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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) 1992-2022, 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 ------------------------------------------------------------------------------
94 -----------------------
95 -- Local Subprograms --
96 -----------------------
98 -- Second pass (top-down) type checking and overload resolution procedures
99 -- Typ is the type required by context. These procedures propagate the
100 -- type information recursively to the descendants of N. If the node is not
101 -- overloaded, its Etype is established in the first pass. If overloaded,
102 -- the Resolve routines set the correct type. For arithmetic operators, the
103 -- Etype is the base type of the context.
105 -- Note that Resolve_Attribute is separated off in Sem_Attr
107 function Has_Applicable_User_Defined_Literal
110 -- If N is a literal or a named number, check whether Typ
111 -- has a user-defined literal aspect that can apply to N.
112 -- If present, replace N with a call to the corresponding
113 -- function and return True.
116 -- Enforce the restrictions on the use of discriminants when constraining
117 -- a component of a discriminated type (record or concurrent type).
120 -- Given a node for an operator associated with type T, check that the
121 -- operator is visible. Operators all of whose operands are universal must
122 -- be checked for visibility during resolution because their type is not
123 -- determinable based on their operands.
125 procedure Check_Fully_Declared_Prefix
128 -- Check that the type of the prefix of a dereference is not incomplete
131 -- Given a call node, Call, which is known to occur immediately within the
132 -- subprogram being called, determines whether it is a detectable case of
133 -- an infinite recursion, and if so, outputs appropriate messages. Returns
134 -- True if an infinite recursion is detected, and False otherwise.
137 -- N is the node for a logical operator. If the operator is predefined, and
138 -- the root type of the operands is Standard.Boolean, then a check is made
139 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
140 -- the style check for Style_Check_Boolean_And_Or.
143 -- N is either an indexed component or a selected component. This function
144 -- returns true if the prefix denotes an atomic object that has an address
145 -- clause (the case in which we may want to issue a warning).
148 -- Determine whether E is an access type declared by an access declaration,
149 -- and not an (anonymous) allocator type.
152 -- Utility to check whether the entity for an operator is a predefined
153 -- operator, in which case the expression is left as an operator in the
154 -- tree (else it is rewritten into a call). An instance of an intrinsic
155 -- conversion operation may be given an operator name, but is not treated
156 -- like an operator. Note that an operator that is an imported back-end
157 -- builtin has convention Intrinsic, but is expected to be rewritten into
158 -- a call, so such an operator is not treated as predefined by this
159 -- predicate.
161 procedure Preanalyze_And_Resolve
165 -- Subsidiary of public versions of Preanalyze_And_Resolve.
168 -- If a default expression in entry call N depends on the discriminants
169 -- of the task, it must be replaced with a reference to the discriminant
170 -- of the task being called.
172 procedure Resolve_Op_Concat_Arg
177 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
178 -- concatenation operator. The operand is either of the array type or of
179 -- the component type. If the operand is an aggregate, and the component
180 -- type is composite, this is ambiguous if component type has aggregates.
183 -- Does the first part of the work of Resolve_Op_Concat
186 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
187 -- has been resolved. See Resolve_Op_Concat for details.
227 function Operator_Kind
230 -- Utility to map the name of an operator into the corresponding Node. Used
231 -- by other node rewriting procedures.
234 -- Resolve actuals of call, and add default expressions for missing ones.
235 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
236 -- called subprogram.
239 -- Called from Resolve_Call, when the prefix denotes an entry or element
240 -- of entry family. Actuals are resolved as for subprograms, and the node
241 -- is rebuilt as an entry call. Also called for protected operations. Typ
242 -- is the context type, which is used when the operation is a protected
243 -- function with no arguments, and the return value is indexed.
246 -- Called when P is the prefix of an indexed component, or of a selected
247 -- component, or of a slice. If P is of an access type, we unconditionally
248 -- rewrite it as an explicit dereference. This ensures that the expander
249 -- and the code generator have a fully explicit tree to work with.
252 -- A call to a user-defined intrinsic operator is rewritten as a call to
253 -- the corresponding predefined operator, with suitable conversions. Note
254 -- that this applies only for intrinsic operators that denote predefined
255 -- operators, not ones that are intrinsic imports of back-end builtins.
258 -- Ditto, for arithmetic unary operators
261 -- If an operator node resolves to a call to a user-defined operator,
262 -- rewrite the node as a function call.
264 procedure Make_Call_Into_Operator
268 -- Inverse transformation: if an operator is given in functional notation,
269 -- then after resolving the node, transform into an operator node, so that
270 -- operands are resolved properly. Recall that predefined operators do not
271 -- have a full signature and special resolution rules apply.
273 procedure Rewrite_Renamed_Operator
277 -- An operator can rename another, e.g. in an instantiation. In that
278 -- case, the proper operator node must be constructed and resolved.
281 -- The String_Literal_Subtype is built for all strings that are not
282 -- operands of a static concatenation operation. If the argument is not
283 -- a N_String_Literal node, then the call has no effect.
286 -- Build subtype of array type, with the range specified by the slice
289 -- Called after N has been resolved and evaluated, but before range checks
290 -- have been applied. This rewrites the conversion into a simpler form.
293 -- A universal_fixed expression in an universal context is unambiguous if
294 -- there is only one applicable fixed point type. Determining whether there
295 -- is only one requires a search over all visible entities, and happens
296 -- only in very pathological cases (see 6115-006).
298 function Try_User_Defined_Literal
301 -- If an operator node has a literal operand, check whether the type
302 -- of the context, or the type of the other operand has a user-defined
303 -- literal aspect that can be applied to the literal to resolve the node.
304 -- If such aspect exists, replace literal with a call to the
305 -- corresponding function and return True, return false otherwise.
307 -------------------------
308 -- Ambiguous_Character --
309 -------------------------
314 begin
318 -- First the ones in Standard
323 -- Include Wide_Wide_Character in Ada 2005 mode
329 -- Now any other types that match
339 -------------------------
340 -- Analyze_And_Resolve --
341 -------------------------
344 begin
350 begin
355 -- Versions with check(s) suppressed
357 procedure Analyze_And_Resolve
361 is
364 begin
366 declare
368 begin
374 else
375 declare
377 begin
385 and then Scope_Is_Transient
386 then
387 -- This can only happen if a transient scope was created for an inner
388 -- expression, which will be removed upon completion of the analysis
389 -- of an enclosing construct. The transient scope must have the
390 -- suppress status of the enclosing environment, not of this Analyze
391 -- call.
394 Scope_Suppress;
398 procedure Analyze_And_Resolve
401 is
404 begin
406 declare
408 begin
414 else
415 declare
417 begin
426 Scope_Suppress;
430 -------------------------------------
431 -- Has_Applicable_User_Defined_Literal --
432 -------------------------------------
434 function Has_Applicable_User_Defined_Literal
437 is
439 Literal_Aspect_Map :
459 begin
461 and then Present
463 or else
466 and then
467 Present
468 (Find_Aspect
470 then
471 Lit_Aspect :=
475 Callee :=
482 then
483 Callee :=
484 Corresponding_Primitive_Op
489 -- Handle an identifier that denotes a named number.
496 Start_String;
497 Store_String_Chars
502 else
504 Start_String;
510 Store_String_Chars
514 -- Note: Set_Etype is called below on Param1
517 Start_String;
518 Store_String_Chars
527 else
528 Error_Msg_NE
538 else
539 Param1 :=
540 Make_String_Literal
545 Call :=
546 Make_Function_Call
556 else
562 -- Conversion not needed if the result type of the call is class-wide
563 -- or if the result type matches the context type.
567 then
568 -- Conversion may be needed in case of an inherited
569 -- aspect of a derived type. For a null extension, we
570 -- use a null extension aggregate instead because the
571 -- downward type conversion would be illegal.
573 if Is_Null_Extension_Of
576 then
580 else
589 else
594 ----------------------------
595 -- Check_Discriminant_Use --
596 ----------------------------
604 begin
605 -- Any use in a spec-expression is legal
612 -- Discriminant cannot be used to constrain a scalar type
619 then
624 -- The following check catches the unusual case where a
625 -- discriminant appears within an index constraint that is part
626 -- of a larger expression within a constraint on a component,
627 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
628 -- check case of record components, and note that a similar check
629 -- should also apply in the case of discriminant constraints
630 -- below. ???
632 -- Note that the check for N_Subtype_Declaration below is to
633 -- detect the valid use of discriminants in the constraints of a
634 -- subtype declaration when this subtype declaration appears
635 -- inside the scope of a record type (which is syntactically
636 -- illegal, but which may be created as part of derived type
637 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
638 -- for more info.
642 and then not
644 and then
646 | N_Subtype_Declaration
648 then
649 Error_Msg_N
654 -- Detect a common error:
656 -- type R (D : Positive := 100) is record
657 -- Name : String (1 .. D);
658 -- end record;
660 -- The default value causes an object of type R to be allocated
661 -- with room for Positive'Last characters. The RM does not mandate
662 -- the allocation of the maximum size, but that is what GNAT does
663 -- so we should warn the programmer that there is a problem.
672 -- Return True if type T has a large enough range that any
673 -- array whose index type covered the whole range of the type
674 -- would likely raise Storage_Error.
676 ------------------------
677 -- Large_Storage_Type --
678 ------------------------
681 begin
682 -- The type is considered large if its bounds are known at
683 -- compile time and if it requires at least as many bits as
684 -- a Positive to store the possible values.
688 and then
693 -- Start of processing for Check_Large
695 begin
696 -- Check that the Disc has a large range
702 -- If the enclosing type is limited, we allocate only the
703 -- default value, not the maximum, and there is no need for
704 -- a warning.
710 -- Check that it is the high bound
714 then
718 -- Check the array allows a large range at this bound. First
719 -- find the array
733 -- Next, find the dimension
741 loop
750 -- Now, check the dimension has a large range
756 -- Warn about the danger
758 Error_Msg_N
768 -- Legal case is in index or discriminant constraint
771 | N_Discriminant_Association
772 then
774 Error_Msg_N
779 then
780 Error_Msg_N
786 -- Otherwise, context is an expression. It should not be within (i.e. a
787 -- subexpression of) a constraint for a component.
789 else
793 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
794 loop
800 -- If the discriminant is used in an expression that is a bound of a
801 -- scalar type, an Itype is created and the bounds are attached to
802 -- its range, not to the original subtype indication. Such use is of
803 -- course a double fault.
807 | N_Derived_Type_Definition
810 -- The constraint itself may be given by a subtype indication,
811 -- rather than by a more common discrete range.
814 and then
818 then
819 Error_Msg_N
825 --------------------------------
826 -- Check_For_Visible_Operator --
827 --------------------------------
830 begin
834 then
835 Error_Msg_NE -- CODEFIX
837 Error_Msg_N -- CODEFIX
842 ---------------------------------
843 -- Check_Fully_Declared_Prefix --
844 ---------------------------------
846 procedure Check_Fully_Declared_Prefix
849 is
850 begin
851 -- Check that the designated type of the prefix of a dereference is
852 -- not an incomplete type. This cannot be done unconditionally, because
853 -- dereferences of private types are legal in default expressions. This
854 -- case is taken care of in Check_Fully_Declared, called below. There
855 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
857 -- This consideration also applies to similar checks for allocators,
858 -- qualified expressions, and type conversions.
860 -- An additional exception concerns other per-object expressions that
861 -- are not directly related to component declarations, in particular
862 -- representation pragmas for tasks. These will be per-object
863 -- expressions if they depend on discriminants or some global entity.
864 -- If the task has access discriminants, the designated type may be
865 -- incomplete at the point the expression is resolved. This resolution
866 -- takes place within the body of the initialization procedure, where
867 -- the discriminant is replaced by its discriminal.
871 then
874 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
875 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
876 -- Analyze_Object_Renaming, and Freeze_Entity.
882 E_Incomplete_Type
884 then
886 else
891 ------------------------------
892 -- Check_Infinite_Recursion --
893 ------------------------------
897 -- Return the nearest enclosing declaration or statement that houses
898 -- arbitrary node N.
901 -- Determine whether call N invokes the related enclosing subprogram
902 -- with actuals that differ from the subprogram's formals.
905 -- Determine whether arbitrary node N denotes a conditional construct
908 -- Determine whether arbitrary node N denotes a control flow statement
909 -- or a construct that may contains such a statement.
912 -- Determine whether arbitrary node N appears immediately within the
913 -- statements of an entry or subprogram body.
916 -- Determine whether arbitrary node N appears immediately within the
917 -- body of an entry or subprogram, and is preceded by a single raise
918 -- statement.
921 -- Determine whether arbitrary node N denotes a raise statement
924 -- Determine whether arbitrary node N is the sole source statement in
925 -- the body of the enclosing subprogram.
928 -- Determine whether arbitrary node N is preceded by a control flow
929 -- statement.
932 -- Determine whether arbitrary node N appears within a conditional
933 -- construct.
935 ----------------------------------------
936 -- Enclosing_Declaration_Or_Statement --
937 ----------------------------------------
939 function Enclosing_Declaration_Or_Statement
941 is
944 begin
950 -- Prevent the search from going too far
962 --------------------------------------
963 -- Invoked_With_Different_Arguments --
964 --------------------------------------
972 begin
973 -- Determine whether the formals of the invoked subprogram are not
974 -- used as actuals in the call.
980 -- The current actual does not match the current formal
984 then
995 ------------------------------
996 -- Is_Conditional_Statement --
997 ------------------------------
1000 begin
1001 return
1003 | N_Case_Expression
1004 | N_Case_Statement
1005 | N_If_Expression
1006 | N_If_Statement
1007 | N_Or_Else;
1010 -------------------------------
1011 -- Is_Control_Flow_Statement --
1012 -------------------------------
1015 begin
1016 -- It is assumed that all statements may affect the control flow in
1017 -- some way. A raise statement may be expanded into a non-statement
1018 -- node.
1023 --------------------------------
1024 -- Is_Immediately_Within_Body --
1025 --------------------------------
1030 begin
1031 return
1038 --------------------
1039 -- Is_Raise_Idiom --
1040 --------------------
1046 begin
1049 -- Assume that no raise statement has been seen yet
1053 -- Examine the statements preceding the input node, skipping
1054 -- internally-generated constructs.
1059 -- Multiple raise statements violate the idiom
1075 -- At this point the node must be preceded by a raise statement,
1076 -- and the raise statement has to be the sole statement within
1077 -- the enclosing entry or subprogram body.
1079 return
1086 ------------------------
1087 -- Is_Raise_Statement --
1088 ------------------------
1091 begin
1092 -- A raise statement may be transfomed into a Raise_xxx_Error node
1094 return
1099 -----------------------
1100 -- Is_Sole_Statement --
1101 -----------------------
1106 begin
1107 -- The input node appears within the statements of an entry or
1108 -- subprogram body. Examine the statements preceding the node.
1115 -- The statement is preceded by another statement or a source
1116 -- construct. This indicates that the node does not appear by
1117 -- itself.
1121 then
1131 -- The input node is within a construct nested inside the entry or
1132 -- subprogram body.
1137 ----------------------------------------
1138 -- Preceded_By_Control_Flow_Statement --
1139 ----------------------------------------
1141 function Preceded_By_Control_Flow_Statement
1143 is
1146 begin
1150 -- Examine the statements preceding the input node
1163 -- Assume that the node is part of some control flow statement
1168 ----------------------------------
1169 -- Within_Conditional_Statement --
1170 ----------------------------------
1175 begin
1181 -- Prevent the search from going too far
1193 -- Local variables
1198 -- Start of processing for Check_Infinite_Recursion
1200 begin
1201 -- The call is assumed to be safe when the enclosing subprogram is
1202 -- invoked with actuals other than its formals.
1203 --
1204 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1205 -- begin
1206 -- ...
1207 -- Proc (A1, A2, ..., AN);
1208 -- ...
1209 -- end Proc;
1214 -- The call is assumed to be safe when the invocation of the enclosing
1215 -- subprogram depends on a conditional statement.
1216 --
1217 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1218 -- begin
1219 -- ...
1220 -- if Some_Condition then
1221 -- Proc (F1, F2, ..., FN);
1222 -- end if;
1223 -- ...
1224 -- end Proc;
1229 -- The context of the call is assumed to be safe when the invocation of
1230 -- the enclosing subprogram is preceded by some control flow statement.
1231 --
1232 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1233 -- begin
1234 -- ...
1235 -- if Some_Condition then
1236 -- ...
1237 -- end if;
1238 -- ...
1239 -- Proc (F1, F2, ..., FN);
1240 -- ...
1241 -- end Proc;
1246 -- Detect an idiom where the context of the call is preceded by a single
1247 -- raise statement.
1248 --
1249 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1250 -- begin
1251 -- raise ...;
1252 -- Proc (F1, F2, ..., FN);
1253 -- end Proc;
1259 -- At this point it is certain that infinite recursion will take place
1260 -- as long as the call is executed. Detect a case where the context of
1261 -- the call is the sole source statement within the subprogram body.
1262 --
1263 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1264 -- begin
1265 -- Proc (F1, F2, ..., FN);
1266 -- end Proc;
1267 --
1268 -- Install an explicit raise to prevent the infinite recursion.
1279 -- Otherwise infinite recursion could take place, considering other flow
1280 -- control constructs such as gotos, exit statements, etc.
1282 else
1291 ---------------------------------------
1292 -- Check_No_Direct_Boolean_Operators --
1293 ---------------------------------------
1296 begin
1299 then
1300 -- Restriction only applies to original source code
1307 -- Do style check (but skip if in instance, error is on template)
1316 ------------------------------
1317 -- Check_Parameterless_Call --
1318 ------------------------------
1324 -- If the prefix is of an access_to_subprogram type, the node must be
1325 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1326 -- interpretations are access to subprograms.
1328 ---------------------------
1329 -- Prefix_Is_Access_Subp --
1330 ---------------------------
1336 begin
1337 -- If the context is an attribute reference that can apply to
1338 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1342 in Name_Address | Name_Code_Address | Name_Access
1343 then
1348 return
1351 else
1356 then
1367 -- Start of processing for Check_Parameterless_Call
1369 begin
1370 -- Defend against junk stuff if errors already detected
1377 then
1384 -- If the context expects a value, and the name is a procedure, this is
1385 -- most likely a missing 'Access. Don't try to resolve the parameterless
1386 -- call, error will be caught when the outer call is analyzed.
1391 and then
1393 | N_Function_Call
1394 | N_Procedure_Call_Statement
1395 then
1399 -- Rewrite as call if overloadable entity that is (or could be, in the
1400 -- overloaded case) a function call. If we know for sure that the entity
1401 -- is an enumeration literal, we do not rewrite it.
1403 -- If the entity is the name of an operator, it cannot be a call because
1404 -- operators cannot have default parameters. In this case, this must be
1405 -- a string whose contents coincide with an operator name. Set the kind
1406 -- of the node appropriately.
1414 -- Rewrite as call if it is an explicit dereference of an expression of
1415 -- a subprogram access type, and the subprogram type is not that of a
1416 -- procedure or entry.
1418 or else
1421 -- Rewrite as call if it is a selected component which is a function,
1422 -- this is the case of a call to a protected function (which may be
1423 -- overloaded with other protected operations).
1425 or else
1428 or else
1430 E_Entry | E_Procedure
1433 -- If one of the above three conditions is met, rewrite as call. Apply
1434 -- the rewriting only once.
1436 then
1439 then
1441 -- This may be a prefixed call that was not fully analyzed, e.g.
1442 -- an actual in an instance.
1447 then
1455 -- The node is the name of the parameterless call. Preserve its
1456 -- descendants, which may be complex expressions.
1460 -- If overloaded, overload set belongs to new copy
1464 -- Change node to parameterless function call (note that the
1465 -- Parameter_Associations associations field is left set to Empty,
1466 -- its normal default value since there are no parameters)
1486 --------------------------------
1487 -- Is_Atomic_Ref_With_Address --
1488 --------------------------------
1493 begin
1497 else
1498 declare
1501 begin
1509 -----------------------------
1510 -- Is_Definite_Access_Type --
1511 -----------------------------
1515 begin
1521 ----------------------
1522 -- Is_Predefined_Op --
1523 ----------------------
1526 begin
1527 -- Predefined operators are intrinsic subprograms
1533 -- A call to a back-end builtin is never a predefined operator
1544 -----------------------------
1545 -- Make_Call_Into_Operator --
1546 -----------------------------
1548 procedure Make_Call_Into_Operator
1552 is
1567 -- If the operand is not universal, and the operator is given by an
1568 -- expanded name, verify that the operand has an interpretation with a
1569 -- type defined in the given scope of the operator.
1572 -- Find a type of the given class in package Pack that contains the
1573 -- operator.
1575 ---------------------------
1576 -- Operand_Type_In_Scope --
1577 ---------------------------
1584 begin
1588 else
1602 ---------------
1603 -- Type_In_P --
1604 ---------------
1610 -- Verify that node is not part of the type declaration for the
1611 -- candidate type, which would otherwise be invisible.
1613 -------------
1614 -- In_Decl --
1615 -------------
1621 begin
1630 else
1633 loop
1636 else
1645 -- Start of processing for Type_In_P
1647 begin
1648 -- If the context type is declared in the prefix package, this is the
1649 -- desired base type.
1654 else
1668 -- Start of processing for Make_Call_Into_Operator
1670 begin
1673 -- Preserve the Comes_From_Source flag on the result if the original
1674 -- call came from source. Although it is not strictly the case that the
1675 -- operator as such comes from the source, logically it corresponds
1676 -- exactly to the function call in the source, so it should be marked
1677 -- this way (e.g. to make sure that validity checks work fine).
1681 -- Ensure that the corresponding operator has the same parent as the
1682 -- original call. This guarantees that parent traversals performed by
1683 -- the ABE mechanism succeed.
1687 -- Binary operator
1697 -- Unary operator
1699 else
1705 -- If the operator is denoted by an expanded name, and the prefix is
1706 -- not Standard, but the operator is a predefined one whose scope is
1707 -- Standard, then this is an implicit_operator, inserted as an
1708 -- interpretation by the procedure of the same name. This procedure
1709 -- overestimates the presence of implicit operators, because it does
1710 -- not examine the type of the operands. Verify now that the operand
1711 -- type appears in the given scope. If right operand is universal,
1712 -- check the other operand. In the case of concatenation, either
1713 -- argument can be the component type, so check the type of the result.
1714 -- If both arguments are literals, look for a type of the right kind
1715 -- defined in the given scope. This elaborate nonsense is brought to
1716 -- you courtesy of b33302a. The type itself must be frozen, so we must
1717 -- find the type of the proper class in the given scope.
1719 -- A final wrinkle is the multiplication operator for fixed point types,
1720 -- which is defined in Standard only, and not in the scope of the
1721 -- fixed point type itself.
1726 -- If this is a package renaming, get renamed entity, which will be
1727 -- the scope of the operands if operaton is type-correct.
1733 -- If the entity being called is defined in the given package, it is
1734 -- a renaming of a predefined operator, and known to be legal.
1738 then
1741 -- Visibility does not need to be checked in an instance: if the
1742 -- operator was not visible in the generic it has been diagnosed
1743 -- already, else there is an implicit copy of it in the instance.
1751 then
1756 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1757 -- available.
1763 then
1766 else
1775 and then Is_Binary
1777 then
1783 -- Verify that the scope contains a type that corresponds to
1784 -- the given literal. Optimize the case where Pack is Standard.
1805 else
1814 else
1823 then
1826 -- If the type is defined elsewhere, and the operator is not
1827 -- defined in the given scope (by a renaming declaration, e.g.)
1828 -- then this is an error as well. If an extension of System is
1829 -- present, and the type may be defined there, Pack must be
1830 -- System itself.
1837 then
1840 else
1846 then
1853 Error_Msg_NE
1858 -- Detect a mismatch between the context type and the result type
1859 -- in the named package, which is otherwise not detected if the
1860 -- operands are universal. Check is only needed if source entity is
1861 -- an operator, not a function that renames an operator.
1868 and then not In_Instance
1869 then
1872 then
1873 -- Already checked above
1877 -- Operator may be defined in an extension of System
1882 then
1885 else
1886 -- Could we use Wrong_Type here??? (this would require setting
1887 -- Etype (N) to the actual type found where Typ was expected).
1898 else
1902 -- If this is a call to a function that renames a predefined equality,
1903 -- the renaming declaration provides a type that must be used to
1904 -- resolve the operands. This must be done now because resolution of
1905 -- the equality node will not resolve any remaining ambiguity, and it
1906 -- assumes that the first operand is not overloaded.
1911 then
1921 -- If this is an arithmetic operator and the result type is private,
1922 -- the operands and the result must be wrapped in conversion to
1923 -- expose the underlying numeric type and expand the proper checks,
1924 -- e.g. on division.
1928 when N_Op_Add
1929 | N_Op_Divide
1930 | N_Op_Expon
1931 | N_Op_Mod
1932 | N_Op_Multiply
1933 | N_Op_Rem
1934 | N_Op_Subtract
1935 =>
1938 when N_Op_Abs
1939 | N_Op_Minus
1940 | N_Op_Plus
1941 =>
1947 else
1952 -------------------
1953 -- Operator_Kind --
1954 -------------------
1956 function Operator_Kind
1959 is
1962 begin
1963 -- Use CASE statement or array???
