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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.
4841 and then not In_Instance_Body
4842 then
4845 Error_Msg_N
4848 else
4849 Error_Msg_N
4857 -- A qualified expression requires an exact match of the type. Class-
4858 -- wide matching is not allowed.
4863 then
4867 -- Calls to build-in-place functions are not currently supported in
4868 -- allocators for access types associated with a simple storage pool.
4869 -- Supporting such allocators may require passing additional implicit
4870 -- parameters to build-in-place functions (or a significant revision
4871 -- of the current b-i-p implementation to unify the handling for
4872 -- multiple kinds of storage pools). ???
4876 then
4877 declare
4880 begin
4882 and then
4883 Present (Get_Rep_Pragma
4885 then
4886 Error_Msg_N
4893 -- A special accessibility check is needed for allocators that
4894 -- constrain access discriminants. The level of the type of the
4895 -- expression used to constrain an access discriminant cannot be
4896 -- deeper than the type of the allocator (in contrast to access
4897 -- parameters, where the level of the actual can be arbitrary).
4899 -- We can't use Valid_Conversion to perform this check because in
4900 -- general the type of the allocator is unrelated to the type of
4901 -- the access discriminant.
4905 then
4912 then
4915 -- Get the first component expression of the aggregate
4925 else
4929 else
4948 else
4953 else
4962 -- For a subtype mark or subtype indication, freeze the subtype
4964 else
4968 Error_Msg_N
4972 -- A special accessibility check is needed for allocators that
4973 -- constrain access discriminants. The level of the type of the
4974 -- expression used to constrain an access discriminant cannot be
4975 -- deeper than the type of the allocator (in contrast to access
4976 -- parameters, where the level of the actual can be arbitrary).
4977 -- We can't use Valid_Conversion to perform this check because
4978 -- in general the type of the allocator is unrelated to the type
4979 -- of the access discriminant.
4984 then
4994 else
5008 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5009 -- check that the level of the type of the created object is not deeper
5010 -- than the level of the allocator's access type, since extensions can
5011 -- now occur at deeper levels than their ancestor types. This is a
5012 -- static accessibility level check; a run-time check is also needed in
5013 -- the case of an initialized allocator with a class-wide argument (see
5014 -- Expand_Allocator_Expression).
5018 then
5019 declare
5022 begin
5027 else
5033 then
5036 Error_Msg_N
5045 -- Do not apply Ada 2005 accessibility checks on a class-wide
5046 -- allocator if the type given in the allocator is a formal
5047 -- type. A run-time check will be performed in the instance.
5057 -- Check for allocation from an empty storage pool
5062 -- If the context is an unchecked conversion, as may happen within an
5063 -- inlined subprogram, the allocator is being resolved with its own
5064 -- anonymous type. In that case, if the target type has a specific
5065 -- storage pool, it must be inherited explicitly by the allocator type.
5069 then
5070 Set_Associated_Storage_Pool
5078 -- Check that an allocator with task parts isn't for a nested access
5079 -- type when restriction No_Task_Hierarchy applies.
5083 then
5087 -- An illegal allocator may be rewritten as a raise Program_Error
5088 -- statement.
5092 -- An anonymous access discriminant is the definition of a
5093 -- coextension.
5097 N_Discriminant_Specification
5098 then
5099 declare
5103 begin
5106 -- Ada 2012 AI05-0052: If the designated type of the allocator
5107 -- is limited, then the allocator shall not be used to define
5108 -- the value of an access discriminant unless the discriminated
5109 -- type is immutably limited.
5114 then
5115 Error_Msg_N
5121 -- Avoid marking an allocator as a dynamic coextension if it is
5122 -- within a static construct.
5128 -- Cleanup for potential static coextensions
5130 else
5136 -- Report a simple error: if the designated object is a local task,
5137 -- its body has not been seen yet, and its activation will fail an
5138 -- elaboration check.
5145 then
5151 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5152 -- type with a task component on a subpool. This action must raise
5153 -- Program_Error at runtime.
5159 then
5171 ---------------------------
5172 -- Resolve_Arithmetic_Op --
5173 ---------------------------
5175 -- Used for resolving all arithmetic operators except exponentiation
5186 -- We do the resolution using the base type, because intermediate values
5187 -- in expressions always are of the base type, not a subtype of it.
5190 -- Returns True if N is in a context that expects "any real type"
5193 -- Return True iff given type is Integer or universal real/integer
5196 -- Choose type of integer literal in fixed-point operation to conform
5197 -- to available fixed-point type. T is the type of the other operand,
5198 -- which is needed to determine the expected type of N.
5201 -- Set operand type to T if universal
5203 -------------------------------
5204 -- Expected_Type_Is_Any_Real --
5205 -------------------------------
5208 begin
5209 -- N is the expression after "delta" in a fixed_point_definition;
5210 -- see RM-3.5.9(6):
5213 N_Decimal_Fixed_Point_Definition,
5215 -- N is one of the bounds in a real_range_specification;
5216 -- see RM-3.5.7(5):
5218 N_Real_Range_Specification,
5220 -- N is the expression of a delta_constraint;
5221 -- see RM-J.3(3):
5223 N_Delta_Constraint);
5226 -----------------------------
5227 -- Is_Integer_Or_Universal --
5228 -----------------------------
5235 begin
5241 else
5247 then
5258 ----------------------------
5259 -- Set_Mixed_Mode_Operand --
5260 ----------------------------
5266 begin
5269 -- A universal integer literal is resolved as standard integer
5270 -- except in the case of a fixed-point result, where we leave it
5271 -- as universal (to be handled by Exp_Fixd later on)
5275 else
5283 then
5284 -- A universal real can appear in a fixed-type context. We resolve
5285 -- the literal with that context, even though this might raise an
5286 -- exception prematurely (the other operand may be zero).
5293 then
5294 -- Integer arg in mixed-mode operation. Resolve with universal
5295 -- type, in case preference rule must be applied.
5301 then
5302 -- Not a mixed-mode operation, resolve with context
5308 -- N may itself be a mixed-mode operation, so use context type
5315 then
5316 -- Must be (fixed * fixed) operation, operand must have one
5317 -- compatible interpretation.
5324 then
5325 -- C * F(X) in a fixed context, where C is a real literal or a
5326 -- fixed-point expression. F must have either a fixed type
5327 -- interpretation or an integer interpretation, but not both.
5334 else
5341 else
5349 -- Reanalyze the literal with the fixed type of the context. If
5350 -- context is Universal_Fixed, we are within a conversion, leave
5351 -- the literal as a universal real because there is no usable
5352 -- fixed type, and the target of the conversion plays no role in
5353 -- the resolution.
5355 declare
5359 begin
5362 else
5368 then
5370 else
5378 -- A universal real conditional expression can appear in a fixed-type
5379 -- context and must be resolved with that context to facilitate the
5380 -- code generation to the backend.
5385 then
5388 else
5393 ----------------------
5394 -- Set_Operand_Type --
5395 ----------------------
5398 begin
5401 then
5406 -- Start of processing for Resolve_Arithmetic_Op
5408 begin
5413 then
5417 -- Special-case for mixed-mode universal expressions or fixed point type
5418 -- operation: each argument is resolved separately. The same treatment
5419 -- is required if one of the operands of a fixed point operation is
5420 -- universal real, since in this case we don't do a conversion to a
5421 -- specific fixed-point type (instead the expander handles the case).
5423 -- Set the type of the node to its universal interpretation because
5424 -- legality checks on an exponentiation operand need the context.
5429 then
5440 or else
5443 then
5448 -- If context is a fixed type and one operand is integer, the other
5449 -- is resolved with the type of the context.
5454 then
5461 then
5465 -- If both operands are universal and the context is a floating
5466 -- point type, the operands are resolved to the type of the context.
5472 else
5477 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5478 -- multiplying operators from being used when the expected type is
5479 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5480 -- some cases where the expected type is actually Any_Real;
5481 -- Expected_Type_Is_Any_Real takes care of that case.
5485 then
5489 N_Unchecked_Type_Conversion)
5490 then
5497 else
5500 and then not
5502 N_Unchecked_Type_Conversion)
5503 then
5504 Error_Msg_N
5509 -- The expected type is "any real type" in contexts like
5511 -- type T is delta <universal_fixed-expression> ...
5513 -- in which case we need to set the type to Universal_Real
5514 -- so that static expression evaluation will work properly.
5518 else
5528 then
5533 -- If no previous errors, this is only possible if one operand is
5534 -- overloaded and the context is universal. Resolve as such.
5539 else
5541 and then
5543 then
5547 -- If the context is Universal_Fixed and the operands are also
5548 -- universal fixed, this is an error, unless there is only one
5549 -- applicable fixed_point type (usually Duration).
5557 else
5562 else
5567 -- If one of the arguments was resolved to a non-universal type.
5568 -- label the result of the operation itself with the same type.
5569 -- Do the same for the universal argument, if any.
5581 -- In SPARK, a multiplication or division with operands of fixed point
5582 -- types must be qualified or explicitly converted to identify the
5583 -- result type.
5588 and then
5590 then
5591 Check_SPARK_05_Restriction
5595 -- Set overflow and division checking bit
5602 -- Give warning if explicit division by zero
5606 then
5612 or else
5615 then
5616 -- Specialize the warning message according to the operation.
5617 -- When SPARK_Mode is On, force a warning instead of an error
5618 -- in that case, as this likely corresponds to deactivated
5619 -- code. The following warnings are for the case
5624 -- For division, we have two cases, for float division
5625 -- of an unconstrained float type, on a machine where
5626 -- Machine_Overflows is false, we don't get an exception
5627 -- at run-time, but rather an infinity or Nan. The Nan
5628 -- case is pretty obscure, so just warn about infinities.
5632 and then not Machine_Overflows_On_Target
5633 then
5634 Error_Msg_N
5638 -- For all other cases, we get a Constraint_Error
5640 else
5641 Apply_Compile_Time_Constraint_Error
5648 Apply_Compile_Time_Constraint_Error
5654 Apply_Compile_Time_Constraint_Error
5659 -- Division by zero can only happen with division, rem,
5660 -- and mod operations.
5666 -- In GNATprove mode, we enable the division check so that
5667 -- GNATprove will issue a message if it cannot be proved.
5673 -- Otherwise just set the flag to check at run time
5675 else
5680 -- If Restriction No_Implicit_Conditionals is active, then it is
5681 -- violated if either operand can be negative for mod, or for rem
5682 -- if both operands can be negative.
5686 then
5687 declare
5694 -- Set if corresponding operand might be negative
5696 begin
5697 Determine_Range
5701 Determine_Range
5705 -- Check if we will be generating conditionals. There are two
5706 -- cases where that can happen, first for REM, the only case
5707 -- is largest negative integer mod -1, where the division can
5708 -- overflow, but we still have to give the right result. The
5709 -- front end generates a test for this annoying case. Here we
5710 -- just test if both operands can be negative (that's what the
5711 -- expander does, so we match its logic here).
5713 -- The second case is mod where either operand can be negative.
5714 -- In this case, the back end has to generate additional tests.
5717 or else
5719 then
5730 ------------------
5731 -- Resolve_Call --
5732 ------------------
5735 function Same_Or_Aliased_Subprograms
5738 -- Returns True if the subprogram entity S is the same as E or else
5739 -- S is an alias of E.
5741 ---------------------------------
5742 -- Same_Or_Aliased_Subprograms --
5743 ---------------------------------
5745 function Same_Or_Aliased_Subprograms
5748 is
5750 begin
5754 -- Local variables
5768 -- Start of processing for Resolve_Call
5770 begin
5771 -- Preserve relevant elaboration-related attributes of the context which
5772 -- are no longer available or very expensive to recompute once analysis,
5773 -- resolution, and expansion are over.
5775 Mark_Elaboration_Attributes
5780 -- The context imposes a unique interpretation with type Typ on a
5781 -- procedure or function call. Find the entity of the subprogram that
5782 -- yields the expected type, and propagate the corresponding formal
5783 -- constraints on the actuals. The caller has established that an
5784 -- interpretation exists, and emitted an error if not unique.
5786 -- First deal with the case of a call to an access-to-subprogram,
5787 -- dereference made explicit in Analyze_Call.
5793 else
5794 -- Find the interpretation whose type (a subprogram type) has a
5795 -- return type that is compatible with the context. Analysis of
5796 -- the node has established that one exists.
5815 -- If the prefix is not an entity, then resolve it
5821 -- For an indirect call, we always invalidate checks, since we do not
5822 -- know whether the subprogram is local or global. Yes we could do
5823 -- better here, e.g. by knowing that there are no local subprograms,
5824 -- but it does not seem worth the effort. Similarly, we kill all
5825 -- knowledge of current constant values.
5827 Kill_Current_Values;
5829 -- If this is a procedure call which is really an entry call, do
5830 -- the conversion of the procedure call to an entry call. Protected
5831 -- operations use the same circuitry because the name in the call
5832 -- can be an arbitrary expression with special resolution rules.
5837 then
5840 -- Annotate the tree by creating a call marker in case the original
5841 -- call is transformed by expansion. The call marker is automatically
5842 -- saved for later examination by the ABE Processing phase.
5846 -- Kill checks and constant values, as above for indirect case
5847 -- Who knows what happens when another task is activated?
5849 Kill_Current_Values;
5852 -- Normal subprogram call with name established in Resolve
5858 -- Otherwise we must have the case of an overloaded call
5860 else
5863 -- Initialize Nam to prevent warning (we know it will be assigned
5864 -- in the loop below, but the compiler does not know that).
5884 then
5885 -- The prefix is a parameterless function call that returns an access
5886 -- to subprogram. If parameters are present in the current call, add
5887 -- add an explicit dereference. We use the base type here because
5888 -- within an instance these may be subtypes.
5890 -- The dereference is added either in Analyze_Call or here. Should
5891 -- be consolidated ???
5900 -- Check that a call to Current_Task does not occur in an entry body
5903 declare
5906 begin
5908 loop
5911 -- Exclude calls that occur within the default of a formal
5912 -- parameter of the entry, since those are evaluated outside
5913 -- of the body.
5920 then
5923 Error_Msg_NE
5937 -- Check that a procedure call does not occur in the context of the
5938 -- entry call statement of a conditional or timed entry call. Note that
5939 -- the case of a call to a subprogram renaming of an entry will also be
5940 -- rejected. The test for N not being an N_Entry_Call_Statement is
5941 -- defensive, covering the possibility that the processing of entry
5942 -- calls might reach this point due to later modifications of the code
5943 -- above.
5948 then
5952 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5953 -- for a procedure_or_entry_call, the procedure_name or
5954 -- procedure_prefix of the procedure_call_statement shall denote
5955 -- an entry renamed by a procedure, or (a view of) a primitive
5956 -- subprogram of a limited interface whose first parameter is
5957 -- a controlling parameter.
5962 then
5963 Error_Msg_N
5968 -- If the SPARK_05 restriction is active, we are not allowed
5969 -- to have a call to a subprogram before we see its completion.
5974 -- Don't flag strange internal calls
5979 -- Only flag calls in extended main source
5984 -- Exclude enumeration literals from this processing
5987 then
5988 Check_SPARK_05_Restriction
5992 -- Check that this is not a call to a protected procedure or entry from
5993 -- within a protected function.
5997 -- Freeze the subprogram name if not in a spec-expression. Note that
5998 -- we freeze procedure calls as well as function calls. Procedure calls
5999 -- are not frozen according to the rules (RM 13.14(14)) because it is
6000 -- impossible to have a procedure call to a non-frozen procedure in
6001 -- pure Ada, but in the code that we generate in the expander, this
6002 -- rule needs extending because we can generate procedure calls that
6003 -- need freezing.
6005 -- In Ada 2012, expression functions may be called within pre/post
6006 -- conditions of subsequent functions or expression functions. Such
6007 -- calls do not freeze when they appear within generated bodies,
6008 -- (including the body of another expression function) which would
6009 -- place the freeze node in the wrong scope. An expression function
6010 -- is frozen in the usual fashion, by the appearance of a real body,
6011 -- or at the end of a declarative part.
6014 and then not In_Spec_Expression
6016 and then
6019 then
6023 -- For a predefined operator, the type of the result is the type imposed
6024 -- by context, except for a predefined operation on universal fixed.
6025 -- Otherwise The type of the call is the type returned by the subprogram
6026 -- being called.
6033 -- If the subprogram returns an array type, and the context requires the
6034 -- component type of that array type, the node is really an indexing of
6035 -- the parameterless call. Resolve as such. A pathological case occurs
6036 -- when the type of the component is an access to the array type. In
6037 -- this case the call is truly ambiguous. If the call is to an intrinsic
6038 -- subprogram, it can't be an indexed component. This check is necessary
6039 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6040 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6041 -- pointers to the same array), the compiler gets confused and does an
6042 -- infinite recursion.
6045 and then
6048 or else
6051 and then
6054 then
6055 declare
6060 begin
6063 then
6064 Error_Msg_N
6066 else
6069 -- The called entity may be an explicit dereference, in which
6070 -- case there is no entity to set.
6078 or else
6080 and then
6082 then
6085 -- Indexed call to a parameterless function
6087 Index_Node :=
6089 Prefix =>
6092 else
6093 -- An Ada 2005 prefixed call to a primitive operation
6094 -- whose first parameter is the prefix. This prefix was
6095 -- prepended to the parameter list, which is actually a
6096 -- list of indexes. Remove the prefix in order to build
6097 -- the proper indexed component.
6099 Index_Node :=
6101 Prefix =>
6104 Parameter_Associations =>
6105 New_List
6110 -- Preserve the parenthesis count of the node
6114 -- Since we are correcting a node classification error made
6115 -- by the parser, we call Replace rather than Rewrite.
6123 -- Annotate the tree by creating a call marker in case
6124 -- the original call is transformed by expansion. The call
6125 -- marker is automatically saved for later examination by
6126 -- the ABE Processing phase.
6135 else
6136 -- If the called function is not declared in the main unit and it
6137 -- returns the limited view of type then use the available view (as
6138 -- is done in Try_Object_Operation) to prevent back-end confusion;
6139 -- for the function entity itself. The call must appear in a context
6140 -- where the nonlimited view is available. If the function entity is
6141 -- in the extended main unit then no action is needed, because the
6142 -- back end handles this case. In either case the type of the call
6143 -- is the nonlimited view.
6147 then
6154 else
6159 -- In the case where the call is to an overloaded subprogram, Analyze
6160 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6161 -- such a case Normalize_Actuals needs to be called once more to order
6162 -- the actuals correctly. Otherwise the call will have the ordering
6163 -- given by the last overloaded subprogram whether this is the correct
6164 -- one being called or not.
6171 -- In any case, call is fully resolved now. Reset Overload flag, to
6172 -- prevent subsequent overload resolution if node is analyzed again
6177 -- A Ghost entity must appear in a specific context
6183 -- If we are calling the current subprogram from immediately within its
6184 -- body, then that is the case where we can sometimes detect cases of
6185 -- infinite recursion statically. Do not try this in case restriction
6186 -- No_Recursion is in effect anyway, and do it only for source calls.
6191 -- Check violation of SPARK_05 restriction which does not permit
6192 -- a subprogram body to contain a call to the subprogram directly.
6196 then
6197 Check_SPARK_05_Restriction
6201 -- Issue warning for possible infinite recursion in the absence
6202 -- of the No_Recursion restriction.
6207 then
6208 -- Here we detected and flagged an infinite recursion, so we do
6209 -- not need to test the case below for further warnings. Also we
6210 -- are all done if we now have a raise SE node.
6216 -- If call is to immediately containing subprogram, then check for
6217 -- the case of a possible run-time detectable infinite recursion.
6219 else
6223 -- Although in general case, recursion is not statically
6224 -- checkable, the case of calling an immediately containing
6225 -- subprogram is easy to catch.
6229 -- If the recursive call is to a parameterless subprogram,
6230 -- then even if we can't statically detect infinite
6231 -- recursion, this is pretty suspicious, and we output a
6232 -- warning. Furthermore, we will try later to detect some
6233 -- cases here at run time by expanding checking code (see
6234 -- Detect_Infinite_Recursion in package Exp_Ch6).
6236 -- If the recursive call is within a handler, do not emit a
6237 -- warning, because this is a common idiom: loop until input
6238 -- is correct, catch illegal input in handler and restart.
6244 then
6245 -- For the case of a procedure call. We give the message
6246 -- only if the call is the first statement in a sequence
6247 -- of statements, or if all previous statements are
6248 -- simple assignments. This is simply a heuristic to
6249 -- decrease false positives, without losing too many good
6250 -- warnings. The idea is that these previous statements
6251 -- may affect global variables the procedure depends on.
6252 -- We also exclude raise statements, that may arise from
6253 -- constraint checks and are probably unrelated to the
6254 -- intended control flow.
6258 then
6259 declare
6261 begin
6265 N_Raise_Constraint_Error)
6266 then
6275 -- Do not give warning if we are in a conditional context
6277 declare
6279 begin
6285 then
6290 -- Here warning is to be issued
6306 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6310 -- If subprogram name is a predefined operator, it was given in
6311 -- functional notation. Replace call node with operator node, so
6312 -- that actuals can be resolved appropriately.
6320 then
6326 -- Create a transient scope if the resulting type requires it
6328 -- There are several notable exceptions:
6330 -- a) In init procs, the transient scope overhead is not needed, and is
6331 -- even incorrect when the call is a nested initialization call for a
6332 -- component whose expansion may generate adjust calls. However, if the
6333 -- call is some other procedure call within an initialization procedure
6334 -- (for example a call to Create_Task in the init_proc of the task
6335 -- run-time record) a transient scope must be created around this call.
6337 -- b) Enumeration literal pseudo-calls need no transient scope
6339 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6340 -- functions) do not use the secondary stack even though the return
6341 -- type may be unconstrained.
6343 -- d) Calls to a build-in-place function, since such functions may
6344 -- allocate their result directly in a target object, and cases where
6345 -- the result does get allocated in the secondary stack are checked for
6346 -- within the specialized Exp_Ch6 procedures for expanding those
6347 -- build-in-place calls.
6349 -- e) Calls to inlinable expression functions do not use the secondary
6350 -- stack (since the call will be replaced by its returned object).
6352 -- f) If the subprogram is marked Inline_Always, then even if it returns
6353 -- an unconstrained type the call does not require use of the secondary
6354 -- stack. However, inlining will only take place if the body to inline
6355 -- is already present. It may not be available if e.g. the subprogram is
6356 -- declared in a child instance.
6358 -- If this is an initialization call for a type whose construction
6359 -- uses the secondary stack, and it is not a nested call to initialize
6360 -- a component, we do need to create a transient scope for it. We
6361 -- check for this by traversing the type in Check_Initialization_Call.
6367 then
6374 then
6377 elsif Expander_Active
6380 and then
6382 or else
6384 then
6387 -- If the call appears within the bounds of a loop, it will
6388 -- be rewritten and reanalyzed, nothing left to do here.
6395 and then not Within_Init_Proc
6396 then
6400 -- A protected function cannot be called within the definition of the
6401 -- enclosing protected type, unless it is part of a pre/postcondition
6402 -- on another protected operation. This may appear in the entry wrapper
6403 -- created for an entry with preconditions.
6408 and then not In_Spec_Expression
6410 then
6411 Error_Msg_NE
6415 -- Propagate interpretation to actuals, and add default expressions
6416 -- where needed.
6421 -- Overloaded literals are rewritten as function calls, for purpose of
6422 -- resolution. After resolution, we can replace the call with the
6423 -- literal itself.
6429 -- Avoid validation, since it is a static function call
6435 -- If the subprogram is not global, then kill all saved values and
6436 -- checks. This is a bit conservative, since in many cases we could do
6437 -- better, but it is not worth the effort. Similarly, we kill constant
6438 -- values. However we do not need to do this for internal entities
6439 -- (unless they are inherited user-defined subprograms), since they
6440 -- are not in the business of molesting local values.
6442 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6443 -- kill all checks and values for calls to global subprograms. This
6444 -- takes care of the case where an access to a local subprogram is
6445 -- taken, and could be passed directly or indirectly and then called
6446 -- from almost any context.
6448 -- Note: we do not do this step till after resolving the actuals. That
6449 -- way we still take advantage of the current value information while
6450 -- scanning the actuals.
6452 -- We suppress killing values if we are processing the nodes associated
6453 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6454 -- type kills all the values as part of analyzing the code that
6455 -- initializes the dispatch tables.
6459 or else Suppress_Value_Tracking_On_Call
6464 then
6465 Kill_Current_Values;
6468 -- If we are warning about unread OUT parameters, this is the place to
6469 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6470 -- after the above call to Kill_Current_Values (since that call clears
6471 -- the Last_Assignment field of all local variables).
6476 then
6477 declare
6481 begin
6491 then
6501 -- If the subprogram is a primitive operation, check whether or not
6502 -- it is a correct dispatching call.
6506 then
6511 and then not In_Instance
6512 then
6516 -- If this is a dispatching call, generate the appropriate reference,
6517 -- for better source navigation in GPS.
6521 then
6524 -- Normal case, not a dispatching call: generate a call reference
6526 else
6534 -- Check for violation of restriction No_Specific_Termination_Handlers
6535 -- and warn on a potentially blocking call to Abort_Task.
6539 or else
6541 then
6548 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6549 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6550 -- need to check the second argument to determine whether it is an
6551 -- absolute or relative timing event.
6556 then
6560 -- Issue an error for a call to an eliminated subprogram. This routine
6561 -- will not perform the check if the call appears within a default
6562 -- expression.
6566 -- In formal mode, the primitive operations of a tagged type or type
6567 -- extension do not include functions that return the tagged type.
6573 then
6577 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6578 -- class-wide and the call dispatches on result in a context that does
6579 -- not provide a tag, the call raises Program_Error.
6582 and then In_Instance
6587 then
6588 -- Verify that none of the formals are controlling
6590 declare
6594 begin
6616 -- Check for calling a function with OUT or IN OUT parameter when the
6617 -- calling context (us right now) is not Ada 2012, so does not allow
6618 -- OUT or IN OUT parameters in function calls. Functions declared in
6619 -- a predefined unit are OK, as they may be called indirectly from a
6620 -- user-declared instantiation.
6626 then
6631 -- Check the dimensions of the actuals in the call. For function calls,
6632 -- propagate the dimensions from the returned type to N.
6636 -- All done, evaluate call and deal with elaboration issues
6640 -- Annotate the tree by creating a call marker in case the original call
6641 -- is transformed by expansion. The call marker is automatically saved
6642 -- for later examination by the ABE Processing phase.
6646 -- In GNATprove mode, expansion is disabled, but we want to inline some
6647 -- subprograms to facilitate formal verification. Indirect calls through
6648 -- a subprogram type or within a generic cannot be inlined. Inlining is
6649 -- performed only for calls subject to SPARK_Mode on.
6651 if GNATprove_Mode
6654 and then not Inside_A_Generic
6655 then
6662 -- Nothing to do if the subprogram is not eligible for inlining in
6663 -- GNATprove mode, or inlining is disabled with switch -gnatdm
6667 or else Debug_Flag_M
6668 then
6671 -- Calls cannot be inlined inside assertions, as GNATprove treats
6672 -- assertions as logic expressions. Only issue a message when the
6673 -- body has been seen, otherwise this leads to spurious messages
6674 -- on expression functions.
6678 Cannot_Inline
6682 -- Calls cannot be inlined inside default expressions
6685 Cannot_Inline
6688 -- Inlining should not be performed during pre-analysis
6692 -- Do not inline calls inside expression functions, as this
6693 -- would prevent interpreting them as logical formulas in
6694 -- GNATprove. Only issue a message when the body has been seen,
6695 -- otherwise this leads to spurious messages on callees that
6696 -- are themselves expression functions.
6699 and then Is_Expression_Function_Or_Completion
6701 then
6704 then
6705 Cannot_Inline
6710 -- With the one-pass inlining technique, a call cannot be
6711 -- inlined if the corresponding body has not been seen yet.
6714 Cannot_Inline
6717 -- Nothing to do if there is no body to inline, indicating that
6718 -- the subprogram is not suitable for inlining in GNATprove
6719 -- mode.
6724 -- Calls cannot be inlined inside potentially unevaluated
6725 -- expressions, as this would create complex actions inside
6726 -- expressions, that are not handled by GNATprove.
6729 Cannot_Inline
6733 -- Do not inline calls which would possibly lead to missing a
6734 -- type conversion check on an input parameter.
6737 Cannot_Inline
6741 -- Otherwise, inline the call
6743 else
6755 -----------------------------
6756 -- Resolve_Case_Expression --
6757 -----------------------------
6765 begin
6777 -- When the expression is of a scalar subtype different from the
6778 -- result subtype, then insert a conversion to ensure the generation
6779 -- of a constraint check.
6789 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6790 -- dynamically tagged must be known statically.
6798 Error_Msg_N
6812 -------------------------------
6813 -- Resolve_Character_Literal --
6814 -------------------------------
6820 begin
6821 -- Verify that the character does belong to the type of the context
6826 -- Wide_Wide_Character literals must always be defined, since the set
6827 -- of wide wide character literals is complete, i.e. if a character
6828 -- literal is accepted by the parser, then it is OK for wide wide
6829 -- character (out of range character literals are rejected).
6834 -- Always accept character literal for type Any_Character, which
6835 -- occurs in error situations and in comparisons of literals, both
6836 -- of which should accept all literals.
6841 -- For Standard.Character or a type derived from it, check that the
6842 -- literal is in range.
6849 -- For Standard.Wide_Character or a type derived from it, check that the
6850 -- literal is in range.
6857 -- If the entity is already set, this has already been resolved in a
6858 -- generic context, or comes from expansion. Nothing else to do.
6863 -- Otherwise we have a user defined character type, and we can use the
6864 -- standard visibility mechanisms to locate the referenced entity.
6866 else
6879 -- If we fall through, then the literal does not match any of the
6880 -- entries of the enumeration type. This isn't just a constraint error
6881 -- situation, it is an illegality (see RM 4.2).
6883 Error_Msg_NE
6887 ---------------------------
6888 -- Resolve_Comparison_Op --
6889 ---------------------------
6891 -- Context requires a boolean type, and plays no role in resolution.
6892 -- Processing identical to that for equality operators. The result type is
6893 -- the base type, which matters when pathological subtypes of booleans with
6894 -- limited ranges are used.
6901 begin
6902 -- If this is an intrinsic operation which is not predefined, use the
6903 -- types of its declared arguments to resolve the possibly overloaded
6904 -- operands. Otherwise the operands are unambiguous and specify the
6905 -- expected type.
6910 else
6921 -- Skip remaining processing if already set to Any_Type
6927 -- Deal with other error cases
6931 T = Any_Character
6932 then
6935 else
6943 -- Resolve the operands if types OK
6952 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6953 -- types or array types except String.
6956 Check_SPARK_05_Restriction
6961 then
6962 Check_SPARK_05_Restriction
6966 -- Check comparison on unordered enumeration
6970 Error_Msg_NE
6977 -- Evaluate the relation (note we do this after the above check since
6978 -- this Eval call may change N to True/False. Skip this evaluation
6979 -- inside assertions, in order to keep assertions as written by users
6980 -- for tools that rely on these, e.g. GNATprove for loop invariants.
6981 -- Except evaluation is still performed even inside assertions for
6982 -- comparisons between values of universal type, which are useless
6983 -- for static analysis tools, and not supported even by GNATprove.
6987 and then
6989 then
6994 -----------------------------------------
6995 -- Resolve_Discrete_Subtype_Indication --
6996 -----------------------------------------
6998 procedure Resolve_Discrete_Subtype_Indication
7001 is
7005 begin
7013 else
7023 Error_Msg_NE
7026 -- Rewrite the constraint as a range of Typ
7027 -- to allow compilation to proceed further.
7039 else
7043 -- Additionally, we must check that the bounds are compatible
7044 -- with the given subtype, which might be different from the
7045 -- type of the context.
7049 -- ??? If the above check statically detects a Constraint_Error
7050 -- it replaces the offending bound(s) of the range R with a
7051 -- Constraint_Error node. When the itype which uses these bounds
7052 -- is frozen the resulting call to Duplicate_Subexpr generates
7053 -- a new temporary for the bounds.
7055 -- Unfortunately there are other itypes that are also made depend
7056 -- on these bounds, so when Duplicate_Subexpr is called they get
7057 -- a forward reference to the newly created temporaries and Gigi
7058 -- aborts on such forward references. This is probably sign of a
7059 -- more fundamental problem somewhere else in either the order of
7060 -- itype freezing or the way certain itypes are constructed.
7062 -- To get around this problem we call Remove_Side_Effects right
7063 -- away if either bounds of R are a Constraint_Error.
7065 declare
7069 begin
7085 -------------------------
7086 -- Resolve_Entity_Name --
7087 -------------------------
7089 -- Used to resolve identifiers and expanded names
7092 function Is_Assignment_Or_Object_Expression
7095 -- Determine whether node Context denotes an assignment statement or an
7096 -- object declaration whose expression is node Expr.
7098 ----------------------------------------
7099 -- Is_Assignment_Or_Object_Expression --
7100 ----------------------------------------
7102 function Is_Assignment_Or_Object_Expression
7105 is
7106 begin
7108 N_Object_Declaration)
7110 then
7113 -- Check whether a construct that yields a name is the expression of
7114 -- an assignment statement or an object declaration.
7117 N_Explicit_Dereference,
7118 N_Indexed_Component,
7119 N_Selected_Component,
7120 N_Slice)
7122 or else
7124 N_Unchecked_Type_Conversion)
7126 then
7127 return
7128 Is_Assignment_Or_Object_Expression
7132 -- Otherwise the context is not an assignment statement or an object
7133 -- declaration.
7135 else
7140 -- Local variables
7145 -- Start of processing for Resolve_Entity_Name
7147 begin
7148 -- If garbage from errors, set to Any_Type and return
7155 -- Replace named numbers by corresponding literals. Note that this is
7156 -- the one case where Resolve_Entity_Name must reset the Etype, since
7157 -- it is currently marked as universal.
7167 -- For enumeration literals, we need to make sure that a proper style
7168 -- check is done, since such literals are overloaded, and thus we did
7169 -- not do a style check during the first phase of analysis.
7175 -- Case of (sub)type name appearing in a context where an expression
7176 -- is expected. This is legal if occurrence is a current instance.
7177 -- See RM 8.6 (17/3).
7183 -- Any other use is an error
7185 else
7186 Error_Msg_N
7190 -- Check discriminant use if entity is discriminant in current scope,
7191 -- i.e. discriminant of record or concurrent type currently being
7192 -- analyzed. Uses in corresponding body are unrestricted.
7197 then
7200 -- A parameterless generic function cannot appear in a context that
7201 -- requires resolution.
7206 -- In Ada 83 an OUT parameter cannot be read
7211 or else Is_Assignment_Or_Object_Expression
7214 then
7219 -- In all other cases, just do the possible static evaluation
7221 else
7222 -- A deferred constant that appears in an expression must have a
7223 -- completion, unless it has been removed by in-place expansion of
7224 -- an aggregate. A constant that is a renaming does not need
7225 -- initialization.
7231 and then not In_Spec_Expression
7234 then
7238 then
7240 else
7241 Error_Msg_N
7251 -- When the entity appears in a parameter association, retrieve the
7252 -- related subprogram call.
7260 -- The following checks are only relevant when SPARK_Mode is on as
7261 -- they are not standard Ada legality rules.
7265 -- An effectively volatile object subject to enabled properties
7266 -- Async_Writers or Effective_Reads must appear in non-interfering
7267 -- context (SPARK RM 7.1.3(12)).
7274 then
7275 SPARK_Msg_N
7280 -- The variable may eventually become a constituent of a single
7281 -- protected/task type. Record the reference now and verify its
7282 -- legality when analyzing the contract of the variable
7283 -- (SPARK RM 9.3).
7290 -- A Ghost entity must appear in a specific context
7300 -------------------
7301 -- Resolve_Entry --
7302 -------------------
7314 -- If the bounds of the entry family being called depend on task
7315 -- discriminants, build a new index subtype where a discriminant is
7316 -- replaced with the value of the discriminant of the target task.
7317 -- The target task is the prefix of the entry name in the call.
7319 -----------------------
7320 -- Actual_Index_Type --
7321 -----------------------
7331 -- If the bound is given by a discriminant, replace with a reference
7332 -- to the discriminant of the same name in the target task. If the
7333 -- entry name is the target of a requeue statement and the entry is
7334 -- in the current protected object, the bound to be used is the
7335 -- discriminal of the object (see Apply_Range_Checks for details of
7336 -- the transformation).
7338 -----------------------------
7339 -- Actual_Discriminant_Ref --
7340 -----------------------------
7346 begin
7351 then
7357 then
7358 -- Note: here Bound denotes a discriminant of the corresponding
7359 -- record type tskV, whose discriminal is a formal of the
7360 -- init-proc tskVIP. What we want is the body discriminal,
7361 -- which is associated to the discriminant of the original
7362 -- concurrent type tsk.
7364 return New_Occurrence_Of
7367 else
7368 Ref :=
7378 -- Start of processing for Actual_Index_Type
7380 begin
7383 then
7386 else
7400 -- Start of processing for Resolve_Entry
7402 begin
7403 -- Find name of entry being called, and resolve prefix of name with its
7404 -- own type. The prefix can be overloaded, and the name and signature of
7405 -- the entry must be taken into account.
7409 -- Case of dealing with entry family within the current tasks
7413 else
7419 -- Entry call to an entry (or entry family) in the current task. This
7420 -- is legal even though the task will deadlock. Rewrite as call to
7421 -- current task.
7423 -- This can also be a call to an entry in an enclosing task. If this
7424 -- is a single task, we have to retrieve its name, because the scope
7425 -- of the entry is the task type, not the object. If the enclosing
7426 -- task is a task type, the identity of the task is given by its own
7427 -- self variable.
7429 -- Finally this can be a requeue on an entry of the same task or
7430 -- protected object.
7437 then
7438 -- S is an enclosing task or protected object. The concurrent
7439 -- declaration has been converted into a type declaration, and
7440 -- the object itself has an object declaration that follows
7441 -- the type in the same declarative part.
7453 -- Call to current task. Will be transformed into call to Self
7460 New_N :=
7463 Selector_Name =>
7470 then
7471 -- Use the entry name (which must be unique at this point) to find
7472 -- the prefix that returns the corresponding task/protected type.
7474 declare
7480 begin
7502 -- Generate a reference for the index when it denotes an entity
7508 -- Up to this point the expression could have been the actual in a
7509 -- simple entry call, and be given by a named association.
7513 else
7519 ------------------------
7520 -- Resolve_Entry_Call --
7521 ------------------------
7532 begin
7533 -- We kill all checks here, because it does not seem worth the effort to
7534 -- do anything better, an entry call is a big operation.
7536 Kill_All_Checks;
7538 -- Processing of the name is similar for entry calls and protected
7539 -- operation calls. Once the entity is determined, we can complete
7540 -- the resolution of the actuals.
7542 -- The selector may be overloaded, in the case of a protected object
7543 -- with overloaded functions. The type of the context is used for
7544 -- resolution.
7549 then
7550 declare
7554 begin
7573 -- Simple entry or protected operation call
7586 -- Call to member of entry family
7593 -- We cannot in general check the maximum depth of protected entry calls
7594 -- at compile time. But we can tell that any protected entry call at all
7595 -- violates a specified nesting depth of zero.
7601 -- Use context type to disambiguate a protected function that can be
7602 -- called without actuals and that returns an array type, and where the
7603 -- argument list may be an indexing of the returned value.
7608 and then
7614 and then
7615 Covers
7618 then
7619 declare
7622 begin
7623 Index_Node :=
7625 Prefix =>
7629 -- Since we are correcting a node classification error made by the
7630 -- parser, we call Replace rather than Rewrite.
7643 then
7644 -- Note the entity being called before rewriting the call, so that
7645 -- it appears used at this point.
7649 -- Rewrite as call to the precondition wrapper, adding the task
7650 -- object to the list of actuals. If the call is to a member of an
7651 -- entry family, include the index as well.
7653 declare
7657 begin
7666 New_Call :=
7668 Name =>
7673 -- Preanalyze and resolve new call. Current procedure is called
7674 -- from Resolve_Call, after which expansion will take place.
7681 -- The operation name may have been overloaded. Order the actuals
7682 -- according to the formals of the resolved entity, and set the return
7683 -- type to that of the operation.
7690 -- Reset the Is_Overloaded flag, since resolution is now completed
7692 -- Simple entry call
7697 -- Call to a member of an entry family
7707 -- Create a call reference to the entry
7715 -- Verify that a procedure call cannot masquerade as an entry
7716 -- call where an entry call is expected.
7721 then
7726 then
7731 then
7736 -- After resolution, entry calls and protected procedure calls are
7737 -- changed into entry calls, for expansion. The structure of the node
7738 -- does not change, so it can safely be done in place. Protected
7739 -- function calls must keep their structure because they are
7740 -- subexpressions.
7744 -- A protected operation that is not a function may modify the
7745 -- corresponding object, and cannot apply to a constant. If this
7746 -- is an internal call, the prefix is the type itself.
7752 then
7753 Error_Msg_N
7755 Entry_Name);
7758 declare
7761 begin
7762 Entry_Call :=
7767 -- Inherit relevant attributes from the original call
7769 Set_First_Named_Actual
7772 Set_Is_Elaboration_Checks_OK_Node
7775 Set_Is_SPARK_Mode_On_Node
7782 -- Protected functions can return on the secondary stack, in which
7783 -- case we must trigger the transient scope mechanism.
7785 elsif Expander_Active
7787 then
7792 -------------------------
7793 -- Resolve_Equality_Op --
7794 -------------------------
7796 -- Both arguments must have the same type, and the boolean context does
7797 -- not participate in the resolution. The first pass verifies that the
7798 -- interpretation is not ambiguous, and the type of the left argument is
7799 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7800 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7801 -- though they carry a single (universal) type. Diagnose this case here.
7809 -- The resolution rule for if expressions requires that each such must
7810 -- have a unique type. This means that if several dependent expressions
7811 -- are of a non-null anonymous access type, and the context does not
7812 -- impose an expected type (as can be the case in an equality operation)
7813 -- the expression must be rejected.
7816 -- Attempt to explain the nature of a redundant comparison with True. If
7817 -- the expression N is too complex, this routine issues a general error
7818 -- message.
7821 -- In the case of allocators and access attributes, the context must
7822 -- provide an indication of the specific access type to be used. If
7823 -- one operand is of such a "generic" access type, check whether there
7824 -- is a specific visible access type that has the same designated type.
7825 -- This is semantically dubious, and of no interest to any real code,
7826 -- but c48008a makes it all worthwhile.
7828 -------------------------
7829 -- Check_If_Expression --
7830 -------------------------
7836 begin
7843 then
7849 ------------------------
7850 -- Explain_Redundancy --
7851 ------------------------
7858 begin
7861 -- Strip the operand down to an entity
7863 loop
7866 else
7871 -- The construct denotes an entity
7876 -- Do not generate an error message when the comparison is done
7877 -- against the enumeration literal Standard.True.
7881 -- Build a customized error message
7908 -- The construct is too complex to disect, issue a general message
7910 else
7915 -----------------------------
7916 -- Find_Unique_Access_Type --
7917 -----------------------------
7924 begin
7926 E_Access_Attribute_Type)
7927 then
7931 E_Access_Attribute_Type)
7932 then
7934 else
7946 then
7959 -- Start of processing for Resolve_Equality_Op
7961 begin
7972 T = Any_Character
7973 then
7976 else
7985 then
7994 -- If expressions must have a single type, and if the context does
7995 -- not impose one the dependent expressions cannot be anonymous
7996 -- access types.
7998 -- Why no similar processing for case expressions???
8002 E_Anonymous_Access_Subprogram_Type)
8004 E_Anonymous_Access_Subprogram_Type)
8005 then
8013 -- In SPARK, equality operators = and /= for array types other than
8014 -- String are only defined when, for each index position, the
8015 -- operands have equal static bounds.
8019 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8020 -- operation if not needed.
8028 then
8029 Check_SPARK_05_Restriction
8034 -- If the unique type is a class-wide type then it will be expanded
8035 -- into a dispatching call to the predefined primitive. Therefore we
8036 -- check here for potential violation of such restriction.
8042 -- Only warn for redundant equality comparison to True for objects
8043 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8044 -- other expressions, it may be a matter of preference to write
8045 -- "Expr = True" or "Expr".
8047 if Warn_On_Redundant_Constructs
8052 and then
8054 or else
8056 then
8057 Error_Msg_N -- CODEFIX
8067 -- If this is an inequality, it may be the implicit inequality
8068 -- created for a user-defined operation, in which case the corres-
8069 -- ponding equality operation is not intrinsic, and the operation
8070 -- cannot be constant-folded. Else fold.
8075 or else Is_Intrinsic_Subprogram
8077 then
8083 then
8087 -- Ada 2005: If one operand is an anonymous access type, convert the
8088 -- other operand to it, to ensure that the underlying types match in
8089 -- the back-end. Same for access_to_subprogram, and the conversion
8090 -- verifies that the types are subtype conformant.
8092 -- We apply the same conversion in the case one of the operands is a
8093 -- private subtype of the type of the other.
8095 -- Why the Expander_Active test here ???
8097 if Expander_Active
8098 and then
8100 E_Anonymous_Access_Subprogram_Type)
8102 then
8122 ----------------------------------
8123 -- Resolve_Explicit_Dereference --
8124 ----------------------------------
8132 -- The candidate prefix type, if overloaded
8137 begin
8141 -- A useful optimization: check whether the dereference denotes an
8142 -- element of a container, and if so rewrite it as a call to the
8143 -- corresponding Element function.
8145 -- Disabled for now, on advice of ARG. A more restricted form of the
8146 -- predicate might be acceptable ???
8148 -- if Is_Container_Element (N) then
8149 -- return;
8150 -- end if;
8154 -- Use the context type to select the prefix that has the correct
8155 -- designated type. Keep the first match, which will be the inner-
8156 -- most.
8163 then
8168 -- Remove access types that do not match, but preserve access
8169 -- to subprogram interpretations, in case a further dereference
8170 -- is needed (see below).
8183 else
8184 -- If no interpretation covers the designated type of the prefix,
8185 -- this is the pathological case where not all implementations of
8186 -- the prefix allow the interpretation of the node as a call. Now
8187 -- that the expected type is known, Remove other interpretations
8188 -- from prefix, rewrite it as a call, and resolve again, so that
8189 -- the proper call node is generated.
8200 New_N :=
8202 Name =>
8213 -- If not overloaded, resolve P with its own type
8215 else
8219 -- If the prefix might be null, add an access check
8223 then
8227 -- If the designated type is a packed unconstrained array type, and the
8228 -- explicit dereference is not in the context of an attribute reference,
8229 -- then we must compute and set the actual subtype, since it is needed
8230 -- by Gigi. The reason we exclude the attribute case is that this is
8231 -- handled fine by Gigi, and in fact we use such attributes to build the
8232 -- actual subtype. We also exclude generated code (which builds actual
8233 -- subtypes directly if they are needed).
8240 then
8246 -- Note: No Eval processing is required for an explicit dereference,
8247 -- because such a name can never be static.
8251 -------------------------------------
8252 -- Resolve_Expression_With_Actions --
8253 -------------------------------------
8256 begin
8259 -- If N has no actions, and its expression has been constant folded,
8260 -- then rewrite N as just its expression. Note, we can't do this in
8261 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8262 -- Expression (N) to be expanded again.
8266 then
8271 ----------------------------------
8272 -- Resolve_Generalized_Indexing --
8273 ----------------------------------
8281 begin
8282 -- In ASIS mode, propagate the information about the indexes back to
8283 -- to the original indexing node. The generalized indexing is either
8284 -- a function call, or a dereference of one. The actuals include the
8285 -- prefix of the original node, which is the container expression.
8294 loop
8303 -- If expression is to be reanalyzed, reset Generalized_Indexing
8304 -- to recreate call node, as is the case when the expression is
8305 -- part of an expression function.
8314 else
8320 ---------------------------
8321 -- Resolve_If_Expression --
8322 ---------------------------
8331 begin
8332 -- Defend against malformed expressions
8350 -- When the "then" expression is of a scalar subtype different from the
8351 -- result subtype, then insert a conversion to ensure the generation of
8352 -- a constraint check. The same is done for the else part below, again
8353 -- comparing subtypes rather than base types.
8360 -- If ELSE expression present, just resolve using the determined type
8361 -- If type is universal, resolve to any member of the class.
8370 else
8380 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8381 -- dynamically tagged must be known statically.
8386 then
8392 -- If no ELSE expression is present, root type must be Standard.Boolean
8393 -- and we provide a Standard.True result converted to the appropriate
8394 -- Boolean type (in case it is a derived boolean type).
8397 Else_Expr :=
8402 else
8416 -------------------------------
8417 -- Resolve_Indexed_Component --
8418 -------------------------------
8426 begin
8434 -- Use the context type to select the prefix that yields the correct
8435 -- component type.
8437 declare
8444 begin
8451 and then
8452 Covers
8455 then
8464 else
8470 else
8481 else
8488 -- If prefix is access type, dereference to get real array type.
8489 -- Note: we do not apply an access check because the expander always
8490 -- introduces an explicit dereference, and the check will happen there.
8496 -- If name was overloaded, set component type correctly now
8497 -- If a misplaced call to an entry family (which has no index types)
8498 -- return. Error will be diagnosed from calling context.
8502 else
8509 -- The prefix may have resolved to a string literal, in which case its
8510 -- etype has a special representation. This is only possible currently
8511 -- if the prefix is a static concatenation, written in functional
8512 -- notation.
8517 else
8524 else
8535 -- Do not generate the warning on suspicious index if we are analyzing
8536 -- package Ada.Tags; otherwise we will report the warning with the
8537 -- Prims_Ptr field of the dispatch table.
8540 or else not
8542 Ada_Tags)
8543 then
8548 -- If the array type is atomic, and the component is not atomic, then
8549 -- this is worth a warning, since we have a situation where the access
8550 -- to the component may cause extra read/writes of the atomic array
8551 -- object, or partial word accesses, which could be unexpected.
8557 and then Has_Atomic_Components
8560 then
8561 Error_Msg_N
8563 Error_Msg_N
8568 -----------------------------
8569 -- Resolve_Integer_Literal --
8570 -----------------------------
8573 begin
8578 --------------------------------
8579 -- Resolve_Intrinsic_Operator --
8580 --------------------------------
8589 -- If the operand is a literal, it cannot be the expression in a
8590 -- conversion. Use a qualified expression instead.
8592 ---------------------
8593 -- Convert_Operand --
8594 ---------------------
8600 begin
8602 Res :=
8608 else
8615 -- Start of processing for Resolve_Intrinsic_Operator
8617 begin
8618 -- We must preserve the original entity in a generic setting, so that
8619 -- the legality of the operation can be verified in an instance.
8634 -- If the result or operand types are private, rewrite with unchecked
8635 -- conversions on the operands and the result, to expose the proper
8636 -- underlying numeric type.
8641 then
8646 else
8667 then
8668 -- Add explicit conversion where needed, and save interpretations in
8669 -- case operands are overloaded.
8676 else
8682 else
8692 else
8697 --------------------------------------
8698 -- Resolve_Intrinsic_Unary_Operator --
8699 --------------------------------------
8701 procedure Resolve_Intrinsic_Unary_Operator
8704 is
8709 begin
8728 else
8733 ------------------------
8734 -- Resolve_Logical_Op --
8735 ------------------------
8740 begin
8743 -- Predefined operations on scalar types yield the base type. On the
8744 -- other hand, logical operations on arrays yield the type of the
8745 -- arguments (and the context).
8749 else
8753 -- The following test is required because the operands of the operation
8754 -- may be literals, in which case the resulting type appears to be
8755 -- compatible with a signed integer type, when in fact it is compatible
8756 -- only with modular types. If the context itself is universal, the
8757 -- operation is illegal.
8765 Error_Msg_N
8773 then
8777 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8778 -- is active and the result type is standard Boolean (do not mess with
8779 -- ops that return a nonstandard Boolean type, because something strange
8780 -- is going on).
8782 -- Note: you might expect this replacement to be done during expansion,
8783 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8784 -- is used, no part of the right operand of an "and" or "or" operator
8785 -- should be executed if the left operand would short-circuit the
8786 -- evaluation of the corresponding "and then" or "or else". If we left
8787 -- the replacement to expansion time, then run-time checks associated
8788 -- with such operands would be evaluated unconditionally, due to being
8789 -- before the condition prior to the rewriting as short-circuit forms
8790 -- during expansion.
8792 if Short_Circuit_And_Or
8795 then
8796 -- Mark the corresponding putative SCO operator as truly a logical
8797 -- (and short-circuit) operator.
8810 -- Case of OR changed to OR ELSE
8812 else
8820 -- Return now, since analysis of the rewritten ops will take care of
8821 -- other reference bookkeeping and expression folding.
8836 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8837 -- only when both operands have same static lower and higher bounds. Of
8838 -- course the types have to match, so only check if operands are
8839 -- compatible and the node itself has no errors.
8843 then
8844 declare
8848 begin
8849 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8850 -- operation if not needed.
8857 then
8858 Check_SPARK_05_Restriction
8865 ---------------------------
8866 -- Resolve_Membership_Op --
8867 ---------------------------
8869 -- The context can only be a boolean type, and does not determine the
8870 -- arguments. Arguments should be unambiguous, but the preference rule for
8871 -- universal types applies.
8881 -- Analysis has determined a unique type for the left operand. Use it to
8882 -- resolve the disjuncts.
8884 ----------------------------
8885 -- Resolve_Set_Membership --
8886 ----------------------------
8892 begin
8893 -- If the left operand is overloaded, find type compatible with not
8894 -- overloaded alternative of the right operand.
8903 else
8908 -- Unclear how to resolve expression if all alternatives are also
8909 -- overloaded.
8915 else
8924 -- Alternative is an expression, a range
8925 -- or a subtype mark.
8929 then
8936 -- Check for duplicates for discrete case
8939 declare
8948 begin
8949 -- Loop checking duplicates. This is quadratic, but giant sets
8950 -- are unlikely in this context so it's a reasonable choice.
8957 N_Character_Literal)
8959 then
8977 -- Start of processing for Resolve_Membership_Op
8979 begin
8985 Resolve_Set_Membership;
8989 and then
8991 or else
8994 then
8997 -- Ada 2005 (AI-251): Support the following case:
8999 -- type I is interface;
9000 -- type T is tagged ...
9002 -- function Test (O : I'Class) is
9003 -- begin
9004 -- return O in T'Class.
9005 -- end Test;
9007 -- In this case we have nothing else to do. The membership test will be
9008 -- done at run time.
9015 then
9017 else
9021 -- If mixed-mode operations are present and operands are all literal,
9022 -- the only interpretation involves Duration, which is probably not
9023 -- the intention of the programmer.
9038 then
9044 else
9049 -- Here after resolving membership operation
9056 ------------------
9057 -- Resolve_Null --
9058 ------------------
9063 begin
9064 -- Handle restriction against anonymous null access values This
9065 -- restriction can be turned off using -gnatdj.
9067 -- Ada 2005 (AI-231): Remove restriction
9070 and then not Debug_Flag_J
9073 then
9074 -- In the common case of a call which uses an explicitly null value
9075 -- for an access parameter, give specialized error message.
9078 Error_Msg_N
9081 -- Standard message for all other cases (are there any?)
9083 else
9084 Error_Msg_N
9089 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9090 -- assignment to a null-excluding object
9095 then
9097 Insert_Action
9102 else
9109 -- In a distributed context, null for a remote access to subprogram may
9110 -- need to be replaced with a special record aggregate. In this case,
9111 -- return after having done the transformation.
9116 then
9120 -- The null literal takes its type from the context
9125 -----------------------
9126 -- Resolve_Op_Concat --
9127 -----------------------
9131 -- We wish to avoid deep recursion, because concatenations are often
9132 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
9133 -- operands nonrecursively until we find something that is not a simple
9134 -- concatenation (A in this case). We resolve that, and then walk back
9135 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
9136 -- to do the rest of the work at each level. The Parent pointers allow
9137 -- us to avoid recursion, and thus avoid running out of memory. See also
9138 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
9143 begin
9144 -- The following code is equivalent to:
9146 -- Resolve_Op_Concat_First (NN, Typ);
9147 -- Resolve_Op_Concat_Arg (N, ...);
9148 -- Resolve_Op_Concat_Rest (N, Typ);
9150 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
9151 -- operand is a concatenation.
9153 -- Walk down left operands
9155 loop
9164 -- Now (given the above example) NN is A&B and Op1 is A
9166 -- First resolve Op1 ...
9170 -- ... then walk NN back up until we reach N (where we started), calling
9171 -- Resolve_Op_Concat_Rest along the way.
9173 loop
9180 Check_SPARK_05_Restriction
9185 ---------------------------
9186 -- Resolve_Op_Concat_Arg --
9187 ---------------------------
9189 procedure Resolve_Op_Concat_Arg
9194 is
9198 begin
9200 if Is_Comp
9204 then
9206 else
9210 -- If both Array & Array and Array & Component are visible, there is a
9211 -- potential ambiguity that must be reported.
9216 then
9220 -- If the operation is user-defined and not overloaded use its
9221 -- profile. The operation may be a renaming, in which case it has
9222 -- been rewritten, and we want the original profile.
9227 then
9229 Etype
9233 -- Otherwise an aggregate may match both the array type and the
9234 -- component type.
9236 else
9241 else
9245 then
9246 declare
9251 begin
9256 -- Special-case the error message when the overloading is
9257 -- caused by a function that yields an array and can be
9258 -- called without parameters.
9263 Error_Msg_NE
9265 Error_Msg_NE
9269 else
9277 or else
9279 then
9280 Error_Msg_N -- CODEFIX
9298 else
9303 else
9307 -- Concatenation is restricted in SPARK: each operand must be either a
9308 -- string literal, the name of a string constant, a static character or
9309 -- string expression, or another concatenation. Arg cannot be a
9310 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9311 -- separately on each final operand, past concatenation operations.
9315 Check_SPARK_05_Restriction
9323 then
9324 Check_SPARK_05_Restriction
9328 -- Do not issue error on an operand that is neither a character nor a
9329 -- string, as the error is issued in Resolve_Op_Concat.
9331 else
9338 -----------------------------
9339 -- Resolve_Op_Concat_First --
9340 -----------------------------
9347 begin
9348 -- The parser folds an enormous sequence of concatenations of string
9349 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9350 -- in the right operand. If the expression resolves to a predefined "&"
9351 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9352 -- we give an error. See P_Simple_Expression in Par.Ch4.
9357 then
9372 ----------------------------
9373 -- Resolve_Op_Concat_Rest --
9374 ----------------------------
9380 begin
9389 -- If this is not a static concatenation, but the result is a string
9390 -- type (and not an array of strings) ensure that static string operands
9391 -- have their subtypes properly constructed.
9395 then
9401 ----------------------
9402 -- Resolve_Op_Expon --
9403 ----------------------
9408 begin
9409 -- Catch attempts to do fixed-point exponentiation with universal
9410 -- operands, which is a case where the illegality is not caught during
9411 -- normal operator analysis. This is not done in preanalysis mode
9412 -- since the tree is not fully decorated during preanalysis.
9424 then
9434 then
9441 then
9445 -- We do the resolution using the base type, because intermediate values
9446 -- in expressions are always of the base type, not a subtype of it.
9451 -- For integer types, right argument must be in Natural range
9466 -- Evaluate the exponentiation operator for dimensioned type
9469 else
9473 -- Set overflow checking bit. Much cleverer code needed here eventually
9474 -- and perhaps the Resolve routines should be separated for the various
9475 -- arithmetic operations, since they will need different processing. ???
9484 --------------------
9485 -- Resolve_Op_Not --
9486 --------------------
9492 -- This function determines if the parent node is a boolean operator or
9493 -- operation (comparison op, membership test, or short circuit form) and
9494 -- the not in question is the left operand of this operation. Note that
9495 -- if the not is in parens, then false is returned.
9497 -----------------------
9498 -- Parent_Is_Boolean --
9499 -----------------------
9502 begin
9506 else
9508 when N_And_Then
9509 | N_In
9510 | N_Not_In
9511 | N_Op_And
9512 | N_Op_Eq
9513 | N_Op_Ge
9514 | N_Op_Gt
9515 | N_Op_Le
9516 | N_Op_Lt
9517 | N_Op_Ne
9518 | N_Op_Or
9519 | N_Op_Xor
9520 | N_Or_Else
9521 =>
9530 -- Start of processing for Resolve_Op_Not
9532 begin
9533 -- Predefined operations on scalar types yield the base type. On the
9534 -- other hand, logical operations on arrays yield the type of the
9535 -- arguments (and the context).
9539 else
9543 -- Straightforward case of incorrect arguments
9550 -- Special case of probable missing parens
9554 Error_Msg_N
9557 else
9558 Error_Msg_N
9565 -- OK resolution of NOT
9567 else
9568 -- Warn if non-boolean types involved. This is a case like not a < b
9569 -- where a and b are modular, where we will get (not a) < b and most
9570 -- likely not (a < b) was intended.
9572 if Warn_On_Questionable_Missing_Parens
9574 and then Parent_Is_Boolean
9575 then
9579 -- Warn on double negation if checking redundant constructs
9581 if Warn_On_Redundant_Constructs
9586 then
9590 -- Complete resolution and evaluation of NOT
9600 -----------------------------
9601 -- Resolve_Operator_Symbol --
9602 -----------------------------
9604 -- Nothing to be done, all resolved already
9610 begin
9614 ----------------------------------
9615 -- Resolve_Qualified_Expression --
9616 ----------------------------------
9624 begin
9627 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9628 -- operation if not needed.
9635 then
9636 Check_SPARK_05_Restriction
9640 -- A qualified expression requires an exact match of the type, class-
9641 -- wide matching is not allowed. However, if the qualifying type is
9642 -- specific and the expression has a class-wide type, it may still be
9643 -- okay, since it can be the result of the expansion of a call to a
9644 -- dispatching function, so we also have to check class-wideness of the
9645 -- type of the expression's original node.
9648 or else
9652 then
9656 -- If the target type is unconstrained, then we reset the type of the
9657 -- result from the type of the expression. For other cases, the actual
9658 -- subtype of the expression is the target type.
9662 then
9669 -- If we still have a qualified expression after the static evaluation,
9670 -- then apply a scalar range check if needed. The reason that we do this
9671 -- after the Eval call is that otherwise, the application of the range
9672 -- check may convert an illegal static expression and result in warning
9673 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9679 -- Finally, check whether a predicate applies to the target type. This
9680 -- comes from AI12-0100. As for type conversions, check the enclosing
9681 -- context to prevent an infinite expansion.
9687 or else
9689 then
9692 -- In the case of a qualified expression in an allocator, the check
9693 -- is applied when expanding the allocator, so avoid redundant check.
9697 then
9703 ------------------------------
9704 -- Resolve_Raise_Expression --
9705 ------------------------------
9708 begin
9712 else
9717 -------------------
9718 -- Resolve_Range --
9719 -------------------
9726 -- Returns True if N is of the form X'First .. X'Last where X is the
9727 -- same entity for both attributes.
9729 --------------------
9730 -- First_Last_Ref --
9731 --------------------
9737 begin
9742 then
9743 declare
9746 begin
9750 then
9759 -- Start of processing for Resolve_Range
9761 begin
9764 -- The lower bound should be in Typ. The higher bound can be in Typ's
9765 -- base type if the range is null. It may still be invalid if it is
9766 -- higher than the lower bound. This is checked later in the context in
9767 -- which the range appears.
9772 -- Check for inappropriate range on unordered enumeration type
9776 -- Exclude X'First .. X'Last if X is the same entity for both
9778 and then not First_Last_Ref
9779 then
9781 Error_Msg_NE
9788 -- We have to check the bounds for being within the base range as
9789 -- required for a non-static context. Normally this is automatic and
9790 -- done as part of evaluating expressions, but the N_Range node is an
9791 -- exception, since in GNAT we consider this node to be a subexpression,
9792 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9793 -- this, but that would put the test on the main evaluation path for
9794 -- expressions.
9799 -- Check for an ambiguous range over character literals. This will
9800 -- happen with a membership test involving only literals.
9808 -- If bounds are static, constant-fold them, so size computations are
9809 -- identical between front-end and back-end. Do not perform this
9810 -- transformation while analyzing generic units, as type information
9811 -- would be lost when reanalyzing the constant node in the instance.
9824 --------------------------
9825 -- Resolve_Real_Literal --
9826 --------------------------
9831 begin
9832 -- Special processing for fixed-point literals to make sure that the
9833 -- value is an exact multiple of small where this is required. We skip
9834 -- this for the universal real case, and also for generic types.
9840 then
9841 declare
9848 begin
9849 -- Case of literal is not an exact multiple of the Small
9853 -- For a source program literal for a decimal fixed-point type,
9854 -- this is statically illegal (RM 4.9(36)).
9859 then
9863 -- Generate a warning if literal from source
9866 and then Warn_On_Bad_Fixed_Value
9867 then
9868 Error_Msg_N
9870 N);
9873 -- Replace literal by a value that is the exact representation
9874 -- of a value of the type, i.e. a multiple of the small value,
9875 -- by truncation, since Machine_Rounds is false for all GNAT
9876 -- fixed-point types (RM 4.9(38)).
9886 -- In all cases, set the corresponding integer field
9892 -- Now replace the actual type by the expected type as usual
9898 -----------------------
9899 -- Resolve_Reference --
9900 -----------------------
9905 begin
9906 -- Replace general access with specific type
9914 -- If we are taking the reference of a volatile entity, then treat it as
9915 -- a potential modification of this entity. This is too conservative,
9916 -- but necessary because remove side effects can cause transformations
9917 -- of normal assignments into reference sequences that otherwise fail to
9918 -- notice the modification.
9925 --------------------------------
9926 -- Resolve_Selected_Component --
9927 --------------------------------
9942 -- Check whether this is the initialization of a component within an
9943 -- init proc (by assignment or call to another init proc). If true,
9944 -- there is no need for a discriminant check.
9946 --------------------
9947 -- Init_Component --
9948 --------------------
9951 begin
9952 return Inside_Init_Proc
9958 -- Start of processing for Resolve_Selected_Component
9960 begin
9963 -- Use the context type to select the prefix that has a selector
9964 -- of the correct name and type.
9972 else
9976 -- Locate selected component. For a private prefix the selector
9977 -- can denote a discriminant.
9981 -- The visible components of a class-wide type are those of
9982 -- the root type.
9992 then
9999 else
10003 Error_Msg_N
10008 else
10011 -- There may be an implicit dereference. Retrieve
10012 -- designated record type.
10016 else
10022 -- Resolution chooses the new interpretation.
10023 -- Find the component with the right name.
10028 loop
10045 -- There must be a legal interpretation at this point
10052 else
10053 -- Resolve prefix with its type
10058 -- Generate cross-reference. We needed to wait until full overloading
10059 -- resolution was complete to do this, since otherwise we can't tell if
10060 -- we are an lvalue or not.
10064 else
10068 -- If prefix is an access type, the node will be transformed into an
10069 -- explicit dereference during expansion. The type of the node is the
10070 -- designated type of that of the prefix.
10075 else
10079 -- Set flag for expander if discriminant check required on a component
10080 -- appearing within a variant.
10086 and then
10089 and then not Init_Component
10090 then
10098 -- If the prefix is a record conversion, this may be a renamed
10099 -- discriminant whose bounds differ from those of the original
10100 -- one, so we must ensure that a range check is performed.
10105 then
10109 -- Note: No Eval processing is required, because the prefix is of a
10110 -- record type, or protected type, and neither can possibly be static.
10112 -- If the record type is atomic, and the component is non-atomic, then
10113 -- this is worth a warning, since we have a situation where the access
10114 -- to the component may cause extra read/writes of the atomic array
10115 -- object, or partial word accesses, both of which may be unexpected.
10121 then
10122 Error_Msg_N
10125 Error_Msg_N
10133 -------------------
10134 -- Resolve_Shift --
10135 -------------------
10142 begin
10143 -- We do the resolution using the base type, because intermediate values
10144 -- in expressions always are of the base type, not a subtype of it.
10157 ---------------------------
10158 -- Resolve_Short_Circuit --
10159 ---------------------------
10166 begin
10167 -- Ensure all actions associated with the left operand (e.g.
10168 -- finalization of transient objects) are fully evaluated locally within
10169 -- an expression with actions. This is particularly helpful for coverage
10170 -- analysis. However this should not happen in generics or if option
10171 -- Minimize_Expression_With_Actions is set.
10174 declare
10176 begin
10184 -- Set Comes_From_Source on L to preserve warnings for unset
10185 -- reference.
10194 -- Check for issuing warning for always False assert/check, this happens
10195 -- when assertions are turned off, in which case the pragma Assert/Check
10196 -- was transformed into:
10198 -- if False and then <condition> then ...
10200 -- and we detect this pattern
10202 if Warn_On_Assertion_Failure
10209 then
10210 declare
10213 begin
10214 -- Special handling of Asssert pragma
10218 then
10219 declare
10221 Original_Node
10222 (Expression
10225 begin
10226 -- Don't warn if original condition is explicit False,
10227 -- since obviously the failure is expected in this case.
10231 then
10234 -- Issue warning. We do not want the deletion of the
10235 -- IF/AND-THEN to take this message with it. We achieve this
10236 -- by making sure that the expanded code points to the Sloc
10237 -- of the expression, not the original pragma.
10239 else
10240 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10241 -- The source location of the expression is not usually
10242 -- the best choice here. For example, it gets located on
10243 -- the last AND keyword in a chain of boolean expressiond
10244 -- AND'ed together. It is best to put the message on the
10245 -- first character of the assertion, which is the effect
10246 -- of the First_Node call here.
10248 Error_Msg_F
10250 Expression
10255 -- Similar processing for Check pragma
10259 then
10260 -- Don't want to warn if original condition is explicit False
10262 declare
10264 Original_Node
10265 (Expression
10267 begin
10270 then
10273 -- Post warning
10275 else
10276 -- Again use Error_Msg_F rather than Error_Msg_N, see
10277 -- comment above for an explanation of why we do this.
10279 Error_Msg_F
10281 Expression
10289 -- Continue with processing of short circuit
10298 -------------------
10299 -- Resolve_Slice --
10300 -------------------
10309 begin
10312 -- Use the context type to select the prefix that yields the correct
10313 -- array type.
10315 declare
10322 begin
10330 then
10338 else
10343 else
10354 else
10364 -- If the prefix is an access to an unconstrained array, we must use
10365 -- the actual subtype of the object to perform the index checks. The
10366 -- object denoted by the prefix is implicit in the node, so we build
10367 -- an explicit representation for it in order to compute the actual
10368 -- subtype.
10373 declare
10377 begin
10388 then
10391 -- If the name is a selected component that depends on discriminants,
10392 -- build an actual subtype for it. This can happen only when the name
10393 -- itself is overloaded; otherwise the actual subtype is created when
10394 -- the selected component is analyzed.
10397 and then Full_Analysis
10399 then
10400 declare
10403 begin
10408 -- Maybe this should just be "else", instead of checking for the
10409 -- specific case of slice??? This is needed for the case where the
10410 -- prefix is an Image attribute, which gets expanded to a slice, and so
10411 -- has a constrained subtype which we want to use for the slice range
10412 -- check applied below (the range check won't get done if the
10413 -- unconstrained subtype of the 'Image is used).
10419 -- Obtain the type of the array index
10423 else
10427 -- If name was overloaded, set slice type correctly now
10431 -- Handle the generation of a range check that compares the array index
10432 -- against the discrete_range. The check is not applied to internally
10433 -- built nodes associated with the expansion of dispatch tables. Check
10434 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10435 -- the unit.
10437 if Tagged_Type_Expansion
10443 then
10446 -- The discrete_range is specified by a subtype indication. Create a
10447 -- shallow copy and inherit the type, parent and source location from
10448 -- the discrete_range. This ensures that the range check is inserted
10449 -- relative to the slice and that the runtime exception points to the
10450 -- proper construct.
10459 -- The discrete_range is a regular range. Resolve the bounds and remove
10460 -- their side effects.
10462 else
10479 -- Check bad use of type with predicates
10481 declare
10484 begin
10487 then
10489 else
10494 Bad_Predicated_Subtype_Use
10499 -- Otherwise here is where we check suspicious indexes
10510 ----------------------------
10511 -- Resolve_String_Literal --
10512 ----------------------------
10523 begin
10524 -- For a string appearing in a concatenation, defer creation of the
10525 -- string_literal_subtype until the end of the resolution of the
10526 -- concatenation, because the literal may be constant-folded away. This
10527 -- is a useful optimization for long concatenation expressions.
10529 -- If the string is an aggregate built for a single character (which
10530 -- happens in a non-static context) or a is null string to which special
10531 -- checks may apply, we build the subtype. Wide strings must also get a
10532 -- string subtype if they come from a one character aggregate. Strings
10533 -- generated by attributes might be static, but it is often hard to
10534 -- determine whether the enclosing context is static, so we generate
10535 -- subtypes for them as well, thus losing some rarer optimizations ???
10536 -- Same for strings that come from a static conversion.
10538 Need_Check :=
10547 -- If the resolving type is itself a string literal subtype, we can just
10548 -- reuse it, since there is no point in creating another.
10554 and then not Need_Check
10556 N_Attribute_Reference,
10557 N_Qualified_Expression,
10558 N_Type_Conversion)
10559 then
10562 -- Do not generate a string literal subtype for the default expression
10563 -- of a formal parameter in GNATprove mode. This is because the string
10564 -- subtype is associated with the freezing actions of the subprogram,
10565 -- however freezing is disabled in GNATprove mode and as a result the
10566 -- subtype is unavailable.
10568 elsif GNATprove_Mode
10570 then
10573 -- Otherwise we must create a string literal subtype. Note that the
10574 -- whole idea of string literal subtypes is simply to avoid the need
10575 -- for building a full fledged array subtype for each literal.
10577 else
10583 or else Need_Check
10584 then
10591 then
10597 -- The validity of a null string has been checked in the call to
10598 -- Eval_String_Literal.
10603 -- Always accept string literal with component type Any_Character, which
10604 -- occurs in error situations and in comparisons of literals, both of
10605 -- which should accept all literals.
10610 -- If the type is bit-packed, then we always transform the string
10611 -- literal into a full fledged aggregate.
10616 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10618 else
10619 -- For Standard.Wide_Wide_String, or any other type whose component
10620 -- type is Standard.Wide_Wide_Character, we know that all the
10621 -- characters in the string must be acceptable, since the parser
10622 -- accepted the characters as valid character literals.
10627 -- For the case of Standard.String, or any other type whose component
10628 -- type is Standard.Character, we must make sure that there are no
10629 -- wide characters in the string, i.e. that it is entirely composed
10630 -- of characters in range of type Character.
10632 -- If the string literal is the result of a static concatenation, the
10633 -- test has already been performed on the components, and need not be
10634 -- repeated.
10638 then
10642 -- If we are out of range, post error. This is one of the
10643 -- very few places that we place the flag in the middle of
10644 -- a token, right under the offending wide character. Not
10645 -- quite clear if this is right wrt wide character encoding
10646 -- sequences, but it's only an error message.
10648 Error_Msg
10655 -- For the case of Standard.Wide_String, or any other type whose
10656 -- component type is Standard.Wide_Character, we must make sure that
10657 -- there are no wide characters in the string, i.e. that it is
10658 -- entirely composed of characters in range of type Wide_Character.
10660 -- If the string literal is the result of a static concatenation,
10661 -- the test has already been performed on the components, and need
10662 -- not be repeated.
10666 then
10670 -- If we are out of range, post error. This is one of the
10671 -- very few places that we place the flag in the middle of
10672 -- a token, right under the offending wide character.
10674 -- This is not quite right, because characters in general
10675 -- will take more than one character position ???
10677 Error_Msg
10684 -- If the root type is not a standard character, then we will convert
10685 -- the string into an aggregate and will let the aggregate code do
10686 -- the checking. Standard Wide_Wide_Character is also OK here.
10688 else
10692 -- See if the component type of the array corresponding to the string
10693 -- has compile time known bounds. If yes we can directly check
10694 -- whether the evaluation of the string will raise constraint error.
10695 -- Otherwise we need to transform the string literal into the
10696 -- corresponding character aggregate and let the aggregate code do
10697 -- the checking.
10701 -- Check for the case of full range, where we are definitely OK
10707 -- Here the range is not the complete base type range, so check
10709 declare
10717 begin
10720 then
10726 then
10727 Apply_Compile_Time_Constraint_Error
10729 CE_Range_Check_Failed,
10740 -- If we got here we meed to transform the string literal into the
10741 -- equivalent qualified positional array aggregate. This is rather
10742 -- heavy artillery for this situation, but it is hard work to avoid.
10744 declare
10749 begin
10750 -- Build the character literals, we give them source locations that
10751 -- correspond to the string positions, which is a bit tricky given
10752 -- the possible presence of wide character escape sequences.
10766 -- Should we have a call to Skip_Wide here ???
10768 -- ??? else
10769 -- Skip_Wide (P);
10777 Expression =>
10784 -------------------------
10785 -- Resolve_Target_Name --
10786 -------------------------
10789 begin
10793 -----------------------------
10794 -- Resolve_Type_Conversion --
10795 -----------------------------
10807 -- Set to False to suppress cases where we want to suppress the test
10808 -- for redundancy to avoid possible false positives on this warning.
10810 begin
10811 if not Conv_OK
10813 then
10817 -- If the Operand Etype is Universal_Fixed, then the conversion is
10818 -- never redundant. We need this check because by the time we have
10819 -- finished the rather complex transformation, the conversion looks
10820 -- redundant when it is not.
10825 -- If the operand is marked as Any_Fixed, then special processing is
10826 -- required. This is also a case where we suppress the test for a
10827 -- redundant conversion, since most certainly it is not redundant.
10832 -- Mixed-mode operation involving a literal. Context must be a fixed
10833 -- type which is applied to the literal subsequently.
10835 -- Multiplication and division involving two fixed type operands must
10836 -- yield a universal real because the result is computed in arbitrary
10837 -- precision.
10843 then
10849 or else
10851 then
10852 -- Return if expression is ambiguous
10857 -- If nothing else, the available fixed type is Duration
10859 else
10863 -- Resolve the real operand with largest available precision
10867 else
10873 -- If the operand is a literal (it could be a non-static and
10874 -- illegal exponentiation) check whether the use of Duration
10875 -- is potentially inaccurate.
10880 then
10881 Error_Msg_N
10884 Error_Msg_N
10891 then
10894 else
10903 -- In SPARK, a type conversion between array types should be restricted
10904 -- to types which have matching static bounds.
10906 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10907 -- operation if not needed.
10914 then
10915 Check_SPARK_05_Restriction
10919 -- In formal mode, the operand of an ancestor type conversion must be an
10920 -- object (not an expression).
10928 then
10934 -- Note: we do the Eval_Type_Conversion call before applying the
10935 -- required checks for a subtype conversion. This is important, since
10936 -- both are prepared under certain circumstances to change the type
10937 -- conversion to a constraint error node, but in the case of
10938 -- Eval_Type_Conversion this may reflect an illegality in the static
10939 -- case, and we would miss the illegality (getting only a warning
10940 -- message), if we applied the type conversion checks first.
10944 -- Even when evaluation is not possible, we may be able to simplify the
10945 -- conversion or its expression. This needs to be done before applying
10946 -- checks, since otherwise the checks may use the original expression
10947 -- and defeat the simplifications. This is specifically the case for
10948 -- elimination of the floating-point Truncation attribute in
10949 -- float-to-int conversions.
10953 -- If after evaluation we still have a type conversion, then we may need
10954 -- to apply checks required for a subtype conversion.
10956 -- Skip these type conversion checks if universal fixed operands
10957 -- operands involved, since range checks are handled separately for
10958 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10964 then
10968 -- Issue warning for conversion of simple object to its own type. We
10969 -- have to test the original nodes, since they may have been rewritten
10970 -- by various optimizations.
10974 -- Here we test for a redundant conversion if the warning mode is
10975 -- active (and was not locally reset), and we have a type conversion
10976 -- from source not appearing in a generic instance.
10978 if Test_Redundant
10981 and then not In_Instance
10982 then
10986 -- If the node is part of a larger expression, the Target_Type
10987 -- may not be the original type of the node if the context is a
10988 -- condition. Recover original type to see if conversion is needed.
10992 then
10996 -- If we have an entity name, then give the warning if the entity
10997 -- is the right type, or if it is a loop parameter covered by the
10998 -- original type (that's needed because loop parameters have an
10999 -- odd subtype coming from the bounds).
11002 and then
11004 or else
11008 -- If not an entity, then type of expression must match
11011 then
11012 -- One more check, do not give warning if the analyzed conversion
11013 -- has an expression with non-static bounds, and the bounds of the
11014 -- target are static. This avoids junk warnings in cases where the
11015 -- conversion is necessary to establish staticness, for example in
11016 -- a case statement.
11020 then
11023 -- Finally, if this type conversion occurs in a context requiring
11024 -- a prefix, and the expression is a qualified expression then the
11025 -- type conversion is not redundant, since a qualified expression
11026 -- is not a prefix, whereas a type conversion is. For example, "X
11027 -- := T'(Funx(...)).Y;" is illegal because a selected component
11028 -- requires a prefix, but a type conversion makes it legal: "X :=
11029 -- T(T'(Funx(...))).Y;"
11031 -- In Ada 2012, a qualified expression is a name, so this idiom is
11032 -- no longer needed, but we still suppress the warning because it
11033 -- seems unfriendly for warnings to pop up when you switch to the
11034 -- newer language version.
11038 N_Indexed_Component,
11039 N_Selected_Component,
11040 N_Slice,
11041 N_Explicit_Dereference)
11042 then
11045 -- Never warn on conversion to Long_Long_Integer'Base since
11046 -- that is most likely an artifact of the extended overflow
11047 -- checking and comes from complex expanded code.
11052 -- Here we give the redundant conversion warning. If it is an
11053 -- entity, give the name of the entity in the message. If not,
11054 -- just mention the expression.
11056 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
11058 else
11061 Error_Msg_NE -- CODEFIX
11064 else
11065 Error_Msg_NE
11073 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
11074 -- No need to perform any interface conversion if the type of the
11075 -- expression coincides with the target type.
11078 and then Expander_Active
11080 then
11081 declare
11085 begin
11086 -- If the type of the operand is a limited view, use nonlimited
11087 -- view when available. If it is a class-wide type, recover the
11088 -- class-wide type of the nonlimited view.
11092 then
11108 -- Conversion from interface type
11112 -- Ada 2005 (AI-217): Handle entities from limited views
11116 Error_Msg_NE -- CODEFIX
11119 Error_Msg_N
11121 N);
11124 and then not
11127 then
11129 Error_Msg_NE -- CODEFIX
11132 Error_Msg_N
11134 N);
11136 else
11140 -- Conversion to interface type
11144 -- Handle subtypes
11151 or else Interface_Present_In_Ancestor
11154 then
11156 else
11159 Error_Msg_N
11167 -- Ada 2012: once the type conversion is resolved, check whether the
11168 -- operand statisfies the static predicate of the target type.
11174 -- If at this stage we have a real to integer conversion, make sure that
11175 -- the Do_Range_Check flag is set, because such conversions in general
11176 -- need a range check. We only need this if expansion is off.
11177 -- In GNATprove mode, we only do that when converting from fixed-point
11178 -- (as floating-point to integer conversions are now handled in
11179 -- GNATprove mode).
11182 and then not Expander_Active
11187 then
11191 -- Generating C code a type conversion of an access to constrained
11192 -- array type to access to unconstrained array type involves building
11193 -- a fat pointer which in general cannot be generated on the fly. We
11194 -- remove side effects in order to store the result of the conversion
11195 -- into a temporary.
11197 if Modify_Tree_For_C
11204 then
11209 ----------------------
11210 -- Resolve_Unary_Op --
11211 ----------------------
11220 begin
11223 Check_SPARK_05_Restriction
11227 -- Deal with intrinsic unary operators
11233 then
11238 -- Deal with universal cases
11241 or else
11243 then
11250 -- Generate warning for expressions like abs (x mod 2)
11252 if Warn_On_Redundant_Constructs
11254 then
11258 Error_Msg_N -- CODEFIX
11263 -- Deal with reference generation
11270 -- Set overflow checking bit. Much cleverer code needed here eventually
11271 -- and perhaps the Resolve routines should be separated for the various
11272 -- arithmetic operations, since they will need different processing ???
11280 -- Generate warning for expressions like -5 mod 3 for integers. No need
11281 -- to worry in the floating-point case, since parens do not affect the
11282 -- result so there is no point in giving in a warning.
11284 declare
11293 begin
11294 if Warn_On_Questionable_Missing_Parens
11298 then
11301 -- We are looking for cases where the right operand is not
11302 -- parenthesized, and is a binary operator, multiply, divide, or
11303 -- mod. These are the cases where the grouping can affect results.
11307 then
11308 -- For mod, we always give the warning, since the value is
11309 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11310 -- -(5 mod 315)). But for the other cases, the only concern is
11311 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11312 -- overflows, but (-2) * 64 does not). So we try to give the
11313 -- message only when overflow is possible.
11317 then
11322 else
11328 else
11332 -- Note that the test below is deliberately excluding the
11333 -- largest negative number, since that is a potentially
11334 -- troublesome case (e.g. -2 * x, where the result is the
11335 -- largest negative integer has an overflow with 2 * x).
11342 -- For the multiplication case, the only case we have to worry
11343 -- about is when (-a)*b is exactly the largest negative number
11344 -- so that -(a*b) can cause overflow. This can only happen if
11345 -- a is a power of 2, and more generally if any operand is a
11346 -- constant that is not a power of 2, then the parentheses
11347 -- cannot affect whether overflow occurs. We only bother to
11348 -- test the left most operand
11350 -- Loop looking at left operands for one that has known value
11357 -- Operand value of 0 or 1 skips warning
11362 -- Otherwise check power of 2, if power of 2, warn, if
11363 -- anything else, skip warning.
11365 else
11369 else
11378 -- Keep looking at left operands
11383 -- For rem or "/" we can only have a problematic situation
11384 -- if the divisor has a value of minus one or one. Otherwise
11385 -- overflow is impossible (divisor > 1) or we have a case of
11386 -- division by zero in any case.
11391 then
11395 -- If we fall through warning should be issued
11397 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11399 Error_Msg_N
11406 ----------------------------------
11407 -- Resolve_Unchecked_Expression --
11408 ----------------------------------
11410 procedure Resolve_Unchecked_Expression
11413 is
11414 begin
11419 ---------------------------------------
11420 -- Resolve_Unchecked_Type_Conversion --
11421 ---------------------------------------
11423 procedure Resolve_Unchecked_Type_Conversion
11426 is
11432 begin
11433 -- Resolve operand using its own type
11437 -- In an inlined context, the unchecked conversion may be applied
11438 -- to a literal, in which case its type is the type of the context.
11439 -- (In other contexts conversions cannot apply to literals).
11441 if In_Inlined_Body
11445 then
11453 ------------------------------
11454 -- Rewrite_Operator_As_Call --
11455 ------------------------------
11462 begin
11469 New_N :=
11480 ------------------------------
11481 -- Rewrite_Renamed_Operator --
11482 ------------------------------
11484 procedure Rewrite_Renamed_Operator
11488 is
11493 begin
11494 -- Do not perform this transformation within a pre/postcondition,
11495 -- because the expression will be reanalyzed, and the transformation
11496 -- might affect the visibility of the operator, e.g. in an instance.
11497 -- Note that fully analyzed and expanded pre/postconditions appear as
11498 -- pragma Check equivalents.
11504 -- Likewise when an expression function is being preanalyzed, since the
11505 -- expression will be reanalyzed as part of the generated body.
11508 declare
11510 begin
11513 N_Expression_Function
11514 then
11520 -- Rewrite the operator node using the real operator, not its renaming.
11521 -- Exclude user-defined intrinsic operations of the same name, which are
11522 -- treated separately and rewritten as calls.
11531 -- Indicate that both the original entity and its renaming are
11532 -- referenced at this point.
11543 -- If the context type is private, add the appropriate conversions so
11544 -- that the operator is applied to the full view. This is done in the
11545 -- routines that resolve intrinsic operators.
11549 when N_Op_Add
11550 | N_Op_Divide
11551 | N_Op_Expon
11552 | N_Op_Mod
11553 | N_Op_Multiply
11554 | N_Op_Rem
11555 | N_Op_Subtract
11556 =>
11559 when N_Op_Abs
11560 | N_Op_Minus
11561 | N_Op_Plus
11562 =>
11572 -- Operator renames a user-defined operator of the same name. Use the
11573 -- original operator in the node, which is the one Gigi knows about.
11580 -----------------------
11581 -- Set_Slice_Subtype --
11582 -----------------------
11584 -- Build an implicit subtype declaration to represent the type delivered by
11585 -- the slice. This is an abbreviated version of an array subtype. We define
11586 -- an index subtype for the slice, using either the subtype name or the
11587 -- discrete range of the slice. To be consistent with index usage elsewhere
11588 -- we create a list header to hold the single index. This list is not
11589 -- otherwise attached to the syntax tree.
11600 begin
11606 else
11607 -- We force the evaluation of a range. This is definitely needed in
11608 -- the renamed case, and seems safer to do unconditionally. Note in
11609 -- any case that since we will create and insert an Itype referring
11610 -- to this range, we must make sure any side effect removal actions
11611 -- are inserted before the Itype definition.
11617 -- If the discrete range is given by a subtype indication, the
11618 -- type of the slice is the base of the subtype mark.
11621 declare
11623 begin
11632 -- Take a new copy of Drange (where bounds have been rewritten to
11633 -- reference side-effect-free names). Using a separate tree ensures
11634 -- that further expansion (e.g. while rewriting a slice assignment
11635 -- into a FOR loop) does not attempt to remove side effects on the
11636 -- bounds again (which would cause the bounds in the index subtype
11637 -- definition to refer to temporaries before they are defined) (the
11638 -- reason is that some names are considered side effect free here
11639 -- for the subtype, but not in the context of a loop iteration
11640 -- scheme).
11661 -- The Etype of the existing Slice node is reset to this slice subtype.
11662 -- Its bounds are obtained from its first index.
11666 -- For bit-packed slice subtypes, freeze immediately (except in the case
11667 -- of being in a "spec expression" where we never freeze when we first
11668 -- see the expression).
11673 -- For all other cases insert an itype reference in the slice's actions
11674 -- so that the itype is frozen at the proper place in the tree (i.e. at
11675 -- the point where actions for the slice are analyzed). Note that this
11676 -- is different from freezing the itype immediately, which might be
11677 -- premature (e.g. if the slice is within a transient scope). This needs
11678 -- to be done only if expansion is enabled.
11685 --------------------------------
11686 -- Set_String_Literal_Subtype --
11687 --------------------------------
11695 begin
11707 -- The low bound is set from the low bound of the corresponding index
11708 -- type. Note that we do not store the high bound in the string literal
11709 -- subtype, but it can be deduced if necessary from the length and the
11710 -- low bound.
11715 -- If the lower bound is not static we create a range for the string
11716 -- literal, using the index type and the known length of the literal.
11717 -- The index type is not necessarily Positive, so the upper bound is
11718 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11720 else
11721 declare
11727 Prefix =>
11731 Left_Opnd =>
11734 Prefix =>
11736 Expressions =>
11738 Right_Opnd =>
11747 begin
11749 Set_String_Literal_Low_Bound
11752 else
11753 -- If the index type is an enumeration type, build bounds
11754 -- expression with attributes.
11756 Set_String_Literal_Low_Bound
11760 Prefix =>
11767 -- Build bona fide subtype for the string, and wrap it in an
11768 -- unchecked conversion, because the backend expects the
11769 -- String_Literal_Subtype to have a static lower bound.
11771 Index_Subtype :=
11778 -- In the context, the Index_Type may already have a constraint,
11779 -- so use common base type on string subtype. The base type may
11780 -- be used when generating attributes of the string, for example
11781 -- in the context of a slice assignment.
11806 ------------------------------
11807 -- Simplify_Type_Conversion --
11808 ------------------------------
11811 begin
11813 declare
11818 begin
11819 -- Special processing if the conversion is the expression of a
11820 -- Rounding or Truncation attribute reference. In this case we
11821 -- replace:
11823 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11825 -- by
11827 -- ityp (x)
11829 -- with the Float_Truncate flag set to False or True respectively,
11830 -- which is more efficient.
11833 and then
11839 Name_Truncation)
11840 then
11841 declare
11844 begin
11854 -----------------------------
11855 -- Unique_Fixed_Point_Type --
11856 -----------------------------
11860 -- Give error messages for true ambiguity. Messages are posted on node
11861 -- N, and entities T1, T2 are the possible interpretations.
11863 -----------------------
11864 -- Fixed_Point_Error --
11865 -----------------------
11868 begin
11874 -- Local variables
11882 -- Start of processing for Unique_Fixed_Point_Type
11884 begin
11885 -- The operations on Duration are visible, so Duration is always a
11886 -- possible interpretation.
11890 -- Look for fixed-point types in enclosing scopes
11899 then
11903 else
11914 -- Look for visible fixed type declarations in the context
11925 then
11929 else
11944 else
11945 -- When the context is a type conversion, issue the warning on the
11946 -- expression of the conversion because it is the actual operation.
11950 else
11954 Error_Msg_NE
11961 ----------------------
11962 -- Valid_Conversion --
11963 ----------------------
11965 function Valid_Conversion
11970 is
11975 function Conversion_Check
11978 -- Little routine to post Msg if Valid is False, returns Valid value
11981 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11983 procedure Conversion_Error_NE
11987 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11990 -- Return True if expression is within an instance but is not in one of
11991 -- the actuals of the instantiation. Type conversions within an instance
11992 -- are not rechecked because type visbility may lead to spurious errors,
11993 -- but conversions in an actual for a formal object must be checked.
11995 function Valid_Tagged_Conversion
11998 -- Specifically test for validity of tagged conversions
12001 -- Check index and component conformance, and accessibility levels if
12002 -- the component types are anonymous access types (Ada 2005).
12004 ----------------------
12005 -- Conversion_Check --
12006 ----------------------
12008 function Conversion_Check
12011 is
12012 begin
12013 if not Valid
12015 -- A generic unit has already been analyzed and we have verified
12016 -- that a particular conversion is OK in that context. Since the
12017 -- instance is reanalyzed without relying on the relationships
12018 -- established during the analysis of the generic, it is possible
12019 -- to end up with inconsistent views of private types. Do not emit
12020 -- the error message in such cases. The rest of the machinery in
12021 -- Valid_Conversion still ensures the proper compatibility of
12022 -- target and operand types.
12024 and then not In_Instance_Code
12025 then
12032 ------------------------
12033 -- Conversion_Error_N --
12034 ------------------------
12037 begin
12043 -------------------------
12044 -- Conversion_Error_NE --
12045 -------------------------
12047 procedure Conversion_Error_NE
12051 is
12052 begin
12058 ----------------------
12059 -- In_Instance_Code --
12060 ----------------------
12065 begin
12069 else
12073 -- The expression is part of an actual object if it appears in
12074 -- the generated object declaration in the instance.
12078 then
12081 else
12082 exit when
12091 -- Otherwise the expression appears within the instantiated unit
12097 ----------------------------
12098 -- Valid_Array_Conversion --
12099 ----------------------------
12116 begin
12117 -- Error if wrong number of dimensions
12119 if
12121 then
12122 Conversion_Error_N
12126 -- Number of dimensions matches
12128 else
12129 -- Loop through indexes of the two arrays
12137 -- Error if index types are incompatible
12143 then
12144 Conversion_Error_N
12146 Operand);
12154 -- If component types have same base type, all set
12159 -- Here if base types of components are not the same. The only
12160 -- time this is allowed is if we have anonymous access types.
12162 -- The conversion of arrays of anonymous access types can lead
12163 -- to dangling pointers. AI-392 formalizes the accessibility
12164 -- checks that must be applied to such conversions to prevent
12165 -- out-of-scope references.
12167 elsif Ekind_In
12169 E_Anonymous_Access_Subprogram_Type)
12171 and then
12173 then
12176 then
12179 Conversion_Error_N
12189 -- Conversion not allowed because of accessibility levels
12191 else
12192 Conversion_Error_N
12198 else
12202 -- All other cases where component base types do not match
12204 else
12205 Conversion_Error_N
12207 Operand);
12211 -- Check that component subtypes statically match. For numeric
12212 -- types this means that both must be either constrained or
12213 -- unconstrained. For enumeration types the bounds must match.
12214 -- All of this is checked in Subtypes_Statically_Match.
12216 if not Subtypes_Statically_Match
12218 then
12219 Conversion_Error_N
12228 -----------------------------
12229 -- Valid_Tagged_Conversion --
12230 -----------------------------
12232 function Valid_Tagged_Conversion
12235 is
12236 begin
12237 -- Upward conversions are allowed (RM 4.6(22))
12241 then
12244 -- Downward conversion are allowed if the operand is class-wide
12245 -- (RM 4.6(23)).
12249 then
12254 then
12255 return
12259 -- Ada 2005 (AI-251): The conversion to/from interface types is
12260 -- always valid. The types involved may be class-wide (sub)types.
12264 then
12267 -- If the operand is a class-wide type obtained through a limited_
12268 -- with clause, and the context includes the nonlimited view, use
12269 -- it to determine whether the conversion is legal.
12275 then
12280 then
12283 else
12284 Conversion_Error_NE
12291 -- Start of processing for Valid_Conversion
12293 begin
12297 declare
12305 begin
12306 -- Remove procedure calls, which syntactically cannot appear in
12307 -- this context, but which cannot be removed by type checking,
12308 -- because the context does not impose a type.
12310 -- The node may be labelled overloaded, but still contain only one
12311 -- interpretation because others were discarded earlier. If this
12312 -- is the case, retain the single interpretation if legal.
12320 then
12321 -- More than one candidate interpretation is available
12329 -- When compiling for a system where Address is of a visible
12330 -- integer type, spurious ambiguities can be produced when
12331 -- arithmetic operations have a literal operand and return
12332 -- System.Address or a descendant of it. These ambiguities
12333 -- are usually resolved by the context, but for conversions
12334 -- there is no context type and the removal of the spurious
12335 -- operations must be done explicitly here.
12337 if not Address_Is_Private
12339 then
12364 Conversion_Error_N
12367 -- If the interpretation involves a standard operator, use
12368 -- the location of the type, which may be user-defined.
12372 else
12376 Conversion_Error_N -- CODEFIX
12381 else
12385 Conversion_Error_N -- CODEFIX
12397 -- Deal with conversion of integer type to address if the pragma
12398 -- Allow_Integer_Address is in effect. We convert the conversion to
12399 -- an unchecked conversion in this case and we are all done.
12407 -- If we are within a child unit, check whether the type of the
12408 -- expression has an ancestor in a parent unit, in which case it
12409 -- belongs to its derivation class even if the ancestor is private.
12410 -- See RM 7.3.1 (5.2/3).
12414 -- Numeric types
12418 -- A universal fixed expression can be converted to any numeric type
12423 -- Also no need to check when in an instance or inlined body, because
12424 -- the legality has been established when the template was analyzed.
12425 -- Furthermore, numeric conversions may occur where only a private
12426 -- view of the operand type is visible at the instantiation point.
12427 -- This results in a spurious error if we check that the operand type
12428 -- is a numeric type.
12430 -- Note: in a previous version of this unit, the following tests were
12431 -- applied only for generated code (Comes_From_Source set to False),
12432 -- but in fact the test is required for source code as well, since
12433 -- this situation can arise in source code.
12438 -- Otherwise we need the conversion check
12440 else
12441 return Conversion_Check
12443 or else
12449 -- Array types
12455 then
12456 Conversion_Error_N
12460 else
12464 -- Ada 2005 (AI-251): Internally generated conversions of access to
12465 -- interface types added to force the displacement of the pointer to
12466 -- reference the corresponding dispatch table.
12471 then
12474 -- Ada 2005 (AI-251): Anonymous access types where target references an
12475 -- interface type.
12479 E_Anonymous_Access_Type)
12481 then
12482 -- Check the static accessibility rule of 4.6(17). Note that the
12483 -- check is not enforced when within an instance body, since the
12484 -- RM requires such cases to be caught at run time.
12486 -- If the operand is a rewriting of an allocator no check is needed
12487 -- because there are no accessibility issues.
12495 then
12496 -- In an instance, this is a run-time check, but one we know
12497 -- will fail, so generate an appropriate warning. The raise
12498 -- will be generated by Expand_N_Type_Conversion.
12502 Conversion_Error_N
12504 Operand);
12507 else
12508 Conversion_Error_N
12510 Operand);
12514 -- Special accessibility checks are needed in the case of access
12515 -- discriminants declared for a limited type.
12519 then
12520 -- When the operand is a selected access discriminant the check
12521 -- needs to be made against the level of the object denoted by
12522 -- the prefix of the selected name (Object_Access_Level handles
12523 -- checking the prefix of the operand for this case).
12528 then
12529 -- In an instance, this is a run-time check, but one we know
12530 -- will fail, so generate an appropriate warning. The raise
12531 -- will be generated by Expand_N_Type_Conversion.
12535 Conversion_Error_N
12540 -- Real error if not in instance body
12542 else
12543 Conversion_Error_N
12550 -- The case of a reference to an access discriminant from
12551 -- within a limited type declaration (which will appear as
12552 -- a discriminal) is always illegal because the level of the
12553 -- discriminant is considered to be deeper than any (nameable)
12554 -- access type.
12558 and then
12561 then
12562 Conversion_Error_N
12564 Operand);
12572 -- General and anonymous access types
12575 E_Anonymous_Access_Type)
12576 and then
12577 Conversion_Check
12579 and then not
12581 E_Access_Protected_Subprogram_Type),
12583 then
12586 then
12587 Conversion_Error_N
12592 -- Check the static accessibility rule of 4.6(17). Note that the
12593 -- check is not enforced when within an instance body, since the RM
12594 -- requires such cases to be caught at run time.
12599 N_Object_Declaration
12600 then
12601 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12602 -- conversions from an anonymous access type to a named general
12603 -- access type. Such conversions are not allowed in the case of
12604 -- access parameters and stand-alone objects of an anonymous
12605 -- access type. The implicit conversion case is recognized by
12606 -- testing that Comes_From_Source is False and that it's been
12607 -- rewritten. The Comes_From_Source test isn't sufficient because
12608 -- nodes in inlined calls to predefined library routines can have
12609 -- Comes_From_Source set to False. (Is there a better way to test
12610 -- for implicit conversions???)
12617 then
12620 -- Implicit conversions aren't allowed for objects of an
12621 -- anonymous access type, since such objects have nonstatic
12622 -- levels in Ada 2012.
12625 N_Object_Declaration
12626 then
12627 Conversion_Error_N
12632 -- Implicit conversions aren't allowed for anonymous access
12633 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12634 -- is done to exclude anonymous access results.
12638 N_Function_Specification,
12639 N_Procedure_Specification)
12640 then
12641 Conversion_Error_N
12646 -- This is a case where there's an enclosing object whose
12647 -- to which the "statically deeper than" relationship does
12648 -- not apply (such as an access discriminant selected from
12649 -- a dereference of an access parameter).
12653 then
12654 Conversion_Error_N
12659 -- In other cases, the level of the operand's type must be
12660 -- statically less deep than that of the target type, else
12661 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12665 then
12666 Conversion_Error_N
12675 then
12676 -- In an instance, this is a run-time check, but one we know
12677 -- will fail, so generate an appropriate warning. The raise
12678 -- will be generated by Expand_N_Type_Conversion.
12682 Conversion_Error_N
12684 Operand);
12687 -- If not in an instance body, this is a real error
12689 else
12690 -- Avoid generation of spurious error message
12693 Conversion_Error_N
12695 Operand);
12701 -- Special accessibility checks are needed in the case of access
12702 -- discriminants declared for a limited type.
12706 then
12707 -- When the operand is a selected access discriminant the check
12708 -- needs to be made against the level of the object denoted by
12709 -- the prefix of the selected name (Object_Access_Level handles
12710 -- checking the prefix of the operand for this case).
12715 then
12716 -- In an instance, this is a run-time check, but one we know
12717 -- will fail, so generate an appropriate warning. The raise
12718 -- will be generated by Expand_N_Type_Conversion.
12722 Conversion_Error_N
12727 -- If not in an instance body, this is a real error
12729 else
12730 Conversion_Error_N
12737 -- The case of a reference to an access discriminant from
12738 -- within a limited type declaration (which will appear as
12739 -- a discriminal) is always illegal because the level of the
12740 -- discriminant is considered to be deeper than any (nameable)
12741 -- access type.
12744 and then
12747 then
12748 Conversion_Error_N
12750 Operand);
12756 -- In the presence of limited_with clauses we have to use nonlimited
12757 -- views, if available.
12761 -- Helper function to handle limited views
12763 --------------------------
12764 -- Full_Designated_Type --
12765 --------------------------
12770 begin
12771 -- Handle the limited view of a type
12775 then
12777 else
12782 -- Local Declarations
12790 -- Start of processing for Check_Limited
12792 begin
12796 else
12798 Conversion_Error_NE
12803 -- Ada 2005 AI-384: legality rule is symmetric in both
12804 -- designated types. The conversion is legal (with possible
12805 -- constraint check) if either designated type is
12806 -- unconstrained.
12809 or else
12811 and then
12814 then
12815 -- Special case, if Value_Size has been used to make the
12816 -- sizes different, the conversion is not allowed even
12817 -- though the subtypes statically match.
12822 then
12823 Conversion_Error_NE
12826 Conversion_Error_NE
12831 -- Normal case where conversion is allowed
12833 else
12837 else
12838 Error_Msg_NE
12846 -- Access to subprogram types. If the operand is an access parameter,
12847 -- the type has a deeper accessibility that any master, and cannot be
12848 -- assigned. We must make an exception if the conversion is part of an
12849 -- assignment and the target is the return object of an extended return
12850 -- statement, because in that case the accessibility check takes place
12851 -- after the return.
12855 -- Note: this test of Opnd_Type is there to prevent entering this
12856 -- branch in the case of a remote access to subprogram type, which
12857 -- is internally represented as an E_Record_Type.
12860 then
12864 and then
12868 then
12869 Conversion_Error_N
12871 Operand);
12872 Conversion_Error_N
12875 Operand);
12877 Error_Msg_NE
12882 -- Check that the designated types are subtype conformant
12888 -- Check the static accessibility rule of 4.6(20)
12892 then
12893 Conversion_Error_N
12895 Operand);
12897 -- Check that if the operand type is declared in a generic body,
12898 -- then the target type must be declared within that same body
12899 -- (enforces last sentence of 4.6(20)).
12902 declare
12908 begin
12915 Conversion_Error_N
12924 -- Remote access to subprogram types
12928 then
12929 -- It is valid to convert from one RAS type to another provided
12930 -- that their specification statically match.
12932 -- Note: at this point, remote access to subprogram types have been
12933 -- expanded to their E_Record_Type representation, and we need to
12934 -- go back to the original access type definition using the
12935 -- Corresponding_Remote_Type attribute in order to check that the
12936 -- designated profiles match.
12941 Check_Subtype_Conformant
12944 Old_Id =>
12946 Err_Loc =>
12947 N);
12950 -- If it was legal in the generic, it's legal in the instance
12955 -- If both are tagged types, check legality of view conversions
12958 and then
12960 then
12963 -- Types derived from the same root type are convertible
12968 -- In an instance or an inlined body, there may be inconsistent views of
12969 -- the same type, or of types derived from a common root.
12972 and then
12975 then
12978 -- Special check for common access type error case
12982 then
12984 Conversion_Error_NE -- CODEFIX
12988 -- Here we have a real conversion error
12990 else
12991 Conversion_Error_NE