791 else
4796 else
4805 -- For a subtype mark or subtype indication, freeze the subtype
4807 else
4811 Error_Msg_N
4815 -- A special accessibility check is needed for allocators that
4816 -- constrain access discriminants. The level of the type of the
4817 -- expression used to constrain an access discriminant cannot be
4818 -- deeper than the type of the allocator (in contrast to access
4819 -- parameters, where the level of the actual can be arbitrary).
4820 -- We can't use Valid_Conversion to perform this check because
4821 -- in general the type of the allocator is unrelated to the type
4822 -- of the access discriminant.
4827 then
4837 else
4851 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4852 -- check that the level of the type of the created object is not deeper
4853 -- than the level of the allocator's access type, since extensions can
4854 -- now occur at deeper levels than their ancestor types. This is a
4855 -- static accessibility level check; a run-time check is also needed in
4856 -- the case of an initialized allocator with a class-wide argument (see
4857 -- Expand_Allocator_Expression).
4861 then
4862 declare
4865 begin
4870 else
4876 then
4879 Error_Msg_N
4888 -- Do not apply Ada 2005 accessibility checks on a class-wide
4889 -- allocator if the type given in the allocator is a formal
4890 -- type. A run-time check will be performed in the instance.
4900 -- Check for allocation from an empty storage pool
4905 -- If the context is an unchecked conversion, as may happen within an
4906 -- inlined subprogram, the allocator is being resolved with its own
4907 -- anonymous type. In that case, if the target type has a specific
4908 -- storage pool, it must be inherited explicitly by the allocator type.
4912 then
4913 Set_Associated_Storage_Pool
4921 -- Check that an allocator with task parts isn't for a nested access
4922 -- type when restriction No_Task_Hierarchy applies.
4926 then
4930 -- An illegal allocator may be rewritten as a raise Program_Error
4931 -- statement.
4935 -- An anonymous access discriminant is the definition of a
4936 -- coextension.
4940 N_Discriminant_Specification
4941 then
4942 declare
4946 begin
4949 -- Ada 2012 AI05-0052: If the designated type of the allocator
4950 -- is limited, then the allocator shall not be used to define
4951 -- the value of an access discriminant unless the discriminated
4952 -- type is immutably limited.
4957 then
4958 Error_Msg_N
4964 -- Avoid marking an allocator as a dynamic coextension if it is
4965 -- within a static construct.
4971 -- Cleanup for potential static coextensions
4973 else
4979 -- Report a simple error: if the designated object is a local task,
4980 -- its body has not been seen yet, and its activation will fail an
4981 -- elaboration check.
4988 then
4994 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4995 -- type with a task component on a subpool. This action must raise
4996 -- Program_Error at runtime.
5002 then
5014 ---------------------------
5015 -- Resolve_Arithmetic_Op --
5016 ---------------------------
5018 -- Used for resolving all arithmetic operators except exponentiation
5029 -- We do the resolution using the base type, because intermediate values
5030 -- in expressions always are of the base type, not a subtype of it.
5033 -- Returns True if N is in a context that expects "any real type"
5036 -- Return True iff given type is Integer or universal real/integer
5039 -- Choose type of integer literal in fixed-point operation to conform
5040 -- to available fixed-point type. T is the type of the other operand,
5041 -- which is needed to determine the expected type of N.
5044 -- Set operand type to T if universal
5046 -------------------------------
5047 -- Expected_Type_Is_Any_Real --
5048 -------------------------------
5051 begin
5052 -- N is the expression after "delta" in a fixed_point_definition;
5053 -- see RM-3.5.9(6):
5056 N_Decimal_Fixed_Point_Definition,
5058 -- N is one of the bounds in a real_range_specification;
5059 -- see RM-3.5.7(5):
5061 N_Real_Range_Specification,
5063 -- N is the expression of a delta_constraint;
5064 -- see RM-J.3(3):
5066 N_Delta_Constraint);
5069 -----------------------------
5070 -- Is_Integer_Or_Universal --
5071 -----------------------------
5078 begin
5084 else
5090 then
5101 ----------------------------
5102 -- Set_Mixed_Mode_Operand --
5103 ----------------------------
5109 begin
5112 -- A universal integer literal is resolved as standard integer
5113 -- except in the case of a fixed-point result, where we leave it
5114 -- as universal (to be handled by Exp_Fixd later on)
5118 else
5126 then
5127 -- A universal real can appear in a fixed-type context. We resolve
5128 -- the literal with that context, even though this might raise an
5129 -- exception prematurely (the other operand may be zero).
5136 then
5137 -- Integer arg in mixed-mode operation. Resolve with universal
5138 -- type, in case preference rule must be applied.
5144 then
5145 -- Not a mixed-mode operation, resolve with context
5151 -- N may itself be a mixed-mode operation, so use context type
5158 then
5159 -- Must be (fixed * fixed) operation, operand must have one
5160 -- compatible interpretation.
5167 then
5168 -- C * F(X) in a fixed context, where C is a real literal or a
5169 -- fixed-point expression. F must have either a fixed type
5170 -- interpretation or an integer interpretation, but not both.
5177 else
5184 else
5192 -- Reanalyze the literal with the fixed type of the context. If
5193 -- context is Universal_Fixed, we are within a conversion, leave
5194 -- the literal as a universal real because there is no usable
5195 -- fixed type, and the target of the conversion plays no role in
5196 -- the resolution.
5198 declare
5202 begin
5205 else
5211 then
5213 else
5221 else
5226 ----------------------
5227 -- Set_Operand_Type --
5228 ----------------------
5231 begin
5234 then
5239 -- Start of processing for Resolve_Arithmetic_Op
5241 begin
5246 then
5250 -- Special-case for mixed-mode universal expressions or fixed point type
5251 -- operation: each argument is resolved separately. The same treatment
5252 -- is required if one of the operands of a fixed point operation is
5253 -- universal real, since in this case we don't do a conversion to a
5254 -- specific fixed-point type (instead the expander handles the case).
5256 -- Set the type of the node to its universal interpretation because
5257 -- legality checks on an exponentiation operand need the context.
5262 then
5273 or else
5276 then
5281 -- If context is a fixed type and one operand is integer, the other
5282 -- is resolved with the type of the context.
5287 then
5294 then
5298 else
5303 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5304 -- multiplying operators from being used when the expected type is
5305 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5306 -- some cases where the expected type is actually Any_Real;
5307 -- Expected_Type_Is_Any_Real takes care of that case.
5311 then
5315 N_Unchecked_Type_Conversion)
5316 then
5323 else
5326 and then not
5328 N_Unchecked_Type_Conversion)
5329 then
5330 Error_Msg_N
5335 -- The expected type is "any real type" in contexts like
5337 -- type T is delta <universal_fixed-expression> ...
5339 -- in which case we need to set the type to Universal_Real
5340 -- so that static expression evaluation will work properly.
5344 else
5354 then
5359 -- If no previous errors, this is only possible if one operand is
5360 -- overloaded and the context is universal. Resolve as such.
5365 else
5367 and then
5369 then
5373 -- If the context is Universal_Fixed and the operands are also
5374 -- universal fixed, this is an error, unless there is only one
5375 -- applicable fixed_point type (usually Duration).
5383 else
5388 else
5393 -- If one of the arguments was resolved to a non-universal type.
5394 -- label the result of the operation itself with the same type.
5395 -- Do the same for the universal argument, if any.
5407 -- In SPARK, a multiplication or division with operands of fixed point
5408 -- types must be qualified or explicitly converted to identify the
5409 -- result type.
5414 and then
5416 then
5417 Check_SPARK_05_Restriction
5421 -- Set overflow and division checking bit
5428 -- Give warning if explicit division by zero
5432 then
5438 or else
5441 then
5442 -- Specialize the warning message according to the operation.
5443 -- The following warnings are for the case
5448 -- For division, we have two cases, for float division
5449 -- of an unconstrained float type, on a machine where
5450 -- Machine_Overflows is false, we don't get an exception
5451 -- at run-time, but rather an infinity or Nan. The Nan
5452 -- case is pretty obscure, so just warn about infinities.
5456 and then not Machine_Overflows_On_Target
5457 then
5458 Error_Msg_N
5462 -- For all other cases, we get a Constraint_Error
5464 else
5465 Apply_Compile_Time_Constraint_Error
5471 Apply_Compile_Time_Constraint_Error
5476 Apply_Compile_Time_Constraint_Error
5480 -- Division by zero can only happen with division, rem,
5481 -- and mod operations.
5487 -- Otherwise just set the flag to check at run time
5489 else
5494 -- If Restriction No_Implicit_Conditionals is active, then it is
5495 -- violated if either operand can be negative for mod, or for rem
5496 -- if both operands can be negative.
5500 then
5501 declare
5508 -- Set if corresponding operand might be negative
5510 begin
5511 Determine_Range
5515 Determine_Range
5519 -- Check if we will be generating conditionals. There are two
5520 -- cases where that can happen, first for REM, the only case
5521 -- is largest negative integer mod -1, where the division can
5522 -- overflow, but we still have to give the right result. The
5523 -- front end generates a test for this annoying case. Here we
5524 -- just test if both operands can be negative (that's what the
5525 -- expander does, so we match its logic here).
5527 -- The second case is mod where either operand can be negative.
5528 -- In this case, the back end has to generate additional tests.
5531 or else
5533 then
5544 ------------------
5545 -- Resolve_Call --
5546 ------------------
5549 function Same_Or_Aliased_Subprograms
5552 -- Returns True if the subprogram entity S is the same as E or else
5553 -- S is an alias of E.
5555 ---------------------------------
5556 -- Same_Or_Aliased_Subprograms --
5557 ---------------------------------
5559 function Same_Or_Aliased_Subprograms
5562 is
5564 begin
5568 -- Local variables
5582 -- Start of processing for Resolve_Call
5584 begin
5585 -- The context imposes a unique interpretation with type Typ on a
5586 -- procedure or function call. Find the entity of the subprogram that
5587 -- yields the expected type, and propagate the corresponding formal
5588 -- constraints on the actuals. The caller has established that an
5589 -- interpretation exists, and emitted an error if not unique.
5591 -- First deal with the case of a call to an access-to-subprogram,
5592 -- dereference made explicit in Analyze_Call.
5598 else
5599 -- Find the interpretation whose type (a subprogram type) has a
5600 -- return type that is compatible with the context. Analysis of
5601 -- the node has established that one exists.
5620 -- If the prefix is not an entity, then resolve it
5626 -- For an indirect call, we always invalidate checks, since we do not
5627 -- know whether the subprogram is local or global. Yes we could do
5628 -- better here, e.g. by knowing that there are no local subprograms,
5629 -- but it does not seem worth the effort. Similarly, we kill all
5630 -- knowledge of current constant values.
5632 Kill_Current_Values;
5634 -- If this is a procedure call which is really an entry call, do
5635 -- the conversion of the procedure call to an entry call. Protected
5636 -- operations use the same circuitry because the name in the call
5637 -- can be an arbitrary expression with special resolution rules.
5642 then
5646 -- Kill checks and constant values, as above for indirect case
5647 -- Who knows what happens when another task is activated?
5649 Kill_Current_Values;
5652 -- Normal subprogram call with name established in Resolve
5658 -- Otherwise we must have the case of an overloaded call
5660 else
5663 -- Initialize Nam to prevent warning (we know it will be assigned
5664 -- in the loop below, but the compiler does not know that).
5684 then
5685 -- The prefix is a parameterless function call that returns an access
5686 -- to subprogram. If parameters are present in the current call, add
5687 -- add an explicit dereference. We use the base type here because
5688 -- within an instance these may be subtypes.
5690 -- The dereference is added either in Analyze_Call or here. Should
5691 -- be consolidated ???
5700 -- Check that a call to Current_Task does not occur in an entry body
5703 declare
5706 begin
5708 loop
5711 -- Exclude calls that occur within the default of a formal
5712 -- parameter of the entry, since those are evaluated outside
5713 -- of the body.
5720 then
5723 Error_Msg_NE
5737 -- Check that a procedure call does not occur in the context of the
5738 -- entry call statement of a conditional or timed entry call. Note that
5739 -- the case of a call to a subprogram renaming of an entry will also be
5740 -- rejected. The test for N not being an N_Entry_Call_Statement is
5741 -- defensive, covering the possibility that the processing of entry
5742 -- calls might reach this point due to later modifications of the code
5743 -- above.
5748 then
5752 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5753 -- for a procedure_or_entry_call, the procedure_name or
5754 -- procedure_prefix of the procedure_call_statement shall denote
5755 -- an entry renamed by a procedure, or (a view of) a primitive
5756 -- subprogram of a limited interface whose first parameter is
5757 -- a controlling parameter.
5762 then
5763 Error_Msg_N
5768 -- If the SPARK_05 restriction is active, we are not allowed
5769 -- to have a call to a subprogram before we see its completion.
5774 -- Don't flag strange internal calls
5779 -- Only flag calls in extended main source
5784 -- Exclude enumeration literals from this processing
5787 then
5788 Check_SPARK_05_Restriction
5792 -- Check that this is not a call to a protected procedure or entry from
5793 -- within a protected function.
