| blob | af1a4e7b32e0f1469086eace199009180b772614 |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2017, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
86 -----------------------
87 -- Local Subprograms --
88 -----------------------
90 -- Second pass (top-down) type checking and overload resolution procedures
91 -- Typ is the type required by context. These procedures propagate the
92 -- type information recursively to the descendants of N. If the node is not
93 -- overloaded, its Etype is established in the first pass. If overloaded,
94 -- the Resolve routines set the correct type. For arithmetic operators, the
95 -- Etype is the base type of the context.
97 -- Note that Resolve_Attribute is separated off in Sem_Attr
100 -- Enforce the restrictions on the use of discriminants when constraining
101 -- a component of a discriminated type (record or concurrent type).
104 -- Given a node for an operator associated with type T, check that the
105 -- operator is visible. Operators all of whose operands are universal must
106 -- be checked for visibility during resolution because their type is not
107 -- determinable based on their operands.
109 procedure Check_Fully_Declared_Prefix
112 -- Check that the type of the prefix of a dereference is not incomplete
115 -- Given a call node, N, which is known to occur immediately within the
116 -- subprogram being called, determines whether it is a detectable case of
117 -- an infinite recursion, and if so, outputs appropriate messages. Returns
118 -- True if an infinite recursion is detected, and False otherwise.
121 -- If the type of the object being initialized uses the secondary stack
122 -- directly or indirectly, create a transient scope for the call to the
123 -- init proc. This is because we do not create transient scopes for the
124 -- initialization of individual components within the init proc itself.
125 -- Could be optimized away perhaps?
128 -- N is the node for a logical operator. If the operator is predefined, and
129 -- the root type of the operands is Standard.Boolean, then a check is made
130 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
131 -- the style check for Style_Check_Boolean_And_Or.
134 -- N is either an indexed component or a selected component. This function
135 -- returns true if the prefix refers to an object that has an address
136 -- clause (the case in which we may want to issue a warning).
139 -- Determine whether E is an access type declared by an access declaration,
140 -- and not an (anonymous) allocator type.
143 -- Utility to check whether the entity for an operator is a predefined
144 -- operator, in which case the expression is left as an operator in the
145 -- tree (else it is rewritten into a call). An instance of an intrinsic
146 -- conversion operation may be given an operator name, but is not treated
147 -- like an operator. Note that an operator that is an imported back-end
148 -- builtin has convention Intrinsic, but is expected to be rewritten into
149 -- a call, so such an operator is not treated as predefined by this
150 -- predicate.
153 -- If a default expression in entry call N depends on the discriminants
154 -- of the task, it must be replaced with a reference to the discriminant
155 -- of the task being called.
157 procedure Resolve_Op_Concat_Arg
162 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
163 -- concatenation operator. The operand is either of the array type or of
164 -- the component type. If the operand is an aggregate, and the component
165 -- type is composite, this is ambiguous if component type has aggregates.
168 -- Does the first part of the work of Resolve_Op_Concat
171 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
172 -- 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.
1445 else
1454 else
1463 then
1466 -- If the type is defined elsewhere, and the operator is not
1467 -- defined in the given scope (by a renaming declaration, e.g.)
1468 -- then this is an error as well. If an extension of System is
1469 -- present, and the type may be defined there, Pack must be
1470 -- System itself.
1477 then
1480 else
1486 then
1493 Error_Msg_NE
1498 -- Detect a mismatch between the context type and the result type
1499 -- in the named package, which is otherwise not detected if the
1500 -- operands are universal. Check is only needed if source entity is
1501 -- an operator, not a function that renames an operator.
1508 and then not In_Instance
1509 then
1512 then
1513 -- Already checked above
1517 -- Operator may be defined in an extension of System
1521 then
1524 else
1525 -- Could we use Wrong_Type here??? (this would require setting
1526 -- Etype (N) to the actual type found where Typ was expected).
1537 else
1541 -- If this is a call to a function that renames a predefined equality,
1542 -- the renaming declaration provides a type that must be used to
1543 -- resolve the operands. This must be done now because resolution of
1544 -- the equality node will not resolve any remaining ambiguity, and it
1545 -- assumes that the first operand is not overloaded.
1550 then
1558 -- Do rewrite setting Comes_From_Source on the result if the original
1559 -- call came from source. Although it is not strictly the case that the
1560 -- operator as such comes from the source, logically it corresponds
1561 -- exactly to the function call in the source, so it should be marked
1562 -- this way (e.g. to make sure that validity checks work fine).
1564 declare
1566 begin
1571 -- If this is an arithmetic operator and the result type is private,
1572 -- the operands and the result must be wrapped in conversion to
1573 -- expose the underlying numeric type and expand the proper checks,
1574 -- e.g. on division.
1578 when N_Op_Add
1579 | N_Op_Divide
1580 | N_Op_Expon
1581 | N_Op_Mod
1582 | N_Op_Multiply
1583 | N_Op_Rem
1584 | N_Op_Subtract
1585 =>
1588 when N_Op_Abs
1589 | N_Op_Minus
1590 | N_Op_Plus
1591 =>
1597 else
1601 -- If in ASIS_Mode, propagate operand types to original actuals of
1602 -- function call, which would otherwise not be fully resolved. If
1603 -- the call has already been constant-folded, nothing to do. We
1604 -- relocate the operand nodes rather than copy them, to preserve
1605 -- original_node pointers, given that the operands themselves may
1606 -- have been rewritten. If the call was itself a rewriting of an
1607 -- operator node, nothing to do.
1609 if ASIS_Mode
1612 then
1613 declare
1621 begin
1626 -- If the original call has named associations, replace the
1627 -- explicit actual parameter in the association with the proper
1628 -- resolved operand.
1633 then
1636 else
1641 else
1648 then
1651 else
1656 else
1660 else
1664 else
1674 -------------------
1675 -- Operator_Kind --
1676 -------------------
1678 function Operator_Kind
1681 is
1684 begin
1685 -- Use CASE statement or array???
1722 else
1726 -- Unary operators
1728 else
1737 else
1745 ----------------------------
1746 -- Preanalyze_And_Resolve --
1747 ----------------------------
1752 begin
1756 -- Normally, we suppress all checks for this preanalysis. There is no
1757 -- point in processing them now, since they will be applied properly
1758 -- and in the proper location when the default expressions reanalyzed
1759 -- and reexpanded later on. We will also have more information at that
1760 -- point for possible suppression of individual checks.
1762 -- However, in SPARK mode, most expansion is suppressed, and this
1763 -- later reanalysis and reexpansion may not occur. SPARK mode does
1764 -- require the setting of checking flags for proof purposes, so we
1765 -- do the SPARK preanalysis without suppressing checks.
1767 -- This special handling for SPARK mode is required for example in the
1768 -- case of Ada 2012 constructs such as quantified expressions, which are
1769 -- expanded in two separate steps.
1773 else
1777 Expander_Mode_Restore;
1781 -- Version without context type
1786 begin
1793 Expander_Mode_Restore;
1797 ----------------------------------
1798 -- Replace_Actual_Discriminants --
1799 ----------------------------------
1806 -- Comment needed???
1808 -------------------
1809 -- Process_Discr --
1810 -------------------
1815 begin
1821 then
1837 -- Start of processing for Replace_Actual_Discriminants
1839 begin
1853 else
1858 -------------
1859 -- Resolve --
1860 -------------
1876 -- Determine whether a node comes from a predefined library unit or
1877 -- Standard.
1880 -- Try and fix up a literal so that it matches its expected type. New
1881 -- literals are manufactured if necessary to avoid cascaded errors.
1884 -- Additional diagnostics when an ambiguous call has an ambiguous
1885 -- argument (typically a controlling actual).
1888 -- Called when attempt at resolving current expression fails
1890 ------------------------------------
1891 -- Comes_From_Predefined_Lib_Unit --
1892 -------------------------------------
1895 begin
1896 return
1900 --------------------
1901 -- Patch_Up_Value --
1902 --------------------
1905 begin
1922 then
1927 Char_Literal_Value =>
1943 -------------------------------
1944 -- Report_Ambiguous_Argument --
1945 -------------------------------
1952 begin
1956 then
1959 -- Could use comments on what is going on here???
1967 else
1976 -----------------------
1977 -- Resolution_Failed --
1978 -----------------------
1981 begin
1984 -- Set the type to the desired one to minimize cascaded errors. Note
1985 -- that this is an approximation and does not work in all cases.
1992 -- The caller will return without calling the expander, so we need
1993 -- to set the analyzed flag. Note that it is fine to set Analyzed
1994 -- to True even if we are in the middle of a shallow analysis,
1995 -- (see the spec of sem for more details) since this is an error
1996 -- situation anyway, and there is no point in repeating the
1997 -- analysis later (indeed it won't work to repeat it later, since
1998 -- we haven't got a clear resolution of which entity is being
1999 -- referenced.)
2005 -- Start of processing for Resolve
2007 begin
2012 -- Access attribute on remote subprogram cannot be used for a non-remote
2013 -- access-to-subprogram type.
2017 Name_Unrestricted_Access,
2018 Name_Unchecked_Access)
2024 then
2025 Error_Msg_N
2031 -- If the context is a Remote_Access_To_Subprogram, access attributes
2032 -- must be resolved with the corresponding fat pointer. There is no need
2033 -- to check for the attribute name since the return type of an
2034 -- attribute is never a remote type.
2039 then
2040 declare
2048 begin
2049 -- Check that Typ is a remote access-to-subprogram type
2053 -- Prefix (N) must statically denote a remote subprogram
2054 -- declared in a package specification.
2058 Attr = Attribute_Unrestricted_Access
2059 then
2074 or else
2076 then
2078 Error_Msg_N
2080 N);
2083 -- If we are generating code in distributed mode, perform
2084 -- semantic checks against corresponding remote entities.
2086 if Expander_Active
2088 then
2089 Check_Subtype_Conformant
2091 Old_Id => Designated_Type
2117 then
2122 -- Return if already analyzed
2129 -- Any case of Any_Type as the Etype value means that we had a
2130 -- previous error.
2139 -- The resolution of an Expression_With_Actions is determined by
2140 -- its Expression.
2148 -- If not overloaded, then we know the type, and all that needs doing
2149 -- is to check that this type is compatible with the context.
2155 -- In the overloaded case, we must select the interpretation that
2156 -- is compatible with the context (i.e. the type passed to Resolve)
2158 else
2159 -- Loop through possible interpretations
2168 -- We are only interested in interpretations that are compatible
2169 -- with the expected type, any other interpretations are ignored.
2174 Write_Eol;
2177 else
2178 -- Skip the current interpretation if it is disabled by an
2179 -- abstract operator. This action is performed only when the
2180 -- type against which we are resolving is the same as the
2181 -- type of the interpretation.
2188 then
2196 -- First matching interpretation
2204 -- Matching interpretation that is not the first, maybe an
2205 -- error, but there are some cases where preference rules are
2206 -- used to choose between the two possibilities. These and
2207 -- some more obscure cases are handled in Disambiguate.
2209 else
2210 -- If the current statement is part of a predefined library
2211 -- unit, then all interpretations which come from user level
2212 -- packages should not be considered. Check previous and
2213 -- current one.
2221 -- Previous interpretation must be discarded
2231 -- Otherwise apply further disambiguation steps
2236 -- Disambiguation has succeeded. Skip the remaining
2237 -- interpretations.
2247 else
2248 -- Before we issue an ambiguity complaint, check for the
2249 -- case of a subprogram call where at least one of the
2250 -- arguments is Any_Type, and if so suppress the message,
2251 -- since it is a cascaded error. This can also happen for
2252 -- a generalized indexing operation.
2257 then
2258 declare
2262 begin
2278 Write_Eol;
2291 then
2296 then
2300 -- Not that special case, so issue message using the flag
2301 -- Ambiguous to control printing of the header message
2302 -- only at the start of an ambiguous set.
2307 then
2308 Error_Msg_N
2311 else
2312 Error_Msg_NE -- CODEFIX
2320 Error_Msg_N
2322 else
2323 Error_Msg_N -- CODEFIX
2329 then
2330 Report_Ambiguous_Argument;
2336 -- By default, the error message refers to the candidate
2337 -- interpretation. But if it is a predefined operator, it
2338 -- is implicitly declared at the declaration of the type
2339 -- of the operand. Recover the sloc of that declaration
2340 -- for the error message.
2346 Standard_Standard
2347 then
2352 then
2360 Standard_Standard
2361 then
2366 then
2370 -- If this is an indirect call, use the subprogram_type
2371 -- in the message, to have a meaningful location. Also
2372 -- indicate if this is an inherited operation, created
2373 -- by a type declaration.
2378 then
2380 Error_Msg_Sloc :=
2382 else
2389 then
2390 -- Special-case the message for universal_fixed
2391 -- operators, which are not declared with the type
2392 -- of the operand, but appear forever in Standard.
2396 then
2397 Error_Msg_N
2400 else
2401 Error_Msg_N
2405 elsif
2407 then
2408 Error_Msg_N
2410 else
2411 Error_Msg_N -- CODEFIX
2418 -- We have a matching interpretation, Expr_Type is the type
2419 -- from this interpretation, and Seen is the entity.
2421 -- For an operator, just set the entity name. The type will be
2422 -- set by the specific operator resolution routine.
2437 -- AI05-0139-2: Expression is overloaded because type has
2438 -- implicit dereference. If type matches context, no implicit
2439 -- dereference is involved.
2450 then
2451 -- If the node is a general indexing, the dereference is
2452 -- is inserted when resolving the rewritten form, else
2453 -- insert it now.
2457 then
2461 -- For an explicit dereference, attribute reference, range,
2462 -- short-circuit form (which is not an operator node), or call
2463 -- with a name that is an explicit dereference, there is
2464 -- nothing to be done at this point.
2467 N_And_Then,
2468 N_Explicit_Dereference,
2469 N_Identifier,
2470 N_Indexed_Component,
2471 N_Or_Else,
2472 N_Range,
2473 N_Selected_Component,
2474 N_Slice)
2476 then
2479 -- For procedure or function calls, set the type of the name,
2480 -- and also the entity pointer for the prefix.
2484 then
2491 then
2496 -- For all other cases, just set the type of the Name
2498 else
2506 -- Move to next interpretation
2514 -- At this stage Found indicates whether or not an acceptable
2515 -- interpretation exists. If not, then we have an error, except that if
2516 -- the context is Any_Type as a result of some other error, then we
2517 -- suppress the error report.
2522 -- If type we are looking for is Void, then this is the procedure
2523 -- call case, and the error is simply that what we gave is not a
2524 -- procedure name (we think of procedure calls as expressions with
2525 -- types internally, but the user doesn't think of them this way).
2529 -- Special case message if function used as a procedure
2534 then
2535 Error_Msg_NE
2538 Error_Msg_N
2542 -- Otherwise give general message (not clear what cases this
2543 -- covers, but no harm in providing for them).
2545 else
2551 -- Otherwise we do have a subexpression with the wrong type
2553 -- Check for the case of an allocator which uses an access type
2554 -- instead of the designated type. This is a common error and we
2555 -- specialize the message, posting an error on the operand of the
2556 -- allocator, complaining that we expected the designated type of
2557 -- the allocator.
2563 then
2567 -- Check for view mismatch on Null in instances, for which the
2568 -- view-swapping mechanism has no identifier.
2574 then
2579 -- Check for an aggregate. Sometimes we can get bogus aggregates
2580 -- from misuse of parentheses, and we are about to complain about
2581 -- the aggregate without even looking inside it.
2583 -- Instead, if we have an aggregate of type Any_Composite, then
2584 -- analyze and resolve the component fields, and then only issue
2585 -- another message if we get no errors doing this (otherwise
2586 -- assume that the errors in the aggregate caused the problem).
2590 then
2591 -- Disable expansion in any case. If there is a type mismatch
2592 -- it may be fatal to try to expand the aggregate. The flag
2593 -- would otherwise be set to false when the error is posted.
2597 declare
2599 -- Check one aggregate, and set Found to True if we have a
2600 -- definite error in any of its elements
2603 -- Check one element of aggregate and set Found to True if
2604 -- we definitely have an error in the element.
2606 ----------------
2607 -- Check_Aggr --
2608 ----------------
2613 begin
2626 -- If this is a default-initialized component, then
2627 -- there is nothing to check. The box will be
2628 -- replaced by the appropriate call during late
2629 -- expansion.
2633 then
2642 ----------------
2643 -- Check_Elmt --
2644 ----------------
2647 begin
2648 -- If we have a nested aggregate, go inside it (to
2649 -- attempt a naked analyze-resolve of the aggregate can
2650 -- cause undesirable cascaded errors). Do not resolve
2651 -- expression if it needs a type from context, as for
2652 -- integer * fixed expression.
2657 else
2662 then
2672 begin
2677 -- Looks like we have a type error, but check for special case
2678 -- of Address wanted, integer found, with the configuration pragma
2679 -- Allow_Integer_Address active. If we have this case, introduce
2680 -- an unchecked conversion to allow the integer expression to be
2681 -- treated as an Address. The reverse case of integer wanted,
2682 -- Address found, is treated in an analogous manner.
2689 -- Under relaxed RM semantics silently replace occurrences of null
2690 -- by System.Address_Null.
2698 -- That special Allow_Integer_Address check did not apply, so we
2699 -- have a real type error. If an error message was issued already,
2700 -- Found got reset to True, so if it's still False, issue standard
2701 -- Wrong_Type message.
2705 declare
2708 begin
2714 -- Protected operation: retrieve operation name
2718 else
2723 Error_Msg_NE
2729 declare
2733 begin
2740 Error_Msg_NE
2746 else
2750 else
2756 Resolution_Failed;
2759 -- Test if we have more than one interpretation for the context
2762 Resolution_Failed;
2765 -- Only one intepretation
2767 else
2768 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2769 -- the "+" on T is abstract, and the operands are of universal type,
2770 -- the above code will have (incorrectly) resolved the "+" to the
2771 -- universal one in Standard. Therefore check for this case and give
2772 -- an error. We can't do this earlier, because it would cause legal
2773 -- cases to get errors (when some other type has an abstract "+").
2779 then
2784 then
2785 Error_Msg_NE
2794 -- Here we have an acceptable interpretation for the context
2796 -- Propagate type information and normalize tree for various
2797 -- predefined operations. If the context only imposes a class of
2798 -- types, rather than a specific type, propagate the actual type
2799 -- downward.
2805 Typ = Any_Discrete
2806 then
2809 -- Any_Fixed is legal in a real context only if a specific fixed-
2810 -- point type is imposed. If Norman Cohen can be confused by this,
2811 -- it deserves a separate message.
2815 then
2822 -- A user-defined operator is transformed into a function call at
2823 -- this point, so that further processing knows that operators are
2824 -- really operators (i.e. are predefined operators). User-defined
2825 -- operators that are intrinsic are just renamings of the predefined
2826 -- ones, and need not be turned into calls either, but if they rename
2827 -- a different operator, we must transform the node accordingly.
2828 -- Instantiations of Unchecked_Conversion are intrinsic but are
2829 -- treated as functions, even if given an operator designator.
2834 then
2839 and then
2841 N_Subprogram_Renaming_Declaration
2842 then
2845 -- If the node is rewritten, it will be fully resolved in
2846 -- Rewrite_Renamed_Operator.