2000 else
2004 -- Unary operators
2006 else
2015 else
2023 ----------------------------
2024 -- Preanalyze_And_Resolve --
2025 ----------------------------
2027 procedure Preanalyze_And_Resolve
2031 is
2035 Inside_Preanalysis_Without_Freezing;
2036 begin
2041 Inside_Preanalysis_Without_Freezing :=
2048 -- Normally, we suppress all checks for this preanalysis. There is no
2049 -- point in processing them now, since they will be applied properly
2050 -- and in the proper location when the default expressions reanalyzed
2051 -- and reexpanded later on. We will also have more information at that
2052 -- point for possible suppression of individual checks.
2054 -- However, in SPARK mode, most expansion is suppressed, and this
2055 -- later reanalysis and reexpansion may not occur. SPARK mode does
2056 -- require the setting of checking flags for proof purposes, so we
2057 -- do the SPARK preanalysis without suppressing checks.
2059 -- This special handling for SPARK mode is required for example in the
2060 -- case of Ada 2012 constructs such as quantified expressions, which are
2061 -- expanded in two separate steps.
2063 -- We also do not want to suppress checks if we are not dealing
2064 -- with a default expression. One such case that is known to reach
2065 -- this point is the expression of an expression function.
2069 else
2073 Expander_Mode_Restore;
2078 Inside_Preanalysis_Without_Freezing :=
2082 pragma Assert
2086 ----------------------------
2087 -- Preanalyze_And_Resolve --
2088 ----------------------------
2091 begin
2095 -- Version without context type
2100 begin
2107 Expander_Mode_Restore;
2111 ------------------------------------------
2112 -- Preanalyze_With_Freezing_And_Resolve --
2113 ------------------------------------------
2115 procedure Preanalyze_With_Freezing_And_Resolve
2118 is
2119 begin
2123 ----------------------------------
2124 -- Replace_Actual_Discriminants --
2125 ----------------------------------
2132 -- Comment needed???
2134 -------------------
2135 -- Process_Discr --
2136 -------------------
2141 begin
2147 then
2163 -- Start of processing for Replace_Actual_Discriminants
2165 begin
2169 -- Allow the replacement of concurrent discriminants in GNATprove even
2170 -- though this is a light expansion activity. Note that generic units
2171 -- are not modified.
2176 else
2192 -------------
2193 -- Resolve --
2194 -------------
2210 -- Determine whether a node comes from a predefined library unit or
2211 -- Standard.
2214 -- Try and fix up a literal so that it matches its expected type. New
2215 -- literals are manufactured if necessary to avoid cascaded errors.
2218 -- Additional diagnostics when an ambiguous call has an ambiguous
2219 -- argument (typically a controlling actual).
2222 -- Called when attempt at resolving current expression fails
2224 ------------------------------------
2225 -- Comes_From_Predefined_Lib_Unit --
2226 -------------------------------------
2229 begin
2230 return
2234 --------------------
2235 -- Patch_Up_Value --
2236 --------------------
2239 begin
2256 then
2261 Char_Literal_Value =>
2277 -------------------------------
2278 -- Report_Ambiguous_Argument --
2279 -------------------------------
2286 begin
2290 then
2293 -- Examine possible interpretations, and adapt the message
2294 -- for inherited subprograms declared by a type derivation.
2302 else
2310 -- Additional message and hint if the ambiguity involves an Ada 2022
2311 -- container aggregate.
2316 -----------------------
2317 -- Resolution_Failed --
2318 -----------------------
2321 begin
2324 -- Set the type to the desired one to minimize cascaded errors. Note
2325 -- that this is an approximation and does not work in all cases.
2332 -- The caller will return without calling the expander, so we need
2333 -- to set the analyzed flag. Note that it is fine to set Analyzed
2334 -- to True even if we are in the middle of a shallow analysis,
2335 -- (see the spec of sem for more details) since this is an error
2336 -- situation anyway, and there is no point in repeating the
2337 -- analysis later (indeed it won't work to repeat it later, since
2338 -- we haven't got a clear resolution of which entity is being
2339 -- referenced.)
2345 -- Start of processing for Resolve
2347 begin
2352 -- Access attribute on remote subprogram cannot be used for a non-remote
2353 -- access-to-subprogram type.
2357 | Name_Unrestricted_Access
2358 | Name_Unchecked_Access
2364 then
2365 Error_Msg_N
2371 -- If the context is a Remote_Access_To_Subprogram, access attributes
2372 -- must be resolved with the corresponding fat pointer. There is no need
2373 -- to check for the attribute name since the return type of an
2374 -- attribute is never a remote type.
2379 then
2380 declare
2388 begin
2389 -- Check that Typ is a remote access-to-subprogram type
2393 -- Prefix (N) must statically denote a remote subprogram
2394 -- declared in a package specification.
2398 Attr = Attribute_Unrestricted_Access
2399 then
2414 or else
2416 then
2418 Error_Msg_N
2420 N);
2423 -- If we are generating code in distributed mode, perform
2424 -- semantic checks against corresponding remote entities.
2426 if Expander_Active
2428 then
2429 Check_Subtype_Conformant
2431 Old_Id => Designated_Type
2457 then
2462 -- Return if already analyzed
2469 -- Any case of Any_Type as the Etype value means that we had a
2470 -- previous error.
2479 -- The resolution of an Expression_With_Actions is determined by
2480 -- its Expression, but if the node comes from source it is a
2481 -- Declare_Expression and requires scope management.
2486 else
2493 -- If not overloaded, then we know the type, and all that needs doing
2494 -- is to check that this type is compatible with the context.
2500 -- In the overloaded case, we must select the interpretation that
2501 -- is compatible with the context (i.e. the type passed to Resolve)
2503 else
2504 -- Loop through possible interpretations
2513 -- We are only interested in interpretations that are compatible
2514 -- with the expected type, any other interpretations are ignored.
2519 Write_Eol;
2522 else
2523 -- Skip the current interpretation if it is disabled by an
2524 -- abstract operator. This action is performed only when the
2525 -- type against which we are resolving is the same as the
2526 -- type of the interpretation.
2532 then
2540 -- First matching interpretation
2548 -- Matching interpretation that is not the first, maybe an
2549 -- error, but there are some cases where preference rules are
2550 -- used to choose between the two possibilities. These and
2551 -- some more obscure cases are handled in Disambiguate.
2553 else
2554 -- If the current statement is part of a predefined library
2555 -- unit, then all interpretations which come from user level
2556 -- packages should not be considered. Check previous and
2557 -- current one.
2565 -- Previous interpretation must be discarded
2575 -- Otherwise apply further disambiguation steps
2580 -- Disambiguation has succeeded. Skip the remaining
2581 -- interpretations.
2591 else
2592 -- Before we issue an ambiguity complaint, check for the
2593 -- case of a subprogram call where at least one of the
2594 -- arguments is Any_Type, and if so suppress the message,
2595 -- since it is a cascaded error. This can also happen for
2596 -- a generalized indexing operation.
2601 then
2602 declare
2606 begin
2622 Write_Eol;
2635 then
2640 then
2644 -- Not that special case, so issue message using the flag
2645 -- Ambiguous to control printing of the header message
2646 -- only at the start of an ambiguous set.
2651 then
2652 Error_Msg_N
2655 else
2656 Error_Msg_NE -- CODEFIX
2664 Error_Msg_N
2666 else
2667 Error_Msg_N -- CODEFIX
2673 then
2674 Report_Ambiguous_Argument;
2680 -- By default, the error message refers to the candidate
2681 -- interpretation. But if it is a predefined operator, it
2682 -- is implicitly declared at the declaration of the type
2683 -- of the operand. Recover the sloc of that declaration
2684 -- for the error message.
2690 Standard_Standard
2691 then
2696 then
2704 Standard_Standard
2705 then
2710 then
2714 -- If this is an indirect call, use the subprogram_type
2715 -- in the message, to have a meaningful location. Also
2716 -- indicate if this is an inherited operation, created
2717 -- by a type declaration.
2722 then
2724 Error_Msg_Sloc :=
2726 else
2733 then
2734 -- Special-case the message for universal_fixed
2735 -- operators, which are not declared with the type
2736 -- of the operand, but appear forever in Standard.
2740 then
2741 Error_Msg_N
2744 else
2745 Error_Msg_N
2749 elsif
2751 then
2752 Error_Msg_N
2754 else
2755 Error_Msg_N -- CODEFIX
2762 -- We have a matching interpretation, Expr_Type is the type
2763 -- from this interpretation, and Seen is the entity.
2765 -- For an operator, just set the entity name. The type will be
2766 -- set by the specific operator resolution routine.
2773 | N_Character_Literal
2774 | N_Delta_Aggregate
2775 | N_If_Expression
2776 then
2779 -- AI05-0139-2: Expression is overloaded because type has
2780 -- implicit dereference. The context may be the one that
2781 -- requires implicit dereferemce.
2787 -- If the expression is an entity, generate a reference
2788 -- to it, as this is not done for an overloaded construct
2789 -- during analysis.
2793 then
2796 -- Examine access discriminants of entity type,
2797 -- to check whether one of them yields the
2798 -- expected type.
2800 declare
2804 begin
2825 then
2826 -- If the node is a general indexing, the dereference is
2827 -- is inserted when resolving the rewritten form, else
2828 -- insert it now.
2832 then
2836 -- For an explicit dereference, attribute reference, range,
2837 -- short-circuit form (which is not an operator node), or call
2838 -- with a name that is an explicit dereference, there is
2839 -- nothing to be done at this point.
2842 | N_And_Then
2843 | N_Explicit_Dereference
2844 | N_Identifier
2845 | N_Indexed_Component
2846 | N_Or_Else
2847 | N_Range
2848 | N_Selected_Component
2849 | N_Slice
2851 then
2854 -- For procedure or function calls, set the type of the name,
2855 -- and also the entity pointer for the prefix.
2859 then
2866 then
2871 -- For all other cases, just set the type of the Name
2873 else
2881 -- Move to next interpretation
2889 -- At this stage Found indicates whether or not an acceptable
2890 -- interpretation exists. If not, then we have an error, except that if
2891 -- the context is Any_Type as a result of some other error, then we
2892 -- suppress the error report.
2897 -- If type we are looking for is Void, then this is the procedure
2898 -- call case, and the error is simply that what we gave is not a
2899 -- procedure name (we think of procedure calls as expressions with
2900 -- types internally, but the user doesn't think of them this way).
2904 -- Special case message if function used as a procedure
2909 then
2910 Error_Msg_NE
2913 Error_Msg_N
2917 -- Otherwise give general message (not clear what cases this
2918 -- covers, but no harm in providing for them).
2920 else
2926 -- Otherwise we do have a subexpression with the wrong type
2928 -- Check for the case of an allocator which uses an access type
2929 -- instead of the designated type. This is a common error and we
2930 -- specialize the message, posting an error on the operand of the
2931 -- allocator, complaining that we expected the designated type of
2932 -- the allocator.
2938 then
2942 -- Check for view mismatch on Null in instances, for which the
2943 -- view-swapping mechanism has no identifier.
2949 then
2954 -- Check for an aggregate. Sometimes we can get bogus aggregates
2955 -- from misuse of parentheses, and we are about to complain about
2956 -- the aggregate without even looking inside it.
2958 -- Instead, if we have an aggregate of type Any_Composite, then
2959 -- analyze and resolve the component fields, and then only issue
2960 -- another message if we get no errors doing this (otherwise
2961 -- assume that the errors in the aggregate caused the problem).
2965 then
2968 then
2977 -- Disable expansion in any case. If there is a type mismatch
2978 -- it may be fatal to try to expand the aggregate. The flag
2979 -- would otherwise be set to false when the error is posted.
2983 declare
2985 -- Check one aggregate, and set Found to True if we have a
2986 -- definite error in any of its elements
2989 -- Check one element of aggregate and set Found to True if
2990 -- we definitely have an error in the element.
2992 ----------------
2993 -- Check_Aggr --
2994 ----------------
2999 begin
3012 -- If this is a default-initialized component, then
3013 -- there is nothing to check. The box will be
3014 -- replaced by the appropriate call during late
3015 -- expansion.
3019 then
3028 ----------------
3029 -- Check_Elmt --
3030 ----------------
3033 begin
3034 -- If we have a nested aggregate, go inside it (to
3035 -- attempt a naked analyze-resolve of the aggregate can
3036 -- cause undesirable cascaded errors). Do not resolve
3037 -- expression if it needs a type from context, as for
3038 -- integer * fixed expression.
3043 else
3048 then
3058 begin
3063 -- If node is a literal and context type has a user-defined
3064 -- literal aspect, rewrite node as a call to the corresponding
3065 -- function, which plays the role of an implicit conversion.
3068 N_Numeric_Or_String_Literal | N_Identifier
3070 then
3075 -- Looks like we have a type error, but check for special case
3076 -- of Address wanted, integer found, with the configuration pragma
3077 -- Allow_Integer_Address active. If we have this case, introduce
3078 -- an unchecked conversion to allow the integer expression to be
3079 -- treated as an Address. The reverse case of integer wanted,
3080 -- Address found, is treated in an analogous manner.
3087 -- Under relaxed RM semantics silently replace occurrences of null
3088 -- by System.Null_Address.
3096 -- That special Allow_Integer_Address check did not apply, so we
3097 -- have a real type error. If an error message was issued already,
3098 -- Found got reset to True, so if it's still False, issue standard
3099 -- Wrong_Type message.
3103 declare
3106 begin
3112 -- Protected operation: retrieve operation name
3116 else
3121 Error_Msg_NE
3127 declare
3131 begin
3138 Error_Msg_NE
3144 else
3148 -- Recognize the case of a quantified expression being mistaken
3149 -- for an iterated component association because the user
3150 -- forgot the "all" or "some" keyword after "for". Because the
3151 -- error message starts with "missing ALL", we automatically
3152 -- benefit from the associated CODEFIX, which requires that
3153 -- the message is located on the identifier following "for"
3154 -- in order for the CODEFIX to insert "all" in the right place.
3159 = N_Iterated_Component_Association
3161 then
3162 Error_Msg_N -- CODEFIX
3166 -- For an operator with no interpretation, check whether
3167 -- one of its operands may be a user-defined literal.
3171 then
3174 else
3180 Resolution_Failed;
3183 -- Test if we have more than one interpretation for the context
3186 Resolution_Failed;
3189 -- Only one interpretation
3191 else
3192 -- Prevent implicit conversions between access-to-subprogram types
3193 -- with different strub modes. Explicit conversions are acceptable in
3194 -- some circumstances. We don't have to be concerned about data or
3195 -- access-to-data types. Conversions between data types can safely
3196 -- drop or add strub attributes from types, because strub effects are
3197 -- associated with the locations rather than values. E.g., converting
3198 -- a hypothetical Strub_Integer variable to Integer would load the
3199 -- value from the variable, enabling stack scrabbing for the
3200 -- enclosing subprogram, and then convert the value to Integer. As
3201 -- for conversions between access-to-data types, that's no different
3202 -- from any other case of type punning.
3208 then
3209 Check_Same_Strub_Mode
3213 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3214 -- the "+" on T is abstract, and the operands are of universal type,
3215 -- the above code will have (incorrectly) resolved the "+" to the
3216 -- universal one in Standard. Therefore check for this case and give
3217 -- an error. We can't do this earlier, because it would cause legal
3218 -- cases to get errors (when some other type has an abstract "+").
3224 then
3229 then
3230 Nondispatching_Call_To_Abstract_Operation
3239 -- Here we have an acceptable interpretation for the context
3241 -- Propagate type information and normalize tree for various
3242 -- predefined operations. If the context only imposes a class of
3243 -- types, rather than a specific type, propagate the actual type
3244 -- downward.
3250 Typ = Any_Discrete
3251 then
3254 -- Any_Fixed is legal in a real context only if a specific fixed-
3255 -- point type is imposed. If Norman Cohen can be confused by this,
3256 -- it deserves a separate message.
3260 then
3267 -- A user-defined operator is transformed into a function call at
3268 -- this point, so that further processing knows that operators are
3269 -- really operators (i.e. are predefined operators). User-defined
3270 -- operators that are intrinsic are just renamings of the predefined
3271 -- ones, and need not be turned into calls either, but if they rename
3272 -- a different operator, we must transform the node accordingly.
3273 -- Instantiations of Unchecked_Conversion are intrinsic but are
3274 -- treated as functions, even if given an operator designator.
3279 then
3284 and then
3286 N_Subprogram_Renaming_Declaration
3287 then
3290 -- If the node is rewritten, it will be fully resolved in
3291 -- Rewrite_Renamed_Operator.
3300 when N_Aggregate =>
3301 Resolve_Aggregate (N, Ctx_Type);
3303 when N_Allocator =>
3304 Resolve_Allocator (N, Ctx_Type);
3306 when N_Short_Circuit =>
3307 Resolve_Short_Circuit (N, Ctx_Type);
3309 when N_Attribute_Reference =>
3310 Resolve_Attribute (N, Ctx_Type);
3312 when N_Case_Expression =>
3313 Resolve_Case_Expression (N, Ctx_Type);
3315 when N_Character_Literal =>
3316 Resolve_Character_Literal (N, Ctx_Type);
3318 when N_Delta_Aggregate =>
3319 Resolve_Delta_Aggregate (N, Ctx_Type);
3321 when N_Expanded_Name =>
3322 Resolve_Entity_Name (N, Ctx_Type);
3324 when N_Explicit_Dereference =>
3325 Resolve_Explicit_Dereference (N, Ctx_Type);
3327 when N_Expression_With_Actions =>
3328 Resolve_Expression_With_Actions (N, Ctx_Type);
3330 when N_Extension_Aggregate =>
3331 Resolve_Extension_Aggregate (N, Ctx_Type);
3333 when N_Function_Call =>
3334 Resolve_Call (N, Ctx_Type);
3336 when N_Identifier =>
3337 Resolve_Entity_Name (N, Ctx_Type);
3339 when N_If_Expression =>
3340 Resolve_If_Expression (N, Ctx_Type);
3342 when N_Indexed_Component =>
3343 Resolve_Indexed_Component (N, Ctx_Type);
3345 when N_Integer_Literal =>
3346 Resolve_Integer_Literal (N, Ctx_Type);
3348 when N_Membership_Test =>
3349 Resolve_Membership_Op (N, Ctx_Type);
3351 when N_Null =>
3352 Resolve_Null (N, Ctx_Type);
3354 when N_Op_And
3355 | N_Op_Or
3356 | N_Op_Xor
3357 =>
3358 Resolve_Logical_Op (N, Ctx_Type);
3360 when N_Op_Eq
3361 | N_Op_Ne
3362 =>
3363 Resolve_Equality_Op (N, Ctx_Type);
3365 when N_Op_Ge
3366 | N_Op_Gt
3367 | N_Op_Le
3368 | N_Op_Lt
3369 =>
3370 Resolve_Comparison_Op (N, Ctx_Type);
3372 when N_Op_Not =>
3373 Resolve_Op_Not (N, Ctx_Type);
3375 when N_Op_Add
3376 | N_Op_Divide
3377 | N_Op_Mod
3378 | N_Op_Multiply
3379 | N_Op_Rem
3380 | N_Op_Subtract
3381 =>
3382 Resolve_Arithmetic_Op (N, Ctx_Type);
3384 when N_Op_Concat =>
3385 Resolve_Op_Concat (N, Ctx_Type);
3387 when N_Op_Expon =>
3388 Resolve_Op_Expon (N, Ctx_Type);
3390 when N_Op_Abs
3391 | N_Op_Minus
3392 | N_Op_Plus
3393 =>
3394 Resolve_Unary_Op (N, Ctx_Type);
3396 when N_Op_Shift =>
3397 Resolve_Shift (N, Ctx_Type);
3399 when N_Procedure_Call_Statement =>
3400 Resolve_Call (N, Ctx_Type);
3402 when N_Operator_Symbol =>
3403 Resolve_Operator_Symbol (N, Ctx_Type);
3405 when N_Qualified_Expression =>
3406 Resolve_Qualified_Expression (N, Ctx_Type);
3408 -- Why is the following null, needs a comment ???
3410 when N_Quantified_Expression =>
3411 null;
3413 when N_Raise_Expression =>
3414 Resolve_Raise_Expression (N, Ctx_Type);
3416 when N_Raise_xxx_Error =>
3417 Set_Etype (N, Ctx_Type);
3419 when N_Range =>
3420 Resolve_Range (N, Ctx_Type);
3422 when N_Real_Literal =>
3423 Resolve_Real_Literal (N, Ctx_Type);
3425 when N_Reference =>
3426 Resolve_Reference (N, Ctx_Type);
3428 when N_Selected_Component =>
3429 Resolve_Selected_Component (N, Ctx_Type);
3431 when N_Slice =>
3432 Resolve_Slice (N, Ctx_Type);
3434 when N_String_Literal =>
3435 Resolve_String_Literal (N, Ctx_Type);
3437 when N_Target_Name =>
3438 Resolve_Target_Name (N, Ctx_Type);
3440 when N_Type_Conversion =>
3441 Resolve_Type_Conversion (N, Ctx_Type);
3443 when N_Unchecked_Expression =>
3444 Resolve_Unchecked_Expression (N, Ctx_Type);
3446 when N_Unchecked_Type_Conversion =>
3447 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3448 end case;
3450 -- Mark relevant use-type and use-package clauses as effective using
3451 -- the original node because constant folding may have occurred and
3452 -- removed references that need to be examined.
3454 if Nkind (Original_Node (N)) in N_Op then
3455 Mark_Use_Clauses (Original_Node (N));
3456 end if;
3458 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3459 -- expression of an anonymous access type that occurs in the context
3460 -- of a named general access type, except when the expression is that
3461 -- of a membership test. This ensures proper legality checking in
3462 -- terms of allowed conversions (expressions that would be illegal to
3463 -- convert implicitly are allowed in membership tests).
3465 if Ada_Version >= Ada_2012
3466 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3467 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3468 and then Nkind (Parent (N)) not in N_Membership_Test
3469 then
3470 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3471 Analyze_And_Resolve (N, Ctx_Type);
3472 end if;
3474 -- If the subexpression was replaced by a non-subexpression, then
3475 -- all we do is to expand it. The only legitimate case we know of
3476 -- is converting procedure call statement to entry call statements,
3477 -- but there may be others, so we are making this test general.
3479 if Nkind (N) not in N_Subexpr then
3480 Debug_A_Exit ("resolving ", N, " (done)");
3481 Expand (N);
3482 return;
3483 end if;
3485 -- The expression is definitely NOT overloaded at this point, so
3486 -- we reset the Is_Overloaded flag to avoid any confusion when
3487 -- reanalyzing the node.
3489 Set_Is_Overloaded (N, False);
3491 -- Freeze expression type, entity if it is a name, and designated
3492 -- type if it is an allocator (RM 13.14(10,11,13)).
3494 -- Now that the resolution of the type of the node is complete, and
3495 -- we did not detect an error, we can expand this node. We skip the
3496 -- expand call if we are in a default expression, see section
3497 -- "Handling of Default Expressions" in Sem spec.
3499 Debug_A_Exit ("resolving ", N, " (done)");
3501 -- We unconditionally freeze the expression, even if we are in
3502 -- default expression mode (the Freeze_Expression routine tests this
3503 -- flag and only freezes static types if it is set).
3505 -- Ada 2012 (AI05-177): The declaration of an expression function
3506 -- does not cause freezing, but we never reach here in that case.
3507 -- Here we are resolving the corresponding expanded body, so we do
3508 -- need to perform normal freezing.
3510 -- As elsewhere we do not emit freeze node within a generic.
3512 if not Inside_A_Generic then
3513 Freeze_Expression (N);
3514 end if;
3516 -- Now we can do the expansion
3518 Expand (N);
3519 end if;
3520 end Resolve;
3522 -------------
3523 -- Resolve --
3524 -------------
3526 -- Version with check(s) suppressed
3528 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3529 begin
3530 if Suppress = All_Checks then
3531 declare
3532 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3533 begin
3534 Scope_Suppress.Suppress := (others => True);
3535 Resolve (N, Typ);
3536 Scope_Suppress.Suppress := Sva;
3537 end;
3539 else
3540 declare
3541 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3542 begin
3543 Scope_Suppress.Suppress (Suppress) := True;
3544 Resolve (N, Typ);
3545 Scope_Suppress.Suppress (Suppress) := Svg;
3546 end;
3547 end if;
3548 end Resolve;
3550 -------------
3551 -- Resolve --
3552 -------------
3554 -- Version with implicit type
3556 procedure Resolve (N : Node_Id) is
3557 begin
3558 Resolve (N, Etype (N));
3559 end Resolve;
3561 ---------------------
3562 -- Resolve_Actuals --
3563 ---------------------
3565 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3566 Loc : constant Source_Ptr := Sloc (N);
3567 A : Node_Id;
3568 A_Typ : Entity_Id := Empty; -- init to avoid warning
3569 F : Entity_Id;
3570 F_Typ : Entity_Id;
3571 Prev : Node_Id := Empty;
3572 Orig_A : Node_Id;
3573 Real_F : Entity_Id := Empty; -- init to avoid warning
3575 Real_Subp : Entity_Id;
3576 -- If the subprogram being called is an inherited operation for
3577 -- a formal derived type in an instance, Real_Subp is the subprogram
3578 -- that will be called. It may have different formal names than the
3579 -- operation of the formal in the generic, so after actual is resolved
3580 -- the name of the actual in a named association must carry the name
3581 -- of the actual of the subprogram being called.