5797 -- Freeze the subprogram name if not in a spec-expression. Note that
5798 -- we freeze procedure calls as well as function calls. Procedure calls
5799 -- are not frozen according to the rules (RM 13.14(14)) because it is
5800 -- impossible to have a procedure call to a non-frozen procedure in
5801 -- pure Ada, but in the code that we generate in the expander, this
5802 -- rule needs extending because we can generate procedure calls that
5803 -- need freezing.
5805 -- In Ada 2012, expression functions may be called within pre/post
5806 -- conditions of subsequent functions or expression functions. Such
5807 -- calls do not freeze when they appear within generated bodies,
5808 -- (including the body of another expression function) which would
5809 -- place the freeze node in the wrong scope. An expression function
5810 -- is frozen in the usual fashion, by the appearance of a real body,
5811 -- or at the end of a declarative part.
5814 and then not In_Spec_Expression
5816 and then
5819 then
5823 -- For a predefined operator, the type of the result is the type imposed
5824 -- by context, except for a predefined operation on universal fixed.
5825 -- Otherwise The type of the call is the type returned by the subprogram
5826 -- being called.
5833 -- If the subprogram returns an array type, and the context requires the
5834 -- component type of that array type, the node is really an indexing of
5835 -- the parameterless call. Resolve as such. A pathological case occurs
5836 -- when the type of the component is an access to the array type. In
5837 -- this case the call is truly ambiguous.
5840 and then
5843 or else
5846 and then
5848 then
5849 declare
5854 begin
5857 then
5858 Error_Msg_N
5860 else
5863 -- The called entity may be an explicit dereference, in which
5864 -- case there is no entity to set.
5872 or else
5874 and then
5876 then
5879 -- Indexed call to a parameterless function
5881 Index_Node :=
5883 Prefix =>
5886 else
5887 -- An Ada 2005 prefixed call to a primitive operation
5888 -- whose first parameter is the prefix. This prefix was
5889 -- prepended to the parameter list, which is actually a
5890 -- list of indexes. Remove the prefix in order to build
5891 -- the proper indexed component.
5893 Index_Node :=
5895 Prefix =>
5898 Parameter_Associations =>
5899 New_List
5904 -- Preserve the parenthesis count of the node
5908 -- Since we are correcting a node classification error made
5909 -- by the parser, we call Replace rather than Rewrite.
5923 else
5927 -- In the case where the call is to an overloaded subprogram, Analyze
5928 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5929 -- such a case Normalize_Actuals needs to be called once more to order
5930 -- the actuals correctly. Otherwise the call will have the ordering
5931 -- given by the last overloaded subprogram whether this is the correct
5932 -- one being called or not.
5939 -- In any case, call is fully resolved now. Reset Overload flag, to
5940 -- prevent subsequent overload resolution if node is analyzed again
5945 -- A Ghost entity must appear in a specific context
5951 -- If we are calling the current subprogram from immediately within its
5952 -- body, then that is the case where we can sometimes detect cases of
5953 -- infinite recursion statically. Do not try this in case restriction
5954 -- No_Recursion is in effect anyway, and do it only for source calls.
5959 -- Check violation of SPARK_05 restriction which does not permit
5960 -- a subprogram body to contain a call to the subprogram directly.
5964 then
5965 Check_SPARK_05_Restriction
5969 -- Issue warning for possible infinite recursion in the absence
5970 -- of the No_Recursion restriction.
5975 then
5976 -- Here we detected and flagged an infinite recursion, so we do
5977 -- not need to test the case below for further warnings. Also we
5978 -- are all done if we now have a raise SE node.
5984 -- If call is to immediately containing subprogram, then check for
5985 -- the case of a possible run-time detectable infinite recursion.
5987 else
5991 -- Although in general case, recursion is not statically
5992 -- checkable, the case of calling an immediately containing
5993 -- subprogram is easy to catch.
5997 -- If the recursive call is to a parameterless subprogram,
5998 -- then even if we can't statically detect infinite
5999 -- recursion, this is pretty suspicious, and we output a
6000 -- warning. Furthermore, we will try later to detect some
6001 -- cases here at run time by expanding checking code (see
6002 -- Detect_Infinite_Recursion in package Exp_Ch6).
6004 -- If the recursive call is within a handler, do not emit a
6005 -- warning, because this is a common idiom: loop until input
6006 -- is correct, catch illegal input in handler and restart.
6012 then
6013 -- For the case of a procedure call. We give the message
6014 -- only if the call is the first statement in a sequence
6015 -- of statements, or if all previous statements are
6016 -- simple assignments. This is simply a heuristic to
6017 -- decrease false positives, without losing too many good
6018 -- warnings. The idea is that these previous statements
6019 -- may affect global variables the procedure depends on.
6020 -- We also exclude raise statements, that may arise from
6021 -- constraint checks and are probably unrelated to the
6022 -- intended control flow.
6026 then
6027 declare
6029 begin
6033 N_Raise_Constraint_Error)
6034 then
6043 -- Do not give warning if we are in a conditional context
6045 declare
6047 begin
6053 then
6058 -- Here warning is to be issued
6074 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6078 -- If subprogram name is a predefined operator, it was given in
6079 -- functional notation. Replace call node with operator node, so
6080 -- that actuals can be resolved appropriately.
6088 then
6094 -- Create a transient scope if the resulting type requires it
6096 -- There are several notable exceptions:
6098 -- a) In init procs, the transient scope overhead is not needed, and is
6099 -- even incorrect when the call is a nested initialization call for a
6100 -- component whose expansion may generate adjust calls. However, if the
6101 -- call is some other procedure call within an initialization procedure
6102 -- (for example a call to Create_Task in the init_proc of the task
6103 -- run-time record) a transient scope must be created around this call.
6105 -- b) Enumeration literal pseudo-calls need no transient scope
6107 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6108 -- functions) do not use the secondary stack even though the return
6109 -- type may be unconstrained.
6111 -- d) Calls to a build-in-place function, since such functions may
6112 -- allocate their result directly in a target object, and cases where
6113 -- the result does get allocated in the secondary stack are checked for
6114 -- within the specialized Exp_Ch6 procedures for expanding those
6115 -- build-in-place calls.
6117 -- e) If the subprogram is marked Inline_Always, then even if it returns
6118 -- an unconstrained type the call does not require use of the secondary
6119 -- stack. However, inlining will only take place if the body to inline
6120 -- is already present. It may not be available if e.g. the subprogram is
6121 -- declared in a child instance.
6123 -- If this is an initialization call for a type whose construction
6124 -- uses the secondary stack, and it is not a nested call to initialize
6125 -- a component, we do need to create a transient scope for it. We
6126 -- check for this by traversing the type in Check_Initialization_Call.
6132 then
6138 then
6141 elsif Expander_Active
6144 and then
6146 or else
6148 then
6151 -- If the call appears within the bounds of a loop, it will
6152 -- be rewritten and reanalyzed, nothing left to do here.
6159 and then not Within_Init_Proc
6160 then
6164 -- A protected function cannot be called within the definition of the
6165 -- enclosing protected type, unless it is part of a pre/postcondition
6166 -- on another protected operation.
6171 and then not In_Spec_Expression
6172 then
6173 Error_Msg_NE
6177 -- Propagate interpretation to actuals, and add default expressions
6178 -- where needed.
6183 -- Overloaded literals are rewritten as function calls, for purpose of
6184 -- resolution. After resolution, we can replace the call with the
6185 -- literal itself.
6191 -- Avoid validation, since it is a static function call
6197 -- If the subprogram is not global, then kill all saved values and
6198 -- checks. This is a bit conservative, since in many cases we could do
6199 -- better, but it is not worth the effort. Similarly, we kill constant
6200 -- values. However we do not need to do this for internal entities
6201 -- (unless they are inherited user-defined subprograms), since they
6202 -- are not in the business of molesting local values.
6204 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6205 -- kill all checks and values for calls to global subprograms. This
6206 -- takes care of the case where an access to a local subprogram is
6207 -- taken, and could be passed directly or indirectly and then called
6208 -- from almost any context.
6210 -- Note: we do not do this step till after resolving the actuals. That
6211 -- way we still take advantage of the current value information while
6212 -- scanning the actuals.
6214 -- We suppress killing values if we are processing the nodes associated
6215 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6216 -- type kills all the values as part of analyzing the code that
6217 -- initializes the dispatch tables.
6221 or else Suppress_Value_Tracking_On_Call
6226 then
6227 Kill_Current_Values;
6230 -- If we are warning about unread OUT parameters, this is the place to
6231 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6232 -- after the above call to Kill_Current_Values (since that call clears
6233 -- the Last_Assignment field of all local variables).
6238 then
6239 declare
6243 begin
6253 then
6263 -- If the subprogram is a primitive operation, check whether or not
6264 -- it is a correct dispatching call.
6268 then
6273 and then not In_Instance
6274 then
6278 -- If this is a dispatching call, generate the appropriate reference,
6279 -- for better source navigation in GPS.
6283 then
6286 -- Normal case, not a dispatching call: generate a call reference
6288 else
6296 -- Check for violation of restriction No_Specific_Termination_Handlers
6297 -- and warn on a potentially blocking call to Abort_Task.
6301 or else
6303 then
6310 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6311 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6312 -- need to check the second argument to determine whether it is an
6313 -- absolute or relative timing event.
6318 then
6322 -- Issue an error for a call to an eliminated subprogram. This routine
6323 -- will not perform the check if the call appears within a default
6324 -- expression.
6328 -- In formal mode, the primitive operations of a tagged type or type
6329 -- extension do not include functions that return the tagged type.
6335 then
6339 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6340 -- class-wide and the call dispatches on result in a context that does
6341 -- not provide a tag, the call raises Program_Error.
6344 and then In_Instance
6349 then
6350 -- Verify that none of the formals are controlling
6352 declare
6356 begin
6378 -- Check for calling a function with OUT or IN OUT parameter when the
6379 -- calling context (us right now) is not Ada 2012, so does not allow
6380 -- OUT or IN OUT parameters in function calls. Functions declared in
6381 -- a predefined unit are OK, as they may be called indirectly from a
6382 -- user-declared instantiation.
6388 then
6393 -- Check the dimensions of the actuals in the call. For function calls,
6394 -- propagate the dimensions from the returned type to N.
6398 -- All done, evaluate call and deal with elaboration issues
6403 -- In GNATprove mode, expansion is disabled, but we want to inline some
6404 -- subprograms to facilitate formal verification. Indirect calls through
6405 -- a subprogram type or within a generic cannot be inlined. Inlining is
6406 -- performed only for calls subject to SPARK_Mode on.
6408 if GNATprove_Mode
6411 and then not Inside_A_Generic
6412 then
6419 -- Nothing to do if the subprogram is not eligible for inlining in
6420 -- GNATprove mode.
6424 then
6427 -- Calls cannot be inlined inside assertions, as GNATprove treats
6428 -- assertions as logic expressions.
6435 -- Calls cannot be inlined inside default expressions
6442 -- Inlining should not be performed during pre-analysis
6446 -- With the one-pass inlining technique, a call cannot be
6447 -- inlined if the corresponding body has not been seen yet.
6450 Error_Msg_NE
6455 -- Nothing to do if there is no body to inline, indicating that
6456 -- the subprogram is not suitable for inlining in GNATprove
6457 -- mode.
6462 -- Calls cannot be inlined inside potentially unevaluated
6463 -- expressions, as this would create complex actions inside
6464 -- expressions, that are not handled by GNATprove.
6468 Error_Msg_N
6472 -- Otherwise, inline the call
6474 else
6484 -----------------------------
6485 -- Resolve_Case_Expression --
6486 -----------------------------
6492 begin
6499 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6500 -- dynamically tagged must be known statically.
6520 -------------------------------
6521 -- Resolve_Character_Literal --
6522 -------------------------------
6528 begin
6529 -- Verify that the character does belong to the type of the context
6534 -- Wide_Wide_Character literals must always be defined, since the set
6535 -- of wide wide character literals is complete, i.e. if a character
6536 -- literal is accepted by the parser, then it is OK for wide wide
6537 -- character (out of range character literals are rejected).
6542 -- Always accept character literal for type Any_Character, which
6543 -- occurs in error situations and in comparisons of literals, both
6544 -- of which should accept all literals.
6549 -- For Standard.Character or a type derived from it, check that the
6550 -- literal is in range.
6557 -- For Standard.Wide_Character or a type derived from it, check that the
6558 -- literal is in range.
6565 -- For Standard.Wide_Wide_Character or a type derived from it, we
6566 -- know the literal is in range, since the parser checked.
6571 -- If the entity is already set, this has already been resolved in a
6572 -- generic context, or comes from expansion. Nothing else to do.
6577 -- Otherwise we have a user defined character type, and we can use the
6578 -- standard visibility mechanisms to locate the referenced entity.
6580 else
6593 -- If we fall through, then the literal does not match any of the
6594 -- entries of the enumeration type. This isn't just a constraint error
6595 -- situation, it is an illegality (see RM 4.2).
6597 Error_Msg_NE
6601 ---------------------------
6602 -- Resolve_Comparison_Op --
6603 ---------------------------
6605 -- Context requires a boolean type, and plays no role in resolution.