2855 when N_Aggregate =>
2856 Resolve_Aggregate (N, Ctx_Type);
2858 when N_Allocator =>
2859 Resolve_Allocator (N, Ctx_Type);
2861 when N_Short_Circuit =>
2862 Resolve_Short_Circuit (N, Ctx_Type);
2864 when N_Attribute_Reference =>
2865 Resolve_Attribute (N, Ctx_Type);
2867 when N_Case_Expression =>
2868 Resolve_Case_Expression (N, Ctx_Type);
2870 when N_Character_Literal =>
2871 Resolve_Character_Literal (N, Ctx_Type);
2873 when N_Delta_Aggregate =>
2874 Resolve_Delta_Aggregate (N, Ctx_Type);
2876 when N_Expanded_Name =>
2877 Resolve_Entity_Name (N, Ctx_Type);
2879 when N_Explicit_Dereference =>
2880 Resolve_Explicit_Dereference (N, Ctx_Type);
2882 when N_Expression_With_Actions =>
2883 Resolve_Expression_With_Actions (N, Ctx_Type);
2885 when N_Extension_Aggregate =>
2886 Resolve_Extension_Aggregate (N, Ctx_Type);
2888 when N_Function_Call =>
2889 Resolve_Call (N, Ctx_Type);
2891 when N_Identifier =>
2892 Resolve_Entity_Name (N, Ctx_Type);
2894 when N_If_Expression =>
2895 Resolve_If_Expression (N, Ctx_Type);
2897 when N_Indexed_Component =>
2898 Resolve_Indexed_Component (N, Ctx_Type);
2900 when N_Integer_Literal =>
2901 Resolve_Integer_Literal (N, Ctx_Type);
2903 when N_Membership_Test =>
2904 Resolve_Membership_Op (N, Ctx_Type);
2906 when N_Null =>
2907 Resolve_Null (N, Ctx_Type);
2909 when N_Op_And
2910 | N_Op_Or
2911 | N_Op_Xor
2912 =>
2913 Resolve_Logical_Op (N, Ctx_Type);
2915 when N_Op_Eq
2916 | N_Op_Ne
2917 =>
2918 Resolve_Equality_Op (N, Ctx_Type);
2920 when N_Op_Ge
2921 | N_Op_Gt
2922 | N_Op_Le
2923 | N_Op_Lt
2924 =>
2925 Resolve_Comparison_Op (N, Ctx_Type);
2927 when N_Op_Not =>
2928 Resolve_Op_Not (N, Ctx_Type);
2930 when N_Op_Add
2931 | N_Op_Divide
2932 | N_Op_Mod
2933 | N_Op_Multiply
2934 | N_Op_Rem
2935 | N_Op_Subtract
2936 =>
2937 Resolve_Arithmetic_Op (N, Ctx_Type);
2939 when N_Op_Concat =>
2940 Resolve_Op_Concat (N, Ctx_Type);
2942 when N_Op_Expon =>
2943 Resolve_Op_Expon (N, Ctx_Type);
2945 when N_Op_Abs
2946 | N_Op_Minus
2947 | N_Op_Plus
2948 =>
2949 Resolve_Unary_Op (N, Ctx_Type);
2951 when N_Op_Shift =>
2952 Resolve_Shift (N, Ctx_Type);
2954 when N_Procedure_Call_Statement =>
2955 Resolve_Call (N, Ctx_Type);
2957 when N_Operator_Symbol =>
2958 Resolve_Operator_Symbol (N, Ctx_Type);
2960 when N_Qualified_Expression =>
2961 Resolve_Qualified_Expression (N, Ctx_Type);
2963 -- Why is the following null, needs a comment ???
2965 when N_Quantified_Expression =>
2966 null;
2968 when N_Raise_Expression =>
2969 Resolve_Raise_Expression (N, Ctx_Type);
2971 when N_Raise_xxx_Error =>
2972 Set_Etype (N, Ctx_Type);
2974 when N_Range =>
2975 Resolve_Range (N, Ctx_Type);
2977 when N_Real_Literal =>
2978 Resolve_Real_Literal (N, Ctx_Type);
2980 when N_Reference =>
2981 Resolve_Reference (N, Ctx_Type);
2983 when N_Selected_Component =>
2984 Resolve_Selected_Component (N, Ctx_Type);
2986 when N_Slice =>
2987 Resolve_Slice (N, Ctx_Type);
2989 when N_String_Literal =>
2990 Resolve_String_Literal (N, Ctx_Type);
2992 when N_Target_Name =>
2993 Resolve_Target_Name (N, Ctx_Type);
2995 when N_Type_Conversion =>
2996 Resolve_Type_Conversion (N, Ctx_Type);
2998 when N_Unchecked_Expression =>
2999 Resolve_Unchecked_Expression (N, Ctx_Type);
3001 when N_Unchecked_Type_Conversion =>
3002 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3003 end case;
3005 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3006 -- expression of an anonymous access type that occurs in the context
3007 -- of a named general access type, except when the expression is that
3008 -- of a membership test. This ensures proper legality checking in
3009 -- terms of allowed conversions (expressions that would be illegal to
3010 -- convert implicitly are allowed in membership tests).
3012 if Ada_Version >= Ada_2012
3013 and then Ekind (Ctx_Type) = E_General_Access_Type
3014 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3015 and then Nkind (Parent (N)) not in N_Membership_Test
3016 then
3017 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3018 Analyze_And_Resolve (N, Ctx_Type);
3019 end if;
3021 -- If the subexpression was replaced by a non-subexpression, then
3022 -- all we do is to expand it. The only legitimate case we know of
3023 -- is converting procedure call statement to entry call statements,
3024 -- but there may be others, so we are making this test general.
3026 if Nkind (N) not in N_Subexpr then
3027 Debug_A_Exit ("resolving ", N, " (done)");
3028 Expand (N);
3029 return;
3030 end if;
3032 -- The expression is definitely NOT overloaded at this point, so
3033 -- we reset the Is_Overloaded flag to avoid any confusion when
3034 -- reanalyzing the node.
3036 Set_Is_Overloaded (N, False);
3038 -- Freeze expression type, entity if it is a name, and designated
3039 -- type if it is an allocator (RM 13.14(10,11,13)).
3041 -- Now that the resolution of the type of the node is complete, and
3042 -- we did not detect an error, we can expand this node. We skip the
3043 -- expand call if we are in a default expression, see section
3044 -- "Handling of Default Expressions" in Sem spec.
3046 Debug_A_Exit ("resolving ", N, " (done)");
3048 -- We unconditionally freeze the expression, even if we are in
3049 -- default expression mode (the Freeze_Expression routine tests this
3050 -- flag and only freezes static types if it is set).
3052 -- Ada 2012 (AI05-177): The declaration of an expression function
3053 -- does not cause freezing, but we never reach here in that case.
3054 -- Here we are resolving the corresponding expanded body, so we do
3055 -- need to perform normal freezing.
3057 Freeze_Expression (N);
3059 -- Now we can do the expansion
3061 Expand (N);
3062 end if;
3063 end Resolve;
3065 -------------
3066 -- Resolve --
3067 -------------
3069 -- Version with check(s) suppressed
3071 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3072 begin
3073 if Suppress = All_Checks then
3074 declare
3075 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3076 begin
3077 Scope_Suppress.Suppress := (others => True);
3078 Resolve (N, Typ);
3079 Scope_Suppress.Suppress := Sva;
3080 end;
3082 else
3083 declare
3084 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3085 begin
3086 Scope_Suppress.Suppress (Suppress) := True;
3087 Resolve (N, Typ);
3088 Scope_Suppress.Suppress (Suppress) := Svg;
3089 end;
3090 end if;
3091 end Resolve;
3093 -------------
3094 -- Resolve --
3095 -------------
3097 -- Version with implicit type
3099 procedure Resolve (N : Node_Id) is
3100 begin
3101 Resolve (N, Etype (N));
3102 end Resolve;
3104 ---------------------
3105 -- Resolve_Actuals --
3106 ---------------------
3108 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3109 Loc : constant Source_Ptr := Sloc (N);
3110 A : Node_Id;
3111 A_Id : Entity_Id;
3112 A_Typ : Entity_Id;
3113 F : Entity_Id;
3114 F_Typ : Entity_Id;
3115 Prev : Node_Id := Empty;
3116 Orig_A : Node_Id;
3117 Real_F : Entity_Id;
3119 Real_Subp : Entity_Id;
3120 -- If the subprogram being called is an inherited operation for
3121 -- a formal derived type in an instance, Real_Subp is the subprogram
3122 -- that will be called. It may have different formal names than the
3123 -- operation of the formal in the generic, so after actual is resolved
3124 -- the name of the actual in a named association must carry the name
3125 -- of the actual of the subprogram being called.
3127 procedure Check_Aliased_Parameter;
3128 -- Check rules on aliased parameters and related accessibility rules
3129 -- in (RM 3.10.2 (10.2-10.4)).
3131 procedure Check_Argument_Order;
3132 -- Performs a check for the case where the actuals are all simple
3133 -- identifiers that correspond to the formal names, but in the wrong
3134 -- order, which is considered suspicious and cause for a warning.
3136 procedure Check_Prefixed_Call;
3137 -- If the original node is an overloaded call in prefix notation,
3139 -- Try_Object_Operation has already verified that there is a valid
3140 -- interpretation, but the form of the actual can only be determined
3141 -- once the primitive operation is identified.
3144 -- Emit an error concerning the illegal usage of an effectively volatile
3145 -- object in interfering context (SPARK RM 7.13(12)).
3148 -- If the actual is missing in a call, insert in the actuals list
3149 -- an instance of the default expression. The insertion is always
3150 -- a named association.
3152 procedure Property_Error
3156 -- Emit an error concerning variable Var with entity Var_Id that has
3157 -- enabled property Prop_Nam when it acts as an actual parameter in a
3158 -- call and the corresponding formal parameter is of mode IN.
3161 -- Check whether T1 and T2, or their full views, are derived from a
3162 -- common type. Used to enforce the restrictions on array conversions
3163 -- of AI95-00246.
3166 -- Predicate to determine whether an actual that is a concatenation
3167 -- will be evaluated statically and does not need a transient scope.
3168 -- This must be determined before the actual is resolved and expanded
3169 -- because if needed the transient scope must be introduced earlier.
3171 -----------------------------
3172 -- Check_Aliased_Parameter --
3173 -----------------------------
3178 begin
3186 else
3193 -- In a generic body assume the worst for generic formals:
3194 -- they can have a constrained partial view (AI05-041).
3200 then
3203 else
3208 else
3220 then
3228 then
3229 Error_Msg_N
3235 --------------------------
3236 -- Check_Argument_Order --
3237 --------------------------
3240 begin
3241 -- Nothing to do if no parameters, or original node is neither a
3242 -- function call nor a procedure call statement (happens in the
3243 -- operator-transformed-to-function call case), or the call does
3244 -- not come from source, or this warning is off.
3246 if not Warn_On_Parameter_Order
3250 then
3254 declare
3257 begin
3258 -- Nothing to do if only one parameter
3264 -- Here if at least two arguments
3266 declare
3272 -- Set True if an out of order case is found
3274 begin
3275 -- Collect identifier names of actuals, fail if any actual is
3276 -- not a simple identifier, and record max length of name.
3282 else
3288 -- If we got this far, all actuals are identifiers and the list
3289 -- of their names is stored in the Actuals array.
3294 -- If we ran out of formals, that's odd, probably an error
3295 -- which will be detected elsewhere, but abandon the search.
3301 -- If name matches and is in order OK
3306 else
3307 -- If no match, see if it is elsewhere in list and if so
3308 -- flag potential wrong order if type is compatible.
3312 and then
3314 then
3320 -- No match
3328 -- If Formals left over, also probably an error, skip warning
3334 -- Here we give the warning if something was out of order
3337 Error_Msg_N
3344 -------------------------
3345 -- Check_Prefixed_Call --
3346 -------------------------
3355 begin
3356 -- Check whether the call is a prefixed call, with or without
3357 -- additional actuals.
3360 or else
3366 then
3369 then
3370 -- Introduce dereference on object in prefix
3372 New_A :=
3380 then
3381 -- Introduce an implicit 'Access in prefix
3384 Error_Msg_NE
3400 ---------------------------------------
3401 -- Flag_Effectively_Volatile_Objects --
3402 ---------------------------------------
3406 -- Determine whether arbitrary node N denotes an effectively volatile
3407 -- object and if it does, emit an error.
3409 -----------------
3410 -- Flag_Object --
3411 -----------------
3416 begin
3417 -- Do not consider nested function calls because they have already
3418 -- been processed during their own resolution.
3430 then
3431 Error_Msg_N
3443 -- Start of processing for Flag_Effectively_Volatile_Objects
3445 begin
3449 --------------------
3450 -- Insert_Default --
3451 --------------------
3457 begin
3458 -- Missing argument in call, nothing to insert
3463 else
3464 -- Note that we do a full New_Copy_Tree, so that any associated
3465 -- Itypes are properly copied. This may not be needed any more,
3466 -- but it does no harm as a safety measure. Defaults of a generic
3467 -- formal may be out of bounds of the corresponding actual (see
3468 -- cc1311b) and an additional check may be required.
3470 Actval :=
3471 New_Copy_Tree
3476 -- Propagate dimension information, if any.
3482 then
3488 then
3491 then
3492 -- If default is a real literal, do not introduce a
3493 -- conversion whose effect may depend on the run-time
3494 -- size of universal real.
3498 else
3509 -- Resolve aggregates with their base type, to avoid scope
3510 -- anomalies: the subtype was first built in the subprogram
3511 -- declaration, and the current call may be nested.
3515 else
3519 else
3522 -- See note above concerning aggregates
3526 then
3529 -- Resolve entities with their own type, which may differ from
3530 -- the type of a reference in a generic context (the view
3531 -- swapping mechanism did not anticipate the re-analysis of
3532 -- default values in calls).
3537 else
3542 -- If default is a tag indeterminate function call, propagate tag
3543 -- to obtain proper dispatching.
3547 then
3552 -- If the default expression raises constraint error, then just
3553 -- silently replace it with an N_Raise_Constraint_Error node, since
3554 -- we already gave the warning on the subprogram spec. If node is
3555 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3556 -- the warnings removal machinery.
3560 then
3568 Assoc :=
3573 -- Case of insertion is first named actual
3577 then
3584 else
3588 else
3592 -- Case of insertion is not first named actual
3594 else
3595 Set_Next_Named_Actual
3607 --------------------
3608 -- Property_Error --
3609 --------------------
3611 procedure Property_Error
3615 is
3616 begin
3618 Error_Msg_NE
3624 -------------------
3625 -- Same_Ancestor --
3626 -------------------
3632 begin
3635 then
3641 then
3648 --------------------------
3649 -- Static_Concatenation --
3650 --------------------------
3653 begin
3660 -- Concatenation is static when both operands are static and
3661 -- the concatenation operator is a predefined one.
3664 and then
3666 and then
3671 declare
3673 begin
3676 and then
3680 else
3686 -- Start of processing for Resolve_Actuals
3688 begin
3689 Check_Argument_Order;
3693 and then In_Instance
3696 then
3698 else
3703 Check_Prefixed_Call;
3717 -- If we have an error in any actual or formal, indicated by a type
3718 -- of Any_Type, then abandon resolution attempt, and set result type
3719 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3720 -- type is imposed from context.
3724 then
3731 -- Case where actual is present
3733 -- If the actual is an entity, generate a reference to it now. We
3734 -- do this before the actual is resolved, because a formal of some
3735 -- protected subprogram, or a task discriminant, will be rewritten
3736 -- during expansion, and the source entity reference may be lost.
3741 then
3747 then
3754 -- RM 6.4.1(12): For an out parameter that is passed by
3755 -- copy, the formal parameter object is created, and:
3757 -- * For an access type, the formal parameter is initialized
3758 -- from the value of the actual, without checking that the
3759 -- value satisfies any constraint, any predicate, or any
3760 -- exclusion of the null value.
3762 -- * For a scalar type that has the Default_Value aspect
3763 -- specified, the formal parameter is initialized from the
3764 -- value of the actual, without checking that the value
3765 -- satisfies any constraint or any predicate.
3766 -- I do not understand why this case is included??? this is
3767 -- not a case where an OUT parameter is treated as IN OUT.
3769 -- * For a composite type with discriminants or that has
3770 -- implicit initial values for any subcomponents, the
3771 -- behavior is as for an in out parameter passed by copy.
3773 -- Hence for these cases we generate the read reference now
3774 -- (the write reference will be generated later by
3775 -- Note_Possible_Modification).
3778 and then
3780 or else
3782 and then
3784 or else
3787 or else Is_Partially_Initialized_Type
3789 then
3799 then
3800 -- If style checking mode on, check match of formal name
3808 -- If the formal is Out or In_Out, do not resolve and expand the
3809 -- conversion, because it is subsequently expanded into explicit
3810 -- temporaries and assignments. However, the object of the
3811 -- conversion can be resolved. An exception is the case of tagged
3812 -- type conversion with a class-wide actual. In that case we want
3813 -- the tag check to occur and no temporary will be needed (no
3814 -- representation change can occur) and the parameter is passed by
3815 -- reference, so we go ahead and resolve the type conversion.
3816 -- Another exception is the case of reference to component or
3817 -- subcomponent of a bit-packed array, in which case we want to
3818 -- defer expansion to the point the in and out assignments are
3819 -- performed.
3824 then
3827 then
3828 -- In a view conversion, the conversion must be legal in
3829 -- both directions, and thus both component types must be
3830 -- aliased, or neither (4.6 (8)).
3832 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3833 -- the privacy requirement should not apply to generic
3834 -- types, and should be checked in an instance. ARG query
3835 -- is in order ???
3839 then
3840 Error_Msg_N
3844 -- Comment here??? what set of cases???
3846 elsif
3848 then
3849 -- Check view conv between unrelated by ref array types
3853 then
3854 Error_Msg_N
3858 -- In Ada 2005 mode, check view conversion component
3859 -- type cannot be private, tagged, or volatile. Note
3860 -- that we only apply this to source conversions. The
3861 -- generated code can contain conversions which are
3862 -- not subject to this test, and we cannot extract the
3863 -- component type in such cases since it is not present.
3867 then
3868 declare
3870 Component_Type
3872 begin
3877 then
3878 Error_Msg_N
3889 -- Resolve expression if conversion is all OK
3894 then
3898 -- If the actual is a function call that returns a limited
3899 -- unconstrained object that needs finalization, create a
3900 -- transient scope for it, so that it can receive the proper
3901 -- finalization list.
3906 and then Expander_Active
3908 then
3912 -- A small optimization: if one of the actuals is a concatenation
3913 -- create a block around a procedure call to recover stack space.
3914 -- This alleviates stack usage when several procedure calls in
3915 -- the same statement list use concatenation. We do not perform
3916 -- this wrapping for code statements, where the argument is a
3917 -- static string, and we want to preserve warnings involving
3918 -- sequences of such statements.
3922 and then Expander_Active
3923 and then
3927 then
3931 else
3935 and then
3938 then
3939 Error_Msg_N
3952 -- (Ada 2005: AI-251): If the actual is an allocator whose
3953 -- directly designated type is a class-wide interface, we build
3954 -- an anonymous access type to use it as the type of the
3955 -- allocator. Later, when the subprogram call is expanded, if
3956 -- the interface has a secondary dispatch table the expander
3957 -- will add a type conversion to force the correct displacement
3958 -- of the pointer.
3961 declare
3967 begin
3970 then
3973 Set_Directly_Designated_Type
3978 -- Ada 2005, AI-162:If the actual is an allocator, the
3979 -- innermost enclosing statement is the master of the
3980 -- created object. This needs to be done with expansion
3981 -- enabled only, otherwise the transient scope will not
3982 -- be removed in the expansion of the wrapped construct.
3985 and then Expander_Active
3986 then
3996 -- (Ada 2005): The call may be to a primitive operation of a
3997 -- tagged synchronized type, declared outside of the type. In
3998 -- this case the controlling actual must be converted to its
3999 -- corresponding record type, which is the formal type. The
4000 -- actual may be a subtype, either because of a constraint or
4001 -- because it is a generic actual, so use base type to locate
4002 -- concurrent type.
4009 then
4010 -- If the actual is overloaded, look for an interpretation
4011 -- that has a synchronized type.
4016 else
4017 declare
4021 begin
4026 then
4036 declare
4039 begin
4042 else
4046 -- Tagged synchronized type (case 1): the actual is a
4047 -- concurrent type.
