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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2017, 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 -- Ensure that the corresponding operator has the same parent as the
1329 -- original call. This guarantees that parent traversals performed by
1330 -- the ABE mechanism succeed.
1334 -- Binary operator
1344 -- Unary operator
1346 else
1352 -- If the operator is denoted by an expanded name, and the prefix is
1353 -- not Standard, but the operator is a predefined one whose scope is
1354 -- Standard, then this is an implicit_operator, inserted as an
1355 -- interpretation by the procedure of the same name. This procedure
1356 -- overestimates the presence of implicit operators, because it does
1357 -- not examine the type of the operands. Verify now that the operand
1358 -- type appears in the given scope. If right operand is universal,
1359 -- check the other operand. In the case of concatenation, either
1360 -- argument can be the component type, so check the type of the result.
1361 -- If both arguments are literals, look for a type of the right kind
1362 -- defined in the given scope. This elaborate nonsense is brought to
1363 -- you courtesy of b33302a. The type itself must be frozen, so we must
1364 -- find the type of the proper class in the given scope.
1366 -- A final wrinkle is the multiplication operator for fixed point types,
1367 -- which is defined in Standard only, and not in the scope of the
1368 -- fixed point type itself.
1373 -- If this is a package renaming, get renamed entity, which will be
1374 -- the scope of the operands if operaton is type-correct.
1380 -- If the entity being called is defined in the given package, it is
1381 -- a renaming of a predefined operator, and known to be legal.
1385 then
1388 -- Visibility does not need to be checked in an instance: if the
1389 -- operator was not visible in the generic it has been diagnosed
1390 -- already, else there is an implicit copy of it in the instance.
1398 then
1403 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1404 -- available.
1409 then
1412 else
1421 and then Is_Binary
1423 then
1429 -- Verify that the scope contains a type that corresponds to
1430 -- the given literal. Optimize the case where Pack is Standard.
1451 else
1460 else
1469 then
1472 -- If the type is defined elsewhere, and the operator is not
1473 -- defined in the given scope (by a renaming declaration, e.g.)
1474 -- then this is an error as well. If an extension of System is
1475 -- present, and the type may be defined there, Pack must be
1476 -- System itself.
1483 then
1486 else
1492 then
1499 Error_Msg_NE
1504 -- Detect a mismatch between the context type and the result type
1505 -- in the named package, which is otherwise not detected if the
1506 -- operands are universal. Check is only needed if source entity is
1507 -- an operator, not a function that renames an operator.
1514 and then not In_Instance
1515 then
1518 then
1519 -- Already checked above
1523 -- Operator may be defined in an extension of System
1527 then
1530 else
1531 -- Could we use Wrong_Type here??? (this would require setting
1532 -- Etype (N) to the actual type found where Typ was expected).
1543 else
1547 -- If this is a call to a function that renames a predefined equality,
1548 -- the renaming declaration provides a type that must be used to
1549 -- resolve the operands. This must be done now because resolution of
1550 -- the equality node will not resolve any remaining ambiguity, and it
1551 -- assumes that the first operand is not overloaded.
1556 then
1564 -- Do rewrite setting Comes_From_Source on the result if the original
1565 -- call came from source. Although it is not strictly the case that the
1566 -- operator as such comes from the source, logically it corresponds
1567 -- exactly to the function call in the source, so it should be marked
1568 -- this way (e.g. to make sure that validity checks work fine).
1570 declare
1572 begin
1577 -- If this is an arithmetic operator and the result type is private,
1578 -- the operands and the result must be wrapped in conversion to
1579 -- expose the underlying numeric type and expand the proper checks,
1580 -- e.g. on division.
1584 when N_Op_Add
1585 | N_Op_Divide
1586 | N_Op_Expon
1587 | N_Op_Mod
1588 | N_Op_Multiply
1589 | N_Op_Rem
1590 | N_Op_Subtract
1591 =>
1594 when N_Op_Abs
1595 | N_Op_Minus
1596 | N_Op_Plus
1597 =>
1603 else
1607 -- If in ASIS_Mode, propagate operand types to original actuals of
1608 -- function call, which would otherwise not be fully resolved. If
1609 -- the call has already been constant-folded, nothing to do. We
1610 -- relocate the operand nodes rather than copy them, to preserve
1611 -- original_node pointers, given that the operands themselves may
1612 -- have been rewritten. If the call was itself a rewriting of an
1613 -- operator node, nothing to do.
1615 if ASIS_Mode
1618 then
1619 declare
1627 begin
1632 -- If the original call has named associations, replace the
1633 -- explicit actual parameter in the association with the proper
1634 -- resolved operand.
1639 then
1642 else
1647 else
1654 then
1657 else
1662 else
1666 else
1670 else
1680 -------------------
1681 -- Operator_Kind --
1682 -------------------
1684 function Operator_Kind
1687 is
1690 begin
1691 -- Use CASE statement or array???
1728 else
1732 -- Unary operators
1734 else
1743 else
1751 ----------------------------
1752 -- Preanalyze_And_Resolve --
1753 ----------------------------
1758 begin
1762 -- Normally, we suppress all checks for this preanalysis. There is no
1763 -- point in processing them now, since they will be applied properly
1764 -- and in the proper location when the default expressions reanalyzed
1765 -- and reexpanded later on. We will also have more information at that
1766 -- point for possible suppression of individual checks.
1768 -- However, in SPARK mode, most expansion is suppressed, and this
1769 -- later reanalysis and reexpansion may not occur. SPARK mode does
1770 -- require the setting of checking flags for proof purposes, so we
1771 -- do the SPARK preanalysis without suppressing checks.
1773 -- This special handling for SPARK mode is required for example in the
1774 -- case of Ada 2012 constructs such as quantified expressions, which are
1775 -- expanded in two separate steps.
1779 else
1783 Expander_Mode_Restore;
1787 -- Version without context type
1792 begin
1799 Expander_Mode_Restore;
1803 ----------------------------------
1804 -- Replace_Actual_Discriminants --
1805 ----------------------------------
1812 -- Comment needed???
1814 -------------------
1815 -- Process_Discr --
1816 -------------------
1821 begin
1827 then
1843 -- Start of processing for Replace_Actual_Discriminants
1845 begin
1849 -- Allow the replacement of concurrent discriminants in GNATprove even
1850 -- though this is a light expansion activity. Note that generic units
1851 -- are not modified.
1856 else
1872 -------------
1873 -- Resolve --
1874 -------------
1890 -- Determine whether a node comes from a predefined library unit or
1891 -- Standard.
1894 -- Try and fix up a literal so that it matches its expected type. New
1895 -- literals are manufactured if necessary to avoid cascaded errors.
1898 -- Additional diagnostics when an ambiguous call has an ambiguous
1899 -- argument (typically a controlling actual).
1902 -- Called when attempt at resolving current expression fails
1904 ------------------------------------
1905 -- Comes_From_Predefined_Lib_Unit --
1906 -------------------------------------
1909 begin
1910 return
1914 --------------------
1915 -- Patch_Up_Value --
1916 --------------------
1919 begin
1936 then
1941 Char_Literal_Value =>
1957 -------------------------------
1958 -- Report_Ambiguous_Argument --
1959 -------------------------------
1966 begin
1970 then
1973 -- Could use comments on what is going on here???
1981 else
1990 -----------------------
1991 -- Resolution_Failed --
1992 -----------------------
1995 begin
1998 -- Set the type to the desired one to minimize cascaded errors. Note
1999 -- that this is an approximation and does not work in all cases.
2006 -- The caller will return without calling the expander, so we need
2007 -- to set the analyzed flag. Note that it is fine to set Analyzed
2008 -- to True even if we are in the middle of a shallow analysis,
2009 -- (see the spec of sem for more details) since this is an error
2010 -- situation anyway, and there is no point in repeating the
2011 -- analysis later (indeed it won't work to repeat it later, since
2012 -- we haven't got a clear resolution of which entity is being
2013 -- referenced.)
2019 -- Start of processing for Resolve
2021 begin
2026 -- Access attribute on remote subprogram cannot be used for a non-remote
2027 -- access-to-subprogram type.
2031 Name_Unrestricted_Access,
2032 Name_Unchecked_Access)
2038 then
2039 Error_Msg_N
2045 -- If the context is a Remote_Access_To_Subprogram, access attributes
2046 -- must be resolved with the corresponding fat pointer. There is no need
2047 -- to check for the attribute name since the return type of an
2048 -- attribute is never a remote type.
2053 then
2054 declare
2062 begin
2063 -- Check that Typ is a remote access-to-subprogram type
2067 -- Prefix (N) must statically denote a remote subprogram
2068 -- declared in a package specification.
2072 Attr = Attribute_Unrestricted_Access
2073 then
2088 or else
2090 then
2092 Error_Msg_N
2094 N);
2097 -- If we are generating code in distributed mode, perform
2098 -- semantic checks against corresponding remote entities.
2100 if Expander_Active
2102 then
2103 Check_Subtype_Conformant
2105 Old_Id => Designated_Type
2131 then
2136 -- Return if already analyzed
2143 -- Any case of Any_Type as the Etype value means that we had a
2144 -- previous error.
2153 -- The resolution of an Expression_With_Actions is determined by
2154 -- its Expression.
2162 -- If not overloaded, then we know the type, and all that needs doing
2163 -- is to check that this type is compatible with the context.
2169 -- In the overloaded case, we must select the interpretation that
2170 -- is compatible with the context (i.e. the type passed to Resolve)
2172 else
2173 -- Loop through possible interpretations
2182 -- We are only interested in interpretations that are compatible
2183 -- with the expected type, any other interpretations are ignored.
2188 Write_Eol;
2191 else
2192 -- Skip the current interpretation if it is disabled by an
2193 -- abstract operator. This action is performed only when the
2194 -- type against which we are resolving is the same as the
2195 -- type of the interpretation.
2202 then
2210 -- First matching interpretation
2218 -- Matching interpretation that is not the first, maybe an
2219 -- error, but there are some cases where preference rules are
2220 -- used to choose between the two possibilities. These and
2221 -- some more obscure cases are handled in Disambiguate.
2223 else
2224 -- If the current statement is part of a predefined library
2225 -- unit, then all interpretations which come from user level
2226 -- packages should not be considered. Check previous and
2227 -- current one.
2235 -- Previous interpretation must be discarded
2245 -- Otherwise apply further disambiguation steps
2250 -- Disambiguation has succeeded. Skip the remaining
2251 -- interpretations.
2261 else
2262 -- Before we issue an ambiguity complaint, check for the
2263 -- case of a subprogram call where at least one of the
2264 -- arguments is Any_Type, and if so suppress the message,
2265 -- since it is a cascaded error. This can also happen for
2266 -- a generalized indexing operation.
2271 then
2272 declare
2276 begin
2292 Write_Eol;
2305 then
2310 then
2314 -- Not that special case, so issue message using the flag
2315 -- Ambiguous to control printing of the header message
2316 -- only at the start of an ambiguous set.
2321 then
2322 Error_Msg_N
2325 else
2326 Error_Msg_NE -- CODEFIX
2334 Error_Msg_N
2336 else
2337 Error_Msg_N -- CODEFIX
2343 then
2344 Report_Ambiguous_Argument;
2350 -- By default, the error message refers to the candidate
2351 -- interpretation. But if it is a predefined operator, it
2352 -- is implicitly declared at the declaration of the type
2353 -- of the operand. Recover the sloc of that declaration
2354 -- for the error message.
2360 Standard_Standard
2361 then
2366 then
2374 Standard_Standard
2375 then
2380 then
2384 -- If this is an indirect call, use the subprogram_type
2385 -- in the message, to have a meaningful location. Also
2386 -- indicate if this is an inherited operation, created
2387 -- by a type declaration.
2392 then
2394 Error_Msg_Sloc :=
2396 else
2403 then
2404 -- Special-case the message for universal_fixed
2405 -- operators, which are not declared with the type
2406 -- of the operand, but appear forever in Standard.
2410 then
2411 Error_Msg_N
2414 else
2415 Error_Msg_N
2419 elsif
2421 then
2422 Error_Msg_N
2424 else
2425 Error_Msg_N -- CODEFIX
2432 -- We have a matching interpretation, Expr_Type is the type
2433 -- from this interpretation, and Seen is the entity.
2435 -- For an operator, just set the entity name. The type will be
2436 -- set by the specific operator resolution routine.
2451 -- AI05-0139-2: Expression is overloaded because type has
2452 -- implicit dereference. If type matches context, no implicit
2453 -- dereference is involved.
2464 then
2465 -- If the node is a general indexing, the dereference is
2466 -- is inserted when resolving the rewritten form, else
2467 -- insert it now.
2471 then
2475 -- For an explicit dereference, attribute reference, range,
2476 -- short-circuit form (which is not an operator node), or call
2477 -- with a name that is an explicit dereference, there is
2478 -- nothing to be done at this point.
2481 N_And_Then,
2482 N_Explicit_Dereference,
2483 N_Identifier,
2484 N_Indexed_Component,
2485 N_Or_Else,
2486 N_Range,
2487 N_Selected_Component,
2488 N_Slice)
2490 then
2493 -- For procedure or function calls, set the type of the name,
2494 -- and also the entity pointer for the prefix.
2498 then
2505 then
2510 -- For all other cases, just set the type of the Name
2512 else
2520 -- Move to next interpretation
2528 -- At this stage Found indicates whether or not an acceptable
2529 -- interpretation exists. If not, then we have an error, except that if
2530 -- the context is Any_Type as a result of some other error, then we
2531 -- suppress the error report.
2536 -- If type we are looking for is Void, then this is the procedure
2537 -- call case, and the error is simply that what we gave is not a
2538 -- procedure name (we think of procedure calls as expressions with
2539 -- types internally, but the user doesn't think of them this way).
2543 -- Special case message if function used as a procedure
2548 then
2549 Error_Msg_NE
2552 Error_Msg_N
2556 -- Otherwise give general message (not clear what cases this
2557 -- covers, but no harm in providing for them).
2559 else
2565 -- Otherwise we do have a subexpression with the wrong type
2567 -- Check for the case of an allocator which uses an access type
2568 -- instead of the designated type. This is a common error and we
2569 -- specialize the message, posting an error on the operand of the
2570 -- allocator, complaining that we expected the designated type of
2571 -- the allocator.
2577 then
2581 -- Check for view mismatch on Null in instances, for which the
2582 -- view-swapping mechanism has no identifier.
2588 then
2593 -- Check for an aggregate. Sometimes we can get bogus aggregates
2594 -- from misuse of parentheses, and we are about to complain about
2595 -- the aggregate without even looking inside it.
2597 -- Instead, if we have an aggregate of type Any_Composite, then
2598 -- analyze and resolve the component fields, and then only issue
2599 -- another message if we get no errors doing this (otherwise
2600 -- assume that the errors in the aggregate caused the problem).
2604 then
2605 -- Disable expansion in any case. If there is a type mismatch
2606 -- it may be fatal to try to expand the aggregate. The flag
2607 -- would otherwise be set to false when the error is posted.
2611 declare
2613 -- Check one aggregate, and set Found to True if we have a
2614 -- definite error in any of its elements
2617 -- Check one element of aggregate and set Found to True if
2618 -- we definitely have an error in the element.
2620 ----------------
2621 -- Check_Aggr --
2622 ----------------
2627 begin
2640 -- If this is a default-initialized component, then
2641 -- there is nothing to check. The box will be
2642 -- replaced by the appropriate call during late
2643 -- expansion.
2647 then
2656 ----------------
2657 -- Check_Elmt --
2658 ----------------
2661 begin
2662 -- If we have a nested aggregate, go inside it (to
2663 -- attempt a naked analyze-resolve of the aggregate can
2664 -- cause undesirable cascaded errors). Do not resolve
2665 -- expression if it needs a type from context, as for
2666 -- integer * fixed expression.
2671 else
2676 then
2686 begin
2691 -- Looks like we have a type error, but check for special case
2692 -- of Address wanted, integer found, with the configuration pragma
2693 -- Allow_Integer_Address active. If we have this case, introduce
2694 -- an unchecked conversion to allow the integer expression to be
2695 -- treated as an Address. The reverse case of integer wanted,
2696 -- Address found, is treated in an analogous manner.
2703 -- Under relaxed RM semantics silently replace occurrences of null
2704 -- by System.Address_Null.
2712 -- That special Allow_Integer_Address check did not apply, so we
2713 -- have a real type error. If an error message was issued already,
2714 -- Found got reset to True, so if it's still False, issue standard
2715 -- Wrong_Type message.
2719 declare
2722 begin
2728 -- Protected operation: retrieve operation name
2732 else
2737 Error_Msg_NE
2743 declare
2747 begin
2754 Error_Msg_NE
2760 else
2764 else
2770 Resolution_Failed;
2773 -- Test if we have more than one interpretation for the context
2776 Resolution_Failed;
2779 -- Only one intepretation
2781 else
2782 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2783 -- the "+" on T is abstract, and the operands are of universal type,
2784 -- the above code will have (incorrectly) resolved the "+" to the
2785 -- universal one in Standard. Therefore check for this case and give
2786 -- an error. We can't do this earlier, because it would cause legal
2787 -- cases to get errors (when some other type has an abstract "+").
2793 then
2798 then
2799 Error_Msg_NE
2808 -- Here we have an acceptable interpretation for the context
2810 -- Propagate type information and normalize tree for various
2811 -- predefined operations. If the context only imposes a class of
2812 -- types, rather than a specific type, propagate the actual type
2813 -- downward.
2819 Typ = Any_Discrete
2820 then
2823 -- Any_Fixed is legal in a real context only if a specific fixed-
2824 -- point type is imposed. If Norman Cohen can be confused by this,
2825 -- it deserves a separate message.
2829 then
2836 -- A user-defined operator is transformed into a function call at
2837 -- this point, so that further processing knows that operators are
2838 -- really operators (i.e. are predefined operators). User-defined
2839 -- operators that are intrinsic are just renamings of the predefined
2840 -- ones, and need not be turned into calls either, but if they rename
2841 -- a different operator, we must transform the node accordingly.
2842 -- Instantiations of Unchecked_Conversion are intrinsic but are
2843 -- treated as functions, even if given an operator designator.
2848 then
2853 and then
2855 N_Subprogram_Renaming_Declaration
2856 then
2859 -- If the node is rewritten, it will be fully resolved in
2860 -- Rewrite_Renamed_Operator.
2869 when N_Aggregate =>
2870 Resolve_Aggregate (N, Ctx_Type);
2872 when N_Allocator =>
2873 Resolve_Allocator (N, Ctx_Type);
2875 when N_Short_Circuit =>
2876 Resolve_Short_Circuit (N, Ctx_Type);
2878 when N_Attribute_Reference =>
2879 Resolve_Attribute (N, Ctx_Type);
2881 when N_Case_Expression =>
2882 Resolve_Case_Expression (N, Ctx_Type);
2884 when N_Character_Literal =>
2885 Resolve_Character_Literal (N, Ctx_Type);
2887 when N_Delta_Aggregate =>
2888 Resolve_Delta_Aggregate (N, Ctx_Type);
2890 when N_Expanded_Name =>
2891 Resolve_Entity_Name (N, Ctx_Type);
2893 when N_Explicit_Dereference =>
2894 Resolve_Explicit_Dereference (N, Ctx_Type);
2896 when N_Expression_With_Actions =>
2897 Resolve_Expression_With_Actions (N, Ctx_Type);
2899 when N_Extension_Aggregate =>
2900 Resolve_Extension_Aggregate (N, Ctx_Type);
2902 when N_Function_Call =>
2903 Resolve_Call (N, Ctx_Type);
2905 when N_Identifier =>
2906 Resolve_Entity_Name (N, Ctx_Type);
2908 when N_If_Expression =>
2909 Resolve_If_Expression (N, Ctx_Type);
2911 when N_Indexed_Component =>
2912 Resolve_Indexed_Component (N, Ctx_Type);
2914 when N_Integer_Literal =>
2915 Resolve_Integer_Literal (N, Ctx_Type);
2917 when N_Membership_Test =>
2918 Resolve_Membership_Op (N, Ctx_Type);
2920 when N_Null =>
2921 Resolve_Null (N, Ctx_Type);
2923 when N_Op_And
2924 | N_Op_Or
2925 | N_Op_Xor
2926 =>
2927 Resolve_Logical_Op (N, Ctx_Type);
2929 when N_Op_Eq
2930 | N_Op_Ne
2931 =>
2932 Resolve_Equality_Op (N, Ctx_Type);
2934 when N_Op_Ge
2935 | N_Op_Gt
2936 | N_Op_Le
2937 | N_Op_Lt
2938 =>
2939 Resolve_Comparison_Op (N, Ctx_Type);
2941 when N_Op_Not =>
2942 Resolve_Op_Not (N, Ctx_Type);
2944 when N_Op_Add
2945 | N_Op_Divide
2946 | N_Op_Mod
2947 | N_Op_Multiply
2948 | N_Op_Rem
2949 | N_Op_Subtract
2950 =>
2951 Resolve_Arithmetic_Op (N, Ctx_Type);
2953 when N_Op_Concat =>
2954 Resolve_Op_Concat (N, Ctx_Type);
2956 when N_Op_Expon =>
2957 Resolve_Op_Expon (N, Ctx_Type);
2959 when N_Op_Abs
2960 | N_Op_Minus
2961 | N_Op_Plus
2962 =>
2963 Resolve_Unary_Op (N, Ctx_Type);
2965 when N_Op_Shift =>
2966 Resolve_Shift (N, Ctx_Type);
2968 when N_Procedure_Call_Statement =>
2969 Resolve_Call (N, Ctx_Type);
2971 when N_Operator_Symbol =>
2972 Resolve_Operator_Symbol (N, Ctx_Type);
2974 when N_Qualified_Expression =>
2975 Resolve_Qualified_Expression (N, Ctx_Type);
2977 -- Why is the following null, needs a comment ???
2979 when N_Quantified_Expression =>
2980 null;
2982 when N_Raise_Expression =>
2983 Resolve_Raise_Expression (N, Ctx_Type);
2985 when N_Raise_xxx_Error =>
2986 Set_Etype (N, Ctx_Type);
2988 when N_Range =>
2989 Resolve_Range (N, Ctx_Type);
2991 when N_Real_Literal =>
2992 Resolve_Real_Literal (N, Ctx_Type);
2994 when N_Reference =>
2995 Resolve_Reference (N, Ctx_Type);
2997 when N_Selected_Component =>
2998 Resolve_Selected_Component (N, Ctx_Type);
3000 when N_Slice =>
3001 Resolve_Slice (N, Ctx_Type);
3003 when N_String_Literal =>
3004 Resolve_String_Literal (N, Ctx_Type);
3006 when N_Target_Name =>
3007 Resolve_Target_Name (N, Ctx_Type);
3009 when N_Type_Conversion =>
3010 Resolve_Type_Conversion (N, Ctx_Type);
3012 when N_Unchecked_Expression =>
3013 Resolve_Unchecked_Expression (N, Ctx_Type);
3015 when N_Unchecked_Type_Conversion =>
3016 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3017 end case;
3019 -- Mark relevant use-type and use-package clauses as effective using
3020 -- the original node because constant folding may have occured and
3021 -- removed references that need to be examined.
3023 if Nkind (Original_Node (N)) in N_Op then
3024 Mark_Use_Clauses (Original_Node (N));
3025 end if;
3027 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3028 -- expression of an anonymous access type that occurs in the context
3029 -- of a named general access type, except when the expression is that
3030 -- of a membership test. This ensures proper legality checking in
3031 -- terms of allowed conversions (expressions that would be illegal to
3032 -- convert implicitly are allowed in membership tests).
3034 if Ada_Version >= Ada_2012
3035 and then Ekind (Ctx_Type) = E_General_Access_Type
3036 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3037 and then Nkind (Parent (N)) not in N_Membership_Test
3038 then
3039 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3040 Analyze_And_Resolve (N, Ctx_Type);
3041 end if;
3043 -- If the subexpression was replaced by a non-subexpression, then
3044 -- all we do is to expand it. The only legitimate case we know of
3045 -- is converting procedure call statement to entry call statements,
3046 -- but there may be others, so we are making this test general.
3048 if Nkind (N) not in N_Subexpr then
3049 Debug_A_Exit ("resolving ", N, " (done)");
3050 Expand (N);
3051 return;
3052 end if;
3054 -- The expression is definitely NOT overloaded at this point, so
3055 -- we reset the Is_Overloaded flag to avoid any confusion when
3056 -- reanalyzing the node.
3058 Set_Is_Overloaded (N, False);
3060 -- Freeze expression type, entity if it is a name, and designated
3061 -- type if it is an allocator (RM 13.14(10,11,13)).
3063 -- Now that the resolution of the type of the node is complete, and
3064 -- we did not detect an error, we can expand this node. We skip the
3065 -- expand call if we are in a default expression, see section
3066 -- "Handling of Default Expressions" in Sem spec.
3068 Debug_A_Exit ("resolving ", N, " (done)");
3070 -- We unconditionally freeze the expression, even if we are in
3071 -- default expression mode (the Freeze_Expression routine tests this
3072 -- flag and only freezes static types if it is set).
3074 -- Ada 2012 (AI05-177): The declaration of an expression function
3075 -- does not cause freezing, but we never reach here in that case.
3076 -- Here we are resolving the corresponding expanded body, so we do
3077 -- need to perform normal freezing.
3079 -- As elsewhere we do not emit freeze node within a generic. We make
3080 -- an exception for entities that are expressions, only to detect
3081 -- misuses of deferred constants and preserve the output of various
3082 -- tests.
3084 if not Inside_A_Generic or else Is_Entity_Name (N) then
3085 Freeze_Expression (N);
3086 end if;
3088 -- Now we can do the expansion
3090 Expand (N);
3091 end if;
3092 end Resolve;
3094 -------------
3095 -- Resolve --
3096 -------------
3098 -- Version with check(s) suppressed
3100 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3101 begin
3102 if Suppress = All_Checks then
3103 declare
3104 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3105 begin
3106 Scope_Suppress.Suppress := (others => True);
3107 Resolve (N, Typ);
3108 Scope_Suppress.Suppress := Sva;
3109 end;
3111 else
3112 declare
3113 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3114 begin
3115 Scope_Suppress.Suppress (Suppress) := True;
3116 Resolve (N, Typ);
3117 Scope_Suppress.Suppress (Suppress) := Svg;
3118 end;
3119 end if;
3120 end Resolve;
3122 -------------
3123 -- Resolve --
3124 -------------
3126 -- Version with implicit type
3128 procedure Resolve (N : Node_Id) is
3129 begin
3130 Resolve (N, Etype (N));
3131 end Resolve;
3133 ---------------------
3134 -- Resolve_Actuals --
3135 ---------------------
3137 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3138 Loc : constant Source_Ptr := Sloc (N);
3139 A : Node_Id;
3140 A_Id : Entity_Id;
3141 A_Typ : Entity_Id;
3142 F : Entity_Id;
3143 F_Typ : Entity_Id;
3144 Prev : Node_Id := Empty;
3145 Orig_A : Node_Id;
3146 Real_F : Entity_Id;
3148 Real_Subp : Entity_Id;
3149 -- If the subprogram being called is an inherited operation for
3150 -- a formal derived type in an instance, Real_Subp is the subprogram
3151 -- that will be called. It may have different formal names than the
3152 -- operation of the formal in the generic, so after actual is resolved
3153 -- the name of the actual in a named association must carry the name
3154 -- of the actual of the subprogram being called.
3156 procedure Check_Aliased_Parameter;
3157 -- Check rules on aliased parameters and related accessibility rules
3158 -- in (RM 3.10.2 (10.2-10.4)).
3160 procedure Check_Argument_Order;
3161 -- Performs a check for the case where the actuals are all simple
3162 -- identifiers that correspond to the formal names, but in the wrong
3163 -- order, which is considered suspicious and cause for a warning.
3165 procedure Check_Prefixed_Call;
3166 -- If the original node is an overloaded call in prefix notation,
3168 -- Try_Object_Operation has already verified that there is a valid
3169 -- interpretation, but the form of the actual can only be determined
3170 -- once the primitive operation is identified.
3173 -- Emit an error concerning the illegal usage of an effectively volatile
3174 -- object in interfering context (SPARK RM 7.13(12)).
3177 -- If the actual is missing in a call, insert in the actuals list
3178 -- an instance of the default expression. The insertion is always
3179 -- a named association.
3182 -- Check whether T1 and T2, or their full views, are derived from a
3183 -- common type. Used to enforce the restrictions on array conversions
3184 -- of AI95-00246.
3187 -- Predicate to determine whether an actual that is a concatenation
3188 -- will be evaluated statically and does not need a transient scope.
3189 -- This must be determined before the actual is resolved and expanded
3190 -- because if needed the transient scope must be introduced earlier.
3192 -----------------------------
3193 -- Check_Aliased_Parameter --
3194 -----------------------------
3199 begin
3207 else
3214 -- In a generic body assume the worst for generic formals:
3215 -- they can have a constrained partial view (AI05-041).
3221 then
3224 else
3229 else
3241 then
3249 then
3250 Error_Msg_N
3256 --------------------------
3257 -- Check_Argument_Order --
3258 --------------------------
3261 begin
3262 -- Nothing to do if no parameters, or original node is neither a
3263 -- function call nor a procedure call statement (happens in the
3264 -- operator-transformed-to-function call case), or the call does
3265 -- not come from source, or this warning is off.
3267 if not Warn_On_Parameter_Order
3271 then
3275 declare
3278 begin
3279 -- Nothing to do if only one parameter
3285 -- Here if at least two arguments
3287 declare
3293 -- Set True if an out of order case is found
3295 begin
3296 -- Collect identifier names of actuals, fail if any actual is
3297 -- not a simple identifier, and record max length of name.
3303 else
3309 -- If we got this far, all actuals are identifiers and the list
3310 -- of their names is stored in the Actuals array.
3315 -- If we ran out of formals, that's odd, probably an error
3316 -- which will be detected elsewhere, but abandon the search.
3322 -- If name matches and is in order OK
3327 else
3328 -- If no match, see if it is elsewhere in list and if so
3329 -- flag potential wrong order if type is compatible.
3333 and then
3335 then
3341 -- No match
3349 -- If Formals left over, also probably an error, skip warning
3355 -- Here we give the warning if something was out of order
3358 Error_Msg_N
3365 -------------------------
3366 -- Check_Prefixed_Call --
3367 -------------------------
3376 begin
3377 -- Check whether the call is a prefixed call, with or without
3378 -- additional actuals.
3381 or else
3387 then
3390 then
3391 -- Introduce dereference on object in prefix
3393 New_A :=
3401 then
3402 -- Introduce an implicit 'Access in prefix
3405 Error_Msg_NE
3421 ---------------------------------------
3422 -- Flag_Effectively_Volatile_Objects --
3423 ---------------------------------------
3427 -- Determine whether arbitrary node N denotes an effectively volatile
3428 -- object and if it does, emit an error.
3430 -----------------
3431 -- Flag_Object --
3432 -----------------
3437 begin
3438 -- Do not consider nested function calls because they have already
3439 -- been processed during their own resolution.
3451 then
3452 Error_Msg_N
3464 -- Start of processing for Flag_Effectively_Volatile_Objects
3466 begin
3470 --------------------
3471 -- Insert_Default --
3472 --------------------
3478 begin
3479 -- Missing argument in call, nothing to insert
3484 else
3485 -- Note that we do a full New_Copy_Tree, so that any associated
3486 -- Itypes are properly copied. This may not be needed any more,
3487 -- but it does no harm as a safety measure. Defaults of a generic
3488 -- formal may be out of bounds of the corresponding actual (see
3489 -- cc1311b) and an additional check may be required.
3491 Actval :=
3492 New_Copy_Tree
3497 -- Propagate dimension information, if any.
3503 then
3509 then
3512 then
3513 -- If default is a real literal, do not introduce a
3514 -- conversion whose effect may depend on the run-time
3515 -- size of universal real.
3519 else
3530 -- Resolve aggregates with their base type, to avoid scope
3531 -- anomalies: the subtype was first built in the subprogram
3532 -- declaration, and the current call may be nested.
3536 else
3540 else
3543 -- See note above concerning aggregates
3547 then
3550 -- Resolve entities with their own type, which may differ from
3551 -- the type of a reference in a generic context (the view
3552 -- swapping mechanism did not anticipate the re-analysis of
3553 -- default values in calls).
3558 else
3563 -- If default is a tag indeterminate function call, propagate tag
3564 -- to obtain proper dispatching.
3568 then
3573 -- If the default expression raises constraint error, then just
3574 -- silently replace it with an N_Raise_Constraint_Error node, since
3575 -- we already gave the warning on the subprogram spec. If node is
3576 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3577 -- the warnings removal machinery.
3581 then
3590 Assoc :=
3595 -- Case of insertion is first named actual
3599 then
3606 else
3610 else
3614 -- Case of insertion is not first named actual
3616 else
3617 Set_Next_Named_Actual
3629 -------------------
3630 -- Same_Ancestor --
3631 -------------------
3637 begin
3640 then
3646 then
3653 --------------------------
3654 -- Static_Concatenation --
3655 --------------------------
3658 begin
3665 -- Concatenation is static when both operands are static and
3666 -- the concatenation operator is a predefined one.
3669 and then
3671 and then
3676 declare
3678 begin
3681 and then
3685 else
3691 -- Start of processing for Resolve_Actuals
3693 begin
3694 Check_Argument_Order;
3698 and then In_Instance
3701 then
3703 else
3708 Check_Prefixed_Call;
3722 -- If we have an error in any actual or formal, indicated by a type
3723 -- of Any_Type, then abandon resolution attempt, and set result type
3724 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3725 -- type is imposed from context.
3729 then
3736 -- Case where actual is present
3738 -- If the actual is an entity, generate a reference to it now. We
3739 -- do this before the actual is resolved, because a formal of some
3740 -- protected subprogram, or a task discriminant, will be rewritten
3741 -- during expansion, and the source entity reference may be lost.
3746 then
3752 then
3759 -- RM 6.4.1(12): For an out parameter that is passed by
3760 -- copy, the formal parameter object is created, and:
3762 -- * For an access type, the formal parameter is initialized
3763 -- from the value of the actual, without checking that the
3764 -- value satisfies any constraint, any predicate, or any
3765 -- exclusion of the null value.
3767 -- * For a scalar type that has the Default_Value aspect
3768 -- specified, the formal parameter is initialized from the
3769 -- value of the actual, without checking that the value
3770 -- satisfies any constraint or any predicate.
3771 -- I do not understand why this case is included??? this is
3772 -- not a case where an OUT parameter is treated as IN OUT.
3774 -- * For a composite type with discriminants or that has
3775 -- implicit initial values for any subcomponents, the
3776 -- behavior is as for an in out parameter passed by copy.
3778 -- Hence for these cases we generate the read reference now
3779 -- (the write reference will be generated later by
3780 -- Note_Possible_Modification).
3783 and then
3785 or else
3787 and then
3789 or else
3792 or else Is_Partially_Initialized_Type
3794 then
3804 then
3805 -- If style checking mode on, check match of formal name
3813 -- If the formal is Out or In_Out, do not resolve and expand the
3814 -- conversion, because it is subsequently expanded into explicit
3815 -- temporaries and assignments. However, the object of the
3816 -- conversion can be resolved. An exception is the case of tagged
3817 -- type conversion with a class-wide actual. In that case we want
3818 -- the tag check to occur and no temporary will be needed (no
3819 -- representation change can occur) and the parameter is passed by
3820 -- reference, so we go ahead and resolve the type conversion.
3821 -- Another exception is the case of reference to component or
3822 -- subcomponent of a bit-packed array, in which case we want to
3823 -- defer expansion to the point the in and out assignments are
3824 -- performed.
3829 then
3832 then
3833 -- In a view conversion, the conversion must be legal in
3834 -- both directions, and thus both component types must be
3835 -- aliased, or neither (4.6 (8)).
3837 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3838 -- the privacy requirement should not apply to generic
3839 -- types, and should be checked in an instance. ARG query
3840 -- is in order ???
3844 then
3845 Error_Msg_N
3849 -- Comment here??? what set of cases???
3851 elsif
3853 then
3854 -- Check view conv between unrelated by ref array types
3858 then
3859 Error_Msg_N
3863 -- In Ada 2005 mode, check view conversion component
3864 -- type cannot be private, tagged, or volatile. Note
3865 -- that we only apply this to source conversions. The
3866 -- generated code can contain conversions which are
3867 -- not subject to this test, and we cannot extract the
3868 -- component type in such cases since it is not present.
3872 then
3873 declare
3875 Component_Type
3877 begin
3882 then
3883 Error_Msg_N
3894 -- Resolve expression if conversion is all OK
3899 then
3903 -- If the actual is a function call that returns a limited
3904 -- unconstrained object that needs finalization, create a
3905 -- transient scope for it, so that it can receive the proper
3906 -- finalization list.
3911 and then Expander_Active
3913 then
3917 -- A small optimization: if one of the actuals is a concatenation
3918 -- create a block around a procedure call to recover stack space.
3919 -- This alleviates stack usage when several procedure calls in
3920 -- the same statement list use concatenation. We do not perform
3921 -- this wrapping for code statements, where the argument is a
3922 -- static string, and we want to preserve warnings involving
3923 -- sequences of such statements.
3927 and then Expander_Active
3928 and then
3932 then
3936 else
3940 and then
3943 then
3944 Error_Msg_N
3957 -- (Ada 2005: AI-251): If the actual is an allocator whose
3958 -- directly designated type is a class-wide interface, we build
3959 -- an anonymous access type to use it as the type of the
3960 -- allocator. Later, when the subprogram call is expanded, if
3961 -- the interface has a secondary dispatch table the expander
3962 -- will add a type conversion to force the correct displacement
3963 -- of the pointer.
3966 declare
3972 begin
3975 then
3978 Set_Directly_Designated_Type
3983 -- Ada 2005, AI-162:If the actual is an allocator, the
3984 -- innermost enclosing statement is the master of the
3985 -- created object. This needs to be done with expansion
3986 -- enabled only, otherwise the transient scope will not
3987 -- be removed in the expansion of the wrapped construct.
3990 and then Expander_Active
3991 then
4001 -- (Ada 2005): The call may be to a primitive operation of a
4002 -- tagged synchronized type, declared outside of the type. In
4003 -- this case the controlling actual must be converted to its
4004 -- corresponding record type, which is the formal type. The
4005 -- actual may be a subtype, either because of a constraint or
4006 -- because it is a generic actual, so use base type to locate
4007 -- concurrent type.
4014 then
4015 -- If the actual is overloaded, look for an interpretation
4016 -- that has a synchronized type.
4021 else
4022 declare
4026 begin
4031 then
4041 declare
4044 begin
4047 else
4051 -- Tagged synchronized type (case 1): the actual is a
4052 -- concurrent type.
4056 then
4058 Unchecked_Convert_To
4062 -- Tagged synchronized type (case 2): the formal is a
4063 -- concurrent type.
4066 and then Present
4071 then
4074 -- Common case
4076 else
4081 -- Not a synchronized operation
4083 else
4091 -- An actual cannot be an untagged formal incomplete type
4096 then
4097 Error_Msg_N
4103 N_Procedure_Call_Statement)
4104 then
4105 -- In formal mode, check that actual parameters matching
4106 -- formals of tagged types are objects (or ancestor type
4107 -- conversions of objects), not general expressions.
4114 declare
4119 begin
4121 Check_SPARK_05_Restriction
4124 -- In formal mode, the only view conversions are those
4125 -- involving ancestor conversion of an extended type.
4127 elsif not
4133 then
4134 if Ekind_In
4136 then
4137 Check_SPARK_05_Restriction
4140 else
4141 Check_SPARK_05_Restriction
4145 else
4150 else
4154 -- In formal mode, the only view conversions are those
4155 -- involving ancestor conversion of an extended type.
4159 then
4160 Check_SPARK_05_Restriction
4166 -- has warnings suppressed, then we reset Never_Set_In_Source for
4167 -- the calling entity. The reason for this is to catch cases like
4168 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4169 -- uses trickery to modify an IN parameter.
4176 then
4180 -- Perform error checks for IN and IN OUT parameters
4184 -- Check unset reference. For scalar parameters, it is clearly
4185 -- wrong to pass an uninitialized value as either an IN or
4186 -- IN-OUT parameter. For composites, it is also clearly an
4187 -- error to pass a completely uninitialized value as an IN
4188 -- parameter, but the case of IN OUT is trickier. We prefer
4189 -- not to give a warning here. For example, suppose there is
4190 -- a routine that sets some component of a record to False.
4191 -- It is perfectly reasonable to make this IN-OUT and allow
4192 -- either initialized or uninitialized records to be passed
4193 -- in this case.
4195 -- For partially initialized composite values, we also avoid
4196 -- warnings, since it is quite likely that we are passing a
4197 -- partially initialized value and only the initialized fields
4198 -- will in fact be read in the subprogram.
4203 then
4207 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4208 -- actual to a nested call, since this constitutes a reading of
4209 -- the parameter, which is not allowed.
4214 then
4219 -- In -gnatd.q mode, forget that a given array is constant when
4220 -- it is passed as an IN parameter to a foreign-convention
4221 -- subprogram. This is in case the subprogram evilly modifies the
4222 -- object. Of course, correct code would use IN OUT.
4224 if Debug_Flag_Dot_Q
4230 then
4234 -- Case of OUT or IN OUT parameter
4238 -- For an Out parameter, check for useless assignment. Note
4239 -- that we can't set Last_Assignment this early, because we may
4240 -- kill current values in Resolve_Call, and that call would
4241 -- clobber the Last_Assignment field.
4243 -- Note: call Warn_On_Useless_Assignment before doing the check
4244 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4245 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4246 -- reflects the last assignment, not this one.
4253 then
4258 -- Validate the form of the actual. Note that the call to
4259 -- Is_OK_Variable_For_Out_Formal generates the required
4260 -- reference in this case.
4262 -- A call to an initialization procedure for an aggregate
4263 -- component may initialize a nested component of a constant
4264 -- designated object. In this context the object is variable.
4268 then
4274 then
4275 Error_Msg_N
4280 Error_Msg_N
4287 -- What's the following about???
4291 else
4292 Kill_All_Checks;
4301 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4305 -- Apply predicate tests except in certain special cases. Note
4306 -- that it might be more consistent to apply these only when
4307 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4308 -- for the outbound predicate tests ??? In any case indicate
4309 -- the function being called, for better warnings if the call
4310 -- leads to an infinite recursion.
4316 -- Apply required constraint checks
4318 -- Gigi looks at the check flag and uses the appropriate types.
4319 -- For now since one flag is used there is an optimization
4320 -- which might not be done in the IN OUT case since Gigi does
4321 -- not do any analysis. More thought required about this ???
4323 -- In fact is this comment obsolete??? doesn't the expander now
4324 -- generate all these tests anyway???
4337 then
4340 -- For view conversions of a discriminated object, apply
4341 -- check to object itself, the conversion alreay has the
4342 -- proper type.
4346 then
4353 then
4359 then
4362 else
4366 -- Ada 2005 (AI-231): Note that the controlling parameter case
4367 -- already existed in Ada 95, which is partially checked
4368 -- elsewhere (see Checks), and we don't want the warning
4369 -- message to differ.
4374 then
4376 Apply_Compile_Time_Constraint_Error
4382 Apply_Compile_Time_Constraint_Error
4391 -- Checks for OUT parameters and IN OUT parameters
4395 -- If there is a type conversion, make sure the return value
4396 -- meets the constraints of the variable before the conversion.
4400 Apply_Scalar_Range_Check
4403 -- In addition, the returned value of the parameter must
4404 -- satisfy the bounds of the object type (see comment
4405 -- below).
4409 else
4410 Apply_Range_Check
4414 -- If no conversion, apply scalar range checks and length check
4415 -- based on the subtype of the actual (NOT that of the formal).
4416 -- This indicates that the check takes place on return from the
4417 -- call. During expansion the required constraint checks are
4418 -- inserted. In GNATprove mode, in the absence of expansion,
4419 -- the flag indicates that the returned value is valid.
4421 else
4427 then
4429 else
4434 -- Note: we do not apply the predicate checks for the case of
4435 -- OUT and IN OUT parameters. They are instead applied in the
4436 -- Expand_Actuals routine in Exp_Ch6.
4439 -- An actual associated with an access parameter is implicitly
4440 -- converted to the anonymous access type of the formal and must
4441 -- satisfy the legality checks for access conversions.
4445 Error_Msg_N
4449 -- If the actual is an access selected component of a variable,
4450 -- the call may modify its designated object. It is reasonable
4451 -- to treat this as a potential modification of the enclosing
4452 -- record, to prevent spurious warnings that it should be
4453 -- declared as a constant, because intuitively programmers
4454 -- regard the designated subcomponent as part of the record.
4459 then
4464 -- Check bad case of atomic/volatile argument (RM C.6(12))
4468 then
4471 then
4472 Error_Msg_NE
4478 then
4479 Error_Msg_NE
4485 -- Check that subprograms don't have improper controlling
4486 -- arguments (RM 3.9.2 (9)).
4488 -- A primitive operation may have an access parameter of an
4489 -- incomplete tagged type, but a dispatching call is illegal
4490 -- if the type is still incomplete.
4496 declare
4498 begin
4502 then
4503 Error_Msg_NE
4514 -- Apply legality rule 3.9.2 (9/1)
4519 and then not In_Instance
4520 then
4525 Error_Msg_NE
4529 -- Apply the checks described in 3.10.2(27): if the context is a
4530 -- specific access-to-object, the actual cannot be class-wide.
4531 -- Use base type to exclude access_to_subprogram cases.
4538 and then
4543 -- Disable these checks for call to imported C++ subprograms
4545 and then not
4549 then
4550 Error_Msg_N
4555 Error_Msg_NE
4560 Check_Aliased_Parameter;
4564 -- If it is a named association, treat the selector_name as a
4565 -- proper identifier, and mark the corresponding entity.
4569 -- Ignore reference in SPARK mode, as it refers to an entity not
4570 -- in scope at the point of reference, so the reference should
4571 -- be ignored for computing effects of subprograms.
4573 and then not GNATprove_Mode
4574 then
4575 -- If subprogram is overridden, use name of formal that
4576 -- is being called.
4582 else
4596 -- The following checks are only relevant when SPARK_Mode is on as
4597 -- they are not standard Ada legality rule. Internally generated
4598 -- temporaries are ignored.
4602 -- An effectively volatile object may act as an actual when the
4603 -- corresponding formal is of a non-scalar effectively volatile
4604 -- type (SPARK RM 7.1.3(11)).
4608 then
4611 -- An effectively volatile object may act as an actual in a
4612 -- call to an instance of Unchecked_Conversion.
4613 -- (SPARK RM 7.1.3(11)).
4618 -- The actual denotes an object
4621 Error_Msg_N
4625 -- Otherwise the actual denotes an expression. Inspect the
4626 -- expression and flag each effectively volatile object with
4627 -- enabled property Async_Writers or Effective_Reads as illegal
4628 -- because it apprears within an interfering context. Note that
4629 -- this is usually done in Resolve_Entity_Name, but when the
4630 -- effectively volatile object appears as an actual in a call,
4631 -- the call must be resolved first.
4633 else
4637 -- An effectively volatile variable cannot act as an actual
4638 -- parameter in a procedure call when the variable has enabled
4639 -- property Effective_Reads and the corresponding formal is of
4640 -- mode IN (SPARK RM 7.1.3(10)).
4645 then
4651 then
4652 Error_Msg_NE
4663 -- A formal parameter of a specific tagged type whose related
4664 -- subprogram is subject to pragma Extensions_Visible with value
4665 -- "False" cannot act as an actual in a subprogram with value
4666 -- "True" (SPARK RM 6.1.7(3)).
4670 Extensions_Visible_True
4671 then
4672 Error_Msg_N
4675 Error_Msg_NE
4679 -- The actual parameter of a Ghost subprogram whose formal is of
4680 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4688 then
4689 Error_Msg_NE
4695 else
4702 -- Case where actual is not present
4704 else
4705 Insert_Default;
4716 -----------------------
4717 -- Resolve_Allocator --
4718 -----------------------
4730 procedure Check_Allocator_Discrim_Accessibility
4733 -- Check that accessibility level associated with an access discriminant
4734 -- initialized in an allocator by the expression Disc_Exp is not deeper
4735 -- than the level of the allocator type Alloc_Typ. An error message is
4736 -- issued if this condition is violated. Specialized checks are done for
4737 -- the cases of a constraint expression which is an access attribute or
4738 -- an access discriminant.
4741 -- If the allocator is an actual in a call, it is allowed to be class-
4742 -- wide when the context is not because it is a controlling actual.
4744 -------------------------------------------
4745 -- Check_Allocator_Discrim_Accessibility --
4746 -------------------------------------------
4748 procedure Check_Allocator_Discrim_Accessibility
4751 is
4752 begin
4755 then
4756 Error_Msg_N
4759 -- When the expression is an Access attribute the level of the prefix
4760 -- object must not be deeper than that of the allocator's type.
4764 Attribute_Access
4767 then
4768 Error_Msg_N
4770 Disc_Exp);
4772 -- When the expression is an access discriminant the check is against
4773 -- the level of the prefix object.
4779 then
4780 Error_Msg_N
4782 Disc_Exp);
4784 -- All other cases are legal
4786 else
4791 ----------------------------
4792 -- In_Dispatching_Context --
4793 ----------------------------
4798 begin
4804 -- Start of processing for Resolve_Allocator
4806 begin
4807 -- Replace general access with specific type
4817 -- For qualified expression, resolve the expression using the given
4818 -- subtype (nothing to do for type mark, subtype indication)
4823 and then not In_Dispatching_Context
4824 then
4825 Error_Msg_N
4833 -- Allocators generated by the build-in-place expansion mechanism
4834 -- are explicitly marked as coming from source but do not need to be
4835 -- checked for limited initialization. To exclude this case, ensure
4836 -- that the parent of the allocator is a source node.
4837 -- The return statement constructed for an Expression_Function does
4838 -- not come from source but requires a limited check.
4842 and then
4844 or else
4846 and then Nkind
4849 and then not In_Instance_Body
4850 then
4853 Error_Msg_N
4856 else
4857 Error_Msg_N
4865 -- A qualified expression requires an exact match of the type. Class-
4866 -- wide matching is not allowed.
4871 then
4875 -- Calls to build-in-place functions are not currently supported in
4876 -- allocators for access types associated with a simple storage pool.
4877 -- Supporting such allocators may require passing additional implicit
4878 -- parameters to build-in-place functions (or a significant revision
4879 -- of the current b-i-p implementation to unify the handling for
4880 -- multiple kinds of storage pools). ???
4884 then
4885 declare
4888 begin
4890 and then
4891 Present (Get_Rep_Pragma
4893 then
4894 Error_Msg_N
4901 -- A special accessibility check is needed for allocators that
4902 -- constrain access discriminants. The level of the type of the
4903 -- expression used to constrain an access discriminant cannot be
4904 -- deeper than the type of the allocator (in contrast to access
4905 -- parameters, where the level of the actual can be arbitrary).
4907 -- We can't use Valid_Conversion to perform this check because in
4908 -- general the type of the allocator is unrelated to the type of
4909 -- the access discriminant.
4913 then
4920 then
4923 -- Get the first component expression of the aggregate
4933 else
4937 else
4956 else
4961 else
4970 -- For a subtype mark or subtype indication, freeze the subtype
4972 else
4976 Error_Msg_N
4980 -- A special accessibility check is needed for allocators that
4981 -- constrain access discriminants. The level of the type of the
4982 -- expression used to constrain an access discriminant cannot be
4983 -- deeper than the type of the allocator (in contrast to access
4984 -- parameters, where the level of the actual can be arbitrary).
4985 -- We can't use Valid_Conversion to perform this check because
4986 -- in general the type of the allocator is unrelated to the type
4987 -- of the access discriminant.
4992 then
5002 else
5016 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5017 -- check that the level of the type of the created object is not deeper
5018 -- than the level of the allocator's access type, since extensions can
5019 -- now occur at deeper levels than their ancestor types. This is a
5020 -- static accessibility level check; a run-time check is also needed in
5021 -- the case of an initialized allocator with a class-wide argument (see
5022 -- Expand_Allocator_Expression).
5026 then
5027 declare
5030 begin
5035 else
5041 then
5044 Error_Msg_N
5053 -- Do not apply Ada 2005 accessibility checks on a class-wide
5054 -- allocator if the type given in the allocator is a formal
5055 -- type. A run-time check will be performed in the instance.
5065 -- Check for allocation from an empty storage pool
5070 -- If the context is an unchecked conversion, as may happen within an
5071 -- inlined subprogram, the allocator is being resolved with its own
5072 -- anonymous type. In that case, if the target type has a specific
5073 -- storage pool, it must be inherited explicitly by the allocator type.
5077 then
5078 Set_Associated_Storage_Pool
5086 -- Check that an allocator with task parts isn't for a nested access
5087 -- type when restriction No_Task_Hierarchy applies.
5091 then
5095 -- An illegal allocator may be rewritten as a raise Program_Error
5096 -- statement.
5100 -- An anonymous access discriminant is the definition of a
5101 -- coextension.
5105 N_Discriminant_Specification
5106 then
5107 declare
5111 begin
5114 -- Ada 2012 AI05-0052: If the designated type of the allocator
5115 -- is limited, then the allocator shall not be used to define
5116 -- the value of an access discriminant unless the discriminated
5117 -- type is immutably limited.
5122 then
5123 Error_Msg_N
5129 -- Avoid marking an allocator as a dynamic coextension if it is
5130 -- within a static construct.
5136 -- Cleanup for potential static coextensions
5138 else
5144 -- Report a simple error: if the designated object is a local task,
5145 -- its body has not been seen yet, and its activation will fail an
5146 -- elaboration check.
5153 then
5159 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5160 -- type with a task component on a subpool. This action must raise
5161 -- Program_Error at runtime.
5167 then
5179 ---------------------------
5180 -- Resolve_Arithmetic_Op --
5181 ---------------------------
5183 -- Used for resolving all arithmetic operators except exponentiation
5194 -- We do the resolution using the base type, because intermediate values
5195 -- in expressions always are of the base type, not a subtype of it.
5198 -- Returns True if N is in a context that expects "any real type"
5201 -- Return True iff given type is Integer or universal real/integer
5204 -- Choose type of integer literal in fixed-point operation to conform
5205 -- to available fixed-point type. T is the type of the other operand,
5206 -- which is needed to determine the expected type of N.
5209 -- Set operand type to T if universal
5211 -------------------------------
5212 -- Expected_Type_Is_Any_Real --
5213 -------------------------------
5216 begin
5217 -- N is the expression after "delta" in a fixed_point_definition;
5218 -- see RM-3.5.9(6):
5221 N_Decimal_Fixed_Point_Definition,
5223 -- N is one of the bounds in a real_range_specification;
5224 -- see RM-3.5.7(5):
5226 N_Real_Range_Specification,
5228 -- N is the expression of a delta_constraint;
5229 -- see RM-J.3(3):
5231 N_Delta_Constraint);
5234 -----------------------------
5235 -- Is_Integer_Or_Universal --
5236 -----------------------------
5243 begin
5249 else
5255 then
5266 ----------------------------
5267 -- Set_Mixed_Mode_Operand --
5268 ----------------------------
5274 begin
5277 -- A universal integer literal is resolved as standard integer
5278 -- except in the case of a fixed-point result, where we leave it
5279 -- as universal (to be handled by Exp_Fixd later on)
5283 else
5291 then
5292 -- A universal real can appear in a fixed-type context. We resolve
5293 -- the literal with that context, even though this might raise an
5294 -- exception prematurely (the other operand may be zero).
5301 then
5302 -- Integer arg in mixed-mode operation. Resolve with universal
5303 -- type, in case preference rule must be applied.
5309 then
5310 -- Not a mixed-mode operation, resolve with context
5316 -- N may itself be a mixed-mode operation, so use context type
5323 then
5324 -- Must be (fixed * fixed) operation, operand must have one
5325 -- compatible interpretation.
5332 then
5333 -- C * F(X) in a fixed context, where C is a real literal or a
5334 -- fixed-point expression. F must have either a fixed type
5335 -- interpretation or an integer interpretation, but not both.
5342 else
5349 else
5357 -- Reanalyze the literal with the fixed type of the context. If
5358 -- context is Universal_Fixed, we are within a conversion, leave
5359 -- the literal as a universal real because there is no usable
5360 -- fixed type, and the target of the conversion plays no role in
5361 -- the resolution.
5363 declare
5367 begin
5370 else
5376 then
5378 else
5386 -- A universal real conditional expression can appear in a fixed-type
5387 -- context and must be resolved with that context to facilitate the
5388 -- code generation to the backend.
5393 then
5396 else
5401 ----------------------
5402 -- Set_Operand_Type --
5403 ----------------------
5406 begin
5409 then
5414 -- Start of processing for Resolve_Arithmetic_Op
5416 begin
5421 then
5425 -- Special-case for mixed-mode universal expressions or fixed point type
5426 -- operation: each argument is resolved separately. The same treatment
5427 -- is required if one of the operands of a fixed point operation is
5428 -- universal real, since in this case we don't do a conversion to a
5429 -- specific fixed-point type (instead the expander handles the case).
5431 -- Set the type of the node to its universal interpretation because
5432 -- legality checks on an exponentiation operand need the context.
5437 then
5448 or else
5451 then
5456 -- If context is a fixed type and one operand is integer, the other
5457 -- is resolved with the type of the context.
5462 then
5469 then
5473 -- If both operands are universal and the context is a floating
5474 -- point type, the operands are resolved to the type of the context.
5480 else
5485 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5486 -- multiplying operators from being used when the expected type is
5487 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5488 -- some cases where the expected type is actually Any_Real;
5489 -- Expected_Type_Is_Any_Real takes care of that case.
5493 then
5497 N_Unchecked_Type_Conversion)
5498 then
5505 else
5508 and then not
5510 N_Unchecked_Type_Conversion)
5511 then
5512 Error_Msg_N
5517 -- The expected type is "any real type" in contexts like
5519 -- type T is delta <universal_fixed-expression> ...
5521 -- in which case we need to set the type to Universal_Real
5522 -- so that static expression evaluation will work properly.
5526 else
5536 then
5541 -- If no previous errors, this is only possible if one operand is
5542 -- overloaded and the context is universal. Resolve as such.
5547 else
5549 and then
5551 then
5555 -- If the context is Universal_Fixed and the operands are also
5556 -- universal fixed, this is an error, unless there is only one
5557 -- applicable fixed_point type (usually Duration).
5565 else
5570 else
5575 -- If one of the arguments was resolved to a non-universal type.
5576 -- label the result of the operation itself with the same type.
5577 -- Do the same for the universal argument, if any.
5589 -- In SPARK, a multiplication or division with operands of fixed point
5590 -- types must be qualified or explicitly converted to identify the
5591 -- result type.
5596 and then
5598 then
5599 Check_SPARK_05_Restriction
5603 -- Set overflow and division checking bit
5610 -- Give warning if explicit division by zero
5614 then
5620 or else
5623 then
5624 -- Specialize the warning message according to the operation.
5625 -- When SPARK_Mode is On, force a warning instead of an error
5626 -- in that case, as this likely corresponds to deactivated
5627 -- code. The following warnings are for the case
5632 -- For division, we have two cases, for float division
5633 -- of an unconstrained float type, on a machine where
5634 -- Machine_Overflows is false, we don't get an exception
5635 -- at run-time, but rather an infinity or Nan. The Nan
5636 -- case is pretty obscure, so just warn about infinities.
5640 and then not Machine_Overflows_On_Target
5641 then
5642 Error_Msg_N
5646 -- For all other cases, we get a Constraint_Error
5648 else
5649 Apply_Compile_Time_Constraint_Error
5656 Apply_Compile_Time_Constraint_Error
5662 Apply_Compile_Time_Constraint_Error
5667 -- Division by zero can only happen with division, rem,
5668 -- and mod operations.
5674 -- In GNATprove mode, we enable the division check so that
5675 -- GNATprove will issue a message if it cannot be proved.
5681 -- Otherwise just set the flag to check at run time
5683 else
5688 -- If Restriction No_Implicit_Conditionals is active, then it is
5689 -- violated if either operand can be negative for mod, or for rem
5690 -- if both operands can be negative.
5694 then
5695 declare
5702 -- Set if corresponding operand might be negative
5704 begin
5705 Determine_Range
5709 Determine_Range
5713 -- Check if we will be generating conditionals. There are two
5714 -- cases where that can happen, first for REM, the only case
5715 -- is largest negative integer mod -1, where the division can
5716 -- overflow, but we still have to give the right result. The
5717 -- front end generates a test for this annoying case. Here we
5718 -- just test if both operands can be negative (that's what the
5719 -- expander does, so we match its logic here).
5721 -- The second case is mod where either operand can be negative.
5722 -- In this case, the back end has to generate additional tests.
5725 or else
5727 then
5738 ------------------
5739 -- Resolve_Call --
5740 ------------------
5743 function Same_Or_Aliased_Subprograms
5746 -- Returns True if the subprogram entity S is the same as E or else
5747 -- S is an alias of E.
5749 ---------------------------------
5750 -- Same_Or_Aliased_Subprograms --
5751 ---------------------------------
5753 function Same_Or_Aliased_Subprograms
5756 is
5758 begin
5762 -- Local variables
5776 -- Start of processing for Resolve_Call
5778 begin
5779 -- Preserve relevant elaboration-related attributes of the context which
5780 -- are no longer available or very expensive to recompute once analysis,
5781 -- resolution, and expansion are over.
5783 Mark_Elaboration_Attributes
5788 -- The context imposes a unique interpretation with type Typ on a
5789 -- procedure or function call. Find the entity of the subprogram that
5790 -- yields the expected type, and propagate the corresponding formal
5791 -- constraints on the actuals. The caller has established that an
5792 -- interpretation exists, and emitted an error if not unique.
5794 -- First deal with the case of a call to an access-to-subprogram,
5795 -- dereference made explicit in Analyze_Call.
5801 else
5802 -- Find the interpretation whose type (a subprogram type) has a
5803 -- return type that is compatible with the context. Analysis of
5804 -- the node has established that one exists.
5823 -- If the prefix is not an entity, then resolve it
5829 -- For an indirect call, we always invalidate checks, since we do not
5830 -- know whether the subprogram is local or global. Yes we could do
5831 -- better here, e.g. by knowing that there are no local subprograms,
5832 -- but it does not seem worth the effort. Similarly, we kill all
5833 -- knowledge of current constant values.
5835 Kill_Current_Values;
5837 -- If this is a procedure call which is really an entry call, do
5838 -- the conversion of the procedure call to an entry call. Protected
5839 -- operations use the same circuitry because the name in the call
5840 -- can be an arbitrary expression with special resolution rules.
5845 then
5848 -- Annotate the tree by creating a call marker in case the original
5849 -- call is transformed by expansion. The call marker is automatically
5850 -- saved for later examination by the ABE Processing phase.
5854 -- Kill checks and constant values, as above for indirect case
5855 -- Who knows what happens when another task is activated?
5857 Kill_Current_Values;
5860 -- Normal subprogram call with name established in Resolve
5866 -- Otherwise we must have the case of an overloaded call
5868 else
5871 -- Initialize Nam to prevent warning (we know it will be assigned
5872 -- in the loop below, but the compiler does not know that).
5892 then
5893 -- The prefix is a parameterless function call that returns an access
5894 -- to subprogram. If parameters are present in the current call, add
5895 -- add an explicit dereference. We use the base type here because
5896 -- within an instance these may be subtypes.
5898 -- The dereference is added either in Analyze_Call or here. Should
5899 -- be consolidated ???
5908 -- Check that a call to Current_Task does not occur in an entry body
5911 declare
5914 begin
5916 loop
5919 -- Exclude calls that occur within the default of a formal
5920 -- parameter of the entry, since those are evaluated outside
5921 -- of the body.
5928 then
5931 Error_Msg_NE
5945 -- Check that a procedure call does not occur in the context of the
5946 -- entry call statement of a conditional or timed entry call. Note that
5947 -- the case of a call to a subprogram renaming of an entry will also be
5948 -- rejected. The test for N not being an N_Entry_Call_Statement is
5949 -- defensive, covering the possibility that the processing of entry
5950 -- calls might reach this point due to later modifications of the code
5951 -- above.
5956 then
5960 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5961 -- for a procedure_or_entry_call, the procedure_name or
5962 -- procedure_prefix of the procedure_call_statement shall denote
5963 -- an entry renamed by a procedure, or (a view of) a primitive
5964 -- subprogram of a limited interface whose first parameter is
5965 -- a controlling parameter.
5970 then
5971 Error_Msg_N
5976 -- If the SPARK_05 restriction is active, we are not allowed
5977 -- to have a call to a subprogram before we see its completion.
5982 -- Don't flag strange internal calls
5987 -- Only flag calls in extended main source
5992 -- Exclude enumeration literals from this processing
5995 then
5996 Check_SPARK_05_Restriction
6000 -- Check that this is not a call to a protected procedure or entry from
6001 -- within a protected function.
6005 -- Freeze the subprogram name if not in a spec-expression. Note that
6006 -- we freeze procedure calls as well as function calls. Procedure calls
6007 -- are not frozen according to the rules (RM 13.14(14)) because it is
6008 -- impossible to have a procedure call to a non-frozen procedure in
6009 -- pure Ada, but in the code that we generate in the expander, this
6010 -- rule needs extending because we can generate procedure calls that
6011 -- need freezing.
6013 -- In Ada 2012, expression functions may be called within pre/post
6014 -- conditions of subsequent functions or expression functions. Such
6015 -- calls do not freeze when they appear within generated bodies,
6016 -- (including the body of another expression function) which would
6017 -- place the freeze node in the wrong scope. An expression function
6018 -- is frozen in the usual fashion, by the appearance of a real body,
6019 -- or at the end of a declarative part.
6022 and then not In_Spec_Expression
6024 and then
6027 then
6031 -- For a predefined operator, the type of the result is the type imposed
6032 -- by context, except for a predefined operation on universal fixed.
6033 -- Otherwise The type of the call is the type returned by the subprogram
6034 -- being called.
6041 -- If the subprogram returns an array type, and the context requires the
6042 -- component type of that array type, the node is really an indexing of
6043 -- the parameterless call. Resolve as such. A pathological case occurs
6044 -- when the type of the component is an access to the array type. In
6045 -- this case the call is truly ambiguous. If the call is to an intrinsic
6046 -- subprogram, it can't be an indexed component. This check is necessary
6047 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6048 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6049 -- pointers to the same array), the compiler gets confused and does an
6050 -- infinite recursion.
6053 and then
6056 or else
6059 and then
6062 then
6063 declare
6068 begin
6071 then
6072 Error_Msg_N
6074 else
6077 -- The called entity may be an explicit dereference, in which
6078 -- case there is no entity to set.
6086 or else
6088 and then
6090 then
6093 -- Indexed call to a parameterless function
6095 Index_Node :=
6097 Prefix =>
6100 else
6101 -- An Ada 2005 prefixed call to a primitive operation
6102 -- whose first parameter is the prefix. This prefix was
6103 -- prepended to the parameter list, which is actually a
6104 -- list of indexes. Remove the prefix in order to build
6105 -- the proper indexed component.
6107 Index_Node :=
6109 Prefix =>
6112 Parameter_Associations =>
6113 New_List
6118 -- Preserve the parenthesis count of the node
6122 -- Since we are correcting a node classification error made
6123 -- by the parser, we call Replace rather than Rewrite.
6131 -- Annotate the tree by creating a call marker in case
6132 -- the original call is transformed by expansion. The call
6133 -- marker is automatically saved for later examination by
6134 -- the ABE Processing phase.
6143 else
6144 -- If the called function is not declared in the main unit and it
6145 -- returns the limited view of type then use the available view (as
6146 -- is done in Try_Object_Operation) to prevent back-end confusion;
6147 -- for the function entity itself. The call must appear in a context
6148 -- where the nonlimited view is available. If the function entity is
6149 -- in the extended main unit then no action is needed, because the
6150 -- back end handles this case. In either case the type of the call
6151 -- is the nonlimited view.
6155 then
6162 else
6167 -- In the case where the call is to an overloaded subprogram, Analyze
6168 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6169 -- such a case Normalize_Actuals needs to be called once more to order
6170 -- the actuals correctly. Otherwise the call will have the ordering
6171 -- given by the last overloaded subprogram whether this is the correct
6172 -- one being called or not.
6179 -- In any case, call is fully resolved now. Reset Overload flag, to
6180 -- prevent subsequent overload resolution if node is analyzed again
6185 -- A Ghost entity must appear in a specific context
6191 -- If we are calling the current subprogram from immediately within its
6192 -- body, then that is the case where we can sometimes detect cases of
6193 -- infinite recursion statically. Do not try this in case restriction
6194 -- No_Recursion is in effect anyway, and do it only for source calls.
6199 -- Check violation of SPARK_05 restriction which does not permit
6200 -- a subprogram body to contain a call to the subprogram directly.
6204 then
6205 Check_SPARK_05_Restriction
6209 -- Issue warning for possible infinite recursion in the absence
6210 -- of the No_Recursion restriction.
6215 then
6216 -- Here we detected and flagged an infinite recursion, so we do
6217 -- not need to test the case below for further warnings. Also we
6218 -- are all done if we now have a raise SE node.
6224 -- If call is to immediately containing subprogram, then check for
6225 -- the case of a possible run-time detectable infinite recursion.
6227 else
6231 -- Although in general case, recursion is not statically
6232 -- checkable, the case of calling an immediately containing
6233 -- subprogram is easy to catch.
6237 -- If the recursive call is to a parameterless subprogram,
6238 -- then even if we can't statically detect infinite
6239 -- recursion, this is pretty suspicious, and we output a
6240 -- warning. Furthermore, we will try later to detect some
6241 -- cases here at run time by expanding checking code (see
6242 -- Detect_Infinite_Recursion in package Exp_Ch6).
6244 -- If the recursive call is within a handler, do not emit a
6245 -- warning, because this is a common idiom: loop until input
6246 -- is correct, catch illegal input in handler and restart.
6252 then
6253 -- For the case of a procedure call. We give the message
6254 -- only if the call is the first statement in a sequence
6255 -- of statements, or if all previous statements are
6256 -- simple assignments. This is simply a heuristic to
6257 -- decrease false positives, without losing too many good
6258 -- warnings. The idea is that these previous statements
6259 -- may affect global variables the procedure depends on.
6260 -- We also exclude raise statements, that may arise from
6261 -- constraint checks and are probably unrelated to the
6262 -- intended control flow.
6266 then
6267 declare
6269 begin
6273 N_Raise_Constraint_Error)
6274 then
6283 -- Do not give warning if we are in a conditional context
6285 declare
6287 begin
6293 then
6298 -- Here warning is to be issued
6314 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6318 -- If subprogram name is a predefined operator, it was given in
6319 -- functional notation. Replace call node with operator node, so
6320 -- that actuals can be resolved appropriately.
6328 then
6334 -- Create a transient scope if the resulting type requires it
6336 -- There are several notable exceptions:
6338 -- a) In init procs, the transient scope overhead is not needed, and is
6339 -- even incorrect when the call is a nested initialization call for a
6340 -- component whose expansion may generate adjust calls. However, if the
6341 -- call is some other procedure call within an initialization procedure
6342 -- (for example a call to Create_Task in the init_proc of the task
6343 -- run-time record) a transient scope must be created around this call.
6345 -- b) Enumeration literal pseudo-calls need no transient scope
6347 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6348 -- functions) do not use the secondary stack even though the return
6349 -- type may be unconstrained.
6351 -- d) Calls to a build-in-place function, since such functions may
6352 -- allocate their result directly in a target object, and cases where
6353 -- the result does get allocated in the secondary stack are checked for
6354 -- within the specialized Exp_Ch6 procedures for expanding those
6355 -- build-in-place calls.
6357 -- e) Calls to inlinable expression functions do not use the secondary
6358 -- stack (since the call will be replaced by its returned object).
6360 -- f) If the subprogram is marked Inline_Always, then even if it returns
6361 -- an unconstrained type the call does not require use of the secondary
6362 -- stack. However, inlining will only take place if the body to inline
6363 -- is already present. It may not be available if e.g. the subprogram is
6364 -- declared in a child instance.
6366 -- If this is an initialization call for a type whose construction
6367 -- uses the secondary stack, and it is not a nested call to initialize
6368 -- a component, we do need to create a transient scope for it. We
6369 -- check for this by traversing the type in Check_Initialization_Call.
6375 then
6382 then
6385 elsif Expander_Active
6388 and then
6390 or else
6392 then
6395 -- If the call appears within the bounds of a loop, it will
6396 -- be rewritten and reanalyzed, nothing left to do here.
6403 and then not Within_Init_Proc
6404 then
6408 -- A protected function cannot be called within the definition of the
6409 -- enclosing protected type, unless it is part of a pre/postcondition
6410 -- on another protected operation. This may appear in the entry wrapper
6411 -- created for an entry with preconditions.
6416 and then not In_Spec_Expression
6418 then
6419 Error_Msg_NE
6423 -- Propagate interpretation to actuals, and add default expressions
6424 -- where needed.
6429 -- Overloaded literals are rewritten as function calls, for purpose of
6430 -- resolution. After resolution, we can replace the call with the
6431 -- literal itself.
6437 -- Avoid validation, since it is a static function call
6443 -- If the subprogram is not global, then kill all saved values and
6444 -- checks. This is a bit conservative, since in many cases we could do
6445 -- better, but it is not worth the effort. Similarly, we kill constant
6446 -- values. However we do not need to do this for internal entities
6447 -- (unless they are inherited user-defined subprograms), since they
6448 -- are not in the business of molesting local values.
6450 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6451 -- kill all checks and values for calls to global subprograms. This
6452 -- takes care of the case where an access to a local subprogram is
6453 -- taken, and could be passed directly or indirectly and then called
6454 -- from almost any context.
6456 -- Note: we do not do this step till after resolving the actuals. That
6457 -- way we still take advantage of the current value information while
6458 -- scanning the actuals.
6460 -- We suppress killing values if we are processing the nodes associated
6461 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6462 -- type kills all the values as part of analyzing the code that
6463 -- initializes the dispatch tables.
6467 or else Suppress_Value_Tracking_On_Call
6472 then
6473 Kill_Current_Values;
6476 -- If we are warning about unread OUT parameters, this is the place to
6477 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6478 -- after the above call to Kill_Current_Values (since that call clears
6479 -- the Last_Assignment field of all local variables).
6484 then
6485 declare
6489 begin
6499 then
6509 -- If the subprogram is a primitive operation, check whether or not
6510 -- it is a correct dispatching call.
6514 then
6519 and then not In_Instance
6520 then
6524 -- If this is a dispatching call, generate the appropriate reference,
6525 -- for better source navigation in GPS.
6529 then
6532 -- Normal case, not a dispatching call: generate a call reference
6534 else
6542 -- Check for violation of restriction No_Specific_Termination_Handlers
6543 -- and warn on a potentially blocking call to Abort_Task.
6547 or else
6549 then
6556 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6557 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6558 -- need to check the second argument to determine whether it is an
6559 -- absolute or relative timing event.
6564 then
6568 -- Issue an error for a call to an eliminated subprogram. This routine
6569 -- will not perform the check if the call appears within a default
6570 -- expression.
6574 -- In formal mode, the primitive operations of a tagged type or type
6575 -- extension do not include functions that return the tagged type.
6581 then
6585 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6586 -- class-wide and the call dispatches on result in a context that does
6587 -- not provide a tag, the call raises Program_Error.
6590 and then In_Instance
6595 then
6596 -- Verify that none of the formals are controlling
6598 declare
6602 begin
6624 -- Check for calling a function with OUT or IN OUT parameter when the
6625 -- calling context (us right now) is not Ada 2012, so does not allow
6626 -- OUT or IN OUT parameters in function calls. Functions declared in
6627 -- a predefined unit are OK, as they may be called indirectly from a
6628 -- user-declared instantiation.
6634 then
6639 -- Check the dimensions of the actuals in the call. For function calls,
6640 -- propagate the dimensions from the returned type to N.
6644 -- All done, evaluate call and deal with elaboration issues
6648 -- Annotate the tree by creating a call marker in case the original call
6649 -- is transformed by expansion. The call marker is automatically saved
6650 -- for later examination by the ABE Processing phase.
6654 -- In GNATprove mode, expansion is disabled, but we want to inline some
6655 -- subprograms to facilitate formal verification. Indirect calls through
6656 -- a subprogram type or within a generic cannot be inlined. Inlining is
6657 -- performed only for calls subject to SPARK_Mode on.
6659 if GNATprove_Mode
6662 and then not Inside_A_Generic
6663 then
6670 -- Nothing to do if the subprogram is not eligible for inlining in
6671 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6675 or else Debug_Flag_M
6676 then
6679 -- Calls cannot be inlined inside assertions, as GNATprove treats
6680 -- assertions as logic expressions. Only issue a message when the
6681 -- body has been seen, otherwise this leads to spurious messages
6682 -- on expression functions.
6686 Cannot_Inline
6690 -- Calls cannot be inlined inside default expressions
6693 Cannot_Inline
6696 -- Inlining should not be performed during pre-analysis
6700 -- Do not inline calls inside expression functions, as this
6701 -- would prevent interpreting them as logical formulas in
6702 -- GNATprove. Only issue a message when the body has been seen,
6703 -- otherwise this leads to spurious messages on callees that
6704 -- are themselves expression functions.
6707 and then Is_Expression_Function_Or_Completion
6709 then
6712 then
6713 Cannot_Inline
6718 -- With the one-pass inlining technique, a call cannot be
6719 -- inlined if the corresponding body has not been seen yet.
6722 Cannot_Inline
6725 -- Nothing to do if there is no body to inline, indicating that
6726 -- the subprogram is not suitable for inlining in GNATprove
6727 -- mode.
6732 -- Calls cannot be inlined inside potentially unevaluated
6733 -- expressions, as this would create complex actions inside
6734 -- expressions, that are not handled by GNATprove.
6737 Cannot_Inline
6741 -- Do not inline calls which would possibly lead to missing a
6742 -- type conversion check on an input parameter.
6745 Cannot_Inline
6749 -- Otherwise, inline the call
6751 else
6763 -----------------------------
6764 -- Resolve_Case_Expression --
6765 -----------------------------
6773 begin
6785 -- When the expression is of a scalar subtype different from the
6786 -- result subtype, then insert a conversion to ensure the generation
6787 -- of a constraint check.
6797 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6798 -- dynamically tagged must be known statically.
6806 Error_Msg_N
6820 -------------------------------
6821 -- Resolve_Character_Literal --
6822 -------------------------------
6828 begin
6829 -- Verify that the character does belong to the type of the context
6834 -- Wide_Wide_Character literals must always be defined, since the set
6835 -- of wide wide character literals is complete, i.e. if a character
6836 -- literal is accepted by the parser, then it is OK for wide wide
6837 -- character (out of range character literals are rejected).