6606 -- Processing identical to that for equality operators. The result type is
6607 -- the base type, which matters when pathological subtypes of booleans with
6608 -- limited ranges are used.
6615 begin
6616 -- If this is an intrinsic operation which is not predefined, use the
6617 -- types of its declared arguments to resolve the possibly overloaded
6618 -- operands. Otherwise the operands are unambiguous and specify the
6619 -- expected type.
6624 else
6635 -- Skip remaining processing if already set to Any_Type
6641 -- Deal with other error cases
6645 T = Any_Character
6646 then
6649 else
6657 -- Resolve the operands if types OK
6666 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6667 -- types or array types except String.
6670 Check_SPARK_05_Restriction
6675 then
6676 Check_SPARK_05_Restriction
6680 -- Check comparison on unordered enumeration
6684 Error_Msg_NE
6689 -- Evaluate the relation (note we do this after the above check since
6690 -- this Eval call may change N to True/False.
6696 -----------------------------------------
6697 -- Resolve_Discrete_Subtype_Indication --
6698 -----------------------------------------
6700 procedure Resolve_Discrete_Subtype_Indication
6703 is
6707 begin
6715 else
6725 Error_Msg_NE
6728 -- Rewrite the constraint as a range of Typ
6729 -- to allow compilation to proceed further.
6741 else
6745 -- Additionally, we must check that the bounds are compatible
6746 -- with the given subtype, which might be different from the
6747 -- type of the context.
6751 -- ??? If the above check statically detects a Constraint_Error
6752 -- it replaces the offending bound(s) of the range R with a
6753 -- Constraint_Error node. When the itype which uses these bounds
6754 -- is frozen the resulting call to Duplicate_Subexpr generates
6755 -- a new temporary for the bounds.
6757 -- Unfortunately there are other itypes that are also made depend
6758 -- on these bounds, so when Duplicate_Subexpr is called they get
6759 -- a forward reference to the newly created temporaries and Gigi
6760 -- aborts on such forward references. This is probably sign of a
6761 -- more fundamental problem somewhere else in either the order of
6762 -- itype freezing or the way certain itypes are constructed.
6764 -- To get around this problem we call Remove_Side_Effects right
6765 -- away if either bounds of R are a Constraint_Error.
6767 declare
6771 begin
6787 -------------------------
6788 -- Resolve_Entity_Name --
6789 -------------------------
6791 -- Used to resolve identifiers and expanded names
6794 function Is_Assignment_Or_Object_Expression
6797 -- Determine whether node Context denotes an assignment statement or an
6798 -- object declaration whose expression is node Expr.
6800 function Is_OK_Volatile_Context
6803 -- Determine whether node Context denotes a "non-interfering context"
6804 -- (as defined in SPARK RM 7.1.3(12)) where volatile reference Obj_Ref
6805 -- can safely reside.
6807 ----------------------------------------
6808 -- Is_Assignment_Or_Object_Expression --
6809 ----------------------------------------
6811 function Is_Assignment_Or_Object_Expression
6814 is
6815 begin
6817 N_Object_Declaration)
6819 then
6822 -- Check whether a construct that yields a name is the expression of
6823 -- an assignment statement or an object declaration.
6826 N_Explicit_Dereference,
6827 N_Indexed_Component,
6828 N_Selected_Component,
6829 N_Slice)
6831 or else
6833 N_Unchecked_Type_Conversion)
6835 then
6836 return
6837 Is_Assignment_Or_Object_Expression
6841 -- Otherwise the context is not an assignment statement or an object
6842 -- declaration.
6844 else
6849 ----------------------------
6850 -- Is_OK_Volatile_Context --
6851 ----------------------------
6853 function Is_OK_Volatile_Context
6856 is
6858 -- Determine whether an arbitrary node denotes a call to a protected
6859 -- entry, function or procedure in prefixed form where the prefix is
6860 -- Obj_Ref.
6863 -- Determine whether an arbitrary node appears in a check node
6866 -- Determine whether an arbitrary node appears in a procedure call
6869 -- Determine whether an arbitrary entity appears in a volatile
6870 -- function.
6872 ---------------------------------
6873 -- Is_Protected_Operation_Call --
6874 ---------------------------------
6880 begin
6881 -- A call to a protected operations retains its selected component
6882 -- form as opposed to other prefixed calls that are transformed in
6883 -- expanded names.
6889 return
6890 Pref = Obj_Ref
6894 E_Entry_Family,
6895 E_Function,
6896 E_Procedure);
6897 else
6902 ------------------
6903 -- Within_Check --
6904 ------------------
6909 begin
6910 -- Climb the parent chain looking for a check node
6917 -- Prevent the search from going too far
6929 ----------------------------
6930 -- Within_Subprogram_Call --
6931 ----------------------------
6936 begin
6937 -- Climb the parent chain looking for a function or procedure call
6942 N_Procedure_Call_Statement)
6943 then
6946 -- Prevent the search from going too far
6958 ------------------------------
6959 -- Within_Volatile_Function --
6960 ------------------------------
6965 begin
6966 -- Traverse the scope stack looking for a [generic] function
6980 -- Local variables
6984 -- Start of processing for Is_OK_Volatile_Context
6986 begin
6987 -- The volatile object appears on either side of an assignment
6992 -- The volatile object is part of the initialization expression of
6993 -- another object.
6998 then
7001 -- The volatile object acts as the initialization expression of an
7002 -- extended return statement. This is valid context as long as the
7003 -- function is volatile.
7008 -- Otherwise this is a normal object initialization
7010 else
7014 -- The volatile object acts as the name of a renaming declaration
7018 then
7021 -- The volatile object appears as an actual parameter in a call to an
7022 -- instance of Unchecked_Conversion whose result is renamed.
7028 then
7031 -- The volatile object is actually the prefix in a protected entry,
7032 -- function, or procedure call.
7037 -- The volatile object appears as the expression of a simple return
7038 -- statement that applies to a volatile function.
7042 then
7043 return
7046 -- The volatile object appears as the prefix of a name occurring
7047 -- in a non-interfering context.
7050 N_Explicit_Dereference,
7051 N_Indexed_Component,
7052 N_Selected_Component,
7053 N_Slice)
7055 and then Is_OK_Volatile_Context
7058 then
7061 -- The volatile object appears as the expression of a type conversion
7062 -- occurring in a non-interfering context.
7065 N_Unchecked_Type_Conversion)
7067 and then Is_OK_Volatile_Context
7070 then
7073 -- Allow references to volatile objects in various checks. This is
7074 -- not a direct SPARK 2014 requirement.
7079 -- Assume that references to effectively volatile objects that appear
7080 -- as actual parameters in a subprogram call are always legal. A full
7081 -- legality check is done when the actuals are resolved.
7086 -- Otherwise the context is not suitable for an effectively volatile
7087 -- object.
7089 else
7094 -- Local variables
7099 -- Start of processing for Resolve_Entity_Name
7101 begin
7102 -- If garbage from errors, set to Any_Type and return
7109 -- Replace named numbers by corresponding literals. Note that this is
7110 -- the one case where Resolve_Entity_Name must reset the Etype, since
7111 -- it is currently marked as universal.
7121 -- For enumeration literals, we need to make sure that a proper style
7122 -- check is done, since such literals are overloaded, and thus we did
7123 -- not do a style check during the first phase of analysis.
7129 -- Case of (sub)type name appearing in a context where an expression
7130 -- is expected. This is legal if occurrence is a current instance.
7131 -- See RM 8.6 (17/3).
7137 -- Any other use is an error
7139 else
7140 Error_Msg_N
7144 -- Check discriminant use if entity is discriminant in current scope,
7145 -- i.e. discriminant of record or concurrent type currently being
7146 -- analyzed. Uses in corresponding body are unrestricted.
7151 then
7154 -- A parameterless generic function cannot appear in a context that
7155 -- requires resolution.
7160 -- In Ada 83 an OUT parameter cannot be read
7165 or else Is_Assignment_Or_Object_Expression
7168 then
7173 -- In all other cases, just do the possible static evaluation
7175 else
7176 -- A deferred constant that appears in an expression must have a
7177 -- completion, unless it has been removed by in-place expansion of
7178 -- an aggregate. A constant that is a renaming does not need
7179 -- initialization.
7185 and then not In_Spec_Expression
7188 then
7192 then
7194 else
7195 Error_Msg_N (
7205 -- When the entity appears in a parameter association, retrieve the
7206 -- related subprogram call.
7214 -- The following checks are only relevant when SPARK_Mode is on as
7215 -- they are not standard Ada legality rules.
7219 -- An effectively volatile object subject to enabled properties
7220 -- Async_Writers or Effective_Reads must appear in non-interfering
7221 -- context (SPARK RM 7.1.3(12)).
7228 then
7229 SPARK_Msg_N
7234 -- Check for possible elaboration issues with respect to reads of
7235 -- variables. The act of renaming the variable is not considered a
7236 -- read as it simply establishes an alias.
7240 then
7244 -- The variable may eventually become a constituent of a single
7245 -- protected/task type. Record the reference now and verify its
7246 -- legality when analyzing the contract of the variable
7247 -- (SPARK RM 9.3).
7254 -- A Ghost entity must appear in a specific context
7262 -------------------
7263 -- Resolve_Entry --
7264 -------------------
7276 -- If the bounds of the entry family being called depend on task
7277 -- discriminants, build a new index subtype where a discriminant is
7278 -- replaced with the value of the discriminant of the target task.
7279 -- The target task is the prefix of the entry name in the call.
7281 -----------------------
7282 -- Actual_Index_Type --
7283 -----------------------
7293 -- If the bound is given by a discriminant, replace with a reference
7294 -- to the discriminant of the same name in the target task. If the
7295 -- entry name is the target of a requeue statement and the entry is
7296 -- in the current protected object, the bound to be used is the
7297 -- discriminal of the object (see Apply_Range_Checks for details of
7298 -- the transformation).
7300 -----------------------------
7301 -- Actual_Discriminant_Ref --
7302 -----------------------------
7308 begin
7313 then
7319 then
7320 -- Note: here Bound denotes a discriminant of the corresponding
7321 -- record type tskV, whose discriminal is a formal of the
7322 -- init-proc tskVIP. What we want is the body discriminal,
7323 -- which is associated to the discriminant of the original
7324 -- concurrent type tsk.
7326 return New_Occurrence_Of
7329 else
7330 Ref :=
7340 -- Start of processing for Actual_Index_Type
7342 begin
7345 then
7348 else
7362 -- Start of processing for Resolve_Entry
7364 begin
7365 -- Find name of entry being called, and resolve prefix of name with its
7366 -- own type. The prefix can be overloaded, and the name and signature of
7367 -- the entry must be taken into account.
7371 -- Case of dealing with entry family within the current tasks
7375 else
7381 -- Entry call to an entry (or entry family) in the current task. This
7382 -- is legal even though the task will deadlock. Rewrite as call to
7383 -- current task.
7385 -- This can also be a call to an entry in an enclosing task. If this
7386 -- is a single task, we have to retrieve its name, because the scope
7387 -- of the entry is the task type, not the object. If the enclosing
7388 -- task is a task type, the identity of the task is given by its own
7389 -- self variable.
7391 -- Finally this can be a requeue on an entry of the same task or
7392 -- protected object.
7399 then
7400 -- S is an enclosing task or protected object. The concurrent
7401 -- declaration has been converted into a type declaration, and
7402 -- the object itself has an object declaration that follows
7403 -- the type in the same declarative part.
7415 -- Call to current task. Will be transformed into call to Self
7422 New_N :=
7425 Selector_Name =>
7432 then
7433 -- Use the entry name (which must be unique at this point) to find
7434 -- the prefix that returns the corresponding task/protected type.
7436 declare
7442 begin
7464 -- Up to this point the expression could have been the actual in a
7465 -- simple entry call, and be given by a named association.
7469 else
7475 ------------------------
7476 -- Resolve_Entry_Call --
7477 ------------------------
7489 begin
7490 -- We kill all checks here, because it does not seem worth the effort to
7491 -- do anything better, an entry call is a big operation.
7493 Kill_All_Checks;
7495 -- Processing of the name is similar for entry calls and protected
7496 -- operation calls. Once the entity is determined, we can complete
7497 -- the resolution of the actuals.
7499 -- The selector may be overloaded, in the case of a protected object
7500 -- with overloaded functions. The type of the context is used for
7501 -- resolution.
7506 then
7507 declare
7511 begin
7530 -- Simple entry call
7538 -- Call to member of entry family
7545 -- We cannot in general check the maximum depth of protected entry calls
7546 -- at compile time. But we can tell that any protected entry call at all
7547 -- violates a specified nesting depth of zero.
7553 -- Use context type to disambiguate a protected function that can be
7554 -- called without actuals and that returns an array type, and where the
7555 -- argument list may be an indexing of the returned value.
7560 and then
7566 and then
7567 Covers
7570 then
7571 declare
7574 begin
7575 Index_Node :=
7577 Prefix =>
7581 -- Since we are correcting a node classification error made by the
7582 -- parser, we call Replace rather than Rewrite.
7595 then
7596 -- Rewrite as call to the precondition wrapper, adding the task
7597 -- object to the list of actuals. If the call is to a member of an
7598 -- entry family, include the index as well.