4051 then
4053 Unchecked_Convert_To
4057 -- Tagged synchronized type (case 2): the formal is a
4058 -- concurrent type.
4061 and then Present
4066 then
4069 -- Common case
4071 else
4076 -- Not a synchronized operation
4078 else
4086 -- An actual cannot be an untagged formal incomplete type
4091 then
4092 Error_Msg_N
4098 N_Procedure_Call_Statement)
4099 then
4100 -- In formal mode, check that actual parameters matching
4101 -- formals of tagged types are objects (or ancestor type
4102 -- conversions of objects), not general expressions.
4109 declare
4114 begin
4116 Check_SPARK_05_Restriction
4119 -- In formal mode, the only view conversions are those
4120 -- involving ancestor conversion of an extended type.
4122 elsif not
4128 then
4129 if Ekind_In
4131 then
4132 Check_SPARK_05_Restriction
4135 else
4136 Check_SPARK_05_Restriction
4140 else
4145 else
4149 -- In formal mode, the only view conversions are those
4150 -- involving ancestor conversion of an extended type.
4154 then
4155 Check_SPARK_05_Restriction
4161 -- has warnings suppressed, then we reset Never_Set_In_Source for
4162 -- the calling entity. The reason for this is to catch cases like
4163 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4164 -- uses trickery to modify an IN parameter.
4171 then
4175 -- Perform error checks for IN and IN OUT parameters
4179 -- Check unset reference. For scalar parameters, it is clearly
4180 -- wrong to pass an uninitialized value as either an IN or
4181 -- IN-OUT parameter. For composites, it is also clearly an
4182 -- error to pass a completely uninitialized value as an IN
4183 -- parameter, but the case of IN OUT is trickier. We prefer
4184 -- not to give a warning here. For example, suppose there is
4185 -- a routine that sets some component of a record to False.
4186 -- It is perfectly reasonable to make this IN-OUT and allow
4187 -- either initialized or uninitialized records to be passed
4188 -- in this case.
4190 -- For partially initialized composite values, we also avoid
4191 -- warnings, since it is quite likely that we are passing a
4192 -- partially initialized value and only the initialized fields
4193 -- will in fact be read in the subprogram.
4198 then
4202 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4203 -- actual to a nested call, since this constitutes a reading of
4204 -- the parameter, which is not allowed.
4209 then
4214 -- In -gnatd.q mode, forget that a given array is constant when
4215 -- it is passed as an IN parameter to a foreign-convention
4216 -- subprogram. This is in case the subprogram evilly modifies the
4217 -- object. Of course, correct code would use IN OUT.
4219 if Debug_Flag_Dot_Q
4225 then
4229 -- Case of OUT or IN OUT parameter
4233 -- For an Out parameter, check for useless assignment. Note
4234 -- that we can't set Last_Assignment this early, because we may
4235 -- kill current values in Resolve_Call, and that call would
4236 -- clobber the Last_Assignment field.
4238 -- Note: call Warn_On_Useless_Assignment before doing the check
4239 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4240 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4241 -- reflects the last assignment, not this one.
4248 then
4253 -- Validate the form of the actual. Note that the call to
4254 -- Is_OK_Variable_For_Out_Formal generates the required
4255 -- reference in this case.
4257 -- A call to an initialization procedure for an aggregate
4258 -- component may initialize a nested component of a constant
4259 -- designated object. In this context the object is variable.
4263 then
4269 then
4270 Error_Msg_N
4275 Error_Msg_N
4282 -- What's the following about???
4286 else
4287 Kill_All_Checks;
4296 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4300 -- Apply predicate tests except in certain special cases. Note
4301 -- that it might be more consistent to apply these only when
4302 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4303 -- for the outbound predicate tests ??? In any case indicate
4304 -- the function being called, for better warnings if the call
4305 -- leads to an infinite recursion.
4311 -- Apply required constraint checks
4313 -- Gigi looks at the check flag and uses the appropriate types.
4314 -- For now since one flag is used there is an optimization
4315 -- which might not be done in the IN OUT case since Gigi does
4316 -- not do any analysis. More thought required about this ???
4318 -- In fact is this comment obsolete??? doesn't the expander now
4319 -- generate all these tests anyway???
4332 then
4335 -- For view conversions of a discriminated object, apply
4336 -- check to object itself, the conversion alreay has the
4337 -- proper type.
4341 then
4348 then
4354 then
4357 else
4361 -- Ada 2005 (AI-231): Note that the controlling parameter case
4362 -- already existed in Ada 95, which is partially checked
4363 -- elsewhere (see Checks), and we don't want the warning
4364 -- message to differ.
4369 then
4371 Apply_Compile_Time_Constraint_Error
4377 Apply_Compile_Time_Constraint_Error
4386 -- Checks for OUT parameters and IN OUT parameters
4390 -- If there is a type conversion, make sure the return value
4391 -- meets the constraints of the variable before the conversion.
4395 Apply_Scalar_Range_Check
4398 -- In addition, the returned value of the parameter must
4399 -- satisfy the bounds of the object type (see comment
4400 -- below).
4404 else
4405 Apply_Range_Check
4409 -- If no conversion, apply scalar range checks and length check
4410 -- based on the subtype of the actual (NOT that of the formal).
4411 -- This indicates that the check takes place on return from the
4412 -- call. During expansion the required constraint checks are
4413 -- inserted. In GNATprove mode, in the absence of expansion,
4414 -- the flag indicates that the returned value is valid.
4416 else
4422 then
4424 else
4429 -- Note: we do not apply the predicate checks for the case of
4430 -- OUT and IN OUT parameters. They are instead applied in the
4431 -- Expand_Actuals routine in Exp_Ch6.
4434 -- An actual associated with an access parameter is implicitly
4435 -- converted to the anonymous access type of the formal and must
4436 -- satisfy the legality checks for access conversions.
4440 Error_Msg_N
4444 -- If the actual is an access selected component of a variable,
4445 -- the call may modify its designated object. It is reasonable
4446 -- to treat this as a potential modification of the enclosing
4447 -- record, to prevent spurious warnings that it should be
4448 -- declared as a constant, because intuitively programmers
4449 -- regard the designated subcomponent as part of the record.
4454 then
4459 -- Check bad case of atomic/volatile argument (RM C.6(12))
4463 then
4466 then
4467 Error_Msg_NE
4473 then
4474 Error_Msg_NE
4480 -- Check that subprograms don't have improper controlling
4481 -- arguments (RM 3.9.2 (9)).
4483 -- A primitive operation may have an access parameter of an
4484 -- incomplete tagged type, but a dispatching call is illegal
4485 -- if the type is still incomplete.
4491 declare
4493 begin
4497 then
4498 Error_Msg_NE
4509 -- Apply legality rule 3.9.2 (9/1)
4514 and then not In_Instance
4515 then
4520 Error_Msg_NE
4524 -- Apply the checks described in 3.10.2(27): if the context is a
4525 -- specific access-to-object, the actual cannot be class-wide.
4526 -- Use base type to exclude access_to_subprogram cases.
4533 and then
4538 -- Disable these checks for call to imported C++ subprograms
4540 and then not
4544 then
4545 Error_Msg_N
4550 Error_Msg_NE
4555 Check_Aliased_Parameter;
4559 -- If it is a named association, treat the selector_name as a
4560 -- proper identifier, and mark the corresponding entity.
4564 -- Ignore reference in SPARK mode, as it refers to an entity not
4565 -- in scope at the point of reference, so the reference should
4566 -- be ignored for computing effects of subprograms.
4568 and then not GNATprove_Mode
4569 then
4570 -- If subprogram is overridden, use name of formal that
4571 -- is being called.
4577 else
4591 -- The following checks are only relevant when SPARK_Mode is on as
4592 -- they are not standard Ada legality rule. Internally generated
4593 -- temporaries are ignored.
4597 -- An effectively volatile object may act as an actual when the
4598 -- corresponding formal is of a non-scalar effectively volatile
4599 -- type (SPARK RM 7.1.3(11)).
4603 then
4606 -- An effectively volatile object may act as an actual in a
4607 -- call to an instance of Unchecked_Conversion.
4608 -- (SPARK RM 7.1.3(11)).
4613 -- The actual denotes an object
4616 Error_Msg_N
4620 -- Otherwise the actual denotes an expression. Inspect the
4621 -- expression and flag each effectively volatile object with
4622 -- enabled property Async_Writers or Effective_Reads as illegal
4623 -- because it apprears within an interfering context. Note that
4624 -- this is usually done in Resolve_Entity_Name, but when the
4625 -- effectively volatile object appears as an actual in a call,
4626 -- the call must be resolved first.
4628 else
4632 -- Detect an external variable with an enabled property that
4633 -- does not match the mode of the corresponding formal in a
4634 -- procedure call. Functions are not considered because they
4635 -- cannot have effectively volatile formal parameters in the
4636 -- first place.
4643 then
4656 -- A formal parameter of a specific tagged type whose related
4657 -- subprogram is subject to pragma Extensions_Visible with value
4658 -- "False" cannot act as an actual in a subprogram with value
4659 -- "True" (SPARK RM 6.1.7(3)).
4663 Extensions_Visible_True
4664 then
4665 Error_Msg_N
4668 Error_Msg_NE
4672 -- The actual parameter of a Ghost subprogram whose formal is of
4673 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4681 then
4682 Error_Msg_NE
4688 else
4695 -- Case where actual is not present
4697 else
4698 Insert_Default;
4709 -----------------------
4710 -- Resolve_Allocator --
4711 -----------------------
4723 procedure Check_Allocator_Discrim_Accessibility
4726 -- Check that accessibility level associated with an access discriminant
4727 -- initialized in an allocator by the expression Disc_Exp is not deeper
4728 -- than the level of the allocator type Alloc_Typ. An error message is
4729 -- issued if this condition is violated. Specialized checks are done for
4730 -- the cases of a constraint expression which is an access attribute or
4731 -- an access discriminant.
4734 -- If the allocator is an actual in a call, it is allowed to be class-
4735 -- wide when the context is not because it is a controlling actual.
4737 -------------------------------------------
4738 -- Check_Allocator_Discrim_Accessibility --
4739 -------------------------------------------
4741 procedure Check_Allocator_Discrim_Accessibility
4744 is
4745 begin
4748 then
4749 Error_Msg_N
4752 -- When the expression is an Access attribute the level of the prefix
4753 -- object must not be deeper than that of the allocator's type.
4757 Attribute_Access
4760 then
4761 Error_Msg_N
4763 Disc_Exp);
4765 -- When the expression is an access discriminant the check is against
4766 -- the level of the prefix object.
4772 then
4773 Error_Msg_N
4775 Disc_Exp);
4777 -- All other cases are legal
4779 else
4784 ----------------------------
4785 -- In_Dispatching_Context --
4786 ----------------------------
4791 begin
4797 -- Start of processing for Resolve_Allocator
4799 begin
4800 -- Replace general access with specific type
4810 -- For qualified expression, resolve the expression using the given
4811 -- subtype (nothing to do for type mark, subtype indication)
4816 and then not In_Dispatching_Context
4817 then
4818 Error_Msg_N
4826 -- Allocators generated by the build-in-place expansion mechanism
4827 -- are explicitly marked as coming from source but do not need to be
4828 -- checked for limited initialization. To exclude this case, ensure
4829 -- that the parent of the allocator is a source node.
4834 and then not In_Instance_Body
4835 then
4838 Error_Msg_N
4841 else
4842 Error_Msg_N
4850 -- A qualified expression requires an exact match of the type. Class-
4851 -- wide matching is not allowed.
4856 then
4860 -- Calls to build-in-place functions are not currently supported in
4861 -- allocators for access types associated with a simple storage pool.
4862 -- Supporting such allocators may require passing additional implicit
4863 -- parameters to build-in-place functions (or a significant revision
4864 -- of the current b-i-p implementation to unify the handling for
4865 -- multiple kinds of storage pools). ???
4869 then
4870 declare
4873 begin
4875 and then
4876 Present (Get_Rep_Pragma
4878 then
4879 Error_Msg_N
4886 -- A special accessibility check is needed for allocators that
4887 -- constrain access discriminants. The level of the type of the
4888 -- expression used to constrain an access discriminant cannot be
4889 -- deeper than the type of the allocator (in contrast to access
4890 -- parameters, where the level of the actual can be arbitrary).
4892 -- We can't use Valid_Conversion to perform this check because in
4893 -- general the type of the allocator is unrelated to the type of
4894 -- the access discriminant.
4898 then
4905 then
4908 -- Get the first component expression of the aggregate
4918 else
4922 else
4941 else
4946 else
4955 -- For a subtype mark or subtype indication, freeze the subtype
4957 else
4961 Error_Msg_N
4965 -- A special accessibility check is needed for allocators that
4966 -- constrain access discriminants. The level of the type of the
4967 -- expression used to constrain an access discriminant cannot be
4968 -- deeper than the type of the allocator (in contrast to access
4969 -- parameters, where the level of the actual can be arbitrary).
4970 -- We can't use Valid_Conversion to perform this check because
4971 -- in general the type of the allocator is unrelated to the type
4972 -- of the access discriminant.
4977 then
4987 else
5001 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5002 -- check that the level of the type of the created object is not deeper
5003 -- than the level of the allocator's access type, since extensions can
5004 -- now occur at deeper levels than their ancestor types. This is a
5005 -- static accessibility level check; a run-time check is also needed in
5006 -- the case of an initialized allocator with a class-wide argument (see
5007 -- Expand_Allocator_Expression).
5011 then
5012 declare
5015 begin
5020 else
5026 then
5029 Error_Msg_N
5038 -- Do not apply Ada 2005 accessibility checks on a class-wide
5039 -- allocator if the type given in the allocator is a formal
5040 -- type. A run-time check will be performed in the instance.
5050 -- Check for allocation from an empty storage pool
5055 -- If the context is an unchecked conversion, as may happen within an
5056 -- inlined subprogram, the allocator is being resolved with its own
5057 -- anonymous type. In that case, if the target type has a specific
5058 -- storage pool, it must be inherited explicitly by the allocator type.
5062 then
5063 Set_Associated_Storage_Pool
5071 -- Check that an allocator with task parts isn't for a nested access
5072 -- type when restriction No_Task_Hierarchy applies.
5076 then
5080 -- An illegal allocator may be rewritten as a raise Program_Error
5081 -- statement.
5085 -- An anonymous access discriminant is the definition of a
5086 -- coextension.
5090 N_Discriminant_Specification
5091 then
5092 declare
5096 begin
5099 -- Ada 2012 AI05-0052: If the designated type of the allocator
5100 -- is limited, then the allocator shall not be used to define
5101 -- the value of an access discriminant unless the discriminated
5102 -- type is immutably limited.
5107 then
5108 Error_Msg_N
5114 -- Avoid marking an allocator as a dynamic coextension if it is
5115 -- within a static construct.
5121 -- Cleanup for potential static coextensions
5123 else
5129 -- Report a simple error: if the designated object is a local task,
5130 -- its body has not been seen yet, and its activation will fail an
5131 -- elaboration check.
5138 then
5144 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5145 -- type with a task component on a subpool. This action must raise
5146 -- Program_Error at runtime.
5152 then
5164 ---------------------------
5165 -- Resolve_Arithmetic_Op --
5166 ---------------------------
5168 -- Used for resolving all arithmetic operators except exponentiation
5179 -- We do the resolution using the base type, because intermediate values
5180 -- in expressions always are of the base type, not a subtype of it.
5183 -- Returns True if N is in a context that expects "any real type"
5186 -- Return True iff given type is Integer or universal real/integer
5189 -- Choose type of integer literal in fixed-point operation to conform
5190 -- to available fixed-point type. T is the type of the other operand,
5191 -- which is needed to determine the expected type of N.
5194 -- Set operand type to T if universal
5196 -------------------------------
5197 -- Expected_Type_Is_Any_Real --
5198 -------------------------------
5201 begin
5202 -- N is the expression after "delta" in a fixed_point_definition;
5203 -- see RM-3.5.9(6):
5206 N_Decimal_Fixed_Point_Definition,
5208 -- N is one of the bounds in a real_range_specification;
5209 -- see RM-3.5.7(5):
5211 N_Real_Range_Specification,
5213 -- N is the expression of a delta_constraint;
5214 -- see RM-J.3(3):
5216 N_Delta_Constraint);
5219 -----------------------------
5220 -- Is_Integer_Or_Universal --
5221 -----------------------------
5228 begin
5234 else
5240 then
5251 ----------------------------
5252 -- Set_Mixed_Mode_Operand --
5253 ----------------------------
5259 begin
5262 -- A universal integer literal is resolved as standard integer
5263 -- except in the case of a fixed-point result, where we leave it
5264 -- as universal (to be handled by Exp_Fixd later on)
5268 else
5276 then
5277 -- A universal real can appear in a fixed-type context. We resolve
5278 -- the literal with that context, even though this might raise an
5279 -- exception prematurely (the other operand may be zero).
5286 then
5287 -- Integer arg in mixed-mode operation. Resolve with universal
5288 -- type, in case preference rule must be applied.
5294 then
5295 -- Not a mixed-mode operation, resolve with context
5301 -- N may itself be a mixed-mode operation, so use context type
5308 then
5309 -- Must be (fixed * fixed) operation, operand must have one
5310 -- compatible interpretation.
5317 then
5318 -- C * F(X) in a fixed context, where C is a real literal or a
5319 -- fixed-point expression. F must have either a fixed type
5320 -- interpretation or an integer interpretation, but not both.
5327 else
5334 else
5342 -- Reanalyze the literal with the fixed type of the context. If
5343 -- context is Universal_Fixed, we are within a conversion, leave
5344 -- the literal as a universal real because there is no usable
5345 -- fixed type, and the target of the conversion plays no role in
5346 -- the resolution.
5348 declare
5352 begin
5355 else
5361 then
5363 else
5371 -- A universal real conditional expression can appear in a fixed-type
5372 -- context and must be resolved with that context to facilitate the
5373 -- code generation to the backend.
5378 then
5381 else
5386 ----------------------
5387 -- Set_Operand_Type --
5388 ----------------------
5391 begin
5394 then
5399 -- Start of processing for Resolve_Arithmetic_Op
5401 begin
5406 then
5410 -- Special-case for mixed-mode universal expressions or fixed point type
5411 -- operation: each argument is resolved separately. The same treatment
5412 -- is required if one of the operands of a fixed point operation is
5413 -- universal real, since in this case we don't do a conversion to a
5414 -- specific fixed-point type (instead the expander handles the case).
5416 -- Set the type of the node to its universal interpretation because
5417 -- legality checks on an exponentiation operand need the context.
5422 then
5433 or else
5436 then
5441 -- If context is a fixed type and one operand is integer, the other
5442 -- is resolved with the type of the context.
5447 then
5454 then
5458 -- If both operands are universal and the context is a floating
5459 -- point type, the operands are resolved to the type of the context.
5465 else
5470 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5471 -- multiplying operators from being used when the expected type is
5472 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5473 -- some cases where the expected type is actually Any_Real;
5474 -- Expected_Type_Is_Any_Real takes care of that case.
5478 then
5482 N_Unchecked_Type_Conversion)
5483 then
5490 else
5493 and then not
5495 N_Unchecked_Type_Conversion)
5496 then
5497 Error_Msg_N
5502 -- The expected type is "any real type" in contexts like
5504 -- type T is delta <universal_fixed-expression> ...
5506 -- in which case we need to set the type to Universal_Real
5507 -- so that static expression evaluation will work properly.
5511 else
5521 then
5526 -- If no previous errors, this is only possible if one operand is
5527 -- overloaded and the context is universal. Resolve as such.
5532 else
5534 and then
5536 then
5540 -- If the context is Universal_Fixed and the operands are also
5541 -- universal fixed, this is an error, unless there is only one
5542 -- applicable fixed_point type (usually Duration).
5550 else
5555 else
5560 -- If one of the arguments was resolved to a non-universal type.