3583 procedure Check_Aliased_Parameter;
3584 -- Check rules on aliased parameters and related accessibility rules
3585 -- in (RM 3.10.2 (10.2-10.4)).
3587 procedure Check_Argument_Order;
3588 -- Performs a check for the case where the actuals are all simple
3589 -- identifiers that correspond to the formal names, but in the wrong
3590 -- order, which is considered suspicious and cause for a warning.
3592 procedure Check_Prefixed_Call;
3593 -- If the original node is an overloaded call in prefix notation,
3595 -- Try_Object_Operation has already verified that there is a valid
3596 -- interpretation, but the form of the actual can only be determined
3597 -- once the primitive operation is identified.
3600 -- Emit an error concerning the illegal usage of an effectively volatile
3601 -- object for reading in interfering context (SPARK RM 7.1.3(10)).
3604 -- If the actual is missing in a call, insert in the actuals list
3605 -- an instance of the default expression. The insertion is always
3606 -- a named association.
3609 -- Check whether T1 and T2, or their full views, are derived from a
3610 -- common type. Used to enforce the restrictions on array conversions
3611 -- of AI95-00246.
3614 -- Predicate to determine whether an actual that is a concatenation
3615 -- will be evaluated statically and does not need a transient scope.
3616 -- This must be determined before the actual is resolved and expanded
3617 -- because if needed the transient scope must be introduced earlier.
3619 -----------------------------
3620 -- Check_Aliased_Parameter --
3621 -----------------------------
3626 begin
3634 else
3641 -- In a generic body assume the worst for generic formals:
3642 -- they can have a constrained partial view (AI05-041).
3646 and then not Object_Type_Has_Constrained_Partial_View
3648 then
3651 else
3656 else
3668 then
3676 then
3677 Error_Msg_N
3683 --------------------------
3684 -- Check_Argument_Order --
3685 --------------------------
3688 begin
3689 -- Nothing to do if no parameters, or original node is neither a
3690 -- function call nor a procedure call statement (happens in the
3691 -- operator-transformed-to-function call case), or the call is to an
3692 -- operator symbol (which is usually in infix form), or the call does
3693 -- not come from source, or this warning is off.
3695 if not Warn_On_Parameter_Order
3701 N_Defining_Operator_Symbol)
3703 then
3707 declare
3710 begin
3711 -- Nothing to do if only one parameter
3717 -- Here if at least two arguments
3719 declare
3725 -- Set True if an out of order case is found
3727 begin
3728 -- Collect identifier names of actuals, fail if any actual is
3729 -- not a simple identifier, and record max length of name.
3735 else
3741 -- If we got this far, all actuals are identifiers and the list
3742 -- of their names is stored in the Actuals array.
3747 -- If we ran out of formals, that's odd, probably an error
3748 -- which will be detected elsewhere, but abandon the search.
3754 -- If name matches and is in order OK
3759 else
3760 -- If no match, see if it is elsewhere in list and if so
3761 -- flag potential wrong order if type is compatible.
3765 and then
3767 then
3773 -- No match
3781 -- If Formals left over, also probably an error, skip warning
3787 -- Here we give the warning if something was out of order
3790 Error_Msg_N
3797 -------------------------
3798 -- Check_Prefixed_Call --
3799 -------------------------
3808 begin
3809 -- Check whether the call is a prefixed call, with or without
3810 -- additional actuals.
3813 or else
3819 then
3822 then
3823 -- Introduce dereference on object in prefix
3825 New_A :=
3833 then
3834 -- Introduce an implicit 'Access in prefix
3837 Error_Msg_NE
3853 ---------------------------------------
3854 -- Flag_Effectively_Volatile_Objects --
3855 ---------------------------------------
3859 -- Determine whether arbitrary node N denotes an effectively volatile
3860 -- object for reading and if it does, emit an error.
3862 -----------------
3863 -- Flag_Object --
3864 -----------------
3869 begin
3871 -- Do not consider nested function calls because they have
3872 -- already been processed during their own resolution.
3880 -- Identifiers of components and discriminants are not names
3881 -- in the sense of Ada RM 4.1. They can only occur as a
3882 -- selector_name in selected_component or as a choice in
3883 -- component_association.
3889 and then
3893 then
3894 Error_Msg_N
3908 -- Start of processing for Flag_Effectively_Volatile_Objects
3910 begin
3914 --------------------
3915 -- Insert_Default --
3916 --------------------
3922 begin
3923 -- Missing argument in call, nothing to insert
3928 else
3929 -- Note that we do a full New_Copy_Tree, so that any associated
3930 -- Itypes are properly copied. This may not be needed any more,
3931 -- but it does no harm as a safety measure. Defaults of a generic
3932 -- formal may be out of bounds of the corresponding actual (see
3933 -- cc1311b) and an additional check may be required.
3935 Actval :=
3936 New_Copy_Tree
3941 -- Propagate dimension information, if any.
3947 then
3953 then
3956 then
3957 -- If default is a real literal, do not introduce a
3958 -- conversion whose effect may depend on the run-time
3959 -- size of universal real.
3963 else
3974 -- Resolve aggregates with their base type, to avoid scope
3975 -- anomalies: the subtype was first built in the subprogram
3976 -- declaration, and the current call may be nested.
3980 else
3984 else
3987 -- See note above concerning aggregates
3991 then
3994 -- Resolve entities with their own type, which may differ from
3995 -- the type of a reference in a generic context (the view
3996 -- swapping mechanism did not anticipate the re-analysis of
3997 -- default values in calls).
4002 else
4007 -- If default is a tag indeterminate function call, propagate tag
4008 -- to obtain proper dispatching.
4012 then
4017 -- If the default expression raises constraint error, then just
4018 -- silently replace it with an N_Raise_Constraint_Error node, since
4019 -- we already gave the warning on the subprogram spec. If node is
4020 -- already a Raise_Constraint_Error leave as is, to prevent loops in
4021 -- the warnings removal machinery.
4025 then
4034 Assoc :=
4039 -- Case of insertion is first named actual
4043 then
4050 else
4054 else
4058 -- Case of insertion is not first named actual
4060 else
4061 Set_Next_Named_Actual
4073 -------------------
4074 -- Same_Ancestor --
4075 -------------------
4081 begin
4084 then
4090 then
4097 --------------------------
4098 -- Static_Concatenation --
4099 --------------------------
4102 begin
4109 -- Concatenation is static when both operands are static and
4110 -- the concatenation operator is a predefined one.
4113 and then
4115 and then
4120 declare
4122 begin
4125 and then
4129 else
4135 -- Start of processing for Resolve_Actuals
4137 begin
4138 Check_Argument_Order;
4142 and then In_Instance
4145 then
4147 else
4152 Check_Prefixed_Call;
4166 -- If we have an error in any formal or actual, indicated by a type
4167 -- of Any_Type, then abandon resolution attempt, and set result type
4168 -- to Any_Type.
4175 -- For the peculiar case of a user-defined comparison or equality
4176 -- operator that does not return a boolean type, the operands may
4177 -- have been ambiguous for the predefined operator and, therefore,
4178 -- marked with Any_Type. Since the operation has been resolved to
4179 -- the user-defined operator, that is irrelevant, so reset Etype.
4183 then
4186 -- Also skip this if the actual is a Raise_Expression, whose type
4187 -- is imposed from context.
4192 else
4198 -- Case where actual is present
4200 -- If the actual is an entity, generate a reference to it now. We
4201 -- do this before the actual is resolved, because a formal of some
4202 -- protected subprogram, or a task discriminant, will be rewritten
4203 -- during expansion, and the source entity reference may be lost.
4208 then
4209 -- Annotate the tree by creating a variable reference marker when
4210 -- the actual denotes a variable reference, in case the reference
4211 -- is folded or optimized away. The variable reference marker is
4212 -- automatically saved for later examination by the ABE Processing
4213 -- phase. The status of the reference is set as follows:
4215 -- status mode
4216 -- read IN, IN OUT
4217 -- write IN OUT, OUT
4219 if Needs_Variable_Reference_Marker
4222 then
4223 Build_Variable_Reference_Marker
4234 then
4241 -- RM 6.4.1(12): For an out parameter that is passed by
4242 -- copy, the formal parameter object is created, and:
4244 -- * For an access type, the formal parameter is initialized
4245 -- from the value of the actual, without checking that the
4246 -- value satisfies any constraint, any predicate, or any
4247 -- exclusion of the null value.
4249 -- * For a scalar type that has the Default_Value aspect
4250 -- specified, the formal parameter is initialized from the
4251 -- value of the actual, without checking that the value
4252 -- satisfies any constraint or any predicate.
4253 -- I do not understand why this case is included??? this is
4254 -- not a case where an OUT parameter is treated as IN OUT.
4256 -- * For a composite type with discriminants or that has
4257 -- implicit initial values for any subcomponents, the
4258 -- behavior is as for an in out parameter passed by copy.
4260 -- Hence for these cases we generate the read reference now
4261 -- (the write reference will be generated later by
4262 -- Note_Possible_Modification).
4265 and then
4267 or else
4269 and then
4271 or else
4274 or else Is_Partially_Initialized_Type
4276 then
4286 then
4287 -- If style checking mode on, check match of formal name
4295 -- If the formal is Out or In_Out, do not resolve and expand the
4296 -- conversion, because it is subsequently expanded into explicit
4297 -- temporaries and assignments. However, the object of the
4298 -- conversion can be resolved. An exception is the case of tagged
4299 -- type conversion with a class-wide actual. In that case we want
4300 -- the tag check to occur and no temporary will be needed (no
4301 -- representation change can occur) and the parameter is passed by
4302 -- reference, so we go ahead and resolve the type conversion.
4303 -- Another exception is the case of reference to component or
4304 -- subcomponent of a bit-packed array, in which case we want to
4305 -- defer expansion to the point the in and out assignments are
4306 -- performed.
4312 then
4313 declare
4316 begin
4317 -- Check RM 4.6 (24.2/2)
4321 then
4322 -- In a view conversion, the conversion must be legal in
4323 -- both directions, and thus both component types must be
4324 -- aliased, or neither (4.6 (8)).
4326 -- Check RM 4.6 (24.8/2)
4330 then
4331 -- This normally illegal conversion is legal in an
4332 -- expanded instance body because of RM 12.3(11).
4333 -- At runtime, conversion must create a new object.
4336 Error_Msg_N
4341 -- Check RM 4.6 (24/3)
4344 -- Check view conv between unrelated by ref array
4345 -- types.
4349 then
4350 Error_Msg_N
4354 -- In Ada 2005 mode, check view conversion component
4355 -- type cannot be private, tagged, or volatile. Note
4356 -- that we only apply this to source conversions. The
4357 -- generated code can contain conversions which are
4358 -- not subject to this test, and we cannot extract the
4359 -- component type in such cases since it is not
4360 -- present.
4364 then
4365 declare
4368 begin
4373 then
4374 Error_Msg_N
4384 -- AI12-0074 & AI12-0377
4385 -- Check 6.4.1: If the mode is out, the actual parameter is
4386 -- a view conversion, and the type of the formal parameter
4387 -- is a scalar type, then either:
4388 -- - the target and operand type both do not have the
4389 -- Default_Value aspect specified; or
4390 -- - the target and operand type both have the
4391 -- Default_Value aspect specified, and there shall exist
4392 -- a type (other than a root numeric type) that is an
4393 -- ancestor of both the target type and the operand
4394 -- type.
4398 then
4401 then
4402 Error_Msg_N
4407 then
4408 Error_Msg_N
4415 -- Resolve expression if conversion is all OK
4420 then
4424 -- If the actual is a function call that returns a limited
4425 -- unconstrained object that needs finalization, create a
4426 -- transient scope for it, so that it can receive the proper
4427 -- finalization list.
4429 elsif Expander_Active
4435 then
4439 -- A small optimization: if one of the actuals is a concatenation
4440 -- create a block around a procedure call to recover stack space.
4441 -- This alleviates stack usage when several procedure calls in
4442 -- the same statement list use concatenation. We do not perform
4443 -- this wrapping for code statements, where the argument is a
4444 -- static string, and we want to preserve warnings involving
4445 -- sequences of such statements.
4447 elsif Expander_Active
4453 then
4457 else
4461 and then
4464 then
4465 Error_Msg_N
4478 -- (Ada 2005: AI-251): If the actual is an allocator whose
4479 -- directly designated type is a class-wide interface, we build
4480 -- an anonymous access type to use it as the type of the
4481 -- allocator. Later, when the subprogram call is expanded, if
4482 -- the interface has a secondary dispatch table the expander
4483 -- will add a type conversion to force the correct displacement
4484 -- of the pointer.
4487 declare
4491 begin
4492 -- Displace the pointer to the object to reference its
4493 -- secondary dispatch table.
4497 then
4503 -- Ada 2005, AI-162:If the actual is an allocator, the
4504 -- innermost enclosing statement is the master of the
4505 -- created object. This needs to be done with expansion
4506 -- enabled only, otherwise the transient scope will not
4507 -- be removed in the expansion of the wrapped construct.
4509 if Expander_Active
4512 then
4513 Establish_Transient_Scope
4523 -- (Ada 2005): The call may be to a primitive operation of a
4524 -- tagged synchronized type, declared outside of the type. In
4525 -- this case the controlling actual must be converted to its
4526 -- corresponding record type, which is the formal type. The
4527 -- actual may be a subtype, either because of a constraint or
4528 -- because it is a generic actual, so use base type to locate
4529 -- concurrent type.
4536 then
4537 -- If the actual is overloaded, look for an interpretation
4538 -- that has a synchronized type.
4543 else
4544 declare
4548 begin
4553 then
4563 declare
4566 begin
4569 else
4573 -- Tagged synchronized type (case 1): the actual is a
4574 -- concurrent type.
4578 then
4580 Unchecked_Convert_To
4584 -- Tagged synchronized type (case 2): the formal is a
4585 -- concurrent type.
4588 and then Present
4593 then
4596 -- Common case
4598 else
4603 -- Not a synchronized operation
4605 else
4613 -- An actual cannot be an untagged formal incomplete type
4618 then
4619 Error_Msg_N
4623 -- has warnings suppressed, then we reset Never_Set_In_Source for
4624 -- the calling entity. The reason for this is to catch cases like
4625 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4626 -- uses trickery to modify an IN parameter.
4633 then
4637 -- Perform error checks for IN and IN OUT parameters
4641 -- Check unset reference. For scalar parameters, it is clearly
4642 -- wrong to pass an uninitialized value as either an IN or
4643 -- IN-OUT parameter. For composites, it is also clearly an
4644 -- error to pass a completely uninitialized value as an IN
4645 -- parameter, but the case of IN OUT is trickier. We prefer
4646 -- not to give a warning here. For example, suppose there is
4647 -- a routine that sets some component of a record to False.
4648 -- It is perfectly reasonable to make this IN-OUT and allow
4649 -- either initialized or uninitialized records to be passed
4650 -- in this case.
4652 -- For partially initialized composite values, we also avoid
4653 -- warnings, since it is quite likely that we are passing a
4654 -- partially initialized value and only the initialized fields
4655 -- will in fact be read in the subprogram.
4660 then
4664 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4665 -- actual to a nested call, since this constitutes a reading of
4666 -- the parameter, which is not allowed.
4671 then
4676 -- In -gnatd.q mode, forget that a given array is constant when
4677 -- it is passed as an IN parameter to a foreign-convention
4678 -- subprogram. This is in case the subprogram evilly modifies the
4679 -- object. Of course, correct code would use IN OUT.
4681 if Debug_Flag_Dot_Q
4687 then
4691 -- Case of OUT or IN OUT parameter
4695 -- For an Out parameter, check for useless assignment. Note
4696 -- that we can't set Last_Assignment this early, because we may
4697 -- kill current values in Resolve_Call, and that call would
4698 -- clobber the Last_Assignment field.
4700 -- Note: call Warn_On_Useless_Assignment before doing the check
4701 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4702 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4703 -- reflects the last assignment, not this one.
4710 then
4715 -- Validate the form of the actual. Note that the call to
4716 -- Is_OK_Variable_For_Out_Formal generates the required
4717 -- reference in this case.
4719 -- A call to an initialization procedure for an aggregate
4720 -- component may initialize a nested component of a constant
4721 -- designated object. In this context the object is variable.
4725 then
4731 then
4732 Error_Msg_N
4737 Error_Msg_N
4744 -- What's the following about???
4748 else
4749 Kill_All_Checks;
4758 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4762 -- Apply predicate tests except in certain special cases. Note
4763 -- that it might be more consistent to apply these only when
4764 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4765 -- for the outbound predicate tests ??? In any case indicate
4766 -- the function being called, for better warnings if the call
4767 -- leads to an infinite recursion.
4773 -- Apply required constraint checks
4786 then
4789 -- For view conversions of a discriminated object, apply
4790 -- check to object itself, the conversion alreay has the
4791 -- proper type.
4795 then
4802 then
4808 then
4811 else
4815 -- Ada 2005 (AI-231): Note that the controlling parameter case
4816 -- already existed in Ada 95, which is partially checked
4817 -- elsewhere (see Checks), and we don't want the warning
4818 -- message to differ.
4823 then
4825 Apply_Compile_Time_Constraint_Error
4831 Apply_Compile_Time_Constraint_Error
4840 -- Checks for OUT parameters and IN OUT parameters
4844 -- If there is a type conversion, make sure the return value
4845 -- meets the constraints of the variable before the conversion.
4850 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4851 -- which would prevent the check from being generated.
4852 -- This is for Starlet only though, so long obsolete.
4857 then
4859 else
4860 Apply_Scalar_Range_Check
4864 -- In addition the return value must meet the constraints
4865 -- of the object type (see the comment below).
4869 else
4870 Apply_Range_Check
4874 -- If no conversion, apply scalar range checks and length check
4875 -- based on the subtype of the actual (NOT that of the formal).
4876 -- This indicates that the check takes place on return from the
4877 -- call. During expansion the required constraint checks are
4878 -- inserted. In GNATprove mode, in the absence of expansion,
4879 -- the flag indicates that the returned value is valid.
4881 else
4887 then
4890 else
4895 -- Note: we do not apply the predicate checks for the case of
4896 -- OUT and IN OUT parameters. They are instead applied in the
4897 -- Expand_Actuals routine in Exp_Ch6.
4900 -- If the formal is of an unconstrained array subtype with fixed
4901 -- lower bound, then sliding to that bound may be needed.
4907 -- An actual associated with an access parameter is implicitly
4908 -- converted to the anonymous access type of the formal and must
4909 -- satisfy the legality checks for access conversions.
4913 Error_Msg_N
4917 -- If the actual is an access selected component of a variable,
4918 -- the call may modify its designated object. It is reasonable
4919 -- to treat this as a potential modification of the enclosing
4920 -- record, to prevent spurious warnings that it should be
4921 -- declared as a constant, because intuitively programmers
4922 -- regard the designated subcomponent as part of the record.
4927 then
4932 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
4936 then
4939 then
4940 Error_Msg_NE
4943 Error_Msg_N
4948 then
4949 Error_Msg_NE
4952 Error_Msg_N
4957 then
4958 Error_Msg_NE
4961 Error_Msg_N
4965 -- Check for nonatomic subcomponent of a full access object
4966 -- in Ada 2022 (RM C.6 (12)).
4971 then
4972 Error_Msg_N
4975 Error_Msg_NE
4981 -- Check that subprograms don't have improper controlling
4982 -- arguments (RM 3.9.2 (9)).
4984 -- A primitive operation may have an access parameter of an
4985 -- incomplete tagged type, but a dispatching call is illegal
4986 -- if the type is still incomplete.
4992 declare
4994 begin
4998 then
4999 Error_Msg_NE
5010 -- Apply legality rule 3.9.2 (9/1)
5012 -- Skip this check on helpers and indirect-call wrappers built to
5013 -- support class-wide preconditions.
5018 and then not In_Instance
5021 then
5026 Error_Msg_NE
5030 -- Apply the checks described in 3.10.2(27): if the context is a
5031 -- specific access-to-object, the actual cannot be class-wide.
5032 -- Use base type to exclude access_to_subprogram cases.
5039 and then
5044 -- Disable these checks for call to imported C++ subprograms
5046 and then not
5050 then
5051 Error_Msg_N
5056 Error_Msg_NE
5061 Check_Aliased_Parameter;
5065 -- If it is a named association, treat the selector_name as a
5066 -- proper identifier, and mark the corresponding entity.
5070 -- Ignore reference in SPARK mode, as it refers to an entity not
5071 -- in scope at the point of reference, so the reference should
5072 -- be ignored for computing effects of subprograms.
5074 and then not GNATprove_Mode
5075 then
5076 -- If subprogram is overridden, use name of formal that
5077 -- is being called.
5083 else
5097 -- The following checks are only relevant when SPARK_Mode is on as
5098 -- they are not standard Ada legality rule. Internally generated
5099 -- temporaries are ignored.
5103 -- Inspect the expression and flag each effectively volatile
5104 -- object for reading as illegal because it appears within
5105 -- an interfering context. Note that this is usually done
5106 -- in Resolve_Entity_Name, but when the effectively volatile
5107 -- object for reading appears as an actual in a call, the call
5108 -- must be resolved first.
5113 -- A formal parameter of a specific tagged type whose related
5114 -- subprogram is subject to pragma Extensions_Visible with value
5115 -- "False" cannot act as an actual in a subprogram with value
5116 -- "True" (SPARK RM 6.1.7(3)).
5118 -- No check needed for helpers and indirect-call wrappers built to
5119 -- support class-wide preconditions.
5123 Extensions_Visible_True
5125 then
5126 Error_Msg_N
5129 Error_Msg_NE
5133 -- The actual parameter of a Ghost subprogram whose formal is of
5134 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5142 then
5143 Error_Msg_NE
5149 else
5154 -- (AI12-0397): The target of a subprogram call that occurs within
5155 -- the expression of an Default_Initial_Condition aspect and has
5156 -- an actual that is the current instance of the type must be
5157 -- either a primitive of the type or a class-wide subprogram,
5158 -- because the type of the current instance in such an aspect is
5159 -- considered to be a notional formal derived type whose only
5160 -- operations correspond to the primitives of the enclosing type.
5161 -- Nonprimitives can be called, but the current instance must be
5162 -- converted rather than passed directly. Note that a current
5163 -- instance of a type with DIC will occur as a reference to an
5164 -- in-mode formal of an enclosing DIC procedure or partial DIC
5165 -- procedure. (It seems that this check should perhaps also apply
5166 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5167 -- aspects???)
5175 -- We check Comes_From_Source to exclude inherited primitives
5176 -- from being flagged, because such subprograms turn out to not
5177 -- always have the Is_Primitive flag set. ???
5183 then
5184 Error_Msg_NE
5191 -- Case where actual is not present
5193 else
5194 Insert_Default;
5205 -----------------------
5206 -- Resolve_Allocator --
5207 -----------------------
5219 procedure Check_Allocator_Discrim_Accessibility
5222 -- Check that accessibility level associated with an access discriminant
5223 -- initialized in an allocator by the expression Disc_Exp is not deeper
5224 -- than the level of the allocator type Alloc_Typ. An error message is
5225 -- issued if this condition is violated. Specialized checks are done for
5226 -- the cases of a constraint expression which is an access attribute or
5227 -- an access discriminant.
5229 procedure Check_Allocator_Discrim_Accessibility_Exprs
5232 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5233 -- across all expressions within a given conditional expression.
5236 -- If the allocator is an actual in a call, it is allowed to be class-
5237 -- wide when the context is not because it is a controlling actual.
5239 -------------------------------------------
5240 -- Check_Allocator_Discrim_Accessibility --
5241 -------------------------------------------
5243 procedure Check_Allocator_Discrim_Accessibility
5246 is
5247 begin
5250 then
5251 Error_Msg_N
5254 -- When the expression is an Access attribute the level of the prefix
5255 -- object must not be deeper than that of the allocator's type.
5259 Attribute_Access
5260 and then Static_Accessibility_Level
5263 then
5264 Error_Msg_N
5266 Disc_Exp);
5268 -- When the expression is an access discriminant the check is against
5269 -- the level of the prefix object.
5273 and then Static_Accessibility_Level
5276 then
5277 Error_Msg_N
5279 Disc_Exp);
5281 -- All other cases are legal
5283 else
5288 -------------------------------------------------
5289 -- Check_Allocator_Discrim_Accessibility_Exprs --
5290 -------------------------------------------------
5292 procedure Check_Allocator_Discrim_Accessibility_Exprs
5295 is
5299 begin
5300 -- When conditional expressions are constant folded we know at
5301 -- compile time which expression to check - so don't bother with
5302 -- the rest of the cases.
5307 -- Non-constant-folded if expressions
5310 -- Check both expressions if they are still present in the face
5311 -- of expansion.
5318 Check_Allocator_Discrim_Accessibility_Exprs
5323 -- Non-constant-folded case expressions
5326 -- Check all alternatives
5330 Check_Allocator_Discrim_Accessibility_Exprs
5336 -- Base case, check the accessibility of the original node of the
5337 -- expression.