7600 declare
7604 begin
7613 New_Call :=
7615 Name =>
7620 -- Preanalyze and resolve new call. Current procedure is called
7621 -- from Resolve_Call, after which expansion will take place.
7628 -- The operation name may have been overloaded. Order the actuals
7629 -- according to the formals of the resolved entity, and set the return
7630 -- type to that of the operation.
7641 -- Create a call reference to the entry
7649 -- Verify that a procedure call cannot masquerade as an entry
7650 -- call where an entry call is expected.
7655 then
7660 then
7665 then
7670 -- After resolution, entry calls and protected procedure calls are
7671 -- changed into entry calls, for expansion. The structure of the node
7672 -- does not change, so it can safely be done in place. Protected
7673 -- function calls must keep their structure because they are
7674 -- subexpressions.
7678 -- A protected operation that is not a function may modify the
7679 -- corresponding object, and cannot apply to a constant. If this
7680 -- is an internal call, the prefix is the type itself.
7686 then
7687 Error_Msg_N
7689 Entry_Name);
7703 -- Protected functions can return on the secondary stack, in which
7704 -- case we must trigger the transient scope mechanism.
7706 elsif Expander_Active
7708 then
7713 -------------------------
7714 -- Resolve_Equality_Op --
7715 -------------------------
7717 -- Both arguments must have the same type, and the boolean context does
7718 -- not participate in the resolution. The first pass verifies that the
7719 -- interpretation is not ambiguous, and the type of the left argument is
7720 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7721 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7722 -- though they carry a single (universal) type. Diagnose this case here.
7730 -- The resolution rule for if expressions requires that each such must
7731 -- have a unique type. This means that if several dependent expressions
7732 -- are of a non-null anonymous access type, and the context does not
7733 -- impose an expected type (as can be the case in an equality operation)
7734 -- the expression must be rejected.
7737 -- Attempt to explain the nature of a redundant comparison with True. If
7738 -- the expression N is too complex, this routine issues a general error
7739 -- message.
7742 -- In the case of allocators and access attributes, the context must
7743 -- provide an indication of the specific access type to be used. If
7744 -- one operand is of such a "generic" access type, check whether there
7745 -- is a specific visible access type that has the same designated type.
7746 -- This is semantically dubious, and of no interest to any real code,
7747 -- but c48008a makes it all worthwhile.
7749 -------------------------
7750 -- Check_If_Expression --
7751 -------------------------
7757 begin
7764 then
7770 ------------------------
7771 -- Explain_Redundancy --
7772 ------------------------
7779 begin
7782 -- Strip the operand down to an entity
7784 loop
7787 else
7792 -- The construct denotes an entity
7797 -- Do not generate an error message when the comparison is done
7798 -- against the enumeration literal Standard.True.
7802 -- Build a customized error message
7829 -- The construct is too complex to disect, issue a general message
7831 else
7836 -----------------------------
7837 -- Find_Unique_Access_Type --
7838 -----------------------------
7845 begin
7847 E_Access_Attribute_Type)
7848 then
7852 E_Access_Attribute_Type)
7853 then
7855 else
7867 then
7880 -- Start of processing for Resolve_Equality_Op
7882 begin
7893 T = Any_Character
7894 then
7897 else
7906 then
7915 -- If expressions must have a single type, and if the context does
7916 -- not impose one the dependent expressions cannot be anonymous
7917 -- access types.
7919 -- Why no similar processing for case expressions???
7923 E_Anonymous_Access_Subprogram_Type)
7925 E_Anonymous_Access_Subprogram_Type)
7926 then
7934 -- In SPARK, equality operators = and /= for array types other than
7935 -- String are only defined when, for each index position, the
7936 -- operands have equal static bounds.
7940 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7941 -- operation if not needed.
7949 then
7950 Check_SPARK_05_Restriction
7955 -- If the unique type is a class-wide type then it will be expanded
7956 -- into a dispatching call to the predefined primitive. Therefore we
7957 -- check here for potential violation of such restriction.
7963 if Warn_On_Redundant_Constructs
7968 then
7969 Error_Msg_N -- CODEFIX
7979 -- If this is an inequality, it may be the implicit inequality
7980 -- created for a user-defined operation, in which case the corres-
7981 -- ponding equality operation is not intrinsic, and the operation
7982 -- cannot be constant-folded. Else fold.
7987 or else Is_Intrinsic_Subprogram
7989 then
7995 then
7999 -- Ada 2005: If one operand is an anonymous access type, convert the
8000 -- other operand to it, to ensure that the underlying types match in
8001 -- the back-end. Same for access_to_subprogram, and the conversion
8002 -- verifies that the types are subtype conformant.
8004 -- We apply the same conversion in the case one of the operands is a
8005 -- private subtype of the type of the other.
8007 -- Why the Expander_Active test here ???
8009 if Expander_Active
8010 and then
8012 E_Anonymous_Access_Subprogram_Type)
8014 then
8034 ----------------------------------
8035 -- Resolve_Explicit_Dereference --
8036 ----------------------------------
8044 -- The candidate prefix type, if overloaded
8049 begin
8053 -- A useful optimization: check whether the dereference denotes an
8054 -- element of a container, and if so rewrite it as a call to the
8055 -- corresponding Element function.
8057 -- Disabled for now, on advice of ARG. A more restricted form of the
8058 -- predicate might be acceptable ???
8060 -- if Is_Container_Element (N) then
8061 -- return;
8062 -- end if;
8066 -- Use the context type to select the prefix that has the correct
8067 -- designated type. Keep the first match, which will be the inner-
8068 -- most.
8075 then
8080 -- Remove access types that do not match, but preserve access
8081 -- to subprogram interpretations, in case a further dereference
8082 -- is needed (see below).
8095 else
8096 -- If no interpretation covers the designated type of the prefix,
8097 -- this is the pathological case where not all implementations of
8098 -- the prefix allow the interpretation of the node as a call. Now
8099 -- that the expected type is known, Remove other interpretations
8100 -- from prefix, rewrite it as a call, and resolve again, so that
8101 -- the proper call node is generated.
8112 New_N :=
8114 Name =>
8125 -- If not overloaded, resolve P with its own type
8127 else
8131 -- If the prefix might be null, add an access check
8135 then
8139 -- If the designated type is a packed unconstrained array type, and the
8140 -- explicit dereference is not in the context of an attribute reference,
8141 -- then we must compute and set the actual subtype, since it is needed
8142 -- by Gigi. The reason we exclude the attribute case is that this is
8143 -- handled fine by Gigi, and in fact we use such attributes to build the
8144 -- actual subtype. We also exclude generated code (which builds actual
8145 -- subtypes directly if they are needed).
8152 then
8158 -- Note: No Eval processing is required for an explicit dereference,
8159 -- because such a name can never be static.
8163 -------------------------------------
8164 -- Resolve_Expression_With_Actions --
8165 -------------------------------------
8168 begin
8171 -- If N has no actions, and its expression has been constant folded,
8172 -- then rewrite N as just its expression. Note, we can't do this in
8173 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8174 -- Expression (N) to be expanded again.
8178 then
8183 ----------------------------------
8184 -- Resolve_Generalized_Indexing --
8185 ----------------------------------
8193 begin
8194 -- In ASIS mode, propagate the information about the indexes back to
8195 -- to the original indexing node. The generalized indexing is either
8196 -- a function call, or a dereference of one. The actuals include the
8197 -- prefix of the original node, which is the container expression.
8206 loop
8215 -- If expression is to be reanalyzed, reset Generalized_Indexing
8216 -- to recreate call node, as is the case when the expression is
8217 -- part of an expression function.
8226 else
8232 ---------------------------
8233 -- Resolve_If_Expression --
8234 ---------------------------
8243 begin
8248 -- When the "then" expression is of a scalar subtype different from the
8249 -- result subtype, then insert a conversion to ensure the generation of
8250 -- a constraint check. The same is done for the else part below, again
8251 -- comparing subtypes rather than base types.
8255 then
8260 -- If ELSE expression present, just resolve using the determined type
8270 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8271 -- dynamically tagged must be known statically.
8276 then
8282 -- If no ELSE expression is present, root type must be Standard.Boolean
8283 -- and we provide a Standard.True result converted to the appropriate
8284 -- Boolean type (in case it is a derived boolean type).
8287 Else_Expr :=
8292 else
8301 -------------------------------
8302 -- Resolve_Indexed_Component --
8303 -------------------------------
8311 begin
8319 -- Use the context type to select the prefix that yields the correct
8320 -- component type.
8322 declare
8329 begin
8336 and then
8337 Covers
8340 then
8349 else
8355 else
8366 else
8373 -- If prefix is access type, dereference to get real array type.
8374 -- Note: we do not apply an access check because the expander always
8375 -- introduces an explicit dereference, and the check will happen there.
8381 -- If name was overloaded, set component type correctly now
8382 -- If a misplaced call to an entry family (which has no index types)
8383 -- return. Error will be diagnosed from calling context.
8387 else
8394 -- The prefix may have resolved to a string literal, in which case its
8395 -- etype has a special representation. This is only possible currently
8396 -- if the prefix is a static concatenation, written in functional
8397 -- notation.
8402 else
8409 else
8420 -- Do not generate the warning on suspicious index if we are analyzing
8421 -- package Ada.Tags; otherwise we will report the warning with the
8422 -- Prims_Ptr field of the dispatch table.
8425 or else not
8427 Ada_Tags)
8428 then
8433 -- If the array type is atomic, and the component is not atomic, then
8434 -- this is worth a warning, since we have a situation where the access
8435 -- to the component may cause extra read/writes of the atomic array
8436 -- object, or partial word accesses, which could be unexpected.
8442 and then Has_Atomic_Components
8445 then
8446 Error_Msg_N
8448 Error_Msg_N
8453 -----------------------------
8454 -- Resolve_Integer_Literal --
8455 -----------------------------
8458 begin
8463 --------------------------------
8464 -- Resolve_Intrinsic_Operator --
8465 --------------------------------
8474 -- If the operand is a literal, it cannot be the expression in a
8475 -- conversion. Use a qualified expression instead.
8477 ---------------------
8478 -- Convert_Operand --
8479 ---------------------
8485 begin
8487 Res :=
8493 else
8500 -- Start of processing for Resolve_Intrinsic_Operator
8502 begin
8503 -- We must preserve the original entity in a generic setting, so that
8504 -- the legality of the operation can be verified in an instance.
8519 -- If the result or operand types are private, rewrite with unchecked
8520 -- conversions on the operands and the result, to expose the proper
8521 -- underlying numeric type.
8526 then
8531 else
8552 then
8553 -- Add explicit conversion where needed, and save interpretations in
8554 -- case operands are overloaded.
8561 else
8567 else
8577 else
8582 --------------------------------------
8583 -- Resolve_Intrinsic_Unary_Operator --
8584 --------------------------------------
8586 procedure Resolve_Intrinsic_Unary_Operator
8589 is
8594 begin
8613 else
8618 ------------------------
8619 -- Resolve_Logical_Op --
8620 ------------------------
8625 begin
8628 -- Predefined operations on scalar types yield the base type. On the
8629 -- other hand, logical operations on arrays yield the type of the
8630 -- arguments (and the context).
8634 else
8638 -- The following test is required because the operands of the operation
8639 -- may be literals, in which case the resulting type appears to be
8640 -- compatible with a signed integer type, when in fact it is compatible
8641 -- only with modular types. If the context itself is universal, the
8642 -- operation is illegal.
8650 Error_Msg_N
8658 then
8662 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8663 -- is active and the result type is standard Boolean (do not mess with
8664 -- ops that return a nonstandard Boolean type, because something strange
8665 -- is going on).
8667 -- Note: you might expect this replacement to be done during expansion,
8668 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8669 -- is used, no part of the right operand of an "and" or "or" operator
8670 -- should be executed if the left operand would short-circuit the
8671 -- evaluation of the corresponding "and then" or "or else". If we left
8672 -- the replacement to expansion time, then run-time checks associated
8673 -- with such operands would be evaluated unconditionally, due to being
8674 -- before the condition prior to the rewriting as short-circuit forms
8675 -- during expansion.
8677 if Short_Circuit_And_Or
8680 then
8681 -- Mark the corresponding putative SCO operator as truly a logical
8682 -- (and short-circuit) operator.
8695 -- Case of OR changed to OR ELSE
8697 else
8705 -- Return now, since analysis of the rewritten ops will take care of
8706 -- other reference bookkeeping and expression folding.
8721 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8722 -- only when both operands have same static lower and higher bounds. Of
8723 -- course the types have to match, so only check if operands are
8724 -- compatible and the node itself has no errors.
8728 then
8729 declare
8733 begin
8734 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8735 -- operation if not needed.
8742 then
8743 Check_SPARK_05_Restriction
8750 ---------------------------
8751 -- Resolve_Membership_Op --
8752 ---------------------------
8754 -- The context can only be a boolean type, and does not determine the
8755 -- arguments. Arguments should be unambiguous, but the preference rule for
8756 -- universal types applies.
8766 -- Analysis has determined a unique type for the left operand. Use it to
8767 -- resolve the disjuncts.