5561 -- label the result of the operation itself with the same type.
5562 -- Do the same for the universal argument, if any.
5574 -- In SPARK, a multiplication or division with operands of fixed point
5575 -- types must be qualified or explicitly converted to identify the
5576 -- result type.
5581 and then
5583 then
5584 Check_SPARK_05_Restriction
5588 -- Set overflow and division checking bit
5595 -- Give warning if explicit division by zero
5599 then
5605 or else
5608 then
5609 -- Specialize the warning message according to the operation.
5610 -- When SPARK_Mode is On, force a warning instead of an error
5611 -- in that case, as this likely corresponds to deactivated
5612 -- code. The following warnings are for the case
5617 -- For division, we have two cases, for float division
5618 -- of an unconstrained float type, on a machine where
5619 -- Machine_Overflows is false, we don't get an exception
5620 -- at run-time, but rather an infinity or Nan. The Nan
5621 -- case is pretty obscure, so just warn about infinities.
5625 and then not Machine_Overflows_On_Target
5626 then
5627 Error_Msg_N
5631 -- For all other cases, we get a Constraint_Error
5633 else
5634 Apply_Compile_Time_Constraint_Error
5641 Apply_Compile_Time_Constraint_Error
5647 Apply_Compile_Time_Constraint_Error
5652 -- Division by zero can only happen with division, rem,
5653 -- and mod operations.
5659 -- In GNATprove mode, we enable the division check so that
5660 -- GNATprove will issue a message if it cannot be proved.
5666 -- Otherwise just set the flag to check at run time
5668 else
5673 -- If Restriction No_Implicit_Conditionals is active, then it is
5674 -- violated if either operand can be negative for mod, or for rem
5675 -- if both operands can be negative.
5679 then
5680 declare
5687 -- Set if corresponding operand might be negative
5689 begin
5690 Determine_Range
5694 Determine_Range
5698 -- Check if we will be generating conditionals. There are two
5699 -- cases where that can happen, first for REM, the only case
5700 -- is largest negative integer mod -1, where the division can
5701 -- overflow, but we still have to give the right result. The
5702 -- front end generates a test for this annoying case. Here we
5703 -- just test if both operands can be negative (that's what the
5704 -- expander does, so we match its logic here).
5706 -- The second case is mod where either operand can be negative.
5707 -- In this case, the back end has to generate additional tests.
5710 or else
5712 then
5723 ------------------
5724 -- Resolve_Call --
5725 ------------------
5728 function Same_Or_Aliased_Subprograms
5731 -- Returns True if the subprogram entity S is the same as E or else
5732 -- S is an alias of E.
5734 ---------------------------------
5735 -- Same_Or_Aliased_Subprograms --
5736 ---------------------------------
5738 function Same_Or_Aliased_Subprograms
5741 is
5743 begin
5747 -- Local variables
5761 -- Start of processing for Resolve_Call
5763 begin
5764 -- The context imposes a unique interpretation with type Typ on a
5765 -- procedure or function call. Find the entity of the subprogram that
5766 -- yields the expected type, and propagate the corresponding formal
5767 -- constraints on the actuals. The caller has established that an
5768 -- interpretation exists, and emitted an error if not unique.
5770 -- First deal with the case of a call to an access-to-subprogram,
5771 -- dereference made explicit in Analyze_Call.
5777 else
5778 -- Find the interpretation whose type (a subprogram type) has a
5779 -- return type that is compatible with the context. Analysis of
5780 -- the node has established that one exists.
5799 -- If the prefix is not an entity, then resolve it
5805 -- For an indirect call, we always invalidate checks, since we do not
5806 -- know whether the subprogram is local or global. Yes we could do
5807 -- better here, e.g. by knowing that there are no local subprograms,
5808 -- but it does not seem worth the effort. Similarly, we kill all
5809 -- knowledge of current constant values.
5811 Kill_Current_Values;
5813 -- If this is a procedure call which is really an entry call, do
5814 -- the conversion of the procedure call to an entry call. Protected
5815 -- operations use the same circuitry because the name in the call
5816 -- can be an arbitrary expression with special resolution rules.
5821 then
5825 -- Kill checks and constant values, as above for indirect case
5826 -- Who knows what happens when another task is activated?
5828 Kill_Current_Values;
5831 -- Normal subprogram call with name established in Resolve
5837 -- Otherwise we must have the case of an overloaded call
5839 else
5842 -- Initialize Nam to prevent warning (we know it will be assigned
5843 -- in the loop below, but the compiler does not know that).
5863 then
5864 -- The prefix is a parameterless function call that returns an access
5865 -- to subprogram. If parameters are present in the current call, add
5866 -- add an explicit dereference. We use the base type here because
5867 -- within an instance these may be subtypes.
5869 -- The dereference is added either in Analyze_Call or here. Should
5870 -- be consolidated ???
5879 -- Check that a call to Current_Task does not occur in an entry body
5882 declare
5885 begin
5887 loop
5890 -- Exclude calls that occur within the default of a formal
5891 -- parameter of the entry, since those are evaluated outside
5892 -- of the body.
5899 then
5902 Error_Msg_NE
5916 -- Check that a procedure call does not occur in the context of the
5917 -- entry call statement of a conditional or timed entry call. Note that
5918 -- the case of a call to a subprogram renaming of an entry will also be
5919 -- rejected. The test for N not being an N_Entry_Call_Statement is
5920 -- defensive, covering the possibility that the processing of entry
5921 -- calls might reach this point due to later modifications of the code
5922 -- above.
5927 then
5931 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5932 -- for a procedure_or_entry_call, the procedure_name or
5933 -- procedure_prefix of the procedure_call_statement shall denote
5934 -- an entry renamed by a procedure, or (a view of) a primitive
5935 -- subprogram of a limited interface whose first parameter is
5936 -- a controlling parameter.
5941 then
5942 Error_Msg_N
5947 -- If the SPARK_05 restriction is active, we are not allowed
5948 -- to have a call to a subprogram before we see its completion.
5953 -- Don't flag strange internal calls
5958 -- Only flag calls in extended main source
5963 -- Exclude enumeration literals from this processing
5966 then
5967 Check_SPARK_05_Restriction
5971 -- Check that this is not a call to a protected procedure or entry from
5972 -- within a protected function.
5976 -- Freeze the subprogram name if not in a spec-expression. Note that
5977 -- we freeze procedure calls as well as function calls. Procedure calls
5978 -- are not frozen according to the rules (RM 13.14(14)) because it is
5979 -- impossible to have a procedure call to a non-frozen procedure in
5980 -- pure Ada, but in the code that we generate in the expander, this
5981 -- rule needs extending because we can generate procedure calls that
5982 -- need freezing.
5984 -- In Ada 2012, expression functions may be called within pre/post
5985 -- conditions of subsequent functions or expression functions. Such
5986 -- calls do not freeze when they appear within generated bodies,
5987 -- (including the body of another expression function) which would
5988 -- place the freeze node in the wrong scope. An expression function
5989 -- is frozen in the usual fashion, by the appearance of a real body,
5990 -- or at the end of a declarative part.
5993 and then not In_Spec_Expression
5995 and then
5998 then
6002 -- For a predefined operator, the type of the result is the type imposed
6003 -- by context, except for a predefined operation on universal fixed.
6004 -- Otherwise The type of the call is the type returned by the subprogram
6005 -- being called.
6012 -- If the subprogram returns an array type, and the context requires the
6013 -- component type of that array type, the node is really an indexing of
6014 -- the parameterless call. Resolve as such. A pathological case occurs
6015 -- when the type of the component is an access to the array type. In
6016 -- this case the call is truly ambiguous. If the call is to an intrinsic
6017 -- subprogram, it can't be an indexed component. This check is necessary
6018 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6019 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6020 -- pointers to the same array), the compiler gets confused and does an
6021 -- infinite recursion.
6024 and then
6027 or else
6030 and then
6033 then
6034 declare
6039 begin
6042 then
6043 Error_Msg_N
6045 else
6048 -- The called entity may be an explicit dereference, in which
6049 -- case there is no entity to set.
6057 or else
6059 and then
6061 then
6064 -- Indexed call to a parameterless function
6066 Index_Node :=
6068 Prefix =>
6071 else
6072 -- An Ada 2005 prefixed call to a primitive operation
6073 -- whose first parameter is the prefix. This prefix was
6074 -- prepended to the parameter list, which is actually a
6075 -- list of indexes. Remove the prefix in order to build
6076 -- the proper indexed component.
6078 Index_Node :=
6080 Prefix =>
6083 Parameter_Associations =>
6084 New_List
6089 -- Preserve the parenthesis count of the node
6093 -- Since we are correcting a node classification error made
6094 -- by the parser, we call Replace rather than Rewrite.
6108 else
6109 -- If the called function is not declared in the main unit and it
6110 -- returns the limited view of type then use the available view (as
6111 -- is done in Try_Object_Operation) to prevent back-end confusion;
6112 -- for the function entity itself. The call must appear in a context
6113 -- where the nonlimited view is available. If the function entity is
6114 -- in the extended main unit then no action is needed, because the
6115 -- back end handles this case. In either case the type of the call
6116 -- is the nonlimited view.
6120 then
6127 else
6132 -- In the case where the call is to an overloaded subprogram, Analyze
6133 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6134 -- such a case Normalize_Actuals needs to be called once more to order
6135 -- the actuals correctly. Otherwise the call will have the ordering
6136 -- given by the last overloaded subprogram whether this is the correct
6137 -- one being called or not.
6144 -- In any case, call is fully resolved now. Reset Overload flag, to
6145 -- prevent subsequent overload resolution if node is analyzed again
6150 -- A Ghost entity must appear in a specific context
6156 -- If we are calling the current subprogram from immediately within its
6157 -- body, then that is the case where we can sometimes detect cases of
6158 -- infinite recursion statically. Do not try this in case restriction
6159 -- No_Recursion is in effect anyway, and do it only for source calls.
6164 -- Check violation of SPARK_05 restriction which does not permit
6165 -- a subprogram body to contain a call to the subprogram directly.
6169 then
6170 Check_SPARK_05_Restriction
6174 -- Issue warning for possible infinite recursion in the absence
6175 -- of the No_Recursion restriction.
6180 then
6181 -- Here we detected and flagged an infinite recursion, so we do
6182 -- not need to test the case below for further warnings. Also we
6183 -- are all done if we now have a raise SE node.
6189 -- If call is to immediately containing subprogram, then check for
6190 -- the case of a possible run-time detectable infinite recursion.
6192 else
6196 -- Although in general case, recursion is not statically
6197 -- checkable, the case of calling an immediately containing
6198 -- subprogram is easy to catch.
6202 -- If the recursive call is to a parameterless subprogram,
6203 -- then even if we can't statically detect infinite
6204 -- recursion, this is pretty suspicious, and we output a
6205 -- warning. Furthermore, we will try later to detect some
6206 -- cases here at run time by expanding checking code (see
6207 -- Detect_Infinite_Recursion in package Exp_Ch6).
6209 -- If the recursive call is within a handler, do not emit a
6210 -- warning, because this is a common idiom: loop until input
6211 -- is correct, catch illegal input in handler and restart.
6217 then
6218 -- For the case of a procedure call. We give the message
6219 -- only if the call is the first statement in a sequence
6220 -- of statements, or if all previous statements are
6221 -- simple assignments. This is simply a heuristic to
6222 -- decrease false positives, without losing too many good
6223 -- warnings. The idea is that these previous statements
6224 -- may affect global variables the procedure depends on.
6225 -- We also exclude raise statements, that may arise from
6226 -- constraint checks and are probably unrelated to the
6227 -- intended control flow.
6231 then
6232 declare
6234 begin
6238 N_Raise_Constraint_Error)
6239 then
6248 -- Do not give warning if we are in a conditional context
6250 declare
6252 begin
6258 then
6263 -- Here warning is to be issued
6279 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6283 -- If subprogram name is a predefined operator, it was given in
6284 -- functional notation. Replace call node with operator node, so
6285 -- that actuals can be resolved appropriately.
6293 then
6299 -- Create a transient scope if the resulting type requires it
6301 -- There are several notable exceptions:
6303 -- a) In init procs, the transient scope overhead is not needed, and is
6304 -- even incorrect when the call is a nested initialization call for a
6305 -- component whose expansion may generate adjust calls. However, if the
6306 -- call is some other procedure call within an initialization procedure
6307 -- (for example a call to Create_Task in the init_proc of the task
6308 -- run-time record) a transient scope must be created around this call.
6310 -- b) Enumeration literal pseudo-calls need no transient scope
6312 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6313 -- functions) do not use the secondary stack even though the return
6314 -- type may be unconstrained.
6316 -- d) Calls to a build-in-place function, since such functions may
6317 -- allocate their result directly in a target object, and cases where
6318 -- the result does get allocated in the secondary stack are checked for
6319 -- within the specialized Exp_Ch6 procedures for expanding those
6320 -- build-in-place calls.
6322 -- e) Calls to inlinable expression functions do not use the secondary
6323 -- stack (since the call will be replaced by its returned object).
6325 -- f) If the subprogram is marked Inline_Always, then even if it returns
6326 -- an unconstrained type the call does not require use of the secondary
6327 -- stack. However, inlining will only take place if the body to inline
6328 -- is already present. It may not be available if e.g. the subprogram is
6329 -- declared in a child instance.
6331 -- If this is an initialization call for a type whose construction
6332 -- uses the secondary stack, and it is not a nested call to initialize
6333 -- a component, we do need to create a transient scope for it. We
6334 -- check for this by traversing the type in Check_Initialization_Call.
6340 then
6347 then
6350 elsif Expander_Active
6353 and then
6355 or else
6357 then
6360 -- If the call appears within the bounds of a loop, it will
6361 -- be rewritten and reanalyzed, nothing left to do here.
6368 and then not Within_Init_Proc
6369 then
6373 -- A protected function cannot be called within the definition of the
6374 -- enclosing protected type, unless it is part of a pre/postcondition
6375 -- on another protected operation. This may appear in the entry wrapper
6376 -- created for an entry with preconditions.
6381 and then not In_Spec_Expression
6383 then
6384 Error_Msg_NE
6388 -- Propagate interpretation to actuals, and add default expressions
6389 -- where needed.
6394 -- Overloaded literals are rewritten as function calls, for purpose of
6395 -- resolution. After resolution, we can replace the call with the
6396 -- literal itself.
6402 -- Avoid validation, since it is a static function call
6408 -- If the subprogram is not global, then kill all saved values and
6409 -- checks. This is a bit conservative, since in many cases we could do
6410 -- better, but it is not worth the effort. Similarly, we kill constant
6411 -- values. However we do not need to do this for internal entities
6412 -- (unless they are inherited user-defined subprograms), since they
6413 -- are not in the business of molesting local values.
6415 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6416 -- kill all checks and values for calls to global subprograms. This
6417 -- takes care of the case where an access to a local subprogram is
6418 -- taken, and could be passed directly or indirectly and then called
6419 -- from almost any context.
6421 -- Note: we do not do this step till after resolving the actuals. That
6422 -- way we still take advantage of the current value information while
6423 -- scanning the actuals.
6425 -- We suppress killing values if we are processing the nodes associated
6426 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6427 -- type kills all the values as part of analyzing the code that
6428 -- initializes the dispatch tables.
6432 or else Suppress_Value_Tracking_On_Call
6437 then
6438 Kill_Current_Values;
6441 -- If we are warning about unread OUT parameters, this is the place to
6442 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6443 -- after the above call to Kill_Current_Values (since that call clears
6444 -- the Last_Assignment field of all local variables).
6449 then
6450 declare
6454 begin
6464 then
6474 -- If the subprogram is a primitive operation, check whether or not
6475 -- it is a correct dispatching call.
6479 then
6484 and then not In_Instance
6485 then
6489 -- If this is a dispatching call, generate the appropriate reference,
6490 -- for better source navigation in GPS.
6494 then
6497 -- Normal case, not a dispatching call: generate a call reference
6499 else
6507 -- Check for violation of restriction No_Specific_Termination_Handlers
6508 -- and warn on a potentially blocking call to Abort_Task.
6512 or else
6514 then
6521 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6522 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6523 -- need to check the second argument to determine whether it is an
6524 -- absolute or relative timing event.
6529 then
6533 -- Issue an error for a call to an eliminated subprogram. This routine
6534 -- will not perform the check if the call appears within a default
6535 -- expression.
6539 -- In formal mode, the primitive operations of a tagged type or type
6540 -- extension do not include functions that return the tagged type.
6546 then
6550 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6551 -- class-wide and the call dispatches on result in a context that does
6552 -- not provide a tag, the call raises Program_Error.
6555 and then In_Instance
6560 then
6561 -- Verify that none of the formals are controlling
6563 declare
6567 begin
6589 -- Check for calling a function with OUT or IN OUT parameter when the
6590 -- calling context (us right now) is not Ada 2012, so does not allow
6591 -- OUT or IN OUT parameters in function calls. Functions declared in
6592 -- a predefined unit are OK, as they may be called indirectly from a
6593 -- user-declared instantiation.
6599 then
6604 -- Check the dimensions of the actuals in the call. For function calls,
6605 -- propagate the dimensions from the returned type to N.
6609 -- All done, evaluate call and deal with elaboration issues
6614 -- In GNATprove mode, expansion is disabled, but we want to inline some
6615 -- subprograms to facilitate formal verification. Indirect calls through
6616 -- a subprogram type or within a generic cannot be inlined. Inlining is
6617 -- performed only for calls subject to SPARK_Mode on.
6619 if GNATprove_Mode
6622 and then not Inside_A_Generic
6623 then
6630 -- Nothing to do if the subprogram is not eligible for inlining in
6631 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6635 or else Debug_Flag_M
6636 then
6639 -- Calls cannot be inlined inside assertions, as GNATprove treats
6640 -- assertions as logic expressions. Only issue a message when the
6641 -- body has been seen, otherwise this leads to spurious messages
6642 -- on expression functions.
6646 Cannot_Inline
6650 -- Calls cannot be inlined inside default expressions
6653 Cannot_Inline
6656 -- Inlining should not be performed during pre-analysis
6660 -- Do not inline calls inside expression functions, as this
6661 -- would prevent interpreting them as logical formulas in
6662 -- GNATprove. Only issue a message when the body has been seen,
6663 -- otherwise this leads to spurious messages on callees that
6664 -- are themselves expression functions.
6667 and then Is_Expression_Function_Or_Completion
6669 then
6672 then
6673 Cannot_Inline
6678 -- With the one-pass inlining technique, a call cannot be
6679 -- inlined if the corresponding body has not been seen yet.
6682 Cannot_Inline
6685 -- Nothing to do if there is no body to inline, indicating that
6686 -- the subprogram is not suitable for inlining in GNATprove
6687 -- mode.
6692 -- Calls cannot be inlined inside potentially unevaluated
6693 -- expressions, as this would create complex actions inside
6694 -- expressions, that are not handled by GNATprove.
6697 Cannot_Inline
6701 -- Do not inline calls which would possibly lead to missing a
6702 -- type conversion check on an input parameter.
6705 Cannot_Inline
6709 -- Otherwise, inline the call
6711 else
6721 -----------------------------
6722 -- Resolve_Case_Expression --
6723 -----------------------------
6731 begin
6743 -- When the expression is of a scalar subtype different from the
6744 -- result subtype, then insert a conversion to ensure the generation
6745 -- of a constraint check.
6755 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6756 -- dynamically tagged must be known statically.
6764 Error_Msg_N
6778 -------------------------------
6779 -- Resolve_Character_Literal --
6780 -------------------------------
6786 begin
6787 -- Verify that the character does belong to the type of the context
6792 -- Wide_Wide_Character literals must always be defined, since the set
6793 -- of wide wide character literals is complete, i.e. if a character
6794 -- literal is accepted by the parser, then it is OK for wide wide
6795 -- character (out of range character literals are rejected).