6842 -- Always accept character literal for type Any_Character, which
6843 -- occurs in error situations and in comparisons of literals, both
6844 -- of which should accept all literals.
6849 -- For Standard.Character or a type derived from it, check that the
6850 -- literal is in range.
6857 -- For Standard.Wide_Character or a type derived from it, check that the
6858 -- literal is in range.
6865 -- If the entity is already set, this has already been resolved in a
6866 -- generic context, or comes from expansion. Nothing else to do.
6871 -- Otherwise we have a user defined character type, and we can use the
6872 -- standard visibility mechanisms to locate the referenced entity.
6874 else
6887 -- If we fall through, then the literal does not match any of the
6888 -- entries of the enumeration type. This isn't just a constraint error
6889 -- situation, it is an illegality (see RM 4.2).
6891 Error_Msg_NE
6895 ---------------------------
6896 -- Resolve_Comparison_Op --
6897 ---------------------------
6899 -- Context requires a boolean type, and plays no role in resolution.
6900 -- Processing identical to that for equality operators. The result type is
6901 -- the base type, which matters when pathological subtypes of booleans with
6902 -- limited ranges are used.
6909 begin
6910 -- If this is an intrinsic operation which is not predefined, use the
6911 -- types of its declared arguments to resolve the possibly overloaded
6912 -- operands. Otherwise the operands are unambiguous and specify the
6913 -- expected type.
6918 else
6929 -- Skip remaining processing if already set to Any_Type
6935 -- Deal with other error cases
6939 T = Any_Character
6940 then
6943 else
6951 -- Resolve the operands if types OK
6960 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6961 -- types or array types except String.
6964 Check_SPARK_05_Restriction
6969 then
6970 Check_SPARK_05_Restriction
6974 -- Check comparison on unordered enumeration
6978 Error_Msg_NE
6985 -- Evaluate the relation (note we do this after the above check since
6986 -- this Eval call may change N to True/False. Skip this evaluation
6987 -- inside assertions, in order to keep assertions as written by users
6988 -- for tools that rely on these, e.g. GNATprove for loop invariants.
6989 -- Except evaluation is still performed even inside assertions for
6990 -- comparisons between values of universal type, which are useless
6991 -- for static analysis tools, and not supported even by GNATprove.
6995 and then
6997 then
7002 -----------------------------------------
7003 -- Resolve_Discrete_Subtype_Indication --
7004 -----------------------------------------
7006 procedure Resolve_Discrete_Subtype_Indication
7009 is
7013 begin
7021 else
7031 Error_Msg_NE
7034 -- Rewrite the constraint as a range of Typ
7035 -- to allow compilation to proceed further.
7047 else
7051 -- Additionally, we must check that the bounds are compatible
7052 -- with the given subtype, which might be different from the
7053 -- type of the context.
7057 -- ??? If the above check statically detects a Constraint_Error
7058 -- it replaces the offending bound(s) of the range R with a
7059 -- Constraint_Error node. When the itype which uses these bounds
7060 -- is frozen the resulting call to Duplicate_Subexpr generates
7061 -- a new temporary for the bounds.
7063 -- Unfortunately there are other itypes that are also made depend
7064 -- on these bounds, so when Duplicate_Subexpr is called they get
7065 -- a forward reference to the newly created temporaries and Gigi
7066 -- aborts on such forward references. This is probably sign of a
7067 -- more fundamental problem somewhere else in either the order of
7068 -- itype freezing or the way certain itypes are constructed.
7070 -- To get around this problem we call Remove_Side_Effects right
7071 -- away if either bounds of R are a Constraint_Error.
7073 declare
7077 begin
7093 -------------------------
7094 -- Resolve_Entity_Name --
7095 -------------------------
7097 -- Used to resolve identifiers and expanded names
7100 function Is_Assignment_Or_Object_Expression
7103 -- Determine whether node Context denotes an assignment statement or an
7104 -- object declaration whose expression is node Expr.
7106 ----------------------------------------
7107 -- Is_Assignment_Or_Object_Expression --
7108 ----------------------------------------
7110 function Is_Assignment_Or_Object_Expression
7113 is
7114 begin
7116 N_Object_Declaration)
7118 then
7121 -- Check whether a construct that yields a name is the expression of
7122 -- an assignment statement or an object declaration.
7125 N_Explicit_Dereference,
7126 N_Indexed_Component,
7127 N_Selected_Component,
7128 N_Slice)
7130 or else
7132 N_Unchecked_Type_Conversion)
7134 then
7135 return
7136 Is_Assignment_Or_Object_Expression
7140 -- Otherwise the context is not an assignment statement or an object
7141 -- declaration.
7143 else
7148 -- Local variables
7153 -- Start of processing for Resolve_Entity_Name
7155 begin
7156 -- If garbage from errors, set to Any_Type and return
7163 -- Replace named numbers by corresponding literals. Note that this is
7164 -- the one case where Resolve_Entity_Name must reset the Etype, since
7165 -- it is currently marked as universal.
7175 -- For enumeration literals, we need to make sure that a proper style
7176 -- check is done, since such literals are overloaded, and thus we did
7177 -- not do a style check during the first phase of analysis.
7183 -- Case of (sub)type name appearing in a context where an expression
7184 -- is expected. This is legal if occurrence is a current instance.
7185 -- See RM 8.6 (17/3).
7191 -- Any other use is an error
7193 else
7194 Error_Msg_N
7198 -- Check discriminant use if entity is discriminant in current scope,
7199 -- i.e. discriminant of record or concurrent type currently being
7200 -- analyzed. Uses in corresponding body are unrestricted.
7205 then
7208 -- A parameterless generic function cannot appear in a context that
7209 -- requires resolution.
7214 -- In Ada 83 an OUT parameter cannot be read
7219 or else Is_Assignment_Or_Object_Expression
7222 then
7227 -- In all other cases, just do the possible static evaluation
7229 else
7230 -- A deferred constant that appears in an expression must have a
7231 -- completion, unless it has been removed by in-place expansion of
7232 -- an aggregate. A constant that is a renaming does not need
7233 -- initialization.
7239 and then not In_Spec_Expression
7242 then
7246 then
7248 else
7249 Error_Msg_N
7259 -- When the entity appears in a parameter association, retrieve the
7260 -- related subprogram call.
7268 -- The following checks are only relevant when SPARK_Mode is on as
7269 -- they are not standard Ada legality rules.
7273 -- An effectively volatile object subject to enabled properties
7274 -- Async_Writers or Effective_Reads must appear in non-interfering
7275 -- context (SPARK RM 7.1.3(12)).
7282 then
7283 SPARK_Msg_N
7288 -- The variable may eventually become a constituent of a single
7289 -- protected/task type. Record the reference now and verify its
7290 -- legality when analyzing the contract of the variable
7291 -- (SPARK RM 9.3).
7298 -- A Ghost entity must appear in a specific context
7308 -------------------
7309 -- Resolve_Entry --
7310 -------------------
7322 -- If the bounds of the entry family being called depend on task
7323 -- discriminants, build a new index subtype where a discriminant is
7324 -- replaced with the value of the discriminant of the target task.
7325 -- The target task is the prefix of the entry name in the call.
7327 -----------------------
7328 -- Actual_Index_Type --
7329 -----------------------
7339 -- If the bound is given by a discriminant, replace with a reference
7340 -- to the discriminant of the same name in the target task. If the
7341 -- entry name is the target of a requeue statement and the entry is
7342 -- in the current protected object, the bound to be used is the
7343 -- discriminal of the object (see Apply_Range_Checks for details of
7344 -- the transformation).
7346 -----------------------------
7347 -- Actual_Discriminant_Ref --
7348 -----------------------------
7354 begin
7359 then
7365 then
7366 -- Note: here Bound denotes a discriminant of the corresponding
7367 -- record type tskV, whose discriminal is a formal of the
7368 -- init-proc tskVIP. What we want is the body discriminal,
7369 -- which is associated to the discriminant of the original
7370 -- concurrent type tsk.
7372 return New_Occurrence_Of
7375 else
7376 Ref :=
7386 -- Start of processing for Actual_Index_Type
7388 begin
7391 then
7394 else
7408 -- Start of processing for Resolve_Entry
7410 begin
7411 -- Find name of entry being called, and resolve prefix of name with its
7412 -- own type. The prefix can be overloaded, and the name and signature of
7413 -- the entry must be taken into account.
7417 -- Case of dealing with entry family within the current tasks
7421 else
7427 -- Entry call to an entry (or entry family) in the current task. This
7428 -- is legal even though the task will deadlock. Rewrite as call to
7429 -- current task.
7431 -- This can also be a call to an entry in an enclosing task. If this
7432 -- is a single task, we have to retrieve its name, because the scope
7433 -- of the entry is the task type, not the object. If the enclosing
7434 -- task is a task type, the identity of the task is given by its own
7435 -- self variable.
7437 -- Finally this can be a requeue on an entry of the same task or
7438 -- protected object.
7445 then
7446 -- S is an enclosing task or protected object. The concurrent
7447 -- declaration has been converted into a type declaration, and
7448 -- the object itself has an object declaration that follows
7449 -- the type in the same declarative part.
7461 -- Call to current task. Will be transformed into call to Self
7468 New_N :=
7471 Selector_Name =>
7478 then
7479 -- Use the entry name (which must be unique at this point) to find
7480 -- the prefix that returns the corresponding task/protected type.
7482 declare
7488 begin
7510 -- Generate a reference for the index when it denotes an entity
7516 -- Up to this point the expression could have been the actual in a
7517 -- simple entry call, and be given by a named association.
7521 else
7527 ------------------------
7528 -- Resolve_Entry_Call --
7529 ------------------------
7540 begin
7541 -- We kill all checks here, because it does not seem worth the effort to
7542 -- do anything better, an entry call is a big operation.
7544 Kill_All_Checks;
7546 -- Processing of the name is similar for entry calls and protected
7547 -- operation calls. Once the entity is determined, we can complete
7548 -- the resolution of the actuals.
7550 -- The selector may be overloaded, in the case of a protected object
7551 -- with overloaded functions. The type of the context is used for
7552 -- resolution.
7557 then
7558 declare
7562 begin
7581 -- Simple entry or protected operation call
7594 -- Call to member of entry family
7601 -- We cannot in general check the maximum depth of protected entry calls
7602 -- at compile time. But we can tell that any protected entry call at all
7603 -- violates a specified nesting depth of zero.
7609 -- Use context type to disambiguate a protected function that can be
7610 -- called without actuals and that returns an array type, and where the
7611 -- argument list may be an indexing of the returned value.
7616 and then
7622 and then
7623 Covers
7626 then
7627 declare
7630 begin
7631 Index_Node :=
7633 Prefix =>
7637 -- Since we are correcting a node classification error made by the
7638 -- parser, we call Replace rather than Rewrite.
7651 then
7652 -- Note the entity being called before rewriting the call, so that
7653 -- it appears used at this point.
7657 -- Rewrite as call to the precondition wrapper, adding the task
7658 -- object to the list of actuals. If the call is to a member of an
7659 -- entry family, include the index as well.
7661 declare
7665 begin
7674 New_Call :=
7676 Name =>
7681 -- Preanalyze and resolve new call. Current procedure is called
7682 -- from Resolve_Call, after which expansion will take place.
7689 -- The operation name may have been overloaded. Order the actuals
7690 -- according to the formals of the resolved entity, and set the return
7691 -- type to that of the operation.
7698 -- Reset the Is_Overloaded flag, since resolution is now completed
7700 -- Simple entry call
7705 -- Call to a member of an entry family
7715 -- Create a call reference to the entry
7723 -- Verify that a procedure call cannot masquerade as an entry
7724 -- call where an entry call is expected.
7729 then
7734 then
7739 then
7744 -- After resolution, entry calls and protected procedure calls are
7745 -- changed into entry calls, for expansion. The structure of the node
7746 -- does not change, so it can safely be done in place. Protected
7747 -- function calls must keep their structure because they are
7748 -- subexpressions.
7752 -- A protected operation that is not a function may modify the
7753 -- corresponding object, and cannot apply to a constant. If this
7754 -- is an internal call, the prefix is the type itself.
7760 then
7761 Error_Msg_N
7763 Entry_Name);
7766 declare
7769 begin
7770 Entry_Call :=
7775 -- Inherit relevant attributes from the original call
7777 Set_First_Named_Actual
7780 Set_Is_Elaboration_Checks_OK_Node
7783 Set_Is_SPARK_Mode_On_Node
7790 -- Protected functions can return on the secondary stack, in which
7791 -- case we must trigger the transient scope mechanism.
7793 elsif Expander_Active
7795 then
7800 -------------------------
7801 -- Resolve_Equality_Op --
7802 -------------------------
7804 -- Both arguments must have the same type, and the boolean context does
7805 -- not participate in the resolution. The first pass verifies that the
7806 -- interpretation is not ambiguous, and the type of the left argument is
7807 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7808 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7809 -- though they carry a single (universal) type. Diagnose this case here.
7817 -- The resolution rule for if expressions requires that each such must
7818 -- have a unique type. This means that if several dependent expressions
7819 -- are of a non-null anonymous access type, and the context does not
7820 -- impose an expected type (as can be the case in an equality operation)
7821 -- the expression must be rejected.
7824 -- Attempt to explain the nature of a redundant comparison with True. If
7825 -- the expression N is too complex, this routine issues a general error
7826 -- message.
7829 -- In the case of allocators and access attributes, the context must
7830 -- provide an indication of the specific access type to be used. If
7831 -- one operand is of such a "generic" access type, check whether there
7832 -- is a specific visible access type that has the same designated type.
7833 -- This is semantically dubious, and of no interest to any real code,
7834 -- but c48008a makes it all worthwhile.
7836 -------------------------
7837 -- Check_If_Expression --
7838 -------------------------
7844 begin
7851 then
7857 ------------------------
7858 -- Explain_Redundancy --
7859 ------------------------
7866 begin
7869 -- Strip the operand down to an entity
7871 loop
7874 else
7879 -- The construct denotes an entity
7884 -- Do not generate an error message when the comparison is done
7885 -- against the enumeration literal Standard.True.
7889 -- Build a customized error message
7916 -- The construct is too complex to disect, issue a general message
7918 else
7923 -----------------------------
7924 -- Find_Unique_Access_Type --
7925 -----------------------------
7932 begin
7934 E_Access_Attribute_Type)
7935 then
7939 E_Access_Attribute_Type)
7940 then
7942 else
7954 then
7967 -- Start of processing for Resolve_Equality_Op
7969 begin
7980 T = Any_Character
7981 then
7984 else
7993 then
8002 -- If expressions must have a single type, and if the context does
8003 -- not impose one the dependent expressions cannot be anonymous
8004 -- access types.
8006 -- Why no similar processing for case expressions???
8010 E_Anonymous_Access_Subprogram_Type)
8012 E_Anonymous_Access_Subprogram_Type)
8013 then
8021 -- In SPARK, equality operators = and /= for array types other than
8022 -- String are only defined when, for each index position, the
8023 -- operands have equal static bounds.
8027 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8028 -- operation if not needed.
8036 then
8037 Check_SPARK_05_Restriction
8042 -- If the unique type is a class-wide type then it will be expanded
8043 -- into a dispatching call to the predefined primitive. Therefore we
8044 -- check here for potential violation of such restriction.
8050 -- Only warn for redundant equality comparison to True for objects
8051 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8052 -- other expressions, it may be a matter of preference to write
8053 -- "Expr = True" or "Expr".
8055 if Warn_On_Redundant_Constructs
8060 and then
8062 or else
8064 then
8065 Error_Msg_N -- CODEFIX
8075 -- If this is an inequality, it may be the implicit inequality
8076 -- created for a user-defined operation, in which case the corres-
8077 -- ponding equality operation is not intrinsic, and the operation
8078 -- cannot be constant-folded. Else fold.
8083 or else Is_Intrinsic_Subprogram
8085 then
8091 then
8095 -- Ada 2005: If one operand is an anonymous access type, convert the
8096 -- other operand to it, to ensure that the underlying types match in
8097 -- the back-end. Same for access_to_subprogram, and the conversion
8098 -- verifies that the types are subtype conformant.
8100 -- We apply the same conversion in the case one of the operands is a
8101 -- private subtype of the type of the other.
8103 -- Why the Expander_Active test here ???
8105 if Expander_Active
8106 and then
8108 E_Anonymous_Access_Subprogram_Type)
8110 then
8130 ----------------------------------
8131 -- Resolve_Explicit_Dereference --
8132 ----------------------------------
8140 -- The candidate prefix type, if overloaded
8145 begin
8149 -- A useful optimization: check whether the dereference denotes an
8150 -- element of a container, and if so rewrite it as a call to the
8151 -- corresponding Element function.
8153 -- Disabled for now, on advice of ARG. A more restricted form of the
8154 -- predicate might be acceptable ???
8156 -- if Is_Container_Element (N) then
8157 -- return;
8158 -- end if;
8162 -- Use the context type to select the prefix that has the correct
8163 -- designated type. Keep the first match, which will be the inner-
8164 -- most.
8171 then
8176 -- Remove access types that do not match, but preserve access
8177 -- to subprogram interpretations, in case a further dereference
8178 -- is needed (see below).
8191 else
8192 -- If no interpretation covers the designated type of the prefix,
8193 -- this is the pathological case where not all implementations of
8194 -- the prefix allow the interpretation of the node as a call. Now
8195 -- that the expected type is known, Remove other interpretations
8196 -- from prefix, rewrite it as a call, and resolve again, so that
8197 -- the proper call node is generated.
8208 New_N :=
8210 Name =>
8221 -- If not overloaded, resolve P with its own type
8223 else
8227 -- If the prefix might be null, add an access check
8231 then
8235 -- If the designated type is a packed unconstrained array type, and the
8236 -- explicit dereference is not in the context of an attribute reference,
8237 -- then we must compute and set the actual subtype, since it is needed
8238 -- by Gigi. The reason we exclude the attribute case is that this is
8239 -- handled fine by Gigi, and in fact we use such attributes to build the
8240 -- actual subtype. We also exclude generated code (which builds actual
8241 -- subtypes directly if they are needed).
8248 then
8254 -- Note: No Eval processing is required for an explicit dereference,
8255 -- because such a name can never be static.
8259 -------------------------------------
8260 -- Resolve_Expression_With_Actions --
8261 -------------------------------------
8264 begin
8267 -- If N has no actions, and its expression has been constant folded,
8268 -- then rewrite N as just its expression. Note, we can't do this in
8269 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8270 -- Expression (N) to be expanded again.
8274 then
8279 ----------------------------------
8280 -- Resolve_Generalized_Indexing --
8281 ----------------------------------
8289 begin
8290 -- In ASIS mode, propagate the information about the indexes back to
8291 -- to the original indexing node. The generalized indexing is either
8292 -- a function call, or a dereference of one. The actuals include the
8293 -- prefix of the original node, which is the container expression.
8302 loop
8311 -- If expression is to be reanalyzed, reset Generalized_Indexing
8312 -- to recreate call node, as is the case when the expression is
8313 -- part of an expression function.
8322 else
8328 ---------------------------
8329 -- Resolve_If_Expression --
8330 ---------------------------
8339 begin
8340 -- Defend against malformed expressions
8358 -- When the "then" expression is of a scalar subtype different from the
8359 -- result subtype, then insert a conversion to ensure the generation of
8360 -- a constraint check. The same is done for the else part below, again
8361 -- comparing subtypes rather than base types.
8368 -- If ELSE expression present, just resolve using the determined type
8369 -- If type is universal, resolve to any member of the class.
8378 else
8388 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8389 -- dynamically tagged must be known statically.
8394 then
8400 -- If no ELSE expression is present, root type must be Standard.Boolean
8401 -- and we provide a Standard.True result converted to the appropriate
8402 -- Boolean type (in case it is a derived boolean type).
8405 Else_Expr :=
8410 else
8424 -------------------------------
8425 -- Resolve_Indexed_Component --
8426 -------------------------------
8434 begin
8442 -- Use the context type to select the prefix that yields the correct
8443 -- component type.
8445 declare
8452 begin
8459 and then
8460 Covers
8463 then
8472 else
8478 else
8489 else
8496 -- If prefix is access type, dereference to get real array type.
8497 -- Note: we do not apply an access check because the expander always
8498 -- introduces an explicit dereference, and the check will happen there.
8504 -- If name was overloaded, set component type correctly now
8505 -- If a misplaced call to an entry family (which has no index types)
8506 -- return. Error will be diagnosed from calling context.
8510 else
8517 -- The prefix may have resolved to a string literal, in which case its
8518 -- etype has a special representation. This is only possible currently
8519 -- if the prefix is a static concatenation, written in functional
8520 -- notation.
8525 else
8532 else
8543 -- Do not generate the warning on suspicious index if we are analyzing
8544 -- package Ada.Tags; otherwise we will report the warning with the
8545 -- Prims_Ptr field of the dispatch table.
8548 or else not
8550 Ada_Tags)
8551 then
8556 -- If the array type is atomic, and the component is not atomic, then
8557 -- this is worth a warning, since we have a situation where the access
8558 -- to the component may cause extra read/writes of the atomic array
8559 -- object, or partial word accesses, which could be unexpected.
8565 and then Has_Atomic_Components
8568 then
8569 Error_Msg_N
8571 Error_Msg_N
8576 -----------------------------
8577 -- Resolve_Integer_Literal --
8578 -----------------------------
8581 begin
8586 --------------------------------
8587 -- Resolve_Intrinsic_Operator --
8588 --------------------------------
8597 -- If the operand is a literal, it cannot be the expression in a
8598 -- conversion. Use a qualified expression instead.
8600 ---------------------
8601 -- Convert_Operand --
8602 ---------------------
8608 begin
8610 Res :=
8616 else
8623 -- Start of processing for Resolve_Intrinsic_Operator
8625 begin
8626 -- We must preserve the original entity in a generic setting, so that
8627 -- the legality of the operation can be verified in an instance.
8642 -- If the result or operand types are private, rewrite with unchecked
8643 -- conversions on the operands and the result, to expose the proper
8644 -- underlying numeric type.
8649 then
8654 else
8675 then
8676 -- Add explicit conversion where needed, and save interpretations in
8677 -- case operands are overloaded.
8684 else
8690 else
8700 else
8705 --------------------------------------
8706 -- Resolve_Intrinsic_Unary_Operator --
8707 --------------------------------------
8709 procedure Resolve_Intrinsic_Unary_Operator
8712 is
8717 begin
8736 else
8741 ------------------------
8742 -- Resolve_Logical_Op --
8743 ------------------------
8748 begin
8751 -- Predefined operations on scalar types yield the base type. On the
8752 -- other hand, logical operations on arrays yield the type of the
8753 -- arguments (and the context).
8757 else
8761 -- The following test is required because the operands of the operation
8762 -- may be literals, in which case the resulting type appears to be
8763 -- compatible with a signed integer type, when in fact it is compatible
8764 -- only with modular types. If the context itself is universal, the
8765 -- operation is illegal.
8773 Error_Msg_N
8781 then
8785 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8786 -- is active and the result type is standard Boolean (do not mess with
8787 -- ops that return a nonstandard Boolean type, because something strange
8788 -- is going on).
8790 -- Note: you might expect this replacement to be done during expansion,
8791 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8792 -- is used, no part of the right operand of an "and" or "or" operator
8793 -- should be executed if the left operand would short-circuit the
8794 -- evaluation of the corresponding "and then" or "or else". If we left
8795 -- the replacement to expansion time, then run-time checks associated
8796 -- with such operands would be evaluated unconditionally, due to being
8797 -- before the condition prior to the rewriting as short-circuit forms
8798 -- during expansion.
8800 if Short_Circuit_And_Or
8803 then
8804 -- Mark the corresponding putative SCO operator as truly a logical
8805 -- (and short-circuit) operator.
8818 -- Case of OR changed to OR ELSE
8820 else
8828 -- Return now, since analysis of the rewritten ops will take care of
8829 -- other reference bookkeeping and expression folding.
8844 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8845 -- only when both operands have same static lower and higher bounds. Of
8846 -- course the types have to match, so only check if operands are
8847 -- compatible and the node itself has no errors.
8851 then
8852 declare
8856 begin
8857 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8858 -- operation if not needed.
8865 then
8866 Check_SPARK_05_Restriction
8873 ---------------------------
8874 -- Resolve_Membership_Op --
8875 ---------------------------
8877 -- The context can only be a boolean type, and does not determine the
8878 -- arguments. Arguments should be unambiguous, but the preference rule for
8879 -- universal types applies.
8889 -- Analysis has determined a unique type for the left operand. Use it to
8890 -- resolve the disjuncts.
8892 ----------------------------
8893 -- Resolve_Set_Membership --
8894 ----------------------------
8900 begin
8901 -- If the left operand is overloaded, find type compatible with not
8902 -- overloaded alternative of the right operand.
8911 else
8916 -- Unclear how to resolve expression if all alternatives are also
8917 -- overloaded.
8923 else
8932 -- Alternative is an expression, a range
8933 -- or a subtype mark.
8937 then
8944 -- Check for duplicates for discrete case
8947 declare
8956 begin
8957 -- Loop checking duplicates. This is quadratic, but giant sets
8958 -- are unlikely in this context so it's a reasonable choice.
8965 N_Character_Literal)
8967 then
8985 -- Start of processing for Resolve_Membership_Op
8987 begin
8993 Resolve_Set_Membership;
8997 and then
8999 or else
9002 then
9005 -- Ada 2005 (AI-251): Support the following case:
9007 -- type I is interface;
9008 -- type T is tagged ...
9010 -- function Test (O : I'Class) is
9011 -- begin
9012 -- return O in T'Class.
9013 -- end Test;
9015 -- In this case we have nothing else to do. The membership test will be
9016 -- done at run time.
9023 then
9025 else
9029 -- If mixed-mode operations are present and operands are all literal,
9030 -- the only interpretation involves Duration, which is probably not
9031 -- the intention of the programmer.
9046 then
9052 else
9057 -- Here after resolving membership operation
9064 ------------------
9065 -- Resolve_Null --
9066 ------------------
9071 begin
9072 -- Handle restriction against anonymous null access values This
9073 -- restriction can be turned off using -gnatdj.
9075 -- Ada 2005 (AI-231): Remove restriction
9078 and then not Debug_Flag_J
9081 then
9082 -- In the common case of a call which uses an explicitly null value
9083 -- for an access parameter, give specialized error message.
9086 Error_Msg_N
9089 -- Standard message for all other cases (are there any?)
9091 else
9092 Error_Msg_N
9097 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9098 -- assignment to a null-excluding object
9103 then
9105 Insert_Action
9110 else
9117 -- In a distributed context, null for a remote access to subprogram may
9118 -- need to be replaced with a special record aggregate. In this case,
9119 -- return after having done the transformation.
9124 then
9128 -- The null literal takes its type from the context
9133 -----------------------
9134 -- Resolve_Op_Concat --
9135 -----------------------
9139 -- We wish to avoid deep recursion, because concatenations are often
9140 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9141 -- operands nonrecursively until we find something that is not a simple
9142 -- concatenation (A in this case). We resolve that, and then walk back
9143 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9144 -- to do the rest of the work at each level. The Parent pointers allow
9145 -- us to avoid recursion, and thus avoid running out of memory. See also
9146 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9151 begin
9152 -- The following code is equivalent to:
9154 -- Resolve_Op_Concat_First (NN, Typ);
9155 -- Resolve_Op_Concat_Arg (N, ...);
9156 -- Resolve_Op_Concat_Rest (N, Typ);
9158 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9159 -- operand is a concatenation.
9161 -- Walk down left operands
9163 loop
9172 -- Now (given the above example) NN is A&B and Op1 is A
9174 -- First resolve Op1 ...
9178 -- ... then walk NN back up until we reach N (where we started), calling
9179 -- Resolve_Op_Concat_Rest along the way.
9181 loop
9188 Check_SPARK_05_Restriction
9193 ---------------------------
9194 -- Resolve_Op_Concat_Arg --
9195 ---------------------------
9197 procedure Resolve_Op_Concat_Arg
9202 is
9206 begin
9208 if Is_Comp
9212 then
9214 else
9218 -- If both Array & Array and Array & Component are visible, there is a
9219 -- potential ambiguity that must be reported.
9224 then
9228 -- If the operation is user-defined and not overloaded use its
9229 -- profile. The operation may be a renaming, in which case it has
9230 -- been rewritten, and we want the original profile.
9235 then
9237 Etype
9241 -- Otherwise an aggregate may match both the array type and the
9242 -- component type.
9244 else
9249 else
9253 then
9254 declare
9259 begin
9264 -- Special-case the error message when the overloading is
9265 -- caused by a function that yields an array and can be
9266 -- called without parameters.
9271 Error_Msg_NE
9273 Error_Msg_NE
9277 else
9285 or else
9287 then
9288 Error_Msg_N -- CODEFIX
9306 else
9311 else
9315 -- Concatenation is restricted in SPARK: each operand must be either a
9316 -- string literal, the name of a string constant, a static character or
9317 -- string expression, or another concatenation. Arg cannot be a
9318 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9319 -- separately on each final operand, past concatenation operations.
9323 Check_SPARK_05_Restriction
9331 then
9332 Check_SPARK_05_Restriction
9336 -- Do not issue error on an operand that is neither a character nor a
9337 -- string, as the error is issued in Resolve_Op_Concat.
9339 else
9346 -----------------------------
9347 -- Resolve_Op_Concat_First --
9348 -----------------------------
9355 begin
9356 -- The parser folds an enormous sequence of concatenations of string
9357 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9358 -- in the right operand. If the expression resolves to a predefined "&"
9359 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9360 -- we give an error. See P_Simple_Expression in Par.Ch4.
9365 then
9380 ----------------------------
9381 -- Resolve_Op_Concat_Rest --
9382 ----------------------------
9388 begin
9397 -- If this is not a static concatenation, but the result is a string
9398 -- type (and not an array of strings) ensure that static string operands
9399 -- have their subtypes properly constructed.
9403 then
9409 ----------------------
9410 -- Resolve_Op_Expon --
9411 ----------------------
9416 begin
9417 -- Catch attempts to do fixed-point exponentiation with universal
9418 -- operands, which is a case where the illegality is not caught during
9419 -- normal operator analysis. This is not done in preanalysis mode
9420 -- since the tree is not fully decorated during preanalysis.
9432 then
9442 then
9449 then
9453 -- We do the resolution using the base type, because intermediate values
9454 -- in expressions are always of the base type, not a subtype of it.
9459 -- For integer types, right argument must be in Natural range
9474 -- Evaluate the exponentiation operator for dimensioned type
9477 else
9481 -- Set overflow checking bit. Much cleverer code needed here eventually
9482 -- and perhaps the Resolve routines should be separated for the various
9483 -- arithmetic operations, since they will need different processing. ???
9492 --------------------
9493 -- Resolve_Op_Not --
9494 --------------------
9500 -- This function determines if the parent node is a boolean operator or
9501 -- operation (comparison op, membership test, or short circuit form) and
9502 -- the not in question is the left operand of this operation. Note that
9503 -- if the not is in parens, then false is returned.
9505 -----------------------
9506 -- Parent_Is_Boolean --
9507 -----------------------
9510 begin
9514 else
9516 when N_And_Then
9517 | N_In
9518 | N_Not_In
9519 | N_Op_And
9520 | N_Op_Eq
9521 | N_Op_Ge
9522 | N_Op_Gt
9523 | N_Op_Le
9524 | N_Op_Lt
9525 | N_Op_Ne
9526 | N_Op_Or
9527 | N_Op_Xor
9528 | N_Or_Else
9529 =>
9538 -- Start of processing for Resolve_Op_Not
9540 begin
9541 -- Predefined operations on scalar types yield the base type. On the
9542 -- other hand, logical operations on arrays yield the type of the
9543 -- arguments (and the context).
9547 else
9551 -- Straightforward case of incorrect arguments
9558 -- Special case of probable missing parens
9562 Error_Msg_N
9565 else
9566 Error_Msg_N
9573 -- OK resolution of NOT
9575 else
9576 -- Warn if non-boolean types involved. This is a case like not a < b
9577 -- where a and b are modular, where we will get (not a) < b and most
9578 -- likely not (a < b) was intended.
9580 if Warn_On_Questionable_Missing_Parens
9582 and then Parent_Is_Boolean
9583 then
9587 -- Warn on double negation if checking redundant constructs
9589 if Warn_On_Redundant_Constructs
9594 then
9598 -- Complete resolution and evaluation of NOT
9608 -----------------------------
9609 -- Resolve_Operator_Symbol --
9610 -----------------------------
9612 -- Nothing to be done, all resolved already
9618 begin
9622 ----------------------------------
9623 -- Resolve_Qualified_Expression --
9624 ----------------------------------
9632 begin
9635 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9636 -- operation if not needed.
9643 then
9644 Check_SPARK_05_Restriction
9648 -- A qualified expression requires an exact match of the type, class-
9649 -- wide matching is not allowed. However, if the qualifying type is
9650 -- specific and the expression has a class-wide type, it may still be
9651 -- okay, since it can be the result of the expansion of a call to a
9652 -- dispatching function, so we also have to check class-wideness of the
9653 -- type of the expression's original node.
9656 or else
9660 then
9664 -- If the target type is unconstrained, then we reset the type of the
9665 -- result from the type of the expression. For other cases, the actual
9666 -- subtype of the expression is the target type.
9670 then
9677 -- If we still have a qualified expression after the static evaluation,
9678 -- then apply a scalar range check if needed. The reason that we do this
9679 -- after the Eval call is that otherwise, the application of the range
9680 -- check may convert an illegal static expression and result in warning
9681 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9687 -- Finally, check whether a predicate applies to the target type. This
9688 -- comes from AI12-0100. As for type conversions, check the enclosing
9689 -- context to prevent an infinite expansion.
9695 or else
9697 then
9700 -- In the case of a qualified expression in an allocator, the check
9701 -- is applied when expanding the allocator, so avoid redundant check.
9705 then
9711 ------------------------------
9712 -- Resolve_Raise_Expression --
9713 ------------------------------
9716 begin
9720 else
9725 -------------------
9726 -- Resolve_Range --
9727 -------------------
9734 -- Returns True if N is of the form X'First .. X'Last where X is the
9735 -- same entity for both attributes.
9737 --------------------
9738 -- First_Last_Ref --
9739 --------------------
9745 begin
9750 then
9751 declare
9754 begin
9758 then
9767 -- Start of processing for Resolve_Range
9769 begin
9772 -- The lower bound should be in Typ. The higher bound can be in Typ's
9773 -- base type if the range is null. It may still be invalid if it is
9774 -- higher than the lower bound. This is checked later in the context in
9775 -- which the range appears.
9780 -- Check for inappropriate range on unordered enumeration type
9784 -- Exclude X'First .. X'Last if X is the same entity for both
9786 and then not First_Last_Ref
9787 then
9789 Error_Msg_NE
9796 -- We have to check the bounds for being within the base range as
9797 -- required for a non-static context. Normally this is automatic and
9798 -- done as part of evaluating expressions, but the N_Range node is an
9799 -- exception, since in GNAT we consider this node to be a subexpression,
9800 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9801 -- this, but that would put the test on the main evaluation path for
9802 -- expressions.
9807 -- Check for an ambiguous range over character literals. This will
9808 -- happen with a membership test involving only literals.
9816 -- If bounds are static, constant-fold them, so size computations are
9817 -- identical between front-end and back-end. Do not perform this
9818 -- transformation while analyzing generic units, as type information
9819 -- would be lost when reanalyzing the constant node in the instance.
9832 --------------------------
9833 -- Resolve_Real_Literal --
9834 --------------------------
9839 begin
9840 -- Special processing for fixed-point literals to make sure that the
9841 -- value is an exact multiple of small where this is required. We skip
9842 -- this for the universal real case, and also for generic types.
9848 then
9849 declare
9856 begin
9857 -- Case of literal is not an exact multiple of the Small
9861 -- For a source program literal for a decimal fixed-point type,
9862 -- this is statically illegal (RM 4.9(36)).
9867 then
9871 -- Generate a warning if literal from source
9874 and then Warn_On_Bad_Fixed_Value
9875 then
9876 Error_Msg_N
9878 N);
9881 -- Replace literal by a value that is the exact representation
9882 -- of a value of the type, i.e. a multiple of the small value,
9883 -- by truncation, since Machine_Rounds is false for all GNAT
9884 -- fixed-point types (RM 4.9(38)).
9894 -- In all cases, set the corresponding integer field
9900 -- Now replace the actual type by the expected type as usual
9906 -----------------------
9907 -- Resolve_Reference --
9908 -----------------------
9913 begin
9914 -- Replace general access with specific type
9922 -- If we are taking the reference of a volatile entity, then treat it as
9923 -- a potential modification of this entity. This is too conservative,
9924 -- but necessary because remove side effects can cause transformations
9925 -- of normal assignments into reference sequences that otherwise fail to
9926 -- notice the modification.
9933 --------------------------------
9934 -- Resolve_Selected_Component --
9935 --------------------------------
9950 -- Check whether this is the initialization of a component within an
9951 -- init proc (by assignment or call to another init proc). If true,
9952 -- there is no need for a discriminant check.
9954 --------------------
9955 -- Init_Component --
9956 --------------------
9959 begin
9960 return Inside_Init_Proc
9966 -- Start of processing for Resolve_Selected_Component
9968 begin
9971 -- Use the context type to select the prefix that has a selector
9972 -- of the correct name and type.
9980 else
9984 -- Locate selected component. For a private prefix the selector
9985 -- can denote a discriminant.
9989 -- The visible components of a class-wide type are those of
9990 -- the root type.
10000 then
10007 else
10011 Error_Msg_N
10016 else
10019 -- There may be an implicit dereference. Retrieve
10020 -- designated record type.
10024 else
10030 -- Resolution chooses the new interpretation.
10031 -- Find the component with the right name.
10036 loop
10053 -- There must be a legal interpretation at this point
10060 else
10061 -- Resolve prefix with its type
10066 -- Generate cross-reference. We needed to wait until full overloading
10067 -- resolution was complete to do this, since otherwise we can't tell if
10068 -- we are an lvalue or not.
10072 else
10076 -- If prefix is an access type, the node will be transformed into an
10077 -- explicit dereference during expansion. The type of the node is the
10078 -- designated type of that of the prefix.
10083 else
10087 -- Set flag for expander if discriminant check required on a component
10088 -- appearing within a variant.
10094 and then
10097 and then not Init_Component
10098 then
10106 -- If the prefix is a record conversion, this may be a renamed
10107 -- discriminant whose bounds differ from those of the original
10108 -- one, so we must ensure that a range check is performed.
10113 then
10117 -- Note: No Eval processing is required, because the prefix is of a
10118 -- record type, or protected type, and neither can possibly be static.
10120 -- If the record type is atomic, and the component is non-atomic, then
10121 -- this is worth a warning, since we have a situation where the access
10122 -- to the component may cause extra read/writes of the atomic array
10123 -- object, or partial word accesses, both of which may be unexpected.
10129 then
10130 Error_Msg_N
10133 Error_Msg_N
10141 -------------------
10142 -- Resolve_Shift --
10143 -------------------
10150 begin
10151 -- We do the resolution using the base type, because intermediate values
10152 -- in expressions always are of the base type, not a subtype of it.
10165 ---------------------------
10166 -- Resolve_Short_Circuit --
10167 ---------------------------
10174 begin
10175 -- Ensure all actions associated with the left operand (e.g.
10176 -- finalization of transient objects) are fully evaluated locally within
10177 -- an expression with actions. This is particularly helpful for coverage
10178 -- analysis. However this should not happen in generics or if option
10179 -- Minimize_Expression_With_Actions is set.
10182 declare
10184 begin
10192 -- Set Comes_From_Source on L to preserve warnings for unset
10193 -- reference.
10202 -- Check for issuing warning for always False assert/check, this happens
10203 -- when assertions are turned off, in which case the pragma Assert/Check
10204 -- was transformed into:
10206 -- if False and then <condition> then ...
10208 -- and we detect this pattern
10210 if Warn_On_Assertion_Failure
10217 then
10218 declare
10221 begin
10222 -- Special handling of Asssert pragma
10226 then
10227 declare
10229 Original_Node
10230 (Expression
10233 begin
10234 -- Don't warn if original condition is explicit False,
10235 -- since obviously the failure is expected in this case.
10239 then
10242 -- Issue warning. We do not want the deletion of the
10243 -- IF/AND-THEN to take this message with it. We achieve this
10244 -- by making sure that the expanded code points to the Sloc
10245 -- of the expression, not the original pragma.
10247 else
10248 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10249 -- The source location of the expression is not usually
10250 -- the best choice here. For example, it gets located on
10251 -- the last AND keyword in a chain of boolean expressiond
10252 -- AND'ed together. It is best to put the message on the
10253 -- first character of the assertion, which is the effect
10254 -- of the First_Node call here.
10256 Error_Msg_F
10258 Expression
10263 -- Similar processing for Check pragma
10267 then
10268 -- Don't want to warn if original condition is explicit False
10270 declare
10272 Original_Node
10273 (Expression
10275 begin
10278 then
10281 -- Post warning
10283 else
10284 -- Again use Error_Msg_F rather than Error_Msg_N, see
10285 -- comment above for an explanation of why we do this.
10287 Error_Msg_F
10289 Expression
10297 -- Continue with processing of short circuit
10306 -------------------
10307 -- Resolve_Slice --
10308 -------------------
10317 begin
10320 -- Use the context type to select the prefix that yields the correct
10321 -- array type.
10323 declare
10330 begin
10338 then
10346 else
10351 else
10362 else
10372 -- If the prefix is an access to an unconstrained array, we must use
10373 -- the actual subtype of the object to perform the index checks. The
10374 -- object denoted by the prefix is implicit in the node, so we build
10375 -- an explicit representation for it in order to compute the actual
10376 -- subtype.
10381 declare
10385 begin
10396 then
10399 -- If the name is a selected component that depends on discriminants,
10400 -- build an actual subtype for it. This can happen only when the name
10401 -- itself is overloaded; otherwise the actual subtype is created when
10402 -- the selected component is analyzed.
10405 and then Full_Analysis
10407 then
10408 declare
10411 begin
10416 -- Maybe this should just be "else", instead of checking for the
10417 -- specific case of slice??? This is needed for the case where the
10418 -- prefix is an Image attribute, which gets expanded to a slice, and so
10419 -- has a constrained subtype which we want to use for the slice range
10420 -- check applied below (the range check won't get done if the
10421 -- unconstrained subtype of the 'Image is used).
10427 -- Obtain the type of the array index
10431 else
10435 -- If name was overloaded, set slice type correctly now
10439 -- Handle the generation of a range check that compares the array index
10440 -- against the discrete_range. The check is not applied to internally
10441 -- built nodes associated with the expansion of dispatch tables. Check
10442 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10443 -- the unit.
10445 if Tagged_Type_Expansion
10451 then
10454 -- The discrete_range is specified by a subtype indication. Create a
10455 -- shallow copy and inherit the type, parent and source location from
10456 -- the discrete_range. This ensures that the range check is inserted
10457 -- relative to the slice and that the runtime exception points to the
10458 -- proper construct.
10467 -- The discrete_range is a regular range. Resolve the bounds and remove
10468 -- their side effects.
10470 else
10487 -- Check bad use of type with predicates
10489 declare
10492 begin
10495 then
10497 else
10502 Bad_Predicated_Subtype_Use
10507 -- Otherwise here is where we check suspicious indexes
10518 ----------------------------
10519 -- Resolve_String_Literal --
10520 ----------------------------
10531 begin
10532 -- For a string appearing in a concatenation, defer creation of the
10533 -- string_literal_subtype until the end of the resolution of the
10534 -- concatenation, because the literal may be constant-folded away. This
10535 -- is a useful optimization for long concatenation expressions.
10537 -- If the string is an aggregate built for a single character (which
10538 -- happens in a non-static context) or a is null string to which special
10539 -- checks may apply, we build the subtype. Wide strings must also get a
10540 -- string subtype if they come from a one character aggregate. Strings
10541 -- generated by attributes might be static, but it is often hard to
10542 -- determine whether the enclosing context is static, so we generate
10543 -- subtypes for them as well, thus losing some rarer optimizations ???
10544 -- Same for strings that come from a static conversion.
10546 Need_Check :=
10555 -- If the resolving type is itself a string literal subtype, we can just
10556 -- reuse it, since there is no point in creating another.
10562 and then not Need_Check
10564 N_Attribute_Reference,
10565 N_Qualified_Expression,
10566 N_Type_Conversion)
10567 then
10570 -- Do not generate a string literal subtype for the default expression
10571 -- of a formal parameter in GNATprove mode. This is because the string
10572 -- subtype is associated with the freezing actions of the subprogram,
10573 -- however freezing is disabled in GNATprove mode and as a result the
10574 -- subtype is unavailable.
10576 elsif GNATprove_Mode
10578 then
10581 -- Otherwise we must create a string literal subtype. Note that the
10582 -- whole idea of string literal subtypes is simply to avoid the need
10583 -- for building a full fledged array subtype for each literal.
10585 else
10591 or else Need_Check
10592 then
10599 then
10605 -- The validity of a null string has been checked in the call to
10606 -- Eval_String_Literal.
10611 -- Always accept string literal with component type Any_Character, which
10612 -- occurs in error situations and in comparisons of literals, both of
10613 -- which should accept all literals.
10618 -- If the type is bit-packed, then we always transform the string
10619 -- literal into a full fledged aggregate.
10624 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10626 else
10627 -- For Standard.Wide_Wide_String, or any other type whose component
10628 -- type is Standard.Wide_Wide_Character, we know that all the
10629 -- characters in the string must be acceptable, since the parser
10630 -- accepted the characters as valid character literals.
10635 -- For the case of Standard.String, or any other type whose component
10636 -- type is Standard.Character, we must make sure that there are no
10637 -- wide characters in the string, i.e. that it is entirely composed
10638 -- of characters in range of type Character.
10640 -- If the string literal is the result of a static concatenation, the
10641 -- test has already been performed on the components, and need not be
10642 -- repeated.
10646 then
10650 -- If we are out of range, post error. This is one of the
10651 -- very few places that we place the flag in the middle of
10652 -- a token, right under the offending wide character. Not
10653 -- quite clear if this is right wrt wide character encoding
10654 -- sequences, but it's only an error message.
10656 Error_Msg
10663 -- For the case of Standard.Wide_String, or any other type whose
10664 -- component type is Standard.Wide_Character, we must make sure that
10665 -- there are no wide characters in the string, i.e. that it is
10666 -- entirely composed of characters in range of type Wide_Character.
10668 -- If the string literal is the result of a static concatenation,
10669 -- the test has already been performed on the components, and need
10670 -- not be repeated.
10674 then
10678 -- If we are out of range, post error. This is one of the
10679 -- very few places that we place the flag in the middle of
10680 -- a token, right under the offending wide character.
10682 -- This is not quite right, because characters in general
10683 -- will take more than one character position ???
10685 Error_Msg
10692 -- If the root type is not a standard character, then we will convert
10693 -- the string into an aggregate and will let the aggregate code do
10694 -- the checking. Standard Wide_Wide_Character is also OK here.
10696 else
10700 -- See if the component type of the array corresponding to the string
10701 -- has compile time known bounds. If yes we can directly check
10702 -- whether the evaluation of the string will raise constraint error.
10703 -- Otherwise we need to transform the string literal into the
10704 -- corresponding character aggregate and let the aggregate code do
10705 -- the checking.
10709 -- Check for the case of full range, where we are definitely OK
10715 -- Here the range is not the complete base type range, so check
10717 declare
10725 begin
10728 then
10734 then
10735 Apply_Compile_Time_Constraint_Error
10737 CE_Range_Check_Failed,
10748 -- If we got here we meed to transform the string literal into the
10749 -- equivalent qualified positional array aggregate. This is rather
10750 -- heavy artillery for this situation, but it is hard work to avoid.
10752 declare
10757 begin
10758 -- Build the character literals, we give them source locations that
10759 -- correspond to the string positions, which is a bit tricky given
10760 -- the possible presence of wide character escape sequences.
10774 -- Should we have a call to Skip_Wide here ???
10776 -- ??? else
10777 -- Skip_Wide (P);
10785 Expression =>
10792 -------------------------
10793 -- Resolve_Target_Name --
10794 -------------------------
10797 begin
10801 -----------------------------
10802 -- Resolve_Type_Conversion --
10803 -----------------------------
10815 -- Set to False to suppress cases where we want to suppress the test
10816 -- for redundancy to avoid possible false positives on this warning.
10818 begin
10819 if not Conv_OK
10821 then
10825 -- If the Operand Etype is Universal_Fixed, then the conversion is
10826 -- never redundant. We need this check because by the time we have
10827 -- finished the rather complex transformation, the conversion looks
10828 -- redundant when it is not.
10833 -- If the operand is marked as Any_Fixed, then special processing is
10834 -- required. This is also a case where we suppress the test for a
10835 -- redundant conversion, since most certainly it is not redundant.
10840 -- Mixed-mode operation involving a literal. Context must be a fixed
10841 -- type which is applied to the literal subsequently.
10843 -- Multiplication and division involving two fixed type operands must
10844 -- yield a universal real because the result is computed in arbitrary
10845 -- precision.
10851 then
10857 or else
10859 then
10860 -- Return if expression is ambiguous
10865 -- If nothing else, the available fixed type is Duration
10867 else
10871 -- Resolve the real operand with largest available precision
10875 else
10881 -- If the operand is a literal (it could be a non-static and
10882 -- illegal exponentiation) check whether the use of Duration
10883 -- is potentially inaccurate.
10888 then
10889 Error_Msg_N
10892 Error_Msg_N
10899 then
10902 else
10911 -- In SPARK, a type conversion between array types should be restricted
10912 -- to types which have matching static bounds.
10914 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10915 -- operation if not needed.
10922 then
10923 Check_SPARK_05_Restriction
10927 -- In formal mode, the operand of an ancestor type conversion must be an
10928 -- object (not an expression).
10936 then
10942 -- Note: we do the Eval_Type_Conversion call before applying the
10943 -- required checks for a subtype conversion. This is important, since
10944 -- both are prepared under certain circumstances to change the type
10945 -- conversion to a constraint error node, but in the case of
10946 -- Eval_Type_Conversion this may reflect an illegality in the static
10947 -- case, and we would miss the illegality (getting only a warning
10948 -- message), if we applied the type conversion checks first.
10952 -- Even when evaluation is not possible, we may be able to simplify the
10953 -- conversion or its expression. This needs to be done before applying
10954 -- checks, since otherwise the checks may use the original expression
10955 -- and defeat the simplifications. This is specifically the case for
10956 -- elimination of the floating-point Truncation attribute in
10957 -- float-to-int conversions.
10961 -- If after evaluation we still have a type conversion, then we may need
10962 -- to apply checks required for a subtype conversion.
10964 -- Skip these type conversion checks if universal fixed operands
10965 -- operands involved, since range checks are handled separately for
10966 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10972 then
10976 -- Issue warning for conversion of simple object to its own type. We
10977 -- have to test the original nodes, since they may have been rewritten
10978 -- by various optimizations.
10982 -- Here we test for a redundant conversion if the warning mode is
10983 -- active (and was not locally reset), and we have a type conversion
10984 -- from source not appearing in a generic instance.
10986 if Test_Redundant
10989 and then not In_Instance
10990 then
10994 -- If the node is part of a larger expression, the Target_Type
10995 -- may not be the original type of the node if the context is a
10996 -- condition. Recover original type to see if conversion is needed.
11000 then
11004 -- If we have an entity name, then give the warning if the entity
11005 -- is the right type, or if it is a loop parameter covered by the
11006 -- original type (that's needed because loop parameters have an
11007 -- odd subtype coming from the bounds).
11010 and then
11012 or else
11016 -- If not an entity, then type of expression must match
11019 then
11020 -- One more check, do not give warning if the analyzed conversion
11021 -- has an expression with non-static bounds, and the bounds of the
11022 -- target are static. This avoids junk warnings in cases where the
11023 -- conversion is necessary to establish staticness, for example in
11024 -- a case statement.
11028 then
11031 -- Finally, if this type conversion occurs in a context requiring
11032 -- a prefix, and the expression is a qualified expression then the
11033 -- type conversion is not redundant, since a qualified expression
11034 -- is not a prefix, whereas a type conversion is. For example, "X
11035 -- := T'(Funx(...)).Y;" is illegal because a selected component
11036 -- requires a prefix, but a type conversion makes it legal: "X :=
11037 -- T(T'(Funx(...))).Y;"
11039 -- In Ada 2012, a qualified expression is a name, so this idiom is
11040 -- no longer needed, but we still suppress the warning because it
11041 -- seems unfriendly for warnings to pop up when you switch to the
11042 -- newer language version.
11046 N_Indexed_Component,
11047 N_Selected_Component,
11048 N_Slice,
11049 N_Explicit_Dereference)
11050 then
11053 -- Never warn on conversion to Long_Long_Integer'Base since
11054 -- that is most likely an artifact of the extended overflow
11055 -- checking and comes from complex expanded code.
11060 -- Here we give the redundant conversion warning. If it is an
11061 -- entity, give the name of the entity in the message. If not,
11062 -- just mention the expression.
11064 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11066 else
11069 Error_Msg_NE -- CODEFIX
11072 else
11073 Error_Msg_NE
11081 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11082 -- No need to perform any interface conversion if the type of the
11083 -- expression coincides with the target type.
11086 and then Expander_Active
11088 then
11089 declare
11093 begin
11094 -- If the type of the operand is a limited view, use nonlimited
11095 -- view when available. If it is a class-wide type, recover the
11096 -- class-wide type of the nonlimited view.
11100 then
11116 -- Conversion from interface type
11120 -- Ada 2005 (AI-217): Handle entities from limited views
11124 Error_Msg_NE -- CODEFIX
11127 Error_Msg_N
11129 N);
11132 and then not
11135 then
11137 Error_Msg_NE -- CODEFIX
11140 Error_Msg_N
11142 N);
11144 else
11148 -- Conversion to interface type
11152 -- Handle subtypes
11159 or else Interface_Present_In_Ancestor
11162 then
11164 else
11167 Error_Msg_N
11175 -- Ada 2012: once the type conversion is resolved, check whether the
11176 -- operand statisfies the static predicate of the target type.
11182 -- If at this stage we have a real to integer conversion, make sure that
11183 -- the Do_Range_Check flag is set, because such conversions in general
11184 -- need a range check. We only need this if expansion is off.
11185 -- In GNATprove mode, we only do that when converting from fixed-point
11186 -- (as floating-point to integer conversions are now handled in
11187 -- GNATprove mode).
11190 and then not Expander_Active
11195 then
11199 -- Generating C code a type conversion of an access to constrained
11200 -- array type to access to unconstrained array type involves building
11201 -- a fat pointer which in general cannot be generated on the fly. We
11202 -- remove side effects in order to store the result of the conversion
11203 -- into a temporary.
11205 if Modify_Tree_For_C
11212 then
11217 ----------------------
11218 -- Resolve_Unary_Op --
11219 ----------------------
11228 begin
11231 Check_SPARK_05_Restriction
11235 -- Deal with intrinsic unary operators
11241 then
11246 -- Deal with universal cases
11249 or else
11251 then
11258 -- Generate warning for expressions like abs (x mod 2)
11260 if Warn_On_Redundant_Constructs
11262 then
11266 Error_Msg_N -- CODEFIX
11271 -- Deal with reference generation
11278 -- Set overflow checking bit. Much cleverer code needed here eventually
11279 -- and perhaps the Resolve routines should be separated for the various
11280 -- arithmetic operations, since they will need different processing ???
11288 -- Generate warning for expressions like -5 mod 3 for integers. No need
11289 -- to worry in the floating-point case, since parens do not affect the
11290 -- result so there is no point in giving in a warning.
11292 declare
11301 begin
11302 if Warn_On_Questionable_Missing_Parens
11306 then
11309 -- We are looking for cases where the right operand is not
11310 -- parenthesized, and is a binary operator, multiply, divide, or
11311 -- mod. These are the cases where the grouping can affect results.
11315 then
11316 -- For mod, we always give the warning, since the value is
11317 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11318 -- -(5 mod 315)). But for the other cases, the only concern is
11319 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11320 -- overflows, but (-2) * 64 does not). So we try to give the
11321 -- message only when overflow is possible.
11325 then
11330 else
11336 else
11340 -- Note that the test below is deliberately excluding the
11341 -- largest negative number, since that is a potentially
11342 -- troublesome case (e.g. -2 * x, where the result is the
11343 -- largest negative integer has an overflow with 2 * x).
11350 -- For the multiplication case, the only case we have to worry
11351 -- about is when (-a)*b is exactly the largest negative number
11352 -- so that -(a*b) can cause overflow. This can only happen if
11353 -- a is a power of 2, and more generally if any operand is a
11354 -- constant that is not a power of 2, then the parentheses
11355 -- cannot affect whether overflow occurs. We only bother to
11356 -- test the left most operand
11358 -- Loop looking at left operands for one that has known value
11365 -- Operand value of 0 or 1 skips warning
11370 -- Otherwise check power of 2, if power of 2, warn, if
11371 -- anything else, skip warning.
11373 else
11377 else
11386 -- Keep looking at left operands
11391 -- For rem or "/" we can only have a problematic situation
11392 -- if the divisor has a value of minus one or one. Otherwise
11393 -- overflow is impossible (divisor > 1) or we have a case of
11394 -- division by zero in any case.
11399 then
11403 -- If we fall through warning should be issued
11405 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11407 Error_Msg_N
11414 ----------------------------------
11415 -- Resolve_Unchecked_Expression --
11416 ----------------------------------
11418 procedure Resolve_Unchecked_Expression
11421 is
11422 begin
11427 ---------------------------------------
11428 -- Resolve_Unchecked_Type_Conversion --
11429 ---------------------------------------
11431 procedure Resolve_Unchecked_Type_Conversion
11434 is
11440 begin
11441 -- Resolve operand using its own type
11445 -- In an inlined context, the unchecked conversion may be applied
11446 -- to a literal, in which case its type is the type of the context.
11447 -- (In other contexts conversions cannot apply to literals).
11449 if In_Inlined_Body
11453 then
11461 ------------------------------
11462 -- Rewrite_Operator_As_Call --
11463 ------------------------------
11470 begin
11477 New_N :=
11488 ------------------------------
11489 -- Rewrite_Renamed_Operator --
11490 ------------------------------
11492 procedure Rewrite_Renamed_Operator
11496 is
11501 begin
11502 -- Do not perform this transformation within a pre/postcondition,
11503 -- because the expression will be reanalyzed, and the transformation
11504 -- might affect the visibility of the operator, e.g. in an instance.
11505 -- Note that fully analyzed and expanded pre/postconditions appear as
11506 -- pragma Check equivalents.
11512 -- Likewise when an expression function is being preanalyzed, since the
11513 -- expression will be reanalyzed as part of the generated body.
11516 declare
11518 begin
11521 N_Expression_Function
11522 then
11528 -- Rewrite the operator node using the real operator, not its renaming.
11529 -- Exclude user-defined intrinsic operations of the same name, which are
11530 -- treated separately and rewritten as calls.
11539 -- Indicate that both the original entity and its renaming are
11540 -- referenced at this point.
11551 -- If the context type is private, add the appropriate conversions so
11552 -- that the operator is applied to the full view. This is done in the
11553 -- routines that resolve intrinsic operators.
11557 when N_Op_Add
11558 | N_Op_Divide
11559 | N_Op_Expon
11560 | N_Op_Mod
11561 | N_Op_Multiply
11562 | N_Op_Rem
11563 | N_Op_Subtract
11564 =>
11567 when N_Op_Abs
11568 | N_Op_Minus
11569 | N_Op_Plus
11570 =>
11580 -- Operator renames a user-defined operator of the same name. Use the
11581 -- original operator in the node, which is the one Gigi knows about.
11588 -----------------------
11589 -- Set_Slice_Subtype --
11590 -----------------------
11592 -- Build an implicit subtype declaration to represent the type delivered by
11593 -- the slice. This is an abbreviated version of an array subtype. We define
11594 -- an index subtype for the slice, using either the subtype name or the
11595 -- discrete range of the slice. To be consistent with index usage elsewhere
11596 -- we create a list header to hold the single index. This list is not
11597 -- otherwise attached to the syntax tree.
11608 begin
11614 else
11615 -- We force the evaluation of a range. This is definitely needed in
11616 -- the renamed case, and seems safer to do unconditionally. Note in
11617 -- any case that since we will create and insert an Itype referring
11618 -- to this range, we must make sure any side effect removal actions
11619 -- are inserted before the Itype definition.
11625 -- If the discrete range is given by a subtype indication, the
11626 -- type of the slice is the base of the subtype mark.
11629 declare
11631 begin
11640 -- Take a new copy of Drange (where bounds have been rewritten to
11641 -- reference side-effect-free names). Using a separate tree ensures
11642 -- that further expansion (e.g. while rewriting a slice assignment
11643 -- into a FOR loop) does not attempt to remove side effects on the
11644 -- bounds again (which would cause the bounds in the index subtype
11645 -- definition to refer to temporaries before they are defined) (the
11646 -- reason is that some names are considered side effect free here
11647 -- for the subtype, but not in the context of a loop iteration
11648 -- scheme).
11669 -- The Etype of the existing Slice node is reset to this slice subtype.
11670 -- Its bounds are obtained from its first index.
11674 -- For bit-packed slice subtypes, freeze immediately (except in the case
11675 -- of being in a "spec expression" where we never freeze when we first
11676 -- see the expression).
11681 -- For all other cases insert an itype reference in the slice's actions
11682 -- so that the itype is frozen at the proper place in the tree (i.e. at
11683 -- the point where actions for the slice are analyzed). Note that this
11684 -- is different from freezing the itype immediately, which might be
11685 -- premature (e.g. if the slice is within a transient scope). This needs
11686 -- to be done only if expansion is enabled.
11693 --------------------------------
11694 -- Set_String_Literal_Subtype --
11695 --------------------------------
11703 begin
11715 -- The low bound is set from the low bound of the corresponding index
11716 -- type. Note that we do not store the high bound in the string literal
11717 -- subtype, but it can be deduced if necessary from the length and the
11718 -- low bound.
11723 -- If the lower bound is not static we create a range for the string
11724 -- literal, using the index type and the known length of the literal.
11725 -- The index type is not necessarily Positive, so the upper bound is
11726 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11728 else
11729 declare
11735 Prefix =>
11739 Left_Opnd =>
11742 Prefix =>
11744 Expressions =>
11746 Right_Opnd =>
11755 begin
11757 Set_String_Literal_Low_Bound
11760 else
11761 -- If the index type is an enumeration type, build bounds
11762 -- expression with attributes.
11764 Set_String_Literal_Low_Bound
11768 Prefix =>
11775 -- Build bona fide subtype for the string, and wrap it in an
11776 -- unchecked conversion, because the backend expects the
11777 -- String_Literal_Subtype to have a static lower bound.
11779 Index_Subtype :=
11786 -- In the context, the Index_Type may already have a constraint,
11787 -- so use common base type on string subtype. The base type may
11788 -- be used when generating attributes of the string, for example
11789 -- in the context of a slice assignment.
11814 ------------------------------
11815 -- Simplify_Type_Conversion --
11816 ------------------------------
11819 begin
11821 declare
11826 begin
11827 -- Special processing if the conversion is the expression of a
11828 -- Rounding or Truncation attribute reference. In this case we
11829 -- replace:
11831 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11833 -- by
11835 -- ityp (x)
11837 -- with the Float_Truncate flag set to False or True respectively,
11838 -- which is more efficient.
11841 and then
11847 Name_Truncation)
11848 then
11849 declare
11852 begin
11862 -----------------------------
11863 -- Unique_Fixed_Point_Type --
11864 -----------------------------
11868 -- Give error messages for true ambiguity. Messages are posted on node
11869 -- N, and entities T1, T2 are the possible interpretations.
11871 -----------------------
11872 -- Fixed_Point_Error --
11873 -----------------------
11876 begin
11882 -- Local variables
11890 -- Start of processing for Unique_Fixed_Point_Type
11892 begin
11893 -- The operations on Duration are visible, so Duration is always a
11894 -- possible interpretation.
11898 -- Look for fixed-point types in enclosing scopes
11907 then
11911 else
11922 -- Look for visible fixed type declarations in the context
11933 then
11937 else
11952 else
11953 -- When the context is a type conversion, issue the warning on the
11954 -- expression of the conversion because it is the actual operation.
11958 else
11962 Error_Msg_NE
11969 ----------------------
11970 -- Valid_Conversion --
11971 ----------------------
11973 function Valid_Conversion
11978 is
11983 function Conversion_Check
11986 -- Little routine to post Msg if Valid is False, returns Valid value
11989 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11991 procedure Conversion_Error_NE
11995 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11998 -- Return True if expression is within an instance but is not in one of
11999 -- the actuals of the instantiation. Type conversions within an instance
12000 -- are not rechecked because type visbility may lead to spurious errors,
12001 -- but conversions in an actual for a formal object must be checked.
12003 function Valid_Tagged_Conversion
12006 -- Specifically test for validity of tagged conversions
12009 -- Check index and component conformance, and accessibility levels if
12010 -- the component types are anonymous access types (Ada 2005).
12012 ----------------------
12013 -- Conversion_Check --
12014 ----------------------
12016 function Conversion_Check
12019 is
12020 begin
12021 if not Valid
12023 -- A generic unit has already been analyzed and we have verified
12024 -- that a particular conversion is OK in that context. Since the
12025 -- instance is reanalyzed without relying on the relationships
12026 -- established during the analysis of the generic, it is possible
12027 -- to end up with inconsistent views of private types. Do not emit
12028 -- the error message in such cases. The rest of the machinery in
12029 -- Valid_Conversion still ensures the proper compatibility of
12030 -- target and operand types.
12032 and then not In_Instance_Code
12033 then
12040 ------------------------
12041 -- Conversion_Error_N --
12042 ------------------------
12045 begin
12051 -------------------------
12052 -- Conversion_Error_NE --
12053 -------------------------
12055 procedure Conversion_Error_NE
12059 is
12060 begin
12066 ----------------------
12067 -- In_Instance_Code --
12068 ----------------------
12073 begin
12077 else
12081 -- The expression is part of an actual object if it appears in
12082 -- the generated object declaration in the instance.
12086 then
12089 else
12090 exit when
12099 -- Otherwise the expression appears within the instantiated unit
12105 ----------------------------
12106 -- Valid_Array_Conversion --
12107 ----------------------------
12124 begin
12125 -- Error if wrong number of dimensions
12127 if
12129 then
12130 Conversion_Error_N
12134 -- Number of dimensions matches
12136 else
12137 -- Loop through indexes of the two arrays
12145 -- Error if index types are incompatible
12151 then
12152 Conversion_Error_N
12154 Operand);
12162 -- If component types have same base type, all set
12167 -- Here if base types of components are not the same. The only
12168 -- time this is allowed is if we have anonymous access types.
12170 -- The conversion of arrays of anonymous access types can lead
12171 -- to dangling pointers. AI-392 formalizes the accessibility
12172 -- checks that must be applied to such conversions to prevent
12173 -- out-of-scope references.
12175 elsif Ekind_In
12177 E_Anonymous_Access_Subprogram_Type)
12179 and then
12181 then
12184 then
12187 Conversion_Error_N
12197 -- Conversion not allowed because of accessibility levels
12199 else
12200 Conversion_Error_N
12206 else
12210 -- All other cases where component base types do not match
12212 else
12213 Conversion_Error_N
12215 Operand);
12219 -- Check that component subtypes statically match. For numeric
12220 -- types this means that both must be either constrained or
12221 -- unconstrained. For enumeration types the bounds must match.
12222 -- All of this is checked in Subtypes_Statically_Match.
12224 if not Subtypes_Statically_Match
12226 then
12227 Conversion_Error_N
12236 -----------------------------
12237 -- Valid_Tagged_Conversion --
12238 -----------------------------
12240 function Valid_Tagged_Conversion
12243 is
12244 begin
12245 -- Upward conversions are allowed (RM 4.6(22))
12249 then
12252 -- Downward conversion are allowed if the operand is class-wide
12253 -- (RM 4.6(23)).
12257 then
12262 then
12263 return
12267 -- Ada 2005 (AI-251): The conversion to/from interface types is
12268 -- always valid. The types involved may be class-wide (sub)types.
12272 then
12275 -- If the operand is a class-wide type obtained through a limited_
12276 -- with clause, and the context includes the nonlimited view, use
12277 -- it to determine whether the conversion is legal.
12283 then
12288 then
12291 else
12292 Conversion_Error_NE
12299 -- Start of processing for Valid_Conversion
12301 begin
12305 declare
12313 begin
12314 -- Remove procedure calls, which syntactically cannot appear in
12315 -- this context, but which cannot be removed by type checking,
12316 -- because the context does not impose a type.
12318 -- The node may be labelled overloaded, but still contain only one
12319 -- interpretation because others were discarded earlier. If this
12320 -- is the case, retain the single interpretation if legal.
12328 then
12329 -- More than one candidate interpretation is available
12337 -- When compiling for a system where Address is of a visible
12338 -- integer type, spurious ambiguities can be produced when
12339 -- arithmetic operations have a literal operand and return
12340 -- System.Address or a descendant of it. These ambiguities
12341 -- are usually resolved by the context, but for conversions
12342 -- there is no context type and the removal of the spurious
12343 -- operations must be done explicitly here.
12345 if not Address_Is_Private
12347 then
12372 Conversion_Error_N
12375 -- If the interpretation involves a standard operator, use
12376 -- the location of the type, which may be user-defined.
12380 else
12384 Conversion_Error_N -- CODEFIX
12389 else
12393 Conversion_Error_N -- CODEFIX
12405 -- Deal with conversion of integer type to address if the pragma
12406 -- Allow_Integer_Address is in effect. We convert the conversion to
12407 -- an unchecked conversion in this case and we are all done.
12415 -- If we are within a child unit, check whether the type of the
12416 -- expression has an ancestor in a parent unit, in which case it
12417 -- belongs to its derivation class even if the ancestor is private.
12418 -- See RM 7.3.1 (5.2/3).
12422 -- Numeric types
12426 -- A universal fixed expression can be converted to any numeric type
12431 -- Also no need to check when in an instance or inlined body, because
12432 -- the legality has been established when the template was analyzed.
12433 -- Furthermore, numeric conversions may occur where only a private
12434 -- view of the operand type is visible at the instantiation point.
12435 -- This results in a spurious error if we check that the operand type
12436 -- is a numeric type.
12438 -- Note: in a previous version of this unit, the following tests were
12439 -- applied only for generated code (Comes_From_Source set to False),
12440 -- but in fact the test is required for source code as well, since
12441 -- this situation can arise in source code.
12446 -- Otherwise we need the conversion check
12448 else
12449 return Conversion_Check
12451 or else
12457 -- Array types
12463 then
12464 Conversion_Error_N
12468 else
12472 -- Ada 2005 (AI-251): Internally generated conversions of access to
12473 -- interface types added to force the displacement of the pointer to
12474 -- reference the corresponding dispatch table.
12479 then
12482 -- Ada 2005 (AI-251): Anonymous access types where target references an
12483 -- interface type.
12487 E_Anonymous_Access_Type)
12489 then
12490 -- Check the static accessibility rule of 4.6(17). Note that the
12491 -- check is not enforced when within an instance body, since the
12492 -- RM requires such cases to be caught at run time.
12494 -- If the operand is a rewriting of an allocator no check is needed
12495 -- because there are no accessibility issues.
12503 then
12504 -- In an instance, this is a run-time check, but one we know
12505 -- will fail, so generate an appropriate warning. The raise
12506 -- will be generated by Expand_N_Type_Conversion.
12510 Conversion_Error_N
12512 Operand);
12515 else
12516 Conversion_Error_N
12518 Operand);
12522 -- Special accessibility checks are needed in the case of access
12523 -- discriminants declared for a limited type.
12527 then
12528 -- When the operand is a selected access discriminant the check
12529 -- needs to be made against the level of the object denoted by
12530 -- the prefix of the selected name (Object_Access_Level handles
12531 -- checking the prefix of the operand for this case).
12536 then
12537 -- In an instance, this is a run-time check, but one we know
12538 -- will fail, so generate an appropriate warning. The raise
12539 -- will be generated by Expand_N_Type_Conversion.
12543 Conversion_Error_N
12548 -- Real error if not in instance body
12550 else
12551 Conversion_Error_N
12558 -- The case of a reference to an access discriminant from
12559 -- within a limited type declaration (which will appear as
12560 -- a discriminal) is always illegal because the level of the
12561 -- discriminant is considered to be deeper than any (nameable)
12562 -- access type.
12566 and then
12569 then
12570 Conversion_Error_N
12572 Operand);
12580 -- General and anonymous access types
12583 E_Anonymous_Access_Type)
12584 and then
12585 Conversion_Check
12587 and then not
12589 E_Access_Protected_Subprogram_Type),
12591 then
12594 then
12595 Conversion_Error_N
12600 -- Check the static accessibility rule of 4.6(17). Note that the
12601 -- check is not enforced when within an instance body, since the RM
12602 -- requires such cases to be caught at run time.
12607 N_Object_Declaration
12608 then
12609 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12610 -- conversions from an anonymous access type to a named general
12611 -- access type. Such conversions are not allowed in the case of
12612 -- access parameters and stand-alone objects of an anonymous
12613 -- access type. The implicit conversion case is recognized by
12614 -- testing that Comes_From_Source is False and that it's been
12615 -- rewritten. The Comes_From_Source test isn't sufficient because
12616 -- nodes in inlined calls to predefined library routines can have
12617 -- Comes_From_Source set to False. (Is there a better way to test
12618 -- for implicit conversions???)
12625 then
12628 -- Implicit conversions aren't allowed for objects of an
12629 -- anonymous access type, since such objects have nonstatic
12630 -- levels in Ada 2012.
12633 N_Object_Declaration
12634 then
12635 Conversion_Error_N
12640 -- Implicit conversions aren't allowed for anonymous access
12641 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12642 -- is done to exclude anonymous access results.
12646 N_Function_Specification,
12647 N_Procedure_Specification)
12648 then
12649 Conversion_Error_N
12654 -- This is a case where there's an enclosing object whose
12655 -- to which the "statically deeper than" relationship does
12656 -- not apply (such as an access discriminant selected from
12657 -- a dereference of an access parameter).
12661 then
12662 Conversion_Error_N
12667 -- In other cases, the level of the operand's type must be
12668 -- statically less deep than that of the target type, else
12669 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12673 then
12674 Conversion_Error_N
12683 then
12684 -- In an instance, this is a run-time check, but one we know
12685 -- will fail, so generate an appropriate warning. The raise
12686 -- will be generated by Expand_N_Type_Conversion.
12690 Conversion_Error_N
12692 Operand);
12695 -- If not in an instance body, this is a real error
12697 else
12698 -- Avoid generation of spurious error message
12701 Conversion_Error_N
12703 Operand);
12709 -- Special accessibility checks are needed in the case of access
12710 -- discriminants declared for a limited type.
12714 then
12715 -- When the operand is a selected access discriminant the check
12716 -- needs to be made against the level of the object denoted by
12717 -- the prefix of the selected name (Object_Access_Level handles
12718 -- checking the prefix of the operand for this case).
12723 then
12724 -- In an instance, this is a run-time check, but one we know
12725 -- will fail, so generate an appropriate warning. The raise
12726 -- will be generated by Expand_N_Type_Conversion.
12730 Conversion_Error_N
12735 -- If not in an instance body, this is a real error
12737 else
12738 Conversion_Error_N
12745 -- The case of a reference to an access discriminant from
12746 -- within a limited type declaration (which will appear as
12747 -- a discriminal) is always illegal because the level of the
12748 -- discriminant is considered to be deeper than any (nameable)
12749 -- access type.
12752 and then
12755 then
12756 Conversion_Error_N
12758 Operand);
12764 -- In the presence of limited_with clauses we have to use nonlimited
12765 -- views, if available.
12769 -- Helper function to handle limited views
12771 --------------------------
12772 -- Full_Designated_Type --
12773 --------------------------
12778 begin
12779 -- Handle the limited view of a type
12783 then
12785 else
12790 -- Local Declarations
12798 -- Start of processing for Check_Limited
12800 begin
12804 else
12806 Conversion_Error_NE
12811 -- Ada 2005 AI-384: legality rule is symmetric in both
12812 -- designated types. The conversion is legal (with possible
12813 -- constraint check) if either designated type is
12814 -- unconstrained.
12817 or else
12819 and then
12822 then
12823 -- Special case, if Value_Size has been used to make the
12824 -- sizes different, the conversion is not allowed even
12825 -- though the subtypes statically match.
12830 then
12831 Conversion_Error_NE
12834 Conversion_Error_NE
12839 -- Normal case where conversion is allowed
12841 else
12845 else
12846 Error_Msg_NE
12854 -- Access to subprogram types. If the operand is an access parameter,
12855 -- the type has a deeper accessibility that any master, and cannot be
12856 -- assigned. We must make an exception if the conversion is part of an
12857 -- assignment and the target is the return object of an extended return
12858 -- statement, because in that case the accessibility check takes place
12859 -- after the return.
12863 -- Note: this test of Opnd_Type is there to prevent entering this
12864 -- branch in the case of a remote access to subprogram type, which
12865 -- is internally represented as an E_Record_Type.
12868 then
12872 and then
12876 then
12877 Conversion_Error_N
12879 Operand);
12880 Conversion_Error_N
12883 Operand);
12885 Error_Msg_NE
12890 -- Check that the designated types are subtype conformant
12896 -- Check the static accessibility rule of 4.6(20)
12900 then
12901 Conversion_Error_N
12903 Operand);
12905 -- Check that if the operand type is declared in a generic body,
12906 -- then the target type must be declared within that same body
12907 -- (enforces last sentence of 4.6(20)).
12910 declare
12916 begin
12923 Conversion_Error_N
12932 -- Remote access to subprogram types
12936 then
12937 -- It is valid to convert from one RAS type to another provided
12938 -- that their specification statically match.
12940 -- Note: at this point, remote access to subprogram types have been
12941 -- expanded to their E_Record_Type representation, and we need to
12942 -- go back to the original access type definition using the
12943 -- Corresponding_Remote_Type attribute in order to check that the
12944 -- designated profiles match.
12949 Check_Subtype_Conformant
12952 Old_Id =>
12954 Err_Loc =>
12955 N);
12958 -- If it was legal in the generic, it's legal in the instance
12963 -- If both are tagged types, check legality of view conversions
12966 and then
12968 then
12971 -- Types derived from the same root type are convertible
12976 -- In an instance or an inlined body, there may be inconsistent views of
12977 -- the same type, or of types derived from a common root.
12980 and then
12983 then
12986 -- Special check for common access type error case
12990 then
12992 Conversion_Error_NE -- CODEFIX
12996 -- Here we have a real conversion error
12998 else
12999 Conversion_Error_NE