8769 ----------------------------
8770 -- Resolve_Set_Membership --
8771 ----------------------------
8777 begin
8778 -- If the left operand is overloaded, find type compatible with not
8779 -- overloaded alternative of the right operand.
8788 else
8793 -- Unclear how to resolve expression if all alternatives are also
8794 -- overloaded.
8800 else
8809 -- Alternative is an expression, a range
8810 -- or a subtype mark.
8814 then
8821 -- Check for duplicates for discrete case
8824 declare
8833 begin
8834 -- Loop checking duplicates. This is quadratic, but giant sets
8835 -- are unlikely in this context so it's a reasonable choice.
8842 N_Character_Literal)
8844 then
8862 -- Start of processing for Resolve_Membership_Op
8864 begin
8870 Resolve_Set_Membership;
8874 and then
8876 or else
8879 then
8882 -- Ada 2005 (AI-251): Support the following case:
8884 -- type I is interface;
8885 -- type T is tagged ...
8887 -- function Test (O : I'Class) is
8888 -- begin
8889 -- return O in T'Class.
8890 -- end Test;
8892 -- In this case we have nothing else to do. The membership test will be
8893 -- done at run time.
8900 then
8902 else
8906 -- If mixed-mode operations are present and operands are all literal,
8907 -- the only interpretation involves Duration, which is probably not
8908 -- the intention of the programmer.
8923 then
8929 else
8934 -- Here after resolving membership operation
8941 ------------------
8942 -- Resolve_Null --
8943 ------------------
8948 begin
8949 -- Handle restriction against anonymous null access values This
8950 -- restriction can be turned off using -gnatdj.
8952 -- Ada 2005 (AI-231): Remove restriction
8955 and then not Debug_Flag_J
8958 then
8959 -- In the common case of a call which uses an explicitly null value
8960 -- for an access parameter, give specialized error message.
8963 Error_Msg_N
8966 -- Standard message for all other cases (are there any?)
8968 else
8969 Error_Msg_N
8974 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8975 -- assignment to a null-excluding object
8980 then
8982 Insert_Action
8987 else
8994 -- In a distributed context, null for a remote access to subprogram may
8995 -- need to be replaced with a special record aggregate. In this case,
8996 -- return after having done the transformation.
9001 then
9005 -- The null literal takes its type from the context
9010 -----------------------
9011 -- Resolve_Op_Concat --
9012 -----------------------
9016 -- We wish to avoid deep recursion, because concatenations are often
9017 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9018 -- operands nonrecursively until we find something that is not a simple
9019 -- concatenation (A in this case). We resolve that, and then walk back
9020 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9021 -- to do the rest of the work at each level. The Parent pointers allow
9022 -- us to avoid recursion, and thus avoid running out of memory. See also
9023 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9028 begin
9029 -- The following code is equivalent to:
9031 -- Resolve_Op_Concat_First (NN, Typ);
9032 -- Resolve_Op_Concat_Arg (N, ...);
9033 -- Resolve_Op_Concat_Rest (N, Typ);
9035 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9036 -- operand is a concatenation.
9038 -- Walk down left operands
9040 loop
9049 -- Now (given the above example) NN is A&B and Op1 is A
9051 -- First resolve Op1 ...
9055 -- ... then walk NN back up until we reach N (where we started), calling
9056 -- Resolve_Op_Concat_Rest along the way.
9058 loop
9065 Check_SPARK_05_Restriction
9070 ---------------------------
9071 -- Resolve_Op_Concat_Arg --
9072 ---------------------------
9074 procedure Resolve_Op_Concat_Arg
9079 is
9083 begin
9085 if Is_Comp
9089 then
9091 else
9095 -- If both Array & Array and Array & Component are visible, there is a
9096 -- potential ambiguity that must be reported.
9101 then
9105 -- If the operation is user-defined and not overloaded use its
9106 -- profile. The operation may be a renaming, in which case it has
9107 -- been rewritten, and we want the original profile.
9112 then
9114 Etype
9118 -- Otherwise an aggregate may match both the array type and the
9119 -- component type.
9121 else
9126 else
9130 then
9131 declare
9136 begin
9141 -- Special-case the error message when the overloading is
9142 -- caused by a function that yields an array and can be
9143 -- called without parameters.
9148 Error_Msg_NE
9150 Error_Msg_NE
9154 else
9162 or else
9164 then
9165 Error_Msg_N -- CODEFIX
9183 else
9188 else
9192 -- Concatenation is restricted in SPARK: each operand must be either a
9193 -- string literal, the name of a string constant, a static character or
9194 -- string expression, or another concatenation. Arg cannot be a
9195 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9196 -- separately on each final operand, past concatenation operations.
9200 Check_SPARK_05_Restriction
9208 then
9209 Check_SPARK_05_Restriction
9213 -- Do not issue error on an operand that is neither a character nor a
9214 -- string, as the error is issued in Resolve_Op_Concat.
9216 else
9223 -----------------------------
9224 -- Resolve_Op_Concat_First --
9225 -----------------------------
9232 begin
9233 -- The parser folds an enormous sequence of concatenations of string
9234 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9235 -- in the right operand. If the expression resolves to a predefined "&"
9236 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9237 -- we give an error. See P_Simple_Expression in Par.Ch4.
9242 then
9257 ----------------------------
9258 -- Resolve_Op_Concat_Rest --
9259 ----------------------------
9265 begin
9274 -- If this is not a static concatenation, but the result is a string
9275 -- type (and not an array of strings) ensure that static string operands
9276 -- have their subtypes properly constructed.
9280 then
9286 ----------------------
9287 -- Resolve_Op_Expon --
9288 ----------------------
9293 begin
9294 -- Catch attempts to do fixed-point exponentiation with universal
9295 -- operands, which is a case where the illegality is not caught during
9296 -- normal operator analysis. This is not done in preanalysis mode
9297 -- since the tree is not fully decorated during preanalysis.
9308 then
9318 then
9325 then
9329 -- We do the resolution using the base type, because intermediate values
9330 -- in expressions are always of the base type, not a subtype of it.
9335 -- For integer types, right argument must be in Natural range
9350 -- Evaluate the exponentiation operator for dimensioned type
9353 else
9357 -- Set overflow checking bit. Much cleverer code needed here eventually
9358 -- and perhaps the Resolve routines should be separated for the various
9359 -- arithmetic operations, since they will need different processing. ???
9368 --------------------
9369 -- Resolve_Op_Not --
9370 --------------------
9376 -- This function determines if the parent node is a boolean operator or
9377 -- operation (comparison op, membership test, or short circuit form) and
9378 -- the not in question is the left operand of this operation. Note that
9379 -- if the not is in parens, then false is returned.
9381 -----------------------
9382 -- Parent_Is_Boolean --
9383 -----------------------
9386 begin
9390 else
9392 when N_Op_And |
9393 N_Op_Eq |
9394 N_Op_Ge |
9395 N_Op_Gt |
9396 N_Op_Le |
9397 N_Op_Lt |
9398 N_Op_Ne |
9399 N_Op_Or |
9400 N_Op_Xor |
9401 N_In |
9402 N_Not_In |
9403 N_And_Then |
9404 N_Or_Else =>
9414 -- Start of processing for Resolve_Op_Not
9416 begin
9417 -- Predefined operations on scalar types yield the base type. On the
9418 -- other hand, logical operations on arrays yield the type of the
9419 -- arguments (and the context).
9423 else
9427 -- Straightforward case of incorrect arguments
9434 -- Special case of probable missing parens
9438 Error_Msg_N
9441 else
9442 Error_Msg_N
9449 -- OK resolution of NOT
9451 else
9452 -- Warn if non-boolean types involved. This is a case like not a < b
9453 -- where a and b are modular, where we will get (not a) < b and most
9454 -- likely not (a < b) was intended.
9456 if Warn_On_Questionable_Missing_Parens
9458 and then Parent_Is_Boolean
9459 then
9463 -- Warn on double negation if checking redundant constructs
9465 if Warn_On_Redundant_Constructs
9470 then
9474 -- Complete resolution and evaluation of NOT
9484 -----------------------------
9485 -- Resolve_Operator_Symbol --
9486 -----------------------------
9488 -- Nothing to be done, all resolved already
9494 begin
9498 ----------------------------------
9499 -- Resolve_Qualified_Expression --
9500 ----------------------------------
9508 begin
9511 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9512 -- operation if not needed.
9519 then
9520 Check_SPARK_05_Restriction
9524 -- A qualified expression requires an exact match of the type, class-
9525 -- wide matching is not allowed. However, if the qualifying type is
9526 -- specific and the expression has a class-wide type, it may still be
9527 -- okay, since it can be the result of the expansion of a call to a
9528 -- dispatching function, so we also have to check class-wideness of the
9529 -- type of the expression's original node.
9532 or else
9536 then
9540 -- If the target type is unconstrained, then we reset the type of the
9541 -- result from the type of the expression. For other cases, the actual
9542 -- subtype of the expression is the target type.
9546 then
9553 -- If we still have a qualified expression after the static evaluation,
9554 -- then apply a scalar range check if needed. The reason that we do this
9555 -- after the Eval call is that otherwise, the application of the range
9556 -- check may convert an illegal static expression and result in warning
9557 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9564 ------------------------------
9565 -- Resolve_Raise_Expression --
9566 ------------------------------
9569 begin
9573 else
9578 -------------------
9579 -- Resolve_Range --
9580 -------------------
9587 -- Returns True if N is of the form X'First .. X'Last where X is the
9588 -- same entity for both attributes.
9590 --------------------
9591 -- First_Last_Ref --
9592 --------------------
9598 begin
9603 then
9604 declare
9607 begin
9611 then
9620 -- Start of processing for Resolve_Range
9622 begin
9627 -- Check for inappropriate range on unordered enumeration type
9631 -- Exclude X'First .. X'Last if X is the same entity for both
9633 and then not First_Last_Ref
9634 then
9636 Error_Msg_NE
9643 -- We have to check the bounds for being within the base range as
9644 -- required for a non-static context. Normally this is automatic and
9645 -- done as part of evaluating expressions, but the N_Range node is an
9646 -- exception, since in GNAT we consider this node to be a subexpression,
9647 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9648 -- this, but that would put the test on the main evaluation path for
9649 -- expressions.
9654 -- Check for an ambiguous range over character literals. This will
9655 -- happen with a membership test involving only literals.
9663 -- If bounds are static, constant-fold them, so size computations are
9664 -- identical between front-end and back-end. Do not perform this
9665 -- transformation while analyzing generic units, as type information
9666 -- would be lost when reanalyzing the constant node in the instance.
9679 --------------------------
9680 -- Resolve_Real_Literal --
9681 --------------------------
9686 begin
9687 -- Special processing for fixed-point literals to make sure that the
9688 -- value is an exact multiple of small where this is required. We skip
9689 -- this for the universal real case, and also for generic types.
9695 then
9696 declare
9703 begin
9704 -- Case of literal is not an exact multiple of the Small
9708 -- For a source program literal for a decimal fixed-point type,
9709 -- this is statically illegal (RM 4.9(36)).
9714 then
9718 -- Generate a warning if literal from source
9721 and then Warn_On_Bad_Fixed_Value
9722 then
9723 Error_Msg_N
9725 N);
9728 -- Replace literal by a value that is the exact representation
9729 -- of a value of the type, i.e. a multiple of the small value,
9730 -- by truncation, since Machine_Rounds is false for all GNAT
9731 -- fixed-point types (RM 4.9(38)).
9741 -- In all cases, set the corresponding integer field
9747 -- Now replace the actual type by the expected type as usual
9753 -----------------------
9754 -- Resolve_Reference --
9755 -----------------------
9760 begin
9761 -- Replace general access with specific type
9769 -- If we are taking the reference of a volatile entity, then treat it as
9770 -- a potential modification of this entity. This is too conservative,
9771 -- but necessary because remove side effects can cause transformations
9772 -- of normal assignments into reference sequences that otherwise fail to
9773 -- notice the modification.
9780 --------------------------------
9781 -- Resolve_Selected_Component --
9782 --------------------------------
9797 -- Check whether this is the initialization of a component within an
9798 -- init proc (by assignment or call to another init proc). If true,
9799 -- there is no need for a discriminant check.
9801 --------------------
9802 -- Init_Component --
9803 --------------------
9806 begin
9807 return Inside_Init_Proc
9813 -- Start of processing for Resolve_Selected_Component
9815 begin
9818 -- Use the context type to select the prefix that has a selector
9819 -- of the correct name and type.
9827 else
9831 -- Locate selected component. For a private prefix the selector
9832 -- can denote a discriminant.
9836 -- The visible components of a class-wide type are those of
9837 -- the root type.
9847 then
9854 else
9858 Error_Msg_N
9863 else
9866 -- There may be an implicit dereference. Retrieve
9867 -- designated record type.
9871 else
9877 -- Resolution chooses the new interpretation.
9878 -- Find the component with the right name.
9883 loop
9900 -- There must be a legal interpretation at this point
9907 else
9908 -- Resolve prefix with its type
9913 -- Generate cross-reference. We needed to wait until full overloading
9914 -- resolution was complete to do this, since otherwise we can't tell if
9915 -- we are an lvalue or not.
9919 else
9923 -- If prefix is an access type, the node will be transformed into an
9924 -- explicit dereference during expansion. The type of the node is the
9925 -- designated type of that of the prefix.