6800 -- Always accept character literal for type Any_Character, which
6801 -- occurs in error situations and in comparisons of literals, both
6802 -- of which should accept all literals.
6807 -- For Standard.Character or a type derived from it, check that the
6808 -- literal is in range.
6815 -- For Standard.Wide_Character or a type derived from it, check that the
6816 -- literal is in range.
6823 -- If the entity is already set, this has already been resolved in a
6824 -- generic context, or comes from expansion. Nothing else to do.
6829 -- Otherwise we have a user defined character type, and we can use the
6830 -- standard visibility mechanisms to locate the referenced entity.
6832 else
6845 -- If we fall through, then the literal does not match any of the
6846 -- entries of the enumeration type. This isn't just a constraint error
6847 -- situation, it is an illegality (see RM 4.2).
6849 Error_Msg_NE
6853 ---------------------------
6854 -- Resolve_Comparison_Op --
6855 ---------------------------
6857 -- Context requires a boolean type, and plays no role in resolution.
6858 -- Processing identical to that for equality operators. The result type is
6859 -- the base type, which matters when pathological subtypes of booleans with
6860 -- limited ranges are used.
6867 begin
6868 -- If this is an intrinsic operation which is not predefined, use the
6869 -- types of its declared arguments to resolve the possibly overloaded
6870 -- operands. Otherwise the operands are unambiguous and specify the
6871 -- expected type.
6876 else
6887 -- Skip remaining processing if already set to Any_Type
6893 -- Deal with other error cases
6897 T = Any_Character
6898 then
6901 else
6909 -- Resolve the operands if types OK
6918 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6919 -- types or array types except String.
6922 Check_SPARK_05_Restriction
6927 then
6928 Check_SPARK_05_Restriction
6932 -- Check comparison on unordered enumeration
6936 Error_Msg_NE
6943 -- Evaluate the relation (note we do this after the above check since
6944 -- this Eval call may change N to True/False. Skip this evaluation
6945 -- inside assertions, in order to keep assertions as written by users
6946 -- for tools that rely on these, e.g. GNATprove for loop invariants.
6947 -- Except evaluation is still performed even inside assertions for
6948 -- comparisons between values of universal type, which are useless
6949 -- for static analysis tools, and not supported even by GNATprove.
6953 and then
6955 then
6960 -----------------------------------------
6961 -- Resolve_Discrete_Subtype_Indication --
6962 -----------------------------------------
6964 procedure Resolve_Discrete_Subtype_Indication
6967 is
6971 begin
6979 else
6989 Error_Msg_NE
6992 -- Rewrite the constraint as a range of Typ
6993 -- to allow compilation to proceed further.
7005 else
7009 -- Additionally, we must check that the bounds are compatible
7010 -- with the given subtype, which might be different from the
7011 -- type of the context.
7015 -- ??? If the above check statically detects a Constraint_Error
7016 -- it replaces the offending bound(s) of the range R with a
7017 -- Constraint_Error node. When the itype which uses these bounds
7018 -- is frozen the resulting call to Duplicate_Subexpr generates
7019 -- a new temporary for the bounds.
7021 -- Unfortunately there are other itypes that are also made depend
7022 -- on these bounds, so when Duplicate_Subexpr is called they get
7023 -- a forward reference to the newly created temporaries and Gigi
7024 -- aborts on such forward references. This is probably sign of a
7025 -- more fundamental problem somewhere else in either the order of
7026 -- itype freezing or the way certain itypes are constructed.
7028 -- To get around this problem we call Remove_Side_Effects right
7029 -- away if either bounds of R are a Constraint_Error.
7031 declare
7035 begin
7051 -------------------------
7052 -- Resolve_Entity_Name --
7053 -------------------------
7055 -- Used to resolve identifiers and expanded names
7058 function Is_Assignment_Or_Object_Expression
7061 -- Determine whether node Context denotes an assignment statement or an
7062 -- object declaration whose expression is node Expr.
7064 ----------------------------------------
7065 -- Is_Assignment_Or_Object_Expression --
7066 ----------------------------------------
7068 function Is_Assignment_Or_Object_Expression
7071 is
7072 begin
7074 N_Object_Declaration)
7076 then
7079 -- Check whether a construct that yields a name is the expression of
7080 -- an assignment statement or an object declaration.
7083 N_Explicit_Dereference,
7084 N_Indexed_Component,
7085 N_Selected_Component,
7086 N_Slice)
7088 or else
7090 N_Unchecked_Type_Conversion)
7092 then
7093 return
7094 Is_Assignment_Or_Object_Expression
7098 -- Otherwise the context is not an assignment statement or an object
7099 -- declaration.
7101 else
7106 -- Local variables
7111 -- Start of processing for Resolve_Entity_Name
7113 begin
7114 -- If garbage from errors, set to Any_Type and return
7121 -- Replace named numbers by corresponding literals. Note that this is
7122 -- the one case where Resolve_Entity_Name must reset the Etype, since
7123 -- it is currently marked as universal.
7133 -- For enumeration literals, we need to make sure that a proper style
7134 -- check is done, since such literals are overloaded, and thus we did
7135 -- not do a style check during the first phase of analysis.
7141 -- Case of (sub)type name appearing in a context where an expression
7142 -- is expected. This is legal if occurrence is a current instance.
7143 -- See RM 8.6 (17/3).
7149 -- Any other use is an error
7151 else
7152 Error_Msg_N
7156 -- Check discriminant use if entity is discriminant in current scope,
7157 -- i.e. discriminant of record or concurrent type currently being
7158 -- analyzed. Uses in corresponding body are unrestricted.
7163 then
7166 -- A parameterless generic function cannot appear in a context that
7167 -- requires resolution.
7172 -- In Ada 83 an OUT parameter cannot be read
7177 or else Is_Assignment_Or_Object_Expression
7180 then
7185 -- In all other cases, just do the possible static evaluation
7187 else
7188 -- A deferred constant that appears in an expression must have a
7189 -- completion, unless it has been removed by in-place expansion of
7190 -- an aggregate. A constant that is a renaming does not need
7191 -- initialization.
7197 and then not In_Spec_Expression
7200 then
7204 then
7206 else
7207 Error_Msg_N
7217 -- When the entity appears in a parameter association, retrieve the
7218 -- related subprogram call.
7226 -- The following checks are only relevant when SPARK_Mode is on as
7227 -- they are not standard Ada legality rules.
7231 -- An effectively volatile object subject to enabled properties
7232 -- Async_Writers or Effective_Reads must appear in non-interfering
7233 -- context (SPARK RM 7.1.3(12)).
7240 then
7241 SPARK_Msg_N
7246 -- Check for possible elaboration issues with respect to reads of
7247 -- variables. The act of renaming the variable is not considered a
7248 -- read as it simply establishes an alias.
7251 and then Dynamic_Elaboration_Checks
7253 then
7257 -- The variable may eventually become a constituent of a single
7258 -- protected/task type. Record the reference now and verify its
7259 -- legality when analyzing the contract of the variable
7260 -- (SPARK RM 9.3).
7267 -- A Ghost entity must appear in a specific context
7275 -------------------
7276 -- Resolve_Entry --
7277 -------------------
7289 -- If the bounds of the entry family being called depend on task
7290 -- discriminants, build a new index subtype where a discriminant is
7291 -- replaced with the value of the discriminant of the target task.
7292 -- The target task is the prefix of the entry name in the call.
7294 -----------------------
7295 -- Actual_Index_Type --
7296 -----------------------
7306 -- If the bound is given by a discriminant, replace with a reference
7307 -- to the discriminant of the same name in the target task. If the
7308 -- entry name is the target of a requeue statement and the entry is
7309 -- in the current protected object, the bound to be used is the
7310 -- discriminal of the object (see Apply_Range_Checks for details of
7311 -- the transformation).
7313 -----------------------------
7314 -- Actual_Discriminant_Ref --
7315 -----------------------------
7321 begin
7326 then
7332 then
7333 -- Note: here Bound denotes a discriminant of the corresponding
7334 -- record type tskV, whose discriminal is a formal of the
7335 -- init-proc tskVIP. What we want is the body discriminal,
7336 -- which is associated to the discriminant of the original
7337 -- concurrent type tsk.
7339 return New_Occurrence_Of
7342 else
7343 Ref :=
7353 -- Start of processing for Actual_Index_Type
7355 begin
7358 then
7361 else
7375 -- Start of processing for Resolve_Entry
7377 begin
7378 -- Find name of entry being called, and resolve prefix of name with its
7379 -- own type. The prefix can be overloaded, and the name and signature of
7380 -- the entry must be taken into account.
7384 -- Case of dealing with entry family within the current tasks
7388 else
7394 -- Entry call to an entry (or entry family) in the current task. This
7395 -- is legal even though the task will deadlock. Rewrite as call to
7396 -- current task.
7398 -- This can also be a call to an entry in an enclosing task. If this
7399 -- is a single task, we have to retrieve its name, because the scope
7400 -- of the entry is the task type, not the object. If the enclosing
7401 -- task is a task type, the identity of the task is given by its own
7402 -- self variable.
7404 -- Finally this can be a requeue on an entry of the same task or
7405 -- protected object.
7412 then
7413 -- S is an enclosing task or protected object. The concurrent
7414 -- declaration has been converted into a type declaration, and
7415 -- the object itself has an object declaration that follows
7416 -- the type in the same declarative part.
7428 -- Call to current task. Will be transformed into call to Self
7435 New_N :=
7438 Selector_Name =>
7445 then
7446 -- Use the entry name (which must be unique at this point) to find
7447 -- the prefix that returns the corresponding task/protected type.
7449 declare
7455 begin
7477 -- Up to this point the expression could have been the actual in a
7478 -- simple entry call, and be given by a named association.
7482 else
7488 ------------------------
7489 -- Resolve_Entry_Call --
7490 ------------------------
7502 begin
7503 -- We kill all checks here, because it does not seem worth the effort to
7504 -- do anything better, an entry call is a big operation.
7506 Kill_All_Checks;
7508 -- Processing of the name is similar for entry calls and protected
7509 -- operation calls. Once the entity is determined, we can complete
7510 -- the resolution of the actuals.
7512 -- The selector may be overloaded, in the case of a protected object
7513 -- with overloaded functions. The type of the context is used for
7514 -- resolution.
7519 then
7520 declare
7524 begin
7543 -- Simple entry or protected operation call
7556 -- Call to member of entry family
7563 -- We cannot in general check the maximum depth of protected entry calls
7564 -- at compile time. But we can tell that any protected entry call at all
7565 -- violates a specified nesting depth of zero.
7571 -- Use context type to disambiguate a protected function that can be
7572 -- called without actuals and that returns an array type, and where the
7573 -- argument list may be an indexing of the returned value.
7578 and then
7584 and then
7585 Covers
7588 then
7589 declare
7592 begin
7593 Index_Node :=
7595 Prefix =>
7599 -- Since we are correcting a node classification error made by the
7600 -- parser, we call Replace rather than Rewrite.
7613 then
7615 -- Note the entity being called before rewriting the call, so that
7616 -- it appears used at this point.
7620 -- Rewrite as call to the precondition wrapper, adding the task
7621 -- object to the list of actuals. If the call is to a member of an
7622 -- entry family, include the index as well.
7624 declare
7628 begin
7637 New_Call :=
7639 Name =>
7644 -- Preanalyze and resolve new call. Current procedure is called
7645 -- from Resolve_Call, after which expansion will take place.
7652 -- The operation name may have been overloaded. Order the actuals
7653 -- according to the formals of the resolved entity, and set the return
7654 -- type to that of the operation.
7661 -- Reset the Is_Overloaded flag, since resolution is now completed
7663 -- Simple entry call
7668 -- Call to a member of an entry family
7678 -- Create a call reference to the entry
7686 -- Verify that a procedure call cannot masquerade as an entry
7687 -- call where an entry call is expected.
7692 then
7697 then
7702 then
7707 -- After resolution, entry calls and protected procedure calls are
7708 -- changed into entry calls, for expansion. The structure of the node
7709 -- does not change, so it can safely be done in place. Protected
7710 -- function calls must keep their structure because they are
7711 -- subexpressions.
7715 -- A protected operation that is not a function may modify the
7716 -- corresponding object, and cannot apply to a constant. If this
7717 -- is an internal call, the prefix is the type itself.
7723 then
7724 Error_Msg_N
7726 Entry_Name);
7740 -- Protected functions can return on the secondary stack, in which
7741 -- case we must trigger the transient scope mechanism.
7743 elsif Expander_Active
7745 then
7750 -------------------------
7751 -- Resolve_Equality_Op --
7752 -------------------------
7754 -- Both arguments must have the same type, and the boolean context does
7755 -- not participate in the resolution. The first pass verifies that the
7756 -- interpretation is not ambiguous, and the type of the left argument is
7757 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7758 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7759 -- though they carry a single (universal) type. Diagnose this case here.
7767 -- The resolution rule for if expressions requires that each such must
7768 -- have a unique type. This means that if several dependent expressions
7769 -- are of a non-null anonymous access type, and the context does not
7770 -- impose an expected type (as can be the case in an equality operation)
7771 -- the expression must be rejected.
7774 -- Attempt to explain the nature of a redundant comparison with True. If
7775 -- the expression N is too complex, this routine issues a general error
7776 -- message.
7779 -- In the case of allocators and access attributes, the context must
7780 -- provide an indication of the specific access type to be used. If
7781 -- one operand is of such a "generic" access type, check whether there
7782 -- is a specific visible access type that has the same designated type.
7783 -- This is semantically dubious, and of no interest to any real code,
7784 -- but c48008a makes it all worthwhile.
7786 -------------------------
7787 -- Check_If_Expression --
7788 -------------------------
7794 begin
7801 then
7807 ------------------------
7808 -- Explain_Redundancy --
7809 ------------------------
7816 begin
7819 -- Strip the operand down to an entity
7821 loop
7824 else
7829 -- The construct denotes an entity
7834 -- Do not generate an error message when the comparison is done
7835 -- against the enumeration literal Standard.True.
7839 -- Build a customized error message
7866 -- The construct is too complex to disect, issue a general message
7868 else
7873 -----------------------------
7874 -- Find_Unique_Access_Type --
7875 -----------------------------
7882 begin
7884 E_Access_Attribute_Type)
7885 then
7889 E_Access_Attribute_Type)
7890 then
7892 else
7904 then
7917 -- Start of processing for Resolve_Equality_Op
7919 begin
7930 T = Any_Character
7931 then
7934 else
7943 then
7952 -- If expressions must have a single type, and if the context does
7953 -- not impose one the dependent expressions cannot be anonymous
7954 -- access types.
7956 -- Why no similar processing for case expressions???
7960 E_Anonymous_Access_Subprogram_Type)
7962 E_Anonymous_Access_Subprogram_Type)
7963 then
7971 -- In SPARK, equality operators = and /= for array types other than
7972 -- String are only defined when, for each index position, the
7973 -- operands have equal static bounds.
7977 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7978 -- operation if not needed.
7986 then
7987 Check_SPARK_05_Restriction
7992 -- If the unique type is a class-wide type then it will be expanded
7993 -- into a dispatching call to the predefined primitive. Therefore we
7994 -- check here for potential violation of such restriction.
8000 -- Only warn for redundant equality comparison to True for objects
8001 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8002 -- other expressions, it may be a matter of preference to write
8003 -- "Expr = True" or "Expr".
8005 if Warn_On_Redundant_Constructs
8010 and then
8012 or else
8014 then
8015 Error_Msg_N -- CODEFIX
8025 -- If this is an inequality, it may be the implicit inequality
8026 -- created for a user-defined operation, in which case the corres-
8027 -- ponding equality operation is not intrinsic, and the operation
8028 -- cannot be constant-folded. Else fold.
8033 or else Is_Intrinsic_Subprogram
8035 then
8041 then
8045 -- Ada 2005: If one operand is an anonymous access type, convert the
8046 -- other operand to it, to ensure that the underlying types match in
8047 -- the back-end. Same for access_to_subprogram, and the conversion
8048 -- verifies that the types are subtype conformant.
8050 -- We apply the same conversion in the case one of the operands is a
8051 -- private subtype of the type of the other.
8053 -- Why the Expander_Active test here ???
8055 if Expander_Active
8056 and then
8058 E_Anonymous_Access_Subprogram_Type)
8060 then
8080 ----------------------------------
8081 -- Resolve_Explicit_Dereference --
8082 ----------------------------------
8090 -- The candidate prefix type, if overloaded
8095 begin
8099 -- A useful optimization: check whether the dereference denotes an
8100 -- element of a container, and if so rewrite it as a call to the
8101 -- corresponding Element function.
8103 -- Disabled for now, on advice of ARG. A more restricted form of the
8104 -- predicate might be acceptable ???
8106 -- if Is_Container_Element (N) then
8107 -- return;
8108 -- end if;
8112 -- Use the context type to select the prefix that has the correct
8113 -- designated type. Keep the first match, which will be the inner-
8114 -- most.
8121 then
8126 -- Remove access types that do not match, but preserve access
8127 -- to subprogram interpretations, in case a further dereference
8128 -- is needed (see below).
8141 else
8142 -- If no interpretation covers the designated type of the prefix,
8143 -- this is the pathological case where not all implementations of
8144 -- the prefix allow the interpretation of the node as a call. Now
8145 -- that the expected type is known, Remove other interpretations
8146 -- from prefix, rewrite it as a call, and resolve again, so that
8147 -- the proper call node is generated.
8158 New_N :=
8160 Name =>
8171 -- If not overloaded, resolve P with its own type
8173 else
8177 -- If the prefix might be null, add an access check
8181 then
8185 -- If the designated type is a packed unconstrained array type, and the
8186 -- explicit dereference is not in the context of an attribute reference,
8187 -- then we must compute and set the actual subtype, since it is needed
8188 -- by Gigi. The reason we exclude the attribute case is that this is
8189 -- handled fine by Gigi, and in fact we use such attributes to build the
8190 -- actual subtype. We also exclude generated code (which builds actual
8191 -- subtypes directly if they are needed).
8198 then
8204 -- Note: No Eval processing is required for an explicit dereference,
8205 -- because such a name can never be static.
8209 -------------------------------------
8210 -- Resolve_Expression_With_Actions --
8211 -------------------------------------
8214 begin
8217 -- If N has no actions, and its expression has been constant folded,
8218 -- then rewrite N as just its expression. Note, we can't do this in
8219 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8220 -- Expression (N) to be expanded again.
8224 then
8229 ----------------------------------
8230 -- Resolve_Generalized_Indexing --
8231 ----------------------------------
8239 begin
8240 -- In ASIS mode, propagate the information about the indexes back to
8241 -- to the original indexing node. The generalized indexing is either
8242 -- a function call, or a dereference of one. The actuals include the
8243 -- prefix of the original node, which is the container expression.
8252 loop
8261 -- If expression is to be reanalyzed, reset Generalized_Indexing
8262 -- to recreate call node, as is the case when the expression is
8263 -- part of an expression function.
8272 else
8278 ---------------------------
8279 -- Resolve_If_Expression --
8280 ---------------------------
8289 begin
8290 -- Defend against malformed expressions
8308 -- When the "then" expression is of a scalar subtype different from the
8309 -- result subtype, then insert a conversion to ensure the generation of
8310 -- a constraint check. The same is done for the else part below, again
8311 -- comparing subtypes rather than base types.
8318 -- If ELSE expression present, just resolve using the determined type
8319 -- If type is universal, resolve to any member of the class.
8328 else
8338 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8339 -- dynamically tagged must be known statically.
8344 then
8350 -- If no ELSE expression is present, root type must be Standard.Boolean
8351 -- and we provide a Standard.True result converted to the appropriate
8352 -- Boolean type (in case it is a derived boolean type).
8355 Else_Expr :=
8360 else
8374 -------------------------------
8375 -- Resolve_Indexed_Component --
8376 -------------------------------
8384 begin
8392 -- Use the context type to select the prefix that yields the correct
8393 -- component type.
8395 declare
8402 begin
8409 and then
8410 Covers
8413 then
8422 else
8428 else
8439 else
8446 -- If prefix is access type, dereference to get real array type.
8447 -- Note: we do not apply an access check because the expander always
8448 -- introduces an explicit dereference, and the check will happen there.
8454 -- If name was overloaded, set component type correctly now
8455 -- If a misplaced call to an entry family (which has no index types)
8456 -- return. Error will be diagnosed from calling context.
8460 else
8467 -- The prefix may have resolved to a string literal, in which case its
8468 -- etype has a special representation. This is only possible currently
8469 -- if the prefix is a static concatenation, written in functional
8470 -- notation.
8475 else
8482 else
8493 -- Do not generate the warning on suspicious index if we are analyzing
8494 -- package Ada.Tags; otherwise we will report the warning with the
8495 -- Prims_Ptr field of the dispatch table.
8498 or else not
8500 Ada_Tags)
8501 then
8506 -- If the array type is atomic, and the component is not atomic, then
8507 -- this is worth a warning, since we have a situation where the access
8508 -- to the component may cause extra read/writes of the atomic array
8509 -- object, or partial word accesses, which could be unexpected.
8515 and then Has_Atomic_Components
8518 then
8519 Error_Msg_N
8521 Error_Msg_N
8526 -----------------------------
8527 -- Resolve_Integer_Literal --
8528 -----------------------------
8531 begin
8536 --------------------------------
8537 -- Resolve_Intrinsic_Operator --
8538 --------------------------------
8547 -- If the operand is a literal, it cannot be the expression in a
8548 -- conversion. Use a qualified expression instead.
8550 ---------------------
8551 -- Convert_Operand --
8552 ---------------------
8558 begin
8560 Res :=
8566 else
8573 -- Start of processing for Resolve_Intrinsic_Operator
8575 begin
8576 -- We must preserve the original entity in a generic setting, so that
8577 -- the legality of the operation can be verified in an instance.
8592 -- If the result or operand types are private, rewrite with unchecked
8593 -- conversions on the operands and the result, to expose the proper
8594 -- underlying numeric type.
8599 then
8604 else
8625 then
8626 -- Add explicit conversion where needed, and save interpretations in
8627 -- case operands are overloaded.
8634 else
8640 else
8650 else
8655 --------------------------------------
8656 -- Resolve_Intrinsic_Unary_Operator --
8657 --------------------------------------
8659 procedure Resolve_Intrinsic_Unary_Operator
8662 is
8667 begin
8686 else
8691 ------------------------
8692 -- Resolve_Logical_Op --
8693 ------------------------
8698 begin
8701 -- Predefined operations on scalar types yield the base type. On the
8702 -- other hand, logical operations on arrays yield the type of the
8703 -- arguments (and the context).
8707 else
8711 -- The following test is required because the operands of the operation
8712 -- may be literals, in which case the resulting type appears to be
8713 -- compatible with a signed integer type, when in fact it is compatible
8714 -- only with modular types. If the context itself is universal, the
8715 -- operation is illegal.
8723 Error_Msg_N
8731 then
8735 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8736 -- is active and the result type is standard Boolean (do not mess with
8737 -- ops that return a nonstandard Boolean type, because something strange
8738 -- is going on).
8740 -- Note: you might expect this replacement to be done during expansion,
8741 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8742 -- is used, no part of the right operand of an "and" or "or" operator
8743 -- should be executed if the left operand would short-circuit the
8744 -- evaluation of the corresponding "and then" or "or else". If we left
8745 -- the replacement to expansion time, then run-time checks associated
8746 -- with such operands would be evaluated unconditionally, due to being
8747 -- before the condition prior to the rewriting as short-circuit forms
8748 -- during expansion.
8750 if Short_Circuit_And_Or
8753 then
8754 -- Mark the corresponding putative SCO operator as truly a logical
8755 -- (and short-circuit) operator.
8768 -- Case of OR changed to OR ELSE
8770 else
8778 -- Return now, since analysis of the rewritten ops will take care of
8779 -- other reference bookkeeping and expression folding.
8794 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8795 -- only when both operands have same static lower and higher bounds. Of
8796 -- course the types have to match, so only check if operands are
8797 -- compatible and the node itself has no errors.
8801 then
8802 declare
8806 begin
8807 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8808 -- operation if not needed.
8815 then
8816 Check_SPARK_05_Restriction
8823 ---------------------------
8824 -- Resolve_Membership_Op --
8825 ---------------------------
8827 -- The context can only be a boolean type, and does not determine the
8828 -- arguments. Arguments should be unambiguous, but the preference rule for
8829 -- universal types applies.
8839 -- Analysis has determined a unique type for the left operand. Use it to
8840 -- resolve the disjuncts.
8842 ----------------------------
8843 -- Resolve_Set_Membership --
8844 ----------------------------
8850 begin
8851 -- If the left operand is overloaded, find type compatible with not
8852 -- overloaded alternative of the right operand.
8861 else
8866 -- Unclear how to resolve expression if all alternatives are also
8867 -- overloaded.
8873 else
8882 -- Alternative is an expression, a range
8883 -- or a subtype mark.
8887 then
8894 -- Check for duplicates for discrete case
8897 declare
8906 begin
8907 -- Loop checking duplicates. This is quadratic, but giant sets
8908 -- are unlikely in this context so it's a reasonable choice.
8915 N_Character_Literal)
8917 then
8935 -- Start of processing for Resolve_Membership_Op
8937 begin
8943 Resolve_Set_Membership;
8947 and then
8949 or else
8952 then
8955 -- Ada 2005 (AI-251): Support the following case:
8957 -- type I is interface;
8958 -- type T is tagged ...
8960 -- function Test (O : I'Class) is
8961 -- begin
8962 -- return O in T'Class.
8963 -- end Test;
8965 -- In this case we have nothing else to do. The membership test will be
8966 -- done at run time.
8973 then
8975 else
8979 -- If mixed-mode operations are present and operands are all literal,
8980 -- the only interpretation involves Duration, which is probably not
8981 -- the intention of the programmer.
8996 then
9002 else
9007 -- Here after resolving membership operation
9014 ------------------
9015 -- Resolve_Null --
9016 ------------------
9021 begin
9022 -- Handle restriction against anonymous null access values This
9023 -- restriction can be turned off using -gnatdj.
9025 -- Ada 2005 (AI-231): Remove restriction
9028 and then not Debug_Flag_J
9031 then
9032 -- In the common case of a call which uses an explicitly null value
9033 -- for an access parameter, give specialized error message.
9036 Error_Msg_N
9039 -- Standard message for all other cases (are there any?)
9041 else
9042 Error_Msg_N
9047 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9048 -- assignment to a null-excluding object
9053 then
9055 Insert_Action
9060 else
9067 -- In a distributed context, null for a remote access to subprogram may
9068 -- need to be replaced with a special record aggregate. In this case,
9069 -- return after having done the transformation.
9074 then
9078 -- The null literal takes its type from the context
9083 -----------------------
9084 -- Resolve_Op_Concat --
9085 -----------------------
9089 -- We wish to avoid deep recursion, because concatenations are often
9090 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9091 -- operands nonrecursively until we find something that is not a simple
9092 -- concatenation (A in this case). We resolve that, and then walk back
9093 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9094 -- to do the rest of the work at each level. The Parent pointers allow
9095 -- us to avoid recursion, and thus avoid running out of memory. See also
9096 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9101 begin
9102 -- The following code is equivalent to:
9104 -- Resolve_Op_Concat_First (NN, Typ);
9105 -- Resolve_Op_Concat_Arg (N, ...);
9106 -- Resolve_Op_Concat_Rest (N, Typ);
9108 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9109 -- operand is a concatenation.
9111 -- Walk down left operands
9113 loop
9122 -- Now (given the above example) NN is A&B and Op1 is A
9124 -- First resolve Op1 ...
9128 -- ... then walk NN back up until we reach N (where we started), calling
9129 -- Resolve_Op_Concat_Rest along the way.
9131 loop
9138 Check_SPARK_05_Restriction
9143 ---------------------------
9144 -- Resolve_Op_Concat_Arg --
9145 ---------------------------
9147 procedure Resolve_Op_Concat_Arg
9152 is
9156 begin
9158 if Is_Comp
9162 then
9164 else
9168 -- If both Array & Array and Array & Component are visible, there is a
9169 -- potential ambiguity that must be reported.
9174 then
9178 -- If the operation is user-defined and not overloaded use its
9179 -- profile. The operation may be a renaming, in which case it has
9180 -- been rewritten, and we want the original profile.
9185 then
9187 Etype
9191 -- Otherwise an aggregate may match both the array type and the
9192 -- component type.
9194 else
9199 else
9203 then
9204 declare
9209 begin
9214 -- Special-case the error message when the overloading is
9215 -- caused by a function that yields an array and can be
9216 -- called without parameters.
9221 Error_Msg_NE
9223 Error_Msg_NE
9227 else
9235 or else
9237 then
9238 Error_Msg_N -- CODEFIX
9256 else
9261 else
9265 -- Concatenation is restricted in SPARK: each operand must be either a
9266 -- string literal, the name of a string constant, a static character or
9267 -- string expression, or another concatenation. Arg cannot be a
9268 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9269 -- separately on each final operand, past concatenation operations.
9273 Check_SPARK_05_Restriction
9281 then
9282 Check_SPARK_05_Restriction
9286 -- Do not issue error on an operand that is neither a character nor a
9287 -- string, as the error is issued in Resolve_Op_Concat.
9289 else
9296 -----------------------------
9297 -- Resolve_Op_Concat_First --
9298 -----------------------------
9305 begin
9306 -- The parser folds an enormous sequence of concatenations of string
9307 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9308 -- in the right operand. If the expression resolves to a predefined "&"
9309 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9310 -- we give an error. See P_Simple_Expression in Par.Ch4.
9315 then
9330 ----------------------------
9331 -- Resolve_Op_Concat_Rest --
9332 ----------------------------
9338 begin
9347 -- If this is not a static concatenation, but the result is a string
9348 -- type (and not an array of strings) ensure that static string operands
9349 -- have their subtypes properly constructed.
9353 then
9359 ----------------------
9360 -- Resolve_Op_Expon --
9361 ----------------------
9366 begin
9367 -- Catch attempts to do fixed-point exponentiation with universal
9368 -- operands, which is a case where the illegality is not caught during
9369 -- normal operator analysis. This is not done in preanalysis mode
9370 -- since the tree is not fully decorated during preanalysis.
9382 then
9392 then
9399 then
9403 -- We do the resolution using the base type, because intermediate values
9404 -- in expressions are always of the base type, not a subtype of it.
9409 -- For integer types, right argument must be in Natural range
9424 -- Evaluate the exponentiation operator for dimensioned type
9427 else
9431 -- Set overflow checking bit. Much cleverer code needed here eventually
9432 -- and perhaps the Resolve routines should be separated for the various
9433 -- arithmetic operations, since they will need different processing. ???
9442 --------------------
9443 -- Resolve_Op_Not --
9444 --------------------
9450 -- This function determines if the parent node is a boolean operator or
9451 -- operation (comparison op, membership test, or short circuit form) and
9452 -- the not in question is the left operand of this operation. Note that
9453 -- if the not is in parens, then false is returned.
9455 -----------------------
9456 -- Parent_Is_Boolean --
9457 -----------------------
9460 begin
9464 else
9466 when N_And_Then
9467 | N_In
9468 | N_Not_In
9469 | N_Op_And
9470 | N_Op_Eq
9471 | N_Op_Ge
9472 | N_Op_Gt
9473 | N_Op_Le
9474 | N_Op_Lt
9475 | N_Op_Ne
9476 | N_Op_Or
9477 | N_Op_Xor
9478 | N_Or_Else
9479 =>
9488 -- Start of processing for Resolve_Op_Not
9490 begin
9491 -- Predefined operations on scalar types yield the base type. On the
9492 -- other hand, logical operations on arrays yield the type of the
9493 -- arguments (and the context).
9497 else
9501 -- Straightforward case of incorrect arguments
9508 -- Special case of probable missing parens
9512 Error_Msg_N
9515 else
9516 Error_Msg_N
9523 -- OK resolution of NOT
9525 else
9526 -- Warn if non-boolean types involved. This is a case like not a < b
9527 -- where a and b are modular, where we will get (not a) < b and most
9528 -- likely not (a < b) was intended.
9530 if Warn_On_Questionable_Missing_Parens
9532 and then Parent_Is_Boolean
9533 then
9537 -- Warn on double negation if checking redundant constructs
9539 if Warn_On_Redundant_Constructs
9544 then
9548 -- Complete resolution and evaluation of NOT
9558 -----------------------------
9559 -- Resolve_Operator_Symbol --
9560 -----------------------------
9562 -- Nothing to be done, all resolved already
9568 begin
9572 ----------------------------------
9573 -- Resolve_Qualified_Expression --
9574 ----------------------------------
9582 begin
9585 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9586 -- operation if not needed.
9593 then
9594 Check_SPARK_05_Restriction
9598 -- A qualified expression requires an exact match of the type, class-
9599 -- wide matching is not allowed. However, if the qualifying type is
9600 -- specific and the expression has a class-wide type, it may still be
9601 -- okay, since it can be the result of the expansion of a call to a
9602 -- dispatching function, so we also have to check class-wideness of the
9603 -- type of the expression's original node.
9606 or else
9610 then
9614 -- If the target type is unconstrained, then we reset the type of the
9615 -- result from the type of the expression. For other cases, the actual
9616 -- subtype of the expression is the target type.
9620 then
9627 -- If we still have a qualified expression after the static evaluation,
9628 -- then apply a scalar range check if needed. The reason that we do this
9629 -- after the Eval call is that otherwise, the application of the range
9630 -- check may convert an illegal static expression and result in warning
9631 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9637 -- Finally, check whether a predicate applies to the target type. This
9638 -- comes from AI12-0100. As for type conversions, check the enclosing
9639 -- context to prevent an infinite expansion.
9645 or else
9647 then
9650 -- In the case of a qualified expression in an allocator, the check
9651 -- is applied when expanding the allocator, so avoid redundant check.
9655 then
9661 ------------------------------
9662 -- Resolve_Raise_Expression --
9663 ------------------------------
9666 begin
9670 else
9675 -------------------
9676 -- Resolve_Range --
9677 -------------------
9684 -- Returns True if N is of the form X'First .. X'Last where X is the
9685 -- same entity for both attributes.
9687 --------------------
9688 -- First_Last_Ref --
9689 --------------------
9695 begin
9700 then
9701 declare
9704 begin
9708 then
9717 -- Start of processing for Resolve_Range
9719 begin
9722 -- The lower bound should be in Typ. The higher bound can be in Typ's
9723 -- base type if the range is null. It may still be invalid if it is
9724 -- higher than the lower bound. This is checked later in the context in
9725 -- which the range appears.
9730 -- Check for inappropriate range on unordered enumeration type
9734 -- Exclude X'First .. X'Last if X is the same entity for both
9736 and then not First_Last_Ref
9737 then
9739 Error_Msg_NE
9746 -- We have to check the bounds for being within the base range as
9747 -- required for a non-static context. Normally this is automatic and
9748 -- done as part of evaluating expressions, but the N_Range node is an
9749 -- exception, since in GNAT we consider this node to be a subexpression,
9750 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9751 -- this, but that would put the test on the main evaluation path for
9752 -- expressions.
9757 -- Check for an ambiguous range over character literals. This will
9758 -- happen with a membership test involving only literals.
9766 -- If bounds are static, constant-fold them, so size computations are
9767 -- identical between front-end and back-end. Do not perform this
9768 -- transformation while analyzing generic units, as type information
9769 -- would be lost when reanalyzing the constant node in the instance.
9782 --------------------------
9783 -- Resolve_Real_Literal --
9784 --------------------------
9789 begin
9790 -- Special processing for fixed-point literals to make sure that the
9791 -- value is an exact multiple of small where this is required. We skip
9792 -- this for the universal real case, and also for generic types.
9798 then
9799 declare
9806 begin
9807 -- Case of literal is not an exact multiple of the Small
9811 -- For a source program literal for a decimal fixed-point type,
9812 -- this is statically illegal (RM 4.9(36)).
9817 then
9821 -- Generate a warning if literal from source
9824 and then Warn_On_Bad_Fixed_Value
9825 then
9826 Error_Msg_N
9828 N);
9831 -- Replace literal by a value that is the exact representation
9832 -- of a value of the type, i.e. a multiple of the small value,
9833 -- by truncation, since Machine_Rounds is false for all GNAT
9834 -- fixed-point types (RM 4.9(38)).
9844 -- In all cases, set the corresponding integer field
9850 -- Now replace the actual type by the expected type as usual
9856 -----------------------
9857 -- Resolve_Reference --
9858 -----------------------
9863 begin
9864 -- Replace general access with specific type
9872 -- If we are taking the reference of a volatile entity, then treat it as
9873 -- a potential modification of this entity. This is too conservative,
9874 -- but necessary because remove side effects can cause transformations
9875 -- of normal assignments into reference sequences that otherwise fail to
9876 -- notice the modification.
9883 --------------------------------
9884 -- Resolve_Selected_Component --
9885 --------------------------------
9900 -- Check whether this is the initialization of a component within an
9901 -- init proc (by assignment or call to another init proc). If true,
9902 -- there is no need for a discriminant check.
9904 --------------------
9905 -- Init_Component --
9906 --------------------
9909 begin
9910 return Inside_Init_Proc
9916 -- Start of processing for Resolve_Selected_Component
9918 begin
9921 -- Use the context type to select the prefix that has a selector
9922 -- of the correct name and type.
9930 else
9934 -- Locate selected component. For a private prefix the selector
9935 -- can denote a discriminant.
9939 -- The visible components of a class-wide type are those of
9940 -- the root type.
9950 then
9957 else
9961 Error_Msg_N
9966 else
9969 -- There may be an implicit dereference. Retrieve
9970 -- designated record type.
9974 else
9980 -- Resolution chooses the new interpretation.
9981 -- Find the component with the right name.
9986 loop
10003 -- There must be a legal interpretation at this point
10010 else
10011 -- Resolve prefix with its type
10016 -- Generate cross-reference. We needed to wait until full overloading
10017 -- resolution was complete to do this, since otherwise we can't tell if
10018 -- we are an lvalue or not.
10022 else
10026 -- If prefix is an access type, the node will be transformed into an
10027 -- explicit dereference during expansion. The type of the node is the
10028 -- designated type of that of the prefix.
10033 else
10037 -- Set flag for expander if discriminant check required on a component
10038 -- appearing within a variant.
10044 and then
10047 and then not Init_Component
10048 then
10056 -- If the prefix is a record conversion, this may be a renamed
10057 -- discriminant whose bounds differ from those of the original
10058 -- one, so we must ensure that a range check is performed.
10063 then
10067 -- Note: No Eval processing is required, because the prefix is of a
10068 -- record type, or protected type, and neither can possibly be static.
10070 -- If the record type is atomic, and the component is non-atomic, then
10071 -- this is worth a warning, since we have a situation where the access
10072 -- to the component may cause extra read/writes of the atomic array
10073 -- object, or partial word accesses, both of which may be unexpected.
10079 then
10080 Error_Msg_N
10083 Error_Msg_N
10091 -------------------
10092 -- Resolve_Shift --
10093 -------------------
10100 begin
10101 -- We do the resolution using the base type, because intermediate values
10102 -- in expressions always are of the base type, not a subtype of it.
10115 ---------------------------
10116 -- Resolve_Short_Circuit --
10117 ---------------------------
10124 begin
10125 -- Ensure all actions associated with the left operand (e.g.
10126 -- finalization of transient objects) are fully evaluated locally within
10127 -- an expression with actions. This is particularly helpful for coverage
10128 -- analysis. However this should not happen in generics or if option
10129 -- Minimize_Expression_With_Actions is set.
10132 declare
10134 begin
10142 -- Set Comes_From_Source on L to preserve warnings for unset
10143 -- reference.
10152 -- Check for issuing warning for always False assert/check, this happens
10153 -- when assertions are turned off, in which case the pragma Assert/Check
10154 -- was transformed into:
10156 -- if False and then <condition> then ...
10158 -- and we detect this pattern
10160 if Warn_On_Assertion_Failure
10167 then
10168 declare
10171 begin
10172 -- Special handling of Asssert pragma
10176 then
10177 declare
10179 Original_Node
10180 (Expression
10183 begin
10184 -- Don't warn if original condition is explicit False,
10185 -- since obviously the failure is expected in this case.
10189 then
10192 -- Issue warning. We do not want the deletion of the
10193 -- IF/AND-THEN to take this message with it. We achieve this
10194 -- by making sure that the expanded code points to the Sloc
10195 -- of the expression, not the original pragma.
10197 else
10198 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10199 -- The source location of the expression is not usually
10200 -- the best choice here. For example, it gets located on
10201 -- the last AND keyword in a chain of boolean expressiond
10202 -- AND'ed together. It is best to put the message on the
10203 -- first character of the assertion, which is the effect
10204 -- of the First_Node call here.
10206 Error_Msg_F
10208 Expression
10213 -- Similar processing for Check pragma
10217 then
10218 -- Don't want to warn if original condition is explicit False
10220 declare
10222 Original_Node
10223 (Expression
10225 begin
10228 then
10231 -- Post warning
10233 else
10234 -- Again use Error_Msg_F rather than Error_Msg_N, see
10235 -- comment above for an explanation of why we do this.
10237 Error_Msg_F
10239 Expression
10247 -- Continue with processing of short circuit
10256 -------------------
10257 -- Resolve_Slice --
10258 -------------------
10267 begin
10270 -- Use the context type to select the prefix that yields the correct
10271 -- array type.
10273 declare
10280 begin
10288 then
10296 else
10301 else
10312 else
10322 -- If the prefix is an access to an unconstrained array, we must use
10323 -- the actual subtype of the object to perform the index checks. The
10324 -- object denoted by the prefix is implicit in the node, so we build
10325 -- an explicit representation for it in order to compute the actual
10326 -- subtype.
10331 declare
10335 begin
10346 then
10349 -- If the name is a selected component that depends on discriminants,
10350 -- build an actual subtype for it. This can happen only when the name
10351 -- itself is overloaded; otherwise the actual subtype is created when
10352 -- the selected component is analyzed.
10355 and then Full_Analysis
10357 then
10358 declare
10361 begin
10366 -- Maybe this should just be "else", instead of checking for the
10367 -- specific case of slice??? This is needed for the case where the
10368 -- prefix is an Image attribute, which gets expanded to a slice, and so
10369 -- has a constrained subtype which we want to use for the slice range
10370 -- check applied below (the range check won't get done if the
10371 -- unconstrained subtype of the 'Image is used).
10377 -- Obtain the type of the array index
10381 else
10385 -- If name was overloaded, set slice type correctly now
10389 -- Handle the generation of a range check that compares the array index
10390 -- against the discrete_range. The check is not applied to internally
10391 -- built nodes associated with the expansion of dispatch tables. Check
10392 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10393 -- the unit.
10395 if Tagged_Type_Expansion
10401 then
10404 -- The discrete_range is specified by a subtype indication. Create a
10405 -- shallow copy and inherit the type, parent and source location from
10406 -- the discrete_range. This ensures that the range check is inserted
10407 -- relative to the slice and that the runtime exception points to the
10408 -- proper construct.
10417 -- The discrete_range is a regular range. Resolve the bounds and remove
10418 -- their side effects.
10420 else
10437 -- Check bad use of type with predicates
10439 declare
10442 begin
10445 then
10447 else
10452 Bad_Predicated_Subtype_Use
10457 -- Otherwise here is where we check suspicious indexes
10468 ----------------------------
10469 -- Resolve_String_Literal --
10470 ----------------------------
10481 begin
10482 -- For a string appearing in a concatenation, defer creation of the
10483 -- string_literal_subtype until the end of the resolution of the
10484 -- concatenation, because the literal may be constant-folded away. This
10485 -- is a useful optimization for long concatenation expressions.
10487 -- If the string is an aggregate built for a single character (which
10488 -- happens in a non-static context) or a is null string to which special
10489 -- checks may apply, we build the subtype. Wide strings must also get a
10490 -- string subtype if they come from a one character aggregate. Strings
10491 -- generated by attributes might be static, but it is often hard to
10492 -- determine whether the enclosing context is static, so we generate
10493 -- subtypes for them as well, thus losing some rarer optimizations ???
10494 -- Same for strings that come from a static conversion.
10496 Need_Check :=
10505 -- If the resolving type is itself a string literal subtype, we can just
10506 -- reuse it, since there is no point in creating another.
10512 and then not Need_Check
10514 N_Attribute_Reference,
10515 N_Qualified_Expression,
10516 N_Type_Conversion)
10517 then
10520 -- Do not generate a string literal subtype for the default expression
10521 -- of a formal parameter in GNATprove mode. This is because the string
10522 -- subtype is associated with the freezing actions of the subprogram,
10523 -- however freezing is disabled in GNATprove mode and as a result the
10524 -- subtype is unavailable.
10526 elsif GNATprove_Mode
10528 then
10531 -- Otherwise we must create a string literal subtype. Note that the
10532 -- whole idea of string literal subtypes is simply to avoid the need
10533 -- for building a full fledged array subtype for each literal.
10535 else
10541 or else Need_Check
10542 then
10549 then
10555 -- The validity of a null string has been checked in the call to
10556 -- Eval_String_Literal.
10561 -- Always accept string literal with component type Any_Character, which
10562 -- occurs in error situations and in comparisons of literals, both of
10563 -- which should accept all literals.
10568 -- If the type is bit-packed, then we always transform the string
10569 -- literal into a full fledged aggregate.
10574 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10576 else
10577 -- For Standard.Wide_Wide_String, or any other type whose component
10578 -- type is Standard.Wide_Wide_Character, we know that all the
10579 -- characters in the string must be acceptable, since the parser
10580 -- accepted the characters as valid character literals.
10585 -- For the case of Standard.String, or any other type whose component
10586 -- type is Standard.Character, we must make sure that there are no
10587 -- wide characters in the string, i.e. that it is entirely composed
10588 -- of characters in range of type Character.
10590 -- If the string literal is the result of a static concatenation, the
10591 -- test has already been performed on the components, and need not be
10592 -- repeated.
10596 then
10600 -- If we are out of range, post error. This is one of the
10601 -- very few places that we place the flag in the middle of
10602 -- a token, right under the offending wide character. Not
10603 -- quite clear if this is right wrt wide character encoding
10604 -- sequences, but it's only an error message.
10606 Error_Msg
10613 -- For the case of Standard.Wide_String, or any other type whose
10614 -- component type is Standard.Wide_Character, we must make sure that
10615 -- there are no wide characters in the string, i.e. that it is
10616 -- entirely composed of characters in range of type Wide_Character.
10618 -- If the string literal is the result of a static concatenation,
10619 -- the test has already been performed on the components, and need
10620 -- not be repeated.
10624 then
10628 -- If we are out of range, post error. This is one of the
10629 -- very few places that we place the flag in the middle of
10630 -- a token, right under the offending wide character.
10632 -- This is not quite right, because characters in general
10633 -- will take more than one character position ???
10635 Error_Msg
10642 -- If the root type is not a standard character, then we will convert
10643 -- the string into an aggregate and will let the aggregate code do
10644 -- the checking. Standard Wide_Wide_Character is also OK here.
10646 else
10650 -- See if the component type of the array corresponding to the string
10651 -- has compile time known bounds. If yes we can directly check
10652 -- whether the evaluation of the string will raise constraint error.
10653 -- Otherwise we need to transform the string literal into the
10654 -- corresponding character aggregate and let the aggregate code do
10655 -- the checking.
10659 -- Check for the case of full range, where we are definitely OK
10665 -- Here the range is not the complete base type range, so check
10667 declare
10675 begin
10678 then
10684 then
10685 Apply_Compile_Time_Constraint_Error
10687 CE_Range_Check_Failed,
10698 -- If we got here we meed to transform the string literal into the
10699 -- equivalent qualified positional array aggregate. This is rather
10700 -- heavy artillery for this situation, but it is hard work to avoid.
10702 declare
10707 begin
10708 -- Build the character literals, we give them source locations that
10709 -- correspond to the string positions, which is a bit tricky given
10710 -- the possible presence of wide character escape sequences.
10724 -- Should we have a call to Skip_Wide here ???
10726 -- ??? else
10727 -- Skip_Wide (P);
10735 Expression =>
10742 -------------------------
10743 -- Resolve_Target_Name --
10744 -------------------------
10747 begin
10751 -----------------------------
10752 -- Resolve_Type_Conversion --
10753 -----------------------------
10765 -- Set to False to suppress cases where we want to suppress the test
10766 -- for redundancy to avoid possible false positives on this warning.
10768 begin
10769 if not Conv_OK
10771 then
10775 -- If the Operand Etype is Universal_Fixed, then the conversion is
10776 -- never redundant. We need this check because by the time we have
10777 -- finished the rather complex transformation, the conversion looks
10778 -- redundant when it is not.
10783 -- If the operand is marked as Any_Fixed, then special processing is
10784 -- required. This is also a case where we suppress the test for a
10785 -- redundant conversion, since most certainly it is not redundant.
10790 -- Mixed-mode operation involving a literal. Context must be a fixed
10791 -- type which is applied to the literal subsequently.
10793 -- Multiplication and division involving two fixed type operands must
10794 -- yield a universal real because the result is computed in arbitrary
10795 -- precision.
10801 then
10807 or else
10809 then
10810 -- Return if expression is ambiguous
10815 -- If nothing else, the available fixed type is Duration
10817 else
10821 -- Resolve the real operand with largest available precision
10825 else
10831 -- If the operand is a literal (it could be a non-static and
10832 -- illegal exponentiation) check whether the use of Duration
10833 -- is potentially inaccurate.
10838 then
10839 Error_Msg_N
10842 Error_Msg_N
10849 then
10852 else
10861 -- In SPARK, a type conversion between array types should be restricted
10862 -- to types which have matching static bounds.
10864 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10865 -- operation if not needed.
10872 then
10873 Check_SPARK_05_Restriction
10877 -- In formal mode, the operand of an ancestor type conversion must be an
10878 -- object (not an expression).
10886 then
10892 -- Note: we do the Eval_Type_Conversion call before applying the
10893 -- required checks for a subtype conversion. This is important, since
10894 -- both are prepared under certain circumstances to change the type
10895 -- conversion to a constraint error node, but in the case of
10896 -- Eval_Type_Conversion this may reflect an illegality in the static
10897 -- case, and we would miss the illegality (getting only a warning
10898 -- message), if we applied the type conversion checks first.
10902 -- Even when evaluation is not possible, we may be able to simplify the
10903 -- conversion or its expression. This needs to be done before applying
10904 -- checks, since otherwise the checks may use the original expression
10905 -- and defeat the simplifications. This is specifically the case for
10906 -- elimination of the floating-point Truncation attribute in
10907 -- float-to-int conversions.
10911 -- If after evaluation we still have a type conversion, then we may need
10912 -- to apply checks required for a subtype conversion.
10914 -- Skip these type conversion checks if universal fixed operands
10915 -- operands involved, since range checks are handled separately for
10916 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10922 then
10926 -- Issue warning for conversion of simple object to its own type. We
10927 -- have to test the original nodes, since they may have been rewritten
10928 -- by various optimizations.
10932 -- Here we test for a redundant conversion if the warning mode is
10933 -- active (and was not locally reset), and we have a type conversion
10934 -- from source not appearing in a generic instance.
10936 if Test_Redundant
10939 and then not In_Instance
10940 then
10944 -- If the node is part of a larger expression, the Target_Type
10945 -- may not be the original type of the node if the context is a
10946 -- condition. Recover original type to see if conversion is needed.
10950 then
10954 -- If we have an entity name, then give the warning if the entity
10955 -- is the right type, or if it is a loop parameter covered by the
10956 -- original type (that's needed because loop parameters have an
10957 -- odd subtype coming from the bounds).
10960 and then
10962 or else
10966 -- If not an entity, then type of expression must match
10969 then
10970 -- One more check, do not give warning if the analyzed conversion
10971 -- has an expression with non-static bounds, and the bounds of the
10972 -- target are static. This avoids junk warnings in cases where the
10973 -- conversion is necessary to establish staticness, for example in
10974 -- a case statement.
10978 then
10981 -- Finally, if this type conversion occurs in a context requiring
10982 -- a prefix, and the expression is a qualified expression then the
10983 -- type conversion is not redundant, since a qualified expression
10984 -- is not a prefix, whereas a type conversion is. For example, "X
10985 -- := T'(Funx(...)).Y;" is illegal because a selected component
10986 -- requires a prefix, but a type conversion makes it legal: "X :=
10987 -- T(T'(Funx(...))).Y;"
10989 -- In Ada 2012, a qualified expression is a name, so this idiom is
10990 -- no longer needed, but we still suppress the warning because it
10991 -- seems unfriendly for warnings to pop up when you switch to the
10992 -- newer language version.
10996 N_Indexed_Component,
10997 N_Selected_Component,
10998 N_Slice,
10999 N_Explicit_Dereference)
11000 then
11003 -- Never warn on conversion to Long_Long_Integer'Base since
11004 -- that is most likely an artifact of the extended overflow
11005 -- checking and comes from complex expanded code.
11010 -- Here we give the redundant conversion warning. If it is an
11011 -- entity, give the name of the entity in the message. If not,
11012 -- just mention the expression.
11014 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11016 else
11019 Error_Msg_NE -- CODEFIX
11022 else
11023 Error_Msg_NE
11031 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11032 -- No need to perform any interface conversion if the type of the
11033 -- expression coincides with the target type.
11036 and then Expander_Active
11038 then
11039 declare
11043 begin
11044 -- If the type of the operand is a limited view, use nonlimited
11045 -- view when available. If it is a class-wide type, recover the
11046 -- class-wide type of the nonlimited view.
11050 then
11066 -- Conversion from interface type
11070 -- Ada 2005 (AI-217): Handle entities from limited views
11074 Error_Msg_NE -- CODEFIX
11077 Error_Msg_N
11079 N);
11082 and then not
11085 then
11087 Error_Msg_NE -- CODEFIX
11090 Error_Msg_N
11092 N);
11094 else
11098 -- Conversion to interface type
11102 -- Handle subtypes
11109 or else Interface_Present_In_Ancestor
11112 then
11114 else
11117 Error_Msg_N
11125 -- Ada 2012: once the type conversion is resolved, check whether the
11126 -- operand statisfies the static predicate of the target type.
11132 -- If at this stage we have a real to integer conversion, make sure that
11133 -- the Do_Range_Check flag is set, because such conversions in general
11134 -- need a range check. We only need this if expansion is off.
11135 -- In GNATprove mode, we only do that when converting from fixed-point
11136 -- (as floating-point to integer conversions are now handled in
11137 -- GNATprove mode).
11140 and then not Expander_Active
11145 then
11149 -- Generating C code a type conversion of an access to constrained
11150 -- array type to access to unconstrained array type involves building
11151 -- a fat pointer which in general cannot be generated on the fly. We
11152 -- remove side effects in order to store the result of the conversion
11153 -- into a temporary.
11155 if Modify_Tree_For_C
11162 then
11167 ----------------------
11168 -- Resolve_Unary_Op --
11169 ----------------------
11178 begin
11181 Check_SPARK_05_Restriction
11185 -- Deal with intrinsic unary operators
11191 then
11196 -- Deal with universal cases
11199 or else
11201 then
11208 -- Generate warning for expressions like abs (x mod 2)
11210 if Warn_On_Redundant_Constructs
11212 then
11216 Error_Msg_N -- CODEFIX
11221 -- Deal with reference generation
11228 -- Set overflow checking bit. Much cleverer code needed here eventually
11229 -- and perhaps the Resolve routines should be separated for the various
11230 -- arithmetic operations, since they will need different processing ???
11238 -- Generate warning for expressions like -5 mod 3 for integers. No need
11239 -- to worry in the floating-point case, since parens do not affect the
11240 -- result so there is no point in giving in a warning.
11242 declare
11251 begin
11252 if Warn_On_Questionable_Missing_Parens
11256 then
11259 -- We are looking for cases where the right operand is not
11260 -- parenthesized, and is a binary operator, multiply, divide, or
11261 -- mod. These are the cases where the grouping can affect results.
11265 then
11266 -- For mod, we always give the warning, since the value is
11267 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11268 -- -(5 mod 315)). But for the other cases, the only concern is
11269 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11270 -- overflows, but (-2) * 64 does not). So we try to give the
11271 -- message only when overflow is possible.
11275 then
11280 else
11286 else
11290 -- Note that the test below is deliberately excluding the
11291 -- largest negative number, since that is a potentially
11292 -- troublesome case (e.g. -2 * x, where the result is the
11293 -- largest negative integer has an overflow with 2 * x).
11300 -- For the multiplication case, the only case we have to worry
11301 -- about is when (-a)*b is exactly the largest negative number
11302 -- so that -(a*b) can cause overflow. This can only happen if
11303 -- a is a power of 2, and more generally if any operand is a
11304 -- constant that is not a power of 2, then the parentheses
11305 -- cannot affect whether overflow occurs. We only bother to
11306 -- test the left most operand
11308 -- Loop looking at left operands for one that has known value
11315 -- Operand value of 0 or 1 skips warning
11320 -- Otherwise check power of 2, if power of 2, warn, if
11321 -- anything else, skip warning.
11323 else
11327 else
11336 -- Keep looking at left operands
11341 -- For rem or "/" we can only have a problematic situation
11342 -- if the divisor has a value of minus one or one. Otherwise
11343 -- overflow is impossible (divisor > 1) or we have a case of
11344 -- division by zero in any case.
11349 then
11353 -- If we fall through warning should be issued
11355 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11357 Error_Msg_N
11364 ----------------------------------
11365 -- Resolve_Unchecked_Expression --
11366 ----------------------------------
11368 procedure Resolve_Unchecked_Expression
11371 is
11372 begin
11377 ---------------------------------------
11378 -- Resolve_Unchecked_Type_Conversion --
11379 ---------------------------------------
11381 procedure Resolve_Unchecked_Type_Conversion
11384 is
11390 begin
11391 -- Resolve operand using its own type
11395 -- In an inlined context, the unchecked conversion may be applied
11396 -- to a literal, in which case its type is the type of the context.
11397 -- (In other contexts conversions cannot apply to literals).
11399 if In_Inlined_Body
11403 then
11411 ------------------------------
11412 -- Rewrite_Operator_As_Call --
11413 ------------------------------
11420 begin
11427 New_N :=
11438 ------------------------------
11439 -- Rewrite_Renamed_Operator --
11440 ------------------------------
11442 procedure Rewrite_Renamed_Operator
11446 is
11451 begin
11452 -- Do not perform this transformation within a pre/postcondition,
11453 -- because the expression will be reanalyzed, and the transformation
11454 -- might affect the visibility of the operator, e.g. in an instance.
11455 -- Note that fully analyzed and expanded pre/postconditions appear as
11456 -- pragma Check equivalents.
11462 -- Likewise when an expression function is being preanalyzed, since the
11463 -- expression will be reanalyzed as part of the generated body.
11466 declare
11468 begin
11471 = N_Expression_Function
11472 then
11478 -- Rewrite the operator node using the real operator, not its renaming.
11479 -- Exclude user-defined intrinsic operations of the same name, which are
11480 -- treated separately and rewritten as calls.
11489 -- Indicate that both the original entity and its renaming are
11490 -- referenced at this point.
11501 -- If the context type is private, add the appropriate conversions so
11502 -- that the operator is applied to the full view. This is done in the
11503 -- routines that resolve intrinsic operators.
11507 when N_Op_Add
11508 | N_Op_Divide
11509 | N_Op_Expon
11510 | N_Op_Mod
11511 | N_Op_Multiply
11512 | N_Op_Rem
11513 | N_Op_Subtract
11514 =>
11517 when N_Op_Abs
11518 | N_Op_Minus
11519 | N_Op_Plus
11520 =>
11530 -- Operator renames a user-defined operator of the same name. Use the
11531 -- original operator in the node, which is the one Gigi knows about.
11538 -----------------------
11539 -- Set_Slice_Subtype --
11540 -----------------------
11542 -- Build an implicit subtype declaration to represent the type delivered by
11543 -- the slice. This is an abbreviated version of an array subtype. We define
11544 -- an index subtype for the slice, using either the subtype name or the
11545 -- discrete range of the slice. To be consistent with index usage elsewhere
11546 -- we create a list header to hold the single index. This list is not
11547 -- otherwise attached to the syntax tree.
11558 begin
11564 else
11565 -- We force the evaluation of a range. This is definitely needed in
11566 -- the renamed case, and seems safer to do unconditionally. Note in
11567 -- any case that since we will create and insert an Itype referring
11568 -- to this range, we must make sure any side effect removal actions
11569 -- are inserted before the Itype definition.
11575 -- If the discrete range is given by a subtype indication, the
11576 -- type of the slice is the base of the subtype mark.
11579 declare
11581 begin
11590 -- Take a new copy of Drange (where bounds have been rewritten to
11591 -- reference side-effect-free names). Using a separate tree ensures
11592 -- that further expansion (e.g. while rewriting a slice assignment
11593 -- into a FOR loop) does not attempt to remove side effects on the
11594 -- bounds again (which would cause the bounds in the index subtype
11595 -- definition to refer to temporaries before they are defined) (the
11596 -- reason is that some names are considered side effect free here
11597 -- for the subtype, but not in the context of a loop iteration
11598 -- scheme).
11619 -- The Etype of the existing Slice node is reset to this slice subtype.
11620 -- Its bounds are obtained from its first index.
11624 -- For bit-packed slice subtypes, freeze immediately (except in the case
11625 -- of being in a "spec expression" where we never freeze when we first
11626 -- see the expression).
11631 -- For all other cases insert an itype reference in the slice's actions
11632 -- so that the itype is frozen at the proper place in the tree (i.e. at
11633 -- the point where actions for the slice are analyzed). Note that this
11634 -- is different from freezing the itype immediately, which might be
11635 -- premature (e.g. if the slice is within a transient scope). This needs
11636 -- to be done only if expansion is enabled.
11643 --------------------------------
11644 -- Set_String_Literal_Subtype --
11645 --------------------------------
11653 begin
11665 -- The low bound is set from the low bound of the corresponding index
11666 -- type. Note that we do not store the high bound in the string literal
11667 -- subtype, but it can be deduced if necessary from the length and the
11668 -- low bound.
11673 -- If the lower bound is not static we create a range for the string
11674 -- literal, using the index type and the known length of the literal.
11675 -- The index type is not necessarily Positive, so the upper bound is
11676 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11678 else
11679 declare
11685 Prefix =>
11689 Left_Opnd =>
11692 Prefix =>
11694 Expressions =>
11696 Right_Opnd =>
11705 begin
11707 Set_String_Literal_Low_Bound
11710 else
11711 -- If the index type is an enumeration type, build bounds
11712 -- expression with attributes.
11714 Set_String_Literal_Low_Bound
11718 Prefix =>
11725 -- Build bona fide subtype for the string, and wrap it in an
11726 -- unchecked conversion, because the backend expects the
11727 -- String_Literal_Subtype to have a static lower bound.
11729 Index_Subtype :=
11736 -- In the context, the Index_Type may already have a constraint,
11737 -- so use common base type on string subtype. The base type may
11738 -- be used when generating attributes of the string, for example
11739 -- in the context of a slice assignment.
11764 ------------------------------
11765 -- Simplify_Type_Conversion --
11766 ------------------------------
11769 begin
11771 declare
11776 begin
11777 -- Special processing if the conversion is the expression of a
11778 -- Rounding or Truncation attribute reference. In this case we
11779 -- replace:
11781 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11783 -- by
11785 -- ityp (x)
11787 -- with the Float_Truncate flag set to False or True respectively,
11788 -- which is more efficient.
11791 and then
11797 Name_Truncation)
11798 then
11799 declare
11802 begin
11812 -----------------------------
11813 -- Unique_Fixed_Point_Type --
11814 -----------------------------
11818 -- Give error messages for true ambiguity. Messages are posted on node
11819 -- N, and entities T1, T2 are the possible interpretations.
11821 -----------------------
11822 -- Fixed_Point_Error --
11823 -----------------------
11826 begin
11832 -- Local variables
11840 -- Start of processing for Unique_Fixed_Point_Type
11842 begin
11843 -- The operations on Duration are visible, so Duration is always a
11844 -- possible interpretation.
11848 -- Look for fixed-point types in enclosing scopes
11857 then
11861 else
11872 -- Look for visible fixed type declarations in the context
11883 then
11887 else
11902 else
11903 -- When the context is a type conversion, issue the warning on the
11904 -- expression of the conversion because it is the actual operation.
11908 else
11912 Error_Msg_NE
11919 ----------------------
11920 -- Valid_Conversion --
11921 ----------------------
11923 function Valid_Conversion
11928 is
11933 function Conversion_Check
11936 -- Little routine to post Msg if Valid is False, returns Valid value
11939 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11941 procedure Conversion_Error_NE
11945 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11948 -- Return True if expression is within an instance but is not in one of
11949 -- the actuals of the instantiation. Type conversions within an instance
11950 -- are not rechecked because type visbility may lead to spurious errors,
11951 -- but conversions in an actual for a formal object must be checked.
11953 function Valid_Tagged_Conversion
11956 -- Specifically test for validity of tagged conversions
11959 -- Check index and component conformance, and accessibility levels if
11960 -- the component types are anonymous access types (Ada 2005).
11962 ----------------------
11963 -- Conversion_Check --
11964 ----------------------
11966 function Conversion_Check
11969 is
11970 begin
11971 if not Valid
11973 -- A generic unit has already been analyzed and we have verified
11974 -- that a particular conversion is OK in that context. Since the
11975 -- instance is reanalyzed without relying on the relationships
11976 -- established during the analysis of the generic, it is possible
11977 -- to end up with inconsistent views of private types. Do not emit
11978 -- the error message in such cases. The rest of the machinery in
11979 -- Valid_Conversion still ensures the proper compatibility of
11980 -- target and operand types.
11982 and then not In_Instance_Code
11983 then
11990 ------------------------
11991 -- Conversion_Error_N --
11992 ------------------------
11995 begin
12001 -------------------------
12002 -- Conversion_Error_NE --
12003 -------------------------
12005 procedure Conversion_Error_NE
12009 is
12010 begin
12016 ----------------------
12017 -- In_Instance_Code --
12018 ----------------------
12023 begin
12027 else
12031 -- The expression is part of an actual object if it appears in
12032 -- the generated object declaration in the instance.
12036 then
12039 else
12040 exit when
12049 -- Otherwise the expression appears within the instantiated unit
12055 ----------------------------
12056 -- Valid_Array_Conversion --
12057 ----------------------------
12074 begin
12075 -- Error if wrong number of dimensions
12077 if
12079 then
12080 Conversion_Error_N
12084 -- Number of dimensions matches
12086 else
12087 -- Loop through indexes of the two arrays
12095 -- Error if index types are incompatible
12101 then
12102 Conversion_Error_N
12104 Operand);
12112 -- If component types have same base type, all set
12117 -- Here if base types of components are not the same. The only
12118 -- time this is allowed is if we have anonymous access types.
12120 -- The conversion of arrays of anonymous access types can lead
12121 -- to dangling pointers. AI-392 formalizes the accessibility
12122 -- checks that must be applied to such conversions to prevent
12123 -- out-of-scope references.
12125 elsif Ekind_In
12127 E_Anonymous_Access_Subprogram_Type)
12129 and then
12131 then
12134 then
12137 Conversion_Error_N
12147 -- Conversion not allowed because of accessibility levels
12149 else
12150 Conversion_Error_N
12156 else
12160 -- All other cases where component base types do not match
12162 else
12163 Conversion_Error_N
12165 Operand);
12169 -- Check that component subtypes statically match. For numeric
12170 -- types this means that both must be either constrained or
12171 -- unconstrained. For enumeration types the bounds must match.
12172 -- All of this is checked in Subtypes_Statically_Match.
12174 if not Subtypes_Statically_Match
12176 then
12177 Conversion_Error_N
12186 -----------------------------
12187 -- Valid_Tagged_Conversion --
12188 -----------------------------
12190 function Valid_Tagged_Conversion
12193 is
12194 begin
12195 -- Upward conversions are allowed (RM 4.6(22))
12199 then
12202 -- Downward conversion are allowed if the operand is class-wide
12203 -- (RM 4.6(23)).
12207 then
12212 then
12213 return
12217 -- Ada 2005 (AI-251): The conversion to/from interface types is
12218 -- always valid. The types involved may be class-wide (sub)types.
12222 then
12225 -- If the operand is a class-wide type obtained through a limited_
12226 -- with clause, and the context includes the nonlimited view, use
12227 -- it to determine whether the conversion is legal.
12233 then
12238 then
12241 else
12242 Conversion_Error_NE
12249 -- Start of processing for Valid_Conversion
12251 begin
12255 declare
12263 begin
12264 -- Remove procedure calls, which syntactically cannot appear in
12265 -- this context, but which cannot be removed by type checking,
12266 -- because the context does not impose a type.
12268 -- The node may be labelled overloaded, but still contain only one
12269 -- interpretation because others were discarded earlier. If this
12270 -- is the case, retain the single interpretation if legal.
12278 then
12279 -- More than one candidate interpretation is available
12287 -- When compiling for a system where Address is of a visible
12288 -- integer type, spurious ambiguities can be produced when
12289 -- arithmetic operations have a literal operand and return
12290 -- System.Address or a descendant of it. These ambiguities
12291 -- are usually resolved by the context, but for conversions
12292 -- there is no context type and the removal of the spurious
12293 -- operations must be done explicitly here.
12295 if not Address_Is_Private
12297 then
12322 Conversion_Error_N
12325 -- If the interpretation involves a standard operator, use
12326 -- the location of the type, which may be user-defined.
12330 else
12334 Conversion_Error_N -- CODEFIX
12339 else
12343 Conversion_Error_N -- CODEFIX
12355 -- Deal with conversion of integer type to address if the pragma
12356 -- Allow_Integer_Address is in effect. We convert the conversion to
12357 -- an unchecked conversion in this case and we are all done.
12365 -- If we are within a child unit, check whether the type of the
12366 -- expression has an ancestor in a parent unit, in which case it
12367 -- belongs to its derivation class even if the ancestor is private.
12368 -- See RM 7.3.1 (5.2/3).
12372 -- Numeric types
12376 -- A universal fixed expression can be converted to any numeric type
12381 -- Also no need to check when in an instance or inlined body, because
12382 -- the legality has been established when the template was analyzed.
12383 -- Furthermore, numeric conversions may occur where only a private
12384 -- view of the operand type is visible at the instantiation point.
12385 -- This results in a spurious error if we check that the operand type
12386 -- is a numeric type.
12388 -- Note: in a previous version of this unit, the following tests were
12389 -- applied only for generated code (Comes_From_Source set to False),
12390 -- but in fact the test is required for source code as well, since
12391 -- this situation can arise in source code.
12396 -- Otherwise we need the conversion check
12398 else
12399 return Conversion_Check
12401 or else
12407 -- Array types
12413 then
12414 Conversion_Error_N
12418 else
12422 -- Ada 2005 (AI-251): Internally generated conversions of access to
12423 -- interface types added to force the displacement of the pointer to
12424 -- reference the corresponding dispatch table.
12429 then
12432 -- Ada 2005 (AI-251): Anonymous access types where target references an
12433 -- interface type.
12437 E_Anonymous_Access_Type)
12439 then
12440 -- Check the static accessibility rule of 4.6(17). Note that the
12441 -- check is not enforced when within an instance body, since the
12442 -- RM requires such cases to be caught at run time.
12444 -- If the operand is a rewriting of an allocator no check is needed
12445 -- because there are no accessibility issues.
12453 then
12454 -- In an instance, this is a run-time check, but one we know
12455 -- will fail, so generate an appropriate warning. The raise
12456 -- will be generated by Expand_N_Type_Conversion.
12460 Conversion_Error_N
12462 Operand);
12465 else
12466 Conversion_Error_N
12468 Operand);
12472 -- Special accessibility checks are needed in the case of access
12473 -- discriminants declared for a limited type.
12477 then
12478 -- When the operand is a selected access discriminant the check
12479 -- needs to be made against the level of the object denoted by
12480 -- the prefix of the selected name (Object_Access_Level handles
12481 -- checking the prefix of the operand for this case).
12486 then
12487 -- In an instance, this is a run-time check, but one we know
12488 -- will fail, so generate an appropriate warning. The raise
12489 -- will be generated by Expand_N_Type_Conversion.
12493 Conversion_Error_N
12498 -- Real error if not in instance body
12500 else
12501 Conversion_Error_N
12508 -- The case of a reference to an access discriminant from
12509 -- within a limited type declaration (which will appear as
12510 -- a discriminal) is always illegal because the level of the
12511 -- discriminant is considered to be deeper than any (nameable)
12512 -- access type.
12516 and then
12519 then
12520 Conversion_Error_N
12522 Operand);
12530 -- General and anonymous access types
12533 E_Anonymous_Access_Type)
12534 and then
12535 Conversion_Check
12537 and then not
12539 E_Access_Protected_Subprogram_Type),
12541 then
12544 then
12545 Conversion_Error_N
12550 -- Check the static accessibility rule of 4.6(17). Note that the
12551 -- check is not enforced when within an instance body, since the RM
12552 -- requires such cases to be caught at run time.
12557 N_Object_Declaration
12558 then
12559 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12560 -- conversions from an anonymous access type to a named general
12561 -- access type. Such conversions are not allowed in the case of
12562 -- access parameters and stand-alone objects of an anonymous
12563 -- access type. The implicit conversion case is recognized by
12564 -- testing that Comes_From_Source is False and that it's been
12565 -- rewritten. The Comes_From_Source test isn't sufficient because
12566 -- nodes in inlined calls to predefined library routines can have
12567 -- Comes_From_Source set to False. (Is there a better way to test
12568 -- for implicit conversions???)
12575 then
12578 -- Implicit conversions aren't allowed for objects of an
12579 -- anonymous access type, since such objects have nonstatic
12580 -- levels in Ada 2012.
12583 N_Object_Declaration
12584 then
12585 Conversion_Error_N
12590 -- Implicit conversions aren't allowed for anonymous access
12591 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12592 -- is done to exclude anonymous access results.
12596 N_Function_Specification,
12597 N_Procedure_Specification)
12598 then
12599 Conversion_Error_N
12604 -- This is a case where there's an enclosing object whose
12605 -- to which the "statically deeper than" relationship does
12606 -- not apply (such as an access discriminant selected from
12607 -- a dereference of an access parameter).
12611 then
12612 Conversion_Error_N
12617 -- In other cases, the level of the operand's type must be
12618 -- statically less deep than that of the target type, else
12619 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12623 then
12624 Conversion_Error_N
12633 then
12634 -- In an instance, this is a run-time check, but one we know
12635 -- will fail, so generate an appropriate warning. The raise
12636 -- will be generated by Expand_N_Type_Conversion.
12640 Conversion_Error_N
12642 Operand);
12645 -- If not in an instance body, this is a real error
12647 else
12648 -- Avoid generation of spurious error message
12651 Conversion_Error_N
12653 Operand);
12659 -- Special accessibility checks are needed in the case of access
12660 -- discriminants declared for a limited type.
12664 then
12665 -- When the operand is a selected access discriminant the check
12666 -- needs to be made against the level of the object denoted by
12667 -- the prefix of the selected name (Object_Access_Level handles
12668 -- checking the prefix of the operand for this case).
12673 then
12674 -- In an instance, this is a run-time check, but one we know
12675 -- will fail, so generate an appropriate warning. The raise
12676 -- will be generated by Expand_N_Type_Conversion.
12680 Conversion_Error_N
12685 -- If not in an instance body, this is a real error
12687 else
12688 Conversion_Error_N
12695 -- The case of a reference to an access discriminant from
12696 -- within a limited type declaration (which will appear as
12697 -- a discriminal) is always illegal because the level of the
12698 -- discriminant is considered to be deeper than any (nameable)
12699 -- access type.
12702 and then
12705 then
12706 Conversion_Error_N
12708 Operand);
12714 -- In the presence of limited_with clauses we have to use nonlimited
12715 -- views, if available.
12719 -- Helper function to handle limited views
12721 --------------------------
12722 -- Full_Designated_Type --
12723 --------------------------
12728 begin
12729 -- Handle the limited view of a type
12733 then
12735 else
12740 -- Local Declarations
12748 -- Start of processing for Check_Limited
12750 begin
12754 else
12756 Conversion_Error_NE
12761 -- Ada 2005 AI-384: legality rule is symmetric in both
12762 -- designated types. The conversion is legal (with possible
12763 -- constraint check) if either designated type is
12764 -- unconstrained.
12767 or else
12769 and then
12772 then
12773 -- Special case, if Value_Size has been used to make the
12774 -- sizes different, the conversion is not allowed even
12775 -- though the subtypes statically match.
12780 then
12781 Conversion_Error_NE
12784 Conversion_Error_NE
12789 -- Normal case where conversion is allowed
12791 else
12795 else
12796 Error_Msg_NE
12804 -- Access to subprogram types. If the operand is an access parameter,
12805 -- the type has a deeper accessibility that any master, and cannot be
12806 -- assigned. We must make an exception if the conversion is part of an
12807 -- assignment and the target is the return object of an extended return
12808 -- statement, because in that case the accessibility check takes place
12809 -- after the return.
12813 -- Note: this test of Opnd_Type is there to prevent entering this
12814 -- branch in the case of a remote access to subprogram type, which
12815 -- is internally represented as an E_Record_Type.
12818 then
12822 and then
12826 then
12827 Conversion_Error_N
12829 Operand);
12830 Conversion_Error_N
12833 Operand);
12835 Error_Msg_NE
12840 -- Check that the designated types are subtype conformant
12846 -- Check the static accessibility rule of 4.6(20)
12850 then
12851 Conversion_Error_N
12853 Operand);
12855 -- Check that if the operand type is declared in a generic body,
12856 -- then the target type must be declared within that same body
12857 -- (enforces last sentence of 4.6(20)).
12860 declare
12866 begin
12873 Conversion_Error_N
12882 -- Remote access to subprogram types
12886 then
12887 -- It is valid to convert from one RAS type to another provided
12888 -- that their specification statically match.
12890 -- Note: at this point, remote access to subprogram types have been
12891 -- expanded to their E_Record_Type representation, and we need to
12892 -- go back to the original access type definition using the
12893 -- Corresponding_Remote_Type attribute in order to check that the
12894 -- designated profiles match.
12899 Check_Subtype_Conformant
12902 Old_Id =>
12904 Err_Loc =>
12905 N);
12908 -- If it was legal in the generic, it's legal in the instance
12913 -- If both are tagged types, check legality of view conversions
12916 and then
12918 then
12921 -- Types derived from the same root type are convertible
12926 -- In an instance or an inlined body, there may be inconsistent views of
12927 -- the same type, or of types derived from a common root.
12930 and then
12933 then
12936 -- Special check for common access type error case
12940 then
12942 Conversion_Error_NE -- CODEFIX
12946 -- Here we have a real conversion error
12948 else
12949 Conversion_Error_NE