5339 else
5344 ----------------------------
5345 -- In_Dispatching_Context --
5346 ----------------------------
5351 begin
5357 -- Start of processing for Resolve_Allocator
5359 begin
5360 -- Replace general access with specific type
5370 -- For qualified expression, resolve the expression using the given
5371 -- subtype (nothing to do for type mark, subtype indication)
5376 and then not In_Dispatching_Context
5377 then
5378 Error_Msg_N
5382 -- Do a full resolution to apply constraint and predicate checks
5387 -- Allocators generated by the build-in-place expansion mechanism
5388 -- are explicitly marked as coming from source but do not need to be
5389 -- checked for limited initialization. To exclude this case, ensure
5390 -- that the parent of the allocator is a source node.
5391 -- The return statement constructed for an Expression_Function does
5392 -- not come from source but requires a limited check.
5396 and then
5398 or else
5402 and then not In_Instance_Body
5403 then
5406 Error_Msg_N
5409 else
5410 Error_Msg_N
5418 -- Calls to build-in-place functions are not currently supported in
5419 -- allocators for access types associated with a simple storage pool.
5420 -- Supporting such allocators may require passing additional implicit
5421 -- parameters to build-in-place functions (or a significant revision
5422 -- of the current b-i-p implementation to unify the handling for
5423 -- multiple kinds of storage pools). ???
5427 then
5428 declare
5431 begin
5433 and then
5434 Present (Get_Rep_Pragma
5436 then
5437 Error_Msg_N
5444 -- A special accessibility check is needed for allocators that
5445 -- constrain access discriminants. The level of the type of the
5446 -- expression used to constrain an access discriminant cannot be
5447 -- deeper than the type of the allocator (in contrast to access
5448 -- parameters, where the level of the actual can be arbitrary).
5450 -- We can't use Valid_Conversion to perform this check because in
5451 -- general the type of the allocator is unrelated to the type of
5452 -- the access discriminant.
5456 then
5463 then
5466 -- Get the first component expression of the aggregate
5476 else
5480 else
5486 Check_Allocator_Discrim_Accessibility_Exprs
5500 else
5505 else
5514 -- For a subtype mark or subtype indication, freeze the subtype
5516 else
5520 Error_Msg_N
5524 -- A special accessibility check is needed for allocators that
5525 -- constrain access discriminants. The level of the type of the
5526 -- expression used to constrain an access discriminant cannot be
5527 -- deeper than the type of the allocator (in contrast to access
5528 -- parameters, where the level of the actual can be arbitrary).
5529 -- We can't use Valid_Conversion to perform this check because
5530 -- in general the type of the allocator is unrelated to the type
5531 -- of the access discriminant.
5536 then
5546 else
5550 Check_Allocator_Discrim_Accessibility_Exprs
5561 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5562 -- check that the level of the type of the created object is not deeper
5563 -- than the level of the allocator's access type, since extensions can
5564 -- now occur at deeper levels than their ancestor types. This is a
5565 -- static accessibility level check; a run-time check is also needed in
5566 -- the case of an initialized allocator with a class-wide argument (see
5567 -- Expand_Allocator_Expression).
5571 then
5572 declare
5575 begin
5580 else
5586 then
5589 Error_Msg_N
5599 -- Do not apply Ada 2005 accessibility checks on a class-wide
5600 -- allocator if the type given in the allocator is a formal
5601 -- type or within a formal package. A run-time check will be
5602 -- performed in the instance.
5606 then
5607 Error_Msg_N
5615 -- Check for allocation from an empty storage pool. But do not complain
5616 -- if it's a return statement for a build-in-place function, because the
5617 -- allocator is there just in case the caller uses an allocator. If the
5618 -- caller does use an allocator, it will be caught at the call site.
5622 then
5625 -- If the context is an unchecked conversion, as may happen within an
5626 -- inlined subprogram, the allocator is being resolved with its own
5627 -- anonymous type. In that case, if the target type has a specific
5628 -- storage pool, it must be inherited explicitly by the allocator type.
5632 then
5633 Set_Associated_Storage_Pool
5641 -- Check that an allocator with task parts isn't for a nested access
5642 -- type when restriction No_Task_Hierarchy applies.
5646 then
5650 -- An illegal allocator may be rewritten as a raise Program_Error
5651 -- statement.
5655 -- Avoid coextension processing for an allocator that is the
5656 -- expansion of a build-in-place function call.
5660 N_Qualified_Expression
5662 N_Function_Call
5663 and then Is_Expanded_Build_In_Place_Call
5665 then
5668 else
5669 -- An anonymous access discriminant is the definition of a
5670 -- coextension.
5674 N_Discriminant_Specification
5675 then
5676 declare
5680 begin
5683 -- Ada 2012 AI05-0052: If the designated type of the
5684 -- allocator is limited, then the allocator shall not
5685 -- be used to define the value of an access discriminant
5686 -- unless the discriminated type is immutably limited.
5691 then
5692 Error_Msg_N
5695 N);
5699 -- Avoid marking an allocator as a dynamic coextension if it is
5700 -- within a static construct.
5705 -- Finalization and deallocation of coextensions utilizes an
5706 -- approximate implementation which does not directly adhere
5707 -- to the semantic rules. Warn on potential issues involving
5708 -- coextensions.
5711 Error_Msg_N
5714 else
5715 Error_Msg_N
5721 -- Cleanup for potential static coextensions
5723 else
5727 -- Anonymous access-to-controlled objects are not finalized on
5728 -- time because this involves run-time ownership and currently
5729 -- this property is not available. In rare cases the object may
5730 -- not be finalized at all. Warn on potential issues involving
5731 -- anonymous access-to-controlled objects.
5735 then
5736 Error_Msg_N
5746 -- Report a simple error: if the designated object is a local task,
5747 -- its body has not been seen yet, and its activation will fail an
5748 -- elaboration check.
5755 then
5761 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5762 -- type with a task component on a subpool. This action must raise
5763 -- Program_Error at runtime.
5769 then
5781 ---------------------------
5782 -- Resolve_Arithmetic_Op --
5783 ---------------------------
5785 -- Used for resolving all arithmetic operators except exponentiation
5796 -- We do the resolution using the base type, because intermediate values
5797 -- in expressions always are of the base type, not a subtype of it.
5800 -- Returns True if N is in a context that expects "any real type"
5803 -- Return True iff given type is Integer or universal real/integer
5806 -- Choose type of integer literal in fixed-point operation to conform
5807 -- to available fixed-point type. T is the type of the other operand,
5808 -- which is needed to determine the expected type of N.
5811 -- Set operand type to T if universal
5813 -------------------------------
5814 -- Expected_Type_Is_Any_Real --
5815 -------------------------------
5818 begin
5819 -- N is the expression after "delta" in a fixed_point_definition;
5820 -- see RM-3.5.9(6):
5823 | N_Decimal_Fixed_Point_Definition
5825 -- N is one of the bounds in a real_range_specification;
5826 -- see RM-3.5.7(5):
5828 | N_Real_Range_Specification
5830 -- N is the expression of a delta_constraint;
5831 -- see RM-J.3(3):
5833 | N_Delta_Constraint;
5836 -----------------------------
5837 -- Is_Integer_Or_Universal --
5838 -----------------------------
5845 begin
5850 else
5855 then
5866 ----------------------------
5867 -- Set_Mixed_Mode_Operand --
5868 ----------------------------
5874 begin
5877 -- A universal integer literal is resolved as standard integer
5878 -- except in the case of a fixed-point result, where we leave it
5879 -- as universal (to be handled by Exp_Fixd later on)
5883 else
5890 then
5891 -- A universal real can appear in a fixed-type context. We resolve
5892 -- the literal with that context, even though this might raise an
5893 -- exception prematurely (the other operand may be zero).
5900 then
5901 -- Integer arg in mixed-mode operation. Resolve with universal
5902 -- type, in case preference rule must be applied.
5908 -- If the operand is part of a fixed multiplication operation,
5909 -- a conversion will be applied to each operand, so resolve it
5910 -- with its own type.
5915 else
5916 -- Not a mixed-mode operation, resolve with context
5923 -- N may itself be a mixed-mode operation, so use context type
5930 then
5931 -- Must be (fixed * fixed) operation, operand must have one
5932 -- compatible interpretation.
5939 then
5940 -- C * F(X) in a fixed context, where C is a real literal or a
5941 -- fixed-point expression. F must have either a fixed type
5942 -- interpretation or an integer interpretation, but not both.
5949 else
5956 else
5964 -- Reanalyze the literal with the fixed type of the context. If
5965 -- context is Universal_Fixed, we are within a conversion, leave
5966 -- the literal as a universal real because there is no usable
5967 -- fixed type, and the target of the conversion plays no role in
5968 -- the resolution.
5970 declare
5974 begin
5977 else
5983 then
5985 else
5993 -- A universal real conditional expression can appear in a fixed-type
5994 -- context and must be resolved with that context to facilitate the
5995 -- code generation in the back end. However, If the context is
5996 -- Universal_fixed (i.e. as an operand of a multiplication/division
5997 -- involving a fixed-point operand) the conditional expression must
5998 -- resolve to a unique visible fixed_point type, normally Duration.
6003 then
6007 else
6011 else
6016 ----------------------
6017 -- Set_Operand_Type --
6018 ----------------------
6021 begin
6027 -- Start of processing for Resolve_Arithmetic_Op
6029 begin
6034 then
6038 -- Special-case for mixed-mode universal expressions or fixed point type
6039 -- operation: each argument is resolved separately. The same treatment
6040 -- is required if one of the operands of a fixed point operation is
6041 -- universal real, since in this case we don't do a conversion to a
6042 -- specific fixed-point type (instead the expander handles the case).
6044 -- Set the type of the node to its universal interpretation because
6045 -- legality checks on an exponentiation operand need the context.
6050 then
6061 or else
6064 then
6069 -- If context is a fixed type and one operand is integer, the other
6070 -- is resolved with the type of the context.
6075 then
6082 then
6086 -- If both operands are universal and the context is a floating
6087 -- point type, the operands are resolved to the type of the context.
6093 else
6098 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6099 -- multiplying operators from being used when the expected type is
6100 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6101 -- some cases where the expected type is actually Any_Real;
6102 -- Expected_Type_Is_Any_Real takes care of that case.
6106 then
6110 N_Type_Conversion | N_Unchecked_Type_Conversion
6111 then
6118 else
6122 N_Type_Conversion | N_Unchecked_Type_Conversion
6123 then
6124 Error_Msg_N
6129 -- The expected type is "any real type" in contexts like
6131 -- type T is delta <universal_fixed-expression> ...
6133 -- in which case we need to set the type to Universal_Real
6134 -- so that static expression evaluation will work properly.
6138 else
6148 then
6153 -- If no previous errors, this is only possible if one operand is
6154 -- overloaded and the context is universal. Resolve as such.
6159 else
6161 and then
6163 then
6167 -- If the context is Universal_Fixed and the operands are also
6168 -- universal fixed, this is an error, unless there is only one
6169 -- applicable fixed_point type (usually Duration).
6177 else
6182 else
6187 -- If one of the arguments was resolved to a non-universal type.
6188 -- label the result of the operation itself with the same type.
6189 -- Do the same for the universal argument, if any.
6201 -- Set overflow and division checking bit
6208 -- Give warning if explicit division by zero
6212 then
6218 or else
6221 then
6222 -- Specialize the warning message according to the operation.
6223 -- When SPARK_Mode is On, force a warning instead of an error
6224 -- in that case, as this likely corresponds to deactivated
6225 -- code. The following warnings are for the case
6230 -- For division, we have two cases, for float division
6231 -- of an unconstrained float type, on a machine where
6232 -- Machine_Overflows is false, we don't get an exception
6233 -- at run-time, but rather an infinity or Nan. The Nan
6234 -- case is pretty obscure, so just warn about infinities.
6238 and then not Machine_Overflows_On_Target
6239 then
6240 Error_Msg_N
6244 -- For all other cases, we get a Constraint_Error
6246 else
6247 Apply_Compile_Time_Constraint_Error
6254 Apply_Compile_Time_Constraint_Error
6260 Apply_Compile_Time_Constraint_Error
6265 -- Division by zero can only happen with division, rem,
6266 -- and mod operations.
6272 -- Otherwise just set the flag to check at run time
6274 else
6279 -- If Restriction No_Implicit_Conditionals is active, then it is
6280 -- violated if either operand can be negative for mod, or for rem
6281 -- if both operands can be negative.
6285 then
6286 declare
6293 -- Set if corresponding operand might be negative
6295 begin
6296 Determine_Range
6300 Determine_Range
6304 -- Check if we will be generating conditionals. There are two
6305 -- cases where that can happen, first for REM, the only case
6306 -- is largest negative integer mod -1, where the division can
6307 -- overflow, but we still have to give the right result. The
6308 -- front end generates a test for this annoying case. Here we
6309 -- just test if both operands can be negative (that's what the
6310 -- expander does, so we match its logic here).
6312 -- The second case is mod where either operand can be negative.
6313 -- In this case, the back end has to generate additional tests.
6316 or else
6318 then
6329 ------------------
6330 -- Resolve_Call --
6331 ------------------
6346 begin
6347 -- Preserve relevant elaboration-related attributes of the context which
6348 -- are no longer available or very expensive to recompute once analysis,
6349 -- resolution, and expansion are over.
6351 Mark_Elaboration_Attributes
6357 -- The context imposes a unique interpretation with type Typ on a
6358 -- procedure or function call. Find the entity of the subprogram that
6359 -- yields the expected type, and propagate the corresponding formal
6360 -- constraints on the actuals. The caller has established that an
6361 -- interpretation exists, and emitted an error if not unique.
6363 -- First deal with the case of a call to an access-to-subprogram,
6364 -- dereference made explicit in Analyze_Call.
6370 else
6371 -- Find the interpretation whose type (a subprogram type) has a
6372 -- return type that is compatible with the context. Analysis of
6373 -- the node has established that one exists.
6392 -- If the prefix is not an entity, then resolve it
6398 -- For an indirect call, we always invalidate checks, since we do not
6399 -- know whether the subprogram is local or global. Yes we could do
6400 -- better here, e.g. by knowing that there are no local subprograms,
6401 -- but it does not seem worth the effort. Similarly, we kill all
6402 -- knowledge of current constant values.
6404 Kill_Current_Values;
6406 -- If this is a procedure call which is really an entry call, do
6407 -- the conversion of the procedure call to an entry call. Protected
6408 -- operations use the same circuitry because the name in the call
6409 -- can be an arbitrary expression with special resolution rules.
6413 then
6420 -- Annotate the tree by creating a call marker in case the original
6421 -- call is transformed by expansion. The call marker is automatically
6422 -- saved for later examination by the ABE Processing phase.
6426 -- Kill checks and constant values, as above for indirect case
6427 -- Who knows what happens when another task is activated?
6429 Kill_Current_Values;
6432 -- Normal subprogram call with name established in Resolve
6438 -- Otherwise we must have the case of an overloaded call
6440 else
6443 -- Initialize Nam to prevent warning (we know it will be assigned
6444 -- in the loop below, but the compiler does not know that).
6460 -- Check that a call to Current_Task does not occur in an entry body
6463 declare
6466 begin
6468 loop
6471 -- Exclude calls that occur within the default of a formal
6472 -- parameter of the entry, since those are evaluated outside
6473 -- of the body.
6480 then
6483 Error_Msg_NE
6497 -- Check that a procedure call does not occur in the context of the
6498 -- entry call statement of a conditional or timed entry call. Note that
6499 -- the case of a call to a subprogram renaming of an entry will also be
6500 -- rejected. The test for N not being an N_Entry_Call_Statement is
6501 -- defensive, covering the possibility that the processing of entry
6502 -- calls might reach this point due to later modifications of the code
6503 -- above.
6508 then
6512 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6513 -- for a procedure_or_entry_call, the procedure_name or
6514 -- procedure_prefix of the procedure_call_statement shall denote
6515 -- an entry renamed by a procedure, or (a view of) a primitive
6516 -- subprogram of a limited interface whose first parameter is
6517 -- a controlling parameter.
6522 then
6523 Error_Msg_N
6528 -- Check that this is not a call to a protected procedure or entry from
6529 -- within a protected function.
6533 -- Freeze the subprogram name if not in a spec-expression. Note that
6534 -- we freeze procedure calls as well as function calls. Procedure calls
6535 -- are not frozen according to the rules (RM 13.14(14)) because it is
6536 -- impossible to have a procedure call to a non-frozen procedure in
6537 -- pure Ada, but in the code that we generate in the expander, this
6538 -- rule needs extending because we can generate procedure calls that
6539 -- need freezing.
6541 -- In Ada 2012, expression functions may be called within pre/post
6542 -- conditions of subsequent functions or expression functions. Such
6543 -- calls do not freeze when they appear within generated bodies,
6544 -- (including the body of another expression function) which would
6545 -- place the freeze node in the wrong scope. An expression function
6546 -- is frozen in the usual fashion, by the appearance of a real body,
6547 -- or at the end of a declarative part. However an implicit call to
6548 -- an expression function may appear when it is part of a default
6549 -- expression in a call to an initialization procedure, and must be
6550 -- frozen now, even if the body is inserted at a later point.
6551 -- Otherwise, the call freezes the expression if expander is active,
6552 -- for example as part of an object declaration.
6555 and then not In_Spec_Expression
6557 and then
6560 then
6563 -- Force freeze of expression function in call
6572 -- For a predefined operator, the type of the result is the type imposed
6573 -- by context, except for a predefined operation on universal fixed.
6574 -- Otherwise the type of the call is the type returned by the subprogram
6575 -- being called.
6582 -- If the subprogram returns an array type, and the context requires the
6583 -- component type of that array type, the node is really an indexing of
6584 -- the parameterless call. Resolve as such. A pathological case occurs
6585 -- when the type of the component is an access to the array type. In
6586 -- this case the call is truly ambiguous. If the call is to an intrinsic
6587 -- subprogram, it can't be an indexed component. This check is necessary
6588 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6589 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6590 -- pointers to the same array), the compiler gets confused and does an
6591 -- infinite recursion.
6594 and then
6597 or else
6600 and then
6603 then
6604 declare
6609 begin
6610 -- If this is a parameterless call there is no ambiguity and the
6611 -- call has the type of the function.
6620 -- Annotate the tree by creating a call marker in case the
6621 -- original call is transformed by expansion. The call marker
6622 -- is automatically saved for later examination by the ABE
6623 -- Processing phase.
6630 then
6631 Error_Msg_N
6633 else
6636 -- The called entity may be an explicit dereference, in which
6637 -- case there is no entity to set.
6645 or else
6647 and then
6649 then
6652 -- Indexed call to a parameterless function
6654 Index_Node :=
6656 Prefix =>
6659 else
6660 -- An Ada 2005 prefixed call to a primitive operation
6661 -- whose first parameter is the prefix. This prefix was
6662 -- prepended to the parameter list, which is actually a
6663 -- list of indexes. Remove the prefix in order to build
6664 -- the proper indexed component.
6666 Index_Node :=
6668 Prefix =>
6671 Parameter_Associations =>
6672 New_List
6677 -- Preserve the parenthesis count of the node
6681 -- Since we are correcting a node classification error made
6682 -- by the parser, we call Replace rather than Rewrite.
6693 -- Annotate the tree by creating a call marker in case
6694 -- the original call is transformed by expansion. The call
6695 -- marker is automatically saved for later examination by
6696 -- the ABE Processing phase.
6707 else
6708 -- If the called function is not declared in the main unit and it
6709 -- returns the limited view of type then use the available view (as
6710 -- is done in Try_Object_Operation) to prevent back-end confusion;
6711 -- for the function entity itself. The call must appear in a context
6712 -- where the nonlimited view is available. If the function entity is
6713 -- in the extended main unit then no action is needed, because the
6714 -- back end handles this case. In either case the type of the call
6715 -- is the nonlimited view.
6719 then
6726 else
6731 -- In the case where the call is to an overloaded subprogram, Analyze
6732 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6733 -- such a case Normalize_Actuals needs to be called once more to order
6734 -- the actuals correctly. Otherwise the call will have the ordering
6735 -- given by the last overloaded subprogram whether this is the correct
6736 -- one being called or not.
6743 -- In any case, call is fully resolved now. Reset Overload flag, to
6744 -- prevent subsequent overload resolution if node is analyzed again
6749 -- A Ghost entity must appear in a specific context
6755 -- If we are calling the current subprogram from immediately within its
6756 -- body, then that is the case where we can sometimes detect cases of
6757 -- infinite recursion statically. Do not try this in case restriction
6758 -- No_Recursion is in effect anyway, and do it only for source calls.
6763 -- Issue warning for possible infinite recursion in the absence
6764 -- of the No_Recursion restriction.
6770 then
6771 -- Here we detected and flagged an infinite recursion, so we do
6772 -- not need to test the case below for further warnings. Also we
6773 -- are all done if we now have a raise SE node.
6779 -- If call is to immediately containing subprogram, then check for
6780 -- the case of a possible run-time detectable infinite recursion.
6782 else
6786 -- Ada 2022 (AI12-0075): Static functions are never allowed
6787 -- to make a recursive call, as specified by 6.8(5.4/5).
6790 Error_Msg_N
6799 -- Although in general case, recursion is not statically
6800 -- checkable, the case of calling an immediately containing
6801 -- subprogram is easy to catch.
6807 -- If the recursive call is to a parameterless subprogram,
6808 -- then even if we can't statically detect infinite
6809 -- recursion, this is pretty suspicious, and we output a
6810 -- warning. Furthermore, we will try later to detect some
6811 -- cases here at run time by expanding checking code (see
6812 -- Detect_Infinite_Recursion in package Exp_Ch6).
6814 -- If the recursive call is within a handler, do not emit a
6815 -- warning, because this is a common idiom: loop until input
6816 -- is correct, catch illegal input in handler and restart.
6822 then
6823 -- For the case of a procedure call. We give the message
6824 -- only if the call is the first statement in a sequence
6825 -- of statements, or if all previous statements are
6826 -- simple assignments. This is simply a heuristic to
6827 -- decrease false positives, without losing too many good
6828 -- warnings. The idea is that these previous statements
6829 -- may affect global variables the procedure depends on.
6830 -- We also exclude raise statements, that may arise from
6831 -- constraint checks and are probably unrelated to the
6832 -- intended control flow.
6836 then
6837 declare
6839 begin
6843 | N_Raise_Constraint_Error
6844 then
6853 -- Do not give warning if we are in a conditional context
6855 declare
6857 begin
6863 then
6868 -- Here warning is to be issued
6884 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6888 -- If subprogram name is a predefined operator, it was given in
6889 -- functional notation. Replace call node with operator node, so
6890 -- that actuals can be resolved appropriately.
6902 -- Create a transient scope if the resulting type requires it
6904 -- There are several notable exceptions:
6906 -- a) In init procs, the transient scope overhead is not needed, and is
6907 -- even incorrect when the call is a nested initialization call for a
6908 -- component whose expansion may generate adjust calls. However, if the
6909 -- call is some other procedure call within an initialization procedure
6910 -- (for example a call to Create_Task in the init_proc of the task
6911 -- run-time record) a transient scope must be created around this call.
6913 -- b) Enumeration literal pseudo-calls need no transient scope
6915 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6916 -- functions) do not use the secondary stack even though the return
6917 -- type may be unconstrained.
6919 -- d) Calls to a build-in-place function, since such functions may
6920 -- allocate their result directly in a target object, and cases where
6921 -- the result does get allocated in the secondary stack are checked for
6922 -- within the specialized Exp_Ch6 procedures for expanding those
6923 -- build-in-place calls.
6925 -- e) Calls to inlinable expression functions do not use the secondary
6926 -- stack (since the call will be replaced by its returned object).
6928 -- f) If the subprogram is marked Inline_Always, then even if it returns
6929 -- an unconstrained type the call does not require use of the secondary
6930 -- stack. However, inlining will only take place if the body to inline
6931 -- is already present. It may not be available if e.g. the subprogram is
6932 -- declared in a child instance.
6934 -- g) If the subprogram is a static expression function and the call is
6935 -- a static call (the actuals are all static expressions), then we never
6936 -- want to create a transient scope (this could occur in the case of a
6937 -- static string-returning call).
6943 then
6951 then
6954 -- A return statement from an ignored Ghost function does not use the
6955 -- secondary stack (or any other one).
6957 elsif Expander_Active
6961 then
6964 -- If the call appears within the bounds of a loop, it will be
6965 -- rewritten and reanalyzed, nothing left to do here.
6972 -- A protected function cannot be called within the definition of the
6973 -- enclosing protected type, unless it is part of a pre/postcondition
6974 -- on another protected operation. This may appear in the entry wrapper
6975 -- created for an entry with preconditions.
6980 and then not In_Spec_Expression
6982 then
6983 Error_Msg_NE
6987 -- Propagate interpretation to actuals, and add default expressions
6988 -- where needed.
6993 -- Overloaded literals are rewritten as function calls, for purpose of
6994 -- resolution. After resolution, we can replace the call with the
6995 -- literal itself.
7001 -- Avoid validation, since it is a static function call
7007 -- If the subprogram is not global, then kill all saved values and
7008 -- checks. This is a bit conservative, since in many cases we could do
7009 -- better, but it is not worth the effort. Similarly, we kill constant
7010 -- values. However we do not need to do this for internal entities
7011 -- (unless they are inherited user-defined subprograms), since they
7012 -- are not in the business of molesting local values.
7014 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
7015 -- kill all checks and values for calls to global subprograms. This
7016 -- takes care of the case where an access to a local subprogram is
7017 -- taken, and could be passed directly or indirectly and then called
7018 -- from almost any context.
7020 -- Note: we do not do this step till after resolving the actuals. That
7021 -- way we still take advantage of the current value information while
7022 -- scanning the actuals.
7024 -- We suppress killing values if we are processing the nodes associated
7025 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
7026 -- type kills all the values as part of analyzing the code that
7027 -- initializes the dispatch tables.
7031 or else Suppress_Value_Tracking_On_Call
7036 then
7037 Kill_Current_Values;
7040 -- If we are warning about unread OUT parameters, this is the place to
7041 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7042 -- after the above call to Kill_Current_Values (since that call clears
7043 -- the Last_Assignment field of all local variables).
7048 then
7049 declare
7053 begin
7063 then
7073 -- If the subprogram is a primitive operation, check whether or not
7074 -- it is a correct dispatching call.
7079 -- If the subprogram is an abstract operation, then flag an error
7085 -- If this is a dispatching call, generate the appropriate reference,
7086 -- for better source navigation in GNAT Studio.
7091 -- Normal case, not a dispatching call: generate a call reference
7093 else
7101 -- Check for violation of restriction No_Specific_Termination_Handlers
7102 -- and warn on a potentially blocking call to Abort_Task.
7106 or else
7108 then
7115 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7116 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7117 -- need to check the second argument to determine whether it is an
7118 -- absolute or relative timing event.
7123 then
7127 -- Issue an error for a call to an eliminated subprogram. This routine
7128 -- will not perform the check if the call appears within a default
7129 -- expression.
7133 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7134 -- class-wide and the call dispatches on result in a context that does
7135 -- not provide a tag, the call raises Program_Error.
7138 and then In_Instance
7143 then
7144 -- Verify that none of the formals are controlling
7146 declare
7150 begin
7172 -- Check for calling a function with OUT or IN OUT parameter when the
7173 -- calling context (us right now) is not Ada 2012, so does not allow
7174 -- OUT or IN OUT parameters in function calls. Functions declared in
7175 -- a predefined unit are OK, as they may be called indirectly from a
7176 -- user-declared instantiation.
7182 then
7187 -- Check the dimensions of the actuals in the call. For function calls,
7188 -- propagate the dimensions from the returned type to N.
7192 -- All done, evaluate call and deal with elaboration issues
7200 -- Annotate the tree by creating a call marker in case the original call
7201 -- is transformed by expansion. The call marker is automatically saved
7202 -- for later examination by the ABE Processing phase.
7210 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7211 -- expression function, then we want to "inline" the call, replacing
7212 -- it with the folded static result. This is not done if the checking
7213 -- for a potentially static expression is enabled or if an error has
7214 -- been posted on the call (which may be due to the check for recursive
7215 -- calls, in which case we don't want to fall into infinite recursion
7216 -- when doing the inlining).
7218 if not Checking_Potentially_Static_Expression
7222 then
7225 -- In GNATprove mode, expansion is disabled, but we want to inline some
7226 -- subprograms to facilitate formal verification. Indirect calls through
7227 -- a subprogram type or within a generic cannot be inlined. Inlining is
7228 -- performed only for calls subject to SPARK_Mode on.
7230 elsif GNATprove_Mode
7233 and then not Inside_A_Generic
7234 then
7241 -- Nothing to do if the subprogram is not eligible for inlining in
7242 -- GNATprove mode, or inlining is disabled with switch -gnatdm
7246 or else Debug_Flag_M
7247 then
7250 -- Calls cannot be inlined inside assertions, as GNATprove treats
7251 -- assertions as logic expressions. Only issue a message when the
7252 -- body has been seen, otherwise this leads to spurious messages
7253 -- on expression functions.
7256 Cannot_Inline
7260 -- Calls cannot be inlined inside default expressions
7263 Cannot_Inline
7266 -- Calls cannot be inlined inside quantified expressions, which
7267 -- are left in expression form for GNATprove. Since these
7268 -- expressions are only preanalyzed, we need to detect the failure
7269 -- to inline outside of the case for Full_Analysis below.
7272 Cannot_Inline
7275 -- Inlining should not be performed during preanalysis
7279 -- Do not inline calls inside expression functions or functions
7280 -- generated by the front end for subtype predicates, as this
7281 -- would prevent interpreting them as logical formulas in
7282 -- GNATprove. Only issue a message when the body has been seen,
7283 -- otherwise this leads to spurious messages on callees that
7284 -- are themselves expression functions.
7287 and then
7292 then
7295 then
7297 Cannot_Inline
7302 Cannot_Inline
7307 Cannot_Inline
7311 else
7312 Cannot_Inline
7318 -- Cannot inline a call inside the definition of a record type,
7319 -- typically inside the constraints of the type. Calls in
7320 -- default expressions are also not inlined, but this is
7321 -- filtered out above when testing In_Default_Expr.
7324 Cannot_Inline
7327 -- With the one-pass inlining technique, a call cannot be
7328 -- inlined if the corresponding body has not been seen yet.
7331 Cannot_Inline
7334 -- Nothing to do if there is no body to inline, indicating that
7335 -- the subprogram is not suitable for inlining in GNATprove
7336 -- mode.
7341 -- Calls cannot be inlined inside potentially unevaluated
7342 -- expressions, as this would create complex actions inside
7343 -- expressions, that are not handled by GNATprove.
7346 Cannot_Inline
7350 -- Calls cannot be inlined inside the conditions of while
7351 -- loops, as this would create complex actions inside
7352 -- the condition, that are not handled by GNATprove.
7355 Cannot_Inline
7358 -- Do not inline calls which would possibly lead to missing a
7359 -- type conversion check on an input parameter.
7362 Cannot_Inline
7366 -- Otherwise, inline the call, issuing an info message when
7367 -- -gnatd_f is set.
7369 else
7371 Error_Msg_NE
7382 -----------------------------
7383 -- Resolve_Case_Expression --
7384 -----------------------------
7392 begin
7405 -- When the expression is of a scalar subtype different from the
7406 -- result subtype, then insert a conversion to ensure the generation
7407 -- of a constraint check.
7417 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7418 -- dynamically tagged must be known statically.
7426 Error_Msg_N
7440 -------------------------------
7441 -- Resolve_Character_Literal --
7442 -------------------------------
7448 begin
7449 -- Verify that the character does belong to the type of the context
7454 -- Wide_Wide_Character literals must always be defined, since the set
7455 -- of wide wide character literals is complete, i.e. if a character
7456 -- literal is accepted by the parser, then it is OK for wide wide
7457 -- character (out of range character literals are rejected).
7462 -- Always accept character literal for type Any_Character, which
7463 -- occurs in error situations and in comparisons of literals, both
7464 -- of which should accept all literals.
7469 -- For Standard.Character or a type derived from it, check that the
7470 -- literal is in range.
7477 -- For Standard.Wide_Character or a type derived from it, check that the
7478 -- literal is in range.
7485 -- If the entity is already set, this has already been resolved in a
7486 -- generic context, or comes from expansion. Nothing else to do.
7491 -- Otherwise we have a user defined character type, and we can use the
7492 -- standard visibility mechanisms to locate the referenced entity.
7494 else
7507 -- If we fall through, then the literal does not match any of the
7508 -- entries of the enumeration type. This isn't just a constraint error
7509 -- situation, it is an illegality (see RM 4.2).
7511 Error_Msg_NE
7515 ---------------------------
7516 -- Resolve_Comparison_Op --
7517 ---------------------------
7519 -- The operands must have compatible types and the boolean context does not
7520 -- participate in the resolution. The first pass verifies that the operands
7521 -- are not ambiguous and sets their type correctly, or to Any_Type in case
7522 -- of ambiguity. If both operands are strings or aggregates, then they are
7523 -- ambiguous even if they carry a single (universal) type.
7531 begin
7540 -- Deal with explicit ambiguity of operands
7544 then
7551 -- Deal with other error cases
7555 T = Any_Character
7556 then
7559 else
7567 -- Resolve the operands if types OK
7576 -- Check comparison on unordered enumeration
7580 Error_Msg_NE
7590 --------------------------------
7591 -- Resolve_Declare_Expression --
7592 --------------------------------
7594 procedure Resolve_Declare_Expression
7597 is
7604 -- Use a tree traversal to replace each occurrence of the name of
7605 -- a local object declared in the construct, with the corresponding
7606 -- entity. This replaces the usual way to perform name capture by
7607 -- visibility, because it is not possible to place on the scope
7608 -- stack the fake scope created for the analysis of the local
7609 -- declarations; such a scope conflicts with the transient scopes
7610 -- that may be generated if the expression includes function calls
7611 -- requiring finalization.
7613 -------------------
7614 -- Replace_Local --
7615 -------------------
7618 begin
7619 -- The identifier may be the prefix of a selected component,
7620 -- but not a selector name, because the local entities do not
7621 -- have a scope that can be named: a selected component whose
7622 -- selector is a homonym of a local entity must denote some
7623 -- global entity.
7628 and then
7631 then
7641 -- Start of processing for Resolve_Declare_Expression
7643 begin
7649 N_Object_Declaration | N_Object_Renaming_Declaration
7651 then
7655 -- Traverse the expression to replace references to local
7656 -- variables that occur within declarations of the
7657 -- declare_expression.
7659 declare
7661 begin
7672 -- The end of the declarative list is a freeze point for the
7673 -- local declarations.
7684 -----------------------------------------
7685 -- Resolve_Discrete_Subtype_Indication --
7686 -----------------------------------------
7688 procedure Resolve_Discrete_Subtype_Indication
7691 is
7695 begin
7703 else
7713 Error_Msg_NE
7716 -- Rewrite the constraint as a range of Typ
7717 -- to allow compilation to proceed further.
7729 else
7733 -- Additionally, we must check that the bounds are compatible
7734 -- with the given subtype, which might be different from the
7735 -- type of the context.
7739 -- ??? If the above check statically detects a Constraint_Error
7740 -- it replaces the offending bound(s) of the range R with a
7741 -- Constraint_Error node. When the itype which uses these bounds
7742 -- is frozen the resulting call to Duplicate_Subexpr generates
7743 -- a new temporary for the bounds.
7745 -- Unfortunately there are other itypes that are also made depend
7746 -- on these bounds, so when Duplicate_Subexpr is called they get
7747 -- a forward reference to the newly created temporaries and Gigi
7748 -- aborts on such forward references. This is probably sign of a
7749 -- more fundamental problem somewhere else in either the order of
7750 -- itype freezing or the way certain itypes are constructed.
7752 -- To get around this problem we call Remove_Side_Effects right
7753 -- away if either bounds of R are a Constraint_Error.
7755 declare
7759 begin
7775 -------------------------
7776 -- Resolve_Entity_Name --
7777 -------------------------
7779 -- Used to resolve identifiers and expanded names
7782 function Is_Assignment_Or_Object_Expression
7785 -- Determine whether node Context denotes an assignment statement or an
7786 -- object declaration whose expression is node Expr.
7789 -- Determine whether Expr is part of an N_Attribute_Reference
7790 -- expression.
7792 ----------------------------------------
7793 -- Is_Assignment_Or_Object_Expression --
7794 ----------------------------------------
7796 function Is_Assignment_Or_Object_Expression
7799 is
7800 begin
7803 then
7806 -- Check whether a construct that yields a name is the expression of
7807 -- an assignment statement or an object declaration.
7810 | N_Explicit_Dereference
7811 | N_Indexed_Component
7812 | N_Selected_Component
7813 | N_Slice
7815 or else
7817 | N_Unchecked_Type_Conversion
7819 then
7820 return
7821 Is_Assignment_Or_Object_Expression
7825 -- Otherwise the context is not an assignment statement or an object
7826 -- declaration.
7828 else
7833 -----------------------------
7834 -- Is_Attribute_Expression --
7835 -----------------------------
7839 begin
7844 -- Prevent the search from going too far
7856 -- Local variables
7861 -- Start of processing for Resolve_Entity_Name
7863 begin
7864 -- If garbage from errors, set to Any_Type and return
7871 -- Replace named numbers by corresponding literals. Note that this is
7872 -- the one case where Resolve_Entity_Name must reset the Etype, since
7873 -- it is currently marked as universal.
7883 -- For enumeration literals, we need to make sure that a proper style
7884 -- check is done, since such literals are overloaded, and thus we did
7885 -- not do a style check during the first phase of analysis.
7891 -- Case of (sub)type name appearing in a context where an expression
7892 -- is expected. This is legal if occurrence is a current instance.
7893 -- See RM 8.6 (17/3). It is also legal if the expression is
7894 -- part of a choice pattern for a case stmt/expr having a
7895 -- non-discrete selecting expression.
7901 -- Any other use is an error
7903 else
7904 Error_Msg_N
7908 -- Check discriminant use if entity is discriminant in current scope,
7909 -- i.e. discriminant of record or concurrent type currently being
7910 -- analyzed. Uses in corresponding body are unrestricted.
7915 then
7918 -- A parameterless generic function cannot appear in a context that
7919 -- requires resolution.
7924 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7925 -- array types (i.e. bounds and length) are legal.
7933 or else Is_Assignment_Or_Object_Expression
7936 then
7941 -- In all other cases, just do the possible static evaluation
7943 else
7944 -- A deferred constant that appears in an expression must have a
7945 -- completion, unless it has been removed by in-place expansion of
7946 -- an aggregate. A constant that is a renaming does not need
7947 -- initialization.
7953 and then not In_Spec_Expression
7956 then
7960 then
7962 else
7963 Error_Msg_N
7973 -- When the entity appears in a parameter association, retrieve the
7974 -- related subprogram call.
7982 -- The following checks are only relevant when SPARK_Mode is on as
7983 -- they are not standard Ada legality rules.
7987 -- An effectively volatile object for reading must appear in
7988 -- non-interfering context (SPARK RM 7.1.3(10)).
7992 and then
7994 then
7995 SPARK_Msg_N
8000 -- Check for possible elaboration issues with respect to reads of
8001 -- variables. The act of renaming the variable is not considered a
8002 -- read as it simply establishes an alias.
8004 if Legacy_Elaboration_Checks
8006 and then Dynamic_Elaboration_Checks
8008 then
8013 -- The variable may eventually become a constituent of a single
8014 -- protected/task type. Record the reference now and verify its
8015 -- legality when analyzing the contract of the variable
8016 -- (SPARK RM 9.3).
8022 -- A Ghost entity must appear in a specific context
8029 -- We may be resolving an entity within expanded code, so a reference to
8030 -- an entity should be ignored when calculating effective use clauses to
8031 -- avoid inappropriate marking.
8038 -------------------
8039 -- Resolve_Entry --
8040 -------------------
8052 -- If the bounds of the entry family being called depend on task
8053 -- discriminants, build a new index subtype where a discriminant is
8054 -- replaced with the value of the discriminant of the target task.
8055 -- The target task is the prefix of the entry name in the call.
8057 -----------------------
8058 -- Actual_Index_Type --
8059 -----------------------
8069 -- If the bound is given by a discriminant, replace with a reference
8070 -- to the discriminant of the same name in the target task. If the
8071 -- entry name is the target of a requeue statement and the entry is
8072 -- in the current protected object, the bound to be used is the
8073 -- discriminal of the object (see Apply_Range_Check for details of
8074 -- the transformation).
8076 -----------------------------
8077 -- Actual_Discriminant_Ref --
8078 -----------------------------
8084 begin
8089 then
8095 then
8096 -- Note: here Bound denotes a discriminant of the corresponding
8097 -- record type tskV, whose discriminal is a formal of the
8098 -- init-proc tskVIP. What we want is the body discriminal,
8099 -- which is associated to the discriminant of the original
8100 -- concurrent type tsk.
8102 return New_Occurrence_Of
8105 else
8106 Ref :=
8116 -- Start of processing for Actual_Index_Type
8118 begin
8121 then
8124 else
8138 -- Start of processing for Resolve_Entry
8140 begin
8141 -- Find name of entry being called, and resolve prefix of name with its
8142 -- own type. The prefix can be overloaded, and the name and signature of
8143 -- the entry must be taken into account.
8147 -- Case of dealing with entry family within the current tasks
8151 else
8157 -- Entry call to an entry (or entry family) in the current task. This
8158 -- is legal even though the task will deadlock. Rewrite as call to
8159 -- current task.
8161 -- This can also be a call to an entry in an enclosing task. If this
8162 -- is a single task, we have to retrieve its name, because the scope
8163 -- of the entry is the task type, not the object. If the enclosing
8164 -- task is a task type, the identity of the task is given by its own
8165 -- self variable.
8167 -- Finally this can be a requeue on an entry of the same task or
8168 -- protected object.
8175 then
8176 -- S is an enclosing task or protected object. The concurrent
8177 -- declaration has been converted into a type declaration, and
8178 -- the object itself has an object declaration that follows
8179 -- the type in the same declarative part.
8191 -- Call to current task. Will be transformed into call to Self
8198 New_N :=
8201 Selector_Name =>
8208 then
8209 -- Use the entry name (which must be unique at this point) to find
8210 -- the prefix that returns the corresponding task/protected type.
8212 declare
8218 begin
8240 -- We do not resolve the prefix because an Entry_Family has no type,
8241 -- although it has the semantics of an array since it can be indexed.
8242 -- In order to perform the associated range check, we would need to
8243 -- build an array type on the fly and set it on the prefix, but this
8244 -- would be wasteful since only the index type matters. Therefore we
8245 -- attach this index type directly, so that Actual_Index_Expression
8246 -- can pick it up later in order to generate the range check.
8253 -- Generate a reference for the index when it denotes an entity
8259 -- Up to this point the expression could have been the actual in a
8260 -- simple entry call, and be given by a named association.
8264 else
8270 ------------------------
8271 -- Resolve_Entry_Call --
8272 ------------------------
8283 begin
8284 -- We kill all checks here, because it does not seem worth the effort to
8285 -- do anything better, an entry call is a big operation.
8287 Kill_All_Checks;
8289 -- Processing of the name is similar for entry calls and protected
8290 -- operation calls. Once the entity is determined, we can complete
8291 -- the resolution of the actuals.
8293 -- The selector may be overloaded, in the case of a protected object
8294 -- with overloaded functions. The type of the context is used for
8295 -- resolution.
8300 then
8301 declare
8305 begin
8324 -- Simple entry or protected operation call
8337 -- Call to member of entry family
8344 -- We cannot in general check the maximum depth of protected entry calls
8345 -- at compile time. But we can tell that any protected entry call at all
8346 -- violates a specified nesting depth of zero.
8352 -- Use context type to disambiguate a protected function that can be
8353 -- called without actuals and that returns an array type, and where the
8354 -- argument list may be an indexing of the returned value.
8359 and then
8365 and then
8366 Covers
8369 then
8370 declare
8373 begin
8374 Index_Node :=
8376 Prefix =>
8380 -- Since we are correcting a node classification error made by the
8381 -- parser, we call Replace rather than Rewrite.
8394 then
8395 -- Note the entity being called before rewriting the call, so that
8396 -- it appears used at this point.
8400 -- Rewrite as call to the precondition wrapper, adding the task
8401 -- object to the list of actuals. If the call is to a member of an
8402 -- entry family, include the index as well.
8404 declare
8408 begin
8417 New_Call :=
8419 Name =>
8424 -- Preanalyze and resolve new call. Current procedure is called
8425 -- from Resolve_Call, after which expansion will take place.
8432 -- The operation name may have been overloaded. Order the actuals
8433 -- according to the formals of the resolved entity, and set the return
8434 -- type to that of the operation.
8441 -- Reset the Is_Overloaded flag, since resolution is now completed
8443 -- Simple entry call
8448 -- Call to a member of an entry family
8458 -- Create a call reference to the entry
8466 -- Verify that a procedure call cannot masquerade as an entry
8467 -- call where an entry call is expected.
8472 then
8477 then
8482 then
8487 -- After resolution, entry calls and protected procedure calls are
8488 -- changed into entry calls, for expansion. The structure of the node
8489 -- does not change, so it can safely be done in place. Protected
8490 -- function calls must keep their structure because they are
8491 -- subexpressions.
8495 -- A protected operation that is not a function may modify the
8496 -- corresponding object, and cannot apply to a constant. If this
8497 -- is an internal call, the prefix is the type itself.
8503 then
8504 Error_Msg_N
8506 Entry_Name);
8509 declare
8512 begin
8513 Entry_Call :=
8518 -- Inherit relevant attributes from the original call
8520 Set_First_Named_Actual
8523 Set_Is_Elaboration_Checks_OK_Node
8526 Set_Is_Elaboration_Warnings_OK_Node
8529 Set_Is_SPARK_Mode_On_Node
8536 -- Protected functions can return on the secondary stack, in which case
8537 -- we must trigger the transient scope mechanism.
8539 elsif Expander_Active
8541 then
8545 -- Now we know that this is not a call to a function that returns an
8546 -- array type; moreover, we know the name of the called entry. Detect
8547 -- overlapping actuals, just like for a subprogram call.
8552 -------------------------
8553 -- Resolve_Equality_Op --
8554 -------------------------
8556 -- The operands must have compatible types and the boolean context does not
8557 -- participate in the resolution. The first pass verifies that the operands
8558 -- are not ambiguous and sets their type correctly, or to Any_Type in case
8559 -- of ambiguity. If both operands are strings, aggregates, allocators, or
8560 -- null, they are ambiguous even if they carry a single (universal) type.
8569 -- For any object, '[Unchecked_]Access of such object can never be
8570 -- passed as an operand to the Universal_Access equality operators.
8571 -- This is so because the expected type for Obj'Access in a call to
8572 -- these operators, whose formals are of type Universal_Access, is
8573 -- Universal_Access, and Universal_Access does not have a designated
8574 -- type. For more details, see RM 3.10.2(2/2) and 6.4.1(3).
8577 -- Check RM 4.5.2(9.6/2) on the given designated object types
8580 -- Check RM 4.5.2(9.7/2) on the given designated subprogram types
8583 -- The resolution rule for if expressions requires that each such must
8584 -- have a unique type. This means that if several dependent expressions
8585 -- are of a non-null anonymous access type, and the context does not
8586 -- impose an expected type (as can be the case in an equality operation)
8587 -- the expression must be rejected.
8590 -- Attempt to explain the nature of a redundant comparison with True. If
8591 -- the expression N is too complex, this routine issues a general error
8592 -- message.
8595 -- In the case of allocators and access attributes, the context must
8596 -- provide an indication of the specific access type to be used. If
8597 -- one operand is of such a "generic" access type, check whether there
8598 -- is a specific visible access type that has the same designated type.
8599 -- This is semantically dubious, and of no interest to any real code,
8600 -- but c48008a makes it all worthwhile.
8603 -- Returns True iff the parent node is a and/or/xor operation that
8604 -- could be the cause of confused priorities. Note that if the not is
8605 -- in parens, then False is returned.
8607 ----------------------------
8608 -- Check_Access_Attribute --
8609 ----------------------------
8612 begin
8615 then
8616 Error_Msg_N
8622 -----------------------------------
8623 -- Check_Designated_Object_Types --
8624 -----------------------------------
8627 begin
8631 then
8632 Error_Msg_N
8640 ---------------------------------------
8641 -- Check_Designated_Subprogram_Types --
8642 ---------------------------------------
8645 begin
8647 Error_Msg_N
8655 -------------------------
8656 -- Check_If_Expression --
8657 -------------------------
8663 begin
8670 then
8676 ------------------------
8677 -- Explain_Redundancy --
8678 ------------------------
8685 begin
8688 -- Strip the operand down to an entity
8690 loop
8693 else
8698 -- The construct denotes an entity
8703 -- Do not generate an error message when the comparison is done
8704 -- against the enumeration literal Standard.True.
8708 -- Build a customized error message
8735 -- The construct is too complex to disect, issue a general message
8737 else
8742 -----------------------------
8743 -- Find_Unique_Access_Type --
8744 -----------------------------
8751 begin
8753 then
8757 then
8759 else
8771 then
8784 ----------------------------------
8785 -- Suspicious_Prio_For_Equality --
8786 ----------------------------------
8791 begin
8792 -- Check if parent node is one of and/or/xor, not parenthesized
8793 -- explicitly, and its own parent is not of this kind. Otherwise,
8794 -- it's a case of chained Boolean conditions which is likely well
8795 -- parenthesized.
8800 then
8801 declare
8805 else
8807 begin
8808 -- Compar may have been rewritten, for example from (a /= b)
8809 -- into not (a = b). Use the Original_Node instead.
8813 -- If the other argument of the and/or/xor is also a
8814 -- comparison, or another and/or/xor then most likely
8815 -- the priorities are correctly set.
8820 else
8825 -- Start of processing for Resolve_Equality_Op
8827 begin
8836 -- Deal with explicit ambiguity of operands
8840 then
8844 else
8845 -- Deal with other error cases
8849 T = Any_Character
8850 then
8853 else
8862 then
8871 -- If expressions must have a single type, and if the context does
8872 -- not impose one the dependent expressions cannot be anonymous
8873 -- access types.
8875 -- Why no similar processing for case expressions???
8880 then
8885 -- RM 4.5.2(9.5/2): At least one of the operands of the equality
8886 -- operators for universal_access shall be of type universal_access,
8887 -- or both shall be of access-to-object types, or both shall be of
8888 -- access-to-subprogram types (RM 4.5.2(9.5/2)).
8893 then
8894 -- RM 4.5.2(9.6/2): When both are of access-to-object types, the
8895 -- designated types shall be the same or one shall cover the other
8896 -- and if the designated types are elementary or array types, then
8897 -- the designated subtypes shall statically match.
8901 then
8902 Check_Designated_Object_Types
8905 -- RM 4.5.2(9.7/2): When both are of access-to-subprogram types,
8906 -- the designated profiles shall be subtype conformant.
8910 then
8911 Check_Designated_Subprogram_Types
8916 -- Check another case of equality operators for universal_access
8926 -- AI12-0413: user-defined primitive equality of an untagged record
8927 -- type hides the predefined equality operator, including within a
8928 -- generic, and if it is declared abstract, results in an illegal
8929 -- instance if the operator is used in the spec, or in the raising
8930 -- of Program_Error if used in the body of an instance.
8933 and then In_Instance
8935 then
8936 declare
8941 begin
8945 then
8951 else
8961 -- If the unique type is a class-wide type then it will be expanded
8962 -- into a dispatching call to the predefined primitive. Therefore we
8963 -- check here for potential violation of such restriction.
8969 -- Only warn for redundant equality comparison to True for objects
8970 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8971 -- other expressions, it may be a matter of preference to write
8972 -- "Expr = True" or "Expr".
8974 if Warn_On_Redundant_Constructs
8979 and then
8981 or else
8983 then
8984 Error_Msg_N -- CODEFIX
8989 -- Warn on a (in)equality between boolean values which is not
8990 -- parenthesized when the parent expression is one of and/or/xor, as
8991 -- this is interpreted as (a = b) op c where most likely a = (b op c)
8992 -- was intended. Do not generate a warning in generic instances, as
8993 -- the problematic expression may be implicitly parenthesized in
8994 -- the generic itself if one of the operators is a generic formal.
8995 -- Also do not generate a warning for generated equality, for
8996 -- example from rewritting a membership test.
8998 if Warn_On_Questionable_Missing_Parens
8999 and then not In_Instance
9002 and then Suspicious_Prio_For_Equality
9003 then
9012 -- If this is an inequality, it may be the implicit inequality
9013 -- created for a user-defined operation, in which case the corres-
9014 -- ponding equality operation is not intrinsic, and the operation
9015 -- cannot be constant-folded. Else fold.
9020 or else
9022 then
9028 then
9034 ----------------------------------
9035 -- Resolve_Explicit_Dereference --
9036 ----------------------------------
9044 -- The candidate prefix type, if overloaded
9049 begin
9053 -- A useful optimization: check whether the dereference denotes an
9054 -- element of a container, and if so rewrite it as a call to the
9055 -- corresponding Element function.
9057 -- Disabled for now, on advice of ARG. A more restricted form of the
9058 -- predicate might be acceptable ???
9060 -- if Is_Container_Element (N) then
9061 -- return;
9062 -- end if;
9066 -- Use the context type to select the prefix that has the correct
9067 -- designated type. Keep the first match, which will be the inner-
9068 -- most.
9075 then
9080 -- Remove access types that do not match, but preserve access
9081 -- to subprogram interpretations, in case a further dereference
9082 -- is needed (see below).
9095 else
9096 -- If no interpretation covers the designated type of the prefix,
9097 -- this is the pathological case where not all implementations of
9098 -- the prefix allow the interpretation of the node as a call. Now
9099 -- that the expected type is known, Remove other interpretations
9100 -- from prefix, rewrite it as a call, and resolve again, so that
9101 -- the proper call node is generated.
9112 New_N :=
9114 Name =>
9125 -- If not overloaded, resolve P with its own type
9127 else
9131 -- If the prefix might be null, add an access check
9135 then
9139 -- If the designated type is a packed unconstrained array type, and the
9140 -- explicit dereference is not in the context of an attribute reference,
9141 -- then we must compute and set the actual subtype, since it is needed
9142 -- by Gigi. The reason we exclude the attribute case is that this is
9143 -- handled fine by Gigi, and in fact we use such attributes to build the
9144 -- actual subtype. We also exclude generated code (which builds actual
9145 -- subtypes directly if they are needed).
9151 then
9157 -- Note: No Eval processing is required for an explicit dereference,
9158 -- because such a name can never be static.
9162 -------------------------------------
9163 -- Resolve_Expression_With_Actions --
9164 -------------------------------------
9169 -- True if Act is an action of a declare_expression that is allowed in a
9170 -- static declare_expression.
9173 -- True if all actions of N are allowed in a static declare_expression.
9176 -- Expr is an expression with compile-time-known value. This returns the
9177 -- literal node that reprsents that value.
9179 -------------------
9180 -- OK_For_Static --
9181 -------------------
9184 begin
9189 then
9199 -- No other declarations, nor even pragmas, are allowed in a
9200 -- declare expression, so if we see something else, it must be
9201 -- an internally generated expression_with_actions.
9208 -----------------------
9209 -- All_OK_For_Static --
9210 -----------------------
9214 begin
9226 -----------------
9227 -- Get_Literal --
9228 -----------------
9233 begin
9238 else
9247 pragma Assert
9253 -- Local variables
9257 -- Start of processing for Resolve_Expression_With_Actions
9259 begin
9266 -- If the value of the expression is known at compile time, and all
9267 -- of the actions (if any) are suitable, then replace the declare
9268 -- expression with its expression. This allows the declare expression
9269 -- as a whole to be static if appropriate. See AI12-0368.
9275 Rewrite
9282 ----------------------------------
9283 -- Resolve_Generalized_Indexing --
9284 ----------------------------------
9288 begin
9293 ---------------------------
9294 -- Resolve_If_Expression --
9295 ---------------------------
9299 -- When a dependent expression is of a subtype different from
9300 -- the context subtype, then insert a qualification to ensure
9301 -- the generation of a constraint check. This was previously
9302 -- for scalar types. For array types apply a length check, given
9303 -- that the context in general allows sliding, while a qualified
9304 -- expression forces equality of bounds.
9307 -- So in most cases the type of the If_Expression and of its
9308 -- dependent expressions is that of the context. However, if
9309 -- the expression is the index of an Indexed_Component, we must
9310 -- ensure that a proper index check is applied, rather than a
9311 -- range check on the index type (which might be discriminant
9312 -- dependent). In this case we resolve with the base type of the
9313 -- index type, and the index check is generated in the resolution
9314 -- of the indexed_component above.
9316 -----------------
9317 -- Apply_Check --
9318 -----------------
9324 begin
9329 or else Inside_A_Generic
9330 then
9336 else
9346 -- Local variables
9352 -- Start of processing for Resolve_If_Expression
9354 begin
9355 -- Defend against malformed expressions
9364 then
9383 -- If ELSE expression present, just resolve using the determined type
9384 -- If type is universal, resolve to any member of the class.
9393 else
9401 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9402 -- dynamically tagged must be known statically.
9407 then
9413 -- If no ELSE expression is present, root type must be Standard.Boolean
9414 -- and we provide a Standard.True result converted to the appropriate
9415 -- Boolean type (in case it is a derived boolean type).
9418 Else_Expr :=
9423 else
9437 ----------------------------------
9438 -- Resolve_Implicit_Dereference --
9439 ----------------------------------
9444 begin
9445 -- In an instance the proper view may not always be correct for
9446 -- private types, see e.g. Sem_Type.Covers for similar handling.
9451 and then In_Instance
9452 then
9463 -------------------------------
9464 -- Resolve_Indexed_Component --
9465 -------------------------------
9473 begin
9481 -- Use the context type to select the prefix that yields the correct
9482 -- component type.
9484 declare
9490 begin
9497 and then
9498 Covers
9501 then
9510 else
9516 else
9527 else
9534 -- If the prefix's type is an access type, get to the real array type.
9535 -- Note: we do not apply an access check because an explicit dereference
9536 -- will be introduced later, and the check will happen there.
9542 -- If name was overloaded, set component type correctly now.
9543 -- If a misplaced call to an entry family (which has no index types)
9544 -- return. Error will be diagnosed from calling context.
9548 else
9555 -- The prefix may have resolved to a string literal, in which case its
9556 -- etype has a special representation. This is only possible currently
9557 -- if the prefix is a static concatenation, written in functional
9558 -- notation.
9563 else
9578 -- Do not generate the warning on suspicious index if we are analyzing
9579 -- package Ada.Tags; otherwise we will report the warning with the
9580 -- Prims_Ptr field of the dispatch table.
9583 or else not
9585 then
9590 -- If the array type is atomic and the component is not, then this is
9591 -- worth a warning before Ada 2022, since we have a situation where the
9592 -- access to the component may cause extra read/writes of the atomic
9593 -- object, or partial word accesses, both of which may be unexpected.
9599 and then Has_Atomic_Components
9603 then
9604 Error_Msg_N
9606 Error_Msg_N
9611 -----------------------------
9612 -- Resolve_Integer_Literal --
9613 -----------------------------
9616 begin
9621 --------------------------------
9622 -- Resolve_Intrinsic_Operator --
9623 --------------------------------
9632 -- If the operand is a literal, it cannot be the expression in a
9633 -- conversion. Use a qualified expression instead.
9635 ---------------------
9636 -- Convert_Operand --
9637 ---------------------
9643 begin
9645 Res :=
9651 else
9658 -- Start of processing for Resolve_Intrinsic_Operator
9660 begin
9661 -- We must preserve the original entity in a generic setting, so that
9662 -- the legality of the operation can be verified in an instance.
9677 -- If the result or operand types are private, rewrite with unchecked
9678 -- conversions on the operands and the result, to expose the proper
9679 -- underlying numeric type.
9684 then
9689 else
9710 then
9711 -- Add explicit conversion where needed, and save interpretations in
9712 -- case operands are overloaded.
9719 else
9725 else
9735 else
9740 --------------------------------------
9741 -- Resolve_Intrinsic_Unary_Operator --
9742 --------------------------------------
9744 procedure Resolve_Intrinsic_Unary_Operator
9747 is
9752 begin
9771 else
9776 ------------------------
9777 -- Resolve_Logical_Op --
9778 ------------------------
9783 begin
9786 -- Predefined operations on scalar types yield the base type. On the
9787 -- other hand, logical operations on arrays yield the type of the
9788 -- arguments (and the context).
9792 else
9796 -- The following test is required because the operands of the operation
9797 -- may be literals, in which case the resulting type appears to be
9798 -- compatible with a signed integer type, when in fact it is compatible
9799 -- only with modular types. If the context itself is universal, the
9800 -- operation is illegal.
9808 Error_Msg_N
9816 then
9820 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
9821 -- is active and the result type is standard Boolean (do not mess with
9822 -- ops that return a nonstandard Boolean type, because something strange
9823 -- is going on).
9825 -- Note: you might expect this replacement to be done during expansion,
9826 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
9827 -- is used, no part of the right operand of an "and" or "or" operator
9828 -- should be executed if the left operand would short-circuit the
9829 -- evaluation of the corresponding "and then" or "or else". If we left
9830 -- the replacement to expansion time, then run-time checks associated
9831 -- with such operands would be evaluated unconditionally, due to being
9832 -- before the condition prior to the rewriting as short-circuit forms
9833 -- during expansion.
9835 if Short_Circuit_And_Or
9838 then
9839 -- Mark the corresponding putative SCO operator as truly a logical
9840 -- (and short-circuit) operator.
9853 -- Case of OR changed to OR ELSE
9855 else
9863 -- Return now, since analysis of the rewritten ops will take care of
9864 -- other reference bookkeeping and expression folding.
9880 ---------------------------------
9881 -- Resolve_Membership_Equality --
9882 ---------------------------------
9887 begin
9888 -- RM 4.5.2(4.1/3): if the type is limited, then it shall have a visible
9889 -- primitive equality operator. This means that we can use the regular
9890 -- visibility-based resolution and reset Entity in order to trigger it.
9895 -- RM 4.5.2(28.1/3): if the type is a record, then the membership test
9896 -- uses the primitive equality for the type [even if it is not visible].
9897 -- We only deal with the untagged case here, because the tagged case is
9898 -- handled uniformly in the expander.
9901 declare
9904 begin
9912 ---------------------------
9913 -- Resolve_Membership_Op --
9914 ---------------------------
9916 -- The context can only be a boolean type, and does not determine the
9917 -- arguments. Arguments should be unambiguous, but the preference rule for
9918 -- universal types applies.
9928 -- Analysis has determined a unique type for the left operand. Use it as
9929 -- the basis to resolve the disjuncts.
9931 ----------------------------
9932 -- Resolve_Set_Membership --
9933 ----------------------------
9938 begin
9939 -- If the left operand is overloaded, find type compatible with not
9940 -- overloaded alternative of the right operand.
9949 else
9954 -- Unclear how to resolve expression if all alternatives are also
9955 -- overloaded.
9961 else
9970 -- Alternative is an expression, a range
9971 -- or a subtype mark.
9975 then
9982 -- Check for duplicates for discrete case
9985 declare
9994 begin
9995 -- Loop checking duplicates. This is quadratic, but giant sets
9996 -- are unlikely in this context so it's a reasonable choice.
10003 | N_Character_Literal
10004 | N_Has_Entity
10005 then
10022 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
10023 -- limited types, evaluation of a membership test uses the predefined
10024 -- equality for the type. This may be confusing to users, and the
10025 -- following warning appears useful for the most common case.
10029 then
10030 Error_Msg_NE
10032 Error_Msg_N
10037 -- Start of processing for Resolve_Membership_Op
10039 begin
10045 Resolve_Set_Membership;
10051 then
10054 -- Ada 2005 (AI-251): Support the following case:
10056 -- type I is interface;
10057 -- type T is tagged ...
10059 -- function Test (O : I'Class) is
10060 -- begin
10061 -- return O in T'Class.
10062 -- end Test;
10064 -- In this case we have nothing else to do. The membership test will be
10065 -- done at run time.
10071 then
10073 else
10077 -- If mixed-mode operations are present and operands are all literal,
10078 -- the only interpretation involves Duration, which is probably not
10079 -- the intention of the programmer.
10094 then
10100 else
10105 -- Here after resolving membership operation
10112 ------------------
10113 -- Resolve_Null --
10114 ------------------
10119 begin
10120 -- Handle restriction against anonymous null access values This
10121 -- restriction can be turned off using -gnatdj.
10123 -- Ada 2005 (AI-231): Remove restriction
10126 and then not Debug_Flag_J
10129 then
10130 -- In the common case of a call which uses an explicitly null value
10131 -- for an access parameter, give specialized error message.
10134 Error_Msg_N
10137 -- Standard message for all other cases (are there any?)
10139 else
10140 Error_Msg_N
10145 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
10146 -- assignment to a null-excluding object.
10151 then
10154 -- Decide whether to generate an if_statement around our
10155 -- null-excluding check to avoid them on certain internal object
10156 -- declarations by looking at the type the current Init_Proc
10157 -- belongs to.
10159 -- Generate:
10160 -- if T1b_skip_null_excluding_check then
10161 -- [constraint_error "access check failed"]
10162 -- end if;
10164 if Needs_Conditional_Null_Excluding_Check
10166 then
10169 Condition =>
10171 New_External_Name
10173 Then_Statements =>
10174 New_List (
10178 -- Otherwise, simply create the check
10180 else
10185 else
10186 Insert_Action
10194 -- In a distributed context, null for a remote access to subprogram may
10195 -- need to be replaced with a special record aggregate. In this case,
10196 -- return after having done the transformation.
10201 then
10205 -- The null literal takes its type from the context
10210 -----------------------
10211 -- Resolve_Op_Concat --
10212 -----------------------
10216 -- We wish to avoid deep recursion, because concatenations are often
10217 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10218 -- operands nonrecursively until we find something that is not a simple
10219 -- concatenation (A in this case). We resolve that, and then walk back
10220 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10221 -- to do the rest of the work at each level. The Parent pointers allow
10222 -- us to avoid recursion, and thus avoid running out of memory. See also
10223 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10228 begin
10229 -- The following code is equivalent to:
10231 -- Resolve_Op_Concat_First (NN, Typ);
10232 -- Resolve_Op_Concat_Arg (N, ...);
10233 -- Resolve_Op_Concat_Rest (N, Typ);
10235 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10236 -- operand is a concatenation.
10238 -- Walk down left operands
10240 loop
10249 -- Now (given the above example) NN is A&B and Op1 is A
10251 -- First resolve Op1 ...
10255 -- ... then walk NN back up until we reach N (where we started), calling
10256 -- Resolve_Op_Concat_Rest along the way.
10258 loop
10265 ---------------------------
10266 -- Resolve_Op_Concat_Arg --
10267 ---------------------------
10269 procedure Resolve_Op_Concat_Arg
10274 is
10278 begin
10280 if Is_Comp
10284 then
10286 else
10290 -- If both Array & Array and Array & Component are visible, there is a
10291 -- potential ambiguity that must be reported.
10296 then
10300 -- If the operation is user-defined and not overloaded use its
10301 -- profile. The operation may be a renaming, in which case it has
10302 -- been rewritten, and we want the original profile.
10307 then
10309 Etype
10313 -- Otherwise an aggregate may match both the array type and the
10314 -- component type.
10316 else
10321 else
10325 then
10326 declare
10331 begin
10336 -- Special-case the error message when the overloading is
10337 -- caused by a function that yields an array and can be
10338 -- called without parameters.
10343 Error_Msg_NE
10345 Error_Msg_NE
10349 else
10357 or else
10359 then
10360 Error_Msg_N -- CODEFIX
10377 then
10378 -- Determine if the out-of-range violation constitutes a
10379 -- warning or an error according to the expression base type,
10380 -- according to Ada 2022 RM 4.9 (35/2).
10383 Apply_Compile_Time_Constraint_Error
10389 Apply_Compile_Time_Constraint_Error
10398 else
10403 else
10410 -----------------------------
10411 -- Resolve_Op_Concat_First --
10412 -----------------------------
10419 begin
10420 -- The parser folds an enormous sequence of concatenations of string
10421 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10422 -- in the right operand. If the expression resolves to a predefined "&"
10423 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10424 -- we give an error. See P_Simple_Expression in Par.Ch4.
10429 then
10444 ----------------------------
10445 -- Resolve_Op_Concat_Rest --
10446 ----------------------------
10452 begin
10461 -- If this is not a static concatenation, but the result is a string
10462 -- type (and not an array of strings) ensure that static string operands
10463 -- have their subtypes properly constructed.
10467 then
10473 ----------------------
10474 -- Resolve_Op_Expon --
10475 ----------------------
10480 begin
10481 -- Catch attempts to do fixed-point exponentiation with universal
10482 -- operands, which is a case where the illegality is not caught during
10483 -- normal operator analysis. This is not done in preanalysis mode
10484 -- since the tree is not fully decorated during preanalysis.
10496 then
10506 then
10515 -- We do the resolution using the base type, because intermediate values
10516 -- in expressions are always of the base type, not a subtype of it.
10521 -- For integer types, right argument must be in Natural range
10536 -- Evaluate the exponentiation operator for dimensioned type
10539 else
10543 -- Set overflow checking bit. Much cleverer code needed here eventually
10544 -- and perhaps the Resolve routines should be separated for the various
10545 -- arithmetic operations, since they will need different processing. ???
10554 --------------------
10555 -- Resolve_Op_Not --
10556 --------------------
10560 -- This function determines if the parent node is a boolean operator or
10561 -- operation (comparison op, membership test, or short circuit form) and
10562 -- the not in question is the left operand of this operation. Note that
10563 -- if the not is in parens, then false is returned.
10565 -----------------------
10566 -- Parent_Is_Boolean --
10567 -----------------------
10570 begin
10573 | N_Op_Boolean
10574 | N_Short_Circuit
10578 -- Local variables
10582 -- Start of processing for Resolve_Op_Not
10584 begin
10585 -- Predefined operations on scalar types yield the base type. On the
10586 -- other hand, logical operations on arrays yield the type of the
10587 -- arguments (and the context).
10591 else
10595 -- Straightforward case of incorrect arguments
10602 -- Special case of probable missing parens
10606 Error_Msg_N
10609 else
10610 Error_Msg_N
10617 -- OK resolution of NOT
10619 else
10620 -- Warn if non-boolean types involved. This is a case like not a < b
10621 -- where a and b are modular, where we will get (not a) < b and most
10622 -- likely not (a < b) was intended.
10624 if Warn_On_Questionable_Missing_Parens
10626 and then Parent_Is_Boolean
10627 then
10631 -- Warn on double negation if checking redundant constructs
10633 if Warn_On_Redundant_Constructs
10638 then
10642 -- Complete resolution and evaluation of NOT
10652 -----------------------------
10653 -- Resolve_Operator_Symbol --
10654 -----------------------------
10656 -- Nothing to be done, all resolved already
10662 begin
10666 ----------------------------------
10667 -- Resolve_Qualified_Expression --
10668 ----------------------------------
10676 begin
10680 -- A qualified expression requires an exact match of the type, class-
10681 -- wide matching is not allowed. However, if the qualifying type is
10682 -- specific and the expression has a class-wide type, it may still be
10683 -- okay, since it can be the result of the expansion of a call to a
10684 -- dispatching function, so we also have to check class-wideness of the
10685 -- type of the expression's original node.
10688 or else
10692 then
10696 -- If the target type is unconstrained, then we reset the type of the
10697 -- result from the type of the expression. For other cases, the actual
10698 -- subtype of the expression is the target type. But we avoid doing it
10699 -- for an allocator since this is not needed and might be problematic.
10704 then
10711 -- If we still have a qualified expression after the static evaluation,
10712 -- then apply a scalar range check if needed. The reason that we do this
10713 -- after the Eval call is that otherwise, the application of the range
10714 -- check may convert an illegal static expression and result in warning
10715 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
10719 then
10723 -- AI12-0100: Once the qualified expression is resolved, check whether
10724 -- operand satisfies a static predicate of the target subtype, if any.
10725 -- In the static expression case, a predicate check failure is an error.
10728 Check_Expression_Against_Static_Predicate
10733 ------------------------------
10734 -- Resolve_Raise_Expression --
10735 ------------------------------
10738 begin
10743 else
10746 -- Apply check for required parentheses in the enclosing
10747 -- context of raise_expressions (RM 11.3 (2)), including default
10748 -- expressions in contexts that can include aspect specifications,
10749 -- and ancestor parts of extension aggregates.
10751 declare
10755 begin
10758 loop
10765 then
10772 if not Parentheses_Found
10774 and then
10776 | N_Floating_Point_Definition
10777 | N_Ordinary_Fixed_Point_Definition
10778 | N_Decimal_Fixed_Point_Definition
10779 | N_Extension_Aggregate
10780 | N_Discriminant_Specification
10781 | N_Parameter_Specification
10782 | N_Formal_Object_Declaration)
10785 and then
10787 then
10788 Error_Msg_N
10790 N);
10796 -------------------
10797 -- Resolve_Range --
10798 -------------------
10805 -- Returns True if N is of the form X'First .. X'Last where X is the
10806 -- same entity for both attributes.
10808 --------------------
10809 -- First_Last_Ref --
10810 --------------------
10816 begin
10821 then
10822 declare
10825 begin
10835 -- Start of processing for Resolve_Range
10837 begin
10843 -- Reanalyze the lower bound after both bounds have been analyzed, so
10844 -- that the range is known to be static or not by now. This may trigger
10845 -- more compile-time evaluation, which is useful for static analysis
10846 -- with GNATprove. This is not needed for compilation or static analysis
10847 -- with CodePeer, as full expansion does that evaluation then.
10854 -- Check for inappropriate range on unordered enumeration type
10858 -- Exclude X'First .. X'Last if X is the same entity for both
10860 and then not First_Last_Ref
10861 then
10863 Error_Msg_NE
10870 -- We have to check the bounds for being within the base range as
10871 -- required for a non-static context. Normally this is automatic and
10872 -- done as part of evaluating expressions, but the N_Range node is an
10873 -- exception, since in GNAT we consider this node to be a subexpression,
10874 -- even though in Ada it is not. The circuit in Sem_Eval could check for
10875 -- this, but that would put the test on the main evaluation path for
10876 -- expressions.
10881 -- Check for an ambiguous range over character literals. This will
10882 -- happen with a membership test involving only literals.
10890 -- If bounds are static, constant-fold them, so size computations are
10891 -- identical between front-end and back-end. Do not perform this
10892 -- transformation while analyzing generic units, as type information
10893 -- would be lost when reanalyzing the constant node in the instance.
10905 -- If we have a compile-time-known null range, we warn, because that is
10906 -- likely to be a mistake. (Dynamic null ranges make sense, but often
10907 -- compile-time-known ones do not.) Warn only if this is in a subtype
10908 -- declaration. We do this here, rather than while analyzing a subtype
10909 -- declaration, in case we decide to expand the cases. We do not want to
10910 -- warn in all cases, because some are idiomatic, such as an empty
10911 -- aggregate (1 .. 0 => <>).
10913 -- We don't warn in generics or their instances, because there might be
10914 -- some instances where the range is null, and some where it is not,
10915 -- which would lead to false alarms.
10919 and then Compile_Time_Compare
10925 then
10930 --------------------------
10931 -- Resolve_Real_Literal --
10932 --------------------------
10937 begin
10938 -- Special processing for fixed-point literals to make sure that the
10939 -- value is an exact multiple of the small where this is required. We
10940 -- skip this for the universal real case, and also for generic types.
10946 then
10947 -- We must freeze the base type to get the proper value of the small
10953 declare
10960 begin
10961 -- Case of literal is not an exact multiple of the Small
10965 -- For a source program literal for a decimal fixed-point type,
10966 -- this is statically illegal (RM 4.9(36)).
10971 then
10975 -- Generate a warning if literal from source
10978 and then Warn_On_Bad_Fixed_Value
10979 then
10980 Error_Msg_N
10982 N);
10985 -- Replace literal by a value that is the exact representation
10986 -- of a value of the type, i.e. a multiple of the small value,
10987 -- by truncation, since Machine_Rounds is false for all GNAT
10988 -- fixed-point types (RM 4.9(38)).
10998 -- In all cases, set the corresponding integer field
11004 -- Now replace the actual type by the expected type as usual
11010 -----------------------
11011 -- Resolve_Reference --
11012 -----------------------
11017 begin
11018 -- Replace general access with specific type
11026 -- If we are taking the reference of a volatile entity, then treat it as
11027 -- a potential modification of this entity. This is too conservative,
11028 -- but necessary because remove side effects can cause transformations
11029 -- of normal assignments into reference sequences that otherwise fail to
11030 -- notice the modification.
11037 --------------------------------
11038 -- Resolve_Selected_Component --
11039 --------------------------------
11054 -- Check whether this is the initialization of a component within an
11055 -- init proc (by assignment or call to another init proc). If true,
11056 -- there is no need for a discriminant check.
11058 --------------------
11059 -- Init_Component --
11060 --------------------
11063 begin
11064 return Inside_Init_Proc
11070 -- Start of processing for Resolve_Selected_Component
11072 begin
11075 -- Use the context type to select the prefix that has a selector
11076 -- of the correct name and type.
11084 else
11088 -- Locate selected component. For a private prefix the selector
11089 -- can denote a discriminant.
11093 -- The visible components of a class-wide type are those of
11094 -- the root type.
11104 then
11111 else
11115 Error_Msg_N
11120 else
11123 -- There may be an implicit dereference. Retrieve
11124 -- designated record type.
11128 else
11134 -- Resolution chooses the new interpretation.
11135 -- Find the component with the right name.
11140 loop
11157 -- There must be a legal interpretation at this point
11162 -- In general the expected type is the type of the context, not the
11163 -- type of the candidate selected component.
11168 -- The type of the context and that of the component are
11169 -- compatible and in general identical, but if they are anonymous
11170 -- access-to-subprogram types, the relevant type is that of the
11171 -- component. This matters in Unnest_Subprograms mode, where the
11172 -- relevant context is the one in which the type is declared, not
11173 -- the point of use. This determines what activation record to use.
11178 -- When the type of the component is an access to a class-wide type
11179 -- the relevant type is that of the component (since in such case we
11180 -- may need to generate implicit type conversions or dispatching
11181 -- calls).
11186 then
11190 else
11191 -- Resolve prefix with its type
11196 -- Generate cross-reference. We needed to wait until full overloading
11197 -- resolution was complete to do this, since otherwise we can't tell if
11198 -- we are an lvalue or not.
11202 else
11206 -- If the prefix's type is an access type, get to the real record type.
11207 -- Note: we do not apply an access check because an explicit dereference
11208 -- will be introduced later, and the check will happen there.
11214 else
11218 -- Set flag for expander if discriminant check required on a component
11219 -- appearing within a variant.
11225 and then
11228 and then not Init_Component
11229 then
11237 -- If the prefix is a record conversion, this may be a renamed
11238 -- discriminant whose bounds differ from those of the original
11239 -- one, so we must ensure that a range check is performed.
11244 then
11248 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11254 -- If the record type is atomic and the component is not, then this
11255 -- is worth a warning before Ada 2022, since we have a situation
11256 -- where the access to the component may cause extra read/writes of
11257 -- the atomic object, or partial word accesses, both of which may be
11258 -- unexpected.
11264 then
11265 Error_Msg_N
11268 Error_Msg_N
11278 -------------------
11279 -- Resolve_Shift --
11280 -------------------
11287 begin
11288 -- We do the resolution using the base type, because intermediate values
11289 -- in expressions always are of the base type, not a subtype of it.
11302 ---------------------------
11303 -- Resolve_Short_Circuit --
11304 ---------------------------
11311 begin
11312 -- Ensure all actions associated with the left operand (e.g.
11313 -- finalization of transient objects) are fully evaluated locally within
11314 -- an expression with actions. This is particularly helpful for coverage
11315 -- analysis. However this should not happen in generics or if option
11316 -- Minimize_Expression_With_Actions is set.
11319 declare
11321 begin
11329 -- Set Comes_From_Source on L to preserve warnings for unset
11330 -- reference.
11339 -- Check for issuing warning for always False assert/check, this happens
11340 -- when assertions are turned off, in which case the pragma Assert/Check
11341 -- was transformed into:
11343 -- if False and then <condition> then ...
11345 -- and we detect this pattern
11347 if Warn_On_Assertion_Failure
11354 then
11355 declare
11358 begin
11359 -- Special handling of Asssert pragma
11363 then
11364 declare
11366 Original_Node
11367 (Expression
11370 begin
11371 -- Don't warn if original condition is explicit False,
11372 -- since obviously the failure is expected in this case.
11376 then
11379 -- Issue warning. We do not want the deletion of the
11380 -- IF/AND-THEN to take this message with it. We achieve this
11381 -- by making sure that the expanded code points to the Sloc
11382 -- of the expression, not the original pragma.
11384 else
11385 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11386 -- The source location of the expression is not usually
11387 -- the best choice here. For example, it gets located on
11388 -- the last AND keyword in a chain of boolean expressiond
11389 -- AND'ed together. It is best to put the message on the
11390 -- first character of the assertion, which is the effect
11391 -- of the First_Node call here.
11393 Error_Msg_F
11395 Expression
11400 -- Similar processing for Check pragma
11404 then
11405 -- Don't want to warn if original condition is explicit False
11407 declare
11409 Original_Node
11410 (Expression
11412 begin
11415 then
11418 -- Post warning
11420 else
11421 -- Again use Error_Msg_F rather than Error_Msg_N, see
11422 -- comment above for an explanation of why we do this.
11424 Error_Msg_F
11426 Expression
11434 -- Continue with processing of short circuit
11443 -------------------
11444 -- Resolve_Slice --
11445 -------------------
11454 begin
11457 -- Use the context type to select the prefix that yields the correct
11458 -- array type.
11460 declare
11466 begin
11474 then
11482 else
11487 else
11498 else
11504 -- If the prefix's type is an access type, get to the real array type.
11505 -- Note: we do not apply an access check because an explicit dereference
11506 -- will be introduced later, and the check will happen there.
11511 -- If the prefix is an access to an unconstrained array, we must use
11512 -- the actual subtype of the object to perform the index checks. The
11513 -- object denoted by the prefix is implicit in the node, so we build
11514 -- an explicit representation for it in order to compute the actual
11515 -- subtype.
11520 declare
11524 begin
11531 -- In CodePeer mode the attribute Image is not expanded, so when it
11532 -- acts as a prefix of a slice, we handle it like a call to function
11533 -- returning an unconstrained string. Same for the Wide variants of
11534 -- attribute Image.
11543 | Name_Wide_Image
11544 | Name_Wide_Wide_Image)
11545 then
11548 -- If the name is a selected component that depends on discriminants,
11549 -- build an actual subtype for it. This can happen only when the name
11550 -- itself is overloaded; otherwise the actual subtype is created when
11551 -- the selected component is analyzed.
11554 and then Full_Analysis
11556 then
11557 declare
11560 begin
11565 -- Maybe this should just be "else", instead of checking for the
11566 -- specific case of slice??? This is needed for the case where the
11567 -- prefix is an Image attribute, which gets expanded to a slice, and so
11568 -- has a constrained subtype which we want to use for the slice range
11569 -- check applied below (the range check won't get done if the
11570 -- unconstrained subtype of the 'Image is used).
11576 -- Obtain the type of the array index
11580 else
11584 -- If name was overloaded, set slice type correctly now
11588 -- Handle the generation of a range check that compares the array index
11589 -- against the discrete_range. The check is not applied to internally
11590 -- built nodes associated with the expansion of dispatch tables. Check
11591 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11592 -- the unit.
11594 if Tagged_Type_Expansion
11600 then
11603 -- The discrete_range is specified by a subtype name. Create an
11604 -- equivalent range attribute, apply checks to this attribute, but
11605 -- insert them into the range expression of the slice itself.
11608 Dexpr :=
11609 Make_Attribute_Reference
11611 Prefix =>
11620 -- The discrete_range is a regular range (or a range attribute, which
11621 -- will be resolved into a regular range). Resolve the bounds and remove
11622 -- their side effects.
11624 else
11641 -- Check bad use of type with predicates
11643 declare
11646 begin
11649 then
11651 else
11656 Bad_Predicated_Subtype_Use
11661 -- Otherwise here is where we check suspicious indexes
11673 ----------------------------
11674 -- Resolve_String_Literal --
11675 ----------------------------
11686 begin
11687 -- For a string appearing in a concatenation, defer creation of the
11688 -- string_literal_subtype until the end of the resolution of the
11689 -- concatenation, because the literal may be constant-folded away. This
11690 -- is a useful optimization for long concatenation expressions.
11692 -- If the string is an aggregate built for a single character (which
11693 -- happens in a non-static context) or a is null string to which special
11694 -- checks may apply, we build the subtype. Wide strings must also get a
11695 -- string subtype if they come from a one character aggregate. Strings
11696 -- generated by attributes might be static, but it is often hard to
11697 -- determine whether the enclosing context is static, so we generate
11698 -- subtypes for them as well, thus losing some rarer optimizations ???
11699 -- Same for strings that come from a static conversion.
11701 Need_Check :=
11710 -- If the resolving type is itself a string literal subtype, we can just
11711 -- reuse it, since there is no point in creating another.
11717 and then not Need_Check
11719 | N_Attribute_Reference
11720 | N_Qualified_Expression
11721 | N_Type_Conversion
11722 then
11725 -- Do not generate a string literal subtype for the default expression
11726 -- of a formal parameter in GNATprove mode. This is because the string
11727 -- subtype is associated with the freezing actions of the subprogram,
11728 -- however freezing is disabled in GNATprove mode and as a result the
11729 -- subtype is unavailable.
11731 elsif GNATprove_Mode
11733 then
11736 -- Otherwise we must create a string literal subtype. Note that the
11737 -- whole idea of string literal subtypes is simply to avoid the need
11738 -- for building a full fledged array subtype for each literal.
11740 else
11746 or else Need_Check
11747 then
11754 then
11760 -- The validity of a null string has been checked in the call to
11761 -- Eval_String_Literal.
11766 -- Always accept string literal with component type Any_Character, which
11767 -- occurs in error situations and in comparisons of literals, both of
11768 -- which should accept all literals.
11773 -- If the type is bit-packed, then we always transform the string
11774 -- literal into a full fledged aggregate.
11779 -- Deal with cases of Wide_Wide_String, Wide_String, and String
11781 else
11782 -- For Standard.Wide_Wide_String, or any other type whose component
11783 -- type is Standard.Wide_Wide_Character, we know that all the
11784 -- characters in the string must be acceptable, since the parser
11785 -- accepted the characters as valid character literals.
11790 -- For the case of Standard.String, or any other type whose component
11791 -- type is Standard.Character, we must make sure that there are no
11792 -- wide characters in the string, i.e. that it is entirely composed
11793 -- of characters in range of type Character.
11795 -- If the string literal is the result of a static concatenation, the
11796 -- test has already been performed on the components, and need not be
11797 -- repeated.
11801 then
11805 -- If we are out of range, post error. This is one of the
11806 -- very few places that we place the flag in the middle of
11807 -- a token, right under the offending wide character. Not
11808 -- quite clear if this is right wrt wide character encoding
11809 -- sequences, but it's only an error message.
11811 Error_Msg
11818 -- For the case of Standard.Wide_String, or any other type whose
11819 -- component type is Standard.Wide_Character, we must make sure that
11820 -- there are no wide characters in the string, i.e. that it is
11821 -- entirely composed of characters in range of type Wide_Character.
11823 -- If the string literal is the result of a static concatenation,
11824 -- the test has already been performed on the components, and need
11825 -- not be repeated.
11829 then
11833 -- If we are out of range, post error. This is one of the
11834 -- very few places that we place the flag in the middle of
11835 -- a token, right under the offending wide character.
11837 -- This is not quite right, because characters in general
11838 -- will take more than one character position ???
11840 Error_Msg
11847 -- If the root type is not a standard character, then we will convert
11848 -- the string into an aggregate and will let the aggregate code do
11849 -- the checking. Standard Wide_Wide_Character is also OK here.
11851 else
11855 -- See if the component type of the array corresponding to the string
11856 -- has compile time known bounds. If yes we can directly check
11857 -- whether the evaluation of the string will raise constraint error.
11858 -- Otherwise we need to transform the string literal into the
11859 -- corresponding character aggregate and let the aggregate code do
11860 -- the checking. We use the same transformation if the component
11861 -- type has a static predicate, which will be applied to each
11862 -- character when the aggregate is resolved.
11866 -- Check for the case of full range, where we are definitely OK
11872 -- Here the range is not the complete base type range, so check
11874 declare
11882 begin
11885 then
11891 then
11892 Apply_Compile_Time_Constraint_Error
11894 CE_Range_Check_Failed,
11907 -- If we got here we meed to transform the string literal into the
11908 -- equivalent qualified positional array aggregate. This is rather
11909 -- heavy artillery for this situation, but it is hard work to avoid.
11911 declare
11916 begin
11917 -- Build the character literals, we give them source locations that
11918 -- correspond to the string positions, which is a bit tricky given
11919 -- the possible presence of wide character escape sequences.
11933 -- Should we have a call to Skip_Wide here ???
11935 -- ??? else
11936 -- Skip_Wide (P);
11944 Expression =>
11951 -------------------------
11952 -- Resolve_Target_Name --
11953 -------------------------
11956 begin
11960 -----------------------------
11961 -- Resolve_Type_Conversion --
11962 -----------------------------
11974 -- Set to False to suppress cases where we want to suppress the test
11975 -- for redundancy to avoid possible false positives on this warning.
11977 begin
11978 if not Conv_OK
11980 then
11984 -- If the Operand Etype is Universal_Fixed, then the conversion is
11985 -- never redundant. We need this check because by the time we have
11986 -- finished the rather complex transformation, the conversion looks
11987 -- redundant when it is not.
11992 -- If the operand is marked as Any_Fixed, then special processing is
11993 -- required. This is also a case where we suppress the test for a
11994 -- redundant conversion, since most certainly it is not redundant.
11999 -- Mixed-mode operation involving a literal. Context must be a fixed
12000 -- type which is applied to the literal subsequently.
12002 -- Multiplication and division involving two fixed type operands must
12003 -- yield a universal real because the result is computed in arbitrary
12004 -- precision.
12010 then
12016 or else
12018 then
12019 -- Return if expression is ambiguous
12024 -- If nothing else, the available fixed type is Duration
12026 else
12030 -- Resolve the real operand with largest available precision
12034 else
12040 -- If the operand is a literal (it could be a non-static and
12041 -- illegal exponentiation) check whether the use of Duration
12042 -- is potentially inaccurate.
12047 then
12048 Error_Msg_N
12051 Error_Msg_N
12058 then
12061 else
12072 -- Note: we do the Eval_Type_Conversion call before applying the
12073 -- required checks for a subtype conversion. This is important, since
12074 -- both are prepared under certain circumstances to change the type
12075 -- conversion to a constraint error node, but in the case of
12076 -- Eval_Type_Conversion this may reflect an illegality in the static
12077 -- case, and we would miss the illegality (getting only a warning
12078 -- message), if we applied the type conversion checks first.
12082 -- Even when evaluation is not possible, we may be able to simplify the
12083 -- conversion or its expression. This needs to be done before applying
12084 -- checks, since otherwise the checks may use the original expression
12085 -- and defeat the simplifications. This is specifically the case for
12086 -- elimination of the floating-point Truncation attribute in
12087 -- float-to-int conversions.
12091 -- If after evaluation we still have a type conversion, then we may need
12092 -- to apply checks required for a subtype conversion. But skip them if
12093 -- universal fixed operands are involved, since range checks are handled
12094 -- separately for these cases, after the expansion done by Exp_Fixd.
12100 then
12104 -- Issue warning for conversion of simple object to its own type. We
12105 -- have to test the original nodes, since they may have been rewritten
12106 -- by various optimizations.
12110 -- Here we test for a redundant conversion if the warning mode is
12111 -- active (and was not locally reset), and we have a type conversion
12112 -- from source not appearing in a generic instance.
12114 if Test_Redundant
12117 and then not In_Instance
12118 then
12122 -- If the node is part of a larger expression, the Target_Type
12123 -- may not be the original type of the node if the context is a
12124 -- condition. Recover original type to see if conversion is needed.
12128 then
12132 -- If we have an entity name, then give the warning if the entity
12133 -- is the right type, or if it is a loop parameter covered by the
12134 -- original type (that's needed because loop parameters have an
12135 -- odd subtype coming from the bounds).
12139 and then
12141 or else
12145 -- If not an entity, then type of expression must match
12148 then
12149 -- One more check, do not give warning if the analyzed conversion
12150 -- has an expression with non-static bounds, and the bounds of the
12151 -- target are static. This avoids junk warnings in cases where the
12152 -- conversion is necessary to establish staticness, for example in
12153 -- a case statement.
12157 then
12160 -- Finally, if this type conversion occurs in a context requiring
12161 -- a prefix, and the expression is a qualified expression then the
12162 -- type conversion is not redundant, since a qualified expression
12163 -- is not a prefix, whereas a type conversion is. For example, "X
12164 -- := T'(Funx(...)).Y;" is illegal because a selected component
12165 -- requires a prefix, but a type conversion makes it legal: "X :=
12166 -- T(T'(Funx(...))).Y;"
12168 -- In Ada 2012, a qualified expression is a name, so this idiom is
12169 -- no longer needed, but we still suppress the warning because it
12170 -- seems unfriendly for warnings to pop up when you switch to the
12171 -- newer language version.
12175 | N_Indexed_Component
12176 | N_Selected_Component
12177 | N_Slice
12178 | N_Explicit_Dereference
12179 then
12182 -- Never warn on conversion to Long_Long_Integer'Base since
12183 -- that is most likely an artifact of the extended overflow
12184 -- checking and comes from complex expanded code.
12189 -- Here we give the redundant conversion warning. If it is an
12190 -- entity, give the name of the entity in the message. If not,
12191 -- just mention the expression.
12193 else
12196 Error_Msg_NE -- CODEFIX
12199 else
12200 Error_Msg_NE
12208 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12209 -- No need to perform any interface conversion if the type of the
12210 -- expression coincides with the target type.
12213 and then Expander_Active
12215 then
12216 declare
12220 begin
12221 -- If the type of the operand is a limited view, use nonlimited
12222 -- view when available. If it is a class-wide type, recover the
12223 -- class-wide type of the nonlimited view.
12227 then
12232 -- It seems that Non_Limited_View should also be applied for
12233 -- Target when it has a limited view, but that leads to missing
12234 -- error checks on interface conversions further below. ???
12239 -- If the type of the operand is a limited view, use nonlimited
12240 -- view when available. If it is a class-wide type, recover the
12241 -- class-wide type of the nonlimited view.
12245 then
12253 -- If the target type is a limited view, use nonlimited view
12254 -- when available.
12258 then
12266 -- Conversion from interface type
12268 -- It seems that it would be better for the error checks below
12269 -- to be performed as part of Validate_Conversion (and maybe some
12270 -- of the error checks above could be moved as well?). ???
12274 -- Ada 2005 (AI-217): Handle entities from limited views
12278 Error_Msg_NE -- CODEFIX
12281 Error_Msg_N
12283 N);
12286 and then not
12289 then
12291 Error_Msg_NE -- CODEFIX
12294 Error_Msg_N
12296 N);
12298 else
12302 -- Conversion to interface type
12306 -- Handle subtypes
12313 or else Interface_Present_In_Ancestor
12316 then
12318 else
12321 Error_Msg_N
12329 -- Ada 2012: Once the type conversion is resolved, check whether the
12330 -- operand satisfies a static predicate of the target subtype, if any.
12331 -- In the static expression case, a predicate check failure is an error.
12334 Check_Expression_Against_Static_Predicate
12338 -- If at this stage we have a fixed to integer conversion, make sure the
12339 -- Do_Range_Check flag is set, because such conversions in general need
12340 -- a range check. We only need this if expansion is off, see above why.
12343 and then not Expander_Active
12348 then
12352 -- Generating C code a type conversion of an access to constrained
12353 -- array type to access to unconstrained array type involves building
12354 -- a fat pointer which in general cannot be generated on the fly. We
12355 -- remove side effects in order to store the result of the conversion
12356 -- into a temporary.
12358 if Modify_Tree_For_C
12365 then
12370 ----------------------
12371 -- Resolve_Unary_Op --
12372 ----------------------
12381 begin
12382 -- Deal with intrinsic unary operators
12388 then
12393 -- Deal with universal cases
12402 -- Generate warning for negative literal of a modular type, unless it is
12403 -- enclosed directly in a type qualification or a type conversion, as it
12404 -- is likely not what the user intended. We don't issue the warning for
12405 -- the common use of -1 to denote OxFFFF_FFFF...
12407 if Warn_On_Suspicious_Modulus_Value
12412 | N_Type_Conversion
12414 then
12415 Error_Msg_N
12420 Error_Msg_N
12424 -- Generate warning for expressions like abs (x mod 2)
12426 if Warn_On_Redundant_Constructs
12428 then
12432 Error_Msg_N -- CODEFIX
12437 -- Deal with reference generation
12444 -- Set overflow checking bit. Much cleverer code needed here eventually
12445 -- and perhaps the Resolve routines should be separated for the various
12446 -- arithmetic operations, since they will need different processing ???
12454 -- Generate warning for expressions like -5 mod 3 for integers. No need
12455 -- to worry in the floating-point case, since parens do not affect the
12456 -- result so there is no point in giving in a warning.
12458 declare
12467 begin
12468 if Warn_On_Questionable_Missing_Parens
12472 then
12475 -- We are looking for cases where the right operand is not
12476 -- parenthesized, and is a binary operator, multiply, divide, or
12477 -- mod. These are the cases where the grouping can affect results.
12481 then
12482 -- For mod, we always give the warning, since the value is
12483 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12484 -- -(5 mod 315)). But for the other cases, the only concern is
12485 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12486 -- overflows, but (-2) * 64 does not). So we try to give the
12487 -- message only when overflow is possible.
12491 then
12496 else
12502 else
12506 -- Note that the test below is deliberately excluding the
12507 -- largest negative number, since that is a potentially
12508 -- troublesome case (e.g. -2 * x, where the result is the
12509 -- largest negative integer has an overflow with 2 * x).
12516 -- For the multiplication case, the only case we have to worry
12517 -- about is when (-a)*b is exactly the largest negative number
12518 -- so that -(a*b) can cause overflow. This can only happen if
12519 -- a is a power of 2, and more generally if any operand is a
12520 -- constant that is not a power of 2, then the parentheses
12521 -- cannot affect whether overflow occurs. We only bother to
12522 -- test the left most operand
12524 -- Loop looking at left operands for one that has known value
12531 -- Operand value of 0 or 1 skips warning
12536 -- Otherwise check power of 2, if power of 2, warn, if
12537 -- anything else, skip warning.
12539 else
12543 else
12552 -- Keep looking at left operands
12557 -- For rem or "/" we can only have a problematic situation
12558 -- if the divisor has a value of minus one or one. Otherwise
12559 -- overflow is impossible (divisor > 1) or we have a case of
12560 -- division by zero in any case.
12565 then
12569 -- If we fall through warning should be issued
12571 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12573 Error_Msg_N
12580 ----------------------------------
12581 -- Resolve_Unchecked_Expression --
12582 ----------------------------------
12584 procedure Resolve_Unchecked_Expression
12587 is
12588 begin
12593 ---------------------------------------
12594 -- Resolve_Unchecked_Type_Conversion --
12595 ---------------------------------------
12597 procedure Resolve_Unchecked_Type_Conversion
12600 is
12606 begin
12607 -- Resolve operand using its own type
12611 -- If the expression is a conversion to universal integer of an
12612 -- an expression with an integer type, then we can eliminate the
12613 -- intermediate conversion to universal integer.
12618 then
12623 -- In an inlined context, the unchecked conversion may be applied
12624 -- to a literal, in which case its type is the type of the context.
12625 -- (In other contexts conversions cannot apply to literals).
12627 if In_Inlined_Body
12631 then
12639 ------------------------------
12640 -- Rewrite_Operator_As_Call --
12641 ------------------------------
12648 begin
12655 New_N :=
12666 ------------------------------
12667 -- Rewrite_Renamed_Operator --
12668 ------------------------------
12670 procedure Rewrite_Renamed_Operator
12674 is
12679 begin
12680 -- Do not perform this transformation within a pre/postcondition,
12681 -- because the expression will be reanalyzed, and the transformation
12682 -- might affect the visibility of the operator, e.g. in an instance.
12683 -- Note that fully analyzed and expanded pre/postconditions appear as
12684 -- pragma Check equivalents.
12690 -- Likewise when an expression function is being preanalyzed, since the
12691 -- expression will be reanalyzed as part of the generated body.
12694 declare
12696 begin
12699 N_Expression_Function
12700 then
12716 -- Indicate that both the original entity and its renaming are
12717 -- referenced at this point.
12724 -- If the context type is private, add the appropriate conversions so
12725 -- that the operator is applied to the full view. This is done in the
12726 -- routines that resolve intrinsic operators.
12730 when N_Op_Add
12731 | N_Op_Divide
12732 | N_Op_Expon
12733 | N_Op_Mod
12734 | N_Op_Multiply
12735 | N_Op_Rem
12736 | N_Op_Subtract
12737 =>
12740 when N_Op_Abs
12741 | N_Op_Minus
12742 | N_Op_Plus
12743 =>
12752 -----------------------
12753 -- Set_Slice_Subtype --
12754 -----------------------
12756 -- Build an implicit subtype declaration to represent the type delivered by
12757 -- the slice. This is an abbreviated version of an array subtype. We define
12758 -- an index subtype for the slice, using either the subtype name or the
12759 -- discrete range of the slice. To be consistent with index usage elsewhere
12760 -- we create a list header to hold the single index. This list is not
12761 -- otherwise attached to the syntax tree.
12772 begin
12778 else
12779 -- We force the evaluation of a range. This is definitely needed in
12780 -- the renamed case, and seems safer to do unconditionally. Note in
12781 -- any case that since we will create and insert an Itype referring
12782 -- to this range, we must make sure any side effect removal actions
12783 -- are inserted before the Itype definition.
12789 -- If the discrete range is given by a subtype indication, the
12790 -- type of the slice is the base of the subtype mark.
12793 declare
12795 begin
12804 -- Take a new copy of Drange (where bounds have been rewritten to
12805 -- reference side-effect-free names). Using a separate tree ensures
12806 -- that further expansion (e.g. while rewriting a slice assignment
12807 -- into a FOR loop) does not attempt to remove side effects on the
12808 -- bounds again (which would cause the bounds in the index subtype
12809 -- definition to refer to temporaries before they are defined) (the
12810 -- reason is that some names are considered side effect free here
12811 -- for the subtype, but not in the context of a loop iteration
12812 -- scheme).
12834 -- The Etype of the existing Slice node is reset to this slice subtype.
12835 -- Its bounds are obtained from its first index.
12839 -- For bit-packed slice subtypes, freeze immediately (except in the case
12840 -- of being in a "spec expression" where we never freeze when we first
12841 -- see the expression).
12846 -- For all other cases insert an itype reference in the slice's actions
12847 -- so that the itype is frozen at the proper place in the tree (i.e. at
12848 -- the point where actions for the slice are analyzed). Note that this
12849 -- is different from freezing the itype immediately, which might be
12850 -- premature (e.g. if the slice is within a transient scope). This needs
12851 -- to be done only if expansion is enabled.
12858 --------------------------------
12859 -- Set_String_Literal_Subtype --
12860 --------------------------------
12868 begin
12880 -- The low bound is set from the low bound of the corresponding index
12881 -- type. Note that we do not store the high bound in the string literal
12882 -- subtype, but it can be deduced if necessary from the length and the
12883 -- low bound.
12888 -- If the lower bound is not static we create a range for the string
12889 -- literal, using the index type and the known length of the literal.
12890 -- If the length is 1, then the upper bound is set to a mere copy of
12891 -- the lower bound; or else, if the index type is a signed integer,
12892 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
12893 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
12895 else
12896 declare
12906 begin
12911 High_Bound :=
12916 else
12917 High_Bound :=
12920 Prefix =>
12924 Left_Opnd =>
12927 Prefix =>
12929 Expressions =>
12931 Right_Opnd =>
12936 Set_String_Literal_Low_Bound
12939 else
12940 -- If the index type is an enumeration type, build bounds
12941 -- expression with attributes.
12943 Set_String_Literal_Low_Bound
12947 Prefix =>
12951 Analyze_And_Resolve
12954 -- Build bona fide subtype for the string, and wrap it in an
12955 -- unchecked conversion, because the back end expects the
12956 -- String_Literal_Subtype to have a static lower bound.
12958 Index_Subtype :=
12965 -- In this context, the Index_Type may already have a constraint,
12966 -- so use common base type on string subtype. The base type may
12967 -- be used when generating attributes of the string, for example
12968 -- in the context of a slice assignment.
12990 ------------------------------
12991 -- Simplify_Type_Conversion --
12992 ------------------------------
12995 begin
12997 declare
13002 begin
13003 -- Special processing if the conversion is the expression of a
13004 -- Rounding or Truncation attribute reference. In this case we
13005 -- replace:
13007 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
13009 -- by
13011 -- ityp (x)
13013 -- with the Float_Truncate flag set to False or True respectively,
13014 -- which is more efficient. We reuse Rounding for Machine_Rounding
13015 -- as System.Fat_Gen, which is a permissible behavior.
13018 and then
13024 | Name_Machine_Rounding
13025 | Name_Truncation
13026 then
13027 declare
13030 begin
13036 -- Special processing for the conversion of an integer literal to
13037 -- a dynamic type: we first convert the literal to the root type
13038 -- and then convert the result to the target type, the goal being
13039 -- to avoid doing range checks in universal integer.
13045 then
13049 -- If the expression is a conversion to universal integer of an
13050 -- an expression with an integer type, then we can eliminate the
13051 -- intermediate conversion to universal integer.
13056 then
13064 ------------------------------
13065 -- Try_User_Defined_Literal --
13066 ------------------------------
13068 function Try_User_Defined_Literal
13071 is
13072 begin
13074 | N_Op_Rem | N_Op_Subtract
13075 then
13077 -- Both operands must have the same type as the context.
13078 -- (ignoring for now fixed-point and exponentiation ops).
13086 if
13088 then
13093 else
13098 -- For other operators the context does not impose a type on
13099 -- the operands, but their types must match.
13103 and then
13104 Has_Applicable_User_Defined_Literal
13106 then
13112 and then
13113 Has_Applicable_User_Defined_Literal
13115 then
13118 else
13123 and then
13125 then
13134 -----------------------------
13135 -- Unique_Fixed_Point_Type --
13136 -----------------------------
13140 -- Give error messages for true ambiguity. Messages are posted on node
13141 -- N, and entities T1, T2 are the possible interpretations.
13143 -----------------------
13144 -- Fixed_Point_Error --
13145 -----------------------
13148 begin
13154 -- Local variables
13162 -- Start of processing for Unique_Fixed_Point_Type
13164 begin
13165 -- The operations on Duration are visible, so Duration is always a
13166 -- possible interpretation.
13170 -- Look for fixed-point types in enclosing scopes
13179 then
13183 else
13194 -- Look for visible fixed type declarations in the context
13205 then
13209 else
13224 else
13225 -- When the context is a type conversion, issue the warning on the
13226 -- expression of the conversion because it is the actual operation.
13230 else
13234 Error_Msg_NE
13241 ----------------------
13242 -- Valid_Conversion --
13243 ----------------------
13245 function Valid_Conversion
13250 is
13255 function Conversion_Check
13258 -- Little routine to post Msg if Valid is False, returns Valid value
13261 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13263 procedure Conversion_Error_NE
13267 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13270 -- Return True if expression is within an instance but is not in one of
13271 -- the actuals of the instantiation. Type conversions within an instance
13272 -- are not rechecked because type visibility may lead to spurious errors
13273 -- but conversions in an actual for a formal object must be checked.
13275 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13277 -- Implicit anonymous-to-named access type conversions are not allowed
13278 -- if the "statically deeper than" relationship does not apply to the
13279 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13280 -- We deal with most such cases elsewhere so that we can emit more
13281 -- specific error messages (e.g., if the operand is an access parameter
13282 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13283 -- here is where we catch the case where the operand is an access
13284 -- discriminant selected from a dereference of another such "bad"
13285 -- conversion argument.
13287 function Valid_Tagged_Conversion
13290 -- Specifically test for validity of tagged conversions
13293 -- Check index and component conformance, and accessibility levels if
13294 -- the component types are anonymous access types (Ada 2005).
13296 ----------------------
13297 -- Conversion_Check --
13298 ----------------------
13300 function Conversion_Check
13303 is
13304 begin
13305 if not Valid
13307 -- A generic unit has already been analyzed and we have verified
13308 -- that a particular conversion is OK in that context. Since the
13309 -- instance is reanalyzed without relying on the relationships
13310 -- established during the analysis of the generic, it is possible
13311 -- to end up with inconsistent views of private types. Do not emit
13312 -- the error message in such cases. The rest of the machinery in
13313 -- Valid_Conversion still ensures the proper compatibility of
13314 -- target and operand types.
13316 and then not In_Instance_Code
13317 then
13324 ------------------------
13325 -- Conversion_Error_N --
13326 ------------------------
13329 begin
13335 -------------------------
13336 -- Conversion_Error_NE --
13337 -------------------------
13339 procedure Conversion_Error_NE
13343 is
13344 begin
13350 ----------------------
13351 -- In_Instance_Code --
13352 ----------------------
13357 begin
13361 else
13365 -- The expression is part of an actual object if it appears in
13366 -- the generated object declaration in the instance.
13370 then
13373 else
13374 exit when
13383 -- Otherwise the expression appears within the instantiated unit
13389 --------------------------------------------------
13390 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13391 --------------------------------------------------
13393 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13395 is
13401 begin
13413 -- return False if Expr not of form <prefix>.all.Some_Component
13417 then
13418 -- conditional expressions, declare expressions ???
13425 -- The "statically deeper relationship" does not apply
13426 -- to generic formal access types, so a prefix of such
13427 -- a type is a "bad" prefix.
13432 -- The "statically deeper relationship" does apply to
13433 -- any other named access type.
13442 -- The "statically deeper relationship" applies to some
13443 -- anonymous access types and not to others. Return
13444 -- True for the cases where it does not apply. Also check
13445 -- recursively for the
13446 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13447 -- where the correct result depends on <prefix>.
13450 N_Procedure_Specification | -- access parameter
13451 N_Function_Specification | -- access parameter
13452 N_Object_Declaration -- saooaaat
13456 ----------------------------
13457 -- Valid_Array_Conversion --
13458 ----------------------------
13475 begin
13476 -- Error if wrong number of dimensions
13478 if
13480 then
13481 Conversion_Error_N
13485 -- Number of dimensions matches
13487 else
13488 -- Loop through indexes of the two arrays
13496 -- Error if index types are incompatible
13502 then
13503 Conversion_Error_N
13505 Operand);
13513 -- If component types have same base type, all set
13518 -- Here if base types of components are not the same. The only
13519 -- time this is allowed is if we have anonymous access types.
13521 -- The conversion of arrays of anonymous access types can lead
13522 -- to dangling pointers. AI-392 formalizes the accessibility
13523 -- checks that must be applied to such conversions to prevent
13524 -- out-of-scope references.
13527 E_Anonymous_Access_Type
13528 | E_Anonymous_Access_Subprogram_Type
13530 and then
13532 then
13535 then
13538 Conversion_Error_N
13548 -- Conversion not allowed because of accessibility levels
13550 else
13551 Conversion_Error_N
13557 else
13561 -- All other cases where component base types do not match
13563 else
13564 Conversion_Error_N
13566 Operand);
13570 -- Check that component subtypes statically match. For numeric
13571 -- types this means that both must be either constrained or
13572 -- unconstrained. For enumeration types the bounds must match.
13573 -- All of this is checked in Subtypes_Statically_Match.
13575 if not Subtypes_Statically_Match
13577 then
13578 Conversion_Error_N
13587 -----------------------------
13588 -- Valid_Tagged_Conversion --
13589 -----------------------------
13591 function Valid_Tagged_Conversion
13594 is
13595 begin
13596 -- Upward conversions are allowed (RM 4.6(22))
13600 then
13603 -- Downward conversion are allowed if the operand is class-wide
13604 -- (RM 4.6(23)).
13608 then
13613 then
13614 return
13618 -- Ada 2005 (AI-251): The conversion to/from interface types is
13619 -- always valid. The types involved may be class-wide (sub)types.
13623 then
13626 -- If the operand is a class-wide type obtained through a limited_
13627 -- with clause, and the context includes the nonlimited view, use
13628 -- it to determine whether the conversion is legal.
13634 then
13639 then
13642 else
13643 Conversion_Error_NE
13650 -- Start of processing for Valid_Conversion
13652 begin
13656 declare
13664 begin
13665 -- Remove procedure calls, which syntactically cannot appear in
13666 -- this context, but which cannot be removed by type checking,
13667 -- because the context does not impose a type.
13669 -- The node may be labelled overloaded, but still contain only one
13670 -- interpretation because others were discarded earlier. If this
13671 -- is the case, retain the single interpretation if legal.
13679 then
13680 -- More than one candidate interpretation is available
13688 -- When compiling for a system where Address is of a visible
13689 -- integer type, spurious ambiguities can be produced when
13690 -- arithmetic operations have a literal operand and return
13691 -- System.Address or a descendant of it. These ambiguities
13692 -- are usually resolved by the context, but for conversions
13693 -- there is no context type and the removal of the spurious
13694 -- operations must be done explicitly here.
13696 if not Address_Is_Private
13698 then
13723 Conversion_Error_N
13726 -- If the interpretation involves a standard operator, use
13727 -- the location of the type, which may be user-defined.
13731 else
13735 Conversion_Error_N -- CODEFIX
13740 else
13744 Conversion_Error_N -- CODEFIX
13756 -- Deal with conversion of integer type to address if the pragma
13757 -- Allow_Integer_Address is in effect. We convert the conversion to
13758 -- an unchecked conversion in this case and we are all done.
13766 -- If we are within a child unit, check whether the type of the
13767 -- expression has an ancestor in a parent unit, in which case it
13768 -- belongs to its derivation class even if the ancestor is private.
13769 -- See RM 7.3.1 (5.2/3).
13773 -- Numeric types
13777 -- A universal fixed expression can be converted to any numeric type
13782 -- Also no need to check when in an instance or inlined body, because
13783 -- the legality has been established when the template was analyzed.
13784 -- Furthermore, numeric conversions may occur where only a private
13785 -- view of the operand type is visible at the instantiation point.
13786 -- This results in a spurious error if we check that the operand type
13787 -- is a numeric type.
13789 -- Note: in a previous version of this unit, the following tests were
13790 -- applied only for generated code (Comes_From_Source set to False),
13791 -- but in fact the test is required for source code as well, since
13792 -- this situation can arise in source code.
13797 -- Otherwise we need the conversion check
13799 else
13800 return Conversion_Check
13802 or else
13808 -- Array types
13814 then
13815 Conversion_Error_N
13819 else
13823 -- Ada 2005 (AI-251): Internally generated conversions of access to
13824 -- interface types added to force the displacement of the pointer to
13825 -- reference the corresponding dispatch table.
13830 then
13833 -- Ada 2005 (AI-251): Anonymous access types where target references an
13834 -- interface type.
13838 E_General_Access_Type | E_Anonymous_Access_Type
13840 then
13841 -- Check the static accessibility rule of 4.6(17). Note that the
13842 -- check is not enforced when within an instance body, since the
13843 -- RM requires such cases to be caught at run time.
13845 -- If the operand is a rewriting of an allocator no check is needed
13846 -- because there are no accessibility issues.
13854 then
13855 -- In an instance, this is a run-time check, but one we know
13856 -- will fail, so generate an appropriate warning. The raise
13857 -- will be generated by Expand_N_Type_Conversion.
13861 Conversion_Error_N
13863 Operand);
13866 else
13867 Conversion_Error_N
13869 Operand);
13873 -- Special accessibility checks are needed in the case of access
13874 -- discriminants declared for a limited type.
13878 then
13879 -- When the operand is a selected access discriminant the check
13880 -- needs to be made against the level of the object denoted by
13881 -- the prefix of the selected name (Accessibility_Level handles
13882 -- checking the prefix of the operand for this case).
13885 and then Static_Accessibility_Level
13888 then
13889 -- In an instance, this is a run-time check, but one we know
13890 -- will fail, so generate an appropriate warning. The raise
13891 -- will be generated by Expand_N_Type_Conversion.
13895 Conversion_Error_N
13900 -- Real error if not in instance body
13902 else
13903 Conversion_Error_N
13910 -- The case of a reference to an access discriminant from
13911 -- within a limited type declaration (which will appear as
13912 -- a discriminal) is always illegal because the level of the
13913 -- discriminant is considered to be deeper than any (nameable)
13914 -- access type.
13918 and then
13921 then
13922 Conversion_Error_N
13924 Operand);
13932 -- General and anonymous access types
13935 E_General_Access_Type | E_Anonymous_Access_Type
13936 and then
13937 Conversion_Check
13939 and then
13941 E_Access_Subprogram_Type |
13942 E_Access_Protected_Subprogram_Type,
13944 then
13947 then
13948 Conversion_Error_N
13953 -- Check the static accessibility rule of 4.6(17). Note that the
13954 -- check is not enforced when within an instance body, since the RM
13955 -- requires such cases to be caught at run time.
13960 N_Object_Declaration
13961 then
13962 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
13963 -- conversions from an anonymous access type to a named general
13964 -- access type. Such conversions are not allowed in the case of
13965 -- access parameters and stand-alone objects of an anonymous
13966 -- access type. The implicit conversion case is recognized by
13967 -- testing that Comes_From_Source is False and that it's been
13968 -- rewritten. The Comes_From_Source test isn't sufficient because
13969 -- nodes in inlined calls to predefined library routines can have
13970 -- Comes_From_Source set to False. (Is there a better way to test
13971 -- for implicit conversions???).
13972 --
13973 -- Do not treat a rewritten 'Old attribute reference like other
13974 -- rewrite substitutions. This makes a difference, for example,
13975 -- in the case where we are generating the expansion of a
13976 -- membership test of the form
13977 -- Saooaaat'Old in Named_Access_Type
13978 -- because in this case Valid_Conversion needs to return True
13979 -- (otherwise the expansion will be False - see the call site
13980 -- in exp_ch4.adb).
13988 then
13991 -- When applying restriction No_Dynamic_Accessibility_Check,
13992 -- implicit conversions are allowed when the operand type is
13993 -- not deeper than the target type.
13998 then
13999 Conversion_Error_N
14003 -- Implicit conversions aren't allowed for objects of an
14004 -- anonymous access type, since such objects have nonstatic
14005 -- levels in Ada 2012.
14008 = N_Object_Declaration
14009 then
14010 Conversion_Error_N
14015 -- Implicit conversions aren't allowed for anonymous access
14016 -- parameters. We exclude anonymous access results as well
14017 -- as universal_access "=".
14021 N_Function_Specification |
14022 N_Procedure_Specification
14024 then
14025 Conversion_Error_N
14030 -- Detect access discriminant values that are illegal
14031 -- implicit anonymous-to-named access conversion operands.
14034 then
14035 Conversion_Error_N
14040 -- In other cases, the level of the operand's type must be
14041 -- statically less deep than that of the target type, else
14042 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
14046 then
14047 Conversion_Error_N
14054 -- Check if the operand is deeper than the target type, taking
14055 -- care to avoid the case where we are converting a result of a
14056 -- function returning an anonymous access type since the "master
14057 -- of the call" would be target type of the conversion unless
14058 -- the target type is anonymous access as well - see RM 3.10.2
14059 -- (10.3/3).
14061 -- Note that when the restriction No_Dynamic_Accessibility_Checks
14062 -- is in effect wei also want to proceed with the conversion check
14063 -- described above.
14068 /= N_Function_Specification
14072 -- Check we are not in a return value ???
14075 or else
14078 then
14079 -- In an instance, this is a run-time check, but one we know
14080 -- will fail, so generate an appropriate warning. The raise
14081 -- will be generated by Expand_N_Type_Conversion.
14085 Conversion_Error_N
14087 Operand);
14090 -- If not in an instance body, this is a real error
14092 else
14093 -- Avoid generation of spurious error message
14096 Conversion_Error_N
14098 Operand);
14104 -- Special accessibility checks are needed in the case of access
14105 -- discriminants declared for a limited type.
14109 then
14110 -- When the operand is a selected access discriminant the check
14111 -- needs to be made against the level of the object denoted by
14112 -- the prefix of the selected name (Accessibility_Level handles
14113 -- checking the prefix of the operand for this case).
14116 and then Static_Accessibility_Level
14119 then
14120 -- In an instance, this is a run-time check, but one we know
14121 -- will fail, so generate an appropriate warning. The raise
14122 -- will be generated by Expand_N_Type_Conversion.
14126 Conversion_Error_N
14131 -- If not in an instance body, this is a real error
14133 else
14134 Conversion_Error_N
14141 -- The case of a reference to an access discriminant from
14142 -- within a limited type declaration (which will appear as
14143 -- a discriminal) is always illegal because the level of the
14144 -- discriminant is considered to be deeper than any (nameable)
14145 -- access type.
14148 and then
14151 then
14152 Conversion_Error_N
14154 Operand);
14160 -- In the presence of limited_with clauses we have to use nonlimited
14161 -- views, if available.
14165 -- Helper function to handle limited views
14167 --------------------------
14168 -- Full_Designated_Type --
14169 --------------------------
14174 begin
14175 -- Handle the limited view of a type
14179 then
14181 else
14186 -- Local Declarations
14194 -- Start of processing for Check_Limited
14196 begin
14200 else
14202 Conversion_Error_NE
14207 -- Ada 2005 AI-384: legality rule is symmetric in both
14208 -- designated types. The conversion is legal (with possible
14209 -- constraint check) if either designated type is
14210 -- unconstrained.
14213 or else
14215 and then
14218 then
14219 -- Special case, if Value_Size has been used to make the
14220 -- sizes different, the conversion is not allowed even
14221 -- though the subtypes statically match.
14226 then
14227 Conversion_Error_NE
14230 Conversion_Error_NE
14235 -- Normal case where conversion is allowed
14237 else
14241 else
14242 Error_Msg_NE
14250 -- Access to subprogram types. If the operand is an access parameter,
14251 -- the type has a deeper accessibility that any master, and cannot be
14252 -- assigned. We must make an exception if the conversion is part of an
14253 -- assignment and the target is the return object of an extended return
14254 -- statement, because in that case the accessibility check takes place
14255 -- after the return.
14259 -- Note: this test of Opnd_Type is there to prevent entering this
14260 -- branch in the case of a remote access to subprogram type, which
14261 -- is internally represented as an E_Record_Type.
14264 then
14268 and then
14272 then
14273 Conversion_Error_N
14275 Operand);
14276 Conversion_Error_N
14279 Operand);
14281 Error_Msg_NE
14286 -- Check that the designated types are subtype conformant
14292 -- Check the static accessibility rule of 4.6(20)
14296 then
14297 Conversion_Error_N
14299 Operand);
14301 -- Check that if the operand type is declared in a generic body,
14302 -- then the target type must be declared within that same body
14303 -- (enforces last sentence of 4.6(20)).
14306 declare
14312 begin
14319 Conversion_Error_N
14326 -- Check that the strub modes are compatible.
14327 -- We wish to reject explicit conversions only for
14328 -- incompatible modes.
14330 return Conversion_Check
14331 (Compatible_Strub_Modes
14336 -- Remote access to subprogram types
14340 then
14341 -- It is valid to convert from one RAS type to another provided
14342 -- that their specification statically match.
14344 -- Note: at this point, remote access to subprogram types have been
14345 -- expanded to their E_Record_Type representation, and we need to
14346 -- go back to the original access type definition using the
14347 -- Corresponding_Remote_Type attribute in order to check that the
14348 -- designated profiles match.
14353 Check_Subtype_Conformant
14356 Old_Id =>
14358 Err_Loc =>
14359 N);
14361 -- Check that the strub modes are compatible.
14362 -- We wish to reject explicit conversions only for
14363 -- incompatible modes.
14365 return Conversion_Check
14366 (Compatible_Strub_Modes
14371 -- If it was legal in the generic, it's legal in the instance
14376 -- If both are tagged types, check legality of view conversions
14379 and then
14381 then
14384 -- Types derived from the same root type are convertible
14389 -- In an instance or an inlined body, there may be inconsistent views of
14390 -- the same type, or of types derived from a common root.
14393 and then
14396 then
14399 -- Special check for common access type error case
14403 then
14405 Conversion_Error_NE -- CODEFIX
14409 -- Here we have a real conversion error
14411 else
14412 -- Check for missing regular with_clause when only a limited view of
14413 -- target is available.
14416 Conversion_Error_NE
14419 Conversion_Error_NE
14424 and then In_Package_Body
14425 then
14426 Conversion_Error_NE
14428 Conversion_Error_NE
14432 else
14433 Conversion_Error_NE