9930 else
9934 -- Set flag for expander if discriminant check required on a component
9935 -- appearing within a variant.
9941 and then
9944 and then not Init_Component
9945 then
9953 -- If the prefix is a record conversion, this may be a renamed
9954 -- discriminant whose bounds differ from those of the original
9955 -- one, so we must ensure that a range check is performed.
9960 then
9964 -- Note: No Eval processing is required, because the prefix is of a
9965 -- record type, or protected type, and neither can possibly be static.
9967 -- If the record type is atomic, and the component is non-atomic, then
9968 -- this is worth a warning, since we have a situation where the access
9969 -- to the component may cause extra read/writes of the atomic array
9970 -- object, or partial word accesses, both of which may be unexpected.
9976 then
9977 Error_Msg_N
9980 Error_Msg_N
9988 -------------------
9989 -- Resolve_Shift --
9990 -------------------
9997 begin
9998 -- We do the resolution using the base type, because intermediate values
9999 -- in expressions always are of the base type, not a subtype of it.
10012 ---------------------------
10013 -- Resolve_Short_Circuit --
10014 ---------------------------
10021 begin
10022 -- Ensure all actions associated with the left operand (e.g.
10023 -- finalization of transient controlled objects) are fully evaluated
10024 -- locally within an expression with actions. This is particularly
10025 -- helpful for coverage analysis. However this should not happen in
10026 -- generics.
10029 declare
10031 begin
10039 -- Set Comes_From_Source on L to preserve warnings for unset
10040 -- reference.
10049 -- Check for issuing warning for always False assert/check, this happens
10050 -- when assertions are turned off, in which case the pragma Assert/Check
10051 -- was transformed into:
10053 -- if False and then <condition> then ...
10055 -- and we detect this pattern
10057 if Warn_On_Assertion_Failure
10064 then
10065 declare
10068 begin
10069 -- Special handling of Asssert pragma
10073 then
10074 declare
10076 Original_Node
10077 (Expression
10080 begin
10081 -- Don't warn if original condition is explicit False,
10082 -- since obviously the failure is expected in this case.
10086 then
10089 -- Issue warning. We do not want the deletion of the
10090 -- IF/AND-THEN to take this message with it. We achieve this
10091 -- by making sure that the expanded code points to the Sloc
10092 -- of the expression, not the original pragma.
10094 else
10095 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10096 -- The source location of the expression is not usually
10097 -- the best choice here. For example, it gets located on
10098 -- the last AND keyword in a chain of boolean expressiond
10099 -- AND'ed together. It is best to put the message on the
10100 -- first character of the assertion, which is the effect
10101 -- of the First_Node call here.
10103 Error_Msg_F
10105 Expression
10110 -- Similar processing for Check pragma
10114 then
10115 -- Don't want to warn if original condition is explicit False
10117 declare
10119 Original_Node
10120 (Expression
10122 begin
10125 then
10128 -- Post warning
10130 else
10131 -- Again use Error_Msg_F rather than Error_Msg_N, see
10132 -- comment above for an explanation of why we do this.
10134 Error_Msg_F
10136 Expression
10144 -- Continue with processing of short circuit
10153 -------------------
10154 -- Resolve_Slice --
10155 -------------------
10164 begin
10167 -- Use the context type to select the prefix that yields the correct
10168 -- array type.
10170 declare
10177 begin
10185 then
10193 else
10198 else
10209 else
10219 -- If the prefix is an access to an unconstrained array, we must use
10220 -- the actual subtype of the object to perform the index checks. The
10221 -- object denoted by the prefix is implicit in the node, so we build
10222 -- an explicit representation for it in order to compute the actual
10223 -- subtype.
10228 declare
10232 begin
10243 then
10246 -- If the name is a selected component that depends on discriminants,
10247 -- build an actual subtype for it. This can happen only when the name
10248 -- itself is overloaded; otherwise the actual subtype is created when
10249 -- the selected component is analyzed.
10252 and then Full_Analysis
10254 then
10255 declare
10258 begin
10263 -- Maybe this should just be "else", instead of checking for the
10264 -- specific case of slice??? This is needed for the case where the
10265 -- prefix is an Image attribute, which gets expanded to a slice, and so
10266 -- has a constrained subtype which we want to use for the slice range
10267 -- check applied below (the range check won't get done if the
10268 -- unconstrained subtype of the 'Image is used).
10274 -- Obtain the type of the array index
10278 else
10282 -- If name was overloaded, set slice type correctly now
10286 -- Handle the generation of a range check that compares the array index
10287 -- against the discrete_range. The check is not applied to internally
10288 -- built nodes associated with the expansion of dispatch tables. Check
10289 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10290 -- the unit.
10292 if Tagged_Type_Expansion
10298 then
10301 -- The discrete_range is specified by a subtype indication. Create a
10302 -- shallow copy and inherit the type, parent and source location from
10303 -- the discrete_range. This ensures that the range check is inserted
10304 -- relative to the slice and that the runtime exception points to the
10305 -- proper construct.
10314 -- The discrete_range is a regular range. Resolve the bounds and remove
10315 -- their side effects.
10317 else
10334 -- Check bad use of type with predicates
10336 declare
10339 begin
10342 then
10344 else
10349 Bad_Predicated_Subtype_Use
10354 -- Otherwise here is where we check suspicious indexes
10365 ----------------------------
10366 -- Resolve_String_Literal --
10367 ----------------------------
10378 begin
10379 -- For a string appearing in a concatenation, defer creation of the
10380 -- string_literal_subtype until the end of the resolution of the
10381 -- concatenation, because the literal may be constant-folded away. This
10382 -- is a useful optimization for long concatenation expressions.
10384 -- If the string is an aggregate built for a single character (which
10385 -- happens in a non-static context) or a is null string to which special
10386 -- checks may apply, we build the subtype. Wide strings must also get a
10387 -- string subtype if they come from a one character aggregate. Strings
10388 -- generated by attributes might be static, but it is often hard to
10389 -- determine whether the enclosing context is static, so we generate
10390 -- subtypes for them as well, thus losing some rarer optimizations ???
10391 -- Same for strings that come from a static conversion.
10393 Need_Check :=
10402 -- If the resolving type is itself a string literal subtype, we can just
10403 -- reuse it, since there is no point in creating another.
10409 and then not Need_Check
10411 N_Attribute_Reference,
10412 N_Qualified_Expression,
10413 N_Type_Conversion)
10414 then
10417 -- Do not generate a string literal subtype for the default expression
10418 -- of a formal parameter in GNATprove mode. This is because the string
10419 -- subtype is associated with the freezing actions of the subprogram,
10420 -- however freezing is disabled in GNATprove mode and as a result the
10421 -- subtype is unavailable.
10423 elsif GNATprove_Mode
10425 then
10428 -- Otherwise we must create a string literal subtype. Note that the
10429 -- whole idea of string literal subtypes is simply to avoid the need
10430 -- for building a full fledged array subtype for each literal.
10432 else
10438 or else Need_Check
10439 then
10446 then
10452 -- The validity of a null string has been checked in the call to
10453 -- Eval_String_Literal.
10458 -- Always accept string literal with component type Any_Character, which
10459 -- occurs in error situations and in comparisons of literals, both of
10460 -- which should accept all literals.
10465 -- If the type is bit-packed, then we always transform the string
10466 -- literal into a full fledged aggregate.
10471 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10473 else
10474 -- For Standard.Wide_Wide_String, or any other type whose component
10475 -- type is Standard.Wide_Wide_Character, we know that all the
10476 -- characters in the string must be acceptable, since the parser
10477 -- accepted the characters as valid character literals.
10482 -- For the case of Standard.String, or any other type whose component
10483 -- type is Standard.Character, we must make sure that there are no
10484 -- wide characters in the string, i.e. that it is entirely composed
10485 -- of characters in range of type Character.
10487 -- If the string literal is the result of a static concatenation, the
10488 -- test has already been performed on the components, and need not be
10489 -- repeated.
10493 then
10497 -- If we are out of range, post error. This is one of the
10498 -- very few places that we place the flag in the middle of
10499 -- a token, right under the offending wide character. Not
10500 -- quite clear if this is right wrt wide character encoding
10501 -- sequences, but it's only an error message.
10503 Error_Msg
10510 -- For the case of Standard.Wide_String, or any other type whose
10511 -- component type is Standard.Wide_Character, we must make sure that
10512 -- there are no wide characters in the string, i.e. that it is
10513 -- entirely composed of characters in range of type Wide_Character.
10515 -- If the string literal is the result of a static concatenation,
10516 -- the test has already been performed on the components, and need
10517 -- not be repeated.
10521 then
10525 -- If we are out of range, post error. This is one of the
10526 -- very few places that we place the flag in the middle of
10527 -- a token, right under the offending wide character.
10529 -- This is not quite right, because characters in general
10530 -- will take more than one character position ???
10532 Error_Msg
10539 -- If the root type is not a standard character, then we will convert
10540 -- the string into an aggregate and will let the aggregate code do
10541 -- the checking. Standard Wide_Wide_Character is also OK here.
10543 else
10547 -- See if the component type of the array corresponding to the string
10548 -- has compile time known bounds. If yes we can directly check
10549 -- whether the evaluation of the string will raise constraint error.
10550 -- Otherwise we need to transform the string literal into the
10551 -- corresponding character aggregate and let the aggregate code do
10552 -- the checking.
10556 -- Check for the case of full range, where we are definitely OK
10562 -- Here the range is not the complete base type range, so check
10564 declare
10572 begin
10575 then
10581 then
10582 Apply_Compile_Time_Constraint_Error
10584 CE_Range_Check_Failed,
10595 -- If we got here we meed to transform the string literal into the
10596 -- equivalent qualified positional array aggregate. This is rather
10597 -- heavy artillery for this situation, but it is hard work to avoid.
10599 declare
10604 begin
10605 -- Build the character literals, we give them source locations that
10606 -- correspond to the string positions, which is a bit tricky given
10607 -- the possible presence of wide character escape sequences.
10621 -- Should we have a call to Skip_Wide here ???
10623 -- ??? else
10624 -- Skip_Wide (P);
10632 Expression =>
10639 -----------------------------
10640 -- Resolve_Type_Conversion --
10641 -----------------------------
10653 -- Set to False to suppress cases where we want to suppress the test
10654 -- for redundancy to avoid possible false positives on this warning.
10656 begin
10657 if not Conv_OK
10659 then
10663 -- If the Operand Etype is Universal_Fixed, then the conversion is
10664 -- never redundant. We need this check because by the time we have
10665 -- finished the rather complex transformation, the conversion looks
10666 -- redundant when it is not.
10671 -- If the operand is marked as Any_Fixed, then special processing is
10672 -- required. This is also a case where we suppress the test for a
10673 -- redundant conversion, since most certainly it is not redundant.
10678 -- Mixed-mode operation involving a literal. Context must be a fixed
10679 -- type which is applied to the literal subsequently.
10687 or else
10689 then
10690 -- Return if expression is ambiguous
10695 -- If nothing else, the available fixed type is Duration
10697 else
10701 -- Resolve the real operand with largest available precision
10705 else
10711 -- If the operand is a literal (it could be a non-static and
10712 -- illegal exponentiation) check whether the use of Duration
10713 -- is potentially inaccurate.
10718 then
10719 Error_Msg_N
10722 Error_Msg_N
10729 then
10732 else
10741 -- In SPARK, a type conversion between array types should be restricted
10742 -- to types which have matching static bounds.
10744 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10745 -- operation if not needed.
10752 then
10753 Check_SPARK_05_Restriction
10757 -- In formal mode, the operand of an ancestor type conversion must be an
10758 -- object (not an expression).
10766 then
10772 -- Note: we do the Eval_Type_Conversion call before applying the
10773 -- required checks for a subtype conversion. This is important, since
10774 -- both are prepared under certain circumstances to change the type
10775 -- conversion to a constraint error node, but in the case of
10776 -- Eval_Type_Conversion this may reflect an illegality in the static
10777 -- case, and we would miss the illegality (getting only a warning
10778 -- message), if we applied the type conversion checks first.
10782 -- Even when evaluation is not possible, we may be able to simplify the
10783 -- conversion or its expression. This needs to be done before applying
10784 -- checks, since otherwise the checks may use the original expression
10785 -- and defeat the simplifications. This is specifically the case for
10786 -- elimination of the floating-point Truncation attribute in
10787 -- float-to-int conversions.
10791 -- If after evaluation we still have a type conversion, then we may need
10792 -- to apply checks required for a subtype conversion.
10794 -- Skip these type conversion checks if universal fixed operands
10795 -- operands involved, since range checks are handled separately for
10796 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10802 then
10806 -- Issue warning for conversion of simple object to its own type. We
10807 -- have to test the original nodes, since they may have been rewritten
10808 -- by various optimizations.
10812 -- Here we test for a redundant conversion if the warning mode is
10813 -- active (and was not locally reset), and we have a type conversion
10814 -- from source not appearing in a generic instance.
10816 if Test_Redundant
10819 and then not In_Instance
10820 then
10824 -- If the node is part of a larger expression, the Target_Type
10825 -- may not be the original type of the node if the context is a
10826 -- condition. Recover original type to see if conversion is needed.
10830 then
10834 -- If we have an entity name, then give the warning if the entity
10835 -- is the right type, or if it is a loop parameter covered by the
10836 -- original type (that's needed because loop parameters have an
10837 -- odd subtype coming from the bounds).
10840 and then
10842 or else
10846 -- If not an entity, then type of expression must match
10849 then
10850 -- One more check, do not give warning if the analyzed conversion
10851 -- has an expression with non-static bounds, and the bounds of the
10852 -- target are static. This avoids junk warnings in cases where the
10853 -- conversion is necessary to establish staticness, for example in
10854 -- a case statement.
10858 then
10861 -- Finally, if this type conversion occurs in a context requiring
10862 -- a prefix, and the expression is a qualified expression then the
10863 -- type conversion is not redundant, since a qualified expression
10864 -- is not a prefix, whereas a type conversion is. For example, "X
10865 -- := T'(Funx(...)).Y;" is illegal because a selected component
10866 -- requires a prefix, but a type conversion makes it legal: "X :=
10867 -- T(T'(Funx(...))).Y;"
10869 -- In Ada 2012, a qualified expression is a name, so this idiom is
10870 -- no longer needed, but we still suppress the warning because it
10871 -- seems unfriendly for warnings to pop up when you switch to the
10872 -- newer language version.
10876 N_Indexed_Component,
10877 N_Selected_Component,
10878 N_Slice,
10879 N_Explicit_Dereference)
10880 then
10883 -- Never warn on conversion to Long_Long_Integer'Base since
10884 -- that is most likely an artifact of the extended overflow
10885 -- checking and comes from complex expanded code.
10890 -- Here we give the redundant conversion warning. If it is an
10891 -- entity, give the name of the entity in the message. If not,
10892 -- just mention the expression.
10894 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10896 else
10899 Error_Msg_NE -- CODEFIX
10902 else
10903 Error_Msg_NE
10911 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10912 -- No need to perform any interface conversion if the type of the
10913 -- expression coincides with the target type.
10916 and then Expander_Active
10918 then
10919 declare
10923 begin
10924 -- If the type of the operand is a limited view, use nonlimited
10925 -- view when available. If it is a class-wide type, recover the
10926 -- class-wide type of the nonlimited view.
10930 then
10946 -- Conversion from interface type
10950 -- Ada 2005 (AI-217): Handle entities from limited views
10954 Error_Msg_NE -- CODEFIX
10957 Error_Msg_N
10959 N);
10962 and then not
10965 then
10967 Error_Msg_NE -- CODEFIX
10970 Error_Msg_N
10972 N);
10974 else
10978 -- Conversion to interface type
10982 -- Handle subtypes
10989 or else Interface_Present_In_Ancestor
10992 then
10994 else
10997 Error_Msg_N
11005 -- Ada 2012: if target type has predicates, the result requires a
11006 -- predicate check. If the context is a call to another predicate
11007 -- check we must prevent infinite recursion.
11013 or else
11015 then
11018 else
11023 -- If at this stage we have a real to integer conversion, make sure
11024 -- that the Do_Range_Check flag is set, because such conversions in
11025 -- general need a range check. We only need this if expansion is off
11026 -- or we are in GNATProve mode.
11032 then
11037 ----------------------
11038 -- Resolve_Unary_Op --
11039 ----------------------
11048 begin
11051 Check_SPARK_05_Restriction
11055 -- Deal with intrinsic unary operators
11061 then
11066 -- Deal with universal cases
11069 or else
11071 then
11078 -- Generate warning for expressions like abs (x mod 2)
11080 if Warn_On_Redundant_Constructs
11082 then
11086 Error_Msg_N -- CODEFIX
11091 -- Deal with reference generation
11098 -- Set overflow checking bit. Much cleverer code needed here eventually
11099 -- and perhaps the Resolve routines should be separated for the various
11100 -- arithmetic operations, since they will need different processing ???
11108 -- Generate warning for expressions like -5 mod 3 for integers. No need
11109 -- to worry in the floating-point case, since parens do not affect the
11110 -- result so there is no point in giving in a warning.
11112 declare
11121 begin
11122 if Warn_On_Questionable_Missing_Parens
11126 then
11129 -- We are looking for cases where the right operand is not
11130 -- parenthesized, and is a binary operator, multiply, divide, or
11131 -- mod. These are the cases where the grouping can affect results.
11135 then
11136 -- For mod, we always give the warning, since the value is
11137 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11138 -- -(5 mod 315)). But for the other cases, the only concern is
11139 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11140 -- overflows, but (-2) * 64 does not). So we try to give the
11141 -- message only when overflow is possible.
11145 then
11150 else
11156 else
11160 -- Note that the test below is deliberately excluding the
11161 -- largest negative number, since that is a potentially
11162 -- troublesome case (e.g. -2 * x, where the result is the
11163 -- largest negative integer has an overflow with 2 * x).
11170 -- For the multiplication case, the only case we have to worry
11171 -- about is when (-a)*b is exactly the largest negative number
11172 -- so that -(a*b) can cause overflow. This can only happen if
11173 -- a is a power of 2, and more generally if any operand is a
11174 -- constant that is not a power of 2, then the parentheses
11175 -- cannot affect whether overflow occurs. We only bother to
11176 -- test the left most operand
11178 -- Loop looking at left operands for one that has known value
11185 -- Operand value of 0 or 1 skips warning
11190 -- Otherwise check power of 2, if power of 2, warn, if
11191 -- anything else, skip warning.
11193 else
11197 else
11206 -- Keep looking at left operands
11211 -- For rem or "/" we can only have a problematic situation
11212 -- if the divisor has a value of minus one or one. Otherwise
11213 -- overflow is impossible (divisor > 1) or we have a case of
11214 -- division by zero in any case.
11219 then
11223 -- If we fall through warning should be issued
11225 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11227 Error_Msg_N
11234 ----------------------------------
11235 -- Resolve_Unchecked_Expression --
11236 ----------------------------------
11238 procedure Resolve_Unchecked_Expression
11241 is
11242 begin
11247 ---------------------------------------
11248 -- Resolve_Unchecked_Type_Conversion --
11249 ---------------------------------------
11251 procedure Resolve_Unchecked_Type_Conversion
11254 is
11260 begin
11261 -- Resolve operand using its own type
11265 -- In an inlined context, the unchecked conversion may be applied
11266 -- to a literal, in which case its type is the type of the context.
11267 -- (In other contexts conversions cannot apply to literals).
11269 if In_Inlined_Body
11273 then
11281 ------------------------------
11282 -- Rewrite_Operator_As_Call --
11283 ------------------------------
11290 begin
11297 New_N :=
11308 ------------------------------
11309 -- Rewrite_Renamed_Operator --
11310 ------------------------------
11312 procedure Rewrite_Renamed_Operator
11316 is
11321 begin
11322 -- Do not perform this transformation within a pre/postcondition,
11323 -- because the expression will be re-analyzed, and the transformation
11324 -- might affect the visibility of the operator, e.g. in an instance.
11330 -- Rewrite the operator node using the real operator, not its renaming.
11331 -- Exclude user-defined intrinsic operations of the same name, which are
11332 -- treated separately and rewritten as calls.
11341 -- Indicate that both the original entity and its renaming are
11342 -- referenced at this point.
11353 -- If the context type is private, add the appropriate conversions so
11354 -- that the operator is applied to the full view. This is done in the
11355 -- routines that resolve intrinsic operators.
11359 then
11361 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
11362 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
11375 -- Operator renames a user-defined operator of the same name. Use the
11376 -- original operator in the node, which is the one Gigi knows about.
11383 -----------------------
11384 -- Set_Slice_Subtype --
11385 -----------------------
11387 -- Build an implicit subtype declaration to represent the type delivered by
11388 -- the slice. This is an abbreviated version of an array subtype. We define
11389 -- an index subtype for the slice, using either the subtype name or the
11390 -- discrete range of the slice. To be consistent with index usage elsewhere
11391 -- we create a list header to hold the single index. This list is not
11392 -- otherwise attached to the syntax tree.
11403 begin
11409 else
11410 -- We force the evaluation of a range. This is definitely needed in
11411 -- the renamed case, and seems safer to do unconditionally. Note in
11412 -- any case that since we will create and insert an Itype referring
11413 -- to this range, we must make sure any side effect removal actions
11414 -- are inserted before the Itype definition.
11420 -- If the discrete range is given by a subtype indication, the
11421 -- type of the slice is the base of the subtype mark.
11424 declare
11426 begin
11435 -- Take a new copy of Drange (where bounds have been rewritten to
11436 -- reference side-effect-free names). Using a separate tree ensures
11437 -- that further expansion (e.g. while rewriting a slice assignment
11438 -- into a FOR loop) does not attempt to remove side effects on the
11439 -- bounds again (which would cause the bounds in the index subtype
11440 -- definition to refer to temporaries before they are defined) (the
11441 -- reason is that some names are considered side effect free here
11442 -- for the subtype, but not in the context of a loop iteration
11443 -- scheme).
11464 -- The Etype of the existing Slice node is reset to this slice subtype.
11465 -- Its bounds are obtained from its first index.
11469 -- For packed slice subtypes, freeze immediately (except in the case of
11470 -- being in a "spec expression" where we never freeze when we first see
11471 -- the expression).
11476 -- For all other cases insert an itype reference in the slice's actions
11477 -- so that the itype is frozen at the proper place in the tree (i.e. at
11478 -- the point where actions for the slice are analyzed). Note that this
11479 -- is different from freezing the itype immediately, which might be
11480 -- premature (e.g. if the slice is within a transient scope). This needs
11481 -- to be done only if expansion is enabled.
11488 --------------------------------
11489 -- Set_String_Literal_Subtype --
11490 --------------------------------
11498 begin
11510 -- The low bound is set from the low bound of the corresponding index
11511 -- type. Note that we do not store the high bound in the string literal
11512 -- subtype, but it can be deduced if necessary from the length and the
11513 -- low bound.
11518 -- If the lower bound is not static we create a range for the string
11519 -- literal, using the index type and the known length of the literal.
11520 -- The index type is not necessarily Positive, so the upper bound is
11521 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11523 else
11524 declare
11530 Prefix =>
11534 Left_Opnd =>
11537 Prefix =>
11539 Expressions =>
11541 Right_Opnd =>
11550 begin
11552 Set_String_Literal_Low_Bound
11555 else
11556 -- If the index type is an enumeration type, build bounds
11557 -- expression with attributes.
11559 Set_String_Literal_Low_Bound
11563 Prefix =>
11570 -- Build bona fide subtype for the string, and wrap it in an
11571 -- unchecked conversion, because the backend expects the
11572 -- String_Literal_Subtype to have a static lower bound.
11574 Index_Subtype :=
11581 -- In the context, the Index_Type may already have a constraint,
11582 -- so use common base type on string subtype. The base type may
11583 -- be used when generating attributes of the string, for example
11584 -- in the context of a slice assignment.
11609 ------------------------------
11610 -- Simplify_Type_Conversion --
11611 ------------------------------
11614 begin
11616 declare
11621 begin
11622 -- Special processing if the conversion is the expression of a
11623 -- Rounding or Truncation attribute reference. In this case we
11624 -- replace:
11626 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11628 -- by
11630 -- ityp (x)
11632 -- with the Float_Truncate flag set to False or True respectively,
11633 -- which is more efficient.
11636 and then
11642 Name_Truncation)
11643 then
11644 declare
11647 begin
11657 -----------------------------
11658 -- Unique_Fixed_Point_Type --
11659 -----------------------------
11668 -- Give error messages for true ambiguity. Messages are posted on node
11669 -- N, and entities T1, T2 are the possible interpretations.
11671 -----------------------
11672 -- Fixed_Point_Error --
11673 -----------------------
11676 begin
11682 -- Start of processing for Unique_Fixed_Point_Type
11684 begin
11685 -- The operations on Duration are visible, so Duration is always a
11686 -- possible interpretation.
11690 -- Look for fixed-point types in enclosing scopes
11699 then
11701 Fixed_Point_Error;
11703 else
11714 -- Look for visible fixed type declarations in the context
11725 then
11727 Fixed_Point_Error;
11729 else
11742 Error_Msg_NE
11744 else
11745 Error_Msg_NE
11752 ----------------------
11753 -- Valid_Conversion --
11754 ----------------------
11756 function Valid_Conversion
11761 is
11766 function Conversion_Check
11769 -- Little routine to post Msg if Valid is False, returns Valid value
11772 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11774 procedure Conversion_Error_NE
11778 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11780 function Valid_Tagged_Conversion
11783 -- Specifically test for validity of tagged conversions
11786 -- Check index and component conformance, and accessibility levels if
11787 -- the component types are anonymous access types (Ada 2005).
11789 ----------------------
11790 -- Conversion_Check --
11791 ----------------------
11793 function Conversion_Check
11796 is
11797 begin
11798 if not Valid
11800 -- A generic unit has already been analyzed and we have verified
11801 -- that a particular conversion is OK in that context. Since the
11802 -- instance is reanalyzed without relying on the relationships
11803 -- established during the analysis of the generic, it is possible
11804 -- to end up with inconsistent views of private types. Do not emit
11805 -- the error message in such cases. The rest of the machinery in
11806 -- Valid_Conversion still ensures the proper compatibility of
11807 -- target and operand types.
11809 and then not In_Instance
11810 then
11817 ------------------------
11818 -- Conversion_Error_N --
11819 ------------------------
11822 begin
11828 -------------------------
11829 -- Conversion_Error_NE --
11830 -------------------------
11832 procedure Conversion_Error_NE
11836 is
11837 begin
11843 ----------------------------
11844 -- Valid_Array_Conversion --
11845 ----------------------------
11848 is
11863 begin
11864 -- Error if wrong number of dimensions
11866 if
11868 then
11869 Conversion_Error_N
11873 -- Number of dimensions matches
11875 else
11876 -- Loop through indexes of the two arrays
11884 -- Error if index types are incompatible
11890 then
11891 Conversion_Error_N
11893 Operand);
11901 -- If component types have same base type, all set
11906 -- Here if base types of components are not the same. The only
11907 -- time this is allowed is if we have anonymous access types.
11909 -- The conversion of arrays of anonymous access types can lead
11910 -- to dangling pointers. AI-392 formalizes the accessibility
11911 -- checks that must be applied to such conversions to prevent
11912 -- out-of-scope references.
11914 elsif Ekind_In
11916 E_Anonymous_Access_Subprogram_Type)
11918 and then
11920 then
11923 then
11926 Conversion_Error_N
11936 -- Conversion not allowed because of accessibility levels
11938 else
11939 Conversion_Error_N
11945 else
11949 -- All other cases where component base types do not match
11951 else
11952 Conversion_Error_N
11954 Operand);
11958 -- Check that component subtypes statically match. For numeric
11959 -- types this means that both must be either constrained or
11960 -- unconstrained. For enumeration types the bounds must match.
11961 -- All of this is checked in Subtypes_Statically_Match.
11963 if not Subtypes_Statically_Match
11965 then
11966 Conversion_Error_N
11975 -----------------------------
11976 -- Valid_Tagged_Conversion --
11977 -----------------------------
11979 function Valid_Tagged_Conversion
11982 is
11983 begin
11984 -- Upward conversions are allowed (RM 4.6(22))
11988 then
11991 -- Downward conversion are allowed if the operand is class-wide
11992 -- (RM 4.6(23)).
11996 then
12001 then
12002 return
12006 -- Ada 2005 (AI-251): The conversion to/from interface types is
12007 -- always valid
12012 -- If the operand is a class-wide type obtained through a limited_
12013 -- with clause, and the context includes the nonlimited view, use
12014 -- it to determine whether the conversion is legal.
12020 then
12025 then
12028 else
12029 Conversion_Error_NE
12036 -- Start of processing for Valid_Conversion
12038 begin
12042 declare
12050 begin
12051 -- Remove procedure calls, which syntactically cannot appear in
12052 -- this context, but which cannot be removed by type checking,
12053 -- because the context does not impose a type.
12055 -- The node may be labelled overloaded, but still contain only one
12056 -- interpretation because others were discarded earlier. If this
12057 -- is the case, retain the single interpretation if legal.
12065 then
12066 -- More than one candidate interpretation is available
12074 -- When compiling for a system where Address is of a visible
12075 -- integer type, spurious ambiguities can be produced when
12076 -- arithmetic operations have a literal operand and return
12077 -- System.Address or a descendant of it. These ambiguities
12078 -- are usually resolved by the context, but for conversions
12079 -- there is no context type and the removal of the spurious
12080 -- operations must be done explicitly here.
12082 if not Address_Is_Private
12084 then
12109 Conversion_Error_N
12112 -- If the interpretation involves a standard operator, use
12113 -- the location of the type, which may be user-defined.
12117 else
12121 Conversion_Error_N -- CODEFIX
12126 else
12130 Conversion_Error_N -- CODEFIX
12142 -- Deal with conversion of integer type to address if the pragma
12143 -- Allow_Integer_Address is in effect. We convert the conversion to
12144 -- an unchecked conversion in this case and we are all done.
12152 -- If we are within a child unit, check whether the type of the
12153 -- expression has an ancestor in a parent unit, in which case it
12154 -- belongs to its derivation class even if the ancestor is private.
12155 -- See RM 7.3.1 (5.2/3).
12159 -- Numeric types
12163 -- A universal fixed expression can be converted to any numeric type
12168 -- Also no need to check when in an instance or inlined body, because
12169 -- the legality has been established when the template was analyzed.
12170 -- Furthermore, numeric conversions may occur where only a private
12171 -- view of the operand type is visible at the instantiation point.
12172 -- This results in a spurious error if we check that the operand type
12173 -- is a numeric type.
12175 -- Note: in a previous version of this unit, the following tests were
12176 -- applied only for generated code (Comes_From_Source set to False),
12177 -- but in fact the test is required for source code as well, since
12178 -- this situation can arise in source code.
12183 -- Otherwise we need the conversion check
12185 else
12186 return Conversion_Check
12188 or else
12194 -- Array types
12200 then
12201 Conversion_Error_N
12205 else
12209 -- Ada 2005 (AI-251): Internally generated conversions of access to
12210 -- interface types added to force the displacement of the pointer to
12211 -- reference the corresponding dispatch table.
12216 then
12219 -- Ada 2005 (AI-251): Anonymous access types where target references an
12220 -- interface type.
12224 E_Anonymous_Access_Type)
12226 then
12227 -- Check the static accessibility rule of 4.6(17). Note that the
12228 -- check is not enforced when within an instance body, since the
12229 -- RM requires such cases to be caught at run time.
12231 -- If the operand is a rewriting of an allocator no check is needed
12232 -- because there are no accessibility issues.
12240 then
12241 -- In an instance, this is a run-time check, but one we know
12242 -- will fail, so generate an appropriate warning. The raise
12243 -- will be generated by Expand_N_Type_Conversion.
12247 Conversion_Error_N
12249 Operand);
12252 else
12253 Conversion_Error_N
12255 Operand);
12259 -- Special accessibility checks are needed in the case of access
12260 -- discriminants declared for a limited type.
12264 then
12265 -- When the operand is a selected access discriminant the check
12266 -- needs to be made against the level of the object denoted by
12267 -- the prefix of the selected name (Object_Access_Level handles
12268 -- checking the prefix of the operand for this case).
12273 then
12274 -- In an instance, this is a run-time check, but one we know
12275 -- will fail, so generate an appropriate warning. The raise
12276 -- will be generated by Expand_N_Type_Conversion.
12280 Conversion_Error_N
12285 -- Real error if not in instance body
12287 else
12288 Conversion_Error_N
12295 -- The case of a reference to an access discriminant from
12296 -- within a limited type declaration (which will appear as
12297 -- a discriminal) is always illegal because the level of the
12298 -- discriminant is considered to be deeper than any (nameable)
12299 -- access type.
12303 and then
12306 then
12307 Conversion_Error_N
12309 Operand);
12317 -- General and anonymous access types
12320 E_Anonymous_Access_Type)
12321 and then
12322 Conversion_Check
12324 and then not
12326 E_Access_Protected_Subprogram_Type),
12328 then
12331 then
12332 Conversion_Error_N
12337 -- Check the static accessibility rule of 4.6(17). Note that the
12338 -- check is not enforced when within an instance body, since the RM
12339 -- requires such cases to be caught at run time.
12344 N_Object_Declaration
12345 then
12346 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12347 -- conversions from an anonymous access type to a named general
12348 -- access type. Such conversions are not allowed in the case of
12349 -- access parameters and stand-alone objects of an anonymous
12350 -- access type. The implicit conversion case is recognized by
12351 -- testing that Comes_From_Source is False and that it's been
12352 -- rewritten. The Comes_From_Source test isn't sufficient because
12353 -- nodes in inlined calls to predefined library routines can have
12354 -- Comes_From_Source set to False. (Is there a better way to test
12355 -- for implicit conversions???)
12362 then
12365 -- Implicit conversions aren't allowed for objects of an
12366 -- anonymous access type, since such objects have nonstatic
12367 -- levels in Ada 2012.
12370 N_Object_Declaration
12371 then
12372 Conversion_Error_N
12377 -- Implicit conversions aren't allowed for anonymous access
12378 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12379 -- is done to exclude anonymous access results.
12383 N_Function_Specification,
12384 N_Procedure_Specification)
12385 then
12386 Conversion_Error_N
12391 -- This is a case where there's an enclosing object whose
12392 -- to which the "statically deeper than" relationship does
12393 -- not apply (such as an access discriminant selected from
12394 -- a dereference of an access parameter).
12398 then
12399 Conversion_Error_N
12404 -- In other cases, the level of the operand's type must be
12405 -- statically less deep than that of the target type, else
12406 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12410 then
12411 Conversion_Error_N
12420 then
12421 -- In an instance, this is a run-time check, but one we know
12422 -- will fail, so generate an appropriate warning. The raise
12423 -- will be generated by Expand_N_Type_Conversion.
12427 Conversion_Error_N
12429 Operand);
12432 -- If not in an instance body, this is a real error
12434 else
12435 -- Avoid generation of spurious error message
12438 Conversion_Error_N
12440 Operand);
12446 -- Special accessibility checks are needed in the case of access
12447 -- discriminants declared for a limited type.
12451 then
12452 -- When the operand is a selected access discriminant the check
12453 -- needs to be made against the level of the object denoted by
12454 -- the prefix of the selected name (Object_Access_Level handles
12455 -- checking the prefix of the operand for this case).
12460 then
12461 -- In an instance, this is a run-time check, but one we know
12462 -- will fail, so generate an appropriate warning. The raise
12463 -- will be generated by Expand_N_Type_Conversion.
12467 Conversion_Error_N
12472 -- If not in an instance body, this is a real error
12474 else
12475 Conversion_Error_N
12482 -- The case of a reference to an access discriminant from
12483 -- within a limited type declaration (which will appear as
12484 -- a discriminal) is always illegal because the level of the
12485 -- discriminant is considered to be deeper than any (nameable)
12486 -- access type.
12489 and then
12492 then
12493 Conversion_Error_N
12495 Operand);
12501 -- In the presence of limited_with clauses we have to use nonlimited
12502 -- views, if available.
12506 -- Helper function to handle limited views
12508 --------------------------
12509 -- Full_Designated_Type --
12510 --------------------------
12515 begin
12516 -- Handle the limited view of a type
12520 then
12522 else
12527 -- Local Declarations
12535 -- Start of processing for Check_Limited
12537 begin
12541 else
12543 Conversion_Error_NE
12548 -- Ada 2005 AI-384: legality rule is symmetric in both
12549 -- designated types. The conversion is legal (with possible
12550 -- constraint check) if either designated type is
12551 -- unconstrained.
12554 or else
12556 and then
12559 then
12560 -- Special case, if Value_Size has been used to make the
12561 -- sizes different, the conversion is not allowed even
12562 -- though the subtypes statically match.
12567 then
12568 Conversion_Error_NE
12571 Conversion_Error_NE
12576 -- Normal case where conversion is allowed
12578 else
12582 else
12583 Error_Msg_NE
12591 -- Access to subprogram types. If the operand is an access parameter,
12592 -- the type has a deeper accessibility that any master, and cannot be
12593 -- assigned. We must make an exception if the conversion is part of an
12594 -- assignment and the target is the return object of an extended return
12595 -- statement, because in that case the accessibility check takes place
12596 -- after the return.
12600 -- Note: this test of Opnd_Type is there to prevent entering this
12601 -- branch in the case of a remote access to subprogram type, which
12602 -- is internally represented as an E_Record_Type.
12605 then
12609 and then
12613 then
12614 Conversion_Error_N
12616 Operand);
12617 Conversion_Error_N
12620 Operand);
12622 Error_Msg_NE
12627 -- Check that the designated types are subtype conformant
12633 -- Check the static accessibility rule of 4.6(20)
12637 then
12638 Conversion_Error_N
12640 Operand);
12642 -- Check that if the operand type is declared in a generic body,
12643 -- then the target type must be declared within that same body
12644 -- (enforces last sentence of 4.6(20)).
12647 declare
12653 begin
12660 Conversion_Error_N
12669 -- Remote access to subprogram types
12673 then
12674 -- It is valid to convert from one RAS type to another provided
12675 -- that their specification statically match.
12677 -- Note: at this point, remote access to subprogram types have been
12678 -- expanded to their E_Record_Type representation, and we need to
12679 -- go back to the original access type definition using the
12680 -- Corresponding_Remote_Type attribute in order to check that the
12681 -- designated profiles match.
12686 Check_Subtype_Conformant
12689 Old_Id =>
12691 Err_Loc =>
12692 N);
12695 -- If it was legal in the generic, it's legal in the instance
12700 -- If both are tagged types, check legality of view conversions
12703 and then
12705 then
12708 -- Types derived from the same root type are convertible
12713 -- In an instance or an inlined body, there may be inconsistent views of
12714 -- the same type, or of types derived from a common root.
12717 and then
12720 then
12723 -- Special check for common access type error case
12727 then
12729 Conversion_Error_NE -- CODEFIX
12733 -- Here we have a real conversion error
12735 else
12736 Conversion_Error